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This paper was arranged a polymer cylinder around a Cu fuse‐element to increase both an arc resistance rarc$$ {r}_{\mathrm{arc}} $$ during a DC arc quenching process and an insulation resistance Rins$$ {R}_{\mathrm{ins}} $$ after the DC arc quenching. The used polymer cylinder equips a narrow‐section with a width wP$$ {w}_{\mathrm{P}} $$ made from the polymer. A position of the narrow‐section was around an arc‐ignition point of the Cu fuse‐element. Silica‐sand (SiO2‐sand) was filled inside the polymer cylinder. Then, a damping DC with a prospective peak of 1000 A was energized to the Cu fuse‐element. As an experimental result, rarc$$ {r}_{\mathrm{arc}} $$ was successfully increased with wP$$ {w}_{\mathrm{P}} $$ of the narrow‐section. In addition, the rise in wP$$ {w}_{\mathrm{P}} $$ of the narrow‐section also increased Rins$$ {R}_{\mathrm{ins}} $$ to more than 10 MΩ$$ \mathrm{M}\Omega $$ under the DC 1000 V application after the arc quenching. In order to interpret rarc$$ {r}_{\mathrm{arc}} $$ rise and high Rins$$ {R}_{\mathrm{ins}} $$ under the polymer cylinder arrangement, chemical composition, an electrical resistivity ρ$$ \rho $$, and a thermal diffusivity α$$ \alpha $$ of Cu/SiO2/Polymer vapor mixture was also calculated. Based on the experimental result and calculation result, rarc$$ {r}_{\mathrm{arc}} $$ rise can be interpreted based on rise in ρ$$ \rho $$ and α$$ \alpha $$ due to the polymer vapor admixing into Cu/SiO2 vapor mixture. In addition, increasing Rins$$ {R}_{\mathrm{ins}} $$ can also be interpreted by the polymer ablation of the narrow‐section of the cylinder. The results are useful to further increase the interruption capacity of the DC fuse. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Anthropogenic particles in sea surface water of the semi-enclosed Osaka Bay were identified using stereomicroscopy, classified according to polymer type using Fourier-transform infrared spectroscopy (FTIR), and categorized according to their physical characteristics. A total of 565.1 particles were detected in the water samples. However, plastic particles accounted for only 22.4% of the particles. Microplastic abundance in Osaka Bay showed seasonal variance from 8.9 ± 1.4 (in May) to 22.8 ± 6.5 particles/L (in July), which is consistent with previous reports in other semi-enclosed bays. Microplastics were mainly fragmented and fiber shaped, with gray and colorless/white coloration. The dominant polymer types were polypropylene, poly(methylmethacrylate), polyester, polyethylene, and polyethylene terephthalate. Generally, there were considerably higher abundances of microplastics at offshore sites compared with nearshore sites. The results of this study suggest that local river effluents and marine-related activities are probable sources of microplastics in Osaka Bay., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Concerning DC arc quenching phenomenon in silica sand filling space, we have proposed a new method for raising an arc column resistance (rcol) by use of polymer‐material arrangement. This paper reveals physical factors for rcol rise on the bases of experimental results using the following cylinders made of: (i) Quartz (SiO2) and (ii) PMMA ((C5H8O2)n) with various inner diameters ϕ. For ϕ = 2 mm case, rcol measured for a PMMA cylinder arrangement indicated higher rcol at low current region, while almost same rcol around current peak. For ϕ = 3 mm case, rcol for the PMMA cylinder was lower than rcol for the quartz case at high current region, while almost comparable between these conditions at low current region. For ϕ = 5 mm case, rcol were almost same during the arc quenching process. To discuss the effect of the rcol rise, the followings were also performed: (i) observation of cylinders after arc quenching and (ii) calculation of the electron density of SiO2/Cu or PMMA/SiO2 mixture vapors. It is concluded that, at high current region, rcol can increase due to the shrinking of the arc conductive diameter caused by the cylinder hole and the silica sand filled inside the cylinder hole. On the other hand, the admixing of the PMMA ablation vapor increases rcol at low current region in the present experiment. © 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

In this study, experiments pertaining to direct current (DC) interruptions are performed in an arc‐quenching chamber filled with silica sand. First, the arc column resistance is measured during DC arc‐quenching to demonstrate the elementary aspects of the arc in the silica‐sand‐filled space. Subsequently, an arrangement comprising a polymer cylinder between electrodes in the silica‐sand‐filled space is proposed to increase the arc column resistance during DC arc‐quenching. A polymethyl methacrylate (PMMA) cylinder is used in the experiments. Measurement results indicate that the arrangement of the PMMA cylinder causes the arc column resistance to increase approximately twofold in comparison with the no‐PMMA cylinder arrangement. Finally, the effect of increasing the arc column resistance is discussed in terms of PMMA and silica vapor. © 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Thermal degradation was performed at 175, 200, and 250 °C from 100 to 2000 h on flame‐retardant ethylene propylene rubber (FR‐EPR) with the same compositions as those used in the insulation of a safety‐related cable in nuclear power plants. For these samples, indenter modulus (IM), elongation at break, tensile strength, and complex permittivity were measured to clarify mechanical and dielectric properties. Fourier transform infrared absorption and differential scanning calorimetric spectra were also measured to determine structural changes. As a result, it was found that FR‐EPR becomes hard by oxidation and crosslinking, and that it becomes brittle as the degradation becomes more severe. In addition, such changes in mechanical properties by the aging occur much earlier than the changes in dielectric properties. Regarding this, IM is a good indicator to examine the degradation degree of FR‐EPR. © 2020 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [ABSTRACT FROM AUTHOR]

Background: A double-network (DN) gel, which was composed of poly-(2-acrylamido-2-methylpropanesulfonic acid) and poly-(N,N′-dimetyl acrylamide) (PAMPS/PDMAAm), has the potential to induce chondrogenesis both in vitro and in vivo.Purpose: To establish the efficacy of a therapeutic strategy for an articular cartilage defect using a DN gel.Study Design: Controlled laboratory study.Methods: A 4.3-mm-diameter osteochondral defect was created in rabbit trochlea. A DN gel plug was implanted into the defect of the right knee so that a defect 2 mm in depth remained after surgery. An untreated defect of the left knee provided control data. The osteochondral defects created were examined by histological and immunohistochemical evaluations, surface assessment using confocal laser scanning microscopy, and real-time polymerase chain reaction (PCR) analysis at 4 and 12 weeks. Samples were quantitatively evaluated with 2 scoring systems reported by Wayne et al and O’Driscoll et al.Results: The DN gel–implanted defect was filled with a sufficient volume of the hyaline cartilage tissue rich in proteoglycan and type 2 collagen. Quantitative evaluation using the grading scales revealed a significantly higher score in the DN gel–implanted defects compared with the untreated control at each period (P < .0001). The mean relative values of type 2 collagen mRNAs in the regenerated tissue were obviously higher in the DN gel–implanted defect than in the untreated control at each period. The mean surface roughness of the untreated control was significantly higher than the normal cartilage at 12 weeks (P = .0106), while there was no statistical difference between the DN gel–implanted and normal knees.Conclusion: This study using the mature rabbit femoral trochlea osteochondral defect model demonstrated that DN gel implantation is an effective treatment to induce cartilage regeneration in vivo without any cultured cells or mammalian-derived scaffolds.Clinical Relevance: This study has prompted us to develop a potential innovative strategy to repair cartilage lesions in the field of joint surgery. [ABSTRACT FROM AUTHOR]

In Japan, the most common illicit drug is methamphetamine. It is possible to trace the origin of this drug by analyzing its organic and inorganic impurities and/or byproducts using several methods, such as GC, GC/MS, and inductively coupled plasma-mass spectrometry (ICP-MS). As reported here, one other method includes comparison of the striation lines of polymer sheet layers from packaging using a polarized light method. Other alternative methods include analyzing the heat sealer pattern, layer thickness surface characteristics, and/or components of polymer sheet layers using infrared spectroscopy. Several of these alternative methods were used to analyze the origins of 29 packages confiscated from three regions over a 1000 km distance in Japan. Results indicated that packages seized from different regions had some polymer sheet layers which contained striation lines and heat sealer patterns that were similar. [ABSTRACT FROM AUTHOR]

Respirable organic chemicals were originally thought to cause allergic respiratory diseases, such as bronchial asthma and hypersensitivity pneumonitis, and believed not to cause lung disorders derived from inflammatory or fibrotic processes such as pulmonary fibrosis and interstitial pneumonitis. It has recently been reported, however, that exposure to organic chemicals can cause interstitial lung diseases. In this review, we discuss the clinical features of occupational asthma and hypersensitivity pneumonitis, as well as other lung disorders, including interstitial pneumonitis, caused by humidifier disinfectants in Korea and by a cross-linked acrylic acid-based polymer (CL-PAA) in Japan., (© 2021 The Authors. Journal of Occupational Health published by John Wiley & Sons Australia, Ltd on behalf of The Japan Society for Occupational Health.)