3. Electronic Theses and Dissertations (ETDs) - All submissions
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Item Sexual selection and signalling in the lizard Platysaurus minor(2008-04-08T09:37:37Z) Lewis, Belinda AnnABSTRACT Sexual selection may influence aspects of male morphology associated with territoriality, female choice, aggression and contest success. Attributes that are most commonly selected for include body size, condition, weaponry, endurance and bright coloration. I investigated the relationships between morphology, use of space and home range quality, and access to females. Specifically, I examined the relationships between colour, body size and condition, and whether morphology could predict aggression or contest success. Colour spectral data were analyzed using both traditional measures of colour (hue, chroma, brightness) and principal components. Males with darker, more saturated chests, and more saturated throats, had larger home ranges. Home range quality, as determined by refuge number and prey availability, was associated with blue chests and blue throats and chests, respectively. Males with larger home ranges had higher numbers of associated females and spent more time courting females. Larger males in better condition had darker, more saturated chests. Males in better body condition were also more aggressive. There was a consistent trend for larger males to win more contests, but this relationship was only significant in analyses using traditional measures of colour.Item Synchronous generator fault diagnosis using shaft signal measurements(2007-02-26T11:40:10Z) Hoffe, Simon JohnShaft voltages and currents are an unavoidable characteristic of rotating machines, though they are typically a nuisance this work shows that shaft signals can be used for fault diagnosis. This work focussed on shaft voltages present on synchronous generators. Measurements on a 4-pole generator found that the angular position of the shaft could be determined from the shaft voltage. An experimental 20 kVA 2-pole synchronous generator was designed and built which resembled a full-size 600 MVA turbo-generator. The effects of a static eccentricity on the shaft voltage were successfully determined firstly through FEM simulation and then verified with physical measurements. Shaft voltages can be used to diagnose static eccentricity, future work should investigate other faults. In addition, computer simulation was found to be effective and simulation and measurements of operating machines (such as turbo-generators) should be considered.