The demand for dielectric capacitors with higher energy-storage capability is increasing for power electronic devices due to the rapid development of electronic industry. Existing dielectrics for high-energy-storage capacitors and potential new capacitor technologies are reviewed toward realizing these goals. Various dielectric materials with desirable permittivity and dielectric breakdown strength potentially meeting the device requirements are discussed. However, some significant limitations for current dielectrics can be ascribed to their low permittivity, low breakdown strength, and high hysteresis loss, which will decrease their energy density and efficiency. Thus, the implementation of dielectric materials for high-energy-density applications requires the comprehensive understanding of both the materials design and processing. The optimization of high-energy-storage dielectrics will have far-reaching impacts on the sustainable energy and will be an important research topic in the near future.

Homogeneous/Inhomogeneous-Structured Dielectrics and their Energy-Storage Performances.

Fusion materials research started in the early 1970s following the observation of the degradation of irradiated materials used in the first commercial fission reactors. The technological challenges of fusion energy are intimately linked with the availability of suitable materials capable of reliably withstanding the extremely severe operational conditions of fusion reactors. Although fission and fusion materials exhibit common features, fusion materials research is broader. The harder mono-energetic spectrum associated with the deuterium–tritium fusion neutrons (14.1 MeV compared to <2 MeV on average for fission neutrons) releases significant amounts of hydrogen and helium as transmutation products that might lead to a (at present undetermined) degradation of structural materials after a few years of operation. Overcoming the historical lack of a fusion-relevant neutron source for materials testing is an essential pending step in fusion roadmaps. Structural materials development, together with research on functional materials capable of sustaining unprecedented power densities during plasma operation in a fusion reactor, have been the subject of decades of worldwide research efforts underpinning the present maturity of the fusion materials research programme. For achieving proper safety and efficiency of future fusion power plants, low-activation materials able to withstand the extreme fusion conditions are needed. Here, the irradiation physics at play and fusion materials research is reviewed.

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Materials research for fusion

In order to support the operation of ITER and the planned experimental programme an extensive set of plasma and first wall measurements will be required. The number and type of required measurements will be similar to those made on the present-day large tokamaks while the specification of the measurements—time and spatial resolutions, etc—will in some cases be more stringent. Many of the measurements will be used in the real time control of the plasma driving a requirement for very high reliability in the systems (diagnostics) that provide the measurements. The implementation of diagnostic systems on ITER is a substantial challenge. Because of the harsh environment (high levels of neutron and gamma fluxes, neutron heating, particle bombardment) diagnostic system selection and design has to cope with a range of phenomena not previously encountered in diagnostic design. Extensive design and R&D is needed to prepare the systems. In some cases the environmental difficulties are so severe that new diagnostic techniques are required. a Author to whom any correspondence should be addressed.

https://iopscience.iop.org/article/10.1088/0029-5515/47/6/S07/pdf

Chapter 7: Diagnostics

A status report on delamination resistance testing of polymer-matrix composites

Progressive damage and delamination in plain weave S-2 glass/SC-15 composites under quasi-static punch-shear loading

Two experimental methods for determining the inter-laminar shear strength (ILSS), are compared: the short-beam-shear (SBS) and the double-lap-shear (DLS) test method. Specimens with a constant ply angle for all layers are considered. The experimental results show a significant difference (up to 50%) in the obtained ILSS. A finite element analysis shows that both test methods underestimate the real ILSS and demonstrate that the standardized ILSS evaluation procedures are more or less valid for the SBS test, but require modifications in the case of the DLS test. Acoustic emission measurements and numerical investigations were performed to determine the real ILSS from the DLS results. The real ILSS cannot be obtained from the SBS test without an extended analysis. It is, however, possible to determine bounds for the real ILSS from the SBS results.

A study of short-beam-shear and double-lap-shear specimens of glass fabric/epoxy composites

https://publik.tuwien.ac.at/files/PubDat_185552.pdf

Karl Humer

Papers

A study of short-beam-shear and double-lap-shear specimens of glass fabric/epoxy composites

Characterization of advanced cyanate ester/epoxy insulation systems before and after reactor irradiation

Novel radiation-resistant insulation systems for fusion magnets

Mechanical behavior of the ITER TF model coil ground insulation system after reactor irradiation

Mechanical properties and fracture behaviour of polyimide (SINTIMID) at cryogenic temperatures