Improved spatial delineation of streambed properties and water fluxes using distributed temperature sensing          下载免费PDF全文

Landon J. S. Halloran  Hamid Roshan  Gabriel C. Rau  Martin S. Andersen  R. Ian Acworth 《水文研究》2016,30(15):2686-2702

A new method was developed for analysing and delineating streambed water fluxes, flow conditions and hydraulic properties using coiled fibre‐optic distributed temperature sensing or closely spaced discrete temperature sensors. This method allows for a thorough treatment of the spatial information embedded in temperature data by creating a matrix visualization of all possible sensor pairs. Application of the method to a 5‐day field dataset reveals the complexity of shallow streambed thermal regimes. To understand how velocity estimates are affected by violations of assumptions of one‐dimensional, saturated, homogeneous flow and to aid in the interpretation of field observations, the method was also applied to temperature data generated by numerical models of common field conditions: horizontal layering, presence of lateral flow and variable streambed saturation. The results show that each condition creates a distinct signature visible in the triangular matrices. The matrices are used to perform a comparison of the behaviour of one‐dimensional analytical heat‐tracing models. The results show that the amplitude ratio‐based method of velocity calculation leads to the most reliable estimates. The minimum sensor spacing required to obtain reliable velocity estimates with discrete sensors is also investigated using field data. The developed method will aid future heat‐tracing studies by providing a technique for visualizing and comparing results from fibre‐optic distributed temperature sensing installations and testing the robustness of analytical heat‐tracing models. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

A shift towards wetter and windier conditions in southern Sweden around the prominent solar minimum 2750 cal a BP          下载免费PDF全文

ANETTE MELLSTRÖM  NATHALIE VAN DER PUTTEN  RAIMUND MUSCHELER  RIXT DE JONG  SVANTE BJÖRCK 《第四纪科学杂志》2015,30(3):235-244

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A Methodology for Clustering Lakes in Alberta on the basis of Water Quality Parameters     

Tahir Ali Akbar  Quazi K. Hassan  Gopal Achari 《洁净——土壤、空气、水》2011,39(10):916-924

In this study, a methodology for clustering 18 lakes in Alberta, Canada using the data of 19 water quality parameters for a period of 11 years (1988–2002) is presented. The methods consist of (i) principal component analysis (PCA) to determine the dominant water quality parameters, (ii) cluster analysis techniques to develop the characteristics of the clusters, and (iii) pattern‐match lakes to determine the appropriate cluster for each of the lakes. The PCA revealed that three principal components (PCs) were able to explain ～88% of the variability and the dominant water quality parameters were total dissolved solids, total phosphorus, and chlorophyll‐a. We obtained five clusters for the period 1994–1997 by using the dominant parameters with water quality deteriorating as the cluster number increased from 1 to 5. Upon matching cluster patterns with the entire dataset, it was observed that some of the lakes belonged to the same cluster all the time (e.g., cluster 1 for lakes Elkwater, Gregg, and Jarvis; cluster 3 for Sturgeon; cluster 4 for Moonshine; and cluster 5 for Saskatoon), while others changed with time. This methodology could be applied in other regions of the world to identify the most suitable source waters and prioritize their management. It could be helpful to analyze the natural controlling processes, pollution types, impact of seasonal changes and overall quality of source waters. This methodology could be used for monitoring water bodies in a cost effective and efficient way by sampling only less number of dominant parameters instead of using a large set of parameters.  相似文献   

碳纤维加固技术在水利工程中的应用研究     

王怀国  秦英才 《地下水》2011,(1):165-167

针对王铺渡槽上部墩柱结构出现的大开度贯穿性裂缝,课题组经过全面分析和多方案综合对比,采用裂缝化灌、碳纤维加固、外表面刷涂水性环保型乳胶漆外墙涂料作为防护的综合措施对原工程进行有效的加固处理,并结合水利工程的自身特点改进了加固技术工艺,取得了显著的经济和社会效益.  相似文献   

示波极谱法测量电锌液中微量镍   总被引：1，自引：0，他引：1  

杨毅  黄晓林 《云南地质》2011,30(1):105-106

提出在丁二酮肟-亚硝酸钠-氨水-氯化铵体系中,准确测定电锌液中微量镍的新方法:克服原子吸收光谱法测定微量镍回收率偏低问题。  相似文献   

缅甸莫苇塘红土型镍矿矿物学特征     

吕建中  朱永平  郎学君  杨永刚 《云南地质》2011,30(2):193-197

莫苇塘红土型镍矿分为土状矿和岩状矿,矿物成分基本相同,但量上有差异。矿石主要由蛇纹石类硅酸盐矿物和褐铁矿、赤铁矿等氧化物、氢氧化物矿物组成,有用组份镍主要赋存于硅酸盐类矿物和氧化物、氢氧化物类矿物中。  相似文献   

新疆坡十铜镍硫化物含矿岩体岩浆源区特征及构造背景探讨   总被引：7，自引：1，他引：6       下载免费PDF全文

颉炜  宋谢炎  聂晓勇  程松林 《地学前缘》2011,18(3):189-200

新疆坡北辉长岩体位于塔里木古陆东北缘的北山裂谷带中,坡一和坡十铜镍硫化物含矿超镁铁岩体位于坡北岩体内.尽管坡十超镁铁岩体与坡北辉长岩呈侵入接触,但两者的微量元素和同位素组成显示良好 的一致性,表明两岩相虽然分不同阶段侵入就位,但仍为同源岩浆的产物.MnO-TiO2-R2O5及Th-Hf-Ta判别图解显示坡北及坡十岩体的...  相似文献   

桩端加环对PHC桩影响的试验研究     

陈亮 《岩土工程技术》2011,25(1):5-9,37

PHC桩在动力打桩过程中,往往会因为锤击数或锤击能量过高而发生桩头或桩身损坏,引起的挤土效应和振动效应也会对周围环境造成不良影响.PHC桩桩端加环可减少沉桩过程中桩侧土体摩阻力的影响,结合某电厂工程综合试桩工作,通过对沉桩总锤击数、最终贯入度、土塞高度、打桩振动测试及高应变检测结果的分析,指出桩端加环对保证PHC桩的完...  相似文献   

2008年夏季西北冰洋观测区叶绿素a和初级生产力粒级结构          下载免费PDF全文

刘子琳  陈建芳  刘艳岚  白有成  张海生  高生泉  李宏亮  卢勇 《海洋学报》2011,33(2):124-133

对2008年夏季在西北冰洋172°～143.6°W的楚科奇海及其北部海区对粒度分级叶绿素a和初级生产力现场观测资料,对观测区的空间分布特征进行了研究.结果表明,观测海区表层叶绿素a浓度为0.013～19.367 μg/dm3,平均值为0.677士2.2661 μg/dm3,次表层水叶绿素a浓度高于其它水层.水柱叶绿素a...  相似文献   

小秦岭车仓峪钼矿成因研究:辉钼矿Re-Os年龄及黄铁矿微量元素制约     

赵海香  戴宝章  李斌  朱志勇 《岩石学报》2015,31(3):784-790

车仓峪钼矿位于小秦岭中生代娘娘山花岗岩体与太华群基底的接触带内,矿体发育在由一组X节理控制的石英脉内。本文对车仓峪钼矿开展了辉钼矿Re-Os定年以及黄铁矿微量元素LA-ICP-MS原位分析工作。所得辉钼矿Re-Os模式年龄为133.8±4.3Ma和132.7±2.2Ma,表明车仓峪钼矿的成矿年龄为早白垩世,与娘娘山岩体的成岩年龄一致。辉钼矿样品的Re含量较低,为83×10-6和86×10-6,指示了成矿物质可能来源于I型花岗岩——娘娘山花岗岩。对与辉钼矿共生的黄铁矿进行LA-ICP-MS微量元素原位分析,发现黄铁矿中Ni含量低(4.5×10-6~76.1×10-6,平均17.4×10-6),表明其来源应该是酸性岩,也就是其围岩娘娘山花岗岩。综合辉钼矿定年以及黄铁矿微量元素分析结果,车仓峪钼矿应该是早白垩世娘娘山花岗岩侵位时,由岩浆冷凝分异出的成矿流体充填和交代围岩形成。同时,小秦岭燕山期Mo矿化并不伴随Au矿化,结合已有资料,从侧面说明燕山期可能并不是小秦岭金的主成矿期。  相似文献