4,472 research outputs found

    On a construction of self-dual gauge fields in seven dimensions

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    We consider gauge fields associated with a semisimple Malcev algebra. We construct a gauge-invariant Lagrangian and found a solution of modified Yang-Mills equations in seven dimensions.Comment: 10 pages, LaTeX, no figure

    Incoherent pion photoproduction on the deuteron in the first resonance region

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    Incoherent pion photoproduction on the deuteron is studied in the first resonance region. The unpolarized cross section, the beam asymmetry, and the vector and tensor target asymmetries are calculated in the framework of a diagrammatic approach. Pole diagrams and one-loop diagrams with NNNN scattering in the final state are taken into account. An elementary operator for pion photoproduction on the nucleon is taken in various on-shell forms and calculated using the SAID and MAID multipole analyses. Model dependence of the obtained results is discussed in some detail. A comparison with predictions of other works is given. Although a reasonable description of many available experimental data on the unpolarized total and differential cross sections and photon asymmetry has been achieved, in some cases a significant disagreement between the theory and experiment has been found. Invoking known information on the reactions γdπ0d\gamma d\to\pi^0 d and γdnp\gamma d\to np we predict the total photoabsorption cross section for deuterium. We find that our values strongly overestimate experimental data in the vicinity of the Δ\Delta peak.Comment: 22 pages, 23 figure

    Methodological Toolkit for Assessing the Investment Attractiveness of Renewable Resources in Northern and Arctic Territories

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    This article examines a pressing issue of assessing the investment attractiveness of renewable resources in underdeveloped Northern and Arctic territories that have a huge untapped natural resource potential. The subject of the study is the economic interactions that occur during the development of natural resource potential. The goal of this study is to develop the methodological toolkit for assessing the investment attractiveness for businesses and government authorities at various levels. At the pre-investment stage of development projects, we identified typical landscapes for zoning of the territory and assessed them for each type of renewable natural resources. Based on an analysis of existing approaches to natural resource zoning, the authors propose to identify three types of landscapes, including those that are attractive in terms of investment, those that are attractive in terms of investment with certain limitations, and those that are unattractive for investment. The study has confirmed the hypothesis that the selection of the most valuable natural resources expands the opportunities for their economic use. The investment attractiveness is determined by favorable geographical location, development of regional infrastructure, natural potential viewed as a priority object. The authors have provided the rationale for the need to valuate the natural resource potential of landscape areas within the boundaries of an assessed territory for the purposes of their ranking based on establishing the investment attractiveness. The limitations may be imposed by the low level of infrastructure development prerequisites, insufficient sustainability of landscapes to anthropogenic influences, export of raw materials for processing outside the territory, etc. The authors have substantiated the list of conditions that require the introduction of correction coefficients to the value indicators of natural resource potential in landscape areas. The main findings of the study are presented in the form of landscape zoning of the territory and methodological toolkit for assessing the investment attractiveness tested in Berezovsky Municipal District of Khanty-Mansi Autonomous Okrug—Yugra.The article has been prepared under the Grant No. 14–18–00456 "Substantiating the Geo-Eco-Socio-Economic Approach to the Development of Strategic Natural Resource Potential of Northern Understudied Territories as Part of The Arctic—Central Asia Investment Project " provided by the Russian Science Foundation

    Evolution of surface defects in platinum alloy wire under drawing

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    The shape and chemical composition of particles polluting the surface of ultrafine wire made of the platinum Pt92.5Pd4Rh3.5 alloy has been revealed by electron microscopy and microspectral analysis. The phenomenon of the appearance of pores in the particles, which are elongated in the direction of drawing, has been discovered. The problem of calculating the stress-strain state is stated by the finite element method. After solving the problem, it is demonstrated that the appearance of additional defects is related to the proportion of stresses in the scheme of metal forming by drawing. © 2017 Author(s).The work was done within the State Task, theme No. 01201375904, and financially supported by the RF Government, No. 211 (contract No. 02.A03.21.0006)

    The properties of coke breeze briquettes produced by ram briquetting

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    The paper reports on the results of briquetting coke breeze with a binder in a closed cylindrical press-die. Liquid glass is used as a binder. Approximating curves for the "compaction ratio vs. compaction pressure" dependences are plotted from experimental data. The mechanical properties of the briquettes are determined, namely, drop damage resistance and breaking stress. The results are presented as approximating dependences in the form of a power function. © 2017 Author(s)

    Orbital stability of solutions to the problem on capillary-gravity waves in two-fluid layer

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    Going back to N. E. Kochin [1] problem about capillary-gravity waves on interface of two-fluid flow is considered as bifurcation problem with spectral parameters
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