Improving a technology for treating pig iron outside the furnace with magnesium

Institute of Ferrous Metallurgy. Translated from Metallurg, No. 4, p. 24, April, 1989.     

Life Calculations for Header – PGV-1000 Steam Generator Connector Weld Joints under NPP Service Conditions

The procedure for calculating the life of header – steam generator connector weld joints is proposed. It allows for running out the material plasticity reserve upon static cyclic elastoplastic loading as well as operating conditions, local stress concentrations, and residual stresses after welding.     

Calculation of a three-dimensional flow of a viscous incompressible liquid in the neighborhood of a shallow well on a flat surface

A three-dimensional flow in the neighborhood of a shallow well on a plane was simulated numerically on the basis of a solution of the Reynolds equations written in curvilinear nonorthogonal coordinates and closed by a two-parametric dissipative model of turbulence.The work has been financed by the Russian Basic Research Foundation (Grant No. 94-02-04092 a).Civil Aviation Academy, St. Petersburg, Russia. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 67, Nos. 5–6, pp. 373–378, November–December, 1994.     

Creep and stress-rupture strength of rolled sheet and welded joints of niobium alloy of the system Nb-W-Mo-Zr at high temperatures

High-temperature strength characteristics of rolled sheet, welded joints, and weld metal of niobium alloy 5VMTs of the system Nb-W-Mo-Zr at 1520–2020 K and stresses comprising 0.4–1.0 of the material ultimate strength are given. It is shown that welded joints and cast weld metal under high-temperature prolonged loading conditions are the same as the basic metal, and in a number of cases they surpass it in high-temperature strength characteristics. Empirical dependences are obtained connecting the short-term material strength with its creep resistance characteristics and stress-rupture strength at temperatures above the start of dynamic recrystallization.Translated from Problemy Prochnosti, No. 12, pp. 24–32, December, 1993.     

Distinctive Features of Minimization of a Risk Functional in Mass Data Sets

A statistical learning model is considered within the framework of the theory of uniform convergence of frequencies of errors in the case where the convergence is violated as a result of increasing the informativeness of training examples. Drawbacks of nonconstructive refinements of Vapnik-Chervonenkis estimates based on an assumption on the distribution law of violations are shown. A new approach to obtaining constructive estimates for mass data sets is proposed.     

Utilization of wastes of refractory production in plasma plants

The experience of reprocessing of dusty wastes in centrifugal plasma plants is described. Theoretical calculations by means of a mathematical model are given.Translated from Ogneupory, No. 3, pp. 16–17, March, 1994.     

Differential–Algebraic Equations and Dynamic Systems on Manifolds

The authors consider current problems of the modern theory of dynamic systems on manifolds, which are actively developing. A brief review of such trends in the theory of dynamic systems is given. The results of the algebra of dual numbers, quaternionic algebras, biquaternions (dual quaternions), and their application to the analysis of infinitesimal neighborhoods and infinitesimal deformations of manifolds (schemes) are presented. The theory of differential–algebraic equations over the field of real numbers and their dynamics, as well as elements of trajectory optimization of respective dynamic systems, are outlined. On the basis of connection in bundles, the theory of differential–algebraic equations is extended to algebraic manifolds and schemes over arbitrary fields and schemes, respectively.