Energy characteristics of a solid-state laser pumped by emission from a cumulative jet

St. Petersburg Mechanical Institute. Translated from Inzhenerno-fizicheskii Zhurnal, Vol. 62, No. 2, pp. 261–266, February, 1992.     

Determination of the coefficients of reduction of fatigue strength of structural elements with stress raisers in the range of limited life

The article considers the possibility of using in practice the Socie-Morrow-Chen model for calculating the life of structural elements with stress raisers. It shows that there is good agreement of the theoretical estimates with the results of the experimental determination of the number of cycles corresponding to the initial stage of development of damage, N_L. To develop the model the article suggests a procedure of taking into account the influence of the local mean stress of the strain cycle on N_L, based on the use of a single dependence of the strain amplitude on the number of cycles up to the appearance of a crack with any coefficients of load cycle asymmetry R that takes into account the influence of R solely on the crack growth rate in the zone of stress concentration. The numerical calculations make it possible to establish the effective coefficients of reduction of fatigue strength which increase with an increase of the cyclic load base.Translated from Problemy Prochnosti, No. 11, pp. 3–12, November, 1992.     

Study of Physical and Mechanical Properties of Nickel-Beryllium Alloy 97NL-VI Cold-Rolled Strip

Metallurgist - The structure of specimens at different stages of thin strip fabrication (from ingot to cold-rolled strip) is investigated. Alloy 97NL-VI strip specimen properties are studied,...     

Effect of elemental composition on phase formation during milling of multicomponent equiatomic mixtures

Using mechanochemical synthesis through milling of equiatomic multicomponent mixtures of Cr, Fe, Co, Ni, Al, Ti, Mo, and Nb metals in various combinations, we have synthesized powder alloys with different phase compositions: amorphous phase (AP), AP + BCC phase, AP + BCC phase + MO, and FCC + BCC phases. The FCC phase has been shown to be a Ni-based solid solution. The presence of aluminum in a starting mixture helps to stabilize the BCC phase owing to the formation of a disordered B2 phase. Al dissolves in both the BCC and FCC solid solutions, increasing their lattice parameters. In Al-free starting mixtures, Cr is responsible for the formation of the BCC solid solution. The formation of an AP during milling of multicomponent mixtures is favored by the presence of transition metals with a large atomic radius: Ti, Mo, and Nb.     

Decomposition method for a class of transport-type problems with a quadratic objective function

A class of transport problems with a quadratic criterion without any restrictions on the sign of unknown variables is considered. An iterative algorithm based on the consecutive modification of the coefficients of the objective function is used. The problem is reduced to successively solving pairs of problems from various groups of restrictions. These problems have one connecting variable and are solved analytically by the method of Lagrange multipliers. If the negative components appear in the course of solving them, the problem with one or several restrictions from one group and all restrictions from the other group is considered. These problems can also be easily solved for large dimensions, and in this way the dimension is reduced.     

Dependence of the optical properties of the 30.5K<Subscript>2</Subscript>O · 8.3Al<Subscript>2</Subscript>O<Subscript>3</Subscript> · 3.6SiO<Subscript>2</Subscript> · 57.6P<Subscript>2</Subscript>O<Subscript>5</Subscript> glass on the trivalent titanium content

An optical material, namely, the potassium aluminosilicophosphate glass activated with trivalent titanium ions, is synthesized and studied. The optimum concentration range (0.2–10.0 wt % Ti₂O₃) that provides the best physical, luminescent, and kinetic properties of glasses is determined. This makes it possible to use the sensitizing properties of Ti³⁺ ions to the greatest extent.Original Russian Text Copyright © 2004 by Fizika i Khimiya Stekla, Batyaev, Leonov.