Half model testing is considered a valuable wind tunnel technique that offers many benefits over conventional full span testing. The technique suffers from aerodynamic losses due to flow separations on the model surfaces near the model/floor junction. Computational Fluid Dynamics, employing the Spalart-Allmaras turbulence model, and experimental investigations were carried out to evaluate the losses and to investigate the effect of localised suction on the junction flows. The wind tunnel model used was a rectangular and untwisted wing having a NASA LS(1)-0413 cross section and with a physical aspect ratio of 3. Tests were conducted at 10.00 incidence at a Reynolds number of 0.44 x 106. Aerodynamic performance of the wind tunnel half model was obtained by surface flow visualisation and pressure measurements on the wing surface in the junction region. CFD predictions showed significantly large losses compared to the experimental findings and therefore CFD predicted significant influence and benefits of suction. These were seen as elimination of the model surface separation and also recovery of the wing surface pressure distributions. In contrast to this, experiments showed much smaller separation than CFD without suction and applying suction in experiments, showed only a marginal effect on the flow separations, which also further deteriorated the pressure distributions. Future CFD studies on junction flows should be conducted using more advanced turbulence models such as Large Eddy Simulations (LES). In addition, to validate these CFD studies, velocity and turbulence measurements in the wing/floor junction region are also needed.

ABSTRACT Odontogenic abscesses and Ludwig’s angina are infections commonly seen by maxillofacial surgeons. Both infections have periapical or periodontal origin and caused by oral bacteria. Ludwig’s angina is an aggressive and fast spreading infection compared to odontogenic abscess. The origin and the responsible bacteria of these infections are similar but the development and response is different in patients. There is no comprehensive study that has investigated the bacterial and host factors involved in the development of there infections. The aim of this study was to compare the presence of bacteria and enzymes in to the pus samples collected from patients with odontogenic abscess and Ludwig’s angina. Furthermore, various haematological and immunological tests were also compared between the two study groups. Forty two patients presenting with localized odontogenic abscesses and 15 with Ludwig’s angina were selected. Patient was examined according to standard protocol and history was recorded. Bloods were collected for haematology and immunology tests and pus was collected for microbiology and enzymatic tests. The results showed that highly virulent bacteria such as Staphylococcus aureus and black pigmented bacteroides were prevalent, increase in c-reactive protein, white blood cell count, IL6 and decrease in urea, circulating immune complexes and IgE in patients with Ludwig’s angina. Development of Ludwig’s angina could be due to the aggressive bacteria, their byproducts and low immune response compared to the odontogenic abscesses.

No description available.

No description available.

It is crucial for a building to maintain structural stability when subjected to multiple and sequential extreme loads. Safety and economic considerations dictate that structures are built to resist extreme events, such as a earthquakes, impacts, blasts or fires, without collapse and to provide adequate time for evacuation of the occupants. However, during such events, some structural damage may be permissible. Design codes do not account for the scenario where two extreme events occur consecutively on a structure nor do they address the situation of the structure having some initial damage prior to being subjected to a fire load. This work begins by detailing the major inconsistancies between designing reinforced concrete structures for extreme mechanical loads and designing for fire. The material behaviour and traits of the constitutive parts (i.e. the concrete and the steel), including post yielding behaviour, thermal relationships and their interaction with each other are all explored in detail. Comprehensive experimental and numerical investigations are undertaken to determine whether, and to what extent, phenomena such as tensile cracking and loss of the concrete cover affect the local and global fire resistance of a member or structure. The thermal propagation through tensile cracks in reinforced concrete beams is examined experimentally. A comparison is made between the rate of thermal propagation through beams that are undamaged and beams that have significant tensile cracking. The results show that, although small differences occur, there is no significant change in the rate of thermal propagation through the specimens. Consequently, it is concluded that the effects of tensile cracking on the thermal propagation through concrete can be ignored in structural analyses. Significantly this means that analyses of heated concrete structures which are cracked can be carried out with heat-transfer and mechanical analyses being conducted sequentially, as is currently normal and fully-coupled thermo-mechanical analyses are not required. The loss of concrete cover and the impact on the thermal performance is examined numerically. A comparison is made of the thermal propagation, beam deflections and column rotations between structures that are undamaged and structures that have partial cover loss in a variety of locations and magnitudes. Results show that any loss of cover can lead to unsymmetrical heating, causing larger deflections in both vertical and horizontal directions, which can result in a more critical scenario. It is concluded that the effect of cover loss on the thermal performance of the structure is extremely significant. A new approach to numerically simulating the loss of cover by mechanical means from a member is developed. This new approach provides the user with an extremely flexible yet robust method for simulating this loss of cover. The application of this method is then carried out to show its effectiveness. A large experimental study carried out at the Indian Institute of Technology, Roorkee and separately numerically modelled at the University of Edinburgh. Unfortunately, due to unforseen circumstances, the experimental data available is limited at this time and as a result the validation of the numerical simulation is limited. Through these investigations it is clear that it is necessary to develop a method in enhance the stability and integrity of the concrete when subjected to the scenario of a fire following another mechanically extreme event. Therefore, finally a method is proposed and experimentally investigated into the use of fibres to increase the post crushing cohesiveness of the concrete when subjected to thermal loads. Results show that the fibrous members display an increased thermal resistance by retaining their concrete cover through an enhanced post crushing cohesion. From this investigation, it is concluded that the use of fibrous concrete is extremely beneficial for the application of enhancing the performance under extreme sequential mechanical and thermal loading.

Free vibrations of a thin elastic circular cylindrical panel localized near the rectilinear edge, propagating along the edge and decaying in its circumferential direction, are investigated in the framework of the two-dimensional equations in the Kircho↵-Love theory of shells. At first the panel is assumed to be infinite longitudinally and semi-infinite along its length of curvature (of course not realistically possible), followed by the assumption that the panel is then finite along its length of curvature and fixed and free conditions are imposed on the second resulting boundary. Using the comprehensive asymptotic analysis detailed in Kaplunov et al. (1998) “Dynamics of Thin Walled Elastic Bodies”, leading order asymptotic solutions are derived for three types of localized vibration, they are bending, extensional, and super-low frequency. Explicit representation of the exact solutions cannot be obtained due to the degree of complexity of the solving equations and relevant boundary conditions, however, computational methods are used to find exact numerical solutions and graphs. Parameters, particularly panel thickness, wavelength, poisson’s ratio, and circumferential panel length, are varied, and their e↵ects on vibration analyzed. This analysis is further extended to investigate localized vibration on the interface (perfect bond) of two cylindrical panels joined at their respective rectilinear edges, propagating along the interface and decaying in the circumferential direction away from the interface. An earlier, similar, localized vibration problem presented in Kaplunov et al. (1999) “Free Localized Vibrations of a Semi-Infinite Cylindrical Shell” and Kaplunov and Wilde (2002) “Free Interfacial Vibrations in Cylindrical Shells” is replicated for comparison with all cases. The asymptotics are similar, however in this problem the numerics highlight the stronger e↵ect of curvature on the decay of the super-low frequency vibrations, and to some extent on the leading order bending vibration.

The subcellular localisation of mRNA is a widespread mechanism to determine the fate of mRNAs in eukaryotes. Translationally repressed mRNAs localise to P-bodies and stress granules where their decay and storage, respectively, are directed. In a study from the Ashe lab, specific mRNAs were identified to localise, in actively growing S. cerevisiae, to cytoplasmic granules that do not seem to be related to P-bodies or stress granules but appear to be associated with active translation (Lui et al., 2014).It is possible that this might represent a strategy to co-regulate the expression of proteins from the same pathway. In the work of this thesis, microscopy techniques to visualise RNAs in live cells were used to extend the localisation analysis to several mRNAs encoding translation factors. The investigated transcripts were all found to localise to mostly one or two cytoplasmic granules per cell and would sometimes overlap with other transcripts, suggesting that each granule contains a mixture of mRNAs. Granules tend to migrate to the bud tip and may provide the daughter cell with a "start-up kit" of transcripts essential for rapid growth. A similar pattern can be observed in yeast cells growing undergoing filamentous growth, with granules harbouring translation factor transcripts often found in the apical quarter of the elongated cell. Although the mechanism by which the granules form and their protein composition are not yet known, high-throughput genetic screens performed as part of this work offer some insight into factors that might be involved in granule assembly and proteins that partially overlap with the granules. We propose that granules containing translation factor mRNAs might be functioning as a specialised factory for the translation machinery and are possibly being directed to the point in the cell where the rhythm of protein production is highest.

In terms of developing knowledge to enable more effective use of performance based engineering (PBE), one of the key limitations is the lack of an easy to use integrated computational tool that is also robust and comprehensive enough to enable automated modelling of more realistic fire scenarios, i.e., the structural response to localised or travelling fires. The main objective of this thesis is to establish such an integrated computational tool, which shall be based on the OpenSees software framework and facilitated by specially developed approaches to achieve higher efficiency of the integrated analysis. This includes the analysis of heat transfer from the fire to structural members, as well as the analysis of structural response to elevated temperatures during the fire. In this thesis, the research begins with the investigation of the feasibility of dimensional reduction for heat transfer analyses of structural members subjected to localised fire action (SFPE and Eurocode 1 fire models), which can be numerically represented by a linear or exponential correlation between incident heat flux and radial distance. Accurate estimates of the error induced by dimensional reduction are presented under strongly varying localised heat fluxes that represent the most non-uniform fire conditions in a building compartment. It is shown that beams and slabs can be adequately modelled with a lower dimensional heat transfer analysis for ordinary building fires. Using this approach, the complexity of heat transfer modelling and the required computing resource and user effort can both be significantly reduced, especially in cases where structural members are subjected to localised fire action. Thermo-mechanical simulations are presented to address the behaviour of structural members subjected to localised fire action, for which a ThermalAction- Wrapper is developed to approximate the temperature distribution from a mixed-order interpolation between sections (beam) or locations (slab). For concrete slabs subjected to localised fire, MITC4 based shell elements are used to account for material and geometric nonlinearities. An integrated simulation environment is developed, which is designed to be a computational tool that requires limited input but provides a comprehensive solution to the problem of simulating large structural frame and sub-frame response under realistic fire scenarios. A considerable amount of code has been written to create and operate the building model, and to process the heat fluxes from the design fires to the structure and the consequential structural response to the evolution of temperatures within it. Parametric studies have been performed to investigate the computational performance of the newly developed elements in modelling beams and slabs subjected to different cases of localised fire action. The results suggest that 3 to 6 force-based beam elements can adequately describe the localised response however more elements are required for quadratic distribution of incident heat flux and higher temperatures, which is due to the degradation of material strength that governs the accuracy especially when the members are heavily loaded. For slabs exposed to localised fires, centre fires are found to produce greater deflections than corner fires, while lateral restraints applied to the slabs may also lead to higher deflections. A small-scale three dimensional structural frame is modelled as a demonstration of the tool, tested against a number of localised fire scenarios. The global behaviour of the structure with the local effects induced by the fire action and partially damaged fire protection are investigated. Severe damage can be found in the members exposed to a single whole compartment fire, in contrast with the relatively small deflections that are observed when a fully protected column is engulfed by a localised fire. However if the passive fire protection is partially damaged, collapse may occur in the column as a result of load magnification because of the redistribution. To the author's knowledge this is the first piece of research that has been able to develop a practically feasible approach to enable efficient coupled computation of the response of structural frames to realistic fire scenarios on a freely available open source software platform. Currently this kind of analysis can only be carried out by just two or three large consulting firms because of the prohibitive commitment of analyst time and effort and to a lesser extent the need for significant computing resources. The work of this thesis will contribute enormously towards making high-end performance based engineering of structural fire resistance a much more practical proposition for small and medium size structural consultancies. Furthermore, the choice of OpenSees, which is a very well respected software framework for simulating structural response to earthquakes naturally enables this work to be extended to the simulating the multi-hazard structural resistance, such as in the event of a fire following an earthquake which may have locally damaged passive fire protection.

The research reports on an ethnographic study undertaken at Kingswood, a secondary school in the North West of England, during a period of rapid reform within educational policy-making in England. The research project sets out to offer an empirical account of localised policy-making and a conceptual analysis as to how and why different social actors within and connected to the school are positioned and position-take in response to the schools’ localised development trajectory. In order to do this, the study operationalises Bourdieu’s thinking tools of field, capital and habitus as a means of theorising the complex relationship between structure and agency in the processes of localised policy-making. In order to present a detailed analysis of the positioning and position-taking I develop and deploy the conceptualisation of the neoliberal policy complex. I use this to describe and understand how the political and economic fields of production penetrate localised decision-making in which the connected agendas of performativity and accountability frame much of the localised policy processes at the research site. The neoliberal policy complex is defined by an on-going and increased commitment to legislative interventions, not least through an approach to the modernisation of public service in which autonomy and diversification are hailed as hallmarks for success. Drawing on data collected in a year long embedded study, from interviews and, observations with 18 students, five parents, 21 teachers, and seven school leaders, and documentary analysis, it is argued that within this neoliberal policy complex, the field of power is located as a centralising force in structuring the policy-making development and enactments at the local level. In order to achieve distinction within the schooling field and thus be acknowledged as legitimate within the neoliberal policy complex, Kingswood’s localised development trajectory reveals how the discourses of neoliberalism have been internalised by the social actors within the study, to produce subjective positioning which reveals a commitment to the neoliberal doxa. Within this theorisation certain knowledges, capitals and ways of doing and thinking are privileged and presented as common sense. At Kingswood, the conversion to an academy in April 2012 and the attendant re-organisation of the school provision into a Multi-Academy Trust, which has on site a ‘professional’ and a ‘studio’ school, are presented as a necessary construction for the school’s future, and the employability skills that will be subsequently embedded within the curriculum are framed as a common sense development of the purposes of education. The study concludes that such position-taking ultimately reveals how the centralising and hierarchical notions of power work to produce a narrative of misrecognition with regards to how the school must develop localised policy-making in order to remain a viable and legitimate entity in the schooling field. The research makes a contribution to the field of policy scholarship by applying Bourdieu’s thinking tools to the empirical findings from a range of social actors in and connected to the school in order to construct an understanding of the relationships between power and positionality in localised policy-making in neoliberal times.

Fusion welding processes cause residual stress due to the uneven heat distribution produced by the moving welding torch. These residual stresses are characterised by a large tensile component in the welding direction. Due to the self-equilibrated nature of the residual stress, compressive ones are present in the far field next to the weld seam, which can cause different kind of distortion such as bending or buckling. Welding residual stress can be responsible of premature failure of the components, such as stress crack corrosion, buckling, and reduction of fatigue life. Localised rolling is a stress engineering technique that can be used to reduce the residual stress and distortion caused by welding. It induces plastic strain in the rolling direction, counteracting the plastic strain produced during welding. In this thesis three techniques were investigated, pre-weld rolling, post-weld rolling, and in situ rolling. These techniques have been seldom studied in the past, particularly pre-weld rolling; consequently the mechanisms are poorly understood. Finite element models allow stress and strain development during both welding and rolling processes to be better understood, providing an improved understanding of the mechanisms involved and aiding process development. A literature survey was done to find the state of the art of the computational welding mechanics simulations, stress management, and the residual stress measurement techniques, as well as the knowledge gaps such as, the thermal losses through the backing-bar in the thermal simulation, the frictional interaction in the rolling process, and the material properties of the steel used in the models. In the literature not many models that investigate the management of welding residual stress were found. After this, the general considerations and assumptions for the welding thermal mechanical models presented in this thesis were discussed. The effect of different backing-bar conditions, as well as different material properties where investigated. Both influenced the residual stress profile to varying degrees. In particular, temperature dependent heat loss to the backing-bar was necessary to capture the improved heat loss near the weld. The distortion predicted by the model was investigated to determine whether it was due to bending or buckling phenomena. Lastly, the temperature distribution and residual stress predictions were validated against thermocouple and neutron diffraction measurements conducted by Coules et al. [1–3]. Pre-weld rolling was the first of the three rolling methods considered, in which rolling is applied to the plates before performing GMA butt-welds. The principle behind this technique consisted in inducing tensile residual stress in the weld region before welding; therefore, it is similar to mechanically tensioning the weld, which can significantly reduce the residual stress and distortion. However, there was no significant change in the tensile residual stresses. On the other hand, it was possible to achieve a small reduction in the distortion, when the plates were rolled on the opposite surface to the weld; rolling in this way induced distortion in the opposite direction to the distortion induced by welding, reducing the magnitude of the latter. These results were compared with experiments conducted by Coules et al. [1,4]. A subsequent investigation combined pre-weld rolling with post-weld heating. With this additional process the residual stress and distortion were significantly reduced, and flatter residual stress profile was achieved. The post-weld rolling and in situ rolling techniques were discussed afterwards. In the post-weld rolling models, rolling was applied after the weldment was cooled to room temperature. In in situ rolling the roller was applied on top of the weld bead at some distance behind the torch, while it was still hot. The principle behind these techniques consisted in applying positive plastic strain to the weld bead region by a roller, counteracting the negative plastic strains produced in the welding process. Two roller profiles were investigated, namely, grooved, and double flat rollers. The post-weld rolling on top of the weld bead models, which used the grooved roller, showed good agreement against experimental results, producing a large reduction of the residual stress and distortion. Some discrepancies were present when the weld toes were rolled with the dual flat roller. The former roller was more efficient for reducing residual stress and distortion. The influence of different friction coefficients (between the roller and weldment, and between the backing-bar and the weldment), were investigated. It showed significant dependency on the residual stress distribution when high rolling loads were used. The frictional interaction constrained the contact area inducing more compressive stress in the core of the weld bead; therefore it produced more tensile residual stress in the surface of the weldment. Additionally, the influence of rolling parameters on the through-thickness residual stress variation was investigated. Low loads only influence the residual stress near the surface, while high loads affected the material through the entire thickness. When the dual flat roller was used to roll next to the weld bead, significant compressive residual stress was induce in the weld bead; however, the residual stress reduction was very sensitive to the contact of the roller to the weld toes; therefore, when rolling a weld bead that varies in shape along the weld, the residual stress reduction is not uniform and varies along the length. On the other hand, the in situ rolling did not produced significant residual stress or distortion reduction in all the cases analysed. The rolling occurred when the material was still hot and the residual stress was subsequently formed as the material cooled to room temperature. Numerical modelling was a very useful tool for understanding the development of stress and plastic strain during the welding and rolling processes.