An experimental program is designed to study the salient features of separated and reattached flows in pressure gradients generated in asymmetric diverging and converging channels. The channels comprised a straight flat floor and a curved roof that was preceded and followed by straight parallel walls. Reference measurements were also made in a parallel-wall channel to facilitate the interpretation of the pressure gradient flows. A transverse square rib located at the start of convergence/divergence was used to create separation inside the channels. In order to simplify the interpretation of the relatively complex separated and reattached flows in the asymmetric converging and diverging channels, measurements were made in the plain converging and diverging channel without the rib on the channel wall. All the measurements were obtained using a high resolution particle image velocimetry technique. The experiments without the ribs were conducted in the diverging channel at Reynolds number based on half channel depth (Reh) of 27050 and 12450 and in the converging channel at Reh = 19280. For each of these three test conditions, a high resolution particle image velocimetry technique (PIV) was used to conduct detailed velocity measurements in the upstream parallel section, within the converging and diverging section, and downstream of the converging and diverging sections. From these measurements, the boundary layer parameters and profiles of the mean velocities, turbulent quantities as well as terms in the transport equations for turbulent kinetic energy and Reynolds stresses were obtained to document the effects of pressure gradient on the flow. In the adverse pressure gradient case, the turbulent quantities were enhanced more significantly in the lower boundary layer than the upper boundary layer. On the other hand, favorable pressure gradient attenuated the turbulence levels and the effect was found to be similar on both the upper and the lower boundary layers. For the separated and reattached flows in the converging, diverging and parallel-wall channels at Reh = 19440, 12420 and 15350, respectively. The Reynolds number based on the approach velocity and rib height was Rek  2700. From these measurements, profiles of the mean velocities, turbulent quantities and the various terms in the transport equations for turbulent kinetic energy and Reynolds stresses were also obtained. The flow dynamics in the upper boundary layer in the separated region and the early stages of flow redevelopment were observed to be insensitive to the pressure gradients. In the lower boundary layer, however, the flow dynamics were entirely dominated by the separated shear layer in the separated region as well as the early region of flow redevelopment. The effects of the separated shear layer diminished in the redevelopment region so that the dynamics of the flow were dictated by the pressure gradients. The proper orthogonal decomposition (POD) was applied to educe the dominant large scale structures in the separated and reattached flows. These dominant scales were used to document structural differences between the canonical upstream flow and the flow field within the separated and redeveloping region. The contributions of these dominant structures to the dynamics of the Reynolds normal and shear stresses are also presented and discussed. It was observed that the POD recovers Reynolds shear stress more efficiently than the turbulent kinetic energy. The reconstruction reveals that large scales contribute more to the Reynolds shear stress than the turbulent kinetic energy. / February 2009

An experimental program is designed to study the salient features of separated and reattached flows in pressure gradients generated in asymmetric diverging and converging channels. The channels comprised a straight flat floor and a curved roof that was preceded and followed by straight parallel walls. Reference measurements were also made in a parallel-wall channel to facilitate the interpretation of the pressure gradient flows. A transverse square rib located at the start of convergence/divergence was used to create separation inside the channels. In order to simplify the interpretation of the relatively complex separated and reattached flows in the asymmetric converging and diverging channels, measurements were made in the plain converging and diverging channel without the rib on the channel wall. All the measurements were obtained using a high resolution particle image velocimetry technique. The experiments without the ribs were conducted in the diverging channel at Reynolds number based on half channel depth (Reh) of 27050 and 12450 and in the converging channel at Reh = 19280. For each of these three test conditions, a high resolution particle image velocimetry technique (PIV) was used to conduct detailed velocity measurements in the upstream parallel section, within the converging and diverging section, and downstream of the converging and diverging sections. From these measurements, the boundary layer parameters and profiles of the mean velocities, turbulent quantities as well as terms in the transport equations for turbulent kinetic energy and Reynolds stresses were obtained to document the effects of pressure gradient on the flow. In the adverse pressure gradient case, the turbulent quantities were enhanced more significantly in the lower boundary layer than the upper boundary layer. On the other hand, favorable pressure gradient attenuated the turbulence levels and the effect was found to be similar on both the upper and the lower boundary layers. For the separated and reattached flows in the converging, diverging and parallel-wall channels at Reh = 19440, 12420 and 15350, respectively. The Reynolds number based on the approach velocity and rib height was Rek  2700. From these measurements, profiles of the mean velocities, turbulent quantities and the various terms in the transport equations for turbulent kinetic energy and Reynolds stresses were also obtained. The flow dynamics in the upper boundary layer in the separated region and the early stages of flow redevelopment were observed to be insensitive to the pressure gradients. In the lower boundary layer, however, the flow dynamics were entirely dominated by the separated shear layer in the separated region as well as the early region of flow redevelopment. The effects of the separated shear layer diminished in the redevelopment region so that the dynamics of the flow were dictated by the pressure gradients. The proper orthogonal decomposition (POD) was applied to educe the dominant large scale structures in the separated and reattached flows. These dominant scales were used to document structural differences between the canonical upstream flow and the flow field within the separated and redeveloping region. The contributions of these dominant structures to the dynamics of the Reynolds normal and shear stresses are also presented and discussed. It was observed that the POD recovers Reynolds shear stress more efficiently than the turbulent kinetic energy. The reconstruction reveals that large scales contribute more to the Reynolds shear stress than the turbulent kinetic energy.

An experimental program is designed to study the salient features of separated and reattached flows in pressure gradients generated in asymmetric diverging and converging channels. The channels comprised a straight flat floor and a curved roof that was preceded and followed by straight parallel walls. Reference measurements were also made in a parallel-wall channel to facilitate the interpretation of the pressure gradient flows. A transverse square rib located at the start of convergence/divergence was used to create separation inside the channels. In order to simplify the interpretation of the relatively complex separated and reattached flows in the asymmetric converging and diverging channels, measurements were made in the plain converging and diverging channel without the rib on the channel wall. All the measurements were obtained using a high resolution particle image velocimetry technique. The experiments without the ribs were conducted in the diverging channel at Reynolds number based on half channel depth (Reh) of 27050 and 12450 and in the converging channel at Reh = 19280. For each of these three test conditions, a high resolution particle image velocimetry technique (PIV) was used to conduct detailed velocity measurements in the upstream parallel section, within the converging and diverging section, and downstream of the converging and diverging sections. From these measurements, the boundary layer parameters and profiles of the mean velocities, turbulent quantities as well as terms in the transport equations for turbulent kinetic energy and Reynolds stresses were obtained to document the effects of pressure gradient on the flow. In the adverse pressure gradient case, the turbulent quantities were enhanced more significantly in the lower boundary layer than the upper boundary layer. On the other hand, favorable pressure gradient attenuated the turbulence levels and the effect was found to be similar on both the upper and the lower boundary layers. For the separated and reattached flows in the converging, diverging and parallel-wall channels at Reh = 19440, 12420 and 15350, respectively. The Reynolds number based on the approach velocity and rib height was Rek  2700. From these measurements, profiles of the mean velocities, turbulent quantities and the various terms in the transport equations for turbulent kinetic energy and Reynolds stresses were also obtained. The flow dynamics in the upper boundary layer in the separated region and the early stages of flow redevelopment were observed to be insensitive to the pressure gradients. In the lower boundary layer, however, the flow dynamics were entirely dominated by the separated shear layer in the separated region as well as the early region of flow redevelopment. The effects of the separated shear layer diminished in the redevelopment region so that the dynamics of the flow were dictated by the pressure gradients. The proper orthogonal decomposition (POD) was applied to educe the dominant large scale structures in the separated and reattached flows. These dominant scales were used to document structural differences between the canonical upstream flow and the flow field within the separated and redeveloping region. The contributions of these dominant structures to the dynamics of the Reynolds normal and shear stresses are also presented and discussed. It was observed that the POD recovers Reynolds shear stress more efficiently than the turbulent kinetic energy. The reconstruction reveals that large scales contribute more to the Reynolds shear stress than the turbulent kinetic energy.

Mental health disorders are highest among adults who are separated and divorced, with 23% of men in this group reporting a mental illness. Separated men are more likely to commit suicide compared with married men. In Australia, there are over 53,100 divorces per annum, involving almost 50,000 children. To date, little research has been conducted on the mental health of separated men who are fathers. Aims: Using a pilot qualitative study, parenting and health issues reported by 23 south-east Queensland separated fathers were examined. The pilot study informed the selection of correlates and measurements for the quantitative study. The aims of the subsequent quantitative study of 80 Queensland separated fathers were to examine: (1) how postseparation stressors, conflict with the ex-partner, access to children, and generativity impact on fathers' grief; and (2) how grief impacts on the mental health of separated fathers. Model: Variables correlating with separated fathers' grief and mental health were entered into the health model proposed by Bartholomew, Parcel, and Kok (1995). Generativity (caring for others and providing support for the next generation) was a key construct in this research. Results: Results of grief analyses, as measured by the Separated Fathers Grief Scale, indicated that the more generative a separated father, and the fewer and less intense the stressors in his life, the less his grief. A grieving father's access to his children and his perception of his financial insecurity correlated with alcohol abuse, conflict with his expartner and stressors in his life. Parenting concerns were the predominant factor affecting conflict with the ex-partner and stressors for separated fathers. Results indicate that a generative father with a positive perception of his financial security and few stressors had low levels of depression anxiety and stress, unless he was unable to resolve his grief over separation from his children. Implications for Public Health: For separated fathers, findings that increased generativity serves as a preventive for grief and mental health problems, support the potential benefit of educational programs utilising an adult developmental approach. Social and legislative changes are required to ensure that: fathering is given equal importance to mothering; consensual rather than adversarial legal processes are promoted; and equitable maintenance and financial planning strategies are promoted to increase the financial security of all separated parents and their children.

<p>For internal flows, the detachment of the boundary layer is a major contributor to pressure loss. To improve efficiency, it is essential to characterize these regions to understand the location and magnitude. Particle Image Velocimetry (PIV) is applied to provide time-resolved measurements to achieve accurate results without perturbing the flow. This thesis covers the methodology for creating an adaptable optical measurement technique in a high frequency study of separated regions in transonic internal flows. Focus on the optimization of the laser optical array and image acquisition system yield improved Dynamic Spatial Range (DSR) and Dynamic Velocity Range (DVR). Further analysis is provided on the flow dynamics of the seed particle, with local seeding solutions provided for improved seeding density in high-speed flows for various geometries. Light scattering efficiency of the particle is also analyzed to completely define the desired particle size. Two pulse-burst Nd:YAG lasers and two high speed cameras are used in this study to achieve a frame straddling technique necessary to resolve high frequency flows. Comparison of the recording media to the DSR highlights performance costs and benefits between the two cameras. Uncertainty measurements are determined from the calculated setup and compared to correlation statistics-based uncertainty quantifications. Image processing and cross-correlation software are used to provide analysis on the flow characteristics for two separate studies with comparison to Computational Fluid Dynamic predictions.</p>

The efficacy of USDA approved antimicrobials was evaluated in reducing Salmonella and Campylobacter on ground chicken frames and chicken breast fillets. Chicken frames dip treated with peracetic acid (PAA), lauric arginate (LAE), cetylpyridinium chloride (CPC) and acidified lactic acid (ALA) reduced Salmonella and Campylobacter counts in ground chicken frames without affecting meat pH and color. PAA and LAE reduced Salmonella by 0.9 log on d0 whereas on d1, PAA and CPC reduced by 1.4 and 0.9 log CFU/g respectively. PAA, ALA, propionic acid and LAE significantly reduced Campylobacter by 0.7, 1.0, 1.3, and 1.2 log CFU/g, respectively. On chicken breast fillets, 30 s application of PAA (0.04% and 0.07% pH 6.5) reduced loosely attached Salmonella by 0.5 and 0.8 log CFU/ml, respectively. ALA, octanoic acid and PAA reduced loosely attached Campylobacter by 1 log while all treatments except propionic acid were effective against strongly attached cells on chicken breast fillets.

Computational fluid dynamics (CFD) methods and schemes have been evolving at a rate that significantly outpaces the equipment needed to readily utilize them at scale. This lack of computational resources has resulted in an increased reliance on turbulence models and the need to know where turbulence models do well, where they do poorly, and where/how they can be improved upon. The BeVERLI Hill experiments aim to address this issue by providing experimental data that achieves a completeness level of three, which has never been done for this type of project. The experimental data collected is studied along side computational results from CFD solvers in order to help address and answer these questions. This paper provides an overview of the current computational status of the BeVERLI Hill project at Virginia Tech. The computational grids used for the analyses are presented such that the reader can gain an appreciation for the modeling techniques and methods being implemented. An analysis of the numerical error associated with the computational results is presented to provide confidence in the results obtained. An in-depth analysis will be presented that shows the results for the various grid levels that are being utilized to determine any grid based effects that are occurring within the solutions. Then, an analysis of the influence of the Reynolds numbers being run is shown. An investigation into the differences between the two different solvers being utilized, SENSEI and Fluent, is shown. An analysis of the effects on the solutions due to numerical limiters is presented to assist in increasing the computational efficiency of the workflow while not adversely affecting the results. Finally, an analysis of the differences between the two turbulence models being utilized is presented. Computational results are compared to available experimentally obtained data to further motivate and identify flow features. / Master of Science / An analysis has been done with high-fidelity computational fluid dynamic solvers that are utilized in order to solve for the flow over a three-dimensional bump called BeVERLI. An analysis is provided that discusses the use of different computational meshes, solvers, turbulence models, and numerical limiters within the computational tools to characterize the flow over the bump. An analysis of the estimated amount of numerical error within the solutions is provided along with a comparison to experimentally obtained data.

A clinical study was performed in order to determine if healthy test subjects can differentiate between adjacent and separated pairs of vertebrae in the lumbar spine. The variable of interest was number of correctly specied pairs of vertebrae. The test subjects were evaluated in terms of sensitivity and specicity of this test. Bootstrap resampling was applied in the data analysis. The results clearly indicated that the test subjects in this study were able to successfully determine whether a pair of adjacent or separated vertebrae was tested during the procedure.

Since its introduction in 1999, bounded model checking (BMC) has quickly become a serious and indispensable tool for the formal verification of hardware designs and, more recently, software. By leveraging propositional satisfiability (SAT) solvers, BMC overcomes some of the shortcomings of more conventional model checking methods. In model checking we automatically verify whether a state transition system (STS) describing a design has some property, commonly expressed in linear temporal logic (LTL). BMC is the restriction to only checking the looping and non-looping runs of the system that have bounded descriptions. The conventional BMC approach is to translate the STS runs and LTL formulae into propositional logic and then conjunctive normal form (CNF). This CNF expression is then checked by a SAT solver. In this thesis we study the effect on the performance of BMC of changing the translation to propositional logic. One novelty is to use a normal form for LTL which originates in resolution theorem provers. We introduce the normal form conversion early on in the encoding process and examine the simplifications that it brings to the generation of propositional logic. We further enhance the encoding by specialising the normal form to take advantage of the types of runs peculiar to BMC. We also improve the conversion from propositional logic to CNF. We investigate the behaviour of the new encodings by a series of detailed experimental comparisons using both hand-crafted and industrial benchmarks from a variety of sources. These reveal that the new normal form based encodings can reduce the solving time by a half in most cases, and up to an order of magnitude in some cases, the size of the improvement corresponding to the complexity of the LTL expression. We also compare our method to the popular automata-based methods for model checking and BMC.

M.A. University of the Witwatersrand, Faculty of Humanities (Forced Migration Studies), 2012 / Background: This research investigates the psychosocial needs of cross-border unaccompanied minors (UAMs) within urban Johannesburg, a city that attracts nearly half of all the cross-border migrant population in South Africa (Landau and Gindrey, 2008). The focus of the research is dual; firstly, it explores what the prime psychosocial needs of UAMs are by eliciting them from the UAMs themselves via participatory research workshops. South Africa, by law, has an obligation to all UAMs to provide for them. By ascertaining these needs, this study reveals discrepancies between existing psychosocial programmes designed and provided by the government or service providers and the needs of the UAM. Secondly, the research examines how UAMs are trying to satisfy their psychosocial needs. Identifying the psychosocial needs of UAMs and their coping mechanisms gives us a better understanding of the nature of the issues UAMs face, as well as their subjective perception of and priority they place on those issues. This can consequently contribute (a) to providing constructive suggestions on designing psychosocial programmes by governmental, nongovernmental organisations (NGOs), and non-profit organisations (NPOs) and (b) valuable input to further research on livelihood-seeking UAMs, a group that is currently under-represented in cross-border UAM studies, unlike asylum seeking or refugee UAMs. Aims: The aim of this study is to understand the psychosocial needs of UAMs and how they are meeting those needs in Johannesburg. This will provide insights on the nature of the psychosocial needs of UAMs that will ultimately be helpful both to government agencies as well as NGOs and NPOs responsible for programme planning, legislation, and execution of policies regarding cross-border UAMs. Finally, the study aims to draw attention to livelihood-seeking UAMs and to encourage further research on this particular group of UAMs. Therefore my research question is: what are the psychosocial needs of cross-border UAMs in Johannesburg? Methods: In this study, a qualitative research approach is used with the aim of uncovering the psychosocial needs of cross-border UAMs. This was done by using participatory action research and a visual methodology. The data was elicited via two participatory workshops, the first with 36 cross-border minors participants and the second with 12 cross-border UAM participants. This was followed by a series of group discussions after the workshops. Afterwards, a comparison between the participants’ visual inputs with their narratives and responses allowed me to extrapolate their psychosocial needs and ways in which they meet those needs. Adding to the study, 11 semi-structured interviews were conducted with service providers from various organisations, both non-governmental and governmental. Finally, the data was compiled from both the cross-border UAM s and service providers to answer the research question and objectives. Conclusion: This research identifies and discusses the following psychosocial needs of crossborder UAMs: family, a care-giver, documentation, fitting-in with their South African peers, security, schooling, better life quality (economic and social advancement), counselling, and playing. The four themes in bold text represent psychosocial needs, which continue to be unmet or unfulfilled by service providers current responses. Although the basic (ontological) needs of cross-border UAMs seem to be met (i.e., food, housing, clothing), psychosocial needs - those needed for emotional well-being - are undermined because service providers do not see them as fundamental as basic needs. One conclusion from my study is that NGOs can better cater to UAMs’ psychosocial needs due to their flexible infrastructure that can accommodate personalisation and prompt redesigning of programmes offered, in contradistinction to the recalcitrant governmental infrastructure. Currently service providers, such as governmental departments, NGOs and NPOs use the law (such as the Children’s Act (2008)), regulations or psychosocial programmes to aid cross-border UAMs, but these laws and programmes are manufactured for either homogenous groups or very specific groups such as refugees and asylum seekers. However, there are persisting gaps in the services available. These gaps are due to the varied nature of psychosocial needs that each ‘child’ has to meet, which is also contingent on their own background and personality. Under the Children’s Act (2008), minors are categorised as a homogeneous group and therefore individual needs are overlooked. Organisations both governmental and non-governmental have tried to incorporate child friendly practices, although in most of the interviews it was mentioned that policy, such as the Children’s Act (2008), is not necessarily ‘child’ or ‘family’ friendly. Overall this research indicates that NGOs and NPOs are well-equipped to cater to the psychosocial needs of UAMs, such as school, family reunification and basic needs. Certain psychosocial needs, however, such as ‘fitting-in’, are still unmet. In these cases, UAMs resort to catering to their own needs (lke living on the street in selfappointed families), relying on service providers for emotional support and/or basic needs.