Volume 91, №5

ON CALCULATING THE MINIMUM FLUIDIZATION VELOCITY OF A QUASI-BIDISPERSE GRANULAR BED

Fluidization of two types of a bidisperse bed with marked bimodality of particle size distribution has been investigated experimentally. The possibility of using the mixture equivalent diameter is shown provided the latter is calculated by the weighted-mean diameter of the particles composing this mixture  
Author:  O. M. Larina, V. M. Zaichenko, R. L. Is′emin, A. V. Mikhalev, N. S. Muratova, S. N. Kuz′min, Yu. S. Teplitskii, V. A. Borodulya, and É. K. Buchilko
Keywords:  bidisperse bed, pellets, quartzsand, olivine sand, anthracite culm, fl uidization, domestic garbage, polydispersity
Page:  1121

ON NUMERICAL SIMULATION OF THE HYDRODYNAMICS AND MIXING OF GAS FLOWS IN A VORTEX CHAMBER

Numerical simulation was carried out in three-dimensional and axisymmetric formulations for the hydrodynamics and mixing of bottom- and tangentially blown air with different temperatures in a cyclone chamber with local supply of tangentially blown air. To calculate vortex fl ows in the chamber, use was made of the most popular turbulence models k–ε, k–ω, and SA. It has been established that the best correspondence between the results of calculation and experimental data on hydrodynamic parameters (velocity and pressure) and air mixing under nonisothermal conditions is furnished by the k–ε and k–ω models of turbulence. Good agreement of the results of numerical simulation of vortex fl ows in the indicated chamber in three-dimensional and axisymmetric formulations has been obtained.  
Author:  E. A. Pitsukha
Keywords:  cyclone chamber, bubbling bed, model of turbulence, mixing, temperature, tangential velocity, longitudinal velocity, bottom blowing, full pressure, axisymmetric flow
Page:  1127

ON THE NATURAL FREQUENCY OF FREE VIBRATIONS OF THE GAS ENVELOPE SURROUNDING A SOLID PARTICLE OR A DROPLET

The behavior of two-phase bubbles containing a solid or a liquid particle in their interior has been studied. A simple formula for the frequency of free radial vibrations of such a bubble has been obtained  
Author:  R. N. Khabeev and N. S. Khabeev
Keywords:  two-phase bubble, natural frequency, radial vibrations
Page:  1138

GENERATION OF ACOUSTIC DISTURBANCES BY A MOVING CHARGED GAS SUSPENSION

Consideration is given to the dynamics of a charged gas suspension in an external electric fi eld. The process of generation of acoustic waves in the carrier medium on instantaneous switch-on of the external electric fi eld setting the dispersed phase in motion is described. The infl uence of the size of particles and of the volume content of the dispersed phase on the intensity of acoustic disturbance is considered  
Author:  A. L. Tukmakov and D. A. Tukmakov
Keywords:  dusty plasma, model of motion of a monodisperse gas suspension, electric fi eld strength, aerodynamicinteraction forces, multiphase medium
Page:  1141

OBLIQUE INCIDENCE OF AN ACOUSTIC WAVE ON A LAYER OF BUBBLY LIQUID

Consideration has been given to the problem of oblique incidence of an acoustic wave on a two-layer medium containing a bubbly-liquid layer. For the mixture ″water–water with air bubbles–water,″ the authors have calculated the coeffi cients of reflection and transmission of the wave as functions of the angle of incidence. Mixture parameters at which the refl ection and transmission coeffi cients take on extremum values have been found and illustrated. A comparison has been made of the transmission coeffi cient and theoretical and experimental results of other authors  
Author:  D. A. Gubaidullin and Yu. V. Fedorov
Keywords:  acoustic wave, angle of incidence, bubbly liquid, refl ection and transmission coefficients
Page:  1148

SIMULATION OF THE HIGH-TEMPERATURE DRYING OF A COMPOSITE MIXTURE IN AN AIR DRIER FOR PRODUCTION OF A BIOCOMBUSTIBLE

A mathematical model is proposed for defi ning the high-temperature drying of a composite mixture comprising a peat and a vegetable biomass in an air drier with the use of equations for the kinetics of drying of the individual components of the mixture and the dynamics of their movement, in which the infl uence of the initial moisture contents of the mixture components and the parameters of the drying agent (its temperature, moisture content, and fl ow velocity) on the kinetics of drying of particles of the composite and the disperse phase is taken into account. It is shown that the kinetics of drying of the indicated mixture is determined by the properties of its fractions, the composition of the mixture as a whole, the stages of its milling, the content of the disperse phase in the drying agent, and the velocity of the drying-agent fl ow. The mathematical model proposed can be used for the intensifi cation and optimization of the working regimes of air driers.  
Author:  D. N. Korinchuk and Yu. F. Snezhkin
Keywords:  composite mixture, peat, biomass, air drier, high-temperature drying
Page:  1155

MODELING OF CONDUCTIVE DRYING POLYGRAPHIC MATERIALS OF CAPILLARY-POROUS COLLOIDAL STRUCTURE

An approach to studying the processes of thermal treatment (heating, drying) of some types of polygraphic materials is proposed, which is based on the theory of nonstationary heat and mass transfer. The approach has been approbated for the process of conductive (contact) drying of a board sheet. The results of numerical investigations are applicable in practice in studying the processes of heat and moisture transfer in capillary-porous colloidal structures, as a result of which optimization of the technological regimes of drying-out and provision of the required qualitative characteristics of the products is possible for both polygraphic and other industrial areas  
Author:  Ya. Yu. Kolyano, T. S. Sass, and E. G. Ivanik
Keywords:  polygraphic industry, capillary-porous colloidal materials, board, conductive drying, convective drying, nonstationary hydrothermal conductivity, gradients of temperature and of moisture transfer potential, initial boundary-value problem, integral Laplace transform, heat- and moisture transfer coeffi cients, thermodynamic parameters
Page:  1165

DEVELOPMENT OF HIGH-VISCOSITY OIL DEPOSITS BY HEAT METHODS

A mathematical model has been developed for the two-dimensional problem on the initial stage of development of a high-viscosity oil pool under the action of heat by the technology of pair horizontal wells, and numerical solutions of this problem have been constructed. The heat expended for warming an oil pool, the evolution of the discharge of a well in it, and the change in the mass of the oil withdrawn from the well in the initial period of its operation, where the pool boundaries insignifi cantly infl uence the temperature and hydrodynamic fi elds around the well, were analyzed. The extrapolation of the numerical solutions obtained to longer times made it possible to estimate the effi ciency of the method proposed for the recovery of a high-viscosity oil and to determine optimum regimes of heat action on it.
 
Author:  V. Sh. Shagapov, Yu. A. Tazetdinova, and A. A. Gizzatullin
Keywords:  high-viscosity oil, heating an oil pool, fi ltration of oil
Page:  1175

SPECIAL FEATURES OF THE DECOMPOSITION OF A HYDRATE IN A MOIST POROUS STRATUM OF FINITE LENGTH UNDER A DEPRESSION ACTION

The problem on the extraction of a gas from a porous stratum of fi nite length saturated with this gas, water, and a gas hydrate under a depression action was solved in the radial-symmetric approximation with regard for the possibility of formation and decomposition of a hydrate in the stratum, the mobility of the liquid, and the Joule–Thomson effect. It was established that, on the opening of the stratum, a hydrate may or may not be formed in the bottomhole zone of the well depending on the initial gas saturation of the stratum and that, in the case where the gas saturation of the stratum is low, in it there take place aperiodic damped oscillations of the gas fl ow rate  
Author:  O. R. Nurislamov and S. A. Lepikhin
Keywords:  porous medium, gas hydrate, decomposition of a hydrate, depression action, Joule–Thomson effect
Page:  1183

MATHEMATICAL SIMULATION OF HUMIDIFICATION OF EARTH ON A SLOPE AND CALCULATION OF ITS SAFETY FACTOR

This paper presents a mathematical model of the simultaneous processes of moisture, heat, and salt transfer in a porous medium, as well as a pattern of calculation of earth stability on a slope depending on the above factors and nonlinear dependences on them of the strength characteristics of the earth. The corresponding boundary-value problem has been solved by the method of radial basis functions. A comparison has been made between the results of numerical experiments showing the relationship between the change in the value of the safety factor and the position of the slip curve depending on the heat, salt, and moisture transfer  
Author:  T. V. Kutya and P. N. Martynyuk
Keywords:  mathematical model, boundary-value problem, heat, moisture, and mass transfer, safety factor, slip surface, adhesion, angle of internal friction, method of radial basis functions
Page:  1189

INFLUENCE OF THE ROTATION OF A BLUNT-NOSE CONE ON THE HEAT EXCHANGE IN THE SUPERSONIC FLOW OVER IT AT AN ANGLE OF ATTACK

Some methods of control over the thermal regimes realized in a supersonic fl ow past a conic body with a nose blunted over a sphere were numerically investigated with account of complicating factors. The solution of the problem on the heat and mass transfer in the boundary layer on the surface of this body in the conjugate formulation made it possible to estimate the infl uence of the nonisothermality of the surface of the body on the characteristics of the indicated transfer. The infl uence of the rotation of such a body made of composite materials on the heat exchange in the fl ow over it was determined  
Author:  K. N. Efi mov, V. A. Ovchinnikov, and A. S. Yakimov
Keywords:  conic body, composite material, rotation, conjugate heat and mass transfer
Page:  1199

HEAT TRANSFER OF CIRCULAR FINNED TUBES WITH NONUNIFORM OPERATIONAL FOULING OF THE INTERFIN SPACE

This paper presents the results of a theoretical calculation of the heat transfer of fi nned tubes for air-cooled heat exchangers having external operational foulings. To determine the heat resistance of the fouling layer, a problem on the temperature distribution in the ring layer has been formulated and solved. The minimum and the surface-average temperatures of the fouling, the heat resistance of the ring layer, and the heat transfer coeffi cient of the fi nned tube heat exchanger have been calculated. It has been shown that the heat transfer coeffi cient is the most strongly infl uenced by the fouling layer thickness at the base of the fi ns.  
Author:  T. B. Karlovich
Keywords:  heat transfer coeffi cient, heat resistance, heat conductivity, temperature, air-cooled heat exchanger
Page:  1211

MATHEMATICAL SIMULATION OF THE THERMAL TECHNICAL CHARACTERISTICS OF EXTERNAL ENCLOSING STRUCTURES WITH AIR SPACES

A screened enclosing structure devoid of heat insulating materials is suggested. To ensure the needed thermal resistance of the external enclosing structure, screens (cement-containing slabs) and closed air spaces between them are employed. With the use of the software suite ANSYS, modeling of the processes of heat transfer in a screened enclosing structure consisting of the main (supporting) part and of screens with air spaces enclosed between them is made. The characteristic features of the process of heat transfer inside the external enclosing structure have been elucidated  
Author:  R. Sh. Mansurov, N. N. Fedorova, D. I. Efi mov, and E. Yu. Kosova
Keywords:  external enclosing structure, closed air space, screen, heat transfer, thermal resistance, mathematical simulation
Page:  1220

CRYSTALLIZATION OF PARAFFIN FROM THE OIL IN A PIPE AND DEPOSITION OF ASPHALTENE–PARAFFIN SUBSTANCES ON THE PIPE WALLS

Problems associated with the crystallization of paraffi n from the oil in conveying pipes and pipes of heat-exchange apparatus and with the deposition of paraffi n particles on the inner surface of these pipes are considered. Diffusion models of the kinetics of crystallization of paraffi n and its deposition under the indicated conditions are proposed. A comparison of the results of calculations by these models with corresponding experimental data has given positive results  
Author:  G. I. Kelbaliev, S. R. Rasulov, P. Yu. Ilyushin, and G. R. Mustafaeva
Keywords:  asphaltene–paraffi n substances, crystallization, deposition, deposits, diffusion kinetics
Page:  1227

MODELING THE OPERATION OF A COOLING SYSTEM FOR RETURN ETHYLENE IN THE PRODUCTION OF HIGH-PRESSURE POLYETHYLENE

The authors have presented a mathematical description of the process of cooling of ethylene in countercurrent heat exchangers of the ″double-pipe″ type, where the ethylene gas is fl owing in the inner tube, and water is moving countercurrently in the intertubular space. Such a system belongs to the basic cycle of polymerization of ethylene by the high-pressure method. Basic properties of heat-exchange apparatuses of a cooling system and its parameters have been described. The interrelation between such physical quantities as pressure, temperature, flow rates of coolants, and heat-transfer surfaces of circulating water and return ethylene has been determined. The proposed model takes account of the ″sticking″ of a liquid polymer onto interior tube walls  
Author:  R. R. Urazov, I. K. Gimaltdinov, T. A. Ishmuratov, and I. G. Khusainov
Keywords:  petroleum chemistry, heat-exchange apparatuses, return ethylene, polyethylene
Page:  1233

CROSS-CORRELATION ANALYSIS OF DIGITAL SPECKLE PHOTOGRAPHY

This paper describes new algorithms for processing noisy specklograms, which permit quantitative diagnostics of the microstructure of shock-wave fl ows with a subpicosecond accuracy with the use of statistical analysis of numerically registered speckle fi elds disturbed by the refraction in the investigated fl ows. The software developed by us permits reconstructing up to 10,000 vector angles of probe radiation defl ection in a two-dimensional region of size 20 × 30 mm² in imaging a speckle fi eld with optical magnifi cation M = 1  
Author:  N. B. Bazylev and N. A. Fomin
Keywords:  speckle photography, cross-correlation analysis, subpicosecond resolution, boundary layer, shock waves
Page:  1241

INFLUENCE OF SPECIAL ADDITIVES IN A WATER AEROSOL ON THE SUPPRESSION OF A FOREST FIRE WITH IT

Experimental investigations on determination of the volume of water with different additives, necessary for the effective suppression of the fl aming combustion and thermal decomposition of typical forest combustible materials (birch leaves, pine needles, aspen twigs, and a mixture of these materials), have been performed. It was established that the addition of a penetrating, a fi re retarding, or a fi re-extinguishing admixture to a water aerosol substantially changes its fi re-extinguishing properties and that the sizes of a hotbed of fi re infl uence the destruction of the forest combustible materials in it. The necessary intensity of spraying of fi re-extinguishing liquids of different compositions over a fi re hotbed was determined.  
Author:  D. V. Antonov, R. S. Volkov, I. S. Voitkov, A. O. Zhdanova, and G. V. Kuznetsov
Keywords:  forest combustible material, hotbed of fi re, thermal decomposition, suppression of combustion, water aerosol, additives
Page:  1250

MODELING OF THE SPARK IGNITION OF A BIDISPERSED AIR SUSPENSION OF COAL DUST

On the basis of the two-phase two-velocity model of a reactive gas-dispersion medium, the authors have formulated a mathematical model of spark ignition of a bidispersed air suspension of coal dust. This model takes account of the mixture′s motion due to the expansion of the gas in its heating. Results of the numerical solution of the problem have been presented. The influence of the size of coal-dust particles on the minimum energy of spark ignition of the air suspension has been analyzed. A comparison of the calculation results and the existing experimental data has shown a satisfactory agreement between them.  
Author:  A. Yu. Krainov and K. M. Moiseeva
Keywords:  bidispersed air suspension, coal dust, spark-ignition energy, numerical modeling
Page:  1260

SPECIAL FEATURES OF THE FORMATION OF DIFFUSION REACTING JETS IN A SWIRLED AIR FLOW

Special features of combustion of diffusion gas fl ames in a cocurrent swirled air fl ow in laminar and turbulent fl ow regimes are considered. The infl uence of the lift force on the shape and position of the fl ame being formed in the course of the outfl ow of fuel jets at different angles to the vertical, has been established. The values of the averaged mass rate of propane burnt out have been determined for the laminar and turbulent regimes of outfl ow under the conditions of different directions of the initial jet impulse and of the free convection-induced lift force  
Author:  O. A. Evdokimov, A. I. Gur′yanov, Sh. A. Piralishvili, S. V. Veretennikov, and M. M. Gur′yanova
Keywords:  combustion, jet, free convection, flame front, fuel, swirled flow
Page:  1267

ESTIMATES OF EQUIVALENT HEAT CONDUCTIVITY COEFFICIENTS OF CARBON NANOTUBES

We have obtained estimates of equivalent heat conductivity coeffi cients of nanostructured elements on the basis of the constructed mathematical model of the thermal energy transfer in a single-layer and a multilayer nanotube surrounded by a homogeneous material in the composite matrix. The values of such coeffi cients permit conditional replacement of nanotubes by solid anisotropic fi bers, which makes it possible, in predicting the effective heat conductivity coeffi cient of a composite modifi ed by carbon nanotubes, to use the known methods developed in detail to fi t fi brous composites  
Author:  V. S. Zarubin, I. Yu. Savel′eva, and E. S. Sergeeva
Keywords:  carbon nanotube, equivalent heat conductivity coeffi cient, composite, mathematical modeling
Page:  1274

ON HYDRODYNAMIC STABILITY OF POISEUILLE AND COUETTE FLOWS OF NANOFLUIDS IN THE CHANNEL BETWEEN CONCENTRIC CYLINDERS

A study is made of the hydrodynamic stability of Poiseuille and Couette fl ows of nanofl uids in the channel formed by concentric cylinders. The infl uence of the concentration and size of silica nanoparticles in ethylene glycol on stability characteristics is considered. The concentrations of the nanoparticles ranges from 0 to 5%, and their size, from 10 to 210 nm. Neutral-stability curves have been constructed; the most unstable modes of perturbations have been found, and their increments have been studied. It has been shown that the action of the nanoparticles is destabilizing in all cases. The higher the concentration of the nanoparticles and the smaller the size of them, the larger the degree of this destabilization. Here, the critical Reynolds numbers decrease substantially and the spectrum of unstable perturbations changes  
Author:  V. Ya. Rudyak and E. G. Bord
Keywords:  nanofl uid, nanoparticles, hydrodynamic stability, laminar-to-turbulent transition, Poiseuille and Couette cylindrical flows
Page:  1282

ATMOSPHERIC LASER DEPOSITION OF SERS-ACTIVE COLLOIDS OF NOBLE METALS (Ag, Au, AND Pt)

A laser procedure is proposed for the precipitation of drop-shaped nanoparticles of noble metals (Ag, Au, and Pt) into aqueous media for using them as active media in surface-enhanced Raman spectroscopy. The detection limit recorded in practice for rhodamine 6G on prepared substrates is no less than 10–9 M. The enhancement factor of the Raman signal in these substrates is estimated as ~8·10⁸  
Author:  V. K. Goncharov, K. V. Kozadaev, K. A. Mel′nikov, E. P. Mikitchuk, and A. G. Novikov
Keywords:  atmospheric laser deposition, SERS-active media, signal enhancement factor, colloids of noble metals
Page:  1291

SYNTHESIS OF CARBON NANOTUBES ON A SHUNGITE SUBSTRATE AND THEIR USE FOR LITHIUM–SULFUR BATTERIES

A shungite mineral has been used as a support material of catalyst particles to synthesize multiwalled carbon nanotubes (MWCNTs). Raman spectroscopy enabled us to follow the formation of MWCNTs. The morphology of synthesized MWCNTs was investigated by a scanning electron microscope and a transmission electron microscope. As a result of simple heat treatment at 300^o C for 3 h in an inert atmosphere, a novel sulfur/multiwalled carbon nanotubes/polyacrylonitrile (S/MWCNT/PAN) composite was synthesized. These methods of obtaining MWCNTs and S/MWCNT/PAN composite based on heat treatment possess the advantages of simplicity and low cost. The introduction of MWCNTs into the composite gives a highly conductive and mechanically fl exible framework with an enhanced electronic conductivity and the ability to absorb polysulfi des between the Li anode and cathode, which leads to an enhanced cyclability and a higher coulombic effi ciency. The cell with this S/MWCNT/PAN ternary composite cathode demonstrates a stable reversible specifi c discharge capacity of 800 mA·h·g^–1 after 50 cycles at a battery C-rate of 0.2 C.  
Author:  T. S. Temirgaliyeva, M. Nazhipkyzy, A. Nurgain, Z. A. Mansurov, and Zh. B. Bakenov
Keywords:  multiwalled carbon nanotubes, lithium–sulfur batteries, composite, CVD.
Page:  1295

EXACT SOLUTION FOR A MAGNETOGASDYNAMICAL CYLINDRICAL SHOCK WAVE IN A SELF-GRAVITATING ROTATING PERFECT GAS WITH RADIATION HEAT FLUX AND VARIABLE DENSITY

An exact similarity solution for a magnetoradiative cylindrical shock wave in a self-gravitating rotating perfect gas is obtained. The density, azimuthal velocity, and magnetic fi eld strength are assumed to vary in an undisturbed medium. It is shown that the fl ow variables, namely, the radial velocity, pressure, magnetic fi eld strength, azimuthal velocity, mass, and the radiation fl ux, decrease from the highest values at the shock front to zero; however, the density tends to infi nity as the symmetry axis is approached. The effects of variation in the magnetic fi eld strength, gravitational parameter, rotational parameter, and in the adiabatic exponent on the fl ow variables and shock strength are discussed. The solutions obtained for self-gravitating and nongravitating media are compared. The total energy of the shock wave is shown to be not constant.  
Author:  G. Nath, Sumeeta Singh, and Pankaj Srivastava
Keywords:  shock waves, magnetogasdynamics, self-gravitating gas, perfect gas, radiation heat flux
Page:  1302

NOVEL ENGINEERING METHOD OF CALCULATION OF HEAT TRANSFER IN A LAMINAR-TURBULENT BOUNDARY LAYER

The authors have carried out investigations of results of systematic numerical solutions to equations of a twodimensional laminar-turbulent boundary layer on the surface of a hemisphere using the Cebeci–Smith algebraic turbulence model [1] modifi ed in [2, 3]. From these investigations, the authors have proposed a novel engineering method of calculation of convective heat transfer, which is based on the use of approximation formulas to calculate the enhancement of convective heat transfer due to turbulent pulsations of the gas in the boundary layer. A comparison has been made of the calculated data corresponding to the employment of this method and analogous data obtained within the framework of formulas of considerable practical use from [4]  
Author:  V. V. Gorskii, M. G. Koval′skii, and M. A. Pugach
Keywords:  boundary layer, turbulence, convective heat transfer, engineering method, turbulent pulsations
Page:  1313

RHEOLOGICAL BEHAVIOR OF ULTRAHIGH MOLECULAR WEIGHT POLYETHYLENE

This paper presents the results of capillary and rotational viscosimetry of ultrahigh molecular weight polyethylene of brand GUR 2122. It has been established experimentally that in rotational viscosimetry, in the gas there are no uniform rates of shear, which does not permit using traditional methods of processing obtained fl ow curves. In capillary viscosimetry, rod-like fl ow is observed. Shear occurs only in the organic near-wall region, and the velocity profi le is far from parabolic and lies within traditional methods of viscosity determination. It has been established experimentally that besides the deformation rate infl uencing the fl ow stability of viscoelastic materials, ultrahigh molecular weight polyethylene also has limiting breaking deformations. The experimental nonmonotone-fl ow curve is described from the viewpoint of the modifi ed Vinogradov–Pokrovskii model.  
Author:  E. V. Slavnov, O. I. Skul′skii, N. V. Shakirov, A. I. Sudakov, Yu. L. Kuznetsova, and O. V. Kryazhevskikh
Keywords:  ultrahigh molecular weight polyethylene, viscosimetry, rheology, methods of processing fl ow curves
Page:  1322

DECAY OF THE SWIRL OF FLOW OF A GENERALIZED NEWTONIAN FLUID

Results of numerical investigations of the decay of swirl in laminar fl ow of a generalized Newtonian fl uid in a circular pipe have been presented. The authors used water and a 0.67% Na–CMC aqueous solution as the working medium. A comparative analysis has been made of the obtained results and the results of other authors. Equations describing the dependence of the intensity of fl ow swirl on the dimensionless axial coordinate have been proposed  
Author:  A. I. Kadyirov, B. R. Abaidullin, and E. K. Vachagina
Keywords:  Newtonian fluid, flow swirl, viscosity, laminar regime, power law, pipe
Page:  1331

INFLUENCE OF FAST THERMAL TREATMENT ON THE ELECTROPHYSICAL PROPERTIES OF SILICON DIOXIDE

The possibility of using fast thermal treatment for improving the electrophysical parameters of the gate dielectric obtained as a result of pyrogenic oxidation of silicon has been investigated. It is shown that such treatment of the gate dielectric allows one to reduce the voltage of the plane zones in it, the charge at the silicon–silicon dioxide interface, and the surface potential, as well as to raise the breakdown voltage of the dielectric and to reduce the leakage current in it  
Author:  V. A. Pilipenko, V. A. Solodukha, and V. A. Gorushko
Keywords:  fast thermal treatment (FTT), impaired layer, silicon plate, solid-phase recrystallization, refraction index, absorption coefficient
Page:  1337

DETERMINATION OF THERMAL CONDUCTIVITY BY THE METHOD OF THE INITIAL STAGE OF WARMING UP A SAMPLE BY A CONSTANT HEAT FLUX

A method of determining the thermal conductivity of a sample at the initial stage of its warming up is presented. The approach is based on the solution of the problem of heating a plane-parallel infi nite plate by a constant heat fl ux. The description of the theoretical base, solution of the problem, and derivation of the working computational formula are given. The main difference of the developed method from the traditional stationary method of determining thermal conductivity is the use of the initial region of the thermogram of sample warming up. This substantially reduces the time of experiments to several minutes. To realize the method, an automated installation has been devised, and the description of its scheme, algorithm, and of the software composition is given. The automation was made on the base of the computer-aided measuring system "Aksamit 6.25" and a PC. The advantages of the developed method and of the automated installation consist of the substantial reduction of the experiment duration with preservation of the needed uncertainty and error of measurement.  
Author:  K. N. Bol′shev, Yu. P. Zarichnyak, and V. A. Ivanov
Keywords:  thermal conductivity, automatization, experiment, method of measurement, device
Page:  1342

EFFECT OF GENERATION OF AUGER DUPLEXES

The physical mechanism underlying the effect of generation of Auger duplexes as a consequence of the electronic level transformation in the case of local energetic effect in the atoms of complex oxides is suggested. It has been established that the effect of the formation of Auger duplexes is independent of the type of radiation acting on an object and is determined by the energy of the affecting particles and by the time of irradiation leading to accumulation of the reactions induced by electrons (ions).  
Author:  I. A. Kossko, A. E. Denisov, M. P. Danilaev, and D. M. Pashin
Keywords:  Auger duplexes, electronic and Auger-ion spectroscopy
Page:  1347

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