Performance of Hydrophobic Epoxy Insulators under Industrial Pollution

Cycloaliphatic epoxy resins have been used alongside silicones and ceramics for more than 30 years as insulation materials for outdoor applications. Insulators made of cycloaliphatic epoxies offer many advantages overer those made of ceramic or silicones. Standard cycloaliphatic epoxies are construction materials, however, they do not exhibit hydrophobicity as do silicones. A new generation of cycloaliphatic epoxy systems with enhanced hydrophobic properties, hydrophobic cycloaliphatic epoxy try to join the advantages of both cycloaliphatic epoxy resins and silicones The paper presents the laboratory and field test results of comercially available hydrophobic cycloaliphatic epoxy insulators. These insulators exhibit the hydrophobic properties under clean conditions. Unfortunately, when polluted by industrial dust the surface becomes hydrophilic. No hydrophobicity transfer was round even three months after surface contamination. Nevertheless, compared with the standard cycloaliphatic epoxy the hydrophobic cycloaliphatic epoxy offers some advantage under light industrial pollution or sea pollution

Franklin rods - sharp or blunt ?

This paper gives the historical background of 250 year old question: should the Franklin rod tip be sharp or blunt ? The earlier works, the new field results from USA and own laboratory experiments are presented. The switching impulse tests were carried out with two different shapes of high voltage electrodes: rod or sphere and without additional dc bias voltage. In the arrangement with rod as high voltage electrode the smaller breakdown voltages were measured with sharp grounded electrode with negative impulse polarity. At the positive polarity the breakdown voltages do not depend on the shape of grounded electrode. The tests with spherical high voltage electrode showed, that breakdown voltages under negative polarity are practically the same for three different grounded electrodes. In spite of that, the remarkable differences in time to breakdown were noted

Silicone rubber insulators with notched surface

A modification of an insulator profile was proposed and the advantage of a new solution was shown. The pollution flashover voltage of an insulator with small notches is about 25% higher than the flashover voltage of a flat surface. The laboratory and field tests which show the effectiveness of surface modification made on silicone rubber were described. The possibility of further surface optimization was claimed

Temperature monitoring of metal oxide surge arresters

Varistor overtemperature above the ambient is an important state parameter of metal oxide surge arresters. The temperature monitoring using passive SAW sensors enables realisation of a surge counter function, an energy monitor, monitoring of electrical ageing and pollution stress. For temperature measurements during pollution tests of metal oxide arresters the not so advanced, TINY TALK sensors could be used. This method of temperature measurement was also applied in the field for temperature control of arresters tested at the pollution station near Głogów, Poland. The preliminary results during the first year of monitoring are presented and compared with results of similar measurements conducted in Germany close to the seacoast

Application of lightning location systems for fault detection on transmission and distribution lines

The lightning location systems were installed in many countries during last twenty years. The paper presents the SAFIR system called PERUN, which was built in Poland in 2002. The lightning location systems are used for different purposes including among other things meteorology, weather forecasting and aviation. A brief review of fault detection on transmission and distribution lines made abroad and the first experience of the Polish National Grid PSE was shown

Verschmutzungsverhalten von Hochspannungsisolatoren und Ableitern

Von 1980 bis 2005 wurde das Verschmutzungsverhalten unterschiedlicher Hochspannungsisolatoren und Überspannungsableiter im Freiluftprüffeld „Glogów“ untersucht. Fortschritte im Umweltschutz und neue Technologien haben zu einer bedeutenden Abnahme der Staub- und Gasemissionen in der Nähe von Kupferhütten geführt. Als direkte Folge hat sich der Umweltverschmutzungsgrad des Gebiets von vier (sehr hoch) in den 1980er-Jahren auf eins (leicht) im Jahr 2003 reduziert. Die Überschlagspannung von Porzellanisolatoren wurde 1987 unter natürlichen Bedingungen und in den Jahren 2002 bis 2004 nach Befeuchtung mit Spritzwasser gemessen. Ferner wurden die Spannungsfestigkeit von Keramikisolatoren mit der von silikon- bzw. PTFE-beschichteten Isolatoren verglichen und die Messwerte der Innentemperatur von Metalloxid-Überspannungsableitern in einem Keramikgehäuse dargestellt

Výzkumy na jímačích ESE

The paper reviews about research of radioactive lightning rods carried out 30 years ago and about new measurements of early streamer emission terminals. Lightning damage on over 100 buildings equipped with ESE terminals in Malaysia and on one family house in Poland is reported. The main measure criterion was the breakdown voltage of the air gap consisted of the high voltage electrode (rod or plate) and a grounded radioactive or ESE terminal. These careful measurements show that the air gaps with ESE terminals have the same breakdown voltages as the air gaps with standard rods. Therefore the big protection zone of ESE terminals as claimed by their manufactures seem to be impossible

Deterministic Assembly of Arrays of Lithographically Defined WS2 and MoS2 Monolayer Features Directly from Multilayer Sources into Van der Waals Heterostructures

One of the major challenges in the van der Waals (vdW) integration of two-dimensional (2D) materials is achieving high-yield and high-throughput assembly of predefined sequences of monolayers into heterostructure arrays. Mechanical exfoliation has recently been studied as a promising technique to transfer monolayers from a multilayer source synthesized by other techniques, allowing the deposition of a wide variety of 2D materials without exposing the target substrate to harsh synthesis conditions. Although a variety of processes have been developed to exfoliate the 2D materials mechanically from the source and place them deterministically onto a target substrate, they can typically transfer only either a wafer-scale blanket or one small flake at a time with uncontrolled size and shape. Here, we present a method to assemble arrays of lithographically defined monolayer WS2 and MoS2 features from multilayer sources and directly transfer them in a deterministic manner onto target substrates. This exfoliate-align-release process - without the need of an intermediate carrier substrate - is enabled by combining a patterned, gold-mediated exfoliation technique with a new optically transparent, heat-releasable adhesive. WS2/MoS2 vdW heterostructure arrays produced by this method show the expected interlayer exciton between the monolayers. Light-emitting devices using WS2 monolayers were also demonstrated, proving the functionality of the fabricated materials. Our work demonstrates a significant step toward developing mechanical exfoliation as a scalable dry transfer technique for the manufacturing of functional, atomically thin materials

Sex determination based on the analysis of a contemporary Polish population’s palatine bones: a computed tomography study of 1,200 patients

Background: The aims of the present study were to assess whether the hard palate reveals any measurable sex-related differences, and to create a mathematical model which would differentiate between males and females using hard palate measurements alone. Materials and methods: The present study was conducted on 1,200 archived sinus computed tomography (CT) scans. Each cranial measurement was taken twice by the same observer, and in cases of any discrepancies, the mean of the two values was recorded. Twenty per cent of randomly chosen samples were re-measured by an observer who did not partake in assessing the samples the first time. Logistic regression was used to derivate two mathematical formulas which would calculate the probability of a skull being male. Results: The studied group comprised 1,200 head CT’s (627 female; 52.3%). The mean age of the group was 43.5 ± 17.4 years — no age difference between sexes was noted (p = 0.37). All of the performed measurements were significantly (p < 0.0001) larger in males than in females. The mathematical formula based on the “orale-spina nasalis posterior” (O-SNP) distance alone had a reliability rate of 68.35%. The equation based on the depth of the right greater palatine canal (GPC), the O-SNP distance and the anterior width of the palatal arch (AWPA) had a reliability rate of 78.37%. Conclusions: The most prominent sexually dimorphic parameters were the O-SNP, the GPC depth and the AWPA. The mathematical models presented in the current study can be used to successfully distinguish between sexes during forensic examination.

Product attributes important to US adult consumers' use of electronic nicotine delivery systems: A discrete choice experiment

Objective To understand the importance of electronic nicotine delivery systems (ENDS) product attributes to adult consumers in the USA by age and gender. Design Cross-sectional survey with a discrete choice experiment (best-worst, case 2, scaling) of 19 choice tasks in which participants answered what would make them most want to use and least want to use an ENDS product. Setting and participants A national sample of adults (aged 18+ years) in the USA who had tried an ENDS product at least once. Measures We included 9 ENDS attributes with levels that varied across 19 choice tasks. We performed a multinomial logistic regression to obtain overall importance scores, attribute-level part-worth utilities and most important attribute. Results Of 660 participants, 81% were white, 51% women and 37% had at least a 4-year college degree with an average age of 42.0 years (SD ±19.4). The attributes had the following importance: harms of use 17.6%; general effects 14.1%; cessation aid 12.6%; purchase price 12.1%; monthly cost 12.0%; nicotine content 11.4%; flavour availability 8.4%; device design 7.2%; modifiability 4.6%. Harms of use was the most important attribute for all ages and genders (p<0.05); variation in other important attributes existed by age though not by gender. Conclusion This study identified the importance of nine ENDS attributes. Perceived harms of use of ENDS use appeared most important, and modifiability was least important. Variation by consumer group existed, which may allow for targeted interventions to modify ENDS use