Dropwise Condensation Heat Transfer Coefficient on the Horizontal Circular Surface with Radial Gradient Surface Energy

A theoretical model is developed for the dropwise condensation heat transfer on the horizontal circular surface with radial gradient surface energy based on the heat transfer model of individual condensate drop and the size distribution model of condensate drop on homogeneous condensation surface.The effect of variation of contact angle on the gradient surface on condensation heat transfer and condensate drop size distribution is taken account of in this model.The theoretical calculation method was obtained to predict the dropwise condensation heat transfer coefficient on the horizontal circular surface with radial gradient surface energy under various wall subcooled temperature,contact angle profile on wall surface,and working fluid.The effects of surface energy gradient,wall subcooled temperature,and thermophysical properties of condensate on the condensation heat transfer are discussed respectively.The calculation results show that the condensation heat transfer coefficient increases slightly with the increase of wall subcooled temperature.As latent heat and surface tension increasing,the condensation heat transfer coefficient increases.A larger surface energy gradient induces a larger condensation heat transfer coefficient.     

Design for Precision Measurement System Based on Machine Vision

It is difficult to measure the geometric quantity of small parts in finishing, assembling and measuring, because it's easy to break the workpieces' surface and alter their position by means of traditional contact measuring methods.There are some non contact measurers, such as,light feeler pin and interference microscope etc., because of it's high price and strict working conditions,so it's difficult to promote them in widely use. Precision measurement system based on machine vision has the advantages of non contact measuring as well as high performance and low price. Some problems, such as light source, algorithm of edge fitting, auto focusing,are discussed.     

Penetration behavior of bath induced by top-blown gas jets for steelmaking converter

The cavity induced by top-blow gas jets impinging on the bath surface is one of most important parameters, which has overwhelming influence on the rate of slag formation and metallurgical performance. Water model experiments are conducted through a 1/10 scaled-down top-blown convertor. Effects of lance height and gas flow rate on penetration behavior are studied, and also the influence mechanism of liquid surface tension on penetration depth is addressed based on the experiments and theory analysis. An energy utilization index (EUI) is defined to reflect how much the impinging kinetic energy of gas jets are transferred into bath for formation of cavity, and an improved model is proposed to predict penetration depth of jets. The results show that penetration depth increases with lowering lance height and increasing gas flow rate, and impact diameter increases with increasing lance height, but is little affected by gas flow rate. Influence of liquid surface tension on penetration depth is enhanced with increasing surface tension and penetration depth. The EUI increases with increasing lance height, and a function relationship of it with lance height is obtained based on the experiments.     

Existing Situation on Disposal of Sludge from Wastewater Treatment Plant in Three-Gorges Reservoir Area

At present 18 wastewater treatment plants operateing in the Small towns of Three Gorge Areas of Chongqing Municipality, producing 132.95 tons surplus sludge everyday. As regards to the disposition of such numerous surplus sludge, the major disposition technique in these wastewater water treatment plants, i. e. , thickening and mechanical dewatering technique followed by feeding into the municipal solid waste landfill, seems to have a rather bad effect on the normal operation of the municipal solid waste landfill, due to the unstabilized sludge resulted from this technique of the sludge disposition and high moisture in the sludge, which is higher than 80%. This paper has paid some attention to this phenomenon. With respect to the small towns having the the municipal solid waste landfill, the techniques of mechanical dewatering, calcareousness stabilized etc. before feeding into the municipal solid waste landfill, seem to be feasible, while the composting and comprehensive utilization of sludge is available in the small towns which have no municipal solid waste landfills.     

60Co-γ射线辐照处理对天竺葵、观赏椒种子发芽率及幼苗的影响

用60Co-γ射线辐照处理天竺葵、观赏椒种子,观察其发芽率和幼苗生长情况.结果表明:γ射线辐射对这2种观赏植物的发芽率和幼苗生长发育具有不同的影响.对天竺葵的发芽率有促进作用,但抑制幼苗生长;对观赏椒发芽率作用不显著,对幼苗前期生长有抑制作用.     

三江平原井灌水稻区地下水人工补给方法初探

针对三江平原井灌区地下水位逐渐下降、急需恢复的现状,结合国内外地下水人工补给实践,对三江平原井灌区地下水人工补给方法进行了探讨,提出了今后地下水人工补给实践的初步设想,为该区域地下水资源的可持续利用提供了参考依据.     

隔膜计量泵的改良设计与汽蚀性能的提高

针对应用于石油化工装置上的进口隔膜计量泵容易产生的汽蚀问题，对隔膜泵复合隔膜、柱塞密封副、液压平衡与补偿阀结构进行了改良设计，采用较大承载能力的机座、独特阶梯式活塞、加大直径的活塞、PTFE＋NBR复合隔膜，改良放气安全阀及油浸没式补偿系统等方法，提高了隔膜计量泵的汽蚀性能；通过对改造的隔膜计量泵与原有的计量泵进行的汽蚀试验对比，给出了隔膜计量泵性能与现场使用的最佳匹配工况。改良的结构设计和新型材料的选用大大提高了计量泵的汽蚀性能。     

地理信息系统在环境影响评价中的应用

为了研究地理信息系统（GIS）在环境影响评价中的应用，在介绍地理信息系统的组成、类型、功能和应用领域的基础上，分析了GIS技术在环境影响评价中的优势，并结合实例，探讨了地理信息系统在水环境影响评价中的具体应用过程。     

圆盘刀人力割禾器的设计

设计了圆盘刀人力割禾器．其推进只是起到行走和预切割部分茎秆的作用，切割主要由动刀旋转来完成。设计的动、定刀片皆为齿刀，且皆可自磨锐，作业时动刀片每个齿都参与切割，所以磨损较均匀，切割功率随时间增加反而有所下降，基本解决了原割禾器存在的刀片磨损集中。寿命低的问题。