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251.
在高650 mm、有效容积1 280 mL的液固厌氧流化床单室无膜空气阴极微生物燃料电池(MFC)中,研究了燃料电池串并联产电和有机污水处理性能,同时考察了电极面积、活性炭装填体积、温度等因素对产电性能的影响。结果表明,将燃料电池串联,总电压等于3个单级电池的电压之和,约为2 100 mV,最大功率为0.12 mW,而单级电池最大功率为0.05 mW。并联时,输出电压为800 mV,和单级电池输出电压大体相当,而电流为单级电流的2倍。阳极面积增加1倍,产电量增大了30%;电压随活性炭装填体积的增大而增大;温度为40℃时,燃料电池的产电性能最好。 相似文献
252.
聚丙烯酸钠作为调理剂对好氧堆肥的保氮影响 总被引:2,自引:0,他引:2
实验以污泥、锯末、猪粪为原料,以聚丙烯酸钠(PAAS)为调理剂,利用自制好氧堆肥反应器,研究了PAAS在污泥好氧堆肥中的保氮效果。实验显示,PAAS会提高堆体的pH水平,抑制氨氮的生成,从而减少NH3的挥发源,在PAAS对水溶性氨的吸附作用下,堆肥产品的最终氨氮水平依然得到提高;PAAS对硝化反应有一定的促进作用,添加PAAS的堆体在堆肥周期内的硝氮平均增幅可达到未添加PAAS的空白堆体的4.64倍;添加PAAS的堆体在堆肥周期内全氮平均降幅只有空白堆体的52.24%。PAAS做为堆肥调理剂起到了较为明显的保氮效果。 相似文献
253.
HCl是城市垃圾焚烧产生的主要气体污染物之一。将一种新型脱氯剂TiO2引入到垃圾焚烧系统中,并与其他脱氯剂的性能进行比较。研究了不同脱氯剂使用量、不同反应温度和不同HCl气体浓度对TiO2、CaO和CaTiO3脱氯效果的影响。结果显示,TiO2能在高温(800~1 000℃)、高HCl浓度(1 303.6~1 629.5 mg/m3)下获得较好的脱氯效果。与传统的脱氯剂CaO相比,TiO2更适合于高温烟气脱氯,其在1 000℃时的氯容(36.3 mg HCl/g TiO2)几乎是相同情况下的CaO氯容(9.3 mg HCl/g CaO)的4倍。而CaTiO3的脱氯效果不但受到自身分解效率的影响,还受到TiO2和CaO脱氯效果的影响,其脱氯效果较差。 相似文献
254.
Ruixin Guo Xinkun Ren Hongqiang Ren 《Journal of environmental science and health. Part. B》2013,48(9):883-890
As important members of the zooplankton community and sources of food for fish, rotifers are used extensively in ecotoxicological research to assess the health of the environment and safety of compounds. However, most rotifer toxicity tests are only conducted using rotifer neonates derived from unexposed mothers, thus ignoring the potential transfer of contaminants from mother to offspring. To understand better the mother to offspring exposure, a multigenerational study was conducted using three successive generations (F0, F1 and F2) of the common freshwater rotifer Brachionus calyciflorus to investigate the toxic effects of the widely used organophosphate pesticide, dimethoate (O, O-dimethyl S-methylcarbamoylmethyl phosphorodithioate). When the F0 generation was exposed to five pesticide concentrations, the population growth rate (r) displayed symptoms of hormesis, characterized by the conversion of low-concentration stimulation to high-concentration inhibition. Despite this observation, the exposure to any given concentration of dimethoate reduced the population growth rates of the F1 and F2 generation rotifers. Significant differences existed between the F0, F1 and F2 rotifers for the population growth rate under dimethoate stress: F2 individuals were more sensitive than F1, whereas the F1 individuals were more sensitive than F0. The results indicated that the parental exposure to a given toxic stress could result in increased sensitivity and decreased fitness in the offspring. This study illustrates the utility of multigenerational toxicity tests, which may better reflect and more accurately predict the effects of long-term pesticide exposure to aquatic organisms at the population level. 相似文献
255.
This study focused on the changes of reference evapotranspiration (ET0) and pan evaporation (ETpan) to study the impacts of climate change on the hydrological cycle in the Jinghe River catchment. Based on the Penman–Monteith
equation, the ET0 was calculated. The temporal trend and spatial distribution of ET0 and Epan measured with a 20-cm pan were examined at the 14 stations during 1957–2005. The effects of meteorological factors on the
variation of ET0 were determined by analyzing the trends in themselves with comparison between original climate and detrended climate scenarios
and then their sensitivity to ET0. Both the ET0 and Epan showed remarkable decreasing trends from 1957 to 2005 and their decreasing rate was 40.9 and 17.7 mm per 10 years, respectively.
Trend analysis of meteorological factors exhibited that the reduction in ET0 and ETpan was principally caused by both significant decreases in wind speed and sunshine hours. Furthermore, the decreasing trend
of ET0 was mainly dominated by the significant decrease in wind speed with high sensitivity, to a less extent, by the decrease in
net radiation. Although relative humidity is one of the most sensitive variables, its effect on ET0 was negligible because of its temporal constancy. The contribution of wind speed reduction to decreased ET0 has increased from 50 to 76.1%, but net radiation, by contrast, decreased from 50 to 23.9%. 相似文献
256.
柴油发动机尾气排放中含有比汽油发动机更多的颗粒污染物。文章叙述了尾气净化装置反应原理,触媒及化学稳定性,柴油氧化催化剂和颗粒催化过滤器优点。通过外部加装尾气净化装置,解决了尾气污染问题,具有较好的发展前景、较强的实用性和可操作性。 相似文献
257.
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259.
引入投影降维的思想,将遗传投影寻踪与回归分析技术运用到城市环境质量评价中。将此技术与神经网络方法进行实例比较,投影寻踪回归方法不但可以合理地作出环境质量的综合评价,而且消除了神经网络方法中类别判断不够精确的影响。 相似文献
260.
Cadmium selenium (CdSe) quantum dots (QDs) are semiconductor nanocrystals that hold wide range of applications and substantial production volumes. Due to unique composition and nanoscale properties, their potential toxicity to aquatic organisms has increasingly gained a great amount of interest. However, the impact of CdSe QDs exposure on zebrafish embryo and larvae remains almost unknown. Therefore, the lab study was performed to determine the developmental and behavioral toxicities to zebrafish under continuous exposure to low level CdSe QDs (0.05-31.25 mg L−1) coated with mercaptopropionic acid (MPA). The results showed MPA-CdSe exposure from embryo to larvae stage affected overall fitness. Our findings for the first time revealed that: (1) The 120 h LC50 of MPA-CdSe for zebrafish was 1.98 mg L−1; (2) embryos exposed to MPA-CdSe resulted in malformations incidence and lower hatch rate; (3) abnormal vascular of FLI-1 transgenic zebrafish larvae appeared after exposure to MPA-CdSe including vascular junction, bifurcation, crossing and particle appearance; (4) larvae behavior assessment showed during MPA-CdSe exposure a rapid transition from light-to-dark elicited a similar, brief burst and a higher basal swimming rate; (5) MPA-CdSe induced embryos cell apoptosis in the head and tail region. Results of the observations provide a basic understanding of MPA-CdSe toxicity to aquatic organisms and suggest the need for additional research to identify the toxicological mechanism. 相似文献