VictorJuiz/thesis huggingface dataset:
Propulsion System Development for the CanX-4 and CanX-5 Dual Nanosatellite Formation Flying Mission

The Canadian Nanosatellite Advanced Propulsion System is a liquefied cold-gas thruster system that provides propulsive capabilities to CanX-4/-5, the Canadian Advanced Nanospace eXperiment 4 and 5. With a launch date of early 2014, CanX-4/-5's primary mission objective is to demonstrate precise autonomous formation flight of nanosatellites in low Earth orbit. The high-level CanX-4/-5 mission and system architecture is described. The final design and assembly of the propulsion system is presented along with the lessons learned. A high-level test plan provides a roadmap of the testing required to qualify the propulsion system for flight. The setup and execution of these tests, as well as the analyses of the results found therein, are discussed in detail.

Keywords: aerospace
microsatellite
nanosatellite
propulsion
formation flying
canx4
canx5
canx-4
canx-5
canx-4/-5
SFL
UTIAS
cold-gas thruster
satellite
CNAPS
NANOPS
nano
sulfur hexafluoride
SF6
vibration testing
spacecraft environmental testing
propulsion testing
low earth orbit
canx2
canx-2
station keeping
orbit maneuver
orbital station-keeping
liquefied cold-gas propulsion
micropropulsion
engineering
space
canadian
space flight laboratory
canadian advanced nanospace experiment
PSLV
micro-propulsion
thruster
interferometry
ground moving target indicator
on-orbit servicing and inspection
Advisor: Zee, Robert
Development of a Free Lime Monitoring System for the Kraft Recovery Process using Zeta Potential

The presence of Ca(OH)2 (or free lime) in lime mud can cause many problems in the recovery process of kraft pulp mills. Conventional free lime analyses require extensive laboratory work and give inconsistent results. A systematic study was performed to determine if zeta potential, a quickly measurable dispersion characteristic, can be used to indicate the presence of free lime in the recovery process. Measurements were made on synthetic wet lime mud to simulate samples collected after the white liquor clarifier in pulp mills. The results show that zeta potential increases from negative to positive when the free lime content in the lime mud exceeds a critical threshold. This change from negative to positive zeta potential of the lime mud slurry can be used as a basis for developing an on-line monitoring system that effectively detects free lime in the lime mud in order to avoid problems associated with overliming in the recovery process.

Keywords: Zeta Potential
Liming Ratio
Free Lime
Kraft Recovery
Causticizing Plant
Green Liquor
White Liquor
Reburned Lime
Pulp and Paper
Advisor: Tran, Honghi
Evaluation of Test Methods for Determining the Water to Cement Ratio of Fresh and Hardened Concrete

The purpose of this research was to determine the accuracy of two test methods used in measuring the water to cement ratio (w/c) of fresh and hardened concrete. The microwave oven test based on a current ASTM Draft was used in determining the w/c of fresh concrete while the modified Norwegian PF-method was used to determine the w/c of hardened concrete. The microwave oven evaporates the water of a 1500 gram sample of fresh concrete to determine a w/c and can accurately measure the w/c within 0.05 of the true value. The modified PF-method uses an absorption method similar to ASTM C97 and Powers’ hydrations models to determine the w/c of hardened concrete. 100mm diameter concrete cores were prepared from slabs and 50mm thick concrete cylinders were tested. The results from this hardened concrete test had a large degree of variability; however, it was a useful indicator of concrete segregation.

Keywords: concrete
cement
Advisor: Hooton, Doug
Reliable Writeback for Client-side Flash Caches

Modern data centers are increasingly using shared storage solutions for ease of management. Data is cached on the client side on inexpensive and high-capacity flash devices, helping improve performance and reduce contention on the storage side. Currently, write-through caching is used because it ensures consistency and durability under client failures, but it offers poor performance for write-heavy workloads. In this work, we propose two write-back based caching policies, called write-back flush and write-back persist, that provide strong reliability guarantees, under two different client failure models. These policies rely on storage applications such as file systems and databases issuing write barriers to persist their data, because these barriers are the only reliable method for storing data durably on storage media. Our evaluation shows that these policies achieve performance close to write-back caching, while providing stronger guarantees than vanilla write-though caching.

Keywords: Client-side Caching
Flash Storage
Performance
Consistency
Durability
Advisor: Goel, Ashvin
Brown, Angela Demke
Automated Vitrification of Mammalian Embryos on a Digital Microfluidic Platform

This thesis presents the development of a digital microfluidic system to achieve automated sample preparation for the vitrification of mammalian embryos for clinical in vitro fertilization (IVF) applications. This platform included micro devices fabrication, an imaging system, a high voltage control system, and a LabVIEW interface. Individual micro droplets manipulated on the digital microfluidic device were used as micro-vessels to transport a single embryo through a complete vitrification procedure. The device showed cell survival and development rates of 77% and 90%, respectively, which are comparable to the control groups that were manually processed. Technical advantages of this approach, compared to manual operation and channel-based microfluidic vitrification, include automated operation, cryoprotectant concentration gradient generation, and feasibility of loading and retrieval of embryos.

Keywords: microfluidics
vitrification
Advisor: Sun, Yu
High Level Debugging Techniques for Modern Verification Flows

Early closure to functional correctness of the final chip has become a crucial success factor in the semiconductor industry. In this context, the tedious task of functional debugging poses a significant bottleneck in modern electronic design processes, where new problems related to debugging are constantly introduced and predominantly performed manually. This dissertation proposes methodologies that address two emerging debugging problems in modern design flows. First, it proposes a novel and automated triage framework for Register-Transfer-Level (RTL) debugging. The proposed framework employs clustering techniques to automate the grouping of a plethora of failures that occur during regression verification. Experiments demonstrate accuracy improvements of up to 40% compared to existing triage methodologies. Next, it introduces new techniques for Field Programmable Gate Array (FPGA) debugging that leverage reconfigurability to allow debugging to operate without iterative executions of computationally-intensive design re-synthesis tools. Experiments demonstrate productivity improvements of up to 30 x vs. conventional approaches.

Keywords: RTL Debugging
FPGA
Triage
Clustering
Advisor: Veneris, Andreas
Influence of Biogenic Silica from Terrestrial Vegetation on Riverine Systems and Diatom Evolution

Presently within the scientific literature no terrestrial biogenic silica models exist that compare by magnitude, processes transporting silica. Change in vegetation type has the potential to alter dissolved concentrations of Si in rivers and ultimately the oceans. Diatoms greatly depend on Si concentrations for growth, and as a result land cover change may have influenced onset diatom radiation during the Cenozoic. To expand our understanding of this cycle, a terrestrial biogenic silica model is proposed. This model accounts for biogenic silica production, dissolution and leaching through soils, as well as providing estimates for annual silica soil storage. A case study performed using the constructed biogenic silica model, showed an increase in oceanic DSi concentration during the Miocene (period of diatom diversification). However, this increase does not appear to have been sufficient to trigger global diatom radiation, suggesting multiple geographically isolated locations for this diversification.

Keywords: Biogenic Silica
Vegetation
Diatoms
Soils
Rivers
Leaching
Advisor: Cowling, Sharon
Modeling the Reaction Kinetics of the Enzymatic Hydrolysis of Lignocellulosic Biomass

Maximizing enzymatic hydrolysis performance can be achieved through the combination of experimental work and modeling. The present work utilizes an enzymatic hydrolysis model based on reaction kinetics, Langmuir adsorption isotherms, and product inhibition of enzymes (β-glucosidase, cellobiohydrolase, and endoglucanase). The model was developed from a 10% w/w corn stover system. Glucose yield sensitivity to changes in parameter values was assessed and linked to biomass and enzyme characteristics. A commercial enzyme cocktail (CEC) was subsequently characterized by FPLC and gel electrophoresis to identify key enzymes/activities, and the CEC was used in the enzymatic hydrolysis of 20% w/w steam-exploded hardwood. The model was applied to experimental data from the enzymatic hydrolysis of the steam-exploded hardwood, which provided characteristic reaction rate and inhibition parameters consistent with cellulose and xylan hydrolysis. These model-based analyses enhanced understanding of hydrolysis at commercially relevant solids loadings, while identifying pathways to improve enzyme cocktails and enhance biomass conversion.

Keywords: biofuel
enzymatic hydrolysis
reaction kinetics
modeling
bioconversion
reaction kinetics modeling
enzymatic hydrolysis optimization
Advisor: Saville, Bradley
Probing the Hydration of Ultrathin Antifouling Adlayers using Neutron Reflectometry

Adverse interaction and subsequent adsorption of biomolecular species (i.e. fouling) pose a great hindrance for medical and clinical applications (e.g. biosensors). Research into the mechanism behind antifouling coatings have shown a strong link between surface hydration and antifouling behaviour due to the existence of a ‘water barrier’ which prevents proteins from adsorbing onto the surface. In a previous study, a short, mono(ethylene-glycol) silane adlayer (MEG-OH) showed significantly different antifouling behaviour in comparison to its homolog – lacking the internal ether oxygen (OTS-OH). In the present work, neutron reflectometry (and modeling) was used to investigate the water density profiles at MEG-OH and OTS-OH silane adlayers on quartz and Si/SiO2 to determine whether the internal ether oxygen affects the adlayers’ interaction with water. Despite the limitations of studying such ultrathin organic films, the two systems showed different hydration profiles supporting the link between surface hydration and antifouling.

Keywords: Neutron Reflectometry
Antifouling
Biosensors
Hydration
Ultrathin film
Advisor: Thompson, Michael
Characterization of Nedd4 Function and its Interaction with Angiomotin

The HECT E3 ubiquitin ligase Nedd4-1 was previously shown to regulate diverse processes such as cell and animal growth, insulin signaling, and lysosomal trafficking. To further elucidate the cellular functions of Nedd4-1, Nedd4-1 knockout mouse embryonic fibroblasts were characterized relative to their wild type counterparts. Immunofluorescence experiments revealed an altered lysosomal distribution in the knockout cells, although their lysosomal proteolytic function appeared normal. Transmission Electron Microscopy revealed striking morphological differences, especially regarding the lysosome and endoplasmic reticulum of the knockout cells. Another aspect of my studies examined the interaction between Nedd4-1 and Angiomotin (p130-AMOT), which involves the same motifs required to sequester transcriptional co-activators YAP and TAZ in the cytoplasm. To test either a competitive or non-competitive mode of binding, co-immunoprecipitation experiments involving p130-AMOT, the Nedd4 proteins, and YAP or TAZ were performed, with results not supporting a competitive mode of interaction. Overall, my results demonstrate new Nedd4-1 cellular functions.

Keywords: Nedd4
Angiomotin
Ubiquitin ligase
biochemistry
Advisor: Rotin, Daniela
Extrinsic Substrate Stiffness Regulates Chondrocyte Phenotype through Actin Remodeling and MRTF Mechanotransduction Pathway

To obtain a cell source for cartilage tissue engineering primary cells are passaged on polystyrene dishes to increase cell number however, this stiff environment results in dedifferentiation. This study evaluates the role of microenvironment stiffness on regulation of passaged chondrocyte phenotype. Results show passaged cells on soft polyacrylamide gels (0.5kPa) become round, less proliferative, less contractile, have higher levels of globular actin (g-actin) compared to filamentous actin (f-actin), MRTF localization in the cytoplasm and down-regulation of MRTF associated genes such as type I collagen, alpha-smooth muscle actin, transgelin, tenascin C and vinculin. This suggests that the chondrogenic phenotype during passaging is regulated by actin polymerization and activation of MRTF signaling that induces expression of non-chondrogenic genes, and has functional effects as the cells become proliferative and contractile. Modulating substrate stiffness maybe a way to influence aspects of the chondrogenic phenotype in order to obtain sufficient cells suitable for cartilage tissue engineering.

Keywords: Tissue Engineering
Cartilage
MRTF
Actin
dedifferentiation
Advisor: Kandel, Rita
Engineering the Escherichia coli NikR Transcription Factor via Mutations in the α3 Helix

Escherichia coli NikR is a metal-responsive transcription factor that controls nickel uptake by regulating expression of a nickel-specific transporter, NikABCDE. NikR contains a high-affinity nickel-binding site, and nickel must occupy this site in order to activate DNA binding. Stoichiometric amounts of nickel bind to this site and stabilize the α3 helix and the preceding loop (residues 63 – 79). The α3 helix forms non-specific electrostatic interactions with the DNA. The current hypothesis is that nickel activates NikR-DNA binding by organizing α3 helix and activating non-specific DNA contacts, allowing NikR to scan along the DNA until it reaches the nik promoter. This presentation will examine this hypothesis by generating a nickel independent NikR through mutagenesis.

Advisor: Deborah, Zamble
The Effects of Serum from Obese Patients and Adipocyte-derived Cytokines on Growth of Prostate Cancer Cells In Vitro

Obesity has been related to a greater incidence of more aggressive, advanced stage prostate cancer. It is expected that serum adipokines related to obesity will promote a more aggressive phenotype in PC cells in vitro. Patient serum (n = 80) was obtained for analysis and divided into four patient groups based on obesity and prostate cancer status. Characteristics of serum-treated PC cells in vitro were measured. In a separate set of analyses, LNCaP and PC3 cells were treated with adiponectin and resistin in vitro, and cell characteristics were analyzed. Serum from obese PC patients induces greater amounts of cell migration and lower amounts of cell proliferation and invasion in vitro. Exogenous treatment of adiponectin on PC cells in vitro does not affect cell migration or invasion. However, adiponectin modulates cytosolic protein levels of soluble β-catenin and GSK-3β, indicating that its mechanism of action may be through the Wnt signalling pathway.

Keywords: oncology
urology
cancer
prostate
obesity
adipokines
prostate cancer
cytokines
adipocytes
adiponectin
resistin
fat cells
tumor
malignancy
neoplasm
body mass index
in vitro
wnt
proliferation
migration
invasion
LNCaP
PC3
overweight
fat
adiposity
beta-catenin
glycogen synthase kinase-3beta
Advisor: Venkateswaran, Vasundara
Klotz, Laurence
Determining Tree Water Acquisition with Stable Isotope Analysis in a Temperate Agroforestry System

The water acquisition strategies of trees in agroforestry systems may affect adjacent crops through competition for resources. This study characterizes the water uptake zones of Juglans nigra (walnut) and Populus sp. (hybrid of Populus deltoids X Populus nigra clone DN-177) (poplar) in a temperate agroforestry system. Isotopic analysis (δ18O) of soil water and tree xylem water occurred in early season and late season samples from the Agroforestry Research Station in Guelph, Ontario, Canada. Direct inference and multiple source mass-balance approaches showed that poplar exhibited a primary soil water uptake zone at 20 cm in early season, while walnut uptake was higher in the soil profile at 10 cm. Late season water uptake zones shifted to lower in the soil profile (40-70 cm) for both poplar and walnut trees. This study indicates: i) species dependent water acquisition zones, and ii) a shift to lower in the soil profile later in the growing season.

Keywords: agroforestry
water
Advisor: Isaac, Marney
Cation Impact on N-Nitrosodimethylamine (NDMA) Formation from Ranitidine in Different Water Matrices

In previous research, ranitidine has formed high yields of the disinfection by-product N-Nitrosodimethylamine (NDMA) upon chloramination. In the current research, bench-scale experiments were conducted to investigate the impact of cations (i.e., Ca2+, Mg2+, and Na+) on NDMA formation from ranitidine in three water matrices (Milli-Q® water, Lake Ontario water, and Otonabee River water) under practical chloramine disinfection conditions. In Milli-Q® water, excess cations did not change the yields of NDMA. NDMA formation kinetic profiles monitored in the lake and river water also indicated that elevating the cation concentrations did not affect the ultimate NDMA formation from ranitidine, but then did affect the observed rates of NDMA formation; the rates underwent an initial decrease and a subsequent increase as the cation concentrations were increased. The lowest reaction rates were observed in the lake and river water samples when they have a hardness level of 240 and 203 mg/L as CaCO3, respectively.

Keywords: Cations
NDMA
Ranitidine
Advisor: Andrews, Susan
Ultrafiltration Fouling: Impact of Backwash Frequency and Air Sparging

A bench-scale study was performed to optimize backwash frequency and air sparging conditions during ultrafiltration (UF) of natural surface waters in order to maximize water production and minimize irreversible fouling as well as operating and maintenance costs. Surface shear stress representing different air sparging conditions (continuous coarse bubble, discontinuous coarse bubble, and large pulse bubble sparging) was applied in combination with various backwash frequencies (0.5, 2 and 6 h) and fouling was assessed. Results indicated that air sparging with discontinuous coarse bubbles or large pulse bubbles significantly reduced the irreversible fouling rate while providing cost savings when compared to the baseline condition, which assumed a 0.5 h-backwash frequency and no air sparging during filtration. Cost savings were more pronounced at lower backwash frequencies, due to value associated with extra water produced over longer filtration times and longer membrane life resulted from fewer recovery chemical cleans because of lower irreversible fouling.

Keywords: ultrafiltration
fouling
air sparging
backwash
Advisor: Andrews, Robert C.
Study of Flexible Multi-wall Carbon Nano-tubes / Conductivepolymer Composites for Supercapacitor Applications

Conductive polymers are promising pseudo capacitive materials as they feature both good conductivity and high capacitance. Formation of composite between conductive polymers and carbon nanotubes is a proven technique in enhancing the material electroactivity. In-situ polymerization of conductive polymers includes polyaniline, polypyrrole and PEDOT: PSS and composite with MWCNT has been successfully achieved. Composites fabricated by using different dopants and their performance were studied. Excellent achieved capacitive performance is due to the combination of pseudo capacitance and double layer capacitance. The MWCNTs content has significant influence on the morphology and structure of the polymerized ECP in the composite. And therefore affects the material conductivity and the charge storage performance. Two electrodes cell performance shows that Ppy/MWCNT composite shows a more promising performance as electrode materials for EC applications in contrast to PANI/MWCNT and PEDOT: PSS/MWCNT composites.

Keywords: Supercapacitors
Conductive polymer
Carbon nanotubes
composites
Polypyrrole
Polyaniline
PEDOT
Advisor: Naguib, Hani
Lian, Keryn
Local to Mobile Devices for Nuclear Operations

The AECL National Research Universal (NRU) reactor has implemented a new mobile device to help Operators collect instrument data. Instruments display readings through various analog and digital devices. Before the change, Operators collected readings via a paper and pen method. With the implementation of the mobile device, Operators scan a barcode and input the instrument’s reading using a mobile device. To understand the factors that influence Operator acceptance of the new technology, the Technology Acceptance Model (TAM) was used to identify determinants that have the biggest impact on the Operators’ intention to use the mobile device. The TAM results identified the determinants that were most influential and the mobile interface was redesigned, based on the TAM results. Once the interfaces were redesigned they were evaluated through a usability study that compared the original interface with the newly designed screens. The results did not show statistically significant differences between the screens.

Keywords: mobile devices
TAM
Advisor: Jamieson, Greg
Toward More Efficient Annealing-based Placement for Heterogeneous FPGAs

imulated Annealing (SA) is a popular placement heuristic used in many commercial and academic FPGA CAD tools. However, SA placement requires high runtime to produce good quality results. As FPGAs continue to grow in size, runtime has become more crucial for SA-based placers. This thesis aims to improve SA placement by making it more efficient in two key areas for large heterogeneous FPGAs: move generation and placement cost evaluation. This work shows that by using Median Region moves for heterogeneous architectures, the wirelength is reduced by 5% while maintaining the same critical path delay. We also show that by using a better search data structure the runtime is improved by 5%. A new Timing Cost function incorporating Delay Budgets is introduced in this work, and it improves the circuit speed by 4% with no degradation in wirelength. This cost function also performs better on large circuits, where it improves circuit speed by 7%.

Advisor: Betz, Vaughn