title: INTIMATE PARTNER VIOLENCE (IPV) IN PUNE, INDIA: A COMPARISON OF MALE AND FEMALE ATTITUDES, AND THE USE OF WAST TO MEASURE IPV AMONG INDIAN MEN

contributor:
Bhandari, Mohit
Global Health

subject:
Intimate partner violence
IPV
Domestic Violence
India
WAST
IPV attitudes
Male victims of IPV

abstract:
Intimate partner violence (IPV) includes physical, emotional, psychological and sexual abuse. The impact of IPV has become increasingly accepted as a significant public health problem worldwide. This manuscript thesis has two chapters which attempts to address the current gaps in IPV research in India.
The first chapter compares people’s attitudes about IPV based on their gender, age, income and exposure to IPV. In order to better understand and compare men and women’s attitudes about IPV, 204 self-administered surveys were collected from the in- and out-patient clinics of the Sancheti Institute for Othopedics and Rehabilitation (SIOR), a hospital in Pune, India.  The results of these surveys showed that men and older generations were more likely to agree that wife-slapping was a justified response to least one of the presented scenarios, and to support normatively prescribed rights of Indian husbands to have excessive power in a marriage. Income level and experience being a victim of IPV were not associated with attitudes towards IPV or husbands’ rights.
The second chapter explores the use of the Woman’s Abuse Screening Tool (WAST) in a sample of 62 males. Results from the WAST indicated a 16% IPV prevalence rate.
These two papers shed light on different aspects of IPV. Results from the first paper suggest that men and older generations should be targeted for educational initiatives aimed at reducing IPV. The second paper provides a much-needed estimation of IPV prevalence among Indian males. Together, these findings help close existing gaps in the literature regarding IPV in India.

abstract: Thesis

abstract: Master of Science (MSc)


title: Carbon Nanotube Thin Films as Flexible Substrates for the Support of Inorganic Nanostructures

contributor:
Adronov, Alex
Chemistry

subject:
carbon nanotube
nanotechnology
scaffold
thin film
inorganic nanostructure
nanowire

abstract:
Carbon nanotubes (CNTs) are arguably the most widely studied material within the field of nanotechnology. The impressive physical and electronic properties of these materials have led to their investigation in a diverse range of applications. In recent years, the deposition of inorganic nanoparticles upon the surface of CNTs has received much attention. Research within this field has been driven by the desire to develop new composite materials exhibiting novel electronic, optical, and catalytic properties. In addition to the decoration of individual nanotubes, several groups have also investigated the use of CNT thin films as scaffolds for the assembly of inorganic nanostructures as well as other secondary components, including polymers and biomaterials. Nanotube films exhibit a number of physical properties that make them suitable for such
applications, displaying impressive electrical conductivity, flexibility, and thermal stability while also possessing a high surface area upon which chemical modification can be conducted.

This thesis presents work that demonstrates the potential of CNT thin films as flexible conductive scaffolds for the support of a variety of inorganic nanostructures. Procedures are described for the preparation of SWNT -Au nanoparticle composite films that, as subsequently demonstrated, are suitable substrates for the growth of III-V semiconductor nanowires using gas-source molecular beam epitaxy. At the time of writing, the majority of published research within this field focused upon the preparation of SWNT composite films containing spherical metallic or semiconductor nanoparticles. In contrast, the growth of semiconductor nanowires upon nanotube thin films had not been explored. The work described in this thesis therefore represents the development of a novel composite material that combines the flexibility of CNT films with the unique optoeletronic properties exhibited by semiconductor nanowires. The development of functional electronic devices incorporating these materials is also discussed, as is the extension of the methods developed to investigate novel composite materials that combine other inorganic nanostructures with carbon based substrates.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Molecular Basis of Lipid Acyl Chain Selection by the Integral Outer Membrane Phospholipid:Lipid A Palmitoyltransferase PagP from Escherichia Coli

contributor:
Bishop, Russell E.
Biochemistry

subject:
lipid metabolism
PagP
Escherichia coli
β-barrel
substrate recognition
substrate binding
acyl-chain
lipid diffusion

abstract: The role of membrane-intrinsic enzymes of lipid metabolism in complex biological processes is being realized through comprehensive structure function studies. Detailed analysis of substrate-enzyme interactions occurring within the restrictive membrane environment has proved to be exceedingly challenging. Using detergent micelles, we describe a detailed model for substrate recognition and binding by the outer-membrane intrinsic enzyme PagP from Escherichia coli. PagP is an 8-stranded antiparallel β-barrel that transfers a palmitoyl group from a phospholipid molecule to lipid A, the endotoxin component of lipopolysaccharide. This simple modification provides bacterial resistance to host antimicrobial peptides and attenuates the inflammatory response signalled through the host toll-like receptor 4 pathway. We describe a molecular embrasure and a crenel, which display weakened transmembrane β-strand hydrogen bonding, to provide site-specific routes for lateral entry of substrates into the PagP active site. A Tyr147 localized to the L4 loop gates the entry of the phospholipid substrate through the crenel, while lipid A enters via the embrasure. The side chains of the catalytic residues that are located in the extracellular loops point towards the central axis of the enzyme, directly above the active site. An acyl-chain binding pocket known as the hydrocarbon ruler is buried within the transmembrane β-barrel structure, and is optimized to accommodate a 16-carbon saturated palmitate chain. The hydrocarbon ruler, therefore, accounts for PagP's stringent selectivity for a palmitate chain. Substituting Gly88 lining the floor of the hydrocarbon ruler with residues possessing linear, unbranched, aliphatic side chains changes the selectivity of PagP to utilize shorter acyl chains. The serendipitous discovery of an exciton interaction between Trp66 and Tyr26 at the floor of the hydrocarbon ruler provides an intrinsic spectroscopic probe to monitor the methylene unit acyl-chain resolution of PagP. A compromised acyl chain resolution of the Gly88Cys mutant is attributed to an unexpected decrease of the Cys sulfhydryl group pKa within the β-barrel interior, resulting in a burying of a charged thiolate within the PagP core. The structural perturbation associated with the Cys thiolate extinguishes the exciton and expands the acyl-chain selectivity. These molecular details of lateral lipid diffusion and acyl-chain selection provide the first such example for any membrane-intrinsic enzyme of lipid metabolism.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Design, Fabrication and Analysis of Broadly Tunable Asymmetric Multiple Quantum Well Coupled Cavity Diode Lasers

contributor:
Cassidy, Daniel T.
Engineering Physics

subject:
coupled cavity semiconductor laser
asymmetric multiple quantum well
optical coherence technology
wavelength switching

abstract:
A detailed analysis of coupled cavity semiconductor lasers with asymmetric multiple quantum well (AMQW) active regions is presented in this thesis. The analysis involved design, fabrication, characterization, and simulation of these devices. Although the coupled cavity devices can be multi sectioned, the devices discussed in this thesis are two sectioned.

 A below threshold model for an AMQW coupled cavity device is developed. Non-linear fits of the below threshold spectral data to that obtained from the model were used to extract optimized device parameters. These fits helped to create an understanding of the operation of the devices and paved the way for improved device performance. Optimized device parameters obtained from the below threshold model were later used as input parameters in the development of an above threshold model. This model verified the wavelength selection mechanism employed by coupled cavity diode lasers and predicted the longitudinal modes for sets of injection currents.

 Optical coherence tomography (OCT) is an application where much interest has recently been drawn. The coupled cavity devices fabricated in this work applied with proper modulation of the injection currents and followed by subsequent time averaging have demonstrated short coherence length (-15 μm) and can be an excellent source for synthesized OCT. Rapid wavelength switching (-70 ns, the measurement was limited by detector response time) over the whole range has also been experimentally shown. Because of the high speed (relative to mechanical) wavelength switching ability, AMQW coupled cavity devices have the potential for applications requiring real time measurements including real time synthesized OCT.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Protein-Resistant Polyurethane Prepared by Surface-Initiated Atom Transfer Radical Polymerization of Water-Soluble Polymers

contributor:
Zhu, Shiping
Brash, John L.
Chemical Engineering

subject: water-soluble polymer

subject: protein-resistant polyurethane

subject: protein resistance

subject: adsorption

subject: OEGMA

abstract:
This work focused on grafting water-soluble polymers with well-controlled properties such as tuneable polymer chain length and high graft density to improve the biocompatibility of polymer surfaces via surface-initiated atom transfer radical polymerization (s-ATRP); and on gaining improved fundamental understanding of the mechanisms and factors (e.g., graft chain length and surface density of monomer units) in protein resistance of the water-soluble grafts.

Protein-resistant polyurethane (PU) surfaces were prepared by grafting watersoluble
polymers including poly(oligo(ethylene glycol) methacrylate) (poly(OEGMA))
and poly(l-methacryloyloxyethyl phosphorylcholine) (poly(MPC)) via s-ATRP. A typical three-step procedure was used in the ATRP grafting. First, the substrate surface was treated in an oxygen plasma and reactive sites (-OH and -OOH) were formed upon exposure to air. Second, the substrate surface was immersed in 2-bromoisobutyryl bromide (BffiB)-toluene solution to form a layer of ATRP initiator. Finally, target polymer was grafted from the initiator-immobilized surface by s-ATRP with Cu(I)Br/2bpy complex as catalyst. The graft chain length was adjusted by varying the molar ratio of monomer to sacrificial initiator in solution. The modified PU surfaces were
characterized by water contact angle, X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM).

Protein adsorption experiments were carried out to evaluate the protein resistance of the surfaces. Adsorption from single and binary protein solutions as well as
from plasma decreased significantly after poly(OEGMA) grafting, and decreased with increasing poly(OEGMA) main chain length. Fibrinogen (Fg) adsorption on the most resistant surfaces (chain length 200 units) was in the range of 3-33 ng/cm^2, representing a reduction of more than 96% compared to the control surfaces.

OEGMA monomers with three different molecular weights (MW 300, 475, 1100 g/mol) were used to achieve different side chain lengths of poly(OEGMA). Fibrinogen (Fg) and lysozyme (Lys) were used as model proteins in adsorption experiments. The effects of side chain length as well as main chain length were then
investigated. It was found that adsorption to the poly(OEGMA)-grafted PU (PU/PO) surfaces was protein size dependent. Resistance was greater for the larger protein. For grafts of a given side chain length, the adsorption of both proteins decreased with increasing polymer main chain length. For a given main chain length, the adsorption of Fg, the larger protein, was independent of side chain length. Surprisingly, however, Lys (the smaller protein) adsorption increased with increasing side chain length. A reasonable explanation is that graft main chain density decreased as monomer size and footprint on the surface increased. Protein size-based discrimination suggests that the chain density was lower than required to form layers in the "brush" regime in which protein size is expected to have little effect on protein adsorption.

In order to achieve high surface densities of ethylene oxide (EO) units, we used a sequential double grafting approach whereby the surface was grafted first with poly(2-hydroxyethyl methacrylate) (HEMA) by s-ATRP. OEGMA grafts were then grown from
the hydroxyl groups on HEMA chains by a second ATRP. The effect of EO density on protein-resistant properties was then investigated. Protein adsorption on the sequentiallygrafted poly(HEMA)-poly(OEGMA) surfaces (PU/PH/PO) was not only significantly lower than on the unmodified PU as expected, but also much lower than on the PU/PO surfaces with the same poly(OEGMA) chain length. Moreover, protein adsorption decreased with increasing EO density for these grafts. On the PU/PH/PO surface with a poly(OEGMA) chain length of 100, the adsorption of Ls and Fg were reduced by ~98% and >99%, respectively, compared to the unmodified PU. Binary protein adsorption experiments showed that suppression of protein adsorption on the PU/PH/PO surfaces was essentially independent of protein size. The double-grafted OEG layers resisted both proteins equally.

The general applicability of this approach which combines oxygen plasma treatment and ATRP grafting was also studied. Various kinds of polymers such as PU, silicone hydrogel, and polydimethylsiloxane (PDMS) were chosen as substrates. Poly(MPC) grafts with different chain lengths were achieved by the three-step ATRPgrafting procedure. It was found that protein adsorption levels on the poly(MPC) grafts were significantly lower than on the respective unmodified surfaces. Protein adsorption decreased with increasing poly(MPC) chain length. Among the surfaces investigated, PU/MPC showed the highest protein resistance for a given chain length.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: VQA: Self-Regulation as Identity Construction in the Ontario Wine Industry

contributor:
Satzewich, Vic
Sociology

subject:
Ontario wine industry
Vinters Quality Alliance
globalization
Wine Authority
identity
grape

abstract: This thesis investigates the intersection of a local place with the forces of globalization which destabilized existing social, cultural and economic sources of meaning and identity. The research setting is the Ontario wine industry, which appeared to be on the verge of collapse in the 1980s because of changing consumer tastes, an adverse GATT trade ruling and the effects of the Canada-US Free Trade Agreement. The research draws on semi-structured interviews with wine industry participants who were instrumental in the construction of the new identity and on documentary research including corporate documents, public reports and media articles to trace the evolution of the VQA from a project identity to a legitimizing identity. The introduction of voluntary industry self-regulation through the Vintners Quality Alliance (VQA), an appellation of origin system, was a local response to the inclusion/exclusion logic inherent in globalization. A small sector of the industry mobilized to construct an alternative collective identity, not of resistance to global forces, but of accommodation to them. In a political expression of their collective interests, cottage wineries operating on the margins of the industry, took advantage of existing resources in the local and international domain to craft an identity for quality wines based on 100% local grapes. Institutionalizing the new identity meant negotiating ongoing relationships of power and influence to become a political actor with the authority to shape the content and meaning of a this identity. The process led to transformation of the industry and local place, and acquired legitimacy through provincial legislation that appointed the VQA as the Wine Authority. This conferred on Vintners Quality Alliance Ontario the powers of the state to enforce industry compliance with the standards which comprise the identity.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Design and Implementation of a Lithium-ion Cell Tester Capable of Obtaining High Frequency Characteristics

contributor:
Habibi, Saeid
Mechanical Engineering

subject:
Battery testing
Lithium-ion
Battery modeling
EIS
battery

abstract: The field of energy storage has improved drastically within the last two decades. Batteries of various chemistries have been relied on to provide energy for numerous portable electronic devices. Lithium-ion cells, when compared to other chemistries have been known to provide outstanding energy-to-weight ratios and exhibit low self-discharge when not in use [1]. The aforementioned benefits in conjunction with decreasing costs have made lithium-ion cells an exceptional choice for use in electrical vehicles (EVs). Battery Management Systems (BMS) in EVs are responsible for providing estimates for values that are indicative of the battery pack’s present operating condition.  The current operating condition could be described by State of Charge, power fade, capacity fade and various other parameters [2]. Importantly, it is essential for the estimation technique to adjust to fluctuating cell characteristics as the cell ages, in pursuance of having available accurate estimates for the life time of the pack. In order for the estimation technique to properly estimate the desired quantities, a mathematical model capable of capturing cell dynamics is desired. There are various proposed methods recommended for mathematically modeling a cell, namely equivalent Circuit modeling, electro-chemical modeling and impedance spectroscopy. Consequently, in order to ensure mathematical models are accurate and further to have the ability to compare the proposed models, it is essential to have available data gathered from a given cell at specific operating conditions. This Master’s thesis outlines the development of a lithium-ion cell tester that is capable of controlling, monitoring and recording parameters such as current, voltage and temperature. The Dual capability of obtaining data from standardized cell tests as well as high frequency cell tests is fascinating and intriguing. As this capability holds the possibility of reducing cost otherwise spent on man hours and equipment which are both paramount in any industrially automated process.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Daily Targeted Evidence Reports for Orthopaedic Surgeons: A Mixed Methods Study in India

contributor:
Bhandari, Mohit
Busse, Jason
Global Health

subject:
Evidence-Based Medicine
Evidence-Based Orthopaedics
Knowledge Dissemination Portals
Knowledge Translation
Mixed Methods
Pre-Appraised Resources
Qualitative Study
Residency Training

abstract:
Background: There is limited research on how web-based, point-of-care, evidence-based medicine (EBM) tools, such as evidence summaries, are being implemented and used in developing countries.
Objectives: To investigate accessibility, use, and impact of an online EBM knowledge dissemination portal in orthopaedic surgery. To explore whether receiving daily targeted evidence summaries results in more frequent use of an EBM tool compared with receiving general weekly reports. To identify and explain the barriers and benefits of a point-of-care resource in the Indian context.
Methods: Forty-four orthopaedic surgeons in Pune, India, were provided free access to OrthoEvidence (OE), a for-profit, online EBM knowledge dissemination portal. Participants were subsequently randomized to an Intervention group receiving daily targeted evidence summaries or a Control group receiving general weekly summaries. This study employed an explanatory sequential mixed methods design that incorporated two questionnaires, OE usage data, and semi-structured interviews to gain insight into the surgeons’ usage, perceptions and impact of OE.
Results: There were no observable differences in OE usage between the Intervention and Control groups. OE was deemed to be comprehensive, practical, useful, and applicable to clinical practice by the majority of surgeons. The exit survey data revealed no differences between groups’ perceptions of the OE tool. Semi-structured interviews revealed barriers to keeping up with evidence that included limited access to relevant medical literature (limited internet connection, lack of time, minimal access to medical journals) and limited incentive to keep up with it (limited decision-making powers for residents, textbook-based residency curriculum, lack of research methods knowledge, limited context-specific research). Changing trauma practices at the hospital were noted following the intervention.
Recommendations: The practice of EBM and the use of point-of-care tools in India can be promoted by investing in adequate electronic infrastructure (improvements to internet access) and by integrating EBM into training programs and surgical cultures.

abstract: Thesis

abstract: Master of Science (MSc)


title: Three-Phase 24/16 Switched Reluctance Machine for Hybrid Electric Powertrains: Design and Optimization

contributor:
Emadi, Ali
Mechanical Engineering

abstract:
This thesis studies the method of optimizations of conduction angles for switched reluctance motors (SRMs) and presents an optimization and design of a three-phase 24/16 SRM used in the powertrain of hybrid electric vehicles (HEVs).
The electrified powertrains, especially the power-split powertrain used in the Toyota Prius, are studied in this thesis. Different types of electric machines used as traction motors in HEV are compared. Results show that SRMs can be an alternative to replace interior permanent magnet synchronous machines (IPMSMs) commonly used as the traction motors in HEVs and EVs. The mechanism, operation, and electromagnetic energy, and control of SRMs are presented.
Studies show that conduction angles affect SRMs’ performances, such as output torque, torque ripple, and efficiency. In this thesis, a fast optimization-based procedure for automatically characterizing SRM performances is proposed. Within the procedure, four optimization problems, including two single-objective and two multi-objective, are formulated in order to optimize the conduction angles for SRMs. The objectives used in these optimization problems are aimed towards maximizing average output torque, maximizing the ratio of average torque to RMS value of phase current, and maximizing RMS value of net torque ripple. One multi-objective optimization, which employs maximizing average output torque, and maximizing RMS value of net torque ripple as the objectives, is chosen in the optimization of conduction angles for priority operating points and over the entire operating range, because this method balances output torque and torque ripple. It also has highly competitive performances in motor efficiency. The procedure is then used to obtain the motor’s performances, such as torque-speed profile, loss map, and efficiency. Experimental results from a 12/8 SRM at three operating points are carried out to verify the results from the procedure.
This procedure is used in the design of a 60 kW three-phase 24/16 SRM as well. The motor is targeted to replace an IPMSM as the traction motor in the HEV powertrain of the 2010 Toyota Prius. In this thesis, the optimized results for motor designs with different stator pole height, stator taper angle, rotor pole arc angle, and stator pole shoe shape, are presented and compared in terms of output torque, RMS value of phase current, normalized torque ripple, and optimized conduction angle. The finalized motor design is characterized using the optimized turn-on and turn-off angle lookup table obtained from the same optimization. The motor performances, such as torque-speed profile, torque ripple, copper losses, core losses, etc., over the entire operating range are studied. At the end of this thesis, the sub-assemblies of the frame, the rotor-shaft, and stator-winding, are designed and discussed. Thermal analyses on the finalized motor are also studied. The SRM’s torque-speed profile matches that of the IPMSM used in the 2010 Toyota Prius. The SRM has competitive motor efficiency over the entire operating range when compared with the Prius motor.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Successes and Pitfalls in Running a Small Program MMI

contributor:
Reiter, Harold
Health Science Education

subject: MMI, multiple-mini interviews, candidate selection, admission selection

abstract:
Purpose: Academic programs are faced with the important task of selecting health professional students who not only possess necessary cognitive abilities to perform their future job, but also have valuable personal/professional characteristics to draw upon in the provision of quality patient care. There is therefore "widespread agreement that it is desirable to broaden the scope of assessment beyond academic achievement" (Eva, Reiter, Trinh, Wasi, Rosenfeld, Norman, 2009, p.768) in candidate selection. The Child Life Studies Program at McMaster University used a 4-station multiple mini-interview (MMI) as part of the admission selection process. This study sought to determine the feasibility, degree of acceptability and reliability of this 4-station MMI design, and if there were any predictors of candidate's performance on the MMI.
Methods: A group of 35 applicants in 2014, and 40 applicants in 2015 screened through admission procedures participated in a 4-station MMI. Each station was 15 minutes in length with 5 minutes for scoring each candidate. Anonymous stakeholder surveys were used in 2015 to assess participant and interviewer's perceptions and acceptability of the MMI in applicant selection. Generalizability coefficients were calculated to determine reliability. In addition, candidate's experience in healthcare, professional work experience, experience with children with disabilities, and previous child life course work (or lack thereof) were analyzed through independent t-tests to report any relationship with candidate's performance on the MMI. A one-way ANOVA was also completed to report any relationship between candidate's undergraduate degree type and his/her MMI performance.
Results: The 4-station MMI was found to be feasible for a small program with a marked increase found in the number of candidates interviewed in a shorter period of time. It was also found to be highly acceptable among candidates and faculty. However, this studies' findings did not show statistically significant differences in MMI performance based on identified predictors, or undergraduate degree type.  The reliability of the 4-station design in 2014 was G=0.718, however, was only G=0.089 in 2015, far lower than expected based on the prior year’s G Coefficient. The potential pitfalls in running a small program MMI are discussed with specific suggestions and modifications provided to enhance reliability of candidate selections across professions.

abstract: Thesis

abstract: Master of Science (MSc)


title: Special Block-Colourings of Steiner 2-Designs

contributor:
Rosa, Alex
Mathematics

subject: block, colourings, steiner, designs, special, pair, system

abstract:
 Let t, k, v be three positive integers such that 2 ≤ t < k ≤ v. A Steiner system S(t, k, v) is a pair (V, B) where |V| = v and B is a collection of k-subsets of V, called blocks, such that every t-subset of V occurs in exactly one block in B. When t = 2, the Steiner system S(2, k, v) is sometimes called a Steiner 2-design.

 Given a Steiner 2-design, S = (V, B), with general block size k, a block-colouring of S is a mapping ¢ : B ---> C, where C is a set of colours. If |C| = n, then ¢ is an n-block-colouring. In this thesis we focus on block-colourings for Steiner 2-designs with k = 4 with some results for general block size k.

 In particular, we present known results for S(2, 4, v)s and the classical chromatic index. A classical block-colouring is a block-colouring in which any two blocks containing a common element have different colours. The smallest number of colours needed in a classical block-colouring of a design S = (V, B), denoted by x'(S), is the classical chromatic index.

 We also discuss n-block-colourings of type π, where π = ( π1, π2, ... , πs ) is a partition of the replication number r = v-1/k-1 for a Steiner system S(2,k,v). In particular, we focus on 8(2,4,v)s and the partitions (2, 1, 1, ... , 1), (3, 1, 1 ... , 1), and partitions of the form π = (π1, π2, ... , πs), where |πj -πil ≤ 1 for all 1 ≤ i < j ≤ s. These latter partitions are called equitable partitions and the corresponding block-colourings are called equitable block-colourings.

 Finally, we present results on the T-chromatic index for S(2, 4, v )s for various configurations T. The T-chromatic index for a Steiner system S(2, k, v), S, is the minimum number of colours needed to colour the blocks of S such that there are no monochromatic copies of T. In particular, we focus on configurations containing 2 lines and configurations containing 3 lines for both S(2, 4, v)s and general S(2, k, v)s.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Development of a Thick Gas Electron Multiplier Detector for Microdosimetry

contributor:
Byun, Soo-Hyun
Medical Physics

subject: thick, gas, electron, multiplier, microdosimetry, diameter, volume, data

abstract: In experimental microdosimetry one of the goals is to measure the absorbed dose in microscopic volumes of tissue. The traditional spherical tissue-equivalent proportional counter (TEPC) is the most common detector currently used for microdosimetry. A new microdosimetric detector based on a thick gas electron multiplier (THGEM) was developed. To investigate the feasibility of the THGEM type detector for microdosimetry, a prototype detector was designed and manufactured. The THGEM detector is robust, easy to manufacture and is cost effective. The THGEM foil is composed of a thin FR4-epoxy insulator coated with copper on both sides. The THGEM contains 32 holes each with a diameter of 0.35 mm and pitch of 0.64 mm. The sensitive volume of the detector is a right cylinder with a diameter of ~5 mm and height of ~5 mm and is located in the center of the detector. Systematic tests were conducted at the McMaster Accelerator Laboratory to investigate its overall performance. A neutron-gamma ray radiation field was generated using the 7Li(p,n) reaction. The detector was operated at low bias voltages initially to test the stability and then the relative multiplication gain was measured as a function of the operating high voltage. The detector performance was observed with different THGEM insulator thicknesses ranging from 0.12 mm to 1.48 mm. The multiplication gain was assessed and both neutron and gamma-ray radiation was detected by the THGEM detector. The spectra obtained with the THGEM detector were analyzed and compared to the data collected with the standard spherical TEPC. The investigations provided information about the THGEM detector operation for microdosimetry and the THGEM microdosimetric spectra observed are comparable to the standard TEPC data.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Vibration Analysis & Vibrating Screens: Theory & Practice

contributor:
von Mohrenschildt, Martin
Software Engineering

subject: vibration, screens, theory, practice, detection, frequency, sensors

abstract:
 Vibration Analysis (VA) is a key technique used for maintenance and fault detection of vibrating machinery. The purpose of maintenance is to analyze how well the machinery is operating within its target parameters, while fault detection is done to diagnose and locate a fault that might be developing on the machinery.

 If we consider s(n) to be the true signal from a rotating system and e(n) to be the additive noise corrupting the signal, then the observed signal is x(n) = s(n) + e(n). If s(n) is composed of a main driving frequency sm(n) and summed fault frequencies sf(n), then fault detection is the study of sf(n). In fault detection, we eliminate e(n) as much as possible so that sf(n) can be isolated and studied.

 This thesis presents a technique based on cross-correlation, utilizing a network
of sensors, to eliminate e(n) from the measurements, preserving just the correlated
frequency content. This is extended to provide a means of localizing the source of
the frequency content, based on the relative strengths of the members of the complete
set of cross-correlations between all sensors. This technique has been shown to be able to extract a signal buried by noise, in situations where the traditional FFT fails.

 To enable this, a new VA system has been developed. This introduces new wireless vibration sensors as well as a data capture unit capable of providing real-time VA data to technicians. The system can simultaneously capture data from eight sensors, so the data can be used not only for traditional VA techniques, but also in conjunction with the cross-correlation technique described above. This system is now commercially available and in use by dozens of technicians around the world.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: The Dialectics of Middleness: Towards a Political Ontology of Centrism

contributor:
Szeman, Imre
English and Cultural Studies

subject: dialectics, middleness, political, ontology, centrism, global

abstract:
 This dissertation explores the recent history and politics of the formation of the center or middle as the sovereign horizon of contemporary political practice and history. The political center has typically been imagined as the space between the two poles of Left and Right. Rather than beginning with an assumption of the political center's absolute relativity-a history absorbed by infinitely contingent contexts-this thesis understands centrism as itself a political position: a plural, yet relatively stable complex of meanings in urgent need of problematization. Guided methodologically by the work of Michel Foucault and Frederic Jameson, the thesis grounds this analysis in a reading of The Economist magazine between the years 1950-2007. A self-identified advocate of the "extreme center", the magazine functions as a primary archive through which to document shifts in the constitution of an historically-specific centrism, a political position with significant global traces and consequences.

 In the Introduction the basic theoretical coordinates of the center as a metaphor, concept and political fantasy are unpacked against the backdrop of a broader diagnostics of the present. Chapter 1 addresses itself to the Keynesian centrism prevalent in the years immediately following the war in Britain, one characterized primarily by ideas about balance, consensus, and moderation. Chapter 2 follows the content of this discourse across the break-down of post-war growth and its subsequent identification with "radical" Thatcherism. In Chapter 3, the contradictions accumulated in this shift from a thematics of caution to one emphasizing a radical break with consensus, are examined through the figure of the heretical manager, the pragmatist who presides over the inherently revolutionary fabric of capitalist space and innovation. Finally, the conclusion thinks through the ways in which the radical center functions within a broader cultural sensation of middleness very much a basic part of life in postmodern societies.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Vibration of an Inflatable, Self-Rigidizing Toroidal Satellite Component

contributor:
Dokainish, Mohammed Ali
Ziada, Samir
Mechanical Engineering

subject: vibration, inflatable, toroidal, satellite, component, self-rigidizing

abstract:
 Inflatable structures have attracted much interest in space applications. The three main components of inflatable satellites are inflatable struts, an inflatable torus as the structural support component, and some sort of lens, aperture, or array housed inside the boundary of the torus. This project is devoted towards understanding the dynamic characteristics of an inflated torus with a focus on the self-rigidizing torus, SRT, developed by United Applied Technologies.

 The self-rigidizing torus is manufactured from flat sheets of Kapton® that are formed into curved films with the regular pattern of hexagonal domes. The inflated torus can support its structural shape even when there is no internal pressure.

 Modal testing is used to determine the dynamic properties of the structure for comparison with the numerical model. The feasibility of using a non-contact in-house fabricated electromagnetic excitation is investigated. The first four, in-plane and out-of-plane, damped natural frequencies and their corresponding damping ratios and modes shapes are extracted and compared with prior experimental studies. A preliminary finite element modal analysis is carried out for a torus made of flat film and the results are compared with prior studies. Kapton 300JP®'s frequency-dependent modulus of elasticity is determined.

 Owing to the large number of hexagonal domes in the self-rigidizing torus, a simplified sub-structuring technique is used. Each hexagonal dome is replaced with a statically equivalent flat hexagon with the same mass and stiffness as the hexagonal dome. Then the finite element modal analysis of the self-rigidizing torus is carried out for an equivalent torus made of flat film. The geometric nonlinearity and the effect of the follower load on the stiffness are included in this analysis. The methodology is verified through the correlation between the analytical and modal test results of the self-rigidizing torus.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: A Self-Organizing Computational Neural Network Architecture with Applications to Sensorimotor Grounded Linguistic Grammar Acquisition

contributor:
Watter, Scott
Psychology

subject: self-organizing, computational, neural, network, architecture, applications, linguistic, grammar

abstract:
 Connectionist models of language acquisition typically have difficulty with systematicity, or the ability for the network to generalize its limited experience with language to novel utterances. In this way, connectionist systems learning grammar from a set of example sentences tend to store a set of specific instances, rather than a generalized abstract knowledge of the process of grammatical combination. Further, recent models that do show limited systematicity do so at the expense of simultaneously storing explicit lexical knowledge, and also make use of both developmentally-implausible training data and biologically-implausible learning rules. Consequently, this research program develops a novel unsupervised neural network architecture, and applies this architecture to the problem of systematicity in language models.

 In the first of several studies, a connectionist architecture capable of simultaneously storing explicit and separate representations of both conceptual and grammatical information is developed, where this architecture is a hybrid of both a self-organizing map and an intra-layer Hebbian associative network. Over the course of several studies, this architecture's capacity to acquire linguistic grammar is evaluated, where the architecture is progressively refined until it is capable of acquiring a benchmark grammar consisting of several difficult clausal sentence structures - though it must acquire this grammar at the level of grammatical category, rather than the lexical level.

 The final study bridges the gap between the lexical and grammatical category levels, and
develops an activation function based on a semantic feature co-occurrence metric. In concert
with developmentally-plausible sensorimotor grounded conceptual representations, it is shown
that a network using this metric is able to undertake a process of semantic bootstrapping, and
successfully acquire separate explicit representations at the level of the concept, part-of-speech category, and grammatical sequence. This network demonstrates broadly systematic behaviour on a difficult test of systematicity, and extends its knowledge of grammar to novel sensorimotor-grounded words.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Experimental Study and Modeling of Nucleate Boiling During Free Planar Liquid Jet Impingement

contributor:
Hamed, Mohamed S.
Shoukri, Mamdouh
Mechanical Engineering

subject: modeling, nucleate, boiling, planar, liquid, jet, impingement

abstract:
 Determination of boiling heat transfer rate during liquid jet impingement cooling (LJIC) depends on the intensity of bubble generation that is dependent on many flow and surface conditions such as jet velocity, liquid temperature, and surface superheat. Many empirical correlations have been developed previously to determine the total wall heat flux under various LJIC flow velocity, subcooling and surface superheat. However, only few studies have been able to model the governing heat transfer mechanisms associated with LJIC. In many industrial applications, there is a need to determine the effect of any changes in processing parameters on the total rate of heat transfer. Mechanistic heat transfer models can fulfill such need and allow for efficient model modifications at minimum cost and time.

 Three models have been developed in this study that address the underlying physics associated with jet impingement heat transfer in both single phase and nucleate boiling regimes. The first model accounts for the effect of bubble generation on the overall heat transfer rate at the jet stagnation by introducing a bubble-induced diffusivity (BID). The BID is added to molecular diffusivities in the momentum and energy Equations. The BID model adopts an analogous approach to the eddy diffusivity concept used in turbulence flow modeling. The BID model has been developed to provide a cost effective simulation tool of boiling heat transfer during LJIC by considering bubble generation effect on the overall heat transfer rate while avoiding the need to simulate extremely small time and length scales associated with phase change.

 The second model is a scenario identification procedure (SIP) that has been developed to predict the bubble growth termination (BGT) scenario. Considering the effect of jet velocity, water subcooling and surface superheat, the SIP identifies whether a bubble would locally collapse or slide by identifying the most probable equilibrium condition (thermal or dynamic) that the bubble would reach first. The main objective of the SIP is to avoid any inaccurate assumption of the probable BGT scenario. In this case, such procedure could improve the predictions of a more comprehensive wall heat flux model of the areas affected by various heat transfer mechanisms.

 The third model is a mechanistic wall flux partitioning (WFP) model that has been developed to predict the local wall heat transfer rate over the distance between jet stagnation and ten times the jet width. The WFP model assumes that primary heat transfer is due to sensible heating of liquid by forced convection and transient conduction. The WFP model incorporates a unified single-phase heat transfer model that is capable of capturing the observed secondary peaks downstream of stagnation. The WFP model also incorporates a sub-model that predicts abrupt changes in the liquid film thickness due to the formation of hydraulic jumps.

 The development of these three models have been carried out using experimental data obtained from a set of experiments that has been conducted to investigate the variation of the heat transfer rate and bubble dynamics under a planar free liquid jet. Investigation of bubble dynamics has been conducted using both intrusive optical probe and non-intrusive high speed imaging of the flow filed. The experiments have been conducted at atmospheric pressure, considering jet velocity of 0.4 to 1.7 m/s, degree of water subcooling of 10 to 28 °C, degree of wall superheat of -25 to 30 °C. Such variations have been studied along a heated surface between stagnation and ten times the jet width. Experiments were conducted using a 1 mm x 8 mm planar jet impinging on a heated horizontal flat copper surface. The distance between the jet and the heated surface was 10 mm. The experimental data have been used to develop a group of sub-models for single-phase heat transfer, bubble diameter, bubble population density, bubble release frequency, and bubble growth time. These sub-models have been used in the closure of the aforementioned models.

 The three models have been validated using independent experimental data. The BID model is capable of predicting stagnation heat flux within -15% and +30%. The SIP model was able to predict the right bubble growth termination scenario of 80% of the investigated cases. The WFP model is capable of predicting the local total wall heat flux within± 30%.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: INFLAMMATION, SLEEP DISTURBANCES AND THEIR RELATIONSHIP TO DEPRESSIVE SYMPTOMS DURING THE PERINATAL PERIOD

contributor:
Steiner, Meir
Frey, Benicio N
Neuroscience

abstract:
Introducton: The pathophysiology of perinatal depression is not completely under- stood. Advances in our understanding of Major Depressive Disorder (MDD) suggests that inflammation and sleep disruptions are important pathophysiological factors. The unique biological interactions between immune functioning, sleep disruptions and the Hypothalamic Pituitary Adrenal (HPA) axis may make these factors especially impor- tant for the development of depression during the perinatal period. The goal of this thesis was to thoroughly examine both inflammation and sleep disruptions from late pregnancy through the early postpartum period and assess how they might be related the development of depressive symptoms.
Results: Pregnancy IL-6 and IL-10 emerged as significant predictors of postpartum de- pressive symptoms. None of our other candidate inflammatory markers were associated with depressive symptoms during pregnancy, at 12 weeks postpartum or over time. Sig- nificant relationships were observed between mild depressive symptoms and disruptions in daily rhythms during pregnancy and at 3 months postpartum. We observed signif- icant trait level differences in objective measures of sleep in women at higher risk for PPD (i.e those with a history of recurrent MDEs). Significant differences in the rela- tionship between sleep and depressive symptoms across the perinatal period were also observed. For women with a history of recurrent MDEs, depressive symptoms during pregnancy appeared to be a trait rather than state phenomena. Our work is also the first to provided evidence linking objective (duration, efficiency and wake after sleep onset (WASO)) sleep parameters with small, but significant increases in IL-6 from late pregnancy to 12 weeks postpartum.  Conclusion: In sum, our results fail to show a state association between biomarkers of inflammation and perinatal depressive symptoms. Our work indicates that diagnostic history modulates the relationship between sleep and perinatal depressive symptoms. This diagnostic history also modules the trajectory of these sleep parameters from late pregnancy to early postpartum. Finally, our results provide foundational evidence for an interaction between inflammation and sleep disturbances across the perinatal period.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: DEVELOPING AND EVALUATING THE USE OF A WORKBOOK FOR CONTEXTUALIZING HEALTH SYSTEMS GUIDANCE

title: CONTEXTUALIZING GUIDANCE FOR HEALTH SYSTEMS STRENGTHENING

contributor: Clinical Epidemiology/Clinical Epidemiology & Biostatistics

subject:
health systems and policy
health systems strengthening
contextualization
qualitative research
case study
critical interpretive synthesis

abstract: Strong health systems are needed to implement clinical and public health interventions. Global evidence-informed health systems guidance, such as that created by the World Health Organization (WHO), has been used to help strengthen health systems. However, global guidance needs to be contextualized or adapted to fit the realities of a particular setting. A workbook for contextualizing health systems guidance was developed to accompany WHO guidance on optimizing health worker roles to increase access to and use of key interventions for improving maternal and newborn health. This dissertation investigates the development and use of the workbook, using qualitative research methods, to help in the planning of future knowledge translation tools, to provide insights for practice and research, and to improve the workbook. First, a single case study explores the development of the workbook, which helped uncover the key features of the process, barriers that arose, and facilitators that helped overcome some of these barriers (chapter 2). Second, a single embedded case study examined the use of the workbook in two real-life settings, Peru and Uganda (chapter 3). Third, a critical interpretive synthesis of the literature was used to better define contextualization and to find what and how contextual factors could be used by policymakers to adapt guidance to their setting (chapter 4). Together, the three studies presented in this dissertation offer substantive, methodological and disciplinary contributions to the field of health systems and policy through a comprehensive examination of the workbook. It presents recommendations for improving the workbook from the perspectives of global guidance developers, users at the national level, and the broader literature on guidance and guideline development, contextualization and implementation. It also supports the continued use of workbooks, or other tools, to contextualize guidance in an effort to strengthen health systems, especially in low- and middle-income countries.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)

abstract: Strong health systems are needed in order for the right mix of clinical care and public health interventions to get to those who need them. The World Health Organization writes guidance at the global level to help countries strengthen their health systems. This guidance can be used to develop health guidance or policy for the national or subnational (e.g., provincial, state) level, but it first needs to be contextualized or adapted to that particular jurisdiction. It is important to consider what the problem is and what causes it, policy options to help deal with the problem, implementation considerations, as well as factors related to both the health system and the political system that can affect whether or not the intervention will be implemented. A workbook was developed to help contextualize guidance. This dissertation explores the process of developing and evaluating its use to help in the planning of future tools, to provide insights for practice and research, and to improve the workbook.


title: An HVDC Off-shore Wind Generation Scheme with High Voltage Hybrid Generator

contributor:
Schofield, Nigel
Electrical and Computer Engineering

abstract: This thesis proposes a high voltage DC generation system for off-shore wind applications. The proposed scheme consists of a high voltage (HV) hybrid generator, a passive rectifier, DC/DC converters and HVDC interconnection and transmission. The HV hybrid generator prime mover is a wind turbine that may incorporate a gear-stage or be a direct drive system. Two regions of operation for the wind turbine are proposed; a limited speed region and a high speed operation region. The proposed system is studied and compared with a commercial off-shore wind system installed in the UK. The analyses are carried out considering system steady-state operation to identify system envelope specification requirements, key technology gaps, benefits and system performance and deduce component ratings. The proposed system results in higher efficiency, lower mass for the turbine power-train and also interconnections and transmission cables. The hybrid generator in this thesis is a high voltage machine with two rotor components namely a wound field (WF) and a permanent magnet rotor. Two designs for the HV hybrid generator are proposed; a surface PM rotor and an embedded PM rotor design. The DC wound field is the same for both designs while both design have a 9-phase stator winding. Finite element analysis (FEA) is used to study the machine electro-magnetic performance and MATLAB to process the results data. Machine losses including copper, windage and friction are calculated while the iron losses are predicted analytically from the machine field solution information and materials characteristics. Different insulation systems for the HV winding are studied based on commercial high voltage winding practice with the conclusion that the winding scheme is highly practicable.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: NUMERICAL STUDY OF DEFORMATION MECHANISMS IN HCP METALS

contributor:
Wu, Peidong
Mechanical Engineering

subject: Crystal Plasticity

abstract:
The operative deformation mechanisms which include both dislocation slip and twinning have a significant impact on the mechanical response of hexagonal close-packed (HCP) metals. Twinning plays an important role in accommodating plastic deformation due to the limited number of independent slip systems in HCP metals. The objective of this research is to study the deformation mechanisms associated with twinning in HCP metals (magnesium and zirconium alloys).
         Heat treatments are often involved in the manufacturing of zirconium alloys. These alloys exhibit a strong thermal anisotropy with a thermal expansion coefficient along the c-axis nearly two times of that along a-direction. Therefore, residual stresses/strains are generated during the heat treatment process which influences the mechanical response (e.g. lattice evolution) under subsequent loading. The elastic viscoplastic self-consistent (EVPSC) model has been improved which includes thermal strain to study the behavior of a Zircaloy-2 slab under moderately large strains. Various self-consistent schemes (SCSs) of the EVPSC model are evaluated in terms of the deformation behavior of the material under different uniaxial strain paths. Numerical results show that the Affine and Meff=0.1 self-consistent models give much better performance for the Zircaloy-2 slab than the Secant and Tangent models.
        The EVPSC-TDT model has been employed to mimic the twinning and detwinning behavior of extruded Mg alloy ZK60A under monotonic and cyclic loading. The model differentiates between the stress required to initiate twinning and that required to grow (thicken) existing twins. This enables the model to simulate the unusual sharp yielding behavior during twinning as well as the gradual yielding associated with detwinning. It is demonstrated that this model gives a good prediction of the strength anisotropy, strength asymmetry, and strain hardening behavior along different directions, for cases in which the contribution of twinning is large, small and intermediate. For the first time, the lattice strain evolution is well predicted in an extruded magnesium alloy under cyclic loading which involves twinning and detwinning.
         In all polycrystal models, an empirical equation for the termination of twinning in a grain is required. A new physics-based empirical equation for describing this phenomenon in magnesium alloys has been proposed in this study. It should be noted that the popular empirical equation currently used in all polycrystal models is applied at the grain level, while the new empirical equation is introduced at the twinning system level. The new description is represented by a single parameter while the commonly used empirical equation depends on two parameters. It is demonstrated that the proposed empirical equation is easily calibrated with the single parameter and is able to accurately simulate the experimentally observed rapid hardening associated with twinning exhaustion.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Dynamic Soil Water Repellency in Hydrologic Systems

type: Animation Thesis

contributor:
Smith, James E.
Earth and Environmental Sciences

subject: hydrology, soil science, environmental science, dynamic soil water repellency, infiltration, sorptivity, ethanol, MED, molarity of ethanol drop, water drop penetration time, water repellency cessation time, time to first bubble, time to first five bubbles, fractional wettability, contact angle, contact angle dynamics, mixed wettability, μXCT, X-ray microtomography, tension infiltrometer

abstract: Dynamic soil water repellency is an important soil phenomenon in the vadose zone as it is now recognised that most soils in the world are likely to express some degree of reduced wettability and/or long term hydrophobicity. Fractional wettability and contact angles are, however, rarely discussed or quantified for natural systems. This is particularly the case in the presence of dynamic contact angles. Soil water repellency remains a persistent impediment and challenge to accurate conceptual and numerical models of flow and storage in the vadose zone. This dissertation addresses the opportunity and pressing need for contributions that develop better quantifiable definitions, descriptions, and understanding of soil water repellency. Using materials collected from post wildfire sites, this work employs water and ethanol to identify, isolate, and quantify contact angle dynamics and fractional wettability effects during infiltration. Varied concentrations of water and ethanol solutions were applied to soils and observed through X-ray microtomography, tension infiltration experiments, and moisture content measurements in the laboratory and field. Several analyses from lab and field investigations showed that applications of ethanol and specifically, water-ethanol aqueous solutions provide unique additional insights into proportions of media that remain non-wettable and how those proportions affect overall hydrologic processes, which are not readily observable through water infiltrations alone. Observations include the wetting up of microporous structures, reduced storage, and changes in unsaturated hydraulic conductivities. Challenges which develop as a consequence of variable fluid properties including changes to operational pore assemblages, slow down of wetting fronts, and non-uniqueness relative to infiltration responses are addressed. Important insights and contributions were developed through this approach and water-ethanol mixtures are valuable tools for developing greater quantification and mechanistic data to better inform our models and understanding of dynamic soil water repellency.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)

abstract: Quantifying fluid behaviours in soils is important for a host of environmental, social, and economic reasons. Over the last 25+ years, one soil phenomenon has garnered increased attention because it interferes with our ability to carry out this work. Soils that are or become water repellent develop all over the world and where hydrophobic or non-wetting substances can enter soil and remain in pore spaces or as coatings on particles. To assist in the tracking and management of its complex effects on water storage and infiltration, the goals of this work were to develop fundamental insights into the manifestation and effects of this variable soil property on key hydrologic properties and processes. This work tests a new conceptual model for understanding these systems through both field and laboratory work and using a number of different technologies. These include X-ray microtomography (μXCT), tension infiltrometry, and more regularly applied techniques which are sensitive to changes in repellency. The works shows how combining fractional wettability and contact angle dynamics generates a stereoscopic conceptual framework which facilitates increased capacity for quantifying and understanding of soil systems expressing dynamic soil water repellency.


title: THE EVALUATION OF THE VASCULAR DISEASE SELF-MANAGEMENT INSTRUMENT FOR ADULTS RECEIVING IN-CENTER/SATELLITE AND HOME HEMODIALYSIS: A FEASIBILITY STUDY

contributor:
Browne, Gina
Nursing

subject: self-management, feasibility study, hemodialysis, home hemodialysis

abstract:
Background. A reliable and valid instrument printed in English that measures self-management for adults with vascular diseases receiving hemodialysis therapy was not found in the literature. The Vascular Disease Self-Management Instrument (VSMI) was developed to support the measurement and assessment of self-management.
Objectives. The primary objective was to assess the feasibility of the study methods to develop and explore the psychometric properties of the Vascular Disease Self-Management Instrument (VSMI) for adults receiving hemodialysis therapy. Feasibility outcomes included recruitment, consent and completion rates. The secondary objective was to begin to explore the reliability (internal consistency and test-retest), and construct validity using exploratory factor analysis and criterion-related validity.
Method. This feasibility study used seminal work (Thabane et al., 2010) and clinical expertise to determine feasibility outcomes. Examination of psychometric properties was based on Streiner & Norman (2008).
Results. Of the 267 eligible patients, a total of 136 patients were recruited into the study. The consent rate was 51% and completion rate was 32% for the test-retest analysis. Study participants were primarily male (61%), diagnosed with chronic kidney disease for 12 years and receiving hemodialysis therapy for 6 years. Half (50%) the participants were at moderate risk for psychological distress and used avoidant-oriented coping. Preliminary psychometric analysis suggested good reliability (Cronbach’s alpha = 0.945) and stability (Intraclass correlation coefficient = 0.927, p <0.0001). The results of the exploratory factor analysis indicated four main factors comprised the self-management instrument including collaborative partnerships, self-advocacy, self-monitoring and normalcy. Preliminary evidence of criterion-related validity demonstrated a significant positive relationship between task-orientated coping and self-management.
Conclusion. Feasibility outcomes were successfully met. Preliminary evidence suggests that the VSMI has the potential to become a reliable and valid instrument. A full-scale psychometric evaluation with a sample that includes adults receiving peritoneal dialysis is needed to support utilization of the VSMI in research and clinical practice.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)

abstract:
Background: Adults receiving dialysis therapy must engage in self-management of their illnesses. A questionnaire on self-management activities based on the individuals’ experiences would help health care providers to identify areas where people struggle. This information could be used to develop programs that support self-management.
What Did We Learn: A total of 136 people took part in the study. The development and testing of a self-management questionnaire for adults undergoing hemodialysis is a worthwhile and reasonable goal. The questionnaire provided people with the opportunity to describe their self-management activities. Half the people that participated in the study were at risk for experiencing anxiety and depression and tried to avoid stress.
Conclusions: The questionnaire would assist health care providers to engage in future research projects and develop programs and resources that help people more independently manages their illnesses.


title: CALIBRATION OF THE JOHNSON-COOK FAILURE PARAMETERS AS THE CHIP SEPARATION CRITERION IN THE MODELLING OF THE ORTHOGONAL METAL CUTTING PROCESS

contributor:
Ng, Eu-Gene
Mechanical Engineering

subject:
Calibration methods
Johnson-Cook fracture parameters

abstract: The finite element analysis (FEA) is a numerical method widely used to predict the metal-cutting performance in both academic and industrial studies, avoiding the high expense and time consumption of experimental methods. The problem is how to calibrate reliable fracture-parameters as chip-separation criterion are implemented into FEA modelling. This thesis introduces a calibration method of the Johnson-Cook fracture parameters used in the orthogonal metal cutting modelling with a positive rake angle for AISI 1045 steel. These fracture parameters were obtained based on a set of quasi-static tensile tests, with smooth and pre-notched round bars at room temperature and elevated temperatures. The fracture parameters were validated by low- and high-strain rate simulations corresponding to tensile tests and orthogonal metal-cutting processes respectively in ABAQUS/Explicit. Compared to literature calibration methods, this method is simpler, less expensive but valid.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Timed Fault Tolerant Supervisory Control

contributor:
Leduc, Ryan
Computing and Software

subject: TDES, DES, fault tolerant

abstract:
With the ever growing complexity of computer-controlled systems, the need for discrete-
event systems has emerged. Many contributions have been done to improve and dis-
cuss discrete-event system properties. In this thesis, we investigate the problem of
fault tolerance in timed discrete-event systems.
Our goal is to establish a timed fault tolerant supervisory control approach. We start
by presenting our settings and providing different fault scenarios. We then provide
four fault tolerant definitions to verify that the system will remain controllable in
each scenario. Also, we introduce algorithms to verify timed controllability for each
scenario.
We implement a tool extension for the software research tool, DESpot, to verify timed
controllability. Furthermore, we implement a tool extension to verify fault tolerant
untimed controllability and nonblocking, and timed fault tolerant controllability for
the fault scenarios.
Finally, we present a simple example to illustrate our approach.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Large-Scale Dynamic Optimization Under Uncertainty using Parallel Computing

contributor:
Swartz, Christopher L.E.
Chemical Engineering

subject: Dynamic Optimization; DAE process models; Parallel Computing

abstract:
This research focuses on the development of a solution strategy for the optimization of
large-scale dynamic systems under uncertainty. Uncertainty resides naturally within the
external forces posed to the system or from within the system itself. For example, in chemical
process systems, external inputs include flow rates, temperatures or compositions; while
internal sources include kinetic or mass transport parameters; and empirical parameters
used within thermodynamic correlations and expressions. The goal in devising a dynamic
optimization approach which explicitly accounts for uncertainty is to do so in a manner
which is computationally tractable and is general enough to handle various types and
sources of uncertainty. The approach developed in this thesis follows a so-called multiperiod
technique whereby the infinite dimensional uncertainty space is discretized at numerous
points (known as periods or scenarios) which creates different possible realizations of the
uncertain parameters. The resulting optimization formulation encompasses an approximated
expected value of a chosen objective functional subject to a dynamic model for all the
generated realizations of the uncertain parameters. The dynamic model can be solved,
using an appropriate numerical method, in an embedded manner for which the solution
is used to construct the optimization formulation constraints; or alternatively the model
could be completely discretized over the temporal domain and posed directly as part of the
optimization formulation.
Our approach in this thesis has mainly focused on the embedded model technique for
dynamic optimization which can either follow a single- or multiple-shooting solution method.
The first contribution of the thesis investigates a combined multiperiod multiple-shooting
dynamic optimization approach for the design of dynamic systems using ordinary differential
equation (ODE) or differential-algebraic equation (DAE) process models. A major aspect
of this approach is the analysis of the parallel solution of the embedded model within the
optimization formulation. As part of this analysis, we further consider the application of
the dynamic optimization approach to several design and operation applications. Another
vmajor contribution of the thesis is the development of a nonlinear programming (NLP) solver
based on an approach that combines sequential quadratic programming (SQP) with an
interior-point method (IPM) for the quadratic programming subproblem. A unique aspect of
the approach is that the inherent structure (and parallelism) of the multiperiod formulation
is exploited at the linear algebra level within the SQP-IPM nonlinear programming algorithm
using an explicit Schur-complement decomposition. Our NLP solution approach is further
assessed using several static and dynamic optimization benchmark examples.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Challenging Current Exercise Prescription for Osteoarthritis of the Knee with a Yoga-Inspired Approach

title: Efficacy of a Biomechanically-Based Yoga Exercise Program for Knee Osteoarthritis: a Randomized Control Trial

contributor:
Maly, Monica
Kinesiology

subject:
osteoarthritis
knee
exercise
yoga
pain
physical function

abstract: A randomized, controlled, clinical trial of a yoga-based exercise intervention for knee osteoarthritis

abstract:
Background:  Knee osteoarthritis is a chronic disease involving the breakdown of joint tissues resulting in pain and disability.  Exercise provides equivalent pain relief to medication, improves physical functioning, and ameliorates co-morbidities.  However, certain forms of exercise can potentially overload the joint and exacerbate symptoms; the optimal type is unknown.  We developed a yoga-based exercise intervention designed for knee osteoarthritis by incorporating postures that minimize a mechanical loading variable implicated in disease progression.
Purpose:  The objective was to compare the efficacy of this biomechanically-tailored yoga program as treatment for knee osteoarthritis with the current “gold standard” of physical therapy, and a no-exercise attention control group.
Methods:  A single-blinded, 12-week, 3-arm, parallel randomized control trial was conducted.  Participants (women 50 years or over, with clinical knee osteoarthritis; n=31) were stratified by disease severity and randomized to receive biomechanical yoga exercise (YE; n=10), traditional exercise (TE; n=11), or no-exercise (NE; n=10).  The primary outcome measure was pain; secondary outcomes included patient-reported physical function and mobility performance; and tertiary outcomes included muscular strength, quality-of-life, and symptoms of depression.
Results:  The YE and TE groups demonstrated statistically and clinically significant within-group improvements in pain, physical function, and mobility performance (p<0.017), while the NE group did not.  The YE group reported greater improvements in pain compared to the NE group (p=0.003).  The YE group also demonstrated greater improvements in physical function compared to NE (p=0.010).  There were no significant between-group differences in mobility performance, strength, quality-of-life, or depression (p>0.05).
Conclusion:  Yoga appears as an efficacious and well-tolerated conservative treatment option for women with knee osteoarthritis.  The yoga intervention yielded comparable, and in some cases possibly greater improvements in the major burdening symptoms of the disease compared to traditional physical therapy.  Future investigations with larger samples are warranted to establish effectiveness and possibly superiority to traditional exercise.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: Osteoarthritis of the knee is a debilitating joint disease and a leading cause of disability.  Treatment often involves medication to control pain and surgery when drugs fail.  Exercise is a conservative approach to improve symptoms and quality of life.  Some forms of exercise however can overload the knee and possibly worsen the disease.  We have developed a yoga-inspired exercise regimen specifically for knee osteoarthritis that minimizes damaging mechanical loads.  To test this program, women with knee osteoarthritis were randomly assigned to receive either 12 weeks of yoga, traditional physical therapy, or no-exercise.  Before and after the intervention, pain, physical function, and mobility were measured.  The yoga and traditional exercise groups demonstrated improvements in pain, physical function, and mobility; while the no-exercise group did not.  In some aspects, yoga even outperformed traditional exercise.  These findings suggest yoga is as effective as traditional exercise, and potentially more so, in treating knee osteoarthritis.


title: Constrained-Random Stimuli Generation for Post-Silicon Validation

contributor:
Nicolici, Nicola
Electrical and Computer Engineering

abstract:
Due to the growing complexity of integrated circuits, significant efforts are undertaken to ensure the design and implementation meet the specification and quality requirements both at the pre-silicon verification stage (before tape-out), as well as at the post-silicon validation stage (on the silicon prototypes). In particular, the constrained-random methods, which subject the design to a large volume of random, yet functionally-compliant stimuli, are widely employed during the pre-silicon stage. Hardware description languages, such as SystemVerilog, have standardized and well-defined features to formalize the constraints including format, sequence control and distribution. Nonetheless, it is not obvious how such features can be efficiently leveraged at the post-silicon stage.

In this dissertation, a systematic methodology is proposed to support constrained-random generation and application during post-silicon validation. This includes both software algorithms and on-chip hardware structures. The proposed software translates functional constraints from SystemVerilog into a cube-based representation. A method to design in-field programmable signal generators, which are placed on-chip, can directly expand compacted cubes to extensive random, yet functionally compliant, sequences for post-silicon validation. This approach is extended to also support sequential constraints, as well as the control of the stimuli distribution.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)


title: A landscape approach to evaluate sources of nutrient and sediment to the Nottawasaga River, a tributary of Georgian Bay, Lake Huron

contributor:
Chow-Fraser, Patricia
Biology

subject:
phosphorus
suspended solids
tributary loading
watershed
in-stream processes

abstract: The overall goal of this thesis is to present a comprehensive understanding of the Nottawasaga River system. In the first chapter, we will examine how landscape features (geomorphology and land cover) drive spatial variation in nutrient and sediment loading from 11 sub-watersheds to the Nottawasaga River. The second chapter will relate how tributary loading and other in-stream processes (riffles, substrate, dissolved oxygen) contribute to the longitudinal variation in water quality along with middle and lower reaches of the Nottawasaga River. Finally, in the last chapter we use 13 water quality variables to develop a Stream Water Quality Index (SWQI) to identify critical areas in the NRW that are most at risk. This thesis will provide environmental agencies with useful information to help implement management strategies to improve the health of riverine systems at a watershed scale.

abstract: Eutrophication from agricultural runoff is a global problem, often resulting in formation of anoxic zones in receiving water bodies. The Nottawasaga River Watershed (2,900 km2) is dominated by agricultural land-use, and is a major source of nutrients and sediment to Nottawasaga Bay, Georgian Bay (Lake Huron). The primary objective of our study was to develop a holistic understanding of the different sources and processes that influence spatial variation of water quality across the Nottawasaga River (121 km). In our first chapter, we use landscape features to develop 6 models that predict daily base flow loading rates of total phosphorus (TP) and total suspended solids (TSS) from 11 sub-watersheds. We found that drainage area and % pasture land were the most significant predictive variables driving spatial variability in TP and TSS loading. We also found a significant positive relationship between TP and % wetland, suggesting that the Minesing Wetlands (largest inland wetland in southern Ontario) are a source of nutrients to the river. In our second chapter, we evaluate how tributary inputs and in-stream processes contribute to the longitudinal variation in water quality along the Nottawasaga River. We found that tributary concentration and discharge significantly predict downstream turbidity (TURB), but do not predict downstream TP. We also found that riffles improve water clarity, and that silt and clay substrate is significantly associated with high TURB. In our third chapter, we develop a Stream Water Quality Index (SWQI) using 13 variables collected at 15 stations along the Nottawasaga River. To predict SWQI scores for any site, we have provided 9 equations that use various combinations of available variables. Understanding landscape variables, as well as tributary and in-stream processes that influence water quality will enhance the development of restoration initiatives to improve ecosystem health in lotic systems at a watershed scale.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: Eutrophication from agricultural runoff is a global problem, often resulting in formation of anoxic zones. The Nottawasaga River Watershed is dominated by agricultural land-use, and is a major source of nutrients and sediment to Georgian Bay, Lake Huron. The objective of our study was to develop a holistic understanding of sources and processes that influence spatial variation of water quality across the Nottawasaga River. We found that landscape features (drainage area, pasture, wetland), tributary inputs, and in-stream processes (riffles, substrate) significantly influence water quality. Our results will enhance restoration initiatives to improve health of riverine systems at a watershed scale.


title: In Vivo Measurement of Aluminum in Alzheimer's Disease and Related Studies

contributor:
Chettle, David
Medical Physics

subject:
In vivo neutron activation analysis
Aluminum
Alzheimer's Disease
Bone
Magnesium
Data analysis
Gamma spectrometry
Biological half-life

abstract: Alzheimer’s disease accounts for up to 80% of the cases of dementia making it the most common type of dementia.  As of 2015, 46.8 million people are suffering from Alzheimer’s disease worldwide with an alarming rate of increase in the onset of the disease. Despite the ongoing research, the true cause of Alzheimer’s disease remains unknown. Aluminum is one of the major environmental toxins linked to the etiology of Alzheimer’s disease. A pilot clinical study for non-invasive measurement of bone aluminum was performed at the in vivo neutron activation analysis facility at McMaster University including 15 Alzheimer’s and 15 control subjects. A significant difference in bone aluminum, relative to calcium, was found between the two groups. Multiple methods of analysis were investigated to determine the method with the lowest minimum detection limit. The method of in vivo neutron activation analysis allows for the simultaneous activation of multiple elements. As such, it was possible to measure the magnesium levels, which has been shown to be involved in Alzheimer’s disease, in the study subjects. The results of bone measurements did not show a significant association between bone magnesium levels and Alzheimer’s disease. Moreover, the short-term kinetic behaviours of sodium and chlorine, both essential for the human body, were studied. The outcome of this study revealed an increase in the biological half-lives of sodium and chlorine with age and a higher variability in Alzheimer’s patients compared to control subjects. Finally, bone samples from parenteral nutrition patients were analyzed to determine their aluminum content for comparison and benchmarking purposes. The present results suggest a possible association between bone aluminum and the presence of Alzheimer’s disease. No such association was found for magnesium or the biological half-lives of sodium and chlorine. The technique of in vivo neutron activation analysis was shown to be a promising tool for measuring bone aluminum and magnesium; however, a better detection limit is required to strengthen the current results.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)

abstract: Alzheimer’s disease is the most common form of dementia. The cause of Alzheimer’s disease is unknown, but both genetic and environmental factors are known to be involved. Different elements have been studied for their possible role in this disease. Aluminum and to a lesser extent magnesium have been linked to the etiology of Alzheimer’s disease. The current thesis presents the results of a clinical study that utilizes the method of in vivo neutron activation analysis to measure aluminum and magnesium in the hand bone of Alzheimer’s disease and control subjects. In vivo neutron activation analysis is a non-invasive method that uses neutrons to activate elements in the human body and measures the radiation emitted. Different methods of analyzing the resulting data were investigated to find the most suitable analysis approach. The biological half-lives of sodium and chlorine were also measured to investigate their short-term kinetic behaviour and pattern with age.


title: Facies Analysis and Paleodischarge of Rivers within a Compound Incised Valley, Cretaceous Ferron Sandstone, Utah

contributor:
Bhattacharya, Janok
School of Geography and Geology

subject:
Geology
Sedimentology
Facies Analysis
Sequence Stratigraphy

abstract: Classification of river systems based on dimension and lithology of architectural elements is critical in determining their scale and role in ancient drainages as tributaries, distributaries, or trunk river systems. Facies boundaries associated with the zonation of the fluvio-estuarine system can be difficult to predict using standard facies and sequence stratigraphic models, particularly within broad, long-lived compound incised valley fills. These questions are addressed in an outcrop study of incised valleys in the Turonian Ferron Sandstone Member of the Western Interior Seaway, southern Utah. Field data includes 8 measured sections containing detailed lithological, ichnological, paleocurrent, and architectural data, and 3 high resolution gigapan photomosaics of opposing outcrop faces oriented oblique to depositional dip. The compound valley records multiple episodes of cut and fill, with three nested valleys, each containing multiple channel stories. An upward progression from single thread meandering fluvial style, indicated by large scale laterally accreting point bar deposits, to more freely avulsing rivers in upper stories is documented. Lithological analysis of the oldest valley shows grain size distributions ranging from medium lower sandstone at the valley base to fine lower sandstone towards the top, and is characterized by amalgamated macroform deposits with dune scale crossbedding and abundant mud rip up clasts throughout. The second shows variable estuarine laterally accreting point bars, which coarsen away from the valley margin. The youngest valley is dominated by fining upward successions passing from medium lower dune scale cross bedded sandstone at the base with few mud clasts, to rippled very fine upper sandstone and interfingered floodplain shale deposits. Tidal influence is documented; suggesting that rivers were positioned basinward of the paleo backwater length, and estuarine facies seen in V2 suggests they are within the bayline. These rivers are among the largest documented in the Ferron and show that fluvial style and scale changes regionally within this large valley system.

abstract: Thesis

abstract: Master of Science (MSc)


title: FABRICATION OF COMPOSITE ELECTRODES AND SUPERCAPACITOR DEVICES

contributor:
Zhitomirsky, Igor
Materials Science and Engineering

subject:
manganese dioxide
carbon nanotubes
supercapacitor
colloids
dispersion
bismuth manganese oxide
hybrid
voltage window
activated carbon
EPD

abstract:
Electrochemical supercapacitors (ECs) attract significant attentions for their unique characteristics of high power density, good cycling capability and low cost. This dissertation will focus on fabrication of composite materials for electrodes and devices of ECs. A conceptually new colloidal approach to the fabrication of metal oxide – multiwalled carbon nanotube (MWCNT) composites is proposed. The heterocoagulation of positively charged oxide nanoparticles and negatively charged MWCNT allows the
fabrication of advanced nanocomposites with improved dispersion of individual components. The proof-of-principle was demonstrated by the fabrication of MnO2-MWCNT electrodes for ECs with excellent performance.
We proposed another novel concept based on electrostatic heterocoagulation of MnO2-MWCNT composites in aqueous environment. In this case, Benzyldimethylhexadecylammonium chloride (BAC) surfactant and caffeic acid (CA) were selected for adsorption and dispersion of MWCNT and MnO2, respectively, and this allowed the formation of stable aqueous suspensions of positively charged MWCNT and negatively charged MnO2. The asymmetric device showed high capacitance, high powerenergy
characteristics with enlarged voltage window of 1.8 V, good capacitance retention at high charge-discharge rates and cyclic stability.                    A novel capacitive material BiMn2O5 was firstly discovered and synthesized for ECs applications in our studies. The BiMn2O5 nanocrystals were prepared by a hydrothermal method. We demonstrated for the first time that BiMn2O5 – MWCNT composite can be used as a new active material for positive electrodes of ECs. The composite electrode
with high mass loading showed a capacitance of 6.0 F cm-2 (540 F cm-3) at a scan rate of 2 mV s-1 and excellent capacitive behavior at high scan rates. As-fabricated device showed good cyclic stability in a voltage window of 1.8 V with energy density of 13.0 Wh L-1 (9.0 Wh kg-1) and power density of 3.6 kW L-1 (2.5 kW kg-1).
We firstly discovered that Poly[1-[4-(3-carboxy-4 hydroxyphenylazo)benzenesulfonamido]-
1,2-ethanediyl, sodium salt] (PAZO) can be used as an universal dispersant for various materials and its thin film fabricated by electrophoretic deposition (EPD) exhibited photo-induced birefringence. Our new findings indicated that PAZO is good candidate for diverse materials dispersing because it contains diaromatic monomers with
salicylate ligands, which can provide multiple adsorption sites for efficient adsorption on particles and impart electrical charges to the particles. Additionally, the use of PAZO polymer offers the advantages of improved steric stabilization.
We discovered that Celestine blue (CB) can be developed as an efficient dispersing agent for the nanoparticles. We found that CB includes a catechol ligand, which can provide CB adsorption on inorganic nanoparticles. The relatively large size of the CB molecules is
beneficial for the electrosteric dispersion. The benefits of cathodic EPD for
nanotechnology were demonstrated by the formation of nanostructured MnO2 films on commercial high surface area current collectors for energy storage in ECs.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Polymerized Silicone Microemulsions

title: The Polymerization and Application of Silicone Microemulsions in the Development of Nanostructured Materials

contributor:
Brook, Michael A.
Chemistry and Chemical Biology

subject:
Microemulsions
Polymerization
Silicone
Nanostructured Materials
Nano-titania

abstract:
Microemulsions are nanostructured dispersions that have unique properties, which make them attractive for applications such as biomaterials, drug delivery, and nanoparticle synthesis. The behaviour of hydrocarbon microemulsions and their applications have been extensively studied, however, there have been very few studies in the preparation or the polymerization of silicone microemulsions. Silicone microemulsions offer a unique template by which to create novel nanoporous silicone elastomers and/or hydrogels. The prevalent use of silicones in biomaterials, coatings, and personal care (to name a few) make the development of silicone-based microemulsions of particular interest.
The aim of thesis research was to polymerize silicone microemulsions and to understand the factors that contribute to retaining initial template morphology in the polymeric product. Chapter Two of this thesis focuses on the preparation of silicone microemulsions containing a non-polymerizable and polymerizable trisiloxane surfactant, respectively. Formulations were prepared and characterized by electrical conductivity to determine the microemulsion structure type. Formulations located in the bicontinuous region of the phase diagram were polymerized, producing transparent silicone elastomers.
The focus of Chapter Three was to determine the tolerance of silicone microemulsions to selected chemistry that is relevant to silicone polymers. Previous work done in the field of polymerizing silicone microemulsions has been based on radical polymerization processes. There are no reports that examine the polymerization of a silicone microemulsion by room temperature vulcanization (RTV), a common process for creating silicone elastomers. We aimed to better understand the effects of RTV cure on morphology retention from the liquid to polymeric product to determine if this type of chemistry could be used in the formation of nanoporous silicone elastomers either on its own or in conjunction with a radical polymerization process. In order to understand the effects of an RTV process on polymer structure, we examined the effect of the variable components (necessary for the RTV cure) on the silicone microemulsion template. Small angle X-ray scattering (SAXS) and transmission electron microscopy (TEM) were used as tools to characterize materials prior to and after cure. Silicone microemulsions that were cured using the RTV process produced nanoporous polymeric elastomers, however, the initial bicontinuous microemulsion template was not retained. RTV cured microemulsions retained the bicontinuous structure if the RTV cure was preceded by a photopolymerization reaction to “lock-in” surfactant monomers at the oil/water interface.
Chapter Four explores the use of silicone microemulsions as a reaction vehicle in the formation of nano-TiO2 particles. The focus of this chapter was the exploitation of microemulsion droplets and bicontinuous structures that were designed to retard TiO2 particle formation in situ. Titanium isopropoxide (TTIP) was incorporated into silicone microemulsions containing varying amounts of water. Interactions between TTIP and the trisiloxane polyether surfactant result in the formation of a compound containing a Ti4+, coordinated to silicone surfactant molecules via a polyether linkage. Titania forms in situ as water is titrated into the surfactant/oil mixture, resulting in the formation of a microemulsion. The formation of TiO2 was monitored by UV-Vis spectroscopy and the TiO2 particles were characterized using transmission electron microscopy.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: This thesis is about the chemical modification and polymerization of nanostructured liquids in the form of silicone microemulsions to create nanoporous silicone elastomers (nano is one billionth, 10-9, so 1 nanometer = 1 billionth of meter). Despite the highly prevalent commercial use of silicones and the utility of silicone elastomers, little is known about the polymerization of silicone microemulsions to create nanoporous materials. The first goal of this thesis was to polymerize silicone microemulsions, using methods that have been previously used in the polymerization of hydrocarbon microemulsions.  Silicone microemulsions were successfully polymerized using a reactive surfactant and rigidification of the oil phase was achieved using common silicone crosslinking chemistry. The second goal was to understand how the type of chemistry affects changes in structure upon transition from liquid microemulsion to solid polymer. Nanostructuring was retained in polymerized microemulsions both with and without oil phase polymerization. Finally, the third goal was to exploit silicone microemulsion domains to control titanium dioxide particle formation. Particle formation was slowed as a result of domain constricted particle growth.


title: DECORATIVE AND PROTECTIVE TiN COATINGS ON 304 STAINLESS STEEL USING CATHODIC ARC PVD

contributor:
Mascher, Peter
Engineering Physics

abstract: Titanium Nitride (TiN) coatings on the market today are known as very hard ceramic coatings most commonly deposited on metallic alloys such as stainless steel. Previous and current research into functional coatings demonstrated tremendous potential for various industrial applications. Primary focus in this research into TiN coatings is decorative coatings with scratch resistant properties specific to the cathodic arc PVD system used in this research. Individual parameters were varied while others kept constant prior to and during deposition. This created a unique set of samples in order to determine the most effective deposition recipe specific to the PVD system. Adhesion is a major factor to consider when developing coatings onto stainless steel. Two different cleaning methods are used to prepare the samples, one method being performed within a class 10,000 clean room. Initial research determined whether strong adhesion is dependent on external baking of stainless steel substrates by investigating various bake time and temperatures prior to deposition. Further research varied ion bombardment duration and voltage, TiN deposition duration, and nitrogen pressure and investigated their influence on scratch resistance and adhesion of the coatings. Scratch testing verified hardness and provided insight to the coating’s resistance to delamination with linearly increasing force. From these results, it became possible to identify the quality of adhesion between the TiN coating and stainless steel substrate.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Biological and Social Determinants of Suicidal Behaviour

contributor:
Samaan, Zainab
Neuroscience

subject:
Suicide
BDNF
Systematic review
Social factors
Sex differences

abstract:
Background: Suicide is a worldwide concern, claiming nearly one million lives each year. The causes of suicidal behaviour are unclear, but a variety of biological, psychological, social, and environmental factors are thought to contribute to suicide risk. Many cases of suicidal behaviour cannot be explained by conventional risk proposed by clinical and research observations. Recent research has focused on biomarkers of suicidal behaviour, including brain-derived neurotrophic factor (BDNF). This thesis aims to determine the association between BDNF and suicidal behaviour by reviewing the literature and by analyzing clinical data. An additional aim of this thesis is to explore the associations between social factors and suicidal behaviour, with a particular focus on sex differences within these factors.
Methods: We explored the associations between biological and social risk factors and suicidal behaviour in several ways. We conducted a systematic review to summarize and evaluate the literature regarding BDNF levels and suicidal behaviour. The protocol for this systematic review was designed and published a priori. We performed a qualitative review of the literature and a meta-analysis of studies of serum BDNF and attempted suicide. Then, we assessed the association between serum BDNF and attempted suicide using a case-control study design. We analyzed data collected from the Study of Determinants of Suicide Conventional and Emergent Risk (DISCOVER), and age- and sex-matched study of attempted suicide. In a sample of 250 participants (84 cases of attempted suicide, 104 psychiatric controls, and 93 community controls), we used linear regression analysis to determine the association between BDNF level and attempted suicide, adjusting for age, sex, body mass index, current smoking status, and antidepressant use. Finally, using the same dataset, we explored the associations of a number of social factors with attempted suicide. In a sample of 343 participants (146 cases, 104 psychiatric controls, and 93 community controls), we used logistic regression analyses to determine the associations between social risk factors and attempted suicide in men and women separately. These included age, education level, employment status, marital status, religious practice, stressful life events, and childhood abuse.
Results: Our systematic review included 14 studies. The meta-analysis of three studies of serum BDNF and attempted suicide showed no significant association. The qualitative review of all studies revealed inconsistent findings regarding associations between BDNF and suicidal behaviour. In our study of serum BDNF and attempted suicide in the DISCOVER dataset, attempted suicide was not significantly associated with BDNF level. In our study of social factors for attempted suicide, some sex differences were found: Completion of post-secondary education and religious practice were found to be significant protective factors against attempted suicide only in women, and unemployment and stressful life events were significant risk factors only in men.
Conclusion: This thesis provides important findings about the biological and social risk factors for suicidal behaviour. Understanding the determinants of suicidal behaviour can aid clinicians in identifying and treating vulnerable individuals.

abstract: Thesis

abstract: Master of Science (MSc)