616 research outputs found

    Time-delayed feedback control of coherence resonance near subcritical Hopf bifurcation: theory versus experiment

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    Using the model of a generalized Van der Pol oscillator in the regime of subcritical Hopf bifurcation we investigate the influence of time delay on noise-induced oscillations. It is shown that for appropriate choices of time delay either suppression or enhancement of coherence resonance can de achieved. Analytical calculations are combined with numerical simulations and experiments on an electronic circuit

    Experimental Comparisons of Derivative Free Optimization Algorithms

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    In this paper, the performances of the quasi-Newton BFGS algorithm, the NEWUOA derivative free optimizer, the Covariance Matrix Adaptation Evolution Strategy (CMA-ES), the Differential Evolution (DE) algorithm and Particle Swarm Optimizers (PSO) are compared experimentally on benchmark functions reflecting important challenges encountered in real-world optimization problems. Dependence of the performances in the conditioning of the problem and rotational invariance of the algorithms are in particular investigated.Comment: 8th International Symposium on Experimental Algorithms, Dortmund : Germany (2009

    Features Smelting of Iron and Silicate Materials in the Solid Fuel Low Shaft Furnace

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    Рассмотрен процесс плавки чугуна и силикатных материалов в твердотопливной низкошахтной печи (вагранке) при замене кокса антрацитом и тощими углями. Приведено теоретическое и практическое обоснование основных технологических параметров процесса. Установлен оптимальный уровень загрузки материалов при плавке чугуна и силикатных материалов в твердотопливной низкошахтной печи, способ подачи дутья в кислородную зону печи и температура дутьяThe process of smelting iron and silicate materials in the solid fuel low shaft furnace (cupola) by replacing coke by anthracite and lean coal. The theoretical and practical study of the basic technological parameters of the process. The optimal level of loading of materials in the smelting of iron and silicate materials in the solid-low shaft oven, a method of supplying oxygen into the blast zone of the furnace and the blast temperatur

    The Interaction of Plasma Sialylated and Desialylated Lipoproteins with Collagen from the Intima and Media of Uninvolved and Atherosclerotic Human Aorta

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    We have evaluated the binding of sialylated and desialylated lipoproteins to collagen isolated from the proteoglycan and musculoelastic layers of intima and media of uninvolved human aorta and atherosclerotic lesions. Comparing various collagen preparations from the uninvolved intima-media, the binding of sialylated apoB-containing lipoproteins was best to collagen from the intimal PG-rich layer. Binding of sialylated apoB-containing lipoproteins to collagen from this layer of fatty streak and fibroatheroma was 1.4- and 3.1-fold lower, respectively, in comparison with normal intima. Desialylated VLDL versus sialylated one exhibited a greater binding (1.4- to 3.0-fold) to all the collagen preparations examined. Desialylated IDL and LDL showed a higher binding than sialylated ones when collagen from the intimal layers of fibroatheroma was used. Binding of desialylated HDL to collagen from the intimal PG-rich layer of normal tissue, initial lesion, and fatty streak was 1.2- to 2.0-fold higher compared with sialylated HDL

    Geoantineutrino Spectrum, 3He/4He-ratio Distribution in the Earth's Interior and Slow Nuclear Burning on the Boundary of the Liquid and Solid Phases of the Earth's Core

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    The description problem of geoantineutrino spectrum and reactor antineutrino experimental spectrum in KamLAND, which takes place for antineutrino energy \~2.8 MeV, and also the experimental results of the interaction of uranium dioxide and carbide with iron-nickel and silicaalumina melts at high pressure (5-10 GP?) and temperature (1600-2200C) have motivated us to consider the possible consequences of the assumption made by V.Anisichkin and coauthors that there is an actinid shell on boundary of liquid and solid phases of the Earth's core. We have shown that the activation of a natural nuclear reactor operating as the solitary waves of nuclear burning in 238U- and/or 232Th-medium (in particular, the neutron- fission progressive wave of Feoktistov and/or Teller-Ishikawa-Wood) can be such a physical consequence. The simplified model of the kinetics of accumulation and burnup in U-Pu fuel cycle of Feoktistov is developed. The results of the numerical simulation of neutron-fission wave in two-phase UO2/Fe medium on a surface of the Earth's solid core are presented. The georeactor model of 3He origin and the 3He/4He-ratio distribution in the Earth's interior is offered. It is shown that the 3He/4He ratio distribution can be the natural quantitative criterion of georeactor thermal power. On the basis of O'Nions-Evensen-Hamilton geochemical model of mantle differentiation and the crust growth supplied by actinid shell on the boundary of liquid and solid phases of the Earth's core as a nuclear energy source (georeactor with power of 30 TW), the tentative estimation of geoantineutrino intensity and geoantineutrino spectrum on the Earth surface are given.Comment: 28 pages, 12 figures. Added text, formulas, figures and references. Corrected equations. Changed content of some section

    Investigation of genetic structure in mesomorphic bluegrasses, Poa section Stenopoa dum, by using ISSR markers

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    A morphological and genetic analysis of five mesomorphic bluegrasses populations, Poa section Stenopoa, from a range of geographical locations were performed. We have established that all the populations have different level of the morphological and genetic diversity. A total of 79 DNA bands were obtained from six ISSR primers, including 61 polymorphic bands. Molecular data have shown no clear difference between morphologically homogeneous populations and hybrid populations P. palustris and P. nemoralis. This result may be due to the high genetic diversity of the populations studied

    Chronotope of Engineering and Pedagogical Thinking

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    The article is devoted to engineering and pedagogical thinking as a kind of professional thinking that exists due to specific reasons and necessary and sufficient conditions. The “assembly” of these causes and conditions takes place in a certain time-and-place (chronotope), the conceptual reconstruction of which opens the way to overcoming the traditions of haphazard enumerative descriptions of various properties that have developed in the literature and to reaching the construction of the theory of engineering and pedagogical thinking, which, in turn, will help to reasonably update the content and organization of training engineers-teachers, on whom a lot depends in the near technological future of Russia. A review of the characteristics of engineering-pedagogical and related engineering and pedagogical thinking presented in scientific publications is proposed. It shows the need for greater certainty in understanding the nature, foundations, essence and features of heterogeneous engineering and pedagogical thinking. Heterogeneity requires actualization of the potential not only of pedagogy and technical sciences, but also of philosophy, cultural studies, sociology, and psychology. Such actualization shows the heuristic of the communicative interpretation of the nature and essence of thinking. In its light, engineering-pedagogical thinking appears simultaneously as an articulated and unarticulated, discrete and continuous communication of engineers-teachers with students, within which the competencies required by the profession and the impulse developing engineering and technical flair and ingenuity are transmitted, “infecting” (V. Shklovsky2) and charging them, thanks to which communication overcomes the boundaries of the chronotope, gaining continuum features, demonstrating its pulsating situational-suprasituative (corpuscular-wave) dualism. The scientific novelty lies in the justification, by the example of advancing to the theory of engineering and pedagogical thinking, of supplementing the competence approach with consideration of no less significant cultural and subcultural factors, including latent ones, which sometimes manifest themselves in very weak signals about the features of the chronotope of training engineers and technicians by engineers–teachers, not so much by virtue of official regulations as by virtue of singular acts of everyday life communication
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