830 research outputs found

    Investigation of changes in conductivity of juice during the evaporation process

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    The creation of this article was the necessity of experimental determination of the electric conductivity of juice depending on the concentration of solids, expressed by the empirical formula, in order to more precisely control specific power supplied to the machine and foaming. Authors of the article held staged experimental studies using apple juice, the juice of red mountain ash, buckthorn and black currant. Found that the relationship between the conductivity of the juice solids content corresponds to the empirical formula of Kohlrausch, however, this formula does not represent the contribution juice acidity value of conductivity, and allows to correlate the specific power input to the device with the concentration of solids. The empirical formulas for the distribution of electrical juice conductivity depending on the acidity and for calculation of the specific power depending on the concentration of dry matter, allows to keep the speed of the foam below its destruction speed in the zone of vigorous reflux

    Effect of Direct Laser Deposition on Microstructure and Mechanical Properties of 316L Stainless Steel

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    Direct laser deposition (DLD) is a modern prototyping manufacturing technology, which can directly build full-density and high-performance complex metal parts This paper presents an investigation of the influence different scanning strategy on microstructure and mechanical properties of DLD 316L stainless steel sample. The results showed that formation of fine equiaxed austenitic structure with average grain size of the dendritic cells in 1.2-1.7 μm. Inter-track idle time has directly influence on cooling rate, grain size and mechanical properties. It was shown that the decreasing of inter-track idle time from 4.37 to 0.75 s decreases the ultimate tensile strength from 729 to 686 MPa. For obtaining high mechanical properties of samples or recovering surfaces it is necessary to choose scanning strategy along the largest dimension of the detail.     Keywords: X-ray analysis; Electron microscopy; Stress/Strain measurements; Iron alloys; Laser/Powder methods

    Non-Abelian Vortices, Super-Yang-Mills Theory and Spin(7)-Instantons

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    We consider a complex vector bundle E endowed with a connection A over the eight-dimensional manifold R^2 x G/H, where G/H = SU(3)/U(1)xU(1) is a homogeneous space provided with a never integrable almost complex structure and a family of SU(3)-structures. We establish an equivalence between G-invariant solutions A of the Spin(7)-instanton equations on R^2 x G/H and general solutions of non-Abelian coupled vortex equations on R^2. These vortices are BPS solitons in a d=4 gauge theory obtained from N=1 supersymmetric Yang-Mills theory in ten dimensions compactified on the coset space G/H with an SU(3)-structure. The novelty of the obtained vortex equations lies in the fact that Higgs fields, defining morphisms of vector bundles over R^2, are not holomorphic in the generic case. Finally, we introduce BPS vortex equations in N=4 super Yang-Mills theory and show that they have the same feature.Comment: 14 pages; v2: typos fixed, published versio

    Singular potentials and annihilation

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    We discuss the regularization of attractive singular potentials αs/rs-\alpha _{s}/r^{s}, s2s\geq 2 by infinitesimal imaginary addition to interaction constant αs=αs±i0\alpha_{s}=\alpha_{s}\pm i0. Such a procedure enables unique definition of scattering observables and is equal to an absorption (creation) of particles in the origin. It is shown, that suggested regularization is an analytical continuation of the scattering amplitudes of repulsive singular potential in interaction constant αs\alpha_{s}. The nearthreshold properties of regularized in a mentioned way singular potential are examined. We obtain expressions for the scattering lengths, which turn to be complex even for infinitesimal imaginary part of interaction constant. The problem of perturbation of nearthreshold states of regular potential by a singular one is treated, the expressions for level shifts and widths are obtained. We show, that the physical sense of suggested regularization is that the scattering observables are insensitive to any details of the short range modification of singular potential, if there exists sufficiently strong inelastic short range interaction. In this case the scattering observables are determined by solutions of Schrodinger equation with regularized potential (αs±i0)/rs-(\alpha_{s}\pm i0)/r^{s}. We point out that the developed formalism can be applied for the description of systems with short range annihilation, in particular low energy nucleon-antinucleon scattering.Comment: 10 page

    Расчет тепловой сети г. Нижнего Новгорода с точки зрения возникновения возможных аварийных ситуаций

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    In an article are given numerical calculations of existing heat — supply system from the point of view of emergency situations arising and is given analysis of possebility of system functioning in future.Проведены численные расчеты существующей тепловой сети с точки зрения возникновения возможных аварийных ситуаций и выполнен анализ возможности функционирования сети в дальнейшем
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