scholarly journals Thermodynamic properties of CO 2 up to 3000 atmospheres between 25 and 150°C

1937 ◽  
Vol 160 (902) ◽  
pp. 376-384 ◽  
Keyword(s):  
Free Energy ◽  
Thermodynamic Properties ◽  
Total Energy ◽  
Specific Heat ◽  
Interpolation Formula ◽  
Constant Volume ◽  
Present Communication ◽  
Different Temperatures

In previous papers (Michels and Michels 1935; Michels, Michels and Wouters 1935) the results of isotherm measurements on CO 2 and a method for interpolation of the pv values at intermediate temperatures and densities have been published. From the data obtained, the specific heat at constant volume C v , the free energy F , the total energy U , and the entropy S , have been calculated, and these results are given in the present communication. The values of F, U and S at N. T. P. have been taken as zero. The values of C v , F, S and U at a density of 1 Amagat unit ( ρ = 1) have first been calculated for different temperatures. To the values, so obtained, has been added the increase of these quantities by compression. The values of C v at ρ = 1 have been calculated, using the interpolation formula as given by Shilling and Partington (1928).

scholarly journals Kinetics and thermodynamic properties related to the drying of 'Cabacinha' pepper fruits

2016 ◽  
Vol 20 (2) ◽  
pp. 174-180 ◽  
Author(s):  
Hellismar W. da Silva ◽  
Renato S. Rodovalho ◽  
Marya F. Velasco ◽  
Camila F. Silva ◽  
Luís S. R. Vale
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Free Energy ◽  
Thermodynamic Properties ◽  
Gibbs Free Energy ◽  
Removal Rate ◽  
Effective Diffusion ◽  
Drying Time ◽  
Three Samples ◽  
Different Temperatures

ABSTRACT The objective of this study was to determine and model the drying kinetics of 'Cabacinha' pepper fruits at different temperatures of the drying air, as well as obtain the thermodynamic properties involved in the drying process of the product. Drying was carried out under controlled conductions of temperature (60, 70, 80, 90 and 100 °C) using three samples of 130 g of fruit, which were weighed periodically until constant mass. The experimental data were adjusted to different mathematical models often used in the representation of fruit drying. Effective diffusion coefficients, calculated from the mathematical model of liquid diffusion, were used to obtain activation energy, enthalpy, entropy and Gibbs free energy. The Midilli model showed the best fit to the experimental data of drying of 'Cabacinha' pepper fruits. The increase in drying temperature promoted an increase in water removal rate, effective diffusion coefficient and Gibbs free energy, besides a reduction in fruit drying time and in the values of entropy and enthalpy. The activation energy for the drying of pepper fruits was 36.09 kJ mol-1.

scholarly journals Anharmonic Contributions to the Vibratory Free Energy of a Lattice

1964 ◽  
Vol 17 (3) ◽  
pp. 269 ◽  
Author(s):  
P Lloyd
Keyword(s):  
Free Energy ◽  
Specific Heat ◽  
Constant Volume ◽  
Bethe Approximation ◽  
Rate Of Increase

The anharmonic contribution to the free energy of a lattice is evaluated by means of a Bethe approximation. The approximation is accurate to within 3% for the model valuated by Maradudin, Flinn, and Coldwell� Horsfall. The anharmonic contribution to the specific heat at constant volume of a model of sodium is evaluated.The specific heat is found to increase as the temperature rises but the rate of increase is lower than the observed value

Mechanical and thermodynamic properties of AlX (X = N, P, As) compounds

2017 ◽  
Vol 31 (23) ◽  
pp. 1750167 ◽  
Author(s):  
Lifang Xu ◽  
Wei Bu
Keyword(s):  
Thermodynamic Properties ◽  
Specific Heat ◽  
Atomic Number ◽  
Phonon Dispersion ◽  
Theoretical Data ◽  
Constant Volume ◽  
Vibrational Entropy ◽  
Debye Temperatures ◽  
The Difference ◽  
Good Agreement

The Vickers hardness of various AlX (X = N, P, As) compound polymorphs were calculated with the bond resistance model. Thermodynamic properties, such as vibrational entropy, constant volume specific heat and Debye temperatures, were calculated using phonon dispersion relations and phonon density of states (DOS). The calculated values are in good agreement with the previous experimental and theoretical data. For the same structure of AlX (X = N, P, As) compounds, their hardness and Debye temperatures both decrease with the X atomic number. The wurtzite (wz) and zincblende (zb) structures of the same compounds AlX share an almost identical hardness, but have different Debye temperatures. The difference between wz and zb structures increases as the atomic number of X increases. The thermodynamic properties reveal that the constant volume specific heat approaches the Dulong–Petit rule at high temperatures.

Thermodynamics of a 3 — D charged rotating hairy black hole

Open Physics ◽  
2014 ◽  
Vol 12 (9) ◽  
Author(s):  
Jalil Naji ◽  
Saba Heydari ◽  
Ali Amjadi
Keyword(s):  
Phase Transition ◽  
Black Hole ◽  
Free Energy ◽  
Total Energy ◽  
Specific Heat ◽  
Three Dimensions ◽  
Study Phase ◽  
First Law Of Thermodynamics ◽  
The Stability ◽  
Hairy Black Hole

AbstractIn this paper, we consider a charged rotating black hole in three dimensions with a scalar charge, and discuss thermodynamics quantities. We find effects of the black hole parameters on the temperature, entropy, free energy, total energy and specific heat. We also investigate the stability of the black hole and study phase transition. We consider the first law of thermodynamics and find that satisfied.

scholarly journals LOWEST ORDER CONSTRAINED VARIATIONAL CALCULATION FOR POLARIZED LIQUID 3He AT FINITE TEMPERATURE

2009 ◽  
Vol 23 (01) ◽  
pp. 113-123 ◽  
Author(s):  
G. H. BORDBAR ◽  
M. J. KARIMI ◽  
J. VAHEDI
Keyword(s):  
Free Energy ◽  
Thermodynamic Properties ◽  
Variational Method ◽  
Specific Heat ◽  
Finite Temperature ◽  
Variational Calculation ◽  
Saturation Density ◽  
Energy Entropy ◽  
Spin Polarized

We have investigated some of the thermodynamic properties of spin-polarized liquid 3 He at finite temperature using the lowest order constrained variational method. For this system, the free energy, entropy and pressure are calculated for different values of the density, temperature and polarization. We have also presented the dependence of specific heat, saturation density and incompressibility on temperature and polarization.

scholarly journals Kinetic Study of Epoxidation of Rubber Seed Oil Using Tungstate-based Catalyst

2018 ◽  
Vol 34 (4) ◽  
Author(s):  
Nguyễn Thị Thủy
Keyword(s):  
Free Energy ◽  
Thermodynamic Properties ◽  
Seed Oil ◽  
Endothermic Reaction ◽  
Rubber Seed Oil ◽  
Rubber Seed ◽  
Epoxidation Reaction ◽  
Suitable Temperature ◽  
Different Temperatures ◽  
Specific Temperature

By performing the reaction for one hour at three different temperatures, the thermodynamic properties of the epoxidation reaction using tungstate-based catalyst of RSO and eRSO were determined. The rate constant of these epoxidation reactions were varied from 0.57.10-2 to 1.01.10-2 l.mol-1.s-1 with RSO and 0.97.10-2 to 1.76.10-2 l.mol-1.s-1 with eRSO. The activated energies of reaction were 6.2 and 6.6 kcal.mol-1, respectively. The enthalpy ΔH was positive indicating that the epoxidation process was a endothermic reaction, but the free-energy ΔF was also positive, so there was a specific temperature at which the epoxidation process was the most effective. Experimental results showed that 60oC was the most suitable temperature for epoxidation reaction of both RSO and eRSO with the conversion of 91.37% (RSO) and 94.87% (eRSO), the yield of 75.06% (RSO) and 89.56% (eRSO) and the selectivity was 0.82 (RSO) and 0.94 (eRSO), respectively.

Ab initio study of thermodynamic properties of bulk zinc-blende CdS: Comparing the LDA and GGA

2018 ◽  
Vol 32 (20) ◽  
pp. 1850207 ◽  
Author(s):  
Fatemeh Badieian Baghsiyahi ◽  
Arsalan Akhtar ◽  
Mahboubeh Yeganeh
Keyword(s):  
Free Energy ◽  
Thermal Expansion ◽  
Thermodynamic Properties ◽  
Bulk Modulus ◽  
Internal Energy ◽  
Density Functional ◽  
Helmholtz Free Energy ◽  
Constant Volume ◽  
Grüneisen Parameter ◽  
Zinc Blende

In the present study, we have investigated the phonon and thermodynamic properties of bulk zinc-blende CdS by first-principle calculations within the density functional theory (DFT) and the density functional perturbation theory (DFPT) method using the quasi harmonic approximation (QHA). We calculated the phonon dispersion at several high symmetry directions, density of phonon state, temperature dependence feature of Helmholtz free energy (F), internal energy, bulk modulus, constant-volume specific heat, entropy, coefficient of the volume thermal expansion and Grüneisen parameter estimated with the local density approximation (LDA) and generalized gradient approximation (GGA) for the exchange-correlation potential and compared them with each other. For internal energy, Helmholtz free energy, constant volume heat capacity and phonon entropy the LDA and GGA results are very similar. But, the LDA gives lattice constants that are smaller than GGA while phonon frequencies, bulk modulus and cohesive energies are larger. On the other hand, the results obtained through the GGA approximation for the coefficient of the volume thermal expansion and Grüneisen parameter are larger than those obtained from LDA.

THERMODYNAMIC AND MAGNETIC PROPERTIES OF THE ARCHIMEDEAN LATTICES

2005 ◽  
Vol 19 (28) ◽  
pp. 4259-4267 ◽  
Author(s):  
Q. L. ZHANG
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Magnetic Properties ◽  
Free Energy ◽  
Thermodynamic Properties ◽  
Specific Heat ◽  
Internal Energy ◽  
Type 3 ◽  
Ising Spins ◽  
Frustration Effects

We numerically study the thermodynamic properties of two Archimedean lattices1 with Ising spins using Wang–Landau algorithm of the Monte Carlo simulation. The two Archimedean lattices are of the type (3, 122) and Kagomé, for which we are particularly interested in the frustration effects. The internal energy, specific heat, free energy, entropy, magnetization and spin susceptibility are calculated.

A First Principles Study of Thermal Properties of Yb-Pnictides (YbX, X= N, P and As) Compounds

2013 ◽  
Vol 665 ◽  
pp. 353-358
Author(s):  
Himadri R. Soni ◽  
Prafulla K. Jha
Keyword(s):  
Free Energy ◽  
Thermal Properties ◽  
Specific Heat ◽  
Internal Energy ◽  
First Principles ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Constant Volume ◽  
Generalized Gradient ◽  
Lattice Specific Heat

Using first principles density functional theoretical calculations within the generalized gradient approximation (GGA), the present paper reports thermal properties such as constant volume lattice specific heat, Gibbs free energy, internal energy, and entropy of Yb-pnictides such as YbN, YbP and YbAs in its rocksalt phase. The variation of lattice specific heat with temperature obeys the classical Dulong-Petits law at high temperature while at low temperature it obeys Debye T3 law. The internal energy, entropy and free energy show a gradual variation with temperature. The specific heat at constant volume at lower temperature increases as going from N to P to As. *Corresponding author Email: [email protected], [email protected] Telephone: +91-278-2422650 Fax: +91-278-2426706

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