title: Peptide Hydrolases in Maize Endosperm

contributor:
Oaks, Ann B.
Biology

subject: Biology Biology

abstract:
'The enzymes responsible for hydrolysis of reserve protein in endosperm tissue during early growth of maize seedlings were investigated. The ma~n areas of research included:

(1) studies to optimize endopeptidase, carboxypeptidase and aminopeptidase reactions.

(2) a partial purification of the' endopeptidase protein.

(3) an investigation of the e~fects of certain plant hormones on the formation of the peptide hydrolase activities in en90sperm tissue of maize (W64 x W182E).

Assays which could measure endopeptidase, carboxypeptidase and aminopeptidase activities were studied in extracts of endosperm tissue prepared from Zea mays. As a substrate for the endopeptidase assay haemoglobin was more reactive than gliadin, BSA, azocoll or azocasein. Synthetic substrates were used to assay carboxypeptidase activity, due to Ala) and aminopeptidase (Leu-para-nitroaniline). Interference with measurement of carboxypeptidase activity, due to autolysis, could be eliminated by dialysis of the extract. The dependence of the activities upon pH, concentration of substrate, volume of extract and temperature were investigated. Optimum conditions were established. Routinely, saturating protein concentrations were used in the acidic endopeptidase assays whereas the peptidase assays were performed at less than saturating substrate concentrations due to limited solubility of the substrates.

The effects of selected enzyme inhibitors on the enzyme activities were tested. Para-chloromercuribenzoate gave the greatest inhibition of all activities. Aminopeptidase was most sensitive, followed by carboxypeptidase and then acid endopeptidase. Other inhib~tors (PMSF and EDTA) had slight effects. Aminopeptidase was sensitive to 5 mM phenylmethylsulphonylfluoride whereas the carboxy-peptidase and endopeptidase were not significantly affected.

A number of techniques were used in an attempt to purify the acid endopeptidase. Acid endopeptidase activity was clearly separated from carboxypeptidase activity on Sephadex G-50. The best partial purification of an endopeptidase fraction was achieved with Sephadex G-50 chromatography, followed by CM-cellulose chromatography. A thirteen fold increase in specific activity was attained. The molecular weight of the most pure fraction was estimated to be 21,000 daltons, using a Sephadex G-200 column.

The development of acid endopeptidase, carboxypeptidase and aminopeptidase was followed in the post pollination and post germination periods. The exopeptidase activities were high in the post pollination tissues, while acid endopeptidase was low. The latter activity rose after imbibition, reaching a peak at five to eight days. Carboxy-peptidase also increased in activity following imbibition, while aminopeptidase activity declined from the value found in the mature caryopsis.

Endosperms, from which the embryo and scutellum had been removed were incubated in the presence of plant hormones and chemical effectors. Unlike barley (Hordeum vulgare), in which GA₃ is required to induce development of a protease activity in halfseeds, GA₃ is not required for development of endopeptidase activity in deembryonated caryopses of maize (Zea mays). In the present study, it was found that GA₃ did not affect the appearance of exopeptidase activities either. Incubation with 2 μM abscisic acid (ABA) caused partial inhibition of the development of endopeptidase and carboxypeptidase activities. At a concentration of 10 μM, significant inhibition of aminopeptidase develppment was also seen. GA₃ (30 μM) could partially reverse the inhibition of acid endopeptidase and carboxypeptidase caused by the lower concentration of ABA. Cordycepin, an inhibitor of RNA formation, was found to have no effect on either the development of protease activity, or the inhibition brought about the ABA, although it did inhibit development of α-amylase in barley and maize endosperm pieces. Cycloheximide, a protein synthesis inhibitor drastically decreased the production of all peptide hydrolase activities.

abstract: Master of Science (MS)


title: AVERAGE RESONANCE CAPTURE IN COBALT AND MANGANESE USING BORON-10 FILTER TECHNIQUE

contributor:
Prestwich, W.V.
Nuclear Physics

subject: Nuclear Nuclear

abstract: The high energy gamma rays from the radiative capture of B¹⁰ filtered neutrons in Mn⁵⁵ and Co⁵⁹ were measured and analyzed in terms of statistical and direct capture model of nuclear reactions. A high resolution NaI(T1)-Ge(Li) pair spectrometer was used to detect the gamma rays. Correlations between (n,Υ) and (d,p) intensities were determined for these nuclei. The distributions of the reduced intensities were also studied and compared with the predictions of the statistical model. Finally an attempt was made to determine a direct capture component in the Co⁶⁰ ground state partial cross-section. It was found that the ground state data could be explained with the resonance amplitudes alone. The following amplitudes were deduced: [equation removed]

abstract: Doctor of Philosophy (PhD)


title: SECTORAL FINANCIAL STRUCTURE AND FINANCIAL PLANNING IN EGYPT

contributor:
Kuburai, A.A.
Finance

subject:
Finance and Financial Management
Finance and Financial Management

abstract: This thesis has two major objectives. The first objective is to analyze the aggregate financial assets and financial flows, and as well their sectoral composition, in the Egyptian economy over the period 1952 through 1970. To pursue this study a Gross Financial Stocks Interrelation Matrix, the stock equivalent of the extended version of the lending/borrowing matrix was formulated for Egypt at eight points in time between 1952 and 1970. Our motivation for undertaking this study is based on the lack of literature analysing the financial flows of the non-financial sectors in Egypt. The literature on the financial structure of the Egyptian economy was limited to the institutions and assets of the financial sector. An interesting finding of this study is that the assumption of control over the economy by the Egyptian government in 1961 did not have much impact on the structure and the size of the financial flows. The second objective of the thesis is to prevent a technique of financial planning which is designed to aid in contolling the amount of high powered money issues by the central bank and thus the money supply prevailing in Egypt. in this respect, it was found that reasonable degree of accuracy in forecasting sectoral financial assets can be achieved by using naive forecast models. This means that, even in the absence of sophisticated econometric models of the Egyptian economy, a reasonable degree of accuracy in planning monetary aggregates can still be achieved.

abstract: Doctor of Philosophy (PhD)


title: An Investigation of Some New Tree Structures

contributor:
Wood, D.
Library Science

subject:
Library and Information Science
Library and Information Science

abstract:
A study of the tree structures developed by Finkel and Bentley (3 & 4) was done and the results are documented in this report. These tree structures, i.e. the quad tree and the k-d tree, were especially developed for associative retrieval. A comparison of the above tree structures and the well known binary search tree is presented for exact match queries.

An implementation of the insertion algorithms for each tree structure and a generalization of Aldon Walker's (9) display algorithm are given.

abstract: Doctor of Philosophy (PhD)


title: Thermoelectric Power of Hg₂․₈₆AsF₆

contributor:
Datars, W.R.
Physics

subject: Physics Physics

abstract: An apparatus was developed to measure the Seebeck e.m.f. of small specimens which have to be handled in a dry-box and to which only mechanical contact can be made. The method is successful if the electrical conductivity of the contacts is much larger than that of the sample. Utilizing this apparatus, the temperature dependence of the thermopower of Hg₂․₈₆AsF₆ was investigated along its two principal directions. Metallic conduction was found which is electron dominated in the a,b directions and hole dominated in the c direction. Therefore, the temperature dependence observed in the thermopower is explained using the free electron model, in which the total thermopower is expressed as the sum of a diffusion component, dominating above 100 K, and a phonon drag component dominating below 100 K. Thus, the Fermi energy is calculated to be 4.6±0.5 eV and the Debye temperature is fixed between 60 K and 90 K.

abstract: Master of Science (MS)


title: The cleaning of InP substrates for growth by MBE

contributor:
Thompson, D.A.
Condensation

subject:
Physical Sciences and Mathematics
Physical Sciences and Mathematics

abstract:
A novel technique of using an in-situ ECR generated H-plasma to produce high quality surfaces on InP substrates, for growth of n- and p-type InP layers by GSMBE, has been investigated. The initial substrate surface quality determines the quality of the subsequently grown layers and therefore, the cleaning procedure is of critical importance. The standard approach entails a thermal desorption of a passivating oxide; however, this technique leaves carbon on the surface and, because oxides may vary in composition depending on the growth conditions, a consistent temperature for desorption may not be obtained. The desorption process is also dependent on the atmosphere in which it is carried out; i.e. whether an overpressure of P₂ or As₂ is used. Thermal desorption of oxides from InP requires the substrate to reach temperatures higher than normal GSMBE growth temperatures which can lead to substrate decomposition and, for regrowth applications, can alter dopant profiles and layer composition in ternary and quaternary layer growths. As an alternative, H-plasmas in separate vacuum chambers have been used to remove oxides from InP but this typically produces highly defective substrates due to a loss of phosphorus from the substrate. In this work the combination of an in-situ H-plasma with a stabilizing atmosphere of P₂ is used for the removal of oxides at temperatures equal to growth temperature and below.

The mechanism involved in the thermal desorption of an oxide is first clarified and this procedure is compared with oxide removal by H-plasma etch in a phosphorus atmosphere. The ECR source can produce various plasma modes which have been thoroughly characterized. The effect of the different plasma conditions on clean lnP is determined. These modes have different properties which result in different oxide etch rates. Various modes are compared and the mechanism of oxide removal is documented. As an alternative to oxide growth S-passivation has recently received attention as a surface passivation technique. Application of this surface, with and without H-plasma cleaning, has been investigated. The above treatments and other wet chemical surface treatments are compared to determine the optimal surface cleaning technique.

The results indicate that thermal desorptions are driven by reaction with phosphorus from the substrate and therefore require high temperatures to promote significant phosphorus evaporation from the substrate. A H-plasma etch of the oxide is driven by the presence of atomic H in the plasma and results in the formation of water. Oxide removal rates were determined at various temperatures from 250°C - 490°C. The plasma etch was found to remove carbon contamination from the surface whereas, thermal desorptions do not. Defect levels in the underlying lnP are sensitive to the plasma properties but with careful choice of plasma conditions defect states can be minimized. An optimal surface cleaning procedure has been developed which involves a UV-ozone treatment and H-plasma cleaning, resulting in interfaces free of electrically active defects in n-type material and a defect concentration of 8x10¹¹ cm⁻² in p-type material.

abstract: Doctor of Philosophy (PhD)


title: The Colloidal Stability and Surface Chemistry of Stöber Silica

contributor:
Brook, Michael A.
Pelton, Robert

abstract:
Colloidal silica was prepared by the Stöber method to give particles having a narrow size distribution and spherical geometry. The electrokinetic and coagulation behavior of the particles were investigated in water, acetone, and acetone-water mixtures and the experimental data were compared to simple theoretical models. The relative permittivity, er. of the dispersion medium was varied between 21 and 79 by controlling the acetone:water ratio. For εᵣ >33, the particles could not be coagulated using Nal concentrations up to 0.5 M. The critical coagulation concentration (Cᴄ) values could not be predicted by calculations based on using standard DLVO theory. In the absence of salt, the zeta-potentials (ζ-potentials) remained constant at approximately -50 mV when 24.3 < εᵣ < 78.5 but increased to -80 mV for εᵣ < 24.3. A single-site dissociation model predicted that the ζ-potentials should decrease with increasing acetone content. The inability of the theoretical models to predict the colloidal stability behavior of silica in acetone and acetone - water mixtures, especially when εᵣ > 33, was believed to be due to the presence of a silica ger surface layer which acted as a stene barrier at short-range interparticle distances.

The colloidal stability and surface properties of Stöber silica modified with triethoxysilane (TES) (HSi(OEt)₃) was studied (polyTES). The polyTES particles were reacted with vinylnaphthalene, styrene, and vinyl-terminated poly(dimethylsiloxanes) using the platinum-catalyzed hydrosilation reaction. These reactions demonstrated that Stöber silica modified with TES can lead to a variety of colloidally stable dispersions in solvents ranging in polarity from water to hexane. It was also shown that bis(1,3-divinyl,1,1,3,3-tetramethyldisiloxane)Pt⁰ could be hydrosilated on the polyTES surface to give catalytically active, surface-bound platinum nanoparticles with an average diameter of 2 nm. The polyTES layer grafted to the silica surface was believed to be critical in controlling the ultimate size of the supported platinum nanoparticles. The surface properties of the polyTES particles were studied and it was shown that the polyTES chains had a high surface density of 2.22 nm⁻² and they expanded when solvated by aqueous alkaline solutions.

abstract: Doctor of Philosophy (PhD)


title: John Berger's Fictional Acts of Faith

contributor:
Petrie, G.
English

subject:
English Language and Literature
English Language and Literature

abstract:
John Berger is well known to a certain segment of the general public, especially in England and Europe, for his critical art essays and reviews, and is thought of as a populist of aesthetics.

This thesis constitutes the first comprehensive examination of Berger's fiction. It treats Berger as a thinker and a writer-- not simply as a populist of aesthetics-- and therefore broadens the context in which he is usually considered. Chapter One provides an overview of Berger's methodology and aesthetlc. Chapter Two examines his first three novels in terms of his empathetic response to the class of people with which these novels are concerned, the nature of the dream as manifest in these novels, and Berger's concept of the heroic. Chapter Three is a close reading of G. and the theories of time it sets forth. Chapter Four considers the views of memory and experience in Berger's last two works of fiction, and the reasons for his turning to traditional narrative form. The work as a whole traces Berger's struggle to get "close to the face of experience".

By examining each of Berger's works of fiction to determine both how each is informed by his critical perspective and ideology and how each manifests a stage in his evolution as a writer and thinker, this thesis makes the claim that Berger deserves as much recognition for his creative writing as he has received for his (distinctly creative) criticism. This work maintains that though his fiction moves increasingly in the direction of philosophical speculation, it loses none of its political impact.

abstract: Doctor of Philosophy (PhD)


title: Diagenesis and transformation of aquatic dissolved organic matter in Nova Scotia freshwaters

contributor:
Kramer, J.R.
Hydrology

subject:
Environmental Sciences
Environmental Sciences

abstract: The acid-base and structural chemistry of freshwater dissolved organic matter (DOM) is known to vary with time and location. The purpose of this dissertation is to show how the chemical quality of DOM in temperate streams, wetlands and lakes of the Kejimkujik National Park area in central Nova Scotia varies over an annual cycle and how the changes in quality are related to DOM formation and diagenesis. New techniques were developed and used to better define the chemical quality DOM. A titration method described by Brassard et al. (1990) allowed the description of the acid-base characteristics of DOM. A reverse osmosis method is also described for the concentration of DOM without its fractionation to allow structural determination by ¹³C NMR of whole material. The results indicate that the chemical quality of DOM found in freshwaters is not similar to that found in soils. This difference suggests that interactions between soils, biology and hydrology modify the DOM in streams. A laboratory experiment suggests that the most likely pathway of DOM formation is the breakdown of plant structural material into aliphatic material with subsequent aromatic formation via semi-quinone and quinone. Comparison of incubation experiments with field results also shows that DOM acidity in natural water decreases with time caused by biological and chemical oxidative processes. Theoretical considerations indicate that the acidity of DOM does not follow the simple relationship suggested by Oliver et al. (1983) because of differences in source material and diagenetic processes, as well as the influence of inorganic cations and anions which until now have been assumed to be uncomplexed with organic matter.

abstract: Doctor of Philosophy (PhD)


title: The use of thrombin inhibitors to examine the role of thrombin as a mediator of (a) reocclusion after successful thrombolysis, and (b) smooth muscle hyperplasia after vessel wall injury in animal model systems

contributor:
Hirsh, J.
Anatomy

subject: Anatomy Physiology Anatomy

abstract:
Using antithrombin III-dependent and independent thrombin inhibitors, we evaluated the role of thrombin in (a) reocclusion after successful thrombolysis, and (b) intimal thickening and stenosis induced by injury to a vessel wall. To accomplish this, two animal models were developed in the rat. The first was a model of tissue plasminogen activator (tPA) induced-thrombolysis, whereas the second was a carotid model of injury-induced stenosis.

In the rat model of tPA-induced thrombolysis, we compared the effects of heparin, hirudin, hirulog (a synthetic hirudin-derived peptide), and D-Phe-Pro-ArgCH₂Cl (PPACK) in doses that produced a 4-fold prolongation of the baseline activated partial thromboplastin time (APTT) with saline, in terms of their ability to accelerate thrombolysis and to prevent reocclusion. A thrombus rich in red cells and fibrin was formed in the distal aorta by a combination of vessel injury and stasis. Thrombolysis was induced with tPA (1 mg/kg bolus, followed by 1 mg/kg/hr over 30 min.) and the rats were randomized to receive a concomitant 80 min. infusion of a thrombin inhibitor or saline. Blood flow and pre- and post-stenotic blood pressures were monitored continuously, and the time to clot lysis, the duration of vessel patency, and the number of reocclusions were determined. Compared to saline, heparin had no significant effect on these variables. In contrast, hirudin, hirulog and PPACK significantly (p<0.01) increased the percentage of time that the vessel remained patent from 63.9 ± 7.7 to 90.7 ± 2.2, 94.0 ± 0.9, and 94.7 ± 1.0% respectively, by significantly (p<0.01) decreasing the number of reocclusions. The superiority of the ATIII-independent inhibitors over heparin supports the hypothesis that the limited effectiveness of heparin in this setting reflects its inability to inactivate clot-bound thrombin. Compared to saline, hirulog and PPACK also significantly (p<0.02) accelerated the time to thrombolysis from 10.5 ± 2.3 to 4.4 ± 0.6, and 4.2 ± 0.8 min., respectively, whereas heparin and hirudin did not. The ability of the lower molecular weight inhibitors of thrombin to accelerate lysis may reflect their greater accessibility to clot-bound thrombin. Hirudin, standard heparin, and low molecular weight heparin were compared with saline in terms of their ability to prevent injury-induced stenosis in the rat common carotid artery. After balloon injury, animals were randomized to receive a one week course of subcutaneous treatment with a thrombin inhibitor or saline. All of the thrombin inhibitors were given in concentrations that produced a continuous 6-fold prolongation of the baseline thrombin clotting times, and 2-fold prolongation of the APTT. Two weeks after injury, the animals were euthanized and the extent of stenosis was assessed by a combination of quantitative angiography, resin casting, and planimetry. Compared to saline, only low molecular weight heparin significantly (p<0.01) inhibited injury-induced stenosis as assessed by angiography (from 22.9 ± 3.0% to 8.8 ± 7.8%), resin casting (from 46.7 ± 4.8% to 22.5 ± 8.3%), and by planimetry (from 21.8 ± 3.4% to 11.3 ± 2.1%). (Abstract shortened by UMI.)

abstract: Doctor of Philosophy (PhD)


title: Nabokov and Ada

contributor:
Brückmann, P.
English

abstract:
Ada has tended to hinder the study of Nobokov's works both by its exceptional difficultyand by its appearing to confirm suspicions of Nabokov's artistic and moral self-indulgence. By elucidating Ada this thesis seeks not only to surmount the obstacle of the novel's difficulty but also to demonstrate the book's artistic control, phiiosophic range and moral force, and at the same time to chart Nabokov's reeurrent literary tactics and to analyze the nature of his phlosophy and his moral concerns.

Since to appreciate Ada it is necessary to understand the full depth of Nabokov' s originality of artistic strategy and the challenge of his philosophical inquiry--and simply because neither of these has been understood before--the thesis commences by considering the nature of Nabokov's style (Chapter 1, which concentrates on Ada) and his thought (Chapter 2, which draws on all his works) before examining each of the Parts of Ada in turn (Chapters 3-9). Ada is seen partly in terms of the differences between a first reading, rereadings, and a "final" reading of the novel but chiefly in terms of the mlnute correlations of phrase or incident--of a delicacy and complexity unequaled in fiction--which intensify the comedy and adventure of rereadings and establish the seriousness and the surprise of a final reading.

The first two chapters of the thesis examine how Nabokov's curiosity about the position of consciousness in the unlverse shapes his strategies and style and directs his investigations of the nature of space, time and human consciousness and of the possibilities of forms of consciousness beyond the human. The analysis of Ada, will reveal--quietly at first but with increasltig resonance--the consistency of Nabokov's ideas of consciousness and yet the variety of concerns these ideas touch upon: the infinity of sensation and emotion and thought within the finitude of human existence; the mysterious possibility of a transmutation of mortal consciousness into some state of timelessness; the even more mysterious possibility of conscious design in the universe; the demand of moral responsibility that are inevitably bound up with the privilege of consciousness.

abstract: Doctor of Philosophy (PhD)


title: Collocation models for distillation units and sensitivity analysis studies in process optimization

contributor:
Hrymak, A. N.
Chemical Engineering

subject:
Chemical Engineering
Chemical Engineering

abstract:
This thesis examines problems in two related subject areas.

The first subject area involves the development orthogonal collocation on finite elements (OCFE) models for stagewise distillation processes for use in steady-state optimization. The OCFE model formulation divides the column sections into smaller subdomains (finite elements) in order to track irregularities in the column profiles. Stages that have feed or sidestreams entering or leaving the column are modeled as discrete equilibrium stages in the OCFE model. An adaptive element breakpoint placement procedure determines an element partition for each column section so that a solution of improved accuracy is obtained. The element partition is based on the equidistribution of the material and energy balances residuals around envelopes in the column. OCFE models converge to the same optimal solution as tray-by-tray models in less computational time, but have similar sensitivity at the optimum with respect to major model parameters.

The second area involves the study of parametric sensitivity analysis in process optimization. A sensitivity analysis procedure is developed that calculates the behaviour of the optimal solution for changes in one independent parameter using continuation methods. A procedure is proposed to modify the equation set which allows the study of the effects of multiple simultaneous parameter variations along specified directions in the optimal solution. Special attention is given to the detection and analysis of singularities in the optimal solution path caused by violation of either the strict complementarity, linear independence or second-order optimality conditions. The methodology provides information to determine the range of parameter estimate variation for which the active constraint set or the characteristics of the optimal solution remain unchanged. The adjustment of the independent variables in a multiple unit flowsheet, so that optimality is maintail'ed, is investigated in the presence of model parameter variation.

abstract: Doctor of Philosophy (PhD)


title: EVASION OF THE HUMAN CELLULAR IMMUNE RESPONSE BY HERPES SIMPLEX VIRUS

contributor: Medical Sciences (Molecular Virology and Immunology Program)

subject:
Medical Sciences
Medical Sciences

abstract:
Herpes simplex virus (HSV) is unusual in its ability to cause recurrent infection in a host with an ostensibly competent immune system. This thesis describes two mechanisms by which HSV evades the cellular immune response, which contribute to its ability to persist.

Human cells infected with HSV inhibit lysis by natural killer (NK) and lymphokine-activated killer (LAK) cells. Contrary to the conclusions of previous workers, this effect is due to infection of the lytic effector cells, as shown by experiments with mutant HSV and by immunofluorescence staining of effector cells in contact with HSV-infected targets. The inhibition of lytic effector cells by HSV by cell-to-cell spread may play an important role late in the infectious cycle.

Early in the infectious cycle, infectious virus is not present and the above mechanism cannot take effect. Instead, HSV imposes a block on the cellular pathway which presents antigen to CD8⁺ cytotoxic T lymphocytes. The result is that HSV-infected human fibroblasts show abnormalities of their class I major histocompatibility complex (MHC class I) similar to those seen in antigenpresenting mutant cell lines: the MHC class I is retained within the ER and is misfolded and unstable, implying that peptide is not associated with the heavy chain/β₂-microglobulin complex. Experiments with mutant and recombinant viruses established that this effect is due to an HSV irnmediate-early protein, ICP47, and showed that cells expressing ICP47 are not efficiently recognized and lysed by CD8+ CTL. Since ICP47 is not detectably membrane-associated, it presumably affects some cytoplasmic component of the antigen-processing pathway. One candidate for this cellular target is a small (8.5 - 9 kDa) protein, which, like ICP47, is located within the cytoplasm and nucleus of certain cell types. This protein was detected by its ability to bind to a protein consisting of ICP47 fused to the carboxy terminus of glutathione S-transferase (GST).

abstract: Doctor of Philosophy (PhD)


title: Biophysical studies of pulsed photothermal radiometry in tissues and tissue-like media

contributor:
Wilson, B.
Anatomy

subject: Anatomy Physiology Anatomy

abstract: Pulsed Photothermal Radiometry (PPTR) is a remote sensing technique which monitors the temperature transient at the surface of a sample following the absorption of a brief optical pulse. In this work, it was used to investigate optical and thermal processes occurring in laser-irradiated, turbid, inhomogeneous media such as tissue. An optical diffusion approximation and heat conduction equation were used to derive the turbid PPTR model, for both homogeneous and layered semi-infinite media. These models were tested experimentally in a series of aqueous gel phantoms of known optical and thermal properties, and were found to be in good agreement. A study of discrete optical absorbers in a transparent medium necessitated the inclusion of the thermal radiative effects as an additional mode of heat transfer, and a corresponding PPTR model was derived and tested experimentally. Studies of intact biomolecules and of in-vivo tissue have also been performed to test and verify the derived formulations, and to determine the practical utility of PPTR for specific biomedical applications. The theoretical and experimental results presented in the thesis lay the groundwork for further inclusion of PPTR into the diagnostic arsenal of laser medicine.

abstract: Doctor of Philosophy (PhD)


title: Emotion and object

subject: Philosophy Philosophy

abstract: Doctor of Philosophy (PhD)


title: Physico-chemical Properties of Ribosomal RNA from Thermophilic Fungi

contributor:
Freeman, K.B.
Biochemistry

subject: Biochemistry Biochemistry

abstract:
Thermophilic fungi have the highest maximum growth temperature (60ºC) of any eukayotic organism. It might, therefore, be expected that its cellular components would have unusual physico-chemical properties resulting in increased thermostability. To investigate this, ribosomes and ribosomal DNA from Chaetomium thermophilic var. coprophile were compared to those of rat liver. Chaetomium cytosol ribosomes were observed to be more thermostable than rat liver ribosomes. However, the opposite relationship was found for their component ribosomal RNAs. These findings suggest that the thermostability of the Chaetomium ribosome results from unique RNA-protein interactions rather than from novel characteristics of its ribosomal RNAs.

An examination of Chaetomium mitochondrial ribosomal RNA revealed that in terms of sedimentation properties and electrophoretic mobilities, the two high molecular weight species resembled their cytosol counterparts. However, their G+C contents were intermediate between those of the cytosol RNA's and those of previously studied mitochondrial RNAs from mesophilic fungi. These observations represent the first demonstration in ascomycetes and animal, of mitochondrial ribosomal RNA with properties similar to those of its homologous cytosol immuniites.

abstract: Doctor of Philosophy (PhD)


title: Ethnicity and the Determinants of Cardiovascular Disease among South Asians, Chinese and European Canadians

contributor:
Yusuf, Salim
Health Research Methodology

subject:
Medicine and Health Sciences
Medicine and Health Sciences

abstract:
Significant differences in the cardiovascular mortality rate exist between Canadians of South Asian, Chinese and European origin. This thesis represents a six year effort to detennine the prevalence of cardiovascular disease, the burden of atherosclerosis, and the prevalence of their major determinants among three ethnic groups in Canada. In addition to the study of the relationship of the "classical" cardiovascular risk factors to disease outcomes, the contribution to disease outcomes of selected "emerging" risk factors (e.g. markers of thrombosis, socio-economic, dietary, and psychosocial stress factors) was studied.

The major findings reported in this thesis include the confirmation that South Asians in Canada have the greatest prevalence, Europeans have an intermediate prevalence, and the Chinese have the lowest prevalence of cardiovascular disease. However, Europeans have significantly more atherosclerosis compared to the South Asians and Chinese. Yet, for any given amount of atherosclerosis, South Asians suffer more cardiovascular events. This may reflect an increased propensity of South Asians to develop arterial thrombosis.

Major differences in the daily calorie consumption, and in the sources of calories exist between the ethnic groups. Diet was measured using food frequency questionnaires developed for each ethnic group, which were found to reliably classify individuals into high or low consumers for a given macronutrient. This classification facilitates the study of diet-disease relationships.

Psychosocial stress was measured in a valid and reliable way using a single questionnaire created for use by all participants. Discrimination in the workplace is a challenge to measure, and while it was reported more often among South Asians and Chinese, its reproducibility was relatively low. Markers of social stability (e.g. income and employment) were associated with psychosocial stress factors, neurohormones, atherosclerosis and cardiovascular disease. This demonstrates the powerful influence that "social factors" have on the health of free-living Canadians.

abstract: Doctor of Philosophy (PhD)


title: THE INWARD WORK: THE POLITICS OF DEVOTIONAL RHETORIC IN EARLY MODERN ENGLAND

subject:
Literature in English, British Isles
Literature in English, British Isles

abstract:
This dissertation examines the forms of cultural labour performed by devotional rhetoric in the writings of Robert Southwell, Richard Crashaw, John Donne, and Thomas Traherne. The general hypothesis here is that devotional forms of expression provided seventeenth-century individuals with much more than a means of expressing praise; they offered an imaginative space in which to articulate and mitigate the psychological effects of the de-animation of the sacramental cosmos. More specifically, the dissertation explores how these four writers record and seek to negotiate processes of de-sacramentalization (the separating of divine from mundane orders) by internalizing such processes, by registering them, that is, as an experience that occurs within the self. This staging of political and theological conflict as a division within the self provides devotional writers with a certain symbolic leverage. By situating external forms of conflict as inwardly experienced dramas, seventeenth-century devotional writers presume that the process of individual self-transformation or metanoia , which is the general aim of religious discipline in both Reformation and Counter-Reformation traditions, is also the means for achieving social harmony. In this thesis, I am primarily concerned with how devotional writers use particular rhetorical strategies in an effort to fashion an ideal religious subject, a subject that confronts social and cosmological disorder through acts of devotion and self-discipline. At bottom, then, this thesis examines how the rhetoric of subjection functions in early modern devotional contexts as a means of articulating and mitigating the psychological effects of social and theological crises.

In order to address the forms of cultural work at stake in Counter-Reformational and Anglican acts of praise, particularly the forms of self-transformation towards which devotional practices aim, I situate early modern texts alongside contemporary psychoanalysis. The primary goal of this juxtaposition is to illuminate the way that early modern devotional writers seek to transform readers in and through verbal acts of praise. Cognizant of the potential for anachronism in such an approach, I place devotional writers and psychoanalytic theory in dialogue with one another, rather than applying psychoanalysis to early modern works as such. In particular, I examine how both devotional discourses and psychoanalytic theory are concerned with understanding and transforming processes of subjection.

Through a series of historically and theoretically informed close readings, this thesis addresses the question of why devotion matters both culturally and psychologically. What is at stake in seventeenth-century Anglican and Catholic forms of devotional writing is nothing less than the most intimate dimensions of sacramental life. What is at stake, in other words, is how individuals articulate and experience themselves as images of God. By examining the way that devotional writers structure the experience of subjection to God, the way they give divine subjection concrete form through fantasy, we will better understand the psychic life of power at a moment in Reformation history when traditional forms of devotional and liturgical expression began to lose their authority.

abstract: Doctor of Philosophy (PhD)


title: AN ANALYSIS OF CARDIUM FORMATION EVENT STRATIGRAPHY

contributor:
Walker, R.G.
Geology

subject: Geology Geology

abstract:
Analysis of the sedimentary facies, early diagenesis and micropaleontology of event stratigraphy within the transgressive phase of the Cardium Formation indicates that changes of sea level occur during extremely short timespans possibly as short as 10,000 years. These rapid sea level changes produce either erosive or gradational boundaries between stratigraphic sequences. These boundaries termed Horizons.

Quantitative consideration of the foraminiferal population below, at and above these Horizons indicates that there was probably very little pause during the change in sea level; no unusual accumulations of biogenic debris occur. The foraminifera indicate that the waterbody was turbid and very likely diluted by fresh water. The resulting environmental stress persisted throughout Cardium time over a topographic 'bench' shorewards of the maximum extent of the regressive shoreline.

Fresh water dilution and possible increased organic supply encouraged the formation of synsedimentary siderite. Its ubiquitous occurence at the Horizons examined may indicate a short pause in sedimentation prior to renewed transgression, but the possibility of rapid sideritization makes this hypothesis unprovable.

Although subtle, some of the burrowing and cementation patterns characteristic of carbonate hardgrounds appear in the ubiquitously erosional fifth Horizon. The other Horizons are too gradational to show such behaviour.

All Horizons show rapid sedimentological changes. Erosion in one location may appear as a correlative conformity in another. Their behaviour indicates rapid changes in water depth.

As a whole the Cardium Formation probably represents a shoreline response to Late Turonian eustatic sea level change which was further influenced by shorter term tectonically induced sea level changes. With the exception of the fifth Horizon, the Horizons probably all formed subaqueously without a pause in sedimentation. Apart from changes from erosive to gradational contacts, Horizon behaviour is the same across the area studied.

abstract: Master of Science (MS)


title: SEDIMENTOLOGY OF THE CARDIUM FORMATION LOCHEND FIELD, ALBERTA

contributor:
Walker, R. G.
Geography and Geology

subject: Geology Geology

abstract:
Examination of 22 cores and over 100 petrophysical logs of the Turonian (Upper Cretaceous) Cardium Formation in the Lochend region permitted the identification of 9 facies which could be arranged into 3 major coarsening-upward cycles.At Lochend, the Burnstick Sequence comprises 5 distinct facies that progressively coarsen upward from a silt laminated mudstone through various bioturbated mud and sand facies into a gravelly conglomerate. There is a sharp return to a dark mud facies.

The overlying Raven River sequence in this region is characterized by a double coarsening upwards cycle which can be described in terms of 6 facies. The first cycle coarsens upward from a black laminated mudstone into various bioturbated mud and sand facies. The sands become progressively cleaner upwards before returning to a muddier bioturbated facies which marks the base of the second coarsening upward cycle. This cycle similarly decreases in mud content upwards but never 'cleans' to the extent of the lower cycle.

The upper-most "zone" sequence comprises muddy bioturbated facies which coarsen upwards into a 2 cm thick capping of conglomerate. There are no preserved physical sedimentary structures associated with any of the facies. The trace fossil assemblage indicates a sedimentary environment below fair weather wave but above storm wave base. The regional sandstone distribution of all coarsening upward sequences was investigated by cross section correlation of petrophysical logs between Lochend and Crossfield (to the west) and Caroline (to the north).

abstract: Bachelor of Science (BSc)


title: A Randomized Control Trial of The Effectiveness of OpSite Wound Versus lV. 3000 In Maintaining An Occlusive Central Line Dressing

contributor:
Roberts, Jacqueline
Health Sciences

subject: Equipment and Supplies

subject: Other Analytical, Diagnostic and Therapeutic Techniques and Equipment

subject: Perioperative, Operating Room and Surgical Nursing

subject: Equipment and Supplies

abstract: The use of both percutaneous and tunnelled central venous catheters in hospitalized patients has increased markedly over the last decade (Camp-Sorrell, 1990). With this increase, there is a clinical need to have an occlusive central line dressing to maintain a barrier to possible site contamination. This randomized control trial examined the use of the transparent dressing OpSite Wound (Smith and Nephew-Ine.) versus the ransparent dressing LV. 3000 (Smith & Nephew Inc.) in its ability to maintain an occlusive central line dressing. The study took place at Chedoke-McMaster Hospitals McMaster Division from June 1991 to September 1991. Adult medical-surgical patients who had a central line in place for longer than 48 hours were eligible for the study. Twenty five central lines were randomized to either the control group (OpSite Wound) or the experimental group (LV. 3000) An independent assessor saw all study patients daily to document dressing adhesiveness and the number of dressing changes performed. Analysis showed that the LV. 3000 dressing was changed every 5.5 days as opposed to the OpSite Wound dressing that was changed every 2.6 days. This difference was both statistically and clinically significant Analysis also showed that the dressings covering central lines with no intravenous in-line attachment (pigtail) were changed more frequently than the dressings covering central lines with an attached pigtail. This difference was also statistically significant The LV. 3000 dressing therefore, provides an occlusive central line dressing that is changed one-half the number of times that the OpSite Wound dressing is changed, or in other words, the OpSite. Wound dressing is changed twice as often as the I.V. 3000 dressing when used on central lines.

abstract: Master of Health Sciences (MSc)


title: Geometry of Facies Packages and E5 Erosian Surface in the Cardium Formation, Ferrier Field

contributor:
Walker, R. G.
Geology

subject: Geology Geology

abstract: The Upper Cretaceous (Turonian) Cardium Formation was deposited along the western margin of the Western Interior Seaway, within the Alberta Foreland Basin of the Canadian Cordillera. Like other Cretaceous formations within the Western Interior Seaway, it is characterized by a series of linear sandstone and conglomerate bodies encased in marine shales. Ferrier oil field is one of the western-most of the Cardium linear sand ridges. The Raven River Member in Ferrier field consists of two coarsening-upward sequences. The upper sequence contains hummocky cross-stratified sandstones, which suggest deposition below fairweather wave base. Cross sections show that the two sequences are scoured to variable depths by a major erosion surface (termed "E5"). The E5 erosion surface defines an undulating topography of gently and steeply dipping surfaces, termed "terraces" and "bevels",u respectively. Ferrier field and neighbouring Willesden Green field are terraces; an erosional bevel coincident with the northeastern margin of Ferrier separates the two terraces. These morphological elements cannot be explained by either totally subaqueous or totally subaerial erosion; erosion at the shoreface during stillstands of sea level is invoked. The terraces at Ferrier and Willesden Green have gentle southwestward dips relative to horizontal well log markers, but were probably cut horizontally at fairweather wave base during stillstand. This suggests that the Raven River sediments were dipping to the northeast during shoreface incision. Since the mean dip of the terrace at Willesden Green (0.07 degrees) exceeds that of the terrace at Ferrier (0.03 degrees), a downward flexing of the sediment surface is suggested in addition to an initial basinward tilt. The conglomerates which immediately overlie the E5 erosion surface at northeastern Ferrier are interpreted to be shoreface gravels. Based on the morphology of the E5 erosion surface basin-wide, and assuming a constant depth to fairweather wave base of meters, it is possible to separate the horizontal vertical erosion components of stillstand and steady sea level rise from one another. In total, meters of vertical sea level rise occurred over the 85 kilometers which separates Carrot Creek field from western Ferrier field. Assuming that the rate of erosion effective during incision of the E5 surface to be 1.2m/year, then it would have taken just over 70,000 years to cut the erosion surface from Carrot Creek to Ferrier. During this time, sea level rose at an average rate of 1.9 mm/year.

abstract: Master of Science (MS)


title: LOCAL BUCKLING OF HIGH STRENGTH STEEL W-SHAPED SECTIONS

contributor:
Sivakumaran, K.S.
Civil Engineering

subject:
Civil Engineering
Civil Engineering

abstract: W-shaped steel members are widely used in various structural applications, such as buildings, bridges, and industrial complexes. The recent trend is to produce W -shaped sections using higher and higher strength steel as a replacement for mild-carbon steel, such as 300W steel. However, the width-to-thickness ratios (b/t or w/t) specified in the current CSA steel design standard (1995) for local buckling strength and ductility are based on studies using 300W steel. An investigation was carried out to study the local buckling behavior, with an emphasis placed on flange buckling of compression members, of W-shaped sections made of high strength steel. First, stress-strain characteristics of high strength steel of 350W, 480W and 700Q steel, along with the mild-carbon 300W steel, were determined using standard tensile tests. Based on these experimental material properties, analysis material models were derived for the finite element analysis. Analysis material models used in the finite element modeling were the multi-linear, modified tri-linear, and modified bi-linear models. The next part of the investigation included tests on stub columns of these selected steel grades having flanges at Class I limit based on the current design standard (CSA 1995). Based on the experimental results from these stub column lests, the applicability of b/t Class 1 limits for high strength steel sections were assessed. The experimental results showed that the reserve capacity (fu/fy) of all the stub columns were close to the sanle, regardless of the steel grade. However, the ductility of the W-shaped sections corresponding to each grade differed substantially. The 300W and 350W steel displayed much more ductility than the 480W and 700Q steel. It was concluded that the bIt limits of a Class I section, which was based on studies on the 300W steel, is also applicable to the 350W steel, but are not transferrable to the higher strength steels. The third part of this study used the analysis material models determined from the tensile tests into a finite element modeling, where a 9-node "assumed strain" shell element was employed. Due to the symmetric behavior of a stub column, a quarter of a stub column was used to simulate the W -shaped section subjected to uniform compression. Meanwhile, an idealized residual stress with parabolic distribution across the web and flange of the W-shaped section was assumed and incorporated in the finite element modeling. Comparing the finite element analysis results with the corresponding experimental results from the stub column tests, an appropriate material model was selected to be used for further finite element analysis. It was found that the results obtained from the tri-linear and multi-linear models were similar to each other, and the modified bi-linear material model best represented the experimental results. Using this bi-linear material model in the finite element analysis, strength and ductility of W-shaped sections with varying flange b/t ratios but constant w/t ratio were determined from the finite element analysis. Results showed that the 350W steel demonstrated characteristics similar to the 300W steel. However, the 700Q steel possessed very little ductility and reserve capacity. The 480W steel was excluded in this part of the study due to the uncertain results from its tensile test. In all of these steel grades, it was found that ductility and reserve capacity decreased as the bIt ratio increased. From both the experimental investigation and the finite element analysis, the b/t limits in the current design standards were found to be applicable to both 300W and 350W steel, but not to the 700Q steel.

abstract: Master of Engineering (ME)


title: Some Factors Affecting Maze Behaviour of Drosophila melanogaster

contributor:
H., S. F.
Biology

subject: Biology Biology

abstract: Previous experiments done by other workers indicated that associative learning in a complex maze could be demonstrated to exist for flies of some strains of Drosophila melanogaster. The experiments of this study gave similar results for the Canton S strain, however results indicative of learning, whether they are actually due to discrimination learning or pseudolearning, are only obtained for flies run through a maze with olfactory cues present in the past. The behaviour observed is shown to vary between the strains (Canton S and black) used.

abstract: Master of Science (MS)


title: X-RAY ABSORPTION FINE STRUCTURE SPECTROSCOPY OF THIN FILM SiGe ALLOYS

contributor:
Hitchcock, A.P.
Jackman, T. E.
Materials Engineering

subject:
Other Materials Science and Engineering
Other Materials Science and Engineering

abstract:
SiGe thin film alloys are the subject of intense interest in semiconductor research. The extent of bond length dependence upon alloy composition in these materials is a subject of some debate in the literature. This work details our Si and Ge K-edge extended x-ray absorption fine structure (EXAFS) measurements on a selection of strained and relaxed single crystal SiGe alloys. Constrained, simultaneous fits to the EXAFS of multiple spectra from both Si and Ge K-edges were performed in order to extract quantitative data for bond lengths and co-ordination numbers.

The first analysis was performed solely using EXAFS spectra from relaxed alloys grown on Si. The results indicate that first shell bonding in relaxed SiGe alloys adheres to a weakly mixed Pauling-Vegard regime, showing detectable composition dependence (bond length change of 0.03 A over the full composition range). In the

notation of the CT theory of Thorpe and co-workers (Phys. Rev. B 46,15872 (1992)), the topological rigidity parameter, a** is found to be 0.70+0.09 -0.03

The results are compared to other theoretical and experimental results, and alternate models to the CT theory are explored. Ordering effects in the co-ordination numbers are also evaluated.

The second analysis was performed on a small range of complimentary strained and relaxed samples, to investigate the hypothesis that strained SiGe alloys on Si(100) have shorter bond lengths than relaxed samples. The results of the analysis suggest that strain accommodation is at least partly accomplished by bond length contraction.

Finally, the Appendix details a complimentary project in near-edge x-ray absorption fine structure measurements of SiGe alloys. Specifically, a strain-induced polarisation dependence in the Si K-edge spectra of SiGe films is explored with measurements of a large range of samples. The results indicate that the source of the polarisation is not yet fully understood.

abstract: Master of Engineering (ME)


title: WOOD-POLYMER ALLOYS -- SOME FUNDAMENTAL CONSIDERATIONS

contributor:
Hodgins, J.W.
Chemical Engineering

subject:
Other Chemical Engineering
Other Chemical Engineering

abstract: An experimental investigation of graft copolymerization of styrene in wood was performed utilizing (1) Cobalt-60 radiation initiation, 2) impregnating solutions of styrene, methanol and water and (3) heat during the irradiation period. It was found that heating did not increase the grafting efficiency of the system. The grafting process was found to be dependent upon (1) the method of impregnation, (2) the density of the wood and (3) the amount of swelling agents in the impregnating solution. Wood treated with styrene and swelling agents was weakened in all mechanical properties except the maximum crushing strength and properties associated with compression. In genaral, wood treated with pure styrene was strengthened. It is felt that the use of radiation in the formation of wood-plastic composites is commercially unjustified.

abstract: Master of Engineering (ME)


title: Sedimentology of the Cardium Formation (Upper Cretaceous), Willesden Green Field, Alberta

subject: Geology Geology

abstract: Master of Science (MS)


title: Ethics and Ambiguity: A Critical Study of Charles E. Curran's Ecumenical Ethics of Dialogue

contributor:
Kroeker, Travis
Counsellor Education

subject: Education Education

abstract:
This study focuses on the social ethics of the Roman Catholic moral theologian Charles E. Curran (b. 1934). For more than four decades Curran has been one of the most influential voices in the renewal of Catholic moral theology in North America. Since the Second Vatican Council (1962-1965) the Roman Catholic Church has undergone changes of monumental proportion, impacting on the church's self-consciousness and requiring creative and unprecedented adjustments in its theology. The Council's commitment to "dialogue with the world" made the area of social ethics into a litmus test of the success of the church's reform. Charles Curran has developed an ethical-theological methodology, representing a revised approach to Aristotelian-Thomistic natural law theory, as a model for that dialogue with the world.

This thesis locates Curran's work in the context of the Vatican Council and of the social-ethics tradition of the Roman Catholic Church over the past one hundred years. Curran's critical response to these factors reveals the impulses and directions he develops in his methodology. His four-step method is explained in terms of its ethical and theological purposes and in relation to its intellectual roots in thinkers such as Bernard Lonergan and Karl Rahner. A major part of the thesis is devoted to four case studies, in which Curran applies his method to substantive, social-ethical questions.

This research identifies the strengths and weakness in Curran's method, pointing out the difficulty of melding a revised natural law method with the exigences of contemporary, empirical thought. The study makes recommendations for correcting inconsistencies and inadequacies of Curran's method along lines that are intellectually compatible with the work he has already completed.

abstract: Master of Education (MEd)


title: Experiments in International Finance

contributor:
Mestelman, Stuart
Economics / Economic Policy

subject: Economics Economics

abstract: This thesis contains three essays that are intended to be independent works. The essays all relate to applications of experimental methods to issues of international finance. The issues of experimental finance investigated are Rate of Return Parity and Currency Crises. The first essay investigates Rate of Return Parity using a laboratory environment in which two double auction asset markets are run simultaneously. Rate of Return Parity can then be used to predict the relative price of the assets in the two markets. The results of this experiment show that Rate of Return Parity is observed when assets are very similar and the exchange rate between the currencies in which the asset markets are denominated is perfectly fixed. The degree of Rate of Return Parity is reduced as the assets become dissimilar, or the exchange rate between currencies becomes unstable. The second essay employs robot asset traders to investigate some of the behavioural rules that subjects may have been using in the simultaneous asset markets of the first essay. The goal of the robot traders is to generate data that is qualitatively similar to that ofthe data generated in the experiment presented in the first essay. Ofthe various robot populations considered, profit maximizing robots that employ a weighted trend function in calculating the value of the asset combine with a single arbitrageur produce data that is most similar to that of human subjects. The third essay examines a laboratory environment in which a currency crisis is possible but not guaranteed. This was done using an environment similar to the one used to investigate Rate of Return Parity, with a fixed and known amount of reserves with which the fixed exchange rate would be defended. In the laboratory environment the exchange rate would change if the reserves fell to zero. In this manner whether or not there was a change in the exchange rate was completely under the control of the subjects. Results indicate that subjects are able to generate currency crises based on self-fulfilling prophecies. Overall the work of this thesis indicates that care should be taken when applying Rate of Return Parity to complex environments, and that the commitment of a central bank to defending a fixed exchange rate has an important role to play in determining if a currency crisis will occur.

abstract: Doctor of Social Science


title: PETROGRAPHY OF THE CARDIUM SANDSTONES IN THE RICINUS, CAROLINE, AND GARRINGTON FIELDS, ALBERTA

subject: Geology Geology

abstract: Seventy-nine thin sections were prepared from cores of the Upper Cretaceous Cardium sandstone, obtained from wells in the Ricinus, Caroline and Garrington fields in Alberta. Petrography of each thin section was studied to determine if any comparisons could be made between sands of differing fields, or between the Upper (A) Lower (B) sands of the same field. Two sandstone types have been determined based upon modal percentages of three major mineral constituents. A chert rich sublitharenite generally contains 60% chert,30% quartz, and 10% unstable rock fragments. A chert poor sublitharenite contains 70% quartz, 15% chert and 15% unstable rock fragments. The chert sublitharenite were coarse grained to conglomerate, poorly sorted, with subround to rounded grains. The chert poor sublitharenite were fined grained, well sorted, and contained subangular to angular gralns. Within the Caroline and Garrington fields, the Upper and Lower sands can be distinguished on the basis that the former is of the fine grained, chert poor sublitharenite type, and the latter is of the conglomeratic chert rich sublitharenite type of sandstone. The Lower Garrington sand can be distinguished from the Lower Caroline sand, because the Lower Garrington sand tends to be more chert rich. Similarly, the Upper Garrington sand and the Upper Caroline sand can be distinguished on the basis that the Upper Garrington sand contains a greater abundance of unstable rock fragments. The Upper sands of the Caroline and Garrington fields can not be distinguished from the Ricinus sand, whereas the Lower sands can, as they tend to be richer in chert, and are coarse grained to conglomeratic in grain size. The cementing sequence of; siderite, calcite and silica (in chronological order) was observed in all of the sands. Variations in cement abundances were a function of both depth and grain size. The deeper sands such as In the Ricinus field were predominantly silica cemented. The shallower sands tended to be siderite cemented, as did all those coarse grained to conglomeratic sands.

abstract: Master of Science (MS)


title: Migration and the Journey to Work in Toronto's Commuter Shed

contributor:
Scott, Darren M.
Newbold, Bruce K.
Geography

subject:
Commute distance
Migration
Residential location
Residential duration
Toronto
Human Geography
Transportation
Urban Studies and Planning
Human Geography

abstract: This thesis examines the relationship between migration, residential location, and commute distance within Toronto‟s commuter shed. The study utilizes data from the master file of the 2006 Canadian Census. This master file contains the previous residential locations of recent migrants, thus allowing migrants to be disaggregated by duration of residence. Multivariate regressions indicate that living in the most accessible rural areas and being a recent migrant are significantly associated with longer commutes. Furthermore, the Canadian Census distinguishes between those who migrated in the year immediately prior to the Census, and those who migrated one to five-years prior to the Census date. Findings demonstrate that the commute distance of very recent migrants (those who migrated in the year immediately prior to the census) have the longest commute distances. As residential duration increases, commute distance decreases.

abstract: Master of Arts (MA)


title: DEVELOPMENT OF AN APPARATUS FOR ULTRAFAST THz SPECTROSCOPY

contributor:
Haugen, Harold K.
Physics

subject: Physics Physics

abstract:
This thesis details the development of a multi-functional THz system capable
of operating in three different geometrical configurations: transmission, reflection
and attenuated total reflection (ATR). This apparatus can be used to collect THz
time-domain spectroscopic data or it can be used to study the carrier dynamics of a
system following optical excitation. These two functions categorize the two types of
experiments presented in this thesis.
THz time-domain spectroscopy (TDS) was performed with the transmission and
reflection configurations to determine the feasibility of using THz radiation to study
thin polymer films. This technique was also performed in an ATR configuration
with the use of a high purity Si prism. The THz ATR method was developed to
extend the capabilities of the system to accommodate liquid samples. '!\fater was the
primary sample of interest, however methanol, ethanol and sucrose solutions were
also examined. Although the results obtained regarding water are inconsistent with
the literature, it has led to valuable insight as to ho\', the current experimental setup
may be improved.
The optical-pump THz-probe technique was also incorporated \\ ith each of the
configurations of the system. In transmission mode, the carrier dynamics of ZnSe
nanowires were studied. In reflection mode, the optical-pump, THz-probe capabilities
were tested using a Si wafer sample. In the ATR configuration, the carrier dynamics
of the Si prism itself were examined. It is necessary to characterize the response of
the prism to optical excitation if this technique is to be applied to samples placed
on the surface of the prism. Efforts were made to control the free carrier lifetime of
the near surface region of the Si prism, by irradiating the surface of the prism with
a high energy proton beam to create defects in the Si. The results from this initial
experiment, along with suggestions for future follow-up experiments, are presented.

abstract: Master of Science (MS)


title: DESIGN OF A NOVEL ROBOTIC SURGICAL INSTRUMENT

contributor:
Bone, Gary M.
Mechanical Engineering

subject:
Mechanical Engineering
Mechanical Engineering

abstract:
Compared with traditionallaparoscopic surgery, robot-assisted surgery can return
all six degrees of freedom (DOF) to the surgeon, provide stereovision, filter tremors and increase precision for positioning and manoeuvring the surgical instruments. The
instruments used with commercially available surgical robots use external actuation in the form of relatively large motors located outside the patient with a cable transmission
system to bring rotation to the instrument's wrist. The goal of this research is to shift
away from the external actuation and design a surgical instrument that is internally
actuated. This is expected to miniaturize the overall device, enable instruments to be
created with a greater number of DOF than possible using the cable-driven approach,
enable the creation of modular designs with a "plug and play" capability and increase the precision ofposition and force control.
A novel internally-actuated instrument has been designed and prototyped using 6
mm DC motors and miniature transmissions. It features four DOF: an elbow joint, a roll
joint, and a wrist joint that employs two independently-actuated gripper jaws to allow for both rotation and grasping ability. The elbow joint is a unique feature that helps to avoid collisions with internal organs.
The design of the instrument has been explored in detail. After outlining the target
specifications of the device, justification is provided for the selection of the DC motors.
Additionally, the thermal properties of the motors have been examined to determine safe current limits. The design of the transmission mechanism (lead screw plus slider-crank) has been analysed and an optimization algorithm for the slider-crank parameters has been developed. Design calculations have been conducted to analyse the kinematics and static loading of the device and finite element analysis (FEA) has been executed to determine the stress concentrations due to the loading. Justification is also given for the component and material selection.
A prototype intended as a kinematic model has been manufactured and
assembled. The speed performance of the prototype has been tested using two methods: the first used video motion analysis to determine the average speeds of the elbow, roll and wrist joints; the second utilized a potentiometer to measure the instantaneous speed profile across the range of elbow joint motion. Overall, the elbow joint operated at an average speed of 2.0 rpm, the roll joint operated at 40 rpm, and the gripper jaws in the wrist operated at around 3.8 rpm. The potentiometer tests revealed that the joint performed in accordance with the theoretical speed profile, particularly when a correction factor was applied to account for the actual current that was drawn by the motor.
A force experiment was also conducted to confirm the torque capabilities of the
miniature brushed DC motor used in the prototype. Results showed that the motor,
attached to the lead screw and slider components of the elbow joint mechanism,
performed at about 15% efficiency. The motor was able to supply a torque of up to 4.2
mNm while maintaining an acceptable current level to avoid over-heating.

abstract: Master of Applied Science (MASc)


title: Thermodynamics of Stirling Type Engines for the Artificial Heart

contributor:
Sowerby, R.
Mechanical Engineering

abstract:
The thesis commences by tracing the underlying research work that established the feasibility and technically justified the current programmes for the development of the implantable artificial heart, more particularly those programmes based upon the use of a heat engine as the power unit of the artificial heart.

The provision of a heat source for the heat engine, whether it be a continuously generating source, such as a mass of a suitable radioisotope, or a thermally rechargeable material, adds to the burden of weight and bulk that the user must carry. This inconvenience could be reduced if the thermal efficiency of the engine can be increased. Thus, in the light of a heavy and probably an unending and continuously increasing demand for a practicable artificial heart the author considers that further work is justified if the engine efficiency can be raised, albeit by only a small amount.

The author's main endeavour is to identify an ideal engine cycle that appears to promise the most likelihood of high efficiency. It seems remarkable that there is little record of similar investigations readily available in the literature, and therefore, the present author has taken the approach to develop and evaluate parameters for a number of ideal cycles: Carnot, Stirling, Ericsson and the regenerative Otto cycle. The parameters for these cycles are compared, together with the published results for the Thermocompressor, the Schmidt isothermal and the Schmidt adiabatic cycles.

Working fluid mass distribution between the hot and cold spaces of the Schmidt isothermal engine is investigated, revealing the low utilization of the working fluid when large dead volumes occur in the engine. The hot volume versus cold volume relationships of the Schmidt and rhombic drive engines are analyzed and compared with the relationship for the true Stirling cycle.

Illustrations of the arrangement principles of historical and current "Stirling" engines, as well as the constructions of contemporary artificial heart engines are presented to indicate how problems of arrangement have been answered.

The main findings are:

(a) Of the isothermal cycles considered, i.e. cycles of potential Carnot efficiency, the true Stirling cycle is significantly the best and better than the adiabatic cycles.

(b) The ideal adiabatic cycles achieve efficiencies tending to the Carnot level as the compression ratio tends to unity. Working fluid utilization is least when the ideal efficiency is maximum, that is at unity compression ratio. Inevitable losses in the practical engine indicate that the maximum efficiency will be attained at a compression ratio significantly greater than unity.

(c) The effect of regenerator inefficiency in the Stirling engine can be partly compensated by increasing the compression ratio.

(d) The hot space-cold space relationships of the Schmidt and rhombic drive engines deviate significantly from those of the ideal Stirling cycle.

It is concluded that an engine built to run as closely as possible to the true Stirling cycle is the most promising route to the best attainable efficiency, also that in practice the compression ratio is likely to strongly influence the achievable efficiency.

The author recommends building an initial research engine with its hot-cold spatial relationships cam controlled to the requirements of the true Stirling cycle, also to be adjustable for comrpession ratio. The major purpose of this initial engine would be to prove the veracity or otherwise of the cycle selection and to determine how the efficiency varies in practice with compression ratio. For comparison, cams would also be made to stimulate other cycles, e.g. the Schmidt cycle. Suggestions are given for features that would facilitate the operation and performance measurement of the engine.

In presenting this work the author also considers that he has compiled a useful bibliography which contains the more pertinent references in the field.

abstract: Master of Engineering (ME)


title: Power Saving in Wireless LAN Localization Systems

contributor:
Todd, Terence D.
Electrical and Computer Engineering

subject:
Electrical and Computer Engineering
Electrical and Computer Engineering

abstract:
A localization system based on the Institute of Electrical and Electronics Engineers 802.11™ wireless local area network standard enables cost-effective localization measurements. It also integrates data dissemination within the system, unlike the popular NAVSTAR global positioning system. This thesis addresses two significant deficiencies in such a system: potentially low localization accuracy and high power usage of the communication infrastructure. A design for a low-cost solar powered localization augmentation node (SPLAN) is proposed to provide accuracy-increasing localization assistance service to localization tags-small battery powered units equipped with an IEEE 802.11 transceiver. Power saving network protocols for the SPLAN/ tag architecture are developed to extend the tag battery lifetime and allow the SPLAN to be cost-effectively supplied by renewable energy sources such as solar energy.
A comprehensive power consumption model is developed for two complementary communication systems: plain tag and smart tag. Through its use, significant SPLAN energy conservation for low tag densities was demonstrated in the plain tag system, while preserving legacy compatibility. In the smart tag system even greater energy gains were obtained for both the SPLAN and the smart tag, up to maximum supportable tag densities. This was possible through the use of a custom communication protocol designed specifically for smart tag system power saving. Two innovative aspects of the protocol include timing-assisted scanning of management beacon packets and an optimized procedure for dissemination of raw localization data.

abstract: Master of Applied Science (MASc)


title: Temporal Denoising of High Resolution Video

contributor:
Wu, Xiaolin
Dumitrescu, Sorina
Electrical and Computer Engineering

abstract:
This thesis is concerned with the removal or reduction of noises in high resolution
video sequences. Many video denoising techniques have been published in the past
two decades) with or without motion compensation. They vary in a wide range of
complexity) performance, and implementation cost. Also) many existing video denoisers make simplistic assumptions on noise statistics and motion type, and hence
their performance depends on the validity of the assumed noise and motion models.
To improve the performance and robustness of existing methods) we propose a new
joint spatial-temporal video denoising algorithm that combines multihypothesis interframe motion compensation and directional intra-frame filtering. The algorithm takes into account general compound motions, including both global camera motion and
individual object motion(s). An affine motion model is used to characterize the global
camera movement, whereas a blockwise translational motion model is used to approximate local object motions. Quadtree data structure is used to organize and speed up the computations of block-based motion estimation. Quadtree-structured diamond search is conducted so that a large area can be examined in motion estimation at a low computational cost.
In order to achieve the best possible visual quality we augment motion-compensated
temporal interframe denoising operation by an intra-frame denoising operation of
adaptive directional filtering. The directional filter is designed for the local signal
waveform and noise level, and it has the advantage of effectively suppressing noises
without blurring edges.
The proposed video denoising algorithm is implemented and tested extensively on
high-resolution digital cinema contents. The experimental results demonstrate the
competitive advantages of the new algorithm in both visual quality and processing
throughput.

abstract: Master of Applied Science (MASc)


title: TRANSIENT BEHAVIOUR IN GLUCOSE/OXYGEN BIOFUEL CELLS

contributor:
Xu, Gu
Materials Science and Engineering

subject:
Materials Science and Engineering
Materials Science and Engineering

abstract:
In this thesis, solutions to the problem of low power density caused by pH
deviation in anode and cathode of a glucose/oxygen based enzymatic fuel cell using GOx and FMCA are provided. Moreover, conclusive evidence of a large active area in this type of fuel cell is determined using a transient state study. The complete process of electrical double layers formation is described.
A survey of the solutions to low power density caused by pH deviation is conducted and two feasible alternatives are suggested. The first alternative, using Tris buffer with no alkaline ions resulted in even larger pH gradient. The second alternative: using anion exchange membrane (AEM) successfully reduced the pH gradient by introducing lower power density than the biofuel cells using a Nafion membrane. It was proven that the high internal resistance of the AEM is responsible for the drop in energy output ofthe biofuel cell.
A transient study was conducted on the biofuel cells in order to investigate the
internal resistance of the components. A discrepancy was found when applying the
rarely-mentioned internal circuit model to biofuel cells. The model predicted a much
larger surface area for the electrode than was physically measured for the cells. It is
therefore concluded that the proposed electrochemical double layers are in the electrolyte as well as on the interface. Finally, a detailed description of electron/proton double layer in the electrolyte associated with each reaction step is given, assuming that double layers can be found on the enzymes and mediators.
A complete list of requirements for equivalent circuit is portrayed for our glucose/oxygen enzymatic biofuel cell. The equivalent circuit suggests a possible
direction for future biofuel cell research.

abstract: Master of Applied Science (MASc)


title: Narrow-Band Receiver and Ultra-Wideband Low Noise Amplifier

contributor:
Deen, Jamal M.
Electrical and Computer Engineering

abstract:
In past years, the evolution in communication technology has led to a need for
highly-integrated, low-power, and low-cost circuit designs for wireless applications.
The demand for radio frequency (RF) wireless transceiver operating at 2.4GHz
band has attracted considerable research interest. The performance of such
transceivers depends heavily on that of each of the individual blocks such as lownoise
amplifiers and mixers. However, there are very few designs that focus on
connecting the single-ended output low-noise amplifier (LNA) to a double-balanced
mixer without the use of on-chip transformer. This kind of receiver front-end is designed
to achieve high integration and low power consumption.
In recent years, Ultra-Wideband (UWB) technology has developed very rapidly
due to its high data transmitting rate and low power consumption. Meanwhile, the
design of an Ultra-Wideband low-noise amplifier (LNA) has become an important
challenge since it is normally the front-end of the radio frequency (RF) receiver system.
Low power consumption of an UWB LNA is a critical requirement for UWB
application such as portable devices or especially in biomedical systems. However,
the design should not only focus on low power, but also focus on optimizing other
performances at competitive levels over the entire bandwidth, where the Federal
Communication Commission (FCC) has allocated 7.5 GHz of bandwidth from 3.1GHz to 10.6 GHz for Ultra-Wideband.
This thesis focuses on the design of a fully-integrated RF receiver front-end including
a narrow-band LNA followed by a double balanced mixer. The receiver operates at 2.4 GHz and produces an output signal at 300 MHz. The circuit is designed and fabricated using TSMC O.lS-p,mCMOS technology. In order to translate the single-ended RF output signal from the LNA into the differential input pair of the mixer, a main novel idea of this design is to use one PMOS and one NMOS instead of two NMOS devices for the RF amplification stage of the double balanced mixer. The circuit achieves 16.3dB gain and 6.74mW power consumption while using 2.08 mm2 chip area.
Another design presented in this thesis is a UWB LNA with special emphasize
on low power consumption as well as on optimizing the overall performance. The
circuit is designed using TSMC 0.13-p,m CMOS technology. It achieves a very flat
gain of 10.3-12.1 dB and 3.4-5.9 dB noise figure (NF) throughout the entire bandwidth
of 3.1-10.6 GHz. The power consumption is 2.81 mWwhich is extremely low compared to other designs and the chip area is 0.48mm2 • The overall performance is also competitive according to its figure of merit (FoM).

abstract: Master of Applied Science (MASc)


title: THE EFFECT OF MICROSTRUCTURE ON THE STRAIN LOCALIZATION IN COARSEGRAINED AA5754 SHEETS

contributor:
Wilkinson, David S.
Materials Science and Engineering

abstract:
AI-Mg sheets (5xxx series) for body-in-white (BIW) application are mostly
used for automotive structural parts due to their specific combination of
formability and strength. The limiting behavior for the wide application of AA5754
sheets is strain localization. The effect of microstructure inhomogeneties on
strain localization have recently been attracting a great deal of interest but not
fully understood. In this present work, the effect of grain-level microstructure
inhomogeneties in AA 5754 sheets is investigated.
Uniaxial tensile experiments combined with two 2-dimensional Digital
image correlation (DIG) techniques have been performed on coarse-grained
specimens to evaluate the deformations of individual grains. Grain orientations
and their evolution were measured by the electron backscattered diffraction
(EBSD) technique, and surface features such as slip traces were observed by
optical microscopy.
The regions of high local strain ('hot spots') within coarse-grained samples
nucleate at a very early stage of deformation and most of them continuously
grow throughout most deformation stages. 'Hot spots' are correlated with 'soft'
grains (i.e. grains with high Schmid factors) and soft-evolution grains (i.e. grains
with the <101> direction close to tensile axis).

abstract: Master of Applied Science (MASc)


title: SIMULATINGTHE UNSTEADY HYDRODYNAMICS OF A ROWING OAR BLADE

contributor:
Tullis, Stephen
Mechanical Engineering

abstract:
The highly unsteady free surface flow around a rowing oar blade in motion is
investigated using modelling techniques. The ability of the numerical model to replicate
this complex flow is demonstrated by using computational fluid dynamics (CFD) to
simulate previously performed steady-state experiments involving a qum1er-scale rowing blade in a water flume. A comparison of drag and lift coefficients from the experiments and the simulations reveals excellent agreement, providing confidence in the numerical model to handle similar flow conditions. The computational domain is then expanded to simulate a full-scale blade in open water conditions, and steady-state drag and lift coefficients are compared to those previously simulated for a qum1er-scale blade in a flume, revealing substantial differences in magnitude. The computational domain is then modified to allow for oar rotation, as in actual rowing. A force-based rowing model is derived, calculating the instantaneous velocity of a shell based on the propulsive force generated by the motion of the oar blade in the water, the hydrodynamic drag on the shell, and the motion of the rowers within the shell. Using the shell velocity and a prescribed oar angular velocity, the CFD model calculates the highly unsteady blade flow, providing instantaneous drag, lift, and propulsive forces on the blade, in tum driving the rowing model.

The dynamic blade-water interaction is depicted in six distinct flow regimes,
characterized by the relative motion of the blade in the water and the temporal influence of drag and lift. It is seen that the propulsive force generated by the blade is largely liftinduced through the first half of the stroke. During the middle of the stroke, drag increasingly influences the propulsive force. At end of the stroke, the propulsive force is once again largely lift-induced.

abstract: Master of Applied Science (MASc)


title: The routine use of the Canadian Occupational Performance Measure by Occupational Therapists: Effect on practice, outcomes and therapists' perceptions of use

contributor:
Letts, Dr Lori
Rehabilitation Science

subject:
Routine outcome measurement
clinical utility
clinical practice
Functional Independence Measure
Occupational Therapy
Occupational Therapy

abstract:
This thesis focuses on routine outcome measurement in occupational therapy; specifically the use of the Canadian Occupational Performance Measure (COPM) in inpatient geriatric rehabilitation.

The purpose of the first study (Chapters two and three) was to: 1) determine if routine COPM use was associated with improved functional outcome; 2) gather therapist perceptions on routine COPM use; and, 3) propose a template for summarizing COPM data. A cohort study with a therapist participant survey measured the difference in Functional Independence Measure (FIM™) change scores between an experimental group (n = 45) that implemented the routine use of the COPM for evaluation/planning and a historical “usual care” comparison group (n = 58). Using generalized linear modeling, it was found that both groups had significant changes in FIM™ scores over time (p <. 05). Differences between groups were not significant. Therapists perceived that the COPM facilitated treatment but experienced challenges in routine use. Therapists placed more importance on individual than group data.

The second study (Chapter four) determined if routine use of the COPM was associated with changes in five domains of practice: focus of care on occupation, knowledge of client perspective, clinical decision-making, clinician ability to articulate outcomes, and documentation. Twenty-four occupational therapists on eight geriatric rehabilitation units completed a before-and-after study with a repeated baseline. Domains of practice during three months of standard care (no COPM) were compared using Chart Stimulated Recall and chart audit as outcome measures to three months of intervention (COPM). Mean practice scores indicated a significant effect for time (p < .0001) but no effect based on the frequency of COPM use. Chart audit indicated that COPM use resulted in more occupation-focused issue identification.

This thesis challenges assumptions regarding the value of measurement and contains the first study to demonstrate that routine outcome measure use affects occupational therapy practice.

abstract: Doctor of Philosophy (PhD)


title: A FRAMEWORK FOR INTEGRATED REACTIVE SCHEDULING OF PLANT OPERATIONS AND MAINTENANCE

contributor:
Marlin, T.E.
Chemical Engineering

abstract:
This thesis addresses a reactive (closed-loop) scheduling framework for integrated
scheduling of process operation and maintenance. Ethylene plant furnace scheduling is
chosen as the process example because it is concerned with optimally scheduling the
furnace operations and its periodic maintenance shutdowns. The main reason for
choosing this example is that it addresses a special class of scheduling problems where
the operations and maintenance have strong interactions and so integrated decision
making becomes necessary.

The major goal of this research was to select an appropriate closed-loop
framework and develop a reactive scheduling system. With the rolling horizon approach
being the most suitable method for closed-loop schedule implementation, a Model
Predictive Control (MPC) framework is chosen in this thesis. The presence of integer
variables in the scheduling model made the reactive scheduling systems resemble a
hybrid MPC problem.

The research was performed in two phases. In the first phase, an open-loop
scheduling model was formulated as a Mixed Integer Linear programming problem
(MILP) using discrete time representation. To ensure the tractability of the model,
tailored formulation methods (disjunctive reactor modelling, constraint reformulation and tightening constraints) and efficient solution heuristics (two-stage temporal
decomposition heuristic) were developed in this thesis. In the second phase, the openloop scheduling model was applied in the prototype closed-loop framework to develop a reactive scheduling system to assist engineers make appropriate decisions in a timely manner.

The automated scheduling system developed in this thesis was tested for several
scenarios and proved to have significant benefits over manual scheduling procedures,
confirmed that the scheduling model is tractable and achieved feasible solutions for all
the scenarios considered, including large problems with multiple feeds, multiple reactors and a long (90-day) scheduling horizon. We conclude that the technology is appropriate for further improvement and eventual application in the industry.

abstract: Master of Applied Science (MASc)


title: The conflict of thermogenic responses in CD-l mice to chronic hypoxic and cold environments

contributor:
McClelland, Grant B.
Biology

subject: Biology Biology

abstract:
Surviving at high-altitudes requires organisms to endure the combined
stresses of cold temperature and low atmospheric oxygen. Maintaining a stable
body temperature (Tb) is a constant battle that endotherms must defend when they
are subjected to temperatures beyond their thermal neutral zones (TNZ). Once
outside their TNZ, they elicit mechanisms of adaptive thermogenesis which
stimulate heat production via non-shivering (NST) and shivering thermogenesis
(ST). These processes are carried out in brown adipose tissue (BAT) and skeletal
muscle, respectively. Uncoupling proteins (UCP) carry out mechanisms of NST
by uncoupling substrate oxidation from ATP synthesis to generate heat. Many
studies have examined responses in endotherms to cold temperature acclimations
as well as episodes of acute hypoxia. However very few studies have looked at
the chronic effects of hypoxia and even less have investigated the combined
. effects of cold and hypoxia acclimations. Therefore, to address this issue we
examined the chronic effect of four weeks of exposure to hypobaric hypoxia (H,
480mmHg), cold (C, SOC) and the combination of the two stressors (HC)
compared to normoxic thermoneutral controls (N, 28°C) in CD-l mice. Overall
we found that HC mice had significantly lower Tb after periods of acclimation
while still residing in hypoxia compared to all other treatment groups. However,
experiments during acute temperature exposures in normoxia revealed that HC
mice were able to increase Tb as well as they demonstrated higher rates of thermal
conductance at high ambient temperatures. Investigations into BAT and UCP
regulation revealed that HC had a greater amount of BAT mass compared to controls and lower UCPl mRNA expression in BAT but no differences in UCPl
protein content. However, HC had lower mitochondrial density indicated by
lower activity of citrate synthase in BAT as well as UCP3 mRNA expression.
Together results from cold mice suggest that they exhibit an enhanced NST
capacity through the up-regulation of BAT mass and UCPl mRNA expression
whereas hypoxia inhibits NST response by down-regulation of UCPl and
mitochondrial density. Moreover the acclimation to both hypoxia and cold may
create barriers on an animal's ability to up-regulate NST in hypoxia by decreasing
mitochondrial density, UCPl and 3 mRNA expressions but still allows BAT
mechanisms to generate heat through UCPl protein that regulates Tbin normoxia.

abstract: Master of Science (MS)


title: Measurement of Molecular Weight Distribution of Polyacrylamide By Turbidimetric Titration

contributor:
Hamielec, A.E.
Brash, J.L.
Chemical Engineering

abstract:
This thesis reports on a method for measuring the molecular weight distributions of polyacrylamide - a water-soluble polymer. The method which is turbidimetric titration involves the incremental addition of non-solvent or precipitant to a solution of polymer and encourages aggregation. At each point of the titration, optimum condition was obtained. The optimum condition was defined by proper application of Mie theory of light scattering functions. These scattering coefficients and scattering functions were further investigated over a broad range of particle size. Broad polymers were investigated, as this polymer-polyacrylamide can only be made via free-radical polymerization. The conditions necessary to satisfy the inherent assumptions were specified and justified by the experimental technique. A very high molecular weight polymer was polymerized by free radical polymerization in the presence of an electrolyte. The influence of electrolyte, and the method of mixing were studied.

The quality of the distributions and averages obtained by the method was assessed by GPC measurements and viscosity measurements. The method is capable of giving accurately the molecular weight distributions of any polymer in principle, especially when the weight average molecular weight is greater than five million.

abstract: Master of Engineering (ME)


title: A STUDY OF IRON POWDER COMPACTION FOR AUTOMOBILE COMPONENTS APPLICATION

contributor:
Jain, Mukesh K.
Mechanical Engineering

abstract:
The major advantage of the Powder Metallurgical (P/M) manufacturing
process is its ability to shape powder directly into a final component form with a
primary goal of a high quality, homogeneity of density and mechanical properties
and productivity. In this research, powder die filling, powder transfer and powder
compaction process have been studied in succession using a novel experimental
set-up that utilizes a high strength transparent wall section to observe and record
the particle movement and powder compaction during the entire sequence
leading up to the formation of a green part. The natural powder pattern itself, as
observed from the transparent wall section, is utilized for obtaining full-field
displacement and strain measurement for the first time. This strain field data is
converted into density distribution data and is validated through other commonly
used density measurement methods. The test set-up and the strain
measurement technique offer a means of quickly obtaining density distribution
data in select cases. In addition to the above, several powder flow characteristics
during die filling, powder transfer and powder compaction under a range of test
conditions have been noted through a series of high-speed photographic
recordings. The role of transfer speed and friction in the development of density
gradient and crack formation has been experimentally assessed. Another new
method of density measurement based on surface roughness of the compact has
been investigated. Finally, powder compaction simulations of the lab-based
experiments have been carried out using modified Drucker-Prager Cap model
within the ABAQUS CAE. The simulation results are in good agreement with
experimental data.

abstract: Master of Applied Science (MASc)


title: Short-Length Raptor Codes for Free-Space Optical Communications

contributor:
Hranilovic, Steve
Electrical and Computer Engineering

abstract:
Free-space optical (FSO) links are competitive wireless links offering high data rate,
security and low system complexity. Compared to radio-frequency (RF) links, FSO
links offer high rates at gigabit-per-second (Gbps) level and relatively low cost. However, atmospheric scintillation and misalignment between optical transmitter and receiver impair data rates of FSO links. Scintillation and misalignment are slow fading
processes with a fading interval of 10's ms. Conventional fixed-length channel coding
which interleave data blocks are unrealistic to overcome this slow fading due to block
length of 10's of megabits. Also, because of the Gbps data rate, data rate adaptation
to channel conditions are expensive.
In this work, short-length (16 - 1024) Raptor codes are designed to overcome the
slow fading of FSO channels. These Raptor codes are applied at the packet-level with
high data rate and low decoding complexity. The Raptor encoder and decoder can be
easily implemented in any software or hardware form. The practicality of these Raptor
codes is demonstrated by a Raptor encoder and decoder which are implemented in
field-programmable gate array (FPGA) and shown to support a 1.22 Gbps encoding
and 714 Mbps decoding rate with a 97 mW low power consumption and 26360 gate
circuit scale. High-speed transmission at Gbps level is easily satisfied by the same
design implemented in an application-specific integrated circuit (ASIC).

Two applications of these short-length Raptor codes in FSO links are presented
in this work. Firstly, these Raptor codes are applied to hybrid FSO/RF links to
achieve high data rate by sending Raptor encoded packets simultaneously over the
FSO and RF links which we term such links as Raptor-coded soft-switching hybrid
FSO/RF links. The performance of these Raptor codes in the hybrid FSO/RF links
is simulated in a realistic channel model based on climate data of three Canadian
cities. For a 1 Gbps FSO link combined with a 96 Mbps WiMAX RF link, the softswitching
system achieves an average rate of 472 Mbps using the implemented Raptor
code while hard-switching technique achieves only 112 Mbps on average.
Secondly, these Raptor codes are applied in mobile FSO links for an unmanned
aerial vehicle (DAV). This mobile FSO link suffers from severe instantaneous misalignment. For packet-level transmission, the time varying misalignment is unknown
to the transmitter and causes data packet corruption and erasure. As a result, the
application of conventional fixed-rate erasure coding techniques is difficult. In this
work, short-length Raptor codes are applied in such mobile FSO channels. A key advantage of Raptor codes is their independence on channel state, no matter how large
the misalignment. With a 1 Gbps transmitter, the designed Raptor code with k = 64
message packets offers 650 Mbps data rate when transmitting power is 20 dEmo In
contrast, a traditional automatic repeat-request (ARQ) algorithm technique on the
same FSO jitter channel achieves a rate of 70 JVlbps.

abstract: Master of Applied Science (MASc)