Dry Friction Behavior of Barite-Containing Composites in a Pair with Steel

Refractories and Industrial Ceramics - The article is devoted to the preparation of ecologically clean composites by powder metallurgy and the study of tribological properties. Tribological tests...     

Matrix models of the accuracy in multitool two-support setup

The matrix models describing the processing error in multi-tools arrangements taking into account all components of cutting forces from all tools and the elastic deformations of technological system over all coordinates have been developed. The procedure permitting to form the field of sizes dispersion using the mechanism of two-slide assembly has been developed in order to determine the extremum of size distortion function.     

Oxidative Cycloaddition of Aldoximes with Maleimides using Catalytic Hydroxy(aryl)iodonium Species

A mild catalytic procedure for the efficient oxidative cyclization of aldoximes with maleimides mediated by hypervalent iodine(III) active species has been developed. This catalytic cyclization affords the corresponding pyrrolo‐isoxazole products in generally good yields. The catalytic cycle involves active hydroxy(aryl)iodonium species generated in situ from 2‐iodobenzoic acid as precatalyst and m‐chloroperoxybenzoic acid (m‐CPBA) as terminal oxidant in the presence of trifluoromethanesulfonic acid. The presence of active hydroxy(aryl)iodonium species in this reaction has been confirmed by ESI‐mass spectrometry and ¹H NMR spectroscopy.

     

Production of thin-walled castings by the lost-wax process

Translated from Khimicheskoe i Neftyanoe Mashinostroenie, No. 7, pp. 37–38, July, 1989.     

Mathematical model of the dynamics of nonequilibrium adsorption in a stationary bed

The nonequilibrium dynamics of adsorption in a stationary bed of aluminosilicate adsorbent was mathematically described on the example of dearomatization of the 200–320°C fraction of liquid paraffins. The characteristics obtained indicate the important effect of the initial concentration of adsorbate in the feedstock and the temperature and flow rate of the feedstock on the process diffusion parameters. This effect must be taken into consideration in designing industrial adsorbers. __________ Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 4, pp. 16–18, July–August, 2007.     

Necessary optimality conditions for singular control in one system with distributed parameters

The notion of a control singular with respect to component is introduced and used to propose a new scheme of deriving necessary optimality conditions of the control singular in classical terms with respect to component. New multi-point necessary optimality conditions are obtained for controls singular with respect to component in the Goursat-Darboux systems.     

Increasing the Productivity of Multitool Machining on Automated Lathes by Optimizing the Machining Plan

Russian Engineering Research - A method is developed for optimizing surface machining plans on the basis of a mathematical model in which the influence of the diameter in each pass on the...     

Entwicklung einer Projektierungstheorie für die Mehrwerkzeugbearbeitung mit den Möglichkeiten der modernen CNC-Werkzeugmaschinen

Forschung im Ingenieurwesen - Die Projektierung der Mehrwerkzeugbearbeitung auf den CNC-Werkzeugmaschinen beruht im Wesentlichen auf der Intuition des Einrichters. Oft vermeiden Planer solche...     

Investigation and Computer Modeling of Separation of Gas Mixtures

Theoretical Foundations of Chemical Engineering - The technology of separation of gas mixtures was reviewed and analyzed. The adsorption isotherms and breakthrough curves were studied for the...     

Hypoiodite‐Mediated Catalytic Cyclopropanation of Alkenes with Malononitrile

An efficient synthetic procedure for dicyano‐cyclopropanation of alkenes using catalytic amounts of molecular iodine as a precatalyst and tert‐butyl hydroperoxide (TBHP) as a terminal oxidant under mild conditions has been developed. This catalytic reaction works especially well for the aryl‐substituted double bond affording products of cyclopropanation in high yields. A catalytic cycle based on the generated in situ hypoiodite species has been proposed.