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Recent Submissions

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.
Access status: Open Access ,
Architectural Redeployment: Reestablishing Urban Identity in the Ruins of Renewal
(2026-01-06) Rice, Colby; Not Applicable; Master of Architecture; School of Architecture; Not Applicable; Rashida Zakia; Not Applicable; Catherine Venart; Roger Mullin
The town of Portland, New Brunswick, was hollowed by urban renewal and rebranded as the North End of Saint John, triggering the neighbourhood's downfall. With a second renewal on the horizon, occurring in the ruins of past plans, this thesis asks: How might an architect participate in the successful renewal of a neighbourhood? An exploration of place and placelessness as cultural conditions suggests that intuitively valuable urban fabric is most readily produced through a bottom-up construction that maintains a legible relationship between individuals and their architecture. To foster this high-energy individual investment, a valuable sense of localized urban identity is restored by reconstructing the town's erased primary element, St. Peter's Church. The ruins are reoccupied by a new town hall, redeploying autonomy and distinction to Portland. A fragmentary architectural design method is developed to help architects achieve the human density of detail and consideration that naturally emerges from place-based dwelling.
Access status: Open Access ,
ACTIVATED BIOCHAR FOR THE REMOVAL OF PESTICIDES FROM WASTEWATER: PREPARED FROM, FLAX SHIVES, Linum usitatissimum L.
(2025-12-29) Perera, Wellaweediyage Pubudi Ama; Not Applicable; Master of Science; Faculty of Agriculture; Not Applicable; Dr.Su-Ling Brooks; Not Applicable; Dr. Sonil Nanda; Dr. Rahil Changotra; Prof. Quan Sophia He; Dr. Yulin Hu
Activated biochar, characterized by high porosity and abundant surface functional groups, has been widely applied to treat wastewater. In this study, flax shives, as an agricultural residue, were converted to activated carbon by pyrolysis followed by chemical activation to remove pesticides, i.e., 2,4-dichlorophenoxyacetic acid (2,4-D) and imidacloprid (IMI) from water. The effects of pyrolysis temperature (300-500 ℃) and residence time (1-3 h) and activation using NaOH at a biochar: NaOH weight ratio of 1:1, 1:2, 1:3 and 1:4 at 700 ℃ for 1.5 h were investigated. The activated biochar (ABC-3) obtained at a biochar: NaOH weight ratio of 1:3 exhibited a specific surface area of 2292 m2g-1 and removed 95 % of 2,4-D and 100% of IMI respectively. The co-adsorption behavior of the two pesticides was also evaluated. Kinetic and isotherm analyses showed that 2,4-D adsorption followed a pseudo-second-order kinetic model and the Freundlich isotherm model while IMI adsorption fitted well with the pseudo-first-order kinetic model and the Langmuir isotherm. Overall, flax shives-derived activated biochar demonstrated strong potential as an efficient adsorbent for pesticide removal.
Access status: Open Access ,
Bridging Expertise Gaps in Safety-Critical System Monitoring: A User-Centred Design of Adaptive Visualization and Explainable AI for Elevator Systems
(2026-01-07) Anukem, Sussan; Not Applicable; Master of Computer Science; Faculty of Computer Science; Received; n/a; Yes; Rina Wehbe; Yujie Tang; Rita Orji
The operational failure of critical infrastructure like elevators directly impacts public safety and mobility. While modern elevators generate vast amounts of sensor data, translating this data into actionable insights for diverse user groups (from maintenance engineers to building managers), remains a significant challenge in the field of Human-Computer Interaction. Existing monitoring dashboards are often hindered by a one-size-fits-all approach, reactive architectures, and interfaces that assume domain expertise, thereby creating an expertise gap that impedes effective collaboration and situational awareness. Our work is a two-phase, user-centred research project that bridges this gap through an adaptive and intelligent monitoring system. In the first phase, a controlled study (n = 20) established an empirical foundation for visualization complexity, demonstrating that effectiveness is task-dependent, not universally simple or complex. These findings directly informed the second phase: the design and evaluation of a novel system that synergistically combines an adaptive visualization interface with an AI Assistant powered by a unified reasoning engine that provides both data-grounded prognostic reasoning and natural-language explanations. A comprehensive evaluation (n = 97) demonstrated the system's effectiveness. It achieved an outstanding usability score (SUS = 98.69, SD = 5.70), provided equitable performance across technical and non-technical users, and enabled a 100% diagnostic accuracy rate for AI-assisted potential fault diagnosis. Qualitative analysis revealed the AI assistant served as an "accessibility bridge" for non-technical users and a "productivity multiplier" for experts. The primary contribution of this work is a set of six empirically validated design principles for building inclusive safety-critical monitoring systems. This research demonstrates that moving beyond static interfaces to strategically adaptive interfaces, and reframing AI as an explainable collaborative partner through transparent prognostic reasoning, provides a viable path to bridging the expertise gap for multi-level users.