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281.
S. B. Carpenter J. M. Leavitt Fred W. Thomas John A. Frizzola Maynard E. Smith 《Journal of the Air & Waste Management Association (1995)》2013,63(7):458-465
This paper reports on the plume rise research project conducted by TVA under sponsorship of the U. S. Public Health Service. Plume rise data were collected at six coal-fired, steam-electric generating stations within the TVA system over a 2-year period. Unit ratings ranged from 173 to 704 Mw with stack heights varying from 250 to 600 ft. An instrumented helicopter and special photographic equipment were used to obtain 1580 separate plume observations and significant related meteorological parameters during stable, neutral, and slightly unstable conditions. The 1580 observations were resolved and consolidated into 133 composite observation periods covering 30 to 120 min. Meteorological parameters and other compiled input data were entered into four principal equations for calculation of plume rise, and calculated plume rise values were compared with observed values. Most equations overestimated plume rise in low wind speed. For moderately high wind speeds, the Carson and Moses and the Concawe equations gave best fit. 相似文献
282.
Fred H. Haynie John W. Spence 《Journal of the Air & Waste Management Association (1995)》2013,63(9):941-944
ABSTRACT The present study focuses on the elemental characterization of fine and coarse particles collected at a coastal site of southwestern Italy, in a suburban area of the Calabria region. A chemical tracer analysis was carried out to identify the major emission sources influencing on the atmospheric aerosol levels. Size-resolved particulate samples were collected during three 2-week seasonal sampling campaigns: autumn (19 October to 2 November 2003), winter (19 January to 2 February 2004) and spring (26 April to 10 May 2004). Ambient concentrations of selected elements (Fe, Mn, Mg, Ca, V, Cu, Cr, Ni, Zn, Pb, and Cd) associated to fine and coarse size fractions were determined using atomic absorption spectrometry (AAS). The enrichment factor method was applied, suggesting a prevailing anthropogenic component for all the detected elements, with Fe, Mg, Mn, and Ca as exceptions. Trajectory sector analysis was used in order to discriminate the influence of different air mass origins and paths. Long-range transport from both the continental Europe and the Saharan region proved to be the main influencing factors. African dust outbreaks, whose occurrence frequency was greater during the autumn and spring seasonal monitoring periods, gave rise to a total of eight exceedances of the European Commission (EC) PM10 daily limit value as well as an increase in values of the crustal-derived elements (Fe, Mg, and Ca). Long-range transport from the heavily industrialized area of Central/Eastern Europe contributed to the high levels of Zn, Cd, and Pb that were recorded during the winter sampling campaign. Seasonal trend and comparison with measurements previously performed across the Mediterranean basin were also presented and discussed.
IMPLICATIONS This paper, which investigates both natural and anthropogenic aerosol sources, contributes to the characterization of fine and coarse particles in a suburban area of the southern Italian region of Calabria whose air quality assessment is still being defined. The monitoring site involved in this study, located at the interface between continental Europe and the Mediterranean basin, offers an important platform to study the influence of seasonal meteorology and predominant circulation patterns on the aerosol concentration levels and their chemical composition. 相似文献
283.
Kenneth T. Knapp Fred D. Stump Silvestre B. Tejada 《Journal of the Air & Waste Management Association (1995)》2013,63(7):646-653
ABSTRACT The emissions from a fleet of 11 vehicles, including three from the State of Alaska, were tested at 75, 0, and -20 °F with base gasolines and E10 gasolines, that is, gasolines with 10% by volume ethanol added. The data for the changes in emissions for the test run at 75 °F are included, since most other studies on the effects of E10 gasoline on emissions were run at that temperature. The three Alaskan vehicles were also tested at 20 °F. The testing followed the Federal Test Procedure, and regulated emissions—CO, total hydrocarbons (THC), and nitrogen oxides (NOx)—CO2, speciated organics, and fuel economy were measured. A total of 490 FTP tests were run. The data obtained indicated that with most vehicles, at the temperatures tested, improvements in both CO and THC emissions were obtained with the use of E10 fuel. At the lowest temperature used, -20 °F, most vehicles had an increase in NO emissions with the use of E10 fuel. At the other temperatures, however, more vehicles showed a decrease in NOx emissions with the use of E10. With all vehicles at all temperatures tested, the emissions of acetaldehyde increased significantly when E10 fuel was used. The highest increase was about 8 to 1. Benzene, formaldehyde, and 1,3 butadiene showed both increases and decreases in the emissions when using E10 fuel. Unexpected results were obtained with the fuel economy, with about half of the tests showing an increase in fuel economy with the use of E10 fuel. 相似文献
284.
285.
We investigated whether fish assemblage structure in southern Appalachian streams differed with historical and contemporary
forest cover. We compared fish assemblages in 2nd–4th order streams draining watersheds that had increased forest cover between 1950 and 1993 (i.e., reforesting watersheds). We sampled fish in 50 m reaches during August 2001 and calculated catch-per-unit-effort (CPUE)
by taxonomic, distributional, trophic, reproductive, and thermal metrics. We assigned streams to reforestation categories
based on cluster analysis of years 1950 and 1993 near-stream forest cover. The relationship between forest cover and assemblage
structure was assessed using analysis of variance to identify differences in fish CPUE in five forest cover categories. Streams
contained 23 fish species representing six families, and taxa richness ranged from 1 to 13 at 30 stream sites. Streams with
relatively low near-stream forest cover were different from streams having moderate to high near-stream forest cover in 1950
and 1993. Fish assemblages in streams having the lowest amount of forest cover (53–75%) were characterized by higher cosmopolitan,
brood hider, detritivore/herbivore, intermediate habitat breadths, run-pool dweller, and warm water tolerant fish CPUE compared
to streams with higher riparian forest cover. Our results suggest that fish assemblage’s structural and functional diversity
and/or richness may be lower in streams having lower recent or past riparian forest cover compared to assemblages in streams
having a high degree of near-stream forest cover. 相似文献
286.
Most European goose populations have increased exponentially, and this has increasingly brought them into conflict with human activities. To manage this conflict, we used multi-criteria decision analysis to help set population targets for a super-abundant population of greylag geese (Anser anser). We relied on expert elicitation to assess the consequences of varying goose abundance on nine ecological, economic, and societal objectives. Representatives from national governments and from non-governmental organizations then weighted the objectives based on their perceived relative importance, and we used a consensus-convergence model to reach stakeholder agreement on the tradeoffs among objectives. The preferred population targets for two management units represent about a 20% reduction from current abundances, which from a management perspective would require considerable effort above and beyond current population-control measures. We believe that multi-criteria decision analysis can provide a systematic and transparent framework for building consensus among diverse stakeholders in a wide array of human-wildlife conflicts. 相似文献
287.
To better understand the role of herbivory and fire as potential disturbance processes in sagebrush communities, we examined
responses of a grazing ungulate, elk (Cervus elaphus), following prescribed burning of sagebrush (Artemisia
tridentata ssp. vaseyana) in south-central Montana (USA.) with concurrent monitoring of changes in plant production, nutritional quality, and community
diversity from 1989–1999. Burning transformed low-diversity, sagebrush-dominated communities into high-diversity, graminoid-forb
communities that persisted for 10 years without significant reestablishment of sagebrush. Elk increased use of burned sites
one year after burning, but elk use returned to pre-burn levels over the next two to nine years. Forage biomass and nutritional
quality declined after initial increases that coincided with increased elk use. Increases in elk use appeared to be influenced
by increases in combined graminoid and forb production and changes in structural vegetation characteristics that permitted
greater foraging efficiency. Declines in use were associated with loss of nutritional enhancement and declines in combined
graminoid and forb production. Managers may observe only short-term responses from grazing ungulates to prescribed fire in
sagebrush communities, but can expect longer-term increases in plant diversity and establishment of graminoid-forb communities. 相似文献
288.
Cadle SH Ayala A Black KN Fulper CR Graze RR Minassian F Murray HB Natarajan M Tennant CJ Lawson DR;Coordinating Research Council 《Journal of the Air & Waste Management Association (1995)》2007,57(2):139-145
The Coordinating Research Council held its 16th workshop in March 2006, with 83 presentations describing the most recent mobile source-related emissions research. In this paper, we summarize the presentations from researchers who are engaged in improving our understanding of the contribution of mobile sources to air quality. Participants in the workshop discussed evaluation of in-use emissions control programs, effects of fuels on emissions, emission models and emission inventories, results from gas- and particle-phase emissions studies from spark-ignition and diesel-powered vehicles, and efforts to improve our capabilities in performing on-board emissions measurements, as well as topics for future research. 相似文献
289.
Workplace resilience is a necessity for organizations and employees given it assists them in overcoming adversity and ultimately succeeding. However, organizational scholars have largely overlooked this construct. In this Incubator, we briefly summarize extant research on workplace resilience to highlight opportunities for theory building and advancement of empirical research. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
290.
Rachelle K. Gould Sarah C. Klain Nicole M. Ardoin Terre Satterfield Ulalia Woodside Neil Hannahs Gretchen C. Daily Kai M. Chan 《Conservation biology》2015,29(2):575-586
Stakeholders’ nonmaterial desires, needs, and values often critically influence the success of conservation projects. These considerations are challenging to articulate and characterize, resulting in their limited uptake in management and policy. We devised an interview protocol designed to enhance understanding of cultural ecosystem services (CES). The protocol begins with discussion of ecosystem‐related activities (e.g., recreation, hunting) and management and then addresses CES, prompting for values encompassing concepts identified in the Millennium Ecosystem Assessment (2005) and explored in other CES research. We piloted the protocol in Hawaii and British Columbia. In each location, we interviewed 30 individuals from diverse backgrounds. We analyzed results from the 2 locations to determine the effectiveness of the interview protocol in elucidating nonmaterial values. The qualitative and spatial components of the protocol helped characterize cultural, social, and ethical values associated with ecosystems in multiple ways. Maps and situational, or vignette‐like, questions helped respondents articulate difficult‐to‐discuss values. Open‐ended prompts allowed respondents to express a diversity of ecosystem‐related values and proved sufficiently flexible for interviewees to communicate values for which the protocol did not explicitly probe. Finally, the results suggest that certain values, those mentioned frequently throughout the interview, are particularly salient for particular populations. The protocol can provide efficient, contextual, and place‐based data on the importance of particular ecosystem attributes for human well‐being. Qualitative data are complementary to quantitative and spatial assessments in the comprehensive representation of people's values pertaining to ecosystems, and this protocol may assist in incorporating values frequently overlooked in decision making processes. 相似文献