This paper reports temperature-dependent thermal conductivity measurements in the crossplane direction of symmetrically strained Si/Ge superlattices, and the effect of doping, period thickness and dislocations on the thermal conductivity reduction of Si/Ge superlattices. The Si/Ge superlattices are grown by molecular beam epitaxy on silicon and siliconon-insulator substrates with a graded buffe...

0017-9310/$ see front matter 2008 Elsevier Ltd. A doi:10.1016/j.ijheatmasstransfer.2008.10.027 * Corresponding author. E-mail address: [email protected] (D.G. The efficiency of a thermoelectric material is measured by the figure of merit ZT, which is inversely proportional to the thermal conductivity. Superlattice structures often have a reduced thermal conductivity because of the intr...

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...

We present a thermal conductivity measurement method for laser crystals based on thermal mapping of the crystal face by an infrared camera. Those measurements are performed under end-pumping of the laser crystal and during laser operation. The calculation of the fraction of pump power converted into heat is therefore simplified, and it is possible to link easily the temperature in the crystal t...

Thermal conductivity of the Earth's lower mantle greatly impacts the mantle convection style and affects the heat conduction from the core to the mantle. Direct laboratory measurement of thermal conductivity of mantle minerals remains a technical challenge at the pressure-temperature (P-T) conditions relevant to the lower mantle, and previously estimated values are extrapolated from low P-T dat...

Nanoporous silicon is known to have a thermal conductivity that is orders of magnitude smaller than the bulk crystalline silicon from which it is formed. Even though the strong columnar microscopic structure of porous silicon indicates the possibility of highly anisotropic thermal properties, there have been no measurements. We report here an experimental investigation of this anisotropy. An an...

Nanofluids are gaining much importance over the past decade due to their enhanced thermal conductivity, specific heat, cooling capacity, electrical conductivities. Novel properties of nanofluids are yet to be explored to the highest potential applications. One of the prominent applications of nanofluids is in thermal conduction. The presence of nanoparticle in a fluid can enhance the thermal co...

Nanofluids are gaining much importance over the past decade due to their enhanced thermal conductivity, specific heat, cooling capacity, electrical conductivities. Novel properties of nanofluids are yet to be explored to the highest potential applications. One of the prominent applications of nanofluids is in thermal conduction. The presence of nanoparticle in a fluid can enhance the thermal co...

In this study, nanofluids of Chromium (Cr) in water, Ethylene Glycol and Ethanol have been prepared using single step method. The thermal conductivity and diffusivity of these nanofluids were measured via hot wire-photothermal deflection technique. Based on finite difference method (FDM) temperature distribution and photothermal deflection caused by the hot wire inside nanofluids was obtained. ...

A tool for evaluating thin-film thermal conductivity to submicron spatial resolution has been developed. The micro-instrumentation utilizes the thermoreflectance (TR) technique to characterize thermal conductivity and material uniformity. The instrument consists of a heating element for creating temperature gradients and an Invar bar with in situ temperature monitoring for heat flux measurement...