Neutral hydrogen traces gravitational potentials. In the nearby universe, 21cm emission-line surveys show that the bulk of the HI resides in well-formed, optically-luminous galaxies. At high redshift, 21cm line absorption against background radio quasars occurs in gas-rich systems identified with the highest HI column densities – the " damped Lyman alpha " quasar absorption-line systems. High s...

In this study, the crashworthiness performance of a multi-cell column designed from B1500HS boron steel with three different hardness values and six regional hot-formed designs were compared in terms passenger safety. Energy absorption peak crushing force columns examined by impact simulations under oblique loading. “T25 heat-treated column” gave highest energy value, while "O25 column" lowest ...

The toxicity and corrosion potential of hydrogen sulfide in raw biogas underlines the need for biogas purification. Several techniques available for removal of hydrogen sulfide from biogas are out of the reach for common end users due to lack of knowledge, higher running costs, and insufficient operational skills. The present experimental study aims to propagate hydrogen sulfide removal techniq...

We study high-resolution spectra of the ‘overlapping-trough’ low-ionization broad absorption line (LoBAL) quasar SDSS 0300+0048. The Ca II, Mg II and Mg I column densities in SDSS 0300+0048 are the largest reported to date for any BAL outflow. The broad Ca II absorption in this object is mildly blended, but the blending can be disentangled to measure the Ca II column density, which is large eno...

We present an extended analysis of the high dispersion IUE spectra of SN 1993J in M 81, based on the improved data in the IUE final archive. Eight interstellar absorption components can be identified in the velocity range from −200 km s to +200 km s. Column densities are determined for Fe II, Mg I, Mg II, O I, S II, Si II, and Zn II. From the ion ratios, we estimate electron densities and tempe...

Title of Document: A STUDY OF OPTICAL, PHYSICAL AND CHEMICAL PROPERTIES OF AEROSOLS USING IN SITU MEASUREMENTS Zahra Chaudhry, Ph.D., 2009 Directed By: Professor Zhanqing Li, Department of Atmospheric and Oceanic Science Using a simple sampling apparatus, aerosol particles were collected on a polycarbonate substrate in various locations around the world. The focus of this study was Xianghe, Chi...

Cloud absorption, as inferred from the difference between net fluxes measured with stacked aircraft, is strongly affected by horizontal inhomogeneity. The simplest way to compensate for variability effects is to perform grand averages over flight legs (Valero et al. 1997). If the flight legs are long enough (several hundred km), averaging leads to a reliable estimate of column absorption (Raman...

The presence of large amount of “cold” (i.e. not much ionized, and substantially opaque in X–rays) matter around Active Galactic Nuclei is now a well established fact. For all Seyfert 2 galaxies observed in X–rays so far there is evidence for absorption in excess of the Galactic one. In a significant fraction of them, the column density of the absorbing matter exceeds 10 cm−2 (Maiolino et al. 1...

The 2007 National Research Council (NRC) Decadal Survey on Earth Science and Applications from Space recommended Active Sensing of CO(2) Emissions over Nights, Days, and Seasons (ASCENDS) as a midterm, Tier II, NASA space mission. ITT Exelis, formerly ITT Corp., and NASA Langley Research Center have been working together since 2004 to develop and demonstrate a prototype laser absorption spectro...

The cross-section of sky occupied by a particular neutral hydrogen column density (NHI) provides insight into the nature of Lyα absorption systems. We have measured this column density distribution at z=0 using 21-cm Hi emission from a blind survey. A subsample of HI Parkes All Sky Survey (HIPASS) galaxies have been imaged with the Australia Telescope Compact Array (ATCA). The contribution of l...