My research explores the complex strategies animals adapt to cope with multiple selection pressures. I studied the behavioral and color response of two salamander sister species, Ambystoma barbouri and A. texanum, to temperature, predation risk and ultraviolet radiation (UVR, 280-320 nm). Ambystoma barbouri undergo development in streams, while A. texanum larvae inhabit ponds. Thus, A. barbouri are exposed to increased habitat ephemerality, enhanced predation risk, and UVR exposure. I show how A. barbouri have evolved alternate coping mechanisms in response to these environmental factors, relative to A. texanum. In this comparison study, I've quantified the affects of these selection pressures on larval color change, refuge use and depth choice.I found Ambystoma barbouri to have a significantly darker mean color than A. texanum. Additionally, both species significantly change color to match their background and in response to temperature. When exposed to warm temperatures, early-stage larvae of both species became lighter. Both species also changed color over ontogeny, with larvae becoming significantly lighter over development. Remarkably, A. texanum larvae mediated risk from predatory fish chemical cues by visually assessing the degree to which they cryptically match their background. If cryptic, A. texanum larvae remained on that background color rather than in refuge. A. barbouri larvae preferred to hide in refuge or on dark backgrounds regardless of crypticity, butquickly change color to match their new background. I found that both species darken in response to UVR. When given the choice of refuge, both species spent significantly more time in hiding when UVR was present. When given a choice of water depth, larvae preferred deep water in the presence of UVR radiation.Adapting multiple color and behavioral responses to individual selection pressures help organisms mediate conflicting demands from multiple selection pressures. For example, when predatory fish are present, larvae should move to shallow water to avoid predation. In the presence of UVR, however, larvae should prefer deeper water. I found A. barbouri larvae choose deep water to avoid high UVR exposure despite the risk of predation. Evolving multiple behavioral strategies allows A. barbouri larvae to avoid UVR damage and mediate predation risk.

The viscosity and density of bis(8-methylnonyl) benzene-1,2- dicarboxylate {diisodecyl phthalate (DIDP)}, with a nominal viscosity at T = 298 K and p = 0.1 MPa of 87 mPa•s, have been measured at temperatures from (298.15 to 423.15) K and pressures from (0.1 to 70) MPa. A vibrating wire viscometer, with a wire diameter of about 0.15 mm, was utilised for the viscosity measurements and the results have an expanded uncertainty, (k = 2), including the error arising from the pressure measurement, of between ±(2 and 2.5) % The density was determined with two vibrating tube densimeters one for operation at p≈0.1 MPa with an expanded uncertainty (k = 2) of about ±0.1 %, the other that used at pressures up to 70 MPa, with an estimated expanded uncertainty (k = 2) of about ±0.3 %. Measurements of density and viscosity were performed on three samples of DIDP each with different purity stated by the supplier and as a function of water mass fraction. The measured viscosity and density are represented by interpolating expressions with differences between the experimental and calculated values that are comparable with the expanded (k = 2) uncertainties. The obtained viscosities at p = 0.1 MPa agree with values reported in the literature within the combined expanded (k = 2) uncertainties of the measurements while our densities differ by no more than 1.5 %. Viscosity data at p > 0.1 MPa deviate systematically from the literature values in the range of -10 % to 10 %. An apparatus capable of simultaneously measuring the solubility of a gas dissolved in a liquid and the viscosity and the density of the resulting mixture over a wide temperature and pressure range was constructed and tested. Preliminary results have been reported.

Este trabalho apresenta o desenvolvimento e exemplos de aplicação de um software para cálculo de fluxo e pressões em silos cilíndricos metálicos de produtos agrícolas e industriais. As propriedades dos produtos a granel variam amplamente, e consequentemente suas pressões, tanto em grandeza e distribuição. Esses cálculos são importantes para prever picos de pressões imprevisíveis que podem causar sérios danos. O software está desenvolvido em linguagem Python com embasamento nas formulações do BS EN 1991-4 para silos esbeltos, medianamente esbeltos e baixos, com e sem excentricidades de carregamento e descarregamento, tremonhas cônicas, piramidais quadráticas, em forma de cunha ou de saída retangular dos tipos íngreme, rasa ou fundo plano. O programa é rápido, confiável, modular, estruturado e de fácil manuseio. A interface do software é simples para interação entre os dados fornecidos pelo usuário, tais como propriedades dos produtos armazenados, propriedades geométricas do silo e da tremonha, e os resultados obtidos das pressões e determinação do tipo de fluxo. São desenvolvidos exemplos de aplicação e análise dos resultados em silos cilíndricos metálicos de chapa corrugada muito comuns de uso em fazendas e cooperativas. Espera-se fornecer uma importante ferramenta para projetistas e desta forma criar projetos de silos mais eficientes, diminuindo falhas e colapsos. / This paper presents the development and application examples of software for calculation of pressures and flow in metal cylindrical silos of agricultural and industrial products. The properties of bulk materials vary widely, and consequently pressures, both in magnitude and distribution. These calculations are important to avoid peak unpredictable pressures that may cause serious damage. The software is developed in Python with grounding in the formulations of BS EN 1991-4 for silos slender, intermediate slenderness and squat, with and without loading and unloading eccentricities, conical and square pyramidal hoppers, wedge hoppers and hoppers of rectangular planform, shallow, steep or flat bottom. The program is fast, reliable, modular, structured and easy to handle. The software interface is simple for interaction between the data provided by the user, such as properties of stored products, geometric properties of the silo and hopper, and the results of the pressures and determining the type of flow. Are developed application examples and analysis of results in very common corrugated sheet metal cylindrical silos use in farms and cooperatives. It is expected to provide an important tool for designers and thus be more efficient silo designs, reducing failures and breakdowns.

Barragens são utilizadas há séculos para diversas finalidades. Em diversas barragens os vertedouros são constituídos de degraus com o objetivo de aumentar a dissipação de energia. A presente pesquisa objetiva a caracterização dos esforços atuantes em vertedouros em degraus, através da análise da variação das pressões atuantes ao longo da calha e suas distribuições na faces do degraus. Com esse objetivo, são realizadas análises sobre modelos de vertedouros com declividade de 1V:0,75H e degraus de 3, 6 e 9 centímetros. São analisados os campos de pressões nos degraus e comparados com os resultados disponíveis na bibliografia. Também são propostos modelos para previsão de pressões nos patamares e espelhos dos degraus bem como dos esforços resultantes. Além disso, são realizadas transposições dos resultados para a escala de protótipo, inclusive com a análise da possibilidade de cavitação na estrutura. Como constatação geral sobre as pressões nos espelhos verifica-se que os esforços de tração e compressão têm magnitudes relativamente semelhantes, sendo mais intensas as pressões negativas. Sobre as pressões máximas nos patamares, destaca-se que os valores máximos de compressão ocorreram no final da calha, percebendo-se que as menores vazões geraram maiores valores de coeficientes de pressões. As variações da compressão nas faces dos patamares apresentam crescimento, no sentido da extremidade com o espelho acima deste para o vértice com o espelho abaixo do mesmo patamar. Nas faces dos espelhos, percebe-se que os mais extremos de tração são observados na parte superior, próximo à quina com os patamares. / Dams have been used throughout the centuries for a plethora of purposes. Several designs employ steps on the spillways in order to increase the power dissipation. The present research aims to characterize the forces acting on stepped spillways by analyzing both the variation of pressures acting along the pipeline and their distributions on the faces of the steps. In order to achieve this purpose, observations and discussions regarding spillways models with slope characterized as 1V: 0.75H and steps ranging from 3 to 9 centimeters are conducted. The pressure fields measured in the steps were analyzed and compared with results available in the literature. Sub sequentially, models to predict pressures on the faces of the steps and the resulting efforts were proposed. Finally, transpositions were performed on a prototype scale. Generally, it was found that the magnitude of tensile and compressive forces on the vertical faces are relatively similar, being the negative pressure slightly higher on all cases. During the experiments, it was observed that compression forces increased thought the length of the step’s horizontal face, peaking at the edge. It was also noticed that lower flows generated higher pressure coefficients. The measured compression on the horizontal faces of the step and its variation increase towards the edge of the step. It is perceived that the maximum tensile is observed on the top of the step’s vertical faces, near the corner with the horizontal faces.

Of all anthropogenic pressures, urbanisation is one of the most damaging, and is expanding in its influence throughout the world. In Australia, 90% of the human population live in urban centres along the eastern seaboard. Before European settlement in the early 1800s, much of the Australia's East coast was dominated by forests. Many of the forest dependent fauna have had to adapt to forest fragmentation and habitat loss resulting from clearing for urbanisation. However, relatively few studies have investigated the impact of urbanisation on biodiversity. This is especially true for the remaining fauna in large metropolitan areas, such as Melbourne, Sydney and Brisbane. The physical and conceptual context of this thesis is the increasing impact of urbanisation and the potentially threatening factors to forest dependent fauna. Bats were selected because they comprise a third of Australia's mammal species, and therefore form a major component of Australia's biodiversity. Very little is known about the ecology and conservation biology of hollow-dependent bats in general, but particularly in urban environments. The study was conducted in Brisbane, south-east Queensland, one of Australia's most biodiverse regions. More than a third of Australia's bat species occur in this region. A large insectivorous bat, the white-striped freetail bat (Tadarida australis), was selected to study two key resources in this urban area - hollow availability and foraging habitat. This thesis also examined if artificial roost habitat could provide temporary roosts for white-striped freetail bats and other insectivorous bats and assessed whether these bat boxes can be used as a conservation tool in urban environments where natural hollow-availability is limited. The white-striped freetail bat is an obligate hollow-dweller and roosted largely in hollows of old or dead eucalypts throughout Brisbane's urban matrix. These roost trees harboured significantly more additional hollow-dependent species compared to control trees of similar age, height, and tree diameter. Roost cavities inside trees often exceeded 30 cm in diameter. Furthermore, maternity colonies used cavities of hollow trunks, which often extended into major branches, to roost in big numbers. Therefore artificial alternatives, such as small bat boxes, may provide temporary shelter for small roosting groups, but are unlikely to be suitable substitutes for habitat loss. Although five bat species used bat boxes during this study, the white-striped freetail bat was not attracted into bat boxes. Roost-switching behaviour was then used to quantify associations between individual white-striped freetail bats of a roosting group. Despite differences in gender and reproductive seasons, the bats exhibited the same behaviour throughout three radio-telemetry periods and over 500 bat-days of radio-tracking: each roosted in separate roosts, switched roosts very infrequently, and associated with other tagged bats only at a communal roost. Furthermore, the communal roost exhibited a hub of socialising between members of the roosting group especially at night, with vocalisation and swarming behaviour not found at any of the other roosts. Despite being spread over a large geographic area (up to 200 km2), each roost was connected to others by less than three links. One roost (the communal roost) defined the architecture of the network because it had the most links. That the network showed scale-free properties has profound implications for the management of the habitat trees of this roosting group. Scale-free networks provide high tolerance against stochastic events such as random roost removals, but are susceptible to the selective removal of hub nodes, such as the communal roost. The white-striped freetail bat flew at high speed and covered large distances in search for food. It foraged over all land-cover types found in Brisbane. However, its observed foraging behaviour was non-random with respect to both spatial location and the nature of the ground-level habitat. The main feeding areas were within three kilometers of the communal roost, predominantly over the Brisbane River flood plains. As the only mammal capable of flight, bats can forage above fragmented habitats. However, as this study showed, hollow-dependent insectivorous bats, including free-tailed bats, are specialised in their roosting requirements. The ongoing protection of hollow-bearing trees, and the ongoing recruitment of future hollow-bearing trees, is essential for the long-term conservation of these animals in highly fragmented landscapes. Furthermore, loss of foraging habitat is still poorly understood, and should be considered in the ongoing conservation of bats in urban environments.

Thesis (M.Phil.) - University of Queensland, 2006. / Includes bibliography.

The purpose of this study was to explore protective factors that help women resist societal pressures for thinness. The present study used a qualitative life history methodology to examine the experiences of women who identified themselves as resilient to pressures to be thin and as liking their bodies regardless of size. In-depth semi-structured interviews were conducted with 14 women, ages 18 to 25, representing diverse social and ethno-cultural backgrounds and body physiques. In the interviews, the participants were inquired about their experiences related to anything they felt was helpful for them in developing a positive body image from childhood, adolescence, and to present day. The interviews were transcribed and analyzed for themes using constructivist grounded theory methodology. Data analysis was informed by the feminist theoretical approach, with attention paid to social and contextual factors. Three core categories emerged from the analysis, which included protective factors associated with participants’ experiences of identity, ways of inhabiting their bodies, and the nature of social influences in their lives. This research highlighted the women’s active role in maintaining a resilient stance in the face of pressures for thinness as well as the importance of social factors that assist them in this process.

When operating microsystems in harsh environments, many conventionally used techniques are limiting. Further, depending on if the demands arise from the environment or the conditions inside the system, different approaches have to be used. This thesis deals with the challenges encountered when microsystems are used at high pressures and high temperatures. For microsystems operating at harsh conditions, many parameters will vary extensively with both temperature and pressure, and to maintain control, these variations needs to be well understood. Covered within this thesis is the to-date strongest membrane micropump, demonstrated to pump against back-pressures up to 13 MPa, and a gas-tight high pressure valve that manages pressures beyond 20 MPa. With the ability to manipulate fluids at high pressures in microsystems at elevated temperatures, opportunities are created to use green solvents like supercritical fluids like CO2. To allow for a reliable and predictable operation in systems using more than one fluid, the behavior of the multiphase flow needs to be controlled. Therefore, the effect of varying temperature and pressure, as well as flow conditions were investigated for multiphase flows of CO2 and H2O around and above the critical point of CO2. Also, the influence of channel surface and geometry was investigated. Although supercritical CO2 only requires moderate temperatures, other supercritical fluids or reactions require much higher temperatures. The study how increasing temperature affects a system, a high-temperature testbed inside an electron microscope was created. One of the challenges for high-temperature systems is the interface towards room temperature components. To circumvent the need of wires, high temperature wireless systems were studied together with a wireless pressure sensing system operating at temperatures up to 1,000 °C for pressures up to 0.3 MPa. To further extend the capabilities of microsystems and combine high temperatures and high pressures, it is necessary to consider that the requirements differs fundamentally. Therefore, combining high pressures and high temperatures in microsystems results in great challenges, which requires trade-offs and compromises. Here, steel and HTCC based microsystems may prove interesting alternatives for future high performance microsystems.

Surge modeling is a tool used by engineers and utility owners in determining the surge pressures or transients that may result from routine pump and valve operations. Recent surge modeling work has focused on low and/or negative pressures within water distribution systems and how those occurrences could lead to intrusions. Effective surge modeling is needed in order to determine if the intrusion potential exists and what mitigation is needed to prevent intrusions. This work focuses on the generally unexplored area of using surge models to predict the location and duration of transient induced low and/or negative pressures within large complex water distribution systems. The studied system serves 350,000 people in the southeast United States, has 65 MGD of pumping capacity at two treatment plants, over 1500 miles of main and 12 storage tanks. This work focuses on the correlation between field data and the surge model using the author's extensive operational knowledge of the system, access to real-time SCADA data, and different celerity or wave speed values. This work also traces the steps taken by the author to locate areas within the system that experienced transient induced low and / or negative pressure.

The purpose of this study was to explore protective factors that help women resist societal pressures for thinness. The present study used a qualitative life history methodology to examine the experiences of women who identified themselves as resilient to pressures to be thin and as liking their bodies regardless of size. In-depth semi-structured interviews were conducted with 14 women, ages 18 to 25, representing diverse social and ethno-cultural backgrounds and body physiques. In the interviews, the participants were inquired about their experiences related to anything they felt was helpful for them in developing a positive body image from childhood, adolescence, and to present day. The interviews were transcribed and analyzed for themes using constructivist grounded theory methodology. Data analysis was informed by the feminist theoretical approach, with attention paid to social and contextual factors. Three core categories emerged from the analysis, which included protective factors associated with participants’ experiences of identity, ways of inhabiting their bodies, and the nature of social influences in their lives. This research highlighted the women’s active role in maintaining a resilient stance in the face of pressures for thinness as well as the importance of social factors that assist them in this process.