Fire extinguishant materials

Fire extinguishant composition comprising a mixture of a finely divided aluminum compound and alkali metal, stannous or plumbous halide is provided. Aluminum compound may be aluminum hydroxide, alumina or boehmite but preferably it is an alkali metal dawsonite. The metal halide may be an alkali metal, e.g. potassium iodide, bromide or chloride or stannous or plumbous iodide, bromide or chloride. Potassium iodide is preferred

BATSE Soft Gamma-Ray Observations of GROJ0422+32

We report results of a comprehensive study of the soft gamma-ray (30 keV to 1.7 MeV) emission of GROJ0422+32 during its first known outburst in 1992. These results were derived from the BATSE earth-occultation database with the JPL data analysis package, EBOP (Enhanced BATSE Occultation Package). Results presented here focus primarily on the long-term temporal and spectral variability of the source emission associated with the outburst. The light curves with 1-day resolution in six broad energy-bands show the high-energy flux (>200 keV) led the low-energy flux (<200 keV) by ~5 days in reaching the primary peak, but lagged the latter by ~7 days in starting the declining phase. We confirm the "secondary maximum" of the low-energy (<200 keV) flux at TJD 8970-8981, ~120 days after the first maximum. Our data show that the "secondary maximum" was also prominent in the 200-300 keV band, but became less pronounced at higher energies. During this 200-day period, the spectrum evolved from a power-law with photon index of 1.75 on TJD 8839, to a shape that can be described by a Comptonized model or an exponential power law below 300 keV, with a variable power-law tail above 300 keV. The spectrum remained roughly in this two-component shape until ~9 November (TJD 8935) and then returned to the initial power-law shape with an index of ~2 until the end of the period. The correlation of the two spectral shapes with the high and low luminosities of the soft gamma-ray emission is strongly reminiscent of that seen in Cygnus X-1. We interpret these results in terms of the Advection Dominated Accretion Flow (ADAF) model with possibly a "jet-like" region that persistently produced the non-thermal power-law gamma rays observed throughout the event.Comment: 40 pages total, including 10 figures and 2 table

Modified dispersion relations and black hole physics

A modified formulation of energy-momentum relation is proposed in the context of doubly special relativity. We investigate its impact on black hole physics. It turns out that such modification will give corrections to both the temperature and the entropy of black holes. In particular this modified dispersion relation also changes the picture of Hawking radiation greatly when the size of black holes approaching the Planck scale. It can prevent black holes from total evaporation, as a result providing a plausible mechanism to treat the remnant of black holes as a candidate for dark matter.Comment: 4 pages, Revtex. Final version to appear in PR

Reply to Comment by D. Spemann et al [EPL 98 (2012) 57006, arXiv:1204.2992]

This article is a reply to the Comment by D. Spemann et al (arXiv:1204.2992) in response to our paper 'Revealing common artifacts due to ferromagnetic inclusions in highly oriented pyrolytic graphite' (EPL, 97 (2012) 47001).Comment: Reply to arXiv:1204.2992 Comment by D. Spemann et al re arXiv:1201.6374 by Sepioni et a

Optimization of aircraft seat cushion fire blocking layers

This report describes work completed by the National Aeronautics and Space Administration - for the Federal Aviation Administration Technical Center. The purpose of this work was to examine the potential of fire blocking mechanisms for aircraft seat cushions in order to provide an optimized seat configuration with adequate fire protection and minimum weight. Aluminized thermally stable fabrics were found to provide adequate fire protection when used in conjunction with urethane foams, while maintaining minimum weight and cost penalty

Gamma-Ray Spectra & Variability of the Crab Nebula Emission Observed by BATSE

We report ~ 600 days of BATSE earth-occultation observations of the total gamma-ray (30 keV to 1.7 MeV) emission from the Crab nebula, between 1991 May 24 (TJD 8400) and 1994 October 2 (TJD 9627). Lightcurves from 35-100, 100-200, 200-300, 300-400, 400-700, and 700-1000 keV, show that positive fluxes were detected by BATSE in each of these six energy bands at significances of approximately 31, 20, 9.2, 4.5, 2.6, and 1.3 sigma respectively per day. We also observed significant flux and spectral variations in the 35-300 keV energy region, with time scales of days to weeks. The spectra below 300 keV, averaged over typical CGRO viewing periods of 6-13 days, can be well described by a broken power law with average indices of ~ 2.1 and ~ 2.4 varying around a spectral break at ~ 100 keV. Above 300 keV, the long-term averaged spectra, averaged over three 400 d periods (TJD 8400-8800, 8800-9200, and 9200-9628, respectively) are well represented by the same power law with index of ~ 2.34 up to ~ 670 keV, plus a hard spectral component extending from ~ 670 keV to ~ 1.7 MeV, with a spectral index of ~ 1.75. The latter component could be related to a complex structure observed by COMPTEL in the 0.7-3 MeV range. Above 3 MeV, the extrapolation of the power-law continuum determined by the low-energy BATSE spectrum is consistent with fluxes measured by COMPTEL in the 3-25 MeV range, and by EGRET from 30-50 MeV. We interpret these results as synchrotron emission produced by the interaction of particles ejected from the pulsar with the field in different dynamical regions of the nebula system, as observed recently by HST, XMM-Newton, and Chandra.Comment: To be published in the November 20, 2003, Vol 598 issue of the Astrophysical Journa

Fate of the Peak Effect in a Type-II Superconductor: Multicriticality in the Bragg-Glass Transition

We have used small-angle-neutron-scattering (SANS) and ac magnetic susceptibility to investigate the global magnetic field H vs temperature T phase diagram of a single crystal Nb in which a first-order transition of Bragg-glass melting (disordering), a peak effect, and surface superconductivity are all observable. It was found that the disappearance of the peak effect is directly related to a multicritical behavior in the Bragg-glass transition. Four characteristic phase boundary lines have been identified on the H-T plane: a first-order line at high fields, a mean-field-like continuous transition line at low fields, and two continuous transition line associated with the onset of surface and bulk superconductivity. All four lines are found to meet at a multicritical point.Comment: 4 figure

Development and testing of dry chemicals in advanced extinguishing systems for jet engine nacelle fires

The effectiveness of dry chemical in extinguishing and delaying reignition of fires resulting from hydrocarbon fuel leaking onto heated surfaces such as can occur in jet engine nacelles is studied. The commercial fire extinguishant dry chemical tried are sodium and potassium bicarbonate, carbonate, chloride, carbamate (Monnex), metal halogen, and metal hydroxycarbonate compounds. Synthetic and preparative procedures for new materials developed, a new concept of fire control by dry chemical agents, descriptions of experiment assemblages to test dry chemical fire extinguishant efficiencies in controlling fuel fires initiated by hot surfaces, comparative testing data for more than 25 chemical systems in a 'static' assemblage with no air flow across the heated surface, and similar comparative data for more than ten compounds in a dynamic system with air flows up to 350 ft/sec are presented

Gamma-ray burst variability above 4 MeV

The relationship between the hard X-ray and gamma ray emissions during four bursts using the anti-coincidence shields of the High Energy Astronomy Observatory 3 (HEAO 3) Gamma Ray Spectrometer is explored. Recent observations of gamma ray bursts by the Solar Maximum Mission Gamma Ray Spectrometer (GRS) have shown that high energy emission above 1 MeV is a common and energetically important feature (Matz et al. 1985). Time histories of four gamma ray bursts in 3 energy bands ( keV, around 511 keV, and 4 MeV) with 10.24 a resolution show that the 4 MeV flux is only weakly coupled to the spectrum below approximately 600 keV