1,239 research outputs found

    Modeling of "groove" rolling defect on internal surface of pipes at lengthwise rolling

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    The research has been conducted in pipe forming at rolling off by lengthwise rolling mill with stub mandrel; the patterns of change in dimensionless parameters were determined, which characterize deformation in side angle depending on http://www.multitran.ru/c/m.exe?t=424995_2_1elongation ratio. The model of formation of lengthwise groove on internal surface of pipes has been proposed

    Seismological Implication to the Tectonic Evolution of the Lützow-Holm Bay Region (East Antarctica)

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    Passive source studies using teleseismic events demonstrated heterogeneous structure in the Lützow-Holm Bay (LHB) region, East Antarctica. Depth variations of upper mantle discontinuities (410 and 660 km) were derived from long-period receiver functions by local array stations. Shallow depths in topography of upper mantle discontinuity were cleared beneath the continental ice sheet back azimuth. These results reflect a paleo-upwelling of the mantle plume associated with Gondwana breakup. Lithospheric mantle anisotropy derived by shear waves’ (SKS) splitting anticipated a relationship between “fossil” anisotropy and the past tectonics in NE-SW orientation. Origin of mantle anisotropy was assumed to be caused by supercontinent assembly rather than present asthenospheric flow parallel with absolute plate motion. The deep seismic surveys by active sources, moreover, were carried out over continental ice sheet and provided clear information on crust-mantle boundary, together with inner lithospheric mantle reflections. The extracted lithospheric cross-sectional images by seismic reflection analyses implied tectonic influence of compressive stress during Pan-African age

    Measuring spin in coalescing binaries of neutron stars showing double precursors

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    Gamma-ray bursts resulting from binary neutron-star mergers are sometimes preceded by precursor flares. These harbingers may be ignited by quasi-normal modes, excited by orbital resonances, shattering the stellar crust of one of the inspiralling stars up to 10\gtrsim10 seconds before coalescence. In the rare case that a system displays two precursors, successive overtones of either interface- or gg-modes may be responsible for the overstrainings. Since the free-mode frequencies of these overtones have an almost constant ratio, and the inertial-frame frequencies for rotating stars are shifted relative to static ones, the spin frequency of the flaring component can be constrained as a function of the equation of state, the binary mass ratio, the mode quantum numbers, and the spin-orbit misalignment angle. As a demonstration of the method, we find that the precursors of GRB090510 hint at a spin frequency range of 2ν/Hz202 \lesssim \nu_{\star}/\text{Hz} \lesssim 20 for the shattering star if we allow for an arbitrary misalignment angle, assuming =2\ell=2 gg-modes account for the events.Comment: 11 pages, 6 figures, 2 tables, with an appendix containing 1 figur

    General-relativistic treatment of tidal gg-mode resonances in coalescing binaries of neutron stars. II. As triggers for precursor flares of short gamma-ray bursts

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    In some short gamma-ray bursts, precursor flares occurring \sim seconds prior to the main episode have been observed. These flares may then be associated with the last few cycles of the inspiral when the orbital frequency is a few hundred Hz. During these final cycles, tidal forces can resonantly excite quasi-normal modes in the inspiralling stars, leading to a rapid increase in their amplitude. It has been shown that these modes can exert sufficiently strong strains onto the neutron star crust to instigate yieldings. Due to the typical frequencies of gg-modes being 100 Hz\sim 100\text{ Hz}, their resonances with the orbital frequency match the precursor timings and warrant further investigation. Adopting realistic equations of state and solving the general-relativistic pulsation equations, we study gg-mode resonances in coalescing quasi-circular binaries, where we consider various stellar rotation rates, degrees of stratification, and magnetic field structures. We show that for some combination of stellar parameters, the resonantly excited g1g_1- and g2g_2-modes may lead to crustal failure and trigger precursor flares.Comment: 14 pages, 8 figures, 2 tables, submitted to MNRA

    Beam test results of 3D fine-grained scintillator detector prototype for a T2K ND280 neutrino active target

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    An upgrade of the long baseline neutrino experiment T2K near detector ND280 is currently being developed with the goal to reduce systematic uncertainties in the prediction of number of events at the far detector Super-Kamiokande. The upgrade program includes the design and construction of a new highly granular fully active scintillator detector with 3D WLS fiber readout as a neutrino target. The detector of about 200×180×60 cm3200\times 180\times 60~cm^3 in size and a mass of \sim2.2~tons will be assembled from about 2×1062\times10^6 plastic scintillator cubes of 1×1×1 cm31\times1\times1~cm^3. Each cube is read out by three orthogonal Kuraray Y11 Wave Length Shifting (WLS) fibers threaded through the detector. A detector prototype made of 125 cubes was assembled and tested in a charged particle test beam at CERN in the fall of 2017. This paper presents the results obtained on the light yield and timing as well as on the optical cross-talk between the cubes.Comment: 5 pages, 8 figure

    The role of customer service in increasing the competitive ability and competitiveness of service organizations

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    The essence of service and service as a product of the service business, including the core of the service, its customized variants, atmosphere, architecture and contact personnel, has been characterized. It has been found out that customer orientation is a key characteristic of a business in the service sector and reflects a combination of understanding of its strategic vectors, its essential characteristics and the vision of the organization through the eyes of the client (internal - employee and external - consumer). It has been determined that a customer-oriented service consists in focusing attention on the customer, rather than on a product-centered marketing strategy. The components of a successful customer-oriented service have been highlighted, based on the quality of services provided, the level of accompanying service, the range of services provided and the availability of after-sales service. It has been noted that nowadays there is a shift in the relationship between sellers and buyers from onetime transactions to long-term partnership relations

    COMPARATIVE ANALYSIS OF THE CONCEPTS OF «COMPETITIVE STABILITY» AND «COMPETITIVENESS» OF SERVICE ORGANIZATIONS

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    A comparative analysis of the categories, that form the concepts of competitiveness and competitive stability in relation to the organization of the services sector, has been conducted. The main approaches to the definition of categories and concepts, such as «competitive position», «competitive status», «competitive potential», «competitive advantages» have been analyzed. Their clarifications regarding the organizations of the service sector have been made. Based on the conducted comparative analysis, the concept of competitive advantages has been formulated as a basis for the formation of competitiveness and potential competitive stability of the organization of the services sector

    Dynamics of the Free Surface of a Conducting Liquid in a Near-Critical Electric Field

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    Near-critical behavior of the free surface of an ideally conducting liquid in an external electric field is considered. Based on an analysis of three-wave processes using the method of integral estimations, sufficient criteria for hard instability of a planar surface are formulated. It is shown that the higher-order nonlinearities do not saturate the instability, for which reason the growth of disturbances has an explosive character.Comment: 19 page
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