title: Biosynthesis of β-Lactones: Origin of the Oxygen Atoms and Mechanism of β-Lactone Ring Formation

contributor:
Harrison, P.H.M.
Chemistry

subject: Chemistry Chemistry

abstract:
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β-Lactones are natural products containing a four-membered lactone ring and are

potent inhibitors of various types of enzymes. The mechanism of β-Lactone ring formation

was examined in vivo in order to identify the genes and proteins that effect cyclization.

Incorporation experiments into ebelactone A, a polyketide-derived β-Lactone from

Streptomyces ahuraviensis, were conducted. Doubly labelled sodium [1-

¹³C,¹⁸0₂]propionate prepared from labelled cyanide and water was fed to the cultures of

the organism to give labelled ebelactone A. ¹⁸0-induced isotopic shifts were observed for

all oxygenated carbon atoms of the molecule indicating that these oxygen atoms are all

derived from propionate. This result is consistent with formation of the β-Lactone ring by

nucleophilic attack of the C-3 hydroxyl group of a polyketide precursor onto the C-l

carbonyl carbon, and excludes other putative mechanisms for ring formation. Ebelactone

A was chemically converted to its N-acetylcysteamine derivative (SNAC). Labelling

experiments to test for conversion of this SNAC derivative to ebelactone A in vivo

showed only a background chemical cyclization reaction.

abstract: Master of Science (MS)


title: Plastic Deformation and Fracture Behavior of AI-Mg and AI-Cr Alloys

contributor:
Niewczas, M.
Materials Science and Engineering

subject:
Materials Science and Engineering
Materials Science and Engineering

abstract: This research concerns a study of the deformation behavior and dislocation substructure characteristics resulting from plastic flow in single phase Al-Mg (0-4.11 at%Mg) and Al-Cr (0-0.36at%Cr) alloys. Tensile tests are performed at 298K, 78K, and 4.2K, and strain rate sensitivity tests are performed at 78K for the Ai-Mg alloys, and at 298K and 78K for the Al-Cr alloys. Resistivity measurements are carried out during tensile tests for all alloys deformed at 4.2K. The resulting structures are then studied using SEM and TEM microscopy. Solute strengthening is seen to occur in both systems, along with significant increases in strength and work hardening capacity in all alloys accompanying decreases in temperature. The limit for benefits from solute strengthening appears to lie close to the solubility limit for the Al-Mg system, but no clear limit is observed in the Al-Cr system. Resistivity data seems to indicate that a critical dislocation density is reached before fracture in all Al-Mg alloys studied, but that this critical density decreases with Cr content. Portevin Le-Chatelier (PLC) type instabilities are observed at room temperature in the Al-Mg alloys only, though both systems exhibit adiabatic shearing processes at 4.2K. A dislocation substructure resembling those observed in other Al-Mg alloys is observed, but the Al-Cr alloy dislocation substructure more closely resembles that observed in pure Al. Both substructures are seen to show greater dislocation density, distributed more homogenously over the structure as temperature decreases.

abstract: Master of Applied Science (MASc)


title: Public engagement - why bother? Exploring the conditions under which public engagement practices in local health care decision making matters

contributor:
Eyles, John
Geography

subject: Geography Geography

abstract:
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Public engagement is increasingly becoming an important part of equitable

decision-making in healthcare. In particular, it is important to ensure that minority

populations can be involved in policy forming activities, given Canada's growing

diverse population. Therefore this research examines the nature and scale of

public engagement occurring with visible minority populations in terms of

enhancing their awareness and access to health care resources. This was explored

within the contexts of general health care services organised through Local Health

Integration Networks (LHINs) in Ontario, Canada, as well as more specialised

health care services, provided through Cancer Care Ontario (CCO). Keyinformant

interviews, focus groups and a document review were utilized to gain

insight into institutional and community perceptions about engagement and its

importance in accessing healthcare services. Findings highlight some of the

barriers and facilitators for engagement of visible minority community members.

The theoretical and policy contributions point to the need create opportunities to

facilitate interrelationships between institutions existing at smaller spatial scales;

therefore allowing community leaders, decision makers, activists and citizens to

exchange skills and knowledge to aid in better understanding of the delivery of

regional health care.

abstract: Master of Arts (MA)


title: "She must assemble": The Modern Hostess in Chopin, Woolf and Fitzgerald

contributor:
O`Connor, M.
English

subject:
English Language and Literature
English Language and Literature

abstract: This thesis examines the hostess figure in Modernist literature from the late nineteenth to early twentieth century as she assembles her environment and, furthermore, her evolving sense of self and "womanhood." The party scene will be examined in three texts to illuminate the concerted work of the hostess to compose her public and private realms and selves. A close reading of these scenes yields a similar observation: each author employs the party scene to dramatize the awakening of their heroine to the fraught duality of her role as a woman subjected to societal demands and private, disquieted stirrings within. In this way, these texts uniquely stage the development of the New Woman of the fin-de-siecle. In conjunction with a historical examination, a consideration of hospitality theory enriches these readings. Jacques Derrida's discussion of the guest-host wager works as a point of leverage in reading the common moment in each party scene when the protagonist's constructed sense of self-as-host reaches an inevitable breaking point and causes the host to reframe his or her sense of self. In each of the three scenes the hostess is left markedly divided with a deeper understanding of her position as a modem woman straddling public and private obligations. This thesis chronologically traces the hostess' increasing development: Kate Chopin frames the earliest fracturing of Edna Pontellier who is left to drift away in The Awakening, in Mrs. Dalloway Virginia Woolf depicts Clarissa Dalloway's jarring evening but allows her to return to her life a quietly changed woman, and ultimately, F. Scott Fitzgerald portrays the hard won social and mental emancipation of Nicole Warren Diver in Tender is the Night. This thesis aims to highlight the party scene and hostess figure as important literary tools that demonstrate the fraught awakening of the New Woman in modernity.

abstract: Master of Arts (MA)


title: Modeling, Analysis, and Detection of Information Leakage via Protocol-Based Covert Channels

contributor:
Khedri, Ridha
Software Engineering

subject:
Software Engineering
Software Engineering

abstract:
With the emergence of computers in every day activities and with the ever-growing complexity of networks and network protocols, covert channels are becoming an eminent threat to confidentiality of information. With increasing sensitivity of data in many computer application domains, the leakage of confidential information can have severe repercussions on the institution from which the information was leaked.

In light of this eminent threat, we propose a technique to detect confidential information leakage via covert channels. We limit our focus to instances where the users of covert channels modulate the information that is being sent; either by encryption, or some other form of encoding.

In the literature, the difference between classes of covert channels under the current classification is unclear. This lack of clarity results in the development of incomplete techniques for modeling, detecting and preventing covert channels. In this thesis, we propose a new classification for covert channels which organizes covert channels into two types: protocol-based covert channels and environment-based covert channels. We also develop a novel, comprehensive model for protocol-based covert channel communication. Using the developed model, we explore the relationship between covert channel communication, steganography and watermarking. The intent is to provide a better understanding of covert channel communication in an attempt to develop investigative support for confidentiality. Finally, we propose a technique for detecting confidential information leakages via covert channels. The technique is based on relation algebra and offers tests for verifying the existence of an abstraction relation which relates the confidential information to the information that is observed to be sent on the communication channel. It focuses on protocol-based covert channels.

With a better understanding of covert channel communication, we are able to develop more effective and efficient mechanisms for detecting and preventing the use of covert channels to leak confidential information in computer systems.

abstract: Master of Applied Science (MASc)


title: Ultrafiltration of Alkalilignin Through Dynamic Membranes Formed of Feed Constituents

contributor:
Benedek, Andrew
Chemical Engineering

subject:
Chemical Engineering
Chemical Engineering

abstract:
Membranes formed by constituents of ultrafiltration feed solutions on a support structure are called dynamic membranes. Lignin has the ability to form a self-rejecting membrane potentially useful for separating lignin from pulping wastes.

Lignin solutions and pulp mill wastes were circulated past support tubes at different operating conditions. A typical product flux was about 7 gal/ft²day with about 99% rejection. The effect of the feed solution concentration, the pore size of the support structure and the cross-flow velocity were small on the membrane performance. A temperature increase from 30ºC to 70ºC increased the product flux by 130%. A higher operating pressure increased the product flux only slightly above a critical pressure of about 80 psi. The product flux was highly dependent on the pH, being e.g. 30 gal/ft²day at pH2 and 7.5 gal/ftday at pH//.

Some chemical additives, reported to alter liquid conformation, were tested and the best results were given by addition of formaldehyde. It increased the product flux at pH2 from 30 gal/ft²day to 42 gal/ft²day. A pretreatment of the carbon support tubes by hydrochloric acid improved the product flux from 6 gal/ft²day to 16 gal/ft²day but the beneficial effect, in this case, was time dependent.

abstract: Master of Engineering (ME)


title: Nd isotope delineation of crustal terranes in the Bancroft area of Ontario and the Saguenay and Baie Comeau regions of central Quebec: Ensialic rifting and arc formation

contributor:
Dickin, Alan P.
Geography and Earth Sciences

subject:
Earth Sciences
Geography
Earth Sciences

abstract:
The Grenville Province is a highly metamorphosed region of the Canadian shield which contains numerous lithotectonic domains of various ages and characteristics all affected by the c.a. 1.0 Ga Grenville Orogeny. The present study investigates, through reconnaissance neodymium isotope mapping, three under-mapped areas of the Province: the Weslemkoon study area of Ontario and the Saguenay and Baie Comeau study areas of central Quebec. These locations represent areas where previous studies have identified the presence of older crustal blocks which predate the Grenville Orogeny. But further detailed mapping is required to test and formulate interpretations regarding their evolutionary history.
 The Weslemkoon Study area is found within the Central Metasedimentary Belt (CMB) of Ontario. The CMB has been interpreted as a composite arc belt (on the basis of structural studies of shear zones) or alternatively, as a failed ensialic rift zone (on the basis of isotope evidence and geometrical relationships). The Grimsthorpe Domain found within the CMB is of major importance in investigating both of these interpretations. In the situation where the CMB is viewed as a composite arc belt, the Grimsthorpe Domain has been interpreted as an allochthon on the basis of its bounding shear zones. However, in current research which views the CMB as a juvenile rift zone, the Grimsthorpe Domain has been interpreted as a horst structure composed of remnant old crust that formed in situ. The latter situation considers evidence from isotope signatures as well as the en echelon geometry of marble domains which are predominant on either side of, but completely absent from the Grimsthorpe Domain. This raises the possibility that the Grimsthorpe Domain did indeed form in situ. The Weslemkoon Batholith largely lies within the Grimsthorpe Domain but extends past the eastern shear zone of the Grimsthorpe Domain. Thus it provides an ideal location to test whether the Grimsthorpe Domain is an allochthon or a horst.
 The present study finds that there are consistent Nd isotope signatures spanning the boundary of the Grimsthorpe Domain indicating that the shear zones are reflective of metamorphism, but not transportation of this block of crust. As well, the extent and geometry of old crust is defined and found to have isotope signatures relating this structure to the flanks of the rift zone and thus strengthening the argument that the Grimsthorpe Domain represents a horst structure. Further, the juvenile and old blocks have a ringed geometry in which inter-fingered lobes are identified.
 The Saguenay and Baie Comeau study areas of central Quebec are located within the Central Gneiss Terrain and Baie Comeau Segment found within the Allochthonous Polycyclic Belt. While anorthosite-mange ritecharnockite- granite suites have received much attention in the literature, the basement rocks have only recently been studied in any detail with identification of Quebecia. Quebecia, a broad juvenile 1.5 Ga arc terrane has been defined on the basis of relatively homogenous Nd isotope signatures indicating a common basement. Previous studies identified a few isolated areas of crust with signatures predating the Quebecia terrane and these are investigated in detail in this study.
 Through more detailed isotope analysis and mapping of the Saguenay and Baie Comeau regions, the extent and geometry of these old blocks of crust have been defined. These old crustal blocks are completely encompassed by the Quebecia arc terrane which the present study interprets as indicating that Quebecia represents a composite arc where fragments of old crust were incorporated into an area dominated by juvenile subduction-related magmatism. These fragments are possibly connected to form a 'panel' of old crust running through the younger Quebecia arc terrane. Hence their identification provides a critical piece of evidence in understanding the geological evolution of the central Grenville Province.

abstract: Master of Science (MS)


title: The relationship between new transportation infrastructure and psychosocial well-being: A case study of the Red Hill Valley Parkway in Hamilton, Ontario

contributor:
Peace, Walter
Geography

subject: Geography Geography

abstract: This research attempts to understand how the alteration of green space to install new transportation infrastructure has impacted the daily life and psychosocial health of area residents. Psychosocial health refers to the distress, dysfunction and disability manifested in a range of psychological, social and behavioural outcomes as a consequence of actual or perceived environmental exposure. A case study was employed using the Red Hill Valley Parkway (RHVP) located in Hamilton, Ontario. To investigate this research problem, a mixed methods approach was utilized with self-administered surveys (N=216) and in-depth interviews (N=21) of residents living within 1000 metres of the RHVP to understand how the parkway has affected the everyday lives of those living in close proximity to the road. The findings do not address specific characteristics of respondents who are more likely to report concerns with the parkway, as well the study may not represent the general population; nonetheless the findings provide us some insight into the lives of those who identify concerns with the parkway and how these concerns have affected their daily life. The findings of this research indicate that concerns are linked to distance as the majority of residents who express concerns about the parkway live within 200 metres of the road. The results suggest that the presence of the Red Hill Valley Parkway and the increase in noise and vehicle exhaust has contributed to negative perceptions of the neighbourhood, has led to an increase in annoyance, activity and sleep disturbances, and impacted the quality of life of residents. Residents experienced a number of psychosocial symptoms relating to the parkway as they no longer are able to use their home or outdoor environment like they used to which was essential for general well-being and daily behaviour. The study concludes by providing recommendations to assist policy makers in eliminating and mitigating such impacts, as well as outlining future studies which should focus on the long-term effects of exposure to transportation infrastructure and traffic on psychosocial health and wellbeing.

abstract: Master of Arts (MA)


title: Psychometric Considerations of the Attention Network Test

contributor:
Shore, David I.
Psychology

subject: Psychology Psychology

abstract: It has been suggested that the human attention system is subdivided into three functionally and anatomically independent networks-the alerting network, the orienting network, and the executive control network. The Attention Network Test (ANT) aims to provide a quick, easy and intuitive tool for measuring the efficiency of these three networks. The ANT, first described in 2001, has become popular in the neuropsychological literature, with some form of the task currently appearing in no less than 65 original research papers. Although several general reviews of the ANT exist, an analysis of the psychometric properties of the ANT is lacking. The present study analyzed the reliability, variance structure, distribution shape, and independence of the three attention network measures provided by the ANT using a multi-study approach with a large sample (N=1129). The findings suggest caution is needed in the collection, analysis, and interpretation of ANT data

abstract: Master of Science (MS)


title: FROM ART TO PART: A SIMULTANEOUS GEOMETRY AND DECORATION WORKFLOW

contributor:
Spence, Allan D.
Mechanical Engineering

subject:
Mechanical Engineering
Mechanical Engineering

abstract: Reproduction of hand crafted 3D shape geometry is an important industrial concept design step employed for items ranging in size and function. Adding surface art work can extend concept design to include essential product information. This thesis describes an equipment and workflow implementation for reproducing both 3D shape and art work. The hand crafted sample shape is laser digitized to obtain the XYZ geometry coordinates simultaneously with the surface gray level. The resulting point cloud is processed and converted to an STL format for plastic rapid prototyping, while the surface gray level information is treated to fit the smoothed surface, and match the reproduction ink jet printing system resolution and specification. Developed software automatically calculates the dot pattern to reproduce the art work onto the correct prototyped surface location.

abstract: Master of Applied Science (MASc)


title: Association Schemes and Delay Analysis in Wireless Sensor Networks with Cluster Tree Topology

contributor:
Zhao, Dongmei
Electrical and Computer Engineering

subject:
Electrical and Computer Engineering
Electrical and Computer Engineering

abstract:
Ubiquitous wireless sensor networks (WSNs) are expected to play an important role in the future society for various applications. As a result, carefully managing the network resources to improve the network performance becomes a hot research topic. In this thesis, we study the perfonnance ofWSNs with a cluster tree topology, where all the cluster heads (CHs) fonn a tree topology. The sensor nodes transmit data to their directly associated CHs, which forward the traffic to the sink through other CHs in the cluster tree.
We first study the associations between sensor nodes and the cluster heads (CHs). In a WSN where there is a strong overlapping coverage area between the CHs, associating the sensor nodes to different CHs may result in different network performance. As the sensor node associations affect the traffic load within each cluster and that between the clusters, timeline of the CHs should be allocated accordingly. We formulate three optimization problems by jointly considering the sensor node associations and CH timeline allocations. The objectives are maximizing the throughput per sensor node, balancing the energy consumption among the CHs, and maximizing the network level throughput, respectively. Conesponding to each of the objectives, a heuristic association scheme is designed and the timeline allocations of the CHs are calculated. Numerical results based on computer simulation demonstrate that the proposed schemes achieve close-to-optimum performance.

In the second part of the thesis we study the end-to-end transmission delay for traffic at different levels of a WSN with the cluster tree topology. The end-to-end delay includes both local transmission delay between the sensor nodes and their directly associated CHs and inter-CH transmission delay between the forwarding CHs along the path to the sink. Given the timeline allocations of each CH for local and inter-cluster traffic transmissions, we find the distribution of the local traffic transmission delay and that of the inter-CH transmission delay. Based on these results, we then derive the distribution of the end-to end transmission delay and the packet drop rate due to excessive delay. The results provide important guidelines for allocating the CH time resources in order to achieve certain delay or packet drop rate performance. By appropriately allocating the CH time resources, it is possible that traffic traversing more hops to the sink experiences better delay performance than that traversing a fewer number of hops.

abstract: Master of Applied Science (MASc)


title: All-Optical Mult~hop Free-Space Optical Communication Systems

contributor:
Hranilovic, Steve
Kumar, Shiva
Electrical and Computer Engineering

abstract:
Free-Space Optical (FSO) communication systems have recently attracted considerable attention in last-mile applications. High bandwidth, unlicensed spectrum, ease of installation, and high security have made them a good candidate for high data rate transmissions. However, distance-dependent atmospheric turbulence and channel loss degrade the optical link reliability and confine FSO systems to short-haul applications. This thesis addresses innovative all-optical relaying techniques to mitigate the degrading effects of atmospheric turbulence-induced fading by relaying data from the source to the destination using intermediate terminals. The proposed techniques, optical amplify-and-forward (OAF) relaying and optical regenerate-and-forward (ORF) relaying, are deployed in multihop FSO systems to extend the maximum accessible communicating distance of high data rate wireless optical systems.
 In all-optical relaying techniques, photo detection is performed once at the receiver and intermediate terminals process optical field envelopes instead of optical intensities. This major difference requires a new definition of channel model for propagation of optical waves through the atmosphere. By using the developed channel model, bit error rate (BER) performance of multihop OAF FSO systems is analyzed through Monte-Carlo simulations. The simulation results indicate that OAF relaying technique mitigates the channel impairments and enhances the BER performance. By employing more relays, longer distances become accessible, however distance improvement decreases due to accumulating background noise at relays. In order to remove background noise effects, another optical relaying technique is developed. The ORF relaying technique eliminates the received background noise at each relay and significantly outperforms OAF systems. For example at high bit rate BR= 10 Gbps, using two equally-spaced OAF relays during a 3 km turbulence-free link increases the total communicating distance by about 1.11 km. Replacing OAF relays by ORF relays extends the total communicating distance to 4.48 km which is 1.66 km longer than the similar OAF FSO system. By deploying more ORF relays, even longer distances are achievable.

abstract: Master of Applied Science (MASc)


title: SCALING ANALYSIS OF MELTING KINETICS IN RANDOMLY PACKED STEEL SCRAP IN ELECTRIC ARC FURNACE STEEL MAKING

contributor:
Provatas, Nikolas
Materials Science and Engineering

abstract:
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This thesis report the results of a simulation study of the melting kinetics of multiple, randomly distributed, steel scrap pieces. The model used is that previously developed by Li [Li, 2006]. The aim of this study was to better understand the universal features governing the kinetics of multi-piece scrap melting in a liquid pool. We observed the formation of a solidified shell and interfacial gap both in a single scrap piece as well as in randomly distributed multiple scrap melting cases. It is shown that the multiple scrap pieces agglomerate throughout the sample due to solidified shell formation.

The key factors affecting melting kinetics of a heat examined were: heat transfer coefficient, initial solid fraction, initial liquid (preheating) and solid temperatures, scrap size and thermal conductivity.

A scaling analysis of simulation data of melting kinetics was conducted, identifying suitable characteristic length and time scales through which the melting kinetics across different parameters and processing conditions could be scaled and thus understood in the context of a unified mathematical description.

abstract: Master of Applied Science (MASc)


title: HYDROLOGIC ENSEMBLE PREDICTIONS USING ENSEMBLE METEOROLOGICAL FORECASTS

contributor:
Coulibaly, Paulin
Tsanis, Ioannis
Civil Engineering

subject:
Civil Engineering
Civil Engineering

abstract:
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The objective of this thesis is to investigate the potential of ensemble

meteorological forecasts (15 members for each day) in improving ensemble flow

prediction up to 14 days ahead. Large scale ensemble meteorological forecasts generated

by the National Centers for Environmental Prediction's (NCEP) Global Forecast System

(GFS) are used. The hydrologic model used in watershed analysis of the study area is

Hydrologiska Byrâns Vattenbalan-avdelning (HBV). The study area is located in the

Saguenay-Lac-Saint Jean watershed in northeastern Canada and comprises the Serpent

River and Chute-du-Diable basins and a reservoir in Chute-du-Diable.

The NCEP ensemble meteorological forecast data is initially used as input in the p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.5px Times} span.s1 {font: 7.5px Helvetica}

hydrological model HBV to simulate ensemble reservoir inflows and the Serpent River

flows for 5 to 14 days ahead. The ensemble inflow and flow forecasts are compared with

the case where only observed historical data are used. The study results show that there is

a significant improvement in the model forecast performance when NCEP forecast data

are used. The improvement for 5 to 14 day forecasts is revealed by an approximately 20%

decrease in root mean square error (RMSE) for both reservoir inflow and river flow. A

decrease in the Brier score (BS) and rank probability score (RPS) indicates considerable

improvement and an increase in the correlation coefficient (r) and the Nash and Sutcliffe

coefficient (R²) is shown for reservoir inflow and the Serpent River flow respectively,

indicating the advantage of using NCEP data. This improvement is also revealed by the p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.5px Times}

visual inspection of scatter plots, hydrographs of ensemble mean and ensemble members.

The hydrologic forecasts are also assessed on a seasonal basis indicating an improvement

in forecasting indicated by a 30% decrease in RMSE during the spring season, and a

decrease in BS and RPS values. For other seasons, specifically autumn and summer, the

use of the ensemble meteorological forecasts do not provide significant improvement

because of the poor skill of predicted precipitation. More accurate predictions of reservoir

inflow and river flow with adequate lead time will assist in improving relevant issues in

water resources management and planning.

abstract: Master of Applied Science (MASc)


title: FREEZE-THAW EFFECT ON THE RESILIENT MODULUS AND ACCUMULATIVE DEFORMATION OF SILTY CLAY

contributor:
Guo, Peijun
Civil Engineering

subject:
Civil Engineering
Civil Engineering

abstract:
The behavior of subgrade soils with different water contents under freeze-thaw conditions is a significant factor to be considered in pavement engineering, since freeze-thaw cycles substantially affect deformation of subgrade under cyclic loading, which in turn influence the performance of pavements.
 In this study, the resilient modulus tests were performed on unfrozen silty clay before and after the first freeze-thaw cycle. Resilient modulus tests were carried out at various water contents including 5%, 8%, 10%, 12% and 15%. The behavior and response of the samples were monitored and recorded, and are compared through this report. In addition to resilient modulus tests, the accumulative deformation of the samples under cyclic loading was investigated. The results reveal that freeze-thaw cycles have the potential to have significant impact on permanent deformation of silty-clay under cyclic load.

abstract: Master of Engineering (ME)


title: UNIMODULARITY IN SOLVING ILP MODELS OF THE GLOBAL ROUTING PROBLEM

contributor:
Terlaky, Tamás
Deza, Antoine
Computational Engineering and Science

subject:
Computational Engineering and Science
Computational Engineering
Computational Engineering

abstract: The global routing problem is becoming more and more important in the design of today's integrated circuits. A small chip may contain up to millions of components and wires. Although global routing can be formulated as an integer linear programming problem, it is hard to solve directly using currently available solvers. We discuss a relaxation of the problem to a linear programming (LP) formulation with a fractional solution. However, the relaxation yields an NP-hard problem. In this thesis, we introduce three relaxations: the primal (Pc), the Lagrange dual (Dc), and the unimodular (PI) formulation. At optimality, all three problems have the same objective value. A new way to tackle the LP problem is introduced: first solve the Dc and try to find Lagrange multipliers in order to build the PI model, from which an integer solution can be obtained directly. An implementation based on the discussed approaches was tested using IBM benchmarks.

abstract: Master of Applied Science (MASc)


title: Susceptibility and Resistance to Complement-mediated Antibody Lysis in Herpes Simplex Virus-infected Cells

contributor:
Rawls, William E.
Biology

subject: Biology Biology

abstract: Herpes simplex virus-infected cell lines were tested for susceptibility or resistance to complement-mediated antibody lysis by means of the 51Cr release test. Certain human cell lines were found to be resistant to lysis. The resistance to lysis could not be correlated with the ability to produce viral progeny or the expression of viral antigens, as detectable by indirect immunofluorescence assays. Adsorption studies permitted a more precise quantitation of antigenic expression. All cell lines expressed similar quantities of antigen, and adsorbed equal amounts of antibody. Resistant cell line consumed complement, but less efficiently than did the susceptible lines. Resistance could not be related to the ability to cap, or to the phase of the growth cycle. Resistance to lysis appeared to be a property of the cell membrane, modified by the insertion of viral specific proteins after infection. Treatment of the immunoresistant cells with neuraminidase, an enzyme which, it has been suggested, non-specifically increases the immunogenicity of target cells, resulted in the reversal of resistance to lysis in all four HSV-1-infected human cell lines, and in two of the four HSV-2 infected human cell lines. Neuraminidase did not act by unmasking viral antigens, as has been previously suggested, nor did it facilitate the binding of antibody to antigen. This was shown by adsorption of HSV-specific antiserum with neuraminidase-treated and untreated cells. Cells treated with neuraminidase consumed less complement than did untreated cells. This suggested that neuraminidase acted by facilating the interaction of complement with the target cell, making complement uptake more efficient.

abstract: Master of Science (MS)


title: Spline Filter for Target Tracking

contributor:
Kirubarajan, Thiagalingam
Electrical and Computer Engineering

abstract: In this thesis an efficient approach to nonlinear non-Gaussian state estimation based on spline filtering is presented. The estimation of the conditional probability density of the unknown state can be ideally achieved through Bayes rule. However, the associated computational requirements make it impossible to implement this online filter in practice. In the general particle filtering problem, estimation accuracy increases with the number of particles at the expense of increased computational load. In this thesis, B-Spline interpolation is used to represent the density of the state pdf through a low order continuous polynomial. The motivation is to reduce the computational load and to improve accuracy. The motion of spline control points and corresponding coefficients is achieved through implementation of the Fokker-Planck equation, which describes the propagation of state probability density function between measurement instants. The solution of the Fokker Planck equation is achieved by calculating the state transition probability matrix. The state transition matrix is calculated using Dirac Feynman approximation. This filter is applicable for a general state estimation problem as no assumptions are made about the underlying probability density. Finally, simulation results are presented to demonstrate the effectiveness of the proposed algorithm.

abstract: Master of Applied Science (MASc)


title: Great Lakes Coastal Wetlands Monitoring and Assessment Techniques

contributor:
Chow-Fraser, Patricia
Biology

subject: Biology Biology Biology

abstract:
The overall objective of this study is to contribute to general knowledge on bioassessment of Great Lakes coastal wetlands. Coastal wetlands (also referred to as marshes) are uriique systems that experience day-to-day changes due to storms, high winds, and rapid changes in barometric pressure, exposing the shorelines to wave conditions; in addition to this annual and seasonal water level flucations contribute to this distinctive ecosystem.

The first chapter examines the influence of gear type and sampling protocol on fish catch data that are used to calculate biotic indices of wetland quality in Lake Huron. We surveyed fish communities in coastal wetlands of eastern Georgian Bay and Long Point Bay, Lake Erie, to determine biases associated with different gear types and sampling protocols. Parallel data collected from 26 wetlands were used to compare species richness obtained by two standardized protocols: fyke nets (set for 24-h parallel to shore) and boat electrofishing (1500 shock seconds during the day). We found differences between sampling protocols with respect to abundances and type of fish caught. Despite this difference, Wetland Fish Index (WFI; Seilheimer and Chow-Fraser 2006) scores derived from data obtained by the two gear types did not differ significantly. By contrast, when data for 6 exposed sites dominated by Scirpus were compared separately, we found significantly higher WFI scores associated with fyke net data compared with electrofishing data, and these differences were sufficiently large that they should not be ignored. We conclude that both methods can be used interchangeably in routine ecological assessments, as long as methods are used within areas of dense submergent vegetation.

The second chapter used zoobenthos as a bio-indicator of wetland quality. "Zoobenthos" used in this study refers to the invertebrate primary and secondary consumers that are found associated with the sediment-water interface, and includes some of the zooplankton (copepods, cladocerans), which are found floating in the water column and many of the benthic invertebrates that reside on top of the sediment or that emerge from the sediment during the 24-h incubation period. It does not include any of the macroinvertebrates that live in emergent vegetation or that glide on the surface tension of the water. We determined that both water quality and aquatic macrophytes significantly influenced the distribution of zoobenthos. However, we also found that exposure also affected the type of invertebrates found in wetlands, regardless of waterquality conditions. We developed 26 metrics that could be used by wetland managers to assess wetland quality based solely on taxonomic composition of zoobenthos.

abstract: Master of Science (MS)


title: COMPUTING REPETITIONS IN STRINGS: CURRENT ALGORITHMS & THE COMBINATORICS OF FUTURE ONES.

contributor:
Smyth, William F.
Computing and Software

subject:
Computing and Software
Computer Engineering
Computer Sciences
Software Engineering
Computer Engineering

abstract:
Repetition is the reality and seriousness of life.
 - Soren Kierkegaard
The study of repetitions exhibits roots in many modern sciences - sinusoidal waves in physics (smooth repetitive oscillations such as the electromagnetic spectrum), highly repetitive DNA in biology (tandem repeats, satellite DNA), regularities of ciphertexts in cryptography and the periodicity of sounds and sequences in music. A string on a given alphabet ∑ provides the simplest common representation of this underlying property. A repetition defined on a string consists of two or more adjacent identical substrings (e.g. abab or aaaa).
A particular problem regarding repetitions is to count the number of different repetitions in a string. Conventional approaches execute in ϴ(nlogn) time (Crochemore, 1981; Apostolico and Preparata, 1983; Main and Lorentz, 1984) and employ computationally heavy preprocessing. An ϴ(n) time algorithm introduced in 2000 (Kolpakov and Kucherov, 2000) prevailed over its slower predecessors by succinctly encoding all repetitions as runs. A run is a maximally periodic (nonextendible) substring. For example, the string abaabaabb encodes 3 runs - (aba)2(ab), aa (twice) and bb. The first of these identifies three repetitions - (aba)2, (baa)2 and (aab)2 In the early part of this thesis, we survey current algorithms for computing all repetitions.

Brute force is the essential drawback of previous attempts for detecting repetitions, despite evidence and proof that their occurrence in strings is sparse (Puglisi and Simpson, 2008). By establishing combinatorial constraints to predict the expected sparsity of runs, extant preprocessing may be reformatted to exclude redundant computations. In (Fan et al., 2006), it was shown that if two runs begin at the same position i, consequently no runs begin at some neighbouring position i+k. This is the fundamental idea behind our combinatorial work, in which we provide well substantiated conjectures, some of which are supported by proofs, implying that three neighbouring squares in a string force a trivial breakdown of the substring beginning at position i into repetitions of a small period.

abstract: Master of Science (MS)


title: Immune Response to Synthesized Pnipam-Based Graft Hydrogels Containing Chitosan and Hyaluronic Acid

contributor:
Jones, K.
Chemical Engineering

abstract:
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Biomaterials are thought to be the magical solution to improving the quality of life and lengthening lifespans of human beings. To date, there is no biomaterial that can completely escape immune responses. However, successes have recently been made in reducing immune responses to biomaterials.P(N-isopropylacrylamide) (PNIPAM), chitosan , and hyaluronan are examples of polymers that are gaining great interest in the field of biomaterials. The most attractive property of PNIPAM is thermo-responsiveness. Adequate literature has been published on improving the mechanical strength of PNIPAM, but not much has been published on host response to PNIPAM based graftpolymers. Chitosan and hyaluronan are generally considered non-toxic and nonimmunogenic.

The first part of this project focuses on the synthesis and characterization of hyaluronan-grafted-chitosan-grafted-P(NIPAM-co-acrylic acid), while the second part examines the effect of grafting on the extent of immune reaction compared to P(NIPAM-co-acrylic acid) alone. The incorporation of chitosan into P(NIPAM-co-acrylic acid), and hyaluronan into chitosan-grafted-P(NIPAM-coacrylic acid) was confirmed by Fourier Transform Infrared Spectroscopy, Nuclear Magnetic Resonance , 2,4,6-trinitrobenzenesulfonic acid (TNBS), and Lower Critical Solution Temperature (LCST) experiments. The optimum molecular p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.5px Helvetica}

weight for P(NIPAM-co-acrylic acid) that could provide sufficient amount of reactive sites while maintaining LCST below 37°C was found to be in the range of 2-2.5kDa. Western blotting results demonstrated that incorporating chitosan into P(NIPAM-co-acrylic acid) reduces the amount of fibrinogen, fibronectin, and vitronectin adsorbed, and eliminates complement component 3 (C3) adsorption.

Furthermore, incorporating hyaluronan eliminates more inflammatory proteins including fibrinogen and reduces Immunoglobulin G (lgG) adsorption. Chitosan-grafted-P(NIPAM-co-acrylic acid) elicited lower levels of inflammatory cytokine release compared to P(NIPAM-co-acrylic acid), but higher than hyaluronan-grafted-chitsan-grafted-P(NIPAM-co-acrylic). In vitro and in vivo results revealed lowest density of leukocytes adhesion to hyaluronan containing surface compared to the other surfaces. The extent and duration of inflammation was reduced on chitosan-grafted-P(NIPAM-co-acrylic acid) and hyaluronangrafted-chitosan-grafted-P(NIPAM-co-acrylic acid) hydrogels.

abstract: Master of Applied Science (MASc)


title: Development of Photonic Integrated Microchip-Based

contributor:
Zhu, Shiping
Xu, Chang-Qing
Zhang, Zhiyi
Chemical Engineering

abstract:
Microchip-based flow cytometry holds promise in replacing conventional flow cytometers, thus providing less expensive point of care alternatives. Although final products are far off, a strong step towards these goals involves developing easy, reliable processes and improved functionality. This study is part of a larger project to develop a photonic integrated microchip-based flow cytometer using optical designs and simulations to imposed stringent requirements in device fabrication. Thus the goal of this work was to perform material selection, process development and device fabrication to meet the stringent optical requirements with an overview of device testing to demonstrate the achievements.
 Materials needed careful selection and include an SU-8 2025 structural layer, Pyrex substrate and a polydimethylsiloxane (PDMS) sealing layer. Mismatched properties of SU-8 and Pyrex have previously provided poor bonding, namely due to surface chemistry and thermal expansion differences. To overcome this, a thin intermediate layer of polymer was introduced relaxing stresses and allowing for chemical linkages. A rough range of 186-600nm was effective and limited optical deterioration.
 Sealing SU-8 devices with PDMS was previously accomplished using mechanical means or low pressure reversible bonding. Strong irreversible bonding was achieved by coating oxygen plasma treated PDMS with 3-aminopropyltrimethoxysilane (APTMS) and bonding the amino groups to residual epoxy molecules on SU-8 surfaces via polycondensation reactions. Bonding could not be broken through rigorous pressure testing, with devices withstanding on average O.6-0.7MPa and up to 2.2MPa before failing at the inlet fluidic connection.
 Post processing procedures required a rough dicing saw compromising the SU-8 structural layer. Reversibly sealed PDMS helped reduce chipping and protect against debris. An intermediate layer thickness of 186nm was efficient and 600nm provided no further improvement.
 These developed processes met the optical constraints imposed and quality devices were fabricated, capable of coupling high power light through on-chip waveguides, exciting fluorescence in microchannels and providing beam shaping.

abstract: Master of Applied Science (MASc)


title: Rpen: A New 3D Pointing Device

contributor:
Leduc, Ryan
Poehlman, Skip
Computer Science

subject:
Computer Sciences
Computer Sciences

abstract:
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Most often the development of human-computer interfaces has been driven by the technology available at the time, and not by human factor issues. The popular 2D mouse is such a device. Through this effort we have developed an input pointing device which builds on tools and skills that humans have acquired through evolution and experience.

Major trends of graphical input apparatus have gone from indirect computer input (mouse or trackball) to direct input (tablet and touch screen). The current and future trends are more towards 3D interaction and ubiquitous input concepts. Our current effort with the rpen falls somewhere in between. \iVhile it is desirable to take advantage of a mouse's device acquisition technique, we need the rpen to be a direct and more natural interactive input device. At the same time, the rpen is a 3D spatial input device, seeking to take advantage of the human knowledge and skills, naturally.

The rpen is implemented on a Linux platform with the help of a kernel level p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.5px Times}

device driver. The device uses an alternating current, electromagnetic motion

tracker to provide six degrees-of-freedom absolute data. It also uses filtering and

smoothing techniques to reduce the effects of electromagnetic distortions in the

sensed data.

With the rpen, a user can define a touch screen anywhere. The touch screen can be of any size and of any orientation, horizontal, vertical or tilted. A drafting board, drawing board or sketch board can be a touch sensitive surface. The basic concept of the rpen is implemented in software and is not dependent on the physical sensor used. So, multiple input modes can be implemented through the software interface and the rpen can switch between these modes seamlessly.

This thesis presents a new 3D pointing device, the rpen, capable of doing both 2D and 3D interaction. As a byproduct of the current study it has beendetermined that the electromagnetic tracker is not suited to function as a motion tracker for any rpen-like generic pointing device.

abstract: Master of Science (MS)


title: Accelerated Optical Flow Computation using Foveated Vision and Compute Unified Device Architecture

contributor:
Capson, David
Electrical and Computer Engineering

abstract:
Optical flow is a well known technique for the measurement of motion in images. Although it has many applications, calculating the optical flow remains computationally expensive and challenging to use in time-critical tasks. This thesis describes an accelerated approach to optical flow computation using foveation and parallel processing on a Graphics Processing Unit (GPU). Foveation reduces the amount of image data to process by mimicking the variable resolution structure of the human visual system. The resulting image data is processed in parallel on a 240 processor GPU to achieve high frame rates on high resolution images. The newly introduced Compute Unified Device Architecture (CUDA) framework is utilized to create an efficient mapping of optical flow and foveation algorithms to the GPU.
 The performance and error of the algorithm is characterized using synthetic and real data. The non-foveated optical flow algorithm is found to perform up to 100× faster than a CPU implementation. Foveated optical flow is found to give an additional performance gain of up to 27× over non-foveated optical flow with a corresponding increase in angular error. The results are shown to match or outperform FPGA and non-CUDA GPU implementations. Finally, the application of the described system to real-time control of a robot arm is demonstrated.

abstract: Master of Applied Science (MASc)


title: Behaviour of Partially Grouted Nominally Reinforced Masonry Shear Walls under Dynamic Loading

contributor:
Tait, M. J.
EI-Dakhakhni, W. W.
Civil Engineering

subject:
Civil Engineering
Civil Engineering

abstract:
The current Canadian masonry standard CSA S304.1 (2004) deals with the design of unreinforced and reinforced concrete masonry shear walls. The use of one or the other type of wall construction is limited to a particular seismic activity zone based on the seismic hazard index. The code does not provide any provisions for partially grouted shear walls in regions with moderate seismic demand. The experimental program described in the thesis focuses on the dynamic performance of partially grouted nominally reinforced concrete masonry shear walls having less steel and larger spacing than specified by the Canadian masonry standard for the minimum seismic requirements.

A total of six reduced scale shear walls were designed and constructed to fail in flexure. A constant axial load was present throughout the test, which represented a single story building. The walls were grouped into three categories, Type I, II and III. Type I and III walls had reinforcement present only at the ends of the wall with vertical reinforcement ratios of 0.12% and 0.20%, respectively. Type II walls had an additional reinforcement located mid-length of the wall with a reinforcement ratio of 0.17%. Two identical walls were tested for each type with the exception of the Type III, where only one wall was tested. The walls were subject to dynamic loading of a scaled 1940 EI-Centro earthquake N-S component. The experimental results were evaluated and discussed pertaining to behaviour, lateral load capacity, stiffness, period, displacement ductility and load reduction factors.

The general behaviour of the tested shear walls was dominated by rocking motion where a full length mortar joint crack developed, along with the yielding of reinforcement. The rocking motion was able to dissipate energy instead of the more common diagonal cracking and crushing of masonry. Type I and II walls had yields close the predicted values, while Type III wall had a lower yield point than predicted. All walls had similar trends of stiffuess degradation. The period increased by a factor of 2 or more during the course of testing. An idealized bilinear envelope was used to calculate the displacement ductility. It was found to be greater than 2 with load reduction factors ranging from 1.9 to 2.6.

It was concluded that nominally reinforced partially grouted walls are potentially viable to be used in seismic zones where the seismic hazard index exceeds 0.35.

abstract: Master of Applied Science (MASc)


title: Dangerous Boys and City Pleasure: Subversions of Gender and Desire in the Boy Actor's Theatre

contributor:
Ostovich, H.M.
English and Cultural Studies

abstract:
This thesis draws on the works of Will Fisher, Lucy Munro, Michael Shapiro, and other critics who have written on the boy actor on the early modem English stage. Focussing on city comedies performed by children's companies, it argues that the boy actor functions as a kind of "third gender" that exceeds gender binaries, and interrogates power hierarchies built on those gender binaries (including marriage).

The boy actor is neither man nor woman, and does not have the confining social responsibilities of either. This thesis argues that the boy's voice, his behaviours, and his epicene body are signifiers of his joyous and unconfined social position. Reading the boy actor as a metaphor for the city itself, it originally argues that the boy's innocence enables him to participate in the games, merriment, and general celebration of carnival, while his ability to slip fluidly between genders, ages, and other social roles enables him to participate in and embody the productively disruptive carnival, parodic, and "epicene" spaces of the city itself. In these spaces, when gender and age expectations are temporarily overthrown, individual bodies can desire, dress, and perform however they want.

In persistently recognising the boy actor's metabolic ability to metamorphose its gender according to his own, or the individual spectator's desire, and in so doing to explore alternative modes of living and structuring families and other social relationships in the city, Amends for Ladies, Epicoene, The Knight of the Burning Pestle, Eastward Hoi, Ram Alley, and Bartholomew Fair offer strategies by which individual bodies in the audience can pursue their own individual alternative modes of living in the city.

I am extremely grateful to my supervisory committee, Doctors Helen Ostovich, Melinda Gough, and Gena Zuroski Jenkins, for their careful reading (and re-reading) of various drafts, and for the swift and thorough commentary that accompanied each reading. Without their assistance, this project would have far less focus, and far more errors. I am particularly thankful for Dr Ostovich's guidance in my consideration of performance practices and interpretation, and for Dr Gough's always helpful recommendations of critical material throughout the year. I am also grateful to Jesse Arseneault, Brandon Kerfoot, Stephanie Leach, and Mathew Martin, who were always willing to read over paragraphs, and who not only listened to me talk nigh-endlessly about boy actors but also provided me with coffee as I did so.

"A thankful [wo]man owes a courtesy ever"!

abstract: Master of Arts (MA)


title: Jory: A Tool for Feature Modelling Based on Product Families Algebra and BDDs

contributor:
Khedri, Ridha
Computer Science

subject:
Computer Sciences
Computer Sciences

abstract:
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Feature models are commonly used to capture the commonalities and the variability of product families. There are several feature modelling notations that correspondingly depict the concepts of feature modelling techniques. Therefore, the tools based on them reflect this diversity in the notations used and the fuzziness of the concepts adopted.

The thesis discusses the design and the construction of a tool that is based on Product-Families Algebra (PFA) and on Binary Decision Diagrams (BDD). The first brings the mathematical formalism to the specifications of product families and the mathematical theory that enables calculations on feature-models. The second brings efficient algorithms in time and in space. Hence, the tool allows several algebraic manipulations of feature models that are specified within the language of PFA. We coined this tool Jory.

The main contribution of the thesis is the design of the tool, and the implementation of four layers of its architectural design. As well, the thesis gives an implementation of multi-sets and the operations on them using BDDs.

Several case studies are presented and used in the validation of the tool. p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.5px Times}

abstract: Master of Science (MS)


title: Effect of number and location of negative trials on a feature positive discrimination

contributor:
Jenkins, H.M.
Psychology

subject: Psychology Psychology

abstract:
Pigeons were trained to discriminate between two displays differentiated only by a distinctive feature on the positive display. The development of a simultaneous discrimination was measured by the percent of key pecks on the positive display that were directed to the distinctive feature. The effect of a) the sequence of positive and negative trials, b) the number of negative trials, and c) the shape of the distinctive feature on the development of discrimination were examined.

An alternating sequence of block of positive trials and a block of negative trials was interrupted by session breaks either between positive trials, or between positive and negative trials. The location of the session break preserved or prevented within session transitions from negative trials to positive. Sequences that preserved the within session transition from negative to positive trials were highly effective in producing control of key pecking by the distinctive feature. Sequences that prevented within session transitions from negative to positive trials were less effective, particularly when the shape of the distinctive feature was less preferred. The more trials in the negative block the more rapidly discrimination occurred. However, not even the longest block was capable of producing control of key pecking by the less preferred distinctive feature when the session break prevented a within session transition from negative to positive trials.

The preparation employed in this experiment was particularly suitable for evaluating the effect of sequential variable on stimulus control. While differential responding between positive and negative displays can be controlled by the sequence of reinforcement and non-reinforcement itself, differential responding within the positive display cannot.

abstract: Master of Arts (MA)


title: Optimal Multi-Time Period Gasoline Blending

contributor:
Mahalec, Vladimir
Computational Engineering and Science

subject:
Computational Engineering
Computational Engineering

abstract: Multi Time period Gasoline blending is an example of multipurpose production system that is designed to produce multiple products by switching from one product to another. Various factors such as demand for gasoline, availability of supply component, and blend recipes vary with time. Task of the gasoline blender is to decide how much of each product to produce at what point in time (lot sizing) and what should be the blend recipe in order to minimize overall cost (optimize the blend recipe) . The production plans need to account for set-up times between blends and to minimize switching between different product blends. Traditional optimization techniques provide a single optimal solution. This research is using evolutionary optimization algorithm called differential evolution to identify multiple solutions t hat all have the same total cost but offer the blend planner multiple choices in terms of how much of a given product to blend at what point in time.

abstract: Master of Applied Science (MASc)


title: Infant Mortality During the Great Depression in Hamilton, Ontario (1925-35): Trends, Causes, and Implications

contributor:
Herring, D. Ann
Anthropology

subject: Anthropology Anthropology

abstract:
Existing historical research on population health in Hamilton, Ontario concentrates on the past 60 years and the beginning of the twentieth century, leaving an unexplored gap between 1919 and the 1950s. Additionally, few health studies focus on the impacts of economic levels on child and infant wellbeing particularly in the early 1900s.

This thesis investigates the impact of the economic effects of the Great Depression on human health through the study of infant mortality in Hamilton, Ontario between 1925-35. Aggregate patterns of temporal, spatial, and seasonal infant mortality are examined in detail in addition to cause-specific mortality based on individual-level data obtained from death certificates. The three aims of this research are to: 1) explore and compare infant mortality trends before and during the Great Depression; 2) determine how the economy affected infant health, and; 3) determine whether these effects were experienced equally across socio-economic strata.

An overall decline in the number and rate of infant deaths was found during the years of the Great Depression, however the working-class immigrant population was found to disproportionately contribute to the municipal infant mortality rates during these years. A review of local history suggests that the efforts of the public health department and the effects of a housing boom in the 1920s created conditions that buffered most infants from the detrimental effects of the economic crisis. The differences in the IMRs between the affluent and impoverished neighbourhoods reflect the underlying economic and political forces responsible for the social segregation in Hamilton.

The findings of this study contribute to the field of anthropology as the effects of the economy on human health are explored through the urban experience of immigrant and local populations. Future research should focus on individual-level analyses and the effects of economic conditions on maternal and fetal health.

abstract: Master of Arts (MA)


title: Automorphisms of Riemann Surfaces

contributor:
Hambleton, Ian
Mathematics and Statistics

subject:
Mathematics
Statistics and Probability
Mathematics

abstract:
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This paper consists of mainly two parts. First it is a survey of some results on automorphisms of Riemann surfaces and Fuchsian groups. A theorem of Hurwitz states that the maximal automorphism group of a compact Riemann surface of genus g has order at most 84(g-1). It is well-known that the Klein quartic is the unique genus 3 curve that attains the Hurwitz bound. We will show in the second part of the paper that, in fact, the Klein curve is the unique non-singular curve in ℂP² that attains the Hurwitz bound. The last section concerns automorphisms of surfaces with cusps or punctured surfaces.

abstract: Master of Science (MS)


title: Sequentially Plasma Activated Bonding for Wafer Scale Nano-Integration

contributor:
Howlader, Matiar
Electrical and Computer Engineering

abstract:
Sequentially plasma activated bonding (SPAB) of silicon wafers has been investigated to facilitate chemical free, room temperature and spontaneous bonding required for integration of nanostructure on the wafer scale. The SPAB consists of surface activation using reactive ion etching (RIE) plasma followed by microwave (MW) radicals. The drop shape analysis and atomic force microscopy (AFM) results show that O2 RIE plasma is the most efficient in removing surface contaminations while keeping smooth surfaces. On the other hand, MW N2 radicals offer highly reactive, smooth and hydrophilic surfaces. These highly reactive, smooth and hydrophilic surfaces allow strong and spontaneous bonding of silicon/silicon at room temperature. Electrical characteristics show that the current transportation across the nano-bonded interface is dependent on plasma parameters. The infrared images show that plasma induced voids' nucleation at the bonded interface is dominated by O2 RIE power over O2 RIE activation time. The bonding strength achieved at room temperature in SPAB is about 30 times higher than that in hydrophilic bonding.
 In order to explore the reliability of SPAB at high temperature, the bonded wafers are annealed from 200 to 900°C. The thermal induced voids' nucleation occurred preferentially at the plasma induced defect sites. The nucleation of void density is quantitatively determined and explained using high resolution transmission electron microscopy (HRTEM) observations. The electron energy loss spectroscopy results reveal the existence of silicon dioxide at the bonded interface. The reduction in bonding strength after annealing at high temperature is correlated to the increase in void density. The plasma induced defect sites such as nanopores and craters are identified using an AFM. The porous surface allows easy removal of interfacial water and spontaneous covalent bonding at room temperature. The HRTEM results confirm nanometer scale bonding which is needed for the integration of nanostructures. Based on the results, a bonding mechanism of SPAB is presented.
 In order to expand the applicability of SPAB for diverse materials, a novel hybrid plasma bonding (HPB) process is developed to achieve void-free and strong silicon/glass and germanium/glass bonding at low temperature. The HPB combines sequential plasma activation with anodic bonding process. Void-free interface with high bonding strength is observed both for silicon/glass and germanium/glass at 200oe. The bonding strength of the silicon/glass and germanium/glass in the HPB at 2000e is 30 MPa and 9.1 MPa, respectively. The improved characteristic behavior of the interface in the HPB is attributed to higher hydrophilicity and smooth surfaces of silicon, glass and germanium after sequential plasma activation and high electrostatic force associated with anodic bonding. Based on the results, a bonding mechanism of HPB is discussed.
 The chemical free strong bonding of silicon/silicon in SP AB at room temperature and void-free strong bonding of silicon/glass and germanium/glass in HPB at low temperature can be applied in spontaneous integration of nanostructures on the wafer scale.

abstract: Master of Applied Science (MASc)


title: Transport of Magnetic Helicity in Accretion Disks

contributor:
Vishniac, Ethan
Physics and Astronomy

subject:
Physics and Astronomy
Astrophysics and Astronomy
Astrophysics and Astronomy

abstract:
Astrophysical disks are found in many areas of astrophysics, from the protoplanetary disks in which planets are thought to be born, to the accretion disks around white dwarfs, merging stars, and black holes. The key to understanding these disks, is to understand how material overcomes the rotational support and acretes. 'Whatever mechanism is responsible must necessarily explain the transport of angular momentum outward.

The current mechanism used to explain this is the magnetorotational instability (MRI). Its ability to transport angular momentum as well as drive a magnetic dynamo, will be discussed in this thesis. The linear equations of motion for a locally Cartesian patch will be solved numerically to get the time evolution of the magnetic and velocity fields. From these solutions, quadratic quantities in the perturbation variables will be calculated, namely the angular momentum and magnetic helicity. The time evolution of these quantities can tell us about the MRI's ability to both transport angular momentum and drive a dynamo through magnetic helicity.

By solving the equations of motion in a locally Cartesian patch of a shearing disk, I have calculated the flux of angular momentum and magnetic helicity. The time evolution of these quantities shows that the ability to transport magnetic helicity is very similar the ability to transport angular momentum. This relation is true for a parameter space which corresponds to the asymptotic limit for the MRI.

abstract: Master of Science (MS)


title: Behaviour of Reduced-Scale Reinforced Concrete Masonry Shear Walls and Components

contributor:
El-Dakhakhni, Wael W.
Drysdale, Robert G.
Civil Engineering

subject:
Civil Engineering
Civil Engineering

abstract:
Reduced-scale models have become an attractive alternative to full-scale experimental laboratory testing due to both physical and fmandal restrictions. In order to have confidence in the ability of a reduced-scale model to replicate fullscale prototype behaviour, test data from reduced-scale research must be correlated and compared to test results of full-scale, prototype, materials. The overall goal of the following thesis is to provide a detailed comparison between third-scale models and full-scale prototype masonry materials, assemblages and wall components. The study includes a total of three phases of experimental testing. The first phase focuses on the individual elements that make up a reinforced concrete masonry shear wall. Elements examined include: third-scale model concrete blocks, mortar, grout and reinforcing steel. The second phase of the reseflrch project focuses on testing different configurations of masonry assemblages in an attempt to combine individual third-scale model elements into a composite assemblage to correlate behaviour to that ofpreviously tested full-scale
assemblages. The third and final phase of research compares two third-scale reinforced masonry shear walls to full-scale walls testing previously at McMaster University. In general, the third-scale model specimens showed good relation to full-scale prototypes for both the individual components and shear walls.

abstract: Master of Applied Science (MASc)


title: Quantifying Coastline Change - Playa Guiones & Playa Pelada, Costa Rica

contributor:
Vajoczki, Susan
Geography and Earth Sciences

subject:
Earth Sciences
Geography
Earth Sciences

abstract: Additional files uploaded from CD

abstract:
This study was conducted over two years (2005 and 2007) and consisted of data collected over one wet season and one dry season at two beaches, separated by a rocky headland, located along the Pacific coast of the Nicoya Peninsula, Costa Rica. Although the beaches are concurrent along a 7 km stretch of coastline, both are characterized by a unique combination of: beach slope, length and shape; sediment composition, size and mineralogy; and vegetation. These beaches have discrete land uses. Playa Guiones is a tourist beach that is experiencing rapid development and Playa Pelada is the only local beach that provides boat access for local fishermen. It was hypothesized that the active tectonism in the region combined with the distinct wet/dry seasons will result in dynamic beaches with distinct morphology.
 The first objective is to quantify and explain changes in sediment accretion or deposition between the two distinct seasons. The second objective is to quantify longer term temporal coastline changes through analysis of air photos and satellite imagery from 1940 to 2005 for the region. It was hypothesized that this time series will provide evidence of the influence of tectonics on coastline position.
 This analysis involves a comparison of Digital Elevation Models (DEMs) created from real-time kinematic GPS data collected in June 2005 and January/February 2007 with aerial photography and satellite imagery representing the period 1940-2005. Results show that from wet to dry season there is substantial net sediment accumulation for Playa Guiones and net sediment erosion for Playa Pelada. It should be noted that the seasons were particularly dry and particularly wet, thus, the results may indicate maximum levels of variation. The time series analyses of the digital imagery show little variation of coastline position during the period of record. The digital imagery was severely limited by the resolution and scale of the imagery. It appears that these beaches experience moderate to large amount of seasonal variation but are relatively stable over a longer time period.

abstract: Master of Science (MS)


title: Powder Die Fill Study for Powder Metallurgy Applications Using New Experimental Approaches

contributor:
Jain, Mukesh K.
Mechanical Engineering

abstract:
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The aim of this research is to enhance performance and durability of the final PM component by improving spatial density homogeneity at die filling stage of powder metallurgy process. In this research, powder die filling processes has been studied using a novel laboratory experimental set-up, with a ring-shaped die, for assessing die fill characteristics of thin, high precision components of interest to Gates Canada.

In this investigation, usefulness of incorporating a perforated plate at the bottom of the feed shoe to improve the density uniformity in the filling condition is assessed. With this arrangement, flow and distribution of powder during the delivery stage is monitored. The powder flow pattern observed through the transparent window is utilized for obtaining full-field displacement data using an optical measurement technique. In addition to the above, several powder flow characteristics during die filling have been studied through a series of high-speed camera recordings. The role of shoe speed, and powder properties in the development of density gradient have been experimentally assessed. A series of full-scale experiments with coloured salt as a powder medium to mimic the iron powder flow have been conducted to understand flow patterns, and segregation of powder during the filling process.

Further, a novel method of density measurement of the part in die-fill condition by heating iron powder with a polymeric resin is explored. Qualitative density data obtained from the die filling experiments, and subsequent porosity data from powder sintering in the die have been compared, to understand the reasons for density gradient in the die-cavity.

abstract: Master of Applied Science (MASc)


title: Faint Members of Distant Galaxy Groups

contributor:
Parker, Laura
Physics and Astronomy

abstract: In this thesis, we present an analysis of ten galaxy groups at z ~ 0.4 using spectroscopic data from the FORS2 instrument on the VLT. This study targets group member galaxies at magnitudes fainter than any previous study at this redshift. Our group sample comes from the Group Environment and Evolution Collaboration, which was originally based upon the second Canadian Network for Observational Cosmology redshift survey. Fifty-two new group members are identified, mostly within the apparent magnitude range of 21.25 < r < 23.25; this accounts for an approximate increase of 25 per cent in the membership of these groups. We combine these new data with previously obtained follow-up spectroscopy and an extensive set of multiwavelength data to compute composite group galaxy luminosity functions and red fractions. Results from the whole sample are compared with subsampIes defined by cuts in group velocity dispersion, radius, and absolute magnitude. Our results indicate that the group environment contains proportionately more bright galaxies than the field (but similar numbers of faint galaxies) and displays little evidence for strong evolution of the luminosity function upon a comparison with lower-redshift samples. In terms of colour, group galaxies are consistently redder than the field. However, there is a strong trend of decreasing red fraction toward fainter magnitudes, in which the group and field environment become statistically similar near the magnitude limit of our sample. The faintest galaxies in our sample are thus predominantly blue, and located in regions outside the virial radius as defined by R200. Overall, our sample's colours follow a general trend of increasing group red fraction with decreasing redshift, as we show in a comparison with the literature.

abstract: Master of Science (MS)


title: On Optimization of Multiuser Multiple Input Multiple Output Communication Systems

contributor:
Davidson, Tim
Computational Engineering and Science

abstract:
This thesis considers the Shannon capacity of multiuser multiple input multiple output (MIMO) wireless communication systems. That is, the fundamental limit on the rates at which data can be reliably communicated. The focus is on scenarios in which the channel has long coherence times and perfect channel state information is available to both transmitters and receivers. The thesis considers two important design problems in multiuser MIMO wireless communication systems: the design of the sumrate optimal input distribution for the MIMO multiple access channel (MIMO MAC), and the design of the sum-rate optimal input distribution for the MIMO broadcast channel (MIMO BC).

The thesis considers algorithms for solving these design problems that are based on the principle of iterative water-filling. The contributions of the thesis are twofold. First, a correct and rigorous proof of convergence of the family of water-filling algorithms is derived. This proof overcomes weaknesses in the previous attempts of others to prove convergence. Second, an efficient algorithm is presented for the water-filling procedure that lies at the heart of the iterative water-filling algorithm. This algorithm will open the door for further efficient utilization of the iterative water-filling algorithm. This novel algorithm is based on the principle of Fibonacci search, and since the iterative water filling algorithm involves repeated water-filling procedures, the impact of this efficient algorithm is magnified.

The outcomes of this research are that the iterative water-filling algorithms are mathematically validated for the above-mentioned design problems in multiuser MIMO wireless communication systems, and that the implementation of these algorithms is made more efficient through the application of the efficient Fibonacci search method for the underlying water-filling procedure.

abstract: Master of Applied Science (MASc)


title: An approximate method for three-body bound atomic systems

contributor:
Bhaduri, Rajat K.
Physics

subject: Physics Physics

abstract: The Feshbach-Rubinow approximation which is one of the many approximate methods to solve three-body problems was first applied to the triton problem. In this approximation, the three-body problem is reduced to an equivalent two-body problem and the total three-body wavefunction is assumed to depend on a single non-negative variable. The problem then reduces to the solving of a single second order differential equation. When this approximation is made in the atomic three-body problem of the helium atom and helium-like ions, the Schrödinger-like equation that is obtained is analytically solvable, yielding reasonable results for the ground-state energy. Calculations have previously been done with just one variational parameter in the variable on which the wavefunction depends. In this thesis, the definition of the variable has been modified on physical grounds to take better account of screening, and contains two variational parameters. Analytic solutions of the differential equation can again be found, and improved numerical results are obtained. These are compared with the results obtained from the more elaborate K-harmonics approach.

abstract: Master of Science (MS)


title: Races Among Men: Masculinity and Interracial Community in South African Cultural texts

contributor:
Strauss, H.
English

abstract:
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This thesis examines interracial community and masculinity in South African literature, film and mass media. It argues that masculinity is intimately tied to histories of racialization and, as such, represents a significant site for the deconstruction of racially segregatory practice and ideology. Beginning with the post-apartheid nation's multicultural self-advertisement as the "Rainbow Nation," which effaces racial difference, this project argues for a conception of community (national and localized) that acknowledges difference and allows for moments of racial tension within the national narrative. My introduction draws on texts from queer theory and critical race theory and my subsequent chapters look at the ways that men construct and reconstruct community in light of the nation's segregatory apartheid history.

My first chapter examines queer masculinity in John Greyson's film Proteus. I suggest that queer narratives have been excluded from the national narrative and that Greyson's film carves out a space for queerness in the nation where it had previously been effaced. My second chapter outlines the ways that white men structure interracial community and their motivations for doing so. I examine the fiction of Damon Galgut and argue that his texts reveal the extent to which "Rainbow Nation" discourse and multiculturalism proceed from the economic and social interests of white men. My final chapter looks primarily at exclusions within the national narrative and questions how we might envision "others" outside community in more ethical ways. I examine K. Sello Duiker's The Quiet Violence of Dreams and interrogate his text for its exclusion of nonnormative masculine bodies and women from its conception of interracial community. In my conclusion, I turn to the recent resurgence of "Rainbow Nation" discourse in the 2010 FIFA World Cup to emphasize the need for a continued interrogation of the way that multicultural discourse excludes bodies from the national narrative.

abstract: Master of Arts (MA)


title: The Effects of Disconnected Entrapped Air on Hydraulic Conductivity in the Presence of Water Table Fluctuations

contributor:
Smith, James E.
Earth Sciences

subject:
Earth Sciences
Earth Sciences

abstract: The hydraulic conductivity of a groundwater system can possess high spatial and temporal variability in the presence of an entrapped air phase (quasi -saturated soils) which is a key factor in controlling hydraulic behaviour. Previous studies have provided evidence of reduced hydraulic conductivity caused by entrapped air; however, these did not address the dynamic behaviour of the entrapped gaseous phase. In this study, the hypothesis that the decreases in hydraulic conductivity caused by entrapped air are sensitive to fluctuations in the water table was tested using laboratory experiments. The effects of applying increasing confining pressures (water table elevation) on the nature of entrapped air and its effects on quasi-saturated hydraulic conductivity was investigated for a range of sands and for air entrapment by both upward water flow and ponded infiltration (downward flow). Laboratory experiments were conducted using the constant flux method on saturated/ quasi-saturated horizontally positioned sand columns using 1% bleach as the solution. Induced pressures ranged from 0 to 250 cm with changes in hydraulic conductivity calculated using collected timed-interval outflow discharge and the pressure gradient measured by a differential pressure transducer. The sand core was also instrumented to measure volumetric moisture (or air) content with time domain reflectometry (TDR) probes. Results show that a 250-cm increase in water pressure above atmospheric pressure induced changes in the volume of entrapped gas according to the ideal gas law indicating the primary and tertiary roles played by air phase compression and capillary pressure, respectively. The reduction in air content at the 250-cm pressure increased the quasi-saturated hydraulic conductivity by a factor of 1.20 to 1.64. The results were fitted to the van Genuchten (1980) and Faybishenko (1995) functions for unsaturated and quasi-saturated hydraulic conductivity, respectively. The changes in quasi-saturated hydraulic conductivity due to changes in air content are expected to ubiquitously occur in the presence of a fluctuating water table. Thus the understanding of this fundamental mechanism and its incorporation into cunent general models of flow and transport will aid in better understanding the unique role of entrapped air in groundwater systems.

abstract: Master of Science (MS)


title: cProgress towards the development of a chemosensory-based biotic ligand model in fathead minnows (Pimephales promelas) and wild yellow perch (Perca flavescens)

contributor:
Wood, C.M.
Pyle, G.G.
Biology

subject: Biology Biology

abstract: Elevated metal concentrations in the aquatic environment may pose a threat to fishes through acute lethal and chronic sub-lethal exposures. To assess the impact of anthropogenic metal contamination on aquatic fauna the Biotic Ligand Model (BLM), a model based on metal-binding to the gills, is now considered to be the best approach for predicting site-specific metal toxicity. The olfactory epithelium (OE) of fishes is exposed directly to the aquatic environment and is vulnerable to waterborne exposures to sublethal metal concentrations. These exposures have been shown to impair the olfactory function of fishes. The goal of this thesis was to begin the development of a chemosensory-based BLM (cbBLM) to predict sub-lethal metal toxicity using laboratory based experiments with fathead minnows (Pimephales promelas, FHM) and yellow perch (Percaflavescens, YP), the latter chronically exposed to metals in the wild. Our results demonstrate that Cu and Cd binding to the OE of fathead minnows was saturable and that increasing waterborne Ca decreases metal accumulation in the OE. The binding of Cd to the OE of wild yP was saturable but the binding of Cu was not. Acute exposure of the OE to Cu impaired peripheral olfactory function in FHM as demonstrated by a decreased electrophysiological response but this was not observed for exposures to Cd. Moreover, the peripheral and central olfactory system functions of chronically metal-exposed wild YP were also impaired as indicated by an elevated electrophysiological response and a lack of behavioural response to conspecific skin extracts. This is the first study to examine the binding characteristics of Cu and Cd to the OE of fishes and to relate this metal accumulation in the OE to the impairment of peripheral olfactory function. This information can now be used to begin development of a cbBLM. A cbBLM would use metal-OE binding constants, site-specific water chemistry, and ethological or ecological endpoints. Such models would be useful in devising environmental regulations to predict and therefore prevent chronic, sub-lethal metal toxicity in fishes and improve ecological risk assessment.

abstract: Master of Science (MS)


title: Can you McGurk yourself? Self-face and self-voice in audiovisual speech

contributor:
Shore, David I.
Psychology

subject: Psychology Psychology

abstract:
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This experiment used the McGurk effect to test the influence of identity on audiovisual speech. Participants recorded disyllables which were used to create McGurk stimuli. These stimuli were further manipulated so that the facial and vocal identities in each were either from the same speaker (matched) or from two different speakers (mismatched). When identities matched, self-produced speech was less susceptible to the McGurk effect. When identities were mismatched, participants were less susceptible to the McGurk effect if hearing their own voice, but were not affected by seeing their own face. These results suggest that vocal identity influences speech processing and that facial identity is processed independently of speech.

abstract: Master of Science (MS)


title: A context aware framework for product based software certification

contributor:
Janicki, Ryszard
Wassyng, Alan
Computing and Software

subject:
Computer Sciences
Computer Sciences

abstract:
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Software certification is becoming a reasonable expectation from the ever growing number of software users. The process of software certification could be described as a process in which an auditing body ensures that the product conforms to certain requirements. The certification models which were analyzed included product based, component based and model based. With our results and findings we have developed a proof of concept context aware framework for product based software certification. The proposed product based software certification process is structured on component based certification principals, while the general core of the certification process is composed from known software certification models.

The framework was developed within an OSGi (Open Service Gateway initiative) environment which is being managed by a collection of automation scripts. The certification models which we reviewed did not represent their knowledge formally and did not have any mechanisms to derive indirect knowledge. To address this issue, we have developed an upper ontology to formally model higher level concepts for the certification, and described a general metric for assigning consistent weights to ontology classes. The framework provides a dynamic environment for the certification process by integrating development and certification domains with the help of ontology. Its main objective is to allow the certification process to be able to adjust to ever changing certification demands and extend more easily into different domains.

The developed ontology can maintain many properties and attributes, but for some of these the measuring mechanism are unknown. Therefore, we have described the process on how to derive software metrics for measurable and subjective attributes which can be used to evaluate product, processes and resources. In conclusion, we have outlined some areas for future research.

abstract: Master of Science (MS)


title: Interactions between microbial organisms and polycyclic aromatic hydrocarbons, as investigated through the use of phospholipid fatty acid analysis

contributor:
Slater, Gregory F.
Geography and Earth Sciences

subject:
Earth Sciences
Geography
Earth Sciences

abstract:
PAH contamination is a significant threat to human and ecosystem health worldwide. The development of novel, efficient bioremediation systems can serve to reduce this threat by more effectively removing PAHs from contaminated environments. An improved understanding of the interactions between microbes and P AHs is essential to developing better methods to monitor P AH biodegradation, which should in turn lead to improvements in actual PAH biodegradation. This thesis developed novel process level and community-level understanding of the responses of microbes to PAH contamination, knowledge which could prove useful in the development of improved techniques for monitoring and enhancing PAH biodegradation.
 The first paper (Chapter 2) examined the response of microbial communities to P AH contamination, through PLF A analysis of specific microbial communities in Hamilton Harbour, Ontario, Canada. Increased PAH contamination was found to have caused reductions in microbial biomass, and while community composition was different between sites exposed to high and low levels of PAH contamination, none of the differences in community composition could be definitively identified as having been caused by the presence of PAH. The PAH profile at the less contaminated study site was found to have changed relative to a previous study, suggesting either a change in PAH source occurred, or resuspended PAH-contaminated sediment from elsewhere in the harbour was deposited at that site.
 In the second paper (Chapter 3), a novel approach using stab le carbon and radiocarbon PLF A analyses was used to establish bacterial preference for P AH as a carbon source and identify microbial carbon cycling pathways in P. frederiksbergensis bacteria. Stable and radiocarbon isotopic analyses of P. frederiksbergensis PLF A suggested P. frederiksbergensis metabolism was heterotrophic, but it was found to primarily utilize dissolved inorganic carbon (DIC) as a carbon source for PLF A biosynthesis. Isotopic data suggested metabolism of organic carbon was minimal, and as such, P. frederiksbergensis is most likely an unsuitable candidate organism for use in in situ PAH biodegradation projects.
 Increased knowledge of microbial carbon cycling pathways and microbial community responses to PAH contamination will lead to improvements in P AH remediation, in turnleading to improvements in ecosystem health and reduced exposure risks to humans.

abstract: Master of Science (MS)


title: A Multiple Hypothesis Tracker with Interacting Feature Extraction

contributor:
Kirubarajan, T.
Electrical and Computer Engineering

abstract: The multiple hypotheses tracker (MHT) is an optimal tracking method due to the enumeration of all possible measurement-to-track associations. However, its practical implementation is limited by the NP-hard nature of this enumeration. To bound the computational complexity, some means of limiting the number of possible associations is required. Typical solutions include the interposition of rules to guide the pruning and merging of tracks. Other proposals have shown that the performance of a tracker, MHT or not, can be improved using feature information (e.g., signal strength, size, type) in addition to kinematic data. The inclusion of feature information allows for the discrimination to further gate the data associations. However, in most tracking systems, the schemes to manage the data association problem are extraneous to the Bayesian framework of the MHT. Further, the extraction of features from the raw sensor data is typically independent of the subsequent association and filtering stages. The features are then used in either an ad hoc way or are they are fused with the MHT tracker; they are not used intrinsically within MHT framework. In this thesis, a new approach whereby there is an intrinsic interaction between feature extraction and the MHT is presented. The measure of the quality of feature extraction is input into measurement-to-track association while the prediction step feeds back information to be used in the next round of feature extraction to increase the information available a priori. The motivation for this forward and backward interaction between feature extraction and tracking is to improve the performance in both steps. This approach allows for a more rational partitioning of the feature space, removing unlikely features from. the assignment problem. In addition, a track-specific detection probability becomes available to the prior. This probability significantly improves the coasting behavior when measurements are not available for track continuation. Simulation results demonstrate the benefits of the proposed approach.

abstract: Master of Applied Science (MASc)


title: Effects of Waste Glass and Polymer Addition on the Performance of Concrete Masonry Blocks

contributor:
Chidiac, Samir E.
Civil Engineering

subject:
Civil Engineering
Civil Engineering

abstract:
Concrete masonry blocks are widely used in North America and the world; however, production poses some environmental implications, specifically the depletion of natural resources and contribution to the release of carbon dioxide into the atmosphere. Accordingly, methods to improve the sustainability of the industry need to be developed. The replacement of cement with post -consumer waste glass powder and/or the replacement of fine aggregate with post-consumer waste polymer in the production of concrete blocks are proposed as potential options to reduce the environmental impact of block production while maintaining adequate block performance.
 The effect of using glass powder and polymers on the block and prism properties has been analyzed to determine the most effective implementation of these post-consumer waste materials. Physical properties, mechanical properties and alkali-silica reaction of the blocks and the mechanical properties of the prisms were tested. From the experimental program, it was determined that replacing Portland cement with waste glass powder up to 25% had no detrimental effect on the block and prism properties. Replacing the sand with polymer aggregate was found to have a detrimental impact on the strength of the block. The effect of adding up to 6% polymer aggregate as sand replacement on the prism mechanical properties was found to be minimal. The reduction in block compressive strength when polymer aggregates are used is attributed to the increase in the material's porosity.

abstract: Master of Applied Science (MASc)


title: A PML for Electroacoustic Waves in Piezoelectric Materials using FDTD

contributor:
Bakr, Mohamed H.
Haddara, Y.
Electrical Engineering

abstract:
An improved Perfectly Matched Layer (PML) boundary condition is introduced that addresses the previously reported instabilities. A PML for acoustic waves is derived by closely following Bérenger's derivation of a PML for electromagnetic waves. A new matching condition is developed to relate the velocity and stress loss-coefficients similar to the matching condition defined for electromagnetic waves.
 Whereas, the spatial and temporal derivatives are related by simple scalars in Maxwell's equations, elastodynamic equations describing waves in piezoelectric materials require the use of tensor quantities whose general forms are material dependent.
 In practice, SAW generation is often also accompanied by some small creation of SAWs, which act as parasitic waves. It is thus desired to remove the reflection of these waves from the bottom, in both physical SAW devices and in modeling.

abstract: Master of Applied Science (MASc)