Fall 2023: OU Engineering Presents Dissertation Excellence Awards
Launched in 2018, the Engineering Dissertation Award, supported by the Thomas Ira Brown Jr. Endowed Scholarship, honors Brown's contributions to the electronic control of industrial gas turbines. Commemorating his legacy, the award aims to continue his impactful work. Brown earned a bachelor's degree in electrical engineering from OU in 1950.
Fall 2023 recipients are:
Alexandra Beattie, Data Science and Analytics, Recommended by Dean Hougen
Title: "Sensitive Attribute Association Bias in Latent Factor Recommendation Algorithms: Theory and in Practice"
Abstract: This dissertation presents methods for evaluating and mitigating a relatively unexplored bias topic in recommendation systems, which we refer to as attribute association bias. Attribute association bias (AAB) can be introduced when leveraging latent factor recommendation models due to their ability to entangle model and implicit attributes into the trained latent space. This type of bias occurs when entity embeddings showcase significant levels of association with specific types of explicit or implicit entity attributes, thus having the potential to introduce representative harms for both consumer and provider stakeholders. We present a novel analysis method framework to help practitioners evaluate their latent factor recommendation models for AAB. This framework consists of three main techniques for gaining insight into sensitive AAB in the recommendation latent space: bias direction creation, bias evaluation metrics, and multi-group evaluation. Methods within our evaluation framework were inspired by techniques presented by the natural language processing research community for measuring gender bias in learned language representations. Additionally, we explore how this bias can be reinforced and produce feedback loops via retraining. Finally, we explore possible mitigation techniques for addressing said bias. Primarily, we demonstrate our methodology with two case studies that evaluate user gender association bias in latent factor recommendation. With our methods, we uncover the existence of user gender association bias and compare the various methods we propose to help guide practitioners in how best to use our techniques for their systems. In addition to exploring user gender, we experiment with measuring user age association bias as a means for evaluating non-binary AAB.
Syed Jehangir, School of Electrical and Computer Engineering, Recommended by Jorge Salazar-Cerreno and Tian-You Yu
Title: “Ultrawideband Antenna Solutions for Weather Radar Applications”
Abstract: In this dissertation, a novel ultrawideband one-size-fits-all antenna is proposed that covers 2-32 GHz of bandwidth for weather radar calibration using Unmanned Aerial Vehicles (UAVs). The proposed antenna solution holds significant importance for the radar community as it covers the commonly operated S-, C-, X-, Ku-, and K-bands. Now, a single antenna can be used for characterizing radars operating in all of these bands compared to the previous technique of using multiple narrowband antenna probes for each frequency of operation, thus saving time, labor, and cost of the system. However, not all wideband antennas can be used for this application, as the wide beamwidth of a traditional antenna can strongly interfere with the drone platform, leading to a significant degradation in the performance of the communication system. This dissertation delves into the theory, design, and feasibility of one of the kinds of a single UWB antenna or a single integrated UWB antenna system for their potential use in the characterization or calibration of weather radars and UWB communication systems.
Ana Jerdy, School of Sustainable Chemical, Biological and Materials Engineering, Recommended by Steven Crossley and Daniel Resasco
Title: “Advances in Understanding Polymer Chemical Recycling Reactions”
Abstract: This work extends the body of knowledge on plastic waste chemical recycling and upcycling reactions. The impact of common polymer additives in a polyolefin melt undergoing pyrolysis and catalytic decomposition is discussed. This is fundamental to grasp how real-world polymer products will behave when subject to chemical recycling processes, since commercial plastic products inherently contain additives. Next, it is unveiled how a common additive may deposit and alter the activity of different pore-sized catalysts. Additionally, we investigate the role that polymer structures may play in the decomposition of polymers over porous heterogeneous catalysts, and new catalyst design approaches are discussed to improve polymer-catalyst interaction. Insights from this work may help inform the industry and be one more step towards the development of optimized chemical recycling processes, which will allow for a more circular plastics economy.
Lateef Jolaoso, School of Aerospace and Mechanical Engineering, Recommended by Pejman Kazempoor and Wilson Merchan-Merchan
Title: “Integrated Protonic Ceramic Electrochemical Cell for Sustainable Energy Economy Using Water-energy Nexus Framework”
Abstract: Reliance on fossil fuels will continue for the next decades even though there are global pushes away from it to mitigate the overarching climate challenge, most especially by its highest consumers and availability. While there is a hastening global shift away from fossil fuel, integrating its assets into this technology helps limit the risk and future losses of stranded assets and reduce the cost of investment in the new technologies. Moreover, the generation of electricity from intermittent renewable sources like solar and wind has witnessed a significant surge in recent years, leading to a pressing demand for practical energy storage systems. Electrical energy storage is anticipated to play a pivotal role in the future global energy system, facilitating load-leveling operations to support the greater integration of renewable and distributed generation. Reversible electrochemical cells (RECs) offer a promising option for addressing the fossil fuel assets integration and energy storage challenges through the interconversion between electrical and chemical energy and concurrent utilizing carbon emission. In their electrolysis mode, the RECs convert electricity into durable, storable, and portable valuable chemical fuels such as syngas and methane.
Younes Saadatgharehbagh, School of Sustainable Chemical, Biological and Materials Engineering, Recommended by Reza Foudazi and Michele Galizia
Title: “Stimuli-responsive porous membranes from lyotropic liquid crystal templating”
Abstract: Lyotropic liquid crystal (LLC) templating emerges as an efficient method for synthesizing nanostructured polymers with diverse applications, particularly in molecular separation. This study concentrates on the lamellar and normal hexagonal phases of LLCs due to their ability to facilitate continuous transport paths in two and three dimensions, respectively, offering advantages for membrane applications. The research extensively investigates transcriptive and synergistic LLC templating approaches for creating stimuli-responsive membranes that adapt to external factors such as temperature and pH. The study explores the production of two-step thermoresponsive ultrafiltration membranes, showcasing adjustable pore sizes and enhanced membrane permeability. Additionally, synergistic LLC templating utilizes in-lab-synthesized polymerizable Pluronic P84 surfactant to produce H1-structured thermoresponsive ultrafiltration and nanofiltration membranes. These membranes exhibit remarkable adaptability, modulating thickness-normalized flux and pore size in response to temperature changes, demonstrating exceptional resistance to fouling and the ability to selectively separate salts based on pH conditions. The research not only expands achievable membrane pore sizes but also successfully produces stimuli-responsive H1-structured polyLLC membranes, marking a unique accomplishment in LLC templating technology.
Vinit Sheth, Stephenson School of Biomedical Engineering, Recommended by Yuchen Qiu, School of Electrical and Computer Engineering, and Stefan Wilhelm, SBME
Title: “Establishing Three-Dimensional Super-Resolution Microscopy Methods for Quantifying Intracellular Nanoparticle Distribution”
Abstract: The systemic administration of nanomedicine formulations has been described as a promising treatment option for solid tumors at both preclinical and clinical stages. However, these treatments are currently limited to improved safety over the administration of free drugs, while improvements to efficacy have been limited by a noted low accumulation of nanoparticles in cancer cells. The mechanisms for nanoparticle delivery across tumor blood vessels into the tumor microenvironment are not fully understood as a result of the physical limitations of the current standard methods of visualizing nanoparticle accumulation and intracellular transport in cancer cells. Most intracellular vesicles typically involved with the transport of nanoparticles across tumor blood vessels are sized smaller than the spatial resolution limit of light microscopy (~200 nm laterally), whereas electron microscopes, which provide sufficient lateral resolutions for visualizing these vesicles, are typically limited to thin biological samples, making it difficult to acquire three-dimensional (3D) visualizations of cells. To address these challenges, in this dissertation, quantitative 3D super-resolution light microscopy methods were applied to study the intracellular distribution of metallic and organic nanoparticle formulations in cultured cancer cells. We employed a method known as expansion microscopy, which involves embedding cell samples within swellable hydrogels to physically enlarge the sample >10X their original size for super-resolution imaging. Intracellular label-free metallic nanoparticles were visualized with light scattering imaging, while organic nanoparticles were visualized with internalized fluorescent tags. Since expansion microscopy is compatible with the labeling of intracellular features, this method enables the determination of the precise location of nanoparticles within cells, which can be used for studying intracellular nanoparticle trafficking with high spatial resolution in 3D. The successful application of this method will empower new research in nanomedicine for the development of safer and more effective treatments.
By Lorene A. Roberson, Gallogly College of Engineering
