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The temperature dependency of the thermophysical properties of an alumina-water nanofluid and their effects on laminar forced-convective heat transfer enhancement in nanofluids have been investigated analytically in this study. Exact solutions have been obtained for hydrodynamically and thermally fully developed nanofluid flows in a tube subject to constant heat flux, with and without accounting for the temperature dependency of thermophysical properties. The solutions reveal that the anomalous heat transfer enhancement is possible, irrespective of the account of the temperature dependency of nanofluid thermophysical properties, such that the heat transfer rate exceeds the rate expected from the increase in the nanofluid thermal conductivity. A comparison between the solutions, with and without accounting for the temperature dependency of nanofluid thermophysical properties, indicates that the temperature dependency of thermophysical properties only reflects on the relative magnitude of the Nusselt number and its asymptotic value, and that it does not have any significant influence on the occurrence of anomalous heat transfer enhancement. [ABSTRACT FROM AUTHOR]

Uniform and well-crystallized octahedral NaGd(MoO4)2:Eu3+ microcrystals have been successfully synthesized by a facile one-step hydrothermal synthesis method without involving any templates. The prepared samples were systematically characterized by powder X-ray diffraction, field-emission-scanning electron microscopy, photoluminescence (PL), and photoluminescent excitation spectra. The starting pH value played an important role in the pure-phase formation and uniform morphology of octahedral microcrystals. Detailed proofs indicated that the growth process of NaGd(MoO4)2:Eu3+ microcrystals was dominated by a nucleation-crystallization-oriented attachment mechanism. Furthermore, the luminescent properties of the as-synthesized NaGd(MoO4)2:Eu3+ microcrystals were investigated, demonstrating that the PL intensity was influenced by the different mor- phologies, and the bipyramidal octahedra NaGd(MoO4)2:Eu3+ luminescent microcrystals might be applied as an excellent red comDonent for near-UV white light emitting diodes. [ABSTRACT FROM AUTHOR]

CaSnO3:Eu3+ microcrystals with controlled morphology were prepared by a hydrothermal method followed by further calcining treatment without any template or capping reagents. Reactant concentration and reaction time showed strong effects on the phase formation and morphology of the products. The prepared samples were systematically characterized by powder X-ray diffraction, field-emission scanning electron microscopy, photoluminescence (PL), and photoluminescent excitation spectra. The possible formation mechanism was proposed. Furthermore, PL characterization of CaSnO3:Eu3+ microcrystals was performed and discussed in detail. [ABSTRACT FROM AUTHOR]