19,644 research outputs found
High-gain antenna with singly-curved reflector
Reflector collects energy over large region of space and focuses it toward small region where antenna feed is located. When incident energy is in form of plane wave, logical choice for shape of reflecting surface is paraboloid which converts plane wave into spherical wave that converges at a point
Dual waveguide mode source having control means for adjusting the relative amplitude of two modes Patent
Dual waveguide mode source for controlling amplitudes of two mode
Prediction of thermal radiation from a rocket's exhaust plume
Data from absorption coefficients and fine-structure parameters measured for water vapor have been incorporated in an analytic program useful in evaluating heating by radiation from the exhaust plume of a large rocket
Some NASA contributions to the use of plasma jet technology in chemical processing
NASA contributions to use of plasma jet technology in chemical processin
Prediction of total emissivity of nitrogen- broadened and self-broadened hot water vapor
Total emissivity predicted for nitrogen-broadened and self-broadened hot water vapo
Combining NLO QCD and Electroweak Radiative Corrections to W boson Production at Hadron Colliders in the POWHEG Framework
The precision measurement of the mass of the boson is an important goal
of the Fermilab Tevatron and the CERN Large Hadron Collider (LHC). It requires
accurate theoretical calculations which incorporate both higher-order QCD and
electroweak corrections, and also provide an interface to parton-shower Monte
Carlo programs which make it possible to realistically simulate experimental
data. In this paper, we present a combination of the full
electroweak corrections of {\tt WGRAD2}, and the next-to-leading order QCD
radiative corrections to production in hadronic collisions in a
single event generator based on the {\tt POWHEG} framework, which is able to
interface with the parton-shower Monte Carlo programs {\tt Pythia} and {\tt
Herwig}. Using this new combined QCD+EW Monte Carlo program for production
we provide numerical results for total cross sections and kinematic
distributions of relevance to the mass measurement at the Tevatron and the
LHC for the processes . In
particular, we discuss the impact of EW corrections in the presence of QCD
effects when including detector resolution effects.Comment: 32 pages, 28 postscript figures, typos fixed, plot on the right-hand
side of Fig.12 replaced with results from a higher statistics run, note adde
Composite seal for turbomachinery
A gas path seal suitable for use with a turbine engine or compressor is provided. A shroud wearable or abradable by the abrasion of the rotor blades of the turbine or compressor protects the rotor blades. A compliant backing surrounds the shroud. The backing may be made of corrugated sheets or the like with adjacent layers having off-set corrugations, with axes of the folds parallel to the rotor axis. The sheets may be bonded together at points of contact by brazing, welding or the like. In another embodiment a compliant material is covered with a thin ductile layer. A mounting fixture surrounds the backing
Low-loss, circularly-polarized dichroic plate
Dichroic plate has orthogonally-disposed, loaded dipole apertures with their orientations arranged so as to cancel cross-coupling effects which would otherwise result in power loss to circularly polarized signal
Low loss dichroic plate
A low loss dichroic plate is disclosed for passing radiation within a particular frequency band and reflecting radiation outside of that frequency band. The dichroic plate is comprised of a configuration of dipole elements defined by slots formed in a conductive plate. The slots are dimensioned so as to pass radiation of a selected frequency and are shaped so as to minimize the relationship between that frequency and the tilt angle of the plate relative to the direction of radiation. The slots are arranged so as to minimize signal power loss due to cross polarization effects
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