title: Characterizing immunomodulatory activity of lactic acid bacteria on cell types involved in innate immunity: analysis of the effects of Lactobacillus rhamnosus R0011-derived milk ferments on macrophage polarization and of secretome effects on intestinal epithelial cell cytokine production

subject:
Secretome
Lactobacillus rhamnosus R0011
Lactobacillus helveticus R0389

abstract: Probiotic lactic acid bacteria have been associated with a wide array of host-immune modulatory effects including down-regulation of pro-inflammatory gene transcription and expression following pro-inflammatory challenge, through direct and indirect contact with host immune cells. However, it is still unknown how many of these microorganisms convey these beneficial immune effects to the host. Lactobacillus rhamnosus R0011 and Lactobacillus helveticus R0389 were examined for their immunomodulatory activity on challenged human HT-29 and rat IEC-6 intestinal epithelial cells (IEC). Secreted products from both strains demonstrated the ability to down-regulate IL-8 production from challenged HT-29 with differential effects on CINC-1 production from challenged IEC-6 cells. Further, L. rhamnosus R0011-derived milk ferments were tested for their ability to modulate pro-atherogenic cytokine production from challenged human THP-1 and U937 monocytes and macrophages. Culturing THP-1 and U937 macrophages with milk ferments resulted in the up-regulation of regulatory cytokine production in response to challenge with lipopolysaccharide indicating possible polarization into the regulatory M2b macrophage phenotype. Taken together, L. rhamnosus R0011 has been shown to have immunomodulatory activity on a variety of cells involved in innate immunity.


title: A framework of image processing for image-guided procedures

subject:
Image processing
3D image registration
Segmentation
Surface reconstruction
Moments invarient

abstract:
Contrary to the cases of open surgery, during minimally invasive procedures,
surgeons have no direct access or very limited access to the operative site and
can only visualize the site and the focal region with the aid of imaging tools.
During patient follow-up and the surgical planning stage, multiple complementary
images and patient-specific models need to be aligned with each other for
better interpretability. Image segmentation and deformable image registration
are often needed for this step since the tissues normally deform in different images.
Traditionally, image segmentation and registration are separate research
topics. However, they are closed related. Segmentation accuracy affects feature based
registration accuracy and a good registration is able to improve the speed
and accuracy of image segmentation.
In this thesis, we present a coherent and consistent framework for image
processing. The process of the proposed approach consists of two main modules.
In the first module, we performed preprocessing tasks on raw MR images
to extract the blood vessels centerlines from these images. Next, bifurcation
points were calculated as the intersections of the extracted centerlines. Vessel
structures and bifurcation points provide input information for further operations
such as image segmentation and image registration. Then, we propose an
innovative approach to automating the initialization process of the liver segmentation
of magnetic resonance images. The seed points, which are needed to
initialize the segmentation process, are extracted and classified by using affine
invariant moments and artificial neural network. To complete this stage, we
proposed robust and fast approaches for MR image registration for deformable
tissues. The proposed registration methods work with soft homogenous tissue
with small and large rotation shift.
In the second module, we performed surface to surface registration of MR
and endoscopic images, which will provide the surgeon with better 3D context
of the surgical site in minimally invasive procedures. In this step, we project
a gridline light pattern onto the surgical site and then use a stereo endoscope
to acquire two stereo images. The major steps in the surface reconstruction
process include 1) applying an automatic method of detecting region of interest,
2) applying an image intensity correction algorithm, and 3) applying a
novel automatic method to match the intersection points of the gridline pattern.
We have validated our proposed framework technique by comparing the
methods with existing techniques of similar scope. Our experiment results show
that our methods outperform the existing methods regarding correctness and
efficiency.

abstract: University of Ontario Institute of Technology


title: Exploring the intersection of bi-cultural identity, social networking and a multiliteracies pedagogy on English language learning

subject:
Multiliteracies
Digital tools
English language learner
Social networking
Bi-cultural identity

abstract: The aim of this qualitative research study was to examine the construction of adolescents’ bi-cultural identities through an exploration of their social practices on the social networking site, Ning. Specifically, I ask: what is the impact of participating on a social networking site (SNS) on (1) the language and literacy skills of grade six English Language Learners (ELLs)?; (2) the development of ELLs’ bi-cultural identities?; (3) social presence for ELLs in the classroom learning community? The collaboration witnessed in the classroom as a result of the digital tools, and the implementation of a multimodal platform for students to perform their identities and to connect with one another ultimately had a positive impact for the ELLs. These students made gains in their language and literacy skills, sense of bi-cultural identities and in their social presence in the classroom.


title: Environmental impact of zebra mussel controls in nuclear power plants

contributor:
McKellar, Jennifer
Harvel, Glenn

subject: Nuclear Environment Mussel Control LCA

abstract: Industries that rely on the Great Lakes for cooling have battled the zebra mussel infestation for years. With increasing emphasis on environmental sustainability, decision-makers need to consider more than just monetary cost. This work compares two methods of zebra mussel control that are used in Nuclear Power Plants (NPP), chlorine and ozone, through life cycle assessment. The GHGenius model was used to estimate greenhouse gas (GHG) emissions from each life cycle stage, from control agent production, through delivery, to end use of each method. The goal of the study is to estimate the amount of GHG produced per unit of water treated. While GHG analysis does not portray the entire picture for environmental impacts, it can be used to help future operators select a more environmentally friendly solution to zebra mussel control. For large NPPs, chlorination was found to perform better. Other considerations need to be considered for smaller reactors.


title: Effect of copper contamination at the cathode in Cu-Cl electrolyzers for hydrogen production

subject:
Hydrogen
Cu-Cl/HCl thermochemical cycle
Proton-pump
Electrolysis

abstract: In this work the effects of copper contamination on the coulombic and voltage efficiency of the hydrogen evolution reaction (HER) via the Cu-Cl thermochemical cycle are investigated. A novel proton pump configuration was employed, which allowed for the copper concentration at the cathode to be controlled. A variety of electrochemical tests were performed to evaluate the effect of copper on the system. The purpose of this research project was to determine the threshold for copper contamination at the cathode in these Cu-Cl/HCl electrolyzers. Results of electrochemical test show that there is a significant increase in overpotential and a negative impact on HER kinetics with increasing copper concentration in both a chloride rich and chloride-free environment. In both media the Coulombic efficiency remains constant regardless of the concentration of copper in the catholyte. Results suggest that when the concentration of copper is greater than 5 ppm, the effects of copper contamination becomes significant.


title: Joint optimization of transmit beamforming and base station cache allocation in multi-cell C-RAN

contributor:
ShahbazPanahi, Shahram
Dong, Min

subject:
Cloud radio access networks (C-RAN)
Beamforming
Cash allocation
Wireless backhaul
Zero-forcing (ZF)

abstract: Cloud radio access network (C-RAN) with wireless backhaul has been considered as a possible solution for small cell deployment. Limited capacity of wireless backhaul encourages people to equip the base stations (BSs) with cache storages to mitigate peak-time data traffic. We study a downlink C-RAN consisting of a central processor (CP) and multiple cache-enabled BSs connected to the CP through wireless backhaul links. Through joint optimization of beamforming and cache size allocation, we aim to distribute cache sizes among BSs such that long-term delivery time of files is minimized. Assuming zero-forcing (ZF) beamforming is adopted at CP, cache size allocation problem becomes convex which can be solved by convex optimization techniques. Simulation results show that loss of optimality due to ZF assumption is negligible for large antenna sizes at CP. Moreover, the superiority of our proposed caching scheme over several heuristic ones, including proportional caching, is demonstrated by simulation.


title: Baseline comparability to accelerometry data and changes in standing balance over the course of an athletic season using a postural sway assessment tool

contributor:
Murphy, Bernadette
Holmes, Michael

subject:
Balance
Concussion
Postural sway
Baseline testing
Post-concussion

abstract: Changes in balance ability can be a sensitive measure of post-concussion changes in brain function. However there is a need to determine the most reliable, valid and practical ways to assess balance abilities (i.e. degree of postural sway). The Sway Balance™ System is a mobile software application that uses the tri-axial accelerometer located within an iOS device to quantify thoracic sway. The software relies on comparing the individual’s post-concussion score to baseline scores obtained at the start of an athletic season. However, in youth athletes in particular, balance may change over the course of the season, worsening due to factors other than concussion, such as lower limb injuries, or improving as fitness improves. This study first compared baseline Sway Balance™ scores to the industry standard accelerometer data recorded from the sternum and attached externally to the iOS device in an elite youth (aged 16 to 20) lacrosse team. We found that balance scores derived from Sway Medical’s algorithm had moderate to very strong validity when compared to laboratory accelerometers. We then assessed the reproducibility of the Sway Balance™ System at 5 and 10 weeks relative to baseline. Correlations ranged from weak to excellent depending on which weeks were compared. Variations were observed in some of the athletes’ balance scores over the 10 weeks, and in overall group differences at different measurement points. This work indicates that while software such as the Sway Balance™ System has the validity to act as a balance measure, there is considerable work needed in protocol development to ensure that a change in score genuinely reflects a change in balance in concussed athletes.


title: Rapid rotational foam molding of polyethylene integral-skin foamed core moldings

subject: Plastic processing technology

subject: Rapid Rotational Foam Molding

subject: Polyethylene integral-skin foamed core moldings

abstract:
This thesis focuses on the design, development, and evolution of a novel patent-pending
plastic processing technology entitled “Rapid Rotational Foam Molding” with special
emphasis on the processing of polyethylene (PE) integral-skin foamed core moldings.
Rapid Rotational Foam Molding is a technology deliberately designed to address the
intrinsic disadvantage of conventional rotational foam molding, i.e., its very long cycle
times. In this context, a physical system that exploits the positive synergistic effects of
innovatively combining extrusion melt compounding and rotational foam molding was
designed and built. The fundamental processing steps of this system comprise (i)
rotationally molding a non-foamable PE powder in a lab-scale oven while, (ii)
simultaneously melt compounding and foaming a pre-dry blended foamable PE and
chemical blowing agent (CBA) formulation in an on-line lab-scale extruder, and then (iii)
filling the newly created foaming material into the non-chilled hollow article thereby
created in the mold through a special interface.
Two varieties of PE resins ranging from linear low density PE (LLDPE) to high
density PE (HDPE) were selected for experimentation with melt flow rates (MFR)
ranging from 2.0 to 3.6 g/10min. The implemented CBA was Celogen OT. The
materials were characterized using thermal analysis techniques such as differential
scanning calorimetery (DSC) and thermogravimetric analysis (TGA) to ensure their
correct operating temperatures ranges. Scanning electron microscopy (SEM) was utilized
for characterizing the quality of the foam samples and achieved skin-foam interface for
the final moldings. Improvements to the achieved molding quality were accomplished
through various system and process modifications described throughout this research
work.


title: A few randomized protocols in peer-to-peer networks

subject: Random Algorithms

abstract: This thesis studies a few randomized algorithms in application-layer peer-to-peer networks. The significant gain in scalability and resilience that peer-to-peer networks provide has made them widely used and adopted in many real-world distributed systems and applications. The unique properties of peer-to-peer networks make them particularly suitable for randomized algorithms such as random walks and gossip algorithms. We study these by developing implementations based on the Docker virtual container technology. We can thus analyze their behaviour and performance in realistic settings. We further consider the problem of identifying high-risk bottleneck links in the network with the objective of improving network reliability. We propose a randomized algorithm to solve this problem and evaluate its performance by simulations.


title: Power-optimal network beamforming in single-carrier asynchronous two-way relay networks

contributor:
Grami, Ali
ShahbazPanahi, Shahram

subject:
Cooperative wireless communications
Asynchronoous two-ray relay networks

abstract: In this thesis, we consider a single-carrier asynchronous two-way relay network, where the relays employ amplify-and-forward (AF) signaling in a multiple access broadcast channel (MABC) protocol to enable a bi-directional communication link between two transceivers. The network we consider is asynchronous, meaning that each relaying path (which originates from one transceiver, goes through one of the relays, and ends at the other transceiver) causes a delay which is significantly different from the delays caused by other relaying paths. Such a two-way relay channel can be viewed as a multi-path link which can produce inter-symbol-interference at the two transceivers. Assuming a block transmission scheme, we resort to cyclic prefix insertion to eliminate inter-block-interference. We aim to obtain the relay complex beamforming weights and the transceivers’ transmit powers such that the total power consumed in the whole network is minimized subject to two constraints on the transceivers’ data rates. We rigorously prove that at the optimum, only a subset of the relays has to be turned on and the rest of the relays have to be switched off. More specifically, we prove that at the optimum, the end-to-end channel impulse response (CIR) will have only one non-zero tap, and hence, only those relays which contribute to that non-zero tap have to be turned on. We devise a simple search algorithm to optimally determine which tap of the end-to-end CIR has to be non-zero. Finally, we present a semi-closed-form solution for the optimal values of the design parameters, namely the relays’ beamforming weights and the transceivers’ transmit powers. Our simulations results show that our proposed method significantly outperforms an equal power allocation scheme (i.e., when all the nodes in the network consume the same amount of power) which satisfies the same constraints on transceivers’ data rates.


title: Determining the effectiveness of nuclear security through computer simulation

subject: Modeling Simulation Security STAGE Monte-Carlo

abstract:
There is a growing concern from both national regulators and the International
Atomic Energy Agency (IAEA) about the threat posed by attacks against iconic targets such as nuclear power plants. This has led to an increased desire to be able to objectively measure the effectiveness of the physical security of these sites to prevent theft or sabotage of the nuclear and radiological material. Currently verification of physical protection systems is done using subjective expert opinion as well as time consuming and expensive live exercises. A method that allows experts to design and test a facility in the absence of live action exercises using larger sample sizes would be highly desirable. To _ll the niche a synthetic environment model was designed around the force on force simulation program STAGE to allow the full 3-D simulation of a nuclear facility. This allows for simple user modifications to the model, allowing many scenarios to be tested. Many detectors were added to more accurately reflect the types of sensors present at a nuclear facility. Having modeled the facility and the probabilities associated with various events, Monte-Carlo methods were applied to obtain statistics on how effective the guard force was at stopping the adversarial force. This technique can be used to give experts more robust, simple to use tools for the design and verification of physical protection systems.


title: Mathematical methods for 2D-3D cardiac image registration

subject:
Image registration
Inverse problems
Slice-to-volume registration model
Cardiac MRI
2D to 3D alignment

abstract:
We propose a mathematical formulation aimed at intensity-based slice-to-volume registration,
aligning a cross-sectional slice of a 3D volume to a 2D image. The approach is
flexible and can accommodate various regularization schemes, similarity measures, and
optimizers. We evaluate the framework by registering 2D and 3D cardiac magnetic resonance
(MR) images obtained in vivo, aimed at image-guided surgery applications that
utilise real-time MR imaging as a visualization tool. Rigid-body and affine transformations
are used to validate the parametric model. Target registration error (TRE),
Jaccard, and Dice indices are used to evaluate the algorithm and demonstrate the accuracy
of the registration scheme on both simulated and clinical data. Registration with the
affine model appeared to be more robust than the rigid model in controlled registration
experiments. By simply extending the rigid model to an affine model, alignment of the
cardiac region generally improved, without the need for complex dissimilarity measures
or regularizers.


title: An experimental study of the relative response of plastic scintillators to photons and beta particles within the context of tritium monitoring

subject:
Plastic scintillator
Tritium
MCNP
Gamma photons
Beta particles

abstract: A scintillation counting system has been constructed with the use of BC-400 and EJ-212 series plastic scintillators along with a subminiature photomultiplier tube to investigate the effect of increasing plastic scintillator thickness on system-integrated counts. Measurements have been carried out using four different gamma sources with different energies ranging from 6keV to 1.332MeV and a Ni-63 beta source of maximum energy of 66keV. A simulation was also carried out in MCNP4a to verify the number of H-3 beta particles with max energy 18.6keV that would reach the plastic scintillator in a vacuum setting as well as in an air medium. Scintillator thicknesses ranged from 10μm to 2500μm. The response of the system was determined by measuring the integrated counts as a function of scintillator thickness. The results of these measurements showed the expected positive linear correlation between scintillator thicknesses and integrated counts for all the gamma sources while the slopes of the correlations of each gamma source was a function of the source energy. The beta particle response showed an initial increase of counts with scintillator thickness followed by a slight decrease. The MCNP simulation confirmed an analytical calculation of the fraction of H-3 beta particles for a given air concentration that would reach the scintillator. These results in conjunction with the experimental findings were used to assess the potential of a plastic scintillator system forming the basis of a tritium monitor for the detection of tritium in high-energy gamma backgrounds for Canadian nuclear power workers.


title: Design and analysis of a thermolysis reactor for scaled-up copper-chlorine hydrogen production cycle

subject:
Copper-chlorine
Thermochemical
Decomposition
Hydrogen production
Copper oxychloride

abstract:
Alternative hydrogen production methods are being explored with the goal of
finding efficient and economical process. The copper-chlorine (Cu-Cl) cycle for
hydrogen production has been the focus of the Clean Energy Research
Laboratory (CERL) at the University of Ontario Institute of Technology
(UOIT). The Cu-Cl cycle has lower thermal energy requirements compared to
other methods and utilizes waste heat from power plants and/or some
industrial processes. The cycle includes the electrolysis, hydrolysis and
thermolysis reaction steps. Decomposition of copper oxychloride (CuOCuCl2)
occurs in the thermolysis reactor between 480°C and 530°C. A thermolysis
reactor design is presented here with the purpose of scaling it up for a pilot
plant of the Cu-Cl process. Transient thermal simulations were conducted with
2.0kg of cuprous chloride (CuCl), single and dual heating sources, and 1, 2 and
4 Wm-2K-1 internal surface convection rates. The dual heater configuration
provided the required temperature distribution to allow decomposition to
occur. Experimental data with dual heat sources showed that surface
temperatures reached 531°C ± 14.0°C. Faster heating was observed with
granular CuCl in comparison to solidified CuCl, because the material was
allowed to mix in the reactor while it was melted. Simulations with 10.35kg
CuCl confirmed adequate surface temperatures for decomposition at low
convection rates. Fouling in the phase separation section was observed: XRD
analysis showed that the bottom was crystalized CuCl while the upper section
was a mixture of predominately CuCl2 dihydrate and CuCl. The vapor
production was due to temperatures exceeding 530°C at the CuCl-crucible
interface.


title: Facilitators and barriers to physical activity experienced and perceived by adults with intellectual disability

contributor:
Lloyd, Meghann
Balogh, Robert

subject:
Intellectual disability
Physical activity
Adults
Facilitators
Barriers

abstract: Adults with intellectual disability (ID) experience high rates of health conditions that can be prevented and improved through health-promoting behaviours; however, they engage in considerably low levels of physical activity, the reasons for which are often multi-faceted and not always self-evident. This study utilized qualitative phenomenological inquiry, grounded in both the interpretivist and transformative paradigms, to explore the perspectives of adults with ID (n=13) of facilitators and barriers to their physical activity. Two focus groups were guided by semi-structured interview questions. Thematic analysis produced four facilitator themes (Individual, Support, Programs, Resources) and three barrier themes (Internal, External, and Not Recognizing or Understanding Barriers). The results suggest that adults with ID face a number of facilitators and barriers to their physical activity, which often act in combination to influence participation. Understanding these factors can lead to the development and implementation of well-informed strategies to increase physical activity in this population.


title: The ecotoxicological effects of metformin and its metabolite, guanylurea, on Japanese medaka (Oryzias latipes)

abstract:
Human pharmaceutical waste threatens many natural processes of non-target aquatic organisms, through the introduction of such contaminants into the environment. Pharmaceuticals are a large and diverse groups of medicinal compounds that are used for the diagnosis, cure, mitigation, treatment, and/or prevention of diseases in humans and animals. In recent years, the occurrence and fate of pharmaceuticals in the aquatic environment have become an emerging issue in aquatic toxicology, with one of the most prevalent contaminants being the type-2 diabetic drug, metformin, and its metabolite guanylurea. Metformin and guanylurea have been measured in surface waters in the ng- μg·L-1 range. This study aimed to investigate the toxicological effects of metformin and guanylurea on Japanese medaka (Oryzias medaka).
A first experimental step was to determine the potential for uptake, bioaccumulation, and depuration of metformin in early-life stage (ELS) medaka using 14C-metformin. Results from this study showed that both embryo and larval medaka can take up, bioaccumulate, and successfully depurate metformin from the aquatic environment. Furthermore, egg chorion hardening (~6 hpf) prevented the uptake of metformin from by developing embryos.
Additionally, we show that waterborne exposure to metformin and guanylurea significantly impacted the growth metrics in ELS fish, showing that guanylurea caused growth retardation at exposure concentrations an order of magnitude lower that those required by the parent compound to exert similar effects. We sought to explain these growth effects by investigating potential alterations in the metabolome and gene expression of these exposed fish. Several metabolite abundances were altered by the exposure of medaka to 3.2 μg·L-1 metformin and 1.0 ng·L-1 guanylurea, which included metabolites associated with cellular energetics, fatty acid synthesis and metabolism, and polyamine synthesis. Metabolomic results were applied to select genes of interest for RT-qPCR analyses, and the expressions of critical genes involved in lipid metabolism were shown to be significantly affected.
Furthermore, a full 165 day life-cycle study assessing the effects of metformin and guanylurea alone, and in combination, was performed to determine potential population-level impacts of the compounds on Japanese medaka. While exposure to metformin and guanylurea alone, and in combination, did not significantly stunt the growth of medaka, exposure to the compounds did alter the production of important sex steroid hormones in both male and female medaka. However experimental treatments did not affect the production of the egg yolk precursor protein, vitellogenin. Interestingly, no significant effect on reproductive output was seen. Collectively, these results underscore the need for additional studies examining the effects of metformin and guanylurea on aquatic ecosystems. To our knowledge, this research is the first to investigate the effects of environmentally relevant concentrations of these compounds in this manner.


title: Rights or wrong? Perceptions of trans people among undergraduate students

subject:
Transgender
Transgender theory
Perceptions of trans people
Undergraduate perceptions

abstract: Transgender people are still facing discrimination and misconceptions regarding their lives and lived experience (Abraham, 2016; Clements-Nolle, Katz & Marx, 2006; Finkenauer et. al, 2012; Maclean, 2016; Pyne, 2011; Roussy, 2016). Few studies have examined public perceptions of transgender people. By surveying undergraduate students, this thesis hopes to examine perceptions of transgender people and trans rights. This thesis examines the discrimination and marginalization of trans people. Education about trans identities, rights and issues is crucial, and a study evaluating perceptions of university students at the Faculty of Social Sciences and Humanities is an important step towards research, as opposed to evidence-based policy development, that addresses gaps and deficiencies in education. Results of this survey reveal that the majority of respondents show understanding and support for trans people and trans rights. A notable number of respondents, however, show potential misunderstandings of trans people and trans rights, or hesitate to share a socially undesirable answer. This study can provide direction on future research that addresses gaps in education to foster better transgender awareness and understanding.


title: Tribological capabilities of carbon based nano additives in liquid and semi-liquid lubricants

subject:
rGO
Graphene
TiO2
Friction
Hybrid nano additive

abstract:
The growing population, the environmental challenges and limitations of nonrenewable resources have enforced researchers to improve the energy efficiency and reduce energy wastage in all industrial sectors including manufacturing and automotive. The significant losses in the automotive and manufacturing industries are associated with frictional energy between the mating surfaces. In addition, high frictional forces accumulate material removal rate which directly affects the service life, efficiency, and maintenance cost of the components. This results into loss of functionality and efficiency depletion of the systems. One of the possible solutions includes focusing on the refinement of tribological applications by researchers and industrial sectors. Along with that, rapid growth in nanomanufacturing industries has opened an enormous range of opportunities to enhance tribological capabilities of lubricants. Improved physical and chemical characteristics of the nanomaterials allowed them to be used for many applications including production of new generation of lubricants. In this study, applications of carbon based nanomaterial and hybrid nanoadditives to both liquid and semi-liquid lubricants have been investigated. This thesis is divided into three phases based upon the type of nano additive into the liquid and semi-liquid lubricants. In phase 1, three forms of reduced graphene oxides (rGO) were evaluated for the tribological application using four-ball tester at 0.01% concentration. All three forms of rGO were produced using modified hummers method; however, different filtration method and
synthesis time were used to vary the bulk densities and lattice structures of rGO nanoplatelets. In the second phase of this study, the best rGO nanoplatelets were further studied at three different weight concentrations to discover the optimum concentration to modify friction and wear preventive characteristics. In order to obtain precise results about friction and worn surface characterization, ball-ondisk tribometer was used in situ condition. In the last phase of this research, graphene nanoplatelets and titanium dioxide nanoparticles were used individually at three different concentrations. Furthermore, hybrid nanoadditives (graphene and titanium dioxide mixed in three different ratios) were tested in both liquid and semi-liquid lubricants. Apart from tribological evaluation, physical, chemical, and structural properties were evaluated in three phases using viscometer,  RPVOT, Fourier-transform infrared spectroscopy, electron microscopy (SEM and TEM) and Raman spectroscopy.


title: Examining the utility of pre-charge youth diversion programs: a Canadian context

contributor:
Cesaroni, Carla
Ammar, Nawal
Zaidi, Arshia

subject:
Youth diversion
Net widening
Selection bias
Labeling theory

abstract: Despite the perceived benefits of pre-charge diversion programs, some researchers contend that programs based on police selection may suffer from selection bias. Critics have also argued that diversion programs are being used as a coercive tool to expand the number of youth into the justice system. Using police data from a local police service (N= 6479) in Ontario Canada, this thesis conducts a bivariate analysis to explore the personal characteristics of youth and attempts to determine the probability of being charged or diverted for minor youth offences. Results suggest implementation of the formal pre-charge diversion program had an impact on the police service‘s charging decisions.

abstract: University of Ontario Institute of Technology


title: Partial separation of an azeotropic mixture of hydrogen chloride and water and copper (ii) chloride recovery for optimization of the copper-chlorine cycle

contributor:
Rosen, Marc
Pope, Kevin
Jianu, O.A.

subject:
Azeotrope
Copper-chlorine cycle
Distillation
Hydrogen

abstract:
An atmospheric-pressure distillation system is designed and constructed to partially separate hydrochloric acid and water. The system concentrates HCl(aq) between the electrolyzer and hydrolysis steps of the Copper-Chlorine (Cu-Cl) cycle. Thus, the system
partially recycles HCl(aq), thereby decreasing the total operating cost of the cycle. The separation is only partial, as the mixture is unable to cross the azeotrope with only a single pressure. The distillation system consists primarily of one packed distillation column, which employs heating tapes and thermocouples to achieve a desired axial temperature profile. The column can be operated in batch or continuous mode.  After performing physical distillation experiments, it is found that feeds less than azeotropic concentration are separated into H2O(l) and highly-concentrated HCl(aq) (albeit at less than azeotropic concentration). Feeds greater than azeotropic concentration are not investigated as they are extremely corrosive (rich in HCl) and would likely destroy the apparatus. Corrosion product is prevalent in the bottoms product; it is a source of error that is partially mitigated by filtration. No correlation is found between feed concentration and output concentration. That is, the distillate is H2O(l) and the bottoms is HCl(aq) near azeotropic concentration; as long as the feed concentration is any value less than azeotropic. In other words, the degree of separation is found to be independent of the feed concentration, for feed concentrations less than azeotropic. The bottoms concentration varies from experiment to experiment,
but does so randomly, likely the result of corrosion impurities affecting the calculation of
its concentration. A simulation of pressure-swing distillation (PSD) is also performed to help determine the feasibility of HCl-H2O separation and the degree of separation. Furthermore, an investigation into metastability and its effect on the crystallization of CuCl2 from HCl(aq)
solutions is presented in Chapter 4.


title: Dynamic square patterns in two dimensional neural fields

subject:
Mean field modelling
Dynamic Turing bifurcation
Normal form analysis
Numerical continuation
Periodic orbits

abstract: The goal of this thesis is to study the emergence of spatiotemporal waves in neural field models. Neural field models aim to describe the activity of populations of neurons at a mesoscopic scale, considering averaged neuronal states dependent on continuous space and time. Mathematically, they are composed of spatial and temporal integral operators on domains of anatomical interest. The cortex is modelled as a two dimensional sheet, and under physiological assumptions for the spatial extent of connectivities, it is shown when the principal transition from resting to active states will result in the formation of waves. This thesis starts with a derivation for the integral operators from a physiological viewpoint. The notion of a dynamical system is then introduced, and theory relevant to the spontaneous emergence of activity is discussed. The thesis progresses to applying the dynamical systems view to neural fields, leading to an understanding of the transitions from inactive resting states to space dependent temporal oscillations - waves. For tractable analysis, the active states are restricted to have square periodic symmetry.


title: Using Rabin-Karp fingerprints and LevelDB for faster searches

subject:
Rabin-Karp fingerprints
Text search
LevelDB

abstract:
This thesis represents the results of a study into using fingerprints generated according to the Rabin-Karp Algorithm, and a database LevelDB to achieve Text Search times below GREP, which is a standard command-line UNIX text search tool.
Text Search is a set of algorithms that find a string of characters called a Search Pattern in a much larger string of characters in a document we call a text file.
The Rabin-Karp Algorithm iterates through a text file converting character strings into fingerprints at each location. A fingerprint numerically represents a window length string of characters to the left of its location. The algorithm compares the calculated fingerprint to the Search Pattern’s fingerprint. When fingerprints are not equal, we can guarantee the corresponding strings will not match. Whereas when fingerprints are, the strings probably match. A verification process confirms matches by checking respective characters.
Our application emerges after making the following major changes to the Rabin-Karp Algorithm. First, we employ a two-step technique rather than one. During step 1, the preprocessing step, we calculate and store fingerprints in a LevelDB database called an Index Database. This is our first major change unique to us. Step 2, the matching step, is our second unique change. We use the Index Database to look-up the Search Pattern’s fingerprint and gather its set of locations. Finally, we allow the pattern to be any length relative to the window length. We even created an equation to check if the difference in length is too long for the fingerprint’s number system base.
We facilitated our performance experiments by first building our application and testing it against GREP for a wide range of different parameters. Our conclusions and recommendations determine that although we currently only outperform GREP in about half the cases, we identify some promising opportunities to modify some parts of our application so that we can outperform GREP in all instances.


title: Rapid rotational foam molding of integral skin polypropylene cellular composites

subject:
Rapid Rotational Foam Molding
Integral-skin rotationally molded foams
RRFM
Chemical blowing agent
Polypropylene
Skin-foam interface
CBA

abstract:
Rapid Rotational Foam Molding (RRFM) is a novel patent-pending process that was
designed and developed to maximize the synergistic effects resulting from the deliberate
combination of extrusion and rotational foam molding and thereby serve as a time-andenergy
efficient technology for the manufacture of integral-skin rotationally molded
foams of high quality. This thesis presents a thorough study of the scientific and
engineering aspects related to the evolution of the RRFM process and its feasibility. This
innovative processing technology was assessed and verified through a battery of planned
experimental trials conducted utilizing an in-house custom-built industrial-grade lab-scale
experimental setup. The experimental trials involved a variety of polypropylene (PP)-
based foamable formulations with a chemical blowing agent (CBA) that were
compounded and processed by utilizing an extruder and then foamed and injected as a
foamed core, instantly, into the cavity of a suitable non-chilled rotationally molded
hollow shell made of non-foamed pulverized PP grades. The investigated mold shapes
included a cylindrical shaped mold and a rectangular flat shaped mold. The obtained
moldings were examined for the quality of the skin surface, the skin-foam interface, and
the achieved foam morphologies that were characterized in terms of foam density,
average cell size, and average cell density. Optimal processing parameters were
successfully determined for three different PP skin-foam formulation combinations. The
accomplished reduction in processing time and energy consumption by implementing
RRFM were substantial. A variety of processing impediments that hindered the efficiency
of the single-charge conventional rotational foam molding practice were resolved by
implementing RRFM; these include: the foam/skin invasion into the skin/foam layer of
the manufactured article and the premature decomposition of CBA during compounding
or subsequent rotational foam molding processing steps.


title: Expression of Arabidopsis thaliana cellulose synthase proteins and associated proteins in a Spodoptera frugiperda cell line

subject: Arabidopsis

subject: Cellulose synthase

subject: SF9

subject: DET3

abstract:
Understanding how cellulose synthesis occurs is key to understanding the
formation of the plant cell wall. This understanding could also be key to modifying
cellulose production to permit more efficient extraction of glucose from cellulose for the
production of biobased materials. Cellulose biosynthesis is carried out by cellulose
synthases; transmembrane multimeric processive glycosyltransferases responsible for
polymerizing UDP-glucose into glucan chains. Thirty-six glucan chains bind together in
parallel to form elementary cellulose microfibrils. Due to the essential nature of
cellulose synthases for plant survival and the recalcitrant nature of the cell wall to
chemical and enzymatic digestion, the cellulose synthases can be very difficult to
analyze by traditional approaches. In an attempt to circumvent some of the issues of
studying cellulose synthases, the cellulose synthase genes CESA1 and CESA3, along with
the cell wall associated genes COBRA, DET3 and POM1 were recombined into an
engineered Autographa californica nucleopolyhedron virus and expressed in Spodoptera
fruigiperda ovarian cells. Although recombinant protein could be detected for CESA1
and CESA3, C14-glucose incorporation on baculovirus infected cell lines have given
inconclusive results to the cellulose synthase activity of the CESA1 and CESA3 proteins.
With further optimization of the protein expression of CESA1 and optimization of the
variability in the C14-glucose incorporation assays, the baculovirus system may prove a
useful tool for studying the cellulose synthases.


title: Leadership based multi-objective optimization with applications in energy systems.

contributor:
Rahnamayan, Shahryar
Naterer, Greg F.

subject:
Multi-objective optimization
Multiobjective evolutionary computation
Metaheuristics
Hybrid energy systems design

abstract:
Multi-objective optimization metaheuristics (MOMs) are powerful methods for solving complex optimization problems but can require a large number of function evaluations to find optimal solutions. Thus, an efficient multi-objective optimization method should generate accurate and diverse solutions in a timely manner. Improving MOMs convergence speed is an important and challenging research problem which is the scope of this thesis. This thesis conducted the most comprehensive comparative study ever in MOMs. Based on the results, multi-objective (MO) versions of particle swarm optimization (PSO) and differential evolution (DE) algorithms achieved the highest performances; therefore, these two MOMs have been selected as bases for further acceleration in this thesis. To accelerate the selected MOMs, this work focuses on the incorporation of leadership concept to MO variants of DE and PSO algorithms. Two complex case studies of MO design of renewable energy systems are proposed to demonstrate the efficiency of the proposed MOMs. This thesis proposes three new MOMs, namely, leader and speed constraint multi-objective PSO (LSMPSO), opposition-based third evolution step of generalized DE (OGDE3), and multi-objective DE with leadership enhancement (MODEL) which are compared with seven state-of-the-art MOMS using various benchmark problems. LSMPSO was found to be the fastest MOM for the problem undertaken. Further, LSMPSO achieved the highest solutions accuracy for optimal design of a photovoltaic farm in Toronto area.
OGDE3 is the first successful application of OBL to a MOM with single population (no-coevolution) using leadership and self-adaptive concepts; the convergence speed of OGDE3 outperformed the other MOMs for the problems solved. MODEL embodies leadership concept into mutation operator of GDE3 algorithm. MODEL achieved the highest accuracy for the 30 studied benchmark problems. Furthermore, MODEL achieved the highest solution accuracy for a MO optimization problem of hydrogen infrastructures design across the province Ontario between 2008 and 2025 considering electricity infrastructure constraints.


title: E-fencing detection: mining online classified ad websites for stolen property.

subject:
E-fencing
Stolen property
Classification problem
Genetic algorithms
Rule extraction

abstract:
With the emergence of e-fencing, there presents a need to automate both the
detection of ads selling stolen property and the reporting process for victims. This thesis
presents a framework that dynamically retrieves and classifies online ads utilizing
artificial intelligence (AI) to minimize amount of domain knowledge required. Evaluating
these ads against existing known characteristics of theft as well as extracting new
characteristics from suspicious ads. This in conjunction with a reporting system allows
users to report events of theft and matches them to previously classified ads. The
framework was designed such that it would be domain portable and allow for rapid
adaptation to other domains. Experiments showed promising results, correctly classifying
single and multiple trend datasets, displaying anomalies in price histograms, and
extracting potential patterns that explain price variance. Experiments on other domains
highly susceptible to scams displayed unique results contradicting some fundamental
assumptions of the behavior of thieves.


title: Spatial and temporal assessment of rural-urban land-use gradient effects on water quality and periphyton communities in tributaries of Durham Region, Ontario

subject:
Land-use gradients
Spatial factors
Streams
Benthic algae
Water quality

abstract: This study examines the effects of longitudinal and local land-use gradients on water quality and periphyton within four watersheds representing varying rural-urban land-use types and intensities. Although numerous studies have identified how specific land-use gradients (e.g., urban or agricultural land-use) affect water quality and periphyton, it is not fully understood how varying intensities and types of rural-urban land-use gradients affect water quality and algae both within and across watersheds sharing similar physiography and climate. Therefore, this study aimed to determine how variation in rural-urban land-use gradients affect water quality and periphyton along the cumulative flow path of tributaries (i.e., longitudinal), as well as across tributaries where sites were approximately matched for distance from headwaters.  To assess spatial variation without the confounding effects of seasonality, I analysed water quality, algal biomass, and community composition from a set of algal growth substrates that were deployed in all study creeks (Lynde, Oshawa, Bowmanville and Soper) during May, 2015. Additionally, I examined the spatial and temporal variation of water quality and algal community structure in all tributaries from May – August, 2015.


title: Development of polymeric nano-composite fiber based structures for acoustics and filtration applications

contributor:
Pop-Iliev, Remon
Rizvi, Ghaus

subject:
Electrospinning
Sound absorption
Nanofibers
Filtration
Pressure drop

abstract:
Electrospinning lab-scale experimental set-up was developed for manufacturing polymeric nanofiber composites for acoustics and filtration applications. In this study, nanofiber membranes were fabricated using two types of polymer materials: Polyvinylpyrrolidone (PVP) and Polyvinylidene Fluoride (PVDF). The control parameters of the electrospinning process, including polymer concentration, voltage input, flow rate, needle to collector surface distance, and collector rotational speed, were studied and optimized using Taguchi’s experimental design methodology. The parametric study was performed to investigate the effect of varying the electrospinning variables on the fiber diameter, thickness, and weight of nanofiber membranes, respectively. Statistical models were developed for modeling and optimization of electrospinning parameters using Analysis of Variance (ANOVA), Response Surface Methodology (RSM), and Genetic Programming (GP). The experimental work examined and proposed in this thesis involves developing nanofiber membrane composites from a pure polymeric base, fillers, and layers for two different objectives, including low-frequency sound absorption and filtration applications.
Experimental results show that polymer concentration and voltage input were the two most significant parameters that regulate the fiber diameter, thickness, and weight of PVP and PVDF fiber membranes at high significance levels greater than or equal to 95%. Mathematical models developed using RSM show high average accuracies greater than 80% for the respective output responses. Empirical models developed using GP show higher accuracy than RSM models for all three responses generated from the electrospinning of PVP and PVDF fibers. The acoustic performance of the pure polymeric nanofiber composites with micro-scale thickness shows high sound absorption coefficient values close to one at different Back Cavities (BC’s) in the frequency range of 200-300Hz. Filler infused polymeric nanofiber composites show high coefficient values greater than 0.9 at even reduced thickness, compared to pure polymer fiber composites, in the frequency range of 300-500Hz at different BC’s. Electro-spun nanofiber membranes were developed from PVDF polymeric base and anti-viral /bacterial fillers for filtration applications. The layering of these nanofiber composites with surgical masks shows better particle filtration efficiency in the particulate size ranging from 0.3μm to 10.0μm with equivalent pressure drop level of N-95 masks.


title: Novel intelligent control techniques in solar-based energy harvesting systems

contributor:
Youssef, Mohamed
Wang, Ying

subject:
Photovoltaic
MPPT
DC-DC converters
Water pumps

abstract:
The sun is considered a precious source of energy. Much research has been done to increase our usage from solar energy since it is a renewable source and, most importantly, it is free and green. However in order to use solar panels "photovoltaic", it is important that we are getting the maximum power from the solar panels, which is very difficult and depends on factors such as solar intensity, temperature and the load itself. This is why Maximum Power Point Tracking (MPPT) controller is necessary to ensure that maximum power is delivered to connect appliances. Many MPPT algorithms have been developed with different accuracies and limitations. In this thesis, a novel algorithm is developed, implemented and a comparison is done with other algorithms. The results from the proposed system show fast tracking algorithm with a very small error.
The new algorithm has been applied to a solar-based water pump, which is a very important application. Water pumping can be implemented in different ways. If electrical energy is used for water pumping, the cost can be very high for areas, such as the rural and remote areas, where there is no conventional power grids. Solar-based water pumps offers a much needed alternative solution, which is easy to install, environmentally friendly, and needs less energy.
A simple system consists of solar photovoltaic (PV) panels, DC controller, DC water pump, and a very efficient DC converter. In this thesis, a triple DC-DC converter has been developed. The purpose for the triple output DC-DC converter is to provide the power needed to power up and control the DC water pump which requires different voltage levels.
A complete solar photovoltaic system with our proposed MPPT algorithm and developed DC-DC converter has been implemented. Detailed simulations and analysis are provided as well as prototyping phase is successfully achieved and tested. A 10W prototype was built and experimental results are provided for the proof of concept and to show the merits of the proposed thesis work.


title: Designing power aware wireless sensor networks leveraging software modeling techniques

contributor:
Liscano, Ramiro
Bradbury, Jeremy S.

subject:
Wireless sensor networks
UML modeling
Power consumption analysis
Model execution
Design patterns

abstract:
Wireless Sensor Networks (WSNs) are typically used to monitor specific phenomena and gather the data to a gateway node, where the data is further processed. WSNs nodes have limited power resources, which require developing power efficient systems. Additionally, reaching the nodes after a deployment to correct any design flaws is very challenging due the distributed nature of the nodes. The current development of WSNs occurs at the coding layer, which prevent the design from going through a typical software design process. Designing and analyzing the software modules of a WSN system at a higher abstraction layer than at the coding level will enable the designer of a WSN to fix any design errors and improve the system for power consumption at an early design stage, before the actual deployment of the network.
This thesis presents multiple Unified Modeling Language (UML) design patterns that enable the designer to capture the structure and the behavior of the design of a WSN at higher abstraction layers. The UML models are developed based on these design patterns that are capable of early validation of the functional requirements and the power consumption of the system hardware resources by leveraging animation and instrumentation of the UML diagrams.
To support the analysis of power consumption of the communication components of a WSN node, the Avrora network simulator was integrated with the UML design environment such that designer is able to analyze the power consumption analysis of the communication process at the UML layer. The UML and the Avrora simulation integration is achieved through developing a code generator that produces the necessary configuration for Avrora simulator and through parsing the simulator results. The methodology presented in this thesis is evaluated by demonstrating the power analysis of a typical collector system.


title: A  geophysical and biochemical investigation of buried remains in contrasting soil textures in southern Ontario

contributor:
Forbes, Shari L.
Carter, David O.

subject: Forensic science

abstract:
Ground penetrating radar (GPR) is a non-invasive, geophysical tool used for the
detection of clandestine graves. GPR operates by detecting density differences in soil by
the transmission of high frequency electromagnetic (EM) waves from an antenna. A 500
Megahertz (MHz) frequency antenna is typically used for forensic investigations, as it
provides a suitable compromise between depth of penetration and sub-surface
resolution. Domestic pig (Sus scrofa) carcasses were clothed in 100% cotton t-shirts and
50% cotton/50% polyester briefs, and buried at a consistent depth at three field sites of
contrasting soil texture (silty clay loam, fine sand and fine sandy loam) in southern
Ontario. GPR was used to detect and monitor the graves for a period of 14 months post
burial. Analysis of collected data revealed that GPR had applicability in the detection of
clandestine graves containing remains in silty clay loam and fine sandy loam soils, but
was not suitable for detection in fine sandy soil. Specifically, within a fine sandy loam
soil, there is the potential to estimate the post burial interval (PBI), as hyperbolic grave
response was well defined at the beginning of the 14 month burial duration, but
became less distinctive near the completion of the study.
Following the detection of a clandestine grave containing a carcass, collection of
gravesoil, tissue and textile samples is important for the estimation of the stage of
decomposition and the post burial interval (PBI) of the remains. Throughout the
decomposition process of a carcass, adipose tissue is subjected to hydrolytic enzymes
that convert triglycerides to their corresponding unsaturated, saturated and salts of
fatty acids. The composition of fatty acids in the decomposed tissue will vary with the
post mortem period, but it is unknown what affect the soil texture has on lipid
degradation. As decomposition proceeds, fatty acids can leach from the tissues into the
surrounding burial environment. Fatty acid analysis of gravesoil, tissue and textile
samples, exhumed at two, eleven and fourteen month post burial intervals, was
conducted using diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS),
attenuated total reflectance – Fourier transform infrared (ATR-FTIR) spectroscopy and
gas chromatography – mass spectrometry (GC-MS). Infrared (IR) spectroscopy analysis
of the samples provided a qualitative profile of lipid degradation. Analysis of gravesoil
samples did not reveal IR spectroscopy bands attributable to fatty acid degradation or
adipocere formation. IR spectroscopy analysis of tissue samples is applicable for the
estimation of carcass decomposition in all of the soil textures tested. Results of textile IR
spectroscopy analysis revealed limited potential to estimate the stage of carcass
decomposition in silty clay loam soil. GC-MS was used to quantify the peak area ratio
(area/int std area) (PAR) of myristic (C14:0), palmitic (C16:0), palmitoleic (C16:1), stearic
(C18:0) and oleic (C18:1) acids. GC-MS results revealed that analysis of both tissue and
textile samples can be useful in the estimation of the stage of decomposition and the
PBI of carcasses in all three of the soil textures tested.
The results of this research may have applicability within forensic investigations
involving decomposing bodies by aiding in the location of clandestine graves in silty clay
loam and fine sandy loam soil through the use of GPR. Infrared spectroscopy and GC-MS
analysis of the fatty acid composition of tissue and textile samples may also be
incorporated into investigational protocols to aid in the estimation of the stage of
decomposition and the PBI of a body.


title: Recidivism and treatment attrition among persons who sexually offend (PSOs): applying the integrated risk assessment and treatment system (IRATS)

subject:
Sexual offending
Risk assessment
Treatment
Persons who sexually offend

abstract: The aim of this thesis was to investigate whether the Integrated Risk Assessment and Treatment System (IRATS; Looman & Abracen, 2013) can provide an explanatory framework for understanding persons who sexually offend (PSOs). The IRATS is comprised of several overarching components: Deviant Sexual Arousal, Psychological Vulnerability, and Criminality. Study 1 investigated whether the IRATS components predict the likelihood that an incarcerated sample of PSOs will engage in sexual recidivism. This sample consisted of convicted PSOs who were assessed at the Regional Treatment Centre High Intensity Sex Offender Treatment Program (RTCSOTP), provided by the Correctional Service of Canada (CSC). Study 2 investigated whether the IRATS components predict the likelihood that a community sample of PSOs will terminate their treatment prematurely. This sample consisted of PSOs who were assessed at the Sexual Behaviours Clinic (SBC) at the Centre for Addiction and Mental Health (CAMH). The results of both studies indicated that the three components, together, significantly predict the outcomes of interest, and the Criminality component appears to drive this relationship. Implications of these findings are discussed herein.


title: Retrospective assessment of human exposures to low dose ionizing radiation using Electron Paramagnetic Resonance (EPR) dosimetry with tooth enamel

subject:
X-band CW EPR spectroscopy
EPR dosimetry with tooth enamel
Ionizing radiation
Free radicals
Low doses

abstract: This study collected the extracted teeth from people of different ages in the Durham region and analyzed them using the X-band CW EPR spectroscopy. The total dose rate from the natural and anthropogenic sources was 1.9721 mSv/year. The anthropogenic dose rate from the various sources was 0.6341 mSv/year, about 47.39% of the natural background dose (1.338 mSv/year) in Durham Region, Ontario. The combined anthropogenic doses from these sources were lower than the local background dose in Durham Region, Ontario, and lower than the regulatory annual effective dose limit of 1 mSv/year in Canada. These data demonstrated that the background doses to the public are lower than the regulatory limit. There is a minimal risk to the public from the anthropogenic doses in Durham Region populations. The dose contribution of the nuclear generating stations is small in Durham Region, Ontario. So, the excess anthropogenic doses could be from diagnostic radiology, nuclear medicines, radiation therapy, and other industrial uses of radiation or radioactive materials, but further study would be needed for conclusions about this region's situation. At the same time, there are more chances of providing deciduous teeth for the low dose (10 - 100 mGy) reconstruction in the actual radiation accidents or chronic exposures. To this end, this study used the dose spiking technique in alanine, where a low dose down to 20 mGy was measured with reasonable precision and accuracy. The same method was used in deciduous teeth for measuring low doses, which was challenging to measure precisely using the conventional EPR methods. The measurement accuracy and reproducibility in the deciduous teeth enamel were significantly higher in that dose range than the conventional methods. Thus, this method can solve the measurement problems associated with low doses and is helpful for retrospective and accident dosimetry. Finally, this study concluded that the total anthropogenic doses in the teeth of Durham Region residents were lower than the regulatory limits. The dose spiking technique can be used to measure low doses in tooth enamel for retrospective and accident dosimetry.


title: Molecular characterization of the interactions of the Resistance-Nodulation-Division Pump MexJK of Pseudomonas aeruginosa with outer membrane proteins OprM and OpmH.

subject:
Multidrug resistance
Resistance nodulation division
Efflux
Gram-Negative
Chimera

abstract: Pseudomonas aeruginosa is an important Gram-negative opportunistic pathogen, which has become a significant threat due to wide-spread antimicrobial resistance. Resistance Nodulation Division efflux pumps are important contributers to antimicrobial resistance in P. aeruginosa and other organisms. Resistance nodulation division efflux pumps are composed of three proteins; however, the mechanism by which the three proteins interact to form a functional complex remains, for the most part, unknown. The goal of this project is to further our understanding of how these proteins interact, to better understand how these efflux pumps operate in hopes of identifying novel therapeutic targets. We constructed a single copy expression system to study MexJK in the presence of either OprM or OpmH and confirmed these constructs using qRT, immunoblot and MIC. Chimeric OprM proteins were constructed by swapping α-helical domains from the OpmH protein. Using these chimeric proteins, we were able to identify regions within OprM/OpmH that may be responsible for substrate specificity by generating chimeric proteins. Taken together this data broadens our understanding of how this complex interacts.


title: Analysis, assessment and optimization of biomass mixed heavy-oil driven integrated gasification combined cycle for multigeneration

subject: Energy Exergy Multigeneration IGCC Gasification

abstract:
There has been increasing interest in employing Integrated Gasification Combined Cycles (IGCC) using various biomasses and low-rank coals for producing multiple outputs. The most of the existing IGCC plants do not conserve the low-grade heat, use air separation
unit and the presence of coal produces high amount of carbon based emissions. The production of syngas through gasification of renewable feedstocks, such as biomass, organic food waste and animal manure is an attractive option with less emissions. In this thesis, three novel multigeneration IGCC based on organic and refinery wastes are
specifically developed for three sectors; community, food industry and refinery. The systems are simulated using Aspen (Plus) and results are validated through energy and exergy analyses, and research reported in the literature.
The exergy analysis is performed with the help of Engineering Equation Solver (EES). The developed systems can be employed anywhere in the world with some modifications, however, the case studies are performed for Saudi Arabia for assessment. The Genetic Algorithm model is used to optimize the developed systems. A multi-objective optimization approach is applied to achieve the best performances of the developed systems. Three objectives function used in this study include; exergy efficiency, total cost and CO2 emissions. The developed systems are environmentally benign as the production of CO2 is low enough to meet the stringent environmental regulations.
The energy and exergy efficiencies of the cold gas, overall, gas turbine and steam turbine for the proposed systems 1 are found to be 58.2% and 57.6%, 55.9% and 32.1%, 29.8% and 26.7%, 34.1% and 60.1%, respectively. The energy and exergy efficiencies of the cold gas, overall, gas turbine and steam turbine for the proposed systems 2 are found to be 62.1% and 61.4%, 57.9% and 33.3%, 29.2% and 25.9%, 33.7% and 61.7%, respectively. The energy and exergy efficiencies of the cold gas, overall, gas turbine and steam turbine for the proposed systems 3 are found to be 68.3% and 68.7%, 60.7% and 34.8%, 27.8% and 24.7%, 34.4% and 60.3%, respectively. The highest magnitude of
exergy destruction occurs in combustion chamber. The electrical power output for system 1, system 2, and system 3 is found to be in the order of 461 MW, 433 MW and 466 MW, respectively.


title: Firefighter resilience assessment using a structured approach

subject:
Occupational stress
Firefighters
Heart rate variability
Public safety personnel
Resilience

abstract: This thesis proposes a resilience assessment model to assess the physiological changes experienced during a simulated firefighting environment. Currently, a resilience assessment model that measures the response to job stressors does not exist. The model provides a mechanism to measure the level of progress or decline experienced by public safety personnel, while exposed to job-related stressors. The research design for the model includes analysis of heart rate and electrocardiogram-based RR intervals at baseline and during the training activity. The model was applied to a case study that involved an extreme heat (50° C) search and rescue training task for pre-service firefighters (mean age of 21 years and a standard deviation of 4.6 years with 20% female). The performance of the female participants revealed a 54% higher standard deviation of normal R-R interval (SDNN) score compared to male participants. Furthermore, the average of the mean heart rate (HR) for males was 18% higher than the females. The SDNN for 93% (39) of males was less than 100ms as compared to the female SDNN where only 22% (2) of participants fell below 100 ms. Applying the model revealed female participants to be more resilient than their male counterparts. Prior studies have not addressed biological sex differences in their studies and this needs to be further explored. Implementation of the resilience assessment model to assess and improve the effectiveness of resilience training programs could benefit firefighters by reducing the incidence of PTSD, depression and workplace injuries.

abstract: University of Ontario Institute of Technology


title: Effects of endosulfan on human MCF-7 breast cancer cells

subject:
Endosulfan
Cell signaling
RANKL
Breast cancer
Proliferation

abstract: Organochlorine pesticides (OCs) are environmental toxicants with important links to human health. They have been found to activate signalling pathways within cells and thereby affect cell survival and proliferation. Receptor Activator of Nuclear Factor kB (RANK) ligand and its receptor RANK are crucial for mammary epithelial proliferation in pregnancy and have recently been linked to hormone induced breast cancers. The objectives of this study were to confirm the proliferative effects of an OC (endosulfan) on human MCF-7 breast cancer cells, identify activated intracellular signaling pathways and investigate changes in RANK and RANKL gene expression. This study showed that endosulfan has a stimulatory effect on human MCF-7 cell proliferation, which may be invoked through activated intracellular signaling pathways (JNK, ERK1/2 and p38). In addition, there was a down regulation of RANK and upregulation of RANKL gene expression suggesting endosulfan is capable of modulating both cellular behavior and gene expression.


title: Development and assessment of renewable ammonia and methanol production systems

subject:
Ammonia
Methanol
Thermal management
Renewable energy
Cooling

abstract: In this thesis, four renewable energy-based integrated systems for sustainable communities are developed. System 1 consists of a single-stage OTEC plant integrated with an ammonia production and district cooling system. Two different operation cases of the analyzed system are considered, where for the first case 50% of the power produced is used to produce ammonia as an energy storage medium. The second case considers the power production system integrated with district cooling system. The highest energy and exergy efficiencies are found to be 1.37% and 56.17% for case 1, respectively. As for the case 2 the maximum energy and exergy efficiency of the OTEC plant is found to be 1.83% and 78.02% respectively. System 2 consists of wind turbines and solar PV units for power production. The plant integrates a power production system with a district cooling and ammonia synthesis system. The system provides 40% of the system produced to the ammonia synthesis system. Ammonia is used as an energy storage medium. The maximum energy and exergy efficiencies of the system are found to be 21.2% and 21.3%. System 3 is a trigeneration system, that consists of a two-stage Rankine cycle that integrated with an electrolytic cation exchange membrane (ECEM) reactor for carbon dioxide and hydrogen production to feed the methanol production system. The system performance is analysed under three different cases: case 1: ECEM reactor operates at its current efficiency with fuel production and district cooling being the only products, case 2: ECEM reactor operates at proton exchange membrane (PEM) efficiency, and case 3: Only power is produced with no fuel. The maximum overall energy efficiencies of the cycle are found to be 8.0, 8.6, and 7.3% for cases 1, 2, and 3, respectively. Finally, system 4 takes into consideration a novel integration of a thermal management system integrated within a bifacial PV module. The bifacial modules are assessed for offshore use. The modules are able to boil ammonia at a pressure of 8.97 bar under a temperature of -5oC and a peak solar irradiance of 620 W/m2.


title: Bifurcation analysis of a nonlocal two-communication mechanism model for animal aggregation with O(2)-symmetry

subject:
O(2)-symmetry
Nonlocal hyperbolic model
Two-communication mechanism model

abstract:
The study of animal aggregations has become a topic of great interest due to its practical
applications and theoretical significance. The common occurrence of these aggregations in
nature lead to a large variety of models that have been proposed and investigated over the
years. In this thesis, we present a class of models that considers communication among
the individuals to be the basis of the social interaction within a group. In particular, we
present the nonlocal hyperbolic model with two-communication mechanisms in a domain
with periodic boundary conditions introduced by Eftimie (J. Theoretical Biol., 337, 42-53,
2013). We show that the system is symmetric with respect to the group O(2) of spatial
translations and reflection. Using symmetry techniques from the text by Golubitsky et
al. (Singularities and Groups in Bifurcation Theory, Vol II. Springer, 1988), we focus
on studying a spatially homogeneous equilibrium and its linear stability as a function of
parameters for attraction and repulsion. Given this symmetry perspective, we obtain a
decomposition of the linearization at the equilibrium in terms of 4 x 4 matrices. We obtain
a diagram in the attraction and repulsion parameter space for which the critical curves
forming the boundary of the asymptotic stability region for the equilibrium are shown.
Given the obtained boundaries, we then describe the patterns obtained via steady-state
and Hopf bifurcations with symmetry as critical curves are crossed.


title: Micro-differential evolution: diversity enhancement and comparative study.

contributor:
Rahnamayan, Shahryar
Tizhoosh, Hamid R.

subject:
Diversity
Evolutionary algorithms
Micro-differential evolution
Comparative study

abstract:
Evolutionary algorithms (EAs), such as the differential evolution (DE) algorithm, suffer
from high computational time due to large population size and nature of evaluation, to
mention two major reasons. The micro-EAs employ a very small population size, which
can converge to a reasonable solution quicker; while they are vulnerable to premature
convergence as well as high risk of stagnation. One approach to overcome the stagnation
problem is increasing the diversity of the population. In this thesis, a micro-differential
evolution algorithm with vectorized random mutation factor (MDEVM) is proposed, which
utilizes the small size population benefit while preventing stagnation through diversification
of the population. The following contributions are conducted related to the micro-DE
(MDE) algorithms in this thesis: providing Monte-Carlo-based simulations for the proposed
vectorized random mutation factor (VRMF) method; proposing mutation schemes
for DE algorithm with populations sizes less than four; comprehensive comparative simulations
and analysis on performance of the MDE algorithms over variant mutation schemes,
population sizes, problem types (i.e. uni-modal, multi-modal, and composite), problem
dimensionalities, mutation factor ranges, and population diversity analysis in stagnation
and trapping in local optimum schemes. The comparative studies are conducted on the
28 benchmark functions provided at the IEEE congress on evolutionary computation 2013
(CEC-2013) and comprehensive analyses are provided. Experimental results demonstrate
high performance and convergence speed of the proposed MDEVM algorithm over variant
types of functions.


title: Genetic analysis of cellulose crystallization in Gluconacetobacter xylinus

subject:
Gluconacetobacter xylinus
Bacterial cellulose
Cellulose synthase
Pellicin
Site-directed mutagenesis

abstract: In nature, polysaccharides, such as cellulose, are important biopolymers involved in numerous biological functions including prevention of cellular desiccation, energy storage, osmoregulation, and cell wall formation. Apart from having a relevant biological role, cellulose also has a great economic importance. For instance, cellulose provides the raw material for paper and textile production, and it is predicted to become a key precursor for glucose-derived ethanol. The mechanisms underlying cellulose biosynthesis are not completely understood. Elucidation of these mechanisms are essential for efficient cellulose production and industrial applications. In an effort to gain a better understanding of the cellulose biosynthesis process and its regulation, the crystallization of cellulose was investigated in Gluconacetobacter xylinus mutants resistant to a novel inhibitor of cellulose I formation known as pellicin. Through the use of forward genetics and site-directed mutagenesis, the mutations A449T and A449V in the G. xylinus BcsA protein were found to be important to confer high levels of pellicin resistance. Phenotypic analysis of the BcsA A449T and BcsA A449V mutants did not reveal other apparent phenotypic alterations when compared to the wild type. This suggests that these mutations are exclusively involved in cellulose crystallization. The localization of the A449 amino acid residue in the BcsA protein and structural analysis of both the native and the mutant BcsA proteins, by means of 3D modelling, suggest that pellicin may inhibit cellulose crystallization either by affecting the translocation process of the glucan within the BcsA protein or by allosterically altering protein-protein interactions.


title: Analysing atomic structure in nano-scale imagery

contributor:
Qureshi, Faisal Z.
Tamblyn, Isaac

subject: Computer-vision Nanoscale Atom Image-processing Image

abstract:
This thesis presents methods for both detecting atoms and reconstructing single layer molecular
geometry depicted within high resolution nanoscale imagery. Nanoscale imaging is a common
method of analysing molecular structures produced through self-assembly. The second derivatives
of the nanoscale images are then computed and used to aid in analysis of the depicted
molecules. Peaks from the derivative images are used as the locations of the atoms and using
those locations we derive the molecular geometry. In order to efficiently determine the performance
of our proposed methods, a system to synthesize HRTEM imagery and ground truth
data was developed. We demonstrate and compare the effectiveness of our system to other
proposed systems using both experimentally produced nanoscale images and the synthetic data
that has been produced.


title: Do extroverts create stronger passwords?

subject: Passwords Personality Personalities Password Authentication

abstract:
We investigate the relationship between personality types and the strength of created and
selected passwords. For this purpose, we conducted an experiment on Amazon’s Mechanical
Turk, with 510 participants. Participants were given a pre-questionnaire that included,
among others, three binary questions: “Password Awareness”, “Security Training” and
“Account Hijacking”, which were used to predict participants’ exposure to passwords in
the past. Our results suggest that participants with higher levels of Extroversion, tend to
create stronger passwords, if they were not required to change an online account password
in the past (e.g., due to a security incident). In contrast, participants with lower levels of
Extroversion tend to create stronger passwords (though not significantly), if they had been
required to change an online account password in the past. These results indicate that there
is a distinct relationship between the Extroversion personality dimension and the way we
create passwords, whether it be in a familiar situation or not. Though password strength, as
investigated, is the criterion of the aforementioned tests, it is worth mentioning that Extroversion
cannot be deemed a predictor in this domain. We also investigated the relationship
between personality and several password characteristics such as the total length, letters,
digits, and symbols used within a password. To this end, we note that for participants who
have had to change an online account password for the first time, Extroversion was directly
correlated with creating and selecting shorter passwords, Openness was directly correlated
with creating passwords containing fewer letters, but more numbers and symbols, and Conscientiousness was directly correlated with creating passwords containing fewer symbols.
These results conclude that there is a distinct correlation between the construction of passwords
and personality when participants are required to change an online account password
for the first time. This thesis presents the detailed observations and findings from our experiment,
discuss potential considerations for contradictions, and identify related future
research.


title: The influence of general cognitive training on sport-specific performance in wheelchair basketball

subject:
Perceptual-cognitive training
General-cognitive training
Paralympics
Athlete development
Sport expertise

abstract: There has been tremendous growth of sport-science literature completed on able-bodied or mainstream athletes. However, research completed on the development of perceptual-cognitive skills on athletes with physical disabilities is scarce. Twelve Senior high performance/National Academy athletes were recruited from Wheelchair Basketball Canada to participate in a pre-test vs. post-test intervention study of general cognitive training (GCT) effects on sport-specific performance. Athletes were tested in general executive functioning, sport-specific cognitive skills (pattern recall), and sport-specific physical performance indicators. The intervention was 4-weeks of multiple object tracking (MOT). Results from statistical analysis show little-to-no changes over the study period, which supports the hypothesis that participation in MOT would have no effect on performance in wheelchair basketball. Future research is needed in this area and would benefit from a larger sample size, a control-group, and extended study period. Coaches are encouraged to be cautious in their use of GCT programs in high performance athlete training environments.


title: Comparative assessment of small modular reactor Passive Safety System design via integration of dynamic methods of analyses

subject:
iPWR
PSS
Evaluation metrics
Scaling analysis
Dynamic PRA

abstract: Integral Pressurized Water Reactor (iPWR) type SMR designs were studied featuring Passive Safety Systems (PSS) in all cases. As many as 11 current SMR designs use PSS to remove decay heat. Variations in PSS designs were studied and compared using evaluation metrics and a proposed weighting method. This resulted in classification of iPWRs designs based on the methodology presented. A prototypic Passive Residual Heat Removal System (PRHRS) was then studied using a scaling analysis to compare the scaling ratio of system parameters, and failure probability relative to existing reference LWR plant data. The impact of single versus two-phase PRHRS designs was also considered. We found that a classical Probabilistic Risk Assessment (PRA) model describing active systems does not consider time evolution nor event ordering that a dynamic PRA approach can accommodate. We thus developed and realized basic coupling between LabVIEW as simulation code and CAFTA as PRA code. Coupling these codes using Python provides real-time simulation that leads to a dynamic simulation result. A representative difference in failure probability using dynamic versus classic PRA revealed that for one, there can be more component demands with different event ordering; thus providing insights into PSS failure probability in the iPWR-type SMR designs. The limitation of the work is essentially in the proprietary details of each SMR design. The value however is in the integrated method of system analysis.


title: Design and development of hydrophobic and protective polymer-based spray coatings for treating glass surfaces in building and automotive applications

subject:
Spray coating
Polymer blends
Transmittance
Water contact angle
Dynamic droplet behavior

abstract: Glass surfaces in buildings and vehicles are susceptible to two common problems: unrestricted energy transmittance of light-waves resulting in increased HVAC costs, and reduced visibility as a consequence of wetting during precipitation; which is an accident hazard for automobiles. In this context, the surface properties of the glass can be altered and enhanced by deliberately applying hydrophobic and/or protective topical coatings. This research focuses on evaluating the performances of multiple newly-formulated low-cost spray coatings based on polymethylmethacrylate (PMMA) and its blends with various polymers. The experimental comparative characterization study included: transmittance measurement, microstructure visualization, and wettability quantification under static and dynamic conditions. The obtained results indicated that PMMA enhanced the transparency and adhesion to the glass, whereas the addition of secondary polymers reduced wetting and increased blockage of ultraviolet and infrared light-waves. The developed coatings proved their implementation potential for applications where thermal radiation shielding and water repellency are required.


title: Exploring the use of flipped classrooms in secondary school chemistry classes

subject:
Flipped classroom
Chemistry
Secondary school
Videos

abstract: Previous research has suggested that the flipped classroom is effective for higher education students, however, limited research has been conducted for secondary school students. The purpose of this study was to investigate attitudes, benefits, challenges and learning performance of secondary students studying grade 11 chemistry. Fifty grade 11 chemistry students (21 male, 29 female) between 16 - 17 years old participated in this study. The data collection tools used included Likert survey questions, open-ended questions, pre- and post-tests, and focus group data. Attitudes, benefits and challenges regarding the flipped classroom were clustered into five themes: the learning environment in the classroom after watching the videos at home, understanding concepts presented, availability of resources, the effectiveness of learning strategies used, and the quality of videos. Overall, the attitude and benefits data indicated that most students were positive about the learning environment, thought they understood the concepts addressed, agreed that resources were readily available and rated the learning strategies highly. Students also had positive attitudes towards the videos used, enjoying the ability to control the pace and review the videos when desired. Some students expressed challenges with the learning environment, including the teaching methods used, the fast pace and environment, difficulty understanding the material and wanting more the lessons to be more effective and engaging. Student learning on knowledge and application questions increased significantly using the flipped classroom approach. The results of this study suggest that the flipped classroom approach to teaching is more complex than expected and educators must be flexible in their teaching practice to meet the needs of their students.


title: Thermodynamic performance assessment of three biomass-based hydrogen production systems

contributor:
Dincer, Ibrahim
Rosen, Marc

subject:
Biomass
Gasification
Hydrogen
Thermodynamics
Energy
Exergy
Hydrogen price

abstract:
Hydrogen is likely to be an important energy carrier in the future. It can be produced by the steam reforming of natural gas, coal gasification and water electrolysis among other processes. However current processes are not sustainable because they use fossil fuels or electricity from non-renewable resources. In this context, this thesis focuses on biomass based-hydrogen production and considers three plants intended for sustainable producing hydrogen using. These three systems are analyzed thermodynamically using Aspen Plus and their performances are examined and compared in regards to hydrogen yield. Therefore, comparisons of the systems are made based on several factors, including energy and exergy efficiencies. In addition, an economic analysis is performed in order to determine the minimum hydrogen production cost for these three systems. The results are expected to be useful to efforts for the design, optimization and modification of hydrogen production and other related processes. In the three system considered, the gasifiers are modelled using the Gibbs free energy minimization approach and chemical equilibrium considerations. Gasification, which is characterized by partial oxidation, is a vital component of several clean energy technologies including the ones considered here. Parametric analyses are carried out of several factors influencing the thermodynamic efficiency of biomass gasification.
The energy efficiencies were found to be between 22-33% for all systems. However the exergy efficiencies range from around 22 to 25%. It was also found that gasifier produces the greatest quantity of entropy, due to its high irreversibility, and merits attention from those seeking to improve efficiencies. It was found that the hydrogen production cost range varies between 1.28 and 1.84 $/kg for the three systems; this is higher than the cost for that produced from conventional oil.


title: “Feeling like Rapunzel, you know?”: A narrative inquiry of youth, boredom, and deviance

subject:
Youth
Boredom
Deviance
Narrative inquiry
Late modernity

abstract: In a late modern society, the presence of placelessness and meaninglessness can be overwhelming to individuals, especially youth. Jock Young’s theory of human behavior suggests that individuals engage in crime to rid themselves of boredom. Understanding the role that boredom plays in criminal offending is important, as it can help uncover how youth choose to spend their time and who they spend their time with. By using a narrative storytelling approach of inquiry, this thesis focuses on the lived experiences of youth collected by virtual interviews with 16 university students. An emphasis for this research is placed on how youth recall, examine, and reflect on their lived experiences with boredom, leisure time, and their environment. Findings from this research suggest that boredom is common among youth and can lead to various behavioural outcomes.


title: Energy and exergy analyses of biomass cogeneration systems

subject:
Biomass
Efficiency
Combine cycles
Energy and exergy

abstract:
Biomass cogeneration systems can generate power and process heat simultaneously from
a single energy resource efficiently. In this thesis, three biomass cogeneration systems are
examined. Parametric analysis of back pressure steam turbine cogeneration system,
condensing steam turbine cogeneration system and double back pressure steam turbine
cogeneration system is conducted. Energy and exergy analyses are performed for three
biomass based cogeneration configurations. The parametric analysis demonstrates the
effects of varying operating conditions (temperature: 340 oCto 520 oCand pressure: 21bar
to 81bar). A higher steam inlet temperature and pressure to the turbine yields better
energy and exergy efficiencies and performance. Steam inlet conditions to the turbines
and process heater requirements influence the power output and cogeneration system
efficiencies. Greenhouse gases reduction is achieved by cooperating cogeneration
systems with biomass to reduce CO2 emissions and global warming potential in the
power industrial sectors.


title: Development of a method for genetic optimization of aerodynamic devices

subject:
Genetic algorithm
Shape optimization
CFD
OpenFOAM
Ahmed body

abstract: Driving stability, fuel efficiency and soiling reduction are important for modern vehicles. This thesis has developed a novel method for genetic optimization of aerodynamic devices for road vehicle applications with the objective of minimizing drag and lift. The method involves the integration of genetic algorithms, B-spline shape optimization and computational fluid dynamic using OpenFOAM. The method can generate multiple devices in a single run. It allows the user to decide the objective functions and number of devices to be generated. The method was successfully applied to generate unique device geometries based on the Ahmed body by optimizing the top flap device and bottom diffuser, as well as the combination of the two devices. In addition, advanced vortex identification techniques were applied to the novel aerodynamic devices developed. The study provided physical insight into the drag and lift reduction as well as soiling mitigation mechanisms by the new devices.


title: Acute cardiopulmonary responses to different intensities of exercise in healthy older adults

subject:
Older adults
Cardiopulmonary responses
Sprint exercise
High intensity exercise
Interval exercise

abstract: The overall purpose of this thesis was to study the acute cardiopulmonary responses to different intensities of exercise in healthy older adults. Thirty healthy older males and females (69.6 ǂ 6.2 yrs.; males n = 15) underwent maximal exercise testing to determine maximal oxygen consumption (VO2MAX) and peak power output (PPO), and completed each of the following exercise protocols in a randomized crossover design: high intensity interval exercise (HI; 1 minute 90% PPO followed by 1 minute 10% PPO, x10), continuous moderate intensity exercise (MOD; 20 minutes at 50% PPO), and sprint intensity interval exercise (SPRT; 20 second “all-out” sprints followed by 2 minutes of 50W, x3). Oxygen consumption (VO2), ventilation (VE), tidal volume (Vt), respiratory rate (RR), heart rate (HR), tissue saturation index (TSI) of the vastus lateralis and rated perceived exertion (RPE) were monitored during exercise sessions. Heart rate recovery (HRREC) was assessed after each exercise session and heart rate variability (HRV) was compared using resting and post-exercise values. Overall, it was found that high fit individuals attained the greatest VO2 peak during MAX while low fit females attained a larger VO2 peak during SPRT compared to MAX. The rate of HRREC was greatest in high fit males. These findings have important implications for the individualization of exercise prescription, Future research will need to compare the three different types of exercise training to determine which protocol leads to larger adaptations in older adults.


title: User-centric analytics for expert crowds

subject:
User modeling
Experts detection
Opinion inference
Social filtering
User-based trend prediction

abstract: Pervasiveness and permissiveness of social media made content verification an integral part of any analysis involving online generated data. The most natural and convenient way to assess content trustworthiness and validity is to examine it from the perspective of a user that authored it. With more studies switching their strategies of data collection from event-oriented to user-focused, it is crucial to outline and address the challenges pertaining to this approach. We propose a user-centric analytics paradigm as one of the solutions to this problem. It is casted as a three-tier framework, consisting of detection of topical experts, extraction and interpolation of their opinions and utilization of the latter in social filtering. The first is concerned with automatic identification of user's topical attribution on Twitter: while the platform is so popular among professionals, it does not support an explicit mechanism for community membership. We present three models exploiting semantic signature of a group and examine their performance on a case study of Twitter investment community. Interpolation of missing opinions is intended to handle mass amounts of periods with no activity peculiar to user streams. We introduce a number of community-based models exploiting user's historical activity, content and opinions of his immediate network, and also verify their feasibility to serve as an initialization scheme in low-rank matrix approximation. We also analyze how predictability changes from user to user and build a model based on his characteristics to assess this value beforehand. Finally, we present a concept of social filtering - an approach with objective to exploit plethora of available historical data for prediction of social trends. In contrast to collaborative filtering, it does not solicit explicit recommendations from users and operates on raw data. It is designed to automatically select “expert” users - individuals whose content is the most reflective of a target central to the application - and transform their posts into predictive signals.

abstract: University of Ontario Institute of Technology


title: Modeling and analysis of metal cutting process using self-propelled rotary tools

contributor:
Kishawy, Hossam
Mohany, Atef

subject:
Machining
Difficult-to-cut materials
Rotary tools
Modeling
Optimization

abstract: Machining difficult-to-cut materials is still one of the challenges facing different industries such as aerospace, nuclear and automotive sectors. That’s mainly because of the excessive heat generated, which affects the tool wear behavior and machinability performance. Rotary tools can be employed to solve these issues as they offer an acceptable tool life compared to traditional tools, especially under dry-environment conditions. Despite the attempts offered in the area of machining with rotary tools, there is a noticeable lack in understanding the physical aspects and mechanics of this process. Thus, the current work focuses on three main pillars to fully address this research gap. The first pillar of this study presents a novel analytical model to predict the cutting forces and tool rotational speeds during the machining process using self-propelled rotary tools with considering the tool bearing friction. The prediction capabilities of this analytical model are higher than all existing models in the open literature. The objective of the second pillar is to propose a hybrid finite element model which is able to predict the temperature distribution during cutting with self-propelled rotary tools. The proposed model addresses the limitation of other previous models as it is purely focused on significant aspects such as; heat partition factor and the contact area between the tool and the chip. The simulation results in terms of cutting forces, temperature, heat flux, and the contact area between the chip and the tool are obtained, and good agreement is observed between the numerical and experimental results. In terms of the third pillar, deep-understanding of the process mechanisms is fully discussed through conducting experimental tests on AISI 4140 hardened-steel, followed by analysis of variance, empirical modeling of the process, and process optimization. Besides, a detailed mechanism for the machining process with self-propelled rotary tools is concluded. It should be stated that this work offers a valuable comprehensive analysis for the metal cutting industry in terms of modeling, optimization, and assessment of the machining process with rotary tools.