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211.
针对垃圾焚烧炉床层内垃圾燃烧过程复杂性及影响垃圾燃烧效率因素多的问题,运用数值仿真方法对某垃圾焚烧炉床层垃圾燃烧进行了模拟,获得了垃圾质量流失速率、水分蒸发速率、挥发分释放速率、焦炭燃烧速率和烟气的温度;并在50~1 000 Nm3/min范围内改变一次风流量,获得了床层质量流失比值、过剩空气系数和烟气中各组分的质量百分比含量。仿真结果显示,一次风流量取值517.47~6`32.09 Nm3/min时燃烧效率较高;炉排两端区域的一次风流量在50~75 Nm3/min时,可以使垃圾床表面平均温度明显提高,而且还可以提高燃烧效率,同时减少供风总量,节约能源与动力资源。本研究对优化设计垃圾焚烧炉,提高床层内垃圾的燃烧效率有一定参考价值。 相似文献
212.
以太阳光为实验光源研究了氯苯嘧啶醇在水溶液中的光解,考察了pH、水体类型、溶解氧及卤素离子等对其光解的影响.结果表明,氯苯嘧啶醇在水溶液中的光解符合一级动力学方程,在不同水体中氯苯嘧啶醇光解的速率大小顺序为:重蒸水>水库水>湖水>池塘水;氯苯嘧啶醇光解的半衰期随着溶液pH的增大而延长,当pH为5、7、9、11时光解半衰期分别为5.00、6.86、7.45、7.53 h;3种卤素离子对氯苯嘧啶醇光解有很大的影响,均表现出强的猝灭作用,3种离子的猝灭能力的大小顺序为Ⅰ->Br->Cl-;溶解氧和三重态光猝灭剂山梨酸均对氯苯嘧啶醇在水中的光解没有影响,而三重态光敏剂丙酮则对其光解有较强的猝灭作用,表明氯苯嘧啶醇在水中的光解主要以直接光解为主,光解过程不经历三重态. 相似文献
213.
运用系统模型的辨识方法,讨论了环境-经济系统双向控制模型的辨识问题,重点探讨了这类模型体系中的最优控制模型,其途径是采用大系统建模思想.即在对大系统结构分析基础上,通过分解把整体建模转化为易于处理的子系统建模,再通过建立关联模型,得到整体模型,并进一步简化和进行参数辨识. 相似文献
214.
Perinereis aibuhitensis was used to assess adverse biological effects caused by acute and chronic Pb2+exposure in artificial seawater under controlled laboratory conditions. In 96-hr acute toxicity experiments,the morphological changes showed a positive time/dose-dependent tendency,and the 96-hr LC50 value of Pb2+was 686.41 mg/L. The responses of enzymatic and non-enzymatic antioxidants in tissues including catalase(CAT),peroxidase(POD),superoxide dismutase(SOD),glutathione peroxidase(GSH-PX),malondialdehyde(MDA) and the content of total soluble protein(TSP),were investigated on days 1,4,7 and 10 after Pb2+exposure under chronic toxicity testing. Results showed that the activation of the antioxidant system in P. aibuhitensis depended on the Pb2+concentration and the duration of exposure time.Specifically,POD and SOD activities were induced on the first day of the exposure and decreased to the control level on day 10 after exposure. Therefore,these two indexes could be used to indicate oxidative stress associated with P. aibuhitensis exposure to Pb2+. 相似文献
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216.
Arbuscular mycorrhizae enhance metal lead uptake and growth of host plants under a sand culture experiment 总被引:2,自引:0,他引:2
A sand culture experiment was conducted to investigate whether mycorrhizal colonization and mycorrhizal fungal vesicular numbers were influenced by metal lead, and whether mycorrhizae enhance host plants tolerance to metal lead. Metal lead was applied as Pb(NO3)2 in solution at three levels (0, 300 and 600 mg kg(-1) sand). Five mycorrhizal host plant species, Kummerowia striata (Thunb.) Schindl, Ixeris denticulate L., Lolium perenne L., Trifolium repens L. and Echinochloa crusgalli var. mitis were used to examine Pb-mycorrhizal interactions. The arbuscular mycorrhizal inoculum consisted of mixed spores of mycorrhizal fungal species directly isolated from orchard soil. Compared to the untreated control, both Pb concentrations reduced mycorrhizal colonization by 3.8-70.4%. Numbers of AM fungal vesicles increased by 13.2-51.5% in 300 mg Pb kg(-1) sand but decreased by 9.4-50.9% in 600 mg Pb kg(-1) sand. Mycorrhizae significantly enhanced Pb accumulation both in shoot by 10.2-85.5% and in root by 9.3-118.4%. Mycorrhizae also enhanced shoot biomass and shoot P concentration under both Pb concentrations. Root/shoot ratios of Pb concentration were higher in highly mycorrhizal plant species (K.striata, I. denticulate, and E. crusgalli var. mitis) than that in poorly mycorrhizal ones (L. perenne and T. repens,). Mycorrhizal inoculation increased the root/shoot ratio of Pb concentration of highly mycorrhizal plant species by 7.6-57.2% but did not affect the poorly mycorrhizal ones. In the treatments with 300 Pb mg kg(-1) sand, plant species with higher vesicular numbers tended to show higher root/shoot ratios of the Pb concentration. We suggest that under an elevated Pb condition, mycorrhizae could promote plant growth by increasing P uptake and mitigate Pb toxicity by sequestrating more Pb in roots. 相似文献
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219.
Gan Zhang Jun Li Yue Xu Jian-Hui Tang Xiang Liu 《Environmental pollution (Barking, Essex : 1987)》2010,158(11):3392-3400
Carbonaceous aerosols were studied at three background sites in south and southwest China. Hok Tsui in Hong Kong had the highest concentrations of carbonaceous aerosols (OC = 8.7 ± 4.5 μg/m3, EC = 2.5 ± 1.9 μg/m3) among the three sites, and Jianfeng Mountains in Hainan Island (OC = 5.8 ± 2.6 μg/m3, EC = 0.8 ± 0.4 μg/m3) and Tengchong mountain over the east edge of the Tibetan Plateau (OC = 4.8 ± 4.0 μg/m3, EC = 0.5 ± 0.4 μg/m3) showed similar concentration levels. Distinct seasonal patterns with higher concentrations during the winter, and lower concentrations during the summertime were observed, which may be caused by the changes of the regional emissions, and monsoon effects. The industrial and vehicular emissions in East, Southeast and South China, and the regional open biomass burning in the Indo-Myanmar region of Asia were probably the two major potential sources for carbonaceous matters in this region. 相似文献
220.
采用改性粉煤灰(MCFA)吸附糖蜜废水中的有机污染物,对吸附行为和机理进行了考察和分析。结果表明,MCFA投加量为30 g/L及pH为5.0的优化条件下,COD去除率为88.6%,饱和吸附量为89.7 mg COD/g MCFA。准二级方程能更好地描述糖蜜废水在MCFA上的吸附动力学。颗粒内扩散方程结果表明孔扩散并非唯一的速度控制步骤。吸附平衡表明,Freundlich等温线最符合吸附模式,为优惠吸附。D-R模式中的吸附自由能Ea值推断更可能是物理吸附而不是化学吸附。吸附热力学参数ΔG0(<0)、ΔH0(5.130 kJ/mol)和ΔS0(19.936 J/(mol.K))表明MCFA对糖蜜废水的吸附过程为可行的,自发性的吸热反应。 相似文献