There has been a constant need for low power techniques to achieve high performance at the lowest possible power dissipation. Lots of works have been done to achieve this target. These works have focused on the different aspects of power reduction. One of these aspects of power saving is Dynamic power reduction. This thesis work is focused on this aspect of power saving by reducing the unnecessary transitioning in the circuit. To achieve this, new method called data gating, is proposed here which stops unnecessary toggling in the circuit using different forms of gating mechanisms. This thesis is organized as follows; first chapter is about the low power design of CMOS circuits. That chapter covers the sources of power dissipation in ICs as well as the techniques that have been used to minimize the power consumption. Second chapter talks more about dynamic power consumption. Techniques used for reducing dynamic power consumption through reduction in switching activities are mentioned in that chapter. Also the new technique, Data Gating, to reduce dynamic power is proposed in second chapter. Third chapter talks about simulation setup, tools used for simulation. Results obtained from different simulations are presented in that chapter. Fourth Chapter is about the analysis of simulation results. It also outlines some possible limitations of the proposed method as well as certain points that need to be considered before applying new technique. Fifth and final chapter summarizes the conclusion and possible future work that can be done to enhance the proposed technique, Data Gating. / text

This thesis conducted a secondary quantitative analysis to test predictors of punitive attitudes about the best overall and youth crime reduction methods in Saskatchewan, and to examine an integrated perspective developed from Bourdieu’s concept of habitus. My research questions were twofold: 1) What are the valid predictors of punitive attitudes toward overall and youth crime respectively? 2) Is there a difference in punitive attitudes between overall crime and youth crime? For my research methodology, I relied on a secondary quantitative analysis of data from Taking the Pulse of Saskatchewan 2012, a survey conducted by the Social Sciences Research Laboratories (SSRL) of the University of Saskatchewan. The data used in this thesis was taken from Section (F), Crime and Public Safety in Saskatchewan, and Section (H), demographics. I examined three types of predictors: demographics, fear of crime, and perception of crime trends. The demographic variables were gender, age, education, marital status, race, and total annual household income. The relationship between these predictors and the public’s punitive attitudes were first examined with a bivariate analysis. Then logistic regression analysis was used to determine the effect of a selected predictor of punitive attitudes when other predictors were controlled. This thesis reported three major findings. First, the mutual predictors of punitive attitudes towards overall and youth crime are age, education, marital status, and perceived crime trends, while gender is significant only for overall crime, and race is significant only for youth crime when other variables are controlled. Secondly, with regard to the magnitude of influence, the variables perceived crime trends and education are the strongest predictors among all the predictors considered in this study, but any single predictor only has small impact on punitive attitudes. Finally, respondents are generally less punitive towards youth crime than overall crime. This thesis revealed that an integrated Bourdieuian perspective used in this study helped link the predictors in a more explanatory manner, and contributed to a more critical and contextual understanding of punitive attitudes. The empirical results reported in this thesis produced knowledge about punitive attitudes in Saskatchewan, and contributed to the literature on predictors of such attitudes.

Not available / text

Proton exchange membrane fuel cells (PEMFC) are attractive power sources as they offer high conversion efficiencies with low or no pollution. However, several challenges, especially the sluggish oxygen reduction reaction (ORR) and the high cost of Pt catalysts, impede their commercialization. With an aim to search for more active, less expensive, and more stable ORR catalysts than Pt, this dissertation focuses on the development of non-platinum or low-platinum Pd-based nanostructured electrocatalysts and a fundamental understanding of their structure-property-performance relationships. Carbon-supported Pd–Ni nanoalloy electrocatalysts with different Pd/Ni atomic ratios have been synthesized by a modified polyol reduction method, followed by heat treatment in a reducing atmosphere at 500–900 oC. The Pd–Ni sample with a Pd:Ni atomic ratio of 4:1 after heat treatment at 500 °C exhibits the highest electrochemical surface area and catalytic activity. The enhanced activity of Pd80Ni20 compared to that of Pd is attributed to Pd enrichment on the surface and the consequent lattice-strain effects. To improve the catalytic activity and long-term durability of the Pd–Ni catalysts, Pd–Pt–Ni nanoalloys have been synthesized by the same method and evaluated in PEMFC. The Pt-based mass activity of the Pd–Pt–Ni catalysts exceeds that of commercial Pt by a factor of 2, and its long-term durability is comparable to commercial Pt within the testing duration of 180 h. Both the favorable and detrimental effects of Pd and Ni dissolution on the performance of the membrane-electrode assembly (MEA) have been investigated by compositional analysis by transmission electron microscopy (TEM) of the MEAs before and after the fuel cell test. The MEAs of the Pd–Pt–Ni catalyst have then been characterized in-situ by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) to better understand the performance changes during cell operation. The surface state change from Pd-enrichment to Pt-enrichment and the consequent decrease in the charge transfer resistance during cell operation is believed to contribute to the activity enhancement. To further improve the MEA performance and durability, the as-synthesized Pd–Pt–Ni catalysts have been pre-leached in acid and Pd–Pt alloy catalysts have been synthesized to alleviate contamination from dissolved metal ions. Compared to the pristine Pd–Pt–Ni catalyst, the preleached catalyst shows improved performance and the Pd–Pt catalyst exhibits similar performance in the entire current density range. Finally, the catalytic activities for ORR obtained from the rotating disk electrode (RDE) and PEMFC single-cell measurements of all the catalysts are compared. The improvement in the activities of the Pd-Pt-based catalysts compared to that of Pt measured by the RDE experiments is much lower than that obtained in single cell test. In other words, RDE tests underestimate the value of the Pd-Pt-based electrocatalysts for real fuel cell applications. Also, based on the RDE data, the Pd–Pt–Cu catalyst exhibits the highest catalytic activity among all the Pd–Pt–M (M = Fe, Ni, Cu) catalysts studied. / text

We show the existence of a basis for a vector space over a number field with two key properties. First, the n-th basis vector has a small twisted height which is bounded above by a quantity involving the n-th successive minima associated with the twisted height. Second, at each place v of the number field, the images of the basis vectors under the automorphism associated with the twisted height satisfy near-orthogonality conditions analagous to those introduced by Korkin and Zolotarev in the classical Geometry of Numbers. Using this basis, we bound the Mahler product associated with the twisted height. This is the product of a successive minimum of a twisted height with the corresponding successive minimum of its dual twisted height. Previous work by Roy and Thunder in [12] showed that the Mahler product was bounded above by a quantity which grows exponentially as the dimension of the vector space increases. In this work, we demonstrate an upper bound that exhibits polynomial growth as the dimension of the vector space increases. / text

published_or_final_version / Mechanical Engineering / Master / Master of Philosophy

published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

No description available.

No description available.

This research has been directed at the study of facilitated oxidation of aliphatic sulfides by neighboring group participation. Mesocyclic polythioether and 2-substituted 6-methylthiobicyclo[2.2.1]heptane derivatives have been examined as model compounds for biological redox reactions. The preparations, structural analogues, and oxidation studies of such compounds have been investigated. A new technique has been developed for the preparation of mesocyclic polythioethers. Conformational analysis, both gas phase and solid state, and quantum mechanical analysis of one- and two-electron oxidation of mesocyclic polythioethers have been undertaken. Crystal and molecular structures of some transition metal complexes of 1,4,7-trithiacyclononane, as well as a number of 2-substituted 6-methylthiobicyclo[2.2.1]heptane derivatives have been determined using single crystal X-ray techniques. Stereoselective oxidation of 2-endo-(hydroxymethyl)-6- endo(methylthio)bicyclo[2.2.1]heptane has been achieved leading to both corresponding diastereomeric sulfoxides.