Lakehead University Knowledge Commons

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Investigating the phase behavior of alcohol/water/salt mixtures at ambient conditions (alcohol: ethanol and isopropanol; salt: Na2CO3 and K2CO3)
(2026) Thenmalai Ihimamudeen, Mohamed Rayyan; Ramos-Pallares, Francisco; Rakshit, Sudip; Kang, Kang
Alcohol has emerged as a promising alternative to fossil fuels in transportation due to lower CO2 emissions, compatibility with existing engine technologies and that can be produced from renewable resources. However, the separation of alcohol from water using conventional distillation is energy and carbon intensive. Salting-out, a liquid/liquid-based separation, has the potential to reduce the carbon footprint and cost associated with conventional distillation because it can be carried out at lower temperatures. Adding some salt to a mixture of alcohol and water reduces the solubility of the alcohol triggering a liquid/liquid (LL) phase split with one of the phases rich in alcohol. Therefore, understanding the phase behavior of alcohol/water/salt mixtures is essential for developing the salting-out separation technology. The objectives of this study were to map the phase behaviour of mixtures containing alcohol water and salt at ambient conditions. The alcohols tested were ethanol and isopropanol; and, the salts tested were sodium carbonate (Na2CO3) and potassium carbonate (K2CO3). The following phase boundaries were experimentally mapped in this study: liquid↔liquid-liquid (L↔LL) and liquid-liquid↔liquid-liquid-solid (LL↔LLS). The compositions of the two liquids phases at equilibrium within the liquid-liquid region were experimentally measured. The thermodynamic reliability of the collected experimental data (boundaries and liquid-liquid phase compositions) was assessed using an in-house graphical method. Note: all the data collected in this study were tested for thermodynamic reliability in order to ensure that all of it corresponds to actual thermodynamic equilibrium data. A simple modeling approach was developed for the calculation of the L↔LL and the liquid-liquid tie-lines. This model is based on empirical correlations fitted to the partitioning coefficients calculated from the experimental equilibrium compositions. This study is therefore aimed at producing reproducible, reliable and thermodynamically consistent data that can facilitate the modelling of the aforementioned systems for practical engineering applications.
Policies, politics and people: US and Canadian immigration policies from 1960 to the present
(2025) Hossein Pour, Azam; Agbo, Seth; Hoechsmann, Michael
My motivation for writing a thesis on Canadian and US immigration policies stems from my experience as an immigrant from Iran, navigating the Canadian immigration landscape and encountering several effects of Canadian immigration policies that could help new immigrants make informed migration decisions. This thesis critically investigates the evolution of immigration policies in the United States and Canada from the 1960s to the present, with a particular emphasis on their economic, social, and cultural dimensions. It seeks to illuminate how such policies simultaneously reflect and construct national narratives of belonging. In the United States, immigration has been alternately embraced and curtailed by shifting economic imperatives and the rise of populist discourses. In contrast, Canada has employed immigration as a strategic mechanism to attract economically desirable migrants, although tensions persist between its humanitarian commitments and neoliberal policy frameworks. Through a comparative analysis, this study demonstrates that these dynamics profoundly shape not only national trajectories but also the lived experiences of immigrants—among them the author, a diasporic Iranian-Canadian educator. Employing an autoethnographic methodology, the research foregrounds the mediating role of educators and educational institutions in negotiating the boundaries between inclusion and exclusion. As such, it contributes meaningfully to scholarship within faculties of education and to broader conversations on identity and belonging in multicultural societies. The findings yield critical insights for policymakers, teacher educators, and scholars concerned with the intersections of migration, education, and social integration.
An experimental approach to sand particle cloud dispersion under stagnant and controlled turbulence: new insights for water engineering applications
(2026) Sabershahraki, Maliheh; Azimi, Amir; Mohamedelhassan, Eltayeb; Liao, Baoqiang; Zhang, Wenming
This thesis presents a comprehensive experimental investigation into the dispersion and evolution of sand particle clouds in water, emphasizing the development of a novel programmable facility capable of generating controlled turbulent background flow. A custom-built design including forty-pumps was designed to generate reproducible, near-zero- mean turbulence in a confined tank, where flow intensity could be adjusted through programmed activation sequences and the use of mesh screens with different openings. The facility enabled systematic variation of turbulence intensity from approximately 2.5% under weak forcing to 9.4% under strong forcing, allowing discrete and repeatable classification of weak, medium, and strong background turbulence regimes. This range overlaps with turbulence intensities reported in energetic natural environments, where field measurements in coastal and tidal flows indicate strong turbulence levels on the order of 9-12%. The designed system provides an unprecedented level of control and repeatability, enabling systematic exploration of particle-turbulence interactions under well-defined conditions. A MATLAB-based image analysis framework was established to extract quantitative parameters from high-contrast recordings. The workflow included background subtraction, binarization, inversion, air-bubble removal, boundary detection, and concentration tracking using the normalized red channel (R/255), where R, G, and B denote the red, green, and blue pixel intensities and R = G = B in this setup. In all experiments, sand particle clouds were generated by releasing dry sand through a vertical nozzle into a confined water-filled tank, forming negatively buoyant particle clouds without premixing with water. The tank geometry was fully confined, allowing controlled background turbulence to be imposed using the programmable pump array. Particle size was uniform within each test and characterized by the Stokes number, with multiple particle sizes examined systematically across the study. From the processed frames, penetration length, frontal velocity, lateral width, projected area, and an image based entrainment coefficient were determined. The effects of background turbulence intensity, particle size, and release geometry on particle cloud evolution were examined. Controlled turbulence was found to interrupt deep descent, enhance lateral spreading, accelerate breakup, and increase entrainment compared to stagnant ambient. Fine particles responded strongly to turbulent fluctuations, forming diffuse and laterally extended clouds, whereas coarse particles retained compact symmetry and settled quickly. Additional experiments were conducted in an immiscible oil–water system in which sand particles were released through the oil layer into the underlying water phase, allowing the effects of interfacial resistance and release configuration on sand particle cloud formation to be examined. Complementary tests in stagnant water revealed that higher release energy and aspect ratio promote early penetration and wider cloud development. Together, these studies established a unified framework for understanding the coupled effects of turbulence, geometry, and particle size on sand cloud evolution. The novel turbulence generation system and analysis methodology provide quantitative benchmarks for future investigations and offer insights applicable to sediment transport, dredging, wastewater discharge, and other particle-laden flow processes where controlled mixing and dispersion are essential. Keywords: Controlled background turbulence; Image-based analysis; Acoustic Doppler Velocimetry (ADV); Sand particle clouds
Towards practical and cybersecurity-aware Dynamic State Estimation in power systems
(2026) Riahinia, Shahin; Ameli, Amir; Yassine, Abdulsalam; Karimipour, Hadis; Uddin, Mohammad Nasir; Dekka, Apparao
Dynamic State Estimation (DSE), empowered by the growing deployment of Phasor Measurement Units (PMUs) within Wide-Area Measurement Systems (WAMS), has become essential for power system monitoring, control, and real-time contingency analysis. However, the effectiveness of DSE critically depends on accurate system data, which might be impacted by both cyber-attacks and real-time network variations. This thesis addresses these challenges through three interconnected research contributions. First, recognizing the vulnerability of WAMS and PMUs to False Data Injection Attacks (FDIAs), a cybersecurity-aware DSE is developed to detect and mitigate such cyber threats. This method augments the Extended Kalman Filter (EKF) used in DSE with a Machine-Learning-based Penalized Weighted Least Squares (MLPWLS) approach, optimizing measurement weights based on their vulnerability. By excluding compromised measurements, the proposed solution significantly enhances the resilience and accuracy of DSE under various cyber-attack scenarios, as validated on IEEE 14-bus and 39-bus test systems. Second, addressing the practical limitations of traditional DSE methods, this research introduces an adaptive Y-bus matrix estimation approach. A Recursive Least Squares (RLS) estimator with a Gauss-Newton Variable Forgetting Factor (GN-VFF) is developed, eliminating the need for continuous Y-bus input. By leveraging inverse power flow equations, this estimator dynamically adjusts to system changes, thus enhancing the practicality, responsiveness, and overall accuracy of DSE implementations. Finally, building upon these advancements, this dissertation presents a comprehensive real-time framework for complete Y-bus estimation using limited PMU data. This innovative two-stage architecture initially estimates a reduced Y-bus matrix through a recursive algorithm integrating a Vectorized Variable Forgetting Factor (VVFF) within the RLS framework. Subsequently, the complete Y-bus matrix is reconstructed via an overdetermined least-squares optimization based on Kron-reduction. Integrated within a simultaneous dynamic and algebraic state estimation (SDASE) framework, this approach demonstrates significant accuracy, convergence, and scalability improvements, bridging static modeling assumptions and dynamic operational realities. Together, these contributions provide a practical, secure, and dynamically adaptive framework for state estimation in a multi-machine power systems, significantly advancing real-time grid intelligence and reliability under both cyber threats and evolving operating conditions.
Total oxidation of naphthenic acids by catalytic ozonation
(2026) Babazadeh, Mohammad; Liao, Baoqiang; Rezaei, Ebrahim; Azimi, Amir; Kang, Kang
This study investigated the mineralization of a model naphthenic acid compound, 4-methyl-1-cyclohexane carboxylic acid (4MCH), by catalytic ozonation. A catalyst screening was conducted using Cu, Ce, and Mn dispersed on γ-Al2O3, TiO2, ZrO2, and MgO to formulate an active catalyst for total oxidation of 4MCH. Cu/MgO (1 and 5 wt%) catalysts had the highest total organic carbon (TOC) removal. The catalysts maintained their TOC removal over five reusability cycles. The effect of various operating parameters, such as the pH of the reaction media, inlet gas phase ozone concentration, and type of buffer, was studied on the TOC removal of the Cu/MgO catalysts. To improve the activity of the Cu/MgO catalysts, novel copper-magnesium phosphate catalysts (CuxPyMg) were synthesized with different molar ratios of Cu to Mg (i.e., x) and P to Mg (i.e., y). The crystalline structure of the CuxPyMg catalysts was made of Mg(OH)2, Mg3(PO4)2·zH2O (z = 5 and 8), and MgNH4PO4·H2O. Cu atoms partially substituted Mg atoms and formed bonds with phosphorus atoms via lattice oxygen atoms. The Cu0.01P0.1Mg catalyst had the highest TOC removal with the lowest leaching of Cu and P. The P=O functional group of the Cu0.01P0.1Mg catalyst, combined with the atomic dispersion of Cu, resulted in 12 times faster TOC removal rates when compared to those of the Cu/Mg catalyst. A probe-based kinetic study was conducted to quantify the contributions of various reactive oxygen species involved in the oxidation of 4MCH. 57% of 4MCH was oxidized by hydroxyl radicals, while the contributions of ozone and superoxide radicals were 33% and 10%, respectively. Singlet oxygen had no reactivity with 4MCH. The by-products of the oxidation of 4MCH were identified, and a reaction network was proposed for the oxidation of the molecule. It was proposed that the early stages of 4MCH oxidation involved the formation of oxygenated and hydroxylated intermediates, which ultimately decomposed into carbon dioxide and water. In conclusion, this research established that Cu/MgO and CuxPyMg catalysts were suitable catalysts for total oxidation of recalcitrant naphthenic acids.