基于光纤微弯损耗的垃圾填埋场渗漏定位研究

提出了基于光纤微弯损耗原理和光时域反射OTDR技术,针对新型无黏土层危险废物填埋场渗漏检测的定位方法。由于渗漏的垃圾渗滤液会使膨润土防水毯(GCL)膨胀,导致与之紧贴的光纤发生弯曲变形,激光束通过弯曲的光纤会出现光能损耗,通过测量后向瑞利散射光的功率,即可实现对光纤沿程的弯曲情况进行检测,结合光时域反射原理对出现弯曲损耗的故障点进行定位。建立了填埋场渗漏检测的数学模型,利用理论推导和实验研究证实了该方法的可行性。实测结果表明:防渗膜破损位置与测量结果高度吻合,最大定位误差为1.4 m,最大定位引用误差为0.133%。     

分岔隧道火灾烟气流动特性研究*

为探究分岔隧道烟气流动特性,采用CFD数值仿真技术,选取3个火源位置、5个热释放速率,模拟分析顶棚最大温升、主隧道及岔道内顶棚下方温度纵向衰减规律。结果表明:火源位置对顶棚下火源正上方最大温度影响较小,最大温差约为34 ℃,但对火源附近温度影响较大,其中距火源0.5 m处最大温差约为110 ℃;通过对比Hu等和Gong等的预测模型在岔道内顶棚下温度纵向衰减上的拟合曲线可知,Gong等的模型准确性更高;主隧道内上、下游顶棚下温度纵向衰减呈现出不同程度的“反超现象”,且随火源位置逐渐移向岔道内时,“反超现象”逐渐滞后。     

中压燃气管道泄漏工况下流量扰动幅度模拟分析*

为检测和定位燃气管道泄漏,基于泄漏定位公式,利用模拟软件Pipeline Studio构建等效中压管道模型,模拟不同工况条件下燃气管道泄漏动态。结果表明:泄漏发生后,一定时域内用户端流量将出现扰动,供气压力越高、供气量越大、泄漏孔径越小、管道长度越长,流量扰动持续时间越长;忽略管长影响,泄漏位置越接近气源,流量扰动幅度越易出现先增大后减小趋势,反之易出现单调递减趋势;泄漏端位置距离用户端越近,流量扰动幅度越大,反之越小。研究结果可为燃气管道泄漏检测和定位提供理论依据。     

Oviposition height increases parasitism success by the robber fly Mallophora ruficauda (Diptera: Asilidae)

For parasitoids, host finding is a central problem that has been solved through a variety of behavioural mechanisms. Among species in which females do not make direct contact with hosts, as is the case for many dipteran parasitoids, eggs must be laid in an appropriate part of the host habitat. The asilid fly Mallophora ruficauda lays eggs in clusters on tall vegetation. Upon eclosion, pollen-sized larvae fall and parasitize soil-dwelling scarab beetle larvae. We hypothesized that wind dissemination of M. ruficauda larvae is important in the host-finding process and that females lay eggs at heights that maximize parasitism of its concealed host. Through numerical and analytical models resembling those used to describe seed and pollen wind dispersal, we estimated an optimal oviposition height in the 1.25- to 1.50-m range above the ground. Our models take into account host distribution, plant availability and the range over which parasitic larvae search for hosts. Supporting our findings, we found that the results of the models match heights at which egg clusters of M. ruficauda are found in the field. Generally, work on facilitation of host finding using plants focuses on plants as indicators of host presence. We present a case where plants are used in a different way, as a means of offspring dispersal. For parasitoids that carry out host searching at immature stages rather than as adults, plants are part of a dissemination mechanism of larvae that, as with minute seeds, uses wind and a set of simple rules of physics to increase offspring success.     

超声波明渠流量计实地运行准确性验证方法的探讨

通过对现场安装后的量水堰槽几何尺寸测定和安装技术规范性的核准，研究超声波明渠流量计实地安装后计量准确性的验证方法。     

基于Landsat的黄河三角洲湿地景观时空格局演变

为全面揭示黄河三角洲湿地景观的演变,利用1973~2016年9期Landsat卫星影像,构建黄河三角洲湿地景观空间数据库,分析区域湿地景观的组成及其变化,应用景观格局指数分析方法,研究湿地景观格局演变的趋势,并结合质心模型探讨湿地景观空间位置的变化.结果表明：（1）黄河三角洲咸水湿地多分布于海岸带附近,淡水湿地多分布于河流沿岸,人工湿地多分布于距离海岸线15km以内的沿海区域以及河流沿岸.（2）黄河三角洲湿地总面积呈下降趋势,是由芦苇沼泽、翅碱蓬柽柳沼泽以及芦苇柽柳沼泽为主的自然湿地向人工湿地和非湿地的转换变化导致.（3）黄河三角洲湿地景观整体呈破碎化的萎缩趋势,景观空间构型不断朝破碎化、多样化,形状简单化的人工化特征突出的方向发展.（4）1973~1985年间,受黄河由刁口河流路改道清水沟流路初期的影响,加上充沛的淡水水源,黄河三角洲湿地呈以淡水湿地的东北向扩张变化主导;1985年后,黄河处于改道清水沟流路中后期,后又改至清8汊流路,加上黄河径流量的减少,使得区域湿地景观整体呈咸水湿地主导的东南方向萎缩变化.     

Environmental factors influencing the distribution of total and fecal coliform bacteria in six water storage reservoirs in the Pearl River Delta Region, China

The Pearl River Delta (PRD) is one of the most developed and densely populated regions in China. Quantifying the amount of pathogens in the source of drinking water is important for improving water quality. We collected water samples from six major water storage reservoirs in the PRD region in both wet and dry seasons in 2006. Results showed that external environmental factors, such as precipitation, location, as well as the internal environmental factors, i.e., physicochemical properties of the water, were closely related with the distribution of coliforms. Seasonally, the coliform bacterial concentrations in wet season were one to two orders of magnitude greater than those in dry season. Spatially, coliform bacterial levels in reservoirs near urban and industrial areas were significantly higher (p < 0.05) than those in remote areas. Correlation analyses showed that the levels of coliforms had close relationships with pH, temperature, suspended solid, organic and inorganic nutrients in water. Principal components analysis further demonstrated that total coliforms in the reservoirs were closely related with water physicochemical properties, while fecal coliforms were more associated with external input brought in by seasonal runo .     

区域空气质量监测网络优化布点方法研究

通过分析区域空气质量监测网络(RAQMN)优化布点的各种限制因素,利用空气质量模型模拟数据构建综合评价浓度,建立以最大贴近度为优化目标,以建设成本、地形、行政区域、人口布局和空间覆盖率等为约束条件的RAQMN优化布点方法.以珠江三角洲为案例背景,利用此方法分析了考虑常规污染物(SO2、NO2和PM10)、区域特征污染物(O3和PM2.5)和同时考虑包括常规、区域特征污染物等多种污染物组合3种情景下的RAQMN的优化布点.结果表明,该方法能够成功地应用于RAQMN的优化选址.与仅考虑常规污染物和仅考虑区域特征污染物的优化结果相比,同时考虑多种污染物优化结果的空间代表性更好,更能满足RAQMN的监测目标与优化布点的要求.     

Optimization of regional hazardous waste management systems: an improved formulation

The planning and design of regional hazardous waste management system (RHWMS) involves selection of treatment and disposal facilities, allocation of hazardous wastes and waste residues from generator to the treatment and disposal sites and selection of the transportation routes. An improved formulation based upon multi-objective integer programming approach is presented to arrive at the optimal configuration of RHWMS components. This formulation addresses important practical issues like unique characteristics of the hazardous wastes reflecting on waste–waste and waste–technology compatibility. A utility function approach is presented to integrate both cost and risk related objectives. An illustrative case example is presented to demonstrate the usefulness of the improved formulation as a tool which can be used by environmental planning agencies in regional planning for hazardous waste management.     

基于REST+RIA架构的水环境监测点位管理系统

针对目前水环境点位管理中系统化、规范化和标准化方面存在的问题,提出采用REST+RIA的软件架构,引入CA认证技术和GIS技术构建水环境点位管理系统,满足点位管理业务复杂性的要求.结合关键技术对系统的逻辑架构、部署方案、点位管理的业务流程进行了分析和介绍.