title: Dynamic Behaviour of Head Loss in a Deep Bed Granular Filter Based on Deposition Morphology

contributor: Civil Engineering and Engineering Mechanics

subject:
Civil Engineering
Engineering Mechanics
Civil Engineering

abstract: A review of the literature related to assessing treatment efficiency and head loss build-up using particle count and size distribution indicates some deficiencies and limitations. These deficiencies and limitations indicate several shortcomings in the available head loss models. It was noted that previous research work, which used particle size analyzers, have experienced difficulty and uncertainty in obtaining the true particle count. A procedure to correct the particle count, supported by quantitative and qualitative validation, is provided. Result obtained from past investigations on floc geometry, and its mode of deposition, have also displayed a pronounced disparity. Furthermore, no photographic evidence has been published that shows the particle dendrites in liquid. Most observations of deposition patterns relate to conditions that exhibit a substantially different behaviour from conventional filter media characteristics. The objective of this work was to develop a mathematical model which describes the head loss in deep bed granular filter based on different modes of deposition. The deposition models include parameters that account for the dynamic fraction of particles that contribute to additional surface area and the change in geometry. The dynamic fraction of particles that contribute to smooth coating and dendrite deposition in filter containing deposit are also included in the model. The deposition morphology was validated visually using an optical fibre endoscope and quantitatively using the filtration test. Three mathematical models have been developed for describing the effect of different deposit morphologies on the head loss build-up in sand filters. The models predict the head loss for a specific deposition mode and a combination of (different) modes. The first model is based on the assumption that retained particles form a relatively smooth coating around the filter grains (smooth coating model). The second model is based on the assumption that retained particles can act as additional collectors, forming chain-like depositions (dendrites mode model) as proposed by O'Melia and Ali (1978). A refinement to the O'Melia model is also proposed. In particular, the variation in porosity and the factor which represents the fraction of retained particles that contribute to the additional surface area were considered in the model refinement. The effect of change on the geometry of the filter grains were considered as well. In the third model, adsorption and bridging were proposed as combined mechanisms of polyelectrolyte action during filtration of small silica (5 um) suspension. Therefore, this model is based on the assumption that the deposition takes place in two stages: smooth coating and dendrite deposition (combined mode model). It is also hypothesized that more than one mode of deposition may govern the deposition process during the filter time. Results from the experimental program and analytical modelling were used to validate the proposed deposition morphologies and to map-out the important factors responsible for different geometries and their contribution to head loss build-up. Reasonable agreement was observed between the measured and predicted head loss. The proposed models are general in nature and may be extended to conditions other than those used for validation, provided that the deposit morphology is the same. The accuracy of the proposed combination of different deposit morphologies was confirmed using experimental data. An analysis and possible explanation for the similarity and dissimilarity of the optimum coagulant dosage between the results from a jar test and filtration test are presented.

abstract: Doctor of Philosophy (PhD)


title: The Song of Moses (Deut. 32:1-43)

contributor:
Baumgarten, A.
Meyer, B.F.
Religion

subject: Religion Religion

abstract:
The Song of Moses (Deut. 32:1-43) has been variously dated in the critical literature of the past 160 years. Scholars have proposed dates ranging from pre-monarchial Israel to the post-Exilic community. The effort of the present thesis is to present a critical review of the arguments on dating and, more important, to make a positive, concrete proposal for dating and, more important, to make a positive, concrete proposal for dating the Song. This proposal is based, first, on a new philological analysis; second, on the converging evidence of other analyses (genre, structure, style, and historical allusions). The conclusion is that the date of the Song's original composition is the late ninth century, B.C.

The sequence of treatment is as follows: a review of the history of research on dating; presentation of text and translation with supporting notes; philological analysis (including consideration of some stylistic as well as linguistic traits); analysis of rhetorical and strophic structure and so, finally, of the sense of the Song, in particular of those elements of the sense which are indicative of the date of composition.

abstract: Doctor of Philosophy (PhD)


title: Māyā in Śankara with Reference to Śankara's Bhāsya on the Brahma Sūtra--from a Phenomenological Viewpoint

contributor:
Arapura, J. G.
Religion

subject: Religion Religion

abstract: The conception "māyā" has been translated as "illusion" by many who interpret the Advaita Vedānta of Śankara. What we intend to accomplish in this dissertation is to determine if this translation is the correct one. This will be accomplished in two parts. The first will entail an historical survey of māyā in the early tradition and samvrti in Mādhyamika Buddhism and pre-Śankara Advaita. Then we will review Śankara and the post-Śankara Advaita on māyā. Part Two is a phenomenological inquiry into māyā, in the Brahma Śutra bhāsya of Śankara. Here we will be concerned with the structures of the name-form complex, language, and analogue, and their relation to māyā. We will also point out other possible interpretations of the concept "māyā" in Śankara's thought.

abstract: Doctor of Philosophy (PhD)


title: Tho Religious Thought of Rammohun Roy

contributor:
Younger, Paul
Religious Sciences

subject: Religion Religion

abstract:
This in a study of a Rammohun Roy's participation in the development of Hindu religious thought. It is an attempt to understand Hindu religious thought through the writings of Rammohun Roy by examining why so much of what he said, wrote, and did was contentious.

It has been customary, in studies of Rammohun Roy's religious thought, to concentrate on his opposition to the use of images in worship. This emphasis has made it appear that Rammohun Roy's most substantial contribution to the development of Hindu religious thought has been to draw attention to polytheism and image worship, and to make it clear that these do not represent the best expressions of Hindu theology and worship.

That issue forms part of this study, but this study is considerably broader. It discusses Rammohun Roy's theological position both in terms of the polytheism which he opposed and the monotheism which he supported. But it includes more than his theological position. It analyzes the authority upon which he based his theology. That discussion has two dimensions: firstly there is Rammohun Roy's criticism of what he perceived to be the accepted basis of authority, and secondly there his suggestion for a more adequate basis of authority. This study also analyzes the debates which Rammohun Roy had with some of his contemporaries about the qualifications which were expected of those involved in theological discussion.

This study indicates that Rammohun Roy's religious thought was contentious in many areas, and that the theological issues were not necessarily the most contentious. In fact, it is misleading to study the debates between Rammohun Roy and his contemporaries in purely theological terms, since that fails to account for the vehemence of some of the opposition which he encountered. The most contentious issues between Rammohun Roy and some of his contemporaries were not definitions of God, but questions about people's capacity to benefit from theological discussions and questions about the qualifications expected of those who engaged in such discussions.

The study suggests that in this situation theological debate was contentious as much because of the context in which it occurred as because of the actual theological positions enunciated in the debate. It suggests that the distinctions between the insider and outsider, initiate and uninitiate, and qualified and unqualified are distinctions of great importance in religious discussion, and that if the implicit boundaries these categories are disregarded, serious disagreement will result. The study concludes that Rammohun Roy challenged the traditional boundaries between these categories, and that this challenge was the most important reason for the opposition to him.

abstract: Doctor of Philosophy (PhD)


title: The Meaning and Significance of this Concept of Righteousness in the Gospel of Matthew: With Special Reference to the Use of this Concept in the Dead Sea Scrolls and the Tannaitic Literature

contributor:
Sanders, E.P.
Religion

subject: Religion Religion

abstract:
It is the aim of this study to define the meaning and delineate the significance of the concept of righteousness in the Gospel of Matthew. In order to achieve this aim, it was necessary to incorporate an analysis of the concept of righteousness in the Dead Sea Scrolls and the Tannaitic literature. It is only against this background that the full significance of the Matthean concept to the opinion of righteousness is revealed.

Contrary to the opinion of numerous scholars, this study concludes, that in the Gospel of Matthew, righteousness does not refer to the gift of God for man but rather to the demand of God upon man. Righteousness refers to right conduct, namely conduct based on an extremely meticulous interpretation of the law; an interpretation based on a hermeneutical principle reminiscent of the Rabbinic practice of making a fence around Torah.

This conclusion does not imply that Matthew advocates that salvation is attainable by man's own effort. In the Gospel of Matthew the concept of righteousness does not have a soteriological function as it does in the Pauline writings. To compare the Matthaean and Pauline concepts of righteousness is not equivalent to comparing their respective teachings on the nature of salvation. Matthew and Paul agree that salvation is the gift of God. But in contrast to Paul, who expresses this idea in terms of the concept of righteousness, Matthew expresses it without reference to this concept. Consequently, the theological reason underlying the numerous attempts to bring the meaning of the Matthaean righteousness-terminology into agreement with that of Paul has been obviated by this study.

With respect to the problem of significance, this study clearly shows that the concept of righteousness does not play a role in Matthew's self-understanding as a follower of Jesus. According to Matthew, those who are properly religious in a Christian sense are known disciples, not as the righteous. The essence of discipleship is not expressed as doing righteousness (a term referring to the demand of God upon man) but as doing the will of God (a term stressing both the gift and demand).

Why in fact does Matthew employ the concept of righteousness in his gospel? This study concludes that the concept of righteousness has a provisional function in the Gospel of Matthew. It provides a point of contact between the religious understanding of first-century Palestinian Jews and the teaching of Jesus as Matthew understood it.

It is the nature of such a provisional concept merely to facilitate in bridging a gap of understanding. Consequently, once the way to the new understanding has been shown, the provisional, concept is discarded. In the final analysis, Matthew's emphasis is placed on the disciples who are to do the will of God rather than on the righteous who do righteousness.

That the concept of righteousness was in fact able to function as a significant provisional concept, is supported by its use in the Dead Sea Scrolls and the Tannaitic literature. The present study demonstrates that he component parts of the Matthaean concept of righteousness can be readily understood against the background of the thought expressed in these writings.

abstract: Doctor of Philosophy (PhD)


title: The Synoptic Gospels and the Problem of Genre

contributor:
Sanders, E.P.
Religious Sciences

subject: Religion Religion

abstract:
The single question to which this dissertation is addressed is: to what literary genre do the synoptic gospels belong? The question per se is not a new one; nor is it one which fails to generate scholarly interest from one generation to the next. Nevertheless, it is one which is lacking a satisfactory solution. The essential difficulty with a solution appears to be derived from two sets of data which may be expressed in paradoxical relationship to one another: 1) the synoptic gospels are narratives composed of traditions attributed to Jesus and preserved by the church, traditions which are so presented as to focus upon Jesus' person, and 2) the synoptic gospels appear to have no "biographical intent" (understood in contemporary terms as a primary intent to preserve an accurate, historical account of Jesus). The problem, therefore, is this: the synoptic gospels are in some sense "biographical", but they are not "biographies".

Our own approach to this question begins with a preliminary discussion of the nature of a literary genre. Our conclusion is that the concept itself is broader and more dynamic than contemporary New Testament scholarship has yet accepted. Then, following a brief presentation of presuppositions, the reconstruction and definition of a literary genre, which was current at the time the gospels were written (historical aspect of genre reconstruction) and which is an appropriate category for the synoptic narratives (descriptive aspect of genre), is set forth. This genre is initially referred to as laudatory biography and is later more specifically identified as "encomium" biography. Its existence is posited on the basis of the ancient dichotomy between history and some biographical counterpart: it is defined by reference to the rules of characterization which were codified in the rhetorical rules for the encomium.

The proposition is then tested by a discussion of the synoptic gospels and their affinities with the genre as set forth. The basis of this discussion is as new in this dissertation as is the proposed solution to the initial question of genre. After pointing out the weaknesses of establishing genre relationships by a comparison of one specific text with another, we discuss the affinities of, the synoptic gospels to the "encomium" biography in terms of genre characteristics: namely, topoi, literary techniques, and purposes.

The essential contribution of this thesis is that it presents a reasonable identity and definition for the synoptic gospels as literary wholes. It offers a historical explanation for the paradoxical character of these narratives of Jesus by providing the literary basis for the presentation of a praiseworthy person in a narrative form which was not composed primarily for the purpose of recording events. More important for the exegete, it provides an intelligible whole with which and through which the individual parts may be viewed. This contributes to the "exact" interpretation of the text. Finally, after having identified a proper literary genre which conveys certain meanings and presuppositions, the authenticity of the may now be addressed anew.

abstract: Doctor of Philosophy (PhD)


title: Biochemical and Genetic Approaches to the Study of Mitochondrial Biogenesis in Mammalian Cells

contributor:
Freeman, K.B.
Biochemistry

subject: Biochemistry Biochemistry

abstract:
I. A mammalian cell mutant of the Chinese hamster ovary cell line (designated tsH1) was shown by Thompson et al (1973) to have a temperature-sensitive leucyl-tRNA synthetase. At 40°C, a non-permissive temperature, protein synthesis continued at about 1% of the rate at 34°C, a permissive temperature. The possibility that this synthesis represented mitochondrial protein synthesis was confirmed by the following observations:

a) the protein synthesis at 40°C, but not at 34°C, was sensitive to tevenel, a specific inhibitor of mitochondrial protein synthesis;

b) protein synthesis by isolated mitochondria from tsH1 was not temperature-sensitive;

c) [¹⁴C]leucine incorporation at 40°C was located specificially in the mitochondrial fraction;

d) [¹⁴C]leucine incorporation into the mitochondrial fraction of tsH1 at 40°C was sensitive to tevenel but not cycloheximide;

e) the pattern of mitochondrial proteins synthesized at 40°C on SDS-polyacrylamide gels is very similar to those synthesized at 34°C in the presence of the inhibitor of cytosolic protein synthesis, cycloheximide.

These results, together with the demonstration of three species of leucyl-tRNA in hamster liver mitochondria different from the four cytosolic species (by RPC-5 chromatography), suggest that tsH1 mitochondria contain a unique, non-temperature-sensitive leucyl-tRNA synthetase. This cell line may prove to be very useful in the analysis of mammalian mitochondrial protein synthesis in the absence of inhibitors.

II. Interspecies somatic cell hybrids offer a unique system for the study of interactions between mitochondria and the nucleus. This is possible because one can distinguish mitochondrial components of the parental species, as well as the chromosomes of the parental species. In an attempt to characterize the difference between hamster mitochondrial DNA (mtDNA) and human mtDNA, a comparison of buoyant densities of the two mtDNAs was made. It was found that human mtDNA was more dense than hamster mtDNA by 0.008 g/cc. One human-hamster hybrid cell was examined and found to have mtDNA with a density similar to hamster mtDNA. This result, together with observations reported previously from this laboratory, should now allow the analysis of human-hamster hybrid cells for the maintenance and expression of mtDNA from the parental species.

Protein synthesis in mammalian cell mitochondria is initiated with fMet-tRNA^(met, f), the formyl group being most likely donated by N¹⁰ formyl H₄ folate. Methotrexate, which depletes the C₁-H₄ folate pools by inhibiting dihydrofolate reductase, might block the formylation reaction, inhibiting mitochondrial protein synthesis and indirectly cell growth. L cells grown is suspension culture were found to grow normally in the presence of 5 X 10ˉ⁵ M mathotrexate when supplied with metabolites whose synthesis requires the C₁-H₄ folate pools. Preincubation for 15 min with 10ˉ⁴ M methotrexate does not affect the subsequent formylation of mitochondrial initiator tRNA. Also, there is no effect on the synthesis of N-formylmethionylpuromycin in L cells grown for 160 hr in the presence of 5 x 10ˉ⁶ M methotrexate, nor in KB cells grown for 72 hr in its presence. These results demonstrate that cell growth, the formylation of mitochondrial initiator tRNA and the initiation of mitochondrial protein synthesis are not inhibited by methotrexate when cells are supplied with metabolites whose de novo synthesis requires C₁-H₄ folate pools. The mechanism of continued formylation in the presence of methotrexate is not known.

The thymidine kinase deficient, LMTK cell line incorporates BUdR specifically into mtDNA. The possibility that this specific incorporation of BUdR would induce mutations of the mitochondrial genome was investigated. Preliminary evidence suggests BUdR is effective in increasing the frequency of tevenel resistant cells, however, a large fraction of the LMTKˉ cell population studied ( 4 - 9 x 10ˉ⁵) shows resistance to tevenel without BUdR treatment and these cells have been chosen for study.

After growth in suspension culture for 5 days in 100 μg tevenel/ml and subsequent plating in 100 μg tevenel/ml, LMTKˉ cells yielded resistant clones. As a control, L cells treated identically, yielded resistance clones. Three of the resistant clones were studied. Each resistant cell line had an identical growth rate in the presence and absence of 100 μg tevenel/ml; whereas, LMTKˉ ceased growing after 2 or 3 generations in 100 μg tevenel/ml. By plating efficiency analysis the resistant cells were found to be cross-resistant to D-chloramphenicol. The change responsible for resistance was found to be stable for at least 100 generations in the absence of the drug.

Protein synthesis by isolated mitochondria of resistant cells was found to be less inhibited by concentrations of both tevenel and D-chloramphenicol up to 200 μg/ml than the protein synthesis by LMTKˉ mitochondria. This resistance in vitro was not changed by incubation of the mitochondria in 0.01% Triton X-100.

These results suggest, but do not prove, that the resistant cells are mutants of the mitochondrial genome and that LMTKˉ cells may be important in the isolation of other mutants of mitochondrial function.

abstract: Doctor of Philosophy (PhD)


title: Leo Strauss on Jerusalem and Athens

contributor:
Grant, G.P.
Religious Sciences

subject: Religion Religion

abstract:
This thesis attempts to enucleate the thought of Leo Strauss on the relation of Jerusalem and Athens. The specific focus and special interest of this thesis in Leo Strauss' s investigations of Jerusalem and Athens is the relation of Judaism and philosophy.

The essential assertion of Strauss's position is the fundamental and irreconcilable opposition between Jerusalem and Athens. That fundamental opposition is discerned by Strauss chiefly in the classical conception of philosophy and the "metaphysics" of the Bible, and in the contrast of philosophic morality and the morality of the Bible.

Although evidencing change or "development," Strauss's thought remains centrally concerned with "das theologisch-politische Problem." His early work on Maimonides and his Islamic predecessors, Philosophic und Gesetz, exhibits his concern with the relation of political philosophy and theology, exotericism, the relation of the Law and the natural law, the quarrel between ancients and moderns, the distorting effect of reading pre-modern writers through modern lenses and the inadequacy of modern philosophies of Judaism. The extent and character of Strauss's "development," as well as the abiding unity of his vision, is indicated in viewing his earlier understanding in light of his own later "corrections."

The thesis concludes with Strauss's thematic elaboration of the insufficiency generally of Enlightenment and post-Enlightenment accommodations of Jerusalem and of modern Jewish "movements," in particular.

What is all important to this thesis is the central fact of Strauss's life-long attention to Jerusalem and Athens, to "das theologisch-politische Problem," to Judaism and philosophy. Attention is the essence of the "third alternative" to unreasoned belief and unreasoned unbelief.

abstract: Doctor of Philosophy (PhD)


title: Immunologic Studies on Pichinde Virus Infection in Cell Culture and in Syrian Hamsters

contributor:
Rawls, W.E.
Medical Sciences

subject:
Medical Sciences
Medical Sciences

abstract:
Infection by Pichinde virus, a member of the arenavirus group, was studied in vivo in Syrian hamsters, and in vitro in cell culture. Emphasis in the in vivo studies was placed on the mechanism of resistance to virus infection in adult hamsters. Two hamster strains were found to differ in their susceptibility to lethal Pichinde virus infection. LVG/Lak hamsters were found to be 100% susceptible to low doses of Pichinde virus during the first 6 days of life, but after 8 days of life, mortality was uncommon. Peak serum virus titers in animals infected at 3 days of life were 4 logs greater than in animals infected at 12 days. MHA/Lak hamsters, in contrast, were found to be susceptible to lethal virus infection both as newborns and as adults. Peak serum virus titers of greater than 10⁸ PFU/ml were observed 8 days after infection of adult MHA hamsters compared with less than 10³ PFU/ml in their LVG counterparts. Cultured primary kidney cells and peritoneal macrophages from either hamster strain supported Pichinde Virus replication equally well in vitro. Antibody levels measured by complement-fixation test were similar at 13, 21, and 30 days after infection. Cyclophosphamide immunosuppression, administered 3 days after infection, rendered adult LVG animals susceptible while slightly increasing the mortality among MHA hamsters. These findings suggest that immunologic factors maturing early in life in LVG hamsters and deficient in MHA hamsters limit Pichinde virus infection. The relationship of these observations with previously reported arenavirus diseases is discussed.

The antigenic structure of Pichinde virus was examined. Lysates of BHK₂₁ cells, infected with Pichinde virus and harvested 48-96 hours after infection contained virus-specific antigens detectable by complement-fixation (CF) test. Immunodiffusion analysis of the lysates demonstrated two antigens which differed in their properties of heat and proteolytic enzyme resistance. The antigen accounting for the major proportion of the CF antigen activity was a heat stable, pronase resistent protein of 20-30,000 molecular weight estimated by gel filtration. The minor antigen was heat labile and susceptible to proteolysis. Antiserum prepared against partially purified major antigen, yielded a band of identity when tested against antiserum prepared against virus "cores" obtained by NP-40 solubilization of purified Pichinde virus. Disruption of purified virus by treatment with 1% NP-40 and 50 ug/ml RNase liberated 2 soluble antigens which identified with those demonstrated in lysates of infected cells. The liberated antigenic activity was shown to contain 3 of the 4 polypeptides found in the virion. These findings suggested that the antigens detectable by CF and immunodiffusion were components of the virion core. Major antigen derived from infected cells was purified by rate-zonal sedimentation, isoelectric focusing and gel filtration. Two low molecular weight polypeptides were demonstrable in the purified antigen.

Since multiple segments of RNA exist in the Pichinde virion, it was of interest to determine, whether antigen synthesis and virus production could be dissociated in the infected cells. In Vero cells infected by Pichinde virus, antigen on the cell surface, and production of infectious virus shut down 48-96 hours after infection, whereas antigen detectable in the cytoplasm of infected cells appeared stable for over 5 days. In BHK₂₁ cells, actinomycin D (AD) at dosage levels of 1-4 ug/ml reduced virus yields by greater than 95% while reducing antigen detectable by CF by only 30%. The quantity of antigen produced was independent of AD dosage within the range tested. Both the major and the minor antigens were identified in lysates of AD treated cells. The observed decrease in infectious virus production could not be attributed to increased cell associated virus or to greater production of defective interferring particles. Surface antigen, demonstrable by immunofluorescence and by antibody binding assay was found to accumulate of infected cells incubated with AD. These findings suggest that Pichinde virus replication in AD treated BHK₂₁ cells is blocked at the level of virus maturation.

abstract: Doctor of Philosophy (PhD)


title: Parity Measurements Obtained from the ⁴⁸Ca(đ,α)⁴⁶K

contributor:
Kuehner, John A.
Physics

subject: Physics Physics

abstract:
A polarized deuteron beam was used to initiate a (d,α) reaction on an even-even target with the detection of the reaction products near 0°. A model independent technique is utilized which allows the parity of a nuclear state (natural or unnatural) to be determined from a measurement of the tensor analyzing power T₂₀. In addition, it is possible to identify 0¯ levels uniquely.

This reaction was performed on a doubly-magic ⁴⁸Ca target. The resulting isotope ⁴⁶K may therefore be treated as a proton hole and a neutron hole in a ⁴⁸Ca core. As a result of this simple shell-model picture, several investigations into the spins and parities of the low-lying states of ⁴⁶K have been conducted. However, some of these model dependent assignments have yielded contradictory results - hence the need for this study.

The ⁴⁸Ca(đ,α)⁴⁶K reaction was carried out at 4° with bombarding energies of 7.5, 8.0, 8.5, and 9.0 MeV. For a given beam energy, spectra obtained with the incident deuterons preferentially polarized in the m=0 substate were compared with spectra obtained with polarized deuterons in the m=1 substate. The following parities were deduced from the levels in ⁴⁶K: ground state, 0.69, 1.74, °1.94 MeV levels (unnatural parity) 0.59 and 0.89 MeV levels (natural parity). In addition, a tentative natural parity assignment was made to the 1.37 MeV state. The resulting spin-parity combinations are found to be consistent with the most recent set of measurements by Daehnick et.al.².

Pandya calculations were made in which the order and separation of the lowest levels of ⁴⁰K were obtained from the ⁴⁶K levels. As a result of configuration mixing, the calculations bear little resemblance to the experimental ⁴⁰K spectrum. A discussion of configuration mixing effects is also provided.

abstract: Master of Science (MS)


title: Enhancement of Cooperative Cross-Polar Radar Targets

contributor:
Haykin, Simon
Electrical Engineering

subject:
Electrical and Computer Engineering
Electrical and Computer Engineering

abstract:
A polarimetric radar navigation (PRAN) system makes use of a specially modified marine radar and polarization rotating twist-grid retroreflectors in order to navigate a confined waterway, even in inclement weather or after dark. Despite the polarization diversity offered by such a radar target, depolarization allows significant cross-polar clutter to obscure the reflector return. The objective of the thesis is to successfully demonstrate the enhancement and detection of a cooperative cross-polar target.

A field experiment is designed in Hamilton Bay, and 28 scans of real-time non-coherent HH-pol and HV-pol radar video recorded in a digital format from atop the Canadian Centre for Inland Waters, in Burlington, Ontario. The two reflectors are located at sites in the Dofasco area and the La Salle Park area. A conventional cell-averaging CFAR processor is initially used to give a benchmark against which to compare joint signal processing methods. A dimensionless normalized target-to-clutter ratio (NTCR) is introduced to quantify performance, along with standard sub-images to subjectively show the effect of the processing.

An adaptive cross-polar interference canceller is designed which processes the dual-polarization channels jointly, reducing the nonstationary clutter variance and enhancing the target. An analog implementation of the processor was granted Canadian and U.S. patents.

In another approach, mutual information based unsupervised learning of linear and nonlinear networks is investigated. The RBF network is shown to greatly enhance cross-polar reflector response in the non-Gaussian statistical environment.

Next, a modular solution integrates all three methods to produce superior reflector enhancement in average and peak clutter.

Finally, a novel post-detection processor is demonstrated that successfully uses a priori information about the reflector location along the water-land boundary of the waterway. A fuzzy processor combines primary detection information with the output from a vision-based edge detector to effectively remove false alarms.

abstract: Doctor of Philosophy (PhD)


title: Scheduling and Frequency of Knowledge of Results Presentations: Age-Related Effects on Motor Learning

contributor:
Streiner, David
Medical Sciences

subject:
Medical Sciences
Medical Sciences

abstract: Changes in motor control processes associated with advancing age have been the focus of considerable research interest. However, the effect of age on the processes involved in motor skill acquisition have received little attention. In this thesis, two experiments are reported that examine the differences in motor learning between young and older normal adults. The strategy was to evaluate the age-related effects on learning of knowledge of results (KR) variables. The learning task in both experiments was a multisegment task with spatial/temporal requirements. The KR variables evaluated were, (1) random and blocked KR schedules, and (2) different schedules of relative frequency of KR. In general, while the findings indicated large performance differences between age groups, there was no difference between age groups in how the KR variables were used to learn the task. The results suggest that despite declines in performance that accompany age, there seems to be no decline in the capabilities of older adults to use these KR variables to acquire and retain this motor skill.

abstract: Doctor of Philosophy (PhD)


title: Integrated Receiver Array System for Digital Beamforming

contributor:
Litva, J.
Electrical and Computer Engineering

abstract:
A C-band four-element integrated receiver system for digital beamforming (DBF) has been designed and implemented. For an array with digital beam processing, as a means of achieving precise pattern control (low sidelobe, adaptive nulling and high resolution) over large bandwidth and large dynamic range, the use of self-calibration techniques and circuitry was studied and evaluated. A multilayer linear self-calibration loop was also suggested and developed. Furthermore, in this thesis, the use of active antennas and optically controlled microwave devices in DBF systems was investigated.

Integrated antennas, as the first stage of the whole DBF system, are required for overcoming excessive power loss in large microstrip array antennas, for avoiding degraded array far-field pattern performance due to spurious radiation from microstrip feed networks and for larger effective isotropic radiated power (EIRP). The possibilities of using active antennas instead of conventional passive antennas are studied. Several new active antenna structures were proposed and implemented. Detailed design procedures and experimental results were given. Other applications for spatial power combiners and larger active antenna arrays were also addressed.

The optical control of microwave devices and subsystems is a rapidly growing area of research. In this thesis, the possibilities of using optical control in DBF systems are discussed. This thesis also describes the first reported application of frequency-dependent finite-difference time-domain ((FD)²TD) method for modelling optoelectronic microwave semiconductor devices. The two major effects of a constantly illuminated semiconductor plasma which must be analyzed are: (i) the strong influence of carrier diffusion and recombination-generation processes on photoconductivity and (ii) the depth to which the plasma penetrates the device. Two examples of using modified (FD)²TD method to analyze a two-dimensional optically controlled dielectric resonators and three-dimensional optically controlled phase shifters/attenuators are presented. Finally the comparison between available experimental results and theoretical results are discussed.

abstract: Doctor of Philosophy (PhD)


title: On the Application of Multi-Layered Perceptrons to Nonlinear Equalization for Frequency Selective Fading Channels and Nonlinear Prediction for Time Selective Rayleigh Fading Channels

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

abstract:
We show that in the additive white Gaussian noise channel that a single neuron using the standard sigmodial nonlinearity function is effectively a Bayesian estimator for a binary (±1) level signal and establish a link between the weight(s) of the neuron and the noise variance associated with the signal. This relationship is then extended to neurons where the sigmodial nonlinearity function incorporates a gain term. By extending these results to multi-level signalling we develop a new nonlinearity function that incorporates a gain α which simplifies the structure of the neural network. We show that this gain term in linked to the noise variance much like the gain term in a neuron using sigmodial nonlinearity for binary signalling.

In applying neural networks to the channel equalization problem for frequency selective fading we make use of complex neurons in the neutral network. We look at both binary signalling in two dimensions, and higher level signaling as well. Our results show that while neural nets provide a significant performance increase in the case of binary signalling in two dimensions this performance is not reflected in the results for the higher level signalling schemes. In this case the neural net equalizer performance tends to parallel that of the linear transversal equalizer.

Under the Rayleigh fading channel, we demonstrate the feasibility of using a simple neural network as a phase predictor to significantly reduce the error rate for quadrature phase shift keying signalling in this channel. With this network it is possible to remove the error floor that is normally encountered in this channel for average signal to noise ratios of less than 60dB.

abstract: Doctor of Philosophy (PhD)


title: Repetitive Learning Control of Robotic Manipulators

contributor:
Sinha, Naresh K.
Electrical and Computer Engineering

abstract:
This thesis deals with the repetitive learning control of robotic manipulators. The research topic is motivated by the fact that industrial robots usually perform repetitive tasks. Unlike other conventional controllers, the repetitive learning controller can improve the performance of a robot as it repeats the same task. The proposed control strategy has advantages of easy implementation, low cost and better performance. A critical survey of the state of the art in repetitive learning control of robots is presented. This thesis is divided into two major parts: a two operational modes based approach and a neural network based scheme.

In the first part of the thesis, a theoretical framework has been developed for designing controllers based on the proposed two operational modes. The repetitive operations of a robot can be divided into two operational modes: a single operational mode and a repetitive operational mode. Based on this, the author proposes repetitive learning schemes for motion control of both rigid and flexible joints robots, as well as for control of constrained robots with rigid joints. The designed controllers converge in both operational modes. In the single operational mode, the controllers behave like adaptive controllers, while similar to a betterment process in the repetitive operational mode. These conclusions are firmly supported by simulation studies.

In the second part of this thesis, special attention is paid to schemes based on neural networks. The author's own modification of back-propagation neural networks is first established in the thesis. It is then applied to motion control of both rigid and flexible joints robots, as well as force control of rigid robots. The neural networks play the role of an approximate inverse dynamic model of a robot and are then parallelled with a conventional PD controller to achieve control goals. Very promising results have been reported in this thesis.

abstract: Doctor of Philosophy (PhD)


title: In Vivo and In Vitro Mechanisms of Ozone Induced Canine Airway Hyperresponsiveness

contributor:
O`Byrne, P.M.
Physiology and Pharmacology

subject:
Pharmacy and Pharmaceutical Sciences
Pharmacy and Pharmaceutical Sciences

abstract: Heavy water moderated thermal nuclear fission reactors have a greater inherent neutron economy than light water or graphite moderated reactor designs. Consequently, such units, operating on a variety of fuel cycles, may play an ever-increasing role in meeting future global energy demands. This thesis explores, analytically, the operational advantages and challenges associated with the use of a low enriched uranium (LEU) fuel cycle in advanced reactors based on the CANDU heavy water moderated, pressure tube design concept. The flexibility afforded through the use of LEU fuel is applied to enhance the operational and safety characteristics of reactors utilizing this fuel cycle. An investigation of factors influencing coolant void reactivity is conducted. Design modifications are introduced to reduce the coolant void reactivity, while maintaining the continued capability of high power operation. An enrichment and element radius graded fuel bundle design is developed with a central graphite core, an inner ring of 14 fuel elements, and an outer ring of 21 fuel elements. Fuel and lattice design perturbations are investigated to examine the effect of lattice pitch variations, capability of radioisotope production, the use of burnable poisons, and light water coolant. Xenon override requirements with LEU fuel are addressed. The efficacy of using modified two group (M-2) neutron diffusion theory for LEU fuel management studies is investigated. A modelling strategy is developed for the simulation of reactivity devices and fuel lattice properties using the M-2 methodology with a fixed energy cut-off. Detailed fuel management studies are conducted to examine the operational intricacies of LEU fuelling. Improved checkerboard type fuelling strategies are developed. Finally, the CANDU - Spectral Shift Advanced Thermal Reactor (CANDU-SSATR) is introduced and characterized. This multi-spectrum high burnup advanced reactor design utilizing simplified fuel management strategies holds great promise for the future.

abstract: Doctor of Philosophy (PhD)


title: Haldane's Rule and the Genetic Basis of Hybrid Male Sterility in Drosophila Simulans, Drosophila Mauritiana and Drosophila Sechellia

contributor:
Singh, Rama S.
Biology

subject: Biology Biology

abstract:
Genetic analysis of hybrid sterility and inviability has recently become a successful experimental approach to pursue the problem of speciation. In the present study, classical genetic analyses and high resolution two-dimensional gel electrophoresis (2DE) have been used to investigate the genetic basis of hybrid male sterility in three sibling species of the Drosophila melanogaster species subgroup. The genetic basis of Haldane's rule, i.e., the preferential hybrid sterility and inviability of heterogametic sex, is also examined. The D. sechellia Y chromosome was shown to have no effect when placed in the background of D. simulans. This shows that the X-Y interaction hypothesis can not be a general explanation of Haldane's rule. Cytoplasmic factors were shown to have no effect on hybrid male sterility between D. simulans and D. mauritiana and between D. simulans and D. sechellia. An asymmetric X-autosome interaction provides the best explanation of hybrid male sterility between D. simulans and D. sechellia. The asymmetric model of X-autosome interaction can also explain the asymmetries (unidirectionality) in reproductive isolation commonly observed between related species.

Testis protein divergence on X chromosome was shown to be smaller than that on autosomes between these species. This implies that Haldane's rule may not be accounted for by a faster evolution of the X chromosome. The number of genes involved in hybrid male sterility between D. simulans and D. sechellia was shown to be small by using 2DE. A few D. sechellia specific testis proteins were identified to be consistently associated with male sterility.

A general method for detecting major hybrid male sterility genes has been introduced. By using this method, a single Mendelian factor of D. mauritiana which produces complete male sterility in the background of D. simulans was identified and mapped to the X chromosome.

abstract: Doctor of Philosophy (PhD)


title: The Harmonic Oscillator Approximation to the Density Matrix

contributor:
Bhaduri, Rajat K.
Physics

subject: Physics Physics

abstract:
We derive an approximate form for the angle averaged single particle density matrix for particles in a central potential. It is a Taylor series expansion in the interparticle distance |S| based on the exact density matrix for particles in a harmonic oscillator potential. This form is also shown to be exact for particles in a linear and quadratic potential in one dimension.

We show the relation between this approximation and previous ones derived by Negele and Vautherin, Campi and Bouyssy, and Jennings. All these approximations agree with the exact angle averaged density matrix up to the S² coefficient of their respective Taylor series expansion in |S|. We compare the coefficients of S⁴ and higher powers of S within each approximation to show the connections between them.

We then check, numerically, the S⁴ coefficients of the various approximations with the exact coefficient. In one dimension we use the Eckart potential and in three dimensions we use the Woods Saxon. All three give reasonably good approximations to the exact S⁴ coefficient, with the exception of the Negele Vautherin form in one dimension.

Suggestions for putting the harmonic oscillator approximation into a form amenable to calculating exchange integrals are made.

abstract: Master of Science (MS)


title: An Internal Friction and DSC Study of the Cu-Zn-Al Shape Memory Alloys

contributor:
Johari, G.P.
Materials Engineering

subject:
Materials Science and Engineering
Materials Science and Engineering

abstract:
The temperature and time dependence of the thermoelastic martensitic transformation in Cu-Zn-Al shape memory alloys have been studied by means of internal friction, DSC (Differential Scanning Calorimetry), X-ray diffraction and metallography. A physical model and mathematical treatment have been developed to derive an expression for internal friction associated with the thermoelastic martensitic transformation. This expression has been able to explain the amplitude dependence of the internal friction in various ranges of stress amplitude, where other theories have failed. In the special case where the applied stress amplitude is much higher than the critical stresses for the stress-induced martensitic transformation, the internal friction is found to be linearly proportional to the reciprocal of the stress amplitude, in good agreement with the experimental results. The time evolution of internal friction and shape change has been measured simultaneously in different microstructural states of the shape memory alloys. In the single-martensite phase state, the monotonic decrease of internal friction with time, without any accompanying shape change, has been attributed to the progressive pinning of the martensite/martensite interfaces. When the parent phase is present, the appearance of an internal friction peak, accompanied by an evident shape change, is found to be associated with the stress-induced martensitic transformation and the subsequent pinning of the martensite/parent and martensite/martensite interfaces.

The effects of aging in both martensite and parent phases have been studied. Aging in parent phase caused the precipitation of $\alpha$-phase which hindered the subsequent martensitic transformation and resulted in a suppressed internal friction peak and a deteriorated DSC peak. Aging in the martensite phase resulted in the pinning of the martensite/martensite interfaces by vacancies, which significantly obstructed the subsequent transformations upon heating and cooling. This has been evidenced by both internal friction and DSC measurements.

abstract: Doctor of Philosophy (PhD)


title: A Quantitative Study of the Organization and trophic regulation of cutaneous mechanoreceptors in the salamander

contributor:
Diamond, J.
Medical Sciences

subject:
Medical Sciences
Medical Sciences

abstract:
Partial denervation of a shared target tissue leads to 'collateral' sprouting of the remaining nerve fibres supplying the same region. The mechanisms responsible for this widespread phenomenon are unknown, but it has generally been believed that products from the degenerating fibres constitute the sprouting stimulus. Recently it was shown that a similar sprouting of intact nerves occurred in the salamander hind-limb when the axoplasmic transport in one of the neighbouring nerves was blocked by colchicine. This block did not, however, appear to interfere with the functioning of the treated nerve. On this evidence it was proposed that nerves release factors which are concerned in the regulation of their peripheral fields. The experiments of this thesis test this hypothesis further. In particular this study quantitatively examines the organization of the cutaneous mechanoreceptors of the salamander hindlimb, and the effects of various nerve treatments on this organization.

A mechanical prodder of 10-50μ tip diameter was used to determine the sensory threshold of the skin at selected spots. The mechanoreceptors were found to be all rapidly-adapting. An analysis of the distribution of their thresholds across the skin points to the existence of a single population of mechanosensory endings of similar threshold which are fairly uniformly distributed in the plane of the skin. A simple model, based on the results, indicates that these receptors have receptive field sizes of about 50μ, and are spaced approximately 150-200μ apart. Direct inspection of data from systematically surveyed skin areas gave findings which were consistent with these estimates. These quantitative results made it possible to establish that the blocking of fast axoplasmic transport does not affect the sensitivity or distribution of the individual mechanosensory endings of the treated nerve. Nevertheless new sprouts appeared from the adjacent nerves, and it seemed that there was a tendency for these to grow preferentially to the site of the still-functioning endings of the treated nerve. Most significantly, after partial denervation of the skin the number of newly sprouted endings quantitatively matched the number of endings lost by nerve section.

It was concluded that there is a control mechanism which continuously regulate the density of the skin innervation. This control system probably involves the mutual interaction of substances continuously secreted from the target tissue, which cause nerves to sprout, and factors released from the nerve endings which offset the effects of the growth stimulus. The nerve field density reflects an equilibrium state between the neural and tissue influences.

abstract: Doctor of Philosophy (PhD)


title: Choosing Methods of Conflict Resolution: Is Individualism-Collectivism the Key?

contributor:
Carment, D.W.
Psychology

subject: Psychology Psychology

abstract:
Researchers examining the influence of the individualism-collectivism value dimension on procedural preferences for conflict resolution (e.g., Leung, 1987; Leung, Bond, Carment, Krishnan, & Liebrand, 1990; Leung & Lind, 1986) have suggested that people from individualistic societies tend to prefer adversarial procedures such as arbitration, while collectivist persons tend to prefer bargaining and mediation. However, almost all of these collectivistic samples were drawn from Oriental societies where some unique values such as the Confucian work dynamism also have been identified. These values may independently influence preference. To replicate these results in non-Oriental societies, college students from both Canada (an individualistic society) and Nigeria (a collectivist society) were asked to indicate their preferences for using threats, accept the situation, negotiation, mediation, and arbitration procedures. The participants also completed Hui's (1988) Individualism-Collectivism Scale (INDCOL).

The outcomes did not support the previous research. Canadian subjects showed a stronger preference for negotiation and mediation than Nigerian subjects who, in addition to indicating a greater tolerance for threats, also tended towards arbitration. The INDCOL results also were unexpected; relative to the Nigerian subjects, Canadian subjects were collectivist on the parent and coworker subscales while Nigerian subjects were collectivist on the neighbour subscale. Because the scenarios in the first study were constructed without anticipating that certain domains of individualism and collectivism could exist within the same culture, interpretation of the above results became problematic.

This problem was addressed in two subsequent studies which compared Canadian and Nigerian students on the three domains of individualism-collectivism in which they differed. To this end, Canadian and Nigerian subjects were asked to indicate their preference for methods of resolving a parent-child dispute, a dispute between neighbours, and a third dispute between coworkers. Because Canadians had been found to be more collectivist on the parent and coworker subscales, it was hypothesized that they would prefer negotiation and mediation over arbitration in resolving these conflicts while Nigerians would prefer to use arbitration in the same situation. Conversely, Nigerian subjects were expected to show greater willingness to use negotiation and mediation in resolving a conflict involving neighbours and Canadian subjects were expected to be more inclined toward arbitration. A subsidiary interest was to investigate whether or not people prefer to use different procedures in resolving interpersonal than in resolving intergroup conflicts.

The major hypotheses were confirmed. Canadians were more willing than Nigerians to use negotiation in the parent-child and coworker conflicts while Nigerians showed a greater willingness to use arbitration in both situations. The contradictory finding was the higher ratings by Nigerians on mediation in the parent-child conflict. In the neighbour conflict, Nigerians were more willing to use negotiation while Canadians were more willing to use arbitration. Furthermore, when subjects were divided into high and low scorers on the parent subscale (culture/nationality ignored), a similar pattern of results as described above was obtained.

The analysis of the type of conflict variable revealed that arbitration is preferred to a greater extent in resolving intergroup than interpersonal conflicts. Implications of these findings for the theory of procedural preference and practice of conflict processing are discussed.

abstract: Doctor of Philosophy (PhD)


contributor:
John C. Robertson, Jr
Going, Cathleen M.
Religion

subject: Religion Religion

abstract:
As the title (Complete Intelligibility: A Study of Bernard Lonergan's Argument for the Existence of God) suggests, the focus of this dissertation is an argument. The argument runs: If the real is completely intelligible, God exists; but the real is completely intelligible, therefore, God exists. This argument is studied and discussed in two ways: expositionally and critically.

In the expositional part, I seek to explain the argument in such a way that, on the one hand, the reader unfamiliar with Lonergan's thought may become apprised of its main lines and, on the other, the reader familiar with Lonergan's thought may see more clearly how the argument is continuous with other parts of Lonergan's thought, notably with his cognitional theory. It becomes clear in the expositional part, for example, that Lonergan's conception of complete intelligibility as an unrestricted act of understanding (which, on analysis, has the properties of what is meant by the name "God") is closely related to what Lonergan sees at the heart of human knowing, viz. a pure, unrestricted desire to know.

In the critical part, I submit each premise of the argument, as well as the concept of God which emerges from the major premise, to a dialectical scrutiny. That is to say, on the one hand I determine and represent the major types of challenges to which the premise or concept is susceptible and, on the other, I draw on the resources of Lonergan's thought to offer a Lonerganian response. In so doing I beiieve that I not only test the argument in a way that it has not been tested but I also single out points of departure for ongoing critical inquiries and I provide the wherewithal for at at least a provisional personal judgment. One such judgment is given in the concluding chapter. In it I express qualified approval of the argument.

Lonergan's argument is transcendental, in the sense that its affirmations are uItimately based on notions discernible in the data of consciousness. The present study both brings out this transcendental character and deals with the objection that this approach cannot go as far as Lonergan would have it go. This is done by both by a reflection upon Lonergan's claims and by a reflection upon our consciousness as we examine these claims. In other words, the study not only discusses Lonergan's transcendental approach. It also, at least in part, illustrates it.

I cannot say whether I have discovered, in this study, anything which Lonergan himself has not discovered. I have, however, made explicit and manifest certain ideas which are present in Lonergan's writings only implicitly or as a latent tendency. For example, as far as I know, Lonergan has not addressed at any length the question whether his argument confuses the desirable and anticipated with the real and actual. To this question, I believe I offer a cogent, if not totally convincing, response from a perspective engendered by Lonergan's thought, a response centering on the unique character and role of the desire to know.

whether his argume:lc1t confuses the' desirable,~d ant~cip~t~d , :, '. . . ..withther~aiancl'actual.. !!!o this quest.i.~ntlbelieyeI· , .' offer aC9gent, if nO,t totally convincing; response from ",,\ , ',,' a perspective "engendered by ,Lonergan's thought, a res~onse . ,. ",., . , centeI'ing on the unique cha.racte; and role of, the desire /,- to know.,

abstract: Doctor of Philosophy (PhD)


title: Localization to the Nuclear Envelope and Transport of the Glycoprotein B of Herpes Simplex Virus Type 1

contributor:
Ghosh, Hara P.
Biochemistry

subject: Biochemistry Biochemistry

abstract:
Herpes simplex virus type I (HSV-1), acquires its envelope by budding through a modified inner membrane of the nuclear envelope (NE) which forms thick and dense patches at the site of budding. This suggests that some of the viral envelope constituents, such as the transmembrane glycoprotein B (gB), are specifically transported to the NE in order to be incorporated into the virus. In this thesis, it is shown by immunoelectron microscopy that gB is specifically localized in the NE of HSV-1 infected cells. Glycoprotein B was distributed on the outer and inner membrane of the NE. The distribution was homogeneous and no preferential accumulation was detected around or within the patches where the viruses bud.

To determine which segments specify NE localization of gB, the distribution by immunofluorescence and by immunoelectron microscopy of deletion mutants and chimeras were investigated by transient expression in COS cells. The rate of transport and the oligomeric nature of the mutants were also studied. The chimeras were constructed by fusing domains of gB with domains of glycoprotein G of vesicular stomatitis virus, a transmembrane protein which does not accumulate in the NE. When the ectodomain (EC) of G was replaced with the EC of gB, the resulting chimera did not accumulate in the NE. On the other hand, all the mutants containing a peptide of 75 residues that encompasses the TM of gB were localized to the NE, suggesting that the TM contains the NE localization determinants. However, this domain does not appear to be essential, because swapping the TM of gB for the TM of G did not abolish NE localization. Furthermore, gB and all the mutants that were localized to the NE were also present in the ER suggesting the presence of an ER localization signal as well.

abstract: Doctor of Philosophy (PhD)


title: The Creation Motif in the Book of Job

contributor:
Combs, A. E.
Religious Sciences

subject: Religion Religion

abstract:
The Hebrew version of Job (BH³) is the authoritative text in this investigation of the creation motif in the book. Although the authenticity of the many textual and other problems with which this book is replete is not disputed, nevertheless it is legitimate to treat the work as a unit since it has existed as such for many generations. The proper appreciation at the role and significance of the creation motif in Job provides a convincing explanation of the book taken as a whole.

The nature of the creation motif in Job is complex. It include notions of kingship, temple-building, conflict with chaos and with mythological monsters. These ancient Near Eastern notions of creation are adapted in this book to meet Hebrew requirements. The motif as it appears in Job also contains reflections on Genesis 1 and 2 and on other sources or creation thought in the Bible. The essence of the motif is the relationship of God to man in creation. It is this relationship which provides the subject matter for the poet's speculation.

The function of the creation motif in Job is to assert the poet's belief in the potency and significance of the divine self-disclosure in the realm of creation. Job, who is deprived at all that could then be expected to make life tolerable, is also robbed of the comforts contained in the proper observance at conventional morality and correct religious behaviour. The source of true religion is the fulfilment of the Law, as the friend repeatedly assert. Because Job suffers the friends assume that he has sinned. But Job is convinced that he has not transgressed the Law. Consequently, he is forced to look elsewhere for an explanation of his adversity. His search eventually meets with success when Yahweh reveals himself to Job in the final scenes of the book. In them Job's relationship to God is restored. He recognizes his part in the divinely ordered creation. Job's belief that it is possible to know God outside the pale of the Law is vindicated. Creation provides the milieu for that knowledge. However, as the terms of the theophany indicate, that knowledge is not attained solely by individual effort, but is partly revealed by God himself to persons suitably prepared.

The book has many functions, but chief among them must be counted the stress on the importance of the creation as a source of revelation as distinct from that of the Law. The book may also be seen as an elaborate polemic against contemporary creation myths and their protagonists. Job is a celebration of the belief that existence is ordered by a benevolent and knowable God and is not subject to the control of chaos. In that existence the filial relationship between the creator and the created is confirmed. The association of man with God in creation offers countless possibilities for wisdom. The same opportunities may not exist for a life circumscribed by the directives of the Law. In sum, the function of the creation motif in Job is to explore the significance of the divine-human relationship as it is revealed in creation.

The conclusion of this investigation is that the proper appreciation of the creation motif in Job makes tolerable sense of the whole work. Creation is important to Job because it provides him with a means of relating to God which was not possible under the Law. It follows that the poet has & higher regard for the usefulness of creation as a source of relation than for the Law itself. The notion of God's acting in history (Heilsgeschichte) also takes second place to his belief in the importance of creation. It is conceivable that the poet is emphasizing the revelatory content of creation at a time when other notions of the nature of God were in decline or disrepute. Alternatively, and more probably as far as Job is concerned, the post regarded creation as the supreme scenario in which revelation takes place.

abstract: Doctor of Philosophy (PhD)


title: Studies on the Degradation of Dihydrofolate Reductase and Other Intracellular Proteins by Mammalian Cells

contributor:
Hillcoat, B.L.
Biochemistry

subject: Biochemistry Biochemistry

abstract:
The mechanisms by which mammalian cells degrade intracellular proteins have been investigated. Radioactively labelled proteins of rat hepatoma tissue culture cells were incubated in cell-free systems in an attempt to identify the degrading processes. Although proteins in intact cells are degraded to their constituent amino acids, little acid-solube material was produced from the labelled proteins at neutral pH, even in cell homogenates which contained all the cellular components.

Dihydrofolate reductase from a subline of the L1210 lymphoma was radioactively labelled and used as a model protein so that changes in a single protein could be investigated. The enzyme was inactivated during incubation with homegenates of the same cell line. Little inactivation was produced by the 100,000 x g supernatant while inactivation was rapid during incubation with the 27,000 x g pellet which contains mitochondria lysosomes and microsomes, or with the 100,000 x g pellet which contained microsomes.

Column chromatography on Sepharose 2B showed that inactivation of dihydrofolate reductase was accompanied by its incorporation into material of high molecular weight. Since inactive enzyme was recovered in several fractions of the column eluate corresponding to the elution volume of the proteins of the subcellular membranes, this material probably represented enzyme which was inactive and bound to these membranes. Greatest binding occurred with membranes of the microsomal fraction.

The formation of inactive enzyme of high molecular weight did not depend on prior denaturation of the enzyme nor on prior proteolytic cleavage since no significant production of acid-soluble material, change in molecular weight or change in the charge could be demonstrated. Treatment of the inactive enzyme with urea resulted in reactivation, again suggesting that extensive modification of the enzyme by proteolysis did not occur.

Binding of the enzyme to microsomal membranes was not reversed by dilution or by the addition of cofactor and methotrexate. Methotrexate, an inhibitor of dihydrofolate reductase, increases the levels of the enzyme in the cells of patients with cancer treated with the drug, possibly by stabilization against degradation. When methotrexate was present during incubation of dihydrofolate reductase with the subcellular membrane fraction inactivation and binding of the enzyme to microsomal membranes was decreased.

The suggestion is made that binding to microsomal membranes could represent the initial step in the degradation of proteins in intact cells. Lysosomes contain proteases and are a likely site of degradation of intracellular proteins. The failure to demonstrate degradation in broken cell preparations could be due to proteins not being able to enter lysosomes. These organelIes are formed from vesicles of the Golgi apparatus. It is suggested that by binding to membranes of the microsomal fraction in intact cells, intracellular proteins could be incorporated into lysosomes at the time of their formation.

abstract: Doctor of Philosophy (PhD)


title: A Study of SnO₂: Preparation, Characterization and Response to Ion-impact

contributor:
Kelly, Roger
Metallurgy and Materials Science

subject:
Materials Science and Engineering
Metallurgy
Materials Science and Engineering

abstract: SnO₂ films have been prepared by reactive sputtering in an oxygen-containing glow discharge, by ion-beam sputtering in an accelerator, and by anodizing with an ethylen-glycol-based electrolyte. Preparation of SnO₂ films by bombarding metallic tin with oxygen ions has also been attempted. The sputter-deposited films were amorphous if deposited on KCl or Ta at temperatures from -100° to +200°C, though they were crystalline if deposited on SnO₂ at 200°C. The anodic films were variously crystalline or microcrystalline, though clearly not amorphous. Films formed by bombarding metallic tin with oxygen ions turned out to be crystalline α-SnO at all doses from 1 x 10¹⁵ to 3 x 10¹⁷ ions/cm². The crystallization temperatures ranged from <200°C for crystalline SnO₂ substrates, to 250°-300°C for KCl substrates, to 400°-450°C for Ta substrates, to 475°-550°C for unsupported films. The crystallization product was consistently cassiterite, i.e., normal SnO₂. Once crystallinity was attained in unsupported sputtered films, the grain size remained in the vicinity of 400 Å to a temperature of about 1000°C. This is in good agreement with the behaviour of anodic films; which retained their microcrystalline structure in heat treatment again until a temperature of about 1000°C was reached. The thickness of the reactively sputtered films was estimated from the observation of their interference colours when deposited on a Ta substrate, while the thickness of the anodic films was estimated by sputtering the films with 20-keV Kr ions until metal was exposed and noting the weight change. The anodization of Sn has a rather low efficiency (4-21%), and this could be shown to be due to electronic conduction rather than dissolution. Kr-ion bombardment of SnO₂ thin films has shown that this oxide presents a very high value of the sputtering coefficient (21.5 ± 1.5 atoms/ion for 10-keV Kr impact), a result which can be attributed to thermal sputtering (i.e., bombardment induced vaporization). As far as the structure of the target material after bombardment is concerned, the experimental evidence was that SnO₂ undergoes amorphization. The effects of ion bombardment of bulk samples (either SnO₂ sintered powder or natural cassaterite) were investigated using the following techniques: (I) reflection electron diffraction, (II) marker-release spectrometry, (III) dissolution measurements, and (IV) resistivity measurements. Through the use of techniques I and II we have established that the annealing (to the original singlecrystalline phase) of bombardment induced amorphousness occurs in two stages: (i) a homogeneous transformation to a polycrystalline phase showing the normal cassiterite structure; (ii) epitaxial recrystallization to single-crystal cassiterite. Dissolution measurements have established the depth of amorphization due to ion bombardment, while resistivity measurements have indicated that bombardment does not cause SnO₂ to change its stoichiometry. Finally the various results allowed us to expand the formalism on which marker-release spectrometry is based, namely we have identified a previously overlooked release process (Stage IC) due to epitaxial crystallization.

abstract: Doctor of Philosophy (PhD)


title: Evaluation of the Cellular and Humoral Immune Response of the Hamster to Simian Virus 40 Tumors

contributor:
Dent, Peter B.
Medical Sciences

abstract:
The SV40 virus system has been extensively investigated as a model for the study of antigens and immune responses to such antigens associated with oncogenesis. While there is considerable data available on the nature of resistance to autochthonous and transplantable tumors in this system, there is very little information on the mechanisms of progressive tumor growth. To evaluate the role of serum factors on progressive tumor growth, an in vitro assay of cell-mediated cytotoxicity using peripheral blood lymphocytes as effector cells and a transplantable SV40 induced tumor (HSO) as the target cell was adapted to the hamster SV40 system. Progressor, immune and post-excision peripheral blood lymphocytes caused a significant reduction in the number of target cells as compared to normal peripheral blood lymphocytes. The cytotoxicity was specific as there was no significant difference between the cytotoxic effect of 'immune' and normal effector cells when tested against unrelated normal and malignant target cell lines. In marked contrast, the cytotoxicity demonstrated by peritoneal exudate cells was non-specific as significant cytotoxicity could be demonstrated on both related and unrelated malignant cell lines.

Serum from hamsters with progressively growing tumors either transplantable (H50 cells) or autochthonous virus induced, did not block, neutralize or enhance in vitro lymphocytotoxicity. However, serum taken from hamsters prior to the appearance of a palpable tumor enhanced the cytotoxicity of immune lymphocytes. Serum from hamsters hyperimmunized with irradiated H50 cells, live SV40 virus, or following SV40 virus, or following complete excision of a growing tumor caused enhanced cytotoxicity of immune and normal lymphocytes. Serum alone was not cytotoxic suggesting an antibody dependent cellular cytotoxicity effect. Serum from hamsters in which tumors recurred after excision was capable of abrograting in vitro lymphocytotoxicity. The inability of progressor serum to enhance or abrograte in vitro lymphocytotoxicity cannot be explained on the basis of preferential absorption of these serum factors by an enlarging tumor mass as low pH tumor eluates could not enhance or abrograte in vitro lymphocytotoxicity.

The activity of immune serum in this study directly parallels the cytostatic antibody activity described by Coggin et al in the hamster SV40 system. These results suggest that progressive primary tumor growth in this system may correlate with a lack of antibody dependent cellular cytotoxicity rather than blocking factors, while the latter may be associated with recurrent and/or metastatic disease.

abstract: Doctor of Philosophy (PhD)


title: The Agrarian Response in Prairie Canada to Industrialization and Urbanization: 1900-1935

contributor:
Blumstock, Robert E.
Sociology

subject: Sociology Sociology

abstract:
Just as the period after 1871 has been described as the era of the sturdy yeoman, as that period in Canadian history interspersed between the days of early settlement and the industrial revolution, the thirty-five year span from 1900 can he delineated as an age of cyclical fluctuation between hardship and prosperity as a trend toward urbanization and industrialization accelerated. One segment of the population affected to a significant degree by these changes was the prairie grain producer, whose existence was influenced most dramatically by needs to adapt to changing circumstances while at the same time safeguard the status of agriculture and rural life from the encroachments of urban and industrial values. What evolved from this situation was the development of a spirit of protest which reflected disaffection with a national tariff protection policy of domestic industry and the monopolistic practices of the railroads, grain companies, financial institutions, and middlemen. In short, grain producers and their organizations pointed to the uncontrolled power of eastern manufacturing, industrial, and political interests in fostering an unstable prairie economy and maintaining the West's political subordination to the East.

Essential to determining the nature and implications of farmers' actions during this period of heightened grievance are the processes by which a distinctive and identifiable agrarian belief system arose and was coalesced through organizational participation. Within one-crop producing areas, low prices, the relatively high cost of manufactured goods, and high capital costs combined to magnify the vulnerability of middle-income grain farmers and to lead them toward demands for fundamental reforms. The study, therefore, focuses to a considerable extent on the historical roots of the farmers' economic and political efforts to control a dependency on the vicissitudes of a domestic and world market while rendering accountable an institutional structure centred in the industrial East.

Two distinctive patterns emerged from these efforts. A shrewd awareness of the techniques of agricultural improvement, business methods, and pressure politics attests to the successes the agrarian movement achieved; conversely, the failures it encountered in reaching a consensus on the means of attaining its goals can be attributed in part to what Richard Hofstadter has labelled the "soft side" of the farmer's existence - agrarian "radicalism" and agrarian ideology - for the rhetoric and resentments which developed were as much a function of regional parochialisms, divergent political histories and immigration patterns as the relativity of belief systems. Beyond this, the single economic interest of the prairie grain grower, the subordinate status of the West, and a parliamentary system of government which prevented the emergence of an agrarian bloc as a significant force in national politics, all conspired to precipitate the farmers' eventual political demise. Yet within the prairie provinces themselves, farmer-controlled governments exerted considerable influence which the farm lobby continued with the appearance of broadly-based coalition parties in Saskatchewan and Alberta after 1935. In order to assess and measure this influence effectively, however, the analysis of the formative years of the agrarian response to industrialization from 1900 remains indispensable.

As a means of differentiating among various types of social movements, the frame of reference employed by Neil Smelser with its unique set of determinants proved useful for the task. These determinants - strain, conduciveness, precipitating events, generalized belief, mobilization for action, and social control - may be utilized as heuristic devices to sensitize the observer to the subtleties of agrarian behaviour. Through the emergence of agrarian economic, educational, and cooperative organizations to the demands for direct legislation and political action, farmers' efforts were concentrated on rendering the values and goals of rural agricultural society achievable by creating new rules, procedures, and norms. As such, the farmers' impact on the economic and political history of the West may be viewed, not as an effort to radically transform Canadian society, but to ensure that agriculture would remain viable in a highly heterogeneous economy.

In utilizing historical data and certain insights drawn from the discipline of sociology, it is possible to provide the practitioner and the student of Canadian agrarian history with a more complete understanding and appreciation of the contours of agrarian disaffection. This exercise in turn provides important insights into the foundation of urban-rural and farmer-government relationships, as well as of the association between agriculture and such socio-economic groups as organized labour. The evolution of agrarian protest and the formation of group action and ideology, furthermore, are significant examples of how the forces of change may operate to accelerate the dual processes of adaptation and disaffection, and, ultimately, influence the institutional and social development of society as a whole.

abstract: Doctor of Philosophy (PhD)


title: The Circadian Rhythms of Core Body Temperature, Serum Cortisol and Serum Melatonin: Patterns of Disruption in Chronic Insomnia of Chronobiologic Origin

contributor:
Cleghorn, John M.
Medical Sciences

subject:
Medicine and Health Sciences
Medicine and Health Sciences

abstract:
After specific causes of chronic insomnia have been ruled out (e.g., noctural myoclonus, drug abuse), there remain in a substantial number of patients who have been inexplicably sleepless and fatigued for many years. We wished to learn whether the chronicity of insomnia in these patients was associated with phase-shifts in circadian rhythm, a disorder of internal timekeeping. We identified three types in a pilot study: 1) phase-delay, b) phase-advance, and c) an arrhythmic group.

Delayed sleep-phase insomnia (DSPI) has been well described. It is characterized by an intractably late sleep-onset and awakening time, a consistent sleep time-frame, and an essentially normal sleep EEG.

Advance sleep-phase insomnia (ASPI) is a much rarer phenomenon, with few reported cases. Sleepiness becomes overpowering in the late afternoon or early evening, followed by a very short sleep onset latency and exceedingly early awakening time. The EEG is essentially normal.

Amplitude disorders and arrythmia are even more rare under normal environmental conditions. They have been described but not carefully examined. We identified two patients in the pilot study who displayed a complete arrythmia of their core temperature cycle. Their sleep was marked by variable onset latencies, and severe difficulties with sleep maintenance. Sleep-time averaged less than two hours per night, and was associated with a substantial reduction in the slow-wave sleep.

Though these patterns sound easy to recognize, they are often obscured in patient reports. For example, social schedules requiring early rising for work in spite of phase-delay or explanations that patients develop to better account for their predicament may disguise true patterns. We tried to detect the more intractable features in patient histories and reported patterns of sleep and to predict which type of phase disturbance each might have.

The physiological aspects of the circadian phase disturbance was examined using the sleep-wake cycle (14 x 24 hours), core body temperature (5 x 24 hours), serum cortisol (1 x 24 hours) and serum melatonin (1 x 24 hours) as circadian parameters. Monitoring was carried-out on three patient groups identified in the Sleep Disorders Clinic as being : 1) phase-delayed, 2) phase advanced, or 3) arrythmic.

The phase-delay group showed a significant delay in the acrophase of core temperature rhythm, but not serum cortisol. The phase advance group showed a significant advance in the acrophase of both rhythm parameters. The arrhythmic group displayed a highly variable core temperature acrophase but intact 24 hour waveforms. Serum cortisol had no discernable rhythmic component in this group.

The circadian rhythm of serum melatonin showed a significant acrophase delay for all patient groups. This was an unexpected result, as the phase control of melatonin secretion is thought to originate from oscillators providing phase information to the other parameters meausred in this study.

Also important was the finding that there was no significant difference in the amplitude or period length for all three circadian rhythm parameters. Thus, "phase-disorders" seen in the present study possibly represent a defect in carcadian rhythm timing but not in the generation of rhythms themselves. However, in patient Group 3 the substantial increased point to point random variation in core temperature and the arrhythmic nature of the serum cortisol secretion could imply involvement of rhythm timing and/or generation.

Since these phase disorders were associated with a consistent and unidirectional phase change in the circadian pattern of melatonin secretion, it is hypothesized that the pathology in these patients may lie at the level of the suprachiasmatic nucleus. Hyposensitivity to light could interfere with melatonin "offset" signals, while allowing other pacemakers to move toward their endogenous cycling frequencies. Thus, phase delayed, or advanced, or a more drastic rhythm anomaly might ensue.

This study also indicates that it may be possible to identify each of the three types of rhythm disturbance on the basis of clinical features that can be obtained by interview. The most important aspects appear to be: 1) chronicity of symptoms, 2) consistency of symptoms, 3) pattern of symptoms, 4) psychiatric and medical histories, and 5) recnet drug histories. In addition, polysomnographic studies are required to exclude specific disorders such as nocturnal myoclonus.

Exogenous melatonin administration was carried out on this patient sample. A double-blind, placebo-controlled, 14-day trial showed a significant improvement of both total sleep time and day-time alertness with a 75mg oral does of melatonin as compared to placebo. This is the first study to demonstrate significant clinical soporiphic effects of exogenous melatonin in chronic insomniac patients.

abstract: Doctor of Philosophy (PhD)


title: Dynamic and Seismic Characteristics of Cable-Stayed Bridges

contributor:
Wilson, John C.
Civil Engineering

subject:
Civil Engineering
Civil Engineering

abstract:
Cable-stayed bridges have been gaining popularity in the last few decades as a viable, efficient, economical and aesthetically appealing design for spanning medium to long crossings. The construction of these bridges in seismic regions has created a need to more fully understand their dynamic behaviour and seismic response.

The objectives of this research work are to: (1) define a dynamic modal analysis procedure suitable for cable-stayed bridges, and (2) use the developed procedure to study seismic response characteristics of cable-stayed bridges.

The research program was divided into four main stages: (1) development of analytic models for estimating frequencies of two of the main structural systems of cable-stayed bridges (i.e. deck and tower); (2) a 3-D model of Quincy Bayview Bridge was used as a prototype structure to study the modal characteristics of cable-stayed bridges and investigate the effect of major geometric parameters on the modal characteristics of cable-stayed bridges; (3) eigenvectors and load dependent Ritz vectors were examined to compare their appropriateness as bases for modal transformation of the equation of motion of cable-stayed bridges. A seismic response study was conducted of the Quincy Bayview Bridge in each vector basis to judge which is more appropriate for dynamic and seismic analysis of cable-stayed bridges. Frequency cut-off criteria were proposed that would ensure the inclusion of all important modes in a dynamic analysis; and (4) the proposed criteria were applied in a seismic response study that used a 3-D finite element model of the Quincy Bayview Bridge. The study investigated the effect of frequency content of ground motion on the seismic response of cable-stayed bridges with different deck supports.

The results of the study showed that modal characteristics of cable-stayed bridges are most affected by the cable arrangement, the tower shapes, and deck supports. Almost the same number of eigenvectors or Ritz vectors are required to ensure the inclusion of all important modes in a modal analysis. To ensure the inclusion of all important modes, it is proposed to calculate an upper limit frequency using the developed analytic models, generate modal vectors up to the set limit and then check the effective modal mass of these vectors to meet a pre-set percentage of the total mass. The study showed that seismic response of a cable-stayed bridge is strongly dependent upon the deck support condition, and the frequency content of input motion. It also showed that towers are less sensitive to changes in frequency content of the ground motion than the deck.

abstract: Doctor of Philosophy (PhD)


title: Simulation of Conduit Network Development on Bedding Planes

contributor:
Ford, D.C.
Geography

subject: Geography Geography

abstract:
The development of conduit networks on bedding plane surfaces has been simulated in a series of laboratory analogue experiments. Two types of hardware models were used to study the influence of various hydraulic and structural boundary conditions on the pattern of these networks.

Network pattern was found to be directly related to the pattern of fluid flow in the bedding plane, as determined by the configuration of input and output areas.

Bedding plane inclination did not directly affect network pattern. However, the relationship between stratal dip and the accumulation of sediment within the network may indirectly affect network pattern.

The shape of conduits in cross section was found to depend on their mode of origin. Discrete tubes maintained a circular cross section throughout their growth. However, anastomotic bands of tubes tended to develop into a single tube of elliptical cross section.

abstract: Master of Science (MS)


title: Parallel Distributed Computation of Power System Transient Stability Problems

contributor:
Alden, R.T.H.
Electrical Engineering

abstract:
Transient stability analysis, a necessary tool for planning and operating electrical power systems, is most time consuming to use because of its massive computational burden. Therefore, the solution of this problem on multiprocessor systems has attracted a lot of attention and holds the promise of eventual real-time dynamic security assessment.

In this thesis, methods to speedup the computation of power systems transient stability simulations using parallel distributed processing are examined. The approach of the thesis is twofold. Firstly, practical implementation must consider the use of current widely available networked computers in the industry. Secondly, the parallel distributed algorithms to be developed in this thesis must as far as possible retain algorithmic advances that have been made on its serial counterpart because of their many advantages.

Serial transient stability algorithms are studied and all major algorithmic advances are investigated and implemented. State-of-the-art parallel transient stability calculations are reviewed and for each algorithm the parallelism that has been exploited is identified. The choice of parallel processing hardware and software is of major concern to power utilities. These issues are discussed and justifications for using networked workstation are given.

The two approaches mentioned above lead naturally to coarse-grained partitioning of the transient stability problem. A slow coherency network partitioning that divides the network into several coherent areas along naturally occurring weak links is developed in this thesis. Following network partitioning, computational tasks can be distributed to several computers and then executed simultaneously. Solution of large, sparse algebraic linear systems is required in most power system analysis. In transient stability analysis, the solution of the linear transmission network is the major obstacle to real-time simulations. In this thesis, both direct and iterative methods for solving blocked linear algebraic systems associated with the power network are developed and implemented on a cluster of workstations. RPC (Remote Procedure Calls) techniques together with multiprocessing primitives are used for client-server communications. These aspects and techniques are fully discussed in this thesis.

Based on the network partitioning and solution methods developed, a transient stability algorithm is parallelized. The process of parallelization is carefully demonstrated. Both shared memory multiprocessor and RPC based--distributed memory--versions are developed. The corresponding speedup due to these methods are analyzed and discussed. It is shown that techniques developed in this thesis can be applied to production grade transient stability programs.

abstract: Doctor of Philosophy (PhD)


title: Pavlovian Conditioning and Tolerance to Cholecystokinni-8 and Naloxone-Induced Meal Suppression

contributor:
Siegel, S.
Psychology

subject: Psychology Psychology

abstract:
Administration of the gut peptide, cholecystokinin (CCK), results in a suppression of meal size. The opiate-antagonist, naloxone (Nx), also suppresses feeding. With few exceptions, studies of the effect of either CCK or Nx have not examined the effects of repeated administrations, and thus there are little data concerning tolerance.

Experiment 1 was designed to investigate the effect of CCK following repeated daily injections. It was found that after several days of CCK, it no longer suppressed feeding; that is, tolerance to CCK had occurred. The demonstration of contingent tolerance in Experiment 2 confirms the results of Experiment 1 as well as the results obtained from Bednarz, Asin and Nadzan (1992), who showed that tolerance to CCK was dependent upon CCK and food being given at the same time. The results from Experiment 2 also demonstrate the importance of learning principles in mediating this tolerance; following a saline test, an over-consumption of sucrose was evident.

Experiments 3 and 4 extend these findings by demonstrating further, the importance of learning principles. Experiment 3 demonstrated that tolerance is only displayed when the drug is administered in the context of usual drug-predictive cues. Experiment 4, a latent inhibition experiment, assessed the prediction that pre-exposure to a conditioned stimulus (CS) should slow tolerance development. By demonstrating latent inhibition, this confirms the importance of learning principles.

Experiments 5 through 8 were designed to investigate tolerance to Nx. The importance of learning principles in mediating this tolerance was also assessed. Experiment 5 demonstrated that a dose of 1 mg/kg of Nx significantly decreased sucrose consumption. This suppression of intake diminishes, when animals were injected daily, as shown in Experiment 6. Experiment 7 showed that, like CCK, a contingency between food and Nx is necessary for tolerance to be demonstrated. The importance of learning principles was clearly shown in Experiment 8, where it was demonstrated that tolerance is only displayed when the drug is administered in the context of usual drug-predictive cues.

Much evidence suggests that CCK acts as an opiate-antagonist in the modulation of pain, and that Nx and CCK affect feeding in a similar manner. Experiments 1 through 8 show that tolerance to the meal-suppressive effect occurs when either CCK or Nx is given repeatedly. In a final experiment (Experiment 9), cross-tolerance to CCK- and Nx-induced meal suppression was assessed. Experiment 9 demonstrated that the tolerance that develops to CCK is symmetrical with respect to Nx. This result adds further support to the claim that CCK and Nx affect feeding behaviour in a similar manner. The mechanism(s) of action responsible for tolerance remains to be elucidated.

abstract: Doctor of Philosophy (PhD)


title: Cyclic Deformation of Low-Carbon Iron

contributor:
Embury, J. D.
Metallurgy and Materials Science

abstract:
The mechanical behaviour and the microstructural changes preceeding fatigue fracture have been investigated in ferrous systems subjected to controlled cyclic straining. Attention has been focussed on three basic aspects of the fatigue process:

(1) The Bauschinger Effect and the Polarisation of Plastic Flow in Single- and Two-Phase Iron-Based Alloys: the investigation involved the study of the influence of dislocation distribution on the magnitude of the Bauschinger effect, and the study of the Bauschinger effect in two-phase materials as a function of both forward strain and volume fraction of particles. The results are interpreted in terms of some of the currently available theories for the deformation in plastically inhomogeneous materials.

(2) Fatigue Softening in Single-Phase Low-Carbon Iron: the investigation involved the study of the microstructural changes occurring in prestrained specimens during cyclic softening, and the influence of initial dislocation arrangement on the rate and extent of fatigue softening. Simple models were developed to rationalize the kinetics of fatigue softening.

(3) Instability of Plastic Flow in Quenched-Aged Armco Iron: the investigation involved the study of the influence of various particle dispersions on the stability of plastic flow in fatigue, and the detailed microstructural features developing in fatigue which lead to the localization of plastic flow and onset of fatigue cracks. The problem of instability has been rationalized, macroscopically, in terms of the mechanical equation of state, and microscopically, in terms of the detailed structure of the localized regions.

Structural changes were monitored by Transmission Electron Microscopy and ancillary techniques in order to provide a detailed characterisation of the fatigue state.

abstract: Doctor of Philosophy (PhD)


title: Ontario Precipitation Chemistry and Heavy Metal Speciation

contributor:
Kramer, James R.
Geochemistry

subject: Geochemistry Geochemistry

abstract: Gross Ontario rain and snow chemistry and heavy metal speciation was determined on samples collected from a precipitation sampling network established in Hamilton and Northern Ontario. Relative to surface waters, precipitation is normally a low conductivity (mean value = 34 μmho/ cm (25°)), low pH (4.3) system with elevated heavy metal (10 - 100 μg/l) and nutrient (50 - 100 μg/l P; 400 - 2000 μg/l N) concentrations. Anodic stripping voltammetry (ASV) was employed to determine "soluble" heavy metal speciation. ASV peak potential shifts and current measurements were used as criteria in making this determination. Unusual anodically shifted Cu peaks common to many precipitation samples suggested a Cu-colloid association. Duplication of polarographic behaviour observed for natural precipitation samples was obtained with synthetically prepared Fe-Mn colloids. In terms of "soluble" Cu speciation, Northern Ontario could be divided into two distinct regions; near Sudbury rain and snow contained aquo-Cu⁺⁺ ion at elevated concentrations, while in the remainder of the province, precipitation contained colloidally associated copper. Zn, Cd, and Pb were generally present as the aquo-species. Rain-out of colloidally associated copper into the higher ionic strength environment of lakes will probably result in metal desorption and colloid flocculation. Copper would then be available as a biologically toxic species.

abstract: Doctor of Philosophy (PhD)