T. Kuroyagi's research while affiliated with Electric Power Research Institute and other places

... Meanwhile, the presence of pollutants can increase the increase in the distribution of the local electric field to be non-uniform so that the surface current density (J s ) becomes large because it makes it easier for the charge (Qs) to be ionized in the air-solid dielectric boundary of the epoxy resin. This wet impurity also reduces the surface resistivity (s) so that the surface conductivity (Qs) increases significantly [9][10]. Figure 2 , it can be seen that the heating caused by the leakage current of the impurity (pollutant resistance) increases the temperature of the coating. ...

... environmental parameters [4]. If proper cleanliness is not maintained this pollutants try to degrades the quality of insulator and gradually life cycle of insulators [5]. ...

... Furthermore, these methods of measurement cannot discover insulator strength which causing a loss of isolation state of contaminated insulator in time, need to time to done. Leakage current measurement process of polluted insulators has many features are: fast in time, take to account ambient conditions such as humidity, temperature, drought and rain, and measured wirelessly by sensors or measure the ground line using shunt resistance [3]. Parameters of the leakage current were used as guide to insulators situation from many researchers [4]- [5]. ...

... Because of its excellent electrical insulation, weather resistance, corona resistance and other properties, silicone rubber is widely used as an insulating material in power systems [1][2][3][4]. Fluorosilicone rubber material, with its stable structure and excellent performance, has been used increasingly as an electrical insulation material in harsh environment areas [5][6][7][8]. In these regions, extreme temperatures in winter can be as low as −59 • C and such low temperatures can last for a long time [9][10][11][12]. ...

... For all samples, the TGA curves obtained their weight loss at a temperature of 500˚C tended to decrease of 89% for the virgin sample, 79% for the samples after ageing 60 h and 70% for the samples after ageing 120 h. This result indicates that the weight loss of the samples after the accelerated ageing process was slightly higher than the virgin sample, according to comparison of TGA curves for the virgin and aged silicone rubber material caused by depolymerisation of the siloxane matrix during the ageing process [245]. The weight loss rate of silicone elastomer can be divided into three main phases of temperature, which consisted of the low molecular weight silicone at 310˚C, the maximum weight loss due to decomposition of the crosslinked silicone elastomer at 450˚C and the formation of the silica glass, including loss of carbon on the bulk of molecular structures between 630˚C and 670˚C [246]. ...

... A FTER about 7 years of aging at the Millstone NGS on the Connecticut coast, the RTV silicone coatings on station post insulators have depolymerized substantially resulting in conversion of low molecular weight (LMW) PDMS ( to 15 DMS units) to to 5 units, which are of such low molecular weight that they are volatile and much more easily washed off the surface (Fig. 1).Fig. 2 shows the mass spectrum of LMW PDMS components with 3, 4, and 5 PDMS units which indicate that these components are primarily cyclic in nature [1]. The recent measurements in [2] confirm this finding. ...

... In Figure 2a, two parameters are presented: mass rise after the swelling process, which is proportional to the number of bonds created between different macromolecules, and mass loss during the swelling process, which is proportional to the amount of low molecular weight particles washed out in the swollen state [52]. Thus, it may be concluded that δ-TF and QU did not affect cross-linking density in a significant way as the samples are swollen similarly to the reference ENR/PLA blend. ...

... Conventionally, in rubber processing technology, dispersing aids such as petroleum-and silicon-based oils have been used to help the dispersion of filler and additive during milling and mixing processes of rubber [24][25][26][27][28][29]. The addition of dispersing aids enhances the chains mobility by lowering the cohesive forces between the polymer chains, and simultaneously improve deformability and flexibility of rubber processing in any circumstances. ...

... In order for a surface to be superhydrophobic, it should have a water contact angle of 150 • or greater [6,7]. Silicone rubber (SR) as a polymer has a high hydrophobicity due to an inorganic backbone of Si-O that attaches to the organic groups (frequently methyl) [8][9][10][11]. SR is commonly used in many fields such as fabrication of electrical insulators [12], biomedicine, machinery, electronics and food processing [13] due to its excellent resistance, low toxicity [14], super transparency, high thermal stability [15], and hydrophobicity. ...

... No Japão, Izumi destaca a necessidade do desenvolvimento de linhas compactas de transmissão em ambientes urbanos para acompanhar o crescimento da demanda de energia elétrica, levando à fabricação de isoladores poliméricos em 154 kV para aplicação tipo braced post já no final da década de 1990 [18], sendo outro exemplo de mísula isolante, também descrito por Toya já na década de 2000 [19]. ...