Application of holographic interferometry for determining the solubility of gases in liquids

The effect of a gas dissolved in a liquid on the variation of the refractive index of the compressed mixture was studied. The compression process was monitored with the aid of a holographic interferometer. The sensitivity of this method allows the compressibility of water and the solubility of helium and nitrogen to be studied at pressures below 4 atm. A procedure for obtaining qualitative and quantitative data on the solubility of gases in liquids is proposed.     

Flow and heat transfer in outlet pipes of cryostatting systems

Flow and heat transfer at mixed convection in the vertical channel connecting a cryogenic vessel and a room temperature zone are considered. The two-dimensional problem of conjugated heat transfer in the metal wall of the channel and in its cavity is solved by the finite difference method. The calculated values of the heat flux into the cold zone and of the temperature of the hot pipe end at different channel wall thicknesses, lengths, diameters, helium flowrates, as well as at different constants of the interaction of heat with the environment are given.A. V. Lykov Heat and Mass Transfer Institute, Academy of Sciences of Belarus, Minsk. Translated from Inzhenerno-fizicheskii Zhurnal, Vol. 63, No. 6, pp. 665–672, December, 1992.     

Calculation of the statistical characteristics of a turbulent flow under the action of external forces

A study is made of the statistical characteristics of isotropic velocity and scalar fields in supply of the kinetic energy of turbulence from the energy of the average flow. Two models based on the distributions of the kinetic turbulence energy and the intensity of scalar-field pulsations by wave numbers and length scales are used for calculation of the statistical characteristics of turbulent velocity and scalar fields. The calculation results are compared to the data of the direct numerical modeling performed under the same initial conditions. __________ Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 79, No. 1, pp. 148–154, January–February, 2006.     

An Efficient Scaling Algorithm for the Minimum Weight Bibranching Problem

Let G=(VG,AG) be a digraph and let S ⊔ T be a bipartition of VG. A bibranching is a subset B⊆AG such that for each node s∈S there exists a directed s–T path in B and, vice versa, for each node t∈T there exists a directed S–t path in B.     

Surface space-charge waves in open guiding structures

Basic definitions related to the main electrodynamic characteristics of surface space-charge waves are formulated. These characteristics and their relationships with the geometric dimensions of guiding structures (a dielectric cylinder and a planar metal-dielectric waveguide) are determined.     

Determination of the propagation velocity of a polymerization wave

We consider the propagation of a plane polymerization wave in an infinite mass assuming that the temperature dependence of the reaction rate is a function of the type of exp Θ−1. Existence conditions for a steady regime are determined. It was found that, for a continuous heat-release function, the minimum possible velocity of the wave is given by two different analytic dependences that transform into one another continuously for some critical value of the dimensionless adiabatic temperature. An approximate analytic expression for the temperature profile of the wave is obtained. Russian Research Center “Applied Chemistry,” St. Petersburg 197198. Translated from Fizika Goreniya i Vzryva, Vol. 33, No. 5, pp. 62–75, September–October, 1997.     

Mass Transfer to a Semi-infinite Medium Accompanied by Reversible Chemical Reactions

A mathematical method is developed for deriving asymptotic relationships for the mass-transfer acceleration factor at the boundary of a semi-infinite medium. This method is applied to systems described by arbitrary first- and second-order kinetic equations. The relationships derived are valid at large values of time. A linear and two nonlinear problems are considered as an example. An expression for the acceleration factor in a reversible chemical reaction is derived for the first time. The potential of the method is limited by the assumption that the diffusion coefficients of all reactants are equal.     

Extraction into a flow of a fluid with a velocity gradient

Unsteady extraction from a system of semi-infinite capillaries to the flow of a fluid with a linear velocity gradient is studied. An assumption that the diffusion in the flow is a quasi-steady-state process is taken to obtain a linear equation for the local mass flux from the pore space, which involves fractional derivatives with respect to time and flow coordinate. Limiting solutions for the total diffusion flux at small and large times that cover the entire time interval are found.     

Compressible-liquid motion in porous medium with flowing and stagnant regions

Filtration equations taking into account both flowing and stagnant regions of a porous medium [1] are solved for a semiinfinite region by the fractional-differentiation method [2, 3], For a given arbitrary pressure change at the boundary of the region the filtration rate at this boundary may be determined.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 38, No. 1, pp. 140–144, January, 1980.