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821.
五箱一体化活性污泥工艺采取交替运行方式,不需要污泥和混合液回流,良好的循环周期设置对系统至关重要,通过试验研究对不同循环周期设置时的处理效果进行了比较,对主体段进水池状态进行了跟踪试验,结果表明,在水力停留时间和泥龄分别为13 h、18 d的条件下,主体段按120 min设置时能形成良好的厌氧释磷条件,磷的释放率达到0.88 gP/kg MLSS·h,主体段、过渡段和沉淀段分别按120、60和60 min的周期设置时TP、TN的去除率达到90%以上. 相似文献
822.
Ferenc L. Tóth 《Integrated Assessment》2000,1(2):127-136
A standard framework is presented as an underlying model for the discounting debate. Views and proposals for the techniques
and rates of discounting are assessed. Alternative modeling frameworks for studying intergenerational equity issues are evaluated
with the result that the basic insights they provide do not differ very much. Results from model experiments involving different
discount rate proposals show that fudging the discount rate does not lead to efficient climate policy. Three major clusters
of opinions are identified regarding the applicability of cost-benefit analysis to the climate change problem and the appropriate
discount rate to use. It is concluded that under some very special circumstances the cost-benefit rule should be abandoned
and cost-effective strategies implying standard discount rates should be sought to reach clearly defined and justified environmental
targets.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
823.
Raymond J. O'Connor Tracey E. Walls Robert M. Hughes 《Environmental monitoring and assessment》2000,61(2):207-229
Biological indicators of communitiestypically reflect a common environmental signalreflecting the general condition of the ecosystem, as well asindividual signals by indicators differentiallysensitive to particular environmental conditions. Wedescribe here a method of integrating and interpretingsuch indicators from 19 New England lakes for fivetaxonomic groups (diatoms, benthos, zooplankton, fish,and birds). Our approach provides a systematicstandardized way to integrate multiple metrics fromdifferent taxonomic groups by addressing four elementscrucial to analyzing data from multiple indicators: covariate control, re-scaling of data, standardizing the sign of responses, and dimensional reduction. We evaluated the biologicalmetrics against individual environmental stressors andagainst multivariate physicochemical metricscharacterizing general anthropogenic stress among thelakes. The method detected a response to variationin the gross environmental condition of the lakes thatwas correlated across taxa and metrics. In addition,a differential response to near shore conditions wasdemonstrated for fish. The success of the approach inthis study lends support to its general application toecological monitoring involving complex data sets. 相似文献
824.
We introduce climate impact response functions as a means for summarizing and visualizing the responses of climate-sensitive
sectors to changes in fundamental drivers of global climate change. In an inverse application, they allow the translation
of thresholds for climate change impacts (‘impact guard-rails’) into constraints for climate and atmospheric composition parameters
(‘climate windows’). It thus becomes feasible to specify long-term objectives for climate protection with respect to the impacts
of climate change instead of crude proxy variables, like the change in global mean temperature. We apply the method to assess
impacts on terrestrial ecosystems, using the threat to protected areas as the central impact indicator. Future climate states
are characterized by geographically and seasonally explicit climate change patterns for temperature, precipitation and cloud
cover, and by their atmospheric CO2 concentration. The patterns are based on the results of coupled general circulation models. We study the sensitivity of the
impact indicators and the corresponding climate windows to the spatial coverage of the analysis and to different climate change
projections. This enables us to identify the most sensitive biomes and regions, and to determine those factors which significantly
influence the results of the impact assessment. Based on the analysis, we conclude that climate impact response functions
are a valuable means for the representation of climate change impacts across a wide range of plausible futures. They are particularly
useful in integrated assessment models of climate change based on optimizing or inverse approaches where the on-line simulation
of climate impacts by sophisticated impact models is infeasible due to their high computational demand.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
825.
综合灾害防御能力评估已成为应急管理业务和研究的重要内容之一.在前期研究基础上,首先从近年来灾害系统的复杂性特征和应急管理的需求角度出发,对综合灾害防御能力进行了再理解,然后对现有灾害防御能力的多属性综合评估方法进行了梳理总结.以气象灾害为例,通过68项指标构建了我国综合气象灾害防御能力的6个单项指标体系,即制度适应能力... 相似文献
826.
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828.
在实验测试基础上,对燃煤烟气喷钙水浴复合脱硫工艺及设备进行了研究.实验表明,采用喷钙水浴复合脱硫工艺较单一喷钙或水浴具有更高的脱硫效果,且喷入的碳酸钙可得到充分利用.此外,还对钙硫比、喷钙方向及喷管插入水深等影响脱硫效率的因素进行了测试分析. 相似文献
829.
采用磺化聚醚砜中空纤维膜萃取醋酸废水,再用CaO—MgO乳状液反萃取制备醋酸钙镁盐。考察了膜萃取和反萃取的最佳实验条件。单级膜萃取醋酸废水(醋酸质量分数2%)的最佳条件为:水相走管程有机相走壳程(水外油内)逆流、有机相流量与水相流量比1.3、水相流量0.23mL/min,在此条件下萃取率可达74%;采用二级萃取,总萃取率可达95%。反萃取的最佳条件为:采用质量浓度100g/L的CaO—MgO乳状液作反萃取剂,CaO—MgO与醋酸摩尔比1.0:2.0,投料钙与镁摩尔比2.9:7.0,反萃取时间30min,室温,在此条件下反萃取率高于97%。 相似文献
830.