scholarly journals Temperature Dependence of Thermoelastic Properties for NaCl Crystal

2014 ◽  
Vol 2014 ◽  
pp. 1-3
Author(s):  
Kuldeep Kholiya ◽  
Jeewan Chandra
Keyword(s):  
Experimental Data ◽  
Thermal Expansion ◽  
Bulk Modulus ◽  
Volume Expansion ◽  
Close Agreement ◽  
Present Model ◽  
Harmonic Approximation ◽  
Temperature Dependent ◽  
Thermoelastic Properties ◽  
Experimental Values

Recently developed isothermal Kholiya’s EOS is modified to study the temperature dependent volume expansion and applied for NaCl crystal. The results obtained with the present model are in quite close agreement to the experimental values. The model is therefore extended to study the variation of bulk modulus and the coefficient of volume thermal expansion with temperature. Comparison of the obtained results with the experimental data demonstrates that an isothermal EOS may also be modified to study the temperature dependent elastic properties. The present study also reveals that the quasi harmonic approximation, that is, the product of bulk modulus and the coefficient of volume thermal expansion as constant, is valid in case of NaCl crystal.

TEMPERATURE DEPENDENCE OF THERMODYNAMIC PROPERTIES OF IONIC SOLIDS

2009 ◽  
Vol 23 (11) ◽  
pp. 2503-2509 ◽  
Author(s):  
S. K. SHARMA
Keyword(s):  
Experimental Data ◽  
Temperature Dependence ◽  
Volume Expansion ◽  
Close Agreement ◽  
Present Model ◽  
Expansion Ratio ◽  
Thermal Expansivity ◽  
Temperature Derivative ◽  
Computing Model ◽  
Ionic Solids

The present paper proposes a computing model for temperature dependence of volume thermal expansivity, volume expansion ratio and second order temperature derivative of volume based on the assumption that the product αKT remains constant at high temperatures and zero pressure. We have taken NaCl and KCl to testify the validity of the present model. A fairly close agreement between the calculated results and experimental data strongly supports the present model.

SIZE DEPENDENCE OF THERMOELASTIC PROPERTIES OF NANOMATERIALS

2010 ◽  
Vol 09 (05) ◽  
pp. 537-542 ◽  
Author(s):  
R. KUMAR ◽  
MUNISH KUMAR
Keyword(s):  
Experimental Data ◽  
Thermal Expansion ◽  
Bulk Modulus ◽  
Size Dependence ◽  
Young Modulus ◽  
Theoretical Method ◽  
Thermoelastic Properties ◽  
Theory And Experiment ◽  
Good Agreement

A simple theoretical method is developed to study the size dependence of bulk modulus, Young modulus, and coefficient of volume thermal expansion of nanomaterials. We have considered different nanomaterials, viz., Ni (spherical, nanofilm), α-Fe (spherical), and Cu (nanowire). The results obtained are compared with the available experimental data. A good agreement between theory and experiment supports the validity of the model developed in the present work.

scholarly journals Volumetric Properties in the NaAsO2 + H2O System at Temperature from 283.15 to 363.15 K and Atmospheric Pressure

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Hongfang Hou ◽  
Wanjing Cui ◽  
Jiaojiao Chen ◽  
Lingzong Meng ◽  
Yafei Guo ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Molar Volume ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Apparent Molar Volume ◽  
Correlation Coefficients ◽  
Apparent Molar Volumes ◽  
Temperature Dependent ◽  
Molar Volumes ◽  
Experimental Values

Densities of sodium arsenite (NaAsO2) aqueous solution with the molality varied from 0.19570 to 1.94236 mol·kg−1 at temperature intervals of 5 K from 283.15 to 363.15 K and 101 ± 5 kPa were measured by a precise Anton Paar Digital vibrating-tube densimeter. Apparent molar volumes (VΦ) and thermal expansion coefficient (α) were obtained on the basis of experimental data. The 3D diagram of apparent molar volume against temperature and molality and the diagram of thermal expansion coefficient against molality were generated. According to the Pitzer ion-interaction equation of the apparent molar volume model, the Pitzer single-salt parameters (βM,X0υ, βM,X1υ, βM,X2υ, and CM,Xυ, MX = NaAsO2) and their temperature-dependent correlation F(i, p, T) = a1 + a2ln (T/298.15) + a3(T − 298.15) + a4/(620 − T) + a5/(T − 227) (where T is temperature in Kelvin and ai are the correlation coefficients) for NaAsO2 were obtained for the first time. The predictive apparent molar volumes agree well with the experimental values, and those results indicated that the single-salt parameters and the temperature-dependent formula are reliable.

scholarly journals Thermodynamic Properties of La1-xSmxCoO3

2014 ◽  
Vol 2014 ◽  
pp. 1-5
Author(s):  
Rasna Thakur ◽  
N. K. Gaur
Keyword(s):  
Experimental Data ◽  
Thermal Expansion ◽  
Thermal Properties ◽  
Bulk Modulus ◽  
Specific Heat ◽  
Specific Heats ◽  
Lattice Specific Heat ◽  
Lattice Distortions ◽  
First Time ◽  
Rigid Ion Model

We have investigated the bulk modulus and thermal properties of La1-xSmxCoO3 (0≤x≤0.2) at temperatures 1 K≤T≤300 K probably for the first time by incorporating the effect of lattice distortions using the modified rigid ion model (MRIM). The calculated specific heat, thermal expansion, bulk modulus, and other thermal properties reproduce well with the available experimental data, implying that MRIM represents properly the nature of the pure and doped cobaltate. The specific heats are found to increase with temperature and decrease with concentration (x) for the present. The increase in Debye temperature (θD) indicates an anomalous softening of the lattice specific heat because increase in T3-term in the specific heat occurs with the decrease of concentration (x).

Modeling of Temperature-Dependent Hardness for Pure FCC and HCP Metals

2020 ◽  
Vol 12 (02) ◽  
pp. 2050022
Author(s):  
Niandong Xu ◽  
Weiguo Li ◽  
Jianzuo Ma ◽  
Yong Deng ◽  
Haibo Kou ◽  
...  
Keyword(s):  
Theoretical Model ◽  
Melting Point ◽  
Present Model ◽  
Experimental Results ◽  
Effect Of Temperature ◽  
Temperature Dependent ◽  
Different Temperatures ◽  
Pure Metals ◽  
Experimental Values ◽  
Hardness Values

In this study, a theoretical model is developed to characterize the quantitative effect of temperature on the hardness of pure FCC and HCP metals. The model is verified by comparison with the available experimental results of Cu, Al, Zn, Mg, Be, Zr, Ni, Ir, Rh, and Ti at different temperatures. Compared with the widely quoted Westbrook model and Ito–Shishokin model which need piecewise fitting to describe experimental values, the present model merely needs two hardness values at different temperatures to predict the experimental results, reducing reliance on conducting lots of experiments. This work provides a convenient method to predict temperature-dependent hardness of pure metals, and it is worth noting that it can be applied to a wide temperature range from absolute zero to melting point.

The electrical resistivities of the palladium-silver alloys

1962 ◽  
Vol 267 (1328) ◽  
pp. 139-145 ◽  
Keyword(s):  
Experimental Data ◽  
Alloy System ◽  
Residual Resistivity ◽  
Temperature Dependent ◽  
Silver Alloys ◽  
Dependent Part ◽  
Electrical Resistivities ◽  
Temperature Dependent Resistivity ◽  
Experimental Values ◽  
Pure Palladium

New measurements of resistivity as a function of com position and temperature have been made for this alloy system . Using the theoretical model proposed by Mott for s-d scattering, and experimental values for the density of states at the Fermi surface, we have calculated both the residual resistivity and temperature-dependent resistivity with very few arbitrary parameters. Striking agreement with experiment is obtained, all the features of the experimental data being reproduced except for the behaviour of the temperature-dependent part of the resistivity near pure palladium , which is ascribed to the onset of some contribution to conduction by d -band holes.

scholarly journals Метод определения параметров парного межатомного потенциала

2020 ◽  
Vol 62 (7) ◽  
pp. 998
Author(s):  
М.Н. Магомедов
Keyword(s):  
Experimental Data ◽  
Thermal Expansion ◽  
Interatomic Potential ◽  
Coefficient Of Thermal Expansion ◽  
State Equation ◽  
Zero Temperature ◽  
Thermoelastic Properties ◽  
Lennard Jones ◽  
Sublimation Energy ◽  
Potential Parameters

Disadvantages of methods known from the literature for determining 4 parameters of the paired interatomic potential of Mie-Lennard-Jones in relation to crystals are indicated. A new method is proposed for determining the parameters of this potential from the thermoelastic properties of the crystal. In this method the parameters are determined by the best coincidence of calculated values with experimental data: 1) of the sublimation energy of the crystal at zero temperature (T = 0 K) and pressure (P = 0); 2) of coefficient of thermal expansion and isothermal elastic modulus, which were measured at P = 0 and T = 300 K; 3) of the dependence of the isotherm T = 300 K state equation from volume of P(300 K, V). The method was tested on iron and gold and showed good results. By this method also were determined the interatomic potential parameters for refractory metals: Nb, Ta, Mo, and W. The results obtained also made it possible to determine more precisely such properties of these metals as the sublimation energy, the Debye temperature, and the surface energy.

scholarly journals Systematic Study of the Thermal Properties of Zeolitic Frameworks

2021 ◽  
Author(s):  
Maxime Ducamp ◽  
François-Xavier Coudert
Keyword(s):  
Mechanical Properties ◽  
Thermal Expansion ◽  
Bulk Modulus ◽  
Systematic Study ◽  
Harmonic Approximation ◽  
Negative Thermal Expansion ◽  
Great Influence ◽  
Physical Property ◽  
Thermal And Mechanical Properties ◽  
Wide Range

<div> <div> <div> <p>We report a systematic study of the thermal and mechanical properties of 134 pure SiO2 zeolites through DFT-based calculations by making use of the quasi-harmonic approximation (out of a total of 242 known fully ordered zeolitic frameworks). The comparison of our results with reported experimental data for several zeolites revealed a very good accuracy and validated our simulation methodology. We observe a wide range of thermal expansion coefficients (from −5 to −35 MK−1), highlighting the great influence of the framework topology over this physical property, while demonstrating that all pure-silica zeolites exhibit negative thermal expansion (NTE). Our simulations also provide a path for the computation of the bulk modulus for each structure, as well as its pressure and temperature dependence. Results revealed a large gamut of bulk modulus values (from 8 to 134 GPa), showing that most frameworks display pressure-induced softening — but not all! Finally, this study provides some hints to the open question of experimental feasibility of zeolitic frameworks, showing that the experimentally synthesized structures appear to have a distinct distribution of thermal and mechanical properties. </p> </div> </div> </div>

A model for evaluating and predicting high-temperature thermal expansion

1996 ◽  
Vol 11 (7) ◽  
pp. 1800-1803 ◽  
Author(s):  
Kai Wang ◽  
Robert R. Reeber
Keyword(s):  
Experimental Data ◽  
Thermal Expansion ◽  
High Temperature ◽  
Bulk Modulus ◽  
Range Data ◽  
Thermal Expansion Data ◽  
Intermediate Temperature Range ◽  
Einstein Model ◽  
Heat Curve ◽  
Work Done

In this paper, a new set of experimental data, αVKTV, representing the partial temperature derivative of the work done by the thermal pressure of the solid, is fitted by n terms of a modified Einstein model. Experimental data show that αVKTV, not αVKT, approaches a constant value at high temperature. Based on the observed linear relationship of isothermal bulk modulus with temperature at high temperature, thermal expansion can be evaluated by fitting αVKTV data. Our previous results have shown that at low temperature or for materials with less variable bulk modulus and expansivity, thermal expansion data can be simply approximated by an n term Einstein model. More generally and for many materials, αVKTV data resemble an isochoric specific heat curve. With this method, thermal expansion can be predicted at high temperatures from low and intermediate temperature range data. With accurate thermal expansion data, high temperature bulk moduli can also be predicted.

scholarly journals Temperature Dependent Variations of Phonon Interactions in Nanocrystalline Cerium Oxide

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Sugandha Dogra Pandey ◽  
Jasveer Singh ◽  
K. Samanta ◽  
Nita Dilawar Sharma ◽  
A. K. Bandyopadhyay
Keyword(s):  
Experimental Data ◽  
High Pressure ◽  
Thermal Expansion ◽  
Variation Analysis ◽  
Phonon Modes ◽  
Temperature Dependent ◽  
Anharmonic Constants ◽  
Quartic Term ◽  
Anharmonic Term ◽  
Phonon Lifetime

The temperature dependent anharmonic behavior of the phonon modes of nanocrystalline CeO2was investigated in the temperature range of 80–440 K. The anharmonic constants have been derived from the shift in phonon modes fitted to account for the anharmonic contributions as well as the thermal expansion contribution using the high pressure parameters derived from our own high pressure experimental data reported previously. The total anharmonicity has also been estimated from the true anharmonicity as well as quasiharmonic component. In the line-width variation analysis, the cubic anharmonic term was found to dominate the quartic term. Finally, the phonon lifetime also reflected the trend so observed.

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