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Molecular modeling investigation of water absorption in graphene oxide membranes and its impact on carbon dioxide separation
Get PDFPorous nanomaterials have attracted considerable attention due to their unique combinations of chemical and physical properties in various fields of research including absorption, separation, sensing and catalysis. Diverse applications require specific pore volume and pore size distribution that could be tuned by different fabrication methods. While new techniques have been actively developed and tested for controlled synthesis of nanoporous materials, the progress of their applications has been rather slow, mainly due to a lack of fundamental understanding of the nature and properties of the complex porous materials. Moreover, unintended molecules such as water would be absorbed into the porous structures under ambient conditions. The water absorption has often been ignored despite its importance. My research has primarily focused on developing a better understanding of water absorption in the porous materials and its impact on gas separation using molecular simulations. First, we examined water vapor absorption in graphene oxide (GO) laminates which have gained significant attention as a promising membrane material for gas separation. We have developed a new strategy for chemical potential prediction via direct calculation of Gibbs free energies and successfully applied it to predict the amount of water adsorbed in GO at equilibrium with its humid environment. From the molecular modeling investigation, we have also identified the key influencing factors on the water vapor sorption under various humid conditions. Next, we investigated the gas permeation and separation properties of GO laminates. While showing promise as a membrane material, our simulation results highlight that the performance of GO membranes, especially for CO₂ separation from flue gas, can be substantially enhanced by water absorption. We have also identified that the structural modification of GO with amine functional groups is an effective way to improve the CO₂ separation performance. The amine groups grafted on GO basal plane tend to act as spacers; the expanded interlayer spacing results in a water absorption increase. Lastly, our newly developed computational approach was applied to predict water adsorption on amine-functionalized silica that is considered as a promising solid solvent for CO₂ capture. The water adsorption is found to be sensitive to the type and density of surface functional groups (such as amine and hydroxyl groups), while the adsorbed water plays an important role in CO₂ capture. The work in this dissertation presents an overview of new insights from molecular simulations into mechanisms for water absorption in porous nanomaterials and its impact on CO₂ separation.Chemical Engineerin
The lettuce monster : a history of state violence, carceral geography and industrial agriculture in the Salinas Valley
Get PDFThis dissertation is a descriptive account of state violence in the Salinas Valley, a rural agricultural area on California’s Central Coast, from the 1930s to the 2010s. Chapter 1 recounts the 1934 Filipino lettuce strike and the 1936 Dust Bowl migrant strike to track how valley law enforcement departments expanded in man- and fire-power, and instituted surveillance tactics that were advanced for their time. It also examines how agribusiness leaders funded and directed strike suppression activities, and facilitated law enforcement’s acquisition of tear gas and long-range guns. These events contributed to making Salinas Valley law enforcement one of the most armed and organized forces in the nation by the end of the 1930s. Chapter 2 highlights valley law enforcement’s partnerships with federal and military agencies during World War II, as well as agribusiness’s use of Bracero and Prisoner of War labor. This chapter argues that the Salinas Valley developed a carceral geography that enabled high levels of agricultural production during the war. Chapter 3 follows the transformation of the carceral geography to include field and factory worksites, as undocumented immigrants were housed in labor camps resembling prison camps and were surveilled by growers’ private security guards, regional Border Patrol agents, and United Farm Workers strikers. Undocumented immigrants constituted a marginalized workforce that was exploited and faced dangerous work and living conditions into the 1980s. Formerly incarcerated people also form part of this workforce, and are subject to hyper-surveillance inside agricultural packing factories, and in public spaces subject to city ordinances and state probation laws. Chapter 4 examines Salinas Valley law enforcement’s increased militarization post-9/11, which was facilitated by the expansion of the Department of Defense’s 1033 Program and state and federal funding. A culture of impunity in the valley enabled law enforcement to engage in a series of unethical policing practices and financial scams, ultimately escalating to a spate of police shootings from 2014 to 2019. This dissertation ends considering how current pandemic-related measures affect policing and surveillance in the valley.American Studie
Richards Piano Roll Collection finding aid
No full textThis collection includes 857 player piano rolls from a variety of brands, including but not limited to Ampico, Welte Mignon, 88-Note Themodist-Metrostyle, and QRS.UT Librarie
Mediating images : UNESCO's photographic projects, 1946-1956
No full textIn this dissertation, I examine how UNESCO’s Department of Mass Communication mobilized photography and photographic exhibitions as mass media tools from 1946 to 1956. As the first study dedicated to UNESCO’s photographic projects, my dissertation examines how the Department of Mass Communication organized, developed, displayed, and circulated select exhibitions and visual media during UNESCO’s first decade. The UN entrusted UNESCO with the mission of fostering “world citizens”; one of UNESCO’s central tasks was to develop media that could reach constituents all over the world and compel them—no matter their nationality or political affiliation—to subscribe to its ideology. Both organizations faced the extremely difficult challenge of converting the “man-on-the-street” to their one-world cause. I explore how the Department of Mass Communication adjusted to the rapidly changing world of the late 1940s and 1950s and mediated the tensions of the period by nimbly adapting the content and form of many of UNESCO’s visual projects. As the first attempt to grapple with this unwritten history, this dissertation presents an institutional history of UNESCO’s Department of Mass Communication and considers how internal and external social, political, and aesthetic forces influenced UNESCO’s photographic exhibitions and print media. UNESCO’s work with photographs took place in museums, trade fairs, exhibitions halls, schools, and adult education centers in the form of exhibitions, albums, poster and postcard sets. Historiographies documenting exhibitions of the period regularly overlook these ephemeral exhibitions to focus on larger and more spectacular presentations of photography. This dissertation illuminates the complex history of UNESCO’s ambitious exhibition programs and establishes that UNESCO’s mobilization of photography as a diplomatic tool helped found and foster a visual culture of universalism.Art Histor
Static push-out tests and finite element studies on larger diameter shear studs for composite steel bridges
Get PDFEfficient steel bridge girder design makes use of composite action between the concrete bridge deck and the steel girders. The critical link between the deck and the girders are shear studs welded to the girder top flange. The most commonly used shear studs have a 7/8-inch diameter and are welded to the top flange of the beam in a fabrication shop or in the field. A very large number of shear studs is typically needed to satisfy AASHTO fatigue requirements. The large number of shear studs on beams makes the placement of partial depth precast concrete deck panels difficult. The large number of shear studs also create a safety hazard for workers during erection and early stages of construction due to limited space to walk on the flange. Using larger diameter shear studs can significantly reduce the number of studs required on composite steel girders, thereby enhancing construction safety and facilitating the increased use of precast deck panels on steel bridges. This dissertation is part of a larger research project examining the feasibility of using shear stud diameters greater than 7/8-inch for composite steel bridge construction, and the development of design guidelines for evaluating the static and fatigue strength of larger diameter shear studs. Shear stud diameters up to 1-1/4 inch were considered in the research project. The focus of this dissertation is two major contributions to the larger research project described above. These two contributions are conducting an extensive series of push-out tests and conducting detailed finite element studies of the behavior of shear studs embedded in concrete bridge decks. An extensive series of push-out tests were conducted to collect experimental data on the static loading behavior of larger diameter shears studs. These tests focused on 1-1/8-inch diameter studs, but also included tests on 7/8-inch dimeter studs for baseline comparisons. The static push-out tests generated data on load-slip behavior of the studs to characterize the stiffness, strength, and slip capacity of the studs. The tests explored a number of variables, including stud layout, deck reinforcing details, and stud penetration into concrete deck. Tests were conducted on full-depth cast-in-place decks as well as decks constructed using partial depth precast concrete panels. This dissertation also includes finite element analysis (FEA) of the local behavior of shear studs embedded in a concrete bridge deck. The commercially available FEA package Abaqus was used for this task. A variety of modeling approaches were explored, and the push-out test results were used for assessing model performance and accuracy. The load-slip response and failure modes of the test specimens were compared with model predictions. Once validated modeling approaches are established, parametric studies were done to further explore design variables not included in the experimental push-out tests.Civil, Architectural, and Environmental Engineerin
Doctoral thesis recital (piano)
No full textSonata no. 31 in A♭ major, op. 110 / Beethoven -- [Three unidentified works for solo piano]MusicName of supervisor not provide
Morphology control in the preparation of high-performance asymmetric membranes via nonsolvent-induced phase separation
Get PDFNonsolvent induced phase separation (NIPS) is the principal technique for manufacturing high-performance asymmetric polymeric membranes. Asymmetric membranes are characterized by a selective skin layer surmounting an open, porous support layer. Since penetrant flux is inversely proportional to the selective layer thickness, the skin must be made thin (i.e., ~100 nm) to ensure high productivity. Although sublayers are generally of secondary importance relative to skin layers in asymmetric membrane design, their morphology can profoundly impact a membrane’s mechanical stability, flux, and, in some cases, separation factor. Thus, extracting maximum performance from an asymmetric membrane requires complete control over skin and support layer evolution during NIPS. Presently, casting solution formulation and asymmetric membrane fabrication are qualitative trial-and-error processes performed with a relatively small group of well-understood polymers, solvents, and nonsolvents. Thus, no effective quantitative insights are available for efficiently optimizing membrane technologies developed from novel polymers or solvents. In the first part of this study, a technique for rapidly quantifying the content of large, finger-like voids in asymmetric membrane support layers (i.e., macrovoids) was proposed and validated. This technique was used to characterize 159 membranes prepared from 34 membrane-forming systems (i.e., unique combinations of nonsolvent, solvent, and polymer). Statistical regression analysis with variable selection was performed to generate macrovoid formation models and identify the most critical predictors of macrovoid initiation and growth. Casting solution viscosity and thermodynamic nonsolvent-solvent compatibility were identified as the most important predictors of macrovoid formation from an initial group of 24 regressors. High-performance polysulfone and polyimide flat sheet asymmetric gas separation membranes were prepared using dihydrolevoglucosenone (CyreneTM), a potentially benign alternative to other solvents traditionally used in membrane manufacturing, as the primary solvent in NIPS casting solutions. Importantly, CyreneTM, exhibited poor miscibility with the water nonsolvent/coagulant and produced viscous casting solutions, which were previously identified as critical parameters for suppressing macrovoid formation. Thus, resulting asymmetric membranes could be prepared with defect-free skin layers and complete control over macrovoid content. Additionally, polymer blends based on polybenzimidazole and a thermally-rearrangeable triptycene-containing poly(hydroxyimide) were characterized. These blends exhibited promising performance for pre-combustion carbon capture but require further optimization. Strategies for generating defect-free asymmetric gas separation membranes from these materials are also discussed.Chemical Engineerin
Chasing efficiency in the era of large language models
No full textAdvancements in efficient ML techniques have demonstrated immense potential not only in the production of cost-effective and environment-friendly models, but also in the notable democratization of AI technologies. Model compression algorithms are instrumental in addressing two seemingly conflicting goals of modern AI: scaling up our deep networks, while satisfying energy consumption restrictions and demanding constraints for production systems. This dissertation contributes to efficient ML research by developing task-centric evaluation protocols tailored for compressed LLMs and designing three novel LLM compression algorithms to improve LLMs' efficiency while minimizing performance degradation. Specifically, this two-part dissertation focuses on two complementary aspects of advancing efficient ML. First, Part I (Chapter 2 & 3) focuses on the existing challenges and limitations in the evaluation settings of state-of-the-art compression algorithms. Chapter 2 develops an automated evaluation framework (LLM-KICK) to define a realistic evaluation setup for compressed LLMs and facilitate a comprehensive assessment of the merits and limitations of SoTA compression algorithms. In addition, Chapter 3 investigates how different compression techniques impact LLMs' abilities to handle tasks of increasing difficulty. Second, motivated by the findings from LLM-KICK developed in Part I, this dissertation reassesses the design choices of existing compression techniques such as missing connection to LLM pretraining dynamics, uniform compression across all LLM components, etc. Part II presents three novel LLM compression algorithms: (1) Chapter 4 builds WeLore, which unifies a novel non-uniform layer-wise LLM compression technique (WeLore-COMP) with a parameter-efficient recovery mechanism (WeLore-PEFT) for GPT-style architectures; (2) Chapter 5 designs MC-Suite, which is a collection of expert importance estimation strategies for expert-level sparsification in MoE-style architectures; (3) Chapter 6 develops FFN-SkipLLM, which aims to achieve efficiency at inference subject to the non-uniform computational demand of decoded tokens by skipping feed-forward components. By addressing two complementary objectives of evaluation and novel algorithm developments, this dissertation draws the attention of the efficient ML community towards the potential to improve existing SoTA compression algorithms by equipping them with better evaluation setups and establishes that cues from LLM pre-training can be vital for developing robust novel algorithms.Informatio
Analysis of multi-stakeholder, 3D documentation and XR projects for heritage in the Indian context
No full textThe practice of historic preservation is constantly evolving with new technologies such as 3D laser scanning, photogrammetry and extended reality applications used for documentation, interpretation, and preservation of heritage. Even as these technologies are becoming ubiquitous around the world, they are being used piecemeal in India, a country known for its technological expertise such as in the IT industry and aeronautics. This research is an inquiry into this phenomenon, to understand the reasons behind the haphazard and sporadic use of these new technologies for historic preservation in India. This dissertation answers the question: What are the aspects that need to be considered, in the Indian context, for a 3D heritage documentation project to create a long-term, context-driven, technically relevant, and practical endeavor? The research process consisted of site visits for data collection and study of digital documentation project reports, conducting semi-structured interviews of relevant stakeholders such as project associates, government officials, relevant conservation experts, and tech startup personnel, analyzing heritage related government agency functioning and recruitment policies, and taking an overview of digital humanities education in India. The case studies analyses focused on pre-documentation - planning stages of the project, initiatives; post-documentation - data post-processing and applications for heritage conservation; and finally, data stewardship practices.
This dissertation presents possible reasons for problems facing successful digital documentation projects in India, ranging from bureaucratic red tape, pervasive apathy in archiving and consequently in providing future access to the data, lack of access to expensive hardware and software, and paucity of digital humanities experts. Further, there are issues such as systemic hierarchical prejudice in multistakeholder projects between technical and non-technical – read STEM and Humanities experts, lack of interdisciplinary learning mechanisms, and dearth of collaborative, synergistic project planning and implementation, amongst others. In the end, it offers suggestions to tackle some of these issues.Architectur
Kiez Love
No full textKiez Love is a selection of charcoal drawings I made this summer, aside references
pulled from the University of Texas at Austin Fine Arts Library. This case exhibition
brings together observations and abstractions drawn in different sites during an artist
residency in Berlin, Germany: a skatepark, a pond, and a botanical garden.
Working amongst shifting environmental elements is inspiring to the gestures and
images I make. These drawings exist in small sizes because they could fit into my
backpack; Carrying a drawing around with me to various locations is one of my habits.
Air entangling with leaves overhead, scents emitting from old fountain water, itchy
grass, restlessness and waiting in humidity, all inform how the drawings come into
being.
The pages left open for the books on display correlate to the drawings surrounding
them. I leave books open to images of significance during the development of projects
in my studio. I draw, then I seek related historical and contemporary contexts that
situate and guide my work. When I started drawing in charcoal recently, I sought out
artistic references which involve black and white imagery, ambiguity, and abstraction.Studio Ar