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An analytical consideration has been made to explore the velocity, temperature and nanoparticle distributions and heat transfer characteristics associated with thermal dispersion and nanoparticle mechanical dispersion within a nanofluid-saturated homogeneous metal foam. A volume-averaging theory was rigorously applied to integrate locally a set of governing equations based on the modified Buongiorno model at the pore scale. Thus, a macroscopic set of volume-averaged governing equations were derived allowing interstitial heat transfer between the nanofluid and metal phases. Unknown terms were modelled mathematically to obtain a closed set of volume-averaged governing equations. Subsequently, a pore-scale analysis was carried out to find possible functional forms for describing thermal dispersion and nanoparticle mechanical dispersion in a nanofluid-saturated metal foam. Using the resulting set of volume-averaged governing equations, forced convective flows in nanofluid-saturated metal foams were analytically investigated for the steady-state case. Eventually, it has been predicted that an unconventionally high level of the heat transfer rate (about 80 times more than the case of base fluid convection without a metal foam) may be achieved by combination of metal foam and nanofluid.

Mg2Si/MgO nanofibers were synthesized by the heat treatment of amorphous SiO2 nanofibers in Mg vapor, and their morphological and structural properties were then investigated. Well-aligned Mg2Si/MgO nanofibers with high density were synthesized, which preserves the general morphology of the original SiO2 nanofibers. The morphology and crystalline quality of Mg2Si/MgO nanofibers depend on the reaction temperature. This reaction provides a low cost method to synthesize nanoscale thermoelectric materials with high crystalline quality to enhance thermoelectric properties.

The hexagonal phase MoSi2 was grown using MoS2 powder as the source material by the molten salt method. The structural and morphological properties of the resultant silicides are characterized. As a comparison, the structural and compositional characterizations were made for the Mo-silicides grown on a Mo substrate and a Mo-Ti alloy compact. It was revealed that the homogeneity of the chemical composition of the silicides grown using MoS2 is improved, except for the existence of the Si source powders, though a small amount of S remained in the powder. The layered structure of MoS2 with a hexagonal crystalline structure would affect the growth morphology and enhance the formation of the hexagonal MoSi2. A simple growth procedure to fix the crystalline structure using an appropriate starting material under a preferable growth environment is proposed.

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