40,000 research outputs found
Double hinged flap Patent
Double hinged flap for boundary layer control over trailing edges of wing
Dual differential interferometer
A dual two-beam differential interferometer that measures both the amplitude and orientation of propagating, broadband surface acoustic waves is disclosed. Four beams are focused on a surface. The four reflected beams are separated into two pairs. The two pairs are detected to produce two signals that are used to compute amplitude and orientation
Skylab food system
A review of the Skylab food system requirements, package designs, and launch configurations was presented. In-flight anomalies were discussed, and between-mission changes in design were described. A discussion of support for Skylab 3 and Skylab 4 mission extensions and of new items launched on these missions is included
Calculation of wind-driven surface currents in the North Atlantic Ocean
Calculations to simulate the wind driven near surface currents of the North Atlantic Ocean are described. The primitive equations were integrated on a finite difference grid with a horizontal resolution of 2.5 deg in longitude and latitude. The model ocean was homogeneous with a uniform depth of 100 m and with five levels in the vertical direction. A form of the rigid-lid approximation was applied. Generally, the computed surface current patterns agreed with observed currents. The development of a subsurface equatorial countercurrent was observed
The Extraordinary Infrared Spectrum of NGC 1222 (Mkn 603)
The infrared spectra of starburst galaxies are dominated by the
low-excitation lines of [NeII] and [SIII], and the stellar populations deduced
from these spectra appear to lack stars larger than about 35 Msun. The only
exceptions to this result until now were low metallicity dwarf galaxies. We
report our analysis of the mid-infrared spectra obtained with IRS on Spitzer of
the starburst galaxy NGC 1222 (Mkn 603). NGC 1222 is a large spheroidal galaxy
with a starburst nucleus that is a compact radio and infrared source, and its
infrared emission is dominated by the [NeIII] line. This is the first starburst
of solar or near-solar metallicity, known to us, which is dominated by the
high-excitation lines and which is a likely host of high mass stars. We model
the emission with several different assumptions as to the spatial distibution
of the high- and low-excitation lines and find that the upper mass cutoff in
this galaxy is 40-100 Msun.Comment: accepted, Astronomical Journal. 29 pp, 4 figures. In replacement
version an acknowledgment to NRAO is adde
Improved smoke generator for low-speed wind tunnels
Device incorporates kerosene vaporization concept by electrically heating tubes that carry kerosene down the probe, smoke is emitted from orifices at probe's end. Neither the low concentration of kerosene vapor nor the 50 Vdc power supply constitutes a safety hazard
ASCA observations of type-2 Seyfert galaxies: II. The Importance of X-ray Scattering and Reflection
We discuss the importance of X-ray scattering and Compton reflection in
type-2 Seyfert galaxies, based upon the analysis of ASCA observations of 25
such sources. Consideration of the iron Kalpha, [O III] line and X-ray
variability suggest that NGC 1068, NGC 4945, NGC 2992, Mrk 3, Mrk 463E and Mrk
273 are dominated by reprocessed X-rays. We examine the properties of these
sources in more detail.
We find that the iron Kalpha complex contains significant contributions from
neutral and high-ionization species of iron. Compton reflection, hot gas and
starburst emission all appear to make significant contributions to the observed
X-ray spectra.
Mrk 3 is the only source in this subsample which does not have a significant
starburst contamination. The ASCA spectrum below 3 keV is dominated by hot
scattering gas with U_X ~ 5, N_H ~ 4 x 10^23 cm^-2. This material is more
highly ionized than the zone of material comprising the warm absorber seen in
Seyfert~1 galaxies, but may contain a contribution from shock-heated gas
associated with the jet. Estimates of the X-ray scattering fraction cover 0.25
- 5%. The spectrum above 3 keV appears to be dominated by a Compton reflection
component although there is evidence that the primary continuum component
becomes visible close to 10 keV.Comment: 27 pages, 6 figures. LaTeX with encapsulated postscript. To appear in
the Astrophysical Journal. Also available via
http://lheawww.gsfc.nasa.gov/~george/papers/gnt_s2p2/abstract.htm
The influence of grazing on surface climatological variables of tallgrass prairie
Mass and energy exchange between most grassland canopies and the atmosphere are mediated by grazing activities. Ambient temperatures can be increased or decreased by grazers. Data have been assembled from simulated grazing experiments on Konza Prairie Research Natural Area and observations on adjacent pastures grazed by cattle show significant changes in primary production, nutrient content, and bidirectional reflectance characteristics as a function of grazing intensity. The purpose of this research was to provide algorithms that would allow incorporation of grazing effects into models of energy budgets using remote sensing procedures. The approach involved: (1) linking empirical measurements of plant biomass and grazing intensities to remotely sensed canopy reflectance, and (2) using a higher resolution, mechanistic grazing model to derive plant ecophysiological parameters that influence reflectance and other surface climatological variables
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