248 research outputs found

    Global gyrokinetic simulations of intrinsic rotation in ASDEX Upgrade Ohmic L-mode plasmas

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    Non-linear, radially global, turbulence simulations of ASDEX Upgrade (AUG) plasmas are performed and the nonlinear generated intrinsic flow shows agreement with the intrinsic flow gradients measured in the core of Ohmic L-mode plasmas at nominal parameters. Simulations utilising the kinetic electron model show hollow intrinsic flow profiles as seen in a predominant number of experiments performed at similar plasma parameters. In addition, significantly larger flow gradients are seen than in a previous flux-tube analysis (Hornsby et al {\it Nucl. Fusion} (2017)). Adiabatic electron model simulations can show a flow profile with opposing sign in the gradient with respect to a kinetic electron simulation, implying a reversal in the sign of the residual stress due to kinetic electrons. The shaping of the intrinsic flow is strongly determined by the density gradient profile. The sensitivity of the residual stress to variations in density profile curvature is calculated and seen to be significantly stronger than to neoclassical flows (Hornsby et al {\it Nucl. Fusion} (2017)). This variation is strong enough on its own to explain the large variations in the intrinsic flow gradients seen in some AUG experiments. Analysis of the symmetry breaking properties of the turbulence shows that profile shearing is the dominant mechanism in producing a finite parallel wave-number, with turbulence gradient effects contributing a smaller portion of the parallel wave-vector

    Low resistance Cu[3]Ge compounds formation by the lowtemperature treatment of Cu/Ge system in atomic hydrogen

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    The research deals with the regularities for Cu[3]Ge compound formation under the low temperature treatment of a double-layer Cu/Ge system deposited on i-GaAs substrate in atomic hydrogen flow. The treatment of a Cu/Ge/i-GaAs system with layer thicknesses, respectively, of 122 and 78 nm, in atomic hydrogen with a flow rate of 10{15} at.·сm{-2} s{-1} for a duration of 2.5{-10} min at room temperature, leads to an interdiffusion of Cu and Ge and formation of a polycrystalline film containing stoichiometric phase Cu[3]Ge. The film consists of vertically oriented grains of dimensions 100-150 nm and has a minimum specific resistance of 4.5 [mu omega] сm. Variation in the treatment duration of Cu/Ge/i-GaAs samples in atomic hydrogen affects Cu and Ge distribution profiles, the phase composition of films formed, and the specific resistance of the latter. As observed, Cu3Ge compound synthesis at room temperature demonstrates the stimulative effects characteristic of atomic hydrogen treatment for both Cu and Ge diffusion and for the chemical reaction of Cu[3]Ge compound generation. Activation of these processes can be conditioned by the energy released during recombination of hydrogen atoms adsorbed on the surface of a Cu/Ge/i-GaAs sample

    Building Heat-insulating Materials Based on the Products of the Transesterification of Polyethylene Terephthalate and Dibutyltin Dilaurate

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    In this paper, we offered a technological basis for production of heat-insulating polyurethane materials based on the aromatic polyester - the product of transesterification of polyethylene terephthalate and corrective additive - dibutyltin dilaurate. Also, we presented the formulation and properties of the developed polyurethanes

    Study of the process e+eppˉe^+e^-\to p\bar{p} in the c.m. energy range from threshold to 2 GeV with the CMD-3 detector

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    Using a data sample of 6.8 pb1^{-1} collected with the CMD-3 detector at the VEPP-2000 e+ee^+e^- collider we select about 2700 events of the e+eppˉe^+e^- \to p\bar{p} process and measure its cross section at 12 energy ponts with about 6\% systematic uncertainty. From the angular distribution of produced nucleons we obtain the ratio GE/GM=1.49±0.23±0.30|G_{E}/G_{M}| = 1.49 \pm 0.23 \pm 0.30

    Non-Newtonian Couette-Poiseuille flow of a dilute gas

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    The steady state of a dilute gas enclosed between two infinite parallel plates in relative motion and under the action of a uniform body force parallel to the plates is considered. The Bhatnagar-Gross-Krook model kinetic equation is analytically solved for this Couette-Poiseuille flow to first order in the force and for arbitrary values of the Knudsen number associated with the shear rate. This allows us to investigate the influence of the external force on the non-Newtonian properties of the Couette flow. Moreover, the Couette-Poiseuille flow is analyzed when the shear-rate Knudsen number and the scaled force are of the same order and terms up to second order are retained. In this way, the transition from the bimodal temperature profile characteristic of the pure force-driven Poiseuille flow to the parabolic profile characteristic of the pure Couette flow through several intermediate stages in the Couette-Poiseuille flow are described. A critical comparison with the Navier-Stokes solution of the problem is carried out.Comment: 24 pages, 5 figures; v2: discussion on boundary conditions added; 10 additional references. Published in a special issue of the journal "Kinetic and Related Models" dedicated to the memory of Carlo Cercignan

    THERMOGRAPHIC SURVEY OF INDUSTRIAL ENTERPRISES BY THE RESULTS OF THE ENERGY AUDIT

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    The article presents the data of the energy survey of Pobedit OJSC. Thermovision analysis performed. The results of thermographic shooting are presented.В статье представлены данные энергетического обследования ОАО «Победит». Выполнен тепловизионный анализ. Представлены результаты термографической съемки
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