排序方式: 共有14条查询结果,搜索用时 31 毫秒
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基于RuO2-IrO2/Ti形稳电极和Fe0牺牲电极实现电氧化-电絮凝(EO-EC)一体化处理含Tl (I)废水,并与单一的电絮凝(EC)进行比较,探讨了EO-EC处理含Tl废水的机理.结果表明,相较于单一EC,EO-EC (1:1)组合技术适应于宽pH (4-10)以及电流密度范围(5-20mA/cm2)下含Tl废水高效处理,且不易发生钝化;活性氯以及氧化还原电位在Tl (I)间接氧化Tl (III)过程中扮演重要角色,沉淀分析表明生成的Tl (OH)3(s)与絮体Fe (OH)3(am)共沉淀,纤铁矿位点可吸附残留Tl (I).EO-EC一体化技术可满足实际含Tl废水达标处理(<2µg/L)且具有经济可行性. 相似文献
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Scahill J Wolfrum EJ Michener WE Bergmann M Blake DM Watt AS 《Journal of the Air & Waste Management Association (1995)》2004,54(1):105-110
The use of sorbents has been proposed to remove volatile organic compounds (VOCs) present in ambient air at concentrations in the parts-per-billion (ppb) range, which is typical of indoor air quality applications. Sorbent materials, such as granular activated carbon and molecular sieves, are used to remove VOCs from gas streams in industrial applications, where VOC concentrations are typically in the parts-per-million range. A method for evaluating the VOC removal performance of sorbent materials using toluene concentrations in the ppb range is described. Breakthrough times for toluene at concentrations from 2 to 7500 ppb are presented for a hydrophobic molecular sieve at 25%) relative humidity. By increasing the ratio of challenge gas flow rate to the mass of the sorbent bed and decreasing both the mass of sorbent in the bed and the sorbent particle size, this method reduces the required experimental times by a factor of up to several hundred compared with the proposed American Society of Heating, Refrigerating, and Air-Conditioning Engineers method, ASHRAE 145P, making sorbent performance evaluation for ppb-range VOC removal more convenient. The method can be applied to screen sorbent materials for application in the removal of VOCs from indoor air. 相似文献
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M. Downs R. Michener B. Fry K. Nadelhoffer 《Environmental monitoring and assessment》1999,55(1):211-220
The difficulty of measuring 15N in dilute solutions has limited the potential of ecosystem labeling experiments and model comparisons. By concentrating the N from large (up to 20 L) water samples on ion-exchange resin columns, we obtained enough N for accurate and reproducible 15N measurement using the Teflon tape diffusion method. Analysis of standards demonstrated >95% recovery of inorganic N from samples, and 15N values comparable to those obtained using standard distillation methods. The value of the blank at our laboratory was 0.16 moles N. Analytical precision was within 2 15N when samples of streamwater from the Bear Brook Watersheds (1800 eq · ha-1 · yr-1 N addition at 192 15N) were kept frozen until analysis. The analytical process is lengthy, but once set up can easily be performed for large numbers of samples. 相似文献
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Christian C. Voigt Otto von Helversen Robert Michener Thomas H. Kunz 《Behavioral ecology and sociobiology》2001,50(1):31-36
Saccopteryx bilineata has a polygynous mating system in which males defend females in a harem territory. Harem defense and courtship include energetically costly flight maneuvers and hovering displays. We tested if (1) harem males have a greater field metabolic rate than non-harem males or females and if (2) the field metabolic rate of harem males is correlated with the number of females in a harem territory. We measured the energy budget in 32 S. bilineata with the doubly labeled water method and compared these estimates with behavioral observations in the daytime roost. Among adult bats, field metabolic rate varied with body mass by an exponent of approximately two. We found no significant difference in field metabolic rate or mass-specific field metabolic rate between harem and non-harem males. The mass-specific field metabolic rate of harem-males increased with harem size. The latter finding supports the hypothesis that the energy costs of courtship display and territorial defense influence the energy budget of harem males. Overall, field metabolic rates of S. bilineata were lower than those of similarly sized bats of the temperate zone and only 2.3 times above the basal metabolic rate recorded for this species. We suggest that male S. bilineata did not take advantage of their metabolic capacity because a prudent allocation of energy to activities of harem maintenance is an adaptive strategy for males in this mating system. 相似文献
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Gail R. Michener 《Behavioral ecology and sociobiology》1980,7(3):173-178
Summary The reproductive success of ten female Richardson's ground squirrels resident on a grassland pasture in southern Alberta in 1975 was determined by noting the number of their descendants present in 1976, 1977, and 1978.The two most successful females were the progenitors of 67% of the females resident in 1977 and of 57% of the females resident in 1978. None of the other eight females had descendants in the population in 1978. The two most successful females produced more daughters than did the other females and they did so, not by rearing larger litters, but by producing female-biased litters. The daughters of the two most successful females lived slightly longer than did the daughters of other females.Although the adult sex ratio was strongly female biased each breeding season, ranging between 0.26 and 0.42 males per female, typically all females became pregnant.Adult female offspring inherited their mother's home range and, if the mother or any female sibs were present, shared this area with them. Sons rarely remained resident in or near the natal area and adult males rarely remained resident in the same area for two consecutive years. Thus, post-weaning investments were greater in daughters than in sons.There were no conclusive correlations between sex ratio of litters and size of litters, age of the mother, previous reproductive success of the mother, population density, or the length of the overwinter period. More studies spanning several generations are required to elucidate the effects of the sex ratio of litters on the likelihood of an animal being represented by descendants in subsequent generations. 相似文献
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Hale SS Miglarese AH Bradley MP Belton TJ Cooper LD Frame MT Friel CA Harwell LM King RE Michener WK Nicolson DT Peterjohn BG 《Environmental monitoring and assessment》2003,81(1-3):133-148
Understanding the ecology, condition, and changes of coastal areas requires data from many sources. Broad-scale and long-term ecological questions, such as global climate change, biodiversity, and cumulative impacts of human activities, must be addressed with databases that integrate data from several different research and monitoring programs. Various barriers, including widely differing data formats, codes, directories, systems, and metadata used by individual programs, make such integration troublesome. Coastal data partnerships, by helping overcome technical, social, and organizational barriers, can lead to a better understanding of environmental issues, and may enable better management decisions. Characteristics of successful data partnerships include a common need for shared data, strong collaborative leadership, committed partners willing to invest in the partnership, and clear agreements on data standards and data policy. Emerging data and metadata standards that become widely accepted are crucial. New information technology is making it easier to exchange and integrate data. Data partnerships allow us to create broader databases than would be possible for any one organization to create by itself. 相似文献
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John Scahill William E. Michener Michael Bergmann Daniel M. Blake Andrew S. Watt 《Journal of the Air & Waste Management Association (1995)》2013,63(1):105-110
Abstract The use of sorbents has been proposed to remove volatile organic compounds (VOCs) present in ambient air at concentrations in the parts-per-billion (ppb) range, which is typical of indoor air quality applications. Sorbent materials, such as granular activated carbon and molecular sieves, are used to remove VOCs from gas streams in industrial applications, where VOC concentrations are typically in the parts-per-million range. A method for evaluating the VOC removal performance of sorbent materials using toluene concentrations in the ppb range is described. Breakthrough times for toluene at concentrations from 2 to 7500 ppb are presented for a hydrophobic molecular sieve at 25% relative humidity. By increasing the ratio of challenge gas flow rate to the mass of the sorbent bed and decreasing both the mass of sorbent in the bed and the sorbent particle size, this method reduces the required experimental times by a factor of up to several hundred compared with the proposed American Society of Heating, Refrigerating, and Air-Conditioning Engineers method, ASHRAE 145P, making sorbent performance evaluation for ppb-range VOC removal more convenient. The method can be applied to screen sorbent materials for application in the removal of VOCs from indoor air. 相似文献