The physical-mathematical mass transfer model for a gaseous mixture in a porous body under conditions of condensation and capture of the components is developed. The model has allowed to find the velocity and density distribution of flows of condensed gases and impurities, and on this basis to propose the method of porous structure-aided control of the processes of gas condensation and gas separation occurring in power, heat and mass transfer and chemical-process equipment.
The theoretical description of the account of an influence of internal convective heat transfer of blood in large vessels considered as non-Newtonian medium is suggested. The 19-component model for general hipertermia of a human is developed that allows prediction and optimization of the main thermal parameters of processes (a level of temperature of human organs and tissues, duration of exposure to heat and permissible heat load).
Turbulent heat transfer studies have resulted in the system of equations for one-point density of probabilities and conditional speed of dissipation of scalar functions in a liquid flow which has been solved numerically. The calculation data are confirmed by the results of experimental and direct numerical modeling of turbulent fields of the speed and scalar.
Heat transfer in propane boiling has been experimentally investigated on horizontal pipes (smooth, nonsmooth, and with porous coats) at the specific heat flux values ranged from 1 to 100 kWt/m2 which has allows to reveal the considerable (2--5-fold) enhancement of heat transfer on the surfaces with porous coats and to propose the ways of increasing the efficiency of heat exchangers with porous structures.
Based on the methods of computational high-temperature resolution thermography, correlations are established between the measured and simulated temperature fields of working bodies of machines operated in heterogeneous environment. A highly informative method of thermal (thermographic) testing of heat insulators and constructional elements of steel ladles is developed. A multidimensional numerical model of thermal processes in a human body is developed and investigated. The model allows modeling of adequate temperature distribution on biotissue surfaces.
The generalized Kolmogorov-Feller equation for the density distribution of scattering photons field is derived on the basis of statistical theory for dynamic systems with random structure (in cooperation with Federal Institute for Materials Research and Testing, Germany). Experimental corroboration of basic theoretical results is obtained using unique equipment of the Ohio State University (USA).
Substantial temperature dependence of conical capillary filing with liquid penetrants has been established. Quantitative characteristics of liquid's penetration inside the one-side closed capillaries at various values of surfactant concentration are obtained. Optimal concentrations of surfactant being of practical importance are determined.
A new microwave imaging method to reconstruct dielectric properties of inhomogeneous media using parameters of reflected electromagnetic wave is proposed. The method is based on the Newton-Kantorovich iterative procedure applied to the Riccati equation and demonstrated good stability in the presence of measurement errors for complicated dielectric profiles of high contrast. As a result, it can be utilized for the development of a subsurface radar for visualization of inner structure of tested object.
The different character of the influence of the speed of rise and of the speed of diminishing of pulse magnetic field on the residual magnetizing field distribution in flat ferromagnet is shown. The conditions of stabilization of its magnetic state at local magnetization by nonhomogeneous pulse magnetic field are determined.
The mathematical models of active achievement of reliability of typical elements and hydraulic drive machine systems in character conditions of operation were developed. The main principles of reliability control such as determined, stochastic or adaptive suitable for different available the initial data were founded. Determined and stochastic principles of reliability control suppose the availability of data about levels of control and disturbance action. The adaptive control is employed when these propositions are not known. The observation of specific realizations and process information represents the possible way of resolution of this problem. The probability approach of iteration methods is also employed.
The theoretical approaches to the analysis of circulation of parasitic power losses in closed force contours of truck and automobiles with whole drive axles are developed. It is established that the lowering of energy circulated in closed contour may be achieved by breaking of force flow with help of special "hyper damper" which changes the phase of oscillation of wheel rotation center. Such method of minimization of circulated power may be employed when the weight loads on axles are equal and wheels has the same diameter.
A new methodical approach to direct instrument identification of natural frequencies of mechanical dynamic systems with help of special designed for this aim diagnostics complex "Vibrotest 97" was developed. The essence of the method consists of combined analysis on PC including in the complex some vibration and kinematics spectra received on different regimes of mechanism testing and operating. The natural frequencies are identified as zones of coincides on frequency axis the increased amplitudes of different spectra which have not the displacement during change of testing regimes of investigating mechanism. The validity of proposed method is verified by results of testing of real gear drives.
The dynamic processes which have place in working zones of flat grinding machines during machining have been investigated. The connections between force and vibration characteristics in cutting zone were studied, the control algorithms for reproduction of operation loads during automatized testing were worked out. The design of electronic systems of receiving the control signals during testing and devices of information accumulation and processing about workability of machine tools system were worked out.
The reasons of the most dangerous types of destruction of modern structural steels - fatigue and embrittlement - were investigated. It was established that they are caused by macrolocalization of plastic deformation which is initiated by imperfection of metal structure in near boundary volumes of grains. It was shown for the first time by the direct experiments (investigations of micro-X-ray structure) that obvious connection exists between the grain boundary concentration of impurities elements and forming the structure and dislocation density in near boundary volumes.
The method of layer-by-layer centrifuge forming of coating from powder materials was founded theoretically. It was established that forming of powder layer takes place in possible velocity range: from critical velocity of blank rotation up to critical velocity of holding the whole layer. The dependency of critical velocity from effective friction coefficient and filling of internal space of blank have been received. The design relationship for definition of law of blank rotation velocity change in range of forming velocities on base of modeling of elementary surface layer was calculated. The modification of blank rotation velocity in accordance with the received law gives the layer-by-layer forming powder coating regime.
A number of new aspects of complex influence of thermal and metallurgical parameters of continuous casting formation has been revealed, the main objective laws of obtaining the high-duty cast iron structure with high ductility (20--25%) have been established.
Relations between ferrite amount variations and an iron eutectivity ratio have been obtained. The range of the stable graphitization depending on the silicon content and the carbon/silicon ratio during casting formation at high-rate solidification has been determined.
Theoretical principles of thermal profile formation control for continuous casting roll mould have been created.
The pilot automation plant for investigation of testing and calibration by the technique of a direct comparing the instruments for accounting and control of thermal energy and water has been created and licensed.
The technology of using radiopharmpreparation Tc-99m for diagnostics obtained at the centralized gel-generator has been developed, and clinical tests have been completed. That preparation has been brought into clinical practice. The technology and the plant for Tc-99m obtaining are covered by two patents.
An express-technique for determination of nitrozodimethylamine and nitrites (with the help of analytical spectrophotometric complex "Kanas-1") in liquids and tissues of an organism has been developed. It allows an early diagnostics of oncodiseases to be carried out.
The investigations on generalization of the results on testing of cooling-heating systems with vortical gas-energy dividing tubes in different branches of the national economy at simultaneous their using both as coolers, and as heaters have been carried out. It is shown that in some cases the application of such systems results in sufficient energy saving in comparison with traditional forms of energy transfer.
A mathematical model for calculation of periods of electron (t1), electron-ion (t0) relaxation and equilibrium state electron temperature (Q) for physical processes of metal cold destruction under the influence of high current electron beams (HCEB) has been created. The numerical values of t0»10-9 s, t1»10-13 s and Q obtained by application of this model coincide by order of the magnitude (~15%) with those suggested by other authors. Physical description of ultrasonic vibrations initiation in metallic targets under the influence of HCEB has been considered for the first time. The theoretical possibility of ultrasonic standing waves generation has been revealed, that found its confirmation in scientific publications. It was concluded that generation of ultrasonic standing waves is one of the main reasons of metal cold destruction by HCEB action.
A model of corona pulse discharge in gaseous mixture consisting of air with NOx admixtures has been developed. It was shown that application of corona pulse discharge method for exhaust gases purification from NOx admixtures is competitive to method of radiation purification.
The investigation of the effect of pulse electron radiation and electric field parameters on oxidation kinetics of SO2 has been made for the first time. It was shown that expenditure of energy by application of pulse electron field is 5--6 times lower than that by constant electric field and effectiveness of radiation purification of exhaust gases by application of electric field is 2 times higher than that without it. Calculation basis developed shows good agreement with experimental data and is used for its analysis. A model of SO2 oxidation by high SO2 content under the influence of pulse electron beam has been worked out for the first time that can be used at copper ore enterprises.
Experimental 238U optical cross-sections, angular distributions of scattered neutrons and spectra of emitted neutrons were described in self-consistent approach in the framework of optical model coupled-channels method built on the nuclear wave functions of soft nonaxial-deformed Hamiltonian. The model was successfully applied for prediction of properties of minor actinides lacking experimental data.
Neutron-physical characteristics of thermal column with preliminary moderator and uranium fuel pins and subcritical assemblies with thermal (hydride zirconium and polyethylene moderator) and hard neutron spectra had been investigated. It was shown that thermal neutron flux density in central region of the thermal column may achieve about 2·108 and 1010 n/(cm2s) by neutron generator operation conditions (d,d) and (d,t), respectively. The calculations have been made showed that neutron spectra in lead target surrounded with paraffin by neutron irradiation (En=2.5;14.5 MeV) are similar to the spectra caused by proton (Ep=3.7 GeV) irradiation. To confirm the result experimentally a thermal graphite column with paraffin insertion was designed along with lead target surrounded by paraffin.
The opportunity of fixation of water-soluble 90Sr ingressed into soil up to 25--82% depending on its type with using different chemical additives has been done under laboratory conditions. The results obtained have shown a principle opportunity of transferring mobile forms of radiostrontium into the fixed ones, what allows to prevent 90Sr penetration into plants and to suppress its moving along a biological chain plant -- animals -- a human being.
Recommendations on ensuring safety when operating disposal points of decontamination waste have been developed on the basis of the results of their inspection and certification. The phenomenon of retarding of strontium isotopes emission into water-soluble forms for decontamination waste contained in the disposal points has been found, that allows to specify the forecast of their danger.
The complex of methods, algorithms and programs for estimation of atmospheric transfer of radionuclides and computation of radiation doses with due account of a great number of the factors effecting these processes for various fall-outs at nuclear-dangerous objects has been developed. The usage of the developed techniques ensures the solution of the important applied tasks in the field of monitoring of the environment, such as rehabilitation of a radiation situation as to short-lived isotopes after the Chernobyl NPP accident in the southern regions of Belarus, determination of the parameters of the source of fall-outs by the available experimental measurements, calculation of the dose of external and internal inhalation radiation during the initial period after the accident, investigation of the secondary contamination of the territories under the effect of a linear source of technogenous dusting, as well as radiation consequences of atmospheric effluents at the designed and beyond the design-basis accidents at NPP.
A technique for estimation of the environmental contamination has been developed for modeling biological consequences of a combined effect of chemical contaminants and ionizing radiation. Studying morpho-functional condition of alveolar macrophages at the combined effect of ionizing radiation and sulphur oxides has shown that radiation changes the reaction of macrophages to the effect of sulphur oxides. Reactivity change of alveolar macrophages of animals, irradiated by small doses, to an exogenous contaminant is of a principle significance when analyzing ecological consequences in those cases when radiation itself does not cause violations important from a statistical point of view.
Many-functional and protector coatings were formed on the sublayers from technological materials in vacuum by ion-plasma and gas-plasma flows from inorganic and organic compounds. Composition, structure and elements of composition and structure distributions in the volume of coatings were determined. Functional properties of formed materials were investigated. Couplings between characteristics of the coatings and their composition and structure, and physical parameters of gas-plasma and ion-plasma flows in the vacuum of reactors and physical parameters were formed in the reaction zone on the surface of sublayres also were studied.
A model is created for injection of charged particles in a crystal of gallium arsenide and its interaction with a space charge wave. The model of a progressive wave accelerator is also proposed. It has been used for calculation of major parameters of UHF amplifier with the aid of Monte-Carlo method on the basis of a cluster instability in structures with the Schottky barrier and grating. The developed package of programs allows an optimization of parameters of a progressive wave amplifier on the basis of Ti-Ca-As structure.
The investigation is made of structure, phase composition, electrophysical and gas sensitive properties of unalloyed and silver and palladium alloyed SnO2 films produced from powders of nanometer sizes (60 to 80 nm). The resistance and value of current flowing through test structures are determined depending on the conditions of film structure formation. In an effort to determine gas sensitive properties NO, CO and CH4 have been used as active gases. It has been established that these films do not react with NO up to the maximum concentrations which are provided by control gas mixtures. The films have maximum gas sensitivity to CO and CH4 in the temperature ranges 250 to 300°Ñ and 400 to 450°Ñ, respectively. This permits their use as sensors in CO and CH4 control systems.
The basic parameters of a vacuum arc process have been investigated as regards their effect on optical and decorative properties of titanium and nitride coatings. It has been established that increase of a partial reactive gas pressure in the process of deposition results in shift of a dominant wave length towards a yellow-green spectrum region and an extreme rise of a coating color clarity. The varying of an arc discharge current causes changing of coating color luster and clarity. The extension of a process duration leads to deterioration of luster-forming coating properties. The obtained relationships enable the development of technological film deposition processes which ensure obtaining preset color parameters of items made from different materials.
The schematic diagram has been developed for producing a corundum using a hydrobarothermal method and a potential of a hydrobarothermal reaction has been calculated for increased temperature and pressure by means of the Vladimirov method based on entropy approach. Judging from the calculated data two variants of the reaction are possible. They are a direct interaction of aluminum with an air oxygen, water vapors and water to form a and g aluminum oxides, boehmite and gibbsite as well as interaction of aluminum with water vapors and water to form diaspore. The second variant is more likely to occur under the conditions of the above-mentioned reaction which supports the possibility of producing aluminum oxides using a method of a direct oxidation.
The analytical expressions of porosity functions which enter into a plasticity equation are drawn on the basis of a theoretical investigation of the conditions required for achieving a maximum plastic state of a structure model of a material with continuity defects using different loading diagrams. The complete system of equations for a tough-plastic flow of a material with continuity defects is suggested. The system makes it possible to develop algorithms for a mathematical simulation of structure and shape creating processes for items from discrete materials taking into account their behavior at high temperatures at which there occurs an effect of diffusive-tough self-healing of pores.
Scientific foundation has been developed for regulating performances and technological properties of radiation-modified polymer composites on cross-linking thermoplastic base. Regularities of their structure formation have been defined under the action of high-power fluxes. The dominating cross-linking of macromolecules of a high-molecular mass has been first experimentally proved. New mechanisms have been proposed and theoretically grounded of a three-dimensional structure formation in boundary layers of filled cross-linking polymers. Proceedings from established laws of radiation effect at different process stages (preparation of components, processing into article, etc.) technological principles have been elaborated for manufacturing engineering materials of antifrictional and structural purposes on the base of thermoplastics, thermoelastoplastics and resins.
The molecular-mechanical theory of friction has been further developed on which basis the mechanisms of adhesive wearing of frictional polymer composites under outer friction has been substantiated. A concept has been suggested and experimentally grounded on thermoshrinking destruction of metal-polymer tribosystems under powerful heat actions. A mathematical model has been formulated to compute temperature fields in friction pairs with account of structural changes in contacting materials. Based on results obtained the materials science methods have been worked out for optimizing the structure of composites and machine friction joints design.
Diamond-like carbon films were obtained from pulse plasma streams formed by pulse laser ablation (l=1.06 mm) of carbon targets. It was determined by methods of electron microscopy, X-ray photoelectron spectroscopy (XRPS), measuring of specific resistance and microhardness that for the films there is a considerable dependence of structure and phase composition on laser radiation intensity. The increase of middle energy of plasma particle flows and its density gives the increase of surface concentration of diamond microcrystallites.
It is founded that treating of growing film surface with laser radiation (l=0.53 mm) gives a considerable increasing of films adhesion to different substrates, reduction of internal stresses in carbon deposits and their morphological structure extension, and also increasing of synthesized films phase uniformity out of dependence of substrate type. Under power density more than 102 Wt/cm2 was observed a sharp increasing of synthesized carbon films specific resistance indicated on effective formation of diamond-like phase and selective etching of nondiamond phase of carbon. In addition, the deposition process execution under laser stimulation favors the films structure regulating.
The investigation of laser annealing influence on carbon film properties has shown the increasing of microcrystallite regulating orientation level in initial amorphous matrix. The formation of diamond structure of the films under energy density more than 0.1 J/cm2 was confirmed by XRPS results, after their irradiation it was observed a displacement of bond energy of principal level C1s to more high value from 286.5 to 287.8 eV. The high specific resistance of samples (more than 1013 Ohm×cm) also was concord with forming of diamond structure. The increasing of number and size of graphite clusters was simultaneously observed. Under energy density more than 0.5 J/cm2 the complete graphitization of films has occurred.
On the basis of obtained diamond-like carbon films were created photoelements and investigated their photoelectric parameters in visible and ultraviolet spectrum range. The photoelements in form of sandwiches with the metal-semiconductor-semiconductor (MSS) Al/C/In2O3:SnO2 structure were obtained on silicon substrates coated by dioxide of silicon. It was determined from investigation of spectral dependence of MSS structures that these structures have photosensibility in the region of visible light from green to violet and near ultraviolet. The maximal photo-electromotive forces observed in wavelength ranges 300--3,500 nm. The dependence of photo-electromotive force from concentration of oxygen dissoluted in carbon film was discovered.
On the basis of early elaborated methodology of mass-geometric parameters optimization for operation of speed-tractive characteristics of automobiles, the mathematical modeling have been done, algorithms and preliminary optimized programs have been created. The preliminary optimization includes a solution of multi-criterial tasks providing maximal efficiency of automobiles in exploitation.
The principle of fatigue damages of automobile constructions summarizing in alternate conditions of loading has been theoretically grounded.
The non-contact method for construction deformations measuring under mechanical forces have been developed, which uses laser and television techniques to coordinate measurements. Methodology of errors numerical compensation of measuring deformation components in a certain point of unit has been proposed.
There was achieved a search and foundation of conceptual decisions for creation of high-speed testing module machines. The calculation of dynamic characteristics for high-speed machine have been fulfilled, and its draft project have been done.
There were worked out and experimentally put to the test principles of organization for mechatronic systems for operating the multirange transmissions used intellectual electronic sensors and keys.
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The behavior of a probe of atomic force microscope was investigated under indentation and direct sliding conditions. It was shown that depending on a ratio of a probe - scanning surface hardness it can occur plastic deformation both the probe and the studying surface.
The technique and device for adhesional study of fibers to polymers melt was developed and the influence of temperature and time of contacting on intermolecular interaction of surfaces was shown.
The technology of reception the cellular thermoisolated plates with use of 90--95% wastes of polymers and cellulose fibers is developed.
Source: "Main Results of Fundamental Research. 1996--1997". Eds. F.A.Lakhvich and N.N.Kostyukovich. National Academy of Sciences of Belarus, Minsk, 1998.
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