نتایج جستجو برای: variable thermal conductivity

تعداد نتایج: 505932  

Journal: :Nanoscale 2014
Hongyang Li Hao Ying Xiangping Chen Denis L Nika Alexandr I Cocemasov Weiwei Cai Alexander A Balandin Shanshan Chen

We have investigated experimentally the thermal conductivity of suspended twisted bilayer graphene. The measurements were performed using an optothermal Raman technique. It was found that the thermal conductivity of twisted bilayer graphene is lower than that of monolayer graphene and the reference, Bernal stacked bilayer graphene in the entire temperature range examined (∼300-700 K). This find...

2017
Forouzan Ghaderi Amir H. Ghaderi Noushin Ghaderi Bijan Najafi

Background: The thermal conductivity of fluids can be calculated by several computational methods. However, these methods are reliable only at the confined levels of density, and there is no specific computational method for calculating thermal conductivity in the wide ranges of density. Methods: In this paper, two methods, an Artificial Neural Network (ANN) approach and a computational method ...

2017
Hua Jin Yu Wang Qiang Zheng Edmund Chadwick

This paper at first reports an experimental work to test the thermal conductivity of formulated sandy soil specimens of different porosities and water contents. Both needle probe and hot-plate methods were conducted and compared. It has been confirmed that the needle probe method has a better accuracy for the measurement of unsaturated soil thermal conductivity, and that the pore size distribut...

2013
Carles M. Rubio Xavier Úbeda Francesc Ferrer

The purpose of this research is to explore the variability on the soil thermal conductivity -after a prescribe fire, and to assess the effects of the ashes on the heat transfer once it’s were incorporated into the soil matrix. Sampling plot was located in the Montgrí Massif (NE of Spain). A set of 42 soil samples between surface and 5 cm depth was collected before and after the fire. To charac...

2014
Tae Sup Yun Yeon Jong Jeong Kwang-Soo Youm

The accurate assessment of the thermal conductivity of concretes is an important part of building design in terms of thermal efficiency and thermal performance of materials at various temperatures. We present an experimental assessment of the thermal conductivity of five thermally insulated concrete specimens made using lightweight aggregates and glass bubbles in place of normal aggregates. Fou...

2017
Radoslaw Chmielowski Sandip Bhattacharya Stéphane Jacob Daniel Péré Alain Jacob Kenzo Moriya Bruno Delatouche Pascal Roussel Georg Madsen Gilles Dennler

In order to reduce the thermal conductivity of CoSbS, a newly developed thermoelectric semiconductor, we have aimed at intentionally induce atomic disorder in its structure. This endeavor was guided by Density Functional Theory(DFT) calculations which indicated that substituting sulfur with selenium might be easily achievable experimentally because of the low formation energy of this point defe...

2002
J. Shewchun

Thermal conductivity, K, of two ceramic samples of T12Ba2Ca2Cus0,c has been measured over a ten-Zerature range from 300 K down to 0.1 K. At high temperatures, the data show features similar to the thermal conductivity of Y-Ba-Cu-0 and Bi-Sr-CaCu-0 ceramics in both the magnitude and the temperature dependence. Specifically, a sudden increase in the thermal conductivity is observed at the onset o...

2013
M.S.A. El-Kader

An approximate empirical isotropic interatomic potentials for CH4-inert gas mixtures are developed by simultaneously fitting the Exponential-Spline-Morse-Spline-van der Waals (ESMSV) potential form to viscosity, thermal conductivity, thermal diffusion factors, diffusion coefficient, interaction second pressure virial coefficient and scattering cross-section data. Quantum mechanical lineshapes o...

2013
Renga Rao Krishnamoorthy

The prime aim of this study was to investigate the thermal conductivity of concrete using crushed recycled glass as a fine aggregate. Influencing factors on thermal conductivity of concrete are investigated using The Unitherm Model 6000 Guarded Hot Plate Thermal Conductivity Instrument. A total of 36 concrete mixes were produced with different water cement ratios (0.4 and 0.5). Recycled glass w...

2017
Ali Kandemir Ayberk Ozden Tahir Cagin Cem Sevik

Various theoretical and experimental methods are utilized to investigate the thermal conductivity of nanostructured materials; this is a critical parameter to increase performance of thermoelectric devices. Among these methods, equilibrium molecular dynamics (EMD) is an accurate technique to predict lattice thermal conductivity. In this study, by means of systematic EMD simulations, thermal con...

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