Reduction of the error of hydrophone calibration with respect to the field in a hydroacoustic tank by the reciprocity method

A hydrophone calibration procedure that considerably reduces the error caused by the acoustic field distortions in a hydroacoustic tank is proposed. The procedure is based on the definition of the reduced electric transfer impedances of transducers (i.e., the electric transfer impedances reduced to the spherical wave propagation law) and consists in measuring the electric transfer impedances for different distances between hydroacoustic transducers. The sensitivity of the hydrophone under calibration is calculated from the far-field values of the reduced electric transfer impedances. The latter are determined using a mathematical model of the hydrophone in the form of a system that contains a point sensing element and a finite number of point sources of acoustic signals (point reflectors). A method of determining the number and coordinates of the point reflectors from the analysis of the acoustic “images” of the hydrophone’s reflecting surface is proposed. The measuring technique, the algorithms of mathematical processing, and the results of experimental studies are considered. A comparative analysis of the results of the hydrophone calibration with respect to the field by the reciprocity method is performed for the cases of using the conventional technique and the proposed method.     

Chemical Aspects of Electrocatalytic Reduction of Carbonyl Compounds. Aldehydes

Russian Journal of Organic Chemistry -     

Conductivity of Bi<Subscript>2</Subscript>O<Subscript>3</Subscript>-NiO composites

The conductivity and transport number of oxygen ions of Bi₂O₃-(10, 30, 50) vol % NiO composites are measured using the four-probe and coulomb-volumetric methods at various temperatures. It is shown that the Bi₂O₃-50 vol % NiO composite exhibits a high mixed ionic-electronic conductivity in the temperature range from 730 to 800°C.     

Quantum-chemical study of the reaction of pent-4-en-2-yn-1-ol with copper,zinc, and nickel sulfides

Complexes of metal sulfides MS (M = Cu, Zn, Ni) with pent-4-en-2-yn-1-ol modeling dimethyl-(isopropenylethynyl)carbinol, a potent floating agent for benefication of nonferrous metal ores, were calculated by the B3LYP density functional theory method with the 6–31G** basis set. The adsorption mechanisms of vinylacetylenic and aliphatic alcohols were shown to vary depending on the nature of the metal sulfide. This fact can be taken into account on the flotation of mixed ores for selective metal extraction.     

Effect of Complexing Agent on the Reactivity of Organomagnesium Compounds in Toluene

Russian Journal of Organic Chemistry -     

Thermophoresis-Assisted Microscale Magnus Effect in Optical Traps

The Magnus effect, commonly observed on the macroscale, has been considered to be negligible at the microfluidic limit. However, the thermophoretic effect at the microscale leads to a strong lift force that acts on the optically trapped and heated microparticles rotating in a liquid flow. This thermophoresis-assisted Magnus effect is experimentally observed and explained through the inhomogeneity of temperature distribution in the flow around the absorbing microparticles rotated by magnetic forces within the limit of ultralow Reynolds numbers.