No description available.

Thesis (Ph. D.)--University of Tennessee, Knoxville, 2003. / Title from title page screen (viewed Nov. 11, 2003). Thesis advisor: Robert D. Hatcher. Document formatted into pages (xiii, 296 p. : col. ill., col. maps). Vita. Includes bibliographical references.

Thesis (Ph. D.)--University of Tennessee, Knoxville, 2003. / Vita. Includes bibliographical references.

Thesis (Ph.D.)--University of Alabama at Birmingham, 2008. / Title from PDF title page (viewed on July 15, 2010). Includes bibliographical references.

Two experiments investigated the effects of pre-receptoral absorption and levels of illumination on colour vision. Simulation filters approximating lens and macular pigment changes were constructed on the basis of previous investigations. Experiment I investigated the effects of these filters on young, normal subject performance. Shifts were found in the direction of ageing populations but not as great as is required. Experiment II investigated the additional effect of reductions in illumination. The two experimental manipulations together account for senile decreases in discrimination at slightly higher levels than previously reported / Arts, Faculty of / Psychology, Department of / Graduate

To make solar energy mainstream, lower-cost and more efficient power generation is key. A lot of effort in the silicon photovoltaic industry has gone into using fewer raw materials (i.e., silicon) and using more inexpensive processing techniques and materials to reduce cost. Utilizing thinner substrates not only reduces cost, but improves cell efficiency provided both front and back surfaces are well-passivated. In the current work, a kerf-less process is developed in which ultra-thin (~25 [mu]m), flexible mono-crystalline silicon substrates can be obtained through an exfoliation technique from a thicker parent wafer. These substrates, when exfoliated, have thick metal backing which provides mechanical support to the thin silicon and enables ease of processing of the substrates for device fabrication. Optical, electrical, and reliability characterization studies for completed cells show this technology’s compatibility with a heterojunction solar cell process flow. Building on the promising results achieved on exfoliated substrates, further optimization work was carried out. Namely, an improved cleaning process was developed to remove front surface contamination on textured surfaces of exfoliated, flexible mono-crystalline silicon. This process is very effective at cleaning metallic and organic residues, without introducing additional contamination or degrading the supporting back metal used for ultra-thin substrate handling. Spectroscopic studies were performed to qualitatively and quantitatively understand the efficacy of different cleaning procedures in order to develop the new cleaning process. Results of the spectroscopic studies were further supported by comparing the electrical performance of cells fabricated with different cleans. To replace silver as contact metal with a cheaper substitute like nickel or copper, patterning and etching processes are generally used. A low-cost alternative is proposed, where a reusable shadow mask with a metal grid pattern is kept in contact with the surface of the substrate in a plasma-enhanced chemical vapor deposition chamber during silicon nitride deposition. This leaves a patterned silicon surface for selective metal growth by direct electro-deposition. The viability of this process flow is demonstrated by fabricating diffused junction n[superscript+]pp[superscript+] monofacial and bifacial cells and electrically characterizing them. Investigation of the factors limiting the efficiency of the cells was carried out by lifetime measurement experiments. / text

A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of requirements for the degree of Master of Science. Johannesburg, 2015. / The ca. 36 Ma Chesapeake Bay impact event on the east coast of Virginia, USA, formed an 85 km complex crater in Cretaceous to Eocene sediments and underlying crystalline basement rocks belonging to the Appalachian orogen. Appalachian rocks are well exposed along the Appalachian Mountains to the west, however, little is known of the basement along the Atlantic Coastal Plain owing to the covering sedimentary sequence. This study investigates the crystalline rocks intersected by the 2006 ICDP (International Continental Scientific Drilling Program) – USGS (United States Geological Survey) drilling of the Chesapeake Bay impact structure (CBIS) on the Eyreville Farm near Cape Charles, Virginia. The crystalline rocks of the Eyreville-B borehole core are found in the lower basement-derived section (between 1551.19 m and 1766.32 m depth), in the amphibolite megablock (between 1376.38 m and 1389.35 m depth) and in the upper granite megablock (between 1095.74 m and 1371.11 m depth). The lower basement-derived section consists of foliated metasediments, which include mica schist, amphibolite and calc-silicate rock, and coarse-grained to pegmatitic granite. The amphibolite megablock is a black to dark grey to dark green, fine- to medium-grained, locally foliated, relatively homogenous, lithic block. The upper granite megablock is divided into gneissic and massive varieties, with a minor component of biotite schist xenoliths. The crystalline rocks contain foliations and related structures, fractures and breccias, microstructures and porphyroblast microstructures; however, none of the three lithic blocks is in situ and, consequently, structural measurements cannot be fully interpreted tectonically. Mineral assemblages and microstructural evidence in the mica schists suggest the rocks in the lower basement-derived section experienced a syn-D1 amphibolite facies peak metamorphic event (M1a) followed by retrograde metamorphic conditions (M1b) limited to D1b mylonitic and D2 brittle deformation. Similar metamorphic conditions in the upper megablocks suggest that the three sections likely formed part of a single metamorphic terrane. iv Geochemistry in the lower basement-derived mica schists revealed a strong intermediate igneous provenance, whereas the upper megablock biotite schist xenoliths showed a quartzose sedimentary provenance; the precursors to both appear to have been deposited in active continental margin settings. The lower basement-derived amphibolite appears to be derived from a sedimentary source. The precursor to the upper amphibolite megablock, on the other hand, was probably a tholeittic gabbro generated in an island arc setting. The peraluminous, S-type nature of the lower basement-derived granite suggests it was most likely generated in a within-plate tectonic setting. In contrast, the massive and gneissic granites from the upper megablock are metaluminous, I-type granites that were most likely generated in a syn-collisional environment. Metamorphic conditions of the M1 event were constrained using mineral assemblages mainly from the lower basement-derived section, which limited the X(H2O) value to 0.8, P to >0.4 GPa and the T range to 600-670°C. Using the 0.4 GPa pressure constraint, Zr-in-rutile thermometry revealed a peak metamorphic temperature for the M1 event of 606 ± 18°C, which is consistent with mid-amphibolite facies metamorphism. These estimates suggest a very steep geothermal gradient approaching ~44°C/km. Rutile U/Pb geochronology revealed that the M1 event recorded in the lower basement-derived metasediments occurred at 259 ± 13 Ma, with Ar/Ar geochronology indicating the cooling path through to greenschist metamorphic conditions. Zircon U/Pb SHRIMP geochronology performed by Horton et al. (2009b) on the massive and gneissic megablock granites dated their crystallisation ages at 254 ± 3 Ma and 615 ± 7 Ma, respectively, with the former age in agreement with the rutile U/Pb peak metamorphism results from the lower basement-derived section. These ages, together with petrography, structural observations, geochemistry and geothermobarometry suggests that the amphibolite and granite megablocks form part of the same metamorphic terrane as the lower basement-derived section and that the D1 and M1 events recorded in the lower basement-derived section and upper megablocks of the Eyreville-B borehole core likely occurred during the late stages of the Alleghanian orogeny. v Based on mineralogy, geochemistry, metamorphic grade and structural evidence, comparisons with the neighbouring terranes within the Appalachian basement beneath the Atlantic Coastal Plain sediments suggest that the lower basement-derived and upper amphibolite and granite megablocks of the Eyreville-B borehole core most likely formed part of the Hatteras terrane prior to the Chesapeake Bay impact event. This terrane, together with 5 other terranes, forms part of the Carolina Zone, a peri-Gondwanan micro-continent formed by the amalgamation of magmatic arcs during the Penobscottian and Taconian orogenies, which was then accreted onto the Laurentian margin during the Salinic and Acadian orogenies.

Thesis (M.Eng.)--Memorial University of Newfoundland, 2005. / Bibliography: leaves 87-90.

Thesis (Ph.D.)--University of Delaware, 2006. / Principal faculty advisor: Melinda K. Duncan, Dept. of Biological Sciences. Includes bibliographical references.

Thesis (Ph. D.)--West Virginia University, 2004. / Title from document title page. Document formatted into pages; contains x, 201 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 185-201).