Performance-based landfill design: development of a design component selection matrix using GIS and system simulation models

Designing environmentally safe and economically feasible landfills can be a challenging task due to complex interactions that need to be taken into account between landfill size, waste and site characteristics. The main focus of this study is, by interfacing the geographic information systems (GIS) with system simulation models (SSM), to develop a methodology and a landfill design component selection matrix that can enable the determination of landfill design components providing the desired performance with minimal design details. In this paper, the conceptual framework and applications of the developed methodology demonstrating the selection of landfill design components that are suitable for the existing site conditions are presented. The conceptual model defines design variables, performance criteria and design components of a landfill. GIS and SSM are used to handle the site-specific data and to evaluate the landfill performance, respectively. Results indicate that the landfills having the same design characteristics show different performance under different site conditions; therefore, a landfill design that is technically and economically feasible should be selected on the basis of performance.     

用多阶Mueller矩阵解对非均匀地表植被生物量和土壤湿度的迭代反演

根据一层随机非球形粒子矢量辐射传输方程的一阶与高阶Mueller矩阵解的数值模拟及其差异 ,提出了在一些参数已知的条件下 ,用水平与垂直同极化和交叉极化的后向散射测量反演植被覆盖下地表湿度和植被散射元单位面积占空比的迭代方法。利用模拟测量数据以及机载合成孔径雷达 (AirSAR)实测数据 ,对不同土壤湿度和单位面积占空比的情况进行了反演试验     

城市面源SO2允许排放总量的网格分配方法

为了弥补A—P值法的不足，本文以A值法和SSIM模式为基础。提出了一种合理分配城市面源SO2允许排放总量的方法。该方法将A值法计算出的面源SO2允许排放总量作为一个约束条件放入SSIM（Source Strength Inversed Model）模式，调整该模式中各组源强的分担率，直至模式反演出的城市控制区各网格内的面源允许排放量之和与约束条件相等为止，此时模式输出的网格面源SO2允许排放量就是城市控制区内面源SO2允许排放总量的分配结果。应用该方法对石家庄市面源SO2允许排放总量进行网格分配，并采用美国工业源长期浓度复合模式（ISC3LT）对石家庄市SO2总量控制效果进行检验。结果表明：采用该方法分配面源SO2允许排放总量，可保证城市总量控制区内各网格上的SO2浓度值均满足国家标准。     

一种大尺寸遥感图像基于内容检索的纹理特征提取算法

针对50万像素以上的大尺寸遥感图像基于内容检索的需要,通过将大尺寸图像按照区域类别分块,用灰度共生矩阵法对各子块提取出纹理特征,并利用类似Hu的不变矩的方法对各子块纹理信息进行统计,从而提取出与大尺寸图像中各纹理的空间位置相关的一组纹理特征值。该方法对传统的共生矩阵法进行了改进,使其适用于大尺寸图像多区域类别的纹理特征提取,可用于大尺寸遥感图像的基于内容的检索和初分类研究。     

连续梁桥的一种传递矩阵—有限元方法

结构分析的传递矩阵法占用内存贮空间小，运算简便，有限元法划分单元灵活，计算与处理方式统一，适应范围广泛，本文论述了这两种方法存在可相互转化的内部关系，采用子结构思想，提出了将这两种方法有效结合构成一种传递矩阵－有限元方法，一座桥梁结构计算示例表明：该方法不仅计算占用内存小，而且划分单元小，计算与处理方式统一。     

The observation and interpretation of geomagnetic variations in a small area of Hainan Province,China

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Great tritium ages explain the occurrence of good-quality groundwater in a phreatic aquifer of an urban area, Lublin, Poland

The phreatic aquifer of the Lublin chalk in the watershed of the Bystrzyca River, eastern Poland, is characterized by waters of good quality. Its hydraulic conductivity is related to a fissure network of low porosity, as much as 0.006 at the outcrops. The good quality of water in this urban setting is surprising because, according to estimates based on Darcy's law, a high seepage velocity would be expected, resulting in rapid transport of pollutants in the aquifer. However, tritium sampling reveals that the mean ages range from about 55 to 92 years in four cases, and about 250 to 350 years in 11 cases. One sampling site is free of tritium, which indicates an even greater age. Such great ages can be explained only by a retardation of solute transport due to matrix diffusion, that is, an exchange between mobile water in the fissures of low porosity and stagnant water in the matrix of high porosity. The delay factor is given as the ratio of total porosity to fissure porosity. In consequence, all types of dissolved constituents and, to some degree, fine suspended matter are delayed in their transport to springs and wells. In addition, non-conservative constituents have longer times to sorb, react, and decay than in the case of transport without a dominant influence of matrix diffusion. Though pollutants are greatly delayed, their accumulation in the matrix and slow diffusion into the fissures contribute to their persistence in groundwater. Regional values of hydraulic conductivity, estimated from tritium ages and known matrix porosity, agree reasonably well with the values known from pumping tests, which supports the interpretation of a dominant influence of matrix diffusion on solute transport. Electronic Publication     

Empirical Orthogonal Functions Analysis Applied to the Inverse Problem in Hydrogeology: Evaluation of Uncertainty and Simulation of New Solutions

To fulfil the need to generate more realistic solutions, stochastic inverse simulations in hydrogeology are now constrained on both piezometric head and hydraulic conductivity data. These inverse techniques, often based on geostatistics, allow modifications of an initial solution conditioned only on hydraulic conductivity data to arrive at a final solution that also matches observed heads. By repeating the process as many times as necessary with different initial solutions, one generates an ensemble of final solutions thereby addressing the uncertainty of the inverse problem. This requires a method able to handle the whole ensemble and to work on its relevant characteristics. From this standpoint, the analysis by Empirical Orthogonal Functions (EOF) appears promising. The method builds an orthogonal decomposition of the covariance matrix, calculated over the whole set of solutions, and the areas in space where the first functions have a greater influence corresponding to locations of maximum uncertainty in the solutions. These locations depend both on the hydraulic characteristics of the flow problem and on the spatial distribution of available data. The EOF analysis is used on a synthetic problem that mimics a possible behavior of the Culebra aquifer of the Waste Isolation Pilot Plant (WIPP, New Mexico). The method also allows new solutions to be generated at lower computational cost by a random composition of the functions obtained by the EOF analysis. These new solutions keep the main characteristics of the initial ensemble and because they can be conditioned, they return very good results when they are used to solve the direct problem.     

Fitting matrix-valued variogram models by simultaneous diagonalization (Part II: Application)

As an application, we demonstrate a proposed variogram modeling scheme using a spatial data set. Because the scheme relies on a procedure for simultaneously diagonalizing several matrices, we briefly describe the FG and least-squares algorithms. The model obtained by our scheme is used to cokrige the data. In addition, the proposed scheme is compared to more traditional methods.     

用传递矩阵法求解多层层状弹性半空间轴对称动力问题的奇异解

本文利用laplace—Hankel联合变换及传递矩阵技术,导出了多层层状弹性半空间轴对称动力问题在层间完全接触情况下奇异解的一般解析表达式。本文方法概念清晰、公式简洁、易于应用。文中给出了计算实例,所得结果与文献的计算结果吻合较好。