17,093 research outputs found
Spacecraft charging: incoming and outgoing electrons
This paper presents an overview of the roles played by incoming and outgoing
electrons in spacecraft surface and stresses the importance of surface
conditions for spacecraft charging. The balance between the incoming electron
current from the ambient plasma and the outgoing currents of secondary
electrons, backscattered electrons, and photoelectrons from the surfaces
determines the surface potential. Since surface conditions significantly affect
the outgoing currents, the critical temperature and the surface potential are
also significantly affected. As a corollary, high level differential charging
of adjacent surfaces with very different surface conditions is a space hazard.Comment: 4 pages, contribution to the Joint INFN-CERN-EuCARD-AccNet Workshop
on Electron-Cloud Effects: ECLOUD'12; 5-9 Jun 2012, La Biodola, Isola d'Elba,
Ital
A cascaded coding scheme for error control
A cascade coding scheme for error control is investigated. The scheme employs a combination of hard and soft decisions in decoding. Error performance is analyzed. If the inner and outer codes are chosen properly, extremely high reliability can be attained even for a high channel bit-error-rate. Some example schemes are evaluated. They seem to be quite suitable for satellite down-link error control
On the direct shock wave problem. a modified theory /final report on bodies with spherical nose/
Modification of mathematical approach to general body problem for investigating direct shock wave problem for bodies with spherical nos
Density Dependence of Transport Coefficients from Holographic Hydrodynamics
We study the transport coefficients of Quark-Gluon-Plasma in finite
temperature and finite baryon density. We use AdS/QCD of charged AdS black hole
background with bulk-filling branes identifying the U(1) charge as the baryon
number. We calculate the diffusion constant, the shear viscosity and the
thermal conductivity to plot their density and temperature dependences.
Hydrodynamic relations between those are shown to hold exactly. The diffusion
constant and the shear viscosity are decreasing as a function of density for
fixed total energy. For fixed temperature, the fluid becomes less diffusible
and more viscous for larger baryon density.Comment: LaTeX, 1+33 pages, 6 figures, references adde
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