利用遗传算法进行排水管网优化设计

提出对于不同管径以不同最大流速进行限制,在遗传算法优化过程中,各个管段所对应的可行管径数目不同,使得遗传算法的搜索更具有目的性,搜索速度更快,并且还可保证管网系统的全局优化。     

优选管径法在给水管网计算中的应用

针对给水管网系统所面临的改扩建问题,建立了给水管网系统实用优化改扩建模型。采用优选管径法求解,一次性解决了求解管径标准化的难题。同传统的经济流速法相比,其计算时间短,计算操作简单,计算结果经济,可以大大减轻设计人员的工作量。     

给水管网扩建工程优化设计方法探讨

结合景德镇市给水管网现状,从管网平差中两节点间多管的简化方法及水源简化两方面,对给水管网扩建工程优化设计方法进行了研究和探讨,提出了新的计算方法并据此编制了管网平差程序。     

给水管网计算中的数据转换方法

在给水管网计算中,通过建立环-管段矩阵、环-节点矩阵以及输入节点流量、节点坐标等少量数据,通过计算和数据转换,便可求得经济管径、管段设计流量、节点水压值、水厂供水量、管网造价、年费用折算值等。采用该方法进行管网计算,可以减少40%～70%的计算时间。     

环状给水管网的初始流量分配

利用机器初分流量可显著加快给水管网的设计进度。在现有的多种初分流量方法中以文献［１］提出的较为简捷实用。本文在进一步阐述该法时,纠正了［１］中的某些不足,并且用两个例子具体说明怎样运用来初分流量。     

基于遗传算法的天然气管网优化

随着城市化建设发展步伐的加快,天然气管网建设规模与复杂程度呈明显上升趋势,这给天然气管网优化提出更高要求。基于此,本文围绕天然气集输管网的参数优化设计模型,针对目标函数多峰性、局部极小点存在等特点,以管道建设费用为目标函数,采用遗传算法建立天然气集输管网的参数优化设计模型,以期提高全局收敛性,加快系统求解速度。     

应用ObjectARX开发给水管网GIS系统

在对ＡｕｔｏＣＡＤ２０００、ＯｂｊｅｃｔＡＲＸ,给水管网计算机管理系统和ＧＩＳ分析的 ,提出给水管网计算机管理系统开发的一般过程和用ＯｂｊｅｃｔＡＲＸ和扩展字典功能进行管网系统ＧＩＳ开发的方法,并通过编写ＷＤＯＣ软件系统得到验证。     

给水管网硝化作用控制方法研究进展

介绍了氯胺消毒管网中的硝化作用及其控制方法,并对控制方法进行了总结和展望。在采用氯胺消毒的给水管网中,存在着硝化反应发生的可能性。硝化作用会造成出水亚硝酸盐含量升高、消毒剂含量降低、异养菌繁殖等危害。国内外对氯胺消毒管网中硝化作用控制方法的研究主要集中在改变出厂水水质条件-pH、提高消毒剂的浓度、优化氯胺投加方式、管道冲洗、硝化潜能曲线及投加亚氯酸根控制硝化作用。目前以上的控制方法对硝化作用起到了一定的抑制作用,但是存在控制效果不确定、不具有长期性或者增加生成消毒副产物的风险。因此,对硝化作用的控制方法有待深入研究。笔者提出了氯胺、二氧化氯联合消毒控制硝化作用的方法。     

给水排水管网系统课程教学改革与实践

给水排水管网系统是给水排水工程专业的一门主干专业课程。我们根据平时教学的实践,对本课程教学内容、方法、手段、考核方式等方面的教学改革作了一定的阐述,以期获得最好的教学质量。     

珠海市供水管网模型的建模与应用

为准确分析水厂新建对多水厂联合供水系统的影响,采用MIKE URBAN WD对珠海市陆域净化水系统进行水力建模,创新水量分配方法,采用抄表数据经定位处理后进行节点流量挂靠,使模型具有较高的精度;建模后应用于梅溪水厂新建并网的影响评估,得出梅溪水厂的选址、规模及出厂压力基本合理,不会对现有给水系统水量、水压等造成水力异常...     

Prediction of Bromate Removal in Drinking Water Using Artificial Neural Networks

In treatment of natural water resources, bromide transforms into carcinogenic bromate, especially during the ozonation process. Adsorption was used in the experimental part of this study to remove this harmful compound from drinking water. For this purpose, technically, HCl-, NaOH-, and NH₃-modified activated carbons were used. Scanning Electron Microscopy (SEM) and Brunauer–Emmett–Teller (BET) analyses were carried out within the characterization study. Moreover, the effects of diameters and heights of adsorption columns, flowrate, and particle size of adsorbent were investigated on the removal amounts of bromate. Optimum conditions were obtained from the experiments, and regional/real samples were collected and analyzed. After the experiments, an artificial neural network (ANN) was used to predict bromate removal percentage by using the observed data. Within this context, a feed-forward back-propagation ANN was chosen in this study. Additionally, the transfer function was selected as tangent sigmoid and 3 neurons were used in the hidden layer. Particle size and amount of the activated carbon, height and diameter of the column, volumetric flowrate, and initial concentration were selected as the input variables. Bromate removal percentage was selected as the output. It was found that the model an R value of 0.988, RMSE value of 3.47 and mean absolute percentage error (MAPE) of 5.19% in the test phase.     

供水管网水样R2 A培养基细菌总数测定及其影响因素探究

满足饮用水卫生标准的城市给水处理厂净水在输送过程中受到污染,致使管网水中细菌的重新生长和繁殖,从而导致饮用水水质存在安全隐患。以南方某城市管网为研究对象,运用ExpAssoc模型对管网水中细菌菌落总数与细菌出现概率进行模拟,并探讨了管网水的温度、浊度、余氯三个常规指标与水样细菌总数之间的关系。结果表明ExpAssoc模型可以较好地模拟管网水中细菌菌落总数和细菌出现概率的关系,相关系数R2均大于0.97。水温与管网水细菌菌落总数呈正相关关系;管网水高浊度与细菌出现频率亦存在正相关性。余氯对管网水细菌存在水平确实存在影响,当余氯量小于1.0 mg／L时,细菌出现率为100％;当余氯量大于1.0 mg／L时,细菌的出现与余氯值并不相关,呈随机分布状态。     

邻苯二甲酸酯在水环境中的分布及去除技术研究进展

邻苯二甲酸酯(PAEs)是我国地表水和污水处理厂中高频检出的一类微量难降解有机污染物,在水环境中的浓度一般是μg/L级别,但对人体具有内分泌干扰毒性和生殖毒性,是关系到二级生化出水深度处理和再生水安全利用的重要污染物.文中系统综述了PAEs的理化性质、环境风险和在水环境中的分布特征,总结了国内外污水处理厂中PAEs的处...     

遗传算法在过程综合混合整数非线性规划中的应用

针对过程综合混合整数非线性规划问题提出了一种混合遗传算法，该算法对整数变量进行编码，而对连续变量则采用连续化遗传算子进行处理，使得算法与原问题的对应更加自然，也更有效。另外，还针对常见的提前收敛或局部最小现象提出几种算子，实例表明本算法具有较强的全局优化能力。相对于传统遗传算法具有速度快、精度高、可操作性强等特点。     

给水管网细菌再生长可能机制及影响因素分析

给水管网中细菌再生长是管道的表面性质和流体流速特点及细菌对贫养环境的适应造成的。其主要影响因素包括：余氯量、可同化尊机喳（AOC）、管材及管道特征等。余氯量是控制细菌再生长的关键因素：AOC是管网水中细菌生长潜力的首要指标;当水中的磷为l～3μg/L甚至低于1μg/L时,磷就成为管网水中细菌再生长的主要限制因素。     

给水管网中含铝水垢对微量金属元素蓄积释放特性综述

该文探讨了含铝沉积物对微量金属元素的蓄积作用,以及原水水质、水处理药剂、溶液pH和水流状态等因素改变时对含铝沉积物结构稳定性和微量金属元素释放特性的影响。为减少输配水过程中微量金属元素的释放,保障管网稳定运行和居民饮水健康,建议通过水质调节控制管网中含铝沉积物的生成量。该研究给出了常见微量金属元素的最大允许蓄积量,并指出了今后的研究方向。     

A Mixed Coding Scheme of a Particle Swarm Optimization and a Hybrid Genetic Algorithm with Sequential Quadratic Programming for Mixed Integer Nonlinear Programming in Common Chemical Engineering Practice

In this paper, mixed integer nonlinear programming (MINLP) is optimized by PSO_GA–SQP, the mixed coding of a particle swarm optimization (PSO), and a hybrid genetic algorithm and sequential quadratic programming (GA–SQP). The population is separated into two groups: discrete and continuous variables. The discrete variables are optimized by the adapted PSO, while the continuous variables are optimized by the GA–SQP using the discrete variable information from the adapted PSO. Therefore, the population can be set to a smaller size than usual to obtain a global solution. The proposed PSO_GA–SQP algorithm is verified using various MINLP problems including the designing of retrofit heat exchanger networks. The fitness values of the tested problems are able to reach the global optimum.     

The Degradation of Polyglycolide in Water and Deuterium Oxide. Part II: Nuclear Reaction Analysis and Magnetic Resonance Imaging of Water Distribution

Magnetic resonance imaging (MRI) and scanning microbeam nuclear reaction analysis (NRA) were used to monitor changes of water ingress into polyglycolide (PGA) disks with degradation time. MRI detects H₂O, whereas NRA is sensitive to D₂O. The acid-catalysed hydrolysis of the ester is significantly slower in D₂O than H₂O because of the kinetic isotope effect. This behaviour was investigated in Part I. In this paper, NRA was used to investigate PGA hydration in buffers made from D₂O, and NRA and MRI experiments were performed on samples degraded buffers made from a 50% mixture of D₂O and H₂O (D₂O/H₂O 50:50) to allow a comparison between the two techniques. The NRA and MRI results provide direct evidence in support of the four-stage reaction-erosion model reported in previous literature, and show that this model applies to polymer degradation in heavy water and in a buffer made from D₂O/H₂O 50:50. It is believed that this is the first time that NRA and MRI have been compared for the same hydrating system.     

The Effects of Ozonation,Biological Filtration and Distribution on the Concentration of Easily Assimilable Organic Carbon (AOC) in Drinking Water

The concentration of easily assimilable organic carbon (AOC) as determined with growth measurements using wo bacterial cultures, increased linearly with ozone dosage at values below 1 mg O₃/mg of C. Moreover, a linear relationship was found between AOC increase and the decrease of UV absorbance of water after ozonation with various dosages. Biological filtration in water treatment reduced AOC concentrations, but the remaining values were above the AOC concentration before ozonation. This AOC removal was attended with an increased colony count in the filtrate. The AOC concentration of drinking water produced by the application of ozone in water treatment decreased during distribution. The greatest decrease was observed with the highest AOC concentration. Also in this situation, the highest colony counts were found. To date, ozonation is applied in seven water treatment plants in the Netherlands.