32,960 research outputs found

    Space Storable Rocket Technology (SSRT) basic program

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    The Space Storable Rocket Technology Program (SSRT) was conducted to establish a technology for a new class of high performance and long life bipropellant engines using space storable propellants. The results are described. Task 1 evaluated several characteristics for a number of fuels to determine the best space storable fuel for use with LO2. The results indicated that LO2-N2H4 is the best propellant combination and provides the maximum mission/system capability maximum payload into GEO of satellites. Task 2 developed two models, performance and thermal. The performance model indicated the performance goal of specific impulse greater than or = 340 seconds (sigma = 204) could be achieved. The thermal model was developed and anchored to hot fire test data. Task 3 consisted of design, fabrication, and testing of a 200 lbf thrust test engine operating at a chamber pressure of 200 psia using LO2-N2H4. A total of 76 hot fire tests were conducted demonstrating performance greater than 340 (sigma = 204) which is a 25 second specific impulse improvement over the existing highest performance flight apogee type engines

    Non-Gaussian Correlations in the McLerran-Venugopalan Model

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    We argue that the statistical weight function W[rho] appearing in the McLerran-Venugopalan model of a large nucleus is intrinsically non-Gaussian, even if we neglect quantum corrections. Based on the picture where the nucleus of radius R consists of a collection of color-neutral nucleons, each of radius a<<R, we show that to leading order in alpha_s and a/R only the Gaussian part of W[rho] enters into the final expression for the gluon number density. Thus, the existing results in the literature which assume a Gaussian weight remain valid.Comment: 21 pages with 4 figures (revtex

    Rotational States of Magnetic Molecules

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    We study a magnetic molecule that exhibits spin tunneling and is free to rotate about its anisotropy axis. Exact low-energy eigenstates of the molecule that are superpositions of spin and rotational states are obtained. We show that parameter α=2(S)2/(IΔ)\alpha = 2(\hbar S)^2/(I\Delta) determines the ground state of the molecule. Here S\hbar S is the spin, II is the moment of inertia, and Δ\Delta is the tunnel splitting. The magnetic moment of the molecule is zero at ααc\alpha \alpha_c. At α\alpha \to \infty the spin of the molecule localizes in one of the directions along the anisotropy axis.Comment: 4 pages, 3 figure
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