104 research outputs found
Dense nonaqueous phase liquid (DNAPL) source zone characterization: Influence of hydraulic property correlation on predictions of DNAPL infiltration and entrapment
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95335/1/wrcr9623.pd
A Deep VLA survey at 20cm of the ISO ELAIS survey regions
We have used the Very Large Array(VLA) in C configuration to carry out a
sensitive 20cm radio survey of regions of sky that have been surveyed in the
Far Infra-Red over the wavelength range 5-200 microns with ISO as part of the
European Large Area ISO Survey(ELAIS). As usual in surveys based on a
relatively small number of overlapping VLA pointings the flux limit varies over
the area surveyed. The survey has a flux limit that varies from a 5
limit of 0.135mJy over an area of 0.12deg to a 5 limit of 1.15mJy
or better over the whole region covered of 4.22 deg. In this paper we
present the radio catalogue of 867 sources. These regions of sky have
previously been surveyed to shallow flux limits at 20cm with the VLA as part of
the VLA D configuration NVSS(FWHM=45 arcsec) and VLA B configuration
FIRST(FWHM=5 arcsec) surveys. We have carried out a a detailed comparison of
the reliability of our own survey and these two independent surveys in order to
assess the reliability and completeness of each survey.Comment: 19 pages, 24 figures, submitted to MNRAS, also available in
http://www.ast.cam.ac.uk/~ciliegi/elais/paper
Comparison of two‐dimensional and three‐dimensional simulations of dense nonaqueous phase liquids (DNAPLs): Migration and entrapment in a nonuniform permeability field
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95015/1/wrcr10030.pd
The European Large Area ISO Survey II: mid-infrared extragalactic source counts
We present preliminary source counts at 6.7um and 15um from the Preliminary
Analysis of the European Large Area ISO survey, with limiting flux densities of
\~2mJy at 15um & ~1mJy at 6.7um. We separate the stellar contribution from the
extragalactic using identifications with APM sources made with the likelihood
ratio technique. We quantify the completeness & reliability of our source
extraction using (a) repeated observations over small areas, (b) cross-IDs with
stars of known spectral type, (c) detections of the PSF wings around bright
sources, (d) comparison with independent algorithms. Flux calibration at 15um
was performed using stellar IDs; the calibration does not agree with the
pre-flight estimates, probably due to effects of detector hysteresis and
photometric aperture correction. The 6.7um extragalactic counts are broadly
reproduced in the Pearson & Rowan-Robinson model, but the Franceschini et al.
(1997) model underpredicts the observed source density by ~0.5-1 dex, though
the photometry at 6.7um is still preliminary. At 15um the extragalactic counts
are in excellent agreement with the predictions of the Pearson & Rowan-Robinson
(1996), Franceschini et al. (1994), Guiderdoni et al. (1997) and the evolving
models of Xu et al. (1998), over 7 orders of magnitude in 15um flux density.
The counts agree with other estimates from the ISOCAM instrument at overlapping
flux densities (Elbaz et al. 1999), provided a consistent flux calibration is
used. Luminosity evolution at a rate of (1+z)^3, incorporating mid-IR spectral
features, provides a better fit to the 15um differential counts than (1+z)^4
density evolution. No-evolution models are excluded, and implying that below
around 10mJy at 15um the source counts become dominated by an evolving
cosmological population of dust-shrouded starbursts and/or active galaxies.Comment: MNRAS in press. 14 pages, uses BoxedEPS (included). For more
information on the ELAIS project see http://athena.ph.ic.ac.uk
Brownfield Action: Dissemination of a SENCER Model Curriculum and the Creation of a Collaborative STEM Education Network
Brownfield Action (BA) is a web-based environmental site assessment (ESA) simulation in which students form geotechnical consulting companies and work together to solve problems in environmental forensics. Developed at Barnard College with the Columbia Center for New Media Teaching and Learning, BA has been disseminated to ten colleges, universities, and high schools, resulting in a collaborative network of educators. The experiences of current users are presented describing how they have incorporated the BA curriculum into their courses, as well as how BA affected teaching and learning. The experiences demonstrate that BA can be used in whole or in part, is applicable to a wide range of student capabilities and has been successfully adapted to a variety of learning goals, from introducing non-science-literate students to basic concepts of environmental science and civic issues of environmental contamination to providing advanced training in ESA and modeling groundwater contamination to future environmental professionals
The European Large Area ISO Survey: ELAIS
The European Large Area ISO Survey (ELAIS) has surveyed 12 square degrees of
the sky at 15 and 90 microns, and subsets of this area at 6.75 and 175 microns,
using the Infrared Space Observatory (ISO). This project was the largest single
open time programme executed by ISO, taking 375 hours of data. A preliminary
catalogue of more than 1000 galaxies has been produced. In this talk we
describe the goals of the project, describe the follow-up programmes that are
in progress, and present some first scientific results including a provisional
number count analysis at 15 and 90 microns.Comment: 5 pages, 3 figures, 4 tables, to appear in 'The universe as seen by
ISO', eds P.Cox and M.F.Kessler, 1998, UNESCO, Paris, ESA Special
Publications Series (SP-427
Geospatial relationships of air pollution and acute asthma events across the Detroit–Windsor international border: Study design and preliminary results
The Geospatial Determinants of Health Outcomes Consortium (GeoDHOC) study investigated ambient air quality across the international border between Detroit, Michigan, USA and Windsor, Ontario, Canada and its association with acute asthma events in 5- to 89-year-old residents of these cities. NO2, SO2, and volatile organic compounds (VOCs) were measured at 100 sites, and particulate matter (PM) and polycyclic aromatic hydrocarbons (PAHs) at 50 sites during two 2-week sampling periods in 2008 and 2009. Acute asthma event rates across neighborhoods in each city were calculated using emergency room visits and hospitalizations and standardized to the overall age and gender distribution of the population in the two cities combined. Results demonstrate that intra-urban air quality variations are related to adverse respiratory events in both cities. Annual 2008 asthma rates exhibited statistically significant positive correlations with total VOCs and total benzene, toluene, ethylbenzene and xylene (BTEX) at 5-digit zip code scale spatial resolution in Detroit. In Windsor, NO2, VOCs, and PM10 concentrations correlated positively with 2008 asthma rates at a similar 3-digit postal forward sortation area scale. The study is limited by its coarse temporal resolution (comparing relatively short term air quality measurements to annual asthma health data) and interpretation of findings is complicated by contrasts in population demographics and health-care delivery systems in Detroit and Windsor
The ISOPHOT-MAMBO survey of 3CR radio sources: Further evidence for the unified schemes
We present the complete set of ISOPHOT observations of 3CR radio galaxies and
quasars, which are contained in the ISO Data Archive, providing 75 mid- and
far-infrared spectral energy distributions (SEDs) between 5 and 200 micron. For
28 sources they are supplemented with MAMBO 1.2 mm observations and for 15
sources with new submillimetre data from the SCUBA archive.
We check the orientation-dependent unified scheme, in which the powerful FR2
narrow line galaxies are quasars viewed at high inclination, so that their
nuclei are hidden behind a dust torus intercepting the optical-ultraviolet AGN
radiation and reemitting it in the infrared. We find that (1) both the quasars
and the galaxies show a high mid- to far-infrared luminosity ratio typical for
powerful AGNs and (2) -- when matched in 178 MHz luminosity -- both show the
same ratio of isotropic far-infrared to isotropic 178 MHz lobe power.
Therefore, from our large sample investigated here we find strong evidence for
the orientation-dependent unification of the powerful FR2 galaxies with the
quasars.Comment: 16 pages, 7 figures, 3 tables, accepted by Astronomy & Astrophysic
Dust emission from 3C radio galaxies and quasars: New ISO observations favour the unified scheme
In order to test the unified scheme for luminous radio galaxies and quasars
we observed 10 galaxy/quasar pairs from the 3CR catalogue with ISOPHOT at
infrared wavelengths between 5 and 180 micron. Each pair was selected such that
both the 178 MHz luminosity and the redshift match as close as possible between
the radio galaxy and the quasar in order to minimize effects of cosmic
evolution. 13 of the 20 sources were detected in at least one waveband. 12
sources show clear evidence of a thermal bump at FIR wavelength, while in the
remaining 7 sources the upper limits are still compatible with the presence of
luminous dust emission. In agreement with the predictions of the unified
scheme, the quasars and galaxies in our sample cannot be distinguished by their
observed mid- and far-infrared properties. This is in contrast to the IRAS
results which indicated that radio galaxies radiate significantly less mid- to
far-infrared emission than quasars. However, the IRAS samples are dominated by
low-redshift sources (z < 0.5), while our sample contains several of the most
luminous radio galaxies at redshift z ~ 1. The latter have already been
suspected to contain a hidden quasar for other reasons, e.g. an extended
emission line region aligned with the radio axis. From the ratio between FIR
luminosity emitted by dust and the radio power at 178 MHz, we conclude that the
radio galaxy/quasar unification might be perfectly valid for the most luminous
3C sources at high redshift (z > 0.8). At lower redshifts (z < 0.5), however,
some of the FRII radio galaxies contain active nuclei which emit less
UV-optical continuum than the quasars of similar radio power. (abrigded)Comment: 10 pages, 6 figures, Late
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