Pozharskii D.A.,Don State Technical University
Journal of Applied Mathematics and Mechanics | Year: 2017
A system of two elastic equilibrium differential equations is studied in polar coordinates when Poisson's ratio is an arbitrary sufficiently smooth function of an angular coordinate and the shear modulus is constant. The elasticity modulus is also found to depend on the angular coordinate in this case. A general representation of the solution is proposed which leads to a vector Laplace equation and a scalar Poisson equation, the right-hand side of which depends on Poisson's ratio. When projected, the vector Laplace equation reduces to an elliptic system of differential equations with constant coefficients. Exact general solutions of the Laplace and Poisson equations are constructed in quadratures using a Mellin integral transformation and the method of variation of arbitrary constants. A contact problem for an inhomogeneous wedge is considered and the stress concentration at the vertex of the wedge is studied. © 2017 Elsevier Ltd.
Afanasieva N.,Don State Technical University
Archives of Acoustics | Year: 2017
The article aims to solve the problem of noise optimization of small wind turbines. The detailed analysis concentrates on accurate specification and prediction of the turbulent boundary layer noise spectrum of the blade airfoil. The angles of attack prediction for a horizontal axis wind turbine (HAWT) and the estimation based on literature data for a vertical axis one (VAWT), were conducted, and the influence on the noise spectrum was considered. The 1/3-octave sound pressure levels are obtained by semi-empirical model BPM. Resulting contour plots show a fundamental difference in the spectrum of HAWT and VAWT reflecting the two aerodynamic modes of flow that predefine the airfoil self-noise. Comparing the blade elements with a local radius of 0.875 m in the HAWT and VAWT conditions the predicted sound pressure levels are the 78.5 dB and 89.8 dB respectively. In case of the HAWT with predicted local angle of attack ranging from 2.98° to 4.63°, the acoustic spectrum will vary primarily within broadband frequency band 1.74-20 kHz. For the VAWT with the local angle of attack ranging from 4° to 20° the acoustic spectrum varies within low and broadband frequency bands 2 Hz - 20 kHz. © Copyright 2017 by PAN - IPPT.
Neydorf R.,Don State Technical University |
Neydorf A.,Don State Technical University
SAE Technical Papers | Year: 2016
The main difficulties of the mathematical models vehicles creation are defined by strongly nonlinearity of dependences which connect various variables their states and conditions of the movement environment. Most it belongs to aircrafts as aerodynamic interactions are characterized by essential nonlinearity up to discontinuity of variables and their derivatives. Creation process of these models is complicated by high-dimensionality, characteristic for the mechanical movement laws. Experimental creation of the mathematical models (MM) of such dependences is carried out by various mathematical methods of approximation of data. Universal remedies of the solution of the formulated task don't exist. Each of it possesses both benefits, and considerable shortcomings. In this regard the possibilities of a method creation of high-precision analytical approximations of the strongly nonlinear dependences using the analytical functions have been investigated. The Cut-Glue approximation (CGA) method for one-dimensional dependences is justified, and then this method is developed for approximation by functions of two arguments. In this method approximation is carried out by splitting of data into fragments similarly as in the method of piecewise approximation. Each data fragment is approximated by suitable function from which along its borders is cut out a fragment of this function. Cutting out of the function fragment is carried by multiplication its on the other nonlinear function with special characteristics. Properties of a nonlinear multiplier are such that in borders of a fragment of its value coincide with the approximating function, but are almost equal to zero in other range of definition. The received fragments are glued together in the united function which is model of the overall approximated dependence. The advantage of the Cut-Glue approximation method is differentiability of the mathematical models. It gives the chance to investigate functions analytically and to use their in MM of dynamics. In the offered article the possibility of application of a method for creation of nonlinear models of any dimension is proved and the ideology of accomplishment of all stages of "Cut-Glue" approximation is formulated. Tasks of optimum splitting experimental data into fragments, approximations of these fragments by analytical functions and their effective pasting in single in MM are formalized. The received result significantly expands a application area of a method and its opportunity in problems of mathematical modeling of dynamics of aircrafts and vehicles in general. Possibilities of optimal multidimensional "Cut-Glue" of approximation are illustrated by an example. © Copyright 2016 SAE International.
Kravchenko P.D.,Scientific Research Nuclear University |
Fedorenko D.N.,Don State Technical University
International Journal of Applied Engineering Research | Year: 2015
The article presents the design decisions according to the new concept of the transport equipment in the course of design in the device for working in special conditions by “The principle of a spider” and “The principle of an ant”. Also the direction of advanced technology of design process is discussed. Heuristic examples of search of the best technical solutions at design of load gripping and manipulating devices for work in extreme conditions are used. The article describes “The principle of a spider” when designing load gripping devices working with the additional weight which carries out the functions of the object capture while its vertical motion. “The principle of an ant” is described schematically; however it is quite enough for its use in design work. It is expedient to apply the presented examples at design of load gripping and manipulating devices for heavy and atomic power engineering, for radioactive equipment dismantling, for work in emergency conditions such as earthquakes, fires, floods, consequences of military operations during rescue and emergency recovery operations. The presented examples show the direction which can provide inventive examples with simple and reliable engineering decisions. © Research India Publications.
News Article | November 24, 2016
An Extraordinary Debut from a Russian Author Who Writes in English is Soon to be Released "One-Two" is a psychological drama, the main events of which unfold in the 1980s and 1990s in Russia. The novel reflects on how difficult it is to be a human and how important it is to stay human until the end. London, United Kingdom, November 24, 2016 --( Eventually, fortune smiles on them, by seemingly opening up the door to happiness: a separation surgery that can theoretically be performed in the capital. Thus begins a journey fraught with difficulties and obstacles for the sisters. Will they be able to get past the wall of public cynicism, together with the internal conflicts they have among themselves? Will they find a justification for their existence and learn to accept it? The search for the answers to these and many other questions constitutes the essence of this novel. About the Author: Igor Miroshnichenko (born 12 March, 1977 in Rostov-on-Don, Russia) is an English-language writer, novelist, and essayist; he writes under the pen name Igor Eliseev, his mother’s maiden name. Igor graduated from the Don State Technical University, where he studied engineering procedure, in 1999. He also studied at the Moscow University of Industry and Finance, graduating in 2009 with a degree in the management of commercial activities. He first tried his hand at writing sketches and scripts for a radio show. He also found himself particularly drawn to portrait and fashion photography. Some time later, he became one of the most in-demand photographers in Moscow. His photos brought him a lot of attention and a taste of financial freedom, but ultimately, literature remains his true and only calling. Igor Eliseev began his literary activity in 1999 with a number of short stories, essays and a film script. Later, the plot of the script developed into a literary novel – the most important project of his life and one that has not yet been completed. In 2015, however, he finished his second novel, which, by a twist of fate, became his debut novel. One-Two, a book that is dedicated to the memory of his mother, tells the story of two conjoined sisters born in the era of the collapse of the Soviet Union. He has been interested in oriental martial arts ever since he was a child and practices Judo, Karate, Jiu-Jitsu and Chinese Wushu; he worked as a martial arts instructor for several years. Review copies are available upon request. Title: One-Two Author: Igor Eliseev Publisher: Glagoslav Publications Language: English ISBN: 9781911414230 Extent: 240 pages Format: paperback, hardback, e-book London, United Kingdom, November 24, 2016 --( PR.com )-- Summary: Two conjoined babies are born at the intersection of two social worldviews. The girls are named Faith and Hope. After spending their childhood in a foster home and obtaining a basic education, they come to realise that they are different from other people in many respects. The problems of their upbringing are only made worse by the constant humiliations they suffer at the hands of society.Eventually, fortune smiles on them, by seemingly opening up the door to happiness: a separation surgery that can theoretically be performed in the capital.Thus begins a journey fraught with difficulties and obstacles for the sisters. Will they be able to get past the wall of public cynicism, together with the internal conflicts they have among themselves? Will they find a justification for their existence and learn to accept it? The search for the answers to these and many other questions constitutes the essence of this novel.About the Author:Igor Miroshnichenko (born 12 March, 1977 in Rostov-on-Don, Russia) is an English-language writer, novelist, and essayist; he writes under the pen name Igor Eliseev, his mother’s maiden name.Igor graduated from the Don State Technical University, where he studied engineering procedure, in 1999. He also studied at the Moscow University of Industry and Finance, graduating in 2009 with a degree in the management of commercial activities.He first tried his hand at writing sketches and scripts for a radio show. He also found himself particularly drawn to portrait and fashion photography. Some time later, he became one of the most in-demand photographers in Moscow. His photos brought him a lot of attention and a taste of financial freedom, but ultimately, literature remains his true and only calling.Igor Eliseev began his literary activity in 1999 with a number of short stories, essays and a film script. Later, the plot of the script developed into a literary novel – the most important project of his life and one that has not yet been completed. In 2015, however, he finished his second novel, which, by a twist of fate, became his debut novel. One-Two, a book that is dedicated to the memory of his mother, tells the story of two conjoined sisters born in the era of the collapse of the Soviet Union.He has been interested in oriental martial arts ever since he was a child and practices Judo, Karate, Jiu-Jitsu and Chinese Wushu; he worked as a martial arts instructor for several years.Review copies are available upon request.Title: One-TwoAuthor: Igor EliseevPublisher: Glagoslav PublicationsLanguage: EnglishISBN: 9781911414230Extent: 240 pagesFormat: paperback, hardback, e-book
Stanislav M.,Don State Technical University
Communications in Computer and Information Science | Year: 2016
Despite the growing number of different database and storage technologies, relational databases still support significant percent of internet and intranet applications due to their effectiveness in processing complex queries and capabilities to provide data integrity in concurrent data access.Most of modern relational DBMS develop their concurrent access models to meet the requirements of transaction consistency, but at the same time they lack tools that provide usability in complex scenarios of concurrent data processing, that require storing and retrieving multiple versions of the same tuple.This paper describes the high-level framework to manage multiple co-existing versions of data tuples, and to support complex workflows of concurrent data modifications, including “branched” versioning.The different aspects of design and implementation of such a system are discussed. © Springer International Publishing Switzerland 2016.
Neydorf R.,Don State Technical University
SAE Technical Papers | Year: 2015
The solution of the both synthesis and implementation problems of high-rapid rates control laws is extremely important for the development of automatic control systems of the aircraft. This is due to the high speed of such vehicles. Along with this, it is imperative that control laws provide that system is asymptotically stable, as the basis for the reliability of their controlled motion. Another important objective of the method of synthesis of control laws for aircraft is compulsory compliance with strict limitations on the values of control inputs at the actuation devices. It is equally important that the control laws provides limitations on the state variables of aircraft, such as velocity, acceleration, etc. Pontryagin's maximum principle is aimed at solving such a time-optimal problem with the limited command variable. However, both the mathematical formalism of this principle, and the mathematical formalism of the methods based on this principle don't provide a solution of the class described tasks. The problem is that, despite the fundamental theoretical validity of these methods, they don't provide robustness synthesized control laws. Robustness is understood here as the insensitivity of the properties of the control system to small variations in the properties of the control object. The reasons for this phenomenon are known. They are as follows: the asymptotic properties absent in positional control, maximum speed law is defined only within a given time interval, the stabilizing feedback is absent. As a result the inadequacy of the dynamic properties of a managed object and calculated data can lead to a complete loss of the control system quality. The essence of the proposed approach consists in influencing the change of the derivatives of the state variables, which form a system of phase coordinates. Each derivative of the state variable is formed by a special non-linear law. These laws impose a number of requirements: the derivative of the phase coordinates is limited, its rate of change is close to optimal for the designated limit, the law of its change is asymptotically stable. In other words, the state-space of the control object form specific invariant manifolds. These manifolds are formed by specially synthesized control law so that their properties are determined by the above requirements. Mathematically varieties are generated by nonlinear functions of the right sides of the system of differential equations of state of the control object. Structures and function parameters form the mathematical model of the control law. The resulting control action (signal input) sequentially generates the processes of change of phase coordinates in such a way that directs the state variables of the system on the given invariant manifolds. Formed diversity determine the dynamics of the controlled system. They in aggregate form its attractor, which meets the following properties: near-optimal performance, bounded of phase coordinates and asymptotic movement. The procedure of successive synthesis of invariant manifolds is given can be implemented for objects that have a mathematical model in the form of the Cauchy problem with the so-called "triangular" structure. For such a model is a characteristic that every i-th state variable of the system, which has the order of "n" and "r" of the control inputs, depends only on the state variables with index not greater than i + 1. In this case, any derivative of the state variable may depend on only one control input, and the n-th derivative is necessarily dependent on one of these inputs. This result is very important for the practical problems of management of working bodies of aircraft. For them, the control speed is a critical factor in the quality of flight and stability and robustness is a critical factor in the reliability of automatic control. Application of the proposed method is illustrated by the example of the construction and study of the automatic control system of the device controlling airship. Copyright © 2015 SAE International.
Neydorf R.,Don State Technical University |
Sigida Y.,Don State Technical University
SAE Technical Papers | Year: 2014
The paper formulated and solved the problem of investigating the traction and power characteristics of air-screw propulsor for airships. The study is performed by constructing a mathematical model relating the steady-state values of the shaft power and traction on the axis of the screw with the velocity of rotation and the actual velocity of the aircraft. Proved design scheme selection of computer simulation of aero-and thermodynamic processes occurring during rotation of the airscrew. Describes plan developed under the experimental task, providing variation in the basic parameters of the airscrew, motion parameters and flight environment The results of computer modeling of the interaction of the airflow with the airscrew at various combinations of these parameters. Results are shown in tabular and graphical form and as a mathematical model of the studied airscrew. Importantly, by developed and tested the method can construct mathematical models of airscrew propulsors any specific structures and geometrical parameters. This result is extremely important and useful for solving problems related to the selection, design and optimization of airscrew propulsors of airships and other aircraft with airscrew propulsors. These results are important for the development of motion control systems aircraft. Copyright © 2014 SAE International. © 2014 SAE International.
Glebov V.V.,Don State Technical University
Procedia Engineering | Year: 2015
This paper proposes a novel process for electrochemical engraving of metals without a need for stencils and photolithography. It dwells upon the features of receptions of electrodeposition films on a semiconductor tool electrode for electrochemical machining. The analytical equations to calculate the necessary thickness of a film are obtained. The technique of drawing films by thermal transpiration on vacuum plant VUP-4 is observed. The authors study a technology of making and designing the photo-active electrode tool, based on Cu/Si structure. The electrical and optical properties of a semiconductor thin plate have been investigated. The paper analyses the results of electrochemical machining by electrode tools with various thickness of an electrodeposition film. The theory and method of making, experimental results and an application of the semiconductor tool electrode are presented in this paper. © 2015 The Authors. Published by Elsevier Ltd.
Galushkin N.,Don State Technical University |
Yazvinskaya N.,Don State Technical University |
Galushkin D.,Don State Technical University
International Journal of Electrochemical Science | Year: 2014
In this study, it is proved that for batteries, the following empiric equations: generalized Peukert's equations, porous electrode equation, and probability integral describe the changes in the batteries' capacitance inthe case of a complete range of change in discharge current with the same parameters, regardless of the capacitance of the batteries under study. Meanwhile, Peukert's equation is true only from the point of inflexion of the experimental curve C(i) infinitely © 2014 by ESG.