A molecular dynamic study of change in thermodynamic functions of silicon FCC cell with the change in temperature

In modern days silicon is being extensively used in making electronic semiconductor-based chips and ICs. In this research, the change in different thermodynamic properties of silicon like lattice heat capacity, molar enthalpy and Debye temperature at constant pressure, with the change in temperature, has been investigated by using molecular dynamics (MD) simulation method. Knowing silicon thermodynamic functions are quite important, because many electronic companies are nowadays trying a lot to reduce the heat generated by their semiconductor chips as excessive heating of the chip not only warms up the device quickly but also reduces the chip life. The results obtained from this simulation help engineers to design electronic chips more efficiently. For simulation Accelrys Materials Studio (Version 5.0) software has been used. The simulation was run for silicon FCC diamond structured cell. The analysis tool used in the simulation is known as CASTEP (Cambridge Sequential Total Energy Package). This tool is specialized for performing molecular level thermodynamic analysis to generate data and graphs for the change in different temperature dependent properties of the molecular system. The interaction between silicon atoms was expressed by the Kohn-Sham potential and MD calculation was conducted on crystalline state of silicon at temperatures between 0 and 1000 K. Here, density function theory (DFT) based tool has been used to derive density of state relations. Results obtained by the simulation were compared with published experimental values and it was found that the simulation results were close to the experimental values.

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A variable property heat transfer model for predicting soil temperature profiles during simulated wildland fire conditions

International Journal of Wildland Fire ◽

10.1071/wf07002 ◽

2008 ◽

Vol 17 (2) ◽

pp. 205 ◽

Cited By ~ 6

Author(s):

Ebenezer K. Enninful ◽

David A. Torvi

Keyword(s):

Heat Transfer ◽

Thermal Properties ◽

Wildland Fire ◽

Heat Fluxes ◽

Transfer Model ◽

Temperature Dependent ◽

Heat Penetration ◽

Experimental Values ◽

Temperature Dependent Properties ◽

Plant Shoots

A numerical model of heat transfer in dry soil was developed to predict temperatures and depth of lethal heat penetration during cone calorimeter tests used to simulate wildland fire exposures. The model was used to compare predictions made using constant and temperature-dependent thermal properties with experimental results for samples of dry sand exposed to heat fluxes of 25, 50 and 75 kW m–2. Depths of lethal heat penetration predicted using temperature-dependent properties were within 2 to 10% of the values determined using measured temperatures, while predictions made using constant properties were within 10 to 21% of the experimental values. In both cases, predictions made by the model were within the 1-cm accuracy with which the depth of seeds and plant shoots in the soil can be determined in practice. The model generally over-predicted the depth of lethal heat penetration in dry or moist soil when temperature-dependent properties were used, and over-predicted the depth of lethal heat penetration in soils with a moisture content of greater than 10% if constant thermal properties were used.

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Temperature-Dependent Properties of Molten Li2BeF4 Salt Using Ab Initio Molecular Dynamics

ACS Omega ◽

10.1021/acsomega.1c02528 ◽

2021 ◽

Author(s):

Khagendra Baral ◽

Saro San ◽

Ridwan Sakidja ◽

Adrien Couet ◽

Kumar Sridharan ◽

...

Keyword(s):

Molecular Dynamics ◽

Ab Initio ◽

Ab Initio Molecular Dynamics ◽

Temperature Dependent ◽

Temperature Dependent Properties

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Green’s function for an elastic layer with temperature-dependent properties

Materials Science ◽

10.1007/s11003-013-9544-z ◽

2013 ◽

Vol 48 (5) ◽

pp. 607-613 ◽

Cited By ~ 3

Author(s):

S. J. Matysiak ◽

D. M. Perkowski

Keyword(s):

Green’S Function ◽

Green's Function ◽

Elastic Layer ◽

Temperature Dependent ◽

Temperature Dependent Properties

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Crystal structure and temperature-dependent properties of Na2H4Ga2GeO8 – a novel gallogermanate

Zeitschrift für Naturforschung B ◽

10.1515/znb-2020-0159 ◽

2020 ◽

Vol 75 (9-10) ◽

pp. 805-813

Author(s):

Irma Peschke ◽

Lars Robben ◽

Christof Köhler ◽

Thomas Frauenheim ◽

Josef-Christian Buhl ◽

...

Keyword(s):

Crystal Structure ◽

Decomposition Temperature ◽

Spectroscopic Techniques ◽

Charge Balance ◽

Temperature Dependent ◽

Raman Spectroscopic ◽

Debye Temperatures ◽

Diffraction Lattice ◽

Temperature Dependent Properties ◽

Balance Structure

AbstractSynthesis, crystal structure and temperature-dependent behavior of Na2H4Ga2GeO8 are reported. This novel gallogermanate crystallizes in space group I41/acd with room-temperature powder diffraction lattice parameters of a = 1298.05(1) pm and c = 870.66(1) pm. The structure consists of MO4 (M = Ga, Ge) tetrahedra in four-ring chains, which are connected by two different (left- and right-handed) helical chains of NaO6 octahedra. Protons coordinating the oxygen atoms of the GaO4 tetrahedra not linked to germanium atoms ensure the charge balance. Structure solution and refinement are based on single crystal X-ray diffraction measurements. Proton positions are estimated using a combined approach of DFT calculations and NMR, FTIR and Raman spectroscopic techniques. The thermal expansion was examined in the range between T = 20(2) K and the compound’s decomposition temperature at 568(5) K, in which no phase transition could be observed, and Debye temperatures of 266(11) and 1566(65) K were determined for the volume expansion.

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A new boundary element algorithm for modeling and simulation of nonlinear thermal stresses in micropolar FGA composites with temperature-dependent properties

Advanced Modeling and Simulation in Engineering Sciences ◽

10.1186/s40323-021-00193-6 ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

Mohamed Abdelsabour Fahmy

Keyword(s):

Modeling And Simulation ◽

Boundary Element ◽

Thermal Stresses ◽

Computation Time ◽

Functionally Graded ◽

Temperature Dependent ◽

Time Step ◽

Kirchhoff Transformation ◽

Nonlinear Temperature ◽

Temperature Dependent Properties

AbstractThe main aim of this article is to develop a new boundary element method (BEM) algorithm to model and simulate the nonlinear thermal stresses problems in micropolar functionally graded anisotropic (FGA) composites with temperature-dependent properties. Some inside points are chosen to treat the nonlinear terms and domain integrals. An integral formulation which is based on the use of Kirchhoff transformation is firstly used to simplify the transient heat conduction governing equation. Then, the residual nonlinear terms are carried out within the current formulation. The domain integrals can be effectively treated by applying the Cartesian transformation method (CTM). In the proposed BEM technique, the nonlinear temperature is computed on the boundary and some inside domain integral. Then, nonlinear displacement can be calculated at each time step. With the calculated temperature and displacement distributions, we can obtain the values of nonlinear thermal stresses. The efficiency of our proposed methodology has been improved by using the communication-avoiding versions of the Arnoldi (CA-Arnoldi) preconditioner for solving the resulting linear systems arising from the BEM to reduce the iterations number and computation time. The numerical outcomes establish the influence of temperature-dependent properties on the nonlinear temperature distribution, and investigate the effect of the functionally graded parameter on the nonlinear displacements and thermal stresses, through the micropolar FGA composites with temperature-dependent properties. These numerical outcomes also confirm the validity, precision and effectiveness of the proposed modeling and simulation methodology.

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