1,033 research outputs found
Champions, Memphis Interscholastic Conference
No full textOne of Brother Sylvester's championship teams of the 1920s, the Christian Brothers College baseball team won the Memphis Interscholastic Conference in 1924.
Top row (L-R): R. Benedetto, J. Kuhn, Brother Sylvester, A. Sharp, E. Reilly. Middle Row: W. Fay, H. Bugg , R. Ward, E. Kennedy, J. Caselli, W. Carruthers, E. Kuhn.
Bottom Row: M. Hale, S. Schneider, C. Tate, T. Manigan, J. MacDowell
Assembly in vitro of rhodococcus jostii RHA1 encapsulin and peroxidase DypB to form a nano-compartment
No full textRhodococcus jostii RHA1 peroxidase DypB has been recently identified as a bacterial lignin peroxidase. The dypB gene is co-transcribed with a gene encoding an encapsulin protein, shown in Thermotoga maritima to assemble to form a 60-subunit nano-compartment, and DypB contains a C-terminal sequence motif thought to target the protein to the encapsulin nanocompartment. R. jostii RHA1 encapsulin protein has been overexpressed in R. jostii RHA1, and purified as a high molecular weight assembly (Mr >106). The purified nanocompartment can be denatured to form a low molecular weight species by treatment at pH 3.0, and can be re-assembled to form the nanocompartment at pH 7.0. Recombinant DypB can be assembled in vitro with monomeric encapsulin to form an assembly of similar size and shape to the encapsulin-only nanocompartment, assessed by dynamic light scattering. The assembled complex shows enhanced lignin degradation activity per mg DypB present, compared with native DypB, using a nitrated lignin UV-vis assay method. The measured stoichiometry of 8.6 µmoles encapsulin/µmol DypB in the complex is comparable to the value of 10 predicted from the crystal structure
Plasma position control in the STOR-M tokamak : a fuzzy logic approach
No full textAdequate control of the position of the plasma column within the STOR-M tokamak is a chief requirement in order for experimental quality discharges to be obtained. Optimal control over tokamak discharge parameters, including the plasma position, is very difficult to achieve. This is due in large part to the difficulty in modelling the tokamak discharge parameters, as they are highly nonlinear and time varying in nature. The difficulty of modelling the tokamak discharge parameters suggests that a control system, such as a fuzzy logic based controller, which does not require a system model may be well suited to the control of fusion plasma.
In order to improve the quality of control over the plasma position within the STOR-M tokamak, the existing analog PID controller was modified. These modifications facilitate the application of a digital controller by a personal computer via the Advantech PCL-711B data acquisition card. The performance of the modified plasma position controller and an Arbitrary Signal Generator developed by the author was evaluated. This modified plasma position controller was applied successfully to the STOR-M tokamak during both normal mode and A.C. mode operation. In both cases, the modified controller provided adequate control over the position of the plasma column within the discharge chamber. Furthermore, the modified controller was more convenient to optimize than the original, existing analog PID controller.
By taking advantage of the modifications that were made to the plasma position controller, a fuzzy logic controller was developed by the author. The fuzzy logic based plasma position controller was also successfully applied to the STOR-M tokamak during both normal mode and A.C. operation. The fuzzy controller was demonstrated to reliably provide a higher degree of control over the position of the plasma column within the STOR-M tokamak than the modified PID controller
Evidence for the decay B0→J/ψω and measurement of the relative branching fractions of meson decays to J/ψη and J/ψη′
No full textFirst evidence of the B 0 → J / ψ ω decay is found and the B s 0 → J / ψ η and B s 0 → J / ψ η ′ decays are studied using a dataset corresponding to an integrated luminosity of 1.0 fb -1 collected by the LHCb experiment in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV. The branching fractions of these decays are measured relative to that of the B 0 → J / ψ ρ 0 decay:frac(B (B 0 → J / ψ ω), B (B 0 → J / ψ ρ 0)) = 0.89 ± 0.19 (stat) - 0.13 + 0.07 (syst),frac(B (B s 0 → J / ψ η), B (B 0 → J / ψ ρ 0)) = 14.0 ± 1.2 (stat) - 1.5 + 1.1 (syst) - 1.0 + 1.1 (frac(f d, f s)),frac(B (B s 0 → J / ψ η ′), B (B 0 → J / ψ ρ 0)) = 12.7 ± 1.1 (stat) - 1.3 + 0.5 (syst) - 0.9 + 1.0 (frac(f d, f s)), where the last uncertainty is due to the knowledge of f d / f s, the ratio of b-quark hadronization factors that accounts for the different production rate of B 0 and B s 0 mesons. The ratio of the branching fractions of B s 0 → J / ψ η ′ and B s 0 → J / ψ η decays is measured to befrac(B (B s 0 → J / ψ η ′), B (B s 0 → J / ψ η)) = 0.90 ± 0.09 (stat) - 0.02 + 0.06 (syst)
Manual and semi-automated delineation of locally advanced rectal cancer subvolumes with diffusion-weighted MRI
No full textOBJECTIVES: To evaluate interobserver agreement for T2 weighted (T2W) and diffusion-weighted MRI (DW-MRI) contours of locally advanced rectal cancer (LARC); and to evaluate manual and semi-automated delineations of restricted diffusion tumour subvolumes. METHODS: 20 cases of LARC were reviewed by 2 radiation oncologists and 2 radiologists. Contours of gross tumour volume (GTV) on T2W, DW-MRI and co-registered T2W/DW-MRI were independently delineated and compared using Dice Similarity Coefficient (DSC), mean distance to agreement (MDA) and other metrics of interobserver agreement. Restricted diffusion subvolumes within GTVs were manually delineated and compared to semi-automatically generated contours corresponding to intratumoral apparent diffusion coefficient (ADC) centile values. RESULTS: Observers were able to delineate subvolumes of restricted diffusion with moderate agreement (DSC 0.666, MDA 1.92 mm). Semi-automated segmentation based on the 40th centile intratumoral ADC value demonstrated moderate average agreement with consensus delineations (DSC 0.581, MDA 2.44 mm), with errors noted in image registration and luminal variation between acquisitions. A small validation set of four cases with optimised planning MRI demonstrated improvement (DSC 0.669, MDA 1.91 mm). CONCLUSION: Contours based on co-registered T2W and DW-MRI could be used for delineation of biologically relevant tumour subvolumes. Semi-automated delineation based on patient-specific intratumoral ADC thresholds may standardise subvolume delineation if registration between acquisitions is sufficiently accurate. ADVANCES IN KNOWLEDGE: This is the first study to evaluate the feasibility of semi-automated diffusion-based subvolume delineation in LARC. This approach could be applied to dose escalation or 'dose painting' protocols to improve delineation reproducibility.Full Tex
Population-specific transcriptional plasticity and sub-lethal thermal thresholds in developing lake sturgeon, Acipenser fulvescens
No full textChanging temperatures elevate threats to physiological function in endangered freshwater species such as the lake sturgeon, Acipenser fulvescens, especially throughout vulnerable periods of early development. If temperatures breach sub-lethal thresholds, transcriptomic plasticity and acclimation capacity and a reduction of protein level responses may be diminished, increasing the vulnerability of lake sturgeon to additional environmental stressors. My thesis research investigated the effects of changing temperatures on the physiology of developing lake sturgeon from Manitoba, Canada. A common garden strategy was employed, where lake sturgeon from northern and southern populations within Manitoba were reared at equivalent and environmentally-relevant temperatures. Lake sturgeon demonstrated acclimation-specific effects on thermal tolerance related phenotypes including morphology, metabolic rate, critical thermal maximum, transcriptional responses, mortality and transcriptional responses to cold stress later in life with relative performance in many traits declining as acclimatory temperatures increased. Many of the above phenotypic responses were population-specific, with lower thermal maxima and sub-lethal thermal thresholds in the northern population of lake sturgeon. Next, I used mRNA sequencing of gill tissue and found enhanced transcriptional plasticity in the southern population relative to the less thermally tolerant northern counterparts. Pathway-specific functional analysis implicated mitochondrial function, oxidative damage, and immunocompetence as key mechanisms modulated by increasing acclimation temperatures with functional analysis indicating additional population-specific biological processes. Last, we specifically investigated the effects of sub-lethal thermal thresholds on stress and innate immune capacity through transcriptional profiling using qPCR. Acclimation temperature influenced the endocrine stress response and impaired the activation of molecular pathways involved in the immune, stress, and fatty acid responses of pathogen-challenged lake sturgeon in early development. Collective results suggest that, as environmental temperatures intensify, transcriptional plasticity, sub-lethal thermal tolerance thresholds, and overall physiological plasticity are diminished, likely resulting in the increased susceptibility of developing lake sturgeon to the effects of compounding environmental stressors.Funding for these studies was additionally provided by NSERC/Manitoba Hydro Industrial Research Chair awarded to W.G.A. and NSERC Discovery Grants (grant numbers 05348 and 05479) awarded to W.G.A. and K.M.J., respectivelyFebruary 202
Measurement of the polar-angle distribution of leptons from W boson decay as a function of the W transverse momentum in p(p)over-bar collisions ar root s=1.8 TeV
No full textWe present a measurement of the polar-angle distribution of leptons from W boson decay, as a function of the W transverse momentum. The measurement uses an 80+/-4 pb(-1) sample of p (p) over bar collisions at roots=1.8 TeV collected by the CDF detector and includes data from both the W--\u3ee+nu and W--\u3emu+nu decay channels. We fit the W boson transverse mass distribution to a set of templates from a Monte Carlo event generator and detector simulation in several ranges of the W transverse momentum. The measurement agrees with the standard model expectation, whereby the ratio of longitudinally to transversely polarized W bosons, in the Collins-Soper W rest frame, increases with the W transverse momentum at a rate of approximately 15% per 10 GeV/c
MODELING TURBULENT GAS-LIQUID BUBBLY FLOW IN A VERTICAL PIPE
No full textBubbly gas-liquid turbulent flow occurs in various industrial applications, for example oil and gas production, petrochemical plants, nuclear reactors, etc. The analysis of bubbly gas-liquid turbulent flow remains a challenging task due to complexities such as the dispersed gas phase effects on the continuous liquid phase turbulence, interphase momentum exchange, and redistribution of the gas volume fraction due to bubble coalescence and breakup. The focus of this thesis is to develop a computational model to address these challenges. The model developed in this thesis uses a state-of-the-art two-fluid method, which minimizes computational resources and is based on the Reynolds-Averaged Navier-Stokes (RANS) equations. The predictions obtained for bubbly upward flow in a vertical pipe were validated against the available experimental data.
The first part of this thesis, chapter 2, documents a one-dimensional Eulerian-Eulerian two-fluid model for mono-disperse bubbly gas-liquid flow. The main challenge is the prediction of the gas volume fraction profile, based on the radial force balance of the non-drag forces for the gas phase. The shape of the volume fraction profile across the pipe changes depending on the bubble size. The volume fraction profile exhibits a peak value near the wall and at the centre line of the pipe for smaller and larger bubbles, respectively, which is consistent with experimental measurements. For the model tested, the turbulence kinetic energy was observed to increase for larger size bubbles compared to the smaller size bubbles.
The second part of the thesis, chapter 3, reports a thorough investigation of the effect of bubbles on the liquid phase turbulence, referred to as turbulence modulation. The presence of bubbles in the flow can either enhance or attenuate the liquid phase turbulence. For the same flow conditions, the effect of the turbulence modulation shows both enhancement and suppression for the turbulence kinetic energy in different locations in the pipe. A budget analysis of the turbulence transport equations was used to provide insight on the relative importance of the turbulence modulation and to identify the region where it plays a significant role. The turbulence modulation was often found to have an insignificant effect on the prediction for the mean flow variables.
The third part of the thesis, chapter 4, describes a numerical study of poly-disperse gas-liquid flow, which contains bubbles of different diameter. For a poly-disperse distribution of gas bubbles, the model must account for the consequences of bubbles either breaking up or coalescing with each other. To explore their effect, an inhomogeneous multiple size group (iMUSIG) approach with a bubble coalescence and breakup model was implemented. The developed model was shown to correctly redistribute the gas volume fraction among the bubble groups based on the coalescence and breakup processes. The turbulence modulation for the poly-disperse flow was found to be larger than for the mono-disperse case, which indicates one additional effect of a poly-disperse distribution of gas bubbles.
Overall, this thesis research implemented a two-fluid model that is able to capture important features of bubbly gas-liquid flow for both mono-disperse and poly-disperse cases. Some significant features of the model are: the use of a radial force balance for the gas volume fraction evaluation; a turbulence modulation contribution based on source terms in the turbulence transport equations; and incorporating the effect of coalescence and breakup processes and the resultant exchange of gas volume fraction among different bubble groups. As such, the thesis documents an improved predictive model for RANS simulations of bubbly gas-liquid flow in industrial applications
Modeling a run-around heat and moisture exchanger using two counter/cross flow exchangers
No full textIn this study, a numerical model is developed for determining coupled heat and moisture transfer in a run-around membrane energy exchanger (RAMEE) using two counter/cross flow exchangers and with a salt solution of MgCl2 as the coupling fluid. The counter/cross flow exchanger is a counter-flow exchanger with cross-flow inlet and outlet headers. The model is two-dimensional, steady-state and based on the physical principles of conservation of momentum, energy, and mass. The finite difference method is used in this model to discretize the governing equations.
The heat transfer model is validated with effectiveness correlations in the literature. It is shown that the difference between the numerical model and correlations is less than ¡À2% and ¡À2.5% for heat exchangers and run around heat exchangers (RAHE), respectively. The simultaneous heat and moisture transfer model is validated with data from another model and experiments. The inter-model comparison shows a difference of less than 1%. The experimental validation shows an average discrepancy of 1% to 17% between the experimental and numerical data for overall total effectiveness. At lower NTUs the numerical and experimental results show better agreement (e.g. within 1-4% at NTU=4).
The model for RAHE is used to develop new effectiveness correlations for the geometrically more complex counter/cross flow heat exchangers and RAHE systems. The correlations are developed to predict the response of the exchangers and overall system to the change of different design characteristics as it is determined by the model. Discrepancies between the simulated and correlated results are within ¡À2% for both the heat exchangers and the RAHE systems.
It is revealed by the model that the overall effectiveness of the counter/cross flow RAMEE depends on the entrance ratio (the ratio of the length of the inlet and outlet headers to the length of the exchanger, xi/x0), aspect ratio (the ratio of the height to the length of the exchanger, y0/x0), number of heat transfer units (NTU), heat capacity rate ratio (Cr*), number of mass transfer units (NTUm), and the mass flow rate ratio of pure salt in desiccant solution to dry air (m*). Beside these dimensionless parameters, the performance of the RAMEE system is affected by the liquid-air flow configuration and the operating inlet temperature and humidity.
This study concludes that the maximum effectiveness of the RAMEE system with two counter/cross flow exchangers occurs when NTU and NTUm are large (e.g. greater than 10). At any NTU, the overall effectiveness of the RAMEE system increases with Cr* until it reaches a maximum value when Cr*= . Increasing Cr* above causes the overall effectiveness to decrease slightly. Therefore, to achieve the maximum overall effectiveness of the system, Cr* must be close to . is a function of NTU and operating conditions e.g., with NTU=10, and under AHRI summer and winter operating conditions, respectively. The exchangers in the RAMEE system are needed to have a small aspect ratio (e.g. y0/x
Low-speed tests of an all-flexible parawing for landing a lifting-body spacecraft
No full textWind tunnel and flight tests to determine aerodynamic characteristics and rigging control of flexible parawing for lifting body spacecraf
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