Anodic behavior of stainless steels in electrochemical synthesis of graphite bisulfate

Anodic-corrosion behavior of a number of chromium-nickel steels in a 80% H₂SO₄ solution was studied in order to replace platinum with less expensive electrodes in electrochemical synthesis of graphite bisulfite and corrosion parameters were determined.     

Extraction of nitric acid by tributyl phosphate solution in <Emphasis Type="Italic">n</Emphasis>-dodecane

Experimental data based on the extraction of nitric acid by 30, 12, and 5 vol % tributyl phosphate (TBP) solutions in n-dodecane were obtained and calculations of equilibrium were performed. It was shown that the values of the formation constants and hydrate numbers of mono-, di-, and half-solvates found for a system containing 100% TBP can be used in performing the calculations. It is also suggested that extraction of half-solvate proceeds with a lower constant of formation and a lower hydrate number when TBP is diluted by n-dodecane half-solvate.     

Mass Spectrometric Analysis of Microcystins from Cyanobacterial Biomass: Optimization of the Sample Preparation Procedure

The sample preparation procedure for determination of microcystins from biomass by the LC–MS method was optimized. Treatment of freeze-dried biomass samples with acetonitrile prior to the main extraction was effectively used for decreasing the amount of protein-like matrix compounds in extracts. Use of acetonitrile–water mixtures during the main ultrasound-assisted extraction allowed increasing the total microcystins amount in the resultant extracts compared to the traditional extraction using 75% methanol.     

Synthesis of basic bismuth(III) oxalate by precipitation from nitrate solutions

Conditions were determined in which basic bismuth oxalate of composition BiC₂O₄(OH) can be obtained by direct precipitation upon addition of oxalic acid from nitrate solutions used in production of bismuth compounds. The composition of the compound was confirmed by X-ray phase and chemical analyses, IR and Raman spectroscopy, and thermogravimetry. Electron microscopy was used to examine the effect of the composition of the reaction medium and temperature on the morphology of the product being obtained. It was shown that β-Bi₂O₃ can be obtained in oxidative thermolysis of basic bismuth oxalate, depending on its morphology.     

Development and validation of the method for the quantitative determination of clotrimazole in medicated films for treatment of otomycosis

Methods have been developed for the quantitative determination of clotrimazole in polymeric medicated films for treatment of patients with otomycosis by the ultraviolet spectrophotometric method according to intrinsic absorption. The validation of the methods in the parameters such as linearity, accuracy, and precision has shown that they can be used to analyze films with clotrimazole.     

Modeling of the catalytic properties of high-temperature surface insulation in a dissociated carbon dioxide — Nitrogen mixture

A model of the heterogeneous catalysis of a dissociated carbon dioxide — nitrogen mixture on high-temperature heat-shield coatings is developed; the model takes into account nonequilibrium adsorption-desorption reactions of nitrogen and oxygen atoms and carbon dioxide molecules and their recombination in the Eley-Rideal reactions. On the basis of a comparison of the calculated heat fluxes in dissociated carbon dioxide with those measured on the VGU-4 plasma generator of the Institute for Problems in Mechanics of the RAS, the parameters of the catalysis model in question are chosen for three modern oxidant-resistant coating materials. The performances of these coatings are compared for the conditions of Mars Miniprobe entry into the Martian atmosphere. Their usability for the entry path considered is shown. Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 1, pp. 106–116, January–February, 2000. The study was carried out with the support of the Russian Foundation for Basic Research (project No. 99-01-00259) and the “Integratisya“ Federal Program (project No. 2.1–414).     

Numerical analysis of the effect of local energy supply on the aerodynamic drag and heat transfer of a spherically blunted body in a supersonic air flow

The effect of local source of energy in a supersonic flow on the aerodynamic drag and heat transfer of a spherically blunted body is studied numerically. Calculations are performed on the basis of the Navier-Stokes equations for a thermally equilibrium model of air. Data on the effect of the intensity and size of the energy source on the wave drag, friction, and heat transfer are obtained. Particular attention is given to studying the effect of drag reduction by means of a focused heat source. The gas-dynamic nature of this effect is studied. The limits of drag reduction are estimated, and optimal conditions of heat supply are determined. Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 41, No. 5, pp. 171–179, September–October, 2000.     

Indoles

A new single stage method is described for the synthesis of 1-substituted tryptamines by boiling alcoholic solutions of various -substituted phenylhydrazines and -halogen carbonyl compounds in neutral medium.For part I, see [7].     

Composite materials on the basis of phenylenecarboxylate framework MOF-5 and calix[4]arenes with various structures

A comparative study of the texture and adsorption characteristics of newly synthesized composite materials based on 1,4-benzenedicarboxylate metal-organic framework MOF-5 and calix[4]arenes with various structures was performed.     

Martensite and hydride transformations in the V-N-H and V-O-H systems

Optical metallography has been applied to vanadium containing traces of oxygen and nitrogen on electrolytic saturation with hydrogen; a martensite phase is formed near room temperature and above (formation controlled by the H/V concentration), and hydrides segregate, which suppress further martensite growth.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 39–42, March, 1990.