VictorJuiz/thesis huggingface dataset:
Heartbroken : democratic emotions, political subjectivity, and the unravelling of the Weimar Republic, 1918-1933
Keywords: History.

This dissertation investigates how German intellectuals, activists, and elected officials wrestled with the relationship between emotions and democracy during the years of the Weimar Republic (1918--1933), Germany's tumultuous first democratic experiment. It upends long-held historiographical assumptions about the sober rationality of Weimar republicans, unearthing rather the startling extent to which Germans both imagined and cultivated particularly democratic feelings in the years after the First World War: erotic desire and neighborly love, nostalgia and solidarity and belonging and righteous anger. This dissertation both charts the emergence of this passionate democratic style and tells an unsettling story about how and why it finally vanished. The following dissertation argues that while this renunciation was not inevitable, it is does help to explain how Germany's interwar democratic culture came to be so brittle. In this way, the dissertation offers an alternative explanation for the unravelling of Weimar democracy in the early 1930s. Most broadly, by tracing shifting ideas about democratic emotions and human nature, this dissertation offers European historians as well as scholars of democracy a novel way of approaching the success and failure of modern democratic states.
A heuristic for varying design parametrization applied to a multidisciplinary rotorcraft problem [electronic resource]
Keywords: Aeronautics and Astronautics.

At the aircraft conceptual design stage the potential design space is extremely large and the selection of the right set of design variables can be critical to finding a design optimum of practical value. This selection problem is particularly challenging for the human designer when the space not well understood. A means to improve the parametrization automatically as design and optimization proceeds with a heuristic approach to parametrization discovery is described in this dissertation. The heuristic applies important principles of evolutionary theory including: mutation, competition, and selection in searching for a better parametrization. The principles of parsimony in conjunction with variation in mutation probability are shown to to be important in ensuring efficient use of the degrees of freedom in an optimization problem. These prevent the parametrization size from tending toward infinity over successive generations while still finding better objective function values. Starting from simple geometry matching problems, with well defined objectives, and working up to complex multidisciplinary rotorcraft vehicle design problems, the heuristic is shown to have an ability to discover parametrizations which lead to improved objective function values compared to what can be achieved with the initial parametrization. A set of necessary methods are also developed to enable higher-fidelity analysis of rotorcraft designs earlier in the design process, when coupled with the parametrization discovery heuristic.
Hidden Injuries: The Challenges of Preventing Fatalities in Horse Racing
Keywords:  Department of Communication
horses
horse racing
thoroughbreds
California Horse Racing Board
fetlock
horse injuries
Golden Gate Fields
Thesis

There is no easy or reliable method to identify microscopic injuries in horses that can lead to catastrophic breakdowns while racing. In an attempt to prevent as many fatalities as possible, at Golden Gate Fields in Albany, California, veterinarians inspect horses before and after every race. But despite best efforts, some horses that pass the medical examination and show no external signs of injury or lameness will still suffer fatal injuries.
Although it is impossible to prevent all fatalities in horse racing, California has lowered the fatality rate in recent years. There have been extensive efforts to ensure that race horses have a high quality of life during and after their racing career.
High performance cloud computing
Keywords: Electrical Engineering.

Running fast computations at a large scale increasingly stresses task scheduling performance. As CPU performance becomes the performance bottleneck, it is common to optimize CPU performance, further parallelize computations by using more nodes, and split computations into more finely-grained tasks. As a result, a cloud framework running an application on thousands of cores must schedule hundreds of thousands of tasks per second. A framework must be also able to dynamically reschedule tasks in order to achieve high CPU utilization in the presence of an unbalanced load, stragglers, and node failures. Today, systems must choose either high task throughput or dynamic, centralized scheduling: no existing system can provide both. This dissertation proposes a data-centric asynchronous control plane, which schedules hundreds of thousands of tasks per second while retaining a central interface to dynamically reschedule tasks. In this design, a central controller decides how to redistribute work, but workers locally decide between themselves when to redistribute. The controller avoids issuing per-task scheduling decisions by using data placement as the control signal for load distribution. So this design provides a declarative, central, and asynchronous load control mechanism without limiting task throughput. This control plane depends on a new program abstraction, called task recipes, that enables workers to locally schedule tasks and asynchronously migrate data and computation. This dissertation implements the design in a from-scratch in-memory cloud framework called Canary and evaluates its performance on data analytics and machine learning benchmarks. Furthermore, this dissertation examines how applications benefit from the design by using fluid simulation as a case study, and it proposes a new load-balancing algorithm in this context.
High resolution photovoltaic retinal prosthesis with three-dimensional neural interface [electronic resource]
Keywords: Electrical Engineering.

The number of electronic implants for restoration of various neural functions is rapidly growing. They include such highly successful systems as cochlear implants for restoration of hearing and deep brain stimulators for reducing the symptoms of Parkinson's disease. Retinal degenerative diseases lead to loss of photoreceptors, while neurons in the inner retinal layers are largely preserved. Retinal prostheses seek to restore sight by reintroducing visual information via electrical stimulation of the surviving neurons in the retina. Most retinal prostheses are powered through inductive coils, requiring complex surgery. At Stanford, our group developed a photovoltaic approach to retinal prosthetics, where silicon photodiodes in each pixel of the sub-retinal array convert pulsed near-infrared illumination projected from video goggles into an electric current to stimulate the nearby neurons. This work presents the design and fabrication process of the implantable photovoltaic arrays, and demonstrates their performance in vitro, as well as the results of preclinical testing in vivo. In particular, we have shown that spatial resolution of prosthetic vision with 70 um pixels in rodents is limited by the pixel pitch, and stimulation thresholds are much lower than the ocular safety limits. Based on this success, we developed a new process that enabled fabrication of pixels as small as 40 um in size. To improve proximity between the electrodes and neurons, we developed three-dimensional pillar electrodes, and found their optimal height for integration with the retina during chronic implantation. We also developed a fabrication process for incorporating these pillar electrodes into photovoltaic arrays. During early in vivo experiments, we observed significant degradation of the retinal implants. To prevent this, we developed a process of using a plasma-enhanced chemical vapor deposited SiC films compatible with the rest of the photovoltaic array fabrication. This coating exhibited excellent stability during accelerated aging tests in vitro as well as during chronic implantation in vivo. The final chapter of this thesis provides outlook toward future directions for advancement and testing of this novel retinal prosthetic technology.
High temperature and transient behavior of GaN heterostructure based high electron mobility micro-pressure sensors [electronic resource]
Keywords: Mechanical Engineering.

Gallium nitride (GaN) is a wide bandgap semiconductor that is a promising material platform to build sensors and electronics for operation in harsh environments (e.g., Venus). AlGaN/GaN and InAlN/GaN heterostructures are leveraged to build transistors by utilizing a highly conductive sheet of electrons that forms at the interface of these materials, known as a 2-dimensional electron gas (2DEG). A piezoelectric polarization at the interface of GaN and AlGaN or InAlN are partially responsible for the 2DEG, and also enable strain and pressure sensing. The goal of this work was to design, microfabricate and characterize a temperature-tolerant, pressure sensor to support sensing in high temperature environments. This work characterized the pressure response of an InAlN/GaN micro-pressure sensor from 0 to 28.5 psig and the temperature response of solid state and released device up to 550°C. While InAlN/GaN and AlGaN/GaN devices show promise for high temperature pressure sensing, challenges around repeatability also need to be addressed. In order to understand the temperature dependence of the pressure sensitivity and transient device response, electronic traps are characterized in an AlGaN/GaN device between room temperature and 200°C.
High-efficiency ultrathin crystalline silicon solar cells
Keywords: Materials Science and Engineering.

The climate change associated with burning fossil fuels as dominant energy resource has been a significant concern. Solar photovoltaics (PV) is the dominant type of renewable and eco-friendly energy resource to alleviate this problem. Crystalline silicon (c-Si) PV has been the dominant type of solar cell with more than 90% of the global PV market at the end of 2017, because of its low-cost, good stability and well-developed processing technology. To continue reducing the price of solar modules, ultrathin c-Si solar cells have been investigated: they are a feasible pathway to continue "price scaling" by effectively reducing the c-Si material consumption. However, the performance of ultrathin c-Si cells is constrained by two physical limitations: poor light absorption and contact recombination. To achieve the optimal efficiency from ultrathin c-Si cells, the cells must be designed to overcome these limitations. This dissertation provides comprehensive experimental strategies to overcome these two performance limitations of ultrathin c-Si solar cells. The main part of this dissertation concludes with the characterization of the "free-standing", ultrathin c-Si cell integrated with carrier-selective contacts and light trapping structures. These cells show very consistent performance before and after being released from the substrate. These findings show the capability of ultrathin c-Si technology to not only reduce the material cost, but also maintain high efficiency.
High-energy gamma-ray observations of solar flares with the Fermi large area telescope
Keywords: Physics.

Solar flares are the most energetic events in our Solar System. They consist of sudden energy release from reconfiguration of magnetic fields, leading to acceleration of particles to relativistic energies. The Fermi Large Area Telescope (LAT) gamma-ray observations of the Sun present a unique opportunity to explore the mechanisms of high-energy emission as well as particle acceleration and transport in solar flares. I will present the results of the first 9 years of observations of the active Sun by the Fermi-LAT, which represents the largest sample to date of detected solar flares with emission greater than 30 MeV. Some of the new detections confirm the standard models for solar flares based on observations from past missions in the 1980s and 90s, but new behaviors have also been identified: detections of delayed gamma-ray emission lasting up to 20 hours and the first detection of gamma-ray emission above 100 MeV from three solar flares originating from behind the visible part of the Sun. Considering all of the 46 flares detected by the Fermi-LAT, I will describe the characteristics of the first gamma-ray solar flare catalog covering Solar Cycle 24, exploring trends and correlations with the most relevant solar events: X-ray emission, coronal mass ejections, and direct detection of solar energetic particles.
Higher-genus wall-crossing in Landau-Ginzburg theory
Keywords: Mathematics.

For a Fermat quasi-homogeneous polynomial, we study the associated weighted Fan--Jarvis--Ruan--Witten theory with narrow insertions. We prove a wall-crossing formula in all genera via localization on a master space, which is constructed by introducing an additional tangent vector to the moduli problem. This is a Landau--Ginzburg theory analogue of the higher-genus quasi-map wall-crossing formula proved by Ciocan-Fontanine and Kim. It generalizes the genus-
High-performance antimonide p-MOSFETs and their hetero-integration on silicon
Keywords: Electrical Engineering.

As the benefits from scaling conventional silicon transistors start to saturate, newer structures such as gate-all-around or nanowire devices and alternate high-mobility channel materials such as III-V compound semiconductors can provide a much-needed boost to transistor performance. Antimonides are a promising group of III-V compound semiconductors being actively researched for high-speed low-power digital CMOS as well as for THz/mm wave device applications. They have the highest electron and hole mobility among all III-Vs and could potentially enable an all-antimonide CMOS solution. Antimonides are also the only viable candidate for a high-performance III-V p-MOSFET. This thesis first addresses the most critical challenge of III-V technology -- hetero-integration on a silicon substrate. The rapid-melt-growth (RMG) technique for the hetero-integration of GaSb on silicon is studied in detail, focusing on understanding the impact of film stoichiometry, purity and morphology. A low-temperature molecular beam epitaxy (MBE) process is developed to obtain pure, amorphous GaSb which is then melt-regrown into scaled high-quality single-crystal fins down to 130nm fin width. GaSb-on-insulator p-MOSFETs are successfully demonstrated and factors limiting device performance are identified. In parallel, quantum-well heterostructures were grown by the more established technique of metamorphic buffer growth to obtain high-performance InGaSb p-MOSFETs. Two different device structures are compared -- a buried channel structure and a surface channel structure. Scaled devices with ~100 nm gate length metal gate/high-κ dielectric and self-aligned Ni-alloy metal source/drain are demonstrated. Finally, the first set of studies to investigate the radiation response of antimonide p-MOSFETs for potential use in harsh environments such as space and defense applications is conducted. Laser and heavy-ion irradiation testing is performed and supported with simulations to understand the basic mechanisms of single-event-effects in these heterostructure antimonide p-MOSFETs.
A high-throughput screening method for engineering proteolytically stabilized growth factors
Keywords: Bioengineering.

Growth factors are an important class of proteins that play a pivotal role in orchestrating many complex biological processes such as wound healing, tissue regeneration, vascularization, and tumor formation. Thus, there is immense interest in utilizing growth factors as protein therapeutics. However, although numerous recombinant growth factors have been developed as therapeutic candidates, only a few have been effective enough to receive clinical approval. This is due, in large part, to their generally poor stability. Therapeutic growth factors must remain active for an extended period to be efficacious. However, growth factors can become degraded upon exposure to enzymes known as proteases. A growth factor's susceptibility to proteases can be particularly important because these enzymes are especially active in areas relevant for disease treatment. Growth factors have previously been modified to improve their proteolytic stability, and this has been shown to enhance their biological activity. However, current methods of engineering growth factors for increased proteolytic stability are limited by low-throughput and the lack of generalizable strategies that can be used in a consistently successful manner. Thus, it can be a difficult and slow process to generate new growth factor variants with improved stability. In this work, we describe the development of a high-throughput screening method for engineering proteolytically stabilized growth factors. We validate the ability of the screen to differentiate between proteins of different proteolytic stabilities. Then, we utilize the screen to engineer a proteolytically stabilized variant of fibroblast growth factor 1 (FGF1). Finally, we characterize the ability of the engineered FGF1 protein to resist degradation, and show that this variant surprisingly antagonizes the FGFR cell signaling pathway, which may have therapeutic implications for the treatment of ocular neovascularization and tumor formation.
History Matching Production and Displacement Data Using Derivative-free Optimization
Keywords:  Department of Energy Resources Engineering
School of Earth Energy &amp; Environmental Sciences
[History Matching
Geomechanics
Derivative-free Optimization]
Thesis

Geomechanical simulators can be used to predict production-induced subsidence. However, the uncertainty in these predictions depends on the uncertainty in the flow and geomechanical parameters, such as permeability and Young's modulus. In this thesis, we develop a derivative-free optimization procedure for calibrating flow and geomechanical parameters. The method entails the use of the iteratively coupled flow-geomechanics module in Stanford's Automatic Differentiation General Purpose Research Simulator (AD-GPRS) combined with the mesh adaptive direct search (MADS) optimizer. Multiple sets of history matched parameters are generated using the randomized maximum likelihood (RML) procedure.
Both production and displacement (geomechanical) data can be assimilated within our framework. Data types considered in this work include well production data, surface displacement data and well displacement data, and the impact of these different types of data on predictions and parameter calibration is assessed. We first consider a three-layer model with no overburden rock. For this case, we show that assimilating either type of displacement data is useful for calibrating the harmonic average Young's modulus as well as permeability in each layer. Assimilation of either type of displacement data reduces uncertainty in both surface displacement and production predictions. Assimilation of production data, by contrast, improves permeability calibration and reduces uncertainty in production forecasts, but not in displacement predictions. We also show that history matching surface displacement data does not provide calibration of individual layer Young's moduli, though it does enable accurate calibration of the harmonic average Young's modulus over all layers. History matching well displacement data provides calibration of individual layer Young's moduli.
We next consider a more realistic (though two-dimensional) geomechanical model that includes overburden rock and bedrock. For this case we again demonstrate that both surface and well displacement data are useful for reducing uncertainty in surface displacement predictions and for estimating the harmonic average Young's modulus over all reservoir layers. Well displacement data are shown to again enable the calibration of individual layer Young's moduli.
Holocene climate change from Fjord and Lake Sediment core and seismic records in Southern Patagonia
Keywords: Environmental Earth System Science

The Southern Hemisphere westerly wind field modulates Earth's climate by regulating Southern Ocean CO2 ventilation through wind-induced upwelling of Circumpolar Deep Water. However, past changes in the southern westerlies and the extent to which the westerlies influence global atmospheric CO2 concentrations remain relatively unknown. Southern Patagonia, the only major landmass extending into the core of the wind field, is an ideal location for reconstructing past changes in the westerlies. In Chapters 1 and 2, we present the results of sediment cores collected from Lago Sarmiento (51˚S), a large, closed-basin lake, and from Golfo Almirante Montt (GAM; 52˚S), an isolation basin in the Chilean inner-fjord system. We investigate changes in precipitation, relative westerly wind intensity, and Neoglacial events over the last 11 ka using core sedimentology, stable isotope (δ18O, δ13C and δ15N), weight percent carbonate, and elemental concentration (C & N) data. In Chapter 3, we present results of a high resolution seismic survey in GAM. Sediment core data from Lago Sarmiento and GAM identify: (1) low precipitation and weak westerlies during the early Holocene (11 -- 9.6 ka), (2) maximum Holocene precipitation and westerly wind strength in the Mid-Holocene (5.4 -- 4.1 ka), (3) low precipitation and weakening westerlies between 3.4 -- 1.5 ka, (4) and two significant regional Neoglacial events between 9.6 -- 9.0 ka and 4.1 -- 3.4 ka; we interpret Neoglacial events as a strong pulse of precipitation and strengthening of the westerlies over our field site. Our seismic survey in GAM reveals a sedimentary basin that exceeds a thickness of 100 m. We identify three seismic-stratigraphic facies, which we interpret as: (1) rapidly deposited glacio-lacustrine sediments, (2) outwash as a result of catastrophic ice-dam failure at the termination of the Last Glacial Maximum, and (3) Holocene ice-distal glacio-marine sediment. These data provide important insights into Southern Hemisphere Late Quaternary climatic variability.
Hot-electron devices and physics based on oxide heterostructures
Keywords: Electrical Engineering.

Today, we live in the age of nanomaterials with discovery of novel properties at nanometer length scales. In this thesis, we focus on perovskite oxides at such length scales in the form of thin films and heterostructures, which represent rapidly emerging class of nanomaterials significant for a rich variety of emergent phenomena. Until now, research has mostly focused on using easily accessible in-plane experimental probes to study these systems. The goal of this thesis is to expand upon this approach by establishing a solid vertical device platform and to probe the dynamics of the strongly correlated electron systems therein. As part of this goal, we focus on the fabrication of vertical hot-electron transistors based on oxide heterostructures down to the two-dimensional limit with atomic-scale precision and then the study of non-equilibrium dynamics of hot electrons across phase transitions using these device platforms. Further, we probe the spectroscopic evolution of hot-electron dynamics in oxide heterostructures using internal photoemission spectroscopy. These studies open up new avenues for probing and utilizing emergent phenomena at oxide interfaces and heterostructures using vertical device geometry.