This paper deals with the study of a non-destructive technique to detect the aging state of cable insulation used in a nuclear environment subjected to radiation and temperature aging. Cable samples were aged under dose rates ranging from 0.42 and 1.06 kGy/h at 55 and 85 °C. The imaginary part of the permittivity at 100 kHz is found to correlate well with mechanical properties, such as elongation at break, which is typically used to diagnose cable insulation, but it is a destructive property and cannot be used on field. It has been demonstrated also that a post-irradiation effect occurs even years after aging is stopped, increasing the imaginary permittivity and worsening mechanical properties due to the slow conversion of radicals into oxidized species. The main consequence is that when cable insulation is subjected to a nuclear accident, releasing a huge amount of radiation, the health of cable insulation must be followed also for a long time after the accident occurred, since aging due to oxidation progresses even when the radiation source is switched off.
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http://dx.doi.org/10.3390/polym13040494 | DOI Listing |
Science
January 2025
Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore.
Axions, hypothetical elementary particles that remain undetectable in nature, can arise as quasiparticles in three-dimensional crystals known as axion insulators. Previous implementations of axion insulators have largely been limited to two-dimensional systems, leaving their topological properties in three dimensions unexplored in experiment. Here, we realize an axion insulator in a three-dimensional photonic crystal and probe its topological properties.
View Article and Find Full Text PDFPolymers (Basel)
December 2024
Key Laboratory of Cluster Science of Ministry of Education & School of Chemistry, Beijing Institute of Technology, Beijing 100081, China.
Cross-linked polyethylene (XLPE) is applied in most advanced high-voltage direct-current (HVDC) power cable insulations, which are produced via dicumyl peroxide (DCP) technology. The electrical conductivity of insulation material can be increased by cross-linking byproducts from the DCP process. Hence, currently much attention is being paid to a new process to produce cross-linking byproduct-free XLPE.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Center for Bioinspired Science and Technology, Hangzhou International Innovation Institute, Beihang University, Hangzhou, 311115.
Achieving multi-spectrum compatible stealth in radar-terahertz-infrared bands with robust performance has great prospects for both military and civilian applications. However, the progress of materials encounters substantial challenges due to the significant variability in frequency coupling properties across different electromagnetic wave bands. Here, this work presents the design of a multi-scale structure and fabricates a lightweight aerogel (silver nanowire@carbon, AgNW@C) consisting of a regular coaxial nano-cable, with silver nanowire as the core and amorphous-graphitized hybrid carbon as the outer-layer.
View Article and Find Full Text PDFSensors (Basel)
November 2024
School of Electrical Engineering, Southwest Jiaotong University, Chengdu 611756, China.
Cable termination is an important part of energy transmission in high-speed trains, and it is also a weak link in the insulation. It is important to determine the insulation status of cable terminals by the detection results of partial discharge signals, but the partial discharge signals in the field test circuit are mixed with a large amount of external corona interference, which affects the detection accuracy. This paper proposes a signal recognition model that incorporates Stockwell transform (ST) and 2DCNN, which in combination with wavelet noise reduction can achieve a high-precision classification effect for partial discharge and corona interference with an accuracy rate of up to 98.
View Article and Find Full Text PDFSensors (Basel)
October 2024
Department of Mechanical Engineering, University of Maryland, Baltimore County, Baltimore, MD 21250, USA.
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