Discharge studies in micromegas detectors in a 150 GeV/c pion beam

A detailed study of several Micromegas detectors prototyped for the COMPASS and CLAS12 experiments is presented. Using a 150 GeV/c pion beam, the discharge probability was measured for several detector variants including bulk and non-bulk Micromegas. A detector equipped with an additional GEM foil as pre-amplification stage was also tested. A resistive coating of the readout strips was found to reduce the amplitude of the discharge by at least two orders of magnitude which was below the detection limit of the experimental setup. The effects of the micro-mesh type and material were investigated as well as the influence of the drift gap. Response in the presence of a 1.5 T transverse magnetic field was also studied. The measurements presented were performed during a RD51 beam test period.     

Determination of ionization conditions characterizing the breakdown threshold of a point-plane air interval using fuzzy logic

The objective of this paper is to study the discharge phenomenon for a point-plane air interval using an original fuzzy logic system. Firstly, a physical model based on streamer theory with consideration of the space charge fields due to electrons and positive ions is proposed. To test this model we have calculated the breakdown threshold voltage for a point-plane air interval. The same model is used to determine the discharge steps for different configurations as an inference data base. Secondly, using results obtained by the numerical simulation of the previous model, we have introduced the fuzzy logic technique to predict the breakdown threshold voltage of the same configurations used in the numerical model and make estimation on the insulating state of the air interval. From the comparison of obtained results, we can conclude that they are in accordance with the experimental ones obtained for breakdown discharges in different point-plane air gaps collected from the literature. The proposed study using fuzzy logic technique shows a good performance in the analysis of different discharge steps of the air interval.     

Flow over trapezoidal side weir

In this paper, the hydraulic characteristics of a sharp crested trapezoidal side weir have been experimentally and theoretically investigated. It was found that the DeMarchi coefficient of discharge for a sharp crested trapezoidal side weir in subcritical flow is related to the main channel Froude number, the side slope of weir, ratio of weir height to upstream depth of flow and ratio of weir length to upstream depth of flow. Suitable equations for the discharge coefficient are also obtained.     

Durchsatzverhalten von Hohlkegeldüsen

A semi empirical relationship is proposed for swirl nozzle discharge coefficients. It considers the theoretical background and is matched to an extended own experimental database and to data from manufacturers of industrial nozzles. The equation considers the liquid viscosity and can be used for very different nozzle designs.     

Dimensional Analysis of Detrimental Ozone Generation by Negative Wire-to-Plate Corona Discharge in Both Dry and Humid Air

A semi-empirical equation is derived to provide a correlation between the ozone generation rate of a negative wire-to-plate corona discharge in both dry and humid air and a series of design/operating parameters. A basic correlation is first derived by applying dimensional analysis on negative wire-to-plate corona discharge in dry air. Further development on the basic correlation is carried out by integrating the influence of humidity. The derived equation is validated by previously reported experimental data and numerical model. The new semi-empirical equation is comprehensive and useful in guiding the design/operation of indoor corona devices under actual ambient operating conditions.     

型腔模具主要加工方法浅析

介绍并分析了当前型腔模具主要加工方法，提出选择加工方法的依据。     

Production Of Ozone in an Electrical Discharge Using Inert Gases as Catalysts

The catalytic role of using inert gases to increase the efficiency and lower the power cost of producing ozone (O₃) from high purity oxygen (O₂) in a process incorporating an electrical discharge is demonstrated. Three inert gases (Ar, Ne, He) and N₂ are individually mixed with O₂ and the results presented. The increase in ozone production is partially attributed to the increase in electron density provided by the ionization of the inert gas in the discharge.     

Discharge rate capabilities of alkaline AgCuO2 electrode

A series of AgCuO₂ samples are prepared and tested as alkaline cathode materials for primary batteries. AgCuO₂ discharges via four equivalent-charge reduction processes, the rate capabilities of which are determined. At ambient temperature AgCuO₂ displays superior rate capabilities for the two highest voltage processes. For all samples, the rate capability of the two lower voltage processes is always superior to those at higher voltage. This is due to the electrode intrinsically doping itself with elemental silver during discharge as part of the second reduction process. The electrode compares favourably with commercial electrolytic manganese dioxide but is prone to self-discharge, the kinetics of which are also discussed.     

Discharge Relation for Cutthroat Flume under Free-Flow Condition

A cutthroat flume is commonly used as flow measuring device for open-channel flow due to ease of fabrication and installation. In most of the cases it is difficult to calibrate the flume in the field. Therefore, accurate relation between discharge and upstream head applicable for all sizes of cutthroat flume is needed. Seven different sizes of cutthroat flumes, having different length to throat width ratios, are fabricated and tested in the laboratory under free-flow condition. Selecting groups of different variables describing flow through a cutthroat flume number of dimensionless parameters are formed. Regression analysis of experimental data is carried out between all possible combinations of pairs of dimensionless parameters and the pair giving the best correlation is selected. Using the selected pair, relation between dimensionless parameters of discharge and head is developed. The relation is simple and convenient to use and, at the same time, more accurate compared to methods available in literature for prediction of discharge.     

A-O法生物脱氮技术在蒸氨废水中的应用

为解决外排焦化污水中COD和氨氮的超标问题，在对蒸氨系统进行改造的同时，将生化处理装置与A－O法生物脱氮工艺相结合，使外排废水全面达标排放。