Ziele und Methoden der elektrochemischen Verfahrens- und Reaktionstechnik

Objectives and methods of electrochemical process and reaction engineering . Electrolysis processes are distinguished from ?normal”? chemical processes in several respects: (1) The electrical energy consumed is expensive and assumed the role of an expensive raw material. (2) Mass transfer in electrolytes is sluggish and limits space time yield to relative low values. (3) The rate of reaction is dictated by the applied electrode potential and this determines the cell voltage and energy efficiency of electrolysis processes. Effective electrocatalysts diminish energy consumption per unit mass of product. (4) The relatively poor electrical conductivity of electrolytes leads to construction of special closely spaced cells with narrow cell gaps. It is important to select the operation conditions of, e. g. organo-electrosyntheses to minimise the efforts involved in isolation and purification of the product.     

What Happens during Thermal Post-Treatment of Powder Aerosol Deposited Functional Ceramic Films? Explanations Based on an Experiment-Enhanced Literature Survey

Powder aerosol deposition (PAD) is a unique ceramic spray coating method that produces dense and well-adhering thick-films directly at room temperature, without requiring any heating or sintering. After the successful film formation, mechanical film properties like hardness or plasma resistance are remarkably good. However, when it comes to electrical properties like permittivity or electrical conductivity, the nanocrystalline structure of PAD films combined with high internal strains deteriorates partly the characteristic properties. The electrical conductivity may already be present within the as-deposited films. However, it is mostly lowered by several orders of magnitude. Therefore, a thermal post-deposition annealing is oftentimes required. In this work, electrically conducting films produced by powder aerosol deposition are surveyed based on published data. Their microstructural and electrical behavior during the post-deposition annealing treatment is summarized and reasons for the lowered electrical conductivity are identified. Additionally, the processes taking place during annealing, which eventually allow to regain bulk-like functional properties, are examined. A universal annealing behavior is found that leads to a quantitative recommendation for the suitable film annealing temperatures to regain the electrical conductivities.     

工业配电网经中性点低电阻接地改进后的运行状况

1初始状况Volkswagenwerk AG经营管理着一个6 kV系统向它的Emden工厂提供电力。该电力系统按两个在电气上各自独立的子系统运行,每个子系统以两台110/6 kV变压器供电。从变电所和6 kV开关室经一路短电缆馈线供两台6/0.4 kV变压器。在备用情况时,这路短电缆馈线可从对端经备用电缆供电。6 kV开关室由两条电缆供电。从变电所和开关室的馈出线路上都有过电流时间继电器保护。馈入线路的电流互感器额定值为2 500/5 A,供电电缆上为1 000/5 A,其余馈出线路上为300/5 A或400/5 A。工厂装用的过电流时间继电器是老式的电气机械和模拟电子式的…