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Sang-Woo Lee Ju-Yong Kim Jong-Un Lee IlWon Ko Kyoung-Woong Kim 《Environmental geochemistry and health》2004,26(3-4):403-409
In order to investigate the optimum conditions for the application of soil flushing of arsenic, a batch test was carried out using EDTA at various concentration and pH levels. Based on the optimum condition derived from the batch test, a column test was conducted to examine the feasibility of the soil-flushing technology under field-equivalent conditions. In this column test, a low flushing solution flow rate showed a significantly higher As removal efficiency (71.6%) than a high flow rate (56.3%). TCLP (toxicity characteristic leaching procedure) and a seed germination test were carried out to monitor the toxicity both during and after the treatment. The finally treated tailings were shown to be significantly remediated, having a reduced toxicity by both the TCLP and seed germination tests. 相似文献
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125.
Importance of wax esters and other lipids in the marine food chain: Phytoplankton and copepods 总被引:9,自引:0,他引:9
Wax esters, which function as reserve fuels, account for 25 to 40% of the lipid of the pelagic copepod Calanus helgolandicus (Copepoda, Calanoida). In laboratory experiments with these crustaceans, diatoms (Lauderia borealis, Chaetoceros curvisetus, and Skeletonema costatum) and dinoflagellates (Gymnodinium splendens), which contained no wax esters, were used as food. Changes in the food concentration affected both the amount of lipid and the composition of the wax esters. Since the fatty acids of the triglycerides and wax esters of C. helgolandicus resembled the dietary fatty acid composition, it appeared that copepods incorporated their dietary fatty acids largely unchanged into their wax esters. The polyunsaturated alcohols of the wax esters did not correspond in carbon numbers or degrees of unsaturation to the dietary fatty acids. We postulate two different metabolic pools to explain the origin of these long chain alcohols. The phospholipid fatty acids were not affected by changes in the amount or type of food, probably because of their structural function. 相似文献
126.
Influential factors in freeway crash response and clearance times by emergency management services in peak periods 总被引:1,自引:0,他引:1
OBJECTIVE: Various factors influence the time performance of emergency management personnel when a freeway traffic crash occurs. The proper identification and prioritization of factors that contribute to emergency management services' response times and clearance times result in better usage of taxpayer resources. METHOD: Use of a proportional hazard-based Cox-regression model analyzed statewide, peak-period, traffic crash data from 1999 Ohio logs. These data included time performance measures of emergency management services. RESULTS: Traffic crash severity had the most effect on response times. Those crashes involving injuries or fatalities had up to 20% less emergency management service response times than "property damage only" crashes. Environmental factors such as weather or roadway conditions had minimal effect on response times to traffic crashes. Day of week, urban or rural area, off or opposing-lane crash location, number of vehicles involved, heavy vehicle involvement, and response time significantly affected clearance time and the resulting total time during peak periods. CONCLUSIONS: By assessing resources currently dedicated to insignificant factors, emergency management services can further improve response times to those casualties that crucially need emergency services. By accurately identifying and deciphering traffic crash severity from initial field reports, services can further improve. Moreover, improvements in crash severity prediction reduce "false alarms" for emergency services. The improvements reduce the probability of a very short response time for a property damage only crash in which initial reports implied a very severe injury. By focusing on factors that significantly reduce traffic crash clearance times on freeways in peak periods, more reductions in average delay experienced by freeway users, in fuel consumption, and in motor vehicle emissions can occur. 相似文献
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128.
The aim of this article was to study the effects of land use change and water reuse options on an urban water cycle. A water cycle
analysis was performed on the Goonja drainage basin, located in metropolitan Seoul, using the Aquacycle model. The chronological
e ects of urbanization were first assessed for the land uses of the Goonja drainage basin from 1975 to 2005, where the ratio of
impervious areas ranged from 43% to 84%. Progressive urbanization was identified as leading to a decrease in evapotranspiration
(29%), an increase in surface runo (41%) and a decrease in groundwater recharge (74%), indicating a serious distortion of the water
cycle. From a subsequent analysis of the water reuse options, such as rainwater use and wastewater reuse, it is concluded that wastewater
reuse seemed to have an advantage over rainwater use for providing a consistent water supply throughout the year for a country like
Korea, where the rainy season is concentrated during the summer monsoon. 相似文献
129.
Constructed wetland (CW) is the preferred means of controlling water quality because of its natural treatment mechanisms and
function as a secondary or tertiary treatment unit. CW is increasingly applied in Korea for secondary e uent of livestock wastewater
treatment. This study was conducted to recognize the characteristics of contaminants in the accumulated sediment at the bottom soil
layer and to reduce the phosphorus release from sediments of the free water surface CW for the treatment of secondary piggery
wastewater e uent from a livestock wastewater treatment facility. The results revealed that the dominant phosphorus existence types
at near the inlet of the CW were non-apatite phosphorus (59%) and residual phosphorus (32%) suggesting that most of the particles of
the influent are made up of inorganic materials and dead cells. Sediment accumulation is important when determining the long-term
maintenance requirements over the lifetime of CW. Continuous monitoring will be performed for a further assessment of the CW
system and design. 相似文献
130.
李爱哲 《防灾科技学院学报》2005,7(4):114-116
广告人作为广告业的主体,是广告公司竞争发展的首要因素,也是广告业发展的决定因素。本文从中国广告业迅猛发展的情势入手,分析了中国广告业求贤若渴的势态,以及我国广告从业人员的现状和广告公司需要什么样的广告人等几个要素。 相似文献