Junction flows originate from the interaction between a fluid moving over a wall with an obstacle mounted on the same surface. Understanding the physics of such flows is of great interest to engineers responsible for the design of systems consisting of wall-body junctions. From aerodynamics to turbomachinery and electronics to bridge hydraulics, a number of phenomena (drag, heat transfer, scouring) are driven by the behavior of the most prominent feature of junction flows: the horseshoe vortex system (HVS). Focusing on turbulent flows, the complex dynamics of the HVS is established through its unsteadiness and non-uniformity. The fundamentals of this dynamically-rich phenomenon have been described within the body of a rapidly-expanding literature. Nevertheless, important aspects remain inadequately understood and call for further scrutiny. This study emphasized three of them, by investigating the effects of: model scale, wall roughness, and bed geometry. High-resolution experiments were carried out using Particle Image Velocimetry (PIV). Statistical analyses, vortex identification schemes, and Proper Orthogonal decomposition were employed to extract additional information from the large PIV datasets. The time-averaged topology of junction flows developing over a smooth and impermeable wall was independent of the flow Reynolds number, Re (parameter that expresses the effects of scale). On the contrary, time-resolved analysis revealed a trend of increasing vorticity, momentum, and eruptions of near-wall fluid with Re. New insights on the modal dynamics of the HVS were also documented in a modified flow mechanism. Wall roughness (modeled with a permeable layer of crushed stones) diffused turbulence and vorticity throughout the domain. This effect manifested with high levels of intermittency and spatial irregularity for the HVS. Energetic flow structures were also identified away from the typical footprint of the HVS. Finally, a novel implementation of PIV allowed for unique velocity measurements over an erodible bed. It was demonstrated that, during the initial stages of scouring, the downflow at the face of the obstacle becomes the dominant flow characteristic in the absence of the HVS. Notwithstanding modeling limitations, the physical insight contributed here could be used to enhance the design of systems with similar flow and geometrical characteristics. / Ph. D.

As human population grows and develops, more urban areas are expanding. Urbanisation has many impacts on the natural environment and one understudied pollutant is artificial light at night. The aims of this thesis were to examine the impacts of street lighting on bats and investigate the exposure of British bat species to artificial light at night and explored the mitigation option of part-night lighting. The current exposure of British bat species to artificial lighting was assessed using roost locations and population sizes from a long-term dataset (1997-2012) from the Bat Conservation Trust’s National Bat Monitoring Programme on seven bat species (Eptesicus serotinus, Myotis nattereri, Pipistrellus pipistrellus, P. pygmaeus, Plecotus auritus, Rhinolophus hipposideros and R. ferrumequinum). These data were combined with satellite imagery in roost sustenance zones and home ranges. Bat roosts were found in areas with brighter light levels than random locations for P. pipistrellus, P. pygmaeus and Plecotus auritus. Species that forage around streetlights (P. pipistrellus and P. pygmaeus) had significantly higher light levels in the landscape around their roosts than species which avoid street lit areas (R. hipposideros, M. nattereri and P. auritus). Colony size was negatively correlated with light levels. This study highlights that different species have different requirements in the landscapes around their roosts. To investigate landscapes effects of artificial light at night on the understudied light avoiding species R. ferrumequinum, eight maternity roosts were surveyed to explore the interaction between habitat features and street lighting. At each maternity roost, bat detectors were deployed at 25 paired street lit and dark locations. Street lighting had a significant negative effect on bat activity. Locations closest to the maternity roost had higher bat activity than those further away and road type had a significant effect on bat activity, with the highest bat activity recorded at minor roads compared with A and B roads. These results highlight the large negative impact street lighting can have on bat activity patterns and the need for mitigation. Several mitigation strategies have been suggested to combat the effects of artificial light at night but few have been tested. One of these suggestions is to restrict the hours of lighting through the night, often called part-night lighting. Part-night lighting has been implemented by many local authorities, often switching the lights off after midnight and switching them back on before dusk. To explore the effects of part night lighting on bats, the hourly patterns of activity for R. ferrumequinum were studied. Bat activity was bimodal, with a peak in the first few hours after sunset followed by a smaller peak before sunrise. To capture more than 50% of bat activity during the dark period of the night, street lights would be required to switch off before 11pm. To explore this further, a before-and-after study of part-night lighting was conducted at towns across Devon. Following the conversion from full-night lighting to part-night lighting, switching street lights off at 2 am, there was a significant reduction in P. pipistrellus and a significant increase for P. pygmaeus and Nyctalus noctule activity. Although part-night lighting is not often operational during peak activity periods for bat species, reducing the duration of lighting at night has impacts on activity patterns for several species. This thesis shows that artificial light at night has impacts on bats across the landscapes around their roosts. Artificial lighting has impacts for species in different ways, depending on whether they forage around street lights or avoid street lit areas. For species that avoid street lit areas such as R. ferrumequinum, street lighting can have very significant negative impacts on the availability of areas around their roosts. This highlights the need for conservation measures to reduce impacts of artificial lighting. Although mitigation schemes such as part-night lighting may help to minimize impacts of nighttime lighting, more tailored schemes for bats should devised to achieve greater conservation impacts.

published_or_final_version / Microbiology / Doctoral / Doctor of Philosophy

Neste trabalho estudamos o valor mínimo da entropia topológica para uma classe de aplicações isotópicas à identidade em superfícies orientáveis (sem bordo, não necessariamente compactas e possivelmente de tipo finito) sob um ponto de vista estritamente topológico. Este estudo é feito utilizando a nova teoria de forcing para trajetórias transversas de Le Calvez e Tal que se baseia na teoria de Brouwer equivariante, em que é possível folhear superfícies com folhas relacionadas a teoria de Brouwer no plano. O principal resultado deste trabalho é uma melhora na estimativa da entropia topológica obtida por Le Calvez e Tal em um recente trabalho em que os autores buscam ferraduras topológicas em superfícies orientáveis utilizando ferramentas similares apresentadas aqui. Uma aplicação deste resultado acima é feita utilizando aplicações em S^2 que possuam um ponto fixo cuja trajetória pela isotopia deste ponto não seja homotópica a um múltiplo de um loop simples. Com estas hipóteses, melhoramos a estimativa dada por Le Calvez e Tal em que é encontrado um valor mínimo estritamente positivo para a entropia topológica desta aplicação. / In this work we study the minimum topological entropy value for one class of maps isotopics to the identity in oriented surfaces (without border, not necessary compacts and possibly of finite type) under the point of view strictly topological. This study is done using the new forcing theory to transverse trajectories from Le Calvez and Tal which it is based to equivariant Brouwer Theory, on what it is possible to leaf surfaces with leaves related to plane Brouwer theory. The main result in this work is a improvement in the estimates from the topological entropy obtained by Le Calvez and Tal in one recent work where the authors seek topological horseshoes on oriented surfaces using tools very similar to that are shown here. One application of the above result is done using maps on S^2 that have a fixed point whose trajectory by the isotopy of this point do not be homotopic to a multiple of a simple loop. With these hypotheses, we improve the estimates given by Le Calvez and Tal on what is found a strictly positive minimum value to the topological entropy of this map.

This thesis proposes a fresh engagement with the idea of the archaic as a means to recover and replenish some of the lost vitality suffered during what William Barrett characterized the modern period as “the gigantic externalization of life.” An introductory essay examines how the related ideas of the archaic, the primal, and the prehistoric have at key moments provided a source of creative energy for the arts of the last century. Collections of found material, and several photographic studies document the city of Niagara Falls—icon of American pop culture and faded relic of romanticism. The photographs present an alternative to the world of the touristic snapshot, and address the questions: In the age of simulation how do we know what is real anymore? Can we learn to see with archaic eyes?

This thesis proposes a fresh engagement with the idea of the archaic as a means to recover and replenish some of the lost vitality suffered during what William Barrett characterized the modern period as “the gigantic externalization of life.” An introductory essay examines how the related ideas of the archaic, the primal, and the prehistoric have at key moments provided a source of creative energy for the arts of the last century. Collections of found material, and several photographic studies document the city of Niagara Falls—icon of American pop culture and faded relic of romanticism. The photographs present an alternative to the world of the touristic snapshot, and address the questions: In the age of simulation how do we know what is real anymore? Can we learn to see with archaic eyes?

This study provides new insights on the mechanisms that controlled the development of solution-enhanced fractures and suprastratal deformation associated with the Mississippian Madison Sequence IV evaporite paleokarst complex. Based on detailed field mapping utilizing LiDAR, GPS, and field observations, we document a paleostructural high (oriented 145º) associated with the Ancestral Rockies uplift within the study area. One hundred twenty-one sediment-filled, solution-enhanced fractures within the Seq. IV cave roof were mapped and characterized by their dominant fill type (Amsden or Madison) and vertical extent. Spatial analysis reveals minimum spacing of these features occurs in areas uplifted during the Late Paleozoic suggesting a link between paleostructural position and solution feature spacing. Shape analysis of these solution features also supports structural position during the Late Paleozoic acted as a dominant control on fracture morphology: (1) downward tapering and fully penetrative features concentrate in areas that experienced uplift; (2) upward tapering concentrate in areas that were undeformed. Mapping of Seq. IV cave roof strata demonstrates vertical collapse variability exceeds 22 m and fault intensity increases in areas of increased collapse. These findings have significant implications for prediction and characterization of solution-enhanced fractures and suprastratal deformation within evaporite paleokarst systems. / text

Local scour around bridge foundations has been recognized as one of the main causes of bridge failures. The objective of this study is to investigate the relationships among field, laboratory, and numerical data for the purpose of improving scour prediction methods for complex bridge piers. In this study, three field sites in Georgia were selected for continuous monitoring and associated laboratory models were fabricated with physical scale ratios that modeled the full river and bridge cross sections to consider the effect of river bathymetry and bridge geometry. Three different sizes of sediment and several geometric scales of the bridge pier models were used in this study to investigate the scaling effect of relative sediment size, which is defined as the ratio of the pier width to the median sediment size. The velocity field for each bridge model was measured by the acoustic Doppler velocimeter (ADV) to explain the complicated hydrodynamics of the flow field around bridge piers as guided by the results from a numerical model. In each physical model with river bathymetry, the comparison between the results of laboratory experiments and the measurements of prototype bridge pier scour showed good agreement for the maximum pier scour depth at the nose of the pier as well as for the velocity distribution upstream of each bridge pier bent. Accepted scour prediction formulae were evaluated by comparison with extensive laboratory and field data. The effect of relative sediment size on the local pier scour depth was examined and a modified relationship between the local pier scour depth and the relative sediment size was presented. A useful methodology for designing physical models was developed to reproduce and predict local scour depth around complex piers considering Froude number similarity, flow intensity, and relative sediment size.

Orientador: Vanderlei Minori Horita / Banca: Ali Tahzibi / Banca: Paulo Ricardo Silva / Resumo: Estudamos intersecções homoclínicas de variedades estável e instável de pontos peródicos. Toda intersecção homoclínica produz um comportamento curioso na dinâmiôa. Nosso modelo de tal fenômeno é a famosa ferradura de Smale, a qual é um conjunto hiperbólico para um difeomorfismo. Além disso, estudamos dinâmica não hiperbólica cuja perda de hiperbolicidade é divido à tangências homoclínicas. Elas tem um papel central na teoria de sistemas dinâmicos. O desdobramento de uma tangência homoclínica produz dinâmicas muito interessantes. Neste trabalho estudamos a criação de cascatas de bifurcações de duplicação de período e um esquema de renormalização para uma tangência homoclínica. / Abstract: We study homoclinic intersection of stable and unstable manifolds of periodic points. Every homoclinic intersection produce a intricate behavior of the dynamics. Our model of such phenomena is the so called Smalesþs horseshoe, which is a hyperbolic set for a di eomorphism. We also study non hyperbolic dynamics whose lack of hyperbolicity is due to homoclinic tangencies. They play a central role in the theory of dynamical systems. The unfolding of a homoclinic tangency produce many interesting dynamics. In this work we study creation of cascade of period doubling bifurcations and a renormalization scheme for a homoclinic tangency. / Mestre

Ziel der Untersuchung war eine umfassende und vergleichbare Datengrundlage über den Einfluss verschiedener hauptsächlich orthopädischer Beschlagsmodifikationen auf die Ausrichtung der Zehenknochen, Druckverteilungsmuster und die individuelle Fußung unter Berücksichtigung unterschiedlicher klinisch relevanter Bodeneigenschaften zu generieren und mit Standardbeschlägen, sowie dem Barhuf zu vergleichen.:1 Einleitung 1 2 Literaturübersicht 3 2.1 Anatomie der distalen Gliedmaße des Pferdes 3 2.1.1 Knochen und Gelenke 3 2.1.2 Sehnen und Bänder 6 2.1.3 Der Huf und seine Segmente 10 2.1.3.1 Definition des Hufs 10 2.1.3.2 Der Hufbeinträger 10 2.1.3.3 Segmente des Hufs 11 2.2 Biomechanische Grundlagen 13 2.2.1 Allgemeine Betrachtungsweisen der Biomechanik 13 2.2.2 Die Statik der distalen Gliedmaße des Pferdes 15 2.2.3 Kinetische Betrachtung der distalen Gliedmaße des Pferdes 17 2.3 Analysemethoden biomechanischer Prozesse der distalen Gliedmaße des Pferdes 19 2.3.1 Statische Analysemethoden 20 2.3.1.1 Röntgen 20 2.3.2 Kinetische Analysemethoden 22 2.3.2.1 Druckmessung 22 2.4 Lahmheit und deren Ursachen im Bereich der distalen Gliedmaße 23 2.4.1 Definition des Begriffes Lahmheit und deren Erkennung 24 2.4.2 Risikofaktoren für die Entstehung von Lahmheit 25 2.5 Orthopädischer Beschlag 27 2.5.1 Erkrankungen der distalen Gliedmaße mit Beschlagsindikation 27 2.5.2 Beschlagsmodifikationen 28 2.5.2.1 Beschlagsmodifikationen der dorsopalmaren Ebene 29 2.5.2.2 Beschlagsmodifikationen der mediolateralen Ebene 34 2.5.3 Der Einfluss unterschiedlicher Bodeneigenschaften auf die Wirkung orthopädischer Beschlagsmodifikationen 36 3 Wissenschaftliche Originalarbeiten 38 3.1 Modifying the Surface of Horseshoes: Effects of Eggbar, Heartbar, Open Toe, and Wide Toe Shoes on the Phalangeal Alignment, Pressure Distribution, and the Footing Pattern 38 3.2 Modifying the Height of Horseshoes: Effects of Wedge Shoes, Studs, and Rocker Shoes on the Phalangeal Alignment, Pressure Distribution, and Hoof-Ground Contact During Motion 51 3.3 Modifying Horseshoes in the Mediolateral Plane: Effects of Side Wedge, Wide Branch, and Unilateral Roller Shoes on the Phalangeal Alignment, Pressure Forces, and the Footing Pattern 63 4 Diskussion 73 4.1 Material und Methoden 73 4.1.1 Röntgenuntersuchung 73 4.1.2 Druckmessung 75 4.1.3 Kombination von Röntgenuntersuchungen und Druckmessungen zur Beurteilung biomechanischer Fragestellungen 78 4.2 Die Veränderungen der Zehenknochenausrichtung nach Applikation von orthopädischen Beschlagsmodifikationen 79 4.3 Die Veränderungen des Druckverteilungsmusters unter Hufeisen und Huf nach Applikation von orthopädischen Beschlagsmodifikationen 81 4.4 Der Effekt von orthopädischen Beschlagsmodifikationen auf die individuelle Fußung 84 4.5 Schlussfolgerungen und Ausblick86 5 Zusammenfassung 88 6 Summary 90 7 Literaturverzeichnis 93 / Aim of this study was to establish comprehensive and comparable data groundwork on the influence of a variety of modified horseshoes on the alignment of the bone of the equine distal limb, pressure distribution and individual footing patterns, while considering different practically relevant flooring materials, in comparison to data acquired with standard horseshoes and barefoot examinations.:1 Einleitung 1 2 Literaturübersicht 3 2.1 Anatomie der distalen Gliedmaße des Pferdes 3 2.1.1 Knochen und Gelenke 3 2.1.2 Sehnen und Bänder 6 2.1.3 Der Huf und seine Segmente 10 2.1.3.1 Definition des Hufs 10 2.1.3.2 Der Hufbeinträger 10 2.1.3.3 Segmente des Hufs 11 2.2 Biomechanische Grundlagen 13 2.2.1 Allgemeine Betrachtungsweisen der Biomechanik 13 2.2.2 Die Statik der distalen Gliedmaße des Pferdes 15 2.2.3 Kinetische Betrachtung der distalen Gliedmaße des Pferdes 17 2.3 Analysemethoden biomechanischer Prozesse der distalen Gliedmaße des Pferdes 19 2.3.1 Statische Analysemethoden 20 2.3.1.1 Röntgen 20 2.3.2 Kinetische Analysemethoden 22 2.3.2.1 Druckmessung 22 2.4 Lahmheit und deren Ursachen im Bereich der distalen Gliedmaße 23 2.4.1 Definition des Begriffes Lahmheit und deren Erkennung 24 2.4.2 Risikofaktoren für die Entstehung von Lahmheit 25 2.5 Orthopädischer Beschlag 27 2.5.1 Erkrankungen der distalen Gliedmaße mit Beschlagsindikation 27 2.5.2 Beschlagsmodifikationen 28 2.5.2.1 Beschlagsmodifikationen der dorsopalmaren Ebene 29 2.5.2.2 Beschlagsmodifikationen der mediolateralen Ebene 34 2.5.3 Der Einfluss unterschiedlicher Bodeneigenschaften auf die Wirkung orthopädischer Beschlagsmodifikationen 36 3 Wissenschaftliche Originalarbeiten 38 3.1 Modifying the Surface of Horseshoes: Effects of Eggbar, Heartbar, Open Toe, and Wide Toe Shoes on the Phalangeal Alignment, Pressure Distribution, and the Footing Pattern 38 3.2 Modifying the Height of Horseshoes: Effects of Wedge Shoes, Studs, and Rocker Shoes on the Phalangeal Alignment, Pressure Distribution, and Hoof-Ground Contact During Motion 51 3.3 Modifying Horseshoes in the Mediolateral Plane: Effects of Side Wedge, Wide Branch, and Unilateral Roller Shoes on the Phalangeal Alignment, Pressure Forces, and the Footing Pattern 63 4 Diskussion 73 4.1 Material und Methoden 73 4.1.1 Röntgenuntersuchung 73 4.1.2 Druckmessung 75 4.1.3 Kombination von Röntgenuntersuchungen und Druckmessungen zur Beurteilung biomechanischer Fragestellungen 78 4.2 Die Veränderungen der Zehenknochenausrichtung nach Applikation von orthopädischen Beschlagsmodifikationen 79 4.3 Die Veränderungen des Druckverteilungsmusters unter Hufeisen und Huf nach Applikation von orthopädischen Beschlagsmodifikationen 81 4.4 Der Effekt von orthopädischen Beschlagsmodifikationen auf die individuelle Fußung 84 4.5 Schlussfolgerungen und Ausblick86 5 Zusammenfassung 88 6 Summary 90 7 Literaturverzeichnis 93