•Ionizing radiation can initiate a variety of chemical (crosslinking and chain scission (degradation)) reactions in polymer materials.•Irradiation processing through the regulation of absorbed dosage ...under various chemical and environmental conditions can modify PET structure.•PET structure is susceptible to modification via chain scission reactions and forming new chemical bonds resulting in different properties for various applications.•PET undergoes a yellowish color change after absorbing irradiation because of the increase in conjugation bonds.
Ionizing radiation can initiate a variety of chemical reactions under any circumstances without applying catalysts in polymer materials. It can be applied intentionally to modify polymeric materials by inducing chemical reactions like chain scission, crosslinking, and structural transformation. This review presents the effect of various irradiation processes on the chemical structure, physical and mechanical properties of poly(ethylene terephthalate) (PET) including electron beam, gamma, ultraviolet, ion beam, and laser irradiation. Generally, the PET structure is susceptible to modification via chain scission reactions and eventually the cleavage of ester and methylene groups. New chemical bonds including polar functional groups like hydroxyl and carboxylic acid groups as well as conjugated bonds can also form. In addition, the PET mesostructure can transform under irradiation resulting in different crystalline arrangements. Therefore, irradiation processing through the regulation of absorbed dosage can modify PET structure to provide different optical, physical, and mechanical properties for various applications.
Co sub(3)O sub(4) quantum dots were synthesized by a facile reverse micelle method for the first time, and were capable of splitting pure water into O sub(2) and H sub(2) stoichiometrically under ...visible-light irradiation ( lambda > 420 nm) without any cocatalyst.
This book consists of original and review papers which describe basic and applied studies for the modifications of metallic and inorganic materials by using energetic ion/electron beams. When ...materials are irradiated with energetic charged particles (ions /electrons), their energies are transferred to electrons and atoms in materials, and the lattice structures of the materials are largely changed to metastable or non-thermal-equilibrium states, modifying several physical properties. Such phenomena will engage the interest of researchers as a basic science, and can also be used as promising tools for adding new functionalities to existing materials and for the development of novel materials. The papers in this book cover the ion/electron-beam-induced modifications of several properties (optical, electronic, magnetic, mechanical, and chemical properties) and lattice structures. This book will, therefore, be useful for many scientists and engineers who have been involved in fundamental material science and the industrial applications of metallic and inorganic materials.
Fabrication of nuclear reactor components using additive manufacturing (AM) methods is now a practical option since the AM technologies have advanced to allow for building of complex parts with high ...quality materials. To assess the mechanical performance of printed components in reactor-relevant conditions and to build a property database for the AM 316L stainless steel (SS), mechanical testing and characterization were performed before and after neutron irradiation. Miniature tensile specimens were irradiated at the High Flux Isotope Reactor (HFIR) to 0.2 and 2 displacements per atom (dpa) at 300 and 600°C. The AM 316L SS was tested in the as-built, stress-relieved, and solution-annealed conditions, and the wrought (WT) 316L SS in solution-annealed condition as a reference alloy. The baseline test result showed that the AM 316L SS, regardless of the post-build heat treatment, had higher strength than the WT 316L SS, but similar ductility. Post-irradiation tensile testing was conducted at RT, 300°C, and 500°C for selected irradiation conditions. Neutron irradiation induced significant changes in the mechanical behavior of the AM stainless steels, including both hardening and softening. Although the as-built 316L steel after 300°C irradiation showed necking just after yielding, the overall property changes of the as-printed alloy became less significant after 600°C irradiation. Irradiation-induced ductilization was also observed after the higher temperature irradiation. In general, the strength change was smaller in the relatively stronger as-built and stress-relieved AM SSs than in the solution-annealed AM and WT SSs. These relatively lower strength 316L SSs overall retained higher ductility in the irradiation conditions tested, but the stronger 316L SSs demonstrated a similar level of ductility after the higher temperature (600°C) irradiation. It is a positive assessment for the AM 316L materials that no embrittlement was observed within the test and irradiation conditions of the experiment.
Total body irradiation (TBI) remains an effective myeloablative treatment in regimens used for preparation and conditioning before allogeneic stem cell transplantation for leukemia. The regimens used ...vary across institutions in terms of dose, dose rate, fractionation, and technique. The objective of this document is to provide comprehensive guidelines for the current practice of delivering total body irradiation.
Irradiation induced growth is a constant volume shape change that occurs without externally applied stress that is observed in some materials under irradiation damage. Proton irradiation was carried ...out on a pure Zr sample to many dpa, to enable investigation of microscale aspects of the irradiation growth phenomenon. Irradiation induced a significant surface morphology change in the irradiated area, which is believed to be the result of the anisotropic growth behavior of the hcp structured Zr. The localized strain that developed was characterized by Electron back scatter diffraction (EBSD), on both the irradiated surface and on a cross sectional through-thickness plane. It was found that there is a correlation between the amount of local deformation and level of misorientation existing between two adjacent grains. The irradiation induced defect microstructure was characterized by transmission electron microscopy (TEM), showing 〈a〉 and 〈c〉 component loops similar to that generated by neutron irradiation in literature. Lastly, site specific focused ion beam (FIB) TEM lift-outs were prepared on local grain boundaries to investigate the origin of the localised deformation.
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