Volume 90, №6

INTEGRAL TRANSFORMATIONS FOR THE GENERALIZED EQUATION OF NONSTATIONARY HEAT CONDUCTION IN A PARTIALLY BOUNDED REGION

A mathematical theory of constructing integral transforms and formulas of their inversion for the generalized equation of nonstationary heat conduction in an infi nite region, bounded from the inside by a plane, a cylindrical, or a spherical surface, and the Green′s function method have been developed. Integral relations for analytical solutions of boundary-value problems in the indicated region are proposed. Illustrative examples are considered.  
Author:  É. M. Kartashov
Keywords:  generalized equation of nonstationary heat conduction, partially bounded region, integral transforms, inversion formulas, Green′s function method
Page:  1279

DETERMINATION OF THE COEFFICIENTS OF HEAT TRANSFER AND FRICTION IN SUPERCRITICAL-PRESSURE NUCLEAR REACTORS WITH ACCOUNT OF THE INTENSITY AND SCALE OF FLOW TURBULENCE ON THE BASIS OF THE THEORY OF STOCHASTIC EQUATIONS AND EQUIVALENCE OF MEASURES

New dependences of the coeffi cients of heat transfer and friction have been presented which are used for calculations in the reactor core at a supercritical water pressure by taking account of the parameters of perturbation in the coolant fl ow: of the intensity and scale of fl ow turbulence. These solutions have been obtained based on stochastic systems of equations for the turbulence and the equivalence of measures between deterministic (laminar) and random (turbulent) fl ows.
 
Author:  A. V. Dmitrenko
Keywords:  supercritical pressure, friction, heat transfer, stochastic equations
Page:  1288

IDENTIFICATION OF THE THERMAL CONDUCTIVITY COEFFICIENT FOR QUASI-STATIONARY TWO-DIMENSIONAL HEAT CONDUCTION EQUATIONS

The problem of identifying the time-dependent thermal conductivity coeffi cient in the initial–boundary-value problem for the quasi-stationary two-dimensional heat conduction equation in a bounded cylinder is considered. It is assumed that the temperature fi eld in the cylinder is independent of the angular coordinate. To solve the given problem, which is related to a class of inverse problems, a mathematical approach based on the method of conjugate gradients in a functional form is being developed.  
Author:  Yu. M. Matsevityi, S. V. Alekhina, V. T. Borukhov, G. M. Zayats, and A. O. Kostikov
Keywords:  inverse heat conduction problem, quasi-stationary heat conduction equation, thermal conductivity coeffi cient, method of conjugate gradients, functional identifi cation
Page:  1295

ON INVERSE COEFFICIENT HEAT-CONDUCTION PROBLEMS ON RECONSTRUCTION OF NONLINEAR COMPONENTS OF THE THERMAL-CONDUCTIVITY TENSOR OF ANISOTROPIC BODIES

The authors are the fi rst to present a closed procedure for numerical solution of inverse coeffi cient problems of heat conduction in anisotropic materials used as heat-shielding ones in rocket and space equipment. The reconstructed components of the thermal-conductivity tensor depend on temperature (are nonlinear). The procedure includes the formation of experimental data, the implicit gradient-descent method, the economical absolutely stable method of numerical solution of parabolic problems containing mixed derivatives, the parametric identifi cation, construction, and numerical solution of the problem for elements of sensitivity matrices, the development of a quadratic residual functional and regularizing functionals, and also the development of algorithms and software systems. The implicit gradient-descent method permits expanding the quadratic functional in a Taylor series with retention of the linear terms for the increments of the sought functions. This substantially improves the exactness and stability of solution of the inverse problems. Software systems are developed with account taken of the errors in experimental data and disregarding them. On the basis of a priori assumptions of the qualitative behavior of the functional dependences of the components of the thermal-conductivity tensor on temperature, regularizing functionals are constructed by means of which one can reconstruct the components of the thermal-conductivity tensor with an error no higher than the error of the experimental data. Results of the numerical solution of the inverse coeffi cient problems on reconstruction of nonlinear components of the thermal-conductivity tensor have been obtained and are discussed  
Author:  V. F. Formalev and S. A. Kolesnik
Keywords:  thermal-conductivity tensor, inverse problems, quadratic and regularizing functionals, gradient-descent method, numerical methods, sensitivity matrix, parametric identifi cation
Page:  1302

OPERATING CAPACITY LIMITS OF COOLED AND UNCOOLED OPTICAL ELEMENTS

Analysis has been made of the possibilities of using uncooled and cooled optical elements, for example, laser mirrors with restricted motion of the optical surface. A simple method comparing and choosing the heat exchanger of the mirror and the mirror itself is proposed  
Author:  Yu. I. Shanin, O. I. Shanin, A. V. Chernykh, and I. S. Sharapov
Keywords:  thermodeformation, heat fl ow, cooling system, optical elements, laser mirror
Page:  1310

ON ONE METHOD OF SOLVING NONSTATIONARY BOUNDARY-VALUE PROBLEMS

An exact analytical solution of the problem on the heat conduction in an infi nite plate with the fi rst-kind symmetric boundary conditions has been obtained using the integral method of heat balance with an additional desired function and additional boundary conditions. The solution of the partial differential equation was reduced to the integration of the ordinary differential equation for the additional desired function. It is shown that the fulfi llment of the differential equation at the boundary points of the computational region is equivalent to its fulfi llment within this region. In the approach proposed there is no need to integrate the indicated equation with respect to the space variable because of  the fulfi llment of the integral condition of heat balance, which allows this approach to be applied to the solution of problems that are diffi cult to solve with the use of classical exact analytical methods  
Author:  I. V. Kudinov, V. A. Kudinov, E. V. Kotova, and A. V. Eremin
Keywords:  nonstationary heat conduction, integral method of heat balance, additional desired function, additional boundary conditions
Page:  1317

IGNITABILITY OF DIESEL FUEL WITH AN INCLUSION OF ULTRAFINE CARBON PARTICLES

Nanosize carbon fuel additions were synthesized by the action of an electric discharge on a diesel fuel. Depending on the discharge regime, variously shaped carbon particles, including planar graphitized ones, were formed in the fuel. Ignitability of the produced samples was assessed by the method of initiation of a foamed fuel sample by a lowcurrent electric arc. The modifi ed fuel showed the improvement of the ignition characteristics in the presence of a nanodispersed solid phase.  
Author:  P. N. Krivosheev, V. V. Leshchevich, S. Yu. Shimchenko, S. V. Shushkov, and O. G. Penyazkov
Keywords:  diesel fuel, electric-discharge treatment, carbon nanoclusters, facility for electric-arc ignition
Page:  1328

SIMULATION OF THE SLOW COMBUSTION-TO-DETONATION TRANSITION IN A HYDROGEN–OXYGEN–INHIBITOR (C2Br2F4) MIXTURE

This paper presents a simulation of the slow (laminar) combustion (defl agration)-to-detonation transition in a mixture of hydrogen and oxygen for two cases: case 1 — the mixture contains no inhibitor, its composition varies depending on the stoichiometric relation, and case 2 — the stoichiometric mixture contains an inhibitor C2Br2F4, its concentration is varied. In the investigation, we solved the equations of combustion gas dynamics obtained on the basis of primary notions "combustion surface" and "fl ame velocity." In the fi rst case, the distance and time of transition to detonation increase rapidly with deviation from the stoichiometric composition of the hydrogen–oxygen mixture. The same is also observed in the second case with increasing inhibitor concentration. Transition to detonation is possible until the inhibitor concentration reaches its limiting value at which laminar combustion is impossible.  
Author:  K. O. Sabdenov, K. E. Sakipov, M. Erzada and S. A. Kasymova
Keywords:  defl agration-to-detonation transition, hydrogen–oxygen mixture, infl uence of inhibitors on the initiation of detonation
Page:  1334

INTENSIFICATION OF THE PROCESS OF FLAME COMBUSTION OF A PULVERIZED COAL FUEL

Consideration is given to a method of mechanoactivation intensifi cation of the fl ame combustion of a pulverized coal fuel through the formation of a stressed state for the microstructure of its particles; the method is based on the use of the regularities of their external (diffusion) and internal (relaxation) kinetics. A study has been made of mechanoactivation nonequilibrium processes that occur in fuel particles during the induced relaxation of their stressed state with a resumed mobility of the microstructure of the particles and intensify diffusion-controlled chemical reactions in them under the assumption that the time of these reactions is much shorter than the times of mechanical action on a particle and of stress relaxation in it. The infl uence of the diffusion and relaxation factors on the burnup time of a fuel particle and on the fl ame distance has been analyzed. Ranges of variation in the parameters of fl ame combustion have been singled out in which the fl ame distance is determined by the mechanisms of combustion of the
fuel and of mixing of combustion products.  
Author:  V. I. Popov
Keywords:  transfer processes, combustion, mechanoactivation, relaxation, stressed state
Page:  1344

REPLACEMENT OF METHANE IN THE HYDRATE BED BY LIQUID CARBON DIOXIDE

A mathematical model is presented and numerical solutions have been constructed for the problem on injecting liquid carbon dioxide into a bed consisting of a skeleton, methane hydrate, and pores fi lled with methane. It is assumed that the process has two stages. At the fi rst, short stage, displacement of the free gas from the pores takes place. At the second, longer stage, replacement of methane by carbon dioxide in the hydrate state and its dissolution occur. The fl ow rates of carbon dioxide and methane, as well as their mass in the considered period of time have been considered.  
Author:  V. Sh. Shagapov, Yu. A. Yumagulova and O. A. Shepel′kevich
Keywords:  fi ltration of liquid carbon dioxide, piston displacement of free gas, replacement of methane, liquid carbon dioxide, methane dissolution, methane hydrate, carbon dioxide hydrate, hydrate formation kinetics
Page:  1353

THE LEVENBERG–MARQUARDT METHOD IN THE PROBLEM OF IDENTIFYING THE ABSOLUTE PENETRABILITY COEFFICIENT OF A BED UNDER CONDITIONS OF TWO-PHASE FIL

The problem of identifying the absolute penetrability coeffi cient of a bed under conditions of two-phase fi ltration by the known values of the fl ow rate of a well at different instants of time is considered. The problem was solved with the use of the Levenberg–Marquardt method and of its two-step variation without and with allowance for the corresponding a priori information.  
Author:  V. Elesin and A. Sh. Kadyrova
Keywords:  two-phase filtration, absolute penetrability of the bed, residual function
Page:  1362

NONLINEAR PLANE WAVES LOCALIZED IN A POROUS MEDIUM WITH HOLLOWS FILLED WITH A LIQUID

The propagation of periodic (cnoidal) longitudinal plane waves and solitons in a porous medium with hollows fi lled with a liquid was investigated on the assumption that the energy of a wave is not dissipated in the medium. The infl uence of the parameters of this system, in particular, the sizes of the spherical hollows, on the main parameters (amplitude and width) of a solitary wave propagating in the medium and the infl uence of the nonlinearity of the velocity of this wave on its amplitude and wave number were determined. The results obtained were compared with the corresponding data for solitons demonstrating classical behavior. The dispersion properties of a porous medium with hollows fi lled with a liquid were considered, and the behavior of the corresponding dispersion curves depending on the changing parameters of the medium was analyzed.  
Author:  S. M. Aizikovich, V. I. Erofeev, and A. V. Leont′eva
Keywords:  liquid-saturated porous medium with hollows, Biot medium, longitudinal plane wave, cnoidal wave, soliton
Page:  1369

CHARACTERISTIC FEATURES OF FLUIDIZATION OF BIDISPERSE BEDS IN SUFFOSION CONDITIONS

Experimental investigation of fl uidization of bidisperse beds of quartz sand and straw pellets at a large ratio of their equivalent diameters is carried out. The infl uence of the mass fraction of pellets on the rate of complete fl uidization of a disperse bed has been established. The inapplicability of the available dependences, based on the use of Ergun′s formula, for describing the results obtained is shown.  
Author:  E. A. Pitsukha, Yu. S. Teplitskii, and É. K. Buchilko
Keywords:  bidisperse bed, suffosion, pellets, quartz sand, fl uidization
Page:  1379

MATHEMATICAL SIMULATION OF THE MIGRATION OF RADIONUCLIDES IN A SOIL MEDIUM UNDER NONISOTHERMAL CONDITIONS WITH ACCOUNT FOR CATALYTIC MICROPARTICLES AND NONLINEAR PROCESSES

The problem of mathematical simulation of the vertical migration of radionuclides in a catalytic porous medium under nonisothermal conditions is considered. A numerical solution of the corresponding one-dimensional nonlinear boundary-value problem is obtained by the fi nite difference method. Numerical experiments are carried out and their analysis is made.  
Author:  A. P. Vlasyuk and V. V. Zhukovskii
Keywords:  boundary-value problem, catalytic porous medium, migration of radionuclides, intraparticle mass transfer, nonisothermal conditions, fi nite difference method
Page:  1386

COMPUTATIONAL MODELING OF THE DEGASSING OF COAL SEAMS

A physico-mathematical model of methane desorption and fi ltration in an undisturbed coal seam in the vicinity of a degassing well is proposed. The results are presented on calculations of the change in the specifi c methane release from this well and in the average content of methane in the coal mass in its vicinity in a degassing time of up to 6 years. A good agreement between the results of calculations of the model and the engineering formulas has been obtained.  
Author:  I. M. Vasenin and A. Yu. Krainov
Keywords:  degassing, fi ltration, methane release, mathematical modeling
Page:  1399

ON THE RHEOLOGICAL CHARACTERISTICS OF ORDINARY WATER IN MICROCRACK CHANNELS

It has been established that the reason for the occurrence of nonlinear effect during the motion of water in microcracks is the magnitude of the distance between the upper and lower slabs, which in what follows will be called the crack thickness. It has been revealed for the fi rst time that the reason for the manifestation of abnormal features in cracks is not only the wall layer but also the microcrack effect, i.e., an analog of the Jamin effect in a porous medium.  
Author:  M. A. Mamedova and R. S. Gurbanov
Keywords:  anomalous water, Jamin effect, limiting shear stress, structural viscosity
Page:  1406

ACOUSTOCONVECTIVE DRYING OF CELLULAR GAS CONCRETE

The present paper is devoted to the investigation of the gas dynamics of cellular gas concrete by the acoustoconvective method developed at the ITPM of the Siberian Branch of the Russian Academy of Sciences and its comparison with traditional thermoconvective and natural drying. A series of experiments have been performed on humidifying specimens and the dependence has been obtained of the rate of moisture absorption for two humidifying regimes: capillary impregnation and sorption. In the acoustoconvective drying regime, it has been shown that the frequency and intensity of the operating fl ow strongly infl uence the dynamics of moisture extraction from the specimens being dried. The obtained kinetic data for thermoconvective drying have a bilinear distribution, and their mathematical treatment permitted determining the velocities of the proceeding processes. The process of natural drying is extremely slow, and the drying velocity is strongly infl uenced thereby by the environment parameters. For mathematical description of the obtained experimental data, a relaxation model was used, which has made it possible to determine the relaxation time for each drying regime.  
Author:  A. A. Zhilin and A. V. Fedorov
Keywords:  acoustoconvective drying, drying of cellular gas concrete, comparison of acoustoconvective and thermoconvective drying, relaxation time
Page:  1412

LASER DIAGNOSTICS OF THE SPRAY CONE STRUCTURE IN LIQUID DISPERSION BY SPRAYERS

A procedure and a setup for determining the spatial distribution of the concentration of droplets in a spray cone formed as a result of liquid dispersion by sprayers are described. The proposed procedure is based on measurement of the spectral coeffi cient of spray cone transmission during laser scanning over the chords of the different sections of the spray cone with subsequent solution of the corresponding inverse problem (of Abel′s equation). The characteristics of the structure of the spray cones obtained with the use of ejective and centrifugal sprayers are given.  
Author:  V. A. Arkhipov, S. A. Basalaev, V. F. Trofimov, and N. N. Zolotorev
Keywords:  laser diagnostics, spray cone, spectral transparency, ejective and centrifugal sprayers
Page:  1427

DYNAMICS OF WAVES IN MULTIFRACTIONAL BUBBLE LIQUIDS

A study has been made of pulsed waves in mixtures of a liquid and a dispersed phase consisting of vapor–gas and gas bubbles that differ in radii and thermophysical properties. A system of differential equations has been proposed for description of the motion of such a mixture and a dispersion relation has been derived for it. A comparison has been made of the dynamics of acoustic waves in mixtures of water with vapor–air bubbles, bubbles of carbon dioxide with steam, and helium bubbles, and also in monodisperse mixtures of water with bubbles of one gas. In the investigations, the qualitative composition of the dispersed phase varied due to the buildup in the volume content of the bubbles of one fraction and the relevant decrease in the content of the bubbles of the other fraction, with the total
volume content of the bubbles being constant.  
Author:  D. A. Gubaidullin and R. N. Gafiyatov
Keywords:  acoustic waves, bubble liquid, dispersion relation, heat and mass transfer
Page:  1433

TRANSVERSE INJECTION OF A JET FROM THE SURFACE OF A FLAT PLATE INTO THE SUPERSONIC FLOW OVER IT

A numerical simulation of a supersonic two-dimensional gas fl ow into which a gas jet is injected from the surface of a fl at plate along the normal to it has been performed. The calculations were carried out using the Reynolds-averaged Navier–Stokes equations closed by the SST model of turbulence. The infl uence of the pressure ratio of the jet on the structure of the fl ow formed as a result of its injection into the supersonic crossfl ow, the angle of inclination of the head shock wave, the length of the separation zone, and the depth of penetration of the jet into the main fl ow were determined. The results of calculations performed for different Mach numbers of the main fl ow and different pressure ratios of the injected jet were compared with the corresponding results of a physical experiment. The data obtained can be used for optimization of the mixing of the injected jet with the main supersonic crossfl ow.  
Author:  K. N. Volkov, V. N. Emel′yanov, and M. S. Yakovchuk
Keywords:  plate, jet, injection, separation, pressure ratio, numerical simulation
Page:  1439

METHOD OF DETERMINING THE AERODYNAMIC CHARACTERISTICS OF A FLYING VEHICLE FROM THE SURFACE PRESSURE

The paper presents a description of the procedure used for determining the aerodynamic characteristics (forces and moments acting on a model of a fl ying vehicle) obtained from the results of pressure measurements on the surface of a model of a re-entry vehicle with operating retrofi re brake rockets in the regime of hovering over a landing surface is given. The algorithm for constructing the interpolation polynomial over interpolation nodes in the radial and azimuthal directions using the assumption on the symmetry of pressure distribution over the surface is presented. The aerodynamic forces and moments at different tilts of the vehicle are obtained. It is shown that the aerodynamic force components acting on the vehicle in the regime of landing and caused by the action of the vertical velocity deceleration nozzle jets are negligibly small in comparison with the engine thrust  
Author:  V. F. Volkov, A. A. Dyad′kin, V. I. Zapryagaev, and N. P. Kiselev
Keywords:  aerodynamic forces, aerodynamic coeffi cients, re-entry vehicle, landing surface
Page:  1445

TRANSITION TO A SOURCE WITH MODIFIED PHYSICAL PARAMETERS BY ENERGY SUPPLY OR USING AN EXTERNAL FORCE

A study has been made of the possibility for the physical parameters of a source/sink, i.e., for the enthalpy, temperature, total pressure, maximum velocity, and minimum dimension, at a constant radial Mach number to be changed by energy or force action on the gas in a bounded zone. It has been shown that the parameters can be controlled at a subsonic, supersonic, and transonic (sonic in the limit) radial Mach number. In the updated source/sink, all versions of a vortex-source combination can be implemented: into a vacuum, out of a vacuum, into a submerged space, and out of a submerged space, partially or fully  
Author:  A. N. Kucherov
Keywords:  physical parameters of a vortex-source combination, maximum velocity, minimum dimension, energy and force action, supersonic, subsonic, and transonic gas flow
Page:  1452

FORCED LONGITUDINAL OSCILLATIONS OF A GAS IN AN OPEN PIPE NEAR THE RESONANCE EXCITATION FREQUENCY

Results of theoretical and experimental investigations of forced longitudinal oscillations of a homogeneous gas in an open pipe near the fi rst natural frequency are presented. It has been established that at the resonance frequency the shape of the gas pressure wave changes with time by a law different from the harmonic one. The amplitude–frequency characteristics of the indicated oscillations have been derived. Satisfactory agreement of the theoretical calculation of the gas pressure oscillation range with experimental data has been obtained.  
Author:  R. G. Zaripov, L. A. Tkachenko, and L. R. Shaidullin
Keywords:  forced longitudinal oscillations, open pipe, resonance frequency of excitation
Page:  1463

EXPERIMENTAL INVESTIGATION OF THE PROPAGATION OF THE THREE-DIMENSIONAL TURBULENT JETS OUTFLOWING FROM RECTANGULAR NOZZLES

An experimental investigation of the averaged parameters of the fl ow in the three-dimensional jets outfl owing from rectangular nozzles with extension parameters varying within a wide range has been performed. The coherent turbulence structure of such a jet was determined.  
Author:  M. S. Isataev, G. Toleuov, and K. A. Esenalina
Keywords:  rectangular nozzle, extension parameter, three-dimensional turbulent jet, large-scale vortex
Page:  1469

FLOW-RATE–PRESSURE CHARACTERISTICS OF A DISK BLOOD PUMP

An experimental model of a disk pump for pumping a liquid has been designed and fabricated. This model was tested on a special stand with the use of a 40% aqueous solution of glycerin whose hydrodynamical characteristics most closely correspond to those of blood. The results obtained lend credence to the view that an implantable blood pump can be developed on the basis of the disk pump  
Author:  A. M. Chernyavskii, A. E. Medvedev, Yu. M. Prikhodko, V. M. Fomin, V. P. Fomichev, A. V. Fomichev, K. A. Lomanovich, T. M. Ruzmatov, and A. M. Karas′kov
Keywords:  disk pump, viscous fl uid, boundary layer
Page:  1475

MATHEMATICAL MODEL OF FLUID FLOW BETWEEN ROTATING NONPLANE DISKS

A mathematical model of viscous fl uid fl ow in the gap of a disk pump with nonplane disks has been developed. The characteristics of the pump — fl ow velocity, pressure drop, stress tensor, and the hydraulic coeffi cient of pump effi ciency — have been calculated. A local pressure minimum in the pump has been detected, which leads to local ″choking″ of fl ow and to a decrease in the pressure characteristics and in the pump effi ciency. The parameters causing the local ″choking″ of fl ow have been found, and the means of overcoming this phenomenon are indicated. An optimum inner radius of the disk at which maximum pressure drop and effi ciency of the disk pump are achieved has been established, which made it possible to calculate the optimum parameters of the pump′s disk packet.  
Author:  A. E. Medvedev, Yu. M. Prikhod′ko, V. M. Fomin,a,b,c UDC 621.652.001.24 V. P. Fomichev,a V. P. Chekhov,a A. M. Chernyavskii,d A. V. Fomichev, T. M. Ruzmatov, and A. M. Karas′kov
Keywords:  disk pump, viscous fl uid, boundary layer, mathematical model
Page:  1479

MHD MIXED CONVECTION FLOW IN A ROTATING CHANNEL IN THE PRESENCE OF AN INCLINED MAGNETIC FIELD WITH THE HALL EFFECT

A numerical study of an oscillatory unsteady MHD fl ow and heat and mass transfer in a vertical rotating channel with an inclined uniform magnetic fi eld and the Hall effect is carried out. The conservation equations of momentum, energy, and species are formulated in a rotating frame of reference with inclusion of the buoyancy effects and Lorentz forces. The Lorentz forces are determined by using the generalized Ohm law with the Hall parameter taken into account. The obtained coupled partial differential equations are nondimensionalized and solved numerically by using the explicit fi nite difference method. The effects of various model parameters, like the Hall parameter, Hartmann number, wall suction/injection parameter, rotation parameter, angle of magnetic fi eld inclination, Prandtl number, Schmidt number, etc., on the channel velocities, skin friction coeffi cients, Nusselt number, and the Sherwood number are examined. It is found that the infl uence of the Hartmann number and Hall parameter on the channel velocities and skin friction coeffi cients is dependent on the value of the wall suction/injection parameter  
Author:  A. Mishra and B. K. Sharm
Keywords:  MHD, Hall effect, inclined magnetic fi eld, rotating channel, heat and mass transfer
Page:  1488

DETERMINATION OF THE THERMODYNAMIC AND THERMOPHYSICAL PROPERTIES OF ALTERNATIVE FUELS

The procedure and results of calculation of the thermodynamic and thermophysical properties of alternative fuel are given.  
Author:  K. A. Avdeev, I. E. Agureev, M. Yu. Elagin, and R. N. Khmelev
Keywords:  alternative fuel, wood and vegetable wastes, working substance
Page:  1500

DYNAMIC VISCOSITY AND COMPENSATION EFFECT IN HYDROCARBON MEDIA WITH A HIGH CONTENT OF RESINS AND PARAFFINS

Linear dependences have been obtained for multicomponent hydrocarbon media (oils and high-boiling fractions), which relate the preexponent and the activation energy of viscous fl ow in the Arrhenius equation. A distinctive feature of the established kinetic compensation effect is it existing before and after the phase-transition temperature. The obtained results have been confi rmed by statistical data and make it possible to predict the dynamic viscosity of multicomponent hydrocarbon systems, such as oil and high-boiling fractions.  
Author:  A. A. Boitsova, N. K. Kondrashev and M. Yu. Dolomatov
Keywords:  dynamic viscosity, viscous fl ow, compensation effect, Newtonian multicomponent hydrocarbon medium, high-boiling fractions, activation energy, phase transition
Page:  1506

DIGITAL LASER SPECKLE TECHNOLOGIES IN MEASURING BLOOD FLOW IN BIOTISSUES AND THE STRESSED-STRAINED STATE OF THE MAXILLODENTAL SYSTEM

A method has been developed for estimating the stressed-strained state in the ″orthodontic apparatus–dentin″ system with the use of laser-optical diagnostics based on speckle photography. We have determined the indices of the stressed-strained state in the ″orthodontic apparatus–dentin″ system depending on the composition and form of the orthodontic arch cross section. We have determined the optimum indices of the stressed-strained state of orthodontic arches in patients with periodontium diseases in combination with maxillodental anomalies and deformations, to which the following arches correspond: from copper–nickel–titanium (CuNiTi) alloy with circular (0.012″, 0.013″, 0.014″, 0.016″, 0.018″), and rectangular (0.014 × 0.025″, 0.016 × 0.025″) cross sections, from titanium–molybdenum alloy (TMA) with a rectangular cross section (0.016 × 0.025″), and from stainless steel (SS) with a circular (0.016″, 0.018″) cross section. Direct correlation has been established between indices of the stressed-strained state in the ″orthodontic apparatus–dentin″ system and the periodontium capillary pressure (r = 0.78, p < 0.05), as well as  inverse strong correlation with the periodontium microcirculation intensity (r = –0.88, p < 0.05)  
Author:  S. P. Rubnikovich, Yu. A. Denisova, and N. A. Fomin
Keywords:  speckle technologies, speckle pattern, digital speckle interferometry, biospeckle fi eld, biotissues, stressedstrained state
Page:  1513

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