A series of model steels containing copper levels up to 0.48wt%, nickel up to 0.22wt% and silicon levels of 0.52wt% were oxidised in air at 1050 and 1150??C, and in a CO2-N2 mixture at 1250??C for times of up to 3 hours. The scaling kinetics were measured and the behaviour of copper-rich phase formation at the scale/metal interface was investigated. When oxidised at 1050/1150??C, significant quantities of copper-rich phase were observed for most model steels. The relatively high oxidation rate under these conditions led to the rapid development of a copper-rich layer with little copper diffusing into the metal. However, when oxidised at 1250??C, the copper-rich phase did not form for a significant amount of time; and for some model steels, not at all. This was attributed to the considerably lower oxidation rate and the fact that more copper was found to have diffused into the metal. Alloying additions of nickel and silicon were found to be beneficial in reducing the amount of copper-rich phase measured at the scale/metal interface under the conditions investigated at 1150??C and 1250??C. This occurred because nickel and silicon addition promoted the occlusion of copper-rich phase into the scale. Copper enrichment during oxidation was modelled using a numerical description of the diffusion processes involved. Predictions of the time for commencement of copper-rich phase formation at 1250??C were in close agreement with observation. Agreement between predicted and observed copper-rich layer thickness was less successful under conditions where occlusion was significant, and the measured thickness varied non-uniformly with time. The cracking susceptibility of the model steels was examined using a hot compression test. Oxidation was performed in air at 1050, 1150 and 1250??C and most specimens were compressed at 1050??C. The amount of cracking was found to increase with the amount of copper-rich phase precipitated at the scale/metal interface during oxidation. In general, nickel addition reduced the amount of cracking at all temperatures; and under some conditions prevented cracking altogether. Silicon reduced or completely suppressed cracking when the subscale formed was liquid. The beneficial effects of nickel and silicon addition were attributed to their effect of promoting copper occlusion.

This thesis examined whether it is possible to enhance core elements of the information processing system with specific forms of environmental stimulation. The first series of experiments demonstrated that a preweaning environmental enrichment procedure that provided 60 minutes of daily multisensory stimulation accelerated the development of long-term contextual memory and enhanced inhibitory processing in young rats. That is, whilst stimulated and non-stimulated rats exhibited long-term memory of a context at 26 days of age, only stimulated rats showed this ability at 18 days of age. In addition, stimulated rats showed a faster rate of extinction of long-term contextual memory at 21 days of age, which was taken as evidence of enhanced inhibitory learning (i.e., context ??? no US) in these rats. Subsequent experiments with adult rats demonstrated that a combination of preweaning multisensory stimulation and postweaning rearing in an enriched environment improved the (1) specificity of long-term contextual memory, (2) speed of contextual information processing, and (3) availability of attentional resources. More specifically, enriched-reared rats demonstrated superior ability to discriminate between two similar contexts in comparison to standard-reared rats. In addition, enriched-reared rats showed superior memory of a context when there was limited time available to form a memory of that context. This finding was taken to indicate that rats that receive environmental enrichment are able to process contextual information more rapidly. Finally, standard-, but not enriched-, reared rats showed less conditioning to a discrete stimulus when it was presented in combination with a stronger stimulus during training compared to when it was presented by itself. The finding that enriched-reared rats did not show this overshadowing effect suggests that these rats have greater availability of attentional resources to divide between two stimuli that are competing for attention. The experiments with rats were followed by two experiments with children that investigated the effects of a computerised cognitive training procedure on information-processing speed. These experiments demonstrated that 30-minutes per weekday of training in rapid decision-making for three to five weeks improved children???s performance on two tests of processing speed (i.e., a choice reaction time and odd-man-out task). In addition, the speeded training improved children???s ability to sustain their attention and inhibit impulsive responses on a continuous performance test (Test of Variables of Attention). The cognitive training procedure had no effect on children???s performance on a measure of fluid intelligence (Raven???s Standard Progressive Matrices). The results of the experiments reported in this thesis suggest that a number of fundamental cognitive processes can be modified by environmental conditions that place increasing demands on the information-processing system. A neurobiological model, focusing on myelin, axon diameter, and the glutamatergic, glucocorticoid, noradrenergic, and cholinergic systems, was proposed in order to explain the observed effects of environmental stimulation on cognition in children and rats. The rationale for attempting to enhance fundamental cognitive processes was that improving these processes should ultimately improve general intellectual functioning. With respect to this aim, the correlational data from the present experiments with children revealed promising trends towards greater improvements on the tests of fundamental cognitive processes in those children in the training group with slower processing speed at the start of the intervention. This finding suggests that cognitive training may be even more effective at enhancing processing speed and other fundamental cognitive processes in children with intellectual impairments???who reportedly have slower processing speed than normal children. However, the extent to which training-related improvements in fundamental cognitive processes generalise to improvements in general cognitive functioning is unclear. That is, there is insufficient evidence that processing speed and other fundamental cognitive processes are causally related to intelligence. It is therefore essential that future cognitive training research is mindful of related developments within the intelligence and information processing literature.

Doctor of Philosophy / Zoological gardens, or zoos, keep and display wild animals, mainly for the purposes of education, conservation and biological research. However, it is evident that a significant component of zoos is the vast number of people who visit them, since without the support of visitors, zoos would not be financially viable and would cease to exist. This research investigates the behaviours of these visitors and develops an understanding of their awareness relating to what they see and do while they are in the zoo, along with their motivations for visiting. The study focuses on two major metropolitan zoos in Australia: Adelaide (in South Australia) and Taronga (in Sydney, New South Wales). A brief historical account contextualises changes, raising awareness of the significance of visitors to the livelihood of zoos. More and more zoos are integrating into their management routines different programmes that relate to the care and welfare of the animals. Despite recent growth in scientific attention, which has focused on human-animal relationships, little research has been conducted relating to the human visitor in the zoo. To date, decisions made by administrators have been based upon assumptions of the visitors’ understanding of the work of zoos rather than on actual quantitative findings. This empirical research is significant in that it uses both quantitative and qualitative methods to appraise factual data and information. The data from unobtrusive tracking observations at different exhibits, combined with the results of questionnaire surveys, are used to explore and assess the perceptions of visitors. In developing a demographic profile of the people who visit zoos, this work considers the motivations and the frequency of visitors. Various factors that influence the viewing patterns of visitors are explored to assess the popularity of exhibits, and the perceptions of visitors relating to animals and enclosures are investigated, to assess the diverse levels of satisfaction. Case studies explore the perceptions and understandings of visitors towards the use of enrichment items, the use of signs and labels, and a hypothetical approach to the feeding of carnivores in zoos. The results are important in that they contribute essential knowledge that describes the perceptions of a wide range of people who visit zoos, along with their expectations, since it is crucial for these institutions to maintain their popularity with the public.

Thesis (D. Min.)--Gordon-Conwell Theological Seminary, 1996. / Abstract and vita. Includes bibliographical references (leaves 129-133).

Diss. (sammanfattning) Alnarp : Sveriges lantbruksuniv. / Härtill 5 uppsatser.

Thesis (M.Ed.(Curriculum and Instructional Design and Development))-Universiteit van Pretoria, 2007. / Abstract in English. Includes bibliographical references. Available on the Internet via the World Wide Web.

Thesis (D. Min.)--Logos Evangelical Seminary, 2003. / Vita. Includes bibliographical references (leaves 427-442).

Thesis (Ed. D.)--Illinois State University, 1994. / Title from title page screen, viewed April 5, 2006. Dissertation Committee: Pamela H. Wheeler, Ming-Gon John Lian (co-chairs), Carol A. Thornton, Kenneth H. Strand, Maribeth N. Lartz. Includes bibliographical references (leaves 116-127) and abstract. Also available in print.

Thesis (Ed. D.)--Illinois State University, 2000. / Title from title page screen, viewed May 9, 2006. Dissertation Committee: Dent M. Rhodes (chair), Paul J. Baker, Wayne Benenson, Susan Lenski. Includes bibliographical references (leaves 130-132) and abstract. Also available in print.

Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.