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The capacitive coupler is an attractive tool for on‐site partial discharge (PD) detection in a cable joint. To study its sensitivity characteristic, PDs in a 110‐kV prefabricated joint containing two artificial defects were detected successively using capacitive couplers with six different electrode widths installed at the same position of the cable. For the quantification of sensor sensitivity, the sensitivity factor is defined as the ratio of capacitive coupler output voltage amplitude to apparent charge that was determined through a conventional PD‐measuring circuit according to IEC 60270. As random variables, the sensitivity factors were displayed in the probability distribution plots for each capacitive coupler to visually compare their sensitivity levels. The results demonstrate an almost monotonically increasing dependence of sensitivity on the coupling electrode width, which agrees with the qualitative analysis based on the amplitude–frequency characteristic of the capacitive coupler. Besides, there is an obvious distinction in sensitivity factors between two distinct defects, indicating that the capacitive coupler is more suitable for PD trend analysis rather than apparent charge quantification. In addition, the insensitivity of the capacitive coupler to certain defect types may explain the cause of some undetectable dead zones in on‐site PD measurement. This study provides experimental support for the geometrical optimization of capacitive couplers. © 2019 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [ABSTRACT FROM AUTHOR]

Introduction: The association of adhesive systems and desensitising agents could influence the values of the bond strength. That is because these desensitising agents cause the obliteration of the tubular holes and minimise the movement of the dentin fluids, promoted by environmental stimulus that tends to cause hydrolysis at the base of the hybrid layer over time. Aim: To evaluate the microtensile bond strength of total-etch (Single Bond II, SB, 3M ESPE, USA) and self-etch (Clearfil SE Bond, SE, Kuraray, Japan) adhesive systems in dentin conditioned after the application of oxalate-based and fluoride-based desensitising agents. Materials and Methods: Discs obtained from human molars were used, which had its occlusal enamel removed to expose flat surfaces of dentin. Six groups were formed, according to the materials used: G1 (control)- hybridization with SB; G2- desensitizer based on oxalate (BisBlock, BB) and SB; G3- desensitizer based on fluoride (Aqua Prep F, AF) and SB; G4 (control)- hybridization with SE; G5- BB and SE; G6- AF and SE. On these surfaces, blocks of composite resin Filtek Z350 of 5 mm high were prepared to obtain sticks of (1x1x10 mm). The samples were stored in deionized water at 37°C for 24h and submitted to microtensile mechanical trial at 1mm/min speed till the fracture. The results were statistically analysed by one-way ANOVA followed by Tukey's post hoc test (p<0.05). results: The mean values of bond strength of the studied groups in MPa (SD) were as follows: G2: 46.48 (4.02), G3: 44.87 (4.68), G5: 39.02 (4.72), G4: 36.95 (3.57), G1: 36.66 (3.42), G6: 32.71 (3.41) which did not show statistically significant differences (p>0.05). Regarding the fractures analysis, the mixed type prevailed. The fracture was on the base region of the hybrid layer for the total- etch adhesive system, and at the top of the hybrid layer for the self-etch system. conclusion: There is no significant difference in bond strength between the combined use of desensitizers with total-etch and self-etch adhesive systems on human dentine. [ABSTRACT FROM AUTHOR]

Abstract: Potentially toxic metals, such as Cu, Pb and Zn, are leached from weathered rocks at many closed mine sites due to the acidic environments and mineralogical modifications. The mobilized toxic metals may cause contamination of surrounding water bodies. In this study, both laboratory column experiments and field observations at a former mine located in the north of Japan were carried out to compare the leaching behavior of Cu, Pb and Zn. The thickness of the surface weathered rock was varied (10, 20 and 30cm) for the columns experiments while porous cups for porewater sampling were set up at different depths (GL-15, -45, -70, and -95cm) for the field observations. Deionized water was added once a week over 75weeks to the columns to simulate rainfall while porewater was extracted by a vacuum pump in several sampling campaigns (over 18months). Similar low pH and leaching behavior of potentially toxic metals were observed for column experiments and field observations. A moderate increase in concentration with depth was observed for Cu and Zn. However, no increase in concentration was observed for Pb. This suggests that the leaching of Cu and Zn is enhanced by the length of the flow pathway through the weathered rock layer while Pb concentration is restricted by the precipitation of insoluble Pb sulfate. Thus, the thickness of the weathered rock layer is an important parameter that should be taken into consideration to estimate the loads of some potentially toxic metals, which is important when designing remediation schemes. [Copyright &y& Elsevier]

Sub-critical water (sub-CW) technology was used as a new technology with environmental and financial benefits for the recovery of harmful heavy metal ions Cd (II), Zn (II), Cu (II), Fe (II), Mn (II) and Ni (II) in the waste of Japanese scallop Patinopecten yessoensis. The metals are responsible for environmental problems owing to the large amount of the waste. This study proposes a new method using sub-CW treatment to recover the metal ions from scallop waste and simultaneously produce harmless and valuable materials. Reactions were conducted in a temperature range of 473–653 K and for reaction times of 1–60 min. After the sub-CW reaction, four phases existed: an oil phase, metal-soap phase, aqueous phase and solid residual. Some oil was hydrolyzed by the sub-CW reaction and converted to free fatty acids and glycerin. Free fatty acids reacted with metal ions and became metal-soap phase. Both the metal-soap phase and oil phase caught almost all metal ions at low and medium reaction temperatures (473–573 K) from original wastes, although the concentrations of the metal ions in the metal-soap phase were much higher than those in the oil phase. With increasing temperature, these two phases decomposed and the metal ions concentrated in solid residual (un-reacted waste). The binding mechanisms in the oil and metal-soap phases are discussed including the key functional groups involved. The maximum concentrations of metal ions in metal-soap phase were 7225 ppm (Fe), 862 ppm (Zn), and 800 ppm (Cd) at 573 K. The aqueous phase showed the lowest concentration of metal ions especially at temperatures above 550 K (∼1.5 ppm). [Copyright &y& Elsevier]