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381.
Gregory M. Clark Robert E. Broshears Richard P. Hooper Donald A. Goolsby 《Journal of the American Water Resources Association》2002,38(3):803-818
ABSTRACT: Chemical variability in the Mississippi River during water years 1989 to 1998 was evaluated using stream discharge and water‐quality data in conjunction with the DAFLOW/BLTM hydraulic model. Model simulations were used to identify subbasin contributions of water and chemical constituents to the Mississippi River upstream from its confluence with the Ohio and the Mississippi River and at the Atchafalaya Diversion in Louisiana. Concentrations of dissolved solids, sodium, and sulfate at the Thebes site showed a general decreasing trend, and concentrations of silica and nitrate showed a general increasing trend as the percentage of discharge from the Mississippi River upstream from Grafton increased. Concentrations of most chemical constituents in the Mississippi River at the Atchafalaya Diversion exhibited a decreasing trend as the percentage of water from the Ohio River increased. Regression models were used to evaluate the importance of the source of water to the water chemistry in the Mississippi River at Thebes and the Atchafalaya Diversion. The addition of terms in regression equations to account for the percent of water from sub‐basins improved coefficients of determination for predicting chemical concentrations by as much as nine percent at the Thebes site and by as much as 48 percent at the Atchafalaya Diversion site. The addition of source‐water terms to regression equations increased the estimated annual loads of nitrate and silica delivered from the Mississippi River Basin to the Gulf of Mexico by as much as 14 and 13 percent, respectively. 相似文献
382.
阐述了新型SXD水力旋流沉淀器的工作原理及结构特点,并从理论和实际应用两方面分析了影响水力旋流器处理效果的因素,评价了其在精对苯二甲酸废水处理中的性能。 相似文献
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Vikram M. Vyas Saichiu N. Tong Christopher Uchrin Panos G. Georgopoulos Gail P. Carter 《Journal of the American Water Resources Association》2004,40(1):187-195
ABSTRACT: The Kirkwood‐Cohansey aquifer has been identified as a critical source for meeting existing and expected water supply needs for southern New Jersey. Several contaminated sites exist in the region; their impact on the aquifer has to be evaluated using ground water flow and transport models. Ground water modeling depends on availability of measured hydrogeologic data (e.g., hydraulic conductivity, for parameterization of the modeling runs). However, field measurements of such critical data have inadequate spatial density, and their locations are often clustered. The goal of this study was to research, compile, and geocode existing data, then use geostatistics and advanced mapping methods to develop a map of horizontal hydraulic conductivity for the Kirkwood‐Cohansey aquifer. Spatial interpolation of horizontal hydraulic conductivity measurements was performed using the Bayesian Maximum Entropy (BME) Method implemented in the BMELib code library. This involved the integration of actual measurements with soft information on likely ranges of hydraulic conductivity at a given location to obtain estimate maps. The estimation error variance maps provide an insight into the uncertainty associated with the estimates, and indicate areas where more information on hydraulic conductivity is required. 相似文献
385.
Michael F. Merigliano 《Journal of the American Water Resources Association》1997,33(6):1327-1336
ABSTRACT: The at-a-station hydraulic geometry of stream channels can serve as a predictor of alluvial stream channel behavior. This geometry is the empirical relations describing changes in water surface width, mean depth, and mean velocity with changing discharge. The exponent values are correlated with channel morphology and behavior such as scour and fill, flow resistance, bank resistance, and competence. Channel behavior and morphology are apparently related, but some causes for effects are uncertain. Several studies, using empirical and theoretical bases, are reviewed here to illustrate the relation between hydraulic geometry and channel behavior, but the relations are not always consistent. Hydraulic geometry variables are easy to measure and readily available, but they do not always reflect what may be more important ones such as turbulence, the velocity distribution profile, and distribution and cohesion of sediment particles. This paper illustrates some of these problems, provides some solutions, and addresses need for more work to better predict stream channel behavior from hydraulic geometry 相似文献
386.
采用硬化河道水力跌水复氧小试装置,研究了跌水高度、跌水流量、跌水深度、进水DO浓度等因素对硬化河道水力跌水复氧效果的影响。试验结果表明,跌水高度为0.6 m条件下水力跌水对硬化河道水体的复氧效果,优于跌水高度为0.2 m和0.4 m时的复氧效果;跌水流量为150 L/h条件下水力跌水复氧效果,优于跌水流量为50 L/h和100 L/h时的复氧效果;跌水深度为0.4 m条件下水力跌水复氧效果优于跌水深度为0.2 m时的复氧效果。水力跌水措施对硬化河道水体的复氧效果整体上与跌水高度、跌水流量、跌水深度呈正相关,与进水DO浓度呈负相关。 相似文献
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本文介绍了二氧化碳致裂技术的主要装置特点及其工作原理,并以152掘进巷道作为主要的研究对象,针对巷道的掘进消突中二氧化碳致裂技术的应用进行探讨。结果表明:基于二氧化碳气体相变原理致裂爆破技术方式,在致裂期间不会产生火花,同时具有运输安全和操作方便等优点,有利于降低安全风险,提升煤矿的安全生产水平。 相似文献