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Investigating the impact of CO₂ on seismic wave attenuation
Get PDFCarbon capture and storage (CCS) is an important process to reduce atmospheric CO₂ levels. Injection of CO₂ into subsurface units such as depleted hydrocarbon reservoirs or saline aquifers serves as the primary storage method in these CCS efforts. Time-lapse seismic data is required to track CO₂ plume migration and ensure containment. The waves in these seismic surveys experience attenuation while propagating through CO₂-saturated reservoirs, which is attributed to wave-induced fluid flow (WIFF) and wave-induced gas exsolution-dissolution (WIGED). Neglecting the impacts of this attenuation can cause inaccurate interpretations of the data used to monitor CO₂-injection sites. This study seeks to quantify the attenuation impacts caused by the WIGED mechanism, which has been neglected in many previous works. To investigate the WIGED mechanism, an experiment was conducted on a fluid mixture expected to represent the contents of a CO₂ plume. The results of this experiment supported the attenuation value assigned to rock units containing injected CO₂. A geologic model representing a CO₂-injection site in a saline aquifer capped by a structural trap was developed. Simulations were run on this geologic model using seismic modeling with finite differences (SOFI 2D). Viscoelastic simulations accounting for attenuation were compared to elastic simulations where no attenuation occurred. Cross-correlation analysis between elastic and viscoelastic datasets targeted reflections impacted by attenuation. Results show that waves traveling through the CO₂-saturated region exhibit reduced amplitudes and phase shifts relative to elastic datasets. This analysis highlights the need to incorporate attenuation in seismic-monitoring workflows to improve the accuracy of CO₂ plume storage assessments.Earth and Planetary Science
My geography of islands
Get PDFThere came a moment when the ground took on a newfound significance. At first I didn’t notice it amidst the mourning, and then it became all-consuming, an attempt to fill in the absence. Sometimes Island is ground in relation to water in relation to control. This site became my studio over the last two years.Studio Ar
Building material reuse in Austin’s residential sector : barriers, opportunities, and implementation strategies
Get PDFThis research investigates building material reuse in Austin's residential construction sector, addressing the disconnect between sustainability goals and implementation practices. The construction industry generates significant environmental impacts through resource consumption and waste production, with the United States alone producing 600 million tons of construction waste annually. Building material reuse presents a critical opportunity to preserve embodied carbon, reduce landfill burden, and create economic opportunities. Using a mixed-methods approach combining demolition permit analysis, case studies, green building certification trends, and policy assessment, this study identifies key barriers and enablers to material reuse adoption. Findings reveal approximately 40% of single-family residential demolitions involve pre-1950s structures containing high-value reusable materials, clustered in central Austin neighborhoods but largely uncaptured by current regulatory frameworks. Successful implementation currently depends on highly motivated stakeholders navigating complex challenges in sourcing, storage, and processing. The research identifies infrastructure gaps that could be inhibiting broader adoption, including limited information systems, inadequate storage facilities, and fragmented local reuse marketplace. Austin Energy Green Building certified projects incorporating material reuse achieve significantly higher average ratings (4.46 vs. 2.19 stars) but represent only a very small fraction of certified buildings, demonstrating material reuse remains a specialized practice rather than a mainstream approach to achieve sustainability benchmarks. Research demonstrates that regulatory frameworks are essential for achieving environmental goals in the construction sector. Despite Austin's ambitious climate targets, including 40% embodied carbon reduction by 2030, current policies overlook residential demolition, creating a significant regulatory blind spot in both embodied carbon accounting and waste management. This study provides recommendations organized into short-term (information systems, education), medium-term (deconstruction requirements, processing facilities), and long-term (building code integration, systemic changes) implementation strategies. By addressing these barriers strategically, Austin can capture valuable material flows, reduce embodied carbon, create workforce opportunities, and align construction practices with climate equity goals while establishing effective pathways for material circularity in residential construction.Architectur
Evaluating the feasibility of heat pump water heater adoption in Texas through incentives and time-of-use electricity pricing
Get PDFThis study investigates the financial feasibility of heat pump water heater (HPWH) adoption across Texas residential buildings, utilizing building energy modeling, financial analysis, and an optimization algorithm under different policy and electricity pricing scenarios. The analysis leverages NREL’s ResStock tool in combination with OpenStudio-HPXML simulations to model building energy consumption and applies a Bayesian Optimization algorithm to explore load-shifting potential under Time-of-Use (ToU) electricity rates. The baseline scenario reveals a significant barrier to HPWH adoption, with 98.7% of homes experiencing positive utility bill savings but only 22.9% achieving a positive net present value (NPV) due to high upfront costs. Federal incentives, such as the Inflation Reduction Act tax credits, improve cost-effectiveness, nearly doubling the proportion of homes achieving positive NPVs to 45.4%. The most favorable outcomes emerge from combining federal incentives with ToU optimization, which increases the percentage of homes with positive NPVs to 59.6%. The analysis also finds that optimized HPWH schedules could help reduce peak demand, potentially contributing to grid reliability and offering system-wide benefits. The cost-effectiveness of HPWH adoption is significantly influenced by home characteristics, as revealed through a mutual information analysis. The analysis identified the reference water heater type and the number of occupants as the most impactful factors on cost-effectiveness. This thesis emphasizes the need for targeted-policy approaches to overcome financial barriers and achieve widespread HPWH adoption.Civil, Architectural, and Environmental Engineerin
LightMARL : smart swarm coordination in urban spaces
Get PDFMulti-Agent Reinforcement Learning (MARL) systems generally require substantial computational resources and high-bandwidth communication, which restricts their deployment to centralized cloud infrastructures. This thesis introduces LightMARL, an optimization framework that facilitates effective multi-agent coordination on resource-constrained edge devices while ensuring coordination quality and real-time performance. LightMARL tackles three primary challenges: computational efficiency, communication overhead, and scalability. To improve computation, the framework utilizes neural network quantization, structured pruning, and knowledge distillation tailored for multi-agent policy optimization (MAPPO). These methods decrease model size and computational demands while maintaining essential coordination behaviors. To enhance communication efficiency, vector quantization combined with delta compression, attention-driven selective information sharing, and predictive protocols minimize bandwidth usage and latency. The framework is structured as a modular Python system incorporating C++ components, supporting deployment on Nvidia Jetson platforms. Experimental validation in simulated environments, including drone swarms, vehicle platooning, and sensor networks, demonstrates the framework’s effectiveness. This study illustrates that complex multi-agent coordination is possible on edge devices, enabling new applications in autonomous functionality.Computer Scienc
Material shelter
Get PDFDriving west, away from the junkyard of my childhood, I have become an intentional wanderer uncovering narratives and rhythms through deep listening, care, and play. I translate these skills into an artistic method that responds to a broader view of the present that recognizes precarity as the defining condition of our time.¹ My practice is influenced by authors like Robin Wall Kimmerer, Jenny Odell, and Anna Lowenhaupt Tsing, who each, in their own deeply considered way, highlight the necessity of skills from beyond institutional frameworks to respond to the predicament of the Anthropocene. I am motivated by the ability of artists to act as guides, witnesses, and innovators in times of ecological and economic ruin. Using socially oriented, assemblage-based storytelling, I position art making as a wellspring of hope, catharsis, and survival.Studio Ar
The Jordanian tightrope : King Abdullah II’s balancing act in the monarchy’s response to October 7th
Get PDFDuring the twentieth century, monarchies across the Middle East were overthrown, giving way to new governments that faced public unrest and foreign intervention, continuing into the twenty-first century. However, while these tumultuous governmental changes occurred, one state remained consistent: the reign of the Hashemite Family in the Kingdom of Jordan. Due to its geopolitical location, scarce natural resources, and hostile Islamist forces, the kingdom relies heavily on U.S. aid while addressing domestic instability. The eruption of the Israel-Hamas War on 7 October 2023 heightened these challenges for King Abdullah II. This research argues that Jordan’s monarchical stability depends on the King’s ability to navigate competing interests. Domestically, the monarchy employs media to portray itself as the “saviors” of Palestine by solidifying consent of the people through performative discourses. Internationally, Jordan’s policy decisions align with the expectations of its primary donors, particularly the United States. Focusing on the January 2024 Israeli allegations against UNRWA and the August 2023 siege of Jenin, this study uses critical discourse analysis of the Jordanian media sources Al-Rai and Al-Mamlaka to examine how these events reflect the monarchy’s balancing act. It highlights how media narratives and policy decisions address domestic and international pressures, ensuring the monarchy’s continued survival amidst regional and global complexities.Middle Eastern StudiesGlobal Policy Studie
Powering the narrative : how the Russian state frames energy security
Get PDFThis thesis explores how the Russian Federation conceptualizes energy security by analyzing the discourse of the Russian state via five influential state actors: the President’s Office, the Ministry of Energy, the Ministry of Economic Development, Gazprom, and Rosneft. This study fills a critical gap in energy literature by departing from traditional approaches that focus primarily on democratic, energy-importing nations and investigating the rhetorical strategies of an authoritarian, energy-exporting state. Employing a discourse and content analysis framework, this study analyzes 163 official documents published between 2019 and 2022, coded using NVivo 15 software. The analysis is grounded in four theoretical frames––securitization, economic efficiency, technological advancement and innovation, and imperialism––developed through a review of existing literature on energy policy, security studies, and authoritarian state behavior.
Findings reveal that the Russian state overwhelmingly frames energy security through the lens of economic efficiency, regardless of the institution. This economic emphasis persists even when energy discourse overlaps with security, technological, or imperial narratives. Technological advancement and innovation emerged as the second most prevalent frame, often interlinked with economic goals. The imperialism and securitization frames were used sparingly and were often in tandem with economic or geopolitical rhetoric.
The thesis concludes that for the Russian state, energy is not primarily framed as a matter of ideology or military posturing, but of strategic economic management. This insight holds significant implications for international policy: actors engaging with Russia on energy matters should prioritize economic levers such as trade, tariffs, and market influence. Western powers, in particular, must strengthen their control over global markets to effectively influence Russian energy policy and limit its pivot toward alternative partners like China. In a geopolitical climate defined by energy transitions and regional conflicts, understanding the Russian state’s framing of energy security is crucial for effective diplomacy and strategic economic planning.Slavic and Eurasian Studie
From molecular damage to interfacial fracture : multiscale insights into the mechanics of pressure-sensitive adhesives
No full textSoft and pressure-sensitive adhesives (PSAs) are essential to emerging technologies in flexible electronics, biomedical devices, and packaging. Despite their widespread use, the molecular mechanisms governing their interfacial and bulk fracture behavior remain poorly understood, particularly under complex deformation conditions. This work integrates mechanochemistry, controlled polymerizations, and digital image correlation, among other techniques, to elucidate the interplay between viscoelasticity, molecular damage, and interfacial fracture propagation mechanics across multiple length and time scales. By employing fluorogenic mechanophore probes as molecular damage probes in soft adhesives, molecular damage was quantified during T-peeling under varying viscoelastic conditions. We demonstrate that damage occurs during debonding and follows a non-monotonic dependence on the Weissenberg number (W[subscript i]). At fast debonding rates, molecular damage is nearly undetectable despite high adherence energies, revealing distinct regimes of chain breakage, frictional dissipation, and network stiffening. Leveraging the same mechanochemical approach, we uncover a previously unreported micro-stick-slip instability during 90° peeling, driven by a decrease in local energy release rate rather than changes in macroscopic dissipation. This micro-instability reveals a coupling between viscoelastic stress transfer and molecular-scale damage dynamics. Controlled polymerizations, specifically reversible addition fragmentation chain transfer (RAFT), were used to investigate how compositional drift and associative interactions influence PSA properties. Tack was found to be highly sensitive to compositional variations due to the localization of physical crosslinks and limited stress dissipation. To probe bulk long-term PSA failure, digital image correlation was used to map stress and strain fields during static-load lap shear testing. We show that crosslink density controls stress localization and the resulting failure mode - either interfacial or cohesive. A linearly viscoelastic shear lag model captures the observed stress delocalization due to PSA creep. Together, these findings reveal fundamental insights into how molecular-level physics and damage processes govern interfacial fracture mechanics, providing design principles for tuning energy dissipation, damage, and adhesion in soft polymer networks. This work advances both the fundamental understanding of fracture in soft materials and the development of high-performance adhesives.Chemical Engineerin
Development and evaluation of a machine learning-enhanced drift-flux model in molten-salt bubbly flow
No full textAs a part of an effort to increase nuclear power by 2050, molten salt reactors (MSRs) are recognized as a strong candidate for the next generation of advanced nuclear technologies. Compared to traditional light water reactors (LWRs), MSRs offer enhanced safety, efficiency, economy, and sustainability. However, the unique thermo-physical properties of molten salt and fuel present significant challenges for modeling and reactor design. Observations from the Molten-Salt Reactor Experiment (MSRE) at Oak Ridge National Laboratory revealed that helium gas, introduced to remove fission product poisons, became entrained in the fuel-salt mixture. This led to an increase in void fraction and compressibility effects in the fuel density inducing pressure-dependent reactivity, which is correlated with reactor power. Although these effects were manageable at low power, their behavior in high-power MSRs remains uncertain, underscoring the need to accurately predict void fraction distributions in salt-gas mixtures. The drift-flux model has been extensively used in system thermal-hydraulic codes to predict two-phase flow dynamics, including void fraction, but they rely on constitutive terms that are typically estimated using empirical correlations. These correlations are generally developed for vertical upward pipe flows in water-air, air-steam, and steam-water systems, limiting their applicability to alternative fluids, flow orientations, and unique geometry. To overcome these limitations, a data-driven machine learning (ML) approach was used to develop a generalizable model for the distribution parameter and mean local drift velocity term using high-fidelity computational fluid dynamics (CFD) data. The CFD simulations were performed using the twoPhaseEulerFoam and multiphaseEulerFoam solver in OpenFOAM to model dispersed argon gas flow in HITEC molten salt under various pipe orientations and operating conditions. Temporal and spatial averaging was performed on the resulting three-dimensional data to extract properly weighted one-dimensional quantities suitable for ML training and code-to-code comparison. A neural network was trained and optimized to predict the distribution parameter and the mean local drift velocity from selected input features, and its performance was evaluated on training and testing (unseen) datasets with most predictions falling within one standard deviation (±1σ) from the variance in the stochastic fluctuations. Using the same datasets, the optimized ML models were then tested in the System Thermal-Hydraulics (SyTH) module, which uses a modified one-dimensional drift-flux model. Results presented in a parity plot show that the SyTH output for gas and drift velocities agrees with high-fidelity CFD data within ±20%. A final demonstration of the ML models was conducted by performing a simulation based on the Texas A&M Experimental Molten-Salt Bubbly Flow Loop. This comparison between traditional correlation-based models and the ML models demonstrated the enhanced predictive capabilities of the ML models for the prediction of both gas velocity and void fraction. The overall results showcased the feasibility of a ML-enhanced drift-flux model for molten salt-gas simulations.Mechanical Engineerin