1,322 research outputs found
Infrared Supernova Remnants in the Spitzer GLIMPSE Field
We have searched for infrared emission from supernova remnants (SNRs)
included in the Spitzer Galactic Legacy Infrared Mid-Plane Survey
Extraordinaire (GLIMPSE) field. At the positions of 100 known SNRs, we made
3.6, 4.5, 5.8, and 8.0 um band images covering the radio continuum emitting
area of each remnant. In-depth examinations of four band images based on the
radio continuum images of SNRs result in the identification of sixteen infrared
SNRs in the GLIMPSE field. Eight SNRs show distinct infrared emission in nearly
all the four bands, and the other eight SNRs are visible in more than one band.
We present four band images for all identified SNRs, and RGB-color images for
the first eight SNRs. These images are the first high resolution (<2") images
with comparative resolution of the radio continuum for SNRs detected in the
mid-infrared region. The images typically show filamentary emission along the
radio enhanced SNR boundaries. Most SNRs are well identified in the 4.5 and 5.8
um bands. We give a brief description of the infrared features of the
identified SNRs.Comment: 30 pages including 24 figures, published in JKAS (Journal of the
Korean Astronomical Society
Estimation of Appropriate Process Parameters for a Plasma Electron Beam Re-Melting Process Using Finite Element Analysis
Metal additive manufacturing using electron beam melting (EBM) process applies electron beam for heating, sintering, and melting of powders to fabricate a three-dimensional component. The component may contain residual porosity internally and may be subjected to poor surface finish externally. To improve the quality of the surface finish and densification, re-melting is conducted. The purpose of this paper was to estimate the appropriate process conditions for a plasma electron beam remelting process using heat transfer finite element analyses (FEAs). The impact of the travel speed of table and thickness of the deposited part on temperature distributions were examined. The size of molten pool was estimated from the results of the thermal FEA. From the estimated size of molten pool, the travel speed of table and the hatch spacing between remelting tracks are discussed and selected as the appropriate process conditions for electron beam re-melting process from the perspective of minimum overlapping region of the molten pool
Effects of Forestland Ownership Conversion on Greenhouse Gas Emissions: The Case of South Korea
This research analyzed the effects of forestland conversion from private to public ownership on greenhouse gas emissions by quantifying the relationship between forestland ownership conversion and deforestation, and then examining the effects of the change in deforestation on greenhouse gas emissions in South Korea. Ex ante simulations forecast greenhouse gas emissions resulting from deforestation rates under the current level of national forestland and three scenarios of increased percentages of national forestland. The findings suggest that increasing the percentage of national forestland would mitigate the increase in the deforestation rate, which in turn would moderate the increase in greenhouse gas emissions.greenhouse gas emissions, Forestland Ownership, Environmental Economics and Policy, Q15, Q23, Q24, Q54,
Recycling Studies for Swine Manure Slurry Using Multi Process of Aerobic Digestion (MPAD)
This study was carried out to investigate the feasibility of Multi Process of Aerobic Digestion (MPAD) for recycling of swine manure slurry as fertilizer. MPAD consisted of three kinds of difference process which are thermophilic aerobic oxidation (TAO) system, lime solidification system, and reverse osmosis (R/O) membrane system. TAO system was studied well previously for decade. The chemical composition of the lime-treated solid fertilizer was as like that organic matter 17.4%, moisture 34.1%, N 0.9%, P 1.7%, K 0.3%, Ca 12.7%, and which was expected to be useful as acid soil amendment material. The concentrated liquid material produced by R/O membrane system was also expected as a good fertilizer for crops production and soil fertility improvement.OtherShinshu University International Symposium 2010 : Sustainable Agriculture and Environment : Asian Networks II 信州大学国際シンポジウム2010 : 持続的農業と環境 : アジアネットワークII ― アジアネットワークの発展をめざして―. 信州大学農学部, 2010, 71-77conference pape
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The Spitzer C2D Survey of Nearby Dense Cores: Jet and Molecular Outflow Associated With A Young Stellar Object in Core A of L1251
A long infrared jet has been discovered by the Spitzer c2d Legacy Program in core A of L1251. It is associated with a very embedded Class 0 object with an accretion luminosity of about 0.9 L(circle dot) derived by radiative transfer model fitting to the observed spectral energy distribution. Comparing the observed Infrared Array Camera colors along the infrared jet with those calculated from a model of an admixture of gas with a power-law temperature distribution indicates that the jet is possibly created by a paraboloidal bow shock propagating into the ambient medium of n(H(2)) = 10(5) cm(-3). In addition, the variation of the power-law index along the jet suggests that the portion of hot gas decreases with distance from the jet engine. The molecular outflow in this region has been mapped for the first time using CO data. From the calculated outflow momentum flux, a very strong lower limit to the average accretion luminosity is 3.6 sin i/cos(3) i L(circle dot), indicative of a decrease in the accretion rate with time.Korean government (MEST) 2009-0062865NRF R01-2007-000-20336-0NASA 1407, 1224608Astronom
HST Images Reveal Dramatic Changes in the Core of IRC+10216
IRC+10216 is the nearest carbon star with a very high mass-loss rate. The
existence of a binary companion has been hinted by indirect observational
evidence, such as the bipolar morphology of its nebula and a spiral-like
pattern in its circumstellar material; however, to date, no companion has been
identified. We have examined archival Hubble Space Telescope images of
IRC+10216, and find that the images taken in 2011 exhibit dramatic changes in
its innermost region from those taken at earlier epochs. The scattered light is
more spread out in 2011. After proper motion correction, the brightest peak in
2011 is close to, but not coincident with, the dominant peak in previous
epochs. A fainter point-like object was revealed at about 0.5 arcsec from this
brightest peak. We suggest that these changes at the core of IRC+10216 are
caused by dissipation of intervening circumstellar dust, as indicated by the
brightening trend in the lightcurve extracted from the Catalina photometric
survey. We tentatively identify the brightest peak in 2011 as the primary star
of IRC+10216 and the fainter point-like source as a companion. The cause of
non-detections of the companion candidate in earlier epochs is uncertain. These
identifications need to be verified by monitoring of the core of IRC+10216 at
high resolution in the future.Comment: 13 pages, 3 figures, accepted for publication in the Astrophysical
Journal Letter
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