VictorJuiz/thesis huggingface dataset:
Printed and Flexible Systems for Solar Energy Harvesting

Emerging wireless and flexible electronic systems such as wearable devices and sensor networks call for a power source that is sustainable, reliable, has high power density, and can be integrated into a flexible package at low cost. These demands can be met using photovoltaic systems, consisting of solar modules for energy harvesting, battery storage to overcome variations in solar module output or load, and often power electronics to regulate voltages and power flows. A great deal of research in recent years has focused on the development of high-performing materials and architectures for individual components such as solar cells and batteries. However, there remains a need for co-design and integration of these components in order to achieve complete power systems optimized for specific applications. To fabricate these systems, printing techniques are of great interest as they can be performed at low temperatures and high speeds and facilitate customization of the components./nThis thesis discusses the development of printed and flexible photovoltaic power systems, spanning both device-level and system-level design. Photovoltaic cells and multi-cell modules are designed and manufactured using solution-processed organic materials. The use of carbon nanotube films as a flexible, low-cost, solution-processed transparent electrode for photovoltaics is investigated. Then, photovoltaic modules are integrated with batteries into energy harvesting and storage systems with multiple power levels and form factors, optimized to deliver power to loads such as wearable medical sensors. The energy collecting potentials of these systems are evaluated under indoor and outdoor lighting conditions. Designing the solar module maximum power point to match the battery voltage, as well as optimizing load characteristics such as duty cycle, are shown to enable power systems with long-term wireless operation and high efficiency. Finally, screen-printed passive components are developed and demonstrated in a hybrid flexible voltage regulator circuit. In particular, high-quality printed spiral inductors satisfactory for power electronics applications are achieved through optimization of the geometry and fabrication. Overall, the high-performance devices and integrated system designs demonstrated here have the potential for significant impact in the areas of flexible, portable and large-area electronics.

Advisor: Arias, Ana C
Electric field effects in combustion with non-thermal plasma

Chemically reacting zones such as flames act as sources of charged species and can thus be considered as weakly-ionized plasmas. As such, the action of an externally applied electric field has the potential to affect the dynamics of reaction zones by enhancing transport, altering the local chemical composition, activating reaction pathways, and by providing additional thermal energy through the interaction of electrons with neutral molecules. To investigate these effects, one-dimensional simulations of reacting flows are performed including the treatment of charged species transport and non-thermal electron chemistry using a modified reacting fluid solver. A particular area of interest is that of plasma assisted ignition, which is investigated in a canonical one-dimensional configuration. An incipient ignition kernel, formed by localized energy deposition into a lean mixture of methane and air at atmospheric pressure, is subjected to sub-breakdown electric fields by applied voltages across the domain, resulting in non-thermal behavior of the electron sub-fluid formed during the discharge. Strong electric fields cause charged species to be rapidly transported from the ignition zone across the domain in opposite directions as charge fronts, augmenting the magnitude of the electric field in the fresh gas during the pulse through a dynamic-electrode effect. This phenomenon results in an increase in the energy of the electrons in the fresh mixture with increasing time, accelerating electron impact dissociation processes. A semi-analytic model to represent this dynamic electrode effect is constructed to highlight the relative simplicity of the electrodynamic problem admitted by the far more detailed chemistry and transport. Enhanced fuel and oxidizer decomposition due to electron impact dissociation and interaction with excited neutrals generate a pool of radicals, mostly O and H, in the fresh gas ahead of the flame's preheat zone. The effect of nanosecond pulses are to increase the mass of fuel burned at equivalent times relative to the unsupported ignition through enhanced radical generation, resulting in an increased heat release rate in the immediate aftermath of the pulse.

Advisor: Chen, Jyh-Yuan
A Cosserat Theory for Solid Crystals – with Application to Fiber-Reinforced Plates

The focus of this thesis is to understand the behavior of composite plates reinforced with/nrigid bars that are free to twist and bend with respect to the medium. Such composites are/nubiquitous in nature and in industry, especially with increased interest in modeling biological elements as well as nano-technology. Structured fabrics abound in nature and industry – from cytoskeletons to kevlar sheets./nIn the first part of this thesis existing theory on such materials is reviewed. A particular/nmicrostructure - that of a fiber-reinforced medium - is the subject of further study. Such/na medium is treated as a special case of a nematic elastomer with constrained directors./nThe salient feature of such a material is the presence of only along-fiber derivatives in the/nproblem, precluding certain boundary data./nThe second part of the thesis focuses on the development of a two-dimensional plate/ntheory from the three-dimensional fiber reinforced medium studied previously. The resulting two-director model shows behavior similar to a nematic elastomer with directors that are unable to shear. This is then specialized to the case of a laminate with a single family of fibers. To obtain an understanding of the theory it is applied to a simple controllable deformation; that of a fiber-reinforced plate bent into a cylindrical shell. The orientation of the fibers is selected to result in both bending and twist. This controllable deformation helps us understand the possible boundary data and its e↵ect on the solution. The effect of boundary data on existence and uniqueness of solution is highlighted through the example problem.

Advisor: Steigmann, David J
The Development and Application of a High-throughput, High-content System for the Investigation of Stem Cell Biology

The field of stem cell science is one with enormous potential for impact in both therapeutic applications and in understanding human development and homeostasis. It is increasingly appreciated that stem cells and stem cell behavior are governed by a complex, interwoven network of environmental signals with variable spatial and temporal presentation. While conventional molecular and cellular biology techniques have provided a fundamental foundation for stem cell investigation, advances in the adaptability and through-put of future laboratory work flows will be necessary to address questions in this ever-expanding parameter space. The goal of this dissertation, therefore, has been to instantiate just such a platform, and provide proof of concept evidence as to its utility in stem cell investigations. Design considerations and pipeline engineering are discussed, and data collected with the system in benchmarking, dose-response, and combinatorial experimental formats are provided to illustrate the experimental work the platform enables.

Advisor: Schaffer, David
Circadian and Metabolic Influences on the Reproductive Axis

Reproduction is a hazardous and costly endeavor for female mammals. A classic evolutionary trade-off is created by the need to balance self-survival with the risks associated with reproduction. To maximize reproductive success and minimize risks, a myriad of cues are integrated by the reproductive neurocircuitry of the hypothalamus. The following studies investigate how cues from the circadian system, sex steroid hormones, and energy sensing systems impact reproductive physiology and behavior. These studies place particular emphasis on the RF-amide-related peptides, kisspeptin and gonadotropin inhibitory hormone. These neuron populations lie upstream of the gonadotropin releasing hormone system and are ideally situated to integrate information about time of day, cycle timing, and metabolic status. This feedback fine-tunes reproductive physiology and behavior to optimize reproductive success.

Advisor: Kriegsfeld, Lance J
The Constitutionalism of Ruhollah Khomeini's Theory of Guardianship

In this dissertation, I study the political thought of a scholar and political actor who has long been viewed as a cultural Other: Ayatollah Ruhollah Khomeini. To understand Khomeini’s thought, or the thought of any other culturally unfamiliar author, I argue that it is essential to engage in a historical study of the traditions of thought that the author interprets and elaborates. Through a study of many of Khomeini’s political writings—written as early as 1943 and as late as 1989—I have determined that Khomeini was influenced by four traditions of thought: the Shi’a jurisprudential tradition of political theory, the Usuli legal tradition, the Islamic constitutionalist tradition, and more marginally, the Islamic mystical-philosophical tradition./nAs a scholar of the Shi’a jurisprudential tradition of political theory, Khomeini holds that Islamic jurisprudents must be granted a powerful role in government. The secondary literature fails to recognize, however, the way in which Khomeini’s Islamic constitutionalist ideas impact his theorization of the political role of the jurisprudent, and at times, it incorrectly presumes that the guardian is the mystic or philosopher depicted in the Islamic mystical-philosophical tradition. As a constitutionalist, Khomeini argues that consent and popular representation are necessary ingredients of legitimate government and that the shari’a can be supplemented or aspects of it even suspended by law drafted in a parliament. Khomeini’s constitutionalism is based upon tenets of the Usuli legal tradition, which says that Islamic law is underwritten by principles from which can be deduced new law, law that is human and contestable./nThe influence of the Islamic constitutionalist tradition on Khomeini’s thought is most evident in his 1943 work, The Unveiling of Secrets, as well as in his post-revolutionary writings. Khomeini’s more widely read work, Islamic Government, does not include manifestly constitutionalist themes, but I argue that it has been misinterpreted to espouse ideas that contradict Islamic constitutionalism. Khomeini’s writings, as well as the institutions of government that were inspired by his theory, continue to be subjects of interest for conservative and reformist scholars and actors, and his writings are invoked for support for perspectives across the political spectrum. Beyond helping us to understand contemporary debates in the Islamic Republic, Khomeini’s political writings are a source of concepts and arguments that may be marshaled and elaborated in novel Islamic theories of government and politics.

Advisor: Bevir, Mark
Malarial Proximities: Senegal, the Pursuit of Evidence, and the Silver Revolver Approach to Global Health

Through the lens of malaria control and eradication efforts, this dissertation considers the political nature of demarcating global health problems and the pursuit of evidence to support such framings. By attending to past international campaigns to eliminate malaria and shifts in the goals of international health as a whole, I investigate what is new about what some have called the “silver revolver” approach to global health governance: the deployment of simple, technologically-innovative tools to attack a disease from multiple angles through the support of public-private partnerships. Based on fieldwork with health workers, biologists, public health officials, and recipients of care in and around Dakar, Senegal and with designers and funders of malaria interventions in California, Switzerland, and Italy, my dissertation shows what counts as knowledge and who frames possible futures in global health research, design, implementation, and evaluation. I argue that talking about malaria means getting close to malaria or speaking from the proximity of malaria, as the ecologies that malaria produces and that produce malaria vary greatly on the parasite’s and its hosts’ historical, political, and socio-economic contexts. Speaking of malaria on a global scale – in a project of global control or global eradication – means creating and maintaining conceptual proximities through the discourse of a single, unified “malaria” (Kelly and Beisel 2012). Examining the central role of the informal in malaria treatment, practices of approximation in malaria diagnosis, and the space for political resistance in health data collection in Senegal, I argue that attention to conflicts over malarial knowledge and practices is in fact crucial to dreams of malaria eradication, as well as to a “more democratic and equitable” global health (Geissler 2011).

Advisor: Hayden, Cori
The function of SIRT7 in cellular stress response and tissue maintenance

Until the last few decades, aging was thought to be the stochastic accumulation of errors not subject to any active regulation. However, recent evidence suggests that aging is under regulatory control and is subject to modulation by classical signaling pathways. These pathways include the insulin/IGF-1 pathway, the mTOR pathway, and sirtuins, whose up- or downregulation can trigger diverse cell-protective mechanisms against environmental and physiological stress and lead to extension of lifespan./nSirtuins have been shown to play a significant role in tissue maintenance by regulating cellular response to stresses such as genome instability, oxidative stress, and nutritional stress. However, since their role in maintaining proteostasis has not been studied yet, we set out to investigate if SIRT7, a nuclear member of the sirtuin family, functions in regulating protein homeostasis, particularly in the context of protein folding stress. Using a murine model, we focused on studying the function of SIRT7 in the liver and the hematopoietic system, two tissues that SIRT7 is most highly expressed in. We found that in the liver, SIRT7 relieves ER stress through suppressing translation by inhibiting the transcription of ribosomal proteins via Myc. In hematopoietic stem cells, SIRT7 regulates mitochondrial stress by repressing the activity of NRF-1 and inhibiting the transcription of mitochondrial ribosomal subunits. In a physiological context, loss of SIRT7 leads to a steatohepatitis phenotype in the liver and an aging phenotype in the hematopoietic stem cells. Thus, our study suggests the maintenance of stress by SIRT7 as an important mechanism for hepatic lipid metabolism and hematopoietic stem cell function.

Advisor: Chen, Danica
Making Translation Visible: Interpreters in European Literature and Film

This dissertation examines interpreter figures in European literature and film since the Second World War, from the implementation of simultaneous interpreting at the Nuremberg Trials to the growth of the European Union and the rise of a global information economy. I approach interpreting as an embodied act of translation, and the works I analyze explore the frictions that arise when an embodied subject is employed as a supposedly neutral medium of communication. In contrast to fantasies of instantaneous transfer and unlimited convertibility enabled by digital translation technologies, the interpreter’s corporeality attests to the material and culturally specific aspects of linguistic communication within larger processes of international exchange. Working against a tradition of effacement, I investigate aesthetic representations that render the interpreter’s body visible, audible, and even tangible, and thereby offer new possibilities for conceiving of translation as a multi-directional encounter rather than a form of hermeneutic extraction and transfer. This approach also highlights the gendered nature of interpreting as a form of intimate, affective service work, which is further figured in relation to traditional discourses of translators as potentially duplicitous women./nBoth Ingeborg Bachmann’s short story “Simultan” (1968/72) and Rainer Werner Fassbinder’s film Die Ehe der Maria Braun (1979) employ female interpreter figures to stage the ongoing relevance of Germany and Austria’s National Socialist past to the historical moments in which they originated. While the protagonist of “Simultan” experiences historical and linguistic fragmentation as an instrumentalized “language machine,” Maria Braun attempts to exercise agency through sexual, economic, and linguistic exchanges that are nonetheless constrained by larger social forces. In Yoko Tawada’s novella Das Bad (1989) and novel Das nackte Auge (2004), the dangers of translation as hermeneutic violence are inscribed upon female bodies, yet these bodies also hold the potential for alternative forms of translation as a shared experience of encounter. Finally, Hans-Christian Schmid’s film Lichter (2003) positions interpreters as key points of facilitation, friction, and intimate exchange within an unstable border zone.

Advisor: Göktürk, Deniz
The Role of Fire in California’s Landscapes Across Spatial and Temporal Scales

The role of fire in California’s landscapes has dramatically changed in recent centuries with the arrival of European cultures and later by the influence of rapid climate change. Novel challenges face land and fire management in the forms of invasive species, human encroachment, severe fuel loads, and fire regime shifts. Because fire is a critical land management tool and natural process in California ecosystems, reintroducing prescribed fire to our ecosystems is increasingly necessary, but also more challenging than ever. It is now of utmost importance that we investigate and seek to understand the modern role of fire in historic, modern, and future ecosystems at multiple scales./nFirst, I investigate the micro-scale effects of fire in an invaded ecosystem to elucidate how novel plant community dynamics in the face of fire. Studying fire-use related plant species interactions at the 1-m scale informs how we can expect plant communities to shift due to fire in the face of invasive species. This technique is a useful tool for managers and scientists to experiment with variations in fire-use to find ideal fire regimes in novel communities, and to prepare for fire-effects on plant communities./nSecond, I investigate prescribed fire effects across an invaded site of a similar plant community knowledge using information gained from these micro-scale investigations. Here I implement the knowledge gained from the micro-scale study, while incorporating more diverse investigations of fire effects, including soil nutrient and seedbank dynamics. This exploration allows for a more holistic understanding of fire-ecosystem interactions in these novel communities. The use of these intensive monitoring techniques on prescribed fire empower adaptive management by informing scientists and land managers of prescribed fire effects, and allowing for informed adjustments to practices based on results./nFinally, I study the role of fire at a much larger scale through an investigation of seasonal conifer xylogenesis. By better understanding annual cambial development of California’s common mixed conifers, we can more accurately interpret fire scars and, in turn, California’s fire history. We can then also use this information to look to the future and inform decisions regarding management of our landscapes and firescapes in the face of rapid climate change.

Advisor: Stephens, Scott L
Turbocharged Engine Control for Fuel Efficiency and Torque Responsiveness

Fuel economy standards for cars and other vehicles are growing increasingly stringent, thus motivating automakers to find ways to improve fuel efficiency. One popular strategy is to turbocharge a downsized (smaller displacement) engine, which can be more fuel efficient than a naturally aspirated engine delivering the same power output. However, turbocharged engines can be sluggish to respond to torque requests, which drivers often find undesirable. Unfortunately, improving torque responsiveness results in reduced fuel efficiency, and vice versa./nThis dissertation explores two model-based control strategies to manage this tradeoff. The first strategy is a decentralized controller, in which the throttle and wastegate are controlled in separate loops. The throttle loop uses feedback linearization with supplemental PI control to obtain good torque tracking. The wastegate is opened or closed, based on a preview of the reference torque, to switch between fuel-optimal and torque-optimal modes. The second strategy is a multi-objective optimization scheme to obtain good fuel efficiency and fast torque response by controlling the throttle and wastegate simultaneously. Simulation results show promising performance from both strategies./nAdditionally, the models used in these control methods are described in detail. A high-fidelity engine simulator in Simscape is used for controller validation. This simulator is too complex for controller design, so a simpler 4-state model is constructed. This model works well in continuous time, but the optimization-based control method requires a discrete-time model. Unfortunately, discretizing the 4-state model results in chattering due to numerical stiffness. This numerical stiffness is analyzed, and a solution is proposed to represent the throttle pressure ratio as a static map. This results in a 3-state model that is easily discretized.

Advisor: Tomizuka, Masayoshi
Synthesis of Complex Alkaloids Using New C–N bond Formation Methods

This dissertation describes our syntheses of natural product scaffolds and alkaloid natural products, with a focus on the development of new and interesting methods for carbon–nitrogen (C–N) bond formation. The first chapter discusses our synthesis of the pentacyclic core of arboflorine, a Kopsia indole alkaloid. Our synthetic sequence features the use of an efficient Heck coupling and a regioselective Ir-catalyzed C–H borylation to form a highly substituted methoxypicoline derivative and a convergent Suzuki–Miyaura cross coupling of a 2-bromo tryptamine derivative. For our key step in the synthesis, we report an unusual transannular, radical-mediated, dehydrogenative C(sp2)–N bond formation to furnish the pentacyclic core of arboflorine./nIn the second chapter, we discuss our formal syntheses of the poly-alkylated indole natural products, cis-trikentrin A and herbindole B. Given their modest complexity, these molecules have been the target of syntheses by numerous groups mainly to highlight new synthetic methods. We investigated a divergent approach, using a common meso hydroquinone intermediate. En route to synthesizing the target compounds, we discovered a new chemical transformation—using Pd-catalyzed C–H activation conditions developed by Jin-Quan Yu and co-workers, we were able to transform an ortho-ethyl aniline to the corresponding indole in one step. This bond formation method allowed us to exploit the pseudo-symmetry of the target compounds by using a symmetrical hydroquinone precursor./nIn the third chapter, we investigate the possibility of making our syntheses of cis-trikentrin A and herbindole B enantioselective. We explored methods of asymmetric desymmetrization of the meso hydroquinone intermediate used for both syntheses. These methods were explored in collaboration with different people and groups including Dr. Caroline Bischof from our lab, Dr. Ana Hurtley from Prof. Scott Miller’s lab at Yale University, and Luke Latimer and Zachary Russ from Prof. John Dueber’s lab in the Department of Bioengineering at UC Berkeley.

Advisor: Sarpong, Richmond