A nonlinear mechanism of the energy transfer by a perturbation front in the course of local high-energy loading

The features of perturbation propagation in a copper crystal grain under local high-energy loading conditions were studied. The process was studied by method of molecular dynamics using multiparticle model potentials calculated within the framework of the embedded atom approximation. It is shown that a nonlinear solitary pulse is formed in the crystal, which is capable (in contrast to the case of a linear perturbation) of transferring the energy at a high density over relatively large distances. The energy transfer range depends both on the area and on the rate of local loading.     

Combustion of bulk density powder mixtures in a coflow of nitrogen gas: 3. The Ti-(Ti + 0.5C) layered system

Explored is the filtration combustion in Ti-(Ti + 0.5C) layered powder systems in a coflow of nitrogen gas. The presence/absence of nitrogen coflow through the layered system was found to drastically affect the character of wave propagation and structure/properties of product. The obtained data can be regarded as a basis for fabrication of new layered and composite materials in the mode of dynamic filtration combustion.      

Calculation of characteristics of heat and mass transfer during destruction of thermoprotective material

The process of nonstationary heat and mass transfer in a carbon-epoxy composite under the action of a high-enthalpy flow is analyzed numerically within the framework of the mathematical model of a reacting medium. Analytical solutions have been obtained for the value of mass entrainment from the material surface, depending on the entrainment velocity at the expense of pyrolysis of the carbon-epoxy composite. The solutions obtained are in agreement with the results of numerical integration for constant and variable parameters of retardation. The possibility of simplifying the boundary conditions is analyzed, and recommendations for performing serial calculations are offered.Research Institute of Applied Mathematics and Mechanics, Tomsk 634050. Translated from Fizika Goreniya i Vzryva, Vol. 30, No. 4, pp. 76–84, July–August, 1994.     

VBÉR-300 reactor system and power-generating units for regional nuclear power production

The basic design solutions and characteristics of the VBéR-300 reactor system for the power-generating units of 150–300 MW(e) nuclear power plants and regional nuclear heat-and-electricity plants are described. The reactor system implemented as a unit is based on the technologies and solutions used for marine nuclear power systems, which have been corroborated by experience in operating nuclear-powered icebreakers. The technical-economic advantages of floating power-generating units are substantiated. __________ Translated from Atomnaya énergiya, Vol. 102, No. 1, pp. 35–39, January, 2007.     

Analysis of the Thermal Explosion in Systems Porous Reagent–Active Gas–Solid Product

The specific features of dynamics of the thermal explosion in systems porous reagent–active gas–solid product under conditions where the heattransfer and masstransfer regions are separated from the ambient medium are considered. In addition to the competition of heat release and heat removal, the process of initiation of exothermal chemical interaction in these systems under normal pressures depends significantly on conditions of filtration transport of the gaseous reagent. The induction and postinduction periods of the thermal explosion are studied. The theoretical analysis of thermalexplosion issues is supplemented by an experimental study of the process for the porous titanium–nitrogen–titanium nitride system.     

Optimal Control of Longitudinal Motion of an Elastic Rod Using Boundary Forces

Journal of Computer and Systems Sciences International - This study is devoted to the issues of controllability and optimization of oscillatory motions of dynamic systems with distributed...     

Portable instruments for multiparameter magnetic evaluation of material structures

The principles of operation and capabilities of portable computerized testing facilities of the MMT and SIMTEST series, which are intended for multiparameter magnetic evaluation of the structure of ferromagnetic articles of different dimensions, are described.     

Reachability analysis in T-invariant-less Petri nets

An algorithm for reachability analysis in place/transition Petri nets having no transition invariants (T-invariants) is proposed. Given a Petri net with initial and target markings, a so-called complemented Petri net is created first that consists of the given Petri net and an additional complementary transition. Thereby, the reachability task is reduced to computation and investigation of those minimal-support and linearly combined T-invariants of the complemented Petri net, in which the complementary transition fires only once. Then, for each T-invariant with a single firing of the complementary transition, the algorithm will try to create a reachability path from the given initial marking to the target marking.     

Cellular filtration combustion of porous layers

The cellular filtration combustion of porous energetic compositions that interact with an active gas reagent and form condensed reaction products is studied for titanium powder combustion as an example. A simple and visually accessible quasi-experimental analysis of the nonlinear propagation of the combustion front with adjustable filtration transport of gas is proposed. Under conditions of a deficiency of the gas reagent and instability, the flat front of filtration combustion is divided into isolated cells of exothermic chemical reaction propagating in a pulsating mode. The results obtained are interpreted within a model of thermal filtration stability of the filtration combustion front.     

Transformation of the thermal regimes of exothermic reactions in the case of harmonic perturbations of the velocity and temperature of reagents at the entrance of the adiabatic reactor

The physical concepts and the results of the thermal theory of combustion are used as a basis for the qualitative analysis and mathematical simulation of transformation of stationary temperature distributions along the length of an adiabatic reactor in the case of periodic perturbations of the velocity of the reagent in the reactor and its temperature at the entrance of the reactor. It is established that, with certain values of the amplitude and frequency of harmonic perturbations of the velocity of the reagent, it is possible to improve the thermal stability of the process (increase the pre-explosion heating).