Catalytic oxidation of sulphide ions to elementary sulphur in aqueous solutions over transition metal oxides

The catalytic activity of a wide range of transition metal oxides in oxidation of sulphide ions by air in aqueous medium was studied. Some specific features of the reaction mechanism on some of the studied oxides were considered. The transition metal oxides are promising catalysts for practical application. Some of these oxides will allow the preparation of catalysts possessing activity comparable to that of the cobalt phthalocyanine based catalysts, popular in industrial practice.     

Selecting optimum density of lattice of blades of screw pump impeller

A method is proposed for calculating the optimum density of lattice of blades of screw pump impeller that ensures, for a given cavitation margin (inlet pressure), the first critical condition on the partial cavitation characteristic of the pump. The equations obtained can be used also to calculate the permissible cavitation margin of screw centrifugal and screw mixed-flow pumps as well as of stand-alone screw impeller, provided the geometric and operating conditions of the screw are given. __________ Translated from Khimicheskoe i Neftegazovoe Mashinostroenie, No. 6, pp. 29–33, June, 2007.     

Directions in processing of Tengizsk crude

Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 5, pp. 2–3, May, 1992.     

Application of a Three-dimensional Wind Driven Circulation Model to Assess the Locations of New Drinking Water Intakes in Lake Ontario

A 3D transport model is used to perform a comparative analysis of several potential drinking water intakes located along the northwest shore of Lake Ontario between Toronto and Oshawa. The model is specifically used to assess each intake under both long- and short-term transport of a potential pollutant release from the Pickering Nuclear Generating Station and potential and actual pollutant releases from local land sources respectively. A model based on a 500 m grid resolution is calibrated using data collected in the aftermath of the 1992 tritium spill at the Pickering Nuclear Generation Station and subsequently used to simulate long-term transport. A model based on a 100 m grid resolution is verified using drogue studies and used to simulate short-term transport events. Both models are used to assess pollutant levels at each of nine potential intake locations under different wind scenarios and pollutant releases. Field data for the study included water quality and flow measurements from local sewers and rivers, and estimates of pollutant levels from the local waste water treatment plants. This paper describes the model setup for both the long-term and short-term transport models, calibration using field data, long-term transport modeling, short-term transport modeling, and the comprehensive analysis approach used to evaluate the nine potential intake locations proposed. Results indicated that four intakes in particular outperformed other intake locations by maintaining bottom pollutant levels within governmental standards and warning times that exceeded 20 hours.     

Investigation of mechanical and thermophysical properties of composite materials based on “black binders” with the aim of optimizing the process of their cementing

Optimum conditions for cementing prepared roofing paper are determined and an installation for laying prepared roofing paper as a hydroinsulating roofing carpet is designed.Gomel Polytechnic Institute. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 63, No. 2, pp. 151–153, August, 1992.     

The Problem of Estimating the Uncertainty of the Fixed Point Temperature Due to the Presence of Impurities

The main problems in estimating the uncertainty due to the presence of impurities in the material: the absence in the documents of a unique definition of the quantity being measured – the fixed point temperature, the lack of agreed methods of realizing the fixed points and the insufficient justification of the equations used for the estimate, are analyzed. The results of a measurement of the melting point of gallium are presented, which differ in the conditions in which they were realized – with one and two liquid-solid interfaces and different solidification conditions, are presented. The reasons for the considerable difference between the values of the temperatures obtained in these experiments are discussed.     

Deterministic Chaos during First-Order Phase Transitions in a Liquid–Vapor System

A model is developed in which the theory of deterministic chaos for the interface layer is used to treat both homophase and heterophase fluctuations of density (volume) and the fluctuations of pressure, whose duration increases as the critical point is approached. This approach, based on the transition from continuous differential equations to mappings, leads to a number of important consequences in theoretical analysis of high-temperature processes of evaporation and condensation, including the loss of information on the initial conditions, the alternation, and the presence of branching points on bifurcation diagrams.     

Local solutions of the Hamilton-Jacobi-Bellman equation for some stochastic problems

Consideration is given to the control problem of motion of a linear oscillator, which is subject to the external Gaussian and Poisson random actions, with the aim to minimize the mean energy with the aid of the external bounded control force. The hybrid solution method is suggested for the solution of the stated problem. This method relies on the search in a portion of the phase space for the exact analytical solution of the appropriate Hamilton-Jacobi-Bellman (HJB) equation and the numerical solution of this equation in the remaining (bounded) portion of the space. It is proved that the found analytical solutions represent the asymptotics of solutions of the Hamilton-Jacobi-Bellman equation. With the aid of the decomposition method, the obtained results are applied to the problem for the suppression with the aid of the actuator of vibrations of an elastic rod (plate) that is found to be under the action of Gaussian random actions. Results of the numerical modeling are given.