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Ph.D. (Botany) / Please refer to full text to view abstract

The facial pits characterizing the snake subfamily Crotalinae have been demonstrated to be important as thermoreceptors in detecting the presence of prey animals and in directing the stroke towards them. So specialized a receptor as the pit organ, if it is to survive, must be functionally effective. If this organ is important in locating prey under natural conditions it would be expected that if these pits were destroyed this importance would be reflected in growth rates, weight changes,, or survival. In twenty of forty snakes collected in the spring of 1963 the pits were destroyed by electric cautery. After weighing, measuring, and marking, the snakes were released at the point of capture. The growth of the recaptured cauterized and non-cauterized snakes was compared. In addition, controlled tests were made with the recaptured snakes, using live mice and light-proof boxes to determine the effectiveness of cautery. A significant statistical difference was found in the growth rates of the females, the cauterized snakes growing more slowly. No difference was found in the growth rates of the males. However, the controlled tests indicates the pits to be important to the males as well as to the females. Weight changes were too variable to reveal differences between normal and cauterized snakes and no difference in survival was evident between the two treatments. To overcome the effect of individual variation in growth rate further study is required of larger samples over a longer time period. / Science, Faculty of / Zoology, Department of / Graduate

Bitumen exploitation in Alberta’s oil sand region generates considerable amounts of waste including tailings and process-affected water that needs reclamation. Water capped tailings technology (WCTT) is currently being assessed as a potential wet reclamation strategy in the oil sand by the commission of Base Mine Lake (BML), the first commercial scale Pit Lake. Pit Lakes consist of ~40m of fluid fine tailings (FFT) deposited in old mine pit covered with a ~10m water cap. In order to be successful, pit lakes much achieve the ecological roles of a natural lake, which includes colonization of the water by macrofauna therefore necessitating the water cap to be oxic. Due to the reductive nature of the tailings, oxygen consuming constituents (OCC) such as methane, sulfide and ammonia are released from the FFT into the water cap potentially posing a threat to the success of the reclamation. Additional seasonal effects such as stratification and ice cover may further affect oxygen consumption by isolating parts of the water cap therefore allowing accumulation of OCC. Results shows that BML thermally stratifies during the summer and winter and that oxygen persist throughout the water cap despite reaching low level at the FFT-water interface (FWI) during summer. Consistent with the FFT acting as an OCC source, aqueous CH 4 and NH 4+ concentrations were highest closer to the FWI, decreasing upwards into the water cap. Using linear regression CH 4 was shown to be an important OCC during the summer of 2015 while NH 4+ and CH 4 were both important for the summer of 2016 highlighting the emergence of nitrification in BML. Detailed analysis of seasonal data revealed that accumulation of OCC below the hypolimnion depletes oxygen and favors methanotrophic activity. Results from both studies suggest that methanotrophs have a competitive advantage at low oxygen levels against nitrifiers. / Thesis / Master of Science (MSc) / Bitumen extraction in Alberta’s oil sand region generates substantial amounts of waste including tailings that needs reclamation. Pit Lakes have been proposed as a reclamation strategy, where tailings are deposited into a mined-out pit and covered with a water cap. To achieve the reclamation goal, the lake must be able to sustain life and must therefore maintain an oxic water cap. The underlying tailings poses a threat to the oxygenation of the lake because of the constant release of compounds that have the potential to consume oxygen. Additional seasonal effects due to temperature change may further affect oxygen consumption by isolating parts of the water cap. In this thesis the results of two years of field sampling and analyses show that despite active oxygen consumption from tailings-released compounds, oxic status is achieved in the upper layer of the lake during summer and under ice.

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Student Number : 0112584H - MSc research project - School of Mining Engineering - Faculty of Engineering and the Built Environment / With the acquisition by AngloGold Ashanti Ltd of open pit mines in East and West Africa with possible addition of Greenfield and Brownfield operations, the emphasis of this research document was to improve the current open pit mines in this region. By identifying Mineral Resource Management (MRM) as a way to improve and manage operating practices, additional value and the accompanied risks have been identified. It was also realised that the current traditional, predominantly financial indicators are becoming increasingly inadequate, thus looking at alternative operating principles. Subsequent to this, proposals have been made to acquire the necessary production and cost change by integrating structure, strategy, systems, style, skills, staff and the defined goals as proposed in this document. Using a “process-based” approach integrating (best) operating practices, concepts such as: living out the company’s strategic values; a learning organisation; better informed decision-making; people management; self-directed teams; continuous improvement; asset and capital management; integrated information systems; and an improved internal and external customer relationship be obtained.

Abstrate Co1-XO polycrystals, prepared by sintering at 1600oC with or without Mg2+-dopant ,were thermally etched at 400-1500oC for 10 min-12hr and studied by scanning electron microscopy regard to the effects of temperature and Mg2+-dopant on etching development. In low etching temperature (400-800 oC), vacancy relaxation process and spinel precipitate produced on the surface of Co1-XO-MgO polycrystals. In high etching temperature (1500 oC), Co1-XO epitaxy was spread on the steps and ledges. In addition, Co1-XO was thermally etched at 1500 oC for 10min to 12hr, we found triangular to hexagonal etch pits were produced. However, Mg2+-dopant changed the geometric shape of the pit opening. Besides, growth hillocks with corrugated terrace steps at edge and a pit at center showed that growth and etching of crystal can happen in the same time.