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591.
Kyung Mi Lee Young Sup Lee 《Journal of the Air & Waste Management Association (1995)》2013,63(8):1139-1145
Abstract A bed-type filter composed of thin metal alloy fiber was closely examined with dust capturing in cold and hot runs. The investigation of an individual mechanism across the filter bed indicated that the aerated dust could be initially collected by depth filtration, and after a while, surface filtration dominated the overall dust collection. The present metal fiber bed was comparable to the conventional ceramic filters because of its good collection efficiency with low pressure drop. It also showed potential to be used as a prefilter in a diesel exhaust trapping system. 相似文献
592.
Cheong YW Yim GJ Ji SW Kang SS Skousen J 《Environmental monitoring and assessment》2012,184(1):503-513
The objective of this study was to assess the changes in mine water quality as an underground mine flooded from July 2005
to October 2008. The effect of air injection with a blower into the water was used to evaluate the potential to convert ferrous
to ferric iron and to provide in situ treatment and precipitation. Mine flooding averaged 31 cm/day with a linear shape until
November 2007, when it flattened out due to outflow. During flooding, mine water pH remained around 6, but Eh shifted from
200 to −150 mV. After the mine water level stabilized, contents of elements such as Fe and SO4 tended to decrease as time passed. Air was injected by diffusers (150 L/min/each) at three different depths of 2, 3, and
5 m below the water level in the shaft. Dissolved oxygen eventually increased to 4 or 5 mg/L depending on the depth of the
diffusers. Aeration caused conversion of ferrous iron to ferric iron and about 30 mg/l of iron was removed from the mine water.
Therefore, air injection shows potential as a semi-active treatment or part of conventional treatment to precipitate iron
in the mine pool. 相似文献
593.
Katharine R. Stone David S. Pilliod Kathleen A. Dwire Charles C. Rhoades Sherry P. Wollrab Michael K. Young 《Environmental management》2010,46(1):91-100
Two decades of uncharacteristically severe wildfires have caused government and private land managers to actively reduce hazardous
fuels to lessen wildfire severity in western forests, including riparian areas. Because riparian fuel treatments are a fairly
new management strategy, we set out to document their frequency and extent on federal lands in the western U.S. Seventy-four
USDA Forest Service Fire Management Officers (FMOs) in 11 states were interviewed to collect information on the number and
characteristics of riparian fuel reduction treatments in their management district. Just under half of the FMOs surveyed (43%)
indicated that they were conducting fuel reduction treatments in riparian areas. The primary management objective listed for
these projects was either fuel reduction (81%) or ecological restoration and habitat improvement (41%), though multiple management
goals were common (56%). Most projects were of small extent (93% < 300 acres), occurred in the wildland-urban interface (75%),
and were conducted in ways to minimize negative impacts on species and habitats. The results of this survey suggest that managers
are proceeding cautiously with treatments. To facilitate project planning and implementation, managers recommended early coordination
with resource specialists, such as hydrologists and fish and wildlife biologists. Well-designed monitoring of the consequences
of riparian fuel treatments on fuel loads, fire risk, and ecological effects is needed to provide a scientifically-defensible
basis for the continued and growing implementation of these treatments. 相似文献
594.
This research examines how the Kandozi indigenous group governs access to fish and timber for sale and evaluates their perceptions of sustainability of those natural resources. The Kandozi occupy a biodiverse tropical forest in the northern Peruvian Amazon with lakes and seasonally flooded areas. Qualitative methods and a comparative examination of access to resources were used to explore current processes that shape access and the people’s perceptions of their benefit from natural resources. Results indicated that environmental heterogeneity, kinship, land tenure, the legal framework, and knowledge all shaped access with some differences due to the dissimilar natures of fish and timber. This research concludes that the sustainability of this and similar systems are dependent upon the moment at which the analysis is done, because of the changing needs of people over time, in addition to changes in external factors and the natural variations that occur in the resources used. The range of relations and interactions among different processes that shape access, and the historically contingent characteristic of access and its evolution over time, help better understand the complexity of a given social-ecological system. 相似文献
595.
596.
Masako Morishita Gerald J. Keeler Jacob D. McDonald James G. Wagner Li-Hao Young Satoshi Utsunomiya Rodney C. Ewing Jack R. Harkema 《Atmospheric environment (Oxford, England : 1994)》2009,43(10):1805-1813
Recent studies have attributed toxic effects of ambient fine particulate matter (aerodynamic diameter ≤ 2.5 μm; PM2.5) to physical and/or chemical properties rather than total mass. However, identifying specific components or sources of a complex mixture of ambient PM2.5 that are responsible for adverse health effects is still challenging. In order to improve our understanding of source-to-receptor pathways for ambient PM2.5 (links between sources of ambient PM2.5 and measures of biologically relevant dose), integrated inhalation toxicology studies using animal models and concentrated air particles (CAPs) were completed in southwest Detroit, a community where the pediatric asthma rate is more than twice the national average. Ambient PM2.5 was concentrated with a Harvard fine particle concentrator housed in AirCARE1, a mobile air research laboratory which facilitates inhalation exposure studies in real-world settings. Detailed characterizations of ambient PM2.5 and CAPs, identification of major emission sources of PM2.5, and quantification of trace elements in the lung tissues of laboratory rats that were exposed to CAPs for two distinct 3-day exposure periods were completed.This paper describes the physical/chemical properties and sources of PM2.5, pulmonary metal concentrations and meteorology from two different 3-day exposure periods—both conducted at the southwest Detroit location in July 2003—which resulted in disparate biological effects. More specifically, during one of the exposure periods, ambient PM2.5-derived trace metals were recovered from lung tissues of CAPs-exposed animals, and these metals were linked to local combustion point sources in southwest Detroit via receptor modeling and meteorology; whereas in the other exposure period, no such trace metals were observed. By comparing these two disparate results, this investigation was able to define possible links between PM2.5 emitted from refineries and incinerators and biologically relevant dose, which in turn may be associated with observed health effects. 相似文献
597.
Mark T. Young Emily J. Rayfield Casey M. Holliday Lawrence M. Witmer David J. Button Paul Upchurch Paul M. Barrett 《Die Naturwissenschaften》2012,99(8):637-643
Sauropod dinosaurs were the largest terrestrial herbivores and pushed at the limits of vertebrate biomechanics and physiology. Sauropods exhibit high craniodental diversity in ecosystems where numerous species co-existed, leading to the hypothesis that this biodiversity is linked to niche subdivision driven by ecological specialisation. Here, we quantitatively investigate feeding behaviour hypotheses for the iconic sauropod Diplodocus. Biomechanical modelling, using finite element analysis, was used to examine the performance of the Diplodocus skull. Three feeding behaviours were modelled: muscle-driven static biting, branch stripping and bark stripping. The skull was found to be ‘over engineered’ for static biting, overall experiencing low stress with only the dentition enduring high stress. When branch stripping, the skull, similarly, is under low stress, with little appreciable difference between those models. When simulated for bark stripping, the skull experiences far greater stresses, especially in the teeth and at the jaw joint. Therefore, we refute the bark-stripping hypothesis, while the hypotheses of branch stripping and/or precision biting are both consistent with our findings, showing that branch stripping is a biomechanically plausible feeding behaviour for diplodocids. Interestingly, in all simulations, peak stress is observed in the premaxillary–maxillary ‘lateral plates’, supporting the hypothesis that these structures evolved to dissipate stress induced while feeding. These results lead us to conclude that the aberrant craniodental form of Diplodocus was adapted for food procurement rather than resisting high bite forces. 相似文献
598.
Young AL 《Environmental science and pollution research international》2006,13(3):149-150
Chemical residue studies were conducted from 1977-1987 on sites where spills of Agent Orange had occurred in the Herbicide Storage Sites at the Naval Construction Battalion Center, Gulfport, Mississippi, and on Johnston Island, Central Pacific Ocean. The soil persistence time of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) was significantly decreased when in the presence of massive amounts of phenoxy herbicides (> 62,000 microg of herbicide/g of soil). Although microbial populations doubled in the most highly contaminated sites, fungal species diversity decreased. The dominant fungal species that appeared to be associated with the metabolism of the residues were of the genera Penicillium, Mucor, and Fusarium. TCDD level decreased from a mean high of 180 ng/g (ppb) to less than 1 ng/g of soil over a ten-year period. 相似文献
599.
R H Young 《Journal - Water Pollution Control Federation》1972,44(6):1208-1211
600.
William B. Lord James F Booker David M. Getches Benjamin L. Harding Douglas S. Kenney Robert A. Young 《Journal of the American Water Resources Association》1995,31(5):939-944
ABSTRACT: This paper presents a summary of the findings and recommendations of the studies of severe, sustained drought reported in this special issue. The management facilities and institutions were found to be effective in protecting consumptive water users against drought, but much less effective in protecting nonconsumptive uses. Changes in intrastate water management were found to be effective in reducing the monetary value of damages, through reallocating shortages to low-valued uses, while only water banking and water marketing, among the possible interstate rule changes, were similarly effective. Players representing the basin states and the federal government in three gaming experiments were unable to agree upon and effect major changes in operating rules. The conclusions are (1) that nonconsumptive water uses are highly vulnerable to drought, (2) that consumptive uses are well-protected, (3) that drought risk is greatest in the Upper Basin, (4) that the Lower Basin suffers from chronic water shortage but bears little drought risk, (5) that opportunities exist for win-win rule changes, (6) that such rule changes are extremely difficult to make, and (7) that intrastate drought management is very effective m in reducing potential damages. 相似文献