Parametric Study of the Noise from Vortex Rings with Various Diameters

A technique for studying the aeroacoustic parameters of vortex rings with various diameters in an anechoic chamber is developed. The motion trajectories of vortex rings produced by a piston generator with nozzles with various exit diameters are studied. Spectral analysis of the noise of vortex rings for various distances from nozzles with various diameters is carried out. For the first time, the dependences of the fundamental radiation frequency on the time of a ring’s motion are obtained in dimensionless form. The data on noise from turbulent vortex rings confirm the conclusion that sound from rings with different diameters and velocities is emitted by the same mechanism.     

Formation and Nature of Microheterogeneous Catalysts Based on Palladium Complexes

The mechanism of the formation and the nature of microheterogeneous catalysts for hydrogenation are discussed using acetylacetonate complexes of palladium with phosphine ligands as an example. Polynuclear palladium complexes with phosphide and phosphinidene ligands are obtained, and their role in the formation of hydrogenation catalysts is found. As distinct from phosphide complexes, amide complexes of palladium are unstable in a hydrogen atmosphere and undergo reduction to form highly dispersed palladium black.     

Synthesis and three-dimensional structures of substituted 4-silyl-4-piperidols

1,2 5-Trimethyl-4-(methyldiphenylsilyl)- and 4-(dimethylphenyl)silyl-4-piperidols were obtained. The isomers of these piperidols of the series, which exist in the chair conformation, have all of their substituents, except the hydroxyl group, equatorially oriented. The isomers of the series exist in solution in the form of an equilibrium mixture of chair and boat conformations, and all of the substituents, except the silyl grouping, are equatorially oriented in the chair conformation.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 502–505, April, 1976.     

Exchange equilibrium in the H-sulfocationite KU-2 × 8-phenylalanine-histidine system

The equilibrium properties of the joint sorption of phenylalanine and histidine on KU-2 × 8 sulfocationite from mixed solution were studied. The effect of the ratio between the concentrations of the amino acids in the solution on their sorption characteristics was reveled. The coefficients of separation and distribution of the amino acids between the sorbent and solution phases were determined.     

Synthesis of new derivatives of D 3-trishomocubane

Russian Journal of Organic Chemistry -     

3-Methyl-9-benzylidene-2-azafluorene and its analogs

The possibility of obtaining 3-methyl-2-azafluorene by dehydrocyclization of 2,5-dimethyl-4-phenylpyridine at 500–750° in the absence of a catalyst was examined. This azafluorene was condensed with aromatic aldehydes. Several transformations of the geometrical isomers of 3-methyl-9-benzylidene-2-azafluorene and its analogs were studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1398–1402, October, 1971.