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781.
论山风对重庆雾形成和发展的作用 总被引:4,自引:0,他引:4
本文着重分析了通过市中区、长江和嘉陵江剖面上的系留气艇探空资料,研究了浓雾生消过程中剖面上各气象要素场的连续变化.结果表明,山风、城市热岛和两江水面对雾的形成和发展起着重要作用. 相似文献
782.
783.
常州盘固水泥有限公司在新建4 500t·d-1水泥熟料生产线的同时,配套建设了低温余热发电,项目建成后,吨水泥能耗下降11%,窑头烟气粉尘削减量为2%,年增直接经济效益2 603万元,真正实现了节能减排增效的目标. 相似文献
784.
膜—生物反应器特性影响因素研究 总被引:8,自引:0,他引:8
通过对外压管式膜组件与曝气池构成的好氧膜生物反应器的研究,分别考究膜组件的操作压力,膜面流速以及活性污泥混合液的污泥浓度,溶解性有机特的含量和温度等对膜通量的影响。 相似文献
785.
786.
不确定数据条件下的生命周期评价及其应用 总被引:5,自引:0,他引:5
针对产品生命周期评价中普遍存在着的不确定性数据问题,提出基于概率统计的方法,进行生命周期评价以及重要环境影响清单参数的识别与灵敏度分析。结合水源中央空调系统,建立了统计平均意义下的污染排放清单,运用MonteCarlo模拟获得了以均值219.746和方差9.4243所表征的空调机系统生命周期环境影响的概率分布。进一步通过K—S检验与灵敏度分析,识别出10个具有重要环境影响贡献的清单参数及其中4个对环境影响分布较敏感的参数。以概率分布代替固定数值可以反映产品环境绩效的统计信息,能够有效地用于不确定数据条件下的产品生命周期评价。 相似文献
787.
788.
S. Christensen P. Ambus J.R.M. Arah H. Clayton B. Galle D.W.T. Griffith K.J. Hargreaves L. Klenzedtsson A.-M. Lind M. Maag A. Scott U. Skiba K.A. Smith M. Welling F.G. Wienhold 《Atmospheric environment (Oxford, England : 1994)》1996,30(24):4183-4190
The soil in a drained fjord area, reclaimed for arable farming, produced N2O mainly at 75–105 cm depth, just above the ground water level. Surface emissions of N2O were measured from discrete small areas by closed and open-flow chamber methods, using gas chromatographic analysis and over larger areas by integrative methods: flux gradient (analysis by FTIR), conditional sampling (analysis by TDLAS), and eddy covariance (analysis by TDLAS). The mean emission of N2O as determined by chamber procedures during a 9-day campaign was 162–202 μg N2ONm−2h−1 from a wheat stubble and 328–467 μg N2ONm−2 h−1 from a carrot field. The integrative approaches gave N2O emissions of 149–495 μg N2ONm−2 h−1, i.e. a range similar to those determined with the chamber methods. Wind direction affected the comparison of chamber and integrative methods because of patchiness of the N2O emission over the area. When a uniform area with a single type of vegetation had a dominant effect on the N2O gradient at the sampling mast, the temporal variation in N2O emission determined by the flux gradient/FTIR method and chamber methods was very similar, with differences of only 18% or less in mean N2O emission, well below the variation encountered with the chamber methods themselves. A detailed comparison of FTIR gradient and chamber data taking into account the precise emission footprint showed good agreement. It is concluded that there was no bias between the different approaches used to measure the N2O emission and that the precision of the measurements was determined by the spatial variability of the N2O emission at the site and the variability inherent in the individual techniques. These results confirm that measurements of N2O emissions from different ecosystems obtained by the different methods can be meaningfully compared. 相似文献
789.
A flux estimate of PCDDs and PCDFs through a waste water treatment plant has been made on an annual basis. The samples were collected from different steps in the treatment procedure within the plant i.e. inlet and outlet water, different sludge types and air samples. From the surroundings of the plant were collected samples of urban air, storm sewer water (urban runoff), plant discharge water and settling particulates from a sediment trap downstream the plant discharge. Differences in congener profiles were found between the samples taken within the plant compared to those collected outside. The flux of PCDD and PCDF equivalents through the plant was found to be approximately 0.4 – 0.5 g/year and the major part was taken away as digested sludge. 相似文献
790.