Theses

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  • The Effect of Relative Porosity on the Survivability of a Powder Metallurgy Part During Ejection
    The Effect of Relative Porosity on the Survivability of a Powder Metallurgy Part During Ejection
    The desire to produce functional powder metallurgy (PM) components has resulted in higher compression forces during compaction. This in turn increases the ejection stresses and therefore the possibility of failure during ejection. This failure can be caused by sprig back during ejection due to frictional forces that are generated between the powder part and the die walls. In order to predict these factors a stress analysis of the powder part during ejection was done. Due to complexity, finite element analysis was used to model the powder during compaction and ejection. Since the ejection stage is the most critical stage of the PM process, it is essential to understand the factors that determine the survivability of a part during this stage. This work uses experimental data, finite element modeling and reliability analysis to determine the probability of failure of metallic powder components during the ejection phase. The results show that there is an increased possibility of failure during ejection as compaction pressure is increased. This information can be used by designers and process planners to determine the optimal process parameters that need to be adopted for optimal outcomes during powder metallurgy.
    The Effect of Steel Fibers Type and Content on the Development of Fresh and Hardened Properties and Durability of Selfconsolidating Concrete
    The Effect of Steel Fibers Type and Content on the Development of Fresh and Hardened Properties and Durability of Selfconsolidating Concrete
    Steel fiber reinforced self-consolidated concrete (SFRSCC) has the advantages of both selfconsolidated concrete and fiber reinforced concrete. Thirteen concrete mixtures (with short and long steel fiber) were prepared including control mix. The steel fiber volume fraction varied from 0 to 2.4% by the volume of concrete. The fresh properties of SCC were evaluated using slump flow test, J-ring test, V-funnel test and L-Box test. Bond strength, compressive strength and flexural tests were performed in order to investigate mechanical properties. Water sorptivity, water absorption and porosity, rapid chloride permeability test (RCPT), corrosion and freezethaw cycles tests were performed in order to investigate the durability properties. Bond strength gain of 244% with respect to control mix was observed. Moreover, the compressive strength and MOR gained 45% and 127%, respectively. There was no significant weight loss of the concrete specimen after freeze-thaw cycles for concrete mixture with steel fibers. However, flexural toughness was reduced after freeze-thaw cycles.
    The Effectiveness of Associative and Rational Statistical Learning in Reducing Children’s Stereotype Formation
    The Effectiveness of Associative and Rational Statistical Learning in Reducing Children’s Stereotype Formation
    A stereotype is a rigid and overgeneralized belief about the characteristics of a social group. Stereotyping is a pervasive phenomenon, and has detrimental effects on children’s development such that it leads to biased information processing and stereotype threat. One of the underlying mechanisms for stereotype formation is illusory correlation, which refers to the erroneous inference about the relationship between two categories of events that in fact are uncorrelated. Given that most of the stereotype reduction training is focused on adults rather than children, this Master’s thesis aimed to examine the effectiveness of two methods that could potentially reduce stereotyping in children. More specifically, this work investigated whether facilitating associative and rational statistical learning could reduce stereotyping in children through inhibiting the formation of illusory correlation. The results showed that 5- to 10-year-old children consistently perceive an illusory correlation between the numerically smaller minority group and the infrequently occurring, negative behaviour. However, the perception of an illusory correlation among 5- to 8-year-olds was significantly reduced through the facilitation of statistical learning, but not associative learning.
    The Effectiveness of Roofing Cool Coatings On The Building Energy Demand In A Cold Climate
    The Effectiveness of Roofing Cool Coatings On The Building Energy Demand In A Cold Climate
    An average temperature increase of 2oC over the last 140 years in Toronto may not seem significant, but in reality heating demand for buildings will go down by impacting natural gas usage while cooling demand will go up by impacting electricity-usage. For preparedness against hot summer in cold climate, passive cooling needs to be adopted for building energy efficiency. In warm climate, cool roof technology proves effectiveness in reducing cooling energy demand of buildings but its use in cold climate is not much seen. Thus it is interesting to investigate the effectiveness of cool roofs in cold climate. This study investigates the properties of cool coatings available in North America, their performance on aging and energy saving benefits. The first phase of research includes selection of building, collection of information, field measurement of surface temperatures of the studied building and also lab testing of collected samples. The second phase includes energy modelling of the studied building with validation to understand their energy saving benefits. Finally the most effective cool coating for the studied building is recommended.
    The Effects of Temporality and Spatiality Due to Aged Data in LIfe Cycle Assessments
    The Effects of Temporality and Spatiality Due to Aged Data in LIfe Cycle Assessments
    Life cycle assessment is a relatively new—although decades old—method for assessing the environmental impacts of goods and services. It seeks to quantify these impacts in such a manner as to facilitate informed decisions regarding different, yet equally viable, options. However, this aim must be conditional on the notion that these impacts are measured with a number of associated qualifications or caveats, two of which is subject of this work. As subject matter, temporality and spatiality in life cycle assessment are both very broad, although this dissertation focuses specifically on temporality and spatiality due to age of data. The structure of the dissertation follows three distinct phases. The first phase contextualized the subject matter and its relation towards standardization of life cycle assessment methods. In doing so, it identifies and contextualizes the subject matter. The second phase identified Greenhouse gases, Regulatory Emissions, and Energy use in Transportation 2 as an ideal model on which to assess temporality and spatiality due to age of data since it models the life cycle assessment of an assortment of different vehicles. This phase also involved data collection, and uses a platform of assessment tools including Monte Carlo simulations, analysis of variance, F tests, regression analysis, and tests for non-normality (kurtosis and skewness). Building on the second phase, the third phase moved beyond the original phases by more than doubling the amount of materials of manufacture to be studied and adding further tools for assessment, the mainstay of which are regression analyses. Overall, this study found that the use of Monte Carlo simulations and analysis of variance are useful for identifying long term variation in energy intensity of materials. F-tests were useful in identifying which materials showed effects owing to spatiality. Although not in all instances, tests for non-normality identified which circumstances merit log transformation to bring about more accurate results. Linear regression techniques were used as a posterior test to confirm the origins of the variation seen in the Monte Carlo simulations and the analysis of variation. Moving ahead, this study pointed to the need for more concerted efforts in data promulgation.
    The Efficacy Of Singing In Foreign-Language Learning
    The Efficacy Of Singing In Foreign-Language Learning
    This study extends the popular notion that memory for text can be supported by song to foreign-language learning. Singing can be intrinsically motivating, attention focusing, and simply enjoyable for learners of all ages. The melodic and rhythmic context of song enhances recall of native text; however, there is limited evidence that these benefits extend to foreign text. In this study, Spanish-speaking Ecuadorian children learned a novel English passage for two weeks. Children in a sung condition learned the passage as a song and children in the spoken condition learned the passage as an oral poem. Children were tested on their ability to recall the passage verbatim, pronounce English vowel sounds, and translate target terms from English to Spanish. As predicted, children in the sung condition outperformed children in the spoken condition in all three domains. The song advantage persevered after a six-month delay. Findings have important implications for foreign-language instruction.
    The Efficacy of Facebook as a Tool in Criminal Investigations
    The Efficacy of Facebook as a Tool in Criminal Investigations
    June 15, 2011 marked the date of the Vancouver riots that followed the Canucks loss of the Stanley Cup final. Social media as a form of communication between the public and police was a distinguishing feature during the 2011 riots, and is compared to the context of a similar Vancouver riot occurring in 1994. Through the review of literature on the criminal justice system, crowdsourcing, social media as a tool in policing, surveillance, language on Facebook and Facebook as a communication tool I explore the practice of communication as it unfolds on the Facebook group, “Vancouver Riot Pics: Post Your Photos” and examine the efficacy of this communication tool. The Facebook comments underneath the uploaded images are evaluated through a content analysis. Five Facebook images and there associated comment threads are collected in chronological order for the sample based on the outlined criteria of: 25-40 comments, a non-manipulated image, and being published in either the Globe and Mail or the National Post online news source. Erving Goffman’s theoretical orientation of frame analysis is applied to understanding the development of the Facebook comments; more specifically his concept of the social primary framework is directly related to the intended purpose outlined by the Facebook group. The purpose of “Vancouver Riot Pics: Post Your Photos” is to identify rioters through the public’s contribution of images and Facebook comments. Research findings suggest that the intended purpose of the Facebook group is achieved, as there is a significant emergence of the frames identification and crowdsourcing; therefore, Facebook is deemed a helpful tool in police investigation.
    The Enrichment And Characterization Of Compost And Wastewater-Derived Microbial Cellulolytic Consortia For Biofuel Production
    The Enrichment And Characterization Of Compost And Wastewater-Derived Microbial Cellulolytic Consortia For Biofuel Production
    Over the last decade, a rise in energy demand and diminishing fuel resources have created a challenge for finding an alternative solution that could supplement our current energy sources. This study demonstrated that ethanol and other useful end-products can be produced from the fermentative activity of microbial consortia derived from cellulose-rich waste environments. Compost and wastewater were used as inoculum sources to enrich cellulolytic cultures at incubation temperatures 50 ºC and 60ºC. A chemically defined medium was used without complex nutrients such as yeast extract. Four cellulolytic cultures were obtained and their end-products were monitored over an active cellulose degrading period. The compost culture incubated at 50ºC produced the highest concentration of butyrate while the wastewater-derived culture incubated at 60ºC produced the highest ethanol concentration. Optimization of DNA extraction and purification from complex environmental samples such as the compost and wastewater cultures used in this study was also discussed.
    The Evolution and Spatial Dimensions of Invention in Canada, 1991 - 2011
    The Evolution and Spatial Dimensions of Invention in Canada, 1991 - 2011
    The rapid development of information technology and medical research in the 21st century is a result of the increasing number of inventions. Inventive activity is thought to be an important catalyst for economic change and increased productivity. In order to measure a location’s inventive potential, different aspects such as geographic location, corporate assistance, and socio-economic factors can be studied. This study examines the spatial distribution and typology of Canadian inventions for the years 1991, 2001, 2006, and 2011, using patent data issued by the United States Patent and Trademark Office. The research results suggest that inventive activity is declining in major metropolitan areas such as Toronto, Vancouver, and Montreal. On the other hand, medium-sized metropolitan areas like Ottawa, Calgary, Kitchener-Waterloo, and Saskatoon are experiencing increasing inventiveness. These areas have specialized economies based on high technology and petroleum. The regression analysis shows that regional innovation can be explained by census variables in groups of dwelling type, education level, and industry sector. The analysis also shows Canada has shifted from a manufacturing economy to a high technology and services-based economy.
    The Exiled Spaces Of The City: Transforming Laneways Into Community Spaces
    The Exiled Spaces Of The City: Transforming Laneways Into Community Spaces
    This goal of this project is to re-imagine a derelict, underutilized, and exiled laneway in the Roncesvalles Village neighbourhood (alternatively known as ‘Roncy’), into a place that can be celebrated and used by the community. I imagine it to be a project that expands the street level excitement into the laneways. This project is heavily grounded in the practical. The idea for it flourished while standing on a rooftop of a building during a festival in the ‘Roncy’ neighbourhood. After spending the afternoon on the ground we retreated from the busy street to a private rooftop. From here, I was able to watch as people squeezed by each other enjoying street vendors and local artisans and music. But I could also see the intricate network of laneways that stood vacant and still amidst the heavy traffic on the street below. Since then I’ve spent countless hours wandering through the laneways in Roncy hoping to see activity, kids playing, informal economies, or seniors sitting and reading books. But alas, the only people I’ve come across are those looking through garbage and recycle bins in search of bottles to return for a few cents.
    The Experiences And Perceived Differences In Working Conditions Among Early Childhood Educators Who Have Worked In Both For-Profit And Non-Profit Childcare Centres In The Greater Toronto Area
    The Experiences And Perceived Differences In Working Conditions Among Early Childhood Educators Who Have Worked In Both For-Profit And Non-Profit Childcare Centres In The Greater Toronto Area
    This study examined early childhood educators’ perceptions of the differences in working conditions between for-profit and non-profit childcare centres and childcare sectors, in the Greater Toronto Area. Four early childhood educators who have worked in both for-profit and non-profit childcare centres were interviewed. This project was guided by Moss’ theory of democratic political practice with the goals of illuminating why early childhood education and care (ECEC) should be a public system and how researchers can ensure that ECEs’ experiences and voices are highlighted especially in early childhood practices and policies affecting them. Two themes emerged from the interviews. The first theme reveals variation between the material conditions in the participants’ working environments across the two sectors; the second theme exposes non-material factors of working in each sector as an ECE. Interviewed ECEs reported that non-profit childcare centres provide higher quality working conditions than forprofit childcare centres.