title: Effect of the Processing Route on the Localized Corrosion Susceptibility of Al Alloy AA7050 in Saline Solutions

contributor:
Kish, Joseph R.
Materials Science and Engineering

subject: Corrosion Corrosion AA7050 Aluminum CDS Casting Wrought

abstract:
Experiments were conducted to characterize and compare the localized corrosion susceptibility of the granular microstructure of aluminum (Al) alloy AA7050 in the peak aged T6 condition cast by the novel controlled diffusion solidification (CDS) process against the conventional wrought plate counterpart. CDS is a casting technique that involves mixing two precursor melts at specific temperatures and compositions before solidification. This process avoids the problem of hot tearing by causing copious nucleation of the solid phase within the melt before solidification, reducing the amount of solute segregation and, thus dendritic growth creating a consistently equiaxed microstructure.
The effect of the CDS processing route on its relative localized corrosion susceptibility was elucidated by making links between the microstructure heterogeneities and the localized corrosion susceptibility as evaluated in aqueous saline solutions. Microstructures were characterized and compared with the use of the following techniques:
	1. Scanning electron microscopy (SEM) to characterize grain size, shape and distribution.
	2. Electron backscattered diffraction (EBSD) in SEM mode to characterize grain misorientation and the associated distribution.
	3. Auger electron spectroscopy (AES) to characterize the composition of the grain boundary region including the precipitate free zone (PFZ) and the grain boundary precipitates.
	4. Atom probe tomography (APT) to define the size, distribution, and composition of the strengthening matrix precipitates along with the grain boundary region (PFZ and grain boundary precipitates).
Electrochemical experiments were conducted to characterize and compare the localized corrosion susceptibility of the two materials (CDS and conventional wrought) exhibited in aqueous saline solutions. Specific techniques include the following:
	i. Potentiodynamic polarization measurements of mechanically-abraded surfaces to determine the corrosion potential (Ecorr) and breakdown potential (Eb).
	ii. Potentiostatic anodic polarization of mechanically-abraded surfaces to observe the mode and extent of localized corrosion.
	iii. Open-circuit potential (OCP) measurements of fracture surfaces to determine the OCP of a surface with a significantly higher grain boundary area fraction relative to the bulk material.
	iv. Cyclic acidified salt (sodium chloride (NaCl)) fog testing (ASTM-G85-Annex 2) to validate the relative localized corrosion susceptibility under more realistic atmospheric corrosion exposure conductions.
The CDS casting technique resulted in an entirely equiaxed microstructure. The microstructure was isotropic with an average grain size of 25±1 µm and an aspect ratio of around 1. This grain structure was in stark contrast with the wrought material, which exhibited a granular structure elongated along the rolling direction. The wrought material had a cord length of 56±3.2 µm in the rolling direction, 51±3 µm in the traverse direction and 13.3±1.6 µm in the short traverse direction. The wrought material had an aspect ratio of around 4 in the longitudinal plane (LS), 2.6 in the short transverse plane (ST) and 1.2 in the rolling plane (LT). AES and APT revealed that the CDS material had a higher amount of copper (Cu) segregation into the grain boundary precipitates. Electrochemical testing showed that the wrought material had a Eb  of −750 ± 3 mV while the CDS had a higher Eb  of −697 ± 4 mV. The Cu segregation into the grain boundary precipitates yielded more electrochemically active grain boundaries, as revealed by the OCP measurements. Despite this fact, localized corrosion of the CDS material initiated as pitting and propagated as a mixed mode involving intergranular corrosion (IGC) and pitting. The localized corrosion mode exhibited by the wrought material was purely IGC: both in initiation and propagation. The difference in corrosion mode was found to be due to the differences in the size of the Fe-based IMPs and the distribution of the Cu secondary phase precipitates: The CDS had large Fe IMP trapped at the grain boundary triple points and clustering of Cu secondary phase precipitates. Conversely, the wrought material had finely dispersed Fe IMP of significantly smaller size than those found in the CDS, and its Cu secondary phase precipitates are evenly distributed along the grain boundaries. These differences in precipitate distribution enhanced susceptibility for pitting in the CDS and reduced the driving force for IGC. The propagation of localized corrosion was markedly reduced in the CDS material: about half of that exhibited by the wrought material (under identical exposure conditions). Cyclic acidified salt fog testing revealed industry acceptable levels of localized corrosion susceptibility in-line with the benchmark alloys that are currently used in automotive applications.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Functional Analysis of the Role of TRF1 Phosphorylation on Threonine 271 and Threonine 371 in Telomere Maintenance

title: Functional Analysis of TRF1 Phosphorylation in Telomere Maintenance

contributor:
Zhu, Xu-Dong
Biology

subject:
Telomere
Cancer
TRF1
Biology
DNA repair
ALT
PML bodies
Cdk

abstract: TRF1, telomeric-repeat binding factor 1, is a component of the six-subunit protein complex, referred to as shelterin, which is essential for not only regulating telomere length maintenance but also protecting mammalian telomeres from being recognized as damaged DNA. TRF1 acts as a negative mediator of telomerase-dependent telomere elongation in telomerase-expressing cells, whereas it promotes alternative lengthening of telomeres (ALT) activity by regulating ALT features including the production of extrachromosomal telomere-repeat (ECTR) DNA such as C-circles, and ALT-associated promyelocytic leukemia bodies, or APBs. The activity of TRF1 is tightly regulated by post-translational modification such as phosphorylation. This thesis sets out to investigate the function of TRF1 phosphorylation on threonine-271 (T271) and threonine-371 in telomere maintenance. The results presented in this thesis demonstrate that TRF1 phosphorylation on T271 positively regulates the association of TRF1 to telomeric DNA in telomerase expressing cells. In ALT cells, TRF1 phosphorylation on both T271 and T371 is shown to be important for the formation of APBs. Furthermore, the work presented here suggests that transcription-associated DNA damage mediates the association of phosphorylated (pT371)TRF1 with APBs.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: TRF1, telomeric-repeat binding factor 1, is a component of the shelterin complex, which is essential for regulating telomere length maintenance and protecting mammalian telomeres from being recognized as damaged DNA. TRF1 acts as a negative mediator of telomerase-dependent telomere elongation in telomerase-expressing cells, whereas it promotes alternative lengthening of telomeres. The activity of TRF1 is tightly regulated by phosphorylation. This thesis sets out to investigate the function of TRF1 phosphorylation on threonine-271 and threonine-371 in telomere maintenance. Understanding how post-translational modifications on TRF1 may be linked to telomere homeostasis will be crucial for our understanding in cancer cell biology.


title: SYNTHESES AND STRUCTURES OF RHENIUM(VII) AND MANGANESE(VII) OXIDE FLUORIDES, MANGANESE(V, IV) FLUORIDES, AND THE FIRST OXIDE OF XENON(II)

contributor:
Schrobilgen, Gary J.
Chemistry and Chemical Biology

subject: rhenium trioxide fluoride, rhenium(VII) trioxide cation, rhenium(VII) trioxide difluoride anion, rhenium(VII) trioxide trifluoride anion, first xenon(II) oxide cation, first manganese(V) fluorides, new rhenium(VII) oxide fluoride

abstract:
This Thesis extends the chemistry of group VII transition metal oxide fluorides, namely ReO3F and MnO3F. The fundamental chemistry of ReO3F has been significantly extended with the development of its high-yield and high-purity synthesis. This has been achieved by solvolysis of Re2O7 in anhydrous HF (aHF) followed by reaction of the water formed with dissolved F2 at room temperature. The improved synthesis has allowed the Lewis acid and fluoride-ion donor-acceptor properties of ReO3F to be further investigated. The Lewis acid-base complex, (HF)2ReO3F·HF, was obtained by dissolution of ReO3F in aHF at room temperature and was characterized by vibrational spectroscopy with aid of quantum-chemical calculations and single-crystal X-ray diffraction at −173 °C. The HF molecules are F-coordinated to rhenium, representing the only known example of an HF complex with rhenium. The study of the fluoride-ion acceptor properties of ReO3F resulted in the syntheses and characterization of the [{ReO3(μ-F)}3(μ3-O)]2−, [ReO3F3]2−, and [ReO3F2]− anions. The [{ReO3(μ-F)}3(μ3-O)]2− anion was obtained as the [N(CH3)4]+ salt by the reaction of stoichiometric amounts of ReO3F and [N(CH3)4]F in CH3CN solvent. The anion was structurally characterized in CH3CN solution by 1D and 2D 19F NMR spectroscopy and in the solid state by Raman spectroscopy and a single-crystal X-ray structure determination of [N(CH3)4]2[{ReO3(μ-F)}3(μ3-O)]·CH3CN. The structure of the [{ReO3(μ-F)}3(μ3-O)]2– anion consists of three ReO3F units linked to each other through dicoordinate bridging fluorine atoms (F) and a central tricoordinate bridging oxygen atom (O3). Calculated vibrational frequencies and Raman intensities of the [{MO3(μ-F)}3(μ3-O)]2− (C3v) and [{MO3(μ-F)}3(μ3-F)]− (C3v) anions (M = Re, Tc) have been used to assign the Raman spectrum of [N(CH3)4]2[{ReO3(μ-F)}3(μ3-O)]·CH3CN. The fac-[ReO3F3]2− and [ReO3F2]− anions have been synthesized by the reactions of ReO3F with CsF and KF in aHF, and by reaction of ReO3F with NOF. Additionally, the [ReO3F2]− anion has been synthesized by the reaction of ReO3F with [NH4]F in aHF. Both anions were characterized by Raman spectroscopy in the solid state and single-crystal X-ray diffraction. The calculated vibrational frequencies of the fac-[ReO3F3]2− (C3v) and [(µ-F)4(ReO3F)4]4− (C4v) anions were used to assign the Raman spectra of fac-[ReO3F3]2− and [ReO3F2]−, respectively. The rhenium atoms in the open-chain, fluorine-bridged [ReO3F2]− anion and the monomeric fac-[ReO3F3]2− anion are six-coordinate with a facial arrangement of the oxygen ligands. The fluoride-ion donor properties were established by the reactions of ReO3F with excess AsF5 and SbF5/SO2ClF. Both reactions resulted in the formation of white friable solids, µ-O(ReO2F)(AsF5)∙2AsF5 and [ReO3][Sb3F16]. The [ReO3][Sb3F16] salt is stable at room temperature and decomposes to [ReO2F2][SbF5], when maintained at 45 oC under dynamic vacuum. The µ-O(ReO2F)(AsF5)∙2AsF5, however, slowly decomposes at 0 oC to ReO3F and AsF5. Both products were characterized by Raman spectroscopy in the solid state with aid of quantum-chemical calculations. The vibrational analyses revealed that the geometry of [ReO3][Sb3F16] is consistent with a trigonal pyramidal arrangement of oxygen atoms around rhenium, whereas in µ-O(ReO2F)(AsF5)∙2AsF5, ReO3F interacts with one of the AsF5 molecules through an O-bridge, which represents the first example of such type of bonding. The reactions of µ-O(ReO2F)(AsF5)∙2AsF5 and [ReO3][Sb3F16] with CH3CN resulted in the formation of the white salts, [O3Re(NCCH3)3][PnF6] (Pn = As, Sb), which were characterized by Raman spectroscopy.
The reactivity of ReO3F has been extended to the synthesis of a new Re(VII) oxide fluoride, (μ-F)4{[μ-O(ReO2F)2](ReO2F2)2}, which was synthesized by the reaction of 1:3 molar ratio of ReO3F and ReO2F3. The compound, (μ-F)4{[μ-O(ReO2F)2](ReO2F2)2}, a rare example of an O-bridged rhenium oxide fluoride, has been characterized by single-crystal X-ray diffraction and solid-state Raman spectroscopy. The vibrational assignments of (μ-F)4{[μ-O(ReO2F)2](ReO2F2)2} were confirmed by 18O-enrichment and quantum-chemical calculations.
The improved synthesis of ReO3F has also led to the synthesis and characterization of the novel [XeOXeOXe]2+ cation as its [μ-F(ReO2F3)2]− salt by the low-temperature reaction of ReO3F and XeF2 in aHF. The [XeOXeOXe]2+ cation provides an unprecedented example of a xenon(II) oxide and a noble-gas oxocation as well as a rare example of a noble-gas dication. The crystal structure of [XeOXeOXe][µ-F(ReO2F3)2]2 consists of a planar, zigzag-shaped [XeOXeOXe]2+ cation (C2h symmetry) that is fluorine bridged through its terminal xenon atoms to two [µ-F(ReO2F3)2]– anions. The Raman spectra of the natural abundance and 18O-enriched [XeOXeOXe]2+ salts are consistent with a centrosymmetric (C2h) cation geometry. Quantum-chemical calculations were used to aid in the vibrational assignments of [Xe16/18OXe16/18OXe][µ-F(Re16/18O2F3)2]2 and to assess the bonding in [XeOXeOXe]2+ by NBO, QTAIM, ELF, and MEPS analyses. Ion pair interactions occur through Re–Fμ---Xe bridges, which are predominantly electrostatic in nature and result from polarization of the Fμ-atom electron densities by the exposed core charges of the terminal xenon atoms. Each xenon(II) atom is surrounded by a torus of xenon valence electron density comprised of the three valence electron lone pairs. The positive regions of the terminal xenon atoms and associated fluorine bridge bonds correspond to the positive σ-holes and donor interactions that are associated with “halogen bonding”.
	The reactions of MnO3F with noble-gas fluorides, KrF2 and XeF6, have been studied as the possible synthetic routes to MnOF5 and MnO2F3. The reaction of MnO3F with KrF2 yielded a red solid, which was isolated as a crystalline solid at room temperature and its crystal structure was assigned to manganese(V) fluoride, MnF5. The crystal structure of polymeric MnF5 consists of MnF6-octahedra which are trans-coordinated through fluorine bridges. The geometrical parameters of MnF5 could not be reliably determined due to unresolved twinning issues. The reaction of MnO3F with KrF2 in the presence of K[HF2] yielded a red-orange solid mixture of K[MnF6] (soluble in HF) and MnF3 (insoluble in HF). The HF solution of the solid mixture was characterized by 19F NMR spectroscopy and the resonance observed in the 19F NMR spectrum was preliminary assigned to [MnF6]  by comparison with the chemical shift observed in the 19F NMR spectrum of MnO3F. Additionally, MnO3F was characterized by 19F−55Mn COSY NMR and 55Mn NMR spectroscopies, the latter provided the first 1J(19F−55Mn) coupling constant. The K[MnF6] salt was also characterized by single-crystal X-ray diffraction. The resulting octahedral geometry is imposed by symmetry, therefore, the anticipated Jahn-Teller distortion, which would result in D4h symmetry for the [MnF6]  anion, could not be observed. The reaction of MnO3F with XeF6 resulted in the isolation of [Xe2F11]2[MnF6] and [XeF5]2[MnF6]. Both salts were characterized by low-temperature single-crystal X-ray diffraction. The [Xe2F11]2[MnF6] salt was additionally characterized by low-temperature Raman spectroscopy with the aid of quantum-chemical calculations, whereas the assignment of the known Raman spectrum of [XeF5]2[MnF6] has been improved in the present work.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Governing Dogs: An Autoethnographic Tale of Redefining 'Service Dog' in Canada

contributor:
Gillett, James
Gabel, Chelsea
Health and Aging

subject:
Service Dog
Accomodation
Disability
Legislation
Autoethnography
Critical Disability Theory

abstract:
Service dogs are becoming an integral part of our society. Consequently, there is a need for research that explores how Canada should proceed with the development and implementation of appropriate laws and policies that will ensure the proper use and equal integration of service dogs. Before this can take place, the terminology used within the field must be clarified, as society continues to move toward a more expanded definition of service dog, and public access challenges continue to impact the lives of persons with disabilities.
	The goal of this autoethnographical research study was to determine what service dog handlers, particularly ‘owner-trainers,’ feel constitutes a ‘service dog’ in Canada. When researchers conduct investigations on topics related to the lives of persons with disabilities, their research typically takes the form of disabled individuals being studied and not being directly involved within the research. Therefore, this project sought to directly involve persons with disabilities, while also attempting to avoid the possibility of censorship or silence. Through the use of statements from social media, this project captured the lived experiences without worrying about participants changing them to fit within society’s expectations. Society is not structured to be accessible for all, so when ‘accommodations’ are made, it is ‘expected’ that persons with disabilities will show gratitude and not voice their true feelings. Through the use of autoethnography, I shared my experiences, as a service dog raiser, trainer and handler, and provided a glimpse into the lives of other service dog handlers as they participate within their communities. In doing this, I hope the findings of my project will offer an important perspective to the discussion surrounding what constitutes a ‘service dog’ in Canada.

abstract: Thesis

abstract: Master of Arts (MA)


title: Examination of Prostate Cancer Stem-like Cell Associated Factors for their Contribution Towards the Development of Castration Resistant Prostate Cancer

contributor:
Tang, Damu
Medical Sciences

abstract: Although early detection and treatment of prostate cancer (PC) shows some benefit, advanced PCs that progress despite androgen deprivation become castration resistant (CRPC). This stage becomes largely incurable as CRPCs are intimately associated with metastasis, the predominant cause of PC-related fatalities. Increasing evidence reveals the role of prostate cancer stem cells (PCSCs) in mediating PC progression. Taking advantage of our putative PCSC population derived from DU145 cells, we have examined a number of candidates for their contribution to PCSC-related PC progression and CRPC development. PKM2 plays a major role in cancer cell metabolism by inducing a shift towards aerobic glycolysis (the Warburg effect) to convert metabolic intermediates into cellular building blocks. PKM2 has also been demonstrated in non-metabolic oncogenic functions. Here we reveal an association with higher Gleason PC tissues, and distinct post-translational modifications in our PCSCs. MUC1 is a well-known tumour associated antigen with widespread oncogenic effect. We demonstrate increased MUC1 expression in our PCSCs, upregulation following docetaxel treatment in vivo, and a unique MUC1 network gene signature which may be used to predict CRPC. FAM84B is a novel protein in cancer, and we demonstrate higher expression of FAM84B in our PCSCs and in two animal models of CRPC. Using gene expression databases, both MUC1 and FAM84B were revealed to associate with metastasis and CRPC. Lastly, CSCs arewidely regarded as being chemoresistant, and we have revealed elevated expression of a drug transporter ABCC2 in our PCSCs and in higher Gleason PC tissues. We also present preliminary evidence that ABCC2 may contribute to docetaxel resistance in DU145 sphere-derived subcutaneous xenografts. Co-expression of these four factors in our putative DU145 PCSCs and their widespread impact on diverse mechanisms of cell proliferation and survival underscores the importance of PCSCs in promoting advanced prostate cancer.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: DEVELOPMENT OF A GENETIC ALGORITHM APPROACH TO CALIBRATE THE EVPSC MODEL

contributor:
Wu, P.D.
Mechanical Engineering

subject:
EVPSC
Genetic Algorithm

abstract:
Magnesium is known as one of the lowest density metals. With the increasing importance of fuel economy and the need to reduce weight, magnesium has proven to be a very important structural material used in transportation industry. However, the use of magnesium alloys have been limited by its tendency to corrode, creep at high temperature, and higher cost compare to aluminium alloys and steels.
Polycrystal plasticity models such as VPSC and EVPSC were used to study deformation mechanisms of magnesium alloys. However, current polycrystal plasticity models with slip and twinning involve a large number of material parameters, which may not be uniquely determined. Furthermore, determining material parameters using traditional trial-and-error approach is very time consuming. Therefore, a genetic algorithm approach is developed in this thesis to optimize these material parameters.
The genetic algorithm approach is evaluated by studying large strain behavior of magnesium alloys under different deformation processes. The material parameters for those models are determined by material numerical simulations based on the polycrystal model to the corresponding experimental data. Then the material parameters are used to make prediction of other deformation behaviours (stress strain curves, R values, texture evolution and lattice strain), and the performance is judged by how well the prediction match the actual experimental data. The results show that the genetic algorithm approach works well on determining parameters, it can get reliable results within a relatively short period of time.

abstract: Thesis

abstract: Master of Applied Science (MASc)


contributor:
Neilson, Thomas
Biochemistry

abstract: Title: Chemical Synthesis of Guanosine Oligoribonucleotides: The Synthesis of N^2-Benzoyl-2'-O-tetrahydropyranylguanosine and N^2-benzoyl-2'-O-tetrahydropyranyl-5'-O-triphenylmethoxyacetylguanosine, Author: Edward V. Wastrodowski, Location: Thode

abstract:
Synthesis of oligoribonucleotides of defined sequence and length
corresponding to regions within biologically active RNA species is an
attractive proposition. The specific objective is the synthesis of
oligoribonucleotides corresponding to the amino acyl synthetase acceptor
stem region of yeast tRNA^ala. This sequence contains many guanosine
residues but guanosine derivatives necessary for incorporation into a
general synthesis were not at hand. The synthesis of N^2-benzoyl-2'-O-
tetrahydropyranylguanosine (VI) and N^2-benzoyl-2'-0-tetrahydropyranyl-
5'-0-triphenylmethoxyacetylguanosine (VIII) are carried out. Their
utilization in the synthesis of guanylyl(3'-5')guanosine (GpG) is
described. These precursors, VI and VIII, can now participate in a
fragment coupling synthesis of the duplex corresponding to the acceptor
stem region of yeast tRNA^ala.

abstract: Thesis

abstract: Master of Science (MS)


title: Theoretical studies of stripe states in underdoped cuprate superconductors

contributor:
Kallin, Catherine
Physics and Astronomy

subject:
cuprate superconductors
stripe

abstract: In this thesis, we study stripe states in underdoped cuprate superconductors using the Bogoliubov-de Gennes (BdG) method with appropriate models. In non-self-consistent calculations, the nature of stripe states with coexisting unidirectional Pair Density Wave (PDW), Charge Density Wave (CDW), and Spin Density Wave(SDW) order is studied, and it was found that among these coexisting stripe orders, the SDW order plays a key role in reconstructing the Fermi Surface (FS), and the magnitude of SDW order needs to be relatively small in order for Fermi arcs to be realized, while strong SDW order necessarily leads to completely gapped spectra. In self-consistent calculations, we mapped out parameter regions where stripe SC states can be stabilized, which are in qualitative agreement with the generic phase diagram of cuprate superconductors. In addition, self-consistent PDW solutions with small SDW order are stabilized in some parameter region, forming small FS pockets in antinodal regions. This parameter region is a promising one to explore in future work, where self-consistent BdG calculation is to be carried out with a magnetic field in order to study the effect of magnetic field on the stability of stripes along with the possible quantum oscillations.

abstract: Thesis

abstract: Master of Science (MSc)


title: The Decomposition of Matrices

contributor:
Csima, J.
Mathematics

abstract: Title: The Decomposition of Matrices, Author: Wilfred A. Ward, Location: Thode

abstract: This thesis deals with algorithms which, for a given square matrix A of order n, construct permutation matrices P and Q (if they exist) such that PAQ is a canonical form of A. The pertinent theory of fully indecomposable matrices is discussed and detailed description is given of the algorithm by Dulmage and Mendelsohn. The connection between irreducible and fully indecomposable matrices is also examined, and it is observed that Harary's algorithm for bringing a matrix to a normal form is interchangeable with the second part of the Dulmage and Mendelsohn algorithm. Efficient computer programs for the Dulmage and Mendelsohn algorithm are presented which are directly applicable to various numerical problems.

abstract: Thesis

abstract: Master of Science (MS)


title: HARD WORKING BUT HARDLY WORKING:  A CASE STUDY OF KOREAN SKILLED IMMIGRANTS IN THE CANADIAN LABOUR MARKET

contributor:
Carranza, Mirna
Social Work

subject:
immigration
Korean skilled immigrants

abstract:
The dominant discourse in Korea is that Canada is a multicultural country wherein no racial discrimination exists. This significantly contributes to making Canada their first choice of destination. The purpose of this study was to explore the barriers faced by Korean skilled immigrants in the Canadian labour. This thesis presents the findings of a qualitative study. Six participants were interviewed, who have lived in Canada for at least three, and using a semi-structured interview guide. Interviews were conducted in Korean, transcribed and later translated for analysis. Critical Race Theory and Democratic Racism were used as theoretical frameworks. This informed a critical review of major theoretical concepts, data collection and analysis.
The findings indicate that structural exclusion was a significant barrier faced by the participants. Structural exclusion includes lack of recognition of international knowledge; conventional hiring practice in Canada; accented English; and settlement services not meeting the needs of skilled immigrants. Also, it was found that as their state of unemployment or underemployment continued for a long time, they experienced loss of identity and low self-esteem. Furthermore, how they respond to such exclusion was too a significant finding. While some of the participants sought to take additional Canadian education in order to overcome the barriers, others gave up efforts to integrate into the mainstream or were planning to go back to Korea.

abstract: Thesis

abstract: Master of Social Work (MSW)


title: Perceived risk of falling: The relationship to balance and falls in community-dwelling older adults with type 2 diabetes mellitus

contributor:
Richardson, Julie
Rehabilitation Science

subject: Perceived risk, balance, falls, older adults, type 2 diabetes mellitus

abstract: The purpose of this thesis was to determine the perceived risk of falling and its relationship to balance and falls in older community-dwelling adults with type 2 diabetes mellitus (DM2). Study One was a systematic review of published literature on risk factors for falling in older adults with DM2. Study Two was a prospective cohort study for parameter estimation, the goal was to determine the test-retest reliability, internal consistency, construct validity and factor structure of a falls Risk Perception Questionnaire in older community-dwelling adults with DM2. Study Three was also a prospective cohort study; the goals of this study were to determine the association between perceived of falling and balance in older adults with DM2 and to determine whether older adults alter their perceived risk of falling after receiving feedback about their balance. The information gained from these studies will be used to guide subsequent research as well as falls risk assessment and prevention in older adults with DM2.

abstract: Thesis

abstract: Master of Science (MSc)


title: Voice Capacity in Opportunistic Spectrum Access Networks with Friendly Scheduling

contributor:
Todd, Terry
Electrical and Computer Engineering

subject:
Quality of Service
Scheduling Algorithms
Cognitive Radio Networks (CRN)
Real-time Systems
Opportunistic Spectrum Access (OSA)
VoIP Capacity
Secondary Networks
Integer Linear Program (ILP)
Secondary Friendliness
Relay Placement

abstract:
Radio spectrum has become increasingly scarce due to the proliferation of new wireless communication services. This problem has been exacerbated by fixed bandwidth licensing policies that often lead to spectral underutilization. Cognitive radio networks (CRN) can address this issue using flexible spectrum management that permits unlicensed (secondary) users to access the licensed spectrum. Supporting real-time quality-of-service (QoS) in CRNs however, is very challenging, due to the random spectrum availability induced by the licensed (primary) user activity. This thesis considers the problem of real-time voice transmission in CRNs with an emphasis on secondary network ``friendliness''. Friendliness is measured by the secondary real-time voice capacity, defined as the number of connections that can be supported, subject to typical QoS constraints.

The constant bit rate (CBR) air interface case is first assumed. An offline scheduler that maximizes friendliness is derived using an integer linear program (ILP) that can be solved using a minimum cost flow graph construction. Two online primary scheduling algorithms are then introduced. The first algorithm is based on shaping the primary spectral hole patterns subject to primary QoS constraints. The second applies real-time scheduling to both primary traffic and virtual secondary calls. The online scheduling algorithms are found to perform well compared to the friendliness upper bound. Extensive simulations of the primary friendly schedulers show the achievable secondary voice capacity for a variety of parameters compared to non-friendly primary scheduling.

The thesis then considers the variable bit rate (VBR) air interface option for primary transmissions. Offline and online approaches are taken to generate a primary VBR traffic schedule that is friendly to secondary voice calls. The online VBR schedulers are found to perform well compared to the friendliness upper bound. Simulation results are presented that show the effect of the primary traffic load and primary network delay tolerance on the primary network friendliness level towards potential secondary voice traffic.

Finally, secondary user friendliness is considered from an infrastructure deployment point of view. A cooperative framework is proposed, which allows the primary traffic to be relayed by helper nodes using decode-and-forward (DF) relaying. This approach decreases the primary traffic channel utilization, which, in turn, increases the capacity available to potential secondary users. A relay selection optimization problem is first formulated that minimizes the primary channel utilization. A greedy algorithm that assigns relay nodes to primary data flows is introduced and found to perform well compared to the optimum bound. Results are presented that show the primary network friendliness for different levels of primary channel utilization.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)


title: Advances in Design, Optimization and Control of Semicontinuous Distillation Processes

contributor:
Adams II, Thomas A.
Chemical Engineering

abstract:
Semicontinuous distillation is a process intensification technique for purification of ternary mixtures to desired specifications. Where conventional continuous process requires two distillation columns for ternary separation, a semicontinuous process utilizes only one distillation column and integrates it with a simple storage tank (called middle vessel) to perform the same task. Therefore, with a lower total direct cost, a semicontinuous system has a lower total annualized cost (TAC) for low to intermediate production rates compared to the continuous configuration. However, the operating cost of the semicontinuous system is higher than the continuous counterpart.
The objective of this thesis is to improve the economics of semicontinuous distillation by reducing the operating cost and the TAC of the process. This study investigates potential enhancements of the process by modifying the design, optimizing the design parameters and implementing more efficient control strategies on the process.
In this work, a novel intensification technique for purification of ternary mixtures is proposed. The process can purify three components to desired purities in a single distillation column without the necessity of a middle vessel and is called semicontinuous without middle vessel (SwoMV). The proposed configuration reduces the side stream recycling and consequently lowers the operational and the direct costs of a semicontinuous process.
Subsequently, the integration of design and control of semicontinuous processes is studied. A methodology is presented to simultaneously obtain locally-optimal structural and operational parameters of the system to minimize the TAC of the process. A mixed integer dynamic optimization (MIDO) problem is formulated and the outer approximation (OA) and the particle swarm optimization (PSO) methods are used to solve the problem.
Finally, for the first time, the implementation of model predictive control (MPC) on the semicontinuous process is studied. The subspace identification method is adopted to identify a linear state-space model. Subsequently, a shrinking horizon MPC is implemented on the system to reduce the operating cost of the process while maintaining the desired product purities by the end of the cycle.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Larp & Narrative

contributor:
Donaldson, Jeffery
English and Cultural Studies

subject:
live action roleplaying
larp
narrative
play

abstract:
Live action role-playing (larp) is a form of narrative play that engages participants in fictional
words within the dialectic of experience (unorganized time) and narrative (organized time). In this thesis I explore the complexities of the fictional worlds created by larps and how the participation in larps constructs requires a different engagement with traditional thoughts about narrative. Discussing fictional worlds theory, Aristotle, Frye, and Ricoeur along side concepts from game studies, such as the magic circle and the frames of exogeny, endogeny, and diegesis, I propose an alternative approach to understanding narrative within larps that looks at the larp worlds and plot as being driven by a process of affirming the identities constructed to participate within the fictional worlds through the mimetic process.

abstract: Thesis

abstract: Master of Arts (MA)


title: Contributions to the Testing of Benford's Law

contributor:
Hoppe, Fred
Statistics

abstract:
Benford’s Law is a statistical phenomenon stating that the distribution of leading digits
in a set of naturally occurring numbers follows a logarithmic trend, where the distribution
of the first digit is P(D1 = d1) = log(1+1/d1), d1 ϵ {1,2, ...,9}. While most
commonly used for fraud detection in a variety of areas, including accounting, taxation,
and elections, recent work has examined applications within multiple choice
testing. Building upon this, we look at test bank data from mathematics and statistics
textbooks, and apply three commonly used conformity tests: Pearson’s chi-square, MAD,
and SSD, and two simultaneous confidence intervals. From there, we run simulation
studies to determine the coverage of each, and propose a new conformity test using
linear regression with the inverse of the Benford probability function. Our analysis
reveals that the inverse regressionmodel is an improvement upon the chi-square goodness of
fit test and the regression model that was previously proposed in 2006 by A.D. Saville;
however, still presents some asymptotic issues at large sample sizes. The proposed
method is compared to the previously utilized tests through numerical examples.

abstract: Thesis

abstract: Master of Science (MSc)


title: Landsystem analysis of three outlet glaciers, southeast Iceland

contributor:
Maclachlan, John C.
Eyles, Carolyn H.
Earth Sciences

subject:
Glacial Geomorphology
Glacial Sedimentology
Landsystem Analyis

abstract: Landsystem analysis is a commonly applied methodology which focuses on process-form relationships when applied in glacial environments.   It can be used to understand and recreate the geomorphological evolution of glacial deposits from modern and ancient sediments.  The purpose of this study is to examine the forefields of three closely located outlet glaciers of the Vatnajökull Ice Cap in southeast Iceland to determine the factors affecting the landsystems of these glaciers.  A combination of digital based methods and field work focusing on geomorphology and sedimentology were used to define the landsystems. A classification code and associated symbology was used in this study to create consistency of landsystem analysis and can be used in future similar studies of glacial environments.  The three glaciers, Morsárjökull, Skaftafellsjökull and Svínafellsjökull were chosen due to their shared source and close proximity, lying within adjacent valleys.  The historical changes of the three glaciers have been well documented with aerial photographs, historical maps and glacier margin measurements. LiDAR were used to interpolate 2 m digital elevation models (DEM) of the three glacier forefields. These glaciers have varying topography, bedrock type and ice distribution (hypsometry, equilibrium line altitude (ELA)) which impacts the deposition at the glacier margin.  The forefields of Morsárjökull and Skaftafellsjökull exhibit many similarities in the distribution and scale of landforms similar to the characteristics of the established active temperate landsystem commonly found in Iceland.  However, the forefield of Svínafellsjökull has many differences compared to Skaftafellsjökull and Morsárjökull in the scale, type and distribution of landforms and sediments.   Bedrock type, hypsometry and glacial debris content are major factors that influence differences in these landsystems.   These three forefields may be used as analogues to enhance understanding of paleoenvironmental conditions that existed along the southern margin of Pleistocene glaciers that covered much of northern North America and Europe in the past.

abstract: Thesis

abstract: Master of Science (MSc)


title: The Effects of Parental Carbamazepine and Gemfibrozil Exposure on Sexual Differentiation in Zebrafish (Danio rerio)

contributor:
Wilson, Joanna Y
Biology

subject:
Carbamazepine
Gemfibrozil
Pharmaceuticals
Development
Sexual Differentiation
Sex Ratio
Fish
Zebrafish
Parental Effects
Parental Exposure
F1 Offspring
Chemical Stressors
Environment
Toxicology
Aquatic Toxicology
Endocrine Disruption
Gonads
Histology

abstract: Endocrine-disrupting compounds (EDCs) interfere with the physiology of hormone systems. Traditionally, steroidogenic pharmaceuticals have been studied as EDCs however there has been growing evidence that non-steroidogenic pharmaceuticals can alter sex steroid levels and impair reproductive functions in fish. This is of concern as pharmaceuticals are detected in surface waters at the ng L-1 to µg L-1 range. Zebrafish (Danio rerio) were exposed to 10 µg L-1 of the pharmaceuticals carbamazepine and gemfibrozil for 6 weeks. Male-biased sex ratios were observed in the sexually mature offspring after paternal exposure, suggesting that sexual differentiation may be impacted in juveniles. Currently, the ability of pharmaceuticals to interfere with sexual differentiation of parentally exposed offspring is unknown. This thesis examined the gonad histology of juvenile zebrafish to understand how sexual differentiation was affected in the offspring of exposed parents. Paternal, but not maternal, exposure to carbamazepine resulted in a significantly faster sexual differentiation of the gonads and led to a male-biased sex ratio; these effects were not observed when both parents were exposed. Combined paternal and maternal exposure to gemfibrozil resulted in significantly faster sexual differentiation and paternal, but not maternal, exposure to gemfibrozil led to male-biased sex ratios. Interestingly, sex ratios observed in the juveniles did not always reflect those found in the same lineage at sexual maturity, suggesting a sex reversal, including a male to female transition, occurred past the juvenile sexual differentiation period in some fish. This thesis demonstrates that pharmaceuticals have the ability to disrupt sexual differentiation in the F1 offspring of exposed parents and that paternal exposure is most relevant for offspring effects.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: Parental exposure to the environmentally-relevant pharmaceuticals carbamazepine or gemfibrozil led to male-biased sex ratios in adult offspring of zebrafish (Danio rerio), a common model organism. The development of the gonads in juveniles was investigated to determine how this process was impacted. Predominately, paternal exposure was found to result in a faster development of the testes and male-biased sex ratios. Interestingly, sex ratios in juveniles did not always reflect those in adults, suggesting a sex reversal may have occurred in adulthood. This study demonstrates the ability of pharmaceuticals to alter gonad development in offspring of exposed parents.


title: Optimization-based Microgrid Energy Management Systems

contributor:
Sirouspour, Shahin
Emadi, Ali
Electrical and Computer Engineering

subject:
Energy Management
Smart Grids
Microgrids
Optimization
Model Predictive Control
Rolling Horizon
Chance Constraints
ADMM
Electric Vehicles

abstract:
Energy management strategies for microgrids, containing energy storage, renewable energy sources (RES), and electric vehicles (EVs); which interact with the grid on an individual basis; are presented in Chapter 3. An optimization problem to reduce cost, formulated over a rolling time horizon, using predicted values of load demand, EV connection/disconnection times, and charge levels at time of connection, is described. The solution provides the on-site storage and EV charge/discharge powers. For the first time, both bidirectional and unidirectional charging are considered for EVs and a controller which accommodates uncertainties in EV energy levels and connection/disconnection times is presented. In Chapter 4, a stochastic chance constraints based optimization is described. It affords significant improvement in robustness, over the conventional controller, to uncertainties in system parameters. Simulation results demonstrate that the stochastic controller is at least twice as effective at meeting the desired EV charge level at specific times compared to the non-stochastic version, in the presence of uncertainties.
In Chapter 5, a network of microgrids, containing RES and batteries, which trade energy among themselves and with the utility grid is considered. A novel distributed energy management system (EMS), based on a central EMS using a Multi-Objective (MO) Rolling Horizon (RH) scheme, is presented. It uses Alternating Direction Method of Multipliers (ADMM) and Quadratic Programming (QP). It is inherently more data-secure and resilient to communication issues than the central EMS. It is shown that using an EMS in the network provides significant economic benefits over MGs connected directly to the grid. Simulations demonstrate that the distributed scheme produced solutions which are very close to those of the central EMS. Simulation results also reveal that the faster, less memory intensive distributed scheme is scalable to larger networks -- more than 1000 microgrids as opposed to a few hundreds for the central EMS.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Theoretical Study of Inhomogeneous Polymeric Systems

contributor:
Shi, An-Chang
Physics and Astronomy

subject:
Polymer Physics
Block Copolymers
Self-Consistent Field Theory
Polyelectrolytes

abstract:
In this thesis, we use the self-consistent field theory (SCFT) to study neutral and charged block copolymer melts and blends in thin films and bulk. We showcase the utility of the SCFT by applying it to a number of different model systems.
In our first study, we examined the elastic properties of multi-component bilayer membranes composed of amphiphilic AB/ED diblock copolymers. We focused on the effects of chain architecture and interactions between the amphiphilic molecules on the line tension or edge energy of a membrane pore. We discovered a direct relationship between the effective volume of the amphiphilic molecules, which is dictated by their architecture, and the line tension. We found that the addition of cone-shaped molecules to the membrane results in a decrease in the line tension. The opposite effect is seen for inverse cone-shaped amphiphiles, where an increase in their concentration results in an increase of the line tension.
Studies two and three fall under the theme of directed self assembly of block copolymer thin films. First we examined the effects of ion concentration on the strength of the external electric field required to reori- ent lamellar domains from the parallel to the perpendicular orientation. The change in the critical electric field is found to be dependent on whether the neutral or charged polymer species is favoured by the top and bottom surfaces. In the second study, we examined the mechanism of using the entropic effect to direct the self assembly of micro domains in star block copolymer thin films. We control the architecture of star block copolymers by varying the number of arms, ranging from a linear chain with 1-arm to 4-arm star block copolymers. Using both experiments and SCFT, we showed that the entropic effect is enhanced in star block copolymer blends with greater number of arms. Furthermore, we showed that the entropic effect can be used to direct the self assembly of micro domains perpendicular to the substrate.
In our last study, we examined the unbinding transition of the α-BN phase in pentablock terpolymer/ homopolymer blends. We constructed a phase diagram of the system as a function of homopolymer con- centration. We discovered that the unbinding transition is preempted by the macrophase separation of the blends into block copolymer rich/ homopolymer rich domains.
The results presented in this thesis help advance our understanding of various properties of polymeric systems, such as the elastic properties of multi-component membranes, directed self assembly in block copolymer thin films and the phase behaviour of block copolymers in bulk.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Recall of compound words in simple and complex span tasks

contributor:
Service, Elisabet
Cognitive Science of Language

subject:
working memory
mental lexicon
simple span
complex span
memory
compound words

abstract: There has been little research exploring whether different memory processes (i.e. related to short term memory (STM), working memory (WM) and long term memory (LTM) may be differentially sensitive to representation and processing aspects of compound words. This study investigated how compound words are represented in STM in immediate serial recall tasks and in WM in complex span tasks that combine processing and storage demands. The simple span STM task was comprised of solely a list of memory words, whereas the two complex span WM tasks interleaved sentence processing between presentation of memory words. They varied in the presence of a pause after presentation of each memory word and before onset of the following distractor sentence for processing. The absence of a pause was intended to minimize opportunity for subvocal rehearsal, whereas the presence of a pause encouraged rehearsal. To increase chances of recombination errors for error analyses, lists of memoranda were manipulated so that each set (list) of four compound words contained one “lure” pair (e.g. pinstripe + warhead = pinhead) in which the modifier and head constituents from separate compound words could recombine to form a new, legal word.  Recall performance was better in the simple span and complex span pause tasks compared to the complex span no pause task. Whole compound and left constituent frequencies played opposite roles, helping and harming, respectively. Error types reflecting decomposition of the compound words to their constituents were more common in simple span than in complex span. Omissions were more common in complex span. We discuss how different memory processes may be differentially sensitive to representation and processing aspects, and how recall of compound words is affected by various lexical variables.

abstract: Thesis

abstract: Master of Science (MSc)


title: 237Np, 238Np, 235U, 233U, and 239Pu; Fission Yield Studies

contributor:
Thode, H. G.
Physics

subject: fission, yield, thermal, neutron, krypton, xenon, charge

abstract:
 The relative cumulative yields of krypton and xenon isotopes from the thermal neutron fission of 237Np and Np238 and from the fast neutron fission of Np237 have been measured by means of a mass spectrometer. These are the first fission yield results for 238Np, and the first for 237Np at thermal neutron energies. The results are compared with those from other fissioning nuclides.

 Independent yields of the shielded nuclides 80Br, 82Br, 128I, and 130I from the thermal neutron fission of 235U, 233U, 239Pu, and 238Np have been determined by mass spectrometric analyses of the krypton and xenon β-decay products. The results are discussed in terms of conventional charge distribution theories, and also in terms of neutron emission effects.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: METABOLITE CONCENTRATIONS IN THE ANTERIOR CINGULATE CORTEX: A STUDY OF CHILDREN WITH ATTENTION-DEFICIT HYPERACTIVITY DISORDER AND OBSESSIVE-COMPULSIVE DISORDER

contributor:
Hall, Geoffrey
Psychology

abstract: The dorsal anterior cingulate cortex (ACC) plays an important role in attention and cognitive control (Bush et al., 2000; Margulies et al., 2007; Shackman et al., 2011). Individuals with neurodevelopmental disorders often struggle with inattention, hyperactivity, and repetitive behaviours, which is indicative of deficits in the ACC (Baribeau et al., 2015; Bush et al., 1999; Fitzgerald et al., 2005). This study investigated metabolite abnormalities in the ACC of two groups of children with neurodevelopmental disorders. Participants were children with obsessive-compulsive disorder (i.e., OCD; n = 24) and children with attention-deficit hyperactivity disorder (ADHD; n = 29). Participants completed cognitive and clinical testing and proton magnetic resonance imaging (1H-MRS) of the ACC. Children with ADHD had higher concentrations of N- acetyl aspartate than those with OCD. In the OCD group, creatine concentrations were correlated with scores on the Children’s Yale-Brown Obsessive-Compulsive Scale (CY- BOCS). Across diagnostic groups, concentrations of N-acetyl aspartate predicted scores on the anxious/depressed syndrome scale of the Child Behaviour Checklist (CBCL), and creatine, myo-inositol, and glutamate concentrations predicted scores on the affective problems syndrome scale of the CBCL. This study was the first to compare two groups of children with neurodevelopmental disorders using 1H-MRS, and the first to look the relationship between metabolites and symptom dimensions (i.e., CBCL syndrome scales) rather than the relationship between metabolites and symptom severity alone. Our findings support an interdisciplinary approach to studying neurodevelopmental disorders, and invite future investigations combining 1H-MRS with anatomical and functional imaging techniques.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: The current study investigated concentrations of metabolites in the brains of children with neurodevelopmental disorders. We focused on a structure called the anterior cingulate cortex (ACC), which is largely responsible for attention and cognitive control, processes that are impaired in individuals with neurodevelopmental disorders. Participants with OCD (n = 24) and ADHD (n = 29) completed clinical testing and neuroimaging. We found differences in N-acetyl aspartate, a metabolite related to the number of neuronal connections in a given region, between the groups. Across groups, there were associations between metabolite concentrations and symptom dimensions, including anxiety/depression and affective problems. Overall, this study suggests that an interdisciplinary approach to studying children with neurodevelopmental disorders could reveal information about the underlying deficits common in all neurodevelopmental disorders.


title: Coulomb Effect on the Proton-Proton Low Energy Scattering Parameters and Separable Potentials

contributor:
Nogami, Y.
Physics

subject: coulomb, proton-proton, low-energy, separable potentials, nuclear forces

abstract:
 We study the Coulomb effect on the proton-proton low-energy scattering parameters when all other effects are represented by a separable potential.

 For this purpose, we present a formulation for the scattering of two particles via a separable potential. We treat the same problem when any potential, particularly a Coulomb potential or a separable potential, is added to the separable potential. The properties of scattering from a separable potential plus a (local or non-local) potential lead us to the possibility of obtaining a one term separable potential equivalent to a two term separable potential, and a model for the nuclear potential as a sum of a separable potential and a non-separable potential.

 We determine, to the first order in Me^2/β where β^-1 is the range of the separable potential, the parameters for Yamaguchi's and Naqvi's separable potentials from proton-proton scattering data. We use these parameters to calculate the low-energy proton-proton scattering parameters when the Coulomb interaction is removed. Our results show that the shape dependence of these parameters are somewhat larger than obtained by Heller et al in their investigation on local potentials. Implications of our results concerning the charge symmetry and charge independence of the nuclear forces are discussed.

abstract: Thesis

abstract: Master of Science (MSc)


title: The Political Behaviour of Youth in Whitefish River First Nation

contributor:
Bird, Karen
Political Science

subject: First Nations Youth, Political Participation, Youth Engagement, Youth Political Behaviour, Politics, Reserve, Community-Based Action Research, Indigenous Research

abstract:
This dissertation considers the political behaviour of youth in Whitefish River First Nation. This small Ojibway community located near Sudbury, Ontario is used as a case study to inquire into the political experiences, attitudes and behaviour of youth. Rooted in Community-Based Research and Indigenous Research Principles, conversations were carried out in a circle-method referred to as Discussion Circles to assess the political behaviour of youth between the ages of 16 and 25. While this study is heavily qualitative-focused, it includes some quantitative components. These include a youth political participation questionnaire and electoral participation data for Whitefish River First nation in federal, provincial and band elections.
	Results demonstrate that the youth have a unique experience of politics defined by their identities, community and relationships. Their political behaviour is complex and nuanced. While they may not participate in conventional political activities, they are heavily involved in activities that are rooted in their culture and traditions. The community overall is democratically healthy and tends to participate widely in federal and provincial elections. Youth are for the most part satisfied with their lives in the community, but there are significant challenges due to the consequences of colonialism. Many of these implications affect their political behaviour.

abstract: Thesis

abstract: Master of Arts (MA)


title: New Aspects of Data Acquisition and Reduction in Gel Permeation Chromatography

contributor:
Hamielec, A. E.
Wright, J. D.
Chemical Engineering

subject: data acquisition, gel permeation, chromatography, reduction system, polymer composition

abstract:
 The work of this study is divided into two parts. Part I reports on the development of a dedicated minicomputer, data acquisition, and reduction system for GPC. The hardware, software, and operating performance of the system is discussed in some detail.

 Part II, reports on an experimental study design to determine whether axial dispersion corrections are universal in the sense of being independent of polymer composition. Results for poly(vinyl-chloride), polystyrene, polybutadiene, and poly(methy-methacrylate) are discussed.

abstract: Thesis

abstract: Master of Engineering (MEngr)


title: Portrayals of the Virgo in Plautine Comedy

contributor:
Kathryn, Mattison
Classics

subject:
Roman Comedy
Virgo
Characterization
Latin literature
Plautus

abstract: This thesis presents a literary study of three subtypes of the maiden stock character in Plautine Comedy: the silent virgo, the meretrix-virgo, and the virgo in transition. The comic maiden is remarkable in Roman Comedy, in that she is the female protagonist of most if not all of the plays in which she is a character, although she sometimes never appears onstage. The aim of this thesis is to investigate how the playwright manages and enrichens his portrayals of the virgo despite her limitations, and to analyze her significance in the broader themes of her plays. This has been done by detailed character analyses of three of Plautus’ plays, each of which features a virgo who represents one of the three subtypes of the comic maiden (i.e. Phaedria from Plautus’ Aulularia, Palaestra from Plautus’ Rudens, and Alcmena from Plautus’ Amphitruo respectively). Through the examination of the characters’ speeches and conversations, including those presented by the maiden herself when she appears onstage, it is evident that the virgo is a central figure in tensions and conclusions driving the plot. Because of her contradictory circumstances (i.e. her premarital pregnancy, slave status, or change in stock role), this integral function is contingent on her piety and innocence, which must be maintained throughout the play. Finally, the propitious resolution of the plot comes about in the restoration of the maiden’s status and the promise of marriage between her and the male lover. Because of this, she is also deeply connected to the underlying themes of morality and communal bonds governing the play. This research highlights the valuable and central role of a character in Plautine comedy, whose on-stage presence is often limited or even non-existent.

abstract: Thesis

abstract: Master of Arts (MA)

abstract: This thesis analyzes the portrayals of three subtypes of the virgo or maiden stock character in the comedies of Plautus, a Roman playwright who flourished in the late third to early second centuries BCE. More specifically, this thesis presents a detailed character study of Phaedria as the silent maiden in Aulularia, Palaestra as the prostitute-maiden (meretrix-virgo) in Rudens, and Alcmena the maiden in transition in Amphitruo. The aim is to investigate how Plautus manages and enrichens his characterization of these maidens, as well as their significance in the broader themes of the plays. Through the textual analyses of characters’ speeches and dialogues, this research highlights the centrality of the virgo in the tensions and resolutions driving the plot, and her connection to the underlying themes of morality and communal bonds in Plautus’ plays.


title: Components of Variance Analysis

contributor:
Bankier, J. D.
Mathematics

subject: components, variance analysis, theory of regression, matrix

abstract: In this thesis a systematic and short method for computing the expected values of mean squares has been developed. One chapter is devoted to the theory of regression analysis by the method of least squares using matrix notation and a proof is given that the method of least squares leads to an absolute minimum, a result which the author has not found in the literature. For two-way classifications the results have been developed for proportional frequencies, a subject which again has been neglected in the literature except for the Type II model. Finally, the methods for computing the expected values of the mean squares are applied to nested classifications and Latin square designs.

abstract: Thesis

abstract: Master of Arts (MA)


title: Rocking Response of Slender Freestanding Building Contents in Fixed-Base and Base-Isolated Buildings

contributor:
Konstantinidis, Dimitrios
Tait, Michael J.
Civil Engineering

subject:
Rocking
Overturning
Nonstructural Components
Building Contents

abstract:
The primary seismic response mode of freestanding slender building contents is rocking. Rocking is one of the most damaging response modes due to large accelerations at impact and the possibility of toppling. This study investigates the rocking response of contents within fixed-base and base-isolated buildings so that better-informed decisions can be made, either at the design stage for new structures or during the performance evaluation for existing structures, to mitigate the effects of the destructive rocking behaviour and consequently minimize injury, economic loss, and downtime.
	A 3D model of a hospital building was created in OpenSees and analyzed to obtain floor accelerations for a suite of 20 broadband ground motions. These motions were then used as input to compute the rocking responses of many building contents. The rocking responses were compared and contrasted to determine the effect of the block’s size, slenderness, floor level, and placement within a level. The rocking response of contents in buildings isolated with lead plug and triple friction pendulum bearings were compared to the fixed-base building to determine the effectiveness of isolation as a means to control rocking. Fragility curves were also created for the fixed-base and isolated buildings.
	The vertical component of the floor accelerations had little effect on the rocking response of contents. The significance of this is that the location of an object on a given story does not affect its rocking response. However, higher vertical accelerations did increase the likelihood of the object lifting off the floor. The rocking response of stocky contents increased from one story to the next, but as the slenderness increased this transition became less evident. Base isolation was found to be effective at reducing both the likelihood to uplift and overturn. The longer period systems provided superior protection despite the long period pulse like motion while the damping of the systems had little effect on the rocking response.

abstract: Thesis

abstract: Master of Applied Science (MASc)

abstract: During an earthquake slender building contents respond by rocking about their edges. Rocking causes damage to sensitive and brittle objects as well as safety hazards if it results in the overturning of heavy objects. One goal of this study was to define the rocking response of rigid contents in a conventional braced frame hospital. In general, larger and stockier objects were less likely to overturn. Also, overturning was more prevalent higher up in the building while the location of an object within a given story had little effect. Another objective was to determine the effectiveness of base isolation, a technique that decouples the motion of the building from the ground using flexible bearings, as a strategy to protect contents that are vulnerable to rocking during an earthquake. This was found to be quite effective at reducing both the occurrence of uplift (the initiation of rocking) as well as toppling.


title: Hydrogeological Assessment at The Clarington Transformer Station Using a Conventional Well Cluster with Recommendations to Establish an Advanced Groundwater Monitoring Station

contributor:
Smith, James
Parker, Beth
Earth and Environmental Sciences

subject:
Hydrogeology
Newmarket Till
Oak Ridges Moraine
Groundwater
Quaternary Sediments

abstract: Aquifers associated with the Oak Ridges Moraine (ORM) supply drinking water to more than 200,000 people. These aquifers are often overlain by relatively lower permeability till deposits (aquitards) often considered to provide protection to underlying aquifers. A transformer station is under construction by Hydro One (H1) on 11 hectares of H1 owned land on the ORM in the Municipality of Clarington, Ontario. The surficial geology is mapped as till. It is important to consider potential groundwater impacts of this transformer project. As part of the environmental assessment conducted by H1, groundwater information was collected from the property and from nearby homeowner wells. This thesis concerns the geology and groundwater conditions beneath the property utilizing both existing information and also study of a drill hole, commissioned by H1, continuously cored into bedrock at 127.76 m depth. There is a paucity of deep hydrogeological information over the eastern half of the ORM. This thesis reports on the hydrogeology of the local area, which is in a hydrologic setting common throughout much of the ORM, thereby providing valuable information to inform the regional context. The cored hole showed the presence of two deep regional sand aquifers, known as the Thorncliffe and Scarborough aquifers, overlying bedrock. The surficial till unit is interpreted to be over 75 m thick and includes a near-surface sand layer and two deeper, thin sandy layers within this very dense till. This study, conducted as a collaboration between the Universities of Guelph and McMaster, represents the first phase of a continuing study of the hydrogeology of the H1 property and adjacent area. The next phase includes installation of a depth-discrete, multilevel monitoring system (MLS) for water level measurement and groundwater sampling at 16 different depths. This thesis includes a design for this MLS to be installed beside the deep hole.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: This thesis concerns the geology and groundwater conditions at the Hydro One transformer station under construction in the Municipality of Clarington, located near the southwestern periphery of the Oak Ridges Moraine (ORM). The ORM, throughout its full extent north of Lake Ontario, has aquifers supplying drinking water to more than 200,000 people, some near the transformer station. The thesis, which is the first phase of a longer term study, uses information obtained from a borehole that provided continuous core samples from near ground surface down through deposits formed by Pleistocene glaciers and into the shale bedrock at 127 m depth. This borehole and four monitoring wells installed by Hydro One nearby, provide the first deep groundwater information of its type available from this part of the ORM and indicate the presence of two deep regional sand aquifers and suggest the occurrence of two thin intermediate depth sand aquifers.


title: Studies of Energy Transfer Processes in Mammalian Mitochondria

contributor:
Ziegler, F. D.
Biochemistry

subject: energy transfer processes, Mammalian, mitochondria, oxidative phosphorylation

abstract:
 The present investigation was concerned with mitochondrial energy transfer reactions and their relationship to mitochondrial structural integrity. Experiments with azide demonstrated a close relationship between oxidative phosphorylation and large amplitude
mitochondrial volume changes. Azide inhibited energy transfer and energy-linked mitochondrial swelling by competing with adenine nucleotide for a site on the terminal phosphorylating enzyme. As a permeant anion azide exerted secondary effects on mitochondrial structure and function.

 Experiments with mitochondria treated with phlorizin and phloretin emphasized the importance of Mg++ as a controlling factor in maintaining the integrity of mitochondrial energy transfer processes. The results indicated that these compounds interfered directly with oxidative phosphorylation, and that mitochondrial swelling was either a consequence of impaired energy transfer, or a separate phenomenon.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


contributor:
Woo, M.K.
Geography

abstract: Title: Effects of Beaver Dams on Subarctic Wetland Runoff, Author: James M. Waddington, Location: Thode

abstract:
Beaver dams located on streams of a western James Bay marsh were studied to determine their effects on the runoff from subarctic wetlands. A survey of the location, type, class, and geometry of 50 dams on five different creeks were related to streamflow hydrographs from 1987 field season. The hydrographs showed that although gapflow and overflow type dams stored more water upstream during low flow, little alteration to stormflow occurred except for the shedding of water to the surrounding wetland. Throughflow type dams
altered streamflow only at the local scale, while underflow type beaver dams, despite having little affect at low flow, created a 12 hour time lag and a long hydrograph recession during high flows.

A water balance comparison was performed for the period June 18th to July 28th, 1988 between a basin without a beaver dam and one dammed by the beaver to determine the effects of the beaver dams at the basin scale. The amount of water stored in the beaver dam basin (18mm) was 53mm greater than that stored in the basin without a dam (-35mm) indicating a distinct difference in the basins' abilities to store water. In both basins, net subsurface flow was negligible. Precipitation was similar in magnitude between the two basins. Net surfaceflow in the beaver dam basin was 43mm compared to -28mm in the beaver dam-less basin. The beaver dam was responsible for preventing a portion of inflow from leaving the basin, and consequently caused the increase in storage. Increased evaporation occurred because of the larger ponded area upstream from the beaver dam which in turn decreased the amount of water stored in the basin. Downstream streamflow ceased during dry periods because of the loss and storage of water from the system upstream.

abstract: Thesis

abstract: Bachelor of Arts (BA)


title: Atomic Compactness in Quasi-Primitive Classes of Structures

contributor:
Banaschewski, Bernhard
Mathematics

subject: atomic compactness, quasi-primitive classes, structures

abstract:
Abstract Not Provided
Thesis
Master of Science (MSc)


title: NEW CLINICAL AND INVESTIGATIVE TOOLS FOR EVALUATING THROMBOSIS AND HAEMOSTASIS

contributor:
Gross, Peter L
Medical Sciences

subject:
Haemostasis
Thrombosis
Coagulation
Murine bleeding models
Microparticles
Whole blood thrombin generation assay
Platelets

abstract: Haemostasis is maintained by a dynamic balance between pro- and anti-thrombotic mediators. Its dysregulation can lead to bleeding or thrombosis, and is a major cause of morbidity and mortality. Thus, elucidation of the mechanisms involved in maintaining or disrupting this balance have important implications in health and disease. Investigative tools enable characterization of the haemostatic system, but are often associated with limitations. For instance, haemostasis in animal models is often investigated by assessing bleeding responses in one particular vessel or tissue without a complete understanding of how the results translate to the regulation of haemostasis in other vascular beds.  As a second example, microparticles (MPs) are a heterogeneous population of submicron-sized vesicles that may be important in thrombosis. With the exception of a few subtypes, MPs cannot be reliably characterized using widely accessible techniques. Finally, the thrombin generation assay (TGA), which measures ex vivo activation and inhibition of thrombin, is a promising tool for clinical assessment of thrombosis and haemostasis.  However, characterization of thrombin generation in the general population, and the development of point of care testing are in their infancies. As a result, the TGA remains largely a research tool.  The works described in this thesis specifically seek to address these three limitations in thrombosis and haemostasis research. The first isolated murine arterial bleeding model is presented and its characterization with respect to bleeding in other vascular tissues is described. In addition, a solid-phase capture assay for evaluating procoagulant, P-selectin-binding MPs, which are postulated to be mediators of thrombosis, was developed in order to determine whether these MPs associate with risk of recurrent venous thromboembolism. Lastly, a 25 x 20 mm chip that performs four individual thrombin generation assays using ~10 µl of capillary blood was developed as a proof of concept for point of care thrombin generation testing.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: A Mechanistic Model to Predict Fuel Channel Failure in the Event of Pressure Tube Overheating

title: A Model to Predict Fuel Channel Failure

contributor:
Luxat, John
Engineering Physics

subject:
Thermal Hydraulics
CANDU
Fuel Channel Failure
Film Boiling

abstract: Under normal operating conditions a CANDU reactor pressure tube (PT) is insulated from its outer calandria tube (CT) by a CO2 gas annulus. If the primary loop coolant flow is compromised the PT can overheat and, if still pressurized, balloon into contact with the CT. At this point the moderator acts as an emergency heat sink. If the heat transferred from the CT to the moderator exceeds the critical heat flux (CHF) the CT can overheat, begin to strain due to the contact pressure, and eventually fail. A mechanistic model is presented that describes ballooning contact of the PT and CT, the resulting thermal contact conductance, heat flux to the moderator, and, if CHF is exceeded, the development of film boiling and potential CT strain. The goal is to create a software package that predicts fuel channel failure during a pressure tube overheat event.

abstract: Thesis

abstract: Master of Applied Science (MASc)

abstract: Computer software was developed to predict CANDU fuel channel failure in the event of a total station blackout. The model created successfully predicted the available experimental data.


title: Characterization of protein and DNA interactions of the human DNA repair protein XRCC1

contributor:
Junop, Murray
Biochemistry and Biomedical Sciences

abstract:
DNA single strand break repair and base excision repair are two repair pathways essential for life in humans. XRCC1 is required for repair in both pathways and is believed to act primarily as a scaffold protein for assembly of several other repair factors at the site of damage. In addition to orchestrating the repair event through protein-protein interactions, XRCC1 is thought to make direct contact with DNA; however, the importance of this interaction has not been demonstrated in vivo. Work described here localizes the in vitro DNA binding activity of XRCC1 to a minimal binding region (residues 219-415) encompassing the first BRCT domain (301-415) and an additional 80 residues N-terminal to the BRCT domain. Further analysis reveals that K243, K245, R246, K247, K271, R272, K274 act as key resides for mediating interaction with DNA. Interestingly, although the region N-terminal to the BRCT domain is predicted to lack structure, small angle X-ray scattering experiments demonstrate the presence of structure afforded by a series of proline residues. A XRCC1 DNA binding-deficient mutant is further shown to be deficient in foci formation at sites of single strand breaks demonstrating, for the first time, a direct role for XRCC1 DNA binding activity in vivo.
This work further identifies several compounds that inhibit interaction of XRCC1-Ligase3. Mutations in XRCC1 that disrupt association with Ligase3 have been shown to abolish DNA single strand break repair in G1 phase of cell cycle. Hence, this interaction serves as a potential target for development of compounds able to sensitize cells toward chemotherapeutic agents that function by alkylating DNA. To this end, a ‘magnetic fishing’ assay was developed to monitor XRCC1-Ligase3 interaction and further used to identify compounds that disrupt the interacting complex. Six lead compounds were found to exhibit a dose-dependent response in disrupting XRCC1-Ligase3 interaction. Despite considerable effort to structurally characterize these compounds in complex with both XRCC1 and Ligase3, no compounds could be located in the crystal structures obtained.
Altogether, work presented here enhances understanding of XRCC1 function by establishing a role for DNA binding in repair, and provides useful leads that may be further developed as chemotherapeutic agents and/or probes for studying DNA repair in the single strand and base excision pathways.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Choice Between Stimuli Associated with Different Histories of Reinforcement when Presented Separately

contributor:
Jenkins, H. M.
Psychology

subject: stimuli, histories of reinforcement, color

abstract:
 Four experiments are reported in which choice behavior was examined in the pigeon. An apparatus was used in which each of two adjacent keys could be lit with either a red or a green dot. In each experiment, subjects received trials of fixed length with one color at a time
(single-stimulus training) before receiving trials with both keys lit together (choice test). On choice tests in Exp. 1, 2, and 3, birds pecked at a higher rate to the stimulus in which a higher number of reinforcements had been received per unit time with the stimulus present, but differences between stimuli in reinforcements per session did not reliably affect choice behavior and differences in proportion of trials followed by reinforcement had only weak effects. In Exp. 4, a brief daily choice test was used to evaluate recency effects. It was found that several sessions of experience with only one color were often necessary to reliably shift choice to that color.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: NONLINEAR OPTICAL WAVES IN CATIONIC POLYMERIZATION SYSTEMS: FACILE ROUTES TO 3-D POLYMER AND METALLODIELECTRIC FUNCTIONAL MICROSTRUCTURES

contributor:
Saravanamuttu, Kalaichelvi
Chemistry and Chemical Biology

abstract: Optical nonlinear phenomena occur in a material when the response of a material’s property to the applied optical field depends nonlinearly on the strength of the applied field. Cationic polymerization induced refractive index change (Δn) (nonlinear response of material’s property) in epoxide systems was exploited to elicit modulation instability (MI) and self-trapping (optical nonlinear phenomena) of incoherent light. Demonstration of nonlinear waveforms in cationic polymerization systems revealed that (i) the dynamics of MI can be controlled by polymerization kinetics. This adds a new dimension to the studies of MI in nonlinear systems, as the dynamics of the process so far has been predominantly described by optical parameters such as intensity, wavelength and coherence. Our study shows for the first time that MI occurs only when a balance is struck between photoresponsive time (determined by polymerization rate) and magnitude of Δn (determined by the extent of cross-linking). Thus, it showed that the dynamics of the process can be tuned by polymerization kinetics. Also nonlinear phenomena in cationic systems provide facile routes to robust three dimensional polymer and metallodielectric functional microstructures. (ii) Utilizing the correlation between polymerization kinetics and MI dynamics, thermomechanically stable epoxide-siloxane blend systems were developed for the fabrication of MI induced 3D polymer waveguide microstructures. These blend systems are mechanically robust, thermally stable as well as they satisfy the prerequisites for the occurrence of MI. (iii) Metallodieletric (polymer microstructures embedded with gold and silver nanoparticles) 3D microstructures were fabricated in epoxide-siloxane blend systems by combining in-situ synthesis with MI. (iV) Also in-situ synthesis of gold nanoparticles in epoxide-siloxane matrix was combined with photopolymerization to generate gold nanoparticles fractal aggregates embedded thin films. And these metallodielectric flexible thin films were shown as effective SERS substrates. (V) Optical nonlinearity offered by the photocationic polymerization of epoxide was exploited to show self-trapping of incoherent beam, another nonlinear phenomenon which occurs under similar conditions to MI. Based on self-trapping of incoherent beam in photopolymerizable epoxide system, a new 3D printing technique was developed.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: A Personal Construct Approach to Urban Neighbourhood Cognition

contributor:
Betak, J. F.
Geography

subject: personal construct, urban neighbourhood, cognition

abstract: The importance of neighbourhood identification as part of the overall urban image is outlined. The manner in which individuals cognitively structure neighbourhood is examined along two major lines of enquiry. Firstly, differences in the spatial extent of neighbourhood with which respondents identify, are related to their socio-economic and role profiles. The second section of the study uses the methodology of Personal Construct Theory, in particular, the repertory grid test, to elicit the constructs or attributes which individuals use in deciding that certain segments of the surrounding district are within their cognitive neighbourhood while other segments are felt to be outside. The findings indicate that statements about social class and surrogates for this variable, are the primary discriminator between neighbourhood and non-neighbourhood.

abstract: Thesis

abstract: Master of Arts (MA)


title: On The Mutation Parameter of Ewens Sampling Formula

contributor:
Feng, Shui
Mathematics and Statistics

subject:
statistiscs
mutation rate
Ewens sampling formula

abstract:
Ewens sampling formula is the sampling distribution for a population assumed to follow a one parameter Poisson-Dirichlet distribution, where the parameter  is  fixed. In this project this assumption will be loosened and we will look at the parameter as a function of the sample size. This will result in sampling from a family of Poisson-Dirichlet distributions. Estimators for
this new construction will be tested using two different simulation methods.

abstract: Thesis

abstract: Master of Science (MSc)


title: On Thin Shallow Elastic Shells Over Polygonal Bases

subject: thin shallow, elastic shells, polygonal bases, surface deformation

abstract:
 This thesis proposes to demonstrate, by means of numerieal examples, the applicability of the approximate solution for shallow, spherical, calotte shells enclosing polygonal bases for the purposes of practical design.

 The theoretical solution is based on a collocation
procedure by means of which prescribed boundary conditions are satisfied at discrete boundary points and is derived from the general theory of MUSHTARI and VLASOV in which the transverse shear deformation of the shell is neglected in comparison with its transverse bending and extensional surface deformation.

abstract: Thesis

abstract: Master of Engineering (MEngr)


title: ON-MACHINE MEASUREMENT OF WORKPIECE FORM ERRORS IN ULTRAPRECISION MACHINING

contributor:
Veldhuis, Stephen
Mechanical Engineering

subject: on-machine measurement of workpiece form errors in ultraprecision machining, on machine measurement of workpiece form errors in ultraprecision machining, on machine measurement of work piece form errors in ultraprecision machining, on-machine measurement of work piece form errors in ultraprecision machining, on-machine measurement of workpiece form errors in ultra precision machining, on-machine measurement of work piece form errors in ultra precision machining, on machine measurement of work piece form errors in ultra precision machining, online measurement of work piece form errors in ultraprecision machining, online measurement of workpiece form errors in ultraprecision machining, online measurement of work piece form errors in UPSPDT machining, nanometrology, on-machine measurement of work piece form errors in UPSPDT machining, metrology, on-machine, on machine, nano-metrology, online, offline, measurement, UP-SPDT, UP, UPSPDT, SPDT, ultra-precision, ultraprecision, machining, metrology, surface finish, form error, spatial frequency, work piece, workpiece, production, manufacturing, laser interferometry, lion precision, Lion Precision, capacitance, high resolution, capacitor, machine, vacuum chuck, interferometer, Fiona Gomersall, Gomersall, Veldhuis, Stephen Veldhuis, optics, photonics, ultraprecision single point diamond turning, diamond turning, differential, differential screw, high resolution sensor, sensor, FFT, fast fourier transform, derivative, signal processing, error band, resolution, data acquisition, micro-machining, micromachining, precision machining, precision, machine system, charge, static charge, diamond, diamond tool, indicator, electronic indicator, tactile probe, touch probe, engineering, mechanical, mechanical engineering, LVDT, signal conditioning, ICS, bandwidth, capacitance system interface, optical sensor, DAQ, sampling, high spatial frequency, low spatial frequency, optical components, vibration, spindle vibration, dominant frequency, machine vibration, mechanical vibration, phase, phase lag, ogive, kinematic error, abbe error, centering, linear regression, deformation, residual stress, filtering, moving average filter, moving average, rolling average, box average, running average, normal distribution, Gaussian distribution, standard deviation, filters, low pass filter, high pass filter, frequency response, filter, electronic noise, noise, dc component, cutting plane, lathe, turning, fixture, workpiece fixture, work piece fixture, sampling error, bin resolution, bandpass, frequency spectrum, measurement system, measurement error, kinematics, online surface finish measurement, on machine surface finish measurement, online surface form error measurement, on machine surface form error measurement, on machine measurement, online measurement, quality control, automated quality control, ultraprecision surface finish measurement, ultraprecision form error measurement, precision surface finish measurement, precision form error measurement, workholding, work holding deformation, data processing, nanopositioning, nano-positioning tools, micro-positioning tools, micro positioning tools, micromachining fixtures, micromachining positional errors, measurement of low to mid-spatial frequencies, measurement of low spatial frequencies, new tools in nanometrology industry, new tools in nanometrology production, new tools in nanometrology manufacturing, new techniques for surface finish measurement, new techniques for on machine measurement, new tools for surface finish measurement, new techniques for ultraprecision surface finish measurement, ultraprecision surface finish measurement, measuring ultraprecision surfaces, measuring ultra precision surfaces, tools for measuring ultraprecision surface finish, tools for measuring ultraprecision form error, measuring ultraprecision form error, form error measurements in ultraprecision single point diamond turning

abstract:
Ultraprecision single point diamond turning is required to produce parts with sub-nanometer surface roughness and sub-micrometer surface profiles tolerances.  These parts have applications in the optics industry, where tight form accuracy is required while achieving high surface finish quality.  Generally, parts can be polished to achieve the desired finish, but then the form accuracy can easily be lost in the process rendering the part unusable.
Currently, most mid to low spatial frequency surface finish errors are inspected offline.  This is done by physically removing the workpiece from the machining fixture and mounting the part in a laser interferometer.  This action introduces errors in itself through minute differences in the support conditions of the over constrained part on a machine as compared to the mounting conditions used for part measurement.  Once removed, the fixture induced stresses and the part’s internal residual stresses relax and change the shape of the generally thin parts machined in these applications.  Thereby, the offline inspection provides an erroneous description of the performance of the machine.
This research explores the use of a single, high resolution, capacitance sensor to quickly and qualitatively measure the low to mid spatial frequencies on the workpiece surface, while it is mounted in a fixture on a standard ultraprecision single point diamond turning machine after a standard facing operation.  Following initial testing, a strong qualitative correlation exists between the surface profiling on a standard offline system and this online measuring system.  Despite environmental effects and the effects of the machine on the measurement system, the capacitive system with some modifications and awareness of its measurement method is a viable option for measuring mid to low spatial frequencies on a workpiece surface mounted on an ultraprecision machine with a resolution of 1nm with an error band of ±5nm with a 20kHz bandwidth.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Violence by Any Other Name: Exploring the Use of Moral Panic in the Pathologization of Refugees Using Critical Discourse Analysis

title: Violence by Any Other Name

contributor:
Joseph, Ameil
Social Work

subject:
refugees
moral panic
mental health
media
critical discourse
deterrence

abstract:
SARAH ADJEKUM B.A., B.S.W.
A Research Project
Submitted to the School of Social Work
in Partial Fulfillment of the Requirements
for the Degree
Master of Social Work
McMaster University 2016

abstract: As observed with the ongoing migrant crises, media coverage of refugee and asylum seekers connects the concepts of mental health and trauma to their experiences. The resulting discourse around refugees pathologizes the refugee identity and simultaneously obscures the violence that necessitates their departure from their home countries. As refugee discourse incorporates discourses of mental health, it also legitimizes nation state’s practice social control towards these populations through detention. As the utilization of technologies of securitization is normalized, detention has become increasingly accepted as a response to humanitarian crises. Past research on detention has consistently demonstrated the harmful effects it has on children, adults, and especially individuals with symptoms of mental illness. In particular, research drawing on trauma and mental health discourse has been effective in bringing attention to the counterproductive outcomes of detention. This paper is concerned with the employment of discourses of mental health and trauma by mainstream media as they pertain to the treatment of migrants in detention in Canada. It explores the media’s role in the re(creation) of refugee discourse and purveyors of racial ideology that problematizes people of colour and demands state intervention in the form of mental health aid.  Using critical discourse analysis, it contrasted mainstream media coverage of four major publications on detention. This study finds prevalent use of mental health discourse and little mention of violence in several online publications. It also finds that recommendations made in the articles emphasized micro and mezzo focused changes that are unable to challenge federal policy that enables securitization. Nor is it capable of addressing the forms of violence inherent to the mental health system. As such, this paper makes recommendations for a critical examination of refugee and immigration policy that takes into account the states’ participation in the creation of refugee crises.

abstract: Thesis

abstract: Master of Social Work (MSW)


title: The Impact of Drop-In Centres on the Health of Street Children in New Delhi, India

contributor: Clinical Epidemiology/Clinical Epidemiology & Biostatistics

subject:
Street child
health
drop-in centre

abstract:
Objectives: To understand how and to what extent drop-in centres are associated with the physical and mental health and substance use status of street children in New Delhi.
Methods: In a qualitative study, I interviewed 23 street children and two drop-in centre staff members in New Delhi. Subsequently, I conducted a cross-sectional study with 69 street children who attended centres and 65 street children who did not visit centres. I used questionnaires to assess their physical and mental health and substance use.
Findings: Participants believed that because street children regularly visited drop-in centres, their health outcomes improved. Street children participated in drop-in services because staff members were nonjudgmental, they were free to be a child, their daily struggles were lessened, they received protection, they were given moral direction and they had an opportunity for a better life. However, children continued to live on the streets because street life had become normal. Quantitative findings showed that street children who visited centres had better physical and mental health outcomes and engaged in less substance use than street children who did not visit centres (p<0.01). For every month of attendance, street children experienced 2.1% (95% CI 0% to 4.1%, p=0.05) fewer ill health outcomes per month and used 4.6% (95% CI 1.3% to 8%, p=0.01) fewer substances. Street children were also less likely to have been a current substance user than a never substance user for every additional month at a center (OR: 0.79, 95% CI: 0.66 to 0.96, p=0.02). Duration of attendance was not significant in predicting mental health.
Conclusion: According to participants, drop-in centres positively influence the physical and mental health and substance use status of street children by providing services in an environment tailored for them. Quantitatively, centres may improve the physical health of street children and reduce their substance use.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: Street children in low- and middle-income countries (LMICs) experience poor health. Drop-in centres are one of most common interventions for street children; however, they have not been evaluated in LMICs. I aimed to understand how and how much drop-in centres influence the physical and mental health and substance use status of street children in New Delhi, India. Street children and drop-in centre staff members were interviewed about how they believed centres influenced the health and substance use habits of street children. Participants felt that drop-in centres improve children’s health and substance use habits because the centres provided services in an environment tailored for street children. I also used questionnaires to evaluate the impact of drop-in centre attendance on 69 street children who regularly came to centres and 65 street children who did not come to centres. Quantitatively, centres may improve the physical health and substance use status of street children.


title: Econometric Analysis of Firm-level Production Data

contributor:
Racine, Jeffrey
Economics

subject: stochastic frontier

subject: robust frontier

subject: firm-level productivity

subject: semiparametric and nonparametric estimation

subject: production function

abstract: In this dissertation, I explore a variety of methods for the econometric analysis of firm-level production data. Three distinct approaches are considered, namely i) proxy variable methods of controlling for unobservable productivity, ii) data envelopment techniques for estimating the boundary of a production set, and iii) stochastic frontier methods for estimating the productive inefficiency of firms. Much of the focus is on semiparametric and nonparametric estimators that allow for a highly flexible specification of the function that relates input combinations to output quantities.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Studies on Astrophysical Nuclides Far From Stability with Numerical Simulations and Systematics

contributor:
Chen, Alan
Physics and Astronomy

subject: Nuclear Astrophysics

abstract:
Explosive events in our universe provide an environment where rare nucleosynthesis events can occur. Understanding the mechanisms and processes during these events is integral to understanding the relative abundances of the elements in our universe. The rapid neutron capture process or r-process is thought to be responsible for producing approximately half of the heavy elements in our universe. A critical input in the calculation of r-process nucleosynthesis is the beta-delayed neutron (B DN) emission probability, Pn. However
theoretical calcuations of Pn have not been successful in reproducing experimental values. A semi-empirical formula using systematics can be adopted, which can give an approximate Pn value for unmeasured precursors. To complete this, we carried out a comprehensive evaluation of Pn and half life,T1=2 values from literature, which we present in this work in a table of recommended values for the range Z=30-40,49,50. Two methods of identifying systematics in
neutron emission probability Pn (McCutchan et al. 2012),(Kratz,Herrmann, 1988) are compared using the evaluated values, wherein the McCutchan et al. method was signifi cantly more accurate than the Kratz-Herrmann method, and especially so in the lower Q regions. In this work we also explore classical novae and present a sensitivity study on classical nova nucleosynthesis endpoint nuclei. The reaction rates of 36Ar,37Ar and 40K were of particular
interest as they showed the largest impact on the fi nal abundances.

abstract: Thesis

abstract: Master of Science (MSc)