Astrakhan State Technical University

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Astrakhan, Russia

Astrakhan State Technical University is a university located in Astrakhan, Russian Federation. Wikipedia.

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Vasilev V.,Astrakhan State Technical University | Zhatkin A.,Astrakhan State Technical University
Refrigeration Science and Technology | Year: 2015

In a wind tunnel it is executed carefully planned regular and an experimental research of influence on heat aerodynamic characteristics of the basic geometrical parameters of rectangular ducts of plate-fin (PFT) exchange surfaces (HTS) with high value of finning Φ = 14. Criteria and graphic dependences are recommended for calculation of heat transfer and aerodynamic resistance of heat exchangers. The graphic method of definition and supervision of continuous change of values of the current estimations of a rational enhancement of convective heat exchange (RECH) and necessary at designing of heat exchanger duct values PFT HTS is offered within the limits of all area of realization of process RECH. The opportunity of reduction practically up to 2.78 times of volume and weights of a core of heat exchangers with interrupted ducts instead of smooth ones is proved.


Shikulskaya O.M.,Astrakhan State University | Shikulskiy M.I.,Astrakhan State Technical University
Journal of Physics: Conference Series | Year: 2017

Feasibility of the energy-information method use, both at a stage of conceptual design of control systems elements and at a stage of their outline designing is proved in the paper. It is shown that the use of the fractal approach to modeling of the physical principle of operation of sensors considerably increases possibilities of the power-information method, broadening the area of the synthesized technical solutions. The paper presents energy-information modeling of deformation of a flat membrane on the basis of the fractal approach. The offered approach unlike the classical approach allows taking into account anisotropic properties of semiconductor materials of a microelectronic membrane. The advantage of the provided method in comparison with other approximate methods consists in a possibility of transition from a stage of conceptual design to a stage of outline designing with the use of a single platform that considerably increases operational efficiency of designers.


Furtat I.,Russian Academy of Sciences | Fradkov A.,Russian Academy of Sciences | Tsykunov A.,Astrakhan State Technical University
International Journal of Robust and Nonlinear Control | Year: 2014

The problem of robust synchronization of a network of interconnected dynamical subsystems with a leader is considered. Each local subsystem of network is described by a linear time-varying parametrically and functionally uncertain differential equation. Only scalar inputs and outputs of local subsystems are supposed to be measured. A simple decentralized controller ensuring the tracking of the local subsystems by the leader under matching conditions is designed. The method is illustrated by an example, synchronization of the network with four nodes. Copyright © 2013 John Wiley & Sons, Ltd.


Furtat I.B.,Russian Academy of Sciences | Fradkov A.L.,Russian Academy of Sciences | Tsykunov A.M.,Astrakhan State Technical University
IFAC Proceedings Volumes (IFAC-PapersOnline) | Year: 2011

The problem of robust synchronization of a network of interconnected dynamical subsystems with a leader is considered. Each local subsystem of network is described by a linear time-varying parametrically and functionally uncertain differential equation. Only scalar inputs and outputs of local subsystems are supposed to be measured. A simple decentralized controller ensuring the tracking of the local subsystems by the leader under matching conditions is designed. The method is illustrated by an example: synchronization of the network with four nodes. © 2011 IFAC.


Tarasevich Y.Y.,Astrakhan State University | Lebovka N.I.,Ukrainian Academy of Sciences | Laptev V.V.,Astrakhan State Technical University
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2012

Numerical simulations by means of Monte Carlo method and finite-size scaling analysis have been performed to study the percolation behavior of linear k-mers (also denoted in publications as rigid rods, needles, sticks) on two-dimensional square lattices L×L with periodic boundary conditions. Percolation phenomena are investigated for anisotropic relaxation random sequential adsorption of linear k-mers. Especially, effect of anisotropic placement of the objects on the percolation threshold has been investigated. A detailed study of the behavior of percolation probability RL(p) that a lattice of size L percolates at concentration p in dependence on k, anisotropy, and lattice size L has been performed. A nonmonotonic size dependence for the percolation threshold has been confirmed in the isotropic case. We propose a fitting formula for percolation threshold, p c=a/kα+blog10k+c, where a, b, c, and α are the fitting parameters depending on anisotropy. We predict that for large k-mers (kâ†1.2×104) isotropically placed at the lattice, percolation cannot occur, even at jamming concentration. © 2012 American Physical Society.


Tarasevich Y.Y.,Astrakhan State University | Laptev V.V.,Astrakhan State Technical University | Vygornitskii N.V.,Ukrainian Academy of Sciences | Lebovka N.I.,Ukrainian Academy of Sciences
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2015

The effect of defects on the percolation of linear k-mers (particles occupying k adjacent sites) on a square lattice is studied by means of Monte Carlo simulation. The k-mers are deposited using a random sequential adsorption mechanism. Two models Ld and Kd are analyzed. In the Ld model it is assumed that the initial square lattice is nonideal and some fraction of sites d is occupied by nonconducting point defects (impurities). In the Kd model the initial square lattice is perfect. However, it is assumed that some fraction of the sites in the k-mers d consists of defects, i.e., is nonconducting. The length of the k-mers k varies from 2 to 256. Periodic boundary conditions are applied to the square lattice. The dependences of the percolation threshold concentration of the conducting sites pc vs the concentration of defects d are analyzed for different values of k. Above some critical concentration of defects dm, percolation is blocked in both models, even at the jamming concentration of k-mers. For long k-mers, the values of dm are well fitted by the functions dm ∞ km - k-α (α = 1.28 ± 0.01 and km = 5900 ± 500) and dm ∞ log10(km/k) (km = 4700 ± 1000) for the Ld and Kd models, respectively. Thus, our estimation indicates that the percolation of k-mers on a square lattice is impossible even for a lattice without any defects if k >≈ 6 × 103. © 2015 American Physical Society.


Furtat I.B.,Astrakhan State Technical University | Tsykunov A.M.,Astrakhan State Technical University
Automation and Remote Control | Year: 2010

Consideration was given to the reference model-based output-feedback adaptive control of a linear plant under a priori uncertainty of the parameters and order of the differential equation describing the dynamic processes in the control plant, as well as of lack of information about the relative degree of the transfer function. Solution relied on a modified high-order algorithm [1]. The resulting control system was dissipative in the large and made the plant output to follow asymptotically the reference signal to within δ. Results of modeling illustrating efficiency of the proposed control system were presented. © Pleiades Publishing, Ltd., 2010.


The damageability of hoisting cranes is still a prevalent problem because of nonoperational state loadings due to cranes' collisions with each other, and their impacts with the end stops (ES). The problem of dynamic loading of hoisting cranes in the process of a collision between cranes and the ES is still at the research level owing to the simplified approaches used. This article examines the problem of collisions between bridge cranes and the ES and the influence of such collisions on bridge cranes' metal construction. The following study uses a finite element dynamic model of16-ton double-girder bridge crane to simulate a collision between 16-ton double-girder bridge crane and the ES. As a result of the numerical simulation, a full picture of stress-strain state of a crane's metal construction has been obtained. It emphasizes the need to ascertain and standardize the boarders of maximum possible parameters of a collision between bridge cranes and the ES. © Faculty of Mechanical Engineering, Astrakhan.


Tsykunov A.M.,Astrakhan State Technical University
Automation and Remote Control | Year: 2011

Control problem is solved for a linear plant having mathematical model in the form of singularly perturbed differential equations with a priori unknown parameters. Control algorithms are proposed ensuring compensation of parametric and external perturbations with the required accuracy. In addition, conditions when the initial model allows for decomposing into fast and slow components are derived. The obtained results are numerically illustrated. © 2011 Pleiades Publishing, Ltd.


Furtat I.B.,Astrakhan State Technical University
Automation and Remote Control | Year: 2011

In this paper, a robust output control scheme is proposed for a linear dynamical network such that every its local subsystem is described by a linear differential equation with a priori unknown parameters. The network is subject to unknown exogenous bounded disturbances. The considerations are based on the introduction of a directed graph with vertices associated with the corresponding nodes of the network. An algorithm is proposed which ensures the synchronization of the network along with the compensation of the unknown disturbances with required accuracy. It is shown that the proposed scheme also remains valid for a network associated with an undirected graph. The theoretical results are illustrated via a numerical example of a network with four nodes. © Pleiades Publishing, Ltd., 2011.

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