174,942 research outputs found

    Low gravity phase separator

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    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

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    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 Hα\alpha 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 Hα\alpha 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 ∼20\sim20 M⊙_{\odot} yr−1^{-1}, 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 ∼2×107\sim2\times 10^7 M⊙_{\odot} 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

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    http://www.heinonline.org/HOL/Page?handle=hein.journals/ucollr39&div=24&collection=journal

    The Close Corporation and the Colorado Lawyer

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    http://www.heinonline.org/HOL/Page?handle=hein.journals/ucollr39&div=24&collection=journal

    Compactification of a map which is mapped to itself

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    We prove that if T:X→XT: X \to X is a selfmap of a set XX such that \bigcap \{T^{n}X: n\in N}\} is a one-point set, then the set XX can be endowed with a compact Hausdorff topology so that TT is continuous.Comment: 5 page

    Wolf-Rayets in IC10: Probing the Nearest Starburst

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    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

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    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

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    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

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    Emissivity coatings for low temperature spacecraft radiator

    Characterization of GTA weldments in 10Ni-8CO-2Cr-1MO steel

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    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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