50,342 research outputs found
Wind tunnel model and method
The design and development of a wind tunnel model equipped with pressure measuring devices are discussed. The pressure measuring orifices are integrally constructed in the wind tunnel model and do not contribute to distortions of the aerodynamic surface. The construction of a typical model is described and a drawing of the device is included
The spectral characteristics of the 2dFGRS-NVSS galaxies
We have analysed the 2dF spectra of a sample of galaxies common to the 2dF
galaxy redshift survey (2dFGRS, Colless 1999) and the NRAO VLA sky survey
(NVSS, Condon et al. 1998). Our sample comprises 88 galaxies selected by Sadler
et al. (1999) from 30 2dFGRS fields observed in 1998. In this paper we discuss
how this and future, much larger, samples of 2dFGRS-NVSS galaxies can be
interpreted via analysis of those galaxies with strong narrow emission lines.
Using diagnostic line ratio measurements we confirm the majority of the eyeball
classifications of Sadler et al. (1999), although many galaxies show evidence
of being `composite' galaxies - a mixture of AGN plus starburst components.Comment: 11 pages, 5 figures, accepted for publication in PAS
Higgs Boson Production with Bottom Quarks at Hadron Colliders
We present results for the production cross section of a Higgs Boson with a
pair of bottom/anti-bottom quarks, including next-to-leading order (NLO) QCD
corrections.Comment: 3 pages, 2 figures, uses ws-ijmpa.cls. Talk given by C.B. Jackson at
the Meeting of the Division of Particles and Fields (DPF2004) in Riverside,
CA, August 26-31, 200
Manipulating Bose-Einstein condensed atoms in toroidal traps
We consider Bose-Einstein condensed atoms confined in a toroidal trap. We
demonstrate that under conditions of one-dimensional behavior, the density
distribution of the atoms may be exponentially localized/delocalized, even for
very small variations in the trapping potential along the torus. This
observation allows one to control the atom density externally via slight
modifications of the trapping potential. For similar reasons, small
irregularities of the trap may also have a very pronounced effect on the
density of the cloud.Comment: 4 pages, RevTex, 2 figure
Metric half-span model support system
A model support system used to support a model in a wind tunnel test section is described. The model comprises a metric, or measured, half-span supported by a nonmetric, or nonmeasured half-span which is connected to a sting support. Moments and forces acting on the metric half-span are measured without interference from the support system during a wind tunnel test
Measuring gravitational lens time delays using low-resolution radio monitoring observations
Obtaining lensing time delay measurements requires long-term monitoring
campaigns with a high enough resolution (< 1 arcsec) to separate the multiple
images. In the radio, a limited number of high-resolution interferometer arrays
make these observations difficult to schedule. To overcome this problem, we
propose a technique for measuring gravitational time delays which relies on
monitoring the total flux density with low-resolution but high-sensitivity
radio telescopes to follow the variation of the brighter image. This is then
used to trigger high-resolution observations in optimal numbers which then
reveal the variation in the fainter image. We present simulations to assess the
efficiency of this method together with a pilot project observing radio lens
systems with the Westerbork Synthesis Radio Telescope (WSRT) to trigger Very
Large Array (VLA) observations. This new method is promising for measuring time
delays because it uses relatively small amounts of time on high-resolution
telescopes. This will be important because instruments that have high
sensitivity but limited resolution, together with an optimum usage of followup
high-resolution observations from appropriate radio telescopes may in the
future be useful for gravitational lensing time delay measurements by means of
this new method.Comment: 10 pages, 7 figures, accepted by MNRA
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