179,162 research outputs found
Testing the blast wave model with Swift GRBs
The complex structure of the light curves of Swift GRBs has made the
identification of breaks, and the interpretation of the blast wave caused by
the burst, more difficult than in the pre-Swift era. We aim to identify breaks,
which are possibly hidden, and to constrain the blast wave parameters; electron
energy distribution, p, density profile of the circumburst medium, k, and the
continued energy injection index, q. We do so by comparing the observed
multi-wavelength light curves and X-ray spectra of our sample to the
predictions of the blast wave model.
We can successfully interpret all of the bursts in our sample of 10, except
two, within this framework and we can estimate, with confidence, the electron
energy distribution index for 6 of the sample. Furthermore we identify jet
breaks in a number of the bursts. A statistical analysis of the distribution of
p reveals that, even in the most conservative case of least scatter, the values
are not consistent with a single, universal value. The values of k suggest that
the circumburst density profiles are not drawn from only one of the constant
density or wind-like media populations.Comment: 14 pages, accepted by MNRAS after minor changes, including extension
of discussion (section 4.3
Space shuttle holddown post blast shield
The original and subsequent designs of the Solid Rocket Booster/Holddown Post blast shield assemblies and their associated hardware are described. It presents the major problems encountered during their early use in the Space Shuttle Program, during the Return-to-Flight Modification Phase, and during their fabrication and validation testing phases. The actions taken to correct the problems are discussed, along with the various concepts now being considered to increase the useful life of the blast shield
Six Noise Type Military Sound Classifier
Blast noise from military installations often has a negative impact on the quality of life of residents living in nearby communities. This negatively impacts the military's testing \& training capabilities due to restrictions, curfews, or range closures enacted to address noise complaints. In order to more directly manage noise around military installations, accurate noise monitoring has become a necessity. Although most noise monitors are simple sound level meters, more recent ones are capable of discerning blasts from ambient noise with some success. Investigators at the University of Pittsburgh previously developed a more advanced noise classifier that can discern between wind, aircraft, and blast noise, while simultaneously lowering the measurement threshold. Recent work will be presented from the development of a more advanced classifier that identifies additional classes of noise such as machine gun fire, vehicles, and thunder. Additional signal metrics were explored given the increased complexity of the classifier. By broadening the types of noise the system can accurately classify and increasing the number of metrics, a new system was developed with increased blast noise accuracy, decreased number of missed events, and significantly fewer false positives
X-ray CT analysis after blast of composite sandwich panels
Four composite sandwich panels with either single density or graded density foam cores and different face-sheet materials were subjected to full-scale underwater blast testing. The panels were subjected to 1kg PE4 charge at a stand-off distance of 1 m. The panel with graded density core and carbon fiber face-sheets had the lowest deflection. Post-blast damage assessment was carried out using X-ray CT scanning. The damage assessment revealed that there is a trade-off between reduced panel deflection and panel damage. This research has been performed as part of a program sponsored by the Office of Naval Research (ONR)
Revised Annotations, Sex-Biased Expression, and Lineage-Specific Genes in the Drosophila melanogaster group
Here, we provide revised gene models for D. ananassae, D. yakuba, and D.
simulans, which include UTRs and empirically verified intron-exon boundaries,
as well as ortholog groups identified using a fuzzy reciprocal-best-hit blast
comparison. Using these revised annotations, we perform differential expression
testing using the cufflinks suite to provide a broad overview of differential
expression between reproductive tissues and the carcass. We identify thousands
of genes that are differentially expressed across tissues in D. yakuba and D.
simulans, with roughly 60% agreement in expression patterns of orthologs in D.
yakuba and D. simulans. We identify several cases of putative polycistronic
transcripts, pointing to a combination of transcriptional read-through in the
genome as well as putative gene fusion and fission events across taxa. We
furthermore identify hundreds of lineage specific genes in each species with no
blast hits among transcripts of any other Drosophila species, which are
candidates for neofunctionalized proteins and a potential source of genetic
novelty.Comment: Revised manuscript, also available online preprint at G3: Genes,
Genomes, Genetics. Gene models, ortholog calls, and tissue specific
expression results are available at http://github.com/ThorntonLab/GFF or the
UCSC browser on the Thornton Lab public track hub at http://genome.ucsc.ed
Ketahanan Galur-Galur Padi Pup1 Terhadap Penyakit Blas
Blast is one of major disease on the upland rice in Indonesia. Upland rice lines derived from Kasalath and NILC443 crosses, containing Pup1 gen locus had been developed and evaluated for P fertilizer efficiency. Those lines would be evaluated for blast resistance, due to the fact that Pup1 locus contains genes involved in plant defend mechanism to disease, including blast disease. The BC2F5 plants derived from six crosses (DK, DN, SK, SN, BK, BN) were used in this research. Responses to blast disease in the green house were evaluated at ICABIOGRAD Bogor from March to April 2011, using combination of three blast races (race 173, 033, and 133). The response to blast disease in the field was evaluated at Taman Bogo Research Station, Lampung, and at farmer\u27s field in Cikeusal Village, Banten, from January to April 2011. Molecular analysis to trace Pup1 gene locus was conducted at the Molecular Biology Laboratory, using specific primer K20-2, from January to August 2013. Based on the molecular analysis all Pup1 lines showed homozygoes alleles, except the heterozygoes alleles on SK7, SK8, SK15, SK16, BN8 line, which were then not included in the next planting. The responses to blast at greenhouse among lines varied, but the Pup1 lines were mostly at level of moderate resistan (AT). Based on the result from the field experiment, most of Pup1 lines were resistance, however the susceptible check plant (Kencana Bali) did not show blast fungus infection. Differences of the result might be due to the blast testing at the green house which was more favorable for blast fungal growth. The effect of Pup1 gene locus showed clearly on resistance of plants obtained from Situ Bagendit cross, where Situ Bagendit was susceptible and does not contain the Pup1 locus. Additional of Pup1 locus in Situ Bagendit genome had increased the degree of resistant to blast
Sandwich Panel Cores for Blast Applications: Materials and Graded Density
Sandwich composites are of interest in marine applications due to their high strength-to-weight ratio and tailorable mechanical properties, but their resistance to air blast loading is not well understood. Full-scale 100 kg TNT equivalent air blast testing at a 15 m stand-off distance was performed on glass-fibre reinforced polymer (GFRP) sandwich panels with polyvinyl chloride (PVC); polymethacrylimid (PMI); and styrene acrylonitrile (SAN) foam cores, all possessing the same thickness and density. Further testing was performed to assess the blast resistance of a sandwich panel containing a stepwise graded density SAN foam core, increasing in density away from the blast facing side. Finally a sandwich panel containing compliant polypropylene (PP) fibres within the GFRP front face-sheet, was subjected to blast loading with the intention of preventing front face-sheet cracking during blast. Measurements of the sandwich panel responses were made using high-speed digital image correlation (DIC), and post-blast damage was assessed by sectioning the sandwich panels and mapping the damage observed. It was concluded that all cores are effective in improving blast tolerance and that the SAN core was the most blast tolerant out of the three foam polymer types, with the DIC results showing a lower deflection measured during blast, and post-blast visual inspections showing less damage suffered. By grading the density of the core it was found that through thickness crack propagation was mitigated, as well as damage in the higher density foam layers, thus resulting in a smoother back face-sheet deflection profile. By incorporating compliant PP fibres into the front face-sheet, cracking was prevented in the GFRP, despite damage being present in the core and the interfaces between the core and face-sheets
Instrumental performance and results from testing of the BLAST-TNG receiver, submillimeter optics, and MKID arrays
Polarized thermal emission from interstellar dust grains can be used to map
magnetic fields in star forming molecular clouds and the diffuse interstellar
medium (ISM). The Balloon-borne Large Aperture Submillimeter Telescope for
Polarimetry (BLASTPol) flew from Antarctica in 2010 and 2012 and produced
degree-scale polarization maps of several nearby molecular clouds with
arcminute resolution. The success of BLASTPol has motivated a next-generation
instrument, BLAST-TNG, which will use more than 3000 linear polarization
sensitive microwave kinetic inductance detectors (MKIDs) combined with a 2.5m
diameter carbon fiber primary mirror to make diffraction-limited observations
at 250, 350, and 500 m. With 16 times the mapping speed of BLASTPol,
sub-arcminute resolution, and a longer flight time, BLAST-TNG will be able to
examine nearby molecular clouds and the diffuse galactic dust polarization
spectrum in unprecedented detail. The 250 m detector array has been
integrated into the new cryogenic receiver, and is undergoing testing to
establish the optical and polarization characteristics of the instrument.
BLAST-TNG will demonstrate the effectiveness of kilo-pixel MKID arrays for
applications in submillimeter astronomy. BLAST-TNG is scheduled to fly from
Antarctica in December 2017 for 28 days and will be the first balloon-borne
telescope to offer a quarter of the flight for "shared risk" observing by the
community.Comment: Presented at SPIE Millimeter, Submillimeter, and Far-Infrared
Detectors and Instrumentation for Astronomy VIII, June 29th, 201
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