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Sample records for properties thermodynamic properties

  1. Thermodynamic properties of cerium mononitride

    NASA Astrophysics Data System (ADS)

    Aristova, N. M.; Belov, G. V.

    2014-09-01

    Data on the thermodynamic properties of cerium mononitride CeN in the solid state are analyzed. Relations approximating the temperature dependence of the thermodynamic functions of CeN(cr.) in the temperature range of 298.15-2900 K are obtained. Using the relations of thermodynamics known for this temperature range, the thermodynamic functions of cerium mononitride (entropy, Gibbs energy, and enthalpy variation) are calculated. The resulting data is entered into the database of the IVTANTHERMO software package and is used to analyze the thermal stability of CeN(cr.), and to estimate its boiling point at atmospheric pressure.

  2. Thermodynamic Properties of Supported Catalysts

    SciTech Connect

    Gorte, Raymond J.

    2014-03-26

    The goals of this work were to develop Coulometric Titration as a method for characterizing the thermodynamic redox properties of oxides and to apply this technique to the characterization of ceria- and vanadia-based catalysts. The redox properties of ceria and vanadia are a major part of what makes these materials catalytically active but their properties are also dependent on their structure and the presence of other oxides. Quantifying these properties through the measurement of oxidation energetics was the goal of this work.

  3. The Thermodynamic Properties of Cubanite

    NASA Technical Reports Server (NTRS)

    Berger, E. L.; Lauretta, D. S.; Keller, L. P.

    2012-01-01

    CuFe2S3 exists in two polymorphs, a low-temperature orthorhombic form (cubanite) and a high-temperature cubic form (isocubanite). Cubanite has been identified in the CI-chondrite and Stardust collections. However, the thermodynamic properties of cubanite have neither been measured nor estimated. Our derivation of a thermodynamic model for cubanite allows constraints to be placed on the formation conditions. This data, along with the temperature constraint afforded by the crystal structure, can be used to assess the environments in which cubanite formation is (or is not) thermodynamically favored.

  4. Thermodynamic properties of minerals

    USGS Publications Warehouse

    Robie, Richard A.

    1962-01-01

    In the ten years since the publication of the national Bureau of Standards comprehensive tables of thermochemical properties, by Rossini and other (1952), a very large body of modern calorimetric and equilibrium data has become available. Because of the complex interrelations among many thermochemical data and the necessity for internal consistency among these values, a complete revision of this standard reference is required. This is also true of the summaries of thermochemical data for the sulfides (Richardson and Jeffes 1952) and for the oxides (Coughlin 1954). The following tables present critically selected values for the heat and free energy of formation, the logarithm of the equilibrium constant of formation Log Kf, the entropy and the molar volume, at 298.15°K (25.0°C) and one atmosphere for minerals.

  5. Thermodynamic properties of uranium dioxide

    SciTech Connect

    Fink, J.K.; Chasanov, M.G.; Leibowitz, L.

    1981-04-01

    In order to provide reliable and consistent data on the thermophysical properties of reactor materials for reactor safety studies, this revision is prepared for the thermodynamic properties of the uranium dioxide portion of the fuel property section of the report Properties for LMFBR Safety Analysis. Since the original report was issued in 1976, there has been international agreement on a vapor pressure equation for the total pressure over UO/sub 2/, new methods have been suggested for the calculation of enthalpy and heat capacity, and a phase change at 2670 K has been proposed. In this report, an electronic term is used in place of the Frenkel defect term in the enthalpy and heat capacity equation and the phase transition is accepted.

  6. Thermodynamic properties of sea air

    NASA Astrophysics Data System (ADS)

    Feistel, R.; Kretzschmar, H.-J.; Span, R.; Hagen, E.; Wright, D. G.; Herrmann, S.

    2009-10-01

    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.

  7. Thermodynamic properties of sea air

    NASA Astrophysics Data System (ADS)

    Feistel, R.; Wright, D. G.; Kretzschmar, H.-J.; Hagen, E.; Herrmann, S.; Span, R.

    2010-02-01

    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.

  8. Thermodynamic Properties of Dimethyl Carbonatea)

    NASA Astrophysics Data System (ADS)

    Zhou, Yong; Wu, Jiangtao; Lemmon, Eric W.

    2011-12-01

    A thermodynamic property formulation for dimethyl carbonate has been developed with the use of available experimental thermodynamic property data. The equation of state was developed with multiproperty fitting methods involving pressure-density-temperature (p?T), heat capacity, vapor pressure, and saturated-liquid density data. The equation of state conforms to the Maxwell criterion for two-phase liquid-vapor equilibrium states, and is valid for temperatures from the triple-point temperature (277.06 ± 0.63) K to 600 K, for pressures up to 60 MPa, and for densities up to 12.12 mol dm-3. The extrapolation behavior of the equation of state at low and high temperatures and pressures is reasonable. The uncertainties (k = 2, indicating a 95% confidence level) of the equation of state in density are 0.05% for saturated-liquid states below 350 K, rising to 0.1% in the single phase between 278 K and 400 K at pressures up to 60 MPa. Due to the lack of reliable data outside this region, the estimated uncertainties increase to 0.5% to 1% in the vapor and critical regions. The uncertainties in vapor pressure are 0.6% from 310 K to 400 K, and increase to 1% at higher temperatures and to 2% at lower temperatures due to a lack of experimental data. The uncertainty in isobaric heat capacity and speed of sound in the liquid phase at saturation or atmospheric pressure is 0.5% from 280 K to 335 K. The uncertainties are higher for all properties in the critical region. Detailed comparisons between experimental and calculated data, and an analysis of the equation, have been performed.

  9. CORRELATIONS Modeling Physical and Thermodynamic Properties via Inverse

    E-print Network

    Brauner, Neima

    CORRELATIONS Modeling Physical and Thermodynamic Properties via Inverse Normalizing Transformations in modeling the temperature dependence of various physical and thermodynamic properties. 1. Introduction to represent the physical and thermodynamic properties as a function of state variables such as temperature

  10. Tables of thermodynamic properties of sodium

    SciTech Connect

    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.

  11. Thermodynamic properties of wadsleyite with anharmonic effect

    NASA Astrophysics Data System (ADS)

    Wu, Zhongqing

    2015-02-01

    The thermodynamic properties of crystals can be routinely calculated by density functional theory calculations combining with quasi-harmonic approximation. Based on the method developed recently by Wu and Wentzcovitch (Phys Rev B 79:104304, 2009) and Wu (Phys Rev B 81:172301, 2010), we are able to further ab initio include anharmonic effect on thermodynamic properties of crystals by one additional canonical ensemble with numbers of particle, volume and temperature fixed (NVT) molecular dynamic simulations. Our study indicates that phonon-phonon interaction causes the renormalized phonon frequencies of wadsleyite decrease with temperature. This is consistent with the Raman experimental observation. The anharmonic free energy of wadsleyite is negative and its heat capacity at constant pressure can exceed the Dulong-Petit limit at high temperature. The anharmonicity still significantly affects thermodynamic properties of wadsleyite at pressure and temperature conditions correspond to the transition zone.

  12. Thermodynamic properties of organic iodine compounds

    NASA Astrophysics Data System (ADS)

    Richard, Laurent; Gaona, Xavier

    2011-11-01

    A critical evaluation has been made of the thermodynamic properties reported in the literature for 43 organic iodine compounds in the solid, liquid, or ideal gas state. These compounds include aliphatic, cyclic and aromatic iodides, iodophenols, iodocarboxylic acids, and acetyl and benzoyl iodides. The evaluation has been made on the basis of carbon number systematics and group additivity relations, which also allowed to provide estimates of the thermodynamic properties of those compounds for which no experimental data were available. Standard molal thermodynamic properties at 25 °C and 1 bar and heat capacity coefficients are reported for 13 crystalline, 29 liquid, and 39 ideal gas organic iodine compounds, which can be used to calculate the corresponding properties as a function of temperature and pressure. Values derived for the standard molal Gibbs energy of formation at 25 °C and 1 bar of these crystalline, liquid, and ideal gas organic iodine compounds have subsequently been combined with either solubility measurements or gas/water partition coefficients to obtain values for the standard partial molal Gibbs energies of formation at 25 °C and 1 bar of 32 aqueous organic iodine compounds. The thermodynamic properties of organic iodine compounds calculated in the present study can be used together with those for aqueous inorganic iodine species to predict the organic/inorganic speciation of iodine in marine sediments and petroleum systems, or in the near- and far-field of nuclear waste repositories.

  13. Thermodynamic and transport properties of gaseous tetrafluoromethane in chemical equilibrium

    NASA Technical Reports Server (NTRS)

    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.

  14. Thermodynamic properties of liquid metals and alloys

    NASA Astrophysics Data System (ADS)

    Kessel'Man, P. M.; Bykov, A. Yu.; Inshakov, S. A.

    1990-11-01

    A modified cellular model of liquids is used to develop a method for calculating thermodynamic properties of liquid metals and their alloys, which are widely used in compact modern heat exchange equipment operating at high thermal flux densities. The approach presented herein permits calculation of the properties of metals from various groups by a single consistent technique. Good agreement was found with experimental data for a significant number of liquid metals and their alloys.

  15. Thermodynamic properties of dimethylene urethane

    NASA Astrophysics Data System (ADS)

    Emel'yanenko, V. N.; Turovtsev, V. V.; Orlov, Yu. D.

    2015-07-01

    Enthalpies of the combustion and formation of crystalline dimethylene urethane (oxazolidin-2-one) are determined via combustion calorimetry. The enthalpy of sublimation is determined via the transpiration method, and the enthalpy of fusion is found by means of differential scanning calorimetry. The temperature dependence of the saturated vapor pressure is measured in the range of 323-353 K. Thermodynamic functions in the ideal gas state are calculated using the rigid rotator-anharmonic oscillator model in the range of T = 298.15-1500 K.

  16. Thermodynamical Properties of Hall Systems

    E-print Network

    Ahmed Jellal; Youssef Khedif

    2007-04-23

    We study quantum Hall effect within the framework of a newly proposed approach, which captures the principal results of some proposals. This can be established by considering a system of particles living on the non-commutative plane in the presence of an electromagnetic field and quantum statistical mechanically investigate its basic features. Solving the eigenvalue equation, we analytically derive the energy levels and the corresponding wavefunctions. These will be used, at low temperature and weak electric field, to determine the thermodynamical potential \\Omega^{nc} and related physical quantities. Varying \\Omega^{nc} with respect to the non-commutativity parameter \\theta, we define a new function that can be interpreted as a \\Omega^{nc} density. Evaluating the particle number, we show that the Hall conductivity of the system is \\theta-dependent. This allows us to make contact with quantum Hall effect by offering different interpretations. We study the high temperature regime and discuss the magnetism of the system. We finally show that at \\theta=2l_B^2, the system is sharing some common features with the Laughlin theory.

  17. Thermodynamics and statistical mechanics. [thermodynamic properties of gases

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The basic thermodynamic properties of gases are reviewed and the relations between them are derived from the first and second laws. The elements of statistical mechanics are then formulated and the partition function is derived. The classical form of the partition function is used to obtain the Maxwell-Boltzmann distribution of kinetic energies in the gas phase and the equipartition of energy theorem is given in its most general form. The thermodynamic properties are all derived as functions of the partition function. Quantum statistics are reviewed briefly and the differences between the Boltzmann distribution function for classical particles and the Fermi-Dirac and Bose-Einstein distributions for quantum particles are discussed.

  18. Specification properties and thermodynamical properties of semigroup actions

    E-print Network

    Fagner B. Rodrigues; Paulo Varandas

    2015-03-27

    In the present paper we study the thermodynamical properties of finitely generated continuous subgroup actions. We address a notion of topological entropy and pressure functions that does not depend on the growth rate of the semigroup and introduce strong and orbital specification properties, under which, the semigroup actions have positive topological entropy and all points are entropy points. Moreover, we study the convergence and Lipschitz regularity of the pressure function and obtain relations between topological entropy and exponential growth rate of periodic points in the context of semigroups of expanding maps. The specification properties for semigroup actions and the corresponding one for its generators and the action of push-forward maps is also discussed.

  19. The thermodynamic properties of benzothiazole and benzoxazole

    NASA Astrophysics Data System (ADS)

    Steele, W. V.; Chirico, R. D.; Knipmeyer, S. E.; Nguyen, A.

    1991-08-01

    This research program, funded by the Department of Energy, Office of Fossil Energy, Advanced Extraction and Process Technology, provides accurate experimental thermochemical and thermophysical properties for key organic diheteroatom-containing compounds present in heavy petroleum feedstocks, and applies the experimental information to thermodynamic analyses of key hydrodesulfurization, hydrodenitrogenation, and hydrodeoxygenation reaction networks. Thermodynamic analyses, based on accurate information, provide insights for the design of cost-effective methods of heteroatom removal. The results reported here, and in a companion report to be completed, will point the way to the development of new methods of heteroatom removal from heavy petroleum. Measurements leading to the calculation of the ideal-gas thermodynamic properties are reported for benzothiazole and benzoxazole. Experimental methods included combustion calorimetry, adiabatic heat-capacity calorimetry, comparative ebulliometry, inclinded-piston gauge manometry, and differential-scanning calorimetry (d.s.c). Critical property estimates are made for both compounds. Entropies, enthalpies, and Gibbs energies of formation were derived for the ideal gas for both compounds for selected temperatures between 280 K and near 650 K. The Gibbs energies of formation will be used in a subsequent report in thermodynamic calculations to study the reaction pathways for the removal of the heteratoms by hydrogenolysis. The results obtained in this research are compared with values present in the literature. The failure of a previous adiabatic heat capacity study to see the phase transition in benzothiazole is noted. Literature vibrational frequency assignments were used to calculate ideal gas entropies in the temperature range reported here for both compounds. Resulting large deviations show the need for a revision of those assignments.

  20. The thermodynamic properties of benzothiazole and benzoxazole

    SciTech Connect

    Steele, W.V.; Chirico, R.D.; Knipmeyer, S.E.; Nguyen, A.

    1991-08-01

    This research program, funded by the Department of Energy, Office of Fossil Energy, Advanced Extraction and Process Technology, provides accurate experimental thermochemical and thermophysical properties for key'' organic diheteroatom-containing compounds present in heavy petroleum feedstocks, and applies the experimental information to thermodynamic analyses of key hydrodesulfurization, hydrodenitrogenation, and hydrodeoxygenation reaction networks. Thermodynamic analyses, based on accurate information, provide insights for the design of cost-effective methods of heteroatom removal. The results reported here, and in a companion report to be completed, will point the way to the development of new methods of heteroatom removal from heavy petroleum. Measurements leading to the calculation of the ideal-gas thermodynamic properties are reported for benzothiazole and benzoxazole. Experimental methods included combustion calorimetry, adiabatic heat-capacity calorimetry, comparative ebulliometry, inclinded-piston gauge manometry, and differential-scanning calorimetry (d.s.c). Critical property estimates are made for both compounds. Entropies, enthalpies, and Gibbs energies of formation were derived for the ideal gas for both compounds for selected temperatures between 280 K and near 650 K. The Gibbs energies of formation will be used in a subsequent report in thermodynamic calculations to study the reaction pathways for the removal of the heteratoms by hydrogenolysis. The results obtained in this research are compared with values present in the literature. The failure of a previous adiabatic heat capacity study to see the phase transition in benzothiazole is noted. Literature vibrational frequency assignments were used to calculate ideal gas entropies in the temperature range reported here for both compounds. Resulting large deviations show the need for a revision of those assignments. 68 refs., 6 figs., 15 tabs.

  1. Thermodynamic Properties of Actinides and Actinide Compounds

    NASA Astrophysics Data System (ADS)

    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.

  2. Thermodynamic properties of benzene under shock conditions.

    PubMed

    Maillet, Jean-Bernard; Pineau, Nicolas

    2008-06-14

    We present in this paper a thermodynamic analysis of benzene properties under shock conditions as given by molecular dynamics (MD) simulations. Reactive MD simulations of benzene predict a decomposition threshold corresponding to the flection point on the experimental Hugoniot curve. A polymerlike carbonated structure is observed for pressures above this threshold, but the calculated Hugoniot curve is in disagreement with the experimental one at high pressure. On the contrary, a system consisting of a diamond cluster in hydrogen gas leads to a correct prediction of the pressure on the Hugoniot curves. The central question is then linked to the kinetics of the transition between the polymerlike structure and the diamond cluster. PMID:18554024

  3. A Dynamic Library for Physical and Thermodynamic Properties Correlations

    E-print Network

    Brauner, Neima

    A Dynamic Library for Physical and Thermodynamic Properties Correlations Mordechai Shacham Brauner School of Engineering, Tel-Aviv University, Tel-Aviv 69978, Israel A dynamic physical properties of physical and thermodynamic properties are being used extensively in process calcula- tions and computations

  4. Thermodynamic properties of particles with intermediate statistics

    SciTech Connect

    Joyce, G.S.; Sarkar, S.; Spal Byczuk, K.

    1996-01-01

    Analytic expressions for the distribution function of an ideal gas of particles (exclusons) which have statistics intermediate between Fermi-Dirac and Bose-Einstein are obtained for all values of the Haldane statistics parameter {alpha}{element_of}[0,1]. The analytic structure of the distribution function is investigated and found to have no singularities in the physical region when the parameter {alpha} lies in the range 0{lt}{alpha}{le}1. High- and low-temperature series are also derived for the internal energy {ital E} and heat capacity {ital C}{sub {ital V}} of the {ital D}-dimensional excluson gas. The low-temperature series for the thermodynamic properties illustrate the pseudofermion nature of exclusons. {copyright} {ital 1996 The American Physical Society.}

  5. Prediction of thermodynamic properties of coal derivatives

    SciTech Connect

    Donohue, M.D.

    1992-11-01

    The purpose of this research program is to understand and model the effect of the different intermolecular forces on the thermodynamic properties of systems containing pure compounds and mixtures. The compounds under consideration vary considerably in size, shape and energy. Therefore in order to develop a theory capable of describing accurately the thermodynamic properties and phase behavior of such systems over a wide range of temperature and pressure, one has to take into account explicitly the differences in shape and size among the various compounds as well as the different type of intermolecular interactions. We have developed equations of state for pure-component chain molecules. We have shown that the excellent performance of complicated theories such as the Generalized Flory Dimer (GFD) theory can be mimicked by simpler equations, if certain assumptions for the shape parameters are made. We developed engineering correlations based on the GFD theory, using local composition theory to take into account the attractive contribution. We compared various methods for the calculation of the repulsive and attractive contributions against computer simulation data for hard and square-well chains, and experimental data from the literature. We also have studied microstructure and local order in fluids that contain asymmetric molecules. In addition, simple cubic equations of state have been applied to calculate physical and chemical-reaction equilibria in non-ideal systems. In order to obtain a better understanding of the intermolecular forces and to test some of our recent models, we have performed considerable experimental work. We used FT-IR to examine the self-association of aliphatic alcohols due to hydrogen bonding. In addition, FT-IR spectroscopy was used to investigate Lewis acid-base interactions between probe and entrainer-cosolvent molecules.

  6. Thermodynamic approach to nano-properties of cell membrane

    NASA Astrophysics Data System (ADS)

    Lucia, Umberto

    2014-08-01

    Biomechanical analyses of DNA have pointed out the connections among forces, thermodynamics and kinetics. The entropy generation approach has been suggested as a thermodynamic approach to evaluate the accessible states for cancer systems, in relation to their specific thermodynamic quantities, including mechanical properties. In this paper, a theoretical approach for the thermodynamic evaluation of the nano-behaviour of the cell wall is suggested. The aim is to provide theoretical bases to the analysis of cells and their properties by applying the thermodynamic approach to irreversibility.

  7. Universal relation for size dependent thermodynamic properties of metallic nanoparticles.

    PubMed

    Xiong, Shiyun; Qi, Weihong; Cheng, Yajuan; Huang, Baiyun; Wang, Mingpu; Li, Yejun

    2011-06-14

    The previous model on surface free energy has been extended to calculate size dependent thermodynamic properties (i.e., melting temperature, melting enthalpy, melting entropy, evaporation temperature, Curie temperature, Debye temperature and specific heat capacity) of nanoparticles. According to the quantitative calculation of size effects on the calculated thermodynamic properties, it is found that most thermodynamic properties of nanoparticles vary linearly with 1/D as a first approximation. In other words, the size dependent thermodynamic properties P(n) have the form of P(n) = P(b)(1 -K/D), in which P(b) is the corresponding bulk value and K is the material constant. This may be regarded as a scaling law for most of the size dependent thermodynamic properties for different materials. The present predictions are consistent literature values. PMID:21523307

  8. Calculation of the standard molal thermodynamic properties of crystalline peptides

    NASA Astrophysics Data System (ADS)

    LaRowe, Douglas E.; Dick, Jeffrey M.

    2012-03-01

    To augment the relatively sparse set of thermodynamic data available for high molecular weight biopolymers, group additivity algorithms have been developed to estimate the heat capacity power function coefficients and standard molal thermodynamic properties of crystalline peptides in the multitude of biogeochemical environments in which they are found. Group contributions representing the 20 common amino acids plus 5-hydroxylysine and 4-hydroxyproline for each coefficient and property were generated using the thermodynamic properties of crystalline amino acids, polypeptides and other organic compounds. These group contributions were in turn used to compute the thermodynamic properties of naturally occurring proteins that are found in a crystalline state in cells. The coefficients and properties of the model compounds, group contributions and proteins are tabulated. In a demonstration of the uncertainty of the thermodynamic properties of the groups generated in this study, experimentally determined heat capacities and entropies of crystalline homopolypeptides and proteins taken from the literature have been compared to estimates of these quantities. Additionally, standard molal volumes for 24 amino acids have been recalculated in light of inconsistencies in an earlier analysis, and the standard molal thermodynamic properties of aqueous and crystalline methionine at 25 °C and 0.1 MPa have been reassessed. Calculations of this kind can be carried out to thermodynamically describe the biogeochemical interactions throughout the broad range of environmental settings in which they are known to occur.

  9. Dimensionless thermodynamics: a new paradigm for liquid state properties.

    PubMed

    Sanchez, Isaac C

    2014-08-01

    Equations of state in the van der Waals genre suggest that saturated liquids should adhere to the following corresponding states principle (CSP): saturated liquids at the same reduced density (?R = ?/?c) have comparable dimensionless thermodynamic properties. This CSP is shown to be applicable to a variety of thermodynamic properties that include entropy of vaporization, cohesive energy density, thermal expansion coefficient, isothermal compressibility, thermal pressure coefficient, compressibility factor, temperature coefficient of the vapor pressure, heat capacity difference, and surface tension. For two classes of liquids, all properties rendered dimensionless by the proper choice of scaling variables superpose to form "master curves" that illustrate the CSP. Using scaled particle theory, an improved van der Waals model is developed whose results are compared with existing experimental thermodynamic data in dimensionless form. Properly expressing thermodynamic properties in dimensionless form acts to consolidate and harmonize liquid state properties. PMID:25014632

  10. Composition and Thermodynamic Properties of Air in Chemical Equilibrium

    NASA Technical Reports Server (NTRS)

    Moeckel, W E; Weston, Kenneth C

    1958-01-01

    Charts have been prepared relating the thermodynamic properties of air in chemical equilibrium for temperatures to 15,000 degrees k and for pressures 10(-5) to 10 (plus 4) atmospheres. Also included are charts showing the composition of air, the isentropic exponent, and the speed of sound. These charts are based on thermodynamic data calculated by the National Bureau of Standards. (author)

  11. Thermodynamic property determination in low gravity

    NASA Technical Reports Server (NTRS)

    Margrave, J. L.

    1977-01-01

    Techniques for determining heat capacities and other properties of molten metals were investigated and critically evaluated. Precisely determining heat capacities calorimetrically in space poses several problems. The weight of a drop calorimeter block along with the necessity of obtaining a large number of data points tend to make traditional approaches appear infeasible. However, for many substances exhibiting sufficiently high thermal conductivities and with known emissivities, it appears possible to investigate their properties by observing the rate of cooling of a levitated sphere which is initially at a uniform temperature above the melting point. A special advantage of the levitation method is that considerable supercooling is expected, making the study of the heat capacities of molten metals both above and below their melting points possible.

  12. Thermodynamical properties of graphene in noncommutative phase–space

    SciTech Connect

    Santos, Victor; Maluf, R.V.; Almeida, C.A.S.

    2014-10-15

    We investigated the thermodynamic properties of graphene in a noncommutative phase–space in the presence of a constant magnetic field. In particular, we determined the behaviour of the main thermodynamical functions: the Helmholtz free energy, the mean energy, the entropy and the specific heat. The high temperature limit is worked out and the thermodynamic quantities, such as mean energy and specific heat, exhibit the same features as the commutative case. Possible connections with the results already established in the literature are discussed briefly.

  13. Reference Fluid Thermodynamic and Transport Properties Database (REFPROP)

    National Institute of Standards and Technology Data Gateway

    SRD 23 NIST Reference Fluid Thermodynamic and Transport Properties Database (REFPROP) (PC database for purchase)   NIST 23 contains revised data in a Windows version of the database, including 105 pure fluids and allowing mixtures of up to 20 components. The fluids include the environmentally acceptable HFCs, traditional HFCs and CFCs and 'natural' refrigerants like ammonia

  14. Diameter-dependent thermodynamic and elastic properties of metallic nanoparticles

    NASA Astrophysics Data System (ADS)

    Chandra, Jeewan; Kholiya, Kuldeep

    2015-04-01

    A simple theoretical model has been proposed to study the diameter-dependent properties of metallic nanoparticles, i.e. Ag, Au, Al, Ni, Pb, Cu and Fe. The diameter-dependent thermodynamic properties includes melting temperature, Debye temperature, evaporation temperature, melting enthapy and melting entropy. The model is also extended to study the diameter-dependent elastic properties including bulk modulus, Young's modulus and thermal expansion coefficient. On comparison with available experimental findings and other theoretical approaches, the results obtained with the present formulation depict a close agreement and demonstrate the validity of the method proposed in the present paper.

  15. Thermodynamic properties of fluids from Fluctuation Solution Theory

    SciTech Connect

    O'Connell, J.P.

    1990-01-01

    Fluctuation Theory develops exact relations between integrals of molecular correlation functions and concentration derivatives of pressure and chemical potential. These quantities can be usefully correlated, particularly for mechanical and thermal properties of pure and mixed dense fluids and for activities of strongly nonideal liquid solutions. The expressions yield unique formulae for the desirable thermodynamic properties of activity and density. The molecular theory origins of the flucuation properties, their behavior for systems of technical interest and some of their successful correlations will be described. Suggestions for fruitful directions will be suggested.

  16. Thermodynamic properties of fluids from Fluctuation Solution Theory

    SciTech Connect

    O`Connell, J.P.

    1990-12-31

    Fluctuation Theory develops exact relations between integrals of molecular correlation functions and concentration derivatives of pressure and chemical potential. These quantities can be usefully correlated, particularly for mechanical and thermal properties of pure and mixed dense fluids and for activities of strongly nonideal liquid solutions. The expressions yield unique formulae for the desirable thermodynamic properties of activity and density. The molecular theory origins of the flucuation properties, their behavior for systems of technical interest and some of their successful correlations will be described. Suggestions for fruitful directions will be suggested.

  17. NASA Glenn Coefficients for Calculating Thermodynamic Properties of Individual Species

    NASA Technical Reports Server (NTRS)

    McBride, Bonnie J.; Zehe, Michael J.; Gordon, Sanford

    2002-01-01

    This report documents the library of thermodynamic data used with the NASA Glenn computer program CEA (Chemical Equilibrium with Applications). This library, containing data for over 2000 solid, liquid, and gaseous chemical species for temperatures ranging from 200 to 20,000 K, is available for use with other computer codes as well. The data are expressed as least-squares coefficients to a seven-term functional form for C((sup o)(sub p)) (T) / R with integration constants for H (sup o) (T) / RT and S(sup o) (T) / R. The NASA Glenn computer program PAC (Properties and Coefficients) was used to calculate thermodynamic functions and to generate the least-squares coefficients. PAC input was taken from a variety of sources. A complete listing of the database is given along with a summary of thermodynamic properties at 0 and 298.15 K.

  18. Computational Models of Thermodynamic Properties of Uranium Nitride

    NASA Astrophysics Data System (ADS)

    Mei, Zhi-Gang; Stan, Marius

    2014-06-01

    The structural, elastic, electronic, phonon and thermodynamic properties of uranium nitride (UN) have been systematically studied by density functional theory (DFT) calculations. The calculated electronic band structure shows that UN is a metallic phase. The ground state structural and elastic properties predicted by DFT agree well with experiments. The thermodynamic properties of UN are studied by quasiharmonic approximation by including both lattice vibrational and thermal electronic contributions to free energies. The calculated enthalpy, entropy, Gibbs energy and heat capacity show an excellent agreement with experimental results. The thermal electronic contribution due to 5f electrons of U is found to be critical to describe the free energy of UN due to its metallic character.

  19. Thermodynamic properties of gaseous ruthenium species.

    PubMed

    Miradji, Faoulat; Souvi, Sidi; Cantrel, Laurent; Louis, Florent; Vallet, Valérie

    2015-05-21

    The review of thermodynamic data of ruthenium oxides reveals large uncertainties in some of the standard enthalpies of formation, motivating the use of high-level relativistic correlated quantum chemical methods to reduce the level of discrepancies. The reaction energies leading to the formation of ruthenium oxides RuO, RuO2, RuO3, and RuO4 have been calculated for a series of reactions. The combination of different quantum chemical methods has been investigated [DFT, CASSCF, MRCI, CASPT2, CCSD(T)] in order to predict the geometrical parameters, the energetics including electronic correlation and spin-orbit coupling. The most suitable method for ruthenium compounds is the use of TPSSh-5%HF for geometry optimization, followed by CCSD(T) with complete basis set (CBS) extrapolations for the calculation of the total electronic energies. SO-CASSCF seems to be accurate enough to estimate spin-orbit coupling contributions to the ground-state electronic energies. This methodology yields very accurate standard enthalpies of formations of all species, which are either in excellent agreement with the most reliable experimental data or provide an improved estimate for the others. These new data will be implemented in the thermodynamical databases that are used by the ASTEC code (accident source term evaluation code) to build models of ruthenium chemistry behavior in severe nuclear accident conditions. The paper also discusses the nature of the chemical bonds both from molecular orbital and topological view points. PMID:25905631

  20. Thermodynamic properties of bulk and confined water

    SciTech Connect

    Mallamace, Francesco; Corsaro, Carmelo; Mallamace, Domenico; Vasi, Sebastiano; Vasi, Cirino; Stanley, H. Eugene

    2014-11-14

    The thermodynamic response functions of water display anomalous behaviors. We study these anomalous behaviors in bulk and confined water. We use nuclear magnetic resonance (NMR) to examine the configurational specific heat and the transport parameters in both the thermal stable and the metastable supercooled phases. The data we obtain suggest that there is a behavior common to both phases: that the dynamics of water exhibit two singular temperatures belonging to the supercooled and the stable phase, respectively. One is the dynamic fragile-to-strong crossover temperature (T{sub L} ? 225 K). The second, T{sup *} ? 315 ± 5 K, is a special locus of the isothermal compressibility K{sub T}(T, P) and the thermal expansion coefficient ?{sub P}(T, P) in the P–T plane. In the case of water confined inside a protein, we observe that these two temperatures mark, respectively, the onset of protein flexibility from its low temperature glass state (T{sub L}) and the onset of the unfolding process (T{sup *})

  1. Thermodynamic properties and atomic structure of Ca-based liquid alloys

    E-print Network

    Poizeau, Sophie (Sophie Marie Claire)

    2013-01-01

    To identify the most promising positive electrodes for Ca-based liquid metal batteries, the thermodynamic properties of diverse Ca-based liquid alloys were investigated. The thermodynamic properties of Ca-Sb alloys were ...

  2. Intermolecular interactions and the thermodynamic properties of supercritical fluids.

    PubMed

    Yigzawe, Tesfaye M; Sadus, Richard J

    2013-05-21

    The role of different contributions to intermolecular interactions on the thermodynamic properties of supercritical fluids is investigated. Molecular dynamics simulation results are reported for the energy, pressure, thermal pressure coefficient, thermal expansion coefficient, isothermal and adiabatic compressibilities, isobaric and isochoric heat capacities, Joule-Thomson coefficient, and speed of sound of fluids interacting via both the Lennard-Jones and Weeks-Chandler-Andersen potentials. These properties were obtained for a wide range of temperatures, pressures, and densities. For each thermodynamic property, an excess value is determined to distinguish between attraction and repulsion. It is found that the contributions of intermolecular interactions have varying effects depending on the thermodynamic property. The maxima exhibited by the isochoric and isobaric heat capacities, isothermal compressibilities, and thermal expansion coefficient are attributed to interactions in the Lennard-Jones well. Repulsion is required to obtain physically realistic speeds of sound and both repulsion and attraction are necessary to observe a Joule-Thomson inversion curve. Significantly, both maxima and minima are observed for the isobaric and isochoric heat capacities of the supercritical Lennard-Jones fluid. It is postulated that the loci of these maxima and minima converge to a common point via the same power law relationship as the phase coexistence curve with an exponent of ? = 0.32. This provides an explanation for the terminal isobaric heat capacity maximum in supercritical fluids. PMID:23697423

  3. Thermodynamic and melting properties of RDX at elevated pressures

    NASA Technical Reports Server (NTRS)

    Carlson, D. W.; Nauflett, G. W.; Brasch, J. W., Sr.; Austin, T. D.

    1980-01-01

    The laboratory set up for determination of melting and thermodynamic properties of RDX using a diamond anvil cell apparatus capable of pressures exceeding 10 kbar and 250 C is described. The slope of the melting temperature versus applied pressure curve for RDX, as determined in the diamond cell, was found to equal 4.09 + or - 0.6 C (kbar). The density of liquid RDX at its melting point was calculated from this slope to be approximately 1.63 gm/cu cm. Practical and theoretical considerations in using the diamond anvil cell to generate thermodynamic data on RDX are discussed.

  4. Property.

    ERIC Educational Resources Information Center

    Piele, Philip K.

    Several court cases involving acquisition, use, and disposal of property by institutions of higher education are briefly summarized in this chapter. Cases discussed touch on such topics as municipal annexation of university property; repurchase of properties temporarily allocated to faculty members; implications of zoning laws and zoning board…

  5. Thermodynamic properties and diffusion of water + methane binary mixtures

    SciTech Connect

    Shvab, I.; Sadus, Richard J.

    2014-03-14

    Thermodynamic and diffusion properties of water + methane mixtures in a single liquid phase are studied using NVT molecular dynamics. An extensive comparison is reported for the thermal pressure coefficient, compressibilities, expansion coefficients, heat capacities, Joule-Thomson coefficient, zero frequency speed of sound, and diffusion coefficient at methane concentrations up to 15% in the temperature range of 298–650 K. The simulations reveal a complex concentration dependence of the thermodynamic properties of water + methane mixtures. The compressibilities, heat capacities, and diffusion coefficients decrease with increasing methane concentration, whereas values of the thermal expansion coefficients and speed of sound increase. Increasing methane concentration considerably retards the self-diffusion of both water and methane in the mixture. These effects are caused by changes in hydrogen bond network, solvation shell structure, and dynamics of water molecules induced by the solvation of methane at constant volume conditions.

  6. Thermodynamic properties of massive dilaton black holes, 2

    E-print Network

    Tamaki, T

    2002-01-01

    We numerically reanalyze static and spherically symmetric black hole solutions in an Einstein-Maxwell-dilaton system with a dilaton potential $m_{d}^{2}\\phi^{2}$. We investigate thermodynamic properties for various dilaton coupling constants and find that thermodynamic properties change at a critical dilaton mass $m_{d,crit}$. For $m_{d}\\geq m_{d,crit}$, the black hole becomes an extreme solution for a nonzero horizon radius $r_{h,ex}$ as the Reissner-Nordstr\\"om black hole. However, if $m_{d}$ is nearly equal to $m_{d,crit}$, there appears a solution of smaller horizon radius than $r_{h,ex}$. For $m_{d}

  7. Thermodynamic and magnetic properties of the hexagonal type Ising nanowire

    NASA Astrophysics Data System (ADS)

    Kocakaplan, Yusuf; Kantar, Ersin

    2014-06-01

    The thermodynamic and magnetic properties of the mixed-spin (1/2-1) hexagonal Ising nanowire (HIN) system with core-shell structure have been presented by means of the effective-field theory (EFT) with correlations. The effects of the physical parameters of the system on thermodynamic and magnetic properties (magnetisations, susceptibilities, internal energies, free energies and hysteresis curves) are investigated for the both ferromagnetic and antiferromagnetic case, in detail. One can find that when the temperature increases the hysteresis loop areas decrease and the hysteresis loops disappear above the critical temperature. Moreover, different hysteresis loop behaviours have been observed such as single, double and triple hysteresis loops in the system. In order to confirm the accuracy of the phase transition points, we also investigate the free energy of the system.

  8. Accessing Thermodynamic Fluid Properties in LabVIEW

    E-print Network

    Grohmann, S

    2001-01-01

    LabVIEW users that are experimenting with fluid circuits and want to have an online evaluation of measuring data need to import thermodynamic properties of the working fluid. This document describes how CRYODATA's software package GASPAK can be accessed from LabVIEW via ActiveX Automation. An interface server has been developed to enable inter-application communication. The installation of the server is explained and its function calls are demonstrated in a set of example VIs.

  9. Thermodynamic and magnetocaloric properties of geometrically frustrated Ising nanoclusters

    NASA Astrophysics Data System (ADS)

    Žukovi?, M.

    2015-01-01

    Thermodynamic and magnetocaloric properties of geometrically frustrated Ising spin clusters of selected shapes and sizes are studied by exact enumeration. In the ground state the magnetization and the entropy show step-wise variations with an applied magnetic field. The number of steps, their widths and heights depend on the cluster shape and size. While the character of the magnetization plateau heights is always increasing, the entropy is not necessarily decreasing function of the field, as one would expect. For selected clusters showing some interesting ground-state properties, the calculations are extended to finite temperatures by exact enumeration of densities of states in the energy-magnetization space. In zero field the focus is laid on a peculiar behavior of some thermodynamic quantities, such as the entropy, the specific heat and the magnetic susceptibility. In finite fields various thermodynamic functions are studied in the temperature-field parameter plane and particular attention is paid to the cases showing an enhanced magnetocaloric effect. The exact results on the finite clusters are compared with the thermodynamic limit behavior obtained from Monte Carlo simulations.

  10. Coefficients for calculating thermodynamic and transport properties of individual species

    NASA Technical Reports Server (NTRS)

    Mcbride, Bonnie J.; Gordon, Sanford; Reno, Martin A.

    1993-01-01

    Libraries of thermodynamic data and transport properties are given for individual species in the form of least-squares coefficients. Values of C(sup 0)(sub p)(T), H(sup 0)(T), and S(sup 0)(T) are available for 1130 solid, liquid, and gaseous species. Viscosity and thermal conductivity data are given for 155 gases. The original C(sup 0)(sub p)(T) values were fit to a fourth-order polynomial with integration constants for H(sup 0)(T) and S(sup 0)(T). For each species the integration constant for H(sup 0)(T) includes the heat of formation. Transport properties have a different functional form. The temperature range for most of the data is 300 to 5000 K, although some of the newer thermodynamic data have a range of 200 to 6000 K. Because the species are mainly possible products of reaction, the data are useful for chemical equilibrium and kinetics computer codes. Much of the data has been distributed for several years with the NASA Lewis equilibrium program CET89. The thermodynamic properties of the reference elements were updated along with about 175 species that involve the elements carbon, hydrogen, oxygen, and nitrogen. These sets of data will be distributed with the NASA Lewis personal computer program for calculating chemical equilibria, CETPC.

  11. Structural and thermodynamics properties of organo-modified montmorillonite clay

    NASA Astrophysics Data System (ADS)

    Anoukou, K.; Zaoui, A.; Zaïri, F.; Naït-Abdelaziz, M.; Gloaguen, J. M.

    2015-01-01

    Polymer clay nanocomposites (PCNs) have been seen as the most novel materials in engineering applications since they exhibit significant improvement in mechanical and physical properties. Indeed, with few amount of organoclay, PCNs exhibit enhanced mechanical, optical, thermal and liquid or gas barrier properties compared to pure polymers and to their counterpart microcomposites. Thus, organoclays are extensively used as precursors in the preparation of PCNs. They are the best candidate in reinforcing PCNs because of the lightweight and the high availability of clay minerals in the nature. However, structure and physical phenomena arising at molecular level in organoclays, and subsequently in PCNs, are not completely or difficultly accessible with existing experimental techniques. In this work, molecular dynamics (MD) simulation was conducted using the combination of two force fields (CLAYFF and CHARMM) to evaluate the thermodynamics and structural properties of organoclay such as heat capacities, isothermal bulk modulus, density, basal spacing and chains arrangement in the interlayer spacing. Our results regarding the basal spacing and density are in fairly good agreement with available experimental data. This allows us to validate the use of the two force fields to represent interactions in organoclays. The effect of the cation exchange capacity (CEC) on the basal spacing and the thermodynamics properties is assessed. We found, through our MD simulation, that the calculated isothermal bulk modulus is in good agreement with the density value of organoclays with two different CEC.

  12. Optical and thermodynamic property measurements of liquid metals and alloys

    NASA Technical Reports Server (NTRS)

    Weber, J. K. R.; Krishnan, Shankar; Schiffman, Robert A.; Nordine, Paul C.

    1991-01-01

    Optical properties and spectral emissivities of liquid silicon, titanium, niobium, and zirconium were investigated by HeNe laser polarimetry at 632.8 nm. The metals were of a high purity and, except for zirconium, clean. The more demanding environmental requirements for eliminating oxide or nitride phases from zirconium were not met. Containerless conditions were achieved by electromagnetic levitation and heating. CO2 laser beam heating was also used to extend the temperature range for stable levitation and to heat solid silicon to form the metallic liquid phase. Corrections to previously reported calorimetric measurements of the heat capacity of liquid niobium were derived from the measured temperature dependence of its spectral emissivity. Property measurements were obtained for supercooled liquid silicon and supercooling of liquid zirconium was accomplished. The purification of liquid metals and the extension of this work on liquids to the measurement of thermodynamic properties and phase equilibria are discussed.

  13. Property.

    ERIC Educational Resources Information Center

    Piele, Philip K.

    Chapter 7 of a book on school law, this chapter deals with 1979 cases involving disputes over property. Cases involving taxpayer attempts to prevent the construction of school buildings dominate this year's property chapter, as they did last year's. Yet, paradoxically, there is also a significant increase in cases in which taxpayers tried to…

  14. Property.

    ERIC Educational Resources Information Center

    Piele, Philip K.; Johnson, Margaret M.

    This chapter deals with 1981 cases involving disputes over property. Cases involving the detachment and attachment of land continue to dominate the property chapter with 11 cases reported, the same number summarized in last year's chapter. One case involving school board referenda raised the interesting question of whether or not a state could…

  15. Thermodynamic properties of asymptotically Reissner–Nordström black holes

    SciTech Connect

    Hendi, S.H.

    2014-07-15

    Motivated by possible relation between Born–Infeld type nonlinear electrodynamics and an effective low-energy action of open string theory, asymptotically Reissner–Nordström black holes whose electric field is described by a nonlinear electrodynamics (NLED) are studied. We take into account a four dimensional topological static black hole ansatz and solve the field equations, exactly, in terms of the NLED as a matter field. The main goal of this paper is investigation of thermodynamic properties of the obtained black holes. Moreover, we calculate the heat capacity and find that the nonlinearity affects the minimum size of stable black holes. We also use Legendre-invariant metric proposed by Quevedo to obtain scalar curvature divergences. We find that the singularities of the Ricci scalar in Geometrothermodynamics (GTD) method take place at the Davies points. -- Highlights: •We examine the thermodynamical properties of black holes in Einstein gravity with nonlinear electrodynamics. •We investigate thermodynamic stability and discuss about the size of stable black holes. •We obtain analytical solutions of higher dimensional theory.

  16. Thermodynamic properties of magnetic strings on a square lattice

    NASA Astrophysics Data System (ADS)

    Mol, Lucas; Oliveira, Denis Da Mata; Bachmann, Michael

    2015-03-01

    In the last years, spin ice systems have increasingly attracted attention by the scientific community, mainly due to the appearance of collective excitations that behave as magnetic monopole like particles. In these systems, geometrical frustration induces the appearance of degenerated ground states characterized by a local energy minimization rule, the ice rule. Violations of this rule were shown to behave like magnetic monopoles connected by a string of dipoles that carries the magnetic flux from one monopole to the other. In order to obtain a deeper knowledge about the behavior of these excitations we study the thermodynamics of a kind of magnetic polymer formed by a chain of magnetic dipoles in a square lattice. This system is expected to capture the main properties of monopole-string excitations in the artificial square spin ice. It has been found recently that in this geometry the monopoles are confined, but the effective string tension is reduced by entropic effects. To obtain the thermodynamic properties of the strings we have exactly enumerated all possible string configurations of a given length and used standard statistical mechanics analysis to calculate thermodynamic quantities. We show that the low-temperature behavior is governed by strings that satisfy ice rules. Financial support from FAPEMIG and CNPq (Brazilian agencies) are gratefully acknowledged.

  17. Thermodynamic and structural properties of Bi-based liquid alloys

    NASA Astrophysics Data System (ADS)

    Yadav, S. K.; Jha, L. N.; Adhikari, D.

    2015-10-01

    Thermodynamic and microscopic structural properties of two Bi-based liquid alloys, such as In-Bi at 900 K and Tl-Bi at 750 K have been studied employing the regular associated solution model. We have estimated the mole fractions of the complexes and the free monomers assuming the existence of complexes In2 Bi in In-Bi melt and TlBi in Tl-Bi melt. The thermodynamic properties have been studied by computing the Gibbs free energy of mixing, enthalpy of mixing, entropy of mixing and activities of the monomers. The compositional contributions of the heat associated with the formation of complexes and the heat of mixing of the monomers to the net enthalpy change has also been studied. The structural properties of the liquid alloys have been studied by computing concentration fluctuation in the long-wavelength limit, chemical short-range order parameter and the ratio of mutual to intrinsic diffusion coefficients. For both of the alloy systems, the theoretical as well as the experimental values of SCC (0) are found to be lower than the corresponding ideal values over the whole composition range, indicating the hetero-coordinating nature of Bi-In and Bi-Tl alloy melts. All the interaction energy parameters are found to be negative and temperature dependent, and both the alloy systems are found to be weakly interacting.

  18. Thermodynamic properties of liquid gallium from picosecond acoustic velocity measurements

    NASA Astrophysics Data System (ADS)

    Ayrinhac, S.; Gauthier, M.; Le Marchand, G.; Morand, M.; Bergame, F.; Decremps, F.

    2015-07-01

    Due to discrepancies in the literature data the thermodynamic properties of liquid gallium are still in debate. Accurate measurements of adiabatic sound velocities as a function of pressure and temperature have been obtained by the combination of laser picosecond acoustics and surface imaging on sample loaded in diamond anvil cell. From these results the thermodynamic parameters of gallium have been extracted by a numerical procedure up to 10 GPa and 570 K. It is demonstrated that a Murnaghan equation of state accounts well for the whole data set since the isothermal bulk modulus BT has been shown to vary linearly with pressure in the whole temperature range. No evidence for a previously reported liquid-liquid transition has been found in the whole pressure and temperature range explored.

  19. Simplified curve fits for the thermodynamic properties of equilibrium air

    NASA Astrophysics Data System (ADS)

    Srinivasan, S.; Tannehill, J. C.; Weilmuenster, K. J.

    1987-08-01

    New, improved curve fits for the thermodynamic properties of equilibrium air have been developed. The curve fits are for pressure, speed of sound, temperature, entropy, enthalpy, density, and internal energy. These curve fits can be readily incorporated into new or existing computational fluid dynamics codes if real gas effects are desired. The curve fits are constructed from Grabau-type transition functions to model the thermodynamic surfaces in a piecewise manner. The accuracies and continuity of these curve fits are substantially improved over those of previous curve fits. These improvements are due to the incorporation of a small number of additional terms in the approximating polynomials and careful choices of the transition functions. The ranges of validity of the new curve fits are temperatures up to 25 000 K and densities from 10 to the -7 to 10 to the 3d power amagats.

  20. Thermodynamic properties of liquid gallium from picosecond acoustic velocity measurements.

    PubMed

    Ayrinhac, S; Gauthier, M; Le Marchand, G; Morand, M; Bergame, F; Decremps, F

    2015-07-15

    Due to discrepancies in the literature data the thermodynamic properties of liquid gallium are still in debate. Accurate measurements of adiabatic sound velocities as a function of pressure and temperature have been obtained by the combination of laser picosecond acoustics and surface imaging on sample loaded in diamond anvil cell. From these results the thermodynamic parameters of gallium have been extracted by a numerical procedure up to 10 GPa and 570 K. It is demonstrated that a Murnaghan equation of state accounts well for the whole data set since the isothermal bulk modulus BT has been shown to vary linearly with pressure in the whole temperature range. No evidence for a previously reported liquid-liquid transition has been found in the whole pressure and temperature range explored. PMID:26061830

  1. Simplified curve fits for the thermodynamic properties of equilibrium air

    NASA Technical Reports Server (NTRS)

    Srinivasan, S.; Tannehill, J. C.; Weilmuenster, K. J.

    1987-01-01

    New, improved curve fits for the thermodynamic properties of equilibrium air have been developed. The curve fits are for pressure, speed of sound, temperature, entropy, enthalpy, density, and internal energy. These curve fits can be readily incorporated into new or existing computational fluid dynamics codes if real gas effects are desired. The curve fits are constructed from Grabau-type transition functions to model the thermodynamic surfaces in a piecewise manner. The accuracies and continuity of these curve fits are substantially improved over those of previous curve fits. These improvements are due to the incorporation of a small number of additional terms in the approximating polynomials and careful choices of the transition functions. The ranges of validity of the new curve fits are temperatures up to 25 000 K and densities from 10 to the -7 to 10 to the 3d power amagats.

  2. Thermodynamic properties of gases dissolved in electrolyte solutions.

    NASA Technical Reports Server (NTRS)

    Tiepel, E. W.; Gubbins, K. E.

    1973-01-01

    A method based on perturbation theory for mixtures is applied to the prediction of thermodynamic properties of gases dissolved in electrolyte solutions. The theory is compared with experimental data for the dependence of the solute activity coefficient on concentration, temperature, and pressure; calculations are included for partial molal enthalpy and volume of the dissolved gas. The theory is also compared with previous theories for salt effects and found to be superior. The calculations are best for salting-out systems. The qualitative feature of salting-in is predicted by the theory, but quantitative predictions are not satisfactory for such systems; this is attributed to approximations made in evaluating the perturbation terms.

  3. Interaction potentials and thermodynamic properties of two component semiclassical plasma

    SciTech Connect

    Ramazanov, T. S.; Moldabekov, Zh. A.; Ismagambetova, T. N.; Gabdullin, M. T.

    2014-01-15

    In this paper, the effective interaction potential in two component semiclassical plasma, taking into account the long-range screening and the quantum-mechanical diffraction effects at short distances, is obtained on the basis of dielectric response function method. The structural properties of the semiclassical plasma are considered. The thermodynamic characteristics (the internal energy and the equation of state) are calculated using two methods: the method of effective potentials and the method of micropotentials with screening effect taken into account by the Ornstein-Zernike equation in the HNC approximation.

  4. Thermodynamic properties of small aggregates of rare-gas atoms

    NASA Technical Reports Server (NTRS)

    Etters, R. D.; Kaelberer, J.

    1975-01-01

    The present work reports on the equilibrium thermodynamic properties of small clusters of xenon, krypton, and argon atoms, determined from a biased random-walk Monte Carlo procedure. Cluster sizes ranged from 3 to 13 atoms. Each cluster was found to have an abrupt liquid-gas phase transition at a temperature much less than for the bulk material. An abrupt solid-liquid transition is observed for thirteen- and eleven-particle clusters. For cluster sizes smaller than 11, a gradual transition from solid to liquid occurred over a fairly broad range of temperatures. Distribution of number of bond lengths as a function of bond length was calculated for several systems at various temperatures. The effects of box boundary conditions are discussed. Results show the importance of a correct description of boundary conditions. A surprising result is the slow rate at which system properties approach bulk behavior as cluster size is increased.

  5. FLUID- THERMODYNAMIC AND TRANSPORT PROPERTIES OF FLUIDS (IBM PC VERSION)

    NASA Technical Reports Server (NTRS)

    Fessler, T. E.

    1994-01-01

    The accurate computation of the thermodynamic and transport properties of fluids is a necessity for many engineering calculations. The FLUID program was developed to calculate the thermodynamic and transport properties of pure fluids in both the liquid and gas phases. Fluid properties are calculated using a simple gas model, empirical corrections, and an efficient numerical interpolation scheme. FLUID produces results that are in very good agreement with measured values, while being much faster than older more complex programs developed for the same purpose. A Van der Waals equation of state model is used to obtain approximate state values. These values are corrected for real-gas effects by model correction factors obtained from tables based on experimental data. These tables also accurately compensate for the special circumstances which arise whenever phase conditions occur. Viscosity and thermal conductivity values are computed directly from tables. Interpolation within tables is based on Lagrange's three point formula. A set of tables must be generated for each fluid implemented. FLUID currently contains tables for nine fluids including dry air and steam. The user can add tables for any fluid for which adequate thermal property data is available. The FLUID routine is structured so that it may easily be incorporated into engineering programs. The IBM 360 version of FLUID was developed in 1977. It is written in FORTRAN IV and has been implemented on an IBM 360 with a central memory requirement of approximately 222K of 8 bit bytes. The IBM PC version of FLUID is written in Microsoft FORTRAN 77 and has been implemented on an IBM PC with a memory requirement of 128K of 8 bit bytes. The IBM PC version of FLUID was developed in 1986.

  6. Computer program for calculation of thermodynamic and transport properties of complex chemical systems

    NASA Technical Reports Server (NTRS)

    Svehla, R. A.; Mcbride, B. J.

    1973-01-01

    Program performs calculations such as chemical equilibrium for assigned thermodynamic states, theoretical rocket performance for both equilibrium and frozen compositions during expansion, incident and reflected shock properties, and Chapman-Jouget detonation properties. Features include simplicity of input and storage of all thermodynamic and transport property data on master tape.

  7. Structural, electronic, vibrational and thermodynamical properties of surfaces and nanoparticles

    NASA Astrophysics Data System (ADS)

    Yildirim, Handan

    The main focus of the thesis is to have better understanding of the atomic and electronic structures, vibrational dynamics and thermodynamics of metallic surfaces and bi-metallic nanoparticles (NPs) via a multi-scale simulational approach. The research presented here involves the study of the physical and chemical properties of metallic surfaces and NPs that are useful to determine their functionality in building novel materials. The study follows the "bottom-up" approach for which the knowledge gathered at the scale of atoms and NPs serves as a base to build, at the macroscopic scale, materials with desired physical and chemical properties. We use a variety of theoretical and computational tools with different degrees of accuracy to study problems in different time and length scales. Interactions between the atoms are derived using both Density Functional Theory (DFT) and Embedded Atom Method (EAM), depending on the scale of the problem at hand. For some cases, both methods are used for the purpose of comparison. For revealing the local contributions to the vibrational dynamics and thermodynamics for the systems possessing site-specific environments, a local approach in real-space is used, namely Real Space Green's Function method (RSGF). For simulating diffusion of atoms/clusters and growth on metal surfaces, Molecular Statics (MS) and Molecular Dynamics (MD) methods are employed.

  8. Chemical and Thermodynamic Properties at High Temperatures: A Symposium

    NASA Technical Reports Server (NTRS)

    Walker, Raymond F.

    1961-01-01

    This book contains the program and all available abstracts of the 90' invited and contributed papers to be presented at the TUPAC Symposium on Chemical and Thermodynamic Properties at High Temperatures. The Symposium will be held in conjunction with the XVIIIth IUPAC Congress, Montreal, August 6 - 12, 1961. It has been organized, by the Subcommissions on Condensed States and on Gaseous States of the Commission on High Temperatures and Refractories and by the Subcommission on Experimental Thermodynamics of the Commission on Chemical Thermodynamics, acting in conjunction with the Organizing Committee of the IUPAC Congress. All inquiries concerning participation In the Symposium should be directed to: Secretary, XVIIIth International Congress of Pure and Applied Chemistry, National Research Council, Ottawa, 'Canada. Owing to the limited time and facilities available for the preparation and printing of the book, it has not been possible to refer the proofs of the abstracts to the authors for checking. Furthermore, it has not been possible to subject the manuscripts to a very thorough editorial examination. Some obvious errors in the manuscripts have been corrected; other errors undoubtedly have been introduced. Figures have been redrawn only when such a step was essential for reproduction purposes. Sincere apologies are offered to authors and readers for any errors which remain; however, in the circumstances neither the IUPAC Commissions who organized the Symposium, nor the U. S. Government Agencies who assisted in the preparation of this book can accept responsibility for the errors.

  9. New Results on the Thermodynamic Properties of the Climate System

    NASA Astrophysics Data System (ADS)

    Lucarini, Valerio; Fraedrich, Klaus; Ragone, Francesco

    2011-10-01

    In this paper we exploit two equivalent formulations of the average rate of material entropy production in a planetary system to propose an approximate splitting between contributions due to vertical and eminently horizontal processes. Our approach is based only upon 2D radiative fields at the surface and at the top of atmosphere of a general planetary body. Using 2D fields at the top of atmosphere alone, we derive lower bounds to the rate of material entropy production and to the intensity of the Lorenz energy cycle. By introducing a measure of the efficiency of the planetary system with respect to horizontal thermodynamical processes, we provide insight on a previous intuition on the possibility of defining a baroclinic heat engine extracting work from the meridional heat flux. The approximate formula of the material entropy production is verified and used for studying the global thermodynamic properties of climate models (CMs) included in the PCMDI/CMIP3 dataset in pre-industrial climate conditions. It is found that about 90% of the material entropy production is due to vertical processes such as convection, whereas the large scale meridional heat transport contributes only about 10%. The total material entropy production is typically 55 mWK-1m-2, with discrepancies of the order of 5% and CMs' baroclinic efficiencies are clustered around 0.055. When looking at the variability and co-variability of the considered thermodynamical quantities, the agreement among CMs is worse, suggesting that the description of feedbacks is more uncertain.

  10. Property.

    ERIC Educational Resources Information Center

    Piele, Philip K.

    Numerous cases in this year's chapter dealt with the same topics of previous years--contracts and bids for building construction, and detachment and annexation of a portion of a school district. The courts continued to attribute board discretionary authority to school boards in school property matters. Intergovernmental disputes over ownership or…

  11. Thermodynamic properties of the Group 1A elements

    SciTech Connect

    Alcock, C.B.; Itkin, V.P.; Chase, M.W.

    1994-05-01

    This review describes thermodynamic properties of condensed phases of the alkali metals, excluding francium for which the amount of information is too limited. The properties considered are: heat capacities from 0 to 1600 K, temperatures and enthalpies of fusion and martensitic transformation in Li and Na; discussion of the Debye temperature and electronic heat capacity coefficient at absolute zero temperature is also included. The paper is the second part of a series. Similar to previous assessment of the IIA group [93ALC/CHA], this paper considers original studies, especially with respect to factors which influence the accuracy and reliability of results. Recommendations derived from such analyses are compared with most advanced previous reviews made at the Institute for High Temperatures (Moscow) [70SHP/YAK], [82GUR] and the National Institute of Standards and Technology (Washington) [85JAN]. The properties of individual elements of the group are compared and suggestions are made for experimental studies which should improve poorly measured quantities. The review is supplemented by an IBM PC database which contains references, assessed data, brief description of studies and has facilities for fitting and plotting of data and for adding new information.

  12. Thermodynamic and transport combustion properties of hydrocarbons with air. Part 1: Properties in SI units

    NASA Technical Reports Server (NTRS)

    Gordon, S.

    1982-01-01

    Thermodynamic and transport combustion properties were calculated for a wide range of conditions for the reaction of hydrocarbons with air. Three hydrogen-carbon atom ratios (H/C = 1.7, 2.0, 2.1) were selected to represent the range of aircraft fuels. For each of these H/C ratios, combustion properties were calculated for the following conditions: Equivalence ratio: 0, 0.25, 0.5, 0.75, 1.0, 1.25 Water - dry air mass ratio: 0, 0.03 Pressure, kPa: 1.01325, 10.1325, 101.325, 1013.25, 5066.25 (or in atm: 0.01, 0.1, 1, 10, 50) Temperature, K: every 10 degrees from 200 to 900 K; every 50 degrees from 900 to 3000 K Temperature, R: every 20 degrees from 360 to 1600 R; very 100 degrees from 1600 to 5400 R. The properties presented are composition, density, molecular weight, enthalphy, entropy, specific heat at constant pressure, volume derivatives, isentropic exponent, velocity of sound, viscosity, thermal conductivity, and Prandtl number. Property tables are based on composites that were calculated by assuming both: (1) chemical equilibrium (for both homogeneous and heterogeneous phases) and (2) constant compositions for all temperatures. Properties in SI units are presented in this report for the Kelvin temperature schedules.

  13. ms2: A molecular simulation tool for thermodynamic properties

    NASA Astrophysics Data System (ADS)

    Deublein, Stephan; Eckl, Bernhard; Stoll, Jürgen; Lishchuk, Sergey V.; Guevara-Carrion, Gabriela; Glass, Colin W.; Merker, Thorsten; Bernreuther, Martin; Hasse, Hans; Vrabec, Jadran

    2011-11-01

    This work presents the molecular simulation program ms2 that is designed for the calculation of thermodynamic properties of bulk fluids in equilibrium consisting of small electro-neutral molecules. ms2 features the two main molecular simulation techniques, molecular dynamics (MD) and Monte-Carlo. It supports the calculation of vapor-liquid equilibria of pure fluids and multi-component mixtures described by rigid molecular models on the basis of the grand equilibrium method. Furthermore, it is capable of sampling various classical ensembles and yields numerous thermodynamic properties. To evaluate the chemical potential, Widom's test molecule method and gradual insertion are implemented. Transport properties are determined by equilibrium MD simulations following the Green-Kubo formalism. ms2 is designed to meet the requirements of academia and industry, particularly achieving short response times and straightforward handling. It is written in Fortran90 and optimized for a fast execution on a broad range of computer architectures, spanning from single processor PCs over PC-clusters and vector computers to high-end parallel machines. The standard Message Passing Interface (MPI) is used for parallelization and ms2 is therefore easily portable to different computing platforms. Feature tools facilitate the interaction with the code and the interpretation of input and output files. The accuracy and reliability of ms2 has been shown for a large variety of fluids in preceding work. Program summaryProgram title:ms2 Catalogue identifier: AEJF_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEJF_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Special Licence supplied by the authors No. of lines in distributed program, including test data, etc.: 82 794 No. of bytes in distributed program, including test data, etc.: 793 705 Distribution format: tar.gz Programming language: Fortran90 Computer: The simulation tool ms2 is usable on a wide variety of platforms, from single processor machines over PC-clusters and vector computers to vector-parallel architectures. (Tested with Fortran compilers: gfortran, Intel, PathScale, Portland Group and Sun Studio.) Operating system: Unix/Linux, Windows Has the code been vectorized or parallelized?: Yes. Message Passing Interface (MPI) protocol Scalability. Excellent scalability up to 16 processors for molecular dynamics and >512 processors for Monte-Carlo simulations. RAM:ms2 runs on single processors with 512 MB RAM. The memory demand rises with increasing number of processors used per node and increasing number of molecules. Classification: 7.7, 7.9, 12 External routines: Message Passing Interface (MPI) Nature of problem: Calculation of application oriented thermodynamic properties for rigid electro-neutral molecules: vapor-liquid equilibria, thermal and caloric data as well as transport properties of pure fluids and multi-component mixtures. Solution method: Molecular dynamics, Monte-Carlo, various classical ensembles, grand equilibrium method, Green-Kubo formalism. Restrictions: No. The system size is user-defined. Typical problems addressed by ms2 can be solved by simulating systems containing typically 2000 molecules or less. Unusual features: Feature tools are available for creating input files, analyzing simulation results and visualizing molecular trajectories. Additional comments: Sample makefiles for multiple operation platforms are provided. Documentation is provided with the installation package and is available at http://www.ms-2.de. Running time: The running time of ms2 depends on the problem set, the system size and the number of processes used in the simulation. Running four processes on a "Nehalem" processor, simulations calculating VLE data take between two and twelve hours, calculating transport properties between six and 24 hours.

  14. An Interpolation Method for Obtaining Thermodynamic Properties Near Saturated Liquid and Saturated Vapor Lines

    NASA Technical Reports Server (NTRS)

    Nguyen, Huy H.; Martin, Michael A.

    2004-01-01

    The two most common approaches used to formulate thermodynamic properties of pure substances are fundamental (or characteristic) equations of state (Helmholtz and Gibbs functions) and a piecemeal approach that is described in Adebiyi and Russell (1992). This paper neither presents a different method to formulate thermodynamic properties of pure substances nor validates the aforementioned approaches. Rather its purpose is to present a method to generate property tables from existing property packages and a method to facilitate the accurate interpretation of fluid thermodynamic property data from those tables. There are two parts to this paper. The first part of the paper shows how efficient and usable property tables were generated, with the minimum number of data points, using an aerospace industry standard property package. The second part describes an innovative interpolation technique that has been developed to properly obtain thermodynamic properties near the saturated liquid and saturated vapor lines.

  15. Thermodynamic properties for polycyclic systems by non-calorimetric methods

    NASA Astrophysics Data System (ADS)

    Steele, W. V.; Chirico, R. D.; Klots, T. D.

    1993-03-01

    A detailed vibrational spectroscopic study of furan, pyrrole, and thiophene has been completed. These compounds form part of the base of five-membered ring systems on which the rest of the research program will be built. Several methyl-substituted derivatives were also studied. The results will be used to confirm the model for alkyl-substitution in the ring systems. Gas-phase spectra and fundamental frequency assignments were completed for 2,3- and 2,5-dihydrofuran. Those compounds initiate work on ring-puckering within the research program. A paper describing the need for third virial estimation, when using the virial equation of state to derive thermodynamic properties at pressures greater than 1 bar was completed.

  16. Thermodynamic properties for polycyclic systems by non-calorimetric methods

    SciTech Connect

    Steele, W.V.; Chirico, R.D.; Klots, T.D.

    1993-03-01

    A detailed vibrational spectroscopic study of furan, pyrrole, and thiophene has been completed. These compounds form part of the base of five-membered ring systems on which the rest of the research program will be built Several methyl-substituted derivatives were also studied. The results will be used to confirm the model for alkyl- substitution in the ring systems. Gas-phase spectra and fundamental- frequency assignments were completed for 2,3- and 2,5-dihydrofuran. Those compounds initiate work on ring-puckering within the research program. A paper describing the need for third virial estimation, when using the virial equation of state to derive thermodynamic properties at pressures greater than 1 bar was completed.

  17. Thermodynamics properties of the dark energy in loop quantum cosmology

    E-print Network

    Kui Xiao; Jian-Yang Zhu

    2010-06-28

    Considering an arbitrary, varying equation of the state parameter, the thermodynamic properties of the dark energy fluid in a semiclassical loop quantum cosmology scenario, which we consider the inverse volume modification, is studied. The equation of the state parameters are corrected as a semiclassical one during considering the effective behavior. Assuming that the apparent horizon has Hawking temperature, the modified entropy-area relation is obtained, we find that this relation is different from the one which is obtained by considering the holonomy correction. Considering the dark energy is a thermal equilibrium fluid, we get the expressions for modified temperature, chemical potential and entropy. The temperature, chemical potential and entropy are well-defined in the semiclassical regions.

  18. Thermodynamic properties of asymptotically Reissner-Nordstrom black holes

    E-print Network

    Seyed Hossein Hendi

    2014-05-24

    Motivated by possible relation between Born-Infeld type nonlinear electrodynamics and an effective low-energy action of open string theory, asymptotically Reissner--Nordstrom black holes whose electric field is described by a nonlinear electrodynamics (NLED) are studied. We take into account a four dimensional topological static black hole ansatz and solve the field equations, exactly, in terms of the NLED as a matter field. The main goal of this paper is investigation of thermodynamic properties of the obtained black holes. Moreover, we calculate the heat capacity and find that the nonlinearity affects the minimum size of stable black holes. We also use Legendre-invariant metric proposed by Quevedo to obtain scalar curvature divergences. We find that the singularities of the Ricci scalar in Geometrothermodynamics (GTD) method take place at the Davies points.

  19. Note on electrical and thermodynamic properties of isolated horizons

    NASA Astrophysics Data System (ADS)

    Chen, Gerui; Wu, Xiaoning; Gao, Sijie

    2015-03-01

    The electrical laws and Carnot cycle of isolated horizons (IH) are investigated in this paper. We establish Ohm's law and Joule's law of isolated horizons and find that the conceptual picture of black holes (membrane paradigm) can also apply to this kind of quasilocal black holes. We also investigate the geometrical properties near nonrotating IHs and find that under the first-order approximation of r , there exist a Killing vector ??u/ and a Hamiltonian conjugate to it, so this vector can be thought to be a physical observer. We calculate the energy as measured at infinity of a particle at rest outside a nonrotating IH, and we use this result to construct a reversible Carnot cycle with the isolated horizon as a cold reservoir, which confirms the thermodynamic nature of isolated horizons.

  20. Thermodynamic properties of chlorite and berthierine derived from calorimetric measurements

    NASA Astrophysics Data System (ADS)

    Blanc, Philippe; Gailhanou, Hélène; Rogez, Jacques; Mikaelian, Georges; Kawaji, Hitoshi; Warmont, Fabienne; Gaboreau, Stéphane; Grangeon, Sylvain; Grenèche, Jean-Marc; Vieillard, Philippe; Fialips, Claire I.; Giffaut, Eric; Gaucher, Eric C.; Claret, F.

    2014-09-01

    In the context of the deep waste disposal, we have investigated the respective stabilities of two iron-bearing clay minerals: berthierine ISGS from Illinois [USA; (Al0.975FeIII0.182FeII1.422Mg0.157Li0.035Mn0.002)(Si1.332Al0.668)O5(OH)4] and chlorite CCa-2 from Flagstaff Hill, California [USA; (Si2.633Al1.367)(Al1.116FeIII0.215Mg2.952FeII1.712Mn0.012Ca0.011)O10(OH)8]. For berthierine, the complete thermodynamic dataset was determined at 1 bar and from 2 to 310 K, using calorimetric methods. The standard enthalpies of formation were obtained by solution-reaction calorimetry at 298.15 K, and the heat capacities were measured by heat-pulse calorimetry. For chlorite, the standard enthalpy of formation is measured by solution-reaction calorimetry at 298.15 K. This is completing the entropy and heat capacity obtained previously by Gailhanou et al. (Geochim Cosmochim Acta 73:4738-4749, 2009) between 2 and 520 K, by using low-temperature adiabatic calorimetry and differential scanning calorimetry. For both minerals, the standard entropies and the Gibbs free energies of formation at 298.15 K were then calculated. An assessment of the measured properties could be carried out with respect to literature data. Eventually, the thermodynamic dataset allowed realizing theoretical calculations concerning the berthierine to chlorite transition. The latter showed that, from a thermodynamic viewpoint, the main factor controlling this transition is probably the composition of the berthierine and chlorite minerals and the nature of the secondary minerals rather than temperature.

  1. Simplified curve fits for the thermodynamic properties of equilibrium air

    NASA Astrophysics Data System (ADS)

    Srinivasan, S.; Tannehill, J. C.; Weilmuenster, K. J.

    1986-06-01

    New improved curve fits for the thermodynamic properties of equilibrium air were developed. The curve fits are for p = p(e,rho), a = a(e,rho), T = T(e,rho), s = s(e,rho), T = T(p,rho), h = h(p,rho), rho = rho(p,s), e = e(p,s) and a = a(p,s). These curve fits can be readily incorporated into new or existing Computational Fluid Dynamics (CFD) codes if real-gas effects are desired. The curve fits were constructed using Grabau-type transition functions to model the thermodynamic surfaces in a piecewise manner. The accuracies and continuity of these curve fits are substantially improved over those of previous curve fits appearing in NASA CR-2470. These improvements were due to the incorporation of a small number of additional terms in the approximating polynomials and careful choices of the transition functions. The ranges of validity of the new curve fits are temperatures up to 25,000 K and densities from 10 to the minus 7th to 100 amagats (rho/rho sub 0).

  2. Simplified curve fits for the thermodynamic properties of equilibrium air

    NASA Technical Reports Server (NTRS)

    Srinivasan, S.; Tannehill, J. C.; Weilmuenster, K. J.

    1986-01-01

    New improved curve fits for the thermodynamic properties of equilibrium air were developed. The curve fits are for p = p(e,rho), a = a(e,rho), T = T(e,rho), s = s(e,rho), T = T(p,rho), h = h(p,rho), rho = rho(p,s), e = e(p,s) and a = a(p,s). These curve fits can be readily incorporated into new or existing Computational Fluid Dynamics (CFD) codes if real-gas effects are desired. The curve fits were constructed using Grabau-type transition functions to model the thermodynamic surfaces in a piecewise manner. The accuracies and continuity of these curve fits are substantially improved over those of previous curve fits appearing in NASA CR-2470. These improvements were due to the incorporation of a small number of additional terms in the approximating polynomials and careful choices of the transition functions. The ranges of validity of the new curve fits are temperatures up to 25,000 K and densities from 10 to the minus 7th to 100 amagats (rho/rho sub 0).

  3. Thermodynamic and transport properties of superconducting Mg10B2.

    PubMed

    Finnemore, D K; Ostenson, J E; Bud'ko, S L; Lapertot, G; Canfield, P C

    2001-03-12

    Transport and thermodynamic properties of a sintered pellet of the newly discovered MgB2 superconductor have been measured to determine the characteristic critical magnetic fields and critical current densities. Both resistive transition and magnetization data give similar values of the upper critical field, Hc2, with magnetization data giving dHc2/dT = 0.44 T/K at the transition temperature of Tc = 40.2 K. Close to the transition temperature, magnetization curves are thermodynamically reversible, but at low temperatures the trapped flux can be on the order of 1 T. The value of dHc/dT at Tc is estimated to be about 12 mT/K, a value similar to classical superconductors like Sn. Hence, the Ginzburg-Landau parameter kappa approximately 26. Estimates of the critical supercurrent density, Jc, using hysteresis loops and the Bean model, give critical current densities on the order of 10(5) A/cm2. Hence the supercurrent coupling through the grain boundaries is comparable to intermetallics like Nb3Sn. PMID:11289944

  4. Non-BCS thermodynamic properties of H2 S superconductor

    NASA Astrophysics Data System (ADS)

    Durajski, Artur P.; Szcze&¸sacute; niak, Rados?aw; Li, Yinwei

    2015-08-01

    The present paper determines the thermodynamic properties of the superconducting state in the H2S compound. The values of the pressure from 130 GPa to 180 GPa were taken into consideration. The calculations were performed in the framework of the Eliashberg formalism. In the first step, the experimental course of the dependence of the critical temperature on the pressure was reproduced: TC ? < 31, 88 > K, whereas the Coulomb pseudopotential equal to 0.15 was adopted. Next, the following quantities were calculated: the order parameter at the temperature of zero Kelvin (? (0)), the specific heat jump at the critical temperature (?C (TC) ?CS (TC) -CN (TC)), and the thermodynamic critical field (HC (0)). It was found that the values of the dimensionless ratios: R? ? 2 ? (0) /kBTC , RC ? ?C(TC) /CN (TC) , and RH ?TCCN (TC) / HC2(0) deviate from the predictions of the BCS theory: R? ? < 3.64, 4.16 > , RC ? < 1.59, 2.24 > , and RH ? < 0.144, 0.163 > . Generalizing the results on the whole family of the HnS -type compounds, it was shown that the maximum value of the critical temperature can be equal to ˜290 K, while R?,RC and RH adopt the following values: 6.53, 3.99, and 0.093, respectively.

  5. The thermodynamic properties of hydrated -Al2O3 nanoparticles

    SciTech Connect

    Spencer, Elinor; Huang, Baiyu; Parker, Stewart F.; Kolesnikov, Alexander I; Ross, Dr. Nancy; Woodfield, Brian

    2013-01-01

    In this paper we report a combined calorimetric and inelastic neutron scattering (INS) study of hydrated -Al2O3 ( -alumina) nanoparticles. These complementary techniques have enabled a comprehensive evaluation of the thermodynamic properties of this technological and industrially important metal oxide to be achieved. The isobaric heat capacity (Cp) data presented herein provide further critical insights into the much-debated chemical composition of -alumina nanoparticles. Furthermore, the isochoric heat capacity (Cv) of the surface water, which is so essential to the stability of all metal-oxides at the nanoscale, has been extracted from the high-resolution INS data and differs significantly from that of ice Ih due to the dominating influence of strong surface-water interactions. This study also encompassed the analysis of four -alumina samples with differing pore diameters [4.5 (1), 13.8 (2), 17.9 (3), and 27.2 nm (4)], and the results obtained allow us to unambiguously conclude that the water content and pore size have no influence on the thermodynamic behaviour of hydrated -alumina nanoparticles.

  6. Electronic, mechanical, and thermodynamic properties of americium dioxide

    NASA Astrophysics Data System (ADS)

    Lu, Yong; Yang, Yu; Zheng, Fawei; Wang, Bao-Tian; Zhang, Ping

    2013-10-01

    By performing density functional theory (DFT) +U calculations, we systematically study the electronic, mechanical, tensile, and thermodynamic properties of AmO2. It is found that the chemical bonding character in AmO2 is similar to that in PuO2, with smaller charge transfer and stronger covalent interactions between americium and oxygen atoms. The stress-strain relationship of AmO2 is examined along the three low-index directions, showing that the [1 0 0] and [1 1 1] directions are the strongest and weakest tensile directions, respectively, but the theoretical tensile strengths of AmO2 are smaller than those of PuO2. The phonon dispersion curves of AmO2 are calculated and the heat capacities as well as lattice expansion curve are subsequently determined. The lattice thermal conductivity of AmO2 is further evaluated and compared with attainable experiments. Our present work integrally reveals various physical properties of AmO2 and can be referenced for technological applications of AmO2 based materials.

  7. Ideal gas thermodynamic properties for the phenyl, phenoxy, and o-biphenyl radicals

    NASA Technical Reports Server (NTRS)

    Burcat, A.; Zeleznik, F. J.; Mcbride, B. J.

    1985-01-01

    Ideal gas thermodynamic properties of the phenyl and o-biphenyl radicals, their deuterated analogs and the phenoxy radical were calculated to 5000 K using estimated vibrational frequencies and structures. The ideal gas thermodynamic properties of benzene, biphenyl, their deuterated analogs and phenyl were also calculated.

  8. Two-dimensional core-softened model with water like properties. Study by thermodynamic perturbation theory

    E-print Network

    T. Urbic

    2013-12-16

    Thermodynamic properties of the particles interacting through smooth version of Stell-Hemmer interaction were studied using Wertheim's thermodynamic perturbation theory. The temperature dependence of molar volume, heat capacity, isothermal compressibility and thermal expansion coefficient at constant pressure for different number of bonding sites on particle were evaluated. The model showed water-like anomalies for all evaluated quantities, but thermodynamic perturbation theory does not properly predict the dependence of these properties at a fixed number of bonding points.

  9. Thermodynamic properties of a suitable working fluid mixture for absorption heat pumps

    NASA Astrophysics Data System (ADS)

    Eichholz, H. D.; Schulz, S.

    1982-04-01

    An absorption heat pump process was considered with reference to thermodynamic properties of methanol lithium bromide as a working fluid. The process was optimized for operating conditions and the binary mixture used. All available thermodynamic data of mixture properties were collected. They were then complemented by vapor-liquid equilibrium measurements and heat of mixing experiments with the result of a theoretical correlation. By a critical selection of properties, the binary mixture CH30H LiBr was qualified as a heat pump working fluid. In addition, thermodynamic properties of methanol are derived by a fundamental equation.

  10. SPECIES - EVALUATING THERMODYNAMIC PROPERTIES, TRANSPORT PROPERTIES & EQUILIBRIUM CONSTANTS OF AN 11-SPECIES AIR MODEL

    NASA Technical Reports Server (NTRS)

    Thompson, R. A.

    1994-01-01

    Accurate numerical prediction of high-temperature, chemically reacting flowfields requires a knowledge of the physical properties and reaction kinetics for the species involved in the reacting gas mixture. Assuming an 11-species air model at temperatures below 30,000 degrees Kelvin, SPECIES (Computer Codes for the Evaluation of Thermodynamic Properties, Transport Properties, and Equilibrium Constants of an 11-Species Air Model) computes values for the species thermodynamic and transport properties, diffusion coefficients and collision cross sections for any combination of the eleven species, and reaction rates for the twenty reactions normally occurring. The species represented in the model are diatomic nitrogen, diatomic oxygen, atomic nitrogen, atomic oxygen, nitric oxide, ionized nitric oxide, the free electron, ionized atomic nitrogen, ionized atomic oxygen, ionized diatomic nitrogen, and ionized diatomic oxygen. Sixteen subroutines compute the following properties for both a single species, interaction pair, or reaction, and an array of all species, pairs, or reactions: species specific heat and static enthalpy, species viscosity, species frozen thermal conductivity, diffusion coefficient, collision cross section (OMEGA 1,1), collision cross section (OMEGA 2,2), collision cross section ratio, and equilibrium constant. The program uses least squares polynomial curve-fits of the most accurate data believed available to provide the requested values more quickly than is possible with table look-up methods. The subroutines for computing transport coefficients and collision cross sections use additional code to correct for any electron pressure when working with ionic species. SPECIES was developed on a SUN 3/280 computer running the SunOS 3.5 operating system. It is written in standard FORTRAN 77 for use on any machine, and requires roughly 92K memory. The standard distribution medium for SPECIES is a 5.25 inch 360K MS-DOS format diskette. The contents of the diskettes are compressed using the PKWARE archiving tools. The utility to unarchive the files, PKUNZIP.EXE, is included. This program was last updated in 1991. SUN and SunOS are registered trademarks of Sun Microsystems, Inc.

  11. Investigation of thermodynamic properties of metal-oxide catalysts

    NASA Astrophysics Data System (ADS)

    Shah, Parag Rasiklal

    An apparatus for Coulometric Titration was developed and used to measure the redox isotherms (i.e. oxygen fugacity P(O2) vs oxygen stoichiometry) of ceria-zirconia solid solutions, mixed oxides of vanadia, and vanadia supported on ZrO2. This data was used to correlate the redox thermodynamics of these oxides to their structure and catalytic properties. From the redox isotherms measured between 873 K and 973 K, the differential enthalpies of oxidation (DeltaH) for Ce0.81Zr0.19O 2.0 and Ce0.25Zr0.75O2.0 were determined, and they were found to be independent of extent of reduction or composition of the solid solution. They were also lower than DeltaH for ceria, which explains the better redox properties of ceria-zirconia solid solutions. The oxidation was driven by entropy in the low reduction region, and a structural model was proposed to explain the observed entropy effects. Redox isotherms were also measured for a number of bulk vanadates between 823 K and 973 K. DeltaG, DeltaH and DeltaS were reported for V 2O5, Mg3(VO4)2, CeVO 4 and ZrV2O7 along with DeltaG values for AlVO 4, LaVO4, CrVO4. V2O5 and ZrV2O7, which were the only oxides having V-O-V bonds, showed a two-step transition of vanadium for V+3?V +4 and V+4?V+5 equilibrium in the redox isotherms. The other oxides, all of which have only M-O-V (M=cation other than V), showed a direct one-step transition, V+3?V +5. The nature of the M-atom also influenced the P(O2) at which the V+3?V+5 transition occurs. Redox isotherms at 748 K were measured for vanadia supported on ZrO 2; with two different vanadia loadings corresponding to isolated vanadyls and polymeric vanadyls. The isotherm for the sample with isolated vanadyls showed a single-step transition, similar to the one seen in bulk vanadates with M-O-V linkages, while no such one-step transition was observed in the isotherm of the other sample. To study the affect of the varying redox properties of the vanadium-based catalysts on oxidation rates, kinetic studies were performed for methanol and propane oxidation reactions on some of these catalysts. The results suggested that there was no effect of thermodynamic properties of these catalysts on the rates of these oxidation reactions.

  12. Thermodynamic and transport properties of air/water mixtures

    NASA Technical Reports Server (NTRS)

    Fessler, T. E.

    1981-01-01

    Subroutine WETAIR calculates properties at nearly 1,500 K and 4,500 atmospheres. Necessary inputs are assigned values of combinations of density, pressure, temperature, and entropy. Interpolation of property tables obtains dry air and water (steam) properties, and simple mixing laws calculate properties of air/water mixture. WETAIR is used to test gas turbine engines and components operating in relatively humid air. Program is written in SFTRAN and FORTRAN.

  13. Thermodynamic Properties of LiBr/H2O Solution

    NASA Astrophysics Data System (ADS)

    Murakami, Kazuhiko; Sato, Haruki; Watanabe, Koichi

    Although most of the absorption refrigeration/heat pump systems use LiBr/H2O solution for absorbent/refrigerant pair, there exist only a limited number of reliable sets of data on the bubble-point pressures of LiBr/H2O solution. The objective of the present study is to reveal the concentration and temperature dependence of bubble-point pressures of LiBr/H2O solution over a wide range of parameters so as to provide more precise set of thermodynamic property data for advanced design of the absorption refrigeration/heat pump equipments. A total of 44 bubble-point pressures have been measured along seven concentration isopleths of 20, 30, 40, 45, 50, 58 and 60 wt%LiBr solution which cover the range of temperatures 283-413 K and of pressures up to 300 kPa. The experimental uncertainties of temperature, pressure and concentration measurements were not greater than ±20mK, ±0.1 kPa and ±0.1wt%, respectively.

  14. Molecular Dynamics Simulation of Thermodynamic Properties in Uranium Dioxide

    SciTech Connect

    Wang, Xiangyu; Wu, Bin; Gao, Fei; Li, Xin; Sun, Xin; Khaleel, Mohammad A.; Akinlalu, Ademola V.; Liu, L.

    2014-03-01

    In the present study, we investigated the thermodynamic properties of uranium dioxide (UO2) by molecular dynamics (MD) simulations. As for solid UO2, the lattice parameter, density, and enthalpy obtained by MD simulations were in good agreement with existing experimental data and previous theoretical predictions. The calculated thermal conductivities matched the experiment results at the midtemperature range but were underestimated at very low and very high temperatures. The calculation results of mean square displacement represented the stability of uranium at all temperatures and the high mobility of oxygen toward 3000 K. By fitting the diffusivity constant of oxygen with the Vogel-Fulcher-Tamman law, we noticed a secondary phase transition near 2006.4 K, which can be identified as a ‘‘strong’’ to ‘‘fragile’’ supercooled liquid or glass phase transition in UO2. By fitting the oxygen diffusion constant with the Arrhenius equation, activation energies of 2.0 and 2.7 eV that we obtained were fairly close to the recommended values of 2.3 to 2.6 eV. Xiangyu Wang, Bin Wu, Fei Gao, Xin Li, Xin Sun, Mohammed A. Khaleel, Ademola V. Akinlalu and Li Liu

  15. Wüstite: electric, thermodynamic and optical properties of FeO

    NASA Astrophysics Data System (ADS)

    Schrettle, F.; Kant, Ch.; Lunkenheimer, P.; Mayr, F.; Deisenhofer, J.; Loidl, A.

    2012-05-01

    We report on a systematic optical investigation of wüstite. In addition, the sample under consideration, Fe0.93O, has been characterized in detail by electrical transport, dielectric, magnetic and thermodynamic measurements. From infrared reflectivity experiments, phonon properties, Drude-like conductivity contributions and electronic transitions have been systematically investigated. The phonon modes reveal a clear splitting below the antiferromagnetic ordering temperature, similar to observations in other transition-metal monoxides and in spinel compounds which have been explained in terms of a spin-driven Jahn-Teller effect. The electronic transitions can best be described assuming a crystal-field parameter Dq = 750 cm-1 and a spin-orbit coupling constant ? = 95 cm-1. A well defined crystal field excitation at low temperatures reveals significant broadening on increasing temperature with an overall transfer of optical weight into dc conductivity contributions. This fact seems to indicate a melting of the on-site excitation into a Drude behavior of delocalized charge carriers. The optical band gap in wüstite is close to 1.0 eV at room temperature. With decreasing temperature and passing the magnetic phase transition we have detected a strong blue shift of the correlation-induced band edge, which amounts to more than 15% and has been rarely observed in antiferromagnets.

  16. THERMODYNAMIC PROPERTIES OF SEA-SALTAEROSOLS A. C. Tridico and I. N. Tang

    E-print Network

    ,FL Oct. 14-18, 1996 ABSTRACT The thennodynamic properties of mixed salt microdropletsrepresentativeof sea-saltBNL- 63377 [Abstract] THERMODYNAMIC PROPERTIES OF SEA-SALTAEROSOLS A. C. Tridico and I. N. Tang, (he hygroscopic properties of aerosolparticles generated from filtered sea-water sampleswere studied

  17. Thermodynamic properties of UF sub 6 measured with a ballistic piston compressor

    NASA Technical Reports Server (NTRS)

    Sterritt, D. E.; Lalos, G. T.; Schneider, R. T.

    1973-01-01

    From experiments performed with a ballistic piston compressor, certain thermodynamic properties of uranium hexafluoride were investigated. Difficulties presented by the nonideal processes encountered in ballistic compressors are discussed and a computer code BCCC (Ballistic Compressor Computer Code) is developed to analyze the experimental data. The BCCC unfolds the thermodynamic properties of uranium hexafluoride from the helium-uranium hexafluoride mixture used as the test gas in the ballistic compressor. The thermodynamic properties deduced include the specific heat at constant volume, the ratio of specific heats for UF6, and the viscous coupling constant of helium-uranium hexafluoride mixtures.

  18. FORTRAN 4 computer program for calculation of thermodynamic and transport properties of complex chemical systems

    NASA Technical Reports Server (NTRS)

    Svehla, R. A.; Mcbride, B. J.

    1973-01-01

    A FORTRAN IV computer program for the calculation of the thermodynamic and transport properties of complex mixtures is described. The program has the capability of performing calculations such as:(1) chemical equilibrium for assigned thermodynamic states, (2) theoretical rocket performance for both equilibrium and frozen compositions during expansion, (3) incident and reflected shock properties, and (4) Chapman-Jouguet detonation properties. Condensed species, as well as gaseous species, are considered in the thermodynamic calculation; but only the gaseous species are considered in the transport calculations.

  19. Prediction of some thermodynamic properties of selected compounds of element 104

    SciTech Connect

    Johnson, E. ); Fricke, B. )

    1991-09-05

    A set of parameterized equations has been published by Bratsch and Lagowski for calculating thermodynamic properties of the lanthanides, actinides, element 104, and certain related elements. Since these equations were applied to element 104, new values for the first four ionization energies and radii of the ions of charge +1, +2, +3, and +4 have been calculated for this element. The parameterized equations are used here with these new values to calculate some thermodynamic properties of element 104.

  20. WETAIR: A computer code for calculating thermodynamic and transport properties of air-water mixtures

    NASA Technical Reports Server (NTRS)

    Fessler, T. E.

    1979-01-01

    A computer program subroutine, WETAIR, was developed to calculate the thermodynamic and transport properties of air water mixtures. It determines the thermodynamic state from assigned values of temperature and density, pressure and density, temperature and pressure, pressure and entropy, or pressure and enthalpy. The WETAIR calculates the properties of dry air and water (steam) by interpolating to obtain values from property tables. Then it uses simple mixing laws to calculate the properties of air water mixtures. Properties of mixtures with water contents below 40 percent (by mass) can be calculated at temperatures from 273.2 to 1497 K and pressures to 450 MN/sq m. Dry air properties can be calculated at temperatures as low as 150 K. Water properties can be calculated at temperatures to 1747 K and pressures to 100 MN/sq m. The WETAIR is available in both SFTRAN and FORTRAN.

  1. An Interpolation Method for Obtaining Thermodynamic Properties Near Saturated Liquid and Saturated Vapor Lines

    NASA Technical Reports Server (NTRS)

    Nguyen, Huy H.; Martin, Michael A.

    2003-01-01

    The availability and proper utilization of fluid properties is of fundamental importance in the process of mathematical modeling of propulsion systems. Real fluid properties provide the bridge between the realm of pure analytiis and empirical reality. The two most common approaches used to formulate thermodynamic properties of pure substances are fundamental (or characteristic) equations of state (Helmholtz and Gibbs functions) and a piecemeal approach that is described, for example, in Adebiyi and Russell (1992). This paper neither presents a different method to formulate thermodynamic properties of pure substances nor validates the aforementioned approaches. Rather its purpose is to present a method to be used to facilitate the accurate interpretation of fluid thermodynamic property data generated by existing property packages. There are two parts to this paper. The first part of the paper shows how efficient and usable property tables were generated, with the minimum number of data points, using an aerospace industry standard property package (based on fundamental equations of state approach). The second part describes an innovative interpolation technique that has been developed to properly obtain thermodynamic properties near the saturated liquid and saturated vapor lines.

  2. Thermodynamic and transport property modeling in super critical water

    E-print Network

    Kutney, Michael C. (Michael Charles)

    2005-01-01

    Supercritical water oxidation (SCWO) is a thermally-based, remediation and waste-treatment process that relies on unique property changes of water when water is heated and pressurized above its critical point. Above its ...

  3. Playing with Marbles: Structural and Thermodynamic Properties of Hard-Sphere Systems

    E-print Network

    Andrés Santos

    2013-10-21

    These lecture notes present an overview of equilibrium statistical mechanics of classical fluids, with special applications to the structural and thermodynamic properties of systems made of particles interacting via the hard-sphere potential or closely related model potentials. The exact statistical-mechanical properties of one-dimensional systems, the issue of thermodynamic (in)consistency among different routes in the context of several approximate theories, and the construction of analytical or semi-analytical approximations for the structural properties are also addressed.

  4. Playing with Marbles: Structural and Thermodynamic Properties of Hard-Sphere Systems

    E-print Network

    Santos, Andrés

    2013-01-01

    These lecture notes present an overview of equilibrium statistical mechanics of classical fluids, with special applications to the structural and thermodynamic properties of systems made of particles interacting via the hard-sphere potential or closely related model potentials. The exact statistical-mechanical properties of one-dimensional systems, the issue of thermodynamic (in)consistency among different routes in the context of several approximate theories, and the construction of analytical or semi-analytical approximations for the structural properties are also addressed.

  5. Microgravity effects on thermodynamic and kinetic properties of colloidal dispersions.

    PubMed

    Okubo, Tsuneo; Tsuchida, Akira

    2002-10-01

    Microgravity experiments on the physicochemical properties of colloidal dispersions reported hitherto have been reviewed. In microgravity, reliability and reproducibility of experimental data have been improved significantly by the elimination of convection in the suspension. Vanishment of the excess downward diffusion in microgravity has also produced a significant effect on properties of colloidal suspensions. For example, colloidal crystallization rates decreased in microgravity, whereas colloidal alloy crystallization rates increased. These results demonstrate the important role of the segregation effect in normal gravity. Colloidal silica formation reactions are retarded in microgravity, a phenomenon that is correlated deeply with disappearance of the downward diffusion of heavy products. PMID:12446323

  6. Thermodynamic properties of microbian populations on biological membranes

    E-print Network

    J. L. Silva-Acosta; R. Juárez-Maldonado

    2013-08-26

    In this work we to develop a general statistical mechanic formalism to study systems restricted to surfaces of revolution, these are a very well model to study the termodinamical properties of microbiological systems and macromolecules lies on biological membranes such as cellular well.

  7. Influence of pressure derivative of partition function on thermodynamic properties of non-local thermodynamic equilibrium thermal plasma

    NASA Astrophysics Data System (ADS)

    Singh, Gurpreet; Sharma, Rohit; Singh, Kuldip

    2015-09-01

    Thermodynamic properties (compressibility coefficient Z ? , specific heat at constant volume c v , adiabatic coefficient ? a , isentropic coefficient ? i s e n , and sound speed c s ) of non-local thermodynamic equilibrium hydrogen thermal plasma have been investigated for different values of pressure and non-equilibrium parameter ? (=Te/Th) in the electron temperature range from 6000 K to 60 000 K. In order to estimate the influence of pressure derivative of partition function on thermodynamic properties, two cases have been considered: (a) in which pressure derivative of partition function is taken into account in the expressions and (b) without pressure derivative of partition function in their expressions. Here, the case (b) represents expressions already available in literature. It has been observed that the temperature from which pressure derivative of partition function starts influencing a given thermodynamic property increases with increase of pressure and non-equilibrium parameter ?. Thermodynamic property in the case (a) is always greater than its value in the case (b) for compressibility coefficient and specific heat at constant volume, whereas for adiabatic coefficient, isentropic coefficient, and sound speed, its value in the case (a) is always less than its value in the case (b). For a given value of ?, the relationship of compressibility coefficient with degree of ionization depends upon pressure in the case (a), whereas it is independent of pressure in the case (b). Relative deviation between the two cases shows that the influence of pressure derivative of partition function is significantly large and increases with the augmentation of pressure and ? for compressibility coefficient, specific heat at constant volume, and adiabatic coefficient, whereas for isentropic coefficient and sound speed, it is marginal even at high values of pressure and non-equilibrium parameter ?.

  8. Thermodynamics and Ferroelectric Properties of KNbO3

    SciTech Connect

    Liang, Linyun; Li, Yulan; Chen , L.Q.; Hu, Shenyang Y.; Lu, Guang-Hong

    2009-11-15

    The Landau-Ginsburg-Devonshire (LGD) phenomenological theory is employed to model and predict the ferroelectric phase transitions and properties of single-domain potassium niobate (KNbO3). Based on the LGD theory and the experimental data of KNbO3 single crystal, an eighth-order polynomial of free energy function is proposed. The fitted coefficients are validated by comparing to a set of experimental measured values including phase transition temperatures, spontaneous polarization, dielectric constants, and lattice constants. The effects of hydrostatic pressure and external electric field on phase transition temperatures and piezoelectric coefficients are investigated. The free energy function may be used a phase-field modeling to predict ferroelectric domain structures and properties of KNbO3 bulk crystals and films by phase-field approach.

  9. Analytical description of thermodynamic properties of steam, water and the phase interface for use in CFD

    NASA Astrophysics Data System (ADS)

    Hrubý, Jan; Duška, Michal

    2014-03-01

    We present a system of analytical equations for computation of all thermodynamic properties of dry steam and liquid water (undesaturated, saturated and metastable supersaturated) and properties of the liquid-vapor phase interface. The form of the equations is such that it enables computation of all thermodynamic properties for independent variables directly related to the balanced quantities - total mass, liquid mass, energy, momenta. This makes it suitable for the solvers of fluid dynamics equations in the conservative form. Thermodynamic properties of dry steam and liquid water are formulated in terms of special thermodynamic potentials and all properties are obtained as analytical derivatives. For the surface tension, the IAPWS formula is used. The interfacial internal energy is derived from the surface tension and it is used in the energy balance. Unlike common models, the present one provides real (contrary to perfect gas approximation) properties of steam and water and reflects the energetic effects due to the surface tension. The equations are based on re-fitting the reference formulation IAPWS-95 and selected experimental data. The mathematical structure of the equations is optimized for fast computation.

  10. Computer codes for the evaluation of thermodynamic properties, transport properties, and equilibrium constants of an 11-species air model

    NASA Technical Reports Server (NTRS)

    Thompson, Richard A.; Lee, Kam-Pui; Gupta, Roop N.

    1990-01-01

    The computer codes developed provide data to 30000 K for the thermodynamic and transport properties of individual species and reaction rates for the prominent reactions occurring in an 11-species nonequilibrium air model. These properties and the reaction-rate data are computed through the use of curve-fit relations which are functions of temperature (and number density for the equilibrium constant). The curve fits were made using the most accurate data believed available. A detailed review and discussion of the sources and accuracy of the curve-fitted data used herein are given in NASA RP 1232.

  11. Rapid Computation of Thermodynamic Properties Over Multidimensional Nonbonded Parameter Spaces using Adaptive Multistate Reweighting

    E-print Network

    Naden, Levi N

    2015-01-01

    We show how thermodynamic properties of molecular models can be computed over a large, multidimensional parameter space by combining multistate reweighting analysis with a linear basis function approach. This approach reduces the computational cost to estimate thermodynamic properties from molecular simulations for over 130,000 tested parameter combinations from over a thousand CPU years to tens of CPU days. This speed increase is achieved primarily by computing the potential energy as a linear combination of basis functions, computed from either modified simulation code or as the difference of energy between two reference states, which can be done without any simulation code modification. The thermodynamic properties are then estimated with the Multistate Bennett Acceptance Ratio (MBAR) as a function of multiple model parameters without the need to define a priori how the states are connected by a pathway. Instead, we adaptively sample a set of points in parameter space to create mutual configuration space o...

  12. Thermodynamic properties of sophocarpine and oxysophocarpine alkaloids in aqueous glucose solutions

    NASA Astrophysics Data System (ADS)

    Li, Zongxiao; Zhao, Weiwei; Pu, Xiaohua

    2012-04-01

    Sophocarpine and oxysophocarpine's dissolution in aqueous glucose solutions were studied by a microcalorimetry method. The measured integral and differential heat of dissolution was used to build equations of the solute and the heat, so that dissolution thermodynamic equations, ?sol H m were achieved, which reveals the relationship between the substances structure and the thermodynamic properties. The current study provides theoretical bases for clinical applications of them.

  13. Electrolytes: transport properties and non-equilibrium thermodynamics

    SciTech Connect

    Miller, D.G.

    1980-12-01

    This paper presents a review on the application of non-equilibrium thermodynamics to transport in electrolyte solutions, and some recent experimental work and results for mutual diffusion in electrolyte solutions.

  14. Experimental verification of the thermodynamic properties for a jet-A fuel

    NASA Technical Reports Server (NTRS)

    Graciasalcedo, Carmen M.; Brabbs, Theodore A.; Mcbride, Bonnie J.

    1988-01-01

    Thermodynamic properties for a Jet-A fuel were determined by Shell Development Company in 1970 under a contract for NASA Lewis Research Center. The polynomial fit necessary to include Jet-A fuel (liquid and gaseous phases) in the library of thermodynamic properties of the NASA Lewis Chemical Equilibrium Program is calculated. To verify the thermodynamic data, the temperatures of mixtures of liquid Jet-A injected into a hot nitrogen stream were experimentally measured and compared to those calculated by the program. Iso-octane, a fuel for which the thermodynamic properties are well known, was used as a standard to calibrate the apparatus. The measured temperatures for the iso-octane/nitrogen mixtures reproduced the calculated temperatures except for a small loss due to the non-adiabatic behavior of the apparatus. The measurements for Jet-A were corrected for this heat loss and showed excellent agreement with the calculated temperatures. These experiments show that this process can be adequately described by the thermodynamic properties fitted for the Chemical Equilibrium Program.

  15. A quantum model for bending vibrations and thermodynamic properties of C3.

    NASA Technical Reports Server (NTRS)

    Hansen, C. F.; Pearson, W. E.

    1973-01-01

    The investigation reported was conducted to clarify the thermodynamic properties of C3 by further developing the limit to the partition function suggested by Strauss and Thiele (1967). A quantum solution for the energy levels of a quadratically perturbed square well potential is presented and the consistency of this limit with observed energy levels is established. In the process a more complete physical picture of the bending C3 molecules emerges. The values of entropy deduced from various measurements of graphite pressure are compared with this limit, and the thermodynamic properties predicted for the limiting case are evaluated.

  16. Thermodynamic Properties of Expanded Liquid Mercury in the Metal-Nonmetal Transition Range

    NASA Astrophysics Data System (ADS)

    Yao, Makoto; Endo, Hirohisa

    1982-03-01

    Simultaneous measurements of the density and electrical conductivity have been carried out for expanded liquid Hg in the temperature and pressure range up to 1500°C and up to 2200 bar. At densities below 10 g/cm3 the temperature coefficient of the conductivity at constant volume increases appreciably with decreasing density. Anomalous behaviours are found in the thermodynamic properties such as equation-of-state and isothermal compressibility when the metallic Hg is transformed to a nonmetallic state. Structural changes in the metal-nonmetal transition range are discussed in connection with the observed thermodynamic properties.

  17. Two-temperature thermodynamic and transport properties of SF6-Cu plasmas

    NASA Astrophysics Data System (ADS)

    Wu, Yi; Chen, Zhexin; yang, Fei; Cressault, Yann; Murphy, Anthony B.; Guo, Anxiang; Liu, Zirui; Rong, Mingzhe; Sun, Hao

    2015-10-01

    SF6 and Cu are widely adopted in electrical equipment as a dielectric medium and for conductive components, respectively. SF6-Cu plasmas are frequently formed, particularly in high-voltage circuit breaker arcs and fault current arcs, due to erosion of the Cu components. In this paper, calculated values of the thermodynamic and transport properties of plasmas in SF6-Cu mixtures are presented for both thermal equilibrium and non-equilibrium conditions. The composition is determined by the two-temperature Saha equation and Guldberg-Waage equation in the form derived by van de Sanden. The composition and the thermodynamic properties are evaluated through a classical statistical mechanics approach. For the transport coefficients, the simplified Chapman-Enskog method developed by Devoto, which decouples the electrons and heavy species, has been applied using the most recent collision integrals. The thermodynamic and transport properties are calculated for different electron temperatures (300-40?000 K), ratios of electron to heavy-species temperature (1-10), pressures (0.1-10 atm) and copper molar proportions (0-50%). It is found that deviations from thermal equilibrium strongly affect the thermodynamic and transport properties of the SF6-Cu plasmas. Further, the presence of copper has different effects on some of the properties for plasmas in and out of thermal equilibrium. The main reason for these changes is that dissociation reactions are delayed for non-thermal equilibrium plasmas, which in turn influences the ionization reactions that occur.

  18. An Equation of State for the Thermodynamic Properties of Cyclohexane

    SciTech Connect

    Zhou, Yong Liu, Jun; Penoncello, Steven G.; Lemmon, Eric W.

    2014-12-15

    An equation of state for cyclohexane has been developed using the Helmholtz energy as the fundamental property with independent variables of density and temperature. Multi-property fitting technology was used to fit the equation of state to data for p?T, heat capacities, sound speeds, virial coefficients, vapor pressures, and saturated densities. The equation of state was developed to conform to the Maxwell criteria for two-phase vapor-liquid equilibrium states, and is valid from the triple-point temperature to 700 K, with pressures up to 250 MPa and densities up to 10.3 mol?dm{sup ?3}. In general, the uncertainties (k = 2, indicating a level of confidence of 95%) in density for the equation of state are 0.1% (liquid and vapor) up to 500 K, and 0.2% above 500 K, with higher uncertainties within the critical region. Between 283 and 473 K with pressures lower than 30 MPa, the uncertainty is as low as 0.03% in density in the liquid phase. The uncertainties in the speed of sound are 0.2% between 283 and 323 K in the liquid, and 1% elsewhere. Other uncertainties are 0.05% in vapor pressure and 2% in heat capacities. The behavior of the equation of state is reasonable within the region of validity and at higher and lower temperatures and pressures. A detailed analysis has been performed in this article.

  19. Theoretical calculating the thermodynamic properties of solid sorbents for CO{sub 2} capture applications

    SciTech Connect

    Duan, Yuhua

    2012-11-02

    Since current technologies for capturing CO{sub 2} to fight global climate change are still too energy intensive, there is a critical need for development of new materials that can capture CO{sub 2} reversibly with acceptable energy costs. Accordingly, solid sorbents have been proposed to be used for CO{sub 2} capture applications through a reversible chemical transformation. By combining thermodynamic database mining with first principles density functional theory and phonon lattice dynamics calculations, a theoretical screening methodology to identify the most promising CO{sub 2} sorbent candidates from the vast array of possible solid materials has been proposed and validated. The calculated thermodynamic properties of different classes of solid materials versus temperature and pressure changes were further used to evaluate the equilibrium properties for the CO{sub 2} adsorption/desorption cycles. According to the requirements imposed by the pre- and post- combustion technologies and based on our calculated thermodynamic properties for the CO{sub 2} capture reactions by the solids of interest, we were able to screen only those solid materials for which lower capture energy costs are expected at the desired pressure and temperature conditions. Only those selected CO{sub 2} sorbent candidates were further considered for experimental validations. The ab initio thermodynamic technique has the advantage of identifying thermodynamic properties of CO{sub 2} capture reactions without any experimental input beyond crystallographic structural information of the solid phases involved. Such methodology not only can be used to search for good candidates from existing database of solid materials, but also can provide some guidelines for synthesis new materials. In this presentation, we first introduce our screening methodology and the results on a testing set of solids with known thermodynamic properties to validate our methodology. Then, by applying our computational method to several different kinds of solid systems, we demonstrate that our methodology can predict the useful information to help developing CO{sub 2} capture Technologies.

  20. Symmetry, Optical Properties and Thermodynamics of Neptunium(V) Complexes

    SciTech Connect

    Rao, Linfeng; Tian, Guoxin

    2009-12-21

    Recent results on the optical absorption and symmetry of the Np(V) complexes with dicarboxylate and diamide ligands are reviewed. The importance of recognizing the 'silent' feature of centrosymmetric Np(V) species in analyzing the absorption spectra and calculating the thermodynamic constants of Np(V) complexes is emphasized.

  1. Thermodynamic Properties for A Drop-in Refrigerant R-SP34E

    NASA Astrophysics Data System (ADS)

    Kayukawa, Yohei; Hondo, Takashi; Watanabe, Koichi

    Although a transition into several promising HFC alternative refrigerants and their mixtures from conventional CFC and/or HCFC refrigerants is steadily in progress, there still remains a niche to pursue a drop-in refrigerant in some limited engineering applications where the advantage of retrofitting can be emphasized.R-SP34E is one of such drop-in refrigerants to complement R-12 which is a ternary mixture refrigerant consisted of R-134a with minor fractions of propane and ethanol. In this paper, the fundamental thermodynamic properties such as VLE properties and gas-phase PVT properties of R-SP34E are presented. This paper reports the first sets of measured data including 7 dew-and bubble-point pressures and 73 gas-phase PVT properties in the extensive range of temperatures 300-380 K, pressures 0.1-5.2 MPa, and densities up to around the critical density, obtained by employing the Burnett apparatus. In order to complement and confirm the reliability of the measurements, thermodynamic models including a dew-point pressure correlation and a truncated virial equation of state were originally developed in this study. The models were confirmed to exhibit not only excellent reproducibility of the measurements but also the thermodynamic consistency regarding the temperature dependence of the second and third virial coefficients and derived properties such as specific heats or speed of sound. By presenting the reliable thermodynamic model, a systematic information about the thermodynamic properties of R-SP34E is provided in this paper.

  2. Thermodynamic scaling of dynamic properties of liquid crystals: Verifying the scaling parameters using a molecular model

    NASA Astrophysics Data System (ADS)

    Satoh, Katsuhiko

    2013-08-01

    The thermodynamic scaling of molecular dynamic properties of rotation and thermodynamic parameters in a nematic phase was investigated by a molecular dynamic simulation using the Gay-Berne potential. A master curve for the relaxation time of flip-flop motion was obtained using thermodynamic scaling, and the dynamic property could be solely expressed as a function of TV^{? _? }, where T and V are the temperature and volume, respectively. The scaling parameter ?? was in excellent agreement with the thermodynamic parameter ?, which is the logarithm of the slope of a line plotted for the temperature and volume at constant P2. This line was fairly linear, and as good as the line for p-azoxyanisole or using the highly ordered small cluster model. The equivalence relation between ? and ?? was compared with results obtained from the highly ordered small cluster model. The possibility of adapting the molecular model for the thermodynamic scaling of other dynamic rotational properties was also explored. The rotational diffusion constant and rotational viscosity coefficients, which were calculated using established theoretical and experimental expressions, were rescaled onto master curves with the same scaling parameters. The simulation illustrates the universal nature of the equivalence relation for liquid crystals.

  3. Thermodynamic scaling of dynamic properties of liquid crystals: verifying the scaling parameters using a molecular model.

    PubMed

    Satoh, Katsuhiko

    2013-08-28

    The thermodynamic scaling of molecular dynamic properties of rotation and thermodynamic parameters in a nematic phase was investigated by a molecular dynamic simulation using the Gay-Berne potential. A master curve for the relaxation time of flip-flop motion was obtained using thermodynamic scaling, and the dynamic property could be solely expressed as a function of TV(??) , where T and V are the temperature and volume, respectively. The scaling parameter ?? was in excellent agreement with the thermodynamic parameter ?, which is the logarithm of the slope of a line plotted for the temperature and volume at constant P2. This line was fairly linear, and as good as the line for p-azoxyanisole or using the highly ordered small cluster model. The equivalence relation between ? and ?(?) was compared with results obtained from the highly ordered small cluster model. The possibility of adapting the molecular model for the thermodynamic scaling of other dynamic rotational properties was also explored. The rotational diffusion constant and rotational viscosity coefficients, which were calculated using established theoretical and experimental expressions, were rescaled onto master curves with the same scaling parameters. The simulation illustrates the universal nature of the equivalence relation for liquid crystals. PMID:24007031

  4. Thermodynamic properties of uranium in gallium-aluminium based alloys

    NASA Astrophysics Data System (ADS)

    Volkovich, V. A.; Maltsev, D. S.; Yamshchikov, L. F.; Chukin, A. V.; Smolenski, V. V.; Novoselova, A. V.; Osipenko, A. G.

    2015-10-01

    Activity, activity coefficients and solubility of uranium was determined in gallium-aluminium alloys containing 1.6 (eutectic), 5 and 20 wt.% aluminium. Additionally, activity of uranium was determined in aluminium and Ga-Al alloys containing 0.014-20 wt.% Al. Experiments were performed up to 1073 K. Intermetallic compounds formed in the alloys were characterized by X-ray diffraction. Partial and excess thermodynamic functions of U in the studied alloys were calculated.

  5. Thermodynamic properties of the itinerant-boson ferromagnet

    SciTech Connect

    Tao Chengjun; Wang Peilin; Qin Jihong; Gu Qiang

    2008-10-01

    Thermodynamics of a spin-1 Bose gas with ferromagnetic interactions is investigated via the mean-field theory. It is apparently shown in the specific-heat curve that the system undergoes two phase transitions, the ferromagnetic transition and Bose-Einstein condensation, with the Curie point above the condensation temperature. Above the Curie point, the susceptibility fits the Curie-Weiss law perfectly. At a fixed temperature, the reciprocal susceptibility is also in a good linear relationship with the ferromagnetic interaction.

  6. The thermodynamic properties of Davydov-Scott's protein model in thermal bath

    E-print Network

    Sulaiman, A; Alatas, H; Handoko, L T; 10.1142/9789814335614_0072

    2011-01-01

    The thermodynamic properties of Davydov-Scott monomer contacting with thermal bath is investigated using Lindblad open quantum system formalism. The Lindblad equation is investigated through path integral method. It is found that the environmental effects contribute destructively to the specific heat, and large interaction between amide-I and amide-site is not preferred for a stable Davydov-Scott monomer.

  7. Thermoelectric and thermodynamic properties of half-Heulser alloy YPdSb from first principles calculations

    SciTech Connect

    Kong, Fanjie; Hu, Yanfei; Hou, Haijun; Liu, Yanhua; Wang, Baolin; Wang, Lili

    2012-12-15

    The structural, electronic, thermoelectric and thermodynamic properties of ternary half-Heusler compound YPdSb are investigated using the first principle calculations. It is found that YPdSb is an indirect semiconductor. The calculated band gap is 0.161 eV with spin-orbital coupling including and 0.235 eV without spin-orbital coupling including, respectively. The electronic transport properties are obtained via Boltzman transport theory. The predicted Seebeck coefficient is 240 {mu}V/K and the thermoelectric performance can be optimized by n-type doping at room temperature. Moreover, the lattice dynamical results regarding the phonon dispersion curves, phonon density of states and thermodynamic properties are reported. Thermodynamics (heat capacity and Debye temperature) as well as mean phonon free path and the thermal conductivity in a temperature range of 0-300 K are determined. - Graphical Abstract: (a) The dependence of the Seebeck coefficient on chemical potential at 300 K. (b) The dependence of the thermopower factor on chemical potential at 300 K. Highlights: Black-Right-Pointing-Pointer The Seebeck coefficient and the thermopower factor are calculated. Black-Right-Pointing-Pointer The lattice dynamics and thermodynamic properties are obtained.

  8. Levitation calorimetry. IV - The thermodynamic properties of liquid cobalt and palladium.

    NASA Technical Reports Server (NTRS)

    Treverton, J. A.; Margrave, J. L.

    1971-01-01

    Some of the thermodynamic properties of liquid cobalt and palladium investigated by means of levitation calorimetry are reported and discussed. The presented data include the specific heats and heats of fusion of the liquid metals, and the emissivities of the liquid metal surfaces.

  9. The Problem of Counting the Number of Molecules and Calculating Thermodynamic Properties.

    ERIC Educational Resources Information Center

    Torres, Luis Alfonso; And Others

    1995-01-01

    Presents an experimental approach to illustrate that the thermodynamic properties of a system can be considered as the average of mechanical variables. Discusses the Knudsen effusion method to count the number of molecules, vapor pressure, the piezoelectric effect, the experimental setup, and sample experimental results. (JRH)

  10. Hypothetical Thermodynamic Properties. Subcooled Vaporization Enthalpies and Vapor Pressures of Polyaromatic Hydrocarbons

    E-print Network

    Chickos, James S.

    Hypothetical Thermodynamic Properties. Subcooled Vaporization Enthalpies and Vapor Pressures and liquid vapor pressures from T ) 298.15 K to T ) 510 K of a series of polyaromatic hydrocarbons have been of a thermochemical cycle, and agreement is within the combined experimental uncertainties. Vapor pressures

  11. Hypothetical Thermodynamic Properties. Subcooled Vaporization Enthalpies and Vapor Pressures of Polyaromatic Heterocycles and Related Compounds

    E-print Network

    Chickos, James S.

    Hypothetical Thermodynamic Properties. Subcooled Vaporization Enthalpies and Vapor Pressures The vaporization enthalpies and vapor pressures of the liqiud phase from T ) 298.15 K to T ) 500 K of a series in the literature was measured on a hydrated form. Vapor pressures and normal boiling temperatures for the liquid

  12. Modeling of Thermodynamic Properties and Phase Equilibria for the Cu-Mg Binary System

    E-print Network

    Chen, Long-Qing

    Modeling of Thermodynamic Properties and Phase Equilibria for the Cu-Mg Binary System Shihuai Zhou (Submitted November 2, 2006) The phase equilibria associated with the binary Cu-Mg system are analyzed previously reported models of phase equilibria, our treatment provides better agreement with experimental

  13. Thermodynamic and mechanical properties of TiC from ab initio calculation

    SciTech Connect

    Dang, D. Y.; Fan, J. L.; Gong, H. R.

    2014-07-21

    The temperature-dependent thermodynamic and mechanical properties of TiC are systematically investigated by means of a combination of density-functional theory, quasi-harmonic approximation, and thermal electronic excitation. It is found that the quasi-harmonic Debye model should be pertinent to reflect thermodynamic properties of TiC, and the elastic properties of TiC decease almost linearly with the increase of temperature. Calculations also reveal that TiC possesses a pronounced directional pseudogap across the Fermi level, mainly due to the strong hybridization of Ti 3d and C 2p states. Moreover, the strong covalent bonding of TiC would be enhanced (reduced) with the decrease (increase) of temperature, while the change of volume (temperature) should have negligible effect on density of states at the Fermi level. The calculated results agree well with experimental observations in the literature.

  14. Performance of the thermodynamic properties models in ASPEN. [Freon 12 and Freon 22

    SciTech Connect

    Fish, L.W.; Evans, D.R.

    1982-01-01

    In the course of performing a number of analyses using ASPEN, the performance of the ASPEN models for computing thermodynamic properties has been observed. Pure-component properties for propane, isobutane, Freon 12 and Freon 22 and mixture properties for the propane-isobutane and the ethanol-water systems have been computed and the results compared with available data sources and with independent sources of computed properties. The built-in data regression system (DRS) of ASPEN was used to regress P-V-T and enthalpy departure data for isobutane to determine model-specific parameters. The extended Antoine vapor pressure parameters were calculated for Freon 12. The ethanol-water vapor-liquid equilibrium region was studied throughout the composition range for three isobaric data sets. Several activity coefficient models in ASPEN were fit to the data using various user-specified property routes.

  15. Thermodynamic Properties of Spherically-Symmetric, Uniformly-Accelerated Reference Frames

    E-print Network

    Chao-Guang Huang; Jia-Rui Sun

    2007-01-15

    We aim to study the thermodynamic properties of the spherically symmetric reference frames with uniform acceleration, including the spherically symmetric generalization of Rindler reference frame and the new kind of uniformly accelerated reference frame. We find that, unlike the general studies about the horizon thermodynamics, one cannot obtain the laws of thermodynamics for their horizons in the usual approaches, despite that one can formally define an area entropy (Bekenstein-Hawking entropy). In fact, the common horizon for a set of uniformly accelerated observers is not always exist, even though the Hawking-Unruh temperature is still well-defined. This result indicates that the Hawking-Unruh temperature is only a kinematic effect, to gain the laws of thermodynamics for the horizon, one needs the help of dynamics. Our result is in accordance with those from the various studies about the acoustic black holes.

  16. Metastable Solution Thermodynamic Properties and Crystal Growth Kinetics

    NASA Technical Reports Server (NTRS)

    Kim, Soojin; Myerson, Allan S.

    1996-01-01

    The crystal growth rates of NH4H2PO4, KH2PO4, (NH4)2SO4, KAl(SO4)2 central dot 12H2O, NaCl, and glycine and the nucleation rates of KBr, KCl, NaBr central dot 2H2O, (NH4)2Cl, and (NH4)2SO4 were expressed in terms of the fundamental driving force of crystallization calculated from the activity of supersaturated solutions. The kinetic parameters were compared with those from the commonly used kinetic expression based on the concentration difference. From the viewpoint of thermodynamics, rate expressions based on the chemical potential difference provide accurate kinetic representation over a broad range of supersaturation. The rates estimated using the expression based on the concentration difference coincide with the true rates of crystallization only in the concentration range of low supersaturation and deviate from the true kinetics as the supersaturation increases.

  17. Thermodynamic properties of some metal oxide-zirconia systems

    NASA Technical Reports Server (NTRS)

    Jacobson, Nathan S.

    1989-01-01

    Metal oxide-zirconia systems are a potential class of materials for use as structural materials at temperatures above 1900 K. These materials must have no destructive phase changes and low vapor pressures. Both alkaline earth oxide (MgO, CaO, SrO, and BaO)-zirconia and some rare earth oxide (Y2O3, Sc2O3, La2O3, CeO2, Sm2O3, Gd2O3, Yb2O3, Dy2O3, Ho2O3, and Er2O3)-zirconia system are examined. For each system, the phase diagram is discussed and the vapor pressure for each vapor species is calculated via a free energy minimization procedure. The available thermodynamic literature on each system is also surveyed. Some of the systems look promising for high temperature structural materials.

  18. Thermodynamic properties of mesoscale convective systems observed during BAMEX

    SciTech Connect

    Correia, James; Arritt, R.

    2008-11-01

    Dropsonde observations from the Bow-echo and Mesoscale convective vortex EXperiment (BAMEX) are used to document the spatio-temporal variability of temperature, moisture and wind within mesoscale convective systems (MCSs). Onion type sounding structures are found throughout the stratiform region of MCSs but the temperature and moisture variability is large. Composite soundings were constructed and statistics of thermodynamic variability were generated within each sub-region of the MCS. The calculated air vertical velocity helped identify subsaturated downdrafts. We found that lapse rates within the cold pool varied markedly throughout the MCS. Layered wet bulb potential temperature profiles seem to indicate that air within the lowest several km comes from a variety of source regions. We also found that lapse rate transitions across the 0 C level were more common than isothermal, melting layers. We discuss the implications these findings have and how they can be used to validate future high resolution numerical simulations of MCSs.

  19. Dynamics and thermodynamic properties of CXCL7 chemokine.

    PubMed

    Herring, Charles A; Singer, Christopher M; Ermakova, Elena A; Khairutdinov, Bulat I; Zuev, Yuriy F; Jacobs, Donald J; Nesmelova, Irina V

    2015-11-01

    Chemokines form a family of signaling proteins mainly responsible for directing the traffic of leukocytes, where their biological activity can be modulated by their oligomerization state. We characterize the dynamics and thermodynamic stability of monomer and homodimer structures of CXCL7, one of the most abundant platelet chemokines, using experimental methods that include circular dichroism (CD) and nuclear magnetic resonance (NMR) spectroscopy, and computational methods that include the anisotropic network model (ANM), molecular dynamics (MD) simulations and the distance constraint model (DCM). A consistent picture emerges for the effects of dimerization and Cys5-Cys31 and Cys7-Cys47 disulfide bonds formation. The presence of disulfide bonds is not critical for maintaining structural stability in the monomer or dimer, but the monomer is destabilized more than the dimer upon removal of disulfide bonds. Disulfide bonds play a key role in shaping the characteristics of native state dynamics. The combined analysis shows that upon dimerization flexibly correlated motions are induced between the 30s and 50s loop within each monomer and across the dimer interface. Interestingly, the greatest gain in flexibility upon dimerization occurs when both disulfide bonds are present, and the homodimer is least stable relative to its two monomers. These results suggest that the highly conserved disulfide bonds in chemokines facilitate a structural mechanism that is tuned to optimally distinguish functional characteristics between monomer and dimer. Proteins 2015; 83:1987-2007. © 2015 Wiley Periodicals, Inc. PMID:26297927

  20. Thermodynamic properties by non-calorimetric methods. Progress report, August 1, 1988--July 31, 1989

    SciTech Connect

    Steele, W.V.; Chirico, R.D.; Collier, W.B.; Strube, M.M. |

    1989-12-31

    This three year research program provides a valuable complement to the experimental programs currently in progress at NIPER for the Advanced Research and Technology Development (AR and TD) and Advanced Exploration and Process Technology (AEPT) divisions of the Department of Energy. These experimental programs are focused on the calorimetric determination of thermodynamic properties of key polynuclear heteroatom-containing aromatic molecules. This project for the Office of Energy Research focuses on the non-calorimetric determination of thermodynamic properties through the extension of existing correlation methodologies and through molecular spectroscopy with statistical mechanics. The paper discusses progress in three areas: (1) Improvement of thermochemical and thermophysical property predictions via enhancement of group-contribution methods using two approaches, namely, development and improvement of group-contribution parameters via correlations involving the expanded modern thermodynamics data base and development of group-contribution parameters via molecular spectroscopy and statistical mechanics of key monocyclic organic compounds; (2) Molecular spectroscopy and statistical mechanics: equipment development and developments in interpretation and assignment of spectra; and (3) Thermophysical property correlations.

  1. Thermodynamic properties of the 2+1-dimensional Dirac fermions with broken time-reversal symmetry

    NASA Astrophysics Data System (ADS)

    Sharapov, S. G.

    2015-09-01

    We study the thermodynamic properties of the two-component 2+1-dimensional massive Dirac fermions in an external magnetic field. The broken time-reversal symmetry results in the presence of a linear in the magnetic field part of the thermodynamic potential, while in the famous problem of Landau diamagnetism the leading field dependent term is quadratic in the field. Accordingly, the leading term of the explicitly calculated magnetization is anomalous, viz it is independent of the strength of the magnetic field. The St?eda formula is employed to describe how the anomalous magnetization is related to the anomalous Hall effect.

  2. Thermodynamic, structural and surface properties in Sn-Zn melt at 750 K

    NASA Astrophysics Data System (ADS)

    Singh, B. P.; Koirala, R. P.; Jha, I. S.; Adhikari, D.

    2015-09-01

    Thermodynamic, microscopic and surface properties of liquid Sn-Zn alloys at 750 K are reviewed in the framework of different statistical mechanical models. Flory's model and quasi-chemical approximation (QCA) have been considered to deduce information on the concentration dependence of the thermodynamic and structural properties. The size-dependent atomic interaction has got special attention in Flory's model, while in QCA the atomic interaction leading to the formation of like-atom clusters is assumed. Both models predict almost the same value of the interaction energy parameter in the Sn-Zn alloys, and it is found to be temperature dependent. The asymmetry in the thermodynamic properties of the alloys is explained to a great extent, and the analysis of the microscopic properties suggests that the Sn-Zn alloys are weakly segregating in nature throughout the whole range of the composition. Meanwhile, the validity of these models in describing the thermodynamic behaviour of the alloys is also examined. QCA is found to be more appropriate choice for the study of the energetics of the Sn-Zn alloys at 750 K. The comparative analysis of the surface properties under different assumptions reveals that self-associating mixture method better explains the surface behaviour in the alloys. The study indicates nonlinear variation in the concentration dependence of both the surface concentration and the surface tension of the alloys. The surface tension is found to increase with increase in Zn concentration, and the surface of the alloys is enriched with Sn atoms which segregate to the surface.

  3. Interactive FORTRAN IV computer programs for the thermodynamic and transport properties of selected cryogens (fluids pack)

    NASA Technical Reports Server (NTRS)

    Mccarty, R. D.

    1980-01-01

    The thermodynamic and transport properties of selected cryogens had programmed into a series of computer routines. Input variables are any two of P, rho or T in the single phase regions and either P or T for the saturated liquid or vapor state. The output is pressure, density, temperature, entropy, enthalpy for all of the fluids and in most cases specific heat capacity and speed of sound. Viscosity and thermal conductivity are also given for most of the fluids. The programs are designed for access by remote terminal; however, they have been written in a modular form to allow the user to select either specific fluids or specific properties for particular needs. The program includes properties for hydrogen, helium, neon, nitrogen, oxygen, argon, and methane. The programs include properties for gaseous and liquid states usually from the triple point to some upper limit of pressure and temperature which varies from fluid to fluid.

  4. Characterisation of the surface thermodynamic properties of cement components by inverse gas chromatography at infinite dilution

    SciTech Connect

    Perruchot, Christian; Chehimi, Mohamed M.; Vaulay, Marie-Josephe; Benzarti, Karim . E-mail: benzarti@lcpc.fr

    2006-02-15

    The surface thermodynamic properties of three main inorganic compounds formed during hydration of Portland cement: calcium hydroxide (Ca(OH){sub 2}), ettringite (3CaO.Al{sub 2}O{sub 3}.3CaSO{sub 4}.32H{sub 2}O) and calcium-silicate-hydrates (C-S-H), respectively, and one mineral filler: calcium carbonate (CaCO{sub 3}), have been characterised by inverse gas chromatography at infinite dilution (IGC-ID) at 35 deg. C. The thermodynamic properties have been investigated using a wide range of non-polar (n-alkane series), Lewis acidic (CH{sub 2}Cl{sub 2} and CHCl{sub 3}), Lewis basic (diethyl ether) and aromatic (benzene) and n-alkene series molecular probes, respectively. The tested samples are fairly high surface energy materials as judged by the high dispersive contribution to the total surface energy (the dispersive components {gamma} {sub s} {sup d} range from 45.6 up to 236.2 mJ m{sup -2} at 35 deg. C) and exhibit amphoteric properties, with a predominant acidic character. In the case of hydrated components (i.e. ettringite and C-S-H), the surface thermodynamic properties have been determined at various temperatures (from 35 up to 120 deg. C) in order to examine the influence of the water content. The changes of both dispersive and specific components clearly demonstrate that the material surface properties are activated with temperature. The changes in the acid-base properties are correlated with the extent of the overall water loss induced by the thermal treatment as demonstrated by thermogravimetric analysis (TGA). The elemental surface composition of these compounds has been determined by X-ray photoelectron spectroscopy (XPS)

  5. Thermodynamic properties of liquid Au–Cu–Sn alloys determined from electromotive force measurements

    PubMed Central

    Guo, Zhongnan; Hindler, Michael; Yuan, Wenxia; Mikula, Adolf

    2011-01-01

    The thermodynamic properties of the ternary Au–Cu–Sn system were determined with the electromotive force (EMF) method using a liquid electrolyte. Three different cross-sections with constant Au:Cu ratios of 3:1, 1:1, and 1:3 were applied to measure the thermodynamic properties of the ternary system in the temperature range between the liquidus temperature of the alloys and 1023 K. The partial free energies of Sn in liquid Au–Cu–Sn alloys were obtained from EMF data. The integral Gibbs free energy and the integral enthalpy at 900 K were calculated by Gibbs–Duhem integration. The ternary interaction parameters were evaluated using the Redlich–Kister–Muggianu polynomial. PMID:22039311

  6. Effect of Dextran 70 on the thermodynamic and structural properties of proteins.

    PubMed

    Sharma, Gurumayum Suraj; Mittal, Shruti; Singh, Laishram Rajendrakumar

    2015-08-01

    Biological macromolecules are known to evolve and function under crowded intracellular environments that comprises of a wealth of soluble and insoluble macromolecules like proteins, nucleic acids, ribosomes and carbohydrates etc. Crowded environment is known to result in altered biological properties including thermodynamic, structural and functional aspect of macromolecules as compared to the macromolecules present in our commonly used experimental dilute buffers. In this study, we have investigated the effect of Dextran 70 on the thermodynamic and structural properties of three different proteins (Ribonuclease-A, lysozyme and holo ?-lactalbumin) at different pH values. We discovered that Dextran 70 has a protein-independent effect in terms of protein stability and structure. PMID:25936502

  7. Numerical prediction of the thermodynamic properties of ternary Al-Ni-Hf alloys

    SciTech Connect

    Romanowska, Jolanta; Kotowski, S?awomir; Zagula-Yavorska, Maryana

    2014-10-06

    Thermodynamic properties of ternary Al-Hf-Ni system, such as {sup ex}G, ?{sub Al}, ?{sub Ni} and ?{sub Zr} at 1373K were predicted on the basis of thermodynamic properties of binary systems included in the investigated ternary system. The idea of predicting {sup ex}G values was regarded as the calculation of excess Gibbs energy values inside a certain area (a Gibbs triangle) unless all boundary conditions, that is values of {sup ex}G on all legs of the triangle are known. {sup ex}G and L{sub ijk} ternary interaction parameters in the Muggianu extension of the Redlich-Kister formalism are calculated numerically using Wolfram Mathematica 9 software.

  8. Phase transition and thermodynamic properties of beryllium telluride under high pressure

    NASA Astrophysics Data System (ADS)

    Guo, Zhi-Cheng; Luo, Fen; Zhang, Xiu-Lu; Liu, Cheng-An; Cai, Ling-Cang

    2015-04-01

    A theoretical investigation on structural, dynamical, phase diagram and thermodynamic properties of beryllium telluride (BeTe) under high pressure and temperature is presented in the framework of density functional theory. The calculated structural parameters of BeTe in both zinc blende (ZB) and nickel arsenide (NiAs) structures are in reasonable agreement with available experimental data and previous theoretical work. The phonon dispersion relations, dielectric tensor and Born effective charge are investigated within the density functional perturbation theory (DFPT). The investigation of the phase diagram indicated that the NiAs structure BeTe becomes stable at high pressure and temperature. Based on the quasiharmonic Debye model, the pressure and temperature dependences of bulk modulus, Grüneisen parameter, Debye temperature, specific heat and thermal expansion coefficient are all successfully obtained. We hope that the theoretical results reported here can give more insight into the structural and thermodynamic properties of other semiconductors at high temperature and pressure.

  9. Accuracy Based Generation of Thermodynamic Properties for Light Water in RELAP5-3D

    SciTech Connect

    Cliff B. Davis

    2010-09-01

    RELAP5-3D interpolates to obtain thermodynamic properties for use in its internal calculations. The accuracy of the interpolation was determined for the original steam tables currently used by the code. This accuracy evaluation showed that the original steam tables are generally detailed enough to allow reasonably accurate interpolations in most areas needed for typical analyses of nuclear reactors cooled by light water. However, there were some regions in which the original steam tables were judged to not provide acceptable accurate results. Revised steam tables were created that used a finer thermodynamic mesh between 4 and 21 MPa and 530 and 640 K. The revised steam tables solved most of the problems observed with the original steam tables. The accuracies of the original and revised steam tables were compared throughout the thermodynamic grid.

  10. Gibbs Paradox as Property of Observation, Proof of II. Principle of Thermodynamics

    NASA Astrophysics Data System (ADS)

    Hejna, Bohdan

    2010-11-01

    Our way to deal with the given topic is a connection of both the mathematical definitions of information entropies and their mutual relations within a system of stochastic quantities especially with thermodynamic entropies defined on an isolated system in which a realization of our (repeatable) observation is performed [it is a (cyclic) transformation of heat energy of an observed, measured system]. We use the information description to analyze Gibbs paradox reasoning it as a property of such observation, measuring of an (equilibrium) thermodynamic system. We state a logical proof of the II. P.T. as a derivation of relations among the entropies of a system of stochastic variables, realized physically, and, the Equivalence Principle of the I., II. and III. Principle of Thermodynamics is formulated.

  11. First-principles calculations of the thermodynamic properties of transuranium elements in a molten salt medium

    NASA Astrophysics Data System (ADS)

    Noh, Seunghyo; Kwak, Dohyun; Lee, Juseung; Kang, Joonhee; Han, Byungchan

    2014-03-01

    We utilized first-principles density-functional-theory (DFT) calculations to evaluate the thermodynamic feasibility of a pyroprocessing methodology for reducing the volume of high-level radioactive materials and recycling spent nuclear fuels. The thermodynamic properties of transuranium elements (Pu, Np and Cm) were obtained in electrochemical equilibrium with a LiCl-KCl molten salt as ionic phases and as adsorbates on a W(110) surface. To accomplish the goal, we rigorously calculated the double layer interface structures on an atomic resolution, on the thermodynamically most stable configurations on W(110) surfaces and the chemical activities of the transuranium elements for various coverages of those elements. Our results indicated that the electrodeposition process was very sensitive to the atomic level structures of Cl ions at the double-layer interface. Our studies are easily expandable to general electrochemical applications involving strong redox reactions of transition metals in non-aqueous solutions.

  12. Thermodynamic properties of nitrogen gas derived from measurements of sound speed. [for cryogenic wind tunnels

    NASA Technical Reports Server (NTRS)

    Younglove, B.; Mccarty, R. D.

    1979-01-01

    A virial equation of state for nitrogen was determined by use of newly measured speed-of-sound data and existing pressure-density-temperature data in a multiproperty-fitting technique. The experimental data taken were chosen to optimize the equation of state for a pressure range of 0 to 10 atm and for a temperature range of 60 to 350 K. Comparisons are made for thermodynamic properties calculated both from the new equation and from existing equations of state.

  13. Quartz: heat capacities from 340 to 1000 K and revised values for the thermodynamic properties.

    USGS Publications Warehouse

    Hemingway, B.S.

    1987-01-01

    New heat-capacity data for quartz have been measured over the T interval 340-1000 K by differential scanning calorimetry. The data were combined with recent heat-content and heat-capacity data to provide a significantly revised set of thermodynamic properties for alpha -quartz and to resolve the problem of disparate heat-content and heat-capacity data for alpha - and beta -quartz.-J.A.Z.

  14. Thermodynamic properties of hot nuclei within the self-consistent quasiparticle random-phase approximation

    SciTech Connect

    Hung, N. Quang; Dang, N. Dinh

    2010-10-15

    The thermodynamic properties of hot nuclei are described within the canonical and microcanonical ensemble approaches. These approaches are derived based on the solutions of the BCS and self-consistent quasiparticle random-phase approximation at zero temperature embedded into the canonical and microcanonical ensembles. The results obtained agree well with the recent data extracted from experimental level densities by the Oslo group for {sup 94}Mo, {sup 98}Mo, {sup 162}Dy, and {sup 172}Yb nuclei.

  15. Improved methods for calculating thermodynamic properties of magnetic systems using Wang-Landau density of states

    SciTech Connect

    Brown, Greg; Rusanu, Aurelian; Daene, Markus W; Nicholson, Don M; Eisenbach, Markus; Fidler, Jane L

    2011-01-01

    The Wang-Landau method [F. Wang and D. P. Landau, Phys. Rev. E 64, 056101 (2001)] is an efficient way to calculate the density of states (DOS) for magnetic systems, and the DOS can then be used to rapidly calculate the thermodynamic properties of the system. A technique is presented that uses the DOS for a simple Hamiltonian to create a stratified sample of configurations which are then used calculate a warped DOS for more realistic Hamiltonians. This technique is validated for classical models of bcc Fe with exchange interactions of increasing range, but its real value is using the DOS for a model Hamiltonian calculated on a workstation to select the stratified set of configurations whose energies can then be calculated for a density-functional Hamiltonian. The result is an efficient first-principles calculation of thermodynamic properties such as the specific heat and magnetic susceptibility. Another technique uses the sample configurations to calculate the parameters of a model exchange interaction using a least-squares approach. The thermodynamic properties can be subsequently evaluated using traditional Monte Carlo techniques for the model exchange interaction. Finally, a technique that uses the configurations to train a neural network to estimate the configuration energy is also discussed. This technique could potentially be useful in identifying the configurations most important in calculating the warped DOS. VC2011 American Institute of Physics. [doi:10.1063/1.3565413

  16. Pressure-Temperature Dependence of Thermodynamic Properties of Perovskite from First Principles

    NASA Astrophysics Data System (ADS)

    Abdollahi, Arash; Gholzan, Seyed Maghsoud

    2015-08-01

    First-principles calculations have been performed to obtain the thermodynamic properties of perovskite in a wide range of pressure (0 GPa to 30 GPa) and temperature (0 K to 1400 K). Calculations have been performed by using the pseudo-potential method within the generalized gradient approximation. Both pressure- and temperature-dependent thermodynamic properties including the bulk modulus, thermal expansion, thermal expansion coefficient, and the heat capacity at constant volume and constant pressure were calculated using three different approaches based on the quasi-harmonic Debye model: the Slater, Dugdale-MacDonald (DM), and Vaschenko-Zubarev (VZ) approaches. Also, empirical energy corrections are applied to the results of models to correct the systematic errors introduced by the functional. It is found that the VZ model provides more accurate estimates in comparison with the DM and Slater models, especially after an empirical energy correction. The results obtained from the VZ analysis on the corrected static energy show that this method can be used to determine the thermodynamic properties of compounds with reasonable accuracy.

  17. New International Skeleton Tables for the Thermodynamic Properties of Ordinary Water Substance

    NASA Astrophysics Data System (ADS)

    Sato, H.; Uematsu, M.; Watanabe, K.; Saul, A.; Wagner, W.

    1988-10-01

    The current knowledge of thermodynamic properties of ordinary water substance is summarized in a condensed form of a set of skeleton steam tables, where the most probable values with the reliabilities on specific volume and enthalpy are provided in the range of temperatures from 273 to 1073 K and pressures from 101.325 kPa to 1 GPa and at the saturation state from the triple point to the critical point. These tables have been accepted as the IAPS Skeleton Tables 1985 for the Thermodynamic Properties of Ordinary Water Substance(IST-85) by the International Association for the Properties of Steam(IAPS). The former International Skeleton Steam Tables, October 1963(IST-63), have been withdrawn by IAPS. About 17 000 experimental thermodynamic data were assessed and classified previously by Working Group 1 of IAPS. About 10 000 experimental data were collected and evaluated in detail and especially about 7000 specific-volume data among them were critically analyzed with respect to their errors using the statistical method originally developed at Keio University by the first three authors. As a result, specific-volume and enthalpy values with associated reliabilities were determined at 1455 grid points of 24 isotherms and 61 isobars in the single-fluid phase state and at 54 temperatures along the saturation curve. The background, analytical procedure, and reliability of IST-85 as well as the assessment of the existing experimental data and equations of state are also discussed in this paper.

  18. Role of electronic excitation on thermodynamic and transport properties of argon and argon-hydrogen plasmas

    SciTech Connect

    Singh, Kuldip; Singh, Gurpreet; Sharma, Rohit

    2010-07-15

    Thermodynamic and electron transport properties of the argon and argon-hydrogen plasmas have been calculated under the local thermodynamic equilibrium conditions in temperature range of 10 000-40 000 K over the wide range of pressures. Electronic excitation affects strongly these properties especially at high pressures. The inclusion of electronically excited states (EES) in relevant partition function influences the internal contribution to frozen and total specific heat for argon and argon-hydrogen plasma and it has been observed that although the total specific heat of argon plasma is less than that of hydrogen plasma, yet its internal contribution is more. Compensation between different contributions to total specific heat (by including and neglecting EES) occurring in hydrogen plasmas at low pressures has not been observed in argon and argon-hydrogen plasmas. As electron transport properties strongly depend upon the degree of ionization, therefore larger relative errors are found for these properties with and without EES, and in contrast to hydrogen plasma there exist a dominance of electron-atom cross section at low temperatures and EES dominance at intermediate temperatures.

  19. Temperature Dependence of Thermodynamic Properties of Thallium Chloride and Thallium Bromide

    NASA Astrophysics Data System (ADS)

    Kavanoz, H. B.

    2015-02-01

    Thermodynamic properties as lattice parameters, thermal expansion, heat capacities Cp and Cv, bulk modulus, and Gruneisen parameter of ionic halides TlCl and TlBr in solid and liquid phases were studied using classical molecular dynamics simulation (MD) with interionic Vashistha-Rahman (VR) model potential. In addition to the static and transport properties which have been previously reported by the author [13], this study further confirms that temperature dependence of the calculated thermophysical properties of TlCl and TlBr are in agreement with the available experimental data at both solid and liquid phases in terms of providing an alternative rigid ion potential. The results give a fairly good description of TlCl and TlBr in the temperature range 10-1000 K.

  20. Computer programs for thermodynamic and transport properties of hydrogen (tabcode-II)

    NASA Technical Reports Server (NTRS)

    Roder, H. M.; Mccarty, R. D.; Hall, W. J.

    1972-01-01

    The thermodynamic and transport properties of para and equilibrium hydrogen have been programmed into a series of computer routines. Input variables are the pair's pressure-temperature and pressure-enthalpy. The programs cover the range from 1 to 5000 psia with temperatures from the triple point to 6000 R or enthalpies from minus 130 BTU/lb to 25,000 BTU/lb. Output variables are enthalpy or temperature, density, entropy, thermal conductivity, viscosity, at constant volume, the heat capacity ratio, and a heat transfer parameter. Property values on the liquid and vapor boundaries are conveniently obtained through two small routines. The programs achieve high speed by using linear interpolation in a grid of precomputed points which define the surface of the property returned.

  1. Improved relationships for the thermodynamic properties of carbon phases at detonation conditions

    NASA Astrophysics Data System (ADS)

    Stiel, L. I.; Baker, E. L.; Murphy, D. J.

    2014-05-01

    Accurate volumetric and heat capacity relationships have been developed for graphite and diamond carbon forms for use with the Jaguar thermochemical equilibrium program for the calculation of the detonation properties of explosives. Available experimental thermodynamic properties and Hugoniot values have been analyzed to establish the equations of state for the carbon phases. The diamond-graphite transition curve results from the equality of the chemical potentials of the phases. The resulting relationships are utilized to examine the actual phase behaviour of carbon under shock conditions. The existence of metastable carbon states is established by analyses of Hugoniot data for hydrocarbons and explosives at elevated temperatures and pressures. The accuracy of the resulting relationships is demonstrated by comparisons for several properties, including the Hugoniot behaviour of oxygen-deficient explosives at overdriven conditions.

  2. Unified low-parametrical equation of state for engineering calculations of thermodynamic properties of substances

    NASA Astrophysics Data System (ADS)

    Kaplun, Alexander; Meshalkin, Arkadiy

    2014-08-01

    The new simple semi empirical equation of state for description of P-?-T data of "normal" substances was specified. New equation of state has 10 individual adjustable coefficients and it describes thermal properties of gas, liquid and fluid in the main with the accuracy within the error of experimental data, except of critical region. The caloric properties and the speed of sound of argon, nitrogen and carbon dioxide were calculated with the help of known thermodynamic equations and in general divergences between calculated and tabular caloric data do not exceed the experimental error. New equation can be used for engineering calculations at the deficit of experimental data, especially on the caloric properties of substances.

  3. Computer codes for the evaluation of thermodynamic and transport properties for equilibrium air to 30000 K

    NASA Technical Reports Server (NTRS)

    Thompson, Richard A.; Lee, Kam-Pui; Gupta, Roop N.

    1991-01-01

    The computer codes developed here provide self-consistent thermodynamic and transport properties for equilibrium air for temperatures from 500 to 30000 K over a temperature range of 10 (exp -4) to 10 (exp -2) atm. These properties are computed through the use of temperature dependent curve fits for discrete values of pressure. Interpolation is employed for intermediate values of pressure. The curve fits are based on mixture values calculated from an 11-species air model. Individual species properties used in the mixture relations are obtained from a recent study by the present authors. A review and discussion of the sources and accuracy of the curve fitted data used herein are given in NASA RP 1260.

  4. Free energy of formation of Mo2C and the thermodynamic properties of carbon in solid molybdenum

    NASA Technical Reports Server (NTRS)

    Seigle, L. L.; Chang, C. L.; Sharma, T. P.

    1979-01-01

    As part of a study of the thermodynamical properties of interstitial elements in refractory metals, the free energy of formation of Mo2C is determined, and the thermodynamical properties of C in solution in solid Mo evaluated. The activity of C in the two-phase region Mo + Mo2C is obtained from the C content of iron rods equilibrated with metal + carbide powder mixtures. The free energy of formation of alpha-Mo2C is determined from the activity data. The thermodynamic properties of C in the terminal solid solution are calculated from available data on the solid solubility of C in Mo. Lattice distortion due to misfit of the C atoms in the interstitial sites appears to play a significant role in determining the thermodynamic properties of C in solid Mo.

  5. Thermodynamic properties of LnBa2Cu3O6 + z (Ln = Gd, Dy, Ho, Yb, and Y) compounds

    NASA Astrophysics Data System (ADS)

    Kovba, M. L.; Voskov, A. L.

    2015-05-01

    Thermodynamic properties of superconductors of LnBa2Cu3O6 + z (Ln = Gd, Dy, Ho, Yb, and Y) are determined by means of EMF using fluoro-ion electrolyte in the temperature range of 900-1250 K. Comparative analyses of the experimental data and thermodynamic models is performed for YBa2Cu3O6 + z compound.

  6. Thermodynamic behaviour and structural properties of an aqueous sodium chloride solution upon supercooling

    E-print Network

    D. Corradini; P. Gallo; M. Rovere

    2008-05-16

    We present the results of a molecular dynamics simulation study of thermodynamic and structural properties upon supercooling of a low concentration sodium chloride solution in TIP4P water and the comparison with the corresponding bulk quantities. We study the isotherms and the isochores for both the aqueous solution and bulk water. The comparison of the phase diagrams shows that thermodynamic properties of the solution are not merely shifted with respect to the bulk. Moreover, from the analysis of the thermodynamic curves, both the spinodal line and the temperatures of maximum density curve can be calculated. The spinodal line appears not to be influenced by the presence of ions at the chosen concentration, while the temperatures of maximum density curve displays both a mild shift in temperature and a shape modification with respect to bulk. Signatures of the presence of a liquid-liquid critical point are found in the aqueous solution. By analysing the water-ion radial distribution functions of the aqueous solution we observe that upon changing density, structural modifications appear close to the spinodal. For low temperatures additional modifications appear also for densities close to that corresponding to a low density configurational energy minimum.

  7. Determination and modeling of the thermodynamic properties of liquid calcium-antimony alloys

    SciTech Connect

    Poizeau, S; Kim, H; Newhouse, JM; Spatocco, BL; Sadoway, DR

    2012-08-01

    The thermodynamic properties of Ca-Sb alloys were determined by emf measurements in a cell configured as Ca(s)vertical bar CaF2 vertical bar Ca-Sb over the temperature range 550-830 degrees C. Activity coefficients of Ca and Sb, enthalpy, Gibbs free energy, and entropy of mixing of Ca-Sb alloys were calculated for xc(a) < 0.55. To explain the connection between short-range order of liquid Ca-Sb alloys and the strong deviation from ideality in the thermodynamic properties, two thermodynamic models were invoked and reconciled: the regular associated solution model, assuming the presence of a CaSb2 associate, and the molecular interaction volume model (MIVM). For the first time, the MIVM was used successfully to model the activity coefficients of a system with high-melting intermetallics, reducing the number of fitting parameters necessary from 5 (regular associated model) to 2 (MIVM). From the interaction parameters optimized by fitting at 800 degrees C, the with an average error of less than value. (C) 2012 Elsevier Ltd. All rights reserved,

  8. First-principles study of structural, elastic, and thermodynamic properties of ZrHf alloy

    NASA Astrophysics Data System (ADS)

    Wei, Zhao; Zhai, Dong; Shao, Xiao-Hong; Lu, Yong; Zhang, Ping

    2015-04-01

    Structural parameters, elastic constants, and thermodynamic properties of ordered and disordered solid solutions of ZrHf alloys are investigated through first-principles calculations based on density-functional theory (DFT). The special quasi-random structure (SQS) method is used to model the disordered phase as a single unit cell, and two lamella structures are generated to model the ordered alloys. Small strains are applied to the unit cells to measure the elastic behavior and mechanical stability of ZrHf alloys and to obtain the independent elastic constants by the stress-strain relationship. Phonon dispersions and phonon density of states are presented to verify the thermodynamic stability of the considered phases. Our results show that both the ordered and disordered phases of ZrHf alloys are structurally stable. Based on the obtained phonon frequencies, thermodynamic properties, including Gibbs free energy, entropy, and heat capacity, are predicted within the quasi-harmonic approximation. It is verified that there are no obvious differences in energy between ordered and disordered phases over a wide temperature range. Project supported by the National Natural Science Foundation of China (Grant No. 51102009) and the Long-Term Subsidy Mechanism from the Ministry of Finance and the Ministry of Education of China.

  9. Optimization of the thermodynamic properties and phase diagrams of P2O5-containing systems

    NASA Astrophysics Data System (ADS)

    Hudon, Pierre; Jung, In-Ho

    2014-05-01

    P2O5 is an important oxide component in the late stage products of numerous igneous rocks such as granites and pegmatites. Typically, P2O5 combines with CaO and crystallizes in the form of apatite, while in volatile-free conditions, Ca-whitlockite is formed. In spite of their interest, the thermodynamic properties and phase diagrams of P2O5-containg systems are not well known yet. In the case of the pure P2O5 for example, no experimental thermodynamic data are available for the liquid and the O and O' solid phases. As a result, we re-evaluated all the thermodynamic and phase diagram data of the P2O5 unary system [1]. Optimization of the thermodynamic properties and phase diagrams of the binary P2O5 systems was then performed including the Li2O-, Na2O-, MgO-, CaO-, BaO-, MnO-, FeO-, Fe2O3-, ZnO-, Al2O3-, and SiO2-P2O5 [2] systems. All available thermodynamic and phase equilibrium data were simultaneously reproduced in order to obtain a set of model equations for the Gibbs energies of all phases as functions of temperature and composition. In particular, the Gibbs energy of the liquid solution was described using the Modified Quasichemical Model [3-5] implemented in the FactSage software [6]. Thermodynamic modeling of the Li2O-Na2O-K2O-MgO-CaO-FeO-Fe2O3-Al2O3-SiO2 system, which include many granite-forming minerals such as nepheline, leucite, pyroxene, melilite, feldspar and spinel is currently in progress. [1] Jung, I.-H., Hudon, P. (2012) Thermodynamic assessment of P2O5. J. Am. Ceram. Soc., 95 (11), 3665-3672. [2] Rahman, M., Hudon, P. and Jung, I.-H. (2013) A coupled experimental study and thermodynamic modeling of the SiO2-P2O5 system. Metall. Mater. Trans. B, 44 (4), 837-852. [3] Pelton, A.D. and Blander, M. (1984) Computer-assisted analysis of the thermodynamic properties and phase diagrams of slags. Proc. AIME Symp. Metall. Slags Fluxes, TMS-AIME, 281-294. [4] Pelton, A.D. and Blander, M. (1986) Thermodynamic analysis of ordered liquid solutions by a modified quasichemical approach application to silicate slags. Metall. Trans. B, 17, 805-815. [5] A.D. Pelton, S.A. Decterov, G. Eriksson, C. Robelin and Y. Dessureault (2000) The modified quasichemical model - I Binary solutions. Metall. Mater. Trans. B, 31, 651-660. [6] C.W. Bale, P. Chartrand, S.A. Decterov, G. Eriksson, K. Hack, R. Ben Mahfoud, J. Melançon, A.D. Pelton and S. Petersen. (2002) FactSage Thermochemical Software and Databases. Calphad, 26, 189-228.

  10. Thermodynamic properties for applications in chemical industry via classical force fields.

    PubMed

    Guevara-Carrion, Gabriela; Hasse, Hans; Vrabec, Jadran

    2012-01-01

    Thermodynamic properties of fluids are of key importance for the chemical industry. Presently, the fluid property models used in process design and optimization are mostly equations of state or G (E) models, which are parameterized using experimental data. Molecular modeling and simulation based on classical force fields is a promising alternative route, which in many cases reasonably complements the well established methods. This chapter gives an introduction to the state-of-the-art in this field regarding molecular models, simulation methods, and tools. Attention is given to the way modeling and simulation on the scale of molecular force fields interact with other scales, which is mainly by parameter inheritance. Parameters for molecular force fields are determined both bottom-up from quantum chemistry and top-down from experimental data. Commonly used functional forms for describing the intra- and intermolecular interactions are presented. Several approaches for ab initio to empirical force field parameterization are discussed. Some transferable force field families, which are frequently used in chemical engineering applications, are described. Furthermore, some examples of force fields that were parameterized for specific molecules are given. Molecular dynamics and Monte Carlo methods for the calculation of transport properties and vapor-liquid equilibria are introduced. Two case studies are presented. First, using liquid ammonia as an example, the capabilities of semi-empirical force fields, parameterized on the basis of quantum chemical information and experimental data, are discussed with respect to thermodynamic properties that are relevant for the chemical industry. Second, the ability of molecular simulation methods to describe accurately vapor-liquid equilibrium properties of binary mixtures containing CO(2) is shown. PMID:21678137

  11. Intermolecular potentials and the accurate prediction of the thermodynamic properties of water

    SciTech Connect

    Shvab, I.; Sadus, Richard J.

    2013-11-21

    The ability of intermolecular potentials to correctly predict the thermodynamic properties of liquid water at a density of 0.998 g/cm{sup 3} for a wide range of temperatures (298–650 K) and pressures (0.1–700 MPa) is investigated. Molecular dynamics simulations are reported for the pressure, thermal pressure coefficient, thermal expansion coefficient, isothermal and adiabatic compressibilities, isobaric and isochoric heat capacities, and Joule-Thomson coefficient of liquid water using the non-polarizable SPC/E and TIP4P/2005 potentials. The results are compared with both experiment data and results obtained from the ab initio-based Matsuoka-Clementi-Yoshimine non-additive (MCYna) [J. Li, Z. Zhou, and R. J. Sadus, J. Chem. Phys. 127, 154509 (2007)] potential, which includes polarization contributions. The data clearly indicate that both the SPC/E and TIP4P/2005 potentials are only in qualitative agreement with experiment, whereas the polarizable MCYna potential predicts some properties within experimental uncertainty. This highlights the importance of polarizability for the accurate prediction of the thermodynamic properties of water, particularly at temperatures beyond 298 K.

  12. Average thermodynamic and spectral properties of plasma in and around dipolarizing flux bundles

    NASA Astrophysics Data System (ADS)

    Runov, A.; Angelopoulos, V.; Gabrielse, C.; Liu, J.; Turner, D. L.; Zhou, X.-Z.

    2015-06-01

    Recent observations have suggested that spatially localized flows of high-temperature, low-density plasma carrying a dipolarized magnetic field (dipolarizing flux bundles, DFBs) play a key role in hot plasma transport toward the inner magnetosphere. What controls plasma heating in DFBs and how do thermodynamic parameters (such as density, temperature, pressure, and specific entropy) and spectral properties of the DFB population depend on ambient plasma sheet properties and geocentric distance R remains unknown. By statistical analysis of 271 DFB events detected by the Time History of Events and Macroscale Interactions during Substorms mission during the 2008-2009 tail seasons, we find that on average, plasma inside DFBs is a factor of 0.6 less dense and a factor of 1.5 to 2 hotter than ambient tail plasma. The radial profiles of average thermodynamic parameters inside and outside DFBs are similar; when fitted by the ?-function, their energy spectra have similar ?-exponents, but a factor of 2 larger peak energies inside DFBs. Our analysis suggests that average DFB plasma properties are closely linked to those of the ambient plasma sheet population. Estimations show that on average, adiabatic heating of the ambient plasma in the increased magnetic field is the major factor in DFB plasma heating.

  13. Investigation of thermodynamic properties of ambient and laboratory-generated multi- component organic aerosols

    NASA Astrophysics Data System (ADS)

    Khlystov, A.; Lin, M.; Saleh, R.

    2008-12-01

    Ambient aerosol, a significant portion of which is composed of a complex mixture of semi-volatile organic compounds, has substantial impact on human welfare via adverse health effects and global climate change. Prediction of ambient semi-volatile organic aerosol remains highly problematic and air quality models often do not agree with observations. One of the pieces of knowledge needed for better predictions of ambient semi- volatile organic aerosol is understanding of the partitioning of semi-volatile compounds between the gas and the aerosol phases. In this study the equilibrium thermodynamic properties of a number of multi-component aerosols were investigated under controlled laboratory conditions, as well as in the field. In the laboratory experiments, model mixtures of organic compounds as well as modified ambient aerosols were tested. The ambient aerosols were modified in a controlled way by adding known amounts of different organic substances of known thermodynamic properties. The equilibrium gas / aerosol partitioning in a temperature range relevant to ambient conditions was investigated using the Integrated Volume Method (IVM). The field measurements of ambient aerosol equilibrium properties were carried out during June 2007 - January 2008 at the FACTS research facility in Duke Forest (Chapel Hill, NC). The results can be used to derive equilibrium vapor pressures and activity coefficients of test compounds and to verify and improve the parameterizations used in group contribution models, such as UNFAC.

  14. Thermodynamic properties of a geothermal working fluid; 90% isobutane-10% isopentane: Final report

    SciTech Connect

    Gallagher, J.S.; Linsky, D.; Morrison, G.; Levelt Sengers, J.M.H.

    1987-04-01

    We present tables of thermodynamic properties, and dew and bubble properties, of a mixture of 90 mol % isobutane and 10 mol % isopentane, a working fluid in a binary geothermal power cycle. The tables are generated by a formulation of the Helmholtz free energy, in which the mixture properties are mapped onto the known properties of pure isobutane by means of the principle of generalized corresponding states. The data base for the Helmholtz free energy formulation is new. We report data obtained in three different apparatus: critical-line and isopentane vapor pressure data obtained in a visual cell; vapor-liquid equilibria data obtained in a mercury-operated variable-volume cell; and pressure-volume-temperature data for the 90 mol %-10 mol % mixture obtained in a semi-automated Burnett-isochoric apparatus. The principles of the methods, and estimates of the reliability, are discussed and all experimental data are compared with the surface. The results are tables of specific volume, enthalpy, entropy, specific heat and density and temperature derivatives of the pressure at 10 K temperature increments from 240 to 600 K along isobars from 0.01 to 20 MPa. Separate tables are prepared from the dew and bubble properties of the 90-10 mixture. Estimates of the effects of isomeric impurity of isobutane are given in graphical form.

  15. Origin and thermodynamic properties of the instability of synthetic azo colorants in gum arabic solutions.

    PubMed

    Fang, Yapeng; Al-Assaf, Saphwan; Sakata, Makoto; Phillips, Glyn O; Schultz, Matthias; Monnier, Vivianne

    2007-10-31

    The instability of some industrially important synthetic azo colorants, including sunset yellow, azorubine, and allura red, toward gum arabic in aqueous solution has been a long-standing problem for the beverage and confectionery industries. Precipitation of these colorants causes the deterioration of product appearance and properties. This work examines the origin and nature of the problem by analysis of the precipitate and thermodynamic studies of gum arabic-colorant interactions using isothermal titration calorimetry (ITC). The presence of divalent alkaline earth metals in gum arabic samples, that is, calcium and magnesium, is shown to be responsible for the precipitation of the azo colorants. There is no direct interaction between gum arabic and the colorant molecules, and the precipitate is formed likely due to the mediation/bridging by the divalent cations. The thermodynamic knowledge gained from the ITC studies, for example, binding affinity, stoichiometry, and enthalpy, enables interpretation of many industrial observations. PMID:17910512

  16. Effects of heavy ion irradiation on the thermodynamic and transport properties of YBCO

    NASA Astrophysics Data System (ADS)

    Luo, Xu; Leroux, Maxime; Mishra, Vivek; Ling, Xinsheng; Welp, Ulrich; Kwok, Wai-Kwong

    2015-03-01

    The effects of Au heavy ion irradiation (HII) on the transport and thermodynamic properties of untwined YBCO crystals irradiated to dose matching fields of B? = 6 Tesla and 1 Tesla along the crystallographic c-axis were studied by angle resolved magnetoresistivtiy and high resolution AC specific heat measurements. Results from transport measurements confirm an enhancement in the ab-plane critical current for magnetic fields aligned along the columnar defects induced by HII. Surprisingly, specific heat measurements reveal a reduction in the thermodynamic upper critical field anisotropy of YBCO by about one half in the B? = 6T crystal. Moreover, for the B? = 1T crystal, we found the formation of an anomalous peak in the critical temperature near the direction of HII which may be associated with the Bose-glass transition. Work supported by Department of Energy, Office of Science, Office of Basic Energy Sciences under Contract No. DE-AC02-06CH11357.

  17. Dielectric properties of human diabetic blood: Thermodynamic characterization and new prospective for alternative diagnostic techniques

    NASA Astrophysics Data System (ADS)

    Farsaci, F.; Ficarra, S.; Russo, A.; Galtieri, A.; Tellone, E.

    2015-07-01

    In this paper, we will show the possibility of studying physical properties and irreversible phenomena that occur in blood by applying the dielectric Kluitenberg's nonequilibrium thermodynamic theory. Namely, we shall use some recent extensions of this theory that allow to infer its main characteristic parameters from experimental measures. Applying these results to the study of normal and diabetic blood we show, by comparing them, that it is possible to determine the difference, in some details, of the amount of particular phenomena occurring inside them and give a biological meaning to these phenomena. Moreover, observing a correspondence between a particular value of the frequency for which state coefficients are equal and glucose levels we introduce an alternative diagnostic method to measure the values of the glucose in the blood by determining only this frequency value. The thermodynamic description will be completed by determining the trend of the entropy production.

  18. Modeling of Thermodynamic Properties and Phase Equilibria for the Al-Sm Binary System

    SciTech Connect

    Zhou, S.H.; Napolitano, R.E.

    2008-01-25

    The thermodynamic properties and associated phase equilibria for the Al-Sm binary system are examined, and experimental results regarding the stability of the Al{sub 3}Sm, Al{sub 11}Sm{sub 3}, and Al{sub 4}Sm intermetallics are incorporated. In the analysis presented, the liquid phase is described using a three-species association model, the intermediate phases are treated as stoichiometric compounds, and the terminal phases are treated as solid solutions with a single sublattice model. In addition to the stable phases, thermodynamic descriptions of the metastable Al{sub 11}Sm{sub 3}-{alpha} and Al{sub 4}Sm-{gamma} phases are employed, and both stable and metastable phase equilibria are presented over the full composition range, providing a general model, which is consistent with available experimental data. Metastable liquidus curves are examined with respect to the observed crystallization behavior of amorphous Al-Sm alloys.

  19. Emergence of equilibrium thermodynamic properties in quantum pure states. I. Theory.

    PubMed

    Fresch, Barbara; Moro, Giorgio J

    2010-07-21

    Investigation on foundational aspects of quantum statistical mechanics recently entered a renaissance period due to novel intuitions from quantum information theory and to increasing attention on the dynamical aspects of single quantum systems. In the present contribution a simple but effective theoretical framework is introduced to clarify the connections between a purely mechanical description and the thermodynamic characterization of the equilibrium state of an isolated quantum system. A salient feature of our approach is the very transparent distinction between the statistical aspects and the dynamical aspects in the description of isolated quantum systems. Like in the classical statistical mechanics, the equilibrium distribution of any property is identified on the basis of the time evolution of the considered system. As a consequence equilibrium properties of quantum system appear to depend on the details of the initial state due to the abundance of constants of the motion in the Schrodinger dynamics. On the other hand the study of the probability distributions of some functions, such as the entropy or the equilibrium state of a subsystem, in statistical ensembles of pure states reveals the crucial role of typicality as the bridge between macroscopic thermodynamics and microscopic quantum dynamics. We shall consider two particular ensembles: the random pure state ensemble and the fixed expectation energy ensemble. The relation between the introduced ensembles, the properties of a given isolated system, and the standard quantum statistical description are discussed throughout the presentation. Finally we point out the conditions which should be satisfied by an ensemble in order to get meaningful thermodynamical characterization of an isolated quantum system. PMID:20649339

  20. Natural Bond Orbital (NBO) Population Analysis, First Order Hyperpolarizabilities and Thermodynamic Properties of Cyclohexanone.

    PubMed

    Gangadharan, Rubarani P; Krishnan, S Sampath

    2015-06-01

    The molecular structure of cyclohexanone was calculated by the B3LYP density functional model with 6-31G(d, p) and 6-311++G(d,p) basis set by Gaussian program. The results from natural bond orbital (NBO) analysis have been analyzed in terms of the hybridization of atoms and the electronic structure of the title molecule. The electron density based local reactivity descriptors such as Fukui functions were calculated. The dipole moment (?) and polarizability (a), anisotropy polarizability (??) and first order hyperpolarizability (?(tot)) of the molecule have been reported. Thermodynamic properties of the title compound were calculated at different temperatures. PMID:26601356

  1. Thermodynamic properties of semiconductor compounds studied based on Debye-Waller factors

    NASA Astrophysics Data System (ADS)

    Van Hung, Nguyen; Toan, Nguyen Cong; Ba Duc, Nguyen; Vuong, Dinh Quoc

    2015-08-01

    Thermodynamic properties of semiconductor compounds have been studied based on Debye-Waller factors (DWFs) described by the mean square displacement (MSD) which has close relation with the mean square relative displacement (MSRD). Their analytical expressions have been derived based on the statistical moment method (SMM) and the empirical many-body Stillinger-Weber potentials. Numerical results for the MSDs of GaAs, GaP, InP, InSb, which have zinc-blende structure, are found to be in reasonable agreement with experiment and other theories. This paper shows that an elements value for MSD is dependent on the binary semiconductor compound within which it resides.

  2. Examination of two methods of describing the thermodynamic properties of oxygen near the critical point

    NASA Technical Reports Server (NTRS)

    Rees, T. H.; Suttles, J. T.

    1972-01-01

    A computer study was conducted to compare the numerical behavior of two approaches to describing the thermodynamic properties of oxygen near the critical point. Data on the relative differences between values of specific heats at constant pressure (sub p) density, and isotherm and isochor derivatives of the equation of state are presented for selected supercritical pressures at temperatures in the range 100 to 300 K. The results of a more detailed study of the sub p representations afforded by the two methods are also presented.

  3. Calculating the thermodynamic properties of aqueous solutions of alkali metal carboxylates

    NASA Astrophysics Data System (ADS)

    Rudakov, A. M.; Sergievskii, V. V.; Zhukova, T. V.

    2014-06-01

    A modified Robinson-Stokes equation with terms that consider the formation of ionic hydrates and associates is used to describe thermodynamic properties of aqueous solutions of electrolytes. The model is used to describe data on the osmotic coefficients of aqueous solutions of alkali metal carboxylates, and to calculate the mean ionic activity coefficients of salts and excess Gibbs energies. The key contributions from ionic hydration and association to the nonideality of solutions is determined by analyzing the contributions of various factors. Relations that connect the hydration numbers of electrolytes with the parameters of the Pitzer-Mayorga equation and a modified Hückel equation are developed.

  4. Atomic structure, mechanical quality, and thermodynamic property of TiHx phases

    NASA Astrophysics Data System (ADS)

    Liang, C. P.; Gong, H. R.

    2013-07-01

    Titanium hydrides TiHx (x = 1, 1.25, 1.5, 1.75, and 2) with the cubic fluorite-type (face-centered cubic, ? phase) and face-centered-tetragonal (? phase, c/a < 1; ? phase, c/a > 1) structures were systematically investigated and compared through first-principles calculation. The H location of TiHx was carefully determined by comparing the calculated properties with experimental results. Moreover, the mechanical properties of ? and ? phases were calculated and found to play an important role in the brittle/ductile behavior of TiHx phases. In addition, the thermodynamic quantities were also derived for providing a deeper understanding of TiHx phases. The calculated results were widely compared with the available experimental results in the literature, and could clarify the three controversies regarding atomic configuration, stability, and hydrogen embrittlement of TiHx phases in the literature.

  5. Structural, electronic, thermodynamical and charge transfer properties of Chloramphenicol Palmitate using vibrational spectroscopy and DFT calculations

    NASA Astrophysics Data System (ADS)

    Mishra, Rashmi; Srivastava, Anubha; Sharma, Anamika; Tandon, Poonam; Baraldi, Cecilia; Gamberini, Maria Christina

    2013-01-01

    The global problem of advancing bacterial resistance to newer drugs has led to renewed interest in the use of Chloramphenicol Palmitate (C27H42Cl2N2O6) [Palmitic acid alpha ester with D-threo-(-),2-dichloro-N-(beta-hydroxy-alpha-(hydroxymethyl)-p-nitrophenethyl)acetamide also known as Detereopal]. The characterization of the three polymorphic forms of Chloramphenicol Palmitate (CPP) was done spectroscopically by employing FT-IR and FT-Raman techniques. The equilibrium geometry, various bonding features, and harmonic wavenumbers have been investigated for most stable form A with the help of DFT calculations and a good correlation was found between experimental data and theoretical values. Electronic properties have been analyzed employing TD-DFT for both gaseous and solvent phase. The theoretical calculation of thermodynamical properties along with NBO analysis has also been performed to have a deep insight into the molecule for further applications.

  6. An effective pair potential for thermodynamics and structural properties of liquid mercury

    NASA Astrophysics Data System (ADS)

    Bomont, Jean-Marc; Bretonnet, Jean-Louis

    2006-02-01

    The properties of liquid mercury are investigated by using an empirical effective pair potential. Its parameters are determined with the aid of Monte Carlo simulation along the liquid branch of the liquid-vapor coexistence curve. The complexity of the electronic structure of dense metal mercury supposes a state dependence of the interatomic interactions, while no more state dependence is found in the metal-nonmetal transition region. It is shown that the use of this effective potential leads to an accurate description of the structural and thermodynamic properties of the expanded liquid mercury. Then, the melting and freezing phenomena are investigated with that potential. Sharp melting and freezing temperatures are observed at 234 and 169K, respectively. This large hysteresis loop between freezing and melting is consistent with the experiments for the bulk mercury.

  7. An effective pair potential for thermodynamics and structural properties of liquid mercury.

    PubMed

    Bomont, Jean-Marc; Bretonnet, Jean-Louis

    2006-02-01

    The properties of liquid mercury are investigated by using an empirical effective pair potential. Its parameters are determined with the aid of Monte Carlo simulation along the liquid branch of the liquid-vapor coexistence curve. The complexity of the electronic structure of dense metal mercury supposes a state dependence of the interatomic interactions, while no more state dependence is found in the metal-nonmetal transition region. It is shown that the use of this effective potential leads to an accurate description of the structural and thermodynamic properties of the expanded liquid mercury. Then, the melting and freezing phenomena are investigated with that potential. Sharp melting and freezing temperatures are observed at 234 and 169 K, respectively. This large hysteresis loop between freezing and melting is consistent with the experiments for the bulk mercury. PMID:16468891

  8. Improved Relationships for the Thermodynamic Properties of Carbon Phases at Detonation Conditions

    NASA Astrophysics Data System (ADS)

    Stiel, Leonard; Baker, Ernest; Murphy, Daniel

    2013-06-01

    In order to improve the procedures utilized in the Jaguar thermochemical program for carbon, volumetric and heat capacity relationships have been developed for graphite, diamond, and liquid carbon forms. Available experimental thermodynamic property and Hugoniot data have been analyzed to establish optimum equations of state for the carbon phases. The appropriate carbon form or multiple forms at equilibrium results from the minimization of the Gibbs free energy of the system. The resulting relationships are utilized to examine the phase behavior of carbon at elevated temperatures and pressures. The behavior of metastable carbon states is optimized by analyses of Hugoniot data for hydrocarbons, and C-J and cylinder velocities for a database of CHNO explosives. The accuracy of the resulting relationships is demonstrated by comparisons for several properties, including the Hugoniot behavior of oxygen-deficient explosives at overdriven conditions.

  9. Thermodynamic Properties of CaSiO3 Perovskite at High Pressure and High Temperature

    NASA Astrophysics Data System (ADS)

    Liu, Zi-Jiang; Tan, Xiao-Ming; Guo, Yuan; Zheng, Xiao-Ping; Wu, Wen-Zhao

    2009-06-01

    The thermodynamic properties of tetragonal CaSiO3 perovskite are predicted at high pressures and temperatures using the Debye model for the first time. This model combines the ab initio calculations within local density approximation using pseudopotentials and a plane wave basis in the framework of density functional theory, and it takes into account the phononic effects within the quasi-harmonic approximation. It is found that the calculated equation of state is in excellent agreement with the observed values at ambient condition. Based on the first-principles study and the Debye model, the thermal properties including the Debye temperature, the heat capacity, the thermal expansion and the entropy are obtained in the whole pressure range from 0 to 150 GPa and temperature range from 0 to 2000 K.

  10. Thermodynamic properties of gaseous fluorocarbons and isentropic equilibrium expansions of two binary mixtures of fluorocarbons and argon

    NASA Technical Reports Server (NTRS)

    Talcott, N. A., Jr.

    1977-01-01

    Equations and computer code are given for the thermodynamic properties of gaseous fluorocarbons in chemical equilibrium. In addition, isentropic equilibrium expansions of two binary mixtures of fluorocarbons and argon are included. The computer code calculates the equilibrium thermodynamic properties and, in some cases, the transport properties for the following fluorocarbons: CCl2F, CCl2F2, CBrF3, CF4, CHCl2F, CHF3, CCL2F-CCl2F, CCLF2-CClF2, CF3-CF3, and C4F8. Equilibrium thermodynamic properties are tabulated for six of the fluorocarbons(CCl3F, CCL2F2, CBrF3, CF4, CF3-CF3, and C4F8) and pressure-enthalpy diagrams are presented for CBrF3.

  11. SteamTablesGrid: An ActiveX control for thermodynamic properties of pure water

    NASA Astrophysics Data System (ADS)

    Verma, Mahendra P.

    2011-04-01

    An ActiveX control, steam tables grid ( StmTblGrd) to speed up the calculation of the thermodynamic properties of pure water is developed. First, it creates a grid (matrix) for a specified range of temperature (e.g. 400-600 K with 40 segments) and pressure (e.g. 100,000-20,000,000 Pa with 40 segments). Using the ActiveX component SteamTables, the values of selected properties of water for each element (nodal point) of the 41×41 matrix are calculated. The created grid can be saved in a file for its reuse. A linear interpolation within an individual phase, vapor or liquid is implemented to calculate the properties at a given value of temperature and pressure. A demonstration program to illustrate the functionality of StmTblGrd is written in Visual Basic 6.0. Similarly, a methodology is presented to explain the use of StmTblGrd in MS-Excel 2007. In an Excel worksheet, the enthalpy of 1000 random datasets for temperature and pressure is calculated using StmTblGrd and SteamTables. The uncertainty in the enthalpy calculated with StmTblGrd is within ±0.03%. The calculations were performed on a personal computer that has a "Pentium(R) 4 CPU 3.2 GHz, RAM 1.0 GB" processor and Windows XP. The total execution time for the calculation with StmTblGrd was 0.3 s, while it was 60.0 s for SteamTables. Thus, the ActiveX control approach is reliable, accurate and efficient for the numerical simulation of complex systems that demand the thermodynamic properties of water at several values of temperature and pressure like steam flow in a geothermal pipeline network.

  12. Calculations and curve fits of thermodynamic and transport properties for equilibrium air to 30000 K

    NASA Technical Reports Server (NTRS)

    Gupta, Roop N.; Lee, Kam-Pui; Thompson, Richard A.; Yos, Jerrold M.

    1991-01-01

    A self-consistent set of equilibrium air values were computed for enthalpy, total specific heat at constant pressure, compressibility factor, viscosity, total thermal conductivity, and total Prandtl number from 500 to 30,000 K over a range of 10(exp -4) atm to 10(exp 2) atm. The mixture values are calculated from the transport and thermodynamic properties of the individual species provided in a recent study by the authors. The concentrations of the individual species, required in the mixture relations, are obtained from a free energy minimization calculation procedure. Present calculations are based on an 11-species air model. For pressures less than 10(exp -2) atm and temperatures of about 15,000 K and greater, the concentrations of N(++) and O(++) become important, and consequently, they are included in the calculations determining the various properties. The computed properties are curve fitted as a function of temperature at a constant value of pressure. These curve fits reproduce the computed values within 5 percent for the entire temperature range considered here at specific pressures and provide an efficient means for computing the flowfield properties of equilibrium air, provided the elemental composition remains constant at 0.24 for oxygen and 0.76 for nitrogen by mass.

  13. Thermodynamic properties of calcium-magnesium alloys determined by emf measurements

    SciTech Connect

    Newhouse, JM; Poizeau, S; Kim, H; Spatocco, BL; Sadoway, DR

    2013-02-28

    The thermodynamic properties of calcium-magnesium alloys were determined by electromotive force (emf) measurements using a Ca(in Bi)vertical bar CaF2 vertical bar Ca(in Mg) cell over the temperature range 713-1048 K. The activity and partial molar Gibbs free energy of calcium in magnesium were calculated for nine Ca-Mg alloys, calcium mole fractions varying from x(ca) = 0.01 to 0.80. Thermodynamic properties of magnesium in calcium and the molar Gibbs free energy of mixing were estimated using the Gibbs-Duhem relationship. In the all-liquid region at 1010 K, the activity of calcium in magnesium was found to range between 8.8 x 10(-4) and 0.94 versus pure calcium. The molecular interaction volume model (MIVM) was used to model the activity coefficient of Ca and Mg in Ca-Mg liquid alloys. Based on this work, Ca-Mg alloys show promise as the negative electrode of a liquid metal battery in which calcium is the itinerant species: alloying with Mg results in both a decrease in operating temperature and suppression of Ca metal solubility in the molten salt electrolyte. (C) 2012 Elsevier Ltd. All rights reserved.

  14. Elastic and thermodynamical properties of cubic (3 C) silicon carbide under high pressure and high temperature

    NASA Astrophysics Data System (ADS)

    Varshney, Dinesh; Shriya, S.; Varshney, M.; Singh, N.; Khenata, R.

    2015-08-01

    Pressure-dependent first-order phase transition, mechanical, elastic, and thermodynamical properties of cubic zinc blende to rock-salt structures in 3 C silicon carbide (SiC) are presented. An effective interatomic interaction potential for SiC is formulated. The potential for SiC incorporates long-range Coulomb, charge transfer interactions, covalency effect, Hafemeister and Flygare type short-range overlap repulsion extended up to the second-neighbour ions, van der Waals interactions and zero point energy effects. The developed potential including many body non-central forces validates the Cauchy discrepancy successfully to explain the high-pressure structural transition, and associated volume collapse. The 3 C SiC ceramics lattice infers mechanical stiffening, thermal softening, and ductile (brittle) nature from the pressure (temperature) dependent elastic constants behaviour. To our knowledge, these are the first quantitative theoretical predictions of the pressure and temperature dependence of mechanical and thermodynamical properties explicitly the mechanical stiffening, thermally softening, and brittle/ductile nature of 3 C SiC and still awaits experimental confirmations.

  15. Evaluation of the thermodynamic properties of hydrated metal oxide nanoparticles by INS techniques

    SciTech Connect

    Spencer, Elinor; Ross, Dr. Nancy; Parker, Stewart F.; Kolesnikov, Alexander I

    2013-01-01

    In this contribution we will present a detailed methodology for the elucidation of the following aspects of the thermodynamic properties of hydrated metal oxide nanoparticles from high-resolution, low-temperature inelastic neutron scattering (INS) data: (i) the isochoric heat capacity and entropy of the hydration layers both chemi- and physisorbed to the particle surface; (ii) the magnetic contribution to the heat capacity of the nanoparticles. This will include the calculation of the vibrational density of states (VDOS) from the raw INS spectra, and the subsequent extraction of the thermodynamic data from the VDOS. This technique will be described in terms of a worked example namely, cobalt oxide (Co3O4 and CoO). To complement this evaluation of the physical properties of metal oxide nanoparticle systems, we will emphasise the importance of high-resolution, high-energy INS for the determination of the structure and dynamics of the water species, namely molecular (H2O) and dissociated water (OH, hydroxyl), confined to the oxide surfaces. For this component of the chapter we will focus on INS investigations of hydrated isostructural rutile (a-TiO2) and cassiterite (SnO2) nanoparticles. We will complete this discussion of nanoparticle analysis by including an appraisal of the INS instrumentation employed in such studies with particular focus on TOSCA [ISIS, Rutherford Appleton Laboratory (RAL), U.K.] and the newly developed spectrometer SEQUOIA [SNS, Oak Ridge National Laboratory (ORNL), U.S.A].

  16. Two-dimensional materials as emulsion stabilizers: interfacial thermodynamics and molecular barrier properties.

    PubMed

    Creighton, Megan A; Ohata, Yuzo; Miyawaki, Jin; Bose, Arijit; Hurt, Robert H

    2014-04-01

    A new application for two-dimensional (2D) materials is emulsification, where they can serve as ultrathin platelike interfacial stabilizers in two-liquid systems. We present a first detailed thermodynamic analysis of atomically thin 2D materials at organic-aqueous liquid-liquid interfaces and derive expressions for the transfer free energies of emulsion stabilization that account for material geometry, van der Waals transparency or opacity, and variable hydrophobicity. High mass potency is shown to be an intrinsic property of the 2D geometry, which at the atomically thin limit places every atom in contact with both liquid phases, resulting in unit atom efficiency. The thermodynamic model successfully predicts that graphene oxide but not pristine graphene has a favorable hydrophobic-hydrophilic balance for oil-water emulsion stabilization. Multilayer tiling is predicted to occur by the passivation of droplet surface patches left uncovered by packing inefficiencies in the first monolayer, and complete multilayer coverage is confirmed by cryogenic scanning electron microscopy. The molecular barrier function of graphene interfacial films causes a significant suppression of dispersed-phase evaporation rates with potential applications in controlled release. Finally, these emulsions can be used as templates for creating solid graphene foams or graphene microsacks filled with lipophilic cargos. Emerging 2D materials are promising as dispersants or emulsifiers where high mass potency and multifunctional properties are desired. PMID:24625132

  17. Thermodynamic Properties of Carbosilane Dendrimers of the Sixth Generation with Ethylene Oxide Terminal Groups.

    PubMed

    Sologubov, Semen S; Markin, Alexey V; Smirnova, Natalia N; Novozhilova, Natalia A; Tatarinova, Elena A; Muzafarov, Aziz M

    2015-11-12

    The temperature dependences of heat capacities of carbosilane dendrimers of the sixth generation with ethyleneoxide terminal groups, denoted as G6[(OCH2CH2)1OCH3]256 and G6[(OCH2CH2)3OCH3]256, were measured in the temperature range from T = (6 to 520) K by precision adiabatic calorimetry and differential scanning calorimetry (DSC). In the above temperature range the physical transformations, such as glass transition and high-temperature relaxation transition, were detected. The standard thermodynamic characteristics of the revealed transformations were determined and analyzed. The standard thermodynamic functions, namely, heat capacity Cp°(T), enthalpy H°(T) - H°(0), entropy S°(T) - S°(0), and Gibbs energy G°(T) - H°(0) for the range from T ? 0 to 520 K, and the standard entropies of formation ?fS° of the investigated dendrimers in the devitrified state at T = 298.15 K, were calculated per corresponding moles of the notional structural units. The standard thermodynamic properties of dendrimers under study were discussed and compared with literature data for carbosilane dendrimers with different functional terminal groups. PMID:26494191

  18. Phonon densities of states and related thermodynamic properties of high temperature ceramics.

    SciTech Connect

    Loong, C.-K.

    1998-08-28

    Structural components and semiconductor devices based on silicon nitride, aluminum nitride and gallium nitride are expected to function more reliably at elevated temperatures and at higher levels of performance because of the strong atomic bonding in these materials. The degree of covalency, lattice specific heat, and thermal conductivity are important design factors for the realization of advanced applications. We have determined the phonon densities of states of these ceramics by the method of neutron scattering. The results provide a microscopic interpretation of the mechanical and thermal properties. Moreover, experimental data of the static, structures, and dynamic excitations of atoms are essential to the validation of interparticle potentials employed for molecular-dynamics simulations of high-temperature properties of multi-component ceramic systems. We present an overview of neutron-scattering investigations of the atomic organization, phonon excitations, as well as calculations of related thermodynamic properties of Si{sub 3}N{sub 4}, {beta}-sialon, AlN and GaN. The results are compared with those of the oxide analogs such as SiO{sub 2} and Al{sub 2}O{sub 3}.

  19. First-principles investigation on mechanical, electronic, and thermodynamic properties of Mg{sub 2}Sr under high pressure

    SciTech Connect

    Mao, Pingli Yu, Bo; Liu, Zheng; Wang, Feng; Ju, Yang

    2015-03-21

    The structural, mechanical, electronic, and thermodynamic properties of Mg{sub 2}Sr with C14-type structure under pressures ranging from 0 to 40?GPa have been systematically studied within the framework of density functional theory in this work. The results at zero pressure were in good agreement with the available theoretical and experimental values. The pressure dependence of structure and elastic constants, elastic anisotropy, Cauchy pressure, melting points, and hardness was successfully calculated and discussed. In addition, the electronic density of states (DOSs) under various pressures were investigated. Debye temperature and the dependences of thermodynamic properties on temperature and pressure were also discussed in the present paper.

  20. Thermodynamic and related properties of parahydrogen from the triple point to 300 K at pressures to 1000 bar

    NASA Technical Reports Server (NTRS)

    Weber, L. A.

    1975-01-01

    Compressibility measurements and thermodynamic properties data for parahydrogen were extended to higher temperatures and pressures. Results of an experimental program are presented in the form of new pressure, volume and temperature data in the temperature range 23 to 300 K at pressures up to 800 bar. Also given are tables of thermodynamic properties on isobars to 1000 bar including density, internal energy, enthalpy, entropy, specific heats at constant volume and constant pressure, velocity of sound, and surface derivatives. The accuracy of the data is discussed and comparisons are made with previous data.

  1. Tables and charts of equilibrium thermodynamic properties of ammonia for temperatures from 500 to 50,000 K.

    NASA Technical Reports Server (NTRS)

    Simmonds, A. L.; Miller, C. G., III; Nealy, J. E.

    1976-01-01

    Equilibrium thermodynamic properties for pure ammonia were generated for a range of temperature from 500 to 50,000 K and pressure from 0.01 to 40 MN/sq m and are presented in tabulated and graphical form. Properties include pressure, temperature, density, enthalpy, speed of sound, entropy, molecular-weight ratio, specific heat at constant pressure, specific heat at constant volume, isentropic exponent, and species mole fractions. These properties were calculated by the method which is based on minimization of the Gibbs free energy. The data presented herein are for an 18-species ammonia model. Heats of formation and spectroscopic constants used as input data are presented. Comparison of several thermodynamic properties calculated with the present program and a second computer code is performed for a range of pressure and for temperatures up to 30,000 K.

  2. Thermodynamic and Ultrasonic Properties of Ascorbic Acid in Aqueous Protic Ionic Liquid Solutions

    PubMed Central

    Singh, Vickramjeet; Sharma, Gyanendra; Gardas, Ramesh L.

    2015-01-01

    In this work, we report the thermodynamic and ultrasonic properties of ascorbic acid (vitamin C) in water and in presence of newly synthesized ammonium based protic ionic liquid (diethylethanolammonium propionate) as a function of concentration and temperature. Apparent molar volume and apparent molar isentropic compression, which characterize the solvation state of ascorbic acid (AA) in presence of protic ionic liquid (PIL) has been determined from precise density and speed of sound measurements at temperatures (293.15 to 328.15) K with 5 K interval. The strength of molecular interactions prevailing in ternary solutions has been discussed on the basis of infinite dilution partial molar volume and partial molar isentropic compression, corresponding volume of transfer and interaction coefficients. Result has been discussed in terms of solute-solute and solute-solvent interactions occurring between ascorbic acid and PIL in ternary solutions (AA + water + PIL). PMID:26009887

  3. Thermodynamic, transport, and flow properties of gaseous products resulting from combustion of methane-air-oxygen

    NASA Technical Reports Server (NTRS)

    Klich, G. F.

    1976-01-01

    Results of calculations to determine thermodynamic, transport, and flow properties of combustion product gases are presented. The product gases are those resulting from combustion of methane-air-oxygen and methane-oxygen mixtures. The oxygen content of products resulting from the combustion of methane-air-oxygen mixtures was similiar to that of air; however, the oxygen contained in products of methane-oxygen combustion ranged from 20 percent by volume to zero for stoichiometric combustion. Calculations were made for products of reactant mixtures with fuel percentages, by mass, of 7.5 to 20. Results are presented for specific mixtures for a range of pressures varying from 0.0001 to 1,000 atm and for temperatures ranging from 200 to 3,800 K.

  4. Calculation of thermodynamic properties of dense fluid neon using statistical-mechanical perturbation theory

    NASA Astrophysics Data System (ADS)

    Kortbeek, P. J.; Schouten, J. A.

    Thermodynamic properties of dense fluid neon were calculated between 73 and 348K and up to 1 GPa, using Ross' variational perturbation theory. Parameter values for the EXP-6 effective pair potential were determined by matching the calculated sound velocities to experimental data in the ranges 100-300K and 0·1-1GPa. Calculations with this potential and with several pure pair potentials (XC, HFD etc.) were compared with experimental pVT and sound-velocity data. The effect of the Axilrod-Teller many-body correction term on the pure pair potentials was studied. The EXP-6 potential describes the experimental data up to 1 GPa with an accuracy almost equal to the experimental error. The pressure dependence of the specific heat at constant volume is shown along several isotherms.

  5. Ab-initio elastic and thermodynamic properties of high-temperature cubic intermetallics at finite temperatures 

    E-print Network

    Williams, Michael Eric

    2009-05-15

    thermodynamics [9] to calculate the temperature dependence of several properties according to established equations such as: S = @F(T)@T ; (2.1a) H = F(T) T@F(T)@T ; (2.1b) Cp = T@S@T; (2.1c) B = V @2F @V 2 : (2.1d) Which come from local slopes and curvatures... at low temperatures [37]. If we look at the specific heat at constant pressure Cp and include the anharmonic free energy according to this method we find thatCp(T !0)/T. From quantum mechanics we know that Cp(T !0)/T4 and therefore we can say...

  6. Phase liquid-vapor equilibria and thermodynamic properties of solutions of n-propanol-aliphatic ketones

    NASA Astrophysics Data System (ADS)

    Suntsov, Yu. K.; Vlasov, M. V.; Chuikov, A. M.

    2015-06-01

    The boiling points of solutions of five binary systems are measured using the ebulliometric method in the pressure range of 4.4-101.3 kPa. Compositions of the equilibrium vapor phases of systems are calculated, based on the constructed pressure isotherms of saturated vapor. The values of excess Gibbs energy and the enthalpy and entropy of solutions are calculated from the data on the liquid-vapor equilibrium. The patterns of change in the phase equilibria and thermodynamic properties of the solutions are established, based on the composition and temperature of the systems. The liquid-vapor equilibrium of systems is described using the equations of Wilson and the NRTL (Non-Random Two-Liquid model).

  7. Tables of equation-of-state, thermodynamic properties, and shock Hugoniot for hot dense fluid deuterium

    E-print Network

    Zaghloul, Mofreh R

    2015-01-01

    We present computational results and tables of the equation-of-state, thermodynamic properties, and shock Hugoniot for hot dense fluid deuterium. The present results are generated using a recently developed chemical model that takes into account different high density effects such as Coulomb interactions among charged particles, partial degeneracy, and intensive short range hard core repulsion. Internal partition functions are evaluated in a statistical-mechanically consistent way implementing recent developments in the literature. The shock Hugoniot curve derived from the present tables is in reasonable overall agreement with the Hugoniot derived from the Nova-laser shock wave experiments on liquid deuterium, showing that deuterium has a significantly higher compressibility than predicted by the SESAME tables or by Path Integral Monte Carlo (PIMC) calculations. Computational results are presented as surface plots for the dissociated fraction, degree of ionization, pressure, and specific internal energy for d...

  8. Investigations on thermodynamic properties of the three sub-lattice spin frustrated chain

    NASA Astrophysics Data System (ADS)

    Wang, Jue; Zhou, Hong-Fei; Li, Qian-Chun; Dong, Hui-Ning

    2015-08-01

    The spin frustration related to the high-Tc superconductivity has received much attention. In this paper, based on the Jordan-Wigner transformation and Green’s function method, we study the magnetic and thermodynamic properties of the three sub-lattice spin frustrated chains. It is found that there are three branches for the spin-wave excitation spectra at zero temperature. Among them, two belong to nature excitation patterns with antiferromagnetic interaction and the third one is band gap excitation spectrum with ferromagnetic nature. The specific heat capacity of sub-lattice spin system presents complex characteristics with the change of temperature due to the intense competition between the ferromagnetic and antiferromagnetic interactions. It is also shown that the increase of the ferromagnetic action is helpful to the value of net spin.

  9. Thermodynamic properties of non-conformal soft-sphere fluids with effective hard-sphere diameters.

    PubMed

    Rodríguez-López, Tonalli; del Río, Fernando

    2012-01-28

    In this work we study a set of soft-sphere systems characterised by a well-defined variation of their softness. These systems represent an extension of the repulsive Lennard-Jones potential widely used in statistical mechanics of fluids. This type of soft spheres is of interest because they represent quite accurately the effective intermolecular repulsion in fluid substances and also because they exhibit interesting properties. The thermodynamics of the soft-sphere fluids is obtained via an effective hard-sphere diameter approach that leads to a compact and accurate equation of state. The virial coefficients of soft spheres are shown to follow quite simple relationships that are incorporated into the equation of state. The approach followed exhibits the rescaling of the density that produces a unique equation for all systems and temperatures. The scaling is carried through to the level of the structure of the fluids. PMID:22158949

  10. Thermodynamic and ultrasonic properties of ascorbic Acid in aqueous protic ionic liquid solutions.

    PubMed

    Singh, Vickramjeet; Sharma, Gyanendra; Gardas, Ramesh L

    2015-01-01

    In this work, we report the thermodynamic and ultrasonic properties of ascorbic acid (vitamin C) in water and in presence of newly synthesized ammonium based protic ionic liquid (diethylethanolammonium propionate) as a function of concentration and temperature. Apparent molar volume and apparent molar isentropic compression, which characterize the solvation state of ascorbic acid (AA) in presence of protic ionic liquid (PIL) has been determined from precise density and speed of sound measurements at temperatures (293.15 to 328.15) K with 5 K interval. The strength of molecular interactions prevailing in ternary solutions has been discussed on the basis of infinite dilution partial molar volume and partial molar isentropic compression, corresponding volume of transfer and interaction coefficients. Result has been discussed in terms of solute-solute and solute-solvent interactions occurring between ascorbic acid and PIL in ternary solutions (AA + water + PIL). PMID:26009887

  11. Some physical and thermodynamic properties of rocket exhaust clouds measured with infrared scanners

    NASA Technical Reports Server (NTRS)

    Gomberg, R. I.; Kantsios, A. G.; Rosensteel, F. J.

    1977-01-01

    Measurements using infrared scanners were made of the radiation from exhaust clouds from liquid- and solid-propellant rocket boosters. Field measurements from four launches were discussed. These measurements were intended to explore the physical and thermodynamic properties of these exhaust clouds during their formation and subsequent dispersion. Information was obtained concerning the initial cloud's buoyancy, the stabilized cloud's shape and trajectory, the cloud volume as a function of time, and it's initial and stabilized temperatures. Differences in radiation intensities at various wavelengths from ambient and stabilized exhaust clouds were investigated as a method of distinguishing between the two types of clouds. The infrared remote sensing method used can be used at night when visible range cameras are inadequate. Infrared scanning techniques developed in this project can be applied directly to natural clouds, clouds containing certain radionuclides, or clouds of industrial pollution.

  12. Ab initio calculation of the thermodynamic properties of InSb under intense laser irradiation

    SciTech Connect

    Feng, ShiQuan; Cheng, XinLu; Key Laboratory of High Energy Density Physics and Technology of Ministry of Education, Sichuan University, Chengdu, 610064 ; Zhao, JianLing; Zhang, Hong

    2013-07-28

    In this paper, phonon spectra of InSb at different electronic temperatures are presented. Based on the phonon dispersion relationship, we further perform a theoretical investigation of the thermodynamic properties of InSb under intense laser irradiation. The phonon entropy, phonon heat capacity, and phonon contribution to Helmholtz free energy and internal energy of InSb are calculated as functions of temperature at different electronic temperatures. The abrupt change in the phonon entropy- temperature curve from T{sub e} = 0.75 to 1.0 eV provides an indication of InSb undergoing a phase transition from solid to liquid. It can be considered as a collateral evidence of non-thermal melting for InSb under intense electronic excitation effect.

  13. Quantum phase transition and thermodynamic properties of a fourfold magnetic periodic system

    NASA Astrophysics Data System (ADS)

    Wang, Shuling; Li, Ruixue; Ding, Linjie; Fu, Hua-Hua; Zhu, Si-cong; Ni, Yun; Meng, Yan; Yao, Kailun

    2014-12-01

    Based on the experimental synthesis of organic compound verdazyl radical ?-3-(2,6-dichlorophenyl)-1,5-diphenylverdazyl, consisting of four antiferromagnetic couplings, we study the magnetic properties and thermodynamic behaviors for different antiferromagnetic interactions using Green’s function theory. Under different fields, there are five regimes containing two gapless phases and three magnetization plateaus (M=0, 1/2 and saturated magnetization) distinguished by four critical lines, which are evidenced by the two-site entanglement entropy and closely related to the energy spectra. In addition, we calculate the susceptibility and specific heat, to demonstrate the low-lying excitations at low temperatures. It will provide guidance for us to synthesize varieties of unconventional magnetic materials, and stimulate future studies on quantum spin systems.

  14. Thermodynamic and rheological properties of solid-liquid systems in coal processing. Final technical report

    SciTech Connect

    Kabadi, V.N.

    1995-06-30

    The work on this project was initiated on September 1, 1991. The project consisted of two different tasks: (1) Development of a model to compute viscosities of coal derived liquids, and (2) Investigate new models for estimation of thermodynamic properties of solid and liquid compounds of the type that exist in coal, or are encountered during coal processing. As for task 1, a model for viscosity computation of coal model compound liquids and coal derived liquids has been developed. The detailed model is presented in this report. Two papers, the first describing the pure liquid model and the second one discussing the application to coal derived liquids, are expected to be published in Energy & Fuels shortly. Marginal progress is reported on task 2. Literature review for this work included compilation of a number of data sets, critical investigation of data measurement techniques available in the literature, investigation of models for liquid and solid phase thermodynamic computations. During the preliminary stages it was discovered that for development of a liquid or solid state equation of state, accurate predictive models for a number of saturation properties, such as, liquid and solid vapor pressures, saturated liquid and solid volumes, heat capacities of liquids and solids at saturation, etc. Most the remaining time on this task was spent in developing predictive correlations for vapor pressures and saturated liquid volumes of organic liquids in general and coal model liquids in particular. All these developments are discussed in this report. Some recommendations for future direction of research in this area are also listed.

  15. Prediction of thermodynamic properties of coal derivatives. Annual technical report, March 1, 1992--February 28, 1993

    SciTech Connect

    Donohue, M.D.

    1992-11-01

    The purpose of this research program is to understand and model the effect of the different intermolecular forces on the thermodynamic properties of systems containing pure compounds and mixtures. The compounds under consideration vary considerably in size, shape and energy. Therefore in order to develop a theory capable of describing accurately the thermodynamic properties and phase behavior of such systems over a wide range of temperature and pressure, one has to take into account explicitly the differences in shape and size among the various compounds as well as the different type of intermolecular interactions. We have developed equations of state for pure-component chain molecules. We have shown that the excellent performance of complicated theories such as the Generalized Flory Dimer (GFD) theory can be mimicked by simpler equations, if certain assumptions for the shape parameters are made. We developed engineering correlations based on the GFD theory, using local composition theory to take into account the attractive contribution. We compared various methods for the calculation of the repulsive and attractive contributions against computer simulation data for hard and square-well chains, and experimental data from the literature. We also have studied microstructure and local order in fluids that contain asymmetric molecules. In addition, simple cubic equations of state have been applied to calculate physical and chemical-reaction equilibria in non-ideal systems. In order to obtain a better understanding of the intermolecular forces and to test some of our recent models, we have performed considerable experimental work. We used FT-IR to examine the self-association of aliphatic alcohols due to hydrogen bonding. In addition, FT-IR spectroscopy was used to investigate Lewis acid-base interactions between probe and entrainer-cosolvent molecules.

  16. Thermodynamic and Transport Properties of Superconducting Mg{sup 10}B{sub 2}

    SciTech Connect

    Finnemore, D. K.; Ostenson, J. E.; Bud'ko, S. L.; Lapertot, G.; Canfield, P. C.

    2001-03-12

    Transport and thermodynamic properties of a sintered pellet of the newly discovered MgB{sub 2} superconductor have been measured to determine the characteristic critical magnetic fields and critical current densities. Both resistive transition and magnetization data give similar values of the upper critical field, H{sub c2} , with magnetization data giving dH{sub c2}/dT=0.44 T/ K at the transition temperature of T{sub c}=40.2 K . Close to the transition temperature, magnetization curves are thermodynamically reversible, but at low temperatures the trapped flux can be on the order of 1T. The value of dH{sub c}/dT at T{sub c} is estimated to be about 12 mT/K , a value similar to classical superconductors like Sn. Hence, the Ginzburg-Landau parameter {kappa}{approx}26 . Estimates of the critical supercurrent density, J{sub c} , using hysteresis loops and the Bean model, give critical current densities on the order of 10{sup 5} A/cm {sup 2} . Hence the supercurrent coupling through the grain boundaries is comparable to intermetallics like Nb{sub 3}Sn .

  17. Structural, thermodynamic, and electronic properties of plutonium oxides from first principles

    NASA Astrophysics Data System (ADS)

    Jomard, Gérald; Amadon, Bernard; Bottin, François; Torrent, Marc

    2008-08-01

    We report ab initio calculations of the structural, electronic, optical, and thermodynamic properties of plutonium oxides ( PuO2 and ?-Pu2O3 ). In order to describe the basic features of the electronic structure, a method suited to take into account strong local correlations has to be used. We apply the local density approximation/generalized gradient approximation ( LDA/GGA)+U approximations to these compounds and compare them with the calculations of Sun [J. Chem. Phys. 128, 084705 (2008)]. Whereas a good agreement is obtained for PuO2 , our LDA and LDA+U results differ strongly from this study in the case of Pu2O3 . In particular, the effect of the Hubbard parameter U on the volume is qualitatively and quantitatively different. Moreover, thermodynamic quantities differ. We thus focus our study on Pu2O3 and emphasize the importance of a careful and systematic search of the ground state in LDA+U : In particular, different hints for the occupation matrices corresponding to the electronic configurations allowed by symmetry have to be tried. This procedure is absolutely necessary to find the absolute minimum of the energy. Reliable and accurate quantitative results are given for Pu2O3 . We thus recover a more physical behavior coherent with calculations on other systems, such as cerium oxides.

  18. Structure, thermodynamic properties, and phase diagrams of few colloids confined in a spherical pore

    E-print Network

    Iván Paganini; Claudio Pastorino; Ignacio Urrutia

    2015-04-09

    We study a system of few colloids confined in a small spherical cavity by event driven molecular dynamics simulations in the canonical ensemble. The colloidal particles interact through a short range square-well potential, which takes into account the basic elements of attraction and excluded-volume repulsion of the interaction among colloids. We analyze the structural and thermodynamic properties of this few-body confined system in the framework of the theory of inhomogeneous fluids. Pair correlation functions and density profiles across the cavity are used to determine the structure of the system and the spatial characteristics of its inhomogeneities. Pressure on the walls, internal energy and surface quantities such as surface tension and adsorption are also analyzed for the whole range of densities, temperatures and number of particles considered. We have characterized the structure of systems from 2 to 6 confined particles as function of density and temperature, identifying the distinctive qualitative behaviors all over the thermodynamic plane $T-\\rho$ in a few-particle equivalence to phase diagrams of macroscopic systems. Applying the extended law of corresponding states the square well interaction is mapped to the Asakura-Oosawa model for colloid-polymer mixtures. We link explicitly the temperature in the confined square-well fluid to the equivalent packing fraction of polymers in the Asakura-Oosawa model. Using this approach we study the confined system of few colloids in a colloid-polymer mixture.

  19. Structure, thermodynamic properties, and phase diagrams of few colloids confined in a spherical pore.

    PubMed

    Paganini, Iván E; Pastorino, Claudio; Urrutia, Ignacio

    2015-06-28

    We study a system of few colloids confined in a small spherical cavity with event driven molecular dynamics simulations in the canonical ensemble. The colloidal particles interact through a short range square-well potential that takes into account the basic elements of attraction and excluded-volume repulsion of the interaction among colloids. We analyze the structural and thermodynamic properties of this few-body confined system in the framework of inhomogeneous fluids theory. Pair correlation function and density profile are used to determine the structure and the spatial characteristics of the system. Pressure on the walls, internal energy, and surface quantities such as surface tension and adsorption are also analyzed for a wide range of densities and temperatures. We have characterized systems from 2 to 6 confined particles, identifying distinctive qualitative behavior over the thermodynamic plane T - ?, in a few-particle equivalent to phase diagrams of macroscopic systems. Applying the extended law of corresponding states, the square well interaction is mapped to the Asakura-Oosawa model for colloid-polymer mixtures. We link explicitly the temperature of the confined square-well fluid to the equivalent packing fraction of polymers in the Asakura-Oosawa model. Using this approach, we study the confined system of few colloids in a colloid-polymer mixture. PMID:26133449

  20. Structure, thermodynamic properties, and phase diagrams of few colloids confined in a spherical pore

    NASA Astrophysics Data System (ADS)

    Paganini, Iván E.; Pastorino, Claudio; Urrutia, Ignacio

    2015-06-01

    We study a system of few colloids confined in a small spherical cavity with event driven molecular dynamics simulations in the canonical ensemble. The colloidal particles interact through a short range square-well potential that takes into account the basic elements of attraction and excluded-volume repulsion of the interaction among colloids. We analyze the structural and thermodynamic properties of this few-body confined system in the framework of inhomogeneous fluids theory. Pair correlation function and density profile are used to determine the structure and the spatial characteristics of the system. Pressure on the walls, internal energy, and surface quantities such as surface tension and adsorption are also analyzed for a wide range of densities and temperatures. We have characterized systems from 2 to 6 confined particles, identifying distinctive qualitative behavior over the thermodynamic plane T - ?, in a few-particle equivalent to phase diagrams of macroscopic systems. Applying the extended law of corresponding states, the square well interaction is mapped to the Asakura-Oosawa model for colloid-polymer mixtures. We link explicitly the temperature of the confined square-well fluid to the equivalent packing fraction of polymers in the Asakura-Oosawa model. Using this approach, we study the confined system of few colloids in a colloid-polymer mixture.

  1. Denatured State Structural Property Determines Protein Stabilization by Macromolecular Crowding: A Thermodynamic and Structural Approach

    PubMed Central

    Mittal, Shruti; Singh, Laishram Rajendrakumar

    2013-01-01

    Understanding of protein structure and stability gained to date has been acquired through investigations made under dilute conditions where total macromolecular concentration never surpasses 10 g l?1. However, biological macromolecules are known to evolve and function under crowded intracellular environments that comprises of proteins, nucleic acids, ribosomes and carbohydrates etc. Crowded environment is known to result in altered biological properties including thermodynamic, structural and functional aspect of macromolecules as compared to the macromolecules present in our commonly used experimental dilute buffers (for example, Tris HCl or phosphate buffer). In this study, we have investigated the thermodynamic and structural consequences of synthetic crowding agent (Ficoll 70) on three different proteins (Ribonuclease-A, lysozyme and holo ?-lactalbumin) at different pH values. We report here that the effect of crowding is protein dependent in terms of protein thermal stability and structure. We also observed that the structural characteristics of the denatured state determines if crowding will have an effect or not on the protein stability. PMID:24265729

  2. The thermodynamic properties of hydrated ?-Al{sub 2}O{sub 3} nanoparticles

    SciTech Connect

    Spencer, Elinor C.; Ross, Nancy L.; Huang, Baiyu; Woodfield, Brian F.; Parker, Stewart F.; Kolesnikov, Alexander I.

    2013-12-28

    In this paper we report a combined calorimetric and inelastic neutron scattering (INS) study of hydrated ?-Al{sub 2}O{sub 3} (?-alumina) nanoparticles. These complementary techniques have enabled a comprehensive evaluation of the thermodynamic properties of this technological and industrially important metal oxide to be achieved. The isobaric heat capacity (C{sub p}) data presented herein provide further critical insights into the much-debated chemical composition of ?-alumina nanoparticles. Furthermore, the isochoric heat capacity (C{sub v}) of the surface water, which is so essential to the stability of all metal-oxides at the nanoscale, has been extracted from the high-resolution INS data and differs significantly from that of ice?Ih due to the dominating influence of strong surface-water interactions. This study also encompassed the analysis of four ?-alumina samples with differing pore diameters [4.5 (1), 13.8 (2), 17.9 (3), and 27.2 nm (4)], and the results obtained allow us to unambiguously conclude that the water content and pore size have no influence on the thermodynamic behaviour of hydrated ?-alumina nanoparticles.

  3. First-principles calculations on the elastic and thermodynamic properties of NbN

    NASA Astrophysics Data System (ADS)

    Ren, Da-Hua; Cheng, Xin-Lu

    2012-12-01

    The elastic and thermodynamic properties of NbN at high pressures and high temperatures are investigated by the plane-wave pseudopotential density functional theory (DFT). The generalized gradient approximation (GGA) with the Perdew—Burke—Ernzerhof (PBE) method is used to describe the exchange—correlation energy in the present work. The calculated equilibrium lattice constant a0, bulk modulus B0, and the pressure derivative of bulk modulus B'0 of NbN with rocksalt structure are in good agreement with numerous experimental and theoretical data. The elastic properties over a range of pressures from 0 to 80.4 GPa are obtained. Isotropic wave velocities and anisotropic elasticity of NbN are studied in detail. It is indicated that NbN is highly anisotropic in both longitudinal and shear-wave velocities. According to the quasi-harmonic Debye model, in which the phononic effect is considered, the relations of (V - V0)/V0 to the temperature and the pressure, and the relations of the heat capacity Cv and the thermal expansion coefficient ? to temperature are discussed in a pressure range from 0 to 80.4 GPa and a temperature range from 0 to 2500 K. At low temperature, Cv is proportional to T3 and tends to the Dulong—Petit limit at higher temperature. We predict that the thermal expansion coefficient ? of NbN is about 4.20 × 10-6/K at 300 K and 0 GPa.

  4. First principle study of elastic and thermodynamic properties of FeB4 under high pressure

    NASA Astrophysics Data System (ADS)

    Zhang, Xinyu; Qin, Jiaqian; Ning, Jinliang; Sun, Xiaowei; Li, Xinting; Ma, Mingzhen; Liu, Riping

    2013-11-01

    The elastic properties, elastic anisotropy, and thermodynamic properties of the lately synthesized orthorhombic FeB4 at high pressures are investigated using first-principles density functional calculations. The calculated equilibrium parameters are in good agreement with the available experimental and theoretical data. The obtained normalized volume dependence of high pressure is consistent with the previous experimental data investigated using high-pressure synchrotron x-ray diffraction. The complete elastic tensors and crystal anisotropies of the FeB4 are also determined in the pressure range of 0-100 GPa. By the elastic stability criteria and vibrational frequencies, it is predicted that the orthorhombic FeB4 is stable up to 100 GPa. In addition, the calculated B/G ratio reveals that FeB4 possesses brittle nature in the range of pressure from 0 to 100 GPa. The calculated elastic anisotropic factors suggest that FeB4 is elastically anisotropic. By using quasi-harmonic Debye model, the compressibility, bulk modulus, the coefficient of thermal expansion, the heat capacity, and the Grüneisen parameter of FeB4 are successfully obtained in the present work.

  5. Influence of volume magnetostriction on the thermodynamic properties of Ni-Mn-Ga shape memory alloys

    NASA Astrophysics Data System (ADS)

    Kosogor, Anna; L'vov, Victor A.; Cesari, Eduard

    2015-10-01

    In the present article, the thermodynamic properties of Ni-Mn-Ga ferromagnetic shape memory alloys exhibiting the martensitic transformations (MTs) above and below Curie temperature are compared. It is shown that when MT goes below Curie temperature, the elastic and thermal properties of alloy noticeably depend on magnetization value due to spontaneous volume magnetostriction. However, the separation of magnetic parts from the basic characteristics of MT is a difficult task, because the volume magnetostriction does not qualitatively change the transformational behaviour of alloy. This problem is solved for several Ni-Mn-Ga alloys by means of the quantitative theoretical analysis of experimental data obtained in the course of stress-strain tests. For each alloy, the entropy change and the transformation heat evolved in the course of MT are evaluated, first, from the results of stress-strain tests and, second, from differential scanning calorimetry data. For all alloys, a quantitative agreement between the values obtained in two different ways is observed. It is shown that the magnetic part of transformation heat exceeds the non-magnetic one for the Ni-Mn-Ga alloys undergoing MTs in ferromagnetic state, while the elevated values of transformation heat measured for the alloys undergoing MTs in paramagnetic state are caused by large MT strains.

  6. Thermodynamic and structure-property study of liquid-vapor equilibrium for aroma compounds.

    PubMed

    Tromelin, Anne; Andriot, Isabelle; Kopjar, Mirela; Guichard, Elisabeth

    2010-04-14

    Thermodynamic parameters (T, DeltaH degrees , DeltaS degrees , K) were collected from the literature and/or calculated for five esters, four ketones, two aldehydes, and three alcohols, pure compounds and compounds in aqueous solution. Examination of correlations between these parameters and the range values of DeltaH degrees and DeltaS degrees puts forward the key roles of enthalpy for vaporization of pure compounds and of entropy in liquid-vapor equilibrium of compounds in aqueous solution. A structure-property relationship (SPR) study was performed using molecular descriptors on aroma compounds to better understand their vaporization behavior. In addition to the role of polarity for vapor-liquid equilibrium of compounds in aqueous solution, the structure-property study points out the role of chain length and branching, illustrated by the correlation between the connectivity index CHI-V-1 and the difference between T and log K for vaporization of pure compounds and compounds in aqueous solution. Moreover, examination of the esters' enthalpy values allowed a probable conformation adopted by ethyl octanoate in aqueous solution to be proposed. PMID:20222661

  7. Simultaneous calibration of end-member thermodynamic data and solution properties with correlated uncertainties

    NASA Astrophysics Data System (ADS)

    Antoshechkina, P. M.; Wolf, A. S.; Hamecher, E. A.; Asimow, P. D.; Ghiorso, M. S.

    2013-12-01

    Community databases such as EarthChem, LEPR, and AMCSD both increase demand for quantitative petrological tools, including thermodynamic models like the MELTS family of algorithms, and are invaluable in development of such tools. The need to extend existing solid solution models to include minor components such as Cr and Na has been evident for years but as the number of components increases it becomes impossible to completely separate derivation of end-member thermodynamic data from calibration of solution properties. In Hamecher et al. (2012; 2013) we developed a calibration scheme that directly interfaces with a MySQL database based on LEPR, with volume data from AMCSD and elsewhere. Here we combine that scheme with a Bayesian approach, where independent constraints on parameter values (e.g. existence of miscibility gaps) are combined with uncertainty propagation to give a more reliable best-fit along with associated model uncertainties. We illustrate the scheme with a new model of molar volume for (Ca,Fe,Mg,Mn,Na)3(Al,Cr,Fe3+,Fe2+,Mg,Mn,Si,Ti)2Si3O12 cubic garnets. For a garnet in this chemical system, the model molar volume is obtained by adding excess volume terms to a linear combination of nine independent end-member volumes. The model calibration is broken into three main stages: (1) estimation of individual end-member thermodynamic properties; (2) calibration of standard state volumes for all available independent and dependent end members; (3) fitting of binary and mixed composition data. For each calibration step, the goodness-of-fit includes weighted residuals as well as ?2-like penalty terms representing the (not necessarily Gaussian) prior constraints on parameter values. Using the Bayesian approach, uncertainties are correctly propagated forward to subsequent steps, allowing determination of final parameter values and correlated uncertainties that account for the entire calibration process. For the aluminosilicate garnets, optimal values of the bulk modulus and its pressure derivative are obtained by fitting published compression data using the Vinet equation of state, with the Mie-Grüneisen-Debye thermal pressure formalism to model thermal expansion. End-member thermal parameters are obtained by fitting volume data while ensuring that the heat capacity is consistent with the thermodynamic database of Berman and co-workers. For other end members, data for related compositions are used where such data exist; otherwise ultrasonic data or density functional theory results are taken or, for thermal parameters, systematics in cation radii are used. In stages (2) and (3) the remaining data at ambient conditions are fit. Using this step-wise calibration scheme, most parameters are modified little by subsequent calibration steps but some, such as the standard state volume of the Ti-bearing end member, can vary within calculated uncertainties. The final model satisfies desired criteria and fits almost all the data (more than 1000 points); only excess parameters that are justified by the data are activated. The scheme can be easily extended to calibration of end-member and solution properties from experimental phase equilibria. As a first step we obtain the internally consistent standard state entropy and enthalpy of formation for knorringite and discuss differences between our results and those of Klemme and co-workers.

  8. Thermodynamic properties of a spin-1/2 spin-liquid state in a -type organic salt

    E-print Network

    Loss, Daniel

    LETTERS Thermodynamic properties of a spin-1/2 spin-liquid state in a -type organic salt SATOSHI-based organic charge-transfer salt -(BEDT-TTF)2Cu2(CN)3, with a triangular lattice structure down to 75 m-dimensional triangular lattice is still unclear. The -type salts consisting of BEDT-TTF donors show an interesting phase

  9. Thermodynamic properties of solid palladium-silver alloys and other alloys are investigated by torsion-effusion technique

    NASA Technical Reports Server (NTRS)

    Myles, K. M.

    1967-01-01

    Vapor pressure data obtained by the torsion-effusion method provides the thermodynamic properties of several transition-metal alloy systems. The vapor pressure of silver over solid silver and over palladium-silver alloys was measured and the results were more accurate than those found previously by other techniques.

  10. PHYSICAL REVIEW B 83, 144113 (2011) Structural and thermodynamic properties of compressed palladium: Ab initio and molecular

    E-print Network

    Alfè, Dario

    2011-01-01

    PHYSICAL REVIEW B 83, 144113 (2011) Structural and thermodynamic properties of compressed palladiumRevB.83.144113 PACS number(s): 05.70.-a, 65.40.-b, 62.20.-x, 74.10.+v I. INTRODUCTION Palladium has a wide systems and nanoscale devices fully highlighted the key role that palladium plays.3 For bulk systems

  11. Thermodynamic properties of autunite, uranyl hydrogen phosphate, and uranyl orthophosphate from solubility and calorimetric measurements

    SciTech Connect

    Gorman-Lewis, Drew; Shareva, Tatiana; kubatko, Karrie-Ann; burns, Peter; Wellman, Dawn M.; McNamara, Bruce K.; szymanowski, jennifer; Navrotsky, Alexandra; Fein, Jeremy B.

    2009-10-01

    In this study, we use solubility and oxide melt solution calorimetry measurements to determine the thermodynamic properties of the uranyl phosphate phases autunite (abbreviated: CaUP), uranyl hydrogen phosphate (HUP), and uranyl orthophosphate (UP). Solubility measurements from both supersaturated and undersaturated conditions, as well as under different pH conditions, rigorously demonstrate attainment of equilibrium and yield well-constrained solubility product values of -48.36 (-0.03 /+ 0.03), -13.17 (-0.11 / +0.07), and -49.36 (-0.04 / +0.02) for CaUP, HUP, and UP, respectively. We use the solubility data to calculate standard state Gibbs free energies of formation for all phases (-7630.61 ± 9.69, -3072.27 ± 4.76, and -6138.95 ± 12.24 kJ mol-1 for CaUP, HUP, and UP, respectively), and calorimetry data to calculate standard state enthalpies of formation of -3223.22 ± 4.00 and -7001.01 ± 15.10 kJ mol-1 for HUP and UP, respectively. Combining these results allows us also to calculate the standard state entropies of formation of -506.54 ± 10.48 and -2893.12 ± 19.44 kJ mol-1 K-1 for HUP and UP phases, respectively. The results from this study are part of a combined effort to develop reliable and internally consistent thermodynamic data for environmentally relevant uranyl minerals. Data such as these are required in order to optimize and quantitatively assess the effect of phosphate amendment remediation technologies for uranium contaminated systems.

  12. Entropy and enthalpy calculations from perturbation and integration thermodynamics methods using molecular dynamics simulations: applications to the calculation of hydration and association thermodynamic properties

    NASA Astrophysics Data System (ADS)

    Ghoufi, Aziz; Malfreyt, Patrice

    Calculation of association thermodynamic properties using molecular simulation is essential in computational chemistry. In the case of good agreement with the experimental thermodynamic binding properties, this type of calculation may complement experimental works by providing a microscopic view of the association process. Whereas the calculation of the free energy of association is nowadays well controlled, the calculation of the enthalpy and entropy of association remains difficult in most cases, especially as the association involves hosts and guests of biological interest. A novel method for calculating the entropy change from a molecular dynamics simulation is described. Within the theoretical framework, we discuss the different approximations leading to the final stage of the operational expressions of ?G and ?H in the NpT ensemble and we establish an expression for ?S using the Free Energy Perturbation (FEP) formalism in this statistical ensemble. Finally, we illustrate the theoretical considerations by calculations of the hydration entropy changes between cations of different masses and charges. We extend the study by calculating the changes in the thermodynamic properties of association of inorganic cations with a macrocycle of biological interest.

  13. Calculation of thermodynamic properties of dense fluid neon using statistical-mechanical perturbation theory

    NASA Astrophysics Data System (ADS)

    Kortbeek, P. J.; Ten Seldam, C. A.; Schouten, J. A.

    The theory and potentials described in the preceding paper are used for the calculation of thermodynamic properties of fluid neon between 73 and 348 K and up to the melting line. A polynomial equation of state for correlating the densities between 73 and 323 K and between 30 MPa and 1 GPa is presented. The calculations have been extended up to 6 GPa and the performance of the EXP-6 effective pair potential and the HFD-C2, HFD-B and XC3 pure pair potentials is compared. The effect of the Axilrod-Teller many-body correction term on the pure pair potentials is studied. In the ranges 98-348 K and 0·6-6 GPa the density data are correlated by a MBWR equation of state, and a polynomial expression is given for the sound velocity in these ranges. The pressure and temperature dependences of the specific heat at constant volume are shown. A comparison is made between the experimental pVT and soundvelocity data of Kimura et al. at 295 K and up to 3·5 GPa and our calculations.

  14. Comparative Thermodynamic Prediction of Integral Properties of Six Component, Quaternary, and Ternary Systems

    NASA Astrophysics Data System (ADS)

    Dogan, Ali; Arslan, Hüseyin

    2015-08-01

    In the present study, the enthalpies of mixing associated with the liquid phase in Ni-Cr-Co-Al-Ti-Cu, Au-In-Sn-Zn, and In-Pd-Sn systems at a temperature of 2000 K (1727 °C) through the six components, ternary, and quaternary geometric models are calculated. The values calculated from different geometric models are compared with those obtained in the experiments. In this respect, the results of some thermodynamic prediction methods were applied to the six-component Ni-Cr-Co-Al-Ti-Cu system, the quaternary alloy Au-In0.45-Sn0.45-Zn0.1, and the subsystem ternary alloy In-Pd-Sn in the present study in order to analytically determine the integral properties associated with the six-component alloy systems in the liquid phase. The Chou's general solution model and the traditional models of Toop, Colinet, Muggianu, and Kohler were included in the calculation for comparison and discussion. A comparison among the results of the models and experiments carried out for ternary and quaternary systems displays good mutual agreement.

  15. Lattice model of linear telechelic polymer melts. II. Influence of chain stiffness on basic thermodynamic properties

    NASA Astrophysics Data System (ADS)

    Xu, Wen-Sheng; Freed, Karl F.

    2015-07-01

    The lattice cluster theory (LCT) for semiflexible linear telechelic melts, developed in Paper I, is applied to examine the influence of chain stiffness on the average degree of self-assembly and the basic thermodynamic properties of linear telechelic polymer melts. Our calculations imply that chain stiffness promotes self-assembly of linear telechelic polymer melts that assemble on cooling when either polymer volume fraction ? or temperature T is high, but opposes self-assembly when both ? and T are sufficiently low. This allows us to identify a boundary line in the ?-T plane that separates two regions of qualitatively different influence of chain stiffness on self-assembly. The enthalpy and entropy of self-assembly are usually treated as adjustable parameters in classical Flory-Huggins type theories for the equilibrium self-assembly of polymers, but they are demonstrated here to strongly depend on chain stiffness. Moreover, illustrative calculations for the dependence of the entropy density of linear telechelic polymer melts on chain stiffness demonstrate the importance of including semiflexibility within the LCT when exploring the nature of glass formation in models of linear telechelic polymer melts.

  16. Lattice model of linear telechelic polymer melts. II. Influence of chain stiffness on basic thermodynamic properties

    E-print Network

    Wen-Sheng Xu; Karl F. Freed

    2015-06-26

    The lattice cluster theory (LCT) for semiflexible linear telechelic melts, developed in paper I, is applied to examine the influence of chain stiffness on the average degree of self-assembly and the basic thermodynamic properties of linear telechelic polymer melts. Our calculations imply that chain stiffness promotes self-assembly of linear telechelic polymer melts that assemble on cooling when either polymer volume fraction $\\phi$ or temperature $T$ is high, but opposes self-assembly when both $\\phi$ and $T$ are sufficiently low. This allows us to identify a boundary line in the $\\phi$-$T$ plane that separates two regions of qualitatively different influence of chain stiffness on self-assembly. The enthalpy and entropy of self-assembly are usually treated as adjustable parameters in classical Flory-Huggins type theories for the equilibrium self-assembly of polymers, but they are demonstrated here to strongly depend on chain stiffness. Moreover, illustrative calculations for the dependence of the entropy density of linear telechelic polymer melts on chain stiffness demonstrate the importance of including semiflexibility within the LCT when exploring the nature of glass formation in models of linear telechelic polymer melts.

  17. Tables of equation-of-state, thermodynamic properties, and shock Hugoniot for hot dense fluid deuterium

    NASA Astrophysics Data System (ADS)

    Zaghloul, Mofreh R.

    2015-11-01

    We present computational results and tables of the equation-of-state, thermodynamic properties, and shock Hugoniot for hot dense fluid deuterium. The present results are generated using a recently developed chemical model that takes into account different high density effects such as Coulomb interactions among charged particles, partial degeneracy, and intensive short range hard core repulsion. Internal partition functions are evaluated in a statistical-mechanically consistent way implementing recent developments in the literature. The shock Hugoniot curve derived from the present tables is overall in reasonable agreement with the Hugoniot derived from the Nova-laser shock wave experiments on liquid deuterium, showing that deuterium has a significantly higher compressibility than predicted by the SESAME tables or by Path Integral Monte Carlo calculations. Computational results are presented as surface plots for the dissociated fraction, degree of ionization, pressure, and specific internal energy for densities ranging from 0.0001 to 40 g/cm3 and temperatures from 2000 to ˜106 K. Tables for values of the above mentioned quantities in addition to the specific heat at constant pressure, cp, ratio of specific heats, cp/cv, sound speed and Hugoniot curve (for a specific initial state) are presented for practical use.

  18. Phase diagram of oxygen adsorbed on Ni(111) and thermodynamic properties from first-principles

    NASA Astrophysics Data System (ADS)

    Lazo, C.; Keil, F. J.

    2009-06-01

    The thermodynamic properties and the surface phase diagram of O/Ni(111) have been calculated from Metropolis and Wang-Landau Monte Carlo simulations based on lateral interactions derived from density-functional theory (DFT) calculations. The DFT energies were mapped onto an Ising-like Hamiltonian according to the cluster expansion technique formalism. Both fcc and hcp adsorption sites were included in the Hamiltonian. Different criteria were used to evaluate competing parameter sets: cross-validation score CV, Mallow’s Cp statistics, and adjusted R2 statistics. The parameter space was searched using genetic algorithms in order to find optimum parameter sets. The different parameter sets obtained from different criteria lead essentially to the same transition temperatures. Excellent agreement is found when comparing the shape and the stability regions of the theoretical and the experimental (from the literature) phase diagrams. We investigate the nature of the p(2×2) and (3×3)R30° phase transitions at ?=1/4 and 1/3 ML, respectively. Differences arise when comparing the values of the calculated and the experimental transition temperatures owing to imprecision in present-day DFT calculations.

  19. Determination of thermodynamic properties of poly (cyclohexyl methacrylate) by inverse gas chromatography.

    PubMed

    Kaya, Ismet; Pala, Cigdem Yigit

    2014-07-01

    In this work, some thermodynamic properties of poly (cyclohexyl methacrylate) were studied by inverse gas chromatography (IGC). For this purpose, the polymeric substance was coated on Chromosorb W and which was filled into a glass column. The retention times (t(r)) of the probes were determined from the interactions of poly (cyclohexyl methacrylate) with n-pentane, n-hexane, n-heptane, n-octane, n-decane, methanol, ethanol, 2-propanol, butanol, acetone, ethyl methyl ketone, benzene, toluene and o-xylene by IGC technique. Then, the specific volume (Vg(0)) was determined for each probe molecule. By using (1/T; lnVg(0)) graphics, the glass transition temperature of poly (cyclohexyl methacrylate) was found to be 373 K. The adsorption heat under the glass transition temperature (deltaH(a)), and partial molar heat of sorption above the glass transition (deltaH1(S)), partial molar free energy of sorption (deltaG1(S)) and partial molar entropy of sorption (deltaS1(S)) belonging to sorption for every probe were calculated. The partial molar heat of mixing at infinite dilution (deltaH1(infinity)), partial molar free energy of mixing at infinite dilution (deltaG1(infinity)), Flory-Huggins interaction parameter (chi12(infinity)) and weight fraction activity coefficient (a1/w1)(infinity) values of polymer-solute systems were calculated at different column temperatures. The solubility parameters (delta2) of the polymer were obtained by IGC technique. PMID:25255568

  20. Magnetic and thermodynamic properties of face-centered cubic Fe-Ni alloys.

    PubMed

    Lavrentiev, M Yu; Wróbel, J S; Nguyen-Manh, D; Dudarev, S L

    2014-08-14

    A model lattice ab initio parameterized Heisenberg-Landau magnetic cluster expansion Hamiltonian spanning a broad range of alloy compositions and a large variety of chemical and magnetic configurations has been developed for face-centered cubic Fe-Ni alloys. The thermodynamic and magnetic properties of the alloys are explored using configuration and magnetic Monte Carlo simulations over a temperature range extending well over 1000 K. The predicted face-centered cubic-body-centered cubic coexistence curve, the phase stability of ordered Fe3Ni, FeNi, and FeNi3 intermetallic compounds, and the predicted temperatures of magnetic transitions simulated as functions of alloy composition agree well with experimental observations. Simulations show that magnetic interactions stabilize the face-centered cubic phase of Fe-Ni alloys. Both the model Hamiltonian simulations and ab initio data exhibit a particularly large number of magnetic configurations in a relatively narrow range of alloy compositions corresponding to the occurrence of the Invar effect. PMID:24964377

  1. Mechanical, electronic, and thermodynamic properties of zirconium carbide from first-principles calculations

    NASA Astrophysics Data System (ADS)

    Yang, Xiao-Yong; Lu, Yong; Zheng, Fa-Wei; Zhang, Ping

    2015-11-01

    Mechanical, electronic, and thermodynamic properties of zirconium carbide have been systematically studied using the ab initio calculations. The calculated equilibrium lattice parameter, bulk modulus, and elastic constants are all well consistent with the experimental data. The electronic band structure indicates that the mixture of C 2p and Zr 4d and 4p orbitals around the Fermi level makes a large covalent contribution to the chemical bonds between the C and Zr atoms. The Bader charge analysis suggests that there are about 1.71 electrons transferred from each Zr atom to its nearest C atom. Therefore, the Zr–C bond displays a mixed ionic/covalent character. The calculated phonon dispersions of ZrC are stable, coinciding with the experimental measurement. A drastic expansion in the volume of ZrC is seen with increasing temperature, while the bulk modulus decreases linearly. Based on the calculated phonon dispersion curves and within the quasi-harmonic approximation, the temperature dependence of the heat capacities is obtained, which gives a good description compared with the available experimental data. Project supported by the National Natural Science Foundation of China (Grant No. 51071032).

  2. Principal thermodynamic properties of quasi-two-dimensional carriers under in-plane magnetic field

    NASA Astrophysics Data System (ADS)

    Simserides, Constantinos

    2009-01-01

    An external magnetic field, H, applied parallel to a quasi-two-dimensional carrier system modifies quantitatively and qualitatively the density of states. We examine how this affects primary thermodynamic properties, namely, the entropy, S, the internal and free energy, U and F, the magnetization, M, and the magnetic susceptibility, ?m, using a self-consistent numerical approach. Although M is mainly in the opposite direction to H, the system is not linear. Hence, surprisingly, \\partial M / \\partial H swings between negative and positive values, i.e. a diamagnetic to paramagnetic transition of entirely orbital origin is predicted. This phenomenon is important compared to the ideal de Haas-van Alphen effect, i.e. the corresponding phenomenon under perpendicular magnetic field. By augmenting temperature, the diamagnetic to paramagnetic transition fades away. The overall behaviour of entropy is also foreseen and consistently interpreted. While the entropy contribution to the free energy is very small at low temperatures, entropy shows a clear dependence on the external magnetic field.

  3. Thermodynamic Properties of He Gas in the Temperature Range 4.2-10 K

    NASA Astrophysics Data System (ADS)

    Mosameh, S. M.; Sandouqa, A. S.; Ghassib, H. B.; Joudeh, B. R.

    2014-05-01

    The thermodynamic properties of He gas are investigated in the temperature-range 4.2-10 K, with special emphasis on the second virial coefficient in both the classical and quantum regimes. The main input in computing the quantum coefficient is the `effective' phase shifts. These are calculated within the framework of the Galitskii-Migdal-Feynman (GMF) formalism, using the HFDHE2 and Sposito potentials. The virial equation of state is constructed. Extensive calculations are carried out for the pressure-volume-temperature (P-V-T) behavior, as well as chemical potential, and nonideality of the system. The following results are obtained. First, the validity of the GMF formalism for the present system is demonstrated beyond any doubt. Second, the boiling point (phase-transition point) of He gas is determined from the P-V behavior using the virial equation of state, its value being closest than all previous results to the experimental value. Third, the chemical potential is evaluated from the quantum second virial coefficient. It is found that increases (becomes less negative) as the temperature decreases or the number density n increases. Further, shows no sensitivity to the differences between the potentials used up to n = 10 m. Finally, the compressibility Z is computed and discussed as a measure of the nonideality of the system.

  4. Lattice model of linear telechelic polymer melts. II. Influence of chain stiffness on basic thermodynamic properties.

    PubMed

    Xu, Wen-Sheng; Freed, Karl F

    2015-07-14

    The lattice cluster theory (LCT) for semiflexible linear telechelic melts, developed in Paper I, is applied to examine the influence of chain stiffness on the average degree of self-assembly and the basic thermodynamic properties of linear telechelic polymer melts. Our calculations imply that chain stiffness promotes self-assembly of linear telechelic polymer melts that assemble on cooling when either polymer volume fraction ? or temperature T is high, but opposes self-assembly when both ? and T are sufficiently low. This allows us to identify a boundary line in the ?-T plane that separates two regions of qualitatively different influence of chain stiffness on self-assembly. The enthalpy and entropy of self-assembly are usually treated as adjustable parameters in classical Flory-Huggins type theories for the equilibrium self-assembly of polymers, but they are demonstrated here to strongly depend on chain stiffness. Moreover, illustrative calculations for the dependence of the entropy density of linear telechelic polymer melts on chain stiffness demonstrate the importance of including semiflexibility within the LCT when exploring the nature of glass formation in models of linear telechelic polymer melts. PMID:26178122

  5. Thermodynamics of A?16-21 dissociation from a fibril: Enthalpy, entropy, and volumetric properties.

    PubMed

    Rao Jampani, Srinivasa; Mahmoudinobar, Farbod; Su, Zhaoqian; Dias, Cristiano L

    2015-11-01

    Here, we provide insights into the thermodynamic properties of A ?16-21 dissociation from an amyloid fibril using all-atom molecular dynamics simulations in explicit water. An umbrella sampling protocol is used to compute potentials of mean force (PMF) as a function of the distance ? between centers-of-mass of the A ?16-21 peptide and the preformed fibril at nine temperatures. Changes in the enthalpy and the entropic energy are determined from the temperature dependence of these PMF(s) and the average volume of the simulation box is computed as a function of ?. We find that the PMF at 310 K is dominated by enthalpy while the entropic energy does not change significantly during dissociation. The volume of the system decreases during dissociation. Moreover, the magnitude of this volume change also decreases with increasing temperature. By defining dock and lock states using the solvent accessible surface area (SASA), we find that the behavior of the electrostatic energy is different in these two states. It increases (unfavorable) and decreases (favorable) during dissociation in lock and dock states, respectively, while the energy due to Lennard-Jones interactions increases continuously in these states. Our simulations also highlight the importance of hydrophobic interactions in accounting for the stability of A ?16-21. Proteins 2015; 83:1963-1972. © 2015 Wiley Periodicals, Inc. PMID:26264694

  6. Physical Properties Models for Simulation of Processes to Treat INEEL Tank Farm Waste: Thermodynamic Equilibrium

    SciTech Connect

    Nichols, T.T.; Taylor, D.D.

    2002-07-18

    A status is presented of the development during FY2002 of a database for physical properties models for the simulation of the treatment of Sodium-Bearing Waste (SBW) at the Idaho National Engineering and Environmental Laboratory. An activity coefficient model is needed for concentrated, aqueous, multi-electrolyte solutions that can be used by process design practitioners. Reasonable first-order estimates of activity coefficients in the relevant media are needed rather than an incremental improvement in theoretical approaches which are not usable by practitioners. A comparison of the Electrolyte Non-Random Two-Liquid (ENRTL) and Pitzer ion-interaction models for the thermodynamic representation of SBW is presented. It is concluded that Pitzer's model is superior to ENRTL in modeling treatment processes for SBW. The applicability of the Pitzer treatment to high concentrations of pertinent species and to the determination of solubilities and chemical equilibria is addressed. Alternate values of Pitzer parameters for HCl, H2SO4, and HNO3 are proposed, applicable up to 16m, and 12m, respectively. Partial validation of the implementation of Pitzer's treatment within the commercial process simulator ASPEN Plus was performed.

  7. Calculation of Derivative Thermodynamic Hydration and Aqueous Partial Molar Properties of Ions Based on Atomistic Simulations.

    PubMed

    Dahlgren, Björn; Reif, Maria M; Hünenberger, Philippe H; Hansen, Niels

    2012-10-01

    The raw ionic solvation free energies calculated on the basis of atomistic (explicit-solvent) simulations are extremely sensitive to the boundary conditions and treatment of electrostatic interactions used during these simulations. However, as shown recently [Kastenholz, M. A.; Hünenberger, P. H. J. Chem. Phys.2006, 124, 224501 and Reif, M. M.; Hünenberger, P. H. J. Chem. Phys.2011, 134, 144104], the application of an appropriate correction scheme allows for a conversion of the methodology-dependent raw data into methodology-independent results. In this work, methodology-independent derivative thermodynamic hydration and aqueous partial molar properties are calculated for the Na(+) and Cl(-) ions at P° = 1 bar and T(-) = 298.15 K, based on the SPC water model and on ion-solvent Lennard-Jones interaction coefficients previously reoptimized against experimental hydration free energies. The hydration parameters considered are the hydration free energy and enthalpy. The aqueous partial molar parameters considered are the partial molar entropy, volume, heat capacity, volume-compressibility, and volume-expansivity. Two alternative calculation methods are employed to access these properties. Method I relies on the difference in average volume and energy between two aqueous systems involving the same number of water molecules, either in the absence or in the presence of the ion, along with variations of these differences corresponding to finite pressure or/and temperature changes. Method II relies on the calculation of the hydration free energy of the ion, along with variations of this free energy corresponding to finite pressure or/and temperature changes. Both methods are used considering two distinct variants in the application of the correction scheme. In variant A, the raw values from the simulations are corrected after the application of finite difference in pressure or/and temperature, based on correction terms specifically designed for derivative parameters at P° and T(-). In variant B, these raw values are corrected prior to differentiation, based on corresponding correction terms appropriate for the different simulation pressures P and temperatures T. The results corresponding to the different calculation schemes show that, except for the hydration free energy itself, accurate methodological independence and quantitative agreement with even the most reliable experimental parameters (ion-pair properties) are not yet reached. Nevertheless, approximate internal consistency and qualitative agreement with experimental results can be achieved, but only when an appropriate correction scheme is applied, along with a careful consideration of standard-state issues. In this sense, the main merit of the present study is to set a clear framework for these types of calculations and to point toward directions for future improvements, with the ultimate goal of reaching a consistent and quantitative description of single-ion hydration thermodynamics in molecular dynamics simulations. PMID:26593002

  8. Steam Properties Database

    National Institute of Standards and Technology Data Gateway

    SRD 10 NIST/ASME Steam Properties Database (PC database for purchase)   Based upon the International Association for the Properties of Water and Steam (IAPWS) 1995 formulation for the thermodynamic properties of water and the most recent IAPWS formulations for transport and other properties, this updated version provides water properties over a wide range of conditions according to the accepted international standards.

  9. Polylogarithmic Representation of Radiative and Thermodynamic Properties of Thermal Radiation in a Given Spectral Range: I. Blackbody Radiation

    NASA Astrophysics Data System (ADS)

    Fisenko, Anatoliy I.; Lemberg, Vladimir

    2015-07-01

    The thermodynamics of blackbody radiation has been constructed for the entire range of the spectrum. However, in practical applications, thermodynamic functions must be calculated within a finite range of frequencies. The analytical expressions for the radiative and thermodynamic properties of blackbody radiation over an arbitrary spectral range of the electromagnetic spectrum are obtained. The Wien displacement law, Stefan-Boltzmann law, total energy density, number density of photons, Helmholtz free energy density, internal energy density, enthalpy density, entropy density, heat capacity at constant volume, and pressure are expressed in terms of the polylogarithm functions. These expressions are important when we build a theoretical model of radiative heat transfer, for example. The thermodynamic functions of blackbody radiation are calculated for various ranges of the spectrum at different temperatures. As an example of practical applications, thermodynamics of the cosmic microwave background radiation measured by the COBE FIRAS instrument is constructed. The expressions obtained for the radiative and thermodynamic functions of blackbody radiation can easily be presented in wavelength and wavenumber domains.

  10. Resources in the VLab Science Gateway: Online applications for thermodynamics and thermal elastic properties of mantle minerals

    NASA Astrophysics Data System (ADS)

    Wentzcovitch, R. M.; Da Silveira, P. R.; Wu, Z.; Yu, Y.

    2013-12-01

    Today first principles calculations in mineral physics play a fundamental role in understanding of the Earth. They complement experiments by expanding the pressure and temperature range for which properties can be obtained and provide access to atomic scale phenomena. Since the wealth of predictive first principles results can hardly be communicated in printed form, we have developed online applications where published results can be reproduced/verified online and extensive unpublished results can be generated in customized form. So far these applications have included thermodynamics properties of end-member phases and thermal elastic properties of end-member phases and few solid solutions. Extension of this software infrastructure to include other properties is in principle straightforward. This contribution will review the nature of results that can be generated (methods, thermodynamics domain, list of minerals, properties, etc) and nature of the software infrastructure. These applications are part of a more extensive cyber-infrastructure operating in the XSEDE - the VLab Science Gateway [1]. [1] https://www.xsede.org/web/guest/gateways-listing Research supported by NSF grants ATM-0428744 and EAR-1047629.

  11. Thermodynamic properties and equations of state for Ag, Al, Au, Cu and MgO using a lattice vibrational method

    NASA Astrophysics Data System (ADS)

    Jacobs, M.; Schmid-Fetzer, R.

    2012-04-01

    A prerequisite for the determination of pressure in static high pressure measurements, such as in diamond anvil cells is the availability of accurate equations of state for reference materials. These materials serve as luminescence gauges or as X-ray gauges and equations of state for these materials serve as secondary pressure scales. Recently, successful progress has been made in the development of consistency between static, dynamic shock-wave and ultrasonic measurements of equations of state (e.g. Dewaele et al. Phys. Rev. B70, 094112, 2004, Dorogokupets and Oganov, Doklady Earth Sciences, 410, 1091-1095, 2006, Holzapfel, High Pressure Research 30, 372-394, 2010) allowing testing models to arrive at consistent thermodynamic descriptions for X-ray gauges. Apart from applications of metallic elements in high-pressure work, thermodynamic properties of metallic elements are also of mandatory interest in the field of metallurgy for studying phase equilibria of alloys, kinetics of phase transformation and diffusion related problems, requiring accurate thermodynamic properties in the low pressure regime. Our aim is to develop a thermodynamic data base for metallic alloy systems containing Ag, Al, Au, Cu, Fe, Ni, Pt, from which volume properties in P-T space can be predicted when it is coupled to vibrational models. This mandates the description of metallic elements as a first step aiming not only at consistency in the pressure scales for the elements, but also at accurate representations of thermodynamic properties in the low pressure regime commonly addressed in metallurgical applications. In previous works (e.g. Jacobs and de Jong, Geochim. Cosmochim. Acta, 71, 3630-3655, 2007, Jacobs and van den Berg, Phys. Earth Planet. Inter., 186, 36-48, 2011) it was demonstrated that a lattice vibrational framework based on Kieffer's model for the vibrational density of states, is suitable to construct a thermodynamic database for Earth mantle materials. Such a database aims at, when coupled to a thermodynamic computation program, the calculation and prediction of phase equilibria and thermo-physical properties of phase equilibrium assemblages in pressure-temperature-composition space. In Jacobs and van den Berg (2011) the vibrational method, together with a thermodynamic data base, was successfully applied to mantle convection of materials in the Earth. These works demonstrate that the vibrational method has the advantages of (1) computational speed, (2) coupling or making comparisons with ab initio methods and (3) making reliable extrapolations to extreme conditions. We present results of thermodynamic analyses, using lattice vibrational methods, of Ag, Al, Au, Cu and MgO covering the pressure and temperature regime of the Earth's interior. We show results on consistency of the pressure scales for these materials using different equations of state, under the constraint that thermodynamic properties in the low-pressure regime are accurately represented.

  12. Thermodynamic properties of CexTh1-xO2 solid solution from first-principles calculations

    SciTech Connect

    Xiao, Haiyan Y.; Zhang, Yanwen; Weber, William J.

    2012-11-02

    A systematic study based on first-principles calculations along with a quasi-harmonic approximation has been conducted to calculate the thermodynamic properties of the CexTh1xO2 solid solution. The predicted density, thermal expansion coefficients, heat capacity and thermal conductivity for the CexTh1xO2 solid solution all agree well with the available experimental data. The thermal expansion coefficient for ThO2 increases with CeO2 substitution, and complete substitution shows the highest expansion coefficient. On the other hand, the mixed CexTh1xO2 (0 < x < 1) solid solution generally exhibits lower heat capacity and thermal conductivity than the ThO2 and CeO2 end members. Our calculations indicate a strong effect of Ce concentration on the thermodynamic properties of the CexTh1xO2 solid solution.

  13. Thermodynamic properties of CexTh1-xO2 solid solution from first-principles calculations

    SciTech Connect

    Xiao, Haiyan; Zhang, Yanwen; Weber, William J

    2013-01-01

    A systematic study based on first-principles calculations along with the quasi-harmonic approximation has been conducted to calculate the thermodynamic properties of the CexTh1-xO2 solid solution. The predicted density, thermal expansion coefficients, heat capacity and thermal conductivity for the CexTh1-xO2 solid solution all agree well with available experimental data. The thermal expansion coefficient for ThO2 increases with CeO2 substitution, and complete substitution shows the highest expansion coefficient. On the other hand, the mixed CexTh1-xO2 (0thermodynamic properties of the CexTh1-xO2 solid solution.

  14. First-principles study of the elastic and thermodynamic properties of CaSiO3 perovskite

    NASA Astrophysics Data System (ADS)

    Liu, Z. J.; Sun, X. W.; Chen, Q. F.; Cai, L. C.; Wu, H. Y.; Ge, S. H.

    2007-06-01

    The thermodynamic and elastic properties of CaSiO3 perovskite are investigated at high pressures and temperatures using the plane wave pseudopotential method within the local density approximation. The athermal elastic moduli of CaSiO3 perovskite are calculated as a function of pressure up to 200 GPa. The calculated results are in excellent agreement with available experimental data at high pressure, and compare favourably with other pseudopotential predictions over the pressure regime studied. It is also found that the elastic anisotropy drops rapidly with the increase of pressure initially, and then decreases more slowly at higher pressures. The thermodynamic properties of CaSiO3 perovskite are predicted using the quasi-harmonic Debye model for the first time; the heat capacity and the thermal expansion coefficient agree with the observed values at ambient conditions and the other calculations at high pressures and temperatures.

  15. First-principles study of the elastic and thermodynamic properties of CaSiO(3) perovskite.

    PubMed

    Liu, Z J; Sun, X W; Chen, Q F; Cai, L C; Wu, H Y; Ge, S H

    2007-06-20

    The thermodynamic and elastic properties of CaSiO(3) perovskite are investigated at high pressures and temperatures using the plane wave pseudopotential method within the local density approximation. The athermal elastic moduli of CaSiO(3) perovskite are calculated as a function of pressure up to 200 GPa. The calculated results are in excellent agreement with available experimental data at high pressure, and compare favourably with other pseudopotential predictions over the pressure regime studied. It is also found that the elastic anisotropy drops rapidly with the increase of pressure initially, and then decreases more slowly at higher pressures. The thermodynamic properties of CaSiO(3) perovskite are predicted using the quasi-harmonic Debye model for the first time; the heat capacity and the thermal expansion coefficient agree with the observed values at ambient conditions and the other calculations at high pressures and temperatures. PMID:21694039

  16. How does confinement in nano-scale pores change the thermodynamic properties and the nature of phase transitions of water?

    E-print Network

    P. O. Fedichev; L. I. Menshikov

    2012-06-15

    We analyze thermodynamics of water samples confined in nanopores and prove that although the freezing temperature can be dramatically lower, the suppression of the ice nucleation leading to the freezing temperature depression is a truly macroscopic effect rather than a consequence of microscopic interactions. The freezing transition itself is a truly collective phenomenon described by a macroscopic order parameter (the nearly homogeneous density of the liquid within the pore away from the pores wall) exactly in the same way as in the bulk liquid. The thermodynamics properties of the confined and the bulk liquid can be described by macroscopic thermodynamics and be readily related to each other simply by proper inclusion of the additional Laplace pressure exerted by the solid-liquid boundary.

  17. Polylogarithmic representation of radiative and thermodynamic properties of thermal radiation in a given spectral range: II. Real-body radiation

    E-print Network

    Fisenko, Anatoliy I

    2015-01-01

    The general analytical expressions for the thermal radiative and thermodynamic properties of a real-body are obtained in a finite range of frequencies at different temperatures. The frequency dependence of the spectral emissivity is represented as a power series. The Stefan-Boltzmann law, total energy density, number density of photons, Helmholtz free energy density, internal energy density, enthalpy density, entropy density, heat capacity at constant volume, pressure, and total emissivity are expressed in terms of the polylogarithm functions. The general expressions for the thermal radiative and thermodynamic functions are applied for the study of thermal radiation of liquid and solid zirconium carbide. These functions are calculated using experimental data for the frequency dependence of the normal spectral emissivity in the visible-near infrared range at the melting (freezing) point. The gaps between the thermal radiative and thermodynamic functions of liquid and solid zirconium carbide are observed. The g...

  18. Thermodynamic and transport combustion properties of hydrocarbons with air. Part 2: Compositions corresponding to Kelvin temperature schedules in part 1

    NASA Technical Reports Server (NTRS)

    Gordon, S.

    1982-01-01

    The equilibrium compositions that correspond to the thermodynamic and transport combustion properties for a wide range of conditions for the reaction of hydrocarbons with air are presented. Initially 55 gaseous species and 3 coin condensed species were considered in the calculations. Only 17 of these 55 gaseous species had equilibrium mole fractions greater than 0.000005 for any of the conditions studied and therefore these were the only ones retained in the final tables.

  19. Thermodynamic properties and transport coefficients of air thermal plasmas mixed with ablated vapors of Cu and polytetrafluoroethylene

    NASA Astrophysics Data System (ADS)

    Zhang, JunMin; Lu, ChunRong; Guan, YongGang; Liu, WeiDong

    2015-10-01

    Because the fault arc in aircraft electrical system often causes a fire, it is particularly important to analyze its energy and transfer for aircraft safety. The calculation of arc energy requires the basic parameters of the arc. This paper is mainly devoted to the calculations of equilibrium composition, thermodynamic properties (density, molar weight, enthalpy, and specific heat at constant pressure) and transport coefficients (thermal conductivity, electrical conductivity, and viscosity) of plasmas produced by a mixture of air, Cu, and polytetrafluoroethylene under the condition of local thermodynamic equilibrium. The equilibrium composition is determined by solving a system of equations around the number densities of each species. The thermodynamic properties are obtained according to the standard thermodynamic relationships. The transport coefficients are calculated using the Chapman-Enskog approximations. Results are presented in the temperature range from 3000 to 30 000 K for pressures of 0.08 and 0.1 MPa, respectively. The results are more accurate and are reliable reference data for theoretical analysis and computational simulation of the behavior of fault arc.

  20. EFFECT OF HEATING RATE ON THE THERMODYNAMIC PROPERTIES OF PULVERIZED COAL

    SciTech Connect

    Ramanathan Sampath

    2000-01-01

    This final technical report describes work performed under DOE Grant No. DE-FG22-96PC96224 during the period September 24, 1996 to September 23, 1999 which covers the entire performance period of the project. During this period, modification, alignment, and calibration of the measurement system, measurement of devolatilization time-scales for single coal particles subjected to a range of heating rates and temperature data at these time-scales, and analysis of the temperature data to understand the effect of heating rates on coal thermal properties were carried out. A new thermodynamic model was developed to predict the heat transfer behavior for single coal particles using one approach based on the analogy for thermal property of polymers. Results of this model suggest that bituminous coal particles behave like polymers during rapid heating on the order of 10{sup 4}-10{sup 5} K/s. At these heating rates during the early stages of heating, the vibrational part of the heat capacity of the coal molecules appears to be still frozen but during the transition from heat-up to devolatilization, the heat capacity appears to attain a sudden jump in its value as in the case of polymers. There are a few data available in the coal literature for low heating rate experiments (10{sup 2}-10{sup 3} K/s) conducted by UTRC, our industrial partner, in this project. These data were obtained for a longer heating duration on the order of several seconds as opposed to the 10 milliseconds heating time of the single particle experiments discussed above. The polymer analogy model was modified to include longer heating time on the order of several seconds to test these data. However, the model failed to predict these low heating rate data. It should be noted that UTRC's work showed reasonably good agreement with Merrick model heat capacity predictions at these low heating rates, but at higher heating rates UTRC observed that coal thermal response was heat flux dependent. It is concluded that at combustion level heating rates (10{sup 4}-10{sup 5} K/s) coal structural changes are delayed and attendant increases in heat capacity and thermal conductivity are pushed to higher temperatures or require significant hold times to become manifest.

  1. Estimation of the thermodynamic properties of functional groups and biomolecules using quantum chemical/statistical thermodynamic calculations

    NASA Astrophysics Data System (ADS)

    Chai, Weisin

    The scarcity and sustainability of energy sources have always been a concern while seeking for alternative fuels. Biofuels have drawn the attention of various researchers due to their abundancy and renewability. Understanding the physical and chemical properties of these molecules is essential to determining their potential as alternative fuels or fuel additives. In this work, the properties of these molecules are predicted through methods developed from quantum mechanics and statistical mechanics theories. The heats of formations are calculated with the Gaussian program and combined with the Benson group contribution method to predict the Benson parameters of unknown functional groups in a molecule. The methods developed are used to expand the Benson database and improve the practicability of the group contribution method. The heats of formations are also used to predict and correlate heat capacities across a range of temperatures and energy densities in this study.

  2. Thermodynamic properties for rare earths and americium in pyropartitioning process solvents

    SciTech Connect

    Fusselman, S.P.; Roy, J.J.; Grimmett, D.L.

    1999-07-01

    The design of a molten metal-molten salt based chemical and electrochemical process for separation of actinides from plutonium-uranium extraction waste requires a consistent set of thermodynamic properties for the actinides and rare earths present in nuclear waste. Standard potential data for Y, La, Ce, Pr, and Gd in molten LiCl-KCl were obtained. Americium data obtained were standard potentials in molten LiCl-KCl and activity coefficients for Cd and Bi. Data were obtained between 400 and 500 C. Results for the rare earth chlorides using an improved experimental technique were consistent with theory, with standard free energy of formation values somewhat more negative than those found in the literature. Special attention was given to Am in the LiCl-KCl/Cd system because it can exist as the +2 and/or +3 ion in this system. Americium ions existed only as the +3 ion in LiCl-KCl/Bi. Standard electrochemical potentials for Am/Am{sup +2} in LiCl-KCl eutectic at 400, 450, and 500 C were {minus}2.893, {minus}2.853, and {minus}2.838 V, respectively, relative to Cl{sup 2}/Cl{sup {minus}}. Standard electrochemical potentials vs. Cl{sub 2}/Cl{sup {minus}} for Am/Am{sup +3} in LiCl-KCl eutectic were {minus}2.83 V at 450 C and {minus}2.78 V at 500 C. Activity coefficients for Am in molten Cd were 1 {times} 10{sup {minus}5} and 8 {times} 10{sup {minus}5} at 450 and 500 C.

  3. Thermodynamic properties of calcium-bismuth alloys determined by emf measurements

    SciTech Connect

    Kim, H; Boysen, DA; Bradwell, DJ; Chung, BC; Jiang, K; Tomaszowska, AA; Wang, KL; Wei, WF; Sadoway, DR

    2012-01-15

    The thermodynamic properties of Ca-Bi alloys were determined by electromotive force (emf) measurements to assess the suitability of Ca-Bi electrodes for electrochemical energy storage applications. Emf was measured at ambient pressure as a function of temperature between 723 K and 1173 K using a Ca(s)vertical bar CaF2(s)vertical bar Ca(in Bi) cell for twenty different Ca-Bi alloys spanning the entire range of composition from chi(Ca) = 0 to 1. Reported are the temperature-independent partial molar entropy and enthalpy of calcium for each Ca-Bi alloy. Also given are the measured activities of calcium, the excess partial molar Gibbs energy of bismuth estimated from the Gibbs-Duhem equation, and the integral change in Gibbs energy for each Ca-Bi alloy at 873 K, 973 K, and 1073 K. Calcium activities at 973 K were found to be nearly constant at a value a(Ca) = 1 x 10(-8) over the composition range chi(Ca) = 0.32-0.56, yielding an emf of similar to 0.77 V. Above chi(Ca) = 0.62 and coincident with Ca5Bi3 formation, the calcium activity approached unity. The Ca-Bi system was also characterized by differential scanning calorimetry over the entire range of composition. Based upon these data along with the emf measurements, a revised Ca-Bi binary phase diagram is proposed. (C) 2011 Elsevier Ltd. All rights reserved.

  4. Thermodynamic stability, kinetic inertness and relaxometric properties of monoamide derivatives of lanthanide(III) DOTA complexes.

    PubMed

    Tei, Lorenzo; Baranyai, Zsolt; Gaino, Luca; Forgács, Attila; Vágner, Adrienn; Botta, Mauro

    2015-03-28

    A complete thermodynamic and kinetic solution study on lanthanide(III) complexes with monoacetamide (DOTAMA, L1) and monopropionamide (DOTAMAP, L2) derivatives of DOTA (DOTA = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) was undertaken with the aim to elucidate their stability and inertness in aqueous media. The stability constants of GdL1 and GdL2 are comparable, whereas a more marked difference is found in the kinetic inertness of the two complexes. The formation of the Eu(III) and Ce(III) complexes takes place via the formation of the protonated intermediates which can deprotonate and transform into the final complex through a OH(-) assisted pathway. GdL2 shows faster rates of acid catalysed decomplexation with respect to GdL1, which has a kinetic inertness comparable to GdDOTA. Nevertheless, GdL2 is one order of magnitude more inert than GdDO3A. A novel DOTAMAP-based bifunctional chelating ligand and its deoxycholic acid derivative (L5) were also synthesized. Since the coordinated water molecule in GdL2 is characterized by an exchange rate ca. two orders of magnitude greater than in GdL1, the relaxivity of the macromolecular derivatives of L5 should not be limited by the slow water exchange process. The relaxometric properties of the supramolecular adduct of GdL5 with human serum albumin (HSA) were investigated in aqueous solution by measuring the magnetic field dependence of the (1)H relaxivity which, at 20 MHz and 298 K, shows a 430% increase over that of the unbound GdL5 chelate. Thus, Gd(III) complexes with DOTAMAP macrocyclic ligands can represent good candidates for the development of stable and highly effective bioconjugate systems for molecular imaging applications. PMID:25695351

  5. Thermodynamic and mechanical properties of copper precipitates in ?-iron from atomistic simulations

    NASA Astrophysics Data System (ADS)

    Erhart, Paul; Marian, Jaime; Sadigh, Babak

    2013-07-01

    Precipitate hardening is commonly used in materials science to control strength by acting on the number density, size distribution, and shape of solute precipitates in the hardened matrix. The Fe-Cu system has attracted much attention over the last several decades due to its technological importance as a model alloy for Cu steels. In spite of these efforts several aspects of its phase diagram remain unexplained. Here we use atomistic simulations to characterize the polymorphic phase diagram of Cu precipitates in body-centered cubic (BCC) Fe and establish a consistent link between their thermodynamic and mechanical properties in terms of thermal stability, shape, and strength. The size at which Cu precipitates transform from BCC to a close-packed 9R structure is found to be strongly temperature dependent, ranging from approximately 4 nm in diameter (˜2700atoms) at 200 K to about 8 nm (˜22800atoms) at 700 K. These numbers are in very good agreement with the interpretation of experimental data given Monzen [Philos. Mag. APMAADG0141-861010.1080/01418610008212077 80, 711 (2000)]. The strong temperature dependence originates from the entropic stabilization of BCC Cu, which is mechanically unstable as a bulk phase. While at high temperatures the transition exhibits first-order characteristics, the hysteresis, and thus the nucleation barrier, vanish at temperatures below approximately 300 K. This behavior is explained in terms of the mutual cancellation of the energy differences between core and shell (wetting layer) regions of BCC and 9R nanoprecipitates, respectively. The proposed mechanism is not specific for the Fe-Cu system but could generally be observed in immiscible systems, whenever the minority component is unstable in the lattice structure of the host matrix. Finally, we also study the interaction of precipitates with screw dislocations as a function of both structure and orientation. The results provide a coherent picture of precipitate strength that unifies previous calculations and experimental observations.

  6. Thermodynamic and transport properties of self-assembled monolayers from molecular simulations 

    E-print Network

    Aydogmus, Turkan

    2006-04-12

    at the same separations decreases. The third application focus is on the use of SAMs for tailoring surface and structural properties of OMMs, in particular, porous silicas. A molecular study of structural and surface properties of a silica material with a 5...

  7. Structural, Thermodynamic, Elastic, and Electronic Properties of ?-SnS at High Pressure from First-Principles Investigations

    NASA Astrophysics Data System (ADS)

    Liu, Chun Mei; Xu, Chao; Duan, Man Yi

    2015-10-01

    SnS has potential technical applications, but many of its properties are still not well studied. In this work, the structural, thermodynamic, elastic, and electronic properties of ?-SnS have been investigated by the plane wave pseudo-potential density functional theory with the framework of generalised gradient approximation. The calculated pressure-dependent lattice parameters agree well with the available experimental data. Our thermodynamic properties of ?-SnS, including heat capacity CP , entropy S, and Gibbs free energy relation of -(GT -H0) curves, show similar growth trends as the experimental data. At T=298.15 K, our CP =52.31 J/mol·K, S=78.93 J/mol·K, and -(GT -H0)=12.03 J/mol all agree very well with experimental data CP =48.77 J/mol·K and 49.25 J/mol·K, S=76.78 J/mol·K, and -(GT -H0)=12.38 J/mol. The elastic constants, together with other elastic properties, are also computed. The anisotropy analyses indicate obvious elastic anisotropy for ?-SnS along different symmetry planes and axes. Moreover, calculations demonstrate that ?-SnS is an indirect gap semiconductor, and it transforms to semimetal with pressure increasing up to 10.2 GPa. Combined with the density of states, the characters of the band structure have been analysed in detail.

  8. The general AMBER force field (GAFF) can accurately predict thermodynamic and transport properties of many ionic liquids.

    PubMed

    Sprenger, K G; Jaeger, Vance W; Pfaendtner, Jim

    2015-05-01

    We have applied molecular dynamics to calculate thermodynamic and transport properties of a set of 19 room-temperature ionic liquids. Since accurately simulating the thermophysical properties of solvents strongly depends upon the force field of choice, we tested the accuracy of the general AMBER force field, without refinement, for the case of ionic liquids. Electrostatic point charges were developed using ab initio calculations and a charge scaling factor of 0.8 to more accurately predict dynamic properties. The density, heat capacity, molar enthalpy of vaporization, self-diffusivity, and shear viscosity of the ionic liquids were computed and compared to experimentally available data, and good agreement across a wide range of cation and anion types was observed. Results show that, for a wide range of ionic liquids, the general AMBER force field, with no tuning of parameters, can reproduce a variety of thermodynamic and transport properties with similar accuracy to that of other published, often IL-specific, force fields. PMID:25853313

  9. First-principles calculations of structural, electronic, and thermodynamic properties of ZnO1-xSx alloys

    NASA Astrophysics Data System (ADS)

    Muhammad, Zafar; Shabbir, Ahmed; Shakil, M.; A. Choudhary, M.

    2014-10-01

    In this study the pseudo-potential method is used to investigate the structural, electronic, and thermodynamic properties of ZnO1-xSx semiconductor materials. The results show that the electronic properties are found to be improved when calculated by using LDA + U functional as compared with local density approximation (LDA). At various concentrations the ground-state properties are determined for bulk materials ZnO, ZnS, and their tertiary alloys in cubic zinc-blende phase. From the results, a minor difference is observed between the lattice parameters from Vegard's law and other calculated results, which may be due to the large mismatch between lattice parameters of binary compounds ZnO and ZnS. A small deviation in the bulk modulus from linear concentration dependence is also observed for each of these alloys. The thermodynamic properties, including the phonon contribution to Helmholtz free energy ?F, phonon contribution to internal energy ?E, and specific heat at constant-volume CV, are calculated within quasi-harmonic approximation based on the calculated phonon dispersion relations.

  10. Thermodynamic properties and transport coefficients of high-temperature CO2 thermal plasmas mixed with C2F4

    NASA Astrophysics Data System (ADS)

    Yang, Aijun; Liu, Yang; Sun, Bowen; Wang, Xiaohua; Cressault, Yann; Zhong, Linlin; Rong, Mingzhe; Wu, Yi; Niu, Chunping

    2015-12-01

    This paper is devoted to the calculation of fundamental properties of CO2 mixed with C2F4. The species composition and thermodynamic properties (mass density, entropy, enthalpy and specific heat at constant pressure) are based on Gibbs free energy minimization. The transport properties (electrical conductivity, viscosity and thermal conductivity) are calculated by the well-known Chapman-Enskog method. The Lennard-Jones like phenomenological potential and some recently updated transport cross sections are adopted to obtain collision integrals. The calculation is developed in the temperature range between 300 and 30?000?K, for a pressure between 1 to 16 bar and for several C2F4 proportions. Transport coefficients for CO2 are also compared with previous published values, and the reasons for discrepancies are analyzed. The results obtained for CO2–C2F4 mixtures provide reliable reference data for the simulation of switching arcs in CO2 circuit breakers with the ablation of PTFE.

  11. On the radiative and thermodynamic properties of the cosmic radiations using COBE FIRAS instrument data: I. Cosmic microwave background radiation

    NASA Astrophysics Data System (ADS)

    Fisenko, Anatoliy I.; Lemberg, Vladimir

    2014-07-01

    Using the explicit form of the functions to describe the monopole and dipole spectra of the Cosmic Microwave Background (CMB) radiation, the exact expressions for the temperature dependences of the radiative and thermodynamic functions, such as the total radiation power per unit area, total energy density, number density of photons, Helmholtz free energy density, entropy density, heat capacity at constant volume, and pressure in the finite range of frequencies v 1? v? v 2 are obtained. Since the dependence of temperature upon the redshift z is known, the obtained expressions can be simply presented in z representation. Utilizing experimental data for the monopole and dipole spectra measured by the COBE FIRAS instrument in the 60-600 GHz frequency interval at the temperature T=2.72548 K, the values of the radiative and thermodynamic functions, as well as the radiation density constant a and the Stefan-Boltzmann constant ? are calculated. In the case of the dipole spectrum, the constants a and ?, and the radiative and thermodynamic properties of the CMB radiation are obtained using the mean amplitude T amp=3.358 mK. It is shown that the Doppler shift leads to a renormalization of the radiation density constant a, the Stefan-Boltzmann constant ?, and the corresponding constants for the thermodynamic functions. The expressions for new astrophysical parameters, such as the entropy density/Boltzmann constant, and number density of CMB photons are obtained. The radiative and thermodynamic properties of the Cosmic Microwave Background radiation for the monopole and dipole spectra at redshift z?1089 are calculated.

  12. Revised thermodynamic properties of brucite determined by solubility studies and its significance to nuclear waste isolation.

    SciTech Connect

    Xiong, Yongliang

    2007-05-01

    MgO is the only engineered barrier certified by EPA for the Waste Isolation Pilot Plant (WIPP) in USA. The German Asse repository will also employ an Mg(OH){sub 2} (brucite)-based engineered barrier. The chemical function of the engineered barrier is to consume CO{sub 2} that may be generated by the microbial degradation of organic materials in waste packages. Experimental results at SNL indicate that MgO is first hydrated as brucite, and then brucite is carbonated as hydromagnesite (5424) (Mg{sub 5}(CO{sub 3}){sub 4}(OH){sub 2} {center_dot} 4H{sub 2}O). As MgO is in excess relative to CO{sub 2} that may be produced, the brucite-hydromagnesite (5424) assemblage would buffer f{sub CO2} in the repository. Consequently, the thermodynamic properties of this assemblage is of great significance to the performance assessment (PA) as actinide solubility is strongly affected by f{sub CO2}. In turn, PA is important to the demonstration of the long-term safety of nuclear waste repositories, as assessed by the use of probabilistic performance calculations. There is a substantial discrepancy for {Delta}{sub f}G{sub brucite}{sup 0} in recent publications, ranging from -830.4 (Harvie et al., 1984; Geochim. Cosmochim. Acta, 723-751), through -831.9 (Brown et al., 1996; J. Chem. Soc., Dalton Trans., 3071-3075), through -833.5 (Robie and Hemingway, 1995; USGS Bull., 2131), and to -835.9 kJ mol{sup -1} (Konigsberger et al., 1999; Geochim. Cosmochim. Acta, 3105-3119). Using the {Delta}{sub f}G{sub hydromagnesite (5424)}{sup 0} from Konigsberger et al., the predicted log f{sub CO2} for this assemblage would range from -5.96 ({Delta}{sub f}G{sub brucite}{sup 0} from Harvie et al.) to -4.84 ({Delta}{sub f}G{sub brucite}{sup 0} from Konigsberger et al.). Therefore, it is desirable to better constrain the {Delta}{sub f}G{sub brucite}{sup 0}. For this reason, a series of solubility experiments involving brucite in NaCl solutions ranging from 0.01 M to 4.0 M have being conducted at SNL. The derived {Delta}{sub f}G{sub brucite}{sup 0} from this study by extrapolation to infinite dilution via Pitzer formalism is -830.8 kJ mol{sup -1}, which is in excellent agreement with recommended values of Harvie et al. and Brown et al.

  13. Thermodynamic Properties of Atmospheric Instability Associated With The Generation of Local Thunderstorms In Atmospheric Local Circulation

    NASA Astrophysics Data System (ADS)

    Nishiyama, K.; Jinno, K.; Kawamura, A.; Wakimizu, K.

    During a summer season after a rainy season in Japan, local thunderstorms occur in- land in the afternoon due to sun radiation and the subsequent development of local circulation including sea breeze or valley wind under the influence of the Pacific high pressure system. Some of the thunderstorms develop due to strong atmospheric in- stability and cause heavy precipitation and the resultant local flood. In our previous study, the observation of thunderstorms has been carried out using the meteorological radar and satellite images and, the Automated Meteorological Data Acquisition Sys- tem (AMeDAS), which is the ground observational network of the Japan Meteorolog- ical Agency, in the Northern Kyushu located in the west of Japan islands. AMeDAS consists of four elements, which are wind velocity and direction, temperature, rain- fall, duration of sunshine. Since AMeDAS has the fine resolution of approximately 20 km by 20 km and records these data every 10 minutes, it can be a useful tool for detecting the generation of local thunderstorms. These observations showed that tem- perature near the ground increased due to sun radiation and the subsequent sea breeze penetration towards inland formed convergence zone before the generation of local thunderstorms. It is inferred that the development of the atmospheric instability in the convergence zone around the sea breeze front was closely associated with the gen- eration of the local thunderstorms. This means that sea breeze circulation can trans- form atmospheric instability in the morning into more unstable situation. Therefore, it should be noted that the development of atmospheric instability with the movement and strength of sea breeze circulation is important factor for the generation of thun- derstorms. In this study, thermodynamic properties of atmospheric instability in a sea breeze circulation were investigated using a two-dimensional numerical model. Con- sequently, it could be confirmed that the increase of temperature and water vapor in a sea breeze front led to the drastic lowering of LFC (Level of Free Convection) as an index of trigger of thunderstorm generation and the corresponding increase of CAPE (Convective Available Potential Energy), which represents the strength of convective 1 activity of a generated thunderstorm. This means that the increase of temperature and water vapor contributes to the drastic increase of atmospheric instability through the activity of atmospheric local circulation and the resultant thunderstorms form locally. 2

  14. Thermodynamic Properties of Actinide-Zirconium Dioxide Solid-Solutions Relevant for Advanced Nuclear Fuels

    SciTech Connect

    Shuller, L.C.; Ewing, R.C.; Pavenayotin, N.; Ewing, R.C.; Skomurski, F.N.; Ewing, R.C.; Becker, U.

    2008-07-01

    Currently, spent nuclear fuel (SNF) from commercial reactors is composed of 95-99% UO{sub 2} and 1-5% fission products and transuranium elements. Thus, the primary waste form is the UO{sub 2} matrix, which over time will corrode to a variety of U(VI)-secondary phases. Alternative nuclear fuels, such as inert-matrix fuels and mixed-oxide fuels, have been studied for their in-reactor performance; however little research has been conducted to understand the behavior of these fuels as a wasteform. We use density functional theory and Monte-Carlo methods to understand the solid solution behavior of (Ac, Zr)O{sub 2} (Ac = Th, U, Np, Pu) phases. The end members of interest include ZrO{sub 2}, ThO{sub 2}, UO{sub 2}, NpO{sub 2}, and PuO{sub 2}, and all share the cubic-fluorite structure. The excess enthalpy of mixing ({delta}H{sub excess}), excess Gibbs free energy of mixing ({delta}G{sub excess}), and excess configurational entropy ({delta}S{sub excess}) are calculated for the above solid solution series, and from {delta}G{sub excess}, miscibility gaps are identified. In conclusion: Density functional theory and Monte Carlo simulations were used in this study to determine the thermodynamic properties of binary oxide solid solutions that are useful for advanced nuclear fuel applications. The DFT results for each solid solution series is of the single cubic unit cell; therefore, only one interaction parameter was calculated. Based on the Monte-Carlo results, on the order of 25% Zr can be incorporated into the AcO{sub 2} structures (Ac = Th, U, Np, or Pu). However, only trace amounts of the actinides can be incorporated into ZrO{sub 2}. Considering larger systems in the DFT calculations will improve results, because more cation-cation interaction parameters can be calculated. Configurational ordering can also be considered with larger systems. Molecular dynamic simulations will be used to determine the temperature dependence of the different solid solutions that is more specific to their respective lattice dynamics. (authors)

  15. A Density Functional Investigation of the Structural, Elastic and Thermodynamic Properties of the Au-Sn Intermetallics

    NASA Astrophysics Data System (ADS)

    Tian, Yali; Zhou, Wei; Wu, Ping

    2015-11-01

    The structural, elastic and thermodynamic properties of AuSn, AuSn2, AuSn4 and Au5Sn are investigated by first-principles calculations. Through calculation, the four intermetallic compounds are all thermodynamically stable and AuSn has the largest negative formation energy. They are all ductile, anisotropic and have low stiffness. In addition, Au5Sn is different from the others, since it is elastically unstable and possesses the highest anisotropy and hardness, mainly due to the strong Au-Au covalent bonds. Based on the quasi-harmonic Debye model, the thermodynamic properties of AuSn, such as the volume, thermal expansion coefficient, bulk modulus, Debye temperature and heat capacity with temperature variation in the range of 0-20 GPa, are obtained. The results indicate the increments of both the volume and thermal expansion coefficient with temperature become slow when the pressure is more than 10 GPa, and the bulk modulus and Debye temperature are almost constant below 100 K and then become linear decreasing as temperature increases. It is found that the influence of temperature on heat capacity is much more obvious than that of pressure.

  16. Fluids confined in wedges and by edges: Virial series for the line-thermodynamic properties of hard spheres

    SciTech Connect

    Urrutia, Ignacio

    2014-12-28

    This work is devoted to analyze the relation between the thermodynamic properties of a confined fluid and the shape of its confining vessel. Recently, new insights in this topic were found through the study of cluster integrals for inhomogeneous fluids that revealed the dependence on the vessel shape of the low density behavior of the system. Here, the statistical mechanics and thermodynamics of fluids confined in wedges or by edges is revisited, focusing on their cluster integrals. In particular, the well known hard sphere fluid, which was not studied in this framework so far, is analyzed under confinement and its thermodynamic properties are analytically studied up to order two in the density. Furthermore, the analysis is extended to the confinement produced by a corrugated wall. These results rely on the obtained analytic expression for the second cluster integral of the confined hard sphere system as a function of the opening dihedral angle 0 < ? < 2?. It enables a unified approach to both wedges and edges.

  17. Thermodynamic properties of supercritical n-m Lennard-Jones fluids and isochoric and isobaric heat capacity maxima and minima.

    PubMed

    Mairhofer, Jonas; Sadus, Richard J

    2013-10-21

    Molecular dynamics simulations are reported for the thermodynamic properties of n-m Lennard-Jones fluids, where n = 10 and 12, and m = 5 and 6. Results are reported for the thermal expansion coefficient, isothermal and adiabatic compressibilities, isobaric and isochoric heat capacities, Joule-Thomson coefficient, and speed of sound at supercritical conditions covering a wide range of fluid densities. The thermodynamic criteria for maxima?minima in the isochoric and isobaric heat capacities are identified and the simulation results are also compared with calculations from Lennard-Jones equations of state. The Johnson et al. [Mol. Phys. 78, 591 (1993)] equation of state can be used to reproduce all heat capacity phenomena reported [T. M. Yigzawe and R. J. Sadus, J. Chem. Phys. 138, 194502 (2013)] from molecular dynamics simulations for the 12-6 Lennard-Jones potential. Significantly, these calculations and molecular dynamics results for other n-m Lennard-Jones potentials support the existence of Cp minima at supercritical conditions. The values of n and m also have a significant influence on many other thermodynamic properties. PMID:24160523

  18. The IAPWS Formulation 1995 for the Thermodynamic Properties of Ordinary Water Substance for General and Scientific Use

    NASA Astrophysics Data System (ADS)

    Wagner, Wolfgang; Pruß, Andreas

    2002-06-01

    In 1995, the International Association for the Properties of Water and Steam (IAPWS) adopted a new formulation called "The IAPWS Formulation 1995 for the Thermodynamic Properties of Ordinary Water Substance for General and Scientific Use", which we abbreviate to IAPWS-95 formulation or IAPWS-95 for short. This IAPWS-95 formulation replaces the previous formulation adopted in 1984. This work provides information on the selected experimental data of the thermodynamic properties of water used to develop the new formulation, but information is also given on newer data. The article presents all details of the IAPWS-95 formulation, which is in the form of a fundamental equation explicit in the Helmholtz free energy. The function for the residual part of the Helmholtz free energy was fitted to selected data for the following properties: (a) thermal properties of the single-phase region (p?T) and of the vapor-liquid phase boundary (p??'??T), including the phase-equilibrium condition (Maxwell criterion), and (b) the caloric properties specific isochoric heat capacity, specific isobaric heat capacity, speed of sound, differences in the specific enthalpy and in the specific internal energy, Joule-Thomson coefficient, and isothermal throttling coefficient. By applying modern strategies for optimizing the functional form of the equation of state and for the simultaneous nonlinear fitting to the data of all mentioned properties, the resulting IAPWS-95 formulation covers a validity range for temperatures from the melting line (lowest temperature 251.2 K at 209.9 MPa) to 1273 K and pressures up to 1000 MPa. In this entire range of validity, IAPWS-95 represents even the most accurate data to within their experimental uncertainty. In the most important part of the liquid region, the estimated uncertainty of IAPWS-95 ranges from ±0.001% to ±0.02% in density, ±0.03% to ±0.2% in speed of sound, and ±0.1% in isobaric heat capacity. In the liquid region at ambient pressure, IAPWS-95 is extremely accurate in density (uncertainty ?±0.0001%) and in speed of sound (±0.005%). In a large part of the gas region the estimated uncertainty in density ranges from ±0.03% to ±0.05%, in speed of sound it amounts to ±0.15% and in isobaric heat capacity it is ±0.2%. In the critical region, IAPWS-95 represents not only the thermal properties very well but also the caloric properties in a reasonable way. Special interest has been focused on the extrapolation behavior of the new formulation. At least for the basic properties such as pressure and enthalpy, IAPWS-95 can be extrapolated up to extremely high pressures and temperatures. In addition to the IAPWS-95 formulation, independent equations for vapor pressure, the densities, and the most important caloric properties along the vapor-liquid phase boundary, and for the pressure on the melting and sublimation curve, are given. Moreover, a so-called gas equation for densities up to 55 kg m-3 is also included. Tables of the thermodynamic properties calculated from the IAPWS-95 formulation are listed in the Appendix.

  19. a Molecular Approach to Electrolyte Solutions: Predicting Phase Behavior and Thermodynamic Properties of Single and Binary-Solvent Systems

    NASA Astrophysics Data System (ADS)

    Gering, Kevin Leslie

    A molecular formulation based on modern liquid state theory is applied to the properties and phase behavior of electrolyte systems containing volatile species. An electrolyte model based on the exponential modification of the Mean Spherical Approximation (EXP-MSA) is used to describe the cation-cation, cation-anion, and anion-anion distributions of the ionic species. This theory represents an improvement over the nonmodified MSA approach, and goes beyond the usual Debye-Huckel theory and Pitzer correlation for treating concentrated solutions. Electrolyte solutions such as water-salt, ammonia-salt, mixed salts, and mixed -solvent systems are investigated over a wide range of temperatures, pressures, and compositions. The usual salt properties, such as osmotic and mean activity coefficients and other thermodynamic properties (enthalpies), are calculated. The predictions are accurate to saturation limits. In addition, an iterative method is presented that is used to predict vapor-liquid equilibria (VLE) and thermodynamic properties of single-salt multisolvent electrolytes of the form solvent-cosolvent-salt. In this method, a local composition model (LCM) and EXP-MSA theory are combined with traditional phase equilibria relations to estimate the pressures and compositions of a vapor phase in equilibrium with a binary-solvent electrolyte. Also, a pseudo-solvent model is proposed as a means of obtaining a variety of averaged liquid phase electrolyte properties. To predict preferential solvation in mixed solvents, a general framework is developed that is based on predicted solvation numbers of each solvent. Preferential solvation will be shown to influence VLE. Results show that phase equilibria is accurately predicted by the above iterative method. Three mixed-solvent electrolyte systems are investigated: water -ethylene glycol-LiBr, ammonia-water-LiBr, and methanol -water-LiCl. Finally, the above electrolyte model is utilized in predicting design criteria for a single-effect absorption cooling cycle.

  20. First-principles investigations on the elastic and thermodynamic properties of cubic ZrO2 under high pressure

    NASA Astrophysics Data System (ADS)

    Wei, Ning; Zhang, Xiaoli; Zhang, Chuanguo; Hou, Songjun; Zeng, Z.

    2015-10-01

    We have investigated the elastic and thermodynamic properties of ZrO2 under pressure up to 120 Gpa by the plane wave pseudopotential density functional theory with the generalized gradient approximation (GGA) method. The elastic constants of ZrO2 are calculated and meet the generalized stability criteria, suggesting that ZrO2 is mechanically stable within this pressure range. The pressure effects on the elastic properties reveal that the elastic modulus B, shear modulus G and Young's modulus Y increase linearly with the pressure increasing, implying that the resistance to deformation is enhanced. In addition, by analyzing the Poisson's ratio ? and the value of B/G, we notice that ZrO2 is regarded as being a ductile material under high pressure and the ductility can be improved by the pressure increasing. Then, we employ the quasi-harmonic Debye model considering the phononic effects to obtain the thermodynamic properties of ZrO2. Debye temperature ?D, thermal expansion coefficient ?, heat capacity Cp and Grüneisen parameter ? are systematically explored at pressure of 0-80 Gpa and temperature of 0-1000 K. Our results have provided fundamental facts and evidences for further experimental and theoretical researches.

  1. An analysis of quantum effects on the thermodynamic properties of cryogenic hydrogen using the path integral method

    SciTech Connect

    Nagashima, H.; Tsuda, S.; Tsuboi, N.; Koshi, M.; Hayashi, K. A.; Tokumasu, T.

    2014-04-07

    In this paper, we describe the analysis of the thermodynamic properties of cryogenic hydrogen using classical molecular dynamics (MD) and path integral MD (PIMD) method to understand the effects of the quantum nature of hydrogen molecules. We performed constant NVE MD simulations across a wide density–temperature region to establish an equation of state (EOS). Moreover, the quantum effect on the difference of molecular mechanism of pressure–volume–temperature relationship was addressed. The EOS was derived based on the classical mechanism idea only using the MD simulation results. Simulation results were compared with each MD method and experimental data. As a result, it was confirmed that although the EOS on the basis of classical MD cannot reproduce the experimental data of saturation property of hydrogen in the high-density region, the EOS on the basis of PIMD well reproduces those thermodynamic properties of hydrogen. Moreover, it was clarified that taking quantum effects into account makes the repulsion force larger and the potential well shallower. Because of this mechanism, the intermolecular interaction of hydrogen molecules diminishes and the virial pressure increases.

  2. First-principles calculations for thermodynamic properties of type-I silicon clathrate intercalated by sodium atoms

    NASA Astrophysics Data System (ADS)

    Zhang, Wei; Chen, Qing Yun; Li, Bin; Zeng, Zhao Yi; Cai, Ling Cang

    2015-09-01

    The ground state properties of the silicon clathrate Si46 intercalated by alkali metal sodium atoms (Na8Si46) are investigated by first-principle methods. Birch-Murnaghan equation of state is fitted to two sets of the E-V data calculated by density functional theory based on the plane-wave basis set within both the local density approximation (LDA) and the generalized gradient approximation (GGA). Through quasi-harmonic Debye model, some thermodynamic properties comprise the heat capacity, the thermal expansion coefficient, Debye temperature and the Grüneisen parameter for this clathrate compounds Na8Si46 are obtained, which agree well with experimental results. Comparing the calculated heat specific in two ways with experimental results, we find that it is more accurate to describe the “rattle” modes of gust Na atoms in the cages as Einstein oscillators. Moreover, the effects of high pressure on these thermodynamic properties are also investigated which will be very helpful for a synthesis of these clathrate compounds in experiments under high pressure and high temperature condition.

  3. Anisotropy and temperature dependence of structural, thermodynamic, and elastic properties of crystalline cellulose I?: a first-principles investigation

    NASA Astrophysics Data System (ADS)

    Dri, Fernando L.; Shang, ShunLi; Hector, Louis G., Jr.; Saxe, Paul; Liu, Zi-Kui; Moon, Robert J.; Zavattieri, Pablo D.

    2014-12-01

    Anisotropy and temperature dependence of structural, thermodynamic and elastic properties of crystalline cellulose I? were computed with first-principles density functional theory (DFT) and a semi-empirical correction for van der Waals interactions. Specifically, we report the computed temperature variation (up to 500 K) of the monoclinic cellulose I? lattice parameters, constant pressure heat capacity, Cp, entropy, S, enthalpy, H, the linear thermal expansion components, ?i, and components of the isentropic and isothermal (single crystal) elastic stiffness matrices, CijS (T) and CijT (T) , respectively. Thermodynamic quantities from phonon calculations computed with DFT and the supercell method provided necessary inputs to compute the temperature dependence of cellulose I? properties via the quasi-harmonic approach. The notable exceptions were the thermal conductivity components, ?i (the prediction of which has proven to be problematic for insulators using DFT) for which the reverse, non-equilibrium molecular dynamics approach with a force field was applied. The extent to which anisotropy of Young's modulus and Poisson's ratio is temperature-dependent was explored in terms of the variations of each with respect to crystallographic directions and preferred planes containing specific bonding characteristics (as revealed quantitatively from phonon force constants for each atomic pair, and qualitatively from charge density difference contours). Comparisons of the predicted quantities with available experimental data revealed reasonable agreement up to 500 K. Computed properties were interpreted in terms of the cellulose I? structure and bonding interactions.

  4. Theoretical predictions of the structural and thermodynamic properties of MgZn2 Laves phase under high pressure

    NASA Astrophysics Data System (ADS)

    Liu, Yong; Hu, Wen-Cheng; Li, De-Jiang; Zeng, Xiao-Qin; Xu, Chun-Shui

    2014-04-01

    The structural and thermodynamic properties of MgZn2 Laves phase under hydrostatic pressure have been investigated by using a first-principles method based on the density functional theory within the generalized gradient approximation. The calculated equilibrium structural parameters are consistent with the previous experimental and theoretical data. Especially, we study the pressure dependence of the elastic constants, polycrystalline elastic moduli, Poisson's ratio, elastic anisotropy, and theoretical Vickers hardness of MgZn2. It is found that the pressure plays a significant role in the elastic properties of MgZn2 due to the variations of inter-atomic distance. In addition, the density of states and Mulliken analysis are performed to reveal the bonding characteristics of MgZn2. It is observed that the total density of states exhibits a certain offset with the increase of external pressure. Finally, the dependences of thermodynamic properties on pressure and temperature of MgZn2 Laves phase have been also successfully predicted and analyzed within the quasi-harmonic Debye model for the first time.

  5. A possible cosmological application of some thermodynamic properties of the black body radiation in $n-$dimensional Euclidean spaces

    E-print Network

    Julian Gonzalez-Ayala; J. Perez-Oregon; Rubén Cordero; F. Angulo-Brown

    2015-02-19

    In this work we present the generalization of some thermodynamic properties of the black body radiation (BBR) towards an $n-$dimensional Euclidean space. For this case the Planck function and the Stefan-Boltzmann law have already been given by Landsberg and de Vos and some adjustments by Menon and Agrawal. However, since then no much more has been done on this subject and we believe there are some relevant aspects yet to explore. In addition to the results previously found we calculate the thermodynamic potentials, the efficiency of the Carnot engine, the law for adiabatic processes and the heat capacity at constant volume. There is a region at which an interesting behavior of the thermodynamic potentials arise, maxima and minima appear for the $n-d$ BBR system at very high temperatures and low dimensionality, suggesting a possible application to cosmology. Finally we propose that an optimality criterion in a thermodynamic framework could have to do with the $3-d$ nature of the universe.

  6. A possible cosmological application of some thermodynamic properties of the black body radiation in $n-$dimensional Euclidean spaces

    E-print Network

    Gonzalez-Ayala, Julian; Cordero, Rubén; Angulo-Brown, F

    2015-01-01

    In this work we present the generalization of some thermodynamic properties of the black body radiation (BBR) towards an $n-$dimensional Euclidean space. For this case the Planck function and the Stefan-Boltzmann law have already been given by Landsberg and de Vos and some adjustments by Menon and Agrawal. However, since then no much more has been done on this subject and we believe there are some relevant aspects yet to explore. In addition to the results previously found we calculate the thermodynamic potentials, the efficiency of the Carnot engine, the law for adiabatic processes and the heat capacity at constant volume. There is a region at which an interesting behavior of the thermodynamic potentials arise, maxima and minima appear for the $n-d$ BBR system at very high temperatures and low dimensionality, suggesting a possible application to cosmology. Finally we propose that an optimality criterion in a thermodynamic framework could have to do with the $3-d$ nature of the universe.

  7. Synthesis and thermodynamic properties of a new task-specific ionic liquid 1-butyl-3-methylimidazolium salicylate

    NASA Astrophysics Data System (ADS)

    Wang, Xiao-Dan; Han, Chun; Fan, Hong-Tao

    2015-07-01

    Task-specific ionic liquid 1-butyl-3-methylimidazolium salicylate ([BMI]Sal) was synthesized in two steps. In the temperature range of 298.15-353.15 K, the density and surface tension for pure ionic liquid were determined and the thermodynamic properties of the ionic liquid were discussed in terms of Glasser's theory. The standard molar entropy and lattice energy for [BMI]Sal have been estimated. In addition, the thermal expansion coefficient, ? = 5.53 × 10-4 K-1, calculated by the interstice model is in extreme agreement with ? (experimental) = 5.50 × 10-4 K-1.

  8. Thermodynamic and related properties of oxygen from the triple point to 300 K at pressures to 1000 bar

    NASA Technical Reports Server (NTRS)

    Weber, L. A.

    1977-01-01

    The results of an experimental program are presented in the form of PVT data in the temperature range 58 to 300 K at pressures up to 800 bar. Tables of the derived thermodynamic properties on isobars to 1000 bar are given, including density, internal energy, enthalpy, entropy, specific heats at constant volume and constant pressure, velocity of sound, and the surface derivatives (delta P/delta T) sub rho and (delta P/delta Rho) sub T. Auxiliary tables in engineering units are also given. The accuracy of the data is discussed and comparisons are made with previous data.

  9. Picosecond acoustics method for measuring the thermodynamical properties of solids and liquids at high pressure and high temperature.

    PubMed

    Decremps, F; Gauthier, M; Ayrinhac, S; Bove, L; Belliard, L; Perrin, B; Morand, M; Le Marchand, G; Bergame, F; Philippe, J

    2015-02-01

    Based on the original combination of picosecond acoustics and diamond anvils cell, recent improvements to accurately measure hypersonic sound velocities of liquids and solids under extreme conditions are described. To illustrate the capability of this technique, results are given on the pressure and temperature dependence of acoustic properties for three prototypical cases: polycrystal (iron), single-crystal (silicon) and liquid (mercury) samples. It is shown that such technique also enables the determination of the density as a function of pressure for liquids, of the complete set of elastic constants for single crystals, and of the melting curve for any kind of material. High pressure ultrafast acoustic spectroscopy technique clearly opens opportunities to measure thermodynamical properties under previously unattainable extreme conditions. Beyond physics, this state-of-the-art experiment would thus be useful in many other fields such as nonlinear acoustics, oceanography, petrology, in of view. A brief description of new developments and future directions of works conclude the article. PMID:24852260

  10. A switch function applied to the thermodynamic properties of steam near and not near the critical point

    NASA Astrophysics Data System (ADS)

    Woolley, H. W.

    1983-03-01

    A study is presented of the still-unsolved problem of estimating thermodynamic property values in a region intermediate between the critical region in which the scaling laws apply, and regions further from critical, where classical behavior prevails. A procedure has been developed in which a varying weighting function is used in obtaining a weighted “average” of the scaled and the classical Helmholtz free energy. Other properties are then obtained by differentiation. It is first demonstrated that it is fundamentally impossible for the “averaged” Helmholtz free energy and its first two derivatives to all be intermediate between the corresponding values from the scaled and the classical formulations. The procedure has been developed and tested for steam. The scaled function is the simple linear model of Murphy et al., the classical equation that of Pollak. The properties of power-weighted switch functions, particularly with respect to the behavior of higher-order derivatives, and the choice of the boundaries of the switching region, were examined in detail and optimized by proper choice of parameters. It is shown that a reasonably smooth transfer from the scaled to the classical region can be achieved as far as free energy, energy, and specific heat C V are concerned. For satisfactory behavior of all second derivative properties, the two formulations need to be more compatible in the switching region than they are in the present case.

  11. Standard thermodynamic properties of H3PO4(aq) over a wide range of temperatures and pressures.

    PubMed

    Ballerat-Busserolles, Karine; Sedlbauer, Josef; Majer, Vladimir

    2007-01-11

    The densities and heat capacities of solutions of phosphoric acid, 0.05 to 1 mol kg-1, were measured using flow vibrating tube densitometry and differential Picker-type calorimetry at temperatures up to 623 K and at pressures up to 28 MPa. The standard molar volumes and heat capacities of molecular H3PO4(aq) were obtained, via the apparent molar properties corrected for partial dissociation, by extrapolation to infinite dilution. The data on standard derivative properties were correlated simultaneously with the dissociation constants of phosphoric acid from the literature using the theoretically founded SOCW model. This made it possible to describe the standard thermodynamic properties, particularly the standard chemical potential, of both molecular and ionized phosphoric acid at temperatures up to at least 623 K and at pressures up to 200 MPa. This representation allows one to easily calculate the first-degree dissociation constant of H3PO4(aq). The performance of the SOCW model was compared with the other approaches for calculating the high-temperature dissociation constant of the phosphoric acid. Using the standard derivative properties, sensitively reflecting the interactions between the solute and the solvent, the high-temperature behavior of H3PO4(aq) is compared with that of other weak acids. PMID:17201442

  12. Lead-free solder alloys: Thermodynamic properties of the (Au + Sb + Sn) and the (Au + Sb) system.

    PubMed

    Hindler, Michael; Guo, Zhongnan; Mikula, Adolf

    2012-12-01

    The thermodynamic properties of liquid (Au-Sb-Sn) alloys were studied with an electromotive force (EMF) method using the eutectic mixture of KCl/LiCl with addition of SnCl2 as a liquid electrolyte. Activities of Sn in the liquid alloys were measured at three cross-sections with constant molar ratios of Au:Sb = 2:1, 1:1, and 1:2 with tin in the concentration range between 5 at.% and 90 at.% from the liquidus of the samples up to 1073 K. The integral Gibbs excess energies and the integral enthalpies at 873 K were calculated by Gibbs-Duhem integration. Additionally liquid Au-Sb alloys have been measured at 913 K with the EMF method as no reliable data for the Gibbs excess energies have been found in literature. The eutectic mixture of KCl/LiCl with addition of SbCl3 has been used as an electrolyte for the measurements. The Gibbs excess energies from the (Au + Sb) system were necessary for the integration of the thermodynamic properties of the ternary (Au + Sb + Sn) system. PMID:24926101

  13. First-principles study of the structural, electronic, dynamical, and thermodynamic properties of Li5AlO4

    NASA Astrophysics Data System (ADS)

    Guan, Qiushi; Chen, Xiaojun; Gao, Tao; Xiao, Chengjian; Zhao, Linjie; He, Jianchao; Long, Xinggui

    2015-10-01

    Pentalithium aluminate, Li5AlO4, has attracted increasing attention for its high lithium density and potential uses in tritium breeding materials and thermal batteries. In this work, the structural, electronic, lattice dynamical, and thermodynamic properties of ?- and ?-phase Li5AlO4 were investigated using first-principles density functional theory. The optimized structural parameters were consistent with the experimental values, with the absolute deviation being less than 2.5%. The indirect band gaps of ?- and ?-Li5AlO4 were 4.82 and 5.16 eV, respectively, showing that they are insulators. In addition, the vibrational properties of ?- and ?-Li5AlO4 were computed using density functional perturbation theory. By adding Born effective charges into the phonon calculations, the longitudinal optical-transverse optical (LO-TO) splittings were calculated. The optical modes at the ? point were categorized as Raman- and IR-active modes. Our results show that ?-Li5AlO4 is more polar and anisotropic than ?-Li5AlO4. Furthermore, their thermodynamic functions were determined using the calculated phonon density of states. The results were in good agreement with those of previous theoretical studies. The data presented in this work will help in the further characterization of Li5AlO4, which may be valuable for future experimental studies.

  14. Elastic, superconducting, and thermodynamic properties of the cubic metallic phase of AlH3 via first-principles calculations

    NASA Astrophysics Data System (ADS)

    Wei, Yong-Kai; Ge, Ni-Na; Ji, Guang-Fu; Chen, Xiang-Rong; Cai, Ling-Cang; Zhou, Su-Qin; Wei, Dong-Qing

    2013-09-01

    The lattice dynamic, elastic, superconducting, and thermodynamic properties of the high-pressure cubic metallic phase AlH3 are studied within density function theory. The calculated elastic modulus and phonon dispersion curves at various pressures indicate that the cubic phase is both mechanically and dynamically stable above 73 GPa. The superconducting transition temperature was calculated using Allen-Dynes modification of the McMillan formula based on the Bardeen-Cooper-Schrieffer theory. It is found that Tc approaches a linear decrease in the low pressure range at the rate dTC/dP ?-0.22 K/GPa but gradually decreases exponentially at higher pressure, and then it becomes 0 K upon further compression. The calculations indicate that Tc is about 2.042 K at 110 GPa, in agreement with experimental results. The soft phonon modes, especially the lowest acoustic mode, contribute almost 79% to the total electron-phonon coupling parameter s? for cubic AlH3 at 73 GPa. However, they disappear gradually with increasing pressure, showing a responsibility for the variation of Tc. The thermodynamic properties of cubic AlH3, such as the dependence of thermal expansion coefficient ?V on pressure and temperature, the specific heat capacity CP, as well as the electronic specific heat coefficient Cel, were also investigated by the quasi-harmonic approximation theory.

  15. KiSThelP: a program to predict thermodynamic properties and rate constants from quantum chemistry results.

    PubMed

    Canneaux, Sébastien; Bohr, Frédéric; Henon, Eric

    2014-01-01

    Kinetic and Statistical Thermodynamical Package (KiSThelP) is a cross-platform free open-source program developed to estimate molecular and reaction properties from electronic structure data. To date, three computational chemistry software formats are supported (Gaussian, GAMESS, and NWChem). Some key features are: gas-phase molecular thermodynamic properties (offering hindered rotor treatment), thermal equilibrium constants, transition state theory rate coefficients (transition state theory (TST), variational transition state theory (VTST)) including one-dimensional (1D) tunnelling effects (Wigner, and Eckart) and Rice-Ramsperger-Kassel-Marcus (RRKM) rate constants, for elementary reactions with well-defined barriers. KiSThelP is intended as a working tool both for the general public and also for more expert users. It provides graphical front-end capabilities designed to facilitate calculations and interpreting results. KiSThelP enables to change input data and simulation parameters directly through the graphical user interface and to visually probe how it affects results. Users can access results in the form of graphs and tables. The graphical tool offers customizing of 2D plots, exporting images and data files. These features make this program also well-suited to support and enhance students learning and can serve as a very attractive courseware, taking the teaching content directly from results in molecular and kinetic modelling. PMID:24190715

  16. Standard state thermodynamic properties of completely dissociated hydrochloric acid and aqueous sodium hydroxide at extreme temperatures and pressures.

    PubMed

    Djamali, Essmaiil; Cobble, James W

    2009-08-01

    Standard state thermodynamic properties for completely dissociated hydrochloric acid were fixed by ionic additivity, using the data from other strong electrolytes perrhenic acid, sodium perrhenate, and sodium chloride from 298.15 to 598.15 K and at p(sat). The standard electrode potential for the important silver-silver chloride electrode system and the equilibrium constants for the volatility of HCl from aqueous solutions were then calculated and compared with literature data. Using the experimental data from this study and auxiliary data from literature, the logarithm of the molal association constant of HCl at the critical temperature of water and at 673.15 K up to 1000 MPa was predicted from the unified theory of electrolytes (UTE). The standard state thermodynamic properties for completely dissociated aqueous sodium hydroxide were also calculated by ionic additivity over the same temperature range from aqueous sodium chloride, hydrochloric acid, and the dissociation constant of water. The results were compared with literature data. PMID:19606908

  17. Mechanical and thermodynamic properties of cubic YH2 under high pressure: Prediction from first-principles study

    NASA Astrophysics Data System (ADS)

    Li, Zhen-Li; Cheng, Xin-Lu

    2014-04-01

    First-principles calculations are used to investigate the mechanical and thermodynamic properties of cubic YH2 at different pressures and temperatures. The generalized gradient approximation (GGA) with Perdew-Burke-Ernzerhof (PBE) method is used to describe the exchange-correlation energy in the present work. The calculated equilibrium lattice constant a and bulk modulus B are in good accordance with the available experimental values. According to the Born-Huang criteria for mechanical stability, elastic constants are calculated from the strain-induced stress method in a pressure range from 0 to 67.1 GPa. Isotropic wave velocities and sound velocities are discussed in detail. It is found that the Debye temperature decreases monotonically with the increase of pressure and that YH2 has low anisotropy in both longitudinal and shear-wave velocities. The calculated elastic anisotropic factors indicate that YH2 has low anisotropy at zero pressure and that its elastic anisotropy increases as pressure increases. Through the quasi-harmonic Debye model, in which phononic effects are considered, the thermodynamic properties of YH2, such as the relations of (V-V0)/V0 to the temperature and the pressure, the dependences of heat capacity Cv and thermal expansion coefficient ? on temperature and pressure ranging from 0 to 2400 K and from 0 to 65 GPa, respectively, are also discussed.

  18. Theoretical study of thermodynamic properties and reaction rates of importance in the high-speed research program

    NASA Technical Reports Server (NTRS)

    Langhoff, Stephen; Bauschlicher, Charles; Jaffe, Richard

    1992-01-01

    One of the primary goals of NASA's high-speed research program is to determine the feasibility of designing an environmentally safe commercial supersonic transport airplane. The largest environmental concern is focused on the amount of ozone destroying nitrogen oxides (NO(x)) that would be injected into the lower stratosphere during the cruise portion of the flight. The limitations placed on NO(x) emission require more than an order of magnitude reduction over current engine designs. To develop strategies to meet this goal requires first gaining a fundamental understanding of the combustion chemistry. To accurately model the combustor requires a computational fluid dynamics approach that includes both turbulence and chemistry. Since many of the important chemical processes in this regime involve highly reactive radicals, an experimental determination of the required thermodynamic data and rate constants is often very difficult. Unlike experimental approaches, theoretical methods are as applicable to highly reactive species as stable ones. Also our approximation of treating the dynamics classically becomes more accurate with increasing temperature. In this article we review recent progress in generating thermodynamic properties and rate constants that are required to understand NO(x) formation in the combustion process. We also describe our one-dimensional modeling efforts to validate an NH3 combustion reaction mechanism. We have been working in collaboration with researchers at LeRC, to ensure that our theoretical work is focused on the most important thermodynamic quantities and rate constants required in the chemical data base.

  19. Polylogarithmic Representation of Radiative and Thermodynamic Properties of Thermal Radiation in a Given Spectral Range: II. Real-Body Radiation

    NASA Astrophysics Data System (ADS)

    Fisenko, Anatoliy I.; Lemberg, Vladimir

    2015-10-01

    There are several classes of materials and space objects for which the frequency dependence of the spectral emissivity is represented as a power series. Therefore, the study of the properties of thermal radiation for these real bodies is an important task for both fundamental science and industrial applications. The general analytical expressions for the thermal radiative and thermodynamic functions of a real body are obtained in a finite range of frequencies at different temperatures. The Stefan-Boltzmann law, total energy density, number density of photons, Helmholtz free energy density, internal energy density, enthalpy density, entropy density, heat capacity at constant volume, pressure, and total emissivity are expressed in terms of the polylogarithm functions. The obtained general expressions for the thermal radiative and thermodynamic functions are applied for the study of thermal radiation of liquid and solid zirconium carbide. These functions are calculated using experimental data for the frequency dependence of the normal spectral emissivity in the visible and near-infrared range at the melting (freezing) point. The gaps between the thermal radiative and thermodynamic functions of liquid and solid zirconium carbide are observed. The general analytical expressions obtained can easily be presented in the wavenumber domain.

  20. First Principles Calculations of Structural, Electronic, Thermodynamic and Thermal Properties of BaxSr1-xTe Ternary Alloys

    NASA Astrophysics Data System (ADS)

    Chelli, S.; Meradji, H.; Amara Korba, S.; Ghemid, S.; El Haj Hassan, F.

    2014-12-01

    The structural, electronic thermodynamic and thermal properties of BaxSr1-xTe ternary mixed crystals have been studied using the ab initio full-potential linearized augmented plane wave (FP-LAPW) method within density functional theory (DFT). In this approach, the Perdew-Burke-Ernzerhof-generalized gradient approximation (PBE-GGA) was used for the exchange-correlation potential. Moreover, the recently proposed modified Becke Johnson (mBJ) potential approximation, which successfully corrects the band-gap problem was also used for band structure calculations. The ground-state properties are determined for the cubic bulk materials BaTe, SrTe and their mixed crystals at various concentrations (x = 0.25, 0.5 and 0.75). The effect of composition on lattice constant, bulk modulus and band gap was analyzed. Deviation of the lattice constant from Vegard's law and the bulk modulus from linear concentration dependence (LCD) were observed for the ternary BaxSr1-xTe alloys. The microscopic origins of the gap bowing were explained by using the approach of Zunger and co-workers. On the other hand, the thermodynamic stability of these alloys was investigated by calculating the excess enthalpy of mixing, ?Hm as well as the phase diagram. It was shown that these alloys are stable at high temperature. Thermal effects on some macroscopic properties of BaxSr1-xTe alloys were investigated using the quasi-harmonic Debye model, in which the phononic effects are considered.

  1. ON THE SELF-CONSISTENT STATISTICAL THEORY OF STRUCTURAL, DYNAMICAL, AND THERMODYNAMIC SURFACE PROPERTIES OF ANHARMONIC CRYSTALS II:. The Properties of Arbitrary Oriented Surfaces of the Two-Dimensional Model with Square Lattice

    NASA Astrophysics Data System (ADS)

    Zubov, V. I.; Banyeretse, F.

    The correlative unsymmetrized self-consistent field method is used to study surface properties of the two-dimensional model of an anharmonic crystal with square lattice having various Miller indices. The lattice relaxation, the amplitudes of atomic vibrations and the thermodynamic surface functions are calculated. The typical nonsingular and vicinal surfaces are considered. The dependence of thermodynamic surface functions on the surface orientation is obtained.

  2. Structural, thermodynamic, mechanical, and magnetic properties of FeW system

    SciTech Connect

    Ren, Q. Q.; Fan, J. L.; Han, Y.; Gong, H. R.

    2014-09-07

    The Fe-W system is systematically investigated through a combined use of first-principles calculation, cluster expansion, special quasirandom structures, and experiments. It is revealed that the ferromagnetic state of BCC Fe-W solid solution has lower heat of formation than its nonmagnetic state within the entire composition range, and intermetallic ?-Fe{sub 2}W and ?-Fe{sub 7}W{sub 6} phases are energetically favorable with negative heats of formation. Calculations also show that the Fe-W solid solution has much lower coefficient of thermal expansion than its mechanical mixture, and that the descending sequence of temperature-dependent elastic moduli of each Fe-W solid solution is E?>?G?>?B. Moreover, magnetic state should have an important effect on mechanical properties of Fe-W phases, and electronic structures can provide a deeper understanding of various properties of Fe-W. The derived results agree well with experimental observations, and can clarify two experimental controversies regarding structural stability and magnetic property of Fe-W phases in the literature.

  3. Thermodynamic and aggregation properties of aza- and imino-substituted gemini surfactants designed for gene delivery.

    PubMed

    Wettig, Shawn D; Wang, Chuanzhong; Verrall, Ronald E; Foldvari, Marianna

    2007-02-21

    Improving the efficiency of gene delivery by using non-viral vectors is currently an area of considerable research interest. Novel derivatives of gemini surfactants having aza- (12-5N-12, 12-7N-12, 12-8N-12) and imino- (12-7NH-12) substituted spacer groups and C12 tails have been designed to improve DNA transfection. Physicochemical characterization of micelle and interfacial properties of these cationic compounds are reported. The effect of these substitutions on the aggregation properties of the gemini surfactants is discussed in the context of results for the 12-s-12 and 12-EOx-12 gemini series, previously reported in the literature. Aza substitution results in a spacer of intermediate hydrophobicity to the above series, reflected by the magnitude of both the critical micelle concentrations and head group areas. Enthalpy and apparent molar volume of micellization data illustrate the differences in the aggregation properties that result from the bulkier and more hydrophobic aza-substituent in the spacer as compared to an ether oxygen (for the 12-EOx-12 series) containing spacer. The 12-7N-12 and 12-8N-12 compounds show aberrant features in the surface tension and enthalpy of dilution results that are not observed for the 12-5N-12 and 12-7NH-12 compounds. Premicelle association is considered to be a source of this behaviour. PMID:17287881

  4. The calculations of thermodynamic and opto-electronics properties of Pb1-xCaxSe semiconducting ternary Alloys

    NASA Astrophysics Data System (ADS)

    Sifi, C.; Slimani, M.; Meradji, H.

    2012-06-01

    The ab initio full potential linearized augmented plane wave (FP-LAPW) method within density functional theory was applied to study the effect of composition on the structural and electronic properties Pbl-xCaxSe temary alloys. The effect of composition on lattice parameter, bulk modulus, band gap was investigate. Deviations of the lattice constant from Vegard's law and the bulk modulus from linear concentration dependence were observed. In addition, the microscopic origins of compositional disorder were explained by using the approach of Zunger and co-workers. The disorder parameter (gap bowing) was found to be strong and was mainly caused by the chemical charge transfer effect. The volume deformation contributions for all alloys were also found to be significant, while the structural relaxation contributions to the gap bowing parameter were relatively smaller. On the other hand, the thermodynamic stability and optical properties are attempted in the calculations. The calculated refractive indices and optical dielectric constants for the parent compounds show better agreement with the known data when the Moss relation is used. Compositional dependence of the optical and electronic properties studied is also investigated.

  5. Theoretical calculations for structural, elastic, and thermodynamic properties of RuN{sub 2} under high pressure

    SciTech Connect

    Dong, Bing; Zhou, Xiao-Lin E-mail: lkworld@126.com; Chang, Jing; Liu, Ke E-mail: lkworld@126.com

    2014-08-07

    The structural and elastic properties of RuN{sub 2} were investigated through the first-principles calculation using generalized gradient approximation (GGA) and local density approximation (LDA) within the plane-wave pseudopotential density functional theory. The obtained equilibrium structure and mechanical properties are in excellent agreement with other theoretical results. Then we compared the elastic modulus of RuN{sub 2} with several other isomorphic noble metal nitrides. Results show that RuN{sub 2} can nearly rival with OsN{sub 2} and IrN{sub 2}, which indicate RuN{sub 2} is a potentially ultra-incompressible and hard material. By the elastic stability criteria, it is predicted that RuN{sub 2} is stable in our calculations (0–100?GPa). The calculated B/G ratios indicate that RuN{sub 2} possesses brittle nature at 0?GPa and when the pressure increases to 13.4?GPa (for LDA) or 20.8?GPa (for GGA), it begins to prone to ductility. Through the quasi-harmonic Debye model, we also investigated the thermodynamic properties of RuN{sub 2}.

  6. Application of the tetraphenylphosphonium tetraphenylborate (TPTB) assumption to the thermodynamic properties of solvated ions in dimethylsulfoxide.

    PubMed

    Warmi?ska, Dorota; Stangret, Janusz

    2012-03-01

    The extra-thermodynamic tetraphenylphosphonium tetraphenylborate assumption has been tested for dimethylsulfoxide using ATR FTIR spectroscopy. Solute-affected DMSO spectra show that, contrary to the TPTB assumption, the charge density on BPh(4)(-) and Ph(4)P(+) ions is sufficiently high to influence the DMSO molecules orientation with respect to the cation and to the anion. Apparently, the Ph(4)P(+) cation does not affect the structure of DMSO whereas the BPh(4)(-) anion clearly breaks it up. Our results indicate that the TPTB extra-thermodynamic assumption is not a sound basis for splitting thermodynamic values obtained for DMSO solutions into ionic contributions. PMID:22286588

  7. Calculation of the thermodynamic properties of fuel-vapor species from spectroscopic data

    SciTech Connect

    Green, D.W.

    1980-09-01

    Measured spectroscopic data, estimated molecular parameters, and a densty-of-states model for electronic structure have been used to calculate thermodynamic functions for gaseous ThO, ThO/sub 2/, UO, UO/sub 2/, UO/sub 3/, PuO, and PuO/sub 2/. Various methods for estimating parameters have been considered and numerically evaluated. The sensitivity of the calculated thermodynamic functions to molecular parameters has been examined quantitatively. New values of the standard enthalpies of formation at 298.15/sup 0/K have been derived from the best available ..delta..G/sup 0//sub f/ equations and the calculated thermodynamic functions. Estimates of the uncertainties have been made for measured and estimated data as well as for various mathematical and physical approximations. Tables of the thermodynamic functions to 6000/sup 0/K are recommended for gaseous thorium, uranium, and plutonium oxides.

  8. Density functional theory study of the thermodynamic and elastic properties of Ni-based superalloys.

    PubMed

    Wu, Xiaoxia; Wang, Chongyu

    2015-07-29

    The thermophysical properties of Ni-based single-crystal superalloys were investigated using first-principles calculations combined with the quasiharmonic approximation. The effect of alloying elements X (X = Re, Ru, Ta, W, Mo, Cr, and Co) on the thermophysical properties of the ?-Ni and ?'-Ni3Al phases was investigated. The calculations showed that alloying can effectively adjust the lattice misfit between the two phases, and Cr can suppress lattice misfit and may improve the creep resistance of alloys. At 0?K, doping with refractory elements leads to tetragonal shear softening of the ?-Ni phase. For ?-Ni, Re, Ru, Cr, and Co slightly increase c44, while Mo, W, and Ta decrease c44. Importantly, high-temperature relative hardening was found to occur close to the service temperature of the superalloy, at which Ru and Cr increase c' and Mo and W increase c44 of ?-Ni. For the ?'-Ni3Al phase, all of the alloying elements except Co considerably increase c' and c44. Re and W at the Al site were found to most effectively harden the ?'-Ni3Al phase. The thermophysical and elastic properties were fully understood by analysis of the electronic structures and phonon spectra. It was found that the electronic density of states (DOS) can account for elastic hardening due to alloying. The phonon spectra along with electronic DOS analysis showed that alloying not only strengthens the first nearest neighbor Ni-X bond through additional d-d hybridization, but it is also important for stiffening the second nearest neighbor Al-X bonding through p-band filling. PMID:26139707

  9. Density functional theory study of the thermodynamic and elastic properties of Ni-based superalloys

    NASA Astrophysics Data System (ADS)

    Wu, Xiaoxia; Wang, Chongyu

    2015-07-01

    The thermophysical properties of Ni-based single-crystal superalloys were investigated using first-principles calculations combined with the quasiharmonic approximation. The effect of alloying elements X (X = Re, Ru, Ta, W, Mo, Cr, and Co) on the thermophysical properties of the ?-Ni and ??-Ni3Al phases was investigated. The calculations showed that alloying can effectively adjust the lattice misfit between the two phases, and Cr can suppress lattice misfit and may improve the creep resistance of alloys. At 0?K, doping with refractory elements leads to tetragonal shear softening of the ?-Ni phase. For ?-Ni, Re, Ru, Cr, and Co slightly increase c44, while Mo, W, and Ta decrease c44. Importantly, high-temperature relative hardening was found to occur close to the service temperature of the superalloy, at which Ru and Cr increase c? and Mo and W increase c44 of ?-Ni. For the ??-Ni3Al phase, all of the alloying elements except Co considerably increase c? and c44. Re and W at the Al site were found to most effectively harden the ??-Ni3Al phase. The thermophysical and elastic properties were fully understood by analysis of the electronic structures and phonon spectra. It was found that the electronic density of states (DOS) can account for elastic hardening due to alloying. The phonon spectra along with electronic DOS analysis showed that alloying not only strengthens the first nearest neighbor Ni-X bond through additional d-d hybridization, but it is also important for stiffening the second nearest neighbor Al-X bonding through p-band filling.

  10. Prediction of thermodynamic properties of natural gases using Monte Carlo simulations

    NASA Astrophysics Data System (ADS)

    Piyanzina, I.; Lysogorskiy, Yu; Nedopekin, O.

    2012-11-01

    In this paper an applications of Monte-Carlo simulation in natural gas production is presented. We have investigated model of natural gas of the Bavlinskoye deposit located in the southeast of the Republic of Tatarstan. For this natural gas and for pure methane and ethane gases we have obtained thermal expansivity, isothermal compressibility, compressibility factor, heat capacity, Joule-Thompson coefficient and density at pressures up to 110 MPa at deposit temperature (463 K). Also we have obtained vapor pressures and liquid-vapor phase diagrams. Simulated properties for methane are in a good agreement with available experimental data.

  11. First principle study of elastic and thermodynamic properties of ZrZn{sub 2} and HfZn{sub 2} under high pressure

    SciTech Connect

    Sun, Na; Zhang, Xinyu Ning, Jinliang; Zhang, Suhong; Liang, Shunxing; Ma, Mingzhen; Liu, Riping; Qin, Jiaqian

    2014-02-28

    A comprehensive investigation of the structural, elastic, and thermodynamic properties for Laves-phases ZrZn{sub 2} and HfZn{sub 2} are conducted using density functional total energy calculations combined with the quasi-harmonic Debye model. The optimized lattice parameters of ZrZn{sub 2} and HfZn{sub 2} compare well with available experimental values. We estimated the mechanical behaviors of both compounds under compression, including mechanical stability, Young's modulus, Poisson's ratio, ductility, and anisotropy. Additionally, the thermodynamic properties as a function of pressure and temperature are analyzed and found to be in good agreement with the corresponding experimental data.

  12. First principle study of elastic and thermodynamic properties of ZrZn2 and HfZn2 under high pressure

    NASA Astrophysics Data System (ADS)

    Sun, Na; Zhang, Xinyu; Qin, Jiaqian; Ning, Jinliang; Zhang, Suhong; Liang, Shunxing; Ma, Mingzhen; Liu, Riping

    2014-02-01

    A comprehensive investigation of the structural, elastic, and thermodynamic properties for Laves-phases ZrZn2 and HfZn2 are conducted using density functional total energy calculations combined with the quasi-harmonic Debye model. The optimized lattice parameters of ZrZn2 and HfZn2 compare well with available experimental values. We estimated the mechanical behaviors of both compounds under compression, including mechanical stability, Young's modulus, Poisson's ratio, ductility, and anisotropy. Additionally, the thermodynamic properties as a function of pressure and temperature are analyzed and found to be in good agreement with the corresponding experimental data.

  13. The Relation Between Thermodynamic and Structural Properties and Cellular Uptake of Peptides Containing Tryptophan and Arginine

    PubMed Central

    Shirani, Ali; Shahbazi Mojarrad, Javid; Mussa Farkhani, Samad; yari khosroshahi, Ahmad; Zakeri-Milani, Parvin; Samadi, Naser; Sharifi, Simin; Mohammadi, Samaneh; Valizadeh, Hadi

    2015-01-01

    Purpose: Cell-penetrating peptides (CPPs) are used for delivering drugs and other macromolecular cargo into living cells. In this paper, we investigated the relationship between the structural/physicochemical properties of four new synthetic peptides containing arginine-tryptophan in terms of their cell membrane penetration efficiency. Methods: The peptides were prepared using solid phase synthesis procedure using FMOC protected amino acids. Fluorescence-activated cell sorting and ?uorescence imaging were used to evaluate uptake efficiency. Prediction of the peptide secondary structure and estimation of physicochemical properties was performed using the GOR V method and MPEx 3.2 software (Wimley-White scale, helical wheel projection and total hydrophobic moment). Results: Our data showed that the uptake e?ciency of peptides with two tryptophans at the C- and N-terminus were significantly higher (about 4-fold) than that of peptides containing three tryptophans at both ends. The distribution of arginine at both ends also increased the uptake e?ciency 2.52- and 7.18-fold, compared with arginine distribution at the middle of peptides. Conclusion: According to the obtained results the value of transfer free energies of peptides from the aqueous phase to membrane bilayer could be a good predictor for the cellular uptake efficiency of CPPs. PMID:26236653

  14. Molecular dynamics simulation of thermodynamic and transport properties of H-bonded low-temperature substances

    NASA Astrophysics Data System (ADS)

    Tychengulova, A.; Aldiyarov, A.; Drobyshev, A.

    2015-06-01

    The results of modeling of isotopic water mixture clusters in nitrogen and argon cryomatrices are presented. Earlier, our experimental studies of water mixture in cryomatrix have shown that changes in the concentration of analyte in matrix leads to a splitting of the absorption bands characteristic frequencies of the molecules in the IR spectrum. Moreover the multiplicity of characteristic absorption bands in the IR spectrum remained unchanged during heating of the samples from the condensation temperature to the sublimation temperature of the matrix element. In order to find out what structure of clusters is responsible for the immutability of the absorption bands in the vibrational spectrum during thermal cycling of the samples, computer research of water molecules enclosed in nitrogen and argon cryomatrices by the molecular dynamics simulation was conducted. For this purpose, theoretical studies were carried out using computer software packages, that implement used by us semi empirical and ab initio molecular dynamics methods. As a result of the research, the data must be obtained are of theoretical interest for summarizing the physical and chemical properties of systems, consisting of water molecules, and their combination with inert gases for studying the properties of molecular crystals composed of small molecules.

  15. Effects of Phosphine-Carbene Substitutions on the Electrochemical and Thermodynamic Properties of Nickel Complexes

    SciTech Connect

    Galan, Brandon R.; Wiedner, Eric S.; Helm, Monte L.; Linehan, John C.; Appel, Aaron M.

    2014-05-12

    Nickel(II) complexes containing chelating N-heterocyclic carbene-phosphine ligands ([NiL2](BPh4)2, for which L = [MeIm(CH2)2PR2]) have been synthesized for the purpose of studying how this class of ligand effects the electrochemical properties compared to the nickel bis- diphosphine analogues. The nickel complexes were synthesized and characterized by x-ray crystallography and electrochemical methods. Based on the half wave potentials (E1/2), substitution of an NHC for one of the phosphines in a diphoshine ligand results in shifts in potential to 0.6 V to 1.2 V more negative than the corresponding nickel bis-diphosphine complexes. These quantitative results highlight the substantial effect that NHC ligands can have upon the electronic properties of the metal complexes. BRG, JCL, and AMA acknowledge the support by the US Department of Energy Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences. MLH acknoledges the support of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the US Department of Energy, Office of Science, Office of Basic Energy Sciences. Pacific Northwest National Laboratory is operated by Battelle for the US Department of Energy.

  16. First principles study of the structural, mechanical, phonon, optical, and thermodynamic properties of half-Heusler (HH) compound NbFeSb

    NASA Astrophysics Data System (ADS)

    Çoban, C.; Çolako?lu, K.; Çiftçi, Y. Ö.

    2015-09-01

    We studied the structural, mechanical, phonon, optical and thermodynamic properties of MgAgAs-based NbFeSb compound by means of first-principles based on the density functional theory. The calculated lattice constant is in good agreement with the available experimental data. The electronic structure and corresponding density of states (DOS) were also calculated to give insight into the bonding mechanism and an indirect band gap was observed as ?1.77 eV, which is significantly higher than the previously reported one (0.529 eV). The elastic properties such as shear modulus, Young’s modulus etc under pressure, up to 65 GPa, were analyzed. The phonon dispersion curves, one-phonon DOS, and optical properties were obtained. In addition, the thermodynamic properties such as heat capacity, Debye temperature etc of NbFeSb were calculated at various temperatures and pressures by applying the quasi-harmonic Debye model.

  17. The Extended Thermodynamic Properties of a topological Taub-NUT/Bolt-AdS spaces

    E-print Network

    Chong Oh Lee

    2015-10-21

    We consider the extended thermodynamic quantities of higher dimensional topological Taub-NUT/Bolt-AdS black holes with a cosmological constant treated as a pressure and find their general form for arbitrary dimensions and the thermodynamics of these configurations is argued to some extent. In particular by introducing Gibbs free energy, it is found out to be a new thermodynamically stable region of these black holes. At an equilibrium condition we find an entropy of a NUT solution, volume, and latent heat are negative where the Clapeyron equation is satisfied for these thermodynamic quantities. These negative volume and entropy may be interpreted as that the environment applies work to the system in the process of the Taub-NUT-AdS black hole formation, and such negative latent heat may indicate a net release of latent energy back into the environment because of evaporating of the system. Intriguingly, we also find that like the AdS black hole case, Taub-Bolt-AdS black hole with two phases (phase of small and large black holes) occurs before a transformation to a thermodynamically stable phase.

  18. Thermodynamic properties for polycyclic systems by non-calorimetric methods. Progress report, August 1, 1992--September 30, 1993

    SciTech Connect

    Steele, W.V.; Chirico, R.D.; Klots, T.D.

    1993-03-01

    A detailed vibrational spectroscopic study of furan, pyrrole, and thiophene has been completed. These compounds form part of the base of five-membered ring systems on which the rest of the research program will be built Several methyl-substituted derivatives were also studied. The results will be used to confirm the model for alkyl- substitution in the ring systems. Gas-phase spectra and fundamental- frequency assignments were completed for 2,3- and 2,5-dihydrofuran. Those compounds initiate work on ring-puckering within the research program. A paper describing the need for third virial estimation, when using the virial equation of state to derive thermodynamic properties at pressures greater than 1 bar was completed.

  19. Tables of critical-flow functions and thermodynamic properties for methane and computational procedures for both methane and natural gas

    NASA Technical Reports Server (NTRS)

    Johnson, R. C.

    1972-01-01

    Procedures for calculating the mass flow rate of methane and natural gas through nozzles are given, along with the FORTRAN 4 subroutines used to make these calculations. Three sets of independent variables are permitted in these routines. In addition to the plenum pressure and temperature, the third independent variable is either nozzle exit pressure, Mach number, or temperature. A critical-flow factor that becomes a convenient means for determining the mass flow rate of methane through critical-flow nozzles is tabulated. Other tables are included for nozzle throat velocity and critical pressure, density, and temperature ratios, along with some thermodynamic properties of methane, including compressibility factor, enthalpy, entropy, specific heat, specific-heat ratio, and speed of sound. These tabulations cover a temperature range from 120 to 600 K and pressures to 3 million N/sq m.

  20. Thermodynamic Properties of CO{sub 2} Capture Reaction by Solid Sorbents: Theoretical Predictions and Experimental Validations

    SciTech Connect

    Duan, Yuhua; Luebke, David; Pennline, Henry; Li, Liyu; King, David; Zhang; Keling; Zhao; Lifeng; Xiao, Yunhan

    2012-01-01

    It is generally accepted that current technologies for capturing CO{sub 2} are still too energy intensive. Hence, there is a critical need for development of new materials that can capture CO{sub 2} reversibly with acceptable energy costs. Accordingly, solid sorbents have been proposed to be used for CO{sub 2} capture applications through a reversible chemical transformation. By combining thermodynamic database mining with first principles density functional theory and phonon lattice dynamics calculations, a theoretical screening methodology to identify the most promising CO{sub 2} sorbent candidates from the vast array of possible solid materials has been proposed and validated. The calculated thermodynamic properties of different classes of solid materials versus temperature and pressure changes were further used to evaluate the equilibrium properties for the CO{sub 2} adsorption/desorption cycles. According to the requirements imposed by the pre- and post- combustion technologies and based on our calculated thermodynamic properties for the CO{sub 2} capture reactions by the solids of interest, we were able to screen only those solid materials for which lower capture energy costs are expected at the desired pressure and temperature conditions. These CO{sub 2} sorbent candidates were further considered for experimental validations. In this presentation, we first introduce our screening methodology with validating by solid dataset of alkali and alkaline metal oxides, hydroxides and bicarbonates which thermodynamic properties are available. Then, by studying a series of lithium silicates, we found that by increasing the Li{sub 2}O/SiO{sub 2} ratio in the lithium silicates their corresponding turnover temperatures for CO{sub 2} capture reactions can be increased. Compared to anhydrous K{sub 2}CO{sub 3}, the dehydrated K{sub 2}CO{sub 3}?1.5H{sub 2}O can only be applied for post-combustion CO{sub 2} capture technology at temperatures lower than its phase transition (to anhydrous phase) temperature, which depends on the CO{sub 2} pressure and the steam pressure with the best range being PH{sub 2}O?1.0 bar. Above the phase-transition temperature, the sorbent will be regenerated into anhydrous K{sub 2}CO{sub 3}. Our theoretical investigations on Na-promoted MgO sorbents revealed that the sorption process takes place through formation of the Na{sub 2}Mg(CO{sub 3}){sub 2} double carbonate with better reaction kinetics over porous MgO, that of pure MgO sorbent. The experimental sorption tests also indicated that the Na-promoted MgO sorbent has high reactivity and capacity towards CO{sub 2} sorption and can be easily regenerated either through pressure or temperature swing processes.

  1. Calculation of the absolute thermodynamic properties of association of host-guest systems from the intermolecular potential of mean force.

    PubMed

    Ghoufi, Aziz; Malfreyt, Patrice

    2006-12-14

    The authors report calculations of the intermolecular potential of mean force (PMF) in the case of the host-guest interaction. The host-guest system is defined by a water soluble calixarene and a cation. With an organic cation such as the tetramethylammonium cation, the calixarene forms an insertion complex, whereas with the Lanthane cation, the supramolecular assembly is an outer-sphere complex. The authors apply a modified free energy perturbation method and the force constraint technique to establish the PMF profiles as a function of the separation distance between the host and guest. They use the PMF profile for the calculation of the absolute thermodynamic properties of association that they compare to the experimental values previously determined. They finish by giving some structural features of the insertion and outer-sphere complexes at the Gibbs free energy minimum. PMID:17176145

  2. Analysis of elevated temperature data for thermodynamic properties of selected radionuclides

    SciTech Connect

    Wruck, D.A.; Palmer, C.E.A.

    1997-08-01

    This report is a review of chemical thermodynamic data for Ni, Zr, Tc, U, Np, Pu and Am in aqueous solutions at elevated temperatures. Thermodynamic data for aqueous reactions over the temperature range 20-150{degrees}C are needed for geochemical modeling studies of the Yucca Mountain Project. The present review is focused on the aqueous complexes relevant to expected conditions in the Yucca Mountain region: primarily the hydroxide, carbonate, sulfate and fluoride complexes with the metal ions. Existing thermodynamic data are evaluated, and means of extrapolating 25{degrees}C data to the temperatures of interest are discussed. There will be a separate review of solubility data for relevant Ni, Zr, Tc, Np, Pu and Am compounds.

  3. On the Thermodynamics and Other Constitutive Properties of a Class of Strongly Magnetized Matter Observed in Astrophysics

    NASA Astrophysics Data System (ADS)

    Berdichevsky, Daniel B.; Schefers, Kendric

    2015-05-01

    It is shown that the occurrence of magnetization work is a consistent thermodynamic explanation of the property of anti-correlation between temperature and density of the electrons gas in a class of magnetic-field-dominated structures observed in the interplanetary medium. In this model, a 7/4 scaling ratio for magnetization work to electron-gas work explains the often observed anomalous adiabatic polytropic exponent {{? }a}=1/2. This interpretation is built on the theoretical conjecture of a matter state having spatial confinement of most hadronic elements of matter, i.e., matter held in place by the action of what is here denominated as a “super-strong” magnetic field, which together with the plasma it contains satisfies—on medium to large spatial-temporal scales—ideal magnetohydrodynamics. Several elements of the interpretation are tested for a case study, the flux-rope (FR) structure passing Wind SC on 1998 June 2. This allows us to extract, for a 185 s sample interval inside the FR, the following constitutive properties of this diamagnetic state of matter: (i) sound speed, (ii) thermal temperature, (iii) magnetic permeability, and (iv) a low limit to its dielectric permittivity. The intervals of coherence, i.e., thermodynamic homogeneity, extend from a few to many 104 km for plasma and magnetic field average with a sampling rate of 3s per value. We point out that this state of matter, which we identify to be an amorphous three-dimensional Langmuir lattice, differs from other materials studied in the laboratory at extreme low temperatures and is well described as BCS-superconductors because in our case we understand that (a) the magnetic permeability is non-zero, and (b) substantial field-aligned, convected-current density exists.

  4. A review of reaction rates and thermodynamic and transport properties for the 11-species air model for chemical and thermal nonequilibrium calculations to 30000 K

    NASA Technical Reports Server (NTRS)

    Gupta, Roop N.; Yos, Jerrold M.; Thompson, Richard A.

    1989-01-01

    Reaction rate coefficients and thermodynamic and transport properties are provided for the 11-species air model which can be used for analyzing flows in chemical and thermal nonequilibrium. Such flows will likely occur around currently planned and future hypersonic vehicles. Guidelines for determining the state of the surrounding environment are provided. Approximate and more exact formulas are provided for computing the properties of partially ionized air mixtures in such environments.

  5. Study of Thermodynamic Properties of Zinc-Blende Semiconductors:. Temperature and Pressure Dependences

    NASA Astrophysics Data System (ADS)

    Hieu, Ho Khac; Hung, Vu Van

    Using the statistical moment method (SMM), the temperature and pressure dependences of thermodynamic quantities of zinc-blende-type semiconductors have been investigated. The analytical expressions of the nearest-neighbor distances, the change of volumes and the mean-square atomic displacements (MSDs) have been derived. Numerical calculations have been performed for a series of zinc-blende-type semiconductors: GaAs, GaP, GaSb, InAs, InP and InSb. The agreement between our calculations and both earlier other theoretical results and experimental data is a support for our new theory in investigating the temperature and pressure dependences of thermodynamic quantities of semiconductors.

  6. Properties of hadronic systems according to the non-extensive self-consistent thermodynamics

    SciTech Connect

    Deppman, A.

    2014-11-11

    The non-extensive self-consistent theory describing the thermodynamics of hadronic systems at high temperatures is used to derive some thermodynamical quantities, as pressure, entropy, speed of sound and trace-anomaly. The calculations are free of fitting parameters, and the results are compared to lattice QCD calculations, showing a good agreement between theory and data up to temperatures around 175 MeV. Above this temperature the effects of a singularity in the partition function at T{sub o} = 192 MeV results in a divergent behaviour in respect with the lattice calculation.

  7. Halocarbons in the environment: estimates of thermodynamic properties for aqueous chloroethylene species and their stabilities in natural settings

    NASA Astrophysics Data System (ADS)

    Haas, Johnson R.; Shock, Everett L.

    1999-10-01

    Standard partial molal thermodynamic parameters for the aqueous chlorinated-ethylene species, perchloroethylene (PCE), trichloroethylene (TCE), 1,1-dichloroethylene (1,1-DCE), cis-1,2-dichloroethylene (cis-1,2-DCE), trans-1,2-dichloroethylene (trans-1,2,-DCE), and vinyl chloride (VC) have been estimated by using experimental gas-solubility data and correlation algorithms. The provided thermodynamic values may be used to calculate properties of reactions involving the aqueous chloroethylene species at a wide range of temperatures and pressures. Estimated values for the chloroethylenes were used, along with published values for minerals, gases, aqueous ions, and aqueous neutral organic species, to calculate the stability of chloroethylene species in equilibrium with the minerals magnetite, hematite, pyrite, and pyrrhotite in the subsurface. Estimated values for the aqueous chloroethylenes were also used to calculate reduction potentials for microbially-mediated reductive dechlorination half-reactions at elevated temperatures. Calculations indicate that all aqueous chloroethylene species are energetically favored to decompose to ethylene(aq) under a wide range of conditions in the subsurface, by both abiotic and biotic pathways. Anaerobic microbially mediated degradation is especially favored under conditions at least sufficiently reducing to promote sulfate-reduction, but not under conditions sufficient for microbial denitrification, pyrolusite reduction, or ferric-iron reduction.

  8. GASP - THERMODYNAMIC AND TRANSPORT PROPERTIES OF HELIUM, METHANE, NEON, NITROGEN, CARBON MONOXIDE, CARBON DIOXIDE, OXYGEN, AND ARGON

    NASA Technical Reports Server (NTRS)

    Hendricks, R. C.

    1994-01-01

    A computer program, GASP, has been written to calculate the thermodynamic and transport properties of argon, carbon dioxide, carbon monoxide, fluorine, methane, neon, nitrogen, and oxygen. GASP accepts any two of pressure, temperature, or density as input. In addition, entropy and enthalpy are possible inputs. Outputs are temperature, density, pressure, entropy, enthalpy, specific heats, expansion coefficient, sonic velocity, viscosity, thermal conductivity, and surface tension. A special technique is provided to estimate the thermal conductivity near the thermodynamic critical point. GASP is a group of FORTRAN subroutines. The user typically would write a main program that invoked GASP to provide only the described outputs. Subroutines are structured so that the user may call only those subroutines needed for his particular calculations. Allowable pressures range from 0.l atmosphere to 100 to l,000 atmospheres, depending on the fluid. Similarly, allowable pressures range from the triple point of each substance to 300 degrees K to 2000 degrees K, depending on the substance. The GASP package was developed to be used with heat transfer and fluid flow applications. It is particularly useful in applications of cryogenic fluids. Some problems associated with the liquefication, storage, and gasification of liquefied natural gas and liquefied petroleum gas can also be studied using GASP. This program is written in FORTRAN IV for batch execution and is available for implementation on IBM 7000 series computers. GASP was developed in 1971.

  9. Quantum chemical vibrational study, molecular property, FTIR, FT-Raman spectra, NBO, HOMO-LUMO energies and thermodynamic properties of 1-methyl-2-phenyl benzimidazole

    NASA Astrophysics Data System (ADS)

    Karnan, M.; Balachandran, V.; Murugan, M.; Murali, M. K.

    2014-09-01

    The solid phase FT-IR and FT-Raman spectra of 1-methyl-2-phenyl benzimidazole (MPBZ) have been recorded in the condensed state. In this work, experimental and theoretical study on the molecular structure, quantum chemical calculations of energies and vibrational wavenumbers of MPBZ is presented. The vibrational frequencies of the title compound were obtained theoretically by DFT/B3LYP calculations employing the standard 6-311+G(d,p) and 6-311++G(d,p) basis set for optimized geometry and were compared with Fourier transform infrared spectrum (FTIR) in the region of 4000-400 cm-1 and with Fourier transform Raman spectrum in the region of 4000-100 cm-1. Complete vibrational assignments, analysis and correlation of the fundamental modes for the title compound were carried out. The vibrational harmonic frequencies were scaled using scale factor, yielding a good agreement between the experimentally recorded and the theoretically calculated values. The study is extended to calculate the HOMO-LUMO energy gap, NBO, mapped molecular electrostatic potential (MEP) surfaces, polarizability, Mulliken charges and thermodynamic properties of the title compound.

  10. Quantum chemical vibrational study, molecular property, FTIR, FT-Raman spectra, NBO, HOMO-LUMO energies and thermodynamic properties of 1-methyl-2-phenyl benzimidazole.

    PubMed

    Karnan, M; Balachandran, V; Murugan, M; Murali, M K

    2014-09-15

    The solid phase FT-IR and FT-Raman spectra of 1-methyl-2-phenyl benzimidazole (MPBZ) have been recorded in the condensed state. In this work, experimental and theoretical study on the molecular structure, quantum chemical calculations of energies and vibrational wavenumbers of MPBZ is presented. The vibrational frequencies of the title compound were obtained theoretically by DFT/B3LYP calculations employing the standard 6-311+G(d,p) and 6-311++G(d,p) basis set for optimized geometry and were compared with Fourier transform infrared spectrum (FTIR) in the region of 4000-400 cm(-1) and with Fourier transform Raman spectrum in the region of 4000-100 cm(-1). Complete vibrational assignments, analysis and correlation of the fundamental modes for the title compound were carried out. The vibrational harmonic frequencies were scaled using scale factor, yielding a good agreement between the experimentally recorded and the theoretically calculated values. The study is extended to calculate the HOMO-LUMO energy gap, NBO, mapped molecular electrostatic potential (MEP) surfaces, polarizability, Mulliken charges and thermodynamic properties of the title compound. PMID:24785089

  11. Thermodynamic Approach to Enhanced Dispersion and Physical Properties in a Carbon Nanotube/Polypeptide Nanocomposite

    NASA Technical Reports Server (NTRS)

    Lovell, Conrad S.; Wise, Kristopher E.; Kim, Jae-Woo; Lillehei, Peter T.; Harrison, Joycelyn S.; Park, Cheol

    2009-01-01

    A high molecular weight synthetic polypeptide has been designed which exhibits favorable interactions with single wall carbon nanotubes (SWCNTs). The enthalpic and entropic penalties of mixing between these two molecules are reduced due to the polypeptide's aromatic sidechains and helical secondary structure, respectively. These enhanced interactions result in a well dispersed SWCNT/Poly (L-Leucine-ran-L-Phenylalanine) nanocomposite with enhanced mechanical and electrical properties using only shear mixing and sonication. At 0.5 wt% loading of SWCNT filler, the nanocomposite exhibits simultaneous increases in the Young's modulus, failure strain, and toughness of 8%, 120%, and 144%, respectively. At one kHz, the same nanotube loading level also enhances the dielectric constant from 2.95 to 22.81, while increasing the conductivity by four orders of magnitude.

  12. Anharmonicity, mechanical instability, and thermodynamic properties of the Cr-Re ?-phase

    SciTech Connect

    Palumbo, Mauro Fries, Suzana G.; Pasturel, Alain; Alfè, Dario

    2014-04-14

    Using density-functional theory in combination with the direct force method and molecular dynamics we investigate the vibrational properties of a binary Cr-Re ?-phase. In the harmonic approximation, we have computed phonon dispersion curves and density of states, evidencing structural and chemical effects. We found that the ?-phase is mechanically unstable in some configurations, for example, when all crystallographic sites are occupied by Re atoms. By using a molecular-dynamics-based method, we have analysed the anharmonicity in the system and found negligible effects (?0.5 kJ/mol) on the Helmholtz energy of the binary Cr-Re ?-phase up to 2000 K (?0.8T{sub m}). Finally, we show that the vibrational contribution has significant consequences on the disordering of the ?-phase at high temperature.

  13. Correlation corrections to the thermodynamic properties of spin asymmetric QGP matter

    E-print Network

    Pal, Kausik

    2014-01-01

    We calculate the free energy, entropy and pressure of QGP at finite temperature and density with a given fraction of spin-up and spin-down quarks using MIT bag model with corrections upto ${\\cal O} (g^4 \\ln g^2)$. The expressions for the specific heat, spin susceptibility in terms of Fermi momentum and temperature are derived. The effects of interaction between the quarks on the properties of the QGP phase are also investigated. Within our phenomenological model, we estimate the transition temperature $T_c$ by constructing the phase boundary between the hadronic phase to the QGP phase. Finally, we compute the equation of state of QGP and see the effects of temperature and density on the equation of state.

  14. FP-LAPW investigation of the structural, electronic and thermodynamic properties of Al3Ta compound

    NASA Astrophysics Data System (ADS)

    Boulechfar, R.; Meradji, H.; Chouahda, Z.; Ghemid, S.; Drablia, S.; Khenata, R.

    2015-09-01

    The phase stability and electronic properties in Al3Ta compound are studied using the FP-LAPW method. In this approach, the generalized gradient approximation (GGA) is used for the exchange-correlation potential calculation. The total energy calculations show that the D022 structure is more stable than that of D023 and L12. The densities of states exhibit a pseudo gap near the Fermi level for all considered structures. By analyzing the electronic charge density we find a build-up of electrons in the interstitial region, and the bonds are directed from the Ta atoms to the Al atoms, which is the characteristic of covalent bonding. The temperature and pressure effects on the structural parameters, Debye temperature, Grüneisen parameter, heat capacities (Cv, Cp) and thermal expansion are predicted through the quasi-harmonic Debye model.

  15. Polymer chain properties and thermodynamic stability in oriented-platelet nanocomposites.

    PubMed

    Termonia, Yves

    2013-07-01

    We present a Monte Carlo study of the conformational properties of polymer chains in platelet nanocomposites. We find that high platelet orientation leads to an increase in chain confinement and to a substantial decrease in polymer entropy. The latter may be responsible for the observed aging of these systems in which the platelets gradually lose their orientation with time. As a test of our entropy-driven hypothesis, we suggest that aging could be substantially slowed down by the addition of small spherical nanoparticles. Using a generalized Stokes-Einstein relation, a calculation of the thermal random motion of the platelets predicts a fivefold increase in shear modulus during aging, in agreement with experimental observation on compatibilized layered silicate nanocomposites. PMID:23944482

  16. Polymer chain properties and thermodynamic stability in oriented-platelet nanocomposites

    NASA Astrophysics Data System (ADS)

    Termonia, Yves

    2013-07-01

    We present a Monte Carlo study of the conformational properties of polymer chains in platelet nanocomposites. We find that high platelet orientation leads to an increase in chain confinement and to a substantial decrease in polymer entropy. The latter may be responsible for the observed aging of these systems in which the platelets gradually lose their orientation with time. As a test of our entropy-driven hypothesis, we suggest that aging could be substantially slowed down by the addition of small spherical nanoparticles. Using a generalized Stokes-Einstein relation, a calculation of the thermal random motion of the platelets predicts a fivefold increase in shear modulus during aging, in agreement with experimental observation on compatibilized layered silicate nanocomposites.

  17. The Extended Thermodynamic Properties of a topological Taub-NUT/Bolt-AdS spaces

    E-print Network

    Lee, Chong Oh

    2015-01-01

    We consider the extended thermodynamic quantities of higher dimensional topological Taub-NUT/Bolt-AdS black holes with a cosmological constant treated as a pressure and find their general form for arbitrary dimensions and the thermodynamics of these configurations is argued to some extent. In particular by introducing Gibbs free energy, it is found out to be a new thermodynamically stable region of these black holes. At an equilibrium condition we find an entropy of a NUT solution, volume, and latent heat are negative where the Clapeyron equation is satisfied for these thermodynamic quantities. These negative volume and entropy may be interpreted as that the environment applies work to the system in the process of the Taub-NUT-AdS black hole formation, and such negative latent heat may indicate a net release of latent energy back into the environment because of evaporating of the system. Intriguingly, we also find that like the AdS black hole case, Taub-Bolt-AdS black hole with two phases (phase of small and ...

  18. Thermodynamic bounds and general properties of optimal efficiency and power in linear responses.

    PubMed

    Jiang, Jian-Hua

    2014-10-01

    We study the optimal exergy efficiency and power for thermodynamic systems with an Onsager-type "current-force" relationship describing the linear response to external influences. We derive, in analytic forms, the maximum efficiency and optimal efficiency for maximum power for a thermodynamic machine described by a N×N symmetric Onsager matrix with arbitrary integer N. The figure of merit is expressed in terms of the largest eigenvalue of the "coupling matrix" which is solely determined by the Onsager matrix. Some simple but general relationships between the power and efficiency at the conditions for (i) maximum efficiency and (ii) optimal efficiency for maximum power are obtained. We show how the second law of thermodynamics bounds the optimal efficiency and the Onsager matrix and relate those bounds together. The maximum power theorem (Jacobi's Law) is generalized to all thermodynamic machines with a symmetric Onsager matrix in the linear-response regime. We also discuss systems with an asymmetric Onsager matrix (such as systems under magnetic field) for a particular situation and we show that the reversible limit of efficiency can be reached at finite output power. Cooperative effects are found to improve the figure of merit significantly in systems with multiply cross-correlated responses. Application to example systems demonstrates that the theory is helpful in guiding the search for high performance materials and structures in energy researches. PMID:25375457

  19. Einstein-Born-Infeld-Massive Gravity: adS-Black Hole Solutions and their Thermodynamical properties

    E-print Network

    Seyed Hossein Hendi; Behzad Eslam Panah; Shahram Panahiyan

    2015-08-12

    In this paper, we study massive gravity in the presence of Born-Infeld nonlinear electrodynamics. First, we obtain metric function related to this gravity and investigate the geometry of the solutions and find that there is an essential singularity at the origin ($r=0$). It will be shown that due to contribution of the massive part, the number, types and places of horizons may be changed. Next, we calculate the conserved and thermodynamic quantities and check the validation of the first law of thermodynamics. We also investigate thermal stability of these black holes in context of canonical ensemble. It will be shown that number, type and place of phase transition points are functions of different parameters which lead to dependency of stability conditions to these parameters. Also, it will be shown how the behavior of temperature is modified due to extension of massive gravity and strong nonlinearity parameter. Next, critical behavior of the system in extended phase space by considering cosmological constant as pressure is investigated. A study regarding neutral Einstein-massive gravity in context of extended phase space is done. Geometrical approach is employed to study the thermodynamical behavior of the system in context of heat capacity and extended phase space. It will be shown that GTs, heat capacity and extended phase space have consistent results. Finally, critical behavior of the system is investigated through use of another method. It will be pointed out that the results of this method is in agreement with other methods and follow the concepts of ordinary thermodynamics.

  20. Thermodynamic bounds and general properties of optimal efficiency and power in linear responses

    NASA Astrophysics Data System (ADS)

    Jiang, Jian-Hua

    2014-10-01

    We study the optimal exergy efficiency and power for thermodynamic systems with an Onsager-type "current-force" relationship describing the linear response to external influences. We derive, in analytic forms, the maximum efficiency and optimal efficiency for maximum power for a thermodynamic machine described by a N ×N symmetric Onsager matrix with arbitrary integer N. The figure of merit is expressed in terms of the largest eigenvalue of the "coupling matrix" which is solely determined by the Onsager matrix. Some simple but general relationships between the power and efficiency at the conditions for (i) maximum efficiency and (ii) optimal efficiency for maximum power are obtained. We show how the second law of thermodynamics bounds the optimal efficiency and the Onsager matrix and relate those bounds together. The maximum power theorem (Jacobi's Law) is generalized to all thermodynamic machines with a symmetric Onsager matrix in the linear-response regime. We also discuss systems with an asymmetric Onsager matrix (such as systems under magnetic field) for a particular situation and we show that the reversible limit of efficiency can be reached at finite output power. Cooperative effects are found to improve the figure of merit significantly in systems with multiply cross-correlated responses. Application to example systems demonstrates that the theory is helpful in guiding the search for high performance materials and structures in energy researches.

  1. Computational method to predict thermodynamic, transport, and flow properties for the modified Langley 8-foot high-temperature tunnel

    NASA Technical Reports Server (NTRS)

    Venkateswaran, S.; Hunt, L. Roane; Prabhu, Ramadas K.

    1992-01-01

    The Langley 8 foot high temperature tunnel (8 ft HTT) is used to test components of hypersonic vehicles for aerothermal loads definition and structural component verification. The test medium of the 8 ft HTT is obtained by burning a mixture of methane and air under high pressure; the combustion products are expanded through an axisymmetric conical contoured nozzle to simulate atmospheric flight at Mach 7. This facility was modified to raise the oxygen content of the test medium to match that of air and to include Mach 4 and Mach 5 capabilities. These modifications will facilitate the testing of hypersonic air breathing propulsion systems for a wide range of flight conditions. A computational method to predict the thermodynamic, transport, and flow properties of the equilibrium chemically reacting oxygen enriched methane-air combustion products was implemented in a computer code. This code calculates the fuel, air, and oxygen mass flow rates and test section flow properties for Mach 7, 5, and 4 nozzle configurations for given combustor and mixer conditions. Salient features of the 8 ft HTT are described, and some of the predicted tunnel operational characteristics are presented in the carpet plots to assist users in preparing test plans.

  2. Magnetic, thermodynamic and transport properties at the first and second order magnetic phase transitions in Dy5Si3 compound

    NASA Astrophysics Data System (ADS)

    Falkowski, M.; Kowalczyk, A.; Toli?ski, T.

    2013-04-01

    We present extended studies including the dc and ac magnetic susceptibility, magnetization, specific heat, electrical resistivity and magnetoresistivity measurements for the Dy5Si3 compound with the hexagonal Mn5Si3-type structure. The results indicate that this compound orders antiferromagnetically below TN=137 K. The magnetic properties of Dy5Si3 are mainly governed by the presence of the magnetic moments of Dy3+ ions. In the paramagnetic range, the magnetic susceptibility follows the Curie-Weiss law with ?eff=10.57 ?B/Dy, which is very close to the theoretical value of 10.6 ?B. From the magnetometric, specific heat and transport data it has been found that below 50 K this compound reveals a non-collinear magnetic order, associated with a phase transition, probably of the first order type. On the basis of the thermodynamic approach, we report the magnetocaloric properties in the whole temperature range but concentrate mainly on the region around 50 K. The magnetocaloric effect was calculated in terms of the isothermal magnetic entropy change ?SM as well as the adiabatic temperature change ?Tad using the specific heat data. In spite of the only moderate ?SM values a significant relative cooling power has been observed.

  3. Prediction study on mechanical and thermodynamic properties of orthorhombic Mg2SiO4 under high temperature

    NASA Astrophysics Data System (ADS)

    Zhou, Jianting; Zhang, Hong; Chen, Yue; Shong, Jun; Chen, Zhuo; Yang, Juan; Zheng, Zhou; Wang, Feng

    2014-09-01

    In this work, based on density functional theory and quasi-harmonic Debye model, mechanical and thermodynamic properties of orthorhombic Mg2SiO4 under high temperature are predicted. We found out that ?-Mg2SiO4 is mechanically stable under the condition from about 0 to 74 GPa. Results indicate that the main cause of mechanical instability is high pressure, and the effect caused by high temperature is small. C11, C22, C33, B and vp reduce with temperature just a little and increase with pressure obviously. Mg2SiO4 has excellent resistance to strong compression; however the resistance to shear is unsatisfactory. The Cv tends to the Petit and Dulong limit at high temperature under any pressure, and it is proportional to T3 at extremely low temperature. Pressure has an opposite effect on Cv than temperature. The suppressed effect on Cv caused by pressure is not obvious under low and very high temperature. Mg2SiO4 has three different thermal expansion coefficients (?) along a-, b- and c-axes, and ?aproperties are mainly due to Si-O covalent bonds and their directions.

  4. On the composition dependence of thermodynamic, dynamic and dielectric properties of water-methanol model mixtures. Molecular dynamics simulation results

    E-print Network

    E. Galicia-Andrés; H. Dominguez; L. Pusztai; O. Pizio

    2015-12-24

    We have investigated thermodynamic and dynamic properties as well as the dielectric constant of water-metha\\-nol model mixtures in the entire range of composition by using constant pressure molecular dynamics simulations at ambient conditions. The SPC/E and TIP4P/Ew water models are used in combination with the OPLS united atom modelling for methanol. Changes of the average number of hydrogen bonds between particles of different species and of the fractions of differently bonded molecules are put in correspondence with the behavior of excess mixing volume and enthalpy, of self-diffusion coefficients and rotational relaxation times. From the detailed analyses of the results obtained in this work, we conclude that an improvement of the description of an ample set of properties of water-methanol mixtures can possibly be reached, if a more sophisticated, carefully parameterized, e.g., all atom, model for methanol is used. Moreover, exploration of parametrization of the methanol force field, with simultaneous application of different combination rules for methanol-water cross interactions, is required.

  5. First principle study of elastic and thermodynamic properties of FeB{sub 4} under high pressure

    SciTech Connect

    Zhang, Xinyu E-mail: jiaqianqin@gmail.com Ning, Jinliang; Sun, Xiaowei; Li, Xinting; Ma, Mingzhen; Liu, Riping E-mail: jiaqianqin@gmail.com; Qin, Jiaqian E-mail: jiaqianqin@gmail.com

    2013-11-14

    The elastic properties, elastic anisotropy, and thermodynamic properties of the lately synthesized orthorhombic FeB{sub 4} at high pressures are investigated using first-principles density functional calculations. The calculated equilibrium parameters are in good agreement with the available experimental and theoretical data. The obtained normalized volume dependence of high pressure is consistent with the previous experimental data investigated using high-pressure synchrotron x-ray diffraction. The complete elastic tensors and crystal anisotropies of the FeB{sub 4} are also determined in the pressure range of 0–100?GPa. By the elastic stability criteria and vibrational frequencies, it is predicted that the orthorhombic FeB{sub 4} is stable up to 100 GPa. In addition, the calculated B/G ratio reveals that FeB{sub 4} possesses brittle nature in the range of pressure from 0 to 100?GPa. The calculated elastic anisotropic factors suggest that FeB{sub 4} is elastically anisotropic. By using quasi-harmonic Debye model, the compressibility, bulk modulus, the coefficient of thermal expansion, the heat capacity, and the Grüneisen parameter of FeB{sub 4} are successfully obtained in the present work.

  6. First-principles investigations on the phase stability, elastic and thermodynamic properties of Zr-Al alloys

    NASA Astrophysics Data System (ADS)

    Wang, Leini; Hou, Songjun; Liang, Dewei

    2015-06-01

    In this paper, we employ first-principles methods based on electronic density functional theory (DFT) to investigate the phase stability, elastic and thermodynamic properties of Zr-Al binary substitutional alloys which are Zr3Al, Zr2Al, ZrAl, ZrAl2 and ZrAl3. By analyzing the elastic constants and enthalpy of formation, those phases both satisfy the generalized stability criteria and the results show that ZrAl2 is the most stable. Due to high bulk modulus B, shear modulus G and Youngs modulus Y, ZrAl2 also possesses excellent mechanical properties. Moreover, it is expected that there will be covalent bonding between Zr and Al atom in ZrAl2 compound, which is confirmed by the electronic structure and the differences of charge density discussions. In the end, based on the calculated elastic modulus, the elastic wave velocity, Debye temperature ?D and specific heat CV are discussed. As a result, ZrAl3 possesses the highest Debye temperature and sound velocity, meaning a larger associated thermal conductivity and higher melting temperature.

  7. Size-dependent thermodynamic and electronic properties of individual nanometer-size supported gold clusters

    SciTech Connect

    Lin, M.E.; Ramachandra, A.; Andres, R.P.; Reifenberger, R.

    1991-12-31

    Field emission techniques devised to measure the melting temperature and electronic structure of individual, nanometer-size clusters supported on electrically conducting substrates are reviewed. Data on the size-dependent reduction in melting temperature of Au cluster are compared to existing thermodynamic descriptions and molecular dynamic calculations. Data on the electronic structure of an individual 1nm Au cluster are compared to the predictions of simple electron shell models for cluster electronic states.

  8. Molecular simulation of thermodynamic and transport properties for the H{sub 2}O+NaCl system

    SciTech Connect

    Orozco, Gustavo A.; Jiang, Hao; Panagiotopoulos, Athanassios Z.; Moultos, Othonas A.; Economou, Ioannis G.

    2014-12-21

    Molecular dynamics and Monte Carlo simulations have been carried out to obtain thermodynamic and transport properties of the binary mixture H{sub 2}O+NaCl at temperatures from T = 298 to 473 K. In particular, vapor pressures, liquid densities, viscosities, and vapor-liquid interfacial tensions have been obtained as functions of pressure and salt concentration. Several previously proposed fixed-point-charge models that include either Lennard-Jones (LJ) 12-6 or exponential-6 (Exp6) functional forms to describe non-Coulombic interactions were studied. In particular, for water we used the SPC and SPC/E (LJ) models in their rigid forms, a semiflexible version of the SPC/E (LJ) model, and the Errington-Panagiotopoulos Exp6 model; for NaCl, we used the Smith-Dang and Joung-Cheatham (LJ) parameterizations as well as the Tosi-Fumi (Exp6) model. While none of the model combinations are able to reproduce simultaneously all target properties, vapor pressures are well represented using the SPC plus Joung-Cheathem model combination, and all LJ models do well for the liquid density, with the semiflexible SPC/E plus Joung-Cheatham combination being the most accurate. For viscosities, the combination of rigid SPC/E plus Smith-Dang is the best alternative. For interfacial tensions, the combination of the semiflexible SPC/E plus Smith-Dang or Joung-Cheatham gives the best results. Inclusion of water flexibility improves the mixture densities and interfacial tensions, at the cost of larger deviations for the vapor pressures and viscosities. The Exp6 water plus Tosi-Fumi salt model combination was found to perform poorly for most of the properties of interest, in particular being unable to describe the experimental trend for the vapor pressure as a function of salt concentration.

  9. Measuring Thermodynamic Properties of Metals and Alloys With Knudsen Effusion Mass Spectrometry

    NASA Technical Reports Server (NTRS)

    Copland, Evan H.; Jacobson, Nathan S.

    2010-01-01

    This report reviews Knudsen effusion mass spectrometry (KEMS) as it relates to thermodynamic measurements of metals and alloys. First, general aspects are reviewed, with emphasis on the Knudsen-cell vapor source and molecular beam formation, and mass spectrometry issues germane to this type of instrument are discussed briefly. The relationship between the vapor pressure inside the effusion cell and the measured ion intensity is the key to KEMS and is derived in detail. Then common methods used to determine thermodynamic quantities with KEMS are discussed. Enthalpies of vaporization, the fundamental measurement, are determined from the variation of relative partial pressure with temperature using the second-law method or by calculating a free energy of formation and subtracting the entropy contribution using the third-law method. For single-cell KEMS instruments, measurements can be used to determine the partial Gibbs free energy if the sensitivity factor remains constant over multiple experiments. The ion-current ratio method and dimer-monomer method are also viable in some systems. For a multiple-cell KEMS instrument, activities are obtained by direct comparison with a suitable component reference state or a secondary standard. Internal checks for correct instrument operation and general procedural guidelines also are discussed. Finally, general comments are made about future directions in measuring alloy thermodynamics with KEMS.

  10. Hypothetical Thermodynamic Properties: Vapor Pressures and Vaporization Enthalpies of the Even n-Alkanes from C40 to C76 at T ) 298.15 K by

    E-print Network

    Chickos, James S.

    Hypothetical Thermodynamic Properties: Vapor Pressures and Vaporization Enthalpies of the Even n in combination with earlier work to evaluate the vaporization enthalpies and vapor pressures of these n-alkanes from T ) (298.15 to 540) K. The vapor pressure and vaporization enthalpy results obtained are compared

  11. Hypothetical Thermodynamic Properties: Vapor Pressures and Vaporization Enthalpies of the Even n-Alkanes from C78 to C92 at T ) 298.15 K by

    E-print Network

    Chickos, James S.

    Hypothetical Thermodynamic Properties: Vapor Pressures and Vaporization Enthalpies of the Even n and vapor pressures of the n-alkanes from T ) (298.15 to 540) K for heneicosane to dononacontane. The vapor pressure and vaporization enthalpy results obtained are compared with estimated data from Morgan's "PERT2

  12. Ab initio description of heterostructural alloys: Thermodynamic and structural properties of MgxZn1-xO and CdxZn1-xO

    E-print Network

    Schleife, André

    high temperatures, i.e., where the mixing entropy is sufficiently large; at lower temperaturesAb initio description of heterostructural alloys: Thermodynamic and structural properties of MgxZn1 received 4 May 2010; published 17 June 2010 Pseudobinary heterostructural alloys of ZnO with MgO or Cd

  13. Ab-initio aprroach to the electronic, structural, elastic, and finite-temperature thermodynamic properties of Ti2AX (A = Al or Ga and X = C or N)

    NASA Astrophysics Data System (ADS)

    Duong, Thien; Gibbons, Sean; Kinra, Rajeev; Arróyave, Raymundo

    2011-11-01

    In this work, the electronic, structural, elastic, and thermodynamic properties of Ti2AX MAX phases (A = Al or Ga, X = C or N) were investigated using density functional theory (DFT). It is shown that the calculations of the electronic, structural, and elastic properties of these structures, using local density approximation (LDA) and generalized gradient approximation (GGA) coupled with projected augmented-wave (PAW) pseudopotentials, agree well with experiments. A thermodynamic model, which considers the vibrational and electronic contributions to the total free energy of the system, was used to investigate the finite-temperature thermodynamic properties of Ti2AX. The vibrational contribution was calculated using the supercell method, whereas the electronic contribution resulted from one-dimensional integration of electronic density of states (DOSs). To verify the model, the specific heats of pure elements were calculated and compared to experimental data. The DFT-D2 technique was used to calculate the heat capacity of graphite, taking into account the van der Waals (vdW) effect. Good agreement between the calculations and experiments for the specific heats of graphite and other pure elements lends validity to the approach used. The calculated results for the specific heats of Ti2AlC and Ti2AlN match well with experimental data. These strengthen the results of specific heats of Ti2GaC and Ti2GaN as well as other calculated thermodynamic properties, including the energies of formation and thermal expansion coefficient.

  14. Calculation of the Standard Molal Thermodynamic Properties of Crystalline, Liquid, and Gas Organic Molecules at High Temperatures and Pressures

    NASA Astrophysics Data System (ADS)

    Helgeson, Harold C.; Owens, Christine E.; Knox, Annette M.; Richard, Laurent

    1998-03-01

    Calculation of the thermodynamic properties of organic solids, liquids, and gases at high temperatures and pressures is a requisite for characterizing hydrothermal metastable equilibrium states involving these species and quantifying the chemical affinities of irreversible reactions of organic molecules in natural gas, crude oil, kerogen, and coal with minerals and organic, inorganic, and biomolecular aqueous species in interstitial waters in sedimentary basins. To facilitate calculations of this kind, coefficients for the Parameters From Group Contributions (PFGC) equation of state have been compiled for a variety of groups in organic liquids and gases. In addition, molecular weights, critical temperatures and pressures, densities at 25°C and 1 bar, transition, melting, and boiling temperatures ( Tt,Pr, Tm,Pr, and Tv,Pr, respectively) and standard molal enthalpies of transition (? H° t,Pr), melting (? H° m,Pr), and vaporization (? H° v,Pr) of organic species at 1 bar ( Pr) have been tabulated, together with an internally consistent and comprehensive set of standard molal Gibbs free energies and enthalpies of formation from the elements in their stable state at 298.15 K ( Tr) and Pr (? G° f and ? H° f, respectively). The critical compilation also includes standard molal entropies ( S°) and volumes ( V°) at Tr and Pr, and standard molal heat capacity power function coefficients to compute the standard molal thermodynamic properties of organic solids, liquids, and gases as a function of temperature at 1 bar. These properties and coefficients have been tabulated for more than 500 crystalline solids, liquids, and gases, and those for many more can be computed from the equations of state group additivity algorithms. The crystalline species correspond to normal alkanes (C nH 2( n+1) ) with carbon numbers ( n, which is equal to the number of moles of carbon atoms in one mole of the species) ranging from 5 to 100, and 23 amino acids including glycine (C 2H 5NO 2), alanine (C 3H 7NO 2), valine (C 5H 11NO 2), leucine (C 6H 13NO 2), isoleucine (C 6H 13NO 2), aspartic acid (C 4H 7NO 4), glutamic acid (C 5H 9NO 4), asparagine (C 4H 8N 2O 3), glutamine (C 5H 10N 2O 3), proline (C 5H 9NO 2), phenylalanine (C 9H 11NO 2), tryptophan (C 11H 12N 2O 2), methionine (C 5H 11SNO 2), serine (C 3H 7NO 3), threonine (C 4H 9NO 3), cysteine (C 3H 7SNO 2), tyrosine (C 9H 11NO 3), lysine (C 6H 14N 2O 2), lysine:HCl (C 6H 15N 2O 2Cl), arginine (C 6H 14N 4O 2), arginine:HCl (C 6H 15N 4O 2Cl), histidine (C 6H 9N 3O 2), and histidine:HCl (C 6H 10N 3O 2Cl). The data for the latter compounds permit calculation of the standard molal thermodynamic properties of protein unfolding in biogeochemical processes (Helgeson et al 1998). The liquids and gases considered in the present study include normal alkanes (C nH 2( n+1) ) for carbon numbers ranging from 1 to 100, 2- and 3-methylalkanes (C nH 2( n+1) ) for 4 ? n ? 20 and 6 ? n ? 20, respectively, 2,3-dimethylpentane (C 7H 16), 4-methylheptane (C 8H 18), cycloalkanes (C nH 2 n) for 3 ? n ? 8, methylated benzenes (C nH 2( n-3) ) for 7 ? n ? 12, normal alkylbenzenes (C nH 2( n-3) ) for 6 ? n ? 20, normal 1-alcohols (C nH 2( n+1) O) for 1 ? n ? 20, ethylene glycol (C 2H 6O 2), glycerol (C 3H 8O 3), normal 1-alkanethiols (C nH 2( n+1) S) for 1 ? n ? 20, normal carboxylic acids (C nH 2 nO 2) for 2 ? n ? 20, and the following miscellaneous species: 2-thiabutane (C 3H 8S), thiophene (C 4H 4S), thiophenol (C 6H 6S), acetone (C 3H 6O), 2-butanone (C 4H 8O), ethyl acetate (C 4H 8O 2), pyridine (C 5H 5N), 3-methylpyridine (C 6H 7N), and quinoline (C 9H 7N). One additional liquid (2-methylthiacyclopentane (C 5H 10S)) was also considered along with crystalline and gaseous carbazole (C 12H 9N). The thermodynamic data and equations summarized below can be used together with the standard molal thermodynamic properties of high molecular weight organic compounds ( Richard and Helgeson 1995, Richard and Helgeson 1998a, Richard and Helgeson 1998b) and minerals, inorganic gases, and aqueo

  15. Thermodynamic properties of diosgenin determined by oxygen-bomb calorimetry and DSC

    NASA Astrophysics Data System (ADS)

    Zhao, Ming-Rui; Wang, Hong-Jie; Wang, Shu-Yu; Yue, Xiao-Xin

    2014-12-01

    The combustion enthalpy of diosgenin was determined by oxygen-bomb calorimetry. The standard mole combustion enthalpy and the standard mole formation enthalpy have been calculated to be -16098.68 and -528.52 kJ mol-1, respectively. Fusion enthalpy and melting temperature for diosgenin were also measured to be -34.43 kJ mol-1 and 212.33°C, respectively, according to differential scanning calorimetry (DSC) data. These studies can provide useful thermodynamic data for this compound.

  16. Melting and thermodynamic properties of pyrope (Mg3Al2Si3O12)

    USGS Publications Warehouse

    Tequi, C.; Robie, R.A.; Hemingway, B.S.; Neuville, D.R.; Richet, P.

    1991-01-01

    The heat capacity of Mg3Al2Si3O12 glass has been measured from 10 to 1000 K by adiabatic and differential scanning calorimetry. The heat capacity of crystalline pyrope has been determined from drop-calorimetry measurements between 820 and 1300 K. From these and previously published results a consistent set of thermodynamic data is presented for pyrope and Mg3Al2Si3O12 glass and liquid for the interval 0-2000 K. The enthalpy of fusion at 1570 ?? 30 K, the metastable congruent 1-bar melting point, is 241 ?? 12 kJ/mol. ?? 1991.

  17. Thermodynamic Properties of Nitrogen Including Liquid and Vapor Phases from 63K to 2000K with Pressures to 10,000 Bar

    NASA Technical Reports Server (NTRS)

    Jacobsen, Richard T.; Stewart, Richard B.

    1973-01-01

    Tables of thermodynamic properties of nitrogen are presented for the liquid and vapor phases for temperatures from the freezing line to 2000K and pressures to 10,000 bar. The tables include values of density, internal energy, enthalpy, entropy, isochoric heat capacity, isobaric heat capacity velocity of sound, the isotherm derivative, and the isochor derivative. The thermodynamic property tables are based on an equation of state, P=P (p,T), which accurately represents liquid and gaseous nitrogen for the range of pressures and temperatures covered by the tables. Comparisons of property values calculated from the equation of state with measured values for P-p-T, heat capacity, enthalpy, latent heat, and velocity of sound are included to illustrate the agreement between the experimental data and the tables of properties presented here. The coefficients of the equation of state were determined by a weighted least squares fit to selected P-p-T data and, simultaneously, to isochoric heat capacity data determined by corresponding states analysis from oxygen data, and to data which define the phase equilibrium criteria for the saturated liquid and the saturated vapor. The vapor pressure equation, melting curve equation, and an equation to represent the ideal gas heat capacity are also presented. Estimates of the accuracy of the equation of state, the vapor pressure equation, and the ideal gas heat capacity equation are given. The equation of state, derivatives of the equation, and the integral functions for calculating derived thermodynamic properties are included.

  18. BAND STRUCTURE, HARDNESS, THERMODYNAMIC AND OPTICAL PROPERTIES OF SUPERCONDUCTING Nb2AsC, Nb2InC AND Mo2GaC

    NASA Astrophysics Data System (ADS)

    Hadi, M. A.; Ali, M. S.; Naqib, S. H.; Islam, A. K. M. A.

    2013-06-01

    First-principles investigation of the geometry, electronic band structure, Vickers hardness, thermodynamic and optical properties of three superconducting MAX compounds Nb2AsC, Nb2InC and Mo2GaC have been carried out by the plane-wave pseudopotential method based on density functional theory (DFT) implemented in the CASTEP code. The theoretical Vickers hardness has been studied by means of Mulliken bond population analysis and electronic densities of states. The thermodynamic properties such as the temperature and pressure dependent bulk modulus, Debye temperature, specific heats and thermal expansion coefficient of the three 211 MAX phases are derived from the quasi-harmonic Debye model with phononic effect for the first time. Furthermore, all the optical properties are determined and analyzed for the first time for two different polarization directions. The theoretical findings are compared with relevant experiments (where available) and the various implications are discussed in details.

  19. Interpreting equilibrium-conductivity and conductivity-relaxation measurements to establish thermodynamic and transport properties for multiple charged defect conducting ceramics.

    PubMed

    Zhu, Huayang; Ricote, Sandrine; Coors, W Grover; Kee, Robert J

    2015-10-10

    A model-based interpretation of measured equilibrium conductivity and conductivity relaxation is developed to establish thermodynamic, transport, and kinetics parameters for multiple charged defect conducting (MCDC) ceramic materials. The present study focuses on 10% yttrium-doped barium zirconate (BZY10). In principle, using the Nernst-Einstein relationship, equilibrium conductivity measurements are sufficient to establish thermodynamic and transport properties. However, in practice it is difficult to establish unique sets of properties using equilibrium conductivity alone. Combining equilibrium and conductivity-relaxation measurements serves to significantly improve the quantitative fidelity of the derived material properties. The models are developed using a Nernst-Planck-Poisson (NPP) formulation, which enables the quantitative representation of conductivity relaxations caused by very large changes in oxygen partial pressure. PMID:26230364

  20. Effects of Vacancy Cluster Defects on Electrical and Thermodynamic Properties of Silicon Crystals

    PubMed Central

    Huang, Pei-Hsing; Lu, Chi-Ming

    2014-01-01

    A first-principle plane-wave pseudopotential method based on the density function theory (DFT) was employed to investigate the effects of vacancy cluster (VC) defects on the band structure and thermoelectric properties of silicon (Si) crystals. Simulation results showed that various VC defects changed the energy band and localized electron density distribution of Si crystals and caused the band gap to decrease with increasing VC size. The results can be ascribed to the formation of a defect level produced by the dangling bonds, floating bonds, or high-strain atoms surrounding the VC defects. The appearance of imaginary frequencies in the phonon spectrum of defective Si crystals indicates that the defect-region structure is dynamically unstable and demonstrates phase changes. The phonon dispersion relation and phonon density of state were also investigated using density functional perturbation theory. The obtained Debye temperature (?D) for a perfect Si crystal had a minimum value of 448?K at T = 42?K and a maximum value of 671?K at the high-temperature limit, which is consistent with the experimental results reported by Flubacher. Moreover, the Debye temperature decreased with increases in the VC size. VC defects had minimal effects on the heat capacity (Cv) value when temperatures were below 150?K. As the temperature was higher than 150?K, the heat capacity gradually increased with increasing temperature until it achieved a constant value of 11.8?cal/cell·K. The heat capacity significantly decreased as the VC size increased. For a 2 × 2 × 2 superlattice Si crystal containing a hexagonal ring VC (HRVC10), the heat capacity decreased by approximately 17%. PMID:24526923

  1. A Thermodynamic Investigation of the Redox Properties of Ceria-Titania Mixed Oxides

    SciTech Connect

    Zhou,G.; Hanson, J.; Gorte, R.

    2008-01-01

    Ceria-titania solutions with compositions of Ce0.9Ti0.1O2 and Ce0.8Ti0.2O2 were prepared by the citric-acid (Pechini) method and characterized using X-ray diffraction (XRD) for structure, coulometric titration for redox thermodynamics, and water-gas-shift (WGS) reaction rates. Following calcination at 973 K, XRD suggests that the mixed oxides exist as single phase, fluorite structures, although there was no significant change in the lattice parameter compared to pure ceria. The mixed oxides are shown to be significantly more reducible than bulk ceria, with enthalpies for re-oxidation being approximately -500 kJ/mol O2, compared to -760 kJ/mol O2 for bulk ceria. However, WGS rates over 1 wt% Pd supported on ceria, Ce0.8Ti0.2O2, and Ce0.8Zr0.2O2 were nearly the same. For calcination at 1323 K, the mixed oxides separated into ceria and titania phases, as indicated by both the XRD and thermodynamic results.

  2. A thermodynamic approach to model the caloric properties of semicrystalline polymers

    NASA Astrophysics Data System (ADS)

    Lion, Alexander; Johlitz, Michael

    2015-02-01

    It is well known that the crystallisation and melting behaviour of semicrystalline polymers depends in a pronounced manner on the temperature history. If the polymer is in the liquid state above the melting point, and the temperature is reduced to a level below the glass transition, the final degree of crystallinity, the amount of the rigid amorphous phase and the configurational state of the mobile amorphous phase strongly depend on the cooling rate. If the temperature is increased afterwards, the extents of cold crystallisation and melting are functions of the heating rate. Since crystalline and amorphous phases exhibit different densities, the specific volume depends also on the temperature history. In this article, a thermodynamically based phenomenological approach is developed which allows for the constitutive representation of these phenomena in the time domain. The degree of crystallinity and the configuration of the amorphous phase are represented by two internal state variables whose evolution equations are formulated under consideration of the second law of thermodynamics. The model for the specific Gibbs free energy takes the chemical potentials of the different phases and the mixture entropy into account. For simplification, it is assumed that the amount of the rigid amorphous phase is proportional to the degree of crystallinity. An essential outcome of the model is an equation in closed form for the equilibrium degree of crystallinity in dependence on pressure and temperature. Numerical simulations demonstrate that the process dependences of crystallisation and melting under consideration of the glass transition are represented.

  3. Thermodynamic properties of uranium in liquid gallium, indium and their alloys

    NASA Astrophysics Data System (ADS)

    Volkovich, V. A.; Maltsev, D. S.; Yamshchikov, L. F.; Osipenko, A. G.

    2015-09-01

    Activity, activity coefficients and solubility of uranium was determined in gallium, indium and gallium-indium alloys containing 21.8 (eutectic), 40 and 70 wt.% In. Activity was measured at 573-1073 K employing the electromotive force method, and solubility between room temperature (or the alloy melting point) and 1073 K employing direct physical measurements. Activity coefficients were obtained from the difference of experimentally determined temperature dependencies of uranium activity and solubility. Intermetallic compounds formed in the respective alloys were characterized using X-ray diffraction. Partial and excess thermodynamic functions of uranium in the studied alloys were calculated. Liquidus lines in U-Ga and U-In phase diagrams from the side rich in gallium or indium are proposed.

  4. Acid-catalyzed furfurly alcohol polymerization : characterizations of molecular structure and thermodynamic properties.

    SciTech Connect

    Kim, T.; Assary, R. S.; Marshall, C. L.; Gosztola, D. J.; Curtiss, L. A.; Stair, P. C.

    2011-01-01

    The liquid-phase polymerization of furfuryl alcohol catalyzed by sulfuric acid catalysts and the identities of molecular intermediates were investigated by using Raman spectroscopy and density functional theory calculation. At room temperature, with an acid catalyst, a vigorous furfuryl alcohol polymerization reaction was observed, whereas even at a high water concentration, furfuryl alcohol was very stable in the absence of an acid catalyst. Theoretical studies were carried out to investigate the thermodynamics of protonation of furfuryl alcohol, initiation of polymerization, and formation of conjugated dienes and diketonic species by using the B3LYP level of theory. A strong aliphatic C=C band observed in the calculated and measured Raman spectra provided crucial evidence to understand the polymerization reaction mechanism. It is confirmed that the formation of a conjugated diene structure rather than a diketone structure is involved in the furfuryl alcohol polymerization reaction.

  5. Impact of Aerosols and Atmospheric Thermodynamics on Cloud Properties within the Climate System

    NASA Technical Reports Server (NTRS)

    Matsui, Toshihisa; Masunaga, Hirohiko; Pielke, Roger, Sr.; Tao, Wei-Kuo

    2003-01-01

    A combination of cloud-top and columnar droplet sizes derived from the multi Tropical Rainfall Measurement Mission (TRMM) sensors reveals the sensitivity of the aerosols effect on cloud-precipitation process due to environmental vertical thermodynamic structure. First, the magnitude of aerosol indirect effect could be larger with the analysis of columnar droplet sizes than that derived from the cloud-top droplet sizes, since column-droplet size can account for the broader droplet spectra in the cloud layers. Second, a combination of cloud- top and columnar droplet sizes reveals that the warm rain process is prevented regardless of the aerosols concentration under a high static stability such as when a strong temperature inversion exists, while a high aerosol concentration suppresses the warm rain formulation under a low static stability.

  6. The role of vibrations in thermodynamic properties of Cu-Ni alloys

    NASA Astrophysics Data System (ADS)

    Onat, Berk; Durukano?lu, Sondan

    2014-11-01

    We report results of a systematic study for vibrational thermodynamic functions of Cu-Ni alloys, in the harmonic approximation, using interaction potentials based on the embedded atom method with improved optimization techniques. The vibrational density of states of the systems is calculated using real space Green's function method. From an investigation of local force fields we found that increasing Ni concentration in the alloy substantially stiffens the force experienced by Cu atoms compared to that of Ni atoms. Our calculations also reveal that vibrational entropy change between ordered and disordered crystals of Cu-Ni is negligible. However, the mixing entropy of the phonons and electronic states is found to be negative and favors un-mixing, and thus contributes to the miscibility gap.

  7. Simulating Cellulose Structure, Properties, Thermodynamics, Synthesis, and Deconstruction with Atomistic and Coarse-Grain Models

    SciTech Connect

    Crowley, M. F.; Matthews, J.; Beckham, G.; Bomble, Y.; Hynninen, A. P.; Ciesielski, P. F.

    2012-01-01

    Cellulose is still a mysterious polymer in many ways: structure of microfibrils, thermodynamics of synthesis and degradation, and interactions with other plant cell wall components. Our aim is to uncover the details and mechanisms of cellulose digestion and synthesis. We report the details of the structure of cellulose 1-beta under several temperature conditions and report here the results of these studies and connections to experimental measurements and the measurement in-silico the free energy of decrystallization of several morphologies of cellulose. In spatially large modeling, we show the most recent work of mapping atomistic and coarse-grain models into tomographic images of cellulose and extreme coarse-grain modeling of interactions of large cellulase complexes with microfibrils. We discuss the difficulties of modeling cellulose and suggest future work both experimental and theoretical to increase our understanding of cellulose and our ability to use it as a raw material for fuels and materials.

  8. Thermodynamics and structural properties of a confined HP protein determined by Wang-Landau simulation

    SciTech Connect

    Pattanasiri, Busara; Li, Ying Wai; Landau, David P; Wuest, Thomas; Triampo, Wannapong

    2013-01-01

    We used Wang-Landau sampling with inventive Monte Carlo moves to study the influence of surface characteristics on physical behavior of a hydrophobic-polar (HP) lattice protein model confined between two attractive surfaces. Three types of surfaces, namely, surfaces that attract: (a) all monomers; (b) only P monomers; or (c) only H monomers, have been considered. After obtaining the densities of states, we then found the thermodynamic and structural quantities, such as specific heat, number of surface contacts, and number of hydrophobic interaction pairs. A few conformational transitions , e.g., debridging process and hydrophobic core formation, can be identified based on an analysis of these quantities. Depending on the surface types, these transitions take place at different temperatures, while the ground state configurations show structural variations. These scenarios are confirmed by snapshots of typical states of the systems.

  9. The effect of jasplakinolide on the thermodynamic properties of ADP.BeFx bound actin filaments

    PubMed Central

    Kardos, Roland; Vig, Andrea; Orbán, József; Hild, Gábor; Nyitrai, Miklós; L?rinczy, Dénes

    2010-01-01

    The effect of BeFx and a natural toxin (jasplakinolide) was examined on the thermal stability of actin filaments by using differential scanning calorimetry. The phosphate analogue beryllium fluoride shifted the melting temperature of actin filaments (67.4 °C) to 83.7 °C indicating that the filaments were thermodynamically more stable in their complex with ADP.BeFx. A similar tendency was observed when the jasplakinolide was used in the absence of BeFx. When both the ADP.BeFx and the jasplakinolide bound to the actin filaments their collective effect was similar to that observed with ADP.BeFx or jasplakinolide alone. These results suggested that ADP.BeFx and jasplakinolide probably stabilize the actin filaments by similar molecular mechanisms. PMID:20543906

  10. Acid-catalyzed Furfuryl Alcohol Polymerization: Characterizations of Molecular Structure and Thermodynamic Properties

    SciTech Connect

    Kim, Taejin; Assary, Rajeev A.; Marshall, Christopher L.; Gosztola, David J.; Curtiss, Larry A.; Stair, Peter C.

    2011-07-22

    The liquid-phase polymerization of furfuryl alcohol catalyzed by sulfuric acid catalysts and the identities of molecular intermediates were investigated by using Raman spectroscopy and density functional theory calculation. At room temperature, with an acid catalyst, a vigorous furfuryl alcohol polymerization reaction was observed, whereas even at a high water concentration, furfuryl alcohol was very stable in the absence of an acid catalyst. Theoretical studies were carried out to investigate the thermodynamics of protonation of furfuryl alcohol, initiation of polymerization, and formation of conjugated dienes and diketonic species by using the B3LYP level of theory. A strong aliphatic C=C band observed in the calculated and measured Raman spectra provided crucial evidence to understand the polymerization reaction mechanism. It is confirmed that the formation of a conjugated diene structure rather than a diketone structure is involved in the furfuryl alcohol polymerization reaction.

  11. Spectroscopic and thermodynamic properties of molecular hydrogen dissolved in water at pressures up to 200 MPa

    SciTech Connect

    Borysow, Jacek Rosso, Leonardo del; Celli, Milva; Ulivi, Lorenzo; Moraldi, Massimo

    2014-04-28

    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.

  12. EFFECT OF HEATING RATE ON THE THERMODYNAMIC PROPERTIES OF PULVERIZED COAL

    SciTech Connect

    Ramanathan Sampath

    1999-04-29

    This semi-annual technical progress report describes work performed under DOE Grant No. DE-FG22-96PC96224 during the period September 24, 1998 to March 23, 1999 which covers the fifth six months of the project. Devolatilization is an important initial step in virtually all commercial fossil fuel applications such as combustion, gasification, and liquefaction. Characterization of the temperature history of pulverized coal particles under high heating rates, representative of coal combustors, is critical to the understanding of devolatilization. During this reporting period, characterization experiments were continued from the previous reporting period and completed to a total of 28 single coal particles. These particles were caught in the electrodynamic balance and their volume, external surface area, mass, and density were measured. The same single particles were then heated bidirectionally with a pulsed (10 ms pulse width) Nd:YAG laser beams of equal intensity with heating rates (10{sup 4} - 10{sup 7} K/s) representative of coal combustors. The temporal power variation in the laser pulse was monitored for use in the heat transfer analysis by an ultra-fast fiber optic uv light transmitter included in the beam path and coupled to a silicon photodiode. Transient surface temperatures of the particles were measured using a single-color pyrometer. Dynamics of volatile evolution and particle swelling were recorded using well established time-resolved high-speed cinematography. Presently, extraction of devolatilization time-scales and temperature data at these time-scales running the high-speed films taken during the experiments employing a 16mm movie projector are in progress. Heat transfer analyses for the devolatilization time-scales, and temperature measurements (and hence an understanding of the effect of heating rates on coal thermal properties) are also in progress. Shipment of the donated heated grid system components from our industrial partner, United Technologies Research Center (UTRC), CT to CAU was complete during the previous reporting period. Testing of the heated grid system components at CAU and sensitivity analyses of the heated grid heat transfer calculations are also in progress.

  13. The zinc center influences the redox and thermodynamic properties of Escherichia coli thioredoxin 2.

    PubMed

    El Hajjaji, Hayat; Dumoulin, Mireille; Matagne, André; Colau, Didier; Roos, Goedele; Messens, Joris; Collet, Jean-Francois

    2009-02-13

    Thioredoxins are small, ubiquitous redox enzymes that reduce protein disulfide bonds by using a pair of cysteine residues present in a strictly conserved WCGPC catalytic motif. The Escherichia coli cytoplasm contains two thioredoxins, Trx1 and Trx2. Trx2 is special because it is induced under oxidative stress conditions and it has an additional N-terminal zinc-binding domain. We have determined the redox potential of Trx2, the pK(a) of the active site nucleophilic cysteine, as well as the stability of the oxidized and reduced form of the protein. Trx2 is more oxidizing than Trx1 (-221 mV versus -284 mV, respectively), which is in good agreement with the decreased value of the pK(a) of the nucleophilic cysteine (5.1 versus 7.1, respectively). The difference in stability between the oxidized and reduced forms of an oxidoreductase is the driving force to reduce substrate proteins. This difference is smaller for Trx2 (DeltaDeltaG degrees(H2O)=9 kJ/mol and DeltaT(m)=7. 4 degrees C) than for Trx1 (DeltaDeltaG degrees(H2O)=15 kJ/mol and DeltaT(m)=13 degrees C). Altogether, our data indicate that Trx2 is a significantly less reducing enzyme than Trx1, which suggests that Trx2 has a distinctive function. We disrupted the zinc center by mutating the four Zn(2+)-binding cysteines to serine. This mutant has a more reducing redox potential (-254 mV) and the pK(a) of its nucleophilic cysteine shifts from 5.1 to 7.1. The removal of Zn(2+) also decreases the overall stability of the reduced and oxidized forms by 3.2 kJ/mol and 5.8 kJ/mol, respectively. In conclusion, our data show that the Zn(2+)-center of Trx2 fine-tunes the properties of this unique thioredoxin. PMID:19073194

  14. Analbite - Sanidine Thermodynamic Mixing Properties: Highly Precise HF Solution Calorimetric Data Across A Twenty-Member Crystalline Solution Series

    NASA Astrophysics Data System (ADS)

    Hovis, G. L.

    2013-12-01

    Enthalpies of K-Na mixing for the analbite - sanidine feldspar series were investigated by Hovis (1988, J. Petrology) in the early 80's. That work was based on data at a limited number of compositions, owing to the large sample sizes required for HF solution calorimetric measurements at the time. Thermodynamic mixing properties for mineral series, especially those exhibiting compositionally asymmetric mixing quantities, are best defined when samples at a large number of compositions are utilized. Enabled by the small sample sizes now possible for HF solution calorimetric dissolutions (Hovis et al., 1998, Amer. Mineral.), we revisit feldspar thermodynamic properties, having synthesized an analbite - sanidine series consisting of samples at 20 compositions. Solution calorimetric experiments on these samples at 50 °C in 20.1 wt% HF under isoperibolic conditions have resulted in highly precise calorimetric data (standard deviation per sample averaging 0.06 % of the heat of solution). Although enthalpies of K-Na mixing based on the new data display some degree of compositional asymmetry, with a maximum value of 4.8 kJ/mol at a mole fraction potassium of 0.47, the distribution of enthalpy-of-mixing values remains nearly symmetric with respect to K content. This contrasts significantly with data for Al-Si ordered low albite - microcline crystalline solutions, reinvestigated via synthesis of a 21-member series, which show significantly higher mixing magnitudes and considerably greater asymmetry with respect to composition. The maximization of enthalpies of K-Na mixing at sodic compositions correlates well with the sodic critical compositions for both solvi. The lower mixing magnitudes for analbite - sanidine are consistent with the comparatively lower critical temperature of the analbite - sanidine solvus (e.g., Smith & Parsons, 1974, Mineral. Mag.) relative to that for low albite - microcline (Bachinski & Müller, 1971, J. Petrology). Entropies of K-Na mixing for analbite - sanidine have been calculated by combining present enthalpy data with Gibbs free energies of mixing derived from the earlier phase equilibrium study of Hovis et al. (1991, Amer. Mineral.). These may be compared with directly measured entropy data for analbite - sanidine based on the heat capacity measurements of Haselton et al. (1983, Amer. Mineral.). Thanks to the National Science Foundation for funding this research.

  15. Thermodynamic mixing properties and behavior of almandine-spessartine solid solutions

    NASA Astrophysics Data System (ADS)

    Dachs, Edgar; Geiger, Charles A.; Benisek, Artur; Grodzicki, Michael

    2014-01-01

    The heat capacity, Cp, of five solid-solution members of the almandine(Alm)-spessartine(Sps) binary, consisting of three synthetic polycrystalline and two natural single-crystal samples, was measured in the temperature range between 2 and 300 K using relaxation calorimetry and between 282 and 764 K using DSC methods. All garnets exhibit a ?-type heat-capacity anomaly at low temperatures resulting from a paramagnetic to antiferromagnetic phase transition. The temperature of the magnetic transition in Fe-rich garnets occurs between those of the two end-members (i.e. 9.2 K for almandine and 6.2 K for spessartine), but lies at lower values between 3.5 and 4.5 K for more Sps-rich compositions with XMngrt>0.5. The calorimetric entropy at 298 K shows mechanical-mixture behavior for Sps-rich garnets and a slight possible negative deviation from such behavior for Alm-rich compositions. At the 2? level all data are, however, consistent with ideal mixing behavior and the Margules entropy interaction parameter, WS,FeMngrt, is zero for the Alm-Sps binary. Thermodynamic analysis of published high P and T phase-equilibrium Fe-Mn exchange experiments between garnet and ilmenite shows that the excess Gibbs free energy of mixing, ?Gex, for Fe-Mn in garnet is positive and asymmetric towards spessartine. Margules enthalpy interaction parameters of WH,FeMngrt=4170±518 J/cation?mol and WH,MnFe=1221±588 J/cation?mol are derived giving a maximum of ?Gex?0.7 kJ/cation?mol at XMngrt?0.6. ?Hex obtained using autocorrelation analysis of published IR spectra of Alm-Sps solid solutions is in reasonable agreement with that derived from phase-equilibrium and calorimetry data. Previous diffraction and spectroscopic results on Alm-Sps garnets and quantum mechanical calculations made on almandine are used to interpret the macroscopic thermodynamic behavior from a microscopic basis. The relevance of the new garnet Fe-Mn mixing model for petrological calculations is demonstrated by incorporating it into the quaternary garnet mixing model of Berman (1990). Thus, better agreement for temperatures calculated using Fe-Mn garnet-ilmenite and Fe-Mg garnet-biotite geothermometry could be achieved. Temperatures calculated for Mn-poor and Mn-rich garnet-bearing assemblages, applying garnet-biotite thermometry, are in better agreement taking Fe-Mn mixing into account.

  16. Thermal equation of state and thermodynamic properties of molybdenum at high pressures

    NASA Astrophysics Data System (ADS)

    Litasov, Konstantin D.; Dorogokupets, Peter I.; Ohtani, Eiji; Fei, Yingwei; Shatskiy, Anton; Sharygin, Igor S.; Gavryushkin, Pavel N.; Rashchenko, Sergey V.; Seryotkin, Yury V.; Higo, Yiji; Funakoshi, Kenichi; Chanyshev, Artem D.; Lobanov, Sergey S.

    2013-03-01

    A comprehensive P-V-T dataset for bcc-Mo was obtained at pressures up to 31 GPa and temperatures from 300 to 1673 K using MgO and Au pressure calibrants. The thermodynamic analysis of these data was performed using high-temperature Birch-Murnaghan (HTBM) equations of state (EOS), Mie-Grüneisen-Debye (MGD) relation combined with the room-temperature Vinet EOS, and newly proposed Kunc-Einstein (KE) approach. The analysis of room-temperature compression data with the Vinet EOS yields V0 = 31.14 ± 0.02 Å3, KT = 260 ± 1 GPa, and KT' = 4.21 ± 0.05. The derived thermoelastic parameters for the HTBM include (?KT/?T)P = -0.019 ± 0.001 GPa/K and thermal expansion ? = a0 + a1T with a0 = 1.55 ( ± 0.05) × 10-5 K-1 and a1 = 0.68 ( ± 0.07) × 10-8 K-2. Fitting to the MGD relation yields ?0 = 2.03 ± 0.02 and q = 0.24 ± 0.02 with the Debye temperature (?0) fixed at 455-470 K. Two models are proposed for the KE EOS. The model 1 (Mo-1) is the best fit to our P-V-T data, whereas the second model (Mo-2) is derived by including the shock compression and other experimental measurements. Nevertheless, both models provide similar thermoelastic parameters. Parameters used on Mo-1 include two Einstein temperatures ?E10 = 366 K and ?E20 = 208 K; Grüneisen parameter at ambient condition ?0 = 1.64 and infinite compression ?? = 0.358 with ? = 0.323; and additional fitting parameters m = 0.195, e0 = 0.9 × 10-6 K-1, and g = 5.6. Fixed parameters include k = 2 in Kunc EOS, mE1 = mE2 = 1.5 in expression for Einstein temperature, and a0 = 0 (an intrinsic anharmonicity parameter). These parameters are the best representation of the experimental data for Mo and can be used for variety of thermodynamic calculations for Mo and Mo-containing systems including phase diagrams, chemical reactions, and electronic structure.

  17. Representative equations for the thermodynamic and transport properties of fluids near the gas-liquid critical point

    NASA Technical Reports Server (NTRS)

    Sengers, J. V.; Basu, R. S.; Sengers, J. M. H. L.

    1981-01-01

    A survey is presented of representative equations for various thermophysical properties of fluids in the critical region. Representative equations for the transport properties are included. Semi-empirical modifications of the theoretically predicted asymtotic critical behavior that yield simple and practical representations of the fluid properties in the critical region are emphasized.

  18. Moisture sorption isotherms and thermodynamic properties of mexican mennonite-style cheese.

    PubMed

    Martinez-Monteagudo, Sergio I; Salais-Fierro, Fabiola

    2014-10-01

    Moisture adsorption isotherms of fresh and ripened Mexican Mennonite-style cheese were investigated using the static gravimetric method at 4, 8, and 12 °C in a water activity range (aw) of 0.08-0.96. These isotherms were modeled using GAB, BET, Oswin and Halsey equations through weighed non-linear regression. All isotherms were sigmoid in shape, showing a type II BET isotherm, and the data were best described by GAB model. GAB model coefficients revealed that water adsorption by cheese matrix is a multilayer process characterized by molecules that are strongly bound in the monolayer and molecules that are slightly structured in a multilayer. Using the GAB model, it was possible to estimate thermodynamic functions (net isosteric heat, differential entropy, integral enthalpy and entropy, and enthalpy-entropy compensation) as function of moisture content. For both samples, the isosteric heat and differential entropy decreased with moisture content in exponential fashion. The integral enthalpy gradually decreased with increasing moisture content after reached a maximum value, while the integral entropy decreased with increasing moisture content after reached a minimum value. A linear compensation was found between integral enthalpy and entropy suggesting enthalpy controlled adsorption. Determination of moisture content and aw relationship yields to important information of controlling the ripening, drying and storage operations as well as understanding of the water state within a cheese matrix. PMID:25328178

  19. Free radical scavenger properties of ?-mangostin: thermodynamics and kinetics of HAT and RAF mechanisms.

    PubMed

    Martínez, Ana; Galano, Annia; Vargas, Rubicelia

    2011-11-01

    Mangosteen is a tropical fruit that presents beneficial effects on human health since it is rich in anthocyanins and xanthones, which are considered bioactive compounds that have been described as good free radical scavengers. One of its most active compounds is ?-mangostin. In this report, a theoretical study on the free radical scavenger capacity of ?-mangostin and its monoanion is analyzed using the density functional theory approximation. Two well-known reaction mechanisms are investigated: the hydrogen atom transfer (HAT) and the radical adduct formation (RAF). Two other mechanisms are also considered: sequential electron proton Transfer (SEPT) and proton coupled electron transfer (PCET). According to thermodynamics and kinetics, ?-mangostin and its deprotonated form are good free radical scavenger through the HAT mechanism, with the anionic (deprotonated) form being more reactive than the neutral one. Their capacity to scavenge OOH free radical is similar to that of carotenes, higher than that of allicin, much higher than that of melatonin and N-acetylcysteine amide, and about 15 times lower than that of 2-propenesulfenic acid. PMID:21936544

  20. Electrodynamic balance measurements of thermodynamic, kinetic, and optical aerosol properties inaccessible to bulk methods

    NASA Astrophysics Data System (ADS)

    Steimer, S. S.; Krieger, U. K.; Te, Y.-F.; Lienhard, D. M.; Huisman, A. J.; Luo, B. P.; Ammann, M.; Peter, T.

    2015-06-01

    Measurements of a single, levitated particle in an electrodynamic balance are an established tool for deriving thermodynamic and material data such as density, refractive index and activities of components of an aqueous solution under supersaturated conditions, where bulk measurements are not possible. The retrieval relies on combining mass-to-charge data and size data from light scattering. Here, we use a combination of low- and high-resolution Mie resonance spectroscopy to obtain radius data, enabling an accurate size determination not only when the particle is in equilibrium, but also when it is out of equilibrium due to kinetic limitation of mass transport. With the data measured under non-equilibrium conditions, it is possible to retrieve the water diffusivity. A challenge is that the radius retrieval by comparing measured light scattering with Mie theory requires the knowledge of refractive index as a function of concentration. Here, we show an iterative retrieval of refractive index and size for compounds for which data cannot be obtained in the bulk either due to lack of sufficient amounts of sample or limited solubility. We demonstrate the measurement strategy and the retrieval of water activity, density, refractive index and water diffusivity for aqueous shikimic acid. Water diffusivity in concentrated shikimic acid decreases by 6 orders of magnitude at 250 K compared to that at room temperature.

  1. Prediction of thermodynamic properties of coal derivatives. Final technical report, March 1, 1991--February 28, 1994

    SciTech Connect

    Donohue, M.D.

    1993-09-01

    We have developed new equations of state for pure-component chain molecules. The excellent performance of complicated theories, such as the Generalized Flory Dimer (GFD) theory can be mimicked by simpler equations, if assumptions for the shape parameters are made. We developed engineering correlations based on GFD theory, using local composition theory to take into account attractive forces. During this period, we compared methods for calculating repulsive and attractive contributions to equation of state against computer simulation data for hard and square-well chains, and against experimental data from the literature. We also have studied microstructure and local order in fluids that contain asymmetric molecules. We developed a thermodynamic model for polar compounds based on a site-site interaction approach. We have shown the equivalence of various classes of theories for hydrogen bonding, and used this equivalence to derive a multiple site model for water. In addition, simple cubic equations of state have been applied to calculate physical and chemical-reaction equilibria in nonideal systems. We measured infinite dilution activity coefficients using HPLC. We also measured high pressure vapor liquid equilibria of ternary and quaternary systems containing supercritical solvents. We used FT-IR spectroscopy to examine self-association of aliphatic alcohols due to hydrogen bonding, and to investigate the hydrogen bonding in polymer-solvent mixtures.

  2. The Interplay between Viscoelastic and Thermodynamic Properties Determines the Birefringence of F-Actin Gels

    PubMed Central

    Helfer, Emmanuèle; Panine, Pierre; Carlier, Marie-France; Davidson, Patrick

    2005-01-01

    F-actin gels of increasing concentrations (25–300 ?M) display in vitro a progressive onset of birefringence due to orientational ordering of actin filaments. At F-actin concentrations <100 ?M, this birefringence can be erased and restored at will by sonication and gentle flow, respectively. Hence, the orientational ordering does not result from a thermodynamic transition to a nematic phase but instead is due to mechanical stresses stored in the gels. In contrast, at F-actin concentrations ?100 ?M, gels display spontaneous birefringence recovery, at rest, which is the sign of true nematic ordering, in good agreement with statistical physics models of the isotropic/nematic transition. Well-aligned samples of F-actin gels could be produced and their small-angle x-ray scattering patterns are quite anisotropic. These patterns show no sign of filament positional short-range order and could be modeled by averaging the form factor with the Maier-Saupe nematic distribution function. The derived nematic order parameter S of the gels ranged from S = 0.7 at 300 ?M to S = 0.4 at 25 ?M. Both birefringence and small-angle x-ray scattering data indicate that, even in absence of cross-linking proteins, spontaneous cooperative alignment of actin filaments may arise in motile regions of living cells where F-actin concentrations can reach values of a few 100 ?M. PMID:15863487

  3. Vaporization of LaCrO{sub 3}: Partial and integral thermodynamic properties

    SciTech Connect

    Peck, D.H.; Miller, M.; Kobertz, D.; Nickel, H.; Hilpert, K.

    1996-12-01

    The vaporization of LaCrO{sub 3}(s) and samples of the composition LaCrO{sub 3} + La{sub 2}O{sub 3} was investigated in the temperature range of 1,887--2,333 K by Knudsen effusion mass spectrometry using Knudsen cells made of tungsten lined completely with iridium. The species Cr(g), CrO(g), CrO{sub 2}(g), and LaO(g) were identified in the vapor. Their partial pressures were determined by calibration with pure platinum solid. The thermodynamic activity of Cr{sub 2}O{sub 3}, a{sub Cr{sub 2}O{sub 3}}, in LaCrO{sub 3} for the Cr{sub 2}O{sub 3}-poor phase boundary of this phase was ln a{sub Cr{sub 2}O{sub 3}} = {minus}(17953/T) {minus} 0.485 (temperature T given in K) for the temperature range of the measurements with a probable overall error of {+-}13%. The following values and temperature dependence of {Delta}G{sub f,T}{sup o} resulted for the formation of LaCrO{sub 3}(s) according to the reaction 0.5Cr{sub 2}O{sub 3}(s) + 0.5La{sub 2}O{sub 3}(s) {r_arrow} LaCrO{sub 3}(s): {Delta}G{sub f,2100}{sup o} = {minus}78.9 {+-} 1.1 kJ/mol, {Delta}H{sub f,298}{sup o} = {minus}76.8 {+-} 5.2 kJ/mol, and {Delta}G{sub f,T}{sup o}(kJ/mol) = {minus}74.7 {minus} 0.00202T. Computations for the vaporization of LaCrO{sub 3} were conducted to show the volatility of this material in different atmospheres at high temperatures.

  4. Pressure-induced structural phase transition, elastic and thermodynamic properties of ReC under high pressure

    NASA Astrophysics Data System (ADS)

    Lei, Hui-Ru; Zhu, Jun; Hao, Yan-Jun; Zhang, Lin; Zhao, Yu-Xin; Zhan, Guo-Fu

    2015-10-01

    The pressure-induced structural phase transition of rhenium monocarbon (ReC) is investigated via the projector augmented wave (PAW) method with the generalized gradient approximation (GGA). Using the first-principles calculations, the equilibrium structural parameters of ReC in rocksalt (NaCl), cesium chloride (CsCl), zinc blende (ZB), wurtzite (WZ), nickel arsenide (NiAs) and tungsten carbide (WC) types are successfully obtained, and the results are well consistent with other theoretical data. It is firstly noted that WC-ReC translates into CsCl-ReC at 510.50 GPa by analyzing the enthalpy difference versus pressure. From the calculated elastic constants, the aggregate elastic modulus (B, G, E), the Poisson's ratio (?) and the Debye temperature ?D of WC-type are also derived. It is observed that all the data of WC-ReC obtained increase monotonically with increasing pressure. Meanwhile, the thermodynamic properties of WC-ReC under high temperature and high pressure are investigated applying nonempirical Debye model in the quasi-harmonic approximation.

  5. Thermodynamic properties and equation of state of fcc aluminum and bcc iron, derived from a lattice vibrational method

    NASA Astrophysics Data System (ADS)

    Jacobs, Michel H. G.; Schmid-Fetzer, Rainer

    2010-12-01

    We use a lattice vibrational technique to derive thermophysical and thermochemical properties of the pure elements aluminum and iron in pressure-temperature space. This semi-empirical technique is based on either the Mie-Grüneisen-Debye (MGD) approach or an extension of Kieffer's model to incorporate details of the phonon spectrum. It includes treatment of intrinsic anharmonicity, electronic effects based on the free electron gas model, and magnetic effects based on the Calphad approach. We show that Keane's equation of state for the static lattice is better suitable to represent thermodynamic data for aluminum from 1 bar to pressures in the multi-megabar region relative to Vinet's universal and the Birch-Murnaghan equation of state. It appears that the MGD and Mie-Grüneisen-Kieffer approach produce similar results, but that the last one better represents heat capacity below room temperature. For iron we show that the high temperature behavior of thermal expansivity can be explained within the Calphad approach by a pressure-dependent Curie temperature with a slope between -1 and 0 K/GPa.

  6. Sorption isotherms, thermodynamic properties and glass transition temperature of mucilage extracted from chia seeds (Salvia hispanica L.).

    PubMed

    Velázquez-Gutiérrez, Sandra Karina; Figueira, Ana Cristina; Rodríguez-Huezo, María Eva; Román-Guerrero, Angélica; Carrillo-Navas, Hector; Pérez-Alonso, César

    2015-05-01

    Freeze-dried chia mucilage adsorption isotherms were determined at 25, 35 and 40°C and fitted with the Guggenheim-Anderson-de Boer model. The integral thermodynamic properties (enthalpy and entropy) were estimated with the Clausius-Clapeyron equation. Pore radius of the mucilage, calculated with the Kelvin equation, varied from 0.87 to 6.44 nm in the temperature range studied. The point of maximum stability (minimum integral entropy) ranged between 7.56 and 7.63kg H2O per 100 kg of dry solids (d.s.) (water activity of 0.34-0.53). Enthalpy-entropy compensation for the mucilage showed two isokinetic temperatures: (i) one occurring at low moisture contents (0-7.56 kg H2O per 100 kg d.s.), controlled by changes in water entropy; and (ii) another happening in the moisture interval of 7.56-24 kg H2O per 100 kg d.s. and was enthalpy driven. The glass transition temperature Tg of the mucilage fluctuated between 42.93 and 57.93°C. PMID:25659716

  7. First-principles study of electronic, dynamical and thermodynamic properties of ?-Li4SiO4

    NASA Astrophysics Data System (ADS)

    Guan, Qiushi; Gao, Tao; Shen, Yanhong; Ma, Shenggui; Lu, Tiecheng; Chen, Xiaojun; Xiao, Chengjian; Long, Xinggui

    2015-07-01

    We have studied the structural, electronic and dynamic properties of ?-Li4SiO4 (lithium orthosilicate) using density functional theory (DFT) with the generalized gradient approximation (GGA). The crystal structure is fully relaxed. The electronic band structure and Density of States (DOS) calculations indicate that ?-Li4SiO4 is an insulator with an indirect band gap of 5.19 eV and it has a conduction band with the width of 5.92 eV and two valance bands with the width of 4.45 eV and 0.57 eV, respectively. In the partial DOS, Li and Si electronic densities increase more sharply than O atoms. Comparing with previous works, the phonon dispersion curves without negative frequencies are calculated along high symmetry points. By adding the Born effective charges in the phonon calculation, the LO-TO splittings are also calculated which indicate that ?-Li4SiO4 is polar and anisotropic. The optical modes of phonon frequencies at ? point are assigned as Raman and Infrared-active modes. Additionally, the thermodynamic functions (entropy, internal energy, Helmholtz free energies and constant-volume specific heats) were determined by using the phonon DOS. The calculated results may provide useful guidance of ?-Li4SiO4 for future experimental studies in some degree.

  8. Study of stability and thermodynamic properties of water-in-diesel nanoemulsion fuels with nano-Al additive

    NASA Astrophysics Data System (ADS)

    Mehta, Rakhi N.; More, Utkarsh; Malek, Naved; Chakraborty, Mousumi; Parikh, Parimal A.

    2015-11-01

    The present work addresses the formation of water-in-diesel (W/D) nanoemulsion by blending different percentages of water along with nano-Al additive in various propositions to enhance the combustion characteristics. The roles of various surfactants such as Sorbitan monooleate (Span 80), Triton X-100, Tetradecyltrimethylammonium bromide, and newly synthesized and characterized dicationic surfactants were discussed based upon their ability to stabilize the nanoemulsions. Surface active properties of the surfactants were determined by measuring their interfacial tension and subsequently by measuring the critical micelle concentration of the surfactants. Triton X-100 was found to be the most efficient surfactant for the current water-in-diesel nanoemulsion as it stabilized the suspensions for more than 8 h. Particle size analysis proved emulsion size to be in the order of nanometer, and zeta potential values were found to have neutral behavior at water-diesel interface. Experimental studies confirmed that that blends W/D [1 % (vol.) water] and W/DA [1 % (vol.) water, 0.1 % (wt.) nano-Al] were thermodynamically stable.

  9. Thermodynamic Properties of Sulfatian Apatite: Constraints on the Behavior of Sulfur in Calc-Alkaline Magmas

    NASA Astrophysics Data System (ADS)

    Core, D.; Essene, E. J.; Luhr, J. F.; Kesler, S. E.

    2004-12-01

    The Gibbs free energy of hydroxyellestadite [Ca10(SiO4)3(SO4)3(OH)2] was estimated using mineral equilibria applied to analyzed assemblages from the experimental charges of Luhr (1990). The apatite analyses of Peng et al. (1997) were used in conjunction with new analyses of the oxides and silicates in this study. An ideal mixing model was employed for apatite combined with mixing models from MELTS (Ghiorso & Sack, 1994) and Gibbs free energy data from Robie & Hemingway (1995) for the other crystalline phases. The resultant equation of the Gibbs free energy vs. T for hydroxyellestadite is as follows: DG°T(elem) = [2.817(T - 273) - 11831]/1000 kJ/mol, T in K. The calculated entropy for hydroxyellestadite is 1944 J/mol.K at 1073 K and 2151 J/mol.K at 1227 K. Independent estimates of the entropy of hydroxyellestadite obtained with the method of Robinson & Haas (1983) are within 5% of these values. The thermodynamic data on hydroxyellestadite were used to calculate the locus of the reactions: 2Ca10(SiO4)3(SO4)3(OH)2 + 7S2 + 21O2 = 20CaSO4 + 6SiO2 + 2H2O 6Ca10(SiO4)3(SO4)3(OH)2 + 102SiO2 + 20Fe3O4 = 60CaFeSi2O6 + 6H2O + 9S2 + 37O2 2Ca10(SiO4)3(SO4)3(OH)2 + 10Mg2Si2O6 + 14SiO2 = 20CaMgSi2O6 + 2H2O + 3S2 + 9O2 in fO2-fS2 space at fixed P-T. Application of these equilibria to apatite zoned in sulfate from oxidized granitoids reflects a drop in fS2 by more than 1 log unit during its growth. The zoning is interpreted to represent the removal of a magmatic vapor phase during crystallization of these plutons. Removal of sulfur from magmas by hydrothermal fluids is important to the ore-forming process and to the production of acid sulfate aerosols during eruption of oxidized magmas. Preservation of sulfatian apatite may yield data on the sulfidation states of ancient flood basalts such as the Deccan Traps of India and the Parana basalts of Brazil to address the environmental impact of these giant eruptions.

  10. A review of reaction rates and thermodynamic and transport properties for an 11-species air model for chemical and thermal nonequilibrium calculations to 30000 K

    NASA Technical Reports Server (NTRS)

    Gupta, Roop N.; Yos, Jerrold M.; Thompson, Richard A.; Lee, Kam-Pui

    1990-01-01

    Reaction rate coefficients and thermodynamic and transport properties are reviewed and supplemented for the 11-species air model which can be used for analyzing flows in chemical and thermal nonequilibrium up to temperatures of 3000 K. Such flows will likely occur around currently planned and future hypersonic vehicles. Guidelines for determining the state of the surrounding environment are provided. Curve fits are given for the various species properties for their efficient computation in flowfield codes. Approximate and more exact formulas are provided for computing the properties of partially ionized air mixtures in a high energy environment. Limitations of the approximate mixing laws are discussed for a mixture of ionized species. An electron number-density correction for the transport properties of the charged species is obtained. This correction has been generally ignored in the literature.

  11. Thermodynamic properties of scapolites at temperatures ranging from 10 K to 1000 K

    USGS Publications Warehouse

    Komada, N.; Moecher, D.P.; Westrum, E.F., Jr.; Hemingway, B.S.; Zolotov, M. Yu; Semenov, Y.V.; Khodakovsky, I.L.

    1996-01-01

    The heat capacities of five mineral samples from the scapolite solid-solution series, Na4Al3Si9O24Cl (marialite) to Ca4Al6Si6O24CO3 (meionite), were measured by the adiabatic method from T=8 K to T=350 K and by the differential scanning calorimetry (d.s.c.) method from T = 300 K to T = 1000 K. The meionite (Me) content in per cent {Me=100 Ca*/(Ca* + Na*)} (where the asterisk indicates that possible substituents are included) and molar heat capacity (Cp,m/R) at T=298.15 K for each sample is: Me28, 82.07; Me44, 82.09; Me55, 83.95; Me69, 85.80; Me88, 84.54. The standard molar entropies, {S,om(298.15 K)-Som(0 K)} R-1 (R=8.31451 J??K-1??mol-1), at T=298.15 K for the respective compositions are: 85.05??0.26, 83.78??0.50, 85.22??0.24, 85.76??0.21, and 84.17??0.59. The calculated standard molar entropies (as above) at T=298.15 K for the end-members marialite and meionite, and for an intermediate composition (mizzonite=Me75) are 84.85, 83.94 and 86.15, respectively. Values of the coefficients in the equation Cp,m/R = a + bT+ cT2 + dT-1/2 + eT-2 (valid from T = 300 K to T =1000 K) are: (Mex, a, b/K, c/K2, d/K-1/2, e/K-2 Me88), 315.580, -0.0795676, 1.52825.10-5, -3954.83, 1808460; Me69, 261.285, -0.0415017, 8.73053.10-7, -3028.28, 1083666; Me55, 232.236, -0.0352222, 6.49875.10-6, 2505.99, 601750; Me44, 276.696, -0.0756614, 2.39722.10-5, -3210.40, 1044363; Me28, 149.917, 0.0229399, -1.23180.10-5, 1208.87, -318470. Smoothed thermodynamic functions for the five samples are also presented. The enthalpies of solution for five natural scapolites were measured in 2PbO??B2O3 melts at T= 973 K by Calvet-type calorimetry. The values of ??solHom/R??K are: Me11, 32.14??0.7; Me28, 32.34??0.4; Me44, 33.66??0.8; Me69, 35.29??0.8; Me88, 32.87??0.3. The calculated enthalpies of formation for stoichiometric scapolites ??fHom/103??R??K at T= 298.15 K are: Me0, -1467.4??1.3; Me11, -1491.2??1.2; Me28, -1527.6??0.9; Me44, -1564.1??1.1; Me55, -1587.4??1.1; Me69, -1619.7??1.1; Me75, -1633.1??1.1; Me88, -1649.1??1.0; Me100, -1664??1.6. The heat capacity, the entropy, and the enthalpy of solution have maximal values near Me75 which may account in part for the relatively common occurrence of that composition in natural assemblages. Earlier measurements on leucite have been extended by the Komada/Westrum phonon dispersion model and corrected to end-member composition. ?? 1996 Academic Press Limited.

  12. A correlation between thermodynamic properties, thermal expansion and electrical resistivity of Ag-28% Cu nanopowders processed by the mechanical alloying route.

    PubMed

    Tanasescu, Speranta; Milea, Alexandru; Gingu, Oana; Maxim, Florentina; Hornoiu, Cristian; Preda, Silviu; Sima, Gabriela

    2015-11-14

    Thermodynamic properties, thermal expansion and electrical resistivity of the Ag-28% Cu nanopowders processed by the mechanical alloying route have been investigated in the temperature range from ambient to 1048 K. The thermodynamic properties represented by the relative enthalpy, the specific heat capacity, the relative entropy and the Gibbs energy function obtained from drop calorimetric measurements have been used to reveal the occurrence of the micro-relaxation process, as well as of the correlative effects of decomposition and growth processes. On the basis of the results, the parameters that favour stable nanostructured systems in Ag-28% Cu powders synthesized by the mechanical alloying route have been identified. The correlation of the energetic parameters with thermal expansion and electrical resistivity in mechanical alloyed nanocrystalline powders with the eutectic composition is discussed. PMID:25959221

  13. Study of the thermodynamic properties of CeO{sub 2} from ab initio calculations: The effect of phonon-phonon interaction

    SciTech Connect

    Niu, Zhen-Wei; Zeng, Zhao-Yi; Hu, Cui-E; Cai, Ling-Cang; Chen, Xiang-Rong

    2015-01-07

    The thermodynamic properties of CeO{sub 2} have been reevaluated by a simple but accurate scheme. All our calculations are based on the self-consistent ab initio lattice dynamical (SCAILD) method that goes beyond the quasiharmonic approximation. Through this method, the effects of phonon-phonon interactions are included. The obtained thermodynamic properties and phonon dispersion relations are in good agreement with experimental data when considering the correction of phonon-phonon interaction. We find that the correction of phonon-phonon interaction is equally important and should not be neglected. At last, by comparing with quasiharmonic approximation, the present scheme based on SCAILD method is probably more suitable for high temperature systems.

  14. Study of the thermodynamic properties of CeO2 from ab initio calculations: the effect of phonon-phonon interaction.

    PubMed

    Niu, Zhen-Wei; Zeng, Zhao-Yi; Hu, Cui-E; Cai, Ling-Cang; Chen, Xiang-Rong

    2015-01-01

    The thermodynamic properties of CeO2 have been reevaluated by a simple but accurate scheme. All our calculations are based on the self-consistent ab initio lattice dynamical (SCAILD) method that goes beyond the quasiharmonic approximation. Through this method, the effects of phonon-phonon interactions are included. The obtained thermodynamic properties and phonon dispersion relations are in good agreement with experimental data when considering the correction of phonon-phonon interaction. We find that the correction of phonon-phonon interaction is equally important and should not be neglected. At last, by comparing with quasiharmonic approximation, the present scheme based on SCAILD method is probably more suitable for high temperature systems. PMID:25573568

  15. Estimation and application of the thermodynamic properties of aqueous phenanthrene and isomers of methylphenanthrene at high temperature

    NASA Astrophysics Data System (ADS)

    Dick, Jeffrey M.; Evans, Katy A.; Holman, Alex I.; Jaraula, Caroline M. B.; Grice, Kliti

    2013-12-01

    Estimates of standard molal Gibbs energy (?Gf°) and enthalpy (?Hf°) of formation, entropy (S°), heat capacity (CP°) and volume (V°) at 25 °C and 1 bar of aqueous phenanthrene (P) and 1-, 2-, 3-, 4- and 9-methylphenanthrene (1-MP, 2-MP, 3-MP, 4-MP, 9-MP) were made by combining reported standard-state properties of the crystalline compounds, solubilities and enthalpies of phenanthrene and 1-MP, and relative Gibbs energies, enthalpies and entropies of aqueous MP isomers from published quantum chemical simulations. The calculated properties are consistent with greater stabilities of the ? isomers (2-MP and 3-MP) relative to the ? isomers (1-MP and 9-MP) at 25 °C. However, the metastable equilibrium values of the abundance ratios 2-MP/1-MP (MPR) and (2-MP + 3-MP)/(1-MP + 9-MP) (MPI-3) decrease with temperature, becoming <1 at ?375-455 °C. The thermodynamic model is consistent with observations of reversals of these organic maturity parameters at high temperature in hydrothermal and metamorphic settings. Application of the model to data reported for the Paleoproterozoic Here’s Your Chance (HYC) Pb-Zn-Ag ore deposit (McArthur River, Northern Territory, Australia) indicates a likely effect of high-temperature equilibration on reported values of MPR and MPI-3, but this finding is contingent on the location within the deposit. If metastable equilibrium holds, a third aromatic maturity ratio, 1.5 × (2-MP + 3-MP)/(P + 1-MP + 9-MP) (MPI-1), can be used as a proxy for oxidation potential. Values of logaH2aq determined from data reported for HYC and for a sequence of deeply buried source rocks are indicative of more reducing conditions at a given temperature than those inferred from data reported for two sets of samples exposed to contact or regional metamorphism. These results are limiting-case scenarios for the modeled systems that do not account for effects of non-ideal mixing or kinetics, or external sources or transport of the organic matter. Nevertheless, quantifying the temperature dependence of equilibrium constants of organic reactions enables the utilization of organic maturity parameters as relative geothermometers at temperatures higher than the nominal limits of the oil window.

  16. Modeling of anisotropic flow and thermodynamic properties of magnetic nanofluids induced by external magnetic field with varied imposing directions

    NASA Astrophysics Data System (ADS)

    Song, Dongxing; Jing, Dengwei; Luo, Bing; Geng, Jiafeng; Ren, Yuxun

    2015-07-01

    Magnetic field can enhance both thermal conductivity and Lorentz force resistance of the magnetic nanofluids (MNFs), in which the former is favored while the latter often leads to pressure drop of the flow. It is assumed that there would exist a balance between the magnetic field induced thermal conductivity and Lorentz force if one can appropriately adjust the angle of the imposing magnetic field with respect to the direction of the flow. In the present study, the effects of direction of magnetic field ( ?) on anisotropic thermodynamic properties of magnetic nanofluids in channel were studied. The effects of direction of magnetic field on thermal conductivity, Nusselt number, global total entropy generation, and other parameters, such as velocity, temperature, and concentration, have been discussed in detail. A greater ? can lead to a larger thermal conductivity normal to the walls of channel and a more uniform temperature field. However, the velocity of magnetic nanofluid tends to decrease. There is a threshold for magnetic intensity (B). When magnetic intensity becomes large than the threshold, its effect on thermal conductivity will tends to be constant. The effect of increase of ? is found to be similar to that of increasing Hartmann number ( H a ) and both can lead to augment of Lorentz resistance force along flow direction. With the increases of ? and H a , both heat transfer efficiency (Nu) and global total entropy generation ( ST ) increase. Here, ST indicates the extent of loss of useful work due to the irreversibility of the process. A comprehensive utility index, Iu , is defined for evaluation of the performance of a practical heat transfer system employing MNFs. For the case where the purpose of heat transfer is to cool an equipment such as electrical device, guaranteeing heat transfer efficiency (Nu) is more important than decreasing useful energy loss ( ST ); thus, we propose a large ? relative to the flow direction. For industrial processes, where energy loss ( ST ) have to be particularly considered, a small ? is recommended.

  17. Heat capacity and thermodynamic properties for coesite and jadeite, reexamination of the quartz-coesite equilibrium boundary

    USGS Publications Warehouse

    Hemingway, B.S.; Bohlen, S.R.; Hankins, W.B.; Westrum, E.F., Jr.; Kuskov, O.L.

    1998-01-01

    The heat capacities of synthetic coesite and jadeite were measured between about 15 and 850 K by adiabatic and differential scanning calorimetry. The experimental data were smoothed and estimates were made of heat capacities to 1800 K. The following equations represent our estimate of the heat capacities of coesite and jadeite between 298.15 and 1800 K: [see original article for formula]. Tables of thermodynamic values for coesite and jadeite to 1800 K are presented. The entropies of coesite and jadeite are 40.38 ?? 0.12 and 136.5 ?? 0.32 J/(mol.K), respectively, at 298.15 K. The entropy for coesite derived here confirms the value published earlier by Holm et al. (1967). We have derived an equation to describe the quartz-coesite boundary over the temperature range of 600 to 1500 K, P(GPa) = 1.76 + 0.001T(K). Our results are in agreement with the enthalpy of transition reported by Akaogi and Navrotsky (1984) and yield -907.6 ?? 1.4 kJ/mol for the enthalpy of formation of coesite from the elements at 298.15 K and 1 bar, in agreement with the value recommended by CODATA (Khodakovsky et al. 1995). Several sources of uncertainty remain unacceptably high, including: the heat capacities of coesite at temperatures above about 1000 K; the heat capacities and volumetric properties of ?? quartz at higher pressures and at temperatures above 844 K; the pressure corrections for the piston cylinder apparatus used to determine the quartz-coesite equilibrium boundary.

  18. THERMODYNAMIC PROPERTIES AND

    E-print Network

    Heller, Barbara

    : No process is possible which consists solely in the transfer of heat from one temperature level to a higher in reversible process The only requirements are that the system be closed and that the change occur betweenP ­ SdT Maxwell's equation #12;EXAMPLE 1 Air at 1 bar and 298.15K (25) is compressed to 5 bar and 298

  19. Hydrogen technology survey: Thermophysical properties

    NASA Technical Reports Server (NTRS)

    Mccarty, R. D.

    1975-01-01

    The thermodynamic functions, transport properties, and physical properties of both liquid and gaseous hydrogen are presented. The low temperature regime is emphasized. The tabulation of the properties of normal hydrogen in both Si and engineering units is given along with the tabulation of parahydrogen.

  20. Correlation and prediction of thermodynamic properties of nonelectrolytes at infinite dilution in water over very wide temperature and pressure ranges (2000 K and 10 GPa)

    NASA Astrophysics Data System (ADS)

    Plyasunov, Andrey V.

    2015-11-01

    Thermodynamic modeling of natural processes involving deep aqueous fluids requires the knowledge of the values of chemical potentials (the Gibbs energy) of aqueous species. An accurate prediction of thermodynamic properties at high T and P is a strong challenge. It is shown that geochemical models, including the well-known HKF-model, cannot be recommended for an indiscriminate use at supercritical temperatures to predict chemical potentials of nonelectrolytes at infinite dilution in water. Nevertheless, sufficiently accurate predictions of ?2? (the fugacity coefficients at infinite dilution in water) of aqueous nonelectrolytes up to 2000 K and water densities up to 1500 kg m-3, i.e. pressure up to 10-12 GPa, can be made relying on known theoretical relations valid at various parts of the phase diagram of water. In essence, the method, proposed in this work, consists in the interpolation of properties between two known limits: the first one, at low water densities, is defined by the values of the second virial coefficients for water-solute interactions, and the second, at high water densities - by predictions of the theory of a mixture of hard spheres. The interpolation at moderate temperatures (700-1300 K) and water densities (500-900 kg m-3) is simplified by sufficiently accurate predictions of properties using a semiempirical variant of a corresponding-states principle. Presented examples of the prediction of fugacity coefficients of "gases" at infinite dilution in water and of an aqueous solubility of corundum over very wide ranges of water densities/pressures demonstrate the potential and generality of the proposed methods of evaluating the thermodynamic properties of aqueous neutral compounds.

  1. Ab initio calculations of mechanical, thermodynamic and electronic structure properties of mullite, iota-alumina and boron carbide

    NASA Astrophysics Data System (ADS)

    Aryal, Sita Ram

    The alumino-silicate solid solution series (Al 4+2xSi2-2 xO10-x) is an important class of ceramics. Except for the end member (x=0), Al2 SiO5 the crystal structures of the other phases, called mullite, have partially occupied sites. Stoichiometric supercell models for the four mullite phases 3Al2O 3 · 2SiO2 · 2Al 2O3 · SiO2, 4 Al2O3· SiO 2, 9Al2O3 · SiO2, and iota-Al2 O3 (iota-alumina) are constructed starting from experimentally reported crystal structures. A large number of models were built for each phase and relaxed using the Vienna ab initio simulation package (VASP) program. The model with the lowest total energy for a given x was chosen as the representative structure for that phase. Electronic structure and mechanical properties of mullite phases were studied via first-principles calculations. Of the various phases of transition alumina, iota-Al 2O3 is the least well known. In addition structural details have not, until now, been available. It is the end member of the aluminosilicate solid solution series with x=1. Based on a high alumina content mullite phase, a structural model for iota- Al2O3 is constructed. The simulated x-ray diffraction (XRD) pattern of this model agrees well with a measured XRD pattern. The iota-Al2 O3 is a highly disordered ultra-low-density phase of alumina with a theoretical density of 2854kg/m3. Using this theoretically constructed model, elastic, thermodynamic, electronic, and spectroscopic properties of iota-Al2 O3 have been calculated and compared it with those of alpha- Al2O3 and gamma- Al2O3. Boron carbide (B4C) undergoes an amorphization under high velocity impacts. The mechanism of amorphization is not clear. Ab initio methods are used to carry out large-scale uniaxial compression simulations on two polytypes of stoichiometric boron carbide (B4C), B 11C-CBC, and B12- CCC where B11C or B12 is the 12-atom icosahedron and CBC or CCC is the three-atom chain. The simulations were performed on large supercells of 180 atoms. Simulated results indicate bending of the three-atom chain leads to the amorphization of the B 11C-CBC (B12-CCC ) at a uniaxial strain s=0.23 (0.22) and with a maximum stress of 168 (151) GPa. The mechanism of amorphization is analyzed with radial pair distribution function (RPDF), total density of states (TDOS), and the distribution of effective charges on atoms.

  2. Pressure and doping dependent elastic and thermodynamical properties of Ga{sub 1-x}In{sub x}P mixed valent compounds

    SciTech Connect

    Varshney, Dinesh; School of Instrumentation, USIC Bhawan, Devi Ahilya University, Khandwa Road Campus, Indore 452001 ; Dagaonkar, Geetanjali; Varshney, Meenu

    2010-08-15

    Using a phenomenological lattice model incorporating the long-range Coulomb and charge transfer caused by the deformation of the electron shells of the overlapping ions and the Hafemeister and Flygare type short-range overlap repulsion extended upto the second neighbor ions and the van der Waals (vdW) interaction, we present a comprehensive study to understand the effects of pressure on the elastic behavior as ductility (brittleness) and thermodynamical properties of Ga{sub 1-x}In{sub x}P. Estimated phase-transition pressure and the vast volume discontinuity in pressure-volume phase diagram confirm the structural phase transition from zinc blende (B3) to rock salt (B1) phase. From the elastic constants the Poisson's ratio {nu}, the ratio R{sub S/B} of S (Voigt averaged shear modulus) over B (bulk modulus), elastic wave velocity, average wave velocity and thermodynamical property Debye temperature is calculated. The Poisson's ratio {nu} and the ratio R{sub S/B} allows one to conclude that Ga{sub 1-x}In{sub x}P is brittle in zinc blende (B3) and ductile nature is inferred in sodium chloride (B1) phase. To our knowledge this is the first quantitative theoretical prediction of the doping and pressure dependent elastic properties for mixed valent Ga{sub 1-x}In{sub x}P compounds and still awaits experimental confirmations.

  3. Electronic, elastic, vibrational, and thermodynamic properties of type-VIII clathrates Ba8Ga16Sn30 and Ba8Al16Sn30 by first principles

    NASA Astrophysics Data System (ADS)

    Norouzzadeh, Payam; Myles, Charles W.; Vashaee, Daryoosh

    2013-10-01

    We present the results of studying electronic, elastic, vibrational, and thermodynamic properties of type-VIII clathrates Ba8Ga16Sn30 Ba8Al16Sn30 calculated from a first-principles approach. The calculations utilize the generalized gradient approximation to density functional theory. The results indicate that the Ba8Ga16Sn30 and Ba8Al16Sn30 are indirect semiconductors with fundamental band gaps of 160 meV and 315 meV, respectively. It was also found that the stiffness of Al containing type-VIII clathrate does not show any significant change against the uniform pressure, shearing, and linear strains. The phonon spectrum and the phonon state densities of these compounds as well as the Raman and infrared active modes were further calculated and the effects of replacing the Ga with Al atoms on the properties of interest were discussed. The calculated elastic, vibrational, and thermodynamic properties along with Raman and IR spectra are reported for the first time. The identification of the Raman and infrared active modes will be especially useful for the experimental characterizations of these compounds. Our calculations show that the heat capacities of these clathrates increase smoothly with temperature and approach the Dulong-Petit value at about room temperature, which agrees with the existing experimental data.

  4. Thermophysical properties of argon

    SciTech Connect

    Jaques, A.

    1988-02-01

    The entire report consists of tables of thermodynamic properties (including sound velocity, thermal conductivity and diffusivity, Prandtl number, density) of argon at 86 to 400/degree/K, in the form of isobars over 0.9 to 100 bars. (DLC)

  5. The Fundamental Property Relation.

    ERIC Educational Resources Information Center

    Martin, Joseph J.

    1983-01-01

    Discusses a basic equation in thermodynamics (the fundamental property relation), focusing on a logical approach to the development of the relation where effects other than thermal, compression, and exchange of matter with the surroundings are considered. Also demonstrates erroneous treatments of the relation in three well-known textbooks. (JN)

  6. Structural, Electronic, Optical and Thermodynamic Properties of PbS, PbSe and Their Ternary Alloy PbS1-xSex

    NASA Astrophysics Data System (ADS)

    Labidi, M.; Meradji, H.; Ghemid, S.; Labidi, S.; El Haj Hassan, F.

    On the basis of ab initio calculations employing density functional theory (DFT), we investigate the structural, electronic, optical and thermodynamic properties of two binaries: PbS and PbSe in rock-salt structures. In addition, several compositions with various ordered structures of PbS1-xSex alloys were studied. The calculations were performed using the full potential linearized augmented plane wave (FP-LAPW) method within the generalized gradient approximation (GGA). Various quantities, such as equilibrium lattice constants, bulk modulus, band structures and refractive index for all Se-concentrations are presented. The microscopic origins of the gap bowing were explained by using the approach of Zunger and coworkers. On the other hand, the thermodynamic stability of these alloys was investigated by calculating the excess enthalpy of mixing ?Hm as well as the phase diagram.

  7. Thermodynamic and rheological properties of solid-liquid systems in coal processing. Quarterly technical report, December 1, 1992--February 28, 1993

    SciTech Connect

    Kabadi, V.N.; Ilias, S.

    1993-12-31

    Very little data is available on the thermodynamic properties of coal model compounds in liquid phase at high pressures. The authors present preliminary compilations of available data. It is anticipated that they will require vapor pressure and saturated liquid density data for coal model compounds in their high pressure liquid equation of state development. These data sets have also been compiled and are presented. They have at this time completed a review of techniques for high pressure density measurements. Some thought is being given to the possibility of building an apparatus to carry out density measurements for selected model compounds. Finally, they reproduce the Thomson et al equation and describe their preliminary procedure to test this equation with available high pressure thermodynamic data. They acknowledge the possibility that a number of modifications of the Thomson equation will be necessary before a reasonably accurate liquid state equation of state for coal model compound emerges.

  8. School Property.

    ERIC Educational Resources Information Center

    Delon, Floyd G.

    This chapter, one of seven in the 1973 Yearbook of School Law, reviews the status and development of the law governing school property during 1972. It is based primarily on an analysis of court decisions during that year. The cases divide into (1) those dealing with the acquisition, management, and disposition of school property; and (2) those…

  9. Computer program for obtaining thermodynamic and transport properties of air and products of combustion of ASTM-A-1 fuel and air

    NASA Technical Reports Server (NTRS)

    Hippensteele, S. A.; Colladay, R. S.

    1978-01-01

    A computer program for determining desired thermodynamic and transport property values by means of a three-dimensional (pressure, fuel-air ratio, and either enthalpy or temperature) interpolation routine was developed. The program calculates temperature (or enthalpy), molecular weight, viscosity, specific heat at constant pressure, thermal conductivity, isentropic exponent (equal to the specific heat ratio at conditions where gases do not react), Prandtl number, and entropy for air and a combustion gas mixture of ASTM-A-1 fuel and air over fuel-air ratios from zero to stoichiometric, pressures from 1 to 40 atm, and temperatures from 250 to 2800 K.

  10. A computationally efficient and accurate numerical representation of thermodynamic properties of steam and water for computations of non-equilibrium condensing steam flow in steam turbines

    NASA Astrophysics Data System (ADS)

    Hrubý, Jan

    2012-04-01

    Mathematical modeling of the non-equilibrium condensing transonic steam flow in the complex 3D geometry of a steam turbine is a demanding problem both concerning the physical concepts and the required computational power. Available accurate formulations of steam properties IAPWS-95 and IAPWS-IF97 require much computation time. For this reason, the modelers often accept the unrealistic ideal-gas behavior. Here we present a computation scheme based on a piecewise, thermodynamically consistent representation of the IAPWS-95 formulation. Density and internal energy are chosen as independent variables to avoid variable transformations and iterations. On the contrary to the previous Tabular Taylor Series Expansion Method, the pressure and temperature are continuous functions of the independent variables, which is a desirable property for the solution of the differential equations of the mass, energy, and momentum conservation for both phases.

  11. Investigation of the pressure dependent thermodynamic and elastic properties of 1,3,5-triamino-2,4,6-trinitrobenzene using dispersion corrected density functional theory

    SciTech Connect

    Rykounov, A. A.

    2015-06-07

    The influence of pressure on the thermodynamic, structural, and elastic properties of the 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) molecular crystal at T?=?0 is systematically studied. Calculations are carried out using density functional theory methods in a plane wave basis set with dispersion corrections for the exchange-correlation part of total energy, and ultrasoft pseudopotentials. The equilibrium unit cell parameters, the cold compression curve in the pressure range of 0–50?GPa and the sound speeds are computed. The effect of finite pressure on the molecular structure of TATB is elucidated from the analysis of relative changes in the intra- and intermolecular geometrical parameters. For the first time, the full set of elastic constants of this crystal at zero and non-zero pressures is determined from ab initio calculations. The resulted structural, elastic, and acoustic properties of TATB are shown to be in a good agreement with available experimental and theoretical data.

  12. First-principles investigation of the elastic, electronic, and thermodynamic properties of a nitrogen-doped (Ti0.75W0.25)C solid solution

    NASA Astrophysics Data System (ADS)

    Gao, Zhe; Kang, Shinhoo

    2013-03-01

    (Ti00.75W0.25)C and (Ti0.75W0.25)(C0.75N0.25) are the major components of hard materials used, for example, in cutting tools. The material properties of these components were investigated using first principle methods. The elastic constants and moduli indicated that (Ti0.75W0.25)C was expected to yield good mechanical properties, with the exception of a poor shear modulus, at working temperatures, around 800 °C (1073 K), relevant to cutting tool operation. The shear modulus worsened upon substitution of nitrogen for carbon due to unfavorable shifts in the material electronic and vibrational structures. From a thermodynamic perspective, (Ti0.75W0.25)(CN0.25) was more stable due to a lower free energy of formation at T<2000 K.

  13. Thermodynamic, structural and electronic, properties of SnO2: By GGA and GGA + trans-blaha-modified Becke-Johnson (TB-mBJ) calculation

    NASA Astrophysics Data System (ADS)

    Bezzerrouk, M. A.; Hassan, M.; Baghdad, R.; Reguieg, S.; Bousmaha, M.; Kharroubi, B.; Bouhafs, B.

    2015-08-01

    In this paper we have investigated the structural, electronic and thermodynamic properties of tin oxide (SnO2) using the full-potential linearized augmented plane wave method (FP-LAPW) within the framework of density functional theory (DFT) as implemented in the Wien2k package within the generalized gradient approximation (GGA) and GGA plus trans-blaha-modified Becke-Johnson (TB-mBJ) as the exchange correlation. From the electronic properties, SnO2 has a direct band gap in (?-?) direction with a value of 2.86 eV. The quasi-harmonic Debye model, using a set of total energy versus volume calculations is applied to study the thermal and vibrational effects. Temperature and pressure effects on the structural parameters, such as thermal expansion, heat capacities and Debye temperature are investigated from the non-equilibrium Gibbs function.

  14. INTELLECTUAL PROPERTY LAW Intellectual Property

    E-print Network

    Loudon, Catherine

    faculty at UCI Law have written treatises, monographs, casebooks and articles that are regularlyINTELLECTUAL PROPERTY LAW #12;Intellectual Property Scholarship at UCI Law Consistently recognized to UC Irvine's No. 6 ranking among U.S. law school faculties for scholarly impact in 20151 -- the IP

  15. Electrochemical and thermodynamic properties of Ln(III) (Ln = Eu, Sm, Dy, Nd) in 1-butyl-3-methylimidazolium bromide ionic liquid.

    PubMed

    Yang, Xiao; He, Ling; Qin, Song; Tao, Guo-Hong; Huang, Ming; Lv, Yi

    2014-01-01

    The electrochemical behavior and thermodynamic properties of Ln(III) (Ln = Eu, Sm, Dy, Nd) were studied in 1-butyl-3-methylimidazolium bromide ionic liquid (BmimBr) at a glassy carbon (GC) electrode in the range of 293-338 K. The electrode reaction of Eu(III) was found to be quasi-reversible by the cyclic voltammetry, the reactions of the other three lanthanide ions were regarded as irreversible systems. An increase of the current intensity was obtained with the temperature increase. At 293 K, the cathodic peak potentials of -0.893 V (Eu(III)), -0.596 V (Sm(III)), -0.637 V (Dy(III)) and -0.641 V (Nd(III)) were found, respectively, to be assigned to the reduction of Ln(III) to Ln(II). The diffusion coefficients (Do), the transfer coefficients (?) of Ln(III) (Ln = Eu, Sm, Dy, Nd) and the charge transfer rate constants (ks) of Eu(III) were estimated. The apparent standard potential (E0*) and the thermodynamic properties of the reduction of Eu(III) to Eu(II) were also investigated. PMID:24752584

  16. Ab Initio Thermodynamic Study of the CO2 Capture Properties of Potassium Carbonate Sesquihydrate, K2CO3·1.5H2O

    SciTech Connect

    Duan, Yuhua; Luebkes,David R.; Pennline, Henry W; Li, Bingyun Li; Janik, Michael J.; Halley, Woods

    2012-01-01

    By combining density functional theory and lattice phonon dynamics, the thermodynamic properties of CO2 absorption/desorption reactions with dehydrated potassium carbonates through K2CO3·1.5H2O + CO2 = 2KHCO3 + 0.5H2O(g) are analyzed. The energy change and the chemical potential of this reaction have been calculated and used to evaluate its thermodynamic properties and phase transitions. The results indicate that the K2CO3·1.5H2O can only be applied for postcombustion CO2 capture technology at temperatures lower than its phase transition temperature, which depends on the CO2 pressure and the steam pressure with the best range being PH2O ? 1.0 bar. Above the phase transition temperature, the sorbent will be regenerated into anhydrous K2CO3. If the steam pressure PH2O is much greater than 1.0 bar, it is possible to use the K2CO3·1.5H2O sorbent for precombustion CO2 capture technology. Compared to anhydrous K2CO3, K2CO3·1.5H2O requires less energy for regeneration.

  17. Molecular simulation of fluids with non-identical intermolecular potentials: Thermodynamic properties of 10-5 + 12-6 Mie potential binary mixtures

    SciTech Connect

    Stiegler, Thomas; Sadus, Richard J.

    2015-02-28

    General methods for combining interactions between particles characterised by non-identical intermolecular potentials are investigated. The combination methods are tested by performing molecular dynamics simulations to determine the pressure, energy, isochoric and isobaric heat capacities, thermal expansion coefficient, isothermal compressibility, Joule-Thomson coefficient, and speed of sound of 10-5 + 12-6 Mie potential binary mixtures. In addition to the two non-identical Mie potentials, mixtures are also studied with non-identical intermolecular parameters. The combination methods are compared with results obtained by simply averaging the Mie exponents. When either the energy or size parameters are non-identical, very significant differences emerge in the thermodynamic properties predicted by the alternative combination methods. The isobaric heat capacity is the thermodynamic property that is most affected by the relative magnitude of the intermolecular potential parameters and the method for combining non-identical potentials. Either the arithmetic or geometric combination of potentials provides a simple and effective way of performing simulations involving mixtures of components characterised by non-identical intermolecular potentials, which is independent of their functional form.

  18. Structural and electronic properties of Li8ZrO6 and its CO2 capture capabilities: an ab initio thermodynamic approach

    SciTech Connect

    Duan, Y

    2013-05-24

    The structural, electronic, and phonon properties of Li8ZrO6 are investigated with the application of density functional theory and lattice phonon dynamics. Based on the calculated data, the thermodynamics of CO2 absorption?desorption for Li8ZrO6 is analyzed and compared with those of Li2ZrO3 and Li6Zr2O7. The band gap of Li8ZrO6 is indirect along G?L with a value of 4.74 eV. From the calculated thermodynamic properties of Li8ZrO6 reacting with CO2, we found that Li8ZrO6 could be regenerated at high temperatures (>1100 K). Our results indicated that the lithium zirconate with a lower Li2O/ZrO2 ratio has a lower turnover temperature. Hence, by mixing or doping two or more materials to form a new material, it is possible to find or synthesize CO2 sorbents that can fit the industrial needs for optimal performance. Although the CO2 capture capacity of Li8ZrO6 is much higher than that of Li2ZrO3, the high energy required for regeneration, the capacity loss during long absorption?desorption cycles, solid sintering at high temperature, and the material cost may affect its overall capture performance. Our results also provided some general guidelines for designing new CO2 sorbents.

  19. First-principles calculations of structural, elastic, thermodynamic, and electronic properties of anti-perovskites A III CNi3 (A III = Al, Ga, In)

    NASA Astrophysics Data System (ADS)

    Saadaoui, Fatiha; Driss Khodja, Fatima Zohra; Kadoun, Abd-Ed-Daïm; Driss Khodja, Mohammed; Elias, Abdelkader; Boudali, Abdelkader

    2015-12-01

    We have performed first-principles calculations of structural, elastic, thermodynamic, and electronic properties of anti-perovskites AIIICNi3 (AIII = Al, Ga, In), by using the full-potential linearized augmented plane wave (FP-LAPW) method combined with the quasi-harmonic Debye model. We carried out our calculations within the local density approximation (LDA) and the generalized gradient approximation (GGA-PBE and GGA-PBEsol functionals). Our results constitute interesting first predictions in the case of many elastic parameters of the anti-perovskites AIIICNi3, among them elastic parameters of AlCNi3 and GaCNi3 and some polycrystalline elastic parameters of InCNi3. We also report for the first time calculated values, at ambient conditions, of Grüneisen parameter, thermal expansion coefficient, specific heat at constant pressure, specific heat at constant volume, isothermal bulk modulus, and adiabatic bulk modulus for AlCNi3, GaCNi3, and InCNi3. Band structure, total and partial densities of states, and charge density have been obtained and analyzed. Electronic structure results show metallic behavior for the three compounds. Ni 3 d states play dominant role near the Fermi level and there is a strong hybridization between Ni 3 d and C 2 p states. In addition, as AIIICNi3 synthesized samples are expected to be carbon-deficient, we calculated structural, elastic, and thermodynamic properties of sub-stoichiometric AlC x Ni3 materials.

  20. Thermodynamic properties of aqueous sodium sulfate solutions to 773 K and 3 GPa derived from acoustic velocity measurements in the diamond anvil cell.

    PubMed

    Mantegazzi, Davide; Sanchez-Valle, Carmen; Reusser, Eric; Driesner, Thomas

    2012-12-14

    The thermodynamic properties of a 1 m Na(2)SO(4) solution have been determined to 773 K and 3 GPa from acoustic velocity measurements in externally heated diamond anvil cell using Brillouin spectroscopy. The measured acoustic velocities were inverted to obtain the density of the aqueous electrolyte solution with an accuracy of 0.3%-0.5%, and an equation of state (EoS) valid in the 293-773 K and 0.4-3 GPa range is proposed. The new EoS reproduces the experimental acoustic velocity data with a maximal deviation of 1.5% and allows deriving all thermodynamic properties of the aqueous solution, including isobaric heat capacity (C(P)), thermal expansion (?(P)), and compressibility (?) with an accuracy better than 3%-8%. The addition of dissolved sulfate species decreases the compressibility of water, consistent with the structure-maker character of SO(4)(2-) ions in solution that enhance the hydrogen-bond network of the solvent. PMID:23249011

  1. Electrochemical and Thermodynamic Properties of Ln(III) (Ln?=?Eu, Sm, Dy, Nd) in 1-Butyl-3-Methylimidazolium Bromide Ionic Liquid

    PubMed Central

    Yang, Xiao; He, Ling; Qin, Song; Tao, Guo-Hong; Huang, Ming; Lv, Yi

    2014-01-01

    The electrochemical behavior and thermodynamic properties of Ln(III) (Ln?=?Eu, Sm, Dy, Nd) were studied in 1-butyl-3-methylimidazolium bromide ionic liquid (BmimBr) at a glassy carbon (GC) electrode in the range of 293–338 K. The electrode reaction of Eu(III) was found to be quasi-reversible by the cyclic voltammetry, the reactions of the other three lanthanide ions were regarded as irreversible systems. An increase of the current intensity was obtained with the temperature increase. At 293 K, the cathodic peak potentials of ?0.893 V (Eu(III)), ?0.596 V (Sm(III)), ?0.637 V (Dy(III)) and ?0.641 V (Nd(III)) were found, respectively, to be assigned to the reduction of Ln(III) to Ln(II). The diffusion coefficients (Do), the transfer coefficients (?) of Ln(III) (Ln?=?Eu, Sm, Dy, Nd) and the charge transfer rate constants (ks) of Eu(III) were estimated. The apparent standard potential (E0*) and the thermodynamic properties of the reduction of Eu(III) to Eu(II) were also investigated. PMID:24752584

  2. Development of an Experimental Data Base and Theories for Prediction of Thermodynamic Properties of Aqueous Electrolytes and Nonelectrolytes of Geochemical Significance at Supercritical Temperatures and Pressures.

    SciTech Connect

    Wood, Robert H.

    2005-10-11

    The objective of this research was to combine new experimental measurements on heat capacities, volumes, and association constants of key compounds with theoretical equations of state and with first principles quantum mechanical calculations to generate predictions of thermodynamic data. The resulting thermodynamic data allow quantitative models of geochemical processes at high temperatures and pressures. Research funded by a DOE grant to Prof. Robert Wood at the University of Delaware involved the development of new theoretical equations of state for aqueous solutions of electrolytes and non-electrolytes, methods to estimate thermodynamic data not available from experiments, collection of data on model compounds through experiments and predictions of properties using ab initio quantum mechanics. During the last three and a half years, with support from our DOE grant, 16 papers have been accepted or published, and 3 more are in preparation. Results of this research have been reported in numerous invited and contributed presentations at national and international meetings. For this report, we will briefly comment on the highlights of the last 3 and a half years and give a complete list of papers published, accepted, or submitted during these years.

  3. Group additivity equations of state for calculating the standard molal thermodynamic properties of aqueous organic species at elevated temperatures and pressures

    NASA Astrophysics Data System (ADS)

    Amend, Jan P.; Helgeson, Harold C.

    1997-01-01

    Group additivity equations of state for aqueous organic molecules have been generated by combining the revised Helgeson-Kirkham-Flowers (HKF) equations of state ( Shock and Helgeson, 1988, 1990; Tanger and Helgeson, 1988; Shock et al., 1989, 1992) with experimental values of the standard molal properties of aqueous alkanes, alkanols, alkylbenzenes, car?ylic acids, amides, and amines. Equations of state parameters for the groups represented by -CH 2-, -CH 3, -CHCH 3-, -C 6H 5, -CH 2OH, -COOH, -CONH 2, and -CH 2NH 2 were determined by regression of the experimental data. This procedure permits calculation of the standard molal thermodynamic properties of these groups at elevated temperatures and pressures. Although curves representing the apparent standard molal Gibbs free energies (? G°) and enthalpies (? H°) of formation, and the standard molal entropies ( S°) of the groups as a function of temperature and pressure are respectively similar for each of them, the temperature dependence of the standard molal heat capacities ( Cp°) and volumes ( V°) of a number of the groups are quite different from one another. For example, the standard molal heat capacities of the hydrocarbon groups minimize with increasing temperature, but those of -CH 2OH and -CH 2NH 2 maximize. Computed values of ? G°, ? H°, S°, Cp°, V°, and the equations of state parameters for the various groups were used together with group additivity relations to generate corresponding values of these properties for aqueous n-alkanes, 2-methylalkanes, n-alkylbenzenes, n-alkanols, n-car?ylic acids, n-amides, and n-amines at temperatures ? 250°C and pressures ? 1 kbar. The validity and generality of the equations of state are supported by the fact that predicted equilibrium constants for liquid n-alkane solubility reactions in water compare favorably with experimental values reported in the literature for temperatures as high as 200°C. Furthermore, equilibrium constants for aqueous ethane coexisting with ethene at 325 and 350°C at 350 bars predicted from the equations of state are in close agreement with independently determined experimental values reported by Seewald (1994). The standard molal thermodynamic properties and equations of state parameters reported below provide the means to characterize the thermodynamic behavior of a wide variety of aqueous organic species involved in hydrothermal reactions at elevated temperatures and pressures.

  4. Magnetic, electrical, and thermodynamic properties of NpIr: Ambient and high-pressure measurements, and electronic structure calculations

    NASA Astrophysics Data System (ADS)

    Walker, H. C.; McEwen, K. A.; Griveau, J.-C.; Eloirdi, R.; Amador, P.; Maldonado, P.; Oppeneer, P. M.; Colineau, E.

    2015-05-01

    We present bulk property measurements of NpIr, a newly synthesized member of the Np-Ir binary phase diagram, which is isostructural to the noncentrosymmetric pressure-induced ferromagnetic superconductor UIr. Magnetic susceptibility, electronic transport properties at ambient and high pressure, and heat capacity measurements have been performed for temperatures T =0.55 -300 K in a range of magnetic fields up to 14 T and under pressure up to 17.3 GPa. These reveal that NpIr is a moderately heavy fermion Kondo system with strong antiferromagnetic interactions, but there is no evidence of any phase transition down to 0.55 K or at the highest pressure achieved. Experimental results are compared with ab initio calculations of the electronic band structure and lattice heat capacity. An extremely low lattice thermal conductivity is predicted for NpIr at temperatures above 300 K.

  5. Methanol conversion to light olefins over nanostructured CeAPSO-34 catalyst: Thermodynamic analysis of overall reactions and effect of template type on catalytic properties and performance

    SciTech Connect

    Aghamohammadi, Sogand; Haghighi, Mohammad; Charghand, Mojtaba

    2014-02-01

    Graphical abstract: In this research nanostructured CeAPSO-34 was synthesized to explore the effect of TEAOH and morpholine on its physiochemical properties and MTO performance. Prepared catalysts were characterized with XRD, FESEM, BET, FTIR and NH3-TPD techniques. The results indicated that the nature of the template determines the physiochemical properties of CeAPSO-34 due to different rate of crystal growth. The catalyst obtained by using morpholine showed longer life time as well as sustaining light olefins selectivity at higher values. Furthermore, a comprehensive thermodynamic analysis of overall reactions network was carried out to address the major channels of methanol to olefins conversion. - Highlights: • Introduction of Ce into SAPO-34 framework. • Comparison of CeAPSO-34 synthesized using morpholine and TEAOH. • The nature of the template determines the physiochemical properties of CeAPSO-34. • Morpholine enhances catalyst lifetime in MTO process. • Presenting a complete reaction network for MTO process. - Abstract: TEAOH and morpholine were employed in synthesis of nanostructured CeAPSO-34 molecular sieve and used in methanol to olefins conversion. Prepared samples were characterized by XRD, FESEM, EDX, BET, FTIR and NH{sub 3}-TPD techniques. XRD patterns reflected the higher crystallinity of the catalyst synthesized with morpholine. The FESEM results indicated that the nature of the template determines the morphology of nanostructured CeAPSO-34 due to different rate of crystal growth. There was a meaningful difference in the strength of both strong and weak acid sites for CeAPSO-34 catalysts synthesized with TEAOH and morpholine templates. The catalyst synthesized with morpholine showed higher desorption temperature of both weak and strong acid sites evidenced by NH{sub 3}-TPD characterization. The catalyst obtained using morpholine template had the longer lifetime and sustained desired light olefins at higher values. A comprehensive thermodynamic analysis of overall reactions network was carried out to address the major channels of methanol to olefins conversion.

  6. The heat capacities of osumilite from 298.15 to 1000 K, the thermodynamic properties of two natural chlorites to 500 K, and the thermodynamic properties of petalite to 1800 K.

    USGS Publications Warehouse

    Hemingway, B.S.; Robie, R.A.; Kittrick, J.A.; Grew, E.S.; Nelen, J.A.; London, D.

    1984-01-01

    Modifications to an automated low-T, adiabatic calorimeter are described. Thermodynamic data obtained with this instrument are reported for minerals from metamorphic terrains. (U.S. Bureau of Mines Report of Investigations 8451)-J.A.Z.

  7. On the radiative and thermodynamic properties of the cosmic radiations using COBE FIRAS instrument data: III. Galactic far-infrared radiation

    NASA Astrophysics Data System (ADS)

    Fisenko, Anatoliy I.; Lemberg, Vladimir

    2015-07-01

    Using the three-component spectral model describing the FIRAS average continuum spectra, the exact analytical expressions for thermodynamic and radiative functions of Galactic far-infrared radiation are obtained. The COBE FIRAS instrument data in the 0.15–2.88 THz frequency interval at the mean temperatures of T1 = 17.72 K, T2 = 14 K and T3 = 6.73 K are used for calculating the radiative and thermodynamic functions, such as the total radiation power per unit area, total energy density, total emissivity, number density of photons, Helmholtz free energy density, entropy density, heat capacity at constant volume and pressure for the warm, intermediate-temperature and very cold components of the Galactic continuum spectra. The generalized Stefan-Boltzmann law for warm, intermediate-temperature and very cold components is constructed. The temperature dependence of each component is determined by the formula IS–B(T) = ??T6. This result is important when we construct the cosmological models of radiative transfer that can be applied inside the Galaxy. Within the framework of the three-component spectral model, the total number of photons in our Galaxy and the total radiation power (total luminosity) emitted from a surface of the Galaxy are calculated. Their values are NGtotal = 1.3780 × 1068 and IGtotal(T) = 1.0482 × 1036 W. Other radiative and thermodynamic properties of the Galactic far-infrared radiation (photon gas) of the Galaxy are calculated. The expressions for astrophysical parameters, such as the entropy density/Boltzmann constant and number density of the Galactic far-infrared photons are obtained. We assume that the obtained analytical expressions for thermodynamic and radiative functions may be useful for describing the continuum spectra of the far-infrared radiation for other galaxies.

  8. Atmospheric aerosols: Their Optical Properties and Effects

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Measured properties of atmospheric aerosol particles are presented. These include aerosol size frequency distribution and complex retractive index. The optical properties of aerosols are computed based on the presuppositions of thermodynamic equilibrium and of Mie-theory.

  9. FP-LMTO study of structural, electronic, thermodynamic and optical properties of Mg x Cd1- x Se alloys

    NASA Astrophysics Data System (ADS)

    Bensaid, D.; Ameri, M.; El Hanani, M. Din; Azaz, Y.; Bendouma, D.; Al-Douri, Y.; Ameri, I.

    2014-12-01

    Structural, electronic and optical properties of Mg x Cd1- x Se (0 ? x ? 1) are calculated for the first time using density functional theory. Our results show that these properties are strongly dependent on molar fraction of particular components — x. The bond between Cd and Se is partially covalent and the covalent nature of the bond decreases as the concentration of Mg increases from 0 % to 100 %. It is found that Mg x Cd1- x Se has a direct band gap in the entire range of x and the band gap of the alloy increases from 0.43 to 2.46 eV with the increase in Mg concentration. Frequency dependent dielectric constants ?1(?), ?2(?) refractive index n(?) are also calculated and discussed in detail. The peak value of refractive indices shifts to higher energy regions with the increase in Mg. The larger value of the extraordinary refractive index confirms that the material is a positive birefringence crystal. The present comprehensive theoretical study of the optoelectronic properties of the material predicts that it can be effectively used in optoelectronic applications in the wide range of spectra: IR, visible and UV. In addition, we have also predicted the heat capacities (C V ), the entropy (S), the internal energy (U) and the Helmholtz free energy (F) of Mg x Cd1- x Se ternary alloys.

  10. Thermophysical Properties of Hydrocarbon Mixtures

    National Institute of Standards and Technology Data Gateway

    SRD 4 NIST Thermophysical Properties of Hydrocarbon Mixtures (PC database for purchase)   Interactive computer program for predicting thermodynamic and transport properties of pure fluids and fluid mixtures containing up to 20 components. The components are selected from a database of 196 components, mostly hydrocarbons.

  11. Thermophysical properties

    SciTech Connect

    Kayser, R.F.

    1992-10-01

    Numerous fluids have been identified as promising alternative refrigerants, but much of the information needed to predict their behavior as pure fluids and as components in mixtures does not exist. In particular, reliable thermophysical properties data and models are needed to predict the performance of the new refrigerants in heating and cooling equipment, and to design and optimize equipment to be reliable and energy efficient. Objective of this project is to provide highly accurate, selected thermophysical properties data for Refrigerants 32, 123, 124, and 125, and to use these data to fit simple and complex equations of state and detailed transport property models. The new data will fill gaps in the existing data sets and resolve the problems and uncertainties that exist in and between the data sets. This report describes the progress made during the third quarter of this fifteen-month project, which was initiated in late January, 1992.

  12. Conformational stability, vibrational spectra, NLO properties, NBO and thermodynamic analysis of 2-amino-5-bromo-6-methyl-4-pyrimidinol for dye sensitized solar cells by DFT methods.

    PubMed

    Anitha, E Gladis; Vedhagiri, S Joseph; Parimala, K

    2015-04-01

    The Fourier transform infrared (FT-IR) and Fourier transform Raman (FT-Raman) spectra of 2-amino-5-bromo-6-methyl-4-pyrimidinol (ABrMP) were recorded in the region 4000-400 and 3500-100 cm(-1), respectively. The conformational stability, geometrical structure, vibrational frequencies, infrared intensities and Raman activities were carried out by DFT (B3LYP and LSDA) methods with 6-311++G(d,p) basis set. The calculated results show good agreement with observed spectra. The charge delocalization have been analyzed using NBO analysis by LSDA/6-311++G(d,p) level of theory. The NLO properties (?, ?0, ??, ?0 and ?vec) have been computed quantum mechanically. The calculated HOMO and LUMO energies show that, the charge transfer occurs within the molecule. The solvent effects have been calculated using TD-DFT and the results are in good agreement with experimental measurements. The other molecular properties like Mulliken population analysis, electrostatic potential (ESP) and thermodynamic properties of the title compound at the different temperatures have been calculated. PMID:25645233

  13. Insight into structural, mechanical, electronic and thermodynamic properties of intermetallic phases in Zr-Sn system from first-principles calculations

    NASA Astrophysics Data System (ADS)

    Liu, Shuai; Zhan, Yongzhong; Wu, Junyan; Wei, Xuanchen

    2015-11-01

    The structural, phase stabilities, mechanical, electronic and thermodynamic properties of intermetallic phases in Zr-Sn system are investigated by using first-principles method. The equilibrium lattice constants, enthalpy of formation (?Hform) and elastic constants are obtained and compared with available experimental and theoretical data. The configuration of Zr4Sn is measured with reasonable precision. The ?Hform of five hypothetical structures are obtained in order to find possible metastable phase for Zr-Sn system. The mechanical properties, including bulk modulus, shear modulus, Young's modulus and Poisson's ratio, are calculated by Voigt-Reuss-Hill approximation and the Zr5Sn4 and Zr5Sn3 show excellent mechanical properties. The electronic density of states for Zr5Sn4, Zr5Sn3 and cP8-Zr3Sn are calculated to further investigate the stability of intermetallic compounds. Through the quasi-harmonic Debye model, the Debye temperature, heat capacity and thermal expansion coefficient under temperature of 0-300 K and pressure of 0-50 GPa for Zr5Sn3 and Zr5Sn4 are deeply investigated.

  14. Conformational stability, vibrational spectra, NLO properties, NBO and thermodynamic analysis of 2-amino-5-bromo-6-methyl-4-pyrimidinol for dye sensitized solar cells by DFT methods

    NASA Astrophysics Data System (ADS)

    Gladis Anitha, E.; Joseph Vedhagiri, S.; Parimala, K.

    2015-04-01

    The Fourier transform infrared (FT-IR) and Fourier transform Raman (FT-Raman) spectra of 2-amino-5-bromo-6-methyl-4-pyrimidinol (ABrMP) were recorded in the region 4000-400 and 3500-100 cm-1, respectively. The conformational stability, geometrical structure, vibrational frequencies, infrared intensities and Raman activities were carried out by DFT (B3LYP and LSDA) methods with 6-311++G(d,p) basis set. The calculated results show good agreement with observed spectra. The charge delocalization have been analyzed using NBO analysis by LSDA/6-311++G(d,p) level of theory. The NLO properties (?, ?0, ??, ?0 and ?vec) have been computed quantum mechanically. The calculated HOMO and LUMO energies show that, the charge transfer occurs within the molecule. The solvent effects have been calculated using TD-DFT and the results are in good agreement with experimental measurements. The other molecular properties like Mulliken population analysis, electrostatic potential (ESP) and thermodynamic properties of the title compound at the different temperatures have been calculated.

  15. Thermodynamic properties of asymptotically anti-de Sitter black holes in d=4 Einstein-Yang-Mills theory

    E-print Network

    Olga Kichakova; Jutta Kunz; Eugen Radu; Yasha Shnir

    2015-03-11

    We investigate the thermodynamics of spherically symmetric black hole solutions in a four-dimensional Einstein--Yang-Mills-SU(2) theory with a negative cosmological constant. Special attention is paid to configurations with a unit magnetic charge. We find that a set of Reissner-Nordstr\\"om--Anti-de Sitter black holes can become unstable to forming non-Abelian hair. However, the hairy black holes are never thermodynamically favoured over the full set of abelian monopole solutions. The thermodynamics of the generic configurations possessing a noninteger magnetic charge is also discussed.

  16. Thermodynamic properties of asymptotically anti-de Sitter black holes in d = 4 Einstein-Yang-Mills theory

    NASA Astrophysics Data System (ADS)

    Kichakova, Olga; Kunz, Jutta; Radu, Eugen; Shnir, Yasha

    2015-07-01

    We investigate the thermodynamics of spherically symmetric black hole solutions in a four-dimensional Einstein-Yang-Mills-SU(2) theory with a negative cosmological constant. Special attention is paid to configurations with a unit magnetic charge. We find that a set of Reissner-Nordström-Anti-de Sitter black holes can become unstable to forming non-Abelian hair. However, the hairy black holes are never thermodynamically favoured over the full set of abelian monopole solutions. The thermodynamics of the generic configurations possessing a noninteger magnetic charge is also discussed.

  17. New modeling and control solutions for integrated microgrid system with respect to thermodynamics properties of generation and demand

    E-print Network

    Liu, Fang-Yu, S.M. Massachusetts Institute of Technology

    2014-01-01

    This thesis investigates microgrid control stability with respect to thermodynamics behaviors of generation and demand. First, a new integrated microgrid model is introduced. This model consists of a combined cycle power ...

  18. Physico-chemical and excess thermodynamic properties of methanol & ethanol with 1, 4-dioxane at 308 K

    NASA Astrophysics Data System (ADS)

    Bedare, G. R.; Bhandakkar, V. D.; Suryavanshi, B. M.

    2012-12-01

    The molecular interaction studies in the binary liquid mixtures of two aliphatic alcohols with 1, 4-dioxane has been carried out at 308 K using ultrasonic technique. Using measured values of ultrasonic velocity, density and viscosity, acoustical parameters such as adiabatic compressibility, free volume, free length and their excess values like VfE, ßaE, LfE are evaluated. From the properties of these excess parameters, the nature and the strength of interactions in these binary systems are discussed. It has been observed that, weak dispersive type intermolecular interactions are confirmed in the systems investigated. Dipole inducement is found to be more predominant in methanol system.

  19. Calculation of the standard partial molal thermodynamic properties of KCl{sup 0} and activity coefficients of aqueous KCl at temperatures and pressures to 1000{degree}C and 5 kbar

    SciTech Connect

    Pokrovskii, V.A.; Helgeson, H.C.

    1997-06-01

    Regression of experimental activity coefficient and dissociation constant data reported in the literature with the Hueckel and Setchenow equations and the revised HKF equations of state generated parameters and thermodynamic properties of dissociated KCl and KCl{sup 0} at 25{degrees}C and bar that can be used to calculate the standard partial molal thermodynamic properties of KCl{sup 0} and the activity coefficients of KCl at temperatures and pressures to 1000{degrees}C and 5 kbar. 46 refs., 6 figs., 4 tabs.

  20. The Alzheimer Disease Protective Mutation A2T Modulates Kinetic and Thermodynamic Properties of Amyloid-? (A?) Aggregation*

    PubMed Central

    Benilova, Iryna; Gallardo, Rodrigo; Ungureanu, Andreea-Alexandra; Castillo Cano, Virginia; Snellinx, An; Ramakers, Meine; Bartic, Carmen; Rousseau, Frederic; Schymkowitz, Joost; De Strooper, Bart

    2014-01-01

    Missense mutations in alanine 673 of the amyloid precursor protein (APP), which corresponds to the second alanine of the amyloid ? (A?) sequence, have dramatic impact on the risk for Alzheimer disease; A2V is causative, and A2T is protective. Assuming a crucial role of amyloid-A? in neurodegeneration, we hypothesized that both A2V and A2T mutations cause distinct changes in A? properties that may at least partially explain these completely different phenotypes. Using human APP-overexpressing primary neurons, we observed significantly decreased A? production in the A2T mutant along with an enhanced A? generation in the A2V mutant confirming earlier data from non-neuronal cell lines. More importantly, thioflavin T fluorescence assays revealed that the mutations, while having little effect on A?42 peptide aggregation, dramatically change the properties of the A?40 pool with A2V accelerating and A2T delaying aggregation of the A? peptides. In line with the kinetic data, A? A2T demonstrated an increase in the solubility at equilibrium, an effect that was also observed in all mixtures of the A2T mutant with the wild type A?40. We propose that in addition to the reduced ?-secretase cleavage of APP, the impaired propensity to aggregate may be part of the protective effect conferred by A2T substitution. The interpretation of the protective effect of this mutation is thus much more complicated than proposed previously. PMID:25253695

  1. Thermodynamic properties of Sr-doped LaMnO{sub 3} perovskite in the La-Sr-Mn-O system

    SciTech Connect

    Zheng, F.; Pederson, L.R.

    1999-08-01

    Thermodynamic properties of Sr-doped perovskite-type lanthanum manganites (LSM) were generated by measuring the electromotive force (EMF) of test materials, using the solid galvanic cell technique. The cell consisted of an anode (SrO/SrF{sub 2}), an electrolyte (CaF{sub 2} or SrF{sub 2}) and a cathode (LSM/SrF{sub 2}). Two types of cells were tested in which type 1 used a CaF{sub 2} electrolyte and type 2 used a SrF{sub 2} electrolyte. The activity of SrO substituting into various LSM compositions was calculated using the measured EMF. The Sr content was varied from 0.16 to 0.6 mol, and the temperature of interest varied from 700 to 1000 C. It was found that the SrO activity decreased with increasing temperature (at fixed composition) and increased with increasing Sr content (at fixed temperature).

  2. Elastic and thermodynamical properties of A15 Nb3X (X = Al, Ga, In, Sn and Sb) compounds — First principles DFT study

    NASA Astrophysics Data System (ADS)

    Sundareswari, M.; Ramasubramanian, Swaminathan; Rajagopalan, Mathrubutham

    2010-11-01

    Elastic and thermodynamical properties of Nb 3X (X = Al, Ga, In, Sn and Sb) compounds are obtained by performing the band structure calculations, using the FP-LAPW method. The calculated lattice constants, elastic constants, Bulk modulus, shear modulus, Young's modulus, Poisson's ratio, Debye temperature and anisotropy ratio are reported and the results agree with the available data. From the present study, it is observed that stiffness and shear resistance are found to be greater in Nb 3Sb than in other compounds. It is more brittle in nature and comparatively harder than other materials under study. The degree of anisotropy decreases as one moves across Nb 3Ga, Nb 3Al, Nb 3In, Nb 3Sb and Nb 3Sn. From the calculated values of the Debye temperature, it is observed that thermal conductivity is greater for Nb 3Sb and less for Nb 3In.

  3. Improved curve fits for the thermodynamic properties of equilibrium air suitable for numerical computation using time-dependent or shock-capturing methods, part 1

    NASA Technical Reports Server (NTRS)

    Tannehill, J. C.; Mugge, P. H.

    1974-01-01

    Simplified curve fits for the thermodynamic properties of equilibrium air were devised for use in either the time-dependent or shock-capturing computational methods. For the time-dependent method, curve fits were developed for p = p(e, rho), a = a(e, rho), and T = T(e, rho). For the shock-capturing method, curve fits were developed for h = h(p, rho) and T = T(p, rho). The ranges of validity for these curves fits were for temperatures up to 25,000 K and densities from 10 to the minus 7th power to 10 to the 3d power amagats. These approximate curve fits are considered particularly useful when employed on advanced computers such as the Burroughs ILLIAC 4 or the CDC STAR.

  4. Theoretical study of the thermodynamic properties, phase transition wave, and phase transition velocity for octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine

    NASA Astrophysics Data System (ADS)

    Long, Yao; Chen, Jun

    2015-09-01

    We develop a phonon-electron free energy model to study the thermodynamic properties and phase transitions of ?-octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine. The bulk modulus, thermal expansion coefficient, specific heat, Hugoniot curve, and phase transition curve are calculated in wide temperature and pressure ranges. The results are in agreement with the available experiments at zero pressure, and are reasonable predictions at high pressure for the lack of experiment. Two kinds of phase transition waves are investigated. We find the velocity of shock-induced phase transition wave is between 3400 m/s and 4700 m/s, and the velocity of self-sustaining phase transition wave is between 1300 m/s and 1900 m/s.

  5. Transport and thermodynamic properties of quasi-two-dimensional purple bronzes A0.9Mo6O17 (A=Na, K)

    NASA Astrophysics Data System (ADS)

    Xu, Xiaofeng; Bangura, A. F.; Niu, C. Q.; Greenblatt, M.; Yue, Song; Panagopoulos, C.; Hussey, N. E.

    2012-05-01

    We report a comparative study of the specific heat, electrical resistivity, and thermal conductivity of the quasi-two-dimensional purple bronzes Na0.9Mo6O17 and K0.9Mo6O17, with special emphasis on the behavior near their respective charge-density-wave transition temperatures TP. The contrasting behavior of both the transport and the thermodynamic properties near TP is argued to arise predominantly from the different levels of intrinsic disorder in the two systems. A significant proportion of the enhancement of the thermal conductivity above TP in Na0.9Mo6O17, and to a lesser extent in K0.9Mo6O17, is attributed to the emergence of phason excitations.

  6. Towards a better understanding on agglomeration mechanisms and thermodynamic properties of TiO2 nanoparticles interacting with natural organic matter

    E-print Network

    Loosli, Frédéric; Berret, Jean-François; Stoll, Serge

    2015-01-01

    Interaction between engineered nanoparticles and natural organic matter is investigated by measuring the exchanged heat during binding process with isothermal titration calorimetry. TiO2 anatase nanoparticles and alginate are used as engineered nanoparticles and natural organic matter to get an insight into the thermodynamic association properties and mechanisms of adsorption and agglomeration. Changes of enthalpy, entropy and total free energy, reaction stoichiometry and affinity binding constant are determined or calculated at a pH value where the TiO2 nanoparticles surface charge is positive and the alginate exhibits a negative structural charge. Our results indicate that strong TiO2-alginate interactions are essentially entropy driven and enthalpically favorable with exothermic binding reactions. The reaction stoichiometry and entropy gain are also found dependent on the mixing order. Finally correlation is established between the binding enthalpy, the reaction stoichiometry and the zeta potential values ...

  7. The thermodynamic properties of 5-vinyltetrazole and poly-5-vinyltetrazole over the temperature range from T ? 0 to 350 K

    NASA Astrophysics Data System (ADS)

    Smirnova, N. N.; Kulagina, T. G.; Bykova, T. A.; Kizhnyaev, V. N.; Petrova, T. L.

    2009-01-01

    The temperature dependences of the heat capacities of 5-vinyltetrazole and poly-5-vinyltetrazole were measured by adiabatic vacuum calorimetry over the temperature range 6-(350-370) K with errors of ˜0.2%. The results were used to calculate the thermodynamic functions of the compounds, C {/p ?}, H ?( T) - H ?(0), S ?( T), and G ?( T) - H ?(0), over the temperature range from T ? 0 to 350-370 K. The energy of combustion of 5-vinyltetrazole and poly-5-vinyltetrazole was measured in an isothermic-shell static bomb calorimeter. The standard enthalpies of combustion ? c H ? and thermodynamic characteristics of formation ?f H ?, ?f S ?, and ?f G ? at 298.15 K and p = 0.1 MPa were calculated. The results were used to determine the thermodynamic characteristics of polymerization of 5-vinyltetrazole over the temperature range from T ? 0 to 350 K.

  8. Structural, electronic, optical and thermodynamic properties of NaxRb1-xH and NaxK1-xH alloys

    NASA Astrophysics Data System (ADS)

    Fatmi, Messaoud; Ghebouli, Brahim; Ghebouli, Mohamed Amine; Bouhemadou, Abdelmadjid; Binomran, Saad

    2012-01-01

    A theoretical study of the structural, electronic, optical and thermodynamic properties of NaxRb1-xH and NaxK1-xH ternary alloys in NaCl phase has been carried out using the first-principles method. We modeled the alloys at some selected compositions with ordered structures described in terms of periodically repeated supercells. The dependences on the composition of the lattice constant, band gap, dielectric constant, refractive index, Debye temperature, mixing entropy and heat capacities were analyzed for x=0, 0.25, 0.50, 0.75 and 1. The lattice constants of NaxRb1-xH and NaxK1-xH exhibit a marginal deviation from Vegard's law. A strong deviation of the bulk modulus from linear concentration dependence was observed for both alloys. We found that the composition dependence of the energy band gap is highly non linear and the large bowing coefficient for NaxRb1-xH is sensitive to the composition. Using the approach of Zunger and co-workers, the microscopic origins of the gap bowing were detailed and explained. The thermodynamic stability of these alloys was investigated by calculating the phase diagram. The thermal effect on some macroscopic properties was investigated using the quasi-harmonic Debye model. There is a good agreement between our results and the available experimental data for the binary compounds, which is a support for those of the ternary alloys that we report for the first time.

  9. Investigation of thermodynamic properties of poly(methyl methacrylate-co-n-butylacrylate-co-cyclopentyl styryl-polyhedral oligomeric silsesquioxane) by inverse gas chromatography.

    PubMed

    Zou, Qi-Chao; Zhang, Shi-Ling; Wang, Shi-Min; Wu, Li-Min

    2006-10-01

    The thermodynamic properties of poly(methyl methacrylate-co-butyl acrylate-co-cyclo -pentylstyryl polyhedral oligomeric silsesquioxane) (poly(MMA-co-BA-co-styryl-POSS)) were investigated by means of inverse gas chromatography (IGC) using 20 different kinds of solvents as the probes. Some thermodynamic parameters, such as molar heats of sorption, weight fraction activity coefficient, Flory-Huggins interaction parameter, partial molar heats of mixing and solubility parameter were obtained to judge the interactions between POSS-contained polymers and solvents and the solubility of the polymers in these solvents. It was found that acetates, aromatic hydrocarbons and hydrocarbon halides were good solvents, n-hexane, ethanol, n-propanol, n-butanol and n-pentanol were moderate solvents, while n-heptane, n-octane, n-nonane, n-decane and methanol were poor solvents for all POSS-contained polymers within the experimental temperature range. Incorporation of POSS in polymer increased the solubility of polymers in solvents, and the more the POSS in polymer was, the better the solubility was and stronger the hydrogen bonding interaction was, but the POSS content in polymers seemed to have no obvious influence on the solubility parameter of polymers. PMID:16846607

  10. Similarity and contrasts between thermodynamic properties at the critical point of liquid alkali metals and of electron-hole droplets

    E-print Network

    F. E. Leys; N. H. March; G. G. N. Angilella; M. L. Zhang

    2004-05-06

    The recent experimental study by means of time-resolved luminescence measurements of an electron-hole liquid (EHL) in diamond by Shimano et al. [Phys. Rev. Lett. 88 (2002) 057404] prompts us to compare and contrast critical temperature T_c and critical density n_c relations in liquid alkali metals with those in electron-hole liquids. The conclusion drawn is that these systems have similarities with regard to critical properties. In both cases the critical temperature is related to the cube root of the critical density. The existence of this relation is traced to Coulomb interactions and to systematic trends in the dielectric constant of the electron-hole systems. Finally a brief comparison between the alkalis and EHLs of the critical values for the compressibility ratio Z_c is also given.

  11. Thermodynamical properties of an antiferromagnetic Heisenberg spin system on a fractal lattice of dimension between one and two

    NASA Astrophysics Data System (ADS)

    Tomczak, P.

    1996-01-01

    The Suzuki-Takano quantum decimation technique is applied to the antiferromagnetic, nearest-neighbor, frustrated Heisenberg spin-1/2 system attached to a lattice with dimension d=ln3/ln2. Some thermodynamical functions are calculated. The temperature dependence of the specific heat is very similar to that obtained for the Heisenberg spin system on a kagomé lattice.

  12. A Survey of the Role of Thermodynamics and Transport Properties in Chemical Engineering University Education in Europe and the USA

    ERIC Educational Resources Information Center

    Ahlstrom, Peter; Aim, Karel; Dohrn, Ralf; Elliott, J. Richard; Jackson, George; Jaubert, Jean-Noel; Macedo, Eugenia A.; Pokki, Juha-Pekka; Reczey, Kati; Victorov, Alexey; Zilnik, Ljudmila Fele; Economou, Ioannis G.

    2010-01-01

    A survey on the teaching of thermodynamics and transport phenomena in chemical engineering curricula in European and US Universities was performed and results are presented here. Overall, 136 universities and colleges responded to the survey, out of which 81 from Europe and 55 from the USA. In most of the institutions responding at least two…

  13. First-principles investigation of thermodynamic, elastic and electronic properties of Al{sub 3}V and Al{sub 3}Nb intermetallics under pressures

    SciTech Connect

    Chen, Zhe; Zhang, Peng; Chen, Dong; Wu, Yi; Wang, Mingliang Ma, Naiheng; Wang, Haowei

    2015-02-28

    The thermodynamic, elastic, and electronic properties of D0{sub 22}-type Al{sub 3}V and Al{sub 3}Nb intermetallics were studied using the first-principle method. The results showed the pressure has profound effects on the structural, mechanical and electronic properties in both Al{sub 3}V and Al{sub 3}Nb. Thermodynamically, the formation enthalpies for Al{sub 3}V and Al{sub 3}Nb were derived, which agreed well with available experimental and theoretical values. Comparably, Al{sub 3}Nb was a more stable phase with the more negative H{sub f} than Al{sub 3}V. Mechanically, the calculated elastic constants showed linearly increasing tendencies, and satisfied the Born's criteria from 0–20?GPa, indicating the mechanically stability of Al{sub 3}V and Al{sub 3}Nb under this pressure range. Further, the mechanical parameters (i.e., bulk modulus (B), shear modulus (G), and Young's modulus (E)) were derived using the Voigt-Reuss-Hill (VRH) method, and in good agreement with available experimental results at the ground state. All these parameters presented the linearly increasing dependences on the external pressure. The B/G ratios and Poisson's ratio indicated that the Al{sub 3}V and Al{sub 3}Nb crystals should exhibit brittle behavior at 0–20?GPa. Additionally, the bulk modulus can be obtained through fitting the Birch-Murnaghan equation (B{sub 0}), computing by VRH method (B{sub H}), and deriving from the elastic theory (B{sub relax}) in both intermetallics. The uniformity of these calculated bulk moduli in each compound exhibited the excellent reliability and self-consistency. In addition, Debye temperature was estimated from the average sound velocity. The Debye temperature showed an increasing dependence on the pressures. Finally, through density of states analysis, Al{sub 3}V and Al{sub 3}Nb were suggested to possess naturally metallic behavior. Under pressures, it was noted that the shapes of peaks and pseudogaps exhibited relative few changes, suggesting Al{sub 3}V and Al{sub 3}Nb has kept structurally stable up to 20 GPa. At zero pressure, Al{sub 3}Nb was considered as a more structurally stable phase with the more number of bonding electrons per atom than Al{sub 3}V. This conclusion was in consistent with the one drawn from the thermodynamic analysis.

  14. Speciation and thermodynamic properties for cobalt chloride complexes in hydrothermal fluids at 35-440 °C and 600 bar: An in-situ XAS study

    NASA Astrophysics Data System (ADS)

    Liu, Weihua; Borg, Stacey J.; Testemale, Denis; Etschmann, Barbara; Hazemann, Jean-Louis; Brugger, Joël

    2011-03-01

    Aqueous Co(II) chloride complexes play a crucial role in cobalt transport and deposition in ore-forming hydrothermal systems, ore processing plants, and in the corrosion of special Co-bearing alloys. Reactive transport modelling of cobalt in hydrothermal fluids relies on the availability of thermodynamic properties for Co complexes over a wide range of temperature, pressure and salinity. Synchrotron X-ray absorption spectroscopy was used to determine the speciation of cobalt(II) in 0-6 m chloride solutions at temperatures between 35 and 440 °C at a constant pressure of 600 bar. Qualitative analysis of XANES spectra shows that octahedral species predominate in solution at 35 °C, while tetrahedral species become increasingly important with increasing temperature. Ab initio XANES calculations and EXAFS analyses suggest that in high temperature solutions the main species at high salinity (Cl:Co >> 2) is CoCl 42-, while a lower order tetrahedral complex, most likely CoCl 2(H 2O) 2(aq), predominates at low salinity (Cl:Co ratios ˜2). EXAFS analyses further revealed the bonding distances for the octahedral Co(H 2O) 62+ ( octCo-O = 2.075(19) Å), tetrahedral CoCl 42- ( tetCo-Cl = 2.252(19) Å) and tetrahedral CoCl 2(H 2O) 2(aq) ( tetCo-O = 2.038(54) Å and tetCo-Cl = 2.210(56) Å). An analysis of the Co(II) speciation in sodium bromide solutions shows a similar trend, with tetrahedral bromide complexes becoming predominant at higher temperature/salinity than in the chloride system. EXAFS analysis confirms that the limiting complex at high bromide concentration at high temperature is CoBr 42-. Finally, XANES spectra were used to derive the thermodynamic properties for the CoCl 42- and CoCl 2(H 2O) 2(aq) complexes, enabling thermodynamic modelling of cobalt transport in hydrothermal fluids. Solubility calculations show that tetrahedral CoCl 42- is responsible for transport of cobalt in hydrothermal solutions with moderate chloride concentration (˜2 m NaCl) at temperatures of 250 °C and higher, and both cooling and dilution processes can cause deposition of cobalt from hydrothermal fluids.

  15. First-principles investigation of thermodynamic, elastic and electronic properties of Al3V and Al3Nb intermetallics under pressures

    NASA Astrophysics Data System (ADS)

    Chen, Zhe; Zhang, Peng; Chen, Dong; Wu, Yi; Wang, Mingliang; Ma, Naiheng; Wang, Haowei

    2015-02-01

    The thermodynamic, elastic, and electronic properties of D022-type Al3V and Al3Nb intermetallics were studied using the first-principle method. The results showed the pressure has profound effects on the structural, mechanical and electronic properties in both Al3V and Al3Nb. Thermodynamically, the formation enthalpies for Al3V and Al3Nb were derived, which agreed well with available experimental and theoretical values. Comparably, Al3Nb was a more stable phase with the more negative Hf than Al3V. Mechanically, the calculated elastic constants showed linearly increasing tendencies, and satisfied the Born's criteria from 0-20 GPa, indicating the mechanically stability of Al3V and Al3Nb under this pressure range. Further, the mechanical parameters (i.e., bulk modulus (B), shear modulus (G), and Young's modulus (E)) were derived using the Voigt-Reuss-Hill (VRH) method, and in good agreement with available experimental results at the ground state. All these parameters presented the linearly increasing dependences on the external pressure. The B/G ratios and Poisson's ratio indicated that the Al3V and Al3Nb crystals should exhibit brittle behavior at 0-20 GPa. Additionally, the bulk modulus can be obtained through fitting the Birch-Murnaghan equation (B0), computing by VRH method (BH), and deriving from the elastic theory (Brelax) in both intermetallics. The uniformity of these calculated bulk moduli in each compound exhibited the excellent reliability and self-consistency. In addition, Debye temperature was estimated from the average sound velocity. The Debye temperature showed an increasing dependence on the pressures. Finally, through density of states analysis, Al3V and Al3Nb were suggested to possess naturally metallic behavior. Under pressures, it was noted that the shapes of peaks and pseudogaps exhibited relative few changes, suggesting Al3V and Al3Nb has kept structurally stable up to 20 GPa. At zero pressure, Al3Nb was considered as a more structurally stable phase with the more number of bonding electrons per atom than Al3V. This conclusion was in consistent with the one drawn from the thermodynamic analysis.

  16. Molecular structure, vibrational spectroscopic, hyperpolarizability, natural bond orbital analysis, frontier molecular orbital analysis and thermodynamic properties of 2,3,4,5,6-pentafluorophenylacetic acid

    NASA Astrophysics Data System (ADS)

    Balachandran, V.; Karunakaran, V.

    2014-06-01

    The FT-IR (4000-400 cm-1) and FT-Raman spectra (3500-100 cm-1) of 2,3,4,5,6-pentafluorophenylacetic acid (PAA) have been recorded. Density functional theory calculation with LSDA/6-31+G(d,p) and B3LYP/6-31+G(d,p) basis sets have been used to determine ground state molecular geometries (bond lengths and bond angles), harmonic vibrational frequencies, infrared intensities, Raman intensities and bonding features of the title compound. The assignments of the vibrational spectra have been carried out with the help of normal coordinate analysis (NCA) following the scaled quantum mechanical force field (SQMFF) methodology. The first order hyperpolarizability (?0) and related properties (?, ?0 and ??) of PAA are calculated using B3LYP/6-31+G(d,p) method on the finite-field approach. The calculated first hyperpolarizability shows that the molecule is an attractive molecule for future applications in non-linear optics. The stability of molecule has been analyzed by using NBO analysis. The calculated HOMO and LUMO energies show that charge transfer occurs within this molecule. Mulliken population analysis on atomic charges is also calculated. Thermodynamic properties (heat capacity, enthalpy, Gibb's free energy and entropy) of the title compound at different temperatures were calculated.

  17. Thermodynamic properties of water molecules in the presence of cosolute depend on DNA structure: a study using grid inhomogeneous solvation theory.

    PubMed

    Nakano, Miki; Tateishi-Karimata, Hisae; Tanaka, Shigenori; Tama, Florence; Miyashita, Osamu; Nakano, Shu-Ichi; Sugimoto, Naoki

    2015-12-01

    In conditions that mimic those of the living cell, where various biomolecules and other components are present, DNA strands can adopt many structures in addition to the canonical B-form duplex. Previous studies in the presence of cosolutes that induce molecular crowding showed that thermal stabilities of DNA structures are associated with the properties of the water molecules around the DNAs. To understand how cosolutes, such as ethylene glycol, affect the thermal stability of DNA structures, we investigated the thermodynamic properties of water molecules around a hairpin duplex and a G-quadruplex using grid inhomogeneous solvation theory (GIST) with or without cosolutes. Our analysis indicated that (i) cosolutes increased the free energy of water molecules around DNA by disrupting water-water interactions, (ii) ethylene glycol more effectively disrupted water-water interactions around Watson-Crick base pairs than those around G-quartets or non-paired bases, (iii) due to the negative electrostatic potential there was a thicker hydration shell around G-quartets than around Watson-Crick-paired bases. Our findings suggest that the thermal stability of the hydration shell around DNAs is one factor that affects the thermal stabilities of DNA structures under the crowding conditions. PMID:26538600

  18. Thermodynamic properties of water molecules in the presence of cosolute depend on DNA structure: a study using grid inhomogeneous solvation theory

    PubMed Central

    Nakano, Miki; Tateishi-Karimata, Hisae; Tanaka, Shigenori; Tama, Florence; Miyashita, Osamu; Nakano, Shu-ichi; Sugimoto, Naoki

    2015-01-01

    In conditions that mimic those of the living cell, where various biomolecules and other components are present, DNA strands can adopt many structures in addition to the canonical B-form duplex. Previous studies in the presence of cosolutes that induce molecular crowding showed that thermal stabilities of DNA structures are associated with the properties of the water molecules around the DNAs. To understand how cosolutes, such as ethylene glycol, affect the thermal stability of DNA structures, we investigated the thermodynamic properties of water molecules around a hairpin duplex and a G-quadruplex using grid inhomogeneous solvation theory (GIST) with or without cosolutes. Our analysis indicated that (i) cosolutes increased the free energy of water molecules around DNA by disrupting water–water interactions, (ii) ethylene glycol more effectively disrupted water–water interactions around Watson–Crick base pairs than those around G-quartets or non-paired bases, (iii) due to the negative electrostatic potential there was a thicker hydration shell around G-quartets than around Watson–Crick-paired bases. Our findings suggest that the thermal stability of the hydration shell around DNAs is one factor that affects the thermal stabilities of DNA structures under the crowding conditions. PMID:26538600

  19. Influence of structure and thermodynamic stability on electronic properties of two-dimensional SiC, SiGe, and GeC alloys

    NASA Astrophysics Data System (ADS)

    Guilhon, I.; Teles, L. K.; Marques, M.; Pela, R. R.; Bechstedt, F.

    2015-08-01

    The energetics and thermodynamic properties of two-dimensional binary graphene-like alloys made from graphene, silicene, or germanene are investigated by combining first-principles total energy calculations, and a statistical approach to account for disorder and composition effects. For the electronic properties the calculations are performed within the GGA-1/2 approach for an approximate quasiparticle bands. We derive lattice constants, first-neighbor distances, and buckling parameters as a function of composition x . The Si1 -xGex system is the only stable random alloy at usual growth temperatures. For Ge1 -xCx , we observe strong distortions of the lattice making the random configurations less favorable and leading to a pronounced tendency for phase separation. The situation for Si1 -xCx alloys is completely different. An ordered structure with composition x =0.5 is stable up to T ?1000 K, while intermediate compositions are mainly realized by silicongraphene and graphene or silicene. The ordering and decomposition effects have a strong influence on the average fundamental energy gap versus composition. Whereas large gaps appear for Si1 -xCx systems they almost vanish for Ge1 -xSix and Ge1 -xCx . Moreover, the dependence of the Si1 -xCx energy gap on growth temperature is also obtained. The results can be very useful for chemical vapor deposition growth of these materials.

  20. The thermodynamic properties of 2-ethylhexyl acrylate over the temperature range from T ? 0 to 350 K

    NASA Astrophysics Data System (ADS)

    Kulagina, T. G.; Samosudova, Ya. S.; Letyanina, I. A.; Sevast'yanov, E. V.; Smirnova, N. N.; Smirnova, L. A.; Mochalova, A. E.

    2012-05-01

    The temperature dependence of the heat capacity C {/p o}= f( T) 2 of 2-ethylhexyl acrylate was studied in an adiabatic vacuum calorimeter over the temperature range 6-350 K. Measurement errors were mainly of 0.2%. Glass formation and vitreous state parameters were determined. An isothermic shell calorimeter with a static bomb was used to measure the energy of combustion of 2-ethylhexyl acrylate. The experimental data were used to calculate the standard thermodynamic functions C {/p o}( T), H o( T)- H o(0), S o( T)- S o(0), and G o( T)- H o(0) of the compound in the vitreous and liquid states over the temperature range from T ? 0 to 350 K, the standard enthalpies of combustion ?c H o, and the thermodynamic characteristics of formation ?f H o, ?f S o, and ?f G o at 298.15 K and p = 0.1 MPa.

  1. On the radiative and thermodynamic properties of the Cosmic Microwave Background radiation using COBE FIRAS instrument data

    E-print Network

    Fisenko, Anatoliy I

    2014-01-01

    Use formulas to describe the monopole and dipole spectra of the Cosmic Microwave Background (CMB) radiation, the exact expressions for the temperature dependences of the radiative and thermodynamic functions, such as the total radiation power per unit area, total energy density, number density of photons, Helmholtz free energy density, entropy density, heat capacity at constant volume, pressure, enthalpy density, and internal energy density in the finite range of frequencies are obtained. Since the dependence of temperature upon the redshift z is known, the obtained expressions can be simply presented in z representation. Utilizing experimental data for the monopole and dipole spectra measured by the COBE FIRAS instrument in the 60 - 600 GHz frequency interval at the temperature T = 2.728 K, the values of the radiative and thermodynamic functions, as well as the radiation density constant a and the Stefan-Boltzmann constant are calculated. In the case of the dipole spectrum, the constants a and the Stefan-Bol...

  2. Group additivity equations of state for calculating the standard molal thermodynamic properties of aqueous organic species at elevated temperatures and pressures

    SciTech Connect

    Amend, J.P.; Helgeson, H.C.

    1997-01-01

    Group additivity equations of state for aqueous organic molecules have been generated by combining the revised Helgeson-Kirkham-Howers (HKF) equations of state with experimental values of the standard molal properties of aqueous alkanes, alkanols, alkylbenzenes, carboxylic acids, amides, and amines. Equations of state parameters for the groups represented by -CH{sub 2}-, -CH{sub 3}, -CHCH{sub 3}, -C{sub 6}H{sub 5}, -CH{sub 2}OH, -COOH, -CONH{sub 2}, and -CH{sub 2}NH{sub 2} were determined by regression of the experimental data. This procedure permits calculation of the standard molal thermodynamic properties of these groups at elevated temperatures and pressures. Although curves representing the apparent standard molal Gibbs free energies ({Delta}G{degrees}) and enthalpies ({Delta}H{degrees}) of formation, and the standard molal entropies (S{degrees}) of the groups as a function of temperature and pressure are respectively similar for each of them, the temperature dependence of the standard molal heat capacities (C{degrees}{sub P}) and volumes (V{degrees}) of a number of the groups are quite different from one another. For example, the standard molal heat capacities of the hydrocarbon groups minimize with increasing temperature, but those of -CH{sub 2}OH and -CH{sub 2}NH{sub 2} maximize. Computed values of {Delta}G{degrees}, {Delta}H{degrees}, S{degrees}, C{degrees}{sub P}, V{degrees}, and the equations of state parameters for the various groups were used together with group additivity relations to generate corresponding values of these properties for aqueous n-alkanes, 2-methylalkanes, n-alkylbenzenes, n-alkanols, n-carboxylic acids, n-amides, and n-amines at temperatures {le} 250{degrees}C and pressures {le} 1 kbar. 159 refs., 25 figs., 20 tabs.

  3. Influence of particle size and water coverage on the thermodynamic properties of water confined on the surface of SnO2 cassiterite nanoparticles

    SciTech Connect

    Spencer, Elinor; Ross, Dr. Nancy; Parker, Stewart F.; Kolesnikov, Alexander I; Woodfield, Brian; Woodfield, K; Rytting, M; Boerio-Goates, Juliana; Navrotsky, Alexandra

    2011-01-01

    Inelastic neutron scattering (INS) data for SnO2 nanoparticles of three different sizes and varying hydration levels are presented. Data were recorded on five nanoparticle samples that had the following compositions: 2 nm SnO2*0.82H2O, 6 nm SnO2*0.055H2O, 6 nm SnO2*0.095H2O, 20 nm SnO2*0.072H2O, and 20 nm SnO2*0.092H2O. The isochoric heat capacity and vibrational entropy values at 298 K for the water confined on the surface of these nanoparticles were calculated from the vibrational density of states that were extracted from the INS data. This study has shown that the hydration level of the SnO2 nanoparticles influences the thermodynamic properties of the water layers and, most importantly, that there appears to be a critical size limit for SnO2 between 2 and 6 nm below which the particle size also affects these properties and above which it does not. These results have been compared with those for isostructural rutile-TiO2 nanoparticles [TiO2*0.22H2O and TiO2*0.37H2O], which indicated that water on the surface of TiO2 nanoparticles is more tightly bound and experiences a greater degree of restricted motion with respect to water on the surface of SnO2 nanoparticles. This is believed to be a consequence of the difference in chemical composition, and hence surface properties, of these metal oxide nanoparticles.

  4. Calculation of the thermodynamic properties at elevated temperatures and pressures of saturated and aromatic high molecular weight solid and liquid hydrocarbons in kerogen, bitumen, petroleum, and other organic matter of biogeochemical interest

    NASA Astrophysics Data System (ADS)

    Richard, Laurent; Helgeson, Harold C.

    1998-12-01

    To supplement the relatively sparse set of calorimetric data available for the multitude of high molecular weight organic compounds of biogeochemical interest, group additivity algorithms have been developed to estimate heat capacity power function coefficients and the standard molal thermodynamic properties at 25°C and 1 bar of high molecular weight compounds in hydrocarbon source rocks and reservoirs, including crystalline and liquid isoprenoids, steroids, tricyclic diterpenoids, hopanoids, and polynuclear aromatic hydrocarbons. A total of ninety-six group contributions for each coefficient and property were generated from the thermodynamic properties of lower molecular weight reference species for which calorimetric data are available in the literature. These group contributions were then used to compute corresponding coefficients and properties for ˜360 representative solid and liquid high molecular weight compounds in kerogen, bitumen, and petroleum for which few or no experimental data are available. The coefficients and properties of these high molecular weight compounds are summarized in tables, together with those of the groups and reference species from which they were generated. The tabulated heat capacity power function coefficients and standard molal thermodynamic properties at 25°C and 1 bar include selected crystalline and liquid regular, irregular and highly branched isoprenoids, tricyclic diterpanes, 17?(H)- and 17?(H)-hopanes, 5?(H),14?(H)-, 5?(H),14?(H)-, 5?(H),14?(H)-, and 5?(H),14?(H)-steranes, double ether- and ester-bonded n-alkanes, and various polynuclear aromatic hydrocarbons, including methylated biphenyls, naphthalenes, phenanthrenes, anthracenes, pyrenes, and chrysenes. However, corresponding coefficients and properties for many more saturated and unsaturated high molecular weight hydrocarbons can be estimated from the equations of state group additivity algorithms. Calculations of this kind permit comprehensive thermodynamic description of the chemical evolution of organic matter with increasing depth in sedimentary basins.

  5. A theoretical study of the thermodynamic properties of YMgX{sub 4} (X=Co, Ni, Cu) compounds

    SciTech Connect

    Li, Ruizi; Shen, Jiang; Tian, Fuyang

    2014-09-15

    The stability, electronic structures, elastic and thermal properties of the ternary YMgX{sub 4} (X=Co, Ni, Cu) compounds are investigated by first principle calculations in combination with the quasi-harmonic Debye model. The three compounds are predicted to be stable according to the formation enthalpies (?H), elastic constants (c{sub ij}) and phonon dispersion models. The elastic constants and polycrystalline elastic moduli reveal the relatively low anisotropy of these compounds. The electronic structures and bonding characters are analyzed by the electron densities of states and difference charge densities in the (110) plane. The comparisons between the phonon density of state and the quasi-harmonic Debye model imply the heat capacities (C{sub v}) and vibrational entropies (S) are close for YMgCo{sub 4} and YMgCu{sub 4}, whereas large deviation for YMgNi{sub 4}. A possible reason is that YMgNi{sub 4} has the slightly strong directional bondings, relative to YMgCo{sub 4} and YMgCu{sub 4}.

  6. Feature Article: Thermodynamic properties from ab-initio calculations: New theoretical developments, and applications to various materials systems

    NASA Astrophysics Data System (ADS)

    Fähnle, Manfred; Drautz, Ralf; Lechermann, Frank; Singer, Reinhard; Diaz-Ortiz, Alejandro; Dosch, Helmut

    2005-05-01

    The cover picture from the Feature Article [1] depicts the calculated landscape of lowest formation energies for the ternary compound system Ni-Fe-Al. The figure shows for each composition the difference in the formation energy (in meV/atom) for the respective homogeneous configuration with lowest energy on the bcc and the fcc parent lattice. The phases on the fcc lattice dominate the Ni- and Al-rich regions of the Gibbs triangle.The first author Manfred Fähnle is Professor at the University of Stuttgart and member of the theory group of the department of Prof. Schütz at the Max-Planck-Institut für Metallforschung in Stuttgart. In 1980 he was awarded with the Otto-Hahn medal of the Max-Planck Society and in 1985 he received the Academy Award for Physics of the University of Göttingen. His present research interests are the static and dynamic properties of bulk and nanostructured magnetic systems, as well as the ab-initio statistical mechanics of alloys.

  7. Atomistic Calculations of the Effect of Minor Actinides on Thermodynamic and Kinetic Properties of UO{sub 2{+-}x}

    SciTech Connect

    Deo, Chaitanya; Adnersson, Davis; Battaile, Corbett; uberuaga, Blas

    2012-10-30

    The team will examine how the incorporation of actinide species important for mixed oxide (MOX) and other advanced fuel designs impacts thermodynamic quantities of the host UO{sub 2} nuclear fuel and how Pu, Np, Cm and Am influence oxygen mobility. In many cases, the experimental data is either insufficient or missing. For example, in the case of pure NpO2, there is essentially no experimental data on the hyperstoichiometric form it is not even known if hyperstoichiometry NpO{sub 2{+-}x} is stable. The team will employ atomistic modeling tools to calculate these quantities

  8. PROPERTY MANUAL Berkeley Laboratory Property Management

    E-print Network

    Knowles, David William

    PROPERTY MANUAL Issued by Berkeley Laboratory Property Management Lawrence Berkeley National Berkeley Laboratory policies is available in the Regulations and Procedures Manual (RPM). · Overview of property entrusted to Lawrence Berkeley National Laboratory (Berkeley Laboratory) by the U.S. Department

  9. Thermodynamic and transport properties of single crystalline RCo2Ge2 (R=Y, La–Nd, Sm–Tm)

    SciTech Connect

    Kong, Tai; Cunningham, Charles E.; Taufour, Valentin; Budko, Sergey L.; Buffon, Malinda L.C.; Lin, Xiao; Emmons, Heather; Canfield, Paul C.

    2014-05-01

    Single crystals of RCo2Ge2 (R=Y, La–Nd, Sm–Tm) were grown using a self-flux method and were characterized by room-temperature powder X-ray diffraction; anisotropic, temperature and field dependent magnetization; temperature and field dependent, in-plane resistivity; and specific heat measurements. In this series, the majority of the moment-bearing members order antiferromagnetically; YCo2Ge2 and LaCo2Ge2 are non-moment-bearing. Ce is trivalent in CeCo2Ge2 at high temperatures, and exhibits an enhanced electronic specific heat coefficient due to the Kondo effect at low temperatures. In addition, CeCo2Ge2 shows two low-temperature anomalies in temperature-dependent magnetization and specific heat measurements. Three members (R=Tb–Ho) have multiple phase transitions above 1.8 K. Eu appears to be divalent with total angular momentum L =0. Both EuCo2Ge2 and GdCo2Ge2 manifest essentially isotropic paramagnetic properties consistent with J =S =7/2. Clear magnetic anisotropy for rare-earth members with finite L was observed, with ErCo2Ge2 and TmCo2Ge2 manifesting planar anisotropy and the rest members manifesting axial anisotropy. The experimentally estimated crystal electric field (CEF) parameters B 20 were calculated from the anisotropic paramagnetic ? ab and ? c values and follow a trend that agrees well with theoretical predictions. The ordering temperatures, TNTN, as well as the polycrystalline averaged paramagnetic Curie–Weiss temperature, ?avg, for the heavy rare-earth members deviate from the de Gennes scaling, as the magnitude of both is the highest for Tb, which is sometimes seen for extremely axial systems. Except for SmCo2Ge2, metamagnetic transitions were observed at 1.8 K for all members that ordered antiferromagnetically.

  10. Structures, spectroscopic and thermodynamic properties of U?On (n = 0 ? 2, 4) molecules: a density functional theory study.

    PubMed

    Li, Peng; Niu, Wen-Xia; Gao, Tao; Wang, Fan; Jia, Ting-Ting; Meng, Da-Qiao; Li, Gan

    2013-12-01

    The equilibrium structures, spectroscopic and thermodynamic parameters [entropy (S), internal energy (E), heat capacity (C p)] of U?, U?O, U?O? and U?O? uranium oxide molecules were investigated systematically using density functional theory (DFT). Our computations indicated that the ground electronic state of U? is the septet state and the equilibrium bond length is 2.194 Å; the ground electronic state of U?O and U?O? were found to be X³? and X³?(g) with stable C(?v) and D(?h) linear structures, respectively. The bridge-bonded structure with D(2h) symmetry and X³B?(g) state is the most stable configuration for the U?O? molecule. Mulliken population analyses show that U atoms always lose electrons to become the donor and O atoms always obtain electrons as the acceptor. Molecular orbital analyses demonstrated that the frontier orbitals of the title molecules were contributed mostly by 5f atomic orbitals of U atoms. Vibrational frequencies analyses indicate that the maximum absorption peaks stem from the stretching mode of U-O bonds in U?O, U?O? and U?O?. In addition, thermodynamic data of U?O(n) (n = 0 ? 4) molecules at elevated temperatures of 293.0 K to 393.0 K was predicted. PMID:24253320

  11. Thermal equation of state to 33.5 GPa and 1673 K and thermodynamic properties of tungsten

    NASA Astrophysics Data System (ADS)

    Litasov, Konstantin D.; Gavryushkin, Pavel N.; Dorogokupets, Peter I.; Sharygin, Igor S.; Shatskiy, Anton; Fei, Yingwei; Rashchenko, Sergey V.; Seryotkin, Yury V.; Higo, Yiji; Funakoshi, Kenichi; Ohtani, Eiji

    2013-04-01

    A comprehensive P-V-T dataset for bcc-tungsten was obtained for pressures up to 33.5 GPa and temperatures 300-1673 K using MgO and Au pressure scales. The thermodynamic analysis of these data was performed using high-temperature (HT) and Mie-Grüneisen-Debye (MGD) relations combined with the Vinet equations of state (EOS) for room-temperature isotherm and the newly proposed Kunc-Einstein (KE) EOS. The KE EOS allowed calibration of W thermodynamic parameters to the pressures of at least 300 GPa and temperatures up to 4000 K with minor uncertainties (<1% in calculated volume of W). A detailed analysis of room-temperature compression data with Vinet EOS yields V0 = 31.71 ± 0.02 Å3, KT = 308 ± 1 GPa, and KT' = 4.20 ± 0.05. Estimated thermoelastic parameters for HT include (?KT/?T)P = -0.018 ± 0.001 GPa/K and thermal expansion ? = a0 + a1T with a0 = 1.35 (±0.04) × 10-5 K-1 and a1 = 0.21 (±0.05) × 10-8 K-2. Fitting to the MGD relation yielded ?0 = 1.81 ± 0.02 and q = 0.71 ± 0.02 with the Debye temperature (?0,) fixed at 370-405 K. The parameters for KE EOS include two Einstein temperatures, ?E1o = 314 K and ?E2o = 168 K, Grüneisen parameter at ambient condition ?0 = 1.67 and infinite compression ?? = 0.66, with ? = 1.16 (which is a power-mode parameter in the Grüneisen equation), anharmonicity (m = 3.57) and electronic (g = 0.11) equivalents of the Grüneisen parameter, and additional parameters for intrinsic anharmonicity, a0 = 6.2 × 10-5 K-1, and electronic contribution, e0 = 4.04 × 10-5 K-1 to the free energy. Fixed parameters include k = 2 in KE EOS and mE1 = mE2 = 1.5 in expression for Einstein temperature. Present analysis should represent the best fit of the experimental data for W and can be used for a variety of thermodynamic calculations for W and W-containing systems including phase diagrams, chemical reactions, and electronic structure.

  12. Melting and thermodynamic properties of pyrope (Mg sub 3 Al sub 2 Si sub 3 O sub 12 )

    SciTech Connect

    Tequi, C.; Neuville, D.R.; Richet, P. ); Robie, R.A.; Hemingway, B.S. )

    1991-04-01

    The heat capacity of Mg{sub 3}Al{sub 2}Si{sub 3}O{sub 12} glass has been measured from 10 to 1000 K by adiabatic and differential scanning calorimetry. The heat capacity of crystalline pyrope has been determined from drop-calorimetry measurements between 820 and 1300 K. From these and previously published results a consistent set of thermodynamic data is presented for pyrope and Mg{sub 3}Al{sub 2}Si{sub 3}O{sub 12} glass and liquid for the interval 0-2000 K. The enthalpy of fusion at 1570 {plus minus} 30 K, the metastable congruent 1-bar melting point, is 241 {plus minus} 12 kJ/mol.

  13. Applications in environmental bioinorganic: Nutritional and ultrastructural evaluation and calculus of thermodynamic and structural properties of metal-oxalate complexes.

    PubMed

    Tolentino, Terezinha Alves; Bertoli, Alexandre Carvalho; dos Santos Pires, Maíra; Carvalho, Ruy; Labory, Claudia Regina Gontijo; Nunes, Janaira Santana; Bastos, Ana Rosa Ribeiro; de Freitas, Matheus Puggina

    2015-11-01

    Lead (Pb) is known by its toxicity both for animals and plants. In order to evaluate its toxicity, plants of Brachiaria brizantha were cultivated on nutritive solution of Hoagland during 90 days and submitted to different concentrations of Pb. The content of macro and micronutrients was evaluated and there was a reduction on root content of Ca, besides the lowest dosages of Pb had induced an increase of N, S, Mn, Cu, Zn and Fe. The cell ultrastructure of leaves and roots were analyzed by transmission electronic microscopy (TEM). Among the main alterations occurred there were invaginations on cell walls, the presence of crystals on the root cells, accumulation of material on the interior of cells and vacuolar compartmentalization. On the leaves the degradation of chloroplasts was observed, as well as the increase of vacuoles. Structures for the formation of oxalate crystals were proposed through molecular modeling and thermodynamic stability. Calculi suggest the formation of highly stable metal-oxalate complexes. PMID:26099826

  14. Experimentally Determined Standard Thermodynamic Properties of Synthetic MgSO4·4H2O (Starkeyite) and MgSO4·3H2O: A Revised Internally Consistent Thermodynamic Data Set for Magnesium Sulfate Hydrates

    PubMed Central

    Majzlan, Juraj; Benisek, Artur; Dachs, Edgar; Steiger, Michael; Fortes, A. Dominic; Marler, Bernd

    2012-01-01

    Abstract The enthalpies of formation of synthetic MgSO4·4H2O (starkeyite) and MgSO4·3H2O were obtained by solution calorimetry at T=298.15?K. The resulting enthalpies of formation from the elements are \\documentclass{aastex}\\usepackage{amsbsy}\\usepackage{amsfonts}\\usepackage{amssymb}\\usepackage{bm}\\usepackage{mathrsfs}\\usepackage{pifont}\\usepackage{stmaryrd}\\usepackage{textcomp}\\usepackage{portland, xspace}\\usepackage{amsmath, amsxtra}\\pagestyle{empty}\\DeclareMathSizes{10}{9}{7}{6}\\begin{document}$$\\Delta_{ \\rm f}H^0_{298}$$\\end{document} (starkeyite)=?2498.7±1.1?kJ·mol?1 and \\documentclass{aastex}\\usepackage{amsbsy}\\usepackage{amsfonts}\\usepackage{amssymb}\\usepackage{bm}\\usepackage{mathrsfs}\\usepackage{pifont}\\usepackage{stmaryrd}\\usepackage{textcomp}\\usepackage{portland, xspace}\\usepackage{amsmath, amsxtra}\\pagestyle{empty}\\DeclareMathSizes{10}{9}{7}{6}\\begin{document}$$\\Delta_{ \\rm f}H^0_{298}$$\\end{document} (MgSO4·3H2O)=?2210.3±1.3?kJ·mol?1. The standard entropy of starkeyite was derived from low-temperature heat capacity measurements acquired with a physical property measurement system (PPMS) in the temperature range 5?Kproperties described above, the internally consistent thermodynamic database for the MgSO4·nH2O system was refined by a mathematical programming (MAP) analysis. As can be seen from the resulting phase diagrams, starkeyite is metastable in the entire T-%RH range. Due to kinetic limitations of kieserite formation, metastable occurrence of starkeyite might be possible under martian conditions. Key Words: Mg sulfates—Starkeyite—Thermodynamic data—Entropy—Enthalpy—Calorimetry. Astrobiology 12, 1042–1054. PMID:23095098

  15. Property Measurement

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Van is used by Land Inventory Systems to measure and map property for tax assessment purposes. It is adapted from navigation system of the Lunar Rover wheeled vehicle in which moon-exploring astronauts traveled as much as 20 miles from their Lunar Module base. Astronauts had to know their precise position so that in case of emergency they could take the shortest route back. Computerized navigational system kept a highly accurate record of the directional path providing continuous position report. Distance measuring subsystem was a more accurate counterpart of automobile odometer system counts revolutions of wheels and encoders generate electrical pulses for each fractional revolution and the computer analyzed the pulses to determine the distance traveled in a given direction.

  16. Structure and thermodynamic properties of liquid cesium at pressures below 10 GPa and temperatures below 4000 K according to the molecular dynamics data

    NASA Astrophysics Data System (ADS)

    Belashchenko, D. K.

    2015-11-01

    The models of cesium at temperatures of up to 4000 K, compressions of up to Y = V/ V 0 = 0.3, and pressures of up to 24 GPa were constructed by the molecular dynamics (MD) method using the EAM interparticle potential. The thermodynamic properties of the models are presented in the tables. The compressibility factors were calculated: Z = pV/ RT. The thermodynamic properties of the MD models were in satisfactory agreement with experiment in the range of parameters under study at a cesium density of higher than 1.2 g/cm3. The behavior of the models in the region of the van der Waals loop was analyzed. The calculated critical temperature of cesium T c was shown to be ~1950 ± 25 K, approximating the real temperature, the density was ~0.53 g/cm3, the pressure ~0.015 GPa, and the compressibility factor Z = pV/ RT ? 0.23. The states with a unity factor Z = 1 were observed at pressures below 0.20 GPa (at 2800 K); the temperature dependence of the density of the models with Z = 1 was almost linear, and the Boyle temperature T B was 7160 K; the ratio T c/ T B = 0.269 was very close to that for mercury (0.276). In the pressure and temperature ranges under study, the inversion of the Joule-Thomson coefficient was not observed, but took place at densities below 1.2 g/cm3. The structure of the liquid changed when the degree of compression of the cesium models changed from 0.54 to 0.52. This was reflected by a change in the degree of asymmetry of the first peak of the radial distribution function. An analysis of the structural data of the models of liquid sodium, potassium, and rubidium showed that the structure of these metals also experienced similar changes near the degree of compression 0.5; these changes in alkali metals are not related to the 6 s ? 5 d electron transition.

  17. Density functional theory study of the structural, electronic, lattice dynamical, and thermodynamic properties of Li4SiO4 and its capability for CO2 capture

    SciTech Connect

    Duan, Yuhua; Parlinski, K.

    2011-01-01

    The structural, electronic, lattice dynamical, optical, thermodynamic, and CO{sub 2} capture properties of monoclinic and triclinic phases of Li{sub 4}SiO{sub 4} are investigated by combining density functional theory with phonon lattice dynamics calculations. We found that these two phases have some similarities in their bulk and thermodynamic properties. The calculated bulk modulus and the cohesive energies of these two phases are close to each other. Although both of them are insulators, the monoclinic phase of Li{sub 4}SiO{sub 4} has a direct band gap of 5.24 eV while the triclinic Li{sub 4}SiO{sub 4} phase has an indirect band gap of 4.98 eV. In both phases of Li{sub 4}SiO{sub 4}, the s orbital of O mainly contributes to the lower-energy second valence band (VB{sub 2}) and the p orbitals contribute to the fist valence band (VB{sub 1}) and the conduction bands (CBs). The s orbital of Si mainly contributes to the lower portions of the VB1 and VB{sub 2}, and Si p orbitals mainly contribute to the higher portions of the VB{sub 1} and VB{sub 2}. The s and p orbitals of Li contribute to both VBs and to CBs, and Li p orbitals have a higher contribution than the Li s orbital. There is possibly a phonon soft mode existing in triclinic {gamma}-Li{sub 4}SiO{sub 4}; in the monoclinic Li{sub 4}SiO{sub 4}, there are three phonon soft modes, which correspond to the one type of Li disordered over a few sites. Their LO-TO splitting indicates that both phases of Li{sub 4}SiO{sub 4} are polar anisotropic materials. The calculated infrared absorption spectra for LO and TO modes are different for these two phases of Li{sub 4}SiO{sub 4}. The calculated relationships of the chemical potential versus temperature and CO{sub 2} pressure for reaction of Li{sub 4}SiO{sub 4} with CO{sub 2} shows that Li{sub 4}SiO{sub 4} could be a good candidate for a high-temperature CO{sub 2} sorbent while used for postcombustion capture technology.

  18. CO2 capture properties of lithium silicates with different ratios of Li2O/SiO2: an ab initio thermodynamic and experimental approach.

    PubMed

    Duan, Yuhua; Pfeiffer, Heriberto; Li, Bingyun; Romero-Ibarra, Issis C; Sorescu, Dan C; Luebke, David R; Halley, J Woods

    2013-08-28

    The lithium silicates have attracted scientific interest due to their potential use as high-temperature sorbents for CO2 capture. The electronic properties and thermodynamic stabilities of lithium silicates with different Li2O/SiO2 ratios (Li2O, Li8SiO6, Li4SiO4, Li6Si2O7, Li2SiO3, Li2Si2O5, Li2Si3O7, and ?-SiO2) have been investigated by combining first-principles density functional theory with lattice phonon dynamics. All these lithium silicates examined are insulators with band-gaps larger than 4.5 eV. By decreasing the Li2O/SiO2 ratio, the first valence bandwidth of the corresponding lithium silicate increases. Additionally, by decreasing the Li2O/SiO2 ratio, the vibrational frequencies of the corresponding lithium silicates shift to higher frequencies. Based on the calculated energetic information, their CO2 absorption capabilities were extensively analyzed through thermodynamic investigations on these absorption reactions. We found that by increasing the Li2O/SiO2 ratio when going from Li2Si3O7 to Li8SiO6, the corresponding lithium silicates have higher CO2 capture capacity, higher turnover temperatures and heats of reaction, and require higher energy inputs for regeneration. Based on our experimentally measured isotherms of the CO2 chemisorption by lithium silicates, we found that the CO2 capture reactions are two-stage processes: (1) a superficial reaction to form the external shell composed of Li2CO3 and a metal oxide or lithium silicate secondary phase and (2) lithium diffusion from bulk to the surface with a simultaneous diffusion of CO2 into the shell to continue the CO2 chemisorption process. The second stage is the rate determining step for the capture process. By changing the mixing ratio of Li2O and SiO2, we can obtain different lithium silicate solids which exhibit different thermodynamic behaviors. Based on our results, three mixing scenarios are discussed to provide general guidelines for designing new CO2 sorbents to fit practical needs. PMID:23824271

  19. CO2 capture properties of lithium silicates with different ratios of Li2O/SiO2: an ab initio thermodynamic and experimental approach

    SciTech Connect

    Duan, Y; Pfeiffer, H; Li, B; Romero-Iarra, I C; Sorescu, D C; Luebke, D; Halley, J W

    2013-07-26

    The lithium silicates have attracted scientific interest due to their potential use as high-temperature sorbents for CO2 capture. The electronic properties and thermodynamic stabilities of lithium silicates with different Li2O/SiO2 ratios (Li2O, Li8SiO6, Li4SiO4, Li6Si2O7, Li2SiO3, Li2Si2O5, Li2Si3O7, and a-SiO2) have been investigated by combining first-principles density functional theory with lattice phonon dynamics. All these lithium silicates examined are insulators with band-gaps larger than 4.5 eV. By decreasing the Li2O/SiO2 ratio, the first valence bandwidth of the corresponding lithium silicate increases. Additionally, by decreasing the Li2O/SiO2 ratio, the vibrational frequencies of the corresponding lithium silicates shift to higher frequencies. Based on the calculated energetic information, their CO2 absorption capabilities were extensively analyzed through thermodynamic investigations on these absorption reactions. We found that by increasing the Li2O/SiO2 ratio when going from Li2Si3O7 to Li8SiO6, the corresponding lithium silicates have higher CO2 capture capacity, higher turnover temperatures and heats of reaction, and require higher energy inputs for regeneration. Based on our experimentally measured isotherms of the CO2 chemisorption by lithium silicates, we found that the CO2 capture reactions are two-stage processes: (1) a superficial reaction to form the external shell composed of Li2CO3 and a metal oxide or lithium silicate secondary phase and (2) lithium diffusion from bulk to the surface with a simultaneous diffusion of CO2 into the shell to continue the CO2 chemisorption process. The second stage is the rate determining step for the capture process. By changing the mixing ratio of Li2O and SiO2, we can obtain different lithium silicate solids which exhibit different thermodynamic behaviors. Based on our results, three mixing scenarios are discussed to provide general guidelines for designing new CO2 sorbents to fit practical needs.

  20. Experimentally determined standard thermodynamic properties of synthetic MgSO(4)·4H(2)O (Starkeyite) and MgSO(4)·3H(2)O: a revised internally consistent thermodynamic data set for magnesium sulfate hydrates.

    PubMed

    Grevel, Klaus-Dieter; Majzlan, Juraj; Benisek, Artur; Dachs, Edgar; Steiger, Michael; Fortes, A Dominic; Marler, Bernd

    2012-11-01

    The enthalpies of formation of synthetic MgSO(4)·4H(2)O (starkeyite) and MgSO(4)·3H(2)O were obtained by solution calorimetry at T=298.15?K. The resulting enthalpies of formation from the elements are [Formula: see text] (starkeyite)=-2498.7±1.1?kJ·mol(-1) and [Formula: see text] (MgSO(4)·3H(2)O)=-2210.3±1.3?kJ·mol(-1). The standard entropy of starkeyite was derived from low-temperature heat capacity measurements acquired with a physical property measurement system (PPMS) in the temperature range 5?Kproperties described above, the internally consistent thermodynamic database for the MgSO(4)·nH(2)O system was refined by a mathematical programming (MAP) analysis. As can be seen from the resulting phase diagrams, starkeyite is metastable in the entire T-%RH range. Due to kinetic limitations of kieserite formation, metastable occurrence of starkeyite might be possible under martian conditions. PMID:23095098

  1. Thermodynamic properties distinguish human mitochondrial aspartyl-tRNA synthetase from bacterial homolog with same 3D architecture.

    PubMed

    Neuenfeldt, Anne; Lorber, Bernard; Ennifar, Eric; Gaudry, Agnès; Sauter, Claude; Sissler, Marie; Florentz, Catherine

    2013-02-01

    In the mammalian mitochondrial translation apparatus, the proteins and their partner RNAs are coded by two genomes. The proteins are nuclear-encoded and resemble their homologs, whereas the RNAs coming from the rapidly evolving mitochondrial genome have lost critical structural information. This raises the question of molecular adaptation of these proteins to their peculiar partner RNAs. The crystal structure of the homodimeric bacterial-type human mitochondrial aspartyl-tRNA synthetase (DRS) confirmed a 3D architecture close to that of Escherichia coli DRS. However, the mitochondrial enzyme distinguishes by an enlarged catalytic groove, a more electropositive surface potential and an alternate interaction network at the subunits interface. It also presented a thermal stability reduced by as much as 12°C. Isothermal titration calorimetry analyses revealed that the affinity of the mitochondrial enzyme for cognate and non-cognate tRNAs is one order of magnitude higher, but with different enthalpy and entropy contributions. They further indicated that both enzymes bind an adenylate analog by a cooperative allosteric mechanism with different thermodynamic contributions. The larger flexibility of the mitochondrial synthetase with respect to the bacterial enzyme, in combination with a preserved architecture, may represent an evolutionary process, allowing nuclear-encoded proteins to cooperate with degenerated organelle RNAs. PMID:23275545

  2. Thermodynamic mixing properties of the UO2-HfO2 solid solution: Density functional theory and Monte Carlo simulations

    NASA Astrophysics Data System (ADS)

    Yuan, Ke; Ewing, Rodney C.; Becker, Udo

    2015-03-01

    HfO2 is a neutron absorber and has been mechanically mixed with UO2 in nuclear fuel in order to control the core power distribution. During nuclear fission, the temperature at the center of the fuel pellet can reach above 1300 K, where hafnium may substitute uranium and form the binary solid solution of UO2-HfO2. UO2 adopts the cubic fluorite structure, but HfO2 can occur in monoclinic, tetragonal, and cubic structures. The distribution of Hf and U ions in the UO2-HfO2 binary and its atomic structure influence the thermal conductivity and melting point of the fuel. However, experimental data on the UO2-HfO2 binary are limited. Therefore, the enthalpies of mixing of the UO2-HfO2 binary with three different structures were calculated in this study using density functional theory and subsequent Monte Carlo simulations. The free energy of mixing was obtained from thermodynamic integration of the enthalpy of mixing over temperature. From the ?G of mixing, a phase diagram of the binary was obtained. The calculated UO2-HfO2 binary forms extensive solid solution across the entire compositional range, but there are a variety of possible exsolution phenomena associated with the different HfO2 polymorphs. As the structure of the HfO2 end member adopts lower symmetry and becomes less similar to cubic UO2, the miscibility gap of the phase diagram expands, accompanied by an increase in cell volume by 7-10% as the structure transforms from cubic to monoclinic. Close to the UO2 end member, which is relevant to the nuclear fuel, the isometric uranium-rich solid solutions exsolve as the fuel cools, and there is a tendency to form the monoclinic hafnium-rich phase in the matrix of the isometric, uranium-rich solid solution phase.

  3. Sign-Problem-Free Quantum Monte Carlo Study on Thermodynamic Properties and Magnetic Phase Transitions in Orbital-Active Itinerant Ferromagnets

    NASA Astrophysics Data System (ADS)

    Xu, Shenglong; Li, Yi; Wu, Congjun

    2015-04-01

    The microscopic mechanism of itinerant ferromagnetism is a long-standing problem due to the lack of nonperturbative methods to handle strong magnetic fluctuations of itinerant electrons. We nonpertubatively study thermodynamic properties and magnetic phase transitions of a two-dimensional multiorbital Hubbard model exhibiting ferromagnetic ground states. Quantum Monte Carlo simulations are employed, which are proved in a wide density region free of the sign problem usually suffered by simulations for fermions. Both Hund's coupling and electron itinerancy are essential for establishing the ferromagnetic coherence. No local magnetic moments exist in the system as a priori; nevertheless, the spin channel remains incoherent showing the Curie-Weiss-type spin magnetic susceptibility down to very low temperatures at which the charge channel is already coherent, exhibiting a weakly temperature-dependent compressibility. For the SU(2) invariant systems, the spin susceptibility further grows exponentially as approaching zero temperature in two dimensions. In the paramagnetic phase close to the Curie temperature, the momentum space Fermi distributions exhibit strong resemblance to those in the fully polarized state. The long-range ferromagnetic ordering appears when the symmetry is reduced to the Ising class, and the Curie temperature is accurately determined. These simulations provide helpful guidance to searching for novel ferromagnetic materials in both strongly correlated d -orbital transition-metal oxide layers and the p -orbital ultracold atom optical lattice systems.

  4. Spectroscopic investigation (FTIR spectrum), NBO, HOMO-LUMO energies, NLO and thermodynamic properties of 8-Methyl-N-vanillyl-6-nonenamideby DFT methods

    NASA Astrophysics Data System (ADS)

    Sherin Percy Prema Leela, J.; Hemamalini, R.; Muthu, S.; Al-Saadi, Abdulaziz A.

    2015-07-01

    Capsicum a hill grown vegetable is also known as red pepper or chili pepper. Capsaicin(8-Methyl-N-vanillyl-6-nonenamide) is the active component in chili peppers, which is currently used in the treatment of osteoarthritis, psoriasis and cancer. Fourier transform infrared (FT-IR) spectrum of Capsaicin in the solid phase were recorded in the region 4000-400 cm-1 and analyzed. The vibrational frequencies of the title compound were obtained theoretically by DFT/B3LYP calculations employing the standard 6-311++G(d,p) basis set and were compared with Fourier transform infrared spectrum. Complete vibrational assignment analysis and correlation of the fundamental modes for the title compound were carried out. The vibrational harmonic frequencies were scaled using scale factor, yielding a good agreement between the experimentally recorded and the theoretically calculated values. Stability of the molecule arising from hyper conjugative interactions, charge delocalization and intra molecular hydrogen bond-like weak interaction has been analyzed using Natural bond orbital (NBO) analysis by using B3LYP/6-311++G(d,p) method. The results show that electron density (ED) in the ?? and ?? antibonding orbitals and second-order delocalization energies E (2) confirm the occurrence of intra molecular charge transfer (ICT) within the molecule. The dipole moment (?), polarizability (?) and the hyperpolarizability (?) values of the molecule has been computed. Thermodynamic properties (heat capacity, entropy and enthalpy) of the title compound at different temperatures were calculated.

  5. Thermodynamics of arsenates, selenites, and sulfates in the oxidation zone of sulfide ores: V. Chalcomenite and its synthetic analog, properties, and formation conditions

    NASA Astrophysics Data System (ADS)

    Krivovichev, V. G.; Tarasevich, D. A.; Charykova, M. V.; Britvin, S. N.; Siidra, O. I.; Depmeier, W.

    2012-12-01

    Understanding the mechanisms of selenium behavior under near-surface conditions is a topical problem of modern mineralogy and geochemistry that is very important in solving some environmental problems. The objective of this study is to develop techniques of synthesizing a chalcomenite analog and to study its speciation and properties. The synthesis was performed by boiling-dry aqueous Cu2(CO3)(OH)2 solutions and selenium acid H2SeO3. The obtained samples were identified by X-ray diffraction and IR spectroscopy. The Eh-pH diagrams were calculated using the Geochemist's Workbench (GMB 7.0) software package. The database comprises the thermodynamic parameters of 46 elements, 47 main particles, 48 redox pairs, 551 particles in solution, 624 solid phases, and 10 gases. The Eh-pH diagrams have been calculated for the Cu-Se-CO2-H2O system for the average content of these elements in underground waters and their contents in acidic waters in the oxidation zones of sulfide deposits. The formation of chalcomenite and malachite under near-surface conditions is discussed.

  6. Spectroscopic investigation (FTIR spectrum), NBO, HOMO-LUMO energies, NLO and thermodynamic properties of 8-Methyl-N-vanillyl-6-nonenamideby DFT methods.

    PubMed

    Leela, J Sherin Percy Prema; Hemamalini, R; Muthu, S; Al-Saadi, Abdulaziz A

    2015-07-01

    Capsicum a hill grown vegetable is also known as red pepper or chili pepper. Capsaicin(8-Methyl-N-vanillyl-6-nonenamide) is the active component in chili peppers, which is currently used in the treatment of osteoarthritis, psoriasis and cancer. Fourier transform infrared (FT-IR) spectrum of Capsaicin in the solid phase were recorded in the region 4000-400 cm(-1) and analyzed. The vibrational frequencies of the title compound were obtained theoretically by DFT/B3LYP calculations employing the standard 6-311++G(d,p) basis set and were compared with Fourier transform infrared spectrum. Complete vibrational assignment analysis and correlation of the fundamental modes for the title compound were carried out. The vibrational harmonic frequencies were scaled using scale factor, yielding a good agreement between the experimentally recorded and the theoretically calculated values. Stability of the molecule arising from hyper conjugative interactions, charge delocalization and intra molecular hydrogen bond-like weak interaction has been analyzed using Natural bond orbital (NBO) analysis by using B3LYP/6-311++G(d,p) method. The results show that electron density (ED) in the ?? and ?? antibonding orbitals and second-order delocalization energies E (2) confirm the occurrence of intra molecular charge transfer (ICT) within the molecule. The dipole moment (?), polarizability (?) and the hyperpolarizability (?) values of the molecule has been computed. Thermodynamic properties (heat capacity, entropy and enthalpy) of the title compound at different temperatures were calculated. PMID:25813174

  7. Thermodynamic and magnetic properties of surface Fe3+ species on quartz: effects of gamma-ray irradiation and implications for aerosol-radiation interactions

    NASA Astrophysics Data System (ADS)

    SivaRamaiah, Gobburu; Pan, Yuanming

    2012-06-01

    Samples of a natural amethyst, pulverized in air, and irradiated for gamma-ray doses from 0.14 to 70 kGy, have been investigated by powder electron paramagnetic resonance (EPR) spectroscopy from 90 to 294 K. The powder EPR spectra show that the surface Fe3+ species on the gamma-ray-irradiated quartz differ from its counterpart without irradiation in both the effective g value and the observed line shape, suggesting marked radiation effects. This suggestion is supported by quantitatively determined thermodynamic properties, magnetic susceptibility, relaxation times, and geometrical radius. In particular, the surface Fe3+ species on gamma-ray-irradiated quartz has larger Gibbs and activation energies than its non-irradiated counterpart, suggesting radiation-induced chemical reactions. The shorter phase-memory time ( T m) but longer spin-lattice relaxation time ( T 1) of the surface Fe3+ species on the gamma-ray-irradiated quartz than that without irradiation indicate stronger dipolar interactions in the former. Moreover, the calculated geometrical radius of the surface Fe3+ species on the gamma-ray-irradiated quartz is three orders of magnitude larger than that of its counterpart on the as-is sample. These results provide new insights into radiation-induced aerosol nucleation, with relevance to atmospheric cloud formation and global climate changes.

  8. Thermodynamic and Kinetic Properties of Intrinsic Defects and Mg Transmutants in 3C-SiC Determined by Density Functional Theory

    SciTech Connect

    Hu, Shenyang Y.; Setyawan, Wahyu; Van Ginhoven, Renee M.; Jiang, Weilin; Henager, Charles H.; Kurtz, Richard J.

    2014-02-20

    Density functional theory (DFT) is used to calculate the thermodynamic and kinetic properties of transmutant Mg in 3C-SiC due to high-energy neutron irradiation associated with the fusion nuclear environment. The formation and binding energies of intrinsic defects, Mg-related defects, and clusters in 3C-SiC are systematically calculated. The minimum energy paths and activation energies during point defect migration and small cluster evolution are studied using a generalized solid-state elastic band (G-SSNEB) method with DFT energy calculations. Stable defect structures and possible defect migration mechanisms are identified. The evolution of binding energies during Mg2Si formation demonstrates that the formation of Mg2Si needs to overcome a critical nucleus size and nucleation barrier. It is also found that a compressive stress field exists around the Mg2Si nucleus. These data are important inputs in meso- and macro-scale modeling and experiments to understand and predict the impact of Mg on phase stability, microstructure evolution, and performance of SiC and SiC-based materials during long-term neutron exposures.

  9. Structure, processing, and properties of potatoes

    NASA Technical Reports Server (NTRS)

    Lloyd, Isabel K.; Kolos, Kimberly R.; Menegaux, Edmond C.; Luo, Huy; Mccuen, Richard H.; Regan, Thomas M.

    1992-01-01

    The objective of this experiment and lesson intended for high school students in an engineering or materials science course or college freshmen is to demonstrate the relation between processing, structure, and thermodynamic and physical properties. The specific objectives are to show the effect of structure and structural changes on thermodynamic properties (specific heat) and physical properties (compressive strength); to illustrate the first law of thermodynamics; to compare boiling a potato in water with cooking it in a microwave in terms of the rate of structural change and the energy consumed to 'process' the potato; and to demonstrate compression testing.

  10. Thermodynamic properties of chemical species in nuclear waste: Topical report: The solubilities of crystalline neodymium and americium trihydroxides

    SciTech Connect

    Silva, R.J.

    1982-12-01

    The solubilities of crystalline Nd(OH)/sub 3/ and Am(OH)/sub 3/ were measured at 25 +- 1/sup 0/C in aqueous solutions of 0.1 M NaClO/sub 4/ under argon as a function of pH by determination of the solution concentrations of Nd and Am. Prior to use in the solubility measurements, the solid materials were characterized through their x-ray powder patterns. Analyses of the solubility data with the computer code MINEQL allowed estimates of the solubility product constants, K/sub s10/, and the second and third hydrolysis constants, K/sub 12/ and K/sub 13/, for Nd/sup 3 +/ and Am/sup 3 +/. Upper limits for the fourth hydrolysis constants were also estimated. For Nd, they are: log K/sub s10/ = 16.0 +- .2, log K/sub 12/ = -15.8 +- .5, log K/sub 13/ = -23.9 +- .2 and log K/sub 14/ < -34. For Am, they are: log K/sub s10/ = 15.9 +- .4, log K/sub 12/ = -16.0 +- .7, log K/sub 13/ = -24.3 +- .3 and log K/sub 14/ < -34.5. The crystalline Nd(OH)/sub 3/ was found to be a factor of 100 to 300 less soluble than predicted from previously reported thermodynamic data over much of the pH range of environmental interest. The measured solubility of crystalline Am(OH)/sub 3/ was also considerably less than predicted from the previously estimated solubility product constant, i.e., a factor of about 600. For Am, the solubility of the crystalline material was a factor of about 30 less than the amorphous material. The solubilities of crystalline Nd(OH)/sub 3/ and Am(OH)/sub 3/ as a function of pH were found to be very similar and Nd(OH)/sub 3/ should be a good analog compound for Am(OH)/sub 3/.

  11. Estimation of Fluid Properties and Phase Equilibria.

    ERIC Educational Resources Information Center

    Herskowitz, M.

    1985-01-01

    Describes a course (given to junior/senior students with strong background in thermodynamics and transport phenomena) that covers the theoretical and practical aspects of properties estimation. An outline for the course is included. (JN)

  12. Structural, vibrational and thermodynamic properties of Mg2SiO4 and MgSiO3 minerals from first-principles simulations

    NASA Astrophysics Data System (ADS)

    Hernández, E. R.; Brodholt, J.; Alfè, D.

    2015-03-01

    In this paper we report a computational study of the structural and vibrational properties of the Mg-end members forsterite, wadsleyite and ringwoodite of Mg2SiO4 , and akimotoite, majorite and the perovskite phase of MgSiO3 . Our calculations have been carried out in the framework of Density Functional Theory (DFT) using a plane wave basis set and the Projector-augmented Wave (PAW) method to account for the core electrons. All structures have been fully relaxed at a series of volumes corresponding to the pressure range relevant to the transition zone in the Earth's mantle, and at each volume the phonon frequencies have been obtained and classified. Using the quasi-harmonic approximation, we have estimated a series of thermodynamic properties for each structure, including the Gibbs free energy, from which we have computed approximate phase diagrams for Mg2SiO4 and MgSiO3 . In spite of our reliance on the quasi-harmonic approximation, which is expected to break down at high temperatures, our calculated phase diagrams qualitatively reproduce the main features expected from diagrams fitted to experimental data. For example, from the computed phase diagram for Mg2SiO4 we obtain a post-spinel boundary at P = 22.1 GPa at T = 1873 K, with a slope of -3.4 MPa/K.This supports experimental results suggesting a relatively large slope rather than those favouring a much flatter one. It also suggests that vertical deflections of the 660 km discontinuity due to thermal signatures from plumes and slabs should be similar to those at the 410 km, and that a deflection of 35 km as seen in recent seismic studies could be caused by a thermal anomaly as small as 330 K. We also identify the triple point between the ringwoodite, ilmenite (plus periclase) and perovskite (plus periclase) phases to be at P = 22.9 GPa and T = 1565 K. Our results clearly illustrate the stringent requirements made on theoretical models in order to extract predictions compatible with the available experimental data.

  13. Thermodynamic properties of illite, smectite and beidellite by calorimetric methods: Enthalpies of formation, heat capacities, entropies and Gibbs free energies of formation

    NASA Astrophysics Data System (ADS)

    Gailhanou, H.; Blanc, P.; Rogez, J.; Mikaelian, G.; Kawaji, H.; Olives, J.; Amouric, M.; Denoyel, R.; Bourrelly, S.; Montouillout, V.; Vieillard, P.; Fialips, C. I.; Michau, N.; Gaucher, E. C.

    2012-07-01

    The thermodynamic properties of three aluminous 2:1 clay minerals were acquired at 1.013 bars and at temperatures between 5 and 500 K using various calorimetric methods. Calorimetric measurements were performed on hydrated and dehydrated <2 ?m clay fractions of smectite MX-80 (Wyoming), illite IMt-2 (Silver Hill) and beidellite SBId-1 (Black Jack Mine). After purification, the mineralogical analyses gave the following structural formulae: Na0.409K0.024Ca0.009 (Si3.738Al0.262) (Al1.598Mg0.214Fe 0.173 3 + Fe 0.035 2 +)O10(OH)2,K0.762Na0.044 (Si3.387Al0.613) (Al1.427Mg0.241Fe 0.292 3 + Fe 0.084 2 +)O10(OH)2 and Ca0.185K0.104 (Si3.574Al0.426) (Al1.812Mg0.09Fe 0.112 3 +)O10(OH)2 for smectite MX-80, illite IMt-2 and beidellite SBId-1, respectively. Heat capacities were measured by low temperature adiabatic calorimetry and differential scanning calorimetry, from 5 to 500 K. Standard enthalpies of formation were obtained from solution-reaction calorimetry at 298.15 K. The standard Gibbs free energies of formation of the clay minerals were also calculated, together with the equilibrium constants at 25 °C, for anhydrous and hydrated minerals. A comparison between these experimental data and estimated values obtained from prediction models available in the literature, enabled the calculation method that appears to be the most relevant to be selected, at least for aluminous 2:1 clay minerals.

  14. Determination of Thermal Properties of Composting Bulking Materials

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thermal properties of compost bulking materials affect temperature and biodegradation during the composting process. Well-determined thermal properties of compost feedstocks will therefore contribute to practical thermodynamic approaches. Thermal conductivity, thermal diffusivity, and volumetric hea...

  15. Determination of Thermal Properties of Composting Bulking Materials

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thermal properties of compost bulking materials affect temperature and biodegradation during the composting process. Well determined thermal properties of compost feedstocks will therefore contribute to practical thermodynamic approaches. Thermal conductivity, thermal diffusivity, and volumetric hea...

  16. Computing Properties Of Chemical Mixtures At Equilibrium

    NASA Technical Reports Server (NTRS)

    Mcbride, B. J.; Gordon, S.

    1995-01-01

    Scientists and engineers need data on chemical equilibrium compositions to calculate theoretical thermodynamic properties of chemical systems. Information essential in design and analysis of such equipment as compressors, turbines, nozzles, engines, shock tubes, heat exchangers, and chemical-processing equipment. CET93 is general program that calculates chemical equilibrium compositions and properties of mixtures for any chemical system for which thermodynamic data are available. Includes thermodynamic data for more than 1,300 gaseous and condensed species and thermal-transport data for 151 gases. Written in FORTRAN 77.

  17. Atomistic calculations of the thermodynamic properties of mixing for tetravalent metal dioxide solid solutions: (Zr, Th, Ce)O{sub 2}

    SciTech Connect

    Shuller-Nickles, L.C.; Ewing, R.C.; Becker, U.

    2013-01-15

    The thermodynamic mixing properties for isometric Th{sub x}Ce{sub 1-x}O{sub 2}, Ce{sub x}Zr{sub 1-x}O{sub 2}, and Th{sub x}Zr{sub 1-x}O{sub 2} were determined using quantum-mechanical calculations and subsequent Monte-Carlo simulations. Although the Th{sub x}Ce{sub 1-x}O{sub 2} binary indicates exsolution below 600 K, the energy gain due to exsolution is small (E{sub exsoln}=1.5 kJ/(mol cations) at 200 K). The energy gain for exsolution is significant for the binaries containing Zr; at 1000 K, E{sub exsoln}=6 kJ/(mol cations) for the Ce{sub x}Zr{sub 1-x}O{sub 2} binary, and E{sub exsoln}=17 kJ/(mol cations) for the Th{sub x}Zr{sub 1-x}O{sub 2} binary. The binaries containing Zr have limited miscibility and cation ordering (at 200 K for x=0.5). At 1673 K, only 4.0 and 0.25 mol% ZrO{sub 2} can be incorporated into CeO{sub 2} and ThO{sub 2}, respectively. Solid-solution calculations for the tetragonal Th{sub x}Zr{sub 1-x}O{sub 2} binary show decreased mixing enthalpy due to the increased end-member stability of tetragonal ZrO{sub 2}. Inclusion of the monoclinic ZrO{sub 2} is predicted to further reduce the mixing enthalpy for binaries containing Zr. - Graphical abstract: Temperature-composition phase diagram showing miscibility gaps for the isometric Th{sub x}Ce{sub 1-x}O{sub 2}, isometric Ce{sub x}Zr{sub 1-x}O{sub 2}, isometric Th{sub x}Zr{sub 1-x}O{sub 2}, and tetragonal Th{sub x}Zr{sub 1-x}O{sub 2} binaries at low composition (0thermodynamic stability of monoclinic and tetragonal ZrO{sub 2} end-member affects solid solution binaries.

  18. Structure-function properties of anticorrosive exopolyaccharides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nanoscale biobased exopolymer films were shown that provide protection to metal substrates under corrosive environments and that the films could be self-repairing in aqueous environments. This work describes the fundamental properties of thin exopolymer films including thermodynamic properties, film...

  19. Optical and thermodynamic properties of MgO from radiative shock temperature and sound speed measurements on samples preheated to 2300 K

    NASA Astrophysics Data System (ADS)

    Fatýanov, O. V.; Asimow, P. D.

    2013-12-01

    Thermodynamic properties of MgO, one of the major end-members of deep planetary interiors, play a significant role in the processes inside the Earth's lower mantle. Of particular importance in geophysics and geochemistry is the MgO melting behavior at high pressure. Despite considerable theoretical and experimental efforts over decades, it remains essentially unknown. The melting temperature predictions for MgO at 135 GPa, the Earth's core-mantle boundary pressure, range from 5 to 9 kK. In a continuous effort to resolve this inconsistency and to probe the P-T region previously unexplored, we developed a technique for radiative shock temperature measurements in single-crystal MgO preheated to 2300 K. Large ventilated Mo capsules were employed to hold ~20 mm long MgO crystals with controlled longitudinal thermal gradients. These hot targets were impacted by 0.8 mm thick Ta flyers launched at 6.5 to 7.5 km/s on the Caltech two-stage light-gas gun. Six spectral radiance histories from MgO shock front were recorded in every shot with 3 ns time resolution over 440-750 nm or 500-830 nm spectral range. The majority of our experiments showed smooth pressure dependence of MgO shock temperature and sound speed consistent with the solid phase at 197-243 GPa. Although most observed temperatures are ~700 K lower and sound speeds ~1 km/s higher than the model predictions, the pressure slopes for both parameters are in close agreement with those calculated for the solid phase. Unconfirmed data from a single experiment at 239 GPa and 8.3 kK showed correlated temperature and sound speed anomalies (both values lower than expected) that may be explained by partial melting. Our past and recent data on shock-compressed preheated MgO suggest its melting curve above 200 GPa is higher than the extrapolation of the experiments of Zerr & Boehler or the theoretical calculation by Strachan et. al. These results, features of shock experiments with 2300 K pre-heat temperatures, data analysis, and future plans will be discussed.

  20. Ab initio studies on phase transition, thermoelastic, superconducting and thermodynamic properties of the compressed cubic phase of AlH{sub 3}

    SciTech Connect

    Wei, Yong-Kai; Ge, Ni-Na; Chen, Xiang-Rong E-mail: cyfjkf@caep.ac.cn; Ji, Guang-Fu E-mail: cyfjkf@caep.ac.cn; Cai, Ling-Cang; Gu, Zhuo-Wei

    2014-03-28

    The phase transition, thermoelastic, lattice dynamic, and thermodynamic properties of the cubic metallic phase AlH{sub 3} were obtained within the density-function perturbation theory. The calculated elastic modulus and phonon dispersion curves under various pressures at 0?K indicate the cubic phase is both mechanically and dynamically stable above 73 GPa. The superconducting transition temperature T{sub c} was calculated using the Allen-Dynes modification of the McMillan formula based on BCS theory. The calculations show that T{sub c} for the cubic phase AlH{sub 3} is 8.5?K (?{sup *}=0.1) at the onset of this phase (73?GPa), while decreases to 5.7?K at 80?GPa and almost disappears at 110?GPa, consisting with experimental phenomenon that there was no superconducting transition observed down to 4?K over a wide pressure range 110–164?GPa. It is found that the soft phonon mode for branch 1, namely, the lowest acoustic mode, plays a crucial role in elevating the total EPC parameter ? of cubic AlH{sub 3}. And the evolution of T{sub c} with pressure follows the corresponding change of this soft mode, i.e. this mode is responsible for the disappearance of T{sub c} in experiments. Meanwhile, the softening of this lowest acoustic mode originates from the electronic momentum transfer from M to R point. This phenomenon provides an important insight into why drastic changes in the diffraction pattern were observed in the pressure range of 63–73?GPa in Goncharenko's experiments. Specifically, once finite electronic temperature effects are included, we find that dynamical instabilities can be removed in the phonon dispersion for P?63?GPa, rendering the metastability of this phase in the range of 63–73?GPa, and T{sub c} (15.4?K) becomes remarkably high under the lowest possible pressure (63?GPa) compared with that of under 73?GPa (8.5?K). Our calculations open the possibility that finite temperature may allow cubic AlH{sub 3} to be dynamically stabilized even for pressures below 73 GPa. It is reasonable to deduced that if special techniques, such as rapid decompression, quenching, and annealing, are implemented in experiments, higher T{sub c} can be observed in hydrides or hydrogen-rich compounds under much lower pressure than ever before.