5,557 research outputs found
Fiber-modified polyurethane foam for ballistic protection
Closed-cell, semirigid, fiber-loaded, self-extinguishing polyurethane foam material fills voids around fuel cells in aircraft. Material prevents leakage of fuel and spreading of fire in case of ballistic incendiary impact. It also protects fuel cell in case of exterior fire
Fire retardant foams developed to suppress fuel fires
Heat insulating polyurethane foam retards and suppresses fuel fires. Uniformly dispersed in the foam is a halogenated polymer capable of splitting off hydrogen halide upon heating and charring of the polyurethane
A small-scale test for fiber release from carbon composites
A test method was developed to determine relative fiber loss from pyrolyzed composites with different resins and fiber construction. Eleven composites consisting of woven and unwoven carbon fiber reinforcement and different resins were subjected to the burn and impact test device. The composites made with undirectional tape had higher fiber loss than those with woven fabric. Also, the fiber loss was inversely proportional to the char yield of the resin
Lithium abundances in nearby FGK dwarf and subgiant stars: internal destruction, Galactic chemical evolution, and exoplanets
We derive atmospheric parameters and lithium abundances for 671 stars and
include our measurements in a literature compilation of 1381 dwarf and subgiant
stars. First, a "lithium desert" in the effective temperature (Teff) versus
lithium abundance (A_Li) plane is observed such that no stars with Teff~6075 K
and A_Li~1.8 are found. We speculate that most of the stars on the low A_Li
side of the desert have experienced a short-lived period of severe surface
lithium destruction as main-sequence or subgiant stars. Next, we search for
differences in the lithium content of thin-disk and thick-disk stars, but we
find that internal processes have erased from the stellar photospheres their
possibly different histories of lithium enrichment. Nevertheless, we note that
the maximum lithium abundance of thick-disk stars is nearly constant from
[Fe/H]=-1.0 to -0.1, at a value that is similar to that measured in very
metal-poor halo stars (A_Li~2.2). Finally, differences in the lithium abundance
distribution of known planet-host stars relative to otherwise ordinary stars
appear when restricting the samples to narrow ranges of Teff or mass, but they
are fully explained by age and metallicity biases. We confirm the lack of a
connection between low lithium abundance and planets. However, we find that no
low A_Li planet-hosts are found in the desert Teff window. Provided that subtle
sample biases are not responsible for this observation, this suggests that the
presence of gas giant planets inhibit the mechanism responsible for the lithium
desert.Comment: ApJ, in press. Complete Tables 1 and 3 are available upon reques
Intumescent Coatings as Fire Retardants
Fire-retardant paint, when activated by the heat of fire, reacts to form a thick, low-density, polymeric coating or char layer. Water vapor and sulphur dioxide are released during the intumescent reaction
Large Magnetic Fields and Motions of OH Masers in W75 N
We report on a second epoch of VLBA observations of the 1665 and 1667 MHz OH
masers in the massive star-forming region W75 N. We find evidence to confirm
the existence of very strong (~40 mG) magnetic fields near source VLA 2. The
masers near VLA 2 are dynamically distinct and include a very bright spot
apparently moving at 50 km/s relative to those around VLA 1. This fast-moving
spot may be an example of a rare class of OH masers seen in outflows in
star-forming regions. Due to the variability of these masers and the rapidity
of their motions, tracking these motions will require multiple observations
over a significantly shorter time baseline than obtained here. Proper motions
of the masers near VLA 1 are more suggestive of streaming along magnetized
shocks rather than Keplerian rotation in a disk. The motions of the easternmost
cluster of masers in W75 N (B) may be tracing slow expansion around an unseen
exciting source.Comment: 7 pages including 4 figures (2 color) & 3 tables, to appear in Ap
Prevention and treatment of Swine Origin Influenza Virus (S-OIV) through the use of interferon: an in vivo and ex vivo study
Conference Theme: Translating Health Research into Policy and Practice for Health of the PopulationPoster Presentations - Emerging / Infectious Diseases: no. P115-Ab0101BACKGROUND: H1N1pdm infection emerged in 2009 as the first influenza pandemic of the 21st century and originated from a swine precursor virus. Though this new virus was associated with a low mortality compared with seasonal influenza and with another new emerging influenza virus (H5N1), the main concerns that exist were the mortality in younger patients (contrasting with a bias towards elderly patients with seasonal influenza) and the potential for this virus to re-assort with avian influenza viruses …published_or_final_versio
Automated longwall guidance and control vertical control subsystem, volume 2
Software documentation and a computer program listing for a horizon control of a longwall shearer are presented
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