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  • Stiff problem with the exponential nonlinearity for testing of mathematical modeling systems and circuit simulators

    The improvement of methods of electronic devices simulation is currently ongoing, so development the tests for these methods is the actual task at the present time. The goal of this paper is to develop the original test problem for efficiency assessment of numerical methods of ordinary differential equations solving and methods of numerical analysis of transients in electronic circuits and systems. The test problem is presented as mathematical model and electronic circuit too. Test problem and technique of estimation of numerical analysis algorithms’ accuracy proposed in the present paper can be used in circuit simulators and in computer mathematics programs to test both known and new simulation methods for electronic circuits and systems with various dynamics, including stiff and/or nonlinear circuits.

    Keywords: numerical methods, electronic circuits, transient analysis, ordinary differential equations, stiff systems

  • Multilayer 1d-periodic absorbing structures in the optical range

    In the present work a new trends in the development of absorbent materials are described. The results of calculation of scattering and reflection patterns for multilayer structures are presented. Parameters of the structures with highest absorption are evaluated. Analysis of obtained theoretical calculations is presented.

    Keywords: resonance absorption, metamaterials, plasmons, nanophotonics, nanostructures, reflectance

  • Algorithm and its program realization to control the hue contrast of digital images

    Graphic information carried by hue contrast is actualized, mathematical description specificity of hue as the basic colour characteristic is investigated, theoretical bases of hue contrast control are stated, original algorithm and program for images hue contrast control are described, resolution of the offered method is experimentally estimated, scope of the created software product possible applications is outlined, efficiency of its application in expert problems is shown.

    Keywords: graphic information, hue contrast, contrast control, algorithm and program realization, latent images

  • Optimizing sorting line woodworking enterprise through the use of dual-mode operation

    mathematical models, optimizing the cost of sorting of wood, provide a rationale for dual-mode operation sorting line woodworking enterprise

    Keywords: sorting line, round timber, mathematical models, forest drives

  • Investigation of diffraction of electromagnetic pulse on the slots Fresnel screen system

    The problem diffraction H-polarized electromagnetic pulse is reduced to the solution of the integral equation. Singled and analytically transformed into a special part of the integral equation. It transformed the integral equation applied collocation method for solving the spatial coordinate. Found near field and the results of calculations of diffraction of electromagnetic pulse.

    Keywords: Fresnel diffraction, electromagnetic pulse, collocation method, a near field

  • Non-reflecting optical grating in the new plasmonic materials

    The present state and development trends of plasmonic materials. The results of the calculation of scattering and reflection diagrams nanostrzhnyah of ZnO. And the prospects for the use of anti-reflective optical lattices.

    Keywords: non-reflecting grating plasmonic materials, nanophotonics, nanostructures, reflectance

  • Solution of a plane contact problem by finite element method

    "This article provides a solution of the plane contact problem with the use of a finite-element method. It presents the algorithms to determine the “node – response surface” contacting pairs through method of minimal penetration of contacting bodies. The article also contains the algorithm of rapid formation of the global stiffness matrix, taking into account the changes of the connections between mesh nodes for each iteration of solving in the Mathcad software."

    Keywords: solution of the contact problem, flat stress strain state of the finite element method, Mathcad

  • Greening the individual units of Rostov thermoelectric plant-2

    With the safety position and the environmental and economic feasibility of perspectivity renunciation of the use of imported liquefied chlorine (substance of 2 hazard class) and replacing it with an electrolytic solution of sodium hypochlorite (4 hazard class), produced by on-site consumption. Hydrogen, which is a waste product , is thus partially (15-20%) to reduce the need Rostov TEP-2 in this matter and to provide a corresponding reduction in energy and economic costs.

    Keywords: liquefied chlorine, sodium hypochlorite, hydrogen, emergency, chlorination plant, hydrogen generation, energy efficiency, resource conservation, safety

  • Strength assessment of reinforced concrete slabs for punching

    The article analyzes the calculation of the punching shear slab structures according to the recommendations of SNiP 2.03.01-84*concrete and reinforced Concrete structures. It is shown that the existing method of calculation gives overestimated the bearing capacity of floor slabs in bezrigelny frame systems. In order to establish the bearing capacity corresponding to the constructive decision is expected by calculation to determine the angle of the pyramid pushing.

    Keywords: extrusion, dowel effect, bezrigelny frame, preopera area, bearing capacity, punching the pyramid, technological hole, slab, reliability, rebar, concrete

  • The analytic numerical solution of the plane contact problem with termal creep of main material

    The article contais numerical analytical solution of the contact problem with termal creep of main material, based on the limited precision of machine arithmetic and practical significance of the result. A solution of the 2nd kind Volterra integral equation , which is the main task of resolving equations is made by replacing the integrand function and the introduction of "conditional indefinitely". The article contais analysis of the behavior of the function with all changes.

    Keywords: "solution of the plane contact problem numerical solution material termal creep"

  • Using the finite element mesh, created by GMesh, for calculations in Mathcad

    "The article treats the issues of data exchange between Mathcad and Gmsh. To solve this problem built-in and predefined functions are used in Mathcad without recourse to UFI tools. The solution proposed in the article is connected with importing a mesh with a complex topology into Mathcad for further processing with the use of numerical methods. The solution involving a partially automated transmission of the results of calculations in the nodes of spatial mesh cells for further visualization is also considered in the article."

    Keywords: visualization of numerical results, transfer mesh with complex topology, Gmesh, Mathcad

  • Vector-scalar characteristics of structural noise in building constructions

    In the various methods of non-destructive testing, which working with the deformation fields, diagnostic accuracy is largely dependent on the intensity of structural noise caused by small-scale irregularities of building structures. In this paper we investigate the effectiveness of using a vector-scalar receiving systems for diagnostics of vibration and defectoscopy of building structures. Comparative analysis of the fluctuations of the scalar and energy flux components of the structural noise acoustic field was conducted using computer simulation. Suppression of this noise contributes to a more precise localization of defects in constructions. The study was conducted in view of the fact that the component of the stream of the acoustic field, for which the intensity of the structural noise is minimal, is measured indirectly, using two sensors: scalar and vector. It is shown that the use of energy flux component can increase the detection efficiency.

    Keywords: flaw detection, structural noise, fluctuation, components of the acoustic field, energy flux

  • The algorithms of strategies’ synthesis in three-criterial problem of single-processor servicing in stationary objects grouping

    The maintenance model of group of stationary objects in a one-dimensional working area by moving processor is considered. The processor performs one-step service cycle without interruptions, which begins and ends at the base point. For every object assumed to be given its location, the required length of service, an early start of service and function of the individual fines. We study the problem of multiple criteria, where total traveled processor length, time of return of the processor in the base point after the service of all objects of a given group and the total fine value of all objects act as minimized criteria. The solution is performed using formulas based on the principle of dynamic programming, and also based on the ideology of evolutionary genetic algorithms. When using dynamic programming we study questions of construction of complete sets of effective assessments. The problems of comparing two sets of estimates, the computational complexity, an example and results of the experiments are considered.

    Keywords: multi-objective optimization, maintenance strategy, dynamic programming, evolutionary computation, NP-difficulty, mobile processor, stationary objects

  • Mathematical model of implicit-pole synchronous generator of mini-CHP

    In this paper we propose mathematical model of implicit-pole synchronous generator of mini-CHP. The model is based on a full Park-Gorev differential equation. The saturation of the machine is taken by using the method of partial magnetic characteristics. This method allows most accurate evaluation of the change of parameters of an equivalent circuit of the nonsalient-pole generator in the absence of information about the magnetic properties of the machine. The model is Implemented in Simulink. Application of the model is possible when calculating the steady-state and transients in distribution electrical net wich contains implicit-pole synchronous generators.

    Keywords: nonsalient-pole synchronous generator, implicit-pole generator, mathematical model, Park-Gorev differential equation, magnetic characteristics, transients

  • Simulation of the design activity diversification of innovative enterprise

    Calculate the aerial and / or hydrodynamic effects from the continuous medium required for the synthesis of an adequate control system. Numerical simulation of movement managed position-control trajectory mini-ship at small angles of heel and the presence of sea waves on the basis of a fully-mathematical model and the proposed methodology for assessing the hydrodynamic impact.

    Keywords: surface mini-boat, position-control trajectory, aerohydrodynamics, mathematical model, nonlinear dynamics, CFD modeling, external disturbances