Determination of kinetic parameters of reactions in gas-liquid systems by electrical measurements

Diffusion is one of the processes that determines the physicochemical properties of gas—liquid systems and is accompanied by an increase in the conductivity of the liquid phase of the system. It is proposed that electrodynamic methods be used to determine the parameters of liquid—gas interaction. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 70, No. 1, pp. 68–72, January–February, 1997.     

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.     

Thermophysical Properties of the Refrigerant Mixtures R417A and R417B from Dynamic Light Scattering (DLS)

Dynamic light scattering (DLS) has been used for the measurement of several thermophysical properties of the refrigerant mixtures R417A (50 % by mass 1,1,1,2-tetrafluoroethane—R134a, 46.6 % pentafluoroethane—R125, 3.4 % n-butane—R600) and R417B (79 % by mass R125, 18.25 % R134a, 2.75 % R600). Both refrigerant mixtures are designed for a replacement of R22 (chlorodifluoromethane) in existing refrigeration systems. Thermal diffusivity and sound speed have been obtained by light scattering from the bulk fluid for the liquid phase under saturation conditions over a temperature range from about 283 K up to the liquid–vapor critical point with estimated uncertainties between 1 % and 3 % and between 0.5 % and 2 %, respectively. By applying the method of DLS to a liquid–vapor interface, also called surface light scattering, the saturated liquid kinematic viscosity and surface tension have been determined simultaneously. These properties have been measured from 253.15 K up to the liquid–vapor critical point with estimated uncertainties between 1 % and 3 % for kinematic viscosity and between 1 % and 2 % for surface tension. The measured thermal diffusivity, sound speed, kinematic viscosity, and surface tension are represented by interpolating expressions with differences between the experimental and calculated values that are comparable with but always smaller than the uncertainties. The results are discussed in detail in comparison with literature data and with various prediction methods.     

New system of standard exergies of chemical elements. I. Standard exergies of ionogen elements

A system of standard exergies of chemical elements and individual substances is proposed that is based on the choice of the aqueous phase of the World Ocean — “sea water” — as an environmental niche and the choice of simple (one-element) cations and anions existing in it — with account for their concentrations — as reference substances for their constituting ionogen elements. Standard exergies of ionogen elements are calculated. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 71, No. 3, pp. 516–520, May–June, 1998.     

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.     

Ein Mitbegründer der modernen Medizin- und Wissenschaftsethik: John Gregory (1724–1773) und seineLectures on the Duties and Qualifications of a Physician

The scottish physician and philosopher John Gregory (1724–1773) published in 1770Lectures On The Duties and Qualifications Of A Physician. Besides giving many very concrete and pragmatic rules and proposals concerning medical etiquette and decency, like most medical “codifiers” did before and after him, Gregory also develops a truely “ethical”—in the sense of (moral-) philosophically based—“system of conduct in a physician”. His concept of practicing and teaching ethics in medicine and research combines Bacon's (1561–1626) philosophy of nature and science with both, the general moral philosophy of the religious sceptic David Hume (1711–1776) and the traditional christian-occidental virtues and deontologies upheld by the movement of the so-called “Common-Sense Philosophy”. By thus combinig conservative moral traditions with the modern enlightenment philosophy of empirism, Gregory's teachings establish ethics in medicine and science on a very broad compromise. It can be proved that his very comprehensiveLectures had—particularly via the famousCode of Medical Ethics of Thomas Percival (1740–1804)—a decisive influence on our contemporary concepts of bioethics.      

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.     

Shock waves in multi-component “liquid — gas bubbles — liquid drops” media

Shock waves are experimentally investigated in multi-component “liquid — gas bubbles — liquid drops” media. The data are obtained on the shock wave structure and properties in these multi-component media.     

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.     

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.     

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.     

Modification of the adsorption properties of the dispersed phase of magnetorheological liquids

A rather simple method for modifying the surface of powder carbonyl ion — the most widespread material of the active dispersed phase of magnetorheological liquids — is developed. It is shown that the specimens of liquids prepared based on modified carbonyl iron have an improved sedimentation stability, a viscosity severalfold lower than the initial one, and hence an expanded control range of rheological parameters when the magnetorheological effect is the same as in reference specimens. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 73, No. 3, pp. 476–481, May–June, 2000.     

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.     

The mechanism of nonperiodic motion in porous media as a result of the accumulating effect of nonlinear waves

We carried out a theoretical investigation of the nonlinear mechanism of nonperiodic motion in a saturated porous medium under the prolonged action of elastic waves. Within the framework of a generalization of the Frenkel—Biot—Nikolaevskii model, we suggest a technique for constructing a slow (background) solution that takes into account the accumulating effect of fast nonlinear oscillations. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 70, No. 1, pp. 3–9, January–February 1997.     

Functional approach to the Rayleigh-Bénard problem for a nematic liquid crystal

The derivation of a functional analog of the free energy—the generalized thermodynamic potential— for an open system such as a nematic liquid crystal in a temperature gradient field is proposed. Near the threshold of thermal convection all the hydrodynamic variables can be described by a single complex amplitude w, the order parameter of the system, which enables one to determine the spatial position and the intensity of rotation of the convection rolls that arise. The orthogonality condition for the solutions is shown to yield an Euler equation from which one can recover the generalized thermodynamic potential, the extrema of which correspond to the most probable realizations of the dissipative structures. Pis’ma Zh. Tekh. Fiz. 24, 6–12 (June 26, 1998)     

Turbulent conjugate heat-and mass transfer in chemical conversions in a tubular reactor

A model of turbulent heat-and mass transfer with nonlinear sources (sinks) that appear as a result of chemical reactions of the first and second orders has been developed. The conjugation condition (equality of temperatures and local fluxes) at the reactor — coolant interface was used for this purpose. A finite-difference numerical solution by the alternating direction method is obtained. The influence of the coefficients of turbulent viscosity on heat-and mass transfer is investigated. The model has been tested on the example of modeling fast polymerization processes. It has been established in practical calculations of the processes of fast polymerization that instead of the model with variable coefficients of transfer and velocities of liquid motion one can use its approximation with constant coefficients of transfer and velocities of liquid motion. __________ Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 80, No. 6, pp. 73–85, November–December, 2007.     

Two-component radiation-gasdynamic model of a turbulent fireball

A two-dimensional computational model of the dynamics of a radiating turbulent fireball that can form in accident-induced explosion of a rocket at the launching position or in flight is presented. The model is based on the system of Navier-Stokes equations, two-component diffusion of explosion products (water vapor) in the ambient air, and a multigroup system of equations of thermal radiation transfer. The possibility of employing three models of turbulent mixing — the Prandtl model, the Penner-Haselman-Edwards model, and the Launder-Spalding model — is investigated. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 73, No. 1, pp. 31–38, January–February, 2000.     

Influence of the concentration of a dispersed phase and of the magnetic field on the attenuation of ultrasonic waves in magnetic fluids

The regularities of the propagation of elastic waves of ultrasonic range in magnetic fluids have been experimentally established. The influence of relaxation processes — nonlocal heat exchange and viscous dissipation — on the coefficient of attenuation of sound has been revealed and a comparison to the existing theoretical data has been made. The dependences (anisotropic in form) of the attenuation of the wave’s amplitude on the value and direction of the magnetic field have been determined and an interpretation of the results obtained has been proposed. __________ Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 80, No. 5, pp. 133–140, September–October, 2007.     

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.     

An analysis of the errors in checking the working standards of frequency deviation by indirect measurements

The errors in checking the working standards and frequency derviation—the K2-38 equipment—by indirect measurements are analyzed. Translated from Izmeritel'naya Tekhnika, No. 10, pp. 49–53, October, 1999.