Hendricks, R. C.; Braun, M. J.; Mullen, R. L.
1986-01-01
In systems where the design inlet and outlet pressure P sub amb are maintained above the thermodynamic critical pressure P sub c, it is often assumed that heat and mass transfer are governed by single-phase relations and that two-phase flows cannot occur. This simple rule of thumb is adequate in many low-power designs but is inadequate for high-performance turbomachines, boilers, and other systems where two-phase regions can exist even though P sub amb P sub c. Heat and mass transfer and rotordynamic-fluid-mechanic restoring forces depend on momentum differences, and those for a two-phase zone can differ significantly from those for a single-phase zone. By using a laminar, variable-property bearing code and a rotating boiler code, pressure and temperature surfaces were determined that illustrate nesting of a two-phase region within a supercritical pressure region. The method of corresponding states is applied to bearings with reasonable rapport.
Universality of P−V criticality in horizon thermodynamics
Energy Technology Data Exchange (ETDEWEB)
Hansen, Devin; Kubizňák, David [Perimeter Institute,31 Caroline St. N., Waterloo, Ontario, N2L 2Y5 (Canada); Department of Physics and Astronomy, University of Waterloo,Waterloo, Ontario, N2L 3G1 (Canada); Mann, Robert B. [Department of Physics and Astronomy, University of Waterloo,Waterloo, Ontario, N2L 3G1 (Canada)
2017-01-11
We study P−V criticality of black holes in Lovelock gravities in the context of horizon thermodynamics. The corresponding first law of horizon thermodynamics emerges as one of the Einstein-Lovelock equations and assumes the universal (independent of matter content) form δE=TδS−PδV, where P is identified with the total pressure of all matter in the spacetime (including a cosmological constant Λ if present). We compare this approach to recent advances in extended phase space thermodynamics of asymptotically AdS black holes where the ‘standard’ first law of black hole thermodynamics is extended to include a pressure-volume term, where the pressure is entirely due to the (variable) cosmological constant. We show that both approaches are quite different in interpretation. Provided there is sufficient non-linearity in the gravitational sector, we find that horizon thermodynamics admits the same interesting black hole phase behaviour seen in the extended case, such as a Hawking-Page transition, Van der Waals like behaviour, and the presence of a triple point. We also formulate the Smarr formula in horizon thermodynamics and discuss the interpretation of the quantity E appearing in the horizon first law.
Universality of P−V criticality in horizon thermodynamics
International Nuclear Information System (INIS)
Hansen, Devin; Kubizňák, David; Mann, Robert B.
2017-01-01
We study P−V criticality of black holes in Lovelock gravities in the context of horizon thermodynamics. The corresponding first law of horizon thermodynamics emerges as one of the Einstein-Lovelock equations and assumes the universal (independent of matter content) form δE=TδS−PδV, where P is identified with the total pressure of all matter in the spacetime (including a cosmological constant Λ if present). We compare this approach to recent advances in extended phase space thermodynamics of asymptotically AdS black holes where the ‘standard’ first law of black hole thermodynamics is extended to include a pressure-volume term, where the pressure is entirely due to the (variable) cosmological constant. We show that both approaches are quite different in interpretation. Provided there is sufficient non-linearity in the gravitational sector, we find that horizon thermodynamics admits the same interesting black hole phase behaviour seen in the extended case, such as a Hawking-Page transition, Van der Waals like behaviour, and the presence of a triple point. We also formulate the Smarr formula in horizon thermodynamics and discuss the interpretation of the quantity E appearing in the horizon first law.
Thermodynamic properties of pressurized PH3 superconductor
Koka, S.; Rao, G. Venugopal
2018-05-01
The paper presents the superconducting thermodynamic functions determined for pressurized phosphorus trihydride (PH3). In particular, free energy difference ΔF, thermodynamic critical field Hc, specific heat etc. have been calculated using analytical expressions. The calculations were performed in the frame work of the strong-coupling formalism. The obtained dimensionless parameters: RΔ ≡ 2Δ(0)/kBTc, RC ≡ ΔC(Tc)/CN(Tc) and RH≡TcCN(Tc)/Hc2(0) are 4.05, 1.96 and 0.156 respectively, which significantly differ from the values arising from the BCS theory of superconductivity. The thermodynamic properties strongly depend on the depairing electron correlations and retardation effects.
Thermodynamics of negative absolute pressures
International Nuclear Information System (INIS)
Lukacs, B.; Martinas, K.
1984-03-01
The authors show that the possibility of negative absolute pressure can be incorporated into the axiomatic thermodynamics, analogously to the negative absolute temperature. There are examples for such systems (GUT, QCD) processing negative absolute pressure in such domains where it can be expected from thermodynamical considerations. (author)
Gauss-Bonnet coupling constant as a free thermodynamical variable and the associated criticality
International Nuclear Information System (INIS)
Xu, Wei; Xu, Hao; Zhao, Liu
2014-01-01
The thermodynamic phase space of Gauss-Bonnet (GB) AdS black holes is extended, taking the inverse of the GB coupling constant as a new thermodynamic pressure P GB . We studied the critical behavior associated with P GB in the extended thermodynamic phase space at fixed cosmological constant and electric charge. The result shows that when the black holes are neutral, the associated critical points can only exist in five dimensional GB-AdS black holes with spherical topology, and the corresponding critical exponents are identical to those for the Van der Waals system. For charged GB-AdS black holes, it is shown that there can be only one critical point in five dimensions (for black holes with either spherical or hyperbolic topologies), which also requires the electric charge to be bounded within some appropriate range; while in d < 5 dimensions, there can be up to two different critical points at the same electric charge, and the phase transition can occur only at temperatures which are not in between the two critical values. (orig.)
Pressure and volume in the first law of black hole thermodynamics
Dolan, Brian P.
2011-12-01
The mass of a black hole is interpreted, in terms of thermodynamic potentials, as being the enthalpy, with the pressure given by the cosmological constant. The volume is then defined as being the Legendre transform of the pressure, and the resulting relation between volume and pressure is explored in the case of positive pressure. A virial expansion is developed and a van der Waals like critical point determined. The first law of black hole thermodynamics includes a PdV term which modifies the maximal efficiency of a Penrose process. It is shown that, in four-dimensional spacetime with a negative cosmological constant, an extremal charged rotating black hole can have an efficiency of up to 75%, while for an electrically neutral rotating black hole this figure is reduced to 52%, compared to the corresponding values of 50% and 29% respectively when the cosmological constant is zero.
Pressure and volume in the first law of black hole thermodynamics
International Nuclear Information System (INIS)
Dolan, Brian P
2011-01-01
The mass of a black hole is interpreted, in terms of thermodynamic potentials, as being the enthalpy, with the pressure given by the cosmological constant. The volume is then defined as being the Legendre transform of the pressure, and the resulting relation between volume and pressure is explored in the case of positive pressure. A virial expansion is developed and a van der Waals like critical point determined. The first law of black hole thermodynamics includes a PdV term which modifies the maximal efficiency of a Penrose process. It is shown that, in four-dimensional spacetime with a negative cosmological constant, an extremal charged rotating black hole can have an efficiency of up to 75%, while for an electrically neutral rotating black hole this figure is reduced to 52%, compared to the corresponding values of 50% and 29% respectively when the cosmological constant is zero. (paper)
Parachors in terms of critical temperature, critical pressure and acentric factor
Energy Technology Data Exchange (ETDEWEB)
Broseta, D.; Ragil, K.
1995-12-31
The method of parachors is widely used in conventional thermodynamic codes and reservoir simulators to calculate oil/gas interfacial tensions of complex hydrocarbon mixtures. In the low-to-moderate interfacial tension regime, a value p{approx}11/3 has previously been shown to be the {open_quotes}best{close_quotes} parachor exponent. This exponent is a critical exponent and its value is consistent with the values of critical exponents characterizing the liquid/vapor critical behavior. Therefore parachors may be viewed as critical amplitudes. By using critical scaling theory, parachors are related to other critical amplitudes and critical parameters that describe the bulk thermodynamic behavior of fluids. A simple expression relating the parachor of a pure compound to its critical temperature T{sub c}, critical pressure P{sub c}, and acentric factor {omega} is proposed: P= (0.85-0.19{omega})T{sub c}{sup 12/11}/P{sub c}{sup 9/11} where the parachor P is in units of (dyn/cm){sup 3/11}cm{sup 3}/mol, T{sub c} in K and P{sub c} in MPa. This equation matches (within experimental error) the known parachor values of normal fluids (e.g. alkanes, aromatics, CO{sub 2}, N{sub 2}, H{sub 2}S, etc...).
Haldar, Amritendu; Biswas, Ritabrata
2018-06-01
We investigate the effect of thermal fluctuations on the thermodynamics of a Lovelock-AdS black hole. Taking the first order logarithmic correction term in entropy we analyze the thermodynamic potentials like Helmholtz free energy, enthalpy and Gibbs free energy. We find that all the thermodynamic potentials are decreasing functions of correction coefficient α . We also examined this correction coefficient must be positive by analysing P{-}V diagram. Further we study the P{-}V criticality and stability and find that presence of logarithmic correction in it is necessary to have critical points and stable phases. When P{-}V criticality appears, we calculate the critical volume V_c, critical pressure P_c and critical temperature T_c using different equations and show that there is no critical point for this black hole without thermal fluctuations. We also study the geometrothermodynamics of this kind of black holes. The Ricci scalar of the Ruppeiner metric is graphically analysed.
Energy Technology Data Exchange (ETDEWEB)
Klier, Kamil; Landskron, Kai
2015-11-19
We report the feasibility of the thermodynamically controlled synthesis of crystalline sp3-carbon networks. We show that there is a critical pressure below which decomposition of the carbon network is favored and above which the carbon network is stable. Based on advanced, highly accurate quantum mechanical calculations using the all-electron full-potential linearized augmented plane-wave method (FP-LAPW) and the Birch–Murnaghan equation of state, this critical pressure is 26.5 GPa (viz. table of contents graphic). Such pressures are experimentally readily accessible and afford thermodynamic control for suppression of decomposition reactions. The present results further suggest that a general pattern of pressure-directed control exists for many isolobal conversions of sp2 to sp3 allotropes, relating not only to fluorocarbon chemistry but also extending to inorganic and solid-state materials science.
Geometrical thermodynamics and P-V criticality of the black holes with power-law Maxwell field
Energy Technology Data Exchange (ETDEWEB)
Hendi, S.H.; Panah, B.E. [Shiraz University, Physics Department and Biruni Observatory, College of Sciences, Shiraz (Iran, Islamic Republic of); Research Institute for Astronomy and Astrophysics of Maragha (RIAAM), Maragha (Iran, Islamic Republic of); Panahiyan, S. [Shiraz University, Physics Department and Biruni Observatory, College of Sciences, Shiraz (Iran, Islamic Republic of); Shahid Beheshti University, Physics Department, Tehran (Iran, Islamic Republic of); Talezadeh, M.S. [Shiraz University, Physics Department and Biruni Observatory, College of Sciences, Shiraz (Iran, Islamic Republic of)
2017-02-15
We study the thermodynamical structure of Einstein black holes in the presence of power Maxwell invariant nonlinear electrodynamics for two different cases. The behavior of temperature and conditions regarding the stability of these black holes are investigated. Since the language of geometry is an effective method in general relativity, we concentrate on the geometrical thermodynamics to build a phase space for studying thermodynamical properties of these black holes. In addition, taking into account the denominator of the heat capacity, we use the proportionality between cosmological constant and thermodynamical pressure to extract the critical values for these black holes. Besides, the effects of the variation of different parameters on the thermodynamical structure of these black holes are investigated. Furthermore, some thermodynamical properties such as the volume expansion coefficient, speed of sound, and isothermal compressibility coefficient are calculated and some remarks regarding these quantities are given. (orig.)
Geometrical thermodynamics and P-V criticality of the black holes with power-law Maxwell field
International Nuclear Information System (INIS)
Hendi, S.H.; Panah, B.E.; Panahiyan, S.; Talezadeh, M.S.
2017-01-01
We study the thermodynamical structure of Einstein black holes in the presence of power Maxwell invariant nonlinear electrodynamics for two different cases. The behavior of temperature and conditions regarding the stability of these black holes are investigated. Since the language of geometry is an effective method in general relativity, we concentrate on the geometrical thermodynamics to build a phase space for studying thermodynamical properties of these black holes. In addition, taking into account the denominator of the heat capacity, we use the proportionality between cosmological constant and thermodynamical pressure to extract the critical values for these black holes. Besides, the effects of the variation of different parameters on the thermodynamical structure of these black holes are investigated. Furthermore, some thermodynamical properties such as the volume expansion coefficient, speed of sound, and isothermal compressibility coefficient are calculated and some remarks regarding these quantities are given. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Hendi, S.H. [Shiraz University, Physics Department and Biruni Observatory, College of Sciences, Shiraz (Iran, Islamic Republic of); Research Institute for Astronomy and Astrophysics of Maragha (RIAAM), P. O. Box 55134-441, Maragha (Iran, Islamic Republic of); Tad, R.M.; Armanfard, Z.; Talezadeh, M.S. [Shiraz University, Physics Department and Biruni Observatory, College of Sciences, Shiraz (Iran, Islamic Republic of)
2016-05-15
Motivated by a thermodynamic analogy of black holes and Van der Waals liquid/gas systems, in this paper, we study P-V criticality of both dilatonic Born-Infeld black holes and their conformal solutions, Brans-Dicke-Born-Infeld solutions. Due to the conformal constraint, we have to neglect the old Lagrangian of dilatonic Born-Infeld theory and its black hole solutions, and introduce a new one. We obtain spherically symmetric nonlinearly charged black hole solutions in both Einstein and Jordan frames and then we calculate the related conserved and thermodynamic quantities. After that, we extend the phase space by considering the proportionality of the cosmological constant and thermodynamical pressure. We obtain critical values of the thermodynamic coordinates through numerical methods and plot the relevant P-V and G-T diagrams. Investigation of the mentioned diagrams helps us to study the thermodynamical phase transition. We also analyze the effects of varying different parameters on the phase transition of black holes. (orig.)
Simulated pressure denaturation thermodynamics of ubiquitin.
Ploetz, Elizabeth A; Smith, Paul E
2017-12-01
Simulations of protein thermodynamics are generally difficult to perform and provide limited information. It is desirable to increase the degree of detail provided by simulation and thereby the potential insight into the thermodynamic properties of proteins. In this study, we outline how to analyze simulation trajectories to decompose conformation-specific, parameter free, thermodynamically defined protein volumes into residue-based contributions. The total volumes are obtained using established methods from Fluctuation Solution Theory, while the volume decomposition is new and is performed using a simple proximity method. Native and fully extended ubiquitin are used as the test conformations. Changes in the protein volumes are then followed as a function of pressure, allowing for conformation-specific protein compressibility values to also be obtained. Residue volume and compressibility values indicate significant contributions to protein denaturation thermodynamics from nonpolar and coil residues, together with a general negative compressibility exhibited by acidic residues. Copyright © 2017 Elsevier B.V. All rights reserved.
A parametric model for the global thermodynamic behavior of fluids in the critical region
International Nuclear Information System (INIS)
Luettmer-Strathmann, J.; Tang, S.; Sengers, J.V.
1992-01-01
The asymptotic thermodynamic behavior of fluids near the critical point is described by scaling laws with universal scaling functions that can be represented by parametric equations. In this paper, we derive a more general parametric model that incorporates the crossover from singular thermodynamic behavior near the critical point to regular classical thermodynamic behavior far away from the critical point. Using ethane as an example, we show that such a parametric crossover model yields an accurate representation of the thermodynamic properties of fluids in a large region around the critical point
Thermodynamics of aqueous association and ionization reactions at high temperatures and pressures
International Nuclear Information System (INIS)
Mesmer, R.E.; Marshall, W.L.; Palmer, D.A.; Simonson, J.M.; Holmes, H.F.
1990-01-01
Electrochemical and electrical conductance cells have been widely used at ORNL over the years to quantitatively determine equilibrium constants and their salt effects to 300 degree C (EMF) and 800 degree C (conductance) at the saturation pressure of water (EMF) and to 4000 bars (conductance). The most precise results to 300 degree C for a large number of weak acids and bases show very similar thermodynamic behavior, which will be discussed. Results for the ionization constants of water, NH 3 (aq), HCl(aq), and NaCl(aq), which extend well into the supercritical region, have been fitted in terms of a model with dependence on density and temperature. The entropy change is found to be the driving force for ion-association reactions and this tendency increases (as it must) with increasing temperature at a given pressure. Also, the variation of all thermodynamic properties is greatly reduced at high fixed densities. Considerable variation occurs at low densities. From this analysis, the dependence of the reaction thermodynamics on the P-V-T properties of the solvent is shown, and the implication of large changes in hydration for solutes in the vicinity of the critical temperature will be discussed. Finally, the change in the molar compressibility coefficient for all reactions in water is shown to be the same and dependent only on the compressibility of the solvent
Thermodynamic inconsistency of the modified Saha equation at high pressures
International Nuclear Information System (INIS)
Sweeney, M.A.
1978-01-01
The inclusion of a pressure ionization term in the Saha equation violates the thermodynamic Maxwell identities if corresponding changes are not made to the expressions for entropy and pressure. It is demonstrated that the usual application of the Rouse and Stewart-Pyatt modesl suffers from this limitation. Negative values of the adiabatic gradient in the degenerate dwarf models of Boehm and Straka are explained in terms of this thermodynamic inconsistency
High-temperature of thermodynamic properties of sodium
Energy Technology Data Exchange (ETDEWEB)
Padilla, A. Jr.
1977-01-01
The set of high-temperature thermodynamic properties for sodium in the two-phase and subcooled-liquid regions which was previously recommended, has been modified to incorporate recent experimental data. In particular, replacement of the previously estimated critical constants with experimentally-determined values has resulted in substantial differences in the region of the critical point. The following thermodynamic properties were determined: pressure, density, enthalpy, entropy, internal energy, compressibility (adiabatic and isothermal), thermal expansion coefficient, thermal pressure coefficient, and specific heat (constant-pressure and constant-volume). These properties were determined for the saturated liquid, saturated vapor, subcooled liquid, and superheated vapor. The superheated vapor properties are limited to low pressures and more work is required to extend them to higher pressures. The supercritical region was not investigated.
Thermodynamics of Horndeski black holes with non-minimal derivative coupling
Energy Technology Data Exchange (ETDEWEB)
Miao, Yan-Gang [Nankai University, School of Physics, Tianjin (China); Max-Planck-Institut fuer Gravitationsphysik (Albert-Einstein-Institut), Potsdam (Germany); Xu, Zhen-Ming [Nankai University, School of Physics, Tianjin (China)
2016-11-15
We explore thermodynamic properties of a new class of Horndeski black holes whose action contains a non-minimal kinetic coupling of a massless real scalar and the Einstein tensor. Our treatment is based on the well-accepted consideration, where the cosmological constant is dealt with as thermodynamic pressure and the mass of black holes as thermodynamic enthalpy. We resort to a newly introduced intensive thermodynamic variable, i.e., the coupling strength of the scalar and tensor whose dimension is length square, and thus yield both the generalized first law of thermodynamics and the generalized Smarr relation. Our result indicates that this class of Horndeski black holes presents rich thermodynamic behaviors and critical phenomena. Especially in the case of the presence of an electric field, these black holes undergo two phase transitions. Once the charge parameter exceeds its critical value, or the cosmological parameter does not exceed its critical value, no phase transitions happen and the black holes are stable. As a by-product, we point out, the coupling strength acts as the thermodynamic pressure in thermodynamics. (orig.)
Thermodynamics of Horndeski black holes with non-minimal derivative coupling
International Nuclear Information System (INIS)
Miao, Yan-Gang; Xu, Zhen-Ming
2016-01-01
We explore thermodynamic properties of a new class of Horndeski black holes whose action contains a non-minimal kinetic coupling of a massless real scalar and the Einstein tensor. Our treatment is based on the well-accepted consideration, where the cosmological constant is dealt with as thermodynamic pressure and the mass of black holes as thermodynamic enthalpy. We resort to a newly introduced intensive thermodynamic variable, i.e., the coupling strength of the scalar and tensor whose dimension is length square, and thus yield both the generalized first law of thermodynamics and the generalized Smarr relation. Our result indicates that this class of Horndeski black holes presents rich thermodynamic behaviors and critical phenomena. Especially in the case of the presence of an electric field, these black holes undergo two phase transitions. Once the charge parameter exceeds its critical value, or the cosmological parameter does not exceed its critical value, no phase transitions happen and the black holes are stable. As a by-product, we point out, the coupling strength acts as the thermodynamic pressure in thermodynamics. (orig.)
International Nuclear Information System (INIS)
Chirico, R.D.; Steele, W.V.
2004-01-01
Measurements leading to the calculation of the standard thermodynamic properties for gaseous bicyclopentyl (Chemicals Abstracts registry number [1636-39-1]) are reported. Experimental methods include adiabatic heat-capacity calorimetry, comparative ebulliometry, and differential-scanning calorimetry (d.s.c.). The critical temperature was determined by d.s.c. and the critical pressure and critical density were estimated. Standard molar entropies, standard molar enthalpies, and standard molar Gibbs free energies of formation are reported at selected temperatures between T=(298.15 and 600) K. Formation properties were calculated with a literature value for the enthalpy of combustion in the liquid phase. All results are compared with available literature values
Thermodynamic properties by Equation of state of liquid sodium under pressure
Li, Huaming; Sun, Yongli; Zhang, Xiaoxiao; Li, Mo
Isothermal bulk modulus, molar volume and speed of sound of molten sodium are calculated through an equation of state of a power law form within good precision as compared with the experimental data. The calculated internal energy data show the minimum along the isothermal lines as the previous result but with slightly larger values. The calculated values of isobaric heat capacity show the unexpected minimum in the isothermal compression. The temperature and pressure derivative of various thermodynamic quantities in liquid Sodium are derived. It is discussed about the contribution from entropy to the temperature and pressure derivative of isothermal bulk modulus. The expressions for acoustical parameter and nonlinearity parameter are obtained based on thermodynamic relations from the equation of state. Both parameters for liquid Sodium are calculated under high pressure along the isothermal lines by using the available thermodynamic data and numeric derivations. By comparison with the results from experimental measurements and quasi-thermodynamic theory, the calculated values are found to be very close at melting point at ambient condition. Furthermore, several other thermodynamic quantities are also presented. Scientific Research Starting Foundation from Taiyuan university of Technology, Shanxi Provincial government (``100-talents program''), China Scholarship Council and National Natural Science Foundation of China (NSFC) under Grant No. 11204200.
Asymmetric fluid criticality. I. Scaling with pressure mixing.
Kim, Young C; Fisher, Michael E; Orkoulas, G
2003-06-01
The thermodynamic behavior of a fluid near a vapor-liquid and, hence, asymmetric critical point is discussed within a general "complete" scaling theory incorporating pressure mixing in the nonlinear scaling fields as well as corrections to scaling. This theory allows for a Yang-Yang anomaly in which mu(")(sigma)(T), the second temperature derivative of the chemical potential along the phase boundary, diverges like the specific heat when T-->T(c); it also generates a leading singular term, /t/(2beta), in the coexistence curve diameter, where t[triple bond](T-T(c))/T(c). The behavior of various special loci, such as the critical isochore, the critical isotherm, the k-inflection loci, on which chi((k))[triple bond]chi(rho,T)/rho(k) (with chi=rho(2)k(B)TK(T)) and C((k))(V)[triple bond]C(V)(rho,T)/rho(k) are maximal at fixed T, is carefully elucidated. These results are useful for analyzing simulations and experiments, since particular, nonuniversal values of k specify loci that approach the critical density most rapidly and reflect the pressure-mixing coefficient. Concrete illustrations are presented for the hard-core square-well fluid and for the restricted primitive model electrolyte. For comparison, a discussion of the classical (or Landau) theory is presented briefly and various interesting loci are determined explicitly and illustrated quantitatively for a van der Waals fluid.
Directory of Open Access Journals (Sweden)
Stuart P Wilson
2017-01-01
Full Text Available A thermodynamic model of thermoregulatory huddling interactions between endotherms is developed. The model is presented as a Monte Carlo algorithm in which animals are iteratively exchanged between groups, with a probability of exchanging groups defined in terms of the temperature of the environment and the body temperatures of the animals. The temperature-dependent exchange of animals between groups is shown to reproduce a second-order critical phase transition, i.e., a smooth switch to huddling when the environment gets colder, as measured in recent experiments. A peak in the rate at which group sizes change, referred to as pup flow, is predicted at the critical temperature of the phase transition, consistent with a thermodynamic description of huddling, and with a description of the huddle as a self-organising system. The model was subjected to a simple evolutionary procedure, by iteratively substituting the physiologies of individuals that fail to balance the costs of thermoregulation (by huddling in groups with the costs of thermogenesis (by contributing heat. The resulting tension between cooperative and competitive interactions was found to generate a phenomenon called self-organised criticality, as evidenced by the emergence of avalanches in fitness that propagate across many generations. The emergence of avalanches reveals how huddling can introduce correlations in fitness between individuals and thereby constrain evolutionary dynamics. Finally, a full agent-based model of huddling interactions is also shown to generate criticality when subjected to the same evolutionary pressures. The agent-based model is related to the Monte Carlo model in the way that a Vicsek model is related to an Ising model in statistical physics. Huddling therefore presents an opportunity to use thermodynamic theory to study an emergent adaptive animal behaviour. In more general terms, huddling is proposed as an ideal system for investigating the interaction
International Nuclear Information System (INIS)
Soldatova, Je.D.; Snegyir'ov, M.G.
2001-01-01
The thermodynamical method for studing a critical state is illustrated by the example of critical behavior of metallic cerium in the frameworks of the improved Rainford-Edwards model. Thermodynamical stability of the model is investigated, and behavior of the whole complex of thermodynamical characteristics of the system is analyzed. It is concluded that the model has the first type of critical behaviour
Critical pressure of non-equilibrium two-phase critical flow
Energy Technology Data Exchange (ETDEWEB)
Minzer, U [Israel Electric Corp. Ltd., Haifa (Israel)
1996-12-01
Critical pressure is defined as the pressure existing at the exit edge of the piping, when it remains constant despite a decrease in the back. According to this definition the critical pressure is larger than the back pressure and for two-phase conditions below saturation pressure. The two-phase critical pressure has a major influence on the two-phase critical flow characteristics. Therefore it is of High significance in calculations of critical mass flux and critical depressurization rate, which are important in the fields of Nuclear Reactor Safety and Industrial Safety. At the Nuclear Reactor Safety field is useful for estimations of the Reactor Cooling System depressurization, the core coolant level, and the pressure build-up in the containment. In the Industrial Safety field it is helpful for estimating the leakage rate of toxic gases Tom liquefied gas pressure vessels, depressurization of pressure vessels, and explosion conditions due to liquefied gas release. For physical description of non-equilibrium two-phase critical flow it would be convenient to divide the flow into two stages. The first stage is the flow of subcooled liquid at constant temperature and uniform pressure drop (i.e., the case of incompressible fluid and uniform piping cross section). The rapid flow of the liquid causes a delay in the boiling of the liquid, which begins to boil below saturation pressure, at thermal non-equilibrium. The boiling is the beginning of the second stage, characterized by a sharp increase of the pressure drop. The liquid temperature on the second stage is almost constant because most of the energy for vaporization is supplied from the large pressure drop The present work will focus on the two-phase critical pressure of water, since water serves as coolant in the vast majority of nuclear power reactors throughout the world. (author).
Critical pressure of non-equilibrium two-phase critical flow
International Nuclear Information System (INIS)
Minzer, U.
1996-01-01
Critical pressure is defined as the pressure existing at the exit edge of the piping, when it remains constant despite a decrease in the back. According to this definition the critical pressure is larger than the back pressure and for two-phase conditions below saturation pressure. The two-phase critical pressure has a major influence on the two-phase critical flow characteristics. Therefore it is of High significance in calculations of critical mass flux and critical depressurization rate, which are important in the fields of Nuclear Reactor Safety and Industrial Safety. At the Nuclear Reactor Safety field is useful for estimations of the Reactor Cooling System depressurization, the core coolant level, and the pressure build-up in the containment. In the Industrial Safety field it is helpful for estimating the leakage rate of toxic gases Tom liquefied gas pressure vessels, depressurization of pressure vessels, and explosion conditions due to liquefied gas release. For physical description of non-equilibrium two-phase critical flow it would be convenient to divide the flow into two stages. The first stage is the flow of subcooled liquid at constant temperature and uniform pressure drop (i.e., the case of incompressible fluid and uniform piping cross section). The rapid flow of the liquid causes a delay in the boiling of the liquid, which begins to boil below saturation pressure, at thermal non-equilibrium. The boiling is the beginning of the second stage, characterized by a sharp increase of the pressure drop. The liquid temperature on the second stage is almost constant because most of the energy for vaporization is supplied from the large pressure drop The present work will focus on the two-phase critical pressure of water, since water serves as coolant in the vast majority of nuclear power reactors throughout the world. (author)
International Nuclear Information System (INIS)
Elsner, Albrecht
2012-01-01
Gibbs's work on the thermodynamic properties of substances presented a complete thermodynamic theory. The formulations of the entropy S and internal energy U as extensive quantities allow the zeros of the real gas to be given: S=0 at absolute zero (Nernst, Planck) and U=0 at the critical point. Consequently, every thermodynamic function is unique and absolutely specified. Interdependences among quantities such as temperature, vapor pressure, chemical potential, volume, entropy, internal energy, and heat capacity are likewise unique and numerically well defined. This is shown for the saturated fluid, water, in the region between absolute zero and the critical point. As a consequence of the calculation of the chemical potential, it follows that the free particle flow in an inhomogeneous system is essentially governed by the difference in chemical potential, and not through the difference in pressure, this effect being of importance for meteorology and oceanography.
Thermodynamics of high-pressure ice polymorphs : ices III and V
Tchijov, [No Value; Ayala, RB; Leon, GC; Nagornov, O
Thermodynamic properties of high-pressure ice polymorphs, ices III and V, are studied theoretically. The results of TIP4P molecular dynamics simulations in the NPT ensemble are used to calculate the temperature dependence of the specific volume of ices III and V at pressures 0.25 and 0.5 GPa,
Thermodynamic properties of water in the critical region
International Nuclear Information System (INIS)
Veloso, Marcelo A.
2009-01-01
The supercritical-water-cooled reactor (SCWR) is one of the nuclear reactor technologies selected for research and development under the Generation IV program. SCWRs offer the potential for high thermal efficiencies and considerable plant simplifications for improved economics. One of the main characteristics of critical water is the strong variations of its thermal-physical properties in the vicinity of the critical point. These large variations may result in an unusual heat transfer behavior. The 1967 IFC Formulation for Industrial Use, which until 1998 formed the basis of steam tables used in many areas of steam power industry throughout the world since the late 1960's, has been now replaced with the IAPWS IF-97 Formulation for the Thermodynamic Properties of Water and Steam for Industrial Use, adopted by the International Association for the Properties of Water and Steam (IAPWS) in 1997. An IAPWS release points out that this new formulation has some unsatisfactory features in the immediate vicinity of the critical point. In order to investigate this singular aspect, which is crucial to better understand the heat transfer mechanism in a SCWR system, predictions by the IAPWS-IF97 formulation will be compared with thermodynamic properties values predicted by an alternative crossover equation of state as well as with experimental data found in literature. (author)
Communication: Thermodynamic analysis of critical conditions of polymer adsorption
International Nuclear Information System (INIS)
Cimino, R.; Neimark, A. V.; Rasmussen, C. J.
2013-01-01
Polymer adsorption to solid surfaces is a ubiquitous phenomenon, which has attracted long-lasting attention. Dependent on the competition between the polymer-solid adsorption and polymer-solvent solvation interactions, a chain may assume either 3d solvated conformation when adsorption is weak or 2d adsorbed conformation when adsorption is strong. The transition between these conformations occurring upon variation of adsorption strength is quite sharp, and in the limit of “infinite” chain length, can be treated as a critical phenomenon. We suggest a novel thermodynamic definition of the critical conditions of polymer adsorption from the equality of incremental chemical potentials of adsorbed and free chains. We show with the example of freely jointed Lennard-Jones chains tethered to an adsorbing surface that this new definition provides a link between thermodynamic and geometrical features of adsorbed chains and is in line with classical scaling relationships for the fraction of adsorbed monomers, chain radii of gyration, and free energy
Communication: Thermodynamic analysis of critical conditions of polymer adsorption
Energy Technology Data Exchange (ETDEWEB)
Cimino, R.; Neimark, A. V., E-mail: aneimark@rutgers.edu [Department of Chemical and Biochemical Engineering, Rutgers, The State University of New Jersey, 98 Brett Road, Piscataway, New Jersey 08854 (United States); Rasmussen, C. J. [DuPont Central Research and Development, Corporate Center for Analytical Sciences, Macromolecular Characterization, Route 141 and Henry Clay, Wilmington, Delaware 19803 (United States)
2013-11-28
Polymer adsorption to solid surfaces is a ubiquitous phenomenon, which has attracted long-lasting attention. Dependent on the competition between the polymer-solid adsorption and polymer-solvent solvation interactions, a chain may assume either 3d solvated conformation when adsorption is weak or 2d adsorbed conformation when adsorption is strong. The transition between these conformations occurring upon variation of adsorption strength is quite sharp, and in the limit of “infinite” chain length, can be treated as a critical phenomenon. We suggest a novel thermodynamic definition of the critical conditions of polymer adsorption from the equality of incremental chemical potentials of adsorbed and free chains. We show with the example of freely jointed Lennard-Jones chains tethered to an adsorbing surface that this new definition provides a link between thermodynamic and geometrical features of adsorbed chains and is in line with classical scaling relationships for the fraction of adsorbed monomers, chain radii of gyration, and free energy.
International thermodynamic tables of the fluid state helium-4
de Reuck, K M; McCarty, R D
2013-01-01
International Thermodynamic Tables of the Fluid State Helium-4 presents the IUPAC Thermodynamic Tables for the thermodynamic properties of helium. The IUPAC Thermodynamic Tables Project has therefore encouraged the critical analysis of the available thermodynamic measurements for helium and their synthesis into tables. This book is divided into three chapters. The first chapter discusses the experimental results and compares with the equations used to generate the tables. These equations are supplemented by a vapor pressure equation, which represents the 1958 He-4 scale of temperature that is
Discerning Thermodynamic Basis of Self-Organization in Critical Zone Structure and Function
Richardson, M.; Kumar, P.
2017-12-01
Self-organization characterizes the spontaneous emergence of order. Self-organization in the Critical Zone, the region of Earth's skin from below the groundwater table to the top of the vegetation canopy, involves the interaction of biotic and abiotic processes occurring through a hierarchy of temporal and spatial scales. The self-organization is sustained through input of energy and material in an open system framework, and the resulting formations are called dissipative structures. Why do these local states of organization form and how are they thermodynamically favorable? We hypothesize that structure formation is linked to energy conversion and matter throughput rates across driving gradients. Furthermore, we predict that structures in the Critical Zone evolve based on local availability of nutrients, water, and energy. By considering ecosystems as open thermodynamic systems, we model and study the throughput signatures on short times scales to determine origins and characteristics of ecosystem structure. This diagnostic approach allows us to use fluxes of matter and energy to understand the thermodynamic drivers of the system. By classifying the fluxes and dynamics in a system, we can identify patterns to determine the thermodynamic drivers for organized states. Additionally, studying the partitioning of nutrients, water, and energy throughout ecosystems through dissipative structures will help identify reasons for structure shapes and how these shapes impact major Critical Zone functions.
Application of calorimetry and thermodynamics to critical problems in materials science
International Nuclear Information System (INIS)
Atake, Tooru
2009-01-01
Calorimetry and thermodynamic studies have long been playing a very important role in the research fields of fundamental science and technology. Some topics and examples of thermodynamics studies are given, and the details are explained on the basis of the present author's experience, focusing attention to application of adiabatic calorimetry and thermodynamics to solve critical problems in materials science: (1) condensed gas calorimetry and third law entropy, (2) phase transition and polymorphism in simple molecular crystals, (3) incommensurate phase transitions, (4) particle size effects on the phase transitions in ferroelectric/ferroelastic crystals, (5) relaxor ferroelectrics and multi-ferroics, and some other topics in materials science and technology
Computer codes used in the calculation of high-temperature thermodynamic properties of sodium
International Nuclear Information System (INIS)
Fink, J.K.
1979-12-01
Three computer codes - SODIPROP, NAVAPOR, and NASUPER - were written in order to calculate a self-consistent set of thermodynamic properties for saturated, subcooled, and superheated sodium. These calculations incorporate new critical parameters (temperature, pressure, and density) and recently derived single equations for enthalpy and vapor pressure. The following thermodynamic properties have been calculated in these codes: enthalpy, heat capacity, entropy, vapor pressure, heat of vaporization, density, volumetric thermal expansion coefficient, compressibility, and thermal pressure coefficient. In the code SODIPROP, these properties are calculated for saturated and subcooled liquid sodium. Thermodynamic properties of saturated sodium vapor are calculated in the code NAVAPOR. The code NASUPER calculates thermodynamic properties for super-heated sodium vapor only for low (< 1644 K) temperatures. No calculations were made for the supercritical region
International Nuclear Information System (INIS)
Chun, Se-Y.; Shin, C.W.; Hong, S. D.; Moon, S. K.
2007-01-01
A supercritical-pressure light water reactor (SCWR) is currently investigated as the next generation nuclear reactors. The SCWR, which is operated above the thermodynamic critical point of water (647 K, 22.1 MPa), have advantages over conventional light water reactors in terms of thermal efficiency as well as in compactness and simplicity. Many experimental studies have been performed on heat transfer in the boiler tubes of supercritical fossil fire power plants (FPPs). However, the thermal-hydraulic conditions of the SCWR core are different from those of the FPP boiler. In the SCWR core, the heat transfer to the cooling water occurs on the outside surface of fuel rods in rod bundle with spacers. In addition, the experimental studies in which the critical heat flux (CHF) has been carefully measured near the critical pressure have never yet been carried out, as far as we know. Therefore, we have recently conducted the CHF experiments with a vertical 5x5 heater rod bundle cooled by R- 134a fluid. The purpose of this work is to find out some novel knowledge for the CHF near the critical pressure, based on more careful experiments. The outer diameter, heated length and rod pitch of the heater rods are 9.5, 2000 and 12.85 mm, respectively. The critical power has been measured in a range of the pressure of 2.474.03 MPa (the critical pressure of R-134a is 4.059 MPa), the mass flux 502000 kg/m 2 s, and the inlet subcooling 4084 kJ/kg. For the mass fluxes of not less than 550 kg/m 2 s, the critical power decreases monotonously up to the pressure of about 3.63.8 MPa with increasing pressure, and then fall sharply at about 3.83.9 MPa as if the values of the critical power converge on zero at the critical pressure. For the low mass fluxes of 50 to 250 kg/m 2 , the sharp decreasing trend of the critical power near the critical pressure is not observed. The CHF phenomenon near the critical pressure no longer leads to an inordinate increase in the heated wall temperature such as
Experimental thermodynamics experimental thermodynamics of non-reacting fluids
Neindre, B Le
2013-01-01
Experimental Thermodynamics, Volume II: Experimental Thermodynamics of Non-reacting Fluids focuses on experimental methods and procedures in the study of thermophysical properties of fluids. The selection first offers information on methods used in measuring thermodynamic properties and tests, including physical quantities and symbols for physical quantities, thermodynamic definitions, and definition of activities and related quantities. The text also describes reference materials for thermometric fixed points, temperature measurement under pressures, and pressure measurements. The publicatio
Thermodynamic and transport properties of sodium liquid and vapor
International Nuclear Information System (INIS)
Fink, J.K.; Leibowitz, L.
1995-01-01
Data have been reviewed to obtain thermodynamically consistent equations for thermodynamic and transport properties of saturated sodium liquid and vapor. Recently published Russian recommendations and results of equation of state calculations on thermophysical properties of sodium have been included in this critical assessment. Thermodynamic properties of sodium liquid and vapor that have been assessed include: enthalpy, heat capacity at constant pressure, heat capacity at constant volume, vapor pressure, boiling point, enthalpy of vaporization, density, thermal expansion, adiabatic and isothermal compressibility, speed of sound, critical parameters, and surface tension. Transport properties of liquid sodium that have been assessed include: viscosity and thermal conductivity. For each property, recommended values and their uncertainties are graphed and tabulated as functions of temperature. Detailed discussions of the analyses and determinations of the recommended equations include comparisons with recommendations given in other assessments and explanations of consistency requirements. The rationale and methods used in determining the uncertainties in the recommended values are also discussed
A low pressure thermodynamic cycle for electric power generation without mechanical compressor
International Nuclear Information System (INIS)
Proto, G.; Lenti, R.
1996-01-01
According to the 2 nd thermodynamic law there is no compulsion to have an expansion from high pressure level to atmospheric pressure, the only reason relying upon the minimization of the plant volumetry which is just one of the overall cost parameters. A thermodynamic cycle without rotating machinery does exist in avionic applications like the RAMJET, in which air flowing at supersonic speed is compressed in a convergent duct before being heated in the combustion chamber and then expanded to a much higher MACH number. The concept discussed here, however, is referred to a physical principle of different nature. In fact the inlet air flow is quasi static, while the propelling kinetic energy is the residual energy following the gas combustion, expansion, cooling in Supersonic Flow and ultimately its fluidic compression in a convergent duct. The concept theoretically relies upon the so called 'Simple T 0 change' transformation, according to which, in a Supersonic Flow at constant cross section and without mechanical dissipation, a decrease in the gas stagnation temperature (T 0 ) will turn into an increase of its stagnation pressure. The paper discusses the feasibility of such a process, focusing on a specific conceptual application to a subatmospheric pressure, high temperature Brayton cycle getting to the conclusion that, even with the materials technology limitations, there is the potential for significant improvement of the actual thermodynamic cycle efficiency. (author). 6 figs.,1 tab., 2 refs
Thermodynamic functions and vapor pressures of uranium and plutonium oxides at high temperatures
International Nuclear Information System (INIS)
Green, D.W.; Reedy, G.T.; Leibowitz, L.
1977-01-01
The total energy release in a hypothetical reactor accident is sensitive to the total vapor pressure of the fuel. Thermodynamic functions which are accurate at high temperature can be calculated with the methods of statistical mechanics provided that needed spectroscopic data are available. This method of obtaining high-temperature vapor pressures should be greatly superior to the extrapolation of experimental vapor pressure measurements beyond the temperature range studied. Spectroscopic data needed for these calculations are obtained from infrared spectroscopy of matrix-isolated uranium and plutonium oxides. These data allow the assignments of the observed spectra to specific molecular species as well as the calculation of anharmonicities for monoxides, bond angles for dioxides, and molecular geometries for trioxides. These data are then employed, in combination with data on rotational and electronic molecular energy levels, to determine thermodynamic functions that are suitable for the calculation of high-temperature vapor pressures
Thermodynamic Fluid Equations-of-State
Directory of Open Access Journals (Sweden)
Leslie V. Woodcock
2018-01-01
Full Text Available As experimental measurements of thermodynamic properties have improved in accuracy, to five or six figures, over the decades, cubic equations that are widely used for modern thermodynamic fluid property data banks require ever-increasing numbers of terms with more fitted parameters. Functional forms with continuity for Gibbs density surface ρ(p,T which accommodate a critical-point singularity are fundamentally inappropriate in the vicinity of the critical temperature (Tc and pressure (pc and in the supercritical density mid-range between gas- and liquid-like states. A mesophase, confined within percolation transition loci that bound the gas- and liquid-state by third-order discontinuities in derivatives of the Gibbs energy, has been identified. There is no critical-point singularity at Tc on Gibbs density surface and no continuity of gas and liquid. When appropriate functional forms are used for each state separately, we find that the mesophase pressure functions are linear. The negative and positive deviations, for both gas and liquid states, on either side of the mesophase, are accurately represented by three or four-term virial expansions. All gaseous states require only known virial coefficients, and physical constants belonging to the fluid, i.e., Boyle temperature (TB, critical temperature (Tc, critical pressure (pc and coexisting densities of gas (ρcG and liquid (ρcL along the critical isotherm. A notable finding for simple fluids is that for all gaseous states below TB, the contribution of the fourth virial term is negligible within experimental uncertainty. Use may be made of a symmetry between gas and liquid states in the state function rigidity (dp/dρT to specify lower-order liquid-state coefficients. Preliminary results for selected isotherms and isochores are presented for the exemplary fluids, CO2, argon, water and SF6, with focus on the supercritical mesophase and critical region.
Behavior of the Thermodynamic Properties of Binary Mixtures near the Critical Azeotrope
Directory of Open Access Journals (Sweden)
Azzedine Abbaci
2003-12-01
Full Text Available Abstract: In this work we investigate the critical line of binary azeotropic mixtures of acetone-n-pentane. We pinpoint the abnormal behavior of the critical density line as a function of the mole fraction of one of the component and show its influence on other thermodynamic properties such as the volume, the enthalpy and the entropy.
Temperature and pressure dependent thermodynamic behavior of 2H-CuInO2
Bhamu, K. C.
2018-05-01
Density functional theory and quasi-harmonic Debye model has been used to study the thermodynamic properties of 2H-CuInO2. At the optimized structural parameters, pressure (0 to 80 GPa) dependent variation in the various thermodynamic properties, i.e. unit cell volume (V), bulk modulus (B), specific heat (Cv), Debye temperature (θD), Grüneisen parameter (γ) and thermal expansion coefficient (α) are calculated for various temperature values. The results predict that the pressure has significant effect on unit cell volume and bulk modulus while the temperature shows negligible effect on both parameters. With increasing temperature thermal expansion coefficient increase while with increasing pressure it decreases. The specific heat remains close to zero for ambient pressure and temperature values and it increases with increasing temperature. It is observed that the pressure has high impact on Debye temperature and Grüneisen parameter instead of temperature. Debye temperature and Grüneisen parameter both remains almost constant for the temperature range (0-300K) while Grüneisen parameter decrease with increasing pressure at constant temperature and Debye temperature increases rapidly with increasing pressure. An increase in Debye temperature with respect to pressure shows that the thermal vibration frequency changes rapidly.
Thermodynamic understanding on swelling pressure of bentonite buffer
International Nuclear Information System (INIS)
Sato, Haruo
2007-01-01
Smectite (montmorillonite) is a major clay mineral constituent of the bentonite buffer and backfilling materials to be used for the geological disposal of high-level radioactive waste. Swelling pressure of the bentonite buffer occurring in the permeation process of moisture was estimated based on thermodynamic theory and the thermodynamic data of interlayer water in smectite in this study. The relative partial molar Gibbs free energies (ΔG H2O ) of water on the smectite surface were measured as a function of water content (0-83%) in a dry density range of 0.6-0.9 Mg/m 3 . Purified Na-smectite of which interlayer cations were exchanged with Na + ions and soluble salts were completely removed, was used in this study. Obtained ΔG H2O decreased with an increase of water content in the range of water content lower than about 40%, and similar trends were obtained to data of Kunipia-F bentonite (Na-bentonite) of which smectite content was approximately 100 wt.%. From the specific surface area of smectite (ca. 800 m 2 /g) and the correlation between ΔG H2O and water content, water affected from the surface of smectite was estimated to be up to approximately 2 water layers. Swelling pressure versus smectite partial density (montmorillonite partial density) was estimated based on ΔG H2O from the chemical potential balance of water in equilibrium between the free water and moisturized smectite, and compared to data measured for various kinds of bentonites of which smectite contents were respectively different. The estimated swelling pressures were in good agreement with the measured data. (author)
International Nuclear Information System (INIS)
Kim, Junghwan; Jung, In-Ho
2012-01-01
Highlights: ► The Mn–RE (RE = La, Ce, Pr, Nd and Sm) systems have been critically reviewed. ► The thermodynamic optimization of the Mn–RE systems have been performed. ► Systematic changes in the phase diagrams and thermodynamic properties were found. ► The systematic approach resolved inconsistencies in the experimental data. - Abstract: Critical evaluation and optimization of all available phase diagram and thermodynamic data for the Mn–RE (RE = La, Ce, Pr, Nd and Sm) systems have been conducted to obtain reliable thermodynamic functions of all the phases in the system. In the thermodynamic modeling, it is found that the Mn–RE systems show systematic changes in the phase diagrams and thermodynamic properties such as enthalpy of mixing in liquid state in the order of periodic number in the lanthanide series. This systematic thermodynamic modeling approach for all light RE elements can allow to resolve inconsistencies in the experimental data.
Kinetic and thermodynamic analysis of ultra-high pressure and heat ...
African Journals Online (AJOL)
Purpose: To undertake comparative kinetic and thermodynamic analyses of the interaction of bovine serum albumin (BSA) with IgG pre-treated with ultra-high pressure (UHP) and moderate heat. Methods: BSA solutions were processed at 100 – 600 MPa and 25 – 40 °C. We applied an optical biosensor based on surface ...
Critical evaluation and thermodynamic optimization of the U-Pb and U-Sb binary systems
International Nuclear Information System (INIS)
Wang, Jian; Jin, Liling; Chen, Chuchu; Rao, Weifeng; Wang, Cuiping; Liu, Xingjun
2016-01-01
A complete literature review, critical evaluation and thermodynamic optimization of the phase diagrams and thermodynamic properties of U-Pb and U-Sb binary systems are presented. The CALculation of PHAse Diagrams (CALPHAD) method was used for the thermodynamic optimization, the results of which can reproduce all available reliable experimental phase equilibria and thermodynamic data. The modified quasi-chemical model in the pair approximation (MQMPA) was used for modeling the liquid solution. The Gibbs energies of all terminal solid solutions and intermetallic compounds were described by the compound energy formalism (CEF) model. All reliable experimental data of the U-Pb and U-Sb systems have been reproduced. A self-consistent thermodynamic database has been constructed for these binary systems; this database can be used in liquid-metal fuel reactor (LMFR) research.
Superconducting critical temperature under pressure
González-Pedreros, G. I.; Baquero, R.
2018-05-01
The present record on the critical temperature of a superconductor is held by sulfur hydride (approx. 200 K) under very high pressure (approx. 56 GPa.). As a consequence, the dependence of the superconducting critical temperature on pressure became a subject of great interest and a high number of papers on of different aspects of this subject have been published in the scientific literature since. In this paper, we calculate the superconducting critical temperature as a function of pressure, Tc(P), by a simple method. Our method is based on the functional derivative of the critical temperature with the Eliashberg function, δTc(P)/δα2F(ω). We obtain the needed coulomb electron-electron repulsion parameter, μ*(P) at each pressure in a consistent way by fitting it to the corresponding Tc using the linearized Migdal-Eliashberg equation. This method requires as input the knowledge of Tc at the starting pressure only. It applies to superconductors for which the Migdal-Eliashberg equations hold. We study Al and β - Sn two weak-coupling low-Tc superconductors and Nb, the strong coupling element with the highest critical temperature. For Al, our results for Tc(P) show an excellent agreement with the calculations of Profeta et al. which are known to agree well with experiment. For β - Sn and Nb, we found a good agreement with the experimental measurements reported in several works. This method has also been applied successfully to PdH elsewhere. Our method is simple, computationally light and gives very accurate results.
Thermodynamic relations in high temperature and high pressure physics of solids
International Nuclear Information System (INIS)
Kumar, Munish
1998-01-01
Various possible simple relations based on the exact and approximate thermodynamic relations are derived. These relations can be used to investigate the variation of unit cell volume under the effect of pressure and temperature. Thermal expansivity and compressibility can be investigated directly at any pressure or temperature, or through the knowledge of equation of state (EOS). A relation to determine Anderson-Grueneisen parameter δ T under the effect of pressure is predicted. It is discussed that δ T is independent of pressure and thus Murnaghan equation of state works well in low pressure ranges, while the variation of δ T under high pressure should be taken into account. The product of coefficient of volume thermal expansion and bulk modulus remains constant, is correct at high pressure, provided that the pressure dependence of δ T is considered. (author)
On the thermodynamic stability of the generalized Chaplygin gas
International Nuclear Information System (INIS)
Santos, F.C.; Bedran, M.L.; Soares, V.
2006-01-01
The main purpose of this Letter is to discuss the temperature behavior and the thermodynamic stability of an exotic fluid known as generalized Chaplygin gas considering only general thermodynamics. This fluid is considered a perfect fluid which obeys an adiabatic equation of state like P=-A/ρ α , where P and ρ are respectively the pressure and energy density; the parameter A is a positive universal constant and α>0. It is remarked that if the energy density of the fluid is a function of volume only, the temperature of the fluid remains zero at any pressure or volume, violating the third law of thermodynamics. We have determined a scenario where its thermal equation of state depends on temperature only and the fluid presents thermodynamic stability during any expansion process. Such a scenario also reveals that the fluid cools down through the expansion without facing any critical point or phase transition
Pressure effect on structural, elastic, and thermodynamic properties of tetragonal B4C4
Directory of Open Access Journals (Sweden)
Baobing Zheng
2015-03-01
Full Text Available The compressibility, elastic anisotropy, and thermodynamic properties of the recently proposed tetragonal B4C4 (t-B4C4 are investigated under high temperature and high pressure by using of first-principles calculations method. The elastic constants, bulk modulus, shear modulus, Young’s modulus, Vickers hardness, Pugh’s modulus ratio, and Poisson’s ratio for t-B4C4 under various pressures are systematically explored, the obtained results indicate that t-B4C4 is a stiffer material. The elastic anisotropies of t-B4C4 are discussed in detail under pressure from 0 GPa to 100 GPa. The thermodynamic properties of t-B4C4, such as Debye temperature, heat capacity, and thermal expansion coefficient are investigated by the quasi-harmonic Debye model.
International Nuclear Information System (INIS)
Matsui, T.; Ohse, R.W.
1986-01-01
Thermodynamic properties such as vapour pressures, heat capacities and enthalpies of formation for UN(s), PuN(s) and (U, Pu)N(s) are critically evaluated. The equations of the vapour pressures and the heat capacities for the three nitrides are assessed. Thermal functions, and thermodynamic functions for the formation of UN(s), PuN(s) and (U, Pu)N(s), are calculated
Thermodynamic analysis of transition pressure of δ-stabilized binary plutonium alloys
International Nuclear Information System (INIS)
Wang Qinghui
1992-01-01
The transformation of δ-stabilized binary plutonium alloys to α-Pu was studies by thermodynamic analysis. A transition pressure-composition equation which can characterize the high pressure transformation from δ to α was derived. Values calculated by the equation and values measured by experiments of published references have the same tendency. the following facts can be explained properly by this equation. (1)The transformation pressure increases linearly with the amount of an alloying element. (2) The slope of the plot of transformation pressure versus composition of δ-Pu alloys is inversely proportional to the minimum amount of solute required to retain δ-phase at room temperature and pressure. (3) Curves showing the relationship between transformation pressure and composition of various δ-stabilized binary alloys interact at the same point of zero solute (transformation pressure axis). In addition, some transformation pressures from δ to α of δ-stabilized alloys are predicted by using the modified theoretical equation
Directory of Open Access Journals (Sweden)
Bidai K.
2017-06-01
Full Text Available First-principles density functional theory calculations have been performed to investigate the structural, elastic and thermodynamic properties of rubidium telluride in cubic anti-fluorite (anti-CaF2-type structure. The calculated ground-state properties of Rb2Te compound such as equilibrium lattice parameter and bulk moduli are investigated by generalized gradient approximation (GGA-PBE that are based on the optimization of total energy. The elastic constants, Young’s and shear modulus, Poisson ratio, have also been calculated. Our results are in reasonable agreement with the available theoretical and experimental data. The pressure dependence of elastic constant and thermodynamic quantities under high pressure are also calculated and discussed.
Yip, Ngai Yin; Elimelech, Menachem
2012-05-01
The Gibbs free energy of mixing dissipated when fresh river water flows into the sea can be harnessed for sustainable power generation. Pressure retarded osmosis (PRO) is one of the methods proposed to generate power from natural salinity gradients. In this study, we carry out a thermodynamic and energy efficiency analysis of PRO work extraction. First, we present a reversible thermodynamic model for PRO and verify that the theoretical maximum extractable work in a reversible PRO process is identical to the Gibbs free energy of mixing. Work extraction in an irreversible constant-pressure PRO process is then examined. We derive an expression for the maximum extractable work in a constant-pressure PRO process and show that it is less than the ideal work (i.e., Gibbs free energy of mixing) due to inefficiencies intrinsic to the process. These inherent inefficiencies are attributed to (i) frictional losses required to overcome hydraulic resistance and drive water permeation and (ii) unutilized energy due to the discontinuation of water permeation when the osmotic pressure difference becomes equal to the applied hydraulic pressure. The highest extractable work in constant-pressure PRO with a seawater draw solution and river water feed solution is 0.75 kWh/m(3) while the free energy of mixing is 0.81 kWh/m(3)-a thermodynamic extraction efficiency of 91.1%. Our analysis further reveals that the operational objective to achieve high power density in a practical PRO process is inconsistent with the goal of maximum energy extraction. This study demonstrates thermodynamic and energetic approaches for PRO and offers insights on actual energy accessible for utilization in PRO power generation through salinity gradients. © 2012 American Chemical Society
Hess, Julian; Wang, Yongqi
2016-11-01
A new mixture model for granular-fluid flows, which is thermodynamically consistent with the entropy principle, is presented. The extra pore pressure described by a pressure diffusion equation and the hypoplastic material behavior obeying a transport equation are taken into account. The model is applied to granular-fluid flows, using a closing assumption in conjunction with the dynamic fluid pressure to describe the pressure-like residual unknowns, hereby overcoming previous uncertainties in the modeling process. Besides the thermodynamically consistent modeling, numerical simulations are carried out and demonstrate physically reasonable results, including simple shear flow in order to investigate the vertical distribution of the physical quantities, and a mixture flow down an inclined plane by means of the depth-integrated model. Results presented give insight in the ability of the deduced model to capture the key characteristics of granular-fluid flows. We acknowledge the support of the Deutsche Forschungsgemeinschaft (DFG) for this work within the Project Number WA 2610/3-1.
Low-temperature behaviour of an ideal Bose gas and some forbidden thermodynamic cycles
International Nuclear Information System (INIS)
Chen Jincan; Lin Bihong
2003-01-01
Based on the equation of state of an ideal Bose gas, the heat capacities at constant volume and constant pressure of the Bose system are derived and used to analyse the low-temperature behaviour of the Bose system. It is expounded that some important thermodynamic processes such as a constant pressure and an adiabatic process cannot be carried out from the region of T > T c to that of T c , where T c is the critical temperature of Bose-Einstein condensation of the Bose system. Consequently, some typical thermodynamic cycles such as the Carnot cycle, Brayton cycle, Otto cycle, Ericsson cycle, Diesel cycle and Atkinson cycle cannot be operated across the critical temperature T c of Bose-Einstein condensation of an ideal Bose gas
The critical roles of information and nonequilibrium thermodynamics in evolution of living systems.
Gatenby, Robert A; Frieden, B Roy
2013-04-01
Living cells are spatially bounded, low entropy systems that, although far from thermodynamic equilibrium, have persisted for billions of years. Schrödinger, Prigogine, and others explored the physical principles of living systems primarily in terms of the thermodynamics of order, energy, and entropy. This provided valuable insights, but not a comprehensive model. We propose the first principles of living systems must include: (1) Information dynamics, which permits conversion of energy to order through synthesis of specific and reproducible, structurally-ordered components; and (2) Nonequilibrium thermodynamics, which generate Darwinian forces that optimize the system.Living systems are fundamentally unstable because they exist far from thermodynamic equilibrium, but this apparently precarious state allows critical response that includes: (1) Feedback so that loss of order due to environmental perturbations generate information that initiates a corresponding response to restore baseline state. (2) Death due to a return to thermodynamic equilibrium to rapidly eliminate systems that cannot maintain order in local conditions. (3) Mitosis that rewards very successful systems, even when they attain order that is too high to be sustainable by environmental energy, by dividing so that each daughter cell has a much smaller energy requirement. Thus, nonequilibrium thermodynamics are ultimately responsible for Darwinian forces that optimize system dynamics, conferring robustness sufficient to allow continuous existence of living systems over billions of years.
From tricritical Ising to critical Ising by thermodynamic Bethe ansatz
International Nuclear Information System (INIS)
Zamolodchikov, A.B.
1991-01-01
A simple factorized scattering theory is suggested for the massless Goldstone fermions of the trajectory flowing from the tricritical Ising fixed point to the critical Ising one. The thermodynamic Bethe ansatz approach is applied to this scattering theory to support its interpretation both analytically and numerically. As a generalization a sequence of massless TBA systems is proposed which seems relevant for the trajectories interpolating between two successive minimal CFT models M p and M p-1 . (orig.)
Multi-pressure boiler thermodynamics analysis code
International Nuclear Information System (INIS)
Lorenzoni, G.
1992-01-01
A new method and the relative FORTRAN program for the thermodynamics design analysis of a multipressure boiler are reported. This method permits the thermodynamics design optimization with regard to total exergy production and a preliminary costs
International Nuclear Information System (INIS)
Zhang Xiao-Lin; Wu Yuan-Yuan; Shao Xiao-Hong; Lu Yong; Zhang Ping
2016-01-01
The high pressure behaviors of Th 4 H 15 and ThH 2 are investigated by using the first-principles calculations based on the density functional theory (DFT). From the energy–volume relations, the bct phase of ThH 2 is more stable than the fcc phase at ambient conditions. At high pressure, the bct ThH 2 and bcc Th 4 H 15 phases are more brittle than they are at ambient pressure from the calculated elastic constants and the Poisson ratio. The thermodynamic stability of the bct phase ThH 2 is determined from the calculated phonon dispersion. In the pressure domain of interest, the phonon dispersions of bcc Th 4 H 15 and bct ThH 2 are positive, indicating the dynamical stability of these two phases, while the fcc ThH 2 is unstable. The thermodynamic properties including the lattice vibration energy, entropy, and specific heat are predicted for these stable phases. The vibrational free energy decreases with the increase of the temperature, and the entropy and the heat capacity are proportional to the temperature and inversely proportional to the pressure. As the pressure increases, the resistance to the external pressure is strengthened for Th 4 H 15 and ThH 2 . (paper)
Towards a thermodynamics of active matter.
Takatori, S C; Brady, J F
2015-03-01
Self-propulsion allows living systems to display self-organization and unusual phase behavior. Unlike passive systems in thermal equilibrium, active matter systems are not constrained by conventional thermodynamic laws. A question arises, however, as to what extent, if any, can concepts from classical thermodynamics be applied to nonequilibrium systems like active matter. Here we use the new swim pressure perspective to develop a simple theory for predicting phase separation in active matter. Using purely mechanical arguments we generate a phase diagram with a spinodal and critical point, and define a nonequilibrium chemical potential to interpret the "binodal." We provide a generalization of thermodynamic concepts like the free energy and temperature for nonequilibrium active systems. Our theory agrees with existing simulation data both qualitatively and quantitatively and may provide a framework for understanding and predicting the behavior of nonequilibrium active systems.
Energy Technology Data Exchange (ETDEWEB)
Kang, Yeon Moon; Lee, D. J.; Yoon, J. H.; Kim, J. P.; Kim, H. Y
1999-03-01
At a critical flow condition, the flow rate can't exceed a maximum value for given upstream conditions and the limited flow rate is called as a critical flow rate. The phenomena of critical flow occur at the discharge of a single phase gas or subcooled water through nozzles and pipes. Among the previous researches on critical flow, many accurate correlations on pressure, temperature and flow rate are represented for the single phase gas. However, for the two phase critical flow, the results of previous work showed that there was a large discrepancy between the analytical and experimental data and the data were in agreement for the limited thermodynamic conditions. Thus, further studies are required to enhance the two phase critical flow model. In the integral reactor, the critical flows of nitrogen gas and subcooled water are expected for the break of gas cylinder pipeline connected to the pressurizer. It requires that the inlet shape of the pipe and the nitrogen gas effect should be considered for the critical flow of integral reactor. The nitrogen gas exist in the pressurizer may affect the flow rate of primary coolant, which has been considered only for a few previous researches. Thus, the evaluation of the effect of the nitrogen on the critical flow gas should be preceded for the proper analysis of the critical flow in the integral reactor. In this report, not only the essences of previous work on critical flow were investigated and summarized but also the effect of nitrogen gas and the inlet shape of the pipe on the critical flow were also investigated. (author)
International Nuclear Information System (INIS)
Kang, Yeon Moon; Lee, D. J.; Yoon, J. H.; Kim, J. P.; Kim, H. Y.
1999-03-01
At a critical flow condition, the flow rate can't exceed a maximum value for given upstream conditions and the limited flow rate is called as a critical flow rate. The phenomena of critical flow occur at the discharge of a single phase gas or subcooled water through nozzles and pipes. Among the previous researches on critical flow, many accurate correlations on pressure, temperature and flow rate are represented for the single phase gas. However, for the two phase critical flow, the results of previous work showed that there was a large discrepancy between the analytical and experimental data and the data were in agreement for the limited thermodynamic conditions. Thus, further studies are required to enhance the two phase critical flow model. In the integral reactor, the critical flows of nitrogen gas and subcooled water are expected for the break of gas cylinder pipeline connected to the pressurizer. It requires that the inlet shape of the pipe and the nitrogen gas effect should be considered for the critical flow of integral reactor. The nitrogen gas exist in the pressurizer may affect the flow rate of primary coolant, which has been considered only for a few previous researches. Thus, the evaluation of the effect of the nitrogen on the critical flow gas should be preceded for the proper analysis of the critical flow in the integral reactor. In this report, not only the essences of previous work on critical flow were investigated and summarized but also the effect of nitrogen gas and the inlet shape of the pipe on the critical flow were also investigated. (author)
Critical thermodynamic evaluation and optimization of the Fe–B, Fe–Nd, B–Nd and Nd–Fe–B systems
International Nuclear Information System (INIS)
Van Ende, Marie-Aline; Jung, In-Ho
2013-01-01
Highlights: ► Complete critical evaluation of all available phase diagram and thermodynamic data for the Fe–Nd–B system for the first time. ► Thermodynamic database of optimized model parameters has been developed. ► Gibbs energies of binary and ternary solid and liquid phases were properly described. ► All reliable thermodynamic and phase diagram data were properly reproduced. ► Liquidus projection of the Fe–Nd–B system is properly predicted for the first time. - Abstract: All experimental data on phase equilibria and thermodynamic properties of the Fe–B, Fe–Nd and Nd–B binary and Fe–Nd–B ternary systems in literature were reviewed and critically examined. A set of optimized model parameters for all solid stoichiometric compounds, solid solutions and liquid phase was built to reproduce all available reliable thermodynamic properties and phase diagram data within experimental error limits. The solid solutions were modeled using the Compound Energy Formalism. The Modified Quasichemical Model in the pair approximation was used to describe the thermodynamic properties of the liquid solution accurately. The database of the model parameters can be used, along with the software for Gibbs energy minimization, to calculate any type of phase diagram section. Unexplored liquidus projection of the Fe–Nd–B ternary system was predicted from the thermodynamic models and optimized parameters.
Thermodynamic properties of the liquid Hg-Tl alloys determined from vapour pressure measurements
Directory of Open Access Journals (Sweden)
Gierlotka W.
2002-01-01
Full Text Available The partial vapour pressure of mercury over liquid Hg-Tl liquid solutions were determined in the temperature range from 450 to 700 K by direct vapour pressure measurements carried out with the quartz gauge. From the measured ln pHg vs. T relationships activities of mercury were determined. Using Redlich-Kister formulas logarithms of the activity coefficients were described with the following equations: From which all thermodynamic functions in the solutions can be derived.
Thermodynamic properties of OsB under high temperature and high pressure
Chen, Hai-Hua; Li, Zuo; Cheng, Yan; Bi, Yan; Cai, Ling-Cang
2011-09-01
The energy-volume curves of OsB have been obtained using the first-principles plane-wave ultrasoft-pseudopotential density functional theory (DFT) within the generalized gradient approximation (GGA) and local density approximation (LDA). Using the quasi-harmonic Debye model we first analyze the specific heat, the coefficients of thermal expansion as well as the thermodynamic Grüneisen parameter of OsB in a wide temperature range at high pressure. At temperature 300 K, the coefficients of thermal expansion αV by LDA and GGA calculations are 1.67×10 -5 1/K and 2.01×10 -5 1/K, respectively. The specific heat of OsB at constant pressure (volume) is also calculated. Meanwhile, we find that the Debye temperature of OsB increases monotonically with increasing pressure. The present study leads to a better understanding of how the OsB materials respond to pressure and temperature.
Li, Huaming; Tian, Yanting; Sun, Yongli; Li, Mo; Nonequilibrium materials; physics Team; Computational materials science Team
In this work, we apply a general equation of state of liquid and Ab initio molecular-dynamics method to study thermodynamic properties in liquid potassium under high pressure. Isothermal bulk modulus and molar volume of molten sodium are calculated within good precision as compared with the experimental data. The calculated internal energy data and the calculated values of isobaric heat capacity of molten potassium show the minimum along the isothermal lines as the previous result obtained in liquid sodium. The expressions for acoustical parameter and nonlinearity parameter are obtained based on thermodynamic relations from the equation of state. Both parameters for liquid potassium are calculated under high pressure along the isothermal lines by using the available thermodynamic data and numeric derivations. Furthermore, Ab initio molecular-dynamics simulations are used to calculate some thermodynamic properties of liquid potassium along the isothermal lines. Scientific Research Starting Foundation from Taiyuan university of Technology, Shanxi Provincial government (``100-talents program''), China Scholarship Council and National Natural Science Foundation of China (NSFC) under Grant No. 51602213.
Kawai, Soshi
2014-11-01
In this talk, we first propose a numerical strategy that is robust and high-order accurate for enabling to simulate transcritical flows at supercritical pressures under abrupt variations in thermodynamic properties due to the real fluid effects. The method is based on introducing artificial density diffusion in a physically-consistent manner in order to capture the steep variation of thermodynamic properties in transcritical conditions robustly, while solving a pressure evolution equation to achieve pressure equilibrium at the transcritical interfaces. We then discuss the direct numerical simulation (DNS) of transcritical heated turbulent boundary layers on a zero-pressure-gradient flat plate at supercritical pressures. To the best of my knowledge, the present DNS is the first DNS of zero-pressure-gradient flat-plate transcritical turbulent boundary layer. The turbulent kinetic budget indicates that the compressibility effects (especially, pressure-dilatation correlation) are not negligible at the transcritical conditions even if the flow is subsonic. The unique and interesting interactions between the real fluid effects and wall turbulence, and their turbulence statistics, which have never been seen in the ideal-fluid turbulent boundary layers, are also discussed. This work was supported in part by Japan Society for the Promotion of Science (JSPS) Grant-in-Aid for Young Scientists (A) KAKENHI 26709066 and the JAXA International Top Young Fellowship Program.
Xiao-Lin, Zhang; Yuan-Yuan, Wu; Xiao-Hong, Shao; Yong, Lu; Ping, Zhang
2016-05-01
The high pressure behaviors of Th4H15 and ThH2 are investigated by using the first-principles calculations based on the density functional theory (DFT). From the energy-volume relations, the bct phase of ThH2 is more stable than the fcc phase at ambient conditions. At high pressure, the bct ThH2 and bcc Th4H15 phases are more brittle than they are at ambient pressure from the calculated elastic constants and the Poisson ratio. The thermodynamic stability of the bct phase ThH2 is determined from the calculated phonon dispersion. In the pressure domain of interest, the phonon dispersions of bcc Th4H15 and bct ThH2 are positive, indicating the dynamical stability of these two phases, while the fcc ThH2 is unstable. The thermodynamic properties including the lattice vibration energy, entropy, and specific heat are predicted for these stable phases. The vibrational free energy decreases with the increase of the temperature, and the entropy and the heat capacity are proportional to the temperature and inversely proportional to the pressure. As the pressure increases, the resistance to the external pressure is strengthened for Th4H15 and ThH2. Project supported by the Long-Term Subsidy Mechanism from the Ministry of Finance and the Ministry of Education of China.
International Nuclear Information System (INIS)
Beeri, O.
2000-11-01
Thermodynamic and structural studies of numerous intermetallic hydride systems have been performed during the last three decades. Those systems have the potential use for a versatile range of applications such as pure hydrogen storage, heat pumps devices, energy storage, hydrogenation catalysts, thermal compressors, hydrogen purification systems, rechargeable batteries and more. Also, those hydrides have some very interesting fundamental properties related to diffusion studies, gas-solid reactions, isotopic effects, etc. Those applications and fundamentals strongly motivated an extensive research in this field. Most of those studies were limited to the low ( ∼2-x Mn x (0 0, usually the C14 allotrope exists. This property allows for the separation of the compounds properties with respect to their chemical compositions or with respect to their crystallographic structures. The present work includes preparation of the compounds, and their metallurgic, chemical and crystallographic characterization. The reaction of the compounds with hydrogen was studied in a very high-pressure system, which allows pressure-composition (p-c) isotherms measurements of pressures up to 1,000 atm and over a wide range of temperatures. In addition, the reaction of palladium with hydrogen was characterized as well. The palladium-hydrogen system, which is probably the most studied metal-hydrogen system, was chosen to confirm the validity of the experiments and the model calculations. For all samples the isotherms were measured using protium (H 2 ), while in some cases some deuterium (D 2 ) isotherms were measured as well. In this high-pressure range (and actual temperatures) the non-ideality of the gas phase was considered in the isotherm calculations as well as in the thermodynamic calculations. Having the p-c isotherms, the reaction enthalpy change, ΔH, and entropy change, ΔS, were calculated for all systems. Those values of ΔH and ΔS, were found to be in very good agreement with the
New perspective for black hole thermodynamics in Gauss-Bonnet-Born-Infeld massive gravity
International Nuclear Information System (INIS)
Hendi, Seyed Hossein; Li, Gu-Qiang; Mo, Jie-Xiong; Panahiyan, Shahram; Panah, Behzad Eslam
2016-01-01
Following an earlier study regarding Einstein-Gauss-Bonnet-massive black holes in the presence of a Born-Infeld nonlinear electromagnetic field (Hendi, arXiv:1510.00108, 2016), we study thermodynamical structure and critical behavior of these black holes through various methods in this paper. Geometrical thermodynamics is employed to give a picture regarding the phase transition of these black holes. Next, a new method is used to derive critical pressure and radius of the horizon of these black holes. In addition, Maxwell equal area law is employed to study the Van der Waals like behavior of these black holes. Moreover, the critical exponents are calculated and by using Ehrenfest equations, the type of phase transition is determined. (orig.)
New perspective for black hole thermodynamics in Gauss-Bonnet-Born-Infeld massive gravity
Energy Technology Data Exchange (ETDEWEB)
Hendi, Seyed Hossein [Shiraz University, Physics Department and Biruni Observatory, College of Sciences, Shiraz (Iran, Islamic Republic of); Research Institute for Astronomy and Astrophysics of Maragha (RIAAM),Maragha (Iran, Islamic Republic of); Li, Gu-Qiang; Mo, Jie-Xiong [Lingnan Normal University, Institute of Theoretical Physics, Zhanjiang, Guangdong (China); Panahiyan, Shahram [Shiraz University, Physics Department and Biruni Observatory, College of Sciences, Shiraz (Iran, Islamic Republic of); Shahid Beheshti University, Physics Department, Tehran (Iran, Islamic Republic of); Panah, Behzad Eslam [Shiraz University, Physics Department and Biruni Observatory, College of Sciences, Shiraz (Iran, Islamic Republic of)
2016-10-15
Following an earlier study regarding Einstein-Gauss-Bonnet-massive black holes in the presence of a Born-Infeld nonlinear electromagnetic field (Hendi, arXiv:1510.00108, 2016), we study thermodynamical structure and critical behavior of these black holes through various methods in this paper. Geometrical thermodynamics is employed to give a picture regarding the phase transition of these black holes. Next, a new method is used to derive critical pressure and radius of the horizon of these black holes. In addition, Maxwell equal area law is employed to study the Van der Waals like behavior of these black holes. Moreover, the critical exponents are calculated and by using Ehrenfest equations, the type of phase transition is determined. (orig.)
Effects of thermal fluctuations on the thermodynamics of modified Hayward black hole
Energy Technology Data Exchange (ETDEWEB)
Pourhassan, Behnam [Damghan University, School of Physics, Damghan (Iran, Islamic Republic of); Faizal, Mir [University of Lethbridge, Department of Physics and Astronomy, Lethbridge, AB (Canada); Debnath, Ujjal [Indian Institute of Engineering Science and Technology, Shibpur, Department of Mathematics, Howrah (India)
2016-03-15
In this work, we analyze the effects of thermal fluctuations on the thermodynamics of a modified Hayward black hole. These thermal fluctuations will produce correction terms for various thermodynamical quantities like entropy, pressure, internal energy, and specific heats. We also investigate the effect of these correction terms on the first law of thermodynamics. Finally, we study the phase transition for the modified Hayward black hole. It is demonstrated that the modified Hayward black hole is stable even after the thermal fluctuations are taken into account, as long as the event horizon is larger than a certain critical value. (orig.)
Lunine, J. I.; Stevenson, D. J.
1985-01-01
The thermodynamic stability of clathrate hydrate is calculated to predict the formation conditions corresponding to a range of solar system parameters. The calculations were performed using the statistical mechanical theory developed by van der Waals and Platteeuw (1959) and existing experimental data concerning clathrate hydrate and its components. Dissociation pressures and partition functions (Langmuir constants) are predicted at low pressure for CO clathrate (hydrate) using the properties of chemicals similar to CO. It is argued that nonsolar but well constrained noble gas abundances may be measurable by the Galileo spacecraft in the Jovian atmosphere if the observed carbon enhancement is due to bombardment of the atmosphere by clathrate-bearing planetesimals sometime after planetary formation. The noble gas abundances of the Jovian satellite Titan are predicted, assuming that most of the methane in Titan is accreted as clathrate. It is suggested that under thermodynamically appropriate conditions, complete clathration of water ice could have occurred in high-pressure nebulas around giant planets, but probably not in the outer solar nebula. The stability of clathrate in other pressure ranges is also discussed.
New quantum criticality revealed under pressure
International Nuclear Information System (INIS)
Watanabe, Shinji; Miyake, Kazumasa
2017-01-01
Unconventional quantum critical phenomena observed in Yb-based periodic crystals such as YbRh_2Si_2 and β-YbAlB_4 have been one of the central issues in strongly correlated electron systems. The common criticality has been discovered in the quasicrystal Yb_1_5Au_5_1Al_3_4, which surprisingly persists under pressure at least up to P = 1.5 GPa. The T/H scaling where the magnetic susceptibility can be expressed as a single scaling function of the ratio of the temperature T to the magnetic field H has been discovered in the quasicrystal, which is essentially the same as that observed in β-YbAlB_4. Recently, the T/H scaling as well as the common criticality has also been observed even in the approximant crystal Yb_1_4Au_5_1Al_3_5 under pressure. The theory of critical Yb-valence fluctuation gives a natural explanation for these striking phenomena in a unified way. (author)
Energy Technology Data Exchange (ETDEWEB)
Talantsev, Evgueni [Robinson Research Institute, Victoria University of Wellington, Lower Hutt (New Zealand); Crump, Wayne P.; Tallon, Jeffery L. [Robinson Research Institute, Victoria University of Wellington, Lower Hutt (New Zealand); MacDiarmid Institute for Advanced Materials and Nanotechnology, Lower Hutt (New Zealand)
2017-12-15
Key questions for any superconductor include: what is its maximum dissipation-free electrical current (its 'critical current') and can this be used to extract fundamental thermodynamic parameters? Present models focus on depinning of magnetic vortices and implicate materials engineering to maximise pinning performance. But recently we showed that the self-field critical current for thin films is a universal property, independent of microstructure, controlled only by the penetration depth. Here, using an extended BCS-like model, we calculate the penetration depth from the temperature dependence of the superconducting energy gap thus allowing us to fit self-field critical current data. In this way we extract from the T-dependent gap a set of key thermodynamic parameters, the ground-state penetration depth, energy gap and jump in electronic specific heat. Our fits to 79 available data sets, from zinc nanowires to compressed sulphur hydride with critical temperatures of 0.65 to 203 K, respectively, are excellent and the extracted parameters agree well with reported bulk values. Samples include thin films, wires or nanowires of single- or multi-band s-wave and d-wave superconductors of either type I or type II. For multiband or multiphase samples we accurately recover individual band contributions and phase fractions. (copyright 2017 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
DEFF Research Database (Denmark)
Sun, Xiufu; Chen, Ming; Jensen, Søren Højgaard
2012-01-01
A promising way to store wind and solar electricity is by electrolysis of H2O and CO2 using solid oxide electrolysis cells (SOECs) to produce synthetic hydrocarbon fuels that can be used in existing fuel infrastructure. Pressurized operation decreases the cell internal resistance and enables...... improved system efficiency, potentially lowering the fuel production cost significantly. In this paper, we present a thermodynamic analysis of synthetic methane and dimethyl ether (DME) production using pressurized SOECs, in order to determine feasible operating conditions for producing the desired......, and outlet gas composition. For methane production, low temperature and high pressure operation could improve the system efficiency, but might lead to a higher capital cost. For DME production, high pressure SOEC operation necessitates higher operating temperature in order to avoid carbon formation at higher...
A study of fluid alkali metals in the critical region
International Nuclear Information System (INIS)
Balasubramanian, R.
2006-01-01
On the basis of the generalised van der Waals equation of state, Riedel's thermodynamic similarity parameter, a measure of the temperature dependence of vapour pressure in the critical region is determined for caesium, rubidium and potassium. This generalised equation differs from the known van der Waals equation of state by the modified expression for molecular pressure. The results of determination of Riedel's thermodynamic similarity parameter of caesium, rubidium and potassium are in good agreement with experimental data. Moreover, the given generalised van der Waals equation of state yields a better fit with experimental data on Riedel's thermodynamic similarity parameter for fluid alkali metals when compared with other correlations such as Van Ness and Abbott equation, Pitzer expansion, Pitzer acentric factor correlation, modified Rackett technique, Lee-Kesler vapour pressure relation and Clausius-Clayperon equation
Chemical Thermodynamics Vol. 12 - Chemical Thermodynamics of tin
International Nuclear Information System (INIS)
Gamsjaeger, Heinz; GAJDA, Tamas; Sangster, James; Saxena, Surendra K.; Voigt, Wolfgang; Perrone, Jane
2012-01-01
This is the 12th volume of a series of expert reviews of the chemical thermodynamics of key chemical elements in nuclear technology and waste management. This volume is devoted to the inorganic species and compounds of tin. The tables contained in Chapters III and IV list the currently selected thermodynamic values within the NEA TDB Project. The database system developed at the NEA Data Bank, see Section II.6, assures consistency among all the selected and auxiliary data sets. The recommended thermodynamic data are the result of a critical assessment of published information. The values in the auxiliary data set, see Tables IV-1 and IV-2, have been adopted from CODATA key values or have been critically reviewed in this or earlier volumes of the series
Thermodynamics phase changes of nanopore fluids
Islam, Akand W.
2015-07-01
The van der Waals (vdW) equation (Eq.) is modified to describe thermodynamic of phase behavior of fluids confined in nanopore. Our aim is to compute pressures exerted by the fluid molecules and to investigate how they change due to pore proximity by assuming the pore wall is inert. No additional scaling of model parameters is imposed and original volume and energy parameters are used in the calculations. Our results clearly show the phase changes due to confinement. The critical shifts of temperatures and pressures are in good agreement compared to the laboratory data and molecular simulation. Peng-Robinson (PR) equation-of-state (EOS) has resulted in different effect than the vdW. This work delivers insights into the nature of fluid behavior in extremely low-permeability nanoporous media, especially in the tight shale reservoirs, below the critical temperatures. © 2015 Elsevier B.V.
Thermodynamics phase changes of nanopore fluids
Islam, Akand W.; Patzek, Tadeusz; Sun, Alexander Y.
2015-01-01
The van der Waals (vdW) equation (Eq.) is modified to describe thermodynamic of phase behavior of fluids confined in nanopore. Our aim is to compute pressures exerted by the fluid molecules and to investigate how they change due to pore proximity by assuming the pore wall is inert. No additional scaling of model parameters is imposed and original volume and energy parameters are used in the calculations. Our results clearly show the phase changes due to confinement. The critical shifts of temperatures and pressures are in good agreement compared to the laboratory data and molecular simulation. Peng-Robinson (PR) equation-of-state (EOS) has resulted in different effect than the vdW. This work delivers insights into the nature of fluid behavior in extremely low-permeability nanoporous media, especially in the tight shale reservoirs, below the critical temperatures. © 2015 Elsevier B.V.
Thermodynamic and fluid mechanic analysis of rapid pressurization in a dead-end tube
Leslie, Ian H.
1989-01-01
Three models have been applied to very rapid compression of oxygen in a dead-ended tube. Pressures as high as 41 MPa (6000 psi) leading to peak temperatures of 1400 K are predicted. These temperatures are well in excess of the autoignition temperature (750 K) of teflon, a frequently used material for lining hoses employed in oxygen service. These findings are in accord with experiments that have resulted in ignition and combustion of the teflon, leading to the combustion of the stainless steel braiding and catastrophic failure. The system analyzed was representative of a capped off-high-pressure oxygen line, which could be part of a larger system. Pressurization of the larger system would lead to compression in the dead-end line, and possible ignition of the teflon liner. The model consists of a large plenum containing oxygen at the desired pressure (500 to 6000 psi). The plenum is connected via a fast acting valve to a stainless steel tube 2 cm inside diameter. Opening times are on the order of 15 ms. Downstream of the valve is an orifice sized to increase filling times to around 100 ms. The total length from the valve to the dead-end is 150 cm. The distance from the valve to the orifice is 95 cm. The models describe the fluid mechanics and thermodynamics of the flow, and do not include any combustion phenomena. A purely thermodynamic model assumes filling to be complete upstream of the orifice before any gas passes through the orifice. This simplification is reasonable based on experiment and computer modeling. Results show that peak temperatures as high as 4800 K can result from recompression of the gas after expanding through the orifice. An approximate transient model without an orifice was developed assuming an isentropic compression process. An analytical solution was obtained. Results indicated that fill times can be considerably shorter than valve opening times. The third model was a finite difference, 1-D transient compressible flow model. Results from
Directory of Open Access Journals (Sweden)
W. Leini
2018-03-01
Full Text Available We have investigated the phonon, elastic and thermodynamic properties of L1_2 phase Al_3Ta by density functional theory approach combining with quasi-harmonic approximation model. The results of phonon band structure shows that L1_2 phase Al_3Ta possesses dynamical stability in the pressure range from 0 to 80 GPa due to the absence of imaginary frequencies. The pressure dependences of the elastic constants C_ij, bulk modulus B, shear modulus G, Young's modulus Y, B/G and Poisson's ratio ν have been analysed. The elastic constants are satisfied with mechanical stability criteria up to the external pressure of 80 GPa. The results of the elastic properties studies show that Al_3Ta compound possesses a higher hardness, improved ductility and plasticity under higher pressures. Further, we systematically investigate the thermodynamic properties, such as the Debye temperature Θ, heat capacity C_p, and thermal expansion coefficient α, and provide the relationships between thermal parameters and pressure.
Thermodynamics of volume-collapse transitions in cerium and related compounds
International Nuclear Information System (INIS)
Bustingorry, S.; Jagla, E.A.; Lorenzana, J.
2005-01-01
We present a non-linear elastic model of a coherent transition with discontinuous volume change in an isotropic solid. The model reproduces the anomalous thermodynamics typical of coherent equilibrium including intrinsic hysteresis (for a pressure driven experiment) and a negative bulk modulus. The novelty of the model is that the statistical mechanics solution can be easily worked out. We find that coherency leads to an infinite-range density-density interaction, which drives classical critical behavior. The pressure width of the hysteresis loop shrinks with increasing temperature, ending at a critical point at a temperature related to the shear modulus. The bulk modulus softens with a 1/2 exponent at the transition even far from the critical point. Many well known features of the phase diagram of Ce and related systems are explained by the model
Multi-band description of the specific heat and thermodynamic critical field in MgB2 superconductor
Szcześniak, R.; Jarosik, M. W.; Tarasewicz, P.; Durajski, A. P.
2018-05-01
The thermodynamic properties of MgB2 superconductor can be explained using the multi-band models. In the present paper we have examined the experimental data available in literature and we have found out that it is possible to reproduce the measured values of the superconducting energy gaps, the thermodynamic critical magnetic field and specific heat jump within the framework of two-band Eliashberg formalism and appropriate defined free energy difference between superconducting and normal state. Moreover, we found that the obtained results differ significantly from the predictions of the conventional Bardeen-Cooper-Schrieffer theory.
A study of fluid alkali metals in the critical region
Energy Technology Data Exchange (ETDEWEB)
Balasubramanian, R. [Department of Physics, Kongu Engineering College, Perundurai, Erode 638 052, Tamil Nadu (India)]. E-mail: drrbala@yahoo.com
2006-05-31
On the basis of the generalised van der Waals equation of state, Riedel's thermodynamic similarity parameter, a measure of the temperature dependence of vapour pressure in the critical region is determined for caesium, rubidium and potassium. This generalised equation differs from the known van der Waals equation of state by the modified expression for molecular pressure. The results of determination of Riedel's thermodynamic similarity parameter of caesium, rubidium and potassium are in good agreement with experimental data. Moreover, the given generalised van der Waals equation of state yields a better fit with experimental data on Riedel's thermodynamic similarity parameter for fluid alkali metals when compared with other correlations such as Van Ness and Abbott equation, Pitzer expansion, Pitzer acentric factor correlation, modified Rackett technique, Lee-Kesler vapour pressure relation and Clausius-Clayperon equation.
Blanco, Sofía T; Gil, Laura; García-Giménez, Pilar; Artal, Manuela; Otín, Santos; Velasco, Inmaculada
2009-05-21
Critical properties and volumetric behavior for the {CO2(1)+C3H8(2)} system have been studied. The critical locus was measured with a flow apparatus and detected by critical opalescence. For the mixtures, repeatabilities in critical temperature and pressure are rTcStructural properties such as direct and total correlation function integrals and cluster size were calculated using the Krichevskii function concept. Both the critical and volumetric behavior have been compared with literature data and with those obtained from the PC-SAFT and Patel-Teja equations of state.
Advanced classical thermodynamics
International Nuclear Information System (INIS)
Emanuel, G.
1987-01-01
The theoretical and mathematical foundations of thermodynamics are presented in an advanced text intended for graduate engineering students. Chapters are devoted to definitions and postulates, the fundamental equation, equilibrium, the application of Jacobian theory to thermodynamics, the Maxwell equations, stability, the theory of real gases, critical-point theory, and chemical thermodynamics. Diagrams, graphs, tables, and sample problems are provided. 38 references
Thermodynamics of the vaporization of uranium tetrabromide
International Nuclear Information System (INIS)
Singh, Z.; Prasad, R.; Venugopal, P.V.; Roy, K.N.; Sood, D.D.
1981-01-01
Vapour pressures of solid and liquid uranium tetrabromide have been measured in the temperature range of 696 to 805 K and 805 to 1003 K respectively by transpiration and evaporation-temperature techniques. The vapour pressures obtained by the two techniques are in good agreement and have been combined to give the reported vapour-pressure equations for solid and liquid uranium tetrabromide. The melting temperature, the normal boiling temperature, the standard enthalpy of vaporization ΔH 0 (vap, 298.15 K), and the standard entropy of vaporization ΔS 0 (vap, 298.15 K) are reported. The enthalpy of fusion ΔH 0 (fus, 802 K) is also reported. The thermodynamic quantities from the present study are compared with those in the literature and critically analysed. (author)
Critical phenomena of static charged AdS black holes in conformal gravity
Directory of Open Access Journals (Sweden)
Wei Xu
2014-09-01
Full Text Available The extended thermodynamics of static charged AdS black holes in conformal gravity is analyzed. The P–V criticality of these black holes has some unusual features. There exists a single critical point with critical temperature Tc and critical pressure Pc. At fixed T>Tc (or at fixed P>Pc, there are two zeroth order phase transition points but no first order phase transition points. The systems favors large pressure states at constant T, or high temperature states at constant P.
Characterization of the superconducting state in hafnium hydride under high pressure
Duda, A. M.; Szewczyk, K. A.; Jarosik, M. W.; Szcześniak, K. M.; Sowińska, M. A.; Szcześniak, D.
2018-05-01
The hydrogen-rich compounds at high pressure may exhibit notably high superconducting transition temperatures. In the paper, we have calculated the basic thermodynamic parameters of the superconducting state in two selected phases of HfH2 hydride under high-pressure respectively at 180 GPa for Cmma and 260 GPa for P21 / m . Calculations has been conducted in the framework of the Eliashberg formalism. In particular, we have determined the values of the critical temperature (TC) to be equal to 8 K and 13 K for the Cmma and P21 / m phases, respectively. Moreover, we have estimated other thermodynamic properties such as the order parameter (Δ (T)) , the thermodynamic critical field (HC (T)) , and the specific heat for the normal (CN) and superconducting (CS) state. Finally, we have shown that the characteristic ratios: RΔ = 2 Δ (0) /kBTC and RC = ΔC (TC) /CN (TC) , which are related to the above thermodynamic functions, slightly differ from the predictions of the Bardeen-Cooper-Schrieffer theory due to the strong-coupling and retardation effects.
International Nuclear Information System (INIS)
Qin Shaojin; Yu Lu.
1996-03-01
The critical exponent of the momentum distribution near k F , 3k F and 5k F are studied numerically for one-dimensional U → ∞ Hubbard model, using finite size systems and extrapolating them to the thermodynamic limit. Results at k F agree with earlier calculations, while at 3k F exponents less than 1 are obtained for finite size systems with extrapolation to 1 (regular behaviour) in the thermodynamic limit, in contrast to earlier analytic prediction 9/8. The distribution is regular at 5k F even for finite systems. The singularity near 3k F is interpreted as due to low energy excitations near 3k F in finite systems. (author). 18 refs, 4 figs, 1 tab
International Nuclear Information System (INIS)
Chieux, P.; Damay, P.
1978-01-01
A quantitative comparison is made between the thermodynamics as obtained from the long wavelength limit of a small angle neutron scattering experiment in the vicinity of a liquid-liquid critical point for the Li-ND 3 system and the data obtained from vapour pressure measurements. The agreement is fair. It is shown how the comparison always implies an underlying model of the interacting species leading to the liquid-liquid phase separation. (Auth.)
Dual QCD thermodynamics and quark–gluon plasma
International Nuclear Information System (INIS)
Chandola, H.C.; Punetha, Garima; Dehnen, H.
2016-01-01
Using grand canonical ensemble formulation of a multi-particle statistical system, the thermodynamical description of dual QCD based on magnetic symmetry has been presented and analyzed for the quark–gluon plasma phase of hadronic matter. The dual QCD based bag construction has been shown to lead to the radial pressure on bag surface in terms of the vector glueball masses of magnetically condensed QCD vacuum. Constructing the grand canonical partition function, the energy density and plasma pressure have been derived and used to compute the critical temperatures for QGP–hadron phase transition along with its dynamics. A comparison of the values of critical temperatures for QGP–hadron phase transition with those obtained for the deconfinement-phase transition, has been shown to lead to either the relaxation of the system via a mixed phase of QGP and hot hadron gas or go through a crossover. The associated profiles of the normalized energy density and specific heat have been shown to lead to a large latent heat generation and indicate the onset of a first-order QGP phase transition which turns into a rapid crossover for the case of temperature dependent bag parameter. The squared speed of sound has been shown to act as a physical measure of large thermodynamical fluctuations near transition point. The possible implications of trace anomaly and conformal measure on QGP formation have also been discussed.
P-V criticality of conformal gravity holography in four dimensions
Pradhan, Parthapratim
2018-02-01
We examine the critical behavior, i.e. P-V criticality of conformal gravity (CG) in an extended phase space in which the cosmological constant should be interpreted as a thermodynamic pressure and the corresponding conjugate quantity as a thermodynamic volume. The main potential point of interest in CG is that there exists a nontrivial Rindler parameter (a) in the spacetime geometry. This geometric parameter has an important role to construct a model for gravity at large distances where the parameter “a” actually originates. We also investigate the effect of the said parameter on the black hole (BH) thermodynamic equation of state, critical constants, Reverse Isoperimetric Inequality, first law of thermodynamics, Hawking-Page phase transition and Gibbs free energy for this BH. We speculate that due to the presence of the said parameter, there has been a deformation in the shape of the isotherms in the P-V diagram in comparison with the charged-anti de Sitter (AdS) BH and the chargeless-AdS BH. Interestingly, we find that the critical ratio for this BH is ρc = Pcvc Tc = 3 2 32 ‑ 23, which is greater than the charged AdS BH and Schwarzschild-AdS BH, i.e. ρcCG : ρ cSch-AdS : ρ cRN-AdS = 0.67 : 0.50 : 0.37. The symbols are defined in the main work. Moreover, we observe that the critical ratio has a constant value and it is independent of the nontrivial Rindler parameter (a). Finally, we derive the reduced equation of state in terms of the reduced temperature, the reduced volume and the reduced pressure, respectively.
International Nuclear Information System (INIS)
Sato, H.
2009-01-01
Swelling pressure was discussed focusing on the thermodynamic properties of water on smectite (montmorillonite) which is the major clay mineral constituent of the bentonite buffer. The thermodynamic data of the water on the smectite surface were obtained as a function of water content and temperature in a range of dry density 0.6-0.9 Mg/m 3 . Purified Na-smectite of which all interlayer cations were exchanged with Na+ ions, was used. The activity (a H 2 O ) and the relative partial molar Gibbs free energy (ΔG H 2 O ) of the water were obtained at 25 C. Both a H 2 O and ΔG H 2 O decreased with a decrease of water content, and similar results were obtained to data reported for montmorillonite (Kunipia-F bentonite). Since the specific surface area of smectite is about 800 m 2 /g, water up to approximately 2 water layers from smectite surface is thermodynamically evaluated to be bound. Swelling pressure versus smectite partial density was calculated based on ΔG H 2 O and compared to data experimentally obtained for various kinds of bentonites. The calculated results were in good agreement with the measured data over the range of smectite partial density between 1.0 and 2.0 Mg/m 3 . (author)
Thermodynamic Analysis of a Supercritical Mercury Power Cycle
Energy Technology Data Exchange (ETDEWEB)
Roberts, Jr, A S
1969-04-15
An heat engine is considered which employs supercritical mercury as the working fluid and a magnetohydrodynamic (MHD) generator for thermal to electrical energy conversion. The main thrust of the paper is power cycle thermodynamics, where constraints are imposed by utilizing a MHD generator operating between supercritical, electrically conducting states of the working fluid; and, pump work is accomplished with liquid mercury. The temperature range is approximately 300 to 2200 K and system pressure is > 1,500 atm. Equilibrium and transport properties are carefully considered since these are known to vary radically in the vicinity of the critical point, which is found near the supercritical states of interest. A maximum gross plant efficiency is 20% with a regenerator effectiveness of 90% and greater, a cycle pressure ratio of two, and with highly efficient pump and generator. Certain specified cycle irreversibilities and others such as heat losses and heat exchanger pressure drops, which are not accounted for explicitly, reduce the gross plant efficiency to a few per cent. Experimental efforts aimed at practical application of the power cycle are discouraged by the marginal thermodynamic performance predicted by this study, unless such applications are insensitive to gross cycle efficiency.
Thermodynamic Analysis of a Supercritical Mercury Power Cycle
International Nuclear Information System (INIS)
Roberts, A.S. Jr.
1969-04-01
An heat engine is considered which employs supercritical mercury as the working fluid and a magnetohydrodynamic (MHD) generator for thermal to electrical energy conversion. The main thrust of the paper is power cycle thermodynamics, where constraints are imposed by utilizing a MHD generator operating between supercritical, electrically conducting states of the working fluid; and, pump work is accomplished with liquid mercury. The temperature range is approximately 300 to 2200 K and system pressure is > 1,500 atm. Equilibrium and transport properties are carefully considered since these are known to vary radically in the vicinity of the critical point, which is found near the supercritical states of interest. A maximum gross plant efficiency is 20% with a regenerator effectiveness of 90% and greater, a cycle pressure ratio of two, and with highly efficient pump and generator. Certain specified cycle irreversibilities and others such as heat losses and heat exchanger pressure drops, which are not accounted for explicitly, reduce the gross plant efficiency to a few per cent. Experimental efforts aimed at practical application of the power cycle are discouraged by the marginal thermodynamic performance predicted by this study, unless such applications are insensitive to gross cycle efficiency
High energy lithium-oxygen batteries - Transport barriers and thermodynamics
Das, Shyamal K.
2012-01-01
We show that it is possible to achieve higher energy density lithium-oxygen batteries by simultaneously lowering the discharge overpotential and increasing the discharge capacity via thermodynamic variables alone. By assessing the relative effects of temperature and pressure on the cell discharge profiles, we characterize and diagnose the critical roles played by multiple dynamic processes that have hindered implementation of the lithium-oxygen battery. © 2012 The Royal Society of Chemistry.
Stability of black holes based on horizon thermodynamics
Directory of Open Access Journals (Sweden)
Meng-Sen Ma
2015-12-01
Full Text Available On the basis of horizon thermodynamics we study the thermodynamic stability of black holes constructed in general relativity and Gauss–Bonnet gravity. In the framework of horizon thermodynamics there are only five thermodynamic variables E, P, V, T, S. It is not necessary to consider concrete matter fields, which may contribute to the pressure of black hole thermodynamic system. In non-vacuum cases, we can derive the equation of state, P=P(V,T. According to the requirements of stable equilibrium in conventional thermodynamics, we start from these thermodynamic variables to calculate the heat capacity at constant pressure and Gibbs free energy and analyze the local and global thermodynamic stability of black holes. It is shown that P>0 is the necessary condition for black holes in general relativity to be thermodynamically stable, however this condition cannot be satisfied by many black holes in general relativity. For black hole in Gauss–Bonnet gravity negative pressure can be feasible, but only local stable black hole exists in this case.
Santos, Ana Filipa L O M; Oliveira, Juliana A S A; Ribeiro da Silva, Maria D M C; Monte, Manuel J S
2016-03-01
This work reports the experimental determination of relevant thermodynamic properties and the characterization of luminescence properties of the following polycyclic aromatic hydrocarbons (PAHs): 2,6-diethylnaphthalene, 2,6-diisopropylnaphthalene and 2,6-di-tert-butylnaphthalene. The standard (p(o) = 0.1 MPa) molar enthalpies of combustion, ΔcHm(o), of the three compounds were determined using static bomb combustion calorimetry. The vapor pressures of the crystalline phase of 2,6-diisopropylnaphthalene and 2,6-di-tert-butylnaphthalene were measured at different temperatures using the Knudsen effusion method and the vapor pressures of both liquid and crystalline phases of 2,6-diethylnaphthalene were measured by means of a static method. The temperatures and the molar enthalpies of fusion of the three compounds were determined using differential scanning calorimetry. The gas-phase molar heat capacities and absolute entropies of the three 2,6-dialkylnaphthalenes studied were determined computationally. The thermodynamic stability of the compounds in both the crystalline and gaseous phases was evaluated by the determination of the Gibbs energies of formation and compared with the ones reported in the literature for 2,6-dimethylnaphthalene. From fluorescence spectroscopy measurements, the optical properties of the compounds studied and of naphthalene were evaluated in solution and in the solid state. Copyright © 2015 Elsevier Ltd. All rights reserved.
da Rocha-Neto, J. F.; Morais, B. R.
2018-04-01
In the context of the teleparallel equivalent of general relativity the concept of gravitational pressure and gravitational energy-momentum arisen in a natural way. In the case of a Friedmann-Lemaitre-Robertson-Walker space FLRW we obtain the total energy contained inside the apparent horizon and the radial pressure over the apparent horizon area. We use these definitions to written a thermodynamics relation TAdSA = dEA+PAdVA at the apparent horizon, where EA is the total energy inside the apparent horizon, VA is the areal volume of the apparent horizon, PA is the radial pressure over the apparent horizon area, SA is the entropy which can be assumed as one quarter of the apparent horizon area only for a non stationary apparent horizon. We identify TA as the temperature at the surface of the apparent horizon. We shown that for all expanding accelerated FLRW model of universe the radial pressure is positive.
$P-V$ criticality of a specific black hole in $f(R)$ gravity coupled with Yang-Mills field arXiv
Övgün, Ali
In this paper, we study the $P-v$ criticality of a specific charged AdS type black hole (SBH) in $f(R)$ gravity coupled with Yang-Mills field. In the extended phase space, we treat the cosmological constant as a thermodynamic pressure. After we study the various thermodynamical quantities, we show that the thermodynamic properties of the SBH behave as a Van der Waals liquid-gas system at the critical points and there is a first order phase transition between small-large SBH.
Thermodynamic behaviour of ruthenium at high temperatures
International Nuclear Information System (INIS)
Garisto, F.
1988-01-01
Thermodynamic equilibrium calculations are used to determine the chemical speciation of ruthenium under postulated reactor accident conditions. The speciation of ruthenium is determined for various values of temperature, pressure, oxygen partial pressure and ruthenium concentration. The importance of these variables, in particular the oxygen partial pressure, in determining the volatility of ruthenium is clearly demonstrated in this report. Reliable thermodynamic data are required to determine the behaviour of ruthenium using equilibrium calculations. Therefore, it was necessary to compile a thermodynamic database for the ruthenium species that can be formed under reactor accident conditions. The origin of the thermodynamic data for the ruthenium species included in our calculations is discussed in detail in Appendix A. 23 refs
Asymmetry of critical closing pressure following head injury
Kumar, A; Schmidt, E; Hiler, M; Smielewski, P; Pickard, J; Czosnyka, M
2005-01-01
Objective: Critical closing pressure (CCP) is the arterial pressure below which the vessels collapse. Hypothetically it is the sum of intracranial pressure (ICP) and vessel wall tension in the cerebral circulation. This study investigated transhemispherical asymmetry of CCP by studying its correlation with radiological findings on computed tomography (CT) scans in head injury patients.
Experimental determination of critical data of liquid molybdenum
International Nuclear Information System (INIS)
Seydel, U.; Fucke, W.
1978-01-01
The submicrosecond resistive pulse heating of wire-shaped metallic samples in a highly incompressible medium leads to a thermodynamic state very close to the critical point of the liquid metal. The additional application of a static pressure may result in a critical or supercritical transition. First results on the critical data of molybdenum are reported: Tsub(c) = (11 150 +- 550) K, psub(c) = (5460 +- 1160) bar, vsub(c) = (36.5 +- 3.5) cm 3 mol -1 . (author)
Thermodynamics with pressure and volume under charged particle absorption
Gwak, Bogeun
2017-11-01
We investigate the variation of the charged anti-de Sitter black hole under charged particle absorption by considering thermodynamic volume. When the energy of the particle is considered to contribute to the internal energy of the black hole, the variation exactly corresponds to the prediction of the first law of thermodynamics. Nevertheless, we find the decrease of the Bekenstein-Hawking entropy for extremal and near-extremal black holes under the absorption, which is an irreversible process. This violation of the second law of thermodynamics is only found when considering thermodynamic volume. We test the weak cosmic censorship conjecture affected by the violation. Fortunately, the conjecture is still valid, but extremal and near-extremal black holes do not change their configurations when any particle enters the black hole. This result is quite different from the case in which thermodynamic volume is not considered.
Modeling Xenon Tank Pressurization using One-Dimensional Thermodynamic and Heat Transfer Equations
Gilligan, Ryan P.; Tomsik, Thomas M.
2017-01-01
As a first step in understanding what ground support equipment (GSE) is required to provide external cooling during the loading of 5,000 kg of xenon into 4 aluminum lined composite overwrapped pressure vessels (COPVs), a modeling analysis was performed using Microsoft Excel. The goals of the analysis were to predict xenon temperature and pressure throughout loading at the launch facility, estimate the time required to load one tank, and to get an early estimate of what provisions for cooling xenon might be needed while the tanks are being filled. The model uses the governing thermodynamic and heat transfer equations to achieve these goals. Results indicate that a single tank can be loaded in about 15 hours with reasonable external coolant requirements. The model developed in this study was successfully validated against flight and test data. The first data set is from the Dawn mission which also utilizes solar electric propulsion with xenon propellant, and the second is test data from the rapid loading of a hydrogen cylindrical COPV. The main benefit of this type of model is that the governing physical equations using bulk fluid solid temperatures can provide a quick and accurate estimate of the state of the propellant throughout loading which is much cheaper in terms of computational time and licensing costs than a Computation Fluid Dynamics (CFD) analysis while capturing the majority of the thermodynamics and heat transfer.
Global thermodynamics of confined inhomogeneous dilute gases: A semi-classical approach
Poveda-Cuevas, F. J.; Reyes-Ayala, I.; Seman, J. A.; Romero-Rochín, V.
2018-04-01
In this work we present our contribution to the Latin American School of Physics "Marcos Moshinsky" 2017 on Quantum Correlations which was held in Mexico City during the summer of 2017. We review the efforts that have been done to construct a global thermodynamic description of ultracold dilute gases confined in inhomogeneous potentials. This is difficult because the presence of this non-uniform trap makes the pressure of the gas to be a spatially dependent variable and its volume an ambiguously defined quantity. In this paper we introduce new global thermodynamic variables, equivalent to pressure and volume, and propose a realistic model of the equation of state of the system. This model is based on a mean-field approach which asymptotically reaches the Thomas-Fermi limit for a weakly interacting Bose gas. We put special emphasis to the transition between the normal and superfluid phases by studying the behavior of the isothermal compressibility across the transition. We reveal how the potential modifies the critical properties of the transition by determining the critical exponents associated to the divergences not of the susceptibilities but of their derivatives.
Thermodynamic study of selected monoterpenes III
International Nuclear Information System (INIS)
Štejfa, Vojtěch; Fulem, Michal; Růžička, Květoslav; Červinka, Ctirad
2014-01-01
Highlights: • (−)-trans-Pinane, (+)-Δ-carene, eucalyptol, and limonene were studied. • New thermodynamic data were measured and calculated. • Many of thermodynamic data are reported for the first time. - Abstract: A thermodynamic study of selected monoterpenes, (−)-trans-pinane, (+)-Δ-carene, eucalyptol, (+)-limonene, and (−)-limonene, is presented in this work. The vapor pressure measurements were performed using the static method over the environmentally important temperature range (238 to 308) K. Liquid heat capacities were measured by Tian–Calvet calorimetry in the temperature interval (258 to 355) K. The phase behavior was investigated by differential scanning calorimetry (DSC) from T = 183 K. The thermodynamic properties in the ideal-gas state were calculated by combining statistical thermodynamic and density functional theory (DFT) calculations. Calculated ideal-gas heat capacities and experimental data for vapor pressures and condensed phase heat capacities were treated simultaneously to obtain a consistent thermodynamic description
Thermodynamics of natural and industrial waters
Energy Technology Data Exchange (ETDEWEB)
Pitzer, K.S.
1991-08-01
The most effective general formulations of thermodynamic equations for multicomponent aqueous solutions are discussed with respect to various ranges of temperature, pressure and composition with emphasis on solutes important in natural or industrial waters. A familiar equation in molality and in excess Gibbs energy is very successful up to 300{degree}C and ionic strength 6 mol{center dot}kg{sup {minus}1}, and can often be extended to 350{degree}C or above at high pressure and in favorable cases to ionic strength 12 or even 20. Alternate methods valid to higher solute compositions, even to pure fused salts, are described. A more difficult situation arises near the critical point of water where the compressibility becomes infinite and a Helmholtz energy basis must be adopted. Existing equations for this range and still higher temperatures and pressures are considered and possible improvements discussed. 85 refs., 13 figs., 3 tabs.
Laser-irradiated thermodynamic behaviors of spallation and recombination at solid-state interface
International Nuclear Information System (INIS)
Lai, H.-Y.; Huang, P.-H.
2008-01-01
A microscopic insight of interfacial spallation and recombination behaviors at multilayer thin-film interface induced by incident femtosecond pulsed laser is presented in this paper. Such two different aforementioned behaviors are investigated via the thermodynamic trajectories obtained by using standard Lennard-Jones (L-J) molecular dynamics (MD) simulation. Based on the simulation results, the interfacial damages of multilayer thin film are dominated by a critical threshold that induces an extraordinary expansive dynamics and phase transitions leading to the structural softened and tensile spallation at interface. The critical damage threshold is evaluated at around 8.5 J/m 2 which governs the possible occurrence of two different regimes, i.e. interfacial spallaiton and recombination. In interfacial damage region, quasi-isothermal thermodynamic trajectories can be observed after the interfacial spallation occurs. Moreover, the result of thermodynamic trajectories analyses indicates that, the relaxation of pressure wave may cause the over-heated interfacial zone to reduce volumetric density, thus leading to structural softness and even weaken interfacial structural strength. The crucial effect leading to the phenomenon of low tension spallation is identified
Thermodynamic properties of amphiphilic antidepressant drug citalopram HBr
International Nuclear Information System (INIS)
Usman, M.; Khan, A.
2010-01-01
Association characteristics of antidepressant during Citalopram hydrobromide in water Have been examined and its thermodynamic parameters have been calculated using tensiometery and conductometry. The critical micelle concentration (cmc) was determined by surface tension measurement at 30 deg. C and Surface activity was studied by measuring surface parameters i.e. surface pressure, JI, surface excess concentration, area per molecule of drug and standard Gibbs free energy of adsorption, delta G. The electrical conductivity was measured as a function of concentration at various temperatures and cmc was calculated in the temperature range 20-50 deg. C. Thermodynamic parameters i.e. standard free energy of micellization, delta G standard enthalpy of micellization, delta H/sub m/ and standard entropy of micellization, delta S/sub m/ were calculated from cmc value using closed association model. (author)
Critical, statistical, and thermodynamical properties of lattice models
Energy Technology Data Exchange (ETDEWEB)
Varma, Vipin Kerala
2013-10-15
In this thesis we investigate zero temperature and low temperature properties - critical, statistical and thermodynamical - of lattice models in the contexts of bosonic cold atom systems, magnetic materials, and non-interacting particles on various lattice geometries. We study quantum phase transitions in the Bose-Hubbard model with higher body interactions, as relevant for optical lattice experiments of strongly interacting bosons, in one and two dimensions; the universality of the Mott insulator to superfluid transition is found to remain unchanged for even large three body interaction strengths. A systematic renormalization procedure is formulated to fully re-sum these higher (three and four) body interactions into the two body terms. In the strongly repulsive limit, we analyse the zero and low temperature physics of interacting hard-core bosons on the kagome lattice at various fillings. Evidence for a disordered phase in the Ising limit of the model is presented; in the strong coupling limit, the transition between the valence bond solid and the superfluid is argued to be first order at the tip of the solid lobe.
Critical, statistical, and thermodynamical properties of lattice models
International Nuclear Information System (INIS)
Varma, Vipin Kerala
2013-10-01
In this thesis we investigate zero temperature and low temperature properties - critical, statistical and thermodynamical - of lattice models in the contexts of bosonic cold atom systems, magnetic materials, and non-interacting particles on various lattice geometries. We study quantum phase transitions in the Bose-Hubbard model with higher body interactions, as relevant for optical lattice experiments of strongly interacting bosons, in one and two dimensions; the universality of the Mott insulator to superfluid transition is found to remain unchanged for even large three body interaction strengths. A systematic renormalization procedure is formulated to fully re-sum these higher (three and four) body interactions into the two body terms. In the strongly repulsive limit, we analyse the zero and low temperature physics of interacting hard-core bosons on the kagome lattice at various fillings. Evidence for a disordered phase in the Ising limit of the model is presented; in the strong coupling limit, the transition between the valence bond solid and the superfluid is argued to be first order at the tip of the solid lobe.
International Nuclear Information System (INIS)
Han, Kewei; Xia, Shuqian; Ma, Peisheng; Yan, Fangyou; Liu, Tao
2013-01-01
Highlights: • The critical properties of seven binary mixtures related to gasoline were measured. • The critical properties of the five systems containing MTBE were reported for the first time. • Binary interaction parameters were fitted by experimental data using PR EOS with Wong–Sandler mixing rule. • Redlich–Kister equation was used to correlate the experimental data. -- Abstract: A set of high-pressure view apparatus was designed for determining the critical properties of chemicals. In order to check the reliability of the apparatus, the critical temperatures (T c ) and critical pressures (P c ) of pure n-heptane, cyclohexane, methanol, ethanol, 1-propanol, methyl tert-butyl ether (MTBE), and binary mixture n-hexane + ethanol were measured. The experimental data were in good agreement with the literature data, which proves the reliability of the apparatus used in the work. The critical temperatures and critical pressures of five binary mixtures containing gasoline additive (MTBE + n-heptane, MTBE + cyclohexane, MTBE + methanol, MTBE + ethanol, MTBE + 1-propanol) were measured using the high-pressure view cell with visual observation. The critical temperatures and critical pressures for the five binary mixtures were all reported for the first time. In addition, the critical temperatures and critical pressures of the binary mixture n-heptane + cyclohexane (two of main components in gasoline) were also measured. All the critical lines for the mixtures studied are continuous which connect the critical points of the two pure components, indicating their phase diagrams belong to type I proposed by Scott and van Konynenburg. The critical points of these systems were calculated by the Peng–Robinson equation of state with the Wong–Sandler mixing rule. This model could calculate the critical properties of the mixtures well with the binary interaction parameter k ij obtained by fitting the experimental critical data. And the experimental data were all
LH2 tank pressure control by thermodynamic vent system (TVS) at zero gravity
Wang, B.; Huang, Y. H.; Chen, Z. C.; Wu, J. Y.; Li, P.; Sun, P. J.
2017-02-01
Thermodynamic vent system (TVS) is employed for pressure control of propellant tanks at zero gravity. An analytical lumped parameter model is developed to predict pressure variation in an 18.09 m3 liquid hydrogen tank equipped with TVS. Mathematical simulations are carried out assuming tank is filled up to 75% volume (liquid mass equals to 945 kg) and is subjected to heat flux of 0.76 W/m2. Tank pressure controls at 165.5-172.4, 165.5-179.3 and 165.5-182.2 kPa are compared with reference to number of vent cycles, vent duration per cycle and loss of hydrogen. Analysis results indicate that the number of vent cycles significantly decreases from 62 to 21 when tank pressure control increases from 6.9 to 20.4 kPa. Also, duration of vent cycle increases from 63 to 152 and cycle duration decreases from 3920 to 3200 s. Further, the analysis result suggests that LH2 evaporation loss per day decreases from 0.17 to 0.14%. Based on the results of analysis, TVS is found effective in controlling the propellant tank pressure in zero gravity.
Thermodynamic study of selected monoterpenes II
International Nuclear Information System (INIS)
Štejfa, Vojtěch; Fulem, Michal; Růžička, Květoslav; Červinka, Ctirad
2014-01-01
Highlights: • (−)-Borneol, (−)-camphor, (±)-camphene, and (+)-fenchone were studied. • New thermodynamic data were measured and calculated. • Most of thermodynamic data are reported for the first time. - Abstract: A thermodynamic study of selected monoterpenes, (−)-borneol, (−)-camphor, (±)-camphene, and (+)-fenchone is presented in this work. The vapor pressure measurements were performed using the static method over the environmentally important temperature range from (238 to 308) K. Heat capacities of condensed phases were measured by Tian–Calvet calorimetry in the temperature interval from (258 to 355) K. The phase behavior was investigated by differential scanning calorimetry (DSC) from subambient temperatures up to the fusion temperatures. The thermodynamic properties in the ideal-gas state were calculated by combining statistical thermodynamic and density functional theory (DFT) calculations. Calculated ideal-gas heat capacities and experimental data for vapor pressures and condensed phase heat capacities were treated simultaneously to obtain a consistent thermodynamic description
Miao, Yurun; Li, Huayang; Wang, Hongjuan; He, Kaihua; Wang, Qingbo
2018-02-01
First principles and quasi-harmonic Debye model have been used to study the thermodynamic properties, enthalpies, electronic and optical properties of MgO up to the core-mantle boundary (CMB) condition (137 GPa and 3700 K). Thermodynamic properties calculation includes thermal expansion coefficient and capacity, which have been studied up to the CMB pressure (137 GPa) and temperature (3700 K) by the Debye model with generalized gradient approximation (GGA) and local-density approximation (LDA). First principles with hybrid functional method (PBE0) has been used to calculate the electronic and optical properties under pressure up to 137 GPa and 0 K. Our results show the Debye model with LDA and first principles with PBE0 can provide accurate thermodynamic properties, enthalpies, electronic and optical properties. Calculated enthalpies show that MgO keep NaCl (B1) structure up to 137 GPa. And MgO is a direct bandgap insulator with a 7.23 eV calculated bandgap. The bandgap increased with increasing pressure, which will induce a blue shift of optical properties. We also calculated the density of states (DOS) and discussed the relation between DOS and band, optical properties. Equations were used to fit the relations between pressure and bandgaps, absorption coefficient (α(ω)) of MgO. The equations can be used to evaluate pressure after careful calibration. Our calculations can not only be used to identify some geological processes, but also offer a reference to the applications of MgO in the future.
Granet, Irving
2014-01-01
Fundamental ConceptsIntroductionThermodynamic SystemsTemperatureForce and MassElementary Kinetic Theory of GasesPressureReviewKey TermsEquations Developed in This ChapterQuestionsProblemsWork, Energy, and HeatIntroductionWorkEnergyInternal EnergyPotential EnergyKinetic EnergyHeatFlow WorkNonflow WorkReviewKey TermsEquations Developed in This ChapterQuestionsProblemsFirst Law of ThermodynamicsIntroductionFirst Law of ThermodynamicsNonflow SystemSteady-Flow SystemApplications of First Law of ThermodynamicsReviewKey TermsEquations Developed in This ChapterQuestionsProblemsThe Second Law of ThermodynamicsIntroductionReversibility-Second Law of ThermodynamicsThe Carnot CycleEntropyReviewKey TermsEquations Developed in This ChapterQuestionsProblemsProperties of Liquids and GasesIntroductionLiquids and VaporsThermodynamic Properties of SteamComputerized PropertiesThermodynamic DiagramsProcessesReviewKey TermsEquations Developed in This ChapterQuestionsProblemsThe Ideal GasIntroductionBasic ConsiderationsSpecific Hea...
Thermodynamic study of selected monoterpenes
Czech Academy of Sciences Publication Activity Database
Štejfa, V.; Fulem, Michal; Růžička, K.; Červinka, C.; Rocha, M.A.A.; Santos, L.M.N.B.F.; Schröder, B.
2013-01-01
Roč. 60, MAY (2013), 117-125 ISSN 0021-9614 Institutional support: RVO:68378271 Keywords : monoterpenes * pinene * vapor pressure * heat capacity * vaporization and sublimation enthalpy * ideal - gas thermodynamic Subject RIV: BJ - Thermodynamics Impact factor: 2.423, year: 2013
Thermodynamic and transport properties of gaseous tetrafluoromethane in chemical equilibrium
Hunt, J. L.; Boney, L. R.
1973-01-01
Equations and in computer code are presented for the thermodynamic and transport properties of gaseous, undissociated tetrafluoromethane (CF4) in chemical equilibrium. The computer code calculates the thermodynamic and transport properties of CF4 when given any two of five thermodynamic variables (entropy, temperature, volume, pressure, and enthalpy). Equilibrium thermodynamic and transport property data are tabulated and pressure-enthalpy diagrams are presented.
Directory of Open Access Journals (Sweden)
Saidi Temitope Sabitu
2012-06-01
Full Text Available The influence of transition metal oxide catalysts (ZrO2, CeO2, Fe3O4 and Nb2O5 on the hydrogen desorption kinetics of MgH2 was investigated using constant pressure thermodynamic driving forces in which the ratio of the equilibrium plateau pressure (pm to the opposing plateau (pop was the same in all the reactions studied. The results showed Nb2O5 to be vastly superior to other catalysts for improving the thermodynamics and kinetics of MgH2. The modeling studies showed reaction at the phase boundary to be likely process controlling the reaction rates of all the systems studied.
Modern engineering thermodynamics
Balmer, Robert T
2010-01-01
Designed for use in a standard two-semester engineering thermodynamics course sequence. The first half of the text contains material suitable for a basic Thermodynamics course taken by engineers from all majors. The second half of the text is suitable for an Applied Thermodynamics course in mechanical engineering programs. The text has numerous features that are unique among engineering textbooks, including historical vignettes, critical thinking boxes, and case studies. All are designed to bring real engineering applications into a subject that can be somewhat abstract and mathematica
International Nuclear Information System (INIS)
Feng, Hongcui; Zhong, Wei; Wu, Yanling; Tong, Shuiguang
2014-01-01
Highlights: • A general model of multi-pressure HRSG based on heat exchangers layout is built. • The minimum temperature difference is introduced to replace pinch point analysis. • Effects of layout on dual pressure HRSG thermodynamic performances are analyzed. - Abstract: Changes of heat exchangers layout in heat recovery steam generator (HRSG) will modify the amount of waste heat recovered from flue gas; this brings forward a desire for the optimization of the design of HRSG. In this paper the model of multi-pressure HRSG is built, and an instance of a dual pressure HRSG under three different layouts of Taihu Boiler Co., Ltd. is discussed, with specified values of inlet temperature, mass flow rate, composition of flue gas and water/steam parameters as temperature, pressure etc., steam mass flow rate and heat efficiency of different heat exchangers layout of HRSG are analyzed. This analysis is based on the laws of thermodynamics and incorporated into the energy balance equations for the heat exchangers. In the conclusion, the results of the steam mass flow rate, heat efficiency obtained for three heat exchangers layout of HRSGs are compared. The results show that the optimization of heat exchangers layout of HRSGs has a great significance for waste heat recovery and energy conservation
Borysow, Jacek; del Rosso, Leonardo; Celli, Milva; Moraldi, Massimo; Ulivi, Lorenzo
2014-04-01
We have measured the Raman Q-branch of hydrogen in a solution with water at a temperature of about 280 K and at pressures from 20 to 200 MPa. From a least-mean-square fitting analysis of the broad Raman Q-branch, we isolated the contributions from the four lowest individual roto-vibrational lines. The vibrational lines were narrower than the pure rotational Raman lines of hydrogen dissolved in water measured previously, but significantly larger than in the gas. The separations between these lines were found to be significantly smaller than in gaseous hydrogen and their widths were slightly increasing with pressure. The lines were narrowing with increasing rotational quantum number. The Raman frequencies of all roto-vibrational lines were approaching the values of gas phase hydrogen with increasing pressure. Additionally, from the comparison of the integrated intensity signal of Q-branch of hydrogen to the integrated Raman signal of the water bending mode, we have obtained the concentration of hydrogen in a solution with water along the 280 K isotherm. Hydrogen solubility increases slowly with pressure, and no deviation from a smooth behaviour was observed, even reaching thermodynamic conditions very close to the transition to the stable hydrogen hydrate. The analysis of the relative hydrogen concentration in solution on the basis of a simple thermodynamic model has allowed us to obtain the molar volume for the hydrogen gas/water solution. Interestingly, the volume relative to one hydrogen molecule in solution does not decrease with pressure and, at high pressure, is larger than the volume pertinent to one molecule of water. This is in favour of the theory of hydrophobic solvation, for which a larger and more stable structure of the water molecules is expected around a solute molecule.
REA, The Editors of
2012-01-01
REA's Essentials provide quick and easy access to critical information in a variety of different fields, ranging from the most basic to the most advanced. As its name implies, these concise, comprehensive study guides summarize the essentials of the field covered. Essentials are helpful when preparing for exams, doing homework and will remain a lasting reference source for students, teachers, and professionals. Thermodynamics I includes review of properties and states of a pure substance, work and heat, energy and the first law of thermodynamics, entropy and the second law of thermodynamics
Zorębski, Edward; Zorębski, Michał
2014-01-01
The so-called Beyer nonlinearity parameter B/A is calculated for 1,2- and 1,3-propanediol, 1,2-, 1,3-, and 1,4-butanediol, as well as 2-methyl-2,4-pentanediol by means of a thermodynamic method. The calculations are made for temperatures from (293.15 to 318.15) K and pressures up to 100 MPa. The decrease in B/A values with the increasing pressure is observed. In the case of 1,3-butanediol, the results are compared with corresponding literature data. The consistency is very satisfactory. A simple relationship between the internal pressure and B/A nonlinearity parameter has also been studied. Copyright © 2013 Elsevier B.V. All rights reserved.
Modeling ARRM Xenon Tank Pressurization Using 1D Thermodynamic and Heat Transfer Equations
Gilligan, Patrick; Tomsik, Thomas
2016-01-01
As a first step in understanding what ground support equipment (GSE) is required to provide external cooling during the loading of 5,000 kg of xenon into 4 aluminum lined composite overwrapped pressure vessels (COPVs), a modeling analysis was performed using Microsoft Excel. The goals of the analysis were to predict xenon temperature and pressure throughout loading at the launch facility, estimate the time required to load one tank, and to get an early estimate of what provisions for cooling xenon might be needed while the tanks are being filled. The model uses the governing thermodynamic and heat transfer equations to achieve these goals. Results indicate that a single tank can be loaded in about 15 hours with reasonable external coolant requirements. The model developed in this study was successfully validated against flight and test data. The first data set is from the Dawn mission which also utilizes solar electric propulsion with xenon propellant, and the second is test data from the rapid loading of a hydrogen cylindrical COPV. The main benefit of this type of model is that the governing physical equations using bulk fluid solid temperatures can provide a quick and accurate estimate of the state of the propellant throughout loading which is much cheaper in terms of computational time and licensing costs than a Computation Fluid Dynamics (CFD) analysis while capturing the majority of the thermodynamics and heat transfer.
Erum, Nazia; Iqbal, Muhammad Azhar
2017-11-01
The structural, electronic, elastic, optical and thermodynamic properties of cubic fluoroperovskite SrLiF3 at ambient and high-pressure are investigated by using first-principles total energy calculations within the framework of Generalized Gradient Approximation (GGA), combined with Quasi-harmonic Debye model in which the phonon effects are considered. The pressure effects are determined in the range of 0-50 GPa, in which cubic stability of SrLiF3 fluoroperovskite remains valid. The computed lattice parameters agree well with experimental and previous theoretical results. Decrease in lattice constant and bonds length is observed with the increase in pressure from 0 to 50 GPa. The effect of increase in pressure on electronic band structure calculations with GGA and GGA plus Tran-Blaha modified Becke-Johnson (TB-mBJ) potential reveals a predominant characteristic associated with widening of bandgap. The influence of pressure on elastic constants and their related mechanical parameters have been discussed in detail. All the calculated optical properties such as the complex dielectric function Ԑ(ω), optical conductivity σ(ω), energy loss function L(ω), absorption coefficient α(w), refractive index n (ω), reflectivity R (ω), and effective number of electrons neff, via sum rules shift towards the higher energies under the application of pressure. Moreover, important thermodynamic properties heat capacities (Cp and Cv), volume expansion coefficient (α), and Debye temperature (θD) are predicted successfully in the wide temperature and pressure ranges.
International Nuclear Information System (INIS)
Naemi, Sanaz; Saffar-Avval, Majid; Behboodi Kalhori, Sahand; Mansoori, Zohreh
2013-01-01
The thermodynamic and thermoeconomic analyses are investigated to achieve the optimum operating parameters of a dual pressure heat recovery steam generator (HRSG), coupled with a heavy duty gas turbine. In this regard, the thermodynamic objective function including the exergy waste and the exergy destruction, is defined in such a way to find the optimum pinch point, and consequently to minimize the objective function by using non-dimensional operating parameters. The results indicated that, the optimum pinch point from thermodynamic viewpoint is 2.5 °C and 2.1 °C for HRSGs with live steam at 75 bar and 90 bar respectively. Since thermodynamic analysis is not able to consider economic factors, another objective function including annualized installation cost and annual cost of irreversibilities is proposed. To find the irreversibility cost, electricity price and also fuel price are considered independently. The optimum pinch point from thermoeconomic viewpoint on basis of electricity price is 20.6 °C (75 bar) and 19.2 °C (90 bar), whereas according to the fuel price it is 25.4 °C and 23.7 °C. Finally, an extensive sensitivity analysis is performed to compare optimum pinch point for different electricity and fuel prices. -- Highlights: ► Presenting thermodynamic and thermoeconomic optimization of a heat recovery steam generator. ► Defining an objective function consists of exergy waste and exergy destruction. ► Defining an objective function including capital cost and cost of irreversibilities. ► Obtaining the optimized operating parameters of a dual pressure heat recovery boiler. ► Computing the optimum pinch point using non-dimensional operating parameters
Sokolova, Tatiana S.; Dorogokupets, Peter I.; Dymshits, Anna M.; Danilov, Boris S.; Litasov, Konstantin D.
2016-09-01
We present Microsoft Excel spreadsheets for calculation of thermodynamic functions and P-V-T properties of MgO, diamond and 9 metals, Al, Cu, Ag, Au, Pt, Nb, Ta, Mo, and W, depending on temperature and volume or temperature and pressure. The spreadsheets include the most common pressure markers used in in situ experiments with diamond anvil cell and multianvil techniques. The calculations are based on the equation of state formalism via the Helmholtz free energy. The program was developed using Visual Basic for Applications in Microsoft Excel and is a time-efficient tool to evaluate volume, pressure and other thermodynamic functions using T-P and T-V data only as input parameters. This application is aimed to solve practical issues of high pressure experiments in geosciences and mineral physics.
Institute of Scientific and Technical Information of China (English)
LIU Zhong-Li; CHENG Yan; TAN Ni-Na; GOU Qing-Quan
2006-01-01
The thermodynamic properties of LiBC are investigated by using the full-potential linearized muffin-tin orbital method (FP-LMTO) within the frame of density functional theory (DFT) and using the quasi-harmonic Debye model. The dependencies of the normalized lattice parameters a/a0 and c/c0, the ratio (c/a)/2, the normalized primitive volume V/V0 on pressure and temperature are successfully obtained. It is found that the interlayer covalent interactions (Li-B bonds or Li-C bonds) are more sensitive to temperature and pressure than intralayer ones (B-C bonds), as gives rise to the extreme lattice anisotropy in the bulk hcp LiBC.
Modern Thermodynamics Based on the Extended Carnot Theorem
Wang, Jitao
2012-01-01
"Modern Thermodynamics- Based on the Extended Carnot Theorem" provides comprehensive definitions and mathematical expressions of both classical and modern thermodynamics. The goal is to develop the fundamental theory on an extended Carnot theorem without incorporating any extraneous assumptions. In particular, it offers a fundamental thermodynamic and calculational methodology for the synthesis of low-pressure diamonds. It also discusses many "abnormal phenomena", such as spiral reactions, cyclic reactions, chemical oscillations, low-pressure carat-size diamond growth, biological systems, and more. The book is intended for chemists and physicists working in thermodynamics, chemical thermodynamics, phase diagrams, biochemistry and complex systems, as well as graduate students in these fields. Jitao Wang is a professor emeritus at Fudan University, Shanghai, China.
Thermodynamic characteristics of a novel supercritical compressed air energy storage system
International Nuclear Information System (INIS)
Guo, Huan; Xu, Yujie; Chen, Haisheng; Zhou, Xuezhi
2016-01-01
Highlights: • A novel supercritical compressed air energy storage system is proposed. • The energy density of SC-CAES is approximately 18 times larger than that of conventional CAES. • The characteristic of thermodynamics and exergy destruction is comprehensively analysed. • The corresponding optimum relationship between charging and discharging pressure is illustrated. • A turning point of efficiency is indicated because of the heat transfer of crossing the critical point. - Abstract: A novel supercritical compressed air energy storage (SC-CAES) system is proposed by our team to solve the problems of conventional CAES. The system eliminates the dependence on fossil fuel and large gas-storage cavern, as well as possesses the advantages of high efficiency by employing the special properties of supercritical air, which is significant for the development of electrical energy storage. The thermodynamic model of the SC-CAES system is built, and the thermodynamic characters are revealed. Through the exergy analysis of the system, the processes of the larger exergy destruction include compression, expansion, cold storage/heat exchange and throttle. Furthermore, sensitivity analysis shows that there is an optimal energy releasing pressure to make the system achieve the highest efficiency when energy storage pressure is constant. The efficiency of SC-CAES is expected to reach about 67.41% when energy storage pressure and energy releasing pressure are 120 bar and 95.01 bar, respectively. At the same time, the energy density is 18 times larger than that of conventional CAES. Sensitivity analysis also shows the change laws of system efficiency varying with other basic system parameters. The study provides support for the design and engineering of SC-CAES.
Peaceful nuclear explosions and thermodynamics
International Nuclear Information System (INIS)
Prieto, F.E.
1975-01-01
Some theoretical advances in the thermodynamics of very high pressures are reviewed. A universal (system-independent) formulation of the thermodynamics is sketched, and some of the equations more frequently used are written in system-independent form. Among these equations are: Hugoniot pressure and temperature as functions of volume; the Mie-Gruneisen equation; and an explicit form for the equation of state. It is also shown that this formalism can be used to interpret and predict results from peaceful nuclear explosions. (author)
Allison, C. M.; Roggensack, K.; Clarke, A. B.
2017-12-01
Volatile solubility in magmas is dependent on several factors, including composition and pressure. Mafic (basaltic) magmas with high concentrations of alkali elements (Na and K) are capable of dissolving larger quantities of H2O and CO2 than low-alkali basalt. The exsolution of abundant gases dissolved in alkali-rich mafic magmas can contribute to large explosive eruptions. Existing volatile solubility models for alkali-rich mafic magmas are well calibrated below 200 MPa, but at greater pressures the experimental data is sparse. To allow for accurate interpretation of mafic magmatic systems at higher pressures, we conducted a set of mixed H2O-CO2 volatile solubility experiments between 400 and 600 MPa at 1200 °C in six mafic compositions with variable alkali contents. Compositions include magmas from volcanoes in Italy, Antarctica, and Arizona. Results from our experiments indicate that existing volatile solubility models for alkali-rich mafic magmas, if extrapolated beyond their calibrated range, over-predict CO2 solubility at mid-crustal pressures. Physically, these results suggest that volatile exsolution can occur at deeper levels than what can be resolved from the lower-pressure experimental data. Existing thermodynamic models used to calculate volatile solubility at different pressures require two experimentally derived parameters. These parameters represent the partial molar volume of the condensed volatile species in the melt and its equilibrium constant, both calculated at a standard temperature and pressure. We derived these parameters for each studied composition and the corresponding thermodynamic model shows good agreement with the CO2 solubility data of the experiments. A general alkali basalt solubility model was also constructed by establishing a relationship between magma composition and the thermodynamic parameters. We utilize cation fractions from our six compositions along with four compositions from the experimental literature in a linear
Thermodynamic volume and the extended Smarr relation
Energy Technology Data Exchange (ETDEWEB)
Hyun, Seungjoon; Jeong, Jaehoon; Park, Sang-A; Yi, Sang-Heon [Department of Physics, College of Science, Yonsei University,Seoul 120-749 (Korea, Republic of)
2017-04-10
We continue to explore the scaling transformation in the reduced action formalism of gravity models. As an extension of our construction, we consider the extended forms of the Smarr relation for various black holes, adopting the cosmological constant as the bulk pressure as in some literatures on black holes. Firstly, by using the quasi-local formalism for charges, we show that, in a general theory of gravity, the volume in the black hole thermodynamics could be defined as the thermodynamic conjugate variable to the bulk pressure in such a way that the first law can be extended consistently. This, so called, thermodynamic volume can be expressed explicitly in terms of the metric and field variables. Then, by using the scaling transformation allowed in the reduced action formulation, we obtain the extended Smarr relation involving the bulk pressure and the thermodynamic volume. In our approach, we do not resort to Euler’s homogeneous scaling of charges while incorporating the would-be hairy contribution without any difficulty.
Modern thermodynamics. Based on the extended Carnot theorem
Energy Technology Data Exchange (ETDEWEB)
Wang, Jitao [Fudan Univ., Shanghai (China). Microelectronics Dept.
2011-07-01
''Modern Thermodynamics- Based on the Extended Carnot Theorem'' provides comprehensive definitions and mathematical expressions of both classical and modern thermodynamics. The goal is to develop the fundamental theory on an extended Carnot theorem without incorporating any extraneous assumptions. In particular, it offers a fundamental thermodynamic and calculational methodology for the synthesis of low-pressure diamonds. It also discusses many ''abnormal phenomena'', such as spiral reactions, cyclic reactions, chemical oscillations, low-pressure carat-size diamond growth, biological systems, and more. The book is intended for chemists and physicists working in thermodynamics, chemical thermodynamics, phase diagrams, biochemistry and complex systems, as well as graduate students in these fields. Jitao Wang is a professor emeritus at Fudan University, Shanghai, China. (orig.)
Erum, Nazia; Azhar Iqbal, Muhammad
2017-12-01
The effect of pressure variation on structural, electronic, elastic, mechanical, optical and thermodynamic characteristics of cubic SrNaF3 fluoroperovskite have been investigated by employing first-principles method within the framework of gradient approximation (GGA). For the total energy calculations, we have used the full-potential linearized augmented plane wave (FP-LAPW) method. Thermodynamic properties are computed in terms of quasi-harmonic Debye model. The pressure effects are determined in the range of 0-25 GPa, in which mechanical stability of SrNaF3 fluoroperovskite remains valid. A prominent decrease in lattice constant and bonds length is observed with the increase in pressure from 0 to 25 GPa. The effect of increase in pressure on band structure calculations with GGA and GGA plus Tran-Blaha modified Becke-Johnson (TB-mBJ) potential reveals a predominant characteristic associated with widening of bandgap. The influence of pressure on set of isotropic elastic parameters and their related properties are numerically estimated for SrNaF3 polycrystalline aggregate. Apart of linear dependence of elastic coefficients, transition from brittle to ductile behavior is observed as pressure is increased from 0 to 25 GPa. We have successfully obtained variation of lattice constant, volume expansion, bulk modulus, Debye temperature and specific heat capacities with pressure and temperature in the range of 0-25 GPa and 0-600 K. All the calculated optical properties such as the complex dielectric function ɛ(ω), optical conductivity σ(ω), energy loss function L(ω), absorption coefficient α(w), refractive index n(ω), reflectivity R(ω), and effective number of electrons n eff, via sum rules shift towards the higher energies under the application of pressure.
International Nuclear Information System (INIS)
Phan, Anh Thu; Paek, Min-Kyu; Kang, Youn-Bae
2014-01-01
In order to provide an efficient tool to design alloy chemistry and processing conditions for high-strength, lightweight steel, an investigation of the Fe–Al–C ternary system was carried out by experimental phase diagram measurement and a CALPHAD thermodynamic analysis. Discrepancies between previously available experimental results and thermodynamic calculations were identified. The Fe–Al sub-binary system was re-optimized in order to obtain an accurate description of the liquid phase, while Gibbs energies of solid phases were mainly taken from a previous thermodynamic modeling. Phase equilibria among face-centered cubic (fcc)/body-centered cubic (bcc)/graphite/κ-carbide/liquid phases in the Fe–Al–C system in the temperature range from 1000 to 1400 °C were obtained by chemical equilibration followed by quenching, and subsequent composition analysis using electron probe microanalysis/inductively coupled plasma spectroscopy. By merging the revised Fe–Al binary description with existing Fe–C and Al–C binary descriptions, a complete thermodynamic description of the Fe–Al–C system was obtained in the present study. The modified quasi-chemical model in the pair approximation was used to model the liquid phase, while solid solutions were modeled using compound energy formalism. A2/B2 order/disorder transition in the bcc phase was taken into account. Compared with previously known experiments/thermodynamic modeling, a better agreement was obtained in the present study, regarding the stable region of fcc and the solidification thermal peak of a ternary alloy near the liquidus temperature. The obtained thermodynamic description also reproduced various types of experimental data in the Fe–Al–C system such as isothermal sections, vertical sections, liquidus projection, etc. The solidification of various steel grades was predicted and discussed
Tables of thermodynamic properties of sodium
International Nuclear Information System (INIS)
Fink, J.K.
1982-06-01
The thermodynamic properties of saturated sodium, superheated sodium, and subcooled sodium are tabulated as a function of temperature. The temperature ranges are 380 to 2508 K for saturated sodium, 500 to 2500 K for subcooled sodium, and 400 to 1600 K for superheated sodium. Tabulated thermodynamic properties are enthalpy, heat capacity, pressure, entropy, density, instantaneous thermal expansion coefficient, compressibility, and thermal pressure coefficient. Tables are given in SI units and cgs units
Casimir effect and thermodynamics of horizon instabilities
International Nuclear Information System (INIS)
Hartnoll, Sean A.
2004-01-01
We propose a dual thermodynamic description of a classical instability of generalized black hole spacetimes. From a thermodynamic perspective, the instability is due to negative compressibility in regions where the Casimir pressure is large. The argument indicates how the correspondence between thermodynamic and classical instability for horizons may be extended to cases without translational invariance
International Nuclear Information System (INIS)
Zhou Mu; Wang Feng; Zheng Zhou; Liu Xiankun; Jiang Tao
2013-01-01
The elastic and thermodynamic properties of UO 2 under extreme physical condition are studied by using the density functional theory and quasi-harmonic Debye model. Results show that UO 2 is still stable ionic crystal under high temperatures, and pressures. Tetragonal shear constant is steady under high pressures and temperatures, while elastic constant C 44 is stable under high temperatures, but rises with pressure sharply. Bulk modulus, shear modulus and Young's modulus increase with pressure rapidly, but temperature would not cause evident debasement of the moduli, all of which indicate that UO 2 has excellent mechanical properties. Heat capacity of different pressures increases with temperature and is close to the Dulong-Petit limit near 1000 K. Debye temperature decreases with temperature, and increases with pressure. Under low pressure, thermal expansion coefficient raises with temperature rapidly, and then gets slow at higher pressure and temperature. Besides, the thermal expansion coefficient of UO 2 is much lower than that of other nuclear materials. (authors)
Thermodynamic modeling of hydrogen storage capacity in Mg-Na alloys.
Abdessameud, S; Mezbahul-Islam, M; Medraj, M
2014-01-01
Thermodynamic modeling of the H-Mg-Na system is performed for the first time in this work in order to understand the phase relationships in this system. A new thermodynamic description of the stable NaMgH3 hydride is performed and the thermodynamic models for the H-Mg, Mg-Na, and H-Na systems are reassessed using the modified quasichemical model for the liquid phase. The thermodynamic properties of the ternary system are estimated from the models of the binary systems and the ternary compound using CALPHAD technique. The constructed database is successfully used to reproduce the pressure-composition isotherms for MgH2 + 10 wt.% NaH mixtures. Also, the pressure-temperature equilibrium diagram and reaction paths for the same composition are predicted at different temperatures and pressures. Even though it is proved that H-Mg-Na does not meet the DOE hydrogen storage requirements for onboard applications, the best working temperatures and pressures to benefit from its full catalytic role are given. Also, the present database can be used for thermodynamic assessments of higher order systems.
Energy Technology Data Exchange (ETDEWEB)
Peleties, F. [Department of Chemical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ (United Kingdom); Segovia, J.J. [Grupo de Termodinamica y Calibracion (TERMOCAL), Dpto. Ingenieria Energetica y Fluidomecanica, E.T.S. de Ingenieros Industriales, Universidad de Valladolid, E-47011 Valladolid (Spain); Trusler, J.P.M., E-mail: m.trusler@imperial.ac.u [Department of Chemical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ (United Kingdom); Vega-Maza, D. [Grupo de Termodinamica y Calibracion (TERMOCAL), Dpto. Ingenieria Energetica y Fluidomecanica, E.T.S. de Ingenieros Industriales, Universidad de Valladolid, E-47011 Valladolid (Spain)
2010-05-15
We report measurements of the thermodynamic properties of liquid di-isodecyl phthalate (DIDP) and an equation of state determined therefrom. The speed of sound in DIDP was measured at temperatures between (293.15 and 413.15) K and a pressures between (0.1 and 140) MPa with a relative uncertainty of 0.1%. In addition, the isobaric specific heat capacity was measured at temperatures between (293.15 and 423.15) K at a pressure of 0.1 MPa with a relative uncertainty of 1%, and the density was measured at temperatures between (273.15 and 413.15) K at a pressure of 0.1 MPa with a relative uncertainty of 0.015%. The thermodynamic properties of DIDP were obtained from the measured speeds of sound by thermodynamic integration starting from the initial values of density and isobaric specific heat capacity obtained experimentally. The results have been represented by a new equation of state containing nine parameters with an uncertainty in density not worse than 0.025%. Comparisons with literature data are made.
International Nuclear Information System (INIS)
Peleties, F.; Segovia, J.J.; Trusler, J.P.M.; Vega-Maza, D.
2010-01-01
We report measurements of the thermodynamic properties of liquid di-isodecyl phthalate (DIDP) and an equation of state determined therefrom. The speed of sound in DIDP was measured at temperatures between (293.15 and 413.15) K and a pressures between (0.1 and 140) MPa with a relative uncertainty of 0.1%. In addition, the isobaric specific heat capacity was measured at temperatures between (293.15 and 423.15) K at a pressure of 0.1 MPa with a relative uncertainty of 1%, and the density was measured at temperatures between (273.15 and 413.15) K at a pressure of 0.1 MPa with a relative uncertainty of 0.015%. The thermodynamic properties of DIDP were obtained from the measured speeds of sound by thermodynamic integration starting from the initial values of density and isobaric specific heat capacity obtained experimentally. The results have been represented by a new equation of state containing nine parameters with an uncertainty in density not worse than 0.025%. Comparisons with literature data are made.
Wang, Ning; Zhou, Jin; Pan, Yu; Wang, Hui
2014-02-01
Active cooling with endothermic hydrocarbon fuel is proved to be one of the most promising approaches to solve the thermal problem for hypersonic aircraft such as scramjet. The flow patterns of two-phase flow inside the cooling channels have a great influence on the heat transfer characteristics. In this study, phase transition processes of RP-3 kerosene flowing inside a square quartz-glass tube were experimentally investigated. Three distinct phase transition phenomena (liquid-gas two phase flow under sub-critical pressures, critical opalescence under critical pressure, and corrugation under supercritical pressures) were identified. The conventional flow patterns of liquid-gas two phase flow, namely bubble flow, slug flow, churn flow and annular flow are observed under sub-critical pressures. Dense bubble flow and dispersed flow are recognized when pressure is increased towards the critical pressure whilst slug flow, churn flow and annular flow disappear. Under critical pressure, the opalescence phenomenon is observed. Under supercritical pressures, no conventional phase transition characteristics, such as bubbles are observed. But some kind of corrugation appears when RP-3 transfers from liquid to supercritical. The refraction index variation caused by sharp density gradient near the critical temperature is thought to be responsible for this corrugation.
Energy Technology Data Exchange (ETDEWEB)
Seddik, T. [Laboratoire de Physique Quantique et de Modélisation Mathématique, Université de Mascara, 29000 Mascara (Algeria); Khenata, R., E-mail: khenata_rabah@yahoo.fr [Laboratoire de Physique Quantique et de Modélisation Mathématique, Université de Mascara, 29000 Mascara (Algeria); Bouhemadou, A.; Guechi, N. [Laboratory for Developing New Materials and their Characterization, Department of Physics, Faculty of Science, University of Setif, 19000 Setif (Algeria); Sayede, A. [Université Lille Nord de France, F-59000 Lille (France); Université-Artois, UCCS, F-62300 Lens (France); CNRS, UMR 8181, F-59650 Villeneuve d’Ascq (France); Varshney, D. [Materials Science Laboratory, School of Physics, Vigyan Bhavan, Devi Ahilya University, Khandwa Road Campus, Indore 452001, Madhya Pradesh (India); Al-Douri, Y. [Institute of Nono Electronic Engineering, University Malaysia Perlis, 01000 Kangar, Perlis (Malaysia); Reshak, A.H. [Institute of Complex Systems, FFPW, CENAKVA, University of South Bohemia in CB, Nove Hrady 37333 (Czech Republic); Center of Excellence Geopolymer and Green Technology, School of Material Engineering, University Malaysia Perlis, 01007 Kangar, Perlis (Malaysia); Bin-Omran, S. [Department of Physics and Astronomy, Faculty of Science, King Saud University, PO Box 2455, Riyadh 11451 (Saudi Arabia)
2013-11-01
The full potential linearized augmented plane wave method within the framework of density functional theory is employed to investigate the structural, thermodynamic and elastic properties of the yttrium chalcogenides (YX: X=S, Se, and Te) in their low-pressure phase (Fm3{sup ¯}m) and high-pressure phase (Pm3{sup ¯}m). The exchange-correlation potential is treated with the generalized gradient approximation of Perdew–Burke–Ernzerhof (GGA-PBE). Temperature dependence of the volume and both adiabatic and isothermal bulk moduli is predicted for a temperature range from 0to1200K for the both phases of the herein considered materials. Furthermore, we have analyzed the thermodynamic properties such as the heat capacities, C{sub V} and C{sub P}, thermal expansion, α, and Debye temperature, Θ{sub D,} under variable pressure and temperature. We have calculated the isothermal elastic constants C{sub ij}{sup T} of the YX monochalcogenides in both NaCl-B1 and CsCl-B2 phases at zero pressure and a temperature range 0−1200K. The results show that rare earth yttrium monochalcogenides are mechanically stable at high temperature. The elastic anisotropy of all studied materials in the two phases has been studied using three different methods.
Pressure Injury Knowledge in Critical Care Nurses.
Miller, Donna M; Neelon, Lisa; Kish-Smith, Kathleen; Whitney, Laura; Burant, Christopher J
The purpose of this study was to identify pressure injury knowledge in critical care nurses related to prevention and staging following multimodal education initiatives. Postintervention descriptive study. The sample comprised 32 RNs employed in medical intensive care/coronary intensive care or surgical intensive care units. The study setting was a 237-bed Veterans Affairs acute care hospital in the Midwestern United States. Critical care RNs were asked to participate in this project over a 3-week period following a multimodal 2-year education initiative. Nurses completed the paper version of the 72-item Pieper-Zulkowski Pressure Ulcer Knowledge Test (PZ-PUKT) to determine pressure injury knowledge level. Calculated mean cumulative scores and subscores for items related to prevention and staging, respectively. Pearson correlations were used to examine associations between nursing staff characteristics and the PZ-PUKT prevention and staging scores. The cumulative score on the PZ-PUKT was 51.66 (72%); nurses with 5 to 10 years' experience had a higher mean score than nurses with experiences of 20 years or more (mean ± SD = 54.25 ± 4.37 vs 49.5 ± 7.12), but the difference was not statistically significant. Nurses scored higher on the staging system-related items as compared to the prevention-related items (81% vs 70%). Nurses achieved higher staging subscale scores if they were younger (r =-0.41, P < .05), had less experience (r =-0.43, P < .05), and if they worked in the medical intensive care unit (r = 0.37, P < .05). Study findings indicate gaps in knowledge related to pressure injury practice; participants had greater knowledge of staging rather than prevention. Cumulative and subscale findings can be used to direct educational efforts needed to improve and maintain an effective pressure injury prevention program.
Thermodynamic modeling of direct injection methanol fueled engines
International Nuclear Information System (INIS)
Shen Yuan; Bedford, Joshua; Wichman, Indrek S.
2009-01-01
In-cylinder pressure is an important parameter that is used to investigate the combustion process in internal combustion (IC) engines. In this paper, a thermodynamic model of IC engine combustion is presented and examined. A heat release function and an empirical conversion efficiency factor are introduced to solve the model. The pressure traces obtained by solving the thermodynamic model are compared with measured pressure data for a fully instrumented laboratory IC spark ignition (SI) engine. Derived scaling parameters for time to peak pressure, peak pressure, and maximum rate of pressure rise (among others) are developed and compared with the numerical simulations. The models examined here may serve as pedagogic tools and, when suitably refined, as preliminary design tools.
Effects of temperature and pressure on thermodynamic properties of Cd0.50 Zn0.50 Se alloy
Aarifeen, Najm ul; Afaq, A.
2017-09-01
Thermodynamic properties of \\text{C}{{\\text{d}}0.50} \\text{Z}{{\\text{n}}0.50} Se alloy are studied using quasi harmonic model for pressure range 0-10 GPa and temperature range 0-1000 K. The structural optimization is obtained by self consistent field calculations and full-potential linear muffin-tin orbital method with GGA+U as an exchange correlation functional where U=2.3427 eV is the hubbard potential. The effects of temperature and pressure on the bulk modulus, Helmholtz free energy, internal energy, entropy, Debye temperature, Grüneisen parameter, thermal expansion coefficient and heat capacities of the material are observed and discussed. The bulk modulus, Helmholtz free energy and Debye temperature are found to decrease with increasing temperature while there is an increasing behavior when the pressure rises. Whereas internal energy has increasing trend with rises in temperature and it almost remains insensitive to pressure. The entropy of the system increases (decreases) with a rise of pressure (temperature).
Concise chemical thermodynamics
Peters, APH
2010-01-01
EnergyThe Realm of ThermodynamicsEnergy BookkeepingNature's Driving ForcesSetting the Scene: Basic IdeasSystem and SurroundingsFunctions of StateMechanical Work and Expanding GasesThe Absolute Temperature Scale Forms of Energy and Their Interconversion Forms of Renewable Energy Solar Energy Wind Energy Hydroelectric Power Geothermal Energy Biomass Energy References ProblemsThe First Law of Thermodynamics Statement of the First Law Reversible Expansion of an Ideal GasConstant-Volume ProcessesConstant-Pressure ProcessesA New Function: EnthalpyRelationship between ?H and ?UUses and Conventions of
Thermodynamic Properties of Manganese and Molybdenum
International Nuclear Information System (INIS)
Desai, P.D.
1987-01-01
This work reviews and discusses the data on the various thermodynamic properties of manganese and molybdenum available through March 1985. These include heat capacity, enthalpy, enthalpy of transitions and melting, vapor pressure, and enthalpy of vaporization. The existing data have been critically evaluated and analyzed. The recommended values for the heat capacity, enthalpy, entropy, and Gibbs energy function from 0.5 to 2400 K for manganese and from 0.4 to 5000 K for molybdenum have been generated, as have heat capacity values for supercooled β-Mn and for γ-Mn below 298.15 K. The recommended values for vapor pressure cover the temperature range from 298.15 to 2400 K for manganese and from 298.15 to 5000 K for molybdenum. These values are referred to temperatures based on IPTS-1968. The uncertainties in the recommended values of the heat capacity range from +-3% to +-5% for manganese and from +-1.5% to +-3% for molybdenum
Thermodynamic properties of vanadium
International Nuclear Information System (INIS)
Desai, P.D.
1986-01-01
This work reviews and discusses the data and information on the various thermodynamic properties of vanadium available through March 1985. These include the heat capacity and enthalpy, enthalpy of melting, vapor pressure, and enthalpy of vaporization. The existing data have been critically evaluated and analyzed, and the recommended values for heat capacity, enthalpy, entropy, and Gibbs energy function covering the temperature range from 1 to 3800 K have been generated. These values are referred to tempertures based on IPTS-1968. The units used for various properties are joules per mole (J. mol - 1 ). The estimated uncertainties in the heat capacity are +/-3% below 15 K, +/-10% from 15 to 150 K, +/-3% from 150 to 298.15 K, +/-2% from 298.15 to 1000 K, +/-3% from 1000 to the melting point (2202 K), and +/-5% in the liquid region
Thermodynamics in Loop Quantum Cosmology
International Nuclear Information System (INIS)
Li, L.F.; Zhu, J.Y.
2009-01-01
Loop quantum cosmology (LQC) is very powerful to deal with the behavior of early universe. Moreover, the effective loop quantum cosmology gives a successful description of the universe in the semiclassical region. We consider the apparent horizon of the Friedmann-Robertson-Walker universe as a thermodynamical system and investigate the thermodynamics of LQC in the semiclassical region. The effective density and effective pressure in the modified Friedmann equation from LQC not only determine the evolution of the universe in LQC scenario but also are actually found to be the thermodynamic quantities. This result comes from the energy definition in cosmology (the Misner-Sharp gravitational energy) and is consistent with thermodynamic laws. We prove that within the framework of loop quantum cosmology, the elementary equation of equilibrium thermodynamics is still valid.
Erum, Nazia; Azhar Iqbal, Muhammad
2017-09-01
The effect of pressure variation on stability, structural parameters, elastic constants, mechanical, electronic and thermodynamic properties of cubic SrKF3 fluoroperovskite have been investigated by using the full-potential linearized augmented plane wave (FP-LAPW) method combined with Quasi-harmonic Debye model in which the phonon effects are considered. The calculated lattice parameters show a prominent decrease in lattice constant and bonds length with the increase in pressure. The application of pressure from 0 to 25 GPa reveals a predominant characteristic associated with widening of bandgap with GGA and GGA plus Tran-Blaha modified Becke-Johnson (TB-mBJ) potential. The influence of pressure on elastic constants and their related mechanical parameters have been discussed in detail. Apart of linear dependence of elastic coefficients, transition from brittle to ductile behavior is also observed at elevated pressure ranges. We have successfully computed variation of lattice constant, volume expansion, bulk modulus, Debye temperature and specific heat capacities at pressure and temperature in the range of 0-25 GPa and 0-600 K.
Thermodynamics of hairy black holes in Lovelock gravity
Hennigar, Robie A.; Tjoa, Erickson; Mann, Robert B.
2017-02-01
We perform a thorough study of the thermodynamic properties of a class of Lovelock black holes with conformal scalar hair arising from coupling of a real scalar field to the dimensionally extended Euler densities. We study the linearized equations of motion of the theory and describe constraints under which the theory is free from ghosts/tachyons. We then consider, within the context of black hole chemistry, the thermodynamics of the hairy black holes in the Gauss-Bonnet and cubic Lovelock theories. We clarify the connection between isolated critical points and thermodynamic singularities, finding a one parameter family of these critical points which occur for well-defined thermodynamic parameters. We also report on a number of novel results, including `virtual triple points' and the first example of a `λ-line' — a line of second order phase transitions — in black hole thermodynamics.
Tables of homogeneous equilibrium critical flow parameters for water in SI units
International Nuclear Information System (INIS)
Hall, D.G.; Czapary, L.S.
1980-09-01
This reference document presents tables and charts containing data calculated using the homogeneous equilibrium critical flow model (HEM). The ranges of stagnation state properties for which data are presented include: pressures from 2 to 22 120kPa, temperatures from 290 to 640 K, and thermodynamic qualities from 0 to 1
Outcalt, Stephanie L.; McLinden, Mark O.
1996-03-01
A modified Benedict-Webb-Rubin (MBWR) equation of state has been developed for R152a (1,1-difluoroethane). The correlation is based on a selection of available experimental thermodynamic property data. Single-phase pressure-volume-temperature (PVT), heat capacity, and sound speed data, as well as second virial coefficient, vapor pressure, and saturated liquid and saturated vapor density data, were used with multi-property linear least-squares fitting to determine the 32 adjustable coefficients of the MBWR equation. Ancillary equations representing the vapor pressure, saturated liquid and saturated vapor densities, and the ideal gas heat capacity were determined. Coefficients for the equation of state and the ancillary equations are given. Experimental data used in this work covered temperatures from 162 K to 453 K and pressures to 35 MPa. The MBWR equation established in this work may be used to predict thermodynamic properties of R152a from the triple-point temperature of 154.56 K to 500 K and for pressures up to 60 MPa except in the immediate vicinity of the critical point.
Nonlinear Dynamics and Nucleation Kinetics in Near-Critical Liquids
Patashinski, Alexander Z.; Ratner, Mark A.; Pines, Vladimir
1996-01-01
The objective of our study is to model the nonlinear behavior of a near-critical liquid following a rapid change of the temperature and/or other thermodynamic parameters (pressure, external electric or gravitational field). The thermodynamic critical point is manifested by large, strongly correlated fluctuations of the order parameter (particle density in liquid-gas systems, concentration in binary solutions) in the critical range of scales. The largest critical length scale is the correlation radius r(sub c). According to the scaling theory, r(sub c) increases as r(sub c) = r(sub 0)epsilon(exp -alpha) when the nondimensional distance epsilon = (T - T(sub c))/T(sub c) to the critical point decreases. The normal gravity alters the nature of correlated long-range fluctuations when one reaches epsilon approximately equal to 10(exp -5), and correspondingly the relaxation time, tau(r(sub c)), is approximately equal to 10(exp -3) seconds; this time is short when compared to the typical experimental time. Close to the critical point, a rapid, relatively small temperature change may perturb the thermodynamic equilibrium on many scales. The critical fluctuations have a hierarchical structure, and the relaxation involves many length and time scales. Above the critical point, in the one-phase region, we consider the relaxation of the liquid following a sudden temperature change that simultaneously violates the equilibrium on many scales. Below T(sub c), a non-equilibrium state may include a distribution of small scale phase droplets; we consider the relaxation of such a droplet following a temperature change that has made the phase of the matrix stable.
Thermodynamic Modeling of Hydrogen Storage Capacity in Mg-Na Alloys
Abdessameud, S.; Mezbahul-Islam, M.; Medraj, M.
2014-01-01
Thermodynamic modeling of the H-Mg-Na system is performed for the first time in this work in order to understand the phase relationships in this system. A new thermodynamic description of the stable NaMgH3 hydride is performed and the thermodynamic models for the H-Mg, Mg-Na, and H-Na systems are reassessed using the modified quasichemical model for the liquid phase. The thermodynamic properties of the ternary system are estimated from the models of the binary systems and the ternary compound using CALPHAD technique. The constructed database is successfully used to reproduce the pressure-composition isotherms for MgH2 + 10 wt.% NaH mixtures. Also, the pressure-temperature equilibrium diagram and reaction paths for the same composition are predicted at different temperatures and pressures. Even though it is proved that H-Mg-Na does not meet the DOE hydrogen storage requirements for onboard applications, the best working temperatures and pressures to benefit from its full catalytic role are given. Also, the present database can be used for thermodynamic assessments of higher order systems. PMID:25383361
Leege, Brian J.
The design of a liquid nitrogen vaporization and pressure building device that has zero product waste while recovering some of its stored energy is of interest for the cost reduction of nitrogen for use in industrial processes. Current devices may waste up to 30% of the gaseous nitrogen product by venting it to atmosphere. Furthermore, no attempt is made to recover the thermal energy available in the coldness of the cryogen. A seven step cycle with changing volumes and ambient heat addition is proposed, eliminating all product waste and providing the means of energy recovery from the nitrogen. This thesis discusses the new thermodynamic cycle and modeling as well as the mechanical design and testing of a prototype device. The prototype was able to achieve liquid nitrogen vaporization and pressurization up to 1000 psi, while full cycle validation is ongoing with promising initial results.
Thermodynamic properties of α-uranium
International Nuclear Information System (INIS)
Ren, Zhiyong; Wu, Jun; Ma, Rong; Hu, Guichao; Luo, Chao
2016-01-01
The lattice constants and equilibrium atomic volume of α-uranium were calculated by Density Functional Theory (DFT). The first principles calculation results of the lattice for α-uranium are in agreement with the experimental results well. The thermodynamic properties of α-uranium from 0 to 900 K and 0–100 GPa were calculated with the quasi-harmonic Debye model. Volume, bulk modulus, entropy, Debye temperature, thermal expansion coefficient and the heat capacity of α-uranium were calculated. The calculated results show that the bulk modulus and Debye temperature increase with the increasing pressure at a given temperature while decreasing with the increasing temperature at a given pressure. Volume, entropy, thermal expansion coefficient and the heat capacity decrease with the increasing pressure while increasing with the increasing temperature. The theoretical results of entropy, Debye temperature, thermal expansion coefficient and the heat capacity show good agreement with the general trends of the experimental values. The constant-volume heat capacity shows typical Debye T"3 power-law behavior at low temperature limit and approaches to the classical asymptotic Dulong-Petit limit at high temperature limit. - Highlights: • Thermodynamic properties of α-U were predicted systematically with quasi-harmonic Debye model. • Summarizations of the corresponding experimental and theoretical results have been made for the EOS and other thermodynamic parameters. • The calculated thermodynamic properties show good agreement with the experimental results in general trends.
Thermodynamic properties of α-uranium
Energy Technology Data Exchange (ETDEWEB)
Ren, Zhiyong; Wu, Jun; Ma, Rong; Hu, Guichao; Luo, Chao, E-mail: luochaoboss@sohu.com
2016-11-15
The lattice constants and equilibrium atomic volume of α-uranium were calculated by Density Functional Theory (DFT). The first principles calculation results of the lattice for α-uranium are in agreement with the experimental results well. The thermodynamic properties of α-uranium from 0 to 900 K and 0–100 GPa were calculated with the quasi-harmonic Debye model. Volume, bulk modulus, entropy, Debye temperature, thermal expansion coefficient and the heat capacity of α-uranium were calculated. The calculated results show that the bulk modulus and Debye temperature increase with the increasing pressure at a given temperature while decreasing with the increasing temperature at a given pressure. Volume, entropy, thermal expansion coefficient and the heat capacity decrease with the increasing pressure while increasing with the increasing temperature. The theoretical results of entropy, Debye temperature, thermal expansion coefficient and the heat capacity show good agreement with the general trends of the experimental values. The constant-volume heat capacity shows typical Debye T{sup 3} power-law behavior at low temperature limit and approaches to the classical asymptotic Dulong-Petit limit at high temperature limit. - Highlights: • Thermodynamic properties of α-U were predicted systematically with quasi-harmonic Debye model. • Summarizations of the corresponding experimental and theoretical results have been made for the EOS and other thermodynamic parameters. • The calculated thermodynamic properties show good agreement with the experimental results in general trends.
REA, The Editors of
2013-01-01
REA's Essentials provide quick and easy access to critical information in a variety of different fields, ranging from the most basic to the most advanced. As its name implies, these concise, comprehensive study guides summarize the essentials of the field covered. Essentials are helpful when preparing for exams, doing homework and will remain a lasting reference source for students, teachers, and professionals. Thermodynamics II includes review of thermodynamic relations, power and refrigeration cycles, mixtures and solutions, chemical reactions, chemical equilibrium, and flow through nozzl
The physical basis of thermodynamics with applications to chemistry
Richet, Pascal
2001-01-01
Given that thermodynamics books are not a rarity on the market, why would an additional one be useful? The answer is simple: at any level, thermodynamics is usually taught as a somewhat abstruse discipline where many students get lost in a maze of difficult concepts. However, thermodynamics is not as intricate a subject as most people feel. This book fills a niche between elementary textbooks and mathematically oriented treatises, and provides readers with a distinct approach to the subject. As indicated by the title, this book explains thermodynamic phenomena and concepts in physical terms before proceeding to focus on the requisite mathematical aspects. It focuses on the effects of pressure, temperature and chemical composition on thermodynamic properties and places emphasis on rapidly evolving fields such as amorphous materials, metastable phases, numerical simulations of microsystems and high-pressure thermodynamics. Topics like redox reactions are dealt with in less depth, due to the fact that there is a...
Energy Technology Data Exchange (ETDEWEB)
Coban, Cansu [Balikesir Univ. (Turkey). Dept. of Physics
2017-07-01
The pressure dependent behaviour of the structural, electronic, mechanical, vibrational, and thermodynamic properties of Pd{sub 2}TiX (X=Ga, In) Heusler alloys was investigated by ab initio calculations. The lattice constant, the bulk modulus and its first pressure derivative, the electronic band structure and the density of states (DOS), mechanical properties such as elastic constants, anisotropy factor, Young's modulus, etc., the phonon dispersion curves and phonon DOS, entropy, heat capacity, and free energy were obtained under pressure. It was determined that the calculated lattice parameters are in good agreement with the literature, the elastic constants obey the stability criterion, and the phonon dispersion curves have no negative frequency which shows that the compounds are stable. The band structures at 0, 50, and 70 GPa showed valence instability at the L point which explains the superconductivity in Pd{sub 2}TiX (X=Ga, In).
International Nuclear Information System (INIS)
Nabizadeh, H.
1977-01-01
Simulation of the thermohydraulic processes of the steady-state reactor operation with boiling water and typical fuel element geometries leads to considerable increase of the heat rates to be tranferred and thus to an increase of the experimental cost which can hardly be justified. By proper choice of a model fluid with low heat of evaporation the system parameters like pressure, temperature, and heat rate, while retaining the original geometry, may be reduced to a fraction of those of the original fluid water. This permits not only a decrease in experimental cost but also a modification of the existing calculation data under more favorable experimental conditions. Starting from these considerations the cooling medium R113 was used as model fluid in carrying out the experiments. The necessary knowledge of the thermodynamical laws of simularity, however, have to be determined first of all in simple geometries and the scaling factors are then derived from them. In this connection the following experimental studies have been carried out with R113: a) average volumetric steam quality; b) two-phase pressure drop; c) critical heat flux. (orig.) [de
International Nuclear Information System (INIS)
He, Yubao; Cao, Ruifeng; Huang, Hongyan; Qin, Jiang; Yu, Daren
2017-01-01
To avoid the inlet unstart at high equivalence ratio and increase the performance of scramjet with ram-mode, a flow control method of boundary-layer ejection is implemented based on the potential thermodynamic process in a turbo-pump supply system of fuel vapor within a cooling channel. The effect of ejection on overall scramjet performance is studied by taking the integration of measures including numerical simulation and stream thrust analysis. Results indicate that the critical backpressure is significantly increased as the ejection total pressure increased, thereby increasing the compression capacity and efficiency, and decreasing the irreversible losses of shock wave and viscous dissipation. For the ejection total pressure of P_t_,_e_j_e = 2.40–4.00 × 10"6 Pa, the critical backpressure ratio is quantitatively increased by 1.18–11.8% along with the utilization of ejection mass flow rate of about 88.0–100% overall mass flow rate of methane fuel gas, and simultaneously the total pressure ratio, kinetic efficiency is also increased by 7.32–13.1%, and 1.63–2.96%, respectively, while the dimensionless entropy increase is decreased by 14.5–26.8%. On this basis, the specific thrust, specific impulse, and total efficiency is increased by 2.84–4.69%, 2.80–4.68%, and 2.87–4.70%, respectively, which re-emphasizes that the boundary-layer ejection is an available fluid control method. - Highlights: • Pressure ratio affects cycle efficiency based on Brayton cycle analysis. • Ejection control concept is defined based on potential thermodynamic process. • Ejection increases compression capacity, efficiency and engine overall performance.
Thermodynamics of hairy black holes in Lovelock gravity
Energy Technology Data Exchange (ETDEWEB)
Hennigar, Robie A. [Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario, Canada, N2L 3G1 (Canada); Tjoa, Erickson [Division of Physics and Applied Physics, School of Physical and Mathematical Sciences,Nanyang Technological University, Singapore, 637371 (Singapore); Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario, Canada, N2L 3G1 (Canada); Mann, Robert B. [Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario, Canada, N2L 3G1 (Canada)
2017-02-14
We perform a thorough study of the thermodynamic properties of a class of Lovelock black holes with conformal scalar hair arising from coupling of a real scalar field to the dimensionally extended Euler densities. We study the linearized equations of motion of the theory and describe constraints under which the theory is free from ghosts/tachyons. We then consider, within the context of black hole chemistry, the thermodynamics of the hairy black holes in the Gauss-Bonnet and cubic Lovelock theories. We clarify the connection between isolated critical points and thermodynamic singularities, finding a one parameter family of these critical points which occur for well-defined thermodynamic parameters. We also report on a number of novel results, including ‘virtual triple points’ and the first example of a ‘λ-line’ — a line of second order phase transitions — in black hole thermodynamics.
Umirzakov, I. H.
2018-01-01
The author comments on an article by Woodcock (Int J Thermophys 35:1770-1784, 2014), who investigates the idea of a critical line instead of a single critical point using the example of argon. In the introduction, Woodcock states that "The Van der Waals critical point does not comply with the Gibbs phase rule. Its existence is based upon a hypothesis rather than a thermodynamic definition". The present comment is a response to the statement by Woodcock. The comment mathematically demonstrates that a critical point is not only based on a hypothesis that is used to define values of two parameters of the Van der Waals equation of state. Instead, the author argues that a critical point is a direct consequence of the thermodynamic phase equilibrium conditions resulting in a single critical point. It is shown that the thermodynamic conditions result in the first and second partial derivatives of pressure with respect to volume at constant temperature at a critical point equal to zero which are usual conditions of an existence of a critical point.
Nanofluidics thermodynamic and transport properties
Michaelides, Efstathios E (Stathis)
2014-01-01
This volume offers a comprehensive examination of the subject of heat and mass transfer with nanofluids as well as a critical review of the past and recent research projects in this area. Emphasis is placed on the fundamentals of the transport processes using particle-fluid suspensions, such as nanofluids. The nanofluid research is examined and presented in a holistic way using a great deal of our experience with the subjects of continuum mechanics, statistical thermodynamics, and non-equilibrium thermodynamics of transport processes. Using a thorough database, the experimental, analytical, and numerical advances of recent research in nanofluids are critically examined and connected to past research with medium and fine particles as well as to functional engineering systems. Promising applications and technological issues of heat/mass transfer system design with nanofluids are also discussed. This book also: Provides a deep scientific analysis of nanofluids using classical thermodynamics and statistical therm...
Efficiency of an air-cooled thermodynamic cycle
International Nuclear Information System (INIS)
Bezborodov, Yu.A.; Bubnov, V.P.; Nesterenko, V.B.
1979-01-01
The application of air, nitrogen, helium and the chemically reacting N 2 O 4 reversible 2NO 2 reversible 2NO + O 2 system as working agents and coolants for a low capacity nuclear power plant is investigated. The above system due to its physico-chemical and thermo-physical properties allows both a gaseous cycle and a cycle with condensation. The analysis has shown that a thermodynamic air-cooled cycle with the dissociating nitrogen tetroxide in the temperature range from 500 to 600 deg C has an advantage over cycles with air and nitrogen. To identify the chemical reaction kinetics in the thermodynamic processes, thermodynamic calculations of the gas-liquid cycle with N 2 O 4 both with simple and intermediate heat regeneration at different pressures over hot side were performed. At gas pressures lower than 12 - 15 atm, the cycle with a simple regeneration is more effective, and at pressure increase, the cycle with an intermediate regeneration is preferable
Thermodynamics of the multicomponent vapor-liquid equilibrium under capillary pressure difference
DEFF Research Database (Denmark)
Shapiro, Alexander; Stenby, Erling Halfdan
2001-01-01
We discuss the two-phase multicomponent equilibrium, provided that the phase pressures are different due to the action of capillary forces. We prove the two general properties of such an equilibrium, which have previously been known for a single-component case, however, to the best of our knowledge......, not for the multicomponent mixtures. The importance is emphasized on the space of the intensive variables P, T and mu (i), where the laws of capillary equilibrium have a simple geometrical interpretation. We formulate thermodynamic problems specific to such an equilibrium, and outline changes to be introduced to common...... algorithms of flash calculations in order to solve these problems. Sample calculations show large variation of the capillary properties of the mixture in the very neighborhood of the phase envelope and the restrictive role of the spinodal surface as a boundary for possible equilibrium states with different...
Improved experimental determination of critical-point data for tungsten
International Nuclear Information System (INIS)
Fucke, W.; Seydel, U.
1980-01-01
It is shown that under certain conditions in resistive pulse-heating experiments, refractory liquid metals can be heated up to the limit of thermodynamic stability (spinodal) of the superheated liquid. Here, an explosion-like decomposition takes place which is directly monitored by measurements of expansion, surface radiation, and electric resistivity, thus allowing the determination of the temperature-pressure dependence of the spinodal transition. A comparison of the spinodal equation obtained this way with theoretical models yields the critical temperature Tsub(c), pressure psub(c), and volume vsub(c). A completely experimentally-determined set of the critical parameters for tungsten is presented: Tsub(c) = (13400 +- 1400) K, psub(c) = (3370 +- 850) bar, vsub(c) = (43 +- 4) cm 3 mol -1 . (author)
Transformations between Extensive and Intensive Versions of Thermodynamic Relationships
Eberhart, James G.
2010-01-01
Most thermodynamic properties are either extensive (e.g., volume, energy, entropy, amount, etc.) or intensive (e.g., temperature, pressure, chemical potential, mole fraction, etc.). By the same token most of the mathematical relationships in thermodynamics can be written in extensive or intensive form. The basic laws of thermodynamics are usually…
Thermodynamic properties of cesium in the gaseous phase
International Nuclear Information System (INIS)
Vargaftik, N.B.; Voljak, L.D.; Stepanov, V.G.
1985-01-01
Tables of the thermodynamic properties of caesium in the gaseous phase are presented for a wide range of temperature and pressure. The thermodynamic properties include: enthalpy, entropy, specific heat, specific volume, sound velocity and compressibility factor. The values have been calculated from pressure-volume-temperature measurements by various authors. Experimental apparatus to determine these measurements is described, together with an outline of the method employed to process the results, and the error estimates. (U.K.)
International Nuclear Information System (INIS)
Vidal, O.; Dubacq, B.
2010-01-01
Document available in extended abstract form only. Full text of publication follows: The evaluation of the performance of clay-rich barrier considered for the disposal of radioactive waste and a reliable prediction of the impact of repository-induced disturbances upon the confinement properties of clay-rich geological formations requires reliable thermodynamic models for clay minerals. Such models have to take into account the variation of the hydration state of smectite as a function of temperature, pressure and water activity. We propose the first macroscopic thermodynamic model that account for the stepwise dehydration with increasing temperature or decreasing H 2 O activity of K, Na, Ca and Mg-smectite. The model relies on the relative stability of the different solid-solutions that describe the hydration of di- or tri-octahedral-smectites containing 0, 1, 2 or 3 interlayer water layers. The inclusion of anhydrous mica end-members makes it possible to cover, with the same solid-solution model, the entire range of composition from low-charge to high-charge smectite, through illite to mica. Non-ideal Margules parameters were used to describe the non-ideality of the solid solutions between the hydrated and dehydrated smectite end-members. Standard state properties of all smectite end-members as well as Ca- and Mg-muscovite and -phlogopite were initially estimated by oxide summation. These values were then refined and the other non-ideal interactions were estimated on the basis of different experimental data. The stepwise dehydration of smectite, and its stability and compatibility relations were calculated by Gibbs free energy minimizing. Our results account for the progressive evolution of smectite to inter-layered illite/smectite and then to mica, as observed in nature and experiments, and our model provides an explanation for the thermodynamic stability of smectite and illite/ smectite compared to mica + kaolinite or pyrophyllite assemblages. The results
Radical kinetics in sub- and supercritical carbon dioxide: thermodynamic rate tuning.
Ghandi, Khashayar; McFadden, Ryan M L; Cormier, Philip J; Satija, Paras; Smith, Marisa
2012-06-28
We report rate constants for muonium addition to 1,1-difluoroethylene (vinylidene fluoride) in CO2 at 290-530 K, 40-360 bar, and 0.05-0.90 g cm(-3). Rate constants are mapped against their thermodynamic conditions, demonstrating the kinetic tuning ability of the solvent. The reaction exhibits critical slowing near conditions of maximum solvent isothermal compressibility, where activation volumes of unprecedentedly large magnitudes on the order of ±10(6) cm(3) mol(-1) are observed. Such values are suggestive of pressure being a significant parameter for tuning fluorolkene reactivity.
Thermodynamic properties of cryogenic fluids
Leachman, Jacob; Lemmon, Eric; Penoncello, Steven
2017-01-01
This update to a classic reference text provides practising engineers and scientists with accurate thermophysical property data for cryogenic fluids. The equations for fifteen important cryogenic fluids are presented in a basic format, accompanied by pressure-enthalpy and temperature-entropy charts and tables of thermodynamic properties. It begins with a chapter introducing the thermodynamic relations and functional forms for equations of state, and goes on to describe the requirements for thermodynamic property formulations, needed for the complete definition of the thermodynamic properties of a fluid. The core of the book comprises extensive data tables and charts for the most commonly-encountered cryogenic fluids. This new edition sees significant updates to the data presented for air, argon, carbon monoxide, deuterium, ethane, helium, hydrogen, krypton, nitrogen and xenon. The book supports and complements NIST’s REFPROP - an interactive database and tool for the calculation of thermodynamic propertie...
Detonation Jet Engine. Part 1--Thermodynamic Cycle
Bulat, Pavel V.; Volkov, Konstantin N.
2016-01-01
We present the most relevant works on jet engine design that utilize thermodynamic cycle of detonative combustion. The efficiency advantages of thermodynamic detonative combustion cycle over Humphrey combustion cycle at constant volume and Brayton combustion cycle at constant pressure were demonstrated. An ideal Ficket-Jacobs detonation cycle, and…
International Nuclear Information System (INIS)
Dumaz, P.; Antoni, O; Arnoux, P.; Bergeron, A; Renault, C.; Rimpault, G.
2005-01-01
Water is used as a calori-porter and moderator in the most major nuclear centers which are actually in function. In the pressurized water reactor (PWR) and boiling water reactor (BWR), water is maintained under critical point of water (21 bar, 374 Centigrade) which limits the efficiency of thermodynamic cycle of energy conversion (yield gain of about 33%) Crossing the critical point, one can then use s upercritical water , the obtained pressure and temperature allow a significant yield gains. In addition, the supercritical water offers important properties. Particularly there is no more possible coexistence between vapor and liquid. Therefore, we don't have more boiling problem, one of the phenomena which limits the specific power of PWR and BWR. Since 1950s, the reactor of supercritical water was the subject of studies more or less detailed but neglected. From the early 1990s, this type of conception benefits of some additional interests. Therefore, in the international term G eneration IV , the supercritical water reactors had been considered as one of the big options for study as Generation IV reactors. In the CEA, an active city has engaged from 1930 with the participation to a European program: The HPWR (High Performance Light Water Reactor). In this contest, the R and D studies are focused on the fields of neutrons, thermodynamic and materials. The CEA intends to pursue a limited effort of R and D in this field, in the framework of international cooperation, preferring the study of versions of rapid spectrum. (author)
Theoretical physics 5 thermodynamics
Nolting, Wolfgang
2017-01-01
This concise textbook offers a clear and comprehensive introduction to thermodynamics, one of the core components of undergraduate physics courses. It follows on naturally from the previous volumes in this series, defining macroscopic variables, such as internal energy, entropy and pressure,together with thermodynamic principles. The first part of the book introduces the laws of thermodynamics and thermodynamic potentials. More complex themes are covered in the second part of the book, which describes phases and phase transitions in depth. Ideally suited to undergraduate students with some grounding in classical mechanics, the book is enhanced throughout with learning features such as boxed inserts and chapter summaries, with key mathematical derivations highlighted to aid understanding. The text is supported by numerous worked examples and end of chapter problem sets. About the Theoretical Physics series Translated from the renowned and highly successful German editions, the eight volumes of this series cove...
Energy Technology Data Exchange (ETDEWEB)
Sun, Wenming; Liu, Jing; Wang, Hong [China Building Materials Academy, Beijing (China); Zhang, Zhenwei [Linyi Academy of Technology Cooperation and Application, Linyi (China); Zhang, Liang [NeoTrident Technology Ltd., Shanghai (China); Bu, Yuxiang [Shandong University, Jinan (China)
2017-02-15
For guidance for developing Fe/Co-Sn-based anode materials for lithium-ion batteries, the mechanical, thermodynamic and electronic properties of FeSn{sub 5} and CoSn{sub 5} intermetallic phases under pressures ranging from 0 to 30 GPa have been investigated systematically using first-principles total-energy calculations within the framework of the generalized gradient approximation. The pressure was found to have significant effects on the mechanical, thermodynamic and electronic properties of these compounds. In the selected pressure range, CoSn{sub 5} has a more negative formation enthalpy than FeSn{sub 5}. Based on the calculated elastic constants, the bulk modulus, shear modulus, and Young's modulus were determined via the Viogt-Reuss-Hill averaging scheme. The variations of specific heats at constant volume for FeSn{sub 5} and CoSn{sub 5} in a wide pressure (0 - 30 GPa) and temperature (0 - 1000 K) range are also predicted from phonon density of states calculation. The calculated results suggested that both FeSn{sub 5} and CoSn{sub 5} are mechanically stable at pressure from 0 to 30 GPa. FeSn{sub 5} is dynamically stable at pressure up to, 30 GPa, at least, however, CoSn{sub 5} is dynamically stable no higher than 15 GPa.
Holographic free energy and thermodynamic geometry
Ghorai, Debabrata; Gangopadhyay, Sunandan
2016-12-01
We obtain the free energy and thermodynamic geometry of holographic superconductors in 2+1 dimensions. The gravitational theory in the bulk dual to this 2+1-dimensional strongly coupled theory lives in the 3+1 dimensions and is that of a charged AdS black hole together with a massive charged scalar field. The matching method is applied to obtain the nature of the fields near the horizon using which the holographic free energy is computed through the gauge/gravity duality. The critical temperature is obtained for a set of values of the matching point of the near horizon and the boundary behaviour of the fields in the probe limit approximation which neglects the back reaction of the matter fields on the background spacetime geometry. The thermodynamic geometry is then computed from the free energy of the boundary theory. From the divergence of the thermodynamic scalar curvature, the critical temperature is obtained once again. We then compare this result for the critical temperature with that obtained from the matching method.
Holographic free energy and thermodynamic geometry
International Nuclear Information System (INIS)
Ghorai, Debabrata; Gangopadhyay, Sunandan
2016-01-01
We obtain the free energy and thermodynamic geometry of holographic superconductors in 2 + 1 dimensions. The gravitational theory in the bulk dual to this 2 + 1-dimensional strongly coupled theory lives in the 3 + 1 dimensions and is that of a charged AdS black hole together with a massive charged scalar field. The matching method is applied to obtain the nature of the fields near the horizon using which the holographic free energy is computed through the gauge/gravity duality. The critical temperature is obtained for a set of values of the matching point of the near horizon and the boundary behaviour of the fields in the probe limit approximation which neglects the back reaction of the matter fields on the background spacetime geometry. The thermodynamic geometry is then computed from the free energy of the boundary theory. From the divergence of the thermodynamic scalar curvature, the critical temperature is obtained once again. We then compare this result for the critical temperature with that obtained from the matching method. (orig.)
Holographic free energy and thermodynamic geometry
Energy Technology Data Exchange (ETDEWEB)
Ghorai, Debabrata [S.N. Bose National Centre for Basic Sciences, Kolkata (India); Gangopadhyay, Sunandan [Indian Institute of Science Education and Research, Kolkata, Nadia (India); West Bengal State University, Department of Physics, Barasat (India); Inter University Centre for Astronomy and Astrophysics, Pune (India)
2016-12-15
We obtain the free energy and thermodynamic geometry of holographic superconductors in 2 + 1 dimensions. The gravitational theory in the bulk dual to this 2 + 1-dimensional strongly coupled theory lives in the 3 + 1 dimensions and is that of a charged AdS black hole together with a massive charged scalar field. The matching method is applied to obtain the nature of the fields near the horizon using which the holographic free energy is computed through the gauge/gravity duality. The critical temperature is obtained for a set of values of the matching point of the near horizon and the boundary behaviour of the fields in the probe limit approximation which neglects the back reaction of the matter fields on the background spacetime geometry. The thermodynamic geometry is then computed from the free energy of the boundary theory. From the divergence of the thermodynamic scalar curvature, the critical temperature is obtained once again. We then compare this result for the critical temperature with that obtained from the matching method. (orig.)
Knudsen, P.; Ganni, V.
2017-12-01
Concurrent pressure drop and cooling of a super-critical or sub-cooled liquid stream can have the same effect as adiabatic expansion even though there is no work extraction. A practical implementation is as straight forward as counter-flow heat exchange with a colder fluid. The concurrent pressure drop need not be continuous with respect to the heat exchange, but may occur in a step-wise manner, in between heat exchange. Two aspects of this effect of pressure drop with heat transfer are examined; a thermodynamic and a practical process equivalent isentropic expansion efficiency. This real fluid phenomenon is useful to understand in applications where work extraction is either not practical or has not been developed. A super-critical helium supply, often around 3 bar and 4.5 K, being ultimately used as a superfluid (usually around 1.8 to 2.1 K) to cool a Niobium superconducting radio frequency cavity or a superconducting magnet is one such particular application. This paper examines the thermodynamic nature of this phenomenon.
International Nuclear Information System (INIS)
Kim, Junghwan; Jung, In-Ho
2015-01-01
Highlights: • The (Si-RE) (RE = Gd, Tb, Dy, Ho, Er, Tm, Lu and Y) systems have been reviewed. • The thermodynamic optimization of the (Si-RE) systems have been performed. • Systematic changes and similarities in the (Si-RE) systems were found. • The systematic approach resolved inconsistencies in the experimental data. • The systematic approach was used to assess the unexplored phase diagrams. - Abstract: A critical evaluation and optimisation of all available phase diagrams and thermodynamic data of the (Si-RE) (RE = Gd, Tb, Dy, Ho, Er, Tm, Lu and Y) systems was conducted to obtain reliable thermodynamic functions of all the phases in the system. In the thermodynamic modelling, a systematic analysis involving the similarity and periodicity observed in the lanthanide series was applied to resolve inconsistencies in the experimental data and to estimate the unknown thermodynamic properties and phase equilibria data. In particular, the phase diagrams and thermodynamic properties of (Si-Tm) and (Si-Lu) systems which are rarely investigated can be predicted from this approach. Systematic trends in thermodynamic properties of solid and liquid phases and phase diagram of the entire (Si-RE) systems were summarized
Dukes, Susan F; Maupin, Genny M; Thomas, Marilyn E; Mortimer, Darcy L
2018-04-01
The US Air Force transports critically ill patients from all over the world, with transport times commonly ranging from 6 to 11 hours. Few outcome measures have been tracked for these patients. Traditional methods to prevent pressure injuries in civilian hospitals are often not feasible in the military transport environment. The incidence rate and risk factors are described of en route-related pressure injuries for patients overseen by the Critical Care Air Transport Team. This retrospective, case-control, medical records review investigated risk factors for pressure injury in patients who developed a pressure injury after their transport flight compared with those with no documented pressure injuries. The pressure injury rate was 4.9%. Between 2008 and 2012, 141 patients in whom pressure injuries developed and who had received care by the team were matched with 141 patients cared for by the team but did not have pressure injury. According to regression analysis, body mass index and 2 or more Critical Care Air Transport Team transports per patient were associated with pressure injury development. Although the pressure injury rate of 4.9% in this cohort of patients is consistent with that reported by civilian critical care units, the rate must be interpreted with caution, because civilian study data frequently represent the entire intensive care unit length of stay. Targeted interventions for patients with increased body mass index and 2 or more critical care air transports per patient may help decrease the development of pressure injury in these patients. ©2018 American Association of Critical-Care Nurses.
International Nuclear Information System (INIS)
Berg, M.S. van den.
1995-01-01
Thermodynamic parameters and transport coefficients have been calculated for a multicomponent reacting U-C-F gas mixture in the steady flow gaseous core fission reactor. Element abundances are consistent with thermodynamic equilibrium between the gas mixture and a cooled solid graphite wall at 2500 K. Results are presented for various pressures, a fluorine potential of 5.6 and temperatures between 2500 and 7000 K. As a result of dissociation processes of uranium and carbon fluoride compounds, ''effective'' values of thermodynamic parameters and transport coefficients show anomalous behaviour with respect to so-called ''frozen'' values. The chemical reaction energy of the U-C-F gas mixture has been calculated as the driving-force behind the process of fuel redistribution to attain criticality conditions inside a functioning reactor. (author)
A noninvasive estimation of cerebral perfusion pressure using critical closing pressure.
Varsos, Georgios V; Kolias, Angelos G; Smielewski, Peter; Brady, Ken M; Varsos, Vassilis G; Hutchinson, Peter J; Pickard, John D; Czosnyka, Marek
2015-09-01
Cerebral blood flow is associated with cerebral perfusion pressure (CPP), which is clinically monitored through arterial blood pressure (ABP) and invasive measurements of intracranial pressure (ICP). Based on critical closing pressure (CrCP), the authors introduce a novel method for a noninvasive estimator of CPP (eCPP). Data from 280 head-injured patients with ABP, ICP, and transcranial Doppler ultrasonography measurements were retrospectively examined. CrCP was calculated with a noninvasive version of the cerebrovascular impedance method. The eCPP was refined with a predictive regression model of CrCP-based estimation of ICP from known ICP using data from 232 patients, and validated with data from the remaining 48 patients. Cohort analysis showed eCPP to be correlated with measured CPP (R = 0.851, p area under the curve of 0.913 (95% CI 0.883-0.944). When each recording session of a patient was assessed individually, eCPP could predict CPP with a 95% CI of the SD for estimating CPP between multiple recording sessions of 1.89-5.01 mm Hg. Overall, CrCP-based eCPP was strongly correlated with invasive CPP, with sensitivity and specificity for detection of low CPP that show promise for clinical use.
Nonperturbative quark-gluon thermodynamics at finite density
Andreichikov, M. A.; Lukashov, M. S.; Simonov, Yu. A.
2018-03-01
Thermodynamics of the quark-gluon plasma at finite density is studied in the framework of the Field Correlator Method, where thermodynamical effects of Polyakov loops and color magnetic confinement are taken into account. Having found good agreement with numerical lattice data for zero density, we calculate pressure P(T,μ), for 0 confinement.
International Nuclear Information System (INIS)
Chirico, Robert D.; Kazakov, Andrei F.
2015-01-01
Highlights: • Heat capacities were measured for the temperature range (5 to 520) K. • The enthalpy of combustion was measured and the enthalpy of formation was derived. • Thermodynamic-consistency analysis resolved inconsistencies in literature enthalpies of sublimation. • An inconsistency in literature enthalpies of combustion was resolved. • Application of computational chemistry in consistency analysis was demonstrated successfully. - Abstract: Heat capacities and phase-transition properties for xanthone (IUPAC name 9H-xanthen-9-one and Chemical Abstracts registry number [90-47-1]) are reported for the temperature range 5 < T/K < 524. Statistical calculations were performed and thermodynamic properties for the ideal gas were derived based on molecular geometry optimization and vibrational frequencies calculated at the B3LYP/6-31+G(d,p) level of theory. These results are combined with sublimation pressures from the literature to allow critical evaluation of inconsistent enthalpies of sublimation for xanthone, also reported in the literature. Literature values for the enthalpy of combustion of xanthone are re-assessed, a revision is recommended for one result, and a new value for the enthalpy of formation of the ideal gas is derived. Comparisons with thermophysical properties reported in the literature are made for all other reported and derived properties, where possible
Thermodynamic analysis and numerical modeling of supercritical injection
Banuti, Daniel
2015-01-01
Although liquid propellant rocket engines are operational and have been studied for decades, cryogenic injection at supercritical pressures is still considered essentially not understood. This thesis intends to approach this problem in three steps: by developing a numerical model for real gas thermodynamics, by extending the present thermodynamic view of supercritical injection, and finally by applying these methods to the analysis of injection. A new numerical real gas thermodynamics mode...
Critical behaviors of gravity under quantum perturbations
Directory of Open Access Journals (Sweden)
ZHANG Hongsheng
2014-02-01
Full Text Available Phase transition and critical phenomenon is a very interesting topic in thermodynamics and statistical mechanics. Gravity is believed to have deep and inherent relation to thermodynamics. Near the critical point,the perturbation becomes significant. Thus for ordinary matter (governed by interactions besides gravity the critical behavior will become very different if we ignore the perturbations around the critical point,such as mean field theory. We find that the critical exponents for RN-AdS spacetime keep the same values even when we consider the full quantum perturbations. This indicates a key difference between gravity and ordinary thermodynamic system.
Smirnov, N. A.
2018-03-01
The paper investigates the role of spin-orbit interaction in the prediction of structural stability, lattice dynamics, elasticity, thermodynamic and transport properties (electrical resistivity and thermal conductivity) of lead under pressure with the FP-LMTO (full-potential linear-muffin-tin orbital) method for the first-principles band structure calculations. Our calculations were carried out for three polymorphous lead modifications (fcc, hcp, and bcc) in generalized gradient approximation with the exchange-correlation functional PBEsol. They suggest that compared to the scalar-relativistic calculation, the account for the SO effects insignificantly influences the compressibility of Pb. At the same time, in the calculation of phonon spectra and transport properties, the role of SO interaction is important, at least, for P ≲150 GPa. At higher pressures, the contribution from SO interaction reduces but not vanishes. As for the relative structural stability, our studies show that SO effects influence weakly the pressure of the fcc →hcp transition and much higher the pressure of the hcp →bcc transition.
Hasan, Nusair; Farouk, Bakhtier
2015-10-01
Flow and transport induced by resonant acoustic waves in a near-critical fluid filled cylindrical enclosure is investigated both experimentally and numerically. Supercritical carbon dioxide (near the critical or the pseudo-critical states) in a confined resonator is subjected to acoustic field created by an electro-mechanical acoustic transducer and the induced pressure waves are measured by a fast response pressure field microphone. The frequency of the acoustic transducer is chosen such that the lowest acoustic mode propagates along the enclosure. For numerical simulations, a real-fluid computational fluid dynamics model representing the thermo-physical and transport properties of the supercritical fluid is considered. The simulated acoustic field in the resonator is compared with measurements. The formation of acoustic streaming structures in the highly compressible medium is revealed by time-averaging the numerical solutions over a given period. Due to diverging thermo-physical properties of supercritical fluid near the critical point, large scale oscillations are generated even for small sound field intensity. The strength of the acoustic wave field is found to be in direct relation with the thermodynamic state of the fluid. The effects of near-critical property variations and the operating pressure on the formation process of the streaming structures are also investigated. Irregular streaming patterns with significantly higher streaming velocities are observed for near-pseudo-critical states at operating pressures close to the critical pressure. However, these structures quickly re-orient to the typical Rayleigh streaming patterns with the increase operating pressure.
Optimization of powered Stirling heat engine with finite speed thermodynamics
International Nuclear Information System (INIS)
Ahmadi, Mohammad H.; Ahmadi, Mohammad Ali; Pourfayaz, Fathollah; Bidi, Mokhtar; Hosseinzade, Hadi; Feidt, Michel
2016-01-01
Highlights: • Based on finite speed method and direct method, the optimal performance is investigated. • The effects of major parameters on the optimal performance are investigated. • The accuracy of the results was compared with previous works. - Abstract: Popular thermodynamic analyses including finite time thermodynamic analysis was lately developed based upon external irreversibilities while internal irreversibilities such as friction, pressure drop and entropy generation were not considered. The aforementioned disadvantage reduces the reliability of the finite time thermodynamic analysis in the design of an accurate Stirling engine model. Consequently, the finite time thermodynamic analysis could not sufficiently satisfy researchers for implementing in design and optimization issues. In this study, finite speed thermodynamic analysis was employed instead of finite time thermodynamic analysis for studying Stirling heat engine. The finite speed thermodynamic analysis approach is based on the first law of thermodynamics for a closed system with finite speed and the direct method. The effects of heat source temperature, regenerating effectiveness, volumetric ratio, piston stroke as well as rotational speed are included in the analysis. Moreover, maximum output power in optimal rotational speed was calculated while pressure losses in the Stirling engine were systematically considered. The result reveals the accuracy and the reliability of the finite speed thermodynamic method in thermodynamic analysis of Stirling heat engine. The outcomes can help researchers in the design of an appropriate and efficient Stirling engine.
Black hole chemistry: thermodynamics with Lambda
International Nuclear Information System (INIS)
Kubizňák, David; Mann, Robert B; Teo, Mae
2017-01-01
We review recent developments on the thermodynamics of black holes in extended phase space, where the cosmological constant is interpreted as thermodynamic pressure and treated as a thermodynamic variable in its own right. In this approach, the mass of the black hole is no longer regarded as internal energy, rather it is identified with the chemical enthalpy. This leads to an extended dictionary for black hole thermodynamic quantities; in particular a notion of thermodynamic volume emerges for a given black hole spacetime. This volume is conjectured to satisfy the reverse isoperimetric inequality—an inequality imposing a bound on the amount of entropy black hole can carry for a fixed thermodynamic volume. New thermodynamic phase transitions naturally emerge from these identifications. Namely, we show that black holes can be understood from the viewpoint of chemistry, in terms of concepts such as Van der Waals fluids, reentrant phase transitions, and triple points. We also review the recent attempts at extending the AdS/CFT dictionary in this setting, discuss the connections with horizon thermodynamics, applications to Lifshitz spacetimes, and outline possible future directions in this field. (topical review)
Toward thermodynamic consistency of quasiparticle picture
International Nuclear Information System (INIS)
Biro, T.S.; Toneev, V.D.; Shanenko, A.A.
2003-01-01
The purpose of the present article is to call attention to some realistic quasiparticle-based description of quark/gluon matter and its consistent implementation in thermodynamics. A simple and transparent representation of the thermodynamic consistency conditions is given. This representation allows one to review critically and systemize available phenomenological approaches to the deconfinement problem with respect to their thermodynamic consistency. Particular attention is paid to the development of a method for treating the string screening in the dense matter of unbound color charges. The proposed method yields an integrable effective pair potential that can be incorporated into the mean-field picture. The results of its application are in reasonable agreement with lattice data on the QCD thermodynamics
Black hole thermodynamics with conical defects
Energy Technology Data Exchange (ETDEWEB)
Appels, Michael [Centre for Particle Theory, Durham University,South Road, Durham, DH1 3LE (United Kingdom); Gregory, Ruth [Centre for Particle Theory, Durham University,South Road, Durham, DH1 3LE (United Kingdom); Perimeter Institute,31 Caroline Street North, Waterloo, ON, N2L 2Y5 (Canada); Kubiznák, David [Perimeter Institute,31 Caroline Street North, Waterloo, ON, N2L 2Y5 (Canada)
2017-05-22
Recently we have shown https://www.doi.org/10.1103/PhysRevLett.117.131303 how to formulate a thermodynamic first law for a single (charged) accelerated black hole in AdS space by fixing the conical deficit angles present in the spacetime. Here we show how to generalise this result, formulating thermodynamics for black holes with varying conical deficits. We derive a new potential for the varying tension defects: the thermodynamic length, both for accelerating and static black holes. We discuss possible physical processes in which the tension of a string ending on a black hole might vary, and also map out the thermodynamic phase space of accelerating black holes and explore their critical phenomena.
Thermodynamic optimization of the Cu-Nd system
International Nuclear Information System (INIS)
Wang Peisheng; Zhou Liangcai; Du Yong; Xu Honghui; Liu Shuhong; Chen Li; Ouyang Yifang
2011-01-01
Research highlights: → The enthalpies of formation of the compounds Cu 6 Nd, Cu 5 Nd, Cu 2 Nd and αCuNd were calculated using DFT. → The thermodynamic constraints to eliminate the artificial phase relations were imposed during the thermodynamic optimization procedure. → The Cu-Nd system was optimized under the thermodynamic constraints. - Abstract: The thermodynamic constraints to eliminate artificial phase relations were introduced with the Cu-Nd system as an example. The enthalpies of formation of the compounds Cu 6 Nd, Cu 5 Nd, Cu 2 Nd and αCuNd are calculated using density functional theory. Taking into account all the experimental data and the first-principles calculated enthalpies of formation of these compounds, the thermodynamic optimization of the Cu-Nd system was performed under the proposed thermodynamic constraints. It is demonstrated that the thermodynamic constraints are critical to obtain a set of thermodynamic parameters for the Cu-Nd system, which can avoid the appearance of all the artificial phase relations.
A Retrospective study of Pressure ulcers in critically ill patients in a ...
African Journals Online (AJOL)
A Retrospective study of Pressure ulcers in critically ill patients in a ... reduced tissue perfusion, neurologic deficits, faecal or urinary incontinence. This study determined the prevalence and risk factors for the development of pressure ulcer in ...
Thermodynamic properties of uranium--mercury system
International Nuclear Information System (INIS)
Lee, T.S.
1979-01-01
The EMF values in the fused salt cells of the type U(α)/KCl--LiCl--BaCl 2 eutectic, UCl 3 /U--Hg alloy, for the different two-phase alloys in the uranium--mercury system have been measured and the thermodynamic properties of this system have been calculated. These calculated values are in good agreement with values based on mercury vapor pressure measurements made by previous investigators. The inconsistency of the thermodynamic properties with the phase diagram determined by Frost are also confirmed. A tentative phase diagram based on the thermodynamic properties measured in this work was constructed
Thermodynamic estimation: Ionic materials
International Nuclear Information System (INIS)
Glasser, Leslie
2013-01-01
Thermodynamics establishes equilibrium relations among thermodynamic parameters (“properties”) and delineates the effects of variation of the thermodynamic functions (typically temperature and pressure) on those parameters. However, classical thermodynamics does not provide values for the necessary thermodynamic properties, which must be established by extra-thermodynamic means such as experiment, theoretical calculation, or empirical estimation. While many values may be found in the numerous collected tables in the literature, these are necessarily incomplete because either the experimental measurements have not been made or the materials may be hypothetical. The current paper presents a number of simple and relible estimation methods for thermodynamic properties, principally for ionic materials. The results may also be used as a check for obvious errors in published values. The estimation methods described are typically based on addition of properties of individual ions, or sums of properties of neutral ion groups (such as “double” salts, in the Simple Salt Approximation), or based upon correlations such as with formula unit volumes (Volume-Based Thermodynamics). - Graphical abstract: Thermodynamic properties of ionic materials may be readily estimated by summation of the properties of individual ions, by summation of the properties of ‘double salts’, and by correlation with formula volume. Such estimates may fill gaps in the literature, and may also be used as checks of published values. This simplicity arises from exploitation of the fact that repulsive energy terms are of short range and very similar across materials, while coulombic interactions provide a very large component of the attractive energy in ionic systems. Display Omitted - Highlights: • Estimation methods for thermodynamic properties of ionic materials are introduced. • Methods are based on summation of single ions, multiple salts, and correlations. • Heat capacity, entropy
International Nuclear Information System (INIS)
Hamm, L.L.; Van Brunt, V.
1982-08-01
The Christiansen and Fredenslund programs for calculating vapor-liquid equilibria have been modified by replacing the Soave-Redlich-Kwong equation of state with the newly developed Peng-Robinson equation of state. This modification was shown to be a decided improvement for high pressure systems, especially in the critical and upper retrograde regions. Thermodynamic consistency tests were developed and used to evaluate and compare calculated values from both the modified and unmodified programs with reported experimental data for several vapor-liquid systems
Critical point analysis of phase envelope diagram
International Nuclear Information System (INIS)
Soetikno, Darmadi; Siagian, Ucok W. R.; Kusdiantara, Rudy; Puspita, Dila; Sidarto, Kuntjoro A.; Soewono, Edy; Gunawan, Agus Y.
2014-01-01
Phase diagram or phase envelope is a relation between temperature and pressure that shows the condition of equilibria between the different phases of chemical compounds, mixture of compounds, and solutions. Phase diagram is an important issue in chemical thermodynamics and hydrocarbon reservoir. It is very useful for process simulation, hydrocarbon reactor design, and petroleum engineering studies. It is constructed from the bubble line, dew line, and critical point. Bubble line and dew line are composed of bubble points and dew points, respectively. Bubble point is the first point at which the gas is formed when a liquid is heated. Meanwhile, dew point is the first point where the liquid is formed when the gas is cooled. Critical point is the point where all of the properties of gases and liquids are equal, such as temperature, pressure, amount of substance, and others. Critical point is very useful in fuel processing and dissolution of certain chemicals. Here in this paper, we will show the critical point analytically. Then, it will be compared with numerical calculations of Peng-Robinson equation by using Newton-Raphson method. As case studies, several hydrocarbon mixtures are simulated using by Matlab
Critical point analysis of phase envelope diagram
Energy Technology Data Exchange (ETDEWEB)
Soetikno, Darmadi; Siagian, Ucok W. R. [Department of Petroleum Engineering, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung 40132 (Indonesia); Kusdiantara, Rudy, E-mail: rkusdiantara@s.itb.ac.id; Puspita, Dila, E-mail: rkusdiantara@s.itb.ac.id; Sidarto, Kuntjoro A., E-mail: rkusdiantara@s.itb.ac.id; Soewono, Edy; Gunawan, Agus Y. [Department of Mathematics, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung 40132 (Indonesia)
2014-03-24
Phase diagram or phase envelope is a relation between temperature and pressure that shows the condition of equilibria between the different phases of chemical compounds, mixture of compounds, and solutions. Phase diagram is an important issue in chemical thermodynamics and hydrocarbon reservoir. It is very useful for process simulation, hydrocarbon reactor design, and petroleum engineering studies. It is constructed from the bubble line, dew line, and critical point. Bubble line and dew line are composed of bubble points and dew points, respectively. Bubble point is the first point at which the gas is formed when a liquid is heated. Meanwhile, dew point is the first point where the liquid is formed when the gas is cooled. Critical point is the point where all of the properties of gases and liquids are equal, such as temperature, pressure, amount of substance, and others. Critical point is very useful in fuel processing and dissolution of certain chemicals. Here in this paper, we will show the critical point analytically. Then, it will be compared with numerical calculations of Peng-Robinson equation by using Newton-Raphson method. As case studies, several hydrocarbon mixtures are simulated using by Matlab.
Extended Irreversible Thermodynamics
Jou, David
2010-01-01
This is the 4th edition of the highly acclaimed monograph on Extended Irreversible Thermodynamics, a theory that goes beyond the classical theory of irreversible processes. In contrast to the classical approach, the basic variables describing the system are complemented by non-equilibrium quantities. The claims made for extended thermodynamics are confirmed by the kinetic theory of gases and statistical mechanics. The book covers a wide spectrum of applications, and also contains a thorough discussion of the foundations and the scope of the current theories on non-equilibrium thermodynamics. For this new edition, the authors critically revised existing material while taking into account the most recent developments in fast moving fields such as heat transport in micro- and nanosystems or fast solidification fronts in materials sciences. Several fundamental chapters have been revisited emphasizing physics and applications over mathematical derivations. Also, fundamental questions on the definition of non-equil...
International Nuclear Information System (INIS)
Richard T. Scalettar; Warren E. Pickett
2005-01-01
This project involves research into the thermodynamic properties of f-electron metals, transition metal oxides, and half-metallic magnets at high pressure. These materials are ones in which the changing importance of electron-electron interactions as the distance between atoms is varied can tune the system through phase transitions from localized to delocalized electrons, from screened to unscreened magnetic moments, and from normal metal to one in which only a single spin specie can conduct. Three main thrusts are being pursued: (1) Mott transitions in transition metal oxides, (2) magnetism in half-metallic compounds, and (3) large volume-collapse transitions in f-band metals
Energy Technology Data Exchange (ETDEWEB)
Scalettar, Richard T.; Pickett, Warren E.
2004-07-01
This project involves research into the thermodynamic properties of f-electron metals, transition metal oxides, and half-metallic magnets at high pressure. These materials are ones in which the changing importance of electron-electron interactions as the distance between atoms is varied can tune the system through phase transitions from localized to delocalized electrons, from screened to unscreened magnetic moments, and from normal metal to one in which only a single spin specie can conduct. Three main thrusts are being pursued: (1) Mott transitions in transition metal oxides, (2) magnetism in half-metallic compounds, and (3) large volume-collapse transitions in f-band metals.
Energy Technology Data Exchange (ETDEWEB)
Richard T. Scalettar; Warren E. Pickett
2005-08-02
This project involves research into the thermodynamic properties of f-electron metals, transition metal oxides, and half-metallic magnets at high pressure. These materials are ones in which the changing importance of electron-electron interactions as the distance between atoms is varied can tune the system through phase transitions from localized to delocalized electrons, from screened to unscreened magnetic moments, and from normal metal to one in which only a single spin specie can conduct. Three main thrusts are being pursued: (i) Mott transitions in transition metal oxides, (ii) magnetism in half-metallic compounds, and (iii) large volume-collapse transitions in f-band metals.
Security of bottle to fill in a high pressure air
Todic, M.; Latinovic, T.; Golubovic-Bugarski, V.; Majstorovic, A.
2018-01-01
Charging the bottle of high pressure air isolation devices is performed by a high-pressure compressor. The charging time is in function of the compressor capacity and the intensity of the nominal pressure of the air in the bottle. However, in accident situations this time is long and therefore high-pressure accumulators are used where the filling time of the bottle of isolation apparatus has been drastically reduced. Due to the short filling time of the bottle through the air flow, there is a thermodynamic load of bottle material that could endanger the safety of users and other participants in the area. It is therefore necessary to determine the critical parameters of the rapid charge and their intensity.
Journaux, B.; Brown, J. M.; Bollengier, O.; Abramson, E.
2017-12-01
As in Earth arctic and Antarctic regions, suspected extraterrestrial deep oceans in icy worlds (i.e. icy moons and water-rich exoplanets) chemistry and thermodynamic state will strongly depend on their equilibrium with H2O ice and present solutes. Na-Mg-Cl-SO4 salt species are currently the main suspected ionic solutes to be present in deep oceans based on remote sensing, magnetic field measurements, cryovolcanism ice grains chemical analysis and chondritic material aqueous alteration chemical models. Unlike on our planet, deep extraterrestrial ocean might also be interacting at depth with high pressure ices (e.g. III, V, VI, VI, X) which have different behavior compared to ice Ih. Unfortunately, the pressures and temperatures inside these hydrospheres differ significantly from the one found in Earth aqueous environments, so most of our current thermodynamic databases do not cover the range of conditions relevant for modeling realistically large icy worlds interiors. Recent experimental results have shown that the presence of solutes, and more particularly salts, in equilibrium with high pressure ices have large effects on the stability, buoyancy and chemistry of all the phases present at these extreme conditions. High pressure in-situ measurements using diamond anvil cell apparatus were operated both at the University of washington and at the European Synchrotron Radiation Facility on aqueous systems phase diagrams with Na-Mg-Cl-SO4 species, salt incorporation in high pressure ices and density inversions between the solid and the fluids. These results suggest a more complex picture of the interior structure, dynamic and chemical evolution of large icy worlds hydrospheres when solutes are taken into account, compared to current models mainly using pure water. Based on our in-situ experimental measurements, we propose the existence of new liquid environments at greater depths and the possibility of solid state transport of solute through the high pressure ices
Nakayama, Masaki; Katano, Hiroaki; Sato, Haruki
2014-05-01
A precise determination of the critical temperature and density for technically important fluids would be possible on the basis of the digital image for the visual observation of the phase boundary in the vicinity of the critical point since the sensitivity and resolution are higher than those of naked eyes. In addition, the digital image can avoid the personal uncertainty of an observer. A strong density gradient occurs in a sample cell at the critical point due to gravity. It was carefully assessed to determine the critical density, where the density profile in the sample cell can be observed from the luminance profile of a digital image. The density-gradient profile becomes symmetric at the critical point. One of the best fluids, whose thermodynamic properties have been measured with the highest reliability among technically important fluids, would be carbon dioxide. In order to confirm the reliability of the proposed method, the critical temperature and density of carbon dioxide were determined using the digital image. The critical temperature and density values of carbon dioxide are ( and ( kg m, respectively. The critical temperature and density values agree with the existing best values within estimated uncertainties. The reliability of the method was confirmed. The critical pressure, 7.3795 MPa, corresponding to the determined critical temperature of 304.143 K is also proposed. A new set of parameters for the vapor-pressure equation is also provided.
High-pressure structural, elastic, and thermodynamic properties of zircon-type HoPO4 and TmPO4
International Nuclear Information System (INIS)
Gomis, O; Lavina, B; Rodríguez-Hernández, P; Muñoz, A; Errandonea, R; Errandonea, D; Bettinelli, M
2017-01-01
Zircon-type holmium phosphate (HoPO 4 ) and thulium phosphate (TmPO 4 ) have been studied by single-crystal x-ray diffraction and ab initio calculations. We report on the influence of pressure on the crystal structure, and on the elastic and thermodynamic properties. The equation of state for both compounds is accurately determined. We have also obtained information on the polyhedral compressibility which is used to explain the anisotropic axial compressibility and the bulk compressibility. Both compounds are ductile and more resistive to volume compression than to shear deformation at all pressures. Furthermore, the elastic anisotropy is enhanced upon compression. Finally, the calculations indicate that the possible causes that make the zircon structure unstable are mechanical instabilities and the softening of a silent B 1u mode. (paper)
Towards thermodynamical consistency of quasiparticle picture
International Nuclear Information System (INIS)
Biro, T.S.; Shanenko, A.A.; Toneev, V.D.; Research Inst. for Particle and Nuclear Physics, Hungarian Academy of Sciences, Budapest
2003-01-01
The purpose of the present article is to call attention to some realistic quasi-particle-based description of the quark/gluon matter and its consistent implementation in thermodynamics. A simple and transparent representation of the thermodynamical consistency conditions is given. This representation allows one to review critically and systemize available phenomenological approaches to the deconfinement problem with respect to their thermodynamical consistency. A particular attention is paid to the development of a method for treating the string screening in the dense matter of unbound color charges. The proposed method yields an integrable effective pair potential, which can be incorporated into the mean-field picture. The results of its application are in reasonable agreement with lattice data on the QCD thermodynamics [ru
Thermodynamic modelling and in-situ neutron diffraction investigation of the (Ce + Mg + Zn) system
International Nuclear Information System (INIS)
Zhu, Zhijun; Gharghouri, Michael A.; Medraj, Mamoun; Lee, Soo Yeol; Pelton, Arthur D.
2016-01-01
Highlights: • All phase diagram and thermodynamic data critically assessed for the (Ce + Mg + Zn) system. • All phases described by optimized thermodynamic models. • In-situ neutron diffraction performed to identify phases and transition temperatures. • Assessments of other (RE + Mg + Zn) systems have been carried out simultaneously. • The final product is a thermodynamic database for multicomponent (Mg + RE + Zn) systems. - Abstract: All available phase diagram data for the (Ce + Mg + Zn) system were critically assessed. In-situ neutron diffraction (ND) experiments were performed on selected samples to identify phases and transition temperatures. A critical thermodynamic evaluation and optimization of the (Ce + Mg + Zn) system were carried out and model parameters for the thermodynamic properties of all phases were obtained. The phase transformation behaviour of selected samples was well resolved from the ND experiments and experimental data were used to refine the thermodynamic model parameters.
Numerical tests of the electroweak phase transition and thermodynamics of the electroweak plasma
Csikor, Ferenc; Hein, J; Jaster, A; Montvay, István
1996-01-01
The finite temperature phase transition in the SU(2) Higgs model at a Higgs boson mass M_H \\simeq 34 GeV is studied in numerical simulations on four-dimensional lattices with time-like extensions up to L_t=5. The effects of the finite volume and finite lattice spacing on masses and couplings are studied in detail. The errors due to uncertainties in the critical hopping parameter are estimated. The thermodynamics of the electroweak plasma near the phase transition is investigated by determining the relation between energy density and pressure.
Directory of Open Access Journals (Sweden)
B. Hussain
2018-02-01
Full Text Available Mixture phase equilibrium and thermodynamic properties have a significant role in industry. Numerical analysis of flash calculation generates an appropriate solution for the problem. In this research, a comparison of Soave Redlich Kwong (SRK and Peng-Robinson (PR equations of state predicting the thermodynamic properties of a mixture of hydrocarbon and related compounds in a critical region at phase equilibrium is performed. By applying mathematical modeling of both equations of states, the behavior of binary gases mixtures is monitored. The numerical analysis of isothermal flash calculations is applied to study the pressure behavior with volume and mole fraction. The approach used in this research shows considerable convergence with experimental results available in the literature.
Brown, J. M.; Bollengier, O.; Vance, S.
2017-12-01
Water competes with silicates as the main constituent of solid bodies in the outer solar system. Ganymede and Titan, the Mercury-sized satellites of Jupiter and Saturn, are made up half of water present as massive hydrospheres where pressure can reach up to 1.5 GPa. Geophysical data and planetary models unequivocally support the existence of global aqueous oceans trapped in these hydrospheres. However, the extent of these oceans and their role in the processes governing the internal structure of these moons remain unresolved. At issue is the poor to non-existent characterization, at the relevant pressures, of the properties of the aqueous fluids of significance to the outer solar system (with notably the Na-Mg-Cl-SO4 salts found in primitive chondrites), forcing current models to rely on pure water only. Our team at the University of Washington has developed an experimental apparatus to acquire the speed of sound of aqueous solutions in the 0 - 0.7 GPa and 250 - 350 K pressure and temperature ranges covering most of the conditions of existence of these extra-terrestrial oceans. Speeds of sound measured over a grid of pressures and temperatures allow calculation of the thermodynamic quantities (G, ρ, μ...) required for planetary science. Early analysis of pure water samples indicates our experimental results are on par with (at lower pressures), or better than, the IAPWS water laboratory standard, with sound speeds determined to 0.02% over our entire pressure range. For the first time at the high pressures of interest for large icy moons, we achieved the exploration of H2O-NaCl, H2O-MgSO4, H2O-Na2SO4 and H2O-MgCl2 solutions, from dilute concentrations to saturation. We are now in the process of acquiring the first data for H2O-NaCl-MgSO4 mixtures. We will briefly present our experimental setup and the underlying sound speed theory, and will then compare our results for the four endmembers, with an emphasis on their different association behavior under pressure as
Energy Technology Data Exchange (ETDEWEB)
Yada, N. (Kanagawa Institute of Technology, Kanagawa (Japan)); Watanabe, K. (Keio University, Tokyo (Japan). Faculty of Science and Technology)
1991-12-25
The paper makes a correlation expressing dew- and bubble-point curves using measured values for seven binary refrigerant freon-mixtures. In most binary systems at the same temperature, the pressure shows a different value between in a saturated vapor state (dew-point pressure) and in a saturated liquid state (bubble-point pressure). The target is such correlation as has as simple a function form as possible and is able to estimate even near the critical point where it used to be difficult to estimate. The pressure difference between measured values of the dew- and bubble-point pressure and values calculated from Raoult's law showing an ideal mixture of fluid is expressed by a simple function form of reduced temperature Tr and molar fraction. Tr is thermodynamic temperature/critical temperature. Reproducibility of this correlation is less than {plus minus}3% of the pressure deviation. Concerning also the arbitary composition range and near the critical point, the dew- and bubble-point pressure can be calculated accurately. 24 refs., 4 figs., 5 tabs.
Overview of NASA supported Stirling thermodynamic loss research
International Nuclear Information System (INIS)
Tew, R.C.; Geng, S.M.
1994-01-01
The National Aeronautics and Space Administration (NASA) is funding research to characterize Stirling machine thermodynamic losses. NASA's primary goal is to improve Stirling design codes to support engine development for space and terrestrial power. However, much of the fundamental data is applicable to Stirling cooler and heat pump applications. The research results are reviewed. Much has been learned about oscillating-flow hydrodynamics, including laminar/turbulent transition, and tabulated data has been documented for further analysis. Now, with a better understanding of the oscillator-flow field, it is time to begin measuring the effects of oscillating flow and oscillating pressure level on heat transfer in heat exchanger flow passages and in cylinders. This critical phase of the work is just beginning
Energy Technology Data Exchange (ETDEWEB)
Vincze, A.; Sidawi, K.; Abdullah, R.; Baldock, M.; Saltanov, E.; Pioro, I., E-mail: andrei.vincze@uoit.net, E-mail: khalil.sidawi@uoit.net, E-mail: rand.abdullah@uoit.net, E-mail: matthew.baldock@uoit.net, E-mail: eugene.saltanov@uoit.ca, E-mail: igor.pioro@uoit.ca [Univ. of Ontario Inst. of Tech., Oshawa, ON (Canada)
2014-07-01
Current Nuclear Power Plants (NPPs) play a significant role in energy production around the world. All NPPs operating today employ a Rankine steam cycle for the conversion of thermal power to electricity. This paper will examine the steam cycle arrangement an experimental pressure channel reactor using Nuclear Steam Superheat (NSS) and compare it to two advanced reactor designs, the Advanced CANDU Reactor 1000 (ACR-1000) and the Advanced Boiling Water Reactor (ABWR) designs. The thermodynamic cycle layout and thermal efficiencies of the three reactor types will be discussed. (author)
Xu-Dong, Zhang; Wei, Jiang
2016-02-01
The effects of high pressure on lattice stability, mechanical and thermodynamic properties of L12 structure Al3Tm and Al3Lu are studied by first-principles calculations within the VASP code. The phonon dispersion curves and density of phonon states are calculated by using the PHONONPY code. Our results agree well with the available experimental and theoretical values. The vibrational properties indicate that Al3Tm and Al3Lu keep their dynamical stabilities in L12 structure up to 100 GPa. The elastic properties and Debye temperatures for Al3Tm and Al3Lu increase with the increase of pressure. The mechanical anisotropic properties are discussed by using anisotropic indices AG, AU, AZ, and the three-dimensional (3D) curved surface of Young’s modulus. The calculated results show that Al3Tm and Al3Lu are both isotropic at 0 GPa and anisotropic under high pressure. In the present work, the sound velocities in different directions for Al3Tm and Al3Lu are also predicted under high pressure. We also calculate the thermodynamic properties and provide the relationships between thermal parameters and temperature/pressure. These results can provide theoretical support for further experimental work and industrial applications. Project supported by the Scientific Technology Plan of the Educational Department of Liaoning Province and Liaoning Innovative Research Team in University, China (Grant No. LT2014004) and the Program for the Young Teacher Cultivation Fund of Shenyang University of Technology, China (Grant No. 005612).
Energy Technology Data Exchange (ETDEWEB)
Pitzer, K.S.
1979-09-01
It is shown that the properties of fully ionized aqueous electrolyte systems can be represented by relatively simple equations over wide ranges of composition. There are only a few systems for which data are available over the full range to fused salt. A simple equation commonly used for nonelectrolytes fits the measured vapor pressure of water reasonably well and further refinements are clearly possible. Over the somewhat more limited composition range up to saturation of typical salts such as NaCl, the equations representing thermodynamic properties with a Debye-Hueckel term plus second and third virial coefficients are very successful and these coefficients are known for nearly 300 electrolytes at room temperature. These same equations effectively predict the properties of mixed electrolytes. A stringent test is offered by the calculation of all of the solubility relationships of the system Na-K-Mg-Ca-Cl-So{sub 4}-H{sub 2}0 and the calculated results of Harvie and Weare show excellent agreement with
International Nuclear Information System (INIS)
Gomes de Azevedo, R.; Esperanca, J.M.S.S.; Szydlowski, J.; Visak, Z.P.; Pires, P.F.; Guedes, H.J.R.; Rebelo, L.P.N.
2005-01-01
The current study focuses on 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide, [bmim][NTf 2 ], and 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide, [hmim][NTf 2 ]. The objective is to study the influence of pressure as well as that of the cation's alkyl chain length on several properties of this type of ionic liquids. Speed of propagation of ultrasound waves and densities in pure ionic liquids (ILs) as a function of temperature and pressure have been determined. Several other thermodynamic properties such as compressibilities, expansivities and heat capacities have been obtained. Speed of sound measurements have been carried out in broad ranges of temperature (283 < T/K < 323) and pressure (0.1 < p/MPa < 150), using a non-intrusive microcell. Density measurements have been performed at broad ranges of temperature (298 < T/K < 333) and pressure (0.1 < p/MPa < 60) using a vibrating tube densimeter. The pressure dependence of heat capacities, which is generally mild, is highly dependent on the curvature of the temperature dependence of density
New methods of thermodynamics; Nouvelles methodes en thermodynamique
Energy Technology Data Exchange (ETDEWEB)
NONE
2001-07-01
This day, organized by the SFT French Society of Thermology, took stock on the new methods in the domain of the thermodynamics. Eight papers have been presented during this day: new developments of the thermodynamics in finite time; the optimal efficiency of energy converters; a version of non-equilibrium thermodynamics with entropy and information as positive and negative thermal change; the role of thermodynamics in process integration; application of the thermodynamics to critical nuclear accidents; the entropic analysis help in the case of charge and discharge state of an energy storage process; fluid flow threw a stable state in the urban hydraulic; a computer code for phase diagram prediction. (A.L.B.)
Thermodynamic calculations in ternary titanium–aluminium–manganese system
Directory of Open Access Journals (Sweden)
ANA I. KOSTOV
2008-04-01
Full Text Available Thermodynamic calculations in the ternary Ti–Al–Mn system are shown in this paper. The thermodynamic calculations were performed using the FactSage thermochemical software and database, with the aim of determining thermodynamic properties, such as activities, coefficient of activities, partial and integral values of the enthalpies and Gibbs energies of mixing and excess energies at two different temperatures: 2000 and 2100 K. Bearing in mind that no experimental data for the Ti–Al–Mn ternary system have been obtained or reported. The obtained results represent a good base for further thermodynamic analysis and may be useful as a comparison with some future critical experimental results and thermodynamic optimization of this system.
Homogeneous non-equilibrium two-phase critical flow model
International Nuclear Information System (INIS)
Schroeder, J.J.; Vuxuan, N.
1987-01-01
An important aspect of nuclear and chemical reactor safety is the ability to predict the maximum or critical mass flow rate from a break or leak in a pipe system. At the beginning of such a blowdown, if the stagnation condition of the fluid is subcooled or slightly saturated thermodynamic non-equilibrium exists in the downstream, e.g. the fluid becomes superheated to a degree determined by the liquid pressure. A simplified non-equilibrium model, explained in this report, is valid for rapidly decreasing pressure along the flow path. It presumes that fluid has to be superheated by an amount governed by physical principles before it starts to flash into steam. The flow is assumed to be homogeneous, i.e. the steam and liquid velocities are equal. An adiabatic flow calculation mode (Fanno lines) is employed to evaluate the critical flow rate for long pipes. The model is found to satisfactorily describe critical flow tests. Good agreement is obtained with the large scale Marviken tests as well as with small scale experiments. (orig.)
Thermodynamics of sublimation and solvation for bicyclo-derivatives of 1,3-thiazine
International Nuclear Information System (INIS)
Ol’khovich, Marina V.; Blokhina, Svetlana V.; Sharapova, Angelica V.; Perlovich, German L.; Proshin, Alexey N.
2013-01-01
Highlights: • Temperature dependencies of saturated vapor pressure of new bicyclo-derivatives were obtained. • Thermodynamic functions of sublimation and solvation were calculated. • The correlations between thermodynamic functions and molecular descriptors are discussed. - Abstract: Temperature dependencies of saturated vapor pressure of novel bicyclo-derivatives of 1,3-thiazine with methoxy- and carbonyl-substituents have been obtained by method of transference by means of an inert gas carrier. Thermodynamic functions of sublimation have been calculated. Correlations between thermodynamic functions of sublimation and thermophysical properties of the substances and molecular descriptors have been established. The enthalpies of solvation of compounds were calculated using the measured values of enthalpies of sublimation and of standard enthalpies of solution in hexane and buffer
Advanced Pressure Boundary Materials
Energy Technology Data Exchange (ETDEWEB)
Santella, Michael L [ORNL; Shingledecker, John P [ORNL
2007-01-01
Increasing the operating temperatures of fossil power plants is fundamental to improving thermal efficiencies and reducing undesirable emissions such as CO{sub 2}. One group of alloys with the potential to satisfy the conditions required of higher operating temperatures is the advanced ferritic steels such as ASTM Grade 91, 9Cr-2W, and 12Cr-2W. These are Cr-Mo steels containing 9-12 wt% Cr that have martensitic microstructures. Research aimed at increasing the operating temperature limits of the 9-12 wt% Cr steels and optimizing them for specific power plant applications has been actively pursued since the 1970's. As with all of the high strength martensitic steels, specifying upper temperature limits for tempering the alloys and heat treating weldments is a critical issue. To support this aspect of development, thermodynamic analysis was used to estimate how this critical temperature, the A{sub 1} in steel terminology, varies with alloy composition. The results from the thermodynamic analysis were presented to the Strength of Weldments subgroup of the ASME Boiler & Pressure Vessel Code and are being considered in establishing maximum postweld heat treatment temperatures. Experiments are also being planned to verify predictions. This is part of a CRADA project being done with Alstom Power, Inc.
Thermodynamic analysis of PBMR plant
International Nuclear Information System (INIS)
Sen, S.; Kadiroglu, O.K.
2002-01-01
The thermodynamic analysis of a PBMR is presented for various pressures and temperatures values. The design parameters of the components of the power plant are calculated and an optimum cycle for the maximum thermal efficiency is sought for. (author)
Diffuse interfacelets in transcritical flows of propellants into high-pressure combustors
Urzay, Javier; Jofre, Lluis
2017-11-01
Rocket engines and new generations of high-power jet engines and diesel engines oftentimes involve the injection of one or more reactants at subcritical temperatures into combustor environments at high pressures, and more particularly, at pressures higher than those corresponding to the critical points of the individual components of the mixture, which typically range from 13 to 50 bars for most propellants. This class of trajectories in the thermodynamic space has been traditionally referred to as transcritical. Under particular conditions often found in hydrocarbon-fueled chemical propulsion systems, and despite the prevailing high pressures, the flow in the combustor may contain regions close to the injector where a diffuse interface is formed in between the fuel and oxidizer streams that is sustained by surface-tension forces as a result of the elevation of the critical pressure of the mixture. This talk describes progress towards modeling these effects in the conservation equations. Funded by the US Department of Energy.
Applied Thermodynamics: Grain Boundary Segregation
Directory of Open Access Journals (Sweden)
Pavel Lejček
2014-03-01
Full Text Available Chemical composition of interfaces—free surfaces and grain boundaries—is generally described by the Langmuir–McLean segregation isotherm controlled by Gibbs energy of segregation. Various components of the Gibbs energy of segregation, the standard and the excess ones as well as other thermodynamic state functions—enthalpy, entropy and volume—of interfacial segregation are derived and their physical meaning is elucidated. The importance of the thermodynamic state functions of grain boundary segregation, their dependence on volume solid solubility, mutual solute–solute interaction and pressure effect in ferrous alloys is demonstrated.
Hamm, L. L.; Vanbrunt, V.
1982-08-01
The numerical solution to the ordinary differential equation which describes the high-pressure vapor-liquid equilibria of a binary system where one of the components is supercritical and exists as a noncondensable gas in the pure state is considered with emphasis on the implicit Runge-Kuta and orthogonal collocation methods. Some preliminary results indicate that the implicit Runge-Kutta method is superior. Due to the extreme nonlinearity of thermodynamic properties in the region near the critical locus, and extended cubic spline fitting technique is devised for correlating the P-x data. The least-squares criterion is employed in smoothing the experimental data. The technique could easily be applied to any thermodynamic data by changing the endpoint requirements. The volumetric behavior of the systems must be given or predicted in order to perform thermodynamic consistency tests. A general procedure is developed for predicting the volumetric behavior required and some indication as to the expected limit of accuracy is given.
Kimura, Takeru; Kayukawa, Yohei; Miyamoto, Hiroyuki; Saito, Kiyoshi
2017-08-01
This study presents the experimental measurement of the pρ T properties and critical parameters of a low GWP type refrigerant, trans-1,1,1,3-Tetrafluorobut-2-ene (HFO-1354mzy(E)). The sample purity of the substance was 99 area %. p ρ T property measurements and visual observations of the meniscus of HFO-1354mzy(E) were carried out using a metal-bellows volumometer with an optical cell. The critical temperature was determined by observation of the critical opalescence. The critical pressure and critical density were determined as the inflection point of the isothermal p ρ T property data at the critical temperature. For more precise clarification of the thermodynamic surface in the vicinity of the critical point, additional p ρ T property measurements were carried out on three isotherms in the supercritical region. The expanded uncertainties (k = 2) in the temperature, pressure, and density measurements were estimated to be less than 3 mK, 1.2 kPa, and 0.32 \\hbox {kg} \\cdot \\hbox {m}^{-3}, respectively. The expanded uncertainties of the critical parameters were estimated to be less than 13 mK, 1.4 kPa, and 2.3 \\hbox {kg} \\cdot \\hbox {m}^{-3}, respectively. These values are the first reported for HFO-1354mzy(E) and are necessary for the development of its equation of state in the near future.
Critical review of use of high pressure saturated steam turbine economizers in nuclear power plants
International Nuclear Information System (INIS)
Urbanek, J.
1981-01-01
In the high-pressure part of the turbine drops of moisture condensate, which causes erosion and has negative impact on the service-life of the turbine and on its thermodynamic efficiency. Various designs have been put forward to eliminate moisture. A good combination is moisture separation combined with the offtake of steam for the regeneration of feed water or for the steam re-heater. As concerns the high-pressure component of the turbine it is best to offtake steam for the feed water heater and for heating the steam between the high- and low-pressure components of the turbine. The connections of the heater and re-heater in diagrams of various manufacturers are evaluated and compared. It appears to be uneconomical to use the heater in cases where feed water would be heated to temperature considerably below its optimal value. (M.D.)
Reducing the incidence of pressure ulcers in critical care units: a 4-year quality improvement.
Richardson, Annette; Peart, Joanna; Wright, Stephen E; McCullagh, Iain J
2017-06-01
Critical care patients often have several risk factors for pressure ulceration and implementing prevention interventions have been shown to decrease risk. We identified a high incidence of pressure ulcers in the four adult critical care units in our organization. Therefore, avoiding pressure ulceration was an important quality priority. We undertook a quality improvement programme aimed at reducing the incidence of pressure ulceration using an evidence-based bundle approach. A bundle of technical and non-technical interventions were implemented supported by clinical leadership on each unit. Important components were evidence appraisals; changes to mattresses; focussed risk assessment alongside mandating patients at very high risk to be repositioned two hourly; and staff training to increase awareness of how to prevent pressure ulcers. Pressure ulcer numbers, incidence and categories were collected continuously and monitored monthly by unit staff. Pressure ulcer rates reduced significantly from 8.08/100 patient admissions to 2.97/100 patient admissions, an overall relative rate reduction of 63% over 4 years. The greatest reduction was seen in the most severe category of pressure ulceration. The average estimated cost saving was £2.6 million (range £2.1-£3.1). A quality improvement programme including technical and non-technical interventions, data feedback to staff and clinical leadership was associated with a sustained reduction in the incidence of pressure ulceration in the critically ill. Strategies used in this programme may be transferable to other critical care units to bring more widespread patient benefit. © The Author 2017. Published by Oxford University Press in association with the International Society for Quality in Health Care. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com
Satoh, Katsuhiko
2013-03-07
Thermodynamic parameter Γ and thermodynamic scaling parameter γ for low-frequency relaxation time, which characterize flip-flop motion in a nematic phase, were verified by molecular dynamics simulation with a simple potential based on the Maier-Saupe theory. The parameter Γ, which is the slope of the logarithm for temperature and volume, was evaluated under various conditions at a wide range of temperatures, pressures, and volumes. To simulate thermodynamic scaling so that experimental data at isobaric, isothermal, and isochoric conditions can be rescaled onto a master curve with the parameters for some liquid crystal (LC) compounds, the relaxation time was evaluated from the first-rank orientational correlation function in the simulations, and thermodynamic scaling was verified with the simple potential representing small clusters. A possibility of an equivalence relationship between Γ and γ determined from the relaxation time in the simulation was assessed with available data from the experiments and simulations. In addition, an argument was proposed for the discrepancy between Γ and γ for some LCs in experiments: the discrepancy arises from disagreement of the value of the order parameter P2 rather than the constancy of relaxation time τ1(*) on pressure.
On thermodynamics of methane+carbonaceous materials adsorption
Rahman, Kazi Afzalur
2012-01-01
This study presents the theoretical frameworks for the thermodynamic quantities namely the heat of adsorption, specific heat capacity, entropy, and enthalpy for the adsorption of methane onto various carbonaceous materials. The proposed theoretical frameworks are developed from the rigor of thermodynamic property surfaces of a single component adsorbate-adsorbent system and by incorporating the micropore filling theory approach, where the effect of adsorbed phase volume is considered. The abovementioned thermodynamic properties are quantitatively evaluated from the experimental uptake data for methane adsorption onto activated carbons such as Maxsorb III at temperatures ranging from 120 to 350 K and pressures up to 25 bar. Employing the proposed thermodynamic approaches, this paper shows the thermodynamic maps of the charge and discharge processes of adsorbed natural gas (ANG) storage system for understanding the behaviors of natural gas in ANG vessel. © 2011 Elsevier Ltd. All rights reserved.
Structure and thermodynamics of core-softened models for alcohols
International Nuclear Information System (INIS)
Munaò, Gianmarco; Urbic, Tomaz
2015-01-01
The phase behavior and the fluid structure of coarse-grain models for alcohols are studied by means of reference interaction site model (RISM) theory and Monte Carlo simulations. Specifically, we model ethanol and 1-propanol as linear rigid chains constituted by three (trimers) and four (tetramers) partially fused spheres, respectively. Thermodynamic properties of these models are examined in the RISM context, by employing closed formulæ for the calculation of free energy and pressure. Gas-liquid coexistence curves for trimers and tetramers are reported and compared with already existing data for a dimer model of methanol. Critical temperatures slightly increase with the number of CH 2 groups in the chain, while critical pressures and densities decrease. Such a behavior qualitatively reproduces the trend observed in experiments on methanol, ethanol, and 1-propanol and suggests that our coarse-grain models, despite their simplicity, can reproduce the essential features of the phase behavior of such alcohols. The fluid structure of these models is investigated by computing radial distribution function g ij (r) and static structure factor S ij (k); the latter shows the presence of a low−k peak at intermediate-high packing fractions and low temperatures, suggesting the presence of aggregates for both trimers and tetramers
Directory of Open Access Journals (Sweden)
N. Wei
2015-12-01
Full Text Available In this work, the elastic and thermodynamic properties of Pt_{3}Al under high pressure are investigated using density functional theory within the generalized gradient approximation. The results of bulk modulus and elastic constants at zero pressure are in good agreement with the available theoretical and experimental values. Under high pressure, all the elastic constants meet the corresponding mechanical stability criteria, meaning that Pt_{3}Al possesses mechanical stability. In addition, the elastic constants and elastic modulus increase linearly with the applied pressure. According to the Poisson's ratio ν and elastic modulus ratio (B/G, Pt_{3}Al alloy is found to be ductile, and higher pressure can significantly enhance the ductility. Those indicate that the elastic properties of Pt_{3}Al will be improved under high pressure. Through the quasi-harmonic Debye model, we first successfully report the variations of the Debye temperature Θ_{D}, specific heats C_{P}, thermal expansion coefficient α, and Grüneisen parameter γ under pressure range from 0 to 100 GPa and temperature range from 0 to 1000 K.
Flemings, P. B.; Saffer, D. M.
2016-12-01
We predict pore pressure from porosity measurements at ODP Sites 1174 and 808 in the Nankai Accretionary prism, offshore Japan. For a range of friction angles (5-30 degrees), we estimate that the pore pressure ratio (λ*) ranges from 0.5 to 0.8: the pore pressure supports 50% to 80% of the overburden. Higher friction angles result in higher pressures. For the majority of the scenarios, pressures within the prism parallel the lithostat and are greater than the pressures beneath it. Our results support previous qualitative interpretations at Nankai and elsewhere suggesting that lower porosity above the décollement than below reflects higher mean effective stress there. By coupling a critical state soil model (Modified Cam Clay), which describes porosity as a function of mean and deviator stress, with a stress model that considers the difference in stress states above and below the décollement, we quantitatively show that the prism porosities record significant overpressure despite their lower porosity. As the soil is consumed by the advancing prism, changes in both mean and shear stress drive overpressure generation. Even in the extreme case where only change in mean stress is considered (a vertical end cap model), significant overpressures are generated. The high pressures we predict require an effective friction coefficient (µb') at the décollement of 0.023-0.038. Assuming that the pore pressure at the décollement lies between the values we report for the wedge and the underthrusting sediments, these effective friction coefficients correspond to intrinsic friction coefficients of µb= 0.08-0.38 (f = 4.6 - 21°). These values are comparable to friction coefficients of 0.1-0.4 reported for clay-dominated fault zones in a wide range of settings. By coupling the critical wedge model with an appropriate constitutive model, we present a systematic approach to predict pressure in thrust systems.
Directory of Open Access Journals (Sweden)
Jie Ren
2014-09-01
Full Text Available In high-pressure dynamic thermodynamic processes, the pressure is much higher than the air critical pressure, and the temperature can deviate significantly from the Boyle temperature. In such situations, the thermo-physical properties and pneumatic performance can’t be described accurately by the ideal gas law. This paper proposes an approach to evaluate the pneumatic performance of a high-pressure air catapult launch system, in which esidual functions are used to compensate the thermal physical property uncertainties of caused by real gas effects. Compared with the Nelson-Obert generalized compressibility charts, the precision of the improved virial equation of state is better than Soave-Redlich-Kwong (S-R-K and Peng-Robinson (P-R equations for high pressure air. In this paper, the improved virial equation of state is further used to establish a compressibility factor database which is applied to evaluate real gas effects. The specific residual thermodynamic energy and specific residual enthalpy of the high-pressure air are also derived using the modified corresponding state equation and improved virial equation of state which are truncated to the third virial coefficient. The pneumatic equations are established on the basis of the derived residual functions. The comparison of the numerical results shows that the real gas effects are strong, and the pneumatic performance analysis indicates that the real dynamic thermodynamic process is obviously different from the ideal one.
Phase transition and thermodynamic stability of topological black holes in Hořava-Lifshitz gravity
Ma, Meng-Sen; Zhao, Ren; Liu, Yan-Song
2017-08-01
On the basis of horizon thermodynamics, we study the thermodynamic stability and P-V criticality of topological black holes constructed in Hořava-Lifshitz (HL) gravity without the detailed-balance condition (with general ɛ). In the framework of horizon thermodynamics, we do not need the concrete black hole solution (the metric function) and the concrete matter fields. It is shown that the HL black hole for k=0 is always thermodynamically stable. For k=1 , the thermodynamic behaviors and P-V criticality of the HL black hole are similar to those of RN-AdS black hole for some \
Thermodynamic properties of potassium chloride aqueous solutions
Zezin, Denis; Driesner, Thomas
2017-04-01
Potassium chloride is a ubiquitous salt in natural fluids, being the second most abundant dissolved salt in many geological aqueous solutions after sodium chloride. It is a simple solute and strong electrolyte easily dissociating in water, however the thermodynamic properties of KCl aqueous solutions were never correlated with sufficient accuracy for a wide range of physicochemical conditions. In this communication we propose a set of parameters for a Pitzer-type model which allows calculation of all necessary thermodynamic properties of KCl solution, namely excess Gibbs free energy and derived activity coefficient, apparent molar enthalpy, heat capacity and volume, as well as osmotic coefficient and activity of water in solutions. The system KCl-water is one of the best studied aqueous systems containing electrolytes. Although extensive experimental data were collected for thermodynamic properties of these solutions over the years, the accurate volumetric data became available only recently, thus making possible a complete thermodynamic formulation including a pressure dependence of excess Gibbs free energy and derived properties of the KCl-water liquids. Our proposed model is intended for calculation of major thermodynamic properties of KCl aqueous solutions at temperatures ranging from freezing point of a solution to 623 K, pressures ranging from saturated water vapor up to 150 MPa, and concentrations up to the salt saturation. This parameterized model will be further implemented in geochemical software packages and can facilitate the calculation of aqueous equilibrium for reactive transport codes.
Energy Technology Data Exchange (ETDEWEB)
Song, Ting, E-mail: songting_lzjtu@163.com [State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals, Lanzhou University of Technology, Lanzhou 730050 (China); College of Material Science and Engineering, Lanzhou University of Technology, Lanzhou 730050 (China); School of Mathematics and Physics, Lanzhou Jiaotong University, Lanzhou 730070 (China); Sun, Xiao-Wei [School of Mathematics and Physics, Lanzhou Jiaotong University, Lanzhou 730070 (China); Tian, Jun-Hong [School of Mathematics and Physics, Lanzhou Jiaotong University, Lanzhou 730070 (China); Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065 (China); Wei, Xiao-Ping; Wan, Gui-Xin [School of Mathematics and Physics, Lanzhou Jiaotong University, Lanzhou 730070 (China); Ma, Qin, E-mail: maqin_lut@yeah.net [State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals, Lanzhou University of Technology, Lanzhou 730050 (China); College of Material Science and Engineering, Lanzhou University of Technology, Lanzhou 730050 (China)
2017-04-15
In the frame of density functional theory, first-principles calculations based on generalized gradient approximation and quasi-harmonic Debye approximation model in which the phononic effects are taken into account have been carried out to investigate the structural, electronic, magnetic, and thermodynamic properties of full-Heusler alloy Mn{sub 2}RuGe in CuHg{sub 2}Ti-type structure in the pressure range of 0–50 GPa. Present calculations predict that Mn{sub 2}RuGe is a ferrimagnet with an optimized lattice parameter of 5.854 Å. The calculated total magnetic moment of 2.01 μ{sub B} per formula unit is very close to integer value and agree well with the Slater-Pauling rule, where the partial spin moments of Mn (A) and Mn (B) which mainly contribute to the total magnetic moment are 2.66 μ{sub B} and −0.90 μ{sub B}, respectively. In the study of the energy band structures and density of states, Mn{sub 2}RuGe exhibits half-metallicity with an indirect gap of 0.235 eV in the spin-down channels, and the shifting of bands towards higher energies in spin-down channel under high pressure. Meanwhile, the high-pressure thermodynamic properties of Mn{sub 2}RuGe, such as the pressure-volume-temperature relationship, bulk modulus, thermal expansivity, heat capacity, Debye temperature, and Grüneisen parameter are evaluated systematically in the temperature range of 0–900 K. This set of data is considered as the useful information to understand the high-pressure and high-temperature properties for the Mn{sub 2}RuZ-type Heusler alloy family.
International Nuclear Information System (INIS)
Mohtaram, Soheil; Chen, Wen; Zargar, T.; Lin, Ji
2017-01-01
Highlights: • Energy exergy analysis is conducted to find the effects of RP. • EES software is utilized to perform the detailed energy-exergy analyses. • Effects investigated through energy and exergy destruction, enthalpy, yields, etc. • Detailed results are reported showing the performance of gas and combined cycle. - Abstract: The purpose of this study is to investigate the effect of compressor pressure ratio (RP) on the thermodynamic performances of ammonia-water combined cycle through energy and exergy destruction, enthalpy temperature, yields, and flow velocity. The energy-exergy analysis is conducted on the ammonia water combined cycle and the Rankine cycle, respectively. Engineering Equation Solver (EES) software is utilized to perform the detailed analyses. Values and ratios regarding heat drop and exergy loss are presented in separate tables for different equipments. The results obtained by the energy-exergy analysis indicate that by increasing the pressure ratio compressor, exergy destruction of high-pressure compressors, intercooler, gas turbine and the special produced work of gas turbine cycle constantly increase and the exergy destruction of recuperator, in contrast, decreases continuously. In addition, the least amount of input fuel into the combined cycle is observed when the pressure ratio is no less than 7.5. Subsequently, the efficiency of the cycle in gas turbine and combined cycle is reduced because the fuel input into the combined cycle is increased.
Thermodynamic data-base for metal fluorides
Energy Technology Data Exchange (ETDEWEB)
Yoo, Jae Hyung; Lee, Byung Gik; Kang, Young Ho and others
2001-05-01
This study is aimed at collecting useful data of thermodynamic properties of various metal fluorides. Many thermodynamic data for metal fluorides are needed for the effective development, but no report of data-base was published. Accordingly, the objective of this report is to rearrange systematically the existing thermodynamic data based on metal fluorides and is to use it as basic data for the development of pyrochemical process. The physicochemical properties of various metal fluorides and metals were collected from literature and such existing data base as HSC code, TAPP code, FACT code, JANAF table, NEA data-base, CRC handbook. As major contents of the thermodynamic data-base, the physicochemical properties such as formation energy, viscosity, density, vapor pressure, etc. were collected. Especially, some phase diagrams of eutectic molten fluorides are plotted and thermodynamic data of liquid metals are also compiled. In the future, the technical report is to be used as basic data for the development of the pyrochemical process which is being carried out as a long-term nuclear R and D project.
Thermodynamic data-base for metal fluorides
International Nuclear Information System (INIS)
Yoo, Jae Hyung; Lee, Byung Gik; Kang, Young Ho and others
2001-05-01
This study is aimed at collecting useful data of thermodynamic properties of various metal fluorides. Many thermodynamic data for metal fluorides are needed for the effective development, but no report of data-base was published. Accordingly, the objective of this report is to rearrange systematically the existing thermodynamic data based on metal fluorides and is to use it as basic data for the development of pyrochemical process. The physicochemical properties of various metal fluorides and metals were collected from literature and such existing data base as HSC code, TAPP code, FACT code, JANAF table, NEA data-base, CRC handbook. As major contents of the thermodynamic data-base, the physicochemical properties such as formation energy, viscosity, density, vapor pressure, etc. were collected. Especially, some phase diagrams of eutectic molten fluorides are plotted and thermodynamic data of liquid metals are also compiled. In the future, the technical report is to be used as basic data for the development of the pyrochemical process which is being carried out as a long-term nuclear R and D project
Thermodynamic fluctuations within the Gibbs and Einstein approaches
International Nuclear Information System (INIS)
Rudoi, Yurii G; Sukhanov, Alexander D
2000-01-01
A comparative analysis of the descriptions of fluctuations in statistical mechanics (the Gibbs approach) and in statistical thermodynamics (the Einstein approach) is given. On this basis solutions are obtained for the Gibbs and Einstein problems that arise in pressure fluctuation calculations for a spatially limited equilibrium (or slightly nonequilibrium) macroscopic system. A modern formulation of the Gibbs approach which allows one to calculate equilibrium pressure fluctuations without making any additional assumptions is presented; to this end the generalized Bogolyubov - Zubarev and Hellmann - Feynman theorems are proved for the classical and quantum descriptions of a macrosystem. A statistical version of the Einstein approach is developed which shows a fundamental difference in pressure fluctuation results obtained within the context of two approaches. Both the 'genetic' relation between the Gibbs and Einstein approaches and the conceptual distinction between their physical grounds are demonstrated. To illustrate the results, which are valid for any thermodynamic system, an ideal nondegenerate gas of microparticles is considered, both classically and quantum mechanically. Based on the results obtained, the correspondence between the micro- and macroscopic descriptions is considered and the prospects of statistical thermodynamics are discussed. (reviews of topical problems)
Fluorene: An extended experimental thermodynamic study
International Nuclear Information System (INIS)
Monte, Manuel J.S.; Pinto, Sónia P.; Lobo Ferreira, Ana I.M.C.; Amaral, Luísa M.P.F.; Freitas, Vera L.S.; Ribeiro da Silva, Maria D.M.C.
2012-01-01
Highlights: ► Experimental results of an extended thermodynamic study on fluorene are presented. ► Enthalpy of combustion and vapor pressures of liquid and crystalline phase were measured. ► Enthalpy of sublimation was derived from three different experimental methods. ► New values of enthalpies of sublimation and of formation of fluorene are recommended. - Abstract: This work reports new experimental thermodynamic results on fluorene. Vapor pressures of both crystalline and liquid phases were measured using a pressure gauge (capacitance diaphragm manometer) and Knudsen effusion methods over a wide temperature range (292.20 to 412.16) K yielding accurate determination of enthalpy and entropy of sublimation and of vaporization. The enthalpy of sublimation was also determined using Calvet microcalorimetry. The enthalpy of fusion was derived from vapor pressure results and from d.s.c. experiments. Static bomb calorimetry was used to determine the enthalpy of combustion of fluorene from which the standard enthalpy of formation in the crystalline phase was calculated. The enthalpy of formation in the gaseous phase was calculated combining the result derived for the crystalline phase with the enthalpy of sublimation.
Gravitational entropy and thermodynamics away from the horizon
Energy Technology Data Exchange (ETDEWEB)
Brustein, Ram, E-mail: ramyb@bgu.ac.il [Department of Physics, Ben-Gurion University, Beer-Sheva 84105 (Israel); CAS, Ludwig-Maximilians-Universitaet Muenchen, 80333 Muenchen (Germany); Medved, A.J.M., E-mail: j.medved@ru.ac.za [Department of Physics and Electronics, Rhodes University, Grahamstown 6140 (South Africa)
2012-08-29
We define, by an integral of geometric quantities over a spherical shell of arbitrary radius, an invariant gravitational entropy. This definition relies on defining a gravitational energy and pressure, and it reduces at the horizon of both black branes and black holes to Wald's Noether charge entropy. We support the thermodynamic interpretation of the proposed entropy by showing that, for some cases, the field theory duals of the entropy, energy and pressure are the same as the corresponding quantities in the field theory. In this context, the Einstein equations are equivalent to the field theory thermodynamic relation TdS=dE+PdV supplemented by an equation of state.
Thermodynamics of de Sitter universes
International Nuclear Information System (INIS)
Huang Chaoguang; Liu Liao; Wang Bobo
2002-01-01
It is shown that the first law of thermodynamics can be applied to the de Sitter universe to relate its vacuum energy, pressure, entropy of horizon, chemical potential, etc., when the cosmological constant changes due to the fluctuation of the vacuum or other reasons. The second law should be reformulated in the form that the spontaneous decay of the vacuum never makes the entropy of the de Sitter universe decrease. The third law of thermodynamics, applying to the de Sitter universe, implies that the cosmological constant cannot reach zero by finite physical processes. The relation to the holographic principle is also briefly discussed
Influence of Thermodynamic Effect on Blade Load in a Cavitating Inducer
Directory of Open Access Journals (Sweden)
Kengo Kikuta
2010-01-01
Full Text Available Distribution of the blade load is one of the design parameters for a cavitating inducer. For experimental investigation of the thermodynamic effect on the blade load, we conducted experiments in both cold water and liquid nitrogen. The thermodynamic effect on cavitation notably appears in this cryogenic fluid although it can be disregarded in cold water. In these experiments, the pressure rise along the blade tip was measured. In water, the pressure increased almost linearly from the leading edge to the trailing edge at higher cavitation number. After that, with a decrease of cavitation number, pressure rise occurred only near the trailing edge. On the other hand, in liquid nitrogen, the pressure distribution was similar to that in water at a higher cavitation number, even if the cavitation number as a cavitation parameter decreased. Because the cavitation growth is suppressed by the thermodynamic effect, the distribution of the blade load does not change even at lower cavitation number. By contrast, the pressure distribution in liquid nitrogen has the same tendency as that in water if the cavity length at the blade tip is taken as a cavitation indication. From these results, it was found that the shift of the blade load to the trailing edge depended on the increase of cavity length, and that the distribution of blade load was indicated only by the cavity length independent of the thermodynamic effect.
Thermodynamic anomaly in magnesium hydroxide decomposition
International Nuclear Information System (INIS)
Reis, T.A.
1983-08-01
The Origin of the discrepancy in the equilibrium water vapor pressure measurements for the reaction Mg(OH) 2 (s) = MgO(s) + H 2 O(g) when determined by Knudsen effusion and static manometry at the same temperature was investigated. For this reaction undergoing continuous thermal decomposition in Knudsen cells, Kay and Gregory observed that by extrapolating the steady-state apparent equilibrium vapor pressure measurements to zero-orifice, the vapor pressure was approx. 10 -4 of that previously established by Giauque and Archibald as the true thermodynamic equilibrium vapor pressure using statistical mechanical entropy calculations for the entropy of water vapor. This large difference in vapor pressures suggests the possibility of the formation in a Knudsen cell of a higher energy MgO that is thermodynamically metastable by about 48 kJ / mole. It has been shown here that experimental results are qualitatively independent of the type of Mg(OH) 2 used as a starting material, which confirms the inferences of Kay and Gregory. Thus, most forms of Mg(OH) 2 are considered to be the stable thermodynamic equilibrium form. X-ray diffraction results show that during the course of the reaction only the equilibrium NaCl-type MgO is formed, and no different phases result from samples prepared in Knudsen cells. Surface area data indicate that the MgO molar surface area remains constant throughout the course of the reaction at low decomposition temperatures, and no significant annealing occurs at less than 400 0 C. Scanning electron microscope photographs show no change in particle size or particle surface morphology. Solution calorimetric measurements indicate no inherent hgher energy content in the MgO from the solid produced in Knudsen cells. The Knudsen cell vapor pressure discrepancy may reflect the formation of a transient metastable MgO or Mg(OH) 2 -MgO solid solution during continuous thermal decomposition in Knudsen cells
Quantum thermodynamics of nanoscale steady states far from equilibrium
Taniguchi, Nobuhiko
2018-04-01
We develop an exact quantum thermodynamic description for a noninteracting nanoscale steady state that couples strongly with multiple reservoirs. We demonstrate that there exists a steady-state extension of the thermodynamic function that correctly accounts for the multiterminal Landauer-Büttiker formula of quantum transport of charge, energy, or heat via the nonequilibrium thermodynamic relations. Its explicit form is obtained for a single bosonic or fermionic level in the wide-band limit, and corresponding thermodynamic forces (affinities) are identified. Nonlinear generalization of the Onsager reciprocity relations are derived. We suggest that the steady-state thermodynamic function is also capable of characterizing the heat current fluctuations of the critical transport where the thermal fluctuations dominate. Also, the suggested nonequilibrium steady-state thermodynamic relations seemingly persist for a spin-degenerate single level with local interaction.
Thermodynamics of Hydrogen Production from Dimethyl Ether Steam Reforming and Hydrolysis
Energy Technology Data Exchange (ETDEWEB)
T.A. Semelsberger
2004-10-01
The thermodynamic analyses of producing a hydrogen-rich fuel-cell feed from the process of dimethyl ether (DME) steam reforming were investigated as a function of steam-to-carbon ratio (0-4), temperature (100 C-600 C), pressure (1-5 atm), and product species: acetylene, ethanol, methanol, ethylene, methyl-ethyl ether, formaldehyde, formic acid, acetone, n-propanol, ethane and isopropyl alcohol. Results of the thermodynamic processing of dimethyl ether with steam indicate the complete conversion of dimethyl ether to hydrogen, carbon monoxide and carbon dioxide for temperatures greater than 200 C and steam-to-carbon ratios greater than 1.25 at atmospheric pressure (P = 1 atm). Increasing the operating pressure was observed to shift the equilibrium toward the reactants; increasing the pressure from 1 atm to 5 atm decreased the conversion of dimethyl ether from 99.5% to 76.2%. The order of thermodynamically stable products in decreasing mole fraction was methane, ethane, isopropyl alcohol, acetone, n-propanol, ethylene, ethanol, methyl-ethyl ether and methanol--formaldehyde, formic acid, and acetylene were not observed. The optimal processing conditions for dimethyl ether steam reforming occurred at a steam-to-carbon ratio of 1.5, a pressure of 1 atm, and a temperature of 200 C. Modeling the thermodynamics of dimethyl ether hydrolysis (with methanol as the only product considered), the equilibrium conversion of dimethyl ether is limited. The equilibrium conversion was observed to increase with temperature and steam-to-carbon ratio, resulting in a maximum dimethyl ether conversion of approximately 68% at a steam-to-carbon ratio of 4.5 and a processing temperature of 600 C. Thermodynamically, dimethyl ether processed with steam can produce hydrogen-rich fuel-cell feeds--with hydrogen concentrations exceeding 70%. This substantiates dimethyl ether as a viable source of hydrogen for PEM fuel cells.
Thermodynamics of freezing and melting
DEFF Research Database (Denmark)
Pedersen, Ulf Rørbæk; Costigliola, Lorenzo; Bailey, Nicholas
2016-01-01
phases at a single thermodynamic state point provide the basis for calculating the pressure, density and entropy of fusion as functions of temperature along the melting line, as well as the variation along this line of the reduced crystalline vibrational mean-square displacement (the Lindemann ratio...
Directory of Open Access Journals (Sweden)
R. Yang
2017-12-01
Full Text Available The optical, elastic anisotropic and thermodynamic properties of TiN in the NaCl (B1 structure are analyzed in detail in the temperature range from 0 to 2000 K and the pressure range from 0 to 20 GPa. From the calculated dielectric constants, a first order isostructural phase transition between 29 and 30 GPa is found for TiN. The absorption spectra exhibit high values ranging from the far infrared region to the ultra-violet one. The anisotropy value of Young's modulus of TiN is smaller than that of c-BN at 0 GPa and the anisotropy of TiN clearly increases with an increase of pressure. The effects of pressure and temperature on the bulk modulus, Grüneisen parameter, Gibbs free energy, and Debye temperature are significant. The Grüneisen parameter of TiN is much larger than that of c-BN. At temperatures below 1000 K, TiN's heat capacity is much larger than that of c-BN.
Extrinsic and intrinsic curvatures in thermodynamic geometry
Energy Technology Data Exchange (ETDEWEB)
Hosseini Mansoori, Seyed Ali, E-mail: shossein@bu.edu [Department of Physics, Boston University, 590 Commonwealth Ave., Boston, MA 02215 (United States); Department of Physics, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Mirza, Behrouz, E-mail: b.mirza@cc.iut.ac.ir [Department of Physics, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Sharifian, Elham, E-mail: e.sharifian@ph.iut.ac.ir [Department of Physics, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)
2016-08-10
We investigate the intrinsic and extrinsic curvatures of a certain hypersurface in thermodynamic geometry of a physical system and show that they contain useful thermodynamic information. For an anti-Reissner–Nordström-(A)de Sitter black hole (Phantom), the extrinsic curvature of a constant Q hypersurface has the same sign as the heat capacity around the phase transition points. The intrinsic curvature of the hypersurface can also be divergent at the critical points but has no information about the sign of the heat capacity. Our study explains the consistent relationship holding between the thermodynamic geometry of the KN-AdS black holes and those of the RN (J-zero hypersurface) and Kerr black holes (Q-zero hypersurface) ones [1]. This approach can easily be generalized to an arbitrary thermodynamic system.
Extrinsic and intrinsic curvatures in thermodynamic geometry
International Nuclear Information System (INIS)
Hosseini Mansoori, Seyed Ali; Mirza, Behrouz; Sharifian, Elham
2016-01-01
We investigate the intrinsic and extrinsic curvatures of a certain hypersurface in thermodynamic geometry of a physical system and show that they contain useful thermodynamic information. For an anti-Reissner–Nordström-(A)de Sitter black hole (Phantom), the extrinsic curvature of a constant Q hypersurface has the same sign as the heat capacity around the phase transition points. The intrinsic curvature of the hypersurface can also be divergent at the critical points but has no information about the sign of the heat capacity. Our study explains the consistent relationship holding between the thermodynamic geometry of the KN-AdS black holes and those of the RN (J-zero hypersurface) and Kerr black holes (Q-zero hypersurface) ones [1]. This approach can easily be generalized to an arbitrary thermodynamic system.
Protein Denaturation on p-T Axes--Thermodynamics and Analysis.
Smeller, László
2015-01-01
Proteins are essential players in the vast majority of molecular level life processes. Since their structure is in most cases substantial for their correct function, study of their structural changes attracted great interest in the past decades. The three dimensional structure of proteins is influenced by several factors including temperature, pH, presence of chaotropic and cosmotropic agents, or presence of denaturants. Although pressure is an equally important thermodynamic parameter as temperature, pressure studies are considerably less frequent in the literature, probably due to the technical difficulties associated to the pressure studies. Although the first steps in the high-pressure protein study have been done 100 years ago with Bridgman's ground breaking work, the field was silent until the modern spectroscopic techniques allowed the characterization of the protein structural changes, while the protein was under pressure. Recently a number of proteins were studied under pressure, and complete pressure-temperature phase diagrams were determined for several of them. This review summarizes the thermodynamic background of the typical elliptic p-T phase diagram, its limitations and the possible reasons for deviations of the experimental diagrams from the theoretical one. Finally we show some examples of experimentally determined pressure-temperature phase diagrams.
International Nuclear Information System (INIS)
Fraser, D.G.; Refson, K.
1992-01-01
The molecular dynamics calculations reported above give calculated P-V-T properties for H 2 O up to 1500 K and 100 GPa, which agree remarkably well with the available experimental data. We also observe the phase transition to a crystalline, orientationally disordered cubic ice structure. No account was taken of molecular flexibility in these calculations nor of potential dissociation at high pressures as suggested by Hamman (1981). However, we note that the closest next-nearest-neighbour O-H approach remains significantly greater than the TIP4P fixed O-H bond length within the water molecule for all pressures studied. The equation of state proposed here should be useful for estimating the properties of H 2 O at up to 1500 K and 100 G Pa (1 Mbar) and is much easier to use in practice than modified Redlich Kwong equations. Extension of these methods to the studies of other fluids and of fluid mixtures at high temperatures and pressures will require good potential models for the species involved, and this is likely to involve a combination of good ab initio work and semiempirical modelling. Once developed, these models should allow robust predictions of thermodynamic properties beyond the range of the experimental data on the basis of fundamental molecular information
PRETTA：A COMPUTER PROGRAM FOR PWR PRESSURIZER’S TRANSIENT THERMODYNAMICS
Institute of Scientific and Technical Information of China (English)
阿谢德; 徐济鋆
2001-01-01
A computer program PRETTA “Pressurizer Transient Thermodynamics Analysis” was developed for the prediction of pressurizer under transient conditions. It is based on the solution of the conservation laws of heat and mass applied to the three separate and non equilibrium thermodynamic regions. In the program all of the important thermal-hydraulics phenomena occurring in the pressurizer: stratification of the hot water and incoming cold water, bulk flashing and condensation, wall condensation, and interfacial heat and mass transfer have been considered. The bubble rising and rain-out models are developed to describe bulk flashing and condensation, respectively. To obtain the wall condensation rate, a one-dimensional heat conduction equation is solved by the pivoting method. The presented computer program will predict the pressure-time behavior of a PWR pressurizer during a variety of transients. The results obtained from the proposed mathematical model are in good agreement with available data on the CHASHMA nuclear power plant's pressurizer performance.
Kinetic and thermodynamic analysis of ultra-high pressure and heat ...
African Journals Online (AJOL)
Agriculture/Synergetic Innovation Center of Food Safety and Nutrition, Nanjing ... Purpose: To undertake comparative kinetic and thermodynamic analyses of the interaction of bovine ..... efficacy evaluation of anti-cancer drugs in apoptosis.
An open-source thermodynamic software library
DEFF Research Database (Denmark)
Ritschel, Tobias Kasper Skovborg; Gaspar, Jozsef; Capolei, Andrea
This is a technical report which accompanies the article ”An open-source thermodynamic software library” which describes an efficient Matlab and C implementation for evaluation of thermodynamic properties. In this technical report we present the model equations, that are also presented in the paper......, together with a full set of first and second order derivatives with respect to temperature and pressure, and in cases where applicable, also with respect to mole numbers. The library is based on parameters and correlations from the DIPPR database and the Peng-Robinson and the Soave-Redlich-Kwong equations...
Recommended vapor pressure and thermophysical data for ferrocene
Czech Academy of Sciences Publication Activity Database
Fulem, Michal; Růžička, K.; Červinka, C.; Rocha, M.A.A.; Santos, L.M.N.B.F.; Berg, R.F.
2013-01-01
Roč. 57, FEB (2013), 530-540 ISSN 0021-9614 Institutional support: RVO:68378271 Keywords : ferrocene * vapor pressure * heat capacity * ideal gas thermodynamic properties * sublimation enthalpy * recommended vapor pressure equation Subject RIV: BJ - Thermodynamics Impact factor: 2.423, year: 2013
Improved thermodynamics of SU(2) gauge theory
Energy Technology Data Exchange (ETDEWEB)
Giudice, Pietro [University of Muenster, Institute for Theoretical Physics, Muenster (Germany); Piemonte, Stefano [University of Regensburg, Institute for Theoretical Physics, Regensburg (Germany)
2017-12-15
In this work we present the results of our investigation of the thermodynamics of SU(2) gauge theory. We employ a Symanzik improved action to reduce strongly the discretisations effects, and we use the scaling relations to take into account the finite volume effects close to the critical temperature. We determine the β-function for this particular theory and we use it in the determination of different thermodynamic observables. Finally we compare our results with previous work where only the standard Wilson action was considered. We confirm the relevance of using the improved action to access easily the correct continuum thermodynamics of the theory. (orig.)
Thermodynamic study of selected monoterpenes II
Czech Academy of Sciences Publication Activity Database
Štejfa, V.; Fulem, Michal; Růžička, K.; Červinka, C.
2014-01-01
Roč. 79, Dec (2014), 272-279 ISSN 0021-9614 Institutional support: RVO:68378271 Keywords : monoterpenes * vapor pressure * heat capacity * ideal - gas thermodynamic properties * vaporization and sublimation enthalpy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.679, year: 2014
Thermodynamic study of selected monoterpenes III
Czech Academy of Sciences Publication Activity Database
Štejfa, V.; Fulem, Michal; Růžička, K.; Červinka, C.
2014-01-01
Roč. 79, Dec (2014), 280-289 ISSN 0021-9614 Institutional support: RVO:68378271 Keywords : monoterpenes * vapor pressure * heat capacity * ideal - gas thermodynamic properties * vaporization and sublimation enthalpy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.679, year: 2014
Molecular thermodynamics using fluctuation solution theory
DEFF Research Database (Denmark)
Ellegaard, Martin Dela
. The framework relates thermodynamic variables to molecular pair correlation functions of liquid mixtures. In this thesis, application of the framework is illustrated using two approaches: 1. Solubilities of solid solutes in mixed solvent systems are determined from fluctuation solution theory application......Properties of chemicals and their mutual phase equilibria are critical variables in process design. Reliable estimates of relevant equilibrium properties, from thermodynamic models, can form the basis of good decision making in the development phase of a process design, especially when access...... to relevant experimental data is limited. This thesis addresses the issue of generating and using simple thermodynamic models within a rigorous statistical mechanical framework, the so-called fluctuation solution theory, from which relations connecting properties and phase equilibria can be obtained...
Dynamism or Disorder at High Pressures?
Angel, R. J.; Bismayer, U.; Marshall, W. G.
2002-12-01
Phase transitions in minerals at elevated temperatures typically involve dynamics as a natural consequence of the increase in thermal energy available to the system. Classic examples include quartz, cristobalite, and carbonates in which the high-temperature, high symmetry phase is dynamically disordered. This disorder has important thermodynamic consequences, including displacement and curvature of phase boundaries (e.g. calcite-aragonite). In other minerals such as clinopyroxenes and anorthite feldspar, the dynamic behaviour is restricted to the neighbourhood of the phase transition. The fundamental question is whether increasing pressure generally suppresses such dynamic behaviour (as in anorthite; Angel, 1988), or not. In the latter case it must be included in thermodynamic models of high-pressure phase equilibria and seismological modelling of the mantle; the potential dynamics and softening in stishovite may provide the critical observational constraint on the presence or otherwise of free silica in the lower mantle. We have continued to use the lead phosphate as a prototype ferroelastic in which to understand dynamic behaviour, simply because its dynamics and transition behaviour is far better characterised than any mineral. Furthermore, the phase transition is at a pressure where experimental difficulties do not dominate the experimental results. Our previous neutron diffraction study (Angel et al., 2001) revealed that some disorder, either dynamic or static, is retained in the high-symmetry, high-pressure phase just above the phase transition. New neutron diffraction data on the pure material now suggests that this disorder slowly decreases with increasing pressure until at twice the transition pressure it is ordered. Further data for doped material provides insights into the nature of this disorder. Angel (1988) Amer. Mineral. 73:1114. Angel et al (2001) J PhysC 13: 5353.
Consistent thermodynamic properties of lipids systems
DEFF Research Database (Denmark)
Cunico, Larissa; Ceriani, Roberta; Sarup, Bent
different pressures, with azeotrope behavior observed. Available thermodynamic consistency tests for TPx data were applied before performing parameter regressions for Wilson, NRTL, UNIQUAC and original UNIFAC models. The relevance of enlarging experimental databank of lipids systems data in order to improve......Physical and thermodynamic properties of pure components and their mixtures are the basic requirement for process design, simulation, and optimization. In the case of lipids, our previous works[1-3] have indicated a lack of experimental data for pure components and also for their mixtures...... the performance of predictive thermodynamic models was confirmed in this work by analyzing the calculated values of original UNIFAC model. For solid-liquid equilibrium (SLE) data, new consistency tests have been developed [2]. Some of the developed tests were based in the quality tests proposed for VLE data...
Thermodynamic and Process Modelling of Gas Hydrate Systems in CO2 Capture Processes
DEFF Research Database (Denmark)
Herslund, Peter Jørgensen
A novel gas separation technique based on gas hydrate formation (solid precipitation) is investigated by means of thermodynamic modeling and experimental investigations. This process has previously been proposed for application in post-combustion carbon dioxide capture from power station flue gases...... formation may be performed at pressures of approximately 20 MPa and temperatures below 280 K. Thermodynamic promoters are needed, to reduce the pressure requirement of the process, thereby making it competitive to existing capture technologies. A literature study is presented focusing mainly...... on thermodynamic gas hydrate promotion by hydrate formers stabilising the classical gas clathrate hydrate structures (sI, sII and sH) at low to moderate pressures. Much literature is available on this subject. Both experimental and theoretical studies presented in the literature have pointed out cyclopentane...
Method of core thermodynamic reliability determination in pressurized water reactors
Energy Technology Data Exchange (ETDEWEB)
Ackermann, G.; Horche, W. (Ingenieurhochschule Zittau (German Democratic Republic). Sektion Kraftwerksanlagenbau und Energieumwandlung)
1983-01-01
A statistical model appropriate to determine the thermodynamic reliability and the power-limiting parameter of PWR cores is described for cases of accidental transients. The model is compared with the hot channel model hitherto applied.
Laminar forced convective heat transfer to near-critical water in a tube
International Nuclear Information System (INIS)
Lee, Sang Ho
2003-01-01
Numerical modeling is carried out to investigate forced convective heat transfer to near-critical water in developing laminar flow through a circular tube. Due to large variations of thermo-physical properties such as density, specific heat, viscosity, and thermal conductivity near thermodynamic critical point, heat transfer characteristics show quite different behavior compared with pure forced convection. With flow acceleration along the tube unusual behavior of heat transfer coefficient and friction factor occurs when the fluid enthalpy passes through pseudocritical point of pressure in the tube. There is also a transition behavior from liquid-like phase to gas-like phase in the developing region. Numerical results with constant heat flux boundary conditions are obtained for reduced pressures from 1.09 to 1.99. Graphical results for velocity, temperature, and heat transfer coefficient with Stanton number are presented and analyzed
Modeling the thermodynamics of QCD
Energy Technology Data Exchange (ETDEWEB)
Hell, Thomas
2010-07-26
Strongly interacting (QCD) matter is expected to exhibit a multifaceted phase structure: a hadron gas at low temperatures, a quark-gluon plasma at very high temperatures, nuclear matter in the low-temperature and high-density region, color superconductors at asymptotically high densities. Most of the conjectured phases cannot yet be scrutinized by experiments. Much of the present picture - particularly concerning the intermediate temperature and density area of the phase diagram of QCD matter - is based on model calculations. Further insights come from Lattice-QCD computations. The present thesis elaborates a nonlocal covariant extension of the Nambu and Jona-Lasinio (NJL) model with built-in constraints from the running coupling of QCD at high-momentum and instanton physics at low-momentum scales. We present this model for two and three quark flavors (in the latter case paying particular attention to the axial anomaly). At finite temperatures and densities, gluon dynamics is incorporated through a gluonic background field, expressed in terms of the Polyakov loop (P). The thermodynamics of this nonlocal PNJL model accounts for both chiral and deconfinement transitions. We obtain results in mean-field approximation and beyond, including additional pionic and kaonic contributions to the chiral condensate, the pressure and other thermodynamic quantities. Finally, the nonlocal PNJL model is applied to the finite-density region of the QCD phase diagram; for three quark flavors we investigate, in particular, the dependence of the critical point appearing in the models on the axial anomaly. The thesis closes with a derivation of the nonlocal PNJL model from first principles of QCD. (orig.)
Method of core thermodynamic reliability determination in pressurized water reactors
International Nuclear Information System (INIS)
Ackermann, G.; Horche, W.
1983-01-01
A statistical model appropriate to determine the thermodynamic reliability and the power-limiting parameter of PWR cores is described for cases of accidental transients. The model is compared with the hot channel model hitherto applied. (author)
Two-phase flow models in unbounded two-phase critical flows
International Nuclear Information System (INIS)
Celata, G.P.; Cumo, M.; Farello, G.E.
1985-01-01
With reference to a Loss-of-Coolant Accident in Light Water Reactors, an analysis of the unbounded two-phase critical flow (i.e. the issuing two-phase jet) has been accomplished. Considering jets external shape, obtained by means of photographic pictures; pressure profiles inside the jet, obtained by means of a movable ''Pitot;'' and jet phases distribution information, obtained by means of X-rays pictures; a characterization of the flow pattern in the unbounded region of a two-phase critical flow is given. Jets X-ray pictures show the existence of a central high density ''core'' gradually evaporating all around, which gives place to a characteristic ''dartflow'' the length of which depends on stagnation thermodynamic conditions
Statistical thermodynamics understanding the properties of macroscopic systems
Fai, Lukong Cornelius
2012-01-01
Basic Principles of Statistical PhysicsMicroscopic and Macroscopic Description of StatesBasic PostulatesGibbs Ergodic AssumptionGibbsian EnsemblesExperimental Basis of Statistical MechanicsDefinition of Expectation ValuesErgodic Principle and Expectation ValuesProperties of Distribution FunctionRelative Fluctuation of an Additive Macroscopic ParameterLiouville TheoremGibbs Microcanonical EnsembleMicrocanonical Distribution in Quantum MechanicsDensity MatrixDensity Matrix in Energy RepresentationEntropyThermodynamic FunctionsTemperatureAdiabatic ProcessesPressureThermodynamic IdentityLaws of Th
Thermodynamic analyses and optimization of a recompression N2O Brayton power cycle
International Nuclear Information System (INIS)
Sarkar, Jahar
2010-01-01
Thermodynamic analyses and simultaneous optimizations of cycle pressure ratio and flow split fraction to get maximum efficiency of N 2 O recompression Brayton cycle have been performed to study the effects of various operating conditions and component performances. The energetic as well as exergetic performance comparison with its counterpart recompression CO 2 cycle is presented as well. Optimization shows that the optimum minimum cycle pressure is close to pseudo-critical pressure for supercritical cycle, whereas saturation pressure corresponding to minimum cycle temperature for condensation cycle. Results show that the maximum thermal efficiency increases with decrease in minimum cycle temperature and increase in both maximum cycle pressure and temperature. Influence of turbine performance on cycle efficiency is more compared to that of compressors, HTR (high temperature recuperator) and LTR (low temperature recuperator). Comparison shows that N 2 O gives better thermal efficiency (maximum deviation of 1.2%) as well as second law efficiency compared to CO 2 for studied operating conditions. Component wise irreversibility distribution shows the similar trends for both working fluids. Present study reveals that N 2 O is a potential option for the recompression power cycle.
Second Law Of Thermodynamics Analysis Of Triple Cycle Power Plant
Directory of Open Access Journals (Sweden)
Matheus M. Dwinanto
2012-11-01
Full Text Available Triple cycle power plant with methane as a fuel has been analyzed on the basis of second law of thermodynamics.In this model, ideal Brayton cycle is selected as a topping cycle as it gives higher efficiency at lower pressure ratio comparedintercooler and reheat cycle. In trilple cycle the bottoming cycles are steam Rankine and organic Rankine cycle. Ammoniahas suitable working properties like critical temperature, boiling temperature, etc. Steam cycle consists of a deaerator andreheater. The bottoming ammonia cycle is a ideal Rankine cycle. Single pressure heat recovery steam and ammoniagenerators are selected for simplification of the analysis. The effects of pressure ratio and maximum temperature which aretaken as important parameters regarding the triple cycle are discussed on performance and exergetic losses. On the otherhand, the efficiency of the triple cycle can be raised, especially in the application of recovering low enthalpy content wasteheat. Therefore, by properly combining with a steam Rankine cycle, the ammonia Rankine cycle is expected to efficientlyutilize residual yet available energy to an optimal extent. The arrangement of multiple cycles is compared with combinedcycle having the same sink conditions. The parallel type of arrangement of bottoming cycle is selected due to increasedperformance.
Phosphorus Dimerization in Gallium Phosphide at High Pressure
Energy Technology Data Exchange (ETDEWEB)
Lavina, Barbara [High Pressure Science and Engineering Center, University of Nevada, Las Vegas, Nevada 89154, United States; Department of Physics and Astronomy, University of Nevada, Las Vegas, Nevada 89154, United States; Kim, Eunja [Department of Physics and Astronomy, University of Nevada, Las Vegas, Nevada 89154, United States; Cynn, Hyunchae [Lawrence Livermore National Laboratory, Livermore, California 94550, United States; Weck, Philippe F. [Sandia National Laboratories, Albuquerque, New Mexico 87185, United States; Seaborg, Kelly [High Pressure Science and Engineering Center, University of Nevada, Las Vegas, Nevada 89154, United States; Department of Physics and Astronomy, University of Nevada, Las Vegas, Nevada 89154, United States; Siska, Emily [High Pressure Science and Engineering Center, University of Nevada, Las Vegas, Nevada 89154, United States; Meng, Yue [HPCAT, Carnegie Institution of Washington, Argonne, Illinois 60439, United States; Evans, William [Lawrence Livermore National Laboratory, Livermore, California 94550, United States
2018-02-09
Using combined experimental and computational approaches, we show that at 43 GPa and 1300 K gallium phosphide adopts the super-Cmcm structure, here indicated with its Pearson notation oS24. First-principles enthalpy calculations demonstrate that this structure is more thermodynamically stable above ~20 GPa than previously proposed polymorphs. Here, in contrast to other polymorphs, the oS24 phase shows a strong bonding differentiation and distorted fivefold coordination geometries of both P atoms. The shortest bond of the phase is a single covalent P–P bond measuring 2.171(11) Å at synthesis pressure. Phosphorus dimerization in GaP sheds light on the nature of the super-Cmcm phase and provides critical new insights into the high-pressure polymorphism of octet semiconductors. Bond directionality and anisotropy explain the relatively low symmetry of this high-pressure phase.
Directory of Open Access Journals (Sweden)
J. M. Dick
2006-01-01
Full Text Available Thermodynamic calculations can be used to quantify environmental constraints on the speciation of proteins, such as the pH and temperature dependence of ionization state, and the relative chemical stabilities of proteins in different biogeochemical settings. These calculations depend in part on values of the standard molal Gibbs energies of proteins and their ionization reactions as a function of temperature and pressure. Because these values are not generally available, we calculated values of the standard molal thermodynamic properties at 25°C and 1 bar as well as the revised Helgeson-Kirkham-Flowers equations of state parameters of neutral and charged zwitterionic reference model compounds including aqueous amino acids, polypeptides, and unfolded proteins. The experimental calorimetric and volumetric data for these species taken from the literature were combined with group additivity algorithms to calculate the properties and parameters of neutral and ionized sidechain and backbone groups in unfolded proteins. The resulting set of group contributions enables the calculation of the standard molal Gibbs energy, enthalpy, entropy, isobaric heat capacity, volume, and isothermal compressibility of unfolded proteins in a range of proton ionization states to temperatures and pressures exceeding 100°C and 1000 bar. This approach provides a useful frame of reference for thermodynamic studies of protein folding and complexation reactions. It can also be used to assign provisional values of the net charge and Gibbs energy of ionized proteins as a function of temperature and pH. Using these values, an Eh-pH diagram for a reaction representing the speciation of extracellular proteins from Pyrococcus furiosus and Bacillus subtilis was generated. The predicted predominance limits of these proteins correspond with the different electrochemical conditions of hydrothermal vents and soils. More comprehensive calculations of this kind may reveal pervasive
The Donnan equilibrium: I. On the thermodynamic foundation of the Donnan equation of state
International Nuclear Information System (INIS)
Philipse, A; Vrij, A
2011-01-01
The thermodynamic equilibrium between charged colloids and an electrolyte reservoir is named after Frederic Donnan who first published on it one century ago (Donnan 1911 Z. Electrochem. 17 572). One of the intriguing features of the Donnan equilibrium is the ensuing osmotic equation of state which is a nonlinear one, even when both colloids and ions obey Van 't Hoff's ideal osmotic pressure law. The Donnan equation of state, nevertheless, is internally consistent; we demonstrate it to be a rigorous consequence of the phenomenological thermodynamics of a neutral bulk suspension equilibrating with an infinite salt reservoir. Our proof is based on an exact thermodynamic relation between osmotic pressure and salt adsorption which, when applied to ideal ions, does indeed entail the Donnan equation of state. Our derivation also shows that, contrary to what is often assumed, the Donnan equilibrium does not require ideality of the colloids: the Donnan model merely evaluates the osmotic pressure of homogeneously distributed ions, in excess of the pressure exerted by an arbitrary reference fluid of uncharged colloids. We also conclude that results from the phenomenological Donnan model coincide with predictions from statistical thermodynamics in the limit of weakly charged, point-like colloids.
Magmas near the critical degassing pressure drive volcanic unrest towards a critical state
Chiodini, Giovanni; Paonita, Antonio; Aiuppa, Alessandro; Costa, Antonio; Caliro, Stefano; De Martino, Prospero; Acocella, Valerio; Vandemeulebrouck, Jean
2016-01-01
During the reawaking of a volcano, magmas migrating through the shallow crust have to pass through hydrothermal fluids and rocks. The resulting magma–hydrothermal interactions are still poorly understood, which impairs the ability to interpret volcano monitoring signals and perform hazard assessments. Here we use the results of physical and volatile saturation models to demonstrate that magmatic volatiles released by decompressing magmas at a critical degassing pressure (CDP) can drive volcanic unrest towards a critical state. We show that, at the CDP, the abrupt and voluminous release of H2O-rich magmatic gases can heat hydrothermal fluids and rocks, triggering an accelerating deformation that can ultimately culminate in rock failure and eruption. We propose that magma could be approaching the CDP at Campi Flegrei, a volcano in the metropolitan area of Naples, one of the most densely inhabited areas in the world, and where accelerating deformation and heating are currently being observed. PMID:27996976
Thermodynamics of geothermal fluids
Energy Technology Data Exchange (ETDEWEB)
Rogers, P.S.Z.
1981-03-01
A model to predict the thermodynamic properties of geothermal brines, based on a minimum amount of experimental data on a few key systems, is tested. Volumetric properties of aqueous sodium chloride, taken from the literature, are represented by a parametric equation over the range 0 to 300{sup 0}C and 1 bar to 1 kbar. Density measurements at 20 bar needed to complete the volumetric description also are presented. The pressure dependence of activity and thermal properties, derived from the volumetric equation, can be used to complete an equation of state for sodium chloride solutions. A flow calorimeter, used to obtain heat capacity data at high temperatures and pressures, is described. Heat capacity measurements, from 30 to 200{sup 0}C and 1 bar to 200 bar, are used to derive values for the activity coefficient and other thermodynamic properties of sodium sulfate solutions as a function of temperature. Literature data on the solubility of gypsum in mixed electrolyte solutions have been used to evaluate model parameters for calculating gypsum solubility in seawater and natural brines. Predictions of strontium and barium sulfate solubility in seawater also are given.
Alternative thermodynamic cycle for the Stirling machine
Romanelli, Alejandro
2017-12-01
We develop an alternative thermodynamic cycle for the Stirling machine, where the polytropic process plays a central role. Analytical expressions for pressure and temperatures of the working gas are obtained as a function of the volume and the parameter that characterizes the polytropic process. This approach achieves closer agreement with the experimental pressure-volume diagram and can be adapted to any type of Stirling engine.
Critical behavior of the dielectric constant in asymmetric fluids.
Bertrand, C E; Sengers, J V; Anisimov, M A
2011-12-08
By applying a thermodynamic theory that incorporates the concept of complete scaling, we derive the asymptotic temperature dependence of the critical behavior of the dielectric constant above the critical temperature along the critical isochore and below the critical temperature along the coexistence curve. The amplitudes of the singular terms in the temperature expansions are related to the changes of the critical temperature and the critical chemical potential upon the introduction of an electric field. The results of the thermodynamic theory are then compared with the critical behavior implied by the classical Clausius-Mossotti approximation. The Clausius-Mossotti approximation fails to account for any singular temperature dependence of the dielectric constant above the critical temperature. Below the critical temperature it produces an apparent asymmetric critical behavior with singular terms similar to those implied by the thermodynamic theory, but with significantly different coefficients. We conclude that the Clausius-Mossotti approximation only can account for the observed asymptotic critical behavior of the dielectric constant when the dependence of the critical temperature on the electric field is negligibly small. © 2011 American Chemical Society
Thermodynamic and structural characteristics of cement minerals at elevated temperature
International Nuclear Information System (INIS)
Bruton, C.J.; Meike, A.; Viani, B.E.; Martin, S.; Phillips, B.L.
1994-05-01
We have instituted an experimental and including program designed to elucidate the structural and thermodynamic response of cement minerals to elevated temperature. Components of the program involve: (a) synthesis of hydrated Ca-silicates; (b) structural analysis of cement phases induced by heating and dehydration/rehydration; (c) mechanistic and thermodynamic descriptions of the hydration/dehydration behavior of hydrated Ca-silicates as a function of temperature, pressure and relative humidity; (d) study of naturally occurring hydrated Ca-silicates; and (e) measurements of thermodynamic data for hydrated Ca-silicates
International Nuclear Information System (INIS)
1966-01-01
Knowledge of the thermodynamics of nuclear materials is vital to the design of reactor fuels and moderating and cooling systems, in fact all facets of nuclear plant operation that involve mixtures of, or contact between, two or more elements in single- or multi-phase systems. The steep thermal gradients and the high temperatures involved in nuclear technology pose special problems for engineers and thermodynamicists, who have found that extrapolation of low-temperature data to high temperatures very often proves invalid. For this reason, standard thermodynamic techniques such as calorimetry and EMF-methods have been extended into high-temperature regions. Since the Agency's last conference on this subject, also held in Vienna (Thermodynamics of Nuclear Materials, 1962), there have been notable advances in calorimetry performed at temperatures greater than 1000°C, and in the use of EMF cells with solid electrolytes operated at similar temperatures. Significant advances have also been made in measuring diffusion parameters at the higher temperatures. An important field covered in this Symposium was the correlation of such atomic transport data with thermodynamic data, a prerequisite if the nuclear engineer is to incorporate diffusion results into his normal process- assessment techniques. Finally the Symposium suggested the requirements for good critical tables. The mere compiling of such data is no longer sufficient; the compiler must have free access to all the data of a particular experiment, he must have an intimate knowledge of experimental work in this field and he must weight every figure quoted in the light of his experience. As a step in this direction, the Agency has called on the services of many well-known experts and is preparing a number of monographs giving critical assessments of thermodynamic data and phase-diagrams for many of the elements of interest in reactor design. Most of the countries engaged in research in thermodynamics were represented at
Energy Technology Data Exchange (ETDEWEB)
NONE
1966-02-15
Knowledge of the thermodynamics of nuclear materials is vital to the design of reactor fuels and moderating and cooling systems, in fact all facets of nuclear plant operation that involve mixtures of, or contact between, two or more elements in single- or multi-phase systems. The steep thermal gradients and the high temperatures involved in nuclear technology pose special problems for engineers and thermodynamicists, who have found that extrapolation of low-temperature data to high temperatures very often proves invalid. For this reason, standard thermodynamic techniques such as calorimetry and EMF-methods have been extended into high-temperature regions. Since the Agency's last conference on this subject, also held in Vienna (Thermodynamics of Nuclear Materials, 1962), there have been notable advances in calorimetry performed at temperatures greater than 1000 Degree-Sign C, and in the use of EMF cells with solid electrolytes operated at similar temperatures. Significant advances have also been made in measuring diffusion parameters at the higher temperatures. An important field covered in this Symposium was the correlation of such atomic transport data with thermodynamic data, a prerequisite if the nuclear engineer is to incorporate diffusion results into his normal process- assessment techniques. Finally the Symposium suggested the requirements for good critical tables. The mere compiling of such data is no longer sufficient; the compiler must have free access to all the data of a particular experiment, he must have an intimate knowledge of experimental work in this field and he must weight every figure quoted in the light of his experience. As a step in this direction, the Agency has called on the services of many well-known experts and is preparing a number of monographs giving critical assessments of thermodynamic data and phase-diagrams for many of the elements of interest in reactor design. Most of the countries engaged in research in thermodynamics were
Energy Technology Data Exchange (ETDEWEB)
NONE
1966-01-15
Knowledge of the thermodynamics of nuclear materials is vital to the design of reactor fuels and moderating and cooling systems, in fact all facets of nuclear plant operation that involve mixtures of, or contact between, two or more elements in single- or multi-phase systems. The steep thermal gradients and the high temperatures involved in nuclear technology pose special problems for engineers and thermodynamicists, who have found that extrapolation of low-temperature data to high temperatures very often proves invalid. For this reason, standard thermodynamic techniques such as calorimetry and EMF-methods have been extended into high-temperature regions. Since the Agency's last conference on this subject, also held in Vienna (Thermodynamics of Nuclear Materials, 1962), there have been notable advances in calorimetry performed at temperatures greater than 1000 Degree-Sign C, and in the use of EMF cells with solid electrolytes operated at similar temperatures. Significant advances have also been made in measuring diffusion parameters at the higher temperatures. An important field covered in this Symposium was the correlation of such atomic transport data with thermodynamic data, a prerequisite if the nuclear engineer is to incorporate diffusion results into his normal process- assessment techniques. Finally the Symposium suggested the requirements for good critical tables. The mere compiling of such data is no longer sufficient; the compiler must have free access to all the data of a particular experiment, he must have an intimate knowledge of experimental work in this field and he must weight every figure quoted in the light of his experience. As a step in this direction, the Agency has called on the services of many well-known experts and is preparing a number of monographs giving critical assessments of thermodynamic data and phase-diagrams for many of the elements of interest in reactor design. Most of the countries engaged in research in thermodynamics were
Thermodynamic structure of the marine atmosphere over the region ...
Indian Academy of Sciences (India)
R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22
course of observations the ship moved from an open ... Marine boundary layer; thermodynamic structure; saturation point; Bay of Bengal Monsoon Experiment; .... when the low-pressure area is close to the ship the pressure is low and as the system moves away, the .... over oceanic regions to characterize the differences.
Thermodynamic assessment of the Cu–Fe–Ni system
International Nuclear Information System (INIS)
Dreval, Liya A.; Turchanin, Mikhail A.; Agraval, Pavel G.
2014-01-01
Highlights: • The thermodynamic description of the Cu–Fe–Ni system has been updated. • The new experimental data have been used to refine thermodynamic model of the system. • The four-sublattice model has been adopted to predict the equilibria involving the ordered L1 2 phase. • A significant improvement in comparison with the previous assessments has been achieved. • The liquidus and solidus projections have been presented. -- Abstract: The thermodynamic description of the Cu–Fe–Ni system has been updated considering the newly available experimental data, as well as compatibility of the present modeling with those used for the Cu and Fe systems. All of the experimental data available in the literature have been critically reviewed, and the inconsistent information has been excluded. The thermodynamic parameters have been evaluated in order to properly describe the thermodynamic properties of the liquid phase and miscibility gap in the solid state. A significant improvement in comparison with the previous thermodynamic descriptions has been achieved. Additionally, for the ordered L1 2 phase the four-sublattice model has been adopted to predict the ternary phase equilibria involving this phase. A set of thermodynamic parameters for the phases is given
Directory of Open Access Journals (Sweden)
Hye-sung Na
2018-01-01
Full Text Available In the 21st century, there is an increasing need for high-capacity, high-efficiency, and environmentally friendly power generation systems. The environmentally friendly integrated gasification combined-cycle (IGCC technology has received particular attention. IGCC pressure vessels require a high-temperature strength and creep strength exceeding those of existing pressure vessels because the operating temperature of the reactor is increased for improved capacity and efficiency. Therefore, high-pressure vessels with thicker walls than those in existing pressure vessels (≤200 mm must be designed. The primary focus of this research is the development of an IGCC pressure vessel with a fully bainitic structure in the middle portion of the 300 mm thick Cr-Mo steel walls. For this purpose, the effects of the alloy content and cooling rates on the ferrite precipitation and phase transformation behaviors were investigated using JMatPro modeling and thermodynamic calculation; the results were then optimized. Candidate alloys from the simulated results were tested experimentally.
Ab-initio study of phase stability, elastic and thermodynamic properties of AlY alloy under pressure
Energy Technology Data Exchange (ETDEWEB)
Zhou, Dawei [College of Physics and Electronic Engineering, Nanyang Normal University, Nanyang 473061 (China); Su, Taichao [Institute of Materials Science and Engineering, Henan Polytechnic University, Jiaozuo 454000 (China); Song, Haizhen; Lu, Cheng; Zhong, Zhiguo; Lu, Zhiwen [College of Physics and Electronic Engineering, Nanyang Normal University, Nanyang 473061 (China); Pu, Chunying, E-mail: puchunying@126.com [College of Physics and Electronic Engineering, Nanyang Normal University, Nanyang 473061 (China)
2015-11-05
Using the particle swarm optimization algorithm combined with first-principles methods, we explore the diagram of AlY alloy up to 250 GPa. It is found that AlDy phase, rather than the experimentally observed B2 phase, is the most stable structure at 0 K and 0–20 GPa. However, our results show that B2 phase can exist as a stable phase at 20–27.6 GPa. At higher pressure, four new high-pressure phases with Cmcm-I, Cmcm-II, I4/mmm and P4/nmm structure are identified for the first time. The hardness, elastic and thermodynamic properties of the newly found phases are investigated and compared with B2 phase. The calculated hardness of AlDy, Cmcm-I, Cmcm-II, I4/mmm and P4/nmm phases is in the range of 7–9 GPa, higher than that of B2 phase. In addition, it is found that AlDy phase is a brittle material at 0 GPa, which changes to a ductile material above 12 GPa. Except for AlDy phase, all the other AlY compounds exhibit completely ductile behavior under pressure. Compared with the other phases, B2 phase is found to have the best ductility and the largest elastic anisotropy over the whole pressure investigated. Moreover, all AlY intermetallics exhibit a nearly elastic isotropy in compressibility but a comparatively large elastic anisotropy in shear. The structural stability, electronic structure, bulk and shear modulus, Debye temperature as well as sound velocities of AlY alloy under pressure are also deeply discussed. - Graphical abstract: Pressure-induced phase transition of AlY alloy up to 250 GPa. - Highlights: • The diagram of AlY alloy was explored and four new stable phases were predicted. • B2 phase shows the largest ductility and elastic anisotropy among AlY alloys. • All AlY alloys exhibit ductile behavior except for AlDy phase under pressure. • All AlY alloys show strong isotropy in compressibility and anisotropy in shear.
Czech Academy of Sciences Publication Activity Database
Štejfa, V.; Fulem, Michal; Růžička, K.; Matějka, P.
2015-01-01
Roč. 402, Sep (2015), 18-29 ISSN 0378-3812 Institutional support: RVO:68378271 Keywords : alcohols * vapor pressure * heat capacity * ideal - gas thermodynamic properties * vaporization enthalpy Subject RIV: BJ - Thermodynamics Impact factor: 1.846, year: 2015
A study in cosmology and causal thermodynamics
International Nuclear Information System (INIS)
Oliveira, H.P. de.
1986-01-01
The especial relativity of thermodynamic theories for reversible and irreversible processes in continuous medium is studied. The formalism referring to equilibrium and non-equilibrium configurations, and theories which includes the presence of gravitational fields are discussed. The nebular model in contraction with dissipative processes identified by heat flux and volumetric viscosity is thermodymically analysed. This model is presented by a plane conformal metric. The temperature, pressure, entropy and entropy production within thermodynamic formalism which adopts the hypothesis of local equilibrium, is calculated. The same analysis is carried out considering a causal thermodynamics, which establishes a local entropy of non-equilibrium. Possible homogeneous and isotropic cosmological models, considering the new phenomenological equation for volumetric viscosity deriving from cause thermodynamics are investigated. The found out models have plane spatial section (K=0) and some ones do not have singularities. The energy conditions are verified and the entropy production for physically reasobable models are calculated. (M.C.K.) [pt
International Nuclear Information System (INIS)
Bonasera, A.; Latora, V.; Ploszajczak, M.
1996-07-01
The maximal Lyapunov exponents (LE) are calculated, starting from concepts of hydrodynamics. Analytical expressions for the LE can be found in ergodic limit by using results of the classical thermodynamics for a Boltzmann gas and for systems undergoing a second order phase transition. A recipe is given to measure LE in systems which might have a critical behavior, such as a Bose-Einstein condensation or a transition to a quark-gluon plasma. (author)
Critical heat flux with subcooled boiling of water at low pressure
International Nuclear Information System (INIS)
Chen Yuzhou; Zhou Runbin; Hao Laomi; Chen Haiyan
1997-01-01
The critical heat flux experiment has been performed in round tubes of 10 and 16 mm in diameter with different heating length, covering the range of pressure 1.5-16.7 bar, velocity 1.4-15.4 m/s and exit subcooling 30-136 K. The experimental data and empirical correlations are presented. Based on the results an evaluation of some correlations and 1995 CHF look-up table is made. For the conditions tested the effect of diameter on the critical heat flux is found to be related to the liquid velocity. (author)
Effect of pressure on critical heat flux for water in an internally heated annulus
International Nuclear Information System (INIS)
Mishima, Kaichiro; Hibiki, Takashi; Nishihara, Hideaki
2004-01-01
It was pointed out earlier that existing CHF correlations based upon data for annuli at high pressures did not reproduce CHF very well at the atmospheric pressure. It appears to be necessary to investigate CHF at intermediate pressures to interpret the apparent discrepancy between CHFs at high and low pressures. In view of this an experiment was performed to obtain more information on CHF at intermediate pressures and the effect of pressure was discussed in the present study. It was revealed from this study that the effect of pressure on the CHF in the range from 0.1 to 1 MPa could be explained by the annular flow boundary and the critical quality. (author)
Thermodynamic properties of aqueous hydroxyurea solutions
International Nuclear Information System (INIS)
Kumar, Shekhar; Sinha, Pranay Kumar; Kamachi Mudali, U.; Natarajan, R.
2011-01-01
Hydroxyurea is a novel reductant for uranium-plutonium separation in PUREX process. Little information on its thermophysical properties is available in published literature. In this work, its contributions to aqueous density, apparent molal volume, vapour pressure and thermodynamic water activity values, derived from in-house experiments, are reported. (author)
International Nuclear Information System (INIS)
Bai, Guangyue; Wang, Yujie; Ding, Yanhong; Zhuo, Kelei; Wang, Jianji; Bastos, Margarida
2016-01-01
Highlights: • ITC provided thermodynamic characterization of self-association of oppositely charged gemini/SDS surfactants. • Phase transitions and corresponding enthalpies were obtained by ITC. • The transitions reflect a change in morphology, supported by Cryo-TEM images. • Conductivity and ITC results show very good agreement. • An asymmetric distribution of surfactants in the aggregates is supported by results. - Abstract: The thermodynamics and phase behavior of mixtures of cationic gemini surfactant decanediyl-α,ω-bis(dodecyldimethylammonium bromide) (12-10-12) and sodium dodecylsulfate (SDS) were studied in the dilute SDS-rich region. The enthalpy of interaction between both surfactant monomers before the critical micelle concentration for the mixture (cmc_m_i_x) was determined by isothermal titration calorimetry (ITC). After the cmc_m_i_x, ITC results exhibited a first process associated with a large endothermic enthalpy change followed by a second one with a very small exothermic enthalpy change. In the same regions, the conductivity curves show an increase in slope after the break, followed by a plateau region, respectively for the two processes. The combined results from the various methodologies used lead us to propose that the first process reflects the formation of non-spherical micelles and the second one the vesicle formation. The area per catanionic complex was obtained through surface pressure measurements, leading to an apparent packing parameter ⩾1. The observed behavior may be rationalized on the basis of the hypothesis that both surfactants distribute asymmetrically in the vesicle bilayers and unevenly in the non-spherical micelle. In order to get structural information Cryo-TEM experiments were performed, which provided images that support this interpretation. From all the information gathered a phase diagram was mapped, including three one-phase regions of spherical micelles, non-spherical micelles and vesicles.
Directory of Open Access Journals (Sweden)
Boudia Keltouma
2015-12-01
Full Text Available Structural, elastic, electronic and thermodynamic properties of ternary cubic filled skutterudite compound were calculated. We have computed the elastic modulus and its pressure dependence. From the elastic parameter behavior, it is inferred that this compound is elastically stable and ductile in nature. Through the quasi-harmonic Debye model, in which phononic effects are considered, the effect of pressure P (0 to 50 GPa and temperature T (0 to 3000 °C on the lattice constant, elastic parameters, bulk modulus B, heat capacity, thermal expansion coefficient α, internal energy U, entropy S, Debye temperature θD, Helmholtz free energy A, and Gibbs free energy G are investigated.
Yan, Hai-Yan; Zhang, Mei-Guang; Huang, Duo-Hui; Wei, Qun
2013-04-01
The first-principles study on the elastic properties, elastic anisotropy and thermodynamic properties of the orthorhombic OsB4 is reported using density functional theory method with the ultrasoft pseudopotential scheme in the frame of the generalized gradient approximation. The calculated equilibrium parameters are in good agreement with the available theoretical data. A complete elastic tensor and crystal anisotropies of the ultra-incompressible OsB4 are determined in the pressure range of 0-50 GPa. By the elastic stability criteria, it is predicted that the orthorhombic OsB4 is stable below 50 GPa. By using the quasi-harmonic Debye model, the heat capacity, the coefficient of thermal expansion, and the Grüneisen parameter of OsB4 are also successfully obtained in the present work.
Thermodynamic properties of solid deuterium in premelting region
International Nuclear Information System (INIS)
Udovichenko, B.G.; Esel'son, V.B.; Manzhelij, V.G.
1984-01-01
Thermal expansion and isothermal compressibility of solid normal deuterium are measured near the melting line under pressures up to 500 atm. The earlier measurement method is improved to operate in a wider range of working pressures. The effects are discussed which are produced by zero trranslational oscillations in the thermodynamic properties of deuterium. The change in the molar volume in the range from T=0 to the melting temperature is considered as a quantum characteristic of the crystal. The molar volumes of solid deuterium observed at the melting line at moderate P are compared and specified. At P=O and T=0 the molar volume of o-D 2 is found to be V 00 =(20.03+-0.07) cm 3 /mole which follows from the thermodynamic experiment
International Nuclear Information System (INIS)
Hamm, L.L.; Van Brunt, V.
1982-08-01
A comparison of implicit Runge-Kutta and orthogonal collocation methods is made for the numerical solution to the ordinary differential equation which describes the high-pressure vapor-liquid equilibria of a binary system. The systems of interest are limited to binary solubility systems where one of the components is supercritical and exists as a noncondensable gas in the pure state. Of the two methods - implicit Runge-Kuta and orthogonal collocation - this paper attempts to present some preliminary but not necessarily conclusive results that the implicit Runge-Kutta method is superior for the solution to the ordinary differential equation utilized in the thermodynamic consistency testing of binary solubility systems. Due to the extreme nonlinearity of thermodynamic properties in the region near the critical locus, an extended cubic spline fitting technique is devised for correlating the P-x data. The least-squares criterion is employed in smoothing the experimental data. Even though the derivation is presented specifically for the correlation of P-x data, the technique could easily be applied to any thermodynamic data by changing the endpoint requirements. The volumetric behavior of the systems must be given or predicted in order to perform thermodynamic consistency tests. A general procedure is developed for predicting the volumetric behavior required and some indication as to the expected limit of accuracy is given
Skin necrosis in a critically ill patient due to a blood pressure cuff
Directory of Open Access Journals (Sweden)
Devbhandari Mohan
2006-01-01
Full Text Available The non-invasive method of blood pressure measurement is regarded as a safe procedure and the reports of any serious complications are rare. We report a unique case of extensive skin necrosis due to an intermittently inflating blood pressure cuff in a 65-year-old critically ill lady following a third time redo mitral valve surgery. A brief review of the literature on complications associated with noninvasive method of measurement of blood pressure is presented along with possible mechanisms of skin injury and ways to avoid it.
Thermodynamic properties of 1-phenylnaphthalene and 2-phenylnaphthalene
International Nuclear Information System (INIS)
Chirico, Robert D.; Steele, William V.; Kazakov, Andrei F.
2014-01-01
Highlights: • Heat capacities, vapor pressures, enthalpies of combustion, and densities were measured for 1-phenylnaphthalene (1-PhN). • Heat capacities and vapor pressures were measured for 2-phenylnaphthalene (2-PhN). • Independent ideal-gas entropies derived with the calorimetric results and statistical methods are in accord for 1-PhN. • 2-PhN showed glassy-crystal behavior in the solid state, and an entropy deficit is demonstrated. - Abstract: Measurements leading to the calculation of thermodynamic properties in the ideal-gas state for 1-phenylnaphthalene (Chemical Abstracts registry number [605-02-7]) and 2-phenylnaphthalene (Chemical Abstracts registry number [612-94-2]) are reported. Experimental methods for 1-phenylnaphthalene were adiabatic heat-capacity calorimetry, differential scanning calorimetry, inclined-piston manometry, comparative ebulliometry, vibrating-tube densitometry, and combustion calorimetry. For 2-phenylnaphthalene, the experimental methods were adiabatic heat-capacity calorimetry, differential scanning calorimetry, and comparative ebulliometry. Critical properties were estimated for both compounds. Molar thermodynamic functions (enthalpies, entropies, and Gibbs free energies) for the condensed and ideal-gas states were derived from the experimental studies at selected temperatures. Statistical calculations were performed based on molecular geometry optimization and vibrational frequencies calculated at the B3LYP/6-31+G(d, p) and B3LYP/cc-pVTZ levels of theory. Ideal-gas entropies derived with two the independent methods are shown to be in good accord for 1-phenylnaphthalene, but significant differences are apparent for 2-phenylnaphthalene. These differences are likely due to a disorder of unknown type in the crystals of 2-phenylnaphthalene at low temperatures, as evidenced by the presence of a glass-like transition in the measured heat capacities for the solid state. All experimental results are compared with property values
Thermodynamic assessment of the Sn–Sr system supported by first-principles calculations
International Nuclear Information System (INIS)
Zhao, Jingrui; Du, Yong; Zhang, Lijun; Wang, Aijun; Zhou, Liangcai; Zhao, Dongdong; Liang, Jianlie
2012-01-01
Highlights: ► All the literature data of Sn–Sr system is critically reviewed. ► First-principles calculation of enthalpy of formation is carried out for each compound. ► Thermodynamic parameters for Sn–Sr system are obtained by CALPHAD method. ► A hybrid approach of CALPHAD and first-principles calculations is recommended. - Abstract: A hybrid approach of CALPHAD and first-principles calculations was employed to perform a thermodynamic modeling of the Sn–Sr system. The experimental phase diagram and thermodynamic data available in the literature were critically reviewed. The enthalpies of formation for the 6 stoichiometric compounds (i.e. Sr 2 Sn, Sr 5 Sn 3 , SrSn, Sr 3 Sn 5 , SrSn 3 and SrSn 4 ) at 0 K were computed by means of first-principles calculations. These data were used as the experimental values in the optimization module PARROT in the subsequent CALPHAD assessment to provide thermodynamic parameters with sound physical meaning. A set of self-consistent thermodynamic parameters was finally obtained by considering reliable literature data and the first-principles computed results. Comprehensive comparisons between the calculated and measured quantities indicate that all the reliable experimental information can be satisfactorily accounted for by the present thermodynamic description.
International Nuclear Information System (INIS)
Hwang, Jeong Ui; Jang, Jong Jae; Jee, Jong Gi
1987-01-01
The contents of this book are thermodynamics on the law of thermodynamics, classical thermodynamics and molecule thermodynamics, basics of molecule thermodynamics, molecule and assembly partition function, molecule partition function, classical molecule partition function, thermodynamics function for ideal assembly in fixed system, thermodynamics function for ideal assembly in running system, Maxwell-Boltzmann's law of distribution, chemical equilibrium like calculation of equilibrium constant and theory of absolute reaction rate.
Computation of thermodynamic equilibrium in systems under stress
Vrijmoed, Johannes C.; Podladchikov, Yuri Y.
2016-04-01
Metamorphic reactions may be partly controlled by the local stress distribution as suggested by observations of phase assemblages around garnet inclusions related to an amphibolite shear zone in granulite of the Bergen Arcs in Norway. A particular example presented in fig. 14 of Mukai et al. [1] is discussed here. A garnet crystal embedded in a plagioclase matrix is replaced on the left side by a high pressure intergrowth of kyanite and quartz and on the right side by chlorite-amphibole. This texture apparently represents disequilibrium. In this case, the minerals adapt to the low pressure ambient conditions only where fluids were present. Alternatively, here we compute that this particular low pressure and high pressure assemblage around a stressed rigid inclusion such as garnet can coexist in equilibrium. To do the computations we developed the Thermolab software package. The core of the software package consists of Matlab functions that generate Gibbs energy of minerals and melts from the Holland and Powell database [2] and aqueous species from the SUPCRT92 database [3]. Most up to date solid solutions are included in a general formulation. The user provides a Matlab script to do the desired calculations using the core functions. Gibbs energy of all minerals, solutions and species are benchmarked versus THERMOCALC, PerpleX [4] and SUPCRT92 and are reproduced within round off computer error. Multi-component phase diagrams have been calculated using Gibbs minimization to benchmark with THERMOCALC and Perple_X. The Matlab script to compute equilibrium in a stressed system needs only two modifications of the standard phase diagram script. Firstly, Gibbs energy of phases considered in the calculation is generated for multiple values of thermodynamic pressure. Secondly, for the Gibbs minimization the proportion of the system at each particular thermodynamic pressure needs to be constrained. The user decides which part of the stress tensor is input as thermodynamic
Thermodynamic modeling to analyse composition of carbonaceous ...
Indian Academy of Sciences (India)
Equilibrium thermodynamic analysis has been applied to the low-pressure MOCVD process using manganese acetylacetonate as the precursor. ``CVD phase stability diagrams” have been constructed separately for the processes carried out in argon and oxygen ambient, depicting the compositions of the resulting films as ...
Non-equilibrium thermodynamics of radiation-induced processes in solids
International Nuclear Information System (INIS)
Yurov, V.M.; Eshchanov, A.N.; Kuketaev, A.T.; Sidorenya, Yu.S.
2005-01-01
In the paper an item about a defect system response in solids on external action (temperature, pressure, light, etc.) from the point of view of non-equilibrium statistical thermodynamics is considered
Critical heat flux on micro-structured zircaloy surfaces for flow boiling of water at low pressures
International Nuclear Information System (INIS)
Haas, C.; Miassoedov, A.; Schulenberg, T.; Wetzel, T.
2012-01-01
The influence of surface structure on critical heat flux for flow boiling of water was investigated for Zircaloy tubes in a vertical annular test section. The objectives were to find suitable surface modification processes for Zircaloy tubes and to test their critical heat flux performance in comparison to the smooth tube. Surface structures with micro-channels, porous layer, oxidized layer, and elevations in micro- and nano-scale were produced on a section of a Zircaloy cladding tube. These modified tubes were tested in an internally heated vertical annulus with a heated length of 326 mm and an inner and outer diameter of 9.5 and 18 mm. The experiments were performed with mass fluxes of 250 and 400 kg/(m 2 s), outlet pressures between 120 and 300 kPa, and constant inlet subcooling enthalpy of 167 kJ/kg. Only a small influence of modified surface structures on critical heat flux was observed for the pressure of 120 kPa in the present test section geometry. However, with increasing pressure the critical heat flux could increase up to 29% using the surface structured tubes with micro-channels, porous and oxidized layers. Capillary effects and increased nucleation site density are assumed to improve the critical heat flux performance. (authors)
International Nuclear Information System (INIS)
Hendi, S.H.; Eslam Panah, B.; Panahiyan, S.
2017-01-01
Violation of Lorentz invariancy in the high energy quantum gravity motivates one to consider an energy dependent spacetime with massive deformation of standard general relativity. In this paper, we take into account an energy dependent metric in the context of a massive gravity model to obtain exact solutions. We investigate the geometry of black hole solutions and also calculate the conserved and thermodynamic quantities, which are fully reproduced by the analysis performed with the standard techniques. After examining the validity of the first law of thermodynamics, we conduct a study regarding the effects of different parameters on thermal stability of the solutions. In addition, we employ the relation between cosmological constant and thermodynamical pressure to study the possibility of phase transition. Interestingly, we will show that for the specific configuration considered in this paper, van der Waals like behavior is observed for different topology. In other words, for flat and hyperbolic horizons, similar to spherical horizon, a second order phase transition and van der Waals like behavior are observed. Furthermore, we use geometrical method to construct phase space and study phase transition and bound points for these black holes. Finally, we obtain critical values in extended phase space through the use of a new method.
Directory of Open Access Journals (Sweden)
S.H. Hendi
2017-06-01
Full Text Available Violation of Lorentz invariancy in the high energy quantum gravity motivates one to consider an energy dependent spacetime with massive deformation of standard general relativity. In this paper, we take into account an energy dependent metric in the context of a massive gravity model to obtain exact solutions. We investigate the geometry of black hole solutions and also calculate the conserved and thermodynamic quantities, which are fully reproduced by the analysis performed with the standard techniques. After examining the validity of the first law of thermodynamics, we conduct a study regarding the effects of different parameters on thermal stability of the solutions. In addition, we employ the relation between cosmological constant and thermodynamical pressure to study the possibility of phase transition. Interestingly, we will show that for the specific configuration considered in this paper, van der Waals like behavior is observed for different topology. In other words, for flat and hyperbolic horizons, similar to spherical horizon, a second order phase transition and van der Waals like behavior are observed. Furthermore, we use geometrical method to construct phase space and study phase transition and bound points for these black holes. Finally, we obtain critical values in extended phase space through the use of a new method.
Tables of thermodynamic properties of helium magnet coolant
International Nuclear Information System (INIS)
McAshan, M.
1992-07-01
The most complete treatment of the thermodynamic properties of helium at the present time is the monograph by McCarty: ''Thermodynamic Properties of Helium 4 from 2 to 1500 K at Pressures to 10 8 Pa'', Robert D. McCarty, Journal of Physical and Chemical Reference Data, Vol. 2, page 923--1040 (1973). In this work the complete range of data on helium is examined and the P-V-T surface is described by an equation of state consisting of three functions P(r,T) covering different regions together with rules for making the transition from one region to another. From this thermodynamic compilation together with correlations of the transport properties of helium was published the well-known NBS Technical Note: ''Thermophysical Properties of Helium 4 from 2 to 1500 K with pressures to 1000 Atmospheres'', Robert D. McCarty, US Department of Commerce, National Bureau of Standards Technical Note 631 (1972). This is the standard reference for helium cryogenics. The NBS 631 tables cover a wide range of temperature and pressure, and as a consequence, the number of points tabulated in the region of the single phase coolant for the SSC magnets are relatively few. The present work sets out to cover the range of interest in more detail in a way that is consistent with NBS 631. This new table is essentially identical to the older one and can be used as an auxiliary to it
Energy Technology Data Exchange (ETDEWEB)
Schaube, F.; Koch, L. [German Aerospace Center, Institute of Technical Thermodynamics, Pfaffenwaldring 38-40, 70569 Stuttgart (Germany); Woerner, A., E-mail: antje.woerner@dlr.de [German Aerospace Center, Institute of Technical Thermodynamics, Pfaffenwaldring 38-40, 70569 Stuttgart (Germany); Mueller-Steinhagen, H. [German Aerospace Center, Institute of Technical Thermodynamics, Pfaffenwaldring 38-40, 70569 Stuttgart (Germany)
2012-06-20
Highlights: Black-Right-Pointing-Pointer Investigation of the thermodynamic equilibrium and reaction enthalpy of 'Ca(OH){sub 2} {r_reversible} CaO + H{sub 2}O'. Black-Right-Pointing-Pointer Investigation of the reaction kinetics of the dehydration of Ca(OH){sub 2} at partial pressures up to 956 mbar. Black-Right-Pointing-Pointer Investigation of the reaction kinetics of the rehydration of Ca(OH){sub 2} at partial pressures up to 956 mbar. - Abstract: Heat storage technologies are used to improve energy efficiency of power plants and recovery of process heat. Storing thermal energy by reversible thermo-chemical reactions offers a promising option for high storage capacities especially at high temperatures. Due to its low material cost, the use of the reversible reaction Ca(OH){sub 2} Rightwards-Harpoon-Over-Leftwards-Harpoon CaO + H{sub 2}O has been proposed. This paper reports on the physical properties such as heat capacity, thermodynamic equilibrium, reaction enthalpy and kinetics. To achieve high reaction temperatures, high H{sub 2}O partial pressures are required. Therefore the cycling stability is confirmed for H{sub 2}O partial pressures up to 95.6 kPa and the dehydration and hydration kinetics are studied. Quantitative data are collected and expressions are derived which are in good agreement with the presented measurements. At 1 bar H{sub 2}O partial pressure the expected equilibrium temperature is 505 Degree-Sign C and the reaction enthalpy is 104.4 kJ/mol.
Black, Joyce; Berke, Christine; Urzendowski, Gail
2012-01-01
The primary objective of this study was to compare facility-acquired pressure ulcer incidence and progression of pressure ulcers present on admission in critically ill patients, using 2 different support surfaces. We completed a comparison cohort study in a surgical intensive care unit (ICU). The study setting was a 12-bed cardiovascular ICU in a university-based hospital in the Midwestern United States. The sample comprised 52 critically ill patients; 31 were placed on low air loss weight-based pressure redistribution-microclimate management system beds and 21 were placed on integrated powered air pressure redistribution beds. Prior to the start of the study, 5 low airloss beds were placed in open rooms in the cardiovascular surgical ICU. Inclusion criteria were anticipated ICU stay of 3 days, and patients did not receive a speciality bed for pulmonary or wound issues. Initial assessment of the patients included risk assessment and prior events that would increase risk for pressure ulcer development such as extended time in operating room, along with skin assessment for existing pressure ulcers. Subjects in both groups had ongoing skin assessment every 3 to 4 days and a subjective evaluation of heel elevation and turning or repositioning by the researcher. Data were collected until the subjects were dismissed from the ICU. Patients admitted to the unit were assigned to open rooms following the usual protocols. The mean length of stay was 7.0 days, with an 8.1-day length of stay for subjects on "low air loss with microclimate management" beds (LAL-MCM) and 6.6 days on the integrated power pressure air redistribution (IP-AR) beds (P = NS). The incidence of pressure ulcers on the buttocks, sacrum, or coccyx was 0% (0/31) on the low air loss bed and 18% (4/21) on the IP-AR bed (P = .046). Five subjects had 6 pressure ulcers on admission. Two pressure ulcers on 2 patients worsened on the integrated power air redistribution beds, which required specialty bed rental
The interactions between IC engine thermodynamics and knock
International Nuclear Information System (INIS)
Caton, Jerald A.
2017-01-01
Highlights: • Importance of engine thermodynamics regarding knock was quantified. • Effects of compression ratio, engine speed and EGR on knock was reported. • Retarding combustion to avoid knock resulted in decreases of efficiency. - Abstract: The development of high efficiency spark-ignition internal combustion engines is often constrained by the occurrence of knock. Knock may result in engine damage, lower performance, and lower efficiency. The options for preventing knock often involve lower compression ratios, lower boost, retarded spark timing, and other design choices that are detrimental to engine performance and efficiency. Since knock is largely a function of the thermodynamic state of the unburned zone, the occurrence of knock is expected to be a strong function of the engine thermodynamics. The purpose of the current work is to couple a simple knock model with a comprehensive engine cycle simulation to determine the interactions between the engine thermodynamics and knock. This work has explored the effects of engine parameters such as compression ratio (4–12), engine speed (500–2500 rpm), inlet pressure (50–100 kPa), exhaust gas recirculation (0–25%), combustion duration and heat transfer on knock. In each case, the occurrence of knock is connected to the cylinder pressures and the gas temperatures of the unburned zone. For example for a compression ratio of 12, to avoid knock the brake thermal efficiency decreased from 36.5% to 34% due to retarding the combustion.
Amend, Jan P.; Plyasunov, Andrey V.
2001-11-01
Experimental thermodynamic data for aqueous organic compounds can be combined with the revised Helgeson-Kirkham-Flowers (HKF) equations of state to generate parameters that can be used to estimate standard molal properties as functions of temperature and pressure. In this study, we regressed thermodynamic data for aqueous carbohydrates at temperatures up to 393 K reported in the literature to permit the calculation of the apparent standard molal Gibbs free energies and enthalpies of formation (ΔGo and ΔHo, respectively) and the standard molal entropies (S2o), heat capacities (CP,2o), and volumes (V2o) to 423 K and several hundred MPa of aqueous C5 aldoses (ribose, arabinose, xylose, lyxose) and C5 ketoses (ribulose, xylulose) as well as C6 aldoses (glucose, mannose, galactose) and C6 ketoses (fructose, sorbose). Values of ΔGo for these 11 aqueous carbohydrates are given as a function of temperature at the saturated water vapor pressure (PSAT) and at 50 MPa. Values of ΔGo for aqueous glucose are then combined with those of other aqueous organic and inorganic compounds to calculate values of the standard molal Gibbs free energies of 13 fermentation and respiration reactions (ΔGro) known or likely to be carried out by thermophilic microorganisms. Finally, values of the overall Gibbs free energies of these reactions (ΔGr) are calculated at the temperature, pressure, and chemical composition that obtain in the hydrothermal fluids of Vulcano Island, southern Italy, a site that is widely known for its tremendous diversity of organisms able to live at high temperatures. At likely activities of aqueous glucose, it is shown that thermophiles in the hot springs of Vulcano at 373 K and ∼0.1 MPa can gain between 400 and 3000 kJ per mole of glucose fermented or respired.
Critical behavior and phase transition of dilaton black holes with nonlinear electrodynamics
Energy Technology Data Exchange (ETDEWEB)
Dayyani, Z.; Dehghani, M.H.; Hajkhalili, S. [Shiraz University, Physics Department and Biruni Observatory, College of Sciences, Shiraz (Iran, Islamic Republic of); Sheykhi, A. [Shiraz University, Physics Department and Biruni Observatory, College of Sciences, Shiraz (Iran, Islamic Republic of); Research Institute for Astronomy and Astrophysics of Maragha (RIAAM), Maragha (Iran, Islamic Republic of)
2018-02-15
In this paper, we take into account the dilaton black hole solutions of Einstein gravity in the presence of logarithmic and exponential forms of nonlinear electrodynamics. First of all, we consider the cosmological constant and nonlinear parameter as thermodynamic quantities which can vary. We obtain thermodynamic quantities of the system such as pressure, temperature and Gibbs free energy in an extended phase space. We complete the analogy of the nonlinear dilaton black holes with the Van der Waals liquid-gas system. We work in the canonical ensemble and hence we treat the charge of the black hole as an external fixed parameter. Moreover, we calculate the critical values of temperature, volume and pressure and show that they depend on the dilaton coupling constant as well as on the nonlinear parameter. We also investigate the critical exponents and find that they are universal and independent of the dilaton and nonlinear parameters, which is an expected result. Finally, we explore the phase transition of nonlinear dilaton black holes by studying the Gibbs free energy of the system. We find that in the case of T > T{sub c}, we have no phase transition. When T = T{sub c}, the system admits a second-order phase transition, while for T = T{sub f} < T{sub c} the system experiences a first-order transition. Interestingly, for T{sub f} < T < T{sub c} we observe a zeroth-order phase transition in the presence of a dilaton field. This novel zeroth-order phase transition occurs due to a finite jump in the Gibbs free energy which is generated by the dilaton-electromagnetic coupling constant, α, for a certain range of pressure. (orig.)
Vrabec, Jadran; Kedia, Gaurav Kumar; Buchhauser, Ulrich; Meyer-Pittroff, Roland; Hasse, Hans
2009-02-01
For the design and optimization of CO 2 recovery from alcoholic fermentation processes by distillation, models for vapor-liquid equilibria (VLE) are needed. Two such thermodynamic models, the Peng-Robinson equation of state (EOS) and a model based on Henry's law constants, are proposed for the ternary mixture N 2 + O 2 + CO 2. Pure substance parameters of the Peng-Robinson EOS are taken from the literature, whereas the binary parameters of the Van der Waals one-fluid mixing rule are adjusted to experimental binary VLE data. The Peng-Robinson EOS describes both binary and ternary experimental data well, except at high pressures approaching the critical region. A molecular model is validated by simulation using binary and ternary experimental VLE data. On the basis of this model, the Henry's law constants of N 2 and O 2 in CO 2 are predicted by molecular simulation. An easy-to-use thermodynamic model, based on those Henry's law constants, is developed to reliably describe the VLE in the CO 2-rich region.
Skeletal muscle oxygen pressure fields in artificially ventilated, critically ill patients
International Nuclear Information System (INIS)
Lund, N.; Jorfeldt, L.; Lewis, D.H.; Oedman, S.
1980-01-01
The MDO (Mehrdraht Dostmund Oberflaeche) oxygen electrode was used in a study of skeletal muscle oxygen pressure fields, presented as histograms, in critically ill patients artificially ventilated with gas mixtures of different oxygen concentrations. The histograms were compared with forearm blood flow measurements performed with strain gauge plethysmography. Local blood flow and permeability-surface area product (PS) were also studied by the simultaneous clearances of 133 xenon and 51 Cr-EDTA. The histogram distribution type was normal, i.e. approximately Gaussian, at arterial oxygen pressure levels between 10 and 18 kPa. At arterial oxygen pressures outside this range the histogram distribution types were abnormal, i.e. they showed a non-symmetrical distribution of oxygen pressure values, but their mean was approximately the same as in the normal histogram. However, there were significantly higher tissue oxygen pressure mean values in the patients (3.43 kPa) than in a group of healthy human volunteers (2.25 kPa). Mean forearm blood flow and the clearances of 133 xenon and 51 Cr-EDTA showed marked variations during the measurements both intraindividually and interindividually. Mean forearm blood flow and mean clearances of 133 xenon showed opposite trends compared with arterial oxygen pressures. Mean clearances of 51 Cr-EDTA and mean PS showed minor variations at the different arterial oxygen pressure levels. (author)
Critical Phenomena in Higher Curvature Charged AdS Black Holes
Directory of Open Access Journals (Sweden)
Arindam Lala
2013-01-01
Full Text Available In this paper, we have studied the critical phenomena in higher curvature charged AdS black holes. We have considered Lovelock-Born-Infeld-AdS black hole as an example. The thermodynamics of the black hole have been studied which reveals the onset of a higher-order phase transition in the black hole in the canonical ensemble (fixed charge ensemble framework. We have analytically derived the critical exponents associated with these thermodynamic quantities. We find that our results fit well with the thermodynamic scaling laws and consistent with the mean field theory approximation. The suggestive values of the other two critical exponents associated with the correlation function and correlation length on the critical surface have been derived.
Energy Technology Data Exchange (ETDEWEB)
Anversa, Jonas [Departamento de Física, Universidade Federal de Santa Maria, 97105-900, Santa Maria, RS (Brazil); Escola de Engenharia Civil, Faculdade Meridional, 99070-220, Passo Fundo, RS (Brazil); Chakraborty, Sudip, E-mail: sudiphys@gmail.com [Condensed Matter Theory Group, Department of Physics and Astronomy, Box 516, Uppsala University, S-75120 Uppsala (Sweden); Piquini, Paulo [Departamento de Física, Universidade Federal de Santa Maria, 97105-900, Santa Maria, RS (Brazil); Ahuja, Rajeev [Condensed Matter Theory Group, Department of Physics and Astronomy, Box 516, Uppsala University, S-75120 Uppsala (Sweden); Applied Materials Physics, Department of Materials and Engineering, Royal Institute of Technology (KTH), S-100 44 Stockholm (Sweden)
2016-05-23
In this letter, we are reporting the change of superconducting critical temperature in Sb{sub 2}Se{sub 3} topological insulator under the influence of an external hydrostatic pressure based on first principles electronic structure calculations coupled with Migdal–Eliashberg model. Experimentally, it was shown previously that Sb{sub 2}Se{sub 3} was undergoing through a transition to a superconducting phase when subjected to a compressive pressure. Our results show that the critical temperature increases up to 6.15 K under the pressure unto 40 GPa and, subsequently, drops down until 70 GPa. Throughout this pressure range, the system is preserving the initial Pnma symmetry without any structural transformation. Our results suggest that the possible relevant mechanism behind the superconductivity in Sb{sub 2}Se{sub 3} is primarily the electron–phonon coupling.
Gases and carbon in metals - thermodynamics, kinetics, and properties. Pt. 11
International Nuclear Information System (INIS)
Jehn, H.; Speck, H.; Fromm, E.; Hoerz, G.
1980-01-01
This issue is part of a series of data on Gases and Carbon in Metals which supplements the data compilation in the book Gase and Kohlenstoff in Metallen (Gases and Carbon in Metals), edited by E.Fromm and E.Gebhardt, Springer-Verlag, Berlin 1976. The present survey includes results from papers published after the copy deadline and recommends critically selected data. Furthermore it comprises a bibliography of relevant literature. For each element the information is given in two parts. In a first section data are listed and in a second section the relevant literature is compiled. For each element, firstly data on binary systems are presented, starting with hydrogen and followed by carbon, nitrogen, oxygen, and rare gases. Within one metal-metalloid system the data are listed under topics such as solubility, solubility limit, dissociation pressure of compounds, vapour pressure of volatile oxides, thermodynamic data, diffusion, transport parameters (effective valence, heat of transport), permeation of gases through metals, gas absorption and gas desorption kinetics, compound formation kinetics, precipitation kinetics, and property changes. (orig./GE)
The thermodynamic properties of normal liquid helium 3
Modarres, M.; Moshfegh, H. R.
2009-09-01
The thermodynamic properties of normal liquid helium 3 are calculated by using the lowest order constrained variational (LOCV) method. The Landau Fermi liquid model and Fermi-Dirac distribution function are considered as our statistical model for the uncorrelated quantum fluid picture and the Lennard-Jones and Aziz potentials are used in our truncated cluster expansion (LOCV) to calculate the correlated energy. The single particle energy is treated variationally through an effective mass. The free energy, pressure, entropy, chemical potential and liquid phase diagram as well as the helium 3 specific heat are evaluated, discussed and compared with the corresponding available experimental data. It is found that the critical temperature for the existence of the pure gas phase is about 4.90 K (4.45 K), which is higher than the experimental prediction of 3.3 K, and the helium 3 flashing temperature is around 0.61 K (0.50 K) for the Lennard-Jones (Aziz) potential.
Existence of a critical point in the phase diagram of the ideal relativistic neutral Bose gas
International Nuclear Information System (INIS)
Park, Jeong-Hyuck; Kim, Sang-Woo
2011-01-01
We explore the phase transitions of the ideal relativistic neutral Bose gas confined in a cubic box, without assuming the thermodynamic limit nor continuous approximation. While the corresponding non-relativistic canonical partition function is essentially a one-variable function depending on a particular combination of temperature and volume, the relativistic canonical partition function is genuinely a two-variable function of them. Based on an exact expression for the canonical partition function, we performed numerical computations for up to 10 5 particles. We report that if the number of particles is equal to or greater than a critical value, which amounts to 7616, the ideal relativistic neutral Bose gas features a spinodal curve with a critical point. This enables us to depict the phase diagram of the ideal Bose gas. The consequent phase transition is first order below the critical pressure or second order at the critical pressure. The exponents corresponding to the singularities are 1/2 and 2/3, respectively. We also verify the recently observed 'Widom line' in the supercritical region.
International Nuclear Information System (INIS)
Yılmaz, İbrahim Halil; Saka, Kenan; Kaynakli, Omer
2016-01-01
One of the parameters affecting the COP of the absorption system can be considered as the thermal balance between the high pressure condenser (HPC) and the low pressure generator (LPG) since heat rejected from the HPC is utilized as an energy source by the LPG. Condensation of the water vapor in the HPC depends on the heat removal via the LPG. This circumstance is significant for making an appropriate design and a controllable system with high performance in practical applications. For this reason, a thermodynamic analysis for the HPC of a double effect series flow water/lithium bromide absorption refrigeration system was emphasized in this study. A simulation was developed to investigate the energy transfer between the HPC and LPG. The results show that the proper designation of the HPC temperature improves the COP and ECOP due its significant impact, and its value necessarily has to be higher than the outlet temperature of the LPG based on the operating scheme. Furthermore, the COP and ECOP of the absorption system can be raised in the range of 9.72–35.09% in case of 2 °C-temperature increment in the HPC under the described conditions to be applied. - Highlights: • Thermal balance in HPC/LPG unit of a double effect absorption system was studied. • A simulation program was developed and its outputs were validated. • A parametric study was conducted for a wide range of component temperatures. • Proper designation of the HPC temperature improves the COP and ECOP. • The system performance raised 9.72–35.09% by controlling the HPC temperature.
Hinz, Jos?; Mansur, Ashham; Hanekop, Gerd G.; Weyland, Andreas; Popov, Aron F.; Schmitto, Jan D.; Gr?ne, Frank F. G.; Bauer, Martin; Kazmaier, Stephan
2016-01-01
The effects of isoflurane on the determinants of blood flow during Coronary Artery Bypass Graft (CABG) surgery are not completely understood. This study characterized the influence of isoflurane on the diastolic Pressure-Flow (P-F) relationship and Critical Occlusion Pressure (COP) during CABG surgery. Twenty patients undergoing CABG surgery were studied. Patients were assigned to an isoflurane or control group. Hemodynamic and flow measurements during CABG surgery were perf...
Krause, Tom; Anders, Jennifer; von Renteln-Kruse, Wolfgang
2005-10-01
The association between urinary incontinence and pressure sores is put down to various causes. Most frequently urinary wet and following maceration of the skin are mentioned. However, it is possible that urinary incontinence is only an indicator for other risk factors or a measure of the need for care without any causal relation to pressure sores. There are hardly any controlled or randomised studies; this lack of scientific evidence is problematic. Based on a case-control-study including data of 200 patients as well as on the existing models of explanation, the following study tries to examine critically the connections between pressure sores and urinary incontinence. Out of the patients in our study population 97.5 percent were incontinent. Different categories of the risk factor urinary incontinence and different dichotomisations have led to different statistical results. Statements concerning the connection between urinary incontinence and pressure sores have to be interpreted critically. The dependence of urinary incontinence on other risk factors such as patients' need for care or compliance suggests that the causal connection to pressure sores be not reduced to the influence of wetness. We advise to research connections between urinary incontinence and pressure sores in a methodologically appropriate setting.
de Oliveira, Mário J
2017-01-01
This textbook provides an exposition of equilibrium thermodynamics and its applications to several areas of physics with particular attention to phase transitions and critical phenomena. The applications include several areas of condensed matter physics and include also a chapter on thermochemistry. Phase transitions and critical phenomena are treated according to the modern development of the field, based on the ideas of universality and on the Widom scaling theory. For each topic, a mean-field or Landau theory is presented to describe qualitatively the phase transitions. These theories include the van der Waals theory of the liquid-vapor transition, the Hildebrand-Heitler theory of regular mixtures, the Griffiths-Landau theory for multicritical points in multicomponent systems, the Bragg-Williams theory of order-disorder in alloys, the Weiss theory of ferromagnetism, the Néel theory of antiferromagnetism, the Devonshire theory for ferroelectrics and Landau-de Gennes theory of liquid crystals. This new edit...
Pressure Ulcer Risk Evaluation in Critical Patients: Clinical and Social Characteristics.
de Azevedo Macena, Mônica Suêla; da Costa Silva, Rayanne Suely; Dias Fernandes, Maria Isabel Da Conceição; de Almeida Medeiros, Ana Beatriz; Batista Lúcio, Kadyjina Daiane; de Carvalho Lira, Ana Luisa Brandão
2017-01-01
Pressure ulcers increase hospital stays and treatment costs due to their complications. Therefore, recognizing factors that contribute to pressure ulcer risk are important to patient safety. To evaluate the association between the scores of the Waterlow, Braden, and Norton scales and clinical and social characteristics in critically ill patients. A cross-sectional study of 78 patients in an adult intensive care unit of a university hospital in Northeastern Brazil was conducted from July to December 2015. Data included social and clinical information and the risk factors of the Braden, Norton and Waterlow scales. Data were analysed by the descriptive and inferential statistics. Most of the participants were female, adults and elderly people with brown skin colour, low education levels and insufficient income. Most of them showed a high risk for developing pressure ulcers using the three evaluated scales. Age, smoking status, diabetes and hypertension were associated with scores on the Waterlow, Braden and Norton scales. Age, use of the tobacco, diabetes and hypertension were associated with the risk of pressure ulcers in ICU patients.
On the interfacial thermodynamics of nanoscale droplets and bubbles
Corti, David S.; Kerr, Karl J.; Torabi, Korosh
2011-07-01
We present a new self-consistent thermodynamic formalism for the interfacial properties of nanoscale embryos whose interiors do not exhibit bulklike behavior and are in complete equilibrium with the surrounding mother phase. In contrast to the standard Gibbsian analysis, whereby a bulk reference pressure based on the same temperature and chemical potentials of the mother phase is introduced, our approach naturally incorporates the normal pressure at the center of the embryo as an appropriate reference pressure. While the interfacial properties of small embryos that follow from the use of these two reference pressures are different, both methods yield by construction the same reversible work of embryo formation as well as consistency between their respective thermodynamic and mechanical routes to the surface tension. Hence, there is no a priori reason to select one method over another. Nevertheless, we argue, and demonstrate via a density-functional theory (with the local density approximation) analysis of embryo formation in the pure component Lennard-Jones fluid, that our new method generates more physically appealing trends. For example, within the new approach the surface tension at all locations of the dividing surface vanishes at the spinodal where the density profile spanning the embryo and mother phase becomes completely uniform (only the surface tension at the Gibbs surface of tension vanishes in the Gibbsian method at this same limit). Also, for bubbles, the location of the surface of tension now diverges at the spinodal, similar to the divergent behavior exhibited by the equimolar dividing surface (in the Gibbsian method, the location of the surface of tension vanishes instead). For droplets, the new method allows for the appearance of negative surface tensions (the Gibbsian method always yields positive tensions) when the normal pressures within the interior of the embryo become less than the bulk pressure of the surrounding vapor phase. Such a
D2O, Computation of Thermodynamic and Transport Properties of Heavy Water
International Nuclear Information System (INIS)
Durmayaz, Ahmet
2000-01-01
1 - Description of program or function: A computer program for the fast computation of the thermodynamic and transport properties of heavy water (D 2 O) at saturation, in subcooled liquid and superheated vapor states. Specific volume (or density), specific enthalpy, specific entropy, constant-pressure specific heat and temperature at saturation are calculated by a number of piecewise continuous approximation functions of (and their derivatives are calculated with respect to) pressure whereas pressure at saturation is calculated by a piecewise continuous approximation function of temperature for heavy water. Density in subcooled liquid state, specific volume in super-heated vapor state, specific enthalpy, specific entropy and constant-pressure specific heat in both of these states are calculated by some piecewise continuous approximation functions of pressure and temperature for heavy water. The correlations used in the calculation of these thermodynamic properties of heavy water were derived by fitting some appropriate curves to the data given in the steam tables by Hill et al (1981). The whole set of correlations and the approximation method used in their derivation are presented by Durmayaz (1997). Dynamic viscosity and thermal conductivity for heavy water are calculated as functions of temperature and density with the correlations given by Hill et al (1981), by Matsunaga and Nagashima (1983) and by Kestin et al (1984). Surface tension for heavy water is calculated as a function of temperature with the correlation given by Crabtree and Siman-Tov (1993). 2 - Methods: A group of pressure-enthalpy (P-h) pairs can be given in an input data file or assigned in the main program without knowing the state in which fluid takes place. In this case, first, the enthalpies at saturation corresponding to the given pressure are computed. Second, the state is determined by comparing the given enthalpy to the saturation enthalpies. Then, the properties are computed. Program D 2 O
International Nuclear Information System (INIS)
Brik, M.G.; Łach, P.; Karczewski, G.; Wojtowicz, T.; Kamińska, A.; Suchocki, A.
2013-01-01
Luminescence of CdTe quantum dots embedded in ZnTe is quenched at pressure of about 4.5 GPa in the high-pressure experiments. This pressure-induced quenching is attributed to the “zinc-blende–cinnabar” phase transition in CdTe, which was confirmed by the first-principles calculations. Theoretical analysis of the pressure at which the phase transition occurs for CdTe was performed using the CASTEP module of Materials Studio package with both generalized gradient approximation (GGA) and local density approximation (LDA). The calculated phase transition pressures are equal to about 4.4 GPa and 2.6 GPa, according to the GGA and LDA calculations, respectively, which is in a good agreement with the experimental value. Theoretically estimated value of the pressure coefficient of the band-gap luminescence in zinc-blende structure is in very good agreement with that recently measured in the QDs structures. The calculated Debye temperature, elastic constants and specific heat capacity for the zinc-blend structure agree well with the experimental data; the data for the cinnabar phase are reported here for the first time to the best of the authors' knowledge. - Highlights: • Quenching of luminescence of CdTe quantum dots embedded in ZnTe is theoretically explained. • The theoretical calculation of elastic and thermodynamic properties of CdTe by two types of ab-initio methods. • Theoretical calculations of some optical properties of CdTe under pressure in zinc-blende and cinnabar phases
International Nuclear Information System (INIS)
Dubacq, B.
2008-12-01
Phyllosilicates are important minerals in metamorphic petrology as well as in waste storage sites where clays are extensively used. Despite this fact, there is no thermodynamic model allowing to describe and to predict properly the behaviour of clay minerals (for example variation of volume with dehydration) and their phase relations with other minerals in metamorphic conditions. Inversely, the thermodynamic models of phengites are well constrained at high pressure and temperature but do not allow accurate thermo-barometric estimations at temperatures less than about 350 C. In this study, we propose two new thermodynamic models for smectites, illites, mixed-layers illites / smectites and phengites. With these models, it is possible to predict the composition of stable clays at low temperature and to estimate the pressure and temperature of crystallisation of di-octahedral aluminous phyllosilicates. These models take into consideration the hydration state of clay minerals as a function of pressure, temperature and water activity. The thermodynamic properties of solid solutions and hydrated mica-like end-members have been estimated in order to reproduce experimental results of i) clay dehydration, ii) nature of stable phases, iii) calorimetric measurements, as well as known (or estimated with independent methods) pressure-temperature conditions of crystallization of phyllosilicates analyses, from diagenesis conditions to ultra - high - pressure / temperature conditions. Phase diagrams have been computed with these models in simple systems. Conditions of crystallization of phyllosilicates have been estimated on many samples, including electron microprobe compositional maps. We investigated several approaches to estimate thermodynamic properties of minerals. All these methods revealed to be insufficiently accurate to estimate standard enthalpy of formation; calculated enthalpies of formation can not be directly used for thermo-barometric estimations. However, we
Directory of Open Access Journals (Sweden)
V. P. Kascheev
2009-01-01
Full Text Available The paper considers problems leading to erosion wear of flowing part of a mean pressure turbine cylinder operating beyond critical parameters. Explanation of erosion wear of flowing part of a mean pressure turbine cylinder which is proved in practice and recommendations for wear reduction are given in the paper
Chlorine international thermodynamic tables of the fluid state
Angus, S; de Reuck, K M
1985-01-01
Chlorine: International Thermodynamic Tables of the Fluid State-8 is a four-chapter book that covers available and estimated data on chlorine; estimation of the element's properties; the correlating equations for the element; and how the tabulated properties are calculated from chosen equation. The tables in this book give the volume, entropy, enthalpy, isobaric heat capacity, compression factor, fugacity/pressure ratio, Joule-Thomson coefficient, ratio of the heat capacities, and speed of sound as a function of pressure and temperature. Given in the tables as well are the pressure, entropy, i
Determination of Burst Pressure of API Steel Pipes using Stress Modified Critical Strain Model
International Nuclear Information System (INIS)
Alang, N A; Razak, N A; Sulaiman, A S
2012-01-01
This paper presents a technique which can be used to determine the burst pressure of defective steel pipes using non-linear finite element (FE) analysis. The technique uses stress modified critical strain (SMCS) failure criterion to study the effect of gouge defects on maximum working pressure of API X65 steel pipes. The procedures in determining the model parameters using 3-D, homogeneous isotropic elastic-plastic material model with large deformation finite element analyses from notched tensile bars were systematically discussed. The relationship between burst pressure and gouge depth was proposed. The burst pressure estimated then was compared to experimental data from the literature for validation showing overall good agreements.
Thermodynamic calculations of self- and hetero-diffusion parameters in germanium
International Nuclear Information System (INIS)
Saltas, V.; Vallianatos, F.
2015-01-01
In the present work, the diffusion coefficients of n- and p-type dopants (P, As, Sb, Al) and self-diffusion in crystalline germanium are calculated from the bulk elastic properties of the host material based on the cBΩ thermodynamic model. The calculated diffusion coefficients as a function of temperature and the activation enthalpies prove to be in full agreement with the reported experimental results. Additional point defect parameters such as activation entropy, activation volume and activation Gibbs free energy are also calculated for each diffusing element. The pressure dependence of self-diffusion coefficients in germanium is also verified at high temperatures (876 K–1086 K), in agreement with reported results ranging from ambient pressure up to 600 MPa and is further calculated at pressures up to 3 GPa, where the phase transition to Ge II occurs. - Highlights: • Calculation of diffusivities of n- and p-type dopants in Ge from elastic properties. • Calculation of point defect parameters according to the cBΩ thermodynamic model. • Prediction of the pressure dependence of self-diffusion coefficients in Ge
International Nuclear Information System (INIS)
Zhang, Guoqiang; Zheng, Jiongzhi; Yang, Yongping; Liu, Wenyi
2016-01-01
Highlights: • An off-design performance simulation of triple-pressure reheat HRSG is executed. • The bottoming cycle characteristics of energy transfer/conversion are analyzed. • Concise formulas for the off-design performance of bottoming cycle are proposed. • The accuracy of the formulas is verified under different load control strategies. • The errors of the formulas are generally within 1% at a load of 100–50%. - Abstract: Concise semi-theoretical, semi-empirical formulas are developed in this study to predict the off-design performance of the bottoming cycle of the gas–steam turbine combined cycle. The formulas merely refer to the key thermodynamic design parameters (full load parameters) of the bottoming cycle and off-design gas turbine exhaust temperature and flow, which are convenient in determining the overall performance of the bottoming cycle. First, a triple-pressure reheat heat recovery steam generator (HRSG) is modeled, and thermodynamic analysis is performed. Second, concise semi-theoretical, semi-empirical performance prediction formulas for the bottoming cycle are proposed through a comprehensive analysis of the heat transfer characteristics of the HRSG and the energy conversion characteristics of the steam turbine under the off-design condition. The concise formulas are found to be effective, i.e., fast, simple, and precise in obtaining the thermodynamic parameters for bottoming cycle efficiency, HRSG heat transfer capacity, HRSG efficiency, steam turbine power output, and steam turbine efficiency under the off-design condition. Accuracy is verified by comparing the concise formulas’ calculation results with the simulation results and practical operation data under different load control strategies. The calculation errors are within 1.5% (mainly less than 1% for both simulation and actual operation data) under combined cycle load (gas turbine load) ranging from 50% to 100%. However, accuracy declines sharply when the turbine
Polyakov loop and QCD thermodynamics from the gluon and ghost propagators
International Nuclear Information System (INIS)
Fukushima, Kenji; Kashiwa, Kouji
2013-01-01
We investigate quark deconfinement by calculating the effective potential of the Polyakov loop using the non-perturbative propagators in the Landau gauge measured in the finite-temperature lattice simulation. With the leading term in the 2-particle-irreducible formalism the resultant effective potential exhibits a first-order phase transitions for the pure SU(3) Yang–Mills theory at the critical temperature consistent with the empirical value. We also estimate the thermodynamic quantities to confirm qualitative agreement with the lattice data near the critical temperature. We then apply our effective potential to the chiral model-study and calculate the order parameters and the thermodynamic quantities. Unlike the case in the pure Yang–Mills theory the thermodynamic quantities are sensitive to the temperature dependence of the non-perturbative propagators, while the behavior of the order parameters is less sensitive, which implies the importance of the precise determination of the temperature-dependent propagators
Thermodynamic modelling of a recompression CO_2 power cycle for low temperature waste heat recovery
International Nuclear Information System (INIS)
Banik, Shubham; Ray, Satyaki; De, Sudipta
2016-01-01
Highlights: • Thermodynamic model for recompression T-CO_2 is developed. • Energetic and exergetic analysis compared with S-CO_2 and Reg. Brayton cycle. • Maximum efficiency of 13.6% is obtained for T-CO_2 cycle. • Optimum recompression ratio of 0.48 is obtained for minimum irreversibility. • Reg. Brayton has better efficiency, T-CO_2 offers minimum irreversibility. - Abstract: Due to the rising prices of conventional fossil fuels, increasing the overall thermal efficiency of a power plant is essential. One way of doing this is waste heat recovery. This recovery is most difficult for low temperature waste heat, below 240 °C, which also covers majority of the waste heat source. Carbon dioxide, with its low critical temperature and pressure, offers an advantage over ozone-depleting refrigerants used in Organic Rankine Cycles (ORCs) and hence is most suitable for the purpose. This paper introduces parametric optimization of a transcritical carbon dioxide (T-CO_2) power cycle which recompresses part of the total mass flow of working fluid before entering the precooler, thereby showing potential for higher cycle efficiency. Thermodynamic model for a recompression T-CO_2 power cycle has been developed with waste heat source of 2000 kW and at a temperature of 200 °C. Results obtained from this model are analysed to estimate effects on energetic and exergetic performances of the power cycle with varying pressure and mass recompression ratio. Higher pressure ratio always improves thermodynamic performance of the cycle – both energetic and exergetic. Higher recompression ratio also increases exergetic efficiency of the cycle. However, it increases energy efficiency, only if precooler inlet temperature remains constant. Maximum thermal efficiency of the T-CO_2 cycle with a recompression ratio of 0.26 has been found to be 13.6%. To minimize total irreversibility of the cycle, an optimum ratio of 0.48 was found to be suitable.
Chemical thermodynamics of uranium
International Nuclear Information System (INIS)
Grenthe, I.; Fuger, J.; Lemire, R.J.; Muller, A.B.; Nguyen-Trung Cregu, C.; Wanner, H.
1992-01-01
A comprehensive overview on the chemical thermodynamics of those elements that are of particular importance in the safety assessment of radioactive waste disposal systems is provided. This is the first volume in a series of critical reviews to be published on this subject. The book provides an extensive compilation of chemical thermodynamic data for uranium. A description of procedures for activity corrections and uncertainty estimates is given. A critical discussion of data needed for nuclear waste management assessments, including areas where significant gaps of knowledge exist is presented. A detailed inventory of chemical thermodynamic data for inorganic compounds and complexes of uranium is listed. Data and their uncertainty limits are recommended for 74 aqueous complexes and 199 solid and 31 gaseous compounds containing uranium, and on 52 aqueous and 17 solid auxiliary species containing no uranium. The data are internally consistent and compatible with the CODATA Key Values. The book contains a detailed discussion of procedures used for activity factor corrections in aqueous solution, as well as including methods for making uncertainty estimates. The recommended data have been prepared for use in environmental geochemistry. Containing contributions written by experts the chapters cover various subject areas such a s: oxide and hydroxide compounds and complexes, the uranium nitrides, the solid uranium nitrates and the arsenic-containing uranium compounds, uranates, procedures for consistent estimation of entropies, gaseous and solid uranium halides, gaseous uranium oxides, solid phosphorous-containing uranium compounds, alkali metal uranates, uncertainties, standards and conventions, aqueous complexes, uranium minerals dealing with solubility products and ionic strength corrections. The book is intended for nuclear research establishments and consulting firms dealing with uranium mining and nuclear waste disposal, as well as academic and research institutes
Thermodynamic aspects of dynamical calibration of microbarometers used for IMS applications
International Nuclear Information System (INIS)
Starovojt, Yu.O.; Martysevich, P.N.; Kunakov, A.V.
2006-01-01
This paper describes the method of dynamical calibration of a microbarometer using the chamber with variable volume. The physics of this method is based on the thermodynamic process occurring inside the closed volume and on the corresponding relationships between pressure, volume and temperature changes caused by the movement of the piston attached to the inlet of the chamber. The method has been already used in several applications, however we consider essential to analyze its physical details. The paper gives the description of thermodynamic processes inside the calibration volume, the discussion of thermodynamics need and its effect on the calibration accuracy. (author)
Thermodynamic model of a solid with RKKY interaction and magnetoelastic coupling
Balcerzak, T.; Szałowski, K.; Jaščur, M.
2018-04-01
Thermodynamic description of a model system with magnetoelastic coupling is presented. The elastic, vibrational, electronic and magnetic energy contributions are taken into account. The long-range RKKY interaction is considered together with the nearest-neighbour direct exchange. The generalized Gibbs potential and the set of equations of state are derived, from which all thermodynamic functions are self-consistently obtained. Thermodynamic properties are calculated numerically for FCC structure for arbitrary external pressure, magnetic field and temperature, and widely discussed. In particular, for some parameters of interaction potential and electron concentration corresponding to antiferromagnetic phase, the existence of negative thermal expansion coefficient is predicted.
Thermodynamic calculation of the regions of stable existance of niobium nitride phases
International Nuclear Information System (INIS)
Chernyaev, V.V.; Mitrofanov, B.V.; Moiseev, G.K.; 6030000SU)
1987-01-01
Conditions of formation and stable existence of Nb 2 N and NbN niobium nitrides and the general picture of phase transformations in Nb-N system were determined in wide range of temperatures 1400-4000 K and pressures 10 -9 -10 MPa in result of thermodynamic analysis of Nb-N system using the program, realizing algorithm of total potential minimization. The sufficient nitrogen excess is necessary for formation of Nb 2 N and NbN especially. The temperature stability region and the temperature of NbN and Nb 2 N decomposition is shifted to high temperature region with pressure growth. Pressure region where niobium nitrides are stable, is shifted to high pressure region. The obtained calculation data correspond satisfactorily with experimental publication results. This testifies to possibility of using results of thermodynamic calculations for construction of p-T-diagrams of Nb-N system state
International Nuclear Information System (INIS)
Kooner, Z.S.; Van Hook, W.A.
1986-01-01
An apparatus designed to measure vapor pressure differences between two similar liquids, such as isotopic isomers, or between a solution and its reference solvent at temperatures and pressures extending to the critical point is described. Vapor-phase volume is minimized and pressure is transmitted to the transducer through the liquid, thereby avoiding several experimental difficulties. Liquid can be injected into the heated part of the system by volumetrically calibrated screw injectors, thus permitting measurements of liquid molar volume, compressibility, and expansivity. The addition of a high-pressure circulating pump and injection valve allows the apparatus to be employed as a continuous dilution differential vapor pressure apparatus for determining partial molar free energies of solution. In the second part of the paper data on the vapor pressure, molar volume, compressibility, and expansivity and their isotope effects for C 6 H 6 and C 6 D 6 from room temperature to near the critical temperature are reported
Polylogs, thermodynamics and scaling functions of one-dimensional quantum many-body systems
International Nuclear Information System (INIS)
Guan, X-W; Batchelor, M T
2011-01-01
We demonstrate that the thermodynamics of one-dimensional Lieb-Liniger bosons can be accurately calculated in analytic fashion using the polylog function in the framework of the thermodynamic Bethe ansatz. The approach does away with the need to numerically solve the thermodynamic Bethe ansatz (Yang-Yang) equation. The expression for the equation of state allows the exploration of Tomonaga-Luttinger liquid physics and quantum criticality in an archetypical quantum system. In particular, the low-temperature phase diagram is obtained, along with the scaling functions for the density and compressibility. It has been shown recently by Guan and Ho (arXiv:1010.1301) that such scaling can be used to map out the criticality of ultracold fermionic atoms in experiments. We show here how to map out quantum criticality for Lieb-Liniger bosons. More generally, the polylog function formalism can be applied to a wide range of Bethe ansatz integrable quantum many-body systems which are currently of theoretical and experimental interest, such as strongly interacting multi-component fermions, spinor bosons and mixtures of bosons and fermions. (fast track communication)
Simulation of Cu-Mg metallic glass: Thermodynamics and structure
DEFF Research Database (Denmark)
Bailey, Nicholas; Schiøtz, Jakob; Jacobsen, Karsten Wedel
2004-01-01
We have obtained effective medium theory interatomic potential parameters suitable for studying Cu-Mg metallic glasses. We present thermodynamic and structural results from simulations of such glasses over a range of compositions. We have produced low-temperature configurations by cooling from...... the melt at as slow a rate as practical, using constant temperature and pressure molecular dynamics. During the cooling process we have carried out thermodynamic analyses based on the temperature dependence of the enthalpy and its derivative, the specific heat, from which the glass transition temperature...
Thermodynamic study of alkane-α,ω-diamines - evidence of odd-even pattern of sublimation properties
Czech Academy of Sciences Publication Activity Database
Fulem, Michal; Růžička, K.; Červinka, C.; Bazyleva, A.; Della Gatta, G.
2014-01-01
Roč. 371, Jun (2014), s. 93-105 ISSN 0378-3812 Institutional support: RVO:68378271 Keywords : alkane-diamines * odd–even effect * vapor pressure * sublimation and vaporization thermodynamic properties * statistical thermodynamics Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.200, year: 2014
Critical phenomena of regular black holes in anti-de Sitter space-time
Energy Technology Data Exchange (ETDEWEB)
Fan, Zhong-Ying [Peking University, Center for High Energy Physics, Beijing (China)
2017-04-15
In General Relativity, addressing coupling to a non-linear electromagnetic field, together with a negative cosmological constant, we obtain the general static spherical symmetric black hole solution with magnetic charges, which is asymptotic to anti-de Sitter (AdS) space-times. In particular, for a degenerate case the solution becomes a Hayward-AdS black hole, which is regular everywhere in the full space-time. The existence of such a regular black hole solution preserves the weak energy condition, while the strong energy condition is violated. We then derive the first law and the Smarr formula of the black hole solution. We further discuss its thermodynamic properties and study the critical phenomena in the extended phase space where the cosmological constant is treated as a thermodynamic variable as well as the parameter associated with the non-linear electrodynamics. We obtain many interesting results such as: the Maxwell equal area law in the P-V (or S-T) diagram is violated and consequently the critical point (T{sub *},P{sub *}) of the first order small-large black hole transition does not coincide with the inflection point (T{sub c},P{sub c}) of the isotherms; the Clapeyron equation describing the coexistence curve of the Van der Waals (vdW) fluid is no longer valid; the heat capacity at constant pressure is finite at the critical point; the various exponents near the critical point are also different from those of the vdW fluid. (orig.)
Specific features of the thermodynamics of superionic conductors
International Nuclear Information System (INIS)
Gurevich, Yu.Ya.; Kharkats, Yu.I.
1982-01-01
A review of theoretical and experimental investigations devoted to a study of thermodynamic aspects of the superionic conductivity phenomena for the recent decade is presented. A relation between a superionic conductivity and the disordering of one of the crystal sublattices, the phase transitions of the disordering caused by the point defects interaction, the mechanism of polymorphic transitions conjugated with a partial disordering are considered. The effect of an abrupt change of the ionic conductivity induced by electric field, the thermodynamics of the domain states in superionic conductors and the influence of pressure on phase transitions and ionic conductivity are analyzed
Quantum thermodynamic cycles and quantum heat engines. II.
Quan, H T
2009-04-01
We study the quantum-mechanical generalization of force or pressure, and then we extend the classical thermodynamic isobaric process to quantum-mechanical systems. Based on these efforts, we are able to study the quantum version of thermodynamic cycles that consist of quantum isobaric processes, such as the quantum Brayton cycle and quantum Diesel cycle. We also consider the implementation of the quantum Brayton cycle and quantum Diesel cycle with some model systems, such as single particle in a one-dimensional box and single-mode radiation field in a cavity. These studies lay the microscopic (quantum-mechanical) foundation for Szilard-Zurek single-molecule engine.
Non-equilbrium behavior of low-pressure plasma jets
International Nuclear Information System (INIS)
Chang, C.H.; Pfender, E.
1989-01-01
After establishing the basic equations, some sample calculations are presented to examine the thermodynamic state of the plasma from atmospheric to low pressures (80 mbar). These results indicate the validity of local thermodynamic equilibrium (LTE) at atmospheric pressure as well as strong deviations from LTE at lower pressures especially in terms of chemical equilibrium. Departures from kinetic equilibrium are not as severe as those from chemical equilibrium along the centerline of the jet. However, there are some departures from transitional equilibrium in the fringes of the jet. It is demonstrated that conventional methods based on the LTE assumption are not appropriate for describing low-pressure plasma jets
Thermodynamic behavior of glassy state of structurally related compounds.
Kaushal, Aditya Mohan; Bansal, Arvind Kumar
2008-08-01
Thermodynamic properties of amorphous pharmaceutical forms are responsible for enhanced solubility as well as poor physical stability. The present study was designed to investigate the differences in thermodynamic parameters arising out of disparate molecular structures and associations for four structurally related pharmaceutical compounds--celecoxib, valdecoxib, rofecoxib, and etoricoxib. Conventional and modulated temperature differential scanning calorimetry were employed to study glass forming ability and thermodynamic behavior of the glassy state of model compounds. Glass transition temperature of four glassy compounds was in a close range of 327.6-331.8 K, however, other thermodynamic parameters varied considerably. Kauzmann temperature, strength parameter and fragility parameter showed rofecoxib glass to be most fragile of the four compounds. Glass forming ability of the compounds fared similar in the critical cooling rate experiments, suggesting that different factors were determining the glass forming ability and subsequent behavior of the compounds in glassy state. A comprehensive understanding of such thermodynamic facets of amorphous form would help in rationalizing the approaches towards development of stable glassy pharmaceuticals.
Critical point anomalies include expansion shock waves
Energy Technology Data Exchange (ETDEWEB)
Nannan, N. R., E-mail: ryan.nannan@uvs.edu [Mechanical Engineering Discipline, Anton de Kom University of Suriname, Leysweg 86, PO Box 9212, Paramaribo, Suriname and Process and Energy Department, Delft University of Technology, Leeghwaterstraat 44, 2628 CA Delft (Netherlands); Guardone, A., E-mail: alberto.guardone@polimi.it [Department of Aerospace Science and Technology, Politecnico di Milano, Via La Masa 34, 20156 Milano (Italy); Colonna, P., E-mail: p.colonna@tudelft.nl [Propulsion and Power, Delft University of Technology, Kluyverweg 1, 2629 HS Delft (Netherlands)
2014-02-15
From first-principle fluid dynamics, complemented by a rigorous state equation accounting for critical anomalies, we discovered that expansion shock waves may occur in the vicinity of the liquid-vapor critical point in the two-phase region. Due to universality of near-critical thermodynamics, the result is valid for any common pure fluid in which molecular interactions are only short-range, namely, for so-called 3-dimensional Ising-like systems, and under the assumption of thermodynamic equilibrium. In addition to rarefaction shock waves, diverse non-classical effects are admissible, including composite compressive shock-fan-shock waves, due to the change of sign of the fundamental derivative of gasdynamics.
Fermi, Enrico
1956-01-01
Indisputably, this is a modern classic of science. Based on a course of lectures delivered by the author at Columbia University, the text is elementary in treatment and remarkable for its clarity and organization. Although it is assumed that the reader is familiar with the fundamental facts of thermometry and calorimetry, no advanced mathematics beyond calculus is assumed.Partial contents: thermodynamic systems, the first law of thermodynamics (application, adiabatic transformations), the second law of thermodynamics (Carnot cycle, absolute thermodynamic temperature, thermal engines), the entr
Thermodynamic properties of liquid mixtures of carbon monoxide and methane
Energy Technology Data Exchange (ETDEWEB)
Calado, J.C.G.; Guedes, H.J.R.; Nunes da Ponte, M.; Streett, W.B.
1984-04-01
Researchers conducted pressure-volume-temperature measurements of liquid methane at -230/sup 0/F and of six liquid mixtures of carbon monoxide and methane at -250/sup 0/, -240/sup 0/, and -230/sup 0/F from just above the saturation vapor pressure to the freezing pressure of methane. The excess volume proved to be large and negative at low pressures but less negative as the pressure increased, being almost zero at the highest pressure. Of the thermodynamic functions, excess enthalpy and excess entropy were much more sensitive to pressure than excess Gibbs energy. Conformal solution theory in the van der Waals one-fluid form reproduced the experimental results very successfully.
Thermodynamic Resistance to Matter Flow at The Interface of a Porous Membrane.
Glavatskiy, K S; Bhatia, Suresh K
2016-04-12
Nanoporous materials are important in industrial separation, but their application is subject to strong interfacial barriers to the entry and transport of fluids. At certain conditions the fluid inside and outside the nanoporous material can be viewed as a two-phase system, with an interface between them, which poses an excess resistance to matter flow. We show that there exist two kinds of phenomena which influence the interfacial resistance: hydrodynamic effects and thermodynamic effects, which are independent of each other. Here, we investigate the role of the thermodynamic effects in carbon nanotubes (CNTs) and slit pores and compare the associated thermodynmic resistance with that due to hydrodynamic effects traditionally modeled by the established Sampson expression. Using CH4 and CO2 as model fluids, we show that the thermodynamic resistance is especially important for moderate to high pressures, at which the fluid within the CNT or slit pore is in the condensed state. Further, we show that at such pressures the thermodynamic resistance becomes comparable with the internal resistance to fluid transport at length scales typical of membranes used in fuel cells, and of importance in membrane-based separation, and nanofluidics in general.
Thermodynamic properties of 1-naphthol: Mutual validation of experimental and computational results
International Nuclear Information System (INIS)
Chirico, Robert D.; Steele, William V.; Kazakov, Andrei F.
2015-01-01
Highlights: • Heat capacities were measured for the temperature range 5 K to 445 K. • Vapor pressures were measured for the temperature range 370 K to 570 K. • Computed and derived properties for ideal gas entropies are in excellent accord. • The enthalpy of combustion was measured and shown to be consistent with reliable literature values. • Thermodynamic consistency analysis revealed anomalous literature data. - Abstract: Thermodynamic properties for 1-naphthol (Chemical Abstracts registry number [90-15-3]) in the ideal-gas state are reported based on both experimental and computational methods. Measured properties included the triple-point temperature, enthalpy of fusion, and heat capacities for the crystal and liquid phases by adiabatic calorimetry; vapor pressures by inclined-piston manometry and comparative ebulliometry; and the enthalpy of combustion of the crystal phase by oxygen bomb calorimetry. Critical properties were estimated. Entropies for the ideal-gas state were derived from the experimental studies for the temperature range 298.15 ⩽ T/K ⩽ 600, and independent statistical calculations were performed based on molecular geometry optimization and vibrational frequencies calculated at the B3LYP/6-31+G(d,p) level of theory. The mutual validation of the independent experimental and computed results is achieved with a scaling factor of 0.975 applied to the calculated vibrational frequencies. This same scaling factor was successfully applied in the analysis of results for other polycyclic molecules, as described in a series of recent articles by this research group. This article reports the first extension of this approach to a hydroxy-aromatic compound. All experimental results are compared with property values reported in the literature. Thermodynamic consistency between properties is used to show that several studies in the literature are erroneous. The enthalpy of combustion for 1-naphthol was also measured in this research, and excellent
Thermodynamic analysis of an HCCI engine based system running on natural gas
International Nuclear Information System (INIS)
Djermouni, Mohamed; Ouadha, Ahmed
2014-01-01
Highlights: • A thermodynamic analysis of an HCCI based system has been carried out. • A thermodynamic model has been developed taking into account the gas composition resulting from the combustion process. • The specific heat of the working fluid is temperature dependent. - Abstract: This paper attempts to carry out a thermodynamic analysis of a system composed of a turbocharged HCCI engine, a mixer, a regenerator and a catalytic converter within the meaning of the first and the second law of thermodynamics. For this purpose, a thermodynamic model has been developed taking into account the gas composition resulting from the combustion process and the specific heat temperature dependency of the working fluid. The analysis aims in particular to examine the influence of the compressor pressure ratio, ambient temperature, equivalence ratio, engine speed and the compressor isentropic efficiency on the performance of the HCCI engine. Results show that thermal and exergetic efficiencies increase with increasing the compressor pressure ratio. However, the increase of the ambient temperature involves a decrease of the engine efficiencies. Furthermore, the variation of the equivalence ratio improves considerably both thermal and exergetic efficiencies. As expected, the increase of the engine speed enhances the engine performances. Finally, an exergy losses mapping of the system show that the maximum exergy losses occurs in the HCCI engine
THERMODYNAMIC PARAMETERS OF LEAD SULFIDE CRYSTALS IN THE CUBIC PHASE
Directory of Open Access Journals (Sweden)
T. O. Parashchuk
2016-07-01
Full Text Available Geometric and thermodynamic parameters of cubic PbS crystals were obtained using the computer calculations of the thermodynamic parameters within density functional theory method DFT. Cluster models for the calculation based on the analysis of the crystal and electronic structure. Temperature dependence of energy ΔE and enthalpy ΔH, Gibbs free energy ΔG, heat capacity at constant pressure CP and constant volume CV, entropy ΔS were determined on the basis of ab initio calculations of the crystal structure of molecular clusters. Analytical expressions of temperature dependences of thermodynamic parameters which were approximated with quantum-chemical calculation points have been presented. Experimental results compared with theoretically calculated data.
The Thermodynamics of General and Local Anesthesia
Græsbøll, Kaare; Sasse-Middelhoff, Henrike; Heimburg, Thomas
2014-05-01
General anesthetics are known to cause depression of the freezing point of transitions in biomembranes. This is a consequence of ideal mixing of the anesthetic drugs in the membrane fluid phase and exclusion from the solid phase. Such a generic law provides physical justification of the famous Meyer-Overton rule. We show here that general anesthetics, barbiturates and local anesthetics all display the same effect on melting transitions. Their effect is reversed by hydrostatic pressure. Thus, the thermodynamic behavior of local anesthetics is very similar to that of general anesthetics. We present a detailed thermodynamic analysis of heat capacity profiles of membranes in the presence of anesthetics. This analysis is able to describe experimentally observed calorimetric profiles and permits prediction of the anesthetic features of arbitrary molecules. In addition, we discuss the thermodynamic origin of the cutoff-effect of long-chain alcohols and the additivity of the effect of general and local anesthetics.
Energy Technology Data Exchange (ETDEWEB)
Hendi, S.H., E-mail: hendi@shirazu.ac.ir [Physics Department and Biruni Observatory, College of Sciences, Shiraz University, Shiraz 71454 (Iran, Islamic Republic of); Research Institute for Astronomy and Astrophysics of Maragha (RIAAM), P.O. Box 55134-441, Maragha (Iran, Islamic Republic of); Eslam Panah, B. [Physics Department and Biruni Observatory, College of Sciences, Shiraz University, Shiraz 71454 (Iran, Islamic Republic of); Panahiyan, S. [Physics Department and Biruni Observatory, College of Sciences, Shiraz University, Shiraz 71454 (Iran, Islamic Republic of); Physics Department, Shahid Beheshti University, Tehran 19839 (Iran, Islamic Republic of)
2017-06-10
Violation of Lorentz invariancy in the high energy quantum gravity motivates one to consider an energy dependent spacetime with massive deformation of standard general relativity. In this paper, we take into account an energy dependent metric in the context of a massive gravity model to obtain exact solutions. We investigate the geometry of black hole solutions and also calculate the conserved and thermodynamic quantities, which are fully reproduced by the analysis performed with the standard techniques. After examining the validity of the first law of thermodynamics, we conduct a study regarding the effects of different parameters on thermal stability of the solutions. In addition, we employ the relation between cosmological constant and thermodynamical pressure to study the possibility of phase transition. Interestingly, we will show that for the specific configuration considered in this paper, van der Waals like behavior is observed for different topology. In other words, for flat and hyperbolic horizons, similar to spherical horizon, a second order phase transition and van der Waals like behavior are observed. Furthermore, we use geometrical method to construct phase space and study phase transition and bound points for these black holes. Finally, we obtain critical values in extended phase space through the use of a new method.
Pool critical assembly pressure vessel facility benchmark
International Nuclear Information System (INIS)
Remec, I.; Kam, F.B.K.
1997-07-01
This pool critical assembly (PCA) pressure vessel wall facility benchmark (PCA benchmark) is described and analyzed in this report. Analysis of the PCA benchmark can be used for partial fulfillment of the requirements for the qualification of the methodology for pressure vessel neutron fluence calculations, as required by the US Nuclear Regulatory Commission regulatory guide DG-1053. Section 1 of this report describes the PCA benchmark and provides all data necessary for the benchmark analysis. The measured quantities, to be compared with the calculated values, are the equivalent fission fluxes. In Section 2 the analysis of the PCA benchmark is described. Calculations with the computer code DORT, based on the discrete-ordinates method, were performed for three ENDF/B-VI-based multigroup libraries: BUGLE-93, SAILOR-95, and BUGLE-96. An excellent agreement of the calculated (C) and measures (M) equivalent fission fluxes was obtained. The arithmetic average C/M for all the dosimeters (total of 31) was 0.93 ± 0.03 and 0.92 ± 0.03 for the SAILOR-95 and BUGLE-96 libraries, respectively. The average C/M ratio, obtained with the BUGLE-93 library, for the 28 measurements was 0.93 ± 0.03 (the neptunium measurements in the water and air regions were overpredicted and excluded from the average). No systematic decrease in the C/M ratios with increasing distance from the core was observed for any of the libraries used
Improved Estimates of Thermodynamic Parameters
Lawson, D. D.
1982-01-01
Techniques refined for estimating heat of vaporization and other parameters from molecular structure. Using parabolic equation with three adjustable parameters, heat of vaporization can be used to estimate boiling point, and vice versa. Boiling points and vapor pressures for some nonpolar liquids were estimated by improved method and compared with previously reported values. Technique for estimating thermodynamic parameters should make it easier for engineers to choose among candidate heat-exchange fluids for thermochemical cycles.
[The interarm blood pressure difference in the critically ill patient].
Valls Matarín, Josefa; del Cotillo Fuente, Mercedes; Quintana Riera, Salvador; de la Sierra Iserte, Alejandro
2014-02-04
To evaluate the prevalence of a difference in systolic blood pressure (SBPd) ≥ 10 mmHg between arms in patients admitted in a Critical Care Unit and to examine the clinical characteristics associated with such blood pressure difference. Observational cross-sectional study. Two blood pressure measurements in each arm were carried out at unit admission. The firstly measured arm was chosen at random. One-hundred and sixty-eight patients were studied, with a mean age of 61 (SD=16), 67.3% male and 45% with a previous hypertension diagnosis. On admission, 27.4% presented SBPd ≥ 10 mmHg. Among them, 54% had higher SBP in the right arm and 46% in the left one. A SBPd ≥ 10 mmHg was associated with a previous hypertension diagnosis (67.4 versus 36.9%; Parms. This feature is associated with a previous hypertension diagnosis and reduced consciousness. It should be assessed in the future if the choice of a control arm would help improve patient's care as it would become a more accurate guide for hemodynamic management. Copyright © 2012 Elsevier España, S.L. All rights reserved.
Vapor pressures and thermophysical properties of selected monoterpenoids
Czech Academy of Sciences Publication Activity Database
Štejfa, V.; Dergal, F.; Mokbel, I.; Fulem, Michal; Jose, J.; Růžička, K.
2015-01-01
Roč. 406, Nov (2015), 124-133 ISSN 0378-3812 Institutional support: RVO:68378271 Keywords : monoterpenoids * vapor pressure * heat capacity * ideal - gas thermodynamic properties * vaporization and sublimation enthalpy Subject RIV: BJ - Thermodynamics Impact factor: 1.846, year: 2015
International Nuclear Information System (INIS)
Raisson, Claude
1968-01-01
This research thesis reports the experimental study of flows and of their evolution until critical heating by using appropriate measurement instruments. The objective is to understand how flow evolution may condition critical heating. After a recall of some notions and values related to the study of two-phase flows, and an overview of published works on flow configurations and on critical heating, the author describes test installation and measurement devices, presents the typical test process, reports instrument calibration, and flow configuration tests with water-air flow under low pressure. Results are reported. The author proposes explanations regarding observed phenomena, and a possible scheme to explain the flow evolution until critical heating [fr
Melting line of Krypton in extreme thermodynamic regimes
Directory of Open Access Journals (Sweden)
Giuffre', E
2007-01-01
Full Text Available We have performed extensive computer simulations of the thermodynamic and structural properties of the krypton rare gas modeled by the modified Buckingham exponential-6 interatomic potential. Using a new set of potential parameters, we have found a good agreement with the room temperature equation of state at very high pressure obtained by diamond anvil cell experiments. Moreover, the melting line of the model has been estimated through the Lindemann criterion; the agreement with the low-pressure experiments is excellent, whereas at higher pressure, the model poorly reproduces the typical softening of the experimental melting curve.
Molecular thermodynamics of polymer melts at interfaces
International Nuclear Information System (INIS)
Theodorou, D.N.
1988-09-01
A lattice model is developed for the prediction of structure and thermodynamic properties at free polymer melt surfaces and polymer melt/solid interfaces. Density variations in the interfacial region are taken into account by introducing voids in the lattice, in the spirit of the equation of state theory of Sanchez and Lacombe. Intramolecular energy (chain stiffness) effects are explicitly incorporated. The model is derived through a rigorous statistical mechanical and thermodynamic analysis, which is based on the concept of availability. Two cases are considered: ''full equilibrium,'' whereby the interfacial polymer is taken as free to exchange heat, work and mass with a bulk polymer phase at given temperature and pressure; and ''restricted equilibrium,'' whereby a thin polymer film is allowed to equilibrate locally in response to ambient temperature and pressure, but in which chains do not necessarily have the same chemical potential as in the unconstrained bulk. Techniques are developed for calculating surface tension, adhesion tension, density profiles, chain shape, bond orientation, as well as the distribution of segments of various orders in the interfacial region. 28 refs., 6 figs
Energy Technology Data Exchange (ETDEWEB)
Babelot, J F; Brumme, G D [Institut fuer Angewandte Physik, TH Darmstadt (Germany); Kinsman, P R; Ohse, R W [Commission of the European Communities, European Institute for Transuranium Elements, EURATOM (Germany)
1977-07-01
Nuclear reactor technology requires the vapour pressure of fast breeder reactor fuels up to 6000 K in order to estimate the energy release In hypothetical fast reactor core meltdown accident. Both theoretical and experimental efforts are needed to provide the required data. In principle PVT data can be estimated by appropriate theoretical models, extrapolating measured data, or by purely thermodynamic calculations based on the extrapolation of reliable low temperature thermodynamic data. Direct measurements require the development of new experimental techniques for the extreme temperature range of interest in nuclear technology. The various theoretical approaches are characterized by the application of models which were conceived for simple molecular liquids and by the extrapolation of low temperature vapour pressure data over several thousand degrees, leading to a range In predicted critical point temperatures from 6000 K to almost 10000 K.
EquilTheTA: Thermodynamic and transport properties of complex equilibrium plasmas
International Nuclear Information System (INIS)
Colonna, G.; D'Angola, A.
2012-01-01
EquilTheTA (EQUILibrium for plasma THErmodynamics and Transport Applications) is a web-based software which calculates chemical equilibrium product concentrations from any set of reactants and determines thermodynamic and transport properties for the product mixture in wide temperature and pressure ranges. The program calculates chemical equilibrium by using a hierarchical approach, thermodynamic properties and transport coefficients starting from recent and accurate databases of atomic and molecular energy levels and collision integrals. In the calculations, Debye length and cut-off are consistently updated and virial corrections (up to third order) can be considered. Transport coefficients are calculated by using high order approximations of the Chapman-Enskog method.
International Nuclear Information System (INIS)
Lim, Gyeong Hui
2008-03-01
This book consists of 15 chapters, which are basic conception and meaning of statistical thermodynamics, Maxwell-Boltzmann's statistics, ensemble, thermodynamics function and fluctuation, statistical dynamics with independent particle system, ideal molecular system, chemical equilibrium and chemical reaction rate in ideal gas mixture, classical statistical thermodynamics, ideal lattice model, lattice statistics and nonideal lattice model, imperfect gas theory on liquid, theory on solution, statistical thermodynamics of interface, statistical thermodynamics of a high molecule system and quantum statistics
Thermodynamic and Quantum Thermodynamic Analyses of Brownian Movement
Gyftopoulos, Elias P.
2006-01-01
Thermodynamic and quantum thermodynamic analyses of Brownian movement of a solvent and a colloid passing through neutral thermodynamic equilibrium states only. It is shown that Brownian motors and E. coli do not represent Brownian movement.
Determination of the thermodynamic properties of water from the speed of sound
International Nuclear Information System (INIS)
Trusler, J.P. Martin; Lemmon, Eric W.
2017-01-01
Highlights: • We analyse error propagation in thermodynamic integration of fluid-phase sound speed data. • A new correlation of the speed of sound in liquid water is derived. • Thermodynamic integration is carried out for pure water. • Derived properties considered include density, isobaric expansivity and isobaric specific heat capacity. - Abstract: Thermodynamic properties of compressed liquids may be obtained from measurements of the speed of sound by means of thermodynamic integration subject to initial values of density and isobaric specific heat capacity along a single low-pressure isobar. In this paper, we present an analysis of the errors in the derived properties arising from perturbations in both the speed-of-sound surface and the initial values. These errors are described in first order by a pair of partial differential equations that we integrate for the example case of water with various scenarios for the errors in the sound speed and the initial values. The analysis shows that errors in either the speed of sound or the initial values of density that are rapidly oscillating functions of temperature have a disproportionately large influence on the derived properties, especially at low temperatures. In view of this, we have obtained a more accurate empirical representation of the recent experimental speed-of-sound data for water [Lin and Trusler, J. Chem. Phys. 136, (2012) 094511] and use this in a new thermodynamic integration to obtain derived properties including density, isobaric heat capacity and isobaric thermal expansivity at temperatures between (253.15 and 473.15) K at pressures up to 400 MPa. The densities obtained in this way are in very close agreement with those reported by Lin and Trusler, but the isobaric specific heat capacity and the isobaric expansivity both differ significantly in the extremes of low temperatures and high pressures.
International Nuclear Information System (INIS)
Chirico, Robert D.; Kazakov, Andrei F.; Steele, William V.
2012-01-01
Highlights: ► Heat capacities were measured for the temperature range 5 K to 520 K. ► Vapor pressures were measured for the temperature range 368 K to 668 K. ► The enthalpy of combustion was measured and the enthalpy of formation was derived. ► Calculated and derived properties for the ideal gas are in excellent accord. ► Thermodynamic consistency analysis revealed anomalous literature data. - Abstract: Measurements leading to the calculation of thermodynamic properties for 9-fluorenone (IUPAC name 9H-fluoren-9-one and Chemical Abstracts registry number [486-25-9]) in the ideal-gas state are reported. Experimental methods were adiabatic heat-capacity calorimetry, inclined-piston manometry, comparative ebulliometry, and combustion calorimetry. Critical properties were estimated. Molar entropies for the ideal-gas state were derived from the experimental studies at selected temperatures T between T = 298.15 K and T = 600 K, and independent statistical calculations were performed based on molecular geometry optimization and vibrational frequencies calculated at the B3LYP/6 − 31 + G(d,p) level of theory. Values derived with the independent methods are shown to be in excellent accord with a scaling factor of 0.975 applied to the calculated frequencies. This same scaling factor was successfully applied in the analysis of results for other polycyclic molecules, as described in recent articles by this research group. All experimental results are compared with property values reported in the literature. Thermodynamic consistency between properties is used to show that several studies in the literature are erroneous.
Theoretical investigation of the thermodynamic properties of metallic thin films
International Nuclear Information System (INIS)
Hung, Vu Van; Phuong, Duong Dai; Hoa, Nguyen Thi; Hieu, Ho Khac
2015-01-01
The thermodynamic properties of metallic thin films with face-centered cubic structure at ambient conditions were investigated using the statistical moment method including the anharmonicity effects of thermal lattice vibrations. The analytical expressions of Helmholtz free energy, lattice parameter, linear thermal expansion coefficient, specific heats at the constant volume and constant pressure were derived in terms of the power moments of the atomic displacements. Numerical calculations of thermodynamic properties have been performed for Au and Al thin films and compared with those of bulk metals. This research proposes that thermodynamic quantities of thin films approach the values of bulk when the thickness of thin film is about 70 nm. - Highlights: • Thermodynamic properties of thin films were investigated using the moment method. • Expressions of Helmholtz energy, expansion coefficient, specific heats were derived. • Calculations for Au, Al thin films were performed and compared with those of bulks
Theoretical investigation of the thermodynamic properties of metallic thin films
Energy Technology Data Exchange (ETDEWEB)
Hung, Vu Van [Vietnam Education Publishing House, 81 Tran Hung Dao, Hanoi (Viet Nam); Phuong, Duong Dai [Hanoi National University of Education, 136 Xuan Thuy, Hanoi (Viet Nam); Hoa, Nguyen Thi [University of Transport and Communications, Lang Thuong, Dong Da, Hanoi (Viet Nam); Hieu, Ho Khac, E-mail: hieuhk@duytan.edu.vn [Institute of Research and Development, Duy Tan University, K7/25 Quang Trung, Danang (Viet Nam)
2015-05-29
The thermodynamic properties of metallic thin films with face-centered cubic structure at ambient conditions were investigated using the statistical moment method including the anharmonicity effects of thermal lattice vibrations. The analytical expressions of Helmholtz free energy, lattice parameter, linear thermal expansion coefficient, specific heats at the constant volume and constant pressure were derived in terms of the power moments of the atomic displacements. Numerical calculations of thermodynamic properties have been performed for Au and Al thin films and compared with those of bulk metals. This research proposes that thermodynamic quantities of thin films approach the values of bulk when the thickness of thin film is about 70 nm. - Highlights: • Thermodynamic properties of thin films were investigated using the moment method. • Expressions of Helmholtz energy, expansion coefficient, specific heats were derived. • Calculations for Au, Al thin films were performed and compared with those of bulks.
Nedergaard, Helene K; Haberlandt, Trine; Toft, Palle; Jensen, Hanne Irene
2018-02-01
Pressure ulcers still pose a significant clinical challenge to critically ill patients. This study is a substudy of the multicenter NONSEDA-trial, where critically ill patients were randomised to sedation or non-sedation during mechanical ventilation. The objective of this substudy was to assess if non-sedation affected the occurrence of pressure ulcers. Retrospective assessment of data from a single NONSEDA-trial site. Mixed intensive care unit. The occurrence of pressure ulcers, described by grade and location. 205 patients were included. Patients with pressure ulcers in the two groups were comparable with regards to baseline data. There were 44 ulcers in 32 patients in the sedated group and 31 ulcers in 25 patients in the non-sedated group (p=0.08). 64% of the ulcers in sedated patients were located on sacrum and heels, whereas 68% of the ulcers in non-sedated patients were related to equipment (p=0.03). Non-sedation did not significantly reduce the number of pressure ulcers. Non-sedation significantly affected the location of ulcers: non-sedated patients mainly had ulcers related to equipment, whereas sedated patients mainly had ulcers on the sacrum and heels. Copyright © 2017 Elsevier Ltd. All rights reserved.
Thermodynamics of spinning branes and their dual field theories
DEFF Research Database (Denmark)
Harmark, Troels; Obers, N. A.
2000-01-01
We discuss general spinning p-branes of string and M-theory and use their thermodynamics along with the correspondence between near-horizon brane solutions and field theories with 16 supercharges to describe the thermodynamic behavior of these theories in the presence of voltages under the R......-symmetry. The thermodynamics is used to provide two pieces of evidence in favor of a smooth interpolation function between the free energy at weak and strong coupling of the field theory. (i) A computation of the boundaries of stability shows that for the D2, D3, D4, M2 and M5-branes the critical values of Omega/T in the two...... limits are remarkably close and (ii) The tree-level R^4 corrections to the spinning D3-brane generate a decrease in the free energy at strong coupling towards the weak coupling result. We also comment on the generalization to spinning brane bound states and their thermodynamics, which are relevant...
International Nuclear Information System (INIS)
Hawrylak, B.; Palepu, R.; Tremaine, Peter R.
2006-01-01
Apparent molar volumes of aqueous methyldiethanolamine and its salt were determined with platinum vibrating tube densitometers over a range of temperatures from 283K= o , heat capacities C p o , and isothermal compressibilities κ T o . The standard partial molar volumes V o for the neutral amine and its salt show increasingly positive and negative values, respectively, at high temperatures and pressures, as predicted by corresponding states and group additivity arguments. The density model and the revised Helgeson-Kirkham-Flowers (HKF) model have been used to represent the temperature and pressure dependence of the standard partial molar properties to yield a full thermodynamic description of the system
A digital simulation of a pressurizer in a PWR nuclear power plant
International Nuclear Information System (INIS)
Sato, E.F.
1980-11-01
A model for pressurizer digital simulation of a PWR nuclear power plant during transients, considering all pressurizer control features, is presented. The pressurizer is divided into two regions separated by a water-vapor interface and non-equilibrium conditions are considered. The particular thermodynamic process followed during insurge and outsurges is determined at each instant of analysis without any previous assumption. The pressure behavior is defined by an explicit equation in any of four possible pressurizer thermodynamic conditions. Thermodynamic properties of steam and water are computed by ASME subroutines and the mathematical formulation presented in this study was programed in FORTRAN IV for a Burroughs-6700 digital computer system. This program was employed to simulate the Shippingport Atomic Power Station and Almirante Alvaro Alberto Nuclear Power Plant - Unit 1 pressurizers. The test results compared with experimental or vendor data show the validity of this analysis method. (Author) [pt
Thermodynamic geometry and phase transitions of dyonic charged AdS black holes
Energy Technology Data Exchange (ETDEWEB)
Chaturvedi, Pankaj; Sengupta, Gautam [Indian Institute of Technology Kanpur, Department of Physics, Kanpur (India); Das, Anirban [Tata Institute of Fundamental Research, Department of Theoretical Physics, Mumbai (India)
2017-02-15
We investigate phase transitions and critical phenomena of four dimensional dyonic charged AdS black holes in the framework of thermodynamic geometry. In a mixed canonical-grand canonical ensemble with a fixed electric charge and varying magnetic charge these black holes exhibit a liquid-gas like first order phase transition culminating in a second order critical point similar to the van der Waals gas. We show that the thermodynamic scalar curvature R for these black holes follow our proposed geometrical characterization of the R-crossing Method for the first order liquid-gas like phase transition and exhibits a divergence at the second order critical point. The pattern of R crossing and divergence exactly corresponds to those of a van der Waals gas described by us in an earlier work. (orig.)
Critical sizes and critical characteristics of nanoclusters, nanostructures and nanomaterials
International Nuclear Information System (INIS)
Suzdalev, I.P.
2005-01-01
Full text: Critical sizes and characteristics of nanoclusters and nanostructures are introduced as the parameters of nanosystems and nanomaterials. The next critical characteristics are considered: atomic and electronic 'magic number', critical size of cluster nucleation, critical size of melting-freezing of cluster, critical size of quantum (laser) radiation, critical sizes for the single electron conductivity, critical energy and magnetic field for the magnetic tunneling, critical cluster sizes for the giant magnetic resistance, critical size of the first order magnetic phase transition. The critical characteristics are estimated by thermodynamic approaches, by Moessbauer spectroscopy, AFM, heat capacity, SQUID magnetometry and other technique, The influence of cluster-cluster interactions, cluster-matrix interactions and cluster defects on cluster atomic dynamics, cluster melting, cluster critical sizes, Curie or Neel points and the character of magnetic phase transitions were investigated. The applications of critical size and critical characteristic parameters for the nanomaterial characterization are considered
International Nuclear Information System (INIS)
Chen, Yi; Han, Wei; Jin, Hongguang
2016-01-01
Highlights: • This paper proposes a new thermal compressor model with boost pressure ratio. • The proposed model is an effective way to optimize the absorption-generation process. • Boost pressure ratio is a key parameter in the proposed thermal compressor model. • The optimum boost pressure ratios for two typical refrigeration systems are obtained. - Abstract: The absorption refrigeration cycle is a basic cycle that establishes the systems for utilizing mid-low temperature heat sources. A new thermal compressor model with a key parameter of boost pressure ratio is proposed to optimize the absorption-generation process. The ultimate generation pressure and boost pressure ratio are used to represent the potential and operating conditions of the thermal compressor, respectively. Using the proposed thermal compressor model, the operation mechanism and requirements of the absorption refrigeration system and absorption-compression refrigeration system are elucidated. Furthermore, the two typical heat conversion systems are optimized based on the thermal compressor model. The optimum boost pressure ratios of the absorption refrigeration system and the absorption-compression refrigeration system are 0.5 and 0.75, respectively. For the absorption refrigeration system, the optimum generation temperature is 125.31 °C at the cooling water temperature of 30 °C, which is obtained by simple thermodynamic calculation. The optimized thermodynamic performance of the absorption-compression refrigeration system is 16.7% higher than that of the conventional absorption refrigeration system when the generation temperature is 100 °C. The thermal compressor model proposed in this paper is an effective method for simplifying the optimization of the thermodynamic systems involving an absorption-generation process.
International Nuclear Information System (INIS)
Mondal, Subha; De, Sudipta
2015-01-01
For energy utilization from low temperature waste heat, CO 2 is a potential working fluid due to its lower critical temperature. In this work, assuming finite quantity of flue gas available at low temperature (200 °C), a thermodynamic model is developed for a transcritical CO 2 power cycle utilizing turbine bleed gas for regenerative heating. Analysis show that the cycle performance improves with higher value of bleed ratio. However, for a specified bleed pressure and bleed gas temperature at the regenerator exit, maximum practical value of bleed ratio may be fixed by considering the exponential growth of the regenerator size (specified by NTU (number of transfer unit)). Most significant observation is the existence of optimum bleed pressures corresponding to maximum 1st law efficiency or minimum cycle irreversibility for specified values of remaining cycle parameters. - Highlights: • Thermodynamic model for Transcritical CO 2 cycle with bleed gas are developed. • Effects of bleed ratio, pressure, and regenerator exit gas temperature are studied. • 1st and 2nd law efficiencies are estimated. • An optimum bleed pressure for maximum 1st and 2nd efficiencies is obtained. • Maximum value of 1st law efficiency is limited by regenerator size
Levashov, V. A.; Lyubchenko, K. Yu
2017-08-01
This article describes the physical processes that occur in the stage flow part of the compressor while it is operating and can create conditions for the occurrence of forced vibrations, which in turn can lead to the destruction of the impellers. Critical conditions of compressor operation are determined. To understand that critical condition of operation is cause of the destruction of the impellers, transient CFD analysis was carried for test stage of compressor. The obtained pressure fluctuation amplitudes allow to evaluate the critical conditions of compressor operation.
International Nuclear Information System (INIS)
Duthil, P
2014-01-01
The goal of this paper is to present a general thermodynamic basis that is useable in the context of superconductivity and particle accelerators. The first part recalls the purpose of thermodynamics and summarizes its important concepts. Some applications, from cryogenics to magnetic systems, are covered. In the context of basic thermodynamics, only thermodynamic equilibrium is considered
Energy Technology Data Exchange (ETDEWEB)
Duthil, P [Orsay, IPN (France)
2014-07-01
The goal of this paper is to present a general thermodynamic basis that is useable in the context of superconductivity and particle accelerators. The first part recalls the purpose of thermodynamics and summarizes its important concepts. Some applications, from cryogenics to magnetic systems, are covered. In the context of basic thermodynamics, only thermodynamic equilibrium is considered.
Equilibrium dissociation pressures of lithium hydride and lithium deuteride
International Nuclear Information System (INIS)
Smith, H.M.; Webb, R.E.
1977-12-01
The equilibrium dissociation pressures of plateau composition lithium hydride and lithium deuteride have been measured from 450 to 750 0 C. These data were used to derive the relationship of dissociation pressure with temperature over this range and to calculate several thermodynamic properties of these materials. Thermodynamic properties determined included the enthalpy, entropy, and free energy of formation; the enthalpy and entropy of fusion; and the melting points
International Nuclear Information System (INIS)
Fernandes, M.P.
1973-02-01
An experimental determination was made of heat transfer critical conditions in a circular channel, uniformly heated, and internally cooled by water in ascending forced convection, under a pressure slightly above atmospheric pressure. Measurements were made of water flow, pressure, electric power temperature and heating, and a systematic analysis was made of the system's parameters. The values obtained for the heat critical flux are circa 50% lower than those predicted by Becker and Biasi and this is accounted to flowing instabilities of thermo-hydrodynamic nature. It is suggested that the flowing channels of circuits aiming at the study of the boiling crisis phenomenon be expanded in its upper extremity, and that the coolant circulation be kept through a pump with a pressure X flow characteristic as vertical as possible
Thermodynamic isotope effects of D2 and T2 reaction with uranium
International Nuclear Information System (INIS)
Huang Gang; Long Xinggui; Liang Jianhua; Yang Benfu; Liu Wenke
2010-01-01
The p-c-T curves of deuterium and tritium absorption by uranium and p-t curves of desorption were measured. The balance pressure of absorption and desorption on different temperatures were got and then the thermodynamic parameters were determined according to the Van't Hoff equation. It shows that the balance pressure of deuterium absorption is lower than that of tritium absorption on the same temperature and atom ratio. It has the same phenomena for desorption but there are obvious hysteresis effect for reversible process of absorption and desorption. There are a little thermodynamic isotope effects when deuterium and tritium absorption and desorption by uranium estimating from enthalpy and entropy values. (authors)
International Nuclear Information System (INIS)
Tomita, M; Suzuki, K; Fukumoto, Y; Ishihara, A; Akasaka, T; Kobayashi, Y; Maeda, A; Takayasu, M
2015-01-01
A 2 m length Twisted Stacked-Tape Cable (TSTC) conductor which was fabricated by 32-YBCO-tapes (4 mm width) with a 200 mm twist pitch was investigated at various temperatures near 77 K in subcooled- and pressurized-liquid nitrogen. The critical current of the TSTC cable which was 1.45 kA at 77 K measured from 64 K to 85 K by controlling the equilibrium vapor pressure of nitrogen bath and were varied from 3.65 kA at 64 K to 0.42 kA at 85 K. The temperature dependence of cables’ critical current agrees with that of the 4 mm width YBCO tape. These results are encouraging for applications of a compact Twisted Stacked-Tape Cable application in railway systems. (paper)
Vapor pressure and thermodynamics of beryllium carbide
International Nuclear Information System (INIS)
Rinehart, G.H.; Behrens, R.G.
1980-01-01
The vapor pressure of beryllium carbide has been measured over the temperature range 1388 to 1763 K using Knudsen-effusion mass spectrometry. Vaporization occurs incongruently according to the reaction Be 2 C(s) = 2Be(g) + C(s). The equilibrium vapor pressure above the mixture of Be 2 C and C over the experimental temperature range is (R/J K -1 mol -1 )ln(p/Pa) = -(3.610 +- 0.009) x 10 5 (K/T) + (221.43 +- 1.06). The third-law enthalpy change for the above reaction obtained from the present vapor pressures is ΔH 0 (298.15 K) = (740.5 +- 0.1) kJ mol -1 . The corresponding second-law result is ΔH 0 (298.15 K) = (732.0 +- 1.8) kJ mol -1 . The enthalpy of formation for Be 2 C(s) calculated from the present third-law vaporization enthalpy and the enthalpy of formation of Be(g) is ΔH 0 sub(f)(298.15 K) = -(92.5 +- 15.7) kJ mol -1 . (author)
Differential thermodynamic signature of carbon nanomaterials using amphiphilic micellar probe
Bhattacharyya, Tamoghna; Dasgupta, Anjan Kr
2018-04-01
The thermodynamic signature of single-wall carbon nanotubes (SWCNTs), multi-walled carbon nanotubes (MWCNTs) and reduced graphene oxide (rG-O) using amphiphilic micellar probe has been explored. The study reveals an intricate correlation between nano-surface topology and calorimetric profile of SWCNTs, MWCNTs and rG-O. The critical micelle concentration (CMC) is found to be sensitive to the topological diversity of nanomaterials. The study explores a thermodynamic approach to characterize the nano-surface topology of SWCNTs, MWCNTs and graphene surface.
Thermodynamic Properties of Actinides and Actinide Compounds
Konings, Rudy J. M.; Morss, Lester R.; Fuger, Jean
The necessity of obtaining accurate thermodynamic quantities for the actinide elements and their compounds was recognized at the outset of the Manhattan Project, when a dedicated team of scientists and engineers initiated the program to exploit nuclear energy for military purposes. Since the end of World War II, both fundamental and applied objectives have motivated a great deal of further study of actinide thermodynamics. This chapter brings together many research papers and critical reviews on this subject. It also seeks to assess, to systematize, and to predict important properties of the actinide elements, ions, and compounds, especially for species in which there is significant interest and for which there is an experimental basis for the prediction.
Kinetic and thermodynamic control of butyrate conversion in non-defined methanogenic communities.
Junicke, H; van Loosdrecht, M C M; Kleerebezem, R
2016-01-01
Many anaerobic conversions proceed close to thermodynamic equilibrium and the microbial groups involved need to share their low energy budget to survive at the thermodynamic boundary of life. This study aimed to investigate the kinetic and thermodynamic control mechanisms of the electron transfer during syntrophic butyrate conversion in non-defined methanogenic communities. Despite the rather low energy content of butyrate, results demonstrate unequal energy sharing between the butyrate-utilizing species (17 %), the hydrogenotrophic methanogens (9-10 %), and the acetoclastic methanogens (73-74 %). As a key finding, the energy disproportion resulted in different growth strategies of the syntrophic partners. Compared to the butyrate-utilizing partner, the hydrogenotrophic methanogens compensated their lower biomass yield per mole of electrons transferred with a 2-fold higher biomass-specific electron transfer rate. Apart from these thermodynamic control mechanisms, experiments revealed a ten times lower hydrogen inhibition constant on butyrate conversion than proposed by the Anaerobic Digestion Model No. 1, suggesting a much stronger inhibitory effect of hydrogen on anaerobic butyrate conversion. At hydrogen partial pressures exceeding 40 Pa and at bicarbonate limited conditions, a shift from methanogenesis to reduced product formation was observed which indicates an important role of the hydrogen partial pressure in redirecting electron fluxes towards reduced products such as butanol. The findings of this study demonstrate that a careful consideration of thermodynamics and kinetics is required to advance our current understanding of flux regulation in energy-limited syntrophic ecosystems.
Mavris, Dimitri; Roth, Bryce; McDonald, Rob
2002-01-01
The objective of this report is to provide a tool to facilitate the application of thermodynamic work potential methods to aircraft and engine analysis. This starts with a discussion of the theoretical background underlying these methods, which is then used to derive various equations useful for thermodynamic analysis of aircraft engines. The work potential analysis method is implemented in the form of a set of working charts and tables that can be used to graphically evaluate work potential stored in high-enthalpy gas. The range of validity for these tables is 300 to 36,000 R, pressures between between 0.01 atm and 100 atm, and fuel-air ratios from zero to stoichiometric. The derivations and charts assume mixtures of Jet-A and air as the working fluid. The thermodynamic properties presented in these charts were calculated based upon standard thermodynamic curve fits.
QCD thermodynamics from an imaginary μB: Results on the four flavor lattice model
International Nuclear Information System (INIS)
D'Elia, Massimo; Lombardo, Maria-Paola
2004-01-01
We study four flavor QCD at nonzero temperature and density by analytic continuation from an imaginary chemical potential. The explored region is T=0.95T c c , and the baryochemical potentials range from 0 to ≅500 MeV. Observables include the number density, the order parameter for chiral symmetry, and the pressure, which is calculated via an integral method at fixed temperature and quark mass. The simulations are carried out on a 16 3 x4 lattice, and the mass dependence of the results is estimated by exploiting the Maxwell relations. In the hadronic region, we confirm that the results are consistent with a simple resonance hadron gas model, and we estimate the critical density by combining the results for the number density with those for the critical line. In the hot phase, above the end point of the Roberge-Weiss transition T E ≅1.1T c , the results are consistent with a free lattice model with a fixed effective number of flavor slightly different from four. We confirm that confinement and chiral symmetry are coincident by a further analysis of the critical line, and we discuss the interrelation between thermodynamics and critical behavior. We comment on the strength and weakness of the method, and propose further developments
Thermodynamic properties of sea air
Directory of Open Access Journals (Sweden)
R. Feistel
2010-02-01
Full Text Available Very accurate thermodynamic potential functions are available for fluid water, ice, seawater and humid air covering wide ranges of temperature and pressure conditions. They permit the consistent computation of all equilibrium properties as, for example, required for coupled atmosphere-ocean models or the analysis of observational or experimental data. With the exception of humid air, these potential functions are already formulated as international standards released by the International Association for the Properties of Water and Steam (IAPWS, and have been adopted in 2009 for oceanography by IOC/UNESCO.
In this paper, we derive a collection of formulas for important quantities expressed in terms of the thermodynamic potentials, valid for typical phase transitions and composite systems of humid air and water/ice/seawater. Particular attention is given to equilibria between seawater and humid air, referred to as "sea air" here. In a related initiative, these formulas will soon be implemented in a source-code library for easy practical use. The library is primarily aimed at oceanographic applications but will be relevant to air-sea interaction and meteorology as well.
The formulas provided are valid for any consistent set of suitable thermodynamic potential functions. Here we adopt potential functions from previous publications in which they are constructed from theoretical laws and empirical data; they are briefly summarized in the appendix. The formulas make use of the full accuracy of these thermodynamic potentials, without additional approximations or empirical coefficients. They are expressed in the temperature scale ITS-90 and the 2008 Reference-Composition Salinity Scale.
Thevelein, Johan M.; Van Assche, Jozef A.; Carlier, Albert R.; Heremans, Karel
1979-01-01
The thermodynamic parameters for the heat activation of the sporangiospores of Phycomyces blakesleeanus were determined. For the apparent activation enthalpy (ΔH#) a value of 1,151 kJ/mol was found, whereas a value of 3,644 J./°K·mol was calculated for the apparent activation entropy (ΔS#). n-Alcohols (from methanol to octanol), phenethyl alcohol, and furfural lowered the activation temperature of P. blakesleeanus spores. The heat resistance of the spores was lowered concomitantly. The effect of the alcohols was a linear function of the concentration in the range that could be applied. When the log of the concentration needed to produce an equal shift of the activation temperature was plotted for each alochol against the log of the octanol/water partition coefficient, a straight line was obtained. The free energy of adsorption of the n-alcohols to their active sites was calculated to be −2,487 J/mol of CH2 groups. Although still inconclusive, this points toward an involvement of protein in the activation process. The effect of phenethyl alcohol was similar to the effect of n-alcohols, but furfural produced a greater shift than would be expected from the value of its partition coefficient. When the heat activation of the spores was performed under high pressure, the activation temperature was raised by 2 to 4°K/1,000 atm. However, with pressures higher than 1,000 atm (1.013 × 105 kPa) the activation temperature was lowered until the pressure became lethal (more than 2,500 atm). It is known that membrane phase transition temperatures are shifted upward by about 20°K/1,000 atm and that protein conformational changes are shifted upward by 2 to 6°K/1,000 atm. Consequently, heat activation of fungal spores seems to be triggered by a protein conformational change and not by a membrane phase transition. Activation volumes of −54.1 cm3/mol at 38°C and −79.3 cm2/mol at 40°C were found for the lowering effect of high pressure on the heat activation temperature
International Nuclear Information System (INIS)
Garcia-Moliner, F.
1975-01-01
Basic thermodynamics of a system consisting of two bulk phases with an interface. Solid surfaces: general. Discussion of experimental data on surface tension and related concepts. Adsorption thermodynamics in the Gibbsian scheme. Adsorption on inert solid adsorbents. Systems with electrical charges: chemistry and thermodynamics of imperfect crystals. Thermodynamics of charged surfaces. Simple models of charge transfer chemisorption. Adsorption heat and related concepts. Surface phase transitions
Thermodynamic analysis of hydrogen production from biomass gasification
International Nuclear Information System (INIS)
Cohce, M.K.; Dincer, I.; Rosen, M.A.
2009-01-01
'Full Text': Biomass resources have the advantage of being renewable and can therefore contribute to renewable hydrogen production. In this study, an overview is presented of hydrogen production methods in general, and biomass-based hydrogen production in particular. For two methods in the latter category (direct gasification and pyrolysis), assessments are carried out, with the aim of investigating the feasibility of producing hydrogen from biomass and better understanding the potential of biomass as a renewable energy source. A simplified model is presented here for biomass gasification based on chemical equilibrium considerations, and the effects of temperature, pressure and the Gibbs free energy on the equilibrium hydrogen yield are studied. Palm oil (designated C 6 H 10 O 5 ), one of the most common biomass resources in the world, is considered in the analyses. The gasifier is observed to be one of the most critical components of a biomass gasification system, and is modeled using stoichiometric reactions. Various thermodynamic efficiencies are evaluated, and both methods are observed to have reasonably high efficiencies. (author)
Black Hole Thermodynamics in an Undergraduate Thermodynamics Course.
Parker, Barry R.; McLeod, Robert J.
1980-01-01
An analogy, which has been drawn between black hole physics and thermodynamics, is mathematically broadened in this article. Equations similar to the standard partial differential relations of thermodynamics are found for black holes. The results can be used to supplement an undergraduate thermodynamics course. (Author/SK)
Quantum Thermodynamics at Strong Coupling: Operator Thermodynamic Functions and Relations
Directory of Open Access Journals (Sweden)
Jen-Tsung Hsiang
2018-05-01
Full Text Available Identifying or constructing a fine-grained microscopic theory that will emerge under specific conditions to a known macroscopic theory is always a formidable challenge. Thermodynamics is perhaps one of the most powerful theories and best understood examples of emergence in physical sciences, which can be used for understanding the characteristics and mechanisms of emergent processes, both in terms of emergent structures and the emergent laws governing the effective or collective variables. Viewing quantum mechanics as an emergent theory requires a better understanding of all this. In this work we aim at a very modest goal, not quantum mechanics as thermodynamics, not yet, but the thermodynamics of quantum systems, or quantum thermodynamics. We will show why even with this minimal demand, there are many new issues which need be addressed and new rules formulated. The thermodynamics of small quantum many-body systems strongly coupled to a heat bath at low temperatures with non-Markovian behavior contains elements, such as quantum coherence, correlations, entanglement and fluctuations, that are not well recognized in traditional thermodynamics, built on large systems vanishingly weakly coupled to a non-dynamical reservoir. For quantum thermodynamics at strong coupling, one needs to reexamine the meaning of the thermodynamic functions, the viability of the thermodynamic relations and the validity of the thermodynamic laws anew. After a brief motivation, this paper starts with a short overview of the quantum formulation based on Gelin & Thoss and Seifert. We then provide a quantum formulation of Jarzynski’s two representations. We show how to construct the operator thermodynamic potentials, the expectation values of which provide the familiar thermodynamic variables. Constructing the operator thermodynamic functions and verifying or modifying their relations is a necessary first step in the establishment of a viable thermodynamics theory for
Thermodynamic modeling of the Sc-Zn system coupled with first-principles calculation
Directory of Open Access Journals (Sweden)
Tang C.
2012-01-01
Full Text Available The Sc-Zn system has been critically reviewed and assessed by means of CALPHAD (CALculation of PHAse Diagram approach. By means of first-principles calculation, the enthalpies of formation at 0 K for the ScZn, ScZn2, Sc17Zn58, Sc3Zn17 and ScZn12 have been computed with the desire to assist thermodynamic modeling. A set of self-consistent thermodynamic parameters for the Sc-Zn system is then obtained. The calculated phase diagram and thermodynamic properties agree well with the experimental data and first-principles calculations, respectively.
Thermodynamic tables to accompany Modern engineering thermodynamics
Balmer, Robert T
2011-01-01
This booklet is provided at no extra charge with new copies of Balmer's Modern Engineering Thermodynamics. It contains two appendices. Appendix C contains 40 thermodynamic tables, and Appendix D consists of 6 thermodynamic charts. These charts and tables are provided in a separate booklet to give instructors the flexibility of allowing students to bring the tables into exams. The booklet may be purchased separately if needed.
New application of the Knudsen method for a direct determination of thermodynamic activities
International Nuclear Information System (INIS)
Peltner, H.E.; Herzig, C.
1978-01-01
A new variation of the Knudsen effusion method is presented, which allows the direct and sensitive determination of thermodynamic activities in a binary or multi-component solid or liquid solution. Radioisotopes were used for measuring the vapor pressure ratio. In the system Ag-Au the thermodynamic activities of both components were determined using 105 Ag, sup(110m)Ag, 195 Au, and 198 Au. (author)
Influence of aluminium content on thermodynamic function of LaNi5-xAlx
International Nuclear Information System (INIS)
Xiong Yifu; Cheng Huchi; Luo Deli
2000-01-01
Hydriding thermodynamic parameters were measured on alloys of the general composition of LaNi 5-x Al x (x = 0.0, 0.1, 0.2, 0.3) under isothermal and isochoric conditions. The results show that the equilibrium pressure, hydrogen capacity and thermodynamic parameters such as ΔH, ΔS decrease with aluminium content, plateau slopes of the P-C-T curve increase with aluminium content
A visual acoustic high-pressure cell for the study of critical behavior of nonsimple mixtures
Aguiar-Ricardo, A.; Temtem, M.; Casimiro, T.; Ribeiro, N.
2004-10-01
A visual acoustic high-pressure cell was constructed for the determination of critical data of multicomponent mixtures. The cell was specially designed to include two piezoelectric transducers and two sapphire windows that make this cell well suited to investigate the critical behavior of mixtures, simultaneously using the acoustic technique and the direct visual inspection of the critical opalescence. Critical data obtained on the binary mixtures of CO2+CHF3 were used for comparison with values given in literature using the traditional methods. The acoustic results are in agreement with those obtained by the conventional methods, within the combined experimental errors. Comparison of visual and acoustic data enabled the evaluation of the applicability of the acoustic technique to study the critical behavior of multicomponent mixtures.
Thermodynamic analysis of fatty acid esterification for fatty acid alkyl esters production
International Nuclear Information System (INIS)
Voll, Fernando A.P.; Silva, Camila da; Rossi, Carla C.R.S.; Guirardello, Reginaldo; Castilhos, Fernanda de; Oliveira, J. Vladimir; Cardozo-Filho, Lucio
2011-01-01
The development of renewable energy source alternatives has become a planet need because of the unavoidable fossil fuel scarcity and for that reason biodiesel production has attracted growing interest over the last decade. The reaction yield for obtaining fatty acid alkyl esters varies significantly according to the operating conditions such as temperature and the feed reactants ratio and thus investigation of the thermodynamics involved in such reactional systems may afford important knowledge on the effects of process variables on biodiesel production. The present work reports a thermodynamic analysis of fatty acid esterification reaction at low pressure. For this purpose, Gibbs free energy minimization was employed with UNIFAC and modified Wilson thermodynamic models through a nonlinear programming model implementation. The methodology employed is shown to reproduce the most relevant investigations involving experimental studies and thermodynamic analysis.
Directory of Open Access Journals (Sweden)
Amin Dehyadegari
2017-05-01
Full Text Available It has been argued that charged Anti-de Sitter (AdS black holes have similar thermodynamic behavior as the Van der Waals fluid system, provided one treats the cosmological constant as a thermodynamic variable (pressure in an extended phase space. In this paper, we disclose the deep connection between charged AdS black holes and Van der Waals fluid system from an alternative point of view. We consider the mass of an AdS black hole as a function of square of the charge Q2 instead of the standard Q, i.e. M=M(S,Q2,P. We first justify such a change of view mathematically and then ask if a phase transition can occur as a function of Q2 for fixed P. Therefore, we write the equation of state as Q2=Q2(T,Ψ where Ψ (conjugate of Q2 is the inverse of the specific volume, Ψ=1/v. This allows us to complete the analogy of charged AdS black holes with Van der Waals fluid system and derive the phase transition as well as critical exponents of the system. We identify a thermodynamic instability in this new picture with real analogy to Van der Waals fluid with physically relevant Maxwell construction. We therefore study the critical behavior of isotherms in Q2–Ψ diagram and deduce all the critical exponents of the system and determine that the system exhibits a small–large black hole phase transition at the critical point (Tc,Qc2,Ψc. This alternative view is important as one can imagine such a change for a given single black hole i.e. acquiring charge which induces the phase transition. Finally, we disclose the microscopic properties of charged AdS black holes by using thermodynamic geometry. Interestingly, we find that scalar curvature has a gap between small and large black holes, and this gap becomes exceedingly large as one moves away from the critical point along the transition line. Therefore, we are able to attribute the sudden enlargement of the black hole to the strong repulsive nature of the internal constituents at the phase transition.
Thermodynamic properties and energy characteristics of water+1-propanol
Alhasov, A. B.; Bazaev, A. R.; Bazaev, E. A.; Osmanova, B. K.
2017-11-01
By using own precise experimental data on p,ρ,T,x- relations differential and integral thermodynamic properties of water+1-propanol homogeneous binary mixtures (0.2, 0.5, and 0.8 mole fractions of 1-propanol) were obtained in one phase (liquid, vapor) region, along coexistence curve phase, at critical and supercritical regions of parameters of state. These values were obtained in the regions of temperatures 373.15 - 673.15 K, densities 3 - 820 kg/m3 and pressures up to 50 MPa. It is found that shape of p,ρ,T,- dependences of water+1-propanol mixtures in investigated range of temperatures is the same with those of pure liquid, but the pressure of the mixture is higher than those of pure water or 1-propanol. The critical line of water+1-propanol binary mixtures as opposed to those of water+methanol and water+ethanol mixtures has convex shape. It is ascertained that using water+1-propanol mixture (0.2 mol.fraction of 1-propanol) instead of pure water allows to decrease lower limit of operating temperatures to 50 K, to increase effective coefficient of efficiency and partially unify thermal mechanical equipment of power plant. Our comparative energy analysis of cycles of steam-turbine plant on water and water+1- propanol mixtures, carried out at the same thermobaric conditionsand showed that thermal coefficient of efficiencyofcycle of steam-turbine plant onwater+1-propanol mixture (0.2 mol.fraction of 1-propanol) is higher than those of pure water.Thus and so we made a conclusion about usability of water+1-propanol mixture (0.2 mole fraction of 1-propanol) as a working substance of steam-turbine plant cycle.
Yang—Yang thermodynamics of one-dimensional Bose gases with anisotropic transversal confinement
International Nuclear Information System (INIS)
Hao Ya-Jiang; Yin Xiang-Guo
2011-01-01
By combining the thermodynamic Bethe ansatz and local density approximation, we investigate the Yang—Yang thermodynamics of interacting one-dimensional Bose gases with anisotropic transversal confinement. It is shown that with the increase of anisotropic parameter at low temperature, the Bose atoms are distributed over a wider region, while at high temperature the density distribution is not affected obviously. Both the temperature and transversal confinement can strengthen the local pressure of the Bose gases. (general)
International Nuclear Information System (INIS)
Pinto, Leandro F.; Segalen da Silva, Diogo Italo; Rosa da Silva, Fabiano; Ramos, Luiz P.; Ndiaye, Papa M.; Corazza, Marcos L.
2012-01-01
Highlights: → We measured phase behavior for the system involving {CO 2 + biodiesel + methanol}. → The saturation pressures were obtained using a variable-volume view cell. → The experimental data were modeled using PR-vdW2 and PR-WS equations of state. - Abstract: The main objective of this work was to investigate the high pressure phase behavior of the binary systems {CO 2 (1) + methanol(2)} and {CO 2 (1) + soybean methyl esters (biodiesel)(2)} and the ternary system {CO 2 (1) + biodiesel(2) + methanol(3)} were determined. Biodiesel was produced from soybean oil, purified, characterized and used in this work. The static synthetic method, using a variable-volume view cell, was employed to obtain the experimental data in the temperature range of (303.15 to 343.15) K and pressures up to 21 MPa. The mole fractions of carbon dioxide were varied according to the systems as follows: (0.2383 to 0.8666) for the binary system {CO 2 (1) + methanol(2)}; (0.4201 to 0.9931) for the binary system {CO 2 (1) + biodiesel(2)}; (0.4864 to 0.9767) for the ternary system {CO 2 (1) + biodiesel(2) + methanol(3)} with a biodiesel to methanol molar ratio of (1:3); and (0.3732 to 0.9630) for the system {CO 2 + biodiesel + methanol} with a biodiesel to methanol molar ratio of (8:1). For these systems, (vapor + liquid), (liquid + liquid), (vapor + liquid + liquid) transitions were observed. The phase equilibrium data obtained for the systems were modeled using the Peng-Robinson equation of state with the classical van der Waals (PR-vdW2) and Wong-Sandler (PR-WS) mixing rules. Both thermodynamic models were able to satisfactorily correlate the phase behavior of the systems investigated and the PR-WS presented the best performance.
Assessment of thermodynamic parameters of plasma shock wave
International Nuclear Information System (INIS)
Vasileva, O V; Isaev, Yu N; Budko, A A; Filkov, A I
2014-01-01
The work is devoted to the solution of the one-dimensional equation of hydraulic gas dynamics for the coaxial magneto plasma accelerator by means of Lax-Wendroff modified algorithm with optimum choice of the regularization parameter artificial viscosity. Replacement of the differential equations containing private derivatives is made by finite difference method. Optimum parameter of regularization artificial viscosity is added using the exact known decision of Soda problem. The developed algorithm of thermodynamic parameter calculation in a braking point is proved. Thermodynamic parameters of a shock wave in front of the plasma piston of the coaxial magneto plasma accelerator are calculated on the basis of the offered algorithm. Unstable high-frequency fluctuations are smoothed using modeling and that allows narrowing the ambiguity area. Results of calculation of gas dynamic parameters in a point of braking coincide with literary data. The chart 3 shows the dynamics of change of speed and thermodynamic parameters of a shock wave such as pressure, density and temperature just before the plasma piston
International Nuclear Information System (INIS)
Effenberg, Guenter; Ilyenko, Svitlana; Aldinger, Fritz; Bochvar, Nataliya; Cacciamani, Gabriele
2007-01-01
The present volume in the New Series of Landolt-Boernstein provides critically evaluated data on phase diagrams, crystallographic and thermodynamic data of ternary alloy systems. Reliable phase diagrams provide materials scientists and engineers with basic information important for fundamental research, development and optimization of materials. The often conflicting literature data have been critically evaluated by Materials Science International Team, MSIT registered , a team working together since many years, and with expertise in a broad range of methods, materials and applications. All evaluation reports published here have undergone a thorough review process in which the reviewers had access to all the original data. The data for each ternary system are provided in a standard format which includes text, tables and diagrams. The topics presented are literature data, binary systems, solid phases, pseudobinary systems, invariant equilibria, liquidus, solidus, and solvus surfaces, isothermal sections, temperature-composition sections, thermodynamics, materials properties and applications, and miscellanea. Finally, a detailed bibliography of all cited references is provided. In the present volume IV/11C selected non-ferrous-metal systems are considered, especially selected nuclear materials and engineering systems in this Part 4. (orig.)
International Nuclear Information System (INIS)
Badirkhan, Z.; Pastore, G.; Tosi, M.P.
1991-06-01
Calculations of the thermodynamic properties and pair distribution function of a one-component classical fluid of charged hard spheres in a uniform neutralizing background are reported and compared with Monte Carlo results of Hansen and Weis. Thermodynamic selfconsistence between the virial pressure and the fluctuations formula for the isothermal compressibility is enforced in the calculations by various alternative approaches. The role of thermodynamic selfconsistence is crucial to obtain a satisfactory quantitative description of this model fluid, in view of its applications in the theory of liquid metals and of dispersions of charged colloidal particles. (author). 23 refs, 4 figs, 3 tabs
Thermodynamic properties of 5-(1-adamantyl)tetrazole
Energy Technology Data Exchange (ETDEWEB)
Stepurko, Elena N.; Paulechka, Yauheni U.; Blokhin, Andrey V., E-mail: blokhin@bsu.by; Kabo, Gennady J.; Voitekhovich, Sergei V.; Lyakhov, Alexander S.; Kohut, Sviataslau V.; Kazarovets, Tatiana E.
2014-09-20
Highlights: • Heat capacity, enthalpy of formation, vapor pressure, and enthalpy of sublimation were measured for 5-(1-adamantyl)tetrazole. • Crystal structure of the compound was determined from the X-ray diffraction analysis. • Ideal-gas thermodynamic properties of 5-(1-adamantyl)tetrazole were calculated. - Abstract: Temperature dependence of the heat capacity of 5-(1-adamantyl)tetrazole was studied between (5 and 370) K in a vacuum adiabatic calorimeter. From obtained data the thermodynamic properties of the compound in the condensed state were evaluated over the range of (0–370) K. The crystal structure of 5-(1-adamantyl)tetrazole was determined from the X-ray diffraction analysis. The saturated vapor pressure for crystalline 5-(1-adamantyl)tetrazole in the temperature ranges from (394 to 419) K was measured by the Knudsen effusion method, and its enthalpy of sublimation was obtained using these results. The standard enthalpy of formation for crystalline 5-(1-adamantyl)tetrazole at 298.15 K was determined in a static bomb combustion calorimeter. From these data, the standard enthalpy of formation for gaseous 5-(1-adamantyl)tetrazole was evaluated. The enthalpy of formation calculated using quantum chemical methods is in an excellent agreement with the experimental value. The thermodynamic properties of 5-(1-adamantyl)tetrazole in the ideal-gas state were calculated in the temperature range from (0 to 1000) K. The calculated entropy of gaseous 5-(1-adamantyl)tetrazole is in a good agreement with the one obtained from the experimental data.
Thermodynamic properties of 5-(1-adamantyl)tetrazole
International Nuclear Information System (INIS)
Stepurko, Elena N.; Paulechka, Yauheni U.; Blokhin, Andrey V.; Kabo, Gennady J.; Voitekhovich, Sergei V.; Lyakhov, Alexander S.; Kohut, Sviataslau V.; Kazarovets, Tatiana E.
2014-01-01
Highlights: • Heat capacity, enthalpy of formation, vapor pressure, and enthalpy of sublimation were measured for 5-(1-adamantyl)tetrazole. • Crystal structure of the compound was determined from the X-ray diffraction analysis. • Ideal-gas thermodynamic properties of 5-(1-adamantyl)tetrazole were calculated. - Abstract: Temperature dependence of the heat capacity of 5-(1-adamantyl)tetrazole was studied between (5 and 370) K in a vacuum adiabatic calorimeter. From obtained data the thermodynamic properties of the compound in the condensed state were evaluated over the range of (0–370) K. The crystal structure of 5-(1-adamantyl)tetrazole was determined from the X-ray diffraction analysis. The saturated vapor pressure for crystalline 5-(1-adamantyl)tetrazole in the temperature ranges from (394 to 419) K was measured by the Knudsen effusion method, and its enthalpy of sublimation was obtained using these results. The standard enthalpy of formation for crystalline 5-(1-adamantyl)tetrazole at 298.15 K was determined in a static bomb combustion calorimeter. From these data, the standard enthalpy of formation for gaseous 5-(1-adamantyl)tetrazole was evaluated. The enthalpy of formation calculated using quantum chemical methods is in an excellent agreement with the experimental value. The thermodynamic properties of 5-(1-adamantyl)tetrazole in the ideal-gas state were calculated in the temperature range from (0 to 1000) K. The calculated entropy of gaseous 5-(1-adamantyl)tetrazole is in a good agreement with the one obtained from the experimental data
Tritium aging effect on thermodynamic functions of LaNi4.9Al0.1
International Nuclear Information System (INIS)
Xiong Yifu; Li Rong; Luo Deli
2001-01-01
The influence of tritium aging on thermodynamic function of LaNi 4.9 Al 0.1 is measured. The results show that plateau pressures and reversible hydrogen capacity decrease with aging time, thermodynamics parameters such as ΔH, ΔS and plateau slopes of the P-T curve increase with aging time, tritium heel formed after 1120 d tritium exposure
Sub-critical crack growth and clad integrity in a PWR reactor pressure vessel
International Nuclear Information System (INIS)
Tice, D.R.; Foreman, A.J.E.; Sharples, J.K.
1987-10-01
The possibility of in-service growth of sub-critical defects in a PWR reactor pressure vessel to a critical size which could result in vessel failure was addressed in both the 1976 and 1982 reports of the Light Water Reactor Study Group (LWRSG), under the Chairmanship of Dr W Marshall (now Lord Marshall). An addendum to this report was published by UKAEA in April 1987. The section of the addendum dealing with subcritical crack growth and the related issue of integrity of the stainless steel cladding on the inner vessel surface is reproduced in this report. This section of the LWRSG addendum provides a review of the current status of fatigue crack growth and environmentally assisted cracking research for pressure vessel steels in light water reactor environments, as well as a review of developments in crack growth assessment methods. The review concludes that the alternative assessment procedures now being developed give a more realistic prediction of in service crack growth than the ASME Section XI Appendix A fatigue crack growth curves. (author)
Thermodynamic modeling of the Ge-Ti system supported by key experiment
International Nuclear Information System (INIS)
Liu, Dandan; Yan, Huanli; Yuan, Xiaoming; Chung, Yoonsung; Du, Yong; Xu, Honghui; Liu, Libin; Nash, Philip
2011-01-01
Highlights: → All of the experimental phase diagram and thermodynamic data available for the Ge-Ti system have been critically evaluated. → The general feature of the Ge-Ti system and enthalpy of formation of Ti 5 Ge 3 have been checked via experiment. The annealed samples are characterized by X-ray diffraction, scanning electron microscope and differential thermal analysis. → An optimum thermodynamic data set for the Ge-Ti system was obtained. The comprehensive comparison shows that the calculated phase diagram and thermodynamic properties are in good agreement with the experimental data. - Abstract: A complete thermodynamic investigation of the Ge-Ti system was performed in this study. Seven samples were prepared by arc-melting the pure elements in order to check the literature data on phase diagram and enthalpy of formation of Ti 5 Ge 3 . The samples were annealed at certain temperatures for extended periods of time, and then quenched. Both the as-cast and annealed samples were examined by X-ray diffraction (XRD) analysis and scanning electron microscope (SEM) technology. The phase transformation temperatures were measured by differential thermal analysis (DTA). The measurement on enthalpy of formation for Ti 5 Ge 3 was performed using the Kleppa-type HTRC with the calorimeter temperature set at 1100 ± 2 o C. Based upon the literature data and current experimental results, the Ge-Ti system was critically assessed by means of CALPHAD approach. The calculated phase diagram and thermodynamic properties agree well with the literature data and the present experimental results.
Dynamics and thermodynamics of polymer glasses.
Cangialosi, D
2014-04-16
The fate of matter when decreasing the temperature at constant pressure is that of passing from gas to liquid and, subsequently, from liquid to crystal. However, a class of materials can exist in an amorphous phase below the melting temperature. On cooling such materials, a glass is formed; that is, a material with the rigidity of a solid but exhibiting no long-range order. The study of the thermodynamics and dynamics of glass-forming systems is the subject of continuous research. Within the wide variety of glass formers, an important sub-class is represented by glass forming polymers. The presence of chain connectivity and, in some cases, conformational disorder are unfavourable factors from the point of view of crystallization. Furthermore, many of them, such as amorphous thermoplastics, thermosets and rubbers, are widely employed in many applications. In this review, the peculiarities of the thermodynamics and dynamics of glass-forming polymers are discussed, with particular emphasis on those topics currently the subject of debate. In particular, the following aspects will be reviewed in the present work: (i) the connection between the pronounced slowing down of glassy dynamics on cooling towards the glass transition temperature (Tg) and the thermodynamics; and, (ii) the fate of the dynamics and thermodynamics below Tg. Both aspects are reviewed in light of the possible presence of a singularity at a finite temperature with diverging relaxation time and zero configurational entropy. In this context, the specificity of glass-forming polymers is emphasized.
Thermodynamic and relative approach to compute glass-forming
Indian Academy of Sciences (India)
This study deals with the evaluation of glass-forming ability (GFA) of oxides and is a critical reading of Sun and Rawson thermodynamic approach to quantify this aptitude. Both approaches are adequate but ambiguous regarding the behaviour of some oxides (tendency to amorphization or crystallization). Indeed, ZrO2 and ...
Thermodynamics of silicon nitridation - Effect of hydrogen
Shaw, N. J.; Zeleznik, F. J.
1982-01-01
Equilibrium compositions for the nitridization of Si were calculated to detect the effectiveness of H2 in removal of the oxide film and in increasing the concentration of SiO and reducing the proportions of O2. Gibbs free energy for the formation of SiN2O was computed above 1685 K, and at lower temperatures. The thermodynamic properties of SiN2O2 were then considered from 1000-3000 K, taking into account the known thermodynamic data for 39 molecular combinations of the Si, Ni, and O. The gases formed were assumed ideal mixtures with pure phase condensed species. The mole fractions were obtained for a system of SiO2 with each Si particle covered with a thin layer of SiO2 before nitridation, and a system in which the nitriding atmosphere had access to the Si. The presence of H2 was determined to enhance the removal of NiO2 in the first system, decrease the partial pressure of O2, increase the partial pressures of SiO, Si, H2O, NH3, and SiH4, while its effects were negligible in the Si system.
Müller, Ingo
1993-01-01
Physicists firmly believe that the differential equations of nature should be hyperbolic so as to exclude action at a distance; yet the equations of irreversible thermodynamics - those of Navier-Stokes and Fourier - are parabolic. This incompatibility between the expectation of physicists and the classical laws of thermodynamics has prompted the formulation of extended thermodynamics. After describing the motifs and early evolution of this new branch of irreversible thermodynamics, the authors apply the theory to mon-atomic gases, mixtures of gases, relativistic gases, and "gases" of phonons and photons. The discussion brings into perspective the various phenomena called second sound, such as heat propagation, propagation of shear stress and concentration, and the second sound in liquid helium. The formal mathematical structure of extended thermodynamics is exposed and the theory is shown to be fully compatible with the kinetic theory of gases. The study closes with the testing of extended thermodynamics thro...
International Nuclear Information System (INIS)
Muramatsu, Ken; Kondo, Yasuhiko; Uchida, Masaaki; Soda, Kunihisa
1989-01-01
Fission product (EP) release during a core concrete interaction (CCI) is an important factor of the uncertainty associated with a source term estimation for an LWR severe accident. An analysis was made on the CCI Chemical Thermodynamic Benchmark Exercise organized by OECD/NEA/CSNI Group of Experts on Source Terms (GREST) for investigating the uncertainty in thermodynamic modeling for CCI. The benchmark exercise was to calculate the equilibrium FP vapor pressure for given system of temperature, pressure, and debris composition. The benchmark consisted of two parts, A and B. Part A was a simplified problem intended to test the numerical techniques. In part B, the participants were requested to use their own best estimate thermodynamic data base to examine the variability of the results due to the difference in thermodynamic data base. JAERI participated in this benchmark exercise with use of the MPEC2 code. Chemical thermodynamic data base needed for analysis of Part B was taken from the VENESA code. This report describes the computer code used, inputs to the code, and results from the calculation by JAERI. The present calculation indicates that the FP vapor pressure depends strongly on temperature and Oxygen potential in core debris and the pattern of dependency may be different for different FP elements. (author)
Thermohydraulic feedbacks in self-pressurized reactor systems
International Nuclear Information System (INIS)
Fiebig, R.
1977-01-01
The impact on the dynamic behaviour of a self-pressurized reactor by the thermodynamic properties of the steam dome is investigated. For self-stabilization of the system the water of the primary circuit must be coupled thermodynamically to the steam in the steam dome, or alternatively the water in the reactor core must be subcooled sufficiently. Ways of thermodynamically coupling the water to the steam are heat conduction, boiling and condensation. A heat sink within the steam dome forces thermodynamic equilibrium between water and steam. This condition yields excellent self-control. Without heat sink thermal coupling is suspended at transients resulting in pressure rises. However, the reactor is still controlable as long as circuit and steam dome have direct contact. At the reactor of the NCS-80 a buffer volume of water separates primary circuit and steam volume. Stability is achieved by a heat sink in the steam dome and a shift of the core temperature into the subcooled domain effected by steam bubbles rising into the steam dome. (orig.) [de
Thermohydraulic feedbacks in self-pressurized reactor systems
International Nuclear Information System (INIS)
Fiebig, R.
1977-01-01
The impact on the dynamic behaviour of a self-pressurized reactor by the thermodynamic properties of the steam dome is investigated. For self-stabilization of the system the water of the primary circuit must be coupled thermodynamically to the steam in the steam dome, or alternatively the water in the reactor core must be subcooled sufficiently. Ways of thermodynamically coupling the water to the steam are heat conduction, boiling and condensation. A heat sink within the steam dome forces thermodynamic equilibrium between water and steam. This condition yields excellent self-control. Without heat sink thermal coupling is suspended at transients resulting in pressure rises. However, the reactor is still controllable as long as circuit and steam dome have direct contact. At the reactor of the NCS-80 a buffer volume of water separates primary circuit and steam volume. Stability is achieved by a heat sink in the steam dome and a shift of the core temperature into the subcooled domain effected by steam bubbles rising into the steam dome. (orig.) [de
International Nuclear Information System (INIS)
Rard, J.A.
1983-01-01
Chemical and thermodynamic data for Technetium (Tc) and some of its inorganic compounds and aqueous species are reviewed here. Major emphasis is given to systems with potential geochemical applications, especially the geochemistry of radioactive waste disposal. Compounds considered include oxides, hydroxides, hydrates oxides, halides, oxyhalides, double halides, and sulfides. The aqueous species considered include those in both noncomplexing media (pertechnetates, technetates, aquo-ions, and hydrolyzed cations) and complexing media (halides, sulfates, and phosphates). Thermodynamic values are recommended for specific compounds and aqueous ions when reliable experimental data are available. Where thermodynamic data are inadequate or unavailable, the chemistry is still discussed to provide information about what needs to be measured, and which chemistry needs to be clarified. A major application of these thermodynamic data will be for chemical equilibrium modeling and for construction of potential-pH diagrams for aqueous solutions. Unfortunately, the present lack of data precludes such calculations for complexing aqueous media. The situation is much better for noncomplexing aqueous media, but the chemistry and thermodynamics of cationic Tc(V) species and hydrolyzed Tc(III) species are poorly understood. 240 references, 6 tables
Thermodynamic stability of warped AdS3 black holes
International Nuclear Information System (INIS)
Birmingham, Danny; Mokhtari, Susan
2011-01-01
We study the thermodynamic stability of warped black holes in three-dimensional topologically massive gravity. The spacelike stretched black hole is parametrized by its mass and angular momentum. We determine the local and global stability properties in the canonical and grand canonical ensembles. The presence of a Hawking-Page type transition is established, and the critical temperature is determined. The thermodynamic metric of Ruppeiner is computed, and the curvature is shown to diverge in the extremal limit. The consequences of these results for the classical stability properties of warped black holes are discussed within the context of the correlated stability conjecture.
Thermodynamics, phase transition and quasinormal modes with Weyl corrections
Energy Technology Data Exchange (ETDEWEB)
Mahapatra, Subhash [The Institute of Mathematical Sciences,Chennai 600113 (India)
2016-04-21
We study charged black holes in D dimensional AdS space, in the presence of four derivative Weyl correction. We obtain the black hole solution perturbatively up to first as well as second order in the Weyl coupling, and show that first law of black hole thermodynamics is satisfied in all dimensions. We study its thermodynamic phase transition and then calculate the quasinormal frequencies of the massless scalar field perturbation. We find that, here too, the quasinormal frequencies capture the essence of black hole phase transition. Few subtleties near the second order critical point are discussed.
Energy Technology Data Exchange (ETDEWEB)
Zahlan, H., E-mail: hussamzahlan@gmail.com [Canadian Nuclear Laboratories, Chalk River, K0J 1J0 (Canada); Department of Mechanical Engineering, University of Ottawa, Ottawa, ON K1N 6N5 (Canada); Groeneveld, D. [Canadian Nuclear Laboratories, Chalk River, K0J 1J0 (Canada); Department of Mechanical Engineering, University of Ottawa, Ottawa, ON K1N 6N5 (Canada); Tavoularis, S. [Department of Mechanical Engineering, University of Ottawa, Ottawa, ON K1N 6N5 (Canada)
2015-08-15
Highlights: • We present and discuss results of thermal–hydraulic measurements in CO{sub 2} for the near critical and supercritical pressure region. • We report the full heat transfer and pressure drop database. - Abstract: An extensive experimental program of heat transfer measurements has been completed recently at the University of Ottawa's supercritical pressure test facility (SCUOL). Thermal–hydraulics tests were performed for vertical upflow of carbon dioxide in directly heated tubes with inner diameters of 8 and 22 mm, at high subcritical, near-critical and supercritical pressures. The test conditions, when converted to water-equivalent values, correspond to conditions of interest to current Super-Critical Water-Cooled Reactor designs, and include many measurements under conditions for which few data are available in the literature. These data significantly complement the existing experimental database and are being used for the derivation and validation of a new heat transfer prediction method in progress at the University of Ottawa. The same data are also suitable for the assessment of the accuracy of other heat transfer prediction methods and fluid-to-fluid scaling laws for near-critical and supercritical pressures. In addition, they permit further examination of previously suggested relationships describing the critical heat flux and post-dryout heat transfer coefficient at high subcritical pressures and the boundaries of the deteriorated/enhanced heat transfer regions for near-critical and supercritical pressures. The measurements reported in this paper cover several subcritical heat transfer modes, including single phase liquid heat transfer, nucleate boiling, critical heat flux, post-dryout heat transfer and superheated vapor heat transfer; they also cover several supercritical heat transfer modes, including heat transfer to liquid-like supercritical fluid and heat transfer to vapor-like supercritical fluid, which occurred in the
International Nuclear Information System (INIS)
Lee, Nam-Min; Lee, Byung-Hwan
2016-01-01
Highlights: • The values of critical micelle concentration of various pure and mixed surfactants are measured. • Thermodynamic parameters’ values are calculated to analyze the effects of head- and tail-groups on the micellization. • All the thermodynamic parameters’ values are decreasing with the increase of temperature. • The thermodynamic parameters’ values are depending severely on the chain length of alkyl group. - Abstract: The values of critical micelle concentration (CMC) for the micellization of various pure and mixed surfactants are determined by the UV–Vis spectrophotometric method. And the effects of temperature on the CMC values have been measured and thermodynamic parameters’ values are calculated to analyse the effects of head- and tail-groups on the micellization of surfactant molecules. The results show that the values of ΔG"o are negative and those of ΔS"o are positive for the micellization of all the surfactants within the measured temperature range. But the values of ΔH"o are positive or negative, depending on the kinds of surfactants. All these thermodynamic parameters’ values are decreasing together with the increase of temperature for all the surfactants. And these thermodynamic parameters’ values are depending severely on the chain length of alkyl group also as much as on the head-groups of surfactant molecules.
Estimation model for evaporative emissions from gasoline vehicles based on thermodynamics.
Hata, Hiroo; Yamada, Hiroyuki; Kokuryo, Kazuo; Okada, Megumi; Funakubo, Chikage; Tonokura, Kenichi
2018-03-15
In this study, we conducted seven-day diurnal breathing loss (DBL) tests on gasoline vehicles. We propose a model based on the theory of thermodynamics that can represent the experimental results of the current and previous studies. The experiments were performed using 14 physical parameters to determine the dependence of total emissions on temperature, fuel tank fill, and fuel vapor pressure. In most cases, total emissions after an apparent breakthrough were proportional to the difference between minimum and maximum environmental temperatures during the day, fuel tank empty space, and fuel vapor pressure. Volatile organic compounds (VOCs) were measured using a Gas Chromatography Mass Spectrometer and Flame Ionization Detector (GC-MS/FID) to determine the Ozone Formation Potential (OFP) of after-breakthrough gas emitted to the atmosphere. Using the experimental results, we constructed a thermodynamic model for estimating the amount of evaporative emissions after a fully saturated canister breakthrough occurred, and a comparison between the thermodynamic model and previous models was made. Finally, the total annual evaporative emissions and OFP in Japan were determined and compared by each model. Copyright © 2017 Elsevier B.V. All rights reserved.
Development of thermodynamic databases for geochemical calculations
Energy Technology Data Exchange (ETDEWEB)
Arthur, R.C. [Monitor Scientific, L.L.C., Denver, Colorado (United States); Sasamoto, Hiroshi; Shibata, Masahiro; Yui, Mikazu [Japan Nuclear Cycle Development Inst., Tokai, Ibaraki (Japan); Neyama, Atsushi [Computer Software Development Corp., Tokyo (Japan)
1999-09-01
Two thermodynamic databases for geochemical calculations supporting research and development on geological disposal concepts for high level radioactive waste are described in this report. One, SPRONS.JNC, is compatible with thermodynamic relations comprising the SUPCRT model and software, which permits calculation of the standard molal and partial molal thermodynamic properties of minerals, gases, aqueous species and reactions from 1 to 5000 bars and 0 to 1000degC. This database includes standard molal Gibbs free energies and enthalpies of formation, standard molal entropies and volumes, and Maier-Kelly heat capacity coefficients at the reference pressure (1 bar) and temperature (25degC) for 195 minerals and 16 gases. It also includes standard partial molal Gibbs free energies and enthalpies of formation, standard partial molal entropies, and Helgeson, Kirkham and Flowers (HKF) equation-of-state coefficients at the reference pressure and temperature for 1147 inorganic and organic aqueous ions and complexes. SPRONS.JNC extends similar databases described elsewhere by incorporating new and revised data published in the peer-reviewed literature since 1991. The other database, PHREEQE.JNC, is compatible with the PHREEQE series of geochemical modeling codes. It includes equilibrium constants at 25degC and l bar for mineral-dissolution, gas-solubility, aqueous-association and oxidation-reduction reactions. Reaction enthalpies, or coefficients in an empirical log K(T) function, are also included in this database, which permits calculation of equilibrium constants between 0 and 100degC at 1 bar. All equilibrium constants, reaction enthalpies, and log K(T) coefficients in PHREEQE.JNC are calculated using SUPCRT and SPRONS.JNC, which ensures that these two databases are mutually consistent. They are also internally consistent insofar as all the data are compatible with basic thermodynamic definitions and functional relations in the SUPCRT model, and because primary
Development of thermodynamic databases for geochemical calculations
International Nuclear Information System (INIS)
Arthur, R.C.; Sasamoto, Hiroshi; Shibata, Masahiro; Yui, Mikazu; Neyama, Atsushi
1999-09-01
Two thermodynamic databases for geochemical calculations supporting research and development on geological disposal concepts for high level radioactive waste are described in this report. One, SPRONS.JNC, is compatible with thermodynamic relations comprising the SUPCRT model and software, which permits calculation of the standard molal and partial molal thermodynamic properties of minerals, gases, aqueous species and reactions from 1 to 5000 bars and 0 to 1000degC. This database includes standard molal Gibbs free energies and enthalpies of formation, standard molal entropies and volumes, and Maier-Kelly heat capacity coefficients at the reference pressure (1 bar) and temperature (25degC) for 195 minerals and 16 gases. It also includes standard partial molal Gibbs free energies and enthalpies of formation, standard partial molal entropies, and Helgeson, Kirkham and Flowers (HKF) equation-of-state coefficients at the reference pressure and temperature for 1147 inorganic and organic aqueous ions and complexes. SPRONS.JNC extends similar databases described elsewhere by incorporating new and revised data published in the peer-reviewed literature since 1991. The other database, PHREEQE.JNC, is compatible with the PHREEQE series of geochemical modeling codes. It includes equilibrium constants at 25degC and l bar for mineral-dissolution, gas-solubility, aqueous-association and oxidation-reduction reactions. Reaction enthalpies, or coefficients in an empirical log K(T) function, are also included in this database, which permits calculation of equilibrium constants between 0 and 100degC at 1 bar. All equilibrium constants, reaction enthalpies, and log K(T) coefficients in PHREEQE.JNC are calculated using SUPCRT and SPRONS.JNC, which ensures that these two databases are mutually consistent. They are also internally consistent insofar as all the data are compatible with basic thermodynamic definitions and functional relations in the SUPCRT model, and because primary
Tarnacka, M; Madejczyk, O; Adrjanowicz, K; Pionteck, J; Kaminska, E; Kamiński, K; Paluch, M
2015-06-14
Pressure-Volume-Temperature (PVT) measurements and broadband dielectric spectroscopy were carried out to investigate molecular dynamics and to test the validity of thermodynamic scaling of two homologous compounds of pharmaceutical activity: itraconazole and ketoconazole in the wide range of thermodynamic conditions. The pressure coefficients of the glass transition temperature (dT(g)/dp) for itraconazole and ketoconazole were determined to be equal to 183 and 228 K/GPa, respectively. However, for itraconazole, the additional transition to the nematic phase was observed and characterized by the pressure coefficient dT(n)/dp = 258 K/GPa. From PVT and dielectric data, we obtained that the liquid-nematic phase transition is governed by the relaxation time since it occurred at constant τ(α) = 10(-5) s. Furthermore, we plotted the obtained relaxation times as a function of T(-1)v(-γ), which has revealed that the validity of thermodynamic scaling with the γ exponent equals to 3.69 ± 0.04 and 3.64 ± 0.03 for itraconazole and ketoconazole, respectively. Further analysis of the scaling parameter in itraconazole revealed that it unexpectedly decreases with increasing relaxation time, which resulted in dramatic change of the shape of the thermodynamic scaling master curve. While in the case of ketoconazole, it remained the same within entire range of data (within experimental uncertainty). We suppose that in case of itraconazole, this peculiar behavior is related to the liquid crystals' properties of itraconazole molecule.
Energy Technology Data Exchange (ETDEWEB)
Tarnacka, M., E-mail: mtarnacka@us.edu.pl; Madejczyk, O.; Kamiński, K.; Paluch, M. [Institute of Physics, University of Silesia, ul. Uniwersytecka 4, 40-007 Katowice (Poland); Silesian Center of Education and Interdisciplinary Research, University of Silesia, ul. 75 Pulku Piechoty 1A, 41-500 Chorzow (Poland); Adrjanowicz, K. [NanoBioMedical Centre, ul. Umultowska 85, 61-614 Poznan (Poland); Pionteck, J. [Leibniz Institute of Polymer Research Dresden, Hohe Strasse 6, D-01069 Dresden (Germany); Kaminska, E. [Department of Pharmacognosy and Phytochemistry, School of Pharmacy and Division of Laboratory Medicine in Sosnowiec, Medical University of Silesia, ul. Jagiellonska 4, 41-200 Sosnowiec (Poland)
2015-06-14
Pressure-Volume-Temperature (PVT) measurements and broadband dielectric spectroscopy were carried out to investigate molecular dynamics and to test the validity of thermodynamic scaling of two homologous compounds of pharmaceutical activity: itraconazole and ketoconazole in the wide range of thermodynamic conditions. The pressure coefficients of the glass transition temperature (dT{sub g}/dp) for itraconazole and ketoconazole were determined to be equal to 183 and 228 K/GPa, respectively. However, for itraconazole, the additional transition to the nematic phase was observed and characterized by the pressure coefficient dT{sub n}/dp = 258 K/GPa. From PVT and dielectric data, we obtained that the liquid-nematic phase transition is governed by the relaxation time since it occurred at constant τ {sub α} = 10{sup −5} s. Furthermore, we plotted the obtained relaxation times as a function of T{sup −1}v{sup −γ}, which has revealed that the validity of thermodynamic scaling with the γ exponent equals to 3.69 ± 0.04 and 3.64 ± 0.03 for itraconazole and ketoconazole, respectively. Further analysis of the scaling parameter in itraconazole revealed that it unexpectedly decreases with increasing relaxation time, which resulted in dramatic change of the shape of the thermodynamic scaling master curve. While in the case of ketoconazole, it remained the same within entire range of data (within experimental uncertainty). We suppose that in case of itraconazole, this peculiar behavior is related to the liquid crystals’ properties of itraconazole molecule.
Preliminary thermodynamic study for an efficient turbo-blower external combustion Rankine cycle
Romero Gómez, Manuel; Romero Gómez, Javier; Ferreiro Garcia, Ramón; Baaliña Insua, Álvaro
2014-08-01
This research paper presents a preliminary thermodynamic study of an innovative power plant operating under a Rankine cycle fed by an external combustion system with turbo-blower (TB). The power plant comprises an external combustion system for natural gas, where the combustion gases yield their thermal energy, through a heat exchanger, to a carbon dioxide Rankine cycle operating under supercritical conditions and with quasi-critical condensation. The TB exploits the energy from the pressurised exhaust gases for compressing the combustion air. The study is focused on the comparison of the combustion system's conventional technology with that of the proposed. An energy analysis is carried out and the effect of the flue gas pressure on the efficiency and on the heat transfer in the heat exchanger is studied. The coupling of the TB results in an increase in efficiency and of the convection coefficient of the flue gas with pressure, favouring a reduced volume of the heat exchanger. The proposed innovative system achieves increases in efficiency of around 12 % as well as a decrease in the heat exchanger volume of 3/5 compared with the conventional technology without TB.
Thermodynamic assessment of the Pb-Sr system
Directory of Open Access Journals (Sweden)
Zhang H.
2017-01-01
Full Text Available The Pb-Sr system has been critically reviewed and modeled by means of the CALPHAD (CALculation of PHAse Diagrams approach. It contains seven stoichiometric compounds, i.e. SrPb3, Sr3Pb5, Sr2Pb3, SrPb, Sr5Pb4, Sr5Pb3 and Sr2Pb, in which the SrPb3 and Sr2Pb phases melt congruently, and the other five phases form via peritectic reactions. The enthalpies of formation for the intermetallic compounds at 0 K are provided by first-principles calculations. The liquid, fcc and bcc phases are modeled as substitutional solution phases. Both Redlich-Kister and exponential polynomials are used to describe the excess Gibbs energy of the liquid. Two sets of self-consistent thermodynamic parameters are obtained by considering reliable experimental data and the computed enthalpies of formation. Comprehensive comparisons between the calculated and measured phase diagram and thermodynamic data show that the experimental information is satisfactorily accounted for by the present thermodynamic description.
Wang, Han; Nakamura, Haruki; Fukuda, Ikuo
2016-03-21
We performed extensive and strict tests for the reliability of the zero-multipole (summation) method (ZMM), which is a method for estimating the electrostatic interactions among charged particles in a classical physical system, by investigating a set of various physical quantities. This set covers a broad range of water properties, including the thermodynamic properties (pressure, excess chemical potential, constant volume/pressure heat capacity, isothermal compressibility, and thermal expansion coefficient), dielectric properties (dielectric constant and Kirkwood-G factor), dynamical properties (diffusion constant and viscosity), and the structural property (radial distribution function). We selected a bulk water system, the most important solvent, and applied the widely used TIP3P model to this test. In result, the ZMM works well for almost all cases, compared with the smooth particle mesh Ewald (SPME) method that was carefully optimized. In particular, at cut-off radius of 1.2 nm, the recommended choices of ZMM parameters for the TIP3P system are α ≤ 1 nm(-1) for the splitting parameter and l = 2 or l = 3 for the order of the multipole moment. We discussed the origin of the deviations of the ZMM and found that they are intimately related to the deviations of the equilibrated densities between the ZMM and SPME, while the magnitude of the density deviations is very small.
Energy Technology Data Exchange (ETDEWEB)
Wang, Han, E-mail: wang-han@iapcm.ac.cn [CAEP Software Center for High Performance Numerical Simulation, Huayuan Road 6, 100088 Beijing, China and Zuse Institute Berlin (ZIB), Berlin (Germany); Nakamura, Haruki [Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871 (Japan); Fukuda, Ikuo, E-mail: ifukuda@protein.osaka-u.ac.jp [Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871 (Japan); RIKEN (The Institute of Physical and Chemical Research), 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan)
2016-03-21
We performed extensive and strict tests for the reliability of the zero-multipole (summation) method (ZMM), which is a method for estimating the electrostatic interactions among charged particles in a classical physical system, by investigating a set of various physical quantities. This set covers a broad range of water properties, including the thermodynamic properties (pressure, excess chemical potential, constant volume/pressure heat capacity, isothermal compressibility, and thermal expansion coefficient), dielectric properties (dielectric constant and Kirkwood-G factor), dynamical properties (diffusion constant and viscosity), and the structural property (radial distribution function). We selected a bulk water system, the most important solvent, and applied the widely used TIP3P model to this test. In result, the ZMM works well for almost all cases, compared with the smooth particle mesh Ewald (SPME) method that was carefully optimized. In particular, at cut-off radius of 1.2 nm, the recommended choices of ZMM parameters for the TIP3P system are α ≤ 1 nm{sup −1} for the splitting parameter and l = 2 or l = 3 for the order of the multipole moment. We discussed the origin of the deviations of the ZMM and found that they are intimately related to the deviations of the equilibrated densities between the ZMM and SPME, while the magnitude of the density deviations is very small.
Liang, Sai; Qu, Shen; Xu, Ming
2016-02-02
To develop industry-specific policies for mitigating environmental pressures, previous studies primarily focus on identifying sectors that directly generate large amounts of environmental pressures (a.k.a. production-based method) or indirectly drive large amounts of environmental pressures through supply chains (e.g., consumption-based method). In addition to those sectors as important environmental pressure producers or drivers, there exist sectors that are also important to environmental pressure mitigation as transmission centers. Economy-wide environmental pressure mitigation might be achieved by improving production efficiency of these key transmission sectors, that is, using less upstream inputs to produce unitary output. We develop a betweenness-based method to measure the importance of transmission sectors, borrowing the betweenness concept from network analysis. We quantify the betweenness of sectors by examining supply chain paths extracted from structural path analysis that pass through a particular sector. We take China as an example and find that those critical transmission sectors identified by betweenness-based method are not always identifiable by existing methods. This indicates that betweenness-based method can provide additional insights that cannot be obtained with existing methods on the roles individual sectors play in generating economy-wide environmental pressures. Betweenness-based method proposed here can therefore complement existing methods for guiding sector-level environmental pressure mitigation strategies.
Glass formability in medium-sized molecular systems/pharmaceuticals. I. Thermodynamics vs. kinetics
Energy Technology Data Exchange (ETDEWEB)
Tu, Wenkang; Li, Xiangqian; Chen, Zeming; Liu, Ying Dan; Wang, Li-Min, E-mail: simone.capaccioli@unipi.it, E-mail: Limin-Wang@ysu.edu.cn [State Key Lab of Metastable Materials Science and Technology, and College of Materials Science and Engineering, Yanshan University, Qinhuangdao, Hebei 066004 (China); Labardi, Massimiliano [CNR-IPCF, Sede Secondaria Pisa, Largo Pontecorvo 3, I-56127 Pisa (Italy); Capaccioli, Simone, E-mail: simone.capaccioli@unipi.it, E-mail: Limin-Wang@ysu.edu.cn [CNR-IPCF, Sede Secondaria Pisa, Largo Pontecorvo 3, I-56127 Pisa (Italy); Department of Physics, Pisa University, Largo Bruno Pontecorvo 3, I-56127 Pisa (Italy); Paluch, M. [Institute of Physics, University of Silesia, Uniwersytecka 4, 40-007 Katowice (Poland)
2016-05-07
Scrutinizing critical thermodynamic and kinetic factors for glass formation and the glass stability of materials would benefit the screening of the glass formers for the industry of glassy materials. The present work aims at elucidating the factors that contribute to the glass formation by investigating medium-sized molecules of pharmaceuticals. Glass transition related thermodynamics and kinetics are performed on the pharmaceuticals using calorimetric, dielectric, and viscosity measurements. The characteristic thermodynamic and kinetic parameters of glass transition are found to reproduce the relations established for small-molecule glass formers. The systematic comparison of the thermodynamic and kinetic contributions to glass formation reveals that the melting-point viscosity is the crucial quantity for the glass formation. Of more interest is the finding of a rough correlation between the melting-point viscosity and the entropy of fusion normalized by the number of beads of the pharmaceuticals, suggesting the thermodynamics can partly manifest its contribution to glass formation via kinetics.
Glass formability in medium-sized molecular systems/pharmaceuticals. I. Thermodynamics vs. kinetics.
Tu, Wenkang; Li, Xiangqian; Chen, Zeming; Liu, Ying Dan; Labardi, Massimiliano; Capaccioli, Simone; Paluch, M; Wang, Li-Min
2016-05-07
Scrutinizing critical thermodynamic and kinetic factors for glass formation and the glass stability of materials would benefit the screening of the glass formers for the industry of glassy materials. The present work aims at elucidating the factors that contribute to the glass formation by investigating medium-sized molecules of pharmaceuticals. Glass transition related thermodynamics and kinetics are performed on the pharmaceuticals using calorimetric, dielectric, and viscosity measurements. The characteristic thermodynamic and kinetic parameters of glass transition are found to reproduce the relations established for small-molecule glass formers. The systematic comparison of the thermodynamic and kinetic contributions to glass formation reveals that the melting-point viscosity is the crucial quantity for the glass formation. Of more interest is the finding of a rough correlation between the melting-point viscosity and the entropy of fusion normalized by the number of beads of the pharmaceuticals, suggesting the thermodynamics can partly manifest its contribution to glass formation via kinetics.
Condensation and critical exponents of an ideal non-Abelian gas
Talaei, Zahra; Mirza, Behrouz; Mohammadzadeh, Hosein
2017-11-01
We investigate an ideal gas obeying non-Abelian statistics and derive the expressions for some thermodynamic quantities. It is found that thermodynamic quantities are finite at the condensation point where their derivatives diverge and, near this point, they behave as \\vert T-Tc\\vert^{-ρ} in which Tc denotes the condensation temperature and ρ is a critical exponent. The critical exponents related to the heat capacity and compressibility are obtained by fitting numerical results and others are obtained using the scaling law hypothesis for a three-dimensional non-Abelian ideal gas. This set of critical exponents introduces a new universality class.
Riemannian geometry of thermodynamics and systems with repulsive power-law interactions.
Ruppeiner, George
2005-07-01
A Riemannian geometric theory of thermodynamics based on the postulate that the curvature scalar R is proportional to the inverse free energy density is used to investigate three-dimensional fluid systems of identical classical point particles interacting with each other via a power-law potential energy gamma r(-alpha) . Such systems are useful in modeling melting transitions. The limit alpha-->infinity corresponds to the hard sphere gas. A thermodynamic limit exists only for short-range (alpha>3) and repulsive (gamma>0) interactions. The geometric theory solutions for given alpha>3 , gamma>0 , and any constant temperature T have the following properties: (1) the thermodynamics follows from a single function b (rho T(-3/alpha) ) , where rho is the density; (2) all solutions are equivalent up to a single scaling constant for rho T(-3/alpha) , related to gamma via the virial theorem; (3) at low density, solutions correspond to the ideal gas; (4) at high density there are solutions with pressure and energy depending on density as expected from solid state physics, though not with a Dulong-Petit heat capacity limit; (5) for 33.7913 a phase transition is required to go between these regimes; (7) for any alpha>3 we may include a first-order phase transition, which is expected from computer simulations; and (8) if alpha-->infinity, the density approaches a finite value as the pressure increases to infinity, with the pressure diverging logarithmically in the density difference.
[Differentiation between moisture lesions and pressure ulcers using photographs in a critical area].
Valls-Matarín, Josefa; Del Cotillo-Fuente, Mercedes; Pujol-Vila, María; Ribal-Prior, Rosa; Sandalinas-Mulero, Inmaculada
2016-01-01
To identify difficulties for nurses in differentiating between moisture lesions and pressure ulcers, proper classification of pressure ulcers to assess the adequate classification of the Grupo Nacional para el Estudio y Asesoramiento de Úlceras por Presión y Heridas Crónicas (GNEAUPP) and the degree of agreement in the correct assessment by type and category of injury. Cross-sectional study in a critical area during 2014. All nurses who agreed to participate were included. They performed a questionnaire with 14 photographs validated by experts of moisture lesions or pressure ulcers in the sacral area and buttocks, with 6 possible answers: Pressure ulcer category I, II, III, IV, moisture lesions and unknown. Demographics and knowledge of the classification system of the pressure ulcers were collected according to GNEAUPP. It involved 98% of the population (n=56); 98.2% knew the classification system of the GNEAUPP; 35.2% of moisture lesions were considered as pressure ulcers, most of them as a category II (18.9%). The 14.8% of the pressure ulcers photographs were identified as moisture lesions and 16.1% were classified in another category. The agreement between nurses earned a global Kappa index of .38 (95% CI: .29-.57). There are difficulties differentiating between pressure ulcers and moisture lesions, especially within initial categories. Nurses have the perception they know the pressure ulcers classification, but they do not classify them correctly. The degree of concordance in the diagnosis of skin lesions was low. Copyright © 2016 Elsevier España, S.L.U. All rights reserved.
Thermodynamics of Phantom Energy Accreting onto a Black Hole in Einstein—Power—Maxwell Gravity
International Nuclear Information System (INIS)
Abbas, G.; Ramzan, R. M.
2013-01-01
We investigate the phantom energy accretion onto a 3D black hole formulated in the Einstein—Power—Maxwell theory, and present the conditions for critical accretion of phantom energy onto the black hole. Further, we discuss the thermodynamics of phantom energy accreting onto the black hole and find that the first law of thermodynamics is easily satisfied while the second law and the generalized second law of thermodynamics remain invalid and conditionally valid, respectively. The results for the Banados—Teitelboim—Zanelli black hole can be recovered by taking Maxwellian contribution equal to zero
Thermodynamic treatment of nonphysical systems: formalism and an example (single-lane traffic)
International Nuclear Information System (INIS)
Reiss, H.; Hammerich, A.D.; Montroll, E.W.
1986-01-01
An effort is made to introduce thermodynamic and statistical thermodynamic methods into the treatment of nonphysical (e.g., social, economic, etc.) systems. Emphasis is placed on the use of the entire thermodynamic framework, not merely entropy. Entropy arises naturally, related in a simple manner to other measurables, but does not occupy a primary position in the theory. However, the maximum entropy formalism is a convenient procedure for deriving the thermodynamic analog framework in which undetermined multipliers are thermodynamic-like variables which summarize the collective behavior of the system. The authors discuss the analysis of Levine and his coworkers showing that the maximum entropy formalism is the unique algorithm for achieving consistent inference of probabilities. The thermodynamic-like formalism for treating a single lane of vehicular traffic is developed and applied to traffic in which the interaction between cars is chosen to be a particular form of the ''follow-the-leader'' type. The equation of state of the traffic, the distributions of velocity and headway, and the various thermodynamic-like parameters, e.g., temperature (collective sensitivity), pressure, etc. are determined for the example of the Holland Tunnel. Nearest-neighbor and pair correlation functions for the vehicles are also determined. Interesting and suggestive results are obtained
Thermodynamic and elastic properties of hexagonal ZnO under high temperature
International Nuclear Information System (INIS)
Wang, Feng; Wu, Jinghe; Xia, Chuanhui; Hu, Chenghua; Hu, Chunlian; Zhou, Ping; Shi, Lingna; Ji, Yanling; Zheng, Zhou; Liu, Xiankun
2014-01-01
Highlights: • A new method is applied to predict crystal constants of hexagonal crystal under high temperature. • Elastic properties of ZnO under high temperature are obtained exactly. • Thermodynamic properties of ZnO under high temperature are attained too. - Abstract: Studies on thermodynamic and elastic properties of hexagonal ZnO (wurtzite structure) under high temperature have not been reported usually from no matter experimental or theoretic methods. In this work, we study these properties by ab-initio together with quasi-harmonic Debye model. The value of C v tends to the Petit and Dulong limit at high temperature under any pressure, 49.73 J/mol K. And C v is greatly limited by pressure at intermediate temperatures. Nevertheless, the limit effect on C v caused by pressure is not obvious under low as well as very high temperature. The thermal expansions along a or c axis are almost same under temperature, which increase with temperature like a parabola. C 11 , C 33 , C 12 and C 13 decrease with temperature a little, which means that mechanics properties are weakened respectively
Analysis on ventilation pressure of fire area in longitudinal ventilation of underground tunnel
Li, Jiaxin; Li, Yanfeng; Feng, Xiao; Li, Junmei
2018-03-01
In order to solve the problem of ventilation pressure loss in the fire area under the fire condition, the wind pressure loss model of the fire area is established based on the thermodynamic equilibrium relation. The semi-empirical calculation formula is obtained by using the model experiment and CFD simulation. The validity of the formula is verified. The results show that the ventilation pressure loss in the fire zone is proportional to the convective heat release rate at the critical velocity, which is inversely proportional to the upstream ventilation velocity and the tunnel cross-sectional area. The proposed formula is consistent with the law of the tunnel fire test fitting formula that results are close, in contrast, the advantage lies in a clear theoretical basis and ventilation velocity values. The resistance of road tunnel ventilation system is calculated accurately and reliably, and then an effective emergency ventilation operation program is developed. It is necessary to consider the fire zone ventilation pressure loss. The proposed ventilation pressure loss formula can be used for design calculation after thorough verification.
Thermodynamic data for biomass conversion and waste incineration
Energy Technology Data Exchange (ETDEWEB)
Domalski, E.S.; Jobe, T.L. Jr; Milne, T.A.
1986-09-01
The general purpose of this collection of thermodynamic data of selected materials is to make property information available to the engineering community on chemical mixtures, polymers, composite materials, solid wastes, biomass, and materials not easily identifiable by a single stoichiometric formula. More than 700 materials have been compiled covering properties such as specific heat, gross heat of combustion, heat of fusion, heat of vaporization, and vapor pressure. The information was obtained from the master files of the NBS Chemical Thermodynamics Data Center, the annual issues of the Bulletin of Chemical Thermodynamics, intermittent examinations of the Chemical Abstracts subject indexes, individual articles by various authors, and other general reference sources. The compilation is organized into several broad categories; materials are listed alphabetically within each category. For each material, the physical state, information as to the composition or character of the material, the kind of thermodynamic property reported, the specific property values for the material, and citations to the reference list are given. In addition, appendix A gives an empirical formula that allows heats of combustion of carbonaceous materials to be predicted with surprising accuracy when the elemental composition is known. A spread sheet illustrates this predictability with examples from this report and elsewhere. Appendix B lists some reports containing heats of combustion not included in this publication. Appendix C contains symbols, units, conversion factors, and atomic weights used in evaluating and compiling the thermodynamic data.
Thermodynamic phase transition in the rainbow Schwarzschild black hole
International Nuclear Information System (INIS)
Gim, Yongwan; Kim, Wontae
2014-01-01
We study the thermodynamic phase transition in the rainbow Schwarzschild black hole where the metric depends on the energy of the test particle. Identifying the black hole temperature with the energy from the modified dispersion relation, we obtain the modified entropy and thermodynamic energy along with the modified local temperature in the cavity to provide well defined black hole states. It is found that apart from the conventional critical temperature related to Hawking-Page phase transition there appears an additional critical temperature which is of relevance to the existence of a locally stable tiny black hole; however, the off-shell free energy tells us that this black hole should eventually tunnel into the stable large black hole. Finally, we discuss the reason why the temperature near the horizon is finite in the rainbow black hole by employing the running gravitational coupling constant, whereas it is divergent near the horizon in the ordinary Schwarzschild black hole
A Thermodynamic Model for the Fuel of a Molten Salt Actinide Burner
Energy Technology Data Exchange (ETDEWEB)
Benes, Ondrej [Institute of Chemical Technology, Technicka 5, 16603 Prague (Czech Republic); European Commission - Joint Research Centre - Institute for Transuranium Elements, P.O. BOX 2340, 76125 Karlsruhe (Germany)
2008-07-01
In this study the importance of the thermodynamic description of a multi-component system when optimizing the fuel choice for a molten salt reactor is demonstrated. It is shown on the MF-PuF{sub 3} (M=Li,Na,K,Rb) system, one of the fuel alternatives, how properties such as vapour pressure or the solubility of the actinides in the alkali halide matrix can be obtained. Moreover it is shown that much bigger PuF{sub 3} solubility is achieved in the matrix containing only alkali halides than in a matrix that contains some concentrations of BeF{sub 2}. In order to obtain full thermodynamic description of the MF-PuF{sub 3} (M=Li,Na,K,Rb,Cs) system all the binary phase diagrams must be assessed. This is done according to the CALPHAD method including the critical review of all available data followed by an interactive optimization of the phase diagram to achieve the best possible agreement between the measurement and the calculation. A novel approach of obtaining the excess enthalpies of the (Rb,Cs)F solid solution by Ab initio has been used and the results are compared to the experimentally determined phase diagram measured in this study as well. For the measurement of the phase diagrams of the volatile fluoride salts special encapsulation technique has been developed. (authors)
Recommended sublimation pressure and enthalpy of benzene
Czech Academy of Sciences Publication Activity Database
Růžička, K.; Fulem, Michal; Červinka, C.
2014-01-01
Roč. 68, Jan (2014), s. 40-47 ISSN 0021-9614 Institutional support: RVO:68378271 Keywords : benzene * vapor pressure * heat capacity * ideal - gas thermodynamic properties * sublimation enthalpy * recommended vapor pressure Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.679, year: 2014
Cavitation erosion of silver plated coating at different temperatures and pressures
Energy Technology Data Exchange (ETDEWEB)
Hattori, Shuji; Motoi, Yoshihiro [Graduate School of Engineering, University of Fukui, 3-9-1 Bunkyo, Fuku-shi, Fukui 910-8507 (Japan); Kikuta, Kengo; Tomaru, Hiroshi [IHI Corperation, TOYOSU IHI BUILDING, 1-1, Toyosu 3-chome, Koto-ku, Tokyo 1358710 (Japan)
2014-04-11
Cavitation often occurs in inducer pumps used for space rockets. Silver plated coating on the inducer liner faces the damage of cavitation. Therefore, it is important to study about the cavitation erosion resistance for silver plated coating at several operating conditions in the inducer pumps. In this study, the cavitation erosion tests were carried for silver plated coating in deionized water and ethanol at several liquid temperatures (273K–400K) and pressures (0.10MPa–0.48MPa). The mass loss rate is evaluated in terms of thermodynamic parameter Σ proposed by Brennen [9], suppression pressure p–p{sub v} (p{sub v}: saturated vapor pressure) and acoustic impedance ρc (ρ: density and c: sound speed). Cavitation bubble behaviors depending on the thermodynamic effect and the liquid type were observed by high speed video camera. The mass loss rate is formulated by thermodynamic parameter Σ, suppression pressure p–p{sub v} and acoustic impedance ρc.
Thermodynamic properties of 4-tert-butyl-diphenyl oxide
International Nuclear Information System (INIS)
Druzhinina, A.I.; Pimenova, S.M.; Tarazanov, S.V.; Nesterova, T.N.; Varushchenko, R.M.
2015-01-01
Highlights: • The sample of the 4-tert-butyl-diphenyl oxide was synthesized and purified. • Heat capacities, energy of combustion, saturation vapor pressures were measured. • The temperature, the enthalpy and the entropy of fusion were determined. • The enthalpy of sublimation at T = 298.15 K was derived. • The main thermodynamic functions and functions of formation were computed. - Abstract: The main thermodynamic functions (changes of the entropy, enthalpy, and Gibbs free energy) and functions of formation at T = 298.15 K of 4-tert-butyl-diphenyl oxide in condensed and ideal gas states were computed on the basis of experimental results obtained. The heat capacities of 4-tert-butyl-diphenyl oxide was measured by vacuum adiabatic calorimetry over the temperature range (8 to 371) K. The temperature, the enthalpy and the entropy of fusion were determined. The energy of combustion of the sample was determined by static-bomb combustion calorimetry. The saturation vapor pressures of the substance were measured by dynamic transpiration method over the temperature and pressure intervals (298 to 325) K and (0.05 to 1.2) Pa. The enthalpy of sublimation at T = 298.15 K was derived. The contribution of O-(2C b ) group (where C b is the carbon atom in a benzene ring) into the absolute entropies of diphenyl oxide derivatives was assessed
Thermodynamic and Mechanical Analysis of a Thermomagnetic Rotary Engine
International Nuclear Information System (INIS)
Fajar, D M; Khotimah, S N; Khairurrijal
2016-01-01
A heat engine in magnetic system had three thermodynamic coordinates: magnetic intensity ℋ, total magnetization ℳ, and temperature T, where the first two of them are respectively analogous to that of gaseous system: pressure P and volume V. Consequently, Carnot cycle that constitutes the principle of a heat engine in gaseous system is also valid on that in magnetic system. A thermomagnetic rotary engine is one model of it that was designed in the form of a ferromagnetic wheel that can rotates because of magnetization change at Curie temperature. The study is aimed to describe the thermodynamic and mechanical analysis of a thermomagnetic rotary engine and calculate the efficiencies. In thermodynamic view, the ideal processes are isothermal demagnetization, adiabatic demagnetization, isothermal magnetization, and adiabatic magnetization. The values of thermodynamic efficiency depend on temperature difference between hot and cold reservoir. In mechanical view, a rotational work is determined through calculation of moment of inertia and average angular speed. The value of mechanical efficiency is calculated from ratio between rotational work and heat received by system. The study also obtains exergetic efficiency that states the performance quality of the engine. (paper)
Thermodynamic and Mechanical Analysis of a Thermomagnetic Rotary Engine
Fajar, D. M.; Khotimah, S. N.; Khairurrijal
2016-08-01
A heat engine in magnetic system had three thermodynamic coordinates: magnetic intensity ℋ, total magnetization ℳ, and temperature T, where the first two of them are respectively analogous to that of gaseous system: pressure P and volume V. Consequently, Carnot cycle that constitutes the principle of a heat engine in gaseous system is also valid on that in magnetic system. A thermomagnetic rotary engine is one model of it that was designed in the form of a ferromagnetic wheel that can rotates because of magnetization change at Curie temperature. The study is aimed to describe the thermodynamic and mechanical analysis of a thermomagnetic rotary engine and calculate the efficiencies. In thermodynamic view, the ideal processes are isothermal demagnetization, adiabatic demagnetization, isothermal magnetization, and adiabatic magnetization. The values of thermodynamic efficiency depend on temperature difference between hot and cold reservoir. In mechanical view, a rotational work is determined through calculation of moment of inertia and average angular speed. The value of mechanical efficiency is calculated from ratio between rotational work and heat received by system. The study also obtains exergetic efficiency that states the performance quality of the engine.
International Nuclear Information System (INIS)
Mokhtari, F.; Bouabdallah, A.; Merah, A.; Oualli, H.
2012-01-01
The effect of axial magnetic field of different intensities on pressure in silicon Czochralski crystal growth is investigated in cylindrical and hemispherical geometries with rotating crystal and crucible and thermocapillary convection. As one important thermodynamic variable, the pressure is found to be more sensitive than temperature to magnetic field with strong dependence upon the vorticity field. The pressure at the triple point is proposed as a convenient parameter to control the homogeneity of the grown crystal. With a gradual increase of the magnetic field intensity the convection effect can be reduced without thermal fluctuations in the silicon melt. An evaluation of the magnetic interaction parameter critical value corresponding to flow, pressure and temperature homogenization leads to the important result that a relatively low axial magnetic field is required for the spherical system comparatively to the cylindrical one. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Energy Technology Data Exchange (ETDEWEB)
Mokhtari, F. [Universite Mouloud Mammeri de Tizi Ouzou (Algeria); LTSE Laboratory, University of Science and Technology. BP 32 Elalia, Babezzouar, Algiers (Algeria); Bouabdallah, A. [LTSE Laboratory, University of Science and Technology. BP 32 Elalia, Babezzouar, Algiers (Algeria); Merah, A. [LTSE Laboratory, University of Science and Technology. BP 32 Elalia, Babezzouar, Algiers (Algeria); M' hamed Bougara University, Boumerdes (Algeria); Oualli, H. [EMP, Bordj ElBahri, Algiers (Algeria)
2012-12-15
The effect of axial magnetic field of different intensities on pressure in silicon Czochralski crystal growth is investigated in cylindrical and hemispherical geometries with rotating crystal and crucible and thermocapillary convection. As one important thermodynamic variable, the pressure is found to be more sensitive than temperature to magnetic field with strong dependence upon the vorticity field. The pressure at the triple point is proposed as a convenient parameter to control the homogeneity of the grown crystal. With a gradual increase of the magnetic field intensity the convection effect can be reduced without thermal fluctuations in the silicon melt. An evaluation of the magnetic interaction parameter critical value corresponding to flow, pressure and temperature homogenization leads to the important result that a relatively low axial magnetic field is required for the spherical system comparatively to the cylindrical one. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Pressure dependence of critical temperature of bulk FeSe from spin fluctuation theory
Hirschfeld, Peter; Kreisel, Andreas; Wang, Yan; Tomic, Milan; Jeschke, Harald; Jacko, Anthony; Valenti, Roser; Maier, Thomas; Scalapino, Douglas
2013-03-01
The critical temperature of the 8K superconductor FeSe is extremely sensitive to pressure, rising to a maximum of 40K at about 10GPa. We test the ability of the current generation of fluctuation exchange pairing theories to account for this effect, by downfolding the density functional theory electronic structure for each pressure to a tight binding model. The Fermi surface found in such a procedure is then used with fixed Hubbard parameters to determine the pairing strength using the random phase approximation for the spin singlet pairing vertex. We find that the evolution of the Fermi surface captured by such an approach is alone not sufficient to explain the observed pressure dependence, and discuss alternative approaches. PJH, YW, AK were supported by DOE DE-FG02-05ER46236, the financial support of MT, HJ, and RV from the DFG Schwerpunktprogramm 1458 is kindly acknowledged.
Fission product thermodynamic data: technical progress report 1 January-30 June 1991
International Nuclear Information System (INIS)
Ball, R.G.J.; Yates, A.D.; Bowsher, B.R.; Dickinson, S.; Freemantle, N.E.; Day, T.; Ogden, J.S.
1991-07-01
Thermodynamic data are being determined for a number of compounds formed from specific fission products and reactor materials. The compounds selected for experimental study and critical assessment were chosen because their thermodynamic data were inadequate or did not exist, as assessed and recommended at a specialists' meeting. These data can be used in the appropriate computer code so that the speciation and transport properties of the fission products can be predicted during a severe reactor accident. Experimental studies have focussed on the vaporization of tellurium dioxide, caesium ruthenate, strontium borate and indium hydroxide. Critical evaluations have begun for a number of tellurides of importance in severe accident assessments, and preliminary analyses have been made of the Fe-Te, Ni-Te and Cr-Te systems. (author)
Pressure and Compressibility of Conformal Field Theories from the AdS/CFT Correspondence
Directory of Open Access Journals (Sweden)
Brian P. Dolan
2016-05-01
Full Text Available The equation of state associated with N = 4 supersymmetric Yang–Mills in four dimensions, for S U ( N in the large N limit, is investigated using the AdS/CFT correspondence. An asymptotically AdS black-hole on the gravity side provides a thermal background for the Yang–Mills theory on the boundary in which the cosmological constant is equivalent to a volume. The thermodynamic variable conjugate to the cosmological constant is a pressure, and the P - V diagram of the quark-gluon plasma is studied. It is known that there is a critical point where the heat capacity diverges, and this is reflected in the isothermal compressibility. Critical exponents are derived and found to be mean field in the large N limit. The same analysis applied to three- and six-dimensional conformal field theories again yields mean field exponents associated with the compressibility at the critical point.
Eichhorn, Ralf; Aurell, Erik
2014-04-01
'Stochastic thermodynamics as a conceptual framework combines the stochastic energetics approach introduced a decade ago by Sekimoto [1] with the idea that entropy can consistently be assigned to a single fluctuating trajectory [2]'. This quote, taken from Udo Seifert's [3] 2008 review, nicely summarizes the basic ideas behind stochastic thermodynamics: for small systems, driven by external forces and in contact with a heat bath at a well-defined temperature, stochastic energetics [4] defines the exchanged work and heat along a single fluctuating trajectory and connects them to changes in the internal (system) energy by an energy balance analogous to the first law of thermodynamics. Additionally, providing a consistent definition of trajectory-wise entropy production gives rise to second-law-like relations and forms the basis for a 'stochastic thermodynamics' along individual fluctuating trajectories. In order to construct meaningful concepts of work, heat and entropy production for single trajectories, their definitions are based on the stochastic equations of motion modeling the physical system of interest. Because of this, they are valid even for systems that are prevented from equilibrating with the thermal environment by external driving forces (or other sources of non-equilibrium). In that way, the central notions of equilibrium thermodynamics, such as heat, work and entropy, are consistently extended to the non-equilibrium realm. In the (non-equilibrium) ensemble, the trajectory-wise quantities acquire distributions. General statements derived within stochastic thermodynamics typically refer to properties of these distributions, and are valid in the non-equilibrium regime even beyond the linear response. The extension of statistical mechanics and of exact thermodynamic statements to the non-equilibrium realm has been discussed from the early days of statistical mechanics more than 100 years ago. This debate culminated in the development of linear response
High-pressure phase transition and phase diagram of gallium arsenide
Besson, J. M.; Itié, J. P.; Polian, A.; Weill, G.; Mansot, J. L.; Gonzalez, J.
1991-09-01
Under hydrostatic pressure, cubic GaAs-I undergoes phase transitions to at least two orthorhombic structures. The initial phase transition to GaAs-II has been investigated by optical-transmittance measurements, Raman scattering, and x-ray absorption. The structure of pressurized samples, which are retrieved at ambient, has been studied by x-ray diffraction and high-resolution diffraction microscopy. Various criteria that define the domain of stability of GaAs-I are examined, such as the occurrence of crystalline defects, the local variation in atomic coordination number, or the actual change in crystal structure. These are shown not to occur at the same pressure at 300 K, the latter being observable only several GPa above the actual thermodynamic instability pressure of GaAs-I. Comparison of the evolution of these parameters on increasing and decreasing pressure locates the thermodynamic transition region GaAs-I-->GaAs-II at 12+/-1.5 GPa and at 300 K that is lower than generally reported. The use of thermodynamic relations around the triple point, and of regularities in the properties of isoelectronic and isostructural III-V compounds, yields a phase diagram for GaAs which is consistent with this value.
Energy Technology Data Exchange (ETDEWEB)
Bouhemadou, A., E-mail: a_bouhemadou@yahoo.fr [Laboratory for Developing New Materials and their Characterization, Department of Physics, Faculty of Science, University of Setif, 19000 Setif (Algeria); Haddadi, K. [Laboratory for Developing New Materials and their Characterization, Department of Physics, Faculty of Science, University of Setif, 19000 Setif (Algeria); Khenata, R. [Laboratoire de Physique Quantique et de Modelisation Mathematique (LPQ3M), Departement de Technologie, Universite de Mascara, 29000 Mascara (Algeria); Rached, D. [Department of Physics, Faculty of Science, University of Sidi-Bel-Abbes, 22000 (Algeria); Bin-Omran, S. [Department of Physics and Astronomy, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451 (Saudi Arabia)
2012-06-15
A density functional-based method is used to investigate the structural, elastic and thermodynamic properties of the cubic spinel semiconductors MgIn{sub 2}S{sub 4} and CdIn{sub 2}S{sub 4} at different pressures and temperatures. Computed ground structural parameters are in good agreement with the available experimental data. Single-crystal elastic parameters are calculated for pressure up to 10 GPa and temperature up to 1200 K. The obtained elastic constants values satisfy the requirement of mechanical stability, indicating that MgIn{sub 2}S{sub 4} and CdIn{sub 2}S{sub 4} compounds could be stable in the investigated pressure range. Isotropic elastic parameters for ideal polycrystalline MgIn{sub 2}S{sub 4} and CdIn{sub 2}S{sub 4} aggregates are computed in the framework of the Voigt-Reuss-Hill approximation. Pressure and thermal effects on some macroscopic properties such as lattice constant, volume expansion coefficient and heat capacities are predicted using the quasi-harmonic Debye model in which the lattice vibrations are taken into account.
Thermodynamic behaviour of tellurium at high temperatures
International Nuclear Information System (INIS)
Garisto, F.
1992-09-01
Thermodynamic calculations are used to determine the chemical speciation of tellurium in the primary heat transport system under postulated reactor accident conditions. The speciation of tellurium is determined for various values of the temperature, oxygen partial pressure, tellurium concentration and Cs/Te ratio. The effects of the Zircaloy cladding and/or cesium on tellurium speciation and volatility are of particular interest in this report. (Author) (37 refs., 14 figs., 4 tabs.)
International Nuclear Information System (INIS)
Alberty, R.A.; Oppenheim, I.
1993-01-01
When temperature, pressure, and the partial pressure of a reactant are fixed, the criterion of chemical equilibrium can be expressed in terms of the transformed Gibbs energy G' that is obtained by using a Legendre transform involving the chemical potential of the reactant that is fixed. For reactions of ideal gases, the most natural variables to use in the fundamental equation are T, P', and P B , where P' is the partial pressure of the reactants other than the one that is fixed and P B is the partial pressure of the reactant that is fixed. The fundamental equation for G' yields the expression for the transformed entropy S', and a transformed enthalpy can be defined by the additional Legendre transform H'=G'+TS'. This leads to an additional form of the fundamental equation. The calculation of transformed thermodynamic properties and equilibrium compositions is discussed for a simple system and for a general multireaction system. The change, in a reaction, of the binding of the reactant that is at a specified pressure can be calculated using one of the six Maxwell equations of the fundamental equation in G'
A thermodynamic counterpart of the Axelrod model of social influence: The one-dimensional case
Gandica, Y.; Medina, E.; Bonalde, I.
2013-12-01
We propose a thermodynamic version of the Axelrod model of social influence. In one-dimensional (1D) lattices, the thermodynamic model becomes a coupled Potts model with a bonding interaction that increases with the site matching traits. We analytically calculate thermodynamic and critical properties for a 1D system and show that an order-disorder phase transition only occurs at T=0 independent of the number of cultural traits q and features F. The 1D thermodynamic Axelrod model belongs to the same universality class of the Ising and Potts models, notwithstanding the increase of the internal dimension of the local degree of freedom and the state-dependent bonding interaction. We suggest a unifying proposal to compare exponents across different discrete 1D models. The comparison with our Hamiltonian description reveals that in the thermodynamic limit the original out-of-equilibrium 1D Axelrod model with noise behaves like an ordinary thermodynamic 1D interacting particle system.
International Nuclear Information System (INIS)
Dubovitskii, V.A.; Pavlov, G.A.; Krasnikov, Yu.G.
1996-01-01
Thermodynamic analysis of media with strong interparticle (Coulomb) interaction is presented. A method for constructing isotherms is proposed for a medium described by a closed multicomponent thermodynamic model. The method is based on choosing an appropriate nondegenerate frame of reference in the extended space of thermodynamic variables and provides efficient thermodynamic calculations in a wide range of parameters, for an investigation of phase transitions of the first kind, and for determining both the number of phases and coexistence curves. A number of approximate thermodynamic models of hydrogen plasma are discussed. The approximation corresponding to the n5/2 law, in which the effects of particle attraction and repulsion are taken into account qualitatively, is studied. This approximation allows studies of thermodynamic properties of a substance for a wide range of parameters. In this approximation, for hydrogen at a constant temperature, various properties of the degree of ionization are revealed. In addition, the parameters of the second critical point are found under conditions corresponding to the Jovian interior
Improved actions for QCD thermodynamics on the lattice
Beinlich, B; Laermann, E
1996-01-01
Finite cut-off effects strongly influence the thermodynamics of lattice regularized QCD at high temperature in the standard Wilson formulation. We analyze the reduction of finite cut-off effects in formulations of the thermodynamics of SU(N) gauge theories with three different O(a^2) and O(a^4) improved actions. We calculate the energy density and pressure on finite lattices in leading order weak coupling perturbation theory (T\\rightarrow \\infty) and perform Monte Carlo simulations with improved SU(3) actions at non-zero g^2. Already on lattices with temporal extent N_\\tau=4 we find a strong reduction of finite cut-off effects in the high temperature limit, which persists also down to temperatures a few times the deconfinement transition temperature.
Energy Technology Data Exchange (ETDEWEB)
Hölzl, Christoph; Horinek, Dominik, E-mail: dominik.horinek@ur.de [Institut für Physikalische und Theoretische Chemie, Universität Regensburg, 93040 Regensburg (Germany); Kibies, Patrick; Frach, Roland; Kast, Stefan M., E-mail: stefan.kast@tu-dortmund.de [Physikalische Chemie III, Technische Universität Dortmund, 44227 Dortmund (Germany); Imoto, Sho, E-mail: sho.imoto@theochem.rub.de; Marx, Dominik [Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum (Germany); Suladze, Saba; Winter, Roland [Physikalische Chemie I, Technische Universität Dortmund, 44227 Dortmund (Germany)
2016-04-14
Accurate force fields are one of the major pillars on which successful molecular dynamics simulations of complex biomolecular processes rest. They have been optimized for ambient conditions, whereas high-pressure simulations become increasingly important in pressure perturbation studies, using pressure as an independent thermodynamic variable. Here, we explore the design of non-polarizable force fields tailored to work well in the realm of kilobar pressures – while avoiding complete reparameterization. Our key is to first compute the pressure-induced electronic and structural response of a solute by combining an integral equation approach to include pressure effects on solvent structure with a quantum-chemical treatment of the solute within the embedded cluster reference interaction site model (EC-RISM) framework. Next, the solute’s response to compression is taken into account by introducing pressure-dependence into selected parameters of a well-established force field. In our proof-of-principle study, the full machinery is applied to N,N,N-trimethylamine-N-oxide (TMAO) in water being a potent osmolyte that counteracts pressure denaturation. EC-RISM theory is shown to describe well the charge redistribution upon compression of TMAO(aq) to 10 kbar, which is then embodied in force field molecular dynamics by pressure-dependent partial charges. The performance of the high pressure force field is assessed by comparing to experimental and ab initio molecular dynamics data. Beyond its broad usefulness for designing non-polarizable force fields for extreme thermodynamic conditions, a good description of the pressure-response of solutions is highly recommended when constructing and validating polarizable force fields.
Hölzl, Christoph; Kibies, Patrick; Imoto, Sho; Frach, Roland; Suladze, Saba; Winter, Roland; Marx, Dominik; Horinek, Dominik; Kast, Stefan M
2016-04-14
Accurate force fields are one of the major pillars on which successful molecular dynamics simulations of complex biomolecular processes rest. They have been optimized for ambient conditions, whereas high-pressure simulations become increasingly important in pressure perturbation studies, using pressure as an independent thermodynamic variable. Here, we explore the design of non-polarizable force fields tailored to work well in the realm of kilobar pressures--while avoiding complete reparameterization. Our key is to first compute the pressure-induced electronic and structural response of a solute by combining an integral equation approach to include pressure effects on solvent structure with a quantum-chemical treatment of the solute within the embedded cluster reference interaction site model (EC-RISM) framework. Next, the solute's response to compression is taken into account by introducing pressure-dependence into selected parameters of a well-established force field. In our proof-of-principle study, the full machinery is applied to N,N,N-trimethylamine-N-oxide (TMAO) in water being a potent osmolyte that counteracts pressure denaturation. EC-RISM theory is shown to describe well the charge redistribution upon compression of TMAO(aq) to 10 kbar, which is then embodied in force field molecular dynamics by pressure-dependent partial charges. The performance of the high pressure force field is assessed by comparing to experimental and ab initio molecular dynamics data. Beyond its broad usefulness for designing non-polarizable force fields for extreme thermodynamic conditions, a good description of the pressure-response of solutions is highly recommended when constructing and validating polarizable force fields.
International Nuclear Information System (INIS)
Hölzl, Christoph; Horinek, Dominik; Kibies, Patrick; Frach, Roland; Kast, Stefan M.; Imoto, Sho; Marx, Dominik; Suladze, Saba; Winter, Roland
2016-01-01
Accurate force fields are one of the major pillars on which successful molecular dynamics simulations of complex biomolecular processes rest. They have been optimized for ambient conditions, whereas high-pressure simulations become increasingly important in pressure perturbation studies, using pressure as an independent thermodynamic variable. Here, we explore the design of non-polarizable force fields tailored to work well in the realm of kilobar pressures – while avoiding complete reparameterization. Our key is to first compute the pressure-induced electronic and structural response of a solute by combining an integral equation approach to include pressure effects on solvent structure with a quantum-chemical treatment of the solute within the embedded cluster reference interaction site model (EC-RISM) framework. Next, the solute’s response to compression is taken into account by introducing pressure-dependence into selected parameters of a well-established force field. In our proof-of-principle study, the full machinery is applied to N,N,N-trimethylamine-N-oxide (TMAO) in water being a potent osmolyte that counteracts pressure denaturation. EC-RISM theory is shown to describe well the charge redistribution upon compression of TMAO(aq) to 10 kbar, which is then embodied in force field molecular dynamics by pressure-dependent partial charges. The performance of the high pressure force field is assessed by comparing to experimental and ab initio molecular dynamics data. Beyond its broad usefulness for designing non-polarizable force fields for extreme thermodynamic conditions, a good description of the pressure-response of solutions is highly recommended when constructing and validating polarizable force fields.
Kojitani, Hiroshi; Yamazaki, Monami; Kojima, Meiko; Inaguma, Yoshiyuki; Mori, Daisuke; Akaogi, Masaki
2018-06-01
Heat capacity (C P) of rutile and α-PbO2 type TiO2 (TiO2-II) were measured by the differential scanning calorimetry and thermal relaxation method. Using the results, standard entropies at 1 atm and 298.15 K of rutile and TiO2-II were determined to be 50.04(4) and 46.54(2) J/mol K, respectively. Furthermore, thermal expansivity (α) determined by high-temperature X-ray diffraction measurement and mode Grüneisen parameters obtained by high-pressure Raman spectroscopy suggested the thermal Grüneisen parameter (γ th) for TiO2-II of 1.7(1). By applying the obtained low-temperature C P and γ th, the measured C P and α data of TiO2-II were extrapolated to higher temperature region using a lattice vibrational model calculation, as well as rutile. Internally consistent thermodynamic data sets of both rutile and TiO2-II assessed in this study were used to thermodynamically calculate the rutile‒TiO2-II phase equilibrium boundary. The most plausible boundary was obtained to be P (GPa) = 0.0074T (K) - 1.7. Our boundary suggests that the crystal growth of TiO2-II observed below 5.5 GPa and 900 K in previous studies advanced in its stability field. The phase boundary calculation also suggested small, exothermic phase transition enthalpy from rutile to TiO2-II at 1 atm and 298.15 K of - 0.5 to - 1.1 kJ/mol. This implies that the thermodynamic stability of rutile at 1 atm above room temperature is due to larger contribution of entropy term.
Energy Technology Data Exchange (ETDEWEB)
Corradini, Michael [Univ. of Wisconsin, Madison, WI (United States); Wu, Qiao [Oregon State Univ., Corvallis, OR (United States)
2015-04-30
This report is a preliminary document presenting an overview of the Critical Heat Flux (CHF) phenomenon, the High Pressure Critical Heat Flux facility (HPCHF), preliminary CHF data acquired, and the future direction of the research. The HPCHF facility has been designed and built to study CHF at high pressure and low mass flux ranges in a rod bundle prototypical of conceptual Small Modular Reactor (SMR) designs. The rod bundle is comprised of four electrically heated rods in a 2x2 square rod bundle with a prototypic chopped-cosine axial power profile and equipped with thermocouples at various axial and circumferential positions embedded in each rod for CHF detection. Experimental test parameters for CHF detection range from pressures of ~80 – 160 bar, mass fluxes of ~400 – 1500 kg/m2s, and inlet water subcooling from ~30 – 70°C. The preliminary data base established will be further extended in the future along with comparisons to existing CHF correlations, models, etc. whose application ranges may be applicable to the conditions of SMRs.
Thermodynamic behaviour of a coated conductor for currents above Ic
International Nuclear Information System (INIS)
Schwarz, M; Schacherer, Chr; Weiss, K-P; Jung, A
2008-01-01
Coated conductors are becoming more and more applicable. The temperature range below the critical value (T c ) or below the critical current (I c ) is well characterized. But for applications such as fault current limiters, which take advantage of the superconducting-to-normal transition, characterization beyond the superconducting regime is mandatory. Therefore, this work studies the thermodynamic behaviour of a coated conductor immersed in boiling liquid nitrogen which is driven by a sinusoidal over-current of up to more than five times I c . The temperature of the coated conductor exceeds 720 K without any significant degradation. To validate this current-induced high-temperature region, the resistance of the composite tape is measured from T c to 600 K. A thermodynamic and electrical model is conceptualized for calculating the temperature, developing as a function of time during over-currents. The calculated temperature fits well with the measured temperature
Brain activity and cognition: a connection from thermodynamics and information theory.
Collell, Guillem; Fauquet, Jordi
2015-01-01
The connection between brain and mind is an important scientific and philosophical question that we are still far from completely understanding. A crucial point to our work is noticing that thermodynamics provides a convenient framework to model brain activity, whereas cognition can be modeled in information-theoretical terms. In fact, several models have been proposed so far from both approaches. A second critical remark is the existence of deep theoretical connections between thermodynamics and information theory. In fact, some well-known authors claim that the laws of thermodynamics are nothing but principles in information theory. Unlike in physics or chemistry, a formalization of the relationship between information and energy is currently lacking in neuroscience. In this paper we propose a framework to connect physical brain and cognitive models by means of the theoretical connections between information theory and thermodynamics. Ultimately, this article aims at providing further insight on the formal relationship between cognition and neural activity.
Brain activity and cognition: a connection from thermodynamics and information theory
Collell, Guillem; Fauquet, Jordi
2015-01-01
The connection between brain and mind is an important scientific and philosophical question that we are still far from completely understanding. A crucial point to our work is noticing that thermodynamics provides a convenient framework to model brain activity, whereas cognition can be modeled in information-theoretical terms. In fact, several models have been proposed so far from both approaches. A second critical remark is the existence of deep theoretical connections between thermodynamics and information theory. In fact, some well-known authors claim that the laws of thermodynamics are nothing but principles in information theory. Unlike in physics or chemistry, a formalization of the relationship between information and energy is currently lacking in neuroscience. In this paper we propose a framework to connect physical brain and cognitive models by means of the theoretical connections between information theory and thermodynamics. Ultimately, this article aims at providing further insight on the formal relationship between cognition and neural activity. PMID:26136709
Energy Technology Data Exchange (ETDEWEB)
Sengupta, Tapan K., E-mail: tksen@iitk.ac.in; Bhole, Ashish; Shruti, K. S. [HPCL, Department of Aerospace Engineering, IIT Kanpur, Kanpur, UP (India); Sengupta, Aditi [Department of Engineering, University of Cambridge, Cambridge (United Kingdom); Sharma, Nidhi [Graduate Student, HPCL, Department of Aerospace Engineering, IIT Kanpur, Kanpur, UP (India); Sengupta, Soumyo [Department of Mechanical and Aerospace Engineering, Ohio State University, Columbus, Ohio 43210 (United States)
2016-09-15
Direct numerical simulations of Rayleigh-Taylor instability (RTI) between two air masses with a temperature difference of 70 K is presented using compressible Navier-Stokes formulation in a non-equilibrium thermodynamic framework. The two-dimensional flow is studied in an isolated box with non-periodic walls in both vertical and horizontal directions. The non-conducting interface separating the two air masses is impulsively removed at t = 0 (depicting a heaviside function). No external perturbation has been used at the interface to instigate the instability at the onset. Computations have been carried out for rectangular and square cross sections. The formulation is free of Boussinesq approximation commonly used in many Navier-Stokes formulations for RTI. Effect of Stokes’ hypothesis is quantified, by using models from acoustic attenuation measurement for the second coefficient of viscosity from two experiments. Effects of Stokes’ hypothesis on growth of mixing layer and evolution of total entropy for the Rayleigh-Taylor system are reported. The initial rate of growth is observed to be independent of Stokes’ hypothesis and the geometry of the box. Following this stage, growth rate is dependent on the geometry of the box and is sensitive to the model used. As a consequence of compressible formulation, we capture pressure wave-packets with associated reflection and rarefaction from the non-periodic walls. The pattern and frequency of reflections of pressure waves noted specifically at the initial stages are reflected in entropy variation of the system.
Thermodynamic assessment of integrated biogas-based micro-power generation system
International Nuclear Information System (INIS)
Hosseini, Seyed Ehsan; Barzegaravval, Hasan; Wahid, Mazlan Abdul; Ganjehkaviri, Abdolsaeid; Sies, Mohsin Mohd
2016-01-01
Highlights: • A thermodynamic modelling of an integrated biogas-based micro-power generation system is reported. • The impact of design parameters on the thermodynamic performance of the system is evaluated. • High turbine inlet temperatures lead the system to the higher energy and exergy efficiency and higher power generation. • Enhancement of GT isentropic efficiency incurs negative effects on the performance of air preheater and heat exchanger. • The rate of power generation increases by the enhancement of steam turbine pressure in ORC. - Abstract: In this paper, a thermodynamic modelling of an integrated biogas (60%CH_4 + 40%CO_2) micro-power generation system for electricity generation is reported. This system involves a gas turbine cycle and organic Rankine cycle (ORC) where the wasted heat of gas turbine cycle is recovered by closed ORC. The net output power of the micro-power generation system is fixed at 1.4 MW includes 1 MW power generated by GT and 0.4 MW by ORC. Energy and exergy assessments and related parametric studies are carried out, and parameters that influence on energy and exergy efficiency are evaluated. The performance of the system with respect to variation of design parameters such as combustion air inlet temperature, turbine inlet temperature, compressor pressure ratio, gas turbine isentropic efficiency and compressor isentropic efficiency (from the top cycle) and steam turbine inlet pressure, and condenser pressure (from bottoming cycle) is evaluated. The results reveal that by the increase of gas turbine isentropic efficiency, the outlet temperature of gas turbine decreases which incurs negative impacts on the performance of air preheater and heat exchanger, however the energy and exergy efficiency increases in the whole system. By the increase of air compressor pressure ratio, the energy and exergy of the combined cycle decreases. The exergy efficiency of ORC alters by the variation of gas turbine parameters which can be
Thermodynamic properties of citric acid and the system citric acid-water
Kruif, C.G. de; Miltenburg, J.C. van; Sprenkels, A.J.J.; Stevens, G.; Graaf, W. de; Wit, H.G.M. de
1982-01-01
The binary system citric acid-water has been investigated with static vapour pressure measurements, adiabatic calorimetry, solution calorimetry, solubility measurements and powder X-ray measurements. The data are correlated by thermodynamics and a large part of the phase diagram is given. Molar heat
Thermodynamic stability of warped AdS{sub 3} black holes
Energy Technology Data Exchange (ETDEWEB)
Birmingham, Danny, E-mail: dbirmingham@pacific.ed [Department of Physics, University of the Pacific, Stockton, CA 95211 (United States); Mokhtari, Susan, E-mail: susan@science.csustan.ed [Department of Physics, California State University Stanislaus, Turlock, CA 95382 (United States)
2011-02-21
We study the thermodynamic stability of warped black holes in three-dimensional topologically massive gravity. The spacelike stretched black hole is parametrized by its mass and angular momentum. We determine the local and global stability properties in the canonical and grand canonical ensembles. The presence of a Hawking-Page type transition is established, and the critical temperature is determined. The thermodynamic metric of Ruppeiner is computed, and the curvature is shown to diverge in the extremal limit. The consequences of these results for the classical stability properties of warped black holes are discussed within the context of the correlated stability conjecture.