5,557 research outputs found

    Fiber-modified polyurethane foam for ballistic protection

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    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

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    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

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    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

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    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

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    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

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    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

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    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

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    Software documentation and a computer program listing for a horizon control of a longwall shearer are presented
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