Motion of organs and tissues causes X-ray localization error during radiation therapy. Therefore, physical phantoms utilizing materials with tissue-equivalent mechanical and radiological properties are desired to simulate organ motion for radiotherapy optimization. However, it is still a challenge to develop such materials. Alginate hydrogels have similar properties to extra cellular matrix, which make them promising for use as tissue-equivalent materials. In this study, alginate hydrogels and hydrogel foams with desired mechanical and radiological properties were synthesized through in-situ release of Ca2+. The concentration, Ca2+:-COOH molar ratio, and air volume ratio were controlled to obtain hydrogels and hydrogel foams tailored to specific mechanical and radiological properties. Both macroscopic and microscopic morphologies of the materials were characterized. The change in molecular bonding in the hydrogels was characterized through FTIR. Tensional and compressive behaviors of the hydrogel material were investigated. Radiological properties were estimated theoretically and validated through CT scanning experiments. Ultimately, the synthesis-structure-property relationship was established to guide future developments. This study has elucidated the development of future tissue-equivalent materials which could be applied for optimization of radiation dosage and quality control during radiotherapy. The second component of this dissertation is the development of a novel metal matrix composite consisting of nanosilver/silver nanoparticles through an electroplating process. The composite offers excellent mechanical properties, high electrical conductivities, and scalability to meet desired industrial needs such as conductive coating in extreme environments. Specifically, metal matrix composites were prepared to obtain nanosilver/silver nanoparticle composites on a copper substrate. Nanosilver particles were introduced through an electroplating process to enhance the mechanical and conductive properties. The electroplating current and time were controlled to obtain composites with desired mechanical and conductive properties. The morphologies, mechanical properties, and electrical conductivity were determined. The influence of electroplating process parameters on the mechanical and conductive behaviors was investigated. This study has contributed to understanding the electroplating process-structure-property relation of metal matrix composites with improved mechanical properties and electrical conductivity.
| Identifer | oai:union.ndltd.org:ucf.edu/oai:stars.library.ucf.edu:etd2020-2916 |
| Date | 01 January 2023 |
| Creators | Li, Xiangpeng |
| Publisher | STARS |
| Source Sets | University of Central Florida |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Electronic Theses and Dissertations, 2020- |
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