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Glass Based Packaging for Beyond 5G Communication
No full textThe objective of this research is to develop advanced glass packaging technology to enhance the performance of RF front-end (RFFE) modules in the D-band (110 GHz to 170 GHz) for next-generation wireless communication (6G). The focus is on heterogeneous integration solutions for 140 GHz CMOS IC and Indium Phosphide (InP) power amplifier (PA) RFFE modules, demonstrating the superior performance of the first D-band PA-antenna module using advanced die-embedded glass substrate. This work addresses the challenges of antenna integration, interconnect loss, and thermal management. The innovative packaging solution leverages the advantages of glass substrates, including excellent thermal-mechanical reliability, fine feature size, and low cost for scalability to large arrays. By embedding the Si passive dies and InP PAs at the center of the glass substrate, the design facilitates ultra-short die-to-package interconnects through dielectric vias, achieving remarkably low loss at 140 GHz and excellent matching across the 110 GHz to 170 GHz frequency range. The design also accommodates the seamless integration of a microstrip patch antenna array. Moreover, the die-embedded glass package incorporates a copper heat spreader on the PA's backside, significantly enhancing thermal management. Compared to current packaging solutions for state-of-the-art D-band modules, this approach offers superior electrical and thermal performance and assembly simplicity. Additionally, this research explores novel interconnects, such as planar Goubau lines on glass substrates, to address on-package transmission challenges. With its outstanding electrical and thermal performance, scalability, and cost-effectiveness, glass packaging presents a promising solution for developing D-band beamforming arrays in next-generation communication systems.Ph.D.Electrical and Computer Engineerin
An Exploration of Titanium Oxide Hydrate/Polyalcohol Hybrids for Solar Energy Harvesting and Storage
No full textPhoto-rechargeable redox flow batteries are an emerging energy storage system that advantageously combines solar energy harvesting and storage capabilities into one device. This thesis explores inorganic/organic hybrids based on a liquid titanium oxide hydrate and various polyalcohols as novel photo-rechargeable redox flow battery electrolytes. Nuclear magnetic resonance spectroscopy suggested that the polyalcohol participates in the photoreduction mechanism of titanium oxide hydrate. Gas chromatography mass spectrometry on titanium oxide hydrate/glycerol hybrids enabled the development of a possible photoreduction mechanism for titanium oxide hydrate. Importantly, it is proposed that glycerol is consumed within this photoreduction reaction. Electrochemical and optical properties of titanium oxide hydrate/polyalcohol hybrids were also characterized. The voltage generated by these hybrids under UV illumination and their ability to store voltage without constant UV illumination were both dependent on the polyalcohol identity within the hybrid. Ultraviolet-visible spectroscopy and cyclic voltammetry suggested reasons for these electrochemical properties through potential differences in the stability of titanium(III). Overall, the knowledge presented in this thesis can promote a new class of photo-rechargeable redox flow battery electrolytes for more accessible solar energy generation and storage.UndergraduateChemical and Biomolecular Engineerin
Great Expectations: Bringing active learning to an academic library department
No full textThis is a PDF of the poster presented at the July 2025 Georgia Library Instruction, Teaching, and Reference Conference (GLITR) conference.The Academic Engagement department in the Georgia Tech Library is responsible for the majority of course-integrated instruction and workshops for the Institute. These sessions cover many topics, from data analysis to podcasting to information literacy. In the past, incorporating active learning techniques was the individual prerogative of each instructor. Now, active learning and universal design for learning (UDL) are requirements for teaching under the aegis of the Georgia Tech Library. The Instruction Manager, supported by the Head of Academic Engagement, developed a plan for introducing these concepts to seasoned and novice instructors alike. The Instruction Manager invited guest trainers for UDL, organized an instruction retreat for the unit focused on active learning, and fully overhauled the class request system for teaching faculty. This poster presents a case rolling out these active learning skillsets for an entire unit with buy-in from library faculty.
We will explore how to teach an entire unit—many of whom have no particular interest in pedagogy—active learning techniques by using active learning techniques. The Instruction Manager created a new, documented standard of success and clear expectations for the future. And for those who continue to be uninterested in pedagogy for its own sake, the proposed skillsets allow for them to choose teaching techniques that are known to be successful while they can focus on their subject matter expertise
Efficient Quantum Chemistry for Applications in Anharmonic Vibrational Analysis and Molecular Crystals
No full textQuantum chemistry can give invaluable quantitative insights into the properties
of molecular systems without the need for physical experimentation. However,
the poor algorithmic scaling of quantum chemistry methods restricts the most accurate methods to all but the smallest systems. Development of improved software, algorithms, and theoretical approximations can extend the size of molecules able to be studied computationally, an essential prerequisite for applications to real chemical systems.
In the first two chapters, we present open-source software for the computation
of the anharmonic vibrational frequencies of molecules using vibrational
perturbation theory. Through the use of focal-point approximations to estimate
complete-basis coupled cluster and novel software enabling automated distributed
computations, we are able to obtain anharmonic frequencies in a fraction of the time of alternative approaches without sacrificing accuracy. Computation of the
lattice energies of molecular crystals is another challenging application of
quantum chemistry methods. Chapter 4 explores the contributions of three-body
interactions in crystalline formamide, acetic acid, and imidazole. We
demonstrate the ability to obtain three-body contributions to the lattice energy
of molecular crystals at accuracy within 1 kJ/mol at a greatly reduced
compuational cost, using approximate methods and geometric screening of the
many-body expansion. Finally, we present results of a preliminary study of
virtual screening for G-protein coupled receptor targets, an important class of
pharmaceutically relevant proteins, using machine learning and cheminformatics
representations.Ph.D.Chemistry and Biochemistr
Understanding dynamics and distributions of poly(ethylenimine) confined in mesoporous SBA-15 silica and impact on CO2 capture
No full textSolid-supported amines serve as advanced CO2 sorbents, effectively balancing high CO2 uptake and energy-efficient regeneration. These materials enable CO2 capture, even from ultra-dilute sources such as ambient air, which contains approximately 420 ppm CO2. One exemplary sorbent model is poly(ethylenimine) (PEI) in SBA-15. In this sorbent, the physical attributes of PEI dictate its performance. The distribution of PEI determines the extent of amines available for reacting with CO2, determining equilibrium CO2 uptake, while PEI mobility controls the diffusion of CO2 through the PEI-packed pore space, ultimately influencing CO2 uptake rates. This thesis aims to characterize the distribution and motions of PEI confined in SBA-15, utilizing a combination of neutron scattering, solid-state NMR, and molecular dynamics (MD) simulation. First, the effects of different pore wall-PEI interactions are studied, revealing subtle interplays among PEI, solid walls, and wall-grafted chains that result in unique PEI structures and mobilities. Second, the underlying roles of poly(ethylene glycol) (PEG) additives are illuminated, providing insights into the unique behavior observed in CO2 sorption and desorption processes. Finally, the impacts of multiple cycles and the composition of the input gas are investigated, demonstrating that repeated thermal swings and humidity in the input stream lead to changes in PEI properties.Ph.D.Chemical and Biomolecular Engineerin
A Controllable Co-Creative Agent for Game System Design
No full textMany advancements have been made in procedural content generation for games, and with mixed-initiative co-creativity, have the potential for great benefits to human designers. However, co-creative systems for game generation are typically limited to specific genres, rules, or games, limiting the creativity of the designer. We seek to model games abstractly enough to apply to any genre, focusing on designing game systems and mechanics, and create a controllable, co-creative agent that can collaborate on these designs. We present a model of games using state-machine-like components and re- source flows, a set of controllable metrics, a design evaluator simulating play-throughs with these metrics, and an evolutionary design balancer and generator. We find this system to be both able to express a wide range of games and able to be human-controllable for future co-creative applications.UndergraduateComputer Scienc
Mechanical characteristic variation in microfluidic channels
No full textThe technological advances for the delivery of nanoparticles and other nanomaterials into cells has yielded promising results, however many of the current methods have major limitations, such as cell viability. An alternative method involves the use of microfluidic devices to induce rapid cellular compression, which disrupts the cell membrane. The operating gap size has shown to be an important factor for cargo delivery; however, higher flow rates have been shown to reduce the operating gap size due to PDMS deformation, which impacts the efficiency of cargo delivery. In this study, a relationship between flow rate and deformation is established, followed by a relationship in the device deformation and subsequent delivery efficiency of FITC Dextran to Jurkat cells. It is determined that a reduction in device deformation corresponds to an increase in delivery efficiency, and therefore improved device performance. These results suggest that making the switch from PDMS-based devices to epoxy resin would result in better device performance due to the stiffer material being more resistant to deformation.UndergraduateBiomedical Engineerin
Operations Research for Improved and Equitable Maternal Health
No full textThe United States' rate of pregnancy-related deaths is the highest among developed countries and is increasing, even as upwards of 80% of these deaths are preventable. Additionally, there are staggering racial/ethnic and urban/rural disparities in maternal outcomes. These poor health outcomes and persistent disparities point to systemic issues and the need for evidence-based systems-level solutions. The complexities of the United States' maternal healthcare system are extremely difficult to capture and study using classical methods in medicine and epidemiology. In this thesis, we present operations research approaches that are capable of incorporating these complexities to inform policy that optimizes the delivery of and access to maternal healthcare in the United States.
In the first technical chapter, we assess the racial and ethnic disparities in pre-pregnancy conditions and analyze their contribution to disparities in adverse maternal outcomes using data from an observational cohort of first-time mothers. Using logistic regression and causal inference methods, we find that non-Hispanic Black race/ethnicity is significantly associated with adverse maternal outcomes, which is consistent with existing literature. However, we find that accounting for pre-pregnancy conditions, specifically cardiovascular conditions, explains some of the elevated risk of non-Hispanic Black patients experiencing severe preeclampsia. This result suggests that the prevention and management of pre-pregnancy conditions could be an important factor in decreasing racial and ethnic disparities in adverse maternal outcomes.
In the remaining technical chapters, we focus on informing systems-level solutions to maintain and improve access to obstetric care. In the second technical chapter, we evaluate existing measures of access to obstetric care in the United States, including the county-based “maternity care deserts” measure. Using optimization models, we determine the implied facility location policy implications of these measures. In a state like Georgia, with many small counties, eliminating “maternity care deserts” would require a prohibitively large number of new obstetric hospitals, suggesting that additional tools are needed to estimate the optimal number and distribution of hospitals to meet obstetric care needs.
In the third technical chapter, we use mathematical modeling to better understand the implications of the widespread trend of obstetric hospital closures on travel distance to care and delivery volume of care. Most rural residents travel far distances for obstetric care and are more likely to deliver in hospitals with low delivery volume, which are associated with poor maternal outcomes. We propose a multi-criteria bilevel optimization model to characterize the trade-off between travel distance and delivery volume. We find that a single obstetric hospital closure would increase affected patients’ travel distance by an average of 4.6 miles but would decrease the proportion of deliveries that occur in low-volume rural hospitals from 8.1% to 6.9%, which may lead to maternal outcome gains due to consolidated delivery volume. This work emphasizes that travel distance and volume of care cannot be considered in isolation to maintain access to high-quality care.
In the fourth technical chapter, we extend our previous work to incorporate bypassing behavior, where pregnant women do not seek labor & delivery care at their closest obstetric hospital. We assume that pregnant women seek care according to a random utility maximization model, which we integrate into a facility location model to determine worst-case obstetric closures. This modeling framework, the Maximal Choice-Based Expectation Facility Location Problem, extends existing literature beyond the maximum capture objective to a generalized choice-based expectation. We explore the properties of this model and design decomposition methods to solve large-scale instances. We then use this framework to determine the obstetric closures that would maximize choice-based travel distance, to identify which obstetric hospitals are vital to maintaining access in a maternal healthcare system.
The overall objective of my thesis work is to better understand and improve the delivery of maternal healthcare at an individual and systems level to reduce adverse maternal health outcomes and disparities.Ph.D.Operations Researc
Advancing the Physical Internet with GraphRAG: A New Way to Review and Integrate Existing Research
No full textPhysical Internet (PI) is an emerging concept that applies the digital internet as a design metaphor for the development of sustainable, interoperable, and collaborative freight transportation. It is considered a way to bring logistics into the next generation of transformation. Effective tools for organizing and integrating knowledge are essential for navigating the emerging research in this area. In this study, we explore the application of Graph Retrieval Augmented Generation (GraphRAG) in the context of PI, using GPT-4o mini and Neo4j to construct a knowledge graph and systematically analyze existing PI-related literature. Our approach synthesizes scattered research findings, highlights emerging trends, and identifies knowledge gaps. Furthermore, we demonstrate that GraphRAG improves accessibility by structuring complex information into interconnected graphs and provides a deeper understanding of underlying research dynamics. This research will contribute to future research and innovation by providing a new method of information analysis in the PI domain