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31.
32.
Russell T. Johns Larry W. Lake Abimbola B. Obigbesan Leonardo Bermudez M.R. Hassan Randall J. Charbeneau 《Ground Water Monitoring & Remediation》2003,23(1):97-106
Accidental release of petroleum hydrocarbons to the subsurface may occur through spills around refineries, leaking pipelines, storage tanks, or other sources. If the spill is large, the hydrocarbon liquids may eventually reach a water table and spread laterally in a pancake-like lens. Hydrocarbons that exist as a separate phase are termed light nonaqueous phase liquids (LNAPLs). The portion of the LNAPL that is mobile, not entrapped as residual saturation, is termed "free product."
This paper presents new analytical solutions for the design of long-term free-product recovery from aquifers with skimmer, single- and dual-pump wells. The solutions are for steady-state flow, based on the assumption of vertical equilibrium, and include the effect of coning of LNAPL, air, and water on flow. The solutions are valid for soils of large hydraulic conductivity where the effect of capillary pressure on coning is small.
The results show how to estimate the maximum rate of inflow of LNAPL for skimmer wells, i.e., wells in which LNAPL is recovered with little or no water production. The paper also shows how to calculate the increase in LNAPL recovery when water is pumped by single- or dual-pump wells. A simple equation is given that can be used to adjust the water rate to avoid smearing of the LNAPL below the water table. 相似文献
This paper presents new analytical solutions for the design of long-term free-product recovery from aquifers with skimmer, single- and dual-pump wells. The solutions are for steady-state flow, based on the assumption of vertical equilibrium, and include the effect of coning of LNAPL, air, and water on flow. The solutions are valid for soils of large hydraulic conductivity where the effect of capillary pressure on coning is small.
The results show how to estimate the maximum rate of inflow of LNAPL for skimmer wells, i.e., wells in which LNAPL is recovered with little or no water production. The paper also shows how to calculate the increase in LNAPL recovery when water is pumped by single- or dual-pump wells. A simple equation is given that can be used to adjust the water rate to avoid smearing of the LNAPL below the water table. 相似文献
33.
青藏高原第四纪泛湖期与古气候 总被引:18,自引:3,他引:15
对青藏高原不同位置的17个湖区进行地质调查,并结合卫星照片和地形图解译的基础上,笔者对高原泛湖区形成时间、范围和古气候进行了深入的研究。青藏高原第四纪最晚的两次高湖面(溢流面)时间约为40~30/35ka和65~53ka;在该时段高原为巨大的相互连通泛湖系所覆盖,总面积约达360000km2,湖水总体积约达53×108km3,分别较现代湖泊的总面积和总体积大38倍和659倍。在该泛湖期之前晚更新世还有3次高湖面:132~112ka、110~95ka和约91~72/83~75ka。说明青藏高原晚第四纪气候变化具有不稳定性和快速变化的特点。约40~30ka高湖面还出现在青藏高原以北腾格里沙漠,说明该时期存在特强的南亚夏季风;岁差周期20ka的太阳高辐射变化对位于地球低纬地带、高海拔地区的青藏高原有着特殊的重要性。在30ka前后,伴随青藏高原的快速抬升和古气候变冷,青藏高原周缘泛湖突然外泄,在短时间内巨量冰冷湖水倾泄入印度洋和西太平洋。该泛湖倾泄事件已造成高原周缘江、湖等环境变化。 相似文献
34.
Effect of sediment size on area of influence during groundwater remediation by air sparging: a laboratory approach 总被引:2,自引:0,他引:2
Air sparging is a groundwater remediation technique, in which organic contaminants volatilize into air as it rises from the
saturated to vadose zone. An unknown has been the relationship between sediment size and area affected by air. Laboratory
experiments were performed on sediments to determine the area affected by air as a function of grain size. For average grain
sizes of 1.1 and 1.3-mm diameter, air flow occurs in discrete meandering channels, with a maximum area of sediment column
affected of 13%/m2 for 1.1-mm and 14%/m2 for 1.3-mm sediments. For average grain sizes of 1.84, 2.61 and 4.38-mm diameter, air flow is pervasive, forming a symmetrical
cone of influence around the injection point. Maximum areas affected are15%/m2 for 1.84-mm, 25%/m2 for 2.61-mm, and 9%/m2 for 4.38-mm sediments. Optimal sites for air sparging, may be those with grain diameters between about 2–3 mm.
Received: 26 June 1998 · Accepted: 27 July 1998 相似文献
35.
Mathematical Geosciences - When originally developed, the Koval theory was meant to interpret the core-scale production of oil by a miscible displacement by solvent injection. An essential... 相似文献
36.
Abalone Haliotis diversicolor supertexta is an important economic mollusk.The settlement and metamorphosis are two critical stages during its development period,which has direct influence on abalone survival and production.The influence of reactive oxygen species(hydrogen peroxide) on abalone embryo and juvenile development were examined in this study.Larvae of Haliotis diversicolor supertexta were induced to settlement and metamorphose by exposure to seawater supplemented with hydrogen peroxide.They had the best performance at 800 μmol/L.The concentration of 1 000 μmol/L or higher was toxic to the larvae,as the larvae could settle down only at benthic diatom plates without complete metamorphosis.In addition,H2O2 adding time was critical to the larval performance.24h after two-day post-fertilization was proved to be the optimal adding time.In this paper,two action mechanisms of hydrogen peroxide are discussed:(1) hydrogen peroxide has direct toxicity to ciliated cells,thus cause apoptosis;(2) hydrogen peroxide,as a product from catecholamines' autoxidation process in vivo,can reverse this process to produce neuro-transmitters to induce abalone metamorphosis. 相似文献
37.
- A bold innovation was carried out for the structural type of wharves in line with local conditions in Chiwan Port, in which a group of wharves with novel structures have been built in this port during the past ten years. 相似文献
38.
Recent hydrographic data (1981–1982) from the western Canadian Arctic Archipelago and adjacent areas of the Arctic Ocean are interpreted from the viewpoint of thermal energy transfer. Within the Archipelago, a warmer halocline than in the Arctic Ocean and a cooler Atlantic layer are identified. The warmer halocline is a consequence of the continued diffusion of heat from underlying Atlantic water without a significant downward penetration from the surface of cold (≤1.5°C) seawater with salinity increased consequent to ice growth. The cooler Atlantic layer is primarily attributable to an enhanced cooling of these waters in a narrow band over the continental slope and shelf of the southern Beaufort Sea prior to their inflow into the Archipelago. Rates of transport and vertical diffusion in this region are estimated. The significance of these findings in regional and Arctic oceanography is discussed. 相似文献
39.
The structure of the Weald—a review 总被引:1,自引:1,他引:0
40.
ZHENG Mianping ZHAO Yuanyi LIU JunyingResearch & Development Center of Saline Lake Epithermal Deposits Chinese Academy of Geological Sciences Beijing 《《地质学报》英文版》2000,74(2)
In this paper the authors classify saline lake sediments into the cold, warm and eurythermal phases, reveal the consistency between the zoning of hydrochemical types of modern saline lake water and climatic zoning and give climatic parameters under the conditions of typical cold phase (mirabilite and natron), warm phase (thenar-dite) and slightly warm phase (bloedite) saline lake deposition. 相似文献