Half-Heusler compounds such as MNiSn for n-type and MCoSb for p-type, M = Ti, Zr, Hf, show relatively high thermoelectric figure of merit (ZT = ∼0.8 for MNiSn and ∼0.5 for MCoSb) at 700–1000 K, thereby they are known as promising high-performance thermoelectric materials applicable for power generation devices in exhaust heat recovery systems of automobiles. Recently, the ZT values have been improved by applying various methods such as nanostructuring and band engineering, and ZT > 1 have been achieved in some half-Heusler compounds. In addition, a new p-type half-Heusler compound FeNbSb has been developed. In this review, we summarize the history of half-Heusler compounds as thermoelectric materials and review the representative results for their improved thermoelectric properties.

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Copper acetylide is an well-known explosive compound. However, when the size of their crystals is reduced to the nanoscale, their explosive nature is lost, owing to a much lower thermal conductance that inhibits explosive chain reactions. This less explosive character can be exploited for the production of new carbon materials. Generally, amorphous carbon is prepared by carbonization of organic compounds exposed to high temperature, which can induce partial crystallization in graphite. In this work, we present a new method in which the carbonization reaction can proceed at a lower annealing temperature owing to the highly reactive nature of copper acetylide, thus avoiding crystallization processes and enabling the production of genuinely amorphous carbon materials.

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Large surface energy can be developed using highly porous Heterogeneous Lyophobic Systems (HLSs) which comprise a mesoporous solid and a non-wetting liquid to make working bodies. Such systems exhibit remarkable properties and characteristics such as high energy capacity, capability to simultaneously store (and restore) both thermal and mechanical energy during intrusion/extrusion of the liquid during compression/decompression operations. Usually an HLS is in the form of a suspension of a porous powder in the liquid. We have developed a P,V,T-calorimetry-volumetry system which can judicially be used to submit such suspension to compression/ decompression in a perfectly controlled thermodynamic way over extended T- and P-ranges. As a matter of fact, depending on the nature of the porous solid and of the non-wetting liquid it is always possible to find a high enough pressure to force the intrusion by compression of the liquid in the pores of the solid. The compression energy being store in the system can be further restored. We show how easily we can obtain the thermal and mechanical energies generated during repeated compression/decompression cycles while recording the associated P,V- diagrams.

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Sex determination is a fundamental process for organisms. There are two mechanisms for sex determination; genotypic sex determination and environmental sex determination. We, human beings, apply the environmental sex determination for the benefits of aquaculture production in some cases, but on the other hand, anthropogenic climate change, global warming, causes the changes of biomass and/or biodiversity which decrease the fishery production in the sea. In this paper, this bilateral character of the effect of heat and temperature on the sex determination in marine organisms is described and provided an explanation.

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