Physical Sciences and Mathematics Commons^™

Drone Images Afford More Detections Of Marine Wildlife Than Real-Time Observers During Simultaneous Large-Scale Surveys, Amanda J. Hodgson, Nat Kelly, David Peel

Research outputs 2022 to 2026

There are many advantages to transitioning from conducting marine wildlife surveys via human observers onboard light-aircraft, to capturing aerial imagery using drones. However, it is important to maintain the validity of long-term data series whilst transitioning from observer to imagery surveys. We need to understand how the detection rates of target species in images compare to those collected from observers in piloted aircraft, and the factors influencing detection rates from each platform. We conducted trial ScanEagle drone surveys of dugongs in Shark Bay, Western Australia, covering the full extent of the drone’s range (∼100 km), concurrently with observer surveys, with …

Investigation Of Oleic Acid As A Dispersant For Hydroxyapatite Powders For Use In Ceramic Filled Photo-Curable Resins For Stereolithography, Brendan Kennedy, Eamonn De Barra, Stuart Hampshire, Maura Kelleher

Articles

Stereolithography allows production of porous hydroxyapatite scaffolds for bone regeneration but is limited by the challenging rheology of ceramic filled resins. Oleic acid, a natural fatty acid, was applied in concentrations of 0.0–0.3 wt% to improve the rheological properties of HAp resins for the fabrication of solid cylinders and scaffolds by digital light processing (DLP) printing in a wiperless system. Bonding by chemisorption was confirmed by FTIR analysis. The powders were then incorporated into a photo-curable resin of 1–6 hexanediol diacrylate at 18–30 vol%. The shear viscosity and sedimentation rates of photocurable resins containing HAp powder decreased with increasing concentration …

Statistical Models For Decision-Making In Professional Soccer, Sean Hellingman

Theses and Dissertations (Comprehensive)

As soccer is widely regarded as the most popular sport in the world there is high interest in methods of improving team performances. There are many ways teams and individual athletes can influence their own performances during competition. This thesis focuses on developing statistical methodologies for improving competition-based decision-making for soccer so as to allow professional soccer teams to make better informed decisions regarding player selection and in-game decision-making.

To properly capture the dynamic actions of professional soccer, Markov chains with increasing complexity are proposed. These models allow for the inclusion of potential changes in the process caused by goals …

Spatial And Temporal Characteristics Of Historical Surface Climate Over The Northwest Territories, Canada, Bhaleka D. Persaud

Theses and Dissertations (Comprehensive)

Climate change is putting many of the Northwest Territories (NWT) ecosystems, its people and animal populations at risk due to accelerated warming, permafrost thaw, and changing precipitation regimes. As the NWT continues to warm, at disproportionately higher rates when compared to the rest of Canada, threats to the stability of NWT’s ecosystems are expected to increase. Consequently, understanding how climate warming has changed historically and its implications on natural ecosystems requires point-to-region-specific, long-term climatic data to elucidate important drivers of observed changes relevant to decision makers at community, Indigenous, Territorial and Federal government levels. However, in situ climate data are …

The Design And Characterization Of Gold Nanoclusters As Elementary Building Blocks, Heather Gaebler

Theses and Dissertations (Comprehensive)

Gold nanoclusters with diameters in the quantum size regime (< ~2 nm) are promising building blocks for the design of novel nanomaterials as they exhibit unique size-dependent properties that can be altered and fine-tuned. The research outlined in this PhD thesis employs density functional theory to construct and analyze small ligand-protected cage and rod-shaped nanoclusters. Chapter 2 reports stable halide-protected gold nanocages that were engineered to have a closed-shell valence electron count of 18. This study finds that nanocages comprised of 19 and 20 gold atoms can be converted into stable magic number species containing 18 valence electrons by modifying their charged states via adsorption of halide ligands to the cage’s surface. Chapter 3 reports stable ligand-protected gold nanoclusters with a tetrahedral Au₄ core that were engineered to have a closed-shell valence electron count of 2. This study investigates the structural and electronic effects of halide and alkoxy ligands on the tetrahedral nanocluster and concludes that the results support the broader conclusion that it’s possible to fine-tune the stability and electronic properties of small gold nanoclusters using appropriate ligands. Chapter 4 reports stable gold nanorods that have diameters in the quantum regime that were constructed from elementary building blocks that contain “halide-staples”. This study presents different orientations of the “halide-staple” motifs on …

Contrasting Seasonal Cycling Of Arsenic In A Series Of Subarctic Shield Lakes With Different Morphometric Properties, Jeremy Harbinson

Theses and Dissertations (Comprehensive)

The subarctic shield near Yellowknife, Northwest Territories (NWT), is populated with thousands of small lakes (<1.5 km²) and several large lakes. Historic mining activities in the region have left a legacy of environmental impacts and widespread arsenic (As) contamination in both aquatic and terrestrial environments. In particular, several small subarctic lakes near Yellowknife have been previously documented to be contaminated with high levels of As. Subarctic lakes are characterized by seasonal ice-cover that can persist for more than half of the year, yet little is known about the under-ice spatial and seasonal dynamics of As cycling. The objective of …

The Effect Of Age, Syntax Complexity, And Cognitive Ability On The Rate Of Semantic Illusions, Sara Anne Goring

CGU Theses & Dissertations

Semantic illusions are recognition errors that occur when an individual fails to notice that information contradicts their prior knowledge (Barton & Sanford, 1993; Erickson & Mattson, 1981). For example, after hearing the question, “If a plane crashes while flying over state lines, where should the survivors be buried?” many start to consider the legality or appropriateness of the scenario despite knowing “survivors” should not be buried. Having more knowledge does not necessarily prevent individuals from overlooking illusory information/misinformation. Older adults tend to have greater crystallized intelligence than young adults, yet these age groups appear to detect illusory information at equivalent …

On Symmetric Operator Ideals And S-Numbers, Daniel Akech Thiong

CGU Theses & Dissertations

Motivated by the well-known theorem of Schauder, we study the relationship between various s-numbers of an operator T and its adjoint T∗ between Banach spaces. For non-compact operator T ∈ L(X, Y ), we do not have a lot of information about the relationship between n-th s-number, sn(T), with sn(T∗ ), however, in chapter 2, by considering X and Y , with lifting and extension properties, respectively, we were able to obtain a relationship between sn(T) with sn(T∗ ) for certain …

Graph-Based Acoustic Clustering And Classification, Justin Youngho Sunu

CGU Theses & Dissertations

The rapid growth of audio data collection in various domains necessitates advanced techniquesfor efficient analysis and classification. This dissertation proposes new approaches for categorizing acoustic data, using both unsupervised and semi-supervised learning methods. Starting with raw audio, we preprocess the signal to segment it into time windows, each of which we consider as an independent data point. We use the short-time Fourier transform to describe the signal in a given time window as a set of Fourier coefficients. We interpret the resulting frequency signature as a high-dimensional feature description of each data point. We then develop a graph-based approach for …

Assessment Of Stream Metabolism And Associated Environmental Drivers In The Greiner Lake Watershed, Nunavut, Canada, Nicole Gotkowski

Theses and Dissertations (Comprehensive)

Stream metabolism is an ecological process that can be monitored to assess carbon cycling and productivity within a stream ecosystem. GPP (gross primary productivity) is measured as oxygen produced by autotrophs and ER (ecosystem respiration), which is measured by oxygen depleted by all living organisms. Complications arise when estimating GPP and ER in the Arctic because most methods require a period of darkness when GPP ceases, however, summer regimes of photosynthetically active radiation (PAR) do not reach zero. Furthermore, natural diffusion of oxygen from the atmosphere (k) must be accounted for but this requires extensive field work, thus posing problems …

Nitrogen: Both A Potential Stimulator And Suppressor Of Cyanobacterial Blooms In Temperate Lakes, Catherine Goltz

Theses and Dissertations (Comprehensive)

Cyanobacterial blooms are complex phenomenon that are impacted and controlled by various factors such as lake depth, air temperature, wind, and nutrient loading. Nutrients such as phosphorus, nitrogen and iron all have very differing effects on cyanobacterial blooms. While phosphorus and iron are known to drive cyanobacterial biomass, nitrogen has been observed to have a direct impact on toxin synthesis. Nitrogen exists in the environment in many different forms such as atmospheric N₂, in inorganic forms such as nitrate and ammonium as well as in organic forms such as urea which can all affect cyanobacterial bloom development differently. …

Winter Dynamics Of Storm Water Management Ponds And Winter Tolerance In Three Aquatic Plant Species, Patrick Strzalkowski

Theses and Dissertations (Comprehensive)

The vast majority of the research into the performance of stormwater management ponds (SWMPs) has been performed in warm regions or during the warmer seasons in temperate regions. It is presumed that SWMPs are inactive in the winter as any potential stormwater is trapped in snow and ice. The main goal of this thesis was to test this presumption and to study the dynamics and performance of three SWMPs during the winter. Remote water level loggers were installed into the three SWMPs and daily grab samples from the influents and effluents were taken and analyzed for total phosphorus (TP), chloride, …

Dynamical Aspects In (4+1)-Body Problems, Ryan Gauthier

Theses and Dissertations (Comprehensive)

The n-body problem models a system of n-point masses that attract each other via some binary interaction. The (n + 1)-body problem assumes that one of the masses is located at the origin of the coordinate system. For example, an (n+1)-body problem is an ideal model for Saturn, seen as the central mass, and one of its outer rings. A relative equilibrium (RE) is a special solution of the (n+1)-body problem where the non-central bodies rotate rigidly about the centre of mass. In rotating coordinates, these solutions become equilibria.

In this thesis we study dynamical aspects of planar (4 + …

Mechanistic Studies Of Co2 Electrochemical Reduction (Co2er) On Cu And Cuo Nanoparticles With In-Situ Atr-Ftir Spectroscopy, Jason Hsu

Theses and Dissertations (Comprehensive)

Global climate change is a major challenge facing the world in the 21st century. This environmental crisis originated from excess amounts of atmospheric carbon dioxide (CO2) released from burning fossil fuels. One promising remediation method to decrease atmospheric CO2 levels is called carbon dioxide electrochemical reduction (CO2ER). In CO2ER, the CO2 gas undergoes chemical reduction to other hydrocarbon fuels. For CO2ER to take place, an energy source and a catalyst are needed. In this thesis, three aspects of CO2ER were investigated using attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy coupled with other surface sensitive characterization tools. First, we studied …

Properties Of (Claw, 4k₁, Bridge)-Free Graphs, Taite Lagrange

Theses and Dissertations (Comprehensive)

Given a set H of graphs, a graph G is H-free if it does not contain any graph in H as an induced subgraph. The complexity of the colouring problem is known when H is a set of graphs on four vertices, with three exceptions. One of those exceptions is the case of {claw, 4K₁}-free graphs, for which our classes of {claw, 4K₁, bridge}-free and {claw, 4K₁, bridge,C₄-twin}-free graphs are subclasses.

The original goal of this work was to prove that {claw, 4K₁, …

The Dynamic Relationship Between Permafrost And Landcover In Northwestern Canada’S Discontinuous Permafrost Zone, Olivia Carpino

Theses and Dissertations (Comprehensive)

Northwestern Canada’s subarctic is among the most impacted regions in the world as it is experiencing rapid climatic and environmental change. As a result, northwestern Canada has been experiencing region-wide permafrost thaw and disappearance, both of which are also occurring at unprecedented rates. Permafrost temperatures in the Taiga Plains have been warming steadily over the last several decades, which has been particularly detrimental across its lower latitudes of the discontinuous permafrost zone where the permafrost is already relatively thin and warm. These factors indicate that permafrost in the southern Taiga Plains may be in a state of disequilibrium with the …

Enzymatic Removal Of Diclofenac And Aceclofenac From Synthetic Wastewater By Soybean Peroxidase, Sarah Pishyar

Electronic Theses and Dissertations

Pharmaceutical medications that are a class of emerging contaminants have been detected in wastewater treatment facilities' influent and effluent, and they have reached water sources in amounts ranging from ng/L to ug/L. They threaten the environment and non-target life. Soybean peroxidase (SBP)-catalyzed process was studied to remove two non-steroidal anti-inflammatory drugs (NSAIDS) diclofenac and aceclofenac through enzymatic oxidation from synthetic wastewater. SBP can be extracted from soybean hulls, a by-product of the soybean industry. First, the experiments studied the viability of SBP-catalyzed removal on these two compounds, then the operational parameters including pH, the molar ratio between hydrogen peroxide and …

Functional Characterization Of Hodi, A Dead-Box Rna Helicase In Toxoplasma Gondii, Using Rna-Protein Tethering Assay, Ronaldo Eid

Electronic Theses and Dissertations

Toxoplasma gondii, an obligate intracellular apicomplexan parasite, is the causative agent of toxoplasmosis which has serious complications in immunocompromised individuals and in offspring of infected mothers. Central to the parasite’s pathogenesis and transmission is its adaptation to various forms of cellular stress. A conserved stress response by Toxoplasma gondii is translational control induced by phosphorylation of TgIF2α, during which non-translating mRNAs accumulate in messenger ribonucleoprotein (mRNP) granules that disassemble upon stress relief. DEAD-box RNA helicases are candidates involved in the regulation of mRNP granules and also function in translational control. In this study, it was shown that the flanking …

Assessment Of Water Quality Index, Light Attenuation, And Nutrient Sequestering By Submerged Aquatic Vegetation In The Detroit River, John Scannell

Electronic Theses and Dissertations

This thesis assessed water quality – submerged aquatic vegetation interactions in the Detroit River. Submerged aquatic vegetation provides essential ecosystem services that support aquatic biodiversity and regulating ecosystem services such as carbon sinks, purifying water and nutrient cycling. Chapter 2 explored how degraded water quality in the Detroit River limits submerged aquatic vegetation via light limitation. A water quality index and light extinction coefficients were measured at 21 sites along with installation of in-situ water quality sondes at 4 sites to measure water quality at high temporal resolution. The river wide median euphotic depth was estimated to be 1.30 m, …

Webcam-Based Optical Mark Reader For Grading Assessments, Muhammad Fahad Zafar

Electronic Theses and Dissertations

Optical Mark Recognition (OMR) is a process of retrieving information from the forms where users put marks in particular locations. OMR technique has been improved significantly since its inception, moving from specialized hardware-based solutions to more adaptable and sophisticated software-based solutions using a scanner. Recently, webcam-based software solutions have emerged because of their affordability and ease of use. In this thesis, we propose an improved webcam-based OMR solution for grading the student tests given on a specifically formatted answer sheet. We apply various image processing techniques to achieve effective grading, resolving technical problems stemming from multiple factors like image orientation, …

Sediment Microbial Community Diversity And Function In Response To Legacy And Prevailing Pollutants In Southern Ontario Watersheds, Nicolas Falk

Electronic Theses and Dissertations

Managing and mitigating point and non-point contamination to freshwater resources depends on reliable and sensitive monitoring of ecosystem health. Microorganisms in surface waters and sediments respond rapidly to anthropogenic disturbances, making them valuable bioindicators of human-induced landscape change. However, there lacks a baseline understanding of microbial community composition and function in industrially and agriculturally impacted regions of the Great Lakes. Without a reference state of microbial diversity and activity, future investigations seeking to integrate microorganisms into ecosystem assessments will lack context. Using genomic tools and measurements of chemical and nutrient contaminants, this thesis provides case studies of microbial community responses …

Consequences Of Environmental Manipulation On Behavioural And Neuromorphological Plasticity As It Relates To The Reintroduction Of Atlantic Salmon (Salmo Salar) To Lake Ontario, Ali I. Mokdad

Electronic Theses and Dissertations

The reintroduction of imperilled species has become an important tool in conservation biology and relies on the captive-rearing of remaining individuals, or a subset thereof, as a lifeline to prevent extinction. The success of reintroduction efforts has generally been low, mainly due to poor post-release performance of captive-reared animals. Captive-breeding programs tend to produce behaviourally and neurologically compromised animals that deviate from wild phenotypes and are less fit in natural settings. While genetic adaptation can account for some of the behavioural deficiencies expressed by captive-reared animals, phenotypic plasticity has been shown to play a large role. Phenotypic plasticity is generally …

Reducing Model Memorization To Mitigate Membership Inference Attacks, Sheikhjaberi

Electronic Theses and Dissertations

Given a machine learning model and a record, membership inference attacks determine whether this record was used as part of the model’s training dataset. This can raise privacy issues.

There is a desideratum to providing robust mitigation techniques against this attack that will not affect utility. One of the state-of-the-art frameworks in this area is SELENA, which has two phases: Split-AI and Distillation to train a protected model, which by giving non-members behavior to members tries to mitigate membership inference attacks.

In this thesis, we introduce a novel approach to the Split-AI phase, which tries to weaken the membership inference …

Multi-Data Source Recommendations With Derived Sequential Pattern Mining, Burhan Uddin

Electronic Theses and Dissertations

Existing multi-source RS algorithms, such as ECCF19, use item categories to extend the CF model and enhance the preference matrix. The CD-SPM19 model uses item ontology to derive semantic similarity information to enrich the collaborative filtering (CF) step. The HPCRec18 model derives a consequential bond between click to purchase to predict preferences for users with no purchase history. Finally, the HSPRec19 model using the historical sequential purchase database (SHOD) algorithm, derives sequential purchase patterns from historical purchase data. It then uses the consequential bond in mined patterns to improve the user-item matrix for CF. None of these systems use historical …

Impact Of Spallation And Internal Radiation On Fibrous Ablative Materials, Raghava Sai Chaitanya Davuluri

Theses and Dissertations--Mechanical Engineering

Space vehicles are equipped with Thermal Protection Systems (TPS) that encounter high heat rates and protect the payload while entering a planetary atmosphere. For most missions that interest NASA, ablative materials are used as TPS. These materials undergo several mass and energy transfer mechanisms to absorb intense heat. The size and construction of the TPS are based on the composition of the planetary atmosphere and the impact of various ablative mechanisms on the flow field and the material. Therefore, it is essential to quantify the rates of different ablative phenomena to model TPS accurately. In this work, the impact of …

Integrating Remote And In-Situ Techniques To Quantify Landscape Evolution, Matthew Maclay

Dartmouth College Master’s Theses

With the increasing availability and resolution of remote sensing techniques, the resulting data products are increasingly being applied to answer societally relevant questions regarding quantifying the effects of climate change, mitigating natural hazards, and understanding landscape changes over varying temporal and spatial scales. While the power and potential for such large-scale, efficient, and cost-effective surveys are undeniable, a thorough understanding of any environment requires that remotely sensed data are ground-truthed or put into context with in-situ observations. In this thesis, Chapter 1 presents a literature review of Martian analog sites and discusses the importance of integrating in-situ and remote sensing …

Timing And Source Of Water Supporting Early Lakes In The Xanthe Terra Region Of Mars, Noemi A. Ortega Dominguez

Dartmouth College Master’s Theses

Whether an ancient ocean existed on Mars remains controversial. Modeling of Mars’ early climate indicates a dry and cold environment; meanwhile geologic evidence supports a wet and warm environment that potentially hosted a globally connected aquifer with a northern ocean. One geomorphic line of evidence in support of persistent standing water and a northern ocean are inferred deltaic deposits along and near the Mars dichotomy boundary. However, not all these deltaic deposits appear to have consistent delta front elevations, and many are within craters, calling into question whether these deposits formed within the same body of water or even at …

A Provable Secure And Efficient Authentication Framework For Smart Manufacturing Industry, Muhammad Hammad, Akhtar Badshah, Ghulam Abbas, Hisham Alasmary, Muhammad Waqas, Wasim A. Khan

Research outputs 2022 to 2026

Smart manufacturing is transforming the manufacturing industry by enhancing productivity and quality, driving growth in the global economy. The Internet of Things (IoT) has played a crucial role in realizing Industry 4.0, where machines can communicate and interact in real-time. Despite these advancements, security remains a major challenge in developing and deploying smart manufacturing. As cyber-attacks become more prevalent, researchers are making security a top priority. Although IoT and Industrial IoT (IIoT) are used to establish smart industries, these systems remain vulnerable to various types of attacks. To address these security issues, numerous authentication methods have been proposed. However, many …

Biofilm Formation On The Surface Of Monazite And Xenotime During Bioleaching, Arya Van Alin, Melissa K. Corbett, Homayoun Fathollahzadeh, M. Christian Tjiam, William D. A. Rickard, Xiao Sun, Andrew Putnis, Jacques Eksteen, Anna H. Kaksonen, Elizabeth Watkin

Research outputs 2022 to 2026

Microbial attachment and biofilm formation is a ubiquitous behaviour of microorganisms and is the most crucial prerequisite of contact bioleaching. Monazite and xenotime are two commercially exploitable minerals containing rare earth elements (REEs). Bioleaching using phosphate solubilizing microorganisms is a green biotechnological approach for the extraction of REEs. In this study, microbial attachment and biofilm formation of Klebsiella aerogenes ATCC 13048 on the surface of these minerals were investigated using confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). In a batch culture system, K. aerogenes was able to attach and form biofilms on the surface of three phosphate …

Catalytic Pollutant Upgrading To Dual-Asymmetric Mno2@Polymer Nanotubes As Self-Propelled And Controlled Micromotors For H2o2 Decomposition, Yangyang Yang, Kunsheng Hu, Zhong-Shuai Zhu, Yu Yao, Panpan Zhang, Peng Zhou, Pengwei Huo, Xiaoguang Duan, Hongqi Sun, Shaobin Wang

Research outputs 2022 to 2026

Industrial and disinfection wastewater typically contains high levels of organic pollutants and residue hydrogen peroxide, which have caused environmental concerns. In this work, dual-asymmetric MnO2@polymer microreactors are synthesized via pollutant polymerization for self-driven and controlled H2O2 decomposition. A hollow and asymmetric MnO2 nanotube is derived from MnO2 nanorods by selective acid etching and then coated by a polymeric layer from an aqueous phenolic pollutant via catalytic peroxymonosulfate (PMS)-induced polymerization. The evolution of particle-like polymers is controlled by solution pH, molar ratios of PMS/phenol, and reaction duration. The polymer-covered MnO2 tubing-structured micromotors presented a controlled motion velocity, due to the reverse …