A new simple water flow system for accurate continuous flow tests

A new simple water flow system is described. The system can be used for rates of flow ranging from millilitres to litres, and has proved to be accurate and easy to handle.     

循环水养殖系统中水动力特性及其与鱼类相互影响研究进展

水产品含有丰富的蛋白质及人体所需的营养元素,随着人民生活水平的提高,水产养殖业迅速发展,为解决传统水产养殖业受环境污染、食品安全、自然灾害、疾病频发等方面的困扰,工厂化循环水养殖成为水产养殖业转型发展的养殖新模式之一。循环水养殖系统中的养殖池水体是养殖动物赖以生存与健康生长的场所,优化养殖池环境是实现鱼类等水产动物健康养成的关键。本文以建立环境友好、水质优良、资源节约、动物健康的高效绿色养殖模式为目标,以实现水产品的高品质、高产出为宗旨,综述了循环水养殖系统中水动力研究方法,以及养殖池内流场、固体颗粒物集排污、可溶性与悬浮污染物输移扩散、增氧性能、鱼类与流场相互影响等密切相关的水动力问题,并就当前循环水养殖系统水动力研究中存在的问题进行了总结,提出了加强养殖池水动力及其与结构设计、优化等关键技术的集成应用研究,以及基于养殖动物开展水动力学研究等未来发展建议,以期为循环水养殖事业的发展提供科学参考。     

基于组态王软件的双容水箱流量监控系统设计

文章采用组态王软件设计双容水箱流量监控系统,运用扩散硅液位变送器进行液位测量,电动调节阀为执行器,采用PI算法控制双容水箱流量。经过实验,可以实现在系统工作时的实时监控与速度曲线显示,当双容水箱受到阶跃扰动时,控制效果最优,上升时间为22 s,超调量为26.7%,达到较为良好的监控要求。     

2-Methylisoborneol and geosmin uptake by organic sludge derived from a recirculating aquaculture system

In a previous study on a recirculating fish culture system, levels of geosmin and 2-methylisoborneol were found to decrease when culture water was recirculated through the anaerobic sludge digestion treatment stage of the system. This finding led us to the present study in which the geosmin and 2-methylisoborneol removal capacity of the sludge derived from this treatment stage was examined in vitro. It was found that reduction of off-flavor compounds by the sludge was mediated by both chemical/physical sorption and biological degradation. At geosmin and 2-methylisoborneol concentrations within the range of those experienced in fish culture systems, chemical/physical sorption by the sludge was found to account for a 93% reduction in geosmin and a 79% reduction in 2-methylisoborneol from the overlying water within 48 h of incubation. Combined with the biological degradation taking place in the sludge, a complete removal of these compounds from the water phase occurred within 9 days of incubation. By means of repeated washing of the geosmin and 2-methylisoborneol contaminate sludge with clean water, relatively small amounts of these compounds were released from the sludge, a possible indication for the fact that absorption, rather than adsorption, underlies the chemical/physical removal process.     

电渗析技术处理LNG工厂循环冷却系统排污水研究

湖北LNG工厂循环冷却水系统每日排污量高达1 200m3,直接排放不仅造成水资源的浪费,同时对下游污水处理厂的运行产生较大冲击。为提高该部分废水的重复利用率,设计采用"多级连续式电渗析除盐系统"对其进行脱盐处理后回用于循环水系统。经计算,50m3/h的电渗析装置设计流速采用V=5.0cm/s,设计总脱盐率ε=75%⁸0%,产水电导率30080%,产水电导率300³50μs/cm。装置建成后调试结果表明,最佳操作电压为110V,最适宜进水流量为50m3/h,产水各项指标满足预期设计要求。每年可减少新鲜水消耗和废水排放各30×104 t,产生直接经济效益约60万元。     

A simple simulation method for river self-purification studies

A simple simulation system is described for the study of river self-purification processes. A linear relationship between the organic load and the critical deficit on the sag curve was obtained for each temperature, corresponding to 36–52 per cent assimilation. The rate is not constant, and the monomolecular theory is not suitable to describe the results. Two distinct phases are observed. Nitrification appears as a second and distinct sag in the oxygen curve. It is limited by oxygen transfer and equilibrates at an O₂ tension of 0·6–1·05 mg 1⁻¹.     

垃圾处理场与污水池的防水处理

针对污水处理池防水处理的特殊性,介绍了其防水设计方案、选用主要材料的性能特点和施工方案,并就施工中要注意的几个问题加以阐述.     

Mathematical model for analysis of recirculating vertical flow constructed wetlands

The recirculating vertical flow constructed wetland (RVFCW) was developed for the treatment of domestic wastewater (DWW). In this system, DWW is applied to a vertical flow bed through which it trickles into a reservoir located beneath the bed. It is then recirculated back to the root zone of the bed. In this study, a compartmental model was developed to simulate the RVFCW. The model, which addresses transport and removal kinetics of total suspended solids, 5-day biological oxygen demand and nitrogen, was fitted to kinetical results obtained from pilot field setups and a local sensitivity analysis was performed on the model parameters and operational conditions. This analysis showed that after 5 h of treatment water quality is affected more by stochastic events than by the model parameter values, emphasizing the stability of the RVFCW system to large variations in operational conditions. Effluent quality after 1 h of treatment, when the sensitivity analysis showed the parameter impacts to be largest, was compared to model predictions. The removal rate was found to be dependent on the recirculation rate. The predictions correlated well with experimental observations, leading to the conclusion that the proposed model is a satisfactory tool for studying RVFCWs.     

层流病房的净化空调设计

简要介绍了层流病房的概念,结合层流病房净化空调要求,论述了层流病房净化空调的两种设计方法,并以具体工程为例深入阐述了自循环净化机组的设计方法,指出两种设计方法各有利弊,应根据实际情况合理选用。     

储罐爆炸事故碎片抛射距离简易预测模型

摘 要：为合理确定液化石油气储罐爆炸事故中爆炸碎片的抛射范围,基于动力学原理和理论分析构建了爆炸碎片抛射距离预测模型,并借鉴某液化石油气爆炸事故案例有关数据进行数值模拟和验证分析。结果表明：模型预测值与事故数据及前人的Monte Carlo数值模拟结果较为吻合,模型对于球罐和柱形储罐爆炸事故都具有很好的适用性。该模型可快速便捷地预测爆炸碎片的危害范围,预测结果可为应急部门救援决策提供技术支持,同时也可为石油化工园区规划建设及风险管控提供理论依据。     

A pneumatic dosing apparatus for flow-through bioassays

A multichannel pneumatic injector, when used with an equal-volume diluter, possesses several advantages over the mechanical approach to toxicant dosing. The system is reliable and highly versatile, capable of maintaining an unlimited range of toxicant levels in flow-through bioassays. Use of a single toxicant concentration eliminates the necessity of preparing several stock solutions. Automatic reloading of the injector syringes reduces maintenance.     

A computer program for randomizing toxicity bioassays

A short program, written in Applesoft (tm) BASIC, is presented which randomly assigns concentrations of toxic substance to containers prior to performing a toxicity bioassay. The program also calculates the amount of stock solution to add to each container, in a static bioassay, in order to obtain the desired test concentration. The program will run unaltered on Apple II computers and should be easily modified to run on most other microcomputers using a similar version of BASIC.     

A simple omnidirectional sensor for wind-tunnel studies of pedestrian-level winds

A new sensor for measuring pedestrian-level winds in wind-tunnel models is described. It is axisymmetric about a vertical axis and outputs a pressure difference that is related to the wind speed at a chosen reference height just above the surface. Because of its axisymmetry it requires no alignment with the flow direction. Its calibration is described and it is compared with simultaneously measured hot-wire data in conditions representative of the pedestrian environment. It is found that it can be used to measure both the mean wind speed and the lower-frequency fluctuations in pedestrian wind-studies. Because of its simplicity, it can be installed in large numbers on a model and is well suited for use with automated Scanivalve equipment. The sensor may also be used as an omnidirectional skin friction meter if so desired.     

A sensitivity analysis method for water distribution system tank siting for energy savings

Energy savings in water distribution system (WDS) pumping can save the municipality money and reduce the amount of greenhouse gas emissions. A straightforward method is introduced here that allows any WDS manager to determine source-tank location and connectivity that minimizes pumping energy usage. The method is demonstrated on twelve diverse WDSs to investigate whether less pumping energy is used by having the tank at four key locations. It was found that the new method worked well and identified that having the tank near to the system and connected directly to the source saves pumping energy in all of the WDSs analyzed. If the initial cost of relocating the tank for existing systems or locating the tank near to the source in new systems is less than the cost of energy savings over the lifetime of the tank, then having the tank near to the source is financially worth it.     

辐流沉淀池混凝剂投加参照曲线的绘制及应用

根据辐流沉淀池近三年的单池负荷、原水浊度以及混凝剂投加量数据,绘制了混凝剂投加量与浊度、单池负荷之间的曲线关系图,并介绍了混凝剂投加曲线的应用,以期对现实生产起指导作用。     

液化石油气储罐被动防火系统

为什么说仅有主动的系统是不够的 ,我们在确保被动防火系统火灾前耐久性方面能做些什么。最新的研究成果显示了 :在发生火灾时 ,仅靠安装在液化石油气储罐上的雨淋灭火系统不能很好地完成灭火。雨淋灭火系统被设计成能够用一个稳定的冷却水流完全灌润着火设备。为了使该系统能适当地运行 ,系统必须迅速浇灌着火储罐的外壳 ,保持整个外表面湿润 ,直到消防队能够到达扑灭火灾。在此危急时刻 ,任何一个干燥的储罐外表面都有可能被高温融化和发生破裂。因为储罐外表面温度在 5 min内就能迅速飙升到 2 0 0 0 。根据诸多报道 ,雨淋灭火系统工作过…     

某黑色金属熔炼炉循环冷却水系统设计

介绍了某特殊行业废旧污染黑色金属熔炼处理中心的中频无心感应熔炼炉循环冷却水系统设计,针对工程所在地的气候条件及水质等确定循环冷却水系统的工艺流程、运行控制方式,并结合现场实际运行情况对运行及处理效果进行了评价和分析,得出了一些有参考价值的结论。     

A simple continuous-flow toxicant delivery system

This paper describes a simple continuous-flow toxicant delivery system for use in testing toxicity of dissolved or suspended compounds to aquatic organisms. Its advantages are simplicty, ease of construction, and capacity for high flow rates. The system consists of a glass headbox and diluter box, a toxicant pump, a framework for support, and a system of tubes to deliver a series of toxicant concentrations to the test aquaria. Methods are given for construction and for calibration of the system.     

以育苗废水作热源的海水热泵制热性能研究

以新鲜海水和育苗废水作热源,研究了海水热泵的制热性能和对育苗水体的升温效果。结果表明:增加海水热源温度和流量,有利于提高海水热泵的蒸发温度和制热量,当海水热源温度和流量保持在16℃和300 L/h以上时,海水热泵具有良好的制热性能,热泵的制热系数COP值超过3.5;提高海水热源温度,冷凝器出水升温幅度随之增加,但是随着海水热源流量增大,冷凝器出水升温幅度明显下降,当海水热源温度高于16℃、流量小于300 L/h时,冷凝器出水升温幅度保持在5.8℃以上;利用净化后的育苗废水(温度为21～23℃,流量为300 L/h)作热源时,海水热泵具有良好的运转性能,热泵的COP值达到4.2,冷凝器出水升温幅度达7.6℃,海水热泵的水体升温费用与燃煤锅炉相当,仅为燃气锅炉、电加热和燃油锅炉加热费用的14.5%、23.7%和28.5%。     

雨淋喷水灭火系统设置屋顶水箱的探讨

本文叙述了雨淋喷水灭火系统的组成及规范中对设置消防水箱所存在的问题,通过实际应用说明了应合理选择增压设施.