VictorJuiz/thesis huggingface dataset:
Dynamics of miscible liquid interfaces

This thesis is comprised of three parts, focusing on the dynamics of miscible liquid interfaces, the dynamics of ultra-low surface tension liquid interfaces, and the spreading of "rinsing" liquids across rotating, horizontal substrates. Miscible liquids commonly contact one another in natural and technological situations, often as one liquid suspended within another or in the proximity of a solid substrate. A systematic experimental study of the shape evolution of pendant and sessile droplets immersed in miscible environments was conducted. We present experimental findings that have distinctly different shape evolution and time-dependent dynamics from droplets present in immiscible environments, which have been reported previously. A complementary numerical approach to compute the concentration and velocity fields of these systems using a simplified set of governing equations is paired with our experimental findings. Additionally, a study of droplets freely rising through a miscible, more viscous liquid was conducted. We report observations of droplets of water rising through glycerol and corn syrup. A class of ultra-low surface tension liquids are aqueous two-phase solutions, which form by the phase separation of different polymers within an aqueous solution when a critical threshold in concentration of polymer is exceeded. We investigate two configurations of water-water emulsions: a sessile drop, and a drop at a planar liquid-liquid interface of an aqueous two-phase solution. A particular class of liquids that spread across solid surfaces are "rinsing" liquids. When applied to a rotating substrate, the dynamics of rinsing liquids are interesting fundamentally in the interaction of several classic modes of spreading and industrially in a variety of cleaning applications, such as in the manufacturing of silicon wafers. An investigation of the spreading of a rinsing liquid across a horizontal, rotating hydrophilic substrate was conducted. We present experimental findings of the spreading radius of the rinsing liquid, in which we observed four distinct growth rates across the parameter space and use lubrication theory to explain the phenomena.

Keywords: Chemical Engineering.
Advisor: Fuller Gerald G.
Shaqfeh Eric S. G. (Eric Stefan Garrido) 
Spakowitz Andrew James
Economic disadvantage as a threat to adaptive adequacy : the role of self-affirmation in improving cognitive and academic performance of the poor

In this dissertation I examine how the experience of economic disadvantage reduces mental bandwidth because it serves as a threat to adaptive adequacy. In chapter 1, I review the contextual factors of poverty in the home, educational, and work settings, and the associated cumulative threats to adaptive adequacy, followed by a summary of the cultural and psychological experiences of economic disadvantage. In chapter 2, I present four studies that correlationally and experimentally test the theory that economic disadvantage serves as a threat to adaptive adequacy and that affirming the self helps buffer low-income but not high-income individuals from the effects of these threats on cognitive functioning. Study 1 shows that lower income individuals in an online sample report having greater sources of threat to adaptive adequacy in their lives, and that these threats help explain why lower income individuals engage in less long-term financial planning. Study 2 experimentally manipulates the experience of self-affirmation in a field study and shows that affirmation moderates the relationship between income and cognitive performance after reflecting on threatening financial scenarios. Study 3 replicates this effect, and shows that affirmation boosts cognitive performance for low-income individuals in the face of threat, but not when participants are exposed to easier financial scenarios. Study 4 is a longitudinal study that examines the effects of affirmation over half a year, and also looks at the correlates of mental bandwidth on important life outcomes. Chapter 3 examines the practical implications of these self-affirmation processes in another cultural context of economic disadvantage with low-income further education college students in the UK. I present findings from over 120 interviews on the psychological barriers to success in this context in Study 5a. I then review correlational results from a survey in Study 5b, where I find that sources of affirmation strongly predict self-reported academic performance above other important psychological constructs. Finally, in Study 6, I present results on a one year registered randomized control trial of a values affirmation intervention on course pass rates and attendance for almost 4,500 students across 13 further education colleges and find that the intervention significantly boosted pass rates by 24% (4.2 percentage points), and especially improved performance for the most economically disadvantaged groups, namely Black Caribbean students and older adults.

Keywords: Psychology.
Advisor: Cohen Geoffrey L. (Geoffrey Lawrence) 
Markus Hazel Rose 
Ross Lee
‘Eden raised in the waste wilderness’: Atonement in Milton’s Paradise Regained

This paper examines a central conundrum for readers of John Milton’s brief epic Paradise Regained: the omission of Christ’s Crucifixion from a poem about the regaining of paradise. Indeed, Milton does not include the word ‘Christ’ anywhere in Paradise Regained’s four books. What then does Milton mean when he writes in the opening lines, “And Eden raised in the waste wilderness”? How is he defining atonement and Jesus’ mission on Earth? The paper’s answer to this question falls in two parts: chapter one argues that the poem presents Jesus’ resistance to Satan’s temptations in the desert as if they were adequate to save mankind through privileging privacy and obedience to the Father above sacrifice and public martyrdom. The second chapter follows upon the conclusions drawn in the first to examine how Jesus’ hermeneutic struggle to interpret the scriptures is sufficient to achieve atonement for fallen man. The thesis ends by reflecting on a theme running throughout the project about the relationship Milton creates between the character of Jesus and the reader of Paradise Regained.

Keywords:  Department of English
Department of English
John Milton
Temptation
Early Modern Period
Paradise Regained
Atonement Theory
Thesis
Advisor: Hoxby Blair
Greene Roland
Education for maximal adaptivity : cognition & learning in expert rap improvisers

In the three papers included in this dissertation, I examine the cognitive processes and learning habits of expert Hip-Hop lyricists (i.e., composers/performers of rap lyrics—rappers) to better understand human adaptability in relation to the processing of organized sound information and its use as a resource in music, language, and linguistically mediated knowledge. I focused my investigations on expert rap improvisers, rappers fluent in the extemporaneous generation of rhyming lyrics and novel rhythmic patterns, set to syncopated rhythms in real time. I chose to study this population because their practice is extremely adaptive in nature, integrating music and language, highly-complex cognitive abilities common to most humans. In the first study, I used electroencephalograph to determine how expert rap improvisers differ from laypersons in their neurological processing of rhyme. In the second study, I use perception-based and feature-based measures of psychoacoustic similarity to determine how expert rap improvisers differ from laypersons in their judgments of half-rhyme acceptability and their classification of speech sounds. In the third paper, I introduce and provide empirical support for a theory of learning, domain traversal, which describes the phenomenon whereby creative writing (and rap in particular) uniquely encourages learners' self-directed engagement with knowledge from multiple domains, and how through this process learners develop (or enhance) dispositions toward metacognitive thinking, interdisciplinary perspective-taking, and lifelong learning. The three papers demonstrate that, apart from its entertainment value, expertise in rap practice is associated with neurological and perceptual adaptation, and the development of adaptive learning dispositions.

Keywords: Education.
Advisor: Ball Arnetha F.
Anttila Arto 
Fujioka Takako
Pea Roy D.
Eevee: Transforming Images to Bridge High-level and Low-level Understanding

Images are central to communication, documentation, and a general understanding of the human world, and because their power so often arises from intangible subjectivities that currently elude computers, it is ever so vital that systems understand the world in the same way we do. People understand and think about images at a high level, but they’re currently constrained to work with images via low level tools and edit operations. We introduce a photo-editing system, Eevee, that can take a high level goal from a user and automatically translate it into a series of low level image edits, a step towards empowering people to interact with images at a higher semantic level. By situating our task within the domain of humorous memetic edits, building upon the notion of visual analogies to drive domain-shifting edits, and utilizing the objective knowledge afforded to us by modern computer vision technology (objects, their segmentations, their relationships, and their attributes), we produce a focused editing method that can link low level image syntax to high level image semantics.

Keywords:  Department of Computer Science
Computer Science
Stanford
Stanford Engineering
Stanford School of Engineering
Human-computer interaction
HCI
Image editing
Photo editing
Graphics
Computer Vision
Thesis
Advisor: Bernstein Michael
Krishna Ranjay
Effect of constraint on mechanical behavior of polymer layers and membranes in energy applications

The role of mechanical constraint is well known in the mechanical behavior of engineering materials such as adhesive joints and alloys. However, in the case of polymer layers and membranes, the effect of mechanical constraint is not always understood. In particular, in energy technologies, device geometry is becoming increasingly complex but the role of mechanical constraint is not explored. In proton exchange membranes (PEM) fuel cells, the PEM is constrained by the adjacent current collector plates such that the membrane can only deform in the flow channel areas. I showed that the tearing energy decreases with increasing constraint associated with a smaller plastic zone and is much lower than the tearing energy with no constraint. In photovoltaics, the backsheet structure is a layered film where the tearing behavior of the individual layers does not necessarily represent the tearing behavior of the entire backsheet. I showed that such characteristic arises from the interaction between the individual layers during the tearing process, where one layer of the backsheet is mechanically constrained by its neighboring layers and the layers may debond from each other. Finally, I present the mechanism through which mechanical constraint enhances the stiffness of a novel polymer composite electrolyte for batteries. The composite electrolyte is composed of a silica aerogel monolith filled with a polymer electrolyte. When the voids of the aerogel are filled with the polymer, the polymer constrained the bending of the cell wall and effectively enhanced the stiffness of the composite. This work highlights the importance of considering the effects of mechanical constraint as it can lead to surprising effects on the mechanical and fracture properties of materials.

Keywords: Mechanical Engineering.
Advisor: Dauskardt R. H. (Reinhold H.) 
Sheppard S. (Sheri) 
Cui Yi
The effect of pressure on iron compounds and the implications for the earth's mantle and core

Understanding the high-pressure behavior of iron and its various alloys is a fundamental step in gaining insight into the deep Earth. Iron is the most common transition metal within the mantle and is the primary element in the core. In order to explore the properties of iron compounds and alloys at high pressures, the conditions of the deep Earth were replicated in diamond anvil cells and the resulting changes were monitored by a various suite of synchrotron techniques. X-ray emission spectroscopy was used to monitor the spin state of the polymorphs of iron hydroxides up to 85 GPa. FeOOH has four polymorphs: goethite (alpha - FeOOH), akaganeite (beta - FeOOH), lepidocrocite (gamma - FeOOH), and a high-pressure phase, epsilon - FeOOH. The structural changes of these polymorphs as a function of pressure were examined using X-ray diffraction to generate equations of state for beta - FeOOH and gamma - FeOOH. Comparing the equation of state results for the beta and gamma phases with recently published data on the alpha and epsilon phases, the beta - FeOOH exhibits distinct behavior from the other three polymorphs, as it is significantly less compressible and does not undergo a spin transition. A systematic examination of these iron hydroxide polymorphs as a function of pressure provides insights into the relation between electronic spin transitions and structural transitions in these OH- and Fe3+ bearing phases that may have implications on understanding of the water content of the mantle. We collected a series of phonon excitation spectra using nuclear resonant inelastic x-ray scattering on 57Fe-enriched on various iron alloys, FeO, Fe3C, FeS and those with varying nickel content (Fe0.9Ni0.1, Fe0.8Ni0.2 and Fe0.7Ni0.3) at pressures up to 40 GPa at room temperature. The phonon density of states were used to extract each composition's force constant and  - factors in order to evaluate their individual effects on stable iron isotope fractionation. This work explores the effect of various light elements, the role of increasing nickel content and the effect of spin transitions on iron isotope fractionation. It provides insights into the potential records left by core formation during planetary differentiation. Radial X-ray diffraction was used in combination with nuclear resonant inelastic x-ray scattering to determine the bulk strength of two iron-nickel alloys (Fe0.88Ni0.12 and Fe0.8Ni0.2) at pressures up to 70 GPa. The results were then used to extrapolate to inner core pressures and temperature in order to evaluate the strength of the inner core. As shear strength is a measure of a material's resistance to flow, these results support dislocation creep as the dominant deformation mechanism in the Earth's inner core.

Keywords: Geological and Environmental Sciences.
Advisor: Mao Wendy (Wendy Li-wen) 
Ewing Rodney C. 
Warren Jessica (Jessica Mendelsohn)
The effect of psychological pain on financial behaviors

This dissertation comprehensively examines a crucial factor that underlies nearly every financial decision that consumers make—psychological pain. The first essay of the dissertation shows that while lacking ownership over a financial decision to spend amplifies the pain associated with losing money, it actually alleviates the pain associated with feeling financially irresponsible. The second essay of the dissertation demonstrates how psychological pain (to avoid losing one's savings) can spill over to another important financial behavior—the decision to invest one's savings. Specifically, this essay shows that when consumers incur more effort to build their savings, they become less willing to invest them. Finally, the third essay argues that the anticipation of future psychological pain can affect consumers' choice of how they pay (with cash or with card) and that they will strategically avoid repeating the painful experience of feeling that one is financially irresponsible by opting to pay with non-trackable payment methods such as cash instead of debit or credit cards.

Keywords: Business.
Advisor: Huang Szu-chi 
Levav Jonathan
Shiv Baba
The effectiveness of white-collar crime enforcement : evidence from the war on terror

This paper studies the deterrent effect of criminal enforcement on white-collar criminal activities. Using the 9/11 terrorist attacks as a shock to the FBI's allocation of investigative resources and priorities, and variations in the Muslim population in the United States as a measure of geographic variations in the shock, I examine two questions: (1) Does the bureau's shift to counter-terrorism investigations after 9/11 lead to a reduction in the enforcement of laws targeting white-collar crime? (2) Does white-collar crime increase as a result of less enforcement? Using a difference-in-differences estimation approach, I find that there is a significantly greater reduction in white-collar criminal cases referred by FBI field offices that shift their investigative focus away from white-collar crime to counter-terrorism. I also find that areas overseen by FBI field offices that shift their attention from white-collar crime to counter-terrorism experience a significantly greater increase in wire fraud, illegal insider trading activities, and fraud within financial institutions.

Keywords: Business.
Advisor: Larcker David F. 
Beyer Anne 
Cohen Lauren 
McNichols Maureen
Piotroski Joseph D. (Joseph David)
Effects of Augmented Reality Projection Obstructions on Social Interactions Between Augmented Reality Headset Wearers and Non-Wearers

Augmented reality smart glasses have made attempts to enter the public sphere as a consumer product. These attempts have not been successful, and one of the reasons stems from negative interactions between people wearing the smart glasses and those not wearing them. One possible root cause of this negative interaction may be from augmented projections obscuring conversation participants visually. This paper seeks to explore why people may have negative interactions in these circumstances. We take measures of social presence, interpersonal attraction, and partner closeness, among others. After studying 96 pairs of participants, we found that when projections obscured a headset wearer’s partner, the headset wearer experiences less social presence than their partner. This has implications on the way we may perceive reality should smart glasses ever become a public consumer product.

Keywords: Augmented reality
mixed reality
social interactions
social presence
Thesis
Advisor: Bailenson Jeremy
Landay James
Effects of bacterial physiology on photoinactivation of pathogens and pathogen indicators

Surface waters worldwide are increasingly impacted by microbial pollution, with subsequent negative impacts on human health, ecosystem health, and economic stability in communities dependent on surface water resources. In order to prevent human exposure to microbial pollution, surface waters intended for recreational use are regularly monitored for culturable fecal indicator bacteria (FIB). However, relationships between FIB and pathogens are not consistently found in recreational waters, and short time-scale variations in FIB concentrations further complicate the use of daily or weekly measurements to accurately characterize water quality. A better understanding of the fate of microbial pollutants in recreational waters is needed to inform predictive water quality modeling efforts. Photoinactivation is one of the most important factors influencing concentrations of microbial pollutants in clear coastal waters. While many studies have been performed to identify the effects of various water quality and exposure variables on photoinactivation, the importance of specific photoinactivation mechanisms and the effects of cellular characteristics on bacterial photoinactivation remain unclear. The goal of this research is to investigate photoinactivation of pathogenic and indicator bacteria in environmental systems, with a specific focus on the influence of cellular physiology. Chapter 2 investigates the relative importance of oxygen-dependent and oxygen-independent mechanisms on the photoinactivation of Staphylococcus aureus, a pathogenic bacterium of emerging concern. The S. aureus cell membrane remained intact during oxic photoinactivation and was damaged during anoxic photoinactivation, suggesting that oxygen-dependent and oxygen-independent photoinactivation mechanisms target different parts of the S. aureus cell. Chapter 3 builds off of conclusions from Chapter 2 by investigating the global transcriptional response of S. aureus under sunlight stress in both oxic and anoxic conditions. Transcriptional responses were different between oxic and anoxic conditions, and increased expression of hemY in the oxic condition also points to the importance of endogenous photosensitizers on bacterial photoinactivation. Chapter 4 presents a spatial survey of enterococci photoinactivation rates from various environmental sources and investigates the role of source and pigmentation on determining sunlight susceptibility. Photoinactivation rate constants were found to vary over nearly an order of magnitude, and pigmentation had a significant impact on the susceptibility of enterococci to sunlight exposure.

Advisor: Boehm Alexandria 
Criddle Craig 
Mitch William A.
Effects of bottom-up and top-down manipulations on visual object processing across the brain

Object recognition is an incredibly important process in day to day life, and is accomplished by the human visual system automatically and effortlessly. However, this process is rarely done in isolation from goal-oriented behavior (or task) performed by the subject. Though much is known about the passive processing of objects in the visual system, far less is understood in both: (1) How tasks affect known responses to objects in visual cortex, and (2) How objects are represented in regions of higher cognition such as prefrontal cortex. Chapter I provides an overview of the existing knowledge regarding object recognition and visual processing of objects, the effects of task engagement on responses in high-level visual cortex, and what is currently known on representations of objects in prefrontal cortex. The study described in chapter II examined how the information content of object classes, or category representations, in different cortical regions changed across three qualitatively different tasks. Here we find that while responses in high-level visual cortex contain robust and task-general representations of visual categories, responses in prefrontal cortex are flexible and task-dependent, supporting their respective functional roles. The study in chapter III further dives into the effects of top-down signals, as well as bottom-up signals, in finer increments and in smaller (and independently derived) of the cortical expanses explored in the first study. The findings from this study reveal a far richer functional heterogeneity in high-level visual cortex than was previously assumed, capturing a diverse set of response profiles to bottom-up and top-down manipulations, as well as their interactions. In prefrontal cortex, no areas are engaged by purely bottom-up manipulation of stimulus, and only a small subset is engaged by the on-task condition, alluding to hypothesized mechanisms of attention. Together, these results expand what is known about the effects of task in high-level visual cortex, as well as the involvement of prefrontal cortex in object processing.

Keywords: Psychology.
Advisor: Grill-Spector Kalanit 
Gardner Justin
Wagner Anthony David