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Sample records for aqueous thermodynamic properties

  1. Excess Thermodynamic Properties of Concentrated Aqueous Solutions at High Temperatures

    International Nuclear Information System (INIS)

    Measurements of the vapor pressure of the solvent in wide ranges of concentration and temperature provide information on solute solvation and ion pairing--the two phenomena most often invoked for description of dilute solutions. Even in moderately concentrated solutions, as interionic distances become comparable to ionic diameters, these simple concepts gradually lose their meaning and solutions behave like molten salts. The usefulness of experimental vapor pressure results increases rapidly with their accuracy, since derived properties, such as solution enthalpies and heat capacities, can be calculated. Very accurate results can be obtained by the isopiestic method, but primary vapor pressure data for standard solutions are needed. In order to obtain vapor pressures at conditions where accurate isopiestic standards are not available and to establish more accurate standards, the ORNL isopiestic apparatus was modified for simultaneous direct vapor pressure measurements and isopiestic comparisons. There are no comprehensive solution theories derived from molecular level models and able to predict thermodynamic properties of various electrolytes as the composition changes from dilute solutions to molten salts in a wide range of temperatures. Empirical and semi-empirical models are useful for representation of experimental results, interpretation of measurements of other properties such as conductance., solubility or liquid-vapor partitioning of solutes, and for verification of theoretical predictions. Vapor pressures for aqueous CaCl(sub 2), CaBr(sub 2), LiCl, LiBr, LiI, NaI were measured at temperatures between 380 and 523 K in the concentration range extended to water activities below 0.2 (over 30 mol/kg for LiCl). General equations based on the modified Pitzer ion-interaction model were used to obtain enthalpy and heat capacity surfaces, which are compared with direct calorimetric measurements

  2. Effects of hydration on the thermodynamic properties of aqueous ethylene glycol ether solutions

    Energy Technology Data Exchange (ETDEWEB)

    Schroedle, Simon [Institut fuer Physikalische und Theoretische Chemie, Universitaet Regensburg, D-93040 Regensburg (Germany); Hefter, Glenn [Chemistry Department, DSE Murdoch University, Murdoch, WA 6150 (Australia); Buchner, Richard [Institut fuer Physikalische und Theoretische Chemie, Universitaet Regensburg, D-93040 Regensburg (Germany)]. E-mail: richard.buchner@chemie.uni-regensburg.de

    2005-05-15

    The densities and isobaric specific heat capacities of binary mixtures of water with various open-chain and cyclic ethylene glycol ethers have been measured at 298.15 K using vibrating tube densimetry, and flow or differential scanning calorimetry, respectively. Excess molar volumes were derived over the whole composition range. Molar isobaric heat capacities and the relative apparent thermodynamic quantities were determined in the water-rich region. The data reflect the changes in the structure and hydrogen-bond dynamics of water caused by these non-ionic solutes. The observed effects are discussed in terms of the influence of hydrophobic hydration on the thermodynamic properties of aqueous solutions. Correlations are given that enable the prediction of the thermodynamic properties of open-chain and cyclic oligo(ethylene oxide) ethers in their pure liquid state and at infinite dilution in water.

  3. Effects of hydration on the thermodynamic properties of aqueous ethylene glycol ether solutions

    International Nuclear Information System (INIS)

    The densities and isobaric specific heat capacities of binary mixtures of water with various open-chain and cyclic ethylene glycol ethers have been measured at 298.15 K using vibrating tube densimetry, and flow or differential scanning calorimetry, respectively. Excess molar volumes were derived over the whole composition range. Molar isobaric heat capacities and the relative apparent thermodynamic quantities were determined in the water-rich region. The data reflect the changes in the structure and hydrogen-bond dynamics of water caused by these non-ionic solutes. The observed effects are discussed in terms of the influence of hydrophobic hydration on the thermodynamic properties of aqueous solutions. Correlations are given that enable the prediction of the thermodynamic properties of open-chain and cyclic oligo(ethylene oxide) ethers in their pure liquid state and at infinite dilution in water

  4. Forecasting of thermodynamic properties of solution for non-polar molecules in aqueous salt solutions and in aqueous organic solutions

    International Nuclear Information System (INIS)

    The scaled particle theory has been used rather successfully to predict the values of thermodynamic properties of solution for non-polar molecules. Two very important parameters has been used in the equations of the scaled particle theory: the hard sphere diameter of the solute and the closeness of the solvent (closeness in which the diameters of the hard sphere particles forming the solvent are taken into account). With non-polar solutes, a correlation exists between calculated and experimental values of: free enthalpy of solution - enthalpy of solution - molar heat capacity change for the solution process. The fit between calculated and experimental values is only more qualitative than quantitative. However the variation of thermodynamic properties with the temperature and the modality is consistent with the variation calculated according to the scaled particle theory. (author)

  5. Mixed system of ionic liquid and non-ionic surfactants in aqueous media: Surface and thermodynamic properties

    International Nuclear Information System (INIS)

    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(BF4)] 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 (Γmax), minimum surface area per surfactant molecule (Amin), surface tension at the cmc (γcmc), adsorption efficiency (pC20), and effectiveness of surface tension reduction (πcmc) 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

  6. Equilibrium partial pressures, thermodynamic properties of aqueous and solid phases, and Cl{sub 2} production from aqueous HCl and HNO{sub 3} and their mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Massucci, M.; Clegg, S.L.; Brimblecombe, P. [Univ. of East Anglia, Norwich (United Kingdom). School of Environmental Sciences

    1999-05-27

    Equilibrium total pressures have been measured above aqueous HNO{sub 3} and aqueous HCl using a capacitance manometer. Equilibrium partial pressures of the acids have also been determined, by mass spectrometry, from 274.8 to 234.6 K for both HCl solutions, and from 265.0 to 240.1 K for 15.73 mol kg{sup {minus}1} HNO{sub 3}. Results are generally consistent with model predictions, though with small systematic deviations for the total pressure measurements over aqueous HCl at about 220 K. Mixtures of HCl{minus}HNO{sub 3}{minus}H{sub 2}O composition yielded measured total pressures orders of magnitude greater than predicted for the gases H{sub 2}O, HNO{sub 3}, and HCl. Mass spectrometric determinations and equilibrium thermodynamic calculations suggest that Cl{sub 2} and NOCl were produced by the reaction: 4H{sup +}{sub aq} + NO{sub 3}{sup {minus}}{sub aq} + 3Cl{sup {minus}}{sub aq} {r_equilibrium} NOCl{sub aq} + Cl{sub 2(aq)} + 2H{sub 2}O{sub (1)}, which is known to occur in aqua regia. Calculations for aqueous solutions of stratospheric aerosol composition suggest, purely on equilibrium grounds, that the reaction could be a source of active chlorine in the stratosphere. The correlation of Clegg and Brimblecombe of the thermodynamic properties of aqueous HNO{sub 3} activities has been revised, and vapor pressure products assessed from literature studies. The activity product for the reaction HNO{sub 3}{center_dot}2H{sub 2}O{sub (cr)} {r_equilibrium} H{sup +}{sub (aq)} + NO{sub 3}{sup {minus}}{sub (aq)} + 2H{sub 2}O{sub (1)} has also been determined. The model of Carslaw et al. has been revised for the solubility of HBr in aqueous H{sub 2}SO{sub 4} to stratospheric temperatures.

  7. Thermodynamic and transport properties of some biologically active compounds in aqueous solutions at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Dhondge, Sudhakar S., E-mail: s_dhondge@hotmail.co [P.G. Department of Chemistry, S.K. Porwal College, Kamptee, Nagpur 441 002 (India); Zodape, Sangesh P.; Parwate, Dilip V. [Department of Chemistry, R.T.M. Nagpur University, Nagpur 440 033 (India)

    2011-01-15

    The experimental data of density and viscosity have been obtained for aqueous solutions of biologically active compounds like salbutamol sulphate (SS), diethylcarbamazine citrate (DEC), and chlorpheniramine maleate (CPM) in the concentration range (0 to 0.15) mol . kg{sup -1} at three different temperatures. The derived parameters, such as apparent molar volume of solute ({phi}{sub V})), limiting apparent molar volume of solute ({phi}{sub V}{sup 0}), limiting apparent molar expansivity ({phi}{sub E}{sup 0}), thermal expansion coefficient ({alpha}*) and Jones-Dole equation viscosity A and B coefficients, were obtained using the density and viscosity results. It has been observed that the electrolyte-salt (SS) as well as adducts exhibit a positive viscosity B coefficient having negative ((dB)/(dT)). These results are interpreted in the light of possible solute-solute and solute-solvent interactions.

  8. Thermodynamic and transport properties of some biologically active compounds in aqueous solutions at different temperatures

    International Nuclear Information System (INIS)

    The experimental data of density and viscosity have been obtained for aqueous solutions of biologically active compounds like salbutamol sulphate (SS), diethylcarbamazine citrate (DEC), and chlorpheniramine maleate (CPM) in the concentration range (0 to 0.15) mol . kg-1 at three different temperatures. The derived parameters, such as apparent molar volume of solute (φV)), limiting apparent molar volume of solute (φV0), limiting apparent molar expansivity (φE0), thermal expansion coefficient (α*) and Jones-Dole equation viscosity A and B coefficients, were obtained using the density and viscosity results. It has been observed that the electrolyte-salt (SS) as well as adducts exhibit a positive viscosity B coefficient having negative ((dB)/(dT) ). These results are interpreted in the light of possible solute-solute and solute-solvent interactions.

  9. Effect of alkyl chain length and temperature on the thermodynamic properties of ionic liquids 1-alkyl-3-methylimidazolium bromide in aqueous and non-aqueous solutions at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Sadeghi, Rahmat [Department of Chemistry, University of Kurdistan, Sanandaj (Iran, Islamic Republic of)], E-mail: rahsadeghi@yahoo.com; Shekaari, Hemayat [Department of Chemistry, Faculty of Science, University of Mohaghegh Ardabili, Ardabil (Iran, Islamic Republic of); Hosseini, Rahim [Department of Chemistry, University of Kurdistan, Sanandaj (Iran, Islamic Republic of)

    2009-02-15

    The alkyl chain length of 1-alkyl-3-methylimidazolium bromide ([Rmim][Br], R = propyl (C{sub 3}), hexyl (C{sub 6}), heptyl (C{sub 7}), and octyl (C{sub 8})) was varied to prepare a series of room-temperature ionic liquids (RTILs), and experimental measurements of density and speed of sound at different temperatures ranging from (288.15 to 308.15) K for their aqueous and methanolic solutions in the dilute concentration region (0.01 to 0.30) mol . kg{sup -1} were taken. The values of the compressibilities, expansivity and apparent molar properties for [C{sub n}mim][Br] in aqueous and methanolic solutions were determined at the investigated temperatures. The obtained apparent molar volumes and apparent molar isentropic compressibilities were fitted to the Redlich-Mayer and the Pitzer's equations from which the corresponding infinite dilution molar properties were obtained. The values of the infinite dilution molar properties were used to obtain some information about solute-solvent and solute-solute interactions. The thermodynamic properties of investigated ionic liquids in aqueous solutions have been compared with those in methanolic solutions. Also, the comparison between thermodynamic properties of investigated solutions and those of electrolyte solutions, polymer solutions, cationic surfactant solutions and tetraalkylammonium salt solutions have been made.

  10. Thermodynamic properties of aqueous-alcoholic solutions of sodium chloride. H2O-2-C3H7OH-NaCl

    Science.gov (United States)

    Veryaeva, E. S.; Konstantinova, N. M.; Mamontov, M. N.; Uspenskaya, I. A.

    2010-11-01

    The temperature-concentration dependences of the NaCl activity coefficient in aqueous solutions of isopropanol (propanol-2) at temperatures of 298.15 and 323.15 K (solution ionic force, 0.01 to 3 m; alcohol content, 10-60 wt %) were determined through the electromotive force method with an ion-selective electrode. A Pitzer model was used to mathematically describe the thermodynamic properties. The integral Gibbs energy of the solution formation of the H2O-2-C3H7OH-NaCl ternary system was performed according to Darken's method. The dissociation degree of salt in the investigated solutions was estimated using the literature data on the association constant of NaCl in aqueous-isopropanol solution.

  11. Thermodynamics of micellization of alkylimidazolium surfactants in aqueous solution

    International Nuclear Information System (INIS)

    Alkylimidazolium salts are a very important class of compounds. So far, calorimetry has hardly been used to characterize their solution behaviour. The enthalpies obtained from indirect methods have an intrinsic large uncertainty, and nowadays it is clear that calorimetry is the most sensitive technique for directly measuring the thermodynamic properties of aggregation. In this work, isothermal titration calorimetry (ITC) was used along with conductivity to determine the thermodynamics of aggregation of 1-alkyl-3-methylimidazolium chlorides ([Cnmim]Cl, n = 8, 10, 12, and 14) in aqueous solution. The critical micelle concentrations, cmc, were obtained from conductivity and calorimetry, and the enthalpies of micelle formation, ΔHmic, were derived from the calorimetric titrations. From conductivity, we could also derive the values for the degree of ionisation of the micelles (α), the molar conductivity (ΛM) of the [Cnmim]Cl micellar species and the molar conductivity at infinite dilution (Λ∞) for the [Cnmim]+ cations. Values are therefore reported for the enthalpy (ΔHmic), the Gibbs free energy (ΔGmic) and entropy (ΔSmic) changes for micelle formation. Further, the aggregate sizes and aggregation numbers were obtained by light scattering (LS) measurements. The observed variation of the thermodynamic properties with the alkyl chain length is discussed in detail and compared with the traditional cationic surfactants 1-alkyl-trimethylammonium chlorides, [CnTA]Cl. The difference in the values of the thermodynamic parameters for both types of surfactants is here related to the structure of their head groups

  12. Ab-initio assessment of conventional standard-state thermodynamic properties of geochemically relevant gaseous and aqueous species

    Science.gov (United States)

    Vetuschi Zuccolini, M.; Ottonello, G.; Belmonte, D.

    2011-05-01

    After some introductory remarks on the essential basic concepts concerning isolated (gas state) atoms and molecules (adiabatic vs. vertical ionization potential and electron affinity; dissociation energy), we will show how their (absolute) internal energy and enthalpy (i.e. "thermal corrections" to the energy of the molecule) may be converted into the conventional counterparts of common use in thermochemistry through an appropriate thermochemical cycle. The first-principles acceptation of entropy, in terms of translational, rotational, vibrational, and electronic contributions to the bulk partition function, will then be briefly restated, emphasizing that, for practical calculations, the V-dependency of the translational terms can be converted into a P-dependency with the perfect gas law. The entropy of "aqueous" species will then be discussed after some preliminary remarks on the significance of the "solvation entropy" in terms of a Polarized Continuum Model (PCM) conceptual framework, and some comments on the energy of the "hydronium ion" H 3O +. Some comments on the nature of the electrostatic portion of the solvation entropy, in terms of the Born solvation theory, and the non-electrostatic portion (solvent collapse+cavity formation+dispersion+repulsion+liberation entropy terms), will then be made, showing how this last term may be computed practically by exploiting its analogy with the Helgeson-Kirkham-Flowers electrostatic approach. After some elementary application of the various concepts to the gaseous state, we will present a potential application of major use in geochemistry, i.e. the possibility of computing ab-initio the interaction parameters (i.e. individual activity coefficients) of complex ions in solution through PCM procedures. We will then discuss the state of the art attained in determining ab-initio the p Ka scale of organic and inorganic acids, perhaps the most demanding task, due to the high level of internal precision required. Finally, we

  13. Thermodynamic modeling of hydrogen sulfide absorption by aqueous N-methyldiethanolamine using the Extended UNIQUAC model

    DEFF Research Database (Denmark)

    Sadegh, Negar; Stenby, Erling Halfdan; Thomsen, Kaj

    2015-01-01

    Aqueous MDEA is the most commonly used solvent for H2S removal from natural gas. A reliable thermodynamic model is required for the proper design of natural gas sweetening processes. In this study, a rigorous thermodynamic model is developed to represent properties of the H2S-MDEA-H2O ternary...

  14. Surface tension and related thermodynamic quantities of aqueous electrolyte solutions

    CERN Document Server

    Matubayasi, Norihiro

    2013-01-01

    Surface tension provides a thermodynamic avenue for analyzing systems in equilibrium and formulating phenomenological explanations for the behavior of constituent molecules in the surface region. While there are extensive experimental observations and established ideas regarding desorption of ions from the surfaces of aqueous salt solutions, a more successful discussion of the theory has recently emerged, which allows the quantitative calculation of the distribution of ions in the surface region. Surface Tension and Related Thermodynamic Quantities of Aqueous Electrolyte Solutions provides a d

  15. A suite of programs, OptimA, OptimB, OptimC, and OptimS compatible with the Unitherm database, for deriving the thermodynamic properties of aqueous species from solubility, potentiometry and spectroscopy measurements

    International Nuclear Information System (INIS)

    Highlights: • Programs for deriving thermodynamic parameters of aqueous species are described. • OptimA finds G0(T, P) of species from results of chemical measurements. • OptimS finds G0(T, P) of species by processing UV–Vis absorption spectra. • OptimB finds HKF parameters of a species using its G0(T, P) values. • OptimC finds Ryzhenko–Bryzgalin parameters of a species using its pKdis(T, P). - Abstract: This paper describes four programs for Windows, designed to obtain the thermodynamic properties of aqueous species from experimental data and reporting them in the Unitherm database format (HCh software package). Programs OptimA and OptimS allow users to derive the standard Gibbs free energies of aqueous species from the results of chemical experiments (e.g., potentiometry or solubility) and from ultraviolet–visible (UV–Vis) absorption spectra, respectively; programs OptimB and OptimC enable optimization of the parameters of the revised Helgeson–Kirkham–Flowers equation of state and the modified Ryzhenko–Bryzgalin electrostatic model, respectively, for an aqueous species from its standard Gibbs free energy or stability constant as a function of temperature and pressure

  16. A comparison study between sodium dodecyl sulfate and sodium dodecyl sulfonate with respect to the thermodynamic properties, micellization, and interaction with poly(ethylene glycol) in aqueous solutions

    International Nuclear Information System (INIS)

    Graphical abstract: Apparent molar volume against molality: o, ·, and Δ, respectively in water, (1 and 4) wt% PEG solution at 293.15 K; x, Δ, and lozenge, respectively in water, (1 and 4) wt% PEG solution at 313.15 K. Research highlights: → C12H25SO3Na(SDSn) was seen to interact with PEG more weakly than C12H25SO4Na(SDS). → The constraints on molecular mobility of SDS micelles are larger than those of SDSn. → Entropy change on micellization for SDSn is larger than those for SDS. → Micelle formation of SDS is less endothermic and more spontaneous than that of SDSn. → Micelles of SDS have smaller aggregation number than that of SDSn. - Abstract: The density, sound velocity, and conductivity measurements were performed on aqueous solutions of sodium dodecyl sulfate (C12H25SO4Na) or sodium dodecyl sulfonate (C12H25SO3Na) in the absence and presence of poly(ethylene glycol) (PEG) at different temperatures. Changes in the apparent molar volumes and isentropic compressibilities upon micellization were derived using a pseudophase-transition approach and the infinite dilution apparent molar properties of the monomer and micellar form of C12H25SO4Na and C12H25SO3Na were determined. Variations of the critical micelle concentrations (CMCs) of both surfactants in the solutions investigated with temperature were obtained from which thermodynamic parameters of micellization were estimated. It was found that at low temperature the micelle formation process is endothermic and therefore, this process must be entropically driven. However, upon increasing the temperature, the enthalpic factor becomes more significant and, at temperatures higher than 303.15 K the micellization is enthalpy driven. The interactions between C12H25SO4Na/C12H25SO3Na and PEG were studied and it was found that sodium alkyl sulfonates were seen to interact more weakly than their sulfate analogues.

  17. A comparison study between sodium dodecyl sulfate and sodium dodecyl sulfonate with respect to the thermodynamic properties, micellization, and interaction with poly(ethylene glycol) in aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Sadeghi, Rahmat, E-mail: rsadeghi@uok.ac.ir [Department of Chemistry, University of Kurdistan, Sanandaj (Iran, Islamic Republic of); Shahabi, Somayyeh [Department of Chemistry, University of Kurdistan, Sanandaj (Iran, Islamic Republic of)

    2011-09-15

    Graphical abstract: Apparent molar volume against molality: o, {center_dot}, and {Delta}, respectively in water, (1 and 4) wt% PEG solution at 293.15 K; x, {Delta}, and lozenge, respectively in water, (1 and 4) wt% PEG solution at 313.15 K. Research Highlights: > C{sub 12}H{sub 25}SO{sub 3}Na(SDSn) was seen to interact with PEG more weakly than C{sub 12}H{sub 25}SO{sub 4}Na(SDS). > The constraints on molecular mobility of SDS micelles are larger than those of SDSn. > Entropy change on micellization for SDSn is larger than those for SDS. > Micelle formation of SDS is less endothermic and more spontaneous than that of SDSn. > Micelles of SDS have smaller aggregation number than that of SDSn. - Abstract: The density, sound velocity, and conductivity measurements were performed on aqueous solutions of sodium dodecyl sulfate (C{sub 12}H{sub 25}SO{sub 4}Na) or sodium dodecyl sulfonate (C{sub 12}H{sub 25}SO{sub 3}Na) in the absence and presence of poly(ethylene glycol) (PEG) at different temperatures. Changes in the apparent molar volumes and isentropic compressibilities upon micellization were derived using a pseudophase-transition approach and the infinite dilution apparent molar properties of the monomer and micellar form of C{sub 12}H{sub 25}SO{sub 4}Na and C{sub 12}H{sub 25}SO{sub 3}Na were determined. Variations of the critical micelle concentrations (CMCs) of both surfactants in the solutions investigated with temperature were obtained from which thermodynamic parameters of micellization were estimated. It was found that at low temperature the micelle formation process is endothermic and therefore, this process must be entropically driven. However, upon increasing the temperature, the enthalpic factor becomes more significant and, at temperatures higher than 303.15 K the micellization is enthalpy driven. The interactions between C{sub 12}H{sub 25}SO{sub 4}Na/C{sub 12}H{sub 25}SO{sub 3}Na and PEG were studied and it was found that sodium alkyl sulfonates were seen

  18. The Thermodynamic Properties of Cubanite

    Science.gov (United States)

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

    2012-01-01

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

  19. Interfacial Thermodynamics of Coexisting Aqueous Polymer Solutions

    NARCIS (Netherlands)

    Vis, M.

    2015-01-01

    Phase separation is commonly observed when two different polymers are present in aqueous solution, forming aqueous two-phase systems which typically consist for 90% of water. It is demonstrated that the presence of charge on one of the polymers results in an electric potential difference between the

  20. Calculation of the Aqueous Thermodynamic Properties of Citric Acid Cycle Intermediates and Precursors and the Estimation of High Temperature and Pressure Equation of State Parameters

    OpenAIRE

    Mitchell Schulte; Peter Dalla-Betta

    2009-01-01

    The citric acid cycle (CAC) is the central pathway of energy transfer for many organisms, and understanding the origin of this pathway may provide insight into the origins of metabolism. In order to assess the thermodynamics of this key pathway for microorganisms that inhabit a wide variety of environments, especially those found in high temperature environments, we have calculated the properties and parameters for the revised Helgeson-Kirkham-Flowers equation of state for the major component...

  1. Interfacial Thermodynamics of Coexisting Aqueous Polymer Solutions

    OpenAIRE

    Vis, M

    2015-01-01

    Phase separation is commonly observed when two different polymers are present in aqueous solution, forming aqueous two-phase systems which typically consist for 90% of water. It is demonstrated that the presence of charge on one of the polymers results in an electric potential difference between the two phases. Upon phase separation, the polyelectrolyte is confined in majority to one of the phases. Although small ions can equilibrate freely between the phases, the restriction of macroscopic c...

  2. Thermodynamic properties of cerium oxide

    International Nuclear Information System (INIS)

    Thermodynamic properties of cerium oxides in the CeO2-CeO1.5 composition range are studied. For this purpose method of electromotive force with solid electrolyte is used, equilibrium constants of reduction of cerium oxides by hydrogen are measured. Necessity of using atmosphere of argon or purified nitrogen to work with pyrophoric cerium oxides is stressed. The obtained results and the earlier known literary data on CeO2 and Ce2O3 thermodynamic properties are tabulated. 14 refs.; 5 tabs

  3. Thermodynamics of dilute aqueous solutions of imidazolium based ionic liquids

    International Nuclear Information System (INIS)

    Research highlights: → The thermodynamic behaviour of aqueous imidazolium ILs has been investigated. → Volumetric and ultrasonic results indicated the hydrophobic hydration of ILs. → Viscometric studies revealed studied ionic liquids as water-structure makers. → Hydration number increased with increase in alkyl chain length of the cation. - Abstract: Experimental measurements of density ρ, speed of sound u, and viscosity η of aqueous solutions of various 1-alkyl-3-methylimidazolium based ionic liquid (IL) solutions have been performed in dilute concentration regime at 298.15 K to get insight into hydration behaviour of ILs. The investigated ILs are based on 1-alkyl-3-methylimidazolium cation, [Cnmim] having [BF4]-, [Cl]-, [C1OSO3]-, and [C8OSO3]- as anions where n = 4 or 8. Several thermodynamic parameters like apparent molar volume φV, isentropic compressibility βs, and viscosity B-coefficients have been derived from experimental data. Limiting value of apparent molar volume has been discussed in terms of intrinsic molar volume (Vint) molar electrostriction volume (Velec), molar disordered (Vdis), and cage volume (Vcage). Viscosity B-coefficients have been used to quantify the kosmotropic or chaotropic nature of ILs. Hydration number of ILs obtained using elctrostriction volume, isentropic compressibility, viscosity, and differential scanning calorimetry have been found to be comparative within the experimental error. The hydrophobic hydration has found to play an important role in hydration of ILs as compared to hydration due to hydrogen bonding and electrostriction. Limiting molar properties, hydration numbers, and B-coefficients have been discussed in terms of alkyl chain length of cation or nature of anion.

  4. Calculation of the Aqueous Thermodynamic Properties of Citric Acid Cycle Intermediates and Precursors and the Estimation of High Temperature and Pressure Equation of State Parameters

    Directory of Open Access Journals (Sweden)

    Mitchell Schulte

    2009-06-01

    Full Text Available The citric acid cycle (CAC is the central pathway of energy transfer for many organisms, and understanding the origin of this pathway may provide insight into the origins of metabolism. In order to assess the thermodynamics of this key pathway for microorganisms that inhabit a wide variety of environments, especially those found in high temperature environments, we have calculated the properties and parameters for the revised Helgeson-Kirkham-Flowers equation of state for the major components of the CAC. While a significant amount of data is not available for many of the constituents of this fundamental pathway, methods exist that allow estimation of these missing data.

  5. Thermodynamic properties of Alkali Halides

    International Nuclear Information System (INIS)

    The method of moments of [1], developed by the authors in [2] for strongly and harmonic crystals with f.c.c. structure is used here to investigate the main thermodynamic properties of the potassium halides. Their analytic expressions as functions of temperature are obtained and the comparison between the theoretical results and the experimental data is made. (author). 22 refs., 5 tabs

  6. Group additivity calculation of the standard molal thermodynamic properties of aqueous amino acids, polypeptides and unfolded proteins as a function of temperature, pressure and ionization state

    Directory of Open Access Journals (Sweden)

    J. M. Dick

    2005-10-01

    Full Text Available Thermodynamic calculation of the chemical speciation of proteins and the limits of protein metastability affords a quantitative understanding of the biogeochemical constraints on the distribution of proteins within and among different organisms and chemical environments. These calculations depend on accurate determination of the ionization states and standard molal Gibbs free energies of proteins as a function of temperature and pressure, which are not generally available. Hence, to aid predictions of the standard molal thermodynamic properties of ionized proteins as a function of temperature and pressure, calculated values are given below of the standard molal thermodynamic properties at 25°C and 1 bar and the revised Helgeson-Kirkham-Flowers equations of state parameters of the structural groups comprising amino acids, polypeptides and unfolded proteins. Group additivity and correlation algorithms were used to calculate contributions by ionized and neutral sidechain and backbone groups to the standard molal Gibbs free energy (Δ G°, enthalpy (Δ H°, entropy (S°, isobaric heat capacity (C°P, volume (V° and isothermal compressibility (κ°T of multiple reference model compounds. Experimental values of C°P, V° and κ°T at high temperature were taken from the recent literature, which ensures an internally consistent revision of the thermodynamic properties and equations of state parameters of the sidechain and backbone groups of proteins, as well as organic groups. As a result, Δ G°, Δ H°, S° C°P, V° and κ°T of unfolded proteins in any ionization state can be calculated up to T~-300°C and P~-5000 bars. In addition, the ionization states of unfolded proteins as a function of not only pH, but also temperature and pressure can be calculated by taking account of the degree of ionization of the sidechain and backbone groups present in the sequence. Calculations of this

  7. Thermodynamic Properties of Supported Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Gorte, Raymond J.

    2014-03-26

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

  8. Thermodynamics of aqueous sodium dodecyl sulfate

    Energy Technology Data Exchange (ETDEWEB)

    Berg, R.L.

    1977-08-01

    A flow microcalorimeter system was assembled and is being used in a thermodynamic study of surfactant systems as part of the ERDA enhanced oil recovery program. Enthalpies of dilution and demicellization of sodium dodecyl sulfate were measured over a temperature range of 20 to 35/sup 0/C. This surfactant was also studied with cosurfactant and salt backgrounds. The critical micelle concentrations (cmc) were determined and are in excellent agreement with those in the literature. Studies below the cmc suggest the possible formation of a dimer. 17 tables, 9 figures.

  9. 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...

  10. 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.

  11. Thermodynamic properties of uranium dioxide

    International Nuclear Information System (INIS)

    In order to provide reliable and consistent data on the thermophysical properties of reactor materials for reactor safety studies, this revision is prepared for the thermodynamic properties of the uranium dioxide portion of the fuel property section of the report Properties for LMFBR Safety Analysis. Since the original report was issued in 1976, there has been international agreement on a vapor pressure equation for the total pressure over UO2, new methods have been suggested for the calculation of enthalpy and heat capacity, and a phase change at 2670 K has been proposed. In this report, an electronic term is used in place of the Frenkel defect term in the enthalpy and heat capacity equation and the phase transition is accepted

  12. Thermodynamic Properties of Dimethyl Carbonatea)

    Science.gov (United States)

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

    2011-12-01

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

  13. Thermodynamic properties of modified gravity theories

    Science.gov (United States)

    Bamba, Kazuharu

    2016-06-01

    We review thermodynamic properties of modified gravity theories, such as F(R) gravity and f(T) gravity, where R is the scalar curvature and T is the torsion scalar in teleparallelism. In particular, we explore the equivalence between the equations of motion for modified gravity theories and the Clausius relation in thermodynamics. In addition, thermodynamics of the cosmological apparent horizon is investigated in f(T) gravity. We show both equilibrium and nonequilibrium descriptions of thermodynamics. It is demonstrated that the second law of thermodynamics in the universe can be met, when the temperature of the outside of the apparent horizon is equivalent to that of the inside of it.

  14. Infinite dilution partial molar properties of aqueous solutions of nonelectrolytes. I. Equations for partial molar volumes at infinite dilution and standard thermodynamic functions of hydration of volatile nonelectrolytes over wide ranges of conditions

    Science.gov (United States)

    Plyasunov, Andrey V.; O'Connell, John P.; Wood, Robert H.

    2000-02-01

    A semitheoretical expression for partial molar volumes at infinite dilution of aqueous nonelectrolyte solutes has been developed employing the collection of properties from fluctuation solution theory for use over wide ranges of temperature and pressure. The form of the solution expression was suggested by a comparison of solute/solvent and solvent/solvent direct correlation function integrals (DCFI). The selection of solvent density and compressibility as model variables provides a correct description in the critical region while second virial coefficients have been used to give a rigorous expression in the low density region. The formulation has been integrated to obtain analytic expressions for thermodynamic properties of hydration at supercritical temperatures. The equation is limited to solutes for which B12 (the second cross virial coefficient between water and a solute molecule) is known or can be estimated. Regression of the three remaining parameters gives good correlations of the available experimental data. A strategy for estimating these parameters allows prediction from readily available data.

  15. Influence of alkyl chain on the thermodynamic properties of aqueous solutions of ionic liquids 1-alkyl-3-methylimidazolium bromide at different temperatures

    International Nuclear Information System (INIS)

    Osmotic coefficients φ, mean activity coefficients γ±, vapor pressure p data, and excess Gibbs free energies GE of aqueous solutions of three ionic liquids 1-propyl-3-methylimidazolium bromide [PMIm]Br, 1-pentyl-3-methylimidazolium bromide [PnMIm]Br, and 1-hexyl-3-methylimidazolium bromide [HMIm]Br were determined by the vapor pressure osmometry method at four temperatures (298.15 K to 328.15 K) in intervals 10 K. From the comparison of osmotic coefficients it follows that aqueous solution of [PMIm]Br shows a more pronounced deviation from Debye-Hueckel limiting law (DHLL) and vapor pressure depression more than the other studied ionic liquids which was interpreted in terms of hydrophobic interactions. The Pitzer-ion interaction and MNRTL electrolyte models satisfactorily correlate experimental osmotic coefficient data with good precision. The parameters of the Pitzer-ion interaction model are used to calculate the mean molal activity coefficients and excess Gibbs free energies

  16. Effect of sodium phosphate salts on the thermodynamic properties of aqueous solutions of poly(ethylene oxide) 6000 at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Sadeghi, Rahmat [Department of Chemistry, University of Kurdistan, Sanandaj (Iran, Islamic Republic of)], E-mail: rahsadeghi@yahoo.com; Hosseini, Rahim; Jamehbozorg, Bahman [Department of Chemistry, University of Kurdistan, Sanandaj (Iran, Islamic Republic of)

    2008-09-15

    Precise density, sound velocity, water activity, and phase diagram measurements have been carried out on polyethylene oxide (PEO) in aqueous solutions of sodium di-hydrogen phosphate, di-sodium hydrogen phosphate, and tri-sodium phosphate over a range of temperatures at atmospheric pressure. The experimental density and sound velocity data are used to calculate the apparent specific volume and isentropic compressibility as a function of temperature and concentration. It was found that both of the apparent specific volume and isentropic compressibility of PEO in aqueous solutions increase by increasing temperature and charge on the anion of electrolytes. The results show that the slope of constant water activity lines increased with increasing the temperature and charge on the anion of electrolytes and the vapour pressure depression for an aqueous (PEO + sodium phosphate) system is more than the sum of those for the corresponding binary solutions. Furthermore, the effect of temperature and type of anion of salt on the salting-out effect of polyethylene oxide by sodium phosphate salts has been studied.

  17. Thermodynamic properties of liquid metals

    International Nuclear Information System (INIS)

    The ability of the model potentials to yield accurate thermodynamic properties of liquid metals is tested. The pressure and bulk moduli calculated by the homogeneous deformation (HD) method depend on the electron density derivative of the self energy. The latter is determined predominantly by the choice and specification of the bare ion form factor for q>2ksub(F). Most of the empirical model potentials in the literature have been tested to give good description only in the region 02ksub(F) and are not tested to give good description in this range. Therefore no meaningful calculation of the pressure and bulk moduli of liquid metals could be made at present by the HD method. The long wavelength (LW) method of calculating the bulk moduli involve only the pair potential, which is determined mainly by the choice and specification of the bare ion form factor in the region 0<=q<=2ksub(F). Therefore the LW method can give quantitative results for the compressibility. For Na and K, pair potentials calculated from Shaw's full non-local, energy dependent pseudo-potentials with the inclusion of appropriate effective masses and depletion hole charges is found to give remarkably good results for volume independent properties such as the packing fraction, entropy, constant volume specific heat, the long wavelength of the structure factor and the bulk modulus calculated by the LW method. The Ashcroft model potential is the best of all available local model potentials, but being a local one parameter potential can give only semi quantitative results for cohesive energy and bulk modulus calculated by the LW method. (author)

  18. Thermodynamic properties of standard seawater

    Directory of Open Access Journals (Sweden)

    J. Safarov

    2009-04-01

    Full Text Available (p, ρ, T data of standard seawater with practical salinity S≈35 (corresponding to an absolute salinity SA≈35.16504 g/kg measured at T=(273.14 to 468.06 K and pressures up to p=140 MPa are reported with an estimated experimental relative combined standard uncertainty of 0.006% in density. The measurements were made with a newly constructed vibration-tube densimeter. The system was calibrated using double-distilled water, methanol and aqueous NaCl solutions. An empirical correlation for the density of standard seawater has been developed as a function of pressure and temperature. This equation of state was used to calculate other volumetric properties such as isothermal compressibility, isobaric thermal expansibility, differences in isobaric and isochoric heat capacities, thermal pressure coefficient, internal pressure and secant bulk modulus. The results can be used to extend the present equation of state of seawater to higher temperature as a function of pressure.

  19. Synthesis and Properties of Fe3O4-Activated Carbon Magnetic Nanoparticles for Removal of Aniline from Aqueous Solution: Equilibrium, Kinetic and Thermodynamic Studies

    Directory of Open Access Journals (Sweden)

    Babak Kakavandi

    2013-02-01

    Full Text Available In this study, powder activated carbon (PAC and magnetic nanoparticles of iron (III oxide were used for synthesis of Fe3O4-activated carbon magnetic nanoparticles (AC-Fe3O4 MNPs as an adsorbent for the removal of aniline. The characteristics of adsorbent were evaluated by SEM, TEM, XRD and BET. Also, the impact of different parameters such as pH, contact time, adsorbent dosage, aniline initials concentration and solution temperature were studied. The experimental data investigated by Langmuir and Freundlich adsorption isotherms and two models kinetically of pseudo first-order and pseudo second-order. The results indicated that the adsorption followed Langmuir and pseudo second-order models with correlation r2 > 0.98 and r2 > 0.99, respectively. The equilibrium time was obtained after 5 h. According to Langmuir model, the maximum adsorption capacity was 90.91 mg/g at pH = 6, and 20°C. The thermodynamic parameters indicated that adsorption of aniline on magnetic activated carbon was exothermic and spontaneous. This synthesized AC-Fe3O4 MNPs due to have advantages such as easy and rapid separation from solution could be applied as an adsorbent effective for removal of pollutants such as aniline from water and wastewater

  20. Nanofluidics thermodynamic and transport properties

    CERN Document Server

    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...

  1. Thermodynamic properties of uranyl metaborate

    International Nuclear Information System (INIS)

    The standard enthalpy of formation of crystalline UO2(BO2)2 (-2542.5 ± 3.5 kJ/mol) at 298.15 K was determined by reaction calorimetry. The heat capacity of this compound was measured over the temperature range 6-302 K by adiabatic vacuum calorimetry. The thermodynamic functions were calculated, including the standard entropy (502.8 ± 2.1 J/(mol K)) and Gibbs function of formation (-2392.5 ± 4.0 kJ/mol) at 298.15 K. The standard thermodynamic functions of reactions with the participation of uranyl metaborate were calculated and analyzed

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

    Science.gov (United States)

    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.

  3. Thermodynamic properties of modified gravity theories

    CERN Document Server

    Bamba, Kazuharu

    2016-01-01

    We review thermodynamic properties of modified gravity theories such as $F(R)$ gravity and $f(T)$ gravity, where $R$ is the scalar curvature and $T$ is the torsion scalar in teleparallelism. In particular, we explore the equivalence between the equations of motion for modified gravity theories and the Clausius relation in thermodynamics. In addition, thermodynamics of the cosmological apparent horizon is investigated in $f(T)$ gravity. We show both equilibrium and non-equilibrium descriptions of thermodynamics. It is demonstrated that the second law of thermodynamics in the universe can be met when the temperature of the outside of the apparent horizon is equivalent to that of the inside of it.

  4. Industrial Requirements for Thermodynamics and Transport Properties

    DEFF Research Database (Denmark)

    Hendriks, Eric; Kontogeorgis, Georgios; Dohrn, Ralf;

    2010-01-01

    This work reports the results of an investigation on industrial requirements for thermodynamic and transport properties carried out by the Working Party on Thermodynamic and Transport properties (http://www.wp-ttp.dk/) of the European Federation of Chemical Engineering, EFCE (http...... collaboration. The main results are as follows. There is (still) an acute need for accurate, reliable, and thermodynamically consistent experimental data. Quality is more important than quantity. Similarly, there is a great need for reliable predictive, rather than correlative, models covering a wide range of...... compositions, temperatures, and pressures and capable of predicting primary (phase equilibrium) and secondary (enthalpy, heat capacity, etc.) properties. It is clear that the ideal of a single model covering all requirements is not achievable, but there is a consensus that this ideal should still provide the...

  5. Prediction of Thermodynamic Properties for Halogenated Hydrocarbon

    Science.gov (United States)

    Higashi, Yukihiro

    The predictive methods of thermodynamic properties are discussed with respect to the halogenated hydrocarbons using as working fluids for refrigeration and heat pump cycles. The methods introduced into this paper can be calculated by the limited information; critical properties, normal boiling point and acentric factor. The results of prediction are compared with the experimental values of PVT property, vapor pressure and saturated liquid density. On the basis of these comparisons, Lydersen's method for predicting the critical properties, the generalized vapor pressure correlation by Ashizawa et, al., and Hankinson-Thomson's method for predicting saturated liquid density can be recommended. With respect to the equation of state, either Soave equation or Peng-Robinson equation is effective in calculating the thermodynamic properties except high density region.

  6. Thermodynamic properties of organic compounds estimation methods, principles and practice

    CERN Document Server

    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

  7. Thermodynamic Properties of Hexavalent Uranium Compounds

    International Nuclear Information System (INIS)

    Hexavalent uranium compounds are of importance as starting materials and as intermediary compounds in the preparation of compounds of nuclear interest. Recent experimental work on the thermodynamic and thermal properties, including phase diagrams, of a number of these compounds is presented and discussed in relation to practical applications. Thermodynamic data are given on the systems UO3-U3O8 and UO2 (NO3)2-H2O, based on calorimetric measurements as well as on vapour pressure measurements. Finally, data of some other materials, including the hydrates of uranium peroxide and UO2Cl2, are discussed. Although many of the thermodynamic data are consistent, a number of inconsistencies still remain to be resolved. On this basis suggestions are given for future work. (author)

  8. Consistent thermodynamic properties of lipids systems

    DEFF Research Database (Denmark)

    Cunico, Larissa; Ceriani, Roberta; Sarup, Bent;

    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. To...... 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...... 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...

  9. Obtaining and thermodynamic properties of lithium hydrofluoride

    International Nuclear Information System (INIS)

    Present article is devoted to obtaining and thermodynamic properties of lithium hydrofluoride. Thus, the conditions of obtaining lithium hydrofluoride by interaction of concentrated solutions of hydrofluoric acid and lithium carbonate are defined. The enthalpy of above mentioned reaction by means of solution calorimetry method is defined as well. On the basis of experimental and reference data the enthalpy value of lithium hydrofluoride formation is evaluated. (author)

  10. Study of thermodynamic properties of aqueous binary mixtures of glycine, L-alanine and β-alanine at low temperatures (T = 275.15, 279.15, and 283.15) K

    International Nuclear Information System (INIS)

    Highlights: ► Study of aqueous solutions of amino acids at low temperatures is presented. ► Amino acids are biologically important compounds. ► Different interactions among solute and solvents have been investigated. ► Hydrogen bonding plays pivotal role in these systems. - Abstract: In the present communication, experimental values of density (ρ) and speed of sound (u) of aqueous solutions of three amino acids, namely glycine, L-alanine and β-alanine at different temperatures i.e.T = (275.15, 279.15, and 283.15) K are reported. From the experimental values, different derived parameters such as apparent molar volume of solute (φV), isentropic compressibility of solution (βS), apparent molar isentropic compressibility of solute (φKS) have been calculated. The limiting values of apparent molar volume of solute (φV0), apparent molar isentropic compressibility of solute (φKS0) and apparent molar expansivity (φE0) in the aqueous medium have also been obtained. The temperature coefficients of these limiting properties have also been computed. The results obtained were interpreted in terms of solute–solvent and solute–solute interactions, and structure making and structure breaking abilities of the solute in aqueous medium.

  11. Ideal Gas thermodynamic properties of simple alkanols

    International Nuclear Information System (INIS)

    The ideal gas thermodynamic properties (C /SUP o/ /SUB p/ , S /SUP o/ (T)-S0(O) and H /SUP o/ (T)-H /SUP o/ (0)) of methanol (CH3OH), ethanol (C2H5OH), 1-propanol (CH3CH2CH2OH), and 2-propanol ((CH3)2CHOH) over the temperature range 0 to 1500 K at 1.01325-bar (1-atm) pressure are calculated by the statistical mechanical method, employing the recent molecular and spectroscopic constants. The internal rotational contributions to the thermodynamic properties caused by the presence of -CH3,-C2H5, and -OH rotors in these molecules are evaluated using an internal rotational partition function formed by the summation of internal rotational energy levels for each rotor. In the calculation of the thermodynamic properties of ethanol (g) and 1-propanol (g), we adopted a molecular model that the vapor of each compound contains an equilibrium mixture of trans and gauche isomers. The existence of such isomers was observed spectroscopically in recent years. Our calculated results, such as C /SUP o/ /SUB p/ and S /SUP o/ (T)-S /SUP o/ (0), agree with available experimental values

  12. Organogels thermodynamics, structure, solvent role, and properties

    CERN Document Server

    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 ...

  13. Thermodynamic properties of 4f metal trifluorides

    International Nuclear Information System (INIS)

    The experimental low-temperature heat capacities of some solid 4f-block metal trifluorides were used to reveal the trends in the behavior of variable parameters in the equation that described the lattice heat capacity component in the quasi-harmonic approximation for the whole series of LnF3 (Ln La-Lu) compounds. The results were used to describe the temperature dependences of heat capacity over the temperature range from 0 K to the melting point, Tm. The measured high-temperature enthalpy increments were used to determine corrections to the quasi-harmonic description of heat capacities at T > ∼0.5Tm. The reduced Gibbs energies were calculated over the temperature range 298.15-2000 K. The thermodynamic functions of LnF3 in the gaseous state were determined over the same temperature range in the rigid rotator - harmonic oscillator approximation. All calculations were performed taking into account excited electronic states whose energies did not exceed 10000 cm-1. The reliability of the thermodynamic functions obtained was proved by the convergence of the enthalpies of sublimation calculated by the second and third laws of thermodynamics from the experimental data on saturated vapor pressures. The complete set of the consistent thermodynamic properties of these compounds is described

  14. THERMODYNAMIC PROPERTIES OF POLYDISPERSE FLUID MIXTURES

    OpenAIRE

    S.Leroch; D.Gottwald; Kahl, G

    2004-01-01

    We present a systematic study of the thermodynamic properties of a polydisperse fluid mixture. The size of the particles, σ, is assumed to be distributed according to a continuous distribution function fΣ(σ), for which we have chosen a Γ-distribution. The interatomic potentials are given by a hard core repulsion plus an adjacent attractive tail in the form of a square-well or a Yukawa potential; for the size-dependence of the attraction strength we have assumed different models. The propertie...

  15. Thermodynamic properties of black holes in de Sitter space

    OpenAIRE

    Li, Huai-Fan; Ma, Meng-Sen; Ma, Ya-Qin

    2016-01-01

    We study the thermodynamic properties of Schwarzschild-de Sitter (SdS) black hole and Reissner-Nordstr\\"{o}m-de Sitter (RNdS) black hole in the view of global and effective thermodynamic quantities. Making use of the effective first law of thermodynamics, we can derive the effective thermodynamic quantities of de Sitter black holes. It is found that these effective thermodynamic quantities also satisfy Smarr-like formula. Especially, the effective temperatures are nonzero in the Nariai limit,...

  16. Temperature of maximum density and excess thermodynamics of aqueous mixtures of methanol.

    Science.gov (United States)

    González-Salgado, D; Zemánková, K; Noya, E G; Lomba, E

    2016-05-14

    In this work, we present a study of representative excess thermodynamic properties of aqueous mixtures of methanol over the complete concentration range, based on extensive computer simulation calculations. In addition to test various existing united atom model potentials, we have developed a new force-field which accurately reproduces the excess thermodynamics of this system. Moreover, we have paid particular attention to the behavior of the temperature of maximum density (TMD) in dilute methanol mixtures. The presence of a temperature of maximum density is one of the essential anomalies exhibited by water. This anomalous behavior is modified in a non-monotonous fashion by the presence of fully miscible solutes that partly disrupt the hydrogen bond network of water, such as methanol (and other short chain alcohols). In order to obtain a better insight into the phenomenology of the changes in the TMD of water induced by small amounts of methanol, we have performed a new series of experimental measurements and computer simulations using various force fields. We observe that none of the force-fields tested capture the non-monotonous concentration dependence of the TMD for highly diluted methanol solutions. PMID:27179493

  17. Temperature of maximum density and excess thermodynamics of aqueous mixtures of methanol

    Science.gov (United States)

    González-Salgado, D.; Zemánková, K.; Noya, E. G.; Lomba, E.

    2016-05-01

    In this work, we present a study of representative excess thermodynamic properties of aqueous mixtures of methanol over the complete concentration range, based on extensive computer simulation calculations. In addition to test various existing united atom model potentials, we have developed a new force-field which accurately reproduces the excess thermodynamics of this system. Moreover, we have paid particular attention to the behavior of the temperature of maximum density (TMD) in dilute methanol mixtures. The presence of a temperature of maximum density is one of the essential anomalies exhibited by water. This anomalous behavior is modified in a non-monotonous fashion by the presence of fully miscible solutes that partly disrupt the hydrogen bond network of water, such as methanol (and other short chain alcohols). In order to obtain a better insight into the phenomenology of the changes in the TMD of water induced by small amounts of methanol, we have performed a new series of experimental measurements and computer simulations using various force fields. We observe that none of the force-fields tested capture the non-monotonous concentration dependence of the TMD for highly diluted methanol solutions.

  18. Thermodynamic Properties in Triangular-Lattice Superconductors

    Science.gov (United States)

    Ma, Xixiao; Qin, Ling; Zhao, Huaisong; Lan, Yu; Feng, Shiping

    2016-06-01

    The study of superconductivity arising from doping a Mott insulator has become a central issue in the area of superconductivity. Within the framework of the kinetic-energy-driven superconducting (SC) mechanism, we discuss the thermodynamic properties in the triangular-lattice cobaltate superconductors. It is shown that a sharp peak in the specific heat appears at the SC transition temperature T_c, and then the specific heat varies exponentially as a function of temperature for temperatures Tqualitatively the Bardeen-Cooper-Schrieffer-type temperature dependence, and has the same dome-shaped doping dependence as T_c.

  19. Thermodynamic properties of Heisenberg magnetic systems

    International Nuclear Information System (INIS)

    In this paper, we present a comprehensive investigation of the effects of the transverse correlation function (TCF) on the thermodynamic properties of Heisenberg antiferromagnetic (AFM) and ferromagnetic (FM) systems with cubic lattices. The TCF of an FM system is positive and increases with temperature, while that of an AFM system is negative and decreases with temperature. The TCF lowers internal energy, entropy and specific heat. It always raises the free energy of an FM system but raises that of an AFM system only above a specific temperature when the spin quantum number is S ≥ 1. Comparisons between the effects of the TCFs on the FM and AFM systems are made where possible

  20. Secondary phases formed during nuclear waste glass-water interactions: Thermodynamic and derived properties

    International Nuclear Information System (INIS)

    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

  1. THE DEVELOPMENT OF AQUEOUS THERMODYNAMIC MODELS: APPLICATION TO WASTE TANK PROCESSING AND VADOSE ZONE ISSUES

    Science.gov (United States)

    The presence of a wide range of radionuclides, metal ions, inorganic ligands, and organic chelating agents combined with the high base and electrolyte concentration in the Hanford waste tanks creates some unique and difficult problems in modeling the aqueous thermodynamics of the...

  2. A critique of a thermodynamic description of hydrophobic aggregation in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Blandamer, Michael J.; Abraham, Michael H

    2003-07-28

    The conclusions recently summarised by A. Marmur [J. Am. Chem. Soc. 122 (2000) 2120] concerning hydrophobic aggregation of solutes in aqueous solution are examined. The thermodynamic analysis is critically reviewed and the impact of implicit extrathermodynamic assumptions discussed. These assumptions are questioned and shown to lead to a model for hydrophobic aggregation which is flawed.

  3. A critique of a thermodynamic description of hydrophobic aggregation in aqueous solution

    International Nuclear Information System (INIS)

    The conclusions recently summarised by A. Marmur [J. Am. Chem. Soc. 122 (2000) 2120] concerning hydrophobic aggregation of solutes in aqueous solution are examined. The thermodynamic analysis is critically reviewed and the impact of implicit extrathermodynamic assumptions discussed. These assumptions are questioned and shown to lead to a model for hydrophobic aggregation which is flawed

  4. Thermodynamic and structural properties in complexing media

    International Nuclear Information System (INIS)

    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 233Pa. 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/H2O/Na2SO4/HClO4/NaClO4 and as a function of ionic strength, temperature, free sulphate, protons and chelatant concentration. First of all, the interaction between free species H+, SO4-, Na+ leads to the formation of HSO4- and NaSO4-, 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 elements like U and Np

  5. THERMODYNAMIC PROPERTIES OF POLYDISPERSE FLUID MIXTURES

    Directory of Open Access Journals (Sweden)

    S.Leroch

    2004-01-01

    Full Text Available We present a systematic study of the thermodynamic properties of a polydisperse fluid mixture. The size of the particles, σ, is assumed to be distributed according to a continuous distribution function fΣ(σ, for which we have chosen a Γ-distribution. The interatomic potentials are given by a hard core repulsion plus an adjacent attractive tail in the form of a square-well or a Yukawa potential; for the size-dependence of the attraction strength we have assumed different models. The properties of the mixture are calculated using the optimized random phase approximation (ORPA, a thermodynamic perturbation theory which is known to give reliable results in the case of simple liquids. To take into account polydispersity we combine the ORPA with the orthogonal decomposition technique where all σ-dependent functions (i.e., the correlation functions and the interatomic potentials are expanded in terms of orthogonal polynomials pi(σ associated with the weight function fΣ(σ.

  6. Thermodynamic Properties of $^{56,57}$Fe

    CERN Document Server

    Algin, E; Guttormsen, M; Larsen, A C; Mitchell, G E; Rekstad, J; Schiller, A; Siem, S; Voinov, A

    2008-01-01

    Nuclear level densities for $^{56,57}$Fe have been extracted from the primary $\\gamma$-ray spectra using ($^3$He,$^3$He$^{\\prime}\\gamma$) and ($^3$He,$\\alpha \\gamma$) reactions. Nuclear thermodynamic properties for $^{56}$Fe and $^{57}$Fe are investigated using the experimental level densities. These properties include entropy, Helmholtz free energy, caloric curves, chemical potential, and heat capacity. In particular, the breaking of Cooper pairs and single-quasiparticle entropy are discussed and shown to be important concepts for describing nuclear level density. Microscopic model calculations are performed for level densities of $^{56,57}$Fe. The experimental and calculated level densities are compared. The average number of broken Cooper pairs and the parity distribution are extracted as a function of excitation energy for $^{56,57}$Fe from the model calculations.

  7. AN INTERIM THERMODYNAMIC PROPERTY FORMULATION FOR SUPERCRITICAL n-HEXANE

    OpenAIRE

    Azzedine Abbaci; Anissa Acidi; Aicha Rizi; Salaheddine Azzouz

    2010-01-01

    Accurate information on the thermodynamic properties of supercritical fluids is highly sought for the chemical technology, especially, supercritical extraction technology. The thermodynamic properties of fluids near the critical region are strongly affected by the presence of fluctuations and therefore, can not be described by conventional equation. We have investigated an interim formulation for the behavior of the thermodynamic properties of n-hexane in the vicinity of the critical region. ...

  8. AN INTERIM THERMODYNAMIC PROPERTY FORMULATION FOR SUPERCRITICAL n-HEXANE

    Directory of Open Access Journals (Sweden)

    Azzedine Abbaci

    2010-07-01

    Full Text Available Accurate information on the thermodynamic properties of supercritical fluids is highly sought for the chemical technology, especially, supercritical extraction technology. The thermodynamic properties of fluids near the critical region are strongly affected by the presence of fluctuations and therefore, can not be described by conventional equation. We have investigated an interim formulation for the behavior of the thermodynamic properties of n-hexane in the vicinity of the critical region. For this reason we have used the so-called “crossover model” to describe the thermodynamic properties of n-hexane in a wide range of temperatures and densities around the critical point.

  9. Internally consistent thermodynamic data for aqueous species in the system Na-K-Al-Si-O-H-Cl

    Science.gov (United States)

    Miron, George D.; Wagner, Thomas; Kulik, Dmitrii A.; Heinrich, Christoph A.

    2016-08-01

    A large amount of critically evaluated experimental data on mineral solubility, covering the entire Na-K-Al-Si-O-H-Cl system over wide ranges in temperature and pressure, was used to simultaneously refine the standard state Gibbs energies of aqueous ions and complexes in the framework of the revised Helgeson-Kirkham-Flowers equation of state. The thermodynamic properties of the solubility-controlling minerals were adopted from the internally consistent dataset of Holland and Powell (2002; Thermocalc dataset ds55). The global optimization of Gibbs energies of aqueous species, performed with the GEMSFITS code (Miron et al., 2015), was set up in such a way that the association equilibria for ion pairs and complexes, independently derived from conductance and potentiometric data, are always maintained. This was achieved by introducing reaction constraints into the parameter optimization that adjust Gibbs energies of complexes by their respective Gibbs energy effects of reaction, whenever the Gibbs energies of reactant species (ions) are changed. The optimized thermodynamic dataset is reported with confidence intervals for all parameters evaluated by Monte Carlo trial calculations. The new thermodynamic dataset is shown to reproduce all available fluid-mineral phase equilibria and mineral solubility data with good accuracy and precision over wide ranges in temperature (25-800 °C), pressure (1 bar to 5 kbar) and composition (salt concentrations up to 5 molal). The global data optimization process adopted in this study can be readily repeated any time when extensions to new chemical elements and species are needed, when new experimental data become available, or when a different aqueous activity model or equation of state should be used. This work serves as a proof of concept that our optimization strategy is feasible and successful in generating a thermodynamic dataset reproducing all fluid-mineral and aqueous speciation equilibria in the Na-K-Al-Si-O-H-Cl system within

  10. Thermodynamics Properties of Mesoscopic Quantum Nanowire Devices

    Institute of Scientific and Technical Information of China (English)

    Attia A.AwadAlla; Adel H.Phillips

    2007-01-01

    We investigate the thermodynamics properties of mesoscopic quantum nanowire devices, such as the effect of electron-phonon relaxation time, Peltier coefficient, carrier concentration, frequency of this field, and channel width. The influence of time-varying fields on the transport through such device has been taken into consideration. This device is modelled as nanowires connecting to two reservoirs. The two-dimensional electron gas in a GaAs-AlGaAs heterojunction has a Fermi wave length which is a hundred times larger than that in a metal. The results show the oscillatory behaviour of dependence of the thermo power on frequency of the induced field. These results agree with the existing experiments and may be important for electronic nanodevices.

  11. Molecular geometry and boiling related thermodynamic properties

    International Nuclear Information System (INIS)

    Highlights: ► Molecular geometric factors were found to be important determinants for boiling entropy and thus the boiling temperature. ► Only four molecular geometric factors were used in the study. ► A group contribution method was used to calculate enthalpy of boiling. ► The proposed method is simple and the estimations are in good agreement with experimental values. - Abstract: Boiling related thermodynamic properties are important parameters in research. In this study, a model integrating both additive groups and non-additive molecular geometric factors has been developed for the calculation of boiling enthalpy, entropy and temperature. The calculated values are in good agreement with the measured values of 470 compounds. This model provides a simple and accurate estimation of enthalpy of boiling, entropy of boiling and boiling temperatures with absolute average errors of 0.62 kJ/mol, 1.15 J/K · mol and 7.13 K respectively.

  12. Thermodynamic properties of the heliospheric plasma

    International Nuclear Information System (INIS)

    Plasma data from Helios A and B, IMP, ISEE 3, Pioneer 10 and 11, and Voyager 1 and 2, together with an MHD simulation model, have been used to study on a global scale the temporal and radial evolution of the solar wind's thermodynamic properties (temperature T, number density n, and entropy s). The study has given the following results: (1) Near and inside 1 AU, T and n are negatively correlated almost all the time. Outside ≅5 AU, the T,n relation evolves to become positively correlated. (2) At 1 AU, T, p, n, and β/sub i/ are dependent on the sunspot number. During the minimum of the sunspot cycle, the negative correlations between T and n are very strong. (3) The radial evolution of temperature and entropy shows that a heating process takes place for the heliospheric plasma. Between 1 and 10 AU, the entropy increases by ≅4 x 10-16 erg/K/proton. In addition, from the combined Voyager 1 and 2 observations between 1 AU and 10 AU, the solar rotation average proton temperature was found to decrease as r/sup -0.46//sup +- //sup 0.09/, a rate much slower than the r/sup -4/3/ rate predicted by the adiabatic expansion of the solar wind. We interpret this heating to be largely due to the cumulative effect of the shock process with increasing distance from the Sun. (4) The simulation model is also used to extrapolate the thermodynamic properties of the solar wind from Voyager 2 to the region of the outer heliosphere bounded by the termination shock. As the heliocentric distance increases by a factor of 10, the temperature decreases by a factor of 3, and the shock process raises the entropy by 4 x 10/sup -16/ erg/K/proton. copyright American Geophysical Union 1989

  13. Phase Behavior of Aqueous NA-K-MG-CA-CI-NO3 Mixtures: Isopiestic Measurements and Thermodynamic Modeling

    Energy Technology Data Exchange (ETDEWEB)

    M.S. Gruszkiewiez; D.A. Palmer; R.D. Springer; P. Wang; A. Anderko

    2006-09-14

    A comprehensive model has been established for calculating thermodynamic properties of multicomponent aqueous systems containing the Na{sup +}, K{sup +}, Mg{sup 2+}, Ca{sup 2+}, Cl{sup -}, and NO{sub 3}{sup -} ions. The thermodynamic framework is based on a previously developed model for mixed-solvent electrolyte solutions. The framework has been designed to reproduce the properties of salt solutions at temperatures ranging from the freezing point to 300 C and concentrations ranging from infinite dilution to the fused salt limit. The model has been parameterized using a combination of an extensive literature database and new isopiestic measurements for thirteen salt mixtures at 140 C. The measurements have been performed using Oak Ridge National Laboratory's (ORNL) previously designed gravimetric isopiestic apparatus, which makes it possible to detect solid phase precipitation. Water activities are reported for mixtures with a fixed ratio of salts as a function of the total apparent salt mole fraction. The isopiestic measurements reported here simultaneously reflect two fundamental properties of the system, i.e., the activity of water as a function of solution concentration and the occurrence of solid-liquid transitions. The thermodynamic model accurately reproduces the new isopiestic data as well as literature data for binary, ternary and higher-order subsystems. Because of its high accuracy in calculating vapor-liquid and solid-liquid equilibria, the model is suitable for studying deliquescence behavior of multicomponent salt systems.

  14. Aqueous phase chemical properties of transactinides

    International Nuclear Information System (INIS)

    65-s 261Rf and 34-s 262Ha have been produced at the Lawrence Berkeley Laboratory 88-Inch Cyclotron by the 248Cm(18O,5n) and 249Bk(18O,5n) reactions, respectively. These isotopes of element 104 and 105 are produced at a one atom per minute rate, and rapid chemical separations are performed on a one-minute time scale. They are identified by detecting the α- and SF radiations from their decay. First aqueous phase chemical separations of Rf and Ha determined their primary oxidation states in aqueous solution, placing them in the periodic table at the bottom of groups 4 and 5, respectively, and confirming Seaborg's actinide concept. More recently, experiments measuring the chemical properties in more detail have uncovered some interesting and unexpected trends in periodic table properties

  15. Thermodynamics of uranium and nitric acid extraction from aqueous solution of TBP/diluent

    International Nuclear Information System (INIS)

    A thermodynamically consistent procedure for predicting distribution equilibria for uranyl nitrate and nitric acid between an aqueous solution and 30 vol % tributyl phosphate (TBP) in a hydrocarbon diluent is studied. Experimental work is developed in order to obtain equilibrium data for the system uranyl nitrate, nitric acid, water and 30 vol % TBP in n-dodecane, at 250C and 400C. The theoretical equilibrium data, obtained with the aid of a computer, are compared with the experimental results. (Author)

  16. Thermodynamic Modeling of Surface Tension of Aqueous Electrolyte Solution by Competitive Adsorption Model

    OpenAIRE

    Mohamad Javad Kamali; Zakarya Kamali; Gholamhossein Vatankhah

    2015-01-01

    Thermodynamic modeling of surface tension of different electrolyte systems in presence of gas phase is studied. Using the solid-liquid equilibrium, Langmuir gas-solid adsorption, and ENRTL activity coefficient model, the surface tension of electrolyte solutions is calculated. The new model has two adjustable parameters which could be determined by fitting the experimental surface tension of binary aqueous electrolyte solution in single temperature. Then the values of surface tension for other...

  17. Thermodynamic study of aqueous 2-(isopropylamino)ethanol. A sterically hindered new amine absorbent for CO2 capture

    International Nuclear Information System (INIS)

    Highlights: • Density and ultrasound speeds were measured in 38 aqueous mixtures of 2-(isopropylamino)ethanol. • Excess molar and limiting molar and partial molar properties were derived and interpreted. • Temperature and composition derivatives of different order give relevant hydration and molecular aggregation information. • A quantitative measure of the screening effect to the H-bonding ability of the amine group is proposed. - Abstract: Simultaneous measurements of density and sound speed, at five temperatures, T = (283.15 to 303.15) K and over the whole composition range were performed in 38 aqueous mixtures of 2-(isopropylamino)ethanol (IPAE), a sterically hindered amine of new generation with potential use in CO2 capture. Composition and temperature effects on different molar, excess molar, apparent molar and partial molar properties such as volume, isobaric expansion and isentropic compression are analysed, in order to assess different changes in the hydration and association patterns, across the entire composition range. A quantitative measure of the screening effect produced by the bulky hydrophobic part of IPAE to the H-bonding ability of the –NH group to the water molecules, is proposed. A comparison of the different thermodynamic properties, derived for this system, with those for the aqueous system of 2-(ethylamino)ethanol (EEA), is made. This last compound has a common structural –NHCH2CH2OH group sequence and a smaller and linear hydrophobic part

  18. Physicochemical and thermodynamic characterization of N-alkyl-N-methylpyrrolidinium bromides and its aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Zawadzki, Maciej, E-mail: mzawadzki@ch.pw.edu.pl; Królikowska, Marta; Lipiński, Paweł

    2014-08-10

    Highlights: • The aqueous solutions of bromide-based ionic liquids have been studied. • The synthesis and basic thermal characterization of pure IL have been done. • The density, dynamic viscosity, SLE and VLE have been determined. • The experimental data have been correlated using appropriate equations. - Abstract: This work is a continuation of our research of ionic liquids to investigate the physicochemical and thermodynamic properties of (ionic liquid + water) binary mixtures as a novel alternative working pair for the absorption heat pump cycle. In this work, a series of organic salts: N-propyl-N-methyl-pyrrolidinium bromide, [C{sub 1}C{sub 3}PYR]Br; N-butyl-N-methylpyrrolidinium, [C{sub 1}C{sub 4}PYR]Br and N-pentyl-N-methylpyrrolidinium bromide, [C{sub 1}C{sub 5}PYR]Br have been synthesized. The structures of new compounds have been confirmed using NMR spectra and elementary analysis. The basic thermal characterization of pure ILs, including temperature and enthalpy of phase transition (T{sub tr}, Δ{sub tr}H), temperature and enthalpy of melting (T{sub m,} Δ{sub m}H) have been measured using a differential scanning microcalorimetry technique (DSC). Decomposition temperature of the tested ILs were detected by the simultaneous TG/DTA experiments. The effect of temperature on the density (ρ) and dynamic viscosity (η) is reported over a wide temperature range from 298.15 to 343.15 K at ambient pressure. From experimental density data, the excess molar volumes (V{sup E}) were calculated and correlated using Redlich–Kister equation. The isothermal vapour–liquid phase equilibria (VLE) have been measured by an ebulliometric method at wide temperature range from 328.15 to 368.15 K and pressure up to 85 kPa. Experimental data have been correlated by means of NRTL equation. The solid–liquid phase equilibria (SLE) for the tested binary mixtures have been determined over whole composition range using dynamic method. The NRTL equation using parameters

  19. Thermodynamics

    CERN Document Server

    Solanki, Arun

    2008-01-01

    The comprehension of the laws which govern any material system is greatly facilitated by considering the energy and entropy of the system in various states of which it is capable. As in the case of simply mechanics systems, the performance of mechanical work, the function which expresses the capability of the system for this kind of action also plays the leading part in the theory of equilibrium. The present book is written to explain the basic concepts, theories and equilibrium concerning thermodynamics of fluids and stationary systems, geometrical representation of thermodynamic properties

  20. Thermodynamic properties of black holes in de Sitter space

    CERN Document Server

    Li, Huai-Fan; Ma, Ya-Qin

    2016-01-01

    We study the thermodynamic properties of Schwarzschild-de Sitter (SdS) black hole and Reissner-Nordstr\\"{o}m-de Sitter (RNdS) black hole in the view of global and effective thermodynamic quantities. Making use of the effective first law of thermodynamics, we can derive the effective thermodynamic quantities of de Sitter black holes. It is found that these effective thermodynamic quantities also satisfy Smarr-like formula. Especially, the effective temperatures are nonzero in the Nariai limit, which is consistent with the idea of Bousso and Hawking. By calculating heat capacity and Gibbs free energy, we find SdS black hole is always thermodynamically stable and RNdS black hole may undergoes phase transition at some points.

  1. A computationally effective formulation of the thermodynamic properties of LiBr-H2O solutions from 273 to 500 K over full composition range

    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

  2. Stability of mineral matter in aqueous media of the Chernobyl Unit-4 Shelter: Thermodynamic evaluation

    International Nuclear Information System (INIS)

    A special geochemical environment exists within the Shelter (Sarcophagus) erected in 1986 over the destroyed Unit-4 of Chernobyl nuclear power plant (NPP). Based upon the available in situ and compositional data, thermodynamic models of solid-aqueous interactions were developed to clarify the leaching behavior of various materials within the Shelter. The Selektor-A code, based on a convex programming approach to Gibbs free energy minimization, was used for the calculations. A built-in flexible hybrid thermodynamic database for the system Na-K-Ca-Mg-Cl-S-N-H-O-Si-P-Fe-Al-Sr-Cs was extended with the critically selected and matched parameters for aqueous species and solid phases in the U-Zr-Si-O-H subsystem, secondary U-minerals, mineral phases of fully hydrated Portland cements and U-bearing zircons. Modeling results show that the Shelter Waters can selectively leach a significant quantity of U and Si from the fuel-containing masses, while Zr, Fe, Ca, Mg and some other components are rather insoluble. Serpentinite, assemblages of fully-hydrated phases of Portland cements, and oxidation products of steel structural elements are estimated to be sufficiently stable in the aqueous environment of the Shelter. Calculations also define some feasible pathways for secondary mineral formation from evaporation of Shelter water solutions and interactions between these waters with the mineral matter inside the Shelter

  3. Thermodynamical properties and thermoelastic coupling of complex macroscopic structure

    International Nuclear Information System (INIS)

    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

  4. Measurement of Thermodynamic Properties of Titanium Aluminum Alloys

    Science.gov (United States)

    Mehrotra, Gopal

    1995-01-01

    This final report is a summary of the work done by Professor Mehrotra at NASA Lewis Research Center. He has worked extensively on the measurement of thermodynamic properties of titanium aluminum alloys over the past six years.

  5. Ammonia-water system : Part I. Thermodynamic properties

    International Nuclear Information System (INIS)

    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.)

  6. Critical review of the chemistry and thermodynamics of technetium and some of its inorganic compounds and aqueous species

    International Nuclear Information System (INIS)

    Chemical and thermodynamic data for Technetium (Tc) and some of its inorganic compounds and aqueous species are reviewed here. Major emphasis is given to systems with potential geochemical applications, especially the geochemistry of radioactive waste disposal. Compounds considered include oxides, hydroxides, hydrates oxides, halides, oxyhalides, double halides, and sulfides. The aqueous species considered include those in both noncomplexing media (pertechnetates, technetates, aquo-ions, and hydrolyzed cations) and complexing media (halides, sulfates, and phosphates). Thermodynamic values are recommended for specific compounds and aqueous ions when reliable experimental data are available. Where thermodynamic data are inadequate or unavailable, the chemistry is still discussed to provide information about what needs to be measured, and which chemistry needs to be clarified. A major application of these thermodynamic data will be for chemical equilibrium modeling and for construction of potential-pH diagrams for aqueous solutions. Unfortunately, the present lack of data precludes such calculations for complexing aqueous media. The situation is much better for noncomplexing aqueous media, but the chemistry and thermodynamics of cationic Tc(V) species and hydrolyzed Tc(III) species are poorly understood. 240 references, 6 tables

  7. OPTICAL PROPERTIES OF CARBAMIDE AQUEOUS SOLUTIONS

    Directory of Open Access Journals (Sweden)

    E. V. Avramenko

    2016-03-01

    Full Text Available Subject of Research. The paper presents the results of measurements of refractometric properties (refractive index n, its temperature factor dn/dt and the ultraviolet spectral absorption in carbonic acid diamide aqueous solutions (carbamide depending on solid residue mass fraction md = 0-50 % and on temperaturet = 10-70 °C.Method of Research. Laboratory methods ofliquid-phase medium refractometry and ultraviolet spectrophotometry were applied for the research. We carried out computational modeling of electronic states spectrum for the carbonic acid diamide molecule and theoretical calculation of the fundamental electronic absorption of the molecule in the ultraviolet wavelenght region.Main Results. We have established that the solution concentration md has a nonlinear character and may be represented by the quadratic polynomial with the error Δn= ± 0,0005. We have shown the refractive indexdependence on temperature n(t changes in linear fashion att = 10-70 °C.At that, the inclination of lines n(t increases at the increase of md; so, the temperature factor dn/dt may be approximated by the quadratic polynomial. Transmission spectra of solutions in the spectral region λ= 225-760 nm have no special features except for the sharp edge in the short-wavelength region; the fundamental electronic absorptionis responsible for it. We have established that dispersion dependences of the refraction index n(λ;md in aqueous solutions of carbamide at λ= 360-760 nm and at md = 0-50 % may be calculated with the satisfactory error without additional adjustable parameters from the ultraviolet absorption data in terms of the one-dimentional oscillator Lorentz model.PracticalRelevance. Representedmeasurements of carbonic acid diamide aqueous solutions optical properties may be applied for the adjustment and calibration of commercial refractometers at processing lines of the AdBlue reagent manufacture for the selective catalytic reduction (SCR of motor transport

  8. Thermodynamic properties of lanthanum and lanthanide dichlorides

    International Nuclear Information System (INIS)

    The critical analysis of the data on the LnCl2 (Ln = La-Lu) structure, oscillation frequencies and thermodynamic functions is carried out. The thermodynamic functions of 15 molecules LnCl2 are calculated in approximation of the rigid rotator-harmonic oscillator model at 298,15, 1000 and 1500 Deg C. The lacking molecular constants of the rare earth elements dichlorides are evaluated on the basis of the empiric regularities of their change in the series of the lanthanide compounds. The data on the energies by excitation of the low-lying (-1) electron states of the rare earth element two and three charge ions are applied for consideration of the electron constituent in the thermodynamic functions

  9. Biosorption of Cr (VI) ion from aqueous solution by maize husk: isothermal, kinetics and thermodynamic study

    International Nuclear Information System (INIS)

    The kinetics, equilibrium and thermodynamic of the biosorption of Cr (VI) ion onto maize husk biomass from aqueous solution were investigated. The effects of contact time, initial metal concentration, pH, temperature as well as modification with oxalic acid on biosorption capacity were studied. The maximum biosorption capacity of the untreated corn shaft biomass (UTCS) was found to be 28.49 mg g-1 which slightly increased to 29.33 mg g/sup -1/ when treated with oxalic acid treated corn shaft biomass (ATCS). The kinetics studies showed that the biosorption process of the metal ion fitted well with second order model. The calculated thermodynamic parameters (delta Go, delta Ho and delta S') showed that the biosorption of Cr (VI) ion onto the biomass maize husk is feasible, spontaneous and exothermic in nature. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Noh, Seunghyo; Kwak, Dohyun; Lee, Juseung; Kang, Joonhee; Han, Byungchan [Daegu Gyeongbuk Institute of Science and Technology, Daegu (Korea, Republic of)

    2014-03-15

    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.

  11. Kinetics and thermodynamics of aluminum oxide nanopowder as adsorbent for Fe (III from aqueous solution

    Directory of Open Access Journals (Sweden)

    Mohamed A. Mahmoud

    2015-06-01

    Full Text Available Batch adsorption of Fe (III from aqueous solution by aluminum oxide nanopowder was studied in batch system. The removal efficiency (99.9% was obtained at pH 4 and 50 min contact time. The results indicate that the process follows Langmuir isotherm and pseudo-second-order kinetics model. As well as the thermodynamic data indicated that the exothermic nature process. The values of enthalpy (ΔH°, mean free energy (E and activation energy (Ea indicate that the adsorption process is physical sorption.

  12. Thermodynamic Modeling of Surface Tension of Aqueous Electrolyte Solution by Competitive Adsorption Model

    Directory of Open Access Journals (Sweden)

    Mohamad Javad Kamali

    2015-01-01

    Full Text Available Thermodynamic modeling of surface tension of different electrolyte systems in presence of gas phase is studied. Using the solid-liquid equilibrium, Langmuir gas-solid adsorption, and ENRTL activity coefficient model, the surface tension of electrolyte solutions is calculated. The new model has two adjustable parameters which could be determined by fitting the experimental surface tension of binary aqueous electrolyte solution in single temperature. Then the values of surface tension for other temperatures in binary and ternary system of aqueous electrolyte solution are predicted. The average absolute deviations for calculation of surface tension of binary and mixed electrolyte systems by new model are 1.98 and 1.70%, respectively.

  13. Organofunctionalized Amazon smectite for dye removal from aqueous medium-Kinetic and thermodynamic adsorption investigations

    International Nuclear Information System (INIS)

    The objective of this study is to examine the adsorption behavior of Sumifix Brilliant Orange 3R textile dye from aqueous solution on smectite sample, an abundant Amazon clay. The original smectite clay mineral has been collected from Amazon region, Brazil. The compound 2-aminomethylpyridine was anchored onto smectite surface by heterogeneous route. The ability of these materials to remove the Sumifix Brilliant Orange 3R textile dye from aqueous solution was followed by a series of adsorption isotherms, using a batchwise process. The maximum number of moles adsorbed was determined to be 1.26 and 2.07 mmol g-1 for natural and modified clay samples, respectively. The energetic effects caused by dye cations adsorption were determined through calorimetric titrations. Thermodynamics indicated the existence of favorable conditions for such dye-nitrogen interactions.

  14. 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.

  15. Theoretical investigation of the thermodynamic properties of metallic thin films

    International Nuclear Information System (INIS)

    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

  16. 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...

  17. Thermodynamical properties of metric fluctuations during inflation

    CERN Document Server

    Bellini, M

    2001-01-01

    I study a thermodynamical approach to scalar metric perturbations during the inflationary stage. In the power-law expanding universe here studied, I find a negative heat capacity as a manifestation of superexponential growing for the number of states in super Hubble scales. The power spectrum depends on the Gibbons-Hawking and Hagedorn temperatures.

  18. Thermodynamical and excess thermoacoustical study on some monosaccharide (glucose) with enzyme amylase in aqueous media at 298.15 K

    Science.gov (United States)

    Nithiyanantham, S.; Palaniappan, L.

    2011-03-01

    Ultrasonic velocity (U), density (ρ) and viscosity (η) measurements have been carried out in three ternary mixtures of glucose with amylase in aqueous medium at 298.15 K. The experimental data have been used to calculate some derived parameters such as acoustical impedance (Z), relative association (RA), Rao's constant (R), Wada's constant (W), relaxation time (τ), relaxation amplitude (α/f2), relaxation strength (r), and some excess thermodynamical properties like excess adiabatic compressibility (βE), excess free length (LfE) excess free volume (VfE), excess internal pressure (πiE) and excess acoustical impedance (ZE). The above parameters have been evaluated and discussed in light of molecular interactions in the mixture.

  19. Rheological Properties of Aqueous Nanometric Alumina Suspensions

    Energy Technology Data Exchange (ETDEWEB)

    Chuanping Li

    2004-12-19

    Colloidal processing is an effective and reliable approach in the fabrication of the advanced ceramic products. Successful colloidal processing of fine ceramic powders requires accurate control of the rheological properties. The accurate control relies on the understanding the influences of various colloidal parameters on the rheological properties. Almost all research done on the rheology paid less attention to the interactions of particle and solvent. However, the interactions of the particles are usually built up through the media in which the particles are suspended. Therefore, interactions of the particle with the media, the adsorbed layers on the particle surface, and chemical and physical properties of media themselves must influence the rheology of the suspension, especially for the dense suspensions containing nanosized particles. Relatively little research work has been reported in this area. This thesis addresses the rheological properties of nanometric alumina aqueous suspensions, and paying more attention to the interactions between particle and solvent, which in turn influence the particle-particle interactions. Dense nanometric alumina aqueous suspensions with low viscosity were achieved by environmentally-benign fructose additives. The rheology of nanometric alumina aqueous suspensions and its variation with the particle volume fraction and concentration of fructose were explored by rheometry. The adsorptions of solute (fructose) and solvent (water) on the nanometric alumina particle surfaces were measured and analyzed by TG/DSC, TOC, and NMR techniques. The mobility of water molecules in the suspensions and its variation with particle volume fractions and fructose additive were determined by the {sup 17}O NMR relaxation method. The interactions between the nanometric alumina particles in water and fructose solutions were investigated by AFM. The results indicated that a large number of water layers were physically bound on the particles

  20. Thermodynamic properties of vitamin B2

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Temperature dependence of heat capacity of vitamin B2 has been measured by precision adiabatic vacuum calorimetry. • The thermodynamic functions of the vitamin B2 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 ΔcH° and the thermodynamic parameters ΔfH°, ΔfS°, ΔfG° have been calculated. - Abstract: In the present work temperature dependence of heat capacity of vitamin B2 (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 B2, 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 ΔcH° and the thermodynamic parameters ΔfH°, ΔfS°, ΔfG° and of reaction of formation of the riboflavin from simple substances at T = 298.15 K and p = 0.1 MPa have been calculated

  1. Self-association and thermodynamic behavior of etilefrine hydrochloride in aqueous electrolyte solution

    International Nuclear Information System (INIS)

    Highlights: • The self-association of etilefrine HCl in aqueous solution has been studied. • Conductivity and 1H NMR measurements were used to study the self association. • The critical micelle concentrations and the degree of ionizations were calculated. • The effect of different temperatures and NaCl concentrations were studied. • The thermodynamic parameters of self association of etilefrine HCl were evaluated. - Abstract: The self-association (micellization) behavior of etilefrine HCl, an amphiphilic drug, in aqueous electrolyte solution has been investigated as a function of temperature and sodium chloride (NaCl) concentration by conductivity and 1H NMR measurements. The critical micelle concentration (CMC) was calculated from the inflection in the data obtained from both techniques. The CMC and the degree of ionization (α) values were determined over the temperature range (298.15 to 313.15) K in water and in presence of different concentrations of NaCl. The thermodynamic parameters of micellization for etilefrine HCl i.e. the standard Gibbs free energy change ΔG°m, the standard enthalpy change, ΔH°m, and the standard entropy change, ΔS°m, were evaluated according to the pseudo-phase model. The obtained CMC values, in presence and absence of electrolyte, showed an inverted U-shaped behavior. While the degree of micelle ionization (α) showed a linear response to the increase in temperature in absence of electrolyte, addition of NaCl did not cause a specific response

  2. Cyanide and antimony thermodynamic database for the aqueous species and solids for the EPA-MINTEQ geochemical code

    Energy Technology Data Exchange (ETDEWEB)

    Sehmel, G.A.

    1989-05-01

    Thermodynamic data for aqueous species and solids that contain cyanide and antimony were tabulated from several commonly accepted, published sources of thermodynamic data and recent journal article. The review does not include gases or organic complexes of either antimony or cyanide, nor does the review include the sulfur compounds of cyanide. The basic thermodynamic data, ..delta..G/sub f,298//sup o/, ..delta..H/sub f,298//sup o/, and S/sub f//sup o/ values, were chosen to represent each solid phase and aqueous species for which data were available in the appropriate standard state. From these data the equilibrium constants (log K/sub r,298//sup o/) and enthalpies of reaction (..delta..H/sub r,298//sup o/) at 298 K (25/degree/C) were calculated for reactions involving the formation of these aqueous species and solids from the basic components. 34 refs., 14 tabs.

  3. Cyanide and antimony thermodynamic database for the aqueous species and solids for the EPA-MINTEQ geochemical code

    International Nuclear Information System (INIS)

    Thermodynamic data for aqueous species and solids that contain cyanide and antimony were tabulated from several commonly accepted, published sources of thermodynamic data and recent journal article. The review does not include gases or organic complexes of either antimony or cyanide, nor does the review include the sulfur compounds of cyanide. The basic thermodynamic data, ΔG/sub f,298//sup o/, ΔH/sub f,298//sup o/, and S/sub f//sup o/ values, were chosen to represent each solid phase and aqueous species for which data were available in the appropriate standard state. From these data the equilibrium constants (log K/sub r,298//sup o/) and enthalpies of reaction (ΔH/sub r,298//sup o/) at 298 K (25/degree/C) were calculated for reactions involving the formation of these aqueous species and solids from the basic components. 34 refs., 14 tabs

  4. Thermodynamic and kinetic studies of cadmium adsorption from aqueous solution onto rice husk

    Directory of Open Access Journals (Sweden)

    P. Senthil Kumar

    2010-06-01

    Full Text Available The adsorption behavior of rice husk for cadmium ions from aqueous solutions has been investigated as a function of appropriate equilibrium time, adsorbent dose, temperature, adsorbate concentrations and pH in a batch system. Studies showed that the pH of aqueous solutions affected cadmium removal with the result that removal efficiency increased with increasing solution pH. The maximum adsorption was 98.65% at solution pH 6, contact time 60 min and initial concentration of 25 mg/L. The experimental data were analysed by the Langmuir, Freundlich and Temkin models of adsorption. The characteristic parameters for each isotherm and related correlation coefficients have been determined.  Thermodynamic parameters such as,  and have also been evaluated and it has been found that the sorption process was feasible, spontaneous and exothermic in nature. The kinetics of the sorption were analysed using the pseudo-first order and pseudo-second order kinetic models. Kinetic parameters, rate constants, equilibrium sorption capacities and related correlation coefficients for each kinetic model were calculated and discussed. It was shown that the adsorption of cadmium could be described by the pseudo-second order equation, suggesting that the adsorption process is presumably a chemisorption. The rice husk investigated in this study showed good potential for the removal of cadmium from aqueous solutions. The goal for this work is to develop inexpensive, highly available, effective metal ion adsorbents from natural waste as alternative to existing commercial adsorbents.

  5. The thermodynamic properties of quinoline and isoquinoline: Topical report

    Energy Technology Data Exchange (ETDEWEB)

    Steele, W.V.; Archer, D.G.; Chirico, R.D.; Collier, W.B.; Gammon, B.E.; Hossenloop, I.A.; Nguyen, A.; Smith, N.K.

    1988-03-01

    Measurements leading to the calculation of the ideal-gas thermodynamic properties for quinoline and isoquinoline are reported. Thermodynamic and thermophysical properties were determined by adiabatic heat-capacity calorimetry, comparative ebulliometry, densimetry, and combustion calorimetry. Vibrational spectra of quinoline and isoquinoline were assigned. Entropies and enthalpies for the ideal-gas state from the claorimetric measurements and from the vibrational assignments were derived and compared. Entropies, enthalpies, and Gibbs energies of formation were derived at selected temperatues between T..-->..0 and 1000 K. new density measurements for benzene are reported. 55 refs., 11 figs., 16 tabs.

  6. Partial thermodynamic properties and defective structure of oxide phases

    International Nuclear Information System (INIS)

    Partial thermodynamic properties and defective structure of oxide phases have been considered and evaluation of the properties is made, using various correlations to create a correct statisticothermodynamic model of the defective structure. The dependences OEHsub(Osub(2)) deg, ΔSsub(Osub(2)) deg and ΔSsub(Osub(2)) deg (ΔHsub(Osub(2)) deg) are presented for such oxides as VOsub(1+-x), VOsub(3/2+x), VOsub(2+-x), ZrOsub(2-x), HfOsub(2-x), WOsub(2+x), Wosub(3-x). Ways to evaluate the type of defects using the thermodynamic dependences are shown: 1) the use of thermodynamic data in the method of quasichemical equilibrium of defects; 2) the method, based on the establishment of defective structure according to linear dependence of oxygen activity on x in MOsub(s+-x) in the case of certain types of defects; 3) the method of model selection of a compound defective structure comparing the reduced dependences of partial thermodynamic functions of the phase composition with the ones, obtained experimentally. Models of complex types of defective structure during partial ordering of the defects for CeOsub(2-x) and UOsub(2+x) are analyzed. Despite the multiplicity of assumptions and insufficiency of application limits study the model of energy levels is admitted to be the most perpective statistical model to determine partial thermodynamic properties of nonstoichiometric compounds with a complex defective structure, experimental determination of which is hampered

  7. Micellization properties of cationic gemini surfactants in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Łudzik, K., E-mail: kasialudzik@tlen.pl [Department of Physical Chemistry, University of Łódź, Pomorska 165, 90-236 Łódź (Poland); Piekarski, H.; Kubalczyk, K.; Wasiak, M. [Department of Physical Chemistry, University of Łódź, Pomorska 165, 90-236 Łódź (Poland)

    2013-04-20

    Highlights: ► We measured the d and c{sub p} of for the aqueous solutions of 8-6-8 and 8-12-8 surfactants. ► We analyzed the α{sub T} = f (m), V{sub ϕ} = f (m), c{sub p} = f (m) and C{sub p,ϕ} = f (m). ► The inflection point in the curves of the C{sub p,ϕ} = f (m) corresponds to the c.m.c. ► We analyzed thermodynamics parameters of the micellization for the surfactants. - Abstract: The main goal of this work was to investigate the self-assembly process for water solutions of two gemini surfactants, which differ in spacer chain length, at wide range of temperatures. For this reason the aqueous solutions of hexylene-1,6-bis(dimethyl-octylammonium bromide) and dodecylene-1,12-bis(dimethyloctylammonium bromide) have been examined by the calorimetric (DSC) and densimetric methods within the 293–323 K and 288–323 K temperature range, respectively. The analysis of c{sub p} values obtained for the examined systems allowed to propose an alternative way to estimate the region where micellization process can occur. The observed temperature dependence of the c.m.c. for surfactants investigated shows a typical shape for ionic gemini surfactants. This behavior was explained as a resultant of two competing effect: decrease in the hydrophilic properties of the surfactant molecule and decrease in the hydrophobic hydration of the alkyl chain along with the temperature increase. The enthalpy of micellization ΔH{sub mic} and other thermodynamics parameters associated with the micellization process: ΔG{sub mic}, ΔS{sub mic} and ΔC{sub p} {sub mic} were calculated on the base of the pseudo-phase separation model. As expected, more exothermic enthalpies of micellization are observed with increasing temperature for both the surfactants investigated in this work.

  8. Experimental measurement and thermodynamic modelling of phase equilibria of semi-clathrate hydrates of (CO2 + tetra-n-butyl-ammonium bromide) aqueous solution

    International Nuclear Information System (INIS)

    Highlights: • Hydrate phase equilibrium data are reported for the CO2 + TBAB aqueous solutions systems. • A thermodynamic model is developed to predict the dissociation conditions of the latter systems. • The properties of the aqueous phase are calculated using the AMSA-NRTL electrolyte model. • The model satisfactorily predicts the experimental data with an AARD% of approximately 13%. - Abstract: Comprehensive studies on semi-clathrate hydrates phase equilibria are still required to better understand characteristics of this type of clathrates. In this communication, new experimental data on the dissociation conditions of semi-clathrate hydrates of {carbon dioxide + tetra-n-butyl-ammonium bromide (TBAB)} aqueous solution are first reported in a wide range of TBAB concentrations and at different pressures and temperatures. A thermodynamic model is then proposed to predict the dissociation conditions of the semi-clathrate hydrates for the latter system. The (hydrate + TBAB) aqueous solution (H + Lw) phase equilibrium prediction is considered based on Gibbs free energy minimization approach. A modified van der Waals–Platteeuw solid solution theory developed based on the (H + Lw) equilibrium information is employed to predict the dissociation conditions of semi-clathrate hydrates of carbon dioxide + TBAB. The properties of the aqueous solution are estimated using the AMSA-NRTL electrolyte model (considering the association and hydration of ions). The Peng–Robinson equation of state is used for estimating the gas/vapour phase properties. Results show that the proposed model satisfactorily predicts the experimental values with an average absolute relative deviation of approximately 13%

  9. Crevice corrosion properties and chemical thermodynamic evaluation of the corrosion system

    International Nuclear Information System (INIS)

    Crevice corrosion properties of 304 Stainless Steel (304SS) and Alloy 600 in aqueous oxalic acid solution were evaluated and the results were analyzed by chemical thermodynamic calculation. The corrosion rate of 304SS in the low pH region was highly accelerated, however that of Alloy 600 was not. Crevice corrosion resistance of those alloys critically relies on the formation of protective layer (NiC2O4) which was formed on the surface of Alloy 600 only. FeC2O4 did not contribute to corrosion resistance which was formed on the surface of 304SS at the low pH region. (author)

  10. 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 *})

  11. Thermodynamic Property Models for Unburned Mixtures and Combustion Gases

    OpenAIRE

    Messina Michele; Lanzafame Rosario

    2006-01-01

    New mathematical functions, with the functional form of a fifth order logarithmic polynomial, have been developed. These polynomials have been used to describe gases’ thermodynamic properties, and have been utilized for combustion processes, with “frozen composition” and “shifting equilibrium composition” evaluation. The logarithmic polynomials present the advantage of covering a wide range of temperatures with only a single mathematical funct...

  12. On lumped models for thermodynamic properties of simulated annealing problems

    OpenAIRE

    Andresen, Bjarne; Hoffmann, Karl Heinz; Mosegaard, Klaus; Nulton, Jim; Pedersen, Jacob Mørch; Salamon, Peter

    1988-01-01

    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.

  13. Thermodynamical property of entanglement entropy for excited states.

    Science.gov (United States)

    Bhattacharya, Jyotirmoy; Nozaki, Masahiro; Takayanagi, Tadashi; Ugajin, Tomonori

    2013-03-01

    We argue that the entanglement entropy for a very small subsystem obeys a property which is analogous to the first law of thermodynamics when we excite the system. In relativistic setups, its effective temperature is proportional to the inverse of the subsystem size. This provides a universal relationship between the energy and the amount of quantum information. We derive the results using holography and confirm them in two-dimensional field theories. We will also comment on an example with negative specific heat and suggest a connection between the second law of thermodynamics and the strong subadditivity of entanglement entropy. PMID:23496702

  14. Thermodynamical properties of Strunz’s quantum dissipative models

    International Nuclear Information System (INIS)

    The existence of the negative of specific heat from quantum dissipative theory is investigated. Strunz’s quantum dissipative model will be used in this studies. The thermodynamical properties will be studied starts out from the thermo-dynamic partition function of the dissipative system. The path integral technique is used to calculate the partition function under consideration. The results shows that the specific heat can be negative if the damping parameter more than a half the oscillator frequency and also occur at low temperatures. For damping factor greater than the frequency of harmonic oscillator then specific heat will oscillate at low temperatures and approaching normal conditions at a high temperature

  15. Thermodynamic properties of cadmium in lead amalgam dilute solution

    International Nuclear Information System (INIS)

    Investigation of thermodynamic properties of cadmium dilute solutions in lead amalgam is carried out by means of electromotive force technique within 453-523 K temperature range. Cadmium thermodynamic functions are calculated: activity, activity ratio, Libbs partial energy and its excess value and integral characteristics, respectively. When changing cadmium content from 0.01 up to 0.1 χcd at T=473 K, logarithm of activity ratio does not depend on alloy composition, that is, Heury's law is fulfilled. Increase of cadmium content in amalgam results in the essential reduction of mercury and cadmium reaction

  16. Thermodynamical properties of Strunz’s quantum dissipative models

    Energy Technology Data Exchange (ETDEWEB)

    Zen, Freddy P. [Theoretical Physics Laboratory (THEPI), Department of Physics, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung 40132 (Indonesia); Indonesia Center for Theoretical and Mathematical Physics (ICTMP), Jl. Ganesha 10, Bandung 40132 (Indonesia); Sulaiman, A. [Indonesia Center for Theoretical and Mathematical Physics (ICTMP), Jl. Ganesha 10, Bandung 40132 (Indonesia); Geostech Laboratory, Badan Pengkajian dan Penerapan Teknologi (BPPT), Kawasan Puspiptek Serpong, Tanggerang Selatan (Indonesia)

    2015-09-30

    The existence of the negative of specific heat from quantum dissipative theory is investigated. Strunz’s quantum dissipative model will be used in this studies. The thermodynamical properties will be studied starts out from the thermo-dynamic partition function of the dissipative system. The path integral technique is used to calculate the partition function under consideration. The results shows that the specific heat can be negative if the damping parameter more than a half the oscillator frequency and also occur at low temperatures. For damping factor greater than the frequency of harmonic oscillator then specific heat will oscillate at low temperatures and approaching normal conditions at a high temperature.

  17. Thermodynamic Properties of Eutectic Silumins Doped by Transition Metals

    Science.gov (United States)

    Kanibolotsky, D. S.; Stukalo, V. A.; Lisnyak, V. V.

    2004-05-01

    The thermodynamic properties of the liquid silumins (Al0.879Si0.121)1-xTrx, where Tr = Cu, Fe, Ni and Ti, have been measured, using the electromotive force method at 1040 K. It has been found that diluted solutions of Fe or Ni in eutectic silumins at Tr molar fractions of 0 Cu show negative deviations from Raoult's law for aluminium at the studied concentrations. Thermodynamic activity of Al in the silumins decreases in the sequence of Fe→Ni→Cu→Ti for the dopants.

  18. Thermodynamic properties and phase transitions in CO2 molecular clusters

    Science.gov (United States)

    Etters, R. D.; Flurchick, K.; Pan, R. P.; Chandrasekharan, V.

    1981-01-01

    The thermodynamic properties of (CO2)N molecular aggregates of size N between 2 and 13 have been investigated. These crystallites exhibit well defined orientational order-disorder rotational transitions accompanied by a structural transition into a plastic crystallite phase. In addition, they exhibit melting and disassociation transitions. It is shown that the interpretation of experimental data, based upon dimer properties, depends crucially on these results. Equilibrium structures and orientations are also given.

  19. Thermodynamic properties of superheated and supercritical steam

    Energy Technology Data Exchange (ETDEWEB)

    Malhotra, A. [Indian Inst. of Technology, New Delhi (India). Dept. of Mechanical Engineering; Panda, D.M.R. [Dadri Gas Power Station, NTPC, Gautam Buddha Nagar (India)

    2001-07-01

    An existing formulation for steam properties is due to Irvine and Liley. Their equations are convenient to program and do not require excessive computational time to produce results. The properties computed from these equations compare favourably with standard data. An additional advantage of these equations is that they follow prescribed theoretical trends by reducing to perfect-gas behaviour away from the saturation dome. However, a difficulty with these equations is that, at pressures above 10 MPa and close to the saturation dome, unacceptably large errors (above 10%) are produced. These equations are examined in the present work with a view towards enhancing their range of application through the use of additional functions. It is shown that the errors may be reduced to within 1% over the entire range of pressures (both sub-critical and super-critical pressures) required in steam-plant calculations. (author)

  20. Thermodynamic Properties of Caprolactam Ionic Liquids

    Institute of Scientific and Technical Information of China (English)

    JIANG Lu; BAI Liguang; ZHU Jiqin; CHEN Biaohua

    2013-01-01

    A series of caprolactam ionic liquids (ILs) containing incorporated halide anions were synthesized.Their physical properties,such as melting points,heats of fusion and heat capacities,were measured by differential scanning calorimeter (DSC).The results indicate that these ionic liquids exhibit proper melting points,high value of heats of fusion,and satisfying heat capacities which are suitable for thermal energy storage applications.

  1. Thermodynamic Properties from Corresponding States Theory

    DEFF Research Database (Denmark)

    Mollerup, Jørgen

    1980-01-01

    —Leland corresponding-states theory. Different fluid approximations for mixtures have been applied to the various corresponding states approaches. The resulting computation methods have been applied to calculate saturation properties of pure fluids and separation factors in binary mixtures for some fluids commonly......A corresponding states approach has been applied to the two-constant equations of state by Wilson, Soave, Peng—Robinson, Hamam et al., Lu et al., Simonet—Behar, and Chaudron et al. in order to obtain the equivalent shape-factor correlations. The correlations derived are compared with the Leach...

  2. Thermodynamics of silicate melts: Configurational properties

    International Nuclear Information System (INIS)

    The ease with which a liquid adjusts to the shape of its container is a well-known consequence of the hallmark of the molten state, atomic mobility. Atomic mobility is the very reason why liquids flow, even though another salient feature evident through daily experience is that the viscosity increases when the temperature decreases. In fact, if crystallization does not occur, the viscosity eventually becomes so high that flow can no longer take place during the timescale of an experiment. The resulting material is a glass, i.e., a solid with the frozen-in disordered atomic arrangement of a liquid. Glasses have been produced for millennia, but the kinetic nature of the liquid-glass transition and its influence on the properties of glasses have long remained elusive. We will not specifically address these aspects, however, because they have already been extensively discussed in the geochemical literature from a relaxational (Dingweil and Webb, 1990) or thermochemical standpoint (Richet and Bottinga, 1983, 1986). In this review, we will focus on features of liquids that are directly related to atomic mobility, namely, the existence of those contributions to physical properties of liquids that have been termed configurational (Simon, 1931; Bernal, 1936)

  3. Preparation and Properties of an Aqueous Ferrofluid

    Science.gov (United States)

    Enzel, Patricia; Adelman, Nicholas B.; Beckman, Katie J.; Campbell, Dean J.; Ellis, Arthur B.; Lisensky, George C.

    1999-07-01

    Ferrofluids are colloidal suspensions of surfactant-coated magnetic particles in a liquid medium. This paper describes a simple synthesis of an aqueous-based ferrofluid that may be used in an introductory science or engineering laboratory. Magnetite (Fe3O4) particles are precipitated by combining FeCl3 and FeCl2 in a 2:1 stoichiometric ratio in aqueous ammonia solution. The resulting particles, ~10-20 nm in diameter based on powder X-ray diffraction, are then treated with aqueous tetramethylammonium hydroxide, which acts as a surfactant. When the resulting ferrofluid is placed near a magnet, it forms conical spikes. This paper also describes a method for repelling both oil- and water-based ferrofluid from solid surfaces that would otherwise be stained by the fluid. Finally, a demonstration of the interaction between ferrofluid and magnetic fields, in which ferrofluid is induced to leap upward by a stack of magnets, is described.

  4. Extended UNIQUAC model for thermodynamic modeling of CO2 absorption in aqueous alkanolamine solutions

    DEFF Research Database (Denmark)

    Faramarzi, Leila; Kontogeorgis, Georgios; Thomsen, Kaj;

    2009-01-01

    modeling and they cover a very wide range of conditions. Vapor-liquid equilibrium (VLE) data for the aqueous alkanolamine systems containing CO2 in the pressure range of 3-13,000 kPa and temperatures of 25-200 C are used. The model is also regressed with the VLE and freezing point depression data of the...... binary aqueous alkanolamine systems (MEA-water and MDEA-water). The two just mentioned types of data cover the full concentration range of alkanolamines from extremely dilute to almost pure. The experimental freezing point depression data down to the temperature of -20 degrees C are used. Experimental...... almost 230 degrees C) are included in the parameter estimation process. The previously unavailable standard state properties of the alkanolamine ions appearing in this work, i.e. MEA protonate, MEA carbamate and MDEA protonate are determined. The concentration of the species in both MEA and MDEA...

  5. Derived thermodynamic properties of alcohol + cyclohexylamine mixtures

    Directory of Open Access Journals (Sweden)

    IVONA R. RADOVIĆ

    2010-02-01

    Full Text Available Thermal expansion coefficients, α, excess thermal expansion coefficients, αE, isothermal coefficients of pressure excess molar enthalpy, (∂HE/∂pT,x, partial molar volumes, , partial molar volumes at infinite dilution, , partial excess molar volumes, , and partial excess molar volumes at infinite dilution, , were calculated using experimental densities and excess molar volumes, , data. All calculations are performed for the binary systems of cyclohexylamine with 1-propanol or 1-butanol or 2-butanol or 2-methyl-2-propanol. The Redlich–Kister polynomial and the reduced excess molar volume approach were used in the evaluation of these properties. In addition, the aim of this investigation was to provide a set of various volumetric data in order to asses the influence of temperature, chain length and position of hydroxyl group in the alcohol molecule on the molecular interactions in the examined binary mixtures.

  6. Critically Evaluated Database of Environmental Properties: The Importance of Thermodynamic Relationships, Chemical Family Trends, and Prediction Methods

    Science.gov (United States)

    Brockbank, Sarah A.; Russon, Jenna L.; Giles, Neil F.; Rowley, Richard L.; Wilding, W. Vincent

    2013-11-01

    A database containing Henry's law constants, infinite dilution activity coefficients, and solubility data of industrially important chemicals has been compiled for aqueous systems. These properties are important in predicting the fate and transport of chemicals in the environment. The structure of this database is compatible with the existing 801 database and DIADEM interface, and data are included for a subset of compounds found in the 801 database. Thermodynamic relationships, chemical family trends, and predicted values were carefully considered when designating recommended values.

  7. Effect of the thermodynamic properties of W/O microemulsions on samarium oxide nanoparticle size.

    Science.gov (United States)

    Zhu, Wenqing; Xu, Lei; Ma, Jin; Yang, Rui; Chen, Yashao

    2009-12-01

    In this work, we report the preparation of the Sm2O3 nanoparticle precursors (Sm(OH)3) via a simple W/O microemulsion process, in which microemulsions of cetyltrimethylammonium bromide (CTAB)/alkanol/1-octane/Sm(NO3)3 aqueous solution were added into sodium hydroxide (NaOH) aqueous solutions. The Sm2O3 nanoparticles were then prepared by calcining the precursors at 900 degrees C. Particularly, DeltaG(c-->i), which is the change in standard Gibbs free energy for transferring cosurfactant from the continuous phase to the microemulsion interface and can be used to estimate the thermodynamic properties of microemulsions, was determined using the dilution method. The effects of alkanol carbon chain length (1-pentanol, 1-hexanol, 1-heptanol and 1-octanol) and the reaction temperatures (298, 308, 318 and 328 K) on both DeltaG(c-->i) and Sm2O3 nanoparticle size have been investigated. Specifically, the Sm2O3 nanoparticle size, when calcined at 900 degrees C, was found to be mainly controlled by DeltaG(c-->i), and was thereby affected by the thermodynamic properties of microemulsions. The obtained products were characterized by DSC-TGA, XRD, TEM and UV-Vis. The results showed that DeltaG(c-->i) decreased with the increase in both the length of alkanol carbon chain and the reaction temperature, and the average size of Sm2O3 nanoparticles decreased as DeltaG(c-->i) decreased. The effect of microemulsion thermodynamic properties on Sm2O3 nanoparticle size reported here can provide some insights in controllable preparation of other rare earth oxide nanoparticles via the microemulsion route. PMID:19740477

  8. Thermodynamic properties of fluids from Fluctuation Solution Theory

    International Nuclear Information System (INIS)

    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

  9. Kinetics and thermodynamics of textile dye adsorption from aqueous solutions using babassu coconut mesocarp

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, Adriana P.; Santana, Sirlane A.A.; Bezerra, Cicero W.B.; Silva, Hildo A.S. [Departamento de Quimica/CCET, Universidade Federal do Maranhao, Av. dos, Portugueses S/N, Campus do Bacanga, 65080-540 Sao Luis, Maranhao (Brazil); Chaves, Jose A.P. [Colegio Universitario, Universidade Federal do Maranhao, 65080-540 Sao Luis, Maranhao (Brazil); Melo, Julio C.P. de [Institute of Chemistry, University of Campinas, UNICAMP, P.O. Box 6154, 13084-971 Campinas, Sao Paulo (Brazil); Silva Filho, Edson C. da [Quimica, Universidade Federal do Piaui, 64900-000 Bom Jesus, Piaui (Brazil); Airoldi, Claudio, E-mail: airoldi@iqm.unicamp.br [Institute of Chemistry, University of Campinas, UNICAMP, P.O. Box 6154, 13084-971 Campinas, Sao Paulo (Brazil)

    2009-07-30

    Extracted babassu coconut (Orbignya speciosa) mesocarp (BCM) was applied as a biosorbent for aqueous Blue Remazol R160 (BR 160), Rubi S2G (R S2G), Red Remazol 5R (RR 5), Violet Remazol 5R (VR 5) and Indanthrene Olive Green (IOG) dye solutions. The natural sorbent was processed batchwise while varying several system parameters such as stirring time, pH and temperature. The interactions were assayed with respect to both pseudo-first-order and second-order reaction kinetics, with the latter the more suitable kinetic model. The maximum adsorption was obtained at pH 1.0 for all dyes due to available anionic groups attached to the structures, which can be justified by pH{sub pzc} 6.7 for the biosorbent BCM. The ability of babassu coconut mesocarp to adsorb dyes gave the order R S2G > VR 5 > BR 160 > IOG > RR 5, which data were best fit to Freundlich model, but did not well-adjusted for all dyes. The dye/biopolymer interactions at the solid/liquid interface are all spontaneous as given by free Gibbs energy, with exothermic enthalpic values of -26.1, -15.8, -17.8, -15.8 and -23.7 kJ mol{sup -1} for BR 160, R S2G, RR 5, IOG and VR 5, respectively. In spite of the negative entropic values contribution, the set of thermodynamic data is favorable for all dyes removal. However, the results pointed to the effectiveness of the mesocarp of babassu coconut as a biosorbent for removing textile dyes from aqueous solutions.

  10. Kinetics and thermodynamics of textile dye adsorption from aqueous solutions using babassu coconut mesocarp

    International Nuclear Information System (INIS)

    Extracted babassu coconut (Orbignya speciosa) mesocarp (BCM) was applied as a biosorbent for aqueous Blue Remazol R160 (BR 160), Rubi S2G (R S2G), Red Remazol 5R (RR 5), Violet Remazol 5R (VR 5) and Indanthrene Olive Green (IOG) dye solutions. The natural sorbent was processed batchwise while varying several system parameters such as stirring time, pH and temperature. The interactions were assayed with respect to both pseudo-first-order and second-order reaction kinetics, with the latter the more suitable kinetic model. The maximum adsorption was obtained at pH 1.0 for all dyes due to available anionic groups attached to the structures, which can be justified by pHpzc 6.7 for the biosorbent BCM. The ability of babassu coconut mesocarp to adsorb dyes gave the order R S2G > VR 5 > BR 160 > IOG > RR 5, which data were best fit to Freundlich model, but did not well-adjusted for all dyes. The dye/biopolymer interactions at the solid/liquid interface are all spontaneous as given by free Gibbs energy, with exothermic enthalpic values of -26.1, -15.8, -17.8, -15.8 and -23.7 kJ mol-1 for BR 160, R S2G, RR 5, IOG and VR 5, respectively. In spite of the negative entropic values contribution, the set of thermodynamic data is favorable for all dyes removal. However, the results pointed to the effectiveness of the mesocarp of babassu coconut as a biosorbent for removing textile dyes from aqueous solutions.

  11. Thermodynamics

    CERN Document Server

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    Shvab, I.; Sadus, Richard J., E-mail: rsadus@swin.edu.au [Centre for Molecular Simulation, Swinburne University of Technology, PO Box 218 Hawthorn, Victoria 3122 (Australia)

    2014-03-14

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

  13. Magnetic properties and thermodynamics in a metallic nanotube

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Wei, E-mail: weijiang.sut.edu@gmail.com; Li, Xiao-Xi; Guo, An-Bang; Guan, Hong-Yu; Wang, Zan; Wang, Kai

    2014-04-15

    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.

  14. Prediction of thermodynamic properties of refrigerants using data mining

    International Nuclear Information System (INIS)

    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.

  15. Thermodynamic properties of stable and metastable phases of Pt metal

    Institute of Scientific and Technical Information of China (English)

    PENG Hong-jian; XIE You-qing; NIE Yao-zhuang

    2009-01-01

    Isometric heat capacity cv and isobaric heat capacity cp of Pt with stable and metastable phases were calculated by using pure element systematic theory. These results are in excellent agreement with of SGTE (Scientific Group Thermodata Europe) database and JANAF (Joint Army-Navy-Air Force) experimental values. The calculation results of cv and cp of Pt metal in natural state are in good agreement with those calculated by FP(first-principles) method. It is found that the electron devotion to heat capacity is important to adjust in OA(one-atom) method while calculating heat capacity. The full information about thermodynamic properties of Pt metal with stable and metastable phases, such as entropy(S), enthalpy(H) and Gibbs energy(G) were calculated from 0 K to random temperature. The results are in good agreement with JANAF experimental value. In contrast to SGTE database, the thermodynamic properties from 0 K to 298.15 K are implemented.

  16. Thermodynamic Property Models for Unburned Mixtures and Combustion Gases

    OpenAIRE

    Rosario, Lanzafame; Michele, Messina

    2006-01-01

    New mathematical functions, with the functional form of a fifth order logarithmic polynomial, have been developed. These polynomials have been used to describe gases’ thermodynamic properties, and have been utilized for combustion processes, with “frozen composition” and “shifting equilibrium composition” evaluation. The logarithmic polynomials present the advantage of covering a wide range of temperatures with only a single mathematical function. The logarithmic...

  17. Quantum Modeling of Thermodynamic Properties of Warm Dense Aluminum

    OpenAIRE

    Termini, Nicholas; Miloshesky, Gennady; Hassanein, Ahmed

    2015-01-01

    Warm dense matter is attracting a lot of attention in the scientific community, due to its formation during intense laser-matter interaction and inertial confinement fusion. However, there is no accurate solution to mapping out the thermodynamic properties of warm dense matter. Experimental data are also incredibly scarce making computational models an incredibly useful tool. This paper provides equation of state (EOS) data for aluminum at specific densities within the warm dense matter regim...

  18. On thermodynamic properties of heavy fermion systems in magnetic field

    International Nuclear Information System (INIS)

    Using a two-conduction-band Anderson lattice model, the influence of magnetic field on thermodynamic properties of the heavy fermion systems is studied by means of the slave boson mean-field theory. The depression of the heavy fermion state by magnetic field is found. A theoretical explanation to the anomalous volume magneto-striction of heavy fermion systems is also given in this paper. (author). 27 ref, 5 figs

  19. Prediction of thermodynamic properties of actinide and lanthanide compounds

    Institute of Scientific and Technical Information of China (English)

    LU Chunhai; NI Shijun; SUN Ying; CHEN Wenkai; ZHANG Chengjiang

    2008-01-01

    Several relationship models for thermodynamic functions of actinide and lanthanide compounds are built. The descriptors such as the difference of atomic radii between metal atoms and nonmetal atoms and the molecular mass are used in quantitative structure-activity/property relationships. The relative errors for entropy and heat capacity are less than 20% in the majority of gaseous compounds. Similar results are obtained from solid compounds.

  20. Adsorption removal of Congo red from aqueous solution by polyhedral Cu2O nanoparticles: Kinetics, isotherms, thermodynamics and mechanism analysis

    International Nuclear Information System (INIS)

    Highlights: • Polyhedral Cu2O NPs with rough surfaces were prepared by a one-pot sonochemical precipitation method. • The Cu2O NPs show unprecedented adsorption capability toward Congo red. • CR adsorption onto Cu2O is a spontaneous, endothermic and chemisorption process. • The Cu2O adsorbent can be photocatalytically regenerated by visible light irradiation. - Abstract: Polyhedral cuprous oxide nanoparticles (Cu2O NPs) with rough surfaces were prepared by a one-pot sonochemical precipitation method. The products were characterized by SEM, XRD, EDS, XPS, and UV–Vis DRS, respectively. The adsorption behavior of Congo red (CR) from aqueous solution onto the as-prepared Cu2O NPs was systematically investigated. The equilibrium and kinetic studies suggested that the adsorption process followed Freundlich isotherm and pseudo-second order model, respectively. The as-prepared Cu2O NPs exhibited remarkable adsorption properties toward CR. The maximum adsorption capacity at 20 °C was 3904 mg g−1, which was the highest reported value so far in adsorption removal of CR. Together with the evaluation of the thermodynamic parameters such as Gibbs free energy, enthalpy and entropy change, our results show that the adsorption of CR onto Cu2O is a spontaneous, endothermic and chemisorption process. A putative interaction model between CR and Cu2O NPs was proposed. Moreover, the Cu2O adsorbent could be photocatalytically regenerated and reused without significant loss of its adsorption capability

  1. Determination of thermodynamic parameters of Cr(VI) adsorption from aqueous solution onto Agave lechuguilla biomass

    Energy Technology Data Exchange (ETDEWEB)

    Romero-Gonzalez, J. [Environmental Science and Engineering, University of Texas at El Paso, El Paso, TX 79968 (United States); Peralta-Videa, J.R. [Department of Chemistry, University of Texas at El Paso, El Paso, TX 79968 (United States); Rodriguez, E. [Environmental Science and Engineering, University of Texas at El Paso, El Paso, TX 79968 (United States); Ramirez, S.L. [Department of Chemistry, University of Texas at El Paso, El Paso, TX 79968 (United States); Gardea-Torresdey, J.L. [Environmental Science and Engineering, University of Texas at El Paso, El Paso, TX 79968 (United States) and Department of Chemistry, University of Texas at El Paso, El Paso, TX 79968 (United States)]. E-mail: jgardea@utep.edu

    2005-04-15

    The temperature dependence of the Cr(VI) bioadsorption and its possible reduction to Cr(III) by Agave lechuguilla biomass were studied. The experimental data obtained in batch experiments at different temperatures were fitted to the Langmuir and Freundlich isotherms to obtain the characteristic parameters of each model. The adsorption equilibrium data fitted well with the Freundlich model. The average model parameters calculated from Freundlich's isotherms (adsorption capacity K{sub F} = 4 . 10{sup -2} mol . g{sup -1} and an average adsorption intensity value n = 13.07) showed that A. lechuguilla can be considered as an effective biomaterial for Cr(VI) removal from aqueous solution. Thermodynamic parameters ({delta}G{sup .}, {delta}H{sup .}, and {delta}S{sup .}) for Cr(VI) adsorption determined in the temperature range from (283 to 313) K suggest that a portion of Cr(VI) may be bound to functional groups on the surface of the adsorbent and then reduced to Cr(III). Additionally, the parameters of the Dubinin-Radushkevick equation indicated that the sorption of chromium species onto lechuguilla biomass mainly proceeds through binding surface functional groups.

  2. Association of ionic liquids with cationic dyes in aqueous solution: A thermodynamic study

    International Nuclear Information System (INIS)

    Highlights: ► Precipitate was formed between cationic dye and ionic liquid in aqueous solution. ► Precipitates are 1:1 formed by cation of the dyes and anion of the ionic liquids. ► Association constants decrease with increasing temperature. ► The associates can be used as active materials of ion-selective electrode. - Abstract: In this paper, the interactions between cationic dyes and the ionic liquids (ILs) have been studied by 31P nuclear magnetic resonance (NMR), UV–Vis spectroscopy and conductometric measurements at different temperatures. It was shown that a decrease in the measured specific conductance of the (dye + IL) mixtures was caused by the formation of non-conducting or less conducting (dye + IL) associates. The associates were formed by 1:1 ratio of cation of the cationic dyes and anion of the ILs by using the 31P NMR and UV–Vis spectroscopy methods. The association constants were calculated by theoretical model based on the deviation from linear behavior, and the association constants were as high as 106 (L · mol−1)2. Thermodynamic results imply that the formation process of association was exothermic nature. It is expected that the associates reported here would have promising application as active materials for the preparation of ion-selective electrode used in the determination of ILs concentrations.

  3. Determination of thermodynamic parameters of Cr(VI) adsorption from aqueous solution onto Agave lechuguilla biomass

    International Nuclear Information System (INIS)

    The temperature dependence of the Cr(VI) bioadsorption and its possible reduction to Cr(III) by Agave lechuguilla biomass were studied. The experimental data obtained in batch experiments at different temperatures were fitted to the Langmuir and Freundlich isotherms to obtain the characteristic parameters of each model. The adsorption equilibrium data fitted well with the Freundlich model. The average model parameters calculated from Freundlich's isotherms (adsorption capacity KF = 4 . 10-2 mol . g-1 and an average adsorption intensity value n = 13.07) showed that A. lechuguilla can be considered as an effective biomaterial for Cr(VI) removal from aqueous solution. Thermodynamic parameters (ΔG., ΔH., and ΔS.) for Cr(VI) adsorption determined in the temperature range from (283 to 313) K suggest that a portion of Cr(VI) may be bound to functional groups on the surface of the adsorbent and then reduced to Cr(III). Additionally, the parameters of the Dubinin-Radushkevick equation indicated that the sorption of chromium species onto lechuguilla biomass mainly proceeds through binding surface functional groups

  4. Solubility of drugs in aqueous solutions. Part 5. Thermodynamic consistency test for the solubility data.

    Science.gov (United States)

    Ruckenstein, E; Shulgin, I

    2005-03-23

    This paper is devoted to the verification of the quality of experimental data regarding the solubility of sparingly soluble solids, such as drugs, environmentally important substances, etc. in mixed solvents. A thermodynamic consistency test based on the Gibbs-Duhem equation for ternary mixtures is suggested. This test has the form of an equation, which connects the solubilities of the solid, and the activity coefficients of the constituents of the solute-free mixed solvent in two mixed solvents of close compositions. The experimental data regarding the solubility of sparingly soluble substances can be verified with the suggested test if accurate data for the activity coefficients of the constituents of the solute-free mixed solvent are available. The test was applied to a number of systems representing the solubilities of sparingly soluble substances in mixed solvents. First, the test was scrutinized for four nonaqueous systems for which accurate solubility data were available. Second, the suggested test was applied to a number of systems representing experimental data regarding the solubility of sparingly soluble substances in aqueous mixed solvents. PMID:15725556

  5. Chromium Biosorption from Cr(VI) Aqueous Solutions by Cupressus lusitanica Bark: Kinetics, Equilibrium and Thermodynamic Studies

    OpenAIRE

    Alma Rosa Netzahuatl-Muñoz; María del Carmen Cristiani-Urbina; Eliseo Cristiani-Urbina

    2015-01-01

    The present study investigated the kinetics, equilibrium and thermodynamics of chromium (Cr) ion biosorption from Cr(VI) aqueous solutions by Cupressus lusitanica bark (CLB). CLB total Cr biosorption capacity strongly depended on operating variables such as initial Cr(VI) concentration and contact time: as these variables rose, total Cr biosorption capacity increased significantly. Total Cr biosorption rate also increased with rising solution temperature. The pseudo-second-order model describ...

  6. Mixed 2D molecular systems: Mechanic, thermodynamic and dielectric properties

    Science.gov (United States)

    Beňo, Juraj; Weis, Martin; Dobročka, Edmund; Haško, Daniel

    2008-08-01

    Study of Langmuir monolayers consisting of stearic acid (SA) and dipalmitoylphosphatidylcholine (DPPC) molecules was done by surface pressure-area isotherms ( π- 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 π- 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.

  7. Mixed 2D molecular systems: Mechanic, thermodynamic and dielectric properties

    International Nuclear Information System (INIS)

    Study of Langmuir monolayers consisting of stearic acid (SA) and dipalmitoylphosphatidylcholine (DPPC) molecules was done by surface pressure-area isotherms (π-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 π-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

  8. Thermodynamic properties of magnetic strings on a square lattice

    Science.gov (United States)

    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.

  9. The VLab repository of thermodynamics and thermoelastic properties of minerals

    Science.gov (United States)

    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.

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

    International Nuclear Information System (INIS)

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

  11. Thermodynamic properties of average-atom interatomic potentials for alloys

    Science.gov (United States)

    Nöhring, Wolfram Georg; Curtin, William Arthur

    2016-05-01

    The atomistic mechanisms of deformation in multicomponent random alloys are challenging to model because of their extensive structural and compositional disorder. For embedded-atom-method interatomic potentials, a formal averaging procedure can generate an average-atom EAM potential and this average-atom potential has recently been shown to accurately predict many zero-temperature properties of the true random alloy. Here, the finite-temperature thermodynamic properties of the average-atom potential are investigated to determine if the average-atom potential can represent the true random alloy Helmholtz free energy as well as important finite-temperature properties. Using a thermodynamic integration approach, the average-atom system is found to have an entropy difference of at most 0.05 k B/atom relative to the true random alloy over a wide temperature range, as demonstrated on FeNiCr and Ni85Al15 model alloys. Lattice constants, and thus thermal expansion, and elastic constants are also well-predicted (within a few percent) by the average-atom potential over a wide temperature range. The largest differences between the average atom and true random alloy are found in the zero temperature properties, which reflect the role of local structural disorder in the true random alloy. Thus, the average-atom potential is a valuable strategy for modeling alloys at finite temperatures.

  12. Thermodynamic Properties of Organometallic Dihydrogen Complexes for Hydrogen Storage Applications

    Science.gov (United States)

    Abrecht, David Gregory

    The mechanism and thermodynamic properties of hydrogen binding to the solid-state complexes [M(CO)dppe2][BArF24] (M = Mn, Re, Tc) and [M'Hdppe2][NTf2] (M' = Fe, Ru, Os) were investigated experimentally and computationally over the temperature range 298K-373K and pressure range 0-2800 torr, based on the Sieverts method. The bulk absorption behavior was found to be accurately described by Langmuir isotherms. Enthalpy and entropy values of ΔH° = -52.2 kJ/mol and ΔS° = -99.6 J/mol-K were obtained experimentally for hydrogen absorption onto [Mn(CO)dppe2][BArF24] from the Langmuir equilibrium constant, and values obtained from electronic structure calculations using the LANL2DZ-ECP basis set were found to successfully reproduce both the pressure-temperature-composition behavior and the thermodynamic values to within 5% of those obtained through experiment. Results from simulations for all complexes yielded large enthalpy values similar to metal hydride formation enthalpies for all complexes studied, and the substitution of the metal center reproduced qualitative binding strength trends of 5d>3d>4d consistent with those previously reported for the group 6 metals. X-ray diffraction patterns and Mössbauer spectra were taken to determine the thermal decomposition pathway for [FeH(η2-H 2)dppe2][NTf2]. Simulations at the B3LYP/TZVP level of theory and experimental Mössbauer spectra confirmed the direct thermal decomposition from singlet-state [FeH(η2-H 2)dppe2][NTf2] to triplet-state [FeHdppe 2][NTf2] under vacuum conditions at 398K. Evaluation of the partial quadrupole splitting values of Q(H2) = -0.245 mm/s from Mössbauer spectroscopy significantly differ from typical values obtained for hydrides, indicating an underutilized mechanism for identification of dihydrogen ligands. Singlet-state thermodynamic values from simulation were consistent with experimental observations for Ru and Os, and ruthenium complexes were found to have thermodynamic properties within

  13. NIR Spectroscopic Properties of Aqueous Acids Solutions

    Directory of Open Access Journals (Sweden)

    Mohd Zubir MatJafri

    2012-06-01

    Full Text Available Acid content is one of the important quality attributes in determining the maturity index of agricultural product, particularly fruits. Despite the fact that much research on the measurement of acidity in fruits through non-destructive spectroscopy analysis at NIR wavelengths between 700 to 1,000 nm has been conducted, the same response towards individual acids is not well known. This paper presents NIR spectroscopy analysis on aqueous citric, tartaric, malic and oxalic solutions through quantitative analysis by selecting a set of wavelengths that can best be used to measure the pH of the solutions. The aquaphotomics study of the acid solutions has generated R2 above 0.9 for the measurement of all acids. The most important wavelengths for pH are located at 918–925 nm and 990–996 nm, while at 975 nm for water.

  14. Adsorption of arsenic from aqueous media using lateritic minerals. Equilibrium, kinetic and thermodynamic studies

    Energy Technology Data Exchange (ETDEWEB)

    Khalid, Nasir; Daud, Muhammad [Pakistan Institute of Nuclear Science and Technology, Islamabad (Pakistan). Chemistry Div.

    2014-07-01

    The sorption behavior of arsenic on minerals from a lateritic weathering has been investigated to evaluate its potential for the decontamination of arsenic ions from aqueous media. Various physicochemical parameters such as pH, equilibration time, adsorbent dose, concentration of adsorbate, effect of diverse ions and temperature were studied in order to simulate the best conditions under which this material can be used as an adsorbent, employing batch method and radiotracer technique. Maximum adsorption was observed in buffer solutions having pH of 2.0 and 8-9, using 0.5 g of adsorbent for 6.674 x 10{sup -5} mol L{sup -1} arsenic concentration in 10 min equilibration time. The sorption data followed the pseudo-second order reaction kinetics. The adsorption data fit both the Freundlich and Dubinin-Radushkevich isotherm equations over the range of 3.195 x 10{sup -5} to 3.195 x 10{sup -3} mol L{sup -1} arsenic concentration. The characteristic Freundlich constants i.e. 1/n = 0.427 ± 0.009 and K = 3.04 x 10{sup -4} ± 1.46 x 10{sup -5} mol g{sup -1} have been computed for the sorption system. The sorption mean free energy from the Dubinin-Radushkevich isotherm is 12.00 ± 0.38 kJ mol{sup -1} indicating ion-exchange mechanism of chemisorption. The uptake of arsenic increases with the rise in temperature (278.16-323.16 K). Thermodynamic quantities i.e.ΔG, ΔS and ΔH have also been calculated for the system. The sorption process was found to be endothermic. (orig.)

  15. Adsorption kinetics and thermodynamics of Malachite Green from aqueous solutions onto expanded Graphite nanosheets

    Directory of Open Access Journals (Sweden)

    Gh. Kiani

    2015-01-01

    Full Text Available Expanded graphite nanosheets (EG-nanosheets were used for adsorption of Malachite Green (MG from aqueous solution. The influences of dye concentrations, absorbent dosage, pH values and the temperatures on the adsorption were investigated as well. The dye adsorption experiments were carried out by utilizing batch procedure. EG-nanosheets were initially characterized by scanning electron microscopy (SEM, fourier transform infrared (FT-IR and X-ray diffraction (XRD. Adsorption efficiency increased with increment in initial pH, dye con­centration and temperature, but decreased with increment in adsorbent dose. The rate parameters of adsorption were evaluated by First-order, pseudo-second-order, and intraparticle diffusion models. These data indicated an endothermic spontaneous adsorption process and kinetically followed the pseudo-second order model with activation energy of +17.44 kJmol-1. Langmuir, Freundlich and Temkin equations were used for analyzing of experimental isotherm data and found that the Langmuir isotherm model showed good fit to the equilibrium adsorption data. The maximum adsorption capacity of 158.9 mg g-1 of Malachite Green was achieved (dye initial concentration of 100 mg L-1. Thermodynamic parameters such as changes in the free energy of adsorption (ΔG°, enthalpy (ΔH° and entropy (ΔS° were calculated. The negative values of ΔG° indicate that the malachite green adsorption process is spontaneous in nature and the positive value of ΔH° shows the endothermic nature of the process. Adsorption onto EG has proved to be highly efficient technique for the handling of dye-contaminated waters.

  16. Thermodynamic study of the adsorption of chromium ions from aqueous solution on waste corn cobs material

    Directory of Open Access Journals (Sweden)

    Rafael A. Fonseca-Correa

    2014-12-01

    Full Text Available The paper shows the results of a study obtaining activated carbon from corn cobs and determining its use as an adsorbent for the removal of Cr3+ from aqueous solutions. The finely ground precursor was subjected to pyrolysis at 600 and 900 °C in a nitrogen atmosphere and chemical activation with H2O2 and HNO3. The effects of pyrolysis conditions and activation method on the physicochemical properties of the materials obtained were tested. The samples were characterised chemically and texturally. Were obtained microporous activated carbons of well-developed surface area varying from 337 to 1213 m2/g and exhibited differences acid-base character of the surface. The results obtained shows that a suitable good option of the activation procedure for corncobs permits the production of economic adsorbents with high sorption capacity for Cr3+ from aqueous solutions. A detailed study of immersion calorimetry was performed with carbons prepared from corn cobs to establish possible relationships with these materials between the enthalpies of immersion and textural and chemical parameters.

  17. Molecular structure and thermodynamic properties of scandium halides

    International Nuclear Information System (INIS)

    Experimental data on molecular constants of mono-, di- and trihalides of scandium, as well as di-scandium hexahalides of the composition ScXn and Sc2X6 (X = F - I; n = 1 - 3), have been analyzed. Specific features of the compounds molecule structure are considered. The values of molecular constants have been evaluated by the methods of statistical thermodynamics and thermodynamic properties of all scandium halides mentioned in the temperature range of 100 - 6000 K and 298.15 - 1000 K respectively for scandium monohalides and for di-, tri-, hexahalides have been calculated. The values of thermodynamic functions Cp Deg, Φ Deg (T), H Deg (T) - H Deg (0) at 298.15 K published for the first time equal respectively for ScF: 32.734; 192.186; 222.232; 8.958; for ScCl: 45.782; 203.351; 237.356; 10.138; for ScBr: 49.449; 215.090; 252.783; 11.238; for ScI: 42.605; 227.517; 265.635; 12.259

  18. Thermodynamic properties of 5-(1-adamantyl)tetrazole

    International Nuclear Information System (INIS)

    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

  19. 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.

  20. Transport anb Structural Properties of Aqueous Solutions of Organic Solvents.

    OpenAIRE

    Nieto Draghi, Carlos Eduardo

    2003-01-01

    Molecular Dynamics simulation technique has been used in this work to obtain equilibrium as well as transport properties of different aqueoussolutions. The peculiar behavior observed in pure water and its mixtures with other substances at different thermodynamic conditions, and the knowledge and understanding of the properties of these systems are the motivations of this work. We have made a direct connection between the local tetrahedral structure of water, created by the presence of hydroge...

  1. 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.

  2. Thermodynamic properties of Ni-Al-Cr melts

    International Nuclear Information System (INIS)

    Thermodynamic properties of binary boundary systems and five sections of a Ni-Al-Cr ternary system, one of which being a quasibinary (NiAl)-Cr system, are studied using a calorimetric method under isoperibolic conditions at 1870-1960 K. It is revealed that interparticle interaction of unlike atoms is typical for Ni-Al-Cr melts. A mixing heat minimum falls on an equiatomic alloy of a binary boundary Ni-Al system. A solid solution on the basis of congruous melting thermally stable nickel monoaluminide is formed in the alloy according to a state diagram

  3. Spectroscopic and thermodynamic properties of L-ornithine monohydrochloride

    International Nuclear Information System (INIS)

    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

  4. Lattice dielectric and thermodynamic properties of yttria stabilized zirconia solids

    Energy Technology Data Exchange (ETDEWEB)

    Lau, Kah Chun [Department of Chemistry, George Washington University, Washington, DC 20052 (United States); Dunlap, Brett I [Naval Research Laboratory, Code 6189, Washington, DC 20375 (United States)], E-mail: kah.lau.ctr.my@nrl.navy.mil

    2009-04-08

    A study of lattice dielectric and thermodynamic properties of yttria stabilized zirconia (YSZ) crystals as a function of yttria concentration is reported. This study is based on density functional perturbation theory, using ABINIT. Within the local density approximation and the harmonic approximation, we find excellent agreement between calculated and low temperature experimental specific heat and dielectric constants. From the variation of the specific heat of YSZ with the yttria composition, we propose a simple additivity rule that estimates the dependence of the specific heat of YSZ on the yttria concentration, whereas for the dielectric constants of YSZ, the values are bounded by the dielectric constants of cubic and amorphous zirconia.

  5. A method for determining thermophysical properties of organic material in aqueous solutions: Succinic acid

    Science.gov (United States)

    Riipinen, I.; Svenningsson, B.; Bilde, M.; Gaman, A.; Lehtinen, K. E. J.; Kulmala, M.

    2006-12-01

    A method for determining evaporation rates and thermodynamic properties of aqueous solution droplets is introduced. The method combines evaporation rate measurements using modified TDMA technique with data evaluation using an accurate evaporation model. The first set of data has been collected and evaluated for succinic acid aqueous solution droplets. Evaporation rates of succinic acid solution droplets have been measured using a TDMA system at controlled relative humidity (65%) and temperature (298 K). A temperature-dependent expression for the saturation vapour pressure of pure liquid phase succinic acid at atmospheric temperatures has been derived by analysing the evaporation rate data with a numerical model. The obtained saturation vapour pressure of liquid phase succinic acid is ln( p) = 118.41 - 16204.8/ T - 12.452ln( T). The vapour pressure is in unit of Pascal and the temperature in Kelvin. A linear expression for the enthalpy of vaporization for liquid state succinic acid is also presented. According to the results presented in the following, a literature expression for the vapour pressure of liquid phase succinic acid defined for temperatures higher than 461 K [Yaws, C.L., 2003. Yaws' Handbook of Thermodynamic and Physical Properties of Chemical Compounds, Knovel] can be extrapolated to atmospheric temperatures with very good accuracy. The results also suggest that at 298 K the mass accommodation coefficient of succinic acid is unity or very close to unity.

  6. Thermodynamic properties of xanthone: Heat capacities, phase-transition properties, and thermodynamic-consistency analyses using computational results

    International Nuclear Information System (INIS)

    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

  7. Thermodynamic Study on the Protonation Reactions of Glyphosate in Aqueous Solution: Potentiometry, Calorimetry and NMR spectroscopy.

    Science.gov (United States)

    Liu, Bijun; Dong, Lan; Yu, Qianhong; Li, Xingliang; Wu, Fengchang; Tan, Zhaoyi; Luo, Shunzhong

    2016-03-10

    Glyphosate [N-(phosphonomethyl)glycine] has been described as the ideal herbicide because of its unique properties. There is some conflicting information concerning the structures and conformations involved in the protonation process of glyphosate. Protonation may influence the chemical and physical properties of glyphosate, modifying its structure and the chemical processes in which it is involved. To better understand the species in solution associated with changes in pH, thermodynamic study (potentiometry, calorimetry and NMR spectroscopy) about the protonation pathway of glyphosate is performed. Experimental results confirmed that the order of successive protonation sites of totally deprotonated glyphosate is phosphonate oxygen, amino nitrogen, and finally carboxylate oxygen. This trend is in agreement with the most recent theoretical work in the literature on the subject ( J. Phys. Chem. A 2015, , 119 , 5241 - 5249 ). The result is important because it confirms that the protonated site of glyphosate in pH range 7-8, is not on the amino but on the phosphonate group instead. This corrected information can improve the understanding of the glyphosate chemical and biochemical action. PMID:26862689

  8. Thermodynamic properties of water in compacted sodium montmorillonite

    International Nuclear Information System (INIS)

    Compacted bentonite is a promising material as an engineering barrier to enclose nuclear waste. The migration of nuclides occurs in the water of bentonite, where the major mineral is sodium montmorillonite. To determine the thermodynamic properties of water in compacted sodium montmorillonite, the equilibrium vapor pressure of the water in the montmorillonite was measured as a function of water content and temperature, without external pressure. The thermodynamic properties depend on water content but not on the dry density of unsaturated specimens. In montmorillonite, single-layer adsorption may proceed from 0 to 16 wt% water content, two-layer adsorption from 16 to 27 wt%, and three-layer adsorption above 27 wt%; pore water appears only in the last region. It is probable that 30 wt% of the total water included in saturated montmorillonite is not in the interlayer between platelets at 45.0 wt% water content and 0.80 x 103 kg/m3 dry density. There is a very slight amount of water, which is not bound between platelets at dry densities of 1.20 and 1.76 x 103 kg/m3. This water is not a dilute electrolytic solution but has higher ionic strength, like typical seawater of salinity 23 per-thousand and saturated NaCl

  9. Structural, elastic and thermodynamic properties of Ti2SC

    Indian Academy of Sciences (India)

    Hongzhi Fu; Wenfang Liu; Tao Gao

    2011-12-01

    The structural parameters, elastic constants and thermodynamic properties of Ti2SC were investigated under pressure and temperature by using first-principles plane-wave pseudopotential density functional theory within the generalized gradient approximation. The obtained results are in agreement with the available experimental data. The bulk moduli along the - and -axes, $B_{a}$ and $B_{c}$, almost linearly increase with pressure, and the former is always smaller than the latter. The ratio of $B_{c}/B_{a}$ has a trend of gradual increase as the pressure increases. It is found that the elastic constants, anisotropy and Debye temperature of Ti2SC increase with pressure, while axial compressibility along the - and -axes decreases with pressure. The thermal properties including the equation of state, the Grüneisen parameter , the anisotropies $\\Delta_{p}, \\Delta_{S1}$ and $\\Delta_{S2}$, and the heat capacity are estimated at various pressures and temperatures.

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

    Science.gov (United States)

    Fessler, T. E.

    1994-01-01

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

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

    Science.gov (United States)

    Fessler, T. E.

    1994-01-01

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

  12. Thermodynamic studies on the interaction between some amino acids with some rare earth metal ions in aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Mohamed, AbdAllah A.; Bakr, Moustafa F.; Abd El-Fattah, Khaled A

    2003-11-06

    The interactions between the amino acids (glycine and L-threonine) with some rare earth metal ions (Pr{sup 3+}, Nd{sup 3+}, Eu{sup 3+}, Gd{sup 3+}, Dy{sup 3+}, Ho{sup 3+} and Yb{sup 3+}) were studied at a wide range from ionic strengths (0.07-0.32 M KNO{sub 3}) and temperatures (25-45 deg. C) in aqueous solutions by using Bjerrum potentiometric method. The stoichiometric and thermodynamic stability constants were calculated as well as the standard thermodynamic parameters ({delta}G deg., {delta}H deg. and {delta}S deg. ) for all possible reactions that occur. The degree of formation (n-bar) for all studied systems was determined and discussed. The thermodynamic parameters differences ({delta}{delta}G deg., {delta}{delta}H deg. and {delta}{delta}S deg. ) were calculated and discussed to determine the factors which control these complexation processes from the thermodynamic point of view.

  13. Polymorph selection and nanocrystallite rearrangement of calcium carbonate in carboxymethyl chitosan aqueous solution: Thermodynamic and kinetic analysis

    International Nuclear Information System (INIS)

    In this article, the polymorph selection of calcium carbonate has been successfully achieved in water-soluble carboxymethyl chitosan aqueous solution at different temperatures (25-95 oC). Vaterite is formed in carboxymethyl chitosan solution 25 oC accompanied with trace of calcite, whereas pure aragonite is obtained at 95 oC. Scanning electron microscopy and transmission electron microscopy analyses show that the products are formed from the recrystallization of nanometer crystallites. Thermodynamic and kinetic analyses reveal that the polymorph of calcium carbonate is controlled and selected by kinetics in various temperatures. As a heterogeneous nucleator and stabilizing agent, carboxymethyl chitosan changes the nucleation and growth of calcium carbonate from thermodynamic into kinetic control. Under kinetic limitation, the reaction rate of aragonite increases along with the elevating of temperature and surpasses the rate of vaterite above 327 K.

  14. Polymorph selection and nanocrystallite rearrangement of calcium carbonate in carboxymethyl chitosan aqueous solution: Thermodynamic and kinetic analysis

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Donghui [Key Lab For Special Functional Materials Ministry of Education, Henan University, Kaifeng 475004 (China); Key Lab of Inorganic Coating Materials, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi, Changning, Shanghai 200050 (China); Zhu, Yingchun, E-mail: yzhu@mail.sic.ac.cn [Key Lab of Inorganic Coating Materials, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi, Changning, Shanghai 200050 (China); Li, Fang; Ruan, Qichao [Key Lab of Inorganic Coating Materials, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi, Changning, Shanghai 200050 (China); Zhang, Shengmao [Key Lab For Special Functional Materials Ministry of Education, Henan University, Kaifeng 475004 (China); Zhang, Linlin; Xu, Fangfang [Key Lab of Inorganic Coating Materials, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi, Changning, Shanghai 200050 (China)

    2010-01-15

    In this article, the polymorph selection of calcium carbonate has been successfully achieved in water-soluble carboxymethyl chitosan aqueous solution at different temperatures (25-95 {sup o}C). Vaterite is formed in carboxymethyl chitosan solution 25 {sup o}C accompanied with trace of calcite, whereas pure aragonite is obtained at 95 {sup o}C. Scanning electron microscopy and transmission electron microscopy analyses show that the products are formed from the recrystallization of nanometer crystallites. Thermodynamic and kinetic analyses reveal that the polymorph of calcium carbonate is controlled and selected by kinetics in various temperatures. As a heterogeneous nucleator and stabilizing agent, carboxymethyl chitosan changes the nucleation and growth of calcium carbonate from thermodynamic into kinetic control. Under kinetic limitation, the reaction rate of aragonite increases along with the elevating of temperature and surpasses the rate of vaterite above 327 K.

  15. Thermodynamic Properties of 1:1 Salt Aqueous Solutions with the Electrolattice Equation of State Propriétés thermophysiques des solutions aqueuses de sels 1:1 avec l’équation d’état de réseau pour électrolytes

    Directory of Open Access Journals (Sweden)

    Zuber A.

    2013-05-01

    Full Text Available The electrolattice Equation of State (EOS is a model that extends the MattediTavares-Castier EOS (MTC EOS to systems with electrolytes. This model considers the effect of three terms. The first one is based on a lattice-hole model that considers local composition effects derived in the context of the generalized Van der Waals theory: the MTC EOS was chosen for this term. The second and the third terms are the Born and the MSA contributions, which take into account ion charging and discharging and long-range ionic interactions, respectively. Depending only on two energy interaction parameters, the model represents satisfactorily the vapor pressure and the mean ionic activity coefficient data of single aqueous solutions containing LiCI, LiBr, LiI, NaCl, NaBr, NaI, KCl, KBr, KI, CsCl, CsBr, CsI, or RbCI. Two methods are presented and contrasted: the salt-specific and the ion-specific approaches. Therefore, the aim of this work is to calculate thermodynamic properties that are extensively used to design, operate and optimize many industrial processes, including water desalination. L’équation d’état, dite électrolattice, est un modèle qui étend l’équation d’état de Mattedi-Tavares-Castier à des systèmes avec électrolytes. Ce modèle prend en compte l’effet de trois termes. Le premier terme est basé sur les trous dans le réseau en considérant les effets de la composition locale, étude effectuée dans le cadre de la théorie généralisée de Van der Waals : l’équation d’état de Mattedi-Tavares-Castier a été choisie pour ce premier terme. Les deuxième et troisième termes sont les contributions de Born et du MSA. Ils tiennent compte du chargement et du déchargement des ions, et des interactions ioniques à longue distance, respectivement. Le modèle n’ayant besoin que de deux paramètres d’interaction énergétique, il modélise de manière satisfaisante la pression de vapeur et le coefficient d’activité ionique

  16. Antiscalant properties of Spergularia rubra and Parietaria officinalis aqueous solutions

    Science.gov (United States)

    Cheap-Charpentier, Hélène; Gelus, Dominique; Pécoul, Nathalie; Perrot, Hubert; Lédion, Jean; Horner, Olivier; Sadoun, Jonathan; Cachet, Xavier; Litaudon, Marc; Roussi, Fanny

    2016-06-01

    The formation of calcium carbonate in water has important implications in industry. Chemical antiscalant is usually used to control scale depositions. Plant extracts have been recently used as new green antiscalant agents, as they can be easily prepared and are environmentally friendly. In this study, stock aqueous solutions of Spergularia rubra and Parietaria officinalis, two plants used in traditional medicine to treat or prevent urolithiasis, were obtained by infusion. The antiscaling properties of these extracts towards CaCO3 formation were tested by using chronoamperometry and Fast Controlled Precipitation methods. The aqueous solution of S. rubra was further fractionated to isolate compounds of lower polarity. Their efficiency towards CaCO3 precipitation was characterized by Fast Controlled Precipitation method. The inhibiting efficiency of this fractionated solution was greater than that of the stock aqueous solution.

  17. Formulation of thermodynamic properties for computation of non-equilibrium condensing steam flows

    Czech Academy of Sciences Publication Activity Database

    Hrubý, Jan

    Londýn: British & Irish Association for Properties of Water and Steam (BIAPWS) a Institution of Mechanical Engineers, 2013, PWS-30. [International Conference on the Properties of Water and Steam /16./ ICPWS. University of Greenwich, Londýn (GB), 01.09.2013-05.09.2013] Institutional support: RVO:61388998 Keywords : steam turbine * thermodynamic properties * condensation Subject RIV: BJ - Thermodynamics

  18. Thermodynamic properties of minerals: Macroscopic and microscopic approaches

    International Nuclear Information System (INIS)

    Thermodynamic modeling of experimental or natural-phase equilibria has become an integral part of petrology. In this respect, the isobaric heat capacity (Cp) has manifold importance. First, Cp 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

  19. Thermodynamic property of gases in the sonoluminescing bubble

    Institute of Scientific and Technical Information of China (English)

    AN Yu; LI Guiqin; ZHOU Tieying

    2001-01-01

    With the theory of statistical physics dealing with chemical reaction (the law of mass action), the different thermodynamic property of noble gases (mono-atomic gases) in a small bubble and diatomic gases in a small bubble semi-quantitatively are analyzed. As bubbles of the mono-atomic and the diatomic gases are compressed, shock waves are produced in both bubbles. Though shock wave leads to sharp increase of pressure and temperature of gases in the bubble, diatomic gas will excitated vibrations and dissociate themselves to mono-atomic gas,these processes will consume many accumulated heat energy and block the further increase of the temperature. Therefore, compare with the mono-atomic gases in the bubble, there will be no enough charged particles ionized to flash for diatomic gases in the bubble, this may be the reason why a bubble of diatomic gases has no single bubble sonoluminescence while a bubble of noble gases has.

  20. A note on electrical and thermodynamic properties of Isolated Horizon

    CERN Document Server

    Chen, Gerui; Gao, Sijie

    2014-01-01

    The electrical laws and Carnot cycle of Isolated Horizon (IH) are investigated in this paper. We establish the Ohm's law and Joule's law of an Isolated Horizon, and find that the conceptual picture of black holes (Membrane Paradigm) can also apply to this kind of quasi-local black holes. We also investigate the geometrical properties near a non-rotating IH, and find that under the first-order approximation of r, there exist a Killing vector and a Hamiltonian conjugate to it, so this vector is a physical observer. We calculate the energy as measured at infinity of a particle at rest outside a non-rotating IH, and use this result to construct a reversible Carnot cycle with the Isolated Horizon as a cold reservoir, which confirms the thermodynamic nature of Isolated Horizon.

  1. Thermodynamic and kinetic properties of some diatomic gases

    Science.gov (United States)

    Holbrook, Robert Thomas, III

    1997-11-01

    In this work, the thermodynamic and kinetic properties of some diatomic gases are calculated and analyzed. In chapter 1, the partition functions of the species composing a dissociating and ionizing iodine vapor, specifically those for homonuclear diatomic 127I127I molecules, 127I atoms, 127I+ ions, and free electrons, are calculated. These partition functions are subsequently used in statistical mass action equations to determine the local thermal equilibrium dissociation degree a and the ionization degree φ of the iodine vapor over the temperature range 700 DyF, HoF, and TmF. Such systems are composed of seven different species: LnF and F2 molecules (Ln≡Dy, Ho, and Tm), LnF+ molecular ions, Ln and F atoms, LnF+ atomic ions, and free electrons. Once again, the partition functions are calculated for the various species and used in statistical expressions to determine the local thermal equilibrium compositions and thermodynamic properties of the LnF-based gas mixtures for the temperature range 3000 <= T/ /le 9000 K and initial molecular number densities 1014, 1016, and 1018 cm-3. Finally, in chapter 3, the Monte Carlo trajectory method is used to study the probabilities P(Vr, b, v1, J1, v2, J2) for dissociation via collisions between two ground electronic state X1Σ(0g+) I2 molecules. The two molecules interact with an impact parameter b and a relative speed Vr. The incident molecule is in the vibrational-rotational state specified by the vibrational quantum number v1 and the rotational quantum number J1 while the target molecule is in the state specified by the quantum numbers v2 and J2.

  2. Thermodynamic Properties of Liquids from Speed of Sound Measurements

    Directory of Open Access Journals (Sweden)

    Muhamed Bijedic

    2012-05-01

    Full Text Available A strategy for deriving thermodynamic properties of liquids (r, cp, cv from speed of sound is presented. It is based on numerical integration of differential equations connecting speed of sound with other thermodynamic properties. Two different procedures are recommended: One for liquids with lower and moderate critical pressures (LMCP, and another for liquids with higher critical pressures (HCP. The set of differential equations is solved as the initial value problem in both cases. However, for LMCP liquids initial conditions (several accurate values of r and cp are specified along isobar near the critical pressure, and for HCP liquids along the liquid-vapor saturation curve. The procedures are tested on ethane, carbon dioxide, and water.

  3. Modelling of phase diagrams and thermodynamic properties using Calphad method – Development of thermodynamic databases

    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

  4. 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.

  5. ms2: A molecular simulation tool for thermodynamic properties

    Science.gov (United States)

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

    2011-11-01

    This work presents the molecular simulation program ms2 that is designed for the calculation of thermodynamic properties of bulk fluids in equilibrium consisting of small electro-neutral molecules. ms2 features the two main molecular simulation techniques, molecular dynamics (MD) and Monte-Carlo. It supports the calculation of vapor-liquid equilibria of pure fluids and multi-component mixtures described by rigid molecular models on the basis of the grand equilibrium method. Furthermore, it is capable of sampling various classical ensembles and yields numerous thermodynamic properties. To evaluate the chemical potential, Widom's test molecule method and gradual insertion are implemented. Transport properties are determined by equilibrium MD simulations following the Green-Kubo formalism. ms2 is designed to meet the requirements of academia and industry, particularly achieving short response times and straightforward handling. It is written in Fortran90 and optimized for a fast execution on a broad range of computer architectures, spanning from single processor PCs over PC-clusters and vector computers to high-end parallel machines. The standard Message Passing Interface (MPI) is used for parallelization and ms2 is therefore easily portable to different computing platforms. Feature tools facilitate the interaction with the code and the interpretation of input and output files. The accuracy and reliability of ms2 has been shown for a large variety of fluids in preceding work. Program summaryProgram title:ms2 Catalogue identifier: AEJF_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEJF_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Special Licence supplied by the authors No. of lines in distributed program, including test data, etc.: 82 794 No. of bytes in distributed program, including test data, etc.: 793 705 Distribution format: tar.gz Programming language: Fortran90 Computer: The

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

    Directory of Open Access Journals (Sweden)

    T. Urbic

    2013-01-01

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

  7. Structure, thermodynamics, and dynamical properties of supercooled liquids

    International Nuclear Information System (INIS)

    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

  8. 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.

  9. Thermodynamic properties of three component solutions aviation kerosene-oil-H-hexane depending on temperature

    International Nuclear Information System (INIS)

    The results of experimental-theoretical studies of thermodynamic properties of three component solutions aviation kerosene-oil-H-hexane depending on temperature at atmospheric pressure are given. On the basis of law of corresponding states the empirical equation is obtained. By using the empirical equation the thermodynamic properties of studied solutions could be defined.

  10. Interphase thermodynamic bond in heterogeneous alloys: effects on alloy properties

    International Nuclear Information System (INIS)

    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

  11. THEWASP library. Thermodynamic water and steam properties library in GPU

    International Nuclear Information System (INIS)

    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)

  12. Thermodynamic properties and mixing thermodynamic parameters of two-phase metallic melts

    Institute of Scientific and Technical Information of China (English)

    Jian Zhang

    2005-01-01

    Based on the calculating model of metallic melts involving eutectic, the calculating equations of mixing thermodynamic parameters for two phase metallic melts have been formulated in the light of those equations of homogeneous solutions. Irrespective as to whether the activity deviation relative to Raoultian behavior is positive or negative, or the deviation is symmetrical or unsymmetrical, the evaluated results not only agree well with experimental values, but also strictly obey the mass action law. This testifies that these equations can authentically reflect the structural reality and mixing thermodynamic characteristics of two-phase metallic melts. The calculating equations of mixing thermodynamic parameters for the model of two phase metallic melts offer two practical criteria (activity and mixing thermodynamic parameters) and one theoretical criterion (the mass action law).

  13. Thermodynamic Properties and Mixing Thermodynamic Parameter of Binary Metallic Melt Involving Compound Formation

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jian

    2005-01-01

    Based on the coexistence theory of metallic melts involving compound formation,the theoretical cal culation equations of mixing thermodynamic parameters are established by giving up some empirical parameters in the associated solution model.For Fe-Al,Mn-Al and Ni-Al,the calculated results agree well with the experimental values,testifying that these equations can exactly embody mixing thermodynamic characteristics of these melts.

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

    Science.gov (United States)

    Singh, Gurpreet; Sharma, Rohit; Singh, Kuldip

    2015-09-01

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

  15. Measurement and correlation of physical properties of aqueous solutions of tetrabutylammonium hydroxide, piperazine and their aqueous blends

    Institute of Scientific and Technical Information of China (English)

    Rizwan Safdar; Abdul Aziz Omar; Lukman B Ismail; Arhama Bari; Bhajan Lal

    2015-01-01

    The density, viscosity and refractive index of aqueous solutions of tetrabutylammonium hydroxide (TBAOH), pi-perazine (PZ) and their aqueous blends are determined at several temperatures (303.15 to 333.15 K). All these measured physicochemical properties decreases with an increase in temperature. The density data is used to cal-culate the coefficient of thermal expansion and excess molar volume of al aqueous binary and ternary solutions. The coefficient of thermal expansion increases with increase in temperatures and concentrations. The negativity of excess molar volume for al the aqueous solution decreased with increase in temperature. Each physical prop-erty is correlated with temperature by least square method and the corresponding coefficients for each property are presented. The prediction values from correlations for the physical properties are in good agreement with the experimental values.

  16. Hydrogrossular (Katoite): Vibrational, Crystal-Chemical and Thermodynamic Properties

    Science.gov (United States)

    Dachs, E.; Geiger, C. A.

    2011-12-01

    There is great current interest in understanding interactions between H2O and its components and various Earth materials. Here, questions such as the bulk water content of the mantle, and what phases can incorporate OH- and in what concentrations come immediately to mind. In this regard, the hydrogarnet substitution (i.e., O4H4↔SiO4) has received special attention, because it is a verified mechanism for allowing the incorporation of OH- in garnet and possibly in other silicates as well. At relatively low temperatures there is complete solid solution between Ca3Al2Si3O12 and Ca3Al2O12H12. The latter, pure OH-containing end-member is termed katoite/hydrogrossular. Its crystal structure has been investigated by various workers using X-ray and neutron diffraction, including at high pressures. Little is known about its vibrational properties and its thermodynamic behavior is not fully understood. Thus, we studied the low temperature IR spectra and measured the heat capacity of katoite in order to investigate its vibrational, crystal-chemical and thermophysical properties. Katoite was synthesized hydrothermally in Au capsules at 250 °C and 3 kb water pressure. X-ray powder measurements show that about 98-99% katoite was obtained. Powder IR spectra were recorded between 298 K and 10 K. The spectra are considerably different in the high wavenumber region, where O-H stretching modes occur. At room temperature the IR-active O-H band located around 3662 cm-1 is broad and it narrows and shifts to higher wavenumbers and also develops structure below about 80 K. Concomitantly, additional weak intensity O-H bands located around 3600 cm-1 begin to appear and they become sharper and increase in intensity with further decreases in temperature. The spectra indicate that the vibrational behavior of individual OH groups and their collective interactions measurably affect the lattice dynamic (i.e. thermodynamic) behavior. The low temperature heat capacity behavior was investigated

  17. Critical, statistical, and thermodynamical properties of lattice models

    International Nuclear Information System (INIS)

    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.

  18. 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.)

  19. 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.

  20. Thermodynamic Properties of Non-Oxide Composite Refractories

    Institute of Scientific and Technical Information of China (English)

    HONG Yanruo; WU Hongpeng; SUN Jialin

    2005-01-01

    For initiative application of non-oxides in refractories, it is essential to study thermodynamic properties of non-oxides. The stability and stable order of non-oxides under oxidized atmosphere are analyzed firstly and then a new process, "converse reaction sintering", is proposed. The results of study on oxidation mechanism of silicon and aluminum nitrides indicate that the gaseous suboxides can be produced observably when the oxygen partial pressure is lower than "conversion oxygen partial pressure". The suboxides can be deposited near the surface of composite to become a compact layer. This causes the material possessing a performance of "self-impedient oxidation". Metal Si and Al are the better additives for increasing the density and width of compact layer and increasing the ability of anti-oxidation and anti-corrosion. The study on Si3N4-Al2O3, Si3N4-MgO, Si3N4-SiC systems is also enumerated as examples in the paper. The experimental results show that the converse reaction sintering is able to make high performance composites and metal Si and Al not only can promote the sintering but also increase the density and width of compact layer.

  1. Kinetic, isotherm and thermodynamic studies of amaranth dye biosorption from aqueous solution onto water hyacinth leaves.

    Science.gov (United States)

    Guerrero-Coronilla, Imelda; Morales-Barrera, Liliana; Cristiani-Urbina, Eliseo

    2015-04-01

    The present study explored the kinetics, equilibrium and thermodynamics of amaranth (acid red 27) anionic dye (AD) biosorption to water hyacinth leaves (LEC). The effect of LEC particle size, contact time, solution pH, initial AD concentration and temperature on AD biosorption was studied in batch experiments. AD biosorption increased with rising contact time and initial AD concentration, and with decreasing LEC particle size and solution pH. Pseudo-second-order chemical reaction kinetics provided the best correlation for the experimental data. Isotherm studies showed that the biosorption of AD onto LEC closely follows the Langmuir isotherm, with a maximum biosorption capacity of about 70 mg g(-1). The thermodynamic parameters confirm that AD biosorption by LEC is non-spontaneous and endothermic in nature. Results indicate that LEC is a strong biosorbent capable of effective detoxification of AD-laden wastewaters. PMID:25617874

  2. The thermodynamic characteristics of ion resolvation in aqueous solutions of dimethylformamide and dimethylsulfoxide

    International Nuclear Information System (INIS)

    Data on thermodynamic characteristics of chlorine, bromine and iodine ion resolution in mixtures of water with dimethylformamide and dimethylsulfoxide are provided and analyzed. The values presented were calculated on the basis of the volt potential differences method. It is shown the actual thermodynamic characteristics of anion transfer have positive values in contrast to cations having the opposite sign. It stems from changes in the structure of mixed solvent when passing from water to water-organic mixtures in the solution/gas phase interface. Analysis of chemical Gibbs' energies of resolvation of the ions studied suggests that anions, which can form hydrogen bonds with proton-donor solvents, are hardly solved in aprotic solutions

  3. Hanford River Protection Project Enhanced Mission Planning Through Innovative Tools: Lifecycle Cost Modeling And Aqueous Thermodynamic Modeling - 12134

    International Nuclear Information System (INIS)

    Two notable modeling efforts within the Hanford Tank Waste Operations Simulator (HTWOS) are currently underway to (1) increase the robustness of the underlying chemistry approximations through the development and implementation of an aqueous thermodynamic model, and (2) add enhanced planning capabilities to the HTWOS model through development and incorporation of the lifecycle cost model (LCM). Since even seemingly small changes in apparent waste composition or treatment parameters can result in large changes in quantities of high-level waste (HLW) and low-activity waste (LAW) glass, mission duration or lifecycle cost, a solubility model that more accurately depicts the phases and concentrations of constituents in tank waste is required. The LCM enables evaluation of the interactions of proposed changes on lifecycle mission costs, which is critical for decision makers.

  4. HANFORD RIVER PROTECTION PROJECT ENHANCED MISSION PLANNING THROUGH INNOVATIVE TOOLS LIFECYCLE COST MODELING AND AQUEOUS THERMODYNAMIC MODELING - 12134

    Energy Technology Data Exchange (ETDEWEB)

    PIERSON KL; MEINERT FL

    2012-01-26

    Two notable modeling efforts within the Hanford Tank Waste Operations Simulator (HTWOS) are currently underway to (1) increase the robustness of the underlying chemistry approximations through the development and implementation of an aqueous thermodynamic model, and (2) add enhanced planning capabilities to the HTWOS model through development and incorporation of the lifecycle cost model (LCM). Since even seemingly small changes in apparent waste composition or treatment parameters can result in large changes in quantities of high-level waste (HLW) and low-activity waste (LAW) glass, mission duration or lifecycle cost, a solubility model that more accurately depicts the phases and concentrations of constituents in tank waste is required. The LCM enables evaluation of the interactions of proposed changes on lifecycle mission costs, which is critical for decision makers.

  5. Utilization of chitosan-clinoptilolite composite for the removal of radiocobalt from aqueous solution. Kinetics and thermodynamics

    International Nuclear Information System (INIS)

    Chitosan-clinoptilolite composite was prepared and tested for removing radiocobalt from aqueous solution. The composite was characterized with Fourier transform infrared spectroscopy, X-ray diffraction analysis and scanning electron microscopy coupled with energy dispersive X-ray analysis. The sorption of Co(II) on chitosan-clinoptilolite composite was pH-dependent and ionic strength-independent. The kinetic sorption was fitted well by a pseudo-second-order rate equation. The thermodynamic parameters (ΔH0, ΔS0, ΔG0) revealed that the sorption of Co(II) on chitosan-clinoptilolite composite was spontaneous and endothermic. The study showed that chitosan-clinoptilolite composite had excellent potential for the treatment of wastewater containing radiocobalt. (author)

  6. Rheological properties of aqueous solutions of biopolymeric hyaluronan

    Science.gov (United States)

    Szwajczak, Elzbieta

    2004-09-01

    Aqueous solutions of hyaluronic acid (hyaluronan, HA) were studied. The HA compound is a natural polysaccharide, bipolymer. It plays an important role in numerous biological processes as a component of the extracellular matrix, connective tissues and, especially, human and animal synovial joints. Natural and artificial solutions of the HA have demonstrated the viscoelastic nature. These properties are shown to be related to the microstructure parameters (bulk concentration, molecular weight) and external parameters (temperature, stress, shear rate). We emphasize the role of the flow properties of polymeric systems. It is found a liquid crystalline "order" can be "induced" during the material flow. The dynamic properties, such as the elastic shear modulus and viscous shear modulus, are given. These results are discussed in relation to the postulated function of hyaluronic acid in synovial joint and with respect to possibilities o their application in medicine and pharmacology.

  7. Practical thermodynamic quantities for aqueous vanadium- and iron-based flow batteries

    Science.gov (United States)

    Hudak, Nicholas S.

    2014-12-01

    A simple method for experimentally determining thermodynamic quantities for flow battery cell reactions is presented. Equilibrium cell potentials, temperature derivatives of cell potential (dE/dT), Gibbs free energies, and entropies are reported here for all-vanadium, iron-vanadium, and iron-chromium flow cells with state-of-the-art solution compositions. Proof is given that formal potentials and formal temperature coefficients can be used with modified forms of the Nernst Equation to quantify the thermodynamics of flow cell reactions as a function of state-of-charge. Such empirical quantities can be used in thermo-electrochemical models of flow batteries at the cell or system level. In most cases, the thermodynamic quantities measured here are significantly different from standard values reported and used previously in the literature. The data reported here are also useful in the selection of operating temperatures for flow battery systems. Because higher temperatures correspond to lower equilibrium cell potentials for the battery chemistries studied here, it can be beneficial to charge a cell at higher temperature and discharge at lower temperature. Proof-of-concept of improved voltage efficiency with the use of such non-isothermal cycling is given for the all-vanadium redox flow battery, and the effect is shown to be more pronounced at lower current densities.

  8. Thermodynamic properties and phase equilibria of selected Heusler compounds

    Science.gov (United States)

    Yin, Ming

    Heusler compounds are ternary intermetallics with many promising properties such as spin polarization and magnetic shape memory effect. A better understanding of their thermodynamic properties facilitates future design and development. Therefore, standard enthalpies of formation and heat capacities from room temperature to 1500 K of selected Heusler compounds X2YZ (X = Co, Fe, Ni, Pd, Rh, Ru; Y = Co, Cu, Fe, Hf, Mn, Ni, Ti, V, Zr; Z = Al, Ga, In, Si, Ge, Sn) and half-Heusler compounds XYSn (X = Au, Co, Fe, Ir, Ni, Pd, Pt, Rh; Y = Hf, Mn, Ti, Zr) were measured using high temperature direct reaction calorimetry. The measured standard enthalpies of formation were compared with those predicted from ab initio calculations and the extended semi-empirical Miedema's model. Trends in standard enthalpy of formation with respect to the periodic classification of elements were discussed. The effect of a fourth element (Co, Cu, Fe, Pd; Ti, V; Al, Ga, In, Si, Ge) on the standard enthalpy of formation of Ni2MnSn was also investigated. Lattice parameters of the compounds with an L21 structure were determined using X-ray powder diffraction analysis. Differential scanning calorimetry was used to determine melting points and phase transformation temperatures. Phase relationships were investigated using scanning electron microscopy with an energy dispersive spectrometer. The isothermal section of the Fe-Sn-Ti ternary system at 873 K was established using equilibrated alloys. Three ternary compounds including the Heusler compound Fe2SnTi were observed. A new ternary compound Fe5Sn9Ti 6 was reported and the crystal structure of FeSnTi2 was determined for the first time.

  9. Rheological properties of ceramic nanopowders in aqueous and nonaqueous suspensions

    International Nuclear Information System (INIS)

    The potential for ceramic nanocomposites to offer significantly enhanced mechanical properties is generally known since the first work of Niihara published in 1991. However achieving these properties needs carefully done colloidal processing, because ceramic nanopowders are naturally prone to agglomeration. The work presented here is concerned with the processing of zirconia/alumina nanocomposites via aqueous and alumina silicon carbide nanocomposites via nonaqueous colloidal route. The effect of pH of aqueous alumina and zirconia suspensions on properties of suspension and centrifuged green bodies was studied. A correlation between surface electric charge of grains (zeta potential)and agglomerate size, viscosity of suspension and porosity of green compacts was found. In the case of nonaqueous route alumina and silicon carbide suspensions in iso-propanol were investigated. Electrostatic surface charge of grains was changed by addition of chloroacetic acid and determined indirectly by the mass of powder deposited on electrode during electrophoresis. Different behaviour of SiC nanopowder than of alumina was observed and mechanism of charge creation is proposed on the base of DLVO theory. The effect of grain charge on preventing agglomeration on the silicon carbide powder is presented on micrographs of sintered nanocomposites. (author)

  10. RHEOLOGICAL PROPERTIES OF WHEAT GLIADINS IN AQUEOUS PROPANOL

    Institute of Scientific and Technical Information of China (English)

    Shao-min Sun; Yi-hu Song; Qiang Zheng

    2013-01-01

    Rheological properties of wheat gliadins in 50% (V/V) aqueous propanol were carried out as a function of gliadin concentration c and temperature.The solutions at 20 g L-1 to 200 g L-1 behave as Newtonian fluids with an flow activation energy of 23.5-27.3 kJ mol-1.Intrinsic viscosity [η] and Huggins constant kn are determined according to Huggins plot at c ≤120 gL-1.The results reveal that gliadins are not spherical shaped and the molecular size tends to increase with temperature due to improved solvation.

  11. An Electrochemical Investigation of the Redox Properties of Murexide in Aqueous and Non-Aqueous Media

    Directory of Open Access Journals (Sweden)

    Hossnia S. Mohran

    2009-01-01

    Full Text Available Knowledge of solvent effects on the redox properties of Murexide (Mu is important for understanding its role as an electron acceptor in analytical and inorganic chemistry. In the present study, an investigation of the electrochemical behavior of the compound by both Cyclic Voltammetry (CV and Electrochemical Impedance Spectroscopy (EIS in both aqueous and non-aqueous solutions was undertaken. It is suggested that, the reaction mechanism proceeds according to an Erev CE-rev-route. This reaction mechanism is confirmed by the CV behavior for barbituric acid, which is essentially represent a main part of murexide, under the same conditions. In DMSO, the one-electron reduction potential peak of murexide was found to shift positively by 223 mV to the value of the corresponding wave obtained in DMF under the same conditions. The shift is most readily explained by the presence of murexide aggregates in DMF. The one-electron oxidation potential position is relatively unaffected by aggregation. The data has also revealed that murexide decomposes in the level of radical anion at the N = C bond into two approximately equal units. In aqueous sodium perchlorate (NaClO4 solutions, it is suggested that the decomposion of murexide is relatively slow, leading to nearly a reversible 1e-transfer process (E-mechanism. In both KNO3 and KCl solutions, the one-electron transfer step of murexide was found to be an adsorption wave. The Electrochemical Impedance (EIS response of murexide is either low-frequency Warburg impedance or a capacitive semicircle behavior at high frequencies, depending on the medium.

  12. Equilibrium, thermodynamic and kinetic studies on aluminum biosorption from aqueous solution by brown algae (Padina pavonica) biomass

    International Nuclear Information System (INIS)

    This paper presents the equilibrium, thermodynamic and kinetic studies on aluminum biosorption from aqueous solution by brown algae (Padina pavonica) biomass. Optimum biosorption conditions were determined as a function of pH, biomass dosage, contact time, and temperature. Langmuir, Freundlich and Dubinin-Radushkevich (D-R) models were applied to describe the biosorption isotherm of Al(III) by P. pavonica biomass. The biosorption capacity of P. pavonica biomass was found as 77.3 mg/g. The metal ions were desorbed from P. pavonica using 1 M HCl. The high stability of P. pavonica permitted a slight decrease about 20% in the recovery of Al(III) ions after 10 times of adsorption-elution process. The mean free energy value evaluated from the D-R model indicated that the biosorption of Al(III) onto P. pavonica biomass was taken place by chemical ion exchange. The calculated thermodynamic parameters, ΔGo, ΔHo and ΔSo showed that the biosorption of Al(III) onto P. pavonica biomass was feasible, spontaneous and endothermic under examined conditions. Experimental data was also tested in terms of biosorption kinetics using pseudo-first-order and pseudo-second-order kinetic models. The results showed that the biosorption processes of Al(III) onto P. pavonica biomass followed well pseudo-second-order kinetics.

  13. Experimental determination and thermodynamic modeling of phase equilibrium and protein partitioning in aqueous two-phase systems containing biodegradable salts

    International Nuclear Information System (INIS)

    Highlights: ► Binodal data of systems (water + polyethyleneglycol + sodium) succinate are reported. ► Pitzer model describes the phase equilibrium of systems formed by polyethyleneglycol and biodegradable salts satisfactorily. ► This simple thermodynamic framework was able to predict the partitioning behaviour of model proteins acceptably well. - Abstract: Phase diagrams of sustainable aqueous two-phase systems (ATPSs) formed by polyethyleneglycols (PEGs) of different average molar masses (4000, 6000, and 8000) and sodium succinate are reported in this work. Partition coefficients (Kps) of seven model proteins: bovine serum albumin, catalase, beta-lactoglobulin, alpha-amylase, lysozyme, pepsin, urease and trypsin were experimentally determined in these systems and in ATPSs formed by the former PEGs and other biodegradable sodium salts: citrate and tartrate. An extension of Pitzer model comprising long and short-range term contributions to the excess Gibbs free energy was used to describe the (liquid + liquid) equilibrium. Comparison between experimental and calculated tie line data showed mean deviations always lower than 3%, thus indicating a good correlation. The partition coefficients were modeled by using the same thermodynamic approach. Predicted and experimental partition coefficients correlated quite successfully. Mean deviations were found to be lower than the experimental uncertainty for most of the assayed proteins.

  14. Mineral solubilities in aqueous fluids at high pressures and temperatures: New thermodynamic model and implications for mass transfer in the Earth's crust and mantle

    Science.gov (United States)

    Dolejš, David; Manning, Craig E.

    2010-05-01

    Aqueous fluids are produced by metamorphic devolatilization and magmatic activity in a variety of settings including continental orogens, subduction zones with magmatic arcs as well as oceanic ridges and sea floor. They are responsible for mobility and transport of inorganic and organic solutes as manifested by alteration or veining, distinct element depletion-enrichment patterns or isotopic disturbances. The impact of many fluid-mediated processes is promoted by high time-integrated fluid fluxes, 101-106 m3 m-2, inferred for diffuse and focused fluid flow through lithosphere. Previous approaches to aqueous speciation have almost exclusively been based on the Helgeson-Kirkham-Flowers equation of state, which, however, suffers from inaccuracies in the vicinity of critical point of water and cannot be extrapolated to very high temperatures and pressures due to the lack of experimental data on dielectric constant of H2O. We propose a new thermodynamic model for dissolution of minerals in aqueous fluids at high temperatures and pressures, which is derived from individual energetic contributions to lattice breakdown, solute hydration and compression of the hydration shell. The thermodynamic properties depend on temperature and H2O density only and are calculated using three to five model parameters calibrated by experimental data. Our formulation of the density dependence has the advantage of behaving as a smooth function at the critical point of H2O, it closely corresponds to the generalized Krichevskii parameter, and it linearly correlates with the Born electrostatic energy. Solubilities of quartz, corundum, rutile, calcite, apatite, fluorite, and portlandite monotonously increase for a given phase by 4-5 orders of magnitude as temperature rises from 200 to 1100 oC along typical geotherms. At constant pressure, however, mineral solubilities initially increase with rising temperature, but subsequently drop. This effect results from a reversal in isobaric expansivity of

  15. Thermodynamic properties of 1-butyl-3-methylpyridinium tetrafluoroborate

    Energy Technology Data Exchange (ETDEWEB)

    Safarov, Javid, E-mail: javid.safarov@uni-rostock.de [Institute of Technical Thermodynamics, University of Rostock, Albert-Einstein-Str. 2, D-18059 Rostock (Germany); Department of Heat and Refrigeration Techniques, Azerbaijan Technical University, H. Javid Avn. 25, AZ1073 Baku (Azerbaijan); Kul, Ismail [Department of Chemistry, Department of Biochemistry, Widener University, One University Place, Chester, PA 19013 (United States); El-Awady, Waleed A. [Department of Heat and Refrigeration Techniques, Azerbaijan Technical University, H. Javid Avn. 25, AZ1073 Baku (Azerbaijan); Mechanical Power Engineering Department, Mansoura Univeristy, Mansoura (Egypt); Shahverdiyev, Astan [Department of Heat and Refrigeration Techniques, Azerbaijan Technical University, H. Javid Avn. 25, AZ1073 Baku (Azerbaijan); Hassel, Egon [Institute of Technical Thermodynamics, University of Rostock, Albert-Einstein-Str. 2, D-18059 Rostock (Germany)

    2011-09-15

    Highlights: > (p, {rho}, 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, {rho}, T) data of 1-butyl-3-methylpyridinium tetrafluoroborate [C4mpyr][BF{sub 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 {Delta}{rho}/{rho} = {+-}(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, {rho}, T) data of [C4mpyr][BF{sub 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.

  16. Thermodynamic properties of 1-butyl-3-methylpyridinium tetrafluoroborate

    International Nuclear Information System (INIS)

    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][BF4] 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][BF4] 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.

  17. Thermodynamic and kinetic studies of biosorption of iron and manganese from aqueous medium using rice husk ash

    Science.gov (United States)

    Adekola, F. A.; Hodonou, D. S. S.; Adegoke, H. I.

    2014-11-01

    The adsorption behavior of rice husk ash with respect to manganese and iron has been studied by batch methods to consider its application for water and waste water treatment. The optimum conditions of adsorption were determined by investigating the effect of initial metal ion concentration, contact time, adsorbent dose, pH value of aqueous solution and temperature. Adsorption equilibrium time was observed at 120 min. The adsorption efficiencies were found to be pH dependent. The equilibrium adsorption experimental data were found to fit the Langmuir, Freundlich and Temkin isotherms for iron, but fitted only Langmuir isotherm for manganese. The pseudo-second order kinetic model was found to describe the manganese and iron kinetics more effectively. The thermodynamic experiment revealed that the adsorption processes involving both metals were exothermic. The adsorbent was finally applied to typical raw water with initial manganese and iron concentrations of 3.38 mg/l for Fe and 6.28 mg/l, respectively, and the removal efficiency was 100 % for Mn and 70 % for Fe. The metal ions were desorbed from the adsorbent using 0.01 M HCl, it was found to quantitatively remove 67 and 86 % of Mn and Fe, respectively, within 2 h. The results revealed that manganese and iron are considerably adsorbed on the adsorbent and could be an economic method for the removal of these metals from aqueous solutions.

  18. 1H NMR structural and thermodynamical analysis of the hetero-association of daunomycin and novatrone in aqueous solution

    Science.gov (United States)

    Veselkov, A. N.; Evstigneev, M. P.; Rozvadovskaya, A. O.; Hernandez Santiago, A.; Zubchenok, O. V.; Djimant, L. N.; Davies, D. B.

    2004-09-01

    The complexation of antitumour antibiotics novatrone (NOV) and daunomycin (DAU) in aqueous solution has been studied by one- and two-dimensional 1H-NMR spectroscopy (500 MHz) in order to elucidate the probable molecular mechanism of the action of aromatic antitumour drugs in combination chemotherapy. The equilibrium reaction constants, thermodynamical parameters (Δ H, Δ S) of hetero-association of NOV with DAU and the limiting values of proton chemical shifts of the molecules in the hetero-complexes have been determined from the experimental concentration and temperature dependences of proton chemical shifts of the aromatic molecules. The most favourable structure of the 1:1 NOV-DAU hetero-association complex has been determined using both the molecular mechanics methods (X-PLOR software) and the limiting values of proton chemical shifts of the molecules. The obtained results have shown that intermolecular complexes between NOV and DAU molecules are mainly stabilized by stacking interactions of the aromatic chromophores. It is likely that there is an additional stabilization of the NOV-DAU hetero-complexes by intermolecular hydrogen bonds. It is concluded that aromatic molecules of antibiotics may form energetically stable hetero-association complexes in aqueous solution and hence effect their medical-biological (and probably toxic) activity.

  19. Thermodynamic and kinetic study of the intrinsic adsorption capacity of graphene oxide for malachite green removal from aqueous solution

    Directory of Open Access Journals (Sweden)

    Prawit Nuengmatcha

    2014-12-01

    Full Text Available Graphene oxide (GO was produced from bare graphite (BGP material and was used as anintrinsic adsorbent for the removal of malachite green (MG from aqueous solution. In an optimization study, the effects of the initial concentration of MG, solution pH, adsorbent dosage, contact time and ionic strength were investigated in detail. The water-soluble dye was analyzed at a maximum wavelength of 618 nm. The optimum conditions for MG removal from aqueous solution included a 300 mg/L initial concentration with 0.02 mg adsorbent at pH 5.1, and complete adsorption equilibrium was reached within 40 min. The maximum adsorption capacity of GO for MG was 384.62 mg/g, dramatically higher (over 10 times than that of BGP (28.73 mg/g.The adsorption process followed pseudo-second-order kinetics. Thermodynamic data demonstrated that dye adsorption onto the GO surface was mainly an exothermic spontaneous reaction. The remarkably different adsorption isotherms for GO and BGP fit well with the Langmuir and Freundlich models, respectively. It is therefore evident that the prepared GO can be used as a highly effective adsorbent for this toxic dye.

  20. Equilibrium, kinetic and thermodynamic studies for sorption of Ni (II from aqueous solution using formaldehyde treated waste tea leaves

    Directory of Open Access Journals (Sweden)

    Jasmin Shah

    2015-05-01

    Full Text Available The sorption characteristic of Ni (II from aqueous solution using formaldehyde treated waste tea leaves as a low cost sorbent has been studied. The effect of pH, contact time, sorbent dose, initial metal ion concentration and temperature were investigated in batch experiments. The equilibrium data were fitted into four most common isotherm models; Freundlich, Langmuir, Tempkin and Dubinin–Radushkevich (D–R. The Langmuir model described the sorption isotherm best with maximum monolayer sorption capacity of 120.50 mg g−1. Four kinetic models, pseudo-first-order, pseudo-second-order, intraparticle diffusion and Elovich were employed to explain the sorption mechanism. The kinetics of sorption data showed that the pseudo-second-order model is the best with correlation coefficient of 0.9946. The spontaneous and exothermic nature of the sorption process was revealed from thermodynamic investigations. The effect of some common alkali and alkaline earth metal ions were also studied which showed that the presence of these ions have no effect on the sorption of Ni (II. The results showed that waste tea leaves have the potential to be used as a low cost sorbent for the removal of Ni (II from aqueous solutions.

  1. ADSORPTION OF Pb2+ IONS FROM AQUEOUS SOLUTIONS ONTO BAEL TREE LEAF POWDER: ISOTHERMS, KINETICS AND THERMODYNAMICS STUDY

    Directory of Open Access Journals (Sweden)

    P. SENTHIL KUMAR

    2009-12-01

    Full Text Available In this study, bael tree (BT leaf powder was used as an adsorbent for removal of Pb2+ ions from aqueous solutions through batch equilibrium technique. The influence of pH, equilibrium time, temperature, adsorbent dosage and initial concentration of metal ions on adsorbed amount of metals ions were investigated. Studies showed that the pH of aqueous solutions affected Pb2+ ions removal as a result of removal efficiency increased with increasing solution pH. The experimental isotherm data were analyzed using the Langmuir, Freundlich, Temkin and Dubinin-Radushkevich equations. The monolayer adsorption capacity is 4.065 mg/g with the correlation coefficient of 0.993. The experiments showed that highest removal rate was 84.93% at solution pH 5, contact time 60 min and initial concentration of 50 mg/L. Thermodynamic parameters such as Gibbs free energy, enthalpy, and entropy have also been evaluated and it has been found that the sorption process was feasible, spontaneous and exothermic in nature. Three simplified kinetic models including a pseudo-first-order equation, pseudo-second-order equation and intraparticle diffusion equation were selected to follow the adsorption process. Kinetic parameters, rate constants, equilibrium sorption capacities and related correlation coefficients, for each kinetic model were calculated and discussed. It was shown that the adsorption of Pb2+ ions could be described by the pseudo-second order equation, suggesting that the adsorption process is presumable a chemisorption.

  2. A CALPHAD study on the thermodynamic stability of calcium-, zinc-, and yttrium-doped magnesium in aqueous environments

    International Nuclear Information System (INIS)

    Highlights: ► Execution of CALPHAD thermodynamic study and hydrolysis reactions of Mg-alloys. ► CALPHAD and ab-initio studies demonstrate very similar results in pure water. ► Alloying of Mg with Ca and Y promote hydrolysis, while Zn resists the hydrolysis. ► Mg-(Ca, Y, Zn) alloys yield similar stability effects in water and in bio-solution. ► Kinetic aspects are vital for aqueous stability studies of biodegradable Mg-alloys. - Abstract: Magnesium has attracted the attention of the biomaterials community as a potential biodegradable metallic candidate for use in stents and orthopedic applications. Alloying of Mg with metals such as Ca, Y and Zn, etc., to form alloy precursors is important to optimize its corrosion rate in electrolytic and aqueous environments to understand the alloy response in body fluid environments. In the current study, the chemical reactions of Mg–Me alloys (Me = Ca, Y, and Zn) with pure water have been investigated using the CALPHAD technique. A qualitative agreement between CALPHAD and first-principles results has been obtained. The CALPHAD method has also been employed to study the reactions of Mg alloys in the human blood fluid environment. The effects of alloying elements and compositions on the reaction enthalpies, reaction products, amount of gas release and gas compositions as well as the pH of the fluids have been systematically discussed and reported.

  3. Computer codes used in the calculation of high-temperature thermodynamic properties of sodium

    International Nuclear Information System (INIS)

    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

  4. Biosorption of Copper (II) from Aqueous Solution by Saccharomyces cerevisiae : Kinetics and Thermodynamics

    OpenAIRE

    BALBASI, Muzaffer; Tosun, Ayse; AKCELIK, Oznur; Ergun, Mubeccel

    2012-01-01

    Biosorption equilibrium, kinetics, and thermodynamics of Cu ions onto S. cerevisiae  were studied in a batch system with respect to temperature and initial ion concentration. Biosorption efficiency  increased up to Cu ion initial concentration of 75 mg/L, and then decreased with the increasing metal ion concentration. Equilibrium uptake value changed from 9.8 mg/g at 20º C to 14.5 mg/g at 50º C. Langmuir isotherm model was found to be in good correlation with data.. Biosor...

  5. Electronic and thermodynamic properties of transition metal elements and compounds

    International Nuclear Information System (INIS)

    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 VC1-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

  6. Biosorption of Cr(VI) from AqueousSolution Using New Adsorbent: Equilibrium and Thermodynamic Study

    OpenAIRE

    Zainal, Israa G.

    2010-01-01

    Biosorption is one such emerging technology which utilized naturally occurring waste materials to sequester heavy metals from polluted water. In the present study cinnamon was utilized for Cr(VI) removal from aqueous solutions.It was found that a time of two hours was sufficient for sorption to attain equilibrium. The optimum pH was 2 for Cr(VI) removal. Temprature has little influence on the biosorption process. The Cr(VI) removal decreased with increase in temperature. The biosorption data ...

  7. Kinetics and Thermodynamics of Oil Extraction from Sun ower Seeds in the Presence of Aqueous Acidic

    OpenAIRE

    TOPALLAR, Hüseyin

    2000-01-01

    Oil extraction was performed in aqueous HCl, H2SO4 and H3PO4 solutions with n-hexane (C6H14) at 30, 40, 50 and 60 oC using 10 gr of sunflower seeds over 1 h with 10-min. sampling intervals. The optimum acid concentration was wt. 10% for each acid, and the highest oil yield was obtained in the extraction procedure with n-hexane containing H2SO4. The extraction process was observed with regard to the percent oil yield versus time, and the reaction order was found to be first-order kinetics by t...

  8. Statistical Thermodynamic Model for Surface Tension of Aqueous Organic Acids with Consideration of Partial Dissociation.

    Science.gov (United States)

    Boyer, Hallie C; Dutcher, Cari S

    2016-06-30

    With statistical mechanics, an isotherm-based surface tension model for single solute aqueous solutions was derived previously (Wexler et al. J. Phys. Chem. Lett. 2013) for the entire concentration range, from infinite dilution to pure liquid solute, as a function of solute activity. In recent work (Boyer et al. J. Phys. Chem. Lett. 2015), empirical model parameters were reduced through physicochemical interpretations of both electrolyte and organic solutes, enabling surface tension predictions for systems where there is little or no data. The prior binary model is extended in the current work for the first time to treat multicomponent systems to predict surface tensions of partially dissociating organic acids (acetic, butyric, citric, formic, glutaric, maleic, malic, malonic, oxalic, propionic, and succinic acids). These organic acids are especially applicable to the study of atmospheric aqueous aerosols, due to their abundance in the atmosphere. In the model developed here, surface tension depends explicitly on activities of both the neutral organic and deprotonated components of the acid. The relative concentrations of the nondissociated and dissociated mole fractions are found using known dissociation constants. Model parameters strongly depend on molecular size, number of functional groups, O:C ratio, and number of carbons. For all organic acids in this study, fully predictive modeling of surface tensions is demonstrated. PMID:27219322

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2002-07-18

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

  11. Biosorption of nickel(II) from aqueous solution by brown algae: Equilibrium, dynamic and thermodynamic studies

    International Nuclear Information System (INIS)

    The biosorption characteristics of nickel(II) ions using the brown algae (Cystoseria indica, Nizmuddinia zanardini, Sargassum glaucescens and Padina australis) were investigated. Experimental parameters affecting the biosorption process such as pH level, contact time, initial metal concentration and temperature were studied. The equilibrium data fitted very well to the Langmuir adsorption model in the concentration range of nickel(II) ions and at all the temperatures studied. Evaluation of the experimental data in terms of biosorption dynamics showed that the biosorption of nickel(II) onto algal biomass followed the pseudo-second-order dynamics well. The calculated thermodynamic parameters (ΔGo, ΔHo and ΔSo) showed that the biosorption of nickel(II) ions were feasible, spontaneous and endothermic at the temperature ranges of 293-313 K.

  12. Thermodynamics of the interaction between hydroxypropyl-α-cyclodextrin and alkanols in aqueous solutions

    International Nuclear Information System (INIS)

    The interactions of hydroxypropyl-α-cyclodextrin (HP-α-CD) with 1-alkanols and with some α,ω-alkanediols have been studied by calorimetric titration at 298.15 K. This technique enables the determination of the enthalpy and association constant for the complex formation, from which Gibbs energy and entropy can be derived. The results are compared to those reported for the complex formation between the native α-cyclodextrin (α-CD) and 1-alkanols or α,ω-alkanediols in the literature. Thermodynamic parameters corresponding to the transfer process of the alkanol from the native to the modified α-CD are also calculated. The results clearly show that the hydrophobic interactions are important in this process, but there are other effects like the size of the alkanol that are also of some importance

  13. Thermodynamics of the formation of copper(II) complexes with L-histidine in aqueous solution

    Science.gov (United States)

    Gorboletova, G. G.; Metlin, A. A.

    2015-02-01

    The heat effects from the reaction between L-histidine solutions and Cu(NO3)2 solutions at 298.15 K in the 0.2 to 1.0 (KNO3) range of ionic strength are measured by means of direct calorimetry. The experimental data is treated with allowance for the simultaneous proceeding of several processes. The heat effects of the formation of complexes Cu(His)+, Cu(His)2, CuHHis2+, CuH(His){2/+} and CuH2(His){2/2+} are calculated from calorimetric measurements. The standard enthalpies of formation for complexes of L-histidine with Cu2+ ions are obtained via extrapolation to zero ionic strength. The relationship between the thermodynamic characteristics of the formation of complexes of copper(II) with L-histidine and their structure is determined.

  14. Standard thermodynamic functions of Co2+ complexation with glycine and L-histidine in aqueous solution

    Science.gov (United States)

    Gorboletova, G. G.; Metlin, A. A.

    2016-02-01

    The enthalpies of the reactions between solutions of Co(NO3)2 and solutions of glycine (Gly) and L-histidine (His) are determined via direct calorimetry at different pH values and metal: ligand ratios using KNO3 as a background electrolyte ( T = 298.15 K, I = 0.2-1.0). The enthalpy changes upon the formation of cobalt glycinate complexes and Co2+ mixed-ligand complex, viz., glycine-L-histidine, were calculated. The standard thermodynamic parameters (Δr H°, Δr G°, Δr S°) of complexation are determined. The CoGlyHis complex is shown to be stable toward decomposition into homogeneous complexes.

  15. Thermodynamic properties of a rotating Bose–Einstein condensation in a 2D optical lattice

    International Nuclear Information System (INIS)

    In this paper, we consider the thermodynamic properties of a rotating Bose–Einstein condensation in a 2D optical lattice. A modified semiclassical approximation is suggested to calculate the condensate fraction, the transition temperature and the heat capacity. Our approach provides a consistent picture for the role of the optical potential and the rotation rate on the temperature dependence for the thermodynamic properties. The outcome results furnish useful qualitatively theoretical results for the future BEC experiments in such traps.

  16. Thermodynamic properties of a rotating Bose–Einstein condensation in a 2D optical lattice

    Energy Technology Data Exchange (ETDEWEB)

    El-Badry, Azza M., E-mail: elbadry.azza@yahoo.com [Department of Physics, Faculty of Science, El Minia University, El Minia (Egypt); Hassan, Ahmed S. [Department of Physics, Faculty of Science, El Minia University, El Minia (Egypt); Abdel-Gany, Hend A. [Department of Physics, Faculty of Science, Cairo University, Giza (Egypt)

    2014-07-01

    In this paper, we consider the thermodynamic properties of a rotating Bose–Einstein condensation in a 2D optical lattice. A modified semiclassical approximation is suggested to calculate the condensate fraction, the transition temperature and the heat capacity. Our approach provides a consistent picture for the role of the optical potential and the rotation rate on the temperature dependence for the thermodynamic properties. The outcome results furnish useful qualitatively theoretical results for the future BEC experiments in such traps.

  17. Pyrene-modified unlocked nucleic acids: synthesis, thermodynamic studies, and fluorescent properties

    DEFF Research Database (Denmark)

    Karlsen, Kasper K; Pasternak, Anna; Jensen, Troels B; Wengel, Jesper

    2012-01-01

    -UNA modifications were studied. It was found that incorporation of pyrene-UNA monomers increased duplex stability relative to UNA monomers, and thermodynamic studies revealed significant mismatch discriminative capabilities of the pyrene-UNA modified oligonucleotides. Furthermore, the steady-state fluorescence......Two pyrene-modified UNA monomers were synthesized and incorporated into 21-mer DNA oligonucleotides. Melting temperatures and thermodynamic properties of the modified duplexes were measured, and the fluorescence properties of single strands and duplexes containing one or more pyrene...

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

    OpenAIRE

    Santos, Andrés

    2013-01-01

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

  19. Thermodynamics of inclusion complexes of natural and modified cyclodextrins with acetylsalicylic acid and ibuprofen in aqueous solution at 298 K

    International Nuclear Information System (INIS)

    Graphical abstract: Complexation forces acting in the association between natural and modified α- and β-cyclodextrins and acetylsalicylic acid (aspirin) or ibuprofen are examined through the analysis of the thermodynamic parameters obtained by isothermal calorimetry. Highlights: ► A calorimetric method is reported to study the association of natural and substituted cyclodextrins with acetylsalicylic acid and ibuprofen. ► The study aims to propose a hypothesis about the forces involved in the interaction. That can be useful for designing new cyclodextrins having suitable characteristics to include specific drugs. ► Enthalpic and entropic contributions on the association are discussed. The differences in the cavity dimensions of the cyclodextrins determine the values of the thermodynamic properties to be very different. - Abstract: Thermodynamic parameters for the association of natural and substituted α-, β-, and γ-cyclodextrins with acetylsalicylic acid, salicylic acid and ibuprofen have been determined by isothermal titration calorimetry. Analysis of the data shows that complexes form, all having 1:1 stoichiometry. The shape-matching between the host and guest is the factor determining the values of the thermodynamic quantities. In the case of the smallest cyclodextrin interacting with acetylsalicylic acid and salicylic acid, the parameters indicate that hydrophobic interactions play the major role. Association occurs through the shallow inclusion of the benzene ring into the cavity. In the case of substituted β-cyclodextrins, instead, inclusion of the benzene ring is deeper and the tight fitting of the guest molecule to the cavity makes the enthalpy and entropy to be both negative. Ibuprofen interacts through its isobutyl group: the values of the association constants are very high for β-cyclodextrins as determined by the large and positive entropies due to the relaxation of water molecules from the cavity and the hydration spheres of the interacting

  20. Thermodynamics of inclusion complexes of natural and modified cyclodextrins with acetylsalicylic acid and ibuprofen in aqueous solution at 298 K

    Energy Technology Data Exchange (ETDEWEB)

    Castronuovo, Giuseppina, E-mail: giuseppina.castronuovo@unina.it [Department of Chemistry, University Federico II of Naples, Complesso Universitario a Monte S. Angelo, via Cintia, 80126 Naples (Italy); Niccoli, Marcella [Department of Chemistry, University Federico II of Naples, Complesso Universitario a Monte S. Angelo, via Cintia, 80126 Naples (Italy)

    2013-04-10

    Graphical abstract: Complexation forces acting in the association between natural and modified α- and β-cyclodextrins and acetylsalicylic acid (aspirin) or ibuprofen are examined through the analysis of the thermodynamic parameters obtained by isothermal calorimetry. Highlights: ► A calorimetric method is reported to study the association of natural and substituted cyclodextrins with acetylsalicylic acid and ibuprofen. ► The study aims to propose a hypothesis about the forces involved in the interaction. That can be useful for designing new cyclodextrins having suitable characteristics to include specific drugs. ► Enthalpic and entropic contributions on the association are discussed. The differences in the cavity dimensions of the cyclodextrins determine the values of the thermodynamic properties to be very different. - Abstract: Thermodynamic parameters for the association of natural and substituted α-, β-, and γ-cyclodextrins with acetylsalicylic acid, salicylic acid and ibuprofen have been determined by isothermal titration calorimetry. Analysis of the data shows that complexes form, all having 1:1 stoichiometry. The shape-matching between the host and guest is the factor determining the values of the thermodynamic quantities. In the case of the smallest cyclodextrin interacting with acetylsalicylic acid and salicylic acid, the parameters indicate that hydrophobic interactions play the major role. Association occurs through the shallow inclusion of the benzene ring into the cavity. In the case of substituted β-cyclodextrins, instead, inclusion of the benzene ring is deeper and the tight fitting of the guest molecule to the cavity makes the enthalpy and entropy to be both negative. Ibuprofen interacts through its isobutyl group: the values of the association constants are very high for β-cyclodextrins as determined by the large and positive entropies due to the relaxation of water molecules from the cavity and the hydration spheres of the interacting

  1. Kinetics, equilibrium and thermodynamic studies of Mn (II) biosorption from aqueous solution onto pleurotus ostreatus

    International Nuclear Information System (INIS)

    Biosorption of Mn (II) from aqueous solution by P. ostreatus was investigated at different concentrations, pH and temperature. The close agreement between the experimental and theoretical biosorption capacity confirmed that Pseudo 2nd order equation is best fitted to the present experimental data. The biosorption capacity of P. ostreatus was observed to be dependent upon the pH and temperature of adsorption system. The values of biosorption maxima (Xm) and binding energy constant (Kb) were observed to decrease with rise in temperature in the range of 298 - 323K. The negative values of delta G and delta H showed the process of Mn (II) biosorption onto P. ostreatus is spontaneous and exothermic respectively. Similarly, t he values of isosteric heat of biosorption ( ) were decreased with increase in surface coverage (?) which indicated that the surface of the P. ostreatus is energetically heterogeneous in nature. (author)

  2. Thermodynamics and kinetics of adsorption of dyes from aqueous media onto alumina

    International Nuclear Information System (INIS)

    Use of alumina for the removal of industrially important dyes namely, methylene blue, methyl blue, bromophenol blue, malachite green, eriochrome black-T, phenol red and methyl violet from aqueous media at different shaking times, temperatures and pH values has been investigated. The adsorption data was fitted to both the pseudo-first-order and pseudo-second-order kinetic models and calculated values of amount adsorbed at equilibrium (q/sub e/) by pseudo-second-order equations were found to be in good agreement with the experimental values. The negative values of delta H and delta G indicates that the adsorption is exothermic and spontaneous, respectively. The adsorption data was fitted to Freundlich, B.E.T., Dubinin-Radushevich (D-R) and Langmuir isotherms and their corresponding adsorption parameters for each were calculated. The dyes were found to be chemisorbed onto alumina. (author)

  3. Dielectric properties of aqueous solutions of holmium formates

    International Nuclear Information System (INIS)

    SHF-dielectric properties in the range of free-quenches 7-23.5 GHz and electric conductivity of aqueous solutions of holmium formates in the temperature range from 10 to 40 deg C were studied. Parameters of the process of dipole relaxation of water molecules: static dielectric constant, relaxation time and parameters of relaxation time distribution have been ascertained. Activation characteristics of the dipole relaxation and specific electric conductivity have been calculated. The change in the structural-kinetic state of water H-bond net in solution under the action of Ho3+ and HCOO- ions is considered on the basis of the data obtained. 10 refs., 2 figs.; 3 tabs

  4. THERMODYNAMIC STUDY OF NUCLEATION PROPERTY OF NUCLEATING AGENT

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    It is deduced from thermodynamic relations and confirm ed by experiment results that the nucleation rate and nucleation temperature o f nucleating agents in the glass are dependent upon their melting entropy ΔSm melting temperature Tm and crystal-type transition in terms of some mathemati cal expressions.

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

    Energy Technology Data Exchange (ETDEWEB)

    Rao, Linfeng; Tian, Guoxin

    2009-12-21

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

  6. 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.

  7. Examination of rheological properties of aqueous solutions of sodium caseinate

    Directory of Open Access Journals (Sweden)

    Jolanta Gawałek

    2012-12-01

    Full Text Available Application of sodium caseinate as a functional additive in manufacturing processes requires production of its concentrated aqueous solutions which, in industrial conditions, presents a number of difficulties. In order to develop an effective and optimal industrial process of mixing – manufacturing a concentrated solution of sodium caseinate, it is essential to know rheological properties in a definite range of concentrations changing in the course of the dissolving process. The material for investigations was typical commercial sodium caseinate in the form of dry powder manufactured in Poland from acid casein using the method of extrusion. The objective of the undertaken empirical studies was the assessment of the impact of the concentration on rheological properties of sodium caseinate concentrates. Investigations were carried out for five concentrates manufactured in a mixer equipped in a mechanical agitator at concentrations ranging X (% Î (2.5¸12.5 and changing mass proportions of sodium caseinate in the aqueous solution as follows: GS/G (kgS·kg-1 = 0.025. On the basis of the obtained research results, classical flow curves were plotted for individual concentrates. The determined values of viscosity and density of the examined solutions were correlated in the form of h = f(GS/G and r = f(GS/G dependencies which were used during the determination of classical characteristics of mixing forces essential for the assessment of energetic expenditures required to manufacture concentrates in a mixer equipped in a mechanical agitator. The density of the examined concentrates increased in a way directly proportional, while the dynamic viscosity coefficient increased exponentially together with the increase of sodium caseinate concentration. Sodium caseinate concentrates exhibited Newtonian character in the examined range of concentrations.

  8. First-principles study of structural, elastic, electronic, vibrational and thermodynamic properties of UN

    International Nuclear Information System (INIS)

    The structural, elastic, electronic, phonon and thermodynamic properties of UN are studied by density functional theory (DFT) within local-density approximation (LDA) and generalized gradient approximation (GGA), and GGA + U. The GGA calculations of the ground state structural and elastic properties of UN show an overall better agreement with experimental data compared to LDA or GGA + U. The melting temperature of UN (Tm) is estimated from the calculated elastic constant, with GGA predicting Tm = 2944 ± 300 K, in excellent agreement with experimental data. The calculated phonon dispersions of UN agree well with the low temperature measurements. Furthermore, the thermodynamic properties of UN are studied using quasiharmonic approximation by including both lattice vibrational and thermal electronic contributions. The predicted thermodynamic properties, such as enthalpy, entropy, Gibbs energy, heat capacity and thermal expansion coefficient, agree well with experimental data. The derived thermodynamic functions of UN are useful to the thermodynamic modeling of phase stabilities in UN-based materials. This study shows that the thermal electronic energy and entropy due to U 5f electrons are important to describe the free energy of UN, due to the metallic character of UN. The calculated thermodynamic properties also suggest that the anharmonic effects are less important in UN even at high-temperature

  9. A study of the behaviour of ampicillin in aqueous solution and thermodynamic characterization of its aggregation

    Science.gov (United States)

    Besada, Lina; Martinez-Landeira, Pablo; Seoane, Laura; Prieto, Gerardo; Sarmiento, Felix; Ruso, Juan M.

    The aggregation of ampicillin in water has been examined by conductivity measurements over the temperature range 288.15-313.15 K and light scattering. These measurements indicate the formation of two critical concentrations over the range 0-0.35 mol kg -1 . Aggregation number and effective aggregate charge were calculated from the static light scattering data according to the Anacker and Westwell treatment. Thermodynamic parameters of aggregate formation were obtained from a form of the mass action model applicable to systems of low aggregation number. This method was applied at both critical concentrations. A valence of one was used for the monomers present in the first equilibrium. The second equilibrium was between aggregates of two different sizes, in this case, the valence of the aggregates being the effective charge calculated from the Anacker and Westwell treatment. Experimental results show that free energies of micellization for ampicillin are higher for the first critical concentration and in the same range, but lower than for other penicillins. The enthalpies of micellization become negative when the temperature is increased, but the variation is three times greater for the first critical concentration than for the second.

  10. Adsorption of cadmium from aqueous solution onto untreated coffee grounds: Equilibrium, kinetics and thermodynamics

    International Nuclear Information System (INIS)

    Adsorption can be used as a cost effective and efficient technique for the removal of toxic heavy metals from wastewater. Waste materials with no further treatment such as coffee grounds from cafeterias may act as adsorbents for the removal of cadmium. Batch kinetic and equilibrium experiments were conducted to study the effects of contact time, adsorbent dose, initial pH, particle size, initial concentration of cadmium and temperature. Three adsorption isotherm models namely, Langmuir, Freundlich and Dubinin-Radushkevich were used to analyse the equilibrium data. The Langmuir isotherm which provided the best correlation for Cd2+ adsorption onto coffee grounds, shows that the adsorption was favourable and the adsorption capacity found was equal to 15.65 mg g-1. Thermodynamic parameters were evaluated and the adsorption was exothermic. The equilibrium was achieved less than 120 min. The adsorption kinetic data was fitted with first and second order kinetic models. Finally it was concluded that the cadmium adsorption kinetic onto coffee grounds was well fitted by second order kinetic model rather than first order model. The results suggest that coffee grounds have high possibility to be used as effective and economical adsorbent for Cd2+ removal.

  11. Thermodynamic approach of the poly-azine - f element ions interaction in aqueous conditions

    International Nuclear Information System (INIS)

    2-Amino-4,6-di-(pyridine-2-yl)-1,3,5-triazine (Adptz) was considered as a model compound for selective aromatic nitrogen extractants (poly-azines) of minor actinides. Thermodynamic data ( ΔG0, ΔH0, ΔS0) were systematically acquired for the complexation of lanthanide(III) ions as well as yttrium(III) and americium(III) in hydro-alcoholic medium. Two complementary experimental approaches were followed. Stability constants for the formation of the 1:1 complexes were evaluated from UV-visible spectrophotometry titration experiments, whereas enthalpies and entropies of reaction were obtained consistently from either temperature dependence experiments or micro-calorimetry. The interaction of Adptz with lanthanide(III) and yttrium(III) ions was found to be essentially ionic and dependent upon the hydration and size of the ion. As for americium(III) ion, stability constant and enthalpy of complexation was significantly larger. This was attributed to a partial electronic transfer from the ligand to empty orbitals of the cation. DFT calculations support this interpretation. (authors)

  12. Adsorption of cadmium from aqueous solution onto untreated coffee grounds: Equilibrium, kinetics and thermodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Azouaou, N., E-mail: azouaou20@yahoo.fr [Laboratory of Reaction Genius, Faculty of Mechanical and Processes Genius, University of Sciences and Technology Houari - Boumediene, USTHB, BP no 32 El Alia bab ezzouar, 16111 Algiers (Algeria); Sadaoui, Z. [Laboratory of Reaction Genius, Faculty of Mechanical and Processes Genius, University of Sciences and Technology Houari - Boumediene, USTHB, BP no 32 El Alia bab ezzouar, 16111 Algiers (Algeria); Djaafri, A. [Central laboratory, SEAAL, 97 Parc ben omar, Kouba, Algiers (Algeria); Mokaddem, H. [Laboratory of Reaction Genius, Faculty of Mechanical and Processes Genius, University of Sciences and Technology Houari - Boumediene, USTHB, BP no 32 El Alia bab ezzouar, 16111 Algiers (Algeria)

    2010-12-15

    Adsorption can be used as a cost effective and efficient technique for the removal of toxic heavy metals from wastewater. Waste materials with no further treatment such as coffee grounds from cafeterias may act as adsorbents for the removal of cadmium. Batch kinetic and equilibrium experiments were conducted to study the effects of contact time, adsorbent dose, initial pH, particle size, initial concentration of cadmium and temperature. Three adsorption isotherm models namely, Langmuir, Freundlich and Dubinin-Radushkevich were used to analyse the equilibrium data. The Langmuir isotherm which provided the best correlation for Cd{sup 2+} adsorption onto coffee grounds, shows that the adsorption was favourable and the adsorption capacity found was equal to 15.65 mg g{sup -1}. Thermodynamic parameters were evaluated and the adsorption was exothermic. The equilibrium was achieved less than 120 min. The adsorption kinetic data was fitted with first and second order kinetic models. Finally it was concluded that the cadmium adsorption kinetic onto coffee grounds was well fitted by second order kinetic model rather than first order model. The results suggest that coffee grounds have high possibility to be used as effective and economical adsorbent for Cd{sup 2+} removal.

  13. Adsorption of cadmium from aqueous solution onto untreated coffee grounds: equilibrium, kinetics and thermodynamics.

    Science.gov (United States)

    Azouaou, N; Sadaoui, Z; Djaafri, A; Mokaddem, H

    2010-12-15

    Adsorption can be used as a cost effective and efficient technique for the removal of toxic heavy metals from wastewater. Waste materials with no further treatment such as coffee grounds from cafeterias may act as adsorbents for the removal of cadmium. Batch kinetic and equilibrium experiments were conducted to study the effects of contact time, adsorbent dose, initial pH, particle size, initial concentration of cadmium and temperature. Three adsorption isotherm models namely, Langmuir, Freundlich and Dubinin-Radushkevich were used to analyse the equilibrium data. The Langmuir isotherm which provided the best correlation for Cd(2+) adsorption onto coffee grounds, shows that the adsorption was favourable and the adsorption capacity found was equal to 15.65 mg g(-1). Thermodynamic parameters were evaluated and the adsorption was exothermic. The equilibrium was achieved less than 120 min. The adsorption kinetic data was fitted with first and second order kinetic models. Finally it was concluded that the cadmium adsorption kinetic onto coffee grounds was well fitted by second order kinetic model rather than first order model. The results suggest that coffee grounds have high possibility to be used as effective and economical adsorbent for Cd(2+) removal. PMID:20817346

  14. Adsorption of methyl orange from aqueous solution by aminated pumpkin seed powder: Kinetics, isotherms, and thermodynamic studies.

    Science.gov (United States)

    Subbaiah, Munagapati Venkata; Kim, Dong-Su

    2016-06-01

    Present research discussed the utilization of aminated pumpkin seed powder (APSP) as an adsorbent for methyl orange (MO) removal from aqueous solution. Batch sorption experiments were carried to evaluate the influence of pH, initial dye concentration, contact time, and temperature. The APSP was characterized by using Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). The experimental equilibrium adsorption data were fitted using two two-parameter models (Langmuir and Freundlich) and two three-parameter models (Sips and Toth). Langmuir and Sips isotherms provided the best model for MO adsorption data. The maximum monolayer sorption capacity was found to be 200.3mg/g based on the Langmuir isotherm model. The pseudo-first-order and pseudo-second-order model equations were used to analyze the kinetic data of the adsorption process and the data was fitted well with the pseudo-second-order kinetic model (R(2)>0.97). The calculated thermodynamic parameters such as ΔG(0), ΔH(0) and ΔS(0) from experimental data showed that the sorption of MO onto APSP was feasible, spontaneous and endothermic in the temperature range 298-318K. The FTIR results revealed that amine and carboxyl functional groups present on the surface of APSP. The SEM results show that APSP has an irregular and porous surface which is adequate morphology for dye adsorption. Desorption experiments were carried to explore the feasibility of adsorbent regeneration and the adsorbed MO from APSP was desorbed using 0.1M NaOH with an efficiency of 93.5%. Findings of the present study indicated that APSP can be successfully used for removal of MO from aqueous solution. PMID:26921544

  15. Aqueous dissolution, solubilities and thermodynamic stabilities of common aluminosilicate clay minerals: Kaolinite and smectites

    Science.gov (United States)

    May, Howard M.; Klnniburgh, D.G.; Helmke, P.A.; Jackson, M.L.

    1986-01-01

    Determinations of the aqueous solubilities of kaolinite at pH 4, and of five smectite minerals in suspensions set between pH 5 and 8, were undertaken with mineral suspensions adjusted to approach equilibrium from over- and undersaturation. After 1,237 days, Dry Branch, Georgia kaolinite suspensions attained equilibrium solubility with respect to the kaolinite, for which Keq = (2.72 ?? 0.35) ?? 107. The experimentally determined Gibbs free energy of formation (??Gf,2980) for the kaolinite is -3,789.51 ?? 6.60 kj mol-1. Equilibrium solubilities could not be determined for the smectites because the composition of the solution phase in the smectite suspensions appeared to be controlled by the formation of gibbsite or amorphous aluminum hydroxide and not by the smectites, preventing attempts to determine valid ??Gf0 values for these complex aluminosilicate clay minerals. Reported solubility-based ??Gf0 determinations for smectites and other variable composition aluminosilicate clay minerals are shown to be invalid because of experimental deficiencies and of conceptual flaws arising from the nature of the minerals themselves. Because of the variable composition of smectites and similar minerals, it is concluded that reliable equilibrium solubilities and solubility-derived ??Gf0 values can neither be rigorously determined by conventional experimental procedures, nor applied in equilibriabased models of smectite-water interactions. ?? 1986.

  16. Textile dye removal from aqueous solutions by malt bagasse: Isotherm, kinetic and thermodynamic studies.

    Science.gov (United States)

    Fontana, Klaiani B; Chaves, Eduardo S; Sanchez, Jefferson D S; Watanabe, Erica R L R; Pietrobelli, Juliana M T A; Lenzi, Giane G

    2016-02-01

    The biosorption of orange solimax TGL 182% (OS-TGL) textile dye onto new and low cost biossorbent (malt bagasse) in aqueous solutions was investigated. The malt bagasse was characterized by Fourier transform infrared spectroscopy and specific surface area (BET method).Batch biosorption experiments were conducted in order to determine the following parameters: particles size, pH, agitation speed, temperature, contact time, biomass dosage, influence of the ionic strength and, finally, the influence of other textile dye on the OS-TGL biosorption. The optimum conditions for OS-TGL removal were obtained at pH 1.5, agitation speed of 150rpm, contact time of 180min and biomass dosage 2, 8gL(-1). The results show that the kinetics of biosorption followed a pseudo-second-order model and by increasing the temperature from 293 up to 313K, the biosorption capacity was improved. The Langmuir model showed better fit and the estimated biosorption capacity was 23.2mgg(-1). The negative values of Gibbs free energy, ΔG°, and positive value of enthalpy, ΔH°, confirm the spontaneous nature and endothermic character of the biosorption process. The results of the ionic strength effect indicated that the biosorption process under study had a strong tolerance in high salt concentrations. The removal capacity (>95%) was not affected with the presence of other textile dyes. PMID:26590694

  17. Speciation of phytate ion in aqueous solution Thermodynamic parameters for protonation in NaCl

    International Nuclear Information System (INIS)

    Phytate protonation enthalpies and entropies were determined by direct calorimetric titrations, in sodium chloride aqueous media at different ionic strengths (0.1≤I/mol L-1≤1) and at t=25 deg. C. Only the first seven protonation steps were taken into account, since the remaining five protons of phytic acid could be considered as 'strongly acidic' (log KiH≤1, 8≤i≤12). The analysis of results evidenced slight variations among enthalpy and entropy values, for the same protonation step (i), at different ionic strengths. TΔSi values for each protonation step are significantly higher than the corresponding enthalpy changes, revealing the entropic nature of the bond involved in phytate protonation. The enthalpy changes for phytate protonation generally increase for each protonation step, as typical for phosphate ligands. Dependence on ionic strength for both log KiH and ΔHi was taken into account by Specific ion Interaction Theory (SIT). Useful predictive relationships for the dependence of TΔS on ΔG and on protonation step 'i' were proposed

  18. Melanoidin Removal Mechanism in An Aqueous Adsorption System: An Equilibrium, Kinetic and Thermodynamic Study.

    Science.gov (United States)

    Nunes, Diego L; Oliveira, Leandro S; Franca, Adriana S

    2015-01-01

    Melanoidins are colored products that can be found in food and drinks, formed by Maillard reactions. Sometimes these compounds are considered undesirable in certain food products, because they impart a brownish color and must be removed. An overview of recent patents related to melanoidin removal indicates that it can be performed by chemical/biological degradation or by adsorption processes. Therefore, in the present study, the adsorption mechanism for synthetic melanoidin removal from aqueous solutions was studied using different Raphanus sativus press-cake sorbents, with the precursor material being carbonized in a microwave oven, either with direct heating or after a chemical activation process with phosphoric acid, nitric acid or potassium hydroxide. Physical and chemical modifications were evaluated by FTIR, pHPZC, thermogravimetry and BET. The adsorption kinetics was better described by a pseudo-second order model for all activated carbons (ACs). Evaluation of the diffusion process showed dependence on the initial melanoidin concentration due to the wide range of sizes of the adsorbed molecules. The equilibrium data were best fitted by the Langmuir model for the acid-treated AC and by the Freundlich model for the base-treated and non-chemically treated ACs. Melanoidin adsorption was characterized as a spontaneous, favorable and endothermic process involving hydrogen bonds and π-π interactions between the adsorbents surfaces and the adsorbed molecules. PMID:26013772

  19. Speciation of phytate ion in aqueous solution Thermodynamic parameters for protonation in NaCl

    Energy Technology Data Exchange (ETDEWEB)

    De Stefano, Concetta; Milea, Demetrio; Sammartano, Silvio

    2004-12-01

    Phytate protonation enthalpies and entropies were determined by direct calorimetric titrations, in sodium chloride aqueous media at different ionic strengths (0.1{<=}I/mol L{sup -1}{<=}1) and at t=25 deg. C. Only the first seven protonation steps were taken into account, since the remaining five protons of phytic acid could be considered as 'strongly acidic' (log K{sub i}{sup H}{<=}1, 8{<=}i{<=}12). The analysis of results evidenced slight variations among enthalpy and entropy values, for the same protonation step (i), at different ionic strengths. T{delta}S{sub i} values for each protonation step are significantly higher than the corresponding enthalpy changes, revealing the entropic nature of the bond involved in phytate protonation. The enthalpy changes for phytate protonation generally increase for each protonation step, as typical for phosphate ligands. Dependence on ionic strength for both log K{sub i}{sup H} and {delta}H{sub i} was taken into account by Specific ion Interaction Theory (SIT). Useful predictive relationships for the dependence of T{delta}S on {delta}G and on protonation step 'i' were proposed.

  20. Thermodynamic properties of amphiphilic antidepressant drug citalopram HBr

    International Nuclear Information System (INIS)

    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)

  1. Thermodynamic properties of dysprosium from 7 to 300 K

    International Nuclear Information System (INIS)

    The heat capacity of high-purity dysprosium was measured over the temperature range 7 to 300 K by adiabatic calorimetry. Results of mass-spectroscopic and gas analyses as well as the ratio of resistivities R(300 K)/R(4.2 K) approx. = 200 confirmed the high quality of the sample. Values of thermodynamic functions have been calculated: Csub(p)(T), S0(T), (H0(T)-H0(0)), and -(G0(T)-H0(0))/T at T = 298.15 K are respectively 27.73 J.K-1.mol-1, 75.55 J.K-1.mol-1, 8973 J.mol-1, and 45.45 J.K-1. mol-1. The phase transitions in dysprosium were found to be at 92.1 K and at 180.2 K. The influence of the purity of a sample on the thermodynamic functions is discussed. (author)

  2. Biosorption of total chromium from aqueous solution by red algae (Ceramium virgatum): Equilibrium, kinetic and thermodynamic studies

    International Nuclear Information System (INIS)

    This study focused on the biosorption of total chromium onto red algae (Ceramium virgatum) biomass from aqueous solution. Experimental parameters affecting biosorption process such as pH, contact time, biomass dosage and temperature were studied. Langmuir, Freundlich and Dubinin-Radushkevich (D-R) models were applied to describe the biosorption isotherms. Langmuir model fitted the equilibrium data better than the Freundlich isotherm. The biosorption capacity of C. virgatum biomass for total chromium was found to be 26.5 mg/g at pH 1.5 and 10 g/L biomass dosage, 90 min equilibrium time and 20 deg. C. From the D-R isotherm model, the mean free energy was calculated as 9.7 kJ/mol, indicating that the biosorption of total chromium was taken place by chemisorption. The calculated thermodynamic parameters (ΔGo, ΔHoand ΔSo) showed that the biosorption of total chromium onto C. virgatum biomass was feasible, spontaneous and exothermic at 20-50 deg. C. Kinetic evaluation of experimental data showed that the biosorption processes of total chromium followed well pseudo-second-order kinetics

  3. Biosorption of 2,4-dichlorophenol from aqueous solution by Phanerochaete chrysosporium biomass: Isotherms, kinetics and thermodynamics

    International Nuclear Information System (INIS)

    The biosorption of 2,4-dichlorophenol (2,4-DCP) from aqueous solution on non-living mycelial pellets of Phanerochaete chrysosporium was studied with respect to pH, initial concentration of 2,4-DCP, temperature and pellet size. The fungal biomass exhibited the highest sorption capacity of 4.09 mg/g at an initial pH of 5.0, initial 2,4-DCP concentration of 50.48 mg/l, 25 deg. C and a pellet size of 1.0-1.5 mm in the investigated pH 2.0-11.0, initial concentrations of 5-50 mg/l, temperature 25-50 deg. C, and pellet size of 1.0-2.5 mm. The Freundlich model exhibited a slightly better fit to the biosorption data of 2,4-DCP than the Langmuir model. The biosorption of 2,4-DCP to biomass followed pseudo second-order adsorption kinetics. The second-order kinetic constants decreased with increasing temperature, and the apparent activation energy of biosorption was estimated to be -16.95 kJ/mol. The thermodynamic analysis indicates that the biosorption process was exothermic and that the adsorption of 2,4-DCP on P. chrysosporium might be physical in nature. Both intraparticle diffusion and kinetic resistances might affect the adsorption rate and that their relative effects varied with operation temperature in the biosorption of 2,4-DCP by mycelial pellets

  4. Biosorption of palladium(II) from aqueous solution by moss (Racomitrium lanuginosum) biomass: Equilibrium, kinetic and thermodynamic studies

    International Nuclear Information System (INIS)

    The biosorption potential of Racomitrium lanuginosum as aquatic moss biosorbent for the removal of Pd(II) from aqueous solution was investigated. The effects of pH, biomass dosage, contact time, and temperature on the biosorption processes were systematically studied. Experimental data were modeled by Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherms. Langmuir isotherm model (R2 = 0.994) fitted the equilibrium data better than the Freundlich isotherm model (R2 = 0.935). The monolayer biosorption capacity of R. lanuginosum biomass for Pd(II) was found to be 37.2 mg/g at pH 5. The mean free energy was calculated as 9.2 kJ/mol using the D-R isotherm model (R2 = 0.996). This result indicated that the biosorption of Pd(II) was taken place by chemical ion-exchange. The calculated thermodynamic parameters, ΔGo, ΔHo and ΔSo showed that the biosorption of Pd(II) on R. lanuginosum biomass was feasible, spontaneous and exothermic under examined conditions. Experimental data were also tested using the biosorption kinetic models. The results showed that the biosorption processes of Pd(II) on R. lanuginosum followed well pseudo-second-order kinetics at 20-50 deg. C (R2 = 0.999)

  5. Kinetics, equilibrium and thermodynamic studies on biosorption of Ag(I) from aqueous solution by macrofungus Pleurotus platypus

    Energy Technology Data Exchange (ETDEWEB)

    Das, Devlina [School of Biosciences and Technology, VIT University, Vellore, Tamil Nadu (India); Das, Nilanjana, E-mail: nilanjana00@lycos.com [School of Biosciences and Technology, VIT University, Vellore, Tamil Nadu (India); Mathew, Lazar [School of Biosciences and Technology, VIT University, Vellore, Tamil Nadu (India)

    2010-12-15

    Reports are available on silver binding capacity of some microorganisms. However, reports on the equilibrium studies on biosorption of silver by macrofungi are seldom known. The present study was carried out in a batch system using dead biomass of macrofungus Pleurotus platypus for the sorption of Ag(I). P. platypus exhibited the highest silver uptake of 46.7 mg g{sup -1} of biomass at pH 6.0 in the presence of 200 mg L{sup -1} Ag(I) at 20 deg. C. Kinetic studies based on fractional power, zero order, first order, pseudo-first order, Elovich, second order and pseudo-second order rate expressions have been carried out. The results showed a very good compliance with the pseudo-first order model. The experimental data were analyzed using two parameter isotherms (Langmuir, Freundlich, Dubinin-Radushkevich, Temkin and Halsey), three parameter isotherms (Redlich-Peterson, Sips, Khan, Koble-Corrigan, Hill, Toth, Radke-Prausmitz, Jossens, Langmuir-Freundlich), four parameter isotherms (Weber-van Vliet, Fritz-Schlunder, Baudu) and five parameter isotherm (Fritz-Schlunder). Thermodynamic parameters of the biosorption ({Delta}G, {Delta}H and {Delta}S) were also determined. The present study confirmed that macrofungus P. platypus may be used as a cost effective efficient biosorbent for the removal of Ag(I) ions from aqueous solution.

  6. Kinetics, equilibrium and thermodynamic studies on biosorption of Ag(I) from aqueous solution by macrofungus Pleurotus platypus

    International Nuclear Information System (INIS)

    Reports are available on silver binding capacity of some microorganisms. However, reports on the equilibrium studies on biosorption of silver by macrofungi are seldom known. The present study was carried out in a batch system using dead biomass of macrofungus Pleurotus platypus for the sorption of Ag(I). P. platypus exhibited the highest silver uptake of 46.7 mg g-1 of biomass at pH 6.0 in the presence of 200 mg L-1 Ag(I) at 20 deg. C. Kinetic studies based on fractional power, zero order, first order, pseudo-first order, Elovich, second order and pseudo-second order rate expressions have been carried out. The results showed a very good compliance with the pseudo-first order model. The experimental data were analyzed using two parameter isotherms (Langmuir, Freundlich, Dubinin-Radushkevich, Temkin and Halsey), three parameter isotherms (Redlich-Peterson, Sips, Khan, Koble-Corrigan, Hill, Toth, Radke-Prausmitz, Jossens, Langmuir-Freundlich), four parameter isotherms (Weber-van Vliet, Fritz-Schlunder, Baudu) and five parameter isotherm (Fritz-Schlunder). Thermodynamic parameters of the biosorption (ΔG, ΔH and ΔS) were also determined. The present study confirmed that macrofungus P. platypus may be used as a cost effective efficient biosorbent for the removal of Ag(I) ions from aqueous solution.

  7. Kinetics, isothermal and thermodynamics studies of electrocoagulation removal of basic dye rhodamine B from aqueous solution using steel electrodes

    Science.gov (United States)

    Adeogun, Abideen Idowu; Balakrishnan, Ramesh Babu

    2015-09-01

    Electrocoagulation was used for the removal of basic dye rhodamine B from aqueous solution, and the process was carried out in a batch electrochemical cell with steel electrodes in monopolar connection. The effects of some important parameters such as current density, pH, temperature and initial dye concentration, on the process, were investigated. Equilibrium was attained after 10 min at 30 °C. Pseudo-first-order, pseudo-second-order, Elovich and Avrami kinetic models were used to test the experimental data in order to elucidate the kinetic adsorption process; pseudo-first-order and Avrami models best fitted the data. Experimental data were analysed using six model equations: Langmuir, Freudlinch, Redlich-Peterson, Temkin, Dubinin-Radushkevich and Sips isotherms and it was found that the data fitted well with Sips isotherm model. The study showed that the process depends on current density, temperature, pH and initial dye concentration. The calculated thermodynamics parameters (Δ G^circ ,Δ H^circ {text{and}}Δ S{^circ } ) indicated that the process is spontaneous and endothermic in nature.

  8. Biosorption of total chromium from aqueous solution by red algae (Ceramium virgatum): Equilibrium, kinetic and thermodynamic studies

    Energy Technology Data Exchange (ETDEWEB)

    Sari, Ahmet [Department of Chemistry, Gaziosmanpasa University, 60250 Tokat (Turkey)], E-mail: asari@gop.edu.tr; Tuzen, Mustafa [Department of Chemistry, Gaziosmanpasa University, 60250 Tokat (Turkey)

    2008-12-30

    This study focused on the biosorption of total chromium onto red algae (Ceramium virgatum) biomass from aqueous solution. Experimental parameters affecting biosorption process such as pH, contact time, biomass dosage and temperature were studied. Langmuir, Freundlich and Dubinin-Radushkevich (D-R) models were applied to describe the biosorption isotherms. Langmuir model fitted the equilibrium data better than the Freundlich isotherm. The biosorption capacity of C. virgatum biomass for total chromium was found to be 26.5 mg/g at pH 1.5 and 10 g/L biomass dosage, 90 min equilibrium time and 20 deg. C. From the D-R isotherm model, the mean free energy was calculated as 9.7 kJ/mol, indicating that the biosorption of total chromium was taken place by chemisorption. The calculated thermodynamic parameters ({delta}G{sup o}, {delta}H{sup o}and {delta}S{sup o}) showed that the biosorption of total chromium onto C. virgatum biomass was feasible, spontaneous and exothermic at 20-50 deg. C. Kinetic evaluation of experimental data showed that the biosorption processes of total chromium followed well pseudo-second-order kinetics.

  9. Preparation of titanate nanoflower for sorption of 75Se(IV) radioisotope from aqueous solution. Equilibrium, kinetic and thermodynamic studies

    International Nuclear Information System (INIS)

    In this study, the adsorptive removal of selenium (IV) from aqueous solution by titanate nanoflower (TNF) was prepared via alkaline hydrothermal method. The morphology and crystal phase of the TNF were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscope (EDX), selected area electron diffraction (SAED), thermogravimetric analysis (TGA), fourier transform infrared spectroscopy (FTIR) and specific surface area. This study was conducted to determine the influence of various operating parameters such as pH, adsorbate weight, initial anion concentration, contact time and solution temperature on the adsorptive removal of selenium (IV). Equilibrium adsorption data were analyzed using Freundlich, Langmuir and Dubinin-Radushkevich (D-R) isotherm models. The results demonstrated that the adsorption was well described by the Langmuir adsorption isotherm with the maximum adsorption capacity up to 46.52 mg/g at pH 3.5. The adsorption of Se(IV) anions onto the surface of TNF may proceed through outer sphere electrostatic interactions and/or inner-sphere complexation interaction. The kinetic data indicated that the adsorption fit well with the pseudo-second-order kinetic model. The thermodynamic parameters implied that the adsorption process was spontaneous and endothermic in nature.

  10. Thermodynamic, kinetic and mechanistic investigations of Piperazine oxidation by Diperiodatocuprate(III) complex in aqueous alkaline medium

    Indian Academy of Sciences (India)

    Vijay P Pattar; Prashant A Magdum; Deepa G Patil; Sharanappa T Nandibewoor

    2016-03-01

    The kinetics of oxidation of piperazine by the copper complex, diperiodatocuprate(III) in alkaline medium was studied at 298 K, at an ionic strength of 2.0*10-2 mol dm-3. The reaction between piperazine and diperiodatocuprate(III) in aqueous alkaline medium exhibited 1:2 stoichiometry. The oxidation products were identified by UV-Visible, GC-MS and IR spectral studies. In the present study we have obtained different kinetic observations. The reaction exhibited unit order in case of diperiodatocuprate(III), while less than unit order with respect to piperazine. The addition of alkali and periodate retarded the rate of reaction. The effects of added products, ionic strength and dielectric constant on the rate of the reaction were also studied. The active species of diperiodatocuprate(III) in alkaline media is [Cu(OH)2(H3IO6)]-. The activation parameters with respect to the rate determining step and the thermodynamic quantities with respect to the equilibrium steps were evaluated and discussed. The plausible mechanism consistent with the experimental results was proposed and discussed in detail.

  11. Chemical relevance of the copper(II)— L-carnosine system in aqueous solution: A thermodynamic and spectrophotometric study

    Science.gov (United States)

    Daniele, Pier G.; Prenesti, Enrico; Zelano, Vincenzo; Ostacoli, Giorgio

    1993-08-01

    The copper(II)— L-carnosine (L -) system has been re-investigated in aqueous solution, at I = 0.1 mol dm -1, different temperatures (5⩽ t⩽45°C) and with metal to ligand ratios ranging from 3:1 to 1:3. Both potentiometry and visible spectrophotometry were employed. From an overall consideration of all experiments, [CuLH] 2+, [CuL] +, [CuLH -1]°, [Cu 2L 2H -2]° and [Cu 2LH -1] 2+ were recognized as the species which provide the best interpretation of experimental data. The complex formation constants, determined at different temperatures, allowed us to obtain reliable values of Δ H° and good estimates of Δ C° p. From visible spectrophotometric measurements, carried out at different pH and metal to ligand ratios, it was possible to calculate the electronic spectrum of each complex formed in solution. A structure is also proposed for each species, on the basis of thermodynamic and spectral results.

  12. Thermodynamic properties of barium uranoborate and its dihydrate

    International Nuclear Information System (INIS)

    The standard enthalpies of formation of crystalline Ba(BUO5)2 and Ba(BUO5)2 · 2H2O at 298.15 K were determined by reaction calorimetry. The temperature dependences of the heat capacities of these compounds were studied over the temperature range 7-340 K by adiabatic vacuum calorimetry, and their thermodynamic functions were determined. The standard entropies and Gibbs functions of formation of these compounds at 298.15 K were calculated

  13. 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.

  14. Thermodynamic properties of a quantum Hall anti-dot interferometer

    OpenAIRE

    Schreier, Sarah Levy; Stern, Ady; Rosenow, Bernd; Halperin, Bertrand I.

    2015-01-01

    We study quantum Hall interferometers in which the interference loop encircles a quantum anti-dot. We base our study on thermodynamic considerations, which we believe reflect the essential aspects of interference transport phenomena. We find that similar to the more conventional Fabry-Perot quantum Hall interferometers, in which the interference loop forms a quantum dot, the anti-dot interferometer is affected by the electro-static Coulomb interaction between the edge modes defining the loop....

  15. Reaction Kinetic Parameters and Surface Thermodynamic Properties of Cu2O Nanocubes

    Directory of Open Access Journals (Sweden)

    Xingxing Li

    2015-07-01

    Full Text Available Cuprous oxide (Cu2O nanocubes were synthesized by reducing Cu(OH2 in the presence of sodium citrate at room temperature. The samples were characterized in detail by field-emission scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy, X-ray powder diffraction, and N2 absorption (BET specific surface area. The equations for acquiring reaction kinetic parameters and surface thermodynamic properties of Cu2O nanocubes were deduced by establishment of the relations between thermodynamic functions of Cu2O nanocubes and these of the bulk Cu2O. Combined with thermochemical cycle, transition state theory, basic theory of chemical thermodynamics, and in situ microcalorimetry, reaction kinetic parameters, specific surface enthalpy, specific surface Gibbs free energy, and specific surface entropy of Cu2O nanocubes were successfully determined. We also introduced a universal route for gaining reaction kinetic parameters and surface thermodynamic properties of nanomaterials.

  16. The extended thermodynamic properties of Taub–NUT/Bolt–AdS spaces

    Directory of Open Access Journals (Sweden)

    Chong Oh Lee

    2014-11-01

    Full Text Available We investigate the extended thermodynamic properties of higher-dimensional Taub–NUT/Bolt–AdS spaces where a cosmological constant is treated as a pressure. We find a general form for thermodynamic volumes of Taub–NUT/Bolt–AdS black holes for arbitrary dimensions. Interestingly, it is found that the Taub–NUT–AdS metric has a thermodynamically stable range when the total number of dimensions is a multiple of 4 (4, 8, 12, …. We also explore their phase structure and find the first order phase transition holds for higher-dimensional cases.

  17. 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.

  18. Thermodynamics of the formation of the Ni2+-glycine-L-histidine complex in aqueous solutions at 298.15 K

    Science.gov (United States)

    Gorboletova, G. G.; Metlin, A. A.; Bychkova, S. A.

    2015-05-01

    The Ni2+-glycine-L-histidine system in aqueous solution at 298.15 K and ionic strengths of 0.2, 0.5, and 1.0 with potassium nitrate as the supporting electrolyte has been investigated calorimetrically. Standard thermodynamic characteristics (Δr H°, Δr G°, Δr S°) of complexation have been determined. The NiLY complex is highly stable with respect to decomposition into homoligand complexes.

  19. Corresponding-states principle and its practice thermodynamic, transport and surface properties of fluids

    CERN Document Server

    Xiang, Hong Wei

    2005-01-01

    The corresponding-states principle helps the understanding and calculating of thermodynamic, transport, and surface properties of substances in various states, required by our modern lifestyle. The Corresponding-States Principle and its Practice: Thermodynamic, Transport and Surface Properties of Fluids describes the origins and applications of the principle from a universal point of view with comparisons to experimental data where possible. It uses the universal theory to explain present theories. Emphasis is on the properties of pure systems, and the corresponding-states theory can also be e

  20. Thermodynamic investigation of several natural polyols (IV): Heat capacities and thermodynamic properties of adonitol

    International Nuclear Information System (INIS)

    Adonitol was investigated by adiabatic calorimetry (AC), differential scanning calorimetry (DSC), thermogravity analysis (TGA) and oxygen-bomb combustion calorimetry. The heat capacity was precisely measured in the temperature range from 78 to 400 K by means of a small sample automated adiabatic calorimeter. The melting temperature, the molar enthalpy and entropy of this transition were determined to be T = 369.08 ± 0.45 K, 36.42 ± 0.18 kJ mol-1 and 98.68 ± 0.49 J K-1 mol-1 respectively from the experimental Cp-T curve. The thermodynamic functions [HT0-H298.150] and [ST0-S298.150], were derived from the heat capacity data with an interval of 5 K. The standard molar enthalpy of combustion and formation of the compound have been determined to be ΔcHm0(C5H12O5,cr)=(-2562.4±1.3)kJmol-1 and ΔfHm0(C5H12O5,cr)=(-1120.1±1.5)kJmol-1 respectively by means of a precision oxygen-bomb combustion calorimeter at T = 298.15 K. The thermostability of the compound was further studied by DSC and TGA measurements.

  1. Ergodic properties and thermodynamic behavior of elementary reversible cellular automata. I. Basic properties

    International Nuclear Information System (INIS)

    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

  2. Thermodynamic properties and phase stability of nanocrystalline metals

    Institute of Scientific and Technical Information of China (English)

    SONG Xiaoyan; LI Lingmei; ZHANG Jiuxing

    2006-01-01

    The fundamental thermodynamic functions of enthalpy, entropy, and Gibbs free energy, as functions of the excess free volume at interfaces, temperature, and grain size, have been derived for single-phase metal nanocrystals. The model was applied to predict the thermal features of nano-grain boundaries and the characteristics of phase transformation in nanocrystalline metals, such as the transformation temperature and the critical grain size for phase transformation at a given temperature. The model predictions have been verified by experimental studies on the β-Co (→) α-Co phase transformation in nanocrystalline Co prepared by ball milling.

  3. Specific heat and thermodynamic properties of the cesium perchlorate

    International Nuclear Information System (INIS)

    The cesium perchlorate specific heat has been measured in a vacuum adiabatic microcalorimeter in the 10-365 K range. On the basis of the data obtained the thermodynamic functions are calculated. Csub(p)sup(0) (298.15 K) = 110.4+-0.2 J/Kxmol; S0 (298.15 K)=175.9+-0.5 J/Kxmol; H0 (298.15 K) - H0(0)=22280+-50 J/mol; - [G0 (289.15 K) - H0(0)]/T = 101.2+-0.2 J/Kxmol

  4. Benchmark thermodynamic properties of alkanediamines: Experimental and theoretical study

    International Nuclear Information System (INIS)

    Highlights: • Vapor pressures of 1,2-propanediamine and 2-methyl-1,2-propanediamine were measured. • Vaporization enthalpies were derived and compared with the literature. • Thermochemical data were tested for consistency using additivity rules and computations. • Thermodynamic functions of 1,2-alkanediamines were calculated. • Simple method to assess gas phase entropies based on the G3MP2 method is suggested. - Abstract: Vapor pressures of (dl)-1,2-propanediamine and 2-methyl-1,2-propanediamine were measured using the transpiration method. Molar enthalpies of vaporization were derived from the vapor pressure temperature dependence. Thermodynamic data on alkanediamines available in the literature were collected and treated uniformly. Consistency of the experimental data set for alkanediamines was evaluated with group-contribution and quantum-chemical methods. The standard molar entropy of formation and the standard molar Gibbs function of formation have been calculated. Vaporization and formation enthalpies of alkanediamines of benchmark quality are recommended for practical thermochemical calculations and validation of empirical and theoretical methods

  5. Models for the estimation of thermodynamic properties of layered double hydroxides: application to the study of their anion exchange characteristics

    OpenAIRE

    Bravo-Suárez Juan J.; Páez-Mozo Edgar A.; Oyama S. Ted

    2004-01-01

    Several models for the estimation of thermodynamic properties of layered double hydroxides (LDHs) are presented. The predicted thermodynamic quantities calculated by the proposed models agree with experimental thermodynamic data. A thermodynamic study of the anion exchange process on LDHs is also made using the described models. Tables for the prediction of monovalent anion exchange selectivities on LDHs are provided. Reasonable agreement is found between the predicted and the experimental mo...

  6. Models for the estimation of thermodynamic properties of layered double hydroxides: application to the study of their anion exchange characteristics

    Directory of Open Access Journals (Sweden)

    Bravo-Suárez Juan J.

    2004-01-01

    Full Text Available Several models for the estimation of thermodynamic properties of layered double hydroxides (LDHs are presented. The predicted thermodynamic quantities calculated by the proposed models agree with experimental thermodynamic data. A thermodynamic study of the anion exchange process on LDHs is also made using the described models. Tables for the prediction of monovalent anion exchange selectivities on LDHs are provided. Reasonable agreement is found between the predicted and the experimental monovalent anion exchange selectivities.

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

    Science.gov (United States)

    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.

  8. Thermodynamic properties and cloud droplet activation of a series of oxo-acids

    Science.gov (United States)

    Frosch, Mia; Platt, Stephen; Zardini, Alessandro; Bilde, Merete

    2010-05-01

    Submicron sized aerosol particles in the Earth's atmosphere influence visibility, human health, and global climate (IPCC, 2007). The organic mass fraction of the atmospheric aerosol has been estimated at 20-90% of the total aerosol mass mass (Kanakidou et al., 2005). Many of the organic species found in the particle phase in the atmosphere are produced via the oxidation of biogenic hydrocarbon emissions such as terpenes and sesquiterpenes (Hallquist et al. 2009). 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 (Bilde, 2003), and liquid chromatography/mass spectrometry (LC/MS). Generally, the presence of the oxo functional group causes the vapor pressure of the compounds to diminish by an order of magnitude with respect to the parent dicarboxylic acid, and it tends to increase the CCN activity. Dicarboxylic acids with an oxo-group in the β-position were found to decarboxylate in aqueous solution. IPCC: Climate Change (2007): The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, UK. Kanakidou, M., Seinfeld, J. H., Pandis, S. N., Barnes, I., Dentener, F. J., Facchini, M. C., Van Dingenen, R., Ervens, B., Nenes, A., Nielsen, C. J., Swietlicki, E., Putaud, J. P., Balkanski, Y., Fuzzi, S., Horth, J., Moortgat, G. K., Winterhalter, R., Myhre, C. E. L., Tsigaridis, K., Vignati, E., Stephanou, E. G., and Wilson, J (2005). Atmos

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

    CERN Document Server

    Naden, Levi N

    2015-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jian-Bao; HUANG Chao-Guang; LIU Zeng-Rong; SUN Jia-Rui; LI Ying

    2008-01-01

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

  11. Thermodynamic investigation of several natural polyols (I): Heat capacities and thermodynamic properties of xylitol

    International Nuclear Information System (INIS)

    The low-temperature heat capacity Cp,m0 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 Cp-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, Cp,m0(JK-1mol-1) =165.87+105.19x+1.8011x2-41.445x3-41.851x4+65.152x5+66.744x6,x=[T(K)-220] /140. In the temperature range of 370-390K, Cp,m0(JK-1mol-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-1 and 90.12+/-0.45JK-1mol-1, respectively. The standard thermodynamic functions (HT0-H298.150) and (ST0-S298.150), 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, ΔcHm0 (C5H12O5, cr)=(-2463.2+/-1.2)kJmol-1and ΔfHm0 (C5H12O5, cr)=(-1219.3+/-0.3)kJmol-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.

  12. Thermodynamic investigation of several natural polyols (I): Heat capacities and thermodynamic properties of xylitol

    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.

  13. Thermodynamic properties of a quantum Hall anti-dot interferometer

    Science.gov (United States)

    Levy Schreier, Sarah; Stern, Ady; Rosenow, Bernd; Halperin, Bertrand I.

    2016-02-01

    We study quantum Hall interferometers in which the interference loop encircles a quantum anti-dot. We base our study on thermodynamic considerations, which we believe reflect the essential aspects of interference transport phenomena. We find that similar to the more conventional Fabry-Perot quantum Hall interferometers, in which the interference loop forms a quantum dot, the anti-dot interferometer is affected by the electro-static Coulomb interaction between the edge modes defining the loop. We show that in the Aharonov-Bohm regime, in which effects of fractional statistics should be visible, is easier to access in interferometers based on anti-dots than in those based on dots. We discuss the relevance of our results to recent measurements on anti-dots interferometers.

  14. Crystal structure and thermodynamic properties of potassium antimony tungsten oxide

    Energy Technology Data Exchange (ETDEWEB)

    Knyazev, Aleksandr V., E-mail: knav@uic.nnov.ru [Nizhny Novgorod State University, Gagarin Prospekt 23/2, Nizhny Novgorod, 603950 (Russian Federation); Tananaev, Ivan G. [Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31 Leninsky prospect, Moscow GSP-1, 119991 (Russian Federation); Kuznetsova, Nataliya Yu.; Smirnova, Nataliya N.; Letyanina, Irene A.; Ladenkov, Igor V. [Nizhny Novgorod State University, Gagarin Prospekt 23/2, Nizhny Novgorod, 603950 (Russian Federation)

    2010-02-20

    In the present work potassium antimony tungsten oxide with pyrochlore structure is refined by the Rietveld method (space group Fd3m, Z = 8). The temperature dependences of heat capacity have been measured for the first time in the range from 7 to 370 K for this compound. The experimental data were used to calculate standard thermodynamic functions, namely the heat capacity C{sub p}{sup o}(T), enthalpy H{sup o}(T) - H{sup o}(0), entropy S{sup o}(T) - S{sup o}(0) and Gibbs function G{sup o}(T) - H{sup o}(0), for the range from T {yields} 0 to 370 K. The differential scanning calorimetry was applied to measure the incongruent melting temperature of compound under study. The high-temperature X-ray diffraction was used for the determining thermal expansion coefficients.

  15. Thermodynamic properties of pentalead tris(vanadate) chloride

    Energy Technology Data Exchange (ETDEWEB)

    Knyazev, A.V., E-mail: knyazevav@gmail.com [Nizhny Novgorod State University, Gagarin Prospekt 23/2, Nizhny Novgorod 603950 (Russian Federation); Bulanov, E.N.; Smirnova, N.N.; Kuznetsova, N.Yu.; Letyanina, I.A.; Pryamova, E.D. [Nizhny Novgorod State University, Gagarin Prospekt 23/2, Nizhny Novgorod 603950 (Russian Federation)

    2011-03-10

    Graphical abstract: - Abstract: In the present work the temperature dependences of pentalead tris(vanadate) chloride heat capacity have been measured for the first time in the range from 7 to 350 K. The experimental data were used to calculate standard thermodynamic functions, namely the heat capacity C{sub p} {sup o} (T), enthalpy H{sup o}(T) - H{sup o}(0), entropy S{sup o}(T) - S{sup o}(0) and Gibbs function G{sup o}(T) - H{sup o}(0), for the range from T {yields} 0 to 350 K. The differential scanning calorimetry in temperature interval 298-1473 K was applied to measure temperatures of phase transition and melting of compound under study. The high-temperature X-ray diffraction in range 298-1073 K was used for the determining thermal expansion coefficients.

  16. Thermodynamic properties of cyclohexanamines: Experimental and theoretical study

    Energy Technology Data Exchange (ETDEWEB)

    Verevkin, Sergey P., E-mail: sergey.verevkin@uni-rostock.de [Department of Physical Chemistry and Department “Science and Technology of Life, Light and Matter”, University of Rostock, Dr-Lorenz-Weg 1, Rostock D-18059 (Germany); Department of Physical Chemistry, Kazan Federal University, Kremlevskaya str. 18, 420008 Kazan (Russian Federation); Emeĺyanenko, Vladimir N. [Department of Physical Chemistry, Kazan Federal University, Kremlevskaya str. 18, 420008 Kazan (Russian Federation)

    2015-05-20

    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.

  17. Thermodynamic properties of cyclohexanamines: Experimental and theoretical study

    International Nuclear Information System (INIS)

    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

  18. The thermodynamic properties of Ba2SrUO6

    International Nuclear Information System (INIS)

    Standard formation enthalpy (-2940.0±8.5 kJ/mol) of the crystal Ba2SrUO6 was determined by the method of reaction calorimetry at 298.15 K. Specific heat was studied, and thermodynamic functions were calculated by the method of adiabatic calorimetry in the range of 8-330 K for the given compound. Its standard entropy (-558.6±2.1 J/(mol K)) and Gibbs formation function (-2773.5±9.0 kJ/mol) were calculated at 298.15 K. The reaction of the Ba2SrUO6 synthesis was shown to take place exothermic manner and through enthalpy contribution in the Gibbs function of the reaction

  19. Solution of D dimensional Dirac equation for coulombic potential using NU method and its thermodynamics properties

    Energy Technology Data Exchange (ETDEWEB)

    Cari, C., E-mail: cari@staff.uns.ac.id; Suparmi, A., E-mail: soeparmi@staff.uns.ac.id; Yunianto, M., E-mail: muhtaryunianto@staff.uns.ac.id; Husein, A. S. [Physics Department, Faculty of Mathematics and Science, SebelasMaret University, Jl. Ir. Sutami 36A Kentingan Surakarta 57126 (Indonesia)

    2016-02-08

    The analytical solution of Ddimensional Dirac equation for Coulombic potential is investigated using Nikiforov-Uvarov method. The D dimensional relativistic energy spectra are obtained from relativistic energy eigenvalue equation by using Mat Lab software.The corresponding D dimensional radial wave functions are formulated in the form of generalized Jacobi and Laguerre Polynomials. In the non-relativistic limit, the relativistic energy equation reduces to the non-relativistic energy which will be applied to determine some thermodynamical properties of the system. The thermodynamical properties of the system are expressed in terms of error function and imaginary error function.

  20. Solution of D dimensional Dirac equation for coulombic potential using NU method and its thermodynamics properties

    International Nuclear Information System (INIS)

    The analytical solution of Ddimensional Dirac equation for Coulombic potential is investigated using Nikiforov-Uvarov method. The D dimensional relativistic energy spectra are obtained from relativistic energy eigenvalue equation by using Mat Lab software.The corresponding D dimensional radial wave functions are formulated in the form of generalized Jacobi and Laguerre Polynomials. In the non-relativistic limit, the relativistic energy equation reduces to the non-relativistic energy which will be applied to determine some thermodynamical properties of the system. The thermodynamical properties of the system are expressed in terms of error function and imaginary error function

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

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Yuhua

    2012-11-02

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

  2. Applicability of four parameter formalisms in interpreting thermodynamic properties of binary systems

    Indian Academy of Sciences (India)

    S Acharya; J P Hajra

    2011-04-01

    The four parameter functions are generally considered to be adequate for representation of the thermodynamic properties for the strongly interacting binary systems. The present study involves a critical comparison in terms of applicability of the three well known four-parameter formalisms for the representation of the thermodynamic properties of binary systems. The study indicates that the derived values of the infinite dilution parameters based on the formalisms compare favourably with the computed data available in the literature. The standard deviations in terms of the partial and integral excess functions of all the models lie well within the experimental scatter of the computed data and coincide exactly with each other. The formalisms are useful in representation of the thermodynamic properties of most of the binary systems except for the Mg–Bi and Mg–In systems. In such systems, it appears that the additional compositional terms may be necessary for the formalisms for adequate description of behaviour of the systems. Since the derived values of the thermodynamic properties of all the formalisms match favourably over the entire compositional range for the systems as studied in the present research, any one of them may be used for adequate representation of the properties of the systems.

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

    Science.gov (United States)

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

    2015-10-01

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

  4. Substituent Effect on Infrared Spectra and Thermodynamic Properties of Polynitroamino Substituted Cyclopentane and Cyclohexane

    Institute of Scientific and Technical Information of China (English)

    Ling Qiua; Xue-dong Gong; He-ming Xiao

    2008-01-01

    Density functional theory method was employed to study the ffect of the nitroamino group as a substituent in cyclopentanc and cyclohexane, which usually construct polycyclic or caged nitramines. Based on the optimized molecular structures of two groups of monocyclic nitramines at the B3LYP/6-31G** level, the infrared (IR) spectra wcrc obtained and assigned by harmonic vibrational analysis. The ca]culated results agree reasonably with the available experimental data. According to the principles of statistic thermody-namics, thermodynamic properties were derived from the IR spectra, which were linearly corrclated with the number of nitroamino groups as well as the temperature. The contributions of nitroamino groups to thermodynamic properties are in accord with the group additivity.

  5. Thermodynamical properties of triangular quantum wires: entropy, specific heat, and internal energy

    Science.gov (United States)

    Khordad, R.

    2016-07-01

    In the present work, thermodynamical properties of a GaAs quantum wire with equilateral triangle cross section are studied. First, the energy levels of the system are obtained by solving the Schrödinger equation. Second, the Tsallis formalism is applied to obtain entropy, internal energy, and specific heat of the system. We have found that the specific heat and entropy have certain physically meaningful values, which mean thermodynamic properties cannot take any continuous value, unlike classical thermodynamics in which they are considered as continuous quantities. Maximum of entropy increases with increasing the wire size. The specific heat is zero at special temperatures. Specific heat decreases with increasing temperature. There are several peaks in specific heat, and these are dependent on quantum wire size.

  6. Thermophysical Properties of Aqueous Solutions Used as Secondary Working Fluids

    OpenAIRE

    Melinder, Åke

    2007-01-01

    Secondary working fluids (secondary refrigerants, heat transfer fluids, antifreezes, brines) have long been used in various indirect re-frigeration and heat pump systems. Aqueous solutions (water solu-tions) have long been used as single phase (liquid only) secondary working fluids for cooling in supermarkets, ice rinks, heat recovery systems, heat pumps and other applications. However, aqueous solutions are increasingly used also for freezers in supermarkets and other applications in low tem...

  7. Thermodynamic investigation of the ternary mixed aqueous electrolyte (MgCl2 + MgSO4) system by potentiometric method at T = 298.15 K

    International Nuclear Information System (INIS)

    Highlights: → In this study we investigated the thermodynamic properties of MgCl2 + MgSO4 + H2O. → The method used in this work was potentiometric method. → Mg-ISE and the Ag/AgCl electrodes used in this work had a good Nernst response. → The experimental results obeyed the Harned rule. → The Pitzer model could be used to describe this ternary system satisfactorily. - Abstract: This work reports the results of thermodynamic investigation of the ternary mixed-electrolyte system (MgCl2 + MgSO4 + H2O). The investigation was performed based on Pitzer ion interaction model by using the potentiometric technique at T = 298.15 K. The mean activity coefficients of MgCl2 in the mixed aqueous electrolyte system were determined on the galvanic cell without liquid junction of the type: Mg-ISE|MgCl2 (mA), MgSO4 (mB), H2O|Ag/AgCl over total ionic strengths from (0.001 to 8.000) mol . kg-1 for different series of salt ratio r (r=mMgCl2/mMgSO4=2.5,5.0,7.5,10.0,15.0 and pure MgCl2). The PVC based magnesium ion-selective electrode (Mg-ISE) and the Ag/AgCl electrode used in this work were made in our laboratory and had a reasonably good Nernst response. The experimental results obeyed the Harned rule, and the Pitzer model could be used to describe this ternary system satisfactorily. Pitzer ion-interaction parameters for mixed salts were determined for this system. Then, these parameters (θClSO4=0.0252±0.0042, ψMgClSO4=-0.0049±0.0003) were used to calculate the values of the mean activity coefficients of MgSO4, the osmotic coefficients of water (φ) and the excess Gibbs free energies of solution (GE) for the whole series of the studied electrolyte systems.

  8. Thermodynamical properties of Zr-based bulk metallic glasses

    Science.gov (United States)

    Gaur, Jitendra; Mishra, R. K.

    2015-11-01

    The temperature dependence of Gibb's free energy difference (ΔG), entropy difference (ΔS) and enthalpy difference (ΔH) between the undercooled melt and the corresponding equilibrium solid phases of bulk metallic glass (BMG) forming melts has been proved to be very useful in the study of their thermodynamical behavior. The present study is made by calculating ΔG, ΔS and ΔH in the entire temperature range Tm (melting temperature) to Tg (glass transition temperature) for three Zr-based samples of BMGs: Zr57Cu15.4Ni12.6Al10Nb5, Zr41.2Ti13.8Ni10Cu12.5Be22.5 and Zr58.5Cu15.6Ni12.8Al10.3Nb2.8. The study is made on the basis of Taylor's series expansion and a comparative study is also performed between the present result and the result obtained in the framework of expansions proposed by earlier workers, and also with the experimental results. An attempt has also been made to study the glass forming ability for BMGs.

  9. Adsorption removal of Congo red from aqueous solution by polyhedral Cu{sub 2}O nanoparticles: Kinetics, isotherms, thermodynamics and mechanism analysis

    Energy Technology Data Exchange (ETDEWEB)

    Shu, Jinxia [Chemical Synthesis and Pollution Control Key Laboratory of Sichuan Province, College of Chemistry and Chemical Engineering, China West Normal University, Nanchong 637002 (China); Wang, Zhonghua, E-mail: zhwangs@163.com [Chemical Synthesis and Pollution Control Key Laboratory of Sichuan Province, College of Chemistry and Chemical Engineering, China West Normal University, Nanchong 637002 (China); Huang, Yijiang; Huang, Ni [Chemical Synthesis and Pollution Control Key Laboratory of Sichuan Province, College of Chemistry and Chemical Engineering, China West Normal University, Nanchong 637002 (China); Ren, Chunguang [Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192 (Japan); Zhang, Wei [College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China)

    2015-06-05

    Highlights: • Polyhedral Cu{sub 2}O NPs with rough surfaces were prepared by a one-pot sonochemical precipitation method. • The Cu{sub 2}O NPs show unprecedented adsorption capability toward Congo red. • CR adsorption onto Cu{sub 2}O is a spontaneous, endothermic and chemisorption process. • The Cu{sub 2}O adsorbent can be photocatalytically regenerated by visible light irradiation. - Abstract: Polyhedral cuprous oxide nanoparticles (Cu{sub 2}O NPs) with rough surfaces were prepared by a one-pot sonochemical precipitation method. The products were characterized by SEM, XRD, EDS, XPS, and UV–Vis DRS, respectively. The adsorption behavior of Congo red (CR) from aqueous solution onto the as-prepared Cu{sub 2}O NPs was systematically investigated. The equilibrium and kinetic studies suggested that the adsorption process followed Freundlich isotherm and pseudo-second order model, respectively. The as-prepared Cu{sub 2}O NPs exhibited remarkable adsorption properties toward CR. The maximum adsorption capacity at 20 °C was 3904 mg g{sup −1}, which was the highest reported value so far in adsorption removal of CR. Together with the evaluation of the thermodynamic parameters such as Gibbs free energy, enthalpy and entropy change, our results show that the adsorption of CR onto Cu{sub 2}O is a spontaneous, endothermic and chemisorption process. A putative interaction model between CR and Cu{sub 2}O NPs was proposed. Moreover, the Cu{sub 2}O adsorbent could be photocatalytically regenerated and reused without significant loss of its adsorption capability.

  10. Optimization, isotherm, kinetic and thermodynamic studies of Pb(II) ions adsorption onto N-maleated chitosan-immobilized TiO2 nanoparticles from aqueous media

    Science.gov (United States)

    Shaker, Medhat A.; Yakout, Amr A.

    2016-02-01

    Chitosan, CS was chemically engineered by maleic anhydride via simple protocol to produce N-maleated chitosan, MCS which immobilized on anatase TiO2 to synthesize novel eco-friendly nanosorbent (51 ± 3.8 nm), MCS@TiO2 for cost-effective and efficient removal of Pb(II) ions from aqueous media. The chemical structure, surface properties and morphology of MCS@TiO2 were recognized by FTIR, 1H NMR, XRD, TEM, DLS and zeta-potential techniques. The relations between %removal of Pb(II) and different analytical parameters such as solution acidity (pH), MCS@TiO2 dosage, time of contact and initial Pb(II) concentration were optimized using response surface methodology (RSM) and Box-Behnken design (BBD) statistical procedures. The fitting of the experimental data to four different isotherm models at optimized conditions was carried out by various statistical treatments including the correlation coefficient (r), coefficient of determination (r2) and non-linear Chi-square (χ2) test analyses which all confirm the suitability of Langmuir model to explain the adsorption isotherm data. Also, statistics predicted that the pseudo-second-order model is the optimum kinetic model among four applied kinetic models to closely describe the rate equation of the adsorption process. Thermodynamics viewed the adsorption as endothermic and feasible physical process. EDTA could release the sorbed Pb(II) ions from MCS@TiO2 with a recovery above 92% after three sorption-desorption cycles. The novel synthesized nanosorbent is evidenced to be an excellent solid phase extractor for Pb(II) ions from wastewaters.

  11. Optimization, isotherm, kinetic and thermodynamic studies of Pb(II) ions adsorption onto N-maleated chitosan-immobilized TiO₂ nanoparticles from aqueous media.

    Science.gov (United States)

    Shaker, Medhat A; Yakout, Amr A

    2016-02-01

    Chitosan, CS was chemically engineered by maleic anhydride via simple protocol to produce N-maleated chitosan, MCS which immobilized on anatase TiO2 to synthesize novel eco-friendly nanosorbent (51±3.8 nm), MCS@TiO2 for cost-effective and efficient removal of Pb(II) ions from aqueous media. The chemical structure, surface properties and morphology of MCS@TiO2 were recognized by FTIR, (1)H NMR, XRD, TEM, DLS and zeta-potential techniques. The relations between %removal of Pb(II) and different analytical parameters such as solution acidity (pH), MCS@TiO2 dosage, time of contact and initial Pb(II) concentration were optimized using response surface methodology (RSM) and Box-Behnken design (BBD) statistical procedures. The fitting of the experimental data to four different isotherm models at optimized conditions was carried out by various statistical treatments including the correlation coefficient (r), coefficient of determination (r(2)) and non-linear Chi-square (χ(2)) test analyses which all confirm the suitability of Langmuir model to explain the adsorption isotherm data. Also, statistics predicted that the pseudo-second-order model is the optimum kinetic model among four applied kinetic models to closely describe the rate equation of the adsorption process. Thermodynamics viewed the adsorption as endothermic and feasible physical process. EDTA could release the sorbed Pb(II) ions from MCS@TiO2 with a recovery above 92% after three sorption-desorption cycles. The novel synthesized nanosorbent is evidenced to be an excellent solid phase extractor for Pb(II) ions from wastewaters. PMID:26520475

  12. Thermodynamic Properties of a Reissner-Nordstr(o)m Quintessence Black Hole

    Institute of Scientific and Technical Information of China (English)

    WEI Yi-Huan; CHU Zhong-Hui

    2011-01-01

    The first law of thermodynamics for the three horizons of Reissner-Nordstr(o)m quintessence (RNQ) spacetime is obtained.For a general process of RNQ spacetime,the expressions for the radius changes of the three horizons are derived.When only mass changes,the heat fluxes through the three horizons are equivalent and no heat is left in the black hole region.Finally,a further discussion on the thermal properties of an RNQ black hole is given.Black holes satisfy the four laws of thermodynamics,which indicates a deep connection between gravity and thermodynamics,[1-4] where the entropy of black hole is proportional to the area of event horizon and the temperature of black hole is proportional to the surface gravity of event horizon.For a static and spherically symmetric spacetime,the field equation may be written as the first law of thermodynamics.[5-10]%The first law f thermodynamics for the three horizons of Reissner-Nordstrom quintessence (RNQ) spacetime is obtained. For a general process of RNQ spacetime, the expressions for the radius changes of the three horizons are derived. When only mass changes, the heat fluxes through the three horizons are equivalent and no heat is left in the black hole region. Finally, a further discussion on the thermal properties of an RNQ black hole is given.

  13. Differential Scanning Calorimetry for Determining the Thermodynamic Properties of Selected Honeys

    OpenAIRE

    Tomaszewska-Gras Jolanta; Bakier Sławomir; Goderska Kamila; Mansfeld Krzysztof

    2015-01-01

    Thermodynamic properties of selected honeys: glass transition temperature (Tg), the change in specifi c heat capacity (ΔCp), and enthalpy (ΔH) were analysed using differential scanning calorimetry (DSC) in relation to the composition i.e. water and sugar content. Glass transition temperatures (Tg) of various types of honey differed significantly (p

  14. 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.

  15. Phase diagram and thermodynamic properties of CuCl-UCl4 system

    International Nuclear Information System (INIS)

    Phase equilibria in the system CuCl-UCl4 have been examined. Basing upon the liquidus curve as well as fusion enthalpies of CuCl, UCl4 and 2CuCl.UCl4 checked or determined by cryometric method, the thermodynamic properties of the liquid phase in this system have been described. (author)

  16. A Survey of Thermodynamics and Transport Properties in Chemical Engineering Education in Europe and the USA

    Czech Academy of Sciences Publication Activity Database

    Ahlström, P.; Aim, Karel; Dohrn, R.; Elliott, R.; Fele-Žilnik, L.; Jackson, G.; Jaubert, J.-N.; Macedo, M.E.R.; Pokki, J.-P.; Reczey, K.; Victorov, A.; Economou, I.G.

    - : Omnipress, 2008, s. 148. ISBN N. [AIChE Annual Meeting 2008. Philadelphia, PA (US), 16.11.2008-21.11.2008] Institutional research plan: CEZ:AV0Z40720504 Keywords : thermodynamics * transport properties education * undergraduate and graduate programs Subject RIV: CF - Physical ; Theoretical Chemistry http://www.aiche.org/Conferences/AnnualMeeting/index.aspx

  17. 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...

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

    Science.gov (United States)

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

    1971-01-01

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

  19. Chemical constraints governing the origin of metabolism: the thermodynamic landscape of carbon group transformations under mild aqueous conditions

    Science.gov (United States)

    Weber, Arthur L.

    2002-01-01

    The thermodynamics of organic chemistry under mild aqueous conditions was examined in order to begin to understand its influence on the structure and operation of metabolism and its antecedents. Free energies (deltaG) were estimated for four types of reactions of biochemical importance carbon-carbon bond cleavage and synthesis, hydrogen transfer between carbon groups, dehydration of alcohol groups, and aldo-keto isomerization. The energies were calculated for mainly aliphatic groups composed of carbon, hydrogen, and oxygen. The energy values showed (1) that generally when carbon-carbon bond cleavage involves groups from different functional group classes (i.e., carboxylic acids, carbonyl groups, alcohols, and hydrocarbons), the transfer of the shared electron-pair to the more reduced carbon group is energetically favored over transfer to the more oxidized carbon group, and (2) that the energy of carbon-carbon bond transformation is primarily determined by the functional group class of the group that changes oxidation state in the reaction (i.e., the functional group class of the group that donates the shared electron-pair during cleavage, or that accepts the incipient shared electron-pair during synthesis). In contrast, the energy of hydrogen transfer between carbon groups is determined by the functional group class of both the hydrogen-donor group and the hydrogen-acceptor group. From these and other observations we concluded that the chemistry involved in the origin of metabolism (and to a lesser degree modern metabolism) was strongly constrained by (1) the limited redox-based transformation energy of organic substrates that is readily dissipated in a few energetically favorable irreversible reactions; (2) the energy dominance of a few transformation half-reactions that determines whether carbon-carbon bond transformation (cleavage or synthesis) is energetically favorable (deltaG +3.5 kcal/mol); and (3) the dependence of carbon group transformation energy on the

  20. Synthesis and aggregation properties of amphiphilic mono and bisadducts of fullerene in aqueous solution

    Institute of Scientific and Technical Information of China (English)

    Pu Zhang; Zhi Xin Guo; Shuang Lv

    2008-01-01

    New amphiphilic[60]fullerene monoadduet TPF and bisadducts BTPF were synthesized and well-characterized. Their aggregation properties in aqueous solution was investigated by UV-vis and TEM methods. In aqueous solution, monoadduct TPF forms irregularly shaped and some rod-like aggregates, whereas bisadducts BTPF gives spherical aggregates with diameters of 50-150 nm. It indicated that the aggregation properties of amphiphilic fullerene derivatives depend on the number of hydrophilic appendage on the C60 cage.

  1. Analytical thermodynamical properties of a two-dimensional electron gas in a magnetic field

    International Nuclear Information System (INIS)

    Analytical expressions for the thermodynamical properties of a two-dimensional electron gas in a perpendicular magnetic field are derived. This is accomplished by first deriving the general expression for the thermodynamical potential, and then employing this result to obtain the corresponding expression for the two-dimensional gas. The chemical potential and magnetization are studied as a function of temperature and magnetic field, and shown to be in agreement with prior work. It is also shown that the results are close to those obtained by assuming a Gaussian density of states for the Landau levels

  2. Thermodynamic Properties of Alloys of Iron and Silicon

    International Nuclear Information System (INIS)

    The Fe-Si phase diagram is complex. At 1000°K there are FeSi2(β) and FeSi phases and solid solutions of silicon in α and α' iron. EMF measurements were made on the electrochemical cells: Fe|Fe2+ , 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 FeSi2(β), FeSi and Fe3Si 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 FeSi2.33 (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)

  3. Low-Temperature Thermodynamic Properties of Superconducting Antiperovskite CdCNi_3

    Science.gov (United States)

    Szczȩśniak, R.; Durajski, A. P.; Skoczylas, K. M.; Herok, Ł.

    2016-06-01

    We investigate the thermodynamic parameters of the superconducting antiperovskite CdCNi_3 using the Eliashberg approach which is an excellent tool to the exact characterization of the conventional superconductors. In particular, we reproduce the measured superconducting transition temperature (T_C=3.2 K) for a high value of the Coulomb pseudopotential (μ ^{star }C=0.22). Then we determine the energy gap, the thermodynamic critical field and the specific heat for the superconducting and normal state. On this basis, we show that the thermodynamic properties of CdCNi_3 differ slightly from the prediction of the Bardeen-Cooper-Schrieffer theory, which means that CdCNi_3 is a medium-coupling superconductor in contrast to related strong-coupling MgCNi_3.

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

    Energy Technology Data Exchange (ETDEWEB)

    Cliff B. Davis

    2010-09-01

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

  5. Molecular Thermodynamic Modeling of Fluctuation Solution Theory Properties

    DEFF Research Database (Denmark)

    O’Connell, John P.; Abildskov, Jens

    2013-01-01

    Fluctuation Solution Theory provides relationships between integrals of the molecular pair total and direct correlation functions and the pressure derivative of solution density, partial molar volumes, and composition derivatives of activity coefficients. For dense fluids, the integrals follow a...... relatively simple corresponding-states behavior even for complex systems, show welldefined relationships for infinite dilution properties in complex and near-critical systems, allow estimation of mixed-solvent solubilities of gases and pharmaceuticals, and can be expressed by simple perturbation models for...

  6. Atomistic simulation on the structure and thermodynamic properties of the UCu5Al7 derivatives

    International Nuclear Information System (INIS)

    In order to study the effect of transition element M substitution on the structural properties of UCu3M2Al7 and UCu4MAl7 (M = Cr, Mn and Fe) compounds, the structural properties are investigated using the pair potentials based on the lattice inversion technique. The calculated lattice constants are found to be in good agreement with the experimental values. The properties related to lattice vibration, such as the phonon density of states, specific heat and vibrational entropy, are also evaluated. This is an attempt to predict the structural and thermodynamic properties for actinide materials with a complex structure

  7. A note on electrical and thermodynamic properties of Isolated Horizon

    OpenAIRE

    Chen, Gerui; Wu, Xiaoning; Gao, Sijie

    2014-01-01

    The electrical laws and Carnot cycle of Isolated Horizon (IH) are investigated in this paper. We establish the Ohm's law and Joule's law of an Isolated Horizon, and find that the conceptual picture of black holes (Membrane Paradigm) can also apply to this kind of quasi-local black holes. We also investigate the geometrical properties near a non-rotating IH, and find that under the first-order approximation of r, there exist a Killing vector and a Hamiltonian conjugate to it, so this vector is...

  8. Thermodynamic properties of Cu–Zr melts: The role of chemical interaction

    Energy Technology Data Exchange (ETDEWEB)

    Kulikova, T.V.; Majorova, A.V.; Shunyaev, K.Yu. [Institute of Metallurgy, Ural Division of Russian Academy of Sciences, Amudsena str. 101, 620016 Ekaterinburg (Russian Federation); Ryltsev, R.E., E-mail: rrylcev@mail.ru [Institute of Metallurgy, Ural Division of Russian Academy of Sciences, Amudsena str. 101, 620016 Ekaterinburg (Russian Federation); Ural Federal University, Mira str. 19, 620002 Ekaterinburg (Russian Federation)

    2015-06-15

    General statistical model is applied to analyze the role of chemical interaction in associated systems. We show that, at certain conditions, chemical interaction between associates may be not essential above a distectic point and so the model of ideal associated solutions is a good approximation for describing high temperature properties of associated system with chemical interaction. Within the frames of such conception, we calculate thermodynamic properties of Cu–Zr system in liquid state. The enthalpies of formation of Cu–Zr intermetallic compounds were redefined by using matching procedure taking into account the additive manifestation of chemical interaction. We conclude that simple model which is free of adjusting parameters allows us to calculate thermodynamic properties of Cu–Zr melts with quite good accuracy.

  9. Thermodynamic and surface properties of Sb-Sn and In-Sn liquid alloys

    Indian Academy of Sciences (India)

    B C Anusionwu

    2006-08-01

    The thermodynamic properties of Sb-Sn and In-Sn liquid alloys have been studied using the quasi-chemical model for compound forming binary alloys and that for simple regular alloys. The concentration fluctuation cc(0) and the Warren-Cowley short-range order parameter (1) were determined for the whole concentration range at a temperature of 770 K. The surface tensions of these liquid alloys were determined for the whole concentration range by using energetics determined from thermodynamic calculations. In all calculations, In{Sn manifested properties very close to alloys of ideal mixing, while Sb-Sn showed properties that are asymmetric about equiatomic composition. Our results suggest that a weak complex of the form SbSn2 could be present in the Sb-Sn alloy at a temperature of about 770 K.

  10. Thermodynamic and transport properties of uranium dioxide and related phases

    International Nuclear Information System (INIS)

    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 U2.27 to a hypostoichiometric (UO2-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 UO2-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

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

    Science.gov (United States)

    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

  12. Impact of pairing on thermodynamical properties of stellar matter

    Science.gov (United States)

    Burrello, S.; Aymard, F.; Colonna, M.; Gulminelli, F.; Raduta, Ad. R.

    2016-05-01

    Superfluidity in the crust is a key ingredient for the cooling properties of proto-neutron stars. Investigations on crust superfluidity carried out so far typically assumed that the cluster component was given by a single representative nucleus and did not consider the fact that at finite temperature a wide distribution of nuclei is expected to be populated at a given crust pressure condition. We want to assess the importance of this distribution on the calculation of the heat capacity in the inner crust, in the framework of an extended NSE model. We additionally show that it is very important to consider the temperature evolution of the proton fraction, imposed by the β-equilibrium condition, for a quantitatively reliable estimation of the heat capacity.

  13. Black Holes Classical Properties, Thermodynamics and Heuristic Quantization

    CERN Document Server

    Bekenstein, J D

    1998-01-01

    I discuss the no hair principle, the recently found hairy solutions, generic properties of nonvacuum spherical static black holes, and the new no scalar hair theorems. I go into the generic phenomenon of superradiance, first uniform linear motion superradiance, then Kerr black hole superradiance, and finally general rotational superradiance and its possible applications in the laboratory. I show that the horizon area of a nearly stationary black hole can be regarded as an adiabatic invariant. This invariance suggests that quantum horizon area is quantized in multiples of a basic unit. Consideration of the quantum version of the Christodoulou reversible processes provides support for this idea. Horizon area quantization dictates a definite discrete black hole mass spectrum, so that Hawking's semiclassical spectrum is predicted to be replaced by a spectrum of nearly uniformly spaced lines whose envelope is roughly Planckian. Line natural broadening seems not enough to wash out the lines. To check on the possibi...

  14. Thermodynamical properties of the ICM from hydrodynamical simulations

    CERN Document Server

    Borgani, S; Dolag, K; Schindler, S

    2008-01-01

    Modern hydrodynamical simulations offer nowadays a powerful means to trace the evolution of the X-ray properties of the intra-cluster medium (ICM) during the cosmological history of the hierarchical build up of galaxy clusters. In this paper we review the current status of these simulations and how their predictions fare in reproducing the most recent X-ray observations of clusters. After briefly discussing the shortcomings of the self-similar model, based on assuming that gravity only drives the evolution of the ICM, we discuss how the processes of gas cooling and non-gravitational heating are expected to bring model predictions into better agreement with observational data. We then present results from the hydrodynamical simulations, performed by different groups, and how they compare with observational data. As terms of comparison, we use X-ray scaling relations between mass, luminosity, temperature and pressure, as well as the profiles of temperature and entropy. The results of this comparison can be summ...

  15. Vibrational and thermodynamic properties of α-, β-, γ-, and 6, 6, 12-graphyne structures

    International Nuclear Information System (INIS)

    Electronic, vibrational, and thermodynamic properties of different graphyne structures, namely α-, β-, γ-, and 6,6,12-graphyne, are investigated through first principles–based quasi-harmonic approximation by using phonon dispersions predicted from density-functional perturbation theory. Similar to graphene, graphyne was shown to exhibit a structure with extraordinary electronic features, mechanical hardness, thermal resistance, and very high conductivity from different calculation methods. Hence, characterizing its phonon dispersions and vibrational and thermodynamic properties in a systematic way is of great importance for both understanding its fundamental molecular properties and also figuring out its phase stability issues at different temperatures. Thus, in this research work, thermodynamic stability of different graphyne allotropes is assessed by investigating vibrational properties, lattice thermal expansion coefficients, and Gibbs free energy. According to our results, although the imaginary vibrational frequencies exist for β-graphyne, there is no such a negative behavior for α-, γ-, and 6,6,12-graphyne structures. In general, the Grüneisen parameters and linear thermal expansion coefficients of these structures are calculated to be rather more negative when compared to those of the graphene structure. In addition, the predicted difference between the binding energies per atom for the structures of graphene and graphyne points out that graphyne networks have relatively lower phase stability in comparison with the graphene structures. (papers)

  16. Theoretical investigations on the elastic and thermodynamic properties of rhenium phosphide

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Qun; Zhu, Xuanmin; Lin, Zhengzhe; Yao, Ronghui [Xidian Univ., Xi' an (China). School of Physics and Optoelectronic Engineering; Yan, Haiyan [Baoji Univ. of Arts and Sciences (China). Dept. of Chemistry and Chemical Engineering

    2016-04-01

    Structural, mechanical, and electronic properties of orthorhombic rhenium phosphide (Re{sub 2}P) are systematically investigated by using first principles calculations. The elastic constants and anisotropy of elastic properties are obtained. The metallic character of Re{sub 2}P is demonstrated by density of state calculations. The quasi-harmonic Debye model is applied to the study of the thermodynamic properties. The thermal expansion, heat capacities, and Grueneisen parameter on the temperature and pressure have been determined as a function of temperature and pressure in the pressure range from 0 to 100 GPa and the temperature range from 0 to 1600 K.

  17. Sorption potential of rice husk for the removal of 2,4-dichlorophenol from aqueous solutions: Kinetic and thermodynamic investigations

    International Nuclear Information System (INIS)

    The sorption potential of chemically and thermally treated rice husk (RHT) for the removal of 2,4-dichlorophenol (DCP) from aqueous solutions has been investigated. Sorption of DCP by rice husk was observed over a wide pH range of 1-10. The effect of contact time between liquid and solid phases, sorbent dose, pH, concentration of sorbate and temperature on the sorption of DCP onto rice husk has been studied. The pore area and average pore diameter of RHT by BET method are calculated to be 17+/-0.6m2g-1 and 51.3+/-1.5nm, respectively. Maximum sorption (98+/-1.2%) was achieved for RHT from 6.1x10-5moldm-3 of sorbate solution using 0.1g of rice husk for 10min agitation time at pH 6 and 303K, which is comparable to activated carbon commercial (ACC) 96.6+/-1.2%, but significantly higher than chemically treated rice husk (RHCT) 65+/-1.6% and rice husk untreated (RHUT) 41+/-2.3%. The sorption data obtained at optimized conditions was subjected to Freundlich, Langmuir and Dubinin-Radushkevich (D-R) isotherms. Sorption intensity 1/n (0.31+/-0.01) and sorption capacity multilayer Cm (12.0+/-1.6mmolg-1) have been evaluated using Freundlich sorption isotherm, whereas the values of sorption capacity monolayer Q (0.96+/-0.03mmolg-1) and binding energy, b (4.5+/-1.0)x104dm3mol-1 have been estimated by Langmuir isotherm. The Langmuir constant, b, was also used to calculate the dimensionless factor, RL, in the concentration range (0.6-6.1)x10-4moldm-3, suggesting greater sorption at low concentration. D-R sorption isotherm was employed to calculate sorption capacity Xm (2.5+/-0.07mmolg-1) and sorption energy E (14.7+/-0.13kJmol-1). Lagergren and Morris-Weber equations were employed to study kinetics of sorption process using 0.2g of RHT, 25cm3 of 0.61x10-4moldm-3 sorbate concentration at pH 6, giving values of first-order rate constant, k, and rate constant of intraparticle transport, Rid (0.48+/-0.04min-1 and 6.8+/-0.8nmolg-1min-1/2, respectively) at 0.61x10-4moldm-3 solution

  18. Structural and thermodynamic properties of 3-d transition metals: Pseudopotential theory revisited

    International Nuclear Information System (INIS)

    Structural and thermodynamic properties of 3d-transition metals are calculated in terms of the pseudopotential theory. The s-p and d-electrons are treated in a pseudoadiabatic approximation in such a way so that the s-p and d-electron are treated separately under the same footing. The s-p electrons are treated in terms of the conventional second-order pseudopotential theory, while the tightly bound d-electrons are treated in terms of the Wills-Harrison prescription that makes use of the Fridel rectangular electron-density of states (DOS) model. The predictions of the structural phase stability and other relevant thermodynamic properties are found to be consistent with experiments for almost all of the metals. (author). 16 refs, 5 tabs

  19. Pressure effect on structural, elastic, and thermodynamic properties of tetragonal B4C4

    International Nuclear Information System (INIS)

    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

  20. Ab Initio Calculation of Structure and Thermodynamic Properties of Zintl Aluminide SrAl2

    Science.gov (United States)

    Fu, Zhi-Jian; Jia, Li-Jun; Xia, Ji-Hong; Tang, Ke; Li, Zhao-Hong; Sun, Xiao-Wei; Chen, Qi-Feng

    2015-12-01

    The structural and thermodynamic properties of the orthorhombic and cubic structure SrAl2 at pressure and temperature are investigated by using the ab initio plane-wave pseudopotential density functional theory methodwithin the generalised gradient approximation (GGA). The calculated lattice parameters are in agreement with the available experimental data and other theoretical results. The phase transition predicted takes place at 0.5 GPa from the orthorhombic to the cubic structure at zero temperature. The thermodynamic properties of the zinc-blende structure SrAl2 are calculated by the quasi-harmonic Debye model. The pressure-volume relationship and the variations inthe thermal expansion α are obtained systematically in the pressure and temperature ranges of 0-5 GPa and 0-500 K, respectively.

  1. 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.

  2. Structural, elastic and thermodynamic properties of the tetragonal structure of germanium carbonitride

    Science.gov (United States)

    Xing, Mengjiang; Li, Binhua; Yu, Zhengtao; Chen, Qi

    2016-04-01

    The structural, mechanical, electronic and thermodynamic properties of the tetragonal structure germanium carbonitride (t-GeCN) were first investigated using the density function theory with the ultrasoft psedopotential scheme in the frame of the generalized gradient approximation and the local density approximation. The elastic constants have confirmed that the t-GeCN is mechanically stable and phonon spectra have confirmed that the t-GeCN is dynamically stable. The anisotropy studies show that t-GeCN exhibits a larger anisotropy in its Poisson's ratio, Young's modulus, shear modulus, sound velocities and universal elastic anisotropy index. Electronic structure study shows that t-GeCN is an indirect semiconductor with band gap of 0.628 eV. The thermodynamic properties of t-GeCN, including Debye temperature, heat capacity, Grüneisen parameter and thermal expansion coefficient are investigated utilizing the quasi-harmonic Debye model.

  3. Elastic and thermodynamic properties of Fe3Ga from first-principles calculations

    Science.gov (United States)

    Lin, Ya-Ning; Li, Lin-Ling; Yan, Xiang-Hong; Zhang, Ya-Ping; Zhang, Dong-yun; Zhang, Peng

    2016-03-01

    First-principles calculations within the framework of density functional theory (DFT) are performed to investigate the elastic and thermodynamic properties of DO3-type Fe3Ga alloy. The obtained lattice constants and the bulk modulus are in good agreement with available experimental data. In terms of the calculated formation energy and Poisson's ratio, the Fe3Ga alloy is mechanically stable and exhibit a negative Poisson's ratio of -0.81 along the direction. The thermodynamic properties such as the Gibbs free energy, thermal expansion, and the specific heat are obtained by the first-principles phonon calculations with the quasiharmonic approximation method. The predicted coefficient of linear thermal expansion and specific heat may provide a helpful reference for experimental work.

  4. The thermodynamic properties of the upper continental crust: Exergy, Gibbs free energy and enthalpy

    International Nuclear Information System (INIS)

    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 × 106 Gtoe. However, this study shows that approximately only 0.01% of that amount can be effectively used by man.

  5. 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 thermodynamic s Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.200, year: 2014

  6. Optical properties of chitosan in aqueous solution of L- and D-ascorbic acids

    Science.gov (United States)

    Malinkina, Olga N.; Shipovskaya, Anna B.; Kazmicheva, Olga F.

    2016-04-01

    The optical properties of aqueous chitosan solutions in L- and D-ascorbic acids were studied by optical rotatory dispersion and spectrophotometry. The specific optical rotation [α] of all chitosan solutions tested was positive, in contrast to aqueous solutions of the ascorbic acid enantiomers, which exhibit an inverse relationship of [α] values. Significant differences in the absolute values of [α] of the chitosan solutions at polymer-acid ratios exceeding the equimolar one were found.

  7. Comparison of physicomechanical properties of films prepared from organic solutions and aqueous dispersion of Eudragit RL

    OpenAIRE

    H Afrasiabi Garekani; M. Shahabi; F Sadeghi

    2011-01-01

    Background and the purpose of the study: Mechanical properties of films prepared from aqueous dispersion and organic solutions of Eudragit RL were assessed and the effects of plasticizer type, concentration and curing were examined. Methods: Films were prepared from aqueous dispersion and solutions of Eudragit RL (isopropyl alcohol-water 9:1) containing 0, 10 or 20% (based on polymer weight) of PEG 400 or Triethyl Citrate (TEC) as plasticizer using casting method. Samples of films were stored...

  8. Effect of peritectics on thermodynamic properties of homogeneous binary metallic melts

    Institute of Scientific and Technical Information of China (English)

    张鉴

    2001-01-01

    After formulation of the calculating models of mass action concentrations for metallic melts Cu-Al, Ni-Al and Cu-Sn, it is found that in spite of their lower stability than that of compounds with congruent melting point, peritectics are popular structural units in metallic melts, neglecting their presence will make it impossible to study the thermodynamic properties of metallic melts with results which both obey the law of mass action and agree well with practice.

  9. Thermodynamics properties of tachyon cosmology with non-minimal coupling to matter

    OpenAIRE

    Farajollahi, H.; Ravanpak, A.; Abolghasemi, M.

    2016-01-01

    Recently, we have investigated the dynamics of the universe in tachyon cosmology with non-minimal coupling to matter \\cite{faraj}-\\cite{faraj3}. In particular, for the interacting holographic dark energy (IHDE), the model is studied in \\cite{Ravanpak}. In the current work, a significant observational program has been conducted to unveil the model's thermodynamic properties. Our result shows that the IHDE version of our model better fits the observational data than $\\Lambda$CDM model. The firs...

  10. Verma procedure to determine thermodynamic properties of liquids; Procedimiento Verma para determinar propiedades termodinamicas de liquidos

    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

  11. Thermodynamic properties of the noncommutative black hole in (z = 3)-Horava-Lifshitz gravity

    OpenAIRE

    NACH, Mourad; BILAL, Khadija; SEDRA, My Brahim; BOUKILI, Abderrahman EL

    2013-01-01

    In this work, we investigate the effects of noncommutative spaces on the Horava-Lifshitz black hole. We construct the black hole solutions in the noncommutative space of (z = 3)-Horava-Lifshitz gravity. We calculate the horizon and the thermodynamic properties such as the Hawking temperature, the ADM-Mass, and entropy, which reduce to their commutative limits when the noncommutativity parameter tends to zero.

  12. Mathematical modeling and determination of thermodynamic properties of jabuticaba peel during the drying process

    OpenAIRE

    Cristian F. Costa; Paulo C. Corrêa; Jaime D. B. Vanegas; Fernanda M. Baptestini; Renata C. Campos; Lara S. Fernandes

    2016-01-01

    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 circulatio...

  13. Densities and Derived Thermodynamic Properties of Imidazolium-, Pyridinium-, Pyrrolidinium-, and Piperidinium-Based Ionic Liquids

    OpenAIRE

    Gardas, Ramesh L.; Costa, Henrique F.; Freire, Mara G.; Carvalho, Pedro J.; Marrucho, Isabel M.; Fonseca, Isabel M. A.; Ferreira, Abel G. M.; Coutinho, João A. P.

    2008-01-01

    In the present work, experimental density measurements are reported along with the derived thermodynamic properties, such as the isothermal compressibility (κT), the isobaric expansivity (αp), and the thermal pressure coefficient (γv) for imidazolium-, pyridinium-, pyrrolidinium-, and piperidinium-based ionic liquids (ILs), namely, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate [C2mim][CF3SO3], 3-methyl-1-propylpyridinium bis(trifluoromethylsulfonyl)imide [C3mpy][NTf2], 1-methyl-1-prop...

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

    Czech Academy of Sciences Publication Activity Database

    Hrubý, Jan; Duška, Michal

    Liberec: Technical University of Liberec, 2013 - (Vít, T.; Dančová, P.; Novotný, P.), s. 279-284 ISBN 978-80-260-5375-0. [Experimental Fluid Mechanics 2013. Kutná hora (CZ), 19.11.2013-22.11.2013] R&D Projects: GA ČR(CZ) GAP101/11/1593 Institutional support: RVO:61388998 Keywords : steam * condensation * thermodynamic properties * computational fluid dynamics Subject RIV: JE - Non-nuclear Energetics, Energy Consumption ; Use

  15. PREDICTION ON THE THERMODYNAMIC PROPERTIES OF TERNARY LIQUID ALLOYS BY MODIFIED COORDINATION EQUATION

    Institute of Scientific and Technical Information of China (English)

    D.P.Tao

    2001-01-01

    The coordination numbers in the Molecular Interaction Volume Model can be calcu-lated from the common physical quantities of pure matters.A significant advantage ofthe model lies in its ability to predict the thermodynamic properties of ternary liqmdalloys using only the binary infinite dilute activity coefficients,and the predicted values are in good agreement with the experimental data of ternary liquid alloys,whichshows that the model is reliable,convenient and economic.

  16. Obtaining and thermodynamic properties of cobalt fluoride tetrahydrate and cobalt hydroxycarbonate

    International Nuclear Information System (INIS)

    Present article is devoted to obtaining and thermodynamic properties of cobalt fluoride tetrahydrate and cobalt hydroxycarbonate. Therefore, the cobalt fluoride tetrahydrate (II) was obtained by the reaction of cobalt hydroxycarbonate(II) with hydrofluoric acid solutions of different concentrations. The enthalpy and adverse reactions was defined by means of calorimetry method. The enthalpy of formation of cobalt fluoride tetrahydrate (II) and cobalt hydroxycarbonate(II) was determined by thermochemical cycles.

  17. Thermodynamic properties of the liquid Ag-Bi-Cu-Sn lead-free solder alloys

    OpenAIRE

    Garzel G.; Kopyto M.; Zabdyr L.A.

    2014-01-01

    The electromotive force measurement method was employed to determine the thermodynamic properties of liquid Ag-Bi-Cu-Sn alloys using solid electrolyte galvanic cells as shown below: Kanthal+Re, Ag-Bi-Cu-Sn, SnO2 | Yttria Stabilized Zirconia | air, Pt, Experiments were made within temperature interval: 950 - 1300K along four composition paths of constant ratios: XAg : XBi : XCu = 1, XAg : (XBi + XCu) = 3:2 for XBi = XCu, XBi : (XAg + XCu) = 3:2 for XAg = XCu...

  18. Investigation into thermodynamic properties of indium-copper system alloys by method of instant emf registration

    International Nuclear Information System (INIS)

    Direct measurement of activity of In-Cu alloy both components is carried out. Thermodynamic properties of (In0.147Cu0.853; In0.326Cu0.674; In0.341Cu0.659; In0.302Cu0.638; In0.617Cu0.383) alloys calculated proceeding from the measured activities, well agree with each other and the literary data. 6 refs.; 3 tabs

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

    Science.gov (United States)

    Hemingway, B.S.

    1987-01-01

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

  20. Removal of Basic Dyes from Aqueous Solution by Chloroacetic Acid Modified Ferula Communis Based Adsorbent: Thermodynamic and Kinetic Studies

    OpenAIRE

    Salih, Shameran Jamal

    2014-01-01

    ABSTRACT: This research aimed to propose an alternative cheap and abundantly available adsorbent (Ferula communis) for the removal of basic dyes from aqueous solutions. Chloroacetic acid modified Ferula communis (MFC) shows a great potential for the removal of basic red 9 dyes (BR9) from aqueous solution with the effects of solution capacity under pH, temperature, contact time, adsorbent dosage, and initial dye concentration condition on BR9 removal were examined. The adsorption equilibrium d...

  1. Thermodynamic Properties of Selected Homologous Series of Ionic Liquids Calculated Using Molecular Dynamics.

    Science.gov (United States)

    Červinka, Ctirad; Pádua, Agilio A H; Fulem, Michal

    2016-03-10

    This work presents a molecular dynamics simulation study concerning the thermodynamic data of ionic liquids (ILs) including phase change enthalpies, liquid phase densities, radial and spatial distribution functions, and diffusive properties. Three homologous series of ILs were selected for this study, namely, 1-alkyl-3-methylimidazolium tetrafluoroborates, hexafluorophosphates, and 1,1,2,2-tetrafluoroethanesulfonates, so that properties of 36 ILs are calculated in total. The trends of calculated properties are compared to available experimental data and thoroughly discussed in context of the homologous series. The calculated trends of the vaporization enthalpies within the series are supported by analyzing the structural properties of the ILs. An excellent agreement of calculated structural properties (liquid phase density) with the experimental counterparts is reached. The calculated enthalpic properties are overestimated considerably; thus, further development of the force fields for ILs is required. PMID:26848831

  2. An EQT-cDFT approach to determine thermodynamic properties of confined fluids

    International Nuclear Information System (INIS)

    We present a continuum-based approach to predict the structure and thermodynamic properties of confined fluids at multiple length-scales, ranging from a few angstroms to macro-meters. The continuum approach is based on the empirical potential-based quasi-continuum theory (EQT) and classical density functional theory (cDFT). EQT is a simple and fast approach to predict inhomogeneous density and potential profiles of confined fluids. We use EQT potentials to construct a grand potential functional for cDFT. The EQT-cDFT-based grand potential can be used to predict various thermodynamic properties of confined fluids. In this work, we demonstrate the EQT-cDFT approach by simulating Lennard-Jones fluids, namely, methane and argon, confined inside slit-like channels of graphene. We show that the EQT-cDFT can accurately predict the structure and thermodynamic properties, such as density profiles, adsorption, local pressure tensor, surface tension, and solvation force, of confined fluids as compared to the molecular dynamics simulation results

  3. Thermodynamic data for the speciation and solubility of Pd, Pb, Sn, Sb, Nb and Bi in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Lothenbach, B.; Ochs, M. [BMG Engineering Ltd., Zuerich-Schlieren (Switzerland); Wanner, H.; Yui, Mikazu

    1999-01-01

    This report provides thermodynamic data for predicting concentrations of palladium, lead, tin, antimony, niobium and bismuth in geologic environments, and contributes to an integration of the JNC chemical thermodynamic database, JNC-TDB (previously PNC-TDB), for the performance analysis of geological isolation system of high-level radioactive wastes. Besides treating hydrolysis in detail, this report focuses on the formation of complexes or compounds with chloride, fluoride, carbonate, nitrate, sulfate and phosphate. Other important inorganic ligands (sulfide for lead and antimony, ammonia for palladium) are also included. In this study, the specific ion interaction theory (SIT) approach is used to extrapolate thermodynamic constants to zero ionic strength at 25degC. (author)

  4. Thermodynamic properties of 1-naphthol: Mutual validation of experimental and computational results

    International Nuclear Information System (INIS)

    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

  5. Adsorption and correlation with their thermodynamic properties of triazine herbicides on soils

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Adsorption of atrazine, prometryne and prometon was determined on six soils with different physical and chemical properties. Theadsorption isotherms of three herbicides could well fit Freundlich equation. On all of six soils, adsorption of herbicides increased in the order:atrazine ≈ prometon < prometryne. This order is quite the same to the calculation result of by means of excess thermodynamic properties oftriazine. The Freundlich adsorption constants, Kf, showed to have good correlation with organic matter(OM%) of soils for each of theseherbicides, suggesting that OM is the main factor, which dominates in the adsorption process of these triazine herbicides.

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

    Science.gov (United States)

    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.

  7. Thermodynamic characteristics of the acid-base equilibria of taurine in aqueous solutions, according to calorimetry data

    Science.gov (United States)

    Gridchin, S. N.; Shekhanov, R. F.; Pyreu, D. F.

    2015-02-01

    Enthalpies of the neutralization and protonation of taurine (HL) are measured by direct calorimetry at 298.15 K and ionic strengths of 0.3, 0.5, and 1.0 (KNO3). The standard thermodynamic characteristics of HL protolytic equilibria are calculated.

  8. Thermodynamic modeling of CO2 absorption in aqueous N-Methyldiethanolamine using Extended UNIQUAC model

    DEFF Research Database (Denmark)

    Sadegh, Negar; Stenby, Erling Halfdan; Thomsen, Kaj

    2015-01-01

    A Thermodynamic model that can predict the behavior of the gas sweetening process over the applicable conditions is of vital importance in industry. In this work, Extended UNIQUAC model parameters optimized for the CO2-MDEA-H2O system are presented. Different types of experimental data consisting...

  9. Electrodynamic balance measurements of thermodynamic, kinetic, and optical aerosol properties inaccessible to bulk methods

    Directory of Open Access Journals (Sweden)

    S. S. Steimer

    2015-06-01

    Full Text Available Measurements of a single, levitated particle in an electrodynamic balance are an established tool for deriving thermodynamic and material data such as density, refractive index and activities of components of an aqueous solution under supersaturated conditions, where bulk measurements are not possible. The retrieval relies on combining mass-to-charge data and size data from light scattering. Here, we use a combination of low- and high-resolution Mie resonance spectroscopy to obtain radius data, enabling an accurate size determination not only when the particle is in equilibrium, but also when it is out of equilibrium due to kinetic limitation of mass transport. With the data measured under non-equilibrium conditions, it is possible to retrieve the water diffusivity. A challenge is that the radius retrieval by comparing measured light scattering with Mie theory requires the knowledge of refractive index as a function of concentration. Here, we show an iterative retrieval of refractive index and size for compounds for which data cannot be obtained in the bulk either due to lack of sufficient amounts of sample or limited solubility. We demonstrate the measurement strategy and the retrieval of water activity, density, refractive index and water diffusivity for aqueous shikimic acid. Water diffusivity in concentrated shikimic acid decreases by 6 orders of magnitude at 250 K compared to that at room temperature.

  10. Electrodynamic balance measurements of thermodynamic, kinetic, and optical aerosol properties inaccessible to bulk methods

    Directory of Open Access Journals (Sweden)

    S. S. Steimer

    2015-01-01

    Full Text Available Measurements of a single, levitated particle in an electrodynamic balance are an established tool for deriving thermodynamic and material data such as density, refractive index and activities of components of an aqueous solution under supersaturated conditions, where bulk measurements are not possible. The retrieval relies on combining mass-to-charge data and size data from light scattering. Here, we use a combination of low- and high-resolution Mie resonance spectroscopy to obtain radius data, enabling an accurate size determination not only when the particle is in equilibrium, but also when it is out of equilibrium due to kinetic limitation of mass transport. With the data measured under non-equilibrium conditions, it is possible to retrieve the water diffusivity. A challenge is that the radius retrieval by comparing measured light scattering with Mie theory requires the knowledge of refractive index as a function of concentration. Here, we show an iterative retrieval of refractive index and size for compounds for which data cannot be obtained in the bulk either due to lack of sufficient amounts of sample or limited solubility. We demonstrate the measurement strategy and the retrieval of water activity, density, refractive index and water diffusivity for aqueous shikimic acid. Water diffusivity in concentrated shikimic acid decreases by 6 orders of magnitude at 250 K compared to that at room temperature.

  11. Influence of coal properties on mercury uptake from aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Lakatos, J.; Brown, S.D.; Snape, C.E. [Miskolc University, Miskolc-Egyetemvaros (Hungary). Research Inst. of Applied Chemistry

    1999-10-01

    The uptake of mercury (II) from aqueous solution by a range of coals has been studied and the results have been compared to those for a number of other sorbents, including commercial active carbons and cation-exchange resins. At pH 5 in a buffer medium, the capacities for mercury removal of the low-rank coals and the oxidized bituminous coals investigated are comparable to those of the other sorbents tested. For the lignites investigated, a high content of organic sulfur does not markedly affect the capacity for mercury uptake in relatively neutral and low chloride media, owing to redox reactions being the most likely mechanism involved. However, in highly acidic solutions, the capacities for mercury uptake are considerably greater for the high-sulfur coals investigated than for their low-sulfur counterparts due to chelation being the major sorption process involved. 36 refs., 4 figs., 7 tabs.

  12. Electrochemical Properties of Nanoporous Carbon Material in Aqueous Electrolytes.

    Science.gov (United States)

    Rachiy, Bogdan I; Budzulyak, Ivan M; Vashchynsky, Vitalii M; Ivanichok, Nataliia Ya; Nykoliuk, Marian O

    2016-12-01

    The paper is devoted to the study of the behavior of capacitor type electrochemical system in the К(+)-containing aqueous electrolytes. Nanoporous carbon material (NCM) was used as the electrode material, obtained by carbonization of plant raw materials with the following chemical activation. Optimization of pore size distribution was carried out by chemical-thermal method using potassium hydroxide as activator. It is shown that obtained materials have high values of capacitance which is realized by charge storage on the electrical double layer and by pseudocapacitive ion storage on the surface of the material. It is established that based on NCM, electrochemical capacitors are stable in all range of current density and material capacity essentially depends on appropriate choice of electrolyte. PMID:26759354

  13. First principles study of thermodynamic and mechanical properties of Pd50Cu50

    International Nuclear Information System (INIS)

    Highlights: • Four structures of Pd50Cu50 are thermodynamically and mechanical stable. • Each structure of Pd50Cu50 has a descending sequence of C11 → C12 → C44. • Heat capacities of four structures of Pd50Cu50 are very close to each other. • B2 is more appropriate for hydrogen permeation than other structures. • Calculated results are in good agreement with experimental observations. - Abstract: First principles calculation, quasi-harmonic approximation, and thermal electronic excitation are combined to investigate temperature-dependent thermodynamic and mechanical properties of Pd50Cu50. It is found that the ordered (B2, L10) as well as BCC and FCC solid solutions of Pd50Cu50 are not only energetically favorable with negative heats of formation, but also mechanical stable. Calculations also reveal that heat capacities of the four structures of Pd50Cu50 at a certain temperature are very close to each other, and that the elastic constants of each structure have a descending sequence of C11 → C12 → C44 within the entire temperature range. Moreover, the B2 structure has the smallest coefficient of thermal expansion as well as brittleness among the four structures, suggesting that the B2 structure of Pd50Cu50 should be more appropriate for hydrogen permeation in terms of thermodynamic and mechanical properties. The calculated results are in good agreement with experimental observations in the literature

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

    Institute of Scientific and Technical Information of China (English)

    韦昭; 翟东; 邵晓红; 鲁勇; 张平

    2015-01-01

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

  15. Thermodynamic study of copper sulphate and zinc sulphate in water and binary aqueous mixtures of propylene glycol

    Directory of Open Access Journals (Sweden)

    R. C. Thakur

    2015-03-01

    Full Text Available Partial molar volumes of copper sulphate and zinc sulphate have been determined in water and binary aqueous mixtures of propylene glycol (2,4,6 and 8% by weight of propylene glycol at 303.15 K with the help of density measurements. Effect of temperature on the partial molar volumes was also analysed for these salts in water and binary aqueous mixtures of propylene glycol. Results obtained have been analysed by Masson’s equation and the experimental values of slopes and partial molar volumes of these transition metals sulphates have been interpreted in terms of ion-ion or ion –solvent interactions. Limiting molar expansibilities ( have also been determined which is interpreted in terms of structure making or breaking capacities of transition metal sulphates. The transition metal sulphates have been found as structure promoter in water and binary aqueous mixture of propylene glycol.

  16. First-principles study of Vickers hardness and thermodynamic properties of Ti3SnC2 polymorphs

    OpenAIRE

    Rayhan, M. A.; Ali, M. A.; Naqib, S. H.; Islam, A. K. M. A.

    2015-01-01

    We have investigated Vickers hardness and the thermodynamic properties of the recently discovered nanolaminate carbide Ti3SnC2 polymorphs using the first-principles calculations. The chemical bonding shows a combination of covalent, ionic and metallic types. The strong covalent bonding is mainly responsible for high Vickers hardness of Ti3SnC2 polymorphs. Thermodynamic properties are studied using the quasi-harmonic Debye model. The variation of bulk modulus, thermal expansion co-efficient, s...

  17. Theoretical Studies on the Structures,Stabilities,Vibrational Spectra,and Thermodynamic Properties of Polyn itromethylbenzenes

    Institute of Scientific and Technical Information of China (English)

    WANG Guixiang; GONG Xuedong; LIU Yan; XIAO Heming

    2009-01-01

    The nitro derivatives of methylbenzenes were optimized to obtain their molecular geometries and electronic structures at the DFT-B3LYP/6-31G* level.The structure parameters,such as the C-NO2 bond length(LC-NO2)and the least C-NO2 bond overlap population(MC-NO2)were focused to predict their relative stability or sensitivity.Their IR spectra were obtained and assigned by vibrational analysis,which are reliable compared with the experimental results.Based on the frequencies scaled by 0.96 and the principle of statistic thermodynamics,the thermodynamic properties were evaluated,which are linearly related with the number of nitro and methyl groups as well as the temperature,obviously showing good group additivity.

  18. Thermodynamics properties of tachyon cosmology with non-minimal coupling to matter

    CERN Document Server

    Farajollahi, H; Abolghasemi, M

    2016-01-01

    Recently, we have investigated the dynamics of the universe in tachyon cosmology with non-minimal coupling to matter \\cite{faraj}-\\cite{faraj3}. In particular, for the interacting holographic dark energy (IHDE), the model is studied in \\cite{Ravanpak}. In the current work, a significant observational program has been conducted to unveil the model's thermodynamic properties. Our result shows that the IHDE version of our model better fits the observational data than $\\Lambda$CDM model. The first and generalized second thermodynamics laws for the universe enveloped by cosmological apparent and event horizon are revisited. From the results, both first and generalized second laws, constrained by the observational data, are satisfied on cosmological apparent horizon.In addition, the total entropy is verified with the observation only if the horizon of the universe is taken as apparent horizon. Then, due to validity of generalized second law, the current cosmic acceleration is also predicted.

  19. Critical evaluation and optimization of the thermodynamic properties of liquid tin solutions

    Science.gov (United States)

    Heuzey, Marie-Claude; Pelton, Arthur D.

    1996-10-01

    Thermodynamic and phase equilibrium data for the following 18 elements in molten Sn were collected and critically evaluated: Al, Ca, Ce, Co, Cr, Cu, Fe, H, Mg, Mo, Na, Ni, O, P, S, Se, Si, and Ti. Binary and ternary data were optimized to give polynomial expressions for the excess Gibbs energies as functions of temperature and composition. For some solutes, the optimized expressions are valid over the entire composition range 0 ≤ XSn ≤ 1. In other cases, the expressions apply to Snrich solutions. Solute-solute interaction terms were estimated where data were not available. The optimized Gibbs energy expressions are also presented in the form of interaction parameters, and the equivalence between the polynomial and interaction parameter formalisms is discussed. Through the Kohler equation, or the modified interaction parameter formalism, the thermodynamic properties of the multicomponent solution of 18 elements in Sn can be calculated. The database is suitable for computer storage and manipulation.

  20. Thermodynamic properties of Mg2Si and Mg2Ge investigated by first principles method

    International Nuclear Information System (INIS)

    The lattice dynamics and thermodynamic properties of Mg2Si and Mg2Ge 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.

  1. A re-assessment of the thermodynamic properties of iodine condensed phases

    International Nuclear Information System (INIS)

    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.

  2. Solvent effect on molecular structure, IR spectra, thermodynamic properties and chemical stability of zoledronic acid: DFT study.

    Science.gov (United States)

    Liu, Qingzhu; Qiu, Ling; Wang, Yang; Lv, Gaochao; Liu, Guiqing; Wang, Shanshan; Lin, Jianguo

    2016-04-01

    Zoledronic acid (ZL) has been used widely for treating skeletal diseases because of its high potency in inhibiting bone resorption. A detailed understanding of its physicochemical characteristics may be of great significance in both medicinal chemistry and structural biology for the design of novel bisphosphonates with higher activity. In the present work, the monoclinic (IM) and triclinic (IT) polymorphs of ZL in the gas phase and the aqueous phase were studied by density functional theory (DFT) method at the B3LYP/6-311++G** level. The polarizable continuum model (PCM) was employed to study the solvent effect on structures and properties. The optimized IM and IT conformations in both phases are in reasonable agreement with the experimental structures with the overall mean absolute percent deviation (MAPD%) less than 3.1 %. The presence of intramolecular hydrogen bond within both conformations was identified in the solvent. The IR spectra were simulated and assigned in detail, which agreed well with the experimental data. The intramolecular hydrogen bonding interactions resulted in the shift of vibrational frequencies of hydroxyl to the low band by 12-22 cm(-1) and 24-26 cm(-1) for IM and IT conformations, respectively. Their thermodynamic properties were also calculated based on the harmonic vibrational analysis, including standard heat capacity (C(°)p,m), entropy (S(°)m), and enthalpy (H(°)m). The molecular stability, hydrogen bonding interaction and other electronic properties have been further analyzed by the natural bond orbital (NBO), atoms in molecules (AIM), molecular electrostatic potential (MEP) and frontier molecular orbital (FMO) analysis. PMID:26994018

  3. Theoretical investigation of the mechanical and thermodynamics properties of Nb3Ga superconductor under pressure

    International Nuclear Information System (INIS)

    The mechanical and thermodynamics properties of Nb3Ga under pressure have been studied and analyzed using first-principles combined with quasi-harmonic Debye model. The calculated lattice parameter of the ground state is in well agreement with the experimental data. The pressure dependence of a/a0 and V/V0 are investigated, the bulk modulus B0 and its pressure derivative B′ are found to be 164.5 GPa and 3.936, respectively. The elastic constants under pressure are obtained and the polycrystalline elastic moduli of Nb3Ga are calculated derived from the single-crystal elastic constants. The results show that Nb3Ga is stable and behaves in a ductile manner up to 40 GPa. In addition, the elastic anisotropy, Vickers hardness as well as the melting temperature of Nb3Ga are investigated. Finally, the pressure and temperature dependence of the thermodynamic properties are also been obtained in the ranges of 0–40 GPa and 0–1000 K through the quasi-harmonic Debye model. - Highlights: • The physical properties of Nb3Ga were investigated. • The bulk modulus B0 and its pressure derivative B′ are found to be 164.5 GPa and 3.936. • The Nb3Ga is stable and behaves in a ductile manner up to 40 GPa. • The temperature dependence of the thermodynamic properties is obtained. • The 3D figures of the Young's modulus for Nb3Ga are obtained under pressure

  4. Structural, mechanical and thermodynamic properties of N-dope BBi compound under pressure

    Science.gov (United States)

    Yalcin, Battal G.

    2016-04-01

    The structural, mechanical and thermodynamic properties of N-dope BBi compound have been reported in the current study. The structural and mechanical results of the studied binary compounds (BN and BBi) and their ternary alloys BBi1- x N x structures are presented by means of density functional theory. The exchange and correlation effects are taken into account by using the generalized gradient approximation functional of Wu and Cohen which is an improved form of the most popular Perdew-Burke-Ernzerhof. The quasi-harmonic Debye model is used for the thermodynamic properties of studied materials. The basic physical properties of considered structures such as the equilibrium lattice parameter (a 0), bulk modulus (B 0), its pressure derivative (B'), elastic constants (C 11, C 12 and C 44), Kleinman's internal-strain parameter (ƺ), shear modulus anisotropy (A), the average shear modulus (G), Young's modulus (Y) and Poisson's ratio (v), B 0/ G ratio, microhardness parameter (H), Cauchy pressure (C″), and 1st and 2nd Lame constants (λ, μ), debye temperature (θ D), wave velocities (ν l, ν t and ν m), melting temperature (T m) and minimum thermal conductivity (κ min) have been calculated at zero pressure. In order to obtain more information, thermodynamic properties, such as internal energy (U), Helmoltz free energy (F), entropy (S), Debye temperature (θ D), thermal expansion (α), constant volume and pressure heat capacities (C V and C P ), are analyzed under the whole range from 0 to 20 GPa and temperature range from 0 to 1500 K. The obtained results of the studied binary compounds are in coincidence with experimental works.

  5. Comparisons of kinetics, thermodynamics and regeneration of tetramethylammonium hydroxide adsorption in aqueous solution with graphene oxide, zeolite and activated carbon

    Science.gov (United States)

    Chang, Shenteng; Lu, Chungsying; Lin, Kun-Yi Andrew

    2015-01-01

    Graphene oxide (GO), sodium Y-type zeolite (NaY) and granular activated carbon (GAC) are selected as adsorbents to study their kinetics, thermodynamics and regeneration of tetramethylammonium hydroxide (TMAH) adsorption from water. The adsorption kinetics follows the pseudo-second-order rate law while the adsorption thermodynamics shows an exothermic reaction with GO and GAC but displays an endothermic reaction with NaY. The adsorbed TMAH can be readily desorbed from the surface of GO and NaY by 0.05 M NaCl solution. A comparative study on the cyclic TMAH adsorption with GO, NaY and GAC is also conducted and the results reveal that GO exhibits the greatest TMAH adsorption capacity as well as superior reversibility of TMAH adsorption over 10 cycles of adsorption and desorption process. These features indicate that GO is a promising and efficient adsorbent for TMAH removal in wastewater treatment.

  6. Monte Carlo simulations of magnetic and thermodynamic properties for different nanostructure geometries

    International Nuclear Information System (INIS)

    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

  7. Mechanical properties of nanostructured, low temperature bainitic steel designed using a thermodynamic model

    International Nuclear Information System (INIS)

    Nanostructured, low temperature bainitic steels with remarkable combination of ultimate tensile strength of about 2.5 GPa and high uniform elongation have been developed in the recent decade. To reduce the production cost of these steels, two chemical compositions were designed by using a thermodynamic model which was developed in Cambridge University by Bhadeshia. To attain optimum mechanical properties, the designed steels were transformed isothermally at the temperature range of 200-300 deg. C for different times. The optimum times for each temperature were estimated by evaluation of hardness and XRD results. The measurements of tensile properties and the fracture surface examination by scanning electron microscopy indicated that by modification of chemical composition the cost production of steel not only reduces, but also the mechanical properties particularly total elongation enhances slightly. The results of this study suggest that by using a thermodynamic model and without try and error it is possible to design a new steel with remarkable combination of mechanical properties.

  8. Hydrogen bond networks determine emergent mechanical and thermodynamic properties across a protein family

    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

  9. Equilibrium, thermodynamic and kinetic studies for the biosorption of aqueous lead(II), cadmium(II) and nickel(II) ions on Spirulina platensis

    Energy Technology Data Exchange (ETDEWEB)

    Seker, Ayseguel [Department of Chemistry, Izmir Institute of Technology, Urla 35430, Izmir (Turkey)], E-mail: aysegulseker@iyte.edu.tr; Shahwan, Talal [Department of Chemistry, Izmir Institute of Technology, Urla 35430, Izmir (Turkey)], E-mail: talalshahwan@iyte.edu.tr; Eroglu, Ahmet E. [Department of Chemistry, Izmir Institute of Technology, Urla 35430, Izmir (Turkey)], E-mail: ahmeteroglu@iyte.edu.tr; Yilmaz, Sinan [Department of Chemistry, Izmir Institute of Technology, Urla 35430, Izmir (Turkey)], E-mail: sinanyilmaz@iyte.edu.tr; Demirel, Zeliha [Department of Biology, Ege University, Bornova 35100, Izmir (Turkey)], E-mail: zelihademirel@gmail.com; Dalay, Meltem Conk [Department of Bioengineering, Ege University, Bornova 35100, Izmir (Turkey)], E-mail: meltemconkdalay@gmail.com

    2008-06-15

    The biosorption of lead(II), cadmium(II) and nickel(II) ions from aqueous solution by Spirulina platensis was studied as a function of time, concentration, temperature, repetitive reactivity, and ionic competition. The kinetic results obeyed well the pseudo second-order model. Freundlich, Dubinin Radushkevich and Temkin isotherm models were applied in describing the equilibrium partition of the ions. Freundlich isotherm was applied to describe the design of a single-stage batch sorption system. According to the thermodynamic parameters such as {delta}G{sup o}, {delta}H{sup o}and {delta}S{sup o} calculated, the sorption process was endothermic and largely driven towards the products. Sorption activities in a three metal ion system were studied which indicated that there is a relative selectivity of the biosorbent towards Pb{sup 2+} ions. The measurements of the repetitive reusability of S. platensis indicated a large capacity towards the three metal ions.

  10. Thermodynamic characteristics of molecular interactions between L-tryptophan and nicotinic acid and uracyl in aqueous buffer solutions at 298 K

    Science.gov (United States)

    Badelin, V. G.; Tyunina, E. Yu.; Mezhevoi, I. N.; Tarasova, G. N.

    2015-12-01

    The interaction between L-tryptophan (Trp) and nicotinic acid (NA) and uracyl (Ur) in aqueous buffer solutions (pH 7.35) at different ratios of reagents is studied via the calorimetry of dissolution. The enthalpies of dissolution of the amino acid in the buffer solutions of the ligands at 298.15 K are obtained. The stoichiometric compositions of the complexes being formed and binding constants have been determined. The values of the thermodynamic characteristics for the complex formation of L-tryptophan with nicotinic acid and uracyl are calculated. It is shown that the formation of molecular complexes with 1 : 2 composition is stabilized by the entropy factor for the Trp-NA system, and by the enthalpy factor for the Trp-Ur system.

  11. Electron solvation in aqueous reverse micelles: Equilibrium properties

    Science.gov (United States)

    Laria, Daniel; Kapral, Raymond

    2002-10-01

    Microscopic aspects of electron solvation in aqueous reverse micelles are investigated using molecular dynamics simulation techniques. Two micelle sizes, with water/surfactant ratios of 3 and 7.5, are examined. The electron is treated quantum mechanically using Feynman path integral methods while the water, surfactant head groups, and counter ions are treated classically. Through computations of the free energy as a function of the radial distance, the electron is found to be preferentially solvated in the interior of the micelle in the "bulk" water pool. For small micelles, the presence of the electron leads to a depletion of water in the central region of the micelle and thus strongly disrupts the water equilibrium structure. Contact and solvent-separated ion pairs between the electron and Na+ counter ions are found to play an important role in the equilibrium structure. For the two micelle sizes investigated, the most stable solvation structures correspond to contact ion pairs. The localization of the electronic charge distribution is found to increase with micelle size, signaling more efficient solvation in larger micelles.

  12. Modeling of Dielectric Properties of Aqueous Salt Solutions with an Equation of State

    DEFF Research Database (Denmark)

    Maribo-Mogensen, Bjørn; Kontogeorgis, Georgios; Thomsen, Kaj

    2013-01-01

    , been ignored in relation to thermodynamic modeling, and authors have either neglected the effect of salts on permittivity or used empirical correlations fitted to the measured static permittivity, leading to an overestimation of the reduction in the thermodynamic static permittivity. We present a new...... in the electrical field surrounding ions. Kinetic depolarization may explain 25–75% of the observed decrease in the permittivity of solutions containing salts, but since this is a dynamic property, this effect should not be included in the thermodynamic modeling of electrolytes. Kinetic depolarization has, however...... methodology for obtaining the static permittivity over wide ranges of temperatures, pressures, and compositions for use within an equation of state for mixed solvents containing salts. The static permittivity is calculated from a new extension of the framework developed by Onsager, Kirkwood, and Fröhlich...

  13. Thermal properties of carbon black aqueous nanofluids for solar absorption

    Directory of Open Access Journals (Sweden)

    Han Dongxiao

    2011-01-01

    Full Text Available Abstract In this article, carbon black nanofluids were prepared by dispersing the pretreated carbon black powder into distilled water. The size and morphology of the nanoparticles were explored. The photothermal properties, optical properties, rheological behaviors, and thermal conductivities of the nanofluids were also investigated. The results showed that the nanofluids of high-volume fraction had better photothermal properties. Both carbon black powder and nanofluids had good absorption in the whole wavelength ranging from 200 to 2,500 nm. The nanofluids exhibited a shear thinning behavior. The shear viscosity increased with the increasing volume fraction and decreased with the increasing temperature at the same shear rate. The thermal conductivity of carbon black nanofluids increased with the increase of volume fraction and temperature. Carbon black nanofluids had good absorption ability of solar energy and can effectively enhance the solar absorption efficiency.

  14. Calculation of the Standard Molal Thermodynamic Properties of Crystalline, Liquid, and Gas Organic Molecules at High Temperatures and Pressures

    Science.gov (United States)

    Helgeson, Harold C.; Owens, Christine E.; Knox, Annette M.; Richard, Laurent

    1998-03-01

    Calculation of the thermodynamic properties of organic solids, liquids, and gases at high temperatures and pressures is a requisite for characterizing hydrothermal metastable equilibrium states involving these species and quantifying the chemical affinities of irreversible reactions of organic molecules in natural gas, crude oil, kerogen, and coal with minerals and organic, inorganic, and biomolecular aqueous species in interstitial waters in sedimentary basins. To facilitate calculations of this kind, coefficients for the Parameters From Group Contributions (PFGC) equation of state have been compiled for a variety of groups in organic liquids and gases. In addition, molecular weights, critical temperatures and pressures, densities at 25°C and 1 bar, transition, melting, and boiling temperatures ( Tt,Pr, Tm,Pr, and Tv,Pr, respectively) and standard molal enthalpies of transition (Δ H° t,Pr), melting (Δ H° m,Pr), and vaporization (Δ H° v,Pr) of organic species at 1 bar ( Pr) have been tabulated, together with an internally consistent and comprehensive set of standard molal Gibbs free energies and enthalpies of formation from the elements in their stable state at 298.15 K ( Tr) and Pr (Δ G° f and Δ H° f, respectively). The critical compilation also includes standard molal entropies ( S°) and volumes ( V°) at Tr and Pr, and standard molal heat capacity power function coefficients to compute the standard molal thermodynamic properties of organic solids, liquids, and gases as a function of temperature at 1 bar. These properties and coefficients have been tabulated for more than 500 crystalline solids, liquids, and gases, and those for many more can be computed from the equations of state group additivity algorithms. The crystalline species correspond to normal alkanes (C nH 2( n+1) ) with carbon numbers ( n, which is equal to the number of moles of carbon atoms in one mole of the species) ranging from 5 to 100, and 23 amino acids including glycine (C 2H 5NO

  15. Study of Thermodynamic Properties of Nonstoichiometric Phase with Compound Energy Model

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Using compound energy model (CEM), the thermodynamic properties of and were evaluated.The evaluation was based on the optimization of ZrO2-CeO2 and ZrO2-CeO1.5 systems, as well as the miscibility gap inCeO1.5-CeO2 system. Except the cubic fluorite structure phase assessed with compound energy model, all the other solutionphases were assessed with subsitutional solution model. The model parameters were evaluated through fitting the selectedexperimental data by means of thermodynamic optimization. A set of parameters with thermodynamics self-consistency wasobtained and satisfactorily described the complex relation between y in and the partial pressure of oxygen atdifferent temperatures, also the interdependence among miscellaneous factors such as temperature, oxygen partial pressure,seem to be reasonable when put into the explanation of pressureless sintering of CeO2-stabilized ZrO2 powder compacts at acontrolled oxygen partial pressure.

  16. Calculation of the thermodynamic properties of the Ga–Sb–Tl liquid alloys

    Directory of Open Access Journals (Sweden)

    DRAGAN MANASIJEVIC

    2005-02-01

    Full Text Available The results of the calculation of the thermodynamic properties for liquid Ga–Sb–Tl alloys at the temperature 1073 K are presented in this paper. Initially, the most appropriate thermodynamic model for the investigated system was selected. Based on a comparison of the values calculated by different geometric models (Kohler, Muggianu, Toop, Hillert, Chou with the existing experimental based data, asymmetric models of calculation were determined to give the best results. The asymmetric nature of the investigated ternary system was additionally confirmed by the Chou similarity coefficient concept. For these reasons, further complete thermodynamic calculations were performed according to the Hillert model in five sections of the ternary Ga–Sb–Tl system from each corner with the mole ratio of other two components being 9:1; 7:3; 5:5; 3:7 and 1:9. The obtained results include integral excess Gibbs energy dependences on composition for all the investigated sections. The calculated activity values at 1073 K for all components are given in the form of isoactivity diagrams. Comparison between the calculated and experimentally obtained gallium activities shows good agreement.

  17. Magnetic properties of ferritin and akaganeite nanoparticles in aqueous suspension

    Energy Technology Data Exchange (ETDEWEB)

    Koralewski, Marceli, E-mail: koral@amu.edu.pl; Pochylski, Mikolaj; Gierszewski, Jacek [Adam Mickiewicz University, Optics Laboratory, Faculty of Physics (Poland)

    2013-09-15

    We have studied the magnetically induced optical birefringence {Delta}n of horse spleen ferritin (HSF) and aqueous suspensions of several different-sized iron oxyhydroxide nanoparticles coated with different polysaccharides mimicking ferritin. The structure and dimensions of the akaganeite mineral core were characterized by XRD and TEM, respectively. The stability of the suspensions in the measurement temperature range from 278 to 358 K was confirmed by UV-Vis absorption spectroscopy. The values of optical polarizability anisotropy {Delta}{alpha}, magnetic susceptibility anisotropy {Delta}{chi}, and permanent magnetic dipole moment {mu}{sub m} of the akaganeite nanoparticles have been estimated on the basis of the temperature dependence of the Cotton-Mouton (C-M) constant. The magnetic birefringence of Fe-sucrose has been described tentatively by different types of Langevin function allowing another estimation of {Delta}{chi} and {mu}{sub m}. The obtained permanent magnetic dipole moment {mu}{sub m} of the studied akaganeite nanoparticles proves small and comparable to that of HSF. The value of {mu}{sub m} is found to increase with decreasing nanoparticle diameter. Observed in a range spanning more than five orders of magnitude, the linear relation between the C-M constant and the iron concentration provides a basis for possible analytical application of the C-M effect in biomedicine. The established relation between the C-M constant and the nanoparticle diameter confirms that the dominant contribution to the measured magnetic birefringence comes from the magnetic susceptibility anisotropy {Delta}{chi}. A comparison of the C-M constants of the studied akaganeite nanoparticles with the data obtained for HSF provides evidence that the ferritin core behaves as a non-Euclidian solid.

  18. Equilibrium, thermodynamic and kinetic studies for the biosorption of aqueous lead(II) ions onto the seed husk of Calophyllum inophyllum

    International Nuclear Information System (INIS)

    Biosorption of lead(II) ions from aqueous solution onto the seed husk of Calophyllum inophyllum was investigated in a batch system. Equilibrium, thermodynamics and kinetic studies were conducted by considering the effects of pH, initial metal ion concentration, contact time, and temperature. The results showed that the uptake of the metal ions increased with increase in initial metal ion concentration. The pH for optimum adsorption was 4 for the Pb(II) ions (q = 4.86 mg/g and 97.2% adsorption). Langmuir isotherm described the biosorption of Pb(II) ions onto the biomass (R2 = 0.9531) better than the Freundlich model (R2 = 0.7984), and the Temkin model (R2 = 0.8761). Biosorption kinetics data obtained for the metal ions sorption were fitted using pseudo-first-order and pseudo-second-order. It was found that the kinetics data fitted well into the pseudo-second-order kinetics. Thermodynamic parameters such as Gibbs free energy (ΔG), standard enthalpy (ΔH) and standard entropy (ΔS) were evaluated. The result showed that biosorption of the metal ion onto C. inophyllum biomass was spontaneous and endothermic in nature. The results of FTIR (Fourier-transform infrared spectroscopy) revealed that carboxyl, amine, and hydroxyl groups on the biomass surface were involved in the adsorption of Pb(II) ions.

  19. One-step synthesized calcium phosphate-based material for the removal of alizarin S dye from aqueous solutions: isothermal, kinetics, and thermodynamics studies

    Science.gov (United States)

    Adeogun, Abideen Idowu; Babu, Ramesh Balakrishnan

    2015-07-01

    Calcium phosphate hydroxyapatite (Ca-Hap) synthesized from CaCO3 and H3PO5, it was characterized by scanning electron microscopy, Fourier transform infrared, and X-ray diffraction. The Ca-Hap was used for the removal of Alizarin Red S dye from its aqueous solution. The kinetics, equilibrium, and thermodynamic of the adsorption of the dye onto the Ca-Hap were investigated. The effects of contact time, initial dye concentration, pH as well as temperature on adsorption capacity of Ca-Hap were studied. Experimental data were analyzed using six model equations: Langmuir, Freudlinch, Redlich-Peterson, Temkin, Dubinin-Radushkevich, and Sips isotherms and it was found that the data fitted well with Sips and Dubinin-Radushkevich isotherm models. Pseudo-first-order, pseudo-second-order, Elovic, and Avrami kinetic models were used to test the experimental data in order to elucidate the kinetic adsorption process and it was found that pseudo-second-order model best fit the data. The calculated thermodynamics parameters (∆G°, ∆H° and ∆S°) indicated that the process is spontaneous and endothermic in nature.

  20. Kinetics and thermodynamics of adsorption of ionizable aromatic compounds from aqueous solutions by as-prepared and oxidized multiwalled carbon nanotubes

    International Nuclear Information System (INIS)

    The adsorption of 1-naphthylamine, 1-naphthol and phenol on as-prepared and oxidized multiwalled carbon nanotubes (MWCNTs) has been investigated. The results illustrated that both as-prepared and oxidized MWCNTs showed high adsorption capacity for the three ionizable aromatic compounds (IACs) studied. Oxidation of MWCNTs increased the surface area and the pore volume, and introduced oxygen-containing functional groups to the surfaces of MWCNTs, which depressed the adsorption of IACs on MWCNTs. Both Langmuir and Freundlich models described the adsorption isotherms very well and the adsorption thermodynamic parameters (ΔGo, ΔHo and ΔSo) were measured. The adsorption for 1-naphthylamine, 1-naphthol and phenol is general spontaneous and thermodynamically favorable. The adsorption of phenol is an exothermic process, whereas the adsorption of 1-naphthylamine and 1-naphthol is an endothermic process. Results of this work are of great significance for the environmental application of MWCNTs for the removal of IACs from large volume of aqueous solutions.

  1. The removal of the indigo carmine dye from aqueous solutions using cross-linked chitosan-Evaluation of adsorption thermodynamics using a full factorial design

    International Nuclear Information System (INIS)

    A 23 factorial design was employed to evaluate the quantitative removal of the indigo carmine (IC) dye from aqueous solutions on glutaraldehyde cross-linked chitosan. The variables were chitosan masses of 100 and 300 mg, IC concentrations of 2.0 and 5.0 x 10-5 mol L-1 and temperatures of 25 and 35 deg. C. The quantitative and energetic adsorption parameters were analyzed statistically using modeling with bilinear equations. The results indicated that increasing the chitosan mass from 100 to 300 mg decreases the IC adsorption/mass ratio (mol g-1) whereas a temperature increase of 25-35 deg. C increases it. The principal effect of the IC concentration did not show statistical significance. The factorial experiments demonstrate the existence of a significant antagonistic interaction effect between the chitosan mass and temperature. The adsorption thermodynamic parameters, namely ΔadsH, ΔadsG, and ΔadsS, were determined for all the factorial design results. Endothermic values were found in relation to the ΔadsH. The positive ΔadsS values indicate that entropy is a driving force for adsorption. The ΔadsG values are also significantly affected by important antagonistic and synergistic effects involving all principal and interactive factors. It is concluded that the thermodynamical spontaneity of the IC adsorption parameters are greatly influenced by the interactive factors and not by the temperature changes alone

  2. Equilibrium, kinetics and thermodynamics studies of chitosan-based solid phase nanoparticles as sorbent for lead (II) cations from aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Shaker, Medhat A., E-mail: drmashaker@yahoo.com [Current address: Chemistry Department, Faculty of Science, University of Jeddah, Jeddah (Saudi Arabia); Permanent address: Chemistry Department, Faculty of Science, Damanhour University, Damanhour (Egypt)

    2015-07-15

    Ternary nanoparticles of chitosan, non-viable biomass (Pseudomonas sp.) and gelatin, CPG were synthesized by chemical crosslinking method and applied as a novel and cost-effective solid phase to adsorb Pb(II) cations from aqueous solution. Characterization of the fabricated CPG nanoparticles and their complexation behavior were extensively interrogated by dynamic light scattering (DLS), FTIR, TGA, XRD and SEM techniques. The extent of adsorption was found to be a function of medium pH, contact time, initial Pb(II) concentration and temperature. The Langmuir, Freundlich, Dubinin–Radushkevich and Redlich–Peterson models were used to illustrate the isotherms of the adsorption system. The adsorption of Pb(II) cations onto CPG best-fits the Langmuir isotherm model which predicts two stoichiometric temperature-independent adsorption sites, A and B with variable capacities, 35.4 and 91.1 mg g{sup −1}, respectively and removal capacity above 90%. Thermodynamic studies revealed that the adsorption process was physical, spontaneous, and endothermic. The adsorption rate is influenced by temperature and the adsorption kinetic is well confirmed with pseudo-second-order equation compared with three other investigated kinetic models. Present study indicated potential applications of CPG nanoparticles as excellent natural and promising solid phase for Pb(II) extraction in wastewater treatment. - Graphical abstract: Display Omitted - Highlights: • Kinetics and thermodynamics of Pb{sup 2+} biosorption onto CPG nanoparticles are studied. • Adsorption kinetic data are best modeled using second-order rate equations. • The Pb{sup 2}adsorption onto CPG was physical diffusion controlled reaction. • The experimental equilibrium results well fit the Langmuir model. • The thermodynamics show endothermic, favorable and spontaneous adsorption processes.

  3. Equilibrium, kinetics and thermodynamics studies of chitosan-based solid phase nanoparticles as sorbent for lead (II) cations from aqueous solution

    International Nuclear Information System (INIS)

    Ternary nanoparticles of chitosan, non-viable biomass (Pseudomonas sp.) and gelatin, CPG were synthesized by chemical crosslinking method and applied as a novel and cost-effective solid phase to adsorb Pb(II) cations from aqueous solution. Characterization of the fabricated CPG nanoparticles and their complexation behavior were extensively interrogated by dynamic light scattering (DLS), FTIR, TGA, XRD and SEM techniques. The extent of adsorption was found to be a function of medium pH, contact time, initial Pb(II) concentration and temperature. The Langmuir, Freundlich, Dubinin–Radushkevich and Redlich–Peterson models were used to illustrate the isotherms of the adsorption system. The adsorption of Pb(II) cations onto CPG best-fits the Langmuir isotherm model which predicts two stoichiometric temperature-independent adsorption sites, A and B with variable capacities, 35.4 and 91.1 mg g−1, respectively and removal capacity above 90%. Thermodynamic studies revealed that the adsorption process was physical, spontaneous, and endothermic. The adsorption rate is influenced by temperature and the adsorption kinetic is well confirmed with pseudo-second-order equation compared with three other investigated kinetic models. Present study indicated potential applications of CPG nanoparticles as excellent natural and promising solid phase for Pb(II) extraction in wastewater treatment. - Graphical abstract: Display Omitted - Highlights: • Kinetics and thermodynamics of Pb2+ biosorption onto CPG nanoparticles are studied. • Adsorption kinetic data are best modeled using second-order rate equations. • The Pb2adsorption onto CPG was physical diffusion controlled reaction. • The experimental equilibrium results well fit the Langmuir model. • The thermodynamics show endothermic, favorable and spontaneous adsorption processes

  4. Rapid Computation of Thermodynamic Properties over Multidimensional Nonbonded Parameter Spaces Using Adaptive Multistate Reweighting.

    Science.gov (United States)

    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

  5. Comparative study of the physicochemical properties of aqueous solutions of the hydrocarbon and fluorocarbon surfactants and their ternary mixtures

    International Nuclear Information System (INIS)

    Highlights: • Acoustic properties of hydrocarbon and fluorocarbon surfactants were studied. • Auerbach’s relation is not proper for mixtures with fluorocarbon surfactants. • Values of the hydration number decreases at concentrations higher than CMC. • FSO100 and its mixtures are the strongest chaotropes. - Abstract: Speed of sound and density of aqueous solutions of hydrocarbon p-(1,1,3,3-tetramethylbutyl) phenoxypoly(ethyleneglycols) (Triton X-100 (TX100), Triton X-165 (TX165)) and fluorocarbon (Zonyl FSN-100 (FSN100), Zonyl FSO-100 (FSO100)) surfactants as well as their ternary mixtures were measured at 293 K. Taking into account these values and the literature data of the surface tension and viscosity of the studied systems, the values of the isentropic compressibility, apparent specific adiabatic compressibility, hydration number, apparent specific volume and Jones Dole’s A and B-coefficients were determined. For the systems containing FSO100 also the values of dB/dT were determined on the basis of the values of viscosity measured at different temperatures. Next, the calculated thermodynamic properties have been discussed in the term of intermolecular interactions between the components of the mixtures

  6. Influence of Deacetylation on the Rheological Properties of Xanthan-Guar Interactions in Dilute Aqueous Solutions

    Science.gov (United States)

    An oscillating capillary rheometer was used to investigate the effects of xanthan deacetylation on the viscoelastic properties and intrinsic viscosity of xanthan and guar mixtures in dilute aqueous solutions. Deacetylated xanthan exhibited a stronger synergistic interaction with guar than native xan...

  7. Experimentally determined thermodynamic properties of schapbachite (α-AgBiS2) below T = 700 K

    International Nuclear Information System (INIS)

    Highlights: • A galvanic cell incorporating AgI as the solid electrolyte was measured accurately. • Thermodynamics of the phase assemblage AgBiS2–AgBi3S5–Bi have been investigated. • ΔfG∘ values for bismuth-saturated schapbachite (α-AgBi1+xS2) have been determined. • New experimental thermodynamic data for Bi-saturated schapbachite were generated. • ΔrG∘ values for reactions involving S2(g) to produce α-AgBi1+xS2 have been evaluated. -- Abstract: Thermodynamic properties of schapbachite (α-AgBiS2) in the phase assemblage α-AgBiS2–AgBi3S5–Bi have been studied by an EMF-technique. The EMF-measurements were made on the galvanic cell Pt(−)|Ag|AgI|AgBiS2 + AgBi3S5 + Bi|C|Pt(+), over the temperature range from (429 to 699) K. According to the EMF vs. temperature relations obtained, the enthalpy of the phase transformation from β-AgBi1+xS2 to α-AgBi1+xS2, at T = (465.55 ± 5) K, was calculated to be (7.3 ± 2.1) kJ · mol−1. New experimentally determined thermodynamic properties of the bismuth-saturated schapbachite (α-AgBi1+xS2), for each temperature region of the stable phases Bi(s) and Bi(l), were generated and analysed in detail. Based on the experimental results, Gibbs free energies of sulfidation reactions including Ag, Bi(l), S2(g), Ag2S and Bi2S3 to produce the bismuth-saturated schapbachite (α-AgBi1+xS2) have been evaluated. It has been observed that within the temperature range from (474 to 680) K, schapbachite saturated with bismuth (α-AgBi1+xS2) is thermodynamically more stable than the stoichiometric schapbachite (α-AgBiS2)

  8. Electrocoagulation removal of anthraquinone dye Alizarin Red S from aqueous solution using aluminum electrodes: kinetics, isothermal and thermodynamics studies

    OpenAIRE

    Adeogun, Abideen Idowu; Balakrishnan, Ramesh Babu

    2016-01-01

    Electrocoagulation (EC) was used for the removal of anthraquinone dye, Alizarin Red S (ARS) from aqueous solution. The process was carried out in a batch electrochemical cell with Al electrodes in a monopolar connection. The effects of some important parameters such as current density, pH, temperature and initial dye concentration, on the process were investigated. Equilibrium was attained after 10 minutes at 30 °C. Pseudo-first order, pseudo-second order, Elovic, and Avrami kinetic models we...

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

    Energy Technology Data Exchange (ETDEWEB)

    Shvab, I.; Sadus, Richard J., E-mail: rsadus@swin.edu.au [Centre for Molecular Simulation, Swinburne University of Technology, PO Box 218, Hawthorn, Victoria 3122 (Australia)

    2013-11-21

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

  10. Thermodynamic Properties and Transport Coefficients of Nitrogen, Hydrogen and Helium Plasma Mixed with Silver Vapor

    Science.gov (United States)

    Zhou, Xue; Cui, Xinglei; Chen, Mo; Zhai, Guofu

    2016-05-01

    Species composites of Ag-N2, Ag-H2 and Ag-He plasmas in the temperature range of 3,000-20,000 K and at 1 atmospheric pressure were calculated by using the minimization of Gibbs free energy. Thermodynamic properties and transport coefficients of nitrogen, hydrogen and helium plasmas mixed with a variety of silver vapor were then calculated based on the equilibrium composites and collision integral data. The calculation procedure was verified by comparing the results obtained in this paper with the published transport coefficients on the case of pure nitrogen plasma. The influences of the silver vapor concentration on composites, thermodynamic properties and transport coefficients were finally analyzed and summarized for all the three types of plasmas. Those physical properties were important for theoretical study and numerical calculation on arc plasma generated by silver-based electrodes in those gases in sealed electromagnetic relays and contacts. supported by National Natural Science Foundation of China (Nos. 51277038 and 51307030)

  11. Highly efficient molecular simulation methods for evaluation of thermodynamic properties of crystalline phases

    Science.gov (United States)

    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

  12. Elastic and thermodynamic properties of c-BN from first-principles calculations

    Institute of Scientific and Technical Information of China (English)

    Hao Yan-Jun; Cheng Yan; Wang Yan-Ju; Chen Xiang-Rong

    2007-01-01

    The elastic constants and thermodynamic properties of c-BN are calculated using the first-principles plane wave method with the relativistic analytic pseudopotential of the Hartwigen, Goedecker and Hutter (HGH) type in the frame of local density approximation and using the quasi-harmonic Debye model, separately. Moreover, the dependences of the normalized volume V/V0 on pressure P, as well as the bulk modulus B, the thermal expansion α, and the heat capacity CV on pressure P and temperature T are also successfully obtained.

  13. Thermodynamic and transport properties of SmS under high pressure

    International Nuclear Information System (INIS)

    We measured transport and thermodynamic properties of the valence-fluctuating phase of SmS up to 8.5 kbar, and found a bump structure in the temperature dependence of the electrical resistivity and a Schottky-type anomaly in the temperature dependence of the thermal expansion coefficient at a characteristic temperature T0. We also observed that the absolute value of the Hall constant rapidly increases below T0. From these results, we argue that the steep rise of the electrical resistivity below T0 is inherent to golden SmS and can be ascribed to the decrease in the carrier concentration possibly due to the pseudo gap formation.

  14. Thermodynamic properties of metal amides determined by ammonia pressure-composition isotherms

    OpenAIRE

    Hino, Satoshi; Ichikawa, Takayuki; Kojima, Yoshitsugu

    2010-01-01

    Thermodynamic properties of Mg(NH2)(2) and LiNH2 were investigated by measurements of NH3 pressure-composition isotherms (PCI). Van't Hoff plot of plateau pressures of PCI for decomposition of Mg(NH2)(2) indicated the standard enthalpy and entropy change of the reactions were Delta H degrees = (120 +/- 11) kJ . mol(-1) (per unit amount of NH3) and Delta S degrees= (182 +/- 19) J . mol(-1) . K-1 for the reaction: Mg(NH2)(2) -> MgNH +NH3, and Delta H degrees= 112 kJ . mol(-1) and Delta S degree...

  15. Thermodynamic properties of a solid exhibiting the energy spectrum given by the logistic map

    International Nuclear Information System (INIS)

    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)

  16. Phonon Dispersion and Thermodynamics Properties of CaF2 via Shell Model Molecular Dynamics Simulations

    Institute of Scientific and Technical Information of China (English)

    CHENG Yan; HU CuiE; ZENG Zhao-Yi; GONG Min; GOU Qing-Quan

    2009-01-01

    The phonon and thermodynamics properties of face-centered cubic CaF2 at high pressure and high tem-perature are investigated by using the shell model interatomic pair potential within General Utility Lattice Program (GULP). The phonon dispersion curves and the corresponding density of state (PDOS) in this work are consistent with the experimental data and other theoretical results. The transverse optical (TO) and longitudinal optical (LO) mode splitting as well as heat capacity at constant volume Cv and entropy S versus pressure and temperature are also obtained.

  17. Thermodynamic properties of cubic ZrC under high pressure from first-principles calculations

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The elastic and thermodynamic properties of Zirconium carbide (ZrC) are investigated by ab initio plane-wave pseudopotential density function theory method. The obtained lattice constant, elastic constant and bulk modulus B are consistent with the experimental and theoretical data. Through the quasi-harmonic Debye model, the dependences of the normalized volume V/V0 and the bulk modulus B on pressure P, as well as the specific heat CV on the temperature T are obtained successfully. The relationships of the thermal expansion α with temperature and pressure are also investigated, which indicate the temperature hardly has any effect on the thermal expansion α at high pressure.

  18. First-Principle Calculations for Elastic and Thermodynamic Properties of Diamond

    Institute of Scientific and Technical Information of China (English)

    FU Zhi-Jian; JI Guang-Fu; CHEN Xiang-Rong; GOU Qing-Quan

    2009-01-01

    The elastic constants and thermodynamic properties of diamond are investigated by using the CRYSTAL03 ture are obtained. The results are in good agreement with the available experimental and theoretical data. Moreover, the relationship between V/V0 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.

  19. First-principles investigation of the electronic, elastic and thermodynamic properties of VC under high pressure

    Institute of Scientific and Technical Information of China (English)

    Hao Ai-Min; Zhou Tie-Jun; Zhu Yan; Zhang Xin-Yu; Liu Ri-Ping

    2011-01-01

    An investigation of the electronic, elastic and thermodynamic properties of VC under high pressure has been conducted using first-principles calculations based on density functional theory (DFT)with the plane-wave basis set,as implemented in the CASTEP code. At elevated pressures, VC is predicted to undergo a structural transition from a relatively open NaCl-type structure to a more dense CsCl-type one. The predicted transition pressure is 520 GPa.The elastic constant, Debye temperature and heat capacity each as a function of pressure and/or temperature of VC are presented for the first time.

  20. Development of Characterization Techniques of Thermodynamic and Physical Properties Applied to the CO2-DMSO Mixture

    OpenAIRE

    Calvignac, Brice; Rodier, Elisabeth; Letourneau, Jean-Jacques; Fages, Jacques

    2009-01-01

    International audience This work is focused on the development of new characterization techniques of physical and thermodynamic properties. These techniques have been validated using the binary system DMSO-CO2 for which several studies of characterization have been well documented. We focused on the DMSO-rich phase and we carried out measurements of volumetric expansion, density, viscosity and CO2 solubility at 298.15, 308.15 and 313.15 K and pressures up to 9 MPa. The experimental procedu...

  1. Investigation of thermodynamic properties of molten rare earth trichlorides by molecular dynamics method

    International Nuclear Information System (INIS)

    The physical and thermodynamic properties of molten rare earth trichlorides were investigated by the molecular dynamics (MD) technique. In addition to a fully ionic model, partially ionic models, in which covalency was considered in the nearest unlike ion pair (cation-chloride ion), was used in the present work. The liquid structure, shear viscosity and enthalpy of molten YCl3 and LaCl3 calculated from the MD simulation were compared with the experimental data. It is concluded that the partially ionic model can better represent the experimental data than the fully ionic model. (orig.)

  2. Thermodynamic properties of noninteracting quantum gases with spin-orbit coupling

    Energy Technology Data Exchange (ETDEWEB)

    He Li [Jiangsu University of Science and Technology, Zhangjiagang, Jiangsu, 215600 (China); Yu Zengqiang [Institute for Advanced Study, Tsinghua University, Beijing, 100084 (China)

    2011-08-15

    In this brief report we study thermodynamic properties of noninteracting quantum gases with isotropic spin-orbit coupling. At high temperature, coefficients of virial expansion depend on both temperature T and spin-orbit coupling strength {kappa}. For strong coupling, virial expansion is applicable to the temperature region below the conventional degenerate temperature T{sub F}. At low temperature, specific heat is proportional to {radical}(T) in Bose gases and T in Fermi gases. Temperature dependence of the chemical potential of fermions shows a different behavior when the Fermi surface is above and below the Dirac point.

  3. Thermodynamic Properties of ZnO With in Mie-Grüneisen Hypothesis

    Directory of Open Access Journals (Sweden)

    A.D. Patel

    2011-01-01

    Full Text Available Zink oxide (mineral name: Zincite is an attractive wide band gap semiconductor due to its large number of industrial applications such as in the production of solar cells, liquid-crystal displays, electrochromic devices, LED, as well as adhesive taps, automobile tires, ceramics, glass, varistors, etc. It is due to versatile nature of ZnO, in we have studied its thermal properties at high temperatures. Theoretically, complete ab initio investigations at elevated temperatures are restricted due largely to computational complexity of many-body nature. We have therefore used an consistent iterative scheme to include thermal effect by combining the universal equation of state (UEOS to the Mie-Gruneisen hypothesis. It is demonstrated that from the knowledge of cohesive properties at ambient condition various thermodynamic properties can be predicted at finite temperatures and pressures. For example, presently calculated relative volume-thermal expansions, static EOS are in good accordance with experimental results.

  4. The thermodynamic properties of liquid melts in the Fe - S and Fe - S - metal systems

    International Nuclear Information System (INIS)

    Thermodynamic properties of the molten Fe - S, Fe - S - M (M = Ti, Zr, Hf, Nb, Ta, Cr, Mo, W, Ce, La, Al) systems were investigated with the aim of finding a desulfurization ability of some d- and f-metals using calorimetry. Several conclusions on desulfurization properties of the d- and f-metals in iron based sulfur-containing alloys were made. It was established that partial molar enthalpies of the metals were changed essentially for the majority of them on addition of some metals in sulfur-containing solutions. Desulfurization properties of the metals were shown to rise in the row: Mo → Cr → Mn → Nb → Ta → Ti → Zr → Hf → La → Ce for the Fe - S - M ternary molten systems

  5. Experimental Measurement and Thermodynamic Modeling of the Solubility of Carbon Dioxide in Aqueous Alkanolamine Solutions in the High Gas Loading Region

    Science.gov (United States)

    Suleman, Humbul; Maulud, Abdulhalim Shah; Man, Zakaria

    2016-09-01

    The solubility of carbon dioxide in aqueous alkanolamine solutions was investigated in the high gas loading region based on experimental measurements and thermodynamic modeling. An experimental phase equilibrium study was performed to evaluate the absorption of carbon dioxide in aqueous solutions of five representative alkanolamines, including monoethanolamine, diethanolamine, N-methyldiethanolamine, 2-amino-2-methyl-1-propanol and piperazine. The carbon dioxide loadings of these solutions were determined for a wide range of pressures (62.5 kPa to 4150 kPa), temperatures (303.15 K to 343.15 K) and alkanolamine concentrations (2 M to 4 M). The results were found to be largely consistent with those previously reported in the literature. Furthermore, a hybrid Kent-Eisenberg model was developed for the correlation of the experimental data points. This new model incorporated an equation of state/excess Gibbs energy model for determining the solubility of carbon dioxide in the high-pressure-high gas loading region. This approach also used a single correction parameter, which was a function of the alkanolamine concentration. The results of this model were in excellent agreement with our experimental results. Most notably, this model was consistent with other reported values from the literature.

  6. Influence of the composition of aqueous-alcohol solvents on the thermodynamic characteristics of L-phenylalanine dissolution at 298.15 K

    Energy Technology Data Exchange (ETDEWEB)

    Badelin, Valentin G. [Laboratory of Thermodynamics of Solutions of Non-electrolytes and Biologically Active Substances, Institute of Solution Chemistry, Russian Academy of Sciences, 1 Akademicheskaya Street, 153045, Ivanovo (Russian Federation); Smirnov, Valeriy I., E-mail: vis@isc-ras.ru [Laboratory of Thermodynamics of Solutions of Non-electrolytes and Biologically Active Substances, Institute of Solution Chemistry, Russian Academy of Sciences, 1 Akademicheskaya Street, 153045, Ivanovo (Russian Federation)

    2011-11-10

    Highlights: Black-Right-Pointing-Pointer Enthalpies of L-phenylalanine dissolution have been measured in aqueous methanol, ethanol, 1-propanol and 2-propanol. Black-Right-Pointing-Pointer The measured data were reported as functions of composition of water + alcohol mixtures. Black-Right-Pointing-Pointer Enthalpy coefficients of pair-wise interactions have been analyzed in terms of McMillan-Mayer theory. Black-Right-Pointing-Pointer A comparative analysis of the characteristics of dissolution of L-phenylalanine and some other L-amino acids in the similar systems has been made. - Abstract: The enthalpies of L-phenylalanine dissolution in aqueous methanol, ethanol, 1-propanol and 2-propanol have been determined by calorimetry at 298.15 K and alcohol mole fractions up to x{sub 2} {approx}0.4. The standard enthalpies of solution {Delta}{sub sol}H Degree-Sign and transfer {Delta}{sub tr}H Degree-Sign from water to the mixed solvent as well as the enthalpy coefficients of L-phenylalanine-alcohol pair-wise interactions were calculated. The interrelation of the enthalpies of dissolution and transfer for L-phenylalanine with structural features of alcohols has been determined. A comparative analysis of the thermodynamic characteristics of dissolution of L-phenylalanine and some other amino acids (glycine, L-alanine, L-threonine and L-valine) in the mixtures studied has been made.

  7. Comparisons of kinetics, thermodynamics and regeneration of tetramethylammonium hydroxide adsorption in aqueous solution with graphene oxide, zeolite and activated carbon

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Shenteng; Lu, Chungsying, E-mail: clu@nchu.edu.tw; Lin, Kun-Yi Andrew

    2015-01-30

    Graphical abstract: A comparison of TMAH adsorption capacity with GO, NaY and GAC is conducted and the result reveals that the magnitude of qe follows the order of GO > NaY > GAC. The adsorption capacity of GO is significantly higher than those of zeolite and activated carbon in this and reported studies, showing its encouraging potential. GO also exhibits good reversibility of TMAH adsorption through 10 cycles of adsorption and desorption process. This reflects that GO is a promising and efficient adsorbent for TMAH removal in wastewater treatment. - Highlights: • Adsorption kinetics and isotherms of TMAH to GO, NaY and GAC are compared. • Thermodynamics of TMAH adsorption to GO, NaY and GAC is determined. • GO exhibits the highest TMAH adsorption capacity, followed by NaY and GAC. • Recyclabilities of NaY and GO remain above 95% but that of GAC dropped to 70%. - Abstract: Graphene oxide (GO), sodium Y-type zeolite (NaY) and granular activated carbon (GAC) are selected as adsorbents to study their kinetics, thermodynamics and regeneration of tetramethylammonium hydroxide (TMAH) adsorption from water. The adsorption kinetics follows the pseudo-second-order rate law while the adsorption thermodynamics shows an exothermic reaction with GO and GAC but displays an endothermic reaction with NaY. The adsorbed TMAH can be readily desorbed from the surface of GO and NaY by 0.05 M NaCl solution. A comparative study on the cyclic TMAH adsorption with GO, NaY and GAC is also conducted and the results reveal that GO exhibits the greatest TMAH adsorption capacity as well as superior reversibility of TMAH adsorption over 10 cycles of adsorption and desorption process. These features indicate that GO is a promising and efficient adsorbent for TMAH removal in wastewater treatment.

  8. Comparisons of kinetics, thermodynamics and regeneration of tetramethylammonium hydroxide adsorption in aqueous solution with graphene oxide, zeolite and activated carbon

    International Nuclear Information System (INIS)

    Graphical abstract: A comparison of TMAH adsorption capacity with GO, NaY and GAC is conducted and the result reveals that the magnitude of qe follows the order of GO > NaY > GAC. The adsorption capacity of GO is significantly higher than those of zeolite and activated carbon in this and reported studies, showing its encouraging potential. GO also exhibits good reversibility of TMAH adsorption through 10 cycles of adsorption and desorption process. This reflects that GO is a promising and efficient adsorbent for TMAH removal in wastewater treatment. - Highlights: • Adsorption kinetics and isotherms of TMAH to GO, NaY and GAC are compared. • Thermodynamics of TMAH adsorption to GO, NaY and GAC is determined. • GO exhibits the highest TMAH adsorption capacity, followed by NaY and GAC. • Recyclabilities of NaY and GO remain above 95% but that of GAC dropped to 70%. - Abstract: Graphene oxide (GO), sodium Y-type zeolite (NaY) and granular activated carbon (GAC) are selected as adsorbents to study their kinetics, thermodynamics and regeneration of tetramethylammonium hydroxide (TMAH) adsorption from water. The adsorption kinetics follows the pseudo-second-order rate law while the adsorption thermodynamics shows an exothermic reaction with GO and GAC but displays an endothermic reaction with NaY. The adsorbed TMAH can be readily desorbed from the surface of GO and NaY by 0.05 M NaCl solution. A comparative study on the cyclic TMAH adsorption with GO, NaY and GAC is also conducted and the results reveal that GO exhibits the greatest TMAH adsorption capacity as well as superior reversibility of TMAH adsorption over 10 cycles of adsorption and desorption process. These features indicate that GO is a promising and efficient adsorbent for TMAH removal in wastewater treatment

  9. Optical properties of natural phenols in aqueous media

    Science.gov (United States)

    Vusovich, Olga; Sultimova, Natalia; Tchaikovskaya, Olga; Sokolova, Irina; Vasilieva, Nina

    2015-11-01

    Currently, the study of the photochemistry of natural phenols is relevant as it has a fundamental and a practical importance. The optical properties of natural phenols are studied: 3-methoxy-4-hydroxybenzaldehyde (vanillin) and 3- hydroxy-4-methoxybenzaldehyde (isovanillin), 4-hydroxy-3-methoxybenzoic acid (vanillic acid). The processes of proton transfer in the investigated molecules in ground and excited states under exposure to lamp and laser emissions are presented using the methods of electron spectroscopy and quantum chemistry.

  10. The influence of temperature and inorganic salts on therheological properties of xanthan aqueous solutions

    OpenAIRE

    KATARINA JEREMIC; SINISA MARKOV; BRANISLAV PEKIC; SLOBODAN JOVANOVIC; MIRJANA S. PAVLOVIC

    1999-01-01

    The rheological properties of xanthan gum in aqueous saline solutions and at increased temperatures are of great practical interest especially for its application in enhanced oil recovery during which the xanthan solutions are exposed to increased salt contents and relatively high temperatures. In this work, the influence of high temperature and high salt concentrations (up to 10 mass%) on the rheological properties of xanthan was investigated. The influence of three different salts was exami...

  11. Removal of ibuprofen, naproxen and carbamazepine in aqueous solution onto natural clay: equilibrium, kinetics, and thermodynamic study

    Science.gov (United States)

    Khazri, Hassen; Ghorbel-Abid, Ibtissem; Kalfat, Rafik; Trabelsi-Ayadi, Malika

    2016-04-01

    This study aimed to describe the adsorption of three pharmaceuticals compounds (ibuprofen, naproxen and carbamazepine) onto natural clay on the basis of equilibrium parameters such as a function of time, effect of pH, varying of the concentration and the temperature. Adsorption kinetic data were modeled using the Lagergren's first-order and the pseudo-second-order kinetic equations. The kinetic results of adsorption are described better using the pseudo-second order model. The isotherm results were tested in the Langmuir, Freundlich and Dubinin-Radushkevich models. The thermodynamic parameters obtained indicate that the adsorption of pharmaceuticals on the clay is a spontaneous and endothermic process.

  12. Efficacy of mangrove leaf powder for bioremediation of chromium (VI) from aqueous solutions: kinetic and thermodynamic evaluation

    Science.gov (United States)

    Sathish, Thadikamala; Vinithkumar, N. V.; Dharani, G.; Kirubagaran, R.

    2014-03-01

    Biosorption of heavy metals by bio-materials has been posited as a potential alternative to the existing physicochemical technologies for detoxification and recovery of toxic and valuable metals from wastewaters. In this context, the role of mangrove leaf powder (MLP) as biosorbent for chromium removal was investigated. In the present study, the effect of process parameters such as particle size, solution pH, initial concentration of Cr(VI) ion and adsorbent dose on chromium removal by MLP was investigated. The maximum sorption was observed at particle size 0.5 mm and pH 2.0. The adsorption data follow the pseudo second-order kinetics model. The isotherms denote that Langmuir model is the best fitted than Freundlich model. The maximum adsorption capacity (Q 0) of 60.24 mg/g of Cr(VI) at 30 min on MLP was determined using the Langmuir model. The adsorption isotherm model indicates that the chromium is adsorbing as monolayer on the surface of MLP with heterogeneous energetic distribution of active sites. Various thermodynamic parameters, such as Gibb's free energy (∆G °), enthalpy (∆H °) and entropy (∆S °) have been calculated. The thermodynamic data revealed that the adsorption of chromium ions onto MLP is endothermic in nature and a spontaneous process. The results of the present study suggest that MLP is an effective bioremediation measure for removal of high concentration of Cr(VI) in waste waters.

  13. Adsorption of Pb(II) ions from aqueous solution by native and activated bentonite: Kinetic, equilibrium and thermodynamic study

    International Nuclear Information System (INIS)

    In this study, the adsorption kinetics, equilibrium and thermodynamics of Pb(II) ions on native (NB) and acid activated (AAB) bentonites were examined. The specific surface areas, pore size and pore-size distributions of the samples were fully characterized. The adsorption efficiency of Pb(II) onto the NB and AAB was increased with increasing temperature. The kinetics of adsorption of Pb(II) ions was discussed using three kinetic models, the pseudo-first-order, the pseudo-second-order and the intra-particle diffusion model. The experimental data fitted very well the pseudo-second-order kinetic model. The initial sorption rate and the activation energy were also calculated. The activation energy of the sorption was calculated as 16.51 and 13.66 kJ mol-1 for NB and AAB, respectively. Experimental results were also analysed by the Langmuir, Freundlich and Dubinin-Redushkevich (D-R) isotherm equations at different temperatures. RL separation factor for Langmuir and the n value for Freundlich isotherm show that Pb(II) ions are favorably adsorbed by NB and AAB. Thermodynamic quantities such as Gibbs free energy (ΔG), the enthalpy (ΔH) and the entropy change of sorption (ΔS) were determined as about -5.06, 10.29 and 0.017 kJ mol-1 K-1, respectively for AAB. It was shown that the sorption processes were an endothermic reactions, controlled by physical mechanisms and spontaneously.

  14. Modelling uranium solubilities in aqueous solutions: Validation of a thermodynamic data base for the EQ3/6 geochemical codes

    International Nuclear Information System (INIS)

    Experimental solubilities of U4+ and UO22+ that are reported in the literature have been collected. Data on oxides, hydroxides and carbonates have been selected for this work. They include results both at 25 degrees C and at higher temperatures. The literature data have been compared with calculated uranium solubilities obtained with the EQ3/6 geochemical modelling programs and an uranium thermodynamic data base selected for the Swedish nuclear waste management program. This verification/validiation exercise has shown that more experimental data is needed to determine the chemical composition of anionic uranyl hydroxo complexes as well as their equilibrium constants of formation. There is also a need for more solubility data on well characterised alkaline or alkaline-earth uranates. For the uranyl carbonate system, the calculated results agree reasonably well with the experimental literature values, which span over a wide range of pH, (CO32-)T, CO2(g)-pressure, and T. The experimental solubility of UO2(s) agrees also well with the EQ3/6 calculations for pH greater than 6. However, in more acidic solutions the experimental solubilities are higher than the calculated values. This is due to the formation of polynuclear hydroxo complexes of uranium, which are not well characterised, and are not included in the thermodynamic data base used in this study. (authors)

  15. An Experimental Investigation on Rheological Properties of Aqueous Xanthan Gum as a Blood Analog Fluid

    Institute of Scientific and Technical Information of China (English)

    ZHANG Gen-guang; ZHANG Ming-yuan; YANG Wan-ying; ZHU Xian-ran

    2006-01-01

    Developing a shear thinning non-Newtonian fluid to substitute blood is desirable in studies of biomedicine engineering since blood is a shear thinning nonNewtonian fluid that exhibits both viscous and elastic properties, and generally not available in large volume. The rheological properties of aqueous Xanthan gum with different concentrations and temperatures were studied in present paper. The results show that aqueous Xanthan gum is a non-Newtonian fluid which displays remarkable shear thinning behaviour and is a suitable blood analog fluid. There is a power law distribution relationship between shear stress and shear rate, and the higher the solution concentration is, the more strongly it displays shear thinning behaviours. Viscosity values of aqueous Xanthan gum increase with the solution temperature decrease or with the solution concentration increase in linearity. Moreover at the temperature of 37℃, aqueous Xanthan gum with concentration of 0.4‰ and 0.6‰ matches human blood best in rheological properties. According to the resuits, the viscosity expression varied with temperature and concentrition is obtained, and the stability of Xanthan gum solution is discussed.

  16. An assessment of the thermodynamic properties of uranium nitride, plutonium nitride and uranium-plutonium mixed nitride

    International Nuclear Information System (INIS)

    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

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

    OpenAIRE

    Urrutia, Ignacio

    2016-01-01

    This work is devoted to analyze the relation between the thermodynamic properties of a confined fluid and the shape of its confining vessel. Recently, new insights in this topic were found through the study of cluster integrals for inhomogeneous fluids, that revealed the dependence on the vessel shape of the low density behavior of the system. Here, the statistical mechanics and thermodynamics of fluids confined in wedges or by edges is revisited, focusing on their cluster integrals. In parti...

  18. An equation of state for use with sodium. Part 1 - theory and computer program. Part 2 - tables of thermodynamic properties. Part 3 - tables of thermodynamic properties

    International Nuclear Information System (INIS)

    An equatuion of state has been produced which covers the entire P.V.T. diagram. Thermodynamic consistency has been maintained at all times. The thermodynamic data are presented in the forms of tables and a temperature-entropy chart. A computer program has been written to produce the tables and can also be built into other computer programs. (author)

  19. Biosorption of lanthanum and cerium from aqueous solutions using tangerine (Citrus reticulata) peel: Equilibrium, kinetic, and thermodynamic studies

    OpenAIRE

    Torab-Mostaedi Meisam

    2013-01-01

    Biosorption of lanthanum (III) and cerium (III) from aqueous solution by tangerine (Citrus reticulate) peel has been investigated in a batch system as a function of pH, biosorbent dosage, contact time, and temperature. The equilibrium pH was found to severely affect the biosorption performance; pH 5.0 is found to be an optimum pH for favorable biosorption of La (III) and Ce (III). The biosorption of lanthanum and cerium was investigated by the Langmuir, Freundlich and Dubinin-Radushkevi...

  20. Thermodynamic modelling of phase equilibrium for water + poly(Ethylene glycol + salt aqueous two-phase systems

    Directory of Open Access Journals (Sweden)

    R.A.G. Sé

    2002-04-01

    Full Text Available The NRTL (nonrandom, two-liquid model, expressed in mass fraction instead of mole fraction, was used to correlate liquid-liquid equilibria for aqueous two-phase polymer-salt solutions. New interaction energy parameters for this model were determined using reported data on the water + poly(ethylene glycol + salt systems, with different molecular masses for PEG and the salts potassium phosphate, sodium sulfate, sodium carbonate and magnesium sulfate. The correlation of liquid-liquid equilibrium is quite satisfactory.

  1. Preparation,characterization and properties studies of quinine-imprinted polymer in the aqueous phase

    Institute of Scientific and Technical Information of China (English)

    He Jianfeng; Liu Lan; Yang Guilan; Deng Qinying

    2006-01-01

    The uniform-sized spherical molecularly imprinted polymers were successfully prepared through molecular imprinting technology by two-step seed swelling and mini-emulsion polymerization in the aqueous condition using quinine as template molecules and methacrylic acid (MAA)as functional monomer.The polymers were characterized by IR spectra,thermal-weight analysis,scanning electron microscope and laser particle size analysis.The properties of imprinted polymers were investigated in different organic phases and aqueous media.In the organic media,results suggested that polar interactions(hydrogen bonding,ionic interactions)between acidic monomer/polymer and template molecules are mainly responsible for the binding and recognition;whereas in the aqueous medium,a considerable recognition effect was also obtained where the ionic(electrostatic)interaction and hydrophobic interaction play an important role.The experiments of binding different substrates indicated that the MIPs possessed an excellent rebinding ability and inherent selectivity to quinine.

  2. Study of structural, elastic, electronic and thermodynamic properties of NaAlO{sub 3}-perovskite

    Energy Technology Data Exchange (ETDEWEB)

    Bouafia, H. [Laboratoire de Microscope Electronique et Sciences des Materiaux, departement de physique, USTO, BP1505 El m' naouar, Oran (Algeria); Sahli, B. [Laboratoire de Genie Physique, Universite Ibn-Khaldoun, Tiaret 14000 (Algeria); Hiadsi, S. [Laboratoire de Microscope Electronique et Sciences des Materiaux, departement de physique, USTO, BP1505 El m' naouar, Oran (Algeria); Abidri, B., E-mail: b_abidri@hotmail.com [Laboratoire des Materiaux Magnetiques, Universite Djillali Liabes, Sidi Bel-Abbes 22000 (Algeria); Rached, D. [Laboratoire des Materiaux Magnetiques, Universite Djillali Liabes, Sidi Bel-Abbes 22000 (Algeria); Amrani, B. [Departement de Physique, Universite d' Oran es-senia (Algeria)

    2012-06-15

    The structural, elastic, electronic, and thermodynamic properties of the cubic NaAlO{sub 3}-perovskite are calculated using the full potential linearized augmented plane wave with local orbital (FP-LAPW)+lo. The exchange-correlation energy, is treated in generalized gradient approximation (GGA) using the Perdew-Burke-Ernzerhof (PBE) parameterization. The calculated equilibrium parameter is in good agreement with other works. The bulk modulus, elastic constants and their related parameters, such as Young modulus, shear modulus, and Poisson ratio were predicted. 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 NaAlO{sub 3}-perovskite exhibit a wide-gap which it is an indirect from R to {Gamma} point. The analysis of the density of states (DOS) curves shows ionic and covalent character bond for Al-O and Na-O respectively. To complete the fundamental characterization of NaAlO{sub 3} material we have analyzed the thermodynamic properties using the quasi-harmonic Debye model.

  3. Thermodynamic Properties of Liquid Silver-Antimony-Tin Alloys Determined from Electrochemical and Calorimetric Measurements

    Science.gov (United States)

    Łapsa, Joanna; Onderka, Bogusław

    2016-05-01

    The thermodynamic properties of liquid Ag-Sb-Sn alloys were obtained through use of the drop solution calorimetric method and electromotive force (emf) measurements of galvanic cells with a yttria stabilized zirconia (YSZ) solid electrolyte. The experiments were carried out along Ag0.25Sb0.75, Ag0.5Sb0.5 and Ag0.75Sb0.25 sections of the ternary system in the temperature range from 973 K to 1223 K. From the measured emf, the tin activity in liquid solutions of Ag-Sb-Sn was determined for the first time. The partial and integral enthalpy of mixing were determined from calorimetric measurements at two temperatures. These measurements were performed along two cross-sections: Sb0.5Sn0.5 at 912 K and 1075 K, and Ag0.75Sb0.25 at 1075 K. Both experimental data sets were used to find ternary interaction parameters by applying the Redlich-Kister-Muggianu model of the substitutional solution. Consequently, the set of parameters describing the thermodynamic properties of the liquid phase was derived.

  4. Molecular dynamics simulation study of thermodynamic and mechanical properties of the Cu-Pd random alloy

    International Nuclear Information System (INIS)

    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 Cu3Pd and CuPd3 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.

  5. Thermodynamic Properties of Liquid Silver-Antimony-Tin Alloys Determined from Electrochemical and Calorimetric Measurements

    Science.gov (United States)

    Łapsa, Joanna; Onderka, Bogusław

    2016-08-01

    The thermodynamic properties of liquid Ag-Sb-Sn alloys were obtained through use of the drop solution calorimetric method and electromotive force (emf) measurements of galvanic cells with a yttria stabilized zirconia (YSZ) solid electrolyte. The experiments were carried out along Ag0.25Sb0.75, Ag0.5Sb0.5 and Ag0.75Sb0.25 sections of the ternary system in the temperature range from 973 K to 1223 K. From the measured emf, the tin activity in liquid solutions of Ag-Sb-Sn was determined for the first time. The partial and integral enthalpy of mixing were determined from calorimetric measurements at two temperatures. These measurements were performed along two cross-sections: Sb0.5Sn0.5 at 912 K and 1075 K, and Ag0.75Sb0.25 at 1075 K. Both experimental data sets were used to find ternary interaction parameters by applying the Redlich-Kister-Muggianu model of the substitutional solution. Consequently, the set of parameters describing the thermodynamic properties of the liquid phase was derived.

  6. Magneto-elastic effects and thermodynamic properties of ferromagnetic hcp Co

    International Nuclear Information System (INIS)

    Using first principles projector augmented wave (PAW) potential method, the magneto-elastic effects and thermodynamic properties of ferromagnetic hcp Cobalt at high pressure and temperature are investigated. The calculated elastic constants from PBE+U method demonstrate a noticeable improvement with regard to experimental data. Various physical quantities under high pressure also present significant improvements, such as the bulk modulus, shear modulus, Young's modulus, Debye temperature, various sound velocities and the normalized acoustic velocities in the meridian plane. That is due to the fact that Cobalt system possesses large correlation effects. Meanwhile, the phonon dispersion curves are in excellent agreement with experimental data. It is not observed any anomaly or instability under compression. However, according to the E2g-phonon frequencies, the obtained pressure variation of C44 elastic modulus also suggests that the system has miraculous magneto-elastic effects. Moreover, the pressure and temperature dependence of thermodynamic properties are derived within the quasi-harmonic approximation for the first time. The obtained Grüneisen ratio, Anderon–Grüneisen parameter and the volume dependence of Grüneisen ratio display manifestly temperature and pressure dependences.

  7. The impact of the layer thickness on the thermodynamic properties of pd hydride thin film electrodes.

    Science.gov (United States)

    Vermeulen, Paul; Ledovskikh, Alexander; Danilov, Dmitry; Notten, Peter H L

    2006-10-19

    Recently, a lattice gas model was presented and successfully applied to simulate the absorption/desorption isotherms of various hydride-forming materials. The simulation results are expressed by parameters corresponding to several energy contributions, e.g., interaction energies. However, the use of a model system is indispensable in order to show the strength of the simulations. The palladium-hydrogen system is one of the most thoroughly described metal hydrides found in the literature and is therefore ideal for this purpose. The effects of decreasing the thickness of Pd thin films on the isotherms have been monitored experimentally and subsequently simulated. An excellent fit of the lattice gas model to the experimental data is found, and the corresponding parameters are used to describe several thermodynamic properties. It is analyzed that the contribution of H-H interaction energies to the total energy and the influence of the host lattice energy are significantly and systematically changing as a function of Pd thickness. Conclusively, it has been verified that the lattice gas model is a useful tool to analyze thermodynamic properties of hydrogen storage materials. PMID:17034217

  8. Hybrid density functional study on lattice vibration, thermodynamic properties, and chemical bonding of plutonium monocarbide

    Science.gov (United States)

    Rong, Yang; Bin, Tang; Tao, Gao; BingYun, Ao

    2016-06-01

    Hybrid density functional theory is employed to systematically investigate the structural, magnetic, vibrational, thermodynamic properties of plutonium monocarbide (PuC and PuC0.75). For comparison, the results obtained by DFT, DFT + U are also given. For PuC and PuC0.75, Fock-0.25 hybrid functional gives the best lattice constants and predicts the correct ground states of antiferromagnetic (AFM) structure. The calculated phonon spectra suggest that PuC and PuC0.75 are dynamically stable. Values of the Helmholtz free energy ΔF, internal energy ΔE, entropy S, and constant-volume specific heat C v of PuC and PuC0.75 are given. The results are in good agreement with available experimental or theoretical data. As for the chemical bonding nature, the difference charge densities, the partial densities of states and the Bader charge analysis suggest that the Pu–C bonds of PuC and PuC0.75 have a mixture of covalent character and ionic character. The effect of carbon vacancy on the chemical bonding is also discussed in detail. We expect that our study can provide some useful reference for further experimental research on the phonon density of states, thermodynamic properties of the plutonium monocarbide. Project supported by the National Natural Science Foundation of China (Grant Nos. 21371160 and 21401173).

  9. Elastic and thermodynamic properties of AuAl2 under pressures

    International Nuclear Information System (INIS)

    Highlights: ► Elastic constants of AuAl2 at ambient pressure are obtained successfully. ► The elastic moduli under pressure shows it is more difficult to compress with pressure. ► Stronger metallic character with pressure is obtained by Blackman's diagram. ► Thermodynamic properties are investigated in details. - Abstract: First-principles calculation results of the structural, elastic and thermodynamic properties of AuAl2 in the cubic fluorite structure at high pressures have been carried out using the pseudopotentials plane wave method within the local density approximation (LDA). The obtained lattice constant and bulk modulus at ambient conditions are in excellent agreement with the previous experimental and theoretical results. The calculated value of three independent elastic constants C11, C12, and C44 for the cubic fluorite structure AuAl2 at ambient pressure is 159.53 GPa, 98.53 GPa, and 55.53 GPa, respectively. The elastic constants, bulk modulus, shear modulus, Young's modulus, Poisson's ratio and the Debye temperature under pressures are also extensively obtained. Additionally, the characters of the bonding of this alloy at high pressure have been analyzed and we find that the stronger metallic character of the bonds with increasing pressures. The dependence of heat capacity, thermal expansion coefficient, and Grüneisen parameter on pressure is also obtained in details.

  10. Spin-Peierls instability and incommensurability in the XY model-Dynamical and thermodynamical properties

    International Nuclear Information System (INIS)

    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)

  11. DNS of transcritical turbulent boundary layers at supercritical pressures under abrupt variations in thermodynamic properties

    Science.gov (United States)

    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.

  12. Study of thermodynamics and electronics properties of hybrids of substituted Haucke compounds

    International Nuclear Information System (INIS)

    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 ANi5 (A=La, Y, Ca) and LaNi5-xMx 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)

  13. Preparation, characterization and thermodynamic properties of Zr-containing Cl-bearing layered double hydroxides (LDHs)

    International Nuclear Information System (INIS)

    Zr-containing layered double hydroxides (LDHs) with variable xZrsolid = Zr/(Zr + Al) mole fractions were synthesized by a co-precipitation method at ambient conditions. The chemical compositions of samples and corresponding aqueous solutions after syntheses were analyzed by ICP-OES, EDX (Mg, Al, Zr) and ion chromatography (Cl-). Results of PXRD technique demonstrated that solids with 0 ≤ x Zrsolid ≤ 0.5 show only X-ray reflexes typical for pure LDH compositions, while products of syntheses with xZrsolid > 0.5 display additional patterns attributed to brucite. ICP-OES and EDX techniques shown that in pure Zr-containing LDHs the Mg/(Al + Zr) ratio is reducing with increase of xZrsolid and the stoichiometry of brucite-like layers corresponds to [Mg3-2xAl1-xZrx]. This fact may indicate that the incorporation of 1 Zr-containing specie results in the removal of 1 Al- and 2 Mg-containing species from the pure Mg-Al-composition. Such mechanism may be confirmed by the observation that measured a0 = b0 distances are generally consistent with theoretical estimates obtained from [Mg3-2xAl1-xZrx]-stoichiometry. The presence of predominant Mg2+, Al(OH)4- and Zr(OH)5- complexes in aqueous solutions after syntheses was established in thermodynamic calculations by applying GEMS-Selektor v.3. code and, therefore, the reaction: Mg3Al1(OH)8Cl1 + Zr(OH)5- = Mg1Zr1(OH)5Cl1 + Al(OH)4- + 2Mg2+ + 4OH- can describe a mechanism of Zr-substitution. Estimates of the molar Gibbs free energies of Zr-containing LDHs with 0 ≤ = xZrsolid ≤ 0.5 show that the incorporation of Zr into the LDH increasing significantly their aqueous solubility. Thus, it is not possible to neglect that Zr can be partly localized as Zr(OH)5--ligands in the interlayer space of the LDH structure.

  14. Preparation, characterization and thermodynamic properties of Zr-containing Cl-bearing layered double hydroxides (LDHs)

    Energy Technology Data Exchange (ETDEWEB)

    Rozov, Konstantin; Curtius, Hilde; Bosbach, Dirk [Forschungszentrum Juelich GmbH (Germany). Inst. of Energy and Climate Research (IEK-6) Nuclear Waste Management and Reactor Safety

    2015-07-01

    Zr-containing layered double hydroxides (LDHs) with variable xZr{sub solid} = Zr/(Zr + Al) mole fractions were synthesized by a co-precipitation method at ambient conditions. The chemical compositions of samples and corresponding aqueous solutions after syntheses were analyzed by ICP-OES, EDX (Mg, Al, Zr) and ion chromatography (Cl{sup -}). Results of PXRD technique demonstrated that solids with 0 ≤ x Zr{sub solid} ≤ 0.5 show only X-ray reflexes typical for pure LDH compositions, while products of syntheses with xZr{sub solid} > 0.5 display additional patterns attributed to brucite. ICP-OES and EDX techniques shown that in pure Zr-containing LDHs the Mg/(Al + Zr) ratio is reducing with increase of xZr{sub solid} and the stoichiometry of brucite-like layers corresponds to [Mg{sub 3-2x}Al{sub 1-x}Zr{sub x}]. This fact may indicate that the incorporation of 1 Zr-containing specie results in the removal of 1 Al- and 2 Mg-containing species from the pure Mg-Al-composition. Such mechanism may be confirmed by the observation that measured a{sub 0} = b{sub 0} distances are generally consistent with theoretical estimates obtained from [Mg{sub 3-2x}Al{sub 1-x}Zr{sub x}]-stoichiometry. The presence of predominant Mg{sup 2+}, Al(OH){sub 4}{sup -} and Zr(OH){sub 5}{sup -} complexes in aqueous solutions after syntheses was established in thermodynamic calculations by applying GEMS-Selektor v.3. code and, therefore, the reaction: Mg{sub 3}Al{sub 1}(OH){sub 8}Cl{sub 1} + Zr(OH){sub 5}{sup -} = Mg{sub 1}Zr{sub 1}(OH){sub 5}Cl{sub 1} + Al(OH){sub 4}{sup -} + 2Mg{sup 2+} + 4OH{sup -} can describe a mechanism of Zr-substitution. Estimates of the molar Gibbs free energies of Zr-containing LDHs with 0 ≤ = xZr{sub solid} ≤ 0.5 show that the incorporation of Zr into the LDH increasing significantly their aqueous solubility. Thus, it is not possible to neglect that Zr can be partly localized as Zr(OH){sub 5}{sup -}-ligands in the interlayer space of the LDH structure.

  15. Limit diffusion coefficients and some aqueous ions of 5f and 4f elements, thermodynamic consequences for actinides

    International Nuclear Information System (INIS)

    The diffusion of the aqueous ions of Am3+, Cm3+, Cf3+, Es3+ and for comparison, Ce3+, Eu3+, Gd3+, Tm3+, Yb3+ was investigated in aqueous LiCl-HCl solutions (pH=2.5) at 25.000C by the open-ended capillary method. The diffusion coefficients obtained in the limit of zero ionic strength are used to estimate the hydrated radius of the considered elements and, consequently, the average number h of water molecules involved. A single S-shaped curve is obtained when this number h is plotted versus the cristallographic radius of the lanthanide (III) and actinide (III) cations. A similar change is assumed, for the inner sphere hydration number, from which values can be derived for actinides. From these results ΔHsub(hyd)sup(0) values have been calculated using a general analytical expression of the hydration enthalpie developped in this work. Finally, data of the sum of ionization potentials are proposed for the transuranium elements

  16. Theoretical Studies on the Thermodynamic Properties and Detonation Performances of Bicyclic Nitramines: TNAD Isomers

    Institute of Scientific and Technical Information of China (English)

    QIU Ling; XIAO He-Ming; GONG Xue-Dong; JU Xue-Hai

    2006-01-01

    Ab initio molecular orbital calculations have been performed at Hartree-Fock (HF), second-order Mōller-Plesset (MP2), and hybrid density functional theory (DFT) B3LYP levels with 6-31G** basis set to investigate the low sensitive explosive trans-1,4,5,8-tetranitro-1,4,5,8- tetraazadecalin (TNAD) and its seven bicyclic isomers. Their molecular geometries, electronic structures, thermodynamic properties, and detonation performances were predicted and compared. The relationships between structures and various properties were discussed in detail. The calculated results agree well with the available experimental data, and suggest that some compounds may be novel potential candidates of high energy density materials (HEDMs) with performances better than TNT (2,4,6-trinitrotoluene) and similar to RDX (1,3,5-trinitro-1,3,5-triazacyclohexane).

  17. Thermodynamic simulation of the elastic and thermal properties of cobalt monosilicide

    Science.gov (United States)

    Povzner, A. A.; Filanovich, A. N.; Nogovitsyna, T. A.

    2016-06-01

    A self-consistent thermodynamic model is used to calculate the temperature dependences of the heat capacity, the thermal expansion coefficient, the bulk compression modulus, the density, Debye temperature, and the Grüneisen parameter of CoSi in the temperature range 0-1400 K. The calculation results agree well with the existing experimental data and can be used to predict the properties of CoSi in the temperature range that has not been experimentally studied. Cobalt monosilicide is shown to have a significant phonon anharmonicity, which can be caused by an electron-phonon interaction, and this anharmonicity should be taken into account in the simulation of its thermoelectric properties.

  18. Thermodynamic and Transport Properties of H2O + NaCl from Polarizable Force Fields.

    Science.gov (United States)

    Jiang, Hao; Mester, Zoltan; Moultos, Othonas A; Economou, Ioannis G; Panagiotopoulos, Athanassios Z

    2015-08-11

    Molecular dynamics and Monte Carlo simulations were performed to obtain thermodynamic and transport properties of the binary H2O + NaCl system using the polarizable force fields of Kiss and Baranyai ( J. Chem. Phys. 2013 , 138 , 204507 and 2014 , 141 , 114501 ). In particular, liquid densities, electrolyte and crystal chemical potentials of NaCl, salt solubilities, mean ionic activity coefficients, vapor pressures, vapor-liquid interfacial tensions, and viscosities were obtained as functions of temperature, pressure, and salt concentration. We compared the performance of the polarizable force fields against fixed-point-charge (nonpolarizable) models. Most of the properties of interest are better represented by the polarizable models, which also remain physically realistic at elevated temperatures. PMID:26574461

  19. Magnetic refrigeration cycle analysis using selected thermodynamic property characterizations for gadolinium gallium garnet

    International Nuclear Information System (INIS)

    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

  20. Electronic, thermodynamic and elastic properties of pyrite RuO_2

    Institute of Scientific and Technical Information of China (English)

    Yang Ze-Jin; Guo Yun-Dong; Wang Guang-Chang; Li Jin; Dai Wei; Liu Jin-Chao; Cheng Xin-Lu; Yang Xiang-Dong

    2009-01-01

    This paper calculates the elastic, thermodynamic and electronic properties of pyrite (Pa3) RuO_2 by the plane-wave pseudopotential density functional theory (DFT) method. The lattice parameters, normalized elastic constants, Cauchy pressure, brittle-ductile relations, heat capacity and Debye temperature are successfully obtained. The Murnaghan equation of state shows that pyrite RuO_2 is a potential superhard material. Internal coordinate parameter increases with pressure, which disagrees with experimental data. An analysis based on electronic structure and the pseudogap reveals that the bonding nature in RuO_2 is a combination of covalent, ionic and metallic bonding. A study of the elastic properties indicates that the pyrite phase is isotropic under usual conditions. The relationship between brittleness and ductility shows that pyrite RuO_2 behaves in a ductile matter at zero pressure and the degree of ductility increases with pressure.

  1. Structural, elastic and thermodynamic properties of Mo3Si and Mo3Ge

    Science.gov (United States)

    Zhong, Sheng-Yi; Chen, Zhe; Wang, Mingliang; Chen, Dong

    2016-01-01

    The structural, elastic and thermodynamic properties of the cubic Mo3Si and Mo3Ge intermetallics were investigated using density functional theory within the local density approximation (LDA) and generalized gradient approximation (GGA) methods. The results showed that the structural and elastic properties (i.e., elastic constants, bulk modulus, shear modulus and Young's modulus) derived by the GGA method were in good agreement with the available experimental and theoretical values. Using the quasi-harmonic Debye model, the variations of the Debye temperature, heat capacity and coefficient of thermal expansion under pressure ranging from 0 to 25 GPa and at temperature ranging from 0 to 1800 K were obtained and analyzed for both compounds.

  2. QSPR models based on molecular mechanics and quantum chemical calculations. 2. Thermodynamic properties of alkanes, alcohols, polyols, and ethers

    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 in...

  3. Rheological Properties of Aqueous Suspensions of Chitin Crystallites

    Science.gov (United States)

    Li; Revol; Marchessault

    1996-11-10

    Rheologically, suspensions of chitin crystallites are found to behave as other molecular liquid crystalline polymers (LCPs). The average hydrodynamic diameter of the crystallites in the suspension at pH 4 is determined to be approximately 80 nm using dynamic light scattering. Conductimetric and pH titration results show that the pKa of the crystallites is 6.3, which is the same as that reported for chitosan. In combination with phase diagrams, flow properties of isotropic, biphasic, and anisotropic chitin suspensions were investigated. For isotropic suspensions, a classical shear thinning behavior of rodlike particles is observed. In the case of biphasic suspensions, a two-regime curve is observed where tactoids first orient, deform, and then break up under a shearing force. Similar to other LCPs, a three-regime flow curve is found for the anisotropic suspensions. The viscosity-concentration curve exhibits a maximum at the phase separation concentration, and this maximum is less distinct with a decrease of the ionic strength. Secondary electroviscous effects due to strong particle-particle interactions influence the viscosity of the suspensions at higher concentrations. PMID:8954679

  4. Correlation of Thermodynamic Properties and Atomic Transport in the Uranium Dioxide Phase

    International Nuclear Information System (INIS)

    The correlations of thermodynamic properties with atomic transport, if they are to be meaningfully simultaneous considerations rather than suggestive by tabulations, must be based on a framework which is quantitative and circumspective. A model within this framework for the uranium dioxide phase is presented as a guide for studies relating basic (atomic) properties to the practical problems encountered in oxidation, sintering, phase separation, fission gas release, etc. To attempt to clarify some of the confusion resulting from investigations of correlated properties of a system as complex as uranium dioxide, special attention must be devoted to a perspective which recognizes local thermodynamic equilibrium vis à vis non-equilibrium. This permits a comprehensive description which includes both self-diffusion and chemical diffusion and which indicates that processes such as sintering can be controlled by the more rapidly diffusing species rather than by the slower one. The local thermodynamic equilibrium theory of self-diffusion by Rice et al. when combined with the defect theory of non-stoichiometiy, yields for the self-diffusion coefficient D = Z/4 2 > v { x + [ x2 + (8qi)/(qv)exp (-(Ev - Ei)/RT)]½} exp (-Uℓ/RT) in which Z is the number of nearest neighbours, 2> is the mean square of the diffusional jump, v is the mean vibrational frequency of the lattice, and Uℓ is an energy composed of energies associated with the correlation of the diffusing species vibrating out of phase with its shell of neighbours. All these quantities are related to the lattice dynamics and thus to the macroscopic properties such as specific heat and elastic modulus. The quantity in the curly brackets is derived from the defect theory of non-stoichiometry which permits the incorporation of the compositional variable x, the vibrational partition functions associated with interstitial and vacant sites, qi and qv, and the energies required to produce vacancies Ev and to remove atoms from

  5. Thermodynamic properties of lanthanum and lanthanide halides: Communication III. Thermodynamic functions of LnF2 (gas)

    International Nuclear Information System (INIS)

    The molecular constants of LnF2 (Ln = La-Lu) have been estimated based on the available spectroscopic characteristics of lanthanum and lanthanide difluorides. These constants have been used for calculating the reduced Gibbs energy -[G0(T) - H0(0)]/T of the compounds in the ideal gas state in the range 298.15-3000 K at the standard pressure p0 = 0.1 MPa. The electronic contribution to thermodynamic functions has been calculated taking into account the excitation energies of low-lying (-1) electronic states of Ln2+ ions. The splitting of the ground state term of Ln2+ in the ligand field is estimated

  6. Temperature, pressure, and electrochemical constraints on protein speciation: Group additivity calculation of the standard molal thermodynamic properties of ionized unfolded proteins

    Directory of Open Access Journals (Sweden)

    J. M. Dick

    2006-01-01

    Full Text Available Thermodynamic calculations can be used to quantify environmental constraints on the speciation of proteins, such as the pH and temperature dependence of ionization state, and the relative chemical stabilities of proteins in different biogeochemical settings. These calculations depend in part on values of the standard molal Gibbs energies of proteins and their ionization reactions as a function of temperature and pressure. Because these values are not generally available, we calculated values of the standard molal thermodynamic properties at 25°C and 1 bar as well as the revised Helgeson-Kirkham-Flowers equations of state parameters of neutral and charged zwitterionic reference model compounds including aqueous amino acids, polypeptides, and unfolded proteins. The experimental calorimetric and volumetric data for these species taken from the literature were combined with group additivity algorithms to calculate the properties and parameters of neutral and ionized sidechain and backbone groups in unfolded proteins. The resulting set of group contributions enables the calculation of the standard molal Gibbs energy, enthalpy, entropy, isobaric heat capacity, volume, and isothermal compressibility of unfolded proteins in a range of proton ionization states to temperatures and pressures exceeding 100°C and 1000 bar. This approach provides a useful frame of reference for thermodynamic studies of protein folding and complexation reactions. It can also be used to assign provisional values of the net charge and Gibbs energy of ionized proteins as a function of temperature and pH. Using these values, an Eh-pH diagram for a reaction representing the speciation of extracellular proteins from Pyrococcus furiosus and Bacillus subtilis was generated. The predicted predominance limits of these proteins correspond with the different electrochemical conditions of hydrothermal vents and soils. More comprehensive calculations of this kind may reveal pervasive

  7. The properties and transport phenomena in oxide films on iron, nickel, chromium and their alloys in aqueous environments

    Energy Technology Data Exchange (ETDEWEB)

    Laitinen, T.; Bojinov, M.; Betova, I.; Maekelae, K.; Saario, T. [VTT Manufacturing Technology, Espoo (Finland)

    1999-01-01

    . In addition, the films are to a large extent influenced by the kinetic factors determining their growth rate and steady state thickness. Thus a thermodynamic consideration of the film is not sufficient to model and predict its growth and dissolution. Instead, kinetic models based on in situ experimental data are required. The kinetic models presented in the literature for both ambient and high-temperature aqueous oxidation of metals lack a correlation between the structure of the oxide films and their electronic and ionic properties. Also, a quantitative treatment and thus the capability to predict material behaviour in varying conditions is lacking. A comprehensive understanding of the correlation between applied water chemistry, the behaviour of oxide films and optimum performance of the plant is thus also lacking. The situation calls for more experimental work combined with comprehensive modelling of the behaviour of both the compact and the porous part of the oxide film formed on a metal surface. This will make it possible to recognise the rate-limiting steps of the processes in the film, and thus to influence the rate of activity incorporation and different corrosion phenomena related to transport of species in the film. (author) 210 refs.

  8. The properties and transport phenomena in oxide films on iron, nickel, chromium and their alloys in aqueous environments

    International Nuclear Information System (INIS)

    . In addition, the films are to a large extent influenced by the kinetic factors determining their growth rate and steady state thickness. Thus a thermodynamic consideration of the film is not sufficient to model and predict its growth and dissolution. Instead, kinetic models based on in situ experimental data are required. The kinetic models presented in the literature for both ambient and high-temperature aqueous oxidation of metals lack a correlation between the structure of the oxide films and their electronic and ionic properties. Also, a quantitative treatment and thus the capability to predict material behaviour in varying conditions is lacking. A comprehensive understanding of the correlation between applied water chemistry, the behaviour of oxide films and optimum performance of the plant is thus also lacking. The situation calls for more experimental work combined with comprehensive modelling of the behaviour of both the compact and the porous part of the oxide film formed on a metal surface. This will make it possible to recognise the rate-limiting steps of the processes in the film, and thus to influence the rate of activity incorporation and different corrosion phenomena related to transport of species in the film. (author)

  9. Liquid-liquid equilibrium of water + PEG 8000 + magnesium sulfate or sodium sulfate aqueous two-phase systems at 35°C: experimental determination and thermodynamic modeling

    Directory of Open Access Journals (Sweden)

    B. D. Castro

    2005-09-01

    Full Text Available Liquid-liquid extraction using aqueous two-phase systems is a highly efficient technique for separation and purification of biomolecules due to the mild properties of both liquid phases. Reliable data on the phase behavior of these systems are essential for the design and operation of new separation processes; several authors reported phase diagrams for polymer-polymer systems, but data on polymer-salt systems are still relatively scarce. In this work, experimental liquid-liquid equilibrium data on water + polyethylene glycol 8000 + magnesium sulfate and water + polyethylene glycol 8000 + sodium sulfate aqueous two-phase systems were obtained at 35°C. Both equilibrium phases were analyzed by lyophilization and ashing. Experimental results were correlated with a mass-fraction-based NRTL activity coefficient model. New interaction parameters were estimated with the Simplex method. The mean deviations between the experimental and calculated compositions in both equilibrium phases is about 2%.

  10. A comprehensive guide to experimental and predicted thermodynamic properties of phosphate apatite minerals in view of applicative purposes

    International Nuclear Information System (INIS)

    Graphical abstract: Experimental thermodynamic properties of phosphate apatites are reviewed and commented. Predictive methods are developed and tested here for apatite compounds, allowing reliable estimations of ΔHf°, ΔGf° and S°, not only for end-members but also for solid solutions, non-stoichiometric and hydrated samples. A periodic table of recommended thermodynamic properties for 33 apatite systems is generated, and relative stabilities are pointed out. - Highlights: • Experimental thermodynamic properties of phosphate apatites are reviewed. • Predictive thermodynamic methods are investigated for estimating missing data. • An additive model is developed to estimate ΔHf°, ΔGf° and S° for phosphate apatites. • End-members, solid solutions, nonstoichiometric and hydrated samples are considered. • A periodic table of recommended thermodynamic properties for 33 systems is proposed. - Abstract: Apatite minerals represent a major class of ionic compounds of interest to many disciplines including medical sciences, geology, anthropology, cosmology, environmental and nuclear sciences. Yet, these compounds have not received great attention from a thermodynamic viewpoint, and some diverging data – often drawn from molecular modeling assays – were reported. In this contribution, an extensive literature overview of available experimental-based data on M10(PO4)6X2 apatites with M = Ca, Ba, Sr, Mg, Cd, Pb, Cu, Zn and X = OH, F, Cl or Br has first been made, on the basis of standard formation energetics (ΔHf° and ΔGf°) as well as entropy S° and molar heat capacity Cp,m°. The case of oxyapatite was also included. From this overview, it was then possible to identify general tendencies, evidencing in particular the primary role of electronegativity and secondarily of ionic size. Using the experimental data as reference, several predictive thermodynamic methods were then evaluated, including the volume-based-thermodynamics (VBT) method and a more

  11. THERMODYNAMIC STUDY ON ADSORPTION OF AROMATIC SULFONIC ACIDS ONTO MACROPOROUS WEAK BASE ANION EXCHANGER FROM AQUEOUS SOLUTIONS

    Institute of Scientific and Technical Information of China (English)

    Chao Long; Quan-xing Zhang; Ai-min Li; Jin-long Chen

    2004-01-01

    The adsorption equilibrium isotherms of three aromatic sulfonic acid compounds, 2-naphthalenesulfonic acid, ptoluenesulfonic acid and p-chlorobenzenesulfonic acid, from aqueous solutions by macroporous weak base anion exchanger within the temperature range of 293 K-313 K were obtained. Several isotherm equations were correlated with the equilibrium data, and the experimental data was found to fit the three-parameter Redlich-Peterson equation best within the entire range of concentrations. The study showed that the hydrophobicity of solute has distinct influence on adsorption capacity of the anion exchanger for the aromatic sulfonic acid. Moreover, estimations of the isosteric enthalpy, free energy,and entropy change of adsorption were also reported. The positive isosteric enthalpy and entropy change for adsorption indicate an endothermic and entropy driven process in the present study.

  12. Thermodynamic and optical studies of some ethylene glycol ethers in aqueous solutions at T = 298.15 K

    International Nuclear Information System (INIS)

    Experimental results of density (ρ), speed of sound (u), and refractive index (nD) have been obtained for aqueous solutions of ethylene glycol monomethyl ether (EGMME), ethylene glycol monoethyl ether (EGMEE), diethylene glycol monomethyl ether (DEGMME), and diethylene glycol monoethyl ether (DEGMEE) over the entire concentration range at T = 298.15 K. From these measurements, the derived parameters, apparent molar volume of solute (φV), excess molar volume (VE), isentropic compressibility of solution (βS), apparent molar isentropic compressibility of solute (φKS), deviation in isentropic compressibility (ΔβS), molar refraction [R]1,2 and deviation in refractive index of solution (ΔnD) have been calculated. The Redlich-Kister equation has been fitted to the calculated values of VE, ΔβS and ΔnD for the solution. The results obtained are interpreted in terms of hydrogen bonding and various interactions among solute and solvent molecules

  13. Fabrication of uranium-americium mixed oxide fuels: thermodynamical modeling and materials properties

    International Nuclear Information System (INIS)

    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 U1-yAmyO2+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, U1-yAmyO2+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)

  14. Oxidation-reduction properties of americium, curium, berkelium, californium, einsteinium and fermium, and thermodynamic consequences for the 5f series

    International Nuclear Information System (INIS)

    The amalgamation of 5f elements from Am to Fm has been studied by using 241Am, 244Cm, 249Bk, 249Cf, 252Cf, 253Es, 254Es, 252Fm and 255Fm with two electrochemical methods, radiocoulometry and radiopolarography, perfectly adapted to investigate extremely diluted solutions when the concentration of electroactive species is as low as 10-16M. The theory of radiocoulometry has been developed in the general cases of reversible and irreversible electrode process. It has been used to interpret the experimental data on the kinetic curves of amalgamation, and to estimate the standard rate constant of the electrode process in complexing medium (citric). On the other hand the radiopolarographic method has been applied to study the mechanism of reduction at the dropping mercury electrode of cations M3+ in aqueous medium to the metal M with formation of amalgam. The results are exploited into two directions: 1- Acquisition of some data concerning the oxidation-reduction properties of elements from Am to Fm. Therefore the standard electrode E0 [M(III-0)] potentials for Bk, Cf and Es, and the standard electrode E0 [M(II-0)] potential for Fm are estimated and the relative stability of each oxidation state (from II to VII) of 5f elements is discussed; 2- Acquisition of unknown thermodynamic data on transcalifornium elements. Correlations between 4f and 5f elements are precised and some divergences appear for the second half of 4f and 5f series (i.e. for 65<=Z<=71 and 97<=Z<=103)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1987-04-01

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

  16. Reference Publications Being Prepared in the Soviet Union on the Thermodynamic Properties of Substances

    International Nuclear Information System (INIS)

    In 1956 and 1962 two editions of the handbook ''Thermodynamic properties of substances'' were published in the Soviet Union. The second edition of this book gave data on the properties of 335 substances over a wide temperature range. At the present time supplements to the book are being prepared dealing with the properties of several hundred more substances and, on the basis of new studies and calculations, giving more precise details on the properties of the substances included in the previous editions. The first supplement, which will be published in 1965, will contain data on a number of transition metals (Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W) and their oxides. The following supplement will deal with compounds of alkali metals. A handbook entitled ''Thermal constants of substances'' is also being prepared giving heats and free energies of formation, dissociation energies, entropies and other properties at 0 and 298.15°K; phase transition temperatures and heats and critical parameters for all the inorganic and the simplest organic substances studied are also given. The first parts of this book will appear in 1965, dealing with oxygen, hydrogen and its isotopes, halogens, noble gases, elements of the sulphur and nitrogen groups, and compounds formed between these elements. The two handbooks represent a co-ordinated system of critically selected quantities. (author)

  17. Thermodynamic, morphological and structural properties of dissociated fatty acid monolayers at the air-water interface

    Science.gov (United States)

    Johann, Robert

    2001-10-01

    Research on monolayers of amphiphilic lipids on aqueous solution is of basic importance in surface science. Due to the applicability of a variety of surface sensitive techniques, floating insoluble monolayers are very suitable model systems for the study of order, structure formation and material transport in two dimensions or the interactions of molecules at the interface with ions or molecules in the bulk (headword 'molecular recognition'). From the behavior of monolayers conclusions can be drawn on the properties of lipid layers on solid substrates or in biological membranes. This work deals with specific and fundamental interactions in monolayers both on the molecular and on the microscopic scale and with their relation to the lattice structure, morphology and thermodynamic behavior of monolayers at the air-water interface. As model system especially monolayers of long chain fatty acids are used, since there the molecular interactions can be gradually adjusted by varying the degree of dissociation by means of the suphase pH value. For manipulating the molecular interactions besides the subphase composition also temperature and monolayer composition are systematically varied. The change in the monolayer properties as a function of an external parameter is analyzed by means of isotherm and surface potential measurements, Brewster-angle microscopy, X-ray diffraction at grazing incidence and polarization modulated infrared reflection absorption spectroscopy. For this a quantitative measure for the molecular interactions and for the chain conformational order is derived from the X-ray data. The most interesting results of this work are the elucidation of the origin of regular polygonal and dendritic domain shapes, the various effects of cholesterol on molecular packing and lattice order of long chain amphiphiles, as well as the detection of an abrupt change in the head group bonding interactions, the chain conformational order and the phase transition pressure

  18. Comparison of physicomechanical properties of films prepared from organic solutions and aqueous dispersion of Eudragit RL

    Directory of Open Access Journals (Sweden)

    H Afrasiabi Garekani

    2011-05-01

    Full Text Available Background and the purpose of the study: Mechanical properties of films prepared from aqueous dispersion and organic solutions of Eudragit RL were assessed and the effects of plasticizer type, concentration and curing were examined. Methods: Films were prepared from aqueous dispersion and solutions of Eudragit RL (isopropyl alcohol-water 9:1 containing 0, 10 or 20% (based on polymer weight of PEG 400 or Triethyl Citrate (TEC as plasticizer using casting method. Samples of films were stored in oven at 60ºC for 24 hrs (Cured. The stress-strain curve was obtained for each film using material testing machine and tensile strength, elastic modulus, %elongation and work of failure were calculated. Results and major conclusion: The films with no plasticizer showed different mechanical properties depending on the vehicle used. Addition of 10% or 20% of plasticizer decreased the tensile strength and elastic modulus and increased %elongation and work of failure for all films. The effect of PEG400 on mechanical properties of Eudragit RL films was more pronounced. The differences in mechanical properties of the films due to vehicle decreased by addition of plasticizer and increase in its concentration. Curing process weakened the mechanical properties of the films with no plasticizer and for films with 10% plasticizer no considerable difference in mechanical properties was observed before and after curing. For those with 20% plasticizer only films prepared from aqueous dispersion showed remarkable difference in mechanical properties before and after curing. Results of this study suggest that the mechanical properties of the Eudragit RL films were affected by the vehicle, type of plasticizer and its concentration in the coating liquid.

  19. Theoretical Insight of Physical Adsorption for a Single-Component Adsorbent + Adsorbate System: I. Thermodynamic Property Surfaces

    KAUST Repository

    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.

  20. Chitosan metal-crosslinked beads applied for n-alkylmonoamines removal from aqueous solutions – a thermodynamic study

    International Nuclear Information System (INIS)

    Highlights: • Chitosan beads were successfully synthesized with divalent cations. • Well-formed bead structures containing cations act as acceptor electron sites. • n-Alkylmonoamine/bead interactions are favorably sorbed at the solid/liquid interface. • The thermodynamic data were favorably obtained from calorimetric titrations. • Crosslinked metal–chitosan beads can remove amine-like substances from an ecosystem. - Abstract: Chitosan has ability in coordinating divalent cations when immersed in crosslinked beads, after dripping: (i) chitosan gel into a copper solution, (ii) nickel chitosan gel into sodium hydroxide and (iii) chitosan/cobalt gel into sodium tripolyphosphate. The amounts of (1.82; 1.27 and 0.44) mmol · g−1 for copper, nickel and cobalt cations in these well-formed structures were determined, to give nitrogen/metal ratios of 3.52; 2.09 and 8.51, indicating the least effectiveness for cobalt in the coordination. Copper cation is well-adjusted in the coordination model through free amino and hydroxyl electron pairs, while amino and acetamino groups for nickel and cobalt were used. The chitosan–hydrogen bond breaking in bead formation caused decreases in crystallinity to yield amorphous structures for cobalt and nickel. The water mass fraction released during heating depends on the hydration of the cations, with the highest value of 0.20 for cobalt. The quantitative aspects of the interaction among cations on beads and basic n-alkylmonoamines determined via sorption batch methodology adjusted to the Langmuir isothermal model, with maximum sorption quantities to saturate nickel of (2.50; 2.38; 2.03; 1.79) mmol · g−1 and copper of (2.59; 2.29; 2.28; 1.92) mmol · g−1 for ethyl- propyl-, butyl- and pentylamines, respectively. The interaction energies quantitatively determined from isothermal titration calorimetry (ITC) at the solid/liquid interface resulted in exothermic enthalpic values. These negative enthalpy values combined to the

  1. Kinetic, Equilibrium and thermodynamic studies on the biosorption of Cd(II) from aqueous solutions by the leaf biomass of Calotropis procera - 'Sodom apple'

    Science.gov (United States)

    Chukwudumebi Overah, Loretta; Babalola, Oyebamiji.; Babarinde, Adesola; Oninla, Vincent; Olatunde, Abimbola

    2013-04-01

    The kinetics, equilibrium and thermodynamics of the biosorption of Cd (II) from aqueous solution by the leaf biomass of Calotropis procera popularly known in western Nigeria as 'bom bom' and generally known as Sodom apple were investigated at different experimental conditions. Optimum conditions of pH,contact time, biomass dosage, initial metal ion concentration and temperature were determined to be 5, 60 minutes, 110 mg, 0.3 mM and 27°C respectively. The maximum biosorption capacity was found to be 8.91 mg/g. The kinetic studies indicated that the biosorption process of the metal ion followed the pseudo-second-order and intra-particle diffusion models with an R-square value of 0.998 and 0.985 respectively. Equilibrium studies showed that the biosorption of Cd (II) is well represented by both Freundlich and Langmuir isotherms but the Langmuir model gave a better fit with an R-square value of 0.979,Langmuir constant, bm of 0.0080 and monolayer adsorption capacity, μm of 123.46. The calculated thermodynamic parameters (ΔG° -4.846 kJmol-1, ΔH° 10.60 kJmol-1 and ΔS° 0.052 kJK-1mol-1) showed that the biosorption of Cd (II)is feasible, spontaneous, endothermic and highly disordered in nature under the experimental conditions. Thesefindings indicate that the leaf of Calotropis procera could be employed in the removal of Cd (II) from industrial effluents. Key words: Calotropis procera, Cadmium, Adsorption isotherm.

  2. Kinetics and Thermodynamics of Cd(II Ions Sorption on Mixed Sorbents Prepared from Olive Stone and Date Pit from Aqueous Solution

    Directory of Open Access Journals (Sweden)

    N. Babakhouya

    2010-01-01

    Full Text Available Problem statement: The aim of this study is to remove Cd(II ions from aqueous solutions by adsorption. Mixed sorbent prepared from olive stone and date pit, an agricultural solid by-product was used as adsorbent. Approach: The adsorption experiments of Cd(II onto the mixture of olive stone and date pit were conducted at different parameters such as, percent of olive stone and date pit in the mixture, temperature, initial solution pH and initial Cd(II concentration. Adsorption isotherms were obtained at different percent of olive stone and date pit in the mixture. Results: This adsorption data was fitted with the Langmuir. Kinetic studies revealed that the initial uptake was rapid and equilibrium was established in 20 min for all the studied metals and that the data followed the pseudo-second order reaction. The thermodynamic of Cadmium sorption on the mixed sorbent follows the Langmuir model and the sorption capacity for cadmium increases when we add a small amount of olive stone at date pits (90% of date pits in mixture and 10% of olive stone and a small amount of date pits at olive stone (90% of olive stone and 10% of date pits in mixture. In addition, the thermodynamic parameters, standard free energy (ÄG°, standard enthalpy (ÄH° and standard entropy (ÄS° of the adsorption process were calculated. The sorption of Cd(II onto the mixture of olive stones and dates pit is spontaneous and presents an endothermic nature. The characteristics of the mixture were determined by the analysis of infra red spectral analysis. Conclusion: The results show that the mixture sorbent from olive stone and date pit is an alternative low-cost adsorbent for removing Cd(II.

  3. Kinetic, equilibrium and thermodynamic studies on sorption of uranium and thorium from aqueous solutions by a selective impregnated resin containing carminic acid

    International Nuclear Information System (INIS)

    Highlights: • The objective of the study is to investigate the potential application of a selective EIR for sorption of U(VI) and Th(IV) ions. • The effects of several physiochemical parameters were investigated. • The sorption kinetics and sorption isotherms were used to explain the sorption mechanism. • The thermodynamic studies showed the feasibility of sorption process. • The EIR beads showed a great potential for effective removal of U(VI) and Th(IV) ions. - Abstract: In this work, the removal of uranium and thorium ions from aqueous solutions was studied by solid–liquid extraction using an advantageous extractant-impregnated resin (EIR) prepared by loading carminic acid (CA) onto Amberlite XAD-16 resin beads. Batch sorption experiments using CA/XAD-16 beads for the removal of U(VI) and Th(IV) ions were carried out as a function of several parameters, like equilibration time, metal ion concentration, etc. The equilibrium data obtained from the sorption experiments were adjusted to the Langmuir isotherm model and the calculated maximum sorption capacities in terms of monolayer sorption were in agreement with those obtained from the experiments. The experimental data on the sorption behavior of both metal ions onto the EIR beads fitted well in both Bangham and intra-particle diffusion kinetic models, indicating that the intra-particle diffusion is the rate-controlling step. The thermodynamic studies at different temperatures revealed the feasibility and the spontaneous nature of the sorption process for both uranium and thorium ions

  4. Kinetic, equilibrium and thermodynamic studies on sorption of uranium and thorium from aqueous solutions by a selective impregnated resin containing carminic acid

    Energy Technology Data Exchange (ETDEWEB)

    Rahmani-Sani, Abolfazl [Wastewater Division, Faculty of Health, Sabzevar University of Medical Sciences, PO Box 319, Sabzevar (Iran, Islamic Republic of); Hosseini-Bandegharaei, Ahmad, E-mail: ahoseinib@yahoo.com [Wastewater Division, Faculty of Health, Sabzevar University of Medical Sciences, PO Box 319, Sabzevar (Iran, Islamic Republic of); Department of Engineering, Kashmar Branch, Islamic Azad University, PO Box 161, Kashmar (Iran, Islamic Republic of); Hosseini, Seyyed-Hossein [Department of Engineering, Kashmar Branch, Islamic Azad University, PO Box 161, Kashmar (Iran, Islamic Republic of); Kharghani, Keivan [Water Division, Department of Engineering, Torbat-e-Hydarieh Branch, Islamic Azad University, PO Box 121, Torbat-e-Hydarieh (Iran, Islamic Republic of); Zarei, Hossein [Department of Engineering, Kashmar Branch, Islamic Azad University, PO Box 161, Kashmar (Iran, Islamic Republic of); Rastegar, Ayoob [Wastewater Division, Faculty of Health, Sabzevar University of Medical Sciences, PO Box 319, Sabzevar (Iran, Islamic Republic of); Department of Engineering, Kashmar Branch, Islamic Azad University, PO Box 161, Kashmar (Iran, Islamic Republic of)

    2015-04-09

    Highlights: • The objective of the study is to investigate the potential application of a selective EIR for sorption of U(VI) and Th(IV) ions. • The effects of several physiochemical parameters were investigated. • The sorption kinetics and sorption isotherms were used to explain the sorption mechanism. • The thermodynamic studies showed the feasibility of sorption process. • The EIR beads showed a great potential for effective removal of U(VI) and Th(IV) ions. - Abstract: In this work, the removal of uranium and thorium ions from aqueous solutions was studied by solid–liquid extraction using an advantageous extractant-impregnated resin (EIR) prepared by loading carminic acid (CA) onto Amberlite XAD-16 resin beads. Batch sorption experiments using CA/XAD-16 beads for the removal of U(VI) and Th(IV) ions were carried out as a function of several parameters, like equilibration time, metal ion concentration, etc. The equilibrium data obtained from the sorption experiments were adjusted to the Langmuir isotherm model and the calculated maximum sorption capacities in terms of monolayer sorption were in agreement with those obtained from the experiments. The experimental data on the sorption behavior of both metal ions onto the EIR beads fitted well in both Bangham and intra-particle diffusion kinetic models, indicating that the intra-particle diffusion is the rate-controlling step. The thermodynamic studies at different temperatures revealed the feasibility and the spontaneous nature of the sorption process for both uranium and thorium ions.

  5. Electronic structures, mechanical and thermodynamic properties of cubic alkaline-earth hexaborides from first principles calculations

    International Nuclear Information System (INIS)

    Highlights: • The band gaps for CaB6, SrB6 and BaB6 depend sensitively on the values of lattice constant a and positional parameter z. • The order in elastic anisotropy is CaB6 > SrB6 > BaB6. • There are LO/TO splitting lines in the range of 5–10 THz at G point. - Abstract: The electronic structures, mechanical and thermodynamic properties of alkaline-earth hexaborides MB6 (M = Ca, Sr or Ba) are calculated from first principles using density functional theory combined with the quasi-harmonic approximation. These three alkaline-earth hexaborides are semiconductors with a slightly increased trend for their band gaps as M orders from Ca to Ba. Their band gaps depend sensitively on the values of lattice constant a and internal parameter z. The polycrystalline values of the elastic constants and bulk, shear and Young’s moduli are consistent with those determined experimentally. All alkaline-earth hexaborides have strongly anisotropic elastic properties in the order of CaB6 > SrB6 > BaB6. By using the phonon calculations, the thermodynamic properties are investigated. The obtained phonon dispersion relations for CaB6, SrB6, and BaB6 show similar features and there are LO/TO splitting lines in the range of 5–10 THz. Finally, the thermal conductivities of CaB6, SrB6 and BaB6 are evaluated via Clarke’s model and Cahill’s model

  6. Study of thermodynamic properties of Pu-Al alloys in eutectic LiCl-KCl

    International Nuclear Information System (INIS)

    Pyrochemical separation processes are considered as a promising alternative to the hydrometallurgical methods. A technique developed in ITU is based on electrochemical reduction of actinides on an Al cathode in molten salts. This work is focused on chemical characterisation and determination of thermodynamic properties of Pu-Al alloys. The alloys are formed on a solid Al electrode during Pu electrodeposition in molten LiCl-KCl Eutectic. A carbo-chlorination was applied to convert PuO2 added to the molten salt in order to produce a LiCl-KCl-PuCl3 (∼2 wt.%). It was proven, by electrochemical measurements, that the salt contained pure PuCl3 without impurities. Pu-Al alloy properties were studied in the temperature range of 400 - 550 deg. C by electrochemical techniques. Cyclic voltammetry showed one reduction step of Pu3+ on inert W electrode (Pu3+/Pu0). On reactive aluminium electrode, reduction of Pu3+ to Pu0 occurs at more positive potential due to the formation of Pu-Al intermetallic compounds. Open Circuit Potentiometric (OCP) measurements, after depositions of Pu metal onto the Al electrode by short galvanic electrolysis, were used to identify Pu-Al intermetallic compounds. The curves obtained after OCP measurements exhibits 6 plateaus which is in agreement with the Pu-Al phase diagram, containing 5 compounds stable at working temperature range. The thermodynamic properties of the Pu-Al alloys (ΔG, ΔH, ΔS) were deduced from those curves by e.m.f. measurements. Pu-Al deposits were obtained by galvano-static electrolyses on Al plates. XRD and SEM analysis revealed a mixture of PuAl3 and PuAl4 alloys. (authors)

  7. A DFT study to unravel the ligand exchange kinetics and thermodynamics of Os(VIII) oxo/hydroxido/aqua complexes in aqueous matrices.

    Science.gov (United States)

    van Niekerk, Daniel M E; Gerber, Wilhelmus J; Koch, Klaus R

    2016-04-19

    The Os(VIII) oxo/hydroxido complexes that are abundant in mild to relatively concentrated basic aqueous solutions are Os(VIII)O4, [Os(VIII)O4(OH)](-) and two cis-[Os(VIII)O4(OH)2](2-) species. Os(VIII) complexes that contain water ligands are thermodynamically unfavoured w.r.t. the abovementioned species. Os(VIII)O4 reacts with hydroxide in two, consecutive, elementary coordination sphere expansion steps to form the [Os(VIII)O4(OH)](-) complex and then the cis-[Os(VIII)O4(OH)2](2-) species. The Gibbs energy of activation for both reactions, in the forward and reverse direction, are in the range of 6-12 kcal mol(-1) and are relatively close to diffusion-controlled. The thermodynamic driving force of the first reaction is the bonding energy of the Os(VIII)-OH metal-hydroxido ligand, while of the second reaction it is the relatively large hydration energy of the doubly-charged cis-[Os(VIII)O4(OH)2](2-) product compared to the singly-charged reactants. The DFT-calculated (PBE-D3 functional) in the simulated aqueous phase (COSMO) is -2.4 kcal mol(-1) for the first reaction and -0.6 kcal mol(-1) for the second reaction and agree to within 1 kcal mol(-1) with reported experimental values, at -2.7 and 0.3 kcal mol(-1) respectively. From QTAIM and EDA analyses it is deduced that the Os(VIII)[double bond, length as m-dash]O bonding interactions are ionic (closed-shell) and that Os(VIII)-OH bonding interactions are polar covalent (dative). In contrast to QTAIM, NCI analysis allowed for the identification of relatively weak intramolecular hydrogen bonding interactions between neighbouring oxo and hydroxido ligands in both [Os(VIII)O4(OH)](-) and cis-[Os(VIII)O4(OH)2](2-) complexes. PMID:26991070

  8. On the thermodynamic properties of thermal plasma in the flame kernel of hydrocarbon/air premixed gases

    Science.gov (United States)

    Askari, Omid; Beretta, Gian Paolo; Eisazadeh-Far, Kian; Metghalchi, Hameed

    2016-07-01

    Thermodynamic properties of hydrocarbon/air plasma mixtures at ultra-high temperatures must be precisely calculated due to important influence on the flame kernel formation and propagation in combusting flows and spark discharge applications. A new algorithm based on the complete chemical equilibrium assumption is developed to calculate the ultra-high temperature plasma composition and thermodynamic properties, including enthalpy, entropy, Gibbs free energy, specific heat at constant pressure, specific heat ratio, speed of sound, mean molar mass, and degree of ionization. The method is applied to compute the thermodynamic properties of H2/air and CH4/air plasma mixtures for different temperatures (1000-100 000 K), different pressures (10-6-100 atm), and different fuel/air equivalence ratios within flammability limit. In calculating the individual thermodynamic properties of the atomic species needed to compute the complete equilibrium composition, the Debye-Huckel cutoff criterion has been used for terminating the series expression of the electronic partition function so as to capture the reduction of the ionization potential due to pressure and the intense connection between the electronic partition function and the thermodynamic properties of the atomic species and the number of energy levels taken into account. Partition functions have been calculated using tabulated data for available atomic energy levels. The Rydberg and Ritz extrapolation and interpolation laws have been used for energy levels which are not observed. The calculated plasma properties are then presented as functions of temperature, pressure and equivalence ratio, in terms of a new set of thermodynamically self-consistent correlations that are shown to provide very accurate fits suitable for efficient use in CFD simulations. Comparisons with existing data for air plasma show excellent agreement.

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

    Energy Technology Data Exchange (ETDEWEB)

    Paganini, Iván E.; Pastorino, Claudio, E-mail: pastor@cnea.gov.ar; Urrutia, Ignacio, E-mail: iurrutia@cnea.gov.ar [Departamento de Física de la Materia Condensada, Centro Atómico Constituyentes, CNEA, Av.Gral. Paz 1499, 1650 Pcia. de Buenos Aires (Argentina); CONICET, Avenida Rivadavia 1917, C1033AAJ Buenos Aires (Argentina)

    2015-06-28

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

  10. Thermodynamic properties of copper compounds with oxygen and hydrogen from first principles

    International Nuclear Information System (INIS)

    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 (Cu2O, 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 (Cu4H2O) and cupric hydride (CuH2) 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 Cu2O and water. Thus, cuprite Cu2O is the most stable of the examined Cu(I) compounds

  11. Thermodynamic properties of lead at high temperatures and high pressures-mean-field potential approach

    International Nuclear Information System (INIS)

    In the present paper, we report theoretical calculations for the thermodynamic properties of lead (Pb) at high temperatures and pressures. We use the mean-field potential (MFP) model proposed recently by Wang and Li (Phys. Rev. B 62 (2000) 196) for evaluating the vibrational contribution of the lattice ion to the total free energy. The MFP seen by the lattice ion is constructed, for the first time, in terms of the total energy-volume relation using the local pseudopotential due to Fiolhais et al. (Phys. Rev. B 51 (1995) 14001). We have calculated static compression, shock-wave compression, thermal expansion (βP), isothermal and adiabatic bulk moduli (BT and BS), internal energy, specific heats (CV and CP), thermodynamic Gruneisen parameter (γth), anharmonic contribution to the specific heat and temperature along shock Hugoniot. The results are satisfactorily comparable with those generated through first-principles methods, other theoretical methods and with experiments. We demonstrate that in comparison with other theoretical models, the present model has the advantages of computational simplicity and physical transparency

  12. Experimental and computational study of the thermodynamic properties of 2-nitrofluorene and 2-aminofluorene

    International Nuclear Information System (INIS)

    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

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

    Science.gov (United States)

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

    2015-06-01

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

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

    International Nuclear Information System (INIS)

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

  15. The thermodynamic properties of hydrated γ-Al2O3 nanoparticles

    International Nuclear Information System (INIS)

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

  16. Biosorption of cadmium(II) from aqueous solution by red algae (Ceramium virgatum): Equilibrium, kinetic and thermodynamic studies

    International Nuclear Information System (INIS)

    The biosorption characteristics of Cd(II) ions using the red alga (Ceramium virgatum) were investigated. Experimental parameters affecting the biosorption process such as pH, contact time, biomass dosage and temperature were studied. Langmuir, Freundlich and Dubinin-Radushkevich (D-R) models were applied to describe the biosorption isotherms. The biosorption capacity of C. virgatum biomass for Cd(II) ions was found to be 39.7 mg/g. From the D-R isotherm model, the mean free energy was calculated as 12.7 kJ/mol, indicating that the biosorption of Cd(II) the metal ions was taken place by chemisorption. The calculated thermodynamic parameters (ΔGo, ΔHo and ΔSo) showed that the biosorption of Cd(II) ions onto C. virgatum was feasible, spontaneous and exothermic at 293-323 K. Evaluation of experimental data in terms of biosorption kinetics showed that the biosorption of Cd(II) C. virgatum followed well pseudo-second-order kinetics

  17. Biosorption of cadmium(II) from aqueous solution by red algae (Ceramium virgatum): Equilibrium, kinetic and thermodynamic studies

    Energy Technology Data Exchange (ETDEWEB)

    Sari, Ahmet [Department of Chemistry, Gaziosmanpasa University, 60250 Tokat (Turkey); Tuzen, Mustafa [Department of Chemistry, Gaziosmanpasa University, 60250 Tokat (Turkey)], E-mail: mtuzen@gop.edu.tr

    2008-09-15

    The biosorption characteristics of Cd(II) ions using the red alga (Ceramium virgatum) were investigated. Experimental parameters affecting the biosorption process such as pH, contact time, biomass dosage and temperature were studied. Langmuir, Freundlich and Dubinin-Radushkevich (D-R) models were applied to describe the biosorption isotherms. The biosorption capacity of C. virgatum biomass for Cd(II) ions was found to be 39.7 mg/g. From the D-R isotherm model, the mean free energy was calculated as 12.7 kJ/mol, indicating that the biosorption of Cd(II) the metal ions was taken place by chemisorption. The calculated thermodynamic parameters ({delta}G{sup o}, {delta}H{sup o} and {delta}S{sup o}) showed that the biosorption of Cd(II) ions onto C. virgatum was feasible, spontaneous and exothermic at 293-323 K. Evaluation of experimental data in terms of biosorption kinetics showed that the biosorption of Cd(II) C. virgatum followed well pseudo-second-order kinetics.

  18. Thermodynamics of the Complexation of Uranium(VI) by oxalate in aqueous solution at 10-70oC

    Energy Technology Data Exchange (ETDEWEB)

    Di Bernardo, Plinio; Zanonato, Pier Luigi; Tian, Guoxin; Tolazzi, Marilena; Rao, Linfeng

    2009-03-31

    The protonation reactions of oxalate (ox) and the complex formation of uranium(VI) with oxalate in 1.05 mol kg{sup -1} NaClO{sub 4} were studied at variable temperatures (10-70 C). Three U(VI)/ox complexes (UO{sub 2}ox{sub j}{sup (2-2j){sup +}} with j = 1, 2, 3) were identified in this temperature range. The formation constants and the molar enthalpies of complexation were determined by spectrophotometry and calorimetry. The complexation of uranium(VI) with oxalate ion is exothermic at lower temperatures (10-40 C) and becomes endothermic at higher temperatures (55-70 C). In spite of this, the free energy of complexation becomes more negative at higher temperatures due to increasingly more positive entropy of complexation that exceeds the increase of the enthalpy of complexation. The thermodynamic parameters at different temperatures, in conjunction with the literature data for other dicarboxylic acids, provide insight into the relative strength of U(VI) complexes with a series of dicarboxylic acids (oxalic, malonic and oxydiacetic) and rationalization for the highest stability of U(VI)/oxalate complexes in the series. The data reported in this study are of importance in predicting the migration of uranium(VI) in geological environments in the case of failure of the engineering barriers which protect waste repositories.

  19. Fluids confined in wedges and by edges: From cluster integrals to thermodynamic properties referred to different regions

    Energy Technology Data Exchange (ETDEWEB)

    Urrutia, Ignacio, E-mail: iurrutia@cnea.gov.ar [Departamento de Física de la Materia Condensada, Centro Atómico Constituyentes, CNEA-CONICET, Av.Gral. Paz 1499, 1650 Pcia. de Buenos Aires (Argentina)

    2015-06-28

    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.

  20. Fluids confined in wedges and by edges: From cluster integrals to thermodynamic properties referred to different regions

    International Nuclear Information System (INIS)

    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