The effect of riparian land use on transport hydraulics in agricultural headwater streams located in northeast Ohio,USA

This study examined if riparian land use (forested vs agricultural) affects hydraulic transport in headwater streams located in an agriculturally fragmented watershed. We identified paired 50‐m reaches (one reach in agricultural land use and the other in forested land use) along three headwater streams in the Upper Sugar Creek Watershed in northeast Ohio, USA (40° 51′42″N, 81° 50′29″W). Using breakthrough curves obtained by Rhodamine WT slug injections and the one‐dimensional transport with inflow and storage model (OTIS), hydraulic transport parameters were obtained for each reach on six different occasions (n = 36). Relative transient storage (A_S:A) was similar between both reach types (As: A = 0·3 ± 0·1 for both agricultural and forested reaches). Comparing values of F_med²⁰⁰ to those in the literature indicates that the effect of transient storage was moderately high in the study streams in the Upper Sugar Creek Watershed. Examining travel times revealed that overall residence time (HRT) and residence time in transient storage (T_STO) were both longer in forested reaches (forested HRT = 19·1 ± 11·5 min and T_STO = 4·0 ± 3·8 min; agricultural HRT = 9·3 ± 5·3 min and T_STO = 1·7 ± 1·4 min). We concluded that the effect of transient storage on solute transport was similar between the forested and agricultural reaches but the forested reaches had a greater potential to retain solutes as a result of longer travel times. Copyright © 2009 John Wiley & Sons, Ltd.     

松软煤系地层深孔绳索取心钻探实践

长春市高家窝棚—双泉眼矿区为松软煤系地层,采用绳索取心液动冲击回转钻进方法,选择加大钻孔孔壁与钻杆环状间隙的钻孔结构;经实验选择以粘土、共聚物、植物胶、铵盐、腐植酸钾、磺化沥青、聚丙烯酸钾等材料配制的冲洗液,并加强冲洗液的日常维护管理;配备离心式除泥机;套管丝扣连接处涂抹松香（粘结剂）,并用薄钢板焊接补强丝扣连接处,防止套管脱扣等技术措施,成功地完成了2个深孔的钻孔施工,终孔深度分别为1112.45 m（ZK6405孔）和1359.95 m（ZK3201孔）,岩心采取率达到100%,煤心样品没有燃烧破坏现象,较好地满足了地质的要求。     

液力衡扭旋冲提速工具及其在达深16井的应用

大庆油田深部地层岩石坚硬、研磨性强,运用常规手段钻进,单只钻头进尺少、寿命短且机械钻速较低。应用液力衡扭矩提速工具,有效解决了这些问题,显著提高了机械钻速和单只钻头的进尺。通过达深16井的现场试验证明,该工具能够使钻头的破岩方式在剪切的基础上附加机械冲击和高压水力脉冲,有效提高PDC钻头剪切岩层的效率,为深井提速提供了一种有效的手段。     

庆深气田深层钻完井配套技术

自庆深气田徐深1井取得深层天然气勘探重大突破以来,大庆油田步入了油气勘探开发并举阶段。2004—2010年完成123口井,平均井深4118 m、钻井周期141 d,钻井技术水平较低。虽然开展提速技术攻关取得一定效果,但仍然不能满足天然气快速增储上产的需求,还存在着固井后井口带压问题,急需深入开展钻完井技术攻关。自2011年起,借鉴国内外深层提速技术成果,分开次、分层段针对岩性特点制定提速对策,通过优化井身结构、优选高效PDC钻头、实验并自研液动旋冲和涡轮等新型提速工具,大幅度提高了深井钻井技术水平,2011—2013年完成19口井,平均井深4075 m、同比缩短钻井周期48.6 d;针对井口带压问题,综合分析其产生因素,开展系列技术研究,形成了防气窜固井配套技术,为深层天然气快速增储上产提供了支持和保障。     

对流参数主分量旋转法在西昌地区雷暴预报中的应用

为研究对流参数主分量旋转方案对西昌地区雷暴预报的影响,利用2006~2008年雨季(6~9月)T213模式输出产品,采用F-分值法和主分量旋转法,分别初选和精选因子,并结合二元Logistic回归分析,建立了西昌北郊某站的雷暴释用预报的模型,并对该站2010年雨季雷暴进行预报试验。试验结果表明:精选因子的KMO检验值在0.65~0.85,且Bartlett球形度检验显著,说明该站的雷暴对流参数适用于因子分析;极大方差旋转能够较好地分离因子载荷,对雷暴信息的提取能力较强;试报的TS评分在0.3左右,24小时预报的Hedike评分可达0.337,模型的预报准确率较高,持续性较好。综上所述,采用主分量旋转法对雷暴的MOS预报有一定的改善效果。     

Effect of hydraulic loading rate on the efficiency of effluent treatment in a recirculating puffer aquaculture system coupled with constructed wetlands

Constructed wetlands(CWs) were integrated into an indoor recirculating aquaculture system of obscure puffer(Takifugu obscurus) for effluent treatment. The effect of hydraulic loading rate(HLR) on the efficiency of effluent treatment by CWs was examined for over a month. The CWs were operated under brackish conditions(salinity 7.4–7.6) at 3 different HLRs(0.762, 0.633, and 0.458 m d–1) 3 times, 10 days each. Overall, the CWs exhibited high efficiency in removal of total ammonium nitrogen(by 81.03–92.81%) and nitrite nitrogen(by 99.40%–99.68%). The efficiency of CWs in removal of total ammonium nitrogen, nitrate nitrogen, total Kjeldahl nitrogen, total phosphorous, and total suspended solids(TSS) increased with the decrease of HLR. The CWs operated at the 3 HLRs in a decreasing trend proves to be effective, providing a useful method for effluent treatment in commercial puffer aquaculture systems.     

导航电子地图多尺度显示与载负量的研究

导航电子地图的多尺度显示目的就是在导航终端有限的屏幕容量下．形成适宜载负量的地图。本文在对导航电子地图载负量指标进行研究的同时,将导航电子地图用于显示的道路形状数据、背景数据、地名数据,按照每一类要素的几何大小或重要程度再分为若干级别,利用分级显示技术,计算出导航电子地图各级显示尺度下的合理载负量,使导航电子地图在多尺度表达时显示要素载负量合理、分布均匀,尺度切换时鼐示要素过渡自然、流畅。     

Effects of anthropogenic disturbance on the abundance and size of epibenthic jellyfish Cassiopea spp

Jellyfish blooms in pelagic systems appear to be increasing on a global scale because of anthropogenic impacts, but much less is known about the link between human activities and epibenthic jellyfish abundance. The aim of this study was to investigate whether the epibenthic jellyfish, Cassiopea spp., were found in greater abundance, and attained larger sizes, in coastal habitats adjacent to high human population densities compared to sites adjacent to uninhabited areas on Abaco Island, Bahamas. Cassiopea spp. were found to be significantly more dense and larger in areas with high human population densities. Ambient nutrient levels and nutrient content of seagrass were elevated in high human population density sites, and may be one mechanism driving higher abundance and size of Cassiopea spp. Cassiopea spp. may have important effects on community structure and ecosystem function in critical coastal ecosystems (e.g., seagrass beds), and their impacts warrant further study.     

Transient dynamic response of fluid-saturated soil under a moving cyclic loading

Based on the Theory of Porous Media (TPM), a mathematical model of a two-dimensional incompressible fluid-saturated elastic soil is established, and the periodic boundary conditions are presented to analyze the transient dynamic response of this soil under a moving cyclic loading. The differential quadrature method (DQM) and the second-order backward difference scheme are applied to discretize the governing equations on the spatial and temporal domains, respectively. As application, a typical two-dimensional wave-induced transient problem with a seabed of finite thickness is analyzed, and the numerical results are compared with the analytical results presented in the present work. In addition, a transient dynamic response of fluid-saturated soil under limit moving vehicle loadings is studied. The effects of the velocity of vehicle and the volume fraction on the settlement and the pore water pressure are studied.     

内圆外方复合钢管混凝土短柱轴压承载力试验研究

为研究内圆外方复合钢管混凝土柱的轴压承载力,完成了10个试件的轴心受压试验。试验结果表明:达到峰值承载力时,方钢管纵向已屈服、横向尚未屈服;试件的破坏形态为方钢管向外鼓曲、沿纵向局部撕裂,方钢管与圆钢管之间的混凝土已经酥松、局部压碎;大部分试件即使纵向平均压应变达到0.11,尚能承担不小于其峰值承载力70%的轴力;压缩刚度的计算值平均为实测值的83.6%。采用钢管仅提供轴压承载力、不提供横向约束的假定计算得到的试件的轴压承载力,与试验结果符合最好。