Ion irradiation has been known to be an effective tool for structure modification with micro/nano-scale precision. Recently, demonstrations have been made for nano-machining, such as the cutting and welding of carbon nanotubes. Understanding the fundamental effects of ion irradiation on carbon nanotubes is critical for advancing this technique as well as for scientific curiosity. Molecular dynamics modeling was performed to study irradiation stability, structural changes, and corresponding thermal properties. In our study, Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) was used to perform atomic scale simulation. In order to understand size and geometry effects on carbon damage creation, the threshold energy of displacement was calculated as a function of recoiling angles for both single-walled and multi-walled nanotubes. A strong directional dependence was found to exist in different shells of multi-walled carbon nanotubes. We found that carbon atoms on the innermost tube were more susceptible to be displaced toward the center of axis. The calculation matrix was further extended to nanotubes having different diameters for a full-scale understanding of the creation of defects. Besides studies on defects creation, thermal properties of carbon nanotubes were studied via a simplified model of the carbon nanotube network. Thermal conductivity, were found to be increased nearly one order of magnitude in carbon nanotube networks after irradiation and subsequent annealing. All the modeling results were compared with experimental observations either obtained from this project as a parallel study or from previous works, for the purpose of verification and validation. For experimental works, atomic scale characterization was performed by using transmission electron microscopy and the thermal conductivity measurement was characterized by using laser flash technique. Through a combination of modeling and experimentation, we proved that ion beam techniques can be used to enhance thermal conductivity in carbon nanotube bundles by inter-tube defects mediated phonon transport.

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Historically, children with disabilities have been perceived as sources of stress, and disability has been portrayed in Western society as a tragedy to be avoided. This study used Appreciative Inquiry methodology and an integrated conceptual framework combining the Dynamic Ecological Systems Model, Cognitive Adaptation Theory, and components of the Affirmative Model of Disability. Qualitative interviews were conducted with ten children and sixteen parents to gain insight into their perceptions of the positive effects that a child with a disability has on the family. Findings suggest that children with disabilities can have some of the same positive effects on, and make some of the same contributions to, their families as any other child. They can also have unique positive effects and make unique contributions potentially unparalleled by their non-disabled peers. These findings may have implications for how disability is perceived by medical professionals, parents raising children with disabilities, and the public.

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In order to rationally optimize a reaction, it is necessary to have a thorough understanding of its mechanism. Consequently, great effort has been made to elucidate a variety of reaction mechanisms. However, the fundamental ideas needed to understand reaction mechanisms are not yet fully developed. Throughout the literature, one encounters numerous examples of experimental observations that are not explainable by conventional mechanistic ideas and methods. The research described in this dissertation employs a unique approach towards the identification and analysis of systems whose observations cannot be explained by conventional transition state theory (TST). The nucleophilic substitution of 4,4-dichloro-but-3-en-2-one by sodium-para-tolyl-thiolate was explored. It was deduced that the reaction was concerted and consequently, the product selectivity observed in the reaction cannot be explained by TST. Dynamic effects play a major role in the observed selectivity and this is further supported by the results of dynamic trajectory simulations. Using computational studies, the ethanolysis of symmetric aryl carbonates was also shown to be concerted, provided that the substrate possesses good leaving groups. Furthermore, extensive precedence has been set by Gutthrie, Santos, Schelgel, and others, detailing concerted substitutions at acyl carbon. The Fujiwara hydroarylation is thought to occur by either a C-H activation mechanism or an electrophilic aromatic substitution (EAS). The KIEs associated with this reaction have been determined and provide strong support for the latter. Computational studies also displayed fair agreement with experimentally determined KIEs, further supporting the EAS mechanism. Isotopic perturbation of equilibria is invaluable in helping to determine whether a structure exists as a single structure or whether it is a time average of two equilibrating structures. The bromonium cation of tetramethylethylene and hydrogen pthalate have been wrongly reported as existing as equilibrating structures. The time averaged geometries have been determined in each case, via a variety of methods and the myth of equilibrating structures in the above cases has been debunked.