Другие журналы

scientific edition of Bauman MSTU

SCIENCE & EDUCATION

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

# 12, December 2012

Machine Building and Engineering Science

Coordinate relationship of the medical robot – manipulator
# 12, December 2012
DOI: 10.7463/0113.0520630
E.P. Banin, O.P. Barysheva, A.F. Batanov, Yu.V. Bogdanova, A.M. Guskov, S.A. Kozubnyak, O.S. Naraikin, A.A. Pucenko
During surgical operations with the use of a robot–manipulator, control actions are managed by force effects in the area of the surgical operation. The constructional design of the robot is chosen according to the technological requirements for implementation of specific movements. It turns out that when a force is applied to the tool, displacement of the force application point can be non-collinear to the force vector. If interaction between a surgical instrument and the operation object can be reduced to a concentrated force, it is necessary to choose a beneficial robot configuration to avoid lateral offset. In this configuration the force vector must be aimed to the proper direction of the robot compliance matrix in the force application point. The proposed calculation method helps to construct a working configuration of the robot with respect to minimization of possible spurious derivation of the instrument from the requested trajectory.
Problems of development of stereotaxic guidance systems designed to control surgical instruments, illustrated by brain biopsy
# 12, December 2012
DOI: 10.7463/0113.0486770
Yu.V. Bogdanova, A.M. Guskov, I.V. Jidkih, O.S. Naraikin, V.A. Shurhai
A description of carrying out brain biopsy was examined. It is emphasized that one of the major problems is to position the instrument precisely and to maintain a safe trajectory while carrying out the operation. A disadvantage of traditional stereotaxic systems, apart from constructive disadvantages (long preparation and repeated operations have to be carried out in case of multi-target procedures), is that it doesn’t have the ability to observe the effectiveness of surgical manipulation in the target object in real time and, therefore, to reveal ongoing intracranial complications. Modern technologies which use robotic-manipulators allow to increase accuracy, speed and safety in high-precision operations simultaneously. The need for accuracy in positioning the instruments and automated support system are discussed in detail.

Constructional Material Processing in Machine Building

Factors affecting the accuracy of upsetting at stamping on a hydraulic press
# 12, December 2012
DOI: 10.7463/1212.0500313
A.G. Vyatkin, A.A. Vyatkin
 The process of cold upsetting of cylindrical work pieces on a hydraulic press was investigated. It was shown that errors of height and diameter of initial work pieces affected the accuracy of forged piece’s height in different ways. The degree of deformation of basic work pieces and relative sizes of forgings significantly altered the degree of influence of those errors on accuracy of forging.
About electrodiffusion wear
# 12, December 2012
DOI: 10.7463/1212.0486388
V.G. Kovalev, S.V. Kovalev
In this article the authors consider the basic questions of electrodiffusion physics. At cold plastic deformation, heat warms up the workpiece and the tool which are being machined, which, with different contact potential difference of the workpiece material and of the tool, generates an electromotive force (thermo-voltage) which usually increases along with increasing strain and temperature of contacting materials. The experimental data presented in this paper show that during the process of cold deformation of metals there occur thermocurrents from cutting (a related processing) which promote intensive tool wear. With the exclusion of their influence, tool life is increased by several times.

Power Machine Building, Metallurgical Machine Building and Chemical Engineering

Correction of regulator's dynamic characterisitcs in axial piston pump with electric proportional control
# 12, December 2012
DOI: 10.7463/0113.0516044
M.A. Andreev, S.E. Semenov
The article gives a description of the operating principle of the regulator in an axial piston pump with electric proportional control; a linear mathematical model of the regulator is also provided. It was shown that introduction of internal speed feedback could improve the dynamics of the regulator. The authors propose a way to implement this type of correction by introducing a nonlinear electric position feedback.
Thermal anchoring of wires in installation for investigation of low-temperature properties of materials
# 12, December 2012
DOI: 10.7463/1212.0486450
M.V. Kalyujnyi
This author considers thermal anchoring of wires with the use of a prototype installation for investigation of low-temperature properties of materials. A mathematical model of thermal processes is provided along with a numerical example according to the chosen mathematical model. The influence of self-heating of wires on the finite geometrical dimensions of the thermal anchor was determined.

Transportation, Mining and Construction Machine Building

Methods for stability analysis of a tracklaying vehicle’s curvilinear motion
# 12, December 2012
DOI: 10.7463/0113.0517531
M.V. Vyaznikov
This article considers the question of stability rating of a tracklaying vehicle’s curvilinear motion, considering the lateral drift. Methods of the theory of ordinary differential equations were used to determine stability boundaries of a dynamic model. The solution obtained by the numerical method with the specified step of integration is presented with a discrete sequence of points in a metric space. It was shown that the phase trajectory tends to an isolated limit set which, in the model, is a local integral manifold. Stability conditions of the limit set are emphasized. The developed algorithm of numerical stability assessment of solution of a system of equations is based on the Poincare-Bendixson theorem for differentiable manifolds. Also, the author considers an approach to solving the problem of motion stability on the basis of mapping the dynamic regimes on the parameter plane and defining the boundary of the domain of possible motion parameters of a tracklaying vehicle.
Research data on the electric vehicle with "Gazelle" chassis
# 12, December 2012
DOI: 10.7463/1212.0499839
A.N. Blokhin, A.M. Groshev, T.A. Kozlova, A.D. Yarjemskii, M.S. Seropyan
 The authors describe reasons for creating environmentally friendly vehicles, such as electric vehicles with a hybrid power plant. Specifications of the best known world analogues of electric LC vehicles are presented in this work. The authors consider features of the experimental model of the "NNSTU-Electro" electric vehicle created on the basis of "Gazelle" chassis developed and produced in the NNSTU. The results of theoretical and experimental studies of traction-speed characteristics and energy consumption when driving an NNSTU-Electro electric car in the urban cycle and steady motion are also provided in this article.
Procedure of choosing an optimal circuit decision in fuzzy conditions on the basis of multi-criteria analysis of alternatives with equilibrium and non-equilibrium criteria
# 12, December 2012
DOI: 10.7463/1212.0465867
M.M. Jileikin, M.R. Kalimulin, A.V. Miroshnichenko
One of the most important stages during formation of technical characteristics of a new vehicle is carrying out engineering analysis of the product, formation of circuit design which meets obtained values of influential parameters, realization of the draft design. Under these conditions, decision-making means choosing an alternative which simultaneously meets both fuzzy objectives and fuzzy constraints. The authors of the article developed a method of choosing an optimal circuit design which is characterized by selection in fuzzy conditions on the basis of a multi-criteria analysis of alternatives in equilibrium and non-equilibrium criteria according to the Bellman-Zadeh scheme. The analysis of design maps of possible realization of extra-light high Doppler wheeled vehicles for mountain operational conditions on the basis of domestic production units was carried out by the methods of fuzzy multi-criteria analysis and allowed to choose an optimal circuit design.

Mathematics and Mathematical Modeling

Construction of marginal probability density function of model parameters of cell population
# 12, December 2012
DOI: 10.7463/1212.0500575
M.S. Vinogradova
The author considers a mathematical model describing dynamics of the population of stem cells in standard laboratory culture conditions without food restrictions. For this model, point estimates of parameters and expression for their joint probability density function are known. They are derived on the basis of the Bayesian approach and Jeffreys invariat theory with limited samples of experimental data on values ​​of the state vector. The author found marginal functions of probability density parameters of the mathematical model and interval estimates for these parameters.
Use of simultaneous approximations to study arithmetic nature of values of hypergeometric functions
# 12, December 2012
DOI: 10.7463/1212.0500464
P.L. Ivankov
To study the arithmetic nature of the values ​​of hypergeometric functions with irrational parameters, effective Padé approximants of first or second kind are commonly used. In this case, the approximant of second kind (joint approach) are simpler and often produce more general results. In this paper the author proposes an effective construction of simultaneous approximations for hypergeometric functions of general form and their derivatives (including the parameter). With this construction, the corresponding module is estimated below by a linear form. Some of the parameters of the functions are irrational.
The number of points moving along a metric graph: dependence on the permutation of edges
# 12, December 2012
DOI: 10.7463/0113.0515440
V.L. Chernyshev, A.A. Tolchennikov
This article deals with a discrete problem of points moving along a metric graph connected with studying the statistic of Gaussian packets in a three-dimensional network. This problem arises when considering the Cauchy problem for the non-stationary Schrödinger equation. For an arbitrary finite compact graph-tree, representation for the number of points occurring in the initial vertex was obtained. By the example of one particular graph, the number of points moving along this graph was obtained as a sum of solutions for slack linear inequalities. The authors found the highest term of difference of the number of points moving along the graphs which were obtained from various assemblies of edges; the highest term of symmetric difference of the number of moving points was also obtained. 

Aeronautical and Rocket Space Engineering

Units for storing liquids in aviation hydraulic systems.
# 12, December 2012
DOI: 10.7463/0113.0513812
I.S. Shumilov, N.P. Solotenkov, T.G. Vinogradova
This article presents schema and constructions of hydraulic tanks of open and closed types used in passenger and maneuverable aircraft. The authors propose a technique of calculation of the necessary volume of fluid for hydraulic tanks of open and closed types; this method takes into account all flight regimes, including flights with a negative overload. The design procedure of the tank geometry which would have an optimal weight is also presented in the article, along with the scheme of open type tank pressurization with high-pressure dry air and reserve pressure boost from the cabin air-conditioner, the scheme of connection and design of the vent tank.
Analysis of factors affecting safety of flight of unmanned aerial vehicles (UAV). Causes of accidents of UAVs and methods of preventing them
# 12, December 2012
DOI: 10.7463/1212.0500452
S.P. Gulevitch, Yu.G. Veselov, S.P. Pryadkin, S.D. Tyrnov
The authors analyzed characteristics of flight operation of unmanned aerial vehicles (UAV) in the whole phase space of expected operating conditions. They consider basic aspects of the providing trouble-free use of unmanned aerial vehicles which exclude their uncontrolled fall to the ground and the resulting unintended damage to human life, health and their property on the ground. Factors that affect safety of flight of unmanned aerial vehicles were analyzed. The authors identified the causes and consequences of an air crash and proposed methods of preventing it.
Magnetic pulsing compression of high-speed metal elements created by an explosion in free flight
# 12, December 2012
DOI: 10.7463/1212.0496555
S.V. Fedorov, I.A. Bolotina
Accumulation of micro-damages as a result of intensive plastic deformation leads to decrease in average density of the high-speed elements which are created by an explosive crimping of shaped metal cladding. In order to compress such elements while testing meteorite shield withstandability it is proposed to use the longitudinal magnetic field effect on these elements; the magnetic filed is produced on the mechanical trajectory of elements before their interaction with the target. An installation scheme was developed for implementation of magnetic pulsing compression of high-speed metal elements created by an explosion. Influence of the solenoid’s length and intensity of magnetic field on the effect of compression of steel and aluminum elements is determined on the basis of numerical simulation. It was established that the induction of the influencing magnetic field should be equal approximately to 50 T for steel elements, and about 30 T for aluminum elements.
Determination of admissible variable for additional deployment of rotor-type solar sail
# 12, December 2012
DOI: 10.7463/1212.0493439
A.S. Popov, S.M. Tenenbaum
While deploying a rotary solar sail it may be necessary to increase its angular velocity (that is, to make its additional deployment). To achieve this, an additional torque is required (additional deployment torque). Due to fragility of the frameless structure it can lead to considerable displacements of the solar sail wings relative to the stiff part of the spacecraft, even to reeling the wings up on the spacecraft. In this paper the authors propose a mathematical model with two degrees of freedom for estimating the dynamic of the spacecraft with two-blade rotary solar sail with an external torque moment. The model is based on the nonlinear motion equations of two-element pendulum (the first pendulum simulates the stiff part of the spacecraft; second pendulum simulates the blades of the solar sail). This model allows to estimate an admissible torque considering the restriction on the deviation angle of the blades from the stationary position. Software for calculations was developed; dependence of additional deployment on the system parameters and character of the load (suddenness) was analyzed.
The influence of the azimuthal deviation ion plasma jet on the traction motor efficiency with anode layer
# 12, December 2012
DOI: 10.7463/1212.0483944
M.K. Marahtanov, D.V. Duhopel'nikov, S.G. Ivakhnenko, E.V. Vorob'ev, V.I. Krylov
The paper considers problems of changes in tractive coefficient of efficiency of a motor with anode layer by using different working substances. The authors obtained dependences describing the effect of the azimuthal deviation to the specified coefficient of efficiency, confirmed by the results of the experiment. The authors propose assessment criteria of using different working substances to increase tractive efficiency propulsion.

Instrument Engineering, Metrology and Information-Measuring Devices and Systems

Research of relationship between thermal conductivity of AlSiC composite material and formation factors
# 12, December 2012
DOI: 10.7463/0113.0517989
D.V. Graschenkov, B.V. Schetanov, A.V. Derov, K.N. Nischev, V.V. Eliseev, V.V. Berezovskii
A new relationship was developed to connect thermal conductivity of the AlSiC metal matrix composite (MMC) material with its sponginess studied by methods of equilibrium adsorption, optical and scanning microscopy and with chemical composition of its matrix alloy. It was shown that the process of obtaining AlSiC MMC was steady and reliable within the wide range of matrix alloys. However, direct dependence of heat conductivity on sponginess of AlSiC MMC was not established in certain cases. A basic manufacturing technology of heat-removing bases for AlSiC MMC was developed; further studies are aimed to development of an industrial technology. AlSiC MMC is applied in heat-removing products in the pulse power electronic industry and converter equipment. This is the first report which shows the role of sponginess of AlSiC MMC affecting its heat conductivity. The obtained data allow to formulate offers for improving heat conductivity parameters of MMC AlSiC.
Thermally isolated cells in designs of transducers of physical quantities made by an electrostatic anodic bonding of semi-conductor and dielectric elements
# 12, December 2012
DOI: 10.7463/0113.0517471
A.B. Borzov, K.P. Likhoedenko, V. Yu. Cygankov, Yu.N. Tinyakov, K.A. Andreev, T.A. Civinskaya
The authors consider the main method of creating thermally isolated structures of sensors of physical quantities made according to MEMS technologies, that is electrostatic anodic bonding. It was shown that the main reason for a small percentage of production of suitable thermally isolated structures manufactured by a method of electrostatic anodic bonding is unevenness of physical and chemical properties across the whole surface of semi-conductor and corresponding glass plates. The authors propose improvement of the anodic bonding method; designs for adaptations were developed for implementing this improvement. The proposed designs were manufactured and probed. Results confirming the possibility of increase in percentage of production of suitable thermally isolated structures of sensors of physical quantities with the use of the method of electrostatic anodic bonding were obtained.
Metrological support of phase-chronometric systems (part 1)
# 12, December 2012
DOI: 10.7463/1212.0514343
V.I. Pronyakin
This article presents an approach to metrological support of data measuring systems operating under field conditions of technical objects where there is a restriction on the access to their primary transducers due to repair intervals. Calibration intervals of measuring devices often don’t correspond to repair intervals. Under the circumstances, it is necessary to evaluate metrological characteristics of measuring channels while machines and mechanisms operate. In this case controlled parameters of the measuring channel must be independent of the features of the device operation and external actions. The proposed method is implemented with the use of multi measurement and measurement planning processes. The quality of the measuring process relative to the systematic error and dispersion using a test signal is also evaluated.
Study of nanostructured scintillator materials with synchrotron radiation source
# 12, December 2012
DOI: 10.7463/1212.0507344
Y.N. Litvak, M.O. Makeev, P.A. Mihalev, Yu.V. Panfilov, K.G. Potlovskii
The authors consider aspects of studying time characteristics of scintillation detectors. They propose using synchrotron radiation to excite scintillation measurements to ensure the decay time of scintillation detectors with subnanosecond time resolution.
Laser method of determining thickness of gold nanofilms on a quartz substrate, based on measurement of the transmittance
# 12, December 2012
DOI: 10.7463/1212.0507361
V.A. Gorodnichev, M.L. Belov, Yu.V. Fedotov
The article covers a laser method of measuring thickness of thin metal films on a transparent insulating substrate, based on the measurement of transmittance of a four-layer system "air (vacuum) - metal film - insulating base - air (vacuum)." Mathematical modeling results show that when measuring transmittance of a four-layer system "air (vacuum) - metal film - insulating base - air (vacuum)" at the wavelength of 515 nm, thickness determination of gold nanofilms on a quartz substrate is possible to a precision of  not more than 2% in the film thickness range  of 5 – 70 nm.
Laser fluorescence detection method of plant stress conditions caused by insufficient nutrients or contaminants in soil
# 12, December 2012
DOI: 10.7463/1212.0506199
M.L. Belov, O.A. Bullo, V.A. Gorodnichev
The authors analyzed fluorescence spectra of healthy vegetation and greenery under stress caused by lack of nutrients or presence of contaminants in soil. It is shown that use of fluorescence emission in the green or blue-green regions of spectrum and registration of fluorescent radiation in three narrow spectral ranges with central wavelengths of 680, 740 and 700 nm allows reliable detection of vegetation stress.
Monopulse location sounding method for natural fossils
# 12, December 2012
DOI: 10.7463/1212.0482683
M.L. Belov, A.M. Belov, V.A. Gorodnichev, B.V. Strelkov
In this paper the authors study capabilities of the monopulse optical location method of measuring reflection coefficient of natural fossils. It was shown that use of quadrature formulae and a regularization method allows to reconstruct spatial distribution of smooth varying reflectivity under the conditions of measurement noise in a wide coverage area of the optical locator

Radio Engineering and Communication

Developing an algorithm for extracting navigation data from GNSS signals
# 12, December 2012
DOI: 10.7463/1212.0496837
I.B. Vlasov, A.I. Gavrilov, M.T. Teran
The authors propose an algorithm for extracting navigation data from GNSS signals. Analysis of this algorithm was carried out with the use of mathematical simulation of a signal tracking system; data from navigation GLONASS (GNSS) space vehicles was used as input information. The authors provide curves displaying dependence of navigation message restoration quality on the signal to noise ratio (SNR) representing different methods of synchronization.

Informatics, Computer Science and Management

Identification of the structure and parameters of a chemical reaction model by a network operator method
# 12, December 2012
DOI: 10.7463/0113.0521994
A.I. Diveev, M.V. Semikov, E.A. Sofronova
The authors consider the identification problem for a chemical reaction model. The mathematical model in the form of a system of ordinary differential equations is developed on the basis of the given experimental data on the variation in time index of the concentration of substances that interact in the chemical reaction. To construct this model which clarifies the law of mass action a network operator is used. As a result of application of the network operator method, clarification of the law as a product of polynomials of the concentration of substances that interact in the chemical singlet oxygen reaction is obtained.
Construction of pseudo-random functions based on generalized cellular automata
# 12, December 2012
DOI: 10.7463/0113.0517543
P.G. Klyucharev
In this paper the author proposes a method of constructing block ciphers which is based on using generalized cellular automata. The Feistel network is used as the structure of the ciphers. Its combining function is a pseudo-random function based on generalized cellular automata; this automata’s graph is a Ramanujan graph. Statistical properties of the ciphers were studied by means of the NIST Statistical Test Suit. The empirical evidence showed that the ciphers have all necessary statistical properties and are indistinguishable from pseudorandom substitutions. There are a number of practical applications in the field of information security where ciphers constructed by means of developed method can be used.
WEB-modeling of oxidizing catalyst regeneration
# 12, December 2012
DOI: 10.7463/1212.0507309
A.V. Balaev, I.M. Gubaidullin, L.V. Saifullina
The authors consider mathematical modeling of complex catalytic processes - oxidative regeneration of coked catalysts. The relevance of the subject depends on the fact the regeneration of catalysts is important for the chemical, petrochemical and refining industries, as it is an essential step in any catalytic process. A virtual computer lab for calculations was developed. The authors propose a mathematical model of oxidative regeneration at the kinetic level, on an individual catalyst grain, in a still bed and a moving bed of contact material as well; methods for numerical solution of mathematical description are provided. The authors present an architecture of a designed virtual laboratory, the purpose of its main functional parts, a description of the developed software, the results of computer simulation and also physical and chemical findings.
Digital signal processing of the Doppler sensor of volume blood velocity with transient processes in microvasculature
# 12, December 2012
DOI: 10.7463/1212.0506267
N.S. Konnova
The author considers methods of mathematical apparatus and programmed mathematical tools for diagnosing biosystems conditions. This paper describes methods that can be divided into the following classes: a study of the general spectral pattern (Fourier - analysis, JMP); study of time-frequency characteristics of the signal (wavelet - analysis, scalogram, skeleton, selection of signal from noise); study of internal time series (methods of nonlinear dynamics, fractal analysis, R/S-analysis). Special attention is paid to methods of nonlinear dynamics, - in particular, to calculation of the Lyapunov exponent which allows to identify two types of irregularities: noise and chaos. The author describes interconnection of the Lyapunov spectrum and the entropy of dynamical systems. Also the author presents findings on persistence of the investigated physiological systems.
Method of guaranteed estimation of domain of attraction of a linear system with a convex feasible set
# 12, December 2012
DOI: 10.7463/1212.0506130
A.V. Gorbunov
The author considers the problem of estimating the domain of attraction for linear systems with constraints on the state. It is proved that the domain of attraction of the linear system with a convex admissible region is a convex set; the Minkowski function of the desired set and a method of its calculation are provided in this article. A method of guaranteed estimation of the required convex polyhedron is proposed, and an example is provided. The obtained results can be used to evaluate domains of attraction for linear systems with limited control.
Dynamic compensator in the form of an observer
# 12, December 2012
DOI: 10.7463/1212.0500592
A.V. Yurchenkov
The author considers constructing an observer for a discrete dynamical system specified in the state space, on the basis of an existing arbitrary compensator. In this paper the author describes a technology of bring any form of dynamic compensator to the Luenberger observer. Cases of compensators of low and high-order control object are considered. The author demonstrates validity of the principle of separation for the high order compensator. The results of the vector allow to obtain an estimation of the state vector of the control object from the state of arbitrary dynamic compensator after applying a special degenerate similarity transformation to its realization in the state space.
Stabilization of single-link manipulator with incomplete state measurement: feedback on the angular coordinate of the engine shaft
# 12, December 2012
DOI: 10.7463/1212.0500563
A.E. Golubev
In this paper the author considers the task of stabilization of a given angular position of a single-link manipulator when only the angular coordinate of the motor shaft can be measured. It was shown that synthesis of stabilizing control laws, as well as in the case when only the angular coordinate of the manipulator link can be measured, can be realized by the principle of distribution and bypassing the integrator in the observer. According to the results of the numerical simulation one can draw a conclusion about a similar quality of transient processes in the system with control found by means of bypassing the integrator in the observer, and the control which is based on the principle of distribution and linearization technique according to the state, provided that the observer is the same in all the cases and the initial data was considered. Possibility of applying the method of bypassing the integrator to stabilization can solve this problem also in the case of system disturbances and uncertainties. The results provided in this paper can possibly be applied in controlling technical systems with incomplete information about the state of the measured system.
Disruption of synchronization in the tracking system with delayed pseudo noise signal
# 12, December 2012
DOI: 10.7463/1212.0496490
A.A. Kovalchuk
The author analyzes the mean time till failure of synchronization of the discrete phase-locked loop system (PLL) in order to optimize parameters of the filter in the ring of delay control for the longest possible synchronization mode. The optimal value of the system parameter and the maximum reachable mean time till failure of synchronization was determined. An expression for the mean time till failure of synchronism, which is resistant to any limiting transition leading to reduction of the order of the system (which does not occur for a number of other methods of calculation) was obtained. The results are compared with different types of PLL systems of the second order.
Hybrid fuzzy neural model of intellectual data analysis for creating knowledge bases of soft expert diagnostic systems
# 12, December 2012
DOI: 10.7463/1212.0490457
A.S. Katasev, Ch.F. Ahatova
In this article the authors analyze the use of expert systems for solving diagnostic problems in many subject areas of human activity. The need for use of automated approach to formatting a knowledge base of the expert system based on the fuzzy neural network is substantiated. The need for developing a special hybrid algorithm based on the back propagation algorithm and the genetic algorithm in order to increase the efficiency of its learning is actualized. The authors provide a description of the developed algorithm. It was experimentally shown that application of this algorithm can improve the speed and accuracy of adjustment of parameters of membership functions of antecedents of fuzzy rules derived from teaching a fuzzy neural network. By the example of the task of medical diagnostic, efficiency of the proposed approach used for formatting knowledge bases of expert systems is shown.

Mechanics

Mechanical oscillatory systems with progressive motion. Possible forms of link connections.
# 12, December 2012
DOI: 10.7463/1212.0486791
S.V. Eliseev, Yu.V Ermoshenko, I.S. Sitov
The authors propose a technology for creating mathematical models of mechanical oscillatory systems with a chain structure and several degrees of freedom. Various descriptions of movement in different coordinates are considered. Some coordinates characterize relative motion. Nulling of such coordinates results in combining corresponding mass-inertia elements; hence, the system on the whole reduces the number of degrees of freedom by one. Generalization allowing to set several coordinates equal to zero simultaneously is also considered. Some examples are provided.

Electrical Engineering

Analysis of functional relation equations in the electrostatic gyroscope (ESG)
# 12, December 2012
DOI: 10.7463/1212.0506112
G.F. Drobyshev
A system of transcendental equations is investigated. On the basis of the spatial phase method of variation of the angular arbitrary orientation of the axis of rotation of the rotor in the electrostatic gyroscope functional relationship with relevant geometric angles with four axes is set. In order to increase angular orientation of the axis of rotation of the rotor to the range of 0 ÷ 360° the octant coordinate system is proposed.
Complex algorithm of sensorless control over gated inductor motor
# 12, December 2012
DOI: 10.7463/1212.0496400
M.V. Chavychalov
The authors consider a developed complex algorithm of sensorless control over a gated inductor electrical machine; the algorithm solves the problem of determining the initial position and starting speed of the rotor, sensorless start-up and the following operation at higher speeds. The author provides results of computer simulation and physical modeling of a sensorless start-up of SRM. The described complex algorithm can be used to improve reliability of gated inductor motors designed to work in harsh conditions.

Power Engineering

Comparative analysis of parameters and characteristics of different power plant schemes with an additional remote propfan
# 12, December 2012
DOI: 10.7463/1212.0511469
Yu.A. Ezrohi, S.M. Kalenskii, A.S. Polev, A.S. Drygin, P.A. Ryabov
The authors made an assessment of economic and mass-overall characteristics of a power plant in a long distance aircraft using cryogenic fuel. The scheme consists of two dual-flow turbojet engines and a remote propfan mounted in the rear fuselage the thrust of which compensates aerodynamic resistance of the fuselage. The authors examined five design maps of the remote propfan drive, including the schemes using a fuel cell power plant. They estimated characteristics of these schemes at different levels of power ratio of cruise engines and the external propfan. A comparative analysis of the mechanical, electrical and gas-dynamic drive of the remote propfan was made. The authors present conclusions on practical schemes of an integrated circuit power plant and their application.
Study of electromagnetic transients in circuits of small hydroelectric generator voltage
# 12, December 2012
DOI: 10.7463/1212.0506066
Yu.P. Gusev, A.A. Omokeeva
 Currently, operation experience of vacuum and gas-insulated circuit breakers substituting oil ones in the  chain "generator - transformer" is not enough. Therefore, in each case, installation of switches of a new generation requires an analysis of the switching processes. For conducting a research, mathematical models of the block scheme for low power hydro-plants and switches of various types among EMTP-RV were created. The authors estimated the levels of overvoltage occurring in switching by power-producing switches for various combinations of parameters of the main equipment unit; they analyzed the influence of parameters and places of installation of overvoltage protection. The main provisions of the research can be used by design organizations for reconstruction of low-power hydro-plants; in preparation of instructions for use of overvoltage protection when overvoltage is caused by commutation of vacuum switches in circuits of power-producing stations.
Appendix

Foreign Education

US Universities Launch Higher Education Initiative for Burma (Myanmar)
# 12, December 2012
Nine top US universities and colleges have formed an academic partnership to help Burma rebuild its higher education capacity, it was announced last week in the wake of a historic visit to the country by US President Barack Obama.Under an initiative launched by the Institute of International Education (IIE), the nine academic institutions will develop institutional partnerships with universities in Burma as part of the IIE’s International Academic Partnership Program (IAPP).
UK: Britain's First Profit-making University Opened
# 12, December 2012
Britain’s first profit-making university has been created as part of radical Coalition reforms to the higher education system.In a groundbreaking move, it was revealed that the College of Law, the country’s largest provider of legal education and training, had been granted full university status. It is the first private university to be established since Buckingham – officially a charity – was awarded the full title almost 30 years ago. But it the first time a profit-making organisation has been turned into a university. The announcement was made as part of a controversial Government plan to create more diversity in the higher education system.
 
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)