title: Liquid-Liquid Extraction by the Slug Technique

contributor:
Baird, Malcolm H.I.
Chemical Engineering

subject:
Chemical Engineering
Chemical Engineering

abstract:
The slug technique proposed by Baird and Ho¹⁶ is a simple and easy way of obtaining the fundamental data on mass transfer coefficients in ternary liquid-liquid extraction. The technique yields a constant measurable interfacial area and the coefficients thus obtained from the experiments could be compared with those obtained by the penetration theory.

The technique, as proposed, operates on a cylindrical slug of the organic phase suspended freely by downflow of water. This is modified in this work, by means of a disc arrangement to accommodate changes in aqueous phase flow rate. It was observed that the disc, which holds the slug at the center of the tube, has also enhanced the mass transfer rates by improving the mixing inside the slug, the improvement being higher for smaller slug lengths.

The mass transfer coefficients in general were found to be lower than the penetration theory values. This could be due to any of the effects of dissolution of the solvent in the aqueous phase, hydrodynamic and surface conditions, variation of phase resistance with time, contaminants, and uncertainity about the distribution coefficient of the system: n-Heptane-Iodine-Water. Mass transfer rates in extraction with reactions were also found to be low and was thought to be due to violation of the assumption that the reaction between iodine and sodium thiosulphate is instantaneous. In the experiments with acetic acid as the solute, transfer rates were found to be higher than the expected because of Marangoni effects induced by the solute. It was concluded, however, that the technique will still be useful in obtaining the fundamental data with the use of a system with well-defined distribution data and redistilled solvents.

abstract: Master of Engineering (ME)


title: Cytomegalovirus Among Renal Transplant and Dialysis Patients

contributor:
Gent, M.
Medical Sciences

subject:
Medical Sciences
Medical Sciences

abstract: Cytomegalovirus (CMV), one of the herpes viruses, is a common infectious agent among immunosuppressed renal transplant patients. Although CMV infection is usually mild or asymptomatic among general population, it can result in critical illness, allograft rejection and even death among transplant patients. This thesis designs experiments for the study of CMV with respect to its incidence, morbidity and mortality as well as its effects on the cellular immunity among renal transplant and hemodialysis patients. The principles of incidence study are outlined, the concept of sensitivity, specificity and predictive value of a test explained, and the difference between the laboratory and epidemiologic usage of these terminologies are discussed. The sources of error in Lymphocyte Stimulation Test as an instrument to assess cell-mediated immunity are discussed. The complexity of morbidity study is also discussed. Sample size determinations for the incidence study, morbidity as well as cellular immunity studies are discussed. Statistical analysis of the data (when available) is discussed.

abstract: Master of Science (MS)


title: Software agents in electronic commerce: A decision support systems approach

contributor:
Archer, Norman P.
Management Science/Systems

subject: management science/systems

abstract: This dissertation presents a collection of research projects on software agents in electronic commerce (e-commerce). A common theme throughout this research is that agents are an innovation. We are interested in identifying conditions and design criteria that would lead to their adoption in e-commerce applications. We define and study a class of agent applications that fall under the Decision Support Systems (DSS) Approach, where users delegate part of a decision-making task to a software agent. We show how findings from traditional DSS research can guide the development of e-commerce applications that include software agents. Two frameworks are presented that organize research and development activity. The first framework looks at the kinds of knowledge that agents should possess if they are to assist in e-commerce decision-making and identifies some of the major research challenges in designing intelligent agent applications. The second framework is directed at development and design activities. It builds on models of buyer behaviour where perceived risk and frequency of purchase are two characteristics of purchasing situations that can help identify when buyers are expected to find agents useful. The results of two empirical studies suggested by these frameworks are presented. The first study was exploratory and identified consumer preferences for information display over searching and browsing tasks. This was a first step in a larger project aimed at designing adaptable agents to support consumers in different information-seeking modes. A second experiment studied consumer behaviour in the actual online purchase of a music compact disk. We found that subjects who used an agent made their purchase decisions in less time and made more-informed decisions than subjects who did not use an agent.

abstract: Doctor of Philosophy (PhD)


title: The Formation and Influence of the Slag Phase During the Reduction of Some Commercial Iron Ore Pellets

contributor:
Lu, W-K.
Metallurgy

subject: Metallurgy Metallurgy

abstract: An experimental investigation has been conducted to study the factors influencing the formation and behaviour of the primary slag phase formed in commercial iron ore pellets when reduced under conditions simulating those encountered in the iron blast furnace. Weight loss during reduction, metallographic and electron microprobe analysis techniques have been employed. Possible implications for blast furnace operation are discussed.

abstract: Master of Science (MS)


title: Marx's Theory of Commodity Fetishism

contributor:
Greensoan, Louis
Religion

subject: Religion Religion

abstract:
This thesis is an examination of Marx's use of the term fetishism in the context of an analysis of the theory of value and Marx's views on the relationship between social being and consciousness. It is argued that this contextualization is necessary in order to understand the genesis and development of Marx's use of the term. For this reason, the examination of Marx's theory of commodity fetishism in Capital is preceded by an outline of the theory of value in Chapter One and by an analysis of Marx's approach to the problem of the relationship beween being and consciousness in the years 1842-7 in Chapter Two.

It is a argued that the theory of fetishism is not a theory of ideology. It is a description of what is represented to occur when commodities are exchanged. It is a mystification which is internal to the structure of the commodity economy. It is not a psychological theory. Confusion on this point has led certain contemporary Marxists to assert that the theory of fetishism is an explanation of how people think in capitalist society. The thesis examies the sources of this confusion in Marx's writings.

abstract: Master of Arts (MA)


title: Hydrological and energy budget processes of the subarctic Canadian shield

contributor:
Woo, Ming-ko
Rouse, Wayne R.
Geography and Geology

subject: Geography Geology Geography

abstract: There has been only infrequent research of the hydrology and energy budget of the subarctic Canadian Shield even though it is the third largest ecozone in Canada. In order to investigate important and largely unknown processes, two study sites near Yellowknife, Northwest Territories were instrumented to measure the components of the energy and water budgets. This was done to determine the predominant water and energy flux processes acting on subarctic Canadian Shield hillslopes and to understand runoff generation processes in the region. Results indicate that the magnitude of the spring snowmelt and its potential to flood exposed bedrock portions of the landscape controls the energy budget in the early part of the summer. In wet years high latent heat fluxes early in the summer deplete moisture storage by the end of July, after which latent heat fluxes decrease until the end of the growing season. In drier years, sensible heat dominates the early summer energy budget to a much larger degree than observed elsewhere in the subarctic. It then becomes a very arid landscape. High evaporation to precipitation ratios throughout the summer are an important feature of the western Canadian Shield subarctic region and this is important to its hydrology. Soil offers high available storage relative to adjacent exposed bedrock because evapotranspiration exceeds precipitation and soil filled areas dry. These differences in available storage result in a spatially heterogeneous runoff response within the basin because landscape elements spill runoff only where available storage is filled. Lateral inflows can be the primary source for filling soil zones to their storage capacity. The dependence of downslope landscape units on lateral inflows from upslope results in a cascading pattern of surface runoff generation. This is significantly different enough from the variable source area concept to indicate that another process must be operating. The element threshold concept is presented to generalize the suite of hydrological processes acting on subarctic Canadian Shield headwater basins. The new concept has the following attributes. It more accurately defines the important processes contributing to variable headwater subarctic Canadian Shield landscape runoff. It accounts for the different hydrological processes that occur in headwater basins. It recognizes that saturation thresholds vary extensively across headwater basins and that this affects subsequent runoff generation, such creates a disjointed contributing area that expands downslope depending on slope, soils, and vegetation. This thesis shows that hydrological and soil-vegetation-atmosphere modeling must account for dynamic small scale landscape elements and hydrological linkages in order to accurately represent the runoff generation processes on the subarctic Canadian Shield.

abstract: Doctor of Philosophy (PhD)


title: Huang-po's Notion of Mind

contributor:
Shinohara, Koichi
Religion

subject: Religion Religion

abstract: The purpose of this study is to examine in detail the teaching of the ninth century Ch'an master, Hsi-yun of Mt. Huang-po, whose ideas were instrumental in determining the eventual course Ch'an Buddhism was fated to take. In this study, the teaching of Huang-po is considered within the context of the debate over the nature of "mind" current in Ch'an circles at this time. Within this context, Huangpo's understanding of "mind" is revealed, and the practice of "no-mind" is established. The thesis attempts to unravel the internal logic of Huang-po's thouqht, shedding some light on the central teachings attributed to him.

abstract: Master of Arts (MA)


title: Sankara as Theologian

contributor:
Arapura, J. G.
Religious Sciences

subject: Religion Religion

abstract: It will be my intention in this essay to demonstrate that Śankara-Vedānta should be addressed primarily as theology and not as philosophy. At the very least, such reference to Śankara-Vedānta as philosophy is misleading if left unqualified--and sometimes unjustified even when qualified. I am convinced that Śankara-Vedānta can be more accurately described as theology for mainly two reasons: Śankara's starting point is revelation (śruti) and his primary concern is of a soteriological nature, viz., the desire for liberation (mumuksutvam). These two essential characteristics of Śankara's thinking doubtlessly put some distance between his method and primary concern and those of modern, Western philosophy. I have specifically delimited the philosophical aspect of this distinction to the modern, Western era for reasons of clarity. Even by doing this, we can not come to an agreement on what is one, modern, Western philosophy, but rather only isolate some mainstream elements. However, I do think it feasible to maintain that--on the grounds of so important a set of distinctions as the respective starting points and primary concerns--we can point to differences between philosophy and theology and thereby clarify our understanding of Śankara-Vedānta.

abstract: Master of Arts (MA)


title: Damage in heterogeneous aluminum alloys

contributor:
Wilkinson, D.S.
Embury, J.D.
Materials Science and Engineering

subject:
Materials Science and Engineering
Materials Science and Engineering

abstract: The role of damage on the mechanical response of a heterogeneous material was investigated through both mechanical testing and x-ray tomography. X-ray tomography was used to obtain quantitative information on the evolution of damage through processes occurring at both the local and global scale. The results indicate that heterogeneity in the spatial distribution of particles does influence the damage process. However, the influence of having one particle or more interacting with another is limited to reducing the tensile deformation required to initiate damage. The rate at which damage evolves is similar for both isolated and non-isolated particles and increasing the number of neighbors around a non-isolated particle was determined to have no additional influence on the evolution of damage. These results, coupled with mechanical testing measurements of both global and local properties, were used to develop models describing the flow response of composite materials as damage accumulates. Models were developed to predict the effects of both particle multiple cracking and micro-crack linkage on the composite flow response. The models predict that both damage processes reduce the load bearing capability of the material over that of an undamaged composite, however the loss in load bearing capability is much more severe when micro-crack linkage occurs. Micro-crack linkage rapidly leads to a loss in global stability so that the strain at which the composite fails is significantly less than previous models suggest. The experimental behavior of the composite materials investigated in the modelling work favors that predicted by the micro-crack linkage model. Ductility predictions resulting from the micro-crack linkage model were sensitive to both the volume fraction and the matrix work hardening exponent. By varying the matrix work hardening exponent the micro-crack linkage model captured the experimentally observed range of ductility values present in literature.

abstract: Doctor of Philosophy (PhD)


title: The Construction and Evaluation of a Water Reclamation Kit Prototype for Isolated Application

contributor:
Benedek, Andrew
Engineering

subject: Engineering Engineering

abstract:
Unique sanitation problems exist in isolated communities, particularly those in Canada's North. These problems are compounded in the North by an undersupply of safe potable water and unsuitable ground conditions for most common Southern sanitation systems.

In an effort to meet some of these problems, a packaged water reclamation kit (WatRek) was designed. The kit was designed to be easily transported and assembled, and to produce an effluent suitable for recycle for non-potable use with a minimum of operator attention. Unit processes utilized in the prototype were: biological treatment, clarification, flow equalization, aerobic sludge digestion and activated carbon adsorption effluent quality of 30 mg/l COD and SS was considered adequate for recycle.

During evaluation the prototype met the effluent criteria at all times. The solids removal efficiency of the floating tube clarifier was found to be sensitive to energy dissipations in the aeration tank, of greater than 0.6 HP/1000 Igal. Overall net yield of microorganisms during the experimental period was estimated to be 0.08 g MLVSS/g COD removed. Seventeen days required to develop a biological floc in the aeration tank without an activated sludge seed.

The floating tube clarifier and hence the overall prototype operation were sensitive to hydraulic conditions. Prior to installation the prototype would require modification of the clarifier and the operational mode of the carbon column which was subject to inadequate backwashing. Improvements in the aeration tank system to maximize oxygen transfer and minimize agitation of the floating clarifier would also be required.

abstract: Master of Engineering (ME)


title: Influence of Elastic Mismatch and Nature of Interfacial Bonding on Toughness of Particulate Composites

contributor:
Nicholson, P. S.
Metallurgy and Materials Science

subject:
Materials Science and Engineering
Metallurgy
Materials Science and Engineering

abstract:
This work involves the study of crack-particle interaction in model brittle particulate composites where,

i) the interfacial bonding strength between second phase and matrix was continuously varied (glass - partly oxidized Ni system) and

ii) the presence and absence of elastic mismatch between second phase and matrix which gives rise to stress concentration around the particle was monitored. An ultrasonic fracture surface modulation technique was used which imprints the details of local crack-particle interaction on fracture surface.

The important results of this study are:

i) Both the interfacial strength and elastic mismatch important roles in improving the toughness of a particulate composite; optimum bond strength alone; without consideration of elastic mismatch may not improve toughness of a composite be a significant amount.

ii) For optimum toughening, second phase particles with a high intrinsic toughness which are well-bonded to the matrix and whose elastic moduli are equal to or less than that of matrix should be used.

iii) Due to the presence of elastic stress concentration, for second phase particles whose elastic moduli exceeds that of the matrix, a rather weak interfacial bonding is preferred to a strong interfacial bonding for effective crack particle interaction which will improve the toughness of a composite.

In summary, this work provides some guidelines for choice of proper second phase particles and matrix in the design of brittle particulate composites for optimum toughness.

abstract: Master of Engineering (ME)


title: Heat and Moisture Exchange in a Permafrost Active Layer, Churchill, Manitoba

contributor:
Rouse, Wayne R.
Geography

subject: Geography Geography

abstract: This thesis examines heat and moisture exchanges in the active layer of wet tundra soils during freeze-back and thaw. Measurements of rainfall, snow depth, air and soil temperature, soil moisture, and frost heave were recorded daily. Net radiation, soil heat exchange from soil solids and soil moisture, and soil latent heat exchange were calculated. It was determined that soil moisture is the most significant factor influencing soil heat exchange. A prolonged zero curtain effect of 4 to 6 weeks was related to high soil moisture levels. Soil heat exchange as a percentage of net radiation was 10% during snowmelt, decreasing to 3.5% by mid-summer. The latent heat released upon freezing or thawing of soil moisture can increase heat exchange as a percentage of net radiation to 258% during freeze-back. The calculated frost heave of 3 cm indicates that soil moisture was transferred to the freezing front to produce the measured 4.35 cm of heave. These results apply to wet tundra soils with a constant soil moisture.

abstract: Master of Science (MS)


title: Inner Biblical Exegesis: Hosea and the Jacob Tradition

contributor:
Cooper, A. M.
Religious Studies

subject: Religion Religion

abstract:
The purpose of the thesis is to study certain phenomena in the biblical texts as products of purposeful exegesis. Through the study of examples of inner biblical exegesis a better knowledge may be obtained of the compositional and transmissional techniques which resulted in the present shape of the biblical literature. It is suggested, therefore, that inner biblical exegesis offers empirical evidence which must be taken into consideration in any formulation of theories on the composition or transmission of the biblical materials.

The major emphasis of the thesis is that examples of inner biblical exegesis seem to indicate a greater freedom in the handling of authoritative traditions than has sometimes been suggested. While the latter emphasis is not new to biblical studies, it has not gained, complete acceptance.

In order to illustrate the functioning of inner biblical exegesis a detailed textual study of Hosea 12 was made. In the course of the latter study several new suggestions were made concerning the structure or the chapter and its meaning.

The thesis will hopefully contribute to a better knowledge of Hosea 12 and the Bible in general.

abstract: Master of Arts (MA)


title: Analysis of Cell Size Control in the Teast Saccharomyces Cerevisie: Isolation and Characterization of WHI3, A Dose-Dependant Inhibitor of Start

contributor:
Futcher, A.B.
Biochemistry

subject: Biochemistry Biochemistry

abstract:
Progression through the yeast cell cycle is controlled in the G1 phase at a point called Start. One prerequisite for the completion of start is growth to a critical cell size. Once critical cell size is obtained and other conditions have been satisfied, cells complete Start and become committed to a full cell cycle. One approach to identifying genes which regulate the cell cycle is to find mutants which confer a small cell size because they proceed through Start prematurely. For example, the CLN3-1 mutant has precisely these properties and encodes a stable hyperactive G1 cyclin variant that alters the timing of Start through premature activation of the Cdc28 protein kina 'e.

A tagged Ty-1 transposon mutagenesis procedure coupled with size enrichment was used to isolate a novel cell size mutant called whi3. The whi3 mutation is partially dominant and causes cells to commit to cell division at a reduced cell size. whi3 mutants are still capable of modulating cell size depending on the nutritional conditions. The size effects caused by the whi3 mutation are multiplicative with those of CLN3-1. In addition, the whi3 mutant is more a-factor resistant than the isogenic wild-type strain and has a slightly reduced mating efficiency. The whi3 Cln3-1 double mutant is nearly sterile and is largely defective for mating factor induced transcription.

The WHI3 gene was cloned and was able to complement the size defect of the mutant as well as increase the cell size of a wild-type strain. Extra copies of the gene carried on single copy vectors or integrated into the yeast genome increase cell size in a dose-dependent manner. Thus, WHI3 may encode a cellular metric used to measure cell size or mass. Sequence analysis indicates that this 71 kDa protein contains a domain common to a family of RNA binding proteins, the RNP motif. The deduced sequence of the protein is rich in serine residues and contains a small region rich in glutamine residues. Deletion of the WHI3 gene results in a small cell size phenotype, increased a-factor resistance and reduced mating efficiency, phenotypes shared with the Ty induced mutation. When WHI3 is placed under the control of the GALI promoter and induced, cells arrest in the G1 phase of the cell cycle. These results suggest that WHI3 encodes a dose-dependent inhibitor of Start by affecting the critical cell size requirement. It is hoped that these studies will increase our understanding of Start through the identification of molecules which regulate this transition.

abstract: Doctor of Philosophy (PhD)


title: On the Existence of Almost Uniform Linear Spaces

contributor:
Rosa, Alexander
Mathematics

subject: Mathematics Mathematics

abstract:
In this thesis we investigate the existence of a particular class f linear space called an almost uniform linear space. An almost uniform linear space is a linear space in which exactly two lines (called long lines) have sizes u and w, respectively, and all other lines (called short lines) have the same size k (k≥2). We determine the necessary conditions for the existence of an almost uniform linear space, in the cases where the long lines intersect (or are disjoint) and have the same size (or distinct sizes).

Next, we are interested in establishing the sufficiency of said conditions for almost uniform linear paces in which the short lines all have size two, three, four, or five. If we assume that the short lines all have size two, this follows immediately. Also, we can show that the conditions are sufficient for almost uniform linear spaces in which the short lines have size three and (i) the two long lines intersect and have the same size u, or (ii) the two long lines intersect (or are disjoint) and have sizes u Є {5,7,9} and w Є {7, 9, 13, 15}, where u ≠ w.

By generalizing the conditions in (ii), we provide partial answers to the existence question for almost uniform linear spaces in which one long line has size 6t + 5, 6t + 7 or 6t + 0 (t > 0) and the other long line has size w, w > 6t + r (r = 5,7,9). There are only partial solutions for the case of short lines of size four or five.

abstract: Doctor of Philosophy (PhD)


title: Prediction of Multicomponent Equilibrium Diagrams

contributor:
Kirkaldy, J.S.
Metallurgy

subject: Metallurgy Metallurgy

abstract: PubIished standard free energy changes and activity data for iron and its binary and ternary alloys have been used to evaluate the general linear series (Wagner) expansion of the activity coefficient and these were employed in turn for the accurate thermodynamic determinations of the liquids line and the field in steels with additions of Mn, Si, Ni, Cr, Mo, Cu, V, Nb and Co. Computer programs based on several derived analytic formulae were used to predict multicomponent constant composition and isothermal phase diagrams for total alloy additions up to 5 wt%.

abstract: Master of Engineering (ME)


title: Investigating the role of infections in human atherosclerotic heart disease

contributor:
Goldsmith, Charles H.
Health Research Methodology

subject:
Health Research Methodology
Medicine and Health Sciences
Medicine and Health Sciences

abstract: Human atherosclerosis is a disease of the blood vessel wall caused by an interplay between inflammatory, thrombotic, and lipid factors. A contributing or causal role for infection in that inflammatory response was first proposed in the 19th century, and with the advent of more sophisticated diagnostic techniques, a new search for a microbiologic etiology of human atherosclerosis has been rekindled. In this thesis, I examine methods for investigating whether infections contribute to human atherosclerotic cardiovascular disease. I explore three different technologies: serology (measuring antibody), inflammatory markers (as risk markers and as surrogates for infections), and the direct measurement of bacterial or viral DNA in the bloodstream. I examine three different study designs: cross-sectional, case-control, and cohort. Chlamydia pneumoniae , an obligate intracellular bacterium, is the primary focus of these studies. In addition, cytomegalovirus and other infections are included as controls, with the a priori expectation that these other infections would not be related to cardiovascular disease. We found a relationship between cardiovascular disease and C. pneumoniae antibody status in a small case-control study, but found no independent association in a large, prospective study. Inflammatory markers were measured in the prospective study, and were associated with cardiovascular events, yet no clear association between inflammation and infection was found. However, in developing methods for directly detecting bacterial and viral DNA in the bloodstream, we found that serology itself was not associated with current detection of bacterial DNA. Furthermore, we found a strong relationship between C. pneumoniae and smoking, and conclude that future studies need to examine the interaction between infection, inflammation, and smoking status.

abstract: Doctor of Philosophy (PhD)


title: Social Separation, Group Formation and Cohesion: A Study of West Indian Student Behaviour

contributor:
Shaffir, William B.
Sociology

subject: Sociology Sociology

abstract:
This thesis deals with the social phenomena of social separation, group formation and cohesion among West Indian students at McMaster University in Hamilton, Ontario. It explores and analyses the factors which come together to foster and produce a relatively cohesive group of students, operating in a "foreign" environment. These factors are, (1) West Indian perception of the way Canadians feel about them, (2) West Indian perception of Cultural differences between themselves and Canadians, (3) West Indian awareness and perception of their similarities in a foreign setting, and (4) The desire of West Indians to associate with others of like kind.

This process of social separation, group formation and cohesion occurs despite the heterogenous character of the societal backgrounds from which these students come.

abstract: Master of Arts (MA)


title: Time, cost and performance tradeoffs in project management

contributor:
Archer, Norman P.
Management Science/Information Systems

subject:
Management Information Systems
Management Information Systems

abstract: Successful project selection and management requires optimal supervision of corporate resources within specifications for time, cost, and performance. We developed a model and algorithm to support decisions on these three dimensions for project managers. It combines the advantages of the Program Evaluation and Review Technique (PERT) and the Critical Path Method (CPM). Our methodology leads to more accurate results than PERT/CPM, which typically results in optimistic planning due to less than actual completion time estimates that do not consider the possibility of more than one longest (critical) path. We also estimate performance measured by the Internal Rate of Return (IRR) of the project and the tradeoffs between time/cost and performance. We allow decision makers to calculate the probability that each activity will be critical, an indication of their relative importance for managerial purposes, in polynomial time. Furthermore, our methodology provides the means to obtain the optimal time/cost schedule of expected completion times as well as the variability in these time, cost, and performance estimates. We can apply our equations to rank the desirability of projects in a proposed portfolio, thus aiding in the portfolio selection process. A stochastic extension to the Analytic Hierarchy Process (AHP) is also used in conjunction with our methodology to demonstrate the application of uncertainty calculations in managerial group choice situations.

abstract: Doctor of Philosophy (PhD)


title: Modelling spectral and broadband UV-B (290--325 nm) irradiance for Canada

contributor:
Davies, J. A.
School of Geography and Geology

subject: Geography Geology Geography

abstract: This is a study concerning the modeling of UV-B irradiance at the earth's surface. It is timely because stratospheric ozone depletion has occurred globally as a result of increasing chlorofluorocarbons in the stratosphere. This reduction allows more UV-B irradiance (290-325 nm) to reach the earth's surface and cause detrimental biological effects. Presently there are few spectral UV-B radiation measurements. Therefore, irradiance models are useful tools for estimating UV-B irradiances in areas where measurements are not made. A numerical model to calculate spectral and broadband irradiances for all sky conditions is described and the results are validated with measurements for nine Canadian stations (Alert, Resolute Bay, Churchill, Edmonton, Regina, Winnipeg, Montreal, Halifax and Toronto). The model uses either the discrete ordinate radiative transfer (DISORT) or the delta-Eddington algorithms to solve the radiative transfer equation for a 49-layer, vertically inhomogeneous, plane-parallel atmosphere, with cloud inserted between the 2 and 3 km heights. Spectral calculations are made at 1 nm intervals. The model uses extraterrestrial spectral irradiance, spectral optical properties for each atmospheric layer for ozone, air molecules, and aerosol and surface albedo. Cloud optical depths τ c were calculated separately for overcast irradiance measurements for nine stations from 26 years of data. The delta-Eddington method performed well for producing τc and overcast broadband irradiances. A fixed τc value of 18.7 was found to be accurate for calculating cloudy sky irradiances at all stations except in the arctic. Twenty-six station years of irradiance measurements and model estimates are compared. Comparisons are made both for daily totals and for monthly averaged spectral and broadband irradiances. It is shown that the delta-Eddington method is not suitable for calculating spectral irradiances under clear skies, at short wavelengths (<305 nm), where absorption by ozone is high, and at large solar zenith angles. The errors are smaller for overcast conditions. The method was found to be adequate for daily total spectral (≥305 nm) and for broadband calculations for all sky conditions, although consistently overestimating the irradiances. There is a good agreement between broadband measurements and calculations for both daily totals and monthly averages with mean bias error (MBE) mainly less than 5% of the mean measured daily irradiance and root mean square error (RMSE) less than 26%, decreasing to below 15% for monthly averages. Agreement between mean monthly measured and calculated spectral irradiances is also good for wavelengths ≥305 nm. The accuracy of the Brewer instrument is questioned at wavelengths <305 nm at most stations. Comparison of the model broadband irradiances with simultaneous satellite-based results and Brewer measurements at six stations shows that the model performs as well as the satellite model but with the advantage that it can provide irradiance estimates throughout the day and, therefore, daily totals.

abstract: Doctor of Philosophy (PhD)


title: ΣN Strong Interactions

contributor:
Bhaduri, Rajat K.
Law, D. J.
Physics

subject: Physics Physics

abstract:
The availability Σ¯ atomic and ΣN scattering data are fitted consistently within a finite range potential model.

The most recent analysis of ΣN scattering data produced two possible sets of complex scattering lengths consistent with the observed cross-sections. These data, together with measured energy level shifts and widths in Σ¯atoms, are analyzed to determine if the combined data are consistent and also to extract effective Σ¯N potentials.

The calculations are performed by assuming Yukawa-shaped complex potentials for each Σ¯ spin, isospin channel. These potentials are then folded into the nuclear density distribution to produce the Σ¯ nucleus effective potential and the Schrödinger equation solved for the level widths and shifts. The potential depths and range are treated as parameters which are varied to minimize the total x² of the fit to the scattering lengths and atomic data. The possibilities of attractive or repulsive potentials are examined for those Σ¯N channels which produce positive scattering lengths.

Although the results of this analysis indicate that the atomic data can be fitted consistently with the scattering data, there is no conclusive distinction between the two sets of scattering lengths in this respect.

It is concluded however that the existence of a Σ¯n bound state is unlikely and that the Σ¯ spin triplet potential at least must be repulsive.

abstract: Master of Science (MS)


title: Cold work embrittlement of interstitial-free sheet steel

contributor:
Embury, J.D.
Perovic, D.D.
Materials Science and Engineering

abstract: The occurrence of brittle intergranular fracture during sheet metal forming operations or during in-service use in low carbon steels is often termed cold work embrittlement (CWE). Interstitial-free steels are especially susceptible to brittle intergranular fracture, as there is little free carbon in solid solution left to segregate to the grain boundaries, where its presence is thought to intrinsically strengthen the grain boundaries and indirectly strengthen the grain boundaries by impeding the segregation of deleterious elements such as phosphorus and tin. These embrittled grain boundaries, coupled with an increased flow stress from cold working, result in intergranular fracture, especially after deep drawing, with cracks propagating in the drawing direction. The purpose of the present work was to identify the key microstructural parameters controlling cold work embrittlement. Tensile tests performed on well-characterized undeformed and predeformed IF steel sheet indicated that the grain shape was a key microstructural parameter. A strain path dependent fracture criterion was developed and used to predict the occurrence of cold work embrittlement for forming operations from the evolution of the resulting intergranular fracture surface and the yield surface with deformation. A series of experiments on deep drawn cups were used to test the key predictions of the model. The role of grain shape, amount of deep drawing, segregation levels, macroscopic residual stresses, strain rate, and surface condition were further clarified. Although a fracture path investigation indicated that low angle boundaries were resistant to fracture, the density of these boundaries were insufficient to affect the bulk macroscopic fracture properties. The potency and amount of segregant at the grain boundary controls the cohesive strength of the grain boundary. Quantitative analytical electron microscopy detected higher levels of phosphorus segregation for batch annealed steel as opposed to continuously annealed steel. The higher level of segregation resulted in a greater susceptibility to CWE especially for severe deep drawing. The process of phosphorus segregation during recrystallization annealing was modeled by accounting for the migrating grain boundary.

abstract: Doctor of Philosophy (PhD)


title: Intellectual Intuition and Mystical Experience in the Realism of Jacques Maritain

contributor:
Vallée, G.
Religious Sciences

subject: Religion Religion

abstract: In this thesis we are examining intellectual intuition and mystical experience in the realism of Jacques Maritain. We discern two major degrees or levels of human knowing in his realism, one natural and the other supra-natural. Although essentially distinct, these two levels of human knowing are mutually compatible. Maritain seeks to establish a synthesis of the various modes of human knowing, and he attempts to accomplish this through the recognition of what distinguishes them from each other. In fact, Maritain argues that without the recognition of what distinguishes the various modes of human knowing from each other, serious error can occur. Intellectual, intuition here designates a mode of knowing which is associated with conceptualisation and strictly confined to the natural level of human knowing, and mystical experience (as distinguished from God's disclosure of Himself to man through communicable revelation) denotes a mode of knowing which is strictly supra-natural and incommunicable on the natural level of human knowing. In examining the distinction between intellectual intuition (primarily the intellectual intuition of being, which is for Maritain the human intellect's highest achievement on the natural level of human knowing) and mystical experience, as well as their mutual compatibility, we are attempting to comprehend Maritain's realism as a unified whole through what must necessarily be distinguished within it--intellectual intuition (especially the intellectual intuition of being) and mystical experience functioning as polar points in our discussion.

abstract: Master of Arts (MA)


title: Spontaneous Extravasation of Erythrocytes in Experimental Thrombocytopenia: A Study of the Erythrocyte Content of Thoracic Duct Lymph in Normal and in Thrombocytopenic Animals

contributor: Medical Sciences (Blood and Cardiovascular)

subject:
Medical Sciences
Medical Sciences

abstract:
A. A comprehensive and in depth review of the increased permeability of the vascular wall in thrombocytopenia was expedited. As part of this review, the following areas were covered: i. irradiation induced thrombocytopenia and the vascular wall defect; ii. anti-platelet serum induced thrombocytopenia and the vascular wall defect; iii. the endothelium and current theories on the role of platelets in supporting endothelial cell homeostasis; iv. the direct effect of irradiation and of anti-platelet sera on endothelium cell function and vitability; v. current models of explaining the endothelial cell changes and the escape of erythrocytes from the macroscopically intact capillaries and venules in thrombocytopenia; vi. a comparative analysis of the two thrombocytopenia models.

B. Although both qualitative and quantitative studies of the spontaneous extravasation of erythrocytes in irradiation induced thrombocytopenia have been made in the past, only qualitative electron microscopic studies have beeh reported up until now for the anti-platelet serum thrombocytopenic model. In the present work, we established such a quantitative estimate by studying the changes of the cellular content of the thoracic duct lymph in anti-platelet serum rendered thrombocytopenic animals. The level of those changes was lower than the level of corresponding changes reported by others in the irradiation thrombocytopenic model, and for equally severe thrombocytopenia. The possible reasons for this difference were evaluated and discussed.

C. The experimental technique developed here to study the vascular wall thrombocytopenic changes has certain advantages that renders it a useful tool in the study of platelet functions and in the evaluation of drugs claimed to have an anti-purpuric effect. One of the main attractions of this model is that it distinguishes between red blood cells extravasated through direct bleeding during the cannulation operations and spontaneously extravasated red blood cells post-operatively and post-APS. This is simply achieved by infusing the tagged RBC long after any possible bleeding has ceased and using those tagged RBC as a measure of RBC content in lymph. The animals are rendered thrombocytopenia post the infusion of the tagged RBCs. Furthermore, the model has been shown to be reversible and platelets can be transfused and survive into the thrombocytopenic animals shortly after the anti-platelet serum infuslon into the same animals.

abstract: Master of Science (MS)


title: Staples and the Development of the Capitalist Mode of Production: A Study of Mining in Canada 1845-1920

contributor:
Clement, Wallace
Sociology

subject: Sociology Sociology

abstract: A substantial amount of writing in Canadian Political Economy has emphasized the colonial/dependency relationship of Canada to Europe and the United States. The development of Canada has, in this schema, been viewed as a product of international systems of trade in raw materials and finished goods, such that the character of a given society, the type of social relations, its "state" of development, etc., are determined by the peculiar nature of the product(s) (staples) being traded. The theory shares, in essence, a number of similarities with those of mercantilism, by stressing the relationship between trade and wealth with respect to the development of society. In this thesis the question of staple production is approached in a somewhat different fashion; focussing on mining as a specific case of study. The development of mining in Canada is dealt with in relation to two basic concepts: (1) modes of production, including the process of transtion, and (2) the process of capital accumulation on a world scale. This development is viewed as being associated with the Canadian Industrial Revolution, with emphasis on the changing and developing relations between producers and non-producers interacting with the corresponding level of technological development. Under such circumstances the Industrial Revolution, as well as involving an increasing application of machinery, involved fundamental transformations of the relations between producers so that changes at the level of the organization of production occurred, both with respect to the possession of mines, and the actual organization of the labour force in mining. Further, in the discussion, the Industrial Revolution within Canada linked also to the developing international capitalist system. It is argued that the peculiar character of the development of mining in Canada was conditioned by the expansion of the capitalist mode of production, not only within national boundaries, but as a process of accumulation increasingly on an international level.

abstract: Master of Arts (MA)


title: Five essays on unionization and labour markets in Canada and the United States

contributor:
Kuhn, Peter
Burbidge, J.B.
Veall, Michael
Economics / Economic Policy

subject:
Labor Economics
Labor Economics

abstract: This thesis consists of five essays in the discipline of labour economics. The first essay uses cross-section time series analysis to estimate the impact of mandatory votes and card check on union certification success. The second examines the behaviour of Canadian union density from 1980 to 1998 and uses projections to look at the future of the Canadian union movement. The third investigates the decline of private sector U.S. union density from 1983 to 1999. The fourth essay considers the impact of three factors on the Canada-U.S. union density gap from 1980 to 1999: the difference in overall economic performance between the U.S. and Canada; structural change; and union recognition procedures. The fifth essay describes the behaviour of earnings per week, wages per hour and hours per week of prime-aged males by skill-group (identified by earnings quintile) in the U.S. and Canada from 1981 to 1997. This essay also provides evidence on relative downward wage rigidity in Canada.

abstract: Doctor of Philosophy (PhD)


title: Three studies in non-tantric Buddhist cult forms

contributor:
Yun-hua, Jan
Religious Sciences

subject: Religion Religion

abstract: This thesis attempts to present three to present three separate but related bodies of material which might contribute towards the eventual establishment of a new basic descriptive category in the field of Buddhist Studies: non-trantric pūjā. The first part deals with a previously unacknowledged form of the relic-cult; the second, with an equally unacknowledged cult of the book; the third with the image-cult. A fourth part indicates a few problematic factors involved in future research in the area.

abstract: Master of Arts (MA)


title: The effectiveness and efficiency of providing home care visits in nursing clinics versus the traditional home setting

contributor:
Browne, Gina B.
Nursing

subject: Nursing Nursing

abstract: Objectives . (1) Develop and implement a new model of home care delivery for home care services that would better serve post acute clients; (2) Evaluate this process by determining the effectiveness of the new model; (3) Suggest how the model would complement and be assimilated with the acute and community health care sectors; (4) Determine if the model is a more efficient way to use nursing resources; (5) Determine the satisfaction and acceptability of the clients and nursing staff with the new model. New service . Three nursing clinics were built, equipped and staffed to operate in three geographically different areas of a large Canadian city. The clinics served post acute, ambulatory Community Care Access Centre (CCAC) clients requiring wound dressings, intravenous therapy and other complex nursing care. Research design . Randomized control trial with initial data collection immediately post randomization and six weeks post discharge from hospital. Sample size . 99 Clients (45 experimental and 54 control), average age 50.8 years, eligible for CCAC services and retained for a 6 week period post CCAC discharge. Results . Study participants treated in a nursing clinic versus at home maintained their equivalent health status on eight health dimension and two summary mental and physical component scales of the SF-36. The average number of visits per clients in either venue was not significantly different. The average treatment time in the home was 46.4% longer (p < .001) than the clinic when travel and documentation time was included. This saving translates into a potential $10 million savings and the release of 146 full time equivalent RN resources, based on 6 million home care visits annually in Ontario. In addition, the satisfaction results reveal the home group was significantly less satisfied and inconvenienced waiting to be treated in the home. Implications . This study demonstrates that nursing clinics are an effective, acceptable and more efficient alternative for home visits for certain groups of clients.

abstract: Doctor of Philosophy (PhD)


title: Seeking to understand telephone support for dementia caregivers: A qualitative case study

contributor:
Ploeg, Jenny
Health Sciences

subject:
Medicine and Health Sciences
Medicine and Health Sciences

abstract: Telephone support is an intervention that is capable of delivering information, education, and psychosocial support to informal caregivers of persons with dementia. However, there has been very little research published examining the intervention of telephone support and its effect on the caregiving experience. A critical review of the literature revealed little information about the dimensions of telephone support and the experiences of those who receive and provide this intervention. Qualitative research is needed to achieve an enhanced understanding of telephone support services, and to understand the perspectives of those involved in this service. This thesis describes a qualitative case study seeking to understand the intervention of telephone support for caregivers of persons with dementia. In-depth interviews were conducted with eight dementia caregivers and four telephone support providers. The dimensions of telephone support identified were information, referral, emotional support, and convenience. The experiences of caregivers with this intervention revealed the sense of companionship offered through telephone support. The experiences of the providers revealed telephone support as a means to assist and empower caregivers to meet their needs for information, referral, and emotional support. The professionals also described some of the frustrations experienced when providing this form of support. After interpreting the data on the dimensions of the caregiving experience and the intervention of telephone support, it was evident how such an intervention can impact the dementia caregiving experience. Not only does telephone support conveniently meet the needs of caregivers, but it helps to minimize negative outcomes such as loneliness and role isolation, and helps foster positive outcomes such as mastery and self esteem. This new knowledge has implications for the planning and delivery of telephone support that will meet the individualized needs of caregivers of persons with dementia.

abstract: Doctor of Philosophy (PhD)


title: The Concept of Fit and Public Response to Community Mental Health Facilities

contributor:
Taylor, S.M.
Geography

subject: Geography Geography

abstract:
The focus of this thesis is on public response to community mental health facilities. The mentally ill are increasingly being moved out of the asylum and into small group homes and treatment facilities in the community. The response of community residents to this move, as far as it is understood, is generally one of opposition and rejection. Further understanding of response to community mental health facilities, with a view to predicting and improving that response, is vital to the success of the community mental health movement.

This thesis tests the link between the perception of fit and response to community mental health facilities for a sample of Toronto residents (n=1090). The perception of fit refers to the individual community resident's perception of how well the facility fits physically into the neighbourhood and how well the facility users fit socially into the neighbourhood. The perception of fit is measured as the perceived impacts of a facility on the neighbouhood, and as the similarity of perceptions of a facility and perceptions of the neighbourhood. In addition, community residents' views about fit are measured in an open-ended question.

Community residents are primarily concerned with the physical characteristics of the facility and its relative location in the neighbourhood. The perception of the fit between a community mental health facility and the neighbourhood varies with respondent awareness of facilities: those aware of a facility in their neighbourhood generally perceive a better fit than those not aware of a facility in their neighbourhood. Attitudinal response to facilities is significantly related to the perception of fit, and can be influenced by the physical characteristics of the facility, by community education, and by the operational characteristics of the facility which control the activities of the facility users.

abstract: Master of Arts (MA)


title: Wavelength division multiplexing cross connect networks

contributor:
Todd, Terence D.
Electrical and Computer Engineering

subject:
Electrical and Computer Engineering
Electrical and Computer Engineering

abstract:
Fiber optic communication is only 30 years old, but it has already become one of the technologies of choice for current and future high-speed communications. Unfortunately, the enormous bandwidth available in optical fiber cannot be accessed as a single communication channel. This is because each user station typically connects tot he network through its electronic interface whose speed is limited to the maximum electronic processing speed. However, access to this bandwidth is possible using parallel channel architectures, where each channel operates at rates which are accessible to electronic processing. Currently, wavelength-division-multiplexing (WDM) is being considered for this purpose. In local and metropolitan area networks, WDM may offer increased transmission concurrency compared with conventional single-channel designs, with only modest increases in station complexity. However, because of device limitations the number of available wavelength channels may initially be less than desired. As a result, spatial reuse of wavelength channels may be required to obtain designs which will support a reasonable number of stations. One option in this case is to perform media access across a spatial wavelength cross connect. In such a system, the total capacity may be n times that of a single passive star network, where n is the number of available wavelengths.

In this thesis, WDM cross connect networks are considered as a specific category of optical networks, which efficiently reuse the available wavelengths. The proposed networks are classified into two classes: single-hop and dual-hop.

In the single-hop case, time slot assignment techniques are considered which can dynamically schedule communications across the wavelength cross connect network. These new scheduling techniques are developed for a high performance dynamic medium access control based on the traffic demands of the network stations. Some simple random access methods are also introduced for the cases where some higher levels of simplicity are sought. Simulation programs are used to compare different scheduling methods. The results also show that the proposed methods perform quite efficiently.

The dual-hop class of WDM cross connect networks proposes a shared buffering scheme which simplifies network operation. These networks consist of two stages. In the first, the wavelength tunability of the user stations is used to route packets from a given local optical network (LON) to a destination LON. When packets arrive at a destination LON, they are buffered and transmitted onto the required destination wavelength. There are a number of advantages to this design including the elimination of protocols which would require both dynamic station transmitter and receiver tunability. This design also takes advantage of increasingly available commercial ATM (Asynchronous Transfer Mode) buffer/switch components. Several hybrid electro-optic options are considered. It is also shown that by using a novel optical multichannel buffering scheme, the number of required buffers can be significantly decreased.

abstract: Doctor of Philosophy (PhD)


title: Cold-formed steel compression members with perforations

contributor:
Sivakumaran, K.S.
Civil Engineering

subject:
Civil Engineering
Civil Engineering

abstract:
The research work of this thesis is concerned with the local buckling behaviour and the post-local buckling strength of perforated cold-formed steel (CFS) members subjected to axial compression loading.

Cold-formed steel sections are widely used nowadays as primary and secondary framing members in low-rise steel buildings. Although CFS members are essentially thin-walled framing elements, with a major susceptibility to local buckling, these members maintain a considerable reserve of post-local buckling strength prior to yielding. The post-local buckling strength of CFS members is largely affected by the sectional non-uniform material properties after the forming operation, the initial imperfections, the large deformation behaviour after buckling, and the possibility having utility perforations in the plate components of the members.

A finite element-based analytical model has been developed in this thesis to investigate the post-local buckling behaviour and the ultimate strength of non-performated and perforated CFS compression members. A large deformation degenerated shell finite element was used to model the surface of CFS sections. The kinematic formulation of the degenerated shell element was enhanced using the method of "assumed strain fields", to eliminate any locking program problem of the element. Special consideration was given in the finite element model to the geometric imperfections and the loading technique of CFS compression members.

Tensile coupon tests and residual stress tests were performed on CFS channel sections, in order to determine the effects of the cold forming operation on the distribution of the material properties across CFS sections. based on the results of these tests, analytical models for the stress-strain relationship, the yield strength distribution, and the residual stress distribution across CFS sections were developed and incorporated in the finite element model of CFS compression members.

A seris of CFS channel stub-column tests was performed to verify the deformation and ultimate strength predictions of the proposed finite element model. The tests were also used to investigate the effects of perforations on the behaviour and load capacity of CFS members in compression. The finite element model was then used to assess the axial stress distribution and the effective design width of perforated plates of CFS compression members. This assessment was performed through a parametric study on the perforation and the plate parameters.

Two effective design width equations for stiffened compression plates with square and elongated perforations were developed, based on the analysis of the finite element results. The ultimate load predictions of the two equations were compared to the stub-column test results of this thesis, and several other test results from the literature. The proposed equations proved to give accurate and safe predictions for the effective design width and the ultimate strength of perforated CFS compression members.

abstract: Doctor of Philosophy (PhD)


title: Dynamics and control of a two link flexible planar manipulator

contributor:
Elbestawi, M.A.
Mechanical Engineering

subject:
Mechanical Engineering
Mechanical Engineering

abstract:
A lightweight manipulator has many desirable features. The structural flexibility associated with lightweight manipulators often results in mechanical vibrations and consequently leads to long settling times and position inaccuracy. The aim of the current study is to investigate the dynamics of a two degree of freedom manipulator with elastic joints and very flexible arms and develop a proper control strategy. The dynamic model of manipulator is derived with the Lagrangian formulation and the assumed-modes approach. The eigenvalues and eigen-functions of the flexible arms are determined by the transfer matrix method. The dynamic effects of friction at the joints, gear blacklash within the actuation, and internal structural damping of the arms are all considered. The derived theoretical model is verified by experiments.

The parametric analysis is to designed to examine the effects of the major system parameters on the dynamic performance of the manipulator. The dynamic interactions between the members of the manipulator are also investigated.

The power balancing technique is extended for distributed parameter systems and a new approach for model order reduction of nonlinear systems is proposed. Using the derived power elements of the original system states as a criterion, the model reduction is performed in the original physical coordinates. The proposed technique is applied to the manipulator. It is found that the bending vibrations of the flexible link are dominated by its first two natural modes. The contributions of the higher modes are negligible.

A model reference adaptive control algorithm originally developed by Sobel is modified and used for the control of manipulator with an unknown payload. It is shown that the modification improves the algorithm's performance significantly. Computer simulations are performed to examine the algorithm's properties and select proper values for the gain matrices. Real-time testing is implemented to validate the theoretical analysis. It is found that the proposed algorithm provides satisfactory performance of the closed-loop system.

abstract: Doctor of Philosophy (PhD)


title: On trellis coded continuous phase frequency shift keying

contributor:
Taylor, D. P.
Electrical and Computer Engineering

abstract:
This thesis reports my research work in the area of trellis coded continuous phase frequency shift keying (CPFSK). Previous approaches [1, 2, 3, 4, 5] applied binary convolutional codes to CPFSK to achieve power and bandwidth efficiency. However, the work in [6] and part of this thesis show that no single approach among previous approaches can be outperformed by the others if only binary convolutional codes are considered.

A new coding scheme based on cnovolutional codes on the ring of integers modulo-P is shown to be a natural way to apply trellis coding to CPFSK [7]. Recent work has decomposed CPFSK into two parts; a linear encoder with memory, called the continuous phase encoder (CPE), and a memoryless modulator (MM), where the CPE often has a code structure defined over the ring of integers modulo-P. The combination of modulo-P convolutional channel encoder (CE) and the CPE, is a linear modulo-P encoder. Design examples are given for rate 1/2 coded quaternary CPFSK with modulation indices 1/2 and 1/4, and rate-2/3 coded octal CPFSK with modulation index 1/8. Combinations are optimized in the normalized minimum Euclidean distance sense for a given total number of states in the overall maximum likelihood sequence estimation (MLSE) receiver. Numerical results show that this new coding scheme consistently achieves better performance than previous schemes. [1, 2, 3, 4, 5].

An upper bound on the bit error probability (BER) for ring convolutionally encoded CPFSK is derived. The bound shows that feedback-free CPFSK usually has a smaller error coefficient than CPFSK. The minimum Eucildean distance is a good parameter for estimating performance, and the ring convolutionally encoded CPFSK has a good BER for both moderate and practical signal to noise ratio.

abstract: Doctor of Philosophy (PhD)


title: Narrative Structure in II Kings 5

contributor:
Combs, A.E.
Religious Studies

subject: Religion Religion

abstract:
The thesis is primarily a consideration of the narrative contained in II Kings 5. The problem which the thesis addresses is the understanding and interpretation of that narrative in light of a theory of literary analysis. What was desired was an analysis of the internal structure of the narrative and a means for relating that structure to the meaning of the narrative.

The first chapter presents the major concepts of Tzvetan Todorov's theory of Iiterary structure and provides some background to his method of analysis. Here we show that there are some basic structures, in the description of narrative and that these can be found in any piece of narrative. There is also a sample application of Todorov's method to the narrative of Genesis 22.

The second chapter presents a translation of II Kings 5 with notes on the text. Here we present the translation which forms the basis of the analysis in the third chapter.

The third chapter represents the body of the thesis, encompassing the actual analysis of II Kings 5. The analysis reveals that there are reciprocal structures of affliction/cure and submission/insubordination which provide the basis for the presentation of the character of the prophet Elisha. We conclude that the issue of leprosy and its cure serves only to focus the reader's attention upon the figure of Elisha, who forms the centre of the narrative and about which the narrative speaks.

The thesis argues that the application of literary methods to the biblical text can prove useful in understanding the meaning of the Bible.

abstract: Master of Arts (MA)


title: The Influence of on Biological Sex on Cognition and Hemisphere Specialization: A Study of Turner Syndrome

contributor: Medical Sciences (Growth and Development)

subject:
Medical Sciences
Medical Sciences

abstract:
The primary focus of this research was to investigate the possible influence of biological sex, specifically the sex chromosomes and hormones, on level of cognitive abilities and pattern of hemisphere specialization in humans. Normal males, and females are known to differ in level of cognitive abilities, with males typically having a higher level of spatial ability than females, and females achieving higher scores on tests of several aspects of linguistic ability. A growing body of research indicates that the sexes may also differ in degree of hemisphere specialization, with males being more lateralized than females. It has been suggested that degree of hemisphere specialization for spatial and linguistic processing may be related to the level of these cognitive abilities. The specific hypothesis of this research was that since the sexes differ in cognitive abilities and perhaps in hemisphere specialization, then perhaps the sex chromosomes and hormones may play a role in determining patterns of neural organization and cognitive abilities.

This hypothesis was explored by comparing a group of eight Turner syndrome subjects to normal control groups of both females and males. Turner syndrome individuals were studied because they do not have a normal second X chromosome as do normal females or the Y chromosome of normal males. Thus they are genetically different from both normal males and females. Nor do Turner syndrome individuals have normal sex hormone production. Thus the possible role of these biological variables could be studied. However, on the basis of this syndrome alone, the relative importance of these factors cannot be disentangled. The study of Turner syndrome also allows one to rule out environmental factors since Turner syndrome individuals phenotypically resemble normal females. Previous research has indicated that TS individuals have a deficit in spatial ability compared to normal females.

Male and female control subjects were matched with the Turner syndrome subjects on aspects of both Verbal and Performance IQ. Each group had a mean age of approximately 17 years.

A battery of tests measuring spatial ability, linguistic ability and hemisphere specialization was administered to the eight subjects in each of the three groups. A trend toward bilateral representation for linguistic processing was observed in the Turner syndrome group. Right hemisphere specialization for the processing of nonverbal stimuli appeared to be normal.

With regard to cognitive abilities, the Turner syndrome subjects were found to perform at a normal level on many tests such as a phonetic reading test, tests of verbal intelligence, and tests of some aspects of spatial ability, compared to normal males and females. However, their performance was found to be deficient on some aspects of a test of three-dimensional perception, a word recognition reading test, a written word fluency test and a coding or digit symbol test. It is suggested that a common element required in the performance of these tests on which Turner syndrome individuals were deficient may be some aspects of visuospatial perception and memory which become particularly deficient when there are time constraints.

Given the cognitive differences and the tendency toward a difference in hemisphere specialization between the Turner syndrome and normal subjects, it is suggested that either the lack of a second X chromosome or the lack of normal sex hormones, or both, play a role in determining the level of cognitive abilities and pattern of hemisphere specialization in normal humans. The evidence from this and previous studies suggests that the absence of a normal second X chromosome alone may underlie the differences between Turner syndrome subjects and normal females.

Some of the methodological problems encountered in this type of research are also discussed.

abstract: Master of Science (MS)


title: A Research Design to Evaluate Ultrasound in Patients with Shoulder Stiffness

contributor:
Tugwell, Peter
Health Care Research Methods

subject:
Health Services Research
Health Services Research

abstract: The objective of this thesis is to propose a methodology of the evaluation of the effectiveness of therapeutic ultrasound and exercise in physiotherapy outpatients with shoulder stiffness. The comparison group is to obtain exercise alone. The results of the study are to be analysed using an analysis of covariance with suspected confounding variables as the covariates.

abstract: Master of Science (MS)


title: Methylation and Chromatin Conformation of Adenovirus Type 12 DNA Sequences in Transformed Cells

contributor:
Mak, S.
Biochemistry

subject: Biochemistry Biochemistry

abstract: The DNA blot hybridization technique was used to study the integrated adenovirus type 12 (Ad 12) DNA sequences in three cell lines established by transformation of baby rat kidney cells with the leftmost 16.5% of the Ad 12 genome. The cell lines 702-C1, 702-C2, and 702-C3 contained respectively 3 - 4, 9, and 4 copies of the DNA used for transformation, integrated at 1, 9, and 4 distinct sites in cellular DNA. Partial copies of the transforming fragment were detected at additional integration sites. Methylation of CCGG sequences at the viral integration sites was investigated, using the methylation-sensitive restriction endonuclease Hpa Il and its methylation-insensitive isoschizomer Msp I. In lines 702-C2 and 702-C3 some integrated copies of the viral DNA were methylated at all CCGG sequences while other copies were methylated at only some of these sequences. In line 702-C1 no viral CCGG sequences were methylated. Limited DNase I digestions of transformed cell nuclei were used to examine the chromatin conformation of the methylated and unmethylated viral DNA. A correlation was found between the absence of methylation at viral CCGG sequences in lines 702-C2 and 702-C3 and preferential cleavages by DNase I of the chromatin around these sequences. Results reported here suggest that these preferential DNase I cleavages occur at sites which are hypersensitive to DNase I. If so, the cleavages may be unrelated to the DNase I-sensitive nucleosome structure which has been associated with transcriptionally active genes.

abstract: Master of Science (MS)


title: Studies on the Activation of Nitrofurans

contributor:
McCalla, D.R.
Biochemistry

subject: Biochemistry Biochemistry

abstract:
Nitrofurans, initially developed in the 1940's as antibacterial agents, have recently been shown to have mutagenic and carcinogenic effects. Nitrofurans exert such effects after metabolism by bacterial and mammalian nitroreductases to produce short-lived, electrophilic intermediates which react with nucleophilic centres of protein and DNA. To characterise the putative intermediates of nitrofurazone, an in vitro activation system was used in which synthetic L-lysine peptides were used to trap the reactive species. Present studies indicate that a small amount of binding of 'activated' nitrofurazone to lysine does occur but the amount of adducts formed is insufficient to permit structural analysis.

The bacterial nitroreductases are of two types: type I nitroreductase is active under aerobic conditions while type II is active only under hypoxic conditions. Analysis of crude extracts of type I reductase of wildtype and mutant strains of E. coli K12 by chromatography on DEAE-cellulose has resulted in the separation of three distinct activities which catalyse the reduction of nitrofurans probably by different enzymatic pathways. Two of the activities were previously identified but the third is apparently inactivated by MnCl₂ which has been used as a partial purification step in the past.

The mutagenic potencies of nitrofurans vary over a wide range: for the four nitrofurans, AF₂, ANFT, furazolidone and nitrofurazone, there is an 500-fold difference between the strongest and weakest mutagen. The overall rate of reduction and the kinetic constants of the type I nitroreductases with the four nitrofurans as substrates do not vary by more than a factor of three and thus cannot account for the observed differences in mutagenicity, however, the stronger mutagens do produce a larger yield of macromolecule-nitrofuran adducts than the weaker mutagens. Therefore, mutagenicity appears to be related to the stability and electrophilicity of the 'activated' nitrofurans.

abstract: Master of Science (MS)


title: Identification and Characterization of a Transient Embryonic Antigen in the Chick

subject:
Medical Sciences
Medical Sciences

abstract:
Transient embryonic antigens have been described in many systems in development. Although their function has not yet been elucidated their detection in the embryo but not in the adult state suggests a direct relationship with embryogenesis. The present investigation was undertaken in order to characterize and study a transient antigen (TEA) in chick embryo brain extracts.

TEA was identified by using specific antiserum prepared against 9 day embryonic chick brain extract. The antiserum was first absorbed with adult serum, liver and kidney extracts to remove non-neural antibodies. Then adult brain extract was added to remove antibodies directed against adult neural antigens. This antiserum (TAS) was then considered to be both embryo and neural specific. However, subsequent studies demonstrated TEA in extracts of 9 day embryonic liver, kidney and serum in concentrations similar to that found in 9 day brain extracts. TEA was therefore not specific to neural tissue as initially considered.

TEA demonstrated anodal migration in an electric field, similar to an alpha-globulin at pH 8.6. Ontogenic studies using immunoelectrophoresis and the quantitative technique of rocket immunoelectrophoresis were performed. TEA was present by 2 days incubation, and an initial peak at 4 days was noted. From day 6 on, TEA accumulated until a maximum concentration was reached at 12 days incubation. TEA levels then decreased until it could no longer be detected in 20 day embryo or adult brain extracts.

Molecular exclusion chromatography revealed the molecular weight of TEA to be 73,000 daltons. Isoelectric focusing demonstrated the isoelectric point at pH 4.8. The antigenic site of the TEA molecule was considered to be proteinaceous on the basis of its sensitivity to pronase; however it was not hydrolysed by either trypsin of chymotrypsin.

Based on the ontogenic pattern and the physical and chemical characteristics it was concluded that TEA was a chick alpha-fetoprotein. The possible role of TEA in embryonic development and the mechanisms of its regulation were also discussed.

abstract: Master of Science (MS)


title: A General Approach to Common-Mode Signal Rejection with Application to Myo-electric Signal Measurements

contributor:
Barber, H.D.
Chisholm, S.H.
Electrical Engineering

subject:
Electrical and Electronics
Electrical and Electronics

abstract:
A typical instrumentation problem is the detection of a differential signal in the presence of a common-mode signal. In the case of measuring myo-electric signals, the common-mode signals present can be 10²-10⁴ larger than the differential signal. In such instances, the attenuation of these unwanted common-mode signals require complex circuit designs.

In this work an investigation of the common-mode signal path led to the development of a general approach to the problem of unwanted signals arising from common-mode signal sources. It was found possible to write the overall common-mode gain as a product of the differential amplifier common-mode response and the isolation gain. The isolation gain depends on the ratio of the impedance of the common-mode signal path to the differential amplifier input impedance. The impedance of the common-mode signal path may be increased by employing in the amplifier system a self-contained power supply and an output coupler device such as a transformer.

The general approach was used to design an amplifier system to measure myo-electric signals. This amplifier system gave a much improved common-mode signal rejection over currently used systems which typically have 40 db of differential gain but only -30 db of common-mode gain at 60 Hz. The improvement in common-mode signal rejection was 25 db.

abstract: Master of Engineering (ME)


title: Production and Characterization of Monoclonal Antibodies Against Herpes Simplex Virus

contributor:
Bacchetti, Silvia
Medical Sciences

subject:
Medical Sciences
Medical Sciences

abstract: Methods for the production of hybrid cell lines (hybridomas) secreting monoclonal antibodies against specific antigenic determinants have recently been developed (Kohler G. and Milstein C., Nature 256, 495, 1975). Monospecific antibodies to Herpes simplex virus (HSV) antigens would greatly facilitate the analysis of HSV type-specific determinants, be of use in molecular studies of virus-cell interactions and could have potential applications in immunization against HSV infections. To this end, spleen cells from HSV2-immunized BALB/c mice have been fused to a BALB/c derived HGPRT myeloma line (Sp 2/0 Ag-14) and the resulting hybrids selected in HAT medium. From 13 successful fusions, 102 hybrid populations secreting antibodies recognizing antigenic determinants specified on HSV2-infected cells have been identified by FITC-immunofluorescence, an ELISA method or a ¹²⁵I-protein A binding assay. Ten of the positive hybrids have been cloned by limited dilutions to generate 124 monoclonal lines reacting specifically with HSV-infected but not with mock-infected cells. High titres of anti-HSV specific antibodies have also been detected in two ascitic fluids recovered from tumors induced in mice by injection of positive hybridomas. Preliminary data on the characterization of two hybridomas in terms of the subclass of immunoglobulins they secrete and the specificities of antibody they define has also been obtained.

abstract: Master of Science (MS)


title: Isolated Intrapulmonary Arterial Responses To Vasoactive Amines and Prostaglandins

contributor:
Forrest, J. B.
Medical Sciences

subject:
Medical Sciences
Medical Sciences

abstract: The response of the intrapulmonary artery (IPA) to a variety of endogenous lung amines and prostaglandins (PG) was examined to determine if a differential sensitivity to these vasoactive substances existed between segments taken from two sites on the artery. Longitudinal strips of proximal (PIPA) and distal (DIPA) segments of the left lower lobar intrapulmonary artery were taken from rabbit lungs and isometric tension measured during superfusion abt 37°C with physiological saline. Full or partial dose-response curves were obtained for 5-Hydroxytryptamine (5HT), Histamine (HIS), Norepinephrine (NE), Isoproterenol (IsoP), Arachidonic Acid (AA), PGA₁, PGB₁, PGB₂, PGE₁, PGE₂ and PGF₂α. In addition to pharmacological studies, length-tension properties of the segments utilized were examined and a qualitative analysis of smooth muscle content and orientation was undertaken. All prostaglandins elicited contractile effects, of varying magnitudes, at high doses. Prostaglandins A₁, E₁, and E₂ produced little or no contractile responses or slight relaxant activity in unstimulated PIPA and DIPA segments at low doses. 5HT contracted both PIPA and DIPA segments in a dose dependent manner, however, proximal segment maximal effects and sensitivity were significantly greater than those of the distal segment. Both PIPA and DIPA segments contracted to HIS and maximal effects were similar both segments. Mepyramine (10ˉ⁹M) antagonized contractile responses to HIS. In the presence of 10ˉ⁷M mepyramine, HIS produced dose dependent relaxation of precontracted PIPA and DIPA segments. Cimetidine (10ˉ⁵M) antagonized this relaxation indicating that HIS relaxant effects are mediated by H₂-HIS receptor stimulation in both segments. PIPA segments contracted in response to NE while the DIPA segment responded poorly or not at all suggesting a paucity of alpha adrenoreceptors in distal segments. IsoP produced dose dependent relaxation, that was antagonized by propranolol, of precontracted PIPA and DIPA segments. The dose related contractile response to AA was similar in both PIPA and DIPA segments. These studies indicate that regional differences exist in the response of rabbit IPA to some agonists.

abstract: Master of Science (MS)


title: Effect of individual carbohydrate chains on the in vitro and in vivo biological function of rabbit antithrombin

contributor:
Blajchman, Morris A.
Science

abstract: Antithrombin (AT) is the principal anticoagulant protein that inhibits thrombin and factor Xa in plasma. AT is a glycoprotein with a molecular weight of 58 KDa and contains four consensus sequences for N-linked glycosylation, located at Asn 96, Asn 135, Asn 155, and Asn 192. To investigate the effect of individual glycan side chain on the biological function of AT, each of the four Asn residue sites of glycosylation was mutated to Gln to block glycosylation at these sites. The resulting constructs were initially expressed in COS cells. Permanent cell lines were generated by transfecting CHO cells with the constructs, encoding either the wild-type rabbit AT (AT-WT) or one of the four underglycosylated mutant variants (AT-N96Q, AT-N135Q, AT-N155Q, and AT-N155Q. The results demonstrated that neither the amount of AT secreted nor the kinetics of secretion differed significantly between cell lines expressing AT-WT and any of the mutant AT variants. Purification and radioiodination of AT-WT and each of the four mutant variants permitted pharmacokinetic analysis of their individual catabolism in rabbits. The rate constants for protein catabolism were significantly higher for underglycosylated mutant variants than that of AT-WT. However, no significant difference was identified among the catabolic half-lives of the underglycosylated mutant variants. These results suggest that the extent of glycosylation is more important than its location for determining AT catabolism in vivo. Further in vivo studies of double and triple underglycosylated forms of AT as well as totally deglycosylated AT are needed before a final conclusion can be made. The AT-WT and all forms of mutant variants were capable of forming complexes with thrombin. However, compared with AT-WT, the second order rate constant was significantly reduced for the AT-N 155Q variant, by 2 and 20 fold in the absence and presence of heparin, respectively. No statistically significant differences in second order rate constant were observed between AT-WT and other three underglycosylated variants, AT-N96Q, AT-N135Q, and AT-N192Q. These results suggest that a failure to glycosylate Asn 155 in AT results in reduction of its ability to inhibit thrombin. In comparison with AT-WT, AT-N135Q and AT-N192Q appeared to have slightly higher heparin affinity, but no statistically significant difference was identified. The AT-N96Q showed a small increase in Kd. Compared with AT-WT, however, there was significant reduction in heparin affinity for AT-N155Q (6-fold increase in Kd). These results suggest that a failure to glycosylate Asn 155 in AT results in significant reduction of its ability to bind to heparin.

abstract: Doctor of Philosophy (PhD)


title: Activation of Platelet Adenylate Cyclase by 2-Azidoadenosine: A Potential Photoaffinity Label

contributor:
Haslam, R.J.
Medical Sciences

subject:
Medical Sciences
Medical Sciences

abstract:
2-Azidoadenosine has previously been shown to be a potent activator of adenylate cyclase in human platelet particulate fractions. In the present study, the activation of adenylate cyclase was enhanced by: (a) reducing Mg²⁺ concentration in the assay mixture, (b) adding excess adenosine deaminase during the incubation, and (c) using rabbit platelets instead of human platelets. Under these optimal conditions a 200% increase in adenylate cyclase activity was achieved with 10 μM 2-azidoadenosine.

2-Azidoadenosine was stable in aqueous buffer systems in the absence of light. At pH 7.4, 2-azidoadenosine exists as two tautomers, the azide form and the tetrazole form which were shown to interconvert in a first order fashion with a half-life of 15.3 min at 22°C. These two tautomers appear to be equipotent in their activation of platelet particulate fraction adenylate cyclase. However, on irradiation at 313 nm only the azide form appears to be photolysed to a mixture of products, presumably via a nitrene intermediate.

Although the photolysis of 2-azidoadenosine in the presence of platelet particulate fraction produced activation of platelet adenylate cyclase, evidence was obtained that this was not the result of photoaffinity labeling. The individual effects of pre-exposure to 2-azidoadenosine and irradiation at 313 nm were additive.

Activation of adenylate cyclase by 2-azidoadenosine added to the enzyme assay was reduced if the particulate fraction had been exposed to UV radiation. The same reduction in activation by 2-azidoadenosine added to the assay was seen when the prior irradiation of the enzyme was carried out in the presence of 2-azidoadenosine.

The ³H covalently bound to the platelet particulate fraction upon irradiation in the presence of 2-azido[³H] adenosine was shown to be radiation dependent. However, pre-irradiation of 2-azido-[³H] adenosine generated a product that covalenty labeled platelet particulate fraction as effectively as irradiation of 2-azido[³H]-adenosine in the presence of particulate fraction. This indicates that affinity labeling rather than photoaffinity labeling had occurred. Some inhibition of this labeling was produced by the addition of unlabeled 2-azidoadenosine, 2-chloroadenosine and theophylline. However, neither adenosine nor N⁶-cyclohexyladenosine caused inhibition of labeling when present during photolysis, suggesting that adenosine receptors were not detected. Inhibition of labeling by dipyridamole and coformycin suggested reactions with adenosine transport proteins and adenosine deaminase, respectively. Further studies with various combinations of ligands are required to determine the nature of sites labeled by the photolysis products of 2-azido[³H]adenosine.

abstract: Master of Science (MS)


title: The Gait of Adolescent Males with Autistic Behaviors: A Pilot Study

contributor:
Stratford, Paul
Health Care Practice

abstract: The manner by which a person walks provides information about the functioning of the nervous system. Information of this type may be useful in the determination of the etiology(s) and management of autism. The primary purpose of this pilot study was to determine whether a difference existed between a group of four adolescent males with autism and a group of three normal male adolescents in 17 parameters of gait studied. A secondary purpose of the inquiry was to test a method of collecting and extracting data on temporal-spacial, linear, angular and qualitative gait parameters through the use of a videotaping/data extraction technique. Markers were placed on specific sites on the subjects' body to enable the measurement of joint angles. The subjects were then video taped while they walked up and down a walkway for a total of six times. Data was extracted from the videotape for 15 of the parameters studied. A footprint paper technique was used to collect data on two gait parameters. All data was extracted from the videotape by the investigator. In order to assess a sample of the intrarater reliability of the outcome measures, the investigator extracted data for two of the gait parameters studied on two occasions. Results indicate that the intrarater reliability was excellent for the sample of outcomes measured. Student t-test and chi square analysis revealled no statistically significant differences between the two groups in the 17 gait parameters studied. Clinical significance was found for the knee angle in the initial contact position, alternate arm swing and head position parameters. A Repeated Measures Analysis of Variance (1 factor) analysis showed no significant differences between the two study groups in the symmetry of right and left leg gait parameters. However, the likelihood of detecting a difference should one have existed, is limited due to the small sample size and the limitations and biases operative in study. Therefore, no definitive conclusion can be drawn concerning the differences in the gaits of the groups studied. Modifications to this study are suggested which may enable future research to answer the study question.

abstract: Master of Health Sciences (MSc)


title: Partial Response Signaling with a Maximum Likelihood Sequence Estimation Receiver

contributor:
Anderson, J.B.
Electrical and Computer Engineering

abstract: This thesis evaluates a bandwidth efficient data transmitting system which is modelled as a PRS system. A maximum likelihood receiver implementing VA is assumed at the receiving end. An algorithm is developed to compute a fundamental performance parameter of the system, called the free distance. 99% energy bandwidth and intersymbol interference (lSI) degradation are used to measure the performance of the system. Nonlinear programming and minimax methods are applied to find the optimal channel codes under different criteria. Three different sets of optimal channel codes have been found; first, the worst-case channel codes in terms of lSI degradation, secondly, the minimum 99% energy bandwidth channel codes and finally the minimum 99% energy bandwidth channel with fixed lSI degradation constraint. Two PRS systems with different pulse shaping filter are considered. First, an ideal low pass filter with minimum Nyquist bandwidth is evaluated for channel lengths up to twelve. Then a spectral raised-cosine filter with roll-off factor equal to one is evaluated for channel lengths up to four. The two PRS systems show that a longer channel can have better performance in consideration of both bandwidth and lSI degradation. The raised cosine filter causes no performance penalty in narrow band channels.

abstract: Master of Engineering (ME)


title: Centre of Rigidity Concept and its Application to the Static and Dynamic Analysis of Multi-Story Buildings

contributor: Civil Engineering and Engineering Mechanics

subject:
Civil Engineering
Engineering Mechanics
Civil Engineering

abstract:
The object of this investigation is to establish a method of determining the locus of centres of rigidity of an asymmetric multi-story building structure, which can be applied to determine, with acceptable accuracy, the shear forces in the load-resisting panels in a static or dynamic analysis.

Based on a more general definition for the centre of rigidity within a particular story of a multi-story building structure, a method is developed for the evaluation of the locus of centres of rigidity of a multi-story building structure. Other existing methods are also discussed. It has been found that the locus of centres of rigidity is not only a function of the structural properties but also a function of the distribution of lateral forces acting on the multi-story building structure. It has also been shown that for a building structure consisting of panels which are disproportional in stiffness, the traditional method (in which only the structural elements in an isolated story is considered for the determination of the centre of rigidity within that story) do not give a satisfactory estimation of the locus of centres of rigidity.

The applicability of the locus of centres of rigidity to the evaluation of the shear forces in the load-resisting panels in a static, analysis is investigated. Based on the results of this investigation, methods of determining the panel shear forces in a static analysis are recommended for various types of building structures.

The applicability of the locus of centres of rigidity to the evaluation of the panel shear forces in a dynamic analysis using a three degree-of-freedom model is also studied. The results of this study show that the distribution of the panel shear forces in a frame building structure obtained by using the model, agrees well with that obtained by using a three-dimensional dynamic frame program. The model can only provide a rough estimation of the magnitude of the panel shear forces.

abstract: Master of Engineering (ME)


title: ...sed proelia virgo Heroism and Death in Aeneid Eleven

contributor:
McKay, A.G.
Latin

subject:
Arts and Humanities
Arts and Humanities

abstract:
The main points treated in this thesis may be summarised as follows:

A study of Camilla indicating her ambivalent nature, her androgynous character and her Amazonian aspect which would consequently appear to be uppermost. Upon a detailed examination, Vergil's Volscian queen would seem to have been composed from various sources in Greek and Italic folklore and history:--Harpalyce, Atalanta, Medea, Cloelia, the various Valeriae, Dido, Amata and, in Vergil's own age, Cleopatra.

In order to evaluate the character of Camilla it was necessary to examine heroism and death in other books of the Aeneid in order to introduce comparable behaviour of other heroes for an eventual assessment of character and values. When treating death and funeral rites one needed also to try and trace Vergil's sourced which were Greek, Etruscan and Roman.

These findings, together with the dramatic, ritualistic and colourful language of the text would seem to be indicative of Vergil's interests and feelings, his dislikes and reservations, and suggest some possible conclusions.

abstract: Master of Arts (MA)


title: Optimization of machining strategy and process planning of complex geometry

contributor:
Elbestawi, M. A.
Mechanical Engineering

abstract: Advances in the aerospace and automotive industry have led to the introduction of many new shapes with complex geometries. These shapes are typical of turbine blades, as well as molds and dies. The manufacturing of these geometries consists of automatic tool path generation for multi-axis computer numerically-controlled machining centers. The conformity of the manufactured geometry to the design requirements depends on several factors. These involve cutting tool selection, positioning of the cutting tool, as well as the avoidance of collision and gouging between the cutting tool and the workpiece. This dissertation presents a solid modeling-based approach for tool geometry selection, the simulation and optimization of five-axis tool path generation, as well as gouge and collision avoidance for manufacturing sculptured surfaces. A methodology for tool path generation and checking for the flank-milling of operation is also developed. An optimization algorithm is developed to re-distribute tool path points according to their effect on the geometry of the manufactured surface. A new algorithm to determine tool inclination is also developed based on an effective tool profile and curvature matching techniques. A cusp height control approach is developed based on feasible tool inclinations, and step-over distance evaluation. An algorithm for tool path generation and gouge as well as collision avoidance is developed. A flank milling tool path planning and checking algorithm is developed based on the optimization of the tool path advancement scheme according to the surface topology. A new multi-stage tool model refinement approach was developed, and integrated with the algorithms that constitute this work. Experimental validation of the presented algorithms is carried out to test the cusp height, and smoothness of the tool orientation transition. A comparison between the presented algorithms and state of the art CAM commercial software is also presented. The validation results showed that the developed approach can give more accurate results. The results of this work are intended to fill the shortcomings encountered in the previous research on five-axis machining of sculptured surfaces. These are: cutting tool selection; tool path points optimization, cusp height control, tool position and orientation optimization, and flank-milling.

abstract: Doctor of Philosophy (PhD)