Problems of the theory of deformation of polymeric materials under complex loading

Research on problems of the theory of deformation of polymeric materials under complex loading based on a synthesis of creep theories and the local strains theory is reviewed.Presented at the 2nd All-Union Conference on Polymer Mechanics, Riga, November 10–12, 1971.M. V. Lomonosov Moscow State University. Institute of Polymer Mechanics, Academy of Sciences of the Latvian SSR, Riga. Translated from Mekhanika Polimerov, No. 3, pp. 434–443, May–June, 1972.     

Physical source realization of complex source pulsed beams

Complex source pulsed beams (CSPB) are exact wave-packet solutions of the time-dependent wave equation that are modeled mathematically in terms of radiation from a pulsed point source located at a complex space-time coordinate. In the present paper, the physical source realization of the CSPB is explored. This is done in the framework of the acoustic field, as a concrete physical example, but a similar analysis can be applied for electromagnetic CSPB. The physical realization of the CSPB is addressed by deriving exact expressions for the acoustic source distribution in the real coordinate space that generates the CSPB, and by exploring the power and energy flux near these sources. The exact source distribution is of finite support. Special emphasis is placed on deriving simplified source functions and parametrization for the special case where the CSPB are well collimated.     

Stress Concentration Near Stiff Cylindrical Inclusions under Anti-Plane Shear Loading

Doklady Physics - Analytical solutions for the problems of stress concentration near cylindrical inclusion with circular or elliptical cross section under the anti-plane shear loading are...     

Specific Features of Thermal Degradation of Polypropylene in the Presence of Magnesium Hydroxide

Specific features of thermal oxidative degradation of polypropylene and its composite with Mg(OH)₂ were studied by pyrolytic gas chromatography-mass spectrometry and thermal gravimetric analysis.     

Application of the aperture synthesis technique in optical interference microscopy

A method of integrated computational processing of series of microscopic images obtained at different angles of object illumination is proposed. Numerical simulation is performed based on the rigorous solution of the vector problem of electromagnetic scattering at various objects. The possibilities of increasing the effective resolving power of microscopes by using this method are studied.     

Macrokinetic model of pyrolysis of carbonaceous feedstock in a tubular reactor

A macrokinetic model of pyrolysis of carbonaceous feedstock in a tubular reactor was proposed. It was shown that, under unsteady-state conditions (at oscillating temperature of feedstock heating), higher conversions can be reached in comparison with steady-state conditions, which agrees with experimental data on flash pyrolysis of biomass in a tubular reactor during heating–cooling cycles.     

Heterogeneous and homogeneous hydrogenation of styrene and stilbene chromium tricarbonyl complexes

Heterogeneous hydrogenation of the styrene and stilbene chromium tricarbonyl complexes by molecular hydrogen on skeletal nickel and palladium on carbon as catalysts was studied. As compared to styrene and stilbene, their arene chromium tricarbonyl analogs are hydrogenated considerably more slowly, which is related, most likely, to strong adsorption of the π-complexes on the catalyst surface. For the homogeneous hydrogenation of these complexes using a H₂PtCl₆-SnCl₂-LiBr system, styrene and η⁶-styrene chromium tricarbonyl are reduced with a high rate, whereas stilbene and its chromium tricarbonyl complex are hydrogenated very slowly. A possibility of reduction of the unsaturated arene chromium tricarbonyl complexes by sodium borohydride in the presence of cobalt(II) chloride as a catalyst was shown. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 44–47, January, 2007.