Geometrical theory of diffraction in the scattering of harmonic elastic waves by smooth convex cavities

Institute of Mechanics, Academy of Sciences of the Ukrainian SSSR, Kiev. Translated from Prikladnaya Mekhanika, Vol. 27, No. 2, pp. 26–35, February, 1991.     

Spectral composition of light scattered in fluid flow around a rotating disk

Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 3, pp. 164–169, May–June, 1991.     

A one-phase Stefan problem in a layer of semitransparent medium

A numerical investigation of a one-phase Stefan problem with various boundary conditions in a layer of semitransparent medium is conducted. The significant influence of the optical properties of the medium and the illuminated surface on the generation of temperature fields and radiation flow densities has been demonstrated. Superheating of the specimen near the illuminated surface at the instant of the phase transition has been recorded. The article was translated by L. Vertgeim.     

Scaled-boundary method in electroelasticity of thin plates

The paper discusses the scaled-boundary method as applied to electroelastic problems. As an example, the stress-intensity factor is calculated for a thin rectangular piezoelectric plate with an edge crack __________ Translated from Prikladnaya Mekhanika, Vol. 42, No. 7, pp. 124–134, July 2006.     

Synthesis and search for compounds with hemostatic activity in the series of 4-(het)aryl-4-oxobut-2-enoic acid derivatives

New 4-aryl-2-(4-arylamino)-1-(piperazin-1-yl)but-2-ene-1,4-diones and 2-{[2-(3-R-adamantan-1-yl)-2-oxoethylidene]hydrazinyl}-4-(het)aryl-4-oxobut-2-enoic acids were synthesized and used to obtain water-soluble compounds. Their influence on the blood coagulation system was studied, which revealed compounds with a high hemostatic activity and a low acute toxicity. A relationship between structure and pharmacological effect of the synthesized compounds was established.     

Unsteady Radiative–Convective Heat Transfer in a Flow Emitting‐Absorbing and Scattering Medium around an Ablating Plate

A conjugate problem of radiative–convective heat transfer in a turbulent hightemperature gasdisperse flow around a thermally thin ablating plate is considered. The plate experiences intense radiative heating by an external source, which is a blackbody. The temperature fields and the distributions of heat fluxes along the plate under unsteady conditions are calculated. The data gained make it possible to examine the effect of the Stark number and phasetransition heat in the plate material on the time evolution of the thermal state of the boundarylayer medium and the plate itself being heated by a hightemperature radiation source.     

Numerical modeling of the single-phase Stefan problem in a layer with transparent and semitransparent boundaries

Numerical modeling of the single-phase Stefan problem in a semitransparent layer with transparent, nonabsorbing, and partially radiation-absorbing boundaries is performed. It is shown that at low temperatures of the medium, convection is a determining factor on the boundary of the irradiated sample, and at high temperatures, radiation is predominant. The absence of absorption on the boundaries of the layer leads to acceleration of the heating of the plate and considerable deceleration of melting processes. __________ Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 47, No. 3, pp. 84–91, May–June, 2006.     

Heat exchange between a selectively emitting liquid and a laminar gas flow in the presence of an external source of radiation

An investigation is conducted in the solution of a number of practical problems of the radiative and combined heat exchange in nonuniform systems having widely different physical properties. The processes of thermal interaction between the ocean and the atmosphere have been treated in the paper [1], the effect of thermal radiation on the melting and solidification of semitransparent crystals has been investigated in [2], the flow of a selectively emitting gas around the lateral surface of an object evaporating under the action of radiative heating has been discussed in [3], and heat transfer from a jet to the molten mass of glass in a glassmaking furnace tank has been investigated in [4]. The radiative and combined heat exchange between a selectively emitting liquid and a transparent heat-conducting laminar gas flow in the case of a specified external thermal radiation field is discussed in this paper. The energy conservation equations are set up taking into account the heat transfer by radiation, convection, and molecular thermal conduction. A differential approximation is used in calculating the values of the radiation fluxes. A system of fundamental computational equations is solved by the method of finite differences and iterations and by the Runge-Kutta method. The results of the calculations are presented in the form of graphs.Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 3, pp. 116–122, May–June, 1976.     

Kinetics of the thermal decomposition of dinitramide

The kinetic regularities of the thermal decomposition of dinitramide in aqueous solutions of HNO₃, in anhydrous acetic acid, and in several other organic solvents were studied. The rate of the decomposition of dinitramide in aqueous HNO₃ is determined by the decomposition of mixed anhydride of dinitramide and nitric acid (N₄O₆) formed in the solution in the reversible reaction. The decomposition of the anhydride is a reason for an increase in the decomposition rates of dinitramide in solutions of HNO₃ as compared to those in solutions in H₂SO₄ and the self-acceleration of the process in concentrated aqueous solutions of dinitramide. The increase in the decomposition rate of nondissociated dinitramide compared to the decomposition rate of the N(NO₂)₂ ⁻ anion is explained by a decrease in the order of the N−NO₂ bond. The increase in the rate constant of the decomposition of the protonated form of dinitramide compared to the corresponding value for neutral molecules is due to the dehydration mechanism of the reaction. For Part 1, see Ref. 1. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 41–47, January, 1998.     

Deformation of liquid line with the collision of jets

With the study of the collision of metallic plates accelerated by an explosion, investigation of plastic deformations in the collision zone is of great importance. In [1] a method is expounded for investigations of deformation with explosion welding under conditions of wave formation; the method consists of the pressing of a thin wire into the metallic plate. With collision of the plates, the flowing metal carries the wire with it; the change in the form of the latter makes it possible to evaluate the character of the plastic deformation in the collision zone. From an investigation of the deformation of the wires, such important characteristics as the viscosity of the metals can be found. The method set forth in [1] is one of the few means of investigating the deformation of metals with high-speed collisions. The difficulties in the investigation are bound up with the small times of the process and with the high pressures, developing with an explosion and demolishing the experimental unit. In [1], from an analysis of viscous flow during the collision of plates, a dependence of the shift on the distance to the interface between the materials, described by a parabola, is derived. It is noted that, near the interface, the theoretical and experimental results differ considerably. It is important to make an attempt at a theoretical analysis of the wire deformation if, with the collision of metallic plates, a jet is formed and the interface between the materials is even. In this case, the flow differs strongly from the flow under conditions of wave formation [2], and near the interface the flow cannot be described by a parabolic dependence; this dependence will probably be exponential. To describe flow with the formation of a jet, in [3] a model of an ideal liquid is employed. Since the analysis of a collision between viscous jets with a free boundary is bound up with serious difficulties, in the first approximation it is advisable to consider the deformation of the liquid line with the deformation of ideal jets.Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 6, pp. 65–71, November–December, 1977.The author wishes to express his thanks to N. S. Kozin and V. V. Efremov for a number of valuable observations with an evaluation of the work, and N. M. Maksimova for her aid in making the numerical calculation.