Improvements upon current gas turbine sealing technology performance are essential for decreasing specific fuel consumption to meet stringent future efficiency targets. The clearances between rotating and static components of a gas turbine, which need to be sealed, vary over a flight cycle. Hence, a seal which can passively maintain an optimum clearance, whilst preventing contact between itself and the rotor, is extremely desirable. Various configurations of a Rolls Royce (RR) seal concept, the Large Axial Movement Face Seal (LAMFS), use static pressure forces to locate face seals. Prototypes were tested experimentally at the Osney Thermofluids Laboratory, Oxford. Firstly a proof-of concept rig (simulating a 2-D seal cross-section) manufactured by RR was re-commissioned. The simplest configuration using parallel seal faces induced an unstable seal housing behaviour. The author used this result, CFD, and analytical methods to improve the design and provide a self-centring ability. A fully annular test rig of this new seal concept was then manufactured to simulate a 3D engine representative seal. The full annulus eliminated leakage paths unavoidable in the simpler rig. A parametric program of experiments was designed to identify geometries and conditions which favoured best-practice design. The new seal design is in the process of being patented by Rolls Royce. A 'fluidic' seal was also investigated, showing very promising results. A test rig was manufactured so that a row of jets could be directed across a leakage cross-flow. An experimental program identified parameters which could achieve a combined lower leakage mass flow rate compared with the original leakage. Influence of jet spanwise spacing, injection angle, jet to mainstream pressure ratio, mainstream pressure difference and channel height were analysed. It is hoped this thesis can be used as a tool to further improve these seal concepts from the parametric trends which were identified experimentally.

Through common descent, closely-related taxa share many life history traits, some of which can influence extinction-proneness. Thus, examining historical and contemporary genetic patterns is valuable in accounting for evolutionary and ecological processes that may be critical to the successful conservation of threatened species. Unsustainable harvesting of monk seals (tribe Monachini) until the late nineteenth century caused the recent extinction of Caribbean monk seals (Neomonachus tropicalis) and critically low population sizes for Hawaiian and Mediterranean monk seals (Neomonachus schauinslandi and Monachus monachus, respectively). Having lost one branch of its evolutionary lineage, and with a second branch threatened by extinction, the genus Neomonachus can serve as a valuable case for examining evolutionary and ecological linkages that are sensitive to non-random anthropogenic selection pressure. An important foundation for such pursuits is the understanding of evolutionary sequences of speciation and diversification that gave rise to common traits shared by extinct and vulnerable species. Further consideration of the phylogenetic non-randomness of species vulnerability requires examination of genetic variation at the population level to infer the presence of fundamental processes (e.g., migration and reproduction) that directly influence population viability. This dissertation includes three individual studies that make use of molecular systematic and population genetic techniques to address these topics. First, a complete mitochondrial genome sequence of the extinct Caribbean monk seal (N. tropicalis) was assembled and used to resolve long-standing phylogenetic questions regarding the sequence of divergence among monk seal species and sister taxa. Second, novel microsatellite marker assays were developed and used to characterize the extent of population-level variation across 24 polymorphic microsatellite loci of 1192 endangered Hawaiian monk seals (N. schauinslandi) that were sampled during a longitudinal study spanning three decades. Third, resulting genotypes from a subset of individuals (N= 785) were integrated with previously reported genotypes consisting of 18 other loci for the largest ever population-level assessment of N. schauinslandi genetic diversity and population differentiation throughout the Hawaiian archipelago. The new microsatellite data will be of particular value for future individual-level assessment of parentage and relatedness in N. schauinslandi, which will help managers better infer the reproductive mechanisms that factor into population persistence and recovery. Results of this study expand understanding of the evolutionary and conservation genetic status of monk seals, as well as molecular genetic capacity, for future research regarding a unique and highly imperiled New World pinniped lineage.

No description available.

Unlike municipal water supplies, provincial regulations do not require systematic testing of domestic well water, which may adversely impact local residents should contamination occur. Private wells are typically shallow relative to municipal wells, and thus, are particularly vulnerable to sources of surficial contamination if preferential recharge pathways such as natural fractures or faulty seals are present. In order to determine the relative importance of well seal integrity as a preferential pathway, a practical detection method was developed based on infiltrometry. This method successfully detected faulty well seals in a wide range of geological settings across Canada, including: Hobbema, Alberta; Lindsay, Ontario; and Chelsea, Québec. It was most successful in areas of minimal heterogeneity and where the surficial geology is composed of fine-grained sediments. The community of Chelsea (Québec) was also the primary study site to examine a range of factors affecting water quality including physical characteristics, faulty well seals, other anthropogenic activities and seasonality. Water samples were collected over a period of 14 months and analyzed for bacteria and major-ion chemistry. The results show that the consideration of physical features alone is not enough to predict vulnerability in the study area. Seasonal fluctuations in ionic concentrations (e.g. ionic strength, NO3-N and Cl-) and coliform bacteria are observed and result from disperse and rapid recharge events. Multivariate analysis techniques (e.g. principal components analysis and hierarchical cluster analysis) demonstrate that preferential recharge pathways and anthropogenic activities, such as domestic effluents affect the groundwater quality. The data and findings of this study were used to assist in the design of a probabilistic risk assessment model based on the Poisson distribution. This study demonstrates the complexity and the challenges related to bacterial contamination in drilled wells. In spite of these challenges, this analysis was useful as a baseline to assess the impact of anthropogenic activities, and may be used in future studies to assist municipalities in the evaluation and protection of groundwater supplies.

Unlike municipal water supplies, provincial regulations do not require systematic testing of domestic well water, which may adversely impact local residents should contamination occur. Private wells are typically shallow relative to municipal wells, and thus, are particularly vulnerable to sources of surficial contamination if preferential recharge pathways such as natural fractures or faulty seals are present. In order to determine the relative importance of well seal integrity as a preferential pathway, a practical detection method was developed based on infiltrometry. This method successfully detected faulty well seals in a wide range of geological settings across Canada, including: Hobbema, Alberta; Lindsay, Ontario; and Chelsea, Québec. It was most successful in areas of minimal heterogeneity and where the surficial geology is composed of fine-grained sediments. The community of Chelsea (Québec) was also the primary study site to examine a range of factors affecting water quality including physical characteristics, faulty well seals, other anthropogenic activities and seasonality. Water samples were collected over a period of 14 months and analyzed for bacteria and major-ion chemistry. The results show that the consideration of physical features alone is not enough to predict vulnerability in the study area. Seasonal fluctuations in ionic concentrations (e.g. ionic strength, NO3-N and Cl-) and coliform bacteria are observed and result from disperse and rapid recharge events. Multivariate analysis techniques (e.g. principal components analysis and hierarchical cluster analysis) demonstrate that preferential recharge pathways and anthropogenic activities, such as domestic effluents affect the groundwater quality. The data and findings of this study were used to assist in the design of a probabilistic risk assessment model based on the Poisson distribution. This study demonstrates the complexity and the challenges related to bacterial contamination in drilled wells. In spite of these challenges, this analysis was useful as a baseline to assess the impact of anthropogenic activities, and may be used in future studies to assist municipalities in the evaluation and protection of groundwater supplies.

The sense of smell in marine mammals is traditionally thought to be poor. However, increasing evidence suggests that pinnipeds may use their sense of smell in a variety of behavioral contexts including communication, foraging, food selection, and reproduction. Using a food-rewarded two-choice instrumental conditioning paradigm, I assessed the ability of South African fur seals, Arctocephalus pusillus, to discriminate between 12 enantiomeric odor pairs, that is, between odorants that are identical in structure except for chirality. The fur seals significantly discriminated between eight out of the twelve odor pairs (according to p < 0.05, with carvone, dihydrocarvone, dihydrocarveol, limonene oxide, menthol, beta-citronellol, fenchone, and alpha-pinene), and failed with only four odor pairs (isopulegol, rose oxide, limonene, and camphor). No significant differences in performance were found between the animals (p > 0.05). Cross-species comparisons between the olfactory performance of the fur seals and that of other species previously tested on the same set of odor pairs lend further support to the notion that the relative size of the olfactory bulbs is not a reliable predictor of olfactory discrimination abilities. The results of the present study suggest that sense of smell may play an important and hitherto underestimated role in regulating the behavior of fur seals.

<p>Infusing models for animal movement with more behavioral realism has been a goal of movement ecologists for several years. As ecologists have begun to collect more and more data on animal distribution and abundance, a clear need has arisen for more sophisticated analysis. Such analysis could include more realistic movement behavior, more information on the organism-environment interaction, and more ways to separate observation error from process error. Because landscape ecologists and behavioral ecologists typically study these same themes at very different scales, it has been proposed that their union could be productive for all (Lima and Zollner, 1996). </p><p>By understanding how animals interact with their land- and seascapes, we can better understand how species partition up resources are large spatial scales. Accordingly I begin this dissertation with a large spatial scale analysis of distribution data for marine mammals from Nova Scotia through the Gulf of Mexico. I analyzed these data in three separate regions, and in the two data-rich regions, find compelling separation between the different communities. In the northernmost region, this separation is broadly along diet based partitions. This research provides a baseline for future study of marine mammal systems, and more importantly highlights several gaps in current data collections.</p><p>In the last 6 years several movement ecologists have begun to imbue sophisticated statistical analyses with increasing amounts of movement behavior. This has changed the way movement ecologists think about movement data and movement processes. In this dissertation I focus my research on continuing this trend. I reviewed the state of movement modeling and then proposed a new Bayesian movement model that builds on three questions of: behavior; organism-environment interaction; and process-based inference with noisy data.</p><p>Application of this model to two different datasets, migrating right whales in the NW Atlantic, and foraging monk seals in the Northwest Hawaiian Islands, provides for the first time estimates of how moving animals make choices about the suitability of patches within their perceptual range. By estimating parameters governing this suitability I provide right whale managers a clear depiction of the gaps in their protection in this vulnerable and understudied migratory corridor. For monk seals I provide a behaviorally based view into how animals in different colonies and age and sex groups move throughout their range. This information is crucial for managers who translocate individuals to new habitat as it provides them a quantitative glimpse of how members of certain groups perceive their landscape.</p><p>This model provides critical information about the behaviorally based movement choices animals make. Results can be used to understand the ecology of these patterns, and can be used to help inform conservation actions. Finally this modeling framework provides a way to unite fields of movement ecology and graph theory.</p> / Dissertation

The northern fur seal (NFS) population on the Pribilof Islands (PI) is currently declining while the population on the Commander Islands (CI which includes Bering and Medny Islands) is stable. The reasons for the different population trajectories remain unknown. Comparing differences in behavioral ecology and predation pressure between these two populations could provide an explanation. This study examined lactating NFS female behavior to determine: 1) summer foraging patterns (trip duration, trip direction, dive depth) of animals from two nearby rookeries on Bering Island, 2) winter migration from Medny and Bering Islands relative to patterns of ocean productivity, and 3) the potential impact of killer whale predation on population dynamics. Data were collected from 2003 to 2010 using visual observations and telemetry. Twenty-one satellite transmitters, 29 time-depth recorders and 17 geolocation recorders were deployed. Shore-based observations of killer whale predation and photo-identification were conducted near the CI rookeries in 19992010. During lactation, both mean foraging trip duration and mean maximum diving depth (3.4 plus/minus 1.3 days and 17.7 plus/minus 6.8 m, respectively) for NFS adult females (n = 28) did not significantly change among years. Although foraging areas of NFS from the two rookeries on Bering Island overlapped, the mean direction of travel from Severo-Zapadnoe rookery was significantly (p<0.01) different compared with Severnoe rookery. The foraging patterns suggested that these females had a reliable food source that did not change despite potential environmental changes or the effects of fisheries. During their winter migration, NFS females from the CI traveled to the Transition Zone Chlorophyll Front (32° N-42° N) in the North Pacific Ocean. Their winter migration routes and the location of overwinter foraging areas were positively correlated with high ocean productivity (near surface chlorophyll a concentration). Over 82 percent (n=17) of these females spent 38 months near the eastern coast of Hokkaido, Japan and followed the coastal high productivity areas on their way back to the CI. Transient killer whales in groups of 2-12 individuals were repeatedly observed preying mostly on NFS males during the summer. The simulation model showed little impact on population dynamics as long as male fur seals were the primary prey. However, if the number of killer whales increased or they changed their diet to include females and pups, then the NFS population on the CI could decline. The winter migration of NFS from CI and PI are similar. Lactating NFS from the PI exhibit greater summer foraging effort (longer average trip duration and bout duration; greater number of deep dives) compared with females from the CI.

This dissertation considers an unfamiliar but fundamental aspect of late-medieval art: the role of documentation. Documents played as critical a part in that society as they do in our own. In late-medieval consciousness, the charter loomed as large as the sacred image, and documentation mattered no less than devotion—while the two also had a profound and inextricable connection. Discussion begins with three principal arguments, explained in detail in the first chapter: 1. The materials of documentation are part of the history of art; and accordingly, art-historical methods render an important contribution to diplomatics. 2. Documents are an important subject of representation; and accordingly, works of art are important sources for the cultural reception of documentary practices. 3. Documents are an important model for representation; and, consequently, an understanding of the paradigmatic role of the document suggests an alternative dimension to the interpretation of late-medieval art. The chapters that follow pursue these arguments through the analysis of individual works of art—charters, seals, archival manuscripts, liturgical manuscripts, architecture, and sculpture. These chapters also include a study of one of the great monuments of English gothic art: the Sherborne Missal, produced c.1400 for the Benedictine abbey of Sherborne. Ideas of documentation constitute critical aspects both of the Missal’s subject matter and its modes of representation, and these “documentary” elements also relate closely to the larger ideological project of the Missal’s creators. As details of the manuscript’s patronage, illumination, liturgy, inscriptions, and codicology all demonstrate, its creators associated documentation with central religious ideas about devotional images and the eucharist—essentially, the nature of valid representation and effective action. In keeping with the regional and institutional context of this principal study, the other objects discussed come primarily from English religious institutions. That context, however, by no means implies that the importance of documentation is limited either to England or to the conventual sphere, although it manifests itself differently from place to place and from one estate to another. The studies in this thesis represent only one example of where its arguments might lead, and what its approach might reveal in other works of art. / History of Art and Architecture

This thesis examines the biogeography of world pinnipeds, a unique group of marine mammals that have adapted to marine foraging while maintaining terrestrial (land or ice) habitat links. Comparative analyses of species range sizes controlled for phylogenetic relationships using a multi-gene supertree with divergence dates estimated using fossil calibrations. Adaptations to aquatic mating and especially sea ice parturition have influenced range size distribution, and ranges are larger than those of terrestrially mating and/or pupping species. Small range size is endangering for many taxa, and most at risk pinnipeds are terrestrial species with small ranges. Ancestral state reconstructions suggest that pinnipeds had a long association with sea ice, an adaptation that would have allowed early seals to expand into novel habitats and increase their distribution. Range sizes exhibit a strong Rapoport effect (positive relationship between range size and latitude) at the global scale, even after controlling for phylogeny and body size allometry. A latitudinal gradient in species diversity cannot explain the Rapoport effect for global pinniped ranges, as diversity is highest at mid-latitudes in both hemispheres. These regions are characterized by marginal ice zones and variable climates, supporting a mix of pagophilic and temperate species. The climatic variability hypothesis also did not explain the Rapoport effect. Variability is bimodal, and annual sea surface temperature (SST) variability does explain diversity patterns. Range size has a significant negative relationship with annual mean SST, and the largest ranges are found in areas with low mean SST. Temperature responses are possibly related to thermoregulation, sea ice availability, and ecological relationships with other large marine predators. These results agree with other studies and suggest that ocean temperature, and not productivity, drives marine species richness patterns. Future research needs include studies of physiological tolerances, interactions with sharks as predators and competitors, and the role of climate and sea ice in speciation and evolution. A better understanding of distribution and diversity patterns, and the role of the environment in shaping these patterns, will improve conservation efforts, and studies on the role of SST and sea ice are particularly important given current warming trends and declines in ice extent.