Formation of a phase structure of the “fibrils in matrix” type in a composite fibre based on high-density polyethylene and polyethylene terephthalate

Conclusions Regions of component ratio and conditions for obtaining a composite fibre of the fibrils in matrix type have been determined for the HDPE-PET system.At an HDPE-PET ratio of 60:40, phase inversion takes place and a structure of the interpenetration networks type is realized.Under identical fibre spinning conditions, the formation of a phase structure of the fibrils in matrix type can be regulated by varying the temperature.Translated from Khimicheskie Volokna, No. 4, pp. 38–40, July–August, 1987.     

Mathematical modelling of light dependent microorganisms cultivation in countercurrent film reactor

The kinetic parameters of the pseudo-continuous cultivation of green microalgae in the film photobioreactor with countercurrent flows of gas and liquid phases and equipped with spirals on the internal surface of quartz tubes have ben studied. A mathematical model of mass transfer during microalgae cultivation in a film photobioreactor has been developed. The model includes a kinetic equation that considers the effect of the conditions of the cultivation of microalgae populations and cells interactions. A method has been developed for solving equations of the model that uses the Galerkin combination and the finite-element methods.     

Magnetic Viscosity of Rail Steel and its Influence on Magnetization of Rails Tested by High-Rate Magnetic Flaw Detection Methods

It is well known that the depth of magnetization of a rail tested by the high-speed magnetic method depends on two factors, namely, eddy currents and the magnetic viscosity of the rail steel. Both factors act simultaneously, and it is very difficult to separate them in order to estimate the degree of influence of each factor on magnetization of the rail. In the present study a method for distinguishing the effect of the magnetic viscosity of the rail steel against of a background of the eddy-current process is proposed. Real data on the parameters of the magnetic viscosity of the rail steel are given and the possibility of taking its effect on rail magnetization into account is discussed.     

Dynamics of a two-mass parametrically excited vibration machine

This paper presents the results of the investigation of the dynamics of a two-mass vibration machine whose operation is based on the excitation of multiple combinational parametric resonance. It is shown that the rational complication of the models at the expense of an increase in the number of degrees of freedom and allowance for nonlinearity makes it possible to reveal new dynamical effects and unveil additional possibilities for developing new power-saving machines and technologies.     

The Problem of Coordination of Levels of Short-Circuit Currents in Power Systems

The problem of coordination of short-circuit (fault) currents is considered. Data on the dynamics of variation of the levels of single-phase and three-phase short-circuit currents (their highest values) in networks rated for different voltage are presented for a long-term period. The main factors (integral parameters of the networks) affecting the values of short-circuit currents are listed. Statistics of variation of rated parameters of electrical equipment in past years and in the recent period is presented and predictions for the future are made. Basic methods and means for limiting short-circuit currents are discussed. A method of automatic and stationary network separation and a method of circuit design are described in detail. The efficiencies of different methods are compared. The effect of integral parameters of the network on the maximum level of short-circuit currents is shown. The aspects of the switching life of breakers and of allowance for probabilistic characteristics of faults and for the risk factor of decision-making are considered. It is shown that coordination of the levels of short-circuit currents is a possible means for raising the reliability of power installations and systems.__________Translated from Elektricheskie Stantsii, No. 4, April 2005, pp. 19 – 32.     

Influence of the nature of a condensate material on the formation of an ensemble of islands during cryochemical synthesis from the vapor phase

Structural investigation of the mechanisms of the nucleation of cadmium-sulfide and cadmiumtelluride islands on a substrate cooled to low temperatures (down to 77 K) has been performed. A distribution function, micrographs, and electron diffraction patterns are presented. A correlation between the island size and the heat of formation of the material is revealed. The results are interpreted within the model of the nucleation of 3D islands in a polymolecular adsorbate layer due to the relaxation of its chemical energy.     

Determining the integral dissolution rate of two-phase alloys in cryolite-alumina melts

Electron microscopy and x-ray diffraction analysis are used in studying Cu-Fe and Ni-Fe-Al alloys upon their anodic polarization in a cryolite-alumina melt, thus, clarifying the regularities of their dissolution and the formation of oxide coatings. Based on the results obtained, a technique of determining the integral corrosion rate of the alloys is proposed. Original Russian Text ? A.Yu. Filatov, E.V. Antipov, M.I. Borzenko, S.Yu. Vasil’ev, V.M. Denisov, V.V. Ivanov, S.M. Kazakov, Z.V. Kuz’minova, V.K. Laurinavichyute, V.V. Lunin, D.A. Simakov, V.I. Shtanov, 2008, published in Fizikokhimiya Poverkhnosti i Zashchita Materialov, 2008, Vol. 44, No. 6, pp. 664–668.     

A radiographic facility for the 70-GeV proton accelerator of the institute for high energy physics

A radiographic facility for the 70-GeV proton a ccelerator of the Institute for High Energy Physics is described. The available infrastructure in the initial straight part of the injection channel is used in the facility. The 100-mm-diameter lenses of the injection line ar e intended for transportation of the proton beam from the U-70 accelerator to the accelerating—storage complex. The facility has been designed only for an energy of 50 GeVwith a viewfield of 60 mm and used for imaging of samples with an optical density of >300 g/cm² in the presence of some losses in the line. The optical resolution of the facility is 0.25 mm. A set of experiments aimed at multiframe recording of fast processes were conducted on the facility in 2004-2008. Small-sized explosion-proof chambers, as well as the measuring system for monitoring the state of the chamber and environment, were used in the dynamic experiments.     

Determination of lithium diffusion coefficient in LiFePO4 electrode by galvanostatic and potentiostatic intermittent titration techniques

A new model of lithium-ion transport processes in the LiFePO₄ electrode is proposed. This model takes into account the phase transition LiFePO₄ ↔ FePO₄ accompanying reversible lithium intercalation into the electrode during potential or current steps. The diffusion coefficient of Li⁺ ion and its dependence on the LiFePO₄/FePO₄ phase ratio have been determined by means of processing of experimental potential and current transients in accordance with the model's equations. The results of galvanostatic and potentiostatic intermittent titration techniques are in good agreement. The value of diffusion coefficient varies within 10⁻¹⁰-10⁻¹⁶ cm² s⁻¹ depending on the lithium content in solid solution Li_XFePO₄ and Li_1−XFePO₄ (X < 0.02) or the LiFePO₄/FePO₄ phase ratio.