13,409 research outputs found

    Development of the heat and mass transfer model for the study of the temperature traces water droplets in a flame

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    The heat and mass transfer model is developed with using Ansys Fluent. The typical temperature of gases in the trace of water droplets is determined (initial temperature of gases 1170 К). Several types for the location of water droplets are studied: two successive water droplets; two parallel water droplets; five water droplets in checkerboard order. The hypothesis about gas temperature reduction in the trace of a moving liquid is confirmed

    Coulomb correlation effects in zinc monochalcogenides

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    Electronic structure and band characteristics for zinc monochalcogenides with zinc-blende- and wurtzite-type structures are studied by first-principles density-functional-theory calculations with different approximations. It is shown that the local-density approximation underestimates the band gap and energy splitting between the states at the top of the valence band, misplaces the energy levels of the Zn-3d states, and overestimates the crystal-field-splitting energy. Regardless of the structure type considered, the spin-orbit-coupling energy is found to be overestimated for ZnO and underestimated for ZnS with wurtzite-type structure, and more or less correct for ZnSe and ZnTe with zinc-blende-type structure. The order of the states at the top of the valence band is found to be anomalous for ZnO in both zinc-blende- and wurtzite-type structure, but is normal for the other zinc monochalcogenides considered. It is shown that the Zn-3d electrons and their interference with the O-2p electrons are responsible for the anomalous order. The typical errors in the calculated band gaps and related parameters for ZnO originate from strong Coulomb correlations, which are found to be highly significant for this compound. The LDA+U approach is by and large found to correct the strong correlation of the Zn-3d electrons, and thus to improve the agreement with the experimentally established location of the Zn-3d levels compared with that derived from pure LDA calculations

    Performance of Hamamatsu 64-anode photomultipliers for use with wavelength--shifting optical fibres

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    Hamamatsu R5900-00-M64 and R7600-00-M64 photomultiplier tubes will be used with wavelength--shifting optical fibres to read out scintillator strips in the MINOS near detector. We report on measurements of the gain, efficiency, linearity, crosstalk, and dark noise of 232 of these PMTs, of which 219 met MINOS requirements.Comment: 15 pages, 12 figures. Accepted by Nucl. Inst. Meth.

    Evaluation of Rhizopus oligosporus Yeast Supplementation on Growth Performance and Nutrient Digestibility in Nursery Pigs

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    The growth and performance of 24 nursery pigs fed a fungal cultivation of Rhizopus oligosporus (RO) was evaluated in a 28-day feeding and digestibility study. Nursery pigs average start weight of 5.62 ± 0.35 kg were provided ad libitum access to a corn-soybean diets containing three levels of RO, 0, 10, or 20%. Diets were formulated to be isocaloric and isolysinic, and contained the digestibility marker titanium dioxide. There was no difference in pig performance based on dietary inclusion of RO fungus. However, total tract DE was improved when feeding RO. Altogether, these data indicate that Rhizopus oligosporus cultivated on distillers stillage and bioproducts can be used in nursery swine diets with no negative effects on performance
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