Improving Efficiency Of Uncertainty Analysis In Complex Integrated Assessment Models: The Case Of The Rains Emission Module

Abstact Ever since the Regional Acidification Information and Simulation Model (RAINS) has been constructed, the treatment of uncertainty has remained an issue of major interest. In a recent review of the model performed for the Clean Air for Europe (CAFE) programme of the European Commission, a more systematic and structured uncertainty analysis has been recommended. This paper aims at contributing to the scientific debate how this can be achieved. Because of its complex structure on the one hand and limited research resources (time, computational capacities) on the other hand a full-blown uncertainty analysis in RAINS is hardly feasible. Therefore, all types of uncertainty require more efficient ways for uncertainty analysis. With respect to parameter uncertainty, we propose to focus research efforts for uncertainty analysis on key parameters. Among different approaches to select key parameters that have been discussed in the literature screening methods seem to be particularly appropriate for complex, deterministic Integrated Assessment models such as RAINS. Surprisingly, in Integrated Assessment modelling for air pollution problems of screening design have not been taken up so far. As a case study we consider the emission module of RAINS. We show that its structure allows for a straightforward and effective screening procedure     

动荷载作用下地下岩体洞室应力特征的影响因素分析

用FLAC3D初步分析了动荷载作用下埋深、洞室形状、地应力特征对地下岩体洞室应力特征的影响。分析结果表明:动荷载下,随着埋深的增加,各种洞型应力量值有明显的减小趋势;地应力状态对地形洞室的应力响应有较明显的影响,在自重地应力为主的情况下,洞室拱顶、拱底地最小主应力处于拉应力状态,而构造地应力为主的情况下,洞室拱顶、拱底最小主应力处于压应力状态,且随着侧压系数的增加,洞室的应力由较明显的减小趋势;动荷载作用下,不同断面形状的洞型应力响应有一定区别,圆形洞室应力响应最小,矩形洞室应力响应最大,随埋深、地应力的增加,洞形对洞室应力响应影响减小,当埋深超过300 m后,洞型对应力的影响变化程度不大。     

基于MATLABR的水质模型参数的确定方法

基于MATLAB可靠的数值计算、强大的绘图功能和简单易学的语言体系,利用MATLAB对河流水质模型的参数进行最优化估值,同时确定模型中的各个参数.指出MATLAB在运用最优化方法于水质模型多参数求解中的作用.提出了以C语言为基础的算法思想.     

Modelling the biological performance of a side-stream membrane bioreactor using ASM1

Membrane bioreactors(MBRs) are attracting global interest but the mathematical modeling of the biological performance of MBRs remains very limited. This study focuses on the modelling of a side-stream MBR system using Activated Sludge Model No. 1 (ASM1), and comparing the results with the modelling of traditional activated sludge processes. ASM1 parameters relevant for the long-term biological behaviour in MBR systems were calibrated(i, e. YH = 0.72gCOD/gCOD, YA = 0.25gCOD/gN, bH = 0.25 d^-1, bA = 0.080 d^-1 and fp =0.06), and generally agreed with the parameters in traditional activated sludge processes, with the exception that a higher autotrophic biomass decay rate was observed in the MBR. A sensitivity analysis for steady state operation and DO dynamics suggested that the biological performance of the MBR system (the sludge concentration, effluent quality and the DO dynamics) are very sensitive to the parameters(i.e. YH, YA, bH, hA, μmaxH and μmaxA), and influent wastewater components( X1, Ss, Xs, SNH).     

扩散参数的不确定性及其对扩散因子的影响

根据联邦行署卡尔斯鲁厄核研究中心３１次示踪实验结果,定量估算了高架源,大粗糙度地形条件下,各类天气相应的扩散参数的不确定度。发现同一地点,同一天气类型,扩散参数实测值相差可达二个量级,σｙ的不确定度随天气类型由Ａ至Ｆ类而变大。采用拉丁超立方取样方法估算了上述扩散参数不确定度实测值所导致的小时轴向扩散因子的不确定度。     

产酸相最佳发酵类型工程控制对策

对二相厌氧消化工艺的研究证明,产酸发酵阶段对整个厌氧生物处理系统运行的成败起着关键的作用,作为产酸发酵三种类型之一的乙醇型发酵被证明是产酸相的最佳发酵类型。采用连续流二相厌氧生物处理系统,对产酸相乙醇型发酵在实际工程中能够直接控制的运行参数进行了研究与探讨。试验结果表明,产酸相乙醇型发酵的最佳参数：温度为34～38℃,pH为4.0～4.4,Eh为－300～－400mV,HRT为5～6h;污泥负荷应不大于4gCOD/gVSS·d,以2.5gCOD/gVSS·d最佳。     

拱顶储罐气相层惰化过程数值模拟及工艺参数研究

针对油罐在检测、维修前须先将气相层可燃气体用氮气惰化到安全浓度,现场凭经验操作效率低且难以掌握氮气合理用量,容易造成氮气浪费或达不到安全浓度引发事故的问题,为确保惰化过程的安全经济,以常见拱顶储罐为例,首先利用改进后的公式法得出多组分可燃气体惰化效果评价指标;然后根据所得指标采用仿真对储罐气相层惰化过程进行数值模拟,并验证了仿真结果的正确性;最后采用仿真计算方法开展储罐气相层氮气惰化工艺参数的影响研究。研究结果表明:惰化效率与进口压力无关,只随进口流速变化,且大于1 m/s流速后,惰化效率已显著变化,此时可以增加进口管道数量,进一步提高惰化效率。理论研究结果可为现场实施提供参考和指导。     

How have we,do we,and will we measure time perspective? A review of methodological and measurement issues

Despite the demonstrated importance of time perspective on key outcomes, its growing popularity, and its wide reach in terms of samples and disciplines, the construct has been plagued with definitional and measurement problems since its inception. Given the historical and current confusion regarding both conceptualization and operationalization, the purpose of this article is to provide an overview of methodological and measurement issues related to time perspective. Clearly, definitional and measurement clarity are critical for the success of future research. Through integrating the fragmented and eclectic time perspective literature fraught with ambiguity, we help to clarify measurement options and their psychometric evidence for future researchers. Specifically, we provide an in-depth comparison of four (and their offshoots) commonly used, scale-based measures of time perspective with respect to their dimensional content, psychometric properties, and validation evidence. We end with recommendations for time perspective research.     

汽车后排座椅侧气囊仿真系统参数优化研究

为提升侧面碰撞中后排乘员胸腹部保护效果,在国内某款汽车原有侧面碰撞系统模型基础上,构建后排座椅侧气囊(RSAB)仿真试验模型,通过各项零部件试验与气囊模型对标后导入侧面碰撞系统试验模型;分析RSAB及气帘对后排被试的保护性能,针对胸腹部损伤防护优化侧面气囊相关参数,设计正交试验,运用极差分析法,得出最优参数组合,并对比...     

Hydro-chemical Survey of Groundwater of Hisar City and Assessment of Defluoridation Methods Used in India

Ground water quality of Hisar city was assessed for its suitability for drinking purposes. Samples collected from the Bore-wells (forms a part of municipal water supply) and handpumps (direct consumption) were analyzed for the various physico-chemical parameters including pH, electrical conductivity, total dissolved salts, total hardness, total alkalinity, sodium, potassium, calcium, magnesium, carbonate, bicarbonate, chloride and sulfate. The concentrations of magnesium, sodium, potassium, sulfate and especially of chloride were found moderately higher than the WHO standards for the drinking water. Further a comparison of fluoride (F⁻) levels in groundwater of various cities and towns of Haryana state was performed. The relatively higher concentrations of F⁻ in groundwater of Haryana raise the risk of fluorosis and hence groundwater must be used with proper treatment. Promising defluoridation methods using locally available materials and technologies are discussed for the prevention and control of fluorosis. Data were assessed statistically to find the suitable markers of ground water quality as an aid to monitoring groundwater quality.