Thesis (M.S.) in Chemical Engineering--University of Maine, 2002. / Includes vita. Includes bibliographical references (leaves 69-72).

Thesis (Ph. D.)--Lehigh University, 2003. / Includes vita. Includes bibliographical references (leaves 100-104).

Metal oxides are important materials that are being developed for use in research and health-related applications. In particular, TiO2 and ZnO nanomaterials for applications in antibacterial coatings, pollutant purification, and photovoltaic devices have been extensively studied. The photocatalytic performances are highly dependent on morphology and crystal structure. However, there are few studies are comparing pollutant purification and antibacterial behavior of different TiO2 nanostructures and less studies of antibacterial activity related to fundamental properties of ZnO. In this study, the details of proposed mechanism and principle of antibacterial mechanisms of metal oxide nanostructures has been examined. Different TiO2 nanostructures (nanotubes, nanorods) have been successfully synthesized and their photocatalytic properties have been studied. In addition, studies of basic properties of commercial ZnO nanoparticles related to antibacterial activity have been performed. / published_or_final_version / Physics / Master / Master of Philosophy

Not available / text

published_or_final_version / abstract / toc / Chemistry / Doctoral / Doctor of Philosophy

No description available.

No description available.

Various aspects of the tunneling states problem in metallic glasses are examined. As a first step, a computer model based on the analogy between local environments in crystalline and amorphous states is developed and used to generate and relax structures for two specific materials, namely Ni(,80)P(,20) and Cu(,33)Zr(,67). The model is found to give a physically realistic picture of the systems examined, in particular by properly accounting for short-range order effects. The structures are then analyzed in terms of single-atom tunneling taking place between two metastable minimum-energy positions. The probability of occurence of such "two-level systems" (TLS's) is shown to be strongly correlated with the degree of relaxation and thus with the density of the system. Further, they are seen to be associated with voids in the structure which disappear upon relaxation, suggesting an analogy with the physical process of annealing metallic glasses below their glass transition temperatures. It is therefore concluded that a reduction of the various low-temperature anomalies in these materials should result from the annealing process. As a verification, the change in superconducting transition temperature T(,c) due to the presence of TLS's is evaluated. In leading to a non-negligible enhancement effect, our model is indeed found to provide a reasonable estimate of the observed drop in T(,c), thus corroborating our hypothesis of a reduction of the TLS density of states upon thermal relaxation.

No description available.

No description available.