title: Spiro Oxadiazolines - Source of Cyclic Dioxa Carbenes

contributor:
Warkentin, John
Chemistry

subject: spiro, cyclic, dioxa, carbenes, source, formation, oxidation

abstract:
 It is known that alkoxyoxadiazolines undergo thermal decomposition to form carbenes via an ylide intermediate. This project involved the preparation and subsequent thermolysis of spirooxadiazolines of type 4.

 Spiro oxadiazoline (4) was prepared by oxidation of (3) with lead tetraacetate in dichloromethane. The first order rate constant for the thermolysis of 4b in benzene at 111°C is determined. The primary thermolysis products were found to be acetone, nitrogen and the cyclic dioxacarbene (5). Formation of (5) was confirmed by various trapping experiments. (See Diagram in Thesis)

abstract: Thesis

abstract: Master of Science (MSc)


title: Strain Measurements from Deformed Quartz Grains in Metagreywackes of the Goldenville Formation, Meguma Group, Nova Scotia

contributor:
Clifford, P. M.
Geology

subject: strain, deformed, quartz, grains, formation, metagreywackes

abstract: Metagreywackes of the Goldenville Formation, Nova Scotia, possess a well developed penetrative cleavage. Measurement of strain, based on quartz grain shape, indicates that much of the strain has been achieved by pressure solution of detrital quartz grains. Strain ratios in the system range from X/Z = 3.8 in cleavage zones, through 2.0 in intermediate areas, to 1.6 in lithons. The volume lost from cleavage zones ranges from 60 to 70 percent, while loss of volume to the system as a whole is 40 percent or greater. Strain due to plastic deformation is minimal, relative to the strain due to volume loss. The strain within the system is not homogeneous on a centimeter scale, but rather range from low values in mid-lithon zones to much higher values in cleavage zones. Lithon and intermediate areas are representative of the deformation history of the cleavage.

abstract: Thesis

abstract: Bachelor of Science (BSc)


title: Some Inferential Results for One-Shot Device Testing Data Analysis

contributor:
Balakrishnan, Narayanaswamy
Mathematics and Statistics

subject:
one-shot device testing
competing risk
multinomial data
censoring
accelerated life testing
exponential distribution
Weibull distribution
semi-parametric method
proportional hazard model
EM algorithm
Bayesian approach
asymptotic method
parametric bootstrap
inequality constrained least square
point estimation
confidence interval
transformation approach

abstract:
In this thesis,  we develop some inferential results for one-shot device testing data analysis. These extend and generalize existing methods in the literature.

 First, a competing-risk model is introduced for one-shot testing data under accelerated life-tests. One-shot devices are products which will be destroyed immediately after use. Therefore, we can observe only a binary status as data, success or failure, of such products instead of its lifetime. Many one-shot devices contain multiple components and failure of any one of them will lead to the failure of the device. Failed devices are inspected to identify the specific cause of failure. Since the exact lifetime is not observed, EM algorithm becomes a natural tool to obtain the maximum likelihood estimates of the model parameters. Here, we develop the EM algorithm for competing exponential and Weibull cases.

 Second, a semi-parametric approach is developed for simple one-shot device testing data. Semi-parametric estimation is a model that consists of parametric and non-parametric components. For this purpose, we only assume the hazards at different stress levels are proportional to each other, but no distributional assumption is made on the lifetimes. This provides a greater flexibility in model fitting and enables us to examine the relationship between the reliability of devices and the stress factors.

  Third, Bayesian inference is developed for one-shot device testing data under exponential distribution and Weibull distribution with non-constant shape parameters for competing risks. Bayesian framework provides statistical inference from another perspective. It assumes the model parameters to be random and then improves the inference by incorporating expert's experience as  prior information. This method is shown to be very useful if we have limited failure observation wherein the maximum likelihood estimator may not exist.

The thesis proceeds as follows. In Chapter 2, we assume the one-shot devices to have two components with lifetimes having exponential distributions with multiple stress factors. We then develop an EM algorithm for developing likelihood inference for the model parameters as well as some useful reliability characteristics. In Chapter 3, we generalize to the situation when lifetimes follow a Weibull distribution with non-constant shape parameters. In Chapter 4, we propose a semi-parametric model for simple one-shot device test data based on proportional hazards model and develop associated inferential results.  In Chapter 5, we consider the competing risk model with exponential lifetimes and develop inference by adopting the Bayesian approach. In Chapter 6, we generalize these results on Bayesian inference to the situation when the lifetimes have a Weibull distribution.   Finally, we provide some concluding remarks and indicate some future research directions in Chapter 7.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Photosolvolysis of 1-Benzoyl-5-Bromo-7-Nitroindoline (A Mechanistic Study)

contributor:
Childs, R. F.
Chemistry

subject: photosolvolysis, mechanistic, charge-mosaic, membranes, solvent, energies, polarity, spectrometer, reaction

abstract:
 This thesis describes a study of the photosolvolysis of N-benzoyl-5-bromo-7-nitroindoline. The investigation was instigated because N-acyl-5-bromo-7-nitroindolines have been considered as potential photoprotecting groups for the photolithographic formation of charge-mosaic membranes. However, no kinetic data, and only scant mechanistic information, has been reported for the photofragmentation process.

 Both absorption and emission spectra of N-benzoyl-5-bromo-7-nitroindoline were obtained. Based on the electronic spectra, it would seem that the two lowest energy singlet excited states are nearly isoenergetic and their relative energies are a function of the solvent medium.

 The distribution of photoproducts obtained from irradiation of N-benzoyl-5-bromo-7-nitroindoline in various solvent systems was investigated. It was shown that the photosolvolysis reaction is a function of the solvent properties. Thus 5-bromo-7-nitroindoline and benzoic acid were the only photoproducts formed in acetonitrile. In acetonitrile-water, 5-bromo-7-nitrosoindole as well as 5-bromo-7-nitroindoline and benzoic acid were identified. A correlation between solvent polarity, ET(30), and 5-bromo-7-nitrosoindole formation was observed.

 The mechanism of the fragmentation mode was examined. The presence of a free radical intermediate is suggested from the photoproduct distribution in tetrahydrofuran (THF). Observation of an electron spin resonance (e.s.r.) spectrum during irradiation of N-benzoyl-5-bromo-7-nitroindoline in an e.s.r. spectrometer cavity, 18_0 incorporation into benzoic acid, and a linear free energy relationship with sigma dot (σ•) corroborated the intermediacy of a free radical in the fragmentation process.

 Quantum yields of N-benzoyl-5-bromo-7-nitroindoline disappearance in different solvents and quenchers were measured in order to establish the reactive excited state and the effect of the medium on the efficiency of the transformation process. A solvent dependency on both the excited state lifetime and photosolvolysis reaction efficiency was noted. The results were indicative of a change in mechanism with a variation in solvent polarity and/or hydrogen bonding ability.

 A mechanism compatible with experimental results and applicable to previously reported N-acyl-2-nitroaniline photofragmentations is proposed.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: ESR Dating of Pleistocene Deposits

contributor:
Schwarcz, Henry P.
Geology

subject: ESr, dating, pleistocene, deposits, sediments, tooth, fragments, enamel

abstract:
 Near Medicine Hat, Alberta, Pleistocene deposits are exposed on numerous bluffs along the South Saskatchewan River. The Quaternary beds are very fossiliferous, yielding a large number of mammal bones and teeth. The enamel (calcium hydroxyapatite) portion of teeth within the sediments, is used to date the deposits with the electron spin resonance
(ESR) dating method. The ESR age is strongly dependent on the dose rate which in turn depends on the uranium accumulation in the tooth fragments. Two U uptake models are used based on an early and a continuous, linear accumulation of uranium.

 At young, well dated sites the ESR ages are in relatively good agreement with independent estimates. For slightly older samples (approx. 100 ka), the linear U uptake model comes closer to the estimated age at one site, but at another site, the early U uptake model agrees more favourably with the estimated age. Based on the ESR ages, several older sites can be assigned to interglacial stages 7, 9 and 13, however, these ages are much younger than those determined by faunal and stratigraphic correlation (>0.5 Ma). Samples with extremely high U contents in dentine and enamel gave unreliable ESR results. These samples may have experienced a late stage of U accumulation.

abstract: Thesis

abstract: Master of Science (MSc)


title: Further Sulphur Isotope Studies of the Taolin Lead-Zinc Ore Deposit

contributor:
Rees, C. E.
Geology

subject: sulphur, isotope, Taolin, lead-zinc, ore, deposit, mineral, temperatures, precipitation

abstract: Sulphur isotope data from coexisting sulphides and sulphates from the 120m level of the Shangtancen ore body of the Taolin Pb-Zn ore deposit have been used to estimate the temperatures of sulphur mineral precipitation. The data indicate that sulphide was the dominant species in solution at both high and low temperatures. The data also show that the 𝛿34S value of total sulphur in solution was close to zero at high temperatures, but had low negative values (about -6.7‰) at low temperatures. This is interpreted in terms of the effects of mineral precipitation on the isotopic 34 composition of the solution. The decrease of the 𝛿34S value of the total sulphur with decreasing temperature was brought about because the removal from the system, by precipitation, of isotopically heavy sulphate exceeded the removal from the system, by precipitation, of isotopically light sulphide.

abstract: Thesis

abstract: Bachelor of Science (BSc)


title: The Postglacial Population Spread of Picea Mariana, Picea Glauca, and Pinus Banksiana Across the Western Interior of Canada

contributor:
MacDonald, G. M.
Geography

subject: postglacial, population, spread, Picea mariana, picea glauca, Interior, western, Canada, fossil, sediments, pollen, species

abstract:
 In this thesis, the postglacial spread of three ecologically distinct species, Picea mariana (black spruce), Picea glauca (white spruce), and Pinus banksiana (jack pine), across the western interior of Canada are presented. The fossil pollen records from the sediments of thirteen lakes are used in reconstructing the population expansions of the three tree taxa. The objectives of this study are to examine temporal and spatial patterns in the growth of the populations and to determine if intraspecific and interspecific variations exist across a range of latitudes and elevations.

 Pollen accumulation rates (PAR) are calculated from pollen grain counts and sedimentation rates throughout the early-to mid-Holocene, and are used to represent the population level at the time of pollen deposition. Exponential equations are used to calculate population growth rates. Three dimensional diagrams (time, space, abundance) are constructed to illustrate the spread of the populations.

 The rates of population growth varied from south to north for all three species. Jack pine, on average had slower population growth rates, and its expansion across the region began over 3,000 years later than, and lasted approximately 1,000 years longer than the two spruce species. All three tree taxa experienced reduced rates of population growth at high elevation sites in the north. These variations are examined in light of the changing and static physical and botanical environmental conditions occurring during expansion.

abstract: Thesis

abstract: Master of Science (MSc)


title: Low Valent Technetium Nitrosyl Complexes

contributor:
Bell, Russell Arthur
Thornback, John Richard
Lyne Lock, Colin James
Chemistry

subject: low, valent, technetium, nitrosyl, complexes, ligands, species, equilibrium, reactions, structure

abstract: Page 39 was included twice in the thesis.

abstract:
 This thesis describes reactions involving low valent technetium nitrosyl complexes. O-Substituted hydroxylamines were reacted with [TcOCl4]- in methanol producing [Tc(NO)Cl4]-. NMR studies have shown that two species are present besides the starting material during this reaction. One of these species was confirmed by NMR to be the corresponding alcohol of the O-substituted hydroxylamine. The other species is believed to be a hydroxylamine intermediate that is in equilibrium with the final product, [Tc(NO)Cl4]-. A plausible mechanism for this reaction was proposed that included an oxo group attack of the α-carbon of the O-substituted hydroxylamine which would lead to the formation of the corresponding alcohol. In an attempt to confirm the mechanism, O-18 labeled [TcOCl4]- was synthesized, however, there is no conclusive evidence that the label is transferred to the corresponding alcohol at the present time. Substitution reactions of [Tc(NO)Cl4]- with phenanthroline and bipyridyl ligands were also investigated. Reactions with these ligands produced [Tc^(II)(NO)Cl3phen] (4a) and [Tc^(II)(NO)Cl3bipy] (5), respectively. The crystal structures of these complexes showed that the meridonial isomer is produced with one nitrogen atom of the bidentate ligand trans to the nitrosyl moiety. EPR spectra of these compounds confirm the Tc(II) oxidation state of the metal. All of the chloride ligands of 4a and 5 can be displaced
using AgBF4 in acetonitrile solvent, which, in the case of bipyridyl, produces
[Tc^(I)(NO)(bipy)2(MeCN)]2+ (6). Other technetium nitrosyl containing complexes are
formed in these reactions and are currently awaiting x-ray structure determination.

abstract: Thesis

abstract: Master of Science (MSc)


title: Polyvinyl Alcohol as a Steric Stabilizer

contributor:
Woods, D. R.
Chemical Engineering

subject: polyvinyl, alcohol, steric, stabilizer, soluble, lamella, polymer

abstract:
 An experimental study of the steric stabilizing ability of a water soluble polyvinyl alcohol (PVA) polymer is presented.

 The free film thickness of a lamella formed between a drop of n-butylchloride and bulk n-butylchloride stabilized by PVA was measured by the Hodgson and Woods technique in order to evaluate the stabilizing ability of the polymer. A maximum in the stability was observed as the concentration of the polymer was increased. This maximum trend can be explained by the HVO theory.

abstract: Thesis

abstract: Master of Engineering (MEngr)


title: The Statistical Analysis of Light Scattering Data for Polymer Characterization

contributor:
MacGregor, J. F.
Chemical Engineering

subject: statistical, analysis, light, scattering, data, polymer, characterization, linear, particle

abstract:
 The models derived from classical light scattering theory for predicting Rayleigh light scattering contain useful parameters such as polymer weight average molecular weight, z-average radius of gyration and virial coefficients. The methods used to estimate these model parameters have not been based on sound statistical principles. It is with improved statistical estimation methods for these parameters that this thesis is concerned with. The methods of linear least squares, non-linear least squares and error propagation were applied to the analysis of wide angle and low angle laser light scattering data and the results compared.

 From the theory of dynamic light scattering, methods have been developed to reconstruct particle size distributions of unimodal, bimodal and polydisperse polymer solutions from the data accumulated in a single experiment. Some of these methods of reconstruction are based upon the estimation of the coefficients in a sum of exponentials. Estimating sums of exponentials is a highly ill-conditioned problem and the problems encountered thereof are examined in this thesis. Linear least squares, non-linear least squares and exponential sampling techniques were applied to experimental data from a number of simulated polymer distributions and the final results compared.

abstract: Thesis

abstract: Master of Engineering (MEngr)


title: Photochemistry and Thermolysis of the 1,1-Diphenylindene System

contributor:
McCullough, J. J.
Chemistry

subject: photochemistry, thermolysis, system, phenyl, donor-accepting, charge, pairs

abstract:
 1,1-Diarylindenes rearrange when heated or irradiated to give 1,2- and 2,3-diarylindenes. Three 1,1-diarylindenes were synthesized and used in an attempt to probe the transition states for phenyl migration in both the ground and excited state. The three indenes synthesized were: 1-(p-bromophenyl)-1-phenylindene, 1-(p-cyanophenyl)-1-phenylindene and 1-(p-methoxyphenyl)-1-phenylindene.

 On direct irradiation, the migratory aptitudes were -C6H4CN-p, 98%; -C6H4OCH3-p, 95%; and -C6H4Br-p, 86%. On heating (258°C) the following aptitudes were found: -C6H4CN-p, 82%; -C6H4OCH3-p, 48%; and -C6H4Br-p, 53%. The products were synthesized independently, and the product ratios obtained upon reaction were measured from the n.m.r. of mixtures, and by v.p.c. A charge transfer mechanism was put forward to explain the preference for migration of the substituted group in the excited state. Such charge transfer contributions are known to increase the rates of quenching in donor-acceptor pairs. A radical-type transition state was postulated as being present in the ground state migration. The rate constant for excited state rearrangement was calculated to be 4.9 x 10^9 sec^-1 .

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: The Preparation, Multinuclear Magnetic Resonance and Solid-State Investigation of Some Classically Bonded Anions of the Heavy Main-Group Elements Derived from Zintl Phases

contributor:
Schrobilgen, G. J.
Chemistry

subject: preparation, multinuclear, magnetic, resonance, solid-state, bonded, anions, main-group, elements, zintl, phases

abstract:
 The synthesis and X-ray crystallographic determination of solid derivatives of homo- and heteropolyatomic anions derived from Zintl phases has generally yielded the least soluble of the ions present in solution. Many other species present in these solutions have remained unidentified until recently when considerable effort directed towards the investigation of the solution chemistries of Zintl anions has been put forth.

 The present work is mainly concerned with the characterization of new Zintl anions in solution using multinuclear magnetic resonance spectroscopy as the primary investigative tool. These studies include (1) the tetrahedral SnCh4^4- (Ch = selenium and/or tellurium), (2) the dimer of SnSe3^2-, Sn2Se6^4-, (3) several interesting but, as-of-yet, unidentified species present in solutions derived from ternary Na/Sn/Te alloys and present in the reaction of Sn(II) Cl2 with Te2^2-, and (4) a set of possible multi-thallium-tellurium species. Relevant chemical shifts and nuclear spin-spin coupling constants are reported and trends discussed.

119Sn Mössbauer investigations of all tin-containing species is also presented as is a brief discussion of the
X-ray crystallographically determined polytelluride, Te4^2-.

abstract: Thesis

abstract: Master of Science (MSc)


title: Experimental Determination of Beta Attenuation in Tooth Enamel Layers and its Implication in ESR Dating

contributor:
Rink, W. J.
Schwarcz, H. P.
Geology

subject: experimental, determination, beta, attenuation, tooth, enamel, ESR, dating

abstract:
 The principal subject of this thesis is to experimentally determine the beta attenuation patterns in tooth enamel layers, and to examine the predictions of two theoretical models which are involved in the beta dose calculations of ESR dating. One of the models is based on empirical equations (Yokoyama, 1982) and employed by R.Grün (1986) in the DATA software of ESR dating, the other is based on the "one group" transport theory which was incorporated in the ROSY dating programme (B.J. Brennan, et al., 1997).

 The theoretical bases of Grün's approximation (i.e. the empirical approach) and the "one group" transport theory are discussed. Their predictions of beta attenuation under 2-π geometry are compared with the results of Monte Carlo simulations, and were then compared with the results of our experimental work, which show clear inclination to the predictions of "one group" theory and Monte Carlo. The previous experiment of Aitken et al.(1985) is also described and its flawed geometric arrangement is discussed.

 In this study, two sets of experiments are performed. The first set used pitchblende as the irradiator and employed the configuration of irradiator-absorber-detector, which is aimed to reassess the experiment of Aitken et al. (1985). The second set of our experiments used a pure beta source of 90Sr(90Y) and employed the innovative configuration of tooth enamel pellets in a hole of tooth enamel holder, which substantially solved the problem encountered in the first set (e.g. gamma background subtraction and non-2π geometry, etc.).

 Based on our experimental results as well as the discussion of Aitken et al.'s experiment, a conclusion is drawn that the "one group" theory is more reliable in predicting beta doses in ESR dating samples, and consequently, it challenges the ESR ages calculated by DATA software which employs the empirical approach. The comparison of ESR ages calculated by the two dating programmes is shown, and some revisions of published ESR ages based on DATA programme demonstrate the great significance of our experimental results.

abstract: Thesis

abstract: Master of Science (MSc)


title: Fabrication of LiYO2 Galvanic Cells to Determine the Thermodynamic Properties of Lithium Alloys

contributor:
Petric, Anthony
Materials Science and Engineering

subject: fabrication, galvanic, cells, lithium, alloys, thermodynamic, properties, metal

abstract:
 LiYO2 is a lithium ion conductor stable to pure lithium metal. The goal of the present work was to design and construct an electrochemical cell and demonstrate the use of LiYO2 as an electrolyte since this has never been previously done. The electrolyte was fabricated by slip casting in powder molds. A Y2O3-MgO composition was identified and used to fabricate a lid for the cell. Impervious cells were obtained by liquid phase joining and sintering techniques. Heating rate was found to be a key parameter in the success of this procedure. The cell was evaluated in terms of stability as a sensor and chemical pump by measuring EMF for two different Li-Zn alloys between 250 and 600°C. The configuration was as follows:
(RE) (-) Ta Li,Sn | LiYO2 | Li,Zn Ta (+) (WE)

 The cell showed no significant attack after 40 days working with pure lithium. Stability and reproducibility of EMF values was obtained for the concentrations of Li studied. Solidus and liquidus temperatures were determined for the 5 and 10 mol% Li compositions in good agreement with published phase diagrams. Variations of EMF with respect to temperature or concentration followed the expected thermodynamic relationships. Results indicate that the LiYO2 electrolyte cell could be useful in assessment of the thermodynamics of lithium alloys.

abstract: Thesis

abstract: Master of Engineering (MEngr)


title: UNCONVENTIONAL HIGH-THROUGHPUT SCREENING TECHNIQUES FOR THE DISCOVERY OF CELL WALL ANTIBIOTICS

contributor:
Brown, Eric
Biochemistry and Biomedical Sciences

abstract: The emergence of antibiotic resistance in recent years has radically reduced the clinical efficacy of many antibacterial treatments and now poses a significant threat to human health. One of the earliest studied and well validated targets for antimicrobial discovery is the bacterial cell wall. The essential nature of this pathway, its conservation among bacterial pathogens, and absence in human biology have made cell wall synthesis an attractive pathway for new antibiotic drug discovery. Indeed, nearly all cell wall active agents have been discovered using screens for growth inhibition, followed by cumbersome secondary screens to identify the cell wall target. What is lacking are selective primary screening assays for the sensitive detection of cell wall active compounds while avoiding off-target and nuisance compounds. The overarching objective of this work is to explore new and unconventional screening techniques for the discovery of new cell wall antibiotics. These approaches take an integrative approach merging the positive aspects of whole-cell phenotypic and target based screening while obviating many of their individual pitfalls. Two main approaches are taken herein. First we explore the validity of using the recently developed PywaC reporter based system in B. subtilis 168 to enrich for cell wall inhibitors. A pilot screen of 26,000 small molecules led to the discovery of 9 cell wall actives of which one had its direct target identified. Secondly we harness the powerful and complex dispensability pattern found within wall teichoic acid (WTA) in Gram-positives. Developed is a powerful antagonism screen to search for early step and substrate producing WTA inhibitors. This approach led to prolific enrichment for inhibitors of undecaprenyl-pyrophosphate synthase (UppS) through the interrogation of a small molecule library of 140,000 compounds. Overall, this thesis outlines effective and innovative approaches toward the identification of novel cell wall active compounds.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: The Effects of Doping on the Behavior of Sol-Gel Entrapped Proteins

contributor:
Brennan, John D.
Chemistry

subject: effects, doping, behavior, Sol-gel, entrapped, proteins, biomolecules, glycerol, ligand

abstract: Research in the field of sol-gel derived materials has evolved dramatically over the past forty years. The developments in the past decade, in the field of bioanalytical chemistry, have revolutionized this field. Early research, as well as that done by our group, has confirmed that the commonly used alkoxysilane precursors (tetraethylorthosilicate - TEOS or tetramethylorthosilicate - TMOS) are not ideal for entrapment of biomolecules. They produce materials that are brittle, often undergo cracking due to hydration stresses and in some cases, can block the accessibility of the analyte to the entrapped biomolecules. My research project therefore focuses on the development of new sol-gel processing methods through the use of an additive-glycerol, which will produce new "second generation" glasses. I have focused on obtaining a basic understanding of glycerol-doped sol-gel derived materials and the effect they have on the entrapped biomolecules. Glycerol-doped sol-gel materials display larger pore size, decreased shrinkage and cracking as compared to the TEOS-based materials. Biocatalysts entrapped in glycerol-doped materials showed significantly smaller decreases in activity over a period of one month relative to enzyme entrapped in TEOS. Also, to gain further insight into the effects of glycerol doping on the properties of entrapped proteins, both steady-state and time-resolved fluorescence of Trp 214 was used to examine the conformation, dynamics, accessibility, thermal/chemical stability and the degree of ligand binding of human serum albumin (HSA) in solution and after entrapment of the protein in glycerol-doped TEOS-based materials.

abstract: Thesis

abstract: Master of Science (MSc)


title: Kinetics and Mechanisms of Carbonation Conversion of Aqueous Sodium Sulfide to Hydrogen Sulfide

contributor:
Lu, W-K
Metallurgy

subject: kinetics, mechanisms, carbonation, conversion, aqueous, sodium, sulfide, hydrogen, reaction, flow rate, gas

abstract:
 The objectives of the present study were to investigate the reaction mechanisms and the effects of certain physical variables on the overall reaction rate of the conversion of aqueous Na2S to gaseous H2S by bubbling with CO2 gas, which is a simultaneous absorption-desorption
reaction.

 The dependence of reaction rate on the physical variables investigated were the volumetric flow rate and the CO2 partial pressure of inlet gas and reaction temperature. Potential advantages of a pressurized reaction system were also studied. It was found that the effect of reaction temperature on the overall reaction rate was relatively
small as compared to that of inlet gas flow rate and CO2 partial pressure.

 Gas-liquid interfacial area was estimated and the overall reaction rate constant determined. It was found that the carbonation conversion of Na2S is first order with respect to both the HS- ion concentration of the liquid phase and the CO2 partial pressure of the inlet gas.

 The rate limiting step of the overall conversion reaction, under the present laboratory conditions, appeared to be the desorption of hydrogen sulfide.

abstract: Thesis

abstract: Master of Science (MSc)


title: A Hopeful Demise: A Biblical and Practical Theology of Exile for the Canadian Church Today

contributor:
Knowles, Michael P.
Boda, Mark J.
Christian Theology

subject: demise, biblical, practical, theology, exile, Canadian, church

abstract:
 This dissertation is an attempt to apply the motif of exile to the church in Canada today
and employ biblical resources to guide the church in its engagement with Canadian culture. At
one time the church held a place at the centre of Canadian life and contributed to the formation of national culture. As the nation has evolved, the role of the church has shifted significantly. The advent of secularization and a post-Christian, postmodern culture has moved the church from the centre to the margins of Canadian society. The proposal offered here is that this move can be understood as a form of exile. Exile is a rich motif in the history of the Christian faith. Our ancestors in the faith, the nation of Israel, were exiled by foreign nations. The Old Testament is, in many respects, a witness to that experience. Second Temple Jews continued to live under the authority of foreign powers and they also produced literature that testifies to their own sense of remaining in and responding to exile. The early church also understood itself as living in theological exile. The literature of the New Testament demonstrates how the first Christians sought to live faithfully while yet separated from their true, eschatological home. An understanding of exile in these texts and the theological approach that they offer can inform the church in Canada today as it also seeks to live faithfully in its particular contemporary context. This study seeks to engage the biblical materials with a view to applying their exilic wisdom to the life of the Canadian Church today. While the sociological demise of the church in Canada is now part of its historic narrative, exile can offer the contemporary church a paradigm for theological re-orientation, even as it did for Israel and the early church. Thus, adopting an exilic outlook and various aspects of a practical theology of exile can equip the Church in Canada with hope as it faces the challenges of its current circumstances.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Fractures and Fracture Filling in the Guelph Formation, Steetley Quarry Flamborough, Ontario

subject: fracture, filling, formation, Flamborough, Ontario, Guelph, rocks, minerals, stress, neotectonic

abstract:
 The North Quarry (north of Ontario Highway 4) is located in Flamborough Ontario. In it, rocks of the Guelph formation are well exposed. The Guelph formation consists of dolomite and at the North Quarry has an average thickness of 30m. These rocks are cut by three predominant joint sets which have no indication of shear motion. The 030° set was formed as a result of compaction and loading; It appears to represent an upward joint propagation mirroring the Algonquin Arch trend. Joint sets 120° and 160° are a north western analogue to the conjugate pair described by Nickelson and Hough (1967) in the north eastern United States.

 Vein data and sampled minerals, using techniques such as cathodoluminescence, photoluminescence, and isotope analysis enable paragenesis of joint propagation and crystallization relationships to be inferred. Possible stress field configurations have been deduced from these data. The joint set 030° was the first to open. Next, a minor east-west trending set opened. Joint sets 120° and 160° are the last to open. The joints were infilled by cement in the order of Organics > Calcite > Sulphides > Iron Oxides. Buckle heaves in the quarry were unreliable indicators of neotectonic stress.

abstract: Thesis

abstract: Bachelor of Science (BSc)


contributor:
Sassen, Bridgitte
Philosophy

abstract: title: The Provocations of Nihilism: Practical Philosophy and Aesthetics in Jacobi, Kant, and Schelling author:Jeremy Proulx location: Mills

abstract:
 The purpose of the dissertation is to describe how Friedrich Heinrich Jacobi's diagnosis
of nihilism at the heart of the rationalist metaphysics of the Enlightenment provokes a
tum to practical philosophy and aesthetics as alternative areas of philosophical scrutiny. I
divide my analysis into two basic parts, treating practical philosophy and aesthetics
respectively. The first part argues that Jacobi's debate with Moses Mendelssohn provokes
the development of two unique approaches to practical philosophy, Jacobi's and Kant's. I
interpret Jacobi's famous salto mortale as a balance between passively accepting feeling
as a legitimate revelation of truth and actively creating the practical context in which
feeling can appear as meaningful in the first place. I also argue that in his practical
response to the Jacobi-Mendelssohn debate, Kant is still susceptible to Jacobi's critique of
Enlightenment rationalism. In the second part, I tum my attention to how Kant and the
early Schelling both develop their aesthetic theories as a response to Jacobi's diagnosis of
nihilism. I show that Schelling's reinterpretation of Kant's theory of the postulates
subtlety introduces an aesthetic dimension to philosophy in the process of employing
Jacobian ideas to address problems in Kant. I continue on to interpret Kant's Critique of
Judgment as unified in its attempt to respond to Jacobi by accounting for the sensible
elements of experience as legitimate domain for philosophers. But I also argue that Kant's
unwillingness to see the world as a creative accomplishment of human reason ultimately
condemns his project to failure. I conclude by showing that Schelling's System of
Transcendental Idealism finally makes good on Jacobi's call to develop a philosophy that
accounts for the active role that agents have in the constitution of a meaningful world of
experience.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Fluorescently Labeled Sodium Hyaluronate: Synthesis, Characterization and Solution Properties

contributor:
Winnik, F. M.
Chemistry

subject: fluorescently, labeled, solution, sodium, hyaluronate, characterization, polymers, polarization

abstract: Fluorescence spectroscopy has been proven to be a useful technique for the investigation of the structural, physical and solution properties of polymers. A polymer system containing a photo physical probe can be investigated using fluorescence quenching and polarization. We have randomly labeled sodium hyaluronate (HA) chains with fluorescent dyes such as 1-(1-pyrenyl)methyl amine and N-ε-dansyl-L-lysine, and studied their physical, structural and solution properties, including interactions with surfactants using the above fluorescence techniques.

abstract: Thesis

abstract: Master of Science (MSc)


title: SIMULATION OF LARGE STRAIN BEHAVIOUR OF ZICONIUM-2 ALLOY

contributor:
Wu, Peidong
Mechanical Engineering

subject:
Large strain behavior
Zircounium alloys

abstract:
Zirconium is a widely applied material in nuclear industry and characterized by highly anisotropic mechanical behaviour. With the development of the nuclear industry, zirconium alloys have proven to be very important structural material used as pressure tubes in heavy water reactors, and thin-walled tubing in light water reactors due to improved corrosion resistance. To study the special property of zirconium, this thesis will evaluate different numerical models and will present an overview about the deformation mechanisms for zirconium alloys.

Twinning and De-twinning (TDT) and Predominant Twin Reorientation (PTR) models are both implemented in the EVPSC polycrystal model. Various self-consistent models as well as TDT and PTR twinning models are evaluated by studying large strain behavior of zirconium alloys slab under different deformation processes. The material parameters for those models are determined by virtue of the experimental uniaxial tension and compression along the normal direction (ND) as well as tension along the rolling direction (RD). The predictability of those models is assumed through comparison of macroscopic deformation behavior (stress strain curves and R values) and microscopic mechanical response (texture coefficients and lattice strain) between the predicted and experimental data. Numerical results reveal that, among the various models examined, the VPSC-TDT model with the Affine self-consistent scheme gives the best overall performance for zirconium alloys slab, TDT twinning model gives the better overall performance than the PTR twinning model.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Archean Crustal Evolution in the Barberton Mountain Land, South Africa: U-Pb and Nd Isotopic Constraints

contributor:
Davis, D. W.
Dickin, A. P.
McNutt, R. H.
Geology

subject: Archean, crustal, Barberton, mountain, land, isotopic, constraints, evolution, magmatic

abstract:
 New U-Pb ages from the Barberton Mountain Land document an 800 m.y. period of Archean magmatism (ca. 3540 Ma to ca. 2740 Ma) that can be divided into five distinct episodes. Magmatic activity during Episode I includes tonalite-trondhjemite gneisses such as the Steynsdorp pluton (3509 +8/-7 Ma) and a tectonically interleaved sliver (3538 +4/-2 Ma) located at the base of the Onverwacht Group. Trondhjemitic magmatism of Episode II is synchronous with volcanism and inferred D1 thrusting of the Onverwacht Group and is represented by plutons such as the Doornhoek (3448 ± 4 Ma), Theespruit (3443 +4/-3 Ma), and Stolzburg (3459 +5/-4 Ma). A quartz-feldspar porphyry dyke, related to Episode II, intrudes the Komati Formation of the Onverwacht Group and yields an age of 3467
+12/-7 Ma. D2-related thrusting, volcanism, sedimentation, and tonalitic plutonism in the north-central part of the Barberton greenstone belt (BGB) occurred during Episode III and are recorded by an ignimbrite which was deposited between the Fig Tree and Moodies Groups during regional deformation (3227 ± 1 Ma), by pre- and post-tectonic porphyries (3227 Ma), and by the emplacement of the Kaap Valley tonalite (3227 ± 1 Ma). Episode IV is characterized by the intrusion of large sheet-like potassic batholiths to the north and south of the BGB and syenitic plutonism at ca. 3107 Ma, and by D3-related deformation at the northern margin of the BGB. Gold mineralization also appears to coincide in time with this episode. The last known period of Archean magmatic activity in the BGB is represented by late phase granite magmatism at ca. 2740 Ma (Episode V).

 Epsilon Nd values range from +1.3 to -0.7 in rocks varying in composition from gabbro to granodiorite that were emplaced during Episodes I to IV. A gabbro from the Komati Formation, with a baddeleyite age of 3352 +6/-5 Ma, has an ϵNd of +1.3, which is the only value to fall on a depleted mantle growth curve. This value is similar to ϵNd data obtained by others for ca. 3450 Ma basalts from the Onverwacht Group. Three Episode IV plutons have identical ϵNd values of -0.5, and a granite pluton from Episode V has an ϵNd of -4.3, indicating a source compatible with remelting of older crust.

 In summary, the protracted evolution of the Barberton Mountain Land occurred in a series of discrete events widely separated in time. Each event is characterized by a number of geological processes (magmatism, volcanism, sedimentation) that appear to coincide in time with thrust-related deformation as a result of compressional tectonics. The duration of the main period of crustal growth occurred over ≈365 m.y. from ca. 3470 Ma, with the formation of the main Onverwacht sequence and its associated tonalitic-trondhjemitic rocks through ca. 3230 Ma, with the intrusion of the Kaap Valley tonalite and D2 thrust-related deformation, to ca. 3105 Ma, with the widespread emplacement of sheet-like potassic batholiths bordering the Barberton greenstone belt.

abstract: Thesis

abstract: Master of Science (MSc)


title: A Sigh of Mystery: Karl Barth's Theology of the Virgin Birth

contributor:
Widdicombe, Peter
Religious Studies

abstract: title: A Sign of Mystery: Karl Barth's Theology of the Virgin Birth, author: Dustin Resch, location: Mills

abstract: In this study, I examine Karl Barth's doctrine of the virgin birth of Christ in relation to his discussions in the Church Dogmatics of Christology, pneumatology and interpretation of Scripture. I argue that the virgin birth of Jesus Christ is understood by Barth as a fitting sign to expresses the form of the dialectic of God's "No" to sin and "Yes" to humanity in his free act of revelation and reconciliation. As such, the doctrine of the virgin birth functions for Barth as a paradigm through which to understand the fashion of God's work upon human beings and the suitable posture of a human being before God. I demonstrate this conviction by providing an overview of select interpreters of the doctrine of the virgin birth in the western Christian tradition in order to set Barth's contribution in its theological context. I then provide an exposition of the methodological and exegetical features of Barth's development of the doctrine of the virgin birth from his first professorship up to the introductory volume of the CD. Next, I examine how Barth's doctrine of the virgin birth fit with his broader Christology and pneumatology as represented in the CD. Finally, I provide an exposition of Barth's treatment of the figure of Mary as a capstone to the themes previously outlined. The thesis concludes with a series of probing questions about the implications of Barth's doctrine of the virgin birth for his broader theology.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Variation in tree and shrub diversity across space, along environmental gradients and through time in a temperate forest in eastern North America

title: Forest diversity across space and environmental gradients

contributor:
Dudley, Susan
Biology

subject:
forest dynamics
carolinian forest
eastern temperate forest
spatial structure
environmental gradients
forest plot
variation partitioning
community assembly

abstract: The variation in community composition among sites is often used to gain insight into the processes of plant community assembly. In this study, we looked for evidence of environmentally and spatially mediated community assembly mechanisms in a temperate forest in eastern North America. To test this, we measured, identified and mapped all woody stems ≥1 cm in diameter at breast height (DBH) in 12 ha of a 20 ha forest plot. We used principal coordinates of neighbor matrices (PCNM) to obtain variables that modelled spatial processes (eg. dispersal, drift) at the community level. Topographic variables (slope, elevation, convexity, aspect) were used to model environmental conditions. Variation partitioning was used to isolate the unique and shared effects of topographic and spatial variables on community composition. We were also interested in studying how associations with the environment change with tree size. For this we assessed the abundance of a subset of focal species in response to topography as well as human disturbance. Species abundance were divided into three stem size classes: small (< 5 cm), medium (≥5 cm and < 15), and big (≥15 cm). We found that topography and space jointly explained 63% of the variation in community composition. This variation was almost entirely spatially structured with the component of pure topography only contributing 1% to the total explained variation. A redundancy analysis showed that slope and elevation were the most important topographic variables structuring the distribution of trees. The focal species had largely independent distributions across the environmental gradients and three of the five species showed within-species differences associated with size class effects on the relationship with topography and human disturbance. The implications of these results are relevant to conservation efforts and suggest that large contiguous areas of heterogeneous environments are essential in maintaining biodiversity.

abstract: Thesis

abstract: Master of Science (MSc)


title: Optimization of the Prompt Gamma Site at the McMaster Nuclear Reactor for in Vivo Neutron Activation Analysis

contributor:
Chettle, David
Medical Physics

subject: optimization, gamma, site, nuclear, reactor, neutron, activation, analysis, cadmium

abstract:
 This work was the first study at the beam port # 4 at the McMaster Nuclear
Reactor, involving prompt gamma in vivo neutron activation analysis. The project
consisted of experimental and computational parts. The computational part was done
using MCNP program, which simulates the neutron and photon transport in the medium.
The first thing assessed was the energy dependent neutron fluence rate in the collimated
neutron beam, at the site. This was done in order to figure out the complete source (sdef)
card for further MCNP calculations. This was combined experimental and computational
work. For the experimental part, various activation foils were used and computational
part was done by using MCNP programming.

 The second part of the project involved experimental prompt gamma in vivo activation analysis using 7 different phantoms, ranging from 30 mL to 2 L. Three different elements were observed. The prompt gamma in vivo detection of cadmium was the preliminary calibration study and the experiments were done with all seven phantoms. The calibration lines and MDL were assessed for all phantoms, with concentration ranging from 0 to 50 ppm. The prompt gamma in vivo detection of boron and mercury was done using 30 mL phantoms. Calibration lines and MDL for both elements were assessed as well.

 MCNP experimental simulations for 30 mL water phantoms were done and they were in close agreement with the experimental results. Furthermore, the MCNP gamma and neutron dose survey in the cave was done.

 The results obtained showed that there are numerous open possibilities for improvement in terms of in vivo prompt gamma analysis at the site. It predominantly includes the improvements in prompt gamma detection techniques and MCNP source definition. Furthermore, it was found that MCNP programming is the ideal tool for assessment and control of the experimental results in this case. It means that in the future research, the MCNP modeling will be the essential part of the in vivo prompt gamma activation analysis at this beam port.

abstract: Thesis

abstract: Master of Science (MSc)


title: Meshless Dynamic Relaxation Techniques for Simulation Atomic Structures of Materials

contributor:
Metzger, D. R.
Niewczas, M.
Mechanical Engineering

subject: meshless, dynamic, relaxation, techniques, simulating, atomic, structures, materials, defects

abstract:
 Traditionally, Molecular Dynamics combined with pair potential functions or the Embedded Atom Method (EAM) is applied to simulate the motion of atoms. When a defect is generated in the crystalline lattice, the equilibrium of atoms around it is destroyed. The atoms move to find a new place where the potential energy in the system is minimum, which could result in a change of the local atomic structure. This thesis introduces a new Dynamic Relaxation algorithm, which is based on explicit Finite Element Analysis, and pair or EAM potential function, to find equilibrium positions of the block of atoms containing different structural defects.

 The internal force and stiffness at the atoms (nodes) are obtained by the first and second derivatives of the potential energy functions. The convergence criterion is based on the Euclidean norm of internal force being close to zero when the potential energy is minimum. The damping ratio affects the solution path so that different damping ratios could lead to different minimum potential energy and equilibrium shapes. The choice of scaled mass of atoms, proper time step, boundary conditions and damping appropriate for the efficient and stable simulation is studied.

 A small block of atoms is used to obtain the numerical responses from a hybrid algorithm of potential energy functions and Dynamic Relaxation techniques such as repulsion and attraction in pair potential, minimum configuration, damping effects and different boundary conditions.

 The simulation using modified Dynamic Relaxation techniques is performed to the
real material model with dislocation defect. The results after relaxation are in agreement
with the prediction and current Molecular Dynamics simulation. Therefore, Dynamic
Relaxation could be an alternative tool for atomistic simulation.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Indigenous Cosmology in Global Contexts: A Remediation of the Paradigm of Sustainable Development in Natural Resource Extraction Policies

contributor:
O'Brien, Robert
Political Science

subject:
Indigenous politics
Cosmology
Sustainable development
Natural resources
Extraction
North-South Relations

abstract: The project of sustainable development has been a guiding principle in international economic and political relations for decades. Though promising progress and the eradication of poverty, while securing the environment, the development project has come at a significant price in terms of environmental degradation and the erosion of domestic norms and identities. Thus, there is a clear tension between the goals and outcomes of the historical trajectory of the development discourse which provides great insight into global North-South relations. The paper has two simultaneous aims of the paper. The first is to investigate the nature of the Western paradigm of sustainable development in natural resource extraction and interrogate its supposed commitment to fostering economic growth while simultaneously supporting environmental sustainability. The application of a Foucaultian lens, with the incorporation of key concepts such as governmentality and regimes of truth, functions to recover subject positions of the discourse. First, the Northern position of power and truth dissemination and second, the Southern actors whose beliefs disappear through the identity ascription inherent to the Western notion of sustainable development. Finding the cosmopolitan foundations of sustainable development to be fictitious, the paper then develops to the second aim of the paper: the possibility of alternative frameworks of natural resource extraction, finding value within the institutionalization of indigenous cosmologies and traditional knowledges in development governance at the local and global level.

abstract: Thesis

abstract: Master of Arts (MA)


title: Synthesis and Nuclear Magnetic Resonance Studies of the Tetrakis (Tri-Para-Tolyl Phosphite) Nickel (0) Hydride System

contributor:
Eaton, D. R.
McGlinchey, M. J.
Chemistry

subject: synthesis, nuclear, magnetic, resonance, phosphite, nickel, hydride, system, acids, reactions, species, fluxional, molecule, ligands

abstract:
 This thesis is primarily concerned with an investigation of the reaction of tetrakis(tri-p-tolyl phosphite)nickel(0) with strong acids, using 1H, 31P and 2H NMR. The results differ from those previously obtained for similar reactions with other Ni(0) phosphites, in that both five and four-coordinate nickel hydrides are formed in concentrations sufficient for spectroscopic studies. The four-coordinated hydride is believed to be the catalytically active species in a number of reactions catalyzed by Ni(0) phosphites. Variable-temperature studies show that the four-coordinate hydride complex is a fluxional molecule. The exchange process is exclusively intramolecular in nature.

 A very simple method was used to analyze the NMR data and obtain activation parameters for the exchange process. These parameters were compared with those reported in the literature for related intramolecular and intermolecular reactions. The large negative entropy of activation is interpreted in terms of ion pairing in the transition state. NMR evidence for the structure of the products resulting from the reactions of acids with both the metal complexes and the free phosphite ligands is presented. The conditions necessary for the observation of four-coordinated nickel hydrides are also discussed.

abstract: Thesis

abstract: Master of Science (MSc)


title: Model-Based Predictive Control for Improving Stability and Transparency in Time-Delay Teleopertation

contributor:
Sirouspour, Shahin
Electrical and Computer Engineering

abstract: Title: Model-Based Predictive Control for Improving Stability and Transparency in Time-Delay Teleopretation, Author: Ali Shahdi, Location: Mills

abstract:
Prior research on time-delay bilateral teleoperation has mainly resulted in methods
that favor the robust stability of the system at the expense of its transparency.
In contrast, it is demonstrated in this thesis that carefully designed model-based
predictive controllers are able to achieve high levels of transparency while maintaining
teleoperation stability. This is accomplished by utilizing available information
on system model and time delay within a predictive control framework. The
performance objectives are delay-free position tracking between the master and
slave and the establishment of a virtual mass-damper tool impedance between the
user and environment. Three model-based predictive controllers are proposed in
this thesis which utilize both force and position measurements at the master and
slave sites. The first two controllers can only handle known and fixed time delays
whereas the third controller is applicable to systems with fixed or variable delay.

First, building upon our recent work in [1, 2], a decentralized model-based
predictive controller is introduced that can enhance the time-delay teleoperation
transparency and robust stability by allowing the use of local delay-free measurements
in local master I slave controllers. The stability of the system is analyzed
using a frequency sweeping test. Numerical analysis demonstrates improved performance
and robustness compared with the centralized controller in [2].

Next, a robust predictive controller is proposed to deal with modeling uncertainty,
particularly in the operator and environment dynamics. In a two-step control
approach, first local adaptive/nonlinear controllers are applied to linearize the
system dynamics and to eliminate dependency on the master and slave parameters.
Teleoperation coordination is then achieved by formulating an input/ output
(I/O) time-delay H00 robust control synthesis. The transparency and robust stability
properties of the proposed method are examined via numerical analysis.

Although less sensitive to modeling uncertainty, the robust controller can still
sacrifice teleoperation transparency in favor of its stability since it utilizes a fixed
controller for the entire range of teleoperation. In an attempt to avoid such a tradeoff,
a stable adaptive predictive controller for teleoperation systems with constant
and varying communication delay is proposed. The controller utilizes a model of
the system dynamics and the time delay within a predictive control framework to
achieve the desired transparency objectives while maintaining the system stability.
The controller adapts to uncertainties in the system dynamics by estimating
the model parameters in real time. A Lyapunov analysis of the performance and
stability of the resulting system is presented.

The proposed controllers for time-delay bilateral teleoperation are implemented and experimentally evaluated. The results demonstrate the effectiveness of the proposed methods in providing a stable transparent interface for teleoperation under time delay.

abstract: Thesis

abstract: Doctor of Engineering (DEng)


title: Complex mode theory and applications in silicon photonics

contributor:
Li, Xun
Huang, Wei-ping
Electrical and Computer Engineering

subject:
Silicon photonics
Frequency domain simulation method
Complex mode theory

abstract:
Silicon photonics has witnessed rapid development in recent years for its fabrication compatibility with the cost-effective CMOS technology. The advancement of relevant simulation tools, however, is at a relatively slow pace. The high index contrast of the usual silicon waveguide that has imposed new challenges to the convergence and accuracy of the solution technique, the growing intricacy in solitary component design, and the increased complexity of their integration, are the impelling factors that motivate us to improve the computer-aided design, modeling, simulation, and optimization methods.
The theme of the thesis is on the frequency domain simulation methods supported by the complex mode theory. The complex mode theory is introduced to the simulation domain truncated by the perfectly matching layers (PMLs) enclosed in the perfectly reflected boundaries (PRBs), wherein the discrete complex modes as eigen solutions can represent the continuous radiation fields, thus yields a unified approach for handling both guided (discrete) and radiation (continuous) waves.
In this thesis, theoretical investigations have been conducted along a few different lines aiming at improving the efficiency and accuracy in complex mode expansion. Properties of high-order complex Berenger modes are firstly addressed through asymptotic solutions, and it is found that as the mode order increases, the symmetry of the cladding and substrate in the simulation domain, instead of the guiding schemes, plays a more and more decisive role regarding mode classification and modal field distribution. A weighed optical path method is then proposed to unify the high-order Berenger modes, and to enhance the symmetry of high order modes’ field distributions in the asymmetric structures, leading to the improvement in convergence speed and stability in the mode expansion. Next, an improved mode-matching method (MMM) is proposed based on an error-minimizing method instead of the conventional approach relying on the unreliable modal orthogonal property. The newly proposed method is significantly more robust as numerical errors usually jeopardize the modal orthogonality. This claim is exemplified by simulation results on silicon channel waveguide facet, bending waveguide, and silicon-germanium photo-detector waveguide.
As a direct application of the improved complex mode theory, a hybrid plasmonic-photonic nano-ribbon waveguide is proposed, standing as a combination of the silicon slot and surface plasmon polariton (SPP) waveguides, is proposed and analyzed. We have found that the fundamental mode is featured at low loss as in optical waveguide as well as high confinement as in plasmonic structure. Simulations have shown that millimeter range propagation can be sustained with strong confinement. We have further studied such waveguide with an extra layer of phase changing material incorporated, attempting to realize the efficient electro-optical phase and/or loss modulation. Finally, an optical switch design is proposed by taking the full advantage of the aforementioned structure.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


contributor:
Haykin, Simon
Computational Engineering and Science

abstract: Title: Dynamic Models of Cognitive Radio Networks, Author: Peyman Setoodeh, Location: Mills

abstract:
A cognitive radio network is a multi-user system, in which different users compete for
limited resources in an opportunistic manner, interacting with each other for access
to the available resources. The fact that both users and spectrum holes (i.e., underutilized
spectrum subbands) can come and go in a stochastic manner, makes a cognitive
radio network a highly dynamic and challenging wireless environment. Finding
robust decentralized resource-allocation algorithms, which are capable of achieving
reasonably good solutions fast enough in order to guarantee an acceptable level of
performance even under worst-case interference conditions, is crucial in such an environment.

Considering a non-cooperative framework, the iterative waterfilling algorithm
(IWFA) is a potentially good candidate for transmit-power control in cognitive radio
networks for achieving a Nash-equilibrium point. IWFA is appealing because of its
low complexity, fast convergence, distributed nature, and convexity. It can be reformulated
as an affine variational inequality (AVI) problem. Employing the theory of
projected dynamic (PD) systems, an affine dynamic model is obtained for the evolution
of the network's state. This dynamic model allows us to study both equilibrium
and disequilibrium behaviour of the network. The proposed dynamic framework also
facilitates sensitivity and stability analysis of the system.

The fact that changes happen in a cognitive radio network because of continuous dynamics as well as discrete events, makes it a hybrid dynamic (HD) system. Decision making is then a multiple-time-scale process. Modeling the system using the theory of PD lends itself to describing the cognitive radio network as a constrained piecewise affine (PWA) system and therefore, benefiting from various mathematical tools, which have been well demonstrated in control theory.

Usually users use asynchronous update schemes and they update their transmit
powers at different rates. The feedback channel introduces a time-varying delay in the
control loop of a cognitive radio, which means sometimes users update their transmit
powers using out-dated information. Therefore, the network is practically speaking
a multiple-time-varying-delay system with uncertainty. Robust exponential stability
of the network is studied in this framework.

Theories of evolutionary variational inequalities and projected dynamic systems on Hilbert spaces were used to extend the developed framework further in order to address the multiple-time-scale nature of the cognitive radio network.

abstract: Thesis

abstract: Doctor of Engineering (DEng)


contributor:
Heckette, Rick D.
Business Administration

abstract: Title: The Effects of Perceptions of Situational Strength in HR Practices on Job Attitudes and Business Unit Performance, Author: Mark G. Podolsky, Location: Mills

abstract:
Building on the work of Ostroff and Bowen (2000; 2004) and using situational
strength theory (Mischel, 1976) and the Attraction-Selection-Attrition model (Schneider,
1987), this study measures the degree to which employees perceive HR practices to
contribute to situational strength around strategic organizational goals (HR Strength).
The effect of these HR practice perceptions is examined on individual-level job
satisfaction, affective commitment, organizational citizenship behaviour (OCB), turnover
intentions, and business-unit service climate and performance. Data were collected from
274 full-time managers at 82 work sites within an assisted-living organization.
Hierarchical linear modeling (HLM) was used to assess individual effects of HR Strength
on attitudes and OCB as well as group level effects of HR Strength on individual
attitudes. OLS regression was used to test the group level effects of HR Strength on
group climate, financial performance, and lost hours due to injury. Results show that
perceptions of HR Strength at the individual level associate positively with job
satisfaction, affective commitment, OCB, and turnover intentions (negatively) and
positively at the group level with global service climate and financial performance, and
negatively (marginal, p<.1) with lost hours due to injury. These findings contribute to an
emerging body of literature on the effects of group homogeneity in organizations. They
demonstrate that organization structures contribute to the emergence of human capital at
the group level. They also show that HR practices contribute to organizational
performance and service climate when employees are in agreement in perceiving them as
reinforcing situational strength around organizational goals.

abstract: Thesis

abstract: Doctor of Business Administration (DBA)


contributor:
Higgs, Paul G.
Physics

abstract: Title: Codon Usage Bias, tRNA Modifications and Translational Selection in Bacteria, Author: Wenqi Ran, Location: Mills

abstract:
In this thesis, codon usage bias is studied in a large number of bacterial genomes.
The codon frequency of each codon is measured as a fraction of the total number of
codons for each amino acid, which can be used to calculate the potential selection
strength in a genome according to the population genetics theory of selection, mutation
and drift. It is assumed that codon frequencies in low expression genes are affected
principally by mutation rates, but the frequencies in high expression genes are controlled
by both selection and mutation. The ribosomal protein genes and elongation factors are
used as high expression genes, while the rest as low expression genes. By comparing the
frequencies of codons in high and low expression genes, we can determine the strength of
selection acting on high expression genes. A model of translation kinetics is developed,
which predicts the way that the speed of translation of each codon depends on the number
of copies of each type of tRNA gene in the genome. This theory reveals that codon usage
and tRNA gene copy number have to co-adapt to each other to optimize the speed of
translation. We show that there are often multiple possible stable combinations of tRNAs
and codon usage. This explains the observation that different codons are sometimes
preferred for different amino acids in the same organism.

We compare our theory with observed codon frequencies in a large number of bacterial genomes. Codon families are grouped according to different combinations of tRNAs and the averages of codon frequencies for all combinations are taken respectively. A preferred codon is defined as the codon whose frequency increases from low expression genes to high expression genes. The interesting phenomenon is that the anticodon-codon interactions are different between two-codon families (the U+C and A+G codon families) and four-codon families, mainly because of the tRNA modifications on position 34 of the tRNA anticodon loop. We show that the preferred codon depends on which base is present at wobble position and whether a base modification happens. It is found that the preferred anticodon-codon combinations do not always correspond to Watson-Crick pairs. In particular, in four-codon families, tRNAs with U at the wobble position appear to interact surprisingly well with U-ending codons.

We introduce a parameter, K, which measures the strength of codon bias in each genome. We show that K is strongly correlated with the growth rate of the organism. This is consistent with the idea that selection for translational speed is most important for rapidly multiplying organisms. From the theory, the effective population size Ne is also expected to influence the selection strength. However, our data analysis shows that K is not correlated with Neu. This shows that variation of Neu among species is not a confounding factor in our interpretation.
Although we believe that translation speed is the main reason for selection on codon usage in bacteria, it is also possible that selection for translational accuracy plays a role. Selection for accuracy can be tested by comparing codon frequencies in conserved and variable sites within the same gene sequences. We introduce a new statistical test to measure the strength of this effect. We observe a small but significant effect of accuracy with this method.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


contributor:
Yuan, Yufei
Business Administration

abstract: Title: Information Systems Security Misbehaviour in the Workplace: The Effects of Job Performance Expectation and Workgroup Norm, Author: Ken Huijin Guo, Location: Mills

abstract:
Information systems (IS) security has become a major current issue for
organizations. It is generally understood that not only technology but also human factors
and control processes have a significant impact on organizational IS security. One of the
major human factors issues is end user behavior towards IS security. End users may
ignore security measures and by doing so they inadvertently put the organization's
information at risk. This study investigated why end users engage in such "security
misbehavior" (SMB). Based on Eagly and Chaiken's composite behavioral model, an
SMB model was proposed and tested empirically with data collected from a survey of
computer end users in the workplace (N=306). Overall, the theoretical model was
successful in capturing the main antecedents of end user SMB intention. Both attitude
towards SMB and workgroup norm were found to have significant positive influences on
SMB intention. In tum, attitude towards SMB is positively influenced by workgroup
norm and job performance expectation. Contrary to the hypotheses of the model,
however, user attitude towards the target (attitude towards security policy) and several
utilitarian outcome expectations (perceived security risk, perceived accountability, and
sanction certainty) did not have significant influences on end user attitudes towards SMB.
However, asymmetric effects were discovered among these variables. Furthermore, the
influences of self-identity outcome expectation (perceived identity match) on both
attitude towards SMB and behavioral intention were not significant. The results also
indicated that end user SMB intentions are to some extent dependent on the context. In sum, the findings suggest that job performance expectation and workgroup norm are key
determinants and have strong direct and indirect effects on user SMB intention.

abstract: Thesis

abstract: Doctor of Business Administration (DBA)


contributor:
Alsop, James D.
History

abstract: Title: Healing the 'African Body' in the Age of Abolition? British Medicine in West Africa, circa 1800-1860, Author: John Rankin, Location: Mills

abstract:
This investigation provides an in-depth examination of British and African
interactions in British West Africa within the field of health and medicine, circa 1800-
1860. It examines how Britons perceived, created, and understood Africans and their
bodies during a period of extensive and significant change. This assists our
understanding of one of the historical roots of racialized medicine, provide insight into
British perceptions of and interaction with overseas peoples, and illuminates how Britons
developed or expanded notions about Africans, their bodies, and their health during a
relatively neglected period for relevant scholarship. It also examines African responses to
European medicine in a variety of contexts. In order to gain a clearer understanding of
the intersection of race and medicine during this period, the study examines how leading
theorists of race formulated and constructed the African body, explores how missionaries
from the Church Missionary Society and Wesleyan Methodist Missionary Society
understood health and medicine, examines the British medical system established in West
Africa and particularly the ways in which it handled the care of liberated Africans, and
studies the health of European and African personnel in the armed forces stationed in
West Africa. The thesis emphasizes the multiplicity both in forms of medical practice
and in approach to ' the African body. '

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Synthesis of Short, Self-Complementary DNA Oligomers and Solution Studies of their Duplex Structure and Formation

contributor:
Neilson, Thomas
Biochemistry

subject: synthesis, DNA, oligomers, solution, duplex, structure, formation, phosphotriester, temperature

abstract:
 A phosphotriester synthesis for short deoxy oligomers was developed based on the RNA synthesis developed in Neilson's laboratory. This synthesis parallels that of Catlin and Cramer (1973) but differs significantly in a number of procedures and reagents used and represents an overall improvement in every aspect of the previous method. This synthetic procedure allows the synthesis of sufficient quantities of DNA for 1H-NMR analysis. The following
sequences were successfully synthesized using this procedure:
d(GCA)
d(AGCT)
d(ACGT)
d(ACGTp)
d (ACGTACGTp).

 It was found by variable temperature 1H-NMR that the trimer and the tetramer duplexes had a very low Tm (0-10°C) as compared to their RNA counter-parts which had Tms between 29-34°C. This demonstrates quantitatively that the short DNA
duplex is significantly less stable than the short RNA duplex. Consequently, sequences of at least five or six bases in length will be required for model studies of DNA duplex stabilities using variable temperature NMR methods.

 A CD study of d(ACGTACGTp) in conditions of low salt (1M NaCl) and high salt (5M NaCl) demonstrated that a high salt B to Z-helix transition did not occur. Instead, the duplex remained in the right handed B form in both low and high salt.

abstract: Thesis

abstract: Master of Science (MSc)


title: Optimizing the Methodology for Measuring Supraclavicular Skin Temperature for the Detection of Brown Adipose Tissue in Adult Humans using Infrared Thermography

contributor:
Steinberg, Gregory
Medical Sciences

subject: Brown adipose tissue, infrared thermography

abstract:
Abstract

Background: The discovery of brown adipose tissue (BAT) in adults has sparked interest in its role as a therapeutic target in metabolic disorders. Preliminary studies have indicated that infrared thermography may be a promising way to quantify this thermogenic organ, which in humans is located primarily in the supraclavicular area and is activated by cold. However, ways to standardize infrared thermography methodology and to ensure measurements are reproducible have not been established.

Objective: This study aims to establish a standardized and reproducible protocol to measure a thermal response to cold in the supraclavicular area.

Method: In phase 1 of the study, thermal images of the supraclavicular area were taken on 3 occasions in 28 healthy adult males with mean age 23.95 ±5.87 years and mean BMI 25.20 ±3.93 kg/m2 who demonstrated a 100kcal/d increase in energy expenditure when exposed to 12ºC; a temperature known to increase BAT activity without shivering. During the first and second visits, participants were acclimated for 1 hour at 32ºC  and room temperature (20-23ºC) respectively, followed by a 1 hour period of torso cold exposure at 12ºC using a cooling blanket. The third visit consisted of taking thermal images at room temperature over two hours. Body composition was measured with DEXA scanner. In phase 2, 3 trials of 32ºC acclimation followed by 12ºC cold exposure (32ºC-cold) were studied in 14 healthy adult males (mean age 20.93 ±2.4 years and mean BMI 23.55 ±3.15 kg/m2) for repeatability. The outdoor temperature on the morning of each visit was recorded from the website http://climate.weather.gc.ca in both phases.

Results: In phase 1 the supraclavicular temperature stabilized after 45 minutes of acclimation at 32ºC and then rose abruptly with cooling, plateauing at 10 minutes. The change in supraclavicular temperature in response to cooling was greater after 32ºC compared to room temperature acclimation (0.22 ±0.19 vs 0.13±0.17ºC, p=0.053). There was no relation between outdoor temperature on the morning of the visit and the 32°C-cold thermal response (r=-0.18, p=0.14). The 32ºC-cold thermal response did not correlate with cervical and supraclavicular fat in 25 young males with BMI between 19.3-32.3 kg/m2 (r=-0.26, p=0.21). In phase 2, the thermal response after 32ºC acclimation was reproducible [intraclass correlation coefficient of 0.69 (0.14-0.72)].

Conclusion: Acclimation at 32ºC produces a greater and earlier response to cold in the supraclavicular area than room temperature acclimation. The thermal response after 32ºC acclimation is reproducible and unlikely to be affected by outdoor temperature and subcutaneous fat in the neck. These data suggest that the use of infrared thermography using the 32ºC-cold protocol may be effective for detecting the metabolic activity of brown adipose tissue.

abstract: Thesis

abstract: Master of Science (MSc)


title: Living Polystyrene Anions Terminated with Difulvene

contributor:
Stöver, Harald D. H.
Chemistry

subject: living, polystyrene, anions, difulvene, polymerization, macromolecule, functional groups, nuclear, magnetic

abstract: This project proposal is focused on the development of a novel class of Viscosity Index improvers. A bench-top method for living anionic polymerization has been set up and tested in many aspects. A new difulvene derivative, 1,4-di(6'-6'-methyl-fulvyl)benzene, was synthesized. The living anionic polymer chain was terminated on this difulvene. Cyclopentadiene groups were formed in the middle of the macromolecule chain during the termination. A doubled molecular weight of polystyrene was obtained after the termination. The cyclopentadienes were then changed to other functional groups by Diels-Alder reaction with dimethyl acetylenedicarboxylate, ozonolysis of double bonds, and bromination and reaction with amine. The infrared spectra and nuclear magnetic resonance spectra of the resulting polymers showed new peaks for the new attached groups.

abstract: Thesis

abstract: Master of Science (MSc)


title: The Evolution of Gemomic and Non-Genomic Regulatory Mechanisms o fMitochondrial Lipid Oxidation in Fish

contributor:
McClelland, Grant
Biology

abstract: Title: The Evolution of Genomic and Non-Genomic Regulatory Mechanisms of Mitochondrial Lipid Oxidation in Fish, Author: Andrea J. Morash, Location: Mills

abstract:
Research in the field of lipid metabolism has blossomed in recent decades,
particularly in terms of human metabolic disease. This has been studied mostly in
mammals despite the importance of lipid metabolism on the energetics and life history of
non-mammalian vertebrates such as fish. Fish have a large ecological and economic
impact but have received little attention in the area of lipid metabolism. The main goal of
my thesis is to understand the regulatory mechanisms which control lipid oxidation in fish
under changing physiological conditions. In particular, I investigated the regulation of
carnitine palmitoyltransferase (CPT) I, an enzyme which controls the entry of fatty acids
into the mitochondria for oxidation. To accomplish this, I first examined the function and
regulation of CPT I under routine conditions in liver and muscle tissue of rainbow trout.
The results indicated that the expression, function and regulation of CPT I was variable
across tissues. A phylogenetic reconstruction revealed multiple CPT I isoforms arising in
fish after diverging from mammals highlighting the need for future tissue and species
specific investigations.

With this fundamental knowledge, I was able to determine the effects of dietary
manipulations and fasting on genomic and non-genomic CPT I regulation in rainbow
trout. I found that changes in dietary fatty acids mainly effect the genomic regulation of
CPT I through changes in the expression of CPT I and its transcription factor, PPAR.
Fasting also induced increases in PP AR expression and further, caused a reduction in
CPT I sensitivity to its inhibitor, malonyl-CoA, resulting in higher CPT I activity and
rates of fatty acid oxidation.

In a final comparative study, I investigated the individual effects of endurance
exercise on muscle fatty acid oxidation in rainbow trout and the combined effects of
endurance exercise and fasting in a natural population of migrating pacific salmon. I
found that changes in the activity of several lipid oxidation enzymes in red muscle during
exercise were not as great as those found in the initial stages of migration in salmon.
Similarly, changes in CPT I mRNA expression were greater in migrating salmon than in
exercised trout. In contrast, changes in the mRNA expression of metabolic regulators and
transcription factors were similar in both exercising trout and migrating salmon.
This thesis has significantly advanced our knowledge of lipid metabolism in fish
and has highlighted the need to future research in this area.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Regional Jointing Pattern Within the Surficial Glacial Sediments and Bedrock of South-Central Ontario

contributor:
Eyles, C. H.
Geography

subject: regional, jointing, pattern, surficial, glacial, sediments, bedrock, industrial waste, disposal

abstract: There is mounting pressure to find suitable disposal sites for both household and industrial waste in south-central Ontario as a solution to Metropolitan Toronto's growing 'garbage crisis'. New data indicate that the fine-grained glacial sediments of south-central Ontario, previously considered to be 'tight' and impermeable, are in fact penetrated by an extensive joint system. This thesis provides basic information regarding the regional character, orientation and origin of joints within the surficial glacial sediments and bedrock of south-central Ontario. Three regional joint sets can be identified. Within the bedrock, the joint sets are oriented northeast/southwest, northwest/southeast and north/south. This trend is consistent with the regional jointing pattern within the overlying glacial sediments and suggests that the joints may have propagated from the bedrock into the glacial sediments. A comparison between the regional jointing pattern identified in bedrock and glacial materials and the orientation of stress release structures suggests that the regional pattern of jointing is controlled by the regional stress field which results from intraplate tectonic stresses. However, the orientation of joints at any individual site may also be controlled by 'local' factors such as face orientation, direction of glacial ice movement and lithology and by randomly oriented joints formed as the result of physical and chemical weathering, synaeresis, subglacial deformation and stress relief. The identification of regional jointing pattern within south-central Ontario allows the prediction of joint characteristics and orientations at potential landfill sites in the region, critical to the accurate evaluation of the permeability of the substrate materials.

abstract: Thesis

abstract: Master of Science (MSc)


title: A STUDY OF POROUS ELECTRODES FOR DNA ELECTROCHEMICAL DETECTION AND THE DEVELOPMENT OF A HYBRIDIZATION EFFICIENCY CHARACTERIZATION TECHNIQUE

contributor:
Soleymani, Leyla
Engineering Physics

subject: Biosensors Electrochemical DNA rapid-prototyping point-of-care

abstract:
Point-of-care DNA diagnostics for resource-limited settings require high sensitivity and low limits of detection but is constrained by a limitation on the complexity of instrumentation and resource consumption. To assist in the research and development of such technology, rapid-prototyping offers quick turnaround times from ideation to proof-of-concept testing at reduced costs.
All-solution processed electrodes which exhibit micro/nano-scale wrinkling and porosity were rapidly-prototyped. Probe density was shown to be tunable with these electrodes and densities were greater than planar electrodes due to a surface area enhancement. Such electrodes also demonstrated favorable characteristics for the electrocatalytic detection of DNA hybridization.
Characterization of hybridization efficiency for DNA biosensors often require the determination of probe and target DNA densities in separate experiments, relying on averaged measurements which lose device specificity. A new method to quantify hybridization efficiency was developed which allows the label-free, sequential determination of probe DNA and target DNA density in one experiment, allowing electrode-specific characterization of hybridization efficiency.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Tuning the properties of in situ gelling POEGMA hydrogels by controlling precursor polymer molecular weight and structure

contributor:
Hoare, Todd
Biomedical Engineering

abstract: Injectable hydrogels made from synthetic polymers represent a versatile class of biomaterials that have been extensively investigated for their potential application as drug delivery vehicles and tissue engineering scaffolds, due to their ease of in vivo delivery, high tuneability, and across-linked hydrophilic network structure that has mechanical and chemical similarities to native tissues. In the case of injectable hydrogels that are formed via covalent bonds between synthetic polymers, hydrogel properties can often be tuned by chemical modification of the precursor polymers. However, changing the chemistry of a hydrogel system can often have unforeseen or unintended consequences in terms of factors such as drug partitioning or how cells interact with the hydrogel substrate. There is a need, therefore, for devising alternative methods to modulate the properties of hydrogels while maintaining chemical uniformity within the gels. This thesis investigates two methods for modulating the properties of poly(oligoethylene glycol methacrylate) (POEGMA) based injectable hydrogels that work by changing the structural characteristics of the POEGMA precursors while maintaining uniformity of chemical factors such as functional group distribution. POEGMA is a widely used synthetic poly(ethylene glycol) analogue that has a number of beneficial properties including being biodegradable, non-cytotoxic, and readily functionalizable. In the first method, the properties of POEGMA-based hydrogels were modulated by changing the molecular weight of the POEGMA precursors that were used to form the gels. Well-defined functionalized POEGMA polymers of various molecular weights (with complementary hydrazide/aldehyde functionalities) were prepared using RAFT polymerization, and the polymers were subsequently mixed to form hydrogels in situ via rapid formation of hydrazine bonds. These gels were assessed to determine how polymer molecular weight affects properties such as mechanical strength, swelling/degradation, and gelation kinetics. In the second method, hyperbranched POEGMA polymers were prepared by inclusion of a di-vinyl cross-linker into the RAFT polymerization of these polymers. A series of functionalized polymers was prepared by varying the degree of branching in the polymers, with the properties of these polymers subsequently investigated to determine how branching degree affected polymer properties. The polymers were then demonstrated to be capable of forming hydrogels in situ.  Overall, by applying chemistry-driven approaches to engineer defined structures in the precursor components of hydrogels, gels with well-defined and tunable properties that are directly related to the structure of those precursor polymers can be achieved, permitting the preparation of injectable hydrogels with highly analogous chemistries but different bulk properties.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Late Cretaceous Sponge Borings - Indicators of Salinity and Sedimentation Drumheller, Alberta

contributor:
Risk, Michael J.
Geology

subject: cretaceous, sponge, borings, indicators, salinity, sedimentation, morphotypes

abstract:
 A detailed study of sponge boring morphotypes within the molluscan fauna of Upper Cretaceous estuarine sediments near Drumheller, Alberta provides information relevant to the
depositional environment. Problems with regard to utilizing Entobia as a paleoenvironmental indicator and as an indicator of salinity do not appear to be insurmountable.

 Distributions and characteristics of associated marine organisms (phoronid worms, gastropods and encrusting bryozoa) suggest that sponge colonies were affected by salinity and
sedimentation. Boring networks in Ostrea glabra suggest that more than one species of sponge were present. Sponge distribution patterns, changes in papilla and chamber sizes and preferential occurrence of sponge borings on certain shell thicknesses provide good evidence for responses to salinity and sedimentation.

abstract: Thesis

abstract: Bachelor of Science (BSc)


title: Brittle-Ductile Shear Zones Northwest of the Grenville Front Mylonite Zone, Killarney, Ontario

contributor:
Clifford, P. M.
Geography and Geology

subject: brittle-ductile, shear, zones, northwest, mylonite, deformation, rock

abstract:
 Small shear zones located northwest of the Grenville Front Mylonite Zone exhibit both a brittle and ductile deformation history. Textures reveal that an earlier mylonitic rock has been overprinted by one which demonstrates textures typical of brittle cataclasis.

 ductile deformation has occurred under greenschist facies conditions, while a later, brittle event has occurred below lower greenschist temperatures. These produce high shear strain values which lie between 14.44 and 10.79.

 Upper and lower age limits for the initiation of shear
zones have been determined as being prior to the emplacement of pegmatite dykes, and up until the formation of brittle-ductile shear zones found locally. Thus, they have developed
between 1400 ± 50 Ma and approximately 1100 + ? Ma.

abstract: Thesis

abstract: Bachelor of Arts (BA)


title: Synthesis and Characterization of Well-Defined Dimethylaminoethyl Methacrylate Polyelectrolytes for Non-Viral Antisense Oligonucleotides Deliveries

contributor:
Zhu, Shiping
Chemical Engineering

subject: synthesis, characterization, polyelectrolytes, deliveries, antisense, non-viral, oligonucleotides, cationic, molecular weight

abstract:
 Cationic polyelectrolytes have attracted growing attention in the field of non-viral
oligonucleotides (ONs) deliveries because of their ability to bind ONs by electrostatic
interactions for efficient cellular uptake. However the formation of electrostatic
polymer/ONs complexes and their biological effects are still poorly understood. The
relationships between polymer structure and complexation performance have not been
well established. The objectives of this research are to synthesize and characterize well-defined and well-controlled cationic polyelectrolytes and to evaluate the effects of
polyelectrolyte chain properties on ONs complexation. Poly(2-(dimethylamino) ethyl
methacrylate) (polyDMAEMA) and its derivatives are used as the polymer candidate. A
fluorescein-labeled oligonucleotide, 5 '-FGCGGAGCGTGGCAGG-3' (F: fluorescein), is
used as the oligonucleotide candidate.

 Low-molecular-weight cationic polyDMAEMA samples having narrow molecular weight distribution were synthesized by living anionic polymerization (LAP) and atom transfer radical polymerization (ATRP) methods. Fully charged polyDMAEMA quats were prepared by sequential quaternization of polyDMAEMA samples, as well as by direct ATRP of the quaternized DMAEMA monomer. An aqueous GPC calibration
method was first developed for the characterization of these cationic polyelectrolytes. It
was found that the type of counter-ion has little effect on the hydrodynamic volume of
polyDMAEMA quat. Therefore the dimethyl sulfate salt of polyDMAEMA provided a
reliable calibration standard for other types of quaternized DMAEMA homopolymers.

 Cationic block copolymers of polyDMAEMA with 2-hydroxyethyl methacrylate
(HEMA) and polyethylene glycol (PEG) were also prepared by ATRP. It was found that
the order of monomer addition, solvent type, temperature, and molecular weight of
macroinitiator have significant effects on the living feature of the polymerization. Well-controlled block copolymers were obtained when polyHEMA was used as the macro initiator.

 The complexation capability of the prepared polyelectrolytes with
oligonucleotides (15 mer) was evaluated by a fluorescence technique. It was found that
the complexation performance depends on polymer molecular weight, charge density,
and counter-ion type, as well as polymer concentration and block composition. The
polymer sample that has double molecular weight of the ONs gave the optimal
complexation performance.

abstract: Thesis

abstract: Master of Applied Science (MASc)


contributor:
Saravanamuttu, Kalaichelvi
Engineering Physics

abstract: Title: Laser Induced Self-Action Phenomena in a Photopolymerisable Medium, Author: Ana B. Villafranca, Location: Mills

abstract:
The nonlinear propagation of a visible, continuous wave laser beam in a photopolymerizable organosiloxane was studied at intensities ranging across 10 orders of magnitude (3.2x10-5 to 12732 W /cm2). The process was characterised in detail through spatial intensity profiles of the beam, temporal monitoring of its width and peak intensity combined with optical microscopy of the resulting self-induced structures.

These observations revealed a rich diversity of dynamic phenomena during nonlinear light propagation in different intensity regimes including (i) optical self-trapping (ii) in situ sequential excitation of high-order modes (corresponding to optical fiber modes) in self-written cylindrical waveguides, (iii) variations in modal composition during the transition of self-written waveguides from single to multimode guidance, (iv) generation of spatial diffraction rings that propagated over long distances (>Rayleigh length), (v) transformation of the Gaussian beam into an unstable single ring, which collapsed into azimuthally symmetric filaments and (vi) complete beam filamentation.

Extensive and quantitative analyses of spatial beam profiles provided insight into
the mechanisms underlying each of these phenomena, particularly the significance of the spatial profile (gradient) of refractive index changes induced in the medium. The experimental findings were consistent with results of numerical simulations of nonlinear light propagation in the corresponding intensity range that were implemented through the beam propagation method with the software BeamPROP™. The results
of these comprehensive series of experimental and theoretical studies provide a deep understanding of the dynamics of nonlinear light propagation in a photopolymerizable medium and are consistent with some predictions of earlier theoretical models.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Utilizing silver and copper ions for bacterial disinfection and subsequent removal of ions to supply safe drinking water

contributor:
Kim, Younggy
Civil Engineering

subject: Water Copper Silver Disinfection

abstract: Inadequate access to safe drinking water is a critical challenge facing millions of people in third world countries. Ionic silver and copper both have proven biocidal capacities and are used in various water treatment applications such as cooling water and swimming pool disinfection. However, these methods of bacterial inactivation have not been expanded to include drinking water treatment due to the inherent health risks associated with consuming high concentrations of the metals which can accumulate in the systems, and therefore also the treated water. The goal of this research was to utilize copper and silver ions to inactivate bacteria in order to provide a method of drinking water treatment that does not require the use of toxic chemicals or large amounts of electricity, as under resourced communities do not have reliable access to these resources. This research also examined methods of removing or recovering residual metal from treated water. The ability to reduce the residual metal concentration not only allows the effluent to meet drinking water guidelines, it also allows for the concentration of metal used during disinfection to be significantly larger than used in previous research. By using a metal concentration that is one or two orders of magnitude higher than typical silver or copper ionization the disinfection is able to be carried out faster and to a fuller extent, all the while not increasing the risk to the consumer as the metal concentration can be decreased to within an acceptable range post disinfection. The lab scale, proof of concept methods used in this research show strong potential as prospective techniques to provide safe drinking water to people in third world nations.

abstract: Thesis

abstract: Master of Applied Science (MASc)