VictorJuiz/thesis huggingface dataset:
On the threshing floor : roadblocks and the policing of everyday life in Zimbabwe
Keywords: Anthropology.

Between 2012 and 2017, the Zimbabwean government dispatched police officers to mount roadblocks on the country's major roads and many of the minor ones. What had once been a ten-minute drive to work or to drop children off at school could now become an hour-long series of negotiations with the police officers who manned the roadblocks, in a country with no militias and no armed conflict. This dissertation presents a close examination of encounters at the roadblocks. Taking roadblocks as a key site of citizen/state engagement in the crisis era, it asks how people's conceptions of mobility, of governance, and of citizenship are expressed and transformed in the face of unrelenting policing. Emerging in the wake of staggering economic and sociopolitical crisis, roadblocks are central the state's performance of itself as such. Yet, as police and policed come together to negotiate the rituals of inspection, forms of sociality arise at the roadblock that prompt a different kind of understanding of citizenship, and challenge neat distinctions between police and policed. The dissertation is based on 21 months of ethnographic fieldwork I conducted in Zimbabwe - on the road, driving around in combis, buses, cars and trucks with motorists while they were stopped and inspected - as well as at police stations, government buildings, and other spaces in which the terms of everyday life are negotiated.
Online sellers' offline environment : implications for platform strategy
Keywords: Management Science and Engineering.

How does a seller's local environment affect their behavior on digital platforms? The digitization of the economy has drastically lowered the costs of data storage, access, and transmission. Leveraging digital technologies, platform companies such as Amazon and Airbnb have created online marketplaces that have extended an unprecedented level of market access to individual entrepreneurs, whom we often refer to as sellers. Much of the existing research on digital platforms shows that platforms can dictate sellers' behavior through a variety of reward and punishment mechanisms, e.g., search ranking algorithms and surge pricing. However, a great amount of variation in sellers' behavior can be attributed to factors in their local environment -- factors outside the platform's control. Upon closer examination, one may realize that local factors could potentially explain many perplexing seller actions faced by platforms and their engineers. For instance, why do Uber drivers protest surge pricing? Why do e-commerce sellers continue to sell counterfeit products despite strict regulation? Why do Airbnb hosts refuse to interact with users even with algorithms rewarding host-user interactions? In this dissertation, I argue that factors such as sellers' cultural customs, local interactions, and perception of the law may serve to explain many of their behavioral patterns. These factors strongly affect sellers' behavior on digital platforms. Their behavior, in turn, influences a platform's growth trajectory and contains major social implications. Therefore, it is important for both platform designers and policymakers to pay attention to sellers' heterogeneous local environments in order to anticipate sellers' behavior, create appropriate designs, and devise sound policy.
Optical Kerr effect studies of hydrogen bonding and phase behavior in aqueous binary mixtures
Keywords: Chemistry.

The behavior of molecules in condensed phases involves complex considerations to fully describe the microscopic structure and dynamics. This is particularly interesting in complex liquids with inherent heterogeneity and in binary mixtures where the competition between the interactions between similar and dissimilar species greatly affects the microstructures of the liquid. The ubiquity of aqueous binary mixtures necessitates their study, particularly because the unique properties of water often manifests anomalously in the physical properties of binary mixtures. These changes in physical properties are the result of structural changes at the molecular level. In this thesis, the dynamical results from optical heterodyne-detected optical Kerr effect (OHD-OKE) experiments are reported for a series of aqueous binary mixtures. OHD-OKE is a nonresonant pump probe technique in which the bulk orientational dynamics of a liquid are measured via the time-dependent birefringence induced in the sample by an optical pulse. The OHD-OKE setup used in this thesis has the ability to measure dynamics over seven decades of time and eight decades of signal, which is an incredible window for a single experimental technique. Ultrafast pulses, which are necessary to have sufficient resolution, are generated by a Ti:Sapphire oscillator/regenerative amplifier. Multiple techniques including heterodyne detection and phase cycling are used to improve signal to noise, particularly at long time when signals are small. The theory behind OHD-OKE and a description of the experimental setup are given here. In addition to dynamical information, microstructural changes can be extracted from OHD-OKE data using the Debye Stokes Einstein (DSE) equation. The specific structures can be elucidated using complementary techniques. The remainder of the thesis is devoted to the aqueous binary mixtures of interest and the results from OHD-OKE and complementary techniques. First, a protic ionic liquid is compared to its aprotic analogue in order to better understand the role of hydrogen bonding in ionic liquids at various hydration levels. This work is further expanded to ionic liquids of varying chain lengths and anions in order to provide a deeper understanding of hydrophilicity and water saturation in ionic liquids. Finally, the anomalous phase behavior of the nicotine/water binary system is studied in order to elucidate the dynamics and microstructures associated with the lower critical solution temperature.
Optimization of CO2 Storage Systems with Constrained Bottom-Hole Pressure Injection
Keywords:  Energy Resources Engineering
School of Earth Energy &amp; Environmental Sciences
Optimization
CO2 Storage
CCS
Thesis

Of concern with CO2 storage in underground aquifers is the potential leakage of mobile CO2 into the regions above or surrounding the storage site. In this study, we perform an optimization study to minimize the mass of mobile CO2 at the top of the formation at the end of a typical CO2 storage project. We define and solve a comprehensive optimization problem involving well placement and control, along with appropriate constraints. The computations are performed within Stanford's Unified Optimization Framework.
We consider two different storage aquifer models - a channelized aquifer and an aquifer characterized by multi-Gaussian statistics. For both models, we perform a heuristic sensitivity study to estimate the required pore volume of the region surrounding the storage aquifer such that the bottom-hole pressure constraint is not violated. We consider different injection scenarios by varying the number of CO2 injection wells. Optimizations are performed using a combination of particle swarm optimization (PSO) and mesh adaptive direct search (MADS). Multiple runs are conducted to account for the stochastic nature of the optimizations. The sensitivity of the optimized objective to the number of injection wells is assessed for both models. We observe a 45% decrease in the objective function value as the number of wells is increased from one to four for the channelized aquifer model. For the Gaussian model, the corresponding decrease in the objective function value is 33%. We also perform a study to determine the minimum pore volume of the surrounding region that allows for a feasible injection strategy (in terms of maximum bottom-hole pressure), for each of the injection scenarios in both of the aquifer models. We observe that with four injection wells, a surrounding region of pore volume 17 times that of the storage aquifer is required for the channelized model, and 10 times that of the storage aquifer is required for the Gaussian model.
Organothiol manipulation of copper for advanced electronics [electronic resource]
Keywords: Materials Science and Engineering.

Organothiol manipulation of inorganic conductive materials like copper provides a powerful synthetic route towards low-dimensional technologically important materials with atomically well-defined structures. Two examples from my research are presented in this thesis dissertation to demonstrate how organothiol chemistry can be leveraged to manipulate copper for a two-dimensional (2D) interface and for a one-dimensional (1D) nanowire construct for advanced electronics. In the first example, the application of a hybrid layer containing organothiol at a 2D copper surface is demonstrated in which the hybrid layer manipulates the surface copper-oxide. The presence of defective copper-oxide remains a challenge for device technologies owing to its detrimental effects on the adhesion and stress-migration. Here we show a rapid, single-step, and organic-solvent-free thin-film deposition process that is capable of simultaneously reducing the weak copper-oxide while forming a densely connected copper/hybrid interface. A marked 9-fold improvement in interfacial adhesion is reported, along with a substantially suppressed copper stress-migration behavior during in-situ isothermal stress-relaxation experiments. The enhanced copper/hybrid interfacial adhesion and the improved copper stress-migration performance are attributed to the partial reduction of the ∼2 nm native Cu2O layer as demonstrated via atomic-resolution transmission electron microscopy. The hybrid-layer strategy we developed is expected to be effective in not only being a promising candidate for adhesion improvement to copper, but in promoting copper stress- and the related electro-migration performance. In the second example, I demonstrate the synthesis of 1D core-shell nanowires that have electrically conductive inorganic cores and insulating organic shells. Core-shell nanowires are synthesized via a facile solution process, leveraging the strong chemical interaction between organothiol molecular precursors and copper. Electronic properties of nanowires are characterized via electrochemical impedance spectroscopy, and elemental compositions are determined via x-ray photoelectron spectroscopy. Atomic arrangements inside the core-shell nanowires are unraveled via high-resolution x-ray diffraction in conjunction with molecular dynamic and density functional theory computations. Transmission electron microscopy provides a glimpse into the core-shell nanowire structure. We demonstrate, via this combinatorial approach, the exact atomic arrangement inside ultrathin nanowires comprising of only 5 inorganic atoms in the cross-section. The nanowires' unique electronic properties and our complete understanding of their atomically well-defined structures make them promising candidates for use in the next generation advanced electronics which are constantly seeking conductive features of diminishingly small size.
Overcoming challenges to incorporation of inertial sensors in an epitaxial encapsulation process
Keywords: Mechanical Engineering.

This work presents a deep investigation of one of the primary challenges to fabricating high performance inertial sensors - stiction. We begin with a summary of what stiction is, and a review of some of the past work understanding this problem and ways to over come it. We continue with a discussion of how the problem manifests itself in the Stanford Epi-Seal process, and the particular considerations of this problem. Our work begins with an experimental investigation of the process and in-use stiction problems in our devices. We develop design guidelines to assist future designers based upon the results of the experiments. Furthermore, we investigate the causes of stiction, and suggest ways in which the baseline process stiction may be improved in future work. A result of this investigation is a more formal understanding of stiction, and a reliable set of test structures and processes. We utilize the methodologies developed in the first experimental section, along with the test procedures to develop anti-stiction solutions. We first examine the common anti-stiction solutions, and determine that they are not applicable to the epi-seal process. Instead we thoroughly investigate mechanical structures which help dramatically reduce the stiction. We also develop models of the device behavior and adhesion which help us extend our understanding of stiction and make predictive assessments in the future. The epi-seal process presents an interesting platform for harsh environment devices. We examine the behavior of the principal failure mode (stiction) at high temperatures and under high-g shock inertial impacts. We demonstrate the suitability of the devices, and investigate some surprising results that emerge. We also investigate some other device parameters under these conditions. Lastly, we describe some of the high-speed, time-domain measurement systems used to collect the data used throughout this work. We briefly discuss the operational principle of several typical MEMS characterization tools, and outline the benefits and limitations. We compare these to data analysis techniques in the time domain, and show how many of the same techniques are used, but with different constraints.
Overexpression of Thioredoxin-2 to Prevent Ventilator-Induced Diaphragm Dysfunction
Keywords:  Department of Biology
Molecular Biology
Mechanical Ventilation
Antioxidants
Thesis

Mechanical Ventilation (MV) is a life saving measure routinely used in intensive care units for patients incapable of independently breathing. Ventilators function by pumping air and oxygen into patients’ lungs, taking over the function of the major respiratory muscle, the diaphragm. Because the machine does the mechanical work of breathing, the diaphragm is placed at rest. This “disuse” causes the diaphragm to lose a significant amount of contractile force after only 12 hours of MV, leading to a clinical condition called ventilation-induced diaphragm dysfunction (VIDD) [1]. VIDD often leads to prolonged ventilator dependence, which is closely associated with the occurrence of numerous clinical complications such as pneumonia and ultimately increases mortality in patients with prolonged ventilation [1]. Some of the molecular pathways underlying MV-induced diaphragm dysfunction have been elucidated; oxidative stress is believed to be one of the most important pathways [2]. Reducing oxidative stress with, e.g., use of an antioxidant, is thus a potential therapeutic approach to prevent VIDD and thus reduce ventilator dependence in patients. Thioredoxin-2 (TRX2) is a gene that encodes a mitochondrial-resident antioxidant protein, Trx2. Trx2 regulates redox homeostasis by reducing the levels of H2O2, thus preventing oxidative damage to cellular proteins and reducing cell death [3]. Trx2 has already been shown to provide protection against oxidative stress-induced damage in mouse heart muscle [2,3]. I hypothesized that transgenic mice overexpressing Trx2 protein would be able to overcome MV-induced oxidative stress and that they thereby would not develop, or develop less severe, VIDD. This hypothesis was tested by performing 12-hour MV in both wild type (WT) and TRX2-trangenic mice, immediately followed by isometric contractile force measurements of the diaphragm muscle to assess Trx2’s effect on diagram muscle contractility. With the limited number of mice available, much of the data failed to reach significance; however, we did see an increase in force generation by the ventilated TRX2 mouse diaphragms compared to ventilated WT mouse diaphragms. This data justifies further investigation to verify if TRX2 mice are, in fact, protected from the ventilation-associated reduction in contractile force, and how Trx2 might be delivered exogenously as a potential therapy for ventilator-induced diaphragm dysfunction.
Passivation of the negative electrode in lithium-ion batteries : lithium fluoride in the solid-electrolyte interphase
Keywords: Chemistry.

Lithium-ion batteries have become the standard in rechargeable batteries for both portable electronics and electric vehicles because of their high energy and power densities. The solid-electrolyte interphase (SEI) on the negative electrode of these batteries is critical for their performance: it must allow lithium ions to pass while providing a barrier between other reducible species in the electrolyte and the highly reducing electrode, while maintaining the conduction of lithium ions necessary for battery operation. However, in commercial battery production it is often left to form adventitiously on the battery's first charge, optimizing the charging conditions rather than the chemical identity of the layer. As a result these SEIs consist of a complex mixture of organic and inorganic reduction products, a large part of which cannot fulfill the main three functions of an SEI: (1) electronic insulation, (2) impermeability to solvent and electrolyte species, and (3) lithium-ion conductivity. In this thesis it is shown that a simplified SEI primarily composed of lithium fluoride (LiF) can perform these functions, mimicking the beneficial function of an SEI. Furthermore it is shown that LiF can efficiently be deposited by the electrochemical reduction of hydrogen fluoride (HF), small quantities of which are known to be present in battery electrolytes due to hydrolysis of the electrolyte salt lithium hexafluorophosphate. The deposition of this thin layer is characterized and optimized using a simplified electrolyte chemistry on metallic electrodes. 19F-Nuclear magnetic resonance (NMR) spectroscopy is introduced as a useful tool for studying the production of HF in LiPF6-containing electrolytes. Using NMR it is shown that the hydrolysis reaction is strongly dependent on the ion pairing, and that it is greatly slowed in the absence of the lithium ion. The NMR signal for HF is studied in detail, and the expected H-F coupling is observed at low concentrations in the absence of water. A facile way to precisely control the concentration of HF in non-aqueous lithium-ion battery electrolytes containing lithium hexafluorophosphate is presented and benchmarked. The effective removal of adventitiously formed HF in these electrolytes by 3-A molecular sieves is demonstrated, which enables an HF-free LiPF6-based electrolyte for the first time. Subsequently the synthesis, drying, and quantification of anhydrous hydrogen fluoride in non-aqueous solvents was developed and characterized, yielding precise control over the concentration of HF and the following electrodeposition of LiF. Using these techniques the electrodeposition of LiF can be finely controlled. The resulting thin layer can fulfill the main functions of the SEI without excess loss of lithium, clearing the way for more efficient SEI formation in commercial lithium-ion batteries.
Passive seismic imaging of the Ruby Mountains metamorphic core complex
Keywords: Geophysics.

In this dissertation I present new results from passive seismology of the Ruby Mountains metamorphic core complex in northeastern Nevada. For this project I installed a 50-station temporary broadband seismic network over the Ruby Mountains—the first seismic study to image directly beneath the mountains. I use ambient noise tomography to build a velocity model of the region and delineate basin locations surrounding the mountains. Then I employ common conversion point stacking of receiver functions to image the deep crustal structure of the core complex. I observe a Moho depth of ~32 km throughout most of the study region, but reaching ~42 km depth in a narrow N-S welt 20-50 km west of the Ruby Mountains. Shear wave splitting results also show a change in fast polarization direction at this location. Finally, I examine the records of local mine blasts that are routinely detonated in the region as an additional check of the regional seismic velocity, as well as potentially to provide an additional estimate of Moho depth. I combine my observations with previous geologic and geophysical studies to suggest that the formation of the Ruby Mountains may have involved asymmetric crustal flow at the edge of a preexisting orogenic plateau.
Paths to exclusion : deportations, housing instability, and scams
Keywords: Sociology.

How have immigrant communities adapted to mass deportations? My dissertation examines the demographic determinants of deportation activity as well as the consequences of mass deportations for noncitizens. I find deportations disrupt residential and territorial membership via worsening housing instability and fewer than expected crime reports. Civil society can buffer noncitizens from the negative consequences of arrests and scams, but collateral damage from deportations can erode networks of social capital. Protection from the harm of deportations also proves weakest precisely in locations -- such as new immigrant destinations -- which can least afford to absorb the disruptions associated with mass deportations. The long-term consequences of weakened social capital are not contained to noncitizen households. Broader U.S. society suffers when paths to exclusion destabilize households and challenge trust in law enforcement and the legitimacy of public institutions.
Paul Thek : untimely bodies, 1963-1988
Keywords: Art and Art History.

This dissertation examines the work of the American artist Paul Thek (1933-1988), an important but nearly forgotten figure of the 1960s art world. Framed by the concept of 'untimeliness', it addresses Thek's disappearance from the dominant narratives of postwar modernism, examining his absence in light of an early and anachronistic commitment to sculptural figuration (or "disfiguration"), as well as the critical re-appraisal of his work after his death from AIDS-related complications. The dissertation brings Thek's repulsive, disfiguring sculptures of meat of the 1960s, his pioneering installation art of the 1970s and 1980s, and the painterly practice he maintained throughout his career into dialogue with close readings of the voluminous body of writing contained in nearly one hundred of the artist's extant notebooks. Thek's oeuvre becomes a prism through which to re-assess the formation of art history itself while raising important questions of phenomenology, technology, and materiality in post-1960s aesthetic practice in America and Europe vis-à-vis issues of national belonging, religiosity, queer sexuality, and the body.