174,942 research outputs found
Low gravity phase separator
An apparatus is described for phase separating a gas-liquid mixture as might exist in a subcritical cryogenic helium vessel for cooling a superconducting magnet at low gravity such as in planetary orbit, permitting conservation of the liquid and extended service life of the superconducting magnet
Dynamics and star formation activity of CG J1720-67.8 unveiled through integral field spectroscopy and radio observations
CG J1720-67.8 is an ultra compact group of several galaxies with a low
velocity dispersion, and displaying the hallmarks of mutual interaction and
possible tidal dwarf galaxy formation. In hierarchical models, the system is a
possible precursor to a massive elliptical galaxy. In this paper, we use new
optical integral field spectroscopic and radio observations to investigate the
evolutionary status of the group in more detail: global star-formation rates
are estimated using H and 1.4 GHz radio continuum measurements; H {\sc
i} observations provide an upper limit to the global neutral gas content;
optical broadband colours and spectra provide ages and stellar mass estimates
for the tidal dwarf candidates; the bidimensional H velocity field is
used to trace the kinematics of the group and its members, which are compared
with numerical simulations of galaxy encounters. The observations suggest a
model in which multiple interactions have occurred, with the latest strong
encounter involving at least two major components within the last 200 Myr.
Debris from the encounter fuels ongoing star formation at the global level of
M yr, with self-gravity within the tidal tail
possibly providing a mechanism to enhance the star formation rate of the tidal
dwarf candidates, with bursts of star-formation in clumps of mass M appearing within the last 10 Myr. The amount of time required
for final merging of all group components remains uncertain.Comment: 22 pages, 16 figures. Accepted for publication in MNRA
The Close Corporation and the Colorado Lawyer
http://www.heinonline.org/HOL/Page?handle=hein.journals/ucollr39&div=24&collection=journal
The Close Corporation and the Colorado Lawyer
http://www.heinonline.org/HOL/Page?handle=hein.journals/ucollr39&div=24&collection=journal
Compactification of a map which is mapped to itself
We prove that if is a selfmap of a set such that \bigcap
\{T^{n}X: n\in N}\} is a one-point set, then the set can be endowed with a
compact Hausdorff topology so that is continuous.Comment: 5 page
Wolf-Rayets in IC10: Probing the Nearest Starburst
IC10 is the nearest starburst galaxy, as revealed both by its Halpha surface
brightness and the large number of Wolf-Rayet stars (WRs) per unit area. The
relative number of known WC- to WN-type WRs has been thought to be unusually
high (~2), unexpected for IC10's metallicity. In this Letter we report the
first results of a new and deeper survey for WRs in IC10. We sucessfully
detected all of the spectroscopically known WRs, and based upon comparisons
with a neighboring control field, estimate that the total number of WRs in IC10
is about 100. We present spectroscopic confirmation of two of our WR
candidates, both of which are of WN type. Our photometric survey predicts that
the actual WC/WN ratio is ~0.3. This makes the WC/WN ratio of IC 10 consistent
with that expected for its metallicity, but greatly increases the already
unusually high number of WRs, resulting in a surface density that is about 20
times higher than in the LMC. If the majority of these candidates are
spectroscopically confirmed, IC10 must have an exceptional population of high
mass stars.Comment: Accepted by ApJL; only minor correction in this versio
A correlation of optical, radio, and interplanetary records of solar events Final report
Correlation of optical, radio, and interplanetary records of solar event
Effect of fuel properties on performance of single aircraft turbojet combustor at simulated idle, cruise, and takeoff conditions
The performance of a single-can JT8D combustor was investigated with a number of fuels exhibiting wide variations in chemical composition and volatility. Performance parameters investigated were combustion efficiency, emissions of CO, unburned hydrocarbons and nitrogen oxides, as well as liner temperatures and smoke. The most pronounced effects of changes in fuel composition were observed at simulated cruise and takeoff conditions where smoke and liner temperatures increased significantly as the hydrogen content of the fuel decreased. At the simulated idle condition, emissions of CO and unburned hydrocarbons increased slightly and, accordingly, combustion efficiencies decreased slightly as the hydrogen content of the fuels decreased
Emissivity coatings for low-temperature space radiators Quarterly progress report no. 1, 1 Jul. - 30 Sep. 1965
Emissivity coatings for low temperature spacecraft radiator
Characterization of GTA weldments in 10Ni-8CO-2Cr-1MO steel
This study of 10Ni-8Co-2Cr-1Mo steel includes evaluations of tensile, impact, hardness, fracture toughness properties, and metallographic features. Base plate and three weldments in one-inch thicknesses were examined to compare as-welded properties with those obtained after reaging, and results of welding the 10%Ni alloy with 9-4-20 wire as opposed to a matching weld wire composition. Critical crack sizes are calculated for the material. The most desirable weld properties are obtained using the matching weld wire and a reaging cycle. However, the improvement gained through reaging is probably not sufficient to justify the additional cost for most practical applications
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