Efficient numerical simulation of ac conduction in heterogeneous materials at low temperatures

2005 ◽  
Vol 71 (9) ◽  
Author(s):  
Muhammad Sahimi ◽  
Maryam Naderian ◽  
Fatemeh Ebrahimi
Keyword(s):  
Numerical Simulation ◽  
Low Temperatures ◽  
Heterogeneous Materials ◽  
Ac Conduction

The magnetic states and Labyrinth ordering in 2D lattices of ising spins with RKKY Interaction

2015 ◽  
Vol 06 (02) ◽  
pp. 1550012
Author(s):  
Konstantin Nefedev ◽  
Valery Belokon ◽  
Vitalii Kapitan ◽  
Olga Dyachenko
Keyword(s):  
Numerical Simulation ◽  
Low Temperatures ◽  
Hysteresis Loops ◽  
Square Lattice ◽  
Magnetization Distribution ◽  
Rkky Interaction ◽  
Domain Structures ◽  
Physical Experiments ◽  
Magnetic States ◽  
Ising Spins

The numerical simulation of 2D simple square lattice of Ising superspins, that interact via the Ruderman–Kittel–Kasuya–Yosida (RKKY) exchange interaction is performed. It is found, that at low temperatures in the researched systems predominantly realized labyrinth domain structure. The modeled image of magnetization distribution does not coincide with the image of energy distribution. Hysteresis loops of the samples and labyrinth domain structures similarly obtained by Monte Carlo method, are also observed in physical experiments.

scholarly journals An analysis of effective thermal conductivity of heterogeneous materials

2014 ◽  
Vol 14 (1) ◽  
pp. 14-21 ◽  
Author(s):  
Guocheng Zhu ◽  
Dana Kremenakova ◽  
Yan Wang ◽  
Jiri Militky ◽  
Funda Buyuk Mazari
Keyword(s):  
Thermal Conductivity ◽  
Numerical Simulation ◽  
Thermal Property ◽  
Effective Thermal Conductivity ◽  
Contact Area ◽  
Heterogeneous Materials ◽  
Inclusion Size ◽  
Analytical Models ◽  
Important Index ◽  
Inclusion Shape

Abstract Effective thermal conductivity (ETC) is a very important index for evaluating the thermal property of heterogeneous materials, which include more than two different kinds of materials. Several analytical models were proposed for predicting the ETC of heterogeneous materials, but in some cases, these models cannot provide very accurate predictions. In this work, several analytical models and numerical simulations were studied in order to investigate the differences among them. In addition, some factors which would influence the ETC of heterogeneous materials were investigated by numerical simulation. The results demonstrated that the numerical simulation can provide very accurate prediction, indicated that different analytical models should be selected to predict specific problems based on their assumptions, and suggested that more variables need to be considered in order to improve these analytical models, such as inclusion shape, inclusion size, distribution of inclusions and contact area. Besides, numerical method could be an effective and reliable way to obtain the ETC of heterogeneous materials with any kind of complicated structures.

Heat and Mass Transfer at Low Temperatures, in a Trapezoidal Closed Cavity

2012 ◽  
Vol 550-553 ◽  
pp. 2996-3003 ◽  
Author(s):  
M.S. Maalem ◽  
A. Benzaoui
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Experimental Study ◽  
Low Temperatures ◽  
The Other ◽  
Flowing Water ◽  
Closed Cavity ◽  
Nusselt Numbers ◽  
Future Paper ◽  
The Mean

An experimental study, in a trapezoidal closed cavity had been led in our laboratory. The considered cavity includes a vaporizing horizontal surface, two condensing ones; one is of glass and the other of aluminium surface. It is cooled down by flowing water. The other walls are thermally isolated. Acquired results allowed to identify the regime of air flow inside the cavity, to assess the mean exchange coefficients of heat and mass, across the three walls and to write a correlation for the mean Sherwood and Nusselt numbers, established for laminar flow regime. These results are important to model many solar uses as solar distillers, solar dryers, etc… We present, in this report experimental results and in a future paper, the written mathematical model and a numerical simulation.

NUMERICAL SIMULATION OF THE HIGH-Tc SUPERCONDUCTORS

1988 ◽  
Vol 02 (05) ◽  
pp. 975-980 ◽  
Author(s):  
I. Morgenstern
Keyword(s):  
Numerical Simulation ◽  
Low Temperatures ◽  
Nearest Neighbor ◽  
Nearest Neighbors ◽  
Repulsive Interaction ◽  
Phonon Coupling ◽  
High Tc Superconductors ◽  
High Tc ◽  
Sign Problem ◽  
Electron Phonon Coupling

Monte Carlo simulations based on the Trotter-Suzuki transformation were carried out using 6 × 6 and 12 × 12 lattices and the single-band Hubbard model with intermediate-range repulsive interaction. The absence of the "minus-sign problem" for sufficiently low temperatures and appropriate doping indicates bosonic behavior reminiscent of superconductivity. It was found that holes prefer to pair on next-nearest-neighbor sites while nearest neighbors are suppressed. Additional electron-phonon coupling in the form of the breathing mode not only preserves this symmetry but strengthening of the bosonic background indicates the possibility of superconductivity.

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