30,811 research outputs found
Solar array strip and a method for forming the same
A flexible solar array strip is formed by providing printed circuitry between flexible layers of a nonconductive material, depositing solder pads on the printed circuitry, and storing the resulting substrate on a drum from which it is then withdrawn and advanced along a linear path. Solderless solar cells are serially transported into engagement with the pads and are infrared radiation to melt the solder and attach the cells to the circuitry. Excess flux is cleaned from the solar cells which are then encapsulated in a protective coating. The resulting array is then wound on a drum
Hydrogen maser for field use Technical report, Jun. 27, 1966 - Jan. 30, 1968
Hydrogen maser for field use with cavity and bulb design of maser for satellite application
Eddington limited starbursts in the central 10pc of AGN, and the Torus in NGC1068
We present results from a survey of nearby AGN using the near infrared
adaptive optics integral field spectrograph SINFONI. These data enable us to
probe the distribution and kinematics of the gas and stars at spatial
resolutions as small as 0.085arcsec. We find strong evidence for recent but
short lived starbursts residing in very dense nuclear disks. On scales of less
than 10pc these would have reached Eddington-limited luminosities when active,
perhaps accounting for their short duration. In addition, for NGC1068 at a
resolution of 6pc, we present direct observations of molecular gas close around
the AGN which we identify with the obscuring torus.Comment: Conference proceedings to appear in "The Central Engine of Active
Galactic Nuclei", ed. L. C. Ho and J.-M. Wang (San Francisco: ASP
Quenching of hadron spectra in media
We determine how the yield of large transverse momentum hadrons is modified
due to induced gluon radiation off a hard parton traversing a QCD medium. The
quenching factor is formally a collinear- and infrared-safe quantity and can be
treated perturbatively. In spite of that, in the region of practical
interest, its value turns out to be extremely sensitive to large distances and
can be used to unravel the properties of dense quark-gluon final states
produced in heavy ion collisions. We also find that the standard modelling of
quenching by shifting in the hard parton cross section by the mean
energy loss is inadequate.Comment: 20 pp, 5 eps figure
Explanation of 100-fold reduction of spectral shifts for hydrogen on helium films
We show that helium film-mediated hydrogen-hydrogen interactions account for
a two orders of magnitude discrepancy between previous theory and recent
experiments on cold collision shifts in spin-polarized hydrogen adsorbed on a
helium film. These attractive interactions also explain the anomalous
dependence of the cold collision frequency shifts on the He covering of the
film. Our findings suggest that the gas will become mechanically unstable
before reaching the Kosterlitz-Thouless transition unless the experiment is
performed in a drastically different regime, for example with a much different
helium film geometry.Comment: 4+ pages, 1 figure (3 subfigures), revtex
System reliability analysis through corona testing
A corona vacuum test facility for nondestructive testing of power system components was built in the Reliability and Quality Engineering Test Laboratories at the NASA Lewis Research Center. The facility was developed to simulate operating temperature and vacuum while monitoring corona discharges with residual gases. The facility is being used to test various high-voltage power system components
The Large Area Pulsed Solar Simulator (LAPSS)
The Large Area Pulsed Solar Simulator (LAPSS) has been installed at JPL. It is primarily intended to be used to illuminate and measure the electrical performance of photovoltaic devices. The simulator, originally manufactured by Spectrolab, Sylmar, CA, occupies an area measuring about 3 m wide x 12 m long. The data acquisition and data processing subsystems have been modernized. Tests on the LAPSS performance resulted in better than plus or minus 2 percent uniformity of irradiance at the test plane and better than plus or minus 0.3 percent measurement repeatability after warm-up. Glass absorption filters reduce the ultraviolet light emitted from the xenon flash lamps. This results in a close match to three different standard airmass zero and airmass 1.5 spectral irradiances. The 2-ms light pulse prevents heating of the device under test, resulting in more reliable temperature measurements. Overall, excellent electrical performance measurements have been made of many different types and sizes of photovoltaic devices. Since the original printing of this publication, in 1993, the LAPSS has been operational and new capabilities have been added. This revision includes a new section relating to the installation of a method to measure the I-V curve of a solar cell or array exhibiting a large effective capacitance. Another new section has been added relating to new capabilities for plotting single and multiple I-V curves, and for archiving the I-V data and test parameters. Finally, a section has been added regarding the data acquisition electronics calibration
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