721 research outputs found

    Lifetime assessment for an ideal elastoplastic thick-walled spherical member under general mechanochemical corrosion conditions

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    The problem of the equal-rate mechanochemical wear of an elastic-perfectly plastic thick-walled spherical shell under internal and external pressure is solved analytically. The proposed solution allows to assess the time of the initial yielding at the bore of the shell and the time of fully plastic yielding. The obtained formulas are to be used for design purposes and as a benchmark solution for numerical analysis

    Asymmetric Coupling in Two-Channel Simple Exclusion Processes

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    Simple exclusion processes for particles moving along two parallel lattices and jumping between them are theoretically investigated for asymmetric rates of transition between the channels. An approximate theoretical approach, that describes the particle dynamics exactly in any vertical cluster of two parallel sites and neglects the correlations between the different vertical clusters, is applied to calculate stationary-state density profiles, currents and phase diagrams. Surprisingly, it is found that asymmetry in the coupling between the channels leads to a very complex phase behavior that is very different from two-channel simple exclusion processes with symmetric coupling. There are seven stationary-state phases in the simple exclusion processes with asymmetric transition rates between the channels, in contrast to three phases found for the systems with symmetric coupling. In addition, a new maximal-current phase with a domain wall in the middle of the lattices, that has no analogs in other exclusion processes, is observed. Although the explicit calculations are presented only for the case of full asymmetry, when the particles can only jump between the channels in one direction, the properties of two-channel simple exclusion systems with general asymmetry are also discussed. Theoretical predictions are in excellent agreement with extensive computer Monte Carlo simulations.Comment: 12 pages, 6 figure

    Inhomogeneous Coupling in Two-Channel Asymmetric Simple Exclusion Processes

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    Asymmetric exclusion processes for particles moving on parallel channels with inhomogeneous coupling are investigated theoretically. Particles interact with hard-core exclusion and move in the same direction on both lattices, while transitions between the channels is allowed at one specific location in the bulk of the system. An approximate theoretical approach that describes the dynamics in the vertical link and horizontal lattice segments exactly but neglects the correlation between the horizontal and vertical transport is developed. It allows us to calculate stationary phase diagrams, particle currents and densities for symmetric and asymmetric transitions between the channels. It is shown that in the case of the symmetric coupling there are three stationary phases, similarly to the case of single-channel totally asymmetric exclusion processes with local inhomogeneity. However, the asymmetric coupling between the lattices lead to a very complex phase diagram with ten stationary-state regimes. Extensive Monte Carlo computer simulations generally support theoretical predictions, although simulated stationary-state properties slightly deviate from calculated in the mean-field approximation, suggesting the importance of correlations in the system. Dynamic properties and phase diagrams are discussed by analyzing constraints on the particle currents across the channels

    Parallel Coupling of Symmetric and Asymmetric Exclusion Processes

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    A system consisting of two parallel coupled channels where particles in one of them follow the rules of totally asymmetric exclusion processes (TASEP) and in another one move as in symmetric simple exclusion processes (SSEP) is investigated theoretically. Particles interact with each other via hard-core exclusion potential, and in the asymmetric channel they can only hop in one direction, while on the symmetric lattice particles jump in both directions with equal probabilities. Inter-channel transitions are also allowed at every site of both lattices. Stationary state properties of the system are solved exactly in the limit of strong couplings between the channels. It is shown that strong symmetric couplings between totally asymmetric and symmetric channels lead to an effective partially asymmetric simple exclusion process (PASEP) and properties of both channels become almost identical. However, strong asymmetric couplings between symmetric and asymmetric channels yield an effective TASEP with nonzero particle flux in the asymmetric channel and zero flux on the symmetric lattice. For intermediate strength of couplings between the lattices a vertical cluster mean-field method is developed. This approximate approach treats exactly particle dynamics during the vertical transitions between the channels and it neglects the correlations along the channels. Our calculations show that in all cases there are three stationary phases defined by particle dynamics at entrances, at exits or in the bulk of the system, while phase boundaries depend on the strength and symmetry of couplings between the channels. Extensive Monte Carlo computer simulations strongly support our theoretical predictions.Comment: 16 page

    DEVELOPMENT OF A SYSTEM FOR ASSESSING PASSENGER TRAFFIC BASED ON FUZZY LOGIC

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    A methodology has been developed for assessing public transport passenger traffic in the city. A mathematical model based on fuzzy logic is presented. The main criteria for assessing the attractiveness of passenger traffic are: the interval between vehicles, technical condition of the vehicle, route length, time of day. In the mathematical model, all input linguistic variables and output variable, their terms and membership functions are described. A fragment of a fuzzy knowledge base presented in the form of production rules is presented. At the exit, the dispatcher receives an output variable – the degree of confidence in the attractiveness of the route. Based on this assessment, the dispatcher can make a number of necessary changes to improve the functioning of the route. The software is implemented as a web service. This software will be convenient for dispatchers to use for planning public transport routes. Fifteen selected routes were taken for research, which are the most popular in the city. These routes were proposed for evaluation by three controllers. The results obtained from dispatchers were compared with the results of the fuzzy inference implemented in the software. The main advantage of using this software product is the ability to build a dynamic schedule based on the analysis of the dispatcher. This, in turn, will allow passengers to receive a better transportation service within the cit

    Spontaneous Symmetry Breaking in Two-Channel Asymmetric Exclusion Processes with Narrow Entrances

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    Multi-particle non-equilibrium dynamics in two-channel asymmetric exclusion processes with narrow entrances is investigated theoretically. Particles move on two parallel lattices in opposite directions without changing them, while the channels are coupled only at the boundaries. A particle cannot enter the corresponding lane if the exit site of the other lane is occupied. Stationary phase diagrams, particle currents and densities are calculated in a mean-field approximation. It is shown that there are four stationary phases in the system, with two of them exhibiting spontaneous symmetry breaking phenomena. Extensive Monte Carlo computer simulations confirm qualitatively our predictions, although the phase boundaries and stationary properties deviate from the mean-field results. Computer simulations indicate that several dynamic and phase properties of the system have a strong size dependency, and one of the stationary phases predicted by the mean-field theory disappears in the thermodynamic limit.Comment: 13 page

    ПРОБЛЕМИ ІДЕНТИЧНОСТІ Й ТРАДИЦІЇ У МОНУМЕНТАЛЬНОМУ ЖИВОПИСІ КИРИЛІВСЬКОЇ ЦЕРКВИ XII ТА XIX СТ. НА ПРИКЛАДІ АНГЕЛЬСЬКИХ ЧИНІВ. (Identity and Tradition Issues in Monumental Painting of XII and XIX Centuries of St. Cyril's Church by an Example of Angelic Ranks.)

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    Статтю присвячено осмисленню проблеми ідентичності та традиції у стінописі XII та ХІХст. Кирилівської церкви на прикладі зображення чинів небесної ієрархії. Аналізуються особливості, спільні та відмінні риси зображень ангельських чинів Кирилівської церкви XII та XIX cm. (The article is devoted to understanding the identity and tradition issues in murals ofXII and XIX centuries of St. Cyril's Church by an Example of celestial hierarchy ranks images. The author analyzes the characteristics, differences and similarities of angelic ranks images of St. Cyril's Church in the XII and XIX centuries.

    Алгоритмы расчёта параметров электрохимического биосенсора

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    The aim of this work is to present the experimental results in the form of an algorithm for analyzing the modification of screen printed electrodes, including the possibility of its regeneration for irreversibly oxidizing biologically active compounds (drugs, DNA and proteins). A protocol was developed for quantitative analysis and study of the mechanism of drug-DNA interaction by differential pulse voltammetry, including the following parameters: complex binding constant, Gibbs free energy, and electrochemical coefficients of the toxic effect.Цель работы – представить экспериментальные результаты в виде алгоритма анализа модификации печатного графитового электрода, включая возможность его регенерации для необратимо окисляющихся биологически активных соединений. Разработан протокол количественного анализа и исследования механизма взаимодействия лекарственный препарат-ДНК методом дифференциально- импульсной вольтамперометрии, включающий следующие параметры: константу связывания комплекса, свободную энергия Гиббса и электрохимический коэффициент токсичности препарата
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