Application of a Bayesian approach to stochastic delineation of capture zones

This paper presents a Bayesian Monte Carlo method for evaluating the uncertainty in the delineation of well capture zones and its application to a wellfield in a heterogeneous, multiaquifer system. In the method presented, Bayes' rule is used to update prior distributions for the unknown parameters of the stochastic model for the hydraulic conductivity, and to calculate probability-based weights for parameter realizations using head residuals. These weights are then assigned to the corresponding capture zones obtained using forward particle tracking. Statistical analysis of the set of weighted protection zones results in a probability distribution for the capture zones. The suitability of the Bayesian stochastic method for a multilayered system is investigated, using the wellfield Het Rot at Nieuwrode, Belgium, located in a three-layered aquifer system, as an example. The hydraulic conductivity of the production aquifer is modeled as a spatially correlated random function with uncertain parameters. The aquitard and overlying unconfined aquifer are assigned random, homogeneous conductivities. The stochastic results are compared with deterministic capture zones obtained with a calibrated model for the area. The predictions of the stochastic approach are more conservative and indicate that parameter uncertainty should be taken into account in the delineation of well capture zones.     

Determining extreme parameter correlation in ground water models

In ground water flow system models with hydraulic-head observations but without significant imposed or observed flows, extreme parameter correlation generally exists. As a result, hydraulic conductivity and recharge parameters cannot be uniquely estimated. In complicated problems, such correlation can go undetected even by experienced modelers. Extreme parameter correlation can be detected using parameter correlation coefficients, but their utility depends on the presence of sufficient, but not excessive, numerical imprecision of the sensitivities, such as round-off error. This work investigates the information that can be obtained from parameter correlation coefficients in the presence of different levels of numerical imprecision, and compares it to the information provided by an alternative method called the singular value decomposition (SVD). Results suggest that (1) calculated correlation coefficients with absolute values that round to 1.00 were good indicators of extreme parameter correlation, but smaller values were not necessarily good indicators of lack of correlation and resulting unique parameter estimates; (2) the SVD may be more difficult to interpret than parameter correlation coefficients, but it required sensitivities that were one to two significant digits less accurate than those that required using parameter correlation coefficients; and (3) both the SVD and parameter correlation coefficients identified extremely correlated parameters better when the parameters were more equally sensitive. When the statistical measures fail, parameter correlation can be identified only by the tedious process of executing regression using different sets of starting values, or, in some circumstances, through graphs of the objective function.     

可持续发展之七大问题--评价矿业活动对可持续性的贡献之问题框架

矿业对可持续发展的贡献一直是各界关注的问题 ,为详细评价矿业对可持续发展的贡献 ,矿业、矿产与可持续发展 (MMSD)小组北美组设计了评价矿业项目或矿业活动对可持续发展的贡献的问题框架。该小组根据焦点问题法设计了 7个最受关注的能够反映矿业对可持续性贡献的问题 ,包括公众参与、人类健康、环境稳定、经济发展能力、制度安排和政府管理能力以及综合状况 ,并就每个问题给出了“理想答案” ,以便就此评价和引导矿业公司的可持续发展行为。该问题框架目前已经处于试用阶段 ,而且已为森林、水产业等部门所采用。     

LANDSLIDE POTENTIALITY OF THE TSENGWEN RESERVOIR WATERSHED, TAIWAN

To recognize the geographical characteristics of the landslide areas will be helpful for the watershedmanagement in the reservoir watershed. According to the quantitative analysis, we'll take differentscores and weighting for the potential parameters of the landslide areas in the Tsengwen reservoirwatershed, and in the meanwhile, we'll extract the different factors, including the slope, aspect,altitude, soil and geological textures etc., and the results shown as maximum one--day rainfall, ratio offorests and average relief is the most affecting parameters on the potential risk map of landslide areas.     

DISCONTINUOUS FLOW OF TURBID DENSITY CURRENTS II.INTERNAL HYDRAULIC JUMP

1 INTERNAL HYDRAULIC JUMPS AND LOCAL WATER ENTRAINMENT Traveling and stationary internal hydraulic jumps in two-layer flow can occur in the following situations (Fig. 1). When a stratified fluid flows over an obstacle created by a sudden blockage, the layer of increased depth within the heavier fluid will propagate upstream as a traveling hydraulic jump. When the heavier fluid overtops the obstacle it will flow along the downstream face of the obstacle as a supercritical flow…     

第21章：地震图的结构及解释

地震图的解释是用于识别地震记录上出现的且形成相当复杂结构的各种地震波（震相）的技艺。正确识别所记录的震相及该震相在地球内部的传播路径是所有利用地震观测数据进行研究的途径。一幅地震图的形态反映了震源、传播路径、仪器特性和接收台站周围噪声的共同作用。理解地震图的复杂结构需要震源物理、地球结构和地震波传播的知识。总之，需要有分析地震波的长期经验。一个经验丰富的地震图分析员经常可发现并正确解释新手们不能察觉的记录特征，     

地震勘探中的时间-暴光声学

本文提出用于地下成像无源地震方法的分析,在该方法中应用环境地震噪声作为地下散射体的照明源。该成像算法能够以递归方式将新的数据融入到成像中,这使成像背景噪声随时间减少。在空间域不相干环境背景噪声的假设前提下推导出成像算法的点-扩展函数。点-扩展函数表征成像的分辨率,即接收排列长度和环境带宽的函数。     

Lead isotopes in lacustrine sediments and lichen transplants, contrasting and complimentary indicators of sources

The isotopic composition of lead has proven a powerful tool for the characterization of the types of its sources, and with other information on their identity. Lead is dispersed in the environment through water courses or airborne particulates, and has serious impact on the natural and human environments. Lake sediments record deposition derived mainly from its catchment while lichen represents the fine-grained atmospheric deposition of the site. The records of deposition differ in the scales of grain size, time and space. This investigation aims at comparing and contrasting these two types of records in an area affected essentially by a single visible emission source, and to improve the understanding of the controls on the formation of these records. The visible source is a Cu smelter complex with mining installations within the town of Karabash, in the southern Ural Mountains of Russia and considered one of the most heavily polluted areas in the world.     

Experimental Studies on Elasticities of Forsterite-Enstatite Composites:Towards an Understanding of the Rules of Mixture

Which rule of mixture is the best for predicting the overall elastic properties of polyphase rocks based on the elastic properties and volume fractions of their constituents? In order to address this question, we sintered forsterite-enstatite polycrystalline aggregates with a varied forsterite volume fraction (0, 0.2, 0.4, 0.5, 0.6, 0.8, and 1.0). Elastic properties (shear, bulk, and Young's moduli) of these synthesized composites were measured as a function of pressure up to 3.0 GPa in a liquid-medium piston-cylinder apparatus using a high-precision ultrasonic interferometric technique. The experimental data can be much better described by the shear-lag model than by the commonly used simple models such as Voigt, Ruess and Hill averages, Hashin-Shtrikman bounds, Ravichandran bounds, Halpin-Tsai equations, and Paul's calculations. We attributed this to the fact that the elastic interaction and stress transfer between phases are neglected in all the models except for the shear-lag model. In particular, t     

西峪煤矿带压开采对晋祠泉水影响的分析

从水文地质角角出发,结合多年的井下防治水工作实践,对西峪煤矿的带压开采与地下水之间的关系进行了详细的分析研究,得出西峪煤矿及西山局各矿的带压开采均不会影响晋祠泉水的结论。