VictorJuiz/thesis huggingface dataset:
Electrochemistry of oxygen with lithium and protons [electronic resource]

The focus of this thesis is to identify the fundamental limitations associated with the electrochemistry of oxygen with lithium and protons based on computational modeling of the underlying processes. These have important implications for lithium-air batteries and fuel cells. We have examined three critical questions relating to the practicality of lithium-air batteries namely (i) Cycle efficiency, (ii) Deep discharge and (iii) Rechargeability. The key performance limitations were identified through a close coupling between experiments and theoretical modeling. We have developed a thermodynamic analysis based on density functional theory calculations to understand the reduction of oxygen with protons to water. Based on this analysis, we have identified a fundamental limiting overpotential of 0.37 for this reaction. We also show that this analysis can be used to understand trends in selectivity between the 4e- reduction to water and 2e- reduction to hydrogen peroxide. This analysis has been used to rationalize nearly 30 years of experiments on the catalytic activity of single crystal metal surfaces.

Keywords: Mechanical Engineering.
Advisor: Noerskov Jens
Pitsch Heinz
Jaramillo Thomas Francisco advisor. Thesis advisor
Prinz F. B. advisor. Thesis advisor
Electronic skin [electronic resource] : flexible and stretchable organic electro-mechanical sensors for robotics, wearable electronics and health monitoring

The natural biological skin's sensor performance presents tremendous challenges to emulate on artificial, electronic systems. High sensitivity, stretchability, and self-repair are salient characteristics of natural skin that, if re-created on artificial electronic skins can empower robotics, wearable devices, and biomedical applications. Organic materials that are inherently soft, flexible, or elastic are useful starting materials to use for artificial electronic skins. In this thesis, we explore the use of soft, elastic rubber as building blocks for force/pressure sensors. In particular, we developed highly sensitive capacitive pressure sensors, and in combination with organic semiconductors, created the first pressure-sensitive organic field effect transistors with unprecedented sensitivity and speed. Our sensors can detect static pressures as small as 3 Pa with milisecond response times. We performed finite element modeling to understand how the shapes of the elastic rubber impacts mechanical sensitivity, and describe the use of soft lithography techniques as a scalable means of manufacturing such elastic shapes. We further developed such organic field effect pressure sensors on flexible substrates that can be integrated onto smart bandages to monitor the human pulse when placed on the radial artery near the wrist. To enable stretchable pressure sensors, we developed a technique to create surface buckling of carbon nanotubes. The buckled nanotube films are highly stretchable and transparent, achieving greater than 2,200 S/cm and stretchable up to 150% strains. In addition, we demonstrate the first repeatably self-healing electronic skin using a supramolecular organic-inorganic composite. We developed the self-healing material using a composite approach, and achieved a conductivity as high as 40 S/cm. The composite material is mechanically flexible, and is capable of sensing tactile and flexion forces. Lastly, we propose using organic transistors to build oscillatory circuits that respond to pressure in a similar fashion to that of biological touch receptors. We call our system Digital Tactile Sensors (DiTACTS). The DiTACT prototype sensor generates a frequency of about 0 - 200 Hz, with the frequency being proportional to the pressure applied. Thus, DiTACTS encodes pressure information using frequency encoding, similar to that of slow-adapting biological touch receptors.

Keywords: Electrical Engineering.
Advisor: Bao Zhenan primary advisor. Thesis advisor
Nishi Yoshio
Poon Ada Shuk Yan
Electronic transport in topological insulator nanostructures [electronic resource]

Topological insulators are states of quantum matter with an insulating gap in the bulk and gapless surface states. The exotic spin nature of the surface electrons, resulting in topological protection from localization, suggests unconventional applications in electronics as well as fundamental scientific interests. While these exotic states have been investigated via surface-sensitive techniques intensively, electronic transport device, crucial to realize topological electronics, has lagged behind due to material challenges in candidate materials. Topological insulator nanostructure is an attractive candidate for device applications, as the size effect and boundary conditions offer a unique way to enhance / tailor the surface electron transport. In this dissertation, we first describe the design principle of topological insulator nanomaterials, with an emphasis on bismuth selenide. Two major material challenges, dominant bulk electron contribution and low surface mobility due to surface oxidation, are discussed and the solutions via nanomaterial synthesis are achieved. Elemental doping and core-shell heterostructures are developed to suppress bulk carriers and to achieve high surface electron mobility. The high electronic mobility allows us to observe Shubnikov-de Haas oscillations originated from the surface Dirac fermions. In addition to the material development, we also investigate transport properties from helical nature of the surface electrons. 1D modes of surface electrons in bismuth selenide nanowire Aharonov-Bohm interferometers is a unique electronic state providing an opportunity to reveal helical spin nature and topological protection via transport. The helical 1D mode, directly observed near the Dirac point under half magnetic flux quantum, is robust against disorder but fragile against a magnetic field breaking time-reversal-symmetry. The newly discovered 1D helical mode is expected to open a new direction to study topological electronics, as well as future applications.

Keywords: Applied Physics.
Advisor: Cui Yi
Harrison Walter A. (Walter Ashley)
Qi Xiaoliang advisor. Thesis advisor
Elucidating toxoplasma gondii's engagement with the host [electronic resource] : identification of dense granule protein 25 (GRA25), a novel member of the parasite's arsenal and characterization of strain-specific differences in the modulation of host immune responses

The ubiquitous parasite Toxoplasma gondii has developed an exquisite arsenal of effectors to support its intracellular lifestyle and its persistence within its diverse hosts. In order to survive and resist clearance, this obligate intracellular parasite must contend with the host immune response. Different strains of the parasite vary dramatically in their interaction with the immune system, and studying these strain differences has furthered our understanding of the spectrum of host-pathogen interactions and led to the identification of parasite effectors. The work described here dissects the interactions between different strains of the parasite and host macrophages: innate immune cells that paradoxically both serve as a niche for parasite replication and defend the host against parasite infection. Chapter 1 introduces Toxoplasma, the immune response to infection, and discusses the role of known parasite effectors. Experiments described in Chapter 2 identify a novel secreted parasite factor, GRA25, which modulates cytokine secretion in macrophages and controls parasite virulence in mice. In Chapter 3, high throughput methods are used to characterize the transcriptional and phosphorylation landscape of macrophages infected with different Toxoplasma strains. These analyses demonstrate that a secreted polymorphic tyrosine kinase, ROP16, directs murine macrophage polarization towards an alternatively activated phenotype. They also reveal that Toxoplasma parasites activate the Type I interferon response, a response classically associated with cytosolic pathogens. Chapter 4 describes work demonstrating that Toxoplasma strain-specifically modulates the innate immune response via secretion of a parasite factor, MAF1, which recruits host mitochondria to the parasitophorous vacuole. Finally, Chapter 5 discusses the future directions and implications of this work in the broader context of host-pathogen interactions.

Advisor: Boothroyd John C. primary advisor. Thesis advisor
Butte Atul J. advisor. Thesis advisor
Chien Yueh-Hsiu
Schneider David (David Samuel)
The emergence of infratactility in live performing arts [electronic resource]

This dissertation investigates how contemporary theater and aesthetic performance engage the five senses of both performers and spectators by evoking a feeling of primordial tactility of the human species (regarded both phylogenetically and ontogenetically). More specifically, it seeks out art works that deploy what media theorist Mark Hansen calls "infratactility, " pieces in which the body functions as the framer of information and the "coprocessor" of digital information. Digital coding that has become so prevalent in our lives and art practices simultaneously endanger and enrich the often fragile and elusive material world we tend to think of as live theatrical performance. In analyzing recent live performance works that implement the use of the theremin, robot-administered ingestion, smell-art and contact improvisation or those that − for the first time in the history of theater − were made specifically for (and with) infants, the goal of the dissertation is to suggest the ways live performance responds to the unprecedented threat of total irrelevance that humans face now that their bodies are no longer able to keep pace with the speed of technical vision. The author argues that the performance strategies he discusses serve the recent live performance in reinforcing perceptuomotor activities and expanding the range of perception well beyond the organic-physiological constraints of human embodiment.

Keywords: Theater and Performance Studies.
Advisor: Jakovljević Branislav primary advisor. Thesis advisor
Phelan Margaret (Barrister)
Rayner Alice primary advisor. Thesis advisor
Empirical analysis of the impact of tick sizes on exchange efficiency [electronic resource]

The welfare gains that a securities exchange delivers to participants is influenced by regulatory and design decisions. One feature of an exchange that is determined by such decisions, for example, is the tick size. I develop two approaches to empirically analyzing the impact of a tick size reduction on exchange efficiency, measured in terms of average per trader gain. For the first approach, I estimate the impact of a tick size reduction using historical data before and after the reduction. I apply this approach to study the impact of a past tick size change and find that, contrary to the common belief that motivates tick size reductions in many securities markets, the overall exchange efficiency decreased after the tick size reduction. For the second approach, I predict the impact of a tick size reduction on a securities market using historical data from the market under the current tick system together with the incremental gradient method and simulation techniques. I test this approach by using it to predict the changes in efficiency after a historical tick size reduction and comparing the predictions to what can be inferred from historical data. The results show strong correlations between the predictions and the estimates obtained from historical data.

Keywords: Management Science and Engineering
Advisor: Van Roy Benjamin primary advisor. Thesis advisor
Johari Ramesh
Nagel Stefan
Energy stable high-order methods for simulating unsteady, viscous, compressible flows on unstructured grids [electronic resource]

High-order methods have the potential to dramatically improve the accuracy and efficiency of flow simulations in the field of computational fluid dynamics (CFD). However, there remain questions regarding the stability and robustness of high-order methods for practical problems on unstructured triangular and tetrahedral grids. In this work, a new class of 'energy stable' high-order methods is identified. This class of schemes (referred to as the 'Energy Stable Flux Reconstruction' class of schemes) is proven to be stable for linear advection-diffusion problems, for all orders of accuracy on unstructured triangular grids in 2D and unstructured tetrahedral grids in 3D. Furthermore, this class of schemes is shown to be capable of recovering the well-known collocation-based nodal discontinuous Galerkin scheme, along with new schemes that possess explicit time-step limits which are (in some cases) more than 2x larger than those of the discontinuous Galerkin scheme. In addition, the stability of the Energy Stable Flux Reconstruction schemes is examined for nonlinear problems, and it is shown that stability depends on the degree of nonlinearity in the flux and on the placement of solution and flux points in each element. In particular, it is shown that choosing the solution and flux point locations to coincide with the locations of quadrature points promotes nonlinear stability by minimizing (or eliminating) nonlinear aliasing errors. A new class of symmetric quadrature points is identified on triangles and tetrahedra for this purpose. Finally, the Energy Stable Flux Reconstruction schemes and the new quadrature points are applied to several nonlinear problems with the aim of assessing how well the schemes perform in practice.

Keywords: Aeronautics and Astronautics.
Advisor: Jameson Antony
Farhat Charbel advisor. Thesis advisor
MacCormack R. W. (Robert William)
Engineering bacterial populations via DNA messaging [electronic resource]

Evolution has selected for organisms that benefit from genetically encoded cell-cell communication. We observe cell-cell communication throughout every scale in nature, from simple single-celled bacteria to complex multicellular mammals. Engineers have begun to repurpose elements of natural communication systems to coordinate their own population-level behaviors, including oscillations and programmed pattern formation. Existing engineered systems, however, rely on small, system-specific biomolecules to send messages among cells. However, such molecules are capable of sending only a single message, typically ``regulate transcription.'' Thus, the information transmission capacity of such biological communication systems is fundamentally limited. Through this thesis, I demonstrated the decoupling of messages from a common communication channel via the autonomous transmission of numerous arbitrary genetic messages. To do so, I engineered a cell-cell communication platform using bacteriophage M13 gene products to autonomously package and deliver heterologous DNA messages of varying lengths and encoded functions. Further, I increased the range of engineered DNA messaging across semisolid media by coupling message transmission or receipt to active cellular chemotaxis. Through this coupling, I demonstrated that our system is adaptable to different contexts by creating simple patterns. Finally, using recombinase-mediated logic gates developed within the Endy laboratory, I demonstrated the ability to program bacteria by transmitting logic gates to surrounding cells. Overall, this work significantly enhances the suite of cell-cell communication tools available to engineers. I have shown that a variety of DNA messages can be transmitted among cells and have moved the field of synthetic biology closer to designing synthetic ecologies with more complex communication schemes and varied behaviors.

Keywords: Bioengineering.
Advisor: Endy Andrew D. primary advisor. Thesis advisor
Fisher Daniel S. advisor. Thesis advisor
Riedel-Kruse Hans advisor. Thesis advisor
Engineering quantum systems with coherent feedback control [electronic resource]

The control of quantum dynamics in which feedback is accomplished via coherent, all-optical signal processing suggests the possibility of mature, engineered quantum systems that are technologically homogeneous and in which both plant and controller are quantum systems. In this thesis, I give a focused case study of several systems in which feedback control of the system dynamics is accomplished entirely through field-mediated, coherent signal processing. I describe some recently developed theoretical tools for modeling individual and networks of open quantum systems, and analyze the applications of coherent quantum feedback to squeezed-light generation and quantum error correction.

Keywords: Applied Physics.
Advisor: Mabuchi Hideo primary advisor. Thesis advisor
Ganguli Surya
Yamamoto Yoshihisa advisor. Thesis advisor
Entropy, stress, and collapse [electronic resource] : mechanics of the gram-positive bacterial cell envelope

This thesis examines three topics that are related to the Gram-positive bacterial cell envelope. First, I examine how transmembrane proteins navigate through the thick, heavily cross-linked Gram-positive cell wall while remaining anchored to the bacterial membrane. I develop a theoretical model that predicts that entropic confinement of a disordered protein can drive translocation through the cell wall. I experimentally test important predictions of the model to demonstrate that translocation depends on the length of the translocating protein and the geometry of the bacterial surface, while demonstrating that entropy-driven translocation occurs in a variety of Gram-positive species. Second, I study how the antimicrobial peptide nisin causes cell death in Gram-positive bacteria. I demonstrate that nisin treatment triggers membrane collapse in multiple Gram-positive species, and provide evidence that collapse is initiated by an increase in compressive stress in the membrane. Finally, I examine the process of cell division in the Gram-positive coccus Staphylococcus aureus. Contrary to the current view of S. aureus division, cell volume increases monotonically during the cell cycle, as opposed to occurring entirely during cell separation. I observed a dramatic millisecond hemisphere-to-sphere transition during cell separation that was accompanied by a decrease in surface area, suggesting that separation is associated with a redistribution of cell wall stress.

Keywords: Microbiology and Immunology.
Advisor: Theriot Julie primary advisor. Thesis advisor
Huang Kerwyn Casey
Monack Denise M. advisor. Thesis advisor
Schneider David (David Samuel)
Equivariant torsion and base change [electronic resource]

The Cheeger-Muller theorem provides a spectral means of obtaining information about torsion in the cohomology of compact manifolds. Using this remarkable theorem together with trace formula comparisons, we prove comparisons between torsion in the cohomology of two manifolds of arithmetic origin related by base change.

Keywords: Mathematics.
Advisor: Venkatesh Akshay
Church Thomas (Thomas Franklin) advisor. Thesis advisor
Conrad Brian
Escaping the double bind [electronic resource] : self-reliance is a distinct and positive form of agency for women in organizations

Four experiments test the idea that self-reliance is a functional form of agency for women in organizations. Drawing on theories of interpersonal perception and group based stereotypes, this paper suggests that women face backlash for displaying agency related to competition and hierarchy (e.g., dominance), but not for displaying agency unrelated to competition and hierarchy (e.g., self-reliance). This is because only displays of the former evoke negative assessments of women's trustworthiness. Participants judged male and female targets to be similarly competent when they displayed high levels of either self-reliance or dominance (Studies 1-4). But, whereas they judged male targets to be similarly trustworthy regardless of the type of agency they displayed, they judged female targets to be more trustworthy when they displayed self-reliance than when they displayed dominance (Studies 1-4). Consequently, participants were more likely to hire (Study 2), to vote for (Study 3), and to invest in the company of (Study 4) a woman when she displayed self-reliance than they were when she displayed dominance. Participants made no such distinctions between men that displayed self-reliance and men that displayed dominance. Moreover, whereas there was evidence of backlash against women that displayed dominance in three of the four studies, there was no evidence of backlash against women that displayed self-reliance in any of the studies. These findings suggest that by framing agency as self-reliance female leaders may be able to demonstrate competence without a cost.

Keywords: Business.
Advisor: Flynn Francis J. primary advisor. Thesis advisor
Lowery Brian
Tiedens Larissa Z.
Essays in applied microeconometrics [electronic resource]

This subject of this dissertation is applied microeconometrics. Chapter 1 estimates the effect of physician incentives on treatment choices in heart attack management. Our results suggest that if physicians received bundled payments instead of fee-for-service incentives, heart attack management would become considerably more conservative, and about 20 percent of patients would receive different treatments. Chapter 2 studies the effect of Medicaid on health expenditures. At age 19, some enrollees lose Medicaid eligibility. We find that this quasi-experimental loss of coverage causes substantial changes to the level and composition of health care use. Average health expenditure falls by around 60 percent. Chapter 3 compares set-asides and subsidies in government procurement auctions. Restricting entry appears to substantially reduces efficiency and revenue, although it increases participation of favored bidders.

Keywords: Economics.
Advisor: Einav Liran primary advisor. Thesis advisor
Levin Jonathan D. (Jonathan David)
Hoxby Caroline Minter advisor. Thesis advisor
Essays in behavioral finance and online markets [electronic resource]

In this dissertation I study a number of questions in behaviroal finance and online markets. In the first chapter, I empirically analyze why people hold expensive credit card balances, often over substantial time horizons. Specifically, I test whether hyperbolic discounting can explain why many consumers are not able to reduce their credit card debt. In the second chapter, I analyze the effect of potential market misvaluation for corporate acquisitions when some managers are overoptimistic. I focus on the implications for the method of payment and the implications for subsequent returns depending on the method of payment chosen. In the third chapter, joint work with Liran Einav, Jonathan Levin and Neel Sundaresan, we study seller experiments in online markets. We document the prevalence of pricing and auction design variation for listings on eBay. We show how this variation can be used to learn about questions of consumer behavior and market outcomes, while leveraging the scale and heterogeneity of online markets.

Keywords: Economics.
Advisor: Levin Jonathan
Einav Liran advisor. Thesis advisor
Hoxby Caroline Minter advisor. Thesis advisor