Predicting Freshwater Critical Loads from Catchment Characteristics using National Datasets

Maps of freshwater critical loads are used toguide emission strategies for sulphur and nitrogen bothnationally and internationally. Water chemistry data arerequired to calculate critical loads and the production ofnational maps therefore relies on the existence of extensivechemistry datasets. However, the data required to calculatecritical loads are not readily available for all sites. Thisarticle explores how empirical statistical models mightpotentially be used to predict critical loads using nationallyavailable datasets representing a range of catchmentcharacteristics. Initially a global regression model forexplaining freshwater critical load variation across a broadspectrum of catchment types (from lowland agricultural tomountain lakes) throughout mainland Britain is described. Whenattention is focused on more specific catchment types (i.e.upland and non-arable) it is shown that the global model hasless explanatory power. A regionalisation of Great Britain(based on 100 km grid squares) shows that the global modelcannot necessarily be applied successfully within a narrowerregional context. Separate analyses were undertaken on each ofthe regional subsets using backward selection regression. Thevariables emerging as significant predictors variedsubstantially across the regions, as did the explanatory powerof the models. This was also the case when the analysis wasconfined to upland and non-arable catchments. This approachcould be developed so that critical loads assessments can bemade for populations of standing waters rather than simplythose for which water chemistry is available.     

以控制资源消耗量为突破口做好环境保护规划

提出了稳态、非稳态社会经济系统在环境方面的基本关系式.着重说明了资源消耗量是源头上的"因",而环境质量是最终的"果".提出了以控制资源消耗量为重点,进一步完善末端治理,提高环境自净能力,标本兼治的环境保护工作思路.介绍了编制环保规划要掌握的2个基本公式.强调了单位(以104元计)GDP环境负荷及其年下降率的重要性.穿越"环境高山",应成为制定规划的目标.按计划管理模式,编制环境保护规划,在我国可能是完全必要的.      

降雨过程中气溶胶湿沉降的数值模拟

为了参数化降雨湿去除气溶胶的过程,首先定量计算了雨滴和气溶胶的碰撞效率与它们尺度之间的依存关系,以及雨滴尺度谱满足对数正态分布时气溶胶的清除系数与其尺度的依存关系;然后利用多重Monte Carlo算法模拟了降雨过程中气溶胶尺度谱的时间演变过程,考察了气溶胶湿沉降过程与降雨类型和雨强的相关性.当雨滴尺度谱和气溶胶尺度谱均满足对数正态分布时,数值模拟的结果表明,典型的小雨、中雨和大雨过程对中等尺度气溶胶的湿去除效果均不理想,但都可以有效地湿去除大尺度气溶胶和小尺度气溶胶;3种降雨类型对大尺度气溶胶的湿去除效果均依次好于小尺度气溶胶和中等尺度气溶胶;对于任何尺度的气溶胶,雨强的增加将有利于其湿沉降.     

有机磷农药对乙酰胆碱酯酶的抑制作用及QSAR研究

以碘化硫代乙酰胆碱为底物,二硫代二硝基苯甲酸为显色剂,采用分光光度法测定了21种有机磷农药对乙酰胆碱酯酶(AChE)的半抑制浓度(IC₅₀).运用多元线性回归分析以及参数间的自相关分析建立有机磷农药对AChE抑制作用的QSAR模型.模型分析表明,有机磷农药对AChE的抑制作用主要受特定方向上的原子极化率及原子的电拓扑状态的影响,是多因素综合作用的结果.模型可解释高达78%的数据变异和显著的预测能力(q²=0.653),表明有机磷农药对AChE的抑制作用可借助结构活性关系模型进行预测与评价.     

水处理滤料润湿性的实验研究

基于Washburn方程用亲油亲水比(LHR)比较了无烟煤、沸石和石英砂滤料对油的润湿选择性,并对其表面结构进行了表征.结果表明,无烟煤、沸石和石英砂的LHR值依次为2.41、0.64和0.65,沸石和石英砂的亲水性明显好于无烟煤,而无烟煤的亲油性好于沸石和石英砂.这主要取决于滤料的表面化学组成,同时与其表面形貌有一定的关系,与SEM、XPS、FTIR分析结果基本吻合.     

Assessing the demand of solid waste disposal in urban region by urban dynamics modelling in a GIS environment

The twentieth century saw a dramatic increase in the production of urban solid waste, reflecting unprecedented global levels of economic activity. Despite some efforts to reduce and recover the waste, disposal in landfills is still the most usual destination. However, landfill has become more difficult to implement because of its increasing cost, community opposition to landfill siting, and more restrictive environmental regulations regarding the siting and operation of landfills. Moreover, disposal in landfill is the waste destination method with the largest demand for land, while land is a resource whose availability has been decreasing in urban systems. Shortage of land for landfills is a problem frequently cited in the literature as a physical constraint. Nonetheless, the shortage of land for waste disposal has not been fully studied and, in particular, quantified. This paper presents a method to quantify the relationship between the demand and supply of suitable land for waste disposal over time using a geographic information system and modelling techniques. Based on projections of population growth, urban sprawl and waste generation the method can allow policy and decision-makers to measure the dimension of the problem of shortage of land into the future. The procedure can provide information to guide the design and schedule of programs to reduce and recover waste, and can potentially lead to a better use of the land resource. Porto Alegre City, Brazil was used as the case study to illustrate and analyse the approach. By testing different waste management scenarios, the results indicated that the demand for land for waste disposal overcomes the supply of suitable land for this use in the study area before the year 2050.     

A model of the air traffic controller's picture

This paper reviews the development of a model of the air traffic controller's mental image, ‘picture’, or situation awareness, used for controlling air traffic. The computerised model's development, origins and theoretical basis are outlined, and the model is described in some detail in the context of current air traffic operations. The model can be utilised to explore the potential impacts of future automation on the cognitive performance of the air traffic controller. The general potential contributions of the area of cognitive modelling to system design and training in accelerating industries such as air traffic control, are also discussed.     

Integrated Simulation and Modelling Approach to Decision Making and Environmental Protection

This paper's objective is first to test the application of computer simulation and modelling tools in investigating the effects of applying sustainable manufacturing practices in a smelter plant, and second, to prove quantitatively and visually that 'sustainibility is free'. A simulation model is built to test and capture two different operating polices, 'Policy 1' and 'Policy 2', of an industrial system. In the case study, the simulation model is designed to reflect the effects of decision making in the activites found in a smelter plant, and to quantify the cost, sustainable and environmental consequences based on the decisions. Apart from providing a means of accurately measuring a system's performance, the purpose of using simulation tools is also to link the economic factors, such as productivity and total costs, as well as the sustainable factors, such as natural resource and energy consumption of a system. The simulation results prove quantitatively and visually that sustainability is not only 'free' but is, in fact, a far better proposition for economic growth in the medium to longer term than traditional forms of management.     

基于事故树和模糊层次分析法的飞机火灾事故分析

为了解决飞机火灾事故易发问题、降低事故发生率,以巡航过程中客机发生火灾事故为情境,提出事故树分析法和模糊层次分析法相结合的研究方法。绘制树形图研究人为、机械、环境和管理等方面导致飞机火灾事故发生的途径,构建飞机火灾事故指标体系,结构重要度对指标赋值得出权重值顺序,结果表明:安检和安全培训对飞机火灾事故发生影响最大,空气影响次之,机械故障影响最小。因此,最有效的飞机火灾事故预防途径应从可燃物控制方面着手。     

Evaluation of near surface ozone in air quality simulations forced by a regional climate model over Europe for the period 1991–2000

This study aims to evaluate near surface ozone simulated with the modelling system RegCM3/CAMx against ozone measurements from the EMEP database for the recent decade 1991–2000. The RegCM3/CAMx simulations were performed on a 50 km × 50 km grid over Europe driven either by ERA-40 reanalysis (hereafter referred as ERA simulation) or the global circulation model (GCM) ECHAM5 (hereafter referred as ECHAM simulation). A set of statistical metrics is used for the model evaluation, including temporal correlation coefficient, the ratio of the standard deviations and the bias of simulated versus observed values. Overall, a good agreement is found for both ERA and ECHAM simulations at the majority of the selected EMEP stations in all metrics throughout the year based either on monthly or daily ozone values. Based on these results, it is assessed that the modelling system RegCM3/CAMx is suitable to be used for present and future regional climate-air quality simulations with emphasis on near surface ozone. The ERA simulations reproduce more accurately the observed ozone values in comparison to ECHAM simulations because the meteorology of the ERA experiment is closer to real atmospheric conditions than the GCM based experiment. On a seasonal basis, both ERA and ECHAM simulations exhibit a seasonally dependent bias, with winter and spring ozone values being generally under-estimated by the model and summer and autumn values being slightly overestimated. This seasonally dependent bias is also evident from median and peak midday ozone values. However, the highest observed midday ozone peaks in summer, with values higher than 80 ppbv, could not be captured either by ERA or ECHAM simulations. An analysis of day-time and night-time ERA and ECHAM modelled ozone values shows that CAMx performs better during the day-time.