IMPACT OF SURFACE COAL MINING ON THREE OHIO WATERSHEDS –PHYSICAL CONDITIONS AND GROUND-WATER HYDROLOGY1

ABSTRACT: A study was conducted over a six-year period in East-Central Ohio to determine the effects of surface mining and reclamation on physical watershed conditions and on ground-water hydrology in three ground-water zones in three small experimental watersheds. Mining disturbances in watersheds adjacent to the experimental sites affected ground-water levels in the undisturbed experimental watersheds prior to actual mining in the experimental sites. New subsurface flow paths, with different characteristics, formed during mining and reclamation. At all three sites mining dewatered the saturated zone above the underclay of the mined coal seam. Mining and reclamation affected ground-water levels below the mined coal seam in the middle and lower zones within at least two sites. Ground-water level recovery in the mined upper saturated zone was slow and irregular both temporally and spatially after reclamation. Hydraulic conductivities of postmining (Phase 3) spoil were generally greater than those of Phase 1 bedrock, but wide spatial variability was observed. Modelers need to be aware of the complexities of new flow paths and physical characteristics of subsurface flow media that are introduced by mining and reclamation, including destruction of the upper-zone clay.     

金属管件在液压机上用模具弯曲成形方法

介绍了金属管件在液压机上用模具弯曲成形的特点及优缺点。     

燃煤火电厂闭路除灰系统结垢及其防治的研究现状

对燃煤火电厂闭路除灰系统结垢及其防治的研究现状进行了叙述和分析，对该领域的研究和发展动向提出了自己的见解     

触摸屏技术在液压压砖机PLC控制系统中的应用

介绍了触摸屏监视器的特点、功能以及在200t全自动液压压砖机PLC控制系统中的应用。     

岩溶裂隙含水层中石油类污染物的迁移与水力截获

对淄博市岩溶地下水遭受石油类污染的研究结果表明，在石灰岩含水层中，岩溶裂隙的发育对石油类污染物侵入地下水的运移过程具有控制作用，石油类污染物沿岩溶裂隙通道运移，在通道延伸的深部可以有高于浅层的检出，水力截获方法去除地下水中石油类污染物是有效的，但水力截获孔的位置应就近污染物集中检出带布置，尽量远离水源地，并正常运行。     

液力挤压法制备新型钨合金穿甲弹芯材料技术

采用液力挤压法制备新型钨合金穿甲弹芯材料,较常规钨合金材料变形加工技术相比,其最大优势是仅通过一次变形可使钨合金材料的性能得到大幅度提高。可对现役、在研各口径、各长细比钨合金穿甲弹进行技术改造和移植。为钨合金穿甲弹芯材料的变形加工提供新的有效技术途径。     

Heterogeneity of chlorinated hydrocarbon sorption properties in a sandy aquifer

Hydraulic conductivity and sorption coefficients for chlorinated hydrocarbons (chloroform, carbon tetrachloride and tetrachloroethylene) were evaluated for 216 sediment samples collected across a 15 m transect and a 21 m depth interval in a contaminated aquifer near Schoolcraft, Michigan. Relationships between hydraulic conductivity, linear sorption partition coefficients, grain size classes, and spatial location were investigated using linear regression analysis and geostatistical techniques. Clear evidence of layering was found in sorption properties, hydraulic conductivity and grain sizes. Conductivity correlated well with grain size, as expected, but sorption varied inversely with grain size, contrary to some previous reports. No significant correlation was found between sorption properties and hydraulic conductivity. This is likely due to the unexpected presence of small amounts of highly sorptive coal-like solids, which dominate the sorption behavior but have little effect on conductivity. The results demonstrate that recent findings regarding the high sorption capacity of coal materials found in soils can exert a controlling influence on contaminant transport. Designers of in situ remediation systems should be cautioned that 1) it is not reasonable to assume that sorption capacity and hydraulic conductivity are related, 2) sorption capacity and hydraulic conductivity are critical measurements for contaminant site characterization and subsequent transport modeling, 3) estimating sorption capacity from organic carbon measurement may lead to greater errors than performing sorption isotherms, and 4) it is more important to characterize vertical heterogeneity rather than horizontal heterogeneity because both sorption and hydraulic conductivity are correlated across longer distances in the horizontal plane.     

多隔室厌氧折流板反应器（ABR）的水力特性试验研究

对ABR反应器的水力流态进行了示踪剂试验，分析了特征截面面积对ABR水力特性的影响，采用停留时间分布（RTD）法研究了不同进水COD浓度和HRT条件下ABR反应器的水力特性，结果表明：不同进水COD浓度时ABR反应器的RTD曲线相似，表明进水COD浓度不是影响ABR水力特性的主要因素；不同HRT条件下RTD曲线差异很大，表明HRT对ABR的水力特性影响较大，随着水力停留时间的延长，Ⅳ值增大，1／Pe减小，ABR的流态趋于推流流态，随着HRT的缩短，Ⅳ值减小，1／Pe数增大，ABR反应器趋于完全混合流态。     

我国空气颗粒物中烃类物质的来源解析研究现状

综述了利用奇偶优势指标、最高峰碳数指标以及色谱峰型特征来判识正构烷烃的来源和利用浓度比值法、化合物的轮廓图特征法、多元统计方法和化学质量平衡法判识多环芳烃的来源,并指出这些方法特点。     

Environmental Impact of Undular Tidal Bores in Tropical Rivers

A tidal bore impacts significantly on the estuarine ecosystem, although little is known on the flow field, mixing and sediment motion beneath tidal bores. In the absence of detailed systematic field measurements, a quasi-steady flow analogy was applied to investigate undular tidal bores with inflow Froude numbers between 1.25 and 1.6. Experimental results indicated that rapid flow redistributions occur beneath the free-surface undulations, with significant variations in bed shear stress between wave crests and troughs. Dynamic similarity was used to predict detailed flow characteristics of undular tidal bores. The effects of periodic loading on river sediments, scour of river bed and flow mixing behind the bore are discussed. A better understanding of these processes will contribute to better management practices in tidal bore affected rivers, including the Styx and Daly rivers in tropical Australia.