Optical investigation of fast pulsed discharge on surface of ceramics for environmental applications
Pulsed surface discharge on the surface of ceramics was investigated experimentally. Photon counting method was applied to clarify preceding phase of the discharges. The results indicated the effect of charge injection from electrodes. Pulsed surface discharge reactor for decomposition of nitrogen oxides utilizing honeycomb ceramics was proposed. Framing and streak observation was carried out with image converter cameras. Emission spectra from the discharge were investigated with spectrometer. Uniform surface discharges on honeycomb ceramics were successfully obtained utilizing pulsed power generator with a SI-thyristor.
Manufacturing of anodic porous alumina for barriers in a dielectric barrier discharge reactor
Abstract The simultaneous treatment of gaseous pollutants and suspended particulate matter exhausted from a diesel engine is one of the most serious problems in our living environment. A dielectric barrier discharge (DBD) reactor, which is one of the non-thermal plasma generators, skillfully combined with porous ceramics and/or catalysts is very attractive for the simultaneous treatment. In this study, anodic porous alumina, which has many pores with nanometer-order diameter and high aspect ratio, has been focused as the barrier of a DBD reactor. However, there have been a few reports on the DBD using the anodic porous alumina barrier. In this paper, the anodizing conditions were optimized from a view point of the stable DBD generation in atmospheric pressure air, using only anodic porous alumina as the barrier. A 99.99% pure Al substrate was anodized under a constant voltage condition in sulfuric acid solution. As a result, it was found that the anodic porous alumina with a film thickness between 150 μm and 220 μm, prepared in 1.0 M sulfuric acid at 10 °C, is suitable for the barrier of the DBD reactor, and the stable DBD can be generated in atmospheric pressure air using it.
EFFECT OF SAMPLE PREPARATION ON WATER TREE RESISTANCE OF XLPE/SEBS BLENDS
The effects of an aromatic polymer, such as poly[styrene-b-(ethylene-co-butylene)b-styrene] (SEBS), and its preparation processes on water tree resistance, morphology, crystallinity, dielectric constant and dielectric loss tangent of crosslinked polyethylene (XLPE)/SEBS and XLPE/SEBS/ethylene vinyl acetate (EVA) blends were investigated. The XLPE/SEBS samples were characterized by means of differential scanning calorimetry, scanning electron microscopy, dielectric spectral analysis and the accelerated water treeing experiment. The results clearly showed that although SEBS was partially compatible with LDPE and it was dispersed evenly in XLPE matrix, the blends demonstrated excellent dielectric performances, such as dielectric constant and dissipation factor. The crystallinity of XLPE/SEBS blends was decreased with increase in SEBS content and it was further decreased with the addition of EVA. SEBS could effectively improve the water-tree resistance of XLPE and both SEBS and EVA were found to improve the water tree resistance of XLPE synergistically as expected. The differences in sample preparation processes could change the phase morphology and dielectric performance of the blends, and could also influence the dispersion of SEBS in XLPE matrix as well as the crystallinity of the blends. Different preparation processes led to different water tree resistance behaviours of the samples. The improvement of SEBS dispersion in XLPE matrix helped to improve the water tree resistance of XLPE.