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Recent Submissions

Access status: Open Access ,
Framework and Application of a Practical Robustness-Oriented Bridge Upgrade Strategy for Trusses (ROBUST): Supplementary Material
(American Society of Civil Engineers, 2026) Steeves, Edward; Oudah, Fadi
Access status: Open Access ,
A Whale With No Name: Search for an unknown long-duration beaked whale (Cetacea; Ziphiidae) signal across ocean basins
(2025-12-28) Runte, Kiersten; Not Applicable; Master of Science; Department of Biology; Not Applicable; n/a; Not Applicable; Bruce Martin; Andy Horn; David Barclay; Hal Whitehead
Beaked whales (Cetacea: Ziphiidae) are known for producing frequency-modulated (FM) echolocation signals that are characteristic of each species, yet several species still lack confirmed FM signal descriptions. A distinctive FM signal, long in duration, and occurring only at night, has previously been documented in the North Pacific, the western Gulf of Mexico, and the Gulf of Guinea, but its broader distribution has not been assessed. Here, carried out is a basin-wide analysis of numerous passive acoustic monitoring projects to identify additional regions where this signal is present. Our dataset comprised 19 monitoring efforts (156 total datasets) spanning latitudes from 72° N to 42° S. An automated detector-classifier (per file Precision = 1.00 and Recall = 1.00) was run on all audiofiles to identify possible detections, which were subsequently reviewed and confirmed manually. We report the presence of this FM signal in five previously unrecognized areas: along a glider transect (512 kHz) near the Canary Islands; on three bottom-mounted recorders (250–512 kHz) off Western Australia; and from a single detection on Blake’s Plateau in the southeastern United States. Across all monitoring sites, detections occurred only during local nighttime hours and were not observed at latitudes higher than 29° N or 19° S. The signal’s median centre and peak frequencies ranged from 51 to 67 kHz, its median duration from 500 to 630 μs, and its −10 dB bandwidth from 19 to 28 kHz. This FM signal remains the longest known among both identified and unidentified beaked whale FM signal types. Although the producing species has yet to be determined, the signal’s temporal and spectral features were remarkably consistent across ocean basins. These results extend the known distribution of this unique FM signal and highlight the value of broad, cross-regional acoustic collaborations in uncovering previously unrecognized regions of beaked whale vocal behaviour and biogeography.
Access status: Open Access ,
Confronting Acoustic Data Scarcity: A Physics-Informed Approach to Trustworthy Machine Learning in Canada's Arctic
(2025-12-28) Thomson, Dugald; Yes; Doctor of Philosophy; Department of Oceanography; Not Applicable; Peter Gerstoft; Yes; Dale Ellis; Stan Dosso; JF Bousquet; Sarah Fortune; David Barclay
This thesis presents a novel, data-centric framework for building trustworthy artificial intelligence for passive acoustic monitoring in the Arctic, a region increasingly challenged by climate change and geopolitical pressures. The research addresses model brittleness in ship-radiated noise classification, framing it as a data problem that can be solved through a systematic, iterative process of data exploration, diagnosis, and augmentation. A detailed analysis of ship-radiated noise using horizontal line array element data provides a characterization of the complex variability of acoustic signatures. The thesis quantifies the horizontal directionality of radiated noise from individual ships and the broad-scale impact on the ambient soundscape, leveraging a unique data opportunity presented by the COVID-19 pandemic. Using these insights, a human-in-the-loop methodology is developed to diagnose the specific failure modes of a custom deep neural network classifier. This is achieved by visualising how real-world variability, such as source-receiver range and operational state changes, manifests in the model's learned feature space. The thesis culminates by demonstrating a physics-informed data augmentation strategy as the solution to data scarcity and diagnosed failures. Through the generation of targeted, high-fidelity synthetic data, this approach measurably improves classifier robustness on unseen real-world data, providing a validated methodology for developing reliable automated passive acoustic monitoring systems in complex environments.
Access status: Embargo ,
COLLOIDAL QUANTUM DOTS-ASSISTED HYBRID PHOTOCATALYST FOR WASTEWATER TREATMENT
(2025-12-30) Madhu, Swedha; Not Applicable; Master of Science; Faculty of Agriculture; Not Applicable; NA; Yes; Dr Lord Abbey; Dr Kuljeet Grewal; Dr Gurpreet Singh Selopal
Water pollution from toxic organic dyes and industrial effluents poses a severe threat to ecosystems and human health, underscoring the urgent need for sustainable, efficient wastewater treatment technologies. Among various approaches, photocatalysis has emerged as a promising technique for pollutant degradation due to its cost-effectiveness and environmental compatibility. However, the performance of conventional photocatalysts is hindered by several critical limitations, including poor light absorption capability, toxicity of heavy-metal-based catalysts, rapid e⁻/h⁺ recombination, and limited recyclability. This thesis aims to overcome these challenges by developing eco-friendly colloidal Quantum Dots (QDs) based nanohybrids integrated with one-dimensional (1D) and zero-dimensional (0D) nanomaterials to achieve efficient charge separation, broadened light absorption, and improved photocatalysis. Furthermore, the influence of external stimuli, including magnetic fields (MF), electric fields, and piezoelectric effects, was investigated to enhance the photocatalytic degradation efficiency of toxic pollutants. Firstly, a novel Cu:Zn-In-Se2 QDs decorated Fe3O4 nanorods mesoporous films were employed for the photocatalytic degradation of methylene blue (MB) under the influence of an external MF. The optimized hybrid nanohybrid photocatalyst achieved a remarkable 99.96% degradation efficiency, representing a 49% improvement over the control Fe3O4 photocatalyst (67.01%). This enhanced performance was attributed to the synergistic effect of the broad light absorption of Cu:Zn-In-Se2 QDs/Fe3O4 and the efficient carrier dynamics facilitated by the Lorentz force in the presence of the MF. Additionally, the toxicity of treated methylene blue (MB) water was evaluated using Brassica oleracea (kale) as a model plant system. Plants irrigated with treated water exhibited superior growth compared to those irrigated with MB-contaminated water, confirming the reduced toxicity of the treated water and demonstrating its potential for safe agricultural reuse and sustainable wastewater management. Secondly, a hybrid photocatalyst composed of Mn:CuInSe2 QDs integrated with a mesoporous TiO2 film photoanode was developed and evaluated for the simultaneous photoelectrochemical degradation of Rhodamine B (RhB) and hydrogen generation. The optimized hybrid Mn:CuInSe2 QDs/TiO2 nanohybrid photocatalyst achieved a remarkable 93.31% degradation efficiency of RhB at an external bias of 1.4 V and a photocurrent density of ~4 mA cm-2 at 0.8V vs RHE. The results highlight the potential of Mn:CuInSe2 QDs/TiO2 nanohybrid as a dual-function photocatalyst for efficient and fast wastewater treatment and clean fuel production. Thirdly, the piezoelectric degradation of pollutants was investigated using ZnSnO3-based nanomaterials, demonstrating the capability of piezo-catalysis to degrade organic contaminants effectively. Overall, this research provides new insights into the design of novel eco-friendly Cu:ZnInSe2 QDs/ZnSnO3 nanohybrid photocatalysts and presents external-vibrational-stress-assisted photocatalysis for efficient environmental remediation and renewable energy generation.
Access status: Embargo ,
Constructing Igboness: Ethnicity, Culture, and Social Change in 20th Century Southeastern Nigeria
(2026-12-31) Abuba, Chioma; Not Applicable; Doctor of Philosophy; Department of History; Received; Professor Bonny Ibhawoh; Not Applicable; Dr. Gary Kynoch; Dr. Jonathan Roberts; Dr. Philip Zachernuk
Contrary to the dominant binary conceptions of Igboness (Igbo cultural identity) as either invented in response to colonial rule or an essence unchanged since early times, it is a dynamic, heterogenous, social construct which developed in continual dialogue with global knowledge systems and social currents. This idea is based on a study of Enugwu-Ukwu, a culturally iconic town in northern Igboland, in southeastern Nigeria, renowned as part of the nexus of Igbo culture and civilization. It traces how, over a century (1900-2000), local historical actors (chiefs, townspeople, town unions, women’s groups, etc.) engaged with local, colonial and global forces attempting to apply Omenana (Igbo cultural principles) to routinize a society undergoing the revolutionary changes of the 20th century. Using extensive archival records, oral interviews, museum collections, and primary and secondary literature, this study shows what changes occurred, who made them happen, how they achieved this, and why they tried.
Access status: Open Access ,
Investigating Turnover Intentions of Immigrant Software Engineers
(2026-01-06) Amedzor, Eyram; Not Applicable; Master of Computer Science; Faculty of Computer Science; Received; na; Not Applicable; Dr. Dirk Arnold; Dr. Lizbeth Escobedo Bravo; Dr. Rina R. Wehbe; Dr. Paul Ralph
Context: Software companies around the world rely on immigrant software engineers to fill their gaps in the workforce. However, immigrants leave their jobs at higher rates than native-born workers. Objective: Our objective is to investigate factors contributing to the increased turnover of software engineers with immigrant backgrounds. Methodology: We conducted a grounded theory study interviewing twenty software engineers with immigrant backgrounds originating from seven different countries. Results: Participants identified four primary factors that shape their turnover intentions: career stagnation, compensation, remote work preferences, and family. Social embeddedness---how connected individuals feel to their surrounding communities and institutions---served as a secondary factor, and immigration policies acted as constraints to actual turnover behavior. Recommendations: In order to reduce turnover, we recommend that organizations pay their immigrant engineers market rates, provide growth opportunities, and offer remote work options to enhance the retention of migrant engineers. For governments, we recommend implementing employer-agnostic visas, extending renewals for expiring visas, and funding programs that promote the cultural integration of new immigrants.