By analytical and numerical studies of the evolution of homogeneous turbulence it has been shown that the molecular Prandtl number =1 is a peculiar (boundary) parameter that separates the cases of formation of the quasi-one-dimensional mixed velocity field (>1), where vertical disturbances due to internal gravitational fields play a leading role, and of the quasi-two-dimensional mixes field in the medium with <1 (the horizontal turbulence with a leading effect of purely turbulent random pulsations).
A new mechanism has been suggested for heat recovery with use of solid sorbents in which the combined action of chemical reactions and physical adsorption is implemented. It makes possible to design original heat-power machines (coolers, heat pumps, thermotransformers) permitting up to 1 kW of cold per 1 kg of sorbent to be obtained.
The regularities are revealed of ecological impact of evaporative cooling towers intended for cooling of circulation water in thermal and atomic power stations. In particular, it is shown that acoustic waves with frequencies less than 10 Hz generated in a cooling tower and propagating in the wind direction for distances up to 2 km (at a wind velocity of 10 m/sec) are most dangerous for the population of adjacent regions. It is also established that at certain combinations of parameters (an air temperature of about 0C, a high relative humidity, a wind velocity towards dwelling houses) a flare of a cooling tower may be a source of intense moistening of building (by a factor of 50 higher than the atmospheric one).
The theory of optical characteristics of the plasma of heavy elements, the two-level model of correction of radiative fluxes in a line spectrum and a package of programs for calculation of the impact of electron and ion beams on a target in three-dimensional geometry and with an account of an external magnetic field have been developed. (In collaboration with the Center of Nuclear Research, Karlsrue, Germany.)
The algorithms of image reconstruction for a new method of medical diagnostics of organs and biological tissues, namely the computational tomography of electrical impedance, have been developed and numerically realized. A diagnostic apparatus is designed for computer-aided diagnostics of mammary gland by diseases by using temperature (thermal) factors. The apparatus substantially complements the methods of mammography, ultrasound and X-ray examination.
The fundamentals of stochastic optimal control of dynamic objects with abrupt changes of properties have been developed and new algorithms of control decreasing the probability of refusals have been received.
By opto-acoustic spectroscopy the transformer function characterizing the process of laser radiation transformation in sound waves, when the light penetrates into magnetic fluids with the organic bases, has been determined for the first time. The dependencies of the laser light absorption in magnetic fluids on the depth penetration and magnetic concentration have been constructed showing that the colloid structure near the phase boundary is substantially inhomogeneous. The principle possibility to control the opto-acoustic transformer function by external magnetic and electrical fields is demonstrated.
On the basis of the model of stochastic impulse processes in ferromagnets under remagnetization the possibility of reconstruction of functions for distribution of the volumes of remagnetization and stress tensor components is shown by solving the appropriate inverse problems. For anisotropic ferromagnets in external magnetic field the regions of values of the material parameters and the field for which the inhomogeneous magnetic state in domain is stable have been determined.
The construction relationships between stress-strain tension curves and uniaxial local dynamic compression were obtained. It has been established the reconstruction methods of material flow stress curves using indentor testing with strain rate 1--2·103I/s.
The phenomenon of the magnetic induction higher harmonic components content increase with the thickness decrease of the sheet ferromagnetic material which is reverse magnetized by low frequency nonuniform magnetic field has been determined. The physical mechanism of the phenomenon and the possibility of its using for non-destructive testing of the material thickness have been studied.
New designs of steam generators and cooler-condensers for manoeuvrable ecologically pure steam-gas plants of small and average capacity, maximum adapted for up-dating of different industries have been developed. The steam generators have the mass smaller by a factor of 3--5 in comparison with foreign analogues. The cooler-condensers with dynamic two-phase layer provide with recovery of heat of more than 70% of low-temperature gas mixtures as well as multistage cleaning of theirs with the efficiency up to 99%.
A new composition ozone-safe refrigerant of high cold efficiency compatible with construction materials of electric motors of domestic production as well as with capacitor oils of Russian production has been developed and tested. (In cooperation with the Joint Stock Company "Atlant", Belarus and the Odessa State Academy of Cold, the Ukraine.)
A complex of experimental investigations carried out at a large-scaled plant with the capacity of 1400 kW has shown that the developed passive safety system practically excludes hard accidents of water-cooled reactors of NPP even at complete absence of energy supply as well as control and service personal. It ensures the possibility of the accident of 10-7 per reactor/year.
The technique for determination of dispersed composition as well as alpha-activity of aerosol, `hot' particles containing nuclides of uranium and transuranium elements has been developed. It is based on the registration of proper alpha-irradiation or fission fragments obtained at their irradiation with thermal neutrons by track detectors. The technique has been experimentally verified on specimens taken from different populated points of Belarus.
The apparatus and program complex was developed and produced, which is devoted to technical diagnostics of machines and mechanisms by the parameters of vibration, noise, statical and dynamical loaded state, temperature and torques. The complex allows to take the measuring information on a real scale by each of 16 channels or by two channels simultaneously and to place it into the memory of personal computer. The feature of the developed software is the accomplishment of control functions of microprocessor processing of the signal from the vibration measuring module, which ensures digit filtration of the reverse component harmonic from a poliharmonic signal.
The method of simulation on a personal computer of the pictures of contact stresses distribution into conjugations of the interacted parts with the surfaces of concerted curvature and the program for calculation of the real values of stresses into cogged engagement were worked out, which are based on the solutions of the elasticity theory in two-dimensional formulation.
As a result of investigating the phenomena of fatigue during the casehardened structural steels destruction it was established, that the structure of laminated martensite has the highest resistance to crack propagation. The maximum limit of the contact endurance (1500--1700 MPa) achieved during the experiment is ensured by the dispersive structure of laminated martensite and of 20--35% of retained austenite. The received results underlay new technologies of surface impregnation of highly stressed parts made of alloyed structural steels.
The module system for control of machines and mechanisms loaded state, as well as for reading and processing the information about the technical systems serviceability parameters during accelerated reliability tests was developed. The multilevel model of loading regime was developed as a component of the integral system for designing and testing the machines mechanical drives, which is suitable for use in research aims when carrying out calculation analysis and experimental evaluation of the machines reliability.
The influence of regimes of intensive shear deformation (ISD) and of ageing on hardening of the age-hardenable Ni-Cr-base alloy XH77TÞP was investigated. It was shown that the ISD results in intensive hardening of the alloy and is accompanied by sharp increase of the dislocation density and by formation of a specific substructure. The optimum ageing regimes are determined, which result in increase of the alloy hardness up to the level of HV 560--580 kgs/mm2.
The theoretical and technological foundations of the grating plates formation of the accumulator lead alloys by the continuous casting method using rotor cristallizer have been developed. The results obtained will allow to create highly efficient technological processes and the production equipment for various accumulator lead alloys plates in rolls.
The analysis of the main physical characteristics of the Accelerator Molten-Salt Breeder (AMSB) for proton, deuteron and a-particle beams with 1 GeV/nuclon energy and the fuel composition 64 mol% LiF -- 18 mol% BeF2 -- 18 mol% ThF4 has been carried out. It was shown that the deuteron beam replacement instead of proton one increases the neutron generation by 24% and a-particle beam -- by 14%, and neutrons have more higher middle energy. The unloaded 233U quantity grows from 480 kg/year for p-beam to 570 kg/year for d-beam and 590 kg/year for a-particles beam. The generated power also grows from 33 MW(t) for p-beam to 440 MW(t) for d-beam and a-particles.
The analysis and theoretical description of some peculiarities of neutron interactions with fissile nucleus have been carried out. In particular, the threshold structure in the (n,2n)-reaction cross sections was described, the approach for consistent prompt fission neutron and gamma-ray spectra multiplicities evaluation was proposed, the model and the program for add-parity level excitation function calculations for heavy deformed nuclei were developed. The models and methods developed will be used for cross section calculations and neutron data evaluation for minor actinide.
The model of shock wave, which is formed in metallic target under influence of high current electron beam and which causes fragile destruction of the target has been developed. It was shown by using of this model that in a case of target heating up to the melting-point the shock wave is formed in the region ~0.3 a0(where a0 -- an electron path in the target).
By theoretical investigations of high current electron beam (HEB) interaction with acoustic wave, which is spreaded in a drift pipe filled with a rarefied inert gas, it was determined that by the passage of HEB through standing (stationary) ultrasonic wave the electromagnetic radiation will appear with parameters depending on parameters both of the acoustic wave and the electron beam.
The possibility of creation of SHF-generator of undulator type was demonstrated.
The computer model of radionuclides migration in surface water in the catchment basin of the Pripyat River which describes self-consistently the processes of advection, dispersion and adsorption/desorption of radionuclides 137Cs and 90Sr was developed. The information structure of hydrological database was created and its filling and verification was made for the rivers of the Pripyat catchment basin. On the basis of system analysis the information structure of computer expert system for estimation of risk associated with toxic and carcinogens contained in food, drinking water and atmospheric air was also developed. A selected estimation of risk for health associated with pesticides and heavy metals contained in food was made.
A number of methods, algorithms and mathematical programs have been developed for evaluation of absolute and comparative efficiency of various methods of interference (agrotechnical and medical measures, decontamination, changing the residence, etc.), the choice of optimal levels of interference when carrying out decontamination of different objects, including the establishment of the order of priority of realization of various measures in the process of restoration of specific regions and distribution of finances and material resources.
The technology of decontamination of dispersed media, such as soil, from the radioactive contamination consisting in division of dispersed medium into volumetric fractions and measurement of specific activity of each fraction has been developed. The fractions of the medium with the specific activity exceeding the permissible one are separated in the field of centrifugal forces according to the product of specific weight by the diameter of particles in the eddy classifier with the aim of further increase of decontamination factor and reduction of the volume of radioactive wastes intended for disposal. The decontamination factor of dispersed media according to the suggested technology is 20 ± 2 with reduction of the radioactive wastes intended for disposal by a factor of 3.
The registration of 69 interim storage sites for products of decontamination generated in 1986--1987 has been carried out. The recommendations on their arranging have been developed which are already used by the state specialized organizations for increasing the radiation safety. The system of control over entering the radionuclides into subsoil waters has been created, including hydrogeological bore holes and the complex of laboratory installations. Studying the processes of migration of radionuclides in the storage sites for products of decontamination has shown the increase in the content of caesium and strontium in the soils under the foundation at the depth of 1.5--2 meters. The content of caesium and strontium radionuclides in the samples of subsoil water doesn't exceed the permissible levels.
The designs of lasers generating a spiral irradiation were developed and a numerical algorithm which helped to determine the conditions ensuring a spiral irradiation with preset parameters was worked out. The phase transition occurring from a homogeneous vortex state to that with one or more vortexes was investigated and the theorem on complex function index of a field intensity was proved. It states that an index over a closed contour is equal to a sum of topological discharges at complex function zeroes of intensity of an electromagnetic field generated by a laser. The laser designs generating a spiral irradiation are also suggested for focusing the charged particles and use in a laser lithography.
The investigation was made of the structure and physical and mechanical properties of tantalum and titanium oxide thin films produced by a magnetron atomization in a residual oxygen atmosphere and with the aid of a thermal oxidation of initial metallic films. It is established that Ta2O5-base MOS films produced by a thermal oxidation can be used for formation of n-channel MOSLSIC with a memory capacity of 1 Mbit and more.
The Fowler--Nordheim parameters were investigated using silicium oxide super-thin films.
The current-voltage tunnel characteristics of MIS structures were obtained in the range from 300 K to 400 K. It is shown that during emission of electrons from a semiconductor to a silicium dioxide super-thin film there exists an oncoming field of an opposite polarity which results in an injection current drop. The shift absence and a slope change of C-V characteristics indicate that there is no charge formation in both dielectric and dielectric-semiconductor interface. This tunnel current behaviour is probably caused by either an accumulation of injected electrons at a date or an activation of a parasitic surface channel.
The development of a multi-media instrument system for processing the experimental data and storing a reference information was completed. The system helped to develop a geographical information system (GIS) using the proceeding of the International Energy Congress (1990), which includes production and consumption of all kinds of energy for more than 100 countries, historical and geographical information and a forecast of the development up to 2000 year. GIS is already used at the Ministry of Fuel and Energetics of the Republic of Belarus.
The temperature in the friction area of bodies with antifriction coatings has been calculated as applied to composite materials science. It has been determined that there exists a range of coating thickness which thermal resistance does not effect the average contact temperature depending on the size of thermal source, sliding duration and combination of thermal properties of coating and substrate materials.
An assumption has been put forward of the temperature dominating influence on submicrorelief transformation at friction. The assumption is confirmed by the data of scanning probe microscopy evidencing that nanometric roughness remains practically unchanged at low temperatures and even under deformations causing plastic changes in the material.
The thermodynamic compatibility of thermoplastic and thermoelastoplasts melts according to a preliminary -irradiation dose has been studied. Using the polyethylene and divinylstyrene thermoplasts as an example, it was shown that the molecular mobility in boundary layers drops due to radiation cross-linking between molecules in oxygen-free medium. This prevents the formation of loose composite porous transfer layers of variable composition. The elaborated effect enables one to increase the wear resistance of polymer mixtures based on composites in 1.5--2 times.
The temperature-time parameters influence of the formation of model systems 'polyethylene terephthalate -- substratum' on the compounds adhesive strength and physical-mechanical polymer properties has been studied. It has been determined that gas inclusions are formed on the interaction boundary of polymer and solid surface at 290--310C. It has been found that a number of dispersed additives introduced into the polymer (among them graphite and soot) decrease the melt tendency to generation of a gas. It has been also shown that most effective method of thermal energy supply in the process of composite prepregs formation is the infra-red heating. It leads to initiation of components interaction only in contact areas without destructional changes in the polymer layer. The optimization of temperature-time regimes and prepregs production conditions enables one to increase the strength properties of prepregs based on structural plastics up to 1.5--1.8 times.
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The method of multiple jets sprays of the polymer melting, getting from single melting generator, has been theoretically founded and experimentally confirmed for the fiber-porous materials. The method allows to increase the process performance up to 30--90% without changing of melting generator power.
The theoretical foundation for the specific friction force calculation providing the appearance and existence of the cork-like sliding (flow) regime of high-filled compositions in the extrusion devices channels has been developed. The top values of specific friction forces for extrusion through round, rectangular, rhombus-like, and circular extrusion channels have been found.
The complex investigation of mechanism and the results of influence of various bacteria types on polyamide fiber have been performed. By atomic-force microscopy it has been shown that aimed biochemical treatment allows on the first stage 'to reveal' fibrous structure of fiber, and then to modify polyamide molecules with active substance groups. Using EPR- and IR-spectroscopy it has been shown that there are two active centers on polyamide through which bacteria can interact with fiber. One of them is nitrogen of amid bound, and the carbon group or carbon atom of polyamide link may be as second. It has been also shown that polyamide modification with different bacteria types led to these centers selecting blocking. The bacteria types and biochemical treatment regimes have been found, which allow to increase the fiber strength by 20%, increase the fiber adhesion to polymer in 1.5--2 times, and decrease the thermoshrinkage of polyamide cord in 1.5--1.8 times.
Using atomic-force microscope the process of forming of thin (<20 nm) silver films on the glass substrates has been investigated. It has been shown that the island films with qualitatively different surface morphology versus of the substrate temperature can be formed. Thus obtained films were used for investigations of Enhanced Raman Scattering on complex chemical compositions. (In cooperation with the Y.Kupala Grodna State University.)
By pulsed laser condensation there were received the semi-crystalline films of metastable phases of carbon, including the diamond phase. There was made the study of influence of pulsed ignition by laser irradiation with wave length of 1.06 m, pulse time of 30 ns and power density of 104--107 Wt/cm2 on laser condensed carbon films structure, deposited on silicon. It was indicated that by changing laser radiation parameters one can syntheses, during laser ignition, the thin films of different phase composition from silicone carbide up to cubic phase of carbon.
There were made the sample models of thin film integral pressure sensors of car electronic systems for pressure in the range of 0--9 atm. The technical description of designed model samples of pressure sensors corresponds to standards for car electronic system sensors and has the parameters analogous to foreign samples. After experimental works the samples can be recommended for industrial production.
There is made a program complex of design process for laser vacuum projection lithography on the basis of the model of vacuum resist film 'development' under pulsed laser irradiation action. The program complex describes the speeding of exhibiting irradiation in vacuum resist film during carrying of intermediate photo original picture on the substrate with film by projection objective with a fixed reduction coefficient. During calculation there were taken in consideration of form, tone, mutual disposition of elements in limits of working field and their size, the wave length of exhibiting irradiation, aperture, laser irradiation degree, the defocusing size. The program has a full-screen interface and graphic mode of displaying the three-dimensional structures received during the calculation. The program complex is programmed in C++ and Modula-2 languages.
A new method of the accidental multifrequency exploitation analysis of the machines constructions' elements has been worked out. Its application to analysis of the constructions elements' loading of automobiles of Minsk and Belarusian Automobile Plants was given. A method of spectrum analysis of accidental signals using the phenomenon of frequency substitution is also worked out.
A new conception of investigation of the perspective mobile machines is worked out, and new technical evaluation criteria of their exploitation characteristics are determined. A new theory of motion and design methods of such machines will be developed in future on the basis of the above mentioned criteria using the system approach.
Source: "Main Results of Fundamental Research.1994". Eds. A.M.Goncharenko and N.N.Kostyukovich. Academy of Sciences of Belarus, Minsk, 1995
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