降雨径流对城市环境的污染分析

城市化的迅速发展,使城市不透水面积增大,降雨径流特别是初期雨水径流所带来的非点源污染日益严重,对城市水系构成严重威胁.分析城市降水径流包括路面、屋面及庭院径流的污染来源,降雨径流水质特性及污染物浓度历时变化规律,重点探讨降雨径流的初始冲刷效应、污染特征问题.     

基于SWMM的武汉市城区雨水管网初雨特性分析

以武汉市黄孝河城区雨水管网系统为例,基于SWMM模型对初期雨水特性进行模拟分析,以COD≥50mg/L为初期雨水的界定标准,分别从初雨持续时间、污染物冲刷比例及径流深度三方面综合分析降雨强度和汇水面积大小对初雨特性的影响。结果表明,初雨持续时间整体变化范围较大;初雨污染物冲刷比例和径流深度主要受降雨强度的影响,且变幅较大;武汉市城区最佳控制初雨径流深度可取7.00mm,初雨径流中污染物占整场降雨冲刷污染物总量比例的均值为56.8%。     

基于SWMM模型的青岛市典型工业园区径流污染特征分析

以沿海城市青岛市为研究对象,选取3场典型降雨对其典型工业园区道路径流污染物进行取样检测。分析区域径流污染物瞬时浓度,计算径流污染物的次降雨径流平均浓度(E_(MC))值,制作最小雨强的M(V)曲线图,拟合区域污染物冲刷量随径流量变化数据和污染物累积量,构建SWMM分析模型,确定冲刷模型参数。结果表明,初期雨强越大,径流污染物浓度越高;3场降雨中TN、TP、Cu、Zn的E_(MC)值均符合地表水环境质量Ⅴ类,COD、Pb的E_(MC)值存在超标情况;最小雨强依然(但不明显)存在初始冲刷现象;区域SS、COD、TN、TP、Cu、Zn、Pb的模拟结果与实测结果的标准偏差符合模拟要求,拟合的水质参数适应于SWMM模型径流模拟,为沿海城市径流污染的防治和径流模型的运用提供了技术支持。     

济南市雨水径流冲刷规律的研究

通过对不同下垫面径流雨水水质的检测,分析了各种雨水水质变化规律,建立适应济南市雨水径流冲刷规律的统计模型,为径流污染的定量分析和有效控制提供了依据.     

西安市城区降雨路面径流水质分析与评价

通过对2015年6~8月间4次降雨中西安市城区天然降雨和降雨道路径流的分区采样,分别于未央路、东大街、劳动路、南三环取降雨路面径流,在雁塔路中段路面取径流过程样,并参照相关标准对其混合样进行水质分析研究。结果表明,天然雨水水质状况较好,水质级别为Ⅰ类;各采样点路面径流水质评价结果均为劣V,其中主要污染物为COD(化学需氧量)、SS(悬浮物)、锰;径流中各污染物浓度随降雨过程均有降低,且在10min后各污染物浓度明显降低;对雨洪径流的收集工作应在径流形成15min后开始进行。     

快速城市化地区典型城市路面径流污染试验及特征分析

鉴于城市路面地表径流产生的非点源污染已成为快速城市化地区水体恶化的重要因素,研究城市路面径流污染特征对于城市水环境保护具有重要意义。在2013年6~7月对广州市黄埔大道和南沙区S358道路进行降雨径流连续采样,并开展水质检测,分析污染特征。结果表明,广州市黄埔大道降雨径流中化学需氧量、五日生化需氧量、氨氮、总磷、总氮、悬浮物以及重金属汞、铅的场次降雨污染物平均浓度(EMC)值分别为51.7、4.69、0.580、0.145、1.22、158、0.000 16、0.015mg/L;南沙区S358道路对应的EMC值分别为77.9、5.78、0.352、0.258、2.03、125、0.000 40、0.026mg/L。可见黄埔大道初期径流中化学需氧量浓度超过国家现行Ⅴ类标准值,S358道路初期径流中化学需氧量及总氮的浓度均超过国家现行Ⅴ类标准值;降雨路面径流-水质指标浓度变化存在初始冲刷效应,且与降雨特性、路面区域周围环境以及路面车流量密切相关。因此,在城市径流污染控制中需对路面径流冲刷、累积过程的影响因素进行综合考虑。     

城区路面雨水径流水文水质特征试验研究

鉴于研究城区路面径流水文过程与污染物变化特征可为有效利用城市雨水、控制非点源污染等提供参考依据,采用污染物分析方法对新乡市2010年城区路面3场降雨—径流的水文、水质过程进行采样分析。试验结果表明,路面径流系数在0.78～0.82之间,径流曲线形态与降雨过程线类似,两者波动幅度相对较小;径流初期污染严重,后期COD、SS浓度分别小于203、458mg/L;各指标的标准差率呈SS>COD>DO>pH值的趋势,这与各自浓度变化过程的指向性一致;径流中COD与SS之间的相关性较好,而DO与其之间的相关性较差。     

某大学校园及周边不同下垫面降雨径流污染过程研究

以大学校园及其周边区域降雨、径流和径流水质3年观测试验数据为依据,分析不同下垫面降雨过程、径流过程及污染物运移过程的规律及特征,计算出不同下垫面污染物输出系数。结果表明,雨水中氨氮浓度高于Ⅳ类水质标准,悬浮物、硝酸盐氮和COD浓度均低于最高水质标准;产流时间与产流前平均降雨强度呈幂函数关系,不同下垫面径流过程与降雨过程呈正相关关系;径流强度是径流携带污染物运移的重要影响因素,径流强度增加,径流携带污染物质量随之上升。污染物输出系数计算结果表明,屋面主要污染物为含氮污染物,餐饮街道主要为有机污染,不同下垫面悬浮物、硝酸盐氮、氨氮和COD输出系数均值分别为2294.91、7.21、14.86、430.34kg/hm2/a。     

对降雨径流水质污染特征的研究探讨

由于城市雨水径流对受纳水体的污染已日益显现,而且雨水资源的大量利用,雨水中的主要污染物的来源和形成成为主要的研究对象[1].主要针对阜新市的降雨径流水质污染状况进行监测.通过对雨水样品进行测试的结果表明,主要污染指标为COD、总磷、氨氮和SS.但污染物含量较低,雨水可以作为水源再回收利用.本研究可为阜新市雨水利用以及水环境综合整治长远规划提供重要依据.     

基于SWMM模型的服务区降雨径流和非点源污染控制研究

为解决高速公路服务区降雨径流污染物控制问题，以铁山服务区为例，采用SWMM模型构建了服务区水文和水质模型，基于LID设施选取原则与服务区场地条件，研究了不同暴雨重现期条件下无LID设施、渗透铺装与绿色屋顶组合、下凹式绿地与绿色屋顶组合、渗透铺装与下凹式绿地组合4种方案下服务区雨水径流及污染物的控制效能。结果表明，3种组合LID设施对服务区降雨径流量、径流峰值、污染物浓度和污染物总负荷均有一定的削减作用，其中渗透铺装与下凹式绿地的LID组合设施方案截污减排效果最优；LID设施在降雨强度小时对降雨径流和污染物的控制效能较降雨强度大时更强。     

小型锅炉烟尘测试时锅炉出力的计算

锅炉烟尘测试时,必须对锅炉出力进行测试。但监测中,许多小型锅炉往往不具备相关的计量装置和仪表,为解决这一问题,文章提出了用烟气量和空气过剩系数来计算锅炉的出力的公式,在实际使用中,该方法简单易行,其结果和实测值具有很好的一致怀。     

Unerroric of control of mutual compliance of the efficiency of hydrogen engines of unmanned vehicles in the conditions of mass production

The issues related to the reliability of hydrogen engines of unmanned vehicles and increasing the efficiency of using hydrogen as fuel when using the method of its production during the decomposition of hydrogen-containing molecules of liquid-phase organic compounds in a plasma discharge under the action of intense ultrasonic exposure are considered. Experiments have shown that as a result of decomposition in the acoustoplasma discharge of liquid hydrocarbons, solid-phase carbon-containing products are formed, chemical transformations occur in the liquid phase and hydrogen-containing combustible gas is formed. Hydrogen-containing gas can be used as fuel immediately after synthesis, i.e. it does not require separation, since in addition to hydrogen it contains only impurities of CO₂ and water vapor. The purpose of the study is to formalize the basic conditions for tightening the control of mutual compliance with the efficiency of hydrogen engines of the same series in the conditions of their mass production. Methods of mathematical statistics and hardware-software modeling were used in the study. The term “unerroric of quality mutual compliance control” is introduced to describe a set of hardware and software tools for such control. The principle of in-depth testing of the technical condition of such engines of one series is described in a multidimensional formulation of the quality control problem for three of their operating parameters at once. The conditions for increasing the mutual correspondence of the measured values of such parameters in the conditions of serial production of hydrogen engines are formalized.     

中国煤炭地下气化技术的发展

本文综述了煤炭地下汽化技术的国内外发展现状,对我国“长通道、大断面”煤炭地下气化新工艺给予了技术经济评述,并提出了发展煤炭地下汽化技术的政策建议。     

Review of theory of distortion and disintegration of liquid streams

Linear and nonlinear analyses of the instabilities and distortion of liquid streams injected into a gaseous media are discussed. The various fundamental mechanisms and the predictive capabilities for the distortions are emphasized. Round jets, planar sheets, annular sheets, and conical sheets are discussed in detail. The balance between capillary and inertial forces is primarily examined. The method for simplifying the analyses in the case of thin liquid sheets is discussed. The capabilities for representing the droplet size distribution that follows the stream disintegration are outlined.     

MgO膨胀剂细度对MgO水化和水泥浆体膨胀的影响

基于《水工混凝土掺用氧化镁技术规范》中的Ⅰ型氧化镁（MgO）,研究了该型MgO膨胀剂（MEA）细度对掺粉煤灰水泥浆体膨胀性能的影响。即采用X射线衍射分析(XRD)及同步热分析（TG DSC）分析了掺MEA水泥浆体中MgO的水化性。结果表明,养护温度相同时,MEA的细度对水泥浆体内MEA中MgO的水化和水泥浆体的膨胀无显著影响,产生的膨胀均能补偿水泥浆体的收缩;MEA的细度可从试验设计采用的45 μm筛筛余15%左右增加到30%左右,这将有利于MEA生产企业的节能降耗。     

机车车轮多轴疲劳强度安全评定的研究

使用ANSYS8.0软件对高速列车车轮进行了三维有限元分析,计算出车轮在直线、曲线和道岔条件下牵引、制动共6种工况时孔边薄弱部位的应力,分别通过Mises等效平均应力方法、Sines平均主应力方法和应力分量中考虑平均应力方法计算出应力在极值位置时的等效应力幅、等效平均应力,从而进一步算出车轮的安全系数,对其疲劳强度进行评定,并对3种方法进行了比较研究。     

Constructal optimization of the geometry of an array of micro-channels

This paper documents the geometric optimization of an array of circular and non-circular ducts. The optimization was carried out numerically using finite volume method. As optimal dimensions were independent of the array configuration, the numerical simulation was performed on a unit cell. Numerical optimization for circular, square and isosceles right triangle cross-sections of channels was performed. Based on the results of this investigation, some correlations were proposed to predict the optimal hydraulic diameter and dimensionless heat transfer per unit volume. In addition to examining the effect of pressure drop on these parameters, it was showed that among the different geometries of this study, square cross-section has the most efficiency for a given volume. The numerical results of the present study were compared with approximate results reported in the literature which a good agreement was observed.     

固体热辐射Yong性能分析

本文对漫灰均温物体在常物性条件下对外辐射传热的Ｙｏｎｇ值计算建立了数学模型。通过与物体内能Ｙｏｎｇ公式的数值计算比较,得出了辐射能量的Ｙｏｎｇ值不大于内能Ｙｏｎｇ值的结论。从初步的热射Ｙｏｎｇ值计算公式发现。Ｙｏｎｇ与物体表面辐射率有关。     

Measurements of concentration distribution of hydrogen jet using deflection of center of the laser spot

The main purpose of this work is to propose a new method to evaluate the concentration distribution of the hydrogen jet by using a He–Ne laser through the jet. This research attempts to apply the expression of concentration Gaussian distribution, the refraction formula of inhomogeneous refractive index medium, and the concentration inversion function to disclose the displacement of the center of the laser spot at different heights in the gas jet. The spot images of the laser beam passing through the gas jet at three vertical heights z = 10d, 20d, 30d, and different radial positions are obtained. The radial spatial asymmetry of the gas jet is also found in the experiment. Finally, the calculated concentration distribution curve and the fluent simulation curve, it is found that the two results are very similar. Our findings show that the error between the concentration distribution of this method and the simulated concentration distribution reaches 2.43%.     

Heat of vaporization of mixtures

General expressions for the heat of vaporization of mixtures at constant pressure; at constant temperature; and at constant pressure, temperature, and composition are proposed. The last one is related to the liquid-vapor interface where steady vaporization or condensation is taking place. Numerical examples by the proposed expressions are shown for binary mixtures of HCFC22(R22) and (HCFC123(R123) © 1997 Scripta Technica, Inc. Heat Trans Jpn Res, 25(1): 12–24, 1996