基于均匀实验设计的曝气池柔性设计方法

为了解决污水处理过程由于水质水量等不确定性参数偏离设计值所引发的问题,提出了一种基于均匀实验设计的曝气池柔性设计方法。该方法用均匀设计产生不确定性参数区域内具有代表性的不确定性情形,用因子设计生成应对这些情形的操作方案,在柔性瓶颈处通过直观分析寻找改进设计方案的策略。从案例研究可以看出,传统的没有系统化地考虑不确定性参数变化的设计方法,所设计的曝气池在一些不确定性情形下,可能无法正常运行,而本方法有助于避免这一缺陷。     

Quantized control settings based tuning of a heaving wave energy converter in irregular seas

The increasing awareness of environmental issues attracts more attention on environmentally friendly energy sources. This leads to increasing research on effective use of renewable energy sources. Among them, wave energy offers a high potential. The wave energy converter systems used for transforming the wave energy into electrical energy have been a main research topic for decades. However, only a few of these systems has been successfully implemented. There seems to be some technical problems one of which is on their control applications. It has been reported that by means of appropriate control implementation, the performance of the wave energy converter system could be improved considerably. In literature, many different control techniques are reported. They appear to be weak due to implementation related restrictions. The present study proposes a novel control technique that is far more practical based on quantization of control settings. Various quantization levels and their effect on system power capture performance are studied. The technique assumes use of realistic off-the-shelf components with realistic features. The proposed method utilizes time-series-analysis technique with online parameter estimation feature. This new method does not require any knowledge of previous or future states of any of the system or sea state parameters, but only the currently available and measurable ones. The approach of the new control technique sets it apart from most of the previously reported ones. Therefore, the proposed technique is not only very much practical but also very much useful in improvement of the system power performance relative to passive techniques.     

Residents' willingness to pay for improved liquid waste treatment in urban Ethiopia: results of choice experiment in Addis Ababa

This paper discusses residents’ willingness to pay (WTP) for improved liquid waste treatment in Addis Ababa based on data collected in 2011 using random parameter logit model. Findings indicate that respondents are willing to contribute for improved liquid waste treatment with higher quantity and quality. Their mean WTP for the medium improvement scenario is found to be 15.53 ETB (0.93 USD) per month. The compensation surplus tends to increase from the status quo to the alternative scenarios with aggressive improvement. Finally, the paper concludes by indicating the socioeconomic difference across households, and sub-cities need to be considered in designing environmental protection plans for the city.     

镧负载沸石壳聚糖复合吸附剂高效除磷性能研究

本研究制备合成一种新型可高效除磷的镧负载复合吸附剂材料(La-MZ/CTS),考察了材料的表面特性以及投加量、初始溶液pH、共存阴离子等因素对除磷效果的影响.SEM、BET和EDS分析说明负载镧后,材料表面均匀覆盖了La(OH)3并且表现出较大的孔径和比表面积,分别为16.681 nm、32.342 m2·g-1材料对...     

铁系金属对氯代有机物的还原脱氯研究进展

介绍了金属还原法中铁系金属还原脱氯去除氯代有机物的机理及研究现状,概括总结了催化剂类型、两种金属的比率、氯代有机物种类、溶液pH、反应温度、污染物初始浓度等因素对脱氯效果的影响,针对目前存在的问题提出了未来发展的方向。     

大鹏澳网箱养殖海域海水溶解氧浓度影响因素分析

根据2001和2002年在大鹏澳网箱养殖海域的观测数据,探讨表层海水溶解氧(DO)浓度的变化特点及与其他环境因子的关系.结果表明研究海域的DO浓度在4.52～8.35 mg/L,总体、网箱区外、网箱区内的平均值分别为6.24、6.81、5.89 mg/L,DO季节平均浓度在冬季、春季、夏季、秋季分别为7.52、6.66、5.44、5.33 mg/L.t检验表明,在95%的置信水平上DO浓度在网箱区内比网箱区外明显降低,冬季明显高于其它季节,春季明显高于夏季和秋季.逐步线性回归分析结果显示,海水DO浓度按相关程度的高低依次与下列5个环境因子的强度显著负相关(r=-0.945,p=0.025)海水温度＞底质硫化物＞海水亚硝酸盐＞海水磷酸盐＞海水氨和铵盐.     

Two-step hydrothermal conversion of biomass waste to humic acid using hydrochar as intermediate

Converting biomass materials to humic acid is a sustainable method for humic acid production and achieve biomass valorization. A two-step hydrothermal treatment method was adopted in this study to produce humic acid from corn stalks. In the first step of the process, hydrochar was prepared at different hydrothermal temperatures and pH values. Their chemical properties were then analyzed, and the hydrochar-derived humic acids were produced under alkaline hydrothermal conditions (denoted as HHA_alk). The hydrochar, prepared under high temperature (200 °C) and strong acidic (pH 0) conditions, achieved high HHA_alk yields (i.e., 67.9 wt% and 68.8 wt% calculated based on weight of hydrochar). The sources of HHA_alk formation were as follows: 1) production in the hydrochar preparation stage, and 2) increment under the alkaline hydrothermal treatment of hydrochar. The degree of hydrochar unsaturation was suggested as an indicator for evaluating the hydrochar humification potential under alkaline hydrothermal conditions. This study provides an important reference for the preparation of suitable hydrochar with high hydrothermal humification potential.     

加油站安全监控预警系统研发与应用

加油站安全监控系统采用分散监控、集中管理与网络传输的监控策略,不仅可实现传统的视频监控和记录功能,还对加油站进出车辆情况、收费情况、设备运行情况以及加油站工作情况进行实时监视和记录;在可实现加油站现场安全参数(如温度、液位、可燃气体浓度等)的实时采集与处理,对在加油站内部及周边动态安全状况实时分析的基础上,根据警情设定自动作出相应的应急反应,如打开声光报警装置等;同时,对危险源可能发生的事故后果(包括死亡、重伤和轻伤等)进行模拟与分析,进而为事故的应急救援提供决策与支持。     

构造煤分层对煤单轴压缩力学特性影响的颗粒流模拟

为了研究构造煤分层对煤的力学特性影响程度,采用颗粒流数值模拟方法研究不同赋存参数的构造煤分层对煤的单轴压缩力学特性的影响规律,从受荷后的裂纹分布和试样破坏形式2个方面分析试样压缩过程中细观力学响应机制。研究结果表明:构造煤分层厚度和倾角是影响煤的单轴压缩力学特性的重要参数,其中倾角主要影响内部裂纹的类型和分布,构造煤厚度主要影响煤的单轴抗压强度;单轴压缩下煤的破坏类型主要包括沿交界面的层裂破坏、拉伸破坏和复合破坏3种类型,构造煤分层倾角较小时,更容易由于构造煤挤出效应导致的失去承载能力,随倾角增大,挤出效应减弱,单轴抗压强度有增大趋势。     

北方寒冷地区SBR设计参数的修正及其探讨

在城市污水处理系统中,通常的SBR工艺设计参数多适用于常温的环境即15～30℃。而我国北方寒冷地区,冬季水温一般在6～10℃,如果仍按照常规参数进行工程设计,在一定程度上不能满足北方城市污水处理系统的实际情况,出水水质很难达到排放要求。因此,应把温度参数与反应动力学联系起来,通过试验和工程实例对SBR的常规设计参数进行低温下的修正,以适应北方寒冷地区的城市污水处理厂的设计要求。