title: The religious factor in Canadian political life: An application of reference group theory

contributor:
Levitt, C.H.
Sociology

subject: Sociology Sociology

abstract: This thesis endeavours to assess the significance of religion to the shaping of political attitudes and behaviour in contemporary Canadian society. Positing a value-additive theoretical model, based on an extension of the reference group concept to preference and deference dimensions, the study links religious identity anchorage to comparative, normative and perspectival reference functions. Utilizing the 1984 Canadian National Election Study data, empirical propositions derived from the value-additive model are tested. The findings indicate that, generally, religion as operationalized by nominal religious preference is a stronger predictor of political values than religious reference group attendance and self-perceived religious identity. Moreover, a value-additive model incorporating a number of the religious dimensions, has limited applicability to the explanation of religion's role in the development of political attitudes and behavioural configurations. However, the findings suggest that nominal religious affiliation tends to function as an organizing perspective, through which the political world is viewed. The persistence of religious affiliation after controls for attendance and self-perceived religiosity, tends to indicate that the perspectival function of affiliation is as much an issue of socio-religious heritage, as it is of present religious engagement. The Weberian assumption of religious preference types that breed distinct orientations to the social world is confirmed in this research. Additionally, the variation on political life matters for religious affiliate types is considered by the group's position of dominance or nondominance in the Canadian social system. Also, a theory of the Religious None as reflective of noninstitutionalized identity is developed, in accord with the findings.

abstract: Doctor of Philosophy (PhD)


title: The role of oxygen in hot metal desulphurization with calcium carbide powder injection

contributor:
Irons, G.A.
Materials Science and Engineering

subject:
Materials Science and Engineering
Materials Science and Engineering

abstract: It has been appreciated for some time that low oxygen activity is required for effective steel desulphurization, and recently this has been recognized for hot metal desulphurization. In the present experiments, calcium carbide was injected into 70 kg melts of iron during which desulphurization and deoxidation were studied by continuously measuring oxygen activity and frequently sampling for sulphur content. In some experiments, carbon dioxide was used either as a carrier gas or as generated from calcium carbide/limestone mixtures. The experiments confirmed that the oxygen activity in hot metal was controlled by the silicon-silica equilibrium, except when aluminum was added. It was found that the rate of desulphurization was associated with the oxygen activity. The desulphurization rate increased as oxygen activities decreased in order from carbon dioxide-containing injections into iron-carbon-silicon melts, to calcium carbide/nitrogen injections into iron-carbon-silicon melts, to finally calcium carbide/nitrogen injected into iron-carbon-aluminum melts. The dependence of the incubation period with the melt oxygen activity was recognized. The incubation times coincide with periods of deoxidation before desulphurization proceeds. In order to interpret the experimental results, a kinetic model was developed that takes simultaneous desulphurization and deoxidation into account. This model demonstrates clearly that the rate of desulphurization is controlled by the melt oxygen activity and the powder feed rate. Thus, low oxygen is required for effective hot metal desulphurization. In a log h$\sb{\rm o}$-log h$\sb{\rm s}$ diagram, the refining trajectories determined from the kinetic model were found to be consistent with those obtained from the experiments. From the model calculations, it was found that the commercial calcium carbide which normally contains 30 per cent of lime can be employed for the melts pre-deoxidized with silicon or aluminum, without causing significant delay of desulphurization. Another aspect of this work is the particle-liquid contact. The contact was measured by monitoring the melt temperature during injection, and applying calorimetric principles to analyze the results. It was found that a significant fraction of particles does not come in contact with the melt during their rise through it. The particle-liquid contact fraction is approximately 30-50 per cent. The same conclusion was obtained by analyzing the experimental rate constants of desulphurization on the basis of mass transfer theory.

abstract: Doctor of Philosophy (PhD)


title: Inhibition of platelet and vascular smooth muscle function by cyclic nucleotides: Synergism between activators of adenylyl and guanylyl cyclases

contributor:
Haslam, Richard J.
Medical Sciences

subject:
Medical Sciences
Medical Sciences

abstract: In platelets, the activators of guanylyl cyclase used were sodium nitroprusside (SNP) and SIN-1 (the active metabolite of molsidomine). PGE$\sb1,$ a functional analogue of prostacyclin (PGI$\sb2),$ and adenosine were the activators of platelet adenylyl cyclase studied. Changes in cyclic ($\sp3$H) nucleotides were measured in platelets prelabelled with ($\sp3$H) guanine and ($\sp3$H) adenine. Incubation of labelled platelets with SNP or SIN-1 caused inhibitions of platelet function which were associated with large dose-dependent increases in ($\sp3$H) cGMP and 1.4 to 3.0-fold increases in ($\sp3$H) cAMP. However, addition of either SNP or SIN-1 with PGE$\sb1$ or adenosine, at concentrations of the latter that had little effect alone, caused much larger increases in ($\sp3$H) cAMP and greatly enhanced the inhibition of platelet function. Experiments with an adenylyl cyclase inhibitor, 2$\sp\prime,$5$\sp\prime$-dideoxyadenosine (DDA), suggested that these synergistic interactions depend on an enhanced accumulation of cAMP. Hemoglobin inhibited all nitrovasodilator-mediated effects. Cilostamide, a selective inhibitor of platelet cGMP-inhibited cAMP phosphodiesterase (cGI-PDE), had effects identical to those of SNP, suggesting that the actions of the latter depend on inhibition of the same enzyme. Also, the results obtained with M&B 22,948, a cGMP-selective PDE inhibitor, strongly suggest that the increases in platelet ($\sp3$H) cAMP caused by nitrovasodilators, in the presence or absence of activators of adenylyl cyclase, are mediated by the inhibition of cAMP breakdown of cGMP. To determine if a similar synergism is seen in vascular smooth muscle (VSM), the interactions between isoproterenol and either nitrovasodilators or cAMP-PDE inhibitors were studied. A fast and sensitive prelabelling method was established for the measurement of cyclic nucleotides in cultured vascular smooth muscle cells (VSMC) from rat aorta. Using this method, agonist-induced changes in the cyclic nucleotide levels of two different aortic VSMC lines were studied. (Abstract shortened by UMI.)

abstract: Doctor of Philosophy (PhD)


title: Game theory models and their applications in some inventory control and new product management problems

contributor:
Parlar, Mahmut
Cheung, Sherman
Yuan, Yufei
Management Science/Systems

subject:
Management Science/Systems
Management Information Systems
Management Information Systems

abstract: This thesis deals with game theory and its applications in management science and focuses upon some management science areas such as inventory control and new product development. Some interesting theoretical findings and new policies are obtained by using the game theoretical approach to analyze certain management science problems. The discussion starts with a review of static game theory models and their applications in management science. Of particular interest here is the state of the art of game theory as an analytical technique in management science. Chapters Two and Three discuss the discount problem. Particular attention is paid to the gaming nature and the buyer's demand aspect of the problem. It is shown that, if they work independently and rationally, the seller and the buyer can gain from price discount only if it can attract more demand from the buyer. Nevertheless, they can gain from quantity discount even if demand is constant. Quantity discount is always better than a price discount for the seller and, in certain situations, can be very efficient in obtaining the maximum profit. Optimal decisions are obtained for both the seller and the buyer under various conditions. Chapter Four studies the order quantities of substitutable products with stochastic demands. This analysis extends the newsboy problem analysis into situations with three or more players. It is shown that there is one Nash equilibrium for the problem. If any player(s) acts irrationally, the other players' decision problem reduces to the one without the irrational player(s). If cooperation is possible, their decisions depend on whether side payments are allowed. If side payments are allowed, they will determine their order quantities together. If side payments are not allowed, secure strategies exist for each player. It is also shown that all players' cooperation is often worthwhile and feasible. Chapter Five analyzes the growth of new repeat purchasing products. It is shown that markets of repeat purchasing products will never saturate like that of consumer durable products unless customers are extremely loyal to at least one product. For new repeat purchasing products, the optimal advertising strategy is increasing at the introductory stage and then decreasing or possibly terminating after some time and, the optimal service strategy is monotonically increasing at the introductory stage and then possibly maintained constant at a certain level. Especially, more advertising should be done at early stages against competitors' advertising campaign. The game is solved analytically for optimal strategies in the case where all the control functions representing the effects of advertising and service are linear in the control variables. Finally, the main findings and possible extensions to this research are briefly summarized in Chapter Six. (Abstract shortened by UMI.)

abstract: Doctor of Philosophy (PhD)


title: The effects of migration and remittances on two Lebanese villages

contributor:
Papageorgiou, Y.Y.
Geography

subject: Geography Geography

abstract: This thesis studies the effects of migration and remittances on two villages in south east Lebanon. The human capital theory of migration, and that of migration and remittances which is developed by Stark and Lucas (1985) and Lucas and Stark (1988) constitute the conceptual framework of the research. Data for the thesis were gathered by surveying households in the Muslim village of Lala, and the neighbouring Christian village of Khirbit Kanafar. These data immediately reflect two realities: the internal migration of Khirbit Kanafar residents, and the international emigration of those from Lala. Moreover, remittances to Khirbit Kanafar are almost non-existent and those to Lala are massive. Based on the theoretical synthesis, hypotheses were developed and later tested using three multiple regression models: one for remittances to Lala, and the other two are for the domestic income in each of the villages. A finding from the remittance model supports the theoretical hypothesis that sons in their early years of migration can not and do not remit. Such migrants are likely to face unpredictable job prospects and are usually in need of cash to get established. Once migrant sons are established, remittances to their families of orientation increase and continue to flow (at a slower rate) fifteen or more years after emigration. This reflects not only the apparent permanency of migrant sons' commitment to the insurance contract they struck with their families, but also to a continued sense of altruism towards them. Another finding that concurs with the theory pertains to migrants' rural investments which are facilitated by residual family members and is argued here to be mutually beneficial. Altruism emerges to be a greater motivation for remittances than self-interest and a familial insurance-type contract, a finding that detracts from the theory. Similarly, emigration does not appear to be a family strategy to increase income by adopting new agricultural techniques.

abstract: Doctor of Philosophy (PhD)


title: A virtual finite element method for contact problems

contributor:
Dokainish, M.A.
Mechanical Engineering

subject:
Mechanical Engineering
Mechanical Engineering

abstract: An algorithm is presented for the solution of mechanical contact problems using the displacement based Finite Element Method. The corrections are applied as forces at the global level, together with any corrections for other nonlinearities, without having to nominate either body as target or contactor. The technique requires statically reducing the global stiffness matrices to each degree of freedom involved in contact. Nodal concentrated forces are redistributed as continuous tractions. These tractions are re-integrated over the element domains of the opposing body. This creates a set of virtual elements which are assembled to provide a convenient mesh of the properties of the opposing body no matter what its actual discretizaton into elements. Virtual nodal quantities are used to calculate corrective forces that are optimal to first order. The work also presents a derivation of referential strain tensors. This sheds new light on the updated Lagrangian formulation, gives a complete and correct incremental form for the Lagrangian strain tensor and illustrates the role of the reference configuration and what occurs when it is changed.

abstract: Doctor of Philosophy (PhD)


title: Core excitation of some organometallic and organosilicon molecules

contributor:
Hitchcock, Adam P.
Chemistry

subject: Chemistry Chemistry

abstract: Inner-shell electron energy-loss spectroscopy (ISEELS) is an electron impact technique for the examination of inner-shell excitation of matter in the soft X-ray energy range between 20 and 1000 eV. It has long been utilized to study the core-excitation spectra of atoms and small organic or inorganic molecules. This thesis demonstrates the extension of such investigations to large organometallic complexes and organosilicon compounds in the gas phase. Measured under low momentum transfer conditions (>2.5 keV impact energy and small scattering angle, ≤2∙), where the spectra are dominated by electric-dipole-allowed transitions, ISEELS spectra have been recorded for transition metal carbonyls Fe(CO)₅, Fe₂(CO)₉ and CO₂(CO)x; metallocenes Fe(C₅H₅)₂, CH₂CH-C₅H₄FeC₅H₅, C₄H₉-C₅H₄FeC₅H₅ and Co(C₅H₅)₂; mixed-ligand complexes C₅H₅TiCl₃, C₆H₆Cr(CO)₃, organopolysilanes (CH₃)₃SiSi(CH₃)₃ and Si[Si(CH₃)₃]₄ as well as related compounds TiCl₄, C₅H₆ and (C₅H₆)₂. The spectral features have been assigned on the basis of comparison with the spectra of the free ligands and with a few previous studies of related organometallic/organosilicon species, along with extended Hückel molecular orbital calculations. The spectra provide novel insight into how inner-shell excitation spectroscopy reflects the metal-ligand bonding in these complexes and ligand-ligand interaction via the central metal atom. All the O 1s spectra are similar to each other, and the C 1s and metal 2p spectra of related compounds in a series (e.g., carbonyl complexes or metallocene derivatives) also have a similar shape, suggesting similar origins of the spectral features. Small variations through each series have been interpreted in terms of changes in the electronic structure associated with changing substituents. The metal 2p spectra are found to be surprisingly sensitive to the identity of the ligands present in the complexes and/or the character of the metal-ligand bonding. A resonance associated with the Si-Si σ* antibonding molecular orbital is identified at 102.5 eV in the Si 2p spectra of the two organosilicon compounds.

abstract: Doctor of Philosophy (PhD)


title: Multivariate Identification and Stochastic Control of A Pilot Plant Packed Bed Reactor

contributor:
MacGregor, J.F.
Chemical Engineering

subject:
Chemical Engineering
Chemical Engineering

abstract: The modelling and control of a pilot plant packed bed catalytic reactor is investigated. The reactions considered are those of the hydrogenolysis of n-Butane over a nickel on silica gel catalyst. These involve several independent species and are highly exothermic. A multivariate transfer function model for process and a time series model for the disturbances are constructed through an iterative procedure of process identification, parameter estimation and diagnostic checking. Using exit concentrations inferred from reactor bed temperatures and inlet flow measurements, a multivariate stochastic controller, designed to minimize a quadratic function of the production rates of various intermediate products subject to constraints on the variances of the manipulated input flowrates is implemented on-line using a process minicomputer. The parameters of the inferential concentration equation are updated on-line using infrequent data from a process gas chromatograph. The performance of this feedback controller is found to be quite satisfactory.

abstract: Master of Engineering (ME)


title: Regulation of pineal melatonin production by sex hormones

contributor:
Brown, G.M.
Medical Sciences

subject:
Medical Sciences
Medical Sciences

abstract: The effect of sex hormones on pineal melatonin production has been examined. The diurnal profile in urinary aMT6s excretion, which is believed to represent pineal melatonin production and 24 hour sex hormone excretion was determined by RIA in male and female rats at age of 3 weeks, 2 months, 8 months, 14 months and 20 months. A concomitant decrease in metabolite excretion corrected for body weight was found with increasing age together with a highly significant sex difference in aMT6s output at 3 weeks, 2 months and 8 months of age. Increase of body weight with age is an important factor responsible for the age-related alteration while the difference in sex hormone milieu between male and female animals could be one explanation for the sex difference in aMT6s excretion in younger rats. The effect of castration on the diurnal profile in urinary aMT6s excretion was observed in both male and female rats at 3 weeks, 2 months and 8 months of age. Castration caused a fall in urinary aMT6s excretion in 3 week old female rats but increased the metabolite output in both 2 month and 8 month old female rats. In male rats castration reduced aMT6s excretion at 2 months of age but there was no significant effect at 3 weeks or 8 months of age. In addition, urinary aMT6s excretion varied with the stages of the rat oestrous cycle; the lowest excretion was observed at proestrus corresponding with the highest 24 hour urinary oestradiol excretion. Sex hormone treatment was performed on 2 month old castrated male and female rats. Both testosterone treatment on male castrated rats and oestradiol on female castrated rats abolished the effects of castration on aMT6s excretion. Administration of oestradiol to male rats and testosterone to female rats decreased and increased urinary aMT6s excretion, respectively. Castration had no significant effect on the half life of melatonin elimination from plasma either in 2 month old male and female rats or 6 month old male rats. The effect of castration and sex hormone treatment on the pineal response to isoproterenol (ISO) was also investigated in 2 month and male and female rats. Castration increased aMT6s excretion in female rats but reduced aMT6s output in male animals in both time-course and dose-dependence studies. Changes in serum and pineal melatonin response to ISO with castration and sex hormone treatment were examined by an Elisa. Consistently, castration in female rats increased pineal and serum melatonin responses to ISO and oestradiol treatment to castrated female rats blocked the elevation, whereas in male rats castration decreased the responses and testosterone treatment to castrated male rats abolished the reduction. The effect of sex hormones on pineal beta-adrenergic receptors were studied in 2 month old rats. The beta-adrenergic receptor binding was determined by using $\sp3$H-dihydroalprenolol (DHA) in single pineal glands. Castration in female rats increased the receptor density compared with oestradiol treated and sham-operated animals. By contrast, the receptor concentration in castrated male rats was lower than testosterone treated and sham-operated male animals. The results of the present study demonstrate that sex hormones are involved in the regulation of pineal melatonin production; in 2 month old rats, oestradiol has an inhibitory while testosterone exerts a stimulating effect. The effects do not result from the alteration of circulating melatonin metabolism. One of the mechanisms is that sex hormones alter the pineal response to adrenergic stimulation and act on the pineal beta-adrenergic receptors.

abstract: Doctor of Philosophy (PhD)


title: Estimation of wave directional spectra and applications to the study of surface gravity water waves

contributor:
Tsanis, L.K.
Civil Engineering

subject:
Civil Engineering
Civil Engineering

abstract: This thesis deals with the estimation of wave directional spectra and applications to the study of surface gravity water waves. Theoretical foundations and testing procedures are established to evaluate and compare different methods of extracting the wave directional spectrum from a wave record. An integrated software package for the analysis of directional seas is developed and used to test all methods, and to identify their properties, characteristics and biases. As a result, guidelines for the use of these methods are drawn. The findings indicate that all of the methods currently used for wave directional spectrum estimation have drawbacks. As a result, three new methods are proposed and tested against current methods. Test results indicate that a proposed closed-form of the Maximum Likelihood Method is the best choice, from both a theoretical and computational point of view. The new method was shown to outperform all other estimates for both heave-pitch-roll and wavestaff data. Field data from the Atlantic Ocean, Lake Ontario and Lake St. Clair (spanning two orders of magnitude in size) is investigated in an attempt to demonstrate the resolution potential of the newly developed method of estimating the wave directional spectra. As a result, completely decoupled spectra are observed for the first time in rapidly turning winds, and a clear relationship between the wave relaxation parameter and the wave age is established. Directional spreading parameter values are found to be higher than the established values in previous studies, for both Lake Ontario and Atlantic Ocean data. In addition, the Atlantic Ocean directional spectra are found to be narrower than their Lake Ontario counterpart. Finally, wave measurements in Lake St. Clair indicate that the structure of directional spectra can be very complicated, even in small lakes, and that a strong shear current can cause not only the refraction of an incoming wavefield, but can also inhibit the generation of waves propagating directly against it.

abstract: Doctor of Philosophy (PhD)


title: A geometric and microradiographic study of functional adaptation in the human skeleton

contributor:
Saunders, Shelly R.
Anthropology

subject: Anthropology Anthropology

abstract: Continuing Periosteal Apposition (CPA) refers to recent lamellar bone formation on the external surface of the mature skeleton. CPA is most often viewed as mechanical compensation, a form of functional adaptation in the event of overstrain pursuant either to high levels of physical activity, or to prior endosteal bone resorption and increased endocortical porosity. The theoretical basis for this expectation derives primarily from Frost's Mechanostat, describing the relationship of bone surfaces and bone cellular activity in response to changes in the functional strain environment. An objective of the study was to ascertain how CPA might be associated with structural (geometric) properties characterizing entire cross-sections (areas and moments of area), as well as with proximate histological variables, such as intracortical porosity and mean bone age. The latter variable is derived from a mathematical model developed in this study, which provides an index of intracortical remodelling 'history'. Left and right second metacarpals, and the left second metatarsal, obtained from medical school cadavers (n = 89 bones) and a small EuroCanadian historic cemetery (n = 21 bones) comprised the sample for this study; the majority were male, and over 50 years of age. Cross-sectional geometric properties indicative of structural strength were measured from three sections prepared from each element, one at midshaft and two from the distal diaphysis; a subsample was microradiographed for histological evaluation at four locations within each cross-section. Although not without exception, the directional asymmetries identified between the various structural and histological variables: (1) tend to reflect presumed functional strain inequities pertaining to side (e.g., right > left), gender (male > female), age (young > old). The presumed inequity for 'lifestyle' (historic > cadaver) was not supported; (2) support the conclusion that CPA constitutes a component of functional adaptation in the skeleton and may act as mechanical compensation; and (3) support the Mechanostat as an interpretive framework for skeletal biological analyses.

abstract: Doctor of Philosophy (PhD)


title: Adaptive tracking in feedback linearizable systems

contributor:
Sinha, Naresh K.
Electrical Engineering

subject:
Electrical and Computer Engineering
Electrical and Computer Engineering

abstract: This thesis investigates the problem of adaptive control for a class of nonlinear systems which are explicitly linearizable by nonlinear state feedback. A theoretical framework and a systematic design procedure have been established for adaptive control of feedback linearizable systems with parametric and dynamic uncertainties. An error model for adaptive tracking problem is introduced for the first time considering both the parametric and dynamic uncertainties. The significance of the error model lies its explicit physical meanings. It can serve as a basis for the development of adaptive strategies and control algorithms for feedback linearizable systems. Four new adaptive algorithms have been proposed. The stability and parameter convergence of these algorithms are theoretically established by using two different approaches. The robustness of the algorithms for adaptive regulation problem has been analyzed. The tracking ability and effect of initial parameter estimates have been studied also. The restrictive matching conditions and nonlinearity growth conditions are two of the main problems appearing in literature of adaptive control for nonlinear systems. The two problems have been solved here for the first time. A Model Reference Adaptive Control algorithm and an Augmented Error Control algorithm have been presented to remove these restrictive limitations. The class of nonlinear systems for which adaptive control can be applied has been substantially enlarged. A comparison between adaptive control schemes and nonadaptive control schemes has been made. The results of comparison show that the performance of adaptive controllers is superior to that of nonadaptive state feedback controllers. A decentralized adaptive control strategy is introduced for nonlinear systems. It has been shown that a decentralized adaptive control system is much easier to implement than a centralized control system and is more robust to structural disturbance. To demonstrate practical applications, the proposed adaptive control algorithms have been applied to the control problems of a class of robotic manipulators. Three different types of adaptive tracking problems of manipulator systems have been investigated. The results of simulations demonstrate considerable improvements in tracking accuracy over the traditional inverse dynamics control methods in the presence of significant parametric uncertainty.

abstract: Doctor of Philosophy (PhD)


title: Artificial intelligence applied to bridge deck radar interpretation

contributor:
Poehlman, W.F.S.
Electrical Engineering

abstract: The use of ground probing radar for the nondestructive evaluation of structures has been in use for more than a decade. Through the examination of the subsurface reflection waveforms, determinations may be made regarding the profile geometry as well as detecting the presence of structural faults undetectable from surface inspections. Although automated systems have been previously created, the arduous task of interpretation of the large volumes of data produced by these radar surveys are still best handled by human experts. The research presented in this dissertation details the development of novel techniques which allow an Artificial Intelligence based system to demonstrate comprehensive structural and fault analysis capabilities. Development of an autonomously defined and system trained neural network based radar waveform filter allows reflection event feature extraction. The three-dimensional concept of the bridge structures and the system's ability to accurately model the diverse cross-sections are combined with the neural preprocessed data to allow data abstraction. The positional relationship present in bridge radar surveys are exploited to develop a unique spatiotemporal foundation for analysis. The comprehensive expert system was tested with real bridge radar data and the system results correlate well with human expert analysis.

abstract: Doctor of Philosophy (PhD)


title: Seismic analysis of multiply-supported MDOF secondary systems

contributor: Civil Engineering and Engineering Mechanics

subject:
Engineering Mechanics
Civil Engineering
Other Engineering
Civil Engineering

abstract: The decoupled seismic analysis of Multi-Degree-Of-Freedom (MDOF) secondary system subjected to multiple-support excitations overestimates its response. It is recognized that the analysis overestimates the secondary system response because the dynamic characteristics of the combined Primary-Secondary (P-S) system are neglected. The problem that is addressed in this thesis is how to include the effects of these dynamic characteristics in decoupled seismic analyses of multiply-supported MDOF secondary systems. The objective is to estimate the secondary system response using a decoupled seismic analysis such that it approximates the response that would have been obtained using a coupled analysis. Three approaches are considered in addressing the problem. These are the conventional deterministic approach, the recently developed Cross-Cross-Floor-Spectrum (CCFS) approach, and the stochastic approach. Three major contributions are achieved. First, the complexity associated with the seismic analysis of multiply-supported MDOF secondary systems is highlighted. Second, an improved CCFS approach, that avoids the shortcomings of the original CCFS approach, is proposed. Third, a new stochastic approach, that accounts for the dynamic characteristics of the combined P-S system, is developed.

abstract: Doctor of Philosophy (PhD)


title: A mass spectrometric examination of some carbohydrates

contributor:
MacLean, D.B.
Chemistry

subject: Chemistry Chemistry

abstract: Many carbohydrates have useful biological properties, which has generated interest in the structural elucidation of this class of compounds. One technique that has been applied successfully to the structural elucidation of carbohydrates and carbohydrate derivatives is mass spectrometry (MS). In this research a number of peracetylated and pertrideuteroacetylated mono- and disaccharides were examined by ammonia desorption chemical ionization (NH₃-DCI) in order to gain insight into the fragmentation processes and to assess the structural information available in the NH₃-DCI mass spectra. As a result of these studies a new method has been developed to determine the position of linkage in peracetylated disaccharides comprised of hexopyranose (glucose or mannose) units by use of mass-analyzed ion kinetic energy (MIKE) scans. The second part of this thesis deals with the structural elucidation of the core portion (core) of the lipopolysaccharides (LPS) derived from two mutants (AK1012 and AK1401) of the bacterium Pseudomonas aeruginosa, a ubiquitous opportunistic pathogen, which is resistant to antibiotic therapy. Since LPS are the principal antigenic determinants of this bacterium a knowledge of the structure of the LPS is important in the development of synthetic vaccines. In this work mass spectrometry, in conjunction with a number of chemical and chromatographic techniques, was applied to the structural elucidation of the AK1012 core and AK1401 core. The combination of methods applied to this problem resulted in the elucidation of many of the structural features of these carbohydrates; however, some aspects of the structure remain unknown.

abstract: Doctor of Philosophy (PhD)


title: The optical properties of R titanium oxides perovskites (R = lanthanum, cerium, praesodymium, neodymium, samarium, gadolinium)

contributor:
Timusk, T.
Physics

subject: Physics Physics

abstract: Reflectance spectroscopy (50-40000 cm⁻¹) has been used to study the rare earth titanium (III) oxides (RTiO\sb3$, R = La, Ce, Pr, Nd, Sm, Gd). A mid-infrared absorption has been observed in all members of the series. With decreasing rare earth radius (and decreasing Ti-O-Ti bond angle) the band shifts to higher frequencies. A tight-binding calculation of the effect of the Ti-O-Ti bond angle on the conduction band width supports the picture in which the mid-infrared band is due to transition from the lower Hubbard to the upper Hubbard band. Because this intrinsic absorption is at lower energy than transitions corresponding to O(2p)-Ti(3d) charge transfer (≈ 4 eV) the rare earth titanites are classified as Mott-Hubbard insulators. Systematic variations in the infrared active phonon spectra were observed and related to a tetragonal distortion of the TiO₆ octahedron in NdTiO₃, SmTiO₃ and GdTiO₃. In a second study, the reflectance of four well characterized (x-ray, neutron activation, thermogravimetric, dc resistivity, magnetization) doped LaTiO₃ samples was measured. Although the starting materials contained equimolar amounts of La and Ti, the neutron activation results and structural considerations indicate the presence of La vacancies. There is a transfer of oscillator strength from the mid-infrared band to lower frequencies in highly doped samples but transitions placing two electrons on one site (from the lower to the upper Hubbard band) retain considerable oscillator strength even in a sample where approximately one-fifth of the sites are empty.

abstract: Doctor of Philosophy (PhD)


title: Cholecystokinin in the central nervous system: Pharmacological characterization, solubilization, and autoradiographic localization of the receptors and interactions with central dopaminergic functions

contributor:
Mishra, Ram K.
Medical Sciences, Neurosciences

subject:
Medical Sciences
Neurosciences
Medical Sciences

abstract: In 1980, cholecystokinin (CCK) was demonstrated to co-exist with dopamine (DA) in certain neurons of the CNS. Since the animal studies were carried out on rodents, little was known about CCK in the brain of higher mammalian species. In the present study, CCK receptors were characterized in the brains of higher mammalian species. The pharmacological characteristics of CCK receptors appear to have been well preserved in the mammalian brain. However, marked differences in the distribution of CCK receptors were observed in several brain areas. There were basically two main types of species-specific differences. The absence or presence of CCK receptors in a given structure and differences in the distribution within a given structure. Although the reasons for such species-specific differences in receptor distribution are not clear at the present time, this evidence cautions against simple extrapolation of data obtained in animal models directly to clinical applications. Moreover, although some animals studies provided evidence of an inhibitory effect of CCK on DA function, which would be compatible with a potential antischizophrenic action, others reported a lack of modulation or an enhancement of DA function. Circling behaviour is commonly used to assess DA function. In the present study, unilateral intracranial microinjections of CCK₈ induced a dose-dependent contraversive circling bias in rats. This CCK₈-induced contraversive circling bias was attenuated by the DA receptor antagonist haloperidol. To further elucidate the mechanism(s) underlying this CCK-induced circling behaviour, the effects of CCK peptides on ligand binding at DA receptors and on DA-stimulated adenylate cyclase were investigated in the rat striatum. Under the assay conditions employed, CCK₈ has no significant acute effects on binding at the DA receptor or on DA-stimulated adenylate cyclase. It is possible that CCK induced its acute facilitatory influence on DA function in the circling behaviour paradigm by altering DA turnover or release. Another problem with the animal studies which were used as the basis for the clinical application was that the vast majority were of an acute nature. In the present study, long-term administration of CCK₈ did not significantly alter DA D₂ receptor densities nor the expression of DA D₂ receptor mRNA. In contrast, long-term haloperidol administrations significantly increased CCK binding in the nucleus accumbens, olfactory tubercle, and frontal cortex. (Abstract shortened by UMI.)

abstract: Doctor of Philosophy (PhD)


title: Low strain behaviour of a particulate-reinforced aluminum alloy

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

abstract: The primary purpose of this investigation was to examine the strengthening that arises when reinforcing an aluminum alloy with approximately equiaxed shaped SiC particles. The results indicate that the majority of strengthening that is derived from the particles develops at low strains. For a variety of test conditions explored, about 90% of the total strengthening derived is developed by a plastic strain of about.5%. This is primarily a result of the high strain hardening rate which is exhibit by the composite materials during the onset of plastic flow. An examination of the Bauschinger effect in the composites indicates that an internal stress, resulting from inhomogeneous plastic flow, develops rapidly in the low strain regime. Microstructural observations suggest that the nature of this inhomogeneous plastic flow is influenced by the distribution of the SiC particles. Initial plasticity appears to be associated with regions of the microstructure which are relatively particle free. A self-consistent model, based on Eshelby's equivalent inclusion method, has been developed which is capable of calculating the stress partitioning which occurs between the Al matrix and SiC particles during the elastic/plastic transition and beyond. Excellent quantitative agreement between the experimentally measured elastic modulus and that predicted by the model was achieved. When considering a uniform distribution of second phase particles, the model predicts an increase in the initial strain hardening rate. However, it underestimates the actual strain hardening rate which was measured experimentally. The influence of particle distribution was examined by representing the composite microstructure by a bimodal mixture consisting of a particle rich and particle free phase. The model predicts an increase in the initial strain hardening rate as a result of clustering the microstructure in this way. The magnitude of this increased hardening is comparable to that measured experimentally.

abstract: Doctor of Philosophy (PhD)


title: A framework for testing the learning of cognition-based human-computer interfaces

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

subject: Management Sciences/ Systems

subject: Management Information Systems

subject: Management Sciences and Quantitative Methods

subject: Management Information Systems

abstract: Successful implementation of Information Systems requires user acceptance. The old approach of adapting users to the system is no longer acceptable as more middle and senior professionals and managers are becoming system users. Due to the increasing people cost component of systems implementation, there has been a recognition that the human-computer interface must be easier to learn to use and recall for the individual who is both a novice and discretionary computer user. From the cognitive psychology literature, various principles can be applied to the interface design to improve learning and recall. These principles can be used by interface designers to improve the usability of the human-computer interface. Models of human-computer interaction have been devised by other researchers. However, to date there has been little available in the way of satisfactory methodologies or tools to allow designers to measure practically how an interface implementation performs with respect to both learnability and subsequent recall. This thesis develops a framework for testing human-computer interface learning. The framework differs from previous attempts in that it defines a new criteria for quantifying human-computer learning and recall, as well as providing a simple and effective tool for use by designers to determine such learnability metrics during the design process. In order to demonstrate the usefulness of the framework, it is used to experimentally test an original prototype interface design which attempts to improve human learning speed and memory retention using elaborative learning techniques and the "generation effect". The framework was able to measure significant differences between interfaces with respect to recall performance, and has demonstrated its utility as a contribution to the field of interface usability evaluation.

abstract: Doctor of Philosophy (PhD)


title: Salt film development during pitting of nickel

contributor:
Ives, M. B.
Materials Engineering

abstract: Pitting corrosion is one of the major causes of industrial failure of metallic parts. Unfortunately, such attack cannot always be detected before perforation occurs. Understanding the mechanism of pit development will provide us with a clue of how to prevent pitting corrosion in advance. From an engineering point of view, it is important to keep the pit, once it forms, repassivated rather than allow continuous growth, leading to the perforation. The key factors controlling pit development must therefore be determined. A comprehensive model of pitting processes is proposed which considers interfacial dissolution, salt film formation, multiple species in solution, reaction equilibria, migration and diffusion. The model is capable of determining local chemistry within pits and characterizing the conditions necessary for stabilization of pitting corrosion. The model is experimentally verified using microelectrodes developed to measure the local properties of pitting sites. The electrodes were characterized through studies on their potential stability, spatial resolution, and the interference of other ions involved in the corrosion of nickel. The study was performed on a nickel model pit in a saline environment. The in situ measurements obtained by microelectrodes provide the direct evidence of existence of a salt layer, comprised of corrosion products, at the bottom of a developing pit. The condition for formation of the salt film in active pits appears to require that the pit depth be sufficient to ensure the maintenance of a critical local solution chemistry. The experimental results are consistent with the theoretically predicted critical depth at which a metal chloride salt layer starts to form at the pit bottom. The measurements of the potential distribution within the salt film have provided data for the potential drop across the salt film, its thickness and therefore its conductivity. These help us to achieve a better understanding of the nature of the salt film. The anodic behaviour of nickel was studied in solutions which simulate the pit electrolyte, based on the in situ measurements of the local pH and chloride ion concentration within a pit at different stages of development. The factors controlling the pit growth were deduced.

abstract: Doctor of Philosophy (PhD)


title: Sterically hindered chiral organometallic complexes: An X-ray crystallographic, NMR spectroscopic and EHMO study

contributor:
McGlinchey, M. J.
Chemistry

subject: Chemistry Chemistry

abstract: Sterically crowded organometallic complexes present fascinating problems of structure and molecular dynamics. Tetrahedral clusters such as (RC≡CR')−(C₅H₅)₂M₂(CO)₄, where M = Mo or W, crystallize in conformations possessing three terminal carbonyls while the fourth is semi-bridging. However, these ligands undergo a rapid exchange process which can be followed by variable-temperature NMR spectroscopy. When the R substituent is derived from a chiral natural product, the low temperature NMR spectra reveal the presence of diastereomers which are interconvertible via rotations of the organometallic vertices. The fluxional behaviour of tetrahedral clusters containing such vertices as Co(CO)₃, Fe(CO)₃ or (C₅H₅)Mo(CO)₂ can be rationalized by means of molecular orbital calculations at the extended Huckel level of approximation. These studies show that the barriers to vertex rotation can usually be traced to one principal orbital interaction in each case. However, in (C₅H₅)₂Mo₂(CO)₄(R-C≡C-R') clusters, the barriers are primarily steric in character. The ability of transition metal clusters to delocalize electronic charge is well known and, in principle, could be used to stabilize intermediates of biochemical significance. Treatment of 2-methylcyclopentanone with an alkyne anion was carried out in order to generate 1-alkynyl-2-methylcyclopentanols in which the methyl and alkynyl groups are trans diaxial; the aim was to mimic the "D"-ring of the steroidal contraceptive mestranol. In fact, the major epimer was the one in which the methyl and alkynyl substituents were disposed in a cis manner. The conformation of 2-methyl-1-phenylethynylcyclopentanol 47 was elucidated by two-dimensional NMR techniques. Moreover, the structure of 47 and also of its Co₂(CO)₆ derivative have been determined crystallographically. Protonation of the dicobalt or dimolybdenum complexes of 47 lead to stable cations; treatment of these cations with nucleophiles results in elimination of water to yield 2-methylcyclopentene derivatives of which the dimolybdenum cluster has been characterized by x-ray crystallography. The sterically crowded complexes (C₆H₅)₃SiOH[Cr(CO)₃]n, where n = 1,2,3, have also been characterized X-ray crystallographically and all three have propellor-type geometries. The question of whether the phenyl ring rotations are correlated has been studied by variable-temperature NMR spectroscopy. These systems do not yield stable silicenium cations, but the analogous Cr(CO)₃ complex of triphenylcarbinol not only shows fluxional behaviour but also yields a metal-stabilized cation. The pathway for phenyl rotations in such systems can be followed via a Dunitz-type trajectory approach in which a number of x-ray structures were analyzed.

abstract: Doctor of Philosophy (PhD)


title: Agricultural change and common land in Cumberland, 1700-1850

contributor:
Gentilcore, Louis R.
Geography

subject: Geography Geography

abstract: Traditionally, the eighteenth and early nineteenth centuries in England have been considered a period of unprecedented change in farming techniques and output, of the 'Agricultural Revolution'. Current opinion sees agricultural change taking much longer, over several centuries of change and improvement. This thesis examines the contention that in Cumberland, a large county in northwest England, the period 1700 to 1850 did represent one of agricultural revolution. It is shown that isolation, a difficult physical environment, absentee landownership and peculiar tenures combined to retard improvement in both animal husbandry and field management. Although the common arable fields had largely disappeared by 1700, the huge common wastes were vital to the local agricultural economy. Encroachment on the wastes is seen as a tolerated method of increasing farm holdings; but the key change was enclosure. Examination of various physical and socioeconomic variables leads to the conclusion that altitude and slope were the dominant factors in distinguishing early from late enclosures: soil, agricultural potential, distance from urban areas and number of landowners involved do not seem to have been important. However, understanding is incomplete without considering the interplay of landlord and tenant: enfranchisement, intercommon and even personality conflicts played a part in the process. Overall, it is concluded that if there was a Cumberland agricultural revolution from 1700 to 1850 it was largely confined to the enclosure of the common wastes: that other forms of agricultural advance had to wait the later nineteenth or even the twentieth century. The thesis provides new or revised data on several matters, such as the number and size of common arable fields, and the rate of enclosure of the common wastes, and puts a wide range of agricultural changes in the eighteenth and early nineteenth centuries into context.

abstract: Doctor of Philosophy (PhD)


title: The synthesis, NMR, and conformational studies of purinophanes and approaches towards the synthesis of pyrimidinophanes

contributor:
Bell, Russell Arthur
Chemistry

subject: Chemistry Chemistry

abstract: In an effort to investigate the magnetic effects exerted by the heterobases found in ribo- and deoxyribonucleic acids, work has been directed towards the synthesis of purine and pyrimidine cyclophanes. The bridging methylene protons act as "reporter" groups of the magnetic environment of these systems furnishing values for the spatial definition of the diamagnetic susceptibility anisotropy and supplying a viable means of appraising the existing theoretical models. (8) -(N6,9)-6-Aminopurinophane (1) (an adenine based cyclophane) was the first to be prepared in our laboratory. Its nonamethylene (2) and decamethylene (3) homologs have also been synthesized using nucleophilic aromatic substitution for bridge attachment at the 6-position and the Mitsunobu reaction for alkylation at the 9-site. Both the C9 and C10 cyclophanes have been investigated using NMR spectroscopy while the structure of (9) -(N6,9)-6-Aminopurinophane has been determined using X-ray crystallography. Many of the interesting fluxional properties of the purinophane series result from restricted rotation about the N6-C6 bond and manifest themselves in the variable temperature NMR. UV spectroscopy has been used to provide further insight into the conformational properties of these molecules. The "Intact Bridge Attachment" and "Bridge Formation via Coupling" approaches to cyclophane formation have been applied towards the synthesis of the pyrimidinophane. (9) -(1,N4)-4-amino-2-one-pyrimidinophane (4) (a cytosine based cyclophane). Unfortunately, repeated attempts failed to produce the desired target molecule. The problems associated with each approach will be discussed. A semi-empirical model developed for calculation of the chemical shifts of the bridge protons in the (n) -(N6,9)-6-aminopurinophane series proved to be an effective tool for anisotropy mapping.

abstract: Doctor of Philosophy (PhD)


title: Reservoir length effects on the seismic response of concrete gravity dams

subject:
Civil Engineering
Engineering Mechanics
Civil Engineering

abstract: The behaviour of a concrete gravity dam-reservoir-foundation system is a very complex system to analyze. Currently, the length of the reservoir is assumed infinite during the seismic analysis and design of dam structures. Since many of the natural reservoir systems are finite, this assumption may significantly miscalculate the response of the dam monolith to earthquake ground motion. The objective of this research is to investigate the effect of a finite length upstream reservoir on the monolith's seismic response, including consideration of the reservoir's characteristics. This study is comprised of three main components. First, a closed form solution of the dam-reservoir problem is developed. The ground motion is assumed to only excite the dam monolith. Second, a detailed analysis procedure is used to investigate the response of the monolith when both the monolith and the reservoir's far boundary is excited. Lastly, a stress analysis is conducted to examine the effect of a finite length reservoir on the dynamic tensile stresses that are developed in the monolith. The finite length of the upstream reservoir was found to be a very important parameter in defining the response of the dam monolith to seismic input. The response of the dam-reservoir-foundation system was found to be significantly different when the reservoir's length was assumed to be finite than when it was assumed infinite. The ratio of the reservoir length to dam height (L/H), the reservoir-foundation interface, the monolith's elastic modulus, the phase of the ground motion between the monolith and the reservoir's far boundary, and the reservoir's far boundary have all been determined to be important aspects in defining the monolith's dynamic and seismic response.

abstract: Doctor of Philosophy (PhD)


title: Russell on meaning and denotation: The argument of 'On Denoting'

contributor:
Griffin, Nicholas
Philosophy

subject: Philosophy Philosophy

abstract: The aim of the thesis is twofold. Firstly, it is argued (1) that Frege's theory of meaning ('Sinn') and denotation ('Bedeutung') is the first successful non-psychologistic response to what has been called 'the puzzle of identity' and (2) that, where Frege's theory differs most significantly from the theory of meaning and denotation developed by Russell in The Principles of Mathematics and in his unpublished manuscripts on logic of 1903-1905, Russell was right. Secondly, it is shown that Russell was again right when he claimed that the central argument of 'On Denoting' completely discredits both his own and Frege's theory of meaning and denotation. An interpretation of the relevant passage of 'On Denoting' is put forward. The discussion makes evident that it is virtually impossible to disentangle that argument if one ignores his unpublished work on the topic.

abstract: Doctor of Philosophy (PhD)


title: Dividing annular/two-phase flow in horizontal T-junctions

contributor:
Shoukri, M.
Mechanical Engineering

abstract: The results of an experimental and analytical investigation of the separation phenomenon in dividing annular two-phase flow is presented. Detailed experiments have been carried out with a steam-water loop to isolate the effects of flow split, inlet quality, inlet mass flux and branch diameter on the phase and pressure distribution characteristics in horizontal T-junctions. Through the set of measurements made in the experimental program, the phase separation and pressure distribution characteristics were shown to be strongly interdependent. Based on these measurements, a physical model describing the phase separation mechanism is presented. This physical model is then developed mathematically. A model to predict the dividing flow characteristics for annular flow in a T-junction is proposed consisting of mixture and vapor phase continuity equations, two pressure change correlations and a closure relationship. The pressure change from the inlet through the run of the T is modelled by way of a balance of axial momentum at the junction based on a separated flow assumption. The branch pressure change is modelled using a balance of mechanical energy for the branching flow consisting of reversible and irreversible components. In the development of the branch model, a new equivalent inlet density for the branching flow ($\rho\sbsp{1}{*}$) and a two-phase multiplier ($\Phi\sp*$) are defined. The closure relationship links the phase separation characteristics with the junction pressure changes. It involves a balance between pressure and inertia forces within the junction volume defining a dividing surface for each phase between the run and branch flows. The degree of phase redistribution is then determined using a well defined inlet flow distribution. The model is capable of predicting the experimentally observed phase separation characteristics from three independent studies of annular/steam-water and air-water flow in dividing T-junctions.

abstract: Doctor of Philosophy (PhD)


title: Spontaneous vs directed recognition: The relativity of automaticity

contributor:
Jacoby, Larry L.
Psychology

subject: Psychology Psychology

abstract: Eight experiments are reported that examined the contrast between spontaneous and directed recognition using the flanker paradigm. The rationale was that spontaneous recognition of a flanking word would be reflected by the influence that word had on recognition of a target word. Spontaneous recognition, as indexed by flanker effects, was found but only under a restricted set of conditions. When attention was divided at test, recognition decisions for target words were faster when the flanker and target word were congruent (old flanker, old target word; new flanker, new target word) rather than incongruent (new flanker, old target word; old flanker, new target word) with regard to the decision they dictated (Exps. 1, 2, 4, 7, 8a, 8b). However, if old targets were easily identified as old, flanker effects did not emerge, even when attention was divided (Exps. 5 and 6). Surprisingly, increasing the number of prior presentations before a word served as a flanker decreased its likelihood to produce effects when old targets were words that had been presented once at study (Exps. 2 and 4). Words that had been presented to be solved as anagrams at study were effective as flankers, despite their change in physical characteristics from study to test (Exp. 7). Further, rather than the form of modality-specific transfer, flankers were more effective if they matched the modality in which old targets had been presented at study (Exps. 8a and 8b). In combination, the results show that it is the relation between the processing history of the target and flanking words, rather than the absolute history of the flanking word, that determines whether flanker effects will be observed. These findings are discussed in terms of the relativity of automaticity (cf., Neumann, 1984).

abstract: Doctor of Philosophy (PhD)


title: Structure and chemistry of retinylidene iminium salts and related systems

contributor:
Childs, R.F.
Biochemistry

subject:
Analytical Chemistry
Biochemistry
Analytical Chemistry

abstract: This thesis embodies an investigation into the structure and thermal isomerizations of retinylidene iminium salts and related systems. Over the past three decades there has been a tremendous amount of interest surrounding the structurally related natural pigments rhodopsin and bacteriohodopsin. Studies of these compounds have had a large impact in the fields of bioenergetics and visual photochemistry. Both of these proteins consist of a protonated Schiff base linkage between the retinal chromophore and the protein. A series of retinylidene iminium salts were synthesized and characterized both in solution and the solid state. A unique combination of x-ray crystallography, solid state $\sp{13}$C NMR, FTir and uv spectroscopic techniques were used in order to address the mechanism by which the protein can modify the electronic properties of the retinal chromophore in the ground state. One important conclusion of this study was that wavelength and positive charge delocalization in retinylidene iminium salts can primarily be modified by varying the distance between the anion and the proton bonded to the Schiff base nitrogen atom. It was also found that most of the positive charge in these systems is located on the nitrogen atom and the proton to which it is bonded. The thermal cis-trans isomerization about the C11-C12 bond of a series of retinylidene iminium salts was investigated by high field $\sp1$H NMR spectroscopy at ambient temperatures. It was found that the isomerizations proceeded via nucleophilic catalysis by the counterion present in the salt. No 11-cis isomer was detected at thermodynamic equilibrium for all of the salts examined. The thermal reactivity of the isoelectronic protonated poly-unsaturated aldehydes were also examined by high field $\sp1$H NMR spectroscopy. In contrast to the observed iminium salt chemistry, it was found that these species cyclized completely in superacidic media to form cyclopentene ring moieties. It was found that the rate determining step in these reactions involves additional protonation on the oxygen atom to form a dication.

abstract: Doctor of Philosophy (PhD)


title: Attawapiskat Cree land tenure and use, 1901-1989

contributor:
Preston, Richard
Anthropology

subject: Anthropology Anthropology

abstract: This thesis is an examination of Attawapiskat (James Bay) Cree land tenure and use from 1901-1989. Analysis is focussed upon continuities and changes and how these have been shaped by the State as it sought to encapsulate the Cree people. Despite the incursions of mainstream White society, it is argued that the basic integrity of Cree culture has remained intact. Indeed, land use has remained fundamentally important, and in fact, subsistence hunting is as economically and culturally important today as it was half a century ago. Similarly, while hunting for trade has been reshaped, and in some instances redefined, to meet the exigencies of changing times, there is still a reliance upon the land. In terms of land tenure, deliberate attempts at eradication of traditional Cree notions of territoriality only resulted in a temporary adoption of the externally imposed concepts, and then a subsequent abandonment of them in favour of their own workable patterns of land "ownership". Contrary to some commonly held "truths", the introduction of White "culture" and White technologies has not resulted in the destruction or erosion of Native culture. Thus, while a process of encapsulation was initiated, a simultaneous process of resistance was maintained by the Cree.

abstract: Doctor of Philosophy (PhD)


title: Psychosocial impacts in populations exposed to solid waste facilities

contributor:
Taylor, Martin S.
Geography

subject: Geography Geography

abstract: This thesis examines psychosocial impacts in three populations exposed to solid waste disposal facilities in southern Ontario. Psychosocial impacts are defined as a complex of distress, dysfunction and disability, manifested in a wide range of psychological, social and behavioural outcomes, as a consequence of actual or perceived environmental contamination. The scope of this research is based on the awareness and prevalence of exposure to environmental contaminants in Ontario, the relative absence of theory and empirical evidence to explain their determinants, and uncertainty as to ways to intervene effectively to reduce their adverse effects on human health and well-being. Three research objectives are addressed within a parallel case study design using descriptive and logistic regression analyses: (1) to determine the prevalence of psychosocial impacts among exposed individuals; (2) to investigate determinants of individual level psychosocial impacts; and, (3) to investigate the determinants of individual level actions taken in response to psychosocial impacts. Implicit across these objectives is the development of a clearer conceptual understanding of the nature and direction of the process of psychosocial impacts. The data come from an epidemiological survey of residents (N = 696) living within a prescribed radius from each of three solid waste facilities. The analytical model which guided the analysis was informed by a socioecological model of health and well-being and has three components: external variables (e.g., individual and exposure related variables), mediating variables (e.g., social network membership and involvement, health status measures as well as measures of general psychosocial health and well-being), and outcome variables (e.g., concern, effects and actions). Results show that levels of outcome reported vary by site. This finding indicates that the process of psychosocial impacts cannot be divorced from the community context within which they occur. Further, results for a series of site specific analyses show that outcome measures can be successfully explained by a combination of external and mediating factors. However, given the number and diversity of variable types emerging, there is no single cause and effect relationship operating. The implication is that strategies aimed to address and alleviate psychosocial impacts need to be specific to the characteristics of the populations in particular settings. Contributions made by the thesis are theoretical, development of a socioecological conceptual framework within the context of environmental stress theory; methodologic, development of an epidemiologic survey designed to measure psychosocial impacts; and substantive, analysis of the prevalence and determinants of psychosocial impacts

abstract: Doctor of Philosophy (PhD)


title: Nuclear structure of iridium-190,192,194

contributor:
Burke, D.G.
Physics

subject: Physics Physics

abstract: The nuclear structures of ¹⁹⁰,¹⁰²,¹⁹⁴Ir were investigated with single-nucleon transfer reactions. The (d,t) reactions into ¹⁹⁰,¹⁰²,¹⁹⁴Ir used 18 MeV deuterons beams, and the (d,p) reactions into ¹⁹²,¹⁹⁴Ir utilized beams of 16 MeV deuterons. Single-proton transfer experiments were also performed on targets of ¹⁸⁹Os. The (α,t) reaction employed beams of 30 MeV α-particles, and the (³He,d) reactions used a 28 MeV ³He beam. The reaction products were analyzed with a magnetic spectrograph, and detected with photographic plates. The energy resolutions (FWHM) of the detected particles were typically ≃5.7 keV for (d,t), ≃8.9 keV for (d,p), ≃10 keV for (α,t), and ≃15 keV for (³He,d) reactions. For the single-neutron transfer reactions, spectra were recorded at a large number of angles (≥15). The angular distributions of cross sections were fitted with theoretical distributions from DWBA calculations, and the spectroscopic factors were obtained. For the (d,t) reactions, the fits to the angular distributions were performed in many cases with 2 l-values. By comparing the ratios of (α,t) and (³He,d) cross sections, the dominant transferred l-value was determined. Level energies, parities, spectroscopic strengths, and possible spin values were determined up to approximately 1 MeV excitation energy in ¹⁹⁰,¹⁹²Ir and 700 keV in ¹⁹⁴Ir. In order to obtain more information regarding the spins of levels in ¹⁹²Ir, multi-dimensional scaling programs were applied to known γ-ray intensities. The method appeared to be successful, and spins were suggested for many low-lying levels. The experimental results were compared with the IBFFM for ¹⁹²,¹⁹⁴Ir, ESUSY for ¹⁹²Ir, and the Nilsson model for ¹⁹⁰,¹⁹²Ir. The formalism for dealing with mixed configurations in the target ground state was developed, and significant effects were found for the single-proton transfer cross sections since the ¹⁸⁹Os target had significant admixed amplitudes. It was found that the models can only approximate the structure of odd-odd Ir nuclei.

abstract: Doctor of Philosophy (PhD)


title: Characterization of phosphorylation sites on the E1A polypeptides of human adenovirus type 5

contributor:
Branton, Philip E.
Medical Sciences

subject:
Medical Sciences
Medical Sciences

abstract: Human adenoviruses can induce tumors in rodents through the action of the products of two viral genes, termed E1A and E1B. E1A produces multiple transcripts as a result of differential splicing, however, only the products of the 13S and 12S mRNAs appear to play a role in oncogenicity and cell transformation. These mRNAs encode proteins of 289 and 243 residues that are identical except for the presence of a unique 46-amino internal sequence. Each of these species migrates in polyacrylamide gels as at least two electrophoretically separable forms which differ in apparent molecular mass by about 4 kDa. Previous studies had indicated that differential phosphorylation is largely responsible for this shift in gel migration. The objective of this thesis was to identify the phosphorylation events responsible for this mobility shift, and to determine the functional significance. These studies focussed on phosphorylation sites towards the amino terminus of E1A proteins. Mutants were generated by site-directed mutagenesis in which known phosphorylation sites at Ser89 and Ser96 were altered to alanine residues. Characterization of these and other mutants suggested that phosphorylation at Ser89 was largely responsible for the shift in gel migration of the E1A proteins, and may regulate phosphorylation at Ser96. Removal of the phosphorylation site at Ser89 was found to have no significant effect on the ability of E1A proteins either to transactivate E3 expression or to repress SV-40 enhancer activity, but it did reproducibly reduce E1A-mediated transforming activity by about three fold. These results suggested that phosphorylation at Ser89 may be of some regulatory significance. Ser89 as well as Ser219 were shown to be phosphorylated in vitro by the cell cycle protein p34^(cdc2Hs) which had been purified by immunoprecipitation using specific antiserum. In addition, E1A proteins were found to be most highly phosphorylated during mitosis, the period in the cell cycle of maximal p34^(cdc2Hs) activity. These results suggested that p34^(cdc2Hs) or a related protein kinase phosphorylates E1A proteins at these two sites in vivo.

abstract: Doctor of Philosophy (PhD)


title: Determination of the structural features of A-band lipopolysaccharide from a rough mutant of Pseudomonas aeruginosa

contributor:
MacLean, D.B.
Chemistry

subject: Chemistry Chemistry

abstract: "A-band" lipopolysaccharide (LPS) is believed to be widely distributed among serotypes of the bacterium Pseudomonas aeruginosa. The present work is a study of the structural features of the polysaccharide portion of A-band LPS ("A-PS") from strain AK1401. The A-PS was found to consist principally of D-rhamnose, with lesser amounts of 3-O-methylrhamnose, ribose, mannose, and glucose. These monosaccharides were found to exist as 1,3-linked rhamnopyranose, 1,2-linked rhamnopyranose (2:1 ratio), 1,4-linked 3-O-methylrhamnopyranose, and 1,4-linked manno- and gluco-pyranoses; the ring form and linkage positions of ribose could not be determined directly, but could be inferred to be 1,3-linked ribopyranose. ¹H- and ¹³C-NMR of the intact A-PS showed the presence of three principal monosaccharides, all of which were α-D-rhamnosides, suggesting a trisaccharide repeating unit structure composed of two α-(1,3)-linked rhamnopyranosides and one α-(1,2)-linked rhamnopyranoside. The ¹H-NMR spectrum of this repeating unit was assigned by use of hononuclear correlation spectroscopy (COSY) and relayed coherence transfer (RELAY) experiments. Nuclear Overhauser enhancement experiments allowed the assignment of the sequence of monosaccharides. The deduced structure of the repeating unit of AK1401 A-PS is: (→2)-α-D-Rhap-(1→3)-α-D-Rhap-(1→3)-α-D-Rhap-(1→)m. This work represents the first assignment of the ¹H-NMR spectrum of this repeating unit structure. The A-PS was subjected to sodium periodate oxidation, reduction, and mild acid hydrolysis (Smith degradation), which yielded an oligosaccharide of predictable structure as the major product. The peracetate derivatives of the minor oligosaccharide products were studied in an attempt to learn more about the role of the monosaccharides that are not included in the repeating unit. Gas chromatography-mass spectrometry (GC-MS) revealed the presence of at least five oligosaccharides in addition to the major product. The structures of two of these could be inferred from the mass spectra as: [equation omitted] A fraction containing oligosaccharides which were too involatile to be analyzed by GC-MS was isolated by liquid chromatography and analyzed by direct chemical ionization (DCI) mass spectrometry. This revealed the presence of at least two components, one of which was inferred to be the peracetate of: (3-O-MeRha)₄-(3-O-MeHex)₂-Gly-ol. These components provide some insight into the structure of the non-repeating portion of the A-PS.

abstract: Doctor of Philosophy (PhD)


title: Thermodynamic studies in liquid Fe-Nb-O, Fe-AI-O, Fe-Al-Mn-O systems, using solid electrolytes

contributor:
Kay, D.A.R.
Metallurgy

subject: Metallurgy Metallurgy

abstract:
A high temperature electrochemical technique has been developed, to continuously monitor the oxygen activity in iron based melts.

The electrochemical cell used, can be represented as:

Mo | Cr(s) -Cr₂O₃(s) | Calcia stabilised zirconia | Fe-M-O(ℓ) |Mo-ZrO₂, Mo cermet

The electrolyte was in the form of a crucible to hold the metallic melt.

The standard free energy change for the reactions:

FeNb₂O₆(s) ⇆ 2NbO₂(s) + Fe(ℓ) + 2O lw/o

FeNb₂O₄(s) ⇆ Al₂O₃(s) + Fe(ℓ) + O lw/o

and the influence of manganese content of the melt on the oxygen activity for the equilibrium:

(Fe1-x, Mnx)O.Al₂O₃(s) ⇆ Al₂O₃(s) + (1-x)Fe(ℓ) + xMn lw/o + O lw/o

were determined using the technique at a temperature range of 1550 - 1600ºC.

The results can be summarized as:

(a) ΔGºT[FeNb₂O₆(s) - NbO₂(s)] = 105870 - 42.64ºT (±600) cal/mole FeNb₂O₆ [1550ºC - 1600ºC]

(b) ΔGºT[FeAl₂O₄(s) - Al₂O₃(s)] = 49910 - 21.50 T(±300) cal/mole FeAl₂O₄ [1550ºC - 1600ºC]

(c) Increasing the manganese content in the melt decreases the value of logh₀ in equilibrium with the transition reaction.

The nature of the deoxidation inclusions of the liquid systems Fe-Nb-O, Fe-Al-O and Fe-Al-Mn-O were studied by X-ray analysis and their morphology by scanning electron microscopy. In the Fe-Nb-O system the inclusions were identified as NbO₂ and FeNb₂O₆ and appeared to form agglomerates of small crystallites.

In the Fe-Al-O and Fe-Al-Mn-O the inclusions were identified as Al₂O₃ clusters along with FeAl₂O₄ or (Fe,Mn) Al₂O₄ respectively. The thermodynamic data obtained by the present technique are believed to be of high accuracy and the method significantly contributes in the studies of complex deoxidation systems at steelmaking temperatures.

An attempt was made to use the present electro-chemical technique in studying the liquid Fe-Ti-O system at high oxygen potentials. Further research is suggested to fully resolve the results.

abstract: Doctor of Philosophy (PhD)


title: Targeting of Candida tropicalis trifunctional enzyme to peroxisomes in yeast: Identification of a carboxy-terminal tripeptide peroxisomal targeting signal

contributor:
Rachubinski, Richard A.
Biochemistry

subject: Biochemistry, Biophysics, and Structural Biology

abstract: The nature of the peroxisomal targeting signal in Candida tropicalis trifunctional enzyme, hydratase-dehydrogenase-epimerase (HDE) was investigated. The first part of this thesis describes the cloning and sequencing of the cDNA and gene encoding HDE. The second and third parts of the thesis describe the amino acid sequence (and general nature) of the signal that directs HDE to peroxisomes in yeast. The cDNA and gene encoding C. tropicalis HDE was isolated from a λgt11 cDNA expression library and from a λEMBL3 genomic library, respectively. Primary sequence analysis of both the cDNA and the gene revealed a single open reading frame of 2718 nucleotides encoding a protein of 906 amino acids (calculated molecular mass = 99,481 Da). The gene encoding HDE was expressed in the yeasts Candida albicans and Saccharomyces cerevisiae. The cellular location of HDE was determined by subcellular fractionation followed by western blot analysis of peroxisomal and cytosolic fractions using antiserum specific for HDE. HDE was found to be exclusively targeted to and imported into peroxisomes in both heterologous expression systems. Deletion and mutational analyses were used to determine the regions within HDE which are essential for its targeting to peroxisomes. Deletion of a carboxy-terminal tripeptide Ala-Lys-Ile completely abolished targeting of HDE to peroxisomes, whereas large internal deletions of HDE (amino acids 38-353 or 395-731) had no effect on HDE targeting to peroxisomes in either yeast. Substitutions within the carboxy-terminal tripeptide (Ala → Gly and Lys → Gln) supported targeting of HDE to peroxisomes of C. albicans but not of S. cerevisiae. Antiserum directed against the carboxy-terminal 11 amino acids of HDE, containing the Ala-Lys-Ile tripeptide (anti-AKI) was used to probe subcellular fractions from several yeasts and rat liver. The anti-AKI serum reacted exclusively with multiple peroxisomal proteins from the yeasts C. tropicalis, C. albicans and Yarrowia lipolytica suggesting a common motif for the targeting of some proteins to yeast peroxisomes, the prototype of which is the HDE carboxy-terminal tripeptide Ala-Lys-Ile.

abstract: Doctor of Philosophy (PhD)


title: Deep bioturbation by Axius serratus in the Strait of Canso, Nova Scotia

contributor:
Risk, Michael J.
Geology

subject: Geology Geology

abstract:
The thalassinid crustaecan Axius serratus, was investigated in order to better understand its ecology and effect on the sediment, in the Strait of Canso, Nova Scotia. The shrimp, previously virtually unknown from Canadian waters, was found to be a common element of the benthic biota south of the Canso causeway. Axius exploits vast areas of sediment, and establishes semi-permanent burrows. Densities in the study area average from 9 to 15 per square meter and uniform spatial distributions were noted.

Areas subject to heavy industrial pollution, termed barren zones, contain no forams, ostracods or molluscs. Axius serratus is the only invertebrate observed living in the barren zones, and may well serve as an indicator of water quality.

Polyester resin casts show that the burrows are open to a depth of at least 2.9 m. - the deepest bioturbation event recorded: Burrows are lined with grass, and exhibit a knobby exterior similar to that of Ophiomorpha nodosa.

Variations and trends in the mass physical properties of the sediment of the Strait of Canso are related to the distribution of Axius burrows. Sediment adjacent to burrows shows relatively higher values for grain density and mass unit weight. Effect is at maximum near burrow opening.

abstract: Master of Science (MS)


title: Oxocomplexes of Rhenium

contributor:
Lock, C.J.L.
Chemistry

subject: Chemistry Chemistry

abstract:
In the higher oxidation states (V, VI and VII) the outstanding feature of the chemistry of rhenium is the tendency to form compounds containing rhenium-oxygen multiple bonds. This thesis examines the nature of these Re-O multiple bonds, and in particular, derives a correlation between the bond length and the Re-O stretching force constant. The validity of this empirical correlation is tested over a limited range of compounds. The crystal structure of KReO₄ was redetermined to a high precision to test the predictions of this correlation. A normal coordinate analysis of the ReO₂ (CN)₄³ ion was performed, including data from ¹³C suhbtituted and ¹⁸O enriched complex ions. Some new infrared data for complexes of type ReO(OR)L₄ are reported (R = hydrogen atom or alkyl group), and the rhenium-oxygen stretching frequencies are assigned. Force constants are calculated for complexes of type Re₂O₃L₈ and ReO(OR)L₄.

The crystal structures of [ReO₂en₂]Cl and [ReO₂py₄]Cl.2H₂O were redetermined, to provide some accurate data on Re-O double bonds. The structure of the compound [ReO(OH)en₂][CIO₄]₂ was also redetermined and an accurate bond length for the Re-O(H) bond was finally obtained. The structure of the compound Re₂O₃py₄Cl₄ was determined, and was found to be different from that predicted in the literature. The nature of the intramolecular interactions in this compound were examined in an effort to explain the unusual stereochemistry, and the asymmetry of the compound. Pyridine groups were found to play a dominant role in the structure of the compound. The structure of ReO(OEt)py₂Cl₂ was also determined, giving a value for the Re-O(Et) bond length. Pyridine groups were again the dominant factor in the stereochemistry of the complex. The rhenium-oxygen bonding in complexes of type ReO(OR)L₄ was found to be similar to that found in Re₂O₃L₈ type complexes.

abstract: Doctor of Philosophy (PhD)


title: Magnetic field resistivity of superconducting bismuth oxides

contributor:
Datars, W.R.
Physics

subject: Physics Physics

abstract: The superconducting transition in the magnetic resistance of members of the family of bismuth based high temperature superconductors was investigated. Measurements were performed in magnetic fields up to 1.7 T. Small current densities ranging from 0.03 A/cm² to 3.0 A/cm² were applied. The resistivity of Bi₂Sr₂CaCu₂Ox single crystals was analyzed in terms of the thermally activated flux flow expression, ρ =ρ₀U/T exp(-U/T) where T is the temperature. It was found that the activation energy was given by Uα(Hsinθ)^(⁻α) where α≈1/3 and that the prefactor had the form, ρ₀Hsinθ, where H was the applied field and θ the angle of the field with respect to the CuO₂ planes. Results demonstrated that dissipation could be accounted for by the motion of two-dimensional vortices whose density is given by the field, Hsinθ, projected on the CuO₂ planes. Measurements of the resistivity and current dependent resistivity were performed with two Sn-doped and two Sb-doped polycrystalline Bi(1.7)Pb(0.3)Sr₂Ca₂Cu₃O(y) samples. Features in the temperature derivative of the resistivity curves were associated with the presence of a superconducting transition between superconducting grains, coupled by weak links with a distribution of critical currents and critical temperatures, and the superconducting transition within grains. The transition between grains was more strongly suppressed in temperature with the application of a magnetic field in samples with weaker coupling between grains. The presence of a transition in a magnetic field due to weak links between grains was verified at 77 K by the observation of a current dependent resistivity in a magnetic field. Measurements of a Bi₂Sr₂CaCu₂Ox diffusion grown thick film ring were done. The transverse voltage, the voltage at the centre of a 120 μm thick branch with respect to the centre of a 76 μm thick branch, was measured. A higher critical temperature from the presence of more texturing in the 76 μm branch as determined by separate resistivity, x-ray and scanning electron microscopy measurements was consistent with the measurement of a crossover from a negative to positive transverse voltage as the temperature of the sample went through its superconducting transition.

abstract: Doctor of Philosophy (PhD)


title: Physics-based microwave device modeling and circuit optimization

contributor:
Bandler, John W.
Electrical and Computer Engineering

abstract: This thesis addresses physics-based microwave device modeling and circuit optimization, including conventional and statistical device modeling, performance-driven and yield-driven circuit design. Approaches for physics-based device modeling are reviewed. Fundamental techniques of physics-based analytical MESFET modeling are presented. Device performance and parameter extraction with physics-based models (PBMs) are discussed. Nonlinear circuit analysis with PBMs integrated into the harmonic balance (HB) method is presented. A detailed formulation of the HB equations with MESFET PBMs is given. An efficient Newton method for solving the HB equations is discussed. Gradient-based optimization for circuit design is addressed. Physics-based circuit optimization integrates efficient adjoint sensitivity analysis approaches, the HB simulation method and PBMs. The physical (geometrical, material and process-related) parameters can be directly treated as design variables. Simultaneous device-circuit design is facilitated. The features of physics-based circuit optimization are demonstrated by two circuit design examples. Statistical modeling at different levels is discussed. Statistical parameter extraction and postprocessing are used to obtain statistical models to predict parameter statistics. The resulting statistical device models are verified by comparing the statistics of measurements with the corresponding statistics obtained by Monte Carlo simulation. Statistical modeling with equivalent circuit models (ECMs) and PBMs is demonstrated. Yield-driven circuit design is addressed based on a one-sided ℓ₁ optimization algorithm with a generalized ℓｐ function. Yield optimization of MMICs with PBMs for passive and active devices is discussed. Its features are demonstrated by a three stage X-band MMIC amplifier design. A comprehensive approach to predictable yield-driven circuit design exploiting a novel statistical model is presented. For the first time, the yield estimated by Monte Carlo simulation is shown to be consistent with the yield predicted directly from device measurement data. Simultaneous device-circuit yield optimization assisted by yield sensitivity analysis is also demonstrated.

abstract: Doctor of Philosophy (PhD)


title: Modelling of Ar-CO₂ thermal plasma

contributor:
Chang, J.S.
Engineering Physics

subject:
Engineering Physics
Nuclear Engineering
Nuclear Engineering

abstract: A chemical kinetic model has been constructed to predict the pressure and gas and electron temperature dependency of the neutral and ionic species composition in Ar-CO₂ mixtures under thermal plasma conditions. Pure Ar and Ar-C models have also been constructed as a part of this investigation. The models include electron impact, thermal impact, ion-molecule, and recombination reactions as well as accounting for diffusion. Important metastable and excited states of species have been accounted for as well as the presence of neutral molecules, radicals, and atoms, positive and negatively charged atoms and molecular ions as well as electrons. All relevant electron temperature, gas temperature and pressure terms have been included, and primarily experimentally derived reaction rate constants were utilized. Electron and gas temperature dependent species concentrations were obtained under both thermodynamic equilibrium and non-equilibrium conditions for gas temperatures from 300 to 15000 K, electron temperatures from 300 to 20000 K, and pressures from 1 Torr to 15200 Torr. Percentage mixtures of C and CO₂ in Ar were varied between 0.1 and 40%. Results indicate that the neutral and excited species Ar, Ar*, Ar**, C, CO, CO₂, O, O₂ and O₃, positive ions Ar⁺, Ar₂⁺, C⁺, CArO⁺, CO⁺, CO₂⁺, CO₄⁺, C₂O₂⁺, O⁺, O₂⁺, O₄⁺, and O₅⁺ and negative ions CO₃⁻, CO₄⁻, O⁻, O₂⁻, and O₃⁻ and electrons are observed. Under thermodynamic equilibrium conditions, Ar, C, CO, CO₂, and O were found to be the dominant neutral species, C⁺, CO₄⁺, O⁺, and O₂⁺ the dominant positive ions, and O⁻ and electrons the dominant negatively charged species under certain gas temperature ranges. The introduction of thermodynamic non-equilibrium conditions, changes in gas pressure, and percentage mixture of C or CO₂ were observed to have a significant influence on the temperature dependent concentrations of these species. The results were found to be in good agreement with previous experimental and theoretical results. Comparison of the present results with the results of the Saha equation seem to indicate that the simple Saha equation type approach may mispredict the plasma density of Ar, Ar-C, and Ar-CO₂ mixtures under thermal plasma conditions.

abstract: Doctor of Philosophy (PhD)


title: Analyses of optimal policies for dynamic inventory and maintenance systems

contributor:
Parlar, Mahmut
Management Science/Information Systems

subject:
Management Science/ Systems
Management Information Systems
Management Information Systems

abstract: This thesis represents research in the combined areas of inventory and maintenance. It analyzes two independent inventory and maintenance problems under dynamic systems: (i) a production and maintenance problem and (ii) a repairable-item inventory problem. For each problem, the thesis develops a new control model and proposes a simultaneous determination of optimal inventory and maintenance policies. The first part of the thesis examines a production process where the process performance deteriorates over time in the absence of preventive maintenance. First, it develops a new finite-time control model for optimal production and maintenance decisions by combining a dynamic maintenance model with a production control model. Second, it derives the necessary conditions for optimal production and maintenance controls using the maximum principle. Finally, it proposes two optimization algorithms for numerically solving the necessary conditions already derived. The second part of the thesis considers the repairable-item inventory problem, which may be faced at each period by the inventory manager responsible for determining the optimum quantities to purchase new serviceable units, to repair and to junk returned repairable units in order to satisfy random demand for serviceable units. First, it proposes an inventory model for repairables, incorporating several important features. The model includes a periodic review policy, random demand, lost sales for unsatisfied demand, set-up costs for ordering and repair, and a dynamic return process. Second, it employs a quite different solution methodology from what the previous research has used. The approach employed here is a 'Markov decision process (MDP)'. With this approach, the inventory problem is remodelled as a discrete-time Markov decision problem with two-dimensional state and three-dimensional decision spaces and then solved for finite-time planning horizon using the backward induction algorithm and for infinite-time planning horizon using the method of successive approximations. Finally, it introduces and utilizes two acceleration techniques, the error bounds approach and State Decomposition by Dimension (SDD), for speeding up the convergence of the computational methods described above.

abstract: Doctor of Philosophy (PhD)


title: Radical cyclization to the imino functional group

contributor:
Warkentin, John
Chemistry

subject: Chemistry Chemistry

abstract: Aryl radicals, generated by abstraction of Br from ortho-substituted bromoarenes, add to an imino functional group (C = N) in the ortho substituent in a competition involving 6-endo closure to the C and 5-exo closure to the N-atom. Absolute rate constants for the 6-endo closure were measured for two systems; k_(6-endo)>10⁸ s⁻¹ (80℃). Rate constants for the competing 5-exo closure were estimated to be 10-100 fold smaller. The utility of the 6-endo closure for the synthesis of tetrahydroisoquinolines was demonstrated with eight aldimine systems. Moreover, 1,2-asymmetric induction with up to 57% of diastereomeric excess was discovered for the 6-endo closure to the C-atom of the CN double bond derived from glyceraldehyde acetonide. Radical cyclization in the lower homologue, wherein the choice was between 4-exo closure to the N-atom and 5-endo closure to the C-atom, was not competitive with either 1,5 H-atom transfer of the azomethine proton (aldimine) or transfer of H-atom from Bu₃SnH (ketimine). In the isomeric imines, wherein the choice was between 5-exo closure to the C-atom and 6-endo to the N-atom, aryl radical closure was shown to be exclusively in the 5-exo sense. The absolute rate constant for the 5-exo closure to the C-atom was measured to be 5.3x10⁸ s⁻¹ (80℃). Finally, bis(tributylstannyl)benzopinacolate (TBBP) was found to be a novel source of canned tributylstannyl radicals.

abstract: Doctor of Philosophy (PhD)


title: A cue-compounding model of semantic priming

contributor:
Brooks, L. R.
Psychology

subject: Psychology Psychology

abstract: Three projects on semantic priming are reported that converge on a variant of Ratcliff & McKoon's (1988) cue-compounding model. In Chapter 2, two experiments test the semantic matching mechanism of backward priming and nonword facilitation. Contrary to predictions derived from the semantic match, results from Experiment 1, in which stimulus onset asynchrony (SOA) is manipulated, indicate that backward priming and nonword facilitation are caused by independent mechanisms. Results from Experiment 2, which manipulates relatedness proportion and nonword ratio by including different proportions of "related" nonwords in the list, concur with the separate mechanism hypothesis. The cue-compounding model is presented in Chapter 3 to account for the data. In Chapter 4, two further experiments investigate semantic priming of degraded targets. Spreading activation accounts (e.g., Collins & Loftus, 1975) predict that priming should be greater if degradation slows identification of the target. However, it was found at at short SOA, degrading the target either by presenting it in mixed upper and lower case letters (e.g., DoCTor) or by masking it after a brief presentation (150 ms) decreased priming against a neutral baseline. It is asserted that this pattern of results is inconsistent with spreading activation accounts, but can be simulated with the model presented in Chapter 3. In Chapter 5, a critique of a recent article by McNamara (in press a) is presented. McNamara reported three experiments demonstrating three-step mediated priming (Experiment 1) and intertrial prime-target lag (Experiment 2 and 3). Although the results lead McNamara to conclude that spreading activation is the better account, this critique asserts that his results do very little to distinguish between current models because of questionable inferences and statistical procedures. The model in Chapter 3 is used to simulate three-step mediated priming.

abstract: Doctor of Philosophy (PhD)


title: A study of the implications of soil-structure interaction effects on the seismic response of high-rise reinforced concrete buildings

contributor: Civil Engineering and Engineering Mechanics

abstract: In spite of significant improvements in the quantification of site effects in the NBCC (National Building Code of Canada) since the introduction of the foundation factor (F) in 1965, recent parametric studies have shown the 1990 NBCC provisions for site effects to be inadequate. In addition, soil-structure interaction effects are neglected in the current NBCC provisions. The current study, aimed at investigating the implications of these soil-structure interaction effects on the seismic response of high-rise reinforced concrete buildings, is carried out for three cities in Canada, namely Ottawa, Vancouver and Prince Rupert. Soil models are developed to correspond to the soil classifications used to define F in the 1990 NBCC. For each of the three cities, structural models are developed to represent both 20-storey reinforced concrete ductile moment-resisting frames and ductile flexural walls. Three sets of ground motion records are developed to represent the postulated bedrock motions at each of the three cities, based on the magnitude and source-distance combinations dominating the seismic hazard at the respective sites. The computer program FLUSH is used to perform the analyses of the various soil-structure systems. Results from the current study indicate that the code F values generally underestimate the site effects associated with the respective soil deposits, but appear to be reasonably adequate, in most cases, when soil-structure interaction effects are taken into consideration. In spite of some apparent deficiencies in the code F values, the 1990 NBCC design base shear is shown to be conservative for regular high-rise reinforced concrete buildings. Conventional uncoupled analyses are shown to provide estimates of the coupled base shear demand that are too conservative. A simple measure to account for the inertial interaction effects in uncoupled analyses is proven to provide a significant improvement in the prediction of the coupled base shear demand. A simplified approach to estimate the coupled system period is shown to provide a satisfactory estimate of values based on the rigorous, but time-consuming coupled analyses.

abstract: Doctor of Philosophy (PhD)