The Application of Water Feature Model for Water-bursting Source Judgment at the First Mining Face of Under-group Coal Seams

通过对淄博矿业集团公司岱庄煤矿影响下组煤开采的3个主要含水层以前所做的大量水质化学成分化验结果的资料整理,建立了该矿下组煤主要充水水源的水质特征模型。根据最近突水点水质特征指标与已建立的水质特征模型进行综合对比,准确及时地确定了突水水源。     

固相萃取-离子色谱法测定地下水中痕量高氯酸根离子

建立了测定地下水中痕量高氯酸根（ClO~4）的固相萃取-离子色谱(SPE-IC)分析方法。0.7 L水样经预处理降低主要干扰离子Cl~、CO2~3和SO2~4的干扰后,使用Cleanert PWAX弱阴离子交换固相萃取小柱对地下水中痕量(μg/L级)的ClO~4进行富集,用6 mL 1%NaOH溶液洗脱,富集液经0.45 μm水膜过滤后,用IonPac AS20阴离子分离柱、50 μL进样环、40 mmol/L KOH溶液淋洗、抑制电导检测分离分析。结果表明,地下水样品中ClO~4的方法检出限和测定下限分别为0.15 μg/L和0.60 μg/L,进样质量浓度在1～15 μg/L范围内有很好的线性关系,线性相关系数为0.9992,回收率为99.7%～100.5%;该方法经济有效,可用于地下水中痕量ClO~4的检测。利用该方法测定了哈尔滨周边部分地区地下水中ClO~4浓度,检测结果与离子色谱-质谱联用法的检测结果的相对误差为1.85%～9.24%。     

地下水流并行有限层方法及同伦反演研究

根据有限层求解格式存在的解耦性,实现了地下水三维流问题的高效并行化计算。在此基础上,结合非线性同伦方法,提出了地下水参数反演分析的并行同伦算法,利用MATLAB编译了相应的正反演计算程序。与已有解析解和有限差分解的对比以及数值算例,验证了并行化正反演方法及程序的正确性,探讨了并行算法的计算效率。研究表明,并行方法可以有效提高计算速度,较串行方法具有明显优势,同时同伦反演方法具有大范围收敛的特点,不依赖于参数值的初始选取。     

The isotope altitude effect reflected in groundwater: a case study from Slovenia

This paper presents the stable isotope data of oxygen (δ¹⁸O) and hydrogen (δ²H) in groundwater from 83 sampling locations in Slovenia and their interpretation. The isotopic composition of water was monitored over 3 years (2009–2011), and each location was sampled twice. New findings on the isotopic composition of sampled groundwater are presented, and the data are also compared to past studies regarding the isotopic composition of precipitation, surface water, and groundwater in Slovenia. This study comprises: (1) the general characteristics of the isotopic composition of oxygen and hydrogen in groundwater in Slovenia, (2) the spatial distribution of oxygen isotope composition (δ¹⁸O) and d-excess in groundwater, (3) the groundwater isotope altitude effect, (4) the correlation between groundwater d-excess and the recharge area altitude of the sampling location, (5) the relation between hydrogen and oxygen isotopes in groundwater in comparison to the global precipitation isotope data, (6) the groundwater isotope effect of distance from the sea, and (7) the estimated relation between the mean temperature of recharge area and δ¹⁸O in groundwater.     

基于Entropy-Topsis的区域系统发展脆弱性分析与测评

脆弱性是区域系统发展历程中出现扰动的本质内因,脆弱性的优化调整有利于区域系统自身的功能完善、干扰缓冲、环境适应以及发展演进;本文界定和解析区域系统发展脆弱性的内涵,设置区域系统发展脆弱性测评指标和判别准则,建立基于Entropy-Topsis的区域系统发展脆弱性测评模型,收集黑龙江省1999～2007年度的统计资料开展实证研究,深入分析测评结果的演进规律和经济内涵,为区域规划和调整策略的制定提供参考依据.     

Analysis of Vulnerability on Weighted Power Networks under Line Breakdowns

Vulnerability is a major concern for power networks. Malicious attacks have the potential to trigger cascading failures and large blackouts. The robustness of power networks against line failure has been of interest in the past several years. However, this scenario cannot cover weighted situations in the real world. This paper investigates the vulnerability of weighted power networks. Firstly, we propose a more practical capacity model to investigate the cascading failure of weighted power networks under different attack strategies. Results show that the smaller threshold of the capacity parameter can enhance the vulnerability of weighted power networks. Furthermore, a weighted electrical cyber-physical interdependent network is developed to study the vulnerability and failure dynamics of the entire power network. We perform simulations in the IEEE 118 Bus case to evaluate the vulnerability under various coupling schemes and different attack strategies. Simulation results show that heavier loads increase the likelihood of blackouts and that different coupling strategies play a crucial role in the cascading failure performance.     

Two approaches to modeling unstable flow and mixing of variable density fluids in porous media

Density variation of aqueous phase fluids flowing in a porous medium, resulting from spatial and temporal variation of solute concentration, often gives rise to unstable flow, and therefore has a significant effect on solute transport. Studies on simulating unstable flow and mixing of variable density fluids in seemingly homogeneous porous media are rare. In this study, a three-dimensional (3-D) and a one-dimensional (1-D) model were developed to simulate unstable flow and mixing in a vertical, nominally 1-D system. In the 3-D model, the fluid flow and solute transport equations were solved numerically with a very fine spatial discretization. The 1-D numerical model was derived from a theoretical model to simulate the flow and mixing of fluids with variable density and viscosity at the field scale. To evaluate the models, simulated results were compared with experimental data from displacement experiments in a vertical sand column. The results show that the 1-D model provides fairly good prediction of breakthrough curves and that the 3-D model is able to qualitatively simulate breakthrough curves for highly unstable flow and mixing.Contribution from the Alabama Agric. Exp. Sta. as AAES Journal No. 3-955037.     

Integrated numerical model for vegetated surface and saturated subsurface flow interaction

The construction of an integrated numerical model is presented in this paper to deal with the interactions between vegetated surface and saturated subsurface flows. A numerical model is built by integrating the previously developed quasi-three-dimensional (Q3D) vegetated surface flow model with a two-dimensional (2D) saturated groundwater flow model. The vegetated surface flow model is constructed by coupling the explicit finite volume solution of 2D shallow water equations (SWEs) with the implicit finite difference solution of Navier-Stokes equations (NSEs) for vertical velocity distribution. The subsurface model is based on the explicit finite volume solution of 2D saturated groundwater flow equations (SGFEs). The ground and vegetated surface water interaction is achieved by introducing source-sink terms into the continuity equations. Two solutions are tightly coupled in a single code. The integrated model is applied to four test cases, and the results are satisfactory.     

Well Hydraulics with the Weber–Goldstein Transforms

Two new integral transforms, ideally suited for solving boundary value problems in well hydraulics, are derived from one of the Goldstein identities which generalizes a corresponding Weber identity. The two transforms are, therefore, named the Weber–Goldstein transforms. Their properties are presented. For the first, second, and third type boundary conditions, the new transforms remove the radial portion of a Laplacian in the cylindrical coordinates. They are used to straightforwardly rederive known solutions to the problems of a fully penetrating flowing well and a fully penetrating pumped well. A novel solution for a fully penetrating flowing well with infinitesimal skin situated in a leaky aquifer is also found by means of one of the new transforms. This solution is validated by comparison to a numerical solution obtained via the finite-difference method and to a quasi-analytic solution obtained by numerical inversion of the corresponding solution in the Laplace domain. Based on the new solution, a flowing well test is proposed for estimating the hydraulic conductivity and specific storativity of the aquifer and the skin factor of the well. The test can also be used in a constant-head injection mode. A type-curve estimation procedure is developed and illustrated with an example. The effectiveness of the test in estimating the well skin factor and aquifer parameters depends on the availability of data on the sufficiently early well response.     

Analysis of diphenylarsinic acid in human and environmental samples by HPLC–ICP‐MS

A simple, rapid and robust analytical method for determining diphenylarsinic acid in human and environmental samples was developed based on a combination of hydrophilic polymer‐based gel‐permeation high‐performance liquid chromatography (HPLC) and inductively coupled plasma mass spectrometry (ICP‐MS). Hair and nail samples were digested with alkali, and liberated diphenylarsinic acid (derivative) was extracted with diethyl ether, redissolved in water and injected for HPLC–ICP‐MS analysis. Human urine, groundwater and water extracts from soils were injected for HPLC–ICP‐MS directly after filtration. Using the method, diphenylarsinic acid in a solution was quantified in 7 min duration for an analysis with a detection limit of sub‐nanograms per milliliter. The method has been applied to groundwater arsenic pollution recently uncovered in Japan. Copyright © 2005 John Wiley & Sons, Ltd.