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  • Brain activity modeling based on the model of Hodgkin-Huxley

    Brain neural networks models based on the model of Hodgkin-Huxley and the inhibitory and excitatory postsynaptic potentials EPSP and IPSP balance problem are investigated. The problem of the inhibitory and excitatory postsynaptic potential balance, affecting such person's ability as learning, memory, movement, ability to analyze and so on has great scientific and practical importance. Implementation of the model Hodgkin-Huxley in the Matlab environment is made. Model modification is considered given the occurrence of a synapse in neuron system.

    Keywords: mathematical modeling, EPSP, IPSP, ionic channel, modified model parameter, neural network model, Hodgkin-Huxley

  • Management properties of PZT piezo-ceramic material used in sonar radiating elements

    Piezoceramics phases of (1-х)PbTiO3-xPbZrO3 is the basis of most high-performance piezoelectric materials. Electrophysical and mechanical properties of these materials can be varied over a wide range by varying the composition and by processing methods: the methods and modes of sintering conditions polarization. Topical to study the influence on the properties of PZT materials processing methods at the stages of manufacturing piezoelectric samples. In the role model of the object has been selected multicomponent system PbTiO3-PbZrO3-PbNb2/3Zn1/3O3-PbW1/2Mg1/2O3-PbSb2/3Mn1/3O3. Samples of piezoelectric elements for the study were obtained in two ways: in the first case, the sintering samples was carried out by the usual ceramic technology, and in the second by hot pressing. The grain structure was formed in both cases in the presence of the glass phase, the quantity of which decreases with increasing temperature, while in the first case, an increase in the velocity of the secondary recrystallization, and in the second of its suppression. It was found that regardless of the technology of the samples εT33/ε0, d33 and VЕ1 at high temperatures, due to the increase of grain and coercive field, which complicates the process of polarization. Maximum values εT33/ε0, d33 and VЕ1 samples prepared by hot pressing at 10 - 15% higher than if received by conventional ceramic technology.

    Keywords: Piezoelectric ceramics, doping, combination, pezophase, piezomaterial

  • High-strength concretes with high volume fly ash of Kansk-Achinsk brown coal basin

    Strength properties of high-strength concrete on the basis of a mixture of high-calcium ash and cement crushed to a specific surface of 600 m2 / kg in the presence of a superplasticizer were investigated. It was established that at the initial stages of hardening of the binder, its strength strongly depends on the dosage of fly ash and it depends little on the water/binder ratio. After 28 days of hardening, the strength of concrete, depends more on the water-binder ratio, rather than on the ash content of the cement-ash binder. There was concluded that minerals of fly ash affect on strength of the cement-ash binder in later periods, and at the initial stages, its hardening is provided by hydration of the cement clinker. It was established that in high-strength concretes was no decrease in strength in later periods when using finely grinding ash containing a significant amount of free CaO.

    Keywords: high-strength concrete, fly ash, free CaO, cement-ash binder, strength, dump strength

  • Theoretical work basis and design philosophy of highcurrent coaxial type termoresistors

    Thermoresistors nowadays are used not only as parts of temperature sensors and flowmeters but they are used as components of starting and control devices. Use of low-powered thermoresistors as starting and control devices parts needs a lot of devices that reduces equipment reliability. Current step-up running through motor-starting devices simplifies control circuit. For using thermoresistors in electric circuits with high-discharge rate it is necessary to use special constructions in order not to let termoresistor body be overheated. Thermoresistor expansion results in changing of thermal fields distribution pattern inside this semiconductor. The authors show calculated characteristics which let determine proportions and shapes of semiconductor subject to thermoresistor temperature.

    Keywords: high power thermoresistors, thermoresistors of coaxial type, current density, temperature, analogy criterion, thermal conductance, temperature gradient, thermal field, stability criterion

  • The method of forming a reduced order modelof microelectromechanical systems using the ANSYS software suite integrated means

    The article describes the role of reduced order models (ROM) in MEMS design & testing, reflects their advantages in comparison with the finite element method (FEM) full models for real-time behavioral modeling of MEMS dynamic characteristics and versatile research of the objects' properties. The mathematical interpretation of the procedure for reducing the system dynamics equations order by switching from the full model presented in the form of state variables equations to the ROM state variables equations is given, the four existing scientific methods for reducing the FEM model order are presented in generalized form. The particularities of embedded ANSYS software capabilities application to automatically generate the ROM from the original full FEM model with lower computer power requirements and the preservation of the original model accuracy in the presence of only the structural mechanics are set out in details. Two equal algorithms for further work with the ROM in MatLab software in order to simulate the MEMS dynamics and study time and frequency properties of the model are presented: by designing the scheme consisting of prearranged Simulink function blocks and by writing an M-file program listing using the special MatLab programming language. Scientific novelty of the results is the combination of the methods for MEMS design (system of partial differential equations, ANSYS program) and behavioral modeling (system of ordinary differential equations, MatLab program) that can significantly reduce the complexity of the FEM model adaptation to the real-time modeling and eliminate computation errors.

    Keywords: micro-electro-mechanical system, finite element method, behavioral modeling, reduced order model, ANSYS, MatLab

  • A method of the identified signals relationships combining using cluster analysis

    The method of the identified signals relationships combining is proposed. Those relationships are represented in the form of precedents of the distributed control system. The method is based on the cluster analysis for further identification of the most interrelated precedents with the aim of source localization of emergency

    Keywords: precedent, cluster, decision tree, gradient, data mining, reliability, method

  • Design solutions for strengthening of soil foundation of a residential building

    The article presents the project design to strengthen the foundation reinforcement to soils through the gaps arranged at the discharge cementogenesis solutions. Also describes development work at the construction site, which allowed to adjust the project and reduce the cost of consolidation.

    Keywords: Reinforcement, soil, comentaron, cementation, directional hydraulic fracturing, drilling, well, development work

  • A comparison of the antiwear properties of water-organic solutions containing nano-sized particles of lead and palladium

    A promising direction of creation of new lubricants is their modification by nanoclusters of metals, which form in the zone of friction of the protective film, providing reduction of wear of friction pairs. In this regard, the aim of this work is to study tribological properties of lubricating compositions containing nanosized particles of lead and palladium. A lubricating composition was obtained in aqueous solution during electrolysis with a lead anode or in the presence of salts of palladium in an ultrasonic field (complex processing). Tribological studies showed that the lubricating compositions have high anti-wear and extreme pressure properties.

    Keywords: nanoscale particles, friction, wear, anti-wear and antiwelding properties

  • Recommendations on the selection of bearing parts in order to increase the service life of a bridge structure

    One of the most important elements of the bridge, from which the service life of this structure directly depends, is the supporting part. It provides the movement and rotation of span structures, as well as the transfer of all loads from the forces acting on them to the supports. The task of the designer is to select such support parts, that could be allowed maximum reducing of the forces, acting at the ends of the beams and having a minimum resistance to their free movement. It is necessary in each case to select the support part, which will most closely meet the requirements. To solve this problem, the author structured and tabulated the kinds of support parts. And also an analysis of the main characteristics of some of them.

    Keywords: bearing part, exothermia, bridge structure, durability, service life, transfer of loads and displacements, deforming systems, sliding systems, rolling systems

  • "Using a network statistical models in the practice of political analysis "

    This article discusses some of the problems arising in the study of political processes of network modeling methods. The relation of concepts, models and their practical application in the analysis of political events is analyzed. The purpose of work is to examine the hypothesis testing problem in the practice of political analysis using empirical methods in the field of cooperation between public institutions and networks of civic engagement structures. It is shown that the use of network modeling methods to move from descriptive methods, cluster analysis to statistical models, reproducing the interaction of political subjects, which makes it possible to produce test of hypotheses by empirical methods. Statistical models combine the methods of qualitative analysis and quantitative methods of hypotheses verification and application of the results of various concepts in political practice. Revealed the limitations of the use of the research capacity of the network models, associated with incomplete empirical data obtained during the field research that requires the experiments, various forms of observation and interviews. Results of the analysis and forecasting can be used in the practice of "network management", aimed at the impact on the network structure by changing the institutional rules and regulations.

    Keywords: network statistical models, network management, policy diffusion, diffusion of innovations

  • Hybrid epoxy-amine hydroxyurethane-grafted polymer

    Cured linear hybrid epoxy-amine hydroxyurethane-grafted polymer are preparedby novel structure with lengthy epoxy-amine chains, pendulous hydroxyurethane units and a controlled number of cross-links. These hybrid polymers combine increased flexibility with well balanced physical-mechanical and physical-chemical properties of conventional epoxy-amine systems and may be used, for example, for manufacturing of synthetic/artificial leather and sport monolithic floorings. US Patent Application 14/296,478, filed June 05, 2014.

    Keywords: linear epoxy-amine chains, hybrid hydroxyurethane-grafted polymers, synthetic nonisocyanate leather.

  • Development of a parametrical model of the ion current signal for driving engines of moving objects

    The article presents the results of approximating of ion current signal of the most appropriate parametrical models in Matlab software. It is shown that in spite of the high accuracy of approximation, parametrical model Gaussian, which chosen early in Matlab, have significant drawbacks. In order to eliminate the identified deficiencies authors was developed parametric model in which the discrete Fourier transform was used to approximate of the ion current signal.

    Keywords: ion current, the internal combustion engine, a parametric model, a discrete Fourier transform, the Gaussian model, the approximation of a signal

  • The main aspects of forming of a human capital in the conditions of formation of economy of knowledge

    The main approaches to forming of a human capital as major factor of economic growth and production resource of economy of knowledge are considered. The main stages of forming of a human capital and the main factors influencing this process are determined

    Keywords: knowledge economy, human capital, competence, intellectual potential, labour potential

  • Additive technology is a dynamically developing production

    This article is dedicated to overview of additive technologies, Russia's place in the modern world of developing technology, a comparative analysis of existing technologies, made predictions about trends in the development of additive technology in our country

    Keywords: additive technology, classification, 3-D-printing, machines, powders for additive technologies, selective laser sintering

  • Analysis methods of the Russian financial market volatility for a wide class of models

    The article considers a problem of the Russian financial market modeling and suggests wide classes of diffusion and jump models. The authors examine the adequacy of the diffusion models by means of quadratic variation analysis on the Russian financial market, which is used to construct the volatility index, the most important quantitative risk indicator in the financial market. It is shown that the existing volatility indexes RTSVX and RVI worse approximate the realized variation than the alternative index, based on the implied variation integration. Further analysis of power variation of log-returns for RTS index shows that Levy processes with unbounded variation without diffusion component better describe the dynamics of the Russian financial market. A new model-free formula for the volatility index is proposed in the class of Lévy processes. The new formula suggested is based on the variation representation via market option prices.

    Keywords: mathematical modeling, numerical method, mathematical finance, volatility index, option, Levy process, diffusion model, quadratic variation, RTS index, derivatives market.