关于对环卫机械液压系统污染物控制的研究

相比于控制技术,液压传动系统具有更好的优越性,且已在各领域当中得到了广泛的应用。但是在实际的工作运行当中,液压系统的污染故障率相当高,在75％左右。因此,对液压系统污染物的控制十分必要,是液压设备可靠正常运行的保障。下面,本文就环卫机械对液压系统污染物的控制进行研究,以为实际的污染物控制提供参考。     

系统动力学模型在城市发展规划环评中的应用——以山西省临汾市为例

鉴于作为评价对象的城市社会经济环境复合系统具有多目标、多要素、动态关联等突出的系统动力学特征,选择和应用系统动力学方法开展城市发展规划环评在理论上具有可行性和技术优势.作为典型资源型城市的山西省临汾市正面临转变发展方式和加快环境治理的紧迫要求,本文依托该市转型发展规划环评工作,在全面识别和剖析城市发展要素、现状问题及其成因基础上,以经济发展、产业结构、节能减排和环境改善为重点研究了规划要素间的动态反馈关系,以此构建城市转型发展规划环评SD模型,并对4个规划替代方案进行模拟和评价.结果显示,在环境目标刚性约束下所有替代方案均不能实现人均GDP翻番的较高经济增长目标,其中以较强环境约束为特征的"方案III"具有最好的环境与经济综合效果.据此评价建议临汾市应在确保实现环境改善目标的前提下主动放缓工业增长速度,同时加快以"煤焦铁电"为代表的主导产业结构调整并继续加大节能减排力度,全面提高城市可持续发展能力.     

书讯

<正>张殿印、王海涛主编的《袋式除尘器管理指南—安装、运行与维护》,由机械工业出版社于2013年11月出版,全国新华书店和机械工业出版社官网发行。该书是专门介绍袋式除尘器安装、运行与维护的管理技术书。全书约75万字,共分为8章,分别介绍袋式除尘器的分类、性能、选择,袋式除尘器安装准备、安装流程,安装方法与验收,袋式除尘器调整试验、运行操作、维护保养、故障排除和袋式除尘系统运行管理。本书内容全面,资     

600 MW机组加装增压风机旁路系统的探索

应环保政策要求,火电厂烟气旁路系统必须在2014年底前取消,如何解决取消烟气旁路后锅炉的安全运行问题呢?漳山电厂提出加装增压风机旁路系统的方案,并通过检测风烟系统阻力,进行可行性研究。该方案实施后,完全达到预期效果,当增压风机故障时,烟气经旁路烟道进入吸收塔,保障了锅炉正常运行,实现了增压风机在线检修。     

简讯

<正>太湖蓝藻不成灾先进科技作用大近日,中国环保网记者在太湖周边采访得知,由于采取了"智能实时监测"等科技治藻手段,今年太湖没有发生一起蓝藻污染水质事件。蓝藻不成灾,苏州、无锡、雷州三个环太湖区的市民喝上了干净、放心的水。让太湖有了清澈的湖水、丰茂的水草、悠然自得的鱼虾……     

Biostability in distribution systems in one city in southern China：Characteristics, modeling and control strategy

This study investigated the bacterial regrowth in drinking water distribution systems receiving finished water from an advanced drinking water treatment plant in one city in southem China. Thirteen nodes in two water supply zones with different aged pipelines were selected to monitor water temperature, dissolved oxygen （DO）, chloramine residual, assimilable organic carbon （AOC）, and heterotrophic plate counts （HPC）. Regression and principal component analyses indicated that HPC had a strong correlation with chloramine residual. Based on Chick-Watson＇s Law and the Monod equation, biostability curves under different conditions were developed to achieve the goal of HPC 100 CFU/mL. The biostability curves could interpret the scenario under various AOC concentrations and predict the required chloramine residual concentration under the condition of high AOC level. The simulation was also carded out to predict the scenario with a stricter HPC goal （≤50 CFU/mL） and determine the required chloramine residual. The biological regrowth control strategy was assessed using biostability curve analysis. The results indicated that maintaining high chloramine residual concentration was the most practical way to achieve the goal of HPC ≤ 100 CFU/mL. Biostability curves could be a very useful tool for biostability control in distribution systems. This work could provide some new insights towards biostability control in real distribution systems.     

Primary neuronal-astrocytic co-culture platform for neurotoxicity assessment of di-(2-ethylhexyl) phthalate

Plastics such as polyvinyl chlorides （PVC） are widely used in many indoor constructed environments; however, their unbound chemicals, such as di-（2-ethylhexyl） phthalates （DEHP）, can leach into the surrounding environment. This study focused on DEHP＇s effect on the central nervous system by determining the precise DEHP content in mice brain tissue after exposure to the chemical, to evaluate the specific exposure range. Primary neuronal-astrocyte co-culture systems were used as in vitro models for chemical hazard identification of DEHP. Oxidative stress was hypothesized as a probable mechanism involved, and therefore the total reactive oxygen species （ROS） concentration was determined as a biomarker of oxidative stress. In addition, NeuriteTracer, a neurite tracing plugin with ImageJ, was used to develop an assay for neurotoxicity to provide quantitative measurements of neurological parameters, such as neuronal number, neuron count and neurite length, all of which could indicate neurotoxic effects. The results showed that with 1 nmol/L DEHP exposure, there was a significant increase in ROS concentrations, indicating that the neuronal-astrocyte cultures were injured due to exposure to DEHP. In response, astrocyte proliferation （gliosis） was initiated, serving as a mechanism to maintain a homeostatic environment for neurons and protect neurons from toxic chemicals. There is a need to assess the cumulative effects of DEHP in animals to evaluate the possible uotake and effects on the human neuronal system from exoosure to DEHP in the indoor environment.     

Experimental study on filtration and continuous regeneration of a particulate filter system for heavy-duty diesel engines

This study investigated the filtration and continuous regeneration of a particulate filter system on an engine test bench, consisting of a diesel oxidation catalyst（DOC） and a catalyzed diesel particulate filter（CDPF）. Both the DOC and the CDPF led to a high conversion of NO to NO2 for continuous regeneration. The filtration efficiency on solid particle number（SPN） was close to100%. The post-CDPF particles were mainly in accumulation mode. The downstream SPN was sensitively influenced by the variation of the soot loading. This phenomenon provides a method for determining the balance point temperature by measuring the trend of SPN concentration.     

Acute and chronic toxic effects of Pb2+ on polychaete Perinereis aibuhitensis：Morphological changes and responses of the antioxidant system

Perinereis aibuhitensis was used to assess adverse biological effects caused by acute and chronic Pb2＋exposure in artificial seawater under controlled laboratory conditions. In 96-hr acute toxicity experiments,the morphological changes showed a positive time/dose-dependent tendency,and the 96-hr LC50 value of Pb2＋was 686.41 mg/L. The responses of enzymatic and non-enzymatic antioxidants in tissues including catalase（CAT）,peroxidase（POD）,superoxide dismutase（SOD）,glutathione peroxidase（GSH-PX）,malondialdehyde（MDA） and the content of total soluble protein（TSP）,were investigated on days 1,4,7 and 10 after Pb2＋exposure under chronic toxicity testing. Results showed that the activation of the antioxidant system in P. aibuhitensis depended on the Pb2＋concentration and the duration of exposure time.Specifically,POD and SOD activities were induced on the first day of the exposure and decreased to the control level on day 10 after exposure. Therefore,these two indexes could be used to indicate oxidative stress associated with P. aibuhitensis exposure to Pb2＋.     

餐厨/厨余垃圾“不入土”,变废为宝“再消化”——北京绿色空间生物科技有限公司的循环之道

餐厨及厨余垃圾是有机垃圾的一种,餐厨垃圾是指餐饮服务单位在食品加工、饮食服务、单位供餐活动中产生的食物残渣、残液和废弃油脂等废弃物。厨余垃圾是指,家庭中产生的易腐食物垃圾,主要包括剩菜、剩饭、菜帮菜叶、瓜果皮核废弃食物等。餐厨及厨余垃圾含有大量的有机质,如果将它们能就地处理变成有机肥,既可省下用作填埋场的土地,还能节约运输它们的车辆和能源,防止滋生蚊蝇和细菌。不仅保护了环境,还滋养了土地。