689 research outputs found
FIRE PROTECTION AND LIFE SAFETY ANALYSIS OF A MODERN DISTRIBUTON FACILITY
Warehouse facilities are part of the backbone of American industry. The vast amounts of varying goods stored and distributed as part of American business has always driven the need for large, voluminous warehouses. And the increasing size of these facilities over the decades is very closely linked to the capabilities of and advances in fire protection knowledge and technology. Today’s modern distribution centers easily and often exceed one million square feet in area, and the heights are ever increasing. In the 1970’s and early 1980’s, most warehouse facilities were built to an approximate height of 30 feet; this, at the time, was the extent of the fire protection (i.e., sprinkler) knowledge and capabilities. Factory Mutual (now FM Global) developed the early suppression fast-response (“ESFR”) sprinkler in the 1980’s and buildings have been increasing in height ever since. Many applicable standards list multiple design criteria for various storage configurations in building with roof peaks up to 45 feet. Just recently this year, Viking released a nominal K-28 ESFR sprinkler that is listed to protect rack storage as a ceilingonly design option (i.e., without the need of costly in-rack fire sprinkler systems) in warehouses having a maximum roof height of 48 feet, and it is unlikely that this trend will stop. The industry will continue to research and develop safe design solutions that will allow more and more storage in a cost effective method, and as such, building and fire code will likewise evolve to accommodate. However, in the meantime, architects and engineers work to design these facilities within the parameters of governing building and fire codes, and when necessary, use performance-based design approaches when the building does not fit inside the box
Addressing Complications in the International Tax Regime Resulting from the Digitalization of the Economy
BUDGET PERSPECTIVES 2007
1. DISABILITY BENEFIT – CONTROLLED OR UNDER-CONTROLLED?
Brenda Gannon p. 3
2. CHILD POVERTY AND CHILD INCOME SUPPORTS: IRELAND IN COMPARATIVE PERSPECTIVE
Tim Callan, Kieran Coleman, Brian Nolan and John Walsh p. 23
3. STATE FINANCIAL SUPPORT FOR HORSE RACING IN IRELAND
Tony Fahey and Liam Delaney p. 3
Red star-forming and blue passive galaxies in clusters
We explore the relation between colour and specific star formation rate
(derived from optical spectra obtained by SDSS DR4) of over 6,000 galaxies
(M_r<=-20.5) in and around low redshift (z<0.12) clusters. Even though most red
galaxies have little or no ongoing star formation, and most blue galaxies are
currently forming stars, there are significant populations of red star-forming
(SF) and blue passive galaxies. This paper examines various properties of
galaxies belonging to the latter two categories. These properties include
morphological parameters, internal extinction, spectral features such as
EW(H_delta) and the 4000 ang break, and metallicity. Our analysis shows that
the blue passive galaxies have properties very similar to their SF
counterparts, except that their large range in EW(H_delta) indicates recent
truncation of star formation. The red SF galaxies fall into two broad
categories, one of them being massive galaxies in cluster cores dominated by an
old stellar population, but with evidence of current star formation in the
core. For the remaining red SF galaxies it is evident from various metallicity
measures and mean stellar ages, that their colours result from the predominance
of a metal-rich stellar population. The implication of the properties of these
SF galaxies on environmental studies, like that of the Butcher-Oemler effect,
is discussed.Comment: 13 pages, 11 figures, accepted for publication in MNRA
Very-high-energy gamma-ray emission from high-redshift blazars
We study the possible detection of and properties of very high-energy (VHE)
gamma-ray emission (in the energy band above 100 GeV) from high redshift
sources. We report on the detection of VHE gamma-ray flux from blazars with
redshifts z>0.5. We use the data of Fermi telescope in the energy band above
100 GeV and identify significant sources via cross-correlation of arrival
directions of individual VHE gamma-rays with the positions of known Fermi
sources. There are thirteen high-redshift sources detected in the VHE band by
Fermi/LAT telescope. The present statistics of the Fermi signal from these
sources is too low for a sensible study of the effects of suppression of the
VHE flux by pair production through interactions with Extragalactic Background
Light photons. We find that the detection of these sources with ground-based
gamma-ray telescopes would be challenging. However, several sources including
BL Lacs PKS 0426-380 at z=1.11, KUV 00311-1938 at z=0.61, B3 1307+433 at
z=0.69, PG 1246+586 at z=0.84, Ton 116 at z=1.065 as well as a flat-spectrum
radio quasar 4C +55.17 at z=0.89 should be detectable by HESS-II, MAGIC-II and
CTA. A high-statistics study of a much larger number of VHE gamma-ray sources
at cosmological distances would be possible with the proposed high-altitude
Cherenkov telescope [email protected]: 10 pages, 14 figure
Interacting Energy Components and Observational Data
In this note, we extend our previous work [Phys. Lett. B 644, 7 (2007),
astro-ph/0609597], and compare eleven interacting dark energy models with
different couplings to the observational data. However, none of these
models is better than the simplest CDM model. This implies that either
more exotic couplings are needed in the cosmological models with interaction
between dark energy and dust matter, or {\em there is no interaction at all}.
We consider that this result is disadvantageous to the interacting dark energy
models studied extensively in the literature.Comment: 15 pages, 5 figures, 3 tables, Latex2e; v2: references added; v3:
discussions added, Phys. Lett. B in press; v4: published versio
Open Issues on the Synthesis of Evolved Stellar Populations at Ultraviolet Wavelengths
In this paper we briefly review three topics that have motivated our (and
others') investigations in recent years within the context of evolutionary
population synthesis techniques. These are: The origin of the FUV up-turn in
elliptical galaxies, the age-metallicity degeneracy, and the study of the
mid-UV rest-frame spectra of distant red galaxies. We summarize some of our
results and present a very preliminary application of a UV grid of theoretical
spectra in the analysis of integrated properties of aged stellar populations.
At the end, we concisely suggest how these topics can be tackled once the World
Space Observatory enters into operation in the midst of this decade.Comment: 8 pages, 4 figures, accepted for publication in Astrophysics & Space
Science, UV Universe special issu
The characterization of the distant blazar GB6 J1239+0443 from flaring and low activity periods
In 2008 AGILE and Fermi detected gamma-ray flaring activity from the
unidentified EGRET source 3EG J1236+0457, recently associated with a flat
spectrum radio quasar GB6 J1239+0443 at z=1.762. The optical counterpart of the
gamma-ray source underwent a flux enhancement of a factor 15-30 in 6 years, and
of ~10 in six months. We interpret this flare-up in terms of a transition from
an accretion-disk dominated emission to a synchrotron-jet dominated one. We
analysed a Sloan Digital Sky Survey (SDSS) archival optical spectrum taken
during a period of low radio and optical activity of the source. We estimated
the mass of the central black hole using the width of the CIV emission line. In
our work, we have also investigated SDSS archival optical photometric data and
UV GALEX observations to estimate the thermal-disk emission contribution of GB6
J1239+0443. Our analysis of the gamma-ray data taken during the flaring
episodes indicates a flat gamma-ray spectrum, with an extension of up to 15
GeV, with no statistically-relevant sign of absorption from the broad line
region, suggesting that the blazar-zone is located beyond the broad line
region. This result is confirmed by the modeling of the broad-band spectral
energy distribution (well constrained by the available multiwavelength data) of
the flaring activity periods and by the accretion disk luminosity and black
hole mass estimated by us using archival data.Comment: 30 pages, 7 figures, 4 tables MNRAS Accepted on 2012 June 1
The Seventh Data Release of the Sloan Digital Sky Survey
This paper describes the Seventh Data Release of the Sloan Digital Sky Survey
(SDSS), marking the completion of the original goals of the SDSS and the end of
the phase known as SDSS-II. It includes 11663 deg^2 of imaging data, with most
of the roughly 2000 deg^2 increment over the previous data release lying in
regions of low Galactic latitude. The catalog contains five-band photometry for
357 million distinct objects. The survey also includes repeat photometry over
250 deg^2 along the Celestial Equator in the Southern Galactic Cap. A
coaddition of these data goes roughly two magnitudes fainter than the main
survey. The spectroscopy is now complete over a contiguous area of 7500 deg^2
in the Northern Galactic Cap, closing the gap that was present in previous data
releases. There are over 1.6 million spectra in total, including 930,000
galaxies, 120,000 quasars, and 460,000 stars. The data release includes
improved stellar photometry at low Galactic latitude. The astrometry has all
been recalibrated with the second version of the USNO CCD Astrograph Catalog
(UCAC-2), reducing the rms statistical errors at the bright end to 45
milli-arcseconds per coordinate. A systematic error in bright galaxy photometr
is less severe than previously reported for the majority of galaxies. Finally,
we describe a series of improvements to the spectroscopic reductions, including
better flat-fielding and improved wavelength calibration at the blue end,
better processing of objects with extremely strong narrow emission lines, and
an improved determination of stellar metallicities. (Abridged)Comment: 20 pages, 10 embedded figures. Accepted to ApJS after minor
correction
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