577 research outputs found
THE ECOLOGICAL CONSEQUENCES OF HABITAT AND MICROHABITAT USE IN LIZARDS:: A REVIEW
We review the ecological consequences of habitat and microhabitat use in lizards. Different habitats have different biotic and abiotic properties and thus are likely to have different consequences for the lizards that occur in them. Individual performance and life histories are influenced by habitat use, particularly when habitats differ in thermal characteristics that may influence physiological processes or constrain activity. We know relatively little about how the effects of habitat use on individual performance translate into population dynamics. We do know that the ability of lizards to use particular habitats can influence the persistence of populations in the face of habitat changes. Community-level processes (e.g., competition) and community structure (e.g., diversity) can be influenced by habitat use in lizards, often by habitat use facilitating co-existence of two or more potentially competing species. We know relatively little about how other community processes, such as predation and parasitism, are influenced by habitat use
Master of Science
thesisTar sand deposits in Utah represent more than 25 billion barrels of in-place bitumen, 96% of the known U.S. reserves. Although dwarfed by the size of the well known Canadian tar sand deposits, the Utah tar sands may provide a new domestic source of synthetic crude oi1. The hot water process for Utah tar sands differs significantly from the co~i111ercially practiced hot water process for Athabasca (Canadian) tar sands. The process strategy differences reflect the inherent differences in the respective bitumen physical and chemical characteristics and the nature of the bitumen-sand association. In a six year research program the criteria have been identified that are necessary to achieve satisfactory phase disengagement in digestion. The focus of this report is to present findings on the conditions which achieve the best phase separation of bitumen from sand in the flotation of Asphalt Ridge tar sand following digestion. Although contact angle measurements of feed material and pure bitumen indicated slight and moderate hydrophobicity respectively, air bubble attachment to a bitumen concentrate was not possible. This surprising result suggests that the flotation separation is dependent on air bubble entrapment rather than on attachment due to s~rface hydrophobicity. The occlusion of air bubbles in the bitumen was apparent from the visual examination of the nature and behavior of the concentrate. A factorial design of the major operating variables in the flotation separation indicates that the quality of phase separation is significantly dependent on flotation temperature and to a lesser extent on the degree of agitation. Under the best flotation condition recoveries of 96% and concentrate grades of 60% bitumen were realized. The improved separation at higher flotation temperatures is due to the decreased bitumen viscosity resulting in more effective rejection of coarse sand from the bitumen. The addition of a small amount of sodium carbonate in flotation is needed to prevent the concentrate from being excessively sticky. The small addition also slightly improves the quality of separation. At sodium carbonate additions greater than 0.075M the system develops a voluminous unmanageable froth. Diluent additions to flotation did not increase the quality of separation or appear to alter the hydrophobicity of the bitumen surface. Study of the percent solids in flotation was not conclusive but indicated that reasonable separations can be obtained at up to 40 percent solids. Preliminary settling tests resulted in the development of a flocculant addition schedule which gives rapid settling and a clear supernatant. Water recycling tests using water from which the suspended solids were removed by polymeric flocculants did not show any detrimental effects due to residual polymers and/or soluble organics. Results from liquid-solid separation tests and water recycling are preliminary in nature. v 'I Finally, based on the experience and results compiled over the life of this research program a flowsheet is proposed for the pilot plant production of 2,000 barrels per day of synthetic crude oil. The preliminary costs estimate indicates a total capita 1 expenditure of $5,228,500 .:!:_ 30 percent would be required for the hot water processing portion of such a plant
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Building Blocks of Effective Leadership
Three individuals will share their perspectives about mentoring and guidance within academia. They will discuss how the networking, questioning and formation of feedback opportunities in their relationships have contributed to their evolution as administrators—from department chair to provost
Cultivating a Community of STEM Polymaths at UNG
The University of North Georgia (UNG), Dahlonega, suffers from high attrition of STEM majors and low STEM graduation rates. In response to this challenge, a transdisciplinary (TD) team of UNG STEM faculty – from biology, chemistry, mathematics, and physics - has designed and developed hands-on laboratory experiments that employ empirical, interpretive, critical, and transdisciplinary research methodologies. The TD laboratory curriculum exposes undergraduate STEM students to cutting-edge techniques and new scientific frontiers, which will foster creativity and passion about scientific research, help undergraduates develop skills in analytical thinking and experimental design, and improve their technological fluency. In turn, this will improve persistence by stimulating student interest and participation in STEM. We will present examples of the transdisciplinary experiments that our students are engaging in and provide interactive activities to expose an interdisciplinary audience to the substantive scientific questions and real-world observations of the TD lab at UNG
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