Unsteady axisymmetric stagnation flow on a circular cylinder

Unsteady, axisymmetric stagnation flow about a circular cylinderis examined when the far-field flow is a periodic function oftime with a fixed time average and an oscillatory part of prescribedamplitude and frequency. Solutions are computed for arbitraryvalues of the Reynolds number, quantifying the effects of surfacecurvature, and a frequency parameter based on the period ofthe far-field flow. It is found that solutions remain regularand periodic provided that the far-field amplitude lies belowa critical value. Above this value, solutions terminate in afinite-time singularity. The blow-up time is delayed by increasingthe curvature of the surface. These results are corroboratedby asymptotic predictions valid in the limits of small and largeamplitude and frequency. For large Reynolds number, the problemreduces to the two-dimensional stagnation-point flow againsta plane wall studied by previous authors.     

Reaction of 1-arylsulfamido-2-chloroethane with amines

Conclusion The reaction of 1-arylsulfamido-2-chloroethanes with diethylamine and aniline gives 1-arylsulfamido-2-aminoethanes.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 943–946, April, 1987.     

Synthesis of 3,4,4'- and 2',3,4-Triaminodiphenyl Ethers

Procedures were developed for preparing 3,4,4'- and 2',3,4-triaminodiphenyl ethers by the reaction of 4-acetylaminophenol with, respectively, 4-nitro- or 2-nitrochlorobenzene, followed by nitration of the resulting 4-acetylamino-4'- or -2'-nitrodiphenyl ether, hydrolysis of the product, 4-acetylamino-3,4'- or -2',3-dinitrodiphenyl ether, and reduction of 4-amino-3,4'- or -2'-3-dinitrodiphenyl ether.     

The interaction of coordinationally unsaturated 2,9-dimethylphenanthroline cobalt complex with adenine nucleotides

The study of complex formation between adenosine triphosphate (ATP) or adenosine diphosphate (ADP) and coordinationally unsaturated cobalt complex with 2, 9-dimethyl-o-phenanthroline (L) showed the possibility of formation of relatively stable mixed ligand complex CoL·ATP (log=4.45). The latter may be formed under the oxidative phosphorylation conditions in mitochondria. The presence of ATP in the complex provides the specific inhibition of the ATPase active center.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 744–748, April, 1994.     

Identification of impurities accumulated in the extractant in the course of purification of wet-process phosphoric acid with tri-<Emphasis Type="Italic">n</Emphasis>-butyl phosphate

Impurities accumulated in the extractant in the course of operation of the plant for purification of wet-process phosphoric acid, obtained from apatite concentrate, by extraction with tri-n-butyl phosphate are identified by IR and mass spectra.Translated from Zhurnal Prikladnoi Khimii, Vol. 77, No. 9, 2004, pp. 1425–1429.Original Russian Text Copyright © 2004 by Lembrikov, Konyakhina, Volkova, Perov, Kiseleva, Ershova.     

Optimization of Conditions for the HPLC Determination of Synthetic Dyes in Food

The retention of synthetic food dyes on the sorbent Kromasil C18 was studied under the conditions of reversed-phase and ion-pair high-performance liquid chromatography, depending on the concentrations of the ion-pair reagent (tetrabutylammonium dihydrophosphate) and organic solvent (acetonitrile) in the mobile phase and on the concentration and pH of the phosphate buffer solution. The optimum conditions were selected for the separation of ten dyes in the isocratic elution mode within 25 min. A procedure was developed for the determination of synthetic food dyes in foodstuffs; the detection limit was 10–30 g/L.     

Py-methyl-α-metanicotone. Action of benzoyl chloride on py-methyl-α-nicotone

Summary 1-Methyl-3-[4-(N-methylbenzamido)-1-butenyl]-2(1H)-pyridone was prepared by cleavage of the pyrrolidine ring of Py-methyl--nicotone with benzoyl chloride, and hydrolysis of this product gave P_y-methyl--metanicotone.     

Derivatives of Methyl N-[5(6)-(4-Aminophenylsulfanyl)benzimidazol-2-yl]carbamate and Phthalic Anhydrides. Synthesis and Biological Properties

Products of the reactions methyl N-[5(6)-(4-aminophenylsulfanyl)benzimidazol-2-yl]carbamate with phthalic anhydrides, involving the aniline nitrogen atoms, were obtained. Biological properties (embryotoxicity and toxicity) of the products and their mixtures with phase-transfer catalysts were studied. On this basis, new antihelminthic agents were developed.