Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1992. / Vita. Abstract. Includes bibliographical references (leaves 128-135). Also available via the Internet.

Thesis (Ph. D.)--West Virginia University, 2009. / Title from document title page. Document formatted into pages; contains xi, 240 p. : ill. (some col.), maps (some col.). Vita. Includes abstract. Includes bibliographical references.

Title page, abstract and table of contents only. The complete thesis in print form is available from the University of Adelaide Library. / Tasmanian fossil sites are rich in Cupressaceae genera and species and yet only three genera (Artrotaxis, Diselma, Callitris) survive there today. The aim of this study is the identification of some new and previously undescribed Cupressacea-related Tasmanian fossils. This is achieved by comprehensive morphological reviews of the foliage and cones (ovulate and pollen) of six extant Southern Hemisphere Cupressaceae genera. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1277497 / Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2007

Title page, abstract and table of contents only. The complete thesis in print form is available from the University of Adelaide Library. / Tasmanian fossil sites are rich in Cupressaceae genera and species and yet only three genera (Artrotaxis, Diselma, Callitris) survive there today. The aim of this study is the identification of some new and previously undescribed Cupressacea-related Tasmanian fossils. This is achieved by comprehensive morphological reviews of the foliage and cones (ovulate and pollen) of six extant Southern Hemisphere Cupressaceae genera. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1277497 / Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2007

Thesis (M.S.)--University of Wyoming, 2008. / Title from PDF title page (viewed on Mar. 26, 2010). Raw data available as a supplemental file in Microsoft Excel. Includes bibliographical references (p. 31-37).

Thesis (M. Sc.), Memorial University of Newfoundland, 1999. / Bibliography: p. 271-290.

Fossil plants in the Upper Triassic Chinle Formation are preserved in fluvial channel, overbank, and lacustrine deposits. Plant-bearing units in these deposits are classified into seven types based on these depositional environments or subenvironments. Taphonomic characteristics of these assemblages, and of individual plant fossils within them, indicate that most plant fossils have either not been transported far from their growth sites or are preserved in situ. One particular deposit in the central part of Petrified Forest National Park preserves fossil plants in three associations: (1) allochthonous logs in basal lags in a channel-fill/lateral accretion deposits; (2) autochthonous horsetail trunks and parautochthonous horsetail leaves in a crevasse-splay deposits; and (3) parautochthonous and autochthonous cycadaceous, fern and other types of leaves, and erect and prostrate trunks in a paludal/distal splay deposits. Exposures of contemporaneous high-sinuosity channel and overbank deposits in this area enabled the reconstruction of the local paleogeography, paleohydrology, and paleoecology at a high resolution. Fossil plant assemblages of the Upper Triassic Chinle Formation are concentrated in the lower members of the formation. The lower part of the Chinle Formation was deposited in an incised valley system. Depositional, hydrological, and near-surface geochemical conditions in the incised valley system were conducive to preservation of terrestrial organic material, even though regional conditions were characterized by seasonal/monsoonal precipitation and groundwater conditions. Fossil plant assemblages preserved in these types of fully terrestrial incised valley-fills are taphonomically biased towards riparian wetland environments.

A newly discovered fern-like fossil plant is described from the Lower Upper Devonian of southern Ellesmere. This plant occurs as an element of an Archaeopteris dominated flora preserved in sediments of the Nordstrand Point Formation (mid-late Frasnian) at Bird Fiord. The plant demonstrates a pinnate vegetative system with three orders of branch and laminate pinnules, of a general sphenopteroid type. Primary pinnae usually diverge from the main axis in distichous pairs (Le., in a quadriseriate manner), but rarely depart singly (i.e., in a biseriate manner). Each primary pinna bears an aphlebia in the catadromic position. Laminate pinnules are broadly lobed with a proximally overtopped vein system. Anatomically, this plant is characterized by an elongate, mesarch, bipolar protostele that is ribbon to clepsydroid in shape. Proximal to each primary pinna node, an initially crescent-shaped, bipolar pinna trace diverges from the main axis stele. This trace appears to become four-ribbed before dividing to yield a pair of bipolar primary pinna traces. A pair of circular, centrarch aphlebia traces depart from the catadromic ribs of a primary pinna trace in its four-ribbed stage. Protoxylem is helically thickened, with metaxylem pitting ranging from scalariform to circular. Secondary xylem is unknown. Both the morphology and anatomy of this plant are non-gymnospermous and suggest affinity instead with zygopterid ferns. Within the Zygopteridales, this plant seems to align most closely with the Rhacopytaceae. The Frasnian dating of this plant suggests that laminated foliage had been achieved by some zygopterid ferns long before previously recognized. The presence of Sphenopteris-like pinnules in this Frasnian plant also shows that one should be careful in attributing such foliage to early gymnosperms. / Master of Science

Maintenance of power plants is aimed at extending the life and reducing the risk of sudden breakdown of power generating units. Traditionally, power generating units have been scheduled for maintenance in periods to ensure that the demand of the system is fully met and the reliability of the system is maximized. However, in a deregulated power industry, the pressure of maintaining generating units is also driven by the potential revenue received by participating in the electricity market. Ideally, hydropower generating units are required to operate during periods when electricity prices are high and to be able to be taken offline for maintenance when the price is low. Therefore, determination of the optimum time periods for maintenance of generating units in a power system has become an important task from both a system reliability and an economic point of view. Due to the extremely large number of potential maintenance schedules, a systematic approach is required to ensure that optimal or near-optimal maintenance schedules are obtained within an acceptable timeframe. Metaheustics are high-level algorithmic frameworks that aim to solve combinatorial optimisation problems with a large search space in a reasonable computational run time. Inspired by the foraging behavior of ant colonies, Ant Colony Optimisation (ACO) is a relatively new metaheuristic for combinatorial optimisation. The application of ACO to a number of different applications has provided encouraging results when applied to scheduling, including the job-shop, flow-shop, machine tardiness and resource-constrained project scheduling problems. In this thesis, a formulation is developed that enables ACO to be applied to the generalized power plant maintenance scheduling optimisation (PPMSO) problem. The formulation caters for all constraints generally encountered as part of real-world PPMSO problems, including system demands and reliability levels, precedence rules between maintenance tasks, public holidays and minimum outage durations in the case of shortening of maintenance tasks. As part of the formulation, a new heuristic and a new local search strategy have been developed. The new ACO-PPMSO formulation has been tested extensively on two benchmark PPMSO problems from the literature, including a 21-unit and a 22-unit problem. It was found that the ACOPPMSO formulation resulted in significant improvements in performance for both case studies compared with the results obtained in previous studies. In addition, the new heuristic formulation was found to be useful in finding maintenance schedules that result in more evenly spread reserve capacity and resource allocations. When tested using a modified version of the 21-unit and the 22-unit problems, the new local search strategy specifically designed for duration shortening was found to be effective in searching locally for maintenance schedules that require minimal shortening of outage duration. The ACO-PPMSO formulation was also successfully able to cater for all constraints as specified in both original and the modified versions of the two benchmark case studies. In order to further test the ACO-PPMSO formulation developed, it was first applied to a scaled-down version of the Hydro Tasmania hydropower system (five power stations) and then to the full system (55 generating units). As part of the studies, the ACO-PPMSO formulation was linked with the simulation model used by Hydro Tasmania to assess the impact of various maintenance schedules on the total energy in storage of the system at the end of the planning horizon, the total thermal generation, the total number of days where the reliability level is not met, as well as the total unserved energy throughout the planning horizon. A number of constraints were considered, including the anticipated system demands, a 30% capacity reliability level, the minimum and maximum durations between related maintenance tasks, the precedence constraints and the minimum outage duration of each task in the case of shortening of maintenance tasks. The maintenance schedule was optimised for the maximum end-of-horizon total energy in storage, the minimum thermal generation and the minimum total outage durations shortened and deferred, under 77 different inflow conditions. The optimal maintenance schedule obtained compared favourably with that obtained by Hydro Tasmania over many years based on experience. Specifically, the ACO-PPMSO schedule results in higher end-of-horizon total energy in storage and satisfies both hard and soft constraints, which overall equates to over $0.5 million dollars of savings when compared to the schedule obtained using the practitioners’ experience and engineering judgment. The ACO-PPMSO algorithm was also shown to be a useful decision-making tool for scheduling maintenance under different circumstances when tested with four scenarios commonly encountered in practical maintenance scheduling problems. In conclusion, the ACO-PPMSO formulation developed, tested and applied as part of this thesis research provides a powerful and flexible means of obtaining optimal or near-optimal maintenance schedules for power plants. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1294672 / Thesis (Ph.D.) -- University of Adelaide, School of Civil and Environmental Engineering, 2007

The Early Cretaceous (Berriasian) Hope Bay flora is one of the most diverse assemblages from the Mesozoic of Antarctica. Collected in 1902 by the Swedish Antarctic Expedition of 1901-1903 from Hope Bay at the northern tip of the Antarctic Peninsula, and described in 1913 by T. G. Halle, it has served as a classic reference collection for Jurassic and Cretaceous southern hemisphere paleobotanical studies. Because the systematics of the flora were outdated by the enormous advances in our understanding of fossil plants during the last 70 years, it was in serious need of revision. This revision has reduced the number of taxa from 61 to 42 species. Newly erected species are Otozamites rowleyi, Kachchhia schopfii, Ticoa jeffersonii, and Araucaria antarctica. New combinations are Todites grahamii and Thinnfeldia salicifolia. The genera Kachchhia, Ticoa, and Weltrichia are new occurrences at Hope Bay. Represented in the flora are members of the Hepatophyta, Arthrophyta, Pteridophyta, Pteridospermophyta, Cycadophyta, Cycadeoidophyta, and Coniferophyta. Not surprisingly, when compared with other Gondwana floras, the Hope Bay flora shows the greatest similarity with other Antarctic floras. There is also a close affinity with the floras of South America and New Zealand. Taxonomic similarity between these floras is best explained by paleogeographic proximity. / text