<p>p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.5px Times}</p> <p>Pulsed Arc Electrohydraulic Discharge (PAED) is a direct plasma water treatmenttechnology that can generate physical and chemical reactions in a single unit process to treat a broad range of chemical and biological contaminants. Karpel Vel Leitner et al. (2005) demonstrated that PAED is capable of treating contaminants via the reduction</p> <p>mechanism, as they reduced nitrate to nitrite. Perchlorate is a difficult-to-treat contaminant with significant negative impacts on human health. One treatment approach for perchlorate is to reduce it. Therefore, laboratory experiments were designed and conducted to examine the efficacy of PAED for reduction of perchlorate in a water matrix.</p> <p>A 3L stainless steel cylindrical reactor with two titanium electrodes connected to a 0.3 kJ/pulse pulsed arc power supply was used for the treatment processes. Three sets of factorial experiments were performed to determine: a) the power supply settings and water matrix properities for optimal ozone and hydrogen peroxide production; b) the efficacy of PAED for the reduction of perchlorate; and c) the power supply settings and water matrix properties for optimal perchlorate reduction.</p> <p>The results of these experiments indicated that as much as 0.0544 mg/L of ozone was generated, with water conductivity and the presence of dissolved oxygen being the most important factors contributing to ozone generation. Hydrogen peroxide was not generated in detectable amounts under any of the conditions employed in these experiments. Finally, perchlorate was not reduced by detectable concentration in any of the conditions employed in these experiments.</p> / Master of Applied Science (MASc)

<p>The goal of seismic response modification is to elicit more favourable behaviour from structures during earthquakes. A popular means for this modification is through the use of energy dissipation devices (EDDs), which effectively lower the seismic demand on main structural components by absorbing a portion of the seismic input energy. This energy is often absorbed through the yielding of metallic components within these devices. Examples of traditionally used metals are steel and lead which exhibit bilinear hysteretic behaviour. The introduction of shape memory alloys (SMAs) into the realm of seismic energy dissipation has occurred fairly recently and has occurred in large part due to their exceptional characteristics for earthquake engineering applications, including hysteretic properties. SMAs exhibit flag-shaped hysteretic behaviour creating the potential for relatively simple yet effective EDDs.</p> <p>In this study, the non-linear time history analysis of 1, 2, 4, and 8 storey chevron-braced steel frame models was carried out using the program Ruaumoko^®. The braces in each frame were modelled to emulate EDDs exhibiting flag-shaped hysteresis. For comparison, the same frames were analyzed with braces modelled to emulate EDDs exhibiting bilinear behaviour with full hysteresis loops. Each frame was subjected to an ensemble of ground motions to determine their mean responses as measured by several response indices. A parametric approach was adopted to determine the effect of various parameters on response and the parameter values resulting in advantageous behaviour. Tension-compression (T-C) and tension-only (T-O) braces were studied to illustrate their effect on response as well. Pushover tests on the frames were also performed, using the program SAP2000^®, to help validate the results.</p> <p>The behaviour of the frames in this study was generally governed by the backbone curve of the brace hystereses defined by post-yielding stiffness parameter, α, normalized yield force, η, and normalized stiffness, θ. Increasing these parameters generally decreased interstorey drift, residual interstorey drift, column ductility demand, beam ductility demand, and absorbed energy. However, this also had the effect of increasing acceleration and base shear. The energy dissipation parameter, β, had little effect on response. In general, the responses of the frames with flag-shaped hysteretic braces, as measured by interstorey drift, column ductility demand, beam ductility demand, base shear, and absorbed energy, were very similar to those frames with the bilinear hysteretic braces - in both magnitude and trend. However, the frames with bilinear braces tended to have lower accelerations, and the frames with flag-shaped braces tended to have lower residual drifts. The T-C braces were generally more effective than the T-O braces in enhancing seismic performance. However, the frames with T-O braces had a resultant lower lateral stiffness - suggesting that T-O braces of sufficient stiffness could be used to garner similar responses offered by T-C braces.</p> / Master of Applied Science (MASc)

<p>Southern Ontario residents are faced with many challenging decisions when growing their own food. The intention of my research is to help these urban residents plan their garden plot in order to yield food for their own use. The form of this research will be a thesis incorporating a decision support system (DSS). This DSS is intended to take in and determine relevant site characteristics (latitude, sun/shade conditions) and use this information to help the user choose a variety of vegetables and herbs. Users will have the option of making a simplified model of their property and nearby structures for shade analysis, and with the results select an appropriate area(s) of their land. This DSS will give the user the freedom to pick vegetables based on conditions and preferences and give graphical and tabular output of the garden layout and details.</p> <p>The objectives of this thesis is to present the why, what, who, where, and how of going beyond local food production for urban consumption to urban citizens growing their own food for themselves. This food can be consumed but also used as a currency with which to barter for other yard produce from neighbours or community members. One could imagine having a bartering relationship with a neighbour or having a weekly or monthly food market to facilitate bartering. This DSS is intended to be one of the building blocks of a food network DSS, which would be used to increase the efficiency of sharing food produced in urban residential gardens (that have been planned using the following DSS prototype).</p> / Master of Applied Science (MASc)

<p>To obtain a better understanding of groundwater contamination, experiments of biocolloid and colloid transport in single, saturated fractures are conducted to have research in contaminants transport in fractured media. Hydraulic tests and solute tracer tests were conducted to characterize fractures. Due to the relatively large volume in the recirculation system, a back-calculation is employed in the analysis of tracer tests.</p> <p>E. coli RS-2GFP tracer tests were conducted on three fractures at specific discharges of 0.1, 1 and 10 cm/min. With higher specific discharges, the percent recovery is higher in F2 and F3, as well as the colloid experiments, which is likely due to higher specific discharges providing biocolloids less opportunity to attach to the fracture walls. But this did not occur in F1, which is likely due to the smaller aperture size.</p> <p>Comparing the synthetic replicas with real fractures in similar specific discharges, recovery of biocolloid was smaller than colloid. In colloid tracer tests, higher recovery appeared in the fractures with larger aperture field, but this is not clearly seen in biocolloid tracer tests. These indicate that the biological properties of bacteria, and the difference of fracture region and the tortuosity influence the transport.</p> / Master of Applied Science (MASc)

<p>Multilayer elastomeric bearings are a type of seismic isolation device that mitigates seismic damage by lengthening the fundamental period of a low-rise structure. Carbon fiber reinforced elastomeric isolators (FREIs) have been identified as a cost effective alternative to bearings reinforced with steel shims. The stable unbonded fiber reinforced elastomeric isolator (SU-FREI) is an evolution of the FREI. In an attempt to reduce costs even further, FREI bearings of a specific aspect ratio and shape factor have been investigated in an unbonded application with successful results. SU-FREI bearings have shown potential as a viable solution for a more affordable and efficient method of seismic base isolation. Several experimental test procedures were employed in this thesis to further investigate the performance of SU-FREI bearings.</p> <p>The first objective of this research was to compare the dynamic properties of unscragged SU-FREI bearings at parallel and diagonal orientations. Square 1/4 scale SU-FREI bearings were subjected to cyclic excitation under design axial load at 0° (parallel) and 45° (diagonal) orientations. Square SU-FREI bearings achieved acceptable base isolation characteristics at both orientations despite subtle differences in their mechanical properties. Stable rollover (SR) deformation was observed for both orientations.</p> <p>The stability of SU-FREI bearings under dynamic excitation was the next topic investigated in this thesis. To achieve this, 1/4 scale square SU-FREI bearings were subjected to cyclic testing under incrementally increasing lateral displacement amplitudes and axial loads. It was found that the critical buckling load under dynamic excitation decreases with increasing lateral excitation amplitude. SU-FREI bearings exhibited acceptable performance at axial loads well in excess of expected design axial loads.</p> <p>In addition, an ultimate shear properties test was performed in order to investigate rollout instability in SU-FREI bearings. Rollout was not observed in bearings tested in this study. Test results did however highlight the stiffening effect of vertical facial contact throughout roll over deformation.</p> <p>Finally, SU-FREI bearings underwent cyclic testing under serviceability and fatigue conditions. Serviceability tests were performed on 1/4 scale SU-FREI bearings at lateral displacement amplitudes corresponding to those expected from a 1 in 10 year return period wind pressure. Fatigue testing was performed on 1/4 scale bearings at a lateral displacement amplitude equal to the total design displacement (D_TD) as required by ASCE 7-05. SU-FREI bearings displayed adequate scragged performance under both serviceability and fatigue testing. Both effective stiffness and damping remained within acceptable limits throughout these tests.</p> / Master of Applied Science (MASc)

<p>The purpose of this thesis is to set up simple computational models which require limited climatical data as input, in order to provide estimates of runoff during the spring-summer melt season for drainage basins in the Baffin Region. Due to the limitation of meteorological data in Arctic areas, the models were developed with only the major components of the hydrologic cycle, the components chosen on logical, physical basis with the restriction that the number of parameters be kept to a minimum.</p> <p>The models were used to generate daily average flows for the Duval River drainage basin. Unlike southern areas the major contribution of precipitation is snow which is retained until the ablation season which lasts from one to four months in Arctic areas. Observed and simulated results were found to be in agreement in terms of both volume and time distribution.</p> <p>As the optimised parameters are kept to a minimum it is hoped that it can be expanded for use on ungauged basins.</p> / Master of Engineering (ME)

<p>Steel structures are commonly used all over the world. Structural cold-formed steel sections can be used as the primary building members, as well as the secondary members with other structural materials. They can be used as joists, truss members, and studs; they can also be used as frame systems, floor systems and wall systems, etc.</p> <p>It is common to see openings in these plated structures for all kinds of reasons. For example, openings are needed for ancillary systems such as water pipes, plumbing, electric wiring, etc. In cold-formed steel members, openings are often introduced in the web of a joist. The existence of large openings can change the stress distribution around the opening regions, thus changing the buckling and strength characteristics of web panels. The extent to which the openings can affect the plated structures depends on the size, shape, locations and number of the openings in the web. In this study, parametric studies were performed on a total of 42 simply supported plates with centrally located square openings utilizing the finite element modeling. The parameters of interest are the size of the opening (d。/h), the slenderness ratio of the plate (h/t) and the aspect ratio of the plate (a/h). It was observed from the study that, a centrally located square opening can significantly reduce the ultimate shear strength of the plate. The opening size is the primary parameter influencing a plate's ultimate shear strength. The ultimate shear strength of a plate decreases approximately linearly as the size of the opening increases. The ultimate shear strength also decreases as the slenderness of the plate increases and tends to increase as the aspect ratio increases. The aspect ratio is found to be the least significant parameter in the sense of affecting the ultimate shear strength of plates with square openings. This study also compared the ultimate shear strength obtained from finite element modeling with that calculated from the AISI (2007) method. It was shown that the AISI (2007) tends to underestimate the ultimate shear strength of thick to moderate thick plates with square openings, but overestimate the ultimate shear strength of thin plates with square openings. A new equation for estimating the shear reduction factor (q_s) is proposed based on the finite element analysis undertaken to better estimate the ultimate shear strength of plates with centralized square openings.</p> <p>To compensate for the reduction in strength of steel members due to large openings, reinforcements may be used in practice. In this research, simply supported steel plates with an aspect ratio of 3 (a/h=3) and having a 60% reinforced square opening (d_c/h =0.6) under pure shear loads were analyzed through the finite element modeling. Four slenderness ratios (h/t), namely h/t=50, 100, 150 and 200 were considered. Three reinforcement schemes, namely the flat-reinforcement, the lip-reinforcement and the angle-reinforcement, are applied on the plates to evaluate the effectiveness of these three reinforcement schemes. It was observed from the research that all three reinforcement schemes were capable of restoring the shear strength of plates with square openings. However, the flat-reinforcement is found to be the most efficient way of the three reinforcement schemes considered.</p> / Master of Applied Science (MASc)

<p>This report describes an experimental investigation into the potential use of return flow from rectangular harbour resonators incorporated into semi-infinite harbour entrances. The mechanism studied includes: the bandwidth of the reduced energy spectrum transmitted into a harbour, the concomitant reflected wave spectra and the energy available for return flow. This report is intended to provide data for the design of on-channel harbour resonators so as to eliminate or reduce the transmission of a selected band of harmful wave frequencies and to maximize the energy of scouring currents so as to prevent the influx and deposition of littoral sediments in harbour entrances. Observations were also made of the potential danger to small vessels provided by the movement of waves into and out of the resonators. The vessels would probably be ejected from the resonator without risk of battering, although the motion locally in the mouth of the resonator will be amplified.</p> / Master of Engineering (ME)

<p>This work presents the results of a pilot plant study where a completely submerged rotating biological contactor was used for denitrification of domestic wastewater.</p> <p>The literature review emphasizes the existing knowledge on RBC operation and design fundamentals. A brief summary of the theory of denitrification has been presented as this subject already has been presented in detail by various authors.</p> <p>Dye studies were performed for 4 stage series operation and single stage operation. A two CSTR with interchange flow model seemed to fit the hydraulic model for single stage operation. The dye responses was observed to be function of biological growth which in turn varied with temperature.</p> <p>"Zero order" kinetics were shown to represent the data obtained for denitrification rates at hydraulic loadings of 2.5 1/min and 4.0 1/min best for the range of NO3+NO2-N concentrations studied.</p> <p>An energy of activation of 16,500 kcal/mole was calculated for hydraulic loading range of 2.5-4.0 1/min.</p> / Master of Engineering (ME)

<p>The main purpose of this research is to implement and evaluate the effectiveness of a coupled model (MIKE SHE / MIKE 11) for Spencer Creek watershed (Ontario), and later to use this model for climate change impact study using Canadian Global Climate Model (CGCM 3.1) data and Canadian Regional Climate Model (CRCM 4.2) data. Both the CRCM and the CGCM data are downscaled using a Statistical Downscaling Method (SDSM) and a Time Lagged Feedforward Neural Network (TLFN).</p> <p>The hydrologic modeling results show that the coupled model captured the snow storage quite well with a correlation coefficient of 0.5-0.8. It also provided a good representation of evapotranspiration (ET) in the catchment with higher values in late spring and early summer months. The simulated streamflows are consistent with the observed flows at different sites with a Nash-Sutcliffe coefficient of around 0.4-0.5. The model couldn't capture the extreme or mixed events such as freezing rain in winter and rain on snow processes in early spring. Using a conservative climate change scenario, downscaled RCM with TLFN and SDSM yields smaller changes than raw RCM projections, but the downscaling with SDSM produces smaller changes than TLFN. With downscaled GCM scenarios, the coupled MIKE SHE/MIKE 11 model predicted 1-5% annual decrease in snow storage for 2050s and 5-22% increase with RCM scenarios. Similarly, with downscaled GCM scenarios, the coupled model predicted 1-10% increase in annual ET for 2050s and 2-22% increase with TLFN downscaled RCM scenario. But with SDSM downscaled RCM scenario, the model showed around 10% decrease in annual ET. Those results are consistent with the downscaled results for maximum and minimum temperatures. The coupled model predicted 10-25% increase in annual streamflows for all the stations with downscaled GCM scenarios- which is consistent with the predicted changes in the snow storage and ET. With raw RCM scenarios, the model predicted 5- 12% increase in annual streamflow, and 3-30% decrease with downscaled RCM results showing consistency with predicted increase in ET and the negative to small increase in precipitation. Overall, the wide range of projected future changes in hydrologic processes predicted by this study can be useful for understanding the integrated effect of climate change in this complex catchment.</p> / Master of Applied Science (MASc)