Thermodynamical properties and thermoelastic coupling of complex macroscopic structure
International Nuclear Information System (INIS)
Fabbri, M.; Sacripanti, A.
1996-11-01
Gross qualitative/quantitative analysis about thermodynamical properties and thermoelastic coupling (or elastocaloric effect) of complex macroscopic structure (running shoes) is performed by infrared camera. The experimental results showed the achievability of a n industrial research project
Statistical thermodynamics understanding the properties of macroscopic systems
Fai, Lukong Cornelius
2012-01-01
Basic Principles of Statistical PhysicsMicroscopic and Macroscopic Description of StatesBasic PostulatesGibbs Ergodic AssumptionGibbsian EnsemblesExperimental Basis of Statistical MechanicsDefinition of Expectation ValuesErgodic Principle and Expectation ValuesProperties of Distribution FunctionRelative Fluctuation of an Additive Macroscopic ParameterLiouville TheoremGibbs Microcanonical EnsembleMicrocanonical Distribution in Quantum MechanicsDensity MatrixDensity Matrix in Energy RepresentationEntropyThermodynamic FunctionsTemperatureAdiabatic ProcessesPressureThermodynamic IdentityLaws of Th
Thermodynamic properties of minerals: Macroscopic and microscopic approaches
International Nuclear Information System (INIS)
Richet, P.; Gillet, P.; Fiquet, G.
1992-01-01
Thermodynamic modeling of experimental or natural-phase equilibria has become an integral part of petrology. In this respect, the isobaric heat capacity (C p ) has manifold importance. First, C p data constitute the basis of third-law determinations of the entropy of minerals. Second, these data are needed to calculate the variation with temperature of the entropy, the entropy, and the Gibbs free energy. As a result, it necessary to know accurately heat capacities when retrieving thermodynamic information from phase equilibria data, especially when trying to separate the effects of the enthalpies and entropies of transformation. In this paper, we broadly review the main empiricial and theoretical aspects of the heat capacity of minerals. We begin with a brief review of the three main techniques that are currently in use for determining heat capacities from 0 to 2000 K, namely, adiabatic, differential scanning (DSC), and drop colarimetry, paying attention to the experimental constraints that limit measurements to certain conditions. When minerals can be subjected at best to limited calorimetric measurements, either because of lack of gram-sized samples or of instability at high temperatures (as if often the case with high-pressure minerals), other ways have to be found for predicting standard entropies and high-temperature properties. The validity of empiricial methods of prediction of the heat capacity as a function of temperature and composition will thus be discussed
Stochastic and Macroscopic Thermodynamics of Strongly Coupled Systems
Directory of Open Access Journals (Sweden)
Christopher Jarzynski
2017-01-01
Full Text Available We develop a thermodynamic framework that describes a classical system of interest S that is strongly coupled to its thermal environment E. Within this framework, seven key thermodynamic quantities—internal energy, entropy, volume, enthalpy, Gibbs free energy, heat, and work—are defined microscopically. These quantities obey thermodynamic relations including both the first and second law, and they satisfy nonequilibrium fluctuation theorems. We additionally impose a macroscopic consistency condition: When S is large, the quantities defined within our framework scale up to their macroscopic counterparts. By satisfying this condition, we demonstrate that a unifying framework can be developed, which encompasses both stochastic thermodynamics at one end, and macroscopic thermodynamics at the other. A central element in our approach is a thermodynamic definition of the volume of the system of interest, which converges to the usual geometric definition when S is large. We also sketch an alternative framework that satisfies the same consistency conditions. The dynamics of the system and environment are modeled using Hamilton’s equations in the full phase space.
Macroscopic Theory for Evolving Biological Systems Akin to Thermodynamics.
Kaneko, Kunihiko; Furusawa, Chikara
2018-05-20
We present a macroscopic theory to characterize the plasticity, robustness, and evolvability of biological responses and their fluctuations. First, linear approximation in intracellular reaction dynamics is used to demonstrate proportional changes in the expression of all cellular components in response to a given environmental stress, with the proportion coefficient determined by the change in growth rate as a consequence of the steady growth of cells. We further demonstrate that this relationship is supported through adaptation experiments of bacteria, perhaps too well as this proportionality is held even across cultures of different types of conditions. On the basis of simulations of cell models, we further show that this global proportionality is a consequence of evolution in which expression changes in response to environmental or genetic perturbations are constrained along a unique one-dimensional curve, which is a result of evolutionary robustness. It then follows that the expression changes induced by environmental changes are proportionally reduced across different components of a cell by evolution, which is akin to the Le Chatelier thermodynamics principle. Finally, with the aid of a fluctuation-response relationship, this proportionality is shown to hold between fluctuations caused by genetic changes and those caused by noise. Overall, these results and support from the theoretical and experimental literature suggest a formulation of cellular systems akin to thermodynamics, in which a macroscopic potential is given by the growth rate (or fitness) represented as a function of environmental and evolutionary changes.
Leinonen, Risto; Asikainen, Mervi A.; Hirvonen, Pekka E.
2015-01-01
This study concentrates on evaluating the consistency of upper-division students' use of the second law of thermodynamics at macroscopic and microscopic levels. Data were collected by means of a paper and pencil test (N = 48) focusing on the macroscopic and microscopic features of the second law concerned with heat transfer processes. The data…
The N-salicylidene aniline mesogen: Microscopic and macroscopic properties
International Nuclear Information System (INIS)
Nesrullazade, A.
2004-01-01
The vast majority of compounds exhibiting Iiquid crystalline phases may be regarded as having a rigid molecular central group with one or two flexible terminal alkyl or alkyloxy chains. The N-saIicyIidene anilines are very interesting and important materials both from fundamental and application points of view. These materials are on the one hand the ligands used to obtain metal containing complexes and on the other hand they are materials having the thermotropic mesomorphism. In this work we present investigations of microscopic and macroscopic properties of the 4-(Octyloxy)-N-(4-hexylphenyl)-2-hydrobenzaIimine (8SA) compound which was synthesized by our group. The 8SA compound shows the smectic C and nematic mesophases. These mesophases are enantiotropic and display specific confocal and schlieren textures, respectively. Thermotropic and thermodynamical properties of the straight and reverse phase transitions between smectic C and nematic mesophases and between nematic mesophase and isotropic liquid have been investigated
Systematic vibration thermodynamic properties of bromine
Liu, G. Y.; Sun, W. G.; Liao, B. T.
2015-11-01
Based on the analysis of the maturity and finiteness of vibrational levels of bromine molecule in ground state and evaluating the effect on statistical computation, according to the elementary principles of quantum statistical theorem, using the full set of bromine molecular vibrational levels determined with algebra method, the statistical contribution for bromine systematical macroscopic thermodynamic properties is discussed. Thermodynamic state functions Helmholtz free energy, entropy and observable vibration heat capacity are calculated. The results show that the determination of full set of vibrational levels and maximum vibrational quantum number is the key in the correct statistical analysis of bromine systematical thermodynamic property. Algebra method results are clearly different from data of simple harmonic oscillator and the related algebra method results are no longer analytical but numerical and are superior to simple harmonic oscillator results. Compared with simple harmonic oscillator's heat capacities, the algebra method's heat capacities are more consistent with the experimental data in the given temperature range of 600-2100 K.
Thermodynamic properties of vanadium
International Nuclear Information System (INIS)
Desai, P.D.
1986-01-01
This work reviews and discusses the data and information on the various thermodynamic properties of vanadium available through March 1985. These include the heat capacity and enthalpy, enthalpy of melting, vapor pressure, and enthalpy of vaporization. The existing data have been critically evaluated and analyzed, and the recommended values for heat capacity, enthalpy, entropy, and Gibbs energy function covering the temperature range from 1 to 3800 K have been generated. These values are referred to tempertures based on IPTS-1968. The units used for various properties are joules per mole (J. mol - 1 ). The estimated uncertainties in the heat capacity are +/-3% below 15 K, +/-10% from 15 to 150 K, +/-3% from 150 to 298.15 K, +/-2% from 298.15 to 1000 K, +/-3% from 1000 to the melting point (2202 K), and +/-5% in the liquid region
Thermodynamic properties of cryogenic fluids
Leachman, Jacob; Lemmon, Eric; Penoncello, Steven
2017-01-01
This update to a classic reference text provides practising engineers and scientists with accurate thermophysical property data for cryogenic fluids. The equations for fifteen important cryogenic fluids are presented in a basic format, accompanied by pressure-enthalpy and temperature-entropy charts and tables of thermodynamic properties. It begins with a chapter introducing the thermodynamic relations and functional forms for equations of state, and goes on to describe the requirements for thermodynamic property formulations, needed for the complete definition of the thermodynamic properties of a fluid. The core of the book comprises extensive data tables and charts for the most commonly-encountered cryogenic fluids. This new edition sees significant updates to the data presented for air, argon, carbon monoxide, deuterium, ethane, helium, hydrogen, krypton, nitrogen and xenon. The book supports and complements NIST’s REFPROP - an interactive database and tool for the calculation of thermodynamic propertie...
Directory of Open Access Journals (Sweden)
Risto Leinonen
2015-09-01
Full Text Available [This paper is part of the Focused Collection on Upper Division Physics Courses.] This study concentrates on evaluating the consistency of upper-division students’ use of the second law of thermodynamics at macroscopic and microscopic levels. Data were collected by means of a paper and pencil test (N=48 focusing on the macroscopic and microscopic features of the second law concerned with heat transfer processes. The data analysis was based on a qualitative content analysis where students’ responses to the macroscopic- and microscopic-level items were categorized to provide insight into the consistency of the students’ ideas; if students relied on the same idea at both levels, they ended up in the same category at both levels, and their use of the second law was consistent. The most essential finding is that a majority of students, 52%–69% depending on the physical system under evaluation, used the second law of thermodynamics consistently at macroscopic and microscopic levels; approximately 40% of the students used it correctly in terms of physics while others relied on erroneous ideas, such as the idea of conserving entropy. The most common inconsistency harbored by 10%–15% of the students (depending on the physical system under evaluation was students’ tendency to consider the number of accessible microstates to remain constant even if the entropy was stated to increase in a similar process; other inconsistencies were only seen in the answers of a few students. In order to address the observed inconsistencies, we would suggest that lecturers should utilize tasks that challenge students to evaluate phenomena at macroscopic and microscopic levels concurrently and tasks that would guide students in their search for contradictions in their thinking.
Macroscopic plasma properties and stability theory
International Nuclear Information System (INIS)
Sakanaka, P.H.
1981-01-01
1. Two-fluid equations: (a) Boltzmann equation: complete set of equations; collision models - Vlasov, BGK, Fokker-Planck-Landau, Boltzmann. (b) Moments of the Boltzmann equation: problem of closure. (c) Two-fluid equations. 2. One-fluid equation: (a) One-fluid variables. (b) One-fluid equations: quasi-neutrality. (c) Resistive MHD equations. (d) Ideal MHD equations: one-adiabatic approximation; double-adiabatic approximation - CGL. 3. MHD stability problem - energy principle: (a) Linearized ideal MHD equations: force-operator equation. (b) Boundary conditions. (c) Self-adjointness of force operator. (d) The energy principle. 4. Stability problems: application of the energy principle; stability of sharp-boundary plasmas. 5. Thermodynamic approach for stability of plasmas: Newcomb and Rosenbluth's stability criteria. (author)
Macroscopic properties of model disordered materials
International Nuclear Information System (INIS)
Knackstedt, M.A.; Roberts, A.P.
1996-01-01
Disordered materials are ubiquitous in nature and in industry. Soils, sedimentary rocks, wood, bone, polymer composites, foams, catalysts, gels, concretes and ceramics have properties that depend on material structure. Present techniques for predicting properties are limited by the theoretical and computational difficulty of incorporating a realistic description of material structure. A general model for microstructure was recently proposed by Berk [Berk, Phys.Rev.A, 44 5069 (1991)]. The model is based on level cuts of a Gaussian random field with arbitrary spectral density. The freedom in specifying the parameters of the model allows the modeling of physical materials with diverse morphological characteristics. We have shown that the model qualitatively accounts for the principal features of a wider variety of disordered materials including geologic media, membranes, polymer blends, ceramics and foams. Correlation functions are derived for the model microstructure. From this characterisation we derive mechanical and conductive properties of the materials. Excellent agreement with experimentally measured properties of disordered solids is obtained. The agreement provides a strong hint that it is now possible to correlate effective physical properties of porous solids to microstructure. Simple extensions to modelling properties of non-porous multicomponent blends; metal alloys, ceramics, metal/matrix and polymer composites are also discussed
Thermodynamical properties of dark energy
International Nuclear Information System (INIS)
Gong Yungui; Wang Bin; Wang Anzhong
2007-01-01
We have investigated the thermodynamical properties of dark energy. Assuming that the dark energy temperature T∼a -n and considering that the volume of the Universe enveloped by the apparent horizon relates to the temperature, we have derived the dark energy entropy. For dark energy with constant equation of state w>-1 and the generalized Chaplygin gas, the derived entropy can be positive and satisfy the entropy bound. The total entropy, including those of dark energy, the thermal radiation, and the apparent horizon, satisfies the generalized second law of thermodynamics. However, for the phantom with constant equation of state, the positivity of entropy, the entropy bound, and the generalized second law cannot be satisfied simultaneously
Thermodynamic properties of sea air
Directory of Open Access Journals (Sweden)
R. Feistel
2010-02-01
Full Text Available Very accurate thermodynamic potential functions are available for fluid water, ice, seawater and humid air covering wide ranges of temperature and pressure conditions. They permit the consistent computation of all equilibrium properties as, for example, required for coupled atmosphere-ocean models or the analysis of observational or experimental data. With the exception of humid air, these potential functions are already formulated as international standards released by the International Association for the Properties of Water and Steam (IAPWS, and have been adopted in 2009 for oceanography by IOC/UNESCO.
In this paper, we derive a collection of formulas for important quantities expressed in terms of the thermodynamic potentials, valid for typical phase transitions and composite systems of humid air and water/ice/seawater. Particular attention is given to equilibria between seawater and humid air, referred to as "sea air" here. In a related initiative, these formulas will soon be implemented in a source-code library for easy practical use. The library is primarily aimed at oceanographic applications but will be relevant to air-sea interaction and meteorology as well.
The formulas provided are valid for any consistent set of suitable thermodynamic potential functions. Here we adopt potential functions from previous publications in which they are constructed from theoretical laws and empirical data; they are briefly summarized in the appendix. The formulas make use of the full accuracy of these thermodynamic potentials, without additional approximations or empirical coefficients. They are expressed in the temperature scale ITS-90 and the 2008 Reference-Composition Salinity Scale.
International Nuclear Information System (INIS)
Dubacq, B.
2008-12-01
Phyllosilicates are important minerals in metamorphic petrology as well as in waste storage sites where clays are extensively used. Despite this fact, there is no thermodynamic model allowing to describe and to predict properly the behaviour of clay minerals (for example variation of volume with dehydration) and their phase relations with other minerals in metamorphic conditions. Inversely, the thermodynamic models of phengites are well constrained at high pressure and temperature but do not allow accurate thermo-barometric estimations at temperatures less than about 350 C. In this study, we propose two new thermodynamic models for smectites, illites, mixed-layers illites / smectites and phengites. With these models, it is possible to predict the composition of stable clays at low temperature and to estimate the pressure and temperature of crystallisation of di-octahedral aluminous phyllosilicates. These models take into consideration the hydration state of clay minerals as a function of pressure, temperature and water activity. The thermodynamic properties of solid solutions and hydrated mica-like end-members have been estimated in order to reproduce experimental results of i) clay dehydration, ii) nature of stable phases, iii) calorimetric measurements, as well as known (or estimated with independent methods) pressure-temperature conditions of crystallization of phyllosilicates analyses, from diagenesis conditions to ultra - high - pressure / temperature conditions. Phase diagrams have been computed with these models in simple systems. Conditions of crystallization of phyllosilicates have been estimated on many samples, including electron microprobe compositional maps. We investigated several approaches to estimate thermodynamic properties of minerals. All these methods revealed to be insufficiently accurate to estimate standard enthalpy of formation; calculated enthalpies of formation can not be directly used for thermo-barometric estimations. However, we
Thermodynamic properties of uranium--mercury system
International Nuclear Information System (INIS)
Lee, T.S.
1979-01-01
The EMF values in the fused salt cells of the type U(α)/KCl--LiCl--BaCl 2 eutectic, UCl 3 /U--Hg alloy, for the different two-phase alloys in the uranium--mercury system have been measured and the thermodynamic properties of this system have been calculated. These calculated values are in good agreement with values based on mercury vapor pressure measurements made by previous investigators. The inconsistency of the thermodynamic properties with the phase diagram determined by Frost are also confirmed. A tentative phase diagram based on the thermodynamic properties measured in this work was constructed
Thermodynamic Property Needs for the Oleochemical Industry
DEFF Research Database (Denmark)
Ana Perederic, Olivia; Kalakul, Sawitree; Sarup, Bent
The oleochemical industry cover mainly the food and pharmaceutical reactions but production offuels (biodiesel) and other speciality chemical production processes also handle oleochemicals (inother words, lipids). The core of process synthesis and design depend on availability of properties data...... and/or reliable thermodynamic models for the chemicals involved. Limited availability ofconsistent physical and thermodynamic properties of lipids compounds and their mixtures lead to difficulties with the use of process simulators for process synthesis and design, since all themodels to be used...
Tables of thermodynamic properties of sodium
International Nuclear Information System (INIS)
Fink, J.K.
1982-06-01
The thermodynamic properties of saturated sodium, superheated sodium, and subcooled sodium are tabulated as a function of temperature. The temperature ranges are 380 to 2508 K for saturated sodium, 500 to 2500 K for subcooled sodium, and 400 to 1600 K for superheated sodium. Tabulated thermodynamic properties are enthalpy, heat capacity, pressure, entropy, density, instantaneous thermal expansion coefficient, compressibility, and thermal pressure coefficient. Tables are given in SI units and cgs units
Nanofluidics thermodynamic and transport properties
Michaelides, Efstathios E (Stathis)
2014-01-01
This volume offers a comprehensive examination of the subject of heat and mass transfer with nanofluids as well as a critical review of the past and recent research projects in this area. Emphasis is placed on the fundamentals of the transport processes using particle-fluid suspensions, such as nanofluids. The nanofluid research is examined and presented in a holistic way using a great deal of our experience with the subjects of continuum mechanics, statistical thermodynamics, and non-equilibrium thermodynamics of transport processes. Using a thorough database, the experimental, analytical, and numerical advances of recent research in nanofluids are critically examined and connected to past research with medium and fine particles as well as to functional engineering systems. Promising applications and technological issues of heat/mass transfer system design with nanofluids are also discussed. This book also: Provides a deep scientific analysis of nanofluids using classical thermodynamics and statistical therm...
Thermodynamics and statistical mechanics. [thermodynamic properties of gases
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.
Microstructure and macroscopic properties of polydisperse systems of hard spheres
Ogarko, V.
2014-01-01
This dissertation describes an investigation of systems of polydisperse smooth hard spheres. This includes the development of a fast contact detection algorithm for computer modelling, the development of macroscopic constitutive laws that are based on microscopic features such as the moments of the
Thermodynamic properties of potassium chloride aqueous solutions
Zezin, Denis; Driesner, Thomas
2017-04-01
Potassium chloride is a ubiquitous salt in natural fluids, being the second most abundant dissolved salt in many geological aqueous solutions after sodium chloride. It is a simple solute and strong electrolyte easily dissociating in water, however the thermodynamic properties of KCl aqueous solutions were never correlated with sufficient accuracy for a wide range of physicochemical conditions. In this communication we propose a set of parameters for a Pitzer-type model which allows calculation of all necessary thermodynamic properties of KCl solution, namely excess Gibbs free energy and derived activity coefficient, apparent molar enthalpy, heat capacity and volume, as well as osmotic coefficient and activity of water in solutions. The system KCl-water is one of the best studied aqueous systems containing electrolytes. Although extensive experimental data were collected for thermodynamic properties of these solutions over the years, the accurate volumetric data became available only recently, thus making possible a complete thermodynamic formulation including a pressure dependence of excess Gibbs free energy and derived properties of the KCl-water liquids. Our proposed model is intended for calculation of major thermodynamic properties of KCl aqueous solutions at temperatures ranging from freezing point of a solution to 623 K, pressures ranging from saturated water vapor up to 150 MPa, and concentrations up to the salt saturation. This parameterized model will be further implemented in geochemical software packages and can facilitate the calculation of aqueous equilibrium for reactive transport codes.
Thermodynamic and transport properties of gaseous tetrafluoromethane in chemical equilibrium
Hunt, J. L.; Boney, L. R.
1973-01-01
Equations and in computer code are presented for the thermodynamic and transport properties of gaseous, undissociated tetrafluoromethane (CF4) in chemical equilibrium. The computer code calculates the thermodynamic and transport properties of CF4 when given any two of five thermodynamic variables (entropy, temperature, volume, pressure, and enthalpy). Equilibrium thermodynamic and transport property data are tabulated and pressure-enthalpy diagrams are presented.
An introduction to equilibrium thermodynamics
Morrill, Bernard; Hartnett, James P; Hughes, William F
1973-01-01
An Introduction to Equilibrium Thermodynamics discusses classical thermodynamics and irreversible thermodynamics. It introduces the laws of thermodynamics and the connection between statistical concepts and observable macroscopic properties of a thermodynamic system. Chapter 1 discusses the first law of thermodynamics while Chapters 2 through 4 deal with statistical concepts. The succeeding chapters describe the link between entropy and the reversible heat process concept of entropy; the second law of thermodynamics; Legendre transformations and Jacobian algebra. Finally, Chapter 10 provides a
Thermodynamic properties of water solvating biomolecular surfaces
Heyden, Matthias
Changes in the potential energy and entropy of water molecules hydrating biomolecular interfaces play a significant role for biomolecular solubility and association. Free energy perturbation and thermodynamic integration methods allow calculations of free energy differences between two states from simulations. However, these methods are computationally demanding and do not provide insights into individual thermodynamic contributions, i.e. changes in the solvent energy or entropy. Here, we employ methods to spatially resolve distributions of hydration water thermodynamic properties in the vicinity of biomolecular surfaces. This allows direct insights into thermodynamic signatures of the hydration of hydrophobic and hydrophilic solvent accessible sites of proteins and small molecules and comparisons to ideal model surfaces. We correlate dynamic properties of hydration water molecules, i.e. translational and rotational mobility, to their thermodynamics. The latter can be used as a guide to extract thermodynamic information from experimental measurements of site-resolved water dynamics. Further, we study energy-entropy compensations of water at different hydration sites of biomolecular surfaces. This work is supported by the Cluster of Excellence RESOLV (EXC 1069) funded by the Deutsche Forschungsgemeinschaft.
Relationship Between Filler-Matrix Interface and Macroscopical Properties of Polymer Nanocomposites
Ventura, Isaac Aguilar
2017-01-01
The macroscopic properties of Multiwall Carbon Nanotube (MWCNT) polymer nano-composites and multiscale composites have been studied from a multifunctional standpoint. The objective is to understand and correlate the mechanisms in which the addition
Organogels thermodynamics, structure, solvent role, and properties
Guenet, Jean-Michel
2016-01-01
This book provides a physics-oriented introduction to organogels with a comparison to polymer thermoreversible gels whenever relevant. The past decade has seen the development of a wide variety of newly-synthesized molecules that can spontaneously self-assemble or crystallize from their organic or aqueous solutions to produce fibrillar networks, namely organogels, with potential applications in organic electronics, light harvesting, bio-imaging, non-linear optics, and the like. This compact volume presents a detailed outlook of these novel molecular systems with special emphasis upon their thermodynamics, morphology, molecular structure, and rheology. The definition of these complex systems is also tackled, as well as the role of the solvent. The text features numerous temperature-phase diagrams for a variety of organogels as well as illustrations of their structures at the microscopic, mesoscopic and macroscopic level. A review of some potential applications is provided including hybrid functional materials ...
Thermodynamic properties of trizirconium tetraphosphate
International Nuclear Information System (INIS)
Pet'kov, V.I.; Asabina, E.A.; Kir'yanov, K.V.; Markin, A.V.; Smirnova, N.N.; Kitaev, D.B.; Kovalsky, A.M.
2005-01-01
The heat capacity measurements of the crystalline trizirconium tetraphosphate were carried out in a low-temperature adiabatic vacuum calorimeter between T=(7 and 350) K and in dynamic calorimeter between T=(330 and 640) K. The experimental data were used to calculate the standard (p 0 =0.1 MPa) thermodynamic functions Cp,m-bar /R,Δ0THm-bar /RT,Δ0TSm-bar /R,andΦm-bar =Δ0TSm-bar -Δ0THm-bar /T (where R is the universal gas constant) in the range T->(0 to 640) K. The fractal dimension D fr for the crystalline phosphate Zr 3 (PO 4 ) 4 between T=(20 and 40) K was evaluated. From hydrofluoric acid solution microcalorimetry, the enthalpy of solution of Zr 3 (PO 4 ) 4 at T=298.15 K was determined and the standard molar enthalpy of formation was derived. By combining the data obtained by the two techniques, the standard molar Gibbs function of formation of Zr 3 (PO 4 ) 4 at T=298.15 K was calculated
Thermodynamic properties of organic compounds estimation methods, principles and practice
Janz, George J
1967-01-01
Thermodynamic Properties of Organic Compounds: Estimation Methods, Principles and Practice, Revised Edition focuses on the progression of practical methods in computing the thermodynamic characteristics of organic compounds. Divided into two parts with eight chapters, the book concentrates first on the methods of estimation. Topics presented are statistical and combined thermodynamic functions; free energy change and equilibrium conversions; and estimation of thermodynamic properties. The next discussions focus on the thermodynamic properties of simple polyatomic systems by statistical the
Thermodynamic properties of aqueous hydroxyurea solutions
International Nuclear Information System (INIS)
Kumar, Shekhar; Sinha, Pranay Kumar; Kamachi Mudali, U.; Natarajan, R.
2011-01-01
Hydroxyurea is a novel reductant for uranium-plutonium separation in PUREX process. Little information on its thermophysical properties is available in published literature. In this work, its contributions to aqueous density, apparent molal volume, vapour pressure and thermodynamic water activity values, derived from in-house experiments, are reported. (author)
Thermodynamic properties of gaseous propane from model ...
African Journals Online (AJOL)
A fourth-order virial equation of state was combined with isotropic model potentials to predict accurate volumetric and caloric thermodynamic properties of propane in the gas phase. The parameters in the model were determined in a fit to speed-of-sound data alone; no other data were used. The approximation employed for ...
Thermodynamical Properties of 56Fe
International Nuclear Information System (INIS)
Tavukcu, E.; Becker, J.A.; Bernstein, L.A.; Garrett, P.E.; Guttormsen, M.; Mitchell, G.E.; Rekstad, J.; Schiller, A.; Siem, S.; Voinov, A.; Younes, W.
2002-01-01
Average nuclear level densities close to the nuclear binding energy in 56 Fe and 57 Fe are extracted from primary γ-ray spectra. Thermal properties of 56 Fe are studied within the statistical canonical ensemble. The experimental heat capacity is compared with the theoretical heat capacity calculated within the shell model Monte Carlo approach
Thermodynamic properties of α-uranium
International Nuclear Information System (INIS)
Ren, Zhiyong; Wu, Jun; Ma, Rong; Hu, Guichao; Luo, Chao
2016-01-01
The lattice constants and equilibrium atomic volume of α-uranium were calculated by Density Functional Theory (DFT). The first principles calculation results of the lattice for α-uranium are in agreement with the experimental results well. The thermodynamic properties of α-uranium from 0 to 900 K and 0–100 GPa were calculated with the quasi-harmonic Debye model. Volume, bulk modulus, entropy, Debye temperature, thermal expansion coefficient and the heat capacity of α-uranium were calculated. The calculated results show that the bulk modulus and Debye temperature increase with the increasing pressure at a given temperature while decreasing with the increasing temperature at a given pressure. Volume, entropy, thermal expansion coefficient and the heat capacity decrease with the increasing pressure while increasing with the increasing temperature. The theoretical results of entropy, Debye temperature, thermal expansion coefficient and the heat capacity show good agreement with the general trends of the experimental values. The constant-volume heat capacity shows typical Debye T"3 power-law behavior at low temperature limit and approaches to the classical asymptotic Dulong-Petit limit at high temperature limit. - Highlights: • Thermodynamic properties of α-U were predicted systematically with quasi-harmonic Debye model. • Summarizations of the corresponding experimental and theoretical results have been made for the EOS and other thermodynamic parameters. • The calculated thermodynamic properties show good agreement with the experimental results in general trends.
Thermodynamic properties of α-uranium
Energy Technology Data Exchange (ETDEWEB)
Ren, Zhiyong; Wu, Jun; Ma, Rong; Hu, Guichao; Luo, Chao, E-mail: luochaoboss@sohu.com
2016-11-15
The lattice constants and equilibrium atomic volume of α-uranium were calculated by Density Functional Theory (DFT). The first principles calculation results of the lattice for α-uranium are in agreement with the experimental results well. The thermodynamic properties of α-uranium from 0 to 900 K and 0–100 GPa were calculated with the quasi-harmonic Debye model. Volume, bulk modulus, entropy, Debye temperature, thermal expansion coefficient and the heat capacity of α-uranium were calculated. The calculated results show that the bulk modulus and Debye temperature increase with the increasing pressure at a given temperature while decreasing with the increasing temperature at a given pressure. Volume, entropy, thermal expansion coefficient and the heat capacity decrease with the increasing pressure while increasing with the increasing temperature. The theoretical results of entropy, Debye temperature, thermal expansion coefficient and the heat capacity show good agreement with the general trends of the experimental values. The constant-volume heat capacity shows typical Debye T{sup 3} power-law behavior at low temperature limit and approaches to the classical asymptotic Dulong-Petit limit at high temperature limit. - Highlights: • Thermodynamic properties of α-U were predicted systematically with quasi-harmonic Debye model. • Summarizations of the corresponding experimental and theoretical results have been made for the EOS and other thermodynamic parameters. • The calculated thermodynamic properties show good agreement with the experimental results in general trends.
The calculation of thermodynamic properties of molecules
DEFF Research Database (Denmark)
van Speybroeck, Veronique; Gani, Rafiqul; Meier, Robert Johan
2010-01-01
Thermodynamic data are key in the understanding and design of chemical processes. Next to the experimental evaluation of such data, computational methods are valuable and sometimes indispensable tools in obtaining heats of formation and Gibbs free energies. The major toolboxes to obtain such quan......Thermodynamic data are key in the understanding and design of chemical processes. Next to the experimental evaluation of such data, computational methods are valuable and sometimes indispensable tools in obtaining heats of formation and Gibbs free energies. The major toolboxes to obtain...... molecules the combination of group contribution methods with group additive values that are determined with the best available computational ab initio methods seems to be a viable alternative to obtain thermodynamic properties near chemical accuracy. New developments and full use of existing tools may lead...
Thermodynamic properties of pressurized PH3 superconductor
Koka, S.; Rao, G. Venugopal
2018-05-01
The paper presents the superconducting thermodynamic functions determined for pressurized phosphorus trihydride (PH3). In particular, free energy difference ΔF, thermodynamic critical field Hc, specific heat etc. have been calculated using analytical expressions. The calculations were performed in the frame work of the strong-coupling formalism. The obtained dimensionless parameters: RΔ ≡ 2Δ(0)/kBTc, RC ≡ ΔC(Tc)/CN(Tc) and RH≡TcCN(Tc)/Hc2(0) are 4.05, 1.96 and 0.156 respectively, which significantly differ from the values arising from the BCS theory of superconductivity. The thermodynamic properties strongly depend on the depairing electron correlations and retardation effects.
Consistent thermodynamic properties of lipids systems
DEFF Research Database (Denmark)
Cunico, Larissa; Ceriani, Roberta; Sarup, Bent
different pressures, with azeotrope behavior observed. Available thermodynamic consistency tests for TPx data were applied before performing parameter regressions for Wilson, NRTL, UNIQUAC and original UNIFAC models. The relevance of enlarging experimental databank of lipids systems data in order to improve......Physical and thermodynamic properties of pure components and their mixtures are the basic requirement for process design, simulation, and optimization. In the case of lipids, our previous works[1-3] have indicated a lack of experimental data for pure components and also for their mixtures...... the performance of predictive thermodynamic models was confirmed in this work by analyzing the calculated values of original UNIFAC model. For solid-liquid equilibrium (SLE) data, new consistency tests have been developed [2]. Some of the developed tests were based in the quality tests proposed for VLE data...
Thermodynamical properties of 56Fe
International Nuclear Information System (INIS)
Tavukcu, E.; Becker, J. A.; Bernstein, L. A.; Garrett, P. E.; Younes, W.; Guttormsen, M.; Rekstad, J.; Siem, S.; Mitchell, G. E.; Schiller, A.; Voinov, A.
2003-01-01
Average nuclear level densities close to the nuclear binding energy in 56Fe and 57Fe are extracted from primary γ-ray spectra. A step structure is observed in the level density for both isotopes, and is interpreted as breaking of Cooper pairs. Thermal properties of 56Fe are studied within the statistical canonical ensemble. The experimental heat capacity in 56Fe is compared with the theoretical heat capacity calculated within the shell model Monte Carlo approach
Macroscopic behavior and microscopic magnetic properties of nanocarbon
Energy Technology Data Exchange (ETDEWEB)
Lähderanta, E., E-mail: Erkki.Lahderanta@lut.fi [Lappeenranta University of Technology, PO Box 20, FIN-53851 Lappeenranta (Finland); Ryzhov, V.A. [Lappeenranta University of Technology, PO Box 20, FIN-53851 Lappeenranta (Finland); Petersburg Nuclear Physics Institute, NRC “Kurchatov Institute”, Orlova Coppice, Gatchina, Leningrad province 188300 (Russian Federation); Lashkul, A.V. [Lappeenranta University of Technology, PO Box 20, FIN-53851 Lappeenranta (Finland); Galimov, D.M. [Lappeenranta University of Technology, PO Box 20, FIN-53851 Lappeenranta (Finland); South Ural State University, 454080 Chelyabinsk (Russian Federation); Titkov, A.N. [Lappeenranta University of Technology, PO Box 20, FIN-53851 Lappeenranta (Finland); A. F. Ioffe Physico-Technical Institute, 194021 St. Petersburg (Russian Federation); Matveev, V.V. [Lappeenranta University of Technology, PO Box 20, FIN-53851 Lappeenranta (Finland); Saint-Petersburg State University, Saint-Petersburg 198504 (Russian Federation); Mokeev, M.V. [Institute of Macromolecular Compounds, Russian Academy of Sciences, St. Petersburg (Russian Federation); Kurbakov, A.I. [Petersburg Nuclear Physics Institute, NRC “Kurchatov Institute”, Orlova Coppice, Gatchina, Leningrad province 188300 (Russian Federation); Lisunov, K.G. [Lappeenranta University of Technology, PO Box 20, FIN-53851 Lappeenranta (Finland); Institute of Applied Physics ASM, Academiei Str., 5, MD 2028 Kishinev (Moldova, Republic of)
2015-06-01
Here are presented investigations of powder and glass-like samples containing carbon nanoparticles, not intentionally doped and doped with Ag, Au and Co. The neutron diffraction study reveals an amorphous structure of the samples doped with Au and Co, as well as the magnetic scattering due to a long-range FM order in the Co-doped sample. The composition and molecular structure of the sample doped with Au is clarified with the NMR investigations. The temperature dependence of the magnetization, M (T), exhibits large irreversibility in low fields of B=1–7 mT. M (B) saturates already above 2 T at high temperatures, but deviates from the saturation behavior below ~50 (150 K). Magnetic hysteresis is observed already at 300 K and exhibits a power-law temperature decay of the coercive field, B{sub c} (T). The macroscopic behavior above is typical of an assembly of partially blocked magnetic nanoparticles. The values of the saturation magnetization, M{sub s}, and the blocking temperature, T{sub b}, are obtained as well. However, the hysteresis loop in the Co-doped sample differs from that in other samples, and the values of B{sub c} and M{sub s} are noticeably increased. - Highlights: • We have investigated powder and glassy samples with carbon nanoparticles. • They include an undoped sample and those doped with Ag, Au and Co. • Neutron diffraction study reveals amorphous structure of Au- and Co-doped samples. • Composition and molecular structure of Au-doped sample was investigated with NMR. • Magnetic behavior is typical of an assembly of partially blocked magnetic nanoparticles.
Macroscopic behavior and microscopic magnetic properties of nanocarbon
International Nuclear Information System (INIS)
Lähderanta, E.; Ryzhov, V.A.; Lashkul, A.V.; Galimov, D.M.; Titkov, A.N.; Matveev, V.V.; Mokeev, M.V.; Kurbakov, A.I.; Lisunov, K.G.
2015-01-01
Here are presented investigations of powder and glass-like samples containing carbon nanoparticles, not intentionally doped and doped with Ag, Au and Co. The neutron diffraction study reveals an amorphous structure of the samples doped with Au and Co, as well as the magnetic scattering due to a long-range FM order in the Co-doped sample. The composition and molecular structure of the sample doped with Au is clarified with the NMR investigations. The temperature dependence of the magnetization, M (T), exhibits large irreversibility in low fields of B=1–7 mT. M (B) saturates already above 2 T at high temperatures, but deviates from the saturation behavior below ~50 (150 K). Magnetic hysteresis is observed already at 300 K and exhibits a power-law temperature decay of the coercive field, B c (T). The macroscopic behavior above is typical of an assembly of partially blocked magnetic nanoparticles. The values of the saturation magnetization, M s , and the blocking temperature, T b , are obtained as well. However, the hysteresis loop in the Co-doped sample differs from that in other samples, and the values of B c and M s are noticeably increased. - Highlights: • We have investigated powder and glassy samples with carbon nanoparticles. • They include an undoped sample and those doped with Ag, Au and Co. • Neutron diffraction study reveals amorphous structure of Au- and Co-doped samples. • Composition and molecular structure of Au-doped sample was investigated with NMR. • Magnetic behavior is typical of an assembly of partially blocked magnetic nanoparticles
NMR studies of macroscopic and microscopic properties of liquid crystals
International Nuclear Information System (INIS)
Hughes, J.R.
1998-03-01
The work presented is concerned with studies of orientational order in liquid crystals and the behaviour of certain mesophases. The experimental technique used in common with all the work is deuterium NMR spectroscopy. Much of the work involves studies of the orientational order of deuteriated solute molecules dissolved in liquid crystal solvents. Chapter 1 gives an introduction to liquid crystals followed by a quantitative description of orientational order. Deuterium NMR in liquid crystals is described and an outline of the molecular field theory behind the orientational order of a rigid, biaxial solute in a uniaxial mesophase is given. In Chapter 2 a novel type of mesophase induction is studied using NMR, where a solute induces up to two extra phases in a discotic mesogen depending on its concentration. The purpose of this work is to try to gain an understanding into the mechanism of the phase induction involved. Chapter 3 is concerned primarily with the macroscopic behaviour of the nematic phase formed by a semi-rigid main-chain polymer in solution. Of particular interest is the study of the reorientation of the monodomain, once the director has been rotated with respect to the magnetic field of the NMR spectrometer. A mesogen which has been claimed to exhibit a biaxial nematic phase is studied in Chapter 4, in order to determine the symmetry of the phase using NMR. Finally, Chapter 5 deals with the differing behaviour of a liquid crystal monomer and its dimer dissolved in common nematic solvents in order to determine whether this agrees with molecular field theory. (author)
Modeling the thermodynamic properties of plutonium
International Nuclear Information System (INIS)
Stan, Marius
2000-01-01
The golden dream of any modeling enterprise is to predict the properties of the studied system in a new and often 'hostile' environment. The basis of this kind of work is the careful, accurate assessment of the system properties in normal conditions. What 'normal conditions' means for plutonium is an interesting question itself. This work is dedicated to modeling only a fraction of the remarkable characteristics of this 'mysterious' material, that is the thermodynamic properties of its six allotropic phases (seven under pressure), the liquid phase, and the vapor phase. The goal is to provide valuable information for the calculation of alloyed plutonium phase diagrams
The thermodynamic properties of benzothiazole and benzoxazole
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.
Thermodynamic Properties and Thermodynamic Geometries of Black p-Branes
International Nuclear Information System (INIS)
Yi-Huan Wei; Xiao Cui; Jia-Xin Zhao
2016-01-01
The heat capacity and the electric capacitance of the black p-branes (BPB) are generally defined, then they are calculated for some special processes. It is found that the Ruppeiner thermodynamic geometry of BPB is flat. Finally, we give some discussions for the flatness of the Ruppeiner thermodynamic geometry of BPB and some black holes. (paper)
Laser modification of macroscopic properties of metal surface layer
Kostrubiec, Franciszek
1995-03-01
Surface laser treatment of metals comprises a number of diversified technological operations out of which the following can be considered the most common: oxidation and rendering surfaces amorphous, surface hardening of steel, modification of selected physical properties of metal surface layers. In the paper basic results of laser treatment of a group of metals used as base materials for electric contacts have been presented. The aim of the study was to test the usability of laser treatment from the viewpoint of requirements imposed on materials for electric contacts. The results presented in the paper refer to two different surface treatment technologies: (1) modification of infusible metal surface layer: tungsten and molybdenum through laser fusing of their surface layer and its crystallization, and (2) modification of surface layer properties of other metals through laser doping of their surface layer with foreign elements. In the paper a number of results of experimental investigations obtained by the team under the author's supervision are presented.
Thermodynamic Properties of Actinides and Actinide Compounds
Konings, Rudy J. M.; Morss, Lester R.; Fuger, Jean
The necessity of obtaining accurate thermodynamic quantities for the actinide elements and their compounds was recognized at the outset of the Manhattan Project, when a dedicated team of scientists and engineers initiated the program to exploit nuclear energy for military purposes. Since the end of World War II, both fundamental and applied objectives have motivated a great deal of further study of actinide thermodynamics. This chapter brings together many research papers and critical reviews on this subject. It also seeks to assess, to systematize, and to predict important properties of the actinide elements, ions, and compounds, especially for species in which there is significant interest and for which there is an experimental basis for the prediction.
Correlation of macroscopic material properties with microscopic nuclear data
International Nuclear Information System (INIS)
Simons, R.L.
1981-01-01
Two primary irradiation-induced changes occur during neutron irradiation: the displacement of atoms forming crystal defects and the transmutation of atoms into either gaseous or solid products. The material scientist studying irradiation damage to material by fusion-produced neutrons is faced with several questions: Is the nature of high-energy (14-MeV) displacement damage the same as or different from that caused by fission neutrons (< 2 MeV). How do the high helium concentrations expected in a fusion environment affect the material properties. What effects do solid transmutation products have on the behavior of the irradiated materials. In the past few years, much work has been done to answer these questions. This paper reviews recent work in this area
Thermodynamic properties of mixtures of liquids
International Nuclear Information System (INIS)
Benedetti, A.V.; Cilense, M.; Vollet, D.
1982-01-01
The molar excess enthalpy (H sup(-E)) of water-ethanol has been measured at 298.15, 306.85, 313.95 and 319.75 K. The mixtures are exothermics at studied temperatures with minimum values of -785, -655, -555 and -490 J. mol -1 respectively, at value of X 2 about 0.16. The other thermodynamics properties have been obtained from experimental data and data from literature. The results are interpreted qualitatively by considering molecular interactions in solution. (Author) [pt
Thermodynamic and transport properties of liquid gallium
International Nuclear Information System (INIS)
Park, H.Y.; Jhon, M.S.
1982-01-01
The significant structure theory of liquids has been successfully applied to liquid gallium. In this work, we have assumed that two structures exist simultaneously in liquid gallium. One is considerec as loosely close packed β-Ga-like structure and the other is remainder of solid α-Ga or α-Ga-like structure. This two structural model is introduced to construct the liquid partition function. Using the partition function, the thermodynamic and transport properties are calculated ever a wide temperature range. The calculated results are quite satisfactory when compared with the experimental results. (Author)
Thermodynamic properties of particles with intermediate statistics
International Nuclear Information System (INIS)
Joyce, G.S.; Sarkar, S.; Spal/ek, J.; 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 α 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 α lies in the range 0 V of the D-dimensional excluson gas. The low-temperature series for the thermodynamic properties illustrate the pseudofermion nature of exclusons. copyright 1996 The American Physical Society
Keshavarzi, Ezat; Kamalvand, Mohammad
2009-04-23
The structure and properties of fluids confined in nanopores may show a dramatic departure from macroscopic bulk fluids. The main reason for this difference lies in the influence of system walls. In addition to the entropic wall effect, system walls can significantly change the energy of the confined fluid compared to macroscopic bulk fluids. The energy effect of the walls on a nanoconfined fluid appears in two forms. The first effect is the cutting off of the intermolecular interactions by the walls, which appears for example in the integrals for calculation of the thermodynamic properties. The second wall effect involves the wall-molecule interactions. In such confined fluids, the introduction of wall forces and the competition between fluid-wall and fluid-fluid forces could lead to interesting thermodynamic properties, including new kinds of phase transitions not observed in the macroscopic fluid systems. In this article, we use the perturbative fundamental measure density functional theory to study energy effects on the structure and properties of a hard core two-Yukawa fluid confined in a nanoslit. Our results show the changes undergone by the structure and phase transition of the nanoconfined fluids as a result of energy effects.
Sialic acid-triggered macroscopic properties switching on a smart polymer surface
Xiong, Yuting; Li, Minmin; Wang, Hongxi; Qing, Guangyan; Sun, Taolei
2018-01-01
Constructing smart surfaces with responsive polymers capable of dynamically and reversibly changing their chemical and physical properties by responding to the recognition of biomolecules remains a challenging task. And, the key to achieving this purpose relies on the design of polymers to precisely interact with the target molecule and successfully transform the interaction signal into tunable macroscopic properties, further achieve special bio-functions. Herein, inspired by carbohydrate-carbohydrate interaction (CCI) in life system, we developed a three-component copolymer poly(NIPAAm-co-PT-co-Glc) bearing a binding unit glucose (Glc) capable of recognizing sialic acid, a type of important molecular targets for cancer diagnosis and therapy, and reported the sialic acid triggered macroscopic properties switching on this smart polymer surface. Detailed mechanism studies indicated that multiple hydrogen bonding interactions between Glc unit and Neu5Ac destroyed the initial hydrogen bond network of the copolymer, leading to a reversible "contraction-to-swelling" conformational transition of the copolymer chains, accompanied with distinct macroscopic property switching (i.e., surface wettability, morphology, stiffness) of the copolymer film. And these features enabled this copolymer to selectively capture sialic acid-containing glycopeptides from complex protein samples. This work provides an inspiration for the design of novel smart polymeric materials with sensitive responsiveness to sialic acid, which would promote the development of sialic acid-specific bio-devices and drug delivery systems.
Size- and shape-dependent surface thermodynamic properties of nanocrystals
Fu, Qingshan; Xue, Yongqiang; Cui, Zixiang
2018-05-01
As the fundamental properties, the surface thermodynamic properties of nanocrystals play a key role in the physical and chemical changes. However, it remains ambiguous about the quantitative influence regularities of size and shape on the surface thermodynamic properties of nanocrystals. Thus by introducing interface variables into the Gibbs energy and combining Young-Laplace equation, relations between the surface thermodynamic properties (surface Gibbs energy, surface enthalpy, surface entropy, surface energy and surface heat capacity), respectively, and size of nanocrystals with different shapes were derived. Theoretical estimations of the orders of the surface thermodynamic properties of nanocrystals agree with available experimental values. Calculated results of the surface thermodynamic properties of Au, Bi and Al nanocrystals suggest that when r > 10 nm, the surface thermodynamic properties linearly vary with the reciprocal of particle size, and when r < 10 nm, the effect of particle size on the surface thermodynamic properties becomes greater and deviates from linear variation. For nanocrystals with identical equivalent diameter, the more the shape deviates from sphere, the larger the surface thermodynamic properties (absolute value) are.
DERIVED THERMODYNAMIC PROPERTIES OF [o-XYLENE OR p ...
African Journals Online (AJOL)
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This paper is a continuation of our earlier work related to the study of thermodynamic properties of binary and ternary mixtures [1-6]. Reliable data on phase behavior and thermodynamic excess properties of multi component fluid mixtures are necessary for the proper design of synthesis and separation processes of the ...
Introduction to applied thermodynamics
Helsdon, R M; Walker, G E
1965-01-01
Introduction to Applied Thermodynamics is an introductory text on applied thermodynamics and covers topics ranging from energy and temperature to reversibility and entropy, the first and second laws of thermodynamics, and the properties of ideal gases. Standard air cycles and the thermodynamic properties of pure substances are also discussed, together with gas compressors, combustion, and psychrometry. This volume is comprised of 16 chapters and begins with an overview of the concept of energy as well as the macroscopic and molecular approaches to thermodynamics. The following chapters focus o
Universal relation for size dependent thermodynamic properties of metallic nanoparticles.
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. This journal is © the Owner Societies 2011
Magnetic properties and macroscopic heterogeneity of FeCoNbB Hitperms
Energy Technology Data Exchange (ETDEWEB)
Butvin, Pavol [Institute of Physics, Slovak Academy of Sciences, Dubravska cesta 9, 845 11 Bratislava (Slovakia)], E-mail: fyzipbut@savba.sk; Butvinova, Beata [Institute of Physics, Slovak Academy of Sciences, Dubravska cesta 9, 845 11 Bratislava (Slovakia); Sitek, Jozef; Degmova, Jarmila [Department of Nuclear Physics and Technology, FEI, Slovak University of Technology, Ilkovicova 3, 812 19 Bratislava (Slovakia); Vlasak, Gabriel; Svec, Peter; Janickovic, Dusan [Institute of Physics, Slovak Academy of Sciences, Dubravska cesta 9, 845 11 Bratislava (Slovakia)
2008-03-15
Nanocrystalline ribbons of Fe{sub 81-x}Co{sub x}Nb{sub 7}B{sub 12} (where x ranges from 0 to 40.5 at%) Hitperm alloys have been investigated as to their basic magnetic properties and the influence of the macroscopic heterogeneity. Different crystalline share at surfaces compared with the volume average is observed by conversion electron Moessbauer spectroscopy (CEMS) and Moessbauer spectroscopy (MS), respectively. This marks the presence of macroscopic heterogeneity in these Hitperms. The heterogeneity is generally more significant in Ar-annealed samples than in the vacuum-annealed ones. The characteristic slant hysteresis loops (hard-ribbon-axis) are seen as a rule with few exceptions. An inspection of hysteresis loop response of resin potted samples shows that the surfaces bi-axially squeeze the ribbon interior in heterogeneous Hitperms when the ribbons cool down after annealing. Certain compositions show macroscopic viscous flow prior to crystallization so the heterogeneity gets another chance to induce anisotropy during annealing. The induction attains 1.5 T but saturates poorly due to the heterogeneity and the ensuing anisotropy. Moreover the heterogeneity appears to hamper the crystallization within the ribbon interior. Unlike Finemets, the density of these Hitperms show no pronounced trend with annealing.
Magnetic properties and macroscopic heterogeneity of FeCoNbB Hitperms
Butvin, Pavol; Butvinová, Beata; Sitek, Jozef; Degmová, Jarmila; Vlasák, Gabriel; Švec, Peter; Janičkovič, Dušan
Nanocrystalline ribbons of Fe 81-xCo xNb 7B 12 (where x ranges from 0 to 40.5 at%) Hitperm alloys have been investigated as to their basic magnetic properties and the influence of the macroscopic heterogeneity. Different crystalline share at surfaces compared with the volume average is observed by conversion electron Mössbauer spectroscopy (CEMS) and Mössbauer spectroscopy (MS), respectively. This marks the presence of macroscopic heterogeneity in these Hitperms. The heterogeneity is generally more significant in Ar-annealed samples than in the vacuum-annealed ones. The characteristic slant hysteresis loops (hard-ribbon-axis) are seen as a rule with few exceptions. An inspection of hysteresis loop response of resin potted samples shows that the surfaces bi-axially squeeze the ribbon interior in heterogeneous Hitperms when the ribbons cool down after annealing. Certain compositions show macroscopic viscous flow prior to crystallization so the heterogeneity gets another chance to induce anisotropy during annealing. The induction attains 1.5 T but saturates poorly due to the heterogeneity and the ensuing anisotropy. Moreover the heterogeneity appears to hamper the crystallization within the ribbon interior. Unlike Finemets, the density of these Hitperms show no pronounced trend with annealing.
CH-π Interaction Driven Macroscopic Property Transition on Smart Polymer Surface
Li, Minmin; Qing, Guangyan; Xiong, Yuting; Lai, Yuekun; Sun, Taolei
2015-10-01
Life systems have evolved to utilize weak noncovalent interactions, particularly CH-π interaction, to achieve various biofunctions, for example cellular communication, immune response, and protein folding. However, for artificial materials, it remains a great challenge to recognize such weak interaction, further transform it into tunable macroscopic properties and realize special functions. Here we integrate monosaccharide-based CH-π receptor capable of recognizing aromatic peptides into a smart polymer with three-component “Recognition-Mediating-Function” design, and report the CH-π interaction driven surface property switching on smart polymer film, including wettability, adhesion, viscoelasticity and stiffness. Detailed studies indicate that, the CH-π interaction induces the complexation between saccharide unit and aromatic peptide, which breaks the initial amphiphilic balance of the polymer network, resulting in contraction-swelling conformational transition for polymer chains and subsequent dramatic switching in surface properties. This work not only presents a new approach to control the surface property of materials, but also points to a broader research prospect on CH-π interaction at a macroscopic level.
Thermodynamic Properties of Manganese and Molybdenum
International Nuclear Information System (INIS)
Desai, P.D.
1987-01-01
This work reviews and discusses the data on the various thermodynamic properties of manganese and molybdenum available through March 1985. These include heat capacity, enthalpy, enthalpy of transitions and melting, vapor pressure, and enthalpy of vaporization. The existing data have been critically evaluated and analyzed. The recommended values for the heat capacity, enthalpy, entropy, and Gibbs energy function from 0.5 to 2400 K for manganese and from 0.4 to 5000 K for molybdenum have been generated, as have heat capacity values for supercooled β-Mn and for γ-Mn below 298.15 K. The recommended values for vapor pressure cover the temperature range from 298.15 to 2400 K for manganese and from 298.15 to 5000 K for molybdenum. These values are referred to temperatures based on IPTS-1968. The uncertainties in the recommended values of the heat capacity range from +-3% to +-5% for manganese and from +-1.5% to +-3% for molybdenum
[Relationships between microscope structure and thermodynamic properties
International Nuclear Information System (INIS)
Wu, R.S.; Lee, L.L.; Cochran, D.
1990-01-01
This paper exhibits on the molecular level, the relationships between the microscopic structure and thermodynamic properties of dilute supercritical solutions by application of the integral equation theories for molecular distribution functions. To solve the integral equations, the authors use Baxter's Wiener-Hopf factorization of the Ornstein-Zernike equations and then apply this method to binary Lennard-Jones mixtures. A number of closure relations have been used: such as the Percus-Yevick (PY), the reference hypernetted chain (RHNC), the hybrid mean spherical approximation (HMSA), and the reference interaction-site (RISM) methods. The authors examine the microstructures of several important classes of supercritical mixtures, including the usual attractive-type and the less known repulsive-type solutions. The clustering of solvent molecules for solvent-solute structures in the attractive mixtures and, correspondingly, the solvent cavitation in the repulsive mixtures are clearly demonstrated. These are shown to be responsible for the large negative growth of the solute partial molar volumes in the attractive case and the positive growth in the repulsive case
Thermodynamical and dynamical properties of charged BTZ black holes
Energy Technology Data Exchange (ETDEWEB)
Tang, Zi-Yu; Wang, Bin [Shanghai Jiao Tong University, Department of Physics and Astronomy, Center for Astronomy and Astrophysics, Shanghai (China); Zhang, Cheng-Yong [Peking University, Center for High-Energy Physics, Beijing (China); Kord Zangeneh, Mahdi [Shanghai Jiao Tong University, Department of Physics and Astronomy, Center for Astronomy and Astrophysics, Shanghai (China); Shahid Chamran University of Ahvaz, Physics Department, Faculty of Science, Ahvaz (Iran, Islamic Republic of); Research Institute for Astronomy and Astrophysics of Maragha (RIAAM)-Maragha, P. O. Box: 55134-441, Maragha (Iran, Islamic Republic of); Shiraz University, Physics Department and Biruni Observatory, College of Sciences, Shiraz (Iran, Islamic Republic of); Saavedra, Joel [Pontificia Universidad Catolica de Valparaiso, Instituto de Fisica, Valparaiso (Chile)
2017-06-15
We investigate the spacetime properties of BTZ black holes in the presence of the Maxwell field and Born-Infeld field and find rich properties in the spacetime structures when the model parameters are varied. Employing Landau-Lifshitz theory, we examine the thermodynamical phase transition in the charged BTZ black holes. We further study the dynamical perturbation in the background of the charged BTZ black holes and find different properties in the dynamics when the thermodynamical phase transition occurs. (orig.)
DISTRIBUTION OF PARASTATISTICS FUNCTIONS: AN OVERVIEW OF THERMODYNAMICS PROPERTIES
Directory of Open Access Journals (Sweden)
R. Yosi Aprian Sari
2016-05-01
Full Text Available This study aims to determine the thermodynamic properties of the parastatistics system of order two. The thermodynamic properties to be searched include the Grand Canonical Partition Function (GCPF Z, and the average number of particles N. These parastatistics systems is in a more general form compared to quantum statistical distribution that has been known previously, i.e.: the Fermi-Dirac (FD and Bose-Einstein (BE. Starting from the recursion relation of grand canonical partition function for parastatistics system of order two that has been known, recuresion linkages for some simple thermodynamic functions for parastatistics system of order two are derived. The recursion linkages are then used to calculate the thermodynamic functions of the model system of identical particles with limited energy levels which is similar to the harmonic oscillator. From these results we concluded that from the Grand Canonical Partition Function (GCPF, Z, the thermodynamics properties of parastatistics system of order two (paraboson and parafermion can be derived and have similar shape with parastatistics system of order one (Boson and Fermion. The similarity of the graph shows similar thermodynamic properties. Keywords: parastatistics, thermodynamic properties
Induction of novel macroscopic properties by local symmetry violations in spin-spiral multiferroics
Meier, D.; Leo, N.; Becker, P.; Bohaty, L.; Ramesh, R.; Fiebig, M.
2011-03-01
Incommensurate (IC) structures are omnipresent in strongly correlated electron systems as high-TC superconductors, CMR manganites, as well as multiferroics. In each case they are origin of a pronounced symmetry reduction reflecting the complexity of the underlying microscopic interactions. Macroscopically, this can lead to new phases and possibilities to gain control of the host material. Here we report how the IC nature of a spin-spiral multiferroic induces new physical properties by renormalizing the relevant length scales of the system. Local symmetry violations directly manifest in the macroscopic response of the material and co-determine the multiferroic order giving rise to additional domain states. These usually hidden degrees of freedom become visible when non-homogenous fields are applied and condition for instance the second harmonic generation. Our study shows that incommensurabilities play a vital role in the discussion of the physical properties of multiferroics -- they represent a key ingredient for further enhancing the functionality of this class of materials. This work was supported by the DFG through the SFB 608. D.M. thanks the AvH for financial support.
Thermodynamic properties of the DUPIC fuel and its performance
Energy Technology Data Exchange (ETDEWEB)
Park, Kwang Heon; Kim, Hee Moon [Kyung Hee Univ., Seoul (Korea, Republic of)
1997-07-01
This study describes thermodynamic properties of DUPIC fuel and performance. In initial state, DUPIC fuel which contains fissile materials is different from general nuclear fuel. So this study analyzed oxygen potential, thermal conductivity and specific heat of the DUPIC fuel.
Ammonia-water system : Part I. Thermodynamic properties
International Nuclear Information System (INIS)
Goomer, N.C.; Dave, S.M.; Sadhukhan, H.K.
1980-01-01
The various thermodynamic properties which have direct bearing on design calculations and separation factor calculations for gaseous ammonia water system have been calculated and compiled in tabular form for easy reference. (auth.)
Thermodynamic properties of cesium in the gaseous phase
International Nuclear Information System (INIS)
Vargaftik, N.B.; Voljak, L.D.; Stepanov, V.G.
1985-01-01
Tables of the thermodynamic properties of caesium in the gaseous phase are presented for a wide range of temperature and pressure. The thermodynamic properties include: enthalpy, entropy, specific heat, specific volume, sound velocity and compressibility factor. The values have been calculated from pressure-volume-temperature measurements by various authors. Experimental apparatus to determine these measurements is described, together with an outline of the method employed to process the results, and the error estimates. (U.K.)
Theoretical investigation of the thermodynamic properties of metallic thin films
International Nuclear Information System (INIS)
Hung, Vu Van; Phuong, Duong Dai; Hoa, Nguyen Thi; Hieu, Ho Khac
2015-01-01
The thermodynamic properties of metallic thin films with face-centered cubic structure at ambient conditions were investigated using the statistical moment method including the anharmonicity effects of thermal lattice vibrations. The analytical expressions of Helmholtz free energy, lattice parameter, linear thermal expansion coefficient, specific heats at the constant volume and constant pressure were derived in terms of the power moments of the atomic displacements. Numerical calculations of thermodynamic properties have been performed for Au and Al thin films and compared with those of bulk metals. This research proposes that thermodynamic quantities of thin films approach the values of bulk when the thickness of thin film is about 70 nm. - Highlights: • Thermodynamic properties of thin films were investigated using the moment method. • Expressions of Helmholtz energy, expansion coefficient, specific heats were derived. • Calculations for Au, Al thin films were performed and compared with those of bulks
Theoretical investigation of the thermodynamic properties of metallic thin films
Energy Technology Data Exchange (ETDEWEB)
Hung, Vu Van [Vietnam Education Publishing House, 81 Tran Hung Dao, Hanoi (Viet Nam); Phuong, Duong Dai [Hanoi National University of Education, 136 Xuan Thuy, Hanoi (Viet Nam); Hoa, Nguyen Thi [University of Transport and Communications, Lang Thuong, Dong Da, Hanoi (Viet Nam); Hieu, Ho Khac, E-mail: hieuhk@duytan.edu.vn [Institute of Research and Development, Duy Tan University, K7/25 Quang Trung, Danang (Viet Nam)
2015-05-29
The thermodynamic properties of metallic thin films with face-centered cubic structure at ambient conditions were investigated using the statistical moment method including the anharmonicity effects of thermal lattice vibrations. The analytical expressions of Helmholtz free energy, lattice parameter, linear thermal expansion coefficient, specific heats at the constant volume and constant pressure were derived in terms of the power moments of the atomic displacements. Numerical calculations of thermodynamic properties have been performed for Au and Al thin films and compared with those of bulk metals. This research proposes that thermodynamic quantities of thin films approach the values of bulk when the thickness of thin film is about 70 nm. - Highlights: • Thermodynamic properties of thin films were investigated using the moment method. • Expressions of Helmholtz energy, expansion coefficient, specific heats were derived. • Calculations for Au, Al thin films were performed and compared with those of bulks.
Thermodynamic and transport properties of sodium liquid and vapor
International Nuclear Information System (INIS)
Fink, J.K.; Leibowitz, L.
1995-01-01
Data have been reviewed to obtain thermodynamically consistent equations for thermodynamic and transport properties of saturated sodium liquid and vapor. Recently published Russian recommendations and results of equation of state calculations on thermophysical properties of sodium have been included in this critical assessment. Thermodynamic properties of sodium liquid and vapor that have been assessed include: enthalpy, heat capacity at constant pressure, heat capacity at constant volume, vapor pressure, boiling point, enthalpy of vaporization, density, thermal expansion, adiabatic and isothermal compressibility, speed of sound, critical parameters, and surface tension. Transport properties of liquid sodium that have been assessed include: viscosity and thermal conductivity. For each property, recommended values and their uncertainties are graphed and tabulated as functions of temperature. Detailed discussions of the analyses and determinations of the recommended equations include comparisons with recommendations given in other assessments and explanations of consistency requirements. The rationale and methods used in determining the uncertainties in the recommended values are also discussed
Directory of Open Access Journals (Sweden)
Zhenqing Wang
2013-01-01
Full Text Available The effect of nanosilica contents on mechanical properties of the epoxy matrix with some nanoparticle aggregations was studied in macroscopic experiments and nanoscale simulation, particularly with regard to the effective modulus and ultimate stress. Three analytical models were used to obtain the effective elastic modulus of nanoparticle-reinforced composites. Based on Monte-Carlo method, the special program for the automatic generation of 2D random distribution particles without overlapping was developed for nanocomposite modeling. Weight fractions of nanoparticles were converted to volume fractions, in order to coordinate the content unit in the simulation. In numerical analysis, the weak interface strengthening and toughening mechanism was adopted. Virtual crack closure technique (VCCT and extended finite element method (XFEM were used to simulate phenomena of nanoparticle debonding and matrix crack growth. Experimental and simulation results show a good agreement with each other. By way of simulation, the weak interface toughening and strengthening mechanism of nanocomposites is confirmed.
Thermodynamic properties of vitamin B2
International Nuclear Information System (INIS)
Knyazev, A.V.; Letyanina, I.A.; Plesovskikh, A.S.; Smirnova, N.N.; Knyazeva, S.S.
2014-01-01
Graphical abstract: - Highlights: • Temperature dependence of heat capacity of vitamin B 2 has been measured by precision adiabatic vacuum calorimetry. • The thermodynamic functions of the vitamin B 2 have been determined for the range from T → 0 to 322 K. • The energy of combustion of the riboflavin has been measured at 298.15 K. • The enthalpy of combustion Δ c H° and the thermodynamic parameters Δ f H°, Δ f S°, Δ f G° have been calculated. - Abstract: In the present work temperature dependence of heat capacity of vitamin B 2 (riboflavin) has been measured for the first time in the range from 6 to 322 K by precision adiabatic vacuum calorimetry. Based on the experimental data, the thermodynamic functions of the vitamin B 2 , namely, the heat capacity, enthalpy H°(T) − H°(0), entropy S°(T) − S°(0) and Gibbs function G°(T) − H°(0) have been determined for the range from T → 0 to 322 K. The value of the fractal dimension D in the function of multifractal generalization of Debye's theory of the heat capacity of solids was estimated and the character of heterodynamics of structure was detected. In a calorimeter with a static bomb and an isothermal shield, the energy of combustion of the riboflavin has been measured at 298.15 K. The enthalpy of combustion Δ c H° and the thermodynamic parameters Δ f H°, Δ f S°, Δ f G° and of reaction of formation of the riboflavin from simple substances at T = 298.15 K and p = 0.1 MPa have been calculated
Sun, Xuemei; Chen, Tao; Yang, Zhibin; Peng, Huisheng
2013-02-19
To improve the practical application of carbon nanotubes, it is critically important to extend their physical properties from the nanoscale to the macroscopic scale. Recently, chemists aligned continuous multiwalled carbon nanotube (MWCNT) sheets and fibers to produce materials with high mechanical strength and electrical conductivity. This provided an important clue to the use of MWCNTs at macroscopic scale. Researchers have made multiple efforts to optimize this aligned structure and improve the properties of MWCNT sheets and fibers. In this Account, we briefly highlight the new synthetic methods and promising applications of aligned MWCNTs for organic optoelectronic materials and devices. We describe several general methods to prepare both horizontally and perpendicularly aligned MWCNT/polymer composite films, through an easy solution or melting process. The composite films exhibit the combined properties of being flexible, transparent, and electrically conductive. These advances may pave the way to new flexible substrates for organic solar cells, sensing devices, and other related applications. Similarly, we discuss the synthesis of aligned MWCNT/polymer composite fibers with interesting mechanical and electrical properties. Through these methods, we can incorporate a wide variety of soluble or fusible polymers for such composite films and fibers. In addition, we can later introduce functional polymers with conjugated backbones or side chains to improve the properties of these composite materials. In particular, cooperative interactions between aligned MWCNTs and polymers can produce novel properties that do not occur individually. Common examples of this are two types of responsive polymers, photodeformable azobenzene-containing liquid crystalline polymer and chromatic polydiacetylene. Aligning the structure of MWCNTs induces the orientation of azobenzene-containing mesogens, and produces photodeformable polymer elastomers. This strategy also solves the long
Analysis of thermodynamic properties for high-temperature superconducting oxides
International Nuclear Information System (INIS)
Kushwah, S.S.; Shanker, J.
1993-01-01
Analysis of thermodynamic properties such as specific heat, Debye temperature, Einstein temperature, thermal expansion coefficient, bulk modulus, and Grueneisen parameter is performed for rare-earth-based, Tl-based, and Bi-based superconducting copper oxides. Values of thermodynamic parameters are calculated and reported. The relationship between the Debye temperature and the superconducting transition temperature is used to estimate the values of T c using the interaction parameters from Ginzburg. (orig.)
Relationship Between Filler-Matrix Interface and Macroscopical Properties of Polymer Nanocomposites
Aguilar Ventura, Isaac Enrique
2017-11-01
The macroscopic properties of Multiwall Carbon Nanotube (MWCNT) polymer nano-composites and multiscale composites have been studied from a multifunctional standpoint. The objective is to understand and correlate the mechanisms in which the addition of a small content of MWCNTs can affect the mechanical, thermal and electrical properties of thermoplastic and thermoset polymer nanocomposites. While CNTs are well-known to possess extraordinary properties in the nanoscale, it has been shown that, the CNT/polymer matrix and CNT/CNT interactions are mainly responsible for the modification of properties in the nanocomposites. Observation of the mechanical properties revealed that the addition of CNTs can increase the stiffness of the material, but the increment of interfacial regions can accelerate the damage process under cyclic loading conditions. Additionally, CNTs can interact with polymer chains in the matrix affecting thermomechanical properties such as the glass transition temperature and the storage modulus. A low content of well-dispersed CNTs can form percolated networks within the matrix, which, due to the nature of the electrical conduction mechanism, have demonstrated potential in increasing the electrical conductivity of the nanocomposites. In contrast, high phonon scattering at the interconnections along the CNT network are responsible for marginal increases in thermal conductivity. In this study, a special focus was placed in modifying the CNT interconnections with a conductive polymer "bridge" to increase the efficiency of the electrical carrier transport. Additional experimental observations such as piezoresistivity and electrical conductivity/temperature dependency, demonstrated the major role of the interfacial regions with respect to the observed material properties in the macroscale. Controlling the interactions that occur in these regions is key to achieve tailorable, multifunctional nanocomposites.
Thermodynamic properties of vitamin B_9
International Nuclear Information System (INIS)
Knyazev, A.V.; Emel’yanenko, V.N.; Shipilova, A.S.; Lelet, M.I.; Gusarova, E.V.; Knyazeva, S.S.; Verevkin, S.P.
2016-01-01
Highlights: • Temperature dependence of heat capacity of vitamin B_9 has been measured by precision adiabatic vacuum calorimetry. • The thermodynamic functions of the vitamin B_9 have been determined for the range from T → 0 to 333 K. • The character of heterodynamics of structure was detected. • Enthalpy of combustion of the vitamin B_9 was measured using high-precision combustion calorimeter. - Abstract: In the present work temperature dependence of heat capacity of vitamin B_9 (folic acid dihydrate) has been measured for the first time in the range from (6 to 333) K by precision adiabatic vacuum calorimetry. Based on the experimental values, the thermodynamic functions of the vitamin B_9, namely, the heat capacity, enthalpy H°(T) − H°(0), entropy S°(T) − S°(0) and Gibbs function G°(T) − H°(0) have been determined for the range from T → (0 to 333) K. The value of the fractal dimension D in the function of multifractal generalization of Debye’s theory of the heat capacity of solids was estimated and the character of heterodynamics of structure was detected. Enthalpy of combustion (−8942.8 ± 7.5) kJ·mol"−"1 of the vitamin B_9 was measured for the first time using a high-precision combustion calorimeter. The standard molar enthalpy of formation in the crystalline state (−1821.0 ± 7.9) kJ·mol"−"1 of B_9 at 298.15 K was derived from the combustion experiments. Using a combination of the adiabatic and combustion calorimetry results, the thermodynamic functions of formation of the folic acid dihydrate at T = 298.15 K and p = 0.1 MPa have been calculated. The low-temperature X-ray diffraction was used for the determination of coefficients of thermal expansion.
Thermodynamic properties of gaseous ruthenium species.
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.
Thermodynamic properties for arsenic minerals and aqueous species
Nordstrom, D. Kirk; Majzlan, Juraj; Königsberger, Erich; Bowell, Robert J.; Alpers, Charles N.; Jamieson, Heather E.; Nordstrom, D. Kirk; Majzlan, Juraj
2014-01-01
Quantitative geochemical calculations are not possible without thermodynamic databases and considerable advances in the quantity and quality of these databases have been made since the early days of Lewis and Randall (1923), Latimer (1952), and Rossini et al. (1952). Oelkers et al. (2009) wrote, “The creation of thermodynamic databases may be one of the greatest advances in the field of geochemistry of the last century.” Thermodynamic data have been used for basic research needs and for a countless variety of applications in hazardous waste management and policy making (Zhu and Anderson 2002; Nordstrom and Archer 2003; Bethke 2008; Oelkers and Schott 2009). The challenge today is to evaluate thermodynamic data for internal consistency, to reach a better consensus of the most reliable properties, to determine the degree of certainty needed for geochemical modeling, and to agree on priorities for further measurements and evaluations.
Thermodynamic and structural properties in complexing media
International Nuclear Information System (INIS)
Di Giandomenico, M.V.
2007-10-01
Protactinium is experiencing a renewal of interest in the frame of long-term energy production. Modelling the behaviour of this element in the geosphere requires thermodynamic and structural data relevant to environmental conditions. Now deep clayey formation are considered for the disposal of radioactive waste and high values of natural sulphate contents have been determined in pore water in equilibrium with clay surface. Because of its tendency to polymerisation, hydrolysis and sorption on all solid supports, the equilibria constants relative to monomer species were determined at tracer scale (ca. 10 - 12 M) with 233 Pa. The complexation constants of Pa(V) and sulphate ions were calculated starting from a systematic study of the apparent distribution coefficient D in the system TTA/Toluene/H 2 O/Na 2 SO 4 /HClO 4 /NaClO 4 and as a function of ionic strength, temperature, free sulphate, protons and chelatant concentration. First of all, the interaction between free species H + , SO 4 - , Na + leads to the formation of HSO 4 - and NaSO 4 - , for which concentrations depend upon the related thermodynamic constants. For this purpose a computer code was developed in order to determine all free species concentration. This iterative code takes into account the influence of temperature and ionic strength (SIT modelling) on thermodynamic constants. The direct measure of Pa(V) in the organic and aqueous phase by g-spectrometry had conducted to estimate the apparent distribution coefficient D as function of free sulphate ions. Complexation constants have been determined after a mathematical treatment of D. The extrapolation of these constants at zero ionic strength have been realized by SIT modelling at different temperatures. Besides, enthalpy and entropy values were calculated. Parallelly, the structural study of Pa(V) was performed using 231 Pa. XANES and EXAFS spectra show unambiguously the absence of the trans di-oxo bond that characterizes the other early actinide
Thermodynamical properties of liquid lanthanides-A variational approach
Energy Technology Data Exchange (ETDEWEB)
Patel, H. P. [Department of Physics, Veer Narmad South Gujarat University, Surat 395 007, Gujarat (India); Department of Applied Physics, S. V. National Institute of Technology, Surat 395 007, Gujarat (India); Thakor, P. B., E-mail: pbthakor@rediffmail.com [Department of Physics, Veer Narmad South Gujarat University, Surat 395 007, Gujarat (India); Sonvane, Y. A. [Department of Applied Physics, S. V. National Institute of Technology, Surat 395 007, Gujarat (India)
2015-06-24
Thermodynamical properties like Entropy (S), Internal energy (E) and Helmholtz free energy (F) of liquid lanthanides using a variation principle based on the Gibbs-Bogoliubuv (GB) inequality with Percus Yevick hard sphere reference system have been reported in the present investigation. To describe electron-ion interaction we have used our newly constructed parameter free model potential along with Sarkar et al. local field correction function. Lastly, we conclude that our newly constructed model potential is capable to explain the thermodynamical properties of liquid lanthanides.
Langevin dynamics encapsulate the microscopic and emergent macroscopic properties of midge swarms
2018-01-01
In contrast to bird flocks, fish schools and animal herds, midge swarms maintain cohesion but do not possess global order. High-speed imaging techniques are now revealing that these swarms have surprising properties. Here, I show that simple models found on the Langevin equation are consistent with this wealth of recent observations. The models predict correctly that large accelerations, exceeding 10 g, will be common and they predict correctly the coexistence of core condensed phases surrounded by dilute vapour phases. The models also provide new insights into the influence of environmental conditions on swarm dynamics. They predict that correlations between midges increase the strength of the effective force binding the swarm together. This may explain why such correlations are absent in laboratory swarms but present in natural swarms which contend with the wind and other disturbances. Finally, the models predict that swarms have fluid-like macroscopic mechanical properties and will slosh rather than slide back and forth after being abruptly displaced. This prediction offers a promising avenue for future experimentation that goes beyond current quasi-static testing which has revealed solid-like responses. PMID:29298958
Thermodynamic properties of alkali borosilicate gasses and metaborates
International Nuclear Information System (INIS)
Asano, Mitsuru
1992-01-01
Borosilicate glasses are the proposed solidifying material for storing high level radioactive wastes in deep underground strata. Those have low melting point, and can contain relatively large amount of high level radioactive wastes. When borosilicate glasses are used for this purpose, they must be sufficiently stable and highly reliable in the vitrification process, engineered storage and the disposal in deep underground strata. The main vaporizing components from borosilicate glasses are alkali elements and boron. In this report, as for the vaporizing behavior of alkali borosilicate glasses, the research on thermodynamic standpoint carried out by the authors is explained, and the thermodynamic properties of alkali metaborates of monomer and dimer which are the main evaporation gases are reported. The evaporation and the activity of alkali borosilicate glasses, the thermodynamic properties of alkali borosilicate glasses, gaseous alkali metaborates and alkali metaborate system solid solution and so on are described. (K.I.)
Entropy, related thermodynamic properties, and structure of methylisocyanate
International Nuclear Information System (INIS)
Davis, Phil S.; Kilpatrick, John E.
2013-01-01
Highlights: ► The thermodynamic properties of methylisocyanate have been determined by isothermal calorimetry from 15 to 298.15 K. ► The third law entropy has been compared with the entropy calculated by statistical thermodynamics. ► The comparisons are consistent with selected proposed molecular structures and vibrational frequencies. -- Abstract: The entropy and related thermodynamic properties of methylisocyanate, CH 3 NCO, have been determined by isothermal calorimetry. The entropy in the ideal gas state at 298.15 K and 1 atmosphere is S m o = 284.3 ± 0.6 J/K · mol. Other thermodynamic properties determined include: the heat capacity from 15 to 300 K, the temperature of fusion (T fus = 178.461 ± 0.024 K), the enthalpy of fusion (ΔH fus = 7455.2 ± 14.0 J/mol), the enthalpy of vaporization at 298.15 K (ΔH vap = 28768 ± 54 J/mol), and the vapor pressure from fusion to 300 K. Using statistical thermodynamics, the entropy in this same state has been calculated for various assumed structures for methylisocyante which have been proposed based on several spectroscopic and ab initio results. Comparisons between the experimental and calculated entropy have led to the following conclusions concerning historical differences among problematic structural properties: (1) The CNC/CNO angles can have the paired values of 140/180° or 135/173° respectively. It is not possible to distinguish between the two by this thermodynamic analysis. (2) The methyl group functions as a free rotor or near free rotor against the NCO rigid frame. The barrier to internal rotation is less than 2100 J/mol. (3) The CNC vibrational bending frequency is consistent with the more recently observed assignments at 165 and 172 cm −1 with some degree of anharmonicity or with a pure harmonic at about 158 cm −1
Prediction of thermodynamic properties of coal derivatives
International Nuclear Information System (INIS)
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
Thermodynamic properties of bulk and confined water
Energy Technology Data Exchange (ETDEWEB)
Mallamace, Francesco, E-mail: francesco.mallamace@unime.it [Dipartimento di Fisica e Scienza della Terra Università di Messina and CNISM, I-98168 Messina (Italy); Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Center for Polymer Studies and Department of Physics, Boston University, Boston, Massachusetts 02215 (United States); Corsaro, Carmelo [Dipartimento di Fisica e Scienza della Terra Università di Messina and CNISM, I-98168 Messina (Italy); Mallamace, Domenico [Dipartimento di Scienze dell' Ambiente, della Sicurezza, del Territorio, degli Alimenti e della Salute, Università di Messina, I-98166 Messina (Italy); Vasi, Sebastiano; Vasi, Cirino [IPCF-CNR, I-98166 Messina (Italy); Stanley, H. Eugene [Center for Polymer Studies and Department of Physics, Boston University, Boston, Massachusetts 02215 (United States)
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 α{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 *})
Thermodynamical quantum information sharing
International Nuclear Information System (INIS)
Wiesniak, M.; Vedral, V.; Brukner, C.
2005-01-01
Full text: Thermodynamical properties fully originate from classical physics and can be easily measured for macroscopic systems. On the other hand, entanglement is a widely spoken feature of quantum physics, which allows to perform certain task with efficiency unavailable with any classical resource. Therefore an interesting question is whether we can witness entanglement in a state of a macroscopic sample. We show, that some macroscopic properties, in particular magnetic susceptibility, can serve as an entanglement witnesses. We also study a mutual relation between magnetic susceptibility and magnetisation. Such a complementarity exhibits quantum information sharing between these two thermodynamical quantities. Magnetization expresses properties of individual spins, while susceptibility might reveal non-classical correlations as a witness. Therefore, a rapid change of one of these two quantities may mean a phase transition also in terms of entanglement. The complementarity relation is demonstrated by an analytical solution of an exemplary model. (author)
On lumped models for thermodynamic properties of simulated annealing problems
International Nuclear Information System (INIS)
Andresen, B.; Pedersen, J.M.; Salamon, P.; Hoffmann, K.H.; Mosegaard, K.; Nulton, J.
1987-01-01
The paper describes a new method for the estimation of thermodynamic properties for simulated annealing problems using data obtained during a simulated annealing run. The method works by estimating energy-to-energy transition probabilities and is well adapted to simulations such as simulated annealing, in which the system is never in equilibrium. (orig.)
Computer program for calculating thermodynamic and transport properties of fluids
Hendricks, R. C.; Braon, A. K.; Peller, I. C.
1975-01-01
Computer code has been developed to provide thermodynamic and transport properties of liquid argon, carbon dioxide, carbon monoxide, fluorine, helium, methane, neon, nitrogen, oxygen, and parahydrogen. Equation of state and transport coefficients are updated and other fluids added as new material becomes available.
Review and recommended thermodynamic properties of FeCO3
DEFF Research Database (Denmark)
Fosbøl, Philip Loldrup; Thomsen, Kaj; Stenby, Erling Halfdan
2010-01-01
An extensive review of entropy, enthalpy of formation and Gibbs energy of formation, heat capacity, aqueous solubility and solubility constant of FeCO3 is given. A consistent set of thermodynamic properties for FeCO3 and relevant aqeous species is selected and recommended for use. Speciation...
Thermodynamic Properties of a Trapped Interacting Bose Gas
Shi, Hualin; Zheng, Wei-Mou
1996-01-01
A Bose gas in an external potential is studied by means of the local density approximation. Analytical results are derived for the thermodynamic properties of an ideal Bose gas in a generic power-law trapping potential, and their dependence on the mutual interaction of atoms in the case of a non-ideal Bose gas.
Microcomputer Calculation of Thermodynamic Properties from Molecular Parameters of Gases.
Venugopalan, Mundiyath
1990-01-01
Described in this article is a problem-solving activity which integrates the application of microcomputers with the learning of physical chemistry. Students use the program with spectroscopic data to calculate the thermodynamic properties and compare them with the values from the thermochemical tables. (Author/KR)
Structure and thermodynamic properties of molten rubidium chloride
International Nuclear Information System (INIS)
Ballone, P.; Pastore, G.; Tosi, M.P.; Trieste Univ.
1984-02-01
Self-consistent calculations of partial pair distribution functions and thermodynamic properties are presented for molten RbCl in a non-polarizable-ion model and compared with computer simulation data. The theory, which is quantitatively very successful, hinges on an empirical evaluation of bridge diagrams including both excluded-volume effects and long-range Coulomb effects. (author)
High-temperature of thermodynamic properties of sodium
Energy Technology Data Exchange (ETDEWEB)
Padilla, A. Jr.
1977-01-01
The set of high-temperature thermodynamic properties for sodium in the two-phase and subcooled-liquid regions which was previously recommended, has been modified to incorporate recent experimental data. In particular, replacement of the previously estimated critical constants with experimentally-determined values has resulted in substantial differences in the region of the critical point. The following thermodynamic properties were determined: pressure, density, enthalpy, entropy, internal energy, compressibility (adiabatic and isothermal), thermal expansion coefficient, thermal pressure coefficient, and specific heat (constant-pressure and constant-volume). These properties were determined for the saturated liquid, saturated vapor, subcooled liquid, and superheated vapor. The superheated vapor properties are limited to low pressures and more work is required to extend them to higher pressures. The supercritical region was not investigated.
International Nuclear Information System (INIS)
Xiao, Tiejun
2015-01-01
In this paper, the longitudinal dielectric function ϵ_l(k) of primitive electrolyte solutions is discussed. Starting from a modified mean spherical approximation, an analytical dielectric function in terms of two parameters is established. These two parameters can be related to the first two decay parameters k_1_,_2 of the dielectric response modes of the bulk system, and can be determined using constraints of k_1_,_2 from statistical theories. Furthermore, a combination of this dielectric function and the molecular Debye-Hückel theory[J. Chem. Phys. 135(2011)104104] leads to a self-consistent mean filed description of electrolyte solutions. Our theory reveals a relationship between the microscopic structure parameters of electrolyte solutions and the macroscopic thermodynamic properties, which is applied to concentrated electrolyte solutions.
Macroscopic anisotropic bone material properties in children with severe osteogenesis imperfecta.
Albert, Carolyne; Jameson, John; Tarima, Sergey; Smith, Peter; Harris, Gerald
2017-11-07
Children with severe osteogenesis imperfecta (OI) typically experience numerous fractures and progressive skeletal deformities over their lifetime. Recent studies proposed finite element models to assess fracture risk and guide clinicians in determining appropriate intervention in children with OI, but lack of appropriate material property inputs remains a challenge. This study aimed to characterize macroscopic anisotropic cortical bone material properties and investigate relationships with bone density measures in children with severe OI. Specimens were obtained from tibial or femoral shafts of nine children with severe OI and five controls. The specimens were cut into beams, characterized in bending, and imaged by synchrotron radiation X-ray micro-computed tomography. Longitudinal modulus of elasticity, yield strength, and bending strength were 32-65% lower in the OI group (p<0.001). Yield strain did not differ between groups (p≥0.197). In both groups, modulus and strength were lower in the transverse direction (p≤0.009), but anisotropy was less pronounced in the OI group. Intracortical vascular porosity was almost six times higher in the OI group (p<0.001), but no differences were observed in osteocyte lacunar porosity between the groups (p=0.086). Volumetric bone mineral density was lower in the OI group (p<0.001), but volumetric tissue mineral density was not (p=0.770). Longitudinal OI bone modulus and strength were correlated with volumetric bone mineral density (p≤0.024) but not volumetric tissue mineral density (p≥0.099). Results indicate that cortical bone in children with severe OI yields at the same strain as normal bone, and that their decreased bone material strength is associated with reduced volumetric bone mineral density. These results will enable the advancement of fracture risk assessment capability in children with severe OI. Copyright © 2017 Elsevier Ltd. All rights reserved.
Zhou, S.; Solana, J. R.
2018-03-01
Monte Carlo NVT simulations have been performed to obtain the thermodynamic and structural properties and perturbation coefficients up to third order in the inverse temperature expansion of the Helmholtz free energy of fluids with potential models proposed in the literature for diamond and wurtzite lattices. These data are used to analyze performance of a coupling parameter series expansion (CPSE). The main findings are summarized as follows, (1) The CPSE provides accurate predictions of the first three coefficient in the inverse temperature expansion of Helmholtz free energy for the potential models considered and the thermodynamic properties of these fluids are predicted more accurately when the CPSE is truncated at second or third order. (2) The Barker-Henderson (BH) recipe is appropriate for determining the effective hard sphere diameter for strongly repulsive potential cores, but its performance worsens with increasing the softness of the potential core. (3) For some thermodynamic properties the first-order CPSE works better for the diamond potential, whose tail is dominated by repulsive interactions, than for the potential, whose tail is dominated by attractive interactions. However, the first-order CPSE provides unsatisfactory results for the excess internal energy and constant-volume excess heat capacity for the two potential models.
Ben-Naim, Arieh
2017-01-01
This textbook introduces thermodynamics with a modern approach, starting from four fundamental physical facts (the atomic nature of matter, the indistinguishability of atoms and molecules of the same species, the uncertainty principle, and the existence of equilibrium states) and analyzing the behavior of complex systems with the tools of information theory, in particular with Shannon's measure of information (or SMI), which can be defined on any probability distribution. SMI is defined and its properties and time evolution are illustrated, and it is shown that the entropy is a particular type of SMI, i.e. the SMI related to the phase-space distribution for a macroscopic system at equilibrium. The connection to SMI allows the reader to understand what entropy is and why isolated systems follow the Second Law of Thermodynamics. The Second Llaw is also formulated for other systems, not thermally isolated and even open with respect to the transfer of particles. All the fundamental aspects of thermodynamics are d...
Thermodynamic properties of a liquid crystal carbosilane dendrimer
Samosudova, Ya. S.; Markin, A. V.; Smirnova, N. N.; Ogurtsov, T. G.; Boiko, N. I.; Shibaev, V. P.
2016-11-01
The temperature dependence of the heat capacity of a first-generation liquid crystal carbosilane dendrimer with methoxyphenyl benzoate end groups is studied for the first time in the region of 6-370 K by means of precision adiabatic vacuum calorimetry. Physical transformations are observed in this interval of temperatures, and their standard thermodynamic characteristics are determined and discussed. Standard thermodynamic functions C p ° ( T), H°( T) - H°(0), S°( T) - S°(0), and G°( T) - H°(0) are calculated from the obtained experimental data for the region of T → 0 to 370 K. The standard entropy of formation of the dendrimer in the partially crystalline state at T = 298.15 K is calculated, and the standard entropy of the hypothetic reaction of its synthesis at this temperature is estimated. The thermodynamic properties of the studied dendrimer are compared to those of second- and fourth-generation liquid crystal carbosilane dendrimers with the same end groups studied earlier.
Cheng, Penghui
2016-07-01
Fuel mixture formation and spray characteristics are crucial for the advancement of Gasoline Compression Ignition (GCI) engine. For investigations of spray characteristics, a high-pressure high-temperature spray chamber with constant volume has been designed, tested and commissioned at CCRC, KAUST. Back light illumination technique has been applied to investigate the macroscopic spray properties of an outwardly opening piezoelec- tric injector. Three parameters including injection pressure, ambient pressure, and ambient temperature have been involved. A total of 18 combinations of experimental conditions were tested under non-reactive conditions. Through qualitative analysis of spray morphology under different operating conditions, an apparent distinction of spray morphology has been noticed. Spray morphology and propagation have shown strong dependencies on ambient pressure and ambient tempera- ture while injection pressure has a negligible effect on spray shape. Increasingly compact and bushier spray patterns were observed in the cases of high ambient pressure due to in- creasing aerodynamic drag force on spray boundary. It should also be noted that ambient temperature plays a fairly important role in fuel evaporation rate. At 200 °C, oscillating and considerably short spray shape was produced. Also, circumferential ring-like vortices and distinctive string-like structures have been identified for the fuel spray exiting this hollow cone injector. It has been observed that high ambient pressure conditions (Pamb = 4 bar and 10.5 bar) are favorable to the vortices generation, which has also been reported in previous literature. The quantitative description of macroscopic spray properties reveals that ambient pres- sure and ambient temperature are found to be the most influential parameters on liquid penetration length. The rise of ambient pressure results in considerably shorter liquid pen- etration length. Ambient temperature also appears to be a very effective
Experimental approaches to membrane thermodynamics
DEFF Research Database (Denmark)
Westh, Peter
2009-01-01
Thermodynamics describes a system on the macroscopic scale, yet it is becoming an important tool for the elucidation of many specific molecular aspects of membrane properties. In this note we discuss this application of thermodynamics, and give a number of examples on how thermodynamic measurements...... have contributed to the understanding of specific membrane phenomena. We mainly focus on non-specific interactions of bilayers and small molecules (water and solutes) in the surrounding solvent, and the changes in membrane properties they bring about. Differences between thermodynamic...
Industrial Requirements for Thermodynamics and Transport Properties
DEFF Research Database (Denmark)
Hendriks, Eric; Kontogeorgis, Georgios; Dohrn, Ralf
2010-01-01
the direction for future development. The use of new methods, such as SAFT, is increasing, but they are not yet in position to replace traditional methods such as cubic equations of state (especially in oil and gas industry) and the UNIFAC group contribution approach. A common problem with novel methods is lack...... addressed to or written by industrial colleagues, are discussed initially. This provides the context of the survey and material with which the results of the survey can be compared. The results of the survey have been divided into the themes: data, models, systems, properties, education, and collaboration...... of standardization, reference data, and correct and transparent implementations, especially in commercially available simulation programs. The survey indicates a great variety of systems where further work is required. For instance, for electrolyte systems better models are needed, capable of describing all types...
Thermodynamic properties of an emerging chemical disinfectant, peracetic acid.
Zhang, Chiqian; Brown, Pamela J B; Hu, Zhiqiang
2018-04-15
Peracetic acid (PAA or CH 3 COOOH) is an emerging disinfectant with a low potential to form carcinogenic disinfection by-products (DBPs). Basic thermodynamic properties of PAA are, however, absent or inconsistently reported in the literature. This review aimed to summarize important thermodynamic properties of PAA, including standard Gibbs energy of formation and oxidation-reduction (redox) potential. The standard Gibbs energies of formation of CH 3 COOOH (aq) , CH 3 COOOH (g) , CH 3 COOOH (l) , and CH 3 COOO (aq) - are -299.41kJ·mol -1 , -283.02kJ·mol -1 , -276.10kJ·mol -1 , and -252.60kJ·mol -1 , respectively. The standard redox potentials of PAA are 1.748V and 1.005V vs. standard hydrogen electrode (SHE) at pH 0 and pH 14, respectively. Under biochemical standard state conditions (pH 7, 25°C, 101,325Pa), PAA has a redox potential of 1.385V vs. SHE, higher than many disinfectants. Finally, the environmental implications of the thermodynamic properties of PAA were systematically discussed. Those properties can be used to predict the physicochemical and biological behavior of aquatic systems exposed to PAA. Copyright © 2017 Elsevier B.V. All rights reserved.
Tables of thermodynamic properties of helium magnet coolant
International Nuclear Information System (INIS)
McAshan, M.
1992-07-01
The most complete treatment of the thermodynamic properties of helium at the present time is the monograph by McCarty: ''Thermodynamic Properties of Helium 4 from 2 to 1500 K at Pressures to 10 8 Pa'', Robert D. McCarty, Journal of Physical and Chemical Reference Data, Vol. 2, page 923--1040 (1973). In this work the complete range of data on helium is examined and the P-V-T surface is described by an equation of state consisting of three functions P(r,T) covering different regions together with rules for making the transition from one region to another. From this thermodynamic compilation together with correlations of the transport properties of helium was published the well-known NBS Technical Note: ''Thermophysical Properties of Helium 4 from 2 to 1500 K with pressures to 1000 Atmospheres'', Robert D. McCarty, US Department of Commerce, National Bureau of Standards Technical Note 631 (1972). This is the standard reference for helium cryogenics. The NBS 631 tables cover a wide range of temperature and pressure, and as a consequence, the number of points tabulated in the region of the single phase coolant for the SSC magnets are relatively few. The present work sets out to cover the range of interest in more detail in a way that is consistent with NBS 631. This new table is essentially identical to the older one and can be used as an auxiliary to it
Thermodynamic properties of fluids from Fluctuation Solution Theory
International Nuclear Information System (INIS)
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
Fernandes, M Marques; Scheinost, A C; Baeyens, B
2016-08-01
or two carbonate groups pointing away from the surface into the solution phase. Within the spectroscopically observable concentration range these complexes could only be identified on the weak sites, in line with the small strong site capacity suggested by the refined sorption model. When the solubility of carbonates was exceeded, formation of an Am carbonate hydroxide could be identified. The excellent agreement between the thermodynamic model parameters obtained by fitting the macroscopic data, and the spectroscopically identified mechanisms, demonstrates the mature state of the 2SPNE SC/CE model for predicting and quantifying the retention of Ln/An(III) elements by montmorillonite-rich clay rocks. Copyright © 2016 Elsevier Ltd. All rights reserved.
Prediction of thermodynamic properties of refrigerants using data mining
International Nuclear Information System (INIS)
Kuecueksille, Ecir Ugur; Selbas, Resat; Sencan, Arzu
2011-01-01
The analysis of vapor compression refrigeration systems requires the availability of simple and efficient mathematical formulations for the determination of thermodynamic properties of refrigerants. The aim of this study is to determine thermodynamic properties as enthalpy, entropy and specific volume of alternative refrigerants using data mining method. Alternative refrigerants used in the study are R134a, R404a, R407c and R410a. The results obtained from data mining have been compared to actual data from the literature. The study shows that the data mining methodology is successfully applicable to determine enthalpy, entropy and specific volume values for any temperature and pressure of refrigerants. Therefore, computation time reduces and simulation of vapor compression refrigeration systems is fairly facilitated.
Magnetic properties and thermodynamics in a metallic nanotube
International Nuclear Information System (INIS)
Jiang, Wei; Li, Xiao-Xi; Guo, An-Bang; Guan, Hong-Yu; Wang, Zan; Wang, Kai
2014-01-01
A metallic nanotube composed of the ferromagnetic spin-3/2 inner shell and spin-1 outer shell with a ferrimagnetic interlayer coupling has been studied by using the effective-field theory with correlations (EFT). With both existence of the magnetic anisotropy and transverse field, we have studied effects of them on the magnetic properties and the thermodynamics. Some interesting phenomena have been found in the phase diagrams. At low temperature, the magnetization curves present different behaviors. Two compensation points have been found for the certain values of the system parameters in the system. The research results of metallic nanotubes may have potential applications in the fields of biomedicine and molecular devices. - Highlights: • A hexagonal metallic nanotube is composed of spin-3/2 inner layer and spin-1 outer layer. • Various types of magnetization curves depend on physical parameters and temperature. • We study the effects of physical parameters on the magnetic properties and thermodynamics
Fermi, Enrico
1956-01-01
Indisputably, this is a modern classic of science. Based on a course of lectures delivered by the author at Columbia University, the text is elementary in treatment and remarkable for its clarity and organization. Although it is assumed that the reader is familiar with the fundamental facts of thermometry and calorimetry, no advanced mathematics beyond calculus is assumed.Partial contents: thermodynamic systems, the first law of thermodynamics (application, adiabatic transformations), the second law of thermodynamics (Carnot cycle, absolute thermodynamic temperature, thermal engines), the entr
A thermodynamic approach to obtain materials properties for engineering applications
Chang, Y. Austin
1993-01-01
With the ever increases in the capabilities of computers for numerical computations, we are on the verge of using these tools to model manufacturing processes for improving the efficiency of these processes as well as the quality of the products. One such process is casting for the production of metals. However, in order to model metal casting processes in a meaningful way it is essential to have the basic properties of these materials in their molten state, solid state as well as in the mixed state of solid and liquid. Some of the properties needed may be considered as intrinsic such as the density, heat capacity or enthalpy of freezing of a pure metal, while others are not. For instance, the enthalpy of solidification of an alloy is not a defined thermodynamic quantity. Its value depends on the micro-segregation of the phases during the course of solidification. The objective of the present study is to present a thermodynamic approach to obtain some of the intrinsic properties and combining thermodynamics with kinetic models to estimate such quantities as the enthalpy of solidification of an alloy.
Macroscopic theory of superconductors
International Nuclear Information System (INIS)
Carr, W.J. Jr.
1981-01-01
A macroscopic theory for bulk superconductors is developed in the framework of the theory for other magnetic materials, where ''magnetization'' current is separated from ''free'' current on the basis of scale. This contrasts with the usual separation into equilibrium and nonequilibrium currents. In the present approach magnetization, on a large macroscopic scale, results from the vortex current, while the Meissner current and other surface currents are surface contributions to the Maxwell j. The results are important for the development of thermodynamics in type-II superconductors. The advantage of the description developed here is that magnetization becomes a local concept and its associated magnetic field can be given physical meaning
Predicting structural properties of fluids by thermodynamic extrapolation
Mahynski, Nathan A.; Jiao, Sally; Hatch, Harold W.; Blanco, Marco A.; Shen, Vincent K.
2018-05-01
We describe a methodology for extrapolating the structural properties of multicomponent fluids from one thermodynamic state to another. These properties generally include features of a system that may be computed from an individual configuration such as radial distribution functions, cluster size distributions, or a polymer's radius of gyration. This approach is based on the principle of using fluctuations in a system's extensive thermodynamic variables, such as energy, to construct an appropriate Taylor series expansion for these structural properties in terms of intensive conjugate variables, such as temperature. Thus, one may extrapolate these properties from one state to another when the series is truncated to some finite order. We demonstrate this extrapolation for simple and coarse-grained fluids in both the canonical and grand canonical ensembles, in terms of both temperatures and the chemical potentials of different components. The results show that this method is able to reasonably approximate structural properties of such fluids over a broad range of conditions. Consequently, this methodology may be employed to increase the computational efficiency of molecular simulations used to measure the structural properties of certain fluid systems, especially those used in high-throughput or data-driven investigations.
Thermodynamic properties of indan: Experimental and computational results
International Nuclear Information System (INIS)
Chirico, Robert D.; Steele, William V.; Kazakov, Andrei F.
2016-01-01
Highlights: • Heat capacities were measured for the temperature range (5 to 445) K. • Vapor pressures were measured for the temperature range (338 to 495) K. • Densities at saturation pressure were measured from T = (323 to 523) K. • Computed and experimentally derived properties for ideal gas entropies are in excellent accord. • Thermodynamic consistency analysis revealed anomalous literature data. - Abstract: Measurements leading to the calculation of thermodynamic properties in the ideal-gas state for indan (Chemical Abstracts registry number [496-11-7], 2,3-dihydro-1H-indene) are reported. Experimental methods were adiabatic heat-capacity calorimetry, differential scanning calorimetry, comparative ebulliometry, and vibrating-tube densitometry. Molar thermodynamic functions (enthalpies, entropies, and Gibbs energies) for the condensed and ideal-gas states were derived from the experimental studies at selected temperatures. Statistical calculations were performed based on molecular geometry optimization and vibrational frequencies calculated at the B3LYP/6-31+G(d, p) level of theory. Computed ideal-gas properties derived with the rigid-rotor harmonic-oscillator approximation are shown to be in excellent accord with ideal-gas entropies derived from thermophysical property measurements of this research, as well as with experimental heat capacities for the ideal-gas state reported in the literature. Literature spectroscopic studies and ab initio calculations report a range of values for the barrier to ring puckering. Results of the present work are consistent with a large barrier that allows use of the rigid-rotor harmonic-oscillator approximation for ideal-gas entropy and heat-capacity calculations, even with the stringent uncertainty requirements imposed by the calorimetric and physical property measurements reported here. All experimental results are compared with property values reported in the literature.
A Systematic Identification Method for Thermodynamic Property Modelling
DEFF Research Database (Denmark)
Ana Perederic, Olivia; Cunico, Larissa; Sarup, Bent
2017-01-01
In this work, a systematic identification method for thermodynamic property modelling is proposed. The aim of the method is to improve the quality of phase equilibria prediction by group contribution based property prediction models. The method is applied to lipid systems where the Original UNIFAC...... model is used. Using the proposed method for estimating the interaction parameters using only VLE data, a better phase equilibria prediction for both VLE and SLE was obtained. The results were validated and compared with the original model performance...
Mixed 2D molecular systems: Mechanic, thermodynamic and dielectric properties
Energy Technology Data Exchange (ETDEWEB)
Beno, Juraj [Department of Physics, Faculty of Electrical Engineering and Information Technology, Slovak University of Technology, Ilkovicova 3, 812 19-SK Bratislava (Slovakia); Weis, Martin [Department of Physics, Faculty of Electrical Engineering and Information Technology, Slovak University of Technology, Ilkovicova 3, 812 19-SK Bratislava (Slovakia)], E-mail: Martin.Weis@stuba.sk; Dobrocka, Edmund [Department of Physics, Faculty of Electrical Engineering and Information Technology, Slovak University of Technology, Ilkovicova 3, 812 19-SK Bratislava (Slovakia); Institute of Electrical Engineering, Slovak Academy of Sciences, Dubravska cesta 9, 841 04-SK Bratislava (Slovakia); Hasko, Daniel [International Laser Centre, Ilkovicova 3, 812 19-SK Bratislava (Slovakia)
2008-08-15
Study of Langmuir monolayers consisting of stearic acid (SA) and dipalmitoylphosphatidylcholine (DPPC) molecules was done by surface pressure-area isotherms ({pi}-A), the Maxwell displacement current (MDC) measurement, X-ray reflectivity (XRR) and atomic force microscopy (AFM) to investigate the selected mechanic, thermodynamic and dielectric properties based on orientational structure of monolayers. On the base of {pi}-A isotherms analysis we explain the creation of stable structures and found optimal monolayer composition. The dielectric properties represented by MDC generated monolayers were analyzed in terms of excess dipole moment, proposing the effect of dipole-dipole interaction. XRR and AFM results illustrate deposited film structure and molecular ordering.
Calculation of thermodynamic properties of multicomponent ionic reciprocal systems
International Nuclear Information System (INIS)
Saboungi, M.
1980-01-01
Thermodynamic properties of multicomponent ionic reciprocal systems are derived using the conformal ionic solution theory. The equations obtained are more general than previous equations and depend solely on the properties of the components and on those of the binary subsystems. The behavior of dilute solutions is carefully studied leading to a priori predictions of solubility products in multicomponent systems. The solubility products and the specific bond free energy for making an ion pair, e.g., the pair (A--X) in the binary solvent BY--CY, are shown to depend upon specific ionic interactions in the binary subsystems. The equations presented are compared with equations derived from prior theories
Directory of Open Access Journals (Sweden)
Dunya Mahammad Babanly
2017-01-01
Full Text Available The solid-phase diagram of the Tl-TlBr-S system was clarified and the fundamental thermodynamic properties of Tl6SBr4 compound were studied on the basis of electromotive force (EMF measurements of concentration cells relative to a thallium electrode. The EMF results were used to calculate the relative partial thermodynamic functions of thallium in alloys and the standard integral thermodynamic functions (-ΔfG0, -ΔfH0, and S0298 of Tl6SBr4 compound. All data regarding thermodynamic properties of thallium chalcogen-halides are generalized and comparatively analyzed. Consequently, certain regularities between thermodynamic functions of thallium chalcogen-halides and their binary constituents as well as degree of ionization (DI of chemical bonding were revealed.
Thermodynamic properties of magnetic strings on a square lattice
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.
The VLab repository of thermodynamics and thermoelastic properties of minerals
Da Silveira, P. R.; Sarkar, K.; Wentzcovitch, R. M.; Shukla, G.; Lindemann, W.; Wu, Z.
2015-12-01
Thermodynamics and thermoelastic properties of minerals at planetary interior conditions are essential as input for geodynamics simulations and for interpretation of seismic tomography models. Precise experimental determination of these properties at such extreme conditions is very challenging. Therefore, ab initio calculations play an essential role in this context, but at the cost of great computational effort and memory use. Setting up a widely accessible and versatile mineral physics database can relax unnecessary repetition of such computationally intensive calculations. Access to such data facilitates transactional interaction across fields and can advance more quickly insights about deep Earth processes. Hosted by the Minnesota Supercomputing Institute, the Virtual Laboratory for Earth and Planetary Materials (VLab) was designed to develop and promote the theory of planetary materials using distributed, high-throughput quantum calculations. VLab hosts an interactive database of thermodynamics and thermoelastic properties or minerals computed by ab initio. Such properties can be obtained according to user's preference. The database is accompanied by interactive visualization tools, allowing users to repeat and build upon previously published results. Using VLab2015, we have evaluated thermoelastic properties, such as elastic coefficients (Cij), Voigt, Reuss, and Voigt-Reuss-Hill aggregate averages for bulk (K) and shear modulus (G), shear wave velocity (VS), longitudinal wave velocity (Vp), and bulk sound velocity (V0) for several important minerals. Developed web services are general and can be used for crystals of any symmetry. Results can be tabulated, plotted, or downloaded from the VLab website according to user's preference.
Thermodynamic properties of solid deuterium in premelting region
International Nuclear Information System (INIS)
Udovichenko, B.G.; Esel'son, V.B.; Manzhelij, V.G.
1984-01-01
Thermal expansion and isothermal compressibility of solid normal deuterium are measured near the melting line under pressures up to 500 atm. The earlier measurement method is improved to operate in a wider range of working pressures. The effects are discussed which are produced by zero trranslational oscillations in the thermodynamic properties of deuterium. The change in the molar volume in the range from T=0 to the melting temperature is considered as a quantum characteristic of the crystal. The molar volumes of solid deuterium observed at the melting line at moderate P are compared and specified. At P=O and T=0 the molar volume of o-D 2 is found to be V 00 =(20.03+-0.07) cm 3 /mole which follows from the thermodynamic experiment
International Nuclear Information System (INIS)
Prieur, D.
2011-01-01
Fuel irradiation in pressurized water reactors lead to the formation of fission products and minor actinides (Np, Am, Cm) which can be transmuted in fast neutrons reactors. In this context, the aim of this work was to study the fabrication conditions of the U 1-y Am y O 2+x fuels which exhibit particular thermodynamical properties requiring an accurate monitoring of the oxygen potential during the sintering step. For this reason, a thermodynamical model was developed to assess the optimum sintering conditions for these materials. From these calculations, U 1-y Am y O 2+x (y=0.10; 0.15; 0.20; 0.30) were sintered in two range of atmosphere. In hyper-stoichiometric conditions at low temperature, porous and multiphasic compounds are obtained whereas in reducing conditions at high temperature materials are dense and monophasic. XAFS analyses were performed in order to obtain additional experimental data for the thermodynamical modeling refinement. These characterizations also showed the reduction of Am(+IV) to Am(+III) and the partial oxidation of U(+IV) to U(+V) due to a charge compensation mechanism occurring during the sintering. Finally, taking into account the high - activity of Am, self-irradiation effects were studied for two types of microstructures and two Am contents (10 and 15%). For each composition, a lattice parameter increase was observed without structural change coupled with a macroscopic swelling of the pellet diameter up to 1.2% for the dense compounds and 0.6% for the tailored porosity materials. (author) [fr
Thermodynamic properties of water in the critical region
International Nuclear Information System (INIS)
Veloso, Marcelo A.
2009-01-01
The supercritical-water-cooled reactor (SCWR) is one of the nuclear reactor technologies selected for research and development under the Generation IV program. SCWRs offer the potential for high thermal efficiencies and considerable plant simplifications for improved economics. One of the main characteristics of critical water is the strong variations of its thermal-physical properties in the vicinity of the critical point. These large variations may result in an unusual heat transfer behavior. The 1967 IFC Formulation for Industrial Use, which until 1998 formed the basis of steam tables used in many areas of steam power industry throughout the world since the late 1960's, has been now replaced with the IAPWS IF-97 Formulation for the Thermodynamic Properties of Water and Steam for Industrial Use, adopted by the International Association for the Properties of Water and Steam (IAPWS) in 1997. An IAPWS release points out that this new formulation has some unsatisfactory features in the immediate vicinity of the critical point. In order to investigate this singular aspect, which is crucial to better understand the heat transfer mechanism in a SCWR system, predictions by the IAPWS-IF97 formulation will be compared with thermodynamic properties values predicted by an alternative crossover equation of state as well as with experimental data found in literature. (author)
Ben-Naim, Arieh
1987-01-01
This book deals with a subject that has been studied since the beginning of physical chemistry. Despite the thousands of articles and scores of books devoted to solvation thermodynamics, I feel that some fundamen tal and well-established concepts underlying the traditional approach to this subject are not satisfactory and need revision. The main reason for this need is that solvation thermodynamics has traditionally been treated in the context of classical (macroscopic) ther modynamics alone. However, solvation is inherently a molecular pro cess, dependent upon local rather than macroscopic properties of the system. Therefore, the starting point should be based on statistical mechanical methods. For many years it has been believed that certain thermodynamic quantities, such as the standard free energy (or enthalpy or entropy) of solution, may be used as measures of the corresponding functions of solvation of a given solute in a given solvent. I first challenged this notion in a paper published in 1978 b...
Chemical and Thermodynamic Properties at High Temperatures: A Symposium
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.
Thermodynamic properties of 5-(1-adamantyl)tetrazole
Energy Technology Data Exchange (ETDEWEB)
Stepurko, Elena N.; Paulechka, Yauheni U.; Blokhin, Andrey V., E-mail: blokhin@bsu.by; Kabo, Gennady J.; Voitekhovich, Sergei V.; Lyakhov, Alexander S.; Kohut, Sviataslau V.; Kazarovets, Tatiana E.
2014-09-20
Highlights: • Heat capacity, enthalpy of formation, vapor pressure, and enthalpy of sublimation were measured for 5-(1-adamantyl)tetrazole. • Crystal structure of the compound was determined from the X-ray diffraction analysis. • Ideal-gas thermodynamic properties of 5-(1-adamantyl)tetrazole were calculated. - Abstract: Temperature dependence of the heat capacity of 5-(1-adamantyl)tetrazole was studied between (5 and 370) K in a vacuum adiabatic calorimeter. From obtained data the thermodynamic properties of the compound in the condensed state were evaluated over the range of (0–370) K. The crystal structure of 5-(1-adamantyl)tetrazole was determined from the X-ray diffraction analysis. The saturated vapor pressure for crystalline 5-(1-adamantyl)tetrazole in the temperature ranges from (394 to 419) K was measured by the Knudsen effusion method, and its enthalpy of sublimation was obtained using these results. The standard enthalpy of formation for crystalline 5-(1-adamantyl)tetrazole at 298.15 K was determined in a static bomb combustion calorimeter. From these data, the standard enthalpy of formation for gaseous 5-(1-adamantyl)tetrazole was evaluated. The enthalpy of formation calculated using quantum chemical methods is in an excellent agreement with the experimental value. The thermodynamic properties of 5-(1-adamantyl)tetrazole in the ideal-gas state were calculated in the temperature range from (0 to 1000) K. The calculated entropy of gaseous 5-(1-adamantyl)tetrazole is in a good agreement with the one obtained from the experimental data.
Thermodynamic properties of 5-(1-adamantyl)tetrazole
International Nuclear Information System (INIS)
Stepurko, Elena N.; Paulechka, Yauheni U.; Blokhin, Andrey V.; Kabo, Gennady J.; Voitekhovich, Sergei V.; Lyakhov, Alexander S.; Kohut, Sviataslau V.; Kazarovets, Tatiana E.
2014-01-01
Highlights: • Heat capacity, enthalpy of formation, vapor pressure, and enthalpy of sublimation were measured for 5-(1-adamantyl)tetrazole. • Crystal structure of the compound was determined from the X-ray diffraction analysis. • Ideal-gas thermodynamic properties of 5-(1-adamantyl)tetrazole were calculated. - Abstract: Temperature dependence of the heat capacity of 5-(1-adamantyl)tetrazole was studied between (5 and 370) K in a vacuum adiabatic calorimeter. From obtained data the thermodynamic properties of the compound in the condensed state were evaluated over the range of (0–370) K. The crystal structure of 5-(1-adamantyl)tetrazole was determined from the X-ray diffraction analysis. The saturated vapor pressure for crystalline 5-(1-adamantyl)tetrazole in the temperature ranges from (394 to 419) K was measured by the Knudsen effusion method, and its enthalpy of sublimation was obtained using these results. The standard enthalpy of formation for crystalline 5-(1-adamantyl)tetrazole at 298.15 K was determined in a static bomb combustion calorimeter. From these data, the standard enthalpy of formation for gaseous 5-(1-adamantyl)tetrazole was evaluated. The enthalpy of formation calculated using quantum chemical methods is in an excellent agreement with the experimental value. The thermodynamic properties of 5-(1-adamantyl)tetrazole in the ideal-gas state were calculated in the temperature range from (0 to 1000) K. The calculated entropy of gaseous 5-(1-adamantyl)tetrazole is in a good agreement with the one obtained from the experimental data
Thermodynamic properties of actinide aqueous species relevant to geochemical problems
International Nuclear Information System (INIS)
Fuger, J.
1992-01-01
The status of our knowledge of the basic thermodynamic properties of the aqueous complexes of the actinides in their different valency states with two environmentally important ligands, namely hydroxide and carbonate is overviewed. Even in the case of uranium which has been the most studied, gaps are found among the relative wealth of trustworthy formation constants, especially for the less stable valence states. The need for substantial improvement of our knowledge in the case of the other actinides, especially transuranium elements, is outlined. The relative scarcity of enthalpy of formation data is also stressed. (orig.)
Spectroscopic and thermodynamic properties of L-ornithine monohydrochloride
Energy Technology Data Exchange (ETDEWEB)
Raja, M. Dinesh [Department of Physics, Bharath University, Chennai – 600073 (India); Kumar, C. Maria Ashok; Arulmozhi, S.; Madhavan, J., E-mail: jmadhavang@yahoo.com [Department of Physics, Loyola College, Chennai – 600034 (India)
2015-06-24
L-Ornithine Monohydrochloride (LOMHCL) has been investigated with the help of B3LYP density functional theory with 6-31 G (d, p) basis set. Fourier transform infrared and Fourier transform Raman spectra is to identify the various functional groups. The theoretical frequencies showed very good agreement with experimental values. On the basis of the thermodynamic properties of the title compound at different temperatures have been calculated, revealing the correlations between standard heat capacities (C) standard entropies (S), and standard enthalpy changes (H) and temperatures. Second harmonic generation (SHG) efficiency of the grown crystal has been studied.
International Nuclear Information System (INIS)
Chirico, Robert D.; Kazakov, Andrei F.
2015-01-01
Highlights: • Heat capacities were measured for the temperature range (5 to 520) K. • The enthalpy of combustion was measured and the enthalpy of formation was derived. • Thermodynamic-consistency analysis resolved inconsistencies in literature enthalpies of sublimation. • An inconsistency in literature enthalpies of combustion was resolved. • Application of computational chemistry in consistency analysis was demonstrated successfully. - Abstract: Heat capacities and phase-transition properties for xanthone (IUPAC name 9H-xanthen-9-one and Chemical Abstracts registry number [90-47-1]) are reported for the temperature range 5 < T/K < 524. Statistical calculations were performed and thermodynamic properties for the ideal gas were derived based on molecular geometry optimization and vibrational frequencies calculated at the B3LYP/6-31+G(d,p) level of theory. These results are combined with sublimation pressures from the literature to allow critical evaluation of inconsistent enthalpies of sublimation for xanthone, also reported in the literature. Literature values for the enthalpy of combustion of xanthone are re-assessed, a revision is recommended for one result, and a new value for the enthalpy of formation of the ideal gas is derived. Comparisons with thermophysical properties reported in the literature are made for all other reported and derived properties, where possible
Rieger, R; Auregan, J C; Hoc, T
2018-03-01
The objective of the present study is to assess the mechanical behavior of trabecular bone based on microCT imaging and micro-finite-element analysis. In this way two methods are detailed: (i) direct determination of macroscopic elastic property of trabecular bone; (ii) inverse approach to assess mechanical properties of trabecular bone tissue. Thirty-five females and seven males (forty-two subjects) mean aged (±SD) 80±11.7 years from hospitals of Assistance publique-Hôpitaux de Paris (AP-HP) diagnosed with osteoporosis following a femoral neck fracture due to a fall from standing were included in this study. Fractured heads were collected during hip replacement surgery. Standardized bone cores were removed from the femoral head's equator by a trephine in a water bath. MicroCT images acquisition and analysis were performed with CTan ® software and bone volume fraction was then determined. Micro-finite-element simulations were per-formed using Abaqus 6.9-2 ® software in order to determine the macroscopic mechanical behaviour of the trabecular bone. After microCT acquisition, a longitudinal compression test was performed and the experimental macroscopic Young's Modulus was extracted. An inverse approach based on the whole trabecular bone's mechanical response and micro-finite-element analysis was performed to determine microscopic mechanical properties of trabecular bone. In the present study, elasticity of the tissue was shown to be similar to that of healthy tissue but with a lower yield stress. Classical histomorphometric analysis form microCT imaging associated with an inverse micro-finite-element method allowed to assess microscopic mechanical trabecular bone parameters. Copyright © 2017 Elsevier Masson SAS. All rights reserved.
Directory of Open Access Journals (Sweden)
R. A. Bosch
2008-09-01
Full Text Available In a two-stage compression and acceleration system, where each stage compresses a chirped bunch in a magnetic chicane, wakefields affect high-current bunches. The longitudinal wakes affect the macroscopic energy and current profiles of the compressed bunch and cause microbunching at short wavelengths. For macroscopic wavelengths, impedance formulas and tracking simulations show that the wakefields can be dominated by the resistive impedance of coherent edge radiation. For this case, we calculate the minimum initial bunch length that can be compressed without producing an upright tail in phase space and associated current spike. Formulas are also obtained for the jitter in the bunch arrival time downstream of the compressors that results from the bunch-to-bunch variation of current, energy, and chirp. Microbunching may occur at short wavelengths where the longitudinal space-charge wakes dominate or at longer wavelengths dominated by edge radiation. We model this range of wavelengths with frequency-dependent impedance before and after each stage of compression. The growth of current and energy modulations is described by analytic gain formulas that agree with simulations.
Directory of Open Access Journals (Sweden)
Schmidt K.-H.
2010-10-01
Full Text Available A new model description of fission-fragment yields and prompt neutron emission is developed. The yields of the different fission channels and their properties are attributed to the number of relevant states above the potential-energy landscape on the fission path at the moment of dynamical freeze-out, which is specific to the collective coordinate considered. The model combines well established ideas with novel concepts. The separability principle of macroscopic properties of the compound nucleus and microscopic properties of the fragments strongly reduces the number of model parameters and assures a high predictive power. The recently discovered energy-sorting mechanism in superfluid nuclear dynamics determines the sharing of intrinsic excitation energy at scission and the enhancement of even-odd structure in asymmetric splits.
Thermodynamic properties of L-Theanine in different solvents
International Nuclear Information System (INIS)
Zhou, Fuli; Hou, Baohong; Tao, Xiaolong; Hu, Xiaoxue; Huang, Qiaoyin; Zhang, Zaixiang; Wang, Yongli; Hao, Hongxun
2017-01-01
Highlights: • The solubility data of L-Theanine in different solvents were measured by using an equilibrium method. • Several models were used to correlate the experimental solubility data. • The mixing thermodynamic properties were calculated. - Abstract: The solubility data of L-Theanine in pure water and three kinds of water + organic solvent mxitures were measured in temperature ranges from (278.15 to 13.15) K by using an equilibrium method. The results show that the solubility of L-Theanine increases with the increasing of temperature in all selected solvents. The modified Apelblat equation and the λ-h model were applied to correlate the solubility data in pure water, while the modified Apelblat equation, the λ-h model, the NRTL model and the Jouyban–Acree model were applied to correlate the solubility data in binary solvent mixtures. Furthermore, the mixing thermodynamic properties of L-Theanine in different solvents were also calculated based on the NRTL model and experimental solubility data.
Thermodynamic properties of soddyite from solubility and calorimetry measurements
International Nuclear Information System (INIS)
Gorman-Lewis, Drew; Mazeina, Lena; Fein, Jeremy B.; Szymanowski, Jennifer E.S.; Burns, Peter C.; Navrotsky, Alexandra
2007-01-01
The release of uranium from geologic nuclear waste repositories under oxidizing conditions can only be modeled if the thermodynamic properties of the secondary uranyl minerals that form in the repository setting are known. Toward this end, we synthesized soddyite ((UO 2 ) 2 (SiO 4 )(H 2 O) 2 ), and performed solubility measurements from both undersaturation and supersaturation. The solubility measurements rigorously constrain the value of the solubility product of synthetic soddyite, and consequently its standard-state Gibbs free energy of formation. The log solubility product (lg K sp ) with its error (1σ) is (6.43 + 0.20/-0.37), and the standard-state Gibbs free energy of formation is (-3652.2 ± 4.2 (2σ)) kJ mol -1 . High-temperature drop solution calorimetry was conducted, yielding a calculated standard-state enthalpy of formation of soddyite of (-4045.4 ± 4.9 (2σ)) kJ . mol -1 . The standard-state Gibbs free energy and enthalpy of formation yield a calculated standard-state entropy of formation of soddyite of (-1318.7 ± 21.7 (2σ)) J . mol -1 . K -1 . The measurements and associated thermodynamic calculations not only describe the T = 298 K stability and solubility of soddyite, but they also can be used in predictions of repository performance through extrapolation of these properties to repository temperatures
Calculation of thermodynamic properties using the random-phase approximation: alpha-N2
Jansen, A.P.J.; Schoorl, R.
1988-01-01
The random-phase approximation (RPA) for molecular crystals is extended in order to calculate thermodynamic properties. A recursion formula for thermodynamic averages of products of mean-field excitation and deexcitation operators is derived. With this formula the thermodynamic average of any
On the thermodynamic properties of the generalized Gaussian core model
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B.M.Mladek
2005-01-01
Full Text Available We present results of a systematic investigation of the properties of the generalized Gaussian core model of index n. The potential of this system interpolates via the index n between the potential of the Gaussian core model and the penetrable sphere system, thereby varying the steepness of the repulsion. We have used both conventional and self-consistent liquid state theories to calculate the structural and thermodynamic properties of the system; reference data are provided by computer simulations. The results indicate that the concept of self-consistency becomes indispensable to guarantee excellent agreement with simulation data; in particular, structural consistency (in our approach taken into account via the zero separation theorem is obviously a very important requirement. Simulation results for the dimensionless equation of state, β P / ρ, indicate that for an index-value of 4, a clustering transition, possibly into a structurally ordered phase might set in as the system is compressed.
Chakraborty, Anutosh; Saha, Bidyut Baran; Ng, Kim Choon; Koyama, Shigeru; Srinivasan, Kandadai
2009-01-01
Thermodynamic property surfaces for a single-component adsorbent + adsorbate system are derived and developed from the viewpoint of classical thermodynamics, thermodynamic requirements of chemical equilibrium, Gibbs law, and Maxwell relations
Thermodynamic properties of 1-phenylnaphthalene and 2-phenylnaphthalene
International Nuclear Information System (INIS)
Chirico, Robert D.; Steele, William V.; Kazakov, Andrei F.
2014-01-01
Highlights: • Heat capacities, vapor pressures, enthalpies of combustion, and densities were measured for 1-phenylnaphthalene (1-PhN). • Heat capacities and vapor pressures were measured for 2-phenylnaphthalene (2-PhN). • Independent ideal-gas entropies derived with the calorimetric results and statistical methods are in accord for 1-PhN. • 2-PhN showed glassy-crystal behavior in the solid state, and an entropy deficit is demonstrated. - Abstract: Measurements leading to the calculation of thermodynamic properties in the ideal-gas state for 1-phenylnaphthalene (Chemical Abstracts registry number [605-02-7]) and 2-phenylnaphthalene (Chemical Abstracts registry number [612-94-2]) are reported. Experimental methods for 1-phenylnaphthalene were adiabatic heat-capacity calorimetry, differential scanning calorimetry, inclined-piston manometry, comparative ebulliometry, vibrating-tube densitometry, and combustion calorimetry. For 2-phenylnaphthalene, the experimental methods were adiabatic heat-capacity calorimetry, differential scanning calorimetry, and comparative ebulliometry. Critical properties were estimated for both compounds. Molar thermodynamic functions (enthalpies, entropies, and Gibbs free energies) for the condensed and ideal-gas states were derived from the experimental studies at selected temperatures. Statistical calculations were performed based on molecular geometry optimization and vibrational frequencies calculated at the B3LYP/6-31+G(d, p) and B3LYP/cc-pVTZ levels of theory. Ideal-gas entropies derived with two the independent methods are shown to be in good accord for 1-phenylnaphthalene, but significant differences are apparent for 2-phenylnaphthalene. These differences are likely due to a disorder of unknown type in the crystals of 2-phenylnaphthalene at low temperatures, as evidenced by the presence of a glass-like transition in the measured heat capacities for the solid state. All experimental results are compared with property values
Institute of Scientific and Technical Information of China (English)
Liang Kou; Yingjun Liu; Cheng Zhang; Le Shao; Zhanyuan Tian; Zengshe Deng; Chao Gao
2017-01-01
Nanocarbon-based materials, such as carbon nanotubes(CNTs) and graphene have been attached much attention by scientific and industrial community. As two representative nanocarbon materials, one-dimensional CNTs and twodimensional graphene both possess remarkable mechanical properties. In the past years, a large amount of work have been done by using CNTs or graphene as building blocks for constructing novel, macroscopic, mechanically strong fibrous materials. In this review, we summarize the assembly approaches of CNT-based fibers and graphene-based fibers in chronological order, respectively. The mechanical performances of these fibrous materials are compared, and the critical influences on the mechanical properties are discussed. Personal perspectives on the fabrication methods of CNT-and graphene-based fibers are further presented.
Phonon spectra, electronic, and thermodynamic properties of WS2 nanotubes.
Evarestov, Robert A; Bandura, Andrei V; Porsev, Vitaly V; Kovalenko, Alexey V
2017-11-15
Hybrid density functional theory calculations are performed for the first time on the phonon dispersion and thermodynamic properties of WS 2 -based single-wall nanotubes. Symmetry analysis is presented for phonon modes in nanotubes using the standard (crystallographic) factorization for line groups. Symmetry and the number of infra-red and Raman active modes in achiral WS 2 nanotubes are given for armchair and zigzag chiralities. It is demonstrated that a number of infrared and Raman active modes is independent on the nanotube diameter. The zone-folding approach is applied to find out an impact of curvature on electron and phonon band structure of nanotubes rolled up from the monolayer. Phonon frequencies obtained both for layers and nanotubes are used to compute the thermal contributions to their thermodynamic functions. The temperature dependences of energy, entropy, and heat capacity of nanotubes are estimated with respect to those of the monolayer. The role of phonons in the stability estimation of nanotubes is discussed based on Helmholtz free energy calculations. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.
Water adsorption isotherms and thermodynamic properties of cassava bagasse
International Nuclear Information System (INIS)
Polachini, Tiago Carregari; Betiol, Lilian Fachin Leonardo; Lopes-Filho, José Francisco; Telis-Romero, Javier
2016-01-01
Highlights: • Adsorption isotherms and composition of cassava bagasse were determined. • GAB equation was the best-fitted model to sorption data of type II isotherm. • Isosteric heat of sorption was calculated in a range of equilibrium moisture content. • Differential enthalpy and entropy confirmed the isokinetic compensation theory. • Water adsorption by cassava bagasse is considered an enthalpy driven process. - Abstract: Losses of food industry are generally wet products that must be dried to posterior use and storage. In order to optimize drying processes, the study of isotherms and thermodynamic properties become essential to understand the water sorption mechanisms of cassava bagasse. For this, cassava bagasse was chemically analyzed and had its adsorption isotherms determined in the range of 293.15–353.15 K through the static gravimetric method. The models of GAB, Halsey, Henderson, Oswin and Peleg were fitted, and best adjustments were found for GAB model with R"2 > 0.998 and no pattern distribution of residual plots. Isosteric heat of adsorption and thermodynamic parameters could be determined as a function of moisture content. Compensation theory was confirmed, with linear relationship between enthalpy and entropy and higher values of isokinetic temperature (T_B = 395.62 K) than harmonic temperature. Water adsorption was considered driven by enthalpy, clarifying the mechanisms of water vapor sorption in cassava bagasse.
Thermodynamic properties of some gallium-based binary alloys
International Nuclear Information System (INIS)
Awe, O.E.; Odusote, Y.A.; Akinlade, O.; Hussain, L.A.
2008-01-01
We have studied the concentration dependence of the free energy of mixing, concentration-concentration fluctuations in the long-wavelength limit, the chemical short-range order parameter, the enthalpy and entropy of mixing of Ga-Zn, Ga-Mg and Al-Ga binary alloys at different temperatures using a quasi-chemical approximation for compound forming binary alloys and that for simple regular alloys. From the study of the thermodynamic quantities, we observed that thermodynamic properties of Ga-Zn and Al-Ga exhibit positive deviations from Raoultian behaviour, while Ga-Mg exhibits negative deviation. Hence, this study reveals that both Ga-Zn and Al-Ga are segregating systems, while chemical order exists in Ga-Mg alloy in the whole concentration range. Furthermore, our investigation indicate that Al-Ga binary alloy have a tendency to exhibit ideal mixture behaviour in the concentration range 0≤c Al ≤0.30 and 0.7≤c Al ≤1
Thermodynamic and kinetic properties of amorphous and liquid states
International Nuclear Information System (INIS)
Granato, A.V.
1998-01-01
The magnitude and temperature dependence of the liquid state shear modulus G, specific heat C p , diffusivity D, and viscosity η should all be closely related, according to the interstitialcy model, if a recent proposal by Dyre et al. is generally true. They suppose that the viscosity is given by η = η 0 exp (F/kT), where η 0 is a reference viscosity and F is given by the work required to shove aside neighboring particle in a diffusion process, where F = GV c and V c is a characteristic volume. In the interstitialcy model the high frequency thermodynamic liquid state shear modulus is given by G(T) = G 0 exp [-γ(T/T 0 - 1)], where G 0 is the shear modulus at a reference temperature T 0 , which can be taken as the glass temperature. The resulting non-Arrhenius behavior of the viscosity is compared with experimental data. A critical quantitative analysis for a Zr 41.2 Ti 13.8 Cu 12.5 Ni 10 Be 225 alloy does not support the shoving model, but the thermodynamic properties can be understood in terms of mixed interstitials composed of metal-beryllium complexes
International Nuclear Information System (INIS)
Zanchini, E.
1988-01-01
The definition of energy, in thermodynamics, is dependent by starting operative definitions of the basic concepts of physics on which it rests, such as those of isolated systems, ambient of a system, separable system and set of separable states. Then the definition of energy is rigorously extended to open systems. The extension gives a clear physical meaning to the concept of energy difference between two states with arbitrary different compositions
Probing the surface properties of a polymer glass with macroscopic friction
International Nuclear Information System (INIS)
Bureau, Lionel
2007-01-01
We show how macroscopic friction can be used as a sensitive probe of chain dynamics at the surface of a glassy polymer. We present experiments in which a smooth poly(methylmethacrylate) (PMMA) solid slides on flat surfaces presenting different densities of pinning sites available for polymer/substrate bond formation. These experiments indicate that: (i) at high pinning level, frictional dissipation occurs through the sudden flips of molecular-sized bistable regions localized in a nm-thick layer of confined chains, which responds to shear as an elasto-plastic solid, and (ii) in situations of weak pinning, dissipation appears to be governed by a process akin to that proposed for rubber friction. This suggests that some 'glass-to-rubber' transition occurs at the polymer surface when its interaction with the substrate goes from strong to weak. The temperature-dependence of friction provides further support for the presence of a nm-thick layer at the polymer surface, which exhibits a rubberlike response in situation of weak interaction with the countersurface. This behavior results from the interplay between viscous flow in this surface layer, and shear induced depinning of adsorbed surface chains. Moreover, a quantitative analysis of the results indicates that the pinning dynamics of polymer chains is controlled by localized β rotational motions at the interface
International Nuclear Information System (INIS)
Simonovski, Igor; Cizelj, Leon; Garrido, Oriol Costa
2013-01-01
Highlights: ► Grain boundary stiffness should be at least 1.5× higher that the stiffness of bulk grains. ► The ratio δ n pl /δ n el should be at least 400. ► Simultaneous increase of δ n el and δ n pl at constant grain boundary strength increases numerical stability but results in high percentage of damage grain boundary area. ► Shear contributes significantly to damage initialization. -- Abstract: In this work a model, based on a X-ray diffraction contrast tomography data of a stainless steel wire with a diameter of 0.4 mm is presented. As measured 3D grain geometry and crystallographic orientation of individual grains are directly transferred into a finite element model. Anisotropic elasticity and crystal plasticity constitutive laws are used for the bulk grain material while the grain boundaries are explicitly modeled using the cohesive zone approach. A parametric study on the effects of the grain boundary strength and other cohesive zone parameters on the macroscopic response and damaged grain boundary area of a polycrystalline aggregate is presented. Recommendations for the cohesive zone parameters values aimed at achieving low damaged grain boundary area during numerical tensile tests are given while at the same time taking into account the numerical stability of the simulations
Energy Technology Data Exchange (ETDEWEB)
Simonovski, Igor, E-mail: Igor.Simonovski@ec.europa.eu [European Commission, DG-JRC, Institute for Energy and Transport, P.O. Box 2, NL-1755 ZG Petten (Netherlands); Cizelj, Leon, E-mail: Leon.Cizelj@ijs.si [Jožef Stefan Institute, Reactor Engineering Division, Jamova Cesta 39, SI-1000 Ljubljana (Slovenia); Garrido, Oriol Costa, E-mail: Oriol.Costa@ijs.si [Jožef Stefan Institute, Reactor Engineering Division, Jamova Cesta 39, SI-1000 Ljubljana (Slovenia)
2013-08-15
Highlights: ► Grain boundary stiffness should be at least 1.5× higher that the stiffness of bulk grains. ► The ratio δ{sub n}{sup pl}/δ{sub n}{sup el} should be at least 400. ► Simultaneous increase of δ{sub n}{sup el} and δ{sub n}{sup pl} at constant grain boundary strength increases numerical stability but results in high percentage of damage grain boundary area. ► Shear contributes significantly to damage initialization. -- Abstract: In this work a model, based on a X-ray diffraction contrast tomography data of a stainless steel wire with a diameter of 0.4 mm is presented. As measured 3D grain geometry and crystallographic orientation of individual grains are directly transferred into a finite element model. Anisotropic elasticity and crystal plasticity constitutive laws are used for the bulk grain material while the grain boundaries are explicitly modeled using the cohesive zone approach. A parametric study on the effects of the grain boundary strength and other cohesive zone parameters on the macroscopic response and damaged grain boundary area of a polycrystalline aggregate is presented. Recommendations for the cohesive zone parameters values aimed at achieving low damaged grain boundary area during numerical tensile tests are given while at the same time taking into account the numerical stability of the simulations.
Equation of state and thermodynamic properties of BCC metals
Directory of Open Access Journals (Sweden)
Vu Van Hung, N.T. Hoa
2017-10-01
Full Text Available The moment method in statistical dynamics is used to study the equation of state and thermodynamic properties of the bcc metals taking into account the anharmonicity effects of the lattice vibrations and hydrostatic pressures. The explicit expressions of the lattice constant, thermal expansion oefficient, and the specific heats of the bcc metals are derived within the fourth order moment approximation. The termodynamic quantities of W, Nb, Fe,and Ta metals are calculated as a function of the pressure, and they are in good agreement with the corresponding results obtained from the first principles calculations and experimental results. The effective pair potentials work well for the calculations of bcc metals.
Czech Academy of Sciences Publication Activity Database
Kroupa, Aleš
2013-01-01
Roč. 66, JAN (2013), s. 3-13 ISSN 0927-0256 R&D Projects: GA MŠk(CZ) OC08053 Institutional support: RVO:68081723 Keywords : Calphad method * phase diagram modelling * thermodynamic database development Subject RIV: BJ - Thermodynamics Impact factor: 1.879, year: 2013
Structure, thermodynamics, and dynamical properties of supercooled liquids
International Nuclear Information System (INIS)
Kambayashi, Shaw
1992-12-01
The equilibrium properties of supercooled liquids with repulsive soft-sphere potentials, u(r) = ε(σ/r) n , have been obtained by solving the integral equation of the theory of liquids and by performing constant-temperature molecular dynamics (MD) simulations. A thermodynamically consistent approximation, proposed recently by Rogers and Young (RY), has been examined for the supercooled soft-sphere fluids. Then, a new approximation for the integral equation, called MHNCS (modified hypernetted-chain integral equation for highly supercooled soft-sphere fluids) approximation, is proposed. The solution of the MHNCS integral equation for highly supercooled liquid states agrees well with the results of computer simulations. The MHNCS integral equation has also been applied for binary soft-sphere mixtures. Dynamical properties of soft-sphere fluids have been investigated by molecular dynamics (MD) simulations. The reduced diffusion constant is found to be insensitive to the choice of the softness of the potential. On the other hand, the spectrum of the velocity autocorrelation function shows a pronounced dependence on the softness of the potential. These significant dynamical properties dependent on the softness parameter (n) are consistent to dynamical behavior observed in liquid alkali metals and liquefied inert gases. The self-part of the density-density autocorrelation function obtained shows a clear nonexponential decay in intermediate time, as the liquid-glass transition is approached. (J.P.N.) 105 refs
Thermodynamic Property Model of Wide-Fluid Phase Propane
Directory of Open Access Journals (Sweden)
I Made Astina
2007-05-01
Full Text Available A new thermodynamic property model for propane is expressed in form of the Helmholtz free energy function. It consists of eight terms of the ideal-gas part and eighteen terms of the residual part. Accurate experimental data of fluid properties and theoretical approach from the intermolecular potential were simultaneously considered in the development to insure accuracy and to improve reliability of the equation of state over wide range of pressures and temperatures. Based on the state range of experimental data used in the model development, the validity range is judged from the triple-point of 85.48 K to temperature of 450 K and pressure up to 60 MPa. The uncertainties with respect to different properties are estimated to be 0.03% in ideal-gas isobaric specific heat, 0.2% in liquid phase density, 0.3% in gaseous phase density 1% in specific heats, 0.1% in vapor-pressure except at very low temperatures, 0.05% in saturated-liquid density, 0.02% in speed of sound of the gaseous phase and 1% in speed of sound of the liquid phase.
International Nuclear Information System (INIS)
Shpil'rain, E.E.; Yakimovich, K.A.
1981-01-01
The paper reviews briefly experimental determinations of thermodynamic properties of the LiH-Li system. Relationships fitted to the experimental data are presented and discussed, with the aim of determining a consistent set of thermodynamic properties (enthalpy, heat capacity) for the systems Li-(LiH, LiD, LiT) in the solid state and in the melt. (author)
Ideal gas thermodynamic properties for the phenyl, phenoxy, and o-biphenyl radicals
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.
International Nuclear Information System (INIS)
Kuksa, L.V.; Arzamaskova, L.M.
2000-01-01
The results of studies on elastic and plastic properties of the single- and two-phase polycrystalline materials in dependence on the choice of the consideration scale level are presented. The experimental and theoretical methods, making it possible to study the role of the scale factor by consideration on the micro- and macrolevel and the peculiarities of forming the physicomechanical properties of the material as a whole, are developed. The dependences, characterizing the change of the physicomechanical properties by different scales of consideration, are obtained [ru
Thermodynamic properties of chemical species of waste radionuclides
International Nuclear Information System (INIS)
Silva, R.J.; Nitsche, H.
1984-01-01
The object of the experimental program at Lawrence Berkeley Laboratory is to identify gaps or conflicts in thermodynamic data on the solubilities of compounds and on the formation of solution complexes of waste radionuclides needed for the reliable prediction of solution concentrations. It involves laboratory measurements necessary to (1) generate specific new data, where none exists, in order to demonstrate the importance of a particular solution species, compound or solution parameter (e.g., temperature, Eh) and to (2) resolve conflicts in existing thermodynamic data on important species or compounds. The measurement of the solubility of AmOHCO 3 in 0.1 M NaClO 4 at 25 0 C and 1 atmosphere pressure has been completed. From the experimental data, an average solubility product quotient, Qsp, was evaluated for the reaction, AmOHCO 3 (S) + 2H + = Am 3+ + HCO 3 - + H 2 O. The logarithm of Qsp was calculated to be 2.74 +/- .17. Speciation calculations, using this new data plus reported data on the solubility of Am(OH) 3 and the hydrolysis and carbonate complexation of Am 3+ , indicate that the presence of carbonate can have a substantial effect on the nature of compounds and solution species formed by americium in ground waters. Since actinides in a given oxidation state tend to exhibit similar chemical properties, this result should apply to other actinides in the trivalent state. Thus, the effect of carbonate on the solubilities and complexation of trivalent actinides should be included in any predictive modelling studies required for licensing. 27 references, 4 figures, 5 tables
Interphase thermodynamic bond in heterogeneous alloys: effects on alloy properties
International Nuclear Information System (INIS)
Savchenko, A.M.; Konovalov, Yu.V.; Yuferov, O.I.
2005-01-01
Inconsistency between a conventional thermodynamic description of alloys as a mechanical mixture of phases and a real alloys state as a common thermodynamic system in which there is a complicated physical-chemical phases interaction has been considered. It is supposed that in heterogeneous alloys (eutectic ones, for instance), so called interphase thermodynamic bond can become apparent due to a partial electron levels splitting under phase interaction. Thermodynamic description of phase equilibrium in alloys is proposed taking into account a thermodynamic bond for the system with phase diagram of eutectic type, and methods of the value of this bond estimation are presented. Experimental evidence (Al-Cu-Si, Al-Si-Mg-Cu, U-Mo + Al) of the effect of interphase thermodynamic bond on temperature and enthalpy of melting of alloys are produced as well as possibility of its effects on alloys electrical conduction, strength, heat and corrosion resistance is substantiated theoretically [ru
THEWASP library. Thermodynamic water and steam properties library in GPU
International Nuclear Information System (INIS)
Waintraub, M.; Lapa, C.M.F.; Mol, A.C.A.; Heimlich, A.
2011-01-01
In this paper we present a new library for thermodynamic evaluation of water properties, THEWASP. This library consists of a C++ and CUDA based programs used to accelerate a function evaluation using GPU and GPU clusters. Global optimization problems need thousands of evaluations of the objective functions to nd the global optimum implying in several days of expensive processing. This problem motivates to seek a way to speed up our code, as well as to use MPI on Beowulf clusters, which however increases the cost in terms of electricity, air conditioning and others. The GPU based programming can accelerate the implementation up to 100 times and help increase the number of evaluations in global optimization problems using, for example, the PSO or DE Algorithms. THEWASP is based on Water-Steam formulations publish by the International Association for the properties of water and steam, Lucerne - Switzerland, and provides several temperature and pressure function evaluations, such as specific heat, specific enthalpy, specific entropy and also some inverse maps. In this study we evaluated the gain in speed and performance and compared it a CPU based processing library. (author)
Correlation between thermodynamic and mechanical properties in Ta-W
Energy Technology Data Exchange (ETDEWEB)
Hoppe, Sandra; Mueller, Stefan [Institute of Advanced Ceramics, Hamburg University of Technology, Hamburg (Germany)
2015-07-01
Varying an alloy's concentration or alloying constituents strongly influences its structural and mechanical properties. Modern simulation methods like density functional theory in combination with the cluster expansion make the whole configurational space accessible. This way, also metastable structures may be considered, which are experimentally difficult to obtain. Recent results for several face-centered cubic (fcc) binary metal alloys suggest a linear correlation between thermodynamic stability and elastic properties at a fixed stoichiometry. This study aims to investigate the generality of these findings by considering a similar correlation for binary body-centered cubic (bcc) alloys. As a model system, Ta-W was chosen due to its simple phase diagram with solid solution in the whole concentration range. Interestingly, the elastic constants c{sub 44} and c{sub 12} show an opposing trend to that observed for fcc alloys: Energetically favorable structures are mechanically weaker than those further away from the ground-state line. This phenomenon may be related to the anomalous behavior of c{sub 44} with increasing pressure or temperature, which has been reported in the literature for Ta-W. We will discuss the interesting behavior of Ta-W with regard to its electronic structure.
Thermodynamic properties of 5(nitrophenyl) furan-2-carbaldehyde isomers.
Dibrivnyi, Volodymyr; Sobechko, Iryna; Puniak, Marian; Horak, Yuriy; Obushak, Mykola; Van-Chin-Syan, Yuriy; Andriy, Marshalek; Velychkivska, Nadiia
2015-01-01
The aim of the current work was to determine thermo dynamical properties of 5(2-nitro phenyl)-furan-2-carbaldehyde, 5(3-nitro phenyl)-furan-2-carbaldehyde and 5(4-nitro phenyl)-furan-2-carbaldehyde. The temperature dependence of saturated vapor pressure of 5(2-nitro phenyl)-furan-2-carbaldehyde, 5(3-nitro phenyl)-furan-2-carbaldehyde and 5(4-nitro phenyl)-furan-2-carbaldehyde was determined by Knudsen's effusion method. The results are presented by the Clapeyron-Clausius equation in linear form, and via this form, the standard enthalpies, entropies and Gibbs energies of sublimation and evaporation of compounds were calculated at 298.15 K. The standard molar formation enthalpies of compounds in crystalline state at 298.15 K were determined indirectly by the corresponding standard molar combustion enthalpy, obtained using bomb calorimetry combustion. Determination of the thermodynamic properties for these compounds may contribute to solving practical problems pertaining optimization processes of their synthesis, purification and application and it will also provide a more thorough insight regarding the theoretical knowledge of their nature.Graphical abstract:Generalized structural formula of investigated compounds and their formation enthalpy determination scheme in the gaseous state.
Thermodynamic and transport properties of YbNi 4Cd
Lee, J.; Park, H.; Lee-Hone, N. R.; Broun, D. M.; Mun, E.
2018-05-01
The single crystal growth and the physical properties of the intermetallic compounds R Ni4Cd (R =Y and Yb) which crystallize in the face-centered cubic (fcc) MgCu4Sn -type structure (space group F 4 ¯3 m ) are discussed. Thermodynamic and transport properties of YbNi4Cd are studied by measuring the magnetization, electrical resistivity, and specific heat. The magnetic susceptibility measurement shows that the 4 f electrons of Yb3 + ions are well localized. The electrical resistivity and specific heat exhibits an antiferromagnetic ordering below TN=0.97 K. Applying the field along the [111] direction results in the suppression of TN below 0.4 K at the critical field Hc˜4.5 kOe. No non-Fermi liquid behavior has been observed in the vicinity of Hc. Above Hc, the magnetoresistivity shows an unconventional temperature dependence ρ (T ) =ρ0+A Tn with n >2 , suggesting that an additional scattering mechanism in the resistivity needs to be considered. Based on the analysis of experimental results, we conclude that the Yb3 + moments and conduction electrons are weakly coupled. Despite the antiferromagnetic ordering below TN, YbNi4Cd exhibits a large frustration parameter | θp/TN|˜16 , where the magnetic Yb3 + ions occupy the tetrahedra on the fcc lattice.
An approach to get thermodynamic properties from speed of sound
International Nuclear Information System (INIS)
Núñez, M A; Medina, L A
2017-01-01
An approach for estimating thermodynamic properties of gases from the speed of sound u, is proposed. The square u 2 , the compression factor Z and the molar heat capacity at constant volume C V are connected by two coupled nonlinear partial differential equations. Previous approaches to solving this system differ in the conditions used on the range of temperature values [T min ,T max ]. In this work we propose the use of Dirichlet boundary conditions at T min , T max . The virial series of the compression factor Z = 1+Bρ+Cρ 2 +… and other properties leads the problem to the solution of a recursive set of linear ordinary differential equations for the B, C. Analytic solutions of the B equation for Argon are used to study the stability of our approach and previous ones under perturbation errors of the input data. The results show that the approach yields B with a relative error bounded basically by that of the boundary values and the error of other approaches can be some orders of magnitude lager. (paper)
Systemic analysis of thermodynamic properties of lanthanide halides
International Nuclear Information System (INIS)
Mirsaidov, U.; Badalov, A.; Marufi, V.K.
1992-01-01
System analysis of thermodynamic characteristics of lanthanide halides was carried out. A method making allowances for the influence of spin and orbital moments of momentum of the main states of lanthanide trivalent ions in their natural series was employed. Unknown in literature thermodynamic values were calculated and corrected for certain compounds. The character of lanthanide halide thermodynamic parameter change depending on ordinal number of the metals was ascertained. Pronouncement of tetrad-effect in series of compounds considered was pointed out
Modeling the Thermodynamic Properties of the Inner Comae of Comets
Boice, Daniel C.
2017-10-01
Introduction: Modeling is central to understand the important properties of the cometary environment. We have developed a comet model, SUISEI, that self-consistently includes the relevant physicochemical processes within a global modeling framework, from the porous subsurface layers of the nucleus to the interaction with the solar wind. Our goal is to gain valuable insights into the intrinsic properties of cometary nuclei so we can better understand observations and in situ measurements. SUISEI includes a multifluid, reactive gas dynamics simulation of the dusty coma (ComChem) and a suite of other coupled numerical simulations. This model has been successfully applied to a variety of comets in previous studies over the past three decades. We present results from a quantitative study of the thermodynamic properties and chemistry of cometary comae as a function of cometocentric and heliocentric distance to aid in interpretation of observations and in situ measurements of comets.Results and Discussion: ComChem solves the fluid dynamic equations for the mass, momentum, and energy of three neutral fluids (H, H2, and the heavier bulk fluid), ions, and electrons. In the inner coma, the gas expands, cools, accelerates, and undergoes many photolytic and gas-phase chemical reactions tracking hundreds of sibling species. The code handles the transition to free molecular flow and describes the spatial distribution of species in the coma of a comet. Variations of neutral gas temperature and velocity with cometocentric distance and heliocentric distance for a comet approaching the Sun from 2.5 to 0.3 AU are presented. Large increases in the gas temperatures (>400 K) due to photolytic heating in the coma within ~0.5 AU are noted, with dramatic effects on the chemistry, optical depth, and other coma properties. Results are compared to observations when available.Conclusions: SUISEI has proven to be a unique and valuable model to understand the relevant physical processes and
Critical, statistical, and thermodynamical properties of lattice models
Energy Technology Data Exchange (ETDEWEB)
Varma, Vipin Kerala
2013-10-15
In this thesis we investigate zero temperature and low temperature properties - critical, statistical and thermodynamical - of lattice models in the contexts of bosonic cold atom systems, magnetic materials, and non-interacting particles on various lattice geometries. We study quantum phase transitions in the Bose-Hubbard model with higher body interactions, as relevant for optical lattice experiments of strongly interacting bosons, in one and two dimensions; the universality of the Mott insulator to superfluid transition is found to remain unchanged for even large three body interaction strengths. A systematic renormalization procedure is formulated to fully re-sum these higher (three and four) body interactions into the two body terms. In the strongly repulsive limit, we analyse the zero and low temperature physics of interacting hard-core bosons on the kagome lattice at various fillings. Evidence for a disordered phase in the Ising limit of the model is presented; in the strong coupling limit, the transition between the valence bond solid and the superfluid is argued to be first order at the tip of the solid lobe.
Thermodynamic properties and drying kinetics of Bauhinia forficata Link leaves
Directory of Open Access Journals (Sweden)
Fernanda P. da Silva
Full Text Available ABSTRACT The aim of this study was to determine the effective diffusion coefficient and the thermodynamic properties of Bauhinia forficata Link leaves, considering two forms of thickness measurements and to describe the process by fitting mathematical models. The leaves were collected, taken to the laboratory and prepared to start the drying process in which four temperatures (40, 50, 60 and 70 °C were applied. After the drying process, the effective diffusion coefficient was determined through the theory of diffusion in liquid, allowing to obtain the values of the activation energy, enthalpy, entropy and Gibbs free energy. The description of the drying process was performed by setting the thirteen mathematical models used to represent constant drying of agricultural products. The Valcam model was selected to represent the drying kinetics B. forficata Link. Increased temperature promotes: decreasing enthalpy and entropy; increasing Gibbs free energy and effective diffusion coefficient. The effective diffusion coefficient is higher when the rib thickness is considered; thus, it is recommended to standardize and/or specify the points of measurement of leaf thickness.
Critical, statistical, and thermodynamical properties of lattice models
International Nuclear Information System (INIS)
Varma, Vipin Kerala
2013-10-01
In this thesis we investigate zero temperature and low temperature properties - critical, statistical and thermodynamical - of lattice models in the contexts of bosonic cold atom systems, magnetic materials, and non-interacting particles on various lattice geometries. We study quantum phase transitions in the Bose-Hubbard model with higher body interactions, as relevant for optical lattice experiments of strongly interacting bosons, in one and two dimensions; the universality of the Mott insulator to superfluid transition is found to remain unchanged for even large three body interaction strengths. A systematic renormalization procedure is formulated to fully re-sum these higher (three and four) body interactions into the two body terms. In the strongly repulsive limit, we analyse the zero and low temperature physics of interacting hard-core bosons on the kagome lattice at various fillings. Evidence for a disordered phase in the Ising limit of the model is presented; in the strong coupling limit, the transition between the valence bond solid and the superfluid is argued to be first order at the tip of the solid lobe.
Moisture sorption isotherms and thermodynamic properties of bovine leather
Fakhfakh, Rihab; Mihoubi, Daoued; Kechaou, Nabil
2018-04-01
This study was aimed at the determination of bovine leather moisture sorption characteristics using a static gravimetric method at 30, 40, 50, 60 and 70 °C. The curves exhibit type II behaviour according to the BET classification. The sorption isotherms fitting by seven equations shows that GAB model is able to reproduce the equilibrium moisture content evolution with water activity for moisture range varying from 0.02 to 0.83 kg/kg d.b (0.9898 thermodynamic properties such as isosteric heat of sorption, sorption entropy, spreading pressure, net integral enthalpy and entropy. Net isosteric heat of sorption and differential entropy were evaluated through direct use of moisture isotherms by applying the Clausius-Clapeyron equation and used to investigate the enthalpy-entropy compensation theory. Both sorption enthalpy and entropy for desorption increase to a maximum with increasing moisture content, and then decrease sharply with rising moisture content. Adsorption enthalpy decreases with increasing moisture content. Whereas, adsorption entropy increases smoothly with increasing moisture content to a maximum of 6.29 J/K.mol. Spreading pressure increases with rising water activity. The net integral enthalpy seemed to decrease and then increase to become asymptotic. The net integral entropy decreased with moisture content increase.
Structure and thermodynamic properties of molten alkali chlorides
International Nuclear Information System (INIS)
Ballone, P.; Pastore, G.; Tosi, M.P.; Trieste Univ.
1984-03-01
Self-consistent calculations of partial pair distribution functions and thermodynamic properties are presented for molten alkali chlorides in a non-polarizable-ion model. The theory starts from the hypernetted chain approximation and analyzes the role of bridge diagrams both for a two-component ionic plasma on a neutralizing background and for a binary ionic liquid of cations and anions. A simple account of excluded-volume effects suffices for a good description of the pair distribution functions in the two-component plasma, in analogy with earlier work on one-component fluids. The interplay of Coulomb attractions and repulsions in the molten salt requires, on the other hand, the inclusion of (i) excluded-volume effects for the various ion pairs as in a mixture of hard spheres with non-additive radii and (ii) medium-range Coulomb effects reflected mainly in the like-ion correlations. All these effects are included approximately in an empirical evaluation of the bridge functions, with numerical results which compare very well with computer simulation data. A detailed discussion of the results against experimental structural data is then given in the case of molten sodium chloride. (author)
Structure and thermodynamic properties of molten strontium chloride
International Nuclear Information System (INIS)
Pastore, G.; Ballone, P.; Tosi, M.P.; Trieste Univ.
1985-05-01
Self-consistent calculations of pair distribution functions and thermodynamic properties are presented for a pair-potentials model of molten strontium chloride. The calculations extend to a strongly asymmetric ionic liquid an earlier assessment of bridge diagrams in a modified hypernetted chain approach to the liquid structure of alkali halides. Good agreement is found with computer simulation data obtained by de Leeuw with the same set of pair potentials, showing that the present approach incorporates genuine general features of liquid structure theory for multicomponent liquids with strong relative ordering of the component species. It is further shown that the strong correlations between the divalent cations, both in the model and in real molten strontium chloride, can be approximately reproduced on the basis of a simple one-component-plasma model, provided that dielectric screening is allowed for in the real liquid. This allows us to tentatively attribute the significant level of disagreement between a pair potentials model of this liquid and the neutron diffraction data of McGreevy and Mitchell to many-body distortions of the electronic shells of the ions. (author)
Thermodynamic properties of chromium bearing slags and minerals. A review
Energy Technology Data Exchange (ETDEWEB)
Xiao Yanping; Holappa, L.
1996-12-31
In this report, the thermodynamic properties of chromium bearing slags and minerals were reviewed based on the available information in the literature. It includes the analysing methods for oxidation state of chromium in slags, oxidation state of chromium and activities of chromium oxides in slags and minerals. The phase diagrams of chromium oxide systems and chromium distributions between slag and metal phases are also covered ill this review. Concerning the analysing methods, it was found that most of the available approaches are limited to iron free slag systems and the sample preparation is very sensitive to the analysing results. In silicate slags under reducing atmosphere, divalent and trivalent chromium co-exist in the slags. It is agreed that the fraction of divalent chromium to total chromium increases with higher temperature, lower slag basicity and oxygen potential. For the slags under oxidising atmosphere, trivalent, pentavalent and hexavalent states were reported to be stable. The activities of CrO and CrO{sub 1.5} were concluded to have positive deviation from ideal solution. Slag basicity has a positive effect and temperature has a negative effect on the activities of chromium oxides. The phase diagrams of the Cr-O, binary, and ternary chromium containing oxide systems have been examined systematically. The analysis shows that the data on the quaternary and quinary systems are insufficient, and require further investigation. The most important features of the chromium containing silicate slags are the large miscibility gaps and the stability of the chromite spinel. (orig.) (76 refs.)
Kinetics of water sorption of damaged bean grains: Thermodynamic properties
Directory of Open Access Journals (Sweden)
Paulo C. Corrêa
Full Text Available ABSTRACT This study aims to determine the thermodynamic properties of damaged beans. Grains with initial moisture content of 53.85% (d.b. were used. A part of the grains was used to obtain the desorption isotherms, while another part was subjected to drying until a moisture content of 5.26% (d.b. was achieved; therefore, it was subjected to the adsorption process. To induce damage, a Stein breakage tester was used. To obtain the equilibrium moisture content, grains were placed in a climatic chamber whose temperatures were 20, 30, 40, and 50 ± 1 °C combined with a relative humidity of 30, 40, 50, 70, and 90 ± 3%. Although in the desorption process, damaged grains had a lower differential enthalpy compared with the control, the reverse behavior was observed in the adsorption process. Mechanical damage caused the formation of a greater number of available adsorption sites, resulting in higher differential entropy values in adsorption and lower values in desorption compared with the control. The mechanical damage had no effect on the Gibbs free energy.
The thermodynamic properties of normal liquid helium 3
Modarres, M.; Moshfegh, H. R.
2009-09-01
The thermodynamic properties of normal liquid helium 3 are calculated by using the lowest order constrained variational (LOCV) method. The Landau Fermi liquid model and Fermi-Dirac distribution function are considered as our statistical model for the uncorrelated quantum fluid picture and the Lennard-Jones and Aziz potentials are used in our truncated cluster expansion (LOCV) to calculate the correlated energy. The single particle energy is treated variationally through an effective mass. The free energy, pressure, entropy, chemical potential and liquid phase diagram as well as the helium 3 specific heat are evaluated, discussed and compared with the corresponding available experimental data. It is found that the critical temperature for the existence of the pure gas phase is about 4.90 K (4.45 K), which is higher than the experimental prediction of 3.3 K, and the helium 3 flashing temperature is around 0.61 K (0.50 K) for the Lennard-Jones (Aziz) potential.
Complexation (cucurbit[6]uril-pyrene): Thermodynamic and spectroscopic properties
Energy Technology Data Exchange (ETDEWEB)
Sueldo Occello, Valeria N.; Rossi, Rita H. de; Veglia, Alicia V., E-mail: aveglia@fcq.unc.edu.ar
2015-02-15
The influence of the macrocyclic compound cucurbit[6]uril (CB6) on the photophysical properties of the fluorophore pyrene (PYR) has been studied. Guest–host interaction was observed by UV–visible spectroscopy and spectrofluorimetry. The fluorescence of PYR was significantly increased in the presence of CB6. The binding equilibrium constants for the complex with 1:1 stoichiometry were determined in HCOOH 55% w/v. The values of the association constants, K{sub A}, and the fluorescence quantum yield ratios between complexed and free substrate, ϕ{sup PYR–CB6}/ϕ{sup PYR}, at different temperatures were (3.1±0.9)×10{sup 2} M{sup −1} and (5.1±0.2), (3.6±0.5)×10{sup 2} M{sup −1} and (5.9±0.1), (4.8±0.7)×10{sup 2} M{sup −1} and (5.5±0.1) at 15.0 °C, 25.0 °C and 40.0 °C, respectively. The enthalpic and entropic contributions to the complexation process were determined, yielding ΔS=(92±3) J mol{sup −1} K{sup −1} and ΔH=(13±1) kJ mol{sup −1}. From these results it can be concluded that the complex formation is mainly driven by the entropic term. The forces involved in the complexation are interpreted from the sign and magnitude of the thermodynamic parameters obtained. The partial inclusion of PYR or the formation of a suspended complex is proposed in base of all the data. The interaction is also demonstrated in the solid state by differential scanning calorimetric (DSC) measurements. - Highlights: • The cucurbit[6]uril (CB6) effects on the absorption and fluorescence of pyrene (PYR) were analyzed. • The association constant (K{sub A}) and the stoichiometry of the complex were determined. • The complex formation was confirmed by differential scanning calorimetry (DSC). • The thermodynamic parameters were determined. • The hydrophobic entropic contribution is the main driving force for the PYR–CB6 complex formation.
Hrubý Jan; Duška Michal
2014-01-01
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 e...
Thermodynamic properties of UF sub 6 measured with a ballistic piston compressor
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.
Magnetic Vortices in Nanodisks: What are the implications in macroscopic magnetic properties?
Gelvez Pedroza, Ciro Fernando; Patino, Edgar J.; Superconductivity; Nanodevices Laboratory Team
The study of nanodevices is of great importance nowadays. In particular nanodisks present extraordinary properties when varying their size, shape and materials. One of the most interesting ones has been the presence of magnetic vortices which are normally not present in continuous films or bulk materials. For that reason, these constitute of great interest in potential applications such as data storage, binary logic gates or nano-plasmonics. Although there are many high cost methods for fabrication we have chosen a low cost technique based on Colloidal Lithography. Using Polystyrene Nanoparticles (100nm) nanodisks of about 180 nm in diameter have been grown using Electron Beam evaporation. The fabrication technique requires a number of steps such as spin coating, oxygen plasma and Ion Beam Etching. The samples obtained with this method were Ti/Co/Nb nanodisks with various thickness of the Co layer. Micromagnetic simulations were carried out in OOMMF giving magnetic domain structure and hysteresis loops which were later compared with those obtained experimentally using Vibrating Sample Magnetometry. Simulation results suggest a critical thickness for the appearance of magnetic vortices, revealed by hysteresis loops with substantially lower coercive fields. Facultad de Ciencias,Vicerrectoria de Investigaciones - Universidad de los Andes.
Mass spectrometric determination of the thermodynamic excess properties of ternary Fe-Co-Cr melts
International Nuclear Information System (INIS)
Schmidt, Harald; Tomiska, Josef
2004-01-01
Computer-aided Knudsen cell mass spectrometry is used for the thermodynamic investigations on ternary Fe-Co-Cr melts over the entire range of composition. The thermodynamic mixing behavior has been determined by means of the 'digital intensity-ratio' (DIR) method. The ternary thermodynamically adapted power (TAP) series concept is used for the algebraic representation of the molar excess properties. The corresponding TAP parameters, and the values of the molar excess quantities Z E (T, x) (Z is the Gibbs energy G, heat of mixing H, entropy S) as well as the thermodynamic activities of all three constituents at 1950 K are presented
Computer codes used in the calculation of high-temperature thermodynamic properties of sodium
International Nuclear Information System (INIS)
Fink, J.K.
1979-12-01
Three computer codes - SODIPROP, NAVAPOR, and NASUPER - were written in order to calculate a self-consistent set of thermodynamic properties for saturated, subcooled, and superheated sodium. These calculations incorporate new critical parameters (temperature, pressure, and density) and recently derived single equations for enthalpy and vapor pressure. The following thermodynamic properties have been calculated in these codes: enthalpy, heat capacity, entropy, vapor pressure, heat of vaporization, density, volumetric thermal expansion coefficient, compressibility, and thermal pressure coefficient. In the code SODIPROP, these properties are calculated for saturated and subcooled liquid sodium. Thermodynamic properties of saturated sodium vapor are calculated in the code NAVAPOR. The code NASUPER calculates thermodynamic properties for super-heated sodium vapor only for low (< 1644 K) temperatures. No calculations were made for the supercritical region
Evolution of the macroscopic properties of two epoxy resins during ageing under irradiation
International Nuclear Information System (INIS)
Vignoud, L.
2001-11-01
In this study, the thermomechanical properties of two epoxy resins (DGEBA/TETA and DGEBA/DDM systems) are analysed as a function of the irradiation dose. The maximum conversion and reticulation is obtained by post-curing treatment. Irradiation by electrons results in a decrease of the glass transition temperature and of the elastic modulus in the rubbery region. These results can be interpreted invoking a destruction of the crosslinks and chains breaks within the resin. The Arrhenius diagrams obtained for the various doses shows that the cooperative mobility associated with the α relaxation becomes faster after the irradiation. On the contrary, more local mobility corresponding to the γ relaxation is also modified, but in a lesser extent. The stress-strain curves are also discussed. In uniaxial compression test, the plastic flow stress σ p decreases when the irradiation dose increases and this effect can largely be accounted for by a variation of T g . Post-irradiative effects are studied in inert atmosphere. Reticulation increases when the material is heated to a higher temperature than its T g . This effect suggest the presence of radical formed during irradiation. For DGEBA/TETA system, glass transition temperature T g shifts towards lowest temperatures. This shift increases the molecular mobility and enhances the physical ageing process at the ambient temperature. The results are well described by the quasi point defects theory. Direct effect of irradiation and physical ageing evolve with the scale parameter t 0 . This parameter characterizes the gap (in time and/or temperature) between the principal relaxation and simplest ones. By connecting t 0 to the amount of irradiation, it is possible to predict the modifications of the behaviour and to predict these evolutions for various amounts. (author)
Electrolytes: transport properties and non-equilibrium thermodynamics
International Nuclear Information System (INIS)
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
Electronic and thermodynamic properties of transition metal elements and compounds
International Nuclear Information System (INIS)
Haeglund, J.
1993-01-01
This thesis focuses on the use of band-structure calculations for studying thermodynamic properties of solids. We discuss 3d-, 4d- and 5d-transition metal carbides and nitrides. Through a detailed comparison between theoretical and experimental results, we draw conclusions on the character of the atomic bonds in these materials. We show how electronic structure calculations can be used to give accurate predictions for bonding energies. Part of the thesis is devoted to the application of the generalized gradient approximation in electronic structure calculations on transition metals. For structures with vibrational disorder, we present a method for calculating averaged phonon frequencies without using empirical information. For magnetic excitations, we show how a combined use of theoretical results and experimental data can yield information on magnetic fluctuations at high temperatures. The main results in the thesis are: Apart for an almost constant shift, theoretically calculated bonding energies for transition metal carbides and nitrides agree with experimental data or with values from analysis of thermochemical information. The electronic spectrum of transition metal carbides and nitrides can be separated into bonding, antibonding and nonbonding electronic states. The lowest enthalpy of formation for substoichiometric vanadium carbide VC 1-X at zero temperature and pressure occurs for a structure containing vacancies (x not equal to 0). The generalized gradient approximation improves theoretical calculated cohesive energies for 3d-transition metals. Magnetic phase transitions are sensitive to the description of exchange-correlation effects in electronic structure calculations. Trends in Debye temperatures can be successfully analysed in electronic structure calculations on disordered lattices. For the elements, there is a clear dependence on the crystal structure (e.g., bcc, fcc or hcp). Chromium has fluctuating local magnetic moments at temperatures well above
Thermodynamic properties and energy characteristics of water+1-propanol
Alhasov, A. B.; Bazaev, A. R.; Bazaev, E. A.; Osmanova, B. K.
2017-11-01
By using own precise experimental data on p,ρ,T,x- relations differential and integral thermodynamic properties of water+1-propanol homogeneous binary mixtures (0.2, 0.5, and 0.8 mole fractions of 1-propanol) were obtained in one phase (liquid, vapor) region, along coexistence curve phase, at critical and supercritical regions of parameters of state. These values were obtained in the regions of temperatures 373.15 - 673.15 K, densities 3 - 820 kg/m3 and pressures up to 50 MPa. It is found that shape of p,ρ,T,- dependences of water+1-propanol mixtures in investigated range of temperatures is the same with those of pure liquid, but the pressure of the mixture is higher than those of pure water or 1-propanol. The critical line of water+1-propanol binary mixtures as opposed to those of water+methanol and water+ethanol mixtures has convex shape. It is ascertained that using water+1-propanol mixture (0.2 mol.fraction of 1-propanol) instead of pure water allows to decrease lower limit of operating temperatures to 50 K, to increase effective coefficient of efficiency and partially unify thermal mechanical equipment of power plant. Our comparative energy analysis of cycles of steam-turbine plant on water and water+1- propanol mixtures, carried out at the same thermobaric conditionsand showed that thermal coefficient of efficiencyofcycle of steam-turbine plant onwater+1-propanol mixture (0.2 mol.fraction of 1-propanol) is higher than those of pure water.Thus and so we made a conclusion about usability of water+1-propanol mixture (0.2 mole fraction of 1-propanol) as a working substance of steam-turbine plant cycle.
International Nuclear Information System (INIS)
Gurvich, L.V.; Bergman, G.A.; Gorokhov, L.N.; Iorish, V.S.; Leonidov, V.Y.; Yungman, V.S.
1997-01-01
The data on thermodynamic and molecular properties of the potassium, rubidium and cesium hydroxides have been collected, critically reviewed, analyzed, and evaluated. Tables of the thermodynamic properties [C p circ , Φ=-(G -H(0)/T, S, H -H(0), Δ f H, Δ f G)] of these hydroxides in the condensed and gaseous states have been calculated using the results of the analysis and some estimated values. The recommendations are compared with earlier evaluations given in the JANAF Thermochemical Tables and Thermodynamic Properties of Individual Substances. The properties considered are: the temperature and enthalpy of phase transitions and fusion, heat capacities, spectroscopic data, structures, bond energies, and enthalpies of formation at 298.15 K. The thermodynamic functions in solid, liquid, and gaseous states are calculated from T=0 to 2000 K for substances in condensed phase and up to 6000 K for gases. copyright 1997 American Institute of Physics and American Chemical Society
Diagram analysis of the Hubbard model: Stationarity property of the thermodynamic potential
International Nuclear Information System (INIS)
Moskalenko, V. A.; Dohotaru, L. A.; Cebotari, I. D.
2010-01-01
The diagram approach proposed many years ago for the strongly correlated Hubbard model is developed with the aim to analyze the thermodynamic potential properties. A new exact relation between renormalized quantities such as the thermodynamic potential, the one-particle propagator, and the correlation function is established. This relation contains an additional integration of the one-particle propagator with respect to an auxiliary constant. The vacuum skeleton diagrams constructed from the irreducible Green's functions and tunneling propagator lines are determined and a special functional is introduced. The properties of this functional are investigated and its relation to the thermodynamic potential is established. The stationarity property of this functional with respect to first-order variations of the correlation function is demonstrated; as a consequence, the stationarity property of the thermodynamic potential is proved.
Directory of Open Access Journals (Sweden)
A. Santos
2013-12-01
Full Text Available Aim of the study: The aim of the study is to assess the variation of pith eccentricity, heartwood proportion, latewood percentage and basic wood density along the stem of 45-year-old A. melanoxylon trees collected in four sites of Portugal, and investigate the eventual relationship between these variables.Area of study: Sites covering littoral north, mid interior north and centre interior of Portugal.Materials and methods: Four sites and five trees per site were selected in the Acacia melanoxylon Portuguese forest.One wood sample at each of six height levels per tree was collected in order to evaluate its basic density, pith eccentricity, heartwood and latewood proportions.Main results: The high variability of the wood macroscopic properties among trees from the same site regarding to the variation of the corresponding average properties along the stem is a key characteristic of the experimental data.As a consequence, a multiple linear regression model tested was not able to properly explain the wood basic density variation of the 120 wood samples analysed. In spite of this, the following trends could be recognized: (i excluding the base level, wood basic density moderately increased with tree level; (ii latewood proportion followed similar behaviour; (iii pith eccentricity was low; (iv heartwood proportion decreased markedly with tree height, from 70% at the base to 7% at the top.Research highlights: The high basic density, the relatively low variability along the stem and the low pith eccentricity enable us to anticipate good performance as raw material for the wood industry.Key words: Acacia melanoxylon; basic density; earlywood; latewood; heartwood; sapwood; pith eccentricity.
Experimental observations related to the thermodynamic properties of tokamak plasmas
International Nuclear Information System (INIS)
Sozzi, C.; Minardi, E.; Lazzaro, E.; Cirant, S.; Mantica, P.; Esposito, B.; Marinucci, M.; Romanelli, M.; Imbeaux, F.
2005-01-01
The coarse-grained tokamak plasma description derived from the magnetic entropy concept presents appealing features as it involves a simple mathematics and it identifies a limited set of characteristic parameters of the macroscopic equilibrium. In this paper a comprehensive review of the work done in order to check the reliability of the Stationary Magnetic Entropy predictions against experimental data collected from different tokamaks, plasma regimes and heating methods is reported. (author)
International Nuclear Information System (INIS)
Sokolovskaya, E.M.; Guzej, L.S.; Tikhankin, G.A.; Meshkov, L.L.
1977-01-01
Thermodynamic properties of solid solutions of niobium and tungsten in nickel have been investigated by the method of electromotive forces with the use of simplex-matrix experiment planning techniques. The planning matrix and the results of investigating the thermodynamic properties of alloys of the nickel-niobium-tungsten system at 1250 deg are presented. The application of experiment planning has made it possible to obtain sufficient information concerning the thermodynamics of solid solutions of niobium and tungsten in nickel from the experimental data for six ternary alloys only
EquilTheTA: Thermodynamic and transport properties of complex equilibrium plasmas
International Nuclear Information System (INIS)
Colonna, G.; D'Angola, A.
2012-01-01
EquilTheTA (EQUILibrium for plasma THErmodynamics and Transport Applications) is a web-based software which calculates chemical equilibrium product concentrations from any set of reactants and determines thermodynamic and transport properties for the product mixture in wide temperature and pressure ranges. The program calculates chemical equilibrium by using a hierarchical approach, thermodynamic properties and transport coefficients starting from recent and accurate databases of atomic and molecular energy levels and collision integrals. In the calculations, Debye length and cut-off are consistently updated and virial corrections (up to third order) can be considered. Transport coefficients are calculated by using high order approximations of the Chapman-Enskog method.
Stability, electronic and thermodynamic properties of aluminene from first-principles calculations
International Nuclear Information System (INIS)
Yuan, Junhui; Yu, Niannian; Xue, Kanhao; Miao, Xiangshui
2017-01-01
Highlights: • We have predicted two NEW stable phases of atomic layer aluminum, buckled and 8-Pmmn aluminene. • We have revealed the electronic structures and bonding characteristics of aluminene. • Thermodynamic properties of aluminene were investigated based on phonon properties. - Abstract: Using first-principles calculations based on density functional theory (DFT), we have investigated the structure stability and electronic properties of both buckled and 8-Pmmn phase aluminene. Phonon dispersion analysis reveals that the buckled and 8-Pmmn aluminene are dynamically stable. The band structure shows that both the buckled and 8-Pmmn aluminene exhibit metallic behavior. Finally, the thermodynamic properties are investigated based on phonon properties.
Stability, electronic and thermodynamic properties of aluminene from first-principles calculations
Energy Technology Data Exchange (ETDEWEB)
Yuan, Junhui [School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); Yu, Niannian [School of Science, Wuhan University of Technology, Wuhan, Hubei 430070 (China); Xue, Kanhao, E-mail: xkh@hust.edu.cn [School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); Miao, Xiangshui [School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China)
2017-07-01
Highlights: • We have predicted two NEW stable phases of atomic layer aluminum, buckled and 8-Pmmn aluminene. • We have revealed the electronic structures and bonding characteristics of aluminene. • Thermodynamic properties of aluminene were investigated based on phonon properties. - Abstract: Using first-principles calculations based on density functional theory (DFT), we have investigated the structure stability and electronic properties of both buckled and 8-Pmmn phase aluminene. Phonon dispersion analysis reveals that the buckled and 8-Pmmn aluminene are dynamically stable. The band structure shows that both the buckled and 8-Pmmn aluminene exhibit metallic behavior. Finally, the thermodynamic properties are investigated based on phonon properties.
Predictions of titanium alloy properties using thermodynamic modeling tools
Zhang, F.; Xie, F.-Y.; Chen, S.-L.; Chang, Y. A.; Furrer, D.; Venkatesh, V.
2005-12-01
Thermodynamic modeling tools have become essential in understanding the effect of alloy chemistry on the final microstructure of a material. Implementation of such tools to improve titanium processing via parameter optimization has resulted in significant cost savings through the elimination of shop/laboratory trials and tests. In this study, a thermodynamic modeling tool developed at CompuTherm, LLC, is being used to predict β transus, phase proportions, phase chemistries, partitioning coefficients, and phase boundaries of multicomponent titanium alloys. This modeling tool includes Pandat, software for multicomponent phase equilibrium calculations, and PanTitanium, a thermodynamic database for titanium alloys. Model predictions are compared with experimental results for one α-β alloy (Ti-64) and two near-β alloys (Ti-17 and Ti-10-2-3). The alloying elements, especially the interstitial elements O, N, H, and C, have been shown to have a significant effect on the β transus temperature, and are discussed in more detail herein.
International Nuclear Information System (INIS)
Du, Jianping; Zhao, Ruihua; Xue, Yongqiang
2012-01-01
Highlights: ► There is an obvious influence of the size on thermodynamic properties for the reaction referring nano-reactants. ► Gibbs function, enthalpy, entropy and equilibrium constant are dependent on the reactant size. ► There is an approximate linear relation between them. - Abstract: The theoretical relations of thermodynamic properties, the equilibrium constant and reactant size in nanosystem are described. The effects of size on thermodynamic properties and the equilibrium constant were studied using nanosize zinc oxide and sodium bisulfate solution as a reaction system. The experimental results indicated that the molar Gibbs free energy, the molar enthalpy and the molar entropy of the reaction decrease, but the equilibrium constant increases with decreasing reactant size. Linear trends were observed between the reciprocal of size for nano-reactant and thermodynamic variable, which are consistent with the theoretical relations.
International Nuclear Information System (INIS)
McKenzie, W.F.
1992-08-01
The thermodynamic properties of secondary phases observed to form during nuclear waste glass-water interactions are of particular interest as it is with the application of these properties together with the thermodynamic properties of other solid phases, fluid phases, and aqueous species that one may predict the environmental consequences of introducing radionuclides contained in the glass into groundwater at a high-level nuclear waste repository. The validation of these predicted consequences can be obtained from laboratory experiments and field observations at natural analogue sites. The purpose of this report is to update and expand the previous compilation (McKenzie, 1991) of thermodynamic data retrieved from the literature and/or estimated for secondary phases observed to form (and candidate phases from observed chemical compositions) during nuclear waste glass-water interactions. In addition, this report includes provisionally recommended thermodynamic data of secondary phases
Nonequilibrium work relation in a macroscopic system
International Nuclear Information System (INIS)
Sughiyama, Yuki; Ohzeki, Masayuki
2013-01-01
We reconsider a well-known relationship between the fluctuation theorem and the second law of thermodynamics by evaluating stochastic evolution of the density field (probability measure valued process). In order to establish a bridge between microscopic and macroscopic behaviors, we must take the thermodynamic limit of a stochastic dynamical system following the standard procedure in statistical mechanics. The thermodynamic path characterizing a dynamical behavior in the macroscopic scale can be formulated as an infimum of the action functional for the stochastic evolution of the density field. In our formulation, the second law of thermodynamics can be derived only by symmetry of the action functional without recourse to the Jarzynski equality. Our formulation leads to a nontrivial nonequilibrium work relation for metastable (quasi-stationary) states, which are peculiar in the macroscopic system. We propose a prescription for computing the free energy for metastable states based on the resultant work relation. (paper)
Thermodynamic properties of a quasi-harmonic model for ferroelectric transitions
International Nuclear Information System (INIS)
Mkam Tchouobiap, S E; Mashiyama, H
2011-01-01
Within a framework of a quasi-harmonic model for quantum particles in a local potential of the double Morse type and within the mean-field approximation for interactions between particles, we investigate the thermodynamic properties of ferroelectric materials. A quantum thermodynamic treatment gives analytic expressions for the internal energy, the entropy, the specific heat, and the static susceptibility. The calculated thermodynamic characteristics are studied as a function of temperature and energy barrier, where it is shown that at the proper choice of the theory parameters, particularly the energy barrier, the model system exhibits characteristic features of either second-order tricritical or first-order phase transitions. Our results indicate that the barrier energy seems to be an important criterion for the character of the structural phase transition. The influence of quantum fluctuations manifested on zero-point energy on the phase transition and thermodynamic properties is analyzed and discussed. This leads to several quantum effects, including the existence of a saturation regime at low temperatures, where the order parameter saturates giving thermodynamic saturation of the calculated thermodynamic quantities. It is found that both quantum effects and energy barrier magnitude have an important influence on the thermodynamic properties of the ferroelectric materials and on driving the phase transition at low temperatures. Also, the analytical parameters' effect on the transition temperature is discussed, which seems to give a general insight into the structural phase transition and its nature.
Symmetry, Optical Properties and Thermodynamics of Neptunium(V Complexes
Directory of Open Access Journals (Sweden)
Linfeng Rao
2009-12-01
Full Text Available 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.
Calculation of thermodynamic properties of finite Bose-Einstein systems
Borrmann, P.; Harting, J.D.R.; Mülken, O.; Hilf, E.
1999-01-01
We derive an exact recursion formula for the calculation of thermodynamic functions of finite systems obeying Bose-Einstein statistics. The formula is applicable for canonical systems where the particles can be treated as noninteracting in some approximation, e.g., like Bose-Einstein condensates in
International Nuclear Information System (INIS)
Salles, F.
2006-10-01
Smectites have interesting properties which make them potential candidates for engineered barriers in deep geological nuclear waste repository: low permeability, swelling and cations retention. The subject of this thesis consists in the determination of the relationship between hydration properties, swelling properties and cations mobility in relation with confinement properties of clayey materials. The aim is to understand and to predict the behaviour of water in smectites, following two research orientations: the mechanistic aspects and the energetic aspects of the hydration of smectites. We worked on the Na-Ca montmorillonite contained in the MX80 bentonite, with the exchanged homo ionic structure (saturated with alkaline cations and calcium cations). The approach crosses the various scales (microscopic, mesoscopic and macroscopic) and implied the study of the various components of the system (layer-cation-water), by using original experimental methods (thermo-poro-metry and electric conductivity for various relative humidities (RH) and electrostatic calculations. Initially, the dry state is defined by SCTA (scanning calorimetry thermal analysis). Then a classical characterization of the smectite porosity for the dry state is carried out using mercury intrusion and nitrogen adsorption. We evidenced the existence of a meso-porosity which radius varies from 2 to 10 nm depending on the compensating cation. The thermo-poro-metry and conductivity experiments performed at various hydration states made it possible to follow the increase in the pore sizes and the cations mobility as a function of the hydration state. We highlight in particular the existence of an osmotic mesoscopic swelling for low RH (approximately 50-60%RH for Li and Na). By combining the results of thermo-poro-metry, X-ray diffraction and electric conductivity, we are able to propose a complete hydration sequence for each cation, showing the crucial role of the compensating cation in the hydration of
Ion-specific thermodynamical properties of aqueous proteins
Directory of Open Access Journals (Sweden)
Eduardo R.A. Lima
2010-03-01
Full Text Available Ion-specific interactions between two colloidal particles are calculated using a modified Poisson-Boltzmann (PBequationandMonteCarlo(MCsimulations. PBequationspresentgoodresultsofionicconcentration profiles around a macroion, especially for salt solutions containing monovalent ions. These equations include not only electrostatic interactions, but also dispersion potentials originated from polarizabilities of ions and proteins. This enables us to predict ion-specific properties of colloidal systems. We compared results obtained from the modified PB equation with those from MC simulations and integral equations. Phase diagrams and osmotic second virial coefficients are also presented for different salt solutions at different pH and ionic strengths, in agreement with the experimental results observed Hofmeister effects. In order to include the water structure and hydration effect, we have used an effective interaction obtained from molecular dynamics of each ion and a hydrophobic surface combined with PB equation. The method has been proved to be efficient and suitable for describing phenomena where the water structure close to the interface plays an essential role. Important thermodynamic properties related to protein aggregation, essential in biotechnology and pharmaceutical industries, can be obtained from the method shown here.Interações íon-específicas (dependentes do tipo de íon presente em solução entre duas partículas coloidais são calculadas usando a equação de Poisson-Boltzmann (PB modificada e simulações de Monte Carlo (MC. As equações de PB apresentam bons resultados de perfis de concentração nas proximidades de um macro-íon, principalmente para soluções salinas contendo íons monovalentes. Estas equações incluem não só interações eletrostáticas, mas também potenciais de dispersão, que têm origem nas polarizabilidades de íons e proteínas, permitindo a predição de propriedades íon-específicas de
International Nuclear Information System (INIS)
Gilles, D.
2005-01-01
This report is devoted to illustrate the power of a Monte Carlo (MC) simulation code to study the thermodynamical properties of a plasma, composed of classical point particles at thermodynamical equilibrium. Such simulations can help us to manage successfully the challenge of taking into account 'exactly' all classical correlations between particles due to density effects, unlike analytical or semi-analytical approaches, often restricted to low dense plasmas. MC simulations results allow to cover, for laser or astrophysical applications, a wide range of thermodynamical conditions from more dense (and correlated) to less dense ones (where potentials are long ranged type). Therefore Yukawa potentials, with a Thomas-Fermi temperature- and density-dependent screening length, are used to describe the effective ion-ion potentials. In this report we present two MC codes ('PDE' and 'PUCE') and applications performed with these codes in different fields (spectroscopy, opacity, equation of state). Some examples of them are discussed and illustrated at the end of the report. (author)
Thermodynamic properties of poly(phenylene-pyridyl) dendrons of the second and the third generations
International Nuclear Information System (INIS)
Smirnova, Natalia N.; Samosudova, Yanina S.; Markin, Alexey V.; Serkova, Elena S.; Kuchkina, Nina V.; Shifrina, Zinaida B.
2017-01-01
Highlights: • We report thermodynamic properties for poly(phenylene-pyridyl) dendrons of the second and the third generations. • The thermodynamic quantities of devitrification and fusion have been determined. • Thermodynamic functions for the temperature range from T → 0 to 520 K for different physical states were calculated. • The dependences of thermodynamic properties of the dendrons on their composition and structure have been obtained. - Abstract: The temperature dependence of the heat capacity of poly(phenylene-pyridyl) dendrons of the second and the third generations have been measured by the method of adiabatic vacuum and differential scanning calorimetry over the range from 6 K to (500–520) K in the present research. Phase transformations have been detected and their thermodynamic characteristics have been estimated and analysed in the above temperature range. The standard thermodynamic functions, namely, the heat capacity C p 0 (T), enthalpy H°(T) − H°(0), entropy S°(T) − S°(0) and potential Φ m °, for the range from T → 0 K to (500–520) K and the standard entropy of formation of the dendrons in different physical states at T = 298.15 K have been calculated based on the experimental results. The thermodynamic characteristics of the samples under study and investigated earlier, poly(phenylene-pyridyl) dendrons decorated with dodecyl groups of the same generations have been compared and discussed.
Nuclear thermodynamics below particle threshold
International Nuclear Information System (INIS)
Schiller, A.; Agvaanluvsan, U.; Algin, E.; Bagheri, A.; Chankova, R.; Guttormsen, M.; Hjorth-Jensen, M.; Rekstad, J.; Siem, S.; Sunde, A. C.; Voinov, A.
2005-01-01
From a starting point of experimentally measured nuclear level densities, we discuss thermodynamical properties of nuclei below the particle emission threshold. Since nuclei are essentially mesoscopic systems, a straightforward generalization of macroscopic ensemble theory often yields unphysical results. A careful critique of traditional thermodynamical concepts reveals problems commonly encountered in mesoscopic systems. One of which is the fact that microcanonical and canonical ensemble theory yield different results, another concerns the introduction of temperature for small, closed systems. Finally, the concept of phase transitions is investigated for mesoscopic systems
Thermodynamic properties of amphiphilic antidepressant drug citalopram HBr
International Nuclear Information System (INIS)
Usman, M.; Khan, A.
2010-01-01
Association characteristics of antidepressant during Citalopram hydrobromide in water Have been examined and its thermodynamic parameters have been calculated using tensiometery and conductometry. The critical micelle concentration (cmc) was determined by surface tension measurement at 30 deg. C and Surface activity was studied by measuring surface parameters i.e. surface pressure, JI, surface excess concentration, area per molecule of drug and standard Gibbs free energy of adsorption, delta G. The electrical conductivity was measured as a function of concentration at various temperatures and cmc was calculated in the temperature range 20-50 deg. C. Thermodynamic parameters i.e. standard free energy of micellization, delta G standard enthalpy of micellization, delta H/sub m/ and standard entropy of micellization, delta S/sub m/ were calculated from cmc value using closed association model. (author)
Thermodynamic properties of uranium in gallium–aluminium based alloys
International Nuclear Information System (INIS)
Volkovich, V.A.; Maltsev, D.S.; Yamshchikov, L.F.; Chukin, A.V.; Smolenski, V.V.; Novoselova, A.V.; Osipenko, A.G.
2015-01-01
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. - Highlights: • Thermodynamics of uranium is determined in Ga–Al alloys of various compositions. • Uranium in the mixed alloys interacts with both components, Ga and Al. • Interaction of U with Al increases with decreasing temperature. • Activity and solubility of uranium depend on Al content in Ga–Al alloys.
Thermodynamic properties of uranium in gallium–aluminium based alloys
Energy Technology Data Exchange (ETDEWEB)
Volkovich, V.A., E-mail: v.a.volkovich@urfu.ru [Department of Rare Metals and Nanomaterials, Institute of Physics and Technology, Ural Federal University, Ekaterinburg, 620002 (Russian Federation); Maltsev, D.S.; Yamshchikov, L.F. [Department of Rare Metals and Nanomaterials, Institute of Physics and Technology, Ural Federal University, Ekaterinburg, 620002 (Russian Federation); Chukin, A.V. [Department of Theoretical Physics and Applied Mathematics, Institute of Physics and Technology, Ural Federal University, Ekaterinburg, 620002 (Russian Federation); Smolenski, V.V.; Novoselova, A.V. [Institute of High-Temperature Electrochemistry UD RAS, Ekaterinburg, 620137 (Russian Federation); Osipenko, A.G. [JSC “State Scientific Centre - Research Institute of Atomic Reactors”, Dimitrovgrad, 433510 (Russian Federation)
2015-10-15
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. - Highlights: • Thermodynamics of uranium is determined in Ga–Al alloys of various compositions. • Uranium in the mixed alloys interacts with both components, Ga and Al. • Interaction of U with Al increases with decreasing temperature. • Activity and solubility of uranium depend on Al content in Ga–Al alloys.
Thermodynamic properties of vitamin B{sub 2}
Energy Technology Data Exchange (ETDEWEB)
Knyazev, A.V., E-mail: knyazevav@gmail.com; Letyanina, I.A.; Plesovskikh, A.S.; Smirnova, N.N.; Knyazeva, S.S.
2014-01-10
Graphical abstract: - Highlights: • Temperature dependence of heat capacity of vitamin B{sub 2} has been measured by precision adiabatic vacuum calorimetry. • The thermodynamic functions of the vitamin B{sub 2} have been determined for the range from T → 0 to 322 K. • The energy of combustion of the riboflavin has been measured at 298.15 K. • The enthalpy of combustion Δ{sub c}H° and the thermodynamic parameters Δ{sub f}H°, Δ{sub f}S°, Δ{sub f}G° have been calculated. - Abstract: In the present work temperature dependence of heat capacity of vitamin B{sub 2} (riboflavin) has been measured for the first time in the range from 6 to 322 K by precision adiabatic vacuum calorimetry. Based on the experimental data, the thermodynamic functions of the vitamin B{sub 2}, namely, the heat capacity, enthalpy H°(T) − H°(0), entropy S°(T) − S°(0) and Gibbs function G°(T) − H°(0) have been determined for the range from T → 0 to 322 K. The value of the fractal dimension D in the function of multifractal generalization of Debye's theory of the heat capacity of solids was estimated and the character of heterodynamics of structure was detected. In a calorimeter with a static bomb and an isothermal shield, the energy of combustion of the riboflavin has been measured at 298.15 K. The enthalpy of combustion Δ{sub c}H° and the thermodynamic parameters Δ{sub f}H°, Δ{sub f}S°, Δ{sub f}G° and of reaction of formation of the riboflavin from simple substances at T = 298.15 K and p = 0.1 MPa have been calculated.
Thermodynamic properties of open noncritical string in external electromagnetic field
International Nuclear Information System (INIS)
Lichtzier, I.M.; Odintsov, S.D.; Bytsenko, A.A.
1991-01-01
We investigate the thermodynamics of open noncritical string (charged and neutral) in an external constant magnetic field. The free energy and Hagedorn temperature are calculated. It is shown that Hagedorn temperature is the same as in the absence of constant magnetic field. We present also the expressions for the free energy and Hagedorn temperature of the neutral open noncritical string in an external constant electromagnetic field. In this case Hagedorn temperature depends on the external electric field. (author)
Czech Academy of Sciences Publication Activity Database
Steiger, Kateřina; Mokrý, P.
2015-01-01
Roč. 24, č. 2 (2015), 025026-025026 ISSN 0964-1726 R&D Projects: GA MŠk(CZ) LO1206; GA ČR GA13-10365S Institutional support: RVO:61389021 Keywords : piezoelectric macro-fiber composite actuator * macroscopic material properties * finite element analysis (FEA) Subject RIV: BI - Acoustics Impact factor: 2.769, year: 2015 http://iopscience.iop.org/0964-1726
Calculation of the thermodynamic properties of liquid Ag–In–Sb alloys
Directory of Open Access Journals (Sweden)
DRAGANA ZIVKOVIC
2006-03-01
Full Text Available The results of calculations of the thermodynamic properties of liquid Ag–In–Sb alloys are presented in this paper. The Redlich–Kister–Muggianu model was used for the calculations. Based on known thermodynamic data for constitutive binary systems and available experimental data for the investigated ternary system, the ternary interaction parameter for the liquid phase in the temperature range 1000–1200 K was determined. Comparison between experimental and calculated results showed their good mutual agreement.
International Nuclear Information System (INIS)
Kritskaya, E.B.; Burylev, B.P.; Mojsov, L.P.; Kritskij, V.E.
2005-01-01
Relaying on the experimentally ascertained linear dependence of the Gibbs excessive mole energies on alkali metal ordinal number in the systems MnBr 2 -MBr (M=Na, K, Rb), thermodynamic properties of the melts in binary systems MBr 2 -M'Br (M'=Li, Cs, Fr) were prepared. Concentration dependences of the Gibbs energies, and thermodynamic activities of compounds in the above systems at 1125 K were calculated [ru
Fluorination effects on the thermodynamic, thermophysical and surface properties of ionic liquids
International Nuclear Information System (INIS)
Vieira, N.S.M.; Luís, A.; Reis, P.M.; Carvalho, P.J.; Lopes-da-Silva, J.A.; Esperança, J.M.S.S.; Araújo, J.M.M.; Rebelo, L.P.N.; Freire, M.G.; Pereiro, A.B.
2016-01-01
Highlights: • Surface tension of fluorinated ionic liquids. • Thermophysical properties of fluorinated ionic liquids. • Thermal properties and thermodynamic functions. - Abstract: This paper reports the thermal, thermodynamic, thermophysical and surface properties of eight ionic liquids with fluorinated alkyl side chain lengths equal or greater than four carbon atoms. Melting and decomposition temperatures were determined together with experimental densities, surface tensions, refractive indices, dynamic viscosities and ionic conductivities in a temperature interval ranging from (293.15 to 353.15) K. The surface properties of these fluorinated ionic liquids were discussed and several thermodynamic functions, as well as critical temperatures, were estimated. Coefficients of isobaric thermal expansion, molecular volumes and free volume effects were calculated from experimental values of density and refractive index and compared with previous data. Finally, Walden plots were used to evaluate the ionicity of the investigated ionic liquids.
International Nuclear Information System (INIS)
Takesue, Shinji
1989-01-01
This is the first part of a series devoted to the study of thermodynamic behavior of large dynamical systems with the use of a family of full-discrete and conservative models named elementary reversible cellular automata (ERCAs). In this paper, basic properties such as conservation laws and phase space structure are investigated in preparation for the later studies. ERCAs are a family of one-dimensional reversible cellular automata having two Boolean variables on each site. Reflection and Boolean conjugation symmetries divide them into 88 equivalence classes. For each rule, additive conserved quantities written in a certain form are regarded as a kind of energy, if they exist. By the aid of the discreteness of the variables, every ERCA satisfies the Liouville theorem or the preservation of phase space volume. Thus, if an energy exists in the above sense, statistical mechanics of the model can formally be constructed. If a locally defined quantity is conserved, however, it prevents the realization of statistical mechanics. The existence of such a quantity is examined for each class and a number of rules which have at least one energy but no local conservation laws are selected as hopeful candidates for the realization of thermodynamic behavior. In addition, the phase space structure of ERCAs is analyzed by enumerating cycles exactly in the phase space for systems of comparatively small sizes. As a result, it is revealed that a finite ERCA is not ergodic, that is, a large number of orbits coexist on an energy surface. It is argued that this fact does not necessarily mean the failure of thermodynamic behavior on the basis of an analogy with the ergodic nature of infinite systems
Thermodynamic properties of liquid mixtures of carbon monoxide and methane
Energy Technology Data Exchange (ETDEWEB)
Calado, J.C.G.; Guedes, H.J.R.; Nunes da Ponte, M.; Streett, W.B.
1984-04-01
Researchers conducted pressure-volume-temperature measurements of liquid methane at -230/sup 0/F and of six liquid mixtures of carbon monoxide and methane at -250/sup 0/, -240/sup 0/, and -230/sup 0/F from just above the saturation vapor pressure to the freezing pressure of methane. The excess volume proved to be large and negative at low pressures but less negative as the pressure increased, being almost zero at the highest pressure. Of the thermodynamic functions, excess enthalpy and excess entropy were much more sensitive to pressure than excess Gibbs energy. Conformal solution theory in the van der Waals one-fluid form reproduced the experimental results very successfully.
Macroscopic balance model for wave rotors
Welch, Gerard E.
1996-01-01
A mathematical model for multi-port wave rotors is described. The wave processes that effect energy exchange within the rotor passage are modeled using one-dimensional gas dynamics. Macroscopic mass and energy balances relate volume-averaged thermodynamic properties in the rotor passage control volume to the mass, momentum, and energy fluxes at the ports. Loss models account for entropy production in boundary layers and in separating flows caused by blade-blockage, incidence, and gradual opening and closing of rotor passages. The mathematical model provides a basis for predicting design-point wave rotor performance, port timing, and machine size. Model predictions are evaluated through comparisons with CFD calculations and three-port wave rotor experimental data. A four-port wave rotor design example is provided to demonstrate model applicability. The modeling approach is amenable to wave rotor optimization studies and rapid assessment of the trade-offs associated with integrating wave rotors into gas turbine engine systems.
Thermodynamic properties of 4-tert-butyl-diphenyl oxide
International Nuclear Information System (INIS)
Druzhinina, A.I.; Pimenova, S.M.; Tarazanov, S.V.; Nesterova, T.N.; Varushchenko, R.M.
2015-01-01
Highlights: • The sample of the 4-tert-butyl-diphenyl oxide was synthesized and purified. • Heat capacities, energy of combustion, saturation vapor pressures were measured. • The temperature, the enthalpy and the entropy of fusion were determined. • The enthalpy of sublimation at T = 298.15 K was derived. • The main thermodynamic functions and functions of formation were computed. - Abstract: The main thermodynamic functions (changes of the entropy, enthalpy, and Gibbs free energy) and functions of formation at T = 298.15 K of 4-tert-butyl-diphenyl oxide in condensed and ideal gas states were computed on the basis of experimental results obtained. The heat capacities of 4-tert-butyl-diphenyl oxide was measured by vacuum adiabatic calorimetry over the temperature range (8 to 371) K. The temperature, the enthalpy and the entropy of fusion were determined. The energy of combustion of the sample was determined by static-bomb combustion calorimetry. The saturation vapor pressures of the substance were measured by dynamic transpiration method over the temperature and pressure intervals (298 to 325) K and (0.05 to 1.2) Pa. The enthalpy of sublimation at T = 298.15 K was derived. The contribution of O-(2C b ) group (where C b is the carbon atom in a benzene ring) into the absolute entropies of diphenyl oxide derivatives was assessed
Experimental verification of the thermodynamic properties for a jet-A fuel
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.
International Nuclear Information System (INIS)
Dubovitskii, V.A.; Pavlov, G.A.; Krasnikov, Yu.G.
1996-01-01
Thermodynamic analysis of media with strong interparticle (Coulomb) interaction is presented. A method for constructing isotherms is proposed for a medium described by a closed multicomponent thermodynamic model. The method is based on choosing an appropriate nondegenerate frame of reference in the extended space of thermodynamic variables and provides efficient thermodynamic calculations in a wide range of parameters, for an investigation of phase transitions of the first kind, and for determining both the number of phases and coexistence curves. A number of approximate thermodynamic models of hydrogen plasma are discussed. The approximation corresponding to the n5/2 law, in which the effects of particle attraction and repulsion are taken into account qualitatively, is studied. This approximation allows studies of thermodynamic properties of a substance for a wide range of parameters. In this approximation, for hydrogen at a constant temperature, various properties of the degree of ionization are revealed. In addition, the parameters of the second critical point are found under conditions corresponding to the Jovian interior
Energy Technology Data Exchange (ETDEWEB)
Tong Bo [Thermochemistry Laboratory, Dalian Institute of Chemical physics, Chinese Academy of Sciences, Dalian 116023 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100049 (China); Tan Zhicheng [Thermochemistry Laboratory, Dalian Institute of Chemical physics, Chinese Academy of Sciences, Dalian 116023 (China) and College of Environmental Science and Engineering, Dalian Jiaotong University, Dalian 116028 (China)]. E-mail: tzc@dicp.ac.cn; Shi Quan [Thermochemistry Laboratory, Dalian Institute of Chemical physics, Chinese Academy of Sciences, Dalian 116023 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100049 (China); Li Yansheng [College of Environmental Science and Engineering, Dalian Jiaotong University, Dalian 116028 (China); Yue Danting [Thermochemistry Laboratory, Dalian Institute of Chemical physics, Chinese Academy of Sciences, Dalian 116023 (China); Wang Shaoxu [College of Environmental Science and Engineering, Dalian Jiaotong University, Dalian 116028 (China)
2007-06-15
The low-temperature heat capacity C{sub p,m}{sup 0} of xylitol was precisely measured in the temperature range from 80 to 390K by means of a small sample automated adiabatic calorimeter. A solid-liquid phase transition was found from the experimental C{sub p}-T curve in the temperature range 360-375K with the peak heat capacity at 369.04K. The dependence of heat capacity on the temperature was fitted to the following polynomial equations with least square method. In the temperature range of 80-360K, C{sub p,m}{sup 0}(JK{sup -1}mol{sup -1})=165.87+105.19x+1.8011x{sup 2}-41.445x{sup 3}-41.851x{sup 4}+65.152x{sup =} 5+66.744x{sup 6},x=[T(K)-220]/140. In the temperature range of 370-390K, C{sub p,m}{sup 0}(JK{sup -1}mol{sup -1})=426.19+5.6366x,x=[T(K)-380]/10. The molar enthalpy and entropy of this transition were determined to be 33.26+/-0.17kJmol{sup -1} and 90.12+/-0.45JK{sup -1}mol{sup -1}, respectively. The standard thermodynamic functions (H{sub T}{sup 0}-H{sub 298.15}{sup 0}) and (S{sub T}{sup 0}-S{sub 298.15}{sup 0}), were derived from the heat capacity data in the temperature range of 80 to 390K with an interval of 5K. The standard molar enthalpy of combustion and the standard molar enthalpy of formation of the compound have been determined, {delta}{sub c}H{sub m}{sup 0} (C{sub 5}H{sub 12}O{sub 5}, cr)=(-2463.2+/-1.2)kJmol{sup -1}and {delta}{sub f}H{sub m}{sup 0} (C{sub 5}H{sub 12}O{sub 5}, cr)=(-1219.3+/-0.3)kJmol{sup -1}, by means of a precision oxygen bomb combustion calorimeter at T=298.15K. DSC and TG measurements were performed to study the thermal stability of the compound. The results were in agreement with those obtained from heat capacity measurements.
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.
Directory of Open Access Journals (Sweden)
Hrubý Jan
2014-03-01
Full Text Available 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.
Dynamic and Thermodynamic Properties of a CA Engine with Non-Instantaneous Adiabats
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Ricardo T. Paéz-Hernández
2017-11-01
Full Text Available This paper presents an analysis of a Curzon and Alhborn thermal engine model where both internal irreversibilities and non-instantaneous adiabatic branches are considered, operating with maximum ecological function and maximum power output regimes. Its thermodynamic properties are shown, and an analysis of its local dynamic stability is performed. The results derived are compared throughout the work with the results obtained previously for a case in which the adiabatic branches were assumed as instantaneous. The results indicate a better performance for thermodynamic properties in the model with instantaneous adiabatic branches, whereas there is an improvement in robustness in the case where non-instantaneous adiabatic branches are considered.
Thermodynamic and dynamical properties of dense ICF plasma
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Gabdullin Maratbek T.
2016-06-01
Full Text Available In present work, thermodynamic expressions were obtained through potentials that took into consideration long-range many-particle screening effects as well as short-range quantum-mechanical effects and radial distribution functions (RDFs. Stopping power of the projectile ions in dense, non-isothermal plasma was considered. One of the important values that describe the stopping power of the ions in plasma is the Coulomb logarithm. We investigated the stopping power of ions in inertial confinement fusion (ICF plasma and other energetic characteristics of fuel. Calculations of ions energy losses in the plasma for different values of the temperature and plasma density were carried out. A comparison of the calculated data of ion stopping power and energy deposition with experimental and theoretical results of other authors was also performed.
Thermodynamic properties of cyclohexanamines: Experimental and theoretical study
International Nuclear Information System (INIS)
Verevkin, Sergey P.; Emeĺyanenko, Vladimir N.
2015-01-01
Highlights: • Vapor pressures of four cyclohexanamine derivatives were measured. • Vaporization enthalpies were derived and compared with the literature. • Thermochemical data tested for consistency using additivity rules and computations. • Contradiction between available liquid phase enthalpies of formation was resolved. • Strength of intra-molecular hydrogen bonding in cyclohexyl-1,2-diamines assessed. - Abstract: Vapor pressures of cyclohexanamine, N-methyl-cyclohexanamine, N,N-dimethyl-cyclohexanamine, and N-cyclohexyl-cyclohexanamine were measured using the transpiration method. Molar enthalpies of vaporization of cyclohexanamine derivatives were derived from vapor pressure temperature dependences. Thermodynamic data on cyclohexanamine derivatives available in the literature were collected and treated uniformly. Consistency of the experimental data was proved with a group- contribution method and quantum-chemical calculations. Evaluated vaporization and formation enthalpies of cyclohexanamine derivatives were recommended for practical thermochemical calculations
Thermodynamic properties of 3He--4He mixtures near Tlambda
International Nuclear Information System (INIS)
Kakizaki, A.; Satoh, T.
1976-01-01
In order to investigate 3 He impurity effects on the superfluid transition, measurements were made on the thermodynamic quantities, specific heat, thermal expansion coefficients, and pressure dependence of the lambda-transition temperature of three 3 He-- 4 He mixtures and pure 4 He in the neighborhood of the lambda-transition temperature under their saturated vapor pressure. Making use of these measured quantities, it is shown that the so-called Pippard--Buckingham--Fairbank relation holds for 3 He-- 4 He mixtures as well as for pure 4 He, at least in the temperature region of 10 -4 K less than or equal to absolute value (T - T/sub lambda/) less than or equal to 10 -2 K. Based on this, the 3 He impurity effects on the behavior of the specific heat near the lambda-transition are discussed
Thermodynamic properties of rotating trapped ideal Bose gases
International Nuclear Information System (INIS)
Li, Yushan; Gu, Qiang
2014-01-01
Ultracold atomic gases can be spined up either by confining them in rotating frame, or by introducing “synthetic” magnetic field. In this paper, thermodynamics of rotating ideal Bose gases are investigated within truncated-summation approach which keeps to take into account the discrete nature of energy levels, rather than to approximate the summation over single-particle energy levels by an integral as it does in semi-classical approximation. Our results show that Bose gases in rotating frame exhibit much stronger dependence on rotation frequency than those in “synthetic” magnetic field. Consequently, BEC can be more easily suppressed in rotating frame than in “synthetic” magnetic field.
Thermodynamic properties of some metal oxide-zirconia systems
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.
Energy Technology Data Exchange (ETDEWEB)
Guencheva, V.; Grantscharova, E.; Gutzow, I. [Bulgarian Academy of Sciences, Sofia (Bulgaria). Inst. of Physical Chemistry
2001-07-01
The temperature dependencies of the thermodynamic properties of the little known (or even hypothetical) undercooled carbon melt and of the glasses that could be obtained from it at appropriate cooling rates are constructed. This is done using both a general thermodynamic formalism to estimate equilibrium properties of undercooled glass-forming melts and the expected analogy in properties of Fourth Group Elements. A comparison of the hypothetical carbon glasses with amorphous materials, obtained by the pyrolisis of organic resins, usually called vitreous (or glassy) carbon, is made. It turns out that from a thermodynamic point of view existing vitreous carbon materials, although characterized by an amorphous, frozen-in structure, differ significantly from the carbon glasses, which could be obtained by a splat-cool-quench of the carbon melt. It is shown also that the hypothetical carbon glasses should have at any temperature a thermodynamic potential, significantly higher than that of diamond. Thus they could be used as a source of constant supersaturation in metastable diamond synthesis. Existing amorphous carbon materials, although showing considerably lower thermodynamic potentials than the hypothetical carbon glasses, could also be used as sources of constant supersaturation in a process of isothermal diamond synthesis if their thermodynamic potential is additionally increased (e.g. by mechano-chemical treatment or by dispersion into nano-size scale). Theoretical estimates made in terms of Ostwald's Rule of Stages indicate that in processes of metastable isothermal diamond synthesis additional kinetic factors (e.g. influencing the formation of sp{sup 3} - carbon structures in the ambient phase) and the introduction of active substrates (e.g. diamond powder) are to be of significance in the realization of this thermodynamic possibility. (orig.)
International Nuclear Information System (INIS)
Fraser, D.G.; Refson, K.
1992-01-01
The molecular dynamics calculations reported above give calculated P-V-T properties for H 2 O up to 1500 K and 100 GPa, which agree remarkably well with the available experimental data. We also observe the phase transition to a crystalline, orientationally disordered cubic ice structure. No account was taken of molecular flexibility in these calculations nor of potential dissociation at high pressures as suggested by Hamman (1981). However, we note that the closest next-nearest-neighbour O-H approach remains significantly greater than the TIP4P fixed O-H bond length within the water molecule for all pressures studied. The equation of state proposed here should be useful for estimating the properties of H 2 O at up to 1500 K and 100 G Pa (1 Mbar) and is much easier to use in practice than modified Redlich Kwong equations. Extension of these methods to the studies of other fluids and of fluid mixtures at high temperatures and pressures will require good potential models for the species involved, and this is likely to involve a combination of good ab initio work and semiempirical modelling. Once developed, these models should allow robust predictions of thermodynamic properties beyond the range of the experimental data on the basis of fundamental molecular information
Reduction of tungstates and molybdates by hydrogen and thermodynamic properties of these salts
International Nuclear Information System (INIS)
Gerasimov, Ya.I.; Rezukhina, T.N.; Simanov, Yu.P.; Vasil'eva, I.A.; Kurshakova, R.D.
1988-01-01
Study of thermodynamic properties of a series of tungstates of bivalent metals (Mg, Ca, Sr, Ba, Mn, Co, Fe, Ni, Cu, Zn, Cd and Pb) as well as of some molybdates- of Mg, Ca, Sr, Ba is carried out. The obtained values are compared with magnetic characteristics of compounds and parameters of their crystal lattices. Thermodynamic properties were studied by measuring constants of their reduction with hydrogen in the 500-1350 deg C temperature range. It is concluded that dependence of thermodynamic values on geometric parameters of the lattice is not definitive. Comparison of salt formation atomic entropies with deviations of salt magnetic moments from theoretical ionic moments points to the fact of existence of some accordance between these two series of values. 25 refs.; 10 figs.; 6 tabs
Generalization of first-principles thermodynamic model: Application to hexagonal close-packed ε-Fe3N
DEFF Research Database (Denmark)
Bakkedal, Morten B.; Shang, Shu- Li; Liu, Zi-Kui
2016-01-01
A complete first-principles thermodynamic model was developed and applied to hexagonal close-packed structure ε-Fe3N. The electronic structure was calculated using density functional theory and the quasiharmonic phonon approximation to determine macroscopic thermodynamic properties at finite...
D-Dimensional ideal gas in parastatistics.: thermodynamic properties
International Nuclear Information System (INIS)
Sousa Vieira, M. C. de; Tsallis, C.
1986-01-01
A parastatistics ideal gas with energy spectrum ε is proportional to |k| → sup (α) (α>0) or even more general in a d-dimensional box with volume V (periodic boundary conditions), the number N of the gas particles being well determined (real particles) or not (quasi particles), is considered. The main thermodynamic quantities (chemical potential, internal energy, specific heat C, equation of state, latent heat, average numbers of particles) for arbitrary d,α, T (temperature) and p (maximal number of particles per state allowed in the parastatistics), are calculated. The main asymptotic regimes are worked out explicitly. In particular, the Bose-Einstein condensation for fixed density, N/V appears as a non uniform convergence in the p→ ∞ limit, in complete analogy with the standard critical phenomena which appear in interacting systems in the N →∞ limit. The system behaves essentially like a Fermi-Dirac one for all finite values of p, and reveals a Bose-Einstein behavior only in the p → ∞ limit. For instance, at low temperatures C ∝ T if p d/α if p → ∞. Finally the Sommerfeld integral and its expansion are generalized to an arbitrary finite p. (author) [pt
Mean-field potential approach for thermodynamic properties of lanthanide: Europium as a prototype
Kumar, Priyank; Bhatt, N. K.; Vyas, P. R.; Gohel, V. B.
2018-03-01
In the present paper, a simple conjunction scheme [mean-field potential (MFP) + local pseudopotential] is used to study the thermodynamic properties of divalent lanthanide europium (Eu) at extreme environment. Present study has been carried out due to the fact that divalent nature of Eu arises because of stable half-filled 4f-shell at ambient condition, which has great influence on the thermodynamic properties at extreme environment. Due to such electronic structure, it is different from remaining lanthanides having incomplete 4f-shell. The presently computed results of thermodynamic properties of Eu are in good agreement with the experimental results. Looking to such success, it seems that the concept of MFP approach is successful to account contribution due to nuclear motion to the total Helmholtz free energy at finite temperatures and pressure-induced inter-band transfer of electrons for condensed state of matter. The local pseudopotential is used to evaluate cold energy and hence MFP accounts the s-p-d-f hybridization properly. Looking to the reliability and transferability along with its computational and conceptual simplicity, we would like to extend the present scheme for the study of thermodynamic properties of remaining lanthanides and actinides at extreme environment.
Modelling of physical and thermodynamic properties in systems containing edible oils and biodiesel
DEFF Research Database (Denmark)
Cunico, Larissa; Ceriani, Roberta; Sarup, Bent
The knowledge of physical and thermodynamic properties of pure components and their mixtures is a basic requirement for performing tasks related to process design, simulation, and optimization and also for performing chemical product design using computer aided molecular/mixture design (CAMD) too...
REMC Computer Simulation of the Thermodynamic Properties of Argon and Air Plasmas
Czech Academy of Sciences Publication Activity Database
Lísal, Martin; Smith, W. R.; Bureš, M.; Vacek, V.; Navrátil, J.
2002-01-01
Roč. 100, č. 15 (2002), s. 2487-2497 ISSN 0026-8976 R&D Projects: GA ČR GA203/98/1446; GA ČR GA203/02/0805 Grant - others:NSERC(CA) OGP1041 Keywords : computer simulation * plasma * thermodynamic properties Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.617, year: 2002
Behavior of the Thermodynamic Properties of Binary Mixtures near the Critical Azeotrope
Directory of Open Access Journals (Sweden)
Azzedine Abbaci
2003-12-01
Full Text Available Abstract: In this work we investigate the critical line of binary azeotropic mixtures of acetone-n-pentane. We pinpoint the abnormal behavior of the critical density line as a function of the mole fraction of one of the component and show its influence on other thermodynamic properties such as the volume, the enthalpy and the entropy.
Mechanical, thermodynamic and electronic properties of wurtzite and zinc-blende GaN crystals
Qin, Hongbo; Luan, Xinghe; Feng, Chuang; Yang, Daoguo; Zhang, G.Q.
2017-01-01
For the limitation of experimental methods in crystal characterization, in this study, the mechanical, thermodynamic and electronic properties of wurtzite and zinc-blende GaN crystals were investigated by first-principles calculations based on density functional theory. Firstly, bulk moduli,
Elements of statistical thermodynamics
Nash, Leonard K
2006-01-01
Encompassing essentially all aspects of statistical mechanics that appear in undergraduate texts, this concise, elementary treatment shows how an atomic-molecular perspective yields new insights into macroscopic thermodynamics. 1974 edition.
A theoretical prediction of thermodynamic properties of chlorine fluorides
International Nuclear Information System (INIS)
Du, Hongchen; Liu, Yan; Wang, Fang; Zhang, Jianying; Liu, Hui; Gong, Xuedong
2011-01-01
Graphical abstract: Correlation between the HOFs obtained from the formation reactions (HOF(FR)) and modified formation reactions (HOF(MFR)). Highlights: → We calculate the heats of formation of nine chlorine fluorides - ClF, ClF 3 , ClF 5 , ClFO, ClFO 2 , ClFO 3 , ClF 3 O 2 , ClF 3 O, and ClF 5 O. → The formation reaction in conjunction with the G3 theory can give accurate results. → ClF, ClF 3 , ClF 5 and ClF 3 O are stable at the room temperature. → ClFO 2 , ClF 3 O 2 and ClF 5 O may be stable at lower temperature. - Abstract: The heats of formation of ClF, ClF 3 , ClF 5 , ClFO, ClFO 2 , ClFO 3 , ClF 3 O 2 , ClF 3 O, and ClF 5 O have been calculated with the help of atomization reaction (AR), formation reaction (FR), and modified formation reaction (MFR) at the G3 and G3X (X = B3, MP2, and MP2B3) levels. FR or MFR in conjunction with the G3 theory can give accurate results close to experimental values. The standard thermodynamic functions of the title compounds have also been evaluated and the results agree well with the available experimental data. Results show that ClF, ClF 3 , ClF 5 and ClF 3 O are stable at the room temperature, and ClFO 2 , ClF 3 O 2 , and ClF 5 O may be stable at lower temperature.
Thermodynamics of urban population flows.
Hernando, A; Plastino, A
2012-12-01
Orderliness, reflected via mathematical laws, is encountered in different frameworks involving social groups. Here we show that a thermodynamics can be constructed that macroscopically describes urban population flows. Microscopic dynamic equations and simulations with random walkers underlie the macroscopic approach. Our results might be regarded, via suitable analogies, as a step towards building an explicit social thermodynamics.
Determination of the thermodynamic properties of water from the speed of sound
International Nuclear Information System (INIS)
Trusler, J.P. Martin; Lemmon, Eric W.
2017-01-01
Highlights: • We analyse error propagation in thermodynamic integration of fluid-phase sound speed data. • A new correlation of the speed of sound in liquid water is derived. • Thermodynamic integration is carried out for pure water. • Derived properties considered include density, isobaric expansivity and isobaric specific heat capacity. - Abstract: Thermodynamic properties of compressed liquids may be obtained from measurements of the speed of sound by means of thermodynamic integration subject to initial values of density and isobaric specific heat capacity along a single low-pressure isobar. In this paper, we present an analysis of the errors in the derived properties arising from perturbations in both the speed-of-sound surface and the initial values. These errors are described in first order by a pair of partial differential equations that we integrate for the example case of water with various scenarios for the errors in the sound speed and the initial values. The analysis shows that errors in either the speed of sound or the initial values of density that are rapidly oscillating functions of temperature have a disproportionately large influence on the derived properties, especially at low temperatures. In view of this, we have obtained a more accurate empirical representation of the recent experimental speed-of-sound data for water [Lin and Trusler, J. Chem. Phys. 136, (2012) 094511] and use this in a new thermodynamic integration to obtain derived properties including density, isobaric heat capacity and isobaric thermal expansivity at temperatures between (253.15 and 473.15) K at pressures up to 400 MPa. The densities obtained in this way are in very close agreement with those reported by Lin and Trusler, but the isobaric specific heat capacity and the isobaric expansivity both differ significantly in the extremes of low temperatures and high pressures.
Belov, G. V.; Dyachkov, S. A.; Levashov, P. R.; Lomonosov, I. V.; Minakov, D. V.; Morozov, I. V.; Sineva, M. A.; Smirnov, V. N.
2018-01-01
The database structure, main features and user interface of an IVTANTHERMO-Online system are reviewed. This system continues the series of the IVTANTHERMO packages developed in JIHT RAS. It includes the database for thermodynamic properties of individual substances and related software for analysis of experimental results, data fitting, calculation and estimation of thermodynamical functions and thermochemistry quantities. In contrast to the previous IVTANTHERMO versions it has a new extensible database design, the client-server architecture, a user-friendly web interface with a number of new features for online and offline data processing.
Thermodynamics properties of lanthanide series near melting point-A pseudopotential approach
Suthar, P. H.; Gajjar, P. N.
2018-04-01
The present paper deals with computational study of thermodynamics properties for fifteen elements of lanthanide series. The Helmholtz free energy (F), Internal energy (E) and Entropy (S)have been computed using variational method based on the Gibbs-Bogoliubov (GB) along with Percus-Yevick hard sphere reference system and Gajjar's model potential. The local field correction function proposed by Taylor is applied to introduce the exchange and correlation effects in the study of thermodynamics of these metals. The present results in comparison with available theoretical and experimental are found to be in good agreement and confirm the ability of the model potential.
Directory of Open Access Journals (Sweden)
Hammou Amine Bouziane
2013-03-01
Full Text Available We study the thermodynamic and structural properties of a flexible homopolymer chain using both multi canonical Monte Carlo method and Wang-Landau method. In this work, we focus on the coil-globule transition. Starting from a completely random chain, we have obtained a globule for different sizes of the chain. The implementation of these advanced Monte Carlo methods allowed us to obtain a flat histogram in energy space and calculate various thermodynamic quantities such as the density of states, the free energy and the specific heat. Structural quantities such as the radius of gyration where also calculated.
International Nuclear Information System (INIS)
Ackermann, R.J.; Rauh, E.G.
1977-01-01
The thermodynamic properties of the lanthanide and actinide oxides are examined, compared, and associated with a variety of high temperature chemical behavior. Trends are cited resulting from a number of thermodynamic and spectroscopic correlations involving solid phases, species in aqueous solution, and molecules and ions in the vapor phase. Inadequacies in the data and alternative approaches are discussed. The characterization of nonstoichiometric phases stable only at high temperatures is related to a network of heterogeneous and homogeneous equilibria. A broad perspective of similarity and dissimilarity between the lanthanides and actinides emerges and forms the basis of the projected needs for further study
Thermodynamic properties of an extremely rapid protein folding reaction.
Schindler, T; Schmid, F X
1996-12-24
The cold-shock protein CspB from Bacillus subtilis is a very small beta-barrel protein, which folds with a time constant of 1 ms (at 25 degrees C) in a U reversible N two-state reaction. To elucidate the energetics of this extremely fast reaction we investigated the folding kinetics of CspB as a function of both temperature and denaturant concentration between 2 and 45 degrees C and between 1 and 8 M urea. Under all these conditions unfolding and refolding were reversible monoexponential reactions. By using transition state theory, data from 327 kinetic curves were jointly analyzed to determine the thermodynamic activation parameters delta H H2O++, delta S H2O++, delta G H2O++, and delta C p H2O++ for unfolding and refolding and their dependences on the urea concentration. 90% of the total change in heat capacity and 96% of the change in the m value (m = d delta G/d[urea]) occur between the unfolded state and the activated state. This suggests that for CspB the activated state of folding is unusually well structured and almost equivalent to the native protein in its interactions with the solvent. As a consequence of this native-like activated state a strong temperature-dependent enthalpy/entropy compensation is observed for the refolding kinetics, and the barrier to refolding shifts from being largely enthalpic at low temperature to largely entropic at high temperature. This shift originates not from the changes in the folding protein chains itself, but from the changes in the protein-solvent interactions. We speculate that the absence of intermediates and the native-like activated state in the folding of CspB are correlated with the small size and the structural type of this protein. The stabilization of a small beta-sheet as in CspB requires extensive non-local interactions, and therefore incomplete sheets are unstable. As a consequence, the critical activated state is reached only very late in folding. The instability of partially folded structure is a means to
Thermodynamic Properties of Alloys of Iron and Silicon
International Nuclear Information System (INIS)
Vecher, R.A.; Gejderih, V.A.; Gerasimov, Ja.I.
1966-01-01
The Fe-Si phase diagram is complex. At 1000°K there are FeSi 2 (β) and FeSi phases and solid solutions of silicon in α and α' iron. EMF measurements were made on the electrochemical cells: Fe|Fe 2+ , KI + Nal|Fe-Si at 600-800°C molten The alloys were prepared from particularly pure components by powder metallurgy and protracted annealing. Studies were made of ten alloys with silicon content between 85 and 4% in all the phase fields in the diagram section at 1000°K. We calculated the integral thermodynamic quantities ΔG, ΔH and ΔS for the formation of the silicides FeSi 2 (β), FeSi and Fe 3 Si at the mean temperature for the experimental range (1000°K), and also (using the thermal capacity of the silicides, the iron and the silicon) at 298, 1188 and 1798°K. The heats of formation of the silicides mentioned at 298°K (kcal/mole) are -19.4, -17.6 and -22.4 respectively. The data existing in the literature enable us to calculate the heat of formation of FeSi 2.33 (α-leboite) at 298°K and this is found to be -14.4 kcal/mole. The heats calculated by us are 1.5-3 kcal higher than the experimental values of Corber and Olsen. The heats of mixing calculated by us for liquid alloys agree well with data in the literature. The data obtained can be regarded as due to the change in the character of the bond in silicides from metallic to covalent when the silicon content is increased. From the data for alloy solutions of silicon in a-iron, the iron activities were calculated. It was found that the α ⇌ α' transformation observed is a real phase transformation. The two-phase range is wider than shown in the phase diagram (from data in the literature). Conversion of the iron activities in solid solution to liquid solution gives good agreement with the data of Chipman. (author) [fr
International Nuclear Information System (INIS)
Manes, L.; Mari, C.; Ray, I.
1979-01-01
The tetrahedral defect consisting of one oxygen vacancy bonded to two reduced cations - is an important concept, which, as shown in the present work, can explain both the thermodynamic properties and the structures of the phases of the PuO 2 -x and CeO 2 -x systems. Based on this concept a statistical thermodynamic model has been developed and this model is described along with some preliminary calculations. A relatively good agreement with experimental thermodynamic data was obtained in this calculation. Using the exclusion principle, defect complexes each containing one tetrahedral defect are derived and it is shown that a systematic packing of these gives a good description both of the non-stoichiometric and the ordered phases observed for these oxide systems. (orig.) [de
International Nuclear Information System (INIS)
Noh, Seunghyo; Kwak, Dohyun; Lee, Juseung; Kang, Joonhee; Han, Byungchan
2014-01-01
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.
Thermodynamic properties of water in confined environments: a Monte Carlo study
Gladovic, Martin; Bren, Urban; Urbic, Tomaž
2018-05-01
Monte Carlo simulations of Mercedes-Benz water in a crowded environment were performed. The simulated systems are representative of both composite, porous or sintered materials and living cells with typical matrix packings. We studied the influence of overall temperature as well as the density and size of matrix particles on water density, particle distributions, hydrogen bond formation and thermodynamic quantities. Interestingly, temperature and space occupancy of matrix exhibit a similar effect on water properties following the competition between the kinetic and the potential energy of the system, whereby temperature increases the kinetic and matrix packing decreases the potential contribution. A novel thermodynamic decomposition approach was applied to gain insight into individual contributions of different types of inter-particle interactions. This decomposition proved to be useful and in good agreement with the total thermodynamic quantities especially at higher temperatures and matrix packings, where higher-order potential-energy mixing terms lose their importance.
Macroscopic proof of the Jarzynski–Wójcik fluctuation theorem for heat exchange
International Nuclear Information System (INIS)
Sughiyama, Yuki; Abe, Sumiyoshi
2008-01-01
In a recent work, Jarzynski and Wójcik (2004 Phys. Rev. Lett. 92 230602) have shown by using the properties of Hamiltonian dynamics and a statistical mechanical consideration that heat exchange through contact between two systems initially prepared at different temperatures obeys a fluctuation theorem. Here, another proof is presented, in which only macroscopic thermodynamic quantities are employed. The detailed balance condition is found to play an essential role. As a result, the theorem is found to hold under very general conditions
Ideal-gas thermodynamic properties for natural-gas applications
International Nuclear Information System (INIS)
Jaeschke, M.; Schley, P.
1995-01-01
Calculating caloric properties from a thermal equation of state requires information such as isobaric heat capacities in the ideal-gas state as a function of temperature. In this work, values for the parameters of the c p o correlation proposed by Aly and Lee were newly determined for 21 pure gases which are compounds of natural gas mixtures. The values of the parameters were adjusted to selected c p o data calculated form spectroscopic data for temperatures ranging from 10 to 1000 K. The data sources used are discussed and compared with literature data deduced from theoretic models and caloric measurements. The parameters presented will be applied in a current GERG project for evaluating equations of state (e.g., the AGA 8 equation) for their suitability for calculating caloric properties
On quantum mechanics for macroscopic systems
International Nuclear Information System (INIS)
Primas, H.
1992-01-01
The parable of Schroedinger's cat may lead to several up-to date questions: how to treat open systems in quantum theory, how to treat thermodynamically irreversible processes in the quantum mechanics framework, how to explain, following the quantum theory, the existence, phenomenologically evident, of classical observables, what implies the predicted existence by the quantum theory of non localized macroscopic material object ?
Thermodynamic and mechanical properties of TiC from ab initio calculation
International Nuclear Information System (INIS)
Dang, D. Y.; Fan, J. L.; Gong, H. R.
2014-01-01
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.
International Nuclear Information System (INIS)
Vieillard, P.; Lassin, A.; Blanc, P.; Gailhanou, H.; Gaboreau, S.; Gaucher, E.C.; Denoyel, R.; Bloch, E.; Fialips, C.; Giffaut, E.
2012-01-01
Document available in extended abstract form only. In the context of a waste disposal within clayey formations (Callovian-Oxfordian argillite) or using clayey barriers, the prediction of the long-term behavior requires the thermodynamic properties of clay minerals. It has been shown by Gailhanou et al. (submitted) that hydration reactions may have some dramatic consequences on the thermodynamic properties of clay minerals. Different theoretical models exist for extracting thermodynamic properties from water adsorption/desorption isotherms. The present work aims at investigating and comparing these methods, because they can provide very different results based on the assumptions of each models. First, three types of models are compared: 1) the Hill (1949) model based on heat of adsorption combined with adsorption isotherm, 2) the Jura and Hill (1951) model, based on the Clausius-Clapeyron relation, and 3) the BET theory. Both have been designed in order to describe surface sorption phenomena. For instance, they suppose that the number of sorption sites is constant during all the vapor sorption process (and at any relative humidity, P/P 0 ). The hydration reaction approach can also be used. Compared to the three previous models, it is not structurally constrained, except for mass balance considerations on the H 2 O component. It had been especially developed by Tardy and Touret, (1985) and modified into a solid solution model, first by Ransom and Helgeson, (1994). It relies simply on the reaction: Clay(dehydrated) + nH 2 O = Clay(hydrated).nH 2 O. The different families of models have been compared to experimental measurements performed on a sodic smectite MX80. The set of experiments includes a series of three adsorption/desorption isotherms obtained at 25, 45 and 60 C and a heat of adsorption combined with a adsorption isotherm obtained at 25 C. The heat of adsorption was derived from the 3 adsorption/desorption isotherms by using the different models. Then
Review and assessment of thermodynamic and transport properties for the CONTAIN Code
International Nuclear Information System (INIS)
Valdez, G.D.
1988-12-01
A study was carried out to review available data and correlations on the thermodynamic and transport properties of materials applicable to the CONTAIN computer code. CONTAIN is the NRC's best-estimate, mechanistic computer code for modeling containment response to a severe accident. Where appropriate, recommendations have been made for suitable approximations for material properties of interests. Based on a modified Benedict-Webb-Rubin (BWR) equation of state, a procedure is introduced for calculating thermodynamic properties for common gases in the CONTAIN code. These gases are nitrogen, oxygen, hydrogen, carbon dioxide, carbon monoxide, steam, helium, and argon. The thermodynamic equations for density, currently represented in CONTAIN by relatively simple fits, were independently checked and are recommended to be replaced by the Lee-Kesler equation of state which substantially improves accuracy without too much sacrifice in computational efficiency. The accuracy of the calculated values have been found to be generally acceptable. Various correlations and models for single component gas transport properties, viscosity and thermal conductivity, were also assessed with available experimental data. When a suitable correlation or model was not available, transport properties were obtained by performing least-squares fit on experimental data. 50 refs., 126 figs., 3 tabs
ELECTRICAL AND THERMODYNAMIC PROPERTIES OF A COLLAGEN SOLUTION
Directory of Open Access Journals (Sweden)
Jaromír Štancl
2017-06-01
Full Text Available This paper focuses on measurements of the electrical properties, the specific heat capacity and the thermal conductivity of a collagen solution (7.19% mass fraction of native bovine collagen in water. The results of our experiments show that specific electrical conductivity of collagen solution is strongly dependent on temperature. The transition region of collagen to gelatin has been observed from the measured temperature dependence of specific electrical conductivity, and has been confirmed by specific heat capacity measurements by a differential scanning calorimetry.
Thermodynamic properties and atomic structure of Ca-based liquid alloys
Poizeau, Sophie
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 determined by emf measurements. It was found that Sb as positive electrode would provide the highest voltage for Ca-based liquid metal batteries (1 V). The price of such a battery would be competitive for the grid-scale energy storage market. The impact of Pb, a natural impurity of Sb, was predicted successfully and confirmed via electrochemical measurements. It was shown that the impact on the open circuit voltage would be minor. Indeed, the interaction between Ca and Sb was demonstrated to be much stronger than between Ca and Pb using thermodynamic modeling, which explains why the partial thermodynamic properties of Ca would not vary much with the addition of Pb to Sb. However, the usage of the positive electrode would be reduced, which would limit the interest of a Pb-Sb positive electrode. Throughout this work, the molecular interaction volume model (MIVM) was used for the first time for alloys with thermodynamic properties showing strong negative deviation from ideality. This model showed that systems such as Ca-Sb have strong short-range order: Ca is most stable when its first nearest neighbors are Sb. This is consistent with what the more traditional thermodynamic model, the regular association model, would predict. The advantages of the MIVM are the absence of assumption regarding the composition of an associate, and the reduced number of fitting parameters (2 instead of 5). Based on the parameters derived from the thermodynamic modeling using the MIVM, a new potential of mixing for liquid alloys was defined to compare the strength of interaction in different Ca-based alloys. Comparing this trend with the strength of interaction in the solid state of these systems (assessed by the energy of formation of the intermetallics), the systems with
An Equation of State for the Thermodynamic Properties of Cyclohexane
Energy Technology Data Exchange (ETDEWEB)
Zhou, Yong, E-mail: Yong.Zhou2@honeywell.com; Liu, Jun [Honeywell Integrated Technology China Co. Ltd., 430 Li Bing Road, Zhangjiang Hi-Tech Park, Shanghai 201203 (China); Penoncello, Steven G. [Center for Applied Thermodynamic Studies, College of Engineering, University of Idaho, Moscow, Idaho 83844 (United States); Lemmon, Eric W. [Applied Chemicals and Materials Division, National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305 (United States)
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 pρT, 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.
Thermodynamic and transport properties of uranium dioxide and related phases
International Nuclear Information System (INIS)
1965-01-01
The high melting point of uranium dioxide and its stability under irradiation have led to its use as a fuel in a variety of types of nuclear reactors. A wide range of chemical and physical studies has been stimulated by this circumstances and by the complex nature of the uranium dioxide phase itself. The boundaries of this phase widen as the temperature is increased; at 2000 deg. K a single, homogeneous phase exists from U 2.27 to a hypostoichiometric (UO 2-x ) composition, depending on the oxygen potential of the surroundings. Since there is often an incentive to operate a reactor at the maximum practicable heat rating and, therefore, maximum thermal gradient in the fuel, the determination of the physical properties of the UO 2-x phase becomes a matter of great technological importance. In addition a complex sequence of U-O phases may be formed during the preparation of powder feed material or during the sintering process; these affect the microstructure and properties of the final product and have also received much attention. 184 refs, 33 figs, 15 tabs
Thermodynamic properties of short-range square well fluid
López-Rendón, R.; Reyes, Y.; Orea, P.
2006-08-01
The interfacial properties of short-range square well fluid with λ =1.15, 1.25, and 1.375 were determined by using single canonical Monte Carlo simulations. Simulations were carried out in the vapor-liquid region. The coexistence curves of these models were calculated and compared to those previously reported in the literature and good agreement was found among them. We found that the surface tension curves for any potential model of short range form a single master curve when we plot γ* vs T /Tc. It is demonstrated that the critical reduced second virial coefficient B2* as a function of interaction range or Tc* is not constant.
Two-temperature thermodynamic and transport properties of SF6–Cu plasmas
International Nuclear Information System (INIS)
Wu, Yi; Chen, Zhexin; Yang, Fei; Rong, Mingzhe; Sun, Hao; Cressault, Yann; Murphy, Anthony B; Guo, Anxiang; Liu, Zirui
2015-01-01
SF 6 and Cu are widely adopted in electrical equipment as a dielectric medium and for conductive components, respectively. SF 6 –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 SF 6 –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 SF 6 –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. (paper)
Thermodynamic and surface properties of liquid Co–Cr–Ni alloys
International Nuclear Information System (INIS)
Costa, C.; Delsante, S.; Borzone, G.; Zivkovic, D.; Novakovic, R.
2014-01-01
Highlights: • The liquid phases of Co–Cr, Co–Ni and Cr–Ni were modelled by the Quasi Chemical Approximation for regular solutions. • The excess Gibbs free energy of mixing of the liquid Co–Cr–Ni phase is estimated by the three thermodynamic models. • Prediction of structure can compensate the lack of structural data of Co–Cr, Co–Ni and Cr–Ni melts. • Thermodynamic modelling of the surface properties of Co–Cr–Ni melts. • Weak effects of short range ordering among nearest neighbours in Co–Cr, Co–Ni and Cr–Ni liquid alloys can be deduced. -- Abstract: Direct measurements of bulk and surface properties of liquid alloys at elevated temperatures are often technically difficult or even impossible, and therefore, theoretical models can be used to estimate missing property values. The energetics of mixing in liquid Co–Cr, Cr–Ni and Co–Ni systems has been analysed through the study of the concentration dependence of various thermodynamic, surface (surface tension and surface composition) and structural properties (concentration fluctuations in the long-wavelength limit and chemical short-range order parameter) by the first or the Quasi-Chemical Approximation (QCA) for regular solutions, developed by Bhatia and Singh, in the framework of statistical mechanical theory in conjunction with the Quasi-Lattice Theory (QLT). The results obtained for these binary systems have been extended to study the thermodynamics and surface properties of ternary Co–Cr–Ni liquid alloys
Nuclear physics: Macroscopic aspects
International Nuclear Information System (INIS)
Swiatecki, W.J.
1993-12-01
A systematic macroscopic, leptodermous approach to nuclear statics and dynamics is described, based formally on the assumptions ℎ → 0 and b/R << 1, where b is the surface diffuseness and R the nuclear radius. The resulting static model of shell-corrected nuclear binding energies and deformabilities is accurate to better than 1 part in a thousand and yields a firm determination of the principal properties of the nuclear fluid. As regards dynamics, the above approach suggests that nuclear shape evolutions will often be dominated by dissipation, but quantitative comparisons with experimental data are more difficult than in the case of statics. In its simplest liquid drop version the model exhibits interesting formal connections to the classic astronomical problem of rotating gravitating masses
MAPLIB, Thermodynamics Materials Property Generator for FORTRAN Program
International Nuclear Information System (INIS)
Schumann, U.; Zimmerer, W. and others
1978-01-01
1 - Nature of physical problem solved: MAPLIB is a program system which is able to incorporate the values of the properties of any material in a form suitable for use in other computer programs. The data are implemented in FORTRAN functions. A utility program is provided to assist in library management. 2 - Method of solution: MAPLIB consists of the following parts: 1) Conventions for the data format. 2) Some integrated data. 3) A data access system (FORTRAN subroutine). 4) An utility program for updating and documentation of the actual library content. The central part is a set of FORTRAN functions, e.g. WL H2O v(t,p) (heat conduction of water vapor as a function of temperature and pressure), which compute the required data and which can be called by the user program. The data content of MAPLIB has been delivered by many persons. There was no systematic evaluation of the material. It is the responsibility of every user to check the data for physical accuracy. MAPLIB only serves as a library system for manipulation and storing of such data. 3 - Restrictions on the complexity of the problem: a) See responsibility as explained above. b) Up to 1000 data functions could be implemented. c) If too many data functions are included in MAPLIB, the storage requirements become excessive for application in users programs
Thermodynamic properties of 1-butyl-3-methylpyridinium tetrafluoroborate
International Nuclear Information System (INIS)
Safarov, Javid; Kul, Ismail; El-Awady, Waleed A.; Shahverdiyev, Astan; Hassel, Egon
2011-01-01
Highlights: → (p, ρ, T) data of 1-butyl-3-methylpyridinium tetrafluoroborate are estimated. → The measurements were carried out with a vibration-tube densimeter. → The thermomechanical coefficients were calculated. - Abstract: Pressure, density, temperature (p, ρ, T) data of 1-butyl-3-methylpyridinium tetrafluoroborate [C4mpyr][BF 4 ] at T = (283.15 to 393.15) K and pressures up to p = 100 MPa are reported with an estimated experimental relative combined standard uncertainty of Δρ/ρ = ±(0.01 to 0.08)% in density. The measurements were carried out with a newly constructed Anton-Paar DMA HPM vibration-tube densimeter. The system was calibrated using double-distilled water, methanol, toluene and aqueous NaCl solutions. An empirical equation of state for fitting of the (p, ρ, T) data of [C4mpyr][BF 4 ] has been developed as a function of pressure and temperature to calculate the thermal properties of the ionic liquid (IL), such as isothermal compressibility, isobaric thermal expansibility, differences in isobaric and isochoric heat capacities, thermal pressure coefficient and internal pressure. Internal pressure and the temperature coefficient of internal pressure data were used to make conclusions on the molecular characteristics of the IL.
Thermodynamic study of alkane-α,ω-diamines - evidence of odd-even pattern of sublimation properties
Czech Academy of Sciences Publication Activity Database
Fulem, Michal; Růžička, K.; Červinka, C.; Bazyleva, A.; Della Gatta, G.
2014-01-01
Roč. 371, Jun (2014), s. 93-105 ISSN 0378-3812 Institutional support: RVO:68378271 Keywords : alkane-diamines * odd–even effect * vapor pressure * sublimation and vaporization thermodynamic properties * statistical thermodynamics Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.200, year: 2014
Montes-Perez, J; Cruz-Vera, A; Herrera, J N
2011-12-01
This work presents the full analytic expressions for the thermodynamic properties and the static structure factor for a hard sphere plus 1-Yukawa fluid within the mean spherical approximation. To obtain these properties of the fluid type Yukawa analytically it was necessary to solve an equation of fourth order for the scaling parameter on a large scale. The physical root of this equation was determined by imposing physical conditions. The results of this work are obtained from seminal papers of Blum and Høye. We show that is not necessary the use the series expansion to solve the equation for the scaling parameter. We applied our theoretical result to find the thermodynamic and the static structure factor for krypton. Our results are in good agreement with those obtained in an experimental form or by simulation using the Monte Carlo method.
Pressure effect on structural, elastic, and thermodynamic properties of tetragonal B4C4
Directory of Open Access Journals (Sweden)
Baobing Zheng
2015-03-01
Full Text Available The compressibility, elastic anisotropy, and thermodynamic properties of the recently proposed tetragonal B4C4 (t-B4C4 are investigated under high temperature and high pressure by using of first-principles calculations method. The elastic constants, bulk modulus, shear modulus, Young’s modulus, Vickers hardness, Pugh’s modulus ratio, and Poisson’s ratio for t-B4C4 under various pressures are systematically explored, the obtained results indicate that t-B4C4 is a stiffer material. The elastic anisotropies of t-B4C4 are discussed in detail under pressure from 0 GPa to 100 GPa. The thermodynamic properties of t-B4C4, such as Debye temperature, heat capacity, and thermal expansion coefficient are investigated by the quasi-harmonic Debye model.
Directory of Open Access Journals (Sweden)
Bidai K.
2017-06-01
Full Text Available First-principles density functional theory calculations have been performed to investigate the structural, elastic and thermodynamic properties of rubidium telluride in cubic anti-fluorite (anti-CaF2-type structure. The calculated ground-state properties of Rb2Te compound such as equilibrium lattice parameter and bulk moduli are investigated by generalized gradient approximation (GGA-PBE that are based on the optimization of total energy. The elastic constants, Young’s and shear modulus, Poisson ratio, have also been calculated. Our results are in reasonable agreement with the available theoretical and experimental data. The pressure dependence of elastic constant and thermodynamic quantities under high pressure are also calculated and discussed.
Thermodynamic properties of liquid copper-indium-tin alloys determined from e.m.f. measurements
International Nuclear Information System (INIS)
Jendrzejczyk-Handzlik, Dominika; Gierlotka, Wojciech; Fitzner, Krzysztof
2009-01-01
The thermodynamics properties of liquid Cu-In-Sn alloys were determined using solid oxide galvanic cells with zirconia electrolyte: (I)Re+kanthal,Cu x -In y -Sn (1-x-y) ,'In 2 O 3 '//ZrO 2 +(Y 2 O 3 )//NiO,Ni,Pt in the temperature range (973 to 1223) K. Applied In 2 O 3 can be either pure or in the solid solutions with SnO 2 . Thermodynamics properties of the liquid phase were described by the Redlich-Kister-Muggianu formula. Using the commercial software different phase relations in the ternary system were calculated and compared with experimental data found in the literature
Ab-initio study of thermodynamic properties of boron nanowire at atomic scale
Bhuyan, Prabal D.; Gupta, Sanjeev K.; Sonvane, Y.; Gajjar, P. N.
2018-04-01
In the present work, we have optimized ribbon like zigzag structure of boron (B) nanowire (NW) and investigated vibrational and thermodynamic properties using quasi-harmonic approximations (QHA). All positive phonon in the phonon dispersive curve have confirmed dynamical stability of ribbon B-NW. The thermodynamic properties, like Debye temperature, internal energy and specific heat, are calculated as a function of temperature. The variation of specific heat is proportional to T3 Debye law at lower temperature for B-NW, while it becomes constant above room temperature at 1200K; obeys Dulong-Petit's law. The high Debye temperature of 1120K is observed at ambient temperature, which can be attributed to high thermal conductivity. Our study shows that B-NW with high thermal conductivity could be the next generation electron connector for nanoscale electronic devices.
Thermodynamic properties of bcc crystals at high temperatures: The transition metals
International Nuclear Information System (INIS)
MacDonald, R.A.; Shukla, R.C.
1985-01-01
The second-neighbor central-force model of a bcc crystal, previously used in lowest-order anharmonic perturbation theory to calculate the thermodynamic properties of the alkali metals, is here applied to the transition metals V, Nb, Ta, Mo, and W. The limitations of the model are apparent in the thermal-expansion results, which fall away from the experimental trend above about 1800 K. The specific heat similarly fails to exhibit the sharp rise that is observed at higher temperatures. A static treatment of vacancies cannot account for the difference between theory and experiment. The electrons have been taken into account by using a model that specifically includes d-band effects in the electron ground-state energy. The results thus obtained for the bulk moduli are quite satisfactory. In the light of these results, we discuss the prerequisites for a better treatment of metals when the electrons play an important role in determining the thermodynamic properties
The thermodynamic properties of the upper continental crust: Exergy, Gibbs free energy and enthalpy
International Nuclear Information System (INIS)
Valero, Alicia; Valero, Antonio; Vieillard, Philippe
2012-01-01
This paper shows a comprehensive database of the thermodynamic properties of the most abundant minerals of the upper continental crust. For those substances whose thermodynamic properties are not listed in the literature, their enthalpy and Gibbs free energy are calculated with 11 different estimation methods described in this study, with associated errors of up to 10% with respect to values published in the literature. Thanks to this procedure we have been able to make a first estimation of the enthalpy, Gibbs free energy and exergy of the bulk upper continental crust and of each of the nearly 300 most abundant minerals contained in it. Finally, the chemical exergy of the continental crust is compared to the exergy of the concentrated mineral resources. The numbers obtained indicate the huge chemical exergy wealth of the crust: 6 × 10 6 Gtoe. However, this study shows that approximately only 0.01% of that amount can be effectively used by man.
Kinetics and thermodynamic properties related to the drying of 'Cabacinha' pepper fruits
Hellismar W. da Silva; Renato S. Rodovalho; Marya F. Velasco; Camila F. Silva; Luís S. R. Vale
2016-01-01
ABSTRACT The objective of this study was to determine and model the drying kinetics of 'Cabacinha' pepper fruits at different temperatures of the drying air, as well as obtain the thermodynamic properties involved in the drying process of the product. Drying was carried out under controlled conductions of temperature (60, 70, 80, 90 and 100 °C) using three samples of 130 g of fruit, which were weighed periodically until constant mass. The experimental data were adjusted to different mathemati...
Thermodynamic properties of sticky electrolytes in the HNC/MS approximation
International Nuclear Information System (INIS)
Herrera, J.N.; Blum, L.
1991-01-01
We study an approximation for a model which combines the sticky potential of Baxter and charged spheres. In the hypernetted chain (HNC)/mean spherical approximation (MSA), simple expressions for the thermodynamic functions are obtained. There equations should be useful in representing the properties of real electrolytes. Approximate expressions that are similar to those of the primitive model are obtained, for low densities (concentrations) of the electrolyte (Author)
Energy Technology Data Exchange (ETDEWEB)
Mahendra P, Verma [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)
2005-07-01
In this paper are presented, the thermodynamic inconsistencies in formulation IAPWS-95 as well as the limitations in the experimental data of the thermodynamic properties of the water. In addition, a new methodology was developed: Verma procedure for the measurement of the calorific capacity of water. Thus, a procedure is presented to calculate other thermodynamic properties of liquids such as water. In the transformation processes of the planet Earth, water is an essential component. Nevertheless, the knowledge about its properties is still very limited. Recently, Verma developed a new program: SteamTablesIIE, to calculate the properties of water as a function of two independent variables between temperatures (T), pressure (P), volume (V), internal energy (U), enthalpy (H), Gibas energy (G) and entropy (S). Yet, thermodynamic inconsistencies were found in the formulation, same that are the limiting factors for the operation of the SteamTablesIIE in all the ranks of the independent variables. [Spanish] En este trabajo se presentan, tanto las inconsistencias termodinamicas en la formulacion IAPWS-95 como las limitaciones en los datos experimentales de las propiedades termodinamicas del agua. Ademas, se desarrollo una nueva metodologia: Procedimiento Verma para la medicion de la capacidad calorifica del agua. Asi, se presenta un procedimiento para calcular otras propiedades termodinamicas de liquidos tales como el agua. En los procesos de transformacion del planeta tierra, el agua es un componente esencial. Sin embargo, el conocimiento acerca de sus propiedades es todavia muy limitado. Recientemente, Verma desarrollo un nuevo programa: SteamTablesIIE, para calcular las propiedades del agua como una funcion de dos variables independientes entre temperaturas (T), presion (P), volumen (V), energia interna (U), entalpia (H), energia Gibas (G) y entropia (S). Con todo, se encontraron inconsistencias termodinamicas en la formulacion, mismas que son las limitantes para el
Optimization of the thermodynamic properties and phase diagrams of P2O5-containing systems
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
Thermodynamic and transport properties of two-temperature SF6 plasmas
International Nuclear Information System (INIS)
Wang Weizong; Rong Mingzhe; Wu Yi; Spencer, Joseph W.; Yan, Joseph D.; Mei, DanHua
2012-01-01
This paper deals with thermodynamic and transport properties of SF 6 plasmas in a two-temperature model for both thermal equilibrium and non-equilibrium conditions. The species composition and thermodynamic properties are numerically determined using the two-temperature Saha equation and Guldberg-Waage equation according to deviation of van de Sanden et al. Transport properties including diffusion coefficient, viscosity, thermal conductivity, and electrical conductivity are calculated with most recent collision interaction potentials by adopting Devoto’s electron and heavy particle decoupling approach but expanded to the third-order approximation (second-order for viscosity) in the frame of Chapman–Enskog method. The results are computed for various values of pressures from 0.1 atm to 10 atm and ratios of the electron temperature to the heavy particle temperature from 1 to 20 with electron temperature range from 300 to 40 000 K. In the local thermodynamic equilibrium regime, results are compared with available results of previously published studies.
D2O, Computation of Thermodynamic and Transport Properties of Heavy Water
International Nuclear Information System (INIS)
Durmayaz, Ahmet
2000-01-01
1 - Description of program or function: A computer program for the fast computation of the thermodynamic and transport properties of heavy water (D 2 O) at saturation, in subcooled liquid and superheated vapor states. Specific volume (or density), specific enthalpy, specific entropy, constant-pressure specific heat and temperature at saturation are calculated by a number of piecewise continuous approximation functions of (and their derivatives are calculated with respect to) pressure whereas pressure at saturation is calculated by a piecewise continuous approximation function of temperature for heavy water. Density in subcooled liquid state, specific volume in super-heated vapor state, specific enthalpy, specific entropy and constant-pressure specific heat in both of these states are calculated by some piecewise continuous approximation functions of pressure and temperature for heavy water. The correlations used in the calculation of these thermodynamic properties of heavy water were derived by fitting some appropriate curves to the data given in the steam tables by Hill et al (1981). The whole set of correlations and the approximation method used in their derivation are presented by Durmayaz (1997). Dynamic viscosity and thermal conductivity for heavy water are calculated as functions of temperature and density with the correlations given by Hill et al (1981), by Matsunaga and Nagashima (1983) and by Kestin et al (1984). Surface tension for heavy water is calculated as a function of temperature with the correlation given by Crabtree and Siman-Tov (1993). 2 - Methods: A group of pressure-enthalpy (P-h) pairs can be given in an input data file or assigned in the main program without knowing the state in which fluid takes place. In this case, first, the enthalpies at saturation corresponding to the given pressure are computed. Second, the state is determined by comparing the given enthalpy to the saturation enthalpies. Then, the properties are computed. Program D 2 O
Thermodynamic properties of 1-naphthol: Mutual validation of experimental and computational results
International Nuclear Information System (INIS)
Chirico, Robert D.; Steele, William V.; Kazakov, Andrei F.
2015-01-01
Highlights: • Heat capacities were measured for the temperature range 5 K to 445 K. • Vapor pressures were measured for the temperature range 370 K to 570 K. • Computed and derived properties for ideal gas entropies are in excellent accord. • The enthalpy of combustion was measured and shown to be consistent with reliable literature values. • Thermodynamic consistency analysis revealed anomalous literature data. - Abstract: Thermodynamic properties for 1-naphthol (Chemical Abstracts registry number [90-15-3]) in the ideal-gas state are reported based on both experimental and computational methods. Measured properties included the triple-point temperature, enthalpy of fusion, and heat capacities for the crystal and liquid phases by adiabatic calorimetry; vapor pressures by inclined-piston manometry and comparative ebulliometry; and the enthalpy of combustion of the crystal phase by oxygen bomb calorimetry. Critical properties were estimated. Entropies for the ideal-gas state were derived from the experimental studies for the temperature range 298.15 ⩽ T/K ⩽ 600, and independent statistical calculations were performed based on molecular geometry optimization and vibrational frequencies calculated at the B3LYP/6-31+G(d,p) level of theory. The mutual validation of the independent experimental and computed results is achieved with a scaling factor of 0.975 applied to the calculated vibrational frequencies. This same scaling factor was successfully applied in the analysis of results for other polycyclic molecules, as described in a series of recent articles by this research group. This article reports the first extension of this approach to a hydroxy-aromatic compound. All experimental results are compared with property values reported in the literature. Thermodynamic consistency between properties is used to show that several studies in the literature are erroneous. The enthalpy of combustion for 1-naphthol was also measured in this research, and excellent
Free energy of formation of Mo2C and the thermodynamic properties of carbon in solid molybdenum
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.
Choice of the thermodynamic variables
International Nuclear Information System (INIS)
Balian, R.
1985-09-01
Some basic ideas of thermodynamics and statistical mechanics, both at equilibrium and off equilibrium, are recalled. In particular, the selection of relevant variables which underlies any macroscopic description is discussed, together with the meaning of the various thermodynamic quantities, in order to set the thermodynamic approaches used in nuclear physics in a general prospect [fr
Chandel, Namrata; Mehta, Neeraj
2018-04-01
In this study, we prepared novel selenium rich multi-component glasses by incorporating In, Cd and Sb as foreign elements in an Sn containing Sesbnd Te system in order to study their metal-induced effects on the thermal properties of the parent ternary glass. In particular, we determined the thermodynamic parameters of Se80Te18Sn2 and Se80Te8Sn2M10 (M = Cd, In, Sb) glassy semiconductors in a non-isothermal environment using the differential scanning calorimetry. Calorimetric measurements were obtained in the glass transition regions for Se80Te18Sn2 and Se80Te8Sn2M10 (M = Cd, In, Sb) glasses to determine their thermodynamic parameters such as the specific heat, enthalpy, and entropy during glass transition. We analyzed the variation in the specific heat before and after the heat capacity jump in these alloys. The metal-induced effects of foreign elements on the thermodynamic properties of the parent glass were also investigated in terms of the influence of the elemental specific heat of the added elemental metal as well as the thermal stability and glass-forming ability of the glasses.
Precision measurement of the speed of sound and thermodynamic properties of gases
International Nuclear Information System (INIS)
Benedetto, G.; Gavioso, R.M.; Spagnolo, R.
1999-01-01
The speed of sound in pure fluids and mixtures is a characteristic and important physical propriety which depends of several intensive thermodynamic variables. This fact indicates that it can be calculated using the appropriate thermodynamic properties of the fluid. Alternatively, experimental evaluation of the speed of sound can be used to determine several fundamental thermophysical properties. Recently, very accurate measurements of the speed of sound in dilute gases have found relevant applications: 1) the last experimental determinations of the value of the universal gas constant R, by measurements in argon, at the triple point of water (1,2); 2) revision of the thermodynamic temperature scales in different temperature ranges (3-5); 3) derivation of the state of many pure gases, which includes methane, helium and ethylene (6-7); 4)determination of the heat capacities and densities of pure gases and mixture (8-16). The aim of this paper is to provide an extensive review of the measurement of the speed of sound in gases and of its theoretical basis, giving prominence to the relevant metrological aspects involved in the determination of this physical quantity
Thermodynamic and elastic properties of hexagonal ZnO under high temperature
International Nuclear Information System (INIS)
Wang, Feng; Wu, Jinghe; Xia, Chuanhui; Hu, Chenghua; Hu, Chunlian; Zhou, Ping; Shi, Lingna; Ji, Yanling; Zheng, Zhou; Liu, Xiankun
2014-01-01
Highlights: • A new method is applied to predict crystal constants of hexagonal crystal under high temperature. • Elastic properties of ZnO under high temperature are obtained exactly. • Thermodynamic properties of ZnO under high temperature are attained too. - Abstract: Studies on thermodynamic and elastic properties of hexagonal ZnO (wurtzite structure) under high temperature have not been reported usually from no matter experimental or theoretic methods. In this work, we study these properties by ab-initio together with quasi-harmonic Debye model. The value of C v tends to the Petit and Dulong limit at high temperature under any pressure, 49.73 J/mol K. And C v is greatly limited by pressure at intermediate temperatures. Nevertheless, the limit effect on C v caused by pressure is not obvious under low as well as very high temperature. The thermal expansions along a or c axis are almost same under temperature, which increase with temperature like a parabola. C 11 , C 33 , C 12 and C 13 decrease with temperature a little, which means that mechanics properties are weakened respectively
International Nuclear Information System (INIS)
Chirico, Robert D.; Kazakov, Andrei F.; Steele, William V.
2012-01-01
Highlights: ► Heat capacities were measured for the temperature range 5 K to 520 K. ► Vapor pressures were measured for the temperature range 368 K to 668 K. ► The enthalpy of combustion was measured and the enthalpy of formation was derived. ► Calculated and derived properties for the ideal gas are in excellent accord. ► Thermodynamic consistency analysis revealed anomalous literature data. - Abstract: Measurements leading to the calculation of thermodynamic properties for 9-fluorenone (IUPAC name 9H-fluoren-9-one and Chemical Abstracts registry number [486-25-9]) in the ideal-gas state are reported. Experimental methods were adiabatic heat-capacity calorimetry, inclined-piston manometry, comparative ebulliometry, and combustion calorimetry. Critical properties were estimated. Molar entropies for the ideal-gas state were derived from the experimental studies at selected temperatures T between T = 298.15 K and T = 600 K, and independent statistical calculations were performed based on molecular geometry optimization and vibrational frequencies calculated at the B3LYP/6 − 31 + G(d,p) level of theory. Values derived with the independent methods are shown to be in excellent accord with a scaling factor of 0.975 applied to the calculated frequencies. This same scaling factor was successfully applied in the analysis of results for other polycyclic molecules, as described in recent articles by this research group. All experimental results are compared with property values reported in the literature. Thermodynamic consistency between properties is used to show that several studies in the literature are erroneous.
International Nuclear Information System (INIS)
Sundman, B.; Gueneau, C.
2013-01-01
Computational Thermodynamics is based on physically realistic models to describe metallic and oxide crystalline phases as well as the liquid and gas in a consistent manner. The models are used to assess experimental and theoretical data for many different materials and several thermodynamic databases has been developed for steels, ceramics, semiconductor materials as well as materials for nuclear applications. Within CEA a long term work is ongoing to develop a database for the properties of nuclear fuels and structural materials. An overview of the modelling technique will be given and several examples of the application of the database to different problems, both for traditional phase diagram calculations and its use in simulating phase transformations. The following diagrams (Fig. 1, Fig. 2 and Fig.3) show calculations in the U-Pu-O system. (authors)
International Nuclear Information System (INIS)
Andryushchenko, A.I.; Dubinin, A.B.; Krylov, E.E.
1988-01-01
The problem of choice of working fluids for NPP closed gas turbines (CGT) is discussed. Thermostable in the working temperature range, chemically inert relatively to structural materials, fire- and explosion - proof substances, radiation-resistant and having satisfactory neutron-physical characteristics are used as the working fluids. Final choice of a gas as a working fluid is exercised based on technical and economic comparison of different variants at optimum thermodynamic cycle and parameters for each gas. The character and degree of the effect of thermodynamic properties of gases on configuration of reference cycles of regenerative CGT are determined. It is established that efficiency and optimum parameters in nodal points of the reference cycle are specified by the degree of removing the compression processes from the critical point. Practical importance of the obtained results presupposes the possibility of rapid estimation of the efficiency of using a gas without multiparametric optimization
Thermodynamic properties of Mg2Si and Mg2Ge investigated by first principles method
International Nuclear Information System (INIS)
Wang, Hanfu; Jin, Hao; Chu, Weiguo; Guo, Yanjun
2010-01-01
The lattice dynamics and thermodynamic properties of Mg 2 Si and Mg 2 Ge are studied based on the first principles calculations. We obtain the phonon dispersion curves and phonon density of states spectra using the density functional perturbation theory with local density approximations. By employing the quasi-harmonic approximation, we calculate the temperature dependent Helmholtz free energy, bulk modulus, thermal expansion coefficient, specific heat, Debye temperature and overall Grueneisen coefficient. The results are in good agreement with available experimental data and previous theoretical studies. The thermal conductivities of both compounds are then estimated with the Slack's equation. By carefully choosing input parameters, especially the acoustic Debye temperature, we find that the calculated thermal conductivities agree fairly well with the experimental values above 80 K for both compounds. This demonstrates that the lattice thermal conductivity of simple cubic semiconductors may be estimated with satisfactory accuracy by combining the Slack's equation with the necessary thermodynamics parameters derived completely from the first principles calculations.
A re-assessment of the thermodynamic properties of iodine condensed phases
International Nuclear Information System (INIS)
Arblaster, J.W.
2011-01-01
Highlights: → In the low temperature region below 298.15 K all previous reviews included highly discrepant experimental data points which should have been rejected. In the present review these data points have been rejected leading to a smooth specific heat curve similar to that obtained for solid bromine. The current values, especially at 298.15 K therefore differ considerably from other reviews but it is suggested are more acceptable. → For temperatures above 298.15 K previous reviews carried out unnecessary corrections to the experimental enthalpy measurements and therefore arrived at distorted values for the thermodynamic properties and since these corrections differed from one review to the next then the situation existed where different sets of thermodynamic tables existed and there was no way to suggest which was the correct one. In the present review the experimental values have been used without correction for calibration and therefore again represent a superior set of tables. → Since iodine is solid at room temperature then the question arises as to whether or not to divide the thermodynamic tables in to low temperature values based on 0 K and high temperature values based on 298.15 K. In this paper the values are based on 0 K only to be consistent with the analogues chlorine and bromine. However if in the opinion of the referees the divide ought to be used in this can be achieved quite easily. - Abstract: Thermodynamic properties of iodine have been calculated to 500 K. Specific heat anomalies accepted for the solid phase in previous reviews have been eliminated and a smooth specific heat curve derived. Corrections previously applied to high temperature solid and liquid enthalpy measurements were shown to be unnecessary.
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.
Nadi, Fatemeh; Tzempelikos, Dimitrios
2018-01-01
In this work, apples of cv. Golden Delicious were cut into slices that were 5 and 7 mm thick and then vacuum dried at 50, 60 and 70 °C and pressure of 0.02 bar. The thin layer model drying kinetics was studied, and mass transfer properties, specifically effective moisture diffusivity and convective mass transfer coefficient, were evaluated using the Fick's equation of diffusion. Also, thermodynamic parameters of the process, i.e. enthalpy (ΔH), entropy (ΔS) and Gibbs free energy (ΔG), were determined. Colour properties were evaluated as one of the important indicators of food quality and marketability. Determination of mass transfer parameters and thermodynamic properties of vacuum dried apple slices has not been discussed much in the literature. In conclusion, the Nadi's model fitted best the observed data that represent the drying process. Thermodynamic properties were determined based on the dependence of the drying constant of the Henderson and Pabis model on temperature, and it was concluded that the variation in drying kinetics depends on the energy contribution of the surrounding environment. The enthalpy and entropy diminished, while the Gibbs free energy increased with the increase of the temperature of drying; therefore, it was possible to verify that variation in the diffusion process in the apple during drying depends on energetic contributions of the environment. The obtained results showed that diffusivity increased for 69%, while the mass transfer coefficient increase was even higher, 75%, at the variation of temperature of 20 °C. The increase in the dimensionless Biot number was 20%.
Directory of Open Access Journals (Sweden)
Dallakyan Sargis
2008-08-01
Full Text Available Abstract Background Gram-negative bacteria use periplasmic-binding proteins (bPBP to transport nutrients through the periplasm. Despite immense diversity within the recognized substrates, all members of the family share a common fold that includes two domains that are separated by a conserved hinge. The hinge allows the protein to cycle between open (apo and closed (ligated conformations. Conformational changes within the proteins depend on a complex interplay of mechanical and thermodynamic response, which is manifested as an increase in thermal stability and decrease of flexibility upon ligand binding. Results We use a distance constraint model (DCM to quantify the give and take between thermodynamic stability and mechanical flexibility across the bPBP family. Quantitative stability/flexibility relationships (QSFR are readily evaluated because the DCM links mechanical and thermodynamic properties. We have previously demonstrated that QSFR is moderately conserved across a mesophilic/thermophilic RNase H pair, whereas the observed variance indicated that different enthalpy-entropy mechanisms allow similar mechanical response at their respective melting temperatures. Our predictions of heat capacity and free energy show marked diversity across the bPBP family. While backbone flexibility metrics are mostly conserved, cooperativity correlation (long-range couplings also demonstrate considerable amount of variation. Upon ligand removal, heat capacity, melting point, and mechanical rigidity are, as expected, lowered. Nevertheless, significant differences are found in molecular cooperativity correlations that can be explained by the detailed nature of the hydrogen bond network. Conclusion Non-trivial mechanical and thermodynamic variation across the family is explained by differences within the underlying H-bond networks. The mechanism is simple; variation within the H-bond networks result in altered mechanical linkage properties that directly affect
Structural and Thermodynamic Properties of Amyloid-β Peptides: Impact of Fragment Size
Kitahara, T.; Wise-Scira, O.; Coskuner, O.
2010-10-01
Alzheimer's disease is a progressive neurodegenerative disease whose physiological characteristics include the accumulation of amyloid-containing deposits in the brain and consequent synapse and neuron loss. Unfortunately, most widely used drugs for the treatment can palliate the outer symptoms but cannot cure the disease itself. Hence, developing a new drug that can cure it. Most recently, the ``early aggregation and monomer'' hypothesis has become popular and a few drugs have been developed based on this hypothesis. Detailed understanding of the amyloid-β peptide structure can better help us to determine more effective treatment strategies; indeed, the structure of Amyloid has been studied extensively employing experimental and theoretical tools. Nevertheless, those studies have employed different fragment sizes of Amyloid and characterized its conformational nature in different media. Thus, the structural properties might be different from each other and provide a reason for the existing debates in the literature. Here, we performed all-atom MD simulations and present the structural and thermodynamic properties of Aβ1-16, Aβ1-28, and Aβ1-42 in the gas phase and in aqueous solution. Our studies show that the overall structures, secondary structures, and the calculated thermodynamic properties change with increasing peptide size. In addition, we find that the structural properties of those peptides are different from each other in the gas phase and in aqueous solution.
Energy Technology Data Exchange (ETDEWEB)
Konstantinova, Elena, E-mail: elena.konst@ifsudestemg.edu.br; Sales, José Antonio de
2014-10-01
Creation of magnetic nanodevices leads, in particular, to a growing interest in theoretical investigation of different types of magnetic nanostructures. The purpose of our work is to consider how the properties of such nanomaterials depend on their geometry and on the crystal structure. We report on the Monte Carlo simulation of magnetic nanostructures of different geometric forms, which are based on simple cubic and body-centered cubic cells. The magnetization of spin, magnetic susceptibility and specific heat are investigated for nano-disks, nano-bars and nano-balls of different magnitudes. The combination of dipole and Heisenberg-model interaction are considered for the ferromagnetic case. It is shown that magnetic and thermodynamic properties of nanostructures strongly depend on their geometry. The structures with a body-centered cubic unit cell manifest stronger dependence on size and geometric form. In this case one can interpret the results as an effective reduction of dimension from 3D to 2D for decreasing size of the compound. - Highlights: • Thermodynamic properties of nano-balls are dependent on their size. • Magnetic properties of nano-bars depend on their thickness. • The hysteresis loop is dependent on the geometry of the nanostructure.
International Nuclear Information System (INIS)
Xu, Liang; Yuan, Jingqi
2015-01-01
Thermodynamic properties of the working fluid and the flue gas play an important role in the thermodynamic calculation for the boiler design and the operational optimization in power plants. In this study, a generic approach to online calculate the thermodynamic properties of the flue gas is proposed based on its composition estimation. It covers the full operation scope of the flue gas, including the two-phase state when the temperature becomes lower than the dew point. The composition of the flue gas is online estimated based on the routinely offline assays of the coal samples and the online measured oxygen mole fraction in the flue gas. The relative error of the proposed approach is found less than 1% when the standard data set of the dry and humid air and the typical flue gas is used for validation. Also, the sensitivity analysis of the individual component and the influence of the measurement error of the oxygen mole fraction on the thermodynamic properties of the flue gas are presented. - Highlights: • Flue gas thermodynamic properties in coal-fired power plants are online calculated. • Flue gas composition is online estimated using the measured oxygen mole fraction. • The proposed approach covers full operation scope, including two-phase flue gas. • Component sensitivity to the thermodynamic properties of flue gas is presented.
International Nuclear Information System (INIS)
Yoneda, A; Sohag, F H
2010-01-01
The bulk physical properties of composite systems are difficult to predict - even when the properties of the constituent materials in the system are well known. We conducted a finite-element method simulation to examine the inclusion effect by substituting an inclusion phase (second phase) into a host phase (first phase). We have organized the simulation results as a function of the elasticity of host and inclusion phases. In this procedure, special attention was paid to the initial change of elastic constants as the inclusion volume ratio was varied. To accomplish this, we introduced a new parameter D ij defined as the derivatives of the normalized stiffness elastic constant over the inclusion volume ratio. We succeeded in obtaining useful systematic formulations for D ij . These formulations are expected to be applicable to the study of composite systems in many disciplines, such as geophysics, mechanics, material engineering, and biology. The present results provide much more effective constraints on the physical properties of composite systems, like rocks, than traditional methods, such as the Voigt-Reuss bounds.
The use of molecular dynamics for the thermodynamic properties of simple and transition metals
International Nuclear Information System (INIS)
Straub, G.K.
1987-04-01
The technique of computer simulation of the molecular dynamics in metallic systems to calculate thermodynamic properties is discussed. The nature of a metal as determined by its electronic structure is used to determine the total adiabatic potential. The effective screened ion-ion interaction can then be used in a molecular dynamics simulation. The method for the construction of a molecular dynamics ensemble, its relation to the canonical ensemble, and the definition of thermodynamic functions from the Helmholtz free energy is given. The method for the analysis of the molecular dynamics results from quasiharmonic lattice dynamics and the decomposition in terms of harmonic and anharmonic contributions is given for solids. For fluid phase metals, procedures for calculating the thermodynamics and determining the constant of entropy are presented. The solid-fluid phase boundary as a function of pressure and temperature is determined using the results of molecular dynamics. Throughout, examples and results for metallic sodium are used. The treatment of the transition metal electronic d-states in terms of an effective pair-wise interaction is also discussed and the phonon dispersion curves of Al, Ni, and Cu are calculated
Calculations of thermodynamic properties of PuO{sub 2} by the first-principles and lattice vibration
Energy Technology Data Exchange (ETDEWEB)
Minamoto, Satoshi [Energy and Industrial Systems Department, ITOCHU Techno-Solutions Corporation, Kasumigaseki 3-chome, Chiyoda-ku, Tokyo 100-6080 (Japan)], E-mail: satoshi.minamoto@ctc-g.co.jp; Kato, Masato [Japan Atomic Energy Agency, 4-33 Muramatsu, Tokai-mura, Naka-gun, Ibaraki 319-1194 (Japan); Konashi, Kenji [Institute for Materials Research, Tohoku University, 2145-2 Narita-chou, Oarai-chou, Ibaraki 311-1313 (Japan); Kawazoe, Yoshiyuki [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan)
2009-03-15
Plutonium dioxide (PuO{sub 2}) is a key compound of mixed oxide fuel (MOX fuel). To predict the thermal properties of PuO{sub 2} at high temperature, it is important to understand the properties of MOX fuel. In this study, thermodynamic properties of PuO{sub 2} were evaluated by coupling of first-principles and lattice dynamics calculation. Cohesive energy was estimated from first-principles calculations, and the contribution of lattice vibration to total energy was evaluated by phonon calculations. Thermodynamic properties such as volume thermal expansion, bulk modulus and specific heat of PuO{sub 2} were investigated up to 1500 K.
Calculations of thermodynamic properties of PuO2 by the first-principles and lattice vibration
International Nuclear Information System (INIS)
Minamoto, Satoshi; Kato, Masato; Konashi, Kenji; Kawazoe, Yoshiyuki
2009-01-01
Plutonium dioxide (PuO 2 ) is a key compound of mixed oxide fuel (MOX fuel). To predict the thermal properties of PuO 2 at high temperature, it is important to understand the properties of MOX fuel. In this study, thermodynamic properties of PuO 2 were evaluated by coupling of first-principles and lattice dynamics calculation. Cohesive energy was estimated from first-principles calculations, and the contribution of lattice vibration to total energy was evaluated by phonon calculations. Thermodynamic properties such as volume thermal expansion, bulk modulus and specific heat of PuO 2 were investigated up to 1500 K
Naden, Levi N; Shirts, Michael R
2016-04-12
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 1000 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 overlap. The existence of regions of poor configuration space overlap are detected by analyzing the eigenvalues of the sampled states' overlap matrix. The configuration space overlap to sampled states is monitored alongside the mean and maximum uncertainty to determine convergence, as neither the uncertainty or the configuration space overlap alone is a sufficient metric of convergence. This adaptive sampling scheme is demonstrated by estimating with high precision the solvation free energies of charged particles of Lennard-Jones plus Coulomb functional form with charges between -2 and +2 and generally physical values of σij and ϵij in TIP3P water. We also compute entropy, enthalpy, and radial distribution functions of arbitrary unsampled parameter combinations using only the data from these sampled states and use the estimates of free energies over the entire space to examine the deviation of atomistic simulations from the Born approximation to the solvation free
Ahmed, Ahfaz
2018-01-30
Rapid compression machines (RCM) are extensively used to study autoignition of a wide variety of fuels at engine relevant conditions. Fuels ranging from pure species to full boiling range gasoline and diesel can be studied in an RCM to develop a better understanding of autoignition kinetics in low to intermediate temperature ranges. In an RCM, autoignition is achieved by compressing a fuel/oxidizer mixture to higher pressure and temperature, thereby initiating chemical reactions promoting ignition. During these experiments, the pressure is continuously monitored and is used to deduce significant events such as the end of compression and the onset of ignition. The pressure profile is also used to assess the temperature evolution of the gas mixture with time using the adiabatic core hypothesis and the heat capacity ratio of the gas mixture. In such RCM studies, real transportation fuels containing many components are often represented by simpler surrogate fuels. While simpler surrogates such as primary reference fuels (PRFs) and ternary primary reference fuel (TPRFs) can match research and motor octane number of transportation fuels, they may not accurately replicate thermodynamic properties (including heat capacity ratio). This non-conformity could exhibit significant discrepancies in the end of compression temperature, thereby affecting ignition delay (τign) measurements. Another aspect of RCMs that can affect τign measurement is post compression heat loss, which depends on various RCM parameters including geometry, extent of insulation, pre-heating temperature etc. To, better understand the effects of these non-chemical kinetic parameters on τign, thermodynamic properties of a number of FACE G gasoline surrogates were calculated and simulated in a multi-zone RCM model. The problem was further investigated using a variance based analysis and individual sensitivities were calculated. This study highlights the effects on τign due to thermodynamic properties of
Ahmed, Ahfaz; Hantouche, Mireille; Khurshid, Muneeb; Mohamed, Samah; Nasir, Ehson Fawad; Farooq, Aamir; Roberts, William L.; Knio, Omar; Sarathy, Mani
2018-01-01
Rapid compression machines (RCM) are extensively used to study autoignition of a wide variety of fuels at engine relevant conditions. Fuels ranging from pure species to full boiling range gasoline and diesel can be studied in an RCM to develop a better understanding of autoignition kinetics in low to intermediate temperature ranges. In an RCM, autoignition is achieved by compressing a fuel/oxidizer mixture to higher pressure and temperature, thereby initiating chemical reactions promoting ignition. During these experiments, the pressure is continuously monitored and is used to deduce significant events such as the end of compression and the onset of ignition. The pressure profile is also used to assess the temperature evolution of the gas mixture with time using the adiabatic core hypothesis and the heat capacity ratio of the gas mixture. In such RCM studies, real transportation fuels containing many components are often represented by simpler surrogate fuels. While simpler surrogates such as primary reference fuels (PRFs) and ternary primary reference fuel (TPRFs) can match research and motor octane number of transportation fuels, they may not accurately replicate thermodynamic properties (including heat capacity ratio). This non-conformity could exhibit significant discrepancies in the end of compression temperature, thereby affecting ignition delay (τign) measurements. Another aspect of RCMs that can affect τign measurement is post compression heat loss, which depends on various RCM parameters including geometry, extent of insulation, pre-heating temperature etc. To, better understand the effects of these non-chemical kinetic parameters on τign, thermodynamic properties of a number of FACE G gasoline surrogates were calculated and simulated in a multi-zone RCM model. The problem was further investigated using a variance based analysis and individual sensitivities were calculated. This study highlights the effects on τign due to thermodynamic properties of
Dehghani, M.
2018-02-01
Making use of the suitable transformation relations, the action of three-dimensional Einstein-Maxwell-dilaton gravity theory has been obtained from that of scalar-tensor modified gravity theory coupled to the Maxwell's electrodynamics as the matter field. Two new classes of the static three-dimensional charged dilatonic black holes, as the exact solutions to the coupled scalar, electromagnetic and gravitational field equations, have been obtained in the Einstein frame. Also, it has been found that the scalar potential can be written in the form of a generalized Liouville-type potential. The conserved black hole charge and masses as well as the black entropy, temperature, and electric potential have been calculated from the geometrical and thermodynamical approaches, separately. Through comparison of the results arisen from these two alternative approaches, the validity of the thermodynamical first law has been proved for both of the new black hole solutions in the Einstein frame. Making use of the canonical ensemble method, a black hole stability or phase transition analysis has been performed. Regarding the black hole heat capacity, with the black hole charge as a constant, the points of type-1 and type-2 phase transitions have been determined. Also, the ranges of the black hole horizon radius at which the Einstein black holes are thermally stable have been obtained for both of the new black hole solutions. Then making use of the inverse transformation relations, two new classes of the string black hole solutions have been obtained from their Einstein counterpart. The thermodynamics and thermal stability of the new string black hole solutions have been investigated. It has been found that thermodynamic properties of the new charged black holes are identical in the Einstein and Jordan frames.
Batool, Javaria; Alay-e-Abbas, Syed Muhammad; Amin, Nasir
2018-04-01
The density functional theory based total energy calculations are performed to examine the effect of charge neutral and fully charged intrinsic vacancy defects on the thermodynamic, electronic, and magnetic properties of Ca3SnO antiperovskite. The chemical stability of Ca3SnO is evaluated with respect to binary compounds CaO, CaSn, and Ca2Sn, and the limits of atomic chemical potentials of Ca, Sn, and O atoms for stable synthesis of Ca3SnO are determined within the generalized gradient approximation parametrization scheme. The electronic properties of the pristine and the non-stoichiometric forms of this compound have been explored and the influence of isolated intrinsic vacancy defects (Ca, Sn, and O) on the structural, bonding, and electronic properties of non-stoichiometric Ca3SnO are analyzed. We also predict the possibility of achieving stable ferromagnetism in non-stoichiometric Ca3SnO by means of charge neutral tin vacancies. From the calculated total energies and the valid ranges of atomic chemical potentials, the formation energetics of intrinsic vacancy defects in Ca3SnO are evaluated for various growth conditions. Our results indicate that the fully charged calcium vacancies are thermodynamically stable under the permissible Sn-rich condition of stable synthesis of Ca3SnO, while tin and oxygen vacancies are found to be stable under the extreme Ca-rich condition.
International Nuclear Information System (INIS)
García-Mardones, Mónica; Barrós, Alba; Bandrés, Isabel; Artigas, Héctor; Lafuente, Carlos
2012-01-01
Highlights: ► Thermodynamic properties of an ionic liquid and an alkanol have been reported. ► The ionic liquids studied were 1-butyl-3 (or 4)-methylpyridinium tetrafluoroborate. ► The alkanols were methanol and ethanol. ► From measured data excess properties have been obtained and correlated. - Abstract: Densities and speeds of sound have been determined for the binary mixtures containing an ionic liquid (1-butyl-3-methylpyridinium tetrafluoroborate or 1-butyl-4-methylpyridinium tetrafluoroborate) and an alkanol (methanol or ethanol) over the temperature range (293.15 to 323.15) K. Excess volumes and excess isentropic compressibilities have been calculated from density and speed of sound data and correlated. All the mixtures show negative values for these excess properties. Furthermore, the isothermal (vapour + liquid) equilibrium has been measured at T = (303.15 and 323.15) K, and the corresponding activity coefficients and excess Gibbs functions have been obtained. In this case, positive excess Gibbs functions have been found. We have carried out an exhaustive interpretation of the experimental results in terms of structural and energetic effects taking also into account the thermodynamic information of pure compounds. Finally, in order to study the influence of both, the presence and the position of methyl group in the cation, we have compared the results of these systems with those obtained for the mixtures formed by 1-butylpyridinium tetrafluoroborate and methanol or ethanol.
Santos, Ana Filipa L O M; Oliveira, Juliana A S A; Ribeiro da Silva, Maria D M C; Monte, Manuel J S
2016-03-01
This work reports the experimental determination of relevant thermodynamic properties and the characterization of luminescence properties of the following polycyclic aromatic hydrocarbons (PAHs): 2,6-diethylnaphthalene, 2,6-diisopropylnaphthalene and 2,6-di-tert-butylnaphthalene. The standard (p(o) = 0.1 MPa) molar enthalpies of combustion, ΔcHm(o), of the three compounds were determined using static bomb combustion calorimetry. The vapor pressures of the crystalline phase of 2,6-diisopropylnaphthalene and 2,6-di-tert-butylnaphthalene were measured at different temperatures using the Knudsen effusion method and the vapor pressures of both liquid and crystalline phases of 2,6-diethylnaphthalene were measured by means of a static method. The temperatures and the molar enthalpies of fusion of the three compounds were determined using differential scanning calorimetry. The gas-phase molar heat capacities and absolute entropies of the three 2,6-dialkylnaphthalenes studied were determined computationally. The thermodynamic stability of the compounds in both the crystalline and gaseous phases was evaluated by the determination of the Gibbs energies of formation and compared with the ones reported in the literature for 2,6-dimethylnaphthalene. From fluorescence spectroscopy measurements, the optical properties of the compounds studied and of naphthalene were evaluated in solution and in the solid state. Copyright © 2015 Elsevier Ltd. All rights reserved.
Directory of Open Access Journals (Sweden)
Weronika Kotkowiak
2018-03-01
Full Text Available Thrombin is a serine protease that plays a crucial role in hemostasis, fibrinolysis, cell proliferation, and migration. Thrombin binding aptamer (TBA is able to inhibit the activity of thrombin molecule via binding to its exosite I. This 15-nt DNA oligonucleotide forms an intramolecular, antiparallel G-quadruplex structure with a chair-like conformation. In this paper, we report on our investigations on the influence of certain modified nucleotide residues on thermodynamic stability, folding topology, and biological properties of TBA variants. In particular, the effect of single incorporation of a novel 4-thiouracil derivative of unlocked nucleic acid (UNA, as well as single incorporation of 4-thiouridine and all four canonical UNAs, was evaluated. The studies presented herein have shown that 4-thiouridine in RNA and UNA series, as well as all four canonical UNAs, can efficiently modulate G-quadruplex thermodynamic and biological stability, and that the effect is strongly position dependent. Interestingly, TBA variants containing the modified nucleotide residues are characterized by unchanged folding topology. Thrombin time assay revealed that incorporation of certain UNA residues may improve G-quadruplex anticoagulant properties. Noteworthy, some TBA variants, characterized by decreased ability to inhibit thrombin activity, possess significant antiproliferative properties reducing the viability of the HeLa cell line even by 95% at 10 μM concentration.
Thermodynamic properties of tert-butylbenzene and 1,4-di-tert-butylbenzene
International Nuclear Information System (INIS)
Chirico, Robert D.; Steele, William V.
2009-01-01
Heat capacities, enthalpies of phase transitions, and derived thermodynamic properties over the temperature range 5 < (T/K) < 442 were determined with adiabatic calorimetry for tert-butylbenzene (TBB) {Chemical Abstracts Service registry number (CASRN) [98-06-6]} and 1,4-di-tert-butylbenzene (DTBB) {CASRN [1012-72-2]}. A crystal to plastic crystal transition very near the triple-point temperature of DTBB was observed. New vapor pressures near the triple-point temperature are also reported for DTBB for the liquid and crystal states. These new measurements, when combined with published results, allow calculation of the thermodynamic properties for the ideal gas state for both compounds. The contribution of the tert-butyl group to the entropy of the ideal gas is determined quantitatively here for the first time based on the calorimetric results over the temperature range 298.15 < (T/K) < 600. Comparisons with literature values are shown for all measured and derived properties, including entropies for the ideal gas derived from quantum chemical calculations
Thermodynamic properties of thulium and ytterbium in fused NaCl-KCl-CsCl eutectic
Energy Technology Data Exchange (ETDEWEB)
Novoselova, A., E-mail: A.Novoselova@ihte.uran.ru [Institute of High-Temperature Electrochemistry, Ural Division, Russian Academy of Science, S. Kovalevskaya Str., 22, Ekaterinburg 620990 (Russian Federation); Smolenski, V. [Institute of High-Temperature Electrochemistry, Ural Division, Russian Academy of Science, S. Kovalevskaya Str., 22, Ekaterinburg 620990 (Russian Federation)
2011-07-15
Research highlights: > Tm and Yb chloride compounds as fission products. > The investigation of electrochemical properties of lanthanides. > Determination of the apparent standard redox potentials of the couple Ln(III)/Ln(II) in fused NaCl-KCl-CsCl eutectic at (823 to 973) K. > The calculation of the basic thermodynamic properties of redox reaction in molten salt. - Abstract: This work presents the results of a study of the Tm{sup 3+}/Tm{sup 2+} and Yb{sup 3+}/Yb{sup 2+} couple redox potentials vs. Cl{sup -}/Cl{sub 2} reference electrode at the temperature range (823 to 973) K in fused NaCl-KCl-CsCl eutectic by direct potentiometric method. Initial concentrations of TmCl{sub 3} and YbCl{sub 3} in solvents did not exceed 5.0 mol%. Basic thermodynamic properties of the reactions TmCl{sub 2(l)} + 1/2 Cl{sub 2(g)} {r_reversible} TmCl{sub 3(l)} and YbCl{sub 2(l)} + 1/2 Cl{sub 2(g)} {r_reversible} YbCl{sub 3(l)} were calculated using the temperature dependencies of apparent standard potentials of the couples E{sub Tm{sup 3+}/Tm{sup 2+*}} and E{sub Yb{sup 3+}/Yb{sup 2+*}}.
Magnetic field effects of tow-leg Heisenberg antiferromagnetic ladders: Thermodynamic properties
International Nuclear Information System (INIS)
Wang Xiaoqun; Yu Lu
2000-05-01
Using the recently developed transfer-matrix renormalization group method, we have studied the thermodynamic properties of two-leg antiferromagnetic ladders in the magnetic field. Based on different behavior of magnetization, we found disordered spin liquid, Luttinger liquid, spin-polarized phases and a classical regime depending on magnetic field and temperature. Our calculations in Luttinger liquid regime suggest that both the divergence of the NMR relaxation rate and the anomalous specific heat behavior observed on Cu 2 (C 5 H 12 N 2 ) 2 Cl 4 are due to quasi-one-dimensional effect rather than three-dimensional ordering. (author)
Thermodynamic properties and equation of state of zircon ZrSiO4
International Nuclear Information System (INIS)
Mittal, R.; Chaplot, S.L.; Choudhury, N.
1998-01-01
The silicate mineral zircon is a host material for radioactive materials in the earth's crust and is a natural candidate for usage as a nuclear waste storage material. Lattice dynamical calculations have been carried out to understand its thermodynamic properties and high pressure behavior. The calculated phonon density of states, variation of phonon frequencies with pressure and equation of state are in good agreement with the available experimental data. One of the zone center optic mode involving SiO 4 rotations becomes soft at 47 GPa
The first principles study of elastic and thermodynamic properties of ZnSe
Khatta, Swati; Kaur, Veerpal; Tripathi, S. K.; Prakash, Satya
2018-05-01
The elastic and thermodynamic properties of ZnSe are investigated using thermo_pw package implemented in Quantum espresso code within the framework of density functional theory. The pseudopotential method within the local density approximation is used for the exchange-correlation potential. The physical parameters of ZnSe bulk modulus and shear modulus, anisotropy factor, Young's modulus, Poisson's ratio, Pugh's ratio and Frantsevich's ratio are calculated. The sound velocity and Debye temperature are obtained from elastic constant calculations. The Helmholtz free energy and internal energy of ZnSe are also calculated. The results are compared with available theoretical calculations and experimental data.
Vibrational analysis and thermodynamic properties of C120 nanotorus: a DFT study
International Nuclear Information System (INIS)
López-Chávez, Ernesto; Cruz-Torres, Armando; Landa Castillo-Alvarado, Fray de; Ortíz-López, Jaime; Peña-Castañeda, Yésica A.; Martínez-Magadán, José Manuel
2011-01-01
Density functional theory (DFT) computational methods are applied to a C 120 carbon nanotorus studied as an isolated molecular species, using the functional GGA PW91. This toroidal form of carbon contains five fold, six fold, and sevenfold rings. The calculated cohesive energy of the nanotorus, indicates that the ground state of this structure is energetically more stable than that of fullerene C 60 . Geometry and stability, Raman and IR vibrational analysis and thermodynamic properties have been reported and compared to the values obtained by other authors.
Energy Technology Data Exchange (ETDEWEB)
Gonzalez-Perez, Alfredo [Group of Biophysics and Interfaces, Department of Applied Physics, Faculty of Physics, University of Santiago de Compostela, E-15782 Santiago de Compostela (Spain)], E-mail: alf@usc.es; Ruso, Juan M. [Group of Biophysics and Interfaces, Department of Applied Physics, Faculty of Physics, University of Santiago de Compostela, E-15782 Santiago de Compostela (Spain); Romero, Maria J. [Department of Inorganic Chemistry, Faculty of Chemistry, University of Santiago de Compostela, E-15782 Santiago de Compostela (Spain); Blanco, Elena [Group of Biophysics and Interfaces, Department of Applied Physics, Faculty of Physics, University of Santiago de Compostela, E-15782 Santiago de Compostela (Spain); Prieto, Gerardo [Group of Biophysics and Interfaces, Department of Applied Physics, Faculty of Physics, University of Santiago de Compostela, E-15782 Santiago de Compostela (Spain); Sarmiento, Felix [Group of Biophysics and Interfaces, Department of Applied Physics, Faculty of Physics, University of Santiago de Compostela, E-15782 Santiago de Compostela (Spain)
2005-06-27
Sodium perfluoroalkyl carboxylates (CnFONa) with n = 6, 9, 10 have been studied by conductivity measurements at different temperatures. The Krafft point was determined for C9FONa and C10FONa at the highest concentration studied by measuring the temperature dependence of the specific conductivity. The critical micelle concentration (cmc) and the ionization degree of the micelle ({beta}) were estimated from conductivity vs. molality plots at different temperatures. Using these data and previous results on temperature dependence of cmc and {beta} of sodium perfluoroheptanoate and perfluorooctanoate, different models were applied to obtain the thermodynamic properties of micellization. The results are discussed in terms of alkyl chain length.
International Nuclear Information System (INIS)
Gonzalez-Perez, Alfredo; Ruso, Juan M.; Romero, Maria J.; Blanco, Elena; Prieto, Gerardo; Sarmiento, Felix
2005-01-01
Sodium perfluoroalkyl carboxylates (CnFONa) with n = 6, 9, 10 have been studied by conductivity measurements at different temperatures. The Krafft point was determined for C9FONa and C10FONa at the highest concentration studied by measuring the temperature dependence of the specific conductivity. The critical micelle concentration (cmc) and the ionization degree of the micelle (β) were estimated from conductivity vs. molality plots at different temperatures. Using these data and previous results on temperature dependence of cmc and β of sodium perfluoroheptanoate and perfluorooctanoate, different models were applied to obtain the thermodynamic properties of micellization. The results are discussed in terms of alkyl chain length
Thermodynamic properties of a quantum group boson gas GLp,q(2)
International Nuclear Information System (INIS)
Jellal, Ahmed
2000-10-01
An approach is proposed enabling to effectively describe the behaviour of a bosonic system. The approach uses the quantum group GL p,q (2) formalism. In effect, considering a bosonic Hamiltonian in terms of the GL p,q (2) generators, it is shown that its thermodynamic properties are connected to deformation parameters p and q. For instance, the average number of particles and the pressure have been computed. If p is fixed to be the same value for q, our approach coincides perfectly with some results developed recently in this subject. The ordinary results, of the present system, can be found when we take the limit p = q = 1. (author)
A comparative study of thermodynamic properties of binary mixtures containing alkynes
International Nuclear Information System (INIS)
Falconieri, Danilo; Marongiu, Bruno; Piras, Alessandra; Porcedda, Silvia
2004-01-01
Literature data on molar excess enthalpies (H E ) and molar excess Gibbs energies (G E ) of linear alkynes+n-alkanes, cycloalkanes, benzene or tetrachloromethane are treated in the framework of DISQUAC, an extended quasichemical group-contribution theory. The systems are characterized by three types of contact surfaces: acetylenic (C-C group), aliphatic (CH 3 or CH 2 groups), cycloaliphatic (c-CH 2 group), aromatic (C 6 H 6 group) and chlorine (CCl 4 group). Using a limited number of adjusted contact interchange energies parameters, the model provides a fairly consistent description of the thermodynamic properties as a function of concentration. The model may serve to predict missing data
Thermodynamic properties of a solid exhibiting the energy spectrum given by the logistic map
International Nuclear Information System (INIS)
Curado, E.M.F.
2000-05-01
We show that the infinite-dimensional representation of the recently introduced Logistic algebra can be interpreted as a non-trivial generalization of the Heisenberg or oscillator algebra. This allows to construct a quantum Hamiltonian having the energy energy spectrum given by the logistic map. We analyze the Hamiltonian of a solid whose collective modes of vibrations are described by this generalized oscillator and compute the thermodynamic properties of the model in the two-cycle and γ3.6785 chaotic region of the logistic map. (author)
Moustafa, Sabry Gad Al-Hak Mohammad
Molecular simulation (MS) methods (e.g. Monte Carlo (MC) and molecular dynamics (MD)) provide a reliable tool (especially at extreme conditions) to measure solid properties. However, measuring them accurately and efficiently (smallest uncertainty for a given time) using MS can be a big challenge especially with ab initio-type models. In addition, comparing with experimental results through extrapolating properties from finite size to the thermodynamic limit can be a critical obstacle. We first estimate the free energy (FE) of crystalline system of simple discontinuous potential, hard-spheres (HS), at its melting condition. Several approaches are explored to determine the most efficient route. The comparison study shows a considerable improvement in efficiency over the standard MS methods that are known for solid phases. In addition, we were able to accurately extrapolate to the thermodynamic limit using relatively small system sizes. Although the method is applied to HS model, it is readily extended to more complex hard-body potentials, such as hard tetrahedra. The harmonic approximation of the potential energy surface is usually an accurate model (especially at low temperature and large density) to describe many realistic solid phases. In addition, since the analysis is done numerically the method is relatively cheap. Here, we apply lattice dynamics (LD) techniques to get the FE of clathrate hydrates structures. Rigid-bonds model is assumed to describe water molecules; this, however, requires additional orientation degree-of-freedom in order to specify each molecule. However, we were able to efficiently avoid using those degrees of freedom through a mathematical transformation that only uses the atomic coordinates of water molecules. In addition, the proton-disorder nature of hydrate water networks adds extra complexity to the problem, especially when extrapolating to the thermodynamic limit is needed. The finite-size effects of the proton disorder contribution is
International Nuclear Information System (INIS)
Khaleque, M.A.; Bhuiyan, G.M.; Rashid, R.I.M.A.
1998-01-01
Thermodynamic properties such as entropy, specific heat capacity at constant pressure and isothermal compressibility have been calculated for liquid 3d, 4d and 5d transition metals near melting temperature. The hard sphere diameter for all such systems is estimated from the potential profile generated from the Wills and Harrison's prescription using linearized WCA theory of liquid. Evaluated values of entropy and specific heat capacity are found to be in good agreement with the experimental data. Transport property like shear viscosity for these liquid metals is obtained using the same potential profile. Lack of experimental data at melting temperatures hampers detailed comparison for all such systems. However, for the case of transport property, the results obtained are found to compare qualitatively well with the available experimental data. (author)
Internet calculations of thermodynamic properties of substances: Some problems and results
International Nuclear Information System (INIS)
Ustyuzhanin, E E; Ochkov, V F; Shishakov, V V; Rykov, S V
2016-01-01
Internet resources (databases, web sites and others) on thermodynamic properties R = ( p,T,s ,...) of technologically important substances are analyzed. These databases put online by a number of organizations (the Joint Institute for High Temperatures of the Russian Academy of Sciences, Standartinform, the National Institute of Standards and Technology USA, the Institute for Thermal Physics of the Siberian Branch of the Russian Academy of Sciences, etc ) are investigated. Software codes are elaborated in the work in forms of “client functions” those have such characteristics: (i) they are placed on a remote server, (ii) they serve as open interactive Internet resources. A client can use them for a calculation of R properties of substances. “Complex client functions” are considered. They are focused on sharing (i) software codes elaborated to design of power plants (PP) and (ii) client functions those can calculate R properties of working fluids for PP. (paper)
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.
Directory of Open Access Journals (Sweden)
Andrej Kastrin
Full Text Available Concept associations can be represented by a network that consists of a set of nodes representing concepts and a set of edges representing their relationships. Complex networks exhibit some common topological features including small diameter, high degree of clustering, power-law degree distribution, and modularity. We investigated the topological properties of a network constructed from co-occurrences between MeSH descriptors in the MEDLINE database. We conducted the analysis on two networks, one constructed from all MeSH descriptors and another using only major descriptors. Network reduction was performed using the Pearson's chi-square test for independence. To characterize topological properties of the network we adopted some specific measures, including diameter, average path length, clustering coefficient, and degree distribution. For the full MeSH network the average path length was 1.95 with a diameter of three edges and clustering coefficient of 0.26. The Kolmogorov-Smirnov test rejects the power law as a plausible model for degree distribution. For the major MeSH network the average path length was 2.63 edges with a diameter of seven edges and clustering coefficient of 0.15. The Kolmogorov-Smirnov test failed to reject the power law as a plausible model. The power-law exponent was 5.07. In both networks it was evident that nodes with a lower degree exhibit higher clustering than those with a higher degree. After simulated attack, where we removed 10% of nodes with the highest degrees, the giant component of each of the two networks contains about 90% of all nodes. Because of small average path length and high degree of clustering the MeSH network is small-world. A power-law distribution is not a plausible model for the degree distribution. The network is highly modular, highly resistant to targeted and random attack and with minimal dissortativity.
Thermodynamical properties of dark energy with the equation of state ω=ω0+ω1z
International Nuclear Information System (INIS)
Zhang Yongping; Yi Zelong; Zhang Tongjie; Liu Wenbiao
2008-01-01
The thermodynamical properties of dark energy are usually investigated with the equation of state ω=ω 0 +ω 1 z. Recent observations show that our Universe is accelerating, and the apparent horizon and the event horizon vary with redshift z. Because definitions of the temperature and entropy of a black hole are used to describe the two horizons of the Universe, we examine the thermodynamical properties of the Universe, which is enveloped by the apparent horizon and the event horizon, respectively. We show that the first and the second laws of thermodynamics inside the apparent horizon in any redshift are satisfied, while they are broken down inside the event horizon in some redshifts. Therefore, the apparent horizon for the Universe may be the boundary of thermodynamical equilibrium for the Universe like the event horizon for a black hole
Special relativity - the foundation of macroscopic physics
International Nuclear Information System (INIS)
Dixon, W.G.
1978-01-01
This book aims to show that an understanding of the basic laws of macroscopic systems can be gained more easily within relativistic physics than within Newtonian physics. The unity of dynamics, thermodynamics and electromagnetism under the umbrella of special relativity is examined under chapter headings entitled: the physics of space and time, affine spaces in mathematics and physics, foundations of dynamics, relativistic simple fluids, and, electrodynamics of polarizable fluids. (U.K.)
Thermodynamic modeling of the power plant based on the SOFC with internal steam reforming of methane
International Nuclear Information System (INIS)
Ivanov, Peter
2007-01-01
Mathematical model based on the thermodynamic modeling of gaseous mixtures is developed for SOFC with internal steam reforming of methane. Macroscopic porous-electrode theory, including non-linear kinetics and gas-phase diffusion, is used to calculate the reforming reaction and the concentration polarization. Provided the data concerning properties and costs of materials the model is fit for wide range of parametric analysis of thermodynamic cycles including SOFC
Searching for the nanoscopic–macroscopic boundary
Energy Technology Data Exchange (ETDEWEB)
Velásquez, E.A. [GICM and GES Groups, Instituto de Física-FCEN, Universidad de Antioquia UdeA, Calle 70 No. 52-21 Medellín (Colombia); Grupo de Investigación en Modelamiento y Simulación Computacional, Universidad de San Buenaventura Sec. Medellín, A.A. 5222, Medellín (Colombia); Altbir, D. [Departamento de Física, Universidad de Santiago de Chile (USACH), CEDENNA, Santiago (Chile); Mazo-Zuluaga, J. [GICM and GES Groups, Instituto de Física-FCEN, Universidad de Antioquia UdeA, Calle 70 No. 52-21 Medellín (Colombia); Duque, L.F. [GICM and GES Groups, Instituto de Física-FCEN, Universidad de Antioquia UdeA, Calle 70 No. 52-21 Medellín (Colombia); Grupo de Física Teórica, Aplicada y Didáctica, Facultad de Ciencias Exactas y Aplicadas Instituto Tecnológico Metropolitano, Medellín (Colombia); Mejía-López, J., E-mail: jmejia@puc.cl [Facultad de Física, Pontificia Universidad Católica de Chile, CEDENNA, Santiago (Chile)
2013-12-15
Several studies have focused on the size-dependent properties of elements, looking for a unique definition of the nanoscopic–macroscopic boundary. By using a novel approach consisting of an energy variational method combined with a quantum Heisenberg model, here we address the size at which the ordering temperature of a magnetic nanoparticle reaches its bulk value. We consider samples with sizes in the range 1–500 nm, as well as several geometries and crystalline lattices and observe that, contrarily to what is commonly argued, the nanoscopic-microscopic boundary depends on both factors: shape and crystalline structure. This suggests that the surface-to-volume ratio is not the unique parameter that defines the behavior of a nanometric sample whenever its size increases reaching the bulk dimension. Comparisons reveal very good agreement with experimental evidence with differences less than 2%. Our results have broad implications for practical issues in measurements on systems at the nanometric scale. - Highlights: • A novel quantum-Heisenberg variational energy method is implemented. • The asymptotic behavior toward the thermodynamic limit is explored. • An important dependence of the nano-bulk boundary on the geometry is found. • And also an important dependence on the crystalline lattice. • We obtain a very good agreement with experimental evidence with differences <2%.
Iglesias, Daniel; Senokos, Evgeny; Alemán, Belén; Cabana, Laura; Navío, Cristina; Marcilla, Rebeca; Prato, Maurizio; Vilatela, Juan J; Marchesan, Silvia
2018-02-14
The assembly of aligned carbon nanotubes (CNTs) into fibers (CNTFs) is a convenient approach to exploit and apply the unique physico-chemical properties of CNTs in many fields. CNT functionalization has been extensively used for its implementation into composites and devices. However, CNTF functionalization is still in its infancy because of the challenges associated with preservation of CNTF morphology. Here, we report a thorough study of the gas-phase functionalization of CNTF assemblies using ozone which was generated in situ from a UV source. In contrast with liquid-based oxidation methods, this gas-phase approach preserves CNTF morphology, while notably increasing its hydrophilicity. The functionalized material is thoroughly characterized by Raman spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, and scanning electron microscopy. Its newly acquired hydrophilicity enables CNTF electrochemical characterization in aqueous media, which was not possible for the pristine material. Through comparison of electrochemical measurements in aqueous electrolytes and ionic liquids, we decouple the effects of functionalization on pseudocapacitive reactions and quantum capacitance. The functionalized CNTF assembly is successfully used as an active material and a current collector in all-solid supercapacitor flexible devices with an ionic liquid-based polymer electrolyte.
International Nuclear Information System (INIS)
Matsui, T.; Ohse, R.W.
1986-01-01
Thermodynamic properties such as vapour pressures, heat capacities and enthalpies of formation for UN(s), PuN(s) and (U, Pu)N(s) are critically evaluated. The equations of the vapour pressures and the heat capacities for the three nitrides are assessed. Thermal functions, and thermodynamic functions for the formation of UN(s), PuN(s) and (U, Pu)N(s), are calculated
A test of systematic coarse-graining of molecular dynamics simulations: Thermodynamic properties
Fu, Chia-Chun; Kulkarni, Pandurang M.; Scott Shell, M.; Gary Leal, L.
2012-10-01
Coarse-graining (CG) techniques have recently attracted great interest for providing descriptions at a mesoscopic level of resolution that preserve fluid thermodynamic and transport behaviors with a reduced number of degrees of freedom and hence less computational effort. One fundamental question arises: how well and to what extent can a "bottom-up" developed mesoscale model recover the physical properties of a molecular scale system? To answer this question, we explore systematically the properties of a CG model that is developed to represent an intermediate mesoscale model between the atomistic and continuum scales. This CG model aims to reduce the computational cost relative to a full atomistic simulation, and we assess to what extent it is possible to preserve both the thermodynamic and transport properties of an underlying reference all-atom Lennard-Jones (LJ) system. In this paper, only the thermodynamic properties are considered in detail. The transport properties will be examined in subsequent work. To coarse-grain, we first use the iterative Boltzmann inversion (IBI) to determine a CG potential for a (1-ϕ)N mesoscale particle system, where ϕ is the degree of coarse-graining, so as to reproduce the radial distribution function (RDF) of an N atomic particle system. Even though the uniqueness theorem guarantees a one to one relationship between the RDF and an effective pairwise potential, we find that RDFs are insensitive to the long-range part of the IBI-determined potentials, which provides some significant flexibility in further matching other properties. We then propose a reformulation of IBI as a robust minimization procedure that enables simultaneous matching of the RDF and the fluid pressure. We find that this new method mainly changes the attractive tail region of the CG potentials, and it improves the isothermal compressibility relative to pure IBI. We also find that there are optimal interaction cutoff lengths for the CG system, as a function of
Thermodynamic properties of 2,7-di-tert-butylfluorene – An experimental and computational study
International Nuclear Information System (INIS)
Oliveira, Juliana A.S.A.; Freitas, Vera L.S.; Notario, Rafael; Ribeiro da Silva, Maria D.M.C.; Monte, Manuel J.S.
2016-01-01
Highlights: • Enthalpies and Gibbs energies of formation of 2,7-di-tert-butylfluorene were determined. • Vapour pressures were measured at different temperatures. • Phase transition thermodynamic properties were determined. - Abstract: This work presents a comprehensive experimental and computational study of the thermodynamic properties of 2,7-di-tert-butylfluorene. The standard (p"o = 0.1 MPa) molar enthalpy of formation in the crystalline phase was derived from the standard molar energy of combustion, measured by static bomb combustion calorimetry. The enthalpies and temperatures of transition between condensed phases were determined from DSC experiments. The vapour pressures of the crystalline and liquid phases were measured between (349.14 and 404.04) K, using two different experimental methods. From these results the standard molar enthalpies, entropies and Gibbs energies of sublimation and of vaporization were derived. The enthalpy of sublimation was also determined using Calvet microcalorimetry. The thermodynamic stability of 2,7-di-tert-butylfluorene in the crystalline and gaseous phases was evaluated by the determination of the standard Gibbs energies of formation, at the temperature 298.15 K, and compared with the ones reported in the literature for fluorene. A computational study at the G3(MP2)//B3LYP and G3 levels has been carried out. A conformational analysis has been performed and the enthalpy of formation of 2,7-di-tert-butylfluorene has been calculated, using atomization and isodesmic reactions. The calculated enthalpies of formation have been compared to the experimental values.
Thermodynamic properties and entropy scaling law for diffusivity in soft spheres.
Pieprzyk, S; Heyes, D M; Brańka, A C
2014-07-01
The purely repulsive soft-sphere system, where the interaction potential is inversely proportional to the pair separation raised to the power n, is considered. The Laplace transform technique is used to derive its thermodynamic properties in terms of the potential energy and its density derivative obtained from molecular dynamics simulations. The derived expressions provide an analytic framework with which to explore soft-sphere thermodynamics across the whole softness-density fluid domain. The trends in the isochoric and isobaric heat capacity, thermal expansion coefficient, isothermal and adiabatic bulk moduli, Grüneisen parameter, isothermal pressure, and the Joule-Thomson coefficient as a function of fluid density and potential softness are described using these formulas supplemented by the simulation-derived equation of state. At low densities a minimum in the isobaric heat capacity with density is found, which is a new feature for a purely repulsive pair interaction. The hard-sphere and n = 3 limits are obtained, and the low density limit specified analytically for any n is discussed. The softness dependence of calculated quantities indicates freezing criteria based on features of the radial distribution function or derived functions of it are not expected to be universal. A new and accurate formula linking the self-diffusion coefficient to the excess entropy for the entire fluid softness-density domain is proposed, which incorporates the kinetic theory solution for the low density limit and an entropy-dependent function in an exponential form. The thermodynamic properties (or their derivatives), structural quantities, and diffusion coefficient indicate that three regions specified by a convex, concave, and intermediate density dependence can be expected as a function of n, with a narrow transition region within the range 5 < n < 8.
Thermodynamic theory of equilibrium fluctuations
International Nuclear Information System (INIS)
Mishin, Y.
2015-01-01
The postulational basis of classical thermodynamics has been expanded to incorporate equilibrium fluctuations. The main additional elements of the proposed thermodynamic theory are the concept of quasi-equilibrium states, a definition of non-equilibrium entropy, a fundamental equation of state in the entropy representation, and a fluctuation postulate describing the probability distribution of macroscopic parameters of an isolated system. Although these elements introduce a statistical component that does not exist in classical thermodynamics, the logical structure of the theory is different from that of statistical mechanics and represents an expanded version of thermodynamics. Based on this theory, we present a regular procedure for calculations of equilibrium fluctuations of extensive parameters, intensive parameters and densities in systems with any number of fluctuating parameters. The proposed fluctuation formalism is demonstrated by four applications: (1) derivation of the complete set of fluctuation relations for a simple fluid in three different ensembles; (2) fluctuations in finite-reservoir systems interpolating between the canonical and micro-canonical ensembles; (3) derivation of fluctuation relations for excess properties of grain boundaries in binary solid solutions, and (4) derivation of the grain boundary width distribution for pre-melted grain boundaries in alloys. The last two applications offer an efficient fluctuation-based approach to calculations of interface excess properties and extraction of the disjoining potential in pre-melted grain boundaries. Possible future extensions of the theory are outlined.
One Antimatter— Two Possible Thermodynamics
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Alexander Y. Klimenko
2014-02-01
Full Text Available Conventional thermodynamics, which is formulated for our world populated by radiation and matter, can be extended to describe physical properties of antimatter in two mutually exclusive ways: CP-invariant or CPT-invariant. Here we refer to invariance of physical laws under charge (C, parity (P and time reversal (T transformations. While in quantum field theory CPT invariance is a theorem confirmed by experiments, the symmetry principles applied to macroscopic phenomena or to the whole of the Universe represent only hypotheses. Since both versions of thermodynamics are different only in their treatment of antimatter, but are the same in describing our world dominated by matter, making a clear experimentally justified choice between CP invariance and CPT invariance in context of thermodynamics is not possible at present. This work investigates the comparative properties of the CP- and CPT-invariant extensions of thermodynamics (focusing on the latter, which is less conventional than the former and examines conditions under which these extensions can be experimentally tested.
Thermodynamic properties for applications in chemical industry via classical force fields.
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.
International Nuclear Information System (INIS)
Yang, Peng; Du, Shichao; Qin, Yujia; Zhao, Kaifei; Li, Kangli; Hou, Baohong; Gong, Junbo
2016-01-01
Highlights: • The solubility data of pyraclostrobin in pure and binary solvents were determined and correlated. • The theory of solubility parameter was used to explain the cosolvency in binary solvents. • A modified mixing rule was proposed to calculate the solubility parameter of binary solvents. • The dissolution thermodynamic properties were calculated and discussed. - Abstract: The solubility of pyraclostrobin in five pure solvents and two binary solvent mixtures was measured from 283.15 K to 308.15 K using a static analytical method. Solubility in five pure solvents was well correlated by the modified Apelblat equation and Wilson model. While the CNIBS/R–K model was applied to correlate the solubility in two binary solvent mixtures, the correlation showed good agreement with experimental results. The solubility of pyraclostrobin reaches its maximum value at a certain cyclohexane mole fraction in the two binary solvent mixtures. The solubility parameter of pyraclostrobin was calculated by the Fedors method and a new modified mixing rule with preferable applicability was proposed to determine the solubility parameter of solvents. Then the co-solvency in the binary solvent mixtures can be explained based on the obtained solubility parameters. In a addition, the dissolution thermodynamic properties were calculated from the experimental values using the Wilson model.
First principal studya of structural, electronic and thermodynamic properties of KTaO3-perovskite.
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Hiadsi S.
2013-03-01
Full Text Available The results of first-principles theoretical study of structural, elastic, electronic and thermodynamic properties of KTaO3 compound, have been performed using the full-potential linear augmented plane-wave method plus local orbitals (FP-APW+lo as implemented in the Wien2k code. The exchange-correlation energy, is treated in generalized gradient approximation (GGA using the Perdew–Burke–Ernzerhof (PBE96 and PBEsol, Perdew 2008 parameterization. Also we have used the Engel-Vosko GGA optimizes the corresponding potential for band structure calculations. The calculated equilibrium parameter is in good agreement with other works. The elastic constants were calculated by using the Mehl method. The electronic band structure of this compound has been calculated using the Angel-Vosko (EV generalized gradient approximation (GGA for the exchange correlation potential. We deduced that KTaO3-perovskite exhibit an indirect from R to Γ point. To complete the fundamental characterization of KTaO3 material we have analyzed the thermodynamic properties using the quasi-harmonic Debye model.
International Nuclear Information System (INIS)
Lima, R.A.T. de.
1982-01-01
Within the variational method in statistical mechanics, dynamical and thermodynamical properties of anharmonic crystal are discussed, in particular the thermal behavior of the crystalline expasion, phonons spectrum, specific heat and Debye-Weller factor (which satisfctorily describes the experimental data). Through the temperature dependent Green functions framework, dynamical and thermodynamical properties associated with the spin-Peierls transition in the magnetostrictive XY model (with one-dimensional magnetic interactions but structurally three-dimensional) are also discussed. Emphasis is given to the influence of an external magnetic field (along the z-axis) on the structural order parameter, phase diagram, specific heat, magnetization, magnetic susceptibility and phonons spectrun (acoustic and optic branches). Results are extended and new ons are exhibited such as: a) a structural Lifshitz point, which separates the uniform (U), dimerized (D) and modulated (M) phases in the T-H phase diagram; b) another special point is detected for high magnetic fields; c) the D-M first-order frontier and the metastability limits are obtained; d) for high elastic constants, fixed temperature and increasing magnetic field, the unusual sequence non uniform-uniform - non uniform-uniform is possible; e) the thermal dependence of the sound velocity presents a gap at the critical temperature. The present results have provided a quite satisfactory qualitative (and partially quantitative) description of the experiments on the TTF-BDT and MEM-(TCNQ) 2 ; this fact enables us to hope that several of our predictions indeed occur in nature. (Author) [pt
Kawai, Soshi
2014-11-01
In this talk, we first propose a numerical strategy that is robust and high-order accurate for enabling to simulate transcritical flows at supercritical pressures under abrupt variations in thermodynamic properties due to the real fluid effects. The method is based on introducing artificial density diffusion in a physically-consistent manner in order to capture the steep variation of thermodynamic properties in transcritical conditions robustly, while solving a pressure evolution equation to achieve pressure equilibrium at the transcritical interfaces. We then discuss the direct numerical simulation (DNS) of transcritical heated turbulent boundary layers on a zero-pressure-gradient flat plate at supercritical pressures. To the best of my knowledge, the present DNS is the first DNS of zero-pressure-gradient flat-plate transcritical turbulent boundary layer. The turbulent kinetic budget indicates that the compressibility effects (especially, pressure-dilatation correlation) are not negligible at the transcritical conditions even if the flow is subsonic. The unique and interesting interactions between the real fluid effects and wall turbulence, and their turbulence statistics, which have never been seen in the ideal-fluid turbulent boundary layers, are also discussed. This work was supported in part by Japan Society for the Promotion of Science (JSPS) Grant-in-Aid for Young Scientists (A) KAKENHI 26709066 and the JAXA International Top Young Fellowship Program.
Thermodynamic properties of liquid silver-antimony alloys determined from emf measurements
International Nuclear Information System (INIS)
Krzyzak, Agnieszka; Fitzner, Krzysztof
2004-01-01
The thermodynamic properties of the liquid Ag-Sb alloys were determined using solid oxide galvanic cells with zirconia electrolyte. The emfs of the cells:Ag x Sb (1-x), Sb 2 O 3 /O 2- /airwere measured in the temperatures range 950-1100K in the whole range of the alloy compositions.First, the Gibbs free energy of formation of liquid Sb 2 O 3 from pure elements was derived:ΔG o f(Sb2O3) (J/mol)=-687100+243.23T.Next, the activities of antimony were measured as a function of the alloy compositions, x. Redlich-Kister polynomial expansion was used to describe the thermodynamic properties of the liquid phase. From the model equations the limiting value of the logarithm of activity coefficient of antimony in silver was obtained as a function of temperature:lnγ Sb 0 =-3812.5/T+0.4112.The obtained results were compared with the experimental values reported in the literature
Study of thermodynamics and electronics properties of hybrids of substituted Haucke compounds
International Nuclear Information System (INIS)
Crivello, J.C.
2005-06-01
This manuscript presents a combined experimental and theoretical contribution to the study of the substituted Haucke phase AB5. These compounds can reversibly absorb hydrogen under conditions of pressure and temperature satisfactory for many technological applications including hydrogen storage. The thermodynamic characterization of the solid-gas reaction was carried out for mono and poly-substituted compounds. In the respect of good conditions of growth (decomposition) of the hydride phase, we sought to determine the thermodynamic trajectories allowed during some various transformations. The experimental results showed that the rate of transformation and the hierarchy of the return-points memory are the only parameters allowing to draw a general law related to the irreversible character of hysteresis. These systems evolve in 'static' mode, independent of the time and whatever the nature of host materials. Moreover, the effect of substitution elements on electronic properties has been studied using ab initio band structure calculations for the ANi 5 (A=La, Y, Ca) and LaNi 5-x M x compounds, where M is an element of the type s-p (Al, Si, Ge, Sn), of type s (Cu), or a transition metal (Mn, Fe, Co). While dissociating the structural effects, the role of the chemical interaction with hydrogen was analyzed. These results made it possible to identify the factors which control the stability of the hydrides and their maximum absorption capacity. The bulk moduli of these materials were calculated and their variation was discussed in relation to the properties of hydrogen absorption. (author)
Musari, A. A.; Orukombo, S. A.
2018-03-01
Barium chalcogenides are known for their high-technological importance and great scientific interest. Detailed studies of their elastic, mechanical, dynamical and thermodynamic properties were carried out using density functional theory and plane-wave pseudo potential method within the generalized gradient approximation. The optimized lattice constants were in good agreement when compared with experimental data. The independent elastic constants, calculated from a linear fit of the computed stress-strain function, were used to determine the Young’s modulus (E), bulk modulus (B), shear modulus (G), Poisson’s ratio (σ) and Zener’s anisotropy factor (A). Also, the Debye temperature and sound velocities for barium chalcogenides were estimated from the three independent elastic constants. The calculations of phonon dispersion showed that there are no negative frequencies throughout the Brillouin zone. Hence barium chalcogenides have dynamically stable NaCl-type crystal structure. Finally, their thermodynamic properties were calculated in the temperature range of 0-1000 K and their constant-volume specific heat capacities at room-temperature were reported.
International Nuclear Information System (INIS)
Davoodi, J.; Ahmadi, M.; Rafii-Tabar, H.
2010-01-01
Molecular dynamics (MD) simulations have been performed to investigate the thermodynamic and mechanical properties of Cu-x% Pd (at%) random alloy, as well as those of the Cu 3 Pd and CuPd 3 ordered alloys, in the temperature range from 200 K up to the melting point. The quantum Sutton-Chen (Q-SC) many-body interatomic potentials have been used to describe the energetics of the Cu and Pd pure metals, and a standard mixing rule has been employed to obtain the potential parameters for the mixed (alloy) states. We have computed the variation of the melting temperature with the concentration of Pd. Furthermore, the variation of the cohesive energy, the order parameter, the thermal expansion coefficient, the density, the isobaric heat capacity, the bulk modulus, and the elastic stiffness constants were also calculated at different temperatures and concentrations for these materials. The computed variations of the thermodynamic and mechanical properties with temperature are fitted to a polynomial function. Our computed results show good agreement with other computational simulations, as well as with the experimental results where they have been available.
Energy Technology Data Exchange (ETDEWEB)
Davoodi, J., E-mail: jdavoodi@znu.ac.ir [Departmant of Physics, University of Zanjan, P.O. Box 45371-38111, Zanjan (Iran, Islamic Republic of); Ahmadi, M. [Departmant of Physics, University of Zanjan, P.O. Box 45371-38111, Zanjan (Iran, Islamic Republic of); Rafii-Tabar, H. [Department of Medical Physics and Biomedical Engineering and Research Center for Medical Nanotechnology and Tissue Engineering, Shahid Beheshti University of Medical Sciences, Evin, Tehran (Iran, Islamic Republic of); Computational Physical Sciences Research Laboratory, Department of Nano-Science, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of)
2010-06-25
Molecular dynamics (MD) simulations have been performed to investigate the thermodynamic and mechanical properties of Cu-x% Pd (at%) random alloy, as well as those of the Cu{sub 3}Pd and CuPd{sub 3} ordered alloys, in the temperature range from 200 K up to the melting point. The quantum Sutton-Chen (Q-SC) many-body interatomic potentials have been used to describe the energetics of the Cu and Pd pure metals, and a standard mixing rule has been employed to obtain the potential parameters for the mixed (alloy) states. We have computed the variation of the melting temperature with the concentration of Pd. Furthermore, the variation of the cohesive energy, the order parameter, the thermal expansion coefficient, the density, the isobaric heat capacity, the bulk modulus, and the elastic stiffness constants were also calculated at different temperatures and concentrations for these materials. The computed variations of the thermodynamic and mechanical properties with temperature are fitted to a polynomial function. Our computed results show good agreement with other computational simulations, as well as with the experimental results where they have been available.
Energy Technology Data Exchange (ETDEWEB)
Virot, F., E-mail: francois.virot@irsn.fr; Barrachin, M.; Souvi, S.; Cantrel, L.
2014-10-15
Highlights: • Standard enthalpies of formation of BeH, BeH{sub 2}, BeOH, Be(OH){sub 2} have been calculated. • The impact of hydrogen isotopy on thermodynamic properties has been shown. • Speciation in the vacuum vessel shows that the main tritiated species is tritiated steam. • Beryllium hydroxide and hydride could exist during an accidental event. - Abstract: By quantum chemistry calculations, we have evaluated the standard enthalpies of formation of some gaseous species of the Be-O-H chemical system: BeH, BeH{sub 2}, BeOH, Be(OH){sub 2} for which the values in the referenced thermodynamic databases (NIST-JANAF [1] or COACH [2]) were, due to the lack of experimental data, estimated or reported with a large uncertainty. Comparison between post-HF, DFT approaches and available experimental data allows validation of the ability of an accurate exchange-correlation functional, VSXC, to predict the thermo-chemical properties of the beryllium species of interest. Deviation of enthalpy of formation induced by changes in hydrogen isotopy has been also calculated. From these new theoretically determinated data, we have calculated the chemical speciation in conditions simulating an accident of water ingress in the vacuum vessel of ITER.
First-principles calculations on thermodynamic properties of BaTiO3 rhombohedral phase.
Bandura, Andrei V; Evarestov, Robert A
2012-07-05
The calculations based on the linear combination of atomic orbitals have been performed for the low-temperature phase of BaTiO(3) crystal. Structural and electronic properties, as well as phonon frequencies were obtained using hybrid PBE0 exchange-correlation functional. The calculated frequencies and total energies at different volumes have been used to determine the equation of state and thermal contribution to the Helmholtz free energy within the quasiharmonic approximation. For the first time, the bulk modulus, volume thermal expansion coefficient, heat capacity, and Grüneisen parameters in BaTiO(3) rhombohedral phase have been estimated at zero pressure and temperatures form 0 to 200 K, based on the results of first-principles calculations. Empirical equation has been proposed to reproduce the temperature dependence of the calculated quantities. The agreement between the theoretical and experimental thermodynamic properties was found to be satisfactory. Copyright © 2012 Wiley Periodicals, Inc.
Thermodynamic and transport properties of nitrogen fluid: Molecular theory and computer simulations
Eskandari Nasrabad, A.; Laghaei, R.
2018-04-01
Computer simulations and various theories are applied to compute the thermodynamic and transport properties of nitrogen fluid. To model the nitrogen interaction, an existing potential in the literature is modified to obtain a close agreement between the simulation results and experimental data for the orthobaric densities. We use the Generic van der Waals theory to calculate the mean free volume and apply the results within the modified Cohen-Turnbull relation to obtain the self-diffusion coefficient. Compared to experimental data, excellent results are obtained via computer simulations for the orthobaric densities, the vapor pressure, the equation of state, and the shear viscosity. We analyze the results of the theory and computer simulations for the various thermophysical properties.
First-Principle Calculations for Elastic and Thermodynamic Properties of Diamond
International Nuclear Information System (INIS)
Fu Zhijian; Chen Xiangrong; Gou Qingquan; Ji Guangfu
2009-01-01
The elastic constants and thermodynamic properties of diamond are investigated by using the CRYSTAL03 program. The lattice parameters, the bulk modulus, the heat capacity, the Grueneisen parameter, and the Debye temperature are obtained. The results are in good agreement with the available experimental and theoretical data. Moreover, the relationship between V/V 0 and pressure, the elastic constants under high pressure are successfully obtained. Especially, the elastic constants of diamond under high pressure are firstly obtained theoretically. At the same time, the variations of the thermal expansion α with pressure P and temperature Tare obtained systematically in the ranges of 0-870 GPa and 0-1600 K. (condensed matter: electronic structure, electrical, magnetic, and optical properties)
International Nuclear Information System (INIS)
Murphy, R.W.
1992-01-01
Magneto-thermodynamic property characterizations were selected, adapted, and compared to material property data for gadolinium gallium garnet in the temperature range 4--40 K and magnetic field range 0--6 T. The most appropriate formulations were incorporated into a model in which methods similar to those previously developed for other materials and temperature ranges were used to make limitation and relative performance assessments of Carnot, ideal regenerative, and pseudo-constant field regenerative cycles. Analysis showed that although Carnot cycle limitations on available temperature lift for gadolinium gallium garnet are not as severe as those for materials previously examined, substantial improvements in cooling capacity/temperature lift combinations can be achieved using regenerative cycles within specified fields limits if significant loss mechanisms are mitigated
Directory of Open Access Journals (Sweden)
Samah Al-Qaisi
Full Text Available First-principles investigations of the Terbium oxide TbO are performed on structural, elastic, mechanical and thermodynamic properties. The investigations are accomplished by employing full potential augmented plane wave FP-LAPW method framed within density functional theory DFT as implemented in the WIEN2k package. The exchange-correlation energy functional, a part of the total energy functional, is treated through Perdew Burke Ernzerhof scheme of the Generalized Gradient Approximation PBEGGA. The calculations of the ground state structural parameters, like lattice constants a0, bulk moduli B and their pressure derivative B′ values, are done for the rock-salt RS, zinc-blende ZB, cesium chloride CsCl, wurtzite WZ and nickel arsenide NiAs polymorphs of the TbO compound. The elastic constants (C11, C12, C13, C33, and C44 and mechanical properties (Young’s modulus Y, Shear modulus S, Poisson’s ratio σ, Anisotropic ratio A and compressibility β, were also calculated to comprehend its potential for valuable applications. From our calculations, the RS phase of TbO compound was found strongest one mechanically amongst the studied cubic structures whereas from hexagonal phases, the NiAs type structure was found stronger than WZ phase of the TbO. To analyze the ductility of the different structures of the TbO, Pugh’s rule (B/SH and Cauchy pressure (C12–C44 approaches are used. It was found that ZB, CsCl and WZ type structures of the TbO were of ductile nature with the obvious dominance of the ionic bonding while RS and NiAs structures exhibited brittle nature with the covalent bonding dominance. Moreover, Debye temperature was calculated for both cubic and hexagonal structures of TbO in question by averaging the computed sound velocities. Keywords: DFT, TbO, Elastic properties, Thermodynamic properties
International Nuclear Information System (INIS)
Ionova, G.; Rabbe, C.; Charbonnel, M.C.; Hill, C.; Guillaumont, D.; Guillaumont, R.; Ionov, S.; Madic, C.
2004-01-01
We report here the results obtained from a systematic theoretical study on the thermodynamic properties of trivalent lanthanide (Ln) and actinide (An) complexes with chelating nitrogen tridentate ligands. The mechanism of chelation has been investigated and the role of cation dissolution is investigated through a comparison of the thermodynamic properties of solvated cations and complexes. The difference in thermodynamic properties of LnL and AnL complexes is analyzed. (authors)
Chakraborty, Anutosh
2009-02-17
Thermodynamic property surfaces for a single-component adsorbent + adsorbate system are derived and developed from the viewpoint of classical thermodynamics, thermodynamic requirements of chemical equilibrium, Gibbs law, and Maxwell relations. They enable us to compute the entropy and enthalpy of the adsorbed phase, the isosteric heat of adsorption, specific heat capacity, and the adsorbed phase volume thoroughly. These equations are very simple and easy to handle for calculating the energetic performances of any adsorption system. We have shown here that the derived thermodynamic formulations fill up the information gap with respect to the state of adsorbed phase to dispel the confusion as to what is the actual state of the adsorbed phase. We have also discussed and established the temperature-entropy diagrams of (i) CaCl 2-in-silica gel + water system for cooling applications, and (ii) activated carbon (Maxsorb III) + methane system for gas storage. © Copyright 2009 American Chemical Society.
Thermodynamics for scientists and engineers
International Nuclear Information System (INIS)
Lim, Gyeong Hui
2011-02-01
This book deals with thermodynamics for scientists and engineers. It consists of 11 chapters, which are concept and background of thermodynamics, the first law of thermodynamics, the second law of thermodynamics and entropy, mathematics related thermodynamics, properties of thermodynamics on pure material, equilibrium, stability of thermodynamics, the basic of compound, phase equilibrium of compound, excess gibbs energy model of compound and activity coefficient model and chemical equilibrium. It has four appendixes on properties of pure materials and thermal mass.
Han, Bumsoo; Bischof, John C
2004-04-01
Understanding the phase change behavior of biomaterials during freezing/thawing including their thermal properties at low temperatures is essential to design and improve cryobiology applications such as cryopreservation and cryosurgery. However, knowledge of phase change behavior and thermal properties of various biomaterials is still incomplete, especially at cryogenic temperatures (solutions--either water-NaCl or phosphate buffered saline (PBS)--with various chemical additives were investigated. The chemical additives studied are glycerol and raffinose as CPAs, an AFP (Type III, molecular weight = 6500), and NaCl as a cryosurgical adjuvant. The phase change behavior was investigated using a differential scanning calorimeter (DSC) and a cryomicroscope. The specific and latent heat of these solutions were also measured with the DSC. The saline solutions have two distinct phase changes--water/ice and eutectic phase changes. During freezing, eutectic solidification of both water-NaCl and PBS are significantly supercooled below their thermodynamic equilibrium eutectic temperatures. However, their melting temperatures are close to thermodynamic equilibrium during thawing. These eutectic phase changes disappear when even a small amount (0.1 M glycerol) of CPA was added, but they are still observed after the addition of an AFP. The specific heats of these solutions are close to that of ice at very low temperatures (< or = -100 degrees C) regardless of the additives, but they increase between -100 degrees C and -30 degrees C with the addition of CPAs. The amount of latent heat, which is evaluated with sample weight, generally decreases with the addition of the additives, but can be normalized to approximately 300 J/g based on the weight of water which participates in the phase change. This illustrates that thermal properties, especially latent heat, of a biomaterial should be evaluated based on the understanding of its phase change behavior. The results of the present
The elastic and thermodynamic properties of ZrMo2 from first principles calculations
International Nuclear Information System (INIS)
Liu, Xian-Kun; Zhou, Wei; Zheng, Zhou; Peng, Shu-Ming
2014-01-01
Highlights: • Elastic and thermodynamic properties of ZrMo 2 under high temperature and pressure are calculated by first principles. • Mechanical stability is testified from elastic constants at zero pressure. • Phonon scattering of ZrMo 2 under different temperature are obtained. - Abstract: The elastic and thermodynamic properties of ZrMo 2 under high temperature and pressure are investigated by first-principles calculations based on pseudopotential plane-wave density functional theory (DFT) within the generalized gradient approximation (GGA) and quasi-harmonic Debye model. The calculated lattice parameters are in good agreement with the available experimental data. The calculated elastic constants of ZrMo 2 increase monotonically with increasing pressure, and the relationship between the elastic constants and pressure show that ZrMo 2 satisfies the mechanical stability criteria under applied pressure (0–65 GPa). The related mechanical properties such as bulk modulus (B), shear modulus (G), Young’s modulus (E), and Poisson’s ratio (v) are also studied for polycrystalline of ZrMo 2 . The calculated B/G value shows that ZrMo 2 behaves in a ductile manner, and higher pressure can significantly improve the ductility of ZrMo 2 . The pressure and temperature dependencies of the relative volume, the bulk modulus, the elastic constants, the heat capacity and the thermal expansion coefficient, as well as the Grüneisen parameters are obtained and discussed by the quasi-harmonic Debye model in the ranges of 0–1800 K and 0–65 GPa
Directory of Open Access Journals (Sweden)
Ravikiran Allada
2017-01-01
Full Text Available Aims: Carvedilol phosphate (CDP is a nonselective beta-blocker used for the treatment of heart failures and hypertension. In this work, moisture sorption–desorption characteristics and thermodynamic properties of CDP have been investigated. Materials and Methods: The isotherms were determined using dynamic vapor sorption analyzer at different humidity conditions (0%–90% relative humidity and three pharmaceutically relevant temperatures (20°C, 30°C, and 40°C. The experimental sorption data determined were fitted to various models, namely, Brunauer–Emmett–Teller; Guggenheim-Anderson-De Boer (GAB; Peleg; and modified GAB. Isosteric heats of sorption were evaluated through the direct use of sorption isotherms by means of the Clausius-Clapeyron equation. Statistical Analysis Used: The sorption model parameters were determined from the experimental sorption data using nonlinear regression analysis, and mean relative percentage deviation (P, correlation (Correl, root mean square error, and model efficiency were considered as the criteria to select the best fit model. Results: The sorption–desorption isotherms have sigmoidal shape – confirming to Type II isotherms. Based on the statistical data analysis, modified GAB model was found to be more adequate to explain sorption characteristics of CDP. It is noted that the rate of adsorption and desorption is specific to the temperature at which it was being studied. It is observed that isosteric heat of sorption decreased with increasing equilibrium moisture content. Conclusions: The calculation of the thermodynamic properties was further used to draw an understanding of the properties of water and energy requirements associated with the sorption behavior. The sorption–desorption data and the set of equations are useful in the simulation of processing, handling, and storage of CDP and further behavior during manufacture and storage of CDP formulations.
Electronic, thermodynamics and mechanical properties of LaB6 from first-principles
Ivashchenko, V. I.; Turchi, P. E. A.; Shevchenko, V. I.; Medukh, N. R.; Leszczynski, Jerzy; Gorb, Leonid
2018-02-01
Up to date, the electronic structure properties of amorphous lanthanum hexaboride, a-LaB6, were not yet investigated, and the thermodynamic and mechanical properties of crystalline lanthanum hexaboride (c-LaB6) were studied incompletely. The goal of this work was to fill these gaps in the study of lanthanum hexaborides. The electronic and phonon structures, thermodynamic and mechanical properties of both crystalline and amorphous lanthanum hexaborides (c-LaB6, a-LaB6, respectively) were investigated within the density functional theory. An amorphyzation of c-LaB6 gives rise to the metal - semiconductor transition. The thermal conductivity decreases on going from c-LaB6 to a-LaB6. The elastic moduli, hardness, ideal tensile and shear strengths of a-LaB6 are significantly lower compared to those of the crystalline counterpart, despite the formation of the icosahedron-like boron network in the amorphous phase. For c-LaB6, the stable boron octahedrons are preserved after the failure under tensile and shear strains. The peculiarity in the temperature dependence of heat capacity, Cp(T), at 50 K is explained by the availability of a sharp peak at 100 cm-1 in the phonon density of states of c-LaB6. An analysis of the Fermi surface indicates that this peak is not related to the shape of the Fermi surface, and is caused by the vibration of lanthanum atoms. In the phonon spectrum of a-LaB6, the peak at 100 cm-1 is significantly broader than in the spectrum of c-LaB6, for which reason the anomaly in the Cp(T) dependence of a-LaB6 does not appear. The calculated characteristics are in good agreement with the available experimental data.
International Nuclear Information System (INIS)
Fang Zheng; Qiu Guanzhou
2007-01-01
A metallic solution model with adjustable parameter k has been developed to predict thermodynamic properties of ternary systems from those of its constituent three binaries. In the present model, the excess Gibbs free energy for a ternary mixture is expressed as a weighted probability sum of those of binaries and the k value is determined based on an assumption that the ternary interaction generally strengthens the mixing effects for metallic solutions with weak interaction, making the Gibbs free energy of mixing of the ternary system more negative than that before considering the interaction. This point is never considered in the models currently reported, where the only difference in a geometrical definition of molar values of components is considered that do not involve thermodynamic principles but are completely empirical. The current model describes the results of experiments very well, and by adjusting the k value also agrees with those from models used widely in the literature. Three ternary systems, Mg-Cu-Ni, Zn-In-Cd, and Cd-Bi-Pb are recalculated to demonstrate the method of determining k and the precision of the model. The results of the calculations, especially those in Mg-Cu-Ni system, are better than those predicted by the current models in the literature
Thermodynamics properties of complexation and extraction of LN(3) by diamides
International Nuclear Information System (INIS)
Charbonnel, M.C.; Flandin, J.L.; Presson, M.T.; Morel, J.P.
2000-01-01
In the frame of the French program SPIN, CEA has undertaken the development of the DIAMEX process which is the first step in the strategy of separation of minor actinides from fission products in High Level Waste. The extractant belongs to the diamide family and lead to a co-extraction actinides(III) - lanthanides(III). The study focuses on thermodynamic properties (ΔH, ΔG, ΔS) related to the extraction of lanthanide elements by malonamide in order to have a better knowledge of the driven force and to explain some extraction differences between extractants. The main experimental technique used is the microcalorimetric titration whose principle will be detailed. Preliminary studies concern reactions of complexation Ln 3+ - diamide in an homogeneous aqueous phase. We can assume that reaction is endothermic but some difficulties were encountered to obtain both K and ΔH because of low complexation constants and small heats of reaction. Additional studies were carried out with spectroscopic methods (UV-Visible and LITRFS) to determine precise ΔG r values. The variation in the lanthanide series was also studied. The main work deals with the thermodynamic constants of extraction for which both micro-calorimetry and classical Vant'Hoff approaches were studied: the results will be presented and discussed. (authors)
DEFF Research Database (Denmark)
Kotkowiak, Weronika; Lisowiec-Wachnicka, Jolanta; Grynda, Jakub
2018-01-01
Thrombin is a serine protease that plays a crucial role in hemostasis, fibrinolysis, cell proliferation, and migration. Thrombin binding aptamer (TBA) is able to inhibit the activity of thrombin molecule via binding to its exosite I. This 15-nt DNA oligonucleotide forms an intramolecular, antipar......Thrombin is a serine protease that plays a crucial role in hemostasis, fibrinolysis, cell proliferation, and migration. Thrombin binding aptamer (TBA) is able to inhibit the activity of thrombin molecule via binding to its exosite I. This 15-nt DNA oligonucleotide forms an intramolecular......, antiparallel G-quadruplex structure with a chair-like conformation. In this paper, we report on our investigations on the influence of certain modified nucleotide residues on thermodynamic stability, folding topology, and biological properties of TBA variants. In particular, the effect of single incorporation......-quadruplex thermodynamic and biological stability, and that the effect is strongly position dependent. Interestingly, TBA variants containing the modified nucleotide residues are characterized by unchanged folding topology. Thrombin time assay revealed that incorporation of certain UNA residues may improve G...
International Nuclear Information System (INIS)
Oliveira, Juliana A.S.A.; Monte, Manuel J.S.; Notario, R.; Ribeiro da Silva, Maria D.M.C.
2014-01-01
Highlights: • A thermodynamic study of two fluorene derivatives is presented. • Vapour pressures and energies of combustion were measured. • Enthalpy, entropy and Gibbs energy of sublimation were derived. • Enthalpy and Gibbs energy of formation in crystal and gas phases were calculated. • Gas phase enthalpy of formation was also estimated by quantum chemical calculations. - Abstract: This report presents a comprehensive experimental and computational study of the thermodynamic properties of two fluorene derivatives: 2-aminofluorene and 2-nitrofluorene. The standard (p° = 0.1 MPa) molar enthalpies of formation in the crystalline phase of these compounds were derived from the standard molar energies of combustion, in oxygen, at T = 298.15 K, measured by static bomb combustion calorimetry. A Knudsen effusion method was used to perform the vapour pressure study of the referred compounds, yielding an accurate determination of the standard molar enthalpies and entropies of sublimation. The enthalpies of sublimation were also determined using Calvet microcalorimetry and the enthalpy and temperature of fusion were derived from DSC experiments. Derived results of standard enthalpy and Gibbs energy of formation in both gaseous and crystalline phases were compared with the ones reported in literature for fluorene. A theoretical study at the G3 and G4 levels has been carried out, and the calculated enthalpies of formation have been compared to the experimental values
Thermodynamics properties of complexation and extraction of LN(3) by diamides
Energy Technology Data Exchange (ETDEWEB)
Charbonnel, M.C.; Flandin, J.L.; Presson, M.T. [CEA/VALRHO - site de Marcoule, Dept. de Recherche en Retraitement et en Vitrification, DRRV, 30 - Marcoule (France); Morel, J.P. [Universite Blaise Pascal, Clermont-Ferrand II, Lab. de Chimie Physique des Solutions, (CNRS), 63 - Aubiere (France)
2000-07-01
In the frame of the French program SPIN, CEA has undertaken the development of the DIAMEX process which is the first step in the strategy of separation of minor actinides from fission products in High Level Waste. The extractant belongs to the diamide family and lead to a co-extraction actinides(III) - lanthanides(III). The study focuses on thermodynamic properties ({delta}H, {delta}G, {delta}S) related to the extraction of lanthanide elements by malonamide in order to have a better knowledge of the driven force and to explain some extraction differences between extractants. The main experimental technique used is the microcalorimetric titration whose principle will be detailed. Preliminary studies concern reactions of complexation Ln{sup 3+} - diamide in an homogeneous aqueous phase. We can assume that reaction is endothermic but some difficulties were encountered to obtain both K and {delta}H because of low complexation constants and small heats of reaction. Additional studies were carried out with spectroscopic methods (UV-Visible and LITRFS) to determine precise {delta}G{sub r} values. The variation in the lanthanide series was also studied. The main work deals with the thermodynamic constants of extraction for which both micro-calorimetry and classical Vant'Hoff approaches were studied: the results will be presented and discussed. (authors)
Thermodynamic properties of copper compounds with oxygen and hydrogen from first principles
International Nuclear Information System (INIS)
Korzhavyi, P.A.; Johansson, B.
2010-02-01
We employ quantum-mechanical calculations (based on density functional theory and linear response theory) in order to test the mechanical and chemical stability of several solid-state configurations of Cu 1+ , Cu 2+ , O 2- , H 1- , and H 1+ ions. We begin our analysis with cuprous oxide (Cu 2 O, cuprite structure), cupric oxide (CuO, tenorite structure), and cuprous hydride (CuH, wurtzite and sphalerite structures) whose thermodynamic properties have been studied experimentally. In our calculations, all these compounds are found to be mechanically stable configurations. Their formation energies calculated at T = 0 K (including the energy of zero-point and thermal motion of the ions) and at room temperature are in good agreement with existing thermodynamic data. A search for other possible solid-state conformations of copper, hydrogen, and oxygen ions is then performed. Several candidate structures for solid phases of cuprous oxy-hydride (Cu 4 H 2 O) and cupric hydride (CuH 2 ) have been considered but found to be dynamically unstable. Cuprous oxy-hydride is found to be energetically unstable with respect to decomposition onto cuprous oxide and cuprous hydride. Metastability of cuprous hydroxide (CuOH) is established in our calculations. The free energy of CuOH is calculated to be some 50 kJ/mol higher than the average of the free energies of Cu 2 O and water. Thus, cuprite Cu 2 O is the most stable of the examined Cu(I) compounds
International Nuclear Information System (INIS)
Zhang Xiao-Lin; Wu Yuan-Yuan; Shao Xiao-Hong; Lu Yong; Zhang Ping
2016-01-01
The high pressure behaviors of Th 4 H 15 and ThH 2 are investigated by using the first-principles calculations based on the density functional theory (DFT). From the energy–volume relations, the bct phase of ThH 2 is more stable than the fcc phase at ambient conditions. At high pressure, the bct ThH 2 and bcc Th 4 H 15 phases are more brittle than they are at ambient pressure from the calculated elastic constants and the Poisson ratio. The thermodynamic stability of the bct phase ThH 2 is determined from the calculated phonon dispersion. In the pressure domain of interest, the phonon dispersions of bcc Th 4 H 15 and bct ThH 2 are positive, indicating the dynamical stability of these two phases, while the fcc ThH 2 is unstable. The thermodynamic properties including the lattice vibration energy, entropy, and specific heat are predicted for these stable phases. The vibrational free energy decreases with the increase of the temperature, and the entropy and the heat capacity are proportional to the temperature and inversely proportional to the pressure. As the pressure increases, the resistance to the external pressure is strengthened for Th 4 H 15 and ThH 2 . (paper)
Xiao-Lin, Zhang; Yuan-Yuan, Wu; Xiao-Hong, Shao; Yong, Lu; Ping, Zhang
2016-05-01
The high pressure behaviors of Th4H15 and ThH2 are investigated by using the first-principles calculations based on the density functional theory (DFT). From the energy-volume relations, the bct phase of ThH2 is more stable than the fcc phase at ambient conditions. At high pressure, the bct ThH2 and bcc Th4H15 phases are more brittle than they are at ambient pressure from the calculated elastic constants and the Poisson ratio. The thermodynamic stability of the bct phase ThH2 is determined from the calculated phonon dispersion. In the pressure domain of interest, the phonon dispersions of bcc Th4H15 and bct ThH2 are positive, indicating the dynamical stability of these two phases, while the fcc ThH2 is unstable. The thermodynamic properties including the lattice vibration energy, entropy, and specific heat are predicted for these stable phases. The vibrational free energy decreases with the increase of the temperature, and the entropy and the heat capacity are proportional to the temperature and inversely proportional to the pressure. As the pressure increases, the resistance to the external pressure is strengthened for Th4H15 and ThH2. Project supported by the Long-Term Subsidy Mechanism from the Ministry of Finance and the Ministry of Education of China.
International Nuclear Information System (INIS)
Urrutia, Ignacio
2015-01-01
Recently, new insights into the relation between the geometry of the vessel that confines a fluid and its thermodynamic properties were traced through the study of cluster integrals for inhomogeneous fluids. In this work, I analyze the thermodynamic properties of fluids confined in wedges or by edges, emphasizing on the question of the region to which these properties refer. In this context, the relations between the line-thermodynamic properties referred to different regions are derived as analytic functions of the dihedral angle α, for 0 < α < 2π, which enables a unified approach to both edges and wedges. As a simple application of these results, I analyze the properties of the confined gas in the low-density regime. Finally, using recent analytic results for the second cluster integral of the confined hard sphere fluid, the low density behavior of the line thermodynamic properties is analytically studied up to order two in the density for 0 < α < 2π and by adopting different reference regions
Thermodynamic properties and equation of state of liquid lead and lead bismuth eutectic
Sobolev, V. P.; Schuurmans, P.; Benamati, G.
2008-06-01
Since the 1950s, liquid lead (Pb) and lead-bismuth eutectic (Pb-Bi) have been studied in the USA, Canada and in the former-USSR as potential coolants for nuclear installations due to their very attractive thermophysical and neutronic properties. However, experimental data on the thermal properties of these coolants in the temperature range of interest are still incomplete and often contradictory. This makes it very difficult to perform design calculations and to analyse the normal and abnormal behaviour of nuclear installations where these coolants are expected to be used. Recently, a compilation of heavy liquid metal (HLM) properties along with recommendations for its use was prepared by the OECD/NEA Working Party on Fuel Cycle (WPFC) Expert Group on Lead-Bismuth Eutectic Technology. A brief review of this compilation and some new data are presented in this article. A set of correlations for the temperature dependence of the main thermodynamic properties of Pb and Pb-Bi(e) at normal pressure, and a set of simplified thermal and caloric equations of state for the liquid phase are proposed.
International Nuclear Information System (INIS)
Apelblat, Alexander; Korin, Eli; Manzurola, Emanuel
2013-01-01
Highlights: • Over a wide range of concentrations and temperatures sound velocities were measured in aqueous solutions of citric acid. • Compressibility properties of citric acid solutions are thermodynamically characterized. • Changes in the structure of water when citric acid is dissolved are discussed. -- Abstract: Sound velocities in aqueous solutions of citric acid were measured from 15 °C to 50 °C in 5 °C intervals, within the 0.1 mol · kg −1 to 5.0 mol · kg −1 concentration range. These sound velocities served to evaluate the isentropic and isothermal compressibilities, the apparent molar compressibilities, the isochoric thermal pressure coefficients, changes of the cubic expansion coefficients with pressure at constant temperature, the changes of heat capacities with volume and hydration numbers of citric acid in aqueous solutions
Phonon and thermodynamical properties of CuSc: A DFT study
Jain, Ekta; Pagare, Gitanjali; Dubey, Shubha; Sanyal, S. P.
2018-05-01
A detailed systematic theoretical investigation of phonon and thermodynamical behavior of CuSc intermetallic compound has been carried out by uing first-principles density functional theory in B2-type (CsCl) crystal structure. Phonon dispersion curve and phonon density of states (PhDOS) are studied which confirm the stability of CuSc intermetallic compound in B2 phase. It is found that PhDOS at high frequencies mostly composed of Sc states. We have also presented some temperature dependent properties such as entropy, free energy, heat capacity, internal energy and thermal displacement, which are computed under PHONON code. The various features of these quantities are discussed in detail. From these results we demonstrate that the particular intermetallic have better ductility and larger thermal expansion.
Investigation methods for the determination of thermodynamic properties of lithium alloys
International Nuclear Information System (INIS)
Sommer, F.
1981-01-01
For the determination of thermodynamic properties of the highly reactive lithium alloys, during the last years a number of measuring methods, especially apt for the investigation of these systems, have been developed. The most important measuring arrangements are presented in regard to their manner of function and their technical applicability for the measurements. Among these devices are high temperature calorimeters for the determination of mixing enthalpies of liquid alloys, whilst the formation enthalpies of intermetallic compounds can be determined using a suitable solution calorimeter. Heat contents measurements using a drop calorimeter are resulting in the determination of specific heats, of the enthalpy of fusion and of the temperature dependence of the mixing enthalpy. The Gibbs free enthalpy of mixing of lithium alloys can successfully be determined using suitable galvanic cells. (orig.)
Shi, Kaile; Jiang, Wei; Guo, Anbang; Wang, Kai; Wu, Chuang
2018-06-01
The magnetic and thermodynamic properties of borophene structure have been studied for the first time by Monte Carlo simulation. Two-dimensional borophene structure consisting of seven hexagonal B36 units is described by Ising model. Each B36 basic unit includes three benzene-like with spin-3/2. The general formula for the borophene structure is given. The numerical results of the magnetization, the magnetic susceptibility, the internal energy and the specific heat are studied with various parameters. The possibility to test the predicted magnetism in experiment are illustrated, for instance, the maximum on the magnetization curve. The multiple hysteresis loops and the magnetization plateaus are sensitive to the ferromagnetic or ferrimagnetic exchange coupling in borophene structure. The results show the borophene structure could have applications in spintronics, which deserves further studies in experiments.
Directory of Open Access Journals (Sweden)
A. Zuber
2015-09-01
Full Text Available AbstractThe correlation of thermodynamic properties of nonaqueous electrolyte solutions is relevant to design and operation of many chemical processes, as in fertilizer production and the pharmaceutical industry. In this work, the Q-electrolattice equation of state (EOS is used to model vapor pressure, mean ionic activity coefficient, osmotic coefficient, and liquid density of sixteen methanol and ten ethanol solutions containing single strong 1:1 and 2:1 salts. The Q-electrolattice comprises the lattice-based Mattedi-Tavares-Castier (MTC EOS, the Born term and the explicit MSA term. The model requires two adjustable parameters per ion, namely the ionic diameter and the solvent-ion interaction energy. Predictions of osmotic coefficient at 298.15 K and liquid density at different temperatures are also presented.
Thermodynamic properties of the liquid Bi-Cu-Sn lead-free solder alloys
Directory of Open Access Journals (Sweden)
Kopyto M.
2009-01-01
Full Text Available The electromotive force measurement method was employed to determine the thermodynamic properties of liquid Bi-Cu-Sn alloys using solid electrolyte galvanic cells as shown below: Kanthal+Re, Bi-Cu-Sn, SnO2 | Yttria Stabilized Zirconia | air, Pt, Po2=0.2:1 atm Measurements were carried out for three cross-sections with constant Bi/Cu ratio equal to: 1/3, 1 and 3 and for various tin content varying every 10%, resulting in a total of 26 different alloy compositions. The temperature of the measurements varied within the range from 973 to 1325 K. A linear dependence of the e.m.f. on temperature was observed for all alloy compositions and the appropriate line equations were derived. Tin activities were calculated as function of composition and temperature. Results were presented in tables and figures.
Ab initio calculation of the thermodynamic properties of InSb under intense laser irradiation
International Nuclear Information System (INIS)
Feng, ShiQuan; Cheng, XinLu; Zhao, JianLing; Zhang, Hong
2013-01-01
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 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
Ab initio calculation of the thermodynamic properties of InSb under intense laser irradiation
Feng, ShiQuan; Zhao, JianLing; Cheng, XinLu; Zhang, Hong
2013-07-01
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 Te = 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.
Thermodynamic properties of isomeric iso-butoxybenzoic acids: Experimental and theoretical study
International Nuclear Information System (INIS)
Jakubczyk, Michał; Sporzyński, Andrzej; Emel’yanenko, Vladimir N.; Varfolomeev, Mikhail A.; Verevkin, Sergey P.
2015-01-01
Highlights: • Vapor pressures of butoxy benzoic acid derivatives were measured. • Vaporization, sublimation and fusion enthalpies were derived. • Molar enthalpies of formation were measured by calorimetry. • Thermochemical data tested for consistency using additivity rules and computations. • Simple additivity method suggested for prediction thermochemical properties. - Abstract: Standard (p° = 0.1 MPa) molar enthalpies of formation at the temperature T = 298.15 K of the 2-, 3-, and 4-iso-butoxybenzoic acids were measured using the combustion calorimetry. Standard molar enthalpies of vaporization and sublimation were derived from the vapor pressure temperature dependencies measured by the transpiration method. Molar enthalpies of the solid state phase transitions were measured by the DSC. Thermodynamic data on alkoxy substituted benzoic acids available in the literature were collected and combined with own experimental results. This data set on alkoxybenzoic acids was evaluated by using quantum-chemical and group-additivity methods
International Nuclear Information System (INIS)
Fortin, Xavier
1971-01-01
The effects of thermal excitation are introduced in the study of a simple electronic structure model for condensed media. The choice of a particle-interaction potential leads to a self-consistent calculation performed on a computer. This calculation gives a metal - nonmetal transition similar to the MOTT transition. We consider the effects of temperature and density variations upon this transition. It is possible to make use of this electronic structure to obtain the thermodynamic properties near the transition: pressure, free energy, sound velocity. The numerical results of this simple model are satisfactory. Particularly, if a dielectric constant is taken into account, the transition temperature and density are of the same order of magnitude as those observed experimentally in semiconductors. (author) [fr
Study of thermodynamic water properties and moisture sorption hysteresis of mango skin
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Silvio José Ferreira de Souza
2015-03-01
Full Text Available The equilibrium moisture content for adsorption and desorption isotherms of mango skin was determined using the static gravimetric method at temperatures of 20, 26, 33, 38 and 44 oC in the 0.056 to 0.873 water activity range. Both sorption curves show a decrease in equilibrium moisture content as the temperature increasing. The hysteresis effect was observed at constant water activity. The Guggenheim, Anderson, and de Boer (GAB model presented the best fitting accuracy among a group of models and was used to determine the thermodynamic properties of water sorption. Integral enthalpy and integral entropy areas showed inverted values for the adsorption and desorption isotherms over the wide range of water activity studied. These values confirm, in energetic terms, the difference between adsorption and desorption isotherms observed in the hysteresis phenomenon. Finally, the Gibbs free energy revealed that the sorption process was spontaneous for both sorption isotherms.
Ab initio thermodynamic properties of stoichiometric phases in the Ni-Al system
International Nuclear Information System (INIS)
Arroyave, R.; Shin, D.; Liu, Z.-K.
2005-01-01
In this work the thermodynamic properties of Al, Ni, NiAl and Ni 3 Al were obtained through ab initio methods. Through the use of density functional theory within the generalized gradient approximation and projector augmented-wave (PAW) pseudopotentials, the 0 K energetics of the structures were calculated. The supercell method was used to calculate the vibrational contributions to the free energy. The contribution of electronic degrees of freedom to the total free energy was also included in the calculations. The resulting free energy was used to calculate the enthalpies and entropies of the structures investigated. The comparison with experimental data is satisfactory, and the calculations compare well with recent results using linear response theory
Equation of state for thermodynamic properties of pure and mixtures liquid alkali metals
International Nuclear Information System (INIS)
Mousazadeh, M.H.; Faramarzi, E.; Maleki, Z.
2010-01-01
We developed an equation of state based on statistical-mechanical perturbation theory for pure and mixtures alkali metals. Thermodynamic properties were calculated by the equation of state, based on the perturbed-chain statistical associating fluid theory (PC-SAFT). The model uses two parameters for a monatomic system, segment size, σ, and segment energy, ε. In this work, we calculate the saturation and compressed liquid density, heat capacity at constant pressure and constant volume, isobaric expansion coefficient, for which accurate experimental data exist in the literatures. Results on the density of binary and ternary alkali metal alloys of Cs-K, Na-K, Na-K-Cs, at temperatures from the freezing point up to several hundred degrees above the boiling point are presented. The calculated results are in good agreement with experimental data.
Thermodynamic properties of isomeric iso-butoxybenzoic acids: Experimental and theoretical study
Energy Technology Data Exchange (ETDEWEB)
Jakubczyk, Michał; Sporzyński, Andrzej [Faculty of Chemistry, Warsaw University of Technology, 00-664 Warszawa (Poland); Emel’yanenko, Vladimir N.; Varfolomeev, Mikhail A. [Department of Physical Chemistry, Kazan Federal University, 420008 Kazan (Russian Federation); Verevkin, Sergey P., E-mail: sergey.verevkin@uni-rostock.de [Department of Physical Chemistry, Kazan Federal University, 420008 Kazan (Russian Federation); Department of Physical Chemistry and Department, Science and Technology of Life, Light and Matter, University of Rostock, D-18059 Rostock (Germany)
2015-09-10
Highlights: • Vapor pressures of butoxy benzoic acid derivatives were measured. • Vaporization, sublimation and fusion enthalpies were derived. • Molar enthalpies of formation were measured by calorimetry. • Thermochemical data tested for consistency using additivity rules and computations. • Simple additivity method suggested for prediction thermochemical properties. - Abstract: Standard (p° = 0.1 MPa) molar enthalpies of formation at the temperature T = 298.15 K of the 2-, 3-, and 4-iso-butoxybenzoic acids were measured using the combustion calorimetry. Standard molar enthalpies of vaporization and sublimation were derived from the vapor pressure temperature dependencies measured by the transpiration method. Molar enthalpies of the solid state phase transitions were measured by the DSC. Thermodynamic data on alkoxy substituted benzoic acids available in the literature were collected and combined with own experimental results. This data set on alkoxybenzoic acids was evaluated by using quantum-chemical and group-additivity methods.
Thermodynamic properties of the S =1 /2 twisted triangular spin tube
Ito, Takuya; Iino, Chihiro; Shibata, Naokazu
2018-05-01
Thermodynamic properties of the twisted three-leg spin tube under magnetic field are studied by the finite-T density-matrix renormalization group method. The specific heat, spin, and chiral susceptibilities of the infinite system are calculated for both the original and its low-energy effective models. The obtained results show that the presence of the chirality is observed as a clear peak in the specific heat at low temperature and the contribution of the chirality dominates the low-temperature part of the specific heat as the exchange coupling along the spin tube decreases. The peak structures in the specific heat, spin, and chiral susceptibilities are strongly modified near the quantum phase transition where the critical behaviors of the spin and chirality correlations change. These results confirm that the chirality plays a major role in characteristic low-energy behaviors of the frustrated spin systems.
Energy Technology Data Exchange (ETDEWEB)
Zhang, Huai-Yong; Zhao, Ying-Qin; Lu, Qing [Sichuan Univ., Chengdu (China). Inst. of Atomic and Molecular Physics; Zeng, Zhao-Yi [Chongqing Normal Univ. (China). College of Physics and Electronic Engineering; Chinese Academy of Engineering Physics, Mianyang (China). National Key Laboratory for Shock Wave and Detonation Physics Research; Cheng, Yan [Sichuan Univ., Chengdu (China). Inst. of Atomic and Molecular Physics; Sichuan Univ., Chengdu (China). Key Laboratory of High Energy Density Physics and Technology of Ministry of Education
2016-11-01
Lattice dynamics, structural phase transition, and the thermodynamic properties of barium titanate (BaTiO{sub 3}) are investigated by using first-principles calculations within the density functional theory (DFT). It is found that the GGA-WC exchange-correlation functional can produce better results. The imaginary frequencies that indicate structural instability are observed for the cubic, tetragonal, and orthorhombic phases of BaTiO{sub 3} and no imaginary frequencies emerge in the rhombohedral phase. By examining the partial phonon density of states (PDOSs), we find that the main contribution to the imaginary frequencies is the distortions of the perovskite cage (Ti-O). On the basis of the site-symmetry consideration and group theory, we give the comparative phonon symmetry analysis in four phases, which is useful to analyze the role of different atomic displacements in the vibrational modes of different symmetry. The calculated optical phonon frequencies at Γ point for the four phases are in good agreement with other theoretical and experimental data. The pressure-induced phase transition of BaTiO{sub 3} among four phases and the thermodynamic properties of BaTiO{sub 3} in rhombohedral phase have been investigated within the quasi-harmonic approximation (QHA). The sequence of the pressure-induced phase transition is rhombohedral → orthorhombic → tetragonal → cubic, and the corresponding transition pressure is 5.17, 5.92, 6.65 GPa, respectively. At zero pressure, the thermal expansion coefficient α{sub V}, heat capacity C{sub V}, Grueneisen parameter γ, and bulk modulus B of the rhombohedral phase BaTiO{sub 3} are estimated from 0 K to 200 K.
International Nuclear Information System (INIS)
Soezen, Adnan; Arcaklioglu, Erol; Oezalp, Mehmet
2005-01-01
This paper presents a new approach based on artificial neural networks (ANNs) to determine the properties of liquid and two phase boiling and condensing of two alternative refrigerant/absorbent couples (methanol/LiBr and methanol/LiCl). These couples do not cause ozone depletion and use in the absorption thermal systems (ATSs). ANNs are able to learn the key information patterns within multidimensional information domain. ANNs operate such as a 'black box' model, requiring no detailed information about the system. On the other hand, they learn the relationship between the input and the output. In order to train the neural network, limited experimental measurements were used as training data and test data. In this study, in input layer, there are temperatures in the range of 298-498 K, pressures (0.1-40 MPa) and concentrations of 2%, 7%, 12% of the couples; specific volume is in output layer. The back-propagation learning algorithm with three different variants, namely scaled conjugate gradient (SCG), Pola-Ribiere conjugate gradient (CGP), and Levenberg-Marquardt (LM), and logistic sigmoid transfer function were used in the network so that the best approach can find. The most suitable algorithm and neuron number in the hidden layer are found as SCG with 8 neurons. For this number level, after the training, it is found that maximum error is less than 3%, average error is about 1% and R 2 value are 99.999%. As seen from the results obtained the thermodynamic equations for each pair by using the weights of network have been obviously predicted within acceptable errors. This paper shows that values predicted with ANN can be used to define the thermodynamic properties instead of approximate and complex analytic equations
Directory of Open Access Journals (Sweden)
Samujlov E.
2013-04-01
Full Text Available In case of system with chemical reaction the most important properties are heat conductivity and heat capacity. In this work we have considered the equation for estimate the component of these properties caused by chemical reaction and ionization processes. We have evaluated the contribution of this part in heat conductivity and heat capacity too. At the high temperatures contribution in heat conductivity from ionization begins to play an important role. We have created a model, which describe partial and full ionization of gases and gas mixtures. In addition, in this work we present the comparison of our result with experimental data and data from numerical simulation. We was used the data about transport properties of middle composition of Russian coals and the data of thermophysical properties of natural gas for comparison.
International Nuclear Information System (INIS)
Ackermann, R.J.; Chandrasekharaiah, M.S.
1975-01-01
The thermodynamic data for the actinide metals and oxides (thorium to curium ) have been assessed, examined for consistency, and compared with the lanthanides. Correlations relating the enthalpies of formation of the solid oxides with the corresponding aquo ions make possible the estimation of the thermodynamic properties of AmO 2 (s) and Am 2 O 3 (s) which are in accordance with vaporization data. The known thermodynamic properties of the substoichiometric dioxides MOsub(2-x)(s) at high temperatures demonstrate the relative stabilities of valence states less than 4+ and lead to the examination of stability requirements for the sesquioxides M 2 O 3 (s) and the monoxides MO(s). Sequential trends in the gaseous metals, monoxides and dioxides are examined, compared, and contrasted with the lanthanides. (author)
Macroscopic magnetic Self assembly
Löthman, Per Arvid
2018-01-01
Exploring the macroscopic scale's similarities to the microscale is part and parcel of this thesis as reflected in the research question: what can we learn about the microscopic scale by studying the macroscale? Investigations of the environment in which the self-assembly takes place, and the
Directory of Open Access Journals (Sweden)
Nilgün Şen
2016-10-01
Full Text Available The B3LYP/6-311++G(2df,2p density functional theory (DFT method was used to investigate molecular geometry and thermodynamic properties of RDX and RDX derivatives containing Al and B metals. The detonation velocity (D and detonation pressure (P, estimated by using Kamlet–Jacobs and in literature equations, respectively. Total energies (Et, frontier orbital energy (EHOMO, ELOMO, energy gap (ΔELUMO–HOMO and theoretical molecular density (ρ were calculated with Spartan 14 software package program. It was shown that the presence of aluminum and boron atoms affects the good thermal stabilities. The results show that the composite RDX-Al, RDX-B derivatives have higher detonation performance and higher density than RDX. RDX-Al derivatives appeared to be superior to RDX-B mixtures in terms of these parameters. These results provide information on the moleculer design of new energetic materials.
Mesoscopic modeling of structural and thermodynamic properties of fluids confined by rough surfaces.
Terrón-Mejía, Ketzasmin A; López-Rendón, Roberto; Gama Goicochea, Armando
2015-10-21
The interfacial and structural properties of fluids confined by surfaces of different geometries are studied at the mesoscopic scale using dissipative particle dynamics simulations in the grand canonical ensemble. The structure of the surfaces is modeled by a simple function, which allows us to simulate readily different types of surfaces through the choice of three parameters only. The fluids we have modeled are confined either by two smooth surfaces or by symmetrically and asymmetrically structured walls. We calculate structural and thermodynamic properties such as the density, temperature and pressure profiles, as well as the interfacial tension profiles for each case and find that a structural order-disorder phase transition occurs as the degree of surface roughness increases. However, the magnitude of the interfacial tension is insensitive to the structuring of the surfaces and depends solely on the magnitude of the solid-fluid interaction. These results are important for modern nanotechnology applications, such as in the enhanced recovery of oil, and in the design of porous materials with specifically tailored properties.
Theoretical study of elastic, mechanical and thermodynamic properties of MgRh intermetallic compound
Directory of Open Access Journals (Sweden)
S. Boucetta
2014-03-01
Full Text Available In the last years, Magnesium alloys are known to be of great technological importance and high scientific interest. In this work, density functional theory plane-wave pseudo potential method, with local density approximation (LDA and generalized gradient approximation (GGA are used to perform first-principles quantum mechanics calculations in order to investigate the structural, elastic and mechanical properties of the intermetallic compound MgRh with a CsCl-type structure. Comparison of the calculated equilibrium lattice constant and experimental data shows good agreement. The elastic constants were determined from a linear fit of the calculated stress–strain function according to Hooke's law. From the elastic constants, the bulk modulus B, shear modulus G, Young's modulus E, Poisson's ratio σ, anisotropy factor A and the ratio B/G for MgRh compound are obtained. The sound velocities and Debye temperature are also predicted from elastic constants. Finally, the linear response method has been used to calculate the thermodynamic properties. The temperature dependence of the enthalpy H, free energy F, entropy S, and heat capacity at constant volume Cv of MgRh crystal in a quasi-harmonic approximation have been obtained from phonon density of states and discussed for the first report. This is the first quantitative theoretical prediction of these properties.
Hou, Ling; Li, Wei-Dong; Wang, Fangwei; Eriksson, Olle; Wang, Bao-Tian
2017-12-01
We present a systematic investigation of the structural, magnetic, electronic, mechanical, and thermodynamic properties of CmO2 with the local density approximation (LDA)+U and the generalized gradient approximation (GGA)+U approaches. The strong Coulomb repulsion and the spin-orbit coupling (SOC) effects on the lattice structures, electronic density of states, and band gaps are carefully studied, and compared with other A O2 (A =U , Np, Pu, and Am). The ferromagnetic configuration with half-metallic character is predicted to be energetically stable while a charge-transfer semiconductor is predicted for the antiferromagnetic configuration. The elastic constants and phonon spectra show that the fluorite structure is mechanically and dynamically stable. Based on the first-principles phonon density of states, the lattice vibrational energy is calculated using the quasiharmonic approximation. Then, the Gibbs free energy, thermal expansion coefficient, specific heat, and entropy are obtained and compared with experimental data. The mode Grüneisen parameters are presented to analyze the anharmonic properties. The Slack relation is applied to obtain the lattice thermal conductivity in temperature range of 300-1600 K. The phonon group velocities are also calculated to investigate the heat transfer. For all these properties, if available, we compare the results of CmO2 with other A O2 .
Advanced working fluids: Thermodynamic properties. Final report, 1 December 1987-30 November 1989
Energy Technology Data Exchange (ETDEWEB)
Lee, L.L.; Gering, K.L.
1990-09-01
Electrolytes are used as working fluids in gas-fired heat pump-chiller engine cycles. To find out which molecular parameters of the electrolytes impact on cycle performance, a molecular theory, the EXP-MSA correlation, is developed for calculating solution properties, enthalpies, vapor-liquid equilibria, and engine cycle performance. Aqueous and ammoniac single and mixed salt solutions in single and multisolvent systems are investigated. The outcomes are: (1) an accurate correlation is developed to evaluate properties for concentrated electrolyte solutions (e.g., for aqueous LiBr to 19 molal); (2) sensitivity analysis is used to determine the impact of molecular parameters on the thermodynamic properties and cycle performance. The preferred electrolytes are of 1-1 valence type, small ion size, high molecular weight, and in a strongly colligative cosolvent; (3) the abilities of correlation on single-effect and double-effect engine cycles are demonstrated; (4) the operating windows are determined for a number of absorption fluids of industrial importance.
Marcondes, Michel L.; Wentzcovitch, Renata M.; Assali, Lucy V. C.
2018-05-01
Thermal equations of state (EOS) are essential in several scientific domains. However, experimental determination of EOS parameters may be limited at extreme conditions, therefore, ab initio calculations have become an important method to obtain them. Density functional theory (DFT) and its extensions with various degrees of approximations for the exchange and correlation (XC) energy is the method of choice, but large errors in the EOS parameters are still common. The alkali halides have been problematic from the onset of this field and the quest for appropriate DFT functionals for such ionic and relatively weakly bonded systems has remained an active topic of research. Here we use DFT + van der Waals functionals to calculate vibrational properties, thermal EOS, thermodynamic properties, and the B1 to B2 phase boundary of NaCl with high precision. Our results reveal a remarkable improvement over the performance of standard local density approximation and generalized gradient approximation functionals for all these properties and phase transition boundary, as well as great sensitivity of anharmonic effects on the choice of XC functional.
Isentropic expansion and related thermodynamic properties of non-ionic amphiphile-water mixtures.
Reis, João Carlos R; Douhéret, Gérard; Davis, Michael I; Fjellanger, Inger Johanne; Høiland, Harald
2008-01-28
A concise thermodynamic formalism is developed for the molar isentropic thermal expansion, ES,m = ( partial differential Vm/ partial differential T)(Sm,x), and the ideal and excess quantities for the molar, apparent molar and partial molar isentropic expansions of binary liquid mixtures. Ultrasound speeds were determined by means of the pulse-echo-overlap method in aqueous mixtures of 2-methylpropan-2-ol at 298.15 K over the entire composition range. These data complement selected extensive literature data on density, isobaric heat capacity and ultrasound speed for 9 amphiphile (methanol, ethanol, propan-1-ol, propan-2-ol, 2-methylpropan-2-ol, ethane-1,2-diol, 2-methoxyethanol, 2-ethoxyethanol or 2-butoxyethanol)-water binary systems, which form the basis of tables listing molar and excess molar isobaric expansions and heat capacities, and molar and excess molar isentropic compressions and expansions at 298.15 K and at 65 fixed mole fractions spanning the entire composition range and fine-grained in the water-rich region. The dependence on composition of these 9 systems is graphically depicted for the excess molar isobaric and isentropic expansions and for the excess partial molar isobaric and isentropic expansions of the amphiphile. The analysis shows that isentropic thermal expansion properties give a much stronger response to amphiphile-water molecular interactions than do their isobaric counterparts. Depending on the pair property-system, the maximum excess molar isentropic value is generally twenty- to a hundred-fold greater than the corresponding maximum isobaric value, and occurs at a lower mole fraction of the amphiphile. Values at infinite dilution of the 9 amphiphiles in water are given for the excess partial molar isobaric heat capacity, isentropic compression, isobaric expansion and isentropic expansion. These values are interpreted in terms of the changes occurring when amphiphile molecules cluster into an oligomeric form. Present results are discussed
Directory of Open Access Journals (Sweden)
Yuriy Puzachenko
2013-09-01
Full Text Available The paper discusses methods of evaluating thermodynamic properties of landscape cover based on multi-spectral measurements by the Landsat satellites. Authors demonstrate how these methods could be used for studying functionality of landscapes and for spatial interpolation of Flux NET system measurements.
Fang, Bin; Ning, Fulong; Cao, Pinqiang; Peng, Li; Wu, Jianyang; Zhang, Zhun; Vlugt, T.J.H.; Kjelstrup, Signe
2017-01-01
A sound knowledge of thermodynamic properties of sII hydrates is of great importance to understand the stability of sII gas hydrates in petroleum pipelines and in natural settings. Here, we report direct molecular dynamics (MD) simulations of the thermal expansion coefficient, the
DEFF Research Database (Denmark)
Bork, Nicolai Christian; Bonanos, Nikolaos; Rossmeisl, Jan
2011-01-01
A density functional theory investigation of the thermodynamic and kinetic properties of hydrogen–hydrogen defect interactions in the cubic SrTiO3 perovskite is presented. We find a net attraction between two hydrogen atoms with an optimal separation of ∼2.3 Å. The energy gain is ca. 0.33 eV comp...
ShunLi Shang; Louis G. Hector Jr.; Paul Saxe; Zi-Kui Liu; Robert J. Moon; Pablo D. Zavattieri
2014-01-01
Anisotropy and temperature dependence of structural, thermodynamic and elastic properties of crystalline cellulose Iβ 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...
Energy Technology Data Exchange (ETDEWEB)
Konings, Rudy J. M., E-mail: rudy.konings@ec.europa.eu; Beneš, Ondrej; Kovács, Attila; Manara, Dario; Sedmidubský, David [European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, 76125 Karlsruhe (Germany); Gorokhov, Lev; Iorish, Vladimir S.; Yungman, Vladimir; Shenyavskaya, E.; Osina, E. [Joint Institute for High Temperatures, Russian Academy of Sciences, 13-2 Izhorskaya Street, Moscow 125412 (Russian Federation)
2014-03-15
A comprehensive review of the thermodynamic properties of the oxide compounds of the lanthanide and actinide elements is presented. The available literature data for the solid, liquid, and gaseous state have been analysed and recommended values are presented. In case experimental data are missing, estimates have been made based on the trends in the two series, which are extensively discussed.
Bridging scales with thermodynamics: from nano to macro
International Nuclear Information System (INIS)
Kjelstrup, Signe; Bedeaux, Dick; Trinh, Thuat; Schnell, Sondre K; Vlugt, Thijs J H; Simon, Jean-Marc; Bardow, Andre
2014-01-01
We have recently developed a method to calculate thermodynamic properties of macroscopic systems by extrapolating properties of systems of molecular dimensions. Appropriate scaling laws for small systems were derived using the method for small systems thermodynamics of Hill, considering surface and nook energies in small systems of varying sizes. Given certain conditions, Hill's method provides the same systematic basis for small systems as conventional thermodynamics does for large systems. We show how the method can be used to compute thermodynamic data for the macroscopic limit from knowledge of fluctuations in the small system. The rapid and precise method offers an alternative to current more difficult computations of thermodynamic factors from Kirkwood–Buff integrals. When multiplied with computed Maxwell–Stefan diffusivities, agreement is found between computed predictions and experiments of the Fick diffusion coefficients for several binary systems. Diffusion coefficients were obtained by linking the Green–Kubo formulae to the Onsager coefficients. The formulae were used to improve/disprove empirical formulae for diffusion coefficients. (review)
International Nuclear Information System (INIS)
Gailhanou, H.; Gaboreau, S.; Gaucher, E.C.; Blanc, P.; Rogez, J.; Olives, J.; Amouric, M.; Van Miltenburg, J.C.; Michau, N.; Giffaut, E.
2010-01-01
Document available in extended abstract form only. In the context of nuclear waste repositories in argillaceous formations, it is necessary to assess the geochemical behaviour of natural and engineered clay barriers, namely by the stability of clay minerals over long periods of time. However, thermodynamic data of clay minerals, which are required for geochemical modelling, are still poorly known. The present study aims to improve our comprehension of clay mineral stability. The thermodynamic properties of smectite MX-80 and illite IMt-2 (Silver Hill, Montana) have already been determined using calorimetric methods between 0 K and 520 K, under both dried and hydrated states in the case of smectite. In parallel, solubility experiments were carried out in order to determine the solubility products of the clay minerals. Such experiments require some particular precautions as published by May et al. (1986) and Aja and Rosenberg (1992). According to these authors, it is namely important to reach the equilibrium from both under and over saturation and to characterize from a mineralogical point of view the end products. Taking advantage of previous calorimetric measurements, we propose to compare the solubility products obtained here from dissolution experiments with respect to calorimetry results, in order to assess the equilibrium achievement for the solubility experiments. The study is integrated in the Thermochimie project, which aims to provide a consistent thermodynamic database (Thermochimie) for modelling purposes. This work dealing with a smectite and an illite is being completed by the study of a set of typical clays, selected to be well-representative of the clay group. Enthalpies of formation of the minerals were determined by isothermal dissolution calorimetry at 25 deg. C, using a HF-HNO 3 solution. They were obtained by measuring the enthalpies of dissolution of (i) the sample (clay mineral + impurities) and (ii) the oxide or hydroxide constituent mixture
Thermodynamic properties of compounds of Na2O with the oxides of chromium, nickel, and iron
International Nuclear Information System (INIS)
Shaiu, B.J.
1976-10-01
Results of emf measurements on Na 2 O solid electrolytes in binary compounds with Cr 2 O 3 , FeO, and NiO are presented along with thermodynamic properties of these compounds. It was found that reliable thermodynamic data for compounds of NaCrO 2 , Na 2 FeO 2 , NaFeO 2 , Na 2 NiO 2 , and NaNiO 2 at 500 to 800 0 can be obtained by using emf measurements with solid electrolyte cells. The pretreatment of heating the cells in a vacuum of 10 -2 torr at 500 0 C or above for about 12 hours causes the emf dependence on temperature to be very small. The measurements were carried out over the temperature range in which no phase transformations occurred, the ΔC/sub p/ for the compounds involved was reasonably considered as approximately zero. Linear emf-temperature plots were therefore expected for these cells and the equation of ΔG 0 /sub f/ was indeed valid for constant values of ΔH 0 /sub f/ and ΔS 0 /sub f/. The formation of compound NaCrO 2 is thermodynamically favorable in a sodium loop made of austenic stainless steels. The critical oxygen concentration for the formation of NaCrO 2 shows that it is stable in liquid sodium in temperature range from 400 to 1100 0 C and Cr 2 O 3 does not exist with the double oxide in liquid sodium. The existence temperature for (Na 2 O) 2 .FeO in equilibrium with oxygen saturated liquid sodium is 693 0 K or above, for Na 2 FeO 2 it is 1141 0 K or above and for NaFeO 2 it is greater than or equal to 1173 0 K. The double oxides of nickel with sodium oxide are much less stable than the iron double oxides and do therefore not exist in liquid sodium. The nickel in austenitic stainless steel shows the least attack by oxygen saturated liquid sodium
Thermodynamic properties of copper compounds with oxygen and hydrogen from first principles
Energy Technology Data Exchange (ETDEWEB)
Korzhavyi, P.A.; Johansson, B. (Applied Materials Physics, Dept. of Materials Science and Engineering, Royal Inst. of Technology, Stockholm (Sweden))
2010-02-15
We employ quantum-mechanical calculations (based on density functional theory and linear response theory) in order to test the mechanical and chemical stability of several solid-state configurations of Cu1+, Cu2+, O2-, H1-, and H1+ ions. We begin our analysis with cuprous oxide (Cu{sub 2}O, cuprite structure), cupric oxide (CuO, tenorite structure), and cuprous hydride (CuH, wurtzite and sphalerite structures) whose thermodynamic properties have been studied experimentally. In our calculations, all these compounds are found to be mechanically stable configurations. Their formation energies calculated at T = 0 K (including the energy of zero-point and thermal motion of the ions) and at room temperature are in good agreement with existing thermodynamic data. A search for other possible solid-state conformations of copper, hydrogen, and oxygen ions is then performed. Several candidate structures for solid phases of cuprous oxy-hydride (Cu{sub 4}H{sub 2}O) and cupric hydride (CuH{sub 2}) have been considered but found to be dynamically unstable. Cuprous oxy-hydride is found to be energetically unstable with respect to decomposition onto cuprous oxide and cuprous hydride. Metastability of cuprous hydroxide (CuOH) is established in our calculations. The free energy of CuOH is calculated to be some 50 kJ/mol higher than the average of the free energies of Cu{sub 2}O and water. Thus, cuprite Cu{sub 2}O is the most stable of the examined Cu(I) compounds
Macroscopic Optomechanically Induced Transparency
Pate, Jacob; Castelli, Alessandro; Martinez, Luis; Thompson, Johnathon; Chiao, Ray; Sharping, Jay
Optomechanically induced transparency (OMIT) is an effect wherein the spectrum of a cavity resonance is modified through interference between coupled excitation pathways. In this work we investigate a macroscopic, 3D microwave, superconducting radio frequency (SRF) cavity incorporating a niobium-coated, silicon-nitride membrane as the flexible boundary. The boundary supports acoustic vibrational resonances, which lead to coupling with the microwave resonances of the SRF cavity. The theoretical development and physical understanding of OMIT for our macroscopic SRF cavity is the same as that for other recently-reported OMIT systems despite vastly different optomechanical coupling factors and device sizes. Our mechanical oscillator has a coupling factor of g0 = 2 π . 1 ×10-5 Hz and is roughly 38 mm in diameter. The Q = 5 ×107 for the SRF cavity allows probing of optomechanical effects in the resolved sideband regime.
DEFF Research Database (Denmark)
Dyekjær, Jane Dannow; Jonsdottir, Svava Osk
2003-01-01
Quantitative Structure-Property Relationship (QSPR) models for prediction of various thermodynamic properties of simple organic compounds have been developed. A number of new descriptors are proposed and used alongside with descriptors available within the Codessa program. An important feature...... for alkanes, alcohols, diols, ethers, and oxyalcohols, including cyclic alkanes and alcohols. Several good models, having good predictability, have been developed. To enhance the applicability of the QSPR models, simpler expressions for each descriptor have also been developed. This allows for the prediction...
Directory of Open Access Journals (Sweden)
Troter Dragan Z.
2017-01-01
Full Text Available This paper reports the physicochemical (density, dynamic viscosity, electrical conductivity and refractive index and the thermodynamic (thermal expansion coefficient, molecular volume, lattice energy and heat capacity properties of several choline chloride (ChCl based deep eutectic solvents (DESs, with 1:2 mole ratio, respectively: ChCl:propylene glycol, ChCl:1,3-dimethylurea and ChCl:thiourea, at atmospheric pressure as a function of temperature over the range of 293.15–363.15 K. Their properties were also compared with those of some already characterized ChCl-based DESs, namely ChCl:ethylene glycol, ChCl:glycerol and ChCl:urea (1:2 mole ratio. Density, viscosity and refractive index of all DESs decrease with the increasing temperature while the electrical conductivity increases. Viscosity and conductivity of the tested DESs were fitted by both Arrhenius-type and Vogel–Tamman–Fulcher equations. The changes of molar enthalpy, entropy and Gibbs energy of activation, determined using the Eyring theory, demonstrated the interactional factor as predominant over the structural factor for all DES systems. The fractional Walden rule, used to correlate molar conductivity and viscosity, showed an excellent linear behaviour. It was shown that ChCl:propylene glycol DES had properties similar to ChCl:ethylene glycol and ChCl:glycerol DESs. However, the properties (density, viscosity and electrical conductivity of ChCl:1,3-dimethylurea and ChCl: :thiourea DESs were inferior to those of the ChCl:urea DES. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III 45001
Atomistic simulations of thermodynamic properties of Xe gas bubbles in U10Mo fuels
Energy Technology Data Exchange (ETDEWEB)
Hu, Shenyang, E-mail: shenyang.hu@pnnl.gov; Setyawan, Wahyu; Joshi, Vineet V.; Lavender, Curt A.
2017-07-15
Xe gas bubble superlattice formation is observed in irradiated uranium–10 wt% molybdenum (U10Mo) fuels. However, the thermodynamic properties of the bubbles (the relationship among bubble size, equilibrium Xe concentration, and bubble pressure) and the mechanisms of bubble superlattice formation are not well known. In this work, the molecular dynamics (MD) method is used to study these properties and mechanisms. The results provide important inputs for quantitative mesoscale models of gas bubble evolution and fuel performance. In the MD simulations, the embedded-atom method (EAM) potential of U10Mo-Xe [1] is employed. Initial gas bubbles with a low Xe concentration (underpressured) are generated in a body-centered cubic (bcc) U10Mo single crystal. Then Xe atoms are sequentially added into the bubbles one by one, and the evolution of pressure and dislocation emission around the bubbles is analyzed. The relationship between pressure, equilibrium Xe concentration, and radius of the bubbles is established. It was found that an overpressured gas bubble emits partial dislocations with a Burgers vector along the <111> direction and a slip plane of (11-2). Meanwhile, dislocation loop punch out was not observed. The overpressured bubble also induces an anisotropic stress field. A tensile stress was found along <110> directions around the bubble, favoring the nucleation and formation of a face-centered cubic bubble superlattice in bcc U10Mo fuels.
Cluster approach to the prediction of thermodynamic and transport properties of ionic liquids
Seeger, Zoe L.; Kobayashi, Rika; Izgorodina, Ekaterina I.
2018-05-01
The prediction of physicochemical properties of ionic liquids such as conductivity and melting point would substantially aid the targeted design of ionic liquids for specific applications ranging from solvents for extraction of valuable chemicals to biowaste to electrolytes in alternative energy devices. The previously published study connecting the interaction energies of single ion pairs (1 IP) of ionic liquids to their thermodynamic and transport properties has been extended to larger systems consisting of two ion pairs (2 IPs), in which many-body and same-ion interactions are included. Routinely used cations, of the imidazolium and pyrrolidinium families, were selected in the study coupled with chloride, tetrafluoroborate, and dicyanamide. Their two ion pair clusters were subjected to extensive configuration screening to establish most stable structures. Interaction energies of these clusters were calculated at the spin-ratio scaled MP2 (SRS-MP2) level for the correlation interaction energy, and a newly developed scaled Hartree-Fock method for the rest of energetic contributions to interaction energy. A full geometry screening for each cation-anion combination resulted in 192 unique structures, whose stability was assessed using two criteria—widely used interaction energy and total electronic energy. Furthermore, the ratio of interaction energy to its dispersion component was correlated with experimentally observed melting points in 64 energetically favourable structures. These systems were also used to test the correlation of the dispersion contribution to interaction energy with measured conductivity.
Chiappisi, Leonardo; Gradzielski, Michael
2015-06-01
In this review, different aspects characterizing chitosan-surfactant mixtures are summarized and compared. Chitosan is a bioderived cationic polysaccharide that finds wide-ranged applications in various field, e.g., medical or food industry, in which synergistic effects with surfactant can play a fundamental role. In particular, the behavior of chitosan interacting with strong and weak anionic, nonionic as well as cationic surfactants is reviewed. We put a focus on oppositely charged systems, as they exhibit the most interesting features. In that context, we discuss the thermodynamic description of the interaction and in particular the structural changes as they occur as a function of the mixed systems and external parameters. Moreover, peculiar properties of chitosan coated phospholipid vesicles are summarized. Finally, their co-assembly at interfaces is briefly reviewed. Despite the behavior of the mentioned systems might strongly differ, resulting in a high variety of properties, few general rules can be pointed out which improve the understanding of such complex systems. Copyright © 2015 Elsevier B.V. All rights reserved.
Thermodynamic and structure-property study of liquid-vapor equilibrium for aroma compounds.
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.
Mechanical, dynamical and thermodynamic properties of Al-3wt%Mg from first principles
Energy Technology Data Exchange (ETDEWEB)
Yang, Rong [Chongqing Jiaotong Univ., Chongqing (China). College of Materials Science and Engineering; Tang, Bin [Chongqing City Management College, Chongqing (China). Inst. of Finance and Trade; Gao, Tao [Sichuan Univ., Chengdu (China). Inst. of Atomic and Molecular Physics
2017-09-01
The mechanical, dynamical and thermodynamic properties of Al-3wt%Mg have been investigated using the first-principles method. The calculated structural parameter is in good agreement with previous works. Results for the elastic modulus, stress-strain relationships, ideal tensile and shear strengths are presented. Al-3wt%Mg is found to have larger moduli and higher strengths than Al, which is consistent with its exploitation in Al precipitate-hardening mechanisms. The partial density of states (PDOS) show that the partly covalent-like bonding through Al p-Mg s hybridization is the origin of excellent mechanical properties of Al-3wt%Mg. The phonon dispersion curves indicate that Al-3wt%Mg is dynamically stable at ambient pressure and 0 K. Furthermore, the Helmholtz free energy ΔF, the entropy S, the constant-volume specific heat C{sub V} and the phonon contribution to the internal energy ΔE are predicted using the phonon density of states. We expect that our work can provide useful guidance to help with the performance of Al-3wt%Mg.
R134a Flow Boiling Analysis with Modified Thermodynamic Property File of MARS Code
Energy Technology Data Exchange (ETDEWEB)
Son, Gyumin; Bang, In Cheol [UNIST, Ulsan (Korea, Republic of)
2016-10-15
Previous study showed application of RELAP5 code to solar energy facility with molten salt (60% NaNO3 and 40% KNO3) as working fluid. Based on external experimental correlations, thermodynamic properties of molten salt were evaluated as a function of pressure and temperature and those equations were used to generate tpf. To validate external tpf, experimental values were compared with RELAP5 analysis. In nuclear field, utilization of other fluid is also important since many thermal-hydraulic experiments used various fluids such as FC-72, R123, and R134a. Theses refrigerants have been used to simulate the high pressure environment of nuclear power plants due to their low boiling point, and density ratio between vapor and liquid. Thus, this study aims for tpf generation of R134a and verification by analyzing real case. R134a is selected as a fluid to be implemented and analyzed because it is currently used in refrigerator and frequently used in flow boiling experiment related with heat transfer coefficient and CHF measurement. R134a property file were generated with fitted equation using temperature and pressure as variables, originated from external data source. For validation, flow boiling experiment case were made into simplified input. Analysis with tpfr134a showed that application of Gnielinksi correlation could enhance single phase flow accuracy. Large error of HTC from two phase analysis requires parameter study. Future work aims for more specified experimental case comparison and correlation enhancement for two phase analysis.
First principles calculation of thermodynamic properties of NaAlSi ternary
International Nuclear Information System (INIS)
Qin Jining; Lu Weijie; Zhang Di; Fan Tongxiang
2012-01-01
PbFCl-type NaAlSi ternary is a corrosion compound found in aluminum, which is used as a sealing material in sodium sulfur battery. To understand and control the corrosion process, it is important to predict its quantitative properties. In this study, a first-principles calculation has been carried out to calculate its equilibrium lattice parameters, bulk modulus and pressure derivative of bulk modulus by both all-electron full-potential linear augmented plane wave scheme and pseudopotential plane wave scheme within the generalized gradient approximation. The theoretical results show good agreement with the available experimental data. The thermodynamic properties, including the specific heat capacity and entropy with pressure up to 9 GPa, have been investigated for the first time by coupling of density functional perturbation theory and quasiharmonic approximation. The volume and linear thermal expansion coefficients were estimated and the results show that the linear thermal expansion on c-axis is nearly twice as large as that on a-axis within the calculated temperature.
Atomistic simulations of thermodynamic properties of Xe gas bubbles in U10Mo fuels
Hu, Shenyang; Setyawan, Wahyu; Joshi, Vineet V.; Lavender, Curt A.
2017-07-01
Xe gas bubble superlattice formation is observed in irradiated uranium-10 wt% molybdenum (U10Mo) fuels. However, the thermodynamic properties of the bubbles (the relationship among bubble size, equilibrium Xe concentration, and bubble pressure) and the mechanisms of bubble superlattice formation are not well known. In this work, the molecular dynamics (MD) method is used to study these properties and mechanisms. The results provide important inputs for quantitative mesoscale models of gas bubble evolution and fuel performance. In the MD simulations, the embedded-atom method (EAM) potential of U10Mo-Xe [1] is employed. Initial gas bubbles with a low Xe concentration (underpressured) are generated in a body-centered cubic (bcc) U10Mo single crystal. Then Xe atoms are sequentially added into the bubbles one by one, and the evolution of pressure and dislocation emission around the bubbles is analyzed. The relationship between pressure, equilibrium Xe concentration, and radius of the bubbles is established. It was found that an overpressured gas bubble emits partial dislocations with a Burgers vector along the direction and a slip plane of (11-2). Meanwhile, dislocation loop punch out was not observed. The overpressured bubble also induces an anisotropic stress field. A tensile stress was found along directions around the bubble, favoring the nucleation and formation of a face-centered cubic bubble superlattice in bcc U10Mo fuels.
Directory of Open Access Journals (Sweden)
Zonghua Wang
2013-05-01
Full Text Available Doxorubicin hydrochloride (DOX is an effective anticancer agent for leukemia chemotherapy, although its clinical use has been limited because of its side effects such as cardiotoxicity, alopecia, vomiting, and leucopenia. Attention has been focussed on developing new drug carriers with high adsorption capacity and rapid adsorption rate in order to minimize the side effects of DOX. Graphene oxide (GO, a new type of nanomaterial in the carbon family, was prepared by Hummers method and used as adsorbent for DOX from aqueous solution. The physico-chemical properties of GO were characterized by transmission electron microscope (TEM, Fourier transform infrared spectroscopy (FTIR, zeta potential, and element analysis. The adsorption properties of DOX on GO were studied as a function of contact time, adsorbent dosage, temperature and pH value. The results showed that GO had a maximum adsorption capacity of 1428.57 mg/g and the adsorption isotherm data fitted the Langmuir model. The kinetics of adsorption fits a pseudo-second-order model. The thermodynamic studies indicate that the adsorption of DOX on GO is spontaneous and endothermic in nature.
Mechanical, dynamical and thermodynamic properties of Al-3wt%Mg from first principles
International Nuclear Information System (INIS)
Yang, Rong; Tang, Bin; Gao, Tao
2017-01-01
The mechanical, dynamical and thermodynamic properties of Al-3wt%Mg have been investigated using the first-principles method. The calculated structural parameter is in good agreement with previous works. Results for the elastic modulus, stress-strain relationships, ideal tensile and shear strengths are presented. Al-3wt%Mg is found to have larger moduli and higher strengths than Al, which is consistent with its exploitation in Al precipitate-hardening mechanisms. The partial density of states (PDOS) show that the partly covalent-like bonding through Al p-Mg s hybridization is the origin of excellent mechanical properties of Al-3wt%Mg. The phonon dispersion curves indicate that Al-3wt%Mg is dynamically stable at ambient pressure and 0 K. Furthermore, the Helmholtz free energy ΔF, the entropy S, the constant-volume specific heat C_V and the phonon contribution to the internal energy ΔE are predicted using the phonon density of states. We expect that our work can provide useful guidance to help with the performance of Al-3wt%Mg.
Superposition and macroscopic observation
International Nuclear Information System (INIS)
Cartwright, N.D.
1976-01-01
The principle of superposition has long plagued the quantum mechanics of macroscopic bodies. In at least one well-known situation - that of measurement - quantum mechanics predicts a superposition. It is customary to try to reconcile macroscopic reality and quantum mechanics by reducing the superposition to a mixture. To establish consistency with quantum mechanics, values for the apparatus after a measurement are to be distributed in the way predicted by the superposition. The distributions observed, however, are those of the mixture. The statistical predictions of quantum mechanics, it appears, are not borne out by observation in macroscopic situations. It has been shown that, insofar as specific ergodic hypotheses apply to the apparatus after the interaction, the superposition which evolves is experimentally indistinguishable from the corresponding mixture. In this paper an idealized model of the measuring situation is presented in which this consistency can be demonstrated. It includes a simplified version of the measurement solution proposed by Daneri, Loinger, and Prosperi (1962). The model should make clear the kind of statistical evidence required to carry of this approach, and the role of the ergodic hypotheses assumed. (Auth.)
Energy Technology Data Exchange (ETDEWEB)
Grachev, Valentin G.; Vrable, Ian A.; Malovichko, Galina I. [Physics Department, Montana State University, Bozeman, Montana 59717 (United States); Pritula, Igor M.; Bezkrovnaya, Olga N.; Kosinova, Anna V. [Institute for Single Crystals, NAS of Ukraine, Kharkiv (Ukraine); Yatsyna, Vasyl O.; Gayvoronsky, Vladimir Ya. [Institute of Physics, NAS of Ukraine, 03680 Kiev (Ukraine)
2012-07-01
Results from the successful growth of high quality KH{sub 2}PO{sub 4} (KDP) crystals with incorporated TiO{sub 2} anatase nanoparticles and the characterization of these crystals using several complementary methods are presented. The study allowed the nature and distribution of macroscopic and microscopic defects in the KDP:TiO{sub 2} crystals to be clarified. The relationship between these defects and the distribution of TiO{sub 2} nanoparticles, and the influence of incorporated nanoparticles on the nonlinear optical properties of composite crystals in comparison with pure crystals were also elucidated. Visual observations, transmission and scanning electron microscopy have shown that the anatase nanoparticles were captured mainly by the pyramidal growth sector and, to a considerably lesser extent, by the prismatic growth sector. Energy dispersive x-ray analysis was able to confirm that the growth layer stacks contain the TiO{sub 2} particles. Fourier transformation infrared spectra have clearly shown the presence of an absorption band at about 800 cm{sup -1} in both KDP:TiO{sub 2} and TiO{sub 2}, and the disappearance of the band, associated with hydroxyl OH{sup -} groups on the TiO{sub 2} surface in KDP:TiO{sub 2}. Significant variation in the imaginary and real parts of the cubic nonlinear optical susceptibilities and refractive index changes at continuous wave excitation were found in prism and pyramid parts of pure KDP and KDP:TiO{sub 2} samples. Deciphering complicated electron paramagnetic resonance spectra in KDP:TiO{sub 2} and comparison with published data permitted the identification of paramagnetic defects along with their associated g-factors and zero-field splitting parameters (in some cases for the first time). It was found that the dominant lines belong to four different centers Fe{sub A}{sup 3+}, Fe{sub B}{sup 3+}, Cr{sub R}{sup 3+}, and Cr{sub GB}{sup 3+}. From analysis of line intensities it was concluded that the concentration of intrinsic
International Nuclear Information System (INIS)
Yang Xi; Liu Hui; Hou Haifeng; Flamm, Alison; Zhang Xuesheng; Wang Zunyao
2010-01-01
The thermodynamic properties of 75 polyfluorinated dibenzo-p-dioxins (PFDDs) in the ideal gas state at 298.15 K and 1.013 x 10 5 Pa have been calculated at the B3LYP/6-311G* level using Gaussian 03 program. The isodesmic reactions were designed to calculate standard enthalpy of formation (ΔH f o ) and standard free energy of formation (ΔG f o ) of PFDDs congeners. The relations of these thermodynamic parameters with the number and position of fluorine atom substitution (N PFS ) were discussed, and it was found that there exist high correlations between thermodynamic parameters (entropy (S o ), ΔH f o and ΔG f o ) and N PFS . According to the relative magnitude of their ΔG f o , the relative stability order of PFDD congeners was theoretically proposed.
Smirnov, N. A.
2018-03-01
The paper investigates the role of spin-orbit interaction in the prediction of structural stability, lattice dynamics, elasticity, thermodynamic and transport properties (electrical resistivity and thermal conductivity) of lead under pressure with the FP-LMTO (full-potential linear-muffin-tin orbital) method for the first-principles band structure calculations. Our calculations were carried out for three polymorphous lead modifications (fcc, hcp, and bcc) in generalized gradient approximation with the exchange-correlation functional PBEsol. They suggest that compared to the scalar-relativistic calculation, the account for the SO effects insignificantly influences the compressibility of Pb. At the same time, in the calculation of phonon spectra and transport properties, the role of SO interaction is important, at least, for P ≲150 GPa. At higher pressures, the contribution from SO interaction reduces but not vanishes. As for the relative structural stability, our studies show that SO effects influence weakly the pressure of the fcc →hcp transition and much higher the pressure of the hcp →bcc transition.
Electronic, magnetic, elastic and thermodynamic properties of Cu{sub 2}MnGa
Energy Technology Data Exchange (ETDEWEB)
Ghosh, Sukriti [Department of Physics, Government Kamla Raja Girls Autonomous Post Graduate College, Gwalior 474001, Madhya Pradesh (India); Condensed Matter Theory Group, School of Studies in Physics, Jiwaji University, Gwalior 474 011, Madhya Pradesh (India); Gupta, Dinesh C., E-mail: sosfizix@gmail.com [Condensed Matter Theory Group, School of Studies in Physics, Jiwaji University, Gwalior 474 011, Madhya Pradesh (India)
2016-08-01
The full-potential linearized augmented plane wave method in the stable Fm-3m phase has been implemented to investigate the structural, elastic, magnetic and electronic properties of Cu{sub 2}MnGa. The optimized equilibrium lattice parameter in stable phase is found to be 5.9495 Å. By the spin resolved density of states calculations, we have shown that the exchange splitting due to Mn atom is the main reason of ferromagnetic behavior of Cu{sub 2}MnGa. The absence of energy gap in both the spin channels predicts that the material is metallic. The total and partial density of states, elastic constants, Shear, Bulk and Young’s moduli, Zener isotropy factor, Cauchy pressure, Pugh's ductility, Kleinman parameter and Poisson's ratio are reported for the first time for the alloy. Cauchy's pressure and Pugh's index of ductility label Cu{sub 2}MnGa as ductile. Cu{sub 2}MnGa is found to be ferromagnetic and anisotropic in nature. The quasi-harmonic approximations have been employed to study the pressure and temperature dependent thermodynamic properties of Cu{sub 2}MnGa. - Highlights: • It is the first attempt to predict a variety of crystal properties of Cu{sub 2}MnGa. • Cu{sub 2}MnGa shows magnetism and hence can prove to be important in modern technology. • Cu{sub 2}MnGa is ductile and hence can attract attention of scientists and technologists.
International Nuclear Information System (INIS)
Ali, M A; Nasir, M T; Khatun, M R; Naqib, S H; Islam, A K M A
2016-01-01
The structural vibrational, thermodynamical, and optical properties of potentially technologically important, weakly coupled MAX compound, Sc 2 AlC are calculated using density functional theory (DFT). The structural properties of Sc 2 AlC are compared with the results reported earlier. The vibrational, thermodynamical, and optical properties are theoretically estimated for the first time. The phonon dispersion curve is calculated and the dynamical stability of this compound is investigated. The optical and acoustic modes are observed clearly. We calculate the Helmholtz free energy ( F ), internal energy ( E ), entropy ( S ), and specific heat capacity ( C v ) from the phonon density of states. Various optical parameters are also calculated. The reflectance spectrum shows that this compound has the potential to be used as an efficient solar reflector. (paper)
Directory of Open Access Journals (Sweden)
Gulebaglan Sinem Erden
2015-01-01
Full Text Available We performed first-principles calculations to obtain the electronic, optical, elastic, lattice-dynamical and thermodynamic properties of RbH compound with rock salt structure. The ground-state properties, i.e., the lattice constant and the band gap were investigated using a plane wave pseudopotential method within density functional theory. The calculated lattice constant, bulk modulus, energy band gap and elastic constants are reported and compared with previous theoretical and experimental results. Our calculated results and the previous results which are obtained from literature are in a good agreement. Moreover, real and imaginary parts of complex dielectric function, reflectivity spectrum, absorption, extinction coefficient and loss function as a function of photon energy and refractive index with respect to photon wavelength were calculated. In addition, temperature dependent thermodynamic properties such as Helmholtz free energy, internal energy, entropy and specific heat have been studied.
Directory of Open Access Journals (Sweden)
Bingol Suat
2015-01-01
Full Text Available The geometric structural optimization, electronic band structure, total density of states for valence electrons, density of states for phonons, optical, dynamical, and thermodynamical features of cesium chloride have been investigated by linearized augmented plane wave method using the density functional theory under the generalized gradient approximation. Ground state properties of cesium chloride are studied. The calculated ground state properties are consistent with experimental results. Calculated band structure indicates that the cesium chloride structure has an indirect band gap value of 5.46 eV and is an insulator. From the obtained phonon spectra, the cesium chloride structure is dynamically stable along the various directions in the Brillouin zone. Temperature dependent thermodynamic properties are studied using the harmonic approximation model.
Assessment of the thermodynamic properties and phase diagram of the Bi–Pd system
Czech Academy of Sciences Publication Activity Database
Vřešťál, J.; Pinkas, J.; Watson, A.; Scott, A.; Houserová, Jana; Kroupa, Aleš
2006-01-01
Roč. 30, č. 1 (2006), s. 14-17 ISSN 0364-5916 R&D Projects: GA MŠk(CZ) OC 531.002 Institutional research plan: CEZ:AV0Z2041904 Keywords : phase diagram * thermodynamic modelling Subject RIV: BJ - Thermodynamics Impact factor: 1.432, year: 2006
Modeling and experimental verification of the thermodynamic properties of hydrogen storage materials
Ledovskikh, A.V.; Danilov, D.L.; Vliex, M.F.H.; Notten, P.H.L.
2016-01-01
A new mathematical model has been developed describing the thermodynamics of the hydrogen absorption and desorption process in Metal Hydrides via the gas phase. This model is based on first principles chemical and statistical thermodynamics and takes into account structural changes occurring inside
Are the Laws of Thermodynamics Consequences of a Fractal Properties of Universe?
Kobelev, L. Ya.
2000-01-01
Why in our Universe the laws of thermodynamics are valid? In the paper is demonstrated the reason of it: if the time and the space are multifractal and the Universe is in an equilibrium state the laws of the thermodynamics are consequences of it's multifractal structure.
Li, Huaming; Tian, Yanting; Sun, Yongli; Li, Mo; Nonequilibrium materials; physics Team; Computational materials science Team
In this work, we apply a general equation of state of liquid and Ab initio molecular-dynamics method to study thermodynamic properties in liquid potassium under high pressure. Isothermal bulk modulus and molar volume of molten sodium are calculated within good precision as compared with the experimental data. The calculated internal energy data and the calculated values of isobaric heat capacity of molten potassium show the minimum along the isothermal lines as the previous result obtained in liquid sodium. The expressions for acoustical parameter and nonlinearity parameter are obtained based on thermodynamic relations from the equation of state. Both parameters for liquid potassium are calculated under high pressure along the isothermal lines by using the available thermodynamic data and numeric derivations. Furthermore, Ab initio molecular-dynamics simulations are used to calculate some thermodynamic properties of liquid potassium along the isothermal lines. Scientific Research Starting Foundation from Taiyuan university of Technology, Shanxi Provincial government (``100-talents program''), China Scholarship Council and National Natural Science Foundation of China (NSFC) under Grant No. 51602213.
Wu, Yi; Wang, Chunlin; Sun, Hao; Murphy, Anthony B.; Rong, Mingzhe; Yang, Fei; Chen, Zhexin; Niu, Chunpin; Wang, Xiaohua
2018-04-01
The thermophysical properties, including composition, thermodynamic properties, transport coefficients and net emission coefficients, of thermal plasmas formed from pure iso-C4 perfluoronitrile C4F7N and C4F7N–CO2 mixtures are calculated for temperatures from 300 to 30 000 K and pressures from 0.1 to 20 atm. These gases have received much attention as alternatives to SF6 for use in circuit breakers, due to the low global warming potential and good dielectric properties of C4F7N. Since the parameters of the large molecules formed in the dissociation of C4F7N are unavailable, the partition function and enthalpy of formation were calculated using computational chemistry methods. From the equilibrium composition calculations, it was found that when C4F7N is mixed with CO2, CO2 can capture C atoms from C4F7N, producing CO, since the system consisting of small molecules such as CF4 and CO has lower energy at room temperature. This is in agreement with previous experimental results, which show that CO dominates the decomposition products of C4F7N–CO2 mixtures; it could limit the repeated breaking performance of C4F7N. From the point of view of chemical stability, the mixing ratio of CO2 should therefore be chosen carefully. Through comparison with common arc quenching gases (including SF6, CF3I and C5F10O), it is found that for the temperature range for which electrical conductivity remains low, pure C4F7N has similar ρC p (product of mass density and specific heat) properties to SF6, and higher radiative emission coefficient, properties that are correlated with good arc extinguishing capability. For C4F7N–CO2 mixtures, the electrical conductivity is very close to that of SF6 while the ρC p peak at 7000 K caused by decomposition of CO implies inferior interruption capability to that of SF6. The calculated properties will be useful in arc simulations.
Directory of Open Access Journals (Sweden)
Ana Paula Prette
2013-03-01
Full Text Available The Jackfruit tree is one of the most significant trees in tropical home gardens and perhaps the most widespread and useful tree in the important genus Artocarpus. The fruit is susceptible to mechanical and biological damage in the mature state, and some people find the aroma of the fruit objectionable, particularly in confined spaces. The dehydration process could be an alternative for the exploitation of this product, and the relationship between moisture content and water activity provides useful information for its processing and storage. The aim of this study was to determine the thermodynamic properties of the water sorption of jackfruit (Artocarpus heterophyllus Lam. as a function of moisture content. Desorption isotherms of the different parts of the jackfruit (pulp, peduncle, mesocarp, peel, and seed were determined at four different temperatures (313.15, 323.15, 333.15, and 343.15 K in a water activity range of 0.02-0.753 using the static gravimetric method. Theoretical and empirical models were used to model the desorption isotherms. An analytical solution of the Clausius-Clapeyron equation was proposed to calculate the isosteric heat of sorption, the differential entropy, and Gibbs' free energy using the Guggenhein-Anderson-de Boer and Oswin models considering the effect of temperature on the hygroscopic equilibrium.
Directory of Open Access Journals (Sweden)
Li Zuo Taitano
2012-04-01
Full Text Available Moisture adsorption characteristics of California grown almonds (Nonpareil: pasteurized and unpasteurized almonds; Monterey: pasteurized, unpasteurized and blanched almonds were obtained using the gravimetric method over a range of water activities from 0.11 to 0.98 at 7-50ºC. The weights of almonds were measured until samples reached a constant weight. The relationship between equilibrium moisture content and water activity was established using the Guggenheim-Anderson-de Boer model. The diffusion coefficient of water in almond kernels was calculated based on Ficks second law. The monolayer moisture value of almonds ranged from 0.020 to 0.035 kg H2O kg-1 solids. The diffusion coefficient increased with temperature at a constant water activity, and decreased with water activity at a constant temperature. The thermodynamic properties (net isosteric heat, differential enthalpy and entropy were also determined. The net isosteric heat of adsorption decreased with the increasing moisture content, and the plot of differential enthalpy versus entropy satisfied the enthalpy-entropy compensation theory. The adsorption process of almond samples was enthalpy driven over the range of studied moisture contents.
Quantum phase transition and thermodynamic properties of a fourfold magnetic periodic system
Energy Technology Data Exchange (ETDEWEB)
Wang, Shuling, E-mail: wangshuling0324.student@sina.com [School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074 (China); Li, Ruixue [School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074 (China); Ding, Linjie [Department of Physics, China Three Gorges University, Yi Chang 443002 (China); Fu, Hua-Hua; Zhu, Si-cong [School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074 (China); Ni, Yun [Huazhong University of Science and Technology, Wenhua College, Wuhan 430074 (China); Meng, Yan [Department of Physics, Xingtai University, Xingtai 054001 (China); Yao, Kailun [School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074 (China); International Center of Materials Physics, Chinese Academy of Science, Shenyang 110015 (China)
2014-12-15
Based on the experimental synthesis of organic compound verdazyl radical β-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. - Highlights: • The antiferromagnetic interaction-magnetic field phase diagrams are constructed. • The magnetization per site makes different contribution to the 1/2 plateau. • The spectral functions for different magnetic interactions are studied. • We investigate the gapless or gapped low-lying excitations at low temperatures.
Modeling of thermodynamic properties of refrigerant/absorbent couples using data mining process
International Nuclear Information System (INIS)
Sencan, Arzu
2007-01-01
In this paper, in order to determine thermodynamic properties of two alternative refrigerant/absorbent couples (methanol/LiBr and methanol/LiCl), a data mining process was used. These fluid couples can be used in absorption heat pump systems, and their main advantage is that they do not cause ozone depletion. In order to train the network, limited experimental measurements were used as training and test data. In the present study, linear regression (LR), pace regression (PR), sequential minimal optimization (SMO), M5 model tree, M5'Rules and back propagation neural network (BPNN) models are applied within the data mining process for determining the specific volume of the methanol/LiBr and methanol/LiCl fluid couples. The best result was obtained by using the back propagation model. A new formulation is presented for determination of the specific volumes of the two refrigerant/absorbent couples. The use of this new formulation, which can be employed with any programming language or spreadsheet program for estimation of the specific volumes of fluid couples, as described in this paper, may make the use of dedicated BPNN software unnecessary
Thermodynamic properties of 1-ethyl-4-nitro-1,2,3-triazole
International Nuclear Information System (INIS)
Blokhin, Andrey V.; Kohut, Sviataslau V.; Kabo, Gennady J.; Stepurko, Elena N.; Paulechka, Yauheni U.; Voitkevich, Olga V.
2013-01-01
Graphical abstract: - Highlights: • Heat capacities and phase transition enthalpies for 1-ethyl-4-nitro-1,2,3-triazole were measured. • Enthalpy of formation for 1-ethyl-4-nitro-1,2,3-triazole was determined. • Vapor pressure and enthalpy of sublimation of 1-ethyl-4-nitro-1,2,3-triazole were found from Knudsen measurements. - Abstract: Temperature dependence of the heat capacity and the parameters of phase transitions of 1-ethyl-4-nitro-1,2,3-triazole (1ET) were studied between 5 and 370 K in a vacuum adiabatic calorimeter. Thermodynamic properties of the 1ET in the condensed state were obtained over the range of 0–370 K. Saturated vapor pressure for crystalline 1ET in the temperature ranges from 313 to 344 K and its enthalpy of sublimation were measured by the Knudsen effusion method. The standard enthalpy of formation for crystalline 1ET at 298.15 K was determined in a static bomb combustion calorimeter. From these data, the standard enthalpy of formation for gaseous 1ET was evaluated. The enthalpy of formation calculated using quantum chemical methods is in excellent agreement with the experimental value
Energy Technology Data Exchange (ETDEWEB)
Dubey, Gyan Prakash, E-mail: gyan.dubey@rediffmail.com [Department of Chemistry, Kurukshetra University, Kurukshetra 136119 (India); Kumar, Krishan [Department of Chemistry, Kurukshetra University, Kurukshetra 136119 (India)
2011-09-20
Highlights: {yields} Thermodynamic study of diethylenetriamine + 2-methyl-1-propanol, +2-propanol or +1-butanol have been made. {yields} Excess molar volumes and isentropic compressibility were determined. {yields} Types of interactions were discussed based on derived properties. - Abstract: Densities, {rho}, viscosities, {eta}, and speeds of sound, u, were measured for the binary liquid mixtures containing diethylenetriamine with 2-methyl-1-propanol, 2-propanol and 1-butanol at 293.15, 298.15, 303.15, 308.15 and 313.15 K. From density and speed of sound data, excess molar volumes, V{sub m}{sup E} and deviations in isentropic compressibility, {Delta}{kappa}{sub s}, and speed of sound, {Delta}u have been evaluated. Viscosity data were used to compute deviations in viscosity and excess Gibbs energy of activation of viscous flow {Delta}G*{sup E} at 298.15, 303.15 and 308.15 K. A Redlich-Kister type equation was applied to fit the excess molar volumes and deviations in isentropic compressibility, speed of sound and viscosity data. The viscosity data have been correlated with the equations of Grunberg-Nissan, Tamura-Kurata, Heric-Brewer and of Hind et al. All the binary systems of the present study have negative values of excess molar volumes and deviations in isentropic compressibility over whole composition range and at all temperatures which indicates strong interactions between the components of binary mixtures.
International Nuclear Information System (INIS)
Dubey, Gyan Prakash; Kumar, Krishan
2011-01-01
Highlights: → Thermodynamic study of diethylenetriamine + 2-methyl-1-propanol, +2-propanol or +1-butanol have been made. → Excess molar volumes and isentropic compressibility were determined. → Types of interactions were discussed based on derived properties. - Abstract: Densities, ρ, viscosities, η, and speeds of sound, u, were measured for the binary liquid mixtures containing diethylenetriamine with 2-methyl-1-propanol, 2-propanol and 1-butanol at 293.15, 298.15, 303.15, 308.15 and 313.15 K. From density and speed of sound data, excess molar volumes, V m E and deviations in isentropic compressibility, Δκ s , and speed of sound, Δu have been evaluated. Viscosity data were used to compute deviations in viscosity and excess Gibbs energy of activation of viscous flow ΔG* E at 298.15, 303.15 and 308.15 K. A Redlich-Kister type equation was applied to fit the excess molar volumes and deviations in isentropic compressibility, speed of sound and viscosity data. The viscosity data have been correlated with the equations of Grunberg-Nissan, Tamura-Kurata, Heric-Brewer and of Hind et al. All the binary systems of the present study have negative values of excess molar volumes and deviations in isentropic compressibility over whole composition range and at all temperatures which indicates strong interactions between the components of binary mixtures.
International Nuclear Information System (INIS)
Fang Zheng; Zhang Quanru
2006-01-01
A model has been derived to predict thermodynamic properties of ternary metallic systems from those of its three binaries. In the model, the excess Gibbs free energies and the interaction parameter ω 123 for three components of a ternary are expressed as a simple sum of those of the three sub-binaries, and the mole fractions of the components of the ternary are identical with the sub-binaries. This model is greatly simplified compared with the current symmetrical and asymmetrical models. It is able to overcome some shortcomings of the current models, such as the arrangement of the components in the Gibbs triangle, the conversion of mole fractions between ternary and corresponding binaries, and some necessary processes for optimizing the various parameters of these models. Two ternary systems, Mg-Cu-Ni and Cd-Bi-Pb are recalculated to demonstrate the validity and precision of the present model. The calculated results on the Mg-Cu-Ni system are better than those in the literature. New parameters in the Margules equations expressing the excess Gibbs free energies of three binary systems of the Cd-Bi-Pb ternary system are also given
Thermodynamic properties of 1-ethyl-4-nitro-1,2,3-triazole
Energy Technology Data Exchange (ETDEWEB)
Blokhin, Andrey V., E-mail: blokhin@bsu.by; Kohut, Sviataslau V.; Kabo, Gennady J.; Stepurko, Elena N.; Paulechka, Yauheni U.; Voitkevich, Olga V.
2013-08-10
Graphical abstract: - Highlights: • Heat capacities and phase transition enthalpies for 1-ethyl-4-nitro-1,2,3-triazole were measured. • Enthalpy of formation for 1-ethyl-4-nitro-1,2,3-triazole was determined. • Vapor pressure and enthalpy of sublimation of 1-ethyl-4-nitro-1,2,3-triazole were found from Knudsen measurements. - Abstract: Temperature dependence of the heat capacity and the parameters of phase transitions of 1-ethyl-4-nitro-1,2,3-triazole (1ET) were studied between 5 and 370 K in a vacuum adiabatic calorimeter. Thermodynamic properties of the 1ET in the condensed state were obtained over the range of 0–370 K. Saturated vapor pressure for crystalline 1ET in the temperature ranges from 313 to 344 K and its enthalpy of sublimation were measured by the Knudsen effusion method. The standard enthalpy of formation for crystalline 1ET at 298.15 K was determined in a static bomb combustion calorimeter. From these data, the standard enthalpy of formation for gaseous 1ET was evaluated. The enthalpy of formation calculated using quantum chemical methods is in excellent agreement with the experimental value.
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).
Thermodynamics and elastic properties of Ir from first-principle calculations
International Nuclear Information System (INIS)
Li Qiang; Huang Duohui; Cao Qilong; Wang Fanhou
2013-01-01
Within the framework of the quasiharmonic approximation, the thermodynamics and elastic properties, including phonon dispersion curves, equation of state, linear thermal expansion coefficient and temperature-dependent entropy, enthalpy, heat capacity, elastic constants, bulk modulus, shear modulus, Young's modulus of Ir have been studied using first-principles projector-augmented wave method. The results revealed that the predicted phonon dispersion curves of Ir are in agreement with the experimental measurements by neutron diffractions. Considering the thermal electronic contribution to Helmholtz free energy, the calculated entropy, enthalpy, heat capacity and linear thermal expansion co- efficient from the first-principle are consistent well with the experimental data. At 2600 K, the electronic heat capacity accounts for 17% of the total heat capacity at constant pressure, thus the thermal electronic contribution to Helmholtz free energy is very important. The predicted elastic constants, bulk modulus, shear modulus and Young's modulus at room temperature are also in agreement with the available measurements and increase with the increasing temperature. (authors)
International Nuclear Information System (INIS)
Sencan, Arzu; Kalogirou, Soteris A.
2005-01-01
This paper presents a new approach using artificial neural networks (ANN) to determine the thermodynamic properties of two alternative refrigerant/absorbent couples (LiCl-H 2 O and LiBr + LiNO 3 + LiI + LiCl-H 2 O). These pairs can be used in absorption heat pump systems, and their main advantage is that they do not cause ozone depletion. In order to train the network, limited experimental measurements were used as training and test data. Two feedforward ANNs were trained, one for each pair, using the Levenberg-Marquardt algorithm. The training and validation were performed with good accuracy. The correlation coefficient obtained when unknown data were applied to the networks was 0.9997 and 0.9987 for the two pairs, respectively, which is very satisfactory. The present methodology proved to be much better than linear multiple regression analysis. Using the weights obtained from the trained network, a new formulation is presented for determination of the vapor pressures of the two refrigerant/absorbent couples. The use of this new formulation, which can be employed with any programming language or spreadsheet program for estimation of the vapor pressures of fluid couples, as described in this paper, may make the use of dedicated ANN software unnecessary
Thermodynamics Properties of Binary Gas Mixtures for Brayton Space Nuclear Power System
International Nuclear Information System (INIS)
You Ersheng; Shi Lei; Zhang Zuoyi
2014-01-01
Space nuclear power system with closed Brayton cycle has the potential advantages of high cycle efficiency. It can be achieved to limit the specific mass of the system with a competitive design scheme, so as to strengthen the advantage of the nuclear energy applying in space propulsion and electric generating compared to solar or chemical propellant. Whereby, the thermodynamic properties of working fluids have a significant influence on the performance of the plant. Therefore, two binary mixtures helium-nitrogen and helium-carbon dioxide are introduced to analysis the variation in the transport and heat transfer capacity of working fluids. Based on the parameters of pure gases, the heat transfer coefficient, pressure losses and aerodynamic loading are calculated as a function of mole fraction at the temperature of 400 K and 1200 K, as well as the typical operating pressure of 2 MPa. Results indicated that the mixture of helium-carbon dioxide with a mole fraction of 0.4 is a more attractive choice for the high heat transfer coefficient, low aerodynamic loading and acceptable pressure losses in contrast to helium-nitrogen and other mixing ratios of helium-carbon dioxide. Its heat transfer coefficient is almost 20% more than that of pure helium and the normalized aerodynamic loading is less than 34% at 1200 K. However; the pressure losses are a little higher with ~3.5 times those of pure helium. (author)
Directory of Open Access Journals (Sweden)
Cristian F. Costa
2016-06-01
Full Text Available ABSTRACT Jabuticaba is a fruit native of Brazil and, besides containing many nutritional qualities, it also has a good field for use in products such as flour for cakes and biscuits, juice, liqueur, jelly and others. This study aimed to model the drying kinetics and determine the thermodynamic properties of jabuticaba peel at different drying air temperatures. Ripe fruits of jabuticaba (Myrciaria jaboticaba were collected and pulped manually. Drying was carried out in a forced-air circulation oven with a flow of 5.6 m s-1 at temperatures of 40, 50, 60 and 70 °C. Six mathematical models commonly used to represent the drying process of agricultural products were fitted to the experimental data. The Arrhenius model was used to represent the drying constant as a function of temperature. The Midilli model showed the best fit to the experimental data of drying. The drying constant increased with the increment in drying temperature and promoted an activation energy of 37.29 kJ mol-1. Enthalpy and Gibbs free energy decreased with the increase in drying temperature, while entropy decreased and was negative.
Thermodynamic properties and cloud droplet activation of a series of oxo-acids
Directory of Open Access Journals (Sweden)
M. Frosch
2010-07-01
Full Text Available We have investigated the thermodynamic properties of four aliphatic oxo-dicarboyxlic acids identified or thought to be present in atmospheric particulate matter: oxosuccinic acid, 2-oxoglutaric acid, 3-oxoglutaric acid, and 4-oxopimelic acid. The compounds were characterized in terms of their cloud condensation nuclei (CCN activity, vapor pressure, density, and tendency to decarboxylate in aqueous solution. We deployed a variety of experimental techniques and instruments: a CCN counter, a Tandem Differential Mobililty Analyzer (TDMA coupled with a laminar flow-tube, and liquid chromatography/mass spectrometry (LC/MS. The presence of the oxo functional group in the α-position causes the vapor pressure of the compounds to diminish by an order of magnitude with respect to the parent dicarboxylic acid, while the CCN activity is similar or increased. Dicarboxylic acids with an oxo-group in the β-position decarboxylate in aqueous solution. We studied the effects of this process on our measurements and findings.
Thermodynamic properties of calcium–bismuth alloys determined by emf measurements
International Nuclear Information System (INIS)
Kim, Hojong; Boysen, Dane A.; Bradwell, David J.; Chung, Brice; Jiang Kai; Tomaszowska, Alina A.; Wang Kangli; Wei Weifeng; Sadoway, Donald R.
2012-01-01
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)|CaF 2 (s)|Ca(in Bi) cell for twenty different Ca–Bi alloys spanning the entire range of composition from x 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 of a Ca = 1 × 10 −8 over the composition range x Ca = 0.32–0.56, yielding an emf of ∼0.77 V. Above x Ca = 0.62 and coincident with Ca 5 Bi 3 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.
Thermodynamic Properties of a Double Ring-Shaped Quantum Dot at Low and High Temperatures
Khordad, R.; Sedehi, H. R. Rastegar
2018-02-01
In this work, we study thermodynamic properties of a GaAs double ring-shaped quantum dot under external magnetic and electric fields. To this end, we first solve the Schrödinger equation and obtain the energy levels and wave functions, analytically. Then, we calculate the entropy, heat capacity, average energy and magnetic susceptibility of the quantum dot in the presence of a magnetic field using the canonical ensemble approach. According to the results, it is found that the entropy is an increasing function of temperature. At low temperatures, the entropy increases monotonically with raising the temperature for all values of the magnetic fields and it is independent of the magnetic field. But, the entropy depends on the magnetic field at high temperatures. The entropy also decreases with increasing the magnetic field. The heat capacity and magnetic susceptibility show a peak structure. The heat capacity reduces with increasing the magnetic field at low temperatures. The magnetic susceptibility shows a transition between diamagnetic and paramagnetic below for T<4 K. The transition temperature depends on the magnetic field.
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.
International Nuclear Information System (INIS)
Durán-Zenteno, Moisés S.; Pérez-López, Hugo I.; Galicia-Luna, Luis A.; Elizalde-Solis, Octavio
2012-01-01
Highlights: ► We measured densities for {alkanol (ethanol or 1-propanol) + boldine} mixtures. ► Liquid densities are reported in the ranges of (1 to 20) MPa and (313 to 363) K. ► Thermodynamic derived properties were calculated using an empirical correlation. ► Extrapolated densities at atmospheric pressure agree with the literature data. - Abstract: In this work, densities of two binary systems of {alkanol (ethanol and 1-propanol) + boldine} are measured at temperatures from (313 to 363) K and pressures up to 20 MPa using an Anton Paar vibrating tube densimeter. Each (alkanol + boldine) system was prepared at five diluted compositions with respect to the alkaloid. These are (x 2 = 0.0012, 0.0074, 0.0136, 0.0196, 0.0267) and (x 2 = 0.0018, 0.0046, 0.0077, 0.0112, 0.0142) mixed in ethanol and 1-propanol, respectively. Experimental densities are correlated using an empirical 6-parameter equation with deviations within 0.04%. Extrapolated densities at atmospheric pressure agree with the literature data. Isobaric expansivity, isothermal compressibility, thermal pressure coefficient, and internal pressure have been calculated.
Harikrishnan, A R; Dhar, Purbarun; Gedupudi, Sateesh; Das, Sarit K
2018-04-12
We propose a comprehensive analysis and a quasi-analytical mathematical formalism to predict the surface tension and contact angles of complex surfactant-infused nanocolloids. The model rests on the foundations of the interaction potentials for the interfacial adsorption-desorption dynamics in complex multicomponent colloids. Surfactant-infused nanoparticle-laden interface problems are difficult to deal with because of the many-body interactions and interfaces involved at the meso-nanoscales. The model is based on the governing role of thermodynamic and chemical equilibrium parameters in modulating the interfacial energies. The influence of parameters such as the presence of surfactants, nanoparticles, and surfactant-capped nanoparticles on interfacial dynamics is revealed by the analysis. Solely based on the knowledge of interfacial properties of independent surfactant solutions and nanocolloids, the same can be deduced for complex surfactant-based nanocolloids through the proposed approach. The model accurately predicts the equilibrium surface tension and contact angle of complex nanocolloids available in the existing literature and present experimental findings.
International Nuclear Information System (INIS)
Pourtier, E.
2006-11-01
Standard thermodynamic properties (STP) of lanthanides (Ln 3+ ) are necessary to predict their transport in hydrothermal fluids. New STP (apparent molal volumes and heat capacities) of Ln 3+ are determined with dilute (La 3+ , Nd 3+ , Gd 3+ , Yb 3+ ) triflates solutions, up to 300 deg. C and 300 bars, using a vibrating tube flow densimeter and a differential heat flow calorimeter. The triflate anion (CF 3 SO 3 ), stable at high temperature, does not form complexes with Ln 3+ . The STP of HCF 3 SO 3 and NaCF 3 SO 3 are measured in order to get the STP of CF 3 SO 3 . The solubility of the Nd-pure pole of monazite (NdPO 4 ) studied between 300 and 800 deg. C at 2 kbars in H 2 O and H 2 O+NaCl using weight loss and isotope dilution methods, is prograde for neutral pH. The study of Nd 3+ speciation at 650 deg. C and 300 deg. C, 2 kbars, shows that only hydroxylated species are present. These data allow the revision of Ln 3+ parameters in the HKF model. (author)
Gases and carbon in metals - thermodynamics, kinetics, and properties. Pt. 11
International Nuclear Information System (INIS)
Jehn, H.; Speck, H.; Fromm, E.; Hoerz, G.
1980-01-01
This issue is part of a series of data on Gases and Carbon in Metals which supplements the data compilation in the book Gase and Kohlenstoff in Metallen (Gases and Carbon in Metals), edited by E.Fromm and E.Gebhardt, Springer-Verlag, Berlin 1976. The present survey includes results from papers published after the copy deadline and recommends critically selected data. Furthermore it comprises a bibliography of relevant literature. For each element the information is given in two parts. In a first section data are listed and in a second section the relevant literature is compiled. For each element, firstly data on binary systems are presented, starting with hydrogen and followed by carbon, nitrogen, oxygen, and rare gases. Within one metal-metalloid system the data are listed under topics such as solubility, solubility limit, dissociation pressure of compounds, vapour pressure of volatile oxides, thermodynamic data, diffusion, transport parameters (effective valence, heat of transport), permeation of gases through metals, gas absorption and gas desorption kinetics, compound formation kinetics, precipitation kinetics, and property changes. (orig./GE)
Manifestations of Kitaev physics in thermodynamic properties of hexagonal iridates and α-RuCl3
Tsirlin, Alexander
Kitaev model is hard to achieve in real materials. Best candidates available so far are hexagonal iridates M2IrO3 (M = Li and Na) and the recently discovered α-RuCl3 featuring hexagonal layers coupled by weak van der Waals bonding. I will review recent progress in crystal growth of these materials and compare their thermodynamic properties. Both hexagonal iridates and α-RuCl3 feature highly anisotropic Curie-Weiss temperatures that not only differ in magnitude but also change sign depending on the direction of the applied magnetic field. Néel temperatures are largely suppressed compared to the energy scale of the Curie-Weiss temperatures. These experimental observations will be linked to features of the electronic structure and to structural peculiarities associated with deviations from the ideal hexagonal symmetry. I will also discuss how the different nature of ligand atoms affects electronic structure and magnetic superexchange. This work has been done in collaboration with M. Majumder, M. Schmidt, M. Baenitz, F. Freund, and P. Gegenwart.
Determination of thermodynamic properties of aluminum based binary and ternary alloys
Energy Technology Data Exchange (ETDEWEB)
Altıntas, Yemliha [Abdullah Gül University, Faculty of Engineering, Department of Materials Science and Nanotechnology, 38039, Kayseri (Turkey); Aksöz, Sezen [Nevşehir Hacı Bektaş Veli University, Faculty of Arts and Science, Department of Physics, 50300, Nevşehir (Turkey); Keşlioğlu, Kâzım, E-mail: kesli@erciyes.edu.tr [Erciyes University, Faculty of Science, Department of Physics, 38039, Kayseri (Turkey); Maraşlı, Necmettin [Yıldız Technical University, Faculty of Chemical and Metallurgical Engineering, Department of Metallurgical and Materials Engineering, 34210, Davutpaşa, İstanbul (Turkey)
2015-11-15
In the present work, the Gibbs–Thomson coefficient, solid–liquid and solid–solid interfacial energies and grain boundary energy of a solid Al solution in the Al–Cu–Si eutectic system were determined from the observed grain boundary groove shapes by measuring the thermal conductivity of the solid and liquid phases and temperature gradient. Some thermodynamic properties such as the enthalpy of fusion, entropy of fusion, the change of specific heat from liquid to solid and the electrical conductivity of solid phases at their melting temperature were also evaluated by using the measured values of relevant data for Al–Cu, Al–Si, Al–Mg, Al–Ni, Al–Ti, Al–Cu–Ag, Al–Cu–Si binary and ternary alloys. - Highlights: • The microstructure of the Al–Cu–Si eutectic alloy was observed through SEM. • The three eutectic phases (α-Al, Si, CuAl{sub 2}) have been determined by EDX analysis. • Solid–liquid and solid–solid interfacial energies of α-Al solution were determined. • ΔS{sub f},ΔH{sub M}, ΔC{sub P}, electrical conductivity of solid phases for solid Al solutions were determined. • G–T coefficient and grain boundary energy of solid Al solution were determined.
Chaban, Vitaly V.; Andreeva, Nadezhda A.
2017-12-01
Energy generation and storage are at the center of modern civilization. Energetic materials constitute quite a large class of compounds with a high amount of stored chemical energy that can be released. We hereby use a combination of quantum chemistry methods to investigate feasibility and properties of carbon-nitrogen cubanes and multi-charged polynitrogen cations in the context of their synthesis and application as unprecedented energetic materials. We show that the stored energy increases gradually with the nitrogen content increase. Nitrogen-poor cubanes retain their stabilities in vacuum, even at elevated temperatures. Such molecules will be probably synthesized at some point. In turn, polynitrogen cations are highly unstable, except N8H+, despite they are isoelectronic to all-carbon cubane. Kinetic stability of the cation decays drastically as its total charge increases. High-level thermodynamic calculations revealed that large amounts of energy are liberated upon decompositions of polynitrogen cations, which produce molecular nitrogen, acetylene, and protons. The present results bring a substantial insights to the design of novel high-energy compounds.
International Nuclear Information System (INIS)
Green, C.
1979-12-01
A set of FORTRAN subroutines is described for calculating water thermodynamic properties. These were written for use in a transient thermal-hydraulics program, where speed of execution is paramount. The choice of which subroutines to optimise depends on the primary variables in the thermal-hydraulics code. In this particular case the subroutine which has been optimised is the one which calculates pressure and specific enthalpy given the specific volume and the specific internal energy. Another two subroutines are described which complete a self-consistent set. These calculate the specific volume and the temperature given the pressure and the specific enthalpy, and the specific enthalpy and the specific volume given the pressure and the temperature (or the quality). The accuracy is high near the saturation lines, typically less than 1% relative error, and decreases as the fluid becomes more subcooled in the liquid region or more superheated in the steam region. This behaviour is inherent in the method which uses quantities defined on the saturation lines and assumes that certain derivatives are constant for excursions away from these saturation lines. The accuracy and speed of the subroutines are discussed in detail in this report. (author)
Wang, Haiyan; Wang, Weizong; Yan, Joseph D.; Qi, Haiyang; Geng, Jinyue; Wu, Yaowu
2017-10-01
Ablation-controlled plasmas have been used in a range of technical applications where local thermodynamic equilibrium (LTE) is often violated near the wall due to the strong cooling effect caused by the ablation of wall materials. The thermodynamic and transport properties of ablated polytetrafluoroethylene (PTFE) vapor, which determine the flowing plasma behavior in such applications, are calculated based on a two-temperature model at atmospheric pressure. To our knowledge, no data for PTFE have been reported in the literature. The species composition and thermodynamic properties are numerically determined using the two-temperature Saha equation and the Guldberg-Waage equation according to van de Sanden et al’s derivation. The transport coefficients, including viscosity, thermal conductivity and electrical conductivity, are calculated with the most recent collision interaction potentials using Devoto’s electron and heavy-particle decoupling approach but expanded to the third-order approximation (second-order for viscosity) in the frame of the Chapman-Enskog method. Results are computed for different degrees of thermal non-equilibrium, i.e. the ratio of electron to heavy-particle temperatures, from 1 to 10, with electron temperature ranging from 300 to 40 000 K. Plasma transport properties in the LTE state obtained from the present work are compared with existing published results and the causes for the discrepancy analyzed. The two-temperature plasma properties calculated in the present work enable the modeling of wall ablation-controlled plasma processes.
International Nuclear Information System (INIS)
Wang, Haiyan; Qi, Haiyang; Wang, Weizong; Yan, Joseph D; Geng, Jinyue; Wu, Yaowu
2017-01-01
Ablation-controlled plasmas have been used in a range of technical applications where local thermodynamic equilibrium (LTE) is often violated near the wall due to the strong cooling effect caused by the ablation of wall materials. The thermodynamic and transport properties of ablated polytetrafluoroethylene (PTFE) vapor, which determine the flowing plasma behavior in such applications, are calculated based on a two-temperature model at atmospheric pressure. To our knowledge, no data for PTFE have been reported in the literature. The species composition and thermodynamic properties are numerically determined using the two-temperature Saha equation and the Guldberg–Waage equation according to van de Sanden et al ’s derivation. The transport coefficients, including viscosity, thermal conductivity and electrical conductivity, are calculated with the most recent collision interaction potentials using Devoto’s electron and heavy-particle decoupling approach but expanded to the third-order approximation (second-order for viscosity) in the frame of the Chapman–Enskog method. Results are computed for different degrees of thermal non-equilibrium, i.e. the ratio of electron to heavy-particle temperatures, from 1 to 10, with electron temperature ranging from 300 to 40 000 K. Plasma transport properties in the LTE state obtained from the present work are compared with existing published results and the causes for the discrepancy analyzed. The two-temperature plasma properties calculated in the present work enable the modeling of wall ablation-controlled plasma processes. (paper)
Insights into Mercury's Core Evolution from the Thermodynamic Properties of Fe-S-Si
Edgington, A.; Vocadlo, L.; Stixrude, L. P.; Wood, I. G.; Lord, O. T.
2015-12-01
The structure, composition and evolution of Mercury, the innermost planet, are puzzling, as its high uncompressed density implies a body highly enriched in metallic iron, whilst the existence of Mercury's magnetic field and observations of its longitude librations [1] suggest at least a partially molten core. This study uses a combination of experimental and ab-initio computer simulation techniques to determine the properties of Fe-S-Si (relative atomic percentages, 80:10:10) throughout the conditions of the interior of the planet Mercury, and evaluates the implications of this material for the structure and evolution of the planet's core. Previous studies have considered the addition of sulphur to the pure iron system, as this can significantly depress the melting curve of iron, and so may possibly allow Mercury's core to remain molten to the present day [2]. However, important constraints placed by the MESSENGER spacecraft on Mercury's surface abundance of iron [3] suggest that the planet formed in highly reduced conditions, in which significant amounts of silicon could have also dissolved into the core [4]. First-principles molecular dynamics simulations of the thermodynamic properties of liquid Fe-S-Si, alongside laser-heated diamond-anvil-cell experiments to determine the melting behaviour of the same composition, reveal the slopes of the adiabatic gradient and melting curve respectively, which together may allow insight into the evolution of our solar system's smallest planet. [1] Margot, J. L. et al. (2007) Science, 316: 710-714[2] Schubert, G. et al. (1988) in 'Mercury' 429-460[3] Nittler, L. R. et al. (2011) Science, 333, 1847-1850[4] Malavergne, V. et al. (2010) Icarus, 206:199-209
Simulations of the Thermodynamic and Diffusion Properties of Actinide Oxide Fuel Materials
International Nuclear Information System (INIS)
Becker, Udo
2013-01-01
Spent nuclear fuel from commercial reactors is comprised of 95-99 percent UO 2 and 1-5 percent fission products and transuranic elements. Certain actinides and fission products are of particular interest in terms of fuel stability, which affects reprocessing and waste materials. The transuranics found in spent nuclear fuels are Np, Pu, Am, and Cm, some of which have long half- lives (e.g., 2.1 million years for 237 Np). These actinides can be separated and recycled into new fuel matrices, thereby reducing the nuclear waste inventory. Oxides of these actinides are isostructural with UO 2 , and are expected to form solid solutions. This project will use computational techniques to conduct a comprehensive study on thermodynamic properties of actinide-oxide solid solutions. The goals of this project are to: Determine the temperature-dependent mixing properties of actinide-oxide fuels; Validate computational methods by comparing results with experimental results; Expand research scope to complex (ternary and quaternary) mixed actinide oxide fuels. After deriving phase diagrams and the stability of solid solutions as a function of temperature and pressure, the project team will determine whether potential phase separations or ordered phases can actually occur by studying diffusion of cations and the kinetics of potential phase separations or ordered phases. In addition, the team will investigate the diffusion of fission product gases that can also have a significant influence on fuel stability. Once the system has been established for binary solid solutions of Th, U, Np, and Pu oxides, the methodology can be quickly applied to new compositions that apply to ternaries and quaternaries, higher actinides (Am, Cm), burnable poisons (B, Gd, Hf), and fission products (Cs, Sr, Tc) to improve reactivity
International Nuclear Information System (INIS)
Wang Huanyou; Xu Hui; Wang Xianchun; Jiang Chunzhi
2009-01-01
The density function perturbation theory (DFPT) is employed to study the lattice dynamics and thermodynamic properties (with quasiharmonic approximation) of zinc-blende BN. First we discuss the structural properties and compare the phonon spectrum with available Raman scattering experiments. Thereafter using the calculated phonon dispersions we obtain the PTV equation of state from the free energy. Our results for the above properties are generally speaking in good agreement with experiments and with similar theoretical calculations. Owing to the anharmonic effect at high temperature, the calculated linear thermal expansion coefficients (CTE) are low to experimental data.
Macroscopic effects in attosecond pulse generation
International Nuclear Information System (INIS)
Ruchon, T; Varju, K; Mansten, E; Swoboda, M; L'Huillier, A; Hauri, C P; Lopez-Martens, R
2008-01-01
We examine how the generation and propagation of high-order harmonics in a partly ionized gas medium affect their strength and synchronization. The temporal properties of the resulting attosecond pulses generated in long gas targets can be significantly influenced by macroscopic effects, in particular by the intensity in the medium and the degree of ionization which control the dispersion. Under some conditions, the use of gas targets longer than the absorption length can lead to the generation of compressed attosecond pulses. We show these macroscopic effects experimentally, using a 6 mm-long argon-filled gas cell as the generating medium
Macroscopic effects in attosecond pulse generation
Energy Technology Data Exchange (ETDEWEB)
Ruchon, T; Varju, K; Mansten, E; Swoboda, M; L' Huillier, A [Department of Physics, Lund University, PO Box 118, SE-221 00 Lund (Sweden); Hauri, C P; Lopez-Martens, R [Laboratoire d' Optique Appliquee, Ecole Nationale Superieure des Techniques Avancees (ENSTA)-Ecole Polytechnique CNRS UMR 7639, 91761 Palaiseau (France)], E-mail: anne.lhuillier@fysik.lth.se
2008-02-15
We examine how the generation and propagation of high-order harmonics in a partly ionized gas medium affect their strength and synchronization. The temporal properties of the resulting attosecond pulses generated in long gas targets can be significantly influenced by macroscopic effects, in particular by the intensity in the medium and the degree of ionization which control the dispersion. Under some conditions, the use of gas targets longer than the absorption length can lead to the generation of compressed attosecond pulses. We show these macroscopic effects experimentally, using a 6 mm-long argon-filled gas cell as the generating medium.
Czech Academy of Sciences Publication Activity Database
Pátek, Jaroslav; Klomfar, Jaroslav
2006-01-01
Roč. 29, č. 4 (2006), s. 566-578 ISSN 0140-7007 Institutional research plan: CEZ:AV0Z20760514 Keywords : water-lithium bromide * aqueous solution * thermodynamic properties Subject RIV: BJ - Thermodynamics Impact factor: 0.936, year: 2006
Directory of Open Access Journals (Sweden)
B. Hussain
2018-02-01
Full Text Available Mixture phase equilibrium and thermodynamic properties have a significant role in industry. Numerical analysis of flash calculation generates an appropriate solution for the problem. In this research, a comparison of Soave Redlich Kwong (SRK and Peng-Robinson (PR equations of state predicting the thermodynamic properties of a mixture of hydrocarbon and related compounds in a critical region at phase equilibrium is performed. By applying mathematical modeling of both equations of states, the behavior of binary gases mixtures is monitored. The numerical analysis of isothermal flash calculations is applied to study the pressure behavior with volume and mole fraction. The approach used in this research shows considerable convergence with experimental results available in the literature.
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 σ are calculated. In the case of the dipole spectrum, the constants a and σ, 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 σ, 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.
Czech Academy of Sciences Publication Activity Database
Adineh, V.R.; Coufal, O.; Živný, Oldřich
2012-01-01
Roč. 40, č. 10 (2012), s. 2723-2735 ISSN 0093-3813 R&D Projects: GA ČR GAP205/11/2070 Institutional research plan: CEZ:AV0Z20430508 Keywords : Electrical discharge machining * net emission coefficient * nitrogen-iron reaction products * plasma modeling, radiative heat transfer * thermodynamic properties Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 0.868, year: 2012
CSIR Research Space (South Africa)
Fosso-Kankeu, E
2017-04-01
Full Text Available followed the pseudo-second-order rate equation, whereas, the adsorption isotherm followed both the Freundlich and Langmuir isotherm models. The thermodynamics studies revealed that the adsorption processes were spontaneous and endothermic in nature...
Thermodynamic properties of alloys and fusibility diagram of Fe-Ni-Mn system
International Nuclear Information System (INIS)
Danilenko, V.M.; Turkevich, V.Z.
1987-01-01
Thermodynamic calculation of the fusibility diagram of Fe-Ni-Mn system in the subregular solution approximation is performed. The calculated fusibility diagram fits the experimental one in kind and degree
Contact Geometry of Mesoscopic Thermodynamics and Dynamics
Directory of Open Access Journals (Sweden)
Miroslav Grmela
2014-03-01
Full Text Available The time evolution during which macroscopic systems reach thermodynamic equilibrium states proceeds as a continuous sequence of contact structure preserving transformations maximizing the entropy. This viewpoint of mesoscopic thermodynamics and dynamics provides a unified setting for the classical equilibrium and nonequilibrium thermodynamics, kinetic theory, and statistical mechanics. One of the illustrations presented in the paper is a new version of extended nonequilibrium thermodynamics with fluxes as extra state variables.
International Nuclear Information System (INIS)
Koukouvetakis, J.
1988-01-01
The γ-MoC phase with the hexagonal WC structure was prepared without the presence of metal stabilizers at temperatures below 1000 degree C. This phase was found to be thermodynamically stable at low temperatures and decomposed to Mo 2 C and graphite at 1400 K. Using equilibrium and thermodynamic data, the thermodynamic quantities of this phase were calculated. Oxide equilibration and solid-state galvanic cell experiments were used to study thermodynamic properties of binary Lewis acid-base stabilized transition-metal alloys. The activity of vanadium was determined in alloys of vanadium with platinum-group metals such as Rh, Pd, and Ir at 1000 degree C. The activities of titanium in titanium-iridium alloys and of niobium in Nb 3 Ir were determined at 1400 degree C. The ternary phase diagram of V-Pd-O at 1000 degree C was obtained. Based on the vanadium-palladium results, a partial titration curve of palladium by vanadium was constructed. The excess partial molar Gibbs free energy of vanadium at infinite dilution was found to be -36.4 kcal mol -1 at 1000 degree C. Results are in agreement with the predictions of Brewer's theory of transition-metal alloy acid-base behavior
2014-01-01
Background Urease, one of the highly efficient known enzymes, catalyzes the hydrolysis of urea into ammonia and carbon dioxide. The present study aimed to extract urease from pea seeds (Pisum Sativum L). The enzyme was then purified in three consequence steps: acetone precipitation, DEAE-cellulose ion-exchange chromatography, and gel filtration chromatography (Sephacryl S-200 column). Results The purification fold was 12.85 with a yield of 40%. The molecular weight of the isolated urease was estimated by chromatography to be 269,000 Daltons. Maximum urease activity (190 U/g) was achieved at the optimum conditions of 40°C and pH of 7.5 after 5 min of incubation. The kinetic parameters, K m and V max , were estimated by Lineweaver-Burk fits and found to be 500 mM and 333.3 U/g, respectively. The thermodynamic constants of activation, ΔH, E a , and ΔS, were determined using Arrhenius plot and found to be 21.20 kJ/mol, 23.7 kJ/mol, and 1.18 kJ/mol/K, respectively. Conclusions Urease was purified from germinating Pisum Sativum L. seeds. The purification fold, yield, and molecular weight were determined. The effects of pH, concentration of enzyme, temperature, concentration of substrate, and storage period on urease activity were examined. This may provide an insight on the various aspects of the property of the enzyme. The significance of extracting urease from different sources could play a good role in understanding the metabolism of urea in plants. PMID:25065975
Institute of Scientific and Technical Information of China (English)
Ismet KAYA; Cigdem Yigit PALA
2014-01-01
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(tr)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(V0g)was determined for each probe molecule. By using(1/T;lnV0g) graphics,the glass transition temperature of poly( cyclohexyl methacrylate)was found to be 373 K. The adsorp-tion heat under the glass transition temperature(ΔH a ),and partial molar heat of sorption above the glass tran-sition(ΔHS1 ),partial molar free energy of sorption(ΔGS1 )and partial molar entropy of sorption(ΔSS1 )belong-ing to sorption for every probe were calculated. The partial molar heat of mixing at infinite dilution(ΔH∞1 ), partial molar free energy of mixing at infinite dilution(ΔG∞1 ),Flory-Huggins interaction parameter(χ∞12 )and weight fraction activity coefficient(a1/w1)∞ values of polymer-solute systems were calculated at different col-umn temperatures. The solubility parameters(δ2 )of the polymer were obtained by IGC technique.
International Nuclear Information System (INIS)
Soezen, Adnan; Ozalp, Mehmet; Arcaklioglu, Erol
2007-01-01
This study proposes a alternative approach based on artificial neural networks (ANNs) to determine the thermodynamic properties - specific volume, enthalpy and entropy - of an alternative refrigerant (R508b) for both saturated liquid-vapor region (wet vapor) and superheated vapor region. In the ANN, the back-propagation learning algorithm with two different variants, namely scaled conjugate gradient (SCG) and Levenberg-Marquardt (LM), and Logistic Sigmoid transfer function were used to determine the best approach. The most suitable algorithm and with appropriate number of neurons (i.e. 7) in the hidden layer is found to be the LM algorithm which has provided the minimum error. For wet vapor region, R 2 values - which are errors known as absolute fraction of variance - are 0.983495, 0.969027, 0.999984, 0.999963, 0.999981, and 0.999975, for specific volume, enthalpy and entropy for training and testing, respectively. Similarly, for superheated vapor, they are: 0.995346, 0.996947, 0.999996, 0.999997, 0.999974, and 0.999975, for training and testing, respectively. According to the regression analysis results, R 2 values are 0.9312, 0.9708, 0.9428, 0.9343, 0.967 and 0.9546 for specific volume, enthalpy and entropy for wet vapor region and superheated vapor, respectively. The comparisons of the results suggest that, ANN provided results comfortably within the acceptable range. This study, deals with the potential application of the ANNs to represent PVTx (pressure-specific volume-temperature-vapor quality) data. Therefore, reducing the risk of experimental uncertainties and also removing the need for complex analytic equations requiring long computational time and efforts
Martelli, Fausto; Vuilleumier, Rodolphe; Simonin, Jean-Pierre; Spezia, Riccardo
2012-10-01
In this work, we show how increasing the charge of small cations affects the structural, thermodynamical, and dynamical properties of these ions in liquid water. We have studied the case of lanthanoid and actinoid ions, for which we have recently developed accurate polarizable force fields, and the ionic radius is in the 0.995-1.250 Å range, and explored the valency range from 0 to 4+. We found that the ion charge strongly structures the neighboring water molecules and that, in this range of charges, the hydration enthalpies exhibit a quadratic dependence with respect to the charge, in line with the Born model. The diffusion process follows two main regimes: a hydrodynamical regime for neutral or low charges, and a dielectric friction regime for high charges in which the contraction of the ionic radius along the series of elements causes a decrease of the diffusion coefficient. This latter behavior can be qualitatively described by theoretical models, such as the Zwanzig and the solvated ion models. However, these models need be modified in order to obtain agreement with the observed behavior in the full charge range. We have thus modified the solvated ion model by introducing a dependence of the bare ion radius as a function of the ionic charge. Besides agreement between theory and simulation this modification allows one to obtain an empirical unified model. Thus, by analyzing the contributions to the drag coefficient from the viscous and the dielectric terms, we are able to explain the transition from a regime in which the effect of viscosity dominates to one in which dielectric friction governs the motion of ions with radii of ca. 1 Å.
Zhou, Siwen; Zhu, Guanglai; Kang, Xianqu; Li, Qiang; Sha, Maolin; Cui, Zhifeng; Xu, Xinsheng
2018-06-01
Using molecular dynamics simulation, the research obtained the thermodynamic properties and microstructures of the mixture of N-octylpyridinium tetrafluoroborate and acetonitrile, including density, self-diffusion coefficients, excess properties, radial distribution functions (RDFs) and spatial distribution functions (SDFs). Both RDFs and SDFs indicate that the local microstructure of the polar region is different from the nonpolar region with different mole fraction of ionic liquids. Acetonitrile could increase the order of the polar regions. While with acetonitrile increasing, the orderliness of the nonpolar region increases firstly and then decreases. In relatively dilute solution, ionic liquids were dispersed to form small aggregates wrapped by acetonitrile.
Energy Technology Data Exchange (ETDEWEB)
Giorgi, R.; Turtu' , S. [ENEA, Centro Ricerche Casaccia, S. Maria di Galeria, RM (Italy). Dipt. Innovazione; Ascarelli, P. [Consiglio Nazionale delle Ricerche, Montelibretti, RM (Italy). Ist. di Metodologie Inorganiche Avanzate
1999-07-01
In this work the electronic properties and the composition of the three layers (diffusive, catalytic and outermost) are studied separately. In the first part, an anomalous behaviour of the photoemission peaks from the diffusive layer has been evidenced and correlated with the macroscopic electronic conductivity. In the second part, the electronic properties of the PT clusters are compared with the macroscopic electron conductivity. In the second part, the electronic properties of the PT clusters are compared with those of PT bulk, as a function of thermal treatment and after half-cell measurements. A correlation of the binding energy, asymmetry and width of the peaks with the different status of the metal has been attempted. [Italian] Il lavoro consiste di due parti: l'una dedicata allo studio delle caratteristiche dello strato di supporto e diffusivo, l'altra allo studio dello strato catalizzatore. Nella prima parte, la presenza anomala negli spettri XPS viene messa in relazione con la conducibilita' elettronica delle nanoparticelle metalliche in funzione delle condizioni di preparazione degli elettrodi e delle simulazioni di funzionamento. Sono messe in evidenza le problematiche connesse all'interpretazione degli spettri di fotoemissione da sistemi costituiti da particelle nanometriche, intermedi tra la condizione di atomo isolato e quella del solido, in cui gli effetti di dimensione svolgono un ruolo importante nel determinare risposte diverse ed inaspettate rispetto al comportamento del metallo massivo.
Theoretical physics 5 thermodynamics
Nolting, Wolfgang
2017-01-01
This concise textbook offers a clear and comprehensive introduction to thermodynamics, one of the core components of undergraduate physics courses. It follows on naturally from the previous volumes in this series, defining macroscopic variables, such as internal energy, entropy and pressure,together with thermodynamic principles. The first part of the book introduces the laws of thermodynamics and thermodynamic potentials. More complex themes are covered in the second part of the book, which describes phases and phase transitions in depth. Ideally suited to undergraduate students with some grounding in classical mechanics, the book is enhanced throughout with learning features such as boxed inserts and chapter summaries, with key mathematical derivations highlighted to aid understanding. The text is supported by numerous worked examples and end of chapter problem sets. About the Theoretical Physics series Translated from the renowned and highly successful German editions, the eight volumes of this series cove...
Determination of the thermodynamic properties of complexation and extraction by micro-calorimetry
International Nuclear Information System (INIS)
Charbonnel, M.Ch.; Flandin, J.L.
2000-01-01
The CEA is currently developing the DIAMEX process, the first step in the strategy for the separation of minor actinides from high-level radioactive waste. The extractant belongs to the diamide family of molecules and is able to co-extract trivalent actinides and lanthanides. This study focuses on the thermodynamic properties (ΔH, ΔG, ΔS) of lanthanide extraction by malonamide in order to better understand the mechanisms involved and to account for differences in the behavior of various diamide extractants. The main technique used is microcalorimetric titration. The Thermal Activity Monitor (TAM) microcalorimeter is a modular system with a highly stable (± 0.1 mK) temperature-controlled bath containing up to four calorimetry vessel units. The sensor bulbs inserted in the reaction vessel can measure heat flows in static or dynamic conditions. Micro-calorimetry, and calorimetric titration in particular, is a fast growing field due to technical improvements in both hardware and software. In the case of an equilibrium reaction, titration allows both Δ r G and Δ r H (and thus Δ r S) to be determined simultaneously. It was decided to initiate this thermochemical investigation with a homogeneous phase reaction, and the first study concerned the aqueous phase complexation of a trivalent lanthanide ion by a water-soluble diamide, tetraethyl-malonamide (TEMA: (C 2 H 5 ) 2 NCO-CH 2 CON(C 2 H 5 ) 2 ). In the test system, the heat of dilution of the diamide in water is preponderant over the heat arising from the complexation reaction; the result is a positive value corresponding to an endothermic reaction. However, the equilibration constant K and Δ H are both very small, and cannot be calculated from the resulting Q v f(n TEMA ) curves. Moreover, in aqueous phase, the reactions involved are different from those observed when neodymium(III) is extracted into an organic phase, and the medium must be further characterized before the calorimetry data can be fully
Ha, Vu Thi Thanh; Hung, Vu Van; Hanh, Pham Thi Minh; Tuyen, Nguyen Viet; Hai, Tran Thi; Hieu, Ho Khac
2018-03-01
The thermodynamic and mechanical properties of III-V zinc-blende AlP, InP semiconductors and their alloys have been studied in detail from statistical moment method taking into account the anharmonicity effects of the lattice vibrations. The nearest neighbor distance, thermal expansion coefficient, bulk moduli, specific heats at the constant volume and constant pressure of the zincblende AlP, InP and AlyIn1-yP alloys are calculated as functions of the temperature. The statistical moment method calculations are performed by using the many-body Stillinger-Weber potential. The concentration dependences of the thermodynamic quantities of zinc-blende AlyIn1-yP crystals have also been discussed and compared with those of the experimental results. Our results are reasonable agreement with earlier density functional theory calculations and can provide useful qualitative information for future experiments. The moment method then can be developed extensively for studying the atomistic structure and thermodynamic properties of nanoscale materials as well.
International Nuclear Information System (INIS)
Bhatt, Darshak; Maheria, Kalpana; Parikh, Jigisha
2014-01-01
Highlights: • Interaction of ionic liquid and ethylene oxide based non-ionic surfactants in aqueous media. • Evaluation of various surface properties and thermodynamic parameters. • Micellar growth ensues from exothermic to endothermic with increase in temperature. • Micelle formation is enthalpy driven at low temperature and entropy driven at higher temperature. • The micellization power and adsorption proficiency decreased at high IL concentrations. - Abstract: The mixed system of ionic liquid (IL) tetraethyl ammonium tetrafluoroborate [TEA(BF 4 )] and numerous ethylene oxide based non-ionic surfactants in aqueous media were studied using surface tension, viscosity and dynamic light scattering (DLS) measurements. Various surface properties like critical micelle concentration (cmc), maximum surface excess concentration (Γ max ), minimum surface area per surfactant molecule (A min ), surface tension at the cmc (γ cmc ), adsorption efficiency (pC 20 ), and effectiveness of surface tension reduction (π cmc ) as well as thermodynamic parameters of micellization have been determined. DLS and viscosity measurements revealed that the micellar growth was attributed to the bridged solvophilicity of the POE chain in surfactants at elevated temperatures. In most of the cases, the progression ensues from exothermic to endothermic with increase in temperature of the mixed system. Thermodynamic parameter indicates that the micelle formation process is enthalpy driven at low temperature and entropy driven at higher temperature
International Nuclear Information System (INIS)
Asta, M.; Foiles, S.M.; Quong, A.A.
1998-01-01
The configurational thermodynamic properties of fcc-based Al-Sc alloys and coherent Al/Al 3 Sc interphase-boundary interfaces have been calculated from first principles. The computational approach used in this study combines the results of pseudopotential total-energy calculations with a cluster-expansion description of the alloy energetics. Bulk and interface configurational-thermodynamic properties are computed using a low-temperature-expansion technique. Calculated values of the {100} and {111} Al/Al 3 Sc interfacial energies at zero temperature are, respectively, 192 and 226mJ/m 2 . The temperature dependence of the calculated interfacial free energies is found to be very weak for {100} and more appreciable for {111} orientations; the primary effect of configurational disordering at finite temperature is to reduce the degree of crystallographic anisotropy associated with calculated interfacial free energies. The first-principles-computed solid-solubility limits for Sc in bulk fcc Al are found to be underestimated significantly in comparison with experimental measurements. It is argued that this discrepancy can be largely attributed to nonconfigurational contributions to the entropy which have been neglected in the present thermodynamic calculations. copyright 1998 The American Physical Society
Thermodynamic properties by Equation of state of liquid sodium under pressure
Li, Huaming; Sun, Yongli; Zhang, Xiaoxiao; Li, Mo
Isothermal bulk modulus, molar volume and speed of sound of molten sodium are calculated through an equation of state of a power law form within good precision as compared with the experimental data. The calculated internal energy data show the minimum along the isothermal lines as the previous result but with slightly larger values. The calculated values of isobaric heat capacity show the unexpected minimum in the isothermal compression. The temperature and pressure derivative of various thermodynamic quantities in liquid Sodium are derived. It is discussed about the contribution from entropy to the temperature and pressure derivative of isothermal bulk modulus. The expressions for acoustical parameter and nonlinearity parameter are obtained based on thermodynamic relations from the equation of state. Both parameters for liquid Sodium are calculated under high pressure along the isothermal lines by using the available thermodynamic data and numeric derivations. By comparison with the results from experimental measurements and quasi-thermodynamic theory, the calculated values are found to be very close at melting point at ambient condition. Furthermore, several other thermodynamic quantities are also presented. Scientific Research Starting Foundation from Taiyuan university of Technology, Shanxi Provincial government (``100-talents program''), China Scholarship Council and National Natural Science Foundation of China (NSFC) under Grant No. 11204200.
International Nuclear Information System (INIS)
Jayaganthan, R.; Hajra, J.P.
1997-01-01
Interaction parameter formalism is considered to be important for representation of the excess thermodynamic properties of multi-component systems. In the present article, the same method as adopted in their earlier article has been used for deducing the partials of the Quatenary System. The derivation of lnγ 1 , lnγ 2 , lnγ 3 and lnγ 4 of the quaternary system involves extensive summation of various infinite series pertaining to first order and quaternary parameters in order to preserve thermodynamic consistency. Although the derivation and consistency of the partials are described elsewhere, a brief outline of the latter with an emphasis of their applicability to the experimental data of the Fe-Ni-Ta-N system in the temperature range of 1,796--1,983K are presented
Sologubov, S. S.; Markin, A. V.; Smirnova, N. N.; Novozhilova, N. A.; Tatarinova, E. A.; Muzafarov, A. M.
2018-02-01
The heat capacity of a first-generation carbosilane dendrimer with terminal phenylethyl groups as a function of temperature in the range from 6 to 520 K is studied for the first time via precision adiabatic vacuum calorimetry and differential scanning calorimetry. Physical transformations, such as low-temperature structural anomaly and glass transition are detected in the above-mentioned range of temperatures, and their standard thermodynamic characteristics are determined and analyzed. The standard thermodynamic functions of the studied dendrimer in the range of T → 0 to 520 K are calculated from the experimental data, as is the standard entropy in the devitrified state at T = 298.15 K. The standard thermodynamic characteristics of the carbosilane dendrimers studied in this work and earlier are compared.
Energy Technology Data Exchange (ETDEWEB)
Wang, Yuezhong, E-mail: wyzphysics@163.com [Department of Physics and Key Laboratory for Radiation Physics and Technology of Ministry of Education, Sichuan University, Chengdu 610064 (China); Tianjin Jinhang Institute of Technical Physics, Tianjin 300192 (China); Lu, Tiecheng, E-mail: lutiecheng@scu.edu.cn [Department of Physics and Key Laboratory for Radiation Physics and Technology of Ministry of Education, Sichuan University, Chengdu 610064 (China); International Center for Material Physics, Chinese Academy of Sciences, Shenyang 110015 (China); Zhang, Rongshi [Tianjin Jinhang Institute of Technical Physics, Tianjin 300192 (China); Jiang, Shengli; Qi, Jianqi; Wang, Ying [Department of Physics and Key Laboratory for Radiation Physics and Technology of Ministry of Education, Sichuan University, Chengdu 610064 (China); Chen, Qingyun [Department of Physics and Key Laboratory for Radiation Physics and Technology of Ministry of Education, Sichuan University, Chengdu 610064 (China); National Defense Key Discipline Laboratory of Nuclear Waste and Environmental Safety, Southwest University of Science and Technology, Mianyang 621010 (China); Miao, Naihua [Physique Theorique des Materiaux, Universite de Liege, Sart Tilman B-4000 (Belgium); He, Duanwei [Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610064 (China)
2013-01-25
Highlights: Black-Right-Pointing-Pointer We reassess the chemical bonding character of {gamma}-AlON which shows strong ionicity. Black-Right-Pointing-Pointer {gamma}-AlON single-crystals exhibit highly elastic anisotropy. Black-Right-Pointing-Pointer The thermodynamic properties are investigated in a wider temperature/pressure range. Black-Right-Pointing-Pointer {gamma}-AlON is an O/N partially disordered structure. - Abstract: Spinel aluminium oxynitride ({gamma}-AlON), as a kind of transparent ceramic material expectable, is studied using the ab initio density functional method, in terms of electronic, elastic, thermodynamic properties and structure disorder. The results show that {gamma}-AlON exhibits strong ionicity, as quantitatively expressed by (Al{sub O}{sup 2.43+}){sub 15}(Al{sub T}{sup 2.41+}){sub 8}(O{sup 1.64-}){sub 27}(N{sup 2.27-}){sub 5} from our reassessment of the ionic character. We summarize and speculate that the considered oxynitride single-crystals exhibit highly elastic anisotropy. The interpretation of the thermodynamic properties of {gamma}-AlON according to quasi-harmonic Debye model confirm the available experiments and are extended to a wider temperature/pressure range. This material holds high elastic strength under extreme environments, where dB/dT absolute value is less than 0.03 GPa/K, independent of the pressure. Finally, we study the O/N structure disorder character of {gamma}-AlON solid solution by investigating nine possible crystal structures. It is found that {gamma}-AlON should be partially disordered, and in fact, the O/N ordering has a significant effect on the properties.
International Nuclear Information System (INIS)
Wang, Yuezhong; Lu, Tiecheng; Zhang, Rongshi; Jiang, Shengli; Qi, Jianqi; Wang, Ying; Chen, Qingyun; Miao, Naihua; He, Duanwei
2013-01-01
Highlights: ► We reassess the chemical bonding character of γ-AlON which shows strong ionicity. ► γ-AlON single-crystals exhibit highly elastic anisotropy. ► The thermodynamic properties are investigated in a wider temperature/pressure range. ► γ-AlON is an O/N partially disordered structure. - Abstract: Spinel aluminium oxynitride (γ-AlON), as a kind of transparent ceramic material expectable, is studied using the ab initio density functional method, in terms of electronic, elastic, thermodynamic properties and structure disorder. The results show that γ-AlON exhibits strong ionicity, as quantitatively expressed by (Al O 2.43+ ) 15 (Al T 2.41+ ) 8 (O 1.64- ) 27 (N 2.27- ) 5 from our reassessment of the ionic character. We summarize and speculate that the considered oxynitride single-crystals exhibit highly elastic anisotropy. The interpretation of the thermodynamic properties of γ-AlON according to quasi-harmonic Debye model confirm the available experiments and are extended to a wider temperature/pressure range. This material holds high elastic strength under extreme environments, where dB/dT absolute value is less than 0.03 GPa/K, independent of the pressure. Finally, we study the O/N structure disorder character of γ-AlON solid solution by investigating nine possible crystal structures. It is found that γ-AlON should be partially disordered, and in fact, the O/N ordering has a significant effect on the properties.
Mechanical, Thermodynamic and Electronic Properties of Wurtzite and Zinc-Blende GaN Crystals
Luan, Xinghe; Feng, Chuang; Yang, Daoguo; Zhang, Guoqi
2017-01-01
For the limitation of experimental methods in crystal characterization, in this study, the mechanical, thermodynamic and electronic properties of wurtzite and zinc-blende GaN crystals were investigated by first-principles calculations based on density functional theory. Firstly, bulk moduli, shear moduli, elastic moduli and Poisson’s ratios of the two GaN polycrystals were calculated using Voigt and Hill approximations, and the results show wurtzite GaN has larger shear and elastic moduli and exhibits more obvious brittleness. Moreover, both wurtzite and zinc-blende GaN monocrystals present obvious mechanical anisotropic behavior. For wurtzite GaN monocrystal, the maximum and minimum elastic moduli are located at orientations [001] and , respectively, while they are in the orientations and for zinc-blende GaN monocrystal, respectively. Compared to the elastic modulus, the shear moduli of the two GaN monocrystals have completely opposite direction dependences. However, different from elastic and shear moduli, the bulk moduli of the two monocrystals are nearly isotropic, especially for the zinc-blende GaN. Besides, in the wurtzite GaN, Poisson’s ratios at the planes containing [001] axis are anisotropic, and the maximum value is 0.31 which is located at the directions vertical to [001] axis. For zinc-blende GaN, Poisson’s ratios at planes (100) and (111) are isotropic, while the Poisson’s ratio at plane (110) exhibits dramatically anisotropic phenomenon. Additionally, the calculated Debye temperatures of wurtzite and zinc-blende GaN are 641.8 and 620.2 K, respectively. At 300 K, the calculated heat capacities of wurtzite and zinc-blende are 33.6 and 33.5 J mol−1 K−1, respectively. Finally, the band gap is located at the G point for the two crystals, and the band gaps of wurtzite and zinc-blende GaN are 3.62 eV and 3.06 eV, respectively. At the G point, the lowest energy of conduction band in the wurtzite GaN is larger, resulting in a wider band gap
Mechanical, Thermodynamic and Electronic Properties of Wurtzite and Zinc-Blende GaN Crystals
Directory of Open Access Journals (Sweden)
Hongbo Qin
2017-12-01
Full Text Available For the limitation of experimental methods in crystal characterization, in this study, the mechanical, thermodynamic and electronic properties of wurtzite and zinc-blende GaN crystals were investigated by first-principles calculations based on density functional theory. Firstly, bulk moduli, shear moduli, elastic moduli and Poisson’s ratios of the two GaN polycrystals were calculated using Voigt and Hill approximations, and the results show wurtzite GaN has larger shear and elastic moduli and exhibits more obvious brittleness. Moreover, both wurtzite and zinc-blende GaN monocrystals present obvious mechanical anisotropic behavior. For wurtzite GaN monocrystal, the maximum and minimum elastic moduli are located at orientations [001] and <111>, respectively, while they are in the orientations <111> and <100> for zinc-blende GaN monocrystal, respectively. Compared to the elastic modulus, the shear moduli of the two GaN monocrystals have completely opposite direction dependences. However, different from elastic and shear moduli, the bulk moduli of the two monocrystals are nearly isotropic, especially for the zinc-blende GaN. Besides, in the wurtzite GaN, Poisson’s ratios at the planes containing [001] axis are anisotropic, and the maximum value is 0.31 which is located at the directions vertical to [001] axis. For zinc-blende GaN, Poisson’s ratios at planes (100 and (111 are isotropic, while the Poisson’s ratio at plane (110 exhibits dramatically anisotropic phenomenon. Additionally, the calculated Debye temperatures of wurtzite and zinc-blende GaN are 641.8 and 620.2 K, respectively. At 300 K, the calculated heat capacities of wurtzite and zinc-blende are 33.6 and 33.5 J mol−1 K−1, respectively. Finally, the band gap is located at the G point for the two crystals, and the band gaps of wurtzite and zinc-blende GaN are 3.62 eV and 3.06 eV, respectively. At the G point, the lowest energy of conduction band in the wurtzite GaN is larger
Mechanical, Thermodynamic and Electronic Properties of Wurtzite and Zinc-Blende GaN Crystals.
Qin, Hongbo; Luan, Xinghe; Feng, Chuang; Yang, Daoguo; Zhang, Guoqi
2017-12-12
For the limitation of experimental methods in crystal characterization, in this study, the mechanical, thermodynamic and electronic properties of wurtzite and zinc-blende GaN crystals were investigated by first-principles calculations based on density functional theory. Firstly, bulk moduli, shear moduli, elastic moduli and Poisson's ratios of the two GaN polycrystals were calculated using Voigt and Hill approximations, and the results show wurtzite GaN has larger shear and elastic moduli and exhibits more obvious brittleness. Moreover, both wurtzite and zinc-blende GaN monocrystals present obvious mechanical anisotropic behavior. For wurtzite GaN monocrystal, the maximum and minimum elastic moduli are located at orientations [001] and , respectively, while they are in the orientations and for zinc-blende GaN monocrystal, respectively. Compared to the elastic modulus, the shear moduli of the two GaN monocrystals have completely opposite direction dependences. However, different from elastic and shear moduli, the bulk moduli of the two monocrystals are nearly isotropic, especially for the zinc-blende GaN. Besides, in the wurtzite GaN, Poisson's ratios at the planes containing [001] axis are anisotropic, and the maximum value is 0.31 which is located at the directions vertical to [001] axis. For zinc-blende GaN, Poisson's ratios at planes (100) and (111) are isotropic, while the Poisson's ratio at plane (110) exhibits dramatically anisotropic phenomenon. Additionally, the calculated Debye temperatures of wurtzite and zinc-blende GaN are 641.8 and 620.2 K, respectively. At 300 K, the calculated heat capacities of wurtzite and zinc-blende are 33.6 and 33.5 J mol -1 K -1 , respectively. Finally, the band gap is located at the G point for the two crystals, and the band gaps of wurtzite and zinc-blende GaN are 3.62 eV and 3.06 eV, respectively. At the G point, the lowest energy of conduction band in the wurtzite GaN is larger, resulting in a wider band gap. Densities of
International Nuclear Information System (INIS)
Xiong, Yongliang
2007-01-01
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) 2 (brucite)-based engineered barrier. The chemical function of the engineered barrier is to consume CO 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 5 (CO 3 ) 4 (OH) 2 · 4H 2 O). As MgO is in excess relative to CO 2 that may be produced, the brucite-hydromagnesite (5424) assemblage would buffer f 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 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 Δ f G brucite 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 -1 (Konigsberger et al., 1999; Geochim. Cosmochim. Acta, 3105-3119). Using the Δ f G hydromagnesite (5424) 0 from Konigsberger et al., the predicted log f CO2 for this assemblage would range from -5.96 (Δ f G brucite 0 from Harvie et al.) to -4.84 (Δ f G brucite 0 from Konigsberger et al.). Therefore, it is desirable to better constrain the Δ f G brucite 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 Δ f G brucite 0 from this study by extrapolation to infinite dilution via Pitzer formalism is -830.8 kJ mol -1 , which is in excellent agreement with
Microscopic and macroscopic bell inequalities
International Nuclear Information System (INIS)
Santos, E.
1984-01-01
The Bell inequalities, being derived for micro-systems, cannot be tested by (macroscopic) experiments without additional assumptions. A macroscopic definition of local realism is proposed which might be the starting point for deriving Bell inequalities testable without auxiliary assumptions. (orig.)
Eichhorn, Ralf; Aurell, Erik
2014-04-01
'Stochastic thermodynamics as a conceptual framework combines the stochastic energetics approach introduced a decade ago by Sekimoto [1] with the idea that entropy can consistently be assigned to a single fluctuating trajectory [2]'. This quote, taken from Udo Seifert's [3] 2008 review, nicely summarizes the basic ideas behind stochastic thermodynamics: for small systems, driven by external forces and in contact with a heat bath at a well-defined temperature, stochastic energetics [4] defines the exchanged work and heat along a single fluctuating trajectory and connects them to changes in the internal (system) energy by an energy balance analogous to the first law of thermodynamics. Additionally, providing a consistent definition of trajectory-wise entropy production gives rise to second-law-like relations and forms the basis for a 'stochastic thermodynamics' along individual fluctuating trajectories. In order to construct meaningful concepts of work, heat and entropy production for single trajectories, their definitions are based on the stochastic equations of motion modeling the physical system of interest. Because of this, they are valid even for systems that are prevented from equilibrating with the thermal environment by external driving forces (or other sources of non-equilibrium). In that way, the central notions of equilibrium thermodynamics, such as heat, work and entropy, are consistently extended to the non-equilibrium realm. In the (non-equilibrium) ensemble, the trajectory-wise quantities acquire distributions. General statements derived within stochastic thermodynamics typically refer to properties of these distributions, and are valid in the non-equilibrium regime even beyond the linear response. The extension of statistical mechanics and of exact thermodynamic statements to the non-equilibrium realm has been discussed from the early days of statistical mechanics more than 100 years ago. This debate culminated in the development of linear response
Thermodynamic properties of citric acid and the system citric acid-water
Kruif, C.G. de; Miltenburg, J.C. van; Sprenkels, A.J.J.; Stevens, G.; Graaf, W. de; Wit, H.G.M. de
1982-01-01
The binary system citric acid-water has been investigated with static vapour pressure measurements, adiabatic calorimetry, solution calorimetry, solubility measurements and powder X-ray measurements. The data are correlated by thermodynamics and a large part of the phase diagram is given. Molar heat
Correlation of water vapor adsorption behavior of wood with surface thermodynamic properties
Mandla A. Tshabalala; Agnes R. Denes; R. Sam. Williams
1999-01-01
To improve the overall performance of wood-plastic composites, appropriate technologies are needed to control moisture sorption and to improve the interaction of wood fiber with selected hydrophobic matrices. The objective of this study was to determine the surface thermodynamic characteristics of a wood fiber and to correlate those characteristics with the fiberas...
Assessment of the thermodynamic properties and phase diagram of the Bi-Pd system
Czech Academy of Sciences Publication Activity Database
Vřešťál, Jan; Pinkas, J.; Watson, A.; Scott, A.; Houserová, Jana; Kroupa, Aleš
2006-01-01
Roč. 30, č. 1 (2006), s. 14-17 ISSN 0364-5916 R&D Projects: GA MŠk OC 531.001; GA MŠk OC 531.002 Institutional research plan: CEZ:AV0Z20410507 Keywords : phase diagram * ab initio calculations * calorimetry Subject RIV: BJ - Thermodynamics Impact factor: 1.432, year: 2006
Thermodynamic properties of titanates, zirconates and hafnates of alkaline earth metals
Energy Technology Data Exchange (ETDEWEB)
1978-02-01
The problems are considered arising in critical analysis and choosing recommended values of thermodynamic constants of the series of the most important perovskites-ferroelectrics-titanates, zirconates, and hafnates of alkaline-earth metals finding application in modern radioelectronics. Recommended values of standard thermodynamic values are given: heat capacity Csub(p,298) , enthalpy change H/sub 298/-H/sub 0/, entropy S/sub 298/, heat formation ..delta..Hsub(f,298 ), free energy formation ..delta..Gsub(f,298) , temperatures and heats of phase transitions with indication of errors for the adopted values. The effect of impurities on thermal constants of phase transitions is discussed. The relationships between thermodynamic characteristics of perovskites and crystal structure as well as the effect of orthorhombic distortions of ideal perovskite lattice on entropy of the compounds have been considered. Along with thermodynamic methods of investigation, a great attention is given to other physical methods which have been used for finding temperature regions of phase transitions, Curie points, and temperatures of transition from ferroelectric to paraelectric state. The importance of physical methods is emphasized in those cases when phase transitions are accompanied by small energy changes and are not fixed in measuring heat capacity.
Thermodynamic and mechanical properties of curved interfaces : a discussion of models
Oversteegen, M.
2000-01-01
Although relatively much is known about the physics of curved interfaces, several models for these kind of systems seem conflicting or internally inconsistent. It is the aim of this thesis to derive a rigorous framework of thermodynamic and mechanical expressions and study their relation to
Thermodynamic properties of molten mixtures of lithium, rubidium, cesium and beryllium chlorides
International Nuclear Information System (INIS)
Zarubitskij, O.G.; Podafa, B.P.; Dubovoj, P.G.
1982-01-01
e. m. f. in binary systems of beryllium chloride with rubidium and cesium chlorides were measured. Concentration dependences of thermodynamic functions (mixing entropy Gibbs free energy) of beryllium chloride in the systems as well as with the participation of lithium chloride were analysed
Assessment of thermodynamic properties and phase diagram in the Ag–In–Pd system
Czech Academy of Sciences Publication Activity Database
Zemanová, A.; Semenova, O.; Kroupa, Aleš; Vřešťál, J.; Chandrasekaran, K.; Richter, K. W.; Ipser, H.
2007-01-01
Roč. 15, č. 1 (2007), s. 77-84 ISSN 0966-9795 R&D Projects: GA MŠk(CZ) OC 532.001 Institutional research plan: CEZ:AV0Z20410507 Keywords : phase diagrams * ternary alloy systems * prediction Subject RIV: BJ - Thermodynamics Impact factor: 2.219, year: 2007