Application of multivariate statistical techniques in assessment of surface water quality in Second Songhua River basin,China

Multivariate statistical techniques,such as cluster analysis(CA),discriminant analysis(DA),principal component analysis(PCA) and factor analysis(FA),were applied to evaluate and interpret the surface water quality data sets of the Second Songhua River(SSHR) basin in China,obtained during two years(2012-2013) of monitoring of 10 physicochemical parameters at 15 different sites.The results showed that most of physicochemical parameters varied significantly among the sampling sites.Three significant groups,highly polluted(HP),moderately polluted(MP) and less polluted(LP),of sampling sites were obtained through Hierarchical agglomerative CA on the basis of similarity of water quality characteristics.DA identified p H,F,DO,NH3-N,COD and VPhs were the most important parameters contributing to spatial variations of surface water quality.However,DA did not give a considerable data reduction(40% reduction).PCA/FA resulted in three,three and four latent factors explaining 70%,62% and 71% of the total variance in water quality data sets of HP,MP and LP regions,respectively.FA revealed that the SSHR water chemistry was strongly affected by anthropogenic activities(point sources:industrial effluents and wastewater treatment plants;non-point sources:domestic sewage,livestock operations and agricultural activities) and natural processes(seasonal effect,and natural inputs).PCA/FA in the whole basin showed the best results for data reduction because it used only two parameters(about 80% reduction) as the most important parameters to explain 72% of the data variation.Thus,this work illustrated the utility of multivariate statistical techniques for analysis and interpretation of datasets and,in water quality assessment,identification of pollution sources/factors and understanding spatial variations in water quality for effective stream water quality management.

Perturbation Analysis of the Attached Water Mass Effect on Offshore Platform Dynamic Response

Theoretically speaking, it is impossible to make the differential equation of motion uncoupled for the natural modes of a system in consideration of the attached water. The hydro-elastic structure is equal to the non-proportional damping system. In this paper a perturbation analysis method is put forward. The structure motion equation is strictly solved mathematically, and the non-proportional damping problem is transformed into a series of proportional damping ones in the superposition form. The paper also presents the calculation formula of the dynamic response of the structure being subjected to harmonic and arbitrary load. The convergence of the proposed method is also studied in this paper, and the corresponding convergence conditions are given. Finally, the proposed method is used to analyze the displacement response of a real offshore platform. The calculation results show that this method has the characteristics of high accuracy and fast convergence.

Assessment of water resources in Yarmouk River Basin using geospatial technique during the period 1980–2020

It is common knowledge that Yarmouk River Basin(YRB)is shared between Jordan and Syria.Management of YRB trans-boundary water resources is attracting increasing interest because it is a strategic water resource for the riparian countries.Actually,lack of sharing information regarding hydrological flows and basin’s water management between partners’countries makes it difficult to distinguish between natural and man-made factors affecting the water body.Therefore,this study seeks to address and assess the main on-site changes that exert on YRB.Geospatial technique and arithmetic equations were combined to carry out an assessment of the changes on water resources in YRB.Data,information and field measurements of the basin were aggregated,compiled and presented to determine the extent of changes during the period 1980-2020.Remarkable findings showed that precipitation amount in the basin significantly declined during the period 1980-2020 in particularly after the year 1992.Pumping rate of groundwater was 550 x 103 m3/a,exceeding the basin’s safe yield.Draw down of static groundwater level over time approached the value of-3.2 m/a due to the over abstraction in the aquifer body.Additionally,the evaporation rate reached more than 99%in some regions in the basin.Moreover,the number of private wells has increased from 98 wells in 1980 to 126 wells in 2020,showing the excessive extraction of groundwater.These findings indicate that the study area is subjected to a considerable groundwater depletion in the near future due to extensive abstraction,continuous drilling of illegal wells and decreased annual precipitation under the shadow of the rapid population growth and continuous influx of refugees.Therefore,decision makers-informed scenarios are suggested in the development of water resource portfolios,which involves the combination of management and infrastructural actions that enhance the water productivity of the basin.Further studies are recommended to evaluate the on-site changes on water resources in YRB in collaboration with riparian countries and to establish monitoring system for continuous and accurate measurements of the basin.

Water Quality Monitoring of the Bezerra River （Cascavel, Brazil） Using SR-TXRF Technique

The present study aims to monitor and assess the water quality of the Bezerra River located in the Western Brazilian Parana state. For the monitoring of river waters, six samplings were established per month during one year. As indicators of the water quality, physico-chemical parameters such as water temperature, pH, turbidity, dissolved oxygen and COD （chemical oxygen demand） were chosen, as well as trace and majority element concentrations. It is noteworthy that the mean annual values of conductivity, turbidity and COD have progressively increased along the river with maximum values after the Cascavel western sewage treatment plant. Only 13 elements were found in the six collection points, but the metallic elements Cr, Mn, Fe, Cu and Zn have shown concentrations above the maximum limits recommended by Brazilian environmental legislation, suggesting the presence of highly polluting anthropogenic sources. Correlation analyses were used to determine the spatio-variability of water quality variables. The six collection sites were grouped into two clusters, with the element composition in the first cluster （sites 1, 2 and 6） being due to strong anthropogenic activities. The study of the Bezerra River water quality could help to develop municipal environmental policies and help with the management of water conservation in the Bezerra River basin.

基于广义积分变换法海洋温差能大口径冷水管强迫振动分析

复杂多变的海洋工况将诱发大口径冷水管强迫振动,为探明均布载荷、线性变化的静水压力、集中载荷和周期载荷作用下冷水管振动响应机制。基于Euler-Bernoulli梁理论,建立了管道动力学控制方程,采用广义积分变换法,求解了系统强迫振动的解析解,并与同伦摄动法相对比,验证了该方法的高精度和有效性,分析了内流、黏弹性耗散系数、阻尼比和质量比对管道振动特性的影响。结果表明:当内流流速对应的振动频率与固有频率接近时,管道将出现动态失稳。增大黏弹性耗散系数、阻尼比和质量比对横向位移的抑制效果呈现依次递减的规律,改变激振位置和激振频率可显著改变管道横向位移。该研究成果可对冷水管的初期设计提供一定的指导作用。

玫瑰水芳香成分的分析测定及应用研究进展

玫瑰水,又称玫瑰纯露、玫瑰蒸馏水、玫瑰水精油等,是提取玫瑰精油时产生的副产品,是一种安全、无毒、透明的水溶液。玫瑰水具有美白、保湿、抗氧化、抗菌、抵御紫外线等多重功效,是香水、化妆品、食品、制药等领域的重要原料。玫瑰水中的各种挥发性成分组成了玫瑰水的天然芬芳,在全球广受喜爱。然而,目前我国尚无玫瑰水质量控制的国家标准,市售产品质量参差不齐。本文对玫瑰水的主要芳香成分进行了梳理,总结了目前国内外玫瑰水的前处理技术,分析测定方法及相关应用,并对玫瑰水产业发展趋势进行了展望,以期为该领域相关人员提供有益参考。

GT-GRA-TOPSIS在雨水调蓄池选址及数量优化中的应用

【目的】为有效减轻极端暴雨天气造成的城市洪涝问题,开展了对城市雨水排水系统(USDS)中雨水调蓄池(SST)的选址及数量优化的研究。【方法】采用博弈论(GT)思想将层次分析法(AHP)获得的主观权重与改进熵值法(IEVM)获得的客观权重组合赋权,并与灰色关联分析(GRA)和逼近理想解排序(TOPSIS)相结合,建立了城市内涝与面源污染风险的定量评估框架。根据各节点的相对接近度确定风险等级,风险较高的节点设置SST,根据积水削减率和总悬浮物(TSS)削减率优化SST的数量。以山西省长治市为例,探讨了该方法在不同降雨重现期时城市内涝和面源污染的控制效果。【结果】GRA-TOPSIS法在5 a和10 a降雨重现期时的综合变异系数分别为0.355和0.361,极值均为0.496,均高于单独GRA或TOPSIS.【结论】GT赋权并耦合GRA-TOPSIS的优化方法采用较少的经济投资可较好地消除城市内涝和面源污染风险,为SST的选址和数量优化提供了新思路。

水环境重金属分析检测技术研究

本文对水环境中重金属分析检测技术进行研究,首先阐述了水环境中重金属的基本定义与类型,分析了重金属污染的特征,如处理难度大、恢复成本高。其次根据本文的核心模块,探讨了电化学法、光谱法、生物化学法、液相色谱法等检测技术,并明确了各类检测技术在应用中的优缺点、注意事项等。通过对实践应用实例进行分析,验证了重金属分析检测技术的使用效果和准确度等。最终得出结论:重金属分析检测技术的灵活应用可为水环境检测提供更大的便利性,对维持水环境在较高水平上具有一定促进作用。

基于多种方法的信阳市水资源系统韧性评价

随着经济社会的发展,水资源系统面临的风险日益严重,探究水资源系统韧性对合理利用水资源、促进水资源可持续发展具有重要意义。根据信阳市水资源实际情况,从抵抗性、恢复性、适应性层面选取18个指标确立信阳市水资源系统韧性评价指标体系,基于熵权法确定各评价指标权重,采用模糊综合评价法、灰关联分析法、TOPSIS法,分别从评价对象的优劣等级、评价对象与最优方案之间关联度和评价对象与最优方案的接近程度等3个方面对信阳市2012—2021年的水资源系统韧性展开评价。结果表明:模糊综合评价法能更好地界定水资源系统韧性的评价标准;基于模糊综合评价法,2012—2021年信阳市水资源系统韧性水平主要为等级Ⅱ和Ⅲ,变化趋势总体是上升的,但仍存在提升的空间。

Estimations of Precipitable Water and Its Characteristics during the HUBEX/IOP 1998

GMS-5 satellite data at channels of infrared split windows and water vapor are analyzed to retrieve the precipitable water (PW) distributions under cloud-free conditions. Radiosonde data and surface station data are applied to estimate the PW distributions under cloudy conditions. These two methods are then merged to obtain the PW distributions under all-weather conditions during the Huaihe River Basin Energy and Water Cycle Experiment (HUBEX). The results of the all-weather PW distributions from these methods demonstrate that this new merging technique may be applied to derive large-scale or global maps of PW. It is revealed that the atmospheric water vapor over the Yangtze-Huaihe River Basins came mainly from the southwest during the 1998 prevailing period of Meiyu. Sufficient atmospheric PW is a necessary condition for ground rainfall. Under certain dynamic conditions, it can be partially transformed into surface precipitation. Several types of rain are displayed and their PW conditions and characteristics, as well as atmospheric dynamic conditions, are analyzed. It is demonstrated that surface precipitation centers usually appear not at the high PW centers but on their downwind sides.

基于博弈论赋权耦合灰色关联分析的调蓄池优化选址

在构建城市内涝风险评估指标体系的基础上,采用博弈论(GT)思想将层次分析法(AHP)所得主观权重与改进熵值法(IEVM)所得客观权重组合赋权,并将灰色关联分析(GRA)与逼近理想解排序(TOPSIS)相结合,建立量化评估框架,最终通过各节点的相对贴近度确定调蓄池的位置。结果表明:GRA-TOPSIS所得综合值的变异系数为0.628,均高于单独使用GRA或TOPSIS的变异系数,更有利于对各节点内涝风险进行辨识。此外,应用该方法对消除城市内涝风险、提高城市防涝标准有显著效果。

A critical review of on-site inorganic arsenic screening methods

Approximately 94 to 220 million people worldwide are at risk of drinking well water containing arsenic > 10 μg/L, the WHO guideline value. To identify non-compliant domestic wells, assess health risks and reduce exposure, accurate and rapid on-site inorganic arsenic screening methods are desirable because all domestic wells worldwide need to be tested.Here, the principles, advantages and limitations of commonly used colorimetry, electrochemistry, and biosensing methods are critically reviewed, with the performance compared with laboratory-based benchmark methods. Most commercial kits are based on the classic Gutzeit reaction. Despite being semi-quantitative, the more recent and more expensive products display improved and acceptable accuracy and shorter testing time (~10 min). Carried out by trained professionals, electrochemical methods are also feasible for on-site analysis, although miniaturization is desirable yet challenging. Biosensing using whole bacterial cells or bio-engineered materials such as aptamers is promising, if incorporated with function specific nanomaterials and biomaterials. Since arsenic is frequently found as arsenite in reducing groundwater and subject to oxidation during sampling, transportation and storage, on-site separation and sample preservation are feasible but the specific methods should be chosen based on sample matrix and tested before use. To eliminate arsenic exposure among hundreds of millions of mostly rural residents worldwide, we call for concerted efforts in research community and regulatory authority to develop accurate, rapid, and affordable tests for on-site screening and monitoring of arsenic in drinking water. Access to affordable testing will benefit people who are socioeconomically disadvantaged.

地下水流影响下含盐饱和粉砂地层中联络通道冻结温度场的特征分析

随着城市地下空间的快速发展,人工冻结法已经广泛应用于地铁联络通道的施工过程,但针对含盐粉砂层中的联络通道冻结法在地下水流作用下的机理尚不明确,导致原计划冻结时间的延长.以人工冻结法为研究背景,提出了冻结过程中水流-盐分共同作用下的耦合分析方法.首先,基于多孔介质传热、Darcy定律和Fick定律,建立了水-热-盐三场耦合的物理数学方程;然后,利用有限元软件COMSOL Multiphysics模拟含盐土体的冻结模型试验,并与模型试验结果进行对比分析,验证了本方法的有效性;最后,将本方法应用于南通地铁1号线永兴大道站|深南路站区间4#联络通道冻结法施工过程模拟,并相应开发了一套多物理场数据监测设备,将模拟结果与监测数据进行对比分析.结果表明,含盐土体比不含盐土体降温更慢,盐分浓度越大,降低同样温度所需时间越长;水头差导致冻结壁呈非对称状,上游冻结壁厚度小于下游冻结壁厚度;通过对冻结壁厚度和平均温度的计算,模拟冻结45 d达不到设计要求,需要冻结50 d.保证了南通地铁1号线联络通道人工冻结法施工的安全,并提供了一种在复杂环境条件下冻结施工的多场耦合分析方法.

吹扫捕集/气相色谱-同位素比值质谱联用测定水体中痕量苯系物单体碳同位素

建立了吹扫捕集(P&T)/气相色谱-同位素比值质谱(GC/C-IRMS)联用测定水体中痕量苯系物单体碳同位素的方法。优化了吹扫时间、吹扫温度和干吹时间,确定最优吹扫捕集效率,并通过测试不同质量浓度的苯系物水溶液,计算水体中痕量苯系物的检出限。结果表明,在35℃下吹扫捕集13 min,干吹时间3 min条件下,水样中苯、甲苯、乙苯、间/对二甲苯、邻二甲苯、苯乙烯、异丙苯的吹扫捕集效率分别为95.0%、90.2%、71.3%、59.1%、69.4%、50.8%和70.1%,7种苯系物单体碳同位素的标准偏差(STD)为0.06‰~0.29‰。7种苯系物的质量浓度在0.50~20.00μg/L范围内与峰面积的线性关系良好,相关系数(r2)为0.998 6~0.999 5,在各浓度下7种苯系物单体碳同位素值的标准偏差为0.090‰~0.48‰,进样量及进样方式的差异不会导致碳同位素分馏。水样中苯、甲苯、间/对二甲苯、邻二甲苯和苯乙烯的检出限为1.00μg/L,乙苯和异丙苯为0.50μg/L。该方法可以极大提高水体中苯系物单体碳同位素的检出限,结果准确可靠,满足水体中痕量苯系物单体碳同位素分析的需求。

水利水电工程地质勘测的方法与技术应用分析

在过去十几年间,我国经济得到了进一步发展,经济规模也越来越大,有效促进了我国基础设施工程领域发展。其中就包括水利水电工程项目。考虑到水利水电工程项目与经济发展及人民群众日常生活息息相关,因此,水利水电工程项目施工得到了我国各地方政府的高度重视。在水利水电工程项目施工过程中,地质勘测工作扮演着举足轻重的角色,不仅仅影响着工程项目设计工作环节,同时也在很大程度上决定了工程项目整体施工质量是否能够达到当地的施工标准。因此,我国建设公司应该对水利水电工程施工中地质勘测技术与方式进行合理选择和应用。笔者在此从现阶段我国水利水电工程项目施工实际情况出发,对提升水利水电工程中地质勘测工作成效进行充分探究,并且在此基础上给出了具有针对性的意见,以期作为同类研究和水利水电工程施工中地质勘测工作实践的参考和借鉴,从而进一步促进我国水利水电工程领域的长期与健康发展。

密云水库三维水质模拟技术

通过水平层面间线性插值计算,模拟密云水库污染质的三维分布。给出水质模拟的3种技术方案:通过着色创建污染质浓度分布的连续图谱,自由设定浓度区间按级差着色的级差分布图谱,创建污染质浓度分布的地图式彩色数字文本浓度分布表。提供基于Windows平台上的数据共享支持。

农田土壤水分和盐分的空间变异性及其协同克立格估值

通过对一块面积为 1hm2 麦田内的 98个观测点取样分析 ,测定了两个时期的土壤水分和盐分含量。结果表明两个时期的土壤含水量均服从正态分布 ,底层盐分均服从对数正态分布 ,而表层的盐分分布具有不确定性。两个时期土壤水分和盐分的变异系数分别属于弱变异和中等变异强度。通过结构分析 ,发现两个时期的水分和盐分均在一定范围内存在空间相关性。对两个时期土壤水分和盐分空间分布的动态变化进行了比较 ,同时采用CoKriging方法进行估值 ,与Kriging法相比 ,其估计方差减少百分数最大达到了 1 36 3%。

现场水分析技术及其在东方气田高温高压气井中的应用

在高温高压气井钻井作业中,钻井液体系调整较频繁且调整范围大、侵入地层较深,导致电缆测试样品的流体性质和侵入地层的钻井液滤液组成比例难以准确判断,为此探索了一种新的现场水分析技术,并在莺歌海盆地东方气田高温高压气井中取得了良好的应用效果。应用本文提出的现场水分析技术,可以快速准确地定量分析电缆测试储层流体中的钻井液滤液和地层水的组成比例,计算储层中流体的总矿化度,进而有助于定性识别流体性质,指导现场测试取样作业,为作业者提供快捷的决策依据。

微震监测技术在矿井水害防治中的研究进展

微震监测技术在矿井水害防治和预测预报中,已成为不可或缺的一种技术手段,对于确保矿山安全生产发挥了重要作用。微震监测技术作为一种间接、无损、实时、连续的地球物理方法,已经被写入《煤矿防治水细则》(2018版)。首先阐述了微震监测技术在矿井水害防治中的应用原理;然后讨论了微震探查地下水强径流带、导水通道(裂隙、断层和陷落柱)、突水通道、浆液扩散过程和采空区未知水体突水的可行性及预测预报规律,通过将人工扰动(如井下钻孔放水、注浆、采掘等)过程中产生的微震事件与音频电透视、瞬变电磁、应力场、瓦斯监测、钻屑量、声电磁、渗流、岩石损伤等场理论进行多场耦合分析和相互验证,分析了对矿井水害进行主动监测和预测预报的可行性;最后对现阶段微震监测技术在矿井水害防治方面的优势和局限性进行了分析,认为科学布置监测网络,优化定位算法,准确分析煤、岩、水活动规律,实现多场耦合,研究煤岩体微震活动性前兆规律,是微震监测技术在矿井水害防治领域的应用研究趋势。

给水管网故障实时诊断方法

本文提出了城市给水管网故障实时诊断的一个快速、有效和实用方法 .方法通过实时监测给水管网中 3个位置的水压变化 ,利用人工神经网络技术来诊断故障位置、故障程度和故障影响范围 .方法可适用于我国北方冬季严寒气候等常常导致的给水管网爆管事故及日常故障的实时诊断 .作为给水管网故障诊断的重要内容之一 ,本文还建立了给水管网局部破坏状态下水力分析的方法 .最后 ,本文以一小型给水管网为例对方法进行了验证 ,并就实际应用中的几个问题进行了讨论 .