Vol 23, No 3 (2015)

This paper concerns the modelling of physical adsorption and masstransport processes in micropore systems by means of molecular dynamics (MD) simulation. An individual infinite-tube shape periodical-texture 3D pore with the 5-10 LJ potential of the walls was chosen as an example system. The spatial distributions of the sample particles in various timepoints and under various boundary conditions were obtained as a result of the modelling. In addition, the influence of the potential well parameters on the kinetics of the lengthwise adsorption and masstransport processes was shown. Besides, another result of the modelling is kinetic energy distributions without taking into account the effect of the system heterogeneity.

This paper investigates the boundary inverse thermal conductivity problem of determining a value of heat losses in the typical case of the disturbed noisy temperature measurements. Firstly, the smoothing of experimental data by cubic splines smoothing method is applied. Secondly, the method of parametric optimization based on qualitative features of the error of approximation of the calculated temperature field to smoothed experimental data is presented. The time behaviour of approximating curve at different noise level and various value of smoothing parameter is investigated. The solubility of inverse thermal conductivity problem at low noise is shown.

The problem statement peculiarities of the flight program and cargo-traffic scheduling of the International Space Station Russian Segment are considered. The criteria, rules,and constraints which influence the scheduling of the flight program and cargo traffic are described. Using a formalized approach, the paper demonstrates how a dynamic balance of interests of the spacecrafts, the ISS RS modules and on-board systems, as well as flights and cargos, is achieved. It presupposes mutually coordinated consideration of a range of individual peculiarities of the cargos, spacecrafts, the ISS RS modules and on-board systems.The conclusion that the multi-agent technology, domain ontology, and network-centric approach can be efficiently used for the problem solution is proved, since they enable designing flexible self-organizing flight programs and cargo-traffic schedules.

The paper deals with the problem of time-optimal comtrol of batch induction heating process with respect to restriction on maximum value of temperature. Parametric optimization of time-optimal control algorithms is carried out using the alternance optimization method of distributed parameter systems, developed in Samara State Technical University. Optimization procedure is based on the 2D numerical model of coupled electromagnetic and thermal fields, built in finite-element software Cedrat FLUX.

The paper describes a new approach to solving the problem of statistical identification of the impulse response function of a linear dynamic system, which is based on the correlation method using a sign-function analog-stochastic quantization of input and output signals. Sign-function analog-stochastic quantization allows to pass from processing the multi-bit digital samples of input and output signals to processing the integer time samples determined by the change of the result value of thequantization type in question. The main result is the development of numerical algorithms for sequential calculation of the impulse response function discrete samples. This algorithm does not require preliminary direct estimates calculation of the system input signal correlation function and input and output signal cross-correlation function.

The paper presents the results of the investigation into the effect of the mounting-surface form deviations of the shaft and the hollow in the spindle-unit front-bearing housing on its elastic properties. A method and a technique of controlling the spindle-unit stiffness of lathes using a loading device allowing to determine the spindle-unit static radial stiffness when changing the load vector direction are offered. A spindle front-bearing elastic-deformations hodograph obtained by using the method and technique in question confirmed the presence of the bearing spindle-unit stiffness significant anisotropy. The results obtained revealed the dominant factor in the formation of the bearing elastic deformations.The presented method and technique of machine - tool spindle-unit stiffness control, as well as the loading device capable of changing theforce vector direction have shown their efficiency, effectiveness, as well as sufficient ease of implementation which is most favorable for use under operational conditions in the manufacture of measuring-instrument parts.

A set of issues on modelling the thermal processes in power lines during ice melting, and on the calculation of voltage losses in a line is treated. A simplified algorithm taking into consideration the state of aggregation change is offered for the solution of the problem. On the basis of the analysis of the network electric regimes during melting, a conclusion is drawn that the approach offered can be used in 10 and 35 kV networks of a certain length.

Considered the features of design and operation of the induction heating systems of metal treatment under pressure. Focuses on the application of induction heating to rolling and pressing in the industries. Particularity of the design and operation of the inductors at industrial frequency in single-phase and three-phase version was shown. Was made the analysis of distribution of active power along the length of the three-phase inductor. Describes the main causes of deteriorating the uniformity of heating of billets. Highlights the issues of electro-magnetic compatibility powerful induction units with electricity supply system.

The Kotelnikov-Shennon theorem proves the possibility of data recovery from digital signal if the sampling frequency is the frequency of discrete elements is more or is equal to the doubled sampling frequency . This is true if sampling frequency has limitations. However, in real systems, with a tend to infinite value the effect of Aliasing is shown, which distorts the information. In this regard, the influence of discrete digital system introduces an additional error, which degrades the system specifications. The purpose of the paper is to analyze the impact of discreteness brought by an extrapolators of a zero order as a part of automatic control system on the system error.

The steady-state flow process of incompressible fluid to the system of production wells in horizontal reservoir of constant height and permeability is considered in this paper. There is a thin area in the reservoir with constant permeability $k_f$, which models highly permeable cracks or low permeability barrier. The characteristic of filtration process for various $k_f$ value is studied, well productivity index and the analytical expression for skin are defined.

The mathematical and computer model of heating network for Samara District heating system powered from Samara TPP is developed. The electro-hydraulic analogy based on two Kirchhoff's laws that are applied in the calculation of electrical networks is used.In contrast to known methods of mathematical modeling of hydraulic processes based on electro-hydraulic analogy, in this study we applied a method of automatic identification of the model which allows to perform close approximation to real network hydraulic resistance.This approach, despite the complexity of calculations, provides a model which differs from the actual heating system by not more than 3-5%, depending on the number of experimental data used in carrying out the identification. Performed research allowed to develop the recommendations for changing of the operation modes of heating systems as well as calculate the optimal plans for their reconstruction and the construction of new sites.

Various petrochemicals and refined products have been tested as a solvent for dissolution of asphalt, resin, and paraffin deposits in tanks for oil and oil products. Experiments have been carried out with tree different dissolution techniques, which is most likely industrially applicable. Basic guiding principles were formulated for selection of available and efficient solvent for the removing of asphalt, resin, and paraffin deposits. A possibility of involving dissolved deposits of asphalt, resin, and paraffin into refinery process have been considered as a step-ahead solution. Efficient technique of asphalt, resin, and paraffin deposits dissolution have been chosen and recommended for use in industry.

The influence of the modes of electron beam welding corrosion-resistant heat-resistant steel 06Cr15Ni6Mo1W1V1Nb1 9 mm thick on the formation of the welds and the tendency to form defects such as pores and slag inclusions was investigated. Welding was performed with technological lining thickness of 5 mm at different values of the beam current and the focusing lens current. To assess the quality of welding each of the samples was subjected to X-ray inspection, cutting and metallographic investigation with the definition of the parameters of welds, microhardness and the presence of defects. The obtained values of the welding parameters for a butt joint provide the required quality and size of the weld.

On the basis of community of mathematical model processors in electrical and non-electrical slow-response elements the possibility of principle expansion addendums of relativistic dynamics to electric circuit is considered. Technical capability of approximate realization of correlations by convention limit current value by means of inductor and voltage on the condenser by the use of negative-inductor and negative - condenser converter is shown.