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991.
The pyrolysis characteristics of six representative organic components of municipal solid waste (MSW) and their mixtures were studied in a specially designed thermogravimetric analysis apparatus with a maximum recorded heating rate of 864.8 degrees Cmin(-1). The pyrolysis behavior of individual components was described by the Avrami-Erofeev equation. The influence of final temperature on individual components was studied, and it was concluded that final temperature was a factor in reaction speed and intensity, but that it played only a limited role in determining the reaction mechanism. The interactions between different components were evaluated, and it was concluded that the interaction between homogeneous materials was minimal, whereas the interaction between polyethylene and biomass was significant. 相似文献
992.
Effects of initial iron corrosion rate on long-term performance of iron permeable reactive barriers: Column experiments and numerical simulation 总被引:3,自引:1,他引:2
Jin suk O Sung-Wook Jeen Robert W. Gillham Lai Gui 《Journal of contaminant hydrology》2009,103(3-4):145-156
Column experiments and numerical simulation were conducted to test the hypothesis that iron material having a high corrosion rate is not beneficial for the long-term performance of iron permeable reactive barriers (PRBs) because of faster passivation of iron and greater porosity loss close to the influent face of the PRBs. Four iron materials (Connelly, Gotthart-Maier, Peerless, and ISPAT) were used for the column experiments, and the changes in reactivity toward cis-dichloroethene (cis-DCE) degradation in the presence of dissolved CaCO3 were evaluated. The experimental results showed that the difference in distribution of the accumulated precipitates, resulting from differences in iron corrosion rate, caused a difference in the migration rate of the cis-DCE profiles and a significant difference in the pattern of passivation, indicating a faster passivation in the region close to the influent end for the material having a higher corrosion rate. For the numerical simulation, the accumulation of secondary minerals and reactivity loss of iron were coupled using an empirically-derived relationship that was incorporated into a multi-component reactive transport model. The simulation results provided a reasonable representation of the evolution of iron reactivity toward cis-DCE treatment and the changes in geochemical conditions for each material, consistent with the observed data. The simulations for long-term performance were also conducted to further test the hypothesis and predict the differences in performance over a period of 40 years under typical groundwater conditions. The predictions showed that the cases of higher iron corrosion rates had earlier cis-DCE breakthrough and more reduction in porosity starting from near the influent face, due to more accumulation of carbonate minerals in that region. Therefore, both the experimental and simulation results appear to support the hypothesis and suggest that reactivity changes of iron materials resulting from evolution of geochemical conditions should be considered in the design of iron PRBs. 相似文献
993.
长江流域年平均气温的时空变化特征 总被引:3,自引:0,他引:3
利用长江流域146个气象站点1960~2005年的逐年气温资料,选用EOF和REOF方法识别长江流域年平均气温空间变化特征,并对长江流域年平均气温变化敏感区域进行时间演变分析和突变检测。研究表明:长江流域年平均气温主要有2种空间振荡型(即全流域气温变化趋向一致型和流域内气温变化存在东西向差异型),3个变化敏感区域(长江流域中下游地区、长江流域南部和金沙江流域)。3个变化敏感区域的年平均气温都在20世纪90年代明显升高,且均在90年代后期呈突变增加,其中金沙江流域升温趋势最为明显,气候倾向率为0.20℃/10a。全流域1991~2005年年平均气温距平空间分布表明,自1991年以来全流域都为升温趋势,其中长江流域中下游地区和金沙江流域是升温幅度最大的地区。 相似文献
994.
Distribution of polybrominated diphenyl ethers in breast milk from North China: Implication of exposure pathways 总被引:1,自引:0,他引:1
The breast milk concentrations of polybrominated diphenyl ethers (PBDEs; sum of eight congeners: BDE-28, 47, 99, 100, 153, 154, 183 and 209) were determined (by high resolution gas chromatographic high resolution mass spectrometry) in samples from primiparous women collected in 2006 in Tianjin, China. Dietary and lifestyle habits of the participants were obtained by questionnaires. The median total PBDE concentration (including BDE-28, 47, 99, 100, 153, 154, 183) was 2500 pg g−1 lipid weight, ranging from 1700 to 4500 pg g−1 lipid weight. These levels were in the same range as those from Europe and Japan but much lower than those from North America. The congener profile in China was also different from other countries. The contribution of BDE-28 was around 15%, much higher than any other country, implying that a different Penta-BDE formulation might be used in the Chinese market. The lower ratio of the sum of BDE-47, 99, and 100 to the sum of BDE-153 and 154 suggested that Octa-products were in more demand in China. A significant correlation was found between a woman’s PBDE concentration and the time she used electronic appliances (h/d). This implies that electronics are a potential source of PBDEs to people. Inhalation or ingestion of particulate matter (such as dust) may also be an important exposure pathway. There was no significant correlation between the PBDE concentration and the consumption of meat, fish, and milk. Further research is needed to determine the specific contribution of each exposure route and their health effects. 相似文献
995.
996.
997.
抗生素废水碱回收与生化处理试验研究 总被引:1,自引:0,他引:1
为克服抗生素废水难以生化处理的难题,采用废碱液回收利用和生物强化处理的技术手段对废水进行了资源化小试研究。结果显示,经碱液回收后出水的COD、SS、硫酸盐和含盐量分别由13 925、45 700、417和29 900 mg/L降到了2 400、86、25和402 mg/L,色度也由6 000倍降到了5倍;经与综合污水混合后生化强化处理,出水COD、色度和硫酸盐的平均去除率分别达到了91%、84%和96.5%,处理效果理想,资源化技术处理废水可盈利54.19元/t,具有较好的经济性,值得推广应用。 相似文献
998.
接种0~4℃贮存2个月亚硝酸盐反硝化颗粒污泥,以甲醇为电子供体、亚硝酸盐为电子受体在USB(上流式污泥床)反应器内进行二次启动。结果显示,在逐步提高进水负荷下,约46 d完成了反应器二次启动,污泥床负荷达到3.43 g N/(L·d),NO2-N去除率为99%;在稳定运行阶段,当进水NO2-N浓度为50 mg/L、负荷从1.7 g N/(L·d)逐步提高至5.1 g N/(L·d)时,NO2-N去除率均大于98%;当表观流速为2.68 m/h、进水负荷逐步提高至8.0 g N/(L·d)时,脱氮率下降至63%,过程中污泥床最大去除速率约为5.7 g N/(L·d)。研究认为,亚硝酸盐颗粒污泥床具有稳定和去除效率高等特点。 相似文献
999.
1000.
2009年10月1日是新中国成立60周年的日子,中国正面临多方位的检视,其核心问题之厂是未来中国安全发展的途径。2009年5月26日,由本人出任课题组长的北京减灾协会完成了北京市发展与改革委员会下达的“十二五”期间北京市提升城市综合减灾应急管理水平的重点、思路及对策研究》项目申报书, 相似文献