Vestnik of Samara State Technical University. Technical Sciences Series

In the article the problem of interpretation output signals of artificial neural networks was considered in cases when softmax regression is used in them which calculated with heuristics often applied in practice. To use alternative multi-fold activation function in artificial neural network for objects categorizing is proposed. It is shown that output signals, that can be get in case of using the function, possible to be interpreted as probability of full group of events. Additionally, the form of distribution allows to estimate how precise the proposition is. With aim of developed artificial neural net that recognizes hand-written characters from 0 through 9 experiments were made that checks proposed approach.

The article is dedicated to a problem of corporations development. It describes two subjects - owners and manufacturers- the elements of a conceptual model for corporations development. The article gives us determinations of the subjects and main connections between them. The possibility of corporative development is shown as well and is based on partnership between the owners and manufacturers of material-energy resources. Transformation of corporations to partnership between owners of capital goods and working collective is suggested as the main model of further corporative development. The article also examines the principles of the gain distribution that prove the possibility and expediency of making partnership between owners and manufacturers.

In this article, a study is made of the existing dynamic models of the shape of the weld during arc welding used in the construction of automatic control algorithms.On the basis of the studies carried out, models of the shape of the weld during argon-arc welding were synthesized, taking into account the dynamic nature of the process of welding in real time. Under experimental verification, the transient processes of deterministic-statistical models and dynamic models with an aperiodic link of the first order were compared. An analysis of the error of the models over time allows us to conclude that they can be used in real welding production.

We examine issues of sinter quality management by means of changing the level of carbon in charge mixture. We show the main problems: low frequency of control of quality indicators and influence of carbon level in mixture on productivity which has to remain high. To solve the problem of sinter quality management we propose using a double-loop system of automated optimization on the basis of an optimum control system and a loop for cold mechanical strength stabilization. We consider issues of loops coordination and explore influence of their setting parameters on management efficiency. We assessed the effeciency by attainable productivity and cold strength levels. We show the need for a compromise between the mentioned indicators for the efficiency assessment when current disturbing frequency increases. We determined a correspondence between the frequency of control of cold mechanical strength index and the share of conforming sinter.

The method for measuring of radial clearance is considered. This method involves self-compensation of temperature impact on a single coil eddy-current sensor with sensitive element made as a conductor strip. The results of computational experiments based on the model of the electromagnetic interaction between an idealized sensing element of single-coil eddy current sensor with turbine and compressor blade tips are obtained. These results are given as quantitative evaluation of the influence of radial and axial displacements blades wheels in turbine and compressor. It's shown that the impact is doubled in turbines with a smaller range of variation in axial displacements. This is associated with an increase of the blade airfoil camber.

Samara state technical University, Department "power Supply of industrial enterprises". Samara, ul Pervomayskaya 18, KAB. 344. We consider the problem of determination of active resistance of asynchronous electric motors stator with squirrel-cage rotor according to the catalog data for the subsequent calculation of the other parameters of the equivalent circuit and construction of their mechanical characteristics. In the equivalent circuit of the induction motor contains six unknown parameters-resistance, known only nominal and catalogue data of the motor so the definition of one parameter with sufficient accuracy is an important initial step in the determination of other parameters. Catalogue data usually from different sources are specified with the rounding and low accuracy. Calculation of parameters of equivalent circuits of the motor power to five kilowatts is not difficult however, for high power engines the catalogue data errors have a significant impact on the accuracy of the calculations. In work the analysis of the catalogue data sources: power factor, efficiency, slip factor, ratio of maximum moment to nominal, and also the calculation of their average values, approximation and determination of their mutual conformity. As the result analytical expression for the determination of electrical losses in the stator and resistance of the equivalent circuit of asynchronous motors was get.

Discusses the use of the generators, tunable in frequency in installations of dielectric heating. The results of calculations of the parameters of the working chambers with a traveling wave and the radiation camera of the type in a single frequency and wide broadband modes. The principle of controlling the frequency of the radiation to compensate for changes in dielectric properties during heating of the dielectric. It is shown that changing the frequency of the microwave generator during the heating of the dielectric in the chamber with a traveling wave is achieved better than in the single frequency mode matching of the microwave generator with the operation of the camera for the duration of the heating and in the chamber of the radial type, it is possible to fix the depth of penetration of electromagnetic wave in the dielectric constant.

On the basis of the use of the twofold Laplace-Carson integral transformation, the problem of non-stationary heat transfer for a fluid moving in a cylindrical channel is divided into two independent problems - non-stationary and stationary, each of which is defined only in certain ranges of time and space coordinates. The non-stationary problem coincides with the problem of thermal conductivity for an infinite cylinder (heat transfer proceeds as if in a fixed liquid), the exact analytical solutions of which are known. To solve the stationary problem (the Gretz-Nusseltt problem), an integral heat balance method is used when using additional unknown functions and additional boundary conditions. Owing to the use of additional unknown functions, the Gretz-Nusselt problem is divided into two problems, in each of which the solution of the partial differential equation is reduced to the integration of an ordinary differential equation. The use of additional boundary conditions makes it possible, by carrying out the desired solution, the equation only at the boundaries, and obtaining its fulfilment within the region with an accuracy that depends on the number of approximations.

The paper presents the results of studies on the preparation of powder nitride composition is AlN-TiN systems «хAlF3+yNa2TiF6+zNaN3», «хAlF3+y(NH4)2TiF6+zNaN3», «хNa3AlF6+yNa2TiF6+zNaN3», «xNa3AlF6+y(NH4)2TiF6+zNaN3» (with different ratios x, y and z) in the mode of self-propagating high-temperature synthesis with the use of sodium azide precursors, halide salts of nitride elements. The final product is synthesized from all investigated systems, was a homogeneous mixture of three phases: aluminum nitride, titanium nitride and Na3AlF6. Na3AlF6 was a byproduct of the synthesis, which was unable to get rid of water washing of the final product. During the research it was found that the best output (and quantitative phase composition, the morphology of the product) is synthesized from the system «AlF3+3Na2TiF6+15NaN3» microfine (submicrocrystalline) nitride powder composition AlN (6%)-TiN (82 %)-Na3AlF6 (12 %).

The article presents results of study of the mechanical mixing and subsequent compaction of powder mixture, consisting of powder - carrier electrolytic copper (Cu) with particle size of 20...100 microns with nanopowder composition, modifier, of powders aluminum nitride (AlN) - 65 % and sodium hexafluoroaluminate (Na3AlF6) - 35 % with particle size of 100 nm, obtained by azide technology of self-propagating high-temperature synthesis (SHS). The mixtures, containing 2.5...5 % (mass) of the modifier, were investigated. The preparation of investigated powder mixtures Cu-AlN was performed by mechanical mixing in planetary centrifugal mill «Pulverisette-5» and in mill «Drunken barrel» within 60 minutes with speed 150 rpm/min and 45 rpm/min respectively. The chemical composition of the obtained powder compositions was investigated. Analysis of initial mixing of powder components was conducted. Some physical and technological properties of the obtained powder mixtures: particle size distribution, density, flowability and bulk density, were determined. The formation of ligature briquettes - nanopowder pseudo-ligatures of composition Cu-AlN with different contents of dispersed modifier carried out by uniaxial cold pressing in cylindrical mold on hydraulic press PSU-50 with pressing pressure 19...23 MPa. The dependence of the porosity of the briquettes from the pressure of pressing is determined. Microstructures pseudo-ligatures pressed at minimum pressure of pressing are presented. Nanopowder pseudo-ligatures (compacts) 25 mm diameter, height to 2 mm, weighing 2.5 and 5 g, with relative density 58…87 %, intended for subsequent input in aluminum melt with the aim of modification are received.

Comparison of next alternative methods of heating is given: resistance and induction. Indicates the effectiveness of co-design processes of deformation, heating and design construction of heaters. The problems arising at design and operation of high power inductions for preheating of big dimensions slabs are mentioned. At the same time results of the theoretical and pilot studies received when heating slabs of the industrial sizes are given. The reason of emergence of cross section effect is uncovered. The electrodynamics problem at induction heating of rectangular slabs is considered, especially from aluminum alloys. At induction heating at an industrial frequency of current attention is paid to electromagnetic compatibility of single-phase inductors with the system of power supply.