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Èçäàòåëü: Áåëàðóñêàÿ íàâóêà, Ìèíñê, Ðåñïóáëèêà Áåëàðóñü
| Èçâåñòèÿ Íàöèîíàëüíîé àêàäåìèè íàóê Áåëàðóñè ÑÅÐÈß ÔÈÇÈÊÎ-ÒÅÕÍÈ×ÅÑÊÈÕ ÍÀÓÊ Èçäàòåëü: Áåëàðóñêàÿ íàâóêà, Ìèíñê, Ðåñïóáëèêà Áåëàðóñü |
Summary: The method of determining porosity in experimental casting was developed to verify the results of computer calculations of regularity of formation of porosity for cutectic type alloys. The series of experiments were conducted to learn the influence of rate of casting cooling, alloy composition, macrostructure type and other factors upon the magnitude and location of porosity. The experimental test showed good coinsideness of the accounted and the real data.
Ustinovich D. F., Filatov S. A.
Investigation on effect exerted by technological factors of high-speed magnetic-abrasive processing on surface layer microhardness. pp. 9--11
Summary: The effect of technological magnetic-abrasive processing parameters on a surface layer microhardness has been the subject of experimental investigation. The determination is made of mathematical relationships between a surface layer micro-hardness value of a hardened steel and technological factors of a high-speed magnetic-abrasive processing. The surface layer microhardness is found to increase by 28 to 34% as compared with its initial value obtained by polishing.
Laskovnev A. P., Volochko A. T., Makarova Zh. E.
Structural particularities of extruded aluminum-graphite composites. pp. 12--16
Summary: The consideration is made of some kinds of discrete fillers for tribotechnological composite materials with aluminum alloy matrixes as well as of structure and property changes of the Al--C--Al2O3 system bearing after their subjecting to plastic working.
Vityaz P. A., Gorokhov V. M., Prokhorov O. A., Shelekhina V. M.
Mass transport and regular packing of ultrafine (nano-) silica powders in centrifugal field. pp. 17--24
Summary: There has been developed the theoretical model describing the features of monosized silica powders colloidal crystallization in a centrifuge. Calculation results and conclusions from the theory have a good agreement with experimental data on the mass transport and regular packing of ultrafine (nano-) silica powders in the centrifugal field.
Summary: The analysis of a principle of toting is reviewed on an example of the most simple case -- two-stage loading. Outgoing from the kinetic theory of a mechanical fatigue, for conditions, when both stresses of multiply of recurring unit?arc more than initial value of endurance strength, the Palmgren--Miner principle of toting of a fatigue is affirmed and is rotincd, that its validity is limited to the indicated conditions. For two-stage loadings of multiply recurring units at different ratio of two parsed stresses the new more general principle of toting is offered in view of a kinetics of damage: decrease of endurance strength during fatigue damage.
Summary: The explanation of one of the factors causing instability of electroerosive treatment of deep narrow apertures is offered. With achievement of depth of an aperture in preparation of the order 4--5 thickness of a copper electrode-tool will be formed conditions for allocation of additional heat in an electrode-tool owing to Thomson effect. By the made estimation, the value of additional heat is commensurable with heat collecting in an electrode-tool. Reduction of unstable influence of the given factor in practice needs acceptance of special procedure.
Steblov A. B., Philippov V. V., Lenartovich D. V., Tishchenko V. A.
The strained condition of the piece during the rolling on the billet mills and blooming. pp. 32--37
Summary: The results of modelling of strained condition of samples surface during the flat rolling are indicated. The influence of the form factors of deformation zone, the parameters of section and the conditions of rolling of ingots with a various gradient of temperature in the section on the strained condition is investigated.
Kozhevnikova G. V.
Investigation of the effect of external moment of forces on stressed state during cross-werge rolling. pp. 38--43
Summary: The method of graphical construction the fields of slip lines was used for determination of stress values in a site of deformation origin during a cross-wedge rolling of an infinite cylinder by flat plates at an additional torque, stationary process and retardation.
Kozhevnikova G. V.
Investigation of contact geometrical parameters during cross-werge rolling by two rolls. pp. 44--47
Summary: A new cross section scheme is suggested for cross-wedge rolling by two rolls. The cross section geometrical parameters have been determined by the method of upper evaluation. The dependence of the parameters on the ratio of a roll diameter to that of a billet to be rolled is considered.
Klubovich V. V., Bulavin V. A., Tovpenets I. A.
The investigation of type and shape of surgical blades cutting edge influence on the wound process morphology after operation. pp. 48--51
Summary: The cutting matirials model is described, test results of new surgical blades on corpse matirials are presented. Within the frame work of the model and medical tests results the cutting mechanisms, the cutting side shape characteristics and cutting edge microgeometry is discussed.
Golubev V. S., Maklakov A. G., Protskevich L. I.
The processing of woodcutting tools with laser radiation. pp. 52--56
Summary: The paper describes the results obtained when subjecting a woodcutting tool to a laser heat treatment for the purpose of increasing its lifetime. The metallurgical and technological specific pulse and continues laser irradiation are investigated. Production tests have shown that when a woodcutting tool made of tool steels is subjected to a laser processing its life can be increased by a factor of 2 to 2.5. If the tool is provided with hard-alloy inserts of BK 15 type its life can be extended by a factor of 1.5 to 1.9.
Tomilo V. A., Afanasiev N. L.
Employment of periodical profiles for forging "MAZ" automobiles front axle beam. pp. 57--60
Summary: Construction and technology of "MAZ" automobiles front axle beam production are analyzed. It is recommended to use a die rolling for preform profiling before the forging. The preforms die rolling method with a double-T central part is elaborated and experimentally accomplished. It will permit to increase die life and to decrease consumption of metal and amount of hammer strikes.
Summary: Thermal oxides on Ge-doped silicon are studied by UV-VUV photoinjection and capacitance-voltage measurements. It is shown that Ge doping decrease electron mean free path in oxide. The Ge incorporation results in increase of oxide breakdown field by 10--15% too. It is founded that doping of Si--SiO2 system with germanium can be useful in dumping of high-field oxide degradation phenomena.
Zatsepin N. N.
Dynamic parameters of magnetic hysteresis. Part III. Harmonic components of magnetic induction at loop vertexes (magnetic induction mode). pp. 64--69
Summary: The problem of determination of arbitrary magnetic induction harmonic component at the loop vertexes is analytically solved taking into account the surface effect of eddy currents. The quantitative equations for the complex magnitudes of the 1-st and 2-nd harmonics of the magnetic field strength are deducted and their dependence on the depth of the sample layer is analyzed.
Summary: The speech independent speaker identification system which uses on the spectral transition characteristics. The spectral transitions has been investigated as well as numerous weighting functions for improving identification performance. Based on the set of experiments new weighting function is provided.
Botenovsky S. L.
Development of mathematical model of resource situational control with twice integrated dynamics. pp. 74--79
Summary: The simulation results of twice integrated by the dynamics of target error of the resource control law shows that it has conditionally-spending principle. That means it requires forced assumption of resources for minimization of target error, which changes intensively. This is resulted in recommendations of its practical usage at the beginning of organization action, in conflict and before-the-catastrophe situations, where the dynamic target errors are threshold big and require quick and effective reduction.
Matskevich A. N.
Coordinate-parametric optimization of nominal robust system. pp. 80--83
Summary: Devoted to optimization of rated model for robustness of the system with the help of a rebuilt parametric link is surveyed.
Liseichikov N.I.
The problem on the repair stock. pp. 84--86
Summary: Frequently in practice it's necessary to repair of technical objects distributed within a area. Bunching of faulty objects by 2--3 units can be effective way of repairing in this case. Thereafter repair crew consistently puts objects into service, moving from one group to another. In such a way of repair the time required for the movement of the repairing crew is reduced. Besides, the repair time of 2--3 objects concentrated in one place is less than the total time of repairing them separately. That's why the situation is reduced to determination of concentration points of faulty objects groups, combination of their bunching and route of the repair crew. Thus the repairing time of all objects should be minimal. In particular cases the situation is reduced to the problem of the direct-sales representative or designations. The particular example of the considered class of the problems is presented.
Summary: The purposes and necessity of hydraulic-circuit systems dynamics simulation are substantiated. The technique of a hydraulic drives dynamic model building is offered. The hydraulic drive is considered as a lumped-parameter system, the compressibility of a liquid is taken into consideration. The dynamics processes in hydraulic drive is described by equations of motion of a liquid, by equations of the consumptions balance in nodes and by equations of motion of parts of the hydroengine. The features of the solution of a non-linear system equations depicting dynamic processes in hydraulic drives are marked. On the basis of an offered technique the engineering process of a hydraulic drive dynamic model is rotined. The outcomes of calculation and their analysis are resulted.
Biryukov P. M.
The optimization of elastic-inertial parameters of a planetary-cogged reduction gear box. pp. 95--98
Summary: The technique of the optimization of the mechanical system variables is given. The calculation for the drive with the planetary-cogged reduction gear box with cycloidal gearing is proposed.
Bosyakov S. M.
Wave effects in viscous liquids with asymmetrical stress tensor. pp. 99--102
Summary: Problem on movement of extremely viscous half momentary liquid is considered. Expression for asymmetrical tensor of stresses with time of relaxation is derived. Equations of dispersion are obtained. Two limit cases are investigated.
Starovoitov E. I., Yarovaya A. V., Leonenko D. V.
Fluctuations of round sandwich plate under the action of resonance surface loads. pp. 103--108
Summary: The axisymmetric compelled fluctuations of round elastic sandwich plate under the action of periodical surface loads, which frequency coincides with one from the own frequencies of considered system, are investigated. For the kinematic description of package with asymmetrical thickness the hypothesis of broken normal is accepted. The filler is light. The analytical solution of the problem is obtained and its numeric analysis is carried out.
Summary: The experimental and approximated values of thermal conductivity in the liquid phase of three nitrogen containing compounds, i. e. hydrazine (N2H4), ammonia + monomethyl amine mixture (NH3 -- CH3NH2 and hydrazine + ammonia mixture (N2H4 -- NH3 are presented.
Borodulya A. V., Palchenok G. I.
The prospects of application and calculation methods of combustion of densified biofuel in a fluidized bed. pp. 116--123
Summary: Natural and, especially, densified biofuels are shown to be promising renewable and environmentally sound sources for sustainable power generation in Belarus. Combustion characteristics of single particles of twelve model biofuels in a fluidized bed have been experimentally studied. Based on the experimental results, calculation methods for fluidized bed combustion of biomass are proposed, including empirical description and mathematical models of devolatilisation and char combustion of a single particle, as well as a modified mathematical model of the overall combustion process of multiple fuel particles.