title: Photochemical and thermal interconversions of protonated phenols and bicyclo(3.1.0)hexenones

contributor:
Childs, R.F.
Biology

subject: Biology Biology

abstract: The work described in this thesis involves a quantitative study of the photoisomerizations of a series of protonated phenols and the reverse, thermally induced ring opening reactions of protonated bicyclo[3.1.0]hexanones. In the first chapter the importance of these reactions is established in terms of their potential use in photochemical latent heat solar energy storage systems. The second and third chapters consist of the results and discussion of this present work. In the first place the protonation of polymethyl and chlorophenols in CF₃SO₃H (room temperature) and FSO₃H (low temperature) have been investigated using ¹H NMR and UV spectroscopy. Apart from 2,3,4,5-tetramethylphenol protonation at C₄ was observed for all methylphenols in CF₃SO₃H. In the case of 2,3,4,5-tetramethylphenol, both C₄ (95%) and C₆ (5%) protonation was observed. With 2-chloro- and 3,5-dichlorophenols 85 and 87 in FSO₃H O- and C₄-protonation was observed. One difference in this work to that previously reported is the use of CF₃SO₃H as a strong acid medium. Overall, the same cations were produced in CF₃SO₃H as in FSO₃H. However, in certain cases there were some differences noted in the ¹H NMR spectra of these ions as compared to those obtained at low temperature in FSO₃H. These differences are discussed in terms of an exchange of the ring protons of some of these protonated phenols with CF₃SO₃H. The photochemical reactions of the C₄ protonated phenols in stong acid media (i.e. CF₃SO₃H and FSO₃H) have been examined. Most of these protonated phenols were found to undergo clean photoisomerizations to give protonated bicyclo[3.1.0] hexanones. Neutralizations of the irradiated acid solutions gave substituted bicyclo[3.1.0]hexanones. The quantum yields for the photoisomerization of a number of protonated phenols to the bicyclo[3.1.0]hexanones were measured in CF₃SO₃H. It was found that substituents have a profound effect upon the efficiency of these reactions. Methyl groups in the two ortho positions were found to increase the efficiency of the reaction, while methyl substituents in the meta position were found to reduce the efficiency dramatically. This substituent effect can be understood in terms of a two step mechanism with the initially formed intermediate undergoes competitive thermal reactions. The relative rate of these two processes would seem to depend on the positioning of the methyl substituents. A quantitative investigation of the ground state isomerizations of a series of methyl substituted bicyclo[3.1.0]hexanones in CF₃SO₃H was also undertaken. In every case the protonated bicyclo[3.1.0]hexanones isomerized to give a protonated phenol. The activation energies for these processes were sufficiently high in several instances to necessitate heating the solutions to 100°C for several hours in order for the reactions to be completed. An analysis of the products of these reactions showed that the ring opening could take place by three different mechanisms. The factors which determines the preferred isomerization route are discussed in the thesis. In the concluding part of the thesis the quantitative results found in this work for the protonated methyl substituted phenol/bicyclo[3.1.0]hexanones interconversion are discussed in terms of their use for solar energy storage.

abstract: Doctor of Philosophy (PhD)


title: Adsorption of simple molecules on graphite: A computer simulation study

contributor:
Klein, Michael L.
Chemistry

subject: Chemistry Chemistry

abstract:
The structure and dynamics of monolayers of the simple hydrocarbon molecules CH₄, C₂H₄ and C₂H₆, physisorbed on graphite, have been explored by computer simulation, along with the behavior of corrugated bilayer systems of the dipolar molecules CH₃F and CH₃Cl on Xe/graphite.

The simulations found that the corrugation of the surface can have a strong effect on the monolayer structures of these molecules. The experimentally observed phases of C₂H₆ and CH₃F were found to be stabilized by the surface corrugation, though C₂H₄ and CH₃Cl were not. The structure of CH₃Cl/Xe/graphite was found to be an array of vertically aligned anti-ferro ordered pairs of molecules arranged in rows on the surface, while CH₃F/Xe/graphite formed zig-zag chains lying flat on the surface.

The dynamics of these layer systems was also examined. In each case, the calculated power spectra agreed well with experiment, and showed strong evidence for translation-rotation coupling in the monolayers. The motions of CH₃F and CH₃Cl were particularly coupled to the motions of the underlying Xe layer.

Simulations of the melting of ethylene suggest a novel mechanism: the molecules create locally enhanced density fluctuations necessary for melting by standing up from the surface, smearing the transition, and making it appear continuous.

Calculated diffusion constants in the liquid phase of methane on graphite agreed well with experiment. Similar calculations of liquid ethylene did not agree as well with experiment, possibly because of an inadequate potential.

abstract: Doctor of Philosophy (PhD)


title: A path integral Monte Carlo study of quantum solutes in liquid ammonia and ammonia clusters

contributor:
Klein, Michael L.
Biology

subject: Biology Biology

abstract:
The path integral Monte Carlo method is applied to some solvation problems involving quantum solutes. Thermodynamics quantities like partial molar volume and entropy change associated with the electron solvaton process are calculate. The ionization of alkali atoms in liquid ammonia and the electron attachment to ammonia clusters are investigated.

Path integral MC simulations at constant pressure lead to an expansion of the simulation box in satisfactorily agreement with the experimental molar volume. The structure of the solvated electron at constant pressure was found to be very similar to the one at constant volume. The electron wavefunction was only slightly expanded.

The Debye charging trick is used to calculate the free energy of the solvated electron at constant volume. The experimental solvation entropy at constant pressure is reproduced only when a correction due to the volume expansion is introduced. The contribution to the entropy due to the ordering of the ammonia molecules induced by the electron is negative. The expansion work, performed by the light when the electron is introduced, is responsible for the positive experimental entropy.

Spontaneous ionization is observed only for Na and Cs when a hard core (HC) pseudopotential is employed. A soft core (SC) pseudopotential leads to the formation of dipolar atoms when tested with Li and Cs. A dipolar Li atom is observed even for the HC model. These calculations predict that the minimum energy state for at least Na and Cs is indeed the separately solvated ions. This is agreement with the experimental evidence.

The nature of electron attachment to ammonia clusters composed of 16, 36, and 54 molecules is studied. At 100 K, a negatively charged clusters of 16 molecules appears to be unstable in the sense that the electron binding energy is less than kBT. For both the 36 and 54 molecule clusters the electron binds to the cluster surface. The 54 molecule cluster also supports a (meta) stable interior solvated state. These findings are discussed in the light of experimental data on the same system.

abstract: Doctor of Philosophy (PhD)


title: Microstructure and transient thermal stress analysis of austenitic stainless steel weldments using finite element method

contributor: Civil Engineering and Engineering Mechanics

subject:
Civil Engineering
Engineering Mechanics
Civil Engineering

abstract:
A micro/macro-structural analysis is undertaken to determine the effects of welding thermal cycles on austenitic stainless steel. The analysis is subdivided into three parts; heat flow analysis, micro-structural analysis, and thermal elastic visco-plastic analysis.

A three-dimensional, finite element program based on heat conduction equation is developed and also incorporates a model for heat input due to welding to approximate the welding thermal cycles. The program is capable of handling the nonlinear material properties according to the temperature field. A two-point recurrence scheme is employed to obtain the temperature field for every time step. A weighted residual iterative method is employed to minimize drifting.

A micro-structural model based on the Avrami Equation and the grain growth law is developed to predict the grain growth due to welding. The heat affected zone is assumed to be composed mainly of the grain growth zone for the austenitic steel and ignores the recrystallization process.

A coupled thermo-elastic viso-plastic formulation including the micro-structural changes is developed to predict the overall deformation and residual stresses caused by a welding thermal cycle. The macro-structural behaviour is modelled by using the nine-node isoparametric shell element. A twenty seven integration point scheme per element is used to transfer the temperature and the thermal strain field from the heat flow analysis and the austenite grain size from the micro-structural analysis to the thermal elastic visco-plastic analysis. An incremental load method is used along with the Newton-Raphson iterative method to solve for the incremental displacement and hence obtain the macro-structural response.

After the development of all segments of the finite element programs, the accuracy and the stability of the solutions are tested. Various studies are conducted to check the modelling of the heat flow for both low carbon steel and austentic stainless steel, and the results are compared with the experimental data available in the literature. The micro-structural model is also checked with experimental data available in the literature. Moreover, a micro/macro-structural analysis is performed on heat on edge weld and head on edge weld for austenitic stainless steel and the results are compared with the experimental and analytical results available in the literature.

abstract: Doctor of Philosophy (PhD)


title: Priscian's De laude Anastasii imperatoris

contributor:
Cameron, Averil
Roman Studies

subject: Roman Studies

subject: Other Languages, Societies, and Cultures

abstract:
Imperil panegyrics have often been dismissed as mere flattery of no literary merit and limited historical value. In recent years, increasing interest in the study if the history of the later Roman empire has led scholars and to take a fresh look at panegyrics and to examine their role in the society of the late antique world. Detailed studies of individual works are necessary for this examination and reevaluation of imperial panegyric. This thesis, consisting of translation and commentary, provides such a study, the first in English, of the Delaude Anastasii impreratoris, a verse panegyric of the emperor Anastasius (491-518) written in Constantinople by the sixth century author Priscian, best known for his work on Latin grammar.

Set in its literary context, the panegyric illustrates one stage in the Christianization of a secular literary genre. To praise his Christian emperor and justify his rule in terms of Christian political theory, the poet abandons the epic style and mythological allusions used by his predecessors in Latin verse panegyric. Instead, Priscian versifies the outline for imperial panegyric provided in rhetorical handbooks. Literary traditions, however, dictates that his language and poetic adornment be neutral, acceptable to both pagan and Christian, and as a result there are few overtly Christian elements in the poem.

In the panegyric; Priscian creates the image of an emperor chosen by God and protected by His might. The skillful development of and emphasis on such an image suggest that historically the poem should be dates to the later part of Anastasius' reign when religious controversy and armed rebellion threatened his throne. More specifically the panegyrist's portrait of the emperor, combined with reference to historical events, indicates that the poem may date to the year 513, the first year of the rebellion of Vitalian. Set in this context, the poem was probably aimed at dissident elements within Anastasius' court and administration.

abstract: Doctor of Philosophy (PhD)


title: Dynamic Modelling of Interstitial Laser Photocoagulation in Soft Tissues

contributor:
Wyman, Douglas R.
Physics

subject: Physics Physics

abstract: Interstitial Laser Photocoagulation (ILP) is a minimally invasive cancer treatment technique whereby optical energy from an implanted optical fiber is used to destroy small, solid tumours. In this work, an optical diffusion approximation and heat transfer equations were used to develop dynamic models of interstitial laser heating. Modifications in the thermophysical and optical properties due to tissue coagulation (T ≥ 60°C) and vaporization of tissue water (T ≥ 100°C) were incorporated into the physical description. In addition, the effect of different blood perfusion approximations on temperature distributions for an in vivo liver model was explored. The calculational results presented indicate the necessity to include dynamic modifications in the tissue biophysical and blood perfusion properties in future parametric investigations of the potential of ILP in various tissues. A quasi-linear model of tissue charring during single fiber ILP was derived. The increase in optical absorption at the fiber tip due to the browning/charring process was modelled as a linear continuous shift in energy deposition from a point optical source to a point heat source. The tissue charring temperature was estimated by placing experimentally measured charring dimensions on calculated temperature profiles. The potential for combining online thermometry with dynamic thermal modelling to reconstruct complete tissue temperature distributions during ILP was also investigated. Features of an on-line temperature reconstruction system have been identified and the physical and technical limitations explored.

abstract: Doctor of Philosophy (PhD)


title: Attenuation Correction in Positron Tomography

contributor:
Nahmias, C.
Medical Physics

subject:
Medical Sciences
Physics
Medical Sciences

abstract:
Accurate attenuation correction is a prerequisite for the determination of precise regional radioactivity concentrations in positron tomography. Attenuation correction can be performed using an external source of radiation and two measurements: a blank scan performed with no subject in the tomograph, and a transmission scan performed with the subject in the field of view. The ratio of blank to transmission counts gives the appropriate attenuation correction factor for each line of response. In theory, this provides a perfect correction for photon attenuation, but in practice the technique is limited by noise due to limited counting statistics and scattered radiation in the measured transmission data.

In the present work, ¹³⁷Cs is proposed as a suitable radiation source for transmission measurements in 'singles' mode, a technique that substantially increases the statistical accuracy of the transmission data. ¹³⁷Cs can be used without any recalibration of the tomograph, and the spatial resolution is comparable to that obtained using ⁶⁸Ge. Since ¹³⁷Cs emits a monoenergetic gamma ray at 662 keV, and emission data are acquired by detecting annihilation photons of energy 511 keV, a simple extrapolation method is developed to extrapolate the attenuation coefficients measured at 662 keV to 511 keV. To eliminate scatter contamination in the transmission data, a dual-energy-window scatter correction technique is developed whereby correction can be made on-the-fly during data acquisition. Using the developed extrapolation method and dual energy scatter correction method, the linear attenuation coefficients measured in 'singles' mode using ¹³⁷Cs agree well with the expected values.

To achieve further suppression of noise in the transmission data, a segmented attenuation correction technique is also developed in this work. The technique uses artificial neural networks for processing the count-limited transmission data. The technique has been validated in phantoms and verified in human studies. The results indicate that attenuation coefficients measured in the segmented transmission images are accurate and reproducible. Activity concentrations measured in the reconstructed emission image can also be recovered accurately with this technique. The accuracy of the technique is subject independent and insensitive to scatter contamination in the transmission data. It can predict accurately the value of the attenuation coefficient for any material in the range from air to water. Satisfactory results are obtained if the transmission data contains as few as 400,000 true counts per plane. Thus, accurate attenuation data can be obtained by acquiring a short transmission scan using the 'singles' method, and then processing these data using the artificial neural network technique.

abstract: Doctor of Philosophy (PhD)


title: Quadrature-Amplitude-Modulated Signalling over a Discrete-Multipath Linear Time-Variant Channel

contributor:
Taylor, D. P.
Wong, K. M.
Reilly, J. P.
Electrical and Computer Engineering

subject:
Electrical and Computer Engineering
Electrical and Computer Engineering

abstract:
In this thesis, a new paradigm is proposed for designing the transmitter and receiver for quadrature-amplitude-modulated signalling over a mobile radio channel. The new paradigm is based on a discrete-multipath linear time-variant model of the mobile radio channel, and hence the title of the thesis. The time-variant input-output relationship of the discrete multipath channel (DMC) is governed by a set of parameters which can be obtained in finite time by probing, that is, by transmitting a pre-assigned signal and then performing computations on the received signal. Therefore, once the parameters of the DMC's input-output relationship have been obtained in this manner, the receiver can, in principle, determine the subsequently transmitted data-carrying signal, or, the data itself, by performing computations on the received signal, which operation is referred to as signalling.

Thus, the thesis proposes a philosophy of design based on alternate probing and signalling, and shows that when the transmitted signal is generated by quadrature amplitude modulation (QAM) the composition of QAM and DMC lends itself to this philosophy of design, even in the presence of intersymbol interference (lSI) and additive white Gaussian noise (AWGN).

As regards probing, it is shown that by transmitting a suitable quadrature-amplitude. modulated signal all parameters of the DMC, or, rather, of the composition of QAM and DMC, can be estimated in the presence of AWGN. In particular, the maximum-likelihood method of estimation is shown to have the statistical properties needed to justify the philosophy of design.

As regards signalling, based on the assumption that the parameters of the DMC, or, rather, of the composition of QAM and DMC, are known by the receiver, it is shown how the receiver may decide which data sequence was likely transmitted, taking into account lSI and AWGN according to some optimal rule. Motivated by the classical receiver design principals used for quadrature-amplitude-modulated signalling over a linear time-invariant channel in the presence of lSI and AWGN, namely.

1. linear zero-forcing equalizer,

2. decision-feedback zero-forcing equalizer,

3. linear mean-square-error equalizer,

4. decision-feedback mean-square-error equalizer,

5. maximum-likelihood sequence estimator of the Forney-type,

6. maximum·likelihood sequence estimator of the Ungerboeck type,

the thesis shows how these principles can be generalized for quadrature-amplitude-modulated signalling over a DMC in the presence of lSI and AWGN. Despite the DMC's being time-variant, these generalized receivers can be implemented with a bank of continuous-time time-invariant filters at the front.

The thesis, although mainly theoretical, illustrates some of the above methods through computer simulations. More specifically, numerical results are given for probing by maximum-likelihood method and signalling by a linear zero-forcing equalizer, under various system specifications and scenarios involving the geometry of propagation and speeds of movement.

abstract: Doctor of Philosophy (PhD)


title: Mass Transfer in Liquid Flow through a Reclangular Channel with and without Thermal Gradients

contributor:
Shemilt, L.W.
Chemical Engineering

subject:
Chemical Engineering
Chemical Engineering

abstract:
The limiting current method was used to investigate the mass transfer to a wall of a rectangular Plexiglass channel operated as a flow reactor for Reynolds numbers ranging from 200 to 32000. Cathode and mode blocks with smooth nickel surfaces were mounted in opposite walls of the channel, flush with the interior surface. Isothermal and non-isothermal mass transfer experiments were performed with the entire horizontal flow channel

i. rotated in 30° increments so that the cathode position varied from facing up to facing down (angle α) ii. tilled in 30° increments so that the channel position varied from horizontal to vertical (angle β)

at various bulk solution and cathode surface temperatures.

lsothermaI experiments (3277 in total) were performed in a flow channel with an internal rectangular cross-section of 2 cm x 1.5 cm (width x height), the total length being 229 cm between inlet and outlet. The electrolyte bulk solution, comprised of 2 mol/l NaOH, 0.025 mol/l K₃Fe(CN)₆ and 0.025 mol/l K₄Fe(CN)₆, was varied in temperature from 25°C to 55°C.

While the bulk solution was maintained at 25°C and the cathode surface temperature varied from 35°C to 55°C, non-isothermal experiments (2394 in total) were conducted in the same apparatus as describe above.

Examination of the data revealed that the mass transfer in the laminar now regime, at Re < 1900, seems to be independent of the Reynolds number. For laminar now conditions an equation of the form

Sh = 0.116 (1 + 0.336 (sinα)²⁷⁶⁶ + 0.427 (sinβ)⁰⁸²⁶(GRmSc)⁰³²⁰

gives an adequate prediction for mass transfer rates at 0° ≤ α ≤ 180° and 0° ≤ β ≤ 60°, where GRm is the combined Grashof number for heat and mass transfer. Mass transfer rates for the channel in a vertical position (β = 90°) can be predicted by:

[equation removed]

For Reynolds numbers greater than 1900, mass transfer was found to be controlled by free and forced convection, with the forced convection dominant. For the turbulent flow region the date for 0° ≤ α ≤ 180° and 0° ≤ β ≤ 60° can be predicted by:

[equation removed]

Mass transfer rates for channel slopes of 90° were best correlated by:

[equation removed]

The isothermal laminar and turbulent experimental mass transfer coefficients were found to be within ±10% of correlations presented by Rousar et al. (1971) and Pickett (1977), respectively. For non-isothermal mass transfer in a horizontal channel under laminar and turbulent flow conditions the correlations of Ajersch (1990) agree well with the experimental data. Non-isothermal operation was found to increase mass transfer approximately four times over the isothermal case under the optimum enhancement conditions.

Since the system under investigation is a couple one, no analytical solution of the growing equations is possible. The finite element solver FIDAP was used to obtain numerically the local mass transfer coefficients, local Reynolds numbers, local densities, stream functions and concentration and temperature profiles for isothermal and non-isothermal case studies. The numerically obtained average mass transfer coefficients agreed within 15% of the experiment values for both the isothermal and non-isothermal case.

abstract: Doctor of Philosophy (PhD)


title: Sedimentology and Paleogeography of a Devonian Turbidite Basin in Argentina

contributor:
Middleton, G.V.
Geology

subject: Geology Geology

abstract:
The area studied lies in central western Argentina, just east of the Cordillera of the Andes, in the geological province names the Precordillera. This thesis describes the sedimentology and paleogeography of the Punta Negra Formation (Middle to Upper Devonian). This formation is well exposed over the central Precordillera by a series of thrust faults which trend north-south. The Punta Negra Formation was deposited on a continental borderland and its distribution and lithofacies were controlled by two north-south trending rises: the Zonda-Villicum arc, on the east, and the Tontal arc, on the west.

The Punta Negra consists of gray shales and conglomerates, on the east, and of olive-green graywackes and shales. with few paraconglomerates, on the west. The eastern lithofacies is considered to have been deposited on a slope bordering the mainland and the western lithofacies - which includes most of the outcrops of the Punta Negra Formation - is though to be a submarine fan deposit. The submarine fan occupied a small basin restricted by the two rises above mentioned. This submarine fan does not fit well in proposed models because the upper and middle fan sections - with deep channels and numerous conglomerates - seem to be absent. Only the outer fan morphology is recognizable. This deviation from the model is attributed to the effect of submarine topography. The source area lat to the southeast, on the mainland.

The graywackes that form the submarine fan were transported mainly as high density turbidity currents. But in the last stages of deposition, grain flow and debris flow mechanisms also acted on the sediment. The result of this combination of mechanisms was a complex grading pattern. In most beds one finds: (i) a thin fine-grained layer at the base; the grain-size rapidly increases and, then, follows (ii) a slight inverse grading which extend up to the middle of the bed, (iii) the central portion of the beds are usually structureless and, finally, follows (iv) a normal grading into the shale layer on top.

A reconnaissance field study of the Regional Geology of the Precordillera was carried out, in order to better establish the paleogeographic setting of the Punta Negra Formation. The rock sequence studied extends from the Precambrian to the Devonian, inclusive, with three intervening unconformities. The Precambrian is barely exposed on the east and consists of schists. The Cambro-Ordovician consists, on the east, of 2000m of shallow water limestones unconformably overlying the Precambrian basement. On the west, shales, turbidites and a few conglomerates probably represent slope, rise and abyssal plain sediments; paleocurrents are mainly from the north. The Ordovician on the west contains pillow lavas and ultrabasic bodies but there is no evidence of an underlying continental basement or of western sediment sources. The Cambro-Ordovician assemblage suggests the existence of a passive, Atlantic-type continental margin. Following a Late Ordovician tectonic disturbance, Silurian and Devonian sedimentation was wholly clastic and controlled by submarine rises. One such rise, the Tontal arc, acted as a barrier to the westward movement of much of the clastic sediment, which paleocurrent and petrography indicates was derived from the shield to the east. Marine sedimentation over the old continental shelf, east of the Tontal arc, was brought to a close by the deposition during the Devonian of thick turbidite beds in at least two submarine Fans, with paleocurrents predominantly from the east and south.

abstract: Master of Science (MS)


title: The Adsorption of Bioresidual Oraganics in a Fluidized Bed Biological Reactor

contributor:
Benedek, Andrew
Chemical Engineering

abstract:
The adsorption of residual organic molecules generated during the metabolic activity of bacteria was investigated.

At first a number of potential adsorbants and ion exchange resins were selected with different average pore diameters and specific surface areas.

The adsorption (removal) capacity of these materials was evaluated through the determination of their adsorption isotherms on a residual organics solution, obtained from an activated sludge reactor, that operated with Phenol as a substrate.

On the basis of these isotherms Filtrasorb 400, an activated Carbon with 35Aº average pore diameter and 1200 m²/g specific surface area, was selected as the best adsorbant. Subsequently a fluidized bed biological reactor was used to study the direct adsorption of the residual organics produced by the biofilms on the Filtrasorb 400 particles supporting the growth. A phenol solution was fed to the reactor and different Oxygen to Phenol ratios were applied.

The adsorption of the residual organics molecules generated by the biological growth in a fluidized bed biological reactor proved feasible and independent of the Oxygen to Phenol ratio applied. The Phenol removal efficiency of the reactor was determined by the Oxygen supplied. The removal reached 100% whenever residual Oxygen was present in the effluent of the reactor (no Oxygen limitation).

Specific reaction rates higher than the ones reported in the literature were observed.

The removal of the residual organics resulted in a stable effluent pH.

The monitoring of the height of the expanded bed that developed biological growth is a parameter that can be used to monitor the total volume of biological films in the reactor. A volume yield can also be calculated.

abstract: Master of Engineering (ME)


title: Reality, Relevance and Reason: A Defence of Scientific Realism about Micro-entities

contributor:
Settle, Tom
Philosophy

subject: Philosophy Philosophy

abstract: The thesis develops and argues for a version of realism about micro entities postulated by scientific theories. It begins with analyses of the concepts of reality, observation, interaction, causality and reasonableness, which are crucial in the modem realism debate. In this way, it is found that, within the debate, a move from the acceptance of the causal role of an entity to the acceptance of its reality is legitimated. Hence "good reasons" for accepting the reality of the entity are those that indicate that its causal relevance to some other objects has been conceptually and experimentally identified. The acceptance is reasonable in the sense that it both is the best choice and is relative, open and critical. Given this recognition, the constituents of "good reasons" for identifying a postulated entity's causal relevance are sought. Such logical attempts as hypothetico-deductivism, Glymour's bootstrapping theory and Sylvan's programme for relevance logics of cause are demonstrated to be incapable of identifying the causal relevance. Hence the "experimental approach" is preferred and developed. An account of good reasons based on a cause identification condition, which consists of a model constituent and an experiment constituent, is proposed, clarified and defended by case studies of models and experiments in elementary particle physics and molecular biology. These experiments are shown for the first time to have a special tree-structure, which reflects a synthesis of their self-checking and -correcting mechanisms and which makes them manipulations of the postulated entity. It is argued that through the tree structure scientists' belief in the reality of DNA molecules is rooted in the nature of the technology used to manipulate them. Finally, with a comparative case study of the neutrino and the ether, the challenge by Laudan (1981) for realism is met and the adequacy of the account of good reasons is further proved. The thesis has philosophically accounted for the reasonableness of scientific belief in the reality of the micro-entity.

abstract: Doctor of Philosophy (PhD)


title: Coupling-of-Modes Studies of Surface Acoustic Wave Oscillators and Devices

contributor:
Campbell, C.K.
Electrical Engineering

subject:
Electrical and Electronics
Electrical and Electronics

abstract:
Recent advances in the area of communications has inspired the concept of ubiquitous coverage onto the market place. A pocket-size mobile unit will be able to provide two-way messaging on a global perspective. In order to realize this "radio on a chip" philosophy small, rugged, low power and inexpensive components must be designed. In this thesis, new circuits and devices that meet this communication challenge are examined. These involve the use of surface acoustic wave (SAW) components and devices.

The coupling-of-modes theory is used to study the effects of injecting a very small stimulus signal into a SAW oscillator loop. This diminutive injected signal may force the loop, if the conditions prevail, to follow and track it. These injection-locked oscillators (ILOs) follow the theory of phase locked loops (PLLs) to provide circuits suitable for amplification and demodulation of digital modulation signals. The locking phase angle of an ILO follows a similar sigmoidal shape found in neurons. An equivalent SAW ILO neuron circuit is presented and further developed into a self organized neural network. The SAW-based ILOs are then modified by controlling the quality factor of the SAW feedback element to produce carrier recovery, analog to digital converters and data multiplexer circuits. A very non-linear, near-chaotic ILO is introduced and examined with the aid of the Duffing equation. The Duffing model accurately verifies a periodic pulse generator employing a driven unlocked SAW ILO.

A crucial component in any communication receiver is a "front-end" filter that eliminates any interfering frequencies that are close-in to the receiver channel. A study of such a component reveals that a dual-mode leaky-SAW resonator filter is ideal for the task. Antenna theory is applied to model the radiation conductance of thick-film interdigital transducers (IDTs) in dual mode wideband leaky-SAW resonator-filters on 64° Y-X LiNbO₃ employing a three-IDT structure. As well, SAW coupling-of-modes reflection-grating equations and IDT S-parameters are modified to cater for increased leaky-SAW attenuation above the Bragg frequency. Theoretical frequency response computations are in excellent agreement with experimental results obtained for several low-loss 85-MHz structures fabricated with metallization film thickness ratios (h/λ) of up to 3%.

abstract: Doctor of Philosophy (PhD)


title: Seismic Analysis of Concrete Gravity Dams With Keyed Contraction Joints

abstract:
Most of the design of concrete gravity dams is based on a two dimensional analysis which is suitable for monoliths with smooth, unkeyed, contraction joints. However, when keyed contraction joints are used, it is expected that the dam monoliths will interact in a manner that may affect the overall response of the system. The objective of this study is to investigate the seismic behaviour of concrete gravity dams, built with keyed contraction joints, including the effect of monoliths interaction. The scope of research work included: 1) development of a simplified procedure to investigate the effect of monoliths interaction on the seismic behaviour of the structure, 2) after this was proved to be important, a detailed and comprehensive procedure was developed and 3) investigation of the parameters which affect the response of the structure and significantly influence monoliths interaction.

In the simplified procedure, each monolith of the dam is modeled using beam elements which has the advantages of keeping the number of degrees of freedom to a minimum and being available in most of structural engineering computer codes. The approximate added mass technique is used to simulate the hydrodynamic effects when the dam and reservoir are subjected to an earthquake ground motion. The importance of including monoliths interaction is illustrated by analyzing different cross-sections of concrete gravity dams.

In the proposed detailed analysis of gravity dams, a substructuring technique is employed to model the structure. The dam is divided into a number of substructures equal to the number of monoliths. Each monolith is then reduced to a few degrees of freedom on the upstream face and Ritz vectors are used to represent internal degrees of freedom. The analysis is carried out in the frequency domain to include the frequency-dependent terms which appear when including reservoir-darn-foundation interactions. The results obtained are compared to typical three-dimensional analysis and a good agreement is obtained. It is noted that the importance of monoliths interaction is dependent on two factors; 1) the type of contraction joints used in construction and 2) the longitudinal profile of the dam.

The effect of monoliths interaction is to increase the natural frequencies of the structure and as a result leads to a change in its overall response. It is concluded that in many cases the effect of monoliths interaction is important and should be included in the analysis. The geometry and material properties of contraction joints have a significant effect on the overall response of the dam. Depending on the crack width, the shear behaviour of the joints varies widely. The longitudinal profile of the dam was also found to have a substantial effect on monoliths interaction. Important variations in the response of the dam, from that calculated using typical two-dimensional analysis, is obtained for some cases. This is usually the case for short dams with rigid monoliths at the sides or for dams built in steep canyons.

abstract: Doctor of Philosophy (PhD)


title: Only Connections: The Representation of Community in Four English Novels

contributor:
Ross, Michael
English

subject:
English Language and Literature
English Language and Literature

abstract:
This dissertation illustrates the changes that have occurred in the representation of community from the publication of Henry Fielding's Joseph Andrews in 1742, through Jane Austen's Persuasion (1818) and George Eliot's The Mill on the Floss (1860), to the appearance of E.M. Forster's Howards End in 1910. Using the theories of Richard Rorty's Contingency, Irony, and Solidarity and Ernesto Laclau's and Chantal Mouffe's Hegemony and Socialist Strategy, the dissertation argues that not only ideological harmony but also difference - violence, antagonism, the clash of vocabularies - constitute the community. As a result, social and communal space is never, to use the words of Laclau and Mouffe, "fully sutured." The essential unity for which community strives is perpetually denied. The thesis discusses the solutions each author employs to bridge this fundamental gap and traces the growing awareness of community as an object influenced by difference.

In Joseph Andrews, where Fielding attempts to defend the values of a status quo corrupted by the elites who most profit by it, the proper community is understood to resist difference. But the actions of the novel's characters, who often take matters into their own hands to establish the communal "law," tell a different story. Joseph's and Parson Adams's willingness to employ force to achieve their ends results in a kind of "irregular justice" that overlies community values and demonstrates the need for individual action to maintain that community.

Similarly, Jane Austen regards individual action as necessary for the life of the community. She goes even farther, however, by accepting the implications of this view: that communities are made, not simply inherited. In this way she is more like the Romantics than is generally assumed. George Eliot continues where Austen leaves off. Having assimilated Austen's insight regarding the artificial, fabricated nature of communities, Eliot seeks a method to overcome the disjunction between the ideas of the past and the ideas of the present. She recommends that imagination serve as the individual's tool for smoothing the bumps of disagreements between vocabularies. Maggie Tulliver adopts this advice; the rest of her community does not and fails her as a result. Finally, Howards End presents a community that is entirely self-constructed, one without the tensions suffered in the earlier novels between the established order and individual desire. The novel completes the redescription of community the other novels begin. Forster consequently celebrates difference and attempts to enshrine it by "only connecting" the novel's various vocabularies. If he rightly suggests the degree to which community, as a constructed object, relies on individuals, he perhaps exceeds his reach by proposing that "connection" somehow escapes ideology. Even so, Howards End gathers within itself the concerns of the three previous novels and demonstrates what Rorty, Laclau and Mouffe assert: that community cannot evade the individual's contribution. The definition of any given ommunity is constantly in play.

abstract: Doctor of Philosophy (PhD)


title: Representativeness and Bias in Cemetery Samples Implications for Palaeodemographic Reconstructions of Past Populations

contributor:
Saunders, S.R.
Physical Anthropology

subject: Anthropology Anthropology

abstract: This study examines the issue of representativeness with respect to palaeodemographic reconstructions from skeletal remains. Since determination of age and sex is fundamental to research in skeletal biology, it seemed warranted to examine the impact of representativeness and bias on interpretations based on these data. Mean age-at-death (MAD) is the primary statistic relied upon for interpretations of changing patterns of health and well being from palaeodemographic analyses. This study examines the issue of representativeness between skeletal samples and the cemetery population from which they are drawn. A series of sampling experiments conducted on three documented 19th century mortality sample distributions (St. Thomas' Anglican, Belleville, Union Cemetery, Waterdown, St. Luke's Anglican, Burlington) illustrates the danger in making interpretations based on mean age-at-death. It is proposed that whatever process mean age-at-death reflects in the health of past populations (fertility or mortality), it is irrelevant if the sample on which the statistic is calculated is not representative of the population. Given that most cemetery samples will be subject, differentially, to biases at a variety of levels, comparative studies based on palaeodemographic data cannot realistically be considered reliable without careful control for those biases. Without careful consideration of what or who exactly is represented by skeletal samples, palaeodemographic analyses shed little light on the realities of past life. If representativeness is, as I would suggest, the primary theoretical obstacle for researchers to overcome, then it is necessary to shift our focus to rigorously exploring those factors that bias our samples. Without some direct quantification of the representativeness of a sample, palaeodemographic estimators such as mean age-at-death are meaningless and any subsequent interpretations regarding the past, dubious at best.

abstract: Doctor of Philosophy (PhD)


title: From There to Here: Writing, Exploration and the Colonizing of Canada

contributor:
Clark, David
English

abstract:
My thesis traces the historical and theoretical formation of a "Canadian" writing. Traditionally, Canadian literature and the "Canadian identity" have been studied thematically. For instance, our relationships to wilderness, animals and geography (the inhospitable land), and the sense of community that develops in reaction to these circumstances are themes which have been examined exhaustively. In contrast, I am theorizing how writing was practiced in seventeenth-eighteenth- and nineteenth-century Canadian exploration narratives. The main chapters of this thesis are separated by shoner, more detailed. analyses of visual works, including maps, engravings from exploration books, and Frances Anne Hopkins's voyageur paintings. My explication of these pictures works dialectically with the longer chapters on prose narratives to reveal different aspects of exploration's expansive colonial discourse.

In chapter two I identify four distinct forms of writing, including "writing as inscription," the physical act of inscribing on surfaces. These surfaces include the North American landscape where territory is claimed in the name of a sovereign and as an act of imperial expansion. I also discuss writing's role as an agent of capitalism: it structures systems of exchange and records the European's interventions into indigenous cultures. Writing is a portable technology which the explorers use to transmit and store information on the peoples and geographies of the newly found lands.

Chapter four discusses the early sea voyages of Thomas James (The Strange and Dangerous Voyage of Captain Thomas James and Luke Foxe (North-West Fox, or. Fox from the North-west Passage). Both men found an inhospitable land barren of resources which would not yield a North West Passage. In chapter six Samuel Hearne's A Journey from Prince of Wales's Fort in Hudson's Bay...to the Northern Ocean provides an exemplary model for the role of commerce in the eighteenth century. Hearne's narrative is the most important and influential of the many first-person narratives written by traders in the eighteenth and nineteenth centuries and his geography is much more detailed and economically productive than those of James and Foxe because he explores for trade and mining purposes.

The thesis ends with a reading of the three Franklin expeditions. Although the published texts only detail the first two (Narrative of a Journey to the Shores of the Polar Sea and Narrative of a Second Expedition to the Shores of the Polar Sea), the loss of Franklin and his men with the third expedition, and the enormous media interest in the subsequent searches for their various "traces," demonstrates the entry of explorers into the "modern" world of communications technologies. The contemporary image of Franklin which has been recuperated through forensic technology mirrors the technology of writing discussed throughout the thesis. My analysis of exploration narratives and the extensive role of writing throughout the colonizing of Canada offers a valuable insight into our literary and cultural history.

abstract: Doctor of Philosophy (PhD)


title: Re-casting the Midwives of Modernism: Autobiographies of American Expatriate Women Publishers and Editors

contributor:
Coldwell, Joan
English

abstract:
The expatriate literary community in interwar Paris included a number of women whose private presses and little magazines stimulated the creation of experimental literature by printing works certain to be rejected by mainstream publishing houses. These publishers and editors have traditionally been cast as the midwives of modernism. Literary histories relegate them to traditional female roles - or ignore them altogether. Feminist scholarship has recently begun to uncover the full extent of the women's influence; however, the body of self-representational literature they produced continues to be neglected or misread. This thesis examines Sylvia Beach's Shakespeare and Company, Caresse Crosby's The Passionate Years, and Margaret Anderson's My Thirty Years' War.

Conscious that her adoption of an autobiographical voice breaches cultural scripts of self-effacing womanhood, Sylvia Beach downplays her role as bookseller, librarian and publisher to foreground instead a more conventional, maternal role. Details of her literary labours, particularly those arising from her publication of James Joyce's Ulysses, are selectively interspersed amidst accounts of personal favours performed for her clientele. Invoking a domestic discourse to represent Shakespeare and Company, Beach disguises her bid to establish the bookstore as a landmark of modernism.

Like Beach, Caresse Crosby revises standard (male) histories of expatriate Paris by situating her autobiography within a domestic realm and not the public space of Left Bank cafés. The Passionate Years highlights Crosby's status as a glittering society hostess whose parties attract international attention. The depiction of her social preeminence comprehends claims of her artistic influence: Crosby's guests at her Moulin de Soleil include writers and artists whose works she published at her Black Sun Press.

Margaret Anderson too collapses the distinction between home and workplace. My Thirty Years' War depicts how she edits the Little Review at her kitchen table; furthermore, her journal and domestic space are upheld as equally valid vehicles of creative self-expression. Anderson's credo of "life-as-an-an" encapsulates the integration of everyday life and artistic concerns common to all three autobiographies: an integration which mutes the authors' claims of literary authority but also, more fundamentally, reflects their experiences as women. These autobiographers, then, challenge androcentric models of modernist autonomy as they reposition themselves as the mothers, not midwives, of modernism.

abstract: Doctor of Philosophy (PhD)


title: Reduction of the Coolant Void Reactivity Effect in a CANDU Lattice Cell

contributor:
Garland, Wm. J.
Milgram, M.S.
Engineering Physics

subject:
Engineering Physics
Engineering Physics

abstract: A positive feedback mechanism linking reactor power and loss of coolant exists in the current configuration of the CANDUˣ reactor. This mechanism creates a "coolant void effect" which is accommodated in both the safety system and control system designs: .although a political incentive exists to reduce the effect's magnitude. This dissertation includes a review of current methods and knowledge in the area of CANDU lattice cell analysis of the coolant void effect, presented in two parts: (1) an investigation of the methodology and modelling, and (2) an investigation of the contributing reactor physics. This study also explores several routes toward the goal of reducing the coolant void effect, drawing from both existing work and original contributions. A novel approach to CANDU fuel design is defined, combining the concepts of coolant displacement, concentritubular fuel, and differential uranium enrichment. Several variations of the new design are discussed, as well as practical difficulties that would be associated with the realization of this design. Finally, a corrective algorithm is developed and utilized which compensates for a modelling deficiency arising in the simulation of tubular fuel.

abstract: Doctor of Philosophy (PhD)


title: Analytical Electron Microscopy and Creep Deformation of Sintered Silicon Nitride

contributor:
Wilkinson, D.S.
Materials Science

subject:
Materials Science and Engineering
Materials Science and Engineering

abstract:
Silicon nitride is sintered with the use of additives, such as Y₂O₃ and Al₂O₃, in order to enhance densification. After sintering, these additives along with SiO₂, present on the starting Si₃N₄ powder, form an intergranular amorphous phase. The presence of a glassy phase is generally thought to be detrimental to the high temperature creep properties. In the material analyzed, Kyocera SN220, this intergranular glassy phase partially devitrifies upon annealing. Thus the effect of a fully amorphous or a partially crystalline intergranular phase on the creep properties could be assessed. The creep resistance of the material is only modestly affected by partial grain, boundary devitrification in both flexural and compressive creep. However the creep life is reduced significantly.

Extensive analytical microscopy was done on the amorphous and partially crystalline material in order to determine what changes were occurring due to anneling and due to creep deformation. A quantitative methodology was developed for electron energy loss spectroscopy to analyze the intergranular phase composition. Using this technique concentrations of light elements, such as oxygen and nitrogen, and heavier elements could be determined. Different crystalline grain boundary products were found near the surface of samples annealed in air compared to the centre of these and throughout samples annealed in an inert atmosphere. However the residual amorphous phase composition was the same regardless of annealing atmosphere or location. In addition, phases present after devitrification did not depend on the stress state. Extensive cavitation, a commonly observed effect of creep, did not occur in samples containing the maximum obtainable strain in flexure of 2.7%.

The observed microstructural information and creep data was taken into consideration in developing a creep model. This model describes creep due to non-linear viscous flow of an amorphous intergranular phase around a hexagonal array of grains. An initial constant strain rate is predicted at low strains, followed by a decrease in strain rate as the intergranular phase is squeezed out from between grains. This decrease occurs at smaller strains in compression than in tension or flexure. The creep behaviour observed experimentally corresponds well with that predicted theoretically.

abstract: Doctor of Philosophy (PhD)


title: Modelling of Regional Networks for Minimum Cost

contributor:
Smith, Alan A.
Civil Engineering

subject:
Civil Engineering
Civil Engineering

abstract:
A computer model is developed for the solution of regional network systems on a minimum cost basis. Different network problem types are identified to define the scope of the model. Generally, the problem involves the determination of the optimum conveyance schedule required to supply a set of consumer nodes with a commodity or public service provided by one or more processing centres (i.e. water supply, solid waste or wastewater collection networks). The system costs include costs incurred due to conveyance of material and the processing of that material; both of these cost components exhibit economies of scale and generally lead to the centralization of processing.

A mathematical statement of the problem is developed which is applicable to all network types, can be utilized easily and efficiently in a digital computer and facilitates the use of a variety of optimization routines. A number of algorithms, ranging from linear approximation to nonlinear gradient search routines, are investigated for possible inclusion in the model with the advantages and disadvantages of each being identified.

A modular package, NETSOL, is developed which facilitates the use of alternate optimization routines and allows for the inclusion of complex design functions in the computation of system costs. An interactive command structure permits the user to modify the network system parameters thereby combining intuitive design with the capacity to select an optimal solution from a large number of alternatives. Thus a model is obtained which is flexible enough to answer many of the questions that arise in network problems and also determine the optimum.

In view of the disadvantages found in the existing optimization techniques (e.g. convergence to local minima), the properties of the network problems are investigated in detail to isolate any special characteristics. For a system involving separable concave cost functions, the minimum cost solution to a network problem lies at one of the vertices formed by the problem constraints. A new solution algorithm, HYVRST, is developed which takes advantages of this important property utilizing a direct search technique. This results in an efficient and stable algorithm with good convergence properties. A number of example are presented to test the optimization algorithms and demonstrate the usefulness of the NETSOL package in solving regional network problems.

abstract: Master of Engineering (ME)


title: Syntheses and Investigations of Bi- and Trimetallic Organotransition Metal Clusters

contributor:
McGlinchey, M.J.
Chemistry

subject: Chemistry Chemistry

abstract:
The reaction of dicobalt octacarbonyl with a series of 1,1,1-trichloro-2,2-bis(aryl)ethanes yields the corresponding Co₃(CO)₉[μ³-CCHRR'] tetrahedral clusters, where R= R' = 4-methoxyphenyl or R = 4-chlorophenyl, R' = 2-chlorophenyl. The nine-fold degeneracy of the cobalt carbonyl ligands in these clusters is split on the NMR time-scale at low temperature. In order to investigate the fluxional processes, the three axial carbonyl ligands were replaced by the tripodal moiety HC(Ph₂P)₃. The molecular structure of (HC (Ph₂P)₃)CO₃ (CO)₆[μ³-CCH₃] was determined by using X-ray crystallography. These data, in conjunction with the variable-temperature NMR results revealed the existence of several independent fluxional processes.

A series of enantiomerically pure dicobalt μ-alkyne clusters which possess diastereotopic cobalt vertices were synthesized by the treatment of [CO₂ (CO)₆] [HC≡C-CH₂OH] with menthol or borneol, or by the reaction of Co₂ (CO)₈ with 2-endo-propynyl-borneol; the latter cluster was characterized X-ray crystallographically. Carbonyl substitution by phosphines occurs with some degree of diastereoselectivity. Moreover, diastereoselective replacement of a metal vertex by isolobal groups (C₅H₄R)M(CO)₂, where R = H or CH₃ and M = Mo or W, has been observed by using NMR spectrosopy.

The reaction of [(C₅H₅)Mo(CO)₂]₂ with 2-endo-propynyl-borneol yields the crystallographically characterized tetrahedral cluster (R*C≡≡CMe)Mo₂ (CO)₄ (C₅H₅)₂, where R* is the 2-norbornenyl group. Protonation of this cluster and the above-mentioned hexacarbonyldicobalt species leads to metal stabilized cations which maintain their terpenoid skeletons and are stable towards carbocationic rearrangement. High field NMR studies on the mixed metal cationic clusters [M-Co (CO)₃ (HC≡C-CR₂)]⁺, where M = (C₅H₅)Mo(CO)₂, (C₅H₄Me)W(CO)₂ or (C₅H₄Me)Mo(CO)₂, reveal that the capping vinylidene moiety leans preferentially towards one vertex. NMR data, together with EHMO calculations, on the related trimetallic cluster cation [(C₅H₅)Mo(CO)₂CO₂(CO)₆CCR₂]⁺ demonstrate that the positive charge is better tolerated by the (C₅H₅)Mo(CO)₂ fragment than at the Co(CO)₃ vertex.

abstract: Doctor of Philosophy (PhD)


title: Characterization of Cellular Proteins Found in Association with Early Region 1a Polypeptides of Human Adenovirus Type 5

contributor:
Branton, Philip E.
Biology

subject: Biology Biology

abstract:
Human adenoviruses are capable of oncogenic transformation of mammalian cells in culture and are a a valuable model system for use in studying the molecular basis of cancer. The Early Region 1A (E1A) gene of the virus is involved in transformation, and its protein products have been previously reported to associate with cellular polypeptides termed p300, p107, p105, p68 and p65. The objective of the present investigation was to characterize these cellular proteins and to determine something of their function or biological significance with respect to Ela-mediated transformation.

It was found that p300, p68 and p65, as well as a number of other cellular proteins were able to bind with specificity to bacterially-produced Ela products covalently linked to Sepharose beads (Ela-Sepharose), suggesting that this would be suitable for affinity purification of Ela-binding proteins.

The binding sites for p300, p107 and p105 on the Ela polypeptides were mapped in a collaborative study with Dr. Stan Bayley's lab. A region at the amino terminus of Ela proteins was involved in binding p300, and p107 and p105 bound overlapping regions in CR2. CR1 played some role in binding all three proteins, but probably not as a primary binding site. Ela proteins which failed to bind either p300 or p105 were transformation defective, which indicated a role for both proteins in Ela-mediated transformation. Ela proteins which failed to bind both p300 and p105 were incapable of inducing DNA synthesis in quiescent cells, suggesting these proteins were cooperatively involved in suppressing DNA synthesis. p105 was confirmed to be the product of the retinoblastoma tumour suppressor gene, p105-Rb. Comparison of the peptide digestion products of p107 and p105-Rb and examination of the expression of p107 in retinoblastoma cells suggested that p107 and p105-Rb are from different, but related genes.

abstract: Doctor of Philosophy (PhD)


title: Surface Segregation on Co-Rh and Oxidation of Ni-Co Alloys

contributor:
Smeltzer, W.W.
Underhill, P.R.
Thompson, D.A.
Materials Engineering

abstract:
Two model systems, Co-Rh and Ni-Co, were used to study surface segregation and oxidation phenomena on binary alloys.

Cobalt was found to sputter preferentially from five Co-Rh alloys ranging in composition from 19.3 to 84.7 at % Rh when irradiated by 4 keY Ar⁺ ions. Surface segregation experiments on this system in the temperature range 623 to 1123 K showed that cobalt was enriched on the surface of a 84.7Rh alloy while rhodium enrichment was determined for a 19.3Rh alloy. No conclusive segregation could be measured on the surface of a 47.8Rh alloy. The variation of surface concentration with temperature indicated enthalpy values of 1 ± 1 kJ mol‾¹ and -3 ± 7 kJ mol‾¹ for the 19.3Rh and 84.7Rh alloys, respectively. Reasonable agreement was found between these measured enthalpy values and those calculated from the combined bond breaking and lattice strain models of surface segregation.

Oxidation experiments were performed on (110) Ni-3.86Co and Ni-4.0Co polycrystalline alloys at temperatures in the range 673 to 1073 K and a pressure of 5x10‾³ Torr. The effects of surface pretreatment and orientation of the alloy surfaces were correlated to differences in oxide morphology and growth rates. Single crystal specimens which were chemically polished, annealed in vacuum and initially exposed to oxygen at room temperature showed a tendency to form (100) (NiCo)O ⎮⎮ (110) Ni-3.86Co. These layers also exhibited the slowest growth rates and greater enrichment of CoO from the inner to outer oxide surfaces. Single crystal surfaces prepared by chemical polishing, annealing in vacuum and initial exposure to oxygen at the reaction temperatures developed additional oxide orientations parallel to the underlying alloys. Finally, the polycrystalline Ni-4.0Co specimens which were prepared by mechanical polishing followed by exposure to room temperature oxygen developed polycrystalline oxide films. These types of structures were associated with higher rates of oxide growth and lower enrichments of CoO from the inner to the outer oxide surfaces.

The experimentally measured composition profiles were analysed according to the Wagner(⁶) model of oxidation, modified to include the effects of short circuit grain boundary diffusion. Effective alloy interdiffusion coefficients were calculated which showed that the rate of transport in the alloy zone beneath the growing oxide layer was enhanced relative to that expected solely on the basis of volume diffusion in this phase. The results were rationalized according to a dislocation model for the accomodation of plastic strain and vacancy annihilation in cation conducting scales(¹⁴⁹).

abstract: Doctor of Philosophy (PhD)


title: The Sacred Presence of the Guru: The Velala Lineages of Tiruvavatuturai, Dharmapuram, and Tiruppanantal

contributor:
Younger, Paul
Religious Studies

subject:
Religious Studies
Religion
Religion

abstract: [missing page 237]

abstract:
This thesis examines a set of Saiva religious institutions, the Tiruvavatuturai Adhinam, the Dharmapuram Adhinam, and the Kasi Matha of Tiruppanantal, all located in Tamilnadu, india. Preliminary research indicated that models of monastic retreat and seminary yield incomplete and sometimes distorted pictures of the institutions in social setting. Mindful of the dynamic character of these institutions, this thesis endeavours to construct a better model of understanding the institutlons' basic structure.

This work used a variety of sources to gauge the institutions scope of activity. These sources ranged from classical material, inscriptions, hagiographies, doctrinal and ritual writings, to contemporary records first-person observation and interviews. In addressing the question of basic structure, the thesis argues that though these three institutions are conveniently called Saiva matas, the matam and the religious institutions represent two different abstract entities.

The work suggests that the religious institution is structured around the concept of lineage. The institution is above all an aggregate of religious individuals tied together by "fictive kin" ties. Though ascetic, the members of the institution are individuals who see themselves as related to each other through their relationship to a line of preceptors, from whom they are reborn through the rites of initiation. The work discusses in some detail the nature of the different stages of initiation, it examines how group membership is articulated in ritual patterns, and it establishes that the self-identity of the group as a whole is intimately tied in with its description of its pedigree.

The work also demonstrates that the matam, as part of the Hindu temple complex, often housed religious groups such as those studied, but the matam and the religious institution defined by the group are not coterminous. The thesis demonstrates that the matam is a site within the Hindu temple complex where ritualized forms of gifting occurs and suggests that a specific form of dana (gifting) informed by values of lineage propitiation helps account for the settlement of ascetic lineage groups at temple sites.

abstract: Doctor of Philosophy (PhD)


title: Syntactic modeling of multi-function radars

contributor:
Haykin, Simon
Electrical and Computer Engineering

subject:
Electrical and Computer Engineering
Engineering
Electrical and Computer Engineering

abstract:
The problem of radar modeling is of critical importance to Electronic Warfare applications such as radar recognition and threat analysis. As modern radar signals become steadily more complex, so do the issues associated with radar modeling and signal processing. Traditional, data-centric approaches to radar signal processing can no longer cope with the increasing complexity of radar signals. The main contribution of this thesis is the novel, model-centric approach to radar signal processing that utilizes methods from the theory of formal languages and syntactic pattern recognition.

In this thesis, we focus our attention on modeling of Multi-Function Radars (MFRs)---the class of radars that currently presents the greatest challenges to the radar signal processing community. The characteristic feature of MFRs is the complex hierarchical signal structure often utilized by these radars. This complexity in MFR signals makes the classic radar signal processing techniques inadequate.

We consider MFRs as stochastic discrete event systems that are "communicating" information using some stochastic formal languages. We then show how these languages can be modeled by grammars that can be derived using a priori information available in the databases of electronic intelligence. We also demonstrate how these grammars can capture the complex MFR signal structures and exploit the relationships between the internal processes within MFRs and signals emitted by these radars. We refer to this MFR modeling approach as "syntactic modeling".

We also take advantage of the hierarchical nature of the MFR signals and develop a layered radar model where processing of related features of radar signals is confined to a certain modeling layer, and only the information relevant to the next layer of radar signal processing in propagated forward. This hierarchical radar modeling approach enables to keep the complexity of MFR models manageable.

We demonstrate the applicability of the developed approach using computer simulations of synthetic MFR signals and provide two complete case studies demonstrating how the principles developed in this thesis can be applied to modeling of real-life MFRs.

abstract: Doctor of Philosophy (PhD)


title: Ion Beam Mixing and Electrocatalytic Characteristics of Thin Film Ni/Pd Surface Alloys

contributor:
Thompson, D.A.
Smeltzer, W.W.
Davies, J.A.
Materials Science and Engineering

abstract: Atomic mixing resulting from heavy-ion bombardment of thin-film Ni/Pd bilayers and thin Pd markets sandwiched between two Ni layers has been investigated. Experiments were carried out using 120 keV Ar⁺ and 145 keV Kr⁺ ions for doses 0-4x10¹⁶cm⁻² over a wide temperature range (40-673K). The resulting interdiffusion was measured using 2 MeV ⁴He⁺ ion backscattering in-situ. In some cases, additional depth analysis was undertaken using Auger Electron Spectroscopy (AES) with sputter depth profiling. The influence of film microstructure and bombardment-induced microstructural changes on the mixing have been assessed with transmission electron microscopy (TEM). The electrocatalytic behavior of the ion-mixed bilayer samples was determined for the hydrogen evolution reaction in strong KOH solution, using potentiostatic polarization techniques. The amount of ion beam mixing is found to vary with the square root of the ion dose for temperatures ≤ 573K. Also, at 40K, where it is assumed that no significant thermally activated process contributes to the mixing, it is found that the mixing is dependent on the damage energy, FD(subscript, see original file), deposited at the interface region. Between 40 and ~400K, the mixing parameter shows a weak temperature dependence with an apparent activation energy Ea ~ 0.1eV. This suggests that some interstitial diffusion contributes to the inter-mixing in this temperature regime. Above ~ 473K, the mixing (at each temperature) increases rapidly with ion dose for ir radiation doses ≤ 5x10¹⁵cm⁻² with high initial mixing efficiencies of 6-35 atoms/ion between 573-673K. This initial rapid mixing level eventually slows to a less rapid (~1.2 atoms/ion at 673K) rate for doses ≥ 5x10¹⁵cm⁻². TEM observations of the irradiated and unirradiated films suggests that the change to a less rapid mixing rate is correlated with an increase in the average grain diameter (10-80nm) in the film following ion bombardment, and therefore with a reduction in the contribution of grain boundary diffusion to the intermixing. For samples annealed, without irradiation, below ~ 473K, no measurable interdiffusion of the Ni/Pd layers was observed. For samples annealed above ~473K, Whipple analyses of the interdiffusion show two distinct regions - lattice diffusion-dominated region near the original interface and grain boundary diffusion dominated region further away from the interface. The lattice diffusivities, Dℓ(subscript), under thermal annealing conditions were evaluated and ranged from ~ 0.22 to 52x16⁻¹⁶cm⁻²-sec⁻¹ for Pd diffusing in Ni, and 0.33 to 56.6x10⁻¹⁶cm²-sec⁻¹ for Ni diffusing in Pd between 523-673K. These lattice diffusivities are high because of enhancement of diffusion by defects present in the as-prepared films. The grain boundary diffusion coefficients (for Pd diffusion in Ni boundaries) DB(subscript) varied from ~ 5.4x10⁻¹⁴cm²-sec⁻¹ at 523K to ~ 3x10⁻¹¹cm²-sec⁻¹ at 623K, with an apparent activation energy EB(subscript) ~ 1.35 eV and a prefactor D⁰B(subscript) ~ 0.75 cm²-sec⁻¹. Under irradiation conditions, ion irradiation results in an enhancement of the mixing especially below ~ 400K where almost an order of magnitude enhancement over thermal anneal only, was observed. At ~ 673K, the contribution of equilibrium defects to interdiffusion over-whelms the irradiation effects. The diffusion coefficients under irradiation, Drad(subscript), were also evaluated and ranged from ~4 to 70x10⁻¹⁶cm²-sec⁻¹ at 523 and 673K with apparent activation energy Ea ~ 0.57 eV. For Pd films deposited on large-grain Ni substrates, thermal annealing and/or bombardment result in mixing levels that are almost two orders of magnitude lower than observed from small-grained Ni/Pd couples, though under irradiation conditions, radiation enhancement of the mixing was also observed. As potential electrocatalysts for the H₂ evolution reaction in strong KOH solution, the ion-beam mixed surface alloys (in the over-potential range ≤ 0.4 V) show superior performance over smooth Ni, and Ni coated with evaporated Pd.

abstract: Doctor of Philosophy (PhD)


title: Advanced array processing in the presence of complicated spatio-temporal sources

contributor:
Gershman, Alex B.
Electrical and Computer Engineering

abstract:
Array processing has been successfully applied in many areas such as radar, sonar and wireless communications. Most conventional array processing techniques are based on idealistic assumptions that are not valid in many practical situations. This thesis contributes to the development of novel array processing techniques for direction finding and parameter estimation in the presence of complicated spatio-temporal sources.

We address the problem of estimating the Directions-Of-Arrival (DOAs) of weak desired sources observed in the background of strong interference. We develop a new approach to beamspace preprocessing with improved robustness against out-of-sector interfering sources. Our techniques design the beamspace matrix filter based on proper tradeoffs between the in-sector (passband) source distortion and out-of-sector (stopband) source attenuation. We also introduce the novel concept of adaptive beamspace preprocessing that offers a significant improvement in the DOA estimation performance. Computationally efficient convex formulations for these beamspace matrix filter design problems are derived using second-order cone (SOC) programming.

We also develop a generalized Capon spatial spectrum estimator for localizing multiple incoherently distributed sources in sensor arrays. The proposed generalized Capon technique estimates the source central angles and angular spreads by means of a two-dimensional spectral search. The proposed method has a substantially improved performance compared to several popular spread source localization techniques.

A new search-free ESPRIT-type algorithm for estimating the DOAs of multiple chirp signals using Spatial Time-Frequency Distributions (STFDs) is developed. An averaged STFD matrix (or multiple averaged STFD matrices) is used instead of the covariance matrix to estimate the signal and noise subspaces. The proposed algorithm is shown to provide significant performance improvement over the traditional ESPRIT algorithm for FM sources, specifically in situations with closely-spaced sources and low Signal-to-Noise Ratios (SNRs).

We also develop a new algorithm for estimating the parameters of multiple wideband polynomial-phase signals (PPSs) using sensor arrays. Our approach is based on extending the high-order instantaneous moment (HIM) concept by, introducing a new nonlinear transformation called the spatial high-order instantaneous moment (SHIM). We apply this transformation to multiple wideband PPSs and employ the resulting SHIM to provide recursive estimates of the PPSs parameters. The data received at each sensor yields a different estimate of each frequency coefficient. Employing the multiple estimates simultaneously, the proposed algorithm removes the outliers and obtains a better final estimate. STFD-based methods are used in conjunction with the SHIM to estimate the DOAs of the observed signals. The proposed algorithm is shown to have an improved performance compared to the well-known chirp beam-former approach [31]. Furthermore, our algorithm is computationally more attractive as it requires multiple one-dimensional searches instead of a multi-dimensional search.

abstract: Doctor of Philosophy (PhD)


title: The Mineralogical Composition of the Carbonate Rocks of the Kirkland lake-Larder Lake Gold Camp

contributor:
Crocket, J. H.
Grundy, H. D.
Geology

subject: Geology Geology

abstract:
The quartz-carbonate horizon of the Kirkland Lake-Larder Lake area of Ontario is the subject of continuing controversy over its origin, and relationship with the surrounding rocks and the many gold occurrences.

Part of the essential information required is the carbonate mineralogy of the rocks. In the past the carbonate minerals have been identified by optical and presumably chemical means.

In the present study the carbonate mineralogy was determined using X-ray diffraction and scanning electron microscopic techniques. To the author's knowledge, this is the first time these techniques have been employed in an analysis of the quartz-carbonate rocks of the Kirkland Lake-Larder Lake area.

The quartz-carbonate rocks consist mainly of quartz, magnesite, dolomite, chlorite, albite and muscovite with accessory amounts of pyrite, rutile, talc and possibly leucoxene and ankerite.

A semi-quantitative estimate of the percentages of quartz, dolomite and magnesite was made using X-ray diffraction, and two series of prepared standards.

The possibility of a correlation between the carbonate mineralogy and known gold deposits was also explored. The data obtained in this study tend to tentatively suggest a positive correlation between magnesite in the quartz-carbonate rocks and the known gold deposits.

abstract: Master of Science (MS)


title: Protecting Ontario's Wilderness: A History of Wilderness Conservation in Ontario, 1927-1973

contributor:
Weaver, John C.
History

subject: History History

abstract:
Wilderness has been touted as an integral part of Canadian culture. But, from 1927 to 1987, Ontario wilderness conservationists, failed to attract wide popular support. They exerted an influence on provincial park policy, far beyond the strength of their small numbers. In several campaigns, conservationists convinced politicians and civil servants to adopt more protectionist park policies. This record was the result of individual efforts, organization and perseverance. Conservationist lobbying tactics -- from quiet diplomacy before 1987, to mass-media manipulation thereafter -- reflect the changing Ontario political culture. By the early 1970s, they had fostered a more broadly-based preservation movement.

Conservationists promoted different ideas of wilderness. Both the Ontario Department of Lands and Forests, and the Canadian Quetico-Superior Committee (1949) --- reorganized as the Quetico Foundation (1954) -- embraced multiple use. If It enabled the harmonization of natural resource extraction with the protection of scenic and recreational values, by no-cut shoreline reserves along canoe routes. The Federation of Ontario Naturalists (1931) advocated the conservation of wilderness for its own sake. Motivated by scientific and aesthetic appreciation, the naturalists successfully lobbied,for publicly-owned, rigidly controlled nature reserves. Environmental awareness in the 1980s fed a resurgence and refinement of the ecological wilderness concept. This awakening spawned a new pressure group -- the Algonquin Wildlands League (AWL, 1988). It championed a wilderness free of interference with ecological processes, especially resource extraction and recreational overuse.

The AWL built Ontario's modern wilderness preservation movement. By publicizing its wilderness philosophy, the league strengthened the Parks Branch in departmental struggles over provincially-owned wildlands. The AWL persuaded the government to adopt more protectionist policies for Algonquin, Lake Superior and Killarney parks. Preservationist victories included a ban on logging in Quetico Park (1971), and the reclassification of both Quetico and Killarney as primitive parks (1973). After 1973, both preservationists and civil servants planned a system of provincial wilderness parks.

abstract: Doctor of Philosophy (PhD)


title: Biosynthesis, Processing and Intracellular Transport of Herpes Simplex Virus Glycoproteins

contributor:
Ghosh, Hara P.
Biochemistry

subject: Biochemistry Biochemistry

abstract:
The work in this thesis is directed towards a better understanding of herpes simplex virus (HSV) glycoprotein biogenesis and structure-function relationship.

The synthesis and post-translational maturation of HSV type-2 (HSV-2) glycoproteins were studied using an ionophore, monensin. Monensin, by blocking Golgi functions, affected the post-translational processing of three of the five HSV-2 glycoproteins. The HSV-2 glycoproteins gC (gC-2), gD (gD-2) and gE (gE-2) synthesized in the presence of monensin contained incompletely processed N-linked glycans, indicating that the final processing steps for these glycoproteins involved the Golgi apparatus. The processing of N-linked oligosaccharide chains of gB-2 and gG-2 was however found to proceed normally in the presence of monensin. These two glycoproteins had escaped the inhibitory effect of monensin either because of their individual structures or their processing could have involved a pathway different from the rest of the HSV-2 glycoproteins. The intracellular HSV-2 population formed in the presence of monensin contained fully processed gB-2 and gG-2 along with the immature forms of gC-2, gD-2 and gE-2. On the other hand, the extracellular population of HSV-2 was found to contain only fully processed gG-2 in the presence of monensin. This suggested that gG-2 might be transported to the plasma membrane by a yet different pathway and in the presence of monensin, envelopment of HSV-2 can occur at the regions of plasma membrane modified by the insertion of gG-2. Monensin was found to markedly decrease the infectivity of HSV-2 without affecting the yield of the virus particles to the same extent. These findings, together with the processing data indicated differences in the maturation of the glycoproteins of HSV-1 and HSV-2.

The herpes virus qlycoproteins are known to be secreted from the infected cells. Studies with HSV-2 infected cells demonstrated that out of five glycoproteins (gB-2, gC-2, gD-2, gE-2 ,and gG~2) specified by HSV-2, gG-2 is the major glycoprotein secreted into the medium. The size of the secreted form of gG-2 was identical to its intracellular fully processed form. Partial peptide analysis for the intracellular and the secreted gG-2 showed similar patterns, indicating the identity of the two proteins. The data weaken the possibility of removal of the membrane anchoring domain of gG-2 as a cause for its secretion. Though gB-2 and gD-2 were not found to be secreted from the HSV-2 infected cells, monoclonal antibodies, immunoprecipitated the faster migrating forms of gC-2 and gE-2 from the medium. Unlike gG-2, the decrease in molecular weight of the secreted forms of gC-2 and gE-2 suggested that these two HSV-2 glycoproteins can be secreted following proteolytic removal of their membrane anchoring domains. Therefore, as with the post-translational processing mechanisms, it is possible that different mechanisms are involved for the secretion of HSV-2 glycoproteins.

Genes for some HSV-1 glycoporoteins were well characterized and therefore to study the role of HSV glycoproteins in directing the virus to its site of envelopment (inner nuclear membrane), one of the HSV-1 glycoproteins, gC-1, was expressed in mammalian cells using eukaryotic expressions vectors. The glycoprotein was expressed transiently in COS-1 cells under the control of adenovirus major late promoter (Ad MLP). The glycoprotein was found to be properly processed and glycosylated in the COS-1 cells following transfection. As in the HSV-1 infected cells, the transfected COS-1 cells secreted gC-1 containing both the N- and O-linked oligosaccharide chains. The sizes of the intracellular and secreted gC-1 were found to be identical.

Using a different expression plasmid containing mouse wild type dihydrofolate reductase (dhfr) gene as the selectable marker, Chinese hamster ovary (CHO) cell lines constitutively expressing and secreting properly processed gC-1 were established. The glycoprotein was found to be distributed in the nuclear membrane as well as in the cytoplasm of the cells expressing it. As was found in the HSV-1 infected cells, gC-1 in the COS-1 and the CHO cells was found to be present on the cell surface. This indicated that the systems established for expressing gC-1 in the absence of any other HSV-1 proteins synthesize, process and localize gC-1 in a manner similar to the HSV-1 infected cells.

Following this, recombinant retroviruses were generated containing gC-1 integrated in the genome. Transformed Ψ-2 cell lines were generated that constitutively produce the gC-1 containing recombinant retroviruses. Upon infecting 3T3 cells with these recombinant retroviruses permanent lines of cells were generated that constitutively express and secrete gC-1. Unlike the gC-1 producing CHO cells, these cells are permissive to HSV infection. The glycosylation and localization of gC-1 in these 3T3 cells were identical to those found in the H5V-1 infected cells.

Finally, the above-mentioned system for expressing gC-1 in COS-1 cells was utilized for preliminary identification of domains of gC-1 containing signals for secretion and nuclear localization. The approach involved construction of hybrid glycoprotein genes (a) replacing carboxy terminal region of gC-1 with that of vesicular stomatitis virus (VSV) glycoprotein G and (b) replacing the carboxy terminal amino acids of a transmembrane HSV-1 glycoprotein, gB-1, with that of gC-1. The transient expression of these hybrid glycoproteins in COS-1 cells under the control of Ad MLP led to some preliminary but significant observations. The carboxy terminal sequences of VSV G was found to affect the intracellular localization of the hybrid glycoprotein gC₁G. In contrast to gC-1, which was distributed primarily at the nuclear membrane, gC₁G was found to be localized at the region which could be suggested to correspond to the endoplasmic reticulum (ER) and Golgi apparatus. The difference in the intracellular localization patterns of these two glycoproteins suggested that the nuclear localization signal of gC-1 might be present within its carboxy terminal region that was replaced by VSV G.

The other hybrid glycoprotein, gBgC, was found to be localized at the nuclear membrane indicating that the nuclear localization signal thought to be present in the C-terminal part of gB-1 can be replaced by that of gC-1. In addition secretion of this hybrid glycoprotein also suggested that the carboxy terminal amino acid sequences of gC-1 present in this hybrid glycoprotein could contain the information required for its secretion.

abstract: Doctor of Philosophy (PhD)


title: 'Person' in Medical Ethics

contributor:
Waluchow, W.J.
Philosophy

subject: Philosophy Philosophy

abstract:
A conception of person frequently appears in the literature of medical ethics. This thesis will explore 'person' as it appears in this context. My position is that there are such individuals as persons. Scientific and psychological investigation of persons as a kind will provide knowledge about what they are and how they might be harmed. Once we understand that persons are whole beings - gestalts - distinct from, yet at the same time within, a social context, and are metaphysical entities rather than moral constructs, some roadblocks to achievement of the following may be removed: agreement about the nature of persons, subsequent maximization of promotion of their best interests, and just consideration of the moral status of others who are not persons, or whose personhood is indeterminable.

This knowledge is significant for medical ethics. Knowledge of the impending loss of their personhood is a source of suffering for some patients. Physicians must understand that many of their patients are persons, and get to know them as individual persons in order to promote their health and well-being. For this reason, good communication between physician and patient, including the process of obtaining valid consent, is essential.

The role 'person' plays in its familiar context of the issues of abortion and euthanasia will be seen to be inappropriate. Basing the permissibility of abortion on the non-personhood of the fetus is a mistake. It has led to the ill-fated attempts to specify essential characteristics and criteria of persons, and to the obsession with the right to life. This has deflected attention from the more meaningful sense of person, from which more positive and productive obligations may be drawn.

abstract: Doctor of Philosophy (PhD)


title: The Forebrain Taste System: An Examination of the Effects of Stria Terminalis Knife-Cuts on Feeding Behaviour

contributor:
Weingarten, H.P.
Psychology

subject: Psychology Psychology

abstract:
Studies examining the etiology of obesity often focus on the relationship between taste, overeating, and the development of obesity. One animal model often used to study obesity, rats with lesions of the ventromedial hypothalamus (VMH), is popular because the degree of overeating and obesity in that animal is particularly sensitive to the taste qualities of the food the rat eats. The exaggerated sensitivity to taste in VMH rats is termed "finickiness" and is thought to contribute to the hyperphagia and obesity of this animal. The present thesis sought to identify the anatomical locus mediating finickiness. The specific hypothesis examined was that interruption of the stria terminalis (ST), a prominent component of the forebrain taste system and a fibre system destroyed in the typical VMH lesion, produces the finickiness characteristic of the VMH syndrome.

A sham feeding paradigm was used to assess finickiness, because sham feeding allows one to measure the extent to which palatability drives feeding. I found that using sham feeding as an index, rats with ST knife-cuts were as finicky as VMH lesioned rats when consuming either sweet sucrose solutions or quinine-adulterated sucrose solutions. However, the degree of finickiness in rats with combined VMH and ST damage was equivalent to the additive effects of VMH and ST damage alone. These results lead to the conclusion that ST damage was not the locus of VMH lesion-induced finickiness.

Nevertheless, ST knife-cuts did alter feeding; specifically ST knife-cuts produced rats which showed as much of a disturbance of sham feeding as VMH rats. Experiments 2 and 3 investigated whether the overeating of ST animals would generalize to situations when ST rats real feed. Results showed that ST rats ate normal amounts when real feeding, even though VMH rats remained hyperphagic. Thus postingestive signals from the gut, which are activated during real feeding, were sufficient to block or remove the feeding disturbance produced by interruption of the ST. However, signals from food in the gut were insufficient to block the feeding disturbance produced by VMH lesions.

Two more experiments were conducted to determine why the hyperphagia of the ST rat during sham feeding did not generalize to real feeding. Since sham feeding may reflect motivation to eat, it was suggested that the hyperphagia of ST rats when sham feeding may reflect an increased motivation. Therefore, ST rats, VMH rats and controls were tested in a conditioned feeding procedure which provides a direct measure of food motivation. Results indicated that neither ST nor VMH rats demonstrated an increased motivation to eat.

Experiment 5 assessed the contribution of postingestive events from the stomach to the behavioural effects noted with ST and VMH damage. Results showed that ST rats emptied a liquid meal from the stomach at the same rate as controls. However, the rate of gastric emptying was accelerated in VMH rats. It was argued that the difference in the rates at which food emptied from the stomach could account for the differences between ST and VMH rats when real feeding in spite the similarities of their behaviour during sham feeding.

abstract: Doctor of Philosophy (PhD)


title: Hebrew Style and Narrative Sequence in II Samuel i-vii

contributor:
Combs, A.E.
Religious Studies

subject: Religion Religion

abstract: II samuel i-vii is the story of David's accession to the throne after the death of King Saul. Numerous studies of these chapters have concluded that particular aspects of style are evidence 1) that the narrative is a combination of several originally distinct sources, 2) that these sources were edited at a later date to form larger narrative sequences, 3) that the historical David is different than the David depicted in the narrative and 4) that the narrative is sufficiently disunified so that it cannot be read as a sequence of events which culminate in II Samuel vii. The purpose of this dissertation is to argue that the aspects of style used to justify these various conclusions can be more adequately understood as purposeful uses of the Hebrew language for the creation of a narrative. When the details of style are rightly understood, the chapters can and should be read as a coherent sequence of events. The purpose of this story is to depict the actions of several individuals, but David in particular, from a time shortly after the death of Saul to the point at which God makes several promises to David in II Samuel vii. The depiction of the actions of various individuals reveals a richness and complexity of motives, and this complexity is exemplified in the person of David as well. However, the story also represents David as being guided by 1) restraint in response to the house of Saul because Saul had been the anointed of the Lord, 2) a desire to unify both Judah and Israel as a political and religious entity, and 3) a willingness either to consult the ways of God prior to his actions or to conform to God's direction when necessary. David is sufficiently obedient to the stipulations of God in these chapters that God's original anointing of David as king is brought to completion and God makes several new and generous promises to him for the future. The dissertation is divided into two parts. Part I is a review of the most important previous studies on or relating to II Samuel i-vii. In this section I note in detail the stylistic characteristics which are used for the justification of the various readings of the passages. Part II is an inquiry into the style of each of the chapters. This section involves an evaluation of the accounts of style given in Part I as well as a determination of the purposes of other aspects of style of the chapter not yet adequately appreciated. Part II presents the ways in which the Hebrew style of the narrative functions purposefully in the creation of a unified and forceful depiction of this portion of David's life.

abstract: Doctor of Philosophy (PhD)


title: Developing bone collagen stable hydrogen isotope analyses for paleoclimate research and enhancing interpretations with bone carbon, nitrogen and oxygen isotopes

contributor:
Schwarcz, Henry P.
Geology

subject: Geology Geology

abstract: The hydrogen isotopic ratio δD of rain is known to vary according to climate and temperature. The hydrogen in plant tissue reflects both δD of rain and daytime relative humidity (RH) during the growing season. Since tissue from a herbivorous animal records the δD value of the plants in their diets, δD of herbivore bone collagen should ultimately reflect growing season δD of rain, and to a lesser extent, RH. Therefore, the measurement of δD of non-migratory herbivore bone collagen could have considerable potential for monitoring changes in climate through time and thus prove to be a valuable paleoclimatic tool. In this study, methods for analyzing bone collagen for δD were tested and a means for correcting results for hydrogen exchange was devised. It was found that the δD of bone collagen of North American white tailed deer does indeed reflect both growing season rain δD and RH. With correction for the effects of RH the relationship of bone δD versus summer rain δD has a slope of 1.0 indicating a simple relationship and no unexplained sources of bias. It was also found that δ¹⁵N can be used to correct for the effects of RH so that bone δD can be used to estimate rain δD with good accuracy. The rain δD can then be used to estimate temperature. It was further found that relative humidity can be estimated using both bone collagen δD and bone phosphate δ¹⁸O. Additional work found that the δ¹⁵N of bone collagen of animals consuming some C₄ plants is related to local amount of precipitation whereas no such relationship exists for animals consuming only C₃ plants. δ¹⁵N and δ¹³C were also found to vary considerably across North America which could complicate their interpretation in paleodietary studies.

abstract: Doctor of Philosophy (PhD)


title: Design of Linear Array Geometry for High Resolution Array Processing

contributor:
Wong, Kon Max
Reilly, James P.
Electrical and Computer Engineering

abstract:
The linear array is one of the most important types of multi-element sensor arrays, being extensively used in radar, sonar, telecommunications, radio astronomy and medical imaging systems. Traditionally, the array assumes uniform geometry with an inter-sensor spacing of λ/2, which limits resolvability because of the fixed aperture. Since the 1950's, much work has been done on designing nonuniform arrays with focus on conventional beamforming techniques. One of the typical results is the Minimum Redundancy (MR) arrays which provide improved performance over the uniform array.

In this thesis, this issue is re-investigated from the viewpoint of high resolution array processing. A new criterion (called DOBC), based on D-Optimality, is developed, which yields a new array geometry by minimizing a measure of joint estimation error with respect to the array geometry parameters. The sensor gain and phase calibration errors and their effects on high resolution array signal processing are also examined, and formulae are developed to evaluate such effects.

In addition, the Modified Forward-Backward Linear Prediction (MFBLP) method is modified to substantially improve the low SNR performance without increase in computational load. A form of Cramer-Rao lower bound (CRLB) is derived for a reduced model which facilitates performance comparisons in directions of arrival (DOA) estimation.

Computer experiments are conducted to verify our analysis. We conclude that (1) the DOBC design outperforms the conventional uniform array and the MR array; (2) the formulae developed predict very well the behaviour of high resolution algorithms in the presence or absence of calibration errors. The design criterion and formulae can be used by the system designer to design a new array geometry given the performance requirement and hardware specifications, to evaluate the expected performance of an array, given information about hardware specifications, or to develop hardware specifications given the performance requirement.

abstract: Doctor of Philosophy (PhD)