The temperature of the flow entering a high-pressure turbine stage is inherently non-uniform, as it is produced by several discrete, azimuthally-distributed combustors. In general, however, industrial simulations assume inlet temperature uniformity to simplify the preparation process and reduce computation time. The effects of a non-uniform inlet field on the performance of a commercial, transonic, single-stage, high-pressure, axial turbine with a curved inlet duct have been investigated numerically by performing URANS (Unsteady Reynolds-Averaged Navier-Stokes equations) simulations with the SST (Shear Stress Transport) turbulence model. By adjusting the alignment of the experimentally-based inlet temperature field with respect to the stator vanes, two clocking configurations were generated: a vane-impinging (VI) case , in which each hot streak impinged on a vane; and a mid-pitch (MP) case, in which each hot streak passed between two vanes. In the VI configuration, the hot streaks produced higher time-averaged heat load on the vanes and lower heat load on the blades. As the hot streaks in the VI case passed over the stator vanes, they also spread spanwise due to the actions of the casing passage vortices and the radial pressure gradient; this resulted in a stream entering the rotor with relatively low temperature variations. The hot streaks in the MP case were convected undisturbed past the relatively cool vane section. Relatively high time-averaged enthalpy values were found to occur on the pressure side of the blades in the MP configuration. The non-uniformity of the time-averaged enthalpy on the blade surfaces was lower in the VI configuration. The flow exiting the rotor section was much less non-uniform in the VI case, but differences in calculated efficiency were not significant. / Pratt & Whitney Canada, NSERC

The temperature of the flow entering a high-pressure turbine stage is inherently non-uniform, as it is produced by several discrete, azimuthally-distributed combustors. In general, however, industrial simulations assume inlet temperature uniformity to simplify the preparation process and reduce computation time. The effects of a non-uniform inlet field on the performance of a commercial, transonic, single-stage, high-pressure, axial turbine with a curved inlet duct have been investigated numerically by performing URANS (Unsteady Reynolds-Averaged Navier-Stokes equations) simulations with the SST (Shear Stress Transport) turbulence model. By adjusting the alignment of the experimentally-based inlet temperature field with respect to the stator vanes, two clocking configurations were generated: a vane-impinging (VI) case , in which each hot streak impinged on a vane; and a mid-pitch (MP) case, in which each hot streak passed between two vanes. In the VI configuration, the hot streaks produced higher time-averaged heat load on the vanes and lower heat load on the blades. As the hot streaks in the VI case passed over the stator vanes, they also spread spanwise due to the actions of the casing passage vortices and the radial pressure gradient; this resulted in a stream entering the rotor with relatively low temperature variations. The hot streaks in the MP case were convected undisturbed past the relatively cool vane section. Relatively high time-averaged enthalpy values were found to occur on the pressure side of the blades in the MP configuration. The non-uniformity of the time-averaged enthalpy on the blade surfaces was lower in the VI configuration. The flow exiting the rotor section was much less non-uniform in the VI case, but differences in calculated efficiency were not significant. / Pratt & Whitney Canada, NSERC

The temperature of the flow entering a high-pressure turbine stage is inherently non-uniform, as it is produced by several discrete, azimuthally-distributed combustors. In general, however, industrial simulations assume inlet temperature uniformity to simplify the preparation process and reduce computation time. The effects of a non-uniform inlet field on the performance of a commercial, transonic, single-stage, high-pressure, axial turbine with a curved inlet duct have been investigated numerically by performing URANS (Unsteady Reynolds-Averaged Navier-Stokes equations) simulations with the SST (Shear Stress Transport) turbulence model. By adjusting the alignment of the experimentally-based inlet temperature field with respect to the stator vanes, two clocking configurations were generated: a vane-impinging (VI) case , in which each hot streak impinged on a vane; and a mid-pitch (MP) case, in which each hot streak passed between two vanes. In the VI configuration, the hot streaks produced higher time-averaged heat load on the vanes and lower heat load on the blades. As the hot streaks in the VI case passed over the stator vanes, they also spread spanwise due to the actions of the casing passage vortices and the radial pressure gradient; this resulted in a stream entering the rotor with relatively low temperature variations. The hot streaks in the MP case were convected undisturbed past the relatively cool vane section. Relatively high time-averaged enthalpy values were found to occur on the pressure side of the blades in the MP configuration. The non-uniformity of the time-averaged enthalpy on the blade surfaces was lower in the VI configuration. The flow exiting the rotor section was much less non-uniform in the VI case, but differences in calculated efficiency were not significant. / Pratt & Whitney Canada, NSERC

The temperature of the flow entering a high-pressure turbine stage is inherently non-uniform, as it is produced by several discrete, azimuthally-distributed combustors. In general, however, industrial simulations assume inlet temperature uniformity to simplify the preparation process and reduce computation time. The effects of a non-uniform inlet field on the performance of a commercial, transonic, single-stage, high-pressure, axial turbine with a curved inlet duct have been investigated numerically by performing URANS (Unsteady Reynolds-Averaged Navier-Stokes equations) simulations with the SST (Shear Stress Transport) turbulence model. By adjusting the alignment of the experimentally-based inlet temperature field with respect to the stator vanes, two clocking configurations were generated: a vane-impinging (VI) case , in which each hot streak impinged on a vane; and a mid-pitch (MP) case, in which each hot streak passed between two vanes. In the VI configuration, the hot streaks produced higher time-averaged heat load on the vanes and lower heat load on the blades. As the hot streaks in the VI case passed over the stator vanes, they also spread spanwise due to the actions of the casing passage vortices and the radial pressure gradient; this resulted in a stream entering the rotor with relatively low temperature variations. The hot streaks in the MP case were convected undisturbed past the relatively cool vane section. Relatively high time-averaged enthalpy values were found to occur on the pressure side of the blades in the MP configuration. The non-uniformity of the time-averaged enthalpy on the blade surfaces was lower in the VI configuration. The flow exiting the rotor section was much less non-uniform in the VI case, but differences in calculated efficiency were not significant. / Pratt & Whitney Canada, NSERC

>Magister Scientiae - MSc / Maize streak disease (MSD), caused by variants of the Maize streak virus (MSV) A strain, is the world's third and Africa’s most important maize foliar disease. Outbreaks of the disease occur frequently and in an erratic fashion across Africa and Islands in the Indian Ocean causing devastating yield losses such that the emergence, resurgence and rapid diffusion of MSV-A variants in this region presents a serious threat to maize production, farmer livelihoods and food security. To compliment current MSD management systems, a total of 689 MSV-A full genomes sampled over a 32 year period (1979-2011) from 20 countries across Africa and the adjacent Indian Ocean Islands, 286 of which were novel, were used to estimate: (i) the levels of genetic diversity using MEGA and the Sequence Demarcation Tool v1.2 (SDT); (ii) the times of occurrence and distribution of recombination using the recombination detection program (RDP v.4) and the genetic algorithm for recombination detection (GARD); (iii) selection pressure on codon positions using PARRIS and FUBAR methods implemented on the DATAMONKEY web server; (iv) reconstruct the history of spatio-temporal diffusion for MSV-A using the discrete phylogeographic models implemented in BEAST v1.8.1; (v) characterize source-sink dynamics and identify predictor variables driving MSV-A dispersal using the generalized linear models, again implemented in BEAST v1.8.1. Isolates used displayed low levels of genetic diversity (0.017 mean pairwise distance and ≥ 98% nucleotide sequence identities), and a well-structured geographical distribution where all of the 233 novel isolates clustered together with the -A1 strains. A total of 34 MSV inter-strain recombination events and 33 MSV-A intra-strain recombination events, 15 of which have not been reported in previous analyses (Owor et al., 2007, Varsani et al., 2008 and Monjane et al., 2011), were detected. The majority of intra-strain MSV-A recombination events detected were inferred to have occurred within the last six decades, the oldest and most conserved of these being events 19, 26 and 28 whereas the most recent events were 8, 16, 17, 21, 23, and 29. Intra-strain recombination events 20, 25 and 33, were widely distributed amongst East African MSV-A samples, whereas events 16, 21 and 23, occurred more frequently within West African MSV-A samples. Events 1, 4, 8, 10, 14, 17, 19, 22, 24, 25, 26, 28, and 29 were more widely distributed across East, West and Southern Africa and the adjacent Indian Ocean Islands. Whereas codon positions 12 and 19 within motif I in the coat protein transcript, and four out of the seven codon positions (147, 166, 195, 203, 242, 262, 267) in the Rep transcript (codons 195 and 203 in the Rb motif and codons 262 and 267 in site B of motif IV), evolved under strong positive selection pressure, those in the movement protein (MP) and RepA protein encoding genes evolved neutrally and under negative selection pressure respectively. Phylogeographic analyses revealed that MSV-A first emerged in Zimbabwe around 1938 (95% HPD 1904 - 1956), and its dispersal across Africa and the adjacent Indian Ocean Islands was achieved through approximately 34 migration events, 19 of which were statistically supported using Bayes factor (BF) tests. The higher than previously reported mean nucleotide substitution rate [9.922 × 10-4 (95% HPD 8.54 × 10-4 to 1.1317 × 10-3) substitutions per site per year)] for the full genome recombination-free MSV-A dataset H estimated was possibly a result of high nucleotide substitution rates being conserved among geminiviruses such as MSV as previously suggested. Persistence of MSV-A was highest in source locations that include Zimbabwe, followed by South Africa, Uganda, and Kenya. These locations were characterized by high average annual precipitation; moderately high average annual temperatures; high seasonal changes; high maize yield; high prevalence of undernourishment; low trade imports and exports; high GDP per capita; low vector control pesticide usage; high percentage forest land area; low percentage arable land; high population densities, and were in close proximity to sink locations. Dispersal of MSV-A was frequent between locations that received high average annual rainfall, had high percentage forest land area, occupied high latitudes and experienced similar climatic seasons, had high GDP per capita and had balanced maize import to export ratios, and were in close geographical proximity. / National Research Foundation (NRF), the Poliomyelitis Research Foundation (PRF), and the Thuthuka Board

Indiana University-Purdue University Indianapolis (IUPUI) / Statistics and athletic sports have always had a strong connection that many critics, fans and statisticians utilize to determine how successful a team or an individual player might be over an entire season or even throughout one’s career. The success of a player or team is often characterized by investigating the consistency that has been shown throughout the season or career, which has led to more investigation of the streakiness of players. Studies have been done to examine great streaks, such as Joe DiMaggio’s 56 game hitting streak or Tiger Woods’ 142 consecutive cuts made streak, but what about the outstanding streak that occurred during the 1983-1984 NHL season? Wayne Gretzky, of the Edmonton Oilers, managed to showcase just how elite he was as a playmaker during that season. Gretzky produced a remarkable 51-game point streak, in which he recorded at least one goal or point in 51 consecutive games; a streak that has not received the recognition that it deserves. Using game-by-game data for the entire 1983-1984 NHL season for all players, the research looks at not only the evaluation of Gretzky’s streak, but also compares his production and streak to the remainder of the league. Gretzky demonstrated why he is one of the greatest players to ever step foot on the ice, and his elite status is shown throughout this analysis. Comparing Gretzky’s streak to that of DiMaggio’s was shown to be a little challenging but, some general conclusions were made based on the comparison of analyses that were performed; but without the proper statistics being readily available, it is hard to adequately dictate which streak is ultimately more impressive or more rare.

Call number: LD2668 .T4 1955 K35 / Master of Science

No description available.

Thesis (M.S. in plant pathology)--Washington State University, December 2006. / Includes bibliographical references (p. 68-76).

Call number: LD2668 .T4 1986 S76 / Master of Science / Plant Pathology