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991.
文章分析了我国合成氨工业的特点,污染现状,提出了其水污染物的治理技术,阐明了对相应的排放标准进行适当调整的原因和对新标准进行了说明。 相似文献
992.
The successful management of atmospheric pollution is best achieved when the benefits of controls can be clearly demonstrated to those who the controls affect. There is a need to demonstrate to a population that change will benefit the social and biophysical aspects of that population’s environment as a whole. This paper suggests that policy-makers need to demonstrate clearly the advantages of a change in behaviour for the local environment while concurrently minimising the life-style costs of the people whose co-operation is needed to bring that change about. This requires an improved understanding of the activities affected and the message and media by which environmental benefits can be communicated in the light of that understanding.Using the example of tropospheric ozone, this paper argues that air-quality management requires close regional co-ordination which can facilitate the establishment and implementation of local policy options. The ability of the UK National Air Quality Strategy to achieve this in its present form is discussed and the existence of a strategic gap between the current approach to air-quality management and the major issues surrounding air quality considered. 相似文献
993.
对油田采出水进行处理以净化水质,达到各种目的所要求的水质标准,可采用污水回注的处理工艺,污水作为热采锅炉给水处理工艺,污水外排处理工艺。由于不同的水质要求,具体选择最佳的水处理工艺,达到净化水质保护环境的目的。 相似文献
994.
对照国家环保总局最近发布的GWPB3-1999《锅炉大气污染物排放标准》,对几种日常最常用的中、小型燃煤锅炉进行了达标排放条件下的地面最大落地浓度预测。结果表明,在烟气达标排放和常规气象春造成的地面SO2最大落地浓度在国家环境空气质量标准(二级)的28%以下,远小于规定浓度限值,烟尘的地面影响浓度更可忽略。因此在一般环境影响评价中,只要锅炉烟气做到达标排放,则可不作该两因子的地面浓度预测,由此可大 相似文献
995.
996.
钢管混凝土柱耐火性能和抗火设计的特点 总被引:5,自引:0,他引:5
简要论述了按ISO-834和GS9978-88规定的标准升温曲线升温作用下钢管混凝土柱耐火性能的特点,分析了影响钢管混凝土柱耐火极限的因素,说明了由于钢管和混凝土的共同工作且核心混凝土具有较好的吸热性能,从而使钢管混凝土柱具有较好的耐火性能。在进行钢管钢混凝土柱的抗火设计时,柱子外围只需进行适当的防火涂料保护,即可达到《高层用民建筑设计防火规范(GB50045-95)》对柱结构所要求的耐火极限。《高层用民建筑设计防火规范(GB50045-95)》中对钢结构柱防火保护层厚度的确定方法不适合于钢管混凝土。 相似文献
997.
Concentrations of tropospheric ozone(O3) and exceedance of critical levels to vegetationhave been investigated and mapped for Ireland. Hourlyozone concentration data (1995–1997) at 7 sevenmonitoring stations and the CORINE landcover database,supported by a Geographical Information System, wereused. AOT40 (Accumulated exposure Over a Threshold of 40ppb) was calculated for daylight hours for each station,and mapped using surface interpolation. Average O3concentrations vary from year to year, and were estimatedto be 28 ppb, 26 ppb and 24 ppb for 1995, 1996 and 1997respectively. Ozone concentrations show a large diurnalvariation, with a maximum in the afternoon and a minimumat night-time. The critical level for crops and (semi-)natural vegetation was exceeded in all years examined.The highest exceedance occurred in 1995, where thecritical level was exceeded for almost 35% of the mappedarea. Approximately 15% and 1% of the mapped area wasexposed to exceedance levels during 1996 and 1997respectively. The maximum cumulative exposures (AOT40)were approximately 5000, 3890 and 3230 ppbh in 1995, 1996and 1997 respectively. The critical level for forests wasnot exceeded during the period of investigation. 相似文献
998.
999.
Ren Lefebvre Daryl Hockley Jason Smolensky Ann Lamontagne 《Journal of contaminant hydrology》2001,52(1-4):165-186
Acid mine drainage (AMD) results from the oxidation of sulfides, mainly pyrite, present in mine wastes, either mill tailings or waste rock. This is the second of two papers describing the coupled physical processes taking place in waste rock piles undergoing AMD production. Since the oxidation of pyrite involves the consumption of oxygen and the production of heat, the oxidation process initiates coupled processes of gas transfer by diffusion and convection as well as heat transfer. These processes influence the supply of oxygen that is required to sustain the oxidation process. This second paper describes a numerical simulator used to represent the interaction of these coupled transfer processes. Numerical simulations are applied to two large sites with extensive characterization programs and widely different properties and behavior that were described in the first paper. The South Dump of the Doyon mine in Canada is permeable and has a high pyrite oxidation rate, thus making temperature-driven air convection the main oxygen supply mechanism. The Nordhalde of the Ronnenberg mining district in Germany contains lower permeability material which is less reactive, thus leading to a more balanced contribution of gaseous diffusion and convection as oxygen supply mechanisms. Overall, simulations allow a coherent representation of the conditions monitored within the waste rock piles and the confirmation of their physical properties. Conceptual simulations are also carried out to illustrate the potential effect of border membranes and layered co-mingling as mitigation methods used to control AMD production in either active or future waste rock piles. 相似文献
1000.
E. Gerasopoulos P. Zanis A. Stohl C. S. Zerefos C. Papastefanou W. Ringer L. Tobler S. Hübener H. W. Gggeler H. J. Kanter L. Tositti S. Sandrini 《Atmospheric environment (Oxford, England : 1994)》2001,35(36):294
The 7Be activity concentrations measured from 1996 to 1998 at four high-altitude stations, Jungfraujoch—Switzerland, Zugspitze—Germany, Sonnblick—Austria and Mt. Cimone—Italy, were analyzed in combination with a set of, meteorological and atmospheric parameters such as the tropopause height, relative and specific humidity and also in conjunction with 3D back-trajectories in order to investigate the climatological features of 7Be. A frequency distribution analysis on 7Be activity concentrations revealed the existence of two concentration classes around 1.5 and 6 mBq m−3 and a transition class between the two modes of the distribution at 3–4 mBq m−3. Cross-correlation analysis performed between 7Be and a number of meteorological and atmospheric parameters at the first three stations showed a strong negative correlation with relative humidity (−0.56, −0.51, −0.41) indicating the importance of wet scavenging as a controlling mechanism. Also, the positive correlation with the height of 3-days back-trajectories and tropopause height (+0.49/+0.43, +0.59/+0.36, +0.44/+0.38) shows that downward transport from the upper or middle to lower troposphere within anticyclonic conditions plays also an important role. Trajectory statistics showed that low 7Be concentrations typically originate from lower-altitude subtropical ocean areas, while high concentrations arrive from the north and high altitudes, as is characteristic for stratospheric intrusions. Although the 7Be activity concentrations are highly episodic, the monthly means indicate an annual cycle with a late-summer maximum at all stations. The correlation coefficients calculated for monthly means of the 7Be and atmospheric data suggest that the main predictor controlling the seasonality of the 7Be concentrations is tropopause height (+0.76, +0.56, +0.60), reflecting more vertical transport from upper tropospheric levels into the lower troposphere during the warm season than during the cold season. 相似文献