نتایج جستجو برای: effective thermal conductivity

تعداد نتایج: 921897  

Objective(s): This study aims to evaluate and predict the thermal conductivity of iron oxide nanofluid at different temperatures and volume fractions by artificial neural network (ANN) and correlation using experimental data. Methods: Two-layer perceptron feedforward artificial neural network and backpropagation Levenberg-Marquardt (BP-LM) tra...

2007
Bhasker Gahtori Ratan Lal S K Agarwal M A H Ahsan Ashok Rao Y F Lin K M Sivakumar Y-K Kuo

Thermal conductivity κ(T ) and thermoelectric power S(T ) studies on (Y,Gd)Ba2(Cu1−xMnx)3O7−δ (x 0.02) superconductors are presented here. Thermal conductivity for all the samples exhibits a hump below the superconducting transition temperature Tc. The peak height of the hump decreases with the Mn content in both the Yand Gd-based systems, barring GdBa2(Cu0.99Mn0.01)3O7−δ. The peak height reduc...

2011
Steve Choi

As a hot research topic nanofluids have attracted great interest from researchers worldwide. Although nanofluids are found to exhibit higher thermal conductivity compared to their base fluids, the underlying mechanisms for the enhancement are still debated and not fully understood. In addition, there has been little agreement among different studies and no widely accepted model is also availabl...

2017
Hyun-sik Kim Kyu Hyoung Lee Joonyeon Yoo Jehun Youn Jong Wook Roh Sang-il Kim Sung Wng Kim

Cation substitutional doping is an effective approach to modifying the electronic and thermal transports in Bi₂Te₃-based thermoelectric alloys. Here we present a comprehensive analysis of the electrical and thermal conductivities of polycrystalline Pb-doped p-type bulk Bi0.48Sb1.52Te₃. Pb doping significantly increased the electrical conductivity up to ~2700 S/cm at x = 0.02 in Bi0.48-xPbxSb1.5...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه اراک - دانشکده علوم پایه 1389

انتقال سریع و آسان گرما از مهمترین مسائل صنعت انتقال گرماست. نانوسیالات انواع جدیدی از سیالات هستند که از پراکنده سازی نانوذرات در سیالات پایه تهیه می شوند. تکنولوژی نانوسیال، چالش جدیدی برای هدایت گرمایی سیالات پایه است. دلیل این چالش، هدایت گرمایی نسبتا زیاد نانوسیالات نسبت به سیالات پایه است. در این تحقیق نانوسیال جدیدی که علاوه بر هدایت گرمایی زیاد، ویسکوزیته مناسبی نیز داشته باشد، مورد برر...

2002
Jun Xu Richard A. Wirtz

A conductive laminate consisting of stacked two-dimensional plain-weave screen with an arbitrary weave angle is described. Similar to orthogonal screen laminates, these porous matrices can be fabricated to have a wide range of porosity, ε and specific surface area, ß; and the structure can have a highly anisotropic thermal conductivity vector, with in -plane effective thermal conductivities ran...

2008
E Bauer Ch Paul St Berger S Majumdar H Michor M Giovannini A Saccone A Bianconi

Thermal conductivity of superconducting MgB 2 was studied in both the superconducting and the normal state region. The latter is almost equally determined by the electronic-and the lattice contribution to the total thermal conductivity. In the superconducting state, however, the lattice contribution is larger. The electronic thermal conductivity below T c was derived from the experimental data ...

2013
A. Selvakumar P. V. Mohanram

Conventionally, cast iron is the material used for high speed machine tool structures. As an alternate material to improve the structural properties, composite materials are being used, which are known to exhibit excellent thermal and mechanical properties. While selecting an alternate material, thermal conductivity is an important thermo physical property of the material that should be studied...

2008
Basked Ganapathysubramanian Nicholas Zabaras

A simple stochastic up-scaling strategy is presented for incorporating the effects of micro-scale variations of thermal conductivity in the thermal analysis of macro-scale systems. Incomplete characterization of the fine-scale variation necessitates posing the thermal conductivity as a stochastic multiscale random field. A data-driven approach coupled with a non-linear dimension reduction algor...

2011
Jin Fang Laurent Pilon Henry Samueli

This study establishes that the effective thermal conductivity keff of crystalline nanoporous silicon is strongly affected not only by the porosity fv and the system’s length Lz but also by the pore interfacial area concentration Ai. The thermal conductivity of crystalline nanoporous silicon was predicted using non-equilibrium molecular dynamics simulations. The Stillinger-Weber potential for s...

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