Другие журналы

scientific edition of Bauman MSTU

SCIENCE & EDUCATION

Bauman Moscow State Technical University.   El № FS 77 - 48211.   ISSN 1994-0408

# 09, September 2013

Machine Building and Engineering Science

Application of laser tracking system in automatic MIG/MAG welding control
# 09, September 2013
DOI: 10.7463/1213.0628186
M.V. Shvarc, A.V. Maloletkov, R.A. Perkovskii
The paper proves a use of tracking systems for real-time control of automatic and robotic MIG/MAG welding. The basics of modern tracking systems based on the optical triangulation were provided. A review of recent applications of such systems in welding manufacturing was also presented. An adjustment algorithm, operation in the scanning mode and data logging were illustrated by the example of SLS050 («Meta Vision Systems» Ltd.) tracking system application. Critical analysis of the system was carried out. Pros and cons, application domains and requirements for the welding equipment to be used were determined. This paper also emphasizes further approaches to integration of SLS050 with automatic pipeline welding equipment.
A profilometry of the preparation of a joint for solving problems of geometrical and technological adaptation of welding equipment used in the automated methods of arc welding of tubes
# 09, September 2013
DOI: 10.7463/0913.0618953
E.A. Gladkov, Yu.O. Toloknov, P.S. Demidov
Effective methods of geometric adaptation of the welding equipment to anomalies in the geometry of the joint assembly in arc welding by applying servo system were proposed. The anomalies in the joint geometry of the assembly were described and their impact on the quality of welds was evaluated. The variant of a use of optical sensors based on the CCD sensor for the measurement of the profile geometry and spatial arrangement of the joint was also proposed in this paper. Technical solutions for protection of the optical sensor from heat and light effects produced by the welding arc were described. Principles of the correction of technological parameters depending on the geometry of profile anomalies and the spatial arrangement of a joint were described.

Constructional Material Processing in Machine Building

Electrochemical modification of surface properties of carbon fiber based on the polyacrilonitrile
# 09, September 2013
DOI: 10.7463/0913.0620998
I.S. Strahov, A.A. Gubanov, M.S. Ustinova, D.I. Krivcov, V.Ya. Varshavskii, T.A. Vagramyan, I.V. Plyuschii, Yu.V. Korshak
Electrochemical and subsequent chemical treatments of carbon fiber produced by two-stage thermal stabilization and carbonization of polyacrylonitrile fiber were used for modification of its surface to improve its adhesive properties with epoxy matrix. Electrochemical treatment initiates complicated physical and chemical transformations which lead to etching, lengthwise channels and cross-link formations between carbon filaments. Various conditions for electrochemical treatment of carbon fiber in water solutions of ammonium salts (NH4)HCO3/(NH4)2C2O4 were used to determine the optimal modes and to increase the tensile strength value of microplastics up to 10% compared to untreated carbon fiber samples. Coating the surface of carbon fiber with polymer layers by electrochemical polymerization was applied; this approach appeared to be an alternative and effective way for modification of surface properties.
Increasing efficiency of flat grinding by cup wheel’s end face on the basis of control of the heat-stressed state of a working zone
# 09, September 2013
DOI: 10.7463/0913.0606036
T.N. Ivanova
Flat grinding by cup wheel’s end face usually is more efficient than other types of grinding because many abrasive grains simultaneously take part in the process; this leads to the decrease in machined surface roughness. At the same time, due to a large area and duration time of contact between the face wheel and the detail, this particular type of grinding is characterized by high heat release rate. In order to achieve the required quality face grinding is usually conducted at reduced power. That is why determination of relations and patterns in the process of face grinding of flat surfaces, which influence the heat-stressed state of the working zone would allow to increase machining efficiency of flat details.
Experimental determination of drilling cutting forces based on dimensional analysis and the similarity theory
# 09, September 2013
DOI: 10.7463/0913.0598978
A.M. Guskov
This paper deals with the similarity theory and dimensional analysis for investigating cutting forces – particularly during drilling. Use of dimensionless groups allows one to obtain relations which are independent of unit systems, reduce the number of significant variables; it also helps to avoid influence of measurement bias on the dimension of physical relationships and ensure comparability of experimental results obtained under various conditions by different authors. Eleven dimensionless quantities for cutting process characteristics were proposed. Based on the experimental data for 3 types of drills, polynomial and power cutting laws for both axial force and torque were derived. Extension of those relationships to the case of vibrational drilling was considered; a method of applying existing relationships to obtaining of cutting laws in the form of dimensionless criteria was proposed.
Process analysis, sharpening and testing of cutters made of boron nitride
# 09, September 2013
DOI: 10.7463/0913.0598355
S.V. Grubyy, V.V. Lapshin
In this paper the authors consider a process of finish turning of work pieces made of hardened steel with cutters equipped with tool materials based on boron nitride such as cubic boron nitride CBN10 (SECO) and Dense Boron Nitride (DBN). An analysis was conducted, and a method for calculating parameters of turning hardened steel work pieces was proposed; these parameters are forces, cutting temperature, wear rate, magnitude of wear, tool durability and parameters of chip formation. In the experimental part of this study the authors describe a technology of precision sharpening of cutting tools made of DBN; the quality of sharpening was estimated. Test results of the cutters during the process of turning of cylindrical and end face surfaces along with boring a hole in a work piece made of 9HS HRC 60 steel are presented in this work. Results of a quality estimation of the machined surfaces are also given. The conducted studies confirmed effectiveness of the use of cutters made of dense boron nitride for precision machining of hardened steel.
The purpose of geometrical parameters of the tap’s cutting part during processing of non-continuous surfaces
# 09, September 2013
DOI: 10.7463/0913.0590761
A.E. Dreval', I.V. Ivanina
In this article the authors consider an analytical form of the pattern change in the total radial force in forming discontinuous threaded surfaces by using the generator cutting scheme (taps, dies, die heads, etc.). A modeling method for various configurations of surfaces for threading was proposed. The authors propose an engineering technique of design decision-making for tool’s working elements and of the purpose of geometrical parameters of the tap’s cutting part during processing of non-continuous surfaces. The possibility of eliminating agreement between peak load on the cutting tooth and the moment of its interaction with a non-continuous surface was investigated.

Power Machine Building, Metallurgical Machine Building and Chemical Engineering

Calculation of feasibility of super high compression in the piston internal combustion engine
# 09, September 2013
DOI: 10.7463/0913.0622287
R.Yu. Sakulin, I.I. Ahtyamov, V.A. Shayahmetov, P.B. Yakovlev
A feasibility of the four-stroke diesel engine YANMAR L-100C running under condition of the super-high compression ratio was investigated numerically in this paper. Computational model was created in the simulation modeling system “Albea” which was designed at the department of ICE of the Ufa State Aviation Technical University. Dependencies of brake efficiency on the different values of compression ratio of the investigated engine were calculated and presented in this work. It was discovered that growth of the compression ratio from 19.3 up to 30 led to the significant decrease in brake efficiency. In the meantime, decreasing of the compression ratio from 19.3 down to 12 – 15 led to the growth of brake efficiency, especially at partial loads.
Influence of micro-arc oxidation on durability of IC-engine’s piston
# 09, September 2013
DOI: 10.7463/0913.0606017
I.A. Butusov, N.Yu. Dudareva
This paper presents results of an experimental investigation of a possibility of increasing durability of IC-engine’s pistons by creating nanostructured coating at the surface of a piston skirt with the use of the micro-arc oxidation method (MAO). The authors describe a method for creating a hardened layer at the surface of a piston skirt with the use of MAO; they also give a description of experimental procedures for pistons under conditions of engine operation and results of those experiments. This work was carried out in order to increase durability of IC-engine’s pistons made of aluminum alloys; the obtained results could be used for increasing durability and reliability of IC-engines.

Transportation, Mining and Construction Machine Building

Analysis of dynamic characteristics of a transport vehicle with combined power installation and hydrostatic transmission
# 09, September 2013
DOI: 10.7463/0913.0602200
V.A. Korsunskii
In this article the author compares dynamic characteristics of a vehicle with both a usual and combined power installation which includes an internal combustion engine and flywheel energy storage; the comparison was carried out with the use of a developed mathematical model. Influence of power consumption of a flywheel on dynamic characteristics of a vehicle with hydrostatic transmission was estimated. Factors limiting power coefficients and possibilities of using combined power installation were established. The obtained results allow to optimize overall dimensions of the flywheel, control laws of its drive and the vehicle’s transmission.
Capacity regulation of screw compressors
# 09, September 2013
DOI: 10.7463/0913.0596092
I.V. Filippov
Nowadays various methods of capacity regulation are or may be applied to screw compressors (SC). This paper presents research results of two methods: changing rotation frequency of the driving engine’s shaft and restriction of air in the suction passage. Comparative analysis of the research results allows to select the most suitable method for any particular case. Exergy efficiency coefficient was chosen as an economical operation criterion; this coefficient allows to estimate the degree of thermodynamic perfection of the screw compressor quantitively, when using various regulation methods.
Dynamic loading of friction elements of transport vehicle transmissions
# 09, September 2013
DOI: 10.7463/0913.0593565
A.I. Taratorkin, V.B. Derjanskii, I.A. Taratorkin
In this paper processes of formation of dynamic loading were investigated; ways of improving durability of shrink disks of transport vehicle transmissions were justified. A hypothesis of destruction of these disks due to the impact of high-frequency perturbations produced by both an engine and a hydraulic torque converter was proposed; parametric resonance oscillation conditions were determined. Unstable zones for parametric oscillations were defined, using the Mathieu equation; need for filtration of high-frequency perturbations was determined in order to limit the parameter of modulation depth. Estimation of the influence of developed procedures on durability of shrink disks was conducted.
Development of an adaptive law of relay control of three-level damping of elastic damping elements of multi-wheeled vehicles’ suspension
# 09, September 2013
DOI: 10.7463/0913.0567756
M.M. Jileikin, L.R. Mardeeva, S.E. Semenov, M.A. Andreev
The required level of damping a multisupporting oscillatory system, as it is known, depends on the nature of the external impact. In this case, regulation of damping characteristics depending on the operation mode of depreciation systems is one of the main directions of further improvements. Direction of increasing the quality of primary control systems for suspension of multi-wheeled vehicles (MWV) with the number of axes more than three appears to be very promising. A mathematical model and calculation methodology of design parameters of a pneumohydraulic cushion with backpressure and three-level damping for controlled suspensions of multi-axis chassis were developed. An example of calculation of a cushion for MWV suspension with a 8x8 wheel formula and total mass of 60 tons is given. The adaptive law of relay control of MWV suspension system, namely the “inertial damper” adaptive law, was developed with the use of fuzzy logic methods.

Mathematics and Mathematical Modeling

Flow simulation around a thin plate using a modified numerical scheme of the vortex element method
# 09, September 2013
DOI: 10.7463/0913.0602362
M.E. Makarova, I.K. Marchevskii, V.S. Moreva
The Blasius benchmark problem dedicated to numerical simulation of a flow around a thin plate is considered in this paper. The laminar boundary layer was simulated using a modified numerical scheme of the vortex element method with tangent velocity components. This numerical scheme was implemented in POLARA software. Distributions of longitudinal and transversal velocity components over the boundary layer’s cross-section were obtained. Use of the modified scheme allowed to improve accuracy of determining the intensity of a vortex layer on the plate significantly at every step of the calculation. The obtained results appeared to be in good agreement with the analytic solution given by Blasius.
Choice of basis for simulation of ETL wire by the Galerkin method
# 09, September 2013
DOI: 10.7463/0913.0602290
O.A. Ivanova
A problem of building a system of base functions suitable for solving motion equations of a wire by the Galerkin method was considered in this paper. Dependence of the peak-to-peak amplitude of oscillations on the number of base functions was studied by a test example. Two sets of wire parameters were considered; wire motion is qualitatively different for these sets. Use of one base function in each direction is reasonable for a taut wire and it leads to an error less than 4 %. For a slack wire usage of not less than six base functions is required for correct simulation of wire motion.
Dynamically linearizable control systems and coverings
# 09, September 2013
DOI: 10.7463/0913.0601455
V.N. Chetverikov
This paper deals with systems that are reduced to linear control systems by composition of a dynamic feedback transformation with the change of variables. Such systems form the widest class of systems for which control algorithms were developed. An invariant description of algebra of vector fields which define linearizing dynamic feedback was obtained by methods of infinite-dimensional differential geometry. This result can be used for checking dynamic linearizability of particular control systems and in theoretical studies for creating examples of dynamically linearizable systems with certain properties or describing the whole class of such systems with a given dimension.

Aeronautical and Rocket Space Engineering

Calculating parameters of flow and acoustic noise for a tandem of cylinders
# 09, September 2013
DOI: 10.7463/0913.0602256
M.V. Kraposhin, I.N. Sibgatullin, S.V. Strijak
The goal of this work is verification of turbulence models and acoustic analogy for flow simulation and calculation of noise for a tandem of cylinders. In the scope of this work numerical results of flow simulation around a tandem of cylinders with different turbulent models were presented. Problem definition and computing methods were also defined. The RANS equations were closed with k-e, k-ω SST, SA turbulence model. Large eddy simulation was based on one sub-grid turbulence model equation. Curle’s acoustic analogy was also used. The computational method is based on the finite method algorithm. The calculation of aerodynamic coefficients of bodies was conducted with different grids and turbulence’s models. Comparison of the obtained results with the experimental results received also by the authors was carried out. On the basis of the obtained results recommendations on calculations of 3D cases could be given.
Problems of minimizing summary characteristic velocity required for maintenance and replenishment of satellite systems at non-coplanar circular orbits
# 09, September 2013
DOI: 10.7463/0913.0598333
A.A. Baranov, D.A. Grishko
This article describes cost estimations of summary characteristic velocity (SCV) required for replenishment of satellite systems at circular and near-circular orbits. TSCV costs optimization for maneuvering is based on using a parking orbit. All possible combinations of values of initial and final orbit parameters were investigated sequentially. The accompanying effects were analyzed; consideration of these effects allows to minimize SCV costs significantly. Analytical relations which determine a number of passive circuits at a parking orbit representing a compromise between time and SCV costs for coplanar flights were found. The obtained results could be used for minimization of temporal and energetic costs while designing and exploiting specified types of satellite systems. In addition, these results are applicable in exploitation of maneuvering space vehicles designed for collecting large-sized space debris.

Instrument Engineering, Metrology and Information-Measuring Devices and Systems

Study of linear aerial photosystems that are based on the photosensitive charge-transfer devices
# 09, September 2013
DOI: 10.7463/0913.0619654
Yu.G. Veselov, S.P. Gulevitch, A.S. Molchanov
A study of aerial photosystems that are based on the photosensitive charge-transfer devices was carried out in order to determine the linearity of their units. To estimate the linearity of photosensitive charge-transfer devices the authors used results of a specially developed technique of physical research, which is based on the construction of light characteristics and verification of the superposition principle. It was shown that a photosensitive charge-transfer device is a linear unit within a certain range of brightness. Width of this range was determined by the introduction of the notion - light latitude of a photosensitive charge-transfer device.
Photometrical equipment for determining the value of thermal decomposition of polymer materials during machining
# 09, September 2013
DOI: 10.7463/0913.0591230
V.M. Yaroslavtsev, A.N. Mirskov
This article presents a description of a functional principle, a structural scheme and an operation of the technological photometrical equipment designed to determine the time of origin of thermal decomposition and development in polymer composite materials; this decomposition appears during machining of such materials in modes with high temperatures in the area of chip formation and represents one of the major defects of machined surfaces. The proposed equipment developed in Bauman MSTU allows to determine the value of thermal destruction during machining without harming product integrity. This equipment could be used for studying influence of machining conditions on the value of decomposition, for in-process detection and for adaptive control of machining in order to provide the required manufacturing quality.

Informatics, Computer Science and Management

Hierarchical representation of a computer network on the basis of a Hopfield neural network
# 09, September 2013
DOI: 10.7463/0913.0630141
M.A. Basarab, S.V. Vel'c
The problem of hierarchical representation of a computer network for carrying out its multiscale analysis was considered. An original problem was reduced to the known set cover problem (SCP). Since this problem is NP-difficult, approximate heuristic techniques were useful for its solving. We proposed an algorithm based on the recurrent Hopfield neural network and its combination with the simulated annealing algorithm (so-called Boltzmann machine). A greedy algorithm was used for a construction of hierarchy levels. This approach was evaluated with a use of the test problems from OR-Library. Proposed approach could be used in the systems of traffic analysis and anomaly detection in computer networks.
Identification of linear dynamic elements using a frequency locus
# 09, September 2013
DOI: 10.7463/0913.0618917
V.I. Boevkin, V.M. Nedashkovskii, Y.N. Pavlov
This article deals with the identification method for a linear dynamic element with known transfer function using an experimental frequency locus with random measurement errors. A transfer function of an element was selected as a model. It was proposed to search for the solution to the identification problem in the class of hodographs, defined by the element’s model. Search for unknown coefficients of a transfer function of the element’s model was carried out by minimizing the proposed proximity measure of the experimental element’s locus and the model’s locus. As a result, the specified problem was reduced to a system of linear equations. An illustrative computing experiment for a second-order element showed that an error of the transfer function’s coefficients was comparable with the range of measurement errors of experimental samples of this element’s locus.
Statistical modeling of component supplies in the network of repair providers in auto industry
# 09, September 2013
DOI: 10.7463/0913.0615319
A.V. Baryshnikov, A.I. Chernyavskii, V.V. Borsch
The article deals with the statistical analysis of a database of component and spare part supplies of the network of repair providers in automotive industry. Tests of regression, variance, correlation, factor analysis and other methods of multivariate statistical analysis were performed. Some patterns of the order placement, allowing one to build forecasting procedures for sales volume in a more substantiated way were obtained.
Management of educational systems with a use of a multi-agent technology
# 09, September 2013
DOI: 10.7463/0913.0606440
E.I. Zakirova
Questions of introducing a uniform technology of the selection of students for master courses into the educational process were considered by the example of creating a multi-agent system (MAS). A system being designed would solve three problems: determination of an optimal specialization of master courses on the basis of analysis of the competence model of a bachelor graduate, classification of students by groups depending on the level of their motivation and individual training results in a bachelor degree course, and also formation of master’s educational route if a student has bachelor’s non-formed competences which are necessary for further training. The architecture of MAS was described. Functions and a method of  agents’ interaction were also presented.
Study of the spectral properties of LiveJournal’s social graph
# 09, September 2013
DOI: 10.7463/0913.0603441
P.G. Klyucharev, V.O. Chesnokov
In this paper we compute some characteristics of the spectrum of LiveJournal’s social graph and estimate the vertex and edge expansion ratios of this graph. We use the Power Iteration algorithm to compute first and second elements of the graph’s spectrum. The concept of application of the spectral graph theory methods to problems of social network analysis appeared to be very promising. Methods described in this paper could be applied to analysis of social networks, study of the social interactions between people and many other problems at the intersection of sociology, computer science and information security.
A modified cuckoo search method in the global optimization problem
# 09, September 2013
DOI: 10.7463/0913.0603388
N.N. Benza, A.P. Karpenko
In this paper we consider a global optimization problem and a method of Cuckoo Search (CS). CS method could be used for solving the specified problem. This method belongs to a new class of population based algorithms, which have been developed actively in recent years. In contrast with other known population based methods CS has only two free parameters. The goal of this work is to increase the efficiency of the canonical CS method. Several different modifications were presented in this work along with their software implementations; the canonical method was also implemented. Results of comprehensive performance study of proposed modifications by the example of a set of benchmark functions which revealed advantages over the canonical method were presented. One of proposed modifications was used for solving the existent practical problem of minimizing the expenditures on the manufacturing of high-pressure vessels. It was shown that proposed modifications provide a better value of the objective function in comparison with results obtained by other researches and also allow one to meet all restrictions.

Mechanics

Evaluation of effective thermal conductivity of composites with ball inclusions by the method of self-consistency
# 09, September 2013
DOI: 10.7463/0913.0601512
V.S. Zarubin, G.N. Kuvyrkin, I.Yu. Savel'eva
The method of self-consistency was applied to obtaining an estimate of the effective value of thermal conductivity of a composite with ball inclusions. This method was based on averaging of parameters of a perturbed temperature field in elements of a composite structure. The perturbed temperature field in inclusions and ball particles of the composite matrix was found by solving the steady-state heat conduction problem formulated on the basis of a constructed mathematical model of thermal interaction of these elements with a homogeneous material with an unknown coefficient of thermal conductivity. Quantitative analysis of the derived calculated relation was carried out to a sufficiently wide range of the defining parameters to verify reliability of the obtained estimate. The calculation results with respect to this relation are located within the interval between the lower and upper estimates which could be obtained from both a singular approximation of the theory of random functions and the dual variation principle of Hashin - Shtrikman.

Radiophysics

Simulation of absorption and dispersion processes of electromagnetic waves within the microwave frequency range in dispersed media based on wave optics
# 09, September 2013
DOI: 10.7463/0913.0623173
I.A. Damarackii, P.A. Trunov
This paper describes the interaction of artificial disperse systems with electromagnetic radiation within the microwave frequency range, which is based on the conditional division into sub-bands according to the character of interaction. For one of the sub-bands, a mathematical model was proposed that in the approximation of wave optics allows one to calculate the reflection and absorption characteristics of the system. Results of the calculations were also presented. A possibility of creating a dispersed system operating within the frequency range from 1 GHz (30 cm) up to 120 GHz (2.5 mm) was demonstrated. Moreover, its sizes (14 m) are comparable to the size of an object of military equipment, and the mass of the dispersed phase is only 3.7 kg.
Accuracy evaluation of modern computer programs for calculating objects’ effective echoing area
# 09, September 2013
DOI: 10.7463/0913.0623058
B.S. Lobanov, I.A. Damarackii, Yu.M. Mironov
A problem of computational accuracy of objects’ effective echoing area (EEA) using modern software such as CST Microwave Studio and «Analysis of radiolocation characteristics of complex shaped objects» developed in Bauman Moscow State University was considered. The authors tried to formalize accuracy evaluation procedure for these programs using characterization factors and mean-root-square errors between monostatic angle diagrams of EEA for some objects obtained with a use of the specified software and ones, experimentally measured. It was shown, that software had acceptable accuracy of ±5m2.

Optics

Diffraction nonreciprocity of counterpropagating waves in a ring prismatic resonator with a diffraction photomixer
# 09, September 2013
DOI: 10.7463/0913.0616142
S.I. Nazarov
This article deals with investigation of diffraction nonreciprocity of a ring prismatic resonator; in this case the diffraction nonreciprocity is conditioned by presence of a diffraction photomixer and a sharp edge diaphragm. Dependences of diffraction splitting on the photomixer’s location relative to the resonator’s axis at various sizes of a single-sided diaphragm with a sharp edge were determined by means of solving an integral equation of the ring resonator numerically. The author obtained relation between displacement of the photomixer relative to the resonator’s axis and size of the sharp edge diaphragm when there was no diffraction nonreciprocity. The derived conclusions could be useful for design and modernization of laser gyrometers with resonators formed by total internal reflection prisms.

Electrical Engineering

Differentiating transformers in tachometric devices of valve electric drives
# 09, September 2013
DOI: 10.7463/0913.0617210
V.A. Solov'ev
Use of transformers as differentiating elements of a tachometric device of a follow-up valve electric drive with a sine-cosine rotor position sensor of the electric motor was justified. A possibility of linearization of the tachometric device’s output characteristic by connection of balancing capacitors to secondary windings of differentiating transformers was considered in this work. Capacity of balancing capacitors was determined. The author proposes a method for analyzing output voltage ripple of a tachometric device with differentiating transformers and for determination of their relative amplitude. The results of experimental researches of a tachometric device with differentiating transformers are also presented in this paper.
Method of increasing operation speed of a step electric drive
# 09, September 2013
DOI: 10.7463/0913.0602179
A.B. Krasovskii
In this article the author considers a step electric drive with power supply of the motor by a controlled current inverter in which the basic operation mode is movement with a constant or slowly varying speed. Relatively quick dynamic behavior is required in short periods of time. A control algorithm ensuring speeding at the expense of short-term increase in its torque at the corresponding multiplicity of increase in a phase current of the drive was proposed for the specified variant of the step electric drive. A simulation model of the electric drive was developed in MATLAB – SIMULINK; this software helped to verify  efficiency of the proposed steering mode. It was shown that the considered algorithm is not effective for electric drives with considerable external damping. Results of the simulation were presented in a polynomial shape convenient for practical use.

Power Engineering

Excitement of turbulence fluctuations by a drift wave in plasma flows with non-uniform velocity
# 09, September 2013
DOI: 10.7463/0913.0620533
V.I. Hvesyuk, D.N. Karbyshev
In this work processes of formation of the drift turbulence in plasma with regard to existence condition of H‑mode were investigated for the first time. An effect of the drift wave of finite magnitude on plasma was considered. Influence of a poloidal plasma flow with linear velocity distribution vy(x) = Cx on a drift wave was also taken into account. A model was proposed and a program was developed for calculating the perturbations’ characteristics, which occur as a result of the specified influence. Dependencies of average values of plasma density fluctuations on the shear of velocity C and the growth rate of a drift wave γ were also obtained.
Calculation method for non-stationary heating of nano-structures
# 09, September 2013
DOI: 10.7463/0913.0617255
D.A. Vorob'ev, V.I. Hvesyuk
A non-stationary process of heat transfer in an insulated ordered multilayer nanostructure with specified initial temperature distribution was considered in the article. The structure consists of 1000 alternating layers of AlAs and GaAs. A heat transfer process model based on heat balance of a single layer was described in this paper. This model was used for heat transfer computations in ordered binary multilayer nanostructures for the first time. A process of heat transfer was investigated at different time moments, with different thicknesses of layers and heat resistances of interfaces. A case of deviation of periodicity in the structure was considered.
Numerical and experimental study of a supersonic separated turbulent flow and local heat transfer in a flat channel with sudden expansion.
# 09, September 2013
DOI: 10.7463/0913.0605814
V.V. Nosatov, P.A. Semenev
In this paper the authors present results of their numerical and experimental study of a supersonic separated flow and heat transfer in a flat channel with a sudden one-sided expansion at Mach number М  3 and with the presence of a turbulent boundary layer before separation. The numerical model was based on RANS (Reynolds Average Navier – Stokes Equations) with k-ω, k-ε and Spalart – Allmaras turbulence models. Computational fields of main gas-dynamic parameters in a stepped channel were also given. Comparison of numerical distributions with experimental data for wall pressure and heat-transfer coefficient downstream of a bench was carried out. A correlation analysis of the obtained velocity fields, wall pressure and friction, heat transfer coefficient in the area of separation and reattachment of turbulent boundary layer was also conducted.

Education Sciences

Competence model of professional elitism in the sphere of technology
# 09, September 2013
DOI: 10.7463/0913.0589246
A.P. Avdeeva
The author presents results of an empirical study aimed at implementation of a competence-based analysis of professional elitism in the sphere of technology. A competence model developed in accordance with the author's concept of professional elitism in the sphere of technology was proposed for the first time in this work. On the basis of the conducted competence-based analysis the main requirements to the level and quality of professional activities of elite specialists in the sphere of technology were revealed; these characteristics describe the focus and ability of elite experts of a technical activity profile holistically. The most important result of this work was creation of three basic clusters of competencies that reflect specifics of vocational elitism in the sphere of technology, including psychological peculiarities of the subject of work, socio-organizational interaction and interpersonal communication.
 
SEARCH
 
elibrary crossref ulrichsweb neicon rusycon
Photos
 
Events
 
News



Authors
Press-releases
Library
Conferences
About Project
Rambler's Top100
Phone: +7 (915) 336-07-65 (строго: среда; пятница c 11-00 до 17-00)
  RSS
© 2003-2019 «Наука и образование»
Перепечатка материалов журнала без согласования с редакцией запрещена
 Phone: +7 (915) 336-07-65 (строго: среда; пятница c 11-00 до 17-00)