VictorJuiz/thesis huggingface dataset:
Air Sparging and Pre-coagulation on Ultrafiltration Fouling and Pharmaceutical Retention

This research examined pre-coagulation and air sparging (surface shear stress) as fouling control strategies for ultrafiltration (UF) membranes during drinking water treatment of natural water matrices. In addition to fouling control, these treatment strategies were also examined with respect to any added benefit for the retention of organic micropollutants. A low coagulant dose (0.5 mg/L) was identified as optimum for biopolymer (foulant) removal, based on a point of diminishing returns analysis in three natural water matrices. This dose resulted in lower or equivalent fouling relative to a dose of 15 mg/L while providing similar retention of organic micropollutants (up to 40%). At pilot-scale, a 0.5 mg/L coagulant dose resulted in lower fouling (up to 77%) when compared to a 6 mg/L dose, while providing a similar reduction (up to 14%) of DBP formation. Shear stress at the membrane surface, associated with varying air sparging conditions, was found to significantly reduce UF fouling for all waters investigated. Fouling reduction was most pronounced in waters with higher concentrations of organics and biopolymers, as shear stress was determined to decrease the fouling rate via back-transport of biopolymers from the membrane surface, preventing or slowing their deposition. The greatest fouling reduction was achieved with shear stress representative of large, pulse bubble (>100 mL) air sparging. With respect to fouling control, the potential for significant cost savings (up to $1 million/year for a 100 MGD treatment plant) was observed with the application of either pulse bubble sparging or low coagulant dose (0.5 mg/L), based on fouling reduction and longer membrane run times between backwashes, leading to increased water production. In addition to fouling control, pulse bubble sparging may also significantly increase the retention of organic micropollutants by UF membranes, by reducing cake-enhanced concentration polarization at the membrane surface.

Keywords: Air sparging
Coagulation
Drinking water treatment
Fouling
Organic micropollutants
Ultrafiltration
Advisor: Andrews, C Robert
Regulation of Septin Complex Assembly and Roles in Cytokinesis and Ciliogenesis

Septins comprise a family of filament-forming GTPases that appear to be a novel component of the cytoskeleton. Septins form rod-shaped complexes that join end-on-end to polymerise into filaments, and assemble into higher-order structures such as bundled filaments and rings. These septin structures are thought to have two functions: one is to act as macromolecular scaffolds that recruit proteins to specific cellular locations and second, to serve as membrane diffusion barriers by confining distinct membrane domains. Both septin functions are required at the cleavage site of dividing cells, where septins recruit and confine membrane proteins that drive cytokinesis. Septin higher-order structures are found in diverse cellular contexts including neurons, migrating cells, cells with primary cilia, spermatozoa and host-pathogen interactions. The best insight into assembly of septin higher-order structures come from budding yeast. The four budding yeast septins are apolar octamers arranged as Cdc11-Cdc12-Cdc3-Cdc10-Cdc10-Cdc3-Cdc12-Cdc11, and two septin-septin interaction interfaces (NC and G) alternate within the octamer. These complexes join end-on-end to form filaments, and mutations in the terminal end subunit (Cdc11) prevent polymerisation and cytokinesis. It is not known how these octamers are assembled. In this thesis, I examine two aspects related to the structure of septins. In the first structural study, I show that septins form initial dimers at the G interface, which then permits NC interactions. This implies that the strongest G interface septin dimers might specify how octamers might be assembled. In the second structural study, I examine the positional arrangement of mammalian septins within a putative octamer. I show that Sept9 is a terminal septin subunit such that a putative mammalian septin octamer is arranged as Sept9-Sept7-Sept6-Sept2-Sept2-Sept6-Sept7-Sept9. Similar to yeast, I find that a mutation in the terminal end subunit (Sept9) prevents septin polymerisation and cytokinesis. Finally, I examine the role of septins in cells with primary cilia, an antennae-like cellular protrusion that act as efficient signaling organelles. I show that septins might regulate RhoA signaling at the base of cilia by binding and activating a RhoGEF, ArhGEF18. Collectively, my findings provide a step forward in understanding mammalian septin biology.

Keywords: Primary Cilia
RhoA activation
Septins
Advisor: Trimble, S William
Communication in Large-scale Brain Networks: Theory and Application

The complex connectivity of the cerebral cortex suggests that inter-regional communication is a primary function. The present body of work represents an effort to establish a conceptual and methodological framework in which to study integration and communication in brain networks.Studies 1 and 2 describe a time series analysis method that utilizes time-frequency fluctuations of neural activity to infer how information is integrated by individual nodes of the network. Study 1 develops the method and demonstrates how it can be applied to resting-state EEG recordings. I show that the method is sensitive to changes in cognitive state and that it is capable of discriminating between eyes-open and eyes-closed recordings. In Study 2, the method is applied to a developmental MEG data set, in which participants performed a face processing task. Processing of upright faces was associated with a small number of sustained integrative episodes in right fusiform gyrus. When faces were inverted, face processing was fractured and associated with a larger number of shorter integrative stages. Studies 3 and 4 describe a platform to simulate communication in large-scale brain networks. An anatomically realistic structural network was implemented as a dynamic system in which units of information flow along white-matter projections. Study 3 investigates how structural connectivity influences the efficacy of communication. I show that the topology of brain networks appears to be organized in a way that prioritizes speed of information transmission, rather than reliability and total throughput. In addition, I demonstrate that the rich club of hub nodes is a critical topological feature that governs how signal traffic is distributed in the network. Study 4 explores the role of a particular node: subfield CA1 of the hippocampus. I show that, despite the fact that CA1 does not appear to be important from a topological perspective, in the context of networked communication it is one of the most important nodes in the brain and acts as a convergence zone for signal traffic. Altogether, these data demonstrate the utility of models that embody the notion of communication and how such models offer novel and unique insight into brain structure and function.

Keywords: communication
information
multivariate
network
queueing
rich club
Advisor: McIntosh, R Anthony
Design and Development of Multi-directional Dual-beam Piezoelectric Energy Harvesters

The demand for powering small electronics has stimulated the development of vibration energy harvesting. Among several transduction mechanisms that can convert vibration into electrical energy, piezoelectric transduction has received the most attention. A conventional piezoelectric energy harvester is a cantilever beam with piezoelectric layers attached in a unimorph or a bimorph configuration. The conventional piezoelectric energy harvester has the advantages of compactness and simplicity in design. However, it suffers from a narrow bandwidth and uni-directional sensitivity. The narrow bandwidth indicates that a conventional piezoelectric energy harvester can only scavenge sufficient energy at a specific frequency and the uni-directional sensitivity means that the harvester can only work efficiently when the excitation is in the transverse direction of the beam. These two major issues limit the applications of piezoelectric energy harvesting. To overcome the narrow bandwidth, a V-shaped piezoelectric energy harvester and four magnet-integrated piezoelectric energy harvesters were designed, theoretically modeled, and numerically or experimentally validated. The V-shaped piezoelectric energy harvester is composed of two sections of beam and tip masses attached to the ends of the two sections. An analytical linear model was derived and validated with a finite-element-method model. The results show that the V-shape design can have the first resonant frequencies closer than a conventional design. The angle between the two sections significantly influences the first two resonant frequencies. Besides the linear method, a magnet-integrated dual-cantilever piezoelectric energy harvester was also designed and developed. The dual-cantilever harvester consists of two cantilever beams with magnets attached to couple the two beams. A theoretical model was derived and verified with experimental results. Significant improvement in bandwidth is shown in the result. Moreover, multi-directional energy harvesters were designed and developed to overcome the issue of uni-directional sensitivity. These multi-directional energy harvesters consist of a main piezoelectric beam and one or two auxiliary subsystems. The auxiliary subsystems were theoretically and experimentally proven to enhance the functionality of the harvesters for multi-directional broadband energy harvesting.

Keywords: Energy Harvester
Piezoelectric
Vibration
Advisor: Zu, Jean
A Synthetic Biology Application in Metabolic Engineering

Since the 1970s, bioprocess engineering has focussed on the optimization of the production of chemicals via biological transformations. In particular, much emphasis has been placed on estimating the optimal process variables to maximize the production of the desired chemical. Notably, engineers were limited to using macroscopic process variables, such as the feed rate of the bioreactor. Optimization involves the trade-off between productivity and yield. High values of both metrics are required for a viable plant; however, the two metrics are in competition. Recently, the emergence of synthetic biology has enabled bioengineers to extend the optimization of bioprocesses from the macroscopic level to the genetic level. With this in mind, we propose a novel synthetic biology approach for bioprocess optimization. Our case study involves a lactic acid-producing Escherichia coli strain with the adh (alcohol dehydrogenase) and pta (phosphotransacetylase) genes deleted. Deletion of these genes increases the yield of lactic acid; but, at the same time, growth rate and productivity decrease drastically. Initially, we introduce the model-based design of an integrated genetic circuit that links a density sensory mechanism to a dynamic genetic controller, and subsequently to bacterial metabolism. In this way, the genetic circuit dynamically controls genes that contribute to growth and productivity. Then, we conduct a mathematical analysis of the model to help us in the initial design and further optimization of the integrated circuit. The analysis can minimize the time required to design and troubleshoot the genetic circuit. Also, the analysis showed that the induction time is the most important process variable we can optimize. Finally, we carried out experimental results in an attempt to utilize the genetic toggle switch as a controller to manipulate genes adh and pta in an ON-OFF fashion. While we expected to observe some growth restoration and productivity improvement, it is common for synthetic biology constructs to behave differently in different environments or strains. Indeed, the experimental results show that our assumption that the genetic toggle switch will restore wild-type levels of adh-pta expression may not be true. In summary, this work introduces a novel synthetic biology approach for the optimization of bioprocesses and attempts a proof of concept implementation of the strategy. Although, the initial implementation was not successful, we have done some troubleshooting with respect to the problems involved and suggestions are given for future experiments.

Keywords: bioprocess optimization
dynamic control
metabolic engineering
quorum sensing
synthetic biology
toggle switch
Advisor: Cluett, R William
Polymeric Micelles as a Diagnostic Tool for Image-guided Drug Delivery and Radiotherapy of HER2 Overexpressing Breast Cancer

Block copolymer micelles have emerged as a viable formulation strategy with several drugs relying on this technology in clinical evaluation. To date, information on the tumor penetration and intratumoral distribution of block copolymer micelles (BCM) has been quite limited. Thus, there is impetus to develop a radiolabeled formulation that can be used to gain invaluable insight into the intratumoral distribution of the BCMs. This information could then be used to direct formulation strategies as a means to optimize treatment outcomes. This thesis describes the synthesis and characterization of a targeted block copolymer micelle system based on poly(ethylene glycol)-block-poly(ε-caprolactone) labeled with the radionuclide Indium-111 (

Keywords: Breast Cancer
Drug Delivery
Imaging
Nanotechnology
Radiotherapy
Advisor: Allen, J Christine
Ancient Greek Cult Hymns: Poets, Performers and Rituals

This dissertation looks at the interplay between the poetic text and the circumstances of production in the performance of Greek cult hymns. Although it employ the evidence from various genres and performance occasions, including the Homeric, Orphic and dramatic hymns, the primarily focus is those hymns that were composed to accompany religious rituals and are fully integrated into a public cult event. These include the well-known fragmentary lyric works of Archaic and Classical poets such as Alcman and Pindar as well as inscribed hymns.The investigation looks at the groups and individuals involved in the production of cult songs and show how their interests and goals helped shape the performed text. A key premise of the study is that no single function can explain the entire extant corpus of such hymns, but rather, in order to delineate a network of relevant stakeholders, each hymn must be considered in its own particular historical and performative contexts. The principal rhetorical-religious aim of a hymn is to praise a deity in an appropriate manner. One of the greatest challenges for an ancient hymnographer was to balance between this primary goal of a hymn and various other competing functions specific to the occasion. For this to be achieved, the text needed to employ the familiar form and language of Greek hymnodic tradition, allowing it to maintain a feeling of a genuine religious song. Yet this constraint left ample room for the poet to manipulate traditional material and generic forms in a manner that would reflect the interests of mortal stakeholders. It is this manipulation of traditional form to accommodate the specific circumstances - particularly the various stakeholders - of the particular hymnodic occasion that is the principal interest of this thesis.

Keywords: ancient hymns
ancient ritual
Greek cult hymn
Greek religion
lyric performance
religious songs
Advisor: Revermann, Martin
Mechanical Behaviour of Cold-formed Hollow Structural Section Material

In this thesis, the static and dynamic properties of cold-formed Rectangular Hollow Sections (RHS) produced by different manufacturing techniques (direct-forming versus continuous-forming; heat-treated versus non-heat-treated) were studied comparatively for the first time. The aim of this research was to quantify the effects of different manufacturing processes on the mechanical behaviour of RHS such that the implications of using RHS with different production histories can be better appreciated during the design of structures made of RHS and their welded joints.The static properties of seven cold-formed RHS specimens were investigated by performing tensile coupon tests, stub column tests, and residual stress measurements. Analytical column curves were generated to reflect their compression behaviour, based on the experimental results. It was found that, in general, the static properties of a direct-formed RHS are midway between those of its continuous-formed and continuous-formed plus heat-treated counterparts.The Charpy V-notch (CVN) impact toughness properties of six RHS specimens were studied via 378 CVN coupons. For RHS with different cross-sectional geometries and produced by different methods, complete CVN toughness-temperature curves of the flat face and the corner were compared to quantify the decrease of notch toughness from the flat face to the corner due to uneven degrees of cold-forming. It was also found that heat treatment in accordance with Canadian standards for "Class H" finishing does not provide improvement in the CVN toughness.The high strain rate properties (compressive and tensile) of four RHS specimens manufactured by different cold-forming methods were examined by performing a total of 166 split Hopkinson pressure/tension bar tests at strain rates ranging from 100 to 1000 s-1. Their dynamic yield stresses were compared to their static yield stresses, to characterize the strength enhancement of cold-formed RHS under such loading rates, which can be used in the blast- or impact-resistant design of RHS members.

Keywords: Charpy V-notch impact toughness
continuous-formed
direct-formed
high strain rate behaviour
Rectangular Hollow Section
static properties
Advisor: Packer, A Jeffrey
Dynamic Optimization Addressing Chemotherapy Outpatient Scheduling

Chemotherapy outpatient scheduling is a complex problem containing uncertainty. Chemotherapy centres are facing increasing demands and they need to increase their efficiency. However, there are very few studies looking at using optimization methods on the chemotherapy scheduling problem.In this dissertation, the chemotherapy outpatient scheduling problem is defined within the scheduling literature. Next, we propose a methodology for choosing what information to include from the problem domain when creating a mathematical model of a real world problem. Several constraint programming models, representing different problem definitions of the deterministic chemotherapy scheduling problem, are created and evaluated for their solvability and the quality of their solutions. The chosen optimization model was tested within a dynamic framework in order to accommodate the dynamism and uncertainty inherent in chemotherapy outpatient scheduling. Termed dynamic template scheduling, this novel algorithm uses the chemotherapy centre's past records and the chosen model to create a template of open slots. As requests for appointments arrive, we use the template to schedule them. When a request arrives that does not fit the template, we update the template. To accommodate last minute additions and cancellations to the schedule, we test a shifting algorithm that moves patient start times within a predefined time limit. We demonstrate that chemotherapy centres can use records of past appointments to inform future schedules and that integrating optimization methods into the scheduling procedures can improve efficiency and increase throughput. This research makes a contribution to scheduling research by developing a novel technique that combines proactive and reactive scheduling to address dynamic problems with real-time uncertainty. This research also makes a contribution to health care scheduling applications by solving a case of chemotherapy outpatient scheduling, a practically important problem that has had very little treatment in the literature.

Keywords: Chemotherapy
Constraint Programming
Healthcare
Optimization
Scheduling
Uncertainty
Advisor: Carter, W. Michael
The Business of Schooling: Marketing in Canadian Independent Schools

This study explores the response of school administrators to the rapid infusion of marketing and business ideals and practices into the Canadian independent school system. As a mixed-methods study, a survey of CAIS schools (Canadian Association of Independent Schools) provides an environmental scan of marketing approaches across the country, while three in-depth case studies provide specific detail about how administrator responses play out at specific school sites. Five approaches to school marketing emerge from the survey, ranging from strongly welfarist to strongly new managerial. An exclusively business-oriented approach exists opposite to welfarism on the continuum, but was not observed in this study. School placement along the continuum is largely determined by the school's local competitive market. Schools in markets characterized by low levels of competition tend to encourage a welfarist approach to school leadership while highly competitive markets tend to support a new managerial approach. Case study schools were selected to represent different marketing approaches, and findings support the correlation between market competition and continuum positioning. The professional biographies of school administrators, in particular Heads of schools, were also found to correlate with the observed marketing approach. The existence of a continuum of approaches to independent school marketing, and in particular the placement of competitively-based schools along this continuum, likely has implications for stakeholders. This study raises questions about the consequences for students, parents, teachers and administrators resulting from the shift from welfarism to new managerialism observed in highly competitive markets.

Keywords: independent schools
International Baccalaureate
marketing
new managerialism
school choice
welfarism
Advisor: Bascia, Nina
The Impacts of Climate Change on Potential Permafrost Distributions from the Subarctic to the High Arctic Regions in Canada

A climate change impact assessment on the potential permafrost distributions is presented in four research studies that was conducted using various locations along a geographical south-to-north study transect from 52.2°N to 82.5°N within Canada. The transect begins in Lansdowne House, Ontario, and ends at Alert, Nunavut, with intermediate locations at Big Trout Lake, Peawanuck, Fort Severn, Rankin Inlet, Resolute Bay, and Eureka. The first study established the climatic potential for permafrost at Peawanuck from 1959-2011 using the Stefan Frost (Fs) Number index and Stefan equation for active layer thicknesses. Fs and the Stefan depths demonstrated favourable potential for permafrost; however, freezing degree-days were observed to be declining. The second study examined active layers developments at five locations from 2004-2011 using the Xie-Gough Algorithm for multilayered soil profiles. Climate conditions for potential permafrost distributions were assessed and compared using Fs. The third study explored the changes in the potential permafrost using Fs under future climate warming scenarios projected by an ensemble of Global Climate Models for 2011-2100. Climate change projections within the transect indicate warming above the 1971-2000 mean air temperature baseline by +1.5 to +2.4°C for 2011-2040; +2.6 to +4.1°C for 2041-2070; and +3.3 to +7.1°C for 2071-2100. For this century, Fs projections indicate that climate conditions will remain supportive for continuous permafrost distributions at Resolute Bay, Eureka, and Alert. By 2040, conditions for Rankin Inlet indicate change from continuous to discontinuous permafrost. For Peawanuck, conditions by 2100 are projecting to be suitable for sporadic permafrost. The fourth study focuses at Peawanuck and three other locations within northern Ontario, and assessed the behaviour of palsa formation and occurrence in the context of climate change for the 2020s, 2050s, and 2080s. By the end of this century, warming projections support palsa occurrence; however, conditions will no longer support new palsa formation.

Keywords: Active Layer
Arctic
Climate Change
Climate Modelling
Palsa
Permafrost
Advisor: Gough, William A