Propagation of unipolar perturbations in hysteretic media with saturation of nonlinear losses

The propagation and evolution of unipolar perturbation pulses in hysteretic media with saturation of nonlinear losses have been theoretically studied. An exact analytical solution that describes the propagation and evolution of initially triangular pulses in these media has been obtained. Numerical and graphic analyses of the obtained solution are presented.     

Magnetic separators for cleaning of cutting-oil fluids in application and utilization systems

A modernized unit represented as a magnetic disk separator is proposed for the removal of mechanical impurities from cutting-oil fluids.     

Probabilistic characteristics of detection of radio pulses during propagation along the ionospheric lines of satellite communications systems

The radio-pulse distortion methods are discussed under the condition of propagation along ionospheric transmission lines. These methods rely on the stationary spherically symmetric inhomogeneous medium model, which is equivalent to linear filtration. The numerical estimates of radio-pulse distortions based on correlation analysis of distorted radio pulses and the probabilistic characteristics of detection of distorted radio pulses with respect to propagation in free space are determined.     

Assessing channel rolling on a 450 mill

A method of assessing roller grooving for channel rolling is proposed, in which the channel shape is taken into account by means of matrix characteristics. The influence of the channel shape on the rolling force and energy is considered. The relations derived allow the load on the rolling cells to be judged on the basis of the matrix characteristics.     

Simulation of characteristics determining pressure effects on self-diffusion in BCC and FCC metals

Our earlier model has been used to evaluate the characteristics of vacancies, including those determining the effect of pressure on the concentration of vacancies and their diffusion mobility, in some bcc and fcc metals. The characteristics obtained have been compared with the results of simulations performed by other researchers and with experimental data. As distinct from other studies, the vacancy-migration volumes have been found for all the metals studied.     

The choice of an optimal composition and preparation method of non-promoted Pd/Al2O3 and promoted Pd-Co/Al2O3 catalysts for the selective hydrogenation of vinylacetylene

For the purpose of optimizing the chemical composition and technology of synthesis of the catalyst for the acetylene hydrocarbons hydrogenation in industrial streams of butadiene and ethyl-vinylacetylene fractions, the influence of the palladium initial compound nature, the active component concentration, the promotion by cobalt, the molar ratio of palladium to cobalt, the phase composition of the supporter on physical chemical properties, and the activity and selectivity to 1,3-butadiene of the catalysts was studied. The effect of acidic-base characteristics of the supporter on its ability to oligomerize unsaturated hydracarbons has been investigated. It has been established, than the δ-Al₂O₃ supporter is characterized by a low concentration of Bronsted and Lewis acidic sites, decreasing the quantity of oligomers formed on its surface. The optimal composition of the non-promoted KGV-07 catalyst, recommended for the raw butadiene fraction hydrogenation, is 0.5% of Pd deposited from palladium acetate on δ-Al₂O₃ with palladium particles of 16 nm in size, on which the vinylacetylene conversion of 100% and the selectivity to 1,3-butadiene of 69.9% are reached at a temperature of 20°C at the reactor input, hourly space velocity (HSV) of hydrocarbon raws of 700 h⁻¹, molar ratio of hydrogen to ethyl-vinylacetylenes of 4: 1, summary concentration of 49% of acetylene hydrocarbons, and 1.5% of 1,3-butadiene in hydrocarbon raws. The synthesis of the cobalt-promoted KGVP-07 catalyst with 0.5% of Pd deposited from palladium acetylacetonate on δ-Al₂O₃ and molar ratio of Pd: Co = 1: 1 has been developed for the hydrogenation of an ethyl-vinylacetylene fraction with a concentration of acetylene hydrocarbons to 6 wt %, with the vinylacetylene conversion of 100% and the selectivity to 1,3-butadiene of 61.3%, at HSV of the hydrocarbon stream of 700 h⁻¹, temperature of 6°C at the reactor input, and molar ratio of hydrogen to ethyl-vinylacetylene admixtures of 4: 1. Promotion by cobalt leads to the formation of palladium particles at the zero oxidation level and to an increase in their average size from 11 to 14 nm in comparison with the non-promoted Pd-catalyst. In the work, IR-spectroscopy, transmission electron microscopy (TEM), and physicochemical methods have been used to characterize the catalysts texture and supporter phase composition. Pilot tests of the KGV-07 and KGVP-07 catalysts on the Etilen plant unit have proven the correctness of the choice for the catalysts’ optimal chemical composition.     

Pressure distribution in a hydrocarbon-bearing formation based on the daylight surface movement measurements

The article describes the procedure of estimating spatial distribution of pressure in a producing formation under mining by the land surface geodesy survey data. The numerical experiments show that the single-valued resolvability of the inverse problem requires the land surface movement to be measured both in vertical and horizontal directions.     

Serial turbo codes with a low complexity of reception algorithms

The results of investigating the developed efficient procedures of iterative reception of serial turbo codes based on a simple convolutional code with two possible states of a code trellis are presented.