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11.
R. K. M. Jayanty B. W. Gay Jr. 《Journal of the Air & Waste Management Association (1995)》2013,63(12):1631-1637
A joint conference for the fifth straight year cosponsored by the Air & Waste Management Association’s EM-3, EM-4, and ITF-2 technical committees, and the Atmospheric Research and Exposure Assessment Laboratory (AREAL) of the U.S. Environmental Protection Agency, was held in Raleigh, North Carolina, May 1–4, 1990. The technical program consisted of 187 presentations, held in 20 technical sessions, on recent advances in the measurement and monitoring of toxic and related pollutants found in ambient and source atmospheres. Covering a wide range of measurement topics and supported by 66 exhibitors of instrumentation and consulting services, the symposium was attended by more than 850 professionals from the United States and other countries. This overview highlights a selection of the technical presentations. A synopsis of the keynote address to the symposium is also included. 相似文献
12.
R. K. M. Jayanty B. W. Gay Jr. 《Journal of the Air & Waste Management Association (1995)》2013,63(11):1432-1439
A joint conference cosponsored for the sixth year by the Atmospheric Research and Exposure Assessment Laboratory (AREAL) of the U.S. Environmental Protection Agency and the Air & Waste Management Association was held in Durham, North Carolina, May 6–10, 1991. The technical program consisted of 220 presentations, held in 25 technical sessions, on recent advances in ambient and source atmospheres. Covering a wide range of measurement topics and supported by 78 exhibitors of instrumentation and consulting services, the symposium was attended by almost a thousand professionals from the United States and other countries. This overview highlights a selection of the technical presentations, and includes a synopsis of the keynote address. 相似文献
13.
Kamal El Kadi Abderrezzak André Paquier Bernard Gay 《Environmental Fluid Mechanics》2008,8(2):169-198
This paper reports a numerical study on dam-break waves over movable beds. A one-dimensional (1-D) model is built upon the
Saint-Venant equations for shallow water waves, the Exner equation of sediment mass conservation and a spatial lag equation
for non-equilibrium sediment transport. The set of governing equations is solved using an explicit finite difference scheme.
The model is tested in various idealized experimental cases, with fairly good agreement between the numerical predictions
and measurements. Discrepancies are observed at the earlier stage of the dam-break wave and around the dam location due to
no vertical velocity component being taken into account. Sensitivity tests confirm that the friction coefficient is an important
parameter for the evaluation of sediment transport processes operating during a dam-break wave. The influence of the non-equilibrium
adaptation length (or the lag distance) is negligible on the wavefront celerity and weak on the free surface and bed profiles,
which indicates that one may ignore the spatial lag effect in dam-break wave studies. Finally, the simulation of the Lake
Ha!Ha! dyke-break flood event shows that the model can provide relevant results if a convenient formula for computing the
sediment transport capacity and an appropriate median grain diameter of riverbed material are selected. 相似文献
14.
Eric P. S. Baumer Francesca Polletta Nicole Pierski Geri K. Gay 《Environmental Communication: A Journal of Nature and Culture》2017,11(3):289-310
This paper explores a technique for mitigating framing effects in perceptions of global climate change. People's opinions on issues ranging from same sex marriage and the environment to free speech and health care have been shown to be influenced by the way in which the issue is presented: the metaphors, images, and catchphrases that communicate implicit normative messages about the issue. The work described here synthesizes insights from experimental research on moderators of framing effects and sociological research on frame reflection. Based on this synthesis, this paper describes a test of a simple highlighting technique for focusing respondents' attention on the framing operating in political materials. Results suggest that this intervention not only can reduce the opinion-shaping impact of frames but may also reduce ideological polarization. Implications include a better understanding of the mechanisms by which frames operate, techniques for making frame reflection possible among political non-elites, and recommendations for strengthening environmental groups' public communication strategies. 相似文献
15.
Jeffrey M. Levengood David J. Soucek Christopher A. Taylor David A. Gay 《Environmental monitoring and assessment》2013,185(8):6485-6494
Documenting long-term trends in mercury deposition and/or accumulation is important in setting regulatory benchmarks, modeling contaminant transfer and flux, measuring success of environmental controls, and even assigning responsibility for pollution. We conducted a study to compare mercury concentrations in small fishes from “high-mercury” and “low-mercury” regions of Illinois, as well as to examine historic patterns of mercury availability using preserved fishes. Mercury concentrations were greater in four species of small fishes collected from a stream in a “high-mercury” region than in those same taxa collected from a stream in a “low-mercury” area in Illinois. Mercury concentrations in blackstripe topminnows (Fundulus notatus) declined dramatically between 1900 and 1961/2006 in the “high-mercury” stream, presumably due reductions in mercury releases from local and regional sources. Preserved fish had an apparent increase in mercury concentrations for up to 12 months, which is consistent with changes in mass and loss of proteins observed in other studies, and we recommend that recent samples be preserved for at least 12 months before comparison with older fluid-preserved material. Based on our results, further studies of mercury in small fishes in Illinois streams appear warranted. 相似文献
16.
Kevin P. Robinson Michael J. Tetley E. Gay Mitchelson-Jacob 《Journal of Coastal Conservation》2009,13(1):39-48
The coastal waters of the Moray Firth in northeast Scotland (57o41’N 2o40’W) provide rich, inshore feeding grounds for minke
whales (Balaenoptera acutorostrata) during the summer and autumnal months. In order to better understand the habitat selection, movements and feeding ecology
of the animals utilising this North Sea region, distribution data from the southern coastline of the outer Moray Firth were
subsequently examined with respect to the marine physiography of the area, specifically the environmental variables water
depth, slope, aspect and sediment-type. A total of 305 minke whale encounters – collected from dedicated boat surveys conducted
between May and October 2001 to 2006 inclusive – were used in the construction of a Geographic Information System (GIS) for
the 860 square-km study site. The subsequent analysis revealed a strong spatial preference by whales in this location for
water depths between 20 and 50 metres (mean 46.9 m, SD = 30.9), steep slopes (mean 75.7 degrees, SD = 8.9), a northerly-facing
aspect and sandy-gravel sediment type. Kruskal-Wallis tests for variance confirmed that the distribution of B. acutorostrata was significantly different across each of these physiographic features examined (P < 0.05). In particular, water depth and sediment type were shown to be highly correlated with the frequency of whales observed
(Spearman’s Rank Correlation P < 0.05 for depth and sediment respectively). From these results, we conclude that sea bottom characteristics may be used to
predict the fine-scale distribution of minke whales on their feeding grounds; the physiographic features identified providing
valuable proxies for inferring prey distributions in the absence of fisheries data. However, an appreciation of both abiotic
and biotic factors (using a combination of GIS and remote sensing outputs) is clearly desirable for ecosystem-based management
approaches for the coastal conservation of these whales. The application of GIS capacities to ecological studies based largely
on field data of these marine mammals is highly recommended in the present study to cetologists, environmental modellers and
conservation managers alike. 相似文献
17.
18.
Sven A. Nimmermark David R. Schmidt Susan W. Gay 《Journal of the Air & Waste Management Association (1995)》2013,63(9):1306-1314
Abstract A comparison between predicted and observed odor intensities at 20 neighborhood residences in the vicinity of seven various livestock farms in five different Minnesota counties was made to evaluate the Odor From Feedlots, Setback Estimation Tool (OFFSET) developed by the University of Minnesota. Observations by neighborhood monitors suggest that the OFFSET-predicted separation distances for annoyance-free frequencies of 99, 98, and 97% are large enough. The observations additionally indicate that predicted distances to obtain 94 and 91% annoyance-free frequencies may be large enough for some farms, but for other farms, greater distances may be needed. For two farms in the study, no significant difference between all of the observed and predicted intensities could be found. At four sites, a significant difference was found, and at three of these the difference was considerable. Odor emission rates used in the OFFSET model seem to describe the average emission fairly well for many odor sources, but improvement may be needed for some types of sources. Possible reasons for observations of annoying odor when not predicted include fluctuations in the odor emissions, wind speed fluctuations, topographic variation between sites, sensitivity differences by neighborhood monitors, and background emissions from other sources. 相似文献
19.
C.R. Forero P. Gayán F. García-Labiano L.F. de Diego A. Abad J. Adánez 《International Journal of Greenhouse Gas Control》2010,4(5):762-770
Chemical-Looping Combustion (CLC) is an emerging technology for CO2 capture because separation of this gas from the other flue gas components is inherent to the process and thus no energy is expended for the separation. Natural or refinery gas can be used as gaseous fuels and they may contain different amounts of sulphur compounds, such as H2S and COS. This paper presents the combustion results obtained with a Cu-based oxygen carrier using mixtures of CH4 and H2S as fuel. The influence of H2S concentration on the gas product distribution and combustion efficiency, sulphur splitting between the fuel reactor (FR) and the air reactor (AR), oxygen carrier deactivation and material agglomeration was investigated in a continuous CLC plant (500 Wth). The oxygen carrier to fuel ratio, ?, was the main operating parameter affecting the CLC system. Complete fuel combustion were reached at 1073 K working at ? values ≥1.5. The presence of H2S did not produce a decrease in the combustion efficiency even when working with a fuel containing 1300 vppm H2S. At these conditions, the great majority of the sulphur fed into the system was released in the gas outlet of the FR as SO2, affecting to the quality of the CO2 produced. Formation of copper sulphide, Cu2S, and the subsequent reactivity loss was only detected working at low values of ? ≤ 1.5, although this fact did not produce any agglomeration problem in the fluidized beds. In addition, the oxygen carrier was fully regenerated in a H2S-free environment. It can be concluded that Cu-based oxygen carriers are adequate materials to be used in a CLC process using fuels containing H2S although quality of the CO2 produced is affected. 相似文献
20.
Passive ammonia monitoring in the United States: comparing three different sampling devices 总被引:1,自引:0,他引:1
Puchalski MA Sather ME Walker JT Lehmann CM Gay DA Mathew J Robarge WP 《Journal of environmental monitoring : JEM》2011,13(11):3156-3167
The need for ambient gaseous ammonia (NH(3)) measurements has increased in the last decade as reactive NH(3) concentrations and deposition fluxes show little change even with tightening standards on nitrogen oxides (NO(x)) emissions. Currently, there are several networks developing methods for adding NH(3) measurements in the U.S. Gaseous NH(3) measurements will provide scientists and policymakers data which can be used to estimate ecosystem inputs, validate air quality models including trends and regional variability, and evaluate changes to the environment based on additional emission reduction requirements and estimates of critical nitrogen load exceedances. The passive samplers described in this paper were deployed in duplicate or triplicate and collocated with annular denuders or continuous instruments to determine their accuracy. The samplers assessed included the Adapted Low-Cost Passive High Absorption (ALPHA), Radiello(?), and Ogawa passive samplers. The median relative percent differences (MRPD) between the reference method and passive samplers for the ALPHA, Radiello(?) and Ogawa were -2.4%, -37% and -44%, respectively. The precision between duplicate samplers for the ALPHA and Ogawa samplers, was 7% and 6%, respectively. Triplicate Radiello(?) precision was assessed using the coefficient of variation (CV). The CV for the Radiello(?) samplers was 10%. This article discusses the statistical results from these studies. 相似文献