2011. № 46
Mathematics. Physics. Mechanics | |
In article realization analytical treatment heat-mass exchange extension - viscous fluid in tubula direct-flow reactor. get opportunity to take dependent quantities temperature, hydrodynamic phase-locked oscillator, and rheological dynamics characteristic. Determination limit overpatching phase-locked oscillator whose realize safe working conditions engineering equipment, mast avoid off-design conditions of job, and it will well be reflected on worker safety instrumentation. Keywords: heat exchange, analytical solution, eguations and heat exchange, complicated rheological fluid, thermal explosion, characteristic eguation, bifurcation |
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A new modification of algorithm for direct numerical simulation of dispersed admixture dynamics in heterogeneous flows is presented. Distinctive feature of this method is a combination of direct simulation of particles collisions using trajectory approximation and conception of probe particles. Keywords: multiphase flows; direct numerical simulation; discrete-element method; fullscale modeling; probe particles |
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. To implement the subsystems of planning operations of the spacecraft, located at a considerable distance from the earth one method of analysis and information forecasting by hierarchical clustering and model of the spacecraft behavior based on self-similar (fractal) patterns is introduced. This allows us to significantly increase the speed of information processing. We consider an algorithm for hierarchical clustering which are synchronized with the behavior model of the spacecraft. Generalization of behavior is self-organizing model called fractoid. Keywords: planning, hierarchical cluster, the fractal pattern; fractoid; self-organizing fractoid. |
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When the length of mathematical pendulum varies according harmonious law with small amplitude, linear and nonlinear oscillations of pendulum at resonance 1:2 are researched. It is shown that the non-linear change of time reduce the equation of linear oscillations to Mathieu’s equation. The approximate analytical solution of Mathieu’s equation at resonance 1:2 is obtained. The non-linear equation containing terms of third order is considered. Amplitude- frequency characteristic of resonance oscillations was obtained, it is shown also that amplitude of oscillations takes finite value as opposed to unlimited values of linear approaching. Keywords: parametric oscillations, resonance, stability of equilibrium, Mathieu’s equalization. |
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Aviation technics and technology | |
Experimental studies of flow patterns of the wings in the subsonic wind tunnel for a wide range of angles of attack, even before the flow separation. The possibility of control of flow separation by means of a localized vibrating element. In the experiment, we used the method of weight measurements and measurements of the pressure distribution through the drainage holes on the surface of the model. It is shown that, in the arrangement of small-size aircraft can be placed transmitters on the surface of the wing - a membrane embedded in the surface and can be placed in the fuselage emitters irradiating wing. Keywords: wind tunnels ofMAI, the model wings, flow separation, the sound emitter; |
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One of the most important task the aircraft design is estimate mass of the aircraft elements. Increased a tolerance, opportunity of using one method for the weight design, decrease outgoing of time and money form new requirements for methodic and soft in weight designing. Article describe the method of calculation the aircraft elements of construction with using the mathematical method of the artificial neural nets. The results of the project research are presented. Keywords: aircraft design; weight design; methodology of calculation; artificial neuron net; artificial intelligent |
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In this paper we solve the problem of synthesis of control algorithm light aircraft during flight Keywords: control algorithm, the dynamic equations, the functional synthesis of optimal control. |
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The problem of designing of three different structural elements operating under static loading has been analyzed. The similarity criterions have been assigned. The limits of applicability of the design calculations formulas have been defined. Keywords: designing, bar, longeron, spar, panel, similarity criterion |
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Results of working out of numerical model and data of a computational estimation of characteristics of random vibration of aeronautical engineering articles in the conditions of joint flight with the carrier are presented. Dependences for spectral characteristics and vibrational acceleration levels in various points of an article’s structure are received and zones of maximum levels of vibration for the articles placed on an external suspension of the maneuverable carrier are defined. Results of numerical experiments are compared by use of article’s dynamic models with various levels of complexity. Keywords: aircraft carrier, oscillations, finite element method, beam, shell, dynamic state, vibrational acceleration, stationary vibration, spectral density |
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The procedure and results of the of the stress-strain state’s numerical analysis of elements of an aeronautical engineering’s structure at dynamic loading in the conditions of joint operation with the carrier are presented. Working out of the final-element model of a structure with the account of a structural features and loading conditions is executed. On the basis of computational researches dynamic characteristics and the maximum stresses for a bearing surface of an aeronautical engineering are defined. Keywords: aeronautical engineering; load-carrying surface; damping; oscillations; dynamic analysis; vibration accelerations; vibration stresses. |
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An option of an automatic-programmed system of drift angle elimination is examined. This system allows raising the landing accuracy under the sidewind by shifting the trajectory beforehand and using the two final U-turns based on the signals of yaw angle or sidewind. Keywords: drift angle, sidewind, shifting the trajectory, final maneuver, yaw angle, side overload, glancing angle, directional (ground) speed |
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In this paper methodical technical approaches to the process of comparative appraisal and selection of aircraft appearance preferred embodiment from among alternative versions under development at the pilot project of preliminary design are expounded. In this Method the selection process is realized by means comparative appraisal of alternative versions as per effectiveness/cost parameter for calculations of which there are simplified analytical models. Keywords: comparison, selection, effectiveness, cost, criterion, modernization potential, typical operation |
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Space technics and technology | |
It is the technique of predicting the characteristics of future spacecraft observations in the technical systemof regionalmonitoring. The research results are effected for the projectinterms oftechnical and economiccharacteristics ofthe spacecraftobservations. Keywords: methodology, forecasting, performance, system, regionalmonitoringapparatus,monitoring, investigation, cost,number of cameras, linearresolution, the frequencyof observation |
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The task of identifying the parameters of the aircraft’s movement on the active part of the trajectory is characterized by several features associated with the presence of a limited amount of tracking data for individual sections of the flight. For the filtration studying an array of telemetry data containing the discrete values of the apparent velocity, the algorithm of filtering was developed based on discrete wavelet-transform. The technique of identifying the parameters of the aircraft’s movement was put forward on the results of telemetry in the absence of a priori data about the statistical characteristics of measurement errors and estimated parameters. Keywords: telemetry; identify the parameters of movement; mathematical model of the motion; the apparatus of the wavelet-transform; the filtering algorithm; methodology; accuracy of filtration measurements. |
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Aerospace propulsion engineering | |
In this article a technique of experimental acoustic constructions (AC) calculating properties determination both in surface layer and comb altitude direction was suggested. Analisis of native and foreign normative materials for AC specimen testing realization was carried out. Methods of testing were studied and specimen sketches for AC calculating properties were suggested. AC specimen calculating properties determination testings had been carried out for: - longitudinal tention in coating surface, - tension and pressing in comb cores altitude direction, - outermost coatings creep in reference to each other, - fatigue and damping. Keywords: accoustic constructions; construction safety assurance; sundwich-type construction; perforate coatings; multilayer coatings. |
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Thermal barrier coating (TBC) ceramic top-coats made from Y2O3-stabilized ZrO2 (YSZ) have been used successfully in gas-turbine engine applications for more than 30 years. YSZ derives its favorable performance from a combination of properties that include low thermal conductivity, high thermal expansion coefficient, and phase stability to relatively high temperatures. With advanced engine requirements of improved performance and increased durability, a new generation of thermal barrier coatings is needed that will provide greater insulation (lower thermal conductivity) and permit higher operating temperatures. Keywords: thermal barrier coating (TBC); vacuum-plasma coating; electron-beam deposition; oxide ceramic; columnar structure. |
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A typical composition of space launch vehicle (SLV) engine devices (ED) is under consideration. An interconnection between control hard and soft instruments for engine devices and ED effectiveness growth is shown. Stages of evolution of mathematic simulation instruments for SLV ED systems and processes are detailed. A conclusion about necessity of mathematic simulation instruments development as ED effectiveness growth base is formulated. The task to develop common mathematic simulation instruments complex for ED processes and control algorithms is postulated as basis to cut ED experimental verification duration and costs. Keywords: space launch vehicle, engine device, liquid rocket engine, mathematic simulation complex. |
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The description of the methods and complex of the mathematical models, offered for carrying out estimating calculation of the technical and economical performances of rocket-ramjet on solid fuels at optimization design parameters of aircraft are presented in this article.The algorithm of the matching of the combined action separate elements considered engine at different operating conditions its work are developed. Keywords: aircraft, rocket-ramjet on solid fuel, core, mathematical model |
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Theoretical engineering. Mechanical engineering | |
The rigid symmetric rotor dynamic stability in the elastic-damper sliding bearings to the influence of the disturbing forces of the lubrication layer and external disturbing rotor forces are examined. The design equations are obtained. Calculation results of the rotor dynamic stability with different variants of the elastic-damper sliding bearing and their analysis are presented. Keywords: rotor dynamic stability; elastic-damper bearings; disturbing forces of the lubrication layer; external disturbing rotor forces. |
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The experimental study of operating of sliding liquid bearing at various loads with failure of oil system for simulation abnormal mode of turbine engine gearbox is carried out. Dependencies friction coefficient of fluid bearing fr om velocity, temperature and time in the oil starvation mode is presented. The lim it values in the load mode of oil starvation is presented. Keywords: gas turbine aircraft engine, gearbox, sliding liquid bearings, abnormal modes, boundary lubrication, friction coefficient, materials of friction pairs. |
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Control systems | |
The problem of developing and implementing the control algorithm of light aircraft, which must fend off the occasional atmospheric disturbance, causing a deviation from the trajectory of the flight task. Numerical solution of two-point boundary value problem of the canonical system of the Pontryagin maximum principle Keywords: equations of motion of center of mass of the aircraft, the terminal optimizing functional Hamiltonian, the conjugate variable. |
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Instrument making | |
This article is devoted to numerical study and application aspects of the Mach-Zehnder interferometer (MZI) design. The MZI operating point position is studied with respect to waveguide topology and waveguide width with beam propagation method. Experimental samples of MZI based on numerical study results are fabricated. Operating point position of five various MZI topologies is measured with experimental set up. Comparison of numerical and experimental results is accomplished. Keywords: integrated optical phase modulator, Mach-Zehnder interferometer, operating point, asymmetric topology, lithium niobate, proton exchange |
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Technical cybernetics. Information technology. Computer facilities | |
Structurally-parametrical synthesis is one of the basic procedures at designing of various devices and systems. As a rule, this procedure is carried out manually because of complexity of its formalization. In article the technology of automation of structurally-parametrical synthesis on the basis of a method of the morphological box is offered, allowing essentially to accelerate realization of this procedure and to synthesize a projected object. Keywords: structurally-parametrical synthesis, morphological analysis, morphological box, systematic search |
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This document describes the process of gathering information about aircrafts, its transformation into digital form. The basic methods of transformation are presented: the discrete Fourier transform, fast Fourier transform (FFT), Walsh-Fourier transform, discrete Walsh transform (DWT). On the basis of marginal analysis, it is proposed to apply the fast Walsh transform procedure in sensors. Because of its simplicity the fast Walsh transform procedure allows hardware implementation, which is capable of carrying out the conversion in real time. Keywords: complex tracking of moving objects, the discrete Fourier transform, frequency function, fast Fourier transform, Walsh transform, the Rademacher functions, Hadamard matrix, fast Walsh transform. |
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In this paper we propose the methods and algorithms of the decision-making intellectual support in personnel control systems on the base of fuzzy neural networks. The automatic generation algorithm of knowledge base is developed according to the established criteria of fullness and minimality. The reduction of feature space on the base of the specialists’ expert judgment is produced. Keywords: control system; decision-making; intellectual support; fuzzy logic; neural networks. |
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Radio engineering. Electronics. Telecommunication systems | |
The article describes the essence of the adaptive algorithm handover in perspective of integrated communication networks and navigation, shall determine the composition and structure of the digital maps that passed in the mobile station to implement the proposed algorithm. Keywords: radio communication; the mobile; GSM; UMTS; radionavigation; cellular; adaptive algorithm; handover; |
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Material authority | |
Observed experiment thermal conductivity and thermal resistance properties of ZrzC-Zr2O2-, NbвС-Zr2O2-, TaC- Zr2O2- и HfC-HfO2-based on compositions allow to make a conclusion of great perspectives of application of Nanostructured composite materials based on high-melting metal carbides and oxides for air-cosmic objects, which work in range up to 2000ºC purposely to increase phisico-mechanical parameters and heat- and thermal resistance. Keywords: ultra high temperature materials; high-melting carbides; carbide oxide composite materials; heat resistance. |
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Economics | |
Mergers and acquisitions in air travel market, despite the economic crisis, is actively continuing. Airlines seek to restructure their business: many carriers are undergoing bankruptcy, the other using the union's assets are increasing their share both in the world and the Russian aviation market. At the same time the similar processes in domestic market have their specific character and peculiarities, the Russian aircraft building affects on them as well. Keywords: mergers and acquisitions; airlines; Russian avia assets specificity; aircraft building |
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This article provides a definition of the productive potential of an enterprise, deals with issues relevant to efficient use of the productive potential at enterprises for the production of switching equipment for aviation machinery (based on example of a KEMZ Concern open joint stock company), determines the goal of using the productive potential and lists the indicators for evaluation of efficiency of using human resources. Keywords: enterprise potential production, labor potential, production workers, efficiency. |
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The restructuring of enterprises of the aviation industry is aimed at preserving and developing the production, scientific and technical potential accumulated in the aviation industry for many decades. One of the main tasks of the restructuring process is the creation of an efficient organizational and methodological management system for the development, production and realization of products. Competent scientific approach to the creation of such system will make it possible to achieve the expected economic effect appearing in the positive dynamics of market value indicators of separate enterprises and, consequently, in the increase of the capitalization level of the aviation corporation and the industry in whole. Keywords: restructuring, reorganization, coast approach, market value, enterprises of the aviation industry, affiliated society |
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The article presents the features of the integration contours of the strategic, tactical and operational management of industrial enterprise. The features of constructing a system of goals and key performance indicators (KPI) of enterprise and related industrial and financial model of the upper level of abstraction on the basis of the developed system goals, which is used to predict changes in values of the KPI-indicators of enterprise and scenario analysis of the company. The article gives directions taken as a basis for constructing - Balanced Scorecard, the principles of the theory of automatic regulation and control, methods of system analysis. The features of the various tools of information-analytical systems, such as statistical analysis, simulation, fuzzy logic, knowledge management, and use these tools in the construction of Executive Dashboard, which is the main tool to support operational decision-making, focused on business strategy. Keywords: integration; control circuit; strategy, operational management, manufacturing and financial business model |
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In this article there has been made a great analysis of major development trends of personnel management system at aviation industry enterprises. It has been made by Open Joint Stock Company “Combined Aircraft Corporation” within the framework of development personnel strategy on long-term perspective. Keywords: staffing, personnel, aircraft manufacturer, strategy. |