How nature uses overland flow regime to maximize equilibrium detention storage and flood attenuation     

Tommy S. W. Wong 《水文研究》2008,22(26):5004-5012

Equilibrium detention storage is an important parameter as it has a proportional effect on flood attenuation. In this paper, based on the kinematic wave theory, a working formula for the equilibrium detention storage of an overland plane with upstream inflow has been derived. Since the flow regime over a concrete plane can vary throughout the entire range laminar to turbulent, this case has been selected to examine the effect of flow regime on the equilibrium detention storage. In the examination, the derived formula has been applied to four flow regimes: (a) laminar, (b) transitional, (c) near turbulent, and (d) turbulent. The examination shows that for planes with a small discharge, laminar flow gives the maximum detention storage. For planes with a medium discharge, transitional flow gives the maximum detention storage, and for planes with a large discharge, near turbulent flow gives the maximum detention storage. The flow regime can cause more than two‐fold increase in detention storage. All these results can be attributed to the respective flow resistance, and have been endorsed with analyses of the water surface profile and the rising limb of the hydrograph. Finally, relating the results to real‐life situations, it shows that the flow regime that gives the maximum detention storage is also the dominating flow regime in nature. Hence, extraordinarily, the flow regimes that exist in nature in fact provide maximum flood attenuation. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

A modular injection system, multilevel sampler, and manifold for tracer tests   总被引：1，自引：0，他引：1  

Mailloux BJ  Fuller ME  Rose GF  Onstott TC  DeFlaun MF  Alvarez E  Hemingway C  Hallet RB  Phelps TJ  Griffin T 《Ground water》2003,41(6):816-827

Ground water injection and sampling systems were developed for bacterial transport experiments in both homogenous and heterogeneous unconsolidated, surficial aquifers. Two types of injection systems, a large single tank and a dynamic mixing tank, were designed to deliver more than 800 L of amended ground water to the aquifer over 12 hours, without altering the ground water temperature, pH, Eh, or dissolved gas composition. Two types of multilevel samplers (MLSs) were designed and installed. Permanent MLSs performed well for the homogenous surficial aquifer, but their installation procedure promoted vertical mixing, which could obfuscate experimental data obtained from vertically stratified, heterogeneous aquifers. A novel, removable MLS was designed to fit in 2- and 4-inch wells. Expandable O-rings between each sampling port hydraulically isolated each port for sample collection when a nut was tightened at the land surface. A low-cost vacuum manifold system designed to work with both MLS designs used 50 mL centrifuge tubes to efficiently sample 12 MLS ports with one peristaltic pump head. The integrated system was developed and used during four field campaigns over a period of three years. During each campaign, more than 3000 ground water samples were collected in less than one week. This system should prove particularly useful for ground water tracer, injection, and push-pull experiments that require high-frequency and/or high-density sampling.  相似文献   

Procedures for Sampling Deep Subsurface Microbial Communities in Unconsolidated Sediments   总被引：2，自引：0，他引：2  

Brent F. Russell  Tommy J. Phelps  William T. Griffin  Kenneth A. Sargent 《Ground Water Monitoring & Remediation》1992,12(1):96-104

A corehole sampling project utilizing a wireline coring system provided sediment samples for microbiological characterization from deep unconsolidated sediments. Sampling tools were developed or modified to minimize contamination during sample acquisition and to facilitate stringent decontamination requirements. Quality assurance procedures, including the use of tracers, were implemented to minimize and quantify contamination from drilling hardware, drilling fluids and sample processing. Tracers included microspheres, potassium bromide, rhodamine dye, and perfluorocarbons, which enabled the detection and measurement of 1mg of drilling fluid per kg of sediment. In addition, sample processing was performed on-site in an anaerobic chamber to prevent exposure of the subsurface materials to atmospheric oxygen concentrations. Sediment samples were then disbursed to investigators at National Laboratories and universities funded through the Department of Energy Subsurface Science Microbiology Program for microbiological characterization. Results of these efforts demonstrated that representative subsurface samples were collected and disbursed.  相似文献   

Estimating seepage from a reservoir from change in hydraulic head     

James W. Naney  Tommy B. Thompson 《Journal of Hydrology》1979,40(3-4):201-213

An investigation of seepage below floodwater-retarding structures conducted by the U.S.D.A. Science and Education Administration Federal Research resulted in a method for estimating seepage from a reservoir based upon change in head. A typical structure was selected for the study and physiographic and geologic features of the site were identified. Extensive hydrologic and hydrogeologic data were collected and analyzed for the site. A major inflow event was recorded in the reservoir in September 1965 and data from that event were used to develop an equation for estimating the amount of seepage lost from the structure in relation to the hydraulic head behind the structure. The method presented by the authors provides a physically based method for estimating the impact of a reservoir on the groundwater flow system assuming variable reservoir head conditions.  相似文献   

Clam burrowing behaviour: Inhibition by copper-enriched sediment     

H. L. Phelps  J. T. Hardy  W. H. Pearson  C. W. Apts 《Marine pollution bulletin》1983,14(12):452-455

Burrowing behaviour is adaptive and allows clams to escape predation; yet the effects of potentially toxic metals on such behaviour have not been adequately investigated. In natural marine sediment contaminated with copper the time for littleneck clams (Protothaca staminea) to achieve complete burial was recorded. Above a threshold of 5.8 μg g⁻¹ Cu added to dry sediment, the time for 50% of the clams to burrow (ET₅₀) increased logarithmically with increasing sediment copper concentration according to: where ET₅₀=time in hours for 50% of clams to burrow and Cu=μg g⁻¹ Cu in dry sediment. Previously exposed clams had both a lower threshold to Cu and a longer reburrowing time (ET₅₀). Clams exposed to sediment mixed with Chelex-100®-sorbed copper showed no significant change in burrowing time. Bioassays based on claim burrowing behaviour can measure both bioeffectiveness of sediment-sorbed metals and a sublethal effect with ecological meaning.  相似文献   

Annotated bibliographies of mineral deposits in Europe: by John D. Ridge. Pergamon Press,Oxford, 1984, $120.00     

Tommy B. Thompson 《Organic Geochemistry》1985,8(2):193-194

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美国西部克罗拉多Cripple Creek地区浅成低温金-碲化物矿床成因及相关之碱性火成岩     

苑丽  ＫａｒｅｎＤ．Ｋｅｌｅｙ  ＨｏlｌｙＪ．Ｓｔｅｉｎ  ＬａｗｒｅｎｃｅＷ．Ｓｎｅｅ  ＤａｖｉｄＷ．Ｂｅａｔｙ  ＴｏｍｍｙＢ．Ｔｈｏｍｐｓｏｎ 《地质与资源》1997,6(2):156-157

美国西部克罗拉多ＣｒｉｐｐｌｅＣｒｅｅｋ地区浅成低温金－碲化物矿床成因及相关之碱性火成岩自１８９１年发现至今，ＣｒｉｐｐｌｅＣｒｅｅｋ地区已产金６５３ｔ之多，成为全美第二大金产地．金矿床产于被元古宙基底岩石包围着的狭小的（１８ｋｍ２）渐新统火山杂岩中...  相似文献   

Interactions of plasmas with magnetic field boundaries     

A.D.R. Phelps 《Planetary and Space Science》1973,21(9):1497-1509

The magnetopause, the boundary layer, or current sheath, which separates the magnetosphere from the solar wind, is the particular interaction considered in this paper.The collision free electron skin depth, $\text{ξ}{}_{\mathrm{e}}\text{=}\text{c}\text{ω}{}_{\mathrm{pe}}$, where c is the velocity of light and ω_pe, is the plasma frequency, gives a classical measure of the penetration depth of a collisionless plasma by an electromagnetic field. This penetration depth is small compared with the dimensions of the magnetosphere and hence the boundary layer may be conveniently considered in one dimension.In General all one dimensional solutions lie within an order of magnitude of the value of ξ_e, the only exception being the important one, in which the electric field perpendicular to the current sheath plane is not present, either due to a particular trapped particle distribution or due to a short circuiting end effect. For this exception the thickness is increased by the factor ($\text{m}{}_{\mathrm{i}}\text{i/m}{}_{\mathrm{e}}\text{)}{}^{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$.The current sheath solutions discussed are equilibrium solutions but not necessarily stable equilibrium solutions.The extension of the models to three dimensions has a larger effect than might at first be expected. The effect may be intuitively understood as a consequence of flux conservation in the sheath. The one dimensional solutions then correspond to the current sheath profiles at the thinnest point of the three dimensional sheath.  相似文献   

贸易保护与知识产权影响下中国电子通信产业参与全球分工的时空演化     

王翔宇  叶玉瑶  Nicholas A.Phelps  吴康敏  黄耿志  王洋  张虹鸥 《地理研究》2021,40(12):3399-3419

中国电子通信产业受国际贸易保护的冲击日趋严重。国际贸易保护与地方知识产权制度通过影响企业参与全球生产网络（GPN）高技术附加值环节,而影响中国电子通信业在全球的分工。制度是衔接演化经济地理与GPN两个范式重要的共有要素,但已有文献对产业演化、制度变迁与GPN动态三者之间的融合缺乏关注,关于超国家制度与区域制度对区域产业嵌入GPN的复杂影响探讨不足。本研究基于2002—2016年间中国的国际贸易和相关制度数据,运用时间序列模型,分析中国电子通信产业嵌入GPN的分工情况对国际贸易保护与地方知识产权制度演变的时间响应;并进一步建立空间收敛模型,对不同区域间这一分工差异进行分析。研究发现,总体而言中国各地区电子通信业在国际分工中的差异未随时间变化而缩小,贸易保护使得区域间电子通信业参与全球分工的差异逐渐扩大,而知识产权制度则有助于缩小区域间的这一差异。具体发现：① 在东部地区,各省份的国际分工差异随时间变化而扩大,而中部地区各省份的差异则在缩小。② 从长期来看,贸易保护制度有助于提升中国整体和东部、中部地区电子通信业在国际上的水平分工度;东部地区对贸易保护制度的响应更快;贸易保护对东部地区在国际分工中位置变动的影响更强。③ 各地区知识产权保护对其产业嵌入GPN分工演化的影响不尽相同,且影响并不显著。研究结果对当前中国电子通信业遭遇贸易保护冲击以及“双循环”战略背景下制定相关政策具有指导意义。当下制定产业发展政策需要因地制宜,考虑各地区电子通信业发展的不同阶段,以实现出口额和产品附加值的双增长。  相似文献   

Centrifuge simulation of the consolidation characteristics of capped marine sediment beds     

Horace Moo-Young  Tommy Myers  Barbara Tardy  Richard Ledbetter  Wipawi Vanadit-Ellis  Tae-Hyung Kim 《Engineering Geology》2003,70(3-4):249-258

Marine sediment capping is a technique where clean sand or sediment is placed over contaminated sediment to reduce the migration of contaminants to the environment. Environmental regulations have limited the use of in situ sediment capping due to concerns about the contaminant migration through the cap. A series of centrifuge tests were conducted to simulate the effects of consolidation settlement of capped marine sediment. This study describes the testing and monitoring of the centrifuge tests. The results from the centrifuge tests are interpreted and compared to predictions made by the PSDDF computer program, which can qualitatively estimate the consolidation settlement of capped marine sediment.

Centrifuge tests were utilized to predict the consolidation of marine sediment caused by the placement of a capping layer. The centrifuge tests used the modeling of models technique to verify that correct modeling procedures were utilized. In this study, the maximum deviation between the centrifuge test results and PSDDF prediction was 20%. Thus, designers should utilize PSDDF consolidation settlement results with caution. Dye tracer studies showed the importance of consolidation-induced advective transport of contaminants. Thus, the capping layer must be appropriately designed to reduce the effects of consolidation-induced advective transport. This may be accomplished by adding a reactive barrier or geosynthetic barrier layer to the cap design.  相似文献