Preface

This book shows us a special chapter concerning the effect of all radiation types in materials. The study of radiation effects has developed as a major field of materials science from the beginning, approximately 70 years ago. Its rapid development has been driven by two strong influences. The properties of the crystal defects and the materials containing them may then be studied. The types of radiation that can alter structural materials consist of neu‐ trons, ions, electrons, gamma rays or other electromagnetic waves with different wave‐ lengths. All of these forms of radiation have the capability to displace atoms/molecules from their lattice sites, which is the fundamental process that drives the changes in all materials. The effect of irradiation on materials is fixed in the initial event in which an energetic projec‐ tile strikes a target. The book is distributed in four sections: Ionic Materials; Biomaterials; Polymeric Materials and Metallic Materials.

The first section presents four specific chapters: the first chapter investigates optical loss property specifically of silica fibers, theoretically and experimentally, based on their Ray‐ leigh scattering and absorption losses, which is very important and could help experts of this area. The second chapter presents the radiation effects on optical fibers and optical fi‐ ber–based devices as new materials, technologies and possible applications in radiation en‐ vironments emerged. The third chapter presents the studies on radiation damage caused by neutrons, primarily related to the displacement of atoms from their positions in the lattice of silicon semiconductor. The fourth chapter shows the evaluation of the changes in dielectric parameters (breakdown voltage, dielectric strength, dielectric constant, dissipation factor) of virgin and gamma-irradiated SiR-EPDM blends (five different compositions).

The second section presents five chapters relating to biomaterials: the first chapter of this section refers to radiological event; there would be a major need to establish, within a few days, the radiation doses received by tens or hundreds of thousands of individuals. This chapter will be helpful in this area (radiation and environmental biophysics). A comparison of the biological effect of neutron and X-ray exposure on micronuclei yields in peripheral lymphocytes demonstrated that the IND-spectrum irradiator described above gives RBE values within the expected range; the second chapter of this section shows the importance in controlling the radioactivity and principally the environment. All forms of radiation have the capability to displace atoms from their lattice sites or human cells or plants in general; this third chapter involves radiation influence on edible materials. A polymeric material that can be easily consumed by human beings or lower animals in whole or part, via the oral cavity, and given harmless effect to the health, is fundamental to show a state of the art about the effects of ionizing radiation on edible polymers, that is, starch and vegetal pro‐ teins, and also on gelatin that come from animal origin. The fourth chapter concerns the ex‐ perimental and theoretical results of LEE impact on single and double stranded DNA, its

basic constituents, protein subunits, as well as radiosensitizers and chemotherapeutic agents alone or bound to DNA were reviewed. The fifth chapter refers to microbiological analyses on municipal sewage sludge treated in a pilot plant process utilizing an electron accelerator (3 MeV) that is very important due to the way to show the potential of this technology to decontaminate sludge with 15% solids and really open new opportunities for large urban agglomerations to save money on sewage sludge treatment.

The third section presents chapters covering polymeric materials: the first chapter shows the effects of some radiation types (electron beam; gamma beam; proton beam) on the chemical structure, crosslinking process, thermal and crystallinity characteristics, as well as mechani‐ cal properties of polyamide-6 are discussed depending on absorbed dose. The second chap‐ ter of this section investigates low-energy ion-induced processes in B: PMMA [Positron annihilation spectroscopy (2.15 keV), optical (UV-visible region and Raman spectroscopy), electrical measurements and nanoindentation test] is valuable and could help us understand other options for optoelectronic materials (polymers). The third chapter of this section in‐ volves the effect of plasma, laser, microwave, electron beam and ion beam on surface, and chemical, physical and mechanical properties of textile materials are fully discussed. The ad‐ vantages of this technology are well known such as improvement in shades, enhancing col‐ our fastness, color strength, low cost-effective and reduction of the concentration of the used chemicals. The fourth chapter discusses comprehensively the irradiation pretreatment of tropical biomass prior to the subsequent enzymatic saccharification and fermentation proc‐ esses which can be applied as an alternative pretreatment approach for biofuel production.

The fourth section comprises metallic materials studies: the first chapter of this section con‐ cerns the experimental and computer simulation of low- and medium-energy ions collisions on the surface of a solid, and of the accompanying effects, namely, scattering, sputtering and surface implantation is treasured. The second chapter concerns the contribution of various irradiation damage mechanisms (thermal and fast neutrons) to the evolution of microstruc‐ ture and mechanical properties in all four regimes for 5xxx and 6xxx series aluminum alloys to understand the expected changes in mechanical properties of HFR vessel material in rela‐ tion to microstructural aspects beyond the current surveillance data to support the HFR SURP program. The third chapter of this section shows a parallel between laser irradiation and relativistic electrons irradiation of solids (graphite and tungsten). Simulations and ex‐ perimental data are presented; the fourth chapter involves the nanostructuring of metal sur‐ faces by laser ablation that is a very good technique which allows numerous technological developments ranging from Laser-Induced Breakdown Spectroscopy (LIBS), Pulsed Laser Deposition (PLD), laser propulsion, to surface modification and generation of nanoparticles, NPs. These effects or phenomena were found to occur during the implementation of the mi‐ cromachining processes and have gained relevance and are a very important source for the modification of surfaces for technological uses.

#### **Prof. Dr. Waldemar Alfredo Monteiro**

Materials Science and Technology Center Nuclear and Energy Research Institute São Paulo, SP, Brazil.
