Resistance of composite flywheel rim to radial tensile stresses from centrifugal forces based on results of pure bending of a rim segment

A method is proposed for evaluating the resistance of a flywheel rim to radial stresses in free rotation. The method is based on loading a rim segment in pure bending and calculating the limiting moment and the corresponding limiting angular velocity. Applicability of the method is substantiated theoretically by investigating the similarity of the radial stress diagrams in rotation and pure bending. The method is verified experimentally for the strained state of a rim segment in pure bending.Translated from Mekhanika Kompozitnykh Materialov, Vol. 29, No. 4, pp. 521–526, July–August, 1993.     

Microscopic theory of vitrification of metallic solutions

A Green's function technique is developed for describing compositional ordering and vitrification of solid solutions with arbitrary composition. It is shown that the proposed approach is related with the standard theory of ordering of regular solid solutions. Peculiarities of the diagrammatic technique are studied. Explicit expressions are derived for the spectrum of solitary excitations, which are responsible for the ordering. Equations are derived for determining the temperature-concentration dependences of the compositional order parameter, the vitrification parameter, and the chemical potential.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 60–65, May, 1991.     

High performance liquid chromatography as a tool in the definition of abnormalities in monoamine and tryptophan metabolites in cerebrospinal fluid from patients with neurological disorders

In this study we report the levels of 3-methoxy-4-hydroxyphenylglycol, 3,4-dihydroxyphenylacetic acid, homovallinic acid, tryptophan, 5-hydroxyindole-3-acetic acid and serotonin in lumbar cerebrospinal fluid (CSF) from patients with multiple sclerosis, cerebrovascular disease and muscular tension headache the later, as healthy controls. The separation of these substances was performed on a reversed phase column by ion pair high performance liquid chromatography and detection was made by a glassy carbon electrode set at +900 mV vs Ag+/AgCl. The whole separation was achieved within 25 min. Concentrations of all substances (10-1000 pmole/L) were linearly proportional to areas obtained. The system is sensitive, stable and reproducible. The significance of CSF levels of these metabolites from patients groups compared with healthy controls are discussed.     

The application of the Mössbauer spectroscopy for the study of the contaminants in the double circuit water heat-carrier nuclear power plant

The iron containing corrosion products from water heat-carrier and deposits of the second circuit of the nuclear power plant were investigated by means of absorption Mössbauer spectroscopy. The nonstoichiometric magnetite and paramagnetic (superparamagnetic) iron oxide particles were found to be the main corrosion products. The fraction of the magnetically ordered phase varied in the range 0–100% depending on the location in the second circuit.     

Features of evolution of the substructure in the creep of dispersion-hardened nickel

A study is made of the laws governing high-temperature creep and the evolution of the substructure in dispersion-hardened alloy Ni — 3 vol. % HfO₂ during its free annealing and creep. The polygonized substructure was formed in the alloy prior to annealing. An analysis is made of structural transformations at different structural levels and the mechanism of high-temperature creep in the alloy. Institute of the Physics of Strength and Materials Science, Siberian Branch of the Russian Academy of Sciences. All-Republic Engineering-Technical Center, Siberian Branch of the Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 83–89, March, 1998.     

Isomorphism of the Baumslag-Solitar groups

Necessary and sufficient conditions for the isomorphism of two groups, each defined by a single relation of the type a^–1b^ma=bⁿ, are obtained.Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 43, No. 12, pp. 1684–1686, December, 1991.