title: Primary Health Care in a Developing Economy: Issues of Job Autonomy, Resources, Quality of Care at the District Level in Zimbabwe

contributor:
Richardson, Jack R.
Sociology

subject: Sociology Sociology

abstract:
Primary Health Care (PHC) is a structural expression of an alternative form of health-care provision whose central philosophy is equity. Since the appearence of this institution on the scene in the late 1970s, numerous developing countries have embraced its tenets in a bid to either replace or counteract the curative approach characteristic of Western biomedicine with varying degrees of success. Concomitant with this is the proliferation of studies, most of which have focused on: the cultural acceptability of PHC technologies; the inequitable distribution of health resources; accessibility of health care facilities. etc. - all of which are germane and laudable attempts to make health a basic human right. However, such research foci neglect some organisational structures upon which the effectiveness of PHC programmes is contingent. Furthermore, the personal experiences of both providers and consumers are often neglected.

The purpose of this exploratory and qualitative study is to investigate the relationship between job autonomy/participation in policy decision making and (a) the quality of health care provision and (b) the effectiveness of the PHC programme, with burnout and job satisfaction/dissatisfaction as the intermediate variables. Empirical research was undertaken in the district of Mutoko (Zimbabwe), with Mutoko District Hospital as the primary site. Data were collected through unstructured interviews, observation and government records.

Analysis of the data reveals that, apart from those with supervisory and managerial responsibilities, most personnel do not show much desire for greater job autonomy/participation in policy decision making. However, the analysis shows that job autonomy/participation in policy decision making and resources have both a direct and an indirect (through the intermediate variables) effect on the quality of health care and the effectiveness of the PHC programme. Furthermore, the analysis indicates that lack of resources, personnel shortages (which lead to work/role overload) and low salaries are the major causes of job burnout and job dissatisfaction in the district health system.

Analysis of consumers' situations and experiences to determine quality of care suggests that the effectiveness of PHC and the utilisation of health services cannot be simply assumed by encouraging people to use them. Therefore, addressing the major concerns noted above is essential to ensure geographical, economic, intellectual and psychological accessibility and that primary health care services become effective in practice.

abstract: Doctor of Philosophy (PhD)


title: Crossing the Chasm: The Rhetoric of the Ineffable in Margery Kempe and Julian of Norwich

contributor:
Savage, Anne
English

subject:
English Language and Literature
English Language and Literature

abstract:
According to theories of negative theology, God cannot be known at all. The divinity cannot be spoken or written. Thus, the mystical text--a written account of the ineffable, divine encounter--is a contradiction in terms. Through an examination of the works of Margery Kempe and Julian of Norwich, I discuss the contradictions inherent in mystical writing. How do these medieval women write their experiences if they cannot write (or even think) the ineffable? This dissertation focuses on the possibility of representing the apophatic moment of contact with the divinity through the structural movement of rhetorical figures.

Most work on Margery Kempe and Julian of Norwich emphasizes the differences between the two writers and, moreover, focuses on their cataphatic or positive approach to the divinity. Contrary to such studies, this dissertation emphasizes the similarities between the writers in their apophatic or negative understanding of God. This work brings together theories of negative theology with rhetorica~ theory to argue that both ystics structure their texts on paradox and, in the process, create rhetorical icons that gesture toward an unknown, ineffable God. In particular, the rhetorical figures of chiasmus and contentio (especially in relation to the coincidence of opposites) are examined for their ability to represent the paradox associated with the apophatic moment of crossing between the human and the divine.

abstract: Doctor of Philosophy (PhD)


title: Pacemaker Activity and Intercellular Communication in the Intestinal Musculature

contributor:
Huizinga, Jan D.
Electrical and Computer Engineering

subject:
Electrical and Computer Engineering
Electrical and Computer Engineering

abstract:
Knowledge of the origin and characteristics of the intestinal pacemaker activity, and the characteristics of intercellular communication throughout the musculature is instrumental for the understanding of the mechanisms through which gastrointestinal (GI) motility is regulated. This thesis makes a significant contribution to provide electrophysiological and morphological evidence supporting the hypothesis that interstitial cells of Cajal (ICCs) are the Gl pacemaker cells. The pacemaker activity of the GI tract triggers the slow-wave.type action potentials (slow waves) which are coherent with the phasic contractions for facilitating peristaltic movement. Origins of the slow waves at different portions of the GJ tract always coincide with the locations of the ICCs. The objectives of this study were to identify the cellular origin of the pacemaker activity and to thoroughly investigate the mechanism of intercellular communication in the canine colon using electrophysiological and microscopic techniques. The cellular origin of the pacemaker activity was further examined by studying simultaneously the ontogenesis of the pacemaker activity and the ICCs in the neonatal mouse small intestine.

The cellular origin of the pacemaker activity was studied by employing the photodynamic property of methylene blue (Chapter 3). We previously demonstrated that the submuscular ICCs of the canine colon selectively accumulate methylene blue. In this undertaken study, we further illustrated that incubation with 50 μM methylene blue and subsequent intense illumination resulted in abolition of the pacemaker activity. Following methylene blue incubation, intense illumination first changed the mitochondrial conformation in the ICCs from very condensed to orthodox, and progressively imposed more severe damages, such as swollen and ruptured mitochondria, loss of cytoplasmic contrast and detail, and rupture of the plasma membrane. No damage was seen in smooth muscle cells and nerves. The correlation between selective lesioning of ICCs and loss of the pacemaker activity strongly supports that ICCs play an essential role in the generation of the pacemaker activity.

The regulatory mechanism of the pacemaker frequency was investigated with a focus on the effects of cyclopiazonic acid (CPA), a specific inhibitor of the endoplasmic reticulum (ER) Ca²⁺-pump (Chapter 4). CPA dose dependently decreased the pacemaker frequency. Similarly, chelating cytosolic Ca²⁺ with BAPTA also decreased the pacemaker frequency. The pacemaker frequency was also decreased by neomycin (inhibiting inositol 1,4,5-triphosphate (IP₃) synthesis) and caffeine (inhibiting the IP₃-sensitive Ca²⁺ channels in the ER membrane). Electron microscopy showed that the smooth ER forms an extensive network of subsurface cisternae which is closely associated with large areas of the cytoplasmic face of the plasma membrane. These structures were the most extensive in the ICCs, slightly less in branching smooth muscle cells and far less in circular muscle cells. Based on the electrophysiological and morphological observations, we hypothesize that the Ca²⁺ refilling cycle of the IP3-sensitive calcium stores associated with the plasma membrane, determines the frequency of the pacemaker activity generated by the submuscular ICC-smooth-muscle network of the canine colon.

The ontogenesis of the pacemaker activity and the ICCs in the small intestine of neonatal mice was studied to further substantiate the pacemaker role of ICCs (Chapter 5). The pacemaker component of the slow waves was fingerprinted by its resistance to L-type Ca²⁺-channel blockers and sensitivity to cyclopiazonic acid, CPA, (Chapter 4). All isolated musculature of the neonatal mouse small intestine (newborn, unfed-7 days old) spontaneously generated action potentials. The presence of the pacemaker component in different age groups was examined by verapamil, a L-type Ca²⁺ channel blocker, and CPA. In conclusion, electrophysiological and morphological evidences were obtained to demonstrate that both the pacemaker activity and the, ICC network were immature at birth but fully developed in 2 days old neonatal mice.

Communication between the longitudinal and the circular muscle layers are essential for producing co-ordinated motility in the musculature. Through electrophysiological measurements with microelectrodes, the study of neurobiotin spread using confocal microscopy and the investigation of the cellular structure at the electron-microscopic level, the cellular mechanisms of communication between the two muscle layers was studied. We positively demonstrated the existence of low-resistance pathways. We also provided evidence that the ICCs associated with the myenteric plexus facilitated electrotonic coupling between the two muscle layers across the myenteric plexus of the canine colon (Chapter 7).

In the longitudinal muscle layer, no positive evidence for electrical coupling between smooth muscle cells has yet been presented. We thoroughly examined the properties of electrical coupling in the longitudinal muscle layer of the canine colon (Chapter 8). The properties of electrical coupling between longitudinal muscle cells were compared with that between the circular muscle cells. Three electrical coupling parameters were measured: (i) the input resistance, (ii) the space constant (determined by the method developed with a double-electrode technique (Chapter 6)), and (iii) the phase relationship of simultaneously recorded electrical activities. Furthermore, a detailed electron microscopic investigation revealed the absence of gap junctions in the longitudinal muscle layer; whereas, numerous close apposition contacts were observed. These observations put forward the hypothesis that the pathways for electrical coupling between longitudinal muscle cells are consituted by close apposition contacts.

Communication between circular muscle (CM) lamellae is necessary to generate propulsive phasic contractions for facilitating peristalsis along the longitudinal axis of the GI tract. The submuscular ICCs are extensively coupled to the underlying branching smooth muscle (bSM) cells forming an ICC-bSM network covering the entire submucosal surface of the canine colon. There is another ICC network located in the myenteric plexus. The roles of the submuscular ICC-bSM network, the myenteric ICC network and the longitudinal muscle layer in mediating communication across the CM lamellae were studied by simultaneous recordings with surface electrodes using different types of muscle strip preparations (Chapter 9). Electrophysiological evidence demonstrated that, within the pure circular musculature, circular muscle cells were electrically coupled along a CM lamella, oriented circumferentially around the lumen, but electrically insulated across CM lamellae. The submuscular ICC-bSM network, but not the longitudinal muscle nor the myenteric plexus, was shown to be essential for mediating communication between CM lamellae such that co-ordinated motility can be exhibited with neig,hbouring CM lamellae through excitation-contraction coupling.

In summary, employing a number of electrophysiological and microscopic techniques, this dissertation presents novel evidence (i) to substantiate the pacemaker role of ICCs in the GI tract; (ii) to put forward a hypothesis that the pacemaker-frequency regulatory mechanism is synchronized with the ER Ca²⁺ refilling cycle; and, (iii) on the heterogeneity of mechanisms through which intercellular communication occurs along the radial, circumferential and longitudinal axes of the intestinal musculature.

abstract: Doctor of Philosophy (PhD)


title: Ethnic Earnings Inequality in Canada

contributor:
Denton, Margaret
Fox, John
Sociology

subject: Sociology Sociology

abstract: Evidence in the literature and from the 1991 Census indicates that there has been significant educational and occupational mobility among Canadian ethnic groups over the past decades. The extent of ethnic mobility in earnings, however, has been quite different from that in education and occupation. The present study re-examines the issue of ethnic and racial inequalities in earnings and evaluates two contending views, namely, the Vertical Mosaic thesis, which emphasizes ethnicity as a fundamental basis of social stratification in Canada, and the New Mosaic thesis, which stresses ethnic mobility in socioeconomic status. Based on the Public Use Microdata File on Individuals drawn from the 1991 Census of Canada, it is found that, while earnings differences were not profound either among European groups or among visible minorities, substantial disparities existed between these two broad categories to the disadvantage of visible minorities. It is therefore argued that neither the Vertical Mosaic thesis nor the New Mosaic perspective is adequate in describing current Canadian society: the Canadian Mosaic is still vertical, but race has replaced ethnicity as a fundamental basis of stratification in earnings. In a regression model estimating the extent of "direct" pay discrimination, or "unequal pay for equal work," ethnic differences in a number of earnings-related variables were statistically controlled. Substantial earnings differentials were again found, though to a lesser extent, largely between European groups and visible minorities. Such discrimination was further demonstrated when ethnic earnings differentials were estimated within educational and occupational categories and within immigrant cohorts. It is evident that equal work was not paid equally and that racial discrimination was still a significant phenomenon in the Canadian labour market in the early 1990s.

abstract: Doctor of Philosophy (PhD)


title: Detection of Signals in Chaos

contributor:
Haykin, Simon
Electrical and Computer Engineering

abstract:
A new method for the detection of signals in "noise", which is based on the premise that the "noise" is chaotic with at least one positive Lyapunov exponent, is presented. The method is naturally rooted in nonlinear dynamical systems, and relies on neural networks for its implementation.

We first present a theoretical basis for methods of modeling the underlying dynamics of a chaotic system using a time series. The subject matter selected for this part of the thesis is written with emphasis on experimental studies of chaos. Specifically, we discuss the issues involved in the reconstruction of chaotic dynamics, attractor dimensions, and Lyapunov exponents. We describe procedures for the estimation of the correlation dimension and the Lyapunov exponents. The method of false nearest neighbors analysis fur finding the minimum embedding dimension is described. The need for an adequate data length is stressed.

In the second part of the thesis we apply the chaos-based method to the radar detection of a small target in sea clutter. To justify the applicability of the new method to this problem, we clearly need to show in a convincing way that sea clutter is indeed the result of a chaotic dynamical system. We do this by presenting the results of a detailed experimental study using surface-truthed real-life data collected by means of an instrument quality radar at different geographic locations. Specifically, we show that (1) sea clutter has a finite correlation dimension, (2) the largest Lyapunov exponent of sea clutter is positive, and (3) sea clutter is locally predictable. Most importantly, we show that both the correlation dimension and the largest Lyapunov exponent are essentially invariant to the choice of radar signal component used to construct the time series, and that the correlation dimension and Lyapunov exponent do not appear to change appreciably with sea state or with geographic locations. These results suggest that there may exist universal chaotic structure responsible for the generation of sea clutter. Perhaps the most dramatic result presented in the thesis is the fact that this prior information (i.e., the knowledge that sea clutter exhibits chaotic behavior) can be exploited to build a chaos-based detettor operating on amplitude information only (as in a noncoherent marine radar), realizing a performance comparable to that of a "conventional" receiver using coherent radar data (i.e., both amplitude and phase). This result points to the potential of trading off sophisticated but inexpensive computer software for expensive microwave hardware. Lastly, we show experimentally that a chaos-based coherent detector can provide a further improvement in radar detection performance.

abstract: Doctor of Philosophy (PhD)


title: Automated Tool Condition Monitoring in Machining Using Fuzzy Neural Networks

contributor:
Elbestawi, M.A.
Mechanical Engineering

subject:
Mechanical Engineering
Mechanical Engineering

abstract:
A new approach for automated tool condition monitoring in machining by using fuzzy neural networks is proposed. The Multiple Principal Component (MPC) fuzzy neural networks are built based on three major components of soft computation, namely fuzzy logic, neural networks, and probability reasoning.

The system architecture is a partially connected neural network with fuzzy classification at neurons and fuzzy membership grades for interconnections. Principal component analyses in multiple directions are implemented tor the feature extraction and the "maximum partition". The partitions of the learning samples are based on the distributions of the monitoring indices in the principal component directions. A fuzzy membership function is used to measure uncertainties in the sampled data and to form "soft boundaries" between the classes. A processing clement in the network is connected to others through the fuzzy membership grades and other information available. The partial connections make short training times and short routines in classifications.

Three major issues in developing the MPC fuzzy neural networks are supervised classification, unsupervised classification and knowledge updating. The system obtains the knowledge about classifications by learning. The learning samples are obtained from cutting tests performed through a reasonable range of cutting conditions.

Several sensors are used for monitoring feature extraction. The signals from different types of sensors at different locations insure that the most significant information about the changes in tool conditions is collected. Metal cutting mechanics are first considered for the sensor selection and the sensor allocation. The measured signals are further analyzed and the monitoring features are extracted. These indices are the inputs for the fuzzy neural networks. The tool conditions considered include sharp tool, tool breakage, and a few selected stages of tool wear. The experimental results in turning and drilling have shown good performance of the proposed monitoring system in these tests.

abstract: Doctor of Philosophy (PhD)


title: Experience, Language, and Dialogue in Postmodern Theology: A study of Jürgen Moltmann's Theological Method

contributor:
Robertson, J.C.
Religious Studies

subject: Religion Religion

abstract: This dissertation examines key aspects of Jürgen Moltmann's writings in order to determine the extent to which non-biblical language and experience determine his theology. He employs various hermeneutical frameworks to create a postmodern political theology. This theology is intended to replace the modern subjectivist interpretations of certain biblical themes, such as the eschaton, the crucifixion of Christ, and the relationship between the Father, Son and Holy Spirit. Moltmann draws on a number of sources to help him rearticulate these themes in a way that, he believes, is more meaningful and politically relevant in the modern context. This study of Moltmann's theology was suggested to me by George Lindbeck's model of religion, which I employ as a heuristic device in the analysis of Moltmann's writings. Lindbeck synthesizes the ideas of language philosophers, cultural anthropologists, and narrative theologians to construct, what he calls, a postmodern cultural-linguistic understanding of the relationship between experience and language in religions. This model of religion attempts to show that religious life and experiences are determined by the language of the each tradition. Lindbeck believes that this view of religion has implications for theological method. In the Christian context, he believes that the language contained in the Bible and Christian doctrines should be understood as the source of religious experience. Christian theologians should not, then, base their theologies on extra-biblical descriptions of the nature of religious experience. To do so would be to allow them to eclipse the possible religious experiences generated in genuine attempts to live out the story of the Bible. There are aspects of Moltmann's approach to theology that seem to correspond to Lindbeck's demand that the language of the Christian tradition should be the leading partner in the dialectic between extra-biblical experiences and ideas. But Moltmann's theology seems, in key places, to be more heavily informed by non-biblical interpretive frameworks than permitted by the cultural-linguistic model of religion. I conclude, then, that Moltmann's theological method is not, for the most part, consistent with Lindbeck's recommendations for theological method.

abstract: Doctor of Philosophy (PhD)


title: Regulation of Interleukin-6 and Tumor Necrosis Factor-α in Rat Peritoneal Mast Cells by Lipopolysaccharide, Prostaglandin E₁, Prostaglandin E₂ and Cholera Toxin

contributor:
Marshall, Jean S.
Medical Sciences

subject:
Medical Sciences
Medical Sciences

abstract:
The mast cell has been implicated as an initiating cell in the immediate responses to allergen challenge where preformed mediators such as histamine play an important role. However, the role of mast cells is less well understood in severe allergic disorders such as asthma where chronic inflammatory changes are resent. Results presented in this thesis demonstrate that freshly isolated and highly purified rat peritoneal mast cells can release IL-6 without any necessity for histamine release. These observations were determined with the use of bacterial products such as LPS and CT which significantly enhanced IL-6 production in our system.

Prostanoids of the E family (PGE₁ and PGE₂) were also used as stimulating agents which may also participate in inflammation. We observed that these prostaglandins selectively enhanced IL-6 production while TNF-α synthesis was significantly inhibited CT was observed to have very similar effects to PGE₁ on mast cells . These findings illustrate the potential role that mast cells may have during chronic inflammation and infectious disease.

abstract: Doctor of Philosophy (PhD)


title: Resource allocation in giant "Supermice" genetically engineered with extra rat growth hormone genes

contributor:
Rollo, David C.
Biology

subject: Biology Biology

abstract:
Genetically engineered "Supermice" harbouring multiple copies of rat growth hormone genes, attain adult body sizes almost twice that of normal mice. To determine how transgenic mice adjust resource acquisition and processing with elevated growth, dry mass budgets were conducted on Supermice (strain Tg[MT-1, rGH], Bri2) and normal Mus musculus. Rates of growth, consumption, faecal deposition, digestive assimilation, respiration, and production efficiencies were compared for both early and late growth intervals.

Younger, faster-growing mice (25-40 days old) displayed higher rates and production efficiencies than those documented for older, slower-growing mice (47-62 days old). Swprisingly, Supermice never exhibited growth rates greater than those displayed by the most rapidly growing normal controls. For transgenic animals, larger body sizes were achieved by maintaining increased growth rates into later ages. Dry mass budgets revealed that Supermice failed to alter mass-specific feeding rates to compensate for their increased growth demands, but production efficiencies were greatly enhanced instead. Superior conversion of assimilated food into biomass was obtained by diverting resources from other behavioural, reproductive, and longevity assurance systems. Shortcomings prevalent in Supermice (lethargy, reduced fecundity, decreased longevity, disturbed metabolism, and various pathological problems) have been similarly expressed in genetically engineered livestock and other organisms conforming to acromegalic states including humans and large breeds of dogs. Thus, transgenic GH mice may offer practical insights for agricultural and medical applications.

Trade-offs in the Supermouse are apparent in their "transgenic correlation structure" which represents a new alternative for testing and clarifying facets of life-history theory. It is concluded that production efficiency is a key component linking life-history features in Mus musculus, and may be a fundamental element in both environmental adjustments and evolutionary changes.

abstract: Doctor of Philosophy (PhD)


title: Structure of Superdeformed Bands Near the N=80 Shell Gap

contributor:
Waddington, J.C.
Physics

subject: Physics Physics

abstract:
As part of a systematic survey of superdeformation in nuclei in the vicinity of ¹⁴³Eu, six superdeformed bands in ¹⁴²Sm, ¹⁴²Eu and ¹⁴⁴Eu have been studied by their Υ-ray decay following heavy-ion fusion-evaporation reactions. All of these bands are based on a "second minimum" shell gap associated with the superdeformed (2:1 prolate ellipsoid of rotation) nuclear shape at neutron number N=80 and proton number Z=63. The first band in ¹⁴²Sm and the band in ¹⁴²Eu have been studied with the 8π spectrometer, while the bands in ¹⁴⁴Eu and the excited band in ¹⁴²Sm have been discovered with the GAMMASPHERE array. The Υ-ray decays of these superdeformed structures are compared to collective rotational models, and specifically to state-of-the-art Cranked Shell Model (CSM) calculations for Nilsson, Woods-Saxon, and Hartree-Fock models of the nuclear potential. The predicted roles of specific orbitals in the A~140 mass region are compared to quantities derived from the experiments and where possible, configurations with respect to an ¹⁴³Eu core are proposed.

The first ¹⁴²Sm band consists of 19 Υ-ray transitions with an intensity of 0.5% of the reaction channel, and its behaviour is best described in the calculations as an ¹⁴³Eu superdeformed core with a hole in an Nosc=5 proton orbital. The second excited band consists of 15 transitions with an intensity ~ 20% that of the first band, of which the transitions above ~ 1 MeV are identical in energy to those in a ¹⁴⁶Gd band. This new band, which represents the second example of a two-proton, two-neutron identical bands pair, is most likely a ¹⁴⁶Gd superdeformed core with four holes in low Nosc orbitals. Structures based on simple excitations of the proton hole of the first band likely comprise a quasi-continuum ridge structure.

The ¹⁴²Eu band has 15 transitions and an intensity of 1.2%. The detailed behavior of this band suggests that its configuration is an Nosc=5 neutron hole in the ¹⁴³Eu core. Such a configuration is not predicted to be energetically favourable.

The three ¹⁴⁴Eu bands all have population intensities of < 0.2 % relative to the reaction cross-section. Two of the ¹⁴⁴Eu bands, with 17 and 18 transitions respectively, are quite likely Nosc=6 neutron particle states coupled to the ¹⁴³Eu core. The behavior of the third band indicates occupation of an Nosc=7 neutron intruder which does not influence the shape of the ¹⁴³Eu core.

abstract: Doctor of Philosophy (PhD)


title: Emulsion Polymerization Kinetics with Crosslinking

contributor:
Hamielec, A.E.
Chemical Engineering

subject:
Chemical Engineering
Chemical Engineering

abstract:
Emulsion polymerization of vinyl/ldivinyl monomers may result in crosslinked polymers and lead to peculiar characteristics for the kinetics and network structure. Herein is provided a comprehensive study including both extensive experimentation and computer modeling with the aim of elucidating the effects of crosslinking on emulsion polymerization kinetics.

The model monomer system chosen for the present study was methyl methacrylate (MMA) and ethylene glycol dimethacrylate (EGDMA) as the comonomer and crosslinker. The polymerization temperature was 50°C. Potassium persulfute (KPS) was the initiator. Sodium dodecyl sulphate (SDS) as emulsifier was used below and above the critical micelle concentration(CMC).

The monomer conversion, polymer particle number and size development, swellability of crosslinked polymer particles, pendant double bond (PDB) conversion, the glass transition temperature (Tg) and the internal heterogeneity in polymer particles were measured as a function of time in a batch reactor. It has been found that EGDMA level in the monomer feed and the initiator concentration have a pronounced effect on the behavior of the polymerization process. The experimental responses were very different when polymerizations were done below and above the critical micelle concentration.

ESR was used to measure the dramatic radical concentration increase which is particularly great at higher levels of crosslinking. Time profiles of propagating radical concentrations have two regions. A relatively constant radical concentration region coupled with high rates of monomer conversion and polymer particle generation and a dramatic radical concentration increase coupled with a level off in monomer conversion and polymer particle concentration. These observations suggest that a trapping of radicals within the crosslinked polymer network occurs during emulsion polymerization an this is further confirmed by ESR testing of solid polymer samples coupled with DSC testing of residual PDB in the same samples.

The second part of this study features kinetic modeling and the simulation of the kinetic equations by the Monte-Carlo method. An existing kinetic model for crosslinking density distribution has been revised to acCOWlt for the shielding effect on pendant double bond reactivity. In addition, a stochastic Monte-Carlo simulation algorithm for emulsion polymerization has been developed. After basic testing, the program has been applied to emulsion homopolymerization with long chain branching and copolymerization with or without branching/crosslinking. Calculated results clearly reflect the kinetic phenomena when crosslinking is relevant In the present study, Monte-Carlo simulation has been used to simulate kinetic behavior in stage II where polymer particle concentration is constant. However, the algorithm can readily be extended to include the nucleation period (stage I) and the finishing stage (stage III) and to consider a host of kinetic event combinations provided that the proper kinetic expressions, constraints and criteria conditions are available.

abstract: Doctor of Philosophy (PhD)


title: Correction and Enhancement of Landsat Data For Hudson Bay Lowlands Vegetation

contributor:
Howarth, P. J.
Geography

subject: Geography Geography

abstract: The effects of solar and atmospheric corrections, and the linear contrast stretch, band ratioing and video filtering enhancements on Landsat data were studied for two areas of northern Canada. Studies were carried out using computer compatible tapes on an image analysis system and both numerical and visual evaluations were made. It was determined that solar and atmospheric corrections may not be sufficient to standardize Landsat data between different dates of imagery. In contrast, however, it was found that the linear contrast stretch and the band ratioing enhancements effectively emphasized the ground surface patterns. The video filtering enhancement was insufficient to enhance the image.

abstract: Master of Science (MS)


title: A Space-Time Reactor Simulation

contributor:
Garland, Doctor W.J.
Engineering Physics

subject: Engineering Physics Engineering

abstract:
Exploration of the processes involved in fission reactor dynamics and the solution techniques required for such a problem is the objective of this research. Reactor behavior is governed by neutron kinetics and thermalhydraulics, and the spatial and temporal interaction of the two processes. The analytical solution of such a problem in all but the simplest of cases, is impossible. Hence, numerical methods are required. Simulation software is developed to model the space-time behavior of nuclear systems and this software is then used to study the behavior of these systems. This investigation involves the mathematical modeling and numerical simulation of the phenomena encountered. The desired result is an accurate depiction of reactor behavior.

The majority of contemporary simulations involve only a loose coupling between the neutronics and thermalhydraulics both spatially and temporally. It is more expedient to solve reactor kinetics and thermalhydrauluc simulation problems sepatately. A point kinetics model is frequently added to thermalhydraulic simulation to model reactor power but this would ignore spatial effects. The simultation developed here is a space-time reactor kinetics simulation with an integral thermalhydraulics module. This integral thermalhydraulics module provides for good spatial and temporal coupling of the two processes and is the primary distinguishing feature of the software.

The rate form of the equation of state is used in the solution of the pressure field in the thermalhydraulic problem. A rate equation is better suited to the problem procedure for the thermalhydraulics than the use of an equation state.

Efforts were made to take advantage of the structure of the problem to reduce computational effort. Partitioned matrices are used in the time integration of both the neutron kinetics and thermalhydraulics. This helped reduce computational effort by facilitating the use of routines that exploit the sparsity of the Jacobian. A second order semi-implicit Runge-Kutta method is used for the time integration of the neutron kinetics problem. This method requires matrix inversion but is a robust and reliable method for solving a stiff system of ordinary differential equations.

The two component modules of the software, the neutronics and the thermalhydraulics, were developed and tested separately before they were integrated. The results of these tests and simulations using the completed software are given.

abstract: Doctor of Philosophy (PhD)


title: In Vivo and In Vitro Regulation of the IL-6 subfamily of Cytokine Receptors in the Liver

contributor:
Gauldie, Jack
Medical Sciences

subject:
Medical Sciences
Medical Sciences

abstract:
Interleukin 6 (IL-6) is a pleotropic cytokine that has many important physiological roles during inflammation. One function is the regulation of the acute phase response of the liver. In order to understand the role of IL-6 as an inflammatory mediator in the acute phase response, it was necessary to study the effect that this molecule had on the regulation of its own receptors, IL-6 receptor (IL-6R, gp80 or α-receptor), and signal transducing protein, gp 130, both in vivo and in vitro.

To investigate the role that IL-6 and corticosterone play in the acute phase response and receptor regulation, we examined serum IL-6 levels, serum corticosterone levels, acute phase protein levels, and the expression of hepatic IL-6R (gp80) and gp 130 mRNA levels, in three different models of acute inflammation. Rats were treated with either Freund's complete adjuvant (FA) via intraperitoneal injection, LPS via intravenous injection, or turpentine via subcutaneous injection. All three models showed increased levels of serum IL-6 activity with LPS-treated rats inducing the quickest and greatest response (>100 ng/ml within 3h). Serum corticosterone levels increased by 3h after all treatments, and serum levels of acute phase proteins were detected within 12-24h. The expression of the IL-6R (gp80) mRNA increased as early as 3h after treatment and mRNA levels began to decline by 6-12 h. The gp 130 mRNA levels increased 2-3 fold within 24h, and the time of maximum increase differed depending on the treatment that the rat received.

Another cytokine, Leukemia Inhibitory Factor (LIF), and IL-6 share many functions in vitro, and this redundancy is thought to occur as a result of their two alpha receptors, LIF-R and lL-6R, respectively, interacting with the same signal transducing molecule, gp 130. We examined the increase of LIF-RmRNA levels in the three models of acute inflammation to determine the role of LIF during the acute phase response in comparison to IL-6. We found a maximum 2-3 fold increase in mRNA levels in comparison to controls. Maximum LIF-R mRNA levels varied depending on the type of treatment the rats received.

Overall analysis of all mRNA levels studied, showed that maximum IL-6R (gp80), gp 130, LIF-R and Cysteine Proteinase Inhibitor (CPI-an acute phase protein whose expression is regulated by IL-6) mRNA levels peaked at different times depending on the type of acute inflammation induced. Although IL-6R mRNA levels reached maximum levels quickly (3-6h) in all three models of acute inflammation, the maximum induction of gp 130 and LIF-R differed depending on the type of treatment the rats received. In all three acute inflammatory models, IL-6R and LlF-R mRNA leveIs did not peak at the same time for any of the treatments given. This suggests that although IL-6 and LIF may have similar functions in vitro, their role in vivo in inflammation is unique. Staggering of maximum LIF-R and IL-6R expression in the liver may ensure that cells are receptive to continual messages to make acute phase proteins.

To further investigate the individual effects of raised corticosterone and 1L-6 on the expression of these receptors, rats were injected with either d examethasone (DEX) or purified recombinant IL-6 (rIL-6) via intraperitoneal injection. Rats injected with rIL-6 showed a dramatic increase in both IL-6R (gp80) and gp 130 mRNA levels, as early as Ih after treatment. Dexamethasone had a significant, but less dramatic effect, on IL-6R (gp80) mRNA levels and no effect on gp 130 message. An acute phase protein response was only seen when rats were injected with rIL-6 and not DEX. Neither rIL-6 or DEX treated rats-had any effect on LIF-R mRNA levels.

To continue these studies, we investigated the long term in vivo effects of prolonged exposure to purified rIL-6 on the expression of these hepatic cytokine receptors. Repeated injections of rIL-6 did not cause decreased mRNA levels, instead increased 1L-6R (gp80), gp 130, and CPI mRNA levels (2-3 fold) were seen. Serum CPI protein levels increased gradually over a nine day period from 1.4 mg/ml to 5.8 mg/ml. LIF-R mRNA levels remained unaffected by the repeated injections of rIL-6.

The steady-state mRNA levels of the interleukin-6 receptor (IL-6R, gp80) and its signal transducing molecule, gp130, were examined in the rat hepatoma cell line, H-35, stimulated by cytokines IL-6, IL-1, Oncostatin M, and/or DEX. In contrast to our in vivo findings, in vitro DEX seemed to be the major stimulator of IL-6R mRNA expression, whereas IL-6 seemed to have little effect on the expression of its own receptor mRNA levels. However, the presence of other cytokines also influenced the corticosteroid (dexamethasone-DEX) mediated stimulation of IL-6R expression. Oncostatin M, a third cytokine related to IL-6, stimulated lL-6R mRNA levels, and this stimulation was additive with the DEX-mediated stimulation of IL-6R mRNA levels. In contrast, Interleukin 1 (IL-1) inhibited the DEX-mediated stimulation of IL-6R mRNA. At the same time, lL-1 also stimulated the presence of a second smaller mRNA transcript. This mRNA species contained the extracellular domain but lacked both the transmembrane and cytoplasmic domains of the IL-6R, suggesting alternate splicing, possibly coding for a soluble form ofgp80.

The expression of the gp130 molecule was not regulated to any major extent in vitro, and cytokines IL-6, Oncostatin M, and IL-1 all stimulated the expression of the signal transducing molecule, gp130, approximately 2 fold.

Cysteine Proteinase Inhibitor mRNA and protein levels were elevated by combinations of cytokines: IL-6+DEX, IL-6+IL-1+DEX, OSM, OSM+DEX. However, IL-1 again seemed to inhibit the IL-6+DEX mediated stimulation of CPI mRNA, possibly through inhibition of IL-6R expression and induction of a possible soluble form of the receptor.

This study shows that the combination of cytokines and hormones that interact with the hepatocyte and in turn, regulate the expression of these different receptors is very complex. In vitro, we demonstrated that both IL-1 and Oncostatin M are involved in the regulation of the IL-6 receptor complex, and that different combinations of cytokines can affect the complexity and magnitude of the hepatic acute phase response. In vivo, we demonstrated that depending on the type of acute inflammation induced, that a variety of combinations of cytokines and hormones are released, and these in tum regulate the diverse receptors on the hepatocyte, resulting in different acute phase response kinetics. Therefore, even though all of these receptors belong to a family and have similar functions, the regulation of these receptors is unique and may lead to altered cell responses in the different models of inflammation.

abstract: Doctor of Philosophy (PhD)


title: Studies in the Representation of Dwarfs in Hellenistic and Roman Art

contributor:
Dunbabin, Katherine M.D.
Classics

subject: Classics Classics

abstract: As individuals who fell outside the prevailing norms of society, dwarfs were often regarded as prodigies in antiquity: living amulets as well as instruments of private and public entertainment. The roles assumed by dwarfs in Hellenistic and Roman society are explored through evaluation of literary and archaeological evidence. Most literary citations point to dwarfs as entertainers for wealthy households and their guests and also for public audiences. A catalogue of bronze and terracotta figures represents musicians, dancers, combatants and athletes. An INTRODUCTION and CHAPTER ONE explain the aims of the thesis; describe limitations posed by the nature of surviving material; and review the modern literature. CHAPTER TWO summarises ancient literary testimony (Greek and Latin terms, and functions and perceptions of dwarfs) as well as relevant archaeological material not included in the catalogue. CHAPTERS THREE, FOUR and FIVE focus on iconography, i.e. details of costumes and associated objects. Further considerations include clinical features of dwarfism (CHAPTER SIX); function and significance (CHAPTER SEVEN); and provenience and dating (CHAPTER EIGHT). Following the CONCLUSION, a CATALOGUE lists and describes 185 objects, each with museum and inventory number, bibliography, and proveniences. The archaeological record, although lacking many monuments of secure provenience and date, indicates the widespread popularity of dwarf representations in Egypt, the Mediterranean and continental Europe. They share some similarities. in style, function and subject matter, with those of classical Greece and pre-Ptolemaic Egypt, but at the same time, living dwarfs must survive in a climate of societal rejection which worsens in Hellenistic and Roman times.

abstract: Doctor of Philosophy (PhD)


title: Cinema as Secular Church: A Phenomenological Typology and Hermeneutics

contributor:
Madison, Gary B.
Philosophy

subject: Philosophy Philosophy

abstract: The central claim of the present thesis is the idea that the film experience for us is the displaced expression of an interest which is fundamentally spiritual. After offering a phenomenological typology of the film experience, the thesis argues that the common denominator of these various types is the desire to touch the wholly other, a peculiarly postmodern variant of a much older desire, the desire to transcend oneself. Postmoderm, secularized man is in fact deeply spiritual and the film experience can be shown to be an increasingly self-conscious, though still sublimated expression of this neeed to transcend the limits of the flesh. What we get in the film experience is a religious smorgasbord, rather than any particular denominational perspective. The modern rise of science and technology as increasingly dependable sources of knowledge about the world, as well as various philosophical attacks which have been levelled at our ability to know the world and ourselves, have contributed to a growing sense of free-floating subjectivity. We no longer know exactly who we are. The vacuum left by the demise of religious authority cannot be filled by scientific/objective knowledge alone. We are in need of spiritual grounding as well, and through its contribution to constructed subjectivity, cinema is ideally suited to fill the void.

abstract: Doctor of Philosophy (PhD)


title: Substituted 2-Aminotetrahydronaphthalenes as Affinity and Photoaffinity Probes for Dopamine Receptors

contributor:
Mishra, R. K.
McCarry, B. E.
Medical Sciences, Neurosciences

subject: Neurology Neurology

abstract:
In the current investigation several biochemical techniques, including solubilization, affinity chromatography and photoaffinity labelling, were used to purify the D-1 dopamine agonist ADTN (2-amino-5, 6-dihydroxy-tetrahydornaphthealene) to be used as affinity and photoaffinity probes was an integral part of this investigation.

Solubilization of the D-1 receptor was achieved with several detergents although cholic acid proved to be the most effective for receptor solubilization prior to affinity chromatography. Using this procedure, yields of solubilized receptors of greater than 30% were consistently obtained.

An affinity chromatography protocol utilizing an ADTN analogue covalently coupled to an affinity matrix was established for cholate-solubilized D-1 receptor. The affinity protocol developed during this investigation purified the D-1 receptor approximately 50-fold, while an average of 8% of the receptors were recovered. These results were superior to any previous literature reports of D-1 receptor purification.

Several photoactive compounds were synthesized and used to crosslink D-1 receptors. One compound in particular, a photoactive derivative of the dopamine against ADRN, proved to be a useful ligand for this purpose. A tritiated derivative of this compound was covalently and specifically incorporated into a protein of M.W. =79kDa. This was the first report that the D-1 receptor had a M.W. of greater than 70kDa as determined by affinity crosslinking. Several other investigators have subsequently confirmed this observation.

Other photoactive compounds radiolablled with 125I were synthesized and examined for activity as D-1 and D-2 receptor probes. These compounds were not as useful as photoaffinity labels for dopamine receptors as had been originally proposed. The compounds did label a 50kDa protein which was determined to be neither the D-1 nor D-2 receptor. This protein (originally designated Apo-50 and later CatNAP) has very interesting properties as it possesses binding activities with several catecholamines which are without precedent in the literature.

abstract: Doctor of Philosophy (PhD)


title: Integrating InP Waveguides: Measuring Processing Stress and Modelling Intersecting Waveguides With Low Crosstalk

contributor:
Jessop, P.E.
Engineering Physics

subject:
Engineering Physics
Engineering Physics

abstract:
Two major problems in InP waveguide design were studied. The first of these is the effect of processing induced stress on the mode of an InP/lnGaAsP waveguide. The stress in such a waveguide was measured by the technique of the Degree of Polarization of Photoluminescence. The measured stress map was modeled to quantify the spatial distribution of index change within the waveguide itself. The mode of the single-mode waveguide with the stress effects was calculated using the beam propagation technique. The resultant mode exhibited a double peaking which agreed well with the observed mode of the actual waveguide.

The second problem studied was that of crossed waveguides. Crossed waveguides are necessary in optoelectronic integrated circuits due to the multiple light paths and planar nature of the fabrication process. Each arm of these crosses requires good throughput with very little power coupled into the other waveguide. Although this is easy to achieve at large crossing angles, at angles below ≈ 10° a significant fraction of the light may couple into the crossing waveguide.

This thesis uses the beam propagation method to characterize the loss and crosstalk. Two modified versions of the X-crossed waveguide structure were developed and have shown crosstalk improvements, at angles below 10°, of greater than 20 dB. These improvements are easy to implement and are important due to the extra design freedom they allow the designers of optoelectronic circuits.

abstract: Doctor of Philosophy (PhD)


title: The role of telomere length and telomerase activity in cell immortalization and tumourigenesis

contributor:
Bacchetti, Silvia
Medical Sciences

subject:
Medical Sciences
Medical Sciences

abstract:
Human somatic cells have a finite lifespan. In contrast, since most cancers evolve through expansions of mutant clones with increasingly more transformed phenotypes, tomour cells may exhaust the proliferative potential of normal cells and possibly acquire an unlimited replicative capacity (immortality). Thus, one essential step in tumourigenesis may be the acquisition of an immortal phenotype. The results presented in this thesis suggest that telomeres, the terminal structures that prevent illegitimate recombination and ensure the proper segregation of chromosomes, and telomerase, the enzyme that elongates telomeres de novo, play critical roles in the process of immortalization of transformed cells both in tissue culture and in vivo.

In a tissue culture model of transformation we have shown that telomeres shorten as normal cells divided, as previously reported (Harley et al., 1990), and that, consistent with this observation, the cells lacked detectable levels of telomerase activity. Cells that were driven to divide beyond their normal lifespan by transformation with viral oncogenes did not directly acquire telomerase activity; consequently telemeres continued to shorten until a proliferative crisis, characterized by cell death, was reached. At crisis, chromosome ends contained very little telomeric DNA and appeared to be unstable since the frequency of dicentric chromosomes, aberrations that can be formed by the fusion of chromosome ends, increased. These data suggest that the critically short telomeres detected at crisis may no longer be functional, resulting in genomic instability and potentially cell death. Immortal clones which survived crisis maintained short, but stable telomeres and had telomerase activity. Similarly, malignant cells from the advanced stages of different cancers also had short telomeres and were telomerase positive. Moreover, in one cancer analyzed, the telomeres of malignant cells were found to be stably maintained in vitro and in vivo. These data, although correlative in nature, strongly suggest that, in culture as well as in vivo, telomerase must be activated to counter the lethal loss of telomeric DNA if cells are to become immortal.

abstract: Doctor of Philosophy (PhD)


title: β-adrenoceptors, adenosine 3',5'-cyclic monophosphate and polyploidy in vascular smooth muscle cells from different age-groups of spontaneously hypertensive and normotensive Wistar-Kyoto rats

contributor:
Lee, R.M.K.W.
Medical Sciences

subject:
Medical Sciences
Medical Sciences

abstract:
One of the possible contributing factors in the development of hypertension may be an accelerated or premature vascular ageing process, because of some similar structural and functional alterations in the vasculature, including an impaired β-adrenoceptor mediated vascular relaxation and an increase in polyploid smooth muscle cells. The primary objective of this study was to investigate the possible relationship between development of polyploidy and the plasma membrane β-adrenoceptor in cultured smooth muscle cells from the thoracic aortae of spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY) from 3-4-(prehypertensive), 10-12-(developing hypertensive), and 28-30-weeks (establish hypertensive) of age.

The major findings from this study are: (i) similar to the in vivo state, cultured smooth muscle cells from different age-groups of WKY and SHR contain a heterogeneous population of mononucleated and multinucleated cells, as well as diploid and polyploid smooth muscle cells; (ii) the expression of both smooth muscle cell polyploidy and β-adrenoceptor density increases with age in both SHR and WKY, however, this increase was significantly accelerated in SHR as compared to WKY, suggesting an accelerated or premature ageing process may be involved in SHR as compared to WKY; (iii) both SHR and WKY express functional smooth muscle cell β-adrenoceptors but many of the β-adrenoceptors expressed on cultured SHR smooth muscle cells are not coupled to adenylate cyclase; (iv) elevation of intracellular cAMP levels either by agonist activation of β-adrenoceptors or by direct activation of adenylate cyclase in cultured smooth muscle cells from 3-4-week old WKY and SHR and 10-12-week old WKY resulted in an increase in polyploid cells; (v) a β-adrenoceptor antagonist only partially inhibited the isoproterenol-stimulated increase in polyploid smooth muscle cells in both SHR and WKY; and, (vi) the development of polyploid SMC via the β-adrenoceptor-Gs-protein-adenylate cyclase-cAMP pathway is more efficient in cells from WKY compared to SHR.

From these findings, I conclude that: (i) the vascular β-adrenoceptor mediated signalling pathway plays a role in the development of polyploid smooth muscle cells; and, (ii) additional intracellular pathways, independent of the β-adrenoceptor-cAMP intracellular mediated signalling pathway, are involved in the development of smooth muscle cell polyploidy.

Since it is the resistance arteries (which show no significant increase of polyploid smooth muscle cells with age and/or duration of hypertension) and not the elastic large arteries (aorta) which play a significant role in the development of hypertension, these findings have more relevance to the premature ageing process than to the development of hypertension.

abstract: Doctor of Philosophy (PhD)


title: Conditioned Food Aversions: Illness-Induced Aversions to the Interaction of Gustatory and Nongustatory Cues

contributor:
Galef, B.G.
Psychology

subject: Psychology Psychology

abstract: Laboratory rats were habituated to drinking sucrose in one environment (the sucrose environment) and water in a second (the water environment). Subjects poisoned after drinking sucrose in the water environment subsequently exhibited a marked reduction in sucrose intake in the water environment. The same subjects did not exhibit depression of water consumption in the water environment and showed only a slight, nonsignificant reduction of sucrose intake in the sucrose environment. These results indicate that rates will form an aversion to a compound stimulus consisting of both gustatory and environmental components without forming an aversion to either the gustatory or environmental component in isolation.

abstract: Master of Arts (MA)


title: Lot Streaming Schedules in Flow Shops

contributor:
Steiner, George
Business Administration

subject: Business Administration, Management, and Operations

abstract:
Lot streaming is the process of splitting a job or lot to allow overlapping between successive operations in a multistage system. The use of transfer lots usually results in a shorter makespan and lower work-in-process inventory than without it.

In the thesis, we first study the discrete version of schedules which minimize the makespan for a single job in two- and three- machine flow shops. The optimal solution on s sublots can be obtained in O(s) time for the two-machine problem. We also present the first polynomial time solution for the three-machine problem. Two very good quality approximations for the discrete lot streaming solution in m-machine flow shops are also presented.

Other topics studied are the effect of setups (either detached or attached) on continuous lot streaming for three-machine flow shops. We show that, in most cases, the optimal schedule and its structure change substantially in comparison with the no setup case. In the presence of either detached or attached setups, the three-machine flow shop problem on s sublots can be solved in O(s) time.

abstract: Doctor of Philosophy (PhD)


title: Activation-dependent enhancements of synaptic strength in pyriform cortex efferents to the entorhinal cortex

contributor:
Racine, Ronald J.
Psychology

subject: Psychology Psychology

abstract: The entorhinal cortex is reciprocally connected with both neocortical sensory areas and the hippocampal formation, and is thought to play a pivotal role in learning and memory. Changes in synaptic strength are thought to provide the major neurophysiological basis for memory formation, but little is known about synaptic plasticity in the entorhinal cortex. The objectives of this research were to provide a basis for the interpretation of evoked potentials recorded from the entorhinal cortex following pyriform (primary olfactory) cortex stimulation in vivo, and to determine the conditions under which synaptic enhancements in this pathway may occur and contribute to lasting changes in the processing of olfactory information. The synaptic currents which generate field potentials in the entorhinal cortex following pyriform cortex and medial septal stimulation were first localized to the superficial layers of the entorhinal cortex using current source density analysis techniques in the anesthetized rat. This allowed changes in the strength of these synaptic inputs to be monitored in the awake rat by measuring evoked field potential amplitudes at a single cortical depth. Long-term synaptic potentiation (LTP) in this pathway was reliably induced following stimulation of the pyriform cortex with either epileptogenic stimuli, or with prolonged subconvulsive high-frequency trains. Further, stimulation which results in short-term frequency potentiation effects, was found to increase the amount of LTP induced. Concurrent stimulation of the medial septum at a frequency similar to that of the endogenous theta rhythm also resulted in a cooperative enhancement of the LTP produced. Computational modelling techniques were then used to formalize the heterosynaptic contribution of frequency potentiating medial septal inputs to Hebbian synaptic modification in entorhinal cortex. These results indicate that the frequency of rhythmic activity in sensory afferents and the activity of the medial septum may play critical roles in the regulation of synaptic plasticity in the entorhinal cortex.

abstract: Doctor of Philosophy (PhD)


title: Adenovirus Vectors for Cytokine Gene Expression

subject:
Medical Sciences
Medical Sciences

abstract:
Cytokines are polypeptide hormones that act nonenzymatically to regulate host cell functions. These glycoproteins make up a fourth class of soluble intercellular signalling molecules that also include neurotransmitters, endocrine hormones and autacoids and are believed to play a central role in tissue remodelling in inflammation, infection, and wound repair. Numerous studies have now implicated cytokines to be of critical importance in host defense, and a more complete understanding of their molecular function is essential. What is also evident is that the majority of biological functions assigned to cytokines have been characterized by in vitro systems.

In vivo confirmation of these reported biological functions is required and has been attempted. To date, this has been difficult to attain with the available animal models. While studies in transgenic mice have revealed a number of biological activities, they probably do not reflect normal physiological responses, since tissues chronically exposed to a cytokine throughout development may undergo alterations in its effector phenotype. Administration of recombinant protein is also problematic as repeated injections with large doses of purified recombinant protein are usually required to maintain physiologic concentrations due to the short half life of most cytokines in the circulation.

To overcome these problems, we have developed an alternative approach to investigate cytokine function in vivo. This approach, which we have defined as a "pseudo transgenic" animal model, uses recombinant adenovirus vectors containing cytokine genes to deliver and transiently overexpress cytokines in vivo in a tissue-directed manner to normal adult animals. Using this vector approach, cytokine expression can be targeted to a tissue in a way that may mimic more normal physiologic responses. In this study, recombinant adenovirus type 5 vectors capable of expressing the murine cytokines interleukin-5 (IL-5), interleukin-6 (IL·6), and RANTES were constructed to investigate the in vivo effects of these cytokines on immune and inflammatory responses.

The first vector constructed, Ad5E3mlL6, contained the murine IL-6 gene incorporated into the E3 region of the viral genome and was used to characterize the capacity of recombinant adenovirus vectors for cytokine expression. This vector was very efficient for cytokine expression both in vitro and in vivo. In addition, using an adenovirus vector containing luciferase as a reporter gene, we demonstrated that expression could be targeted in a highly tissue-specific manner dependent upon the route of administration.

Since IL-6 was reported to be the major mediator of the acute phase response and intraperitoneal administration of adenovirus vector primarily targeted cytokine expression to the liver and spleen in Balb/c mice, our initial investigation involved intraperitoneal injection of the Ad5E3mlL6 vector into Balb/c mice. This study confirmed in vivo biological roles for IL-6 as a major mediator of the acute phase response and as a B and T cell proliferation factor.

We then analyzed the effects of expression of IL-5 and IL-6, alone and in combination, on humoral immune responses in the mucosal tissue of the lung. Both cytokines, produced by T helper type 2 lymphocytes, are critical to the development and differentiation of B lymphocytes and in particular to IgA antibody production in the mucosa-associated lymphoid tissue (MALT) and bronchus-associated lymphoid tissue (BALT). These studies, using Ad5E3mlL5 (a vector expressing murine IL-5 in the E3 region of the virus) in conjunction with Ad5E3mIL6, provided in vivo support for the roles of IL-5 and IL-6 in inducing lung mucosal immune responses. Co-administration of these two vectors in C57BI/6 mice synergistically induced up to a-fold increases in antigen-specific IgA antibody production in the lung.

In addition, we studied the in vivo effects of RANTES, a molecule reported to be chemotactic for monocytes, on lung inflammatory responses. A vector, Ad5E3mRANTES, was constructed which contained the murine RANTES cDNA in the E3 region of the virus. This vector, when intratracheally instilled into Sprague Dawley rats, targeted expression to the mucosal tissue and induced the recruitment of monocytes to the lung within 24 hours. These effects were transient and this expression did not result in detectable lasting pathologic changes to the organ. These in vivo findings on RANTES function are consistent with its proposed function as a potent monocyte chemotactic factor.

Finally, we applied this newly developed adenoviral technology to immune modulation in an animal model of breast cancer. Mammary tumor cells from transgenic mice expressing the polyoma middle T antigen under the control of the mouse mammary tumor virus promoter were transplanted into syngeneic mice to establish subcutaneous tumors. These tumors were directly injected with control virus or Ad5E1mlL6A + vector, a replication-deficient vector containing the murine IL-6 gene in the E1 region of the Ad5 genome. We found that localized vector-derived expression of IL-6 could attenuate tumor growth.

In conclusion, the results of this thesis study demonstrate the practical use for recombinant adenovirus vectors to aid in the investigation of cytokine function in vivo. This demonstration that vector-derived expression of cytokine is high and can be targeted to specific tissues suggests their use as potential therapeutic agents for the modulation of immune responses in the treatment of cancer and other diseases.

abstract: Doctor of Philosophy (PhD)


title: Gender Perspectives on the Journey to Work in Toronto, 1901 to 1951

contributor:
Harris, Richard S.
Geography

subject: Geography Geography

abstract: There are large gaps in our knowledge of the journey to work in the first half of the twentieth century, particularly how patterns differed for men and women. My purpose is to examine the changing geographies of work and residence for a sample of men and women in Toronto. The central research problem is how the journey to work differed by gender. Two major hypotheses were developed to address the central research problem: that men travelled farther to work than women, and that the decentralization of work reduced the length of the journey to work in the study period. City directories are utilized to illustrate the changing geography of home and residence of a sample of over 50,000 Toronto workers between 1901 and 1951. Oral history evidence is also used to provide details on time and the commuting experience of Toronto workers. A discussion of the usefulness of city directories for historical commuting research and gender differences is also a component of the thesis. The conceptual framework for the thesis draws upon two major types of explanation. First, the journey to work was shaped by economic circumstances and, secondly, by cultural norms of the appropriate roles for men and women. The findings confirm the general patterns observed in the literature, that there were indeed significant gender differences. Men did travel farther to work than women in the early twentieth century. The research illustrates that work in Toronto between 1901 and 1951 generally remained more centralized than residence. Differences by occupation are evident, clerical workers, for example, travelling longer distances than skilled and semi-skilled workers.

abstract: Doctor of Philosophy (PhD)


title: Standing Outside the Gates: A Study of Women's Ordination in the Pali Vinaya

contributor:
MacQueen, Graeme
Religious Studies

subject: Religion Religion

abstract: The story of the origins of women's ordination into the Buddhist monastic order (sangha) is pivotal to the study of Theravāda Buddhist female renunciation---textual, historical, and contemporary. The story is not, however, easy to understand. It reflects an irreducible ambivalence toward women's renunciation. Though the story acknowledges women's capacity to attain nibbana (liberation from the bonds of rebirth), it also attributes to women's presence in the order a halving of the lifetime of the "true dhamma" (saddhamma, the Buddha's teachings which propel individuals to realization of nibbāna), and presents the Buddha as requiring the formal subordination of the women's order to the men's in an attempt to minimize the damage their presence will bring. This thesis provides an interpretation of the story in its relationship to the Pali Vinaya (the monastic code of rules and regulations). I argue that the story is a literary construct which functions to legitimize the vision of an ideal Buddhist renunciant that pervades the Pali Vinaya. Throughout the Vinaya, women (even ordained women) symbolize the outside world beyond the boundaries. They are that from which monks need protection and against which the Vinaya conception of identity is formed. This thesis makes four contributions to the field of Buddhist studies. It is the first full-length study of the story of women's ordination. It is also the first study of the Pali Vinaya to consider seriously the impact of gender on its categories, assumptions, and overall structure. As such, the thesis acts as a corrective to scholarship on Buddhism which assumes that the story is an accurate reflection or women's role in an early period of Buddhism's development. Additionally, the thesis could provide the basis for a more nuanced investigation of the social history of Indian Buddhism that accommodates the constructed nature of the texts.

abstract: Doctor of Philosophy (PhD)


title: Tools to Support a Formal Verification Method for Systems with Concurrency and Nondeterminism

contributor:
Parnas, David L.
Electrical Engineering

subject:
Electrical and Electronics
Electrical and Electronics

abstract:
With the availability of inexpensive computer hardware, software intensive systems are becoming sophisticated and pervasive, creating a need for software design methods that deliver robust and efficient systems. Unfortunately, most systems today are designed by trial and error, with designers having little insight into their correctness before they are implemented. The hallmark of an engineering method is the use of system models (prototypes) to verify designs by provably establishing essential characteristics of products before they are constructed. This thesis attempts to bring the craft of software construction closer to an engineering discipline, by transforming theoretical ideas in program verification and concurrency theory into a concrete method for the analysis of software requirements and system specifications. In our opinion, such methods will find wider acceptance if they are adequately supported by a set of tools. This thesis also describes tools that are being developed to support our verification method.

In this thesis, our primary concern is the problem of establishing that systems, when constructed in accordance with a design, will meet their required correctness properties. We describe a verification method, TOP, in which the description of a system (i.e., its design) is expressed as an abstract program in a programming language-like notation called MELA. We represent essential characteristics of the system (or its requirements) as predicates in a formal logic. The problem of establishing required correctness properties for the system is then reduced to the problem of establishing that a set of logical formulae hold. This is known as the verification problem. Our verification method, TOP, is mainly applicable to systems with complex control structures and simple data structures, and is tailored to systems that are designed not to terminate, and which often exhibit nondeterministic behaviour i.e., different runs of the system may produce different results, for the same inputs. Examples of such systems are operating systems, computer hardware, communications protocols, telecommunications systems, and control systems.

Our method offers a unified framework in which correctness properties may be verified using a combination of model checking (a fully automatic method), and theorem proving (a partially automated approach). This is desirable, because automated methods are applicable only to a limited class of systems. They are severely limited by the size of the state space generated by the abstract program denoting the system description - current limits are in the region of 108 states - roughly the number of states that could be generated by a program with a single 32-bit integer variable. Theorem proving approaches, while more general, are tedious and require specialised knowledge (the ability to provide proofs) on the part of verifiers. When carried out manually, proofs also tend to be error-prone. Theorem proving is particularly valuable in cases where the effort invested in carrying out a verification may be amortised over several projects (good examples are communications protocol specifications and distributed algorithms). Theorem proving can benefit tremendously from appropriate mechanical support, which can automate the tedious parts, in addition to playing the part of a relentless skeptic who demands the utmost precision and rigour in proofs. By presenting verifiers with a unified framework, therefore, we hope to extend the range of verification to systems that cannot be verified by either method alone.

One of the common complaints about theorem proving systems is that they are bewildering to beginners and hard to use. In this thesis we present an improved user interface for theorem provers. We also describe the details of system SNAP which has been built with this interface. SNAP has been designed for the purpose of checking proofs, in addition to providing partial automation of proofs. SNAP additionally allows users to carry out proofs at the desired level of abstraction. To support this, SNAP includes proof libraries and simplification algorithms based on conditional term rewriting.

Our method, TOP, has been used to verify problems derived from practice. We present two case studies that involved the use of TOP. In the first study, we provide a formal semantics for a tabular notation for requirements documents in terms of MELA. We then use model checking and theorem proving to establish certain "safety assertions" for the requirements specification of a system that mediates access to data shared by two processes. In the second study, we analyse liveness violations in a communications protocol standard, and verify that suggested changes to the standard have indeed fixed the problem. Finally, we conclude by describing ongoing work and suggestions for future research.

abstract: Doctor of Philosophy (PhD)


title: Construction and Characterization of Recombinant Human Adenovirus Type 5 Vectors

contributor:
Graham, Frank L.
Biology

subject: Biology Biology

abstract:
In recent years adenovirus (Ad) vectors have been used for the expression of foreign genes in mammalian cells, have been studied as vaccine vectors and more recently as gene transfer vectors for gene therapy. A number of properties make the Ad system a good candidate for each of these applications not the least of which is the extensive understanding of their structure and biology that has been gained through their use as a model system for studying all aspects of gene expression and DNA replication. The construction of recombinant Ad vectors involves the insertion of foreign DNA sequences into the Ad genome usually in place of compensating deletions made in early region 1 (E1) or E3. Deletions of up to 2.9 kb have been made in E1, which is not required for viral replication in complementing 293 cells, allowing the construction of conditional helper independent vectors with a capacity of 4.7-4.9 kb. A variety of deletions have been made in E3, a region which is nonessential for viral replication in any normally permissive cells. The most commonly used deletion of 1.9 kb allows the construction of nonconditional helper independent vectors with a capacity of 3.7-3.9 kb.

Even with our extensive knowledge of Ads a more detailed understanding of vectorology is required before recombinants can be confidently used in humans for vaccine and gene therapy purposes. For example it was generally assumed that adenovirus vectors are relatively stable and can package DNA up to 105% of the wt genome length. To more thoroughly address this issue the genetic stability of Ad5 vectors with E3 substitutions representing net insertions of up to 8.3% of the AdS genome was analyzed after serial passages in 293 cells. This investigation revealed that vector stability correlated with net genome size and vectors with the largest genomes rearrange extremely rapidly. This observation prompted the development of a new vector system (the BHG system) with larger deletions in E1 (3.2 kb) and E3 (2.7 or 3.2 kb) that can accommodate larger inserts. This system is the most versatile yet developed and allows the insertion of genes into E1 or E3 or both and mutations or deletions can be readily introduced elsewhere in the viral genome. The system provides a capacity of 8.3 kb.

Using the information gained in vector construction, and the new vectors systems that were developed, vectors were constructed that expressed various simian immunodeficiency virus (SIV) genes. There should be little doubt that the development of a safe, effective vaccine for human immunodeficiency virus (HIV) will provide the most secure and cost effective means of controlling HIV and AIDS. The infection of macaque monkeys with SIV provides one of the most relevant animal models for studying AIDS and for developing vaccines (Desrosiers and Ringler, 1989; Fultz, 1993). Information gained through the development and characterization of Ad/SIV vectors will have important implications in terms of developing a potential Ad/HIV vaccine.

abstract: Doctor of Philosophy (PhD)


title: Dynamic Mechanistic Model for Biological Nutrient (Nitrogen and Phosphorus) Removal Activated Sludge Systems

contributor:
Doid, P.L.
Civil Engineering

subject:
Civil Engineering
Civil Engineering

abstract:
The objective of this research was to develop and calibrate a dynamic mechanistic model for biological nutrient (nitrogen and phosphorus) removal activated sludge systems treating municipal wastewater. The IAWPRC (ASM1) model for non-polyP heterotrophic and autotrophic organisms (Henze et al., 1987a,b) and the Wentzel et al. (1989b) model for polyP organisms were merged to form a general activated sludge model. After a number of initial modifications the model was tested against literature data from laboratory-scale nitrification denitrification biological excess phosphorus removal (NDBEPR) systems. Based on the preliminary results, a number of specific areas were identified which required further study. These included (1) accounting for sludge production and oxygen utilization in BEPR systems; (2) denitrification behaviour in BEPR systems; and (3) other issues such as hydrolysis under unaerated conditions.

The main body of this thesis is presented as a series of five papers. The first paper (Chapter 4) presents a study of COD and nitrogen balances in activated sludge systems. The results suggest that systems incorporating anaerobic zones exhibit low COD balances compared to aerobic and anoxic-aerobic systems. Possible mechanisms for this "loss" of COD are discussed, including the possibility that the COD loss is related to fermentation processes occurring under anaerobic conditions.

The second paper (Chapter 5) presents a study of denitrification behaviour in BEPR activated sludge systems. Results of a review of microbiological studies and many continuous and batch reactor experimental studies indicate that a significant fraction of the polyP organisms can use nitrate as an electron acceptor in the absence of oxygen for oxidation of stored PHB and simultaneous uptake of phosphorus.

The development of a general activated sludge model for biological nutrient removal activated sludge systems is discussed in the third paper (Chapter 6). Several modifications were made to both the ASM1 and Wentzel et al. (1989b) model components, based on the results of literature review and model simulations. A fermentation process has been included for the conversion of readily biodegradable COD to short chain fatty acids (assuming a loss of COD). Hydrolysis of enmeshed slowly biodegradable COD under anaerobic conditions has been incorporated, as well as anoxic growth of polyP organisms. These modifications and others are discussed in this paper. The matrix representation and a description of the model processes are also presented, as well as a brief outline of influent wastewater characterization.

The application of the general model is demonstrated in the fourth paper (Chapter 7) for aerobic and anoxic-aerobic systems, as well as a number of nutrient removal (NDBEPR) systems for both steady state and dynamic conditions. Results of simulations show the model is capable of predicting sludge production and oxygen utilization for a range of system types and configurations, as well as tracking changes in a number of parameters including soluble phosphorus and nitrate concentrations.

In the final paper (Chapter 8) the consequences of the COD loss assumptions incorporated in the model are demonstrated for a number of experimental anoxic-aerobic and anaerobic-anoxic-aerobic systems. Results of model simulations indicate that without the assumption of COD loss, predictions of oxygen consumption and volatile suspended solids production are significantly over-estimated for NDBEPR systems (and to a lesser extent anoxic-aerobic systems). These systems apparently consume less oxygen and produce less volatile solids than aerobic systems for the same amount of COD removal.

In conclusion, the merits and weaknesses of the general model are discussed. An important feature of the model is that a single set of kinetic and stoichiometric parameters produced quite accurate predictions for the wide range of systems to which the model was applied (with the exception of the nitrifier growth rate - discussed in Chapter 6). This provides a degree of support for the model structure and integrity. Many aspects of NDBEPR modelling require further investigation, including: the COD loss phenomenon, the fermentation processes occurring under anaerobic (and possibly anoxic) conditions, the hydrolysis of slowly biodegradable colloidal and particulate organics (particularly under anoxic and anaerobic conditions), and the impact these aspects have on denitrification behaviour in NDBEPR systems.

abstract: Doctor of Philosophy (PhD)


title: Funeral Rites Participation and Health Services Utilization in Rural Ghana

contributor:
Matthews, David Ralph
Sociology

subject: Sociology Sociology

abstract:
Conventional health care services (CHCS) have failed to meet the health needs of many people in rural Ghana. Relevant literature highlights poverty, underdevelopment and inequities in allocation of resources as largely accountable. Currently in vogue and as a solution to these inequalities is the concept of comprehensive primary health care (CPHC) which implies community participation or "health by the people". Since its adoption and implementation, the CPHC strategy to health has not been successful in most of these rural communities, an issue that poses a new challenge to both "experts" and "students" of utilization studies.

In this study, funeral rites participation (as a sociocultural phenomenon) is used to examine the character and levels of use of CPHC services among the Dagaaba in the Upper West Region (UWR) of Ghana. Using a qualitative-ethnographic design to gather data, special emphasis is given to inter- and intra-gender variations in utilization patterns. The process of data analysis, like that of data collection, derives from grounded theory. This theory is especially suitable for determining health explanatory models of lay and professional people as well as for identifying which cultural beliefs and social norms influence healthcare practices.

Lack of viable economic activities in the UWR cause many able-bodied Dagaaba men to migrate. Over 50% of these migrants work in the minus where they fall victims to and die in epidemic proportions from new occupational accidents, injuries and diseases. The effects of such migrations and epidemic mortality of these men on the community's economic and social life are issues of great concern. Apart from the nutritional consequences of the socioeconomic deprivations, funeral rites, performed following death, have their impact on health. As part of a complex network of symbols and actions associated with life, health and illness, death rites redefine identities and inhibit the health seeking behaviour of participants of these rites. For instance, the symbolic structural and functional readjustments made, like "widow inheritance", in order to reach a new equilibrium and ensure continuity in the family inhibit the utilization behaviour of both the widow and the "heir". For them, the dead are actually not dead. Rather, they are transformed into a community of spirits (the "living-dead") policing and exerting influence on their behaviour in the human world.

Within the context of this belief system, the Dagaaba conceptualize and articulate the causes of most illnesses in terms of spiritual dysfunctions and/or relational fragmentations. Consequently, solutions to them are viewed in the context of spiritual renewal and relational reintegration. Healthcare is thus seen as a collective enterprise having little to do with the clinical reality of the individual and everything to do with the corporate interest of the community (the philosophy of N'taan be). In light of this, the study contends that to understand and facilitate utilization of CPHC services in the region (especially among the Dagaaba) we must depart from conventional models that explain services utilization in terms of macro-structure and micro-psychology. We must develop meso-models that identify with the meanings local people attach to ritual symbols and utilization actions.

abstract: Doctor of Philosophy (PhD)


title: The Nature of Chain-Plane Coupling in YBa₂Cu₃O₇

contributor:
Carbotte, J.P.
Physics

subject: Physics Physics

abstract:
The work in this thesis revolves around a simple model of the high temperature superconductor YBa₂Cu₃O₇_δ. Of all of the high temperature material YBa₂Cu₃O₇_δ is by far the most widely studied. Despite this, relatively little is understood about it. Although the structure of the unit cell has been known since the discovery of the material, its electronic structure is still a subject of intense controversy. Theories of the electronic structure range from the conventional theories of metallic systems with complicated band structure, to exotic theories of strongly correlated electron systems. Exotic theories are necessarily, difficult to work with, and we adopt the attitude that it is more fruitful to understand the strengths and weaknesses of the simplest models before pursuing more complicated approaches. For this reason, no attempt is made to provide a comprehensive theory of high temperature superconductivity. Instead a model is chosen which captures the few features of the structure of YBa₂Cu₃O₇_δ which we wish to study.

The main focus of the model is the link between two structural elements within the unit cell-the so called copper-oxide "planes" and "chains". Both the chains and planes are believed to play an active role in determining the highly unusual properties of YBa₂Cu₃O₇_δ. At the moment, relatively little is known about the chains, since the planes are suspected to be the more interesting of the two elements and have been more carefully studied. Recently, though, attention has begun to shift towards the chains.

In the chapters which follow, several physical properties of the model arc calculated. The calculations allow us to interpret a number of experiments, such as penetration depth, and YBa₂Cu₃O₇/Pb Josephson junction experiments. As a result of comparing the theory with experiment, we are able to make a few fairly broad statements about the electronic structure of YBa₂Cu₃O₇ in both the normal and superconducting states.

abstract: Doctor of Philosophy (PhD)


title: Analysis of Loss of Telomeric DNA During Replicative Aging of Human Cells and Examination of the Role of this Process in the Induction of Cell Senescence

contributor:
Harley, C.B.
Biochemistry

subject: Biochemistry Biochemistry

abstract:
Telomeres are nucleoprotein complexes located at the ends of all eukaryotic chromosomes, and are essential for genetic stability and viability. Telomere length decreases during replicative aging of normal human diploid fibroblasts (HDF) in vitro. These observations imply that telomere length provides a mitotic clock for the replicative age of normal somatic cells, and that telomere shortening may cause cell senescence. To further examine these predictions, telomere length was analyzed (i) on vitro, in young HDFs as well as senescent and near-senescent HDFs and (ii) in vivo, in HDFs and candidate hematopoietic stem cells. Mean terminal restriction fragment (TRF) length decreased significantly at a rate of ~ 15 bp/year in HDFs. Also, mean TRF length decreased with increasing donor age in CD34⁺CD38^(lo) hematopoietic cells obtained from fetal donors and adult donors of ages 19 and 59 years. These observations confirm that telomere length decreases not just during aging in vitro but also during aging in vivo. They also, imply that stem cells have a finite lifespan.

The observations that telomere length is proportional to replicative capacity in cultured HDFs from normal and progeroid donors and that telomere length is shorter in HDFs at the periphery of radial outgrowths relative to HDFs at the center suggest that telomere length is a valuable marker for replicative potential.

Interclonal variability in telomere length was significantly less at senescence than at early passage for HDF clones established from the same strain, in support of the existence of a critical telomere length in senescent cells. Calculation of mean telomere length at senescence for these clones and one other HDF strain yielded an upper estimate of 2-3 kb for the critical telomere length. However, the detection frequency of individual telomeres by fluorescent in situ hybridization (FISH) varied from telomere to telomere in both young and senescent cells. Furthermore, in pre-crisis SW26 fibroblasts, the long arm of one copy of chromosome 9, which has a relatively short telomere, is frequently engaged in an end-to-end dicentric chromosome. Also, a significant distribution of TRF lengths exists at all PDLs. These observations indicate that the shortest telomere length at senescence, which best represents the critical telomere length, is probably considerably less than 2-3 kb.

These observations support a causal role of telomere shortening in cell senescence. This has important implications for future treatment of cancer and therapeutic prevention of cell senescence during aging.

abstract: Doctor of Philosophy (PhD)


title: A Finite Element Contact Algorithm Applied to the Analysis of Expanded Tube Joints

contributor:
Dokainish, M.A.
Mechanical Engineering

abstract:
The study presented in this thesis aims at fulfilling an industrial need for solution methods suitable for the analysis of complex nonlinear engineering problems. A finite element contact algorithm is developed, implemented and verified. Furthermore, the algorithm is used for the numerical simulation of the hydraulic expansion of tube joints.

A variational formulation of the general contact problem is presented where the virtual work principle is adopted to arrive at the discretized equilibrium equations for two generic bodies coming into contact under the effect of the applied loads. The discretized contact constraint equations are derived geometrically from the kinematics of the potential contact surface nodes. A direct engineering approach is used to develop a solution algorithm which is applicable for the analysis of contact problems in general. No assumptions are made regarding the geometry of the contacting bodies, the location and extent of contact and the nature of the external loading. A non-classical bi-Iinear friction model is introduced where micro tangential relative displacements are allowed even under very light normal traction. The bi-linear law may be reduced to the classical Coulomb's friction law as a special case. The algorithm is made capable of handling nonlinear continuum finite elements, i.e. elements with curved sides. The equilibrium equations are solved iteratively to calculate the contact nodal forces which remove any overlap without augmenting the contact constraint equations into the original system of equilibrium equations. Instead, the contact constraint equations are solved as an inner loop in the global nonlinear iteration loop which follows the full/modified Newton-Raphson iterative technique. The developed algorithm is implemented in the in-house general purpose non-linear finite element program INDAP¹ and verified through the solution of illustrative examples covering a wide range of contact problems of static, elastic, elasto-plastic, conformal and non-conformal contact interactions.

The developed contact algorithm is used along with two finite element models to simulate the hydraulic expansion of tube joints. A 2-D plane stress model is used to investigate the effects of the different material mechanical properties on the joint strength. A 2-D axisymmetric model is adopted to overcome the limited scope of the plane stress model. The feasibility of ignoring the geometric nonlinearity and the friction interaction are investigated. A 2³ complete factorial numerical experiment is adopted to study the main and interaction effects of the expansion pressure, the initial radial clearance and the coefficient of friction on the residual contact pressure, representing the joint integrity, and the maximum residual tensile stress along the tube inner and outer surfaces, representing the joint quality. A new explanation to the break-off the joint strength when the joint is further expanded beyond a well-defined optimum is suggested. The adequacy of some strength measures is explored. The effects of the initial stresses and the cold-work surface layer along the tube outer surface are investigated.

abstract: Doctor of Philosophy (PhD)


title: A Study of Dividing Steam-Water Flow In T-Junctions: Experiments and Analyses

contributor:
Shoukri, M.
Mechanical Engineering

abstract:
Phase redistribution is a complicated physical phenomenon which occurs in dividing two-phase flow in T-junctions. In this study detailed experimental data of phase redistribution and associated pressure changes in T-junctions having horizontal inlet are presented for both annular and stratified inlet flows. Two phenomenological phase redistribution models for annular and stratified flows were developed. The objectives of the study are enriching the available data bank on the subject through the experimental measurements and enhancing current understanding of the phenomenon through model development and analysis.

Two-phase redistribution in T-junctions was found to be significantly affected by the inlet flow conditions, i.e. inlet flow pattern, inlet quality and inlet flow rates. The phase redistribution phenomenon also depends on the junction geometry, i.e. branch orientation and diameter. The experimental results showed that for annular flow in horizontal T-junctions an increase of inlet quality reduces the degree of phase redistribution while the inlet mass flux was found to be less significant. However, in stratified flow the increase of either the inlet superficial vapour or liquid velocities increases the degree of phase separation. The experimental results also showed that decreasing the branch diameter will increase the degree of phase separation. Moreover, downward orientation of the branch can reduce the branch flow quality significantly.

The pressure changes in T-junctions were correlated using simple momentum and energy balances for the run and branch respectively using measured void fractions. The run momentum correction factor was found to be independent of inlet flow conditions but was dependent on the junction geometry. The branch two-phase multiplier was found to depend on both the inlet flow conditions and junction geometry. Comparison of the present data on pressure changes in T-junctions with some available models showed that those models which account for phase redistribution effects were better than the others in correlating the present data, confirming the strong interdependence between the pressure changes and phase redistribution.

A general phenomenological phase redistribution model was derived based on the analysis of available models. This general model was extended to two phenomenological models for annular flow and stratified inlet flows. Each of the models included two submodels to account for two phase distribution in the inlet tube and phase redistribution in the junction. Comparisons of the present experimental data and some available models were made and the results indicate that most of the available models can predict 70% of annular flow data and 80%of stratified flow data within +40%of the measurements. The newly developed models in this study can predict 90% of the data within +40% for both annular and stratified flows.

abstract: Doctor of Philosophy (PhD)