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    Perception Stack Design and Fault-Aware Sensing for the EcoCAR Competition
    (University of Waterloo, 2026-08-17) Yousefi, Zahra
    A major challenge in the development of autonomous driving systems is ensuring that the perception layer reliably interprets and manages sensor data under real-world operating conditions. In competition and research contexts where sensors are integrated onto production vehicles, this challenge is compounded by the vehicle's existing architecture where sensors expose processed detections, rather than raw data, over proprietary CAN buses, shifting the design focus toward robust data ingestion, active health monitoring, and failure management. This thesis presents the design and implementation of a perception stack for the University of Waterloo Alternative Fuels Team competition vehicle, a 2023 Cadillac LYRIQ, developed as part of the EcoCAR Electric Vehicle Challenge. The system operates on the dSPACE AUTERA platform using RTMaps middleware and implements a modular, per-sensor pipeline comprising CAN burst detection and processing, loss-of-communication monitoring, frame decoding, sensor health checking, and data processing. A fail-safe module was designed and implemented as a custom RTMaps Python bridge component using a fault-streak counting strategy that distinguishes sustained fault conditions from transient anomalies before issuing a disable command to the planning module so that features dependent on a compromised sensor are deactivated to ensure safety. The system was validated through the XIL testing framework, progressing from synthetic CAN frame generation and baseline vehicle evaluation data replay through hardware-in-the-loop testing on the AUTERA, demonstrating that a modular, fault-aware perception pipeline can be designed and implemented on a production vehicle platform under competition constraints.
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    Development of Hydrogel/Aluminum-based Adsorbent Beads and Membranes for Lithium Extraction from Brines
    (University of Waterloo, 2026-08-17) Fan, Chaogang
    Driven by the rapidly expanding market for lithium-ion batteries, the global demand for lithium is projected to surpass 2.4 million metric tons of lithium carbonate equivalent (LCE) in 2030. Lithium extraction from salt-lake brine, which contains 70% of global reserves, is transitioning from inefficient solar evaporation to Direct Lithium Extraction (DLE) technologies. Among DLE methods, adsorption stands out for its superior selectivity and cost-effectiveness in low-grade brines. Nevertheless, the industrial deployment of powder adsorbents is hindered by operational challenges, such as high pressure drop, high material loss, and poor flowability. While current solutions involve immobilizing powders within polymeric binders, this approach introduces new problems: the matrix often causes pore occlusion at active sites and increases mass transfer resistance, thereby compromising lithium (Li⁺) adsorption capacity and kinetics. In this work, a series of hydrogel/aluminum-based adsorbent composite beads and membranes was developed to minimize additional mass transfer resistance. These composites exhibited high Li⁺ extraction capacity, stability, and rapid diffusion kinetics in both batch adsorption and membrane extraction systems. Initially, a lithium aluminum layered double hydroxide adsorbent (LiAl) was synthesized via the coprecipitation of aluminum chloride and lithium chloride in an alkaline solution, achieving a high and stable adsorption capacity of approximately 7.3 mg/g. Notably, aging conditions during fabrication and wet storage were identified as critical factors for maintaining high Li⁺ adsorption capacity, as they preserved the crystallinity of LiAl and reduced particle aggregation. Furthermore, LiAl demonstrated rapid desorption/adsorption kinetics, which were fitted with pseudo-first-order (PFO) and pseudo-second-order (PSO) models. Next, LiAl was granulated using porous and hydrophilic chitosan (CS) as a binder, yielding composite beads with rapid Li⁺ adsorption kinetics. By adjusting bead composition (LiAl, CS, and porogen) and operational parameters (e.g., water-to-solid ratio), a Li⁺ adsorption capacity of 4.4 mg/g was achieved. The adsorption equilibrium and kinetics were well-described by the Langmuir isotherm and the PFO model, respectively, suggesting a monolayer adsorption on relatively homogeneous active sites. Notably, a film-pore diffusion model was applied to elucidate mass transfer mechanisms. A calculated Biot number of approximately 16 at an agitation speed of 120 rpm indicated that intra-particle diffusion was the dominant step. The beads achieved near-equilibrium within approximately 2 h, yielding a high pore diffusion coefficient (Dₚ) of 2.15 × 10⁻¹⁰ m²/s. Furthermore, the composite beads exhibited robust cyclic stability (maintaining 4.4 mg/g after 12 cycles) and selectivity towards Li⁺. This approach demonstrated that the application of a hydrogel binder was effective in maintaining rapid Li⁺ diffusion kinetics in the granulated LiAl beads. Sodium alginate was investigated as an alternative binder to chitosan to enhance Li⁺ adsorption capacity, leveraging its milder gelation process to preserve the LiAl structure. The alginate/LiAl beads exhibited a high adsorption capacity of approximately 7.5 mg/g within a short adsorption time of 2 h over 10 adsorption-desorption cycles. A film-pore diffusion model based on Langmuir adsorption isotherm analysis was applied to elucidate the adsorption kinetics, confirming that Li⁺ uptake was primarily governed by pore-volume diffusion. The beads exhibited a high Dₚ of approximately 1.96 × 10⁻¹⁰ m²/s, indicating the alginate binder imposed minimal resistance to ion transport. Furthermore, the structural instability of the alginate beads caused by the leaching of cross-linking Ca²⁺ was mitigated by the presence of Ca²⁺ ions in the feed solution or by chemical cross-linking with hydrophilic and flexible poly (ethylene glycol) diamine. The composite beads also demonstrated high selectivity for Li⁺ over Mg²⁺, Na⁺, and Ca²⁺ in the simulated brine. To further exploit the rapid kinetics of the hydrogel/LiAl composite and enable simultaneous adsorption and desorption, this study extended its application from batch adsorption to membrane extraction (ME) systems. ME, which combines an organic extractant with a partitioning membrane, is an efficient and sustainable strategy for recovering Li⁺ from salt-lake brines. However, the development of membranes possessing both a high Li⁺ flux and solvent resistance remains a challenge. In this work, a porous chitosan membrane embedded with LiAl was used as a partitioning barrier in the membrane contactor for Li⁺ extraction, with tributyl phosphate (TBP)/kerosene being the extractant. A high Li⁺ flux of 3.63 × 10⁻⁸ mol/(cm² s) was achieved at a feed Li⁺ concentration of 0.2 mol/L. The impacts of individual resistance components in the membrane extraction process on overall mass transfer were analyzed using the resistance-in-series model, and the external mass transfer resistances (liquid boundary layer near the membrane surface and interfacial Li⁺-extractant complexation) were found to be significant for a 19 μm CS/LiAl membrane. The CS/LiAl membrane facilitates preferential Li⁺ transport, while the organic extractant primarily governs the overall Li⁺ selectivity of the extraction process. The versatility of this membrane was further demonstrated using a β-diketone-based organic extractant, which maintained a high Li⁺ flux of more than 3.50 × 10⁻⁸ mol cm⁻² s⁻¹ for 19 days. This study presents an efficient strategy to significantly enhance lithium flux in membrane extraction systems by leveraging the rapid mass transfer in hydrogel/LiAl membranes.
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    Reliability-Based Fracture Toughness Requirements for Steel Highway and Pedestrian Bridges
    (University of Waterloo, 2026-08-17) Ying, Thomas
    Although the brittle fracture toughness requirements currently prescribed for Canadian steel highway bridges in CSA S6 appear to be meeting the needs of designers and users, these provisions exhibit shortcomings in terms of their lack of a probabilistic basis, in contrast with other failure modes, and their lack of flexibility, relative to international design provisions in Europe and the United States. A probabilistic basis of these provisions has only recently been established. The results of this effort highlighted a potential lack of conservatism for high yield strength plates and offered the potential to develop new design tools for explicitly considering important factors known to affect brittle fracture risk, such as plate thickness or demand-to-capacity ratio (DCR). At the same time, CSA S7—a new guideline recently developed for the design of pedestrian bridges—only considers a reduced strain rate in the relaxation of toughness requirements for Canadian steel pedestrian bridges when compared to those for highway bridges, and neglects the possible effects of differences in usage patterns, material properties, common weld details, susceptibility to fatigue, and typical governing limit state. In order to define improved brittle fracture provisions for highway and pedestrian bridges, address industry concerns about the scarcity of sufficiently tough hollow structural sections (HSS), and propose new design tool formats for selecting Charpy V-notch (CVN) test requirements, this project set out to describe a methodology for establishing reliability-informed fracture toughness requirements using Monte Carlo simulation, a fracture toughness master curve, finite element analysis (FEA), and new and existing highway traffic and pedestrian probabilistic live load models. The presented work includes improvements to a previously-developed probabilistic assessment tool and the verification of existing magnification factor solutions for common weld details, including transverse attachments and butt welds. Additionally, new magnification factors are determined for the K-joints in typical pedestrian bridges using the FEA software ABAQUS. A pedestrian live load model is defined based on similar concepts used to prescribe live loads in buildings. Even when making conservative assumptions about parameters, this model is found to reflect the low probability of the pedestrian live load exceeding the nominal load, let alone the factored design load. For a range of plate thicknesses, climates, target reliability indices, weld details, and live load models, simulations of different combinations of yield strength, DCR, and CVN test temperature are conducted using the assessment tool. Results are fitted to two-degree surfaces of test temperature as a function of yield strength and DCR. Three design tool formats are created using the results: 1) surface coefficient lookup tables; 2) contour plots; and 3) augmented design tables of CVN test requirements. The toughness requirements for highway bridges are found to be stricter as plate thickness, yield strength, and DCR increase. For most weld details, except for the most severe longitudinal attachment, it is shown that toughness requirements for pedestrian bridges can almost be neglected, particularly when considering the yield strengths and DCRs typical of pedestrian bridges. To support these conclusions, future research could focus on improving existing highway live load models with recent gross vehicle weight data and continue to establish realistic parameters for the developed pedestrian live load model. Additional work on finite element models would improve understanding of fracture toughness requirements for K-joints and other weld details fabricated with HSS members. Lastly, the integration of a fatigue crack growth model could be used to justify the use of lower target reliability indices by explicitly considering the effects of inspection and fatigue crack growth, allowing engineers to take advantage of the relaxation of requirements and higher calibrated crack depth demonstrated through the sensitivity studies in this project.
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    Biochemical Characterization of Heterogeneous Nuclear Ribonucleoprotein A2 Inclusion Body Structure and Stability
    (University of Waterloo, 2026-08-17) Rodriguez Cruz, Pedro
    Inclusion bodies (IBs) are heterogeneous protein aggregates formed during recombinant protein expression in bacteria. IBs are advantageous for biotechnical applications as well as for research targeting the underlying mechanisms of protein aggregation in cells. Aberrant protein aggregation is central to various diseases, but the etiology and mechanisms remain poorly resolved in general. It is of great interest then to biochemically characterize disease-related aggregates in a tractable and controllable system. IBs are therefore an attractive model for examining how the cellular environment shapes aggregation, including the determinants relevant to pathological aggregation. The heterogeneous nuclear ribonucleoprotein A2 (hnRNPA2) is found in various disease states, having aggregates discovered in postmortem patient tissue samples. hnRNPA2 is a ubiquitously expressed nucleic acid housekeeping protein in human cells, containing both structured domains and a prominent disordered prion-like domain. In particular, the intrinsically disordered low complexity domain (also referred to as the prion-like domain) of hnRNPA2 is the site of several point mutations that are associated with disease. For example, the D290V mutation is thought to aberrantly drive the naturally reversible self association function of hnRNPA2 to become irreversible, while the P298L mutation has been proposed to extend an amyloid-prone region by substitution of a key proline with a flexible hydrophobic residue. D290V has been associated with various diseases including amyotrophic lateral sclerosis, frontotemporal dementia, and other neurodegenerative diseases. P298L has been reported only in Paget’s disease of bone. Using a battery of complementary biochemical experiments, the results in this thesis demonstrate that these mutations promote a more stable inclusion body. Specifically, these experiments include quenched hydrogen-deuterium exchange NMR, mass spectrometry, Fourier transform infrared spectroscopy, urea solubilization assays, and limited proteolysis measured by mass spectrometry. Notably, wild-type IB formation appears to depend on the N-terminal affinity tag, whereas both disease variants aggregate independently of it — a result that qualifies direct wild-type-to-mutant comparison and has implications for the use of tagged constructs in aggregation studies. Moreover, D290V gives rise to a generally more stable IB while the effects of P298L present as more subtle and localized in its effects. In conclusion, a wide range of experiments were conducted to characterize IB formation in depth to examine wild-type and disease variant aggregation in a cellular context. Ideally, the work conducted here will help with disease research efforts.
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    Quantum Light Sources from Solid-State Emitters
    (University of Waterloo, 2026-08-17) Low, Zuo Kai Nicholas
    Quantum light generated by solid-state emitters has become a leading resource for photonic quantum technologies, combining deterministic emission with scalable on-chip integration. Practical deployment of these light sources requires characterising the light they produce, optically addressing them individually and ensuring light can be extracted efficiently from the solid-state host. In this thesis, we first study how the quantum nature of light can be characterised via its photon statistics. We then examine how to speed these measurements up, a necessity for the scalable characterisation of many emitters. We find that the use of multiplexed single-photon detectors offers a straightforward route to faster characterisation of quantum light sources via photon correlation measurements, while simultaneously providing additional information about the statistics of emitted photons. Next, we explore how to optically address individual emitters via confocal microscopy at cryogenic temperatures. We report the development of such a setup, demonstrating both widefield imaging and photoluminescence raster imaging of individual emitters. Finally, we engineer the diamond host to enhance photon extraction from embedded emitters, extending a previously reported fabrication process for photonic nanojet structures to (111)-oriented diamond. We confirm high-fidelity pattern transfer using scanning electron microscopy and profilometry, establishing that the adapted process is compatible with this orientation. Together, these results contribute to the characterisation, addressing and engineering capabilities required for the practical deployment of solid-state quantum emitters in quantum technologies.