title: Frequency Doubling in NiSO4 • 6 H2O

contributor:
Summers-Gill, R. G.
Physics

subject: frequency, doubling, amplitude, dipole, relation

abstract:
 Using a Q-spoiled Nd-glass laser, an experimental investigation of frequency doubling in NiSO4•6 H2O was carried out. The frequency doubling was observed to occur at a phase matching angle of 56° ± 1°. Experimentally, it is shown that the fundamental frequency at λ = 1.06 μm is an O-ray while the doubled frequency at λ = .53μm is an E-ray. Since the amplitude for electric dipole frequency doubling in NiSO4•6 H2O is zero, these observations are unusual. The observations are attributed to magnetic dipole and/or electric quadrupole frequency doubling. Evidence to support this view comes from the magnitude of the effect and from its azimuthal dependence. The electric quadrupole type frequency doubling is consistent with the data only if the susceptibility coefficients satisfy the relation
QאEE =1/2 (QאEE - QאEE )
1212           1111    1122

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: An Investigation of Radiation-Induced Mitotic Inhibition in L-Strain Mouse Cells

contributor:
Schneider, D. O.
Biochemistry

subject: radiation-induced, mitotic, inhibition, mouse, cells

abstract: The variation in sensitivity of L60T cells to gamma rays has been studied as a function of position in the cell division cycle. For a dose range of 0-12,000 rads, no significant variation was found for mitotic delay. Such was not the case for sensitivity to cell killing, which was found to increase as the cells passed from G1 through S to G2 of the division cycle. The results of mitotic delay are in disagreement with results published by other workers although the survival data agree with previous reports for a similar cell line. Results reported in connection with cell cycle determinations and mitotic delay suggest that the existence of a repair cycle operating concurrently with the normal cell cycle may be postulated. The theoretical treatment of mitotic delay given by Lea is examined and is not found to describe adequately the present results. Finally, the evidence reported here suggests that mitotic delay and radiation lethality are not separate manifestations of the same phenomenon. Experimental materials for further investigation into the repair processes involved are suggested.

abstract: Thesis

abstract: Master of Science (MSc)


title: IMPACT OF TRIBOSYSTEM COMPATIBILITY ON TOOL WEAR AND SURFACE INTEGRITY

contributor:
Veldhuis, Stephen
Mechanical Engineering

subject:
Machining
Surface Integrity
Tribological compatibility
Tool wear
PVD coating
Ball nose end milling
Tribofilms

abstract: H13 tool steel is widely used in the mold and die industry. Due to tighter geometric tolerances and higher quality expectations, the use of hard machining has increased over the years. Hard machining refers to the machining of materials in their hardened state. The challenges with hard machining are rapid tool wear and maintaining a high surface integrity of the machined surface. Surface integrity is measured in terms of surface roughness, residual stresses, presence of surface and subsurface cracks, and the quality of the developed microstructure. In order to minimize wear and improve product quality, researchers are working on the development of different tool coatings. Some of the recent tool coatings function by adapting to their environment using heat to form thin layers of oxides, referred to as ―tribo-films‖, on the surface of the tool. If engineered properly, these tribofilms can prolong tool life and improve the surface integrity of a hard machined surface. A titanium based nano multi-layered coating (TiAlCrSiYN/TiAlCrN) has been developed by researchers at the MMRI. The tribological performance of two different coatings TiAlCrSiYN/TiAlCrN and TiAlCrN were tested in a hard machining metal cutting process. The impact of these coatings on tool wear, Cutting process (Chips) and Surface Integrity (Quality of machined surface) was assessed. This research involves characterizing the coating to understand how the formation of different oxide films (tribofilms) effect tool wear and surface integrity. The generation of these tribofilms is sensitive to coating composition and cutting condition (temperature/pressure). Next, an in-depth characterization of the chips produced during machining was carried out as part of studying the effect of different tribological conditions between the tool and workpiece. The chip's hardness, oxidation, chip formation mechanism and topography as the chip slid against the cutting tool surface was studied. Also, the Surface integrity of the machined part was investigated, considering its microstructure, residual stresses and surface roughness. Lastly, tests were performed in an attempt to accelerate the generation of beneficial tribofilms. Results indicate significant improvement in wear life and surface integrity of the machined surface due to the generation of tribo-films in this machining application.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Humour and Wit in the Paraclausithyra of Horace and Propertius

contributor:
Murgatroyd, Paul
Classics

subject: Paraclausithyron Propertius Horace Classics

abstract: The goal of this thesis is to show how the Roman elegists Horace and Propertius adapted the poetic theme of the paraclausithyron (the lament of the locked-out lover) to be a humorous criticism of other elegiac poets and lovers by employing inversions, reversals and parody into their poems. At the time of writing, this was a topic not covered adequately by commentators of the works, if discussed at all. Humour in particular has been greatly overlooked by the academic community in regards to these poems. The work is based upon my own close readings of the primary texts in addition to secondary scholarship. My hope is that this helps to change the way these poems are viewed: instead of seeing them as serious outpourings of emotion, they should be viewed as light-hearted, comedic works.

abstract: Thesis

abstract: Master of Arts (MA)


title: Genetic diversity and the risk for dysglycemia: a study of South Asian and white Caucasian populations.

contributor: Clinical Epidemiology/Clinical Epidemiology & Biostatistics

subject:
Population genetics
Dysglycemia
Type 2 diabetes
Race
Ethnicity
South Asians
White Caucasians
White Europeans

abstract:
Background: Type 2 diabetes affects approximately 8% of the world’s population. Individuals of South Asian ancestry tend to develop metabolic abnormalities, leading to diabetes, at lower measures of absolute obesity and approximately 10 years earlier than white Caucasians. Current literature is unclear on the source of this ethnic heterogeneity; the variation in risk cannot be explained by lifestyle factors alone. The overarching aim of this thesis is to explore the role of genetic variants and epigenetic differences to explain the greater risk for type 2 diabetes among South Asians.

Methods: We first conducted a systematic review of the literature to ascertain the genetic risk from known single nucleotide polymorphisms (SNPs) among South Asians. We then compared these risk estimates to those from white Caucasians in a cohort of 69,033 individuals. Second, using the EpiDREAM prospective cohort study of individuals at high-risk for diabetes, we assessed the impact of genetic burden for impaired pancreatic beta-cell function alone and together with abdominal obesity on glucose traits. Ethnic heterogeneity in this interaction was also studied. Lastly, using data from two Canadian birth cohorts of South Asian and white Caucasian ancestry, we investigated ethnic differences in the epigenetic architecture for genes known to be implicated birth weight and length, as both are associated with the future risk of adult diabetes.

Results: The systematic review identified 15 SNPs robustly associated with type 2 diabetes in both South Asians and white Caucasians. The magnitude of risk and allele frequency of these genetic variants did not differ between the ethnic groups. Additionally, we identified 8 novel polymorphisms implicated in diabetes only among South Asians. Second, using data from the EpiDREAM study, we identified an interaction between cumulative genetic burden of beta-cell impairment, measured using an un-weighted genotype score, and abdominal obesity on glucose traits in South Asians, but not white Caucasians. Third, our investigation of differential DNA methylation between the ethnic groups revealed seven CpG sites for which changes in methylation corresponded to alterations in birth weight among white Caucasians, but not South Asians. An independent agnostic genome-wide search identified methylation levels at three CpG sites that appear to uniquely modulate birth weight in South Asians.

Conclusions: Overall, our results indicate that the greater risk for metabolic traits in South Asians likely does not result from common genetic variants shared by both South Asians and white Caucasians. Rather, differences in risk may be additionally influenced by unique risk variants in South Asians. Furthermore, it appears that the risk from a genetic impairment in South Asians may be magnified by abdominal obesity.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Neutron Scattering Studies of Solid Methane

contributor:
Collins, M. F.
Physics

subject: neutron, solid, methane, spin, cross section

abstract:
 The total scattering cross section of solid methane has been measured for temperatures in the range from 4.2°K to 95°K. An anomalous increase in the total scattering cross section was observed at temperatures below 5°K. The effect is ascribed to conversion between nuclear spin species. Such spin conversion had been indicated by specific heat and NMR measurements; the present results give an independent confirmation of this. Calculations of the equilibrium value of  at 4.2°K give values lower than those obtained in the NMR work. The specimens used in the present work come to spin equilibrium in times much less than 20 minutes. This is less than the value of 90 minutes for pure methane seen by NMR; however, very small amounts of oxygen impurity in the specimen are known greatly to decrease this time.

  An abrupt change in the total scattering cross section at the 20°K phase transition is explained by a change in the rotational freedom of the molecules to a more strongly hindered state below the phase transition. In the region above the transition, the Krieger-Nelkin approximation for the total cross section was fitted to the observed temperature dependence of the cross section, treating the effective mass as a free parameter.

abstract: Thesis

abstract: Master of Science (MSc)


title: The Immunological Response in Rabbits to Carrageenans, Sulphated Galactans Extracted from Marine Algae

contributor:
McCandless, E. L.
Biology

subject: immunological, rabbits, sulphated, galactans, marine, tissue, growth, structure

abstract: Carrageenan, a mixture of sulphated galactans extractable by hot water from certain marine algae, has been known for its activity in a reversible stimulation of connective tissue growth. One subcutaneous injection of this polysaccharide elicits a granuloma formation which regresses after a few weeks. A single injection after regression results in heightened response; this suggested an immunological reaction. Serial injections of either lambda or kappa carrageenan into rabbits resulted in the formation of precipitins. The present study gives both qualitative and quantitative studies of the reaction involved. Fractions of carrageenans from different species of marine algae were tested for their ability to precipitate either anti-lambda carrageenan antiserum or anti-kappa carrageenan antiserum. Deductions were made from the data as to the structure of the polysaccharides.

abstract: Thesis

abstract: Master of Science (MSc)


title: The Design of Electric Vehicle Charging Network

contributor:
Huang, Kai
Computational Engineering and Science

subject:
Electric Vehicle
Charging Station Location
Optimization
Partial Coverage
Geometric Segmentation

abstract: The promotion of Electric Vehicles (EV) has become a key measure of the governments to reduce greenhouse gas emissions. However, range anxiety is a big barrier for drivers to choose EVs over traditional vehicles. Installing more charging stations in appropriate locations can relieve EV drivers’ range anxiety. To help decide the location and number of public charging stations, we propose two optimization models for two different charging modes - fast and slow charging, which aim at minimizing the total cost while satisfying certain spatial coverage goals. Instead of using discrete points we employ network and polygons to represent charging demands. Importantly, we resolve the partial coverage problem (PCP) by segmenting the geometric objects into smaller ones using Geographic Information System (GIS) functions. We compare the geometric segmentation method (GS) and the complementary partial coverage method (CP) developed by Murray (2005) to solve the PCP. After applying the models to Greater Toronto and Hamilton Area (GTHA) and to Downtown Toronto, we show that that the proposed models are practical and effective in determining the locations and number of required charging stations. Moreover, comparison of the two methods shows that GS can fully eliminate PCP and provide much more accurate result than CP.

abstract: Thesis

abstract: Master of Science (MSc)


title: An Empirical Study of Goodwin Growth Models

contributor:
Grasselli, Matheus R.
Mathematics and Statistics

abstract:
Three dynamic macroeconomic models have been econometrically tested for ten OECD
countries. One of them is a classic model developed by R.M. Goodwin on the lines of
Lotka-Volterra predator prey model of mathematical biology, the second is an extension developed by Desai incorporating inflation and the third is a model developed
by van der Ploeg incorporating a generalized production function. We start with estimating parameters and equilibrium of the Goodwin growth model, we then discuss
data issues and reasons of poor estimates in a well-known paper by Harvie. Next we
analyze the impact of inflation on the bargaining power of the agents and on the equilibrium through Desai's model. Finally, we estimate CES production function and
equilibrium estimates of the van der Ploeg model. We  find that the estimates of the
van der Ploeg model are within the bounds of observed values for 6 out of 10 countries
examined. Moreover, the error of the model is much less than suggested by previous studies. This implication is important and encouraging for further econometric
estimation of generalized dynamical models in macroeconomics

abstract: Thesis

abstract: Master of Science (MSc)


title: Body Image: A Consideration of Immigrant Status, Ethnic Minority Status and Immigrant Concentration

subject: body image dissatisfaction; body image distortion; scoping review; immigrant generational status; ethnic minority; adolescents; interpretive description; immigrant concentration; multi-level modeling; sex

abstract: Despite the developmental and clinical importance of body image during the pre-adolescent and adolescent years, there remains a dearth of information on the body image experiences of immigrant children and adolescents.  This thesis represents a purposeful attempt to examine body image experiences among immigrant and ethnic minority children and adolescents in Canada and the United States (US). Specifically, the thesis integrates multiple methods (scoping reviews, qualitative interpretive description, quantitative multi-level modeling) and samples (clinical and population-based samples) to systematically contribute to the academic literature focusing on body image experiences among immigrant and ethnic minority children and adolescents in Canada and the US. Consisting of four conceptually related studies, this thesis makes the following methodological and conceptual contributions to epidemiological and clinical research and practice. First, the results from all four studies point to the need to develop standardized approaches for identifying and classifying immigrant and ethnic-minority children and adolescents. This will substantially increase the field’s ability to systematically characterize the nature and magnitude of body image dissatisfaction, body image distortion, and their associated outcomes among immigrant and ethnic minority children and adolescents. In addition, this systematic classification has the potential to inform the development or adaptation of universal and targeted preventative intervention strategies. Second, Study’s 1 and 2 demonstrate a clear need to further examine the constructs and experiences of acculturation and acculturative stress in relation to the body image experiences of immigrant and ethnic minority children and adolescents.  The literature is unclear with respect to whether or not immigrant adolescents’ adoption of the values, behaviours and ideals of the Canadian or US culture increases their risk for body image concerns. On the other hand, we are also unclear as to whether or not immigrant adolescents’ retaining of the values, behaviours and ideals of their culture of origin may offer protection from poor body image experiences. Similarly, we are unclear about whether—and to what extent—stress as a result of adolescents’ acculturative experiences (i.e. acculturative stress) influence the onset or pervasiveness of body image concerns. Greater understanding about these constructs and processes and the extent to which they are implicated in the body image experiences among immigrant children and adolescents has the potential to inform culturally competent and targeted intervention approaches. Results from Study 3 indicate that immigrant adolescents have body image and appearance-related concerns that extend beyond what has typically been found among non-immigrant adolescents. More specifically, immigrant adolescents are concerned about the appearance of their skin (texture, complexion), their hair, their teeth, as well as other bodily features. It would be prudent for future researchers and clinicians to consider this information in relation to measuring, classifying and addressing body image dissatisfaction among immigrant adolescents. Finally, Study 4 demonstrates that females and first generation immigrants with body image dissatisfaction are at significantly elevated risk for body image distortion. This suggests that the assessment and intervention for body image dissatisfaction—particularly among females—soon after the migratory experience may play an important role in reducing body image distortion experiences. Taken together, the findings of this thesis strengthen the body image field by demonstrating that there are several unique aspects about being an immigrant  that can influence adolescents’ body image experiences; and therefore, should be considered from a conceptual and methodological standpoint in future research and implementation of body image interventions.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)

abstract: Body image dissatisfaction and body image distortion have been linked to serious psychological outcomes, including depression and eating disorders. Yet, we know very little about the nature of these experiences among immigrant and ethnic minority children and adolescents. This thesis uses qualitative and quantitative methods, as well as general population and clinical samples to investigate body image dissatisfaction and body image distortion among immigrant and ethnic minority children and adolescents in Canada and the United States. Results provide important information that can inform the development of preventative interventions targeting body image dissatisfaction and body image distortion among immigrant and non-immigrant children and adolescents.


title: Analysis of Point Processes

contributor:
Chorneyko, I. Z.
Mathematics

subject: point, processes, Poisson, asymptotic,

abstract: This thesis is concerned with investigating point processes and the numerous methods available for obtaining information about them.

abstract: Thesis

abstract: Master of Science (MSc)


title: Thermal Neutron Capture Studies of Some Light Odd-Odd Nuclei

subject: thermal, neutron, odd-odd, nuclei, gamma ray, spectra, capture

abstract: Thermal neutron capture studies have been made of the odd-odd nuclei, 20F, 24Na, 28Al, 32P, 36Cl and 40K. The gamma ray spectra have been studied using a Ge(Li) pair spectrometer and revised decay schemes are presented for these nuclei. The Q-values and gamma ray multiplicities have been obtained for the reactions studied. The average partial widths for primary Ml and El transitions have been calculated for the six nuclei and compared with the theoretical estimates. The features of the capture gamma ray spectra are discussed and it is observed that for the six nuclei studied, the total intensity in the spectrum above the energy of 0.3 times the Q-value is nearly the same (~1.4 photons/capture).

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: THE FEMINIST FEMALE SLAVE:  FEMALE SUBMISSION, RELATIONAL AUTONOMY, AND BELONGING

contributor:
Gedge, Elisabeth
Philosophy

subject:
BDSM
Feminist Philosophy
Autonomy
Relational Autonomy

abstract: This project introduces the case of the Feminist Female Slave [FFS], a female submissive in a BDSM relationship with a male Master. This case is used in order to strengthen discourse in three main areas: feminist relational autonomy, BDSM theory, and feminist community politics. I argue that the FFS offers a case in which feminist autonomy theorists can serve to grow and develop their own approaches in a way that is inclusive of the diversity of women’s sexual expression, as she challenges our narrow notions of female subservience and asks us to rethink what it means to express an autonomous women’s sexuality. In BDSM theory she asks us to reflect upon our reliance upon superficial notions of consent and the lack of space for a critical dialogue, and finally, in feminist politics she asks us to consider what it means to belong to feminist communities, or what it means to feel as if one can lay claim to a feminist identity. Each of these considerations is brought to light in this project because of the interesting balance that the FFS’s relationship holds between her feminist identity, sexual politics, and sexual and romantic practices.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)


title: Water, Sanitation, and Hygiene as a Gender Based Violence Risk: How Inadequate Access to Clean and Reliable Water Increases Rates of Violence Against Women in East Africa

contributor:
Watt, Susan
Social Work

subject:
Water
Sanitation
Hygiene
Women
Africa
East Africa
Violence
Gender Based Violence
Animal Attacks
Child Violence
Sepsis
Anemia
Cholera
Worm Infestation
Miscarriage
WaSH

abstract: This research aims to further explore the linkages between poor WaSH realities and women’s development to understand how the burdens and risks associated with inadequate water resources diminishes both their health and safety. Specifically, a significant goal of this project is to understand the way in which rates of violent attacks increase as access to water decreases. Attempting to capture this violence in all its various forms, this study hosts conversation surrounding the way that a lack of clean, dependable water sources can increase a woman’s chances of experiencing various forms of violence.

abstract:
Accessing clean water and adequate sanitation poses significant risks to the health and wellbeing of women and girls in East Africa. Without having access to local and dependable sources of water, the prevalence of water-borne diseases, health and safety hazards, and social barriers increase. Grounded in Feminist and Structural Functionalism theories, this research was designed to better understand Water, Sanitation, and Hygiene (WaSH) realities and the various types of associated burdens and risks. Using focus groups and key informant interviews, 36 health care professionals from various East African countries, such as Uganda, Tanzania, Ghana, and South Sudan, were solicited in an effort to capture the real, lived experiences of practitioners working most intimately with these issues. All data were gathered at Uganda Christian University in Mukono, Uganda, and reflect both the personal and professional accounts of health care professionals living and working throughout communities within these countries.
 	The findings of this study indicate that for as long as poor water and sanitation access and hygiene practices continue to plague the development of women in urban and rural communities, women and pregnant women will continue to suffer from dangerous diseases and brutal attacks of violence. Honing in on the latter concept, this study uncovered a significant link between inadequate water access and rates of domestic violence, sexual assault, and animal attacks.
	Understanding the health professional perspective is crucial in gathering relevant data. Through this effort, the findings of this study have been informed by those most knowledgeable on the WaSH realities identified and therefore has the ability to influence both policy and programs in realistic and productive ways. With the goal of determining and then diminishing identified risks, the data gathered from this research are meant to be used as evidence to help empower and advance women throughout East Africa.

abstract: Thesis

abstract: Master of Social Work (MSW)


title: The Radiosensitivity of Haploid and Diploid Oedogonium Cardiacum and Studies on the Synchrony of Oedogonium Cardiacum

contributor:
Horsley, R. J.
Mak, S.
Biology

subject: radiosensitivity, haploid, diploid, synchrony, inhibitor, chromosome

abstract:
 The ɣ-radiosensitivity of haploid and diploid Oedogonium cardiacum cells was measured and compared to other cell lines. With the doubling of the chromosome complement, the Do value doubled, but the extrapolation number decreased four-fold. A general conclusion was drawn from the results that at all doses of ɣ-radiation, the diploids were more resistant than the haploids. A new radiation technique was used and compared to that used routinely in the laboratory. The further use of the technique was not recommended since the data obtained with the diploid line only was not as reliable as one would like.

 The degree of synchrony of Oe. cardiacum zoospore cultures was measured using cell division as the biological end-point and a mathematical expression, the percent phasing, as the index of synchrony. It was intended that this research problem be secondary to the radiation studies. The percent phasing values were determined for cells growing in two inorganic media and in the presence of an inhibitor, hydroxyurea. However the degree of synchrony was not improved beyond that of the routine laboratory procedure. Attempts to improve the size of the synchronous populations collected also proved unsuccessful.

abstract: Thesis

abstract: Master of Science (MSc)


title: OCT4 Facilitated Alteration of Human Cell Fate

contributor:
Bhatia, Mickie
Biochemistry and Biomedical Sciences

subject: Reprogramming

abstract:
OCT4 is one of four transcription factors known to induce pluripotency when expressed together in somatic cells. However, brief expression of these pluripotency inducing factors in somatic skin fibroblasts followed by treatment with lineage specific culture conditions results in direct conversion towards alternative lineage specific cell types. Our group has previously shown that expression of OCT4 alone in adult human fibroblasts followed by treatment with hematopoietic supportive conditions resulted in the generation of multi-potent blood progenitors without transitioning through a pluripotent intermediate. Despite never having been associated with transcriptional regulation within the hematopoietic compartment, expression of OCT4 induced expression of hematopoietic factors in skin fibroblasts. As such, I hypothesized that ectopic expression of OCT4 in human somatic cells can induce changes in transcription that bestow the potential to make cell fate choices in response to external stimuli.
In direct support of this notion, we revealed that expression of OCT4 in adult human fibroblasts, followed by culturing in neural supportive conditions resulted in the generation of tri-potent neural progenitors, suggesting the effects of OCT4 were not specific or limited to activation of hematopoietic programs. In an effort to understand how OCT4 bestows the potential to make cell fate choices, we assessed the individual vs combined impact of OCT4 and the extracellular environment on transcription during direct conversion of fibroblasts to both blood and neural progenitors. In doing so, we have started to define an induced state of transcriptional activity that is distinct from cells transitioning to pluripotency, and instead characterized by expression related to lineage
iii
PhD Thesis – RR Mitchell McMaster University - Biochemistry
development that is responsive to changes in the extracellular environment that we have termed OCT4 induced plasticity (OiP). Moreover, we revealed that OCT4 mediated direct conversion can facilitate the reprogramming of hematopoietic progenitor cells towards neural progenitor cells, suggesting that this cellular reprogramming approach is not limited to the use of differentiated fibroblasts. In summary, this thesis expands our current knowledge on both the use and understanding of OCT4 as a facilitator of cellular reprogramming in human somatic cells.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Investigations into the Dynamic Behaviour of a Full Scale Municipal Activated Sludge Waste Water Treatment Plant

contributor:
Murphy, K. L.
MacGregor, J.
Chemical Engineering

subject: municipal, sludge, waste water, treatment, plant, hydraulic

abstract: Although both steady state and dynamic simulation studies of the activated sludge process are available, the data bases employed have traditionally been: derived from bench scale studies, derived from historical monitoring data, synthetic based on mathematical functions. Actual plant operating data, if available, would reflect full scale operation and would provide a much better data base to judge existing or future process models. This study was designed to provide a more comprehensive data base than presently existed on a full scale municipal activated sludge system. Both flow and component concentrations were continuously measured on two hour intervals for two periods of 10 days and 5 days duration. Streams sampled included the plant influent, the primary clarifier effluent, the aeration tank effluent, the secondary clarifier effluent, the activated sludge recycle and the waste sludge line. Based on total nitrogen and total phosphorus, the data were examined for mass flow closure around the aeration tank. A time dependent mixing model based on two unequal volume stirred tank reactors in series was found to adequately describe the observed variation in aeration tank input-output data. The measured aeration tank inflow and outflow was corrected to give a hydraulic balance using a statistical procedure which generates flow corrections based on expected measurement error. The resulting total nitrogen and total phosphorus material balances were found to improve based on a reduction of the residual sum of squares.

abstract: Thesis

abstract: Master of Engineering (MEngr)


title: Modelling the Spread of the Human Papillomavirus on the Cervix

contributor:
Dushoff, Jonathan
Mathematics

subject:
mathematical modelling
virus dynamics
HPV
human papillomavirus
cervix
cervical cancer

abstract: Cervical cancer is the fourth most common cancer in women. It is caused by the hu- man papillomavirus (HPV). There are many different types of HPV, some of which are high-risk, highly associated with cancer, and low-risk. While HPV is very common— most sexually active individuals will contract some sexually transmitted HPV infec- tion in their lifetime—most infections are cleared without any complication. However, persistent infections may establish and develop into cancerous lesions. Two vaccines have been developed against the two most high-risk types, and have shown high lev- els of efficacy thus far. However, infections are still occurring and it is not clear why some individuals develop persistent infections while others do not. In this thesis, we develop a model to describe how the infection spreads within the host. We express the basic reproduction number R0, a threshold for the establishment of an infection. We solve for the diseased equilibrium, providing insight about whether an infection will persist or not. We develop a spatial model to examine how spatiality of the infec- tion process affects the establishment or clearance. Lastly, we develop a multi-type HPV model to examine whether competitive HPV types are able to coexist in the host for different levels of competition. Ultimately, this work provides groundwork for within-host modelling of HPV and can provide direction for future research.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: The human papillomavirus (HPV) is a sexually transmitted infection that is known to cause cervical cancer in women along with other genital cancers. Cervical cancer is the fourth most common cancer in women, and thus researchers are looking to reduce the number of cervical cancer cases and the number of HPV infections. In order for HPV to cause cervical cancer, the infection must persist for a long time. Most individuals clear the infection without any complication; however, some individuals develop persistent infections. By using mathematical and computation models, we hope to understand why and how HPV infections spread in the host. We develop a criterion for when the infection may be able to establish in the host, and explore conditions that could lead to clearance. Understanding when and how infections will persist could inform treatment and monitoring of cervical cancer development.


title: Circulating Endothelial and Progenitor Cells in Healthy Children and Children with Juvenile Idiopathic Arthritis: Role of Fitness, Physical Activity, and Acute Exercise

title: Circulating Endothelial and Progenitor Cells in Children

contributor:
Timmons, Brian W.
Kinesiology

subject:
children
exercise physiology
flow cytometry
accelerometry
juvenile idiopathic arthritis
fitness
cardiovascular health

abstract:
Circulating endothelial cells (CECs) and endothelial progenitor cells (EPCs) are sensitive markers of cardiovascular damage and repair, respectively. The aim of this thesis was to advance the state of knowledge regarding CECs and EPCs, and the factors affecting their concentrations, in children and adolescents.
	The first and second studies demonstrated that CECs and EPCs were similar when participants were split by sex, chronological age (8-10 vs. 14-16 years), and biological age (≤ -1 vs. ≥ +1 year from peak height velocity). Moreover, CECs, but not EPCs, were positively associated with aerobic fitness and negatively related to daily moderate-to-vigorous physical activity.  Neither CECs nor EPCs were related to level of adiposity. Although there was a large degree of inter-individual variability in both cell types, most of our data were clustered towards one end of the reported range. These observations highlighted the need to examine these cells in children with chronic conditions associated with an increased risk of poor cardiovascular health. Therefore, CECs and EPCs were examined at rest and in response to acute exercise in juvenile idiopathic arthritis (JIA) and healthy controls. Resting levels of CECs and EPCs were similar in both groups, which may be attributable to the low disease activity in the participants with JIA. High intensity, intermittent exercise (HIIE) and moderate intensity, continuous exercise (MICE) had no effect on CECs in both groups. Conversely, MICE led to a robust increase in EPCs in healthy controls; no such change was observed in youth with JIA.
	This thesis represents the first comprehensive assessment of CECs and EPCs in the context of fitness, physical activity, and acute exercise in children and adolescents. Future research should examine the function and fate of these cells in youth, as well as the potential mechanisms underlying the blunted EPC response to exercise in JIA.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: Fitness and physical activity are critical for maintaining and improving cardiovascular health in children and adults. We don’t know exactly how they do this but the evidence in adults suggests it may be related to rare cells in the blood involved in repairing damaged blood vessels. The main objective of this thesis was to learn more about these cells, called circulating endothelial cells and endothelial progenitor cells, in children. We found that only circulating endothelial cells were related to fitness and physical activity. We also found that endothelial progenitor cells increased when healthy children performed 60 minutes of cycling. On the other hand, these cells did not change when children with juvenile idiopathic arthritis performed the same exercise. More research is needed to determine exactly why these cells responded to exercise in healthy but not sick children, and to help us identify the optimal exercise to improve these cells in youth.


title: The Voices of the Youth: How Indigenous Young People Experience Plans of Care

contributor:
Freeman, Bonnie
Social Work

subject: Indigenous, Aboriginal, First Nations, youth, child welfare, plans of care

abstract:
Indigenous people in Canada have suffered through immense trauma since colonization, and child welfare agencies have contributed to the assimilation of Indigenous children. This research explores the stories of Indigenous people who have been in the care of Children’s Aid Society in Ontario and how they have experienced their plan of care. Every child in the child welfare system has a plan of care completed by their worker at regular intervals. This document is intended to review the child’s progress in various dimensions of their lives and facilitate goal-setting for the future. The plan of care is a standardized document that is created from a Western perspective and thus does not necessarily reflect Indigenous culture or the child’s true self. Using a mixed methods approach with a strong emphasis on Indigenous Methodologies, two Indigenous young adults shared their stories about their experiences with plans of care. In addition, an Indigenous key informant provided context from an Indigenous perspective on how plans of care can be improved for Indigenous children in care. To understand the plan of care document from a child/youth’s perspective, the author of this research asked a co-worker to complete a plan of care on their life. A critique of this experience is shared in this study.
	Findings suggest that experiences with plans of care can vary significantly, and depend greatly on the relationship between the young person and their child welfare worker. The two Indigenous young adults valued participation in their plan of care and found the goal setting to be useful when they were consulted. However, it is determined that the child welfare worker can bring Indigenous culture into the document in creative ways. These findings lead to recommendations for change at the micro and macro levels involving greater opportunities for relationship-building, space for young people to participate, and including Indigenous knowledge in child welfare practice.

abstract: Thesis

abstract: Master of Social Work (MSW)


title: Demons in the Theology of Augustine

contributor:
Kroeker, P. Travis
Religious Studies

subject:
Augustine
Demons and Demonology
Theology

abstract: This thesis gives an account of Augustine’s understanding of demons, a full-length study of which has yet to be published. I argue that the scriptural assertion that pagan gods are demons fully encompasses what demons are for Augustine, and I proceed by elucidating the theology with which he contextualizes this assertion and makes it intelligible. Demons emerge as a highly integrated component of Augustine’s broader theology, having not a merely conceptual but a fully religious significance. The dissertation begins with the intellectual nature of the angels and their Christocentric mission to reveal God in creation. The second chapter considers the fall of the angels and Augustine’s questions about its cause and the timeline of its occurrence. These questions pertain to the matter of embodiment, which becomes the starting point for Chapter 3, where we discuss the demons’ putative aerial bodies, their appearance in bodily visions, and some of Augustine’s reports of wondrous demonic phenomena. These phenomena are identified together as demonic not by a common aerial nature but a common meaning. Chapter 4 begins our analysis of what is the most significant demonic phenomenon for Augustine, viz. pagan religion. There we give an account of Augustine’s notion of the devil’s body, which, like its counterpart in the body of Christ, is constituted by sacraments, whose production is best described in terms of Hermetic “god-making.” The last chapter examines Augustine’s account of pagan sacramental theology more specifically, in terms of both a more straightforward understanding of pagan religion, and the more philosophical one offered by the Platonists. The demons’ association with pagan religion represents the full inversion of the angels’ Christocentric ministry, such that the only true freedom from demons is found, according to Augustine, through incorporation into the sacramental life of the church.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)

abstract: This thesis gives an account of Augustine’s understanding of demons. Christian Scriptures declare that pagan gods are demons, and I argue this fully encompasses what demons are for Augustine, as they have not a merely conceptual but a fully religious significance. This study explores the theology with which he contextualizes this assertion and makes it intelligible. Demons are a highly integrated component of Augustine’s broader theology, rooted in his conception of angels as the ministers of all creation under God. They take shape through Augustine’s doctrine of evil as privation and understanding of the fall, his thoughts on embodiment, desire, and visions, as well as his theology of sacraments and social bodies. The demons’ association with pagan religion represents the full inversion of the angels’ Christocentric ministry, such that, for Augustine, the only true freedom from demons is found through incorporation into the sacramental life of the church.


title: Song Popularity as a Contagious Process in Great Britain

contributor:
Earn, David J.D.
Mathematics and Statistics

abstract: Determining the mechanisms by which a song becomes popular is a complex problem. The rapidity with which some songs gain popularity often leads to them being described as 'contagious' or 'infectious'. Upon closer examination, we find that the download time series for many popular songs do resemble epidemic curves derived from case report data for infectious diseases. This correspondence suggests an interesting link between the fields of infectious disease research and music research: perhaps ideas from epidemiological modelling might be useful in investigating how certain songs 'spread' through human populations, and perhaps employing disease epidemic models might help to better understand the mechanisms underlying song popularity. Download data were obtained from MixRadio based on song downloads through Nokia cell phones in Great Britain over a seven year period and aggregated at various timescales. Songs were characterized by fitting a standard epidemic model to song download time series. The fits estimate standard epidemiological parameter values for each song, providing new insights about popularity of music. In addition, we propose and analyze a new model that is better suited to 'song transmission' and comment on how this model might be used to study song popularity in the future.

abstract: Thesis

abstract: Master of Science (MSc)


title: Physiological and health-related adaptations to low-volume interval exercise training in humans

contributor:
Gibala, Martin
Kinesiology

subject:
exercise
interval training
cardiometabolic health
insulin sensitivity
skeletal muscle
mitochondria
physiology

abstract: This thesis sought to advance our understanding of the physiological and health-related adaptations to low-volume interval training. Three separate studies were conducted in previously sedentary adults who trained three times per week. High-intensity interval training (HIIT) involved ten, 60-second cycling efforts at an intensity that elicited ~90% of maximal heart rate, interspersed with 60 seconds of recovery, whereas sprint interval training (SIT) involved three, 20-second ‘all-out’ cycling efforts interspersed with 2 minutes of recovery. Both protocols involved a brief warm-up and cool-down, resulting in 25- and 10-minute sessions for HIIT and SIT, respectively. Peak oxygen uptake (VO2peak), skeletal muscle mitochondrial content as reflected by the maximal activity and protein content of mitochondrial enzymes, and glycemic control based on oral glucose tolerance tests (OGTTs), intravenous glucose tolerance tests (IVGTTs) or continuous glucose monitoring (CGM), were determined before and after training. Study 1 found that 6 weeks of HIIT in the fed or fasted state increased VO2peak and mitochondrial content in women, but insulin sensitivity based on OGTTs was unchanged. Study 2 showed that 6 weeks of SIT increased VO2peak and mitochondrial content in men and women, whereas mean 24-hour glucose based on CGM was reduced in men only. Study 3 directly compared 12 weeks of SIT to traditional moderate-intensity continuous training (MICT) in men. The two protocols elicited similar improvements in VO2peak, mitochondrial content and insulin sensitivity based on IVGTTs, despite SIT involving a five-fold lower exercise volume and time commitment. This work advances our understanding of the potency of brief, intense exercise training to induce physiological remodeling and improve cardiometabolic health. It also highlights potential sex-specific adaptations to interval training that warrant clarification. Further investigation into the mechanisms of physiological remodeling to HIIT and SIT is needed, as are large-scale randomized clinical trials that compare these protocols to MICT.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: This thesis examined physiological and health-related adaptations to interval training, which involves brief bouts of intense exercise interspersed with recovery periods. One protocol involved alternating 60-second hard and easy cycling efforts for 20 minutes; the other involved three, 20-second ‘all-out’ sprints interspersed with 2 minutes of recovery. Both protocols improved indices of cardiometabolic health in previously inactive adults who trained three times per week for 6 weeks, even though the amount of exercise performed was lower than typically recommended in public health guidelines. When the latter protocol was directly compared against traditional endurance training, the improvement in cardiometabolic health after 12 weeks was the same, despite a five-fold difference in the total amount of exercise performed. Our findings highlight the effectiveness of short bursts of high-intensity exercise for improving health. These results may appeal to individuals who cite “lack of time” as a barrier to exercise.


title: Tuning for the rate and duration of frequency modulated sweeps in the inferior colliculus of the big brown bat

contributor:
Faure, Paul
Psychology

abstract: I investigated how the auditory system encodes frequency modulated (FM) sweeps, by recording neuronal responses in the auditory midbrain (inferior colliculus, IC) of the big brown bat, (Eptesicus fuscus) while searching for the responses of so-called “FM duration-tuned neurons (DTNs)”. The responses of DTNs are selective for stimulus duration. My project investigated how the responses of FM DTNs encode the two temporal properties of FM sweeps: sweep duration, and the rate of frequency change (i.e. sweep rate). Based on previous studies, it was unclear whether FM DTNs were tuned to signal duration like classic DTNs, or simply the rate of FM. I addressed this question using single unit extracellular recordings from DTNs in the IC of E. fuscus. First, I measured the spectral tuning parameters of a cell, and then FM pulses were randomly varied in duration to measure the temporal bandwidth of duration tuning of the cell. To separate FM rate tuning from duration tuning, the duration tuning of the cells was tested at different sweep bandwidths (i.e. doubled or halved) while keeping the center frequency constant. If a neuron is tuned to stimulus duration, then the range of excitatory signal duration(s) should not change with changes in FM bandwidth; however, if the cell is tuned to the rate of FM, then the range of excitatory durations should corresponed to the same FM rate of each altered bandwidth. A Bayesian model comparison showed that an overwhelming majority of FM DTNs were in fact tuned to sweep rate. Thus, I conclude that the dominant response parameter for temporal tuning of FM cells in the IC of the bat is not signal duration, but FM sweep rate.

abstract: Thesis

abstract: Master of Science (MSc)


title: Fetal and neonatal exposure to nicotine results in increased adiposity: role of the gut microbiome

contributor: Medical Sciences (Division of Physiology/Pharmacology)

subject: Microbiome Nicotine pregnancy

abstract:
Introduction: Maternal smoking is a risk factor for childhood overweight and obesity. However, the mechanisms underlying this association are largely unknown. Smoking is associated with changes in the composition of the maternal microbiome and there is now considerable evidence to suggest that the infant microbiome may play an important role in the development of obesity. Therefore we hypothesized that fetal and neonatal exposure to nicotine, the major addictive component of cigarettes, would result in dysbiosis, an alteration in the composition of the microbiome, in postnatal life.
Methods: Nulliparous female Wistar rats were randomized to receive daily injections of saline (N=20) or nicotine bitartate (1.0 mg/kg/d; N=20) from 2 weeks prior to mating until weaning. We assessed markers of inflammation, gut permeability, and the composition of the gut microbiota in the offspring.
Results: At the phyla level, exposure to nicotine resulted in alterations in the proportion of both Firmicutes and Bacteriodetes at 26 weeks of age.  There were significant changes in a number of operational taxonomic units (OTUs) at 3, 12 and 26 weeks of age. Of note, a number of OTUs for Firmicute Clostridia Clostridiales Lachnospiraceae and Firmicute Clostridia Clostridiales Ruminococcus were decreased in the nicotine-exposed offspring which may suggest increased energy extraction in these animals. Although there was evidence of altered gene expression in pathways regulating inflammation and development, these did not result in increased inflammation or aberrant gut development
Conclusion: Maternal nicotine-exposure resulted in dysbiosis in the gut of the offspring; an effect that persisted into adulthood.  Since dysbiosis has been associated with increased weight gain and adiposity, these data suggest that alterations in the gut microbiome as a result of maternal nicotine-exposure may explain, in part, the increased risk of obesity in children born to mothers who smoke.

abstract: Thesis

abstract: Master of Health Sciences (MSc)


title: Three Essays in Health Economics

contributor:
Hurley, Jeremiah
Economics

abstract: This thesis comprises three essays that empirically explore two important areas in health economics and policy: the valuation of medical innovations, and access to healthcare. The first essay explores the role of new medical technologies in improving labor market outcomes by conducting a case study of a class of drugs used in the treatment of arthritis called Cox-2 inhibitors. Cox-2 drugs make an excellent case study for investigating the labor supply effects of medical innovation because the potential labor supply effects are large, and the market introduction of these drugs generates plausibly exogenous variation in their use. Using data from the Health and Retirement Study (HRS) and applying a difference-in-differences approach that compares individuals with arthritis to individuals without arthritis, I find that the introduction of Cox-2 drugs had a positive and significant impact on the probability of working among individuals with long-term arthritis. The effects are stronger among older individuals, the less-educated, and those working in physical occupations. These results highlight the importance of evaluating economic outcomes such as labor supply as part of an assessment of the overall benefits of medical technology. The second essay builds on work by Allin et al. (2010) and Hurley et al. (2011) that systematically analyzes the relationship between subjective unmet need and healthcare utilization. However, unlike previous work that uses cross-sectional data, I use panel data from the National Population Health Survey (NPHS) to control for fixed unobserved individual heterogeneity. In addition, healthcare utilization is modeled using latent class models for panel data, which outperform traditional hurdle models. The results of this study confirm previous findings of different patterns of healthcare utilization among individuals with system-related unmet needs, personal-related unmet needs, and no unmet needs. Individuals with personal-related unmet needs tended to use the same amount of services as expected based on their needs. On the other hand, individuals with system-related unmet needs were found to not only be high users of GP and specialist visits, they were also higher-than-expected users. The third essay examines long-term changes in socioeconomic inequality and inequity in influenza immunization in Canada. The concentration index framework is applied using data from the following two Statistics Canada surveys: the cross-sectional component of the 1996/97 National Population Health Survey (NPHS), and the 2007/08 Canadian Community Health Survey (CCHS). The results show large variations in both coverage and inequity across provinces. In addition, increases in coverage levels across many provinces seem to have drawn disproportionately from those of higher socioeconomic status, contributing to a growing pro-rich inequity in utilization. These results highlight the need for more targeted efforts to help reduce inequities in vaccination.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Quality Fairness-oriented Cross-layer Resource Allocation for Scalable Video Delivery over OFDMA Wireless Networks

contributor:
Dumitrescu, Sorina
Electrical and Computer Engineering

abstract:
This thesis addresses the problem of scalable video delivery to multiple users over
OFDMA wireless networks, where quality fairness and system e ciency are jointly
considered. Fairness deals with the provision of a similar video quality to all users,
while system e ciency concerns the maximization of the overall received video quality.
This problem was recently tackled by Cical o and Tralli who proposed a cross-layer
optimization framework with the aim of maximizing the sum of the ergodic rates while
minimizing the distortion di erence among multiple videos. The optimization problem
was \vertically" decomposed into two subproblems: a source adaptation problem
at the application (APP) layer and a resource allocation problem at the medium
access control (MAC) layer. An iterative local approximation (ILA) algorithm was
proposed to solve the two subproblems iteratively until the optimal solution is obtained.
One drawback of the above work is that the APP layer algorithm to solve the
source adaptation problem is unnecessarily complex. Moreover, the optimal solution
may not be accurate since the adopted semi-analytical rate-distortion (R-D) model
used for source adaptation is only an approximation of the empirical R-D data.
Our  rst main contribution is to overcome the aforementioned two drawbacks.
To this end, we propose a quality fairness-oriented cross-layer optimization framework
that solves a joint resource allocation and source adaptation (JRASA) problem where the objective is to maximize the sum of the PSNRs while minimizing the PSNR
di erence among the received videos. The JRASA problem is equivalent to the aforementioned
sum-rate maximization problem and capable of being solved by the ILA
approach. On the other hand, it has a di erent formulation which naturally leads
to the development of a considerably faster APP layer algorithm based on the bisection
search method. Furthermore, we show that the above optimization framework
can be extended to solve e ciently the JRASA problem based on accurate empirical
R-D models, as well. The solution to the JRASA problem using the empirical R-D
models can be used as a benchmark to assess the performance of solutions based on
approximate R-D models, such as the semi-analytical R-D model.
Our second main contribution is an adjustable quality-fair cross-layer optimization
framework, which is able to achieve trade-o s between quality fairness and system
e ciency, aspect which was not considered by Cical o and Tralli. Our procedure
consists of two steps. First the aforementioned JRASA problem is solved. The second
step seeks to maximize the sum of the PSNRs while limiting the absolute value of
the relative di erence between the PSNR of each video and the common PSNR value
obtained in the  rst step. We show that the second problem is a general utility-based
resource allocation problem, for which e cient algorithms are available to obtain an
almost surely optimal solution.
Numerical results show that the proposed quality-fair optimization framework
provides signi cantly better performance in terms of quality fairness and the provision
of better quality to high-complexity videos with respect to an equal-rate adaptation
scheme. Moreover, various trade-o s between fairness and system e ciency can be
achieved using the adjustable quality-fair cross-layer optimization framework.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Structural Studies of Some Dimeric Complexes of Rhenium

contributor:
Lock, C. J. L.
Chemistry

subject: crystal, structures, rhenium, complexes, diffraction, dimeric

abstract:
 The crystal structures of three complexes of rhenium have been determined by single crystal x-ray diffraction methods. The structure and the probable position of the hydrogen atom in the complex tetracarbonyl-rhenium(I)-μ-oxo-μ-hydroxotetracarbonylrhenate(I) are discussed.

 The structural results for the other two complexes show the presence of carboxylato-bridged dinuclear rhenium core. The very short rhenium to rhenium distances and the eclipsed rotomeric configurations are similar to those found in octachlorodirhenate(III) anion. A reaction scheme for the formation of these complexes from rhenium(III) chloride is postulated and correlated with the structural results. The nature of bonding in the carboxylato complexes of rhenium is discussed.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: The Time-Concentration Relationship of Trace Metals in the Growth of Algae

contributor:
Kramer, J. R.
Geology

subject: time, concentration, trace, metals, growth, algae

abstract:
 The time relationship of metabolically important trace metals (Fe, Cu, Zn, Co, Cd, Cr) in Lake Erie plankton were analyzed from samples collected during an algal (Aphanizomenon) bloom. Iron and cobalt showed a rapid increase in concentretion during the initial period of the bloom, followed by a decrease and levelling off to an equilibrium value. Copper and zinc were found to behave similarily undergoing a slight decrease at the beginning and then steadily increasing in concentration with time. Different depths of sampling were correlated to the life-death cycle of the organism and specific metal concentration trends. Algae from the lowest level of sampling (9.7 m; dead organism level) exhibited an increasing nutrient concentration (Fe, Zn, Co, and PO4) with time.

 Factor analysis suggested a Fe, Co, depth, 1/Biomass relationship; a Cu, Zn relationship; and a PO4, time relationship. The first two were verified from the experimental results; the last was not.

abstract: Thesis

abstract: Bachelor of Science (BSc)


title: The Semiclassical Approximation and Strutinsky Smoothing

contributor:
Bhaduri, R. K.
Physics

subject: semiclassical, approximation, density, Strutinsky, smoothing

abstract:
 An expression for the semiclassical density of states for a particle in a smooth potential well is obtained from the Kirkwood expansion of the partition function. This expression for the semiclassical density of states is then shown to be essentially equivalent to the expression obtained from the Green's function method of Balian and Bloch.

 The Strutinsky shell correction to the nuclear binding energy is then analytically shown to be equivalent to the shell correction obtained from a consideration of the semiclassical partition function if certain restrictions on the Strutinsky smoothing parameter can be met.

abstract: Thesis

abstract: Master of Science (MSc)


title: Some Applications of Fibre Bundle Techniques in Physics

contributor:
Ihrig, E.
Physics

subject: differential, fibre, bundles, structure, relativity, symplectic

abstract: Both the theories of differential geometry and of Lie groups and their algebras have been invaluable to the physicist. In the theory of fibre bundles and in the symplectic formulation of mechanics, these fields coalesce to provide a rich structure that enables her/him to obtain a more unified overview of the modern theories in physics. In this short work, we introduce this structure and examine its consequences in general relativity and quantum mechanics.

abstract: Thesis

abstract: Master of Science (MSc)


title: The Effects of Somatosensory Afference on Corticospinal Excitability in Uninjured and Spinal Cord Injured Individuals

contributor:
Nelson, Aimee
Kinesiology

subject:
spinal cord injury
afferent
motor cortex
somatosensory cortex
short-latency afferent inhibition

abstract: Primary somatosensory cortex (SI) is an important cortical structure involved in receiving and relaying sensory inputs to condition primary motor cortex (M1). The functional interaction between SI and M1 is important for motor control by providing surround inhibition, which is the inhibition of muscles not involved in the movement and in learning new motor skills. This interconnection is known as short-latency afferent inhibition (SAI) and may be probed using Transcranial magnetic stimulation and peripheral nerve stimulation. SAI is dependent on the afferent volley as increasing the nerve stimulation intensity increases the depth of SAI. Individuals with spinal cord injury show reductions in SAI evoked in lower limb and this may be a contributing factor to the impairments in motor control seen within this population. SAI has yet to be investigated in the upper limb in individuals with chronic cervical SCI and this thesis examines these alterations. Two experiments were performed examining M1 excitability (motor evoked potentials), SI excitability (somatosensory evoked potentials) and the interconnection between SI and M1 (SAI). The first Experiment investigated alterations in these measures in individuals with SCI while the second Experiment investigated these measures as a function of the afferent volley. The collective results from Experiment 1 indicate that motor evoked potentials and SAI are reduced but somatosensory evoked potentials are similar to controls. Further data from Experiment 2 indicate that SAI and SEPs increase as a function of the afferent volley and indicate that alterations seen in individuals with SCI may be due to cortical plasticity in the synapses from SI to M1 or within M1. The novel findings of this thesis have indicated aberrant cortical circuits in individuals with SCI and have indicated potential synapses that may be targets for TMS plasticity protocols to alter and restore function to these circuits.

abstract: Thesis

abstract: Master of Science (MSc)


title: FUEL COMPOSITION TRANSIENTS IN SOLID OXIDE FUEL CELL GAS TURBINE HYBRID SYSTEMS FOR POLYGENERATION APPLICATIONS

contributor:
Adams II, Thomas A.
Chemical Engineering

subject:
solid oxide fuel cell
gas turbine hybrid system
fuel flexibility
dynamic characterization
hardware-based simulations
fuel composition transients
coupling effects
cathode air mass flow

abstract:
The potential of Solid Oxide Fuel Cell Gas Turbine (SOFC/GT) hybrid systems for fuel flexibility makes this technology greatly attractive for system hybridization with various fuel processing units in advanced power generation systems and/or polygeneration plants. Such hybrid technologies open up the possibility and opportunities for improvement of system reliabilities and operabilities. However, SOFC/GT hybrid systems have not yet reached their full potential in term of capitalizing on the synergistic benefits of fuel cell and gas turbine cycles.
Integrating fuel cells with gas turbine and other components for transient operations increases the risk for exposure to rapid and significant changes in process dynamics and performance, which are primarily associated with fuel cell thermal management and compressor surge. This can lead to severe fuel cell failure, shaft overspeed, and gas turbine damage. Sufficient dynamic control architectures should be made to mitigate undesirable dynamic behaviours and/or system constraint violations before this technology can be commercialized. But, adequate understanding about dynamic coupling interactions between system components in the hybrid configuration is essential.
Considering this critical need for system identification of SOFC/GT hybrid in fuel flexible systems, this thesis investigates the dynamic performance of SOFC/GT hybrid technology in response to fuel composition changes. Hardware-based simulations, which combined actual equipment of direct-fired recuperated gas turbine system and simulated fuel cell subsystem, are used to experimentally investigate the impacts of fuel composition changes on the SOFC/GT hybrid system, reducing potentially large inaccuracies in the dynamic study.
	The impacts of fuel composition in a closed loop operation using turbine speed control were first studied for the purpose of simplicity. Quantification of safe operating conditions for dynamic operations associated with carbon deposition and compressor stall and surge was done prior to the execution of experimentation. With closed loop tests, the dynamic performance of SOFC/GT hybrid technology due to a transition in gas composition could be uniquely characterized, eliminating the interactive effects of other process variables and disturbances. However, for an extensive system analysis, open loop tests (without turbine speed control) were also conducted such that potential coupling impacts exhibited by the SOFC/GT hybrid during fuel transients could be explored. Detailed characterization of SOFC/GT dynamic performance was performed to identify the interrelationship of each fuel cell variable in response to fuel composition dynamics and their contributions to operability of the system.
	As a result of lowering LHV content in the fuel feed, which involved a transition from coal-derived syngas to humidified methane composition in the SOFC anode, the system demonstrated a dramatic transient increase in fuel cell thermal effluent with a time scale of seconds, resulting from the conversion of fuel cell thermal energy storage into chemical energy.  This transient was highly associated with the dynamics of solid and gas temperatures, heat flux, heat generation in the fuel cell due to perturbations in methane reforming, water-gas shifting, and electrochemical hydrogen oxidation.
	In turn, the dramatic changes in fuel cell thermal effluent resulting from the anode composition changes drove the turbine transients that caused significant cathode airflow fluctuations.  This study revealed that the cathode air mass flow change was a major linking event during fuel composition changes in the SOFC/GT hybrid system. Both transients in cathode air mass flow and anode composition significantly affected the hybrid system performance. Due to significant coupling between fuel composition transitions and cathode air mass flow changes, thermal management of SOFC/GT hybrid systems might be challenging. Yet, it was suggested that modulating cathode air flow offered promise for effective dynamic control of SOFC/GT hybrid systems with fuel flexibility.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Digital Control Studies of a Liquid-Liquid Extraction Column Using a Minicomputer

subject: digital, liquid-liquid, extraction, minicomputer, control

abstract:
 This report covers two topics. First is the development of computer programs to carry out the calculations needed to determine the control policy to bring a process from one set of steady state conditions to another. Examples of the implementation of control policies for a liquid-liquid extraction column are included. Suggestions have been made for means of decreasing the calculation time and for means of increasing the size of problem that may be solved.

 The second part discusses an initial project of using a Supernova computer as a direct control computer. Characteristics of direct digital control are illustrated using an analog simulation of the extraction unit as the controlled process.

abstract: Thesis

abstract: Master of Engineering (MEngr)


title: Informing the design of an age of blood crossover randomized controlled trial in patients with Myelodysplastic syndromes to study change in quality of life as a response to RBC transfusion

contributor:
Heddle, Nancy M.
Health Research Methodology

subject:
Age of Blood
Myelodysplastic Syndrome
Quality of Life
Chart Review
Qualitative
Systematic Review

abstract:
Patients with myelodysplastic syndromes (MDS) frequently receive red blood cell (RBC) transfusions to alleviate symptoms of anemia and improve health-related quality of life (HR-QoL). Patients can sometimes continue to feel unwell after transfusion and the age of the transfused RBCs could contribute to this observation. Three pilot studies were conducted to inform the design of a randomized crossover trial to determine if fresh blood to MDS patients could improve HR-QoL post-transfusion.
A systematic review was performed to inform the background and rationale for the trial. The results showed a dearth of literature addressing the research question. Only two clinical trials have been conducted to date where fatigue and HR-QoL were the primary outcomes of interest. Although results of the trials were negative, several limitations and generalizability issues warrant additional research in this area.
Crossover designs necessitate patients have a stable prognosis while being observed; hence, a chart review of adult MDS patients was conducted to assess clinical stability using the following criteria: interval of days between transfusions; pre-transfusion Hb; number of hospital admissions; and severe infections. Results indicated that the majority of patients who had received greater than 3 transfusions within the 6-month observation period had stable disease and were appropriate for a crossover trial. The criteria defining stability will be useful for identifying eligible patients.
Finally, an applied qualitative study in adult MDS patients in Hamilton was conducted to inform the selection of an appropriate outcome measure (i.e. HR- QoL tool). Short semi-structured interviews were conducted with participants to elicit information about anemia related symptoms and changes in well-being in response to transfusion. The results of the study support clinical observations that suggest patients do not immediately recover post-transfusion. Findings indicate that an appropriate HR-QoL tool should be short, be disease specific, and have a short recall period. Currently, the Quality of Life-E tool, validated in patients with MDS, fits most of these criteria.
In conclusion, data from the systematic review and the two pilot studies suggest that it may be feasible to conduct an age of blood crossover trial in MDS patients where the primary outcome of interest is HR-QoL.

abstract: Thesis

abstract: Master of Science (MSc)


title: An Electronically-switched Sensor Array for Microwave Imaging

contributor:
Nikolova, Natalia
Electrical and Computer Engineering

subject: microwave imaging cancer breast array antennas

abstract: An array of electronically-switched circular patch antennas is designed for breast tissue imaging for the purposes of cancer screening. Each array element is connected to a dedicated heterodyne radio, which performs amplification and downconversion to a single, low intermediate frequency for improved signal recovery. Data acquisition is accomplished with a VNA-based architecture. Details of the design are provided and are accompanied by simulated and experimental data. A receiver sensitivity of at least -120 dBm is expected, and an imaging sensor switching dynamic range between ON and OFF states of at least 127 dB is demonstrated based on experimental measurements.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: CROSS-CULTURAL ADAPTATION OF THE PARTICIPATION AND ENVIRONMENT MEASURE FOR CHILDREN AND YOUTH IN THE KOREAN CULTURAL CONTEXT

title: PARTICIPATION MEASURE FOR KOREAN CHILDREN WITH DISABILITIES

contributor:
Law, Mary
Rehabilitation Science

subject:
participation
environment
measurement
Korean
children with disabilities

abstract: The Participation and Environment Measure for Children and Youth (PEM-CY) is a parent-report measure assessing children’s participation and environmental factors across home, school and community. Although the PEM-CY has demonstrated reliability and validity in North America, no studies have yet reported the psychometric properties of a Korean PEM-CY (KPEM-CY). In order to use the PEM-CY in the Korean cultural context, this research developed the KPEM-CY and tested its reliability and validity in the Korean population. Through a unique cross-cultural adaptation guideline, the KPEM-CY was developed. A total of 76% of the participation items and 29% of the environment items were revised to improve their fit with the Korean culture. To examine internal consistency, test-retest reliability, and known group validity of the KPEM-CY, 196 parents of children (80 children with disabilities) aged 5 to 13 years were recruited in the city of Daejeon, South Korea. Internal consistency was found to be moderate to excellent for the summary scores. Test-retest reliability was excellent for participation frequency and extent of involvement across the three settings and moderate to excellent for the home setting. Significant differences were identified in the specific dimensions of children’s participation and environmental factors according to factors of a child and their parents (i.e., disability, child’s age, and type of school). This thesis provides evidence that the KPEM-CY is a reliable and valid measure for Korean children aged 5 to 13 years. The results of this thesis provide an understanding about Korean children’s participation patterns and the impact of environmental factors on their participation. This new knoweldge can assist occupational therapists to set intervention goals and to conduct future studies to improve the participation of Korean children with disabilities. The KPEM-CY also has the potential to be used in population-level studies to compare children’s participation patterns across regions, countries and cultures.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: The Korean version of the Participation and Environment Measure for Children and Youth (KPEM-CY) was examined for use with Korean children aged 5 to 13 years through two processes. Firstly, the original PEM-CY was cross-culturally translated to Korean based on the different perspectives of various experts working with children with disabilities. Second, the KPEM-CY was tested to determine whether it is a reliable and valid tool to assess the participation of Korean children with disabilities and the environmental supports or barriers to their participation. Through this process, the participation patterns of Korean children with and without disabilities and environmental factors affecting their participation were identified. These results may help occupational therapists plan intervention goals and could provide the basis for future studies of the participation of Korean children with disabilities. The KPEM-CY could also be used in population-level studies to compare children’s participation patterns across regions, countries, and cultures.


title: The Structure and Evolution of Unbound Star-forming Molecular Clouds

contributor:
Sills, Alison
Wadsley, James
Physics and Astronomy

abstract: Recent generations of stars form principally, and possibly exclusively, in giant molecular clouds -- large conglomerations of gas and dust primarily composed of molecular hydrogen and concentrated in the arms of spiral galaxies.  These clouds are assumed to be gravitationally bound; however, recent observations suggest the presence of a substantial population of unbound clouds in the Milky Way.  Using synthetic observations from high-resolution simulations of bound and unbound molecular clouds, we explore whether clouds in this mixed population could match observations of local molecular clouds.  We find from the clouds in our sample that a state of virial equilibrium is not required to form stars and match the dynamics and structure of observed clouds, as described by the Larson scaling relations and the probability distribution function (PDF) of the mass surface density.  As these clouds evolve, the underlying lognormal shape of the column density PDFs is effectively concealed as the peaks of their distributions shift to surface densities below observational detection thresholds, supporting recent observations which also find little to no evidence for a lognormal distribution in column density PDFs of nearby clouds.  We explore these results further in an extragalactic context by simulating molecular clouds formed in a galactic disc, in order to demonstrate the role their environment, particularly the galactic shear, plays on their structure and evolution and on the star formation within them.  We find that a substantial population of unbound molecular clouds forms naturally in a galactic disc environment and demonstrate that their presence not only matches galactic and extragalactic observations but also impacts several long-standing issues in star formation.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Fusion of Soft and Hard Data for Event Prediction and State Estimation

contributor:
Kirubarajan, Thia
Electrical and Computer Engineering

subject: Dempster-Shafer belief theory, Random finite set theory, Modified Dempster's rule of combination, soft and hard data fusion, airborne surveillance of surface targets, event prediction, social data analysis

abstract:
Social networking sites such as Twitter, Facebook and Flickr play an important role
in disseminating breaking news about natural disasters, terrorist attacks and other
events. They serve as sources of  first-hand information to deliver instantaneous news
to the masses, since millions of users visit these sites to post and read news items regularly.
Hence, by exploring e fficient mathematical techniques like Dempster-Shafer
theory and Modi ed Dempster's rule of combination, we can process large amounts of
data from these sites to extract useful information in a timely manner. In surveillance
related applications, the objective of processing voluminous social network data is to
predict events like revolutions and terrorist attacks before they unfold. By fusing the
soft and often unreliable data from these sites with hard and more reliable data from
sensors like radar and the Automatic Identi cation System (AIS), we can improve
our event prediction capability. In this paper, we present a class of algorithms to
fuse hard sensor data with soft social network data (tweets) in an e ffective manner.
Preliminary results using are also presented.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Advanced Magnetic Resonance (MR) Diffusion Analysis in Healthy Human Liver

contributor:
Noseworthy, Michael D.
Medical Physics

subject:
MRI
Diffusion tensor imaging
Liver
Intravoxel incoherent motion imaging

abstract:
Diagnosing diffuse liver disease first involves measurement of blood enzymes followed by biopsy. However, blood markers lack spatial and diagnostic specificity and biopsy is highly risky and variable. Although structural changes have been evaluated using diffusion weighted imaging (DWI), the technique is minimally quantitative.  Quantitative MR diffusion approaches, such as intra-voxel incoherent motion (IVIM) and diffusion tensor imaging (DTI) have been proposed to better characterize diseased liver.  However, the so called pseudo-hepatic artefact due to cardiac motion, drastically affects DWI results.  The overall goals of this thesis were thus to evaluate the pseudo-hepatic anisotropy artefact on the quality of diffusion tensor (DT) and IVIM metrics, and to identify potential solutions.
Intra- and intersession DTI repeatability was evaluated in healthy human livers when varying the number of diffusion encoding gradients (NGD) and number of signal averages (NSA). Although no further advantage was observed with increasing NGD beyond 6 directions, increased NSA improved intra- and inter-session repeatability.  The pseudo-hepatic artefact  resulted in increased fractional anisotropy (FA) and tensor eigenvalues (λ1, λ2, λ3), most prominent in the left liver lobe during systole of the cardiac cycle. Without taking advantage of tensor directional information, increasing the acquired NGD slightly improved IVIM fit quality thus helping to minimize the pseudo-hepatic artefact.  Combining IVIM and DTI resulted in FA values closer to the hypothesized value of 0.0, which, based on liver microstructure is most logical. Although both IVIM-DTI and DTI-IVIM exhibited similar fit R2 values, the latter failed more often, especially near major blood vessels.  Thus, IVIM-DTI was concluded to be more robust and thus the better approach.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Effects of Basin Size on Streamflow in Southern Ontario

contributor:
Woo, M. K.
Geography

subject: streamflow, basin, size, river, annual, drainage

abstract:
 Daily discharge data from five Southern Ontario river systems were statistically analysed to seek relationships between streamflow characteristics and basin size. From each river system, at least two stations were used to detennine such relationships. The physiographic characteristics of each river system were also examined and qualitatively related to the streamflow statistics. Comparisons between physiographic regions were expected to support the general nature of the results obtained for each river system.

 In Southern Ontario, drainage area is correlated with mean annual peak flows. When the flows were transformed into discharge per unit area no consistent effects of basin area on the streamflow characteristics were found. However, differences in streamflow per unit area between various sub-basins can be qualitatively explained by several physical characteristics of the drainage basins.

abstract: Thesis

abstract: Bachelor of Science (BSc)


title: The de Haas-Van Alphen Effect in Calcium

contributor:
Datars, W. R.
Physics

subject: calcium, de Hass-Vas Alphen, crystals, magnetic fields, frequency

abstract:
 The de Haas-van Alphen (dHvA) effect has been studied
in single crystals of calcium using the modulation method
in magnetic fields up to 55 kOe. Four distinct orbits were
observed with dHvA frequency minima at the [110] or [100]
directions. The results do not support calculations predicting
a disconnected first-band Fermi surface for calcium. The dHvA data of crystalline calcium is consistent with the topology of the two-OPW model in which the first band is connected and pockets of electrons are about the point L of the second zone.

abstract: Thesis

abstract: Master of Science (MSc)


title: ALLOSTERIC MECHANISMS FOR THE cAMP-DEPENDENT CONTROL OF FUNCTIONAL INTER-DOMAIN LINKERS

contributor:
MELACINI, GIUSEPPE
Chemistry and Chemical Biology

subject: Allostery, protein, linker

abstract: The activation of Protein Kinase A (PKA) and of Hyperpolarization-activated and Cyclic Nucleotide-modulated channels (HCN) is controlled by cAMP through cAMP binding domains (CBDs), which serve as cAMP-dependent conformational switches to regulate downstream signaling pathways. The binding of the cAMP allosteric effector removes the auto-inhibition imposed by linkers that are adjacent to the CBDs of PKA and HCN. However, our understanding of how cAMP binding to the structured CBD controls the adjacent inhibitory linkers is currently limited. Herein, we investigate through NMR spectroscopy the interactions between the CBDs of HCN and PKA and the respective adjacent linkers. Chapters 2 and 3 of this thesis focus on the linkers N-terminal to PKA CBD-A and CBD-B, respectively, while Chapter 4 centers on the linker N-terminal to the HCN CBD. We show that in the case of PKA the linker N-terminal to CBD-A is flexible, but is coupled to the CBD-A through state active selective interactions. In the case of the CBD-B of PKA the state selective interactions with the linker N-terminal to it are to a large extent lost and replaced by state-selective inter-CBD interactions, which in turn control the conformational ensemble accessible to the inter-domain linker. Unlike PKA, in the case of HCN, the primary mechanism of cAMP-dependent linker control is through the state-selective destabilization of the structured tetrameric N-terminal linker. Overall, this thesis reports three distinct mechanisms through which linkers in HCN and PKA serve not only as simple covalent threads, but also as integral parts of the allosteric networks underlying auto-inhibition and cAMP dependent activation.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: Cyclic adenosine monophosphate or cAMP is a second messenger that is produced by cells to control the internal cellular metabolism in response to external stimuli. The goal of this thesis is to elucidate the structural and dynamical changes that translate the cAMP signal into a specific biological response necessary for the survival of the cell. We used Nuclear Magnetic Resonance (NMR) Spectroscopy to investigate how, under physiological solution conditions, the cAMP interacts with and modifies the cAMP-dependent protein kinase A (PKA) and the hyperpolarization-activated and cyclic nucleotide-gated channels (HCN). Knowledge of both structure and dynamics on both proteins is required in order to fully understand at a molecular level how cAMP works in the human heart. The elucidation of the structural and dynamical changes associated with cAMP-binding is expected to help define general rules applicable to the design of drugs for cardiovascular disorders.


title: Young Children’s Participation and Environment Measure (YC-PEM): Cross-cultural adaptation and psychometric evaluation in children with and without developmental needs in Singapore

title: Cultural adaptation of a children's participation measure

subject:
participation
assessment
young children
culture

abstract:
Measuring the participation of young children is important in informing their health and well being and designing rehabilitation services. To our knowledge, there are no participation measures that have been developed or adapted to the Singapore context. The Young Children’s Participation and Environment Measure (YC-PEM) was developed in North America and its content may not be relevant to the Singapore context. Three studies were conducted to culturally adapt and validate the YC-PEM with children with and without developmental needs in Singapore. These studies involved (1) adapting the YC-PEM culturally based on interviews with 10 service providers and 10 parents, (2) evaluating the psychometric properties of the adapted YC-PEM with 151 children with and without developmental needs in Singapore and, (3) examining the validity and utility of the YC-PEM to describe and compare the participation patterns between children with and without developmental needs in their childcare/preschool and community environments.

The outcome of this dissertation is a culturally relevant and validated YC-PEM (Singapore) for young children with and without developmental needs, aged 0 to 7 years old. The YC-PEM (Singapore) could be used by service providers to provide participation-focused intervention and researchers to implement population-based research to improve the participation of young children in Singapore. New knowledge has been developed through the cultural adaption process of the YC-PEM. Firstly, it is important to adapt instruments culturally before they are used in a new culture, even when language translation is not required.  Secondly, cognitive interviews were found to be useful in the cultural adaption process. Thirdly, participation and perceived environmental support differences were found between children with and without developmental needs in Singapore as well as children between Singapore and America. Cultural influences such as the society’s political agenda and parental beliefs were hypothesized to have potential influence on the participation of young children.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)


title: A Study of Flat Ring Emitter Electron Guns (Part B)

contributor:
Hutcheon, R. M.
Engineering Physics

subject: flat, ring, emitting, cathode, electron, currents, emission

abstract: This is Part B of the Thesis.

abstract:
 The design and performance of a flat emitting ring on-axis electron gun suitable for use in a small reflected beam accelerator was investigated. The design constraints include a low emittance (approximately 5π cm mrad), and a small beam size with a focus approximately 13 cm from the emitting surface.

 A suitable geometry was determined theoretically and was tested with a dispenser cathode. A beam with a focus at 12.7 ± 1 cm and an emittance of approximately 7π cm mrad was obtained. However, the dispenser cathode response time to heater current changes is too large for the required gun current control.

 Experiments were done to study the mechanical and thermal properties of flat emitting foil rings, since a directly heated foil has a fast response time. Two foils were tested: 1.27 x 10^-3 cm thick tungsten and 4.57 x 10^-4 cm thick tantalum. The present simple design requires impractically thin foils (≤ 0.25 microns thick) to reach emission temperatures at feasible heater currents.

abstract: Thesis

abstract: Master of Engineering (MEngr)


title: Burney's Frolics: Violence, Laughter and Shame in Camilla; A Picture of Youth

contributor:
Walmsley, Peter
English

subject:
Frances Burney
Laughter
Shame
Camilla

abstract: This thesis examines the role of “the frolic” in Frances Burney’s Camilla. Frolics take the form of light-hearted pranks centered on ritualized public humiliation; they are comically framed and particularly painful, encouraging a discussion about the ethics of laughter and the dynamics of power operating in both Camilla and Burney’s world. The purpose of this study is twofold: firstly, this project seeks to qualify current emphasis on politeness in the eighteenth century by tracing a history of violent comedy, engaging with jestbook humour, print culture, conduct literature and theorists such as Fielding, Hobbes, Smith and Locke. This study suggests that Camilla responds to popular debates about laughter and propriety, pushing the boundaries of comic acceptability with violent pranks and the use of animal and deformity humour. Secondly, this study explores the structure of the frolic itself, its function as a system of domination and control. The prankster, a socially transgressive figure able to displace the rules governing propriety through a prank, is also a social tyrant – seizing complete control over others, causing humiliation and shame. The frolic is based on plotting, secrecy, deception and public exposure, and Burney aligns the prankster with other transgressive figures in the novel, such as guardians and mentors, who exert the same type of power over the vulnerable and the weak. Burney’s pranks bring as much pain as they do laughter, becoming an important satiric device that explores both the politics of laughter and the social forces at work in her novel.

abstract: Thesis

abstract: Master of Arts (MA)


title: ASSESSMENT OF INTERFACIAL ADHESION IN POLYMER LAMINATED SHEET METALS

contributor:
Jain, Mukesh
Mechanical Engineering

subject:
polymer laminated sheet metal
peel test
interface strength
cohesive zone model
surface roughness
residual stress

abstract:
The polymer laminated sheet metal (PLSM) is a layered material which involves a sheet metal substrate, a thin polymer film and an adhesive layer between the film and the substrate.  The adhesion properties between the bonded materials are among the most important issues in PLSM forming operations.  In this thesis, the main focus has been devoted to characterizing and improving the adhesion properties of the PLSM system for forming applications.
Metallic surface roughness evolution and residual stress development in polymer adherends are two consequences of the plastic deformation of the PLSMs.  In chapter 2, the effect of these factors on interfacial adhesion strength between metallic substrate and polymer adherend (polymer film with a thin uniform pressure-sensitive adhesive layer on one side) is investigated by devising a new experimental methodology.  This methodology is based on two different protocols for preparation of peel sample, one involving pre-straining in uniaxial tension of the metallic substrate prior to lamination and the other involving post-lamination pre-straining of the PLSM.
In chapter 3, the peel test results of two different types of PLSMs at different peel speeds are analyzed with two different approaches common in cohesive zone modeling in the literature, namely linear elastic stiffness approach and critical maximum stress approach.  The modeling results revealed the significance of the peel speed in determining the interface strength between the adhesive and metallic substrate.
In chapter 4, two mechanical treatment techniques of grinding and knurling are implemented to alter the metallic substrate surface roughness before lamination.  Peel strength of these samples are investigated at different peel speeds and at different peel loading directions with respect to the grinding and knurling directions.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract:
The polymer laminated sheet metal (PLSM) is a layered material which involves a sheet metal substrate, a thin polymer film and an adhesive layer between the film and the substrate.  In this thesis, the main focus has been devoted to characterizing and improving the adhesion properties of the PLSM system for forming applications.
A new experimental methodology has been devised for analyzing the effects of deformation-induced surface roughness of metallic substrate and deformation-induced residual stress in polymer adherends on interfacial peel properties of PLSMs.
A novel interpretation of the results obtained from rate-independent cohesive zone modeling of peel test has revealed the significance of peel speed in determining the interface strength between the adhesive and the metallic substrate.
In another part of this thesis, the effects of two substrate surface alteration techniques, grinding and knurling, on peel properties of PLSMs have been studied.


title: Multi-Sensor Blue LED and Touch Probe Inspection System

contributor:
Spence, Allan D.
Mechanical Engineering

subject:
multi-sensor inspection
structured light
touch-trigger probe

abstract:
In dimensional metrology, contact and non-contact measurement methods each have their own respective strengths and weaknesses. Touch-trigger probes have low uncertainty, and perform well inside deep holes, but have a relatively slow data acquisition speed. By contrast, non-contact digitizers collect high density surface point clouds in seconds, and are much less likely to suffer from sensor collision with the part, but have a higher uncertainty than touch probes. In sheet metal forming, iterative design of the stamping die is needed due to the springback of the sheet metal part. Holes or other features of first article parts may be significantly out of tolerance, so the tactile measurement path created from the Computer Aided Design (CAD) nominal has to be adjusted to avoid cosine error. In more serious cases, probe collisions or missed touches may occur. When measuring holes in thin sheet metal, determination of the touch probe path height is also a challenge if the actual surface location differs from the nominal.
  To solve this problem and seize the complimentary advantages of contact and non-contact measurement methods, a multi-sensor blue Light Emitting Diode (LED) snapshot sensor and touch-trigger probe inspection system was developed, and affixed to a Coordinate Measuring Machine (CMM). The tactile measurement path was adjusted according to the approximate positions and sizes of the features obtained from the scanner data. The system includes an in-house designed calibration target for scanner calibration and a lightweight 2-axis rotary table for multiple-orientation scanning as well. Software in programming language C for interacting with the scanner and the CMM was developed. A sample stamped sheet metal automobile part was experimentally measured. This system is currently applied to an orthogonal CMM. Suggested future works include implementation on non-Cartesian CMMs, such as articulated arm CMMs, or Computer Numerical Control (CNC) machine tools.

abstract: Thesis

abstract: Master of Applied Science (MASc)