49,839 research outputs found

    Rocketdyne's advanced coal slurry pumping program

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    The Rocketdyne Division of Rockwell International Corporation is conducting a program for the engineering, fabrication, and testing of an experimental/prototype high-capacity, high-pressure centrifugal slurry feed pump for coal liquefaction purposes. The abrasion problems in a centrifugal slurry pump are primarily due to the manner in which the hard, solid particles contained in the slurry are transported through the hydraulic flow passages within the pump. The abrasive particles can create scraping, grinding, cutting, and sandblasting effects on the various exposed parts of the pump. These critical areas involving abrasion and impact erosion wear problems in a centrifugal pump are being addressed by Rocketdyne. The mechanisms of abrasion and erosion are being studied through hydrodynamic analysis, materials evaluation, and advanced design concepts

    Synthesising and utilising complex evidence to inform policy in education and health.

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    Oslo, Norway, May 19 to 21, 200

    Bounds on Cubic Lorentz-Violating Terms in the Fermionic Dispersion Relation

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    We study the recently proposed Lorentz-violating dispersion relation for fermions and show that it leads to two distinct cubic operators in the momentum. We compute the leading order terms that modify the non-relativistic equations of motion and use experimental results for the hyperfine transition in the ground state of the 9Be+{}^9\textrm Be^+ ion to bound the values of the Lorentz-violating parameters η1\eta_1 and η2\eta_2 for neutrons. The resulting bounds depend on the value of the Lorenz-violating background four-vector in the laboratory frame.Comment: Revtex 4, four pages. Version to match the one to appear in Physical Review

    Spin-Seebeck effect in a strongly interacting Fermi gas

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    We study the spin-Seebeck effect in a strongly interacting, two-component Fermi gas and propose an experiment to measure this effect by relatively displacing spin up and spin down atomic clouds in a trap using spin-dependent temperature gradients. We compute the spin-Seebeck coefficient and related spin-heat transport coefficients as functions of temperature and interaction strength. We find that when the inter-spin scattering length becomes larger than the Fermi wavelength, the spin-Seebeck coefficient changes sign as a function of temperature, and hence so does the direction of the spin-separation. We compute this zero-crossing temperature as a function of interaction strength and in particular in the unitary limit for the inter-spin scattering
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