Potential of flow from an annular slit

A study is made of two unsteady axisymmetric problems in the determination of the flow potential of an incompressible fluid outside a surface formed by the rotation of a contour. In the first problem the dimensions of the curve are assumed to be small in comparison with the distance to the axis of symmetry. In this problem methods similar to those used for thin cavities [1] are used to find the asymptotic behavior of the plane flow near the contour. In the second problem the motion of the contour takes place near a cylindrical wall, and it consists of an arc of a circle and a straight segment. This problem is solved by the method of averaging proposed by Yakimov in one of his articles. It is shown that in the neighborhood of the point at infinity this potential behaves asymptotically as a three-dimensional source for a half-space, and in the neighborhood of the slit as a plane flow, the main additional terms being the same as those obtained in the first problem by using Green's theorem.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 6, pp. 167–169, November–December, 1985.Inconclusion, the author thanks Yu. L. Yakimov and R. L. Kreps for the interest and attention they have shown to the study.     

Synthesis of magnesium dicyclopentadienide catalyzed by titanium and vanadium derivatives

Synthesis of magnesium dicyclopentadienide from metal and cyclopentadiene in THF is effectively catalyzed by the derivatives of vanadium and titanium. The kinetics of the synthesis, as well as thermodynamic parameters of reagents adsorption on the magnesium surface, have been determined. The process catalyzed by titanium derivatives is accompanied by the quantitative hydrogenation of cyclopentadiene to cyclopentene whereas the catalysis by vanadium derivatives leads to hydrogen gas evolution. A number of reaction intermediates including Cp₂TiCl, Cp₂TiH₂MgCl, Cp₂Ti(cyclo‐C₅H₇) and Cp₂V, were identified by the electron spin resonance method. The equilibrium constants, enthalpies and entropies of adsorption of metal halides on the magnesium surface were calculated. Copyright © 2001 John Wiley & Sons, Ltd.     

Hydrodynamic solutions of the generalized Boltzmann-Enskog equation

The properties of a kinetic equation are considered for systems of particles with a binary interaction containing a “hard core” and a far-range component. The solutions that correspond to periodic small perturbations of the distribution function are investigated.     

Neutron flux from nondegenerate nonrelativistic neutron gas polarized by a magnetic field

The effect of a strong magnetic field on the average neutron velocity both in an equilibrium neutron system and in a beam of particles flowing from the system is assessed in the context of the statistical thermodynamics of equilibrium systems. The calculations are based on the Maxwell-Boltzmann distribution for a nondegenerate, nonrelativistic, magnetized neutron gas with allowance for Pauli paramagnetism. Byelorussian State University, Brest State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 44–48, April, 2000.     

Oxidation of Zinc and Cadmium with Tricarbonylcyclopentadienylmolybdenum Chloride and Tricarbonylcyclopentadienyltungsten Chloride

The rate of the reaction of zinc and cadmium with tricarbonylcyclopentadienylmolybdenum chloride and tricarbonylcyclopentadienyltungsten chloride and the yield of the final products of these reactions were studied as influenced by the solvent nature. Kinetic features of oxidation of zinc and cadmium with tricarbonylcyclopentadienylmolybdenum chloride in the presence of dimethylformamide were determined. The thermodynamic parameters of adsorption of the oxidizing agent and the ligand on the metal surface were determined.     

Double-diaphragm shock tube at the Ioffe Physicotechnical Institute

Results of numerical calculations of the flow in a double-diaphragm shock tube with a tailored contact surface are reported. The calculations were carried out using a model of an ideal shock tube allowing for the real properties of the driver gas at high pressures and equilibrium thermodynamics of the processes behind the shock waves at Mach numbers M _s1 of the shock wave in the working gas varying in the range 5–25. Flow regimes with a tailored contact surface were obtained for Mach numbers M _s1=6.3, 11, and 15 using the double-diaphragm shock tube at the Ioffe Physicotechnical Institute. Under these conditions, the parameters of the working gas were kept constant for more than 1 ms. The calculated data were compared with the experimental results and it was shown that the calculated data may be used to determine the section lengths in a double-diaphragm shock tube and to estimate its operating time. The calculated values of the initial pressure in the sections of the tube were substantially lower than those achieved experimentally. Measurements were made of the static pressure along the axis of a conical nozzle during the expansion of hydrogen (initial temperature T ₀=293 K) and shock-heated nitrogen (T ₀=4000 K). It is found that the expansion of hydrogen is accompanied by deactivation of the rotational degrees of freedom, and that partial freezing of the vibrational degrees of freedom takes place in the nitrogen stream. Zh. Tekh. Fiz. 67, 88–95 (November 1997)     

Oxidation of Iron and Nickel with 3,5-Di-<Emphasis Type="Italic">tert</Emphasis>-butyl-1,2-benzoquinone in Coordinating Solvents

The final products of oxidation of iron and nickel with 3,5-di-tert-butyl-1,2-benzoquinone in DMSO were identified, and the formal-kinetics relationships of the process were elucidated. The apparent equilibrium constants, enthalpies, and entropies of adsorption of the reactants on the metal surfaces and the rate constants and activation energies of the reactions were determined.