title: The regulation of cell-cell adhesion by monohydroxy lipoxygenase metabolites

contributor:
Buchanan, M.R.
Medical Sciences

subject:
Medical Sciences
Medical Sciences

abstract: Cell-cell adhesion is an important and an initiating event in thrombosis, inflammation and metastasis. Recent data suggest that these adhesion events are mediated by cell adhesion receptors and/or ligands present on blood cells, the endothelium and the basement membrane underlying the endothelium. This thesis hypothesizes that endogenous lipoxygenase metabolites regulate blood cell-vessel wall interactions. The following data, as presented in this thesis, support this hypothesis. First, the intracellular level of 13-HODE in endothelial cells, inversely correlated with platelet, tumor cell and leukocyte adhesion. Second, intracellular 13-HODE levels and/or 13-HODE:HETE ratios in blood cells and in tumor cells also inversely correlated with cell adhesivity. Third, the level of 13-HODE in basement membranes and in artificial grafts, inversely correlated with platelet adhesion. Fourth, 13-HODE co-localized with the vitronectin receptor (VnR) in resting endothelial cells. Following stimulation, 13-HODE and the VnR dissociated, and the VnR relocated to the periphery surface of the endothelial cell. Fifth, the increased peripheral expression of the VnR on stimulated endothelial cells mediated platelet adhesion. Finally modulation of the lipoxygenase pathway markedly influenced experimentally-induced thrombosis. In summary, there is an abundance of data presented in this thesis which suggest that monohydroxy lipoxygenase metabolites regulate blood cell-vessel wall adhesion. This regulation appears to be a result of lipoxygenase metabolites influencing adhesion receptor/ligand recognition. Therefore, it is a reasonable expectation that agents which modulate the lipoxygenase pathway may also be useful in the prevention and treatment of thrombosis, inflammation, and metastasis.

abstract: Doctor of Philosophy (PhD)


title: Sedimentology and allostratigraphy of regional, valley-fill, shoreface and transgressive deposits of the Viking Formation (Lower Cretaceous), central Alberta

contributor:
Walker, R.G.
Geology

subject: Geology Geology

abstract: The Viking Formation (Upper Albian) is overlain by the marine mudstones of the Lower Colorado shales and is underlain by the marine mudstones of the Joli Fou Formation. The Viking sediments form a third-order regressive-transgressive cycle that can be correlated with the global sea level curve, specifically with the third-order eustatic fall and rise of sea level at 97-98 Ma. The absolute duration of the Viking is estimated at 1.2 million years. The sediments of the Viking are subdivided into four different packages; regional, valley-fill, shoreface and transgressive deposits. The packages are separated by bounding discontinuities labelled VE2, VE3 and VE4. The regional deposits consist of bioturbated mudstones, siltstones and sandstones, forming 12 coarsening-upward, shelf to shoreface successions. These deposits form a progradational parasequence set that off laps towards the east. Regional shoreline trends are oriented N-S or NNE-SSW. A large relative fall in sea level followed the deposition of the regional deposits. It was triggered by the 98 Ma eustatic fall in sea level, and was enhanced by uplift in southwestern Alberta. This sea level fall resulted in the cutting of the VE2 erosion surface, reorientation of the Viking shoreline trends to NW-SE and introduction of coarse-grained sediments into the study area. Deposits filling the lowstand incised valleys are located at Crystal, Cyn-Pem, Sundance and Edson. A first phase of incision took place during the "VE2" lowstand, and a second phase of incision and filling occurred during the "VE3" transgression. The valley-fill deposits consist of conglomerates sandstones and mudstones. Tripartite facies geometries (sand-mud-sand) exist in the Crystal, Sundance and Edson valley-fill deposits. Shoreface deposits related to the VE3 transgression are located along the Joarcam, Sunnybrook "B", Sunnybrook "A", Chigwell, Wolf Creek/Gilby-Joffre, Bickerdike and Caroline-Garrington trends. The shoreface sediments were deposited during stillstands and regressions that were superimposed onto the "VE3" transgression. They consist of bioturbated mudstones and sandstones, and are oriented NW-SE. The transgressive deposits occur in localized patches and are the uppermost sediments of the Viking. These sediments consist of thinly bedded mudstones, siltstones, sandstones and conglomerates, and were deposited during the latter stages of the "VE3" transgression. The Viking sediments consist of 19 parasequences; 12 regional cycles and 7 shoreface cycles. Each parasequence was deposited in approximately 63,000 years. This cyclicity may have been caused by glacio-eustatic mechanisms, differential subsidence or autocyclic processes; the exact mechanism or combination of mechanisms that produced this cyclicity is unknown.

abstract: Doctor of Philosophy (PhD)


title: Sir Thomas Malory and the English gentry: Romance, society, identity

contributor:
Braswell, Laurel
English

subject:
English Language and Literature
English Language and Literature

abstract: Due in part to romantic, epochal theories of history, Sir Thomas Malory has conventionally been thought of as the last voice of authentic feudalism and of traditional chivalry. This thesis challenges that reputation of the nostalgic writer, and argues that his work reflects the social mobility that was transforming England's landed class in the late Middle Ages, when knighthood was in decline, and the identity of gentleman were becoming correspondingly more important. Through the term "gentry writer", the thesis attempts to link Malory more closely with the readers and writers of English romances, as represented by the many unadorned manuscripts of provincial provenance. Typically the heroes of these romances carve out successful careers at the expense of haughty lords and mean-spirited burgesses, and in the process demonstrate that their honour and virtue are individual qualities, not necessarily dependent on the office of knighthood. While the theme of social mobility and careerism has been noted as a theme of Middle English romance, its prominence within Malory's work has received little attention. This thesis finds that the standards by which Malory judges his heroes are not prowess or martial ability so much as a combination of ethical and moral qualities which he calls "jantylnesse". Gentleness is exemplified by the great knights such as Lancelot and Tristram, but is also the cause for the success of the numerous Fair Unknowns who come to Arthur's court. In determining that Malory ultimately regards his characters as independent gentlemen rather than as extensions of a corporate identity, the thesis concludes that Malory's work reflects the same desire to define an honourable and individual identity which is seen in the romances, courtesy books, and correspondence of the gentry.

abstract: Doctor of Philosophy (PhD)


title: Sir John Beverley Robinson: A colonial judge and the development of Upper Canadian law

contributor:
Weaver, John C.
History

subject: History History

abstract: This dissertation analyzes the judicial career of Sir John Beverley Robinson, Chief Justice of the Court of Queen's Bench (1829-1862) for Upper Canada. Robinson's tenure spanned much of the history of the colony before Confederation. During this time the formation of new corporate interests, steam technology, public works in transportation and urbanization affected the economy and the social relations in the colony. New developments had an impact on the law. This study eyes four areas of Robinson's jurisprudence relating to this transitional era: the reception of English law into Upper Canada, the early development of corporate law, business law pertaining to the commercial development of the St. Lawrence and the initial stages of railway law. In addition, Robinson's jurisprudence is contrasted with contemporary American law. The central argument here is that Robinson's jurisprudence was different from that of American judges, and especialIy with regards to instrumentalism. The thesis argues that these differences can best be understood by relating Robinson's career to unique political, social, economic and other particularities within Upper Canada prior to Confederation.

abstract: Doctor of Philosophy (PhD)


title: Magnetoelastic effects in Europium Chalcogenides

contributor:
Goodings, D. A.
Physics

subject: Physics Physics

abstract: The theory of magnetoelastic interactions is described for ferromagnetic crystals with cubic symmetry and is applied to the europium chalcogenide series. The expressions for the change of elastic constants as a function of applied magnetic field are written down. Using available data on anisotropy and magnetostriction, the crystal field parameters and the magnetoelastic constants are estimated for europium oxide. The fractional change in the measured elastic constant C44 is predicted to be 5x10^-4 in an applied field of 25 k0e.

abstract: Master of Science (MS)


title: Properties of distance functions and minisum location models

contributor:
Love, R.F.
Management Science/Systems

subject: Management Sciene/Systems

subject: Management Sciences and Quantitative Methods

abstract: This study is divided into two main parts. The first section deals with mathematical properties of distance functions. The ℓp norm is analyzed as a function of its parameter p, leading to useful insights for fitting this distance measure to a transportation network. Properties of round norms are derived, which allow us later to generalize some well-known results. The properties of a norm raised to a power are also investigated, and these prove useful in our subsequent analysis of location problems with economies or dis-economies of scale. A positive linear combination of the Euclidean and the rectangular distance measures, which we term the weighted one-two norm, is introduced. This distance function provides a linear regression model with interesting implications on the characterization of transportation networks. A directional bias function is defined, and examined in detail for the ℓp and weighted one-two norms. In the second part of this study, several properties are derived for various forms of the continuous minisum location model. The Weiszfeld iterative solution procedure for the standard Weber problem with ℓp distances is also examined, and global and local convergence results obtained. These results are extended to the mixed-norm problem. In addition, optimally criteria are derived at non-differentiable points of the objective function.

abstract: Doctor of Philosophy (PhD)


title: Investigations of chemosensory mechanisms in cultured glomus cells of the rat carotid body using patch clamp/whole-cell recording

contributor:
Nurse, Colin A.
Biology

subject: Biology Biology

abstract: The mammalian carotid body is a small chemosensory organ, located at the carotid bifurication which senses blood levels of oxygen, carbon dioxide, and acidity and controls breathing. In response to these chemosensory stimuli nerve impulses emanating from the carotid body are conveyed along the carotid sinus nerve and forward information to the respiratory control centre in the brainstem. The chemosensors in the carotid body were presumed to be the glomus or type I cells, which contain neurotransmitters and receive a direct sensory innervation, although relatively little is known about their physiology. The goals of this thesis were to characterize the electrophysiological properties of glomus cells from the rat carotid body and determine if they are modified by exposure to the chemosensory stimuli. The use of cell cultures of dissociated carotid bodies allowed virtual isolation of glomus cells making them accessible for study by the modern electrophysiological patch clamp/whole-cell technique. This high resolution method is ideally suited for electrophysiological recording from small cells (such as the glomus cells) and allows the measurement of current flow through single ion-channel proteins. Whole-cell recording from glomus cells under voltage clamp revealed the presence of voltage-activated Na⁺, K⁺, and Ca²⁺ currents as well as leakage anion (Cl⁻/HCO₃⁺) channels which were unmasked in physiological bicarbonate/CO₂-containing media. Acute exposure to hypoxia (Po₂≈20-30 Torr) caused a selective suppression of K⁺ currents in glomus cells while chronic exposure (up to 2 weeks) to hypoxia (Po₂≈50 Torr) promoted the selective induction of Na⁺ channels and caused hypertrophy of these cells. Both these effects appear to be mediated via the second messenger cAMP and may account for the increased sensitivity and enlargement of the carotid body following chronic hypoxia. The other chemosensory stimuli, extracellular acidification and hypercapnia, decreased both Na⁺ and K⁺ currents in glomus cells. The effects of both these stimuli were likely mediated via cytoplasmic acidification as directly lowering pHᵢ had similar effects on the membrane currents and carbonic anhydrase activity, which is present in these cells cytoplasm, is known to cause acidification in the presence of CO₂. A discussion of the intrinsic physiological mechanisms of chemotransduction by glomus cells revolves around modulations of the voltage-activated K⁺, and Na⁺ currents during chemosensory stimulation causing alterations in intracellular Ca²⁺ and pH. These changes in Ca²⁺ᵢ and pHᵢ cause neurotransmitter release onto the sensory nerve endings finally leading to increased breathing by a reflex pathway through the respiratory control centre in the brainstem.

abstract: Doctor of Philosophy (PhD)


title: Application of the finite element method to laminated fiber composites

contributor:
Dokainish, M. A.
Mechanical Engineering

subject:
Mechanical Engineering
Mechanical Engineering

abstract: This thesis deals with the application of the Finite Element Method to the analysis of laminated fiber composites. Specifically, it addresses the problem of representing the variation of material properties through the element volume in order to reduce the number of degrees of freedom required to represent a laminated composite. This is accomplished by a modification in the evaluation of the element stiffness matrix, whereby the through thickness integration is evaluated separately for each ply of the laminate. This modification results in a significant reduction in the core memory requirements. The modification is implemented in a finite element code and used to investigate various aspects of laminate behaviour using a design philosophy based upon the laminae constituents rather than the more usual laminate properties. Problems involving lamina coupling, edge and surface deformations are solved for symmetric and unsymmetric laminates. The tensile behaviour of a particular laminate is predicted, and the ability to back calculate the specimen composition parameters is demonstrated. An explanation of the specimen size limitation for tensile tests is verified. Views of plate edge deformations are obtained that are not predicted by classical laminated plate theory, and that are currently unavailable in the literature. The modified element formulation is also used to implement a method whereby laminates of various lamination sequences may be ranked in terms of their energy absorption potential when subjected to quasistatic loading conditions by comparing the total energy absorbed before catastrophic failure. This is accomplished by the used of a damage analysis method that is based upon element integration point failure rather than the usual first ply failure criterion.

abstract: Doctor of Philosophy (PhD)


title: "The key-stone of the arch": Coleridge's metaphor of joining and some of its consequences

contributor:
Vince, R. W.
English

abstract: The thesis examines the implications of Coleridge's claim that in the philosophy of Johann Gottlieb Fichte he had discovered the "key-stone of the arch"--a connection, in other words, between materialist and idealist ways of conceiving the world. Since a purely Fichtean philosophy seems to generate an unbridled will set over against a passive world, and to culminate in a technological attitude towards both nature and the products of human activity, the various schools of literary criticism that trace their origins to Coleridge have, to a certain extent, inherited a fascination with will and with technique. But while Coleridge undoubtedly appreciated the philosophic significance of Fichte's conception of a foundational act of self-positing, he diverges from Fichte on the proper uses of the human will. Rather than regarding the world as simply an arena in which the will exerts itself in opposition to nature, Coleridge works his way toward a dialectical philosophy in which human consciousness and nature cooperate and are reconciled. In his understanding of the dialectic as both a formal method and a way of accounting for human history, Coleridge resembles the philosopher G. W. F. Hegel more than has previously been acknowledged.

abstract: Doctor of Philosophy (PhD)


title: Local effects in rectangular hollow section joints

contributor: Civil Engineering and Engineering Mechanics

subject: civil engineering and engineering mechanics

subject: Civil Engineering

subject: Civil Engineering

abstract: A theoretical and experimental study of RHS joints is presented, with particular attention being devoted to RHS gap K joints due to their popularity and complex behaviour. The theoretical aspects include the derivation of a nine-node general shell element with six degrees of freedom per node, capable of modelling multiple intersections between plates and shells. The material behaviour is described using the Von Mises yield criterion and the Prandtl-Reuss flow equations. The plasticity algorithm allows a sampling point to yield within a load increment and traces both the elastic and inelastic stress increments accordingly. Refined numerical analyses allow for an accurate tracing of the yield surface in every iteration. Each sampling point within an element is capable of carrying individually specified material properties. This makes it possible to account for a strain-hardened zone near the corners of an RHS or for the material properties of the weldment. The experimental investigation included 26 isolated RHS joints which were subconfigurations of a gap K joint. The testing program made it feasible to assess the effects of the angle of branch inclination and the flexibility of the base. Numerous strain gauges and rosettes mounted on the branch walls near the weldment, provided load-strain characteristics at the toe, the heel and the sidewall for the entire history of loading. The effectiveness of the heel area and the type of failure mode were found to depend strongly on the angle of branch inclination. The rigid or flexible base conditions affected the stress distribution in the branch walls and the direction of the principal axes. The developed finite element model was used in the numerical simulation of the behaviour of RHS joints. All the joint configurations tested were subjects of the numerical simulation in three independent stages which allowed for the model to be thoroughly verified. A very good agreement between the experimental and numerical results was achieved in all stages. The numerical analysis provided complementary results towards better understanding of the behaviour of tested joints. The same numerical model was utilized in a parametric study of a gap K joint which included the effects of : the angle of branch inclination, the width ratio, the gap size and the chord width to thickness ratio. The results are presented by means of stresses in the branch member walls and the local deflections of the chord connecting face. A number of new observations are made which result in recommendations for the design of RHS joints.

abstract: Doctor of Philosophy (PhD)


title: Electron-Beam Gun System for Electron-Capture Rate-Coefficient Measurement

contributor:
Ballik, E.A.
Physics

subject: Physics Physics

abstract:
A simple, pulsed, relativistic electron-beam gun has been built to measure electron attachment rates. The high voltage pulse (100KV) is provided by a spiral generator initially charged to 10KV. The electron-beam is formed by a lead (Pb) cathode vacuum-diode. The resulting electron-beam pulse has an energy of 90KeV per electron, a peak current density at the anode center of 175 A/cm², and a duration of 12 ns (FWHM).

The electron-beam is injected through a 26-μm thick aluminum foil into a gas mixture located in an electric field. By placing suitable screens in front of the beam, the injected electron-beam current-density is reduced to 1-2 A/cm². This results in an electron density in the plasma (produced by the primary electrons injected in an atmospheric-pressure gas mixture) which is typically 10¹³ cm⁻³. The electric field applied across the plasma is maintained constant (within 0.2%) by means of a storage capacitor (1μF). Rate coefficients of electron-capture reactions are determined by observing the temporal evolution of the induced discharge current pulse.

The system was used to measure electron dissociative-attachment rate coefficient for HCl as a function of the reduced field E/N, in both Ar-HCl and Ar-N₂-HCl mixtures. These coefficients are 6.45±0.95 x 10⁻¹¹ cm³ s⁻¹ in Ar-HCl (99:1) and 2. 59±.25 x 10⁻¹⁰cm³ s⁻¹ in Ar-N₂-HCl (35: 64:1), for E/N 10⁻²⁰V.m². From these measurements, and from the use of a numerical solution of the Boltzmann equation for electrons, we have calibrated the relative electron dissociative-attachment cross-section measured by Abouaf and Teillet-Billy. The peak values that give the best fit to our data are 9.4 x 10⁻¹⁹ cm² for Ar-HCl and 18.0 x 10⁻¹⁹ cm² for Ar-N₂-HCl.

abstract: Master of Science (MS)


title: The Sulphidation Properties of Fe-10wt% Al Alloys at 1173 K in H₂S/H₂ Atmospheres

contributor:
Smeltzer, W.W.
Purdy, G.R.
Mechanical Engineering

abstract:
The sulphidation properties of Fe-10wt% Al alloys at 1173 K in H₂SH₂ atmospheres were studied in the range of PS₂ = 1 x 10⁻² atm to 1 x 10⁻⁶ atm with special reference to the morphological development in the sulphide scale. Nodular growth of Fe₁₋ᵪS has been observed at Ps₂ = 1 x 10⁻⁴ atm to 1 x 10⁻³ atm with extensive internal sulphidation beneath these nodules.

Sulphidation kinetics of the Fe-10wt% Al alloys were approximated to a two-stage parabolic rate. Aduplex scale is observed with an outer layer of Fe₁₋ᵪS, an inner layer composed of Fe₁₋ᵪS + FeAl₂S₄ having a pearlitic appearance and Al₂S₃ platelets or needles at the alloy/scale interface. At long exposure, a film of FeAl₂S₄ + Al₂S₃ develops at the alloy/scale interface. Two models are advanced for the growth of this film. The presence of Al₂S₃ platelets or needles beneath the continuous Al₂S₃ film is interpreted to result from morphological breakdown of the Al₂S₃ alloy interface and internal sulphidation. Platinum markers were found between the outer and inner layers suggesting growth of the outer layer by outward iron migration and growth of the inner layer by inward sulphur migration.

A schematic ternary Fe-Al-S isotherm is constructed using the alloy sulphidation results and available thermodynamic data with respect to the binary sulphide phases. Various virtual diffusion paths representative of the sulphidation kinetics and scale microstructures for Fe-10wt% Al and Fe-15wt% Al alloys are indicated on this schematic diagram.

abstract: Master of Engineering (ME)


title: Heidegger on Plato's Cave Alethology

contributor:
Madison, G. B.
Philosophy

subject: Philosophy Philosophy

abstract:
In Plato's Doctrine of the Truth (PLW), Martin Heidegger argues that Plato, in the Republic, yokes truth to a preconceived notion of logical and moral rightness. This yoke is a result, Heidegger argues, of Plato's basic orientation towards beings. For Plato the essential characteristic of beings, so runs the argument in PLW, lies in the [symbol removed], a being's whatness, its essential nature. Heidegger maintains that Plato is wrong in so characterizing beings, since unhiddeness [symbol removed] and not whatness is the primordial characteristic (Grundzug) of beings. Heidegger further argues that Plato holds a Correspondence Theory of Truth, that for Plato [symbol removed] is really [symbol removed] (rightness), and that [symbol removed] is the correspondence [symbol removed] of the correct [symbol removed] to the right [symbol removed].

In PLW we find Heidegger in the midst of a contemporary philosophical debate, more or less on the side of those who expound, in multifarious ways, the existentialist's l'existence précède l'essence, while opposing the so-called Platonic-Scholastic Essentia antecedit Existentiam. My purpose in this thesis is twofold: first I show how Heidegger's thesis in PLW is based on his alethology in Being and Time (SZ), and secondly I show how Heidegger, by neglecting the role that to agathon plays as the originating locus [symbol removed] of aletheia, misconstrues the notion of truth put forth in the Republic.

abstract: Master of Arts (MA)


title: Problem-oriented training promotes spontaneous analogical transfer

contributor:
Begg, Ian M.
Psychology

subject: Psychology Psychology

abstract: Analogical transfer is using information from one problem to help solve a subsequent problem to which it is equally as applicable. This transfer is called "spontaneous" if it occurs without any hint being given to the solver that the information from the earlier problem (the training analogue) will help solve the current problem (the target problem). The research literature shows that although subjects can use information from a training problem to help solve a target problem when explicitly instructed to use the information, they do not often do it spontaneously. In this thesis, thirteen experiments work together to demonstrate that problem-oriented processing of the training information leads to significant levels of spontaneous analogical transfer. Experiments 1, 2a, and 2b show that when subjects attempt to solve training problems, fail in their attempt, and then are provided with the appropriate solution and explanation, transfer of the training problem's principle to the target is likely, resulting in high solution rates on target problems. Whether or not the scenario of the training problem is the same as that of the target problem makes little difference so long as the principles are the same. In Experiments 3 through 8, and 11 and 12, it is shown that if subjects try to solve a training problem before hearing its solution, or try to explain a training problem's solution before hearing the correct explanation, spontaneous analogical transfer is much more likely than if subjects study the training problem for memory before hearing its solution or explanation. The advantage of problem-oriented training over memory-oriented training prevails despite the fact that the solution and explanation attempts nearly always fail, and the advantage is just as robust if the target problem is tested approximately 16 minutes after training rather than immediately thereafter. In Experiments 9 and 10, the extent of the benefit when the explanation does not follow the attempt to explain is examined. In Experiment 9, when the experimenter-provided explanation is replaced with verbatim repetition of the story, the benefit decreases a little. In Experiment 10, when the subjects are asked to recall the training story rather than listen to the experimenter-provided explanation, the benefit is eliminated. Problem-oriented training is superior to memory-oriented training when subjects are tested on problem transfer, but when the test is a memory test, memory-oriented training is superior to problem-oriented training. I conclude that problem solvers can spontaneously transfer information from analogous problems if they try to solve or explain the earlier problems and receive the appropriate solution or explanation feedback. The reason for the effect is that problem-oriented processes performed at study are the appropriate processes to use at test.

abstract: Doctor of Philosophy (PhD)


title: In Praise of Hedgehogs: Alfred North Whitehead's Critique of Hume

contributor:
Najm, S. M.
Philosophy

subject: Philosophy Philosophy

abstract: This essay presents a particular perspective into Alfred North Whitehead's critique of David Hume's philosophy of experience. The first section sets forth the problem which Whitehead saw in Hume's philosophy: the problem that were one to consistently hold Hume's position one would be reduced to what George Santayana calls the 'solipsism of the present moment.' The section section concerns Whitehead's understanding of the cause of Hume's problem, abstraction. Section three considers Hume's particular brand of abstraction, sensationalism, and its relation to visual experience. Section four deals with the rudiments of the Whiteheadian solution of Hume's problem. A brief conclusion attempts to put Whitehead's critique into perspective and suggest further inquiries.

abstract: Master of Arts (MA)


title: Rb-Sr Geochronology and Sr Isotope Systematics of Some Major Lithologies in Chandos Township, Ontario

contributor:
Shaw, D.M.
McNutt, R. H.
Geology

subject: Geology Geology

abstract:
The strontium isotopic composition of three major units in Chandos Township was investigated to determine the age of each unit and attempt to discern some geological enigmas associated with these rocks.

The Loon Lake pluton is composed of a monzonite core gradational to a quartz monzonite rim with subordinate isolated outcrops of diorite-gabbro and granodiorite gneiss. Separate Rb-Sr whole rock isochrons were determined for the monzonite (t=1052±21 Ma.; Ri=0.7036±6) and quartz monzonite (t=1071±17 Ma.; Ri=0.7034±5). Since these ages and initial strontium ratios (Ri) are indistinguishable, the data from both units were combined to form a Loon Lake composite isochron (t=1065±13 Ma.; Ri=0.7034±4). The age determined from the composite isochron is interpreted as the time of emplacement of this pluton. The overlap in Ri favours a cogenetic relationship for these two units dominated by fractional crystallization but the extreme Rb enrichment in the quartz monzonites and the significant hiatus in the average o18Owr values (monzonite - 9.5 ‰; quartz monzonite - 11.0 ‰) are difficult to explain by this model. The relatively high range of δ¹⁸Owr values for this pluton (8.8 to 12.0 ‰) and the low Ri reflect a source in the lower crust.

The Tallan Lake sill consists of an upper 180 meters of amphibolite which is transitional to a lower 80 meters of well foliated syenite. Strontium isotope results for samples from both horizons were combined in the regression treatment to yield a McIntyre III errorchron age of 1225±50 Ma. Although there is some uncertainty associated with this errorchron age, this data is interpreted to indicate the time of intrusion of the sill. This data is consistent with the contention that these rocks represent a consanguineous sequence which now forms part of a large scale nappe structure. A mantle derivation for this sill is supported by the low Ri (0.7031±7).

A detailed strontium isotope study of the Apsley biotite gneiss indicated contrasting systematics between the "sodic" and "potassic" suites. The results from a regression treatment of five "sodic" Apsley gneiss samples indicated an isochron age of 1402±57 Ma. This age is interpreted as an average depositional age for the volcanic and sedimentary components of this unit thus the Apsley gneiss represents the oldest known rocks in this part of the Grenville Province. The low Ri for the sodic samples (0.7022±12) provides additional evidence that the isotopic composition of this unit was not severely affected by Grenville metamorphism. On the other hand, the "potassic" Apsley gneiss shows open system behaviour.

abstract: Doctor of Philosophy (PhD)


title: The 0.230 Millisecond Isomer in ¹⁴⁶Eu

contributor:
Summers-Gill, R.G.
Physics

subject: Physics Physics

abstract: The levels associated with the decay of the 0.230 ms isomer in ¹⁴⁶Eu were populated by the (⁷Li,3n) reaction on ¹⁴²Nd using a 33 Mev beam of ⁷Li ions. A decay scheme has been proposed for this isomer based on the study of the in-beam and pulsed beam conversion electron, and gamma ray singles spectra. The assignment of spins and parities was based on the multipolarities of the 274.9, 293.9, 358.2 and 377.0 keY transitions determined by conversion coefficient measurements, and the assumed 9⁺ identity of the isomeric state.

abstract: Doctor of Philosophy (PhD)


title: Coincidence Counting Techniques For The Determination of ²²⁶Ra Concentrations in Water

contributor:
Prestwich, W. V.
Physics

subject: Physics Physics

abstract: Three coincidence counting techniques for the assay of ²²⁶Ra in water samples are evaluated and compared. The techniques are based on the detection of alpha-gamma, beta-gamma, and gamma-gamma coincident radiations. Samples were prepared by co-precipitating ²²⁶Ra with barium sulphate. Details of this chemical procedure are presented in this thesis. The lower limit of detection, sensitivity to sample thickness, and system precision are investigated. Finally, two data analysis techniques, the method of Least Squares and the method of Maximum Likelihood, for determining -ray peak areas as applied to low counting rates, are discussed.

abstract: Doctor of Philosophy (PhD)


title: Boundary electron and beta dosimetry-quantification of the effects of dissimilar media on absorbed dose

subject: Physics Physics

abstract: This work quantifies the changes effected in electron absorbed dose to a soft-tissue equivalent medium when part of this medium is replaced by a material that is not soft-tissue equivalent. That is, heterogeneous dosimetry is addressed. Radionuclides which emit beta particles are the electron sources of primary interest. They are used in brachytherapy and in nuclear medicine: for example, beta-ray applicators made with strontium-90 are employed in certain ophthalmic treatments and iodine-131 is used to test thyroid function. More recent medical procedures under development and which involve beta radionuclides include radioimmunotherapy and radiation synovectomy; the first is a cancer modality and the second deals with the treatment of rheumatoid arthritis. In addition, the possibility of skin surface contamination exists whenever there is handling of radioactive material. Determination of absorbed doses in the examples of the preceding paragraph requires considering boundaries of interfaces. Whilst the Monte Carlo method can be applied to boundary calculations, for routine work such as in clinical situations, or in other circumstances where doses need to be determined quickly, analytical dosimetry would be invaluable. Unfortunately, few analytical methods for boundary beta dosimetry exist. Furthermore, the accuracy of results from both Monte Carlo and analytical methods has to be assessed. Although restricted to one radionuclide, phosphorus-32, the experimental data obtained in this work serve several purposes, one of which is to provide standards against which calculated results can be tested. The experimental data also contribute to the relatively sparse set of published boundary dosimetry data. At the same time, they may be useful in developing analytical boundary dosimetry methodology. The first application of the experimental data is demonstrated. Results from two Monte Carlo codes and two analytical methods, which were developed elsewhere, are compared with experimental data. Monte Carlo results compare satisfactory with experimental results for the boundaries considered. The agreement with experimental results for air interfaces is of particular interest because of discrepancies reported previously by another investigator who used data obtained from a different experimental technique. Results from one of the analytical methods differ significantly from the experimental data obtained here. The second analytical method provided data which approximate experimental results to within 30%. This is encouraging but it remains to be determined whether this method performs equally well for other source energies.

abstract: Doctor of Philosophy (PhD)


title: The Magnetic Properties of α and β-Li₂Eu₅O₈ and Neutron Diffraction of VTa₂O₆

contributor:
Greedan, J.E.
Chemistry

subject: Chemistry Chemistry

abstract:
The magnetic susceptibilities of α and β-Li₂Eu₅O₈ powders have been measured. These compounds have ferromagnetic interactions within a chain of Eu²⁺ ions and antiferromagnetic interactions between the chains. The interactions between the chains are very weak and both compounds can be considered to be nearly ideal examples of one dimensional ferromagnets.

No three-dimensional ordering was observed in VTa₂O₆ down to a temperature of 10K, contrary to the observation of TN = 24K by Bernier (6). The critical temperature which Bernier observed was probably due to a two-dImensional ordering.

The atomic parameters for VTa₂O₆ calculated from the powder neutron data, compare well with the atomic parameters of other trirutiles.

abstract: Doctor of Philosophy (PhD)


title: Mechanisms of Electroacupuncture Analgesia as Related to Endorphins and Monoamines: An Intricate System is Proposed

contributor:
Axelrad, A.A.
Atwood, H.L.
Friend, W.G.
Zoology

subject: Zoology Zoology

abstract: It has been hypothesized (Cheng, M.Sc. thesis, 1977) that electroacupuncture analgesia (EAA) is mediated by endorphins, he endogenous morphina-like peptides. According to this previous hypothesis electroacupuncture (EA) stimulates the periaqueductal gray (PAG in the midbrain) to release enkephalins which will activate the raphe-DLF (dorsolateral faciculus) descending inhibitory system to block the pain messages (nociception) at the spinal cord level. In parallel, EA may stimulate the pituitary to release endorphins to produce analgesia. To further explore this hypothesis, several investigations were carried out on the mechanisms of EAA as related to endorphins and the monoamines (serotonin, dopamine and norepinephrine). EA experiments were carried out on B6AF1/J mice which were put in paper receptacles. Noxious responses to radiant heat were measured by the latencies to squeak. EA was applied by inserting stainless steel needles into the acupuncture point, HoKu (the first dorsal interosseus muscles). Drug injections (intraperitoneally) were done in a blind manner. Results suggest that EAA is mediated by stereospecific opiate receptors; the chief component may be the Type I opiate receptors (the latter are located mainly in the analgesic areas in the central nervous system and may be responsible for opiate analgesia). Evidence also demonstrated that EAA may involve pituitary endorphins and ACTH which are usually released together. Dexamethasone, a cortisone dertivative, suppressed EAA probably by a negative feedback inhibition of pituitary release. Two percent saline, which depresses pituitary endorphins also reduced the effectiveness of EAA. The ACTH released by EA causes elevated cortisol levels and a study shows that EA increases blood cortisol levels in horses. Several experiments (including one in this thesis) suggest that the D-amino acids (DAA), D-phenylalanine and D-leucine, produce analgesia by protecting endorphins from enzymatic degradation. The combined treatments with EA and DAA produced a higher analgesia in mice than either treatment alone. This suggests that EA may release endorphin which are protected by DAA, and hence, EA plus DAA together produce a higher analgesia. The present study also shows that EAA does not show cross-tolerance with morphine and that EA reduces signs of withdrawal in the morphine addicted mouse. In another experiment it was found that low frequency (4 Hz) EAA may be mediated by serotonin. Further EA experiments show that dopamine and norepinephrine modifying drugs do not give coherent results while those with serotonin manipulations are very consistent. By combining the results in this thesis with those in the literature I propose an intricate system for the mechanisms of EAA (Figure A). EA at 4 Hz may stimulate teh sensory afferent nerves to several brain regions. In the midbrain PAG, these stimuli release enkephalins which activate the raphe nuclei to send descending inhibition along the DLF to the spinal cord and block incoming pain messages. The DLF-descending inhibitory system may be partly mediated by the neurotransmitter, serotonin. In parallel, EA (4 Hz) may stimulate the beta-endorphin neurons in the hypothalamus and pituitary. The pituitary endorphins may be released into the blood circulation, or may backflow directly into the CSF (the endorphins in the circulation have to pass through the blood-brain barrier to bind to the opiate receptors in the brain for analgesia). If the acupuncture points and the painful areas are in the same segmental levels, EA (4 Hz) may also directly stimulate the release of endorphins in the spinal cord. High frequency (200 Hz) EAA may activate sensory nerves which directly stimulate the DLF-descending serotonin inhibitory systems, thus by-passing the PAG-endorphin systems. In summary, low frequency (4 Hz) EA may stimulate the release of endorphins in the spinal cord, midbrain, hypothalamus and pituitary for pain-relief, while high frequency (200 Hz) EA may directly stimulate the DLF-serotonin inhibitory systems, thus avoiding the endorphin links.

abstract: Doctor of Philosophy (PhD)


title: MECHANISTIC AND SYNTHETIC ASPECTS OF RADICAL CHEMISTRY OF α-AZOCARBINOLS

contributor:
Warkentin, J.
Chemistry

subject: Chemistry Chemistry

abstract:
α-Phenylazodimethylcarbinol, a new compound in the series of α-azocarbinols prepared in our laboratory, was synthesized by air oxidation of acetone phenylhydrazone to give the hydroperoxide which is subsequently reduced to the α-azocarbinol by the action of triphenylphosphine. The kinetics of thermolysis of this new compound, along with those of α-phenylazodiphenylcarbinol, α-azoethers, and α-azoacetates, were studied under several reaction conditions in an attempt to further elucidate the decomposition mechanism of these new azo compounds.

Radical intermediates are involved in the chemistry of these α-azocarbinols. The evidence presented reinforces the claim that α-azocarbinols decompose by an induced radical chain mechanism. Such a radical chain process permits the application of these α-azocarbinols, which generate a variety of radicals R (R is phenyl in this research), to the hydroalkylation (hydrophenylation) of several unsaturated compounds.

abstract: Doctor of Philosophy (PhD)


title: PROBLEMS IN ROLE NEGOTIATION AND DECISION-MAKING IN A PSYCHIATRIC TEAM

contributor:
Holland, J.
Fullan, M.
Maidman, F.
Educational Theory

subject: Education Education

abstract: The thesis is a study of two psychiatric teams, one adult, the other adolescent, working in an out-patient facility in the same psychiatric hospital. The teams are analyzed with respect to their decision-making ability and the extent to which their functioning is a reflection of the hospital system. The two research questions posed are directed at team interaction and team-hospital relations. The research questions are: 1) How do role negotiations effect team decision-making? 2) Is team functioning a reflection of the hospital system? In regard to question (1), the literature supports the view that the main task of an interdisciplinary team is to make negotiated rather than unilateral decisions. Decisions should reflect the inputs from all members of the team. The psychiatric teams, being interdisciplinary, should negotiate to develop alternatives based on guiding criteria from all disciplines. A team decision involves choosing the best alternative presented in the context of an appropriate therapeutic or administrative goal. In respect to question (2), it will be argued that, since the teams are sub-systems of the larger hospital system, they are in a dependent relationship to it. As such, they tend to reflect to a large extent its main characteristics, especially with regard to modes of decision-making. That is, if the hospital makes unilateral decisions, the teams will reflect this tendency. In the examination of both questions, the sociological perspectives of symbolic interaction and general systems theory are employed as they seem to provide a reasonable framework for analyzing the data. To gather the data, tape recordings of consecutive team meetings and interviews with members of both teams were made in conjunction with documentary analysis. The ability to make team decisions involves some understanding of the negotiation process and it appears from the study that members lack such skills. It is also evident that the closed hospital system undermines the climate for negotiations. Consequently, it would not be sufficient to merely develop team decision-making skills without at the same time changing the present closed hospital system to accommodate a more open team system. Initially, to bring about desired changes on the teams, an in-service training program is required which would not only increase cognitive skills for team decision-making, but would also motivate members to use these skills once they are acquired. To lend some support to the proposed changes on team functioning, the hospital system of which the team is a part should also be changed, given the reciprocal nature of their relationship. A less rigid and authoritarian hospital organizational structure might help to encourage the maturation of a more open team system where members would negotiate to reach team decisions. Out of this kind of inter-disciplinary decision-making might evolve a non-medical model of therapeutic intervention which assumes that adequate mental health services can be provided by all the mental health professional including the psychiatrist, all working together as equals. In making recommendations for change it is helpful if the change agent appreciates that both systems, the team and the hospital must be encouraged to change together since they are in a reciprocal relationship. So, in the implementation of any meaningful innovation he would need the active participation of team members as well as those in the hospital hierarchy. Also, since sudden changes would probably be resisted perhaps at all levels of the organization, the change agent would have to be satisfied with facilitating incremental change or step by step implementation and in this way insure gradual incorporation of the proposed changes into both systems.

abstract: Doctor of Philosophy (PhD)


title: THE EFFECT OF CERTAIN PARAMETERS ON THE SEPARATION OF VARIOUS LIQUID/LIQUID SYSTEMS BY A HYDROCYCLONE

contributor:
Woods, D. R.
Civil Engineering

subject:
Civil Engineering
Civil Engineering

abstract:
A 2 inch diameter, conical-shaped glass hydrocyclone, operating without an air core, was used in this study. The geometric dimensions of the cyclone followed closely with the optimum design conditions determined for solid/liquid systems by Rietema (R-1) and used by Burrill and Woods (B-3) for liquid/liquid systems. Distilled water was used as the continuous phase. Dispersed oil phases studied include: butanol, methyl isobutyl ketone (MIBK) , toluene and kerosene.

For each of the liquid/liquid systems, the efficiency of separation was determined as a function of volume split, oil/water phase ratio and feed flowrate. Differentiation of the liquid/liquid systems, in terms of physical properties, was based primarily on interfacial tension. Density difference and viscosity of the dispersed phase, were comparable from one system to another. Mixing energy used to disperse the oil phase in the water phase, geometric dimensions and temperature were constant throughout the work. The range of the operating variables were as follows:

i) oil/water phase ratio 0.160 to 1.00

ii) feed flowrate 100 to 365 mL/s

iii) interfacial tension 2.0 to 30.0 mN/m

iv) volume split 0.17 to 3.90

For each system studied, photographs were taken at the inlet and outlets leading to and from the cyclone, respectively, to determine the drop size of the dispersed phase.

The second part of the present work considered the influence that the mixing energy had on the effects of oil/water ratio and feed flowrate as studied in the first part.

The efficiency of separation (Es ) is defined as follows:

[equation removed]

where Y and Q represent volume fraction of light phase and flowrate, respectively, while the subscripts denote specific orifice location on the hydrocyclone.

From the first part the efficiency of separation in the cyclone was a very important function of volume split. The effect of the feed flowrate on separation in the cyclone was dependent on the interfacial tension. The effect of oil/water ratio was dependent on the rate of coalescence. Based on the photographic work, coalescence occurred in the cyclone for several of the systems studied.

The majority of past work has varied the mixing energy with a change in the feed flowrate. As a result, drop size varied. Present work revealed that this reversed the effect that feed flowrate had on the separation in the cyclone with mixing energy constant.

It was not possible to obtain two pure phases from the hydrocyclone for any of the systems studied. One pure phase, however, was achieved for three of the four systems studied. A relatively pure water phase (≥ 99%) was obtained at the underflow for the MIBK/water, toluene/water and kerosene/ water systems. The highest values of the optimum Es were 67, 57 and 62%, respectively, for each of these systems. For toluene/water and kerosene/water systems, the interfacial tension was sufficiently high to prevent significant drop breakup when the feed flowrate was increased. Under similar circumstances, drop breakup predominated for MIBK/water and butanol/water systems due to the lower values of interfacial tension. With butanol/water, a significant amount of light phase was found in the underflow. The optimum Es for this system was only 26%.

It was noted that the efficiency of separation, Es, increased sharply at first and then decreased gradually with increasing volume split. The optimum volume split occurred at a value greater than the feed phase ratio for all systems studied. The optimum volume split occurred at a value ranged from 100 to 500% greater than the feed phase ratio. Since complete coalescence does not occur inside the cyclone, it is not possible to have the optimum split equivalent to the feed phase ratio. Continuous phase trapped in the interstides results in the optimum split equivalent to a value greater than the feed phase ratio. A simple mass balance model was used to describe the effects of volume split. From this model the interstitial volume could be inferred for all conditions. Combining this information with models for breakup, coalescence and hindered setting yielded a semi-quantitative explanation of all the trends observed.

The feasibility of using the hydrocyclone to separate emulsions is based on achieving at least one pure phase. If this achievement is accomplished, then it is possible to reduce the volume requirement of a gravity settler. The role of the hydrocyclone is basically one of a preliminary stage in the physical separation process. If, on the other hand, it is not possible to have one pure phase, no useful purpose is served by the cyclone. Consequently, the butanol/water system can not be considered a feasible system to be separated by a hydrocyclone.

abstract: Master of Engineering (ME)


title: Thermodynamics of the Interstitial Phases of Niobium in Iron Austenite

contributor:
Kirkaldy, J.S.
Metallurgical Engineering

subject: Metallurgy Metallurgy

abstract:
The austenite-niobium carbonitride equilibrium has been accurately characterized between 1000°C and 1250°C for commercial steel compositions. A closed capsule technique using hydrogen as carrier gas has been employed to equilibrate Fe-Nb alloys with Fe-C alloys and determine the Υ/Υ+NbCx phase boundary in the temperature range 1000-1250°C. The results have been used to define the solubility of niobium carbide in austenite with improved accuracy. Solubility limits have also been determined by chemical analysis of carbides extracted from a laboratory melted steel. A defect carbide NbC₀.₉ and a carbonitride NbC₀.₉₁N₀.₀₄ have been identified as the equilibrium precipitate compositions at 1000°C in two steels.

To test the data for thermodynamic consistency detailed analysis of the thermochemical data of the defect carbides of niobium has been made. The thermodynamics of the binary Fe-C, Fe-Nb and Nb-C systems have been utilized to determine the Υ/Υ+NbCx equilibrium over relevant composition and temperature ranges and this is in good agreement with the experiments. Solubility product relations are given for the carbide NbC0.87 as this carbide composition has been shown to be a justifiable average equilibrium composition over the temperature range in this study. The carbide solubility relations have been used along with the reported carbonitride solubilities, to estimate the solubility relation for a metastable cubic nitride of composition NbN₀.₈₇.

An accurate method for calculating the composition and solubility of nonstoichiometric carbonitride precipitates in steel has been devised using the above carbide and nitride solubility relations and treating the carbonitrides as compounds with a fixed nonstoichiometry NbCxN(₀.₈₇-x). The effects of Mn, Si, Cr, Ni and Mo on the solubilities of carbonitrides have also been evaluated and it is shown that the carbonitride solubility in a multi-component austenite can be satisfactory predicted. It is therefore possible to calculate, for example, precipitate fractions and theoretical maximum temperatures required in slab reheating to completely dissolve precipitates.

abstract: Master of Engineering (ME)


title: An analysis of phosphotyrosyl-protein phosphatases present in soluble protein extracts prepared from chicken embryo bodies

contributor:
Branton, Philip E.
Medical Sciences

subject:
Medical Sciences
Medical Sciences

abstract: A phosphotyrosyl-protein phosphatase, designated pTPIII, was purified to near homogeneity from soluble extracts prepared from 11-day old chicken embryo bodies. SDS-PAGE analysis suggested that this pTP activity correlated with the presence of a 58 kd protein band in affinity purified enzyme preparations. The purified protein exhibited biochemical characteristics in common with a phosphotyrosyl-protein phosphatase purified from human placental protein extracts, pTP1B (Tonks et al., 1988a; Pallen et al., 1991), and thus may represent the chicken homolog of this protein. Two partial cDNA clones encoding phosphotyrosyl-protein phosphatases were also isolated. Both code for members of the transmembrane class of tyrosine specific protein phosphatases, and thus probably bear no relation to the pTPIII and pTPI activities purified from soluble protein extracts. One cDNA appeared to encode the COOH-terminus of the chicken homolog of LAR, while the second seemed to code for the chicken homolog of PTP-zeta. Two cDNAs encoding PTP-zeta were isolated, however the evidence presented suggested that both clones were likely derived from incompletely processed nuclear RNAs.

abstract: Doctor of Philosophy (PhD)


title: Li Distribution between Chlorite and Albite in a Common Vapor Phase

contributor:
Shaw, Denis M.
Geology

subject: Geology Geology

abstract:
This study attempted to examine the process of Li enrichment in spilites by testing the hypothesis that Li is concentrated in metamorphosed basalts from hydrothermal solutions in the temperature range 400º to 700ºC and at a 1.5 kb pressure. Using a double-capsule technique Li was partitioned between albite and chlorite in a common vapor phase. These minerals were used since they are commonly found in the greenschist facies and chlorite is suspected to be the main Li host. The chlorite (clinochlore) and albite were grown from synthetic gels. A few experiments were also attempted with a natural albite and natural Fe-chlorite. Li analysis was carried out by atomic absorption and neutron activation.

A variation between temperature and the partition coefficient of Li between albite and chlorite could not be resolved. Therefore, the average partition coefficient from all synthetic experiments was D^(alb-chl) = 0.56 ± .06. The partition coefficient in the natural system was not significantly higher, (D^(alb-chl ± 0.81 ± .46). Considerable doubt exists as to the accuracy of the vapor-mineral partition coefficients because of the poor Li mass balance. A range of possible vapor-mineral distributions was obtained:

measured predicted from Li mass balance

D^(vap-alb) 2.77 ± 6.45 5.97 ± 7.99

D^(vap-chl) 1.10 ± 2.31 2.89 ± 3.34

The measured Li partition coefficients do not explain the behavior of Li in spilites because too much Li went into the albite, and the D^(vap-chl) was not less than 1,000 so that most hydrothermal waters do not contain enough Li to produce the observed enrichment in spilites. Lithium may be precipitated in spilites at lower temperatures of pressures than those in this study.

abstract: Master of Science (MS)


title: A Time-Differential Perturbed Angular Correlation Study of K₃HfF₇

contributor:
Prestwich, W.V.
Physics

subject: Physics Physics

abstract:
The method of using time dependent perturbed angular correlations (TDPAC) is used in a study of the hafnium atom's environment in K₃HfF₇. It is found that there are two possible electric field gradients (EFG), different in both magnitude and, asymmetry about the axis of the greatest component, at sample temperatures below 250 ± 1 Kelvin and only one above. This indicates that a solid to solid phase transition occurs at this temperature from a two site structure for the hafnium to a one site form. The EFG asymmetry of the low temperature site, having a relative population of 0.25, increases from 0.62 ± .0.3 to >.95 between 170 and 230 Kelvin. This can be interpreted as the effect of a second state of this hafnium site with an energy difference of approximately 0.25 eV and a relative degeneracy of approximately 10⁻⁷. Such a state could be the result of an impurity or lattice distortion.

Using the K₃HfF₇ as a sample study, the observed data was operated on in a deconvolution analysis to remove the effect of the finite time response of the measurement apparatus. An iterative Bayesian approach was found to amplify high frequency spectral noise less than the linear inverse filter technique however the noise inherent in the measured data limits the usefulness of this type of analysis. The parameters used to describe the EFG interaction, evaluated in a least squares fit of the theoretical expression to the data, were found to be unaffected by the deconvolution operation within statistical uncertainties.

abstract: Doctor of Philosophy (PhD)


title: Far-infrared Absorption by Excitons in Germanium at High Concentrations

contributor:
Timusk, T.
Physics

subject: Physics Physics

abstract:
The dependence on frenuency of the photo-ionization cross~section of indirect excitons in germanium (at concentrations corresponding to "isolated" excitons) was found to be v⁻¹.⁵. A dependence of v⁻².⁷ had been expected, by comparison with the hydrogen theory previously thought applicable. No adequate replacement theory exists. A probable explanation might lie in the Lucovsky model of impurities in semiconductors, which predicts the correct frequency dependence, assuming an enhanced interparticle potential at small separations. This central cell correction was justified in excitons because the dielectric constant of the material varies with the election- hole separation. The - 1.5 power was found to decrease slowly as concentration increased.

The main observation at concentrations of 2x10¹⁴ cm⁻³ and above was a new, strongly absorbing, component of non excitonic character in the absorption spectrum between 1 and 2 meV, peaking at 1.5 meV with a FWHM of ~ 1 meV. The peak grew at the 1.5th power of the exciton peaks, having a fairly sharp onset between 4 and 5.5°K and a very small temperature dependence above that range. This peak was interpreted in terms of an electron-hole plasma analogous to ordinary electron-hole fluid, which appeared in the form of drops in the high density exciton cloud. A double peaked phase diagram was constructed, in qualitative agreement with some theoretical predictions, and experimental results obtained by workers using the recombination luminescence technique, some of whom attribute their results to the formation of biexcitons.

abstract: Master of Science (MS)


title: Effects of Waterborne Zinc on the Blood Acid-Base Status, Blood Gas Tensions, and Plasma Ions and Their Flux Rates, in the Rainbow Trout Salmo gairdneri Richardson

contributor:
Wood, C. M.
Biology

subject: Biology Biology

abstract:
Rainbow trout exposed to lethal (1.5 mg/L) or sublethal (0.8 mg/L) concentrations of waterborne Zn ([Zn]w) exhibited different physiological responses. The lethal response was well-defined, consisting of hypoxemia probably due to gill damage. This in turn caused tissue hypoxia as evidenced by appearance of lactate in the blood, decrease in blood pH, and concomitant changes in related blood parameters. Exposure to lower [Zn]w resulted in changes which were less severe, and varied with water pH, and between artifical and natural soft water. At neutral pH, in artifical soft water (ASW) an alkalosis developed, while at pHw 5, or, in natural soft water at pHw 7, an acidosis occurred similar to acute exposure, but of longer onset. Decrease in arterial oxygen tension (Pa₀₂), where it occurred, was much smaller than in the acute exposure suggesting that damage to branchial epithelial tissue was minimal. Limited lactate appearance in the blood suggested that some hypoxia occurred further along the respiratory chain. The alkalosis was deemed to be a sign of less severe stress arising from altered Cl⁻/HCO⁻₃ exchange.

Exposure to pHw 9 either with or without 1.5 mg/L added Zn was rapidly lethal. Blood pH was normal despite massive accumulations of blood lactate. Un-ionized ammonia concentrations may have been high enough to exert some toxic effect.

Unidirectional branchial flux rates of Na were little altered by exposure to 0.8 mg/L Zn in natural soft water, while Cl⁻ net uptake was reduced t becoming a net loss after 60 h. Net branchial Ca²⁺ uptake was immediately abolished by 0.8 mg/L Zn and showed no subsequent recovery. Reduction in acid excretion at both gill and kidney may have been the cause of the acidosis. Measurements of whole blood and plasma Zn indicated preferential accumulation in the plasma. Possible effects of zinc on carbonic anhydrase and branchial ion exchanges are discussed.

abstract: Doctor of Philosophy (PhD)


title: Photorearrangement of Bicyclo[2.2.1]heptene-2-carbonitrile Observation of 1,2 and 1,3-Sigmatropic Shifts

contributor:
McCullough, J.J.
Chemistry

subject: Chemistry Chemistry

abstract:
The α,β-unsaturated nitrile, bicyclo[2.2.1]heptene-2-carbonitrile, I, was synthesized from norcamphor. Irradiation in hexane with unfiltered light from a medium pressure mercury arc lamp resulted in its conversion to two products, bicyclo[4.1.0]hept-2-ene-1-carbonitrile, II, and tricyclo-[4.1.0.0.³,⁷]heptane-7-carbonitrile, III, in a 20:1 ratio.

[equation removed]

The structure of the major rearrangement product, II, was proven by X-ray crystallography of its crystalline derivative, 1-methylamino-bicyclo-[4.1.0]hept-2-ene-p-bromobenzenesulfonate. The m!nor product, III, was identified by catalytic hydrogenation to 7-cyanobicyclo[2.2.1]heptane and vpc comparison with authentic 7-cyanobicyclo[2.2.1]heptane synthesized from bicyclo-[2.2.1]heptane-7-carboxylic acid.

The photorearrangement of I to II and III are orbital symmetry-allowed photochemical 1,3 and 1,2-sigmatropic shifts, respectively. The 1,3-sigmatropic shift has not been previously observed in the photochemistry of α,β-unsaturated nitriles while the 1,2 shift was observed in the photorearrangement of 1-cyanocyclohexenes. Further experiments are needed to determine whether or not the rearrangements are concerted or diradical in nature.

Preliminary experiments on the related compound, bicyclo[3.2.0]oct-2ene-3-carbonitrile, IV, synthesized from norbornene, indicate that it probably undergoes the same type of rearrangements as I. The ratio for 1,3,to 1,2 a bond shifts seems to be 3:2 in this case.

[figure removed]

abstract: Doctor of Philosophy (PhD)


title: Evaluation of Dissolved Air Flotation for the Treatment of Mineral Slimes

contributor:
Woods, D.W.
Chemical Engineering

subject:
Chemical Engineering
Chemical Engineering

abstract:
The recovery of BaSO₄ mineral slimes (-10 microns) from silica using dispersed and dissolved air flotation, was studied. Experiments were performed in a modified commercial batch flotation machine. The influence of flotation variables such as collector concentration, concentration of silica depressant, pH, aeration and mineral purity on flotation parameters were also examined.

Experimental evidence suggests that dissolved air flotation results in enhanced BaSO₄ recovery over that normally achieved using dispersed air flotation for a limited range of experimental conditions. This range is characterized by poor BaSO₄ flotation conditions such as low pH or collector concentration. The flotation of BaSO₄ was found to be strongly influenced by variables which regulate the surface chemistry of the mineral, such as collector concentration, pH, silica depressant and mineral purity. It was also speculated that mechanical transfer or gangue into the froth may be a critical factor in the upgrading of barite ores.

abstract: Master of Engineering (ME)


title: THE EFFECT OF RESTORATION ON C0₂ EXCHANGE IN A CUTOVER PEATLAND

contributor:
Waddington, J.M.
Geography

subject: Geography Geography

abstract:
Natural peatlands are important components in the global carbon cycle as they represent a net long-term sink of atmospheric carbon dioxide (C0₂), however, peatland extraction converts these ecosystems to persistent sources of atmospheric C02 following abandonment. Peatland restoration techniques have been developed with the aim to restore cutover peatlands to carbon-accumulating ecosystem. This is accomplished by raising the water table and reintroducing Sphagnum peat-forming species. The goal of this thesis was to examine effect of restoration on peatland-atmosphere C0₂ exchange at a cutover peatland.

Peat respiration decreased in the restored site post-restoration, which was partially due to the rewetting. However, the seasonal average peat respiration from both the restored and cut over sites were not significantly different from each other. Subsequently, rates of gross ecosystem production have increased over the same period due to the emerging vegetative cover, with seasonal mean net ecosystem exchange fluxes for both herbaceous and moss vegetation displaying significant improved net C0₂ fixation with time post restoration. Light response curves showing the relationship between gross ecosystem production of C0₂ (GEP) and photosynthetically active radiation (PAR) indicate that both the apparent quantum efficiency and the maximum GEP (Amax) increased with time post-restoration.

abstract: Master of Science (MS)


title: Design of Microwave Printed Circuit Log - Periodic Antennas

contributor:
Campbell, C.K.
Electrical Engineering

subject:
Electrical and Electronics
Electrical and Electronics

abstract:
The subject presented in this thesis concerns the design and fabrication of microwave printed circuit log - periodic antennas meant for operation at frequencies above 1.0 GHz. The designs has its basis in the work which was presented by Robert L. Carrel as a Ph. D thesis in 1961 and is one of the classic papers in the design of log - periodic dipole arrays.

The method is modified to some extent firstly to compensate for planar, instead of cylindrical dipole and the effect of the dielectric loading which the supporting substrate provides.

Methods which allow feeding the array from the opposite direction in which the main lobe extends are also discussed, one of which, the mode converter, is found to be immediately successful.

A typical antenna is fabricated, its input impedance and radiation pattern measured and the results discussed with some comparison to Carrel's results.

abstract: Master of Engineering (ME)


title: CELTIC AND IRISH MYTH AND FOLKLORE IN THE FICTION OF JAMES JOYCE AND MORGAN LLYWELYN: THE PHYSICAL HERO, THE DEVOURING FEMALE, AND MYTH-MAKING

contributor:
Granofsky, Ronald
English

subject:
Arts and Humanities
English Language and Literature
Arts and Humanities

abstract: There is a substantial amount of academic criticismon James Joyce, of which only a small percentage is on the influence of Irish myth and folklore. The clear allusions to Greek myth in Ulysses and in A Portrait of the Artist as a Young Man through the character Stephen Dedalus (and perhaps the popular knowledge of Greek myth) tend to overshadow Joyce's allusions to Irish myth. In a comparison of Joyce to Irish author Morgan Llywelyn, I examine the ancient Irish hero Finn Mac Cumhail, the "Devouring Female," and the value, process, and effects of making myths and folklore. Although there has not been any academic criticism on Morgan Llywelyn ,I believe that the value of her novels will soon be discovered, particularly their worth as rewritings of ancient Irish myth and folklore. My primary texts are Joyce's Ulysses, A Portrait of the Artist as a Young Man, and Dubliners, as well as Llywelyn's Finn Mac Cool.

abstract: Master of Arts (MA)


title: CONTROL PERFORMANCE EVALUATION AND DIAGNOSIS

contributor:
Marlin, T.E.
MacGregor, J.F.
Chemical Engineering

subject:
Chemical Engineering
Engineering
Chemical Engineering

abstract:
A working definition of "good" control performance was considered and the criteria for its measurement were then determined. This study is focused on a time series approach to control performance evaluation and diagnosis, in which statistical tools such as the auto correlation and cross correlation functions and the power spectrum, as well as the input and output variances are used. This technique allows the use of normal operating data for control system performance evaluation, thus requiring minimal effort.

Several simulation and industrial cases were investigated for this research, including SISO feedback and feedforward-feedback strategies as well as MIMO applications. The basis of this approach is the comparison of the existing controller statistical properties to that of a theoretical optimum. In this manner, it is possible to ascertain whether the potential for controller improvement exists and is warranted. The diagnostic procedure then allows for the determination of the likely cause of inadequate control performance, with the ability to distinguish between poor tuning and model mismatch and between poor feedforward or feedback control or the specific controlled or manipulated variable in a MIMO system.

abstract: Master of Engineering (ME)


title: INCREASING CALCIUM INTAKE IN YOUNG WOMEN THROUGH GAIN-FRAMED, TARGETED MESSAGES

contributor:
Martin Ginis, Kathleen A.
Human Biodynamics

abstract: The purpose of the present study was to test the effects of message framing and targeted messaging on calcium intake behaviour. Young women who were consuming less than adequate amounts of calcium attended a one-hour seminar, received two pamphlets, one sticker, and one notepad in the mail over the course of one year, all containing information about osteoporosis, bone, and how calcium intake relates to each. Using message framing and targeted messaging as the intervention, participants were randomly assigned to receive the standard care seminar and materials (control), or gain-framed targeted seminar and materials (experimental). Examination of the data revealed that the intervention had significant effects on calcium intake behaviour, and minimal effects on the health belief model (HBM) constructs. No relation was found between HBM constructs and calcium intake. Specifically, using an intent-to-treat repeated measures ANOVA, participants in the experimental condition significantly increased their calcium intake more than those in the control condition over the course of the study (p < .01). All HBM constructs changed over time in both conditions (ps < .05) except for perceived severity (p= .89).Self-efficacy was the only construct to improve significantly more in the experimental condition versus control (p < .01). The HBM predicted calcium intake only during week 25 (p < .01). These findings suggest that it is possible to increase young women's calcium intake consumption through gain-framed, targeted messages. Findings also have important implications for how existing osteoporosis-preventive materials can be improved.

abstract: Master of Science (MS)


title: Anime: The Cultural Signification of the Otaku

contributor:
York, Lorraine
English

abstract: Technology has allowed nearly instantaneous communication around the globe and this study examines how cultural transmission occurs through the consumption of television and film. Anime, a term used to refer to a genre of animation that is of Japanese origin, has become immensely popular in North America and has come to simultaneously come to signify a commodifled Japanese youth culture. However, the spectrum of Japanese animation is restricted and controversial anime that includes offensive themes, violent, sexual or illicit material are not televised, or publicized except when associated with negative behaviour. The Otaku are labeled as a socially deviant subculture that is individualistic and amoral. Their struggle for autonomy is represented by their production, circulation and consumption of manga and anime, despite the insistence of the dominant Japanese and North American cultural discourses. This study will examine how publicly circulating definitions, media review, historical relations and censorship have affected the portrayal of otaku subculture in Japan and internationally.

abstract: Master of Arts (MA)


title: BLIND ADAPTIVE MULTIUSER DETECTION OVER TIME-VARYING TIME-DISPERSIVE CHANNELS

contributor:
Kirubarajan, T.
Electrical and Computer Engineering

subject:
Electrical and Computer Engineering
Engineering
Electrical and Computer Engineering

abstract: In this thesis, blind multiuser detection of Direct Sequence Code Division Multiple Access (DS-CDMA) signals over time-varying time-dispersive channels is considered. A number of methods for multiuser detection over time-dispersive channels have been proposed previously. Blind multiuser detection requires that the signature waveform of the desired user be reconstructed (blindly) at the receiver. In time-dispersive channels the knowledge of the channel order (length) is needed in order to reconstruct the signature waveform exactly. Previous works in this regard assumed the knowledge of the channel length or they considered an over estimated channel length. However, when the channel length assumed at the receiver differs from the actual one, the performance of the system can degrade significantly. Hence we propose a new multiple model approach that considers many channel-conditioned multiuser detectors in parallel in order to obtain a better estimate via soft decision, instead of making a hard decision about the channel length. We use the Interacting Multiple Model (IMM) estimator, which consists of multiple Kalman filters, to find a better overall estimate from the channel-conditioned filters. Further, in a time-varying environment, where the channel length varies with time, the proposed scheme tracks the channel order very well (without assuming known channel length), and hence performs better than previous methods. Simulation results show that the proposed method outperforms the existing ones in terms of signal to interference plus noise ratio and bit error rate in a time-varying channel.

abstract: Master of Applied Science (MASc)


title: Rama Township

subject: Geography

abstract: This thesis is a regional study of the physical and human geography of Rama Township. An area of 35,954 acres, it is situated on the east shore of Lake Couchiching. Within the township's boundaries there are two lakes - Lake St. John (pronounced Sin-jun) and Mud Lake. There are also several rivers, the most important being the Black River and its tributary, the Head River. The Severn River marks the north-western limit of the township. Two railways, both Canadian National, traverse the area, converging at Washago. Highway 11 and 12 lead to Rama from large population centres. There are 81 miles of road within the township. Highway #69 is provincial and follows the Couchiching shore. Although gravel, it is kept in fair condition. There is one county road reaching from O'Connell to Fawkham which is also well kept. The remaining are township roads and are not usually in very good condition. Rama Township has a population of 653. Of these, 379 are concentrated along the lakeshore. There is an additional 375 Indian residents. A large summer population, much of which is transient, swells this total during the warmer months. The progress of Rama has been limited to some extent by the environment. In some cases, the people have over come difficulties and made very satisfactory adjustments to adverse conditions. Yet if the people of Rama Township could understand their environment more fully, they would be able to gain a more balanced economy, a more efficient land utilization, and some types of specialization which would provide a surplus for sale outside of the township. If this could be done, the threatening bonds of self-sufficiency would be broken.

abstract: Bachelor of Arts (BA)


title: A Study of Urban School Trustee Decision Making

contributor:
Leithwood, K.
Bargen, P.
Williams, T.
Educational Theory

subject: Education Education

abstract: Education in the seventies is attracting much attention from the media, the general public and the political sector of society. The public school system of Ontario, especially its changes in governance structure in 1969 and accompanying administrative problems, warrant research and interest. The elected trustees that make up school boards complete a structure of local government that is responsible for the education system of a Canadian society. Public education is provided through its representative elected boards of education, appointed professional administrative staff, and practicing professional teachers. Research into the role of trustees in school board decision making is in essence research in educational politics. Within such a political context the question of governance appears relevant at all times. Research in 1974 concluded that the prevalent view among contemporary students of educational politics is well founded: school boards have largely ceased to exercise their representative and policy making functions; for the most part they do not govern, but merely legitimate the policy recommendations of school superintendents. The intent of this study was to determine how trustees of one Canadian urban school board made decisions by identifying and conducting an analysis of the primary factors considered by them as they engage in deciding on specific issues as individual members of a board and as a board of trustees. This study involved an in-depth investigation of a metropolitan urban school board. Its product comprises a description of factors considered by trustees prior to voting on specific board motions or issues. A primary aspect of this study was an assessment of each factor's relative importance in the estimation of each trustee for his/her making of decision. This research also provided insight on several related matters. The first concerns the involvement of school board officials in school trustee decision making. The second involves the relative influence of administrative staff on the one hand, and school trustees on the other, in shaping the decision made by school boards. The third allows for the identification of board decision making variables not extensively heretofore elaborated on.

abstract: Doctor of Philosophy (PhD)


title: Pair-breaking in superconductivity

contributor:
Carbotte, J.P.
Physics

subject: Physics Physics

abstract: We have examined within Eliashberg theory the effect of several pair-breaking mechanisms on superconducting properties. Many predictions are made, some of which have recently been confirmed experimentally. First, we present the strong coupling theory of the thin film critical current. Predictions for the temperature dependence of this property are made for the cases of strong inelastic scattering, spin fluctuations, and magnetic and non-magnetic impurity scattering. We next examine the recently proposed marginal Fermi liquid theory, which has been shown to account for the unusual normal state properties of the high Tc superconductors. Here we have calculated several superconducting properties in this model. The most important result arising from this work is the effect of the gapping of the spectrum of fluctuations. This produces a drop in the quasiparticle damping rate below Tc and a peak in the low frequency temperature dependent conductivity. These predictions have been recently confirmed by several experiments. Also, in the frequency dependent optical conductivity, no absorption is predicted up until 4Δ in the clean limit. The experimental observation of a lack of Holstein structure in the ratio of the superconducting to normal state optical conductivity is explained. Several electromagnetic properties of superconductors are calculated with the inclusion of spin fluctuations and paramagnetic impurities. Predictions are made for the optical conductivity in the clean limit with magnetic impurity scattering. In this latter case, the Holstein structure will be reduced from the pure case and absorption will occur below 2Δ. Finally, we have examined a model for a spin glass superconductor which leads to a temperature dependent scattering rate. Within this model several thermodynamic and electrodynamic properties have been examined, giving results which might be confirmed by experiment. Reentrant behaviour is predicted for a certain choice of parameters.

abstract: Doctor of Philosophy (PhD)


title: Design of a Saw Oscillator at a Harmonic Frequency

abstract:
The use of harmonic mode SAW filters allows the fabrication of UHF oscillators with standard lithographic techniques. However, such devices previously required external filtering to select the desired harmonic. This in turn requires relatively high O circuits with their associated alignment problems and phase sensitivity.

This thesis discusses a technique which permits harmonic operation without the external circuitry. By utilizing the theory of the end-fire array antenna a stepped-delay line has been fabricated at frequencies greater than 400 MHz using the fifth harmonic (i.e. fundamental at 80 MHz). The result is a packaged SAW oscillator which exhibited an output power of -15 dBm into a 50 Ω termination at a harmonic frequency of 404.3 MHz. Short term stability measurements made yield a short term stability of better than 1 part in 10⁹ over a period of 1 sec.

abstract: Master of Engineering (ME)


title: THE SYNTHESIS AND THERMAL DECOMPOSITION OF 5,5-DIPHENYL-2-(ARYLIMINO)-Δ³-1,3,4-OXADIAZOLINES AND 5,5-DIALKYL-Δ³-1,3,4-OXADIAZOLIN-2-ONES

contributor:
Warkentin, J.
Chemistry

subject: Chemistry Chemistry

abstract: The thermal decomposition of 2-(arylimino)-5,5diphenyl-Δ³-1,3,4-oxadiazolines, prepared by the oxidation of benzophenone 4-arylsemicarbazones by lead tetra-acetate, was studied. A possible mechanism of the decomposition is discussed in the light of a correlation between the rate constants and substituent constants. The configuration of N,5,5-trisubstituted-2-imino-Δ³-1,3,4-oxadiazolines was determined. Several new compounds, 5,5-dialkyl-Δ³-1,3,4-oxadiazolin-2-ones, were prepared by hydrolysis of 5,5-dialkyl-2-(methylimino)-Δ³-1,3,4-oxadiazolines. A literature survey of the oxidative cyclization of nitrogen-containing carbonyl derivatives, and of the thermal decomposition of cyclic azo compounds is presented.

abstract: Doctor of Philosophy (PhD)


title: Levels in ⁹⁷Tc , ⁹⁹Tc , ¹⁰¹Tc and ¹⁰¹Ru

contributor:
Johns, M.W.
Physics

subject: Physics Physics

abstract: Levels in ⁹⁷Tc , ⁹⁹Tc , ¹⁰¹Tc and ¹⁰¹Ru have been studied using the electron-capture decay of ⁹⁷Ru and the beta decays of ⁹⁹Mo, ¹⁰¹Mo and ¹⁰¹Tc, respectively. The energies and intensities of the gamma rays involved in these decays were measured with high precision by Ge(Li) detectors. Gamma-gamma coincidence experiments with Ge(Li)-Ge(Li) and Ge(Li)-NaI(Tℓ) spectrometers have been used to establish 9 levels in ⁹⁷Tc, 14 levels in ⁹⁹Tc, 45 levels in ¹⁰¹Tc and 11 levels in ¹⁰¹Ru. The low energy conversion electron spectrum from the decay of ¹⁰¹Mo was investigated with the Chalk River π√2 spectrometer. From these data, energies, spins and parities for states in ⁹⁷Tc , ⁹⁹Tc , ¹⁰¹Tc and ¹⁰¹Ru have been established and interpreted in terms of the shell model.

abstract: Doctor of Philosophy (PhD)


title: Oxochlorides of Rhenium

contributor:
L., C. J.
Chemistry

subject: Chemistry Chemistry

abstract:
The reaction of rhenium pentachloride and rhenium trioxide in the presence and absence of traces of water was investigated with the intent of identifying, isolating and characterizing new oxochlorides of rhenium. Depending on the conditions of reaction, various amounts of ReCl₅, ReO₃, Re₃Cl₉, ReO₂, rhenium metal, ReO₃Cl, ReOCl₄, ReOCl₄.ReO₃Cl, ReOCl₄(OH₂), Re₂O₃Cl₆(ReO₃Cl)₂ and ReOCl₂ were identified among the products. The compounds ReOCl₄(OH₂), ReOCl₂ and Re₂O₃Cl₆(ReO₃Cl)₂ had not been reported previously. They were characterized by a combination of single crystal X-ray diffraction, X-ray powder photography, neutron activation analysis, infrared and Raman spectroscopy and observation of physical and chemical properties. In addition, improved methods of preparation were found.

ReOCl₄(OH₂) consists of molecules of pseudo-octahedrally coordinated rhenium(VI), with the aquo-group (Re-Aq = 2.27(2) Å) trans to the terminal oxo-group (Re=O = 1.63(2) Å). The average Re-Cl bond length is 2.29(1) Å.

The molecules of Re₂O₃Cl₆(ReO₃Cl)₂ are composed of a dimeric Re₂O₃Cl₆ unit with a bridging oxygen atom at the center of symmetry and an Re-O (bridge) distance of 1.847(1) Å. The remaining oxo-group on each rhenium atom is cis to the bridge and is strongly bonded (1.69(2) Å), and the position trans to the terminal oxo-group is filled by a weak bond (2.41(1)Å) to an oxygen atom of a perrhenyl chloride molecule.

The structure of ReOCl₂ could not be solved by single crystal X-ray techniques because of an apparent disorder in the structure, but characterization of this compound was achieved by a combination of analyses and the observed stoichiometry of the reactions

[equations removed]

Although ReOCl₂ is much more reactive than MoOCl₂ and WOCl₂, the physical and chemical properties of these compounds are somewhat similar.

The chemistry of the rhenium-oxygen-chlorine system is discussed and compared to that of technetium, molybdenum and tungsten.

abstract: Doctor of Philosophy (PhD)


title: Energy Levels of ¹¹⁷In and ¹⁷¹Lu

subject: Physics Physics

abstract:
The energy levels of ¹¹⁷In populated in the beta decay of ¹¹⁷Cd and ¹¹⁷mCd have been studied with the aid of Ge(Li) gamma ray detectors singly and in coincidence mode. A decay scheme based on the present results is proposed and speculation is made concerning a possible interpretation of some of the levels as a rotational band based on the 1/2+[431] Nilsson orbital.

The energy levels of ¹⁷¹Lu populated by single particle transfer reactions have been studied using an Enge spectrograph and a number of Nilsson assignments are made. These results have been complemented by a study of the gamma rays and conversion electrons following the reaction ¹⁶⁹Tm(α,2n)Lu, using Ge(Li) detectors and an on line Orange spectrometer. Assignments were made to high spin for rotational bands based on five Nilsson orbitals. In addition some interesting K forbidden interband transitions were observed and discussed in terms of Nilsson model branching ratio predictions.

abstract: Doctor of Philosophy (PhD)


title: The Nuclear Structure of ¹⁵¹Sm

contributor:
Burke, D.G.
Physics

subject: Physics Physics

abstract: An experimental study of the low-lying levels of the nucleus ¹⁵¹sm has been made using the single particle transfer reactions 1) ¹⁵²Sm (d,t)¹⁵¹Sm , 2)¹⁵¹Sm(³He,α)¹⁵¹Sm, 3) ¹⁵⁰Sm (d,p)¹⁵¹Sm , 4) ¹⁵¹Sm (d,p)¹⁵²Sm, 5) ¹⁵¹Sm(d,t)¹⁵⁰Sm and 6) ¹⁵¹Sm(³He,α) ¹⁵⁰Sm. Also,inelastic scattering and Coulomb excitation experiments were performed on targets of ¹⁵¹Sm. The information obtained from these experiments when combined with the results of previous studies of the decay of ¹⁵¹Pm, has allowed definite spin and parity assignments to be made for about 15 levels in ¹⁵¹Sm, and has put limitations on the possible assignments for several others. The level scheme obtained is compared with the predictions of the Nilsson model, including the effects of Coriolis and ΔN=2 mixing.

abstract: Doctor of Philosophy (PhD)


title: N⁶-(Δ²-ISOPENTENYL)ADENOSINE

contributor:
Hall, Ross H.
Biochemistry

subject: Biochemistry Biochemistry

abstract:
N⁶-(Δ²-Isopentenyl)adenosine is a cytokinin, that is, it promotes cell division, growth and differentiation in certain plant tissues. Some aspects of the metabolism and biological effects of i⁶Ado were studied. These studies have contributed to scientific knowledge in several areas: the biological effects of i⁶Ado on animal and plant cells; the metabolism of i⁶Ado by animal cells; and the origin of free cytokinins.

A. The effects of i⁶Ado on a cell line derived from the circulating leucocytes of a patient with chronic myeloid leukaemia, Roswell Park Memorial Institute line 6410, were studied.

(i) The growth of 6410 cells was not stimulated by i⁶Ado, but concentrations of i⁶Ado of 3 μM inhibited the growth of this cell line. N⁶-(Δ²-Isopentenyl)adenosine did not affect the duration of the lag phase of growth of these cells. There was no detectable maturation of these cells as judged by an alteration in alkaline phosphatase activity under these conditions. An increase in lactic dehydrogenase activity in 6410 cells that have been treated lath i⁶Ado is a non-specific effect related to the death of the cells.

(ii) N⁶-(Δ²-Isopentenyl)adenosine is a component of 6410 cell tRNA in quantities approximately equal to those found in other organisms. Neither i⁶Ado nor the corresponding base, i⁶Ade, nor the corresponding 5' monophosphate, i⁶AMP, were found free in the cells or culture medium.

(iii) The tRNA of cells cultured in the presence of i⁶Ado contains a normal complement of Δ²-isopentenYl groups. This indicates that there is no feedback mechanism between free i⁶Ado and the synthesis of i⁶Ado in the tRNA of these cells.

(iv) Because 6410 cells contain i⁶Ado in their tRNA they are exposed to the free nucleoside that is toxic to them during tRNA turnover. However, 6410 cells contain an enzyme that converts i 6Ado to the corresponding base, that is much less toxic to these cells. This is the first time that this mechanism of detoxification has been demonstrated. The finding is of importance in the development of new cytotoxic drugs related to i⁶Ado, because detoxification reactions potentially limit therapeutic value of a drug.

B. The effects of i⁶Ado on a variant strain of tobacco pith tissue were studied. This is the first report of the effects of this naturally occurring cytokinin on tobacco pith callus at a cellular level.

(i) The variant strain did not differentiate to form mature shoots and leaves as does normal tissue when treated with high concentrations i⁶Ado.

(ii) Administration of i⁶Ado to the variant tissue was followed by cell division and a reduction in cell size within 48 hours. After this period the cell size remained constant but the tissue continued to grow.

(iii) There was an increase in the starch content of the tissue for 10 days following the administration of i⁶Ado. After this time the starch levels remained constant. This is different from the rapid fall in starch concentrations after 12 days noted in tobacco pith tissue that forms organs.

(iv) The growth of the variant tissue was stimulated by i⁶Ado. Unlike normal tobacco pith tissue i⁶Ado in high concentrations, 3 μM, 9 μM did not significantly inhibit its growth.

(v) An hypothesis is proposed relating the effects of i⁶Ado energy metabolism, and tissue growth and organogenesis.

C. The biosynthesis of i⁶Ade was studied using a plant pathogen Corynebacterium fascians. Cultures of this bacteria have been reported to contain up to 100 μg/litre of i⁶Ade.

(i) [8-¹⁴C] Adenine and [8-¹⁴C] adenosine but not [2-¹⁴C] mevalonic acid added to cultures of C. fascians were incorporated by the bacteria. Because [2-¹⁴C] mevalonic acid was not incorporated, it could not be used as a specific label for the Δ²-isopentenyl side-chain of i⁶Ado in the tRNA of these bacteria.

(ii) [8-¹⁴C] Adenine was incorporated into free i⁶Ade extracted from cultures of these bacteria. The extent of labelling of i⁶Ade that was extracted when the cultures were labelled with divided doses of [8-¹⁴C] adenine throughout logarithmic growth phase, was the same as the extent of labelling that occurred when the same quantity of radioactivity was administered in one dose in late logarithmic growth phase.

(iii) When cultures of C. fascians that have been labelled with [8-¹⁴C] adenine are extracted by a procedure in which the pH never falls below 7.0, less than one fifth of labelled ¹⁴C-i⁶Ade is extracted compared with the amount extracted from cultures subjected to heating and mild acidification before the extraction procedure.

(iv) The quantity of i⁶Ade present in the cultures was estimated to be approximately 5.0 μg/litre. Heating and acidification increased the quantity of i⁶Ade present to 36 to 40 μg/litre. This increase in i⁶Ade was shown to be due to release of i⁶Ade from C. fascians tRNA by heating and mild acidification.

(v) Bioassay of extracts of C. fascians cultures showed that i⁶Ado is only a minor component of the total cytokinin activity present. Other cytokinin activity corresponded chromatographically to i⁶Ado, zeatin and ribosyl zeatin.

(vi) On this evidence, I propose that all free cytokinins are not derived directly from the corresponding cytokinin hypermodified nucleosides in the tRNA, because C. fascians tRNA has been shown to contain only one cytokinin.

tRNA may act as a store of relatively inactive cytokinins that are converted to more active cytokinins under appropriate physiological circumstances.

This would enable organisms to exert control over cytokinin activity in its tissues even in the event of tride fluctuations in the turnover of tRNA.

Inevitably, work of this nature generates new questions. An important area for future study appears to be the further definition of the metabolism of i⁶Ado. It is probable that metabolites of i⁶Ado could cause many of the effects that have previously been due to the parent compound. In addition, a better understanding of the mechanisms by which i⁶Ado causes growth differentiation and cytotoxicity may assist in the development of new therapeutic agents.

abstract: Doctor of Philosophy (PhD)


title: Proton States of Deformed Nuclei with A = 153 to A = 163

subject: Physics Physics

abstract:
Proton states of ¹⁵³Eu, ¹⁵⁵Eu, ¹⁵⁵Tb, ¹⁵⁷Tb, ¹⁵⁹Tb, ¹⁶¹Tb, and ¹⁶³Ho have been studied using the (α,t) and (³He,d) reactions. Beams of 24 MeV ³He and 25 MeV alpha particles were produced by the McMaster University model FN tandem Van de Graaff accelerator. The reaction products were analyzed with an Enge split-pole magnetic spectrograph and detected with photographic emulsions. Ratios of the cross sections between the (α,t) and (³He,d) reactions were used as an indication of the ℓ-values for the proton transfers, and the spectroscopic factors were extracted using DWBA calculations. Interpretation of the results is made in terms of the Unified Model.

The results of the present work confirm the assignments of the 3/2⁺[411] and 5/2⁺[413] Nilsson orbitals in the terbium isotopes. The I = II/2 members of the 5/2⁻[532] and 7/2⁻[523] orbitals are identified in ¹⁶¹Tb and ¹⁵⁹Tb and their assignments confirmed in ¹⁵⁷Tb and ¹⁵⁵Tb. It is necessary to invoke appreciable Coriolis mixing between these two orbitals in order to describe the observed rotational level spacings and the spectroscopic strengths. The assignment of the 7/2+[404] orbital is confirmed in ¹⁵⁵Tb and ¹⁵⁷Tb and this orbital is identified in ¹⁵⁹Tb and ¹⁶¹Tb. Previous assignments of the 1/2⁺[411] particle state with vibrational admixtures are confirmed in ¹⁵⁷Tb and ¹⁵⁹Tb and the state is identified in ¹⁶¹Tb. The present results support the earlier evidence for the existence of a second fragment of the 1/2⁺[411] orbital in ¹⁵⁹Tb and suggest the presence of a similar state in ¹⁵⁷Tb. The assignment of the the 5/2⁺[402] orbital is made and tentative assignment of the 1/2⁺[411] orbital is considered for each of the terbium isotopes. In ¹⁶³Ho, the assignments of the 7/2⁻[523] and 7/2⁺[404] orbitals are confirmed, and strong evidence for the assignment of the 3/2⁺[411], 1/2⁺[411], 5/2⁺[402] and 1/2⁻[541] orbitals is found. In the europium isotopes, the assignments of the 5/2⁺[413], 3/2⁺[411] and 5/2⁻[532] orbitals are confirmed, and evidence for the assignment of the 7/2⁻[523], 1/2⁺[411], 7/2⁺[404] and 1/2⁻[541] orbitals is considered.

abstract: Doctor of Philosophy (PhD)


title: Automatic Control of Foundry Molding Sand Constituents

contributor:
Newcombe, W. R.
Mechanical Engineering

abstract: Some of the advantages and problems involved in the conversion from manual to automatic control of foundry molding sand constituents are discussed. The principal problem is that a transducer capable of monitoring each additive content is currently not available. The results of a search for an analytical technique suitable for such a transducer are presented. Of the numerous analytical methods reviewed, the multiparameter electrical technique, appeared to be most advantageous at the time that the survey was made. A description of its experimental evaluation is given. While a suitable transducer is not positively identified, guidelines for further work are suggested.

abstract: Master of Engineering (ME)