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排序方式: 共有1024条查询结果,搜索用时 31 毫秒
941.
In this study, synthesis and speciation of polyaluminum chloride (PAC) for application in water treatment was investigated using a colorimetric speciation method. It was possible to produce stable preparations of PAC solutions in which a relatively stable cationic polymer predominated. The mode of preparation has a dramatic effect on the composition of PAC preparation. Some important parameters such as hydroxyl ligand number, mixing intensity, base injection rate and method, and aging were identified in this study. 相似文献
942.
This article covers the strategic, organizational, and operational decisions involved in one automobile manufacturer's efforts to balance its goals of productivity and high quality with the more elusive goal of environmental responsibility. The case material is based on the real-life experiences of Honda of America's two manufacturing plants in East Liberty and Marysville, Ohio. The case unfolds as the environmental manager in charge of the two plants faces the pending visit of her corporate boss from Tokyo, who has made it clear that environmental issues are of growing importance in Honda's overall direction. ISO 14000, the new environmental quality standards being adopted by some other manufacturers, serves as a focusing issue for the environmental manager's thinking, but this issue is really representative of a wider challenge facing the Ohio plants: balancing Honda's core mission of producing the best cars at the lowest cost possible, and being a responsible actor in the environmental arena. Complicating this challenge, the environmental manager has to negotiate another tension common in global manufacturing firms today: balancing the influence of Honda's corporate headquarters in Japan with the local and regional context at its American plant sites. 相似文献
943.
Brian D. Smith A. K. M. Aminul Haque M. Shakhawat Hossain Anisuzzaman Khan 《Environmental management》1998,22(3):323-335
Platanista gangetica ) are threatened in Bangladesh from the effects of dams, large embankment schemes, dredging, fisheries bycatch, directed hunting,
and water pollution. Visual surveys of the section of the Jamuna River located between the divergence of the Old Brahmaputra
River and the confluence of the Padma River and the section of the Kushiyara River located between the Bangladesh–India border
and the confluence of the Korangi River recorded a sighting rate of 0.13 sightings/km (mean group size = 1.8 dolphins) and
0.08 sightings/km (mean group size = 3.8 dolphins), respectively. These sections of river were considered to be priority areas
for investigation because several water development projects have already been constructed and more are planned for the areas.
During the surveys we examined the remains of dolphins caught accidentally in plastic gillnets and observed fishermen catching
the fish species Clupisoma garua using dolphin oil and body parts as a fish attractor. Additional studies are needed to assess the status of dolphins and
effects of water development and fisheries bycatch. Feasibility studies should be conducted on designating dolphin/fish sanctuaries
and creating artificial habitat or enhancing existing habitat in eddy countercurrent scour pools to mitigate deleterious impacts.
The environmental requirements of river dolphins reflect the needs of productive and biotically diverse tropical rivers. 相似文献
944.
Robert W. Kates Michael W. Mayfield Ralph D. Torrie Brian Witcher 《Local Environment》1998,3(3):279-297
This paper reports on two efforts to develop methods for quantifying and analysing greenhouse gas emissions from local places. The International Council for Local Environmental Initiatives-Cities for Climate Protection (ICLEI-CCP) campaign and the Association of American Geographers-Global Change in Local Places (AAG-GCLP) project represent independent efforts with differing origins and objectives. There is a rich and dynamic fine structure to the causal patterns that determine the level of greenhouse gas emissions in the society. This fine structure is essentially opaque to national and state-level inventories and analyses, and yet understanding it is necessary to understanding how human communities can be organised and human enterprise structured in environmentally sustainable ways. Simplified inventory methods that account for most but not all emissions, use readily available local data and, most important, inform efforts at emission reduction are currently available for cities and could be made available for larger or more diverse local regions or areas. 相似文献
945.
Neckel Alcindo Korcelski Cleiton Silva Luis F. O. Kujawa Henrique Aniceto Bodah Brian William Figueiredo Adriano Marcos Rodrigues Maculan Larcio Stolfo Gonalves Affonso Celso Bodah Eliane Thaines Moro Leila Dal 《Environment, Development and Sustainability》2022,24(9):10728-10751
Environment, Development and Sustainability - The increasing mortality of COVID-19 can aggravate soil contamination by metals, harmful to the health of the population, requiring new projects for... 相似文献
946.
Understanding forest changes and its trajectory is important to develop policy options and future scenarios for climate analysis. This research is conducted to gain insights on secondary forests change using Mississippi, USA, as a case study. We investigate the spatial patterns and temporal dynamics of secondary forests at high resolution and examine the forces driving their changes. An extensive literature review is conducted to refine the conceptual framework of forest changes and identify the underlying key factors. Forest changes are quantified at high spatial (30-m) and temporal (biennial) resolutions, using time series remotely sensed data between 1984 and 2007. A number of geospatial and socioeconomic data were compiled to analyze the spatial variations of forest disturbances and their linkages to various socioeconomic, political, and biogeophysical factors. The results show that the secondary forests are highly dynamic and variable. Disturbances and regeneration occur continuously everywhere in a systematic and coordinated fashion. This pattern prevents an extensive disturbance and increases total forest cover. Market conditions (i.e., timber price) are the key predictor of the level and overall trend of forest disturbances. However, spatial patterns of forest dynamics cannot be explained by location-specific biophysical, socioeconomic, and policy factors identified in the literature. They can best be described by the ecological characteristics of the forests (i.e., the forest type and age distribution), which have a clear economic linkage. The research shows that regenerated forests frequently experience loss and gain of their extent, and their ecological characteristics change drastically on a short-term basis. These results point out challenges and opportunities in forest management and policy with regard to reforestation. 相似文献
947.
948.
Simulating contaminant transport in unsaturated zones with sparse hydraulic property information is a difficult, yet common, problem. When contaminant transport may occur via preferential flow, simple modeling approaches can provide predictions of interest, such as the first arrival of contaminant, with minimal site characterization. The conceptual model for unsaturated zone flow at Rainier Mesa and Shoshone Mountain, Nevada National Security Site, establishes the possibility of preferential flow through lithologies between potential radionuclide sources and the saturated zone. After identifying preferential flow as a possible contaminant transport process, we apply a simple model to estimate first arrival times for conservatively transported radionuclides to reach the saturated zone. Simulated preferential flow travel times at Rainier Mesa are tens to hundreds of years for non-ponded water sources and 1 to 2 months for continuously ponded water sources; first arrival times are approximately twice as long at Shoshone Mountain. These first arrival time results should then be viewed as a worst-case scenario but not necessarily as a timescale for a groundwater-contamination hazard, because concentrations may be very low. The alternative approach demonstrated here for estimating travel times can be useful in situations where predictions are needed by managers for the fastest arrival of contaminants, yet budgetary or time constraints preclude more rigorous analysis, and when additional model estimates are needed for comparison (i.e., model abstraction). 相似文献
949.
950.