Thermal conductivity of n-alkanes and 1-alkenes. Undistorted by radiant energy transport. I. Results of experimental study

Results are presented from an experimental study of molecular thermal conductivity of liquid n-alkanes and 1-alkenes using the hot wire method. Measurements were performed at pressures up to 50 MPa and at temperatures from 300 to 640 K. The new experimental data appear to be low by 10% or more when compared to accepted values.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 59, No. 4, pp. 662–667, October, 1990.     

Modeling of diffusion of magnesium in gallium arsenide. 1. Thermal diffusion of Mg in AlxGa1−xAs

A model is developed and an equation is derived for magnesium diffusion in gallium arsenide. Numerical modeling of Al_xGa_1–xAs doping has shown that the suggested model makes it possible to adequately describe all distinctive features of the profile of magnesium atom distribution in thermal diffusion.Belarusian State University of Information Science and Radioelectronics, Minsk. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 67, Nos. 5–6, pp. 433–436, November–December, 1994.     

An Equation for Calculating Nitrogen Density from Measurements of Dielectric Constants

A new equation for determining the density of nonpolar substances based on measurements of dielectric constants is presented. Applying the new equation to nitrogen at a density from 1 to 30 mol·L^–1, the mean deviation of the results calculated from the equation is of the order of 10^–4, which is the same as the uncertainty of the experimental data. Owing to its analytical form, the derived equation can be applied to indicate the density of nonpolar substances with a densitometer, without adding error to the experimental uncertainty. This equation is also capable of determining the mean polarizabilities and molecular diameters, which agree well with results from other investigators. We suggest that the equation derived here can be applied to some other nonpolar substances as well.     

Constitutive analysis to predict high-temperature flow stress in modified 9Cr–1Mo (P91) steel

Constitutive analysis for hot working of modified 9Cr–1Mo (P91) ferritic steel was carried out employing experimental stress–strain data from isothermal hot compression tests, in a wide range of temperatures (1123–1373 K), strains (0.1–0.5) and strain rates (10⁻³–10² s⁻¹). The effects of temperature and strain rate on deformation behaviour were represented by Zener–Hollomon parameter in an exponent-type equation. The influence of strain was incorporated in the constitutive equation by considering the effect of strain on different material constants. Activation energy was found to vary with strain in the range 369–391 kJ mol⁻¹. The developed constitutive equation (considering the compensation of strain) could predict flow stress of modified 9Cr–1Mo steel over the specified hot working domain with very good correlation and generalization.     

Analytical estimate of critical heat flux for water boiling in a tube

An approximate equation for the critical heat flux is obtained. The formula is compared with test data on critical heat fluxes at pressures in the range 9.8–196 bar, water mass velocities larger than 4000 kg/m²/sec, and superheat temperatures of more than 50°C.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 33, No. 1, pp. 59–63, July, 1977.     

Solid helium. I. Ground-state energy and compressibility

The ground-state energy and the compressibility of solid helium is calculated by means of a modified Brueckner theory. The Bethe-Goldstone equation is solved to give the reaction matrix or the effective interaction in coordinate space, and the ground-state energy for the two helium isotopes³He and⁴He is calculated. Also, the compressibility is estimated from the dependence of the ground-state energy on density or molar volume. Both bcc and hcp structures are considered. The calculations are done for two different two-body potentials, an Yntema-Schneider potential given by Brueckner and Gammel, and a Frost-Musulin potential given by Bruch and McGee. Theoretical results for the ground-state energy per particle are 0.2 to 2.6 K for solid³He at a molar volume of 24 cm³/mole, and –2.4 to –5.9 K for solid⁴He at a molar volume of 20 cm³/mole. The corresponding experimental results are –1.0 and –5.6 K, respectively. Theoretical results for the compressibility are 0.0031–0.0042 atm^–1 for solid³He at a molar volume of 22 cm³/mole, and 0.0014–0.0022 atm^–1 for solid⁴He at a molar volume of 18 cm³/mole. The corresponding experimental results are 0.0032 and 0.0014 atm^–1, respectively. The agreement with experimental results is reasonably good since higher order cluster terms are not included in this first approximation.     

Thermal properties of superheated rubidium vapor at temperatures up to 2150 K and pressures up to 5 MPa

Based on generalized experimental data, an equation of state is developed for superheated rubidium vapor, from which thermodynamic properties are calculated and tables that cover the parametric regions of 0.1–5.0 MPa pressure and 975–2150 K temperature are constructed.Deceased.Sergo Ordzhonikidze Moscow Aeronautical Institute. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 68, No. 1, pp. 55–65, January–February, 1995.     

Constitutive equations to predict high temperature flow stress in a Ti-modified austenitic stainless steel

The experimental stress–strain data from isothermal hot compression tests, in a wide range of temperatures (1123–1523 K) and strain rates (10⁻³–10² s⁻¹), were employed to develop constitutive equations in a Ti-modified austenitic stainless steel. The effects of temperature and strain rate on deformation behaviors were represented by Zener-Holloman parameter in an exponent type equation. The influence of strain was incorporated in the constitutive analysis by considering the effect of strain on material constants. The constitutive equation (considering the compensation of strain) could precisely predict the flow stress only at 0.1 and 1 s⁻¹ strain rates. A modified constitutive equation (incorporating both the strain and strain rate compensation), on the other hand, could predict the flow stress throughout the entire temperatures and strain rates range except at 1123 K in 10 and 100 s⁻¹. The breakdown of the constitutive equation at these processing conditions is possibly due to adiabatic temperature rise during high strain rate deformation.     

Heat capacity of liquid organic compounds: Experimental determination and method of group approximation of its temperature dependence

The article describes the experimental method and presents results of the investigation of the heat capacity of liquid n-alcohols and esters. It examines the method of group approximation of the temperature dependence on the example of n-alkanes and n-alkenes.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 39, No. 6, pp. 1054–1060, December, 1980.     

Technique for testing aspherical surfaces

Conclusions The above technique was used for measuring and appropriately processing the results obtained for spherical (concave and convex), parabolic, elliptical, and hyperbolic surfaces (in the case of a spherical surface the measured distance d is the radius r).The obtained results were found to be so precise that they can be recommended for application in the technique for precise practical measurements of surface shapes. This method is based on comparison with surfaces of predetermined shape whose meridional cross section can be represented by an equation for a circle, parabola, and hyperbola.After the surface measurements the meridional cross-section curves were identified according to the method under consideration. Discrepancies in the determined parameters were discovered by comparing the parameters of surfaces with a given shape to the identified surfaces. Thus, the discrepancies for the different surfaces are: spherical — 1·10^–3, elliptical and hyperbolic — 2.10^–2, parabolic — 6·10^–3.Translated from Izmeritel'naya Tekhnika, No. 1, pp. 13–15, January, 1981.     

Closed equation for the structure function of an isotropic turbulent velocity field

A closed equation is derived for the structure function of an isotropic turbulent velocity field in an incompressible fluid. The equation for the characteristic function [1] is used as the initial equation.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 40, No. 6, pp. 980–992, June, 1981.     

Modeling of silicon diffusion in gallium arsenide. 2. Diffusion equation

The equation of diffusion of silicon atoms in gallium arsenide is obtained in a from convenient for numerical solution.Minsk Radio Engineering Institute, Belorussian State University, Minsk. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 66, No. 1, pp. 83–86, January, 1994.     

An equation for calculation of the thermal conductivity of gases and liquids

A unified equation is proposed for calculation of the thermal conductivity of gases and liquids. The procedure for formulation of the equation is illustrated in the example of nitrogen.Translated from Inzhenerno-Fizichesii Zhurnal, Vol.20, No. 1, pp. 119–124, January, 1971.     

Theory of equation of state for real gases 1.

An equation of state for real gases is derived by using correlation relations between the components of the thermal velocity.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 34, No. 3, pp. 519–528, March, 1978.     

Predictions of the Joule–Thomson inversion curves for polar and non-polar fluids from the SAFT-CP equation of state

In this work, we calculate the Joule–Thomson inversion curves of some non-polar fluids, including argon, nitrogen, oxygen, carbon dioxide, n-alkanes (C₁–C₄), ethene, acetylene, benzene and toluene and some polar fluids, including hydrogen sulfide, ammonia, acetone and ethyl ether from the SAFT-CP equation of state. Comparisons with correlated experimental data and reference equation of state indicate that this molecular based equation of state gives good prediction for non-polar fluids. For polar fluids, the predictions of the low-temperature branch are satisfied; but, unfortunately, due to lack of isenthalpic data for high-pressure–high-temperature gas condensate, the reliability of model predictions could not be completely verified. In this work, the performance of some cubic equations of state in predicting the Joule–Thomson inversion curves is also compared with SAFT-CP equation of state.     

A semiempirical equation of state for dense helium

Using eight isotherms in the range 83–323°K at pressures less than 700 bar a semiempirical equation of state for dense helium is constructed, permitting extrapolation into the high-pressure region.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 27, No. 5, pp. 878–882, November, 1974.     

Interfaces Between Two or Three Coexisting Fluid Phases in the System Methane–Perfluoromethane: Calculations with the Born–Green–Yvon Equation

Wetting is studied for the binary mixture methane–perfluoromethane (CH₄–CF₄) with the Born–Green–Yvon (BGY) equation in the attractive mean field approximation (AMFA). The general phase behavior is consistent with the AMFA equation of state. Close to a three-phase equilibrium L₁L₂ V, perfect wetting of the interface L₁ V by the second liquid phase L₂ occurs. Liquid–vapor and liquid–liquid interfaces in the vincinity of the three-phase equilibrium are calculated with the BGY equation, and the surface tension is estimated from the density profiles. The results are compared to previous investigations of wetting in fluid systems, especially the theory of Cahn.     

On One Method of Solving Nonstationary Heat-Conduction Problems for Multilayer Structures

As applied to the solution of the heat-conduction problem for a two-layer structure, the Fourier method is used jointly with the orthogonal Bubnov-Galerkin method. An important feature is the introduction of additional boundary conditions, the need for which is explained by the appearance of an additional parameter μ after the separation of the variables in the input differential equation. The additional boundary conditions are derived from the basic differential equation by differentiating it at the boundary points.__________Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 78, No. 2, pp. 24–28, March–April, 2005.     

Thermodynamic Properties for R-404A

An 18-coefficient modified Benedict–Webb–Rubin equation of state has been developed for R-404A, a ternary mixture of 44% by mass of pentafluoroethane (R-125), 52% by mass of 1,1,1-trifluoroethane (R-143a), and 4% by mass of 1,1,1,2-tetrafluoroethane (R-134a). Correlations of bubble point pressures, dew point pressures, saturated liquid densities, and saturated vapor densities are also presented. This equation of state has been developed based on the reported experimental data of PVT properties, saturation properties, and isochoric heat capacities by using least-squares fitting. These correlations are valid in the temperature range from 250 K to the critical temperature. This equation of state is valid at pressures up to 19 MPa, densities to 1300 kg·m^–3, and temperatures from 250 to 400 K. The thermodynamic properties except for the saturation pressures are calculated from this equation of state.     

A sorption-filtration material for recovery of radioactive iodine from gaseous aerosol exhausts

The efficiency of radioactive iodine recovery was studied as influenced by the type of filtration material and sorbent (OU-A carbon), sorbent surface density, and type and concentration of impregnating agent (AgNO₃, TEA, KI, BaI₂, etc.). A regression equation adequately describing the correlation dependence of ¹³¹I break through the sorption-filtration material on the sorbent surface density (OU-A carbon, 50–200 g m^–2) and impregnating agent concentration (AgNO₃ and TEA, 1–25 wt %) was obtained. The dynamic capacity of impregnated OU-A carbon for molecular iodine was determined; it varies from 170 to 350 mg g^–1. Based on these experimental results, a heat-resistant sorption-filtration material (Filosorb-D) for recovery of radioactive iodine was developed; this material consists of one or two layers of filtration material (FPA, PP-PE) containing imbedded impregnated OU-A carbon (100–500 g m^–2) and one layer of FSB-75-11 or MVFE-22 filtration material to remove aerosols. The operation properties of the Filosorb-D sorption-filtration material are as follows: filtration velocity up to 6 cm s^–1, aerodynamic resistance 480 Pa, efficiency of radioactive iodine recovery 99.0–99.9%, operation life 10 000–15 000 h, and desorption of radioactive iodine and sorbent carry-away < 1–2%.Translated from Radiokhimiya, Vol. 46, No. 6, 2004, pp. 559–563.Original Russian Text Copyright © 2004 by Kornienko, Ampelogova, Krupennikova.