93,032 research outputs found
Phase detector assembly Patent
Detector assembly for discriminating first signal with respect to presence or absence of second signal at time of occurrence of first signa
Borel singularities at small x
D.I.S. at small Bjorken is considered within the dipole cascade
formalism. The running coupling in impact parameter space is introduced in
order to parametrize effects that arise from emission of large size dipoles.
This results in a new evolution equation for the dipole cascade. Strong
coupling effects are analyzed after transforming the evolution equation in
Borel () space. The Borel singularities of the solution are discussed first
for the universal part of the dipole cascade and then for the specific process
of D.I.S. at small . In the latter case the leading infrared renormalon is
at indicating the presence of power corrections for the
small- structure functions.Comment: 5 pages, Latex (Talk presented at DIS'97, Chicago, IL
Qualification Phase for the Applications Technology Satellite Apogee Rocket Motor Technical Memorandum, Jul. - Aug. 1966
Qualifications tests on applications technology satellite apogee rocket motor assemblie
Investigation of parabolic computational techniques for internal high-speed viscous flows
A feasibility study was conducted to assess the applicability of an existing parabolic analysis (ADD-Axisymmetric Diffuser Duct), developed previously for subsonic viscous internal flows, to mixed supersonic/subsonic flows with heat addition simulating a SCRAMJET combustor. A study was conducted with the ADD code modified to include additional convection effects in the normal momentum equation when supersonic expansion and compression waves were present. It is concluded from the present study that for the class of problems where strong viscous/inviscid interactions are present a global iteration procedure is required
Directly Measured Limit on the Interplanetary Matter Density from Pioneer 10 and 11
The Pioneer 10 and 11 spacecraft had exceptional deep-space navigational
capabilities. The accuracies of their orbit reconstruction were limited,
however, by a small, anomalous, Doppler frequency drift that can be interpreted
as an acceleration of (8.74 +/- 1.33) x 10^{-8} cm/s^2 directed toward the Sun.
We investigate the possibility that this anomaly could be due to a drag on the
spacecraft from their passing through the interplanetary medium. Although this
mechanism is an appealing one, the existing Pioneer radiometric data would
require an unexpectedly high mass density of interplanetary dust for this
mechanism to work. Further, the magnitude of the density would have to be
nearly constant at distances ~ 20-70 AU. Therefore, it appears that such an
explanation is very unlikely, if not ruled out. Despite this, the measured
frequency drift by itself places a directly-measured, model-independent limit
of \lessim 3 x 10^{-19} g/cm^3 on the mass density of interplanetary dust in
the outer(~20-70 AU) solar system. Lower experimental limits can be placed if
one presumes a model that varies with distance. An example is the limit \lessim
6 x 10^{-20} g/cm^3 obtained for the model with an axially-symmetric density
distribution that falls off as the inverse of the distance. We emphasize that
the limits obtained are experimentally-measured, in situ limits. A mission to
investigate the anomaly would be able to place a better limit on the density,
or perhaps even to measure it.Comment: 16 pages, 2 figures, publication versio
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