Typescript (photocopy). / Digitized by Kansas Correctional Industries / Department: Family Economics.

No description available.

A thesis submitted in fulfilment of the requirements for the degree of Doctor of Philosophy in the School of Chemistry Faculty of Science, University of Witwatersrand, 2017 / Advancements in nanotechnology and nanosystems promise to extend limits of sustainable development and environment remediation in an attempt to address some of the world most challenging problems. Specifically, nanotechnology has played an important role in the design, synthesis, and characterization of various new and novel functional nanomaterials possessing extremely unique properties. For example, low dimensional nanostructures such as semiconductor nanocrystals with well controlled sizes, shapes, porosities, crystalline phases, and structures have been prepared via various synthetic methods. In addition these semiconductor nanocrystals have attracted research attention because of their fundamental role in the comprehension of the quantum size effect and great potential applications to save resources and improve the environment. Tremendous studies have established that morphological, optical, catalytic and electronic properties of semiconductor nanocrystals can be manipulated during synthesis by simply varying the growth parameters. Herein we establish the effect of different synthetic methods and several growth parameters on the properties of the as-synthesized semiconducting metal selenides nanocrystals (NixSey and InxSey) including structural, optical, electronic and catalytic properties. For example, reducing coordinating solvent oleylamine was seen to favour a particular morphologies and stoichiometries despite the duration of synthesis. In the case of InxSey nanocrystals, oleylamine favoured indium monoselenide (InSe) nanosheet formation while addition of 1-DDT as a co-surfactant to oleylamine produces In2Se3 nanowires. For NixSey nanocrystals, TOP as a co-surfactant to different ligands favoured the formation Ni3Se2 with different shapes including dots, plates, rods and wires in different solvents. Other parameters studied included the reaction time and temperature. Besides the properties, we probe the potential applications of these materials in dye sensitized solar cells as counter electrodes as well in chemical sensor as the sensing material. NixSey nanocrystals were employed as CE in DSSCs in an attempt to replace the noble expensive platinum conventionally used as CE in most DSSCs. It was established that different stoichiometry played a significant role in the catalytic reduction of I3-. Thus, different photovoltaic performance parameters were obtained with NiSe2 giving a higher PCE of 1.5 % followed Ni3Se4 then Ni3Se2. These values were however very low compared to the ones reported in literature, something that was attributed to low electron mobility, enhanced recombination and reduced catalytic performance as a result of poor device assembly and the organic ligand layer encapsulating the nanocrystal. In another scenerio, indium monoselenide nanocrystals were employed in chemiresistive sensors to detect the presence of a number of VOCs including formaldehyde, methanol, chloroform and acetone in the ambient. Indeed despite the well-known electrical, optical and structural properties previously reported in literature, metal selenides such as CdSe, PbSe and ZnSe among others present lack of investigation for gas sensing. The experimental results showed that different morphologies of InSe nanostructures interacted differently to the analyte gas suggesting difference in the electronic properties of different morphologies. The InSe nanoparticle based sensors gave a good response to HCHO and MeOH fumes and were more selective to HCHO fumes than chloroform and acetone. While those fabricated using the InSe nanosheets though responding well to HCHO recovered half way when exposed back in air and resulted in relatively high noise to signal ratio when exposed to MeOH. The operating temperature range for the InSe sensor devices were determined to be near room temperature. The sensors response was observed to decrease with increasing temperature from 30 °C to 90 °C. Evident from the results, the surface capping molecule (oleylamine) employed to stabilize the nanostructures during synthesis was responsible for the poor sensing abilities of the nanostructures. / XL2018

The mandible is able to move in a complex fashion, with variable combinations of both translation and rotation in three dimensions (six degrees of freedom), at any given time during function. Research into the process of accurately capturing three-dimensional functional movement of the mandible has many broad clinical applications in dentistry and medicine alike. Anatomical kinematics of the craniofacial skeleton that includes motion analysis has potential scope for clinicians in the areas of diagnostics, treatment planning and treatment outcome assessment. The aims of this study were to describe mandibular motion during opening-closing tasks of two adult subjects and one growing subject with a Class II malocclusion, undergoing growth modification with a Clark Twin Block appliance. Motion analysis recordings were taken with the use of a twelve-camera motion analysis system (Motion Analysis Corporation). The values of the kinematic variables (translation [millimeters] and rotation [degrees]) of mandibular opening-closing that were obtained were consistent and repeatable for both adult subjects throughout this study. In contrast, those values obtained from the subject who wore a functional appliance show noticeable changes in the motion patterning during the initial stages (recordings taken at four and at eight weeks) of appliance wear. These are most apparent in the translation data recorded along the anterior-posterior axis. Mandibular motion however, seemed to return to near pre-treatment patterning in this individual following one year following the initiation of the appliance wear. These observations were seen in one experimental individual. Further research is needed to elucidate whether such changes in motion patterning are seen normally in the growing individual, or, are accountable due to the clinical intervention with an orthodontic appliance. This study piloted the use of two different splint designs for the purposes of recording mandibular motion in the two adult subjects. There were no significant differences in the recording of mandibular motion between the two different splint designs. One design has been recommended for future studies due to its overall ease of fabrication and intra-oral comfort for the subjects.

Thesis (Ph.D.)--University of Delaware, 2006. / Principal faculty advisor: Mary E. Galvin, Dept. of Materials Science & Engineering. Includes bibliographical references.

Thesis (M.S.)--University of Florida, 2000. / Printout. Vita. Includes bibliographical references (leaves 71-75). Also available on the World Wide Web; PDF reader required.

No description available.

Thesis (Ph. D.)--University of Florida, 2001. / Title from first page of PDF file. Document formatted into pages; contains vii, 145 p.; also contains graphics. Vita. Includes bibliographical references (p. 137-144).

Thesis (Ph. D.)--Rutgers University, 2009. / "Graduate Program in Mechanical and Aerospace Engineering." Includes bibliographical references (p. 155-159).

Thesis (Ph. D.)--University of Michigan, 1937. / Lithoprinted. Errata slip attached to front fly-leaf. Bibliography: leaves 106-107.