Convective heat-transfer enhancement by electric fields

A general problem is formulated of electroconvective heat transfer and the problems of this kind are classified according to motive force types and to nonuniformity of electrophysical parameters. Typical cases of nonuniformities are considered, namely, thermal, mechanical and those due to the electric field itself. A qualitative theory is developed covering all the flow patterns which correlates experimental data on electroconvective heat transfer in homogeneous and disperse media and on corona discharge in gases. Experimental data agree with theoretical predictions.     

On the nature of metal passivation during cathode depolarization by oxygen dissolved in an electrolyte

A hypothesis is suggested and grounded according to which a metal is passivated due to the formation of an oxide whose composition corresponds to the maximum oxygen concentration in the homogeneity area of this oxide on the metal surface. In this case, the thermodynamic probability of a corrosion process becomes close to zero. Experimental data are obtained on the dependence of the thermodynamic activity of carbon on its concentration in the homogeneity areas of cubic vanadium and titanium carbides. The dependences derived from these data are assumed to be also valid for metal oxides.     

Plastic deformation nonuniformity and localization during metal forming

The nonuniformity of deformation of metallic materials during metal forming, the causes of its appearance, its mechanisms, the effect of the deformation nonuniformity on the limiting strain of a billet, the loss of stability and its causes during plastic deformation are discussed. Experimental results are given for the loss of stability during longitudinal flat rolling. These results are important for understanding metal flowing under various loading conditions.     

Molecular beam epitaxy of GaPN,GaPAsN, and InGaPN nitride solid solutions

Experimental samples of semiconductor heterostructures with GaP_1?x N _x layers and _{In1?x ? y} GaP _y N _x and GaP _y N _x As_{1 ? x ? y} quantum wells are synthesized by molecular beam epitaxy on GaP (001) substrates. The structural properties of the samples are investigated by X-ray diffraction and the molar fraction x of nitrogen in the GaP_{1 ? x} N _x layers is determined. To compare the structural and optical properties of the samples, the photoluminescence of epitaxial GaP_{1 ? x} N _x layers and heterostructures with InGaPN and GaPAsN quantum wells with GaPN barriers is studied. The photoluminescence and X-ray diffraction data on the GaP_1?x N _x samples are compared with parameters calculated within the band anticrossing model. Based on the experimental and calculated data, it is concluded that the hybridization parameter is not constant and depends on the molar fraction of nitrogen.     

Use of converter slags in blast-furnace smelting

Donetsk Scientific-Research Institute of Ferrous Metallurgy (DonNIIchermet). Enakievo Metallurgical Plant. Translated from Metallurg, No. 12, pp. 37–38, December, 1990     

Heat transfer in emulsions of poor conductors under electric field

The results of investigation are presented of hydrodynamic and heat-transfer processes in dielectric emulsions with disperse phase of higher conductivity under electric field. The dependence of the heat-transfer coefficient on the field strength, temperature driving force, temperature and concentration of emulsions is shown. The accumulation mechanism of space charge which causes EHD-distribution of the field is analysed. A one-dimensional problem is considered whose solution shows charge distribution in the field of a plane capacitor and reveals the presence of similarity region of heat-transfer processes in case of emulsions with high concentrations. The results on heat transfer under the electric field effect are treated in terms of similarity numbers.