181 research outputs found

    On approximations by trigonometric polynomials of classes of functions defined by moduli of smoothness

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    In this paper, we give a characterization of Nikol'ski\u{\i}-Besov type classes of functions, given by integral representations of moduli of smoothness, in terms of series over the moduli of smoothness. Also, necessary and sufficient conditions in terms of monotone or lacunary Fourier coefficients for a function to belong to a such a class are given. In order to prove our results, we make use of certain recent reverse Copson- and Leindler-type inequalities.Comment: 18 pages. arXiv admin note: substantial text overlap with arXiv:1208.612

    An extreme case of epitoky in an australian collembolon : Isotopenola perterrens sp.n. (Hexapoda : Collembola : Isotomidae)

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    Isotopenola perterrens sp.n. is described from a 40 year old Eucalyptus plantation in Victoria, Australia, and its occurrence in an adjacent site of remnant native vegetation is reported. Fully adult males are armed with numerous strong spine-like macrochaetae on lateral parts of head and body tergites and with fields of long bristles on latero-ventral and ventral areas of abdomen. Antennae of epitokous males are of normal shape but bear thickened chaetae. This is the second and most extreme case of epitoky recorded in the genus. The occurrence of sexual dimorphism, of which epitoky is a subset, is summarised for Australian Collembola. Environmental factors that appear to facilitate successful recolonisation of native fauna onto revegetated sites in Australia are proposed. © Senckenberg Gesellschaft für Naturforschung

    New species of Entomobryini from Russia and Armenia (Collembola, Entomobryomorpha)

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    This paper is part of the results of a systematic study of the specimens of Entomobrya and related genera from various European museums and other material obtained from private collections. Various new species from Russia and Armenia were identified: Entomobrya karasukensis n. sp., Entomobrya tuvinica n. sp., Entomobrya pseudolanuginosa n. sp., Entomobrya stebaevae n. sp., Entomobrya kuznetsovae n. sp., Entomobrya brinevi n. sp., Entomobrya primorica n. sp., Entomobrya kabardinica n. sp., Entomobrya taigicola n. sp., Entomobryoides sotoadamesi n. sp. and Prodrepanura altaica n. sp. from Russia, and Entomobrya armeniensis n. sp. from Armenia. For the identification and description of these species we used the set of characters proposed by Jordana and Baquero (2005)

    Redescription of Folsomia loftyensis Womersley with notes on the sensillary arrangement of the genital segment in the genus (Collembola : Isotomidae)

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    Folsomia loftyensis Womersley is redescribed based on material from South Australia, Victoria and Queensland. The species exhibits, for the genus, an unusual sensillary pattern on the posterior abdominal segments. The arrangement and form of the five sensilla on the genital segment of most described species of Folsomia from the Palearctic are analysed and species divided into groups based on these characters. Several different lineages are detected. © 2010 Elsevier GmbH. All rights reserved

    Opening of Nitride Spent Nuclear Fuel

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    Nitride nuclear fuel (UN + 10-20% PuN) is considered a promising alternative to the widely used oxide nuclear fuel (UO2). Thermal conductivity and density of nitride fuel are ∼ 7 times and 1.3 times higher than that of oxide fuel, respectively. Nitride fuel demonstrates a good compatibility with the cladding of fuel rods made of stainless steel. Along with the development of new fuel, methods for its subsequent processing are being developed. Various options for the initial opening of nitride spent nuclear fuel (SNF) are considered in this article. The use of gaseous chlorine is technologically inconvenient and dangerous when working with radioactive substances. The electrochemical dissolution of nitride SNF cannot be realized due to the formation of a by-product - UNCl. Uranium nitride chloride is an insulator and it blocks the electrochemical process. It was found that the chlorination of nitride SNF with cadmium or lead chlorides makes it possible to carry out 100% UN → UCl3 conversion. The use of voloxidation (oxidation of nitride SNF to oxides) as the first stage of processing will make the entire technology universal, suitable for processing both nitride and oxide SNF. The choice of the method for opening SNF depends on the choice of the subsequent stages of its processing. Keywords: nitride spent nuclear fuel, SNF, chlorination, anodic dissolution, UNCl, “soft” chlorination, voloxidation, processin

    A STABLE METHOD FOR LINEAR EQUATION IN BANACH SPACES WITH SMOOTH NORMS

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    A stable method for numerical solution of a linear operator equation in reflexive Banach spaces is proposed. The operator and the right-hand side of the equation are assumed to be known approximately. The corresponding error levels may remain unknown. Approximate operators and their conjugate ones must possess the property of strong pointwise convergence. The exact normal solution is assumed to be sourcewise representable and some upper estimate for the norm of its source element must be known. The norm in the Banach space of solutions is supposed to satisfy the following smoothness-type condition: some function of the norm must be differentiable. Under these conditions a stability of the method with respect to nonuniform perturbations in operator is shown and the strong convergence to the normal solution is proved. A boundary control problem for the one-dimensional wave equation is considered as an example of possible application. The results of the model numerical experiments are presented

    Analysis of vibroprotection characteristics of pneumatic relaxation seat suspension with capability of vibration energy recuperation

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    This paper proposes mechanism and control algorithm for pneumatic relaxation system of suspension with vibration energy recuperation applied to standard vehicle operator seat (“Sibeko” company). Mathematical model of the seat pneumatic relaxation suspension with two additional air volumes was created. Pneumatic motor – recuperator activated by means of air flow from the one additional volume to another is installed in air piping between additional volumes. Computational research was made in Matlab/Simulink. Amplitude-frequency characteristics of transmission coefficient for standard and proposed suspensions were plotted for preliminary evaluation of vibration protection properties of seat suspension. Performed comparative analysis of amplitude-frequency characteristics shows that noticeable improvement of vibration protection properties of pneumatic relaxation suspension system with vibration energy recuperation in comparison with standard system both in region of resonance disturbances and in above-resonance region. Main ways for further improvement of vibration protection properties of proposed system were marked out
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