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Evaluating 238U external background for SNO+ experiment using radon Aasays and 214Bi analysis
Get PDFSNO+ is large multipurpose detector located at SNOLAB filled with liquid scintillator.
The scintillator will then be loaded with Te isotope, allowing to look for neutrino-less double
beta decay which is extremely rare. This will determine if the neutrino is its own antiparticle.
One of the main concerns for these rare event experiments is the presence of backgrounds,
which could mask the signals of interest. This thesis will focus on 222Rn, one of the most
common backgrounds due to its excessive prevalence in the mine environment. Radon decays
into daughter nuclei where the energies lie within the region of interest for neutrino-less double
beta decay. The detector is housed in a large cavity that is filled with ultrapure water and has
a nitrogen cover-gas in order to avoid contamination. Radon Assay is a technique that was
developed for the original SNO experiment to keep track of the radon content within the cavity
and the covergas systems. The Assay system itself is well calibrated with low backgrounds.
Assays are performed frequently at different positions of the cavity and cover-gas to monitor
the radon levels. During a radon assay, radon is cryogenically trapped, concentrated, and
shared into a ZnS coated Lucas cell for a period of time and known amount of flow. This
Lucas cell is then connected to a PMT, which detects the decayed alphas that are used to
calculate the number of radon atoms in the assay. This technique is a crucial part of measuring
and monitoring the low backgrounds for the experiment which is then verified from the in-situ
Bi214 analysis for accuracy.Master of Science (MSc) in Physic
Optimisation and use of bivalve mollusk shells as monitors and indicators for chemical and biotic stress detection
Get PDFBivalve mollusk shells are used traditionally as monitors for chemical stress detection via
elemental analysis of a whole multilayered shell or its single layers. The central shell part, as
suggested by some authors, has a perspective to be used as a bioarchive of environmental
records. Shells as indicators of water pollution with xenobiotics and animals’ infestation with
pathogens/parasites are cursorily studied. The aim of this dissertation was to increase our
knowledge of bivalve shells, as environmental indicators and monitors, based on their
preservation and micromorphology data. Studied chemical stressors include silver and copper in
dissolved and nanoparticulate form, and actinides (
232Th, 241Am) in dissolved form. Studied
biotic stressors include pathogenic photosynthetic microalgae Coccomyxa sp. and unknown shell
borers. Shells obtained from control and contaminated/infested freshwater and marine bivalves,
and shells obtained after laboratory and field-based experiments, were examined by optical,
digital and electron microscopy, mass spectrometry, X-ray powder diffraction, γ-spectrometry
and α-tracks autoradiography. Where applicable, bivalves’ soft tissues and biological liquids
were examined. The most important findings are: 1, the amount of pollutants on the external
shell surface depends on its preservation and micromorphology; 2, doughnut shape structures
(DSS) were found on the surface of aragonite tablets (nacre) if mussels were exposed to low
concentrations of silver (in the form of ions and nanoparticles); 3, infestation of M. edulis with
pathogenic photosynthetic microalga Coccomyxa sp. promotes the formation of L-shaped shell
deformity (LSSD); 4, infestation with Coccomyxa was experimentally confirmed for mussels
pre-exposed to copper; 5, the old (previously secreted) layers of nacre can be transformed to
aragonitic lenses of prisms (ALPs) due to early unknown physicochemical mechanism in
response to shell attacks with boring organisms. In order to improve environmental monitoring protocols which use bivalves it was recommended: (a) to collect marine blue mussels (Mytilidae)
with eroded external shell surface, whereas shells of freshwater unionid and dreissenid bivalves
must have intact fleecy periostracum; and (b) to use the presence of DSS, LSSD and ALP as
indicators of water pollution with metals, metals/pathogenic alga, and shell-borers, respectively.Doctor of Philosophy (PhD) in Material Science
The Humber and its currents: informing public place through historical analysis
Get PDFFollowing the groundwork established by scholars such as
Lucy Lippard, Svetlana Boym, Robin Wall Kimmerer, and Julie
Eizenberg, this thesis aims to uncover a practical approach to
the curation of public places of belonging in post-industrial
society. More specifically, it focuses on the use of history as a
tool for placemaking amidst colonial structures of indifference,
alienation, and displacement In Toronto, Ontario, Canada.
The research consisted of a thorough social, ecological, and
historical analysis of the Humber River and the surrounding
communities, with a particular focus on the City of Toronto
and four adjacent neighbourhoods within its urban watershed.
The proposed architectural intervention is a response to the
social and ecological issues identified in the paper across a
spectrum of nested scales. At the most architectural scale,
the proposed building addresses the social needs of the
local communities, providing facilities for children, youth,
parents, and the elderly to learn through participation in
their environment, while also providing opportunities for
community organizers to lead and to educate the public.Master of Architecture (M.Arch
Spatial ecology and variables influencing habitat use and fitness proxies of Eastern hog-nosed snakes (Heterodon Platirhinos) within an anthropogenic landscape
Get PDFChanges in environmental conditions and threats from human activities present unique
challenges to persistence and management of wildlife populations at range peripheries. For
successful recovery and conservation of reptile species at risk (SAR), basic knowledge of their
life histories and ecologies must be understood. Such basic information was lacking for a
recently reported population of eastern hog-nosed snakes (Heterodon platirhinos) in
southwestern Ontario. To successfully meet government-mandated recovery actions for the
population of Threatened snakes, I investigated whether hog-nosed snakes’ space use, habitat
preferences, and proxies of fitness were impacted by widespread anthropogenic activity in Huron
County, Ontario. I estimated movement and home range size (mean ± SD) from locations of hognosed snakes (n = 10) outfitted with radio transmitters from the 2018 to 2020 active seasons, and
then calculated using kernel density estimates (KDE) and minimum convex polygons (MCP). I
evaluated habitat selection at three scales (i.e., exact, local, and landscape) using resource
selection function models and ranked models using Akaike’s Information Criterion corrected for
small sample sizes. Proxies of fitness I assessed included quantification of thermal habitat from
hourly ground temperatures and snake body condition estimated from residuals of body mass on
snout-vent length regressions. I found that when compared to conspecific populations throughout
their range, Huron County snakes moved greater distances (49 ± 13 m per day, 127 ± 41 m per
move) within larger-sized home ranges (64 ± 30 ha), as well as were heavier and in better body
condition compared to conspecific populations near Point Pelee, Ontario. At the coarsest scale, I
found that occurrence of snakes in Huron County was positively associated with forest, beach,
and old field habitats, while at finer scales, habitat characteristics with structural complexity,
cover, and thermal suitability influenced snake occurrence. While proxies of snake fitness did not appear imminently impacted by human activity in Huron County, widespread disturbance did
influence how hog-nosed snakes used the landscape: snakes moved greater distances (than those
in conspecific populations) to use pockets of natural habitats that were thermally suitable and
structurally complex. To ensure effective management of the population stewardship efforts
should focus on protection and enhancement of snake habitat and have such actions follow
recommendations from this study. My study exemplifies the complex nature of SAR
management in Ontario and how understanding space use, habitat selection, and fitness proxies
are important to successfully conserving and recovering a snake species at risk.Master of Science in Biolog
Pairwise comparisons method utilizing microservices
Get PDFOperations research has a sub-discipline called multi-criteria decision-making.
In decision-making, it explicitly considers numerous contradictory criteria.
In other words, when choosing the best solutions is challenging. On solving
multi-criteria decision-making issues, the consistency-driven pairwise comparisons approach is useful. It provides an elegant method for identifying and
resolving inconsistency by comparing and rating. It is based on the Koczkodaj inconsistency indicator, which was proposed and named after prof. W.
W. Koczkodaj and is used as a validation approach. In knowledge-based systems and data mining, the consistency-driven pairwise comparisons method
may be used as a strong knowledge acquisition strategy.
The thesis covers an application built with spring boot microservices, angular, swagger, highcharts, and cloudemersive api's. These libraries and
frameworks are used to create web applications that can operate both standalone and on clusters. This application may be used in conjunction with
any expert or knowledge management system.Master of Science (MSc) in Computational Science
The second regreening: mitigating urban sprawl in the South End of Sudbury beginning with the regeneration of the Southridge Mall
No full textThe thesis aims to reevaluate the sprawling development pattern
that has plagued Sudbury, Ontario. Contrasting city-led regreening
initiatives with poorly thought out and executed development, the
project asks what would happen if development mutually supported
both the environment and the community in the South End of Sudbury.
Taking cues from New Urbanists, local environmentalists, and
historians, the project will reinstate culturally significant architecture
and introduce walkable urban infrastructure that prioritizes active
modes of transportation. Building upon existing trail networks and
considering the ecology of the commercial center of the South End,
known as the “Four Corners,” a new village center will regenerate
the underutilized space.Master of Architecture (M.Arch
Genetic algorithm framework for stochastic open pit mining optimization problems
No full textGenetic algorithm (GA) is a metaheuristic evolution algorithm that has been applied in the
area of combinatorial optimization problems. One of these areas of optimization is mine
production scheduling. Mine production scheduling is the process of determining the
sequence of block extractions over a period of time that will yield the maximum net present
value (NPV) for the mining operation subject to a set of constraints. The block extraction
sequence needs to occur under certain resource constraints, which presents an NP-hard
problem. NP-hard problems are computationally intractable and complex to solve for large-
scale problems using exact mathematical models such as Mixed Integer Linear
Programming (MILP) and Stochastic Mixed Integer Linear Programming (SMILP).
In the mining production scheduling problem, the conventional approach is to use a single
interpolated orebody model as the basis for production scheduling. This approach, however,
does not consider grade uncertainties. These uncertainties have a significant impact on the
NPV and can only be accounted for when modelled as part of the optimization problem.
However, modeling these as part of the optimization problem increases the complexities
associated with the production scheduling. In this research, a metaheuristic optimization
framework based on GA was designed and implemented to solve the NP-hard large-scale
open pit production scheduling (OPPS) problem. The problem definition and the resource
constraints were formulated and optimized using a specially designed mining-specific GA.
A multiple chromosome encoding technique was used in the GA to handle partial block
processing to obtain a near-optimal solution.
Two case studies from an oil sands dataset were presented in this research. A stochastic
formulation (SGA) of the OPPS problem to incorporate grade uncertainty based on equally
probable orebody realizations was considered and optimized with the GA framework. A
deterministic approach (DGA) to the OPPS problem that did not consider grade variability
was also presented. The NPV and computational time from the DGA scenario were
compared to a MILP model solved with CPLEX and the SGA scenario was compared to a
SMILP model solved with CPLEX as a means to validate and analyze the GA results. There
was a 53.6% improvement in the computational time for the DGA compared to the MILP model with CPLEX in Case Study 1. However, the NPV was within 5.1% of the MILP
model with CPLEX. The SGA model for Case Study 1 generated an NPV within 5.3% of
the NPV of the SMILP model with CPLEX. Conversely, the result of the SGA model was
generated in a computational time that was 75.2% better than the SMILP model with
CPLEX. For Case Study 2, whereas the MILP model generated NPV of 9,142 M at 12.9% gap after
1.3 hours. Additionally, while the SMILP model was at a gap of 101% after 28 days, the
SGA model generated NPV of $10,045 M at 10.6% gap after 1.5 hours.Master of Applied Science (MASc.) in Natural Resources Engineerin
Chronic obstructive pulmonary disease (COPD): the Impact of occupational hazards in the minerals industry
No full textThis study aimed to explore the psychosocial, occupational, financial, and physical impact of
chronic obstructive pulmonary disease on underground workers in the minerals industry in
Northeastern Ontario, describe their experiences with the Ontario workers’ compensation claim
process. This study also aimed to communicate experiences of physicians and union workers with
underground mineral workers diagnosed with COPD as an occupational illness and the Ontario
workers’ compensation claim process experience. Data were collected via semi-structured
telephone interviews with 16 underground mineral workers with occupational COPD, four union
compensation representatives and four physicians (two primary care and two specialists).
Interviews were transcribed verbatim, and a thematic analysis was completed. Examples of themes
that arose from the findings of the underground mineral workers’ COPD group included: 1) COPD
affects quality of life, 2) I smoked; I did not think I could get compensation, 3) the compensation
process is a joke, 4) doctors do not know anything, and 5) working in the mine is a dirty job – we
did not know any better. Themes from the union compensation representatives and physicians
included: 1) additional support resources required, 2) smoking cessation is essential, 3) the
compensation claim process is challenging, 4) occupational diseases are challenging to prove, and
5) occupational COPD is costly. These results suggested that advocacy is critical to ensuring
underground workers receive the support they need to obtain approval of a compensation claim.
The results also illustrated the need for further education about the ability to document and support
an occupational illness for physicians and worker’s compensation caseworkers involved in caring
for an underground mineral worker diagnosed with occupational COPD. Continued research about
occupational diseases and the compensation claim process for those with COPD is required to
address the barriers and challenges experienced.Doctor of Philosophy (Ph.D.) in Rural and Northern Healt
Correlation of breast cancer biology and x-ray scatter data
No full textWide angle x-ray scatter (WAXS) imaging can potentially be used to diagnose ductal carcinoma in situ (DCIS) in breast biopsies. In this work, WAXS signals are used to model healthy and diseased breast tissue. It is accomplished by analysis of the breast tissue’s differential linear scattering coefficients ‘μₛ’. The tissue samples are assumed to consist of varying amount of fat, stroma and cells and their μₛ coefficients can be expressed by the following sum: μₛ(x) = afat • μₛ fat(x) + astr •μₛ str(x) + acell •μₛ cell(x), where x= (1/ λ) sin(θ/2) is the momentum transfer argument, λ is the x-ray wavelength and θ is the scatter angle. Data for breast tissues was taken from literature and that for stroma was estimated using histology studies. The fractional volumes of each of the three components (afat, astr, acell) were evaluated using singular value decomposition (SVD). Fitting results suggest cancer consists of 44% cells as compared to only 8% and 7% for normal and benign tissue, respectively. These results support the argument that an uncontrolled proliferation of cells is the hallmark of cancer. The fat decreases from 56% (normal) to 26% (benign) and to only 3.4% in cancer. This is justified by the fact that invasive ductal carcinoma cells use fat to fuel their growth and spread. Stromal increase from 35% in normal to 67% in benign suggest that benign diseases such as fibroadenoma are characterized by a surge in fibrous tissue. The model predictions of the compositions for normal, benign and malignant tissue are promising. It gives insight into how cancer interacts with its microenvironment.
While scatter studies on cells and fat have been done in the past, not much is known about stroma in the same context. Studies show that stroma promotes cancer growth and metastasis, making it an important component to focus on. The second part of this research works on this aspect. A model for stroma made up of 80% collagen, 10% elastin and 10% versican is introduced. μs for stroma is then determined using Independent Atomic Model (IAM) approximation. The scattersignal obtained via this newly introduced stroma model matches with the previous estimation, mainly at the higher values of momentum transfer values. This is because IAM fails at the lower regime due to interference phenomenon. It is observed that the scatter values obtained using IAM are not very sensitive to the change in composition of stroma. In most of the cases, the percentage change with reference to the original model is less than 1%. In the event in which elastin is considered to be the major constituent, a difference of 2.41% to 3.49% is seen. This model gives important information about the structure and function of stroma and highlights its role in cancer progression
mînawâcihiwewi-ne-wîkiwnan / Healing our home: buildings of the land
No full textIndigenous people have always had a strong connection to the Land, as she is our Mother
Earth. The Land grounds Indigenous people as our culture reflects the Land we come from.
It reflects our language, our traditional teachings and values, and our built structures. The
Moose Cree people understood the world as they are all related to Mother Earth’s creations.
Everything is interconnected with one another to achieve harmony and balance. This is the
Cree way of life which is called ililiwi-pimâtisîwin. The traditional way of life for the Moose Cree people significantly changed during the 1600s when the British established a fur trading post
on Moose Factory Island and soon after the Anglican church took over the community. Our
home stopped reflecting who we were as Moose Cree people and how we lived. This thesis
entitled mînawâcihiwewi-ne-wîkiwnan / Healing Our Home: buildings of the Land focuses on
a design that reflects the Moose Cree people and our Cree way of life. Our home refers to
not only the built structure of where we live, but also to our ancestors, our communities, and
our home-lands. Our home is connected with the Land which is connected to all of Mother
Earth’s creations.Master of Architecture (M.Arch