Rheological behavior of oils in a magnetic field

The influence of magnetic treatment parameters on the rheological properties of oils has been investigated. It has been noted that the strongest effect on these properties is produced by the regime of magnetic treatment — steady-state or flowing, the volume rate of oil flow, and the induction value of the magnetoactivator magnetic field. The optimal regimes of magnetic treatment have been determined. It has been shown that treatment of oil with a magnetic field promotes a decrease in the solidification temperature and the amount of asphalt-resin deposits. __________ Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 79, No. 1, pp. 102–109, January–February, 2006.     

Influence of Optical and Thermophysical Characteristics of Biological Tissue on Its Thermal Conditions Under Laser Irradiation

On the basis of the developed analytical method of solving the heat conduction equation in a multicomponent biological tissue, its thermal conditions under laser irradiation have been investigated. Quantitative data on the temperature fields under a wide variation of the optical and thermophysical parameters in the tissue in the 400– 700-nm range of wavelengths are given. The steady-state regime of the field in the tissue at various depths has been investigated. Estimates of the possible use of the time dependence of temperature under tissue cooling to solve the inverse problem — determine the heat-conductivity coefficient, the parameter of heat exchange with the medium, and the depth attenuation coefficient of light — are given. __________ Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 78, No. 3, pp. 15–21, May–June, 2005.     

Measurement of the magnetic properties of liquid magnetic materials at microwave frequencies

Equations are obtained which give a unique functional relation between the required magnetic properties of a liquid magnetic material and the informative parameters on the position and value of the extrema of the experimental dependence of the reflected signal on the thickness of the layer of material. Various methods and algorithms for solving them are considered, taking the degree of attenuation of the wave in the material into account. __________ Translated from Izmeritel’naya Tekhnika, No. 4, pp. 47–49, April, 2007.     

Reflectionless absorption of electromagnetic radiation in a magnetic layer

The conditions for occurrence of total reflectionless absorption of electromagnetic waves in a layer of magnetic material applied to a metal substrate have been found. Their dependence on the layer thickness and the magnetic properties of the coating has been investigated. The frequency band within which this phenomenon can exist has been determined. __________ Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 80, No. 5, pp. 19–22, September–October, 2007.     

Effect of magnetic anisotropy on the mobility of the boundaries in thin magnetic films

This paper discusses the effect of magnetic crystallographic anisotropy on the mobility of the domain walls in thin magnetic films with an easy axis in the plane of the film. It shows that the stable configuration of a domain wall is a single-vortex Bloch domain wall. Besides this, there are two metastable states of the domain wall—a Néel domain wall and a domain wall with two magnetic vortices along the normal to the plane of the film. It is also shown that the mobilities of the single-vortex and Néel domain walls and the domain wall with two vortices decrease as the anisotropy constant increases and tend to the same value. Pis’ma Zh. Tekh. Fiz. 24, 42–46 (January 26, 1998)     

Gasification of Belarusian oil shales in a filtration-combustion wave

The regimes of gasification of Belarusian oil shales have been analyzed based on a generalized volume-averaged filtration-combustion model. The existence of three basic regimes — those of cocurrent and countercurrent filtration waves and of low-temperature volume pyrolysis — has been established. Data on the conditions of their existence have been obtained. The heat content of a producer gas in shale gasification in a stationary cocurrent filtration-combustion wave with air and oxygen-enriched blast has been evaluated. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 82, No. 2, pp. 205–214, March–April, 2009.     

Estimation of magnetic dipole detection parameters

Expressions are derived for describing the potential characteristics of magnetic dipole detection by geophysical system receivers with magnetometer- and gradiometer-type detectors. The characteristics are compared with the capabilities of correlation receivers to detect a completely known signal. Relations for estimating the accuracy of measurement of detection parameters and for optimizing the design of geophysical receivers in the “location—measurement” operating mode are given. Translated from Izmeritel'naya Tekhnika, No. 7, pp. 52–55, July, 1997.     

Simulation of the supersonic turbulent flow around a cylinder with coaxial disks

The turbulent axisymmetric flow around a stepped body — a cylinder with coaxial front and rear disks — has been calculated with the aid of a VP2/3 package based on multiblock computational technologies and the generalized procedure of pressure correction. The computational model has been tested with the example of a supersonic flow around a sphere. The numerical forecasts made with the use of Spalart–Allmares shear stress transfer and eddy viscosity transfer models have been compared with the data of the aeroballistic experiment, wind tunnel tests, and the results of the calculation of the flow around the disk–cylinder arrangement by a simplified zonal model in a wide range of variation of the incident flow Mach number (from 1.5 to 4). We have obtained a good agreement between the calculated transverse flow density distributions in the front stalling zone and those determined from the interferograms for the wave-drag-rational disk–cylinder arrangement. The influence of the rear disk on the drag of the disk–cylinder–disk arrangement has been estimated.     

Regimes of gasification of lean coal layers

Based on a generalized volume-average model, the regimes of filtration combustion in gasification of lean coal layers, which are of interest for evaluation of the parameters and realization of underground gasification of brown Belarusian coals, have been analyzed. The existence of two basic regimes — those of cocurrent and countercurrent gasification waves — has been established. Data on the characteristics of the regimes and the conditions of their existence have been obtained. __________ Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 79, No. 2, pp. 56–61, March–April, 2006.     

Methane-to-hydrogen conversion in the filtration-combustion wave of rich methane-air mixtures

The superadiabatic-effect-based process of noncatalytic conversion of methane to a hydrogenous synthesis gas in a cocurrent filtration-combustion wave has been considered. The influence of the composition and specific flow rate of the working mixture on the basic parameters of conversion — the maximum temperature in the filtration-combustion wave, the wave’s propagation velocity, and the composition of the reaction products — has been investigated. Filtration-combustion regimes optimum from the viewpoint of the most efficient conversion of methane to a hydrogenous synthesis gas have been found from the experimental data obtained. __________ Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 80, No. 2, pp. 90–95, March–April, 2007.     

Modeling of the sorption deformation of glassy polymer sorbents in interaction with gases in a high-pressure region

Based on the phenomenological-thermodynamics method, a model of sorption deformation of a glassy polymer sorbent — polycarbonate — in interaction with carbon dioxide in a high-pressure region has been proposed. The possibility of describing sorption equilibrium for this system has been analyzed. __________ Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 79, No. 5, pp. 175–179, September–October, 2006.     

Testing of numerical methods,convective schemes,algorithms for approximation of flows,and grid structures by the example of a supersonic flow in a step-shaped channel with the use of the CFX and fluent packages

An unsteady supersonic flow of a nonviscous gas with a Mach number M = 3 in a step-shaped channel has been calculated. The accuracy of the forecasts made has been analyzed on the basis of the Roe dissipation model and the advective upwind splitting method with the use of convective schemes of the second and third orders of accuracy and algorithms for approximation of flows. Triangular and polyhedral grids have been tested. The mechanism of formation of an artificial physical instability on grid structures with a local-gradient adaptation has been considered. It is shown that the existence of a singular point — a right corner — in the computational region causes a large phase change in the evolution of the flow. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 82, No. 2, pp. 326–330, March–April, 2009.     

New composite sorbents of water and ammonia for chemical and adsorption heat pumps

New sorbents of water and ammonia — “salt in porous matrix” composites and “salt on fiber” composites — have been reviewed. The possibility of “constructing” the sorption properties of the composites at the nanophase level by varying their composition, the size of the host-matrix pores, and synthesis conditions has been shown. The application of the new materials in adsorption refrigerating devices has been considered. __________ Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 79, No. 6, pp. 160–175, November–December, 2006.     

Formation of magnetic fields inside massive conducting cylinders

The penetration of strong magnetic fields into a cylindrical vacuum space with massive metal walls has been experimentally investigated. A practical solution on acceleration of the penetration of the magnetic field into the working space has been proposed. __________ Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 80, No. 3, pp. 177–180, May–June, 2007.     

A kinetic approach to the rheology of inhomogeneous systems with account for the interaction of disperse-phase particles

By measuring the optical characteristics of a flow the rheology of a viscous non-Newtonian fluid — an aqueous solution of hydrolyzed polyacrylonitrile — has been studied. The loss of stability by the system with chaotic fluctuations of transparency has been established. A kinetic model, as well as kinetic equations that describe the flow of heterogeneous systems, have been suggested. It is expected that this approach will be used in calculations in oil-and gas production and filtration of non-Newtonian systems in porous media. __________ Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 79, No. 6, pp. 90–97, November–December, 2006.     

Production of carbon nanotubes from an air-propane-butane mixture in a high-voltage atmospheric-pressure discharge with an external magnetic field

The synthesis of nanostructures with carbon nanotubes in a plasma reactor with a high-voltage atmospheric-pressure discharge (voltage 1–4 kV and current to 200 mA) on exposure of the discharge to an external magnetic field with an induction of 0.03 T or higher has been investigated. The composition of the soot products has been studied. The discharge was initiated in a quartz channel between the electrodes from catalytic metals in an atmosphere of hydrocarbons mixed with air. The nanotube yield in the soot product amounted to 10–70%. On imposition of the magnetic field, the yield increased by 10–30%, all other things being equal. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 81, No. 4, pp. 621–629, July–August, 2008.     

Simulation of the turbulent mixing of a passive impurity in a jet mixer

Results of numerical simulation of the mixing of a turbulent jet with a cocurrent incompressible-fluid flow (Schmidt number Sc ≈ 1000) in a cylindrical channel of circular cross section (axisymmetric mixer) with the use of the standard k-ε turbulence model and different models for the averaged value of the mixture fraction and its variance have been given. For the problem of mixing of an inert passive impurity, two regimes of flow — the regime with the formation of a recirculation zone and that without its formation — have been considered. The formulated statistical model has been verified with the use of experimental data and results of calculation by large-eddy simulation. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 81, No. 4, pp. 666–681, July–August, 2008.     

Capabilities of the dynamic quartz-resonator method for determining the viscoelastic parameters of thin liquid layers

The capabilities of the dynamic quartz-resonator method for determining the viscoelastic properties of liquids in thin layers (to 1 μm) have been studied. Aqueous solutions of glycerin of different concentrations and motor oils of different manufacturers have been used. The process of polymerization of éD-22 epoxy adhesive in the presence of a hardener — polyethylene polyamine — has been investigated as the model experiment. It has been shown that the broadening of the resonant curve and the shift of the resonant frequency plotted as functions of the thickness of a liquid layer enable one to single out the elastic and viscous components; this makes it possible to judge the change in the structure of boundary layers with processes that may occur at the interphase boundary. __________ Translated From Inzhenerno-Fizicheskii Zhurnal, Vol. 80, No. 1, Pp. 193–200, January–February, 2007.     

Analysis of the process of mixing of a passive impurity in a jet mixer

The experimental results for two regimes of mixing of a passive impurity in an axisymmetric jet mixer — the mixing of a turbulent jet and a cocurrent flow to form a recirculation zone behind the nozzle and an analogous mixing without the formation of a recirculation zone (Re_d = 10,000) — have been presented. The velocity field has been measured in the mixer cross sections at different distances from the nozzle (0.1 < x/D < 9.1) with a one-component Doppler laser anemometer, whereas the scalar field (concentration of the passive impurity) has been diagnosed by the laser-induced fluorescence method. Based on the scalar distributions obtained, the autocorrelation function and the integral scale have been computed, the form of the probability density function has been restored, and the distributions of the asymmetry and excess coefficients have been constructed. Visualization of flow in the mixer has been carried out. __________ Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 80, No. 2, pp. 46–59, March–April, 2007.     

Rheology of gelating systems

Two different types of physical gels — thermoreversible gels based on ultrahigh-molecular-weight polyethylene and thixotropic ones based on cysteine and silver nitrate — have been investigated using viscosimetric methods. Structural methods (IR and Raman spectroscopy and dynamic light scattering) have been used in interpretation of the rheological data obtained. __________ Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 78, No. 5, pp. 118–122, September–October, 2005.