EcoTroph: Modelling marine ecosystem functioning and impact of fishing

EcoTroph (ET) is a model articulated around the idea that the functioning of aquatic ecosystems may be viewed as a biomass flow moving from lower to higher trophic levels, due to predation and ontogenetic processes. Thus, we show that the ecosystem biomass present at a given trophic level may be estimated from two simple equations, one describing biomass flow, the other their kinetics (which quantifies the velocity of biomass transfers towards top predators). The flow kinetic of prey partly depends on the abundance of their predators, and a top-down equation expressing this is included in the model. Based on these relationships, we simulated the impact on a virtual ecosystem of various exploitation patterns. Specifically, we show that the EcoTroph approach is able to mimic the effects of increased fishing effort on ecosystem biomass expected from theory. Particularly, the model exhibits complex patterns observed in field data, notably cascading effects and ‘fishing down the food web’. EcoTroph also provides diagnostic tools for examining the relationships between catch and fishing effort at the ecosystem scale and the effects of strong top-down controls and fast-flow kinetics on ecosystems resilience. Finally, a dynamic version of the model is derived from the steady-state version, thus allowing simulations of time series of ecosystem biomass and catches. Using this dynamic model, we explore the propagation of environmental variability in the food web, and illustrated how exploitation can induce a decrease of ecosystem stability. The potential for applying EcoTroph to specific ecosystems, based on field data, and similarities between EcoTroph and Ecopath with Ecosim (EwE) are finally discussed.     

燃煤电厂应对新标准的氮氧化物控制策略研究

介绍了我国燃煤电厂NOx排放标准及其控制技术发展状况,分析了NOx的排放现状及我国燃煤电厂NOx控制技术的特点及存在问题。结合新标准,提出在环境约束条件下效益―成本最大化的NOx控制策略。     

Coping with accelerating socio-technical systems

In 1997 a workshop was held on the subject of how to cope with accelerating technologies. These are industries such as aviation, air traffic control and biotechnology, amongst others, where the rate of technological development is significant. A number of papers were presented from a range of viewpoints and in a variety of different industrial contexts. The papers ranged from theoretical models to help understand the process of acceleration and its impact on organisational learning, to practical analyses of future potential risks in specific accelerating industries such as air traffic control. The aim of the papers and the workshop as a whole was to provide insight into the problems associated with accelerating technologies, and thereby derive measures to control or cope with such acceleration. The problems arising from acceleration, as predicted by the theoretical models and evidenced by experiences in accelerating industries (e.g. aviation) are manifold. Two examples of particular problems are unforeseen risks in an industry (a lack of forward vision), and a failure to learn adequately (i.e. in time) from incidents occurring in an organisation (a lack of constructive hindsight). There is also an incipient danger of society being driven by technology rather than being led by social needs. Even if each technology ultimately becomes ‘ultra-safe’, it will nevertheless have its own ‘event horizon’, limiting useful further progress. Each of the papers from the workshop is summarised and integrated into a three-part synopsis of the workshop. This covers the context of accelerating technologies, modelling their impacts, and deriving coping strategies. Four of the papers are included in their entirety as separate papers in their own right in this special issue of Safety Science.     

信息产业部电子第三十九研究所工业卫生状况分析与控制

着重阐述了信息产业部电子第三十九研究所的工业卫生状况 ,对超标作业点提出了控制及防范措施     

内燃机排放污染物控制技术研究

根据内燃机排放的废气中有害成分的形成机理 ,通过采取控制燃烧、控制燃料、废物再循环、安装设施及更改发动机设计等方法 ,使内燃机污染物排放得以控制     

长袋低压脉冲袋式除尘器在水泥立窑烟气除尘上的应用

比较了几种用于水泥立窑烟气除尘装置后 ,长袋低压脉冲袋式除尘器的优势凸现 ,对其在广州新华水泥厂实际使用出现的问题作了详细分析 ,并提出了解决办法     

调节风阀与风量的测量

根据玻璃熔窑助燃风系统 ,分析了工业炉燃烧自动控制过程中 ,调节风阀结构和流量计及其相对安装位置对风量测量及自控的影响 ,对通风自控系统设计、选型及安装具有一定的参考价值     

双极不对称预荷电静电增强过滤除尘技术的应用

双极不对称预荷电静电增强过滤除尘技术 ,是国家“九五”科技攻关课题所取得的成果之一 ,该技术采用双极不对称荷电增强方式 ,将普通静电增强效果与粉尘凝并机能有机地结合在一起 ,既提高了过滤除尘器的收尘效率 ,尤其是呼吸性粉尘的效率 ,同时又极大地改善了滤料粉尘层的结构 ,可显著地降低过滤阻力增值 ,节约运行能耗。笔者研究的该技术应用于焊接车间的焊接烟尘的治理上 ,取得了良好的效果。现场测试表明 ,该技术对焊接烟尘的滤除效率提高了 3% ,尤其对微细粉尘效果显著 ,2 μm粉尘穿透率相对下降了 4 7%。采用超细滑石粉高粉尘负荷测试结果表明 ,过滤阻力增值降低达 30 % ,清灰效果明显改善     

FUZZY ITERATION METHODOLOGY FOR RESERVOIR FLOOD CONTROL OPERATION1

ABSTRACT: Reservoir flood control is operated in real time so finding the optimal solution is unnecessary since it may not be practical. The key to reservoir flood control operation is quickly generating some feasible and effective alternatives and then selecting one among them. A fuzzy iteration methodology, which gives the objective weight and the relative membership degree of alternatives at the same time, is presented. Since the weight and relative membership degree are directly acquired from the recommended alternatives provided by decision makers, the results are more reasonable and realistic. Besides, the difficulty in giving weights is also avoided. With the aid of a robust and flexible decision support system, the effectiveness of decision making can be improved.     

城市污水处理计算机控制系统的应用研究

本文通过对污水处理行业所采取的计算机控制系统进行比较分析 ,得出结论 :采用基于现场总线的PC +PLC分级分布式控制形式 ,能够使系统具有很高的性能 /价格比。同时 ,将此结构进行拓展 ,成功应用于我国第一座自主开发的城市污水处理厂———沈阳南部污水处理示范厂。在系统中采用就地操作BIU +MFP(基本接口单元 +微现场处理单元 )与主PLC相结合的控制结构 ,通过GeniusBus(现场总线 )技术实现通讯处理 ,达到节约投资、提高系统安全性的目的