33,355 research outputs found
Space Storable Rocket Technology (SSRT) basic program
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
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
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 determines the ground state of
the molecule. Here is the spin, is the moment of inertia, and
is the tunnel splitting. The magnetic moment of the molecule is zero
at . At the spin of the molecule localizes in one of
the directions along the anisotropy axis.Comment: 4 pages, 3 figure
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