VictorJuiz/thesis huggingface dataset:
Manipulating light absorption in ultrathin semiconductor layers for optoelectronic applications [electronic resource]

The achievement of strong light absorption in ultrathin layers of material has been of great scientific and practical interest for many years. The realization of ultra-thin strongly-absorbing layers can increase performance, reduce fabrication and materials cost of many thin-film optoelectronic device applications, including next generation solar cells, solar fuel generation and ultrathin photodetectors. In this thesis, we have demonstrated how to attain strong light absorption in the ultrathin layer of active materials in both theory and experiment. We have achieved this goal by harnessing two fundamentally different skills of light trapping based on the ray optics or wave optics. The first approach of ray optics utilizes geometric light traps that configure the substrate into the form of V groove and increase optical path length. We briefly mentioned this skill in chapter 2 by applying it to the organic solar cells to improve device efficiency. The second approach of wave optics relies on the resonance effect of nanostructure to concentrate light in the nano-scaled volume of material. We assembled these resonant building blocks into the form of array configuration to realize ultrathin strongly absorbing layer. The second approach is explained in most part of this thesis with detailed sub-skills. Specifically, we exhibited two different designing strategies for wave optics light trapping, the wavelength scaled design (in chapter 3) and the subwavelength scaled design (in chapter 4 & 5). We analyzed the two designing strategies in terms of their conceptual and physical differences and applied each to particular applications. The first designing strategy is applied to the solar fuel generation by nanostructuring photocatalysts materials to facilitate hydrogen generation rate. And the second strategy is demonstrated by designing germanium metafilm absorber for general optoelectronic applications. In addition to the specific examples demonstrated above, these light absorption methods can be used in the more general ultrathin optoelectronic applications such as diverse solar energy harvesting devices, photodetectors, and even light emitting devices by efficiently extracting light.

Keywords: Electrical Engineering.
Advisor: Brongersma Mark L. primary advisor. Thesis advisor
Fan Shanhui
Miller Dave A. advisor. Thesis advisor
The marriage of Walt Whitman and Emily Dickinson [electronic resource] : an inquiry into spousal poetics

Though Emily Dickinson and Walt Whitman spent their lives unwed, their afterlives have never been free of marital vows. Take Whitman, who—having ducked an early proposal from Anne Gilchrist, a widowed, English admirer—finds himself the imaginary suitor to Ronald Johnson and Hart Crane. Dickinson, however, on account of her perceived seclusion, prompts us not to thoughts of consummation, but of extended courtship. In the following study I investigate how marriage and weddings permeate the core poetry in question, before exploring the marital permutations in the afterlives of Walt and Emily. Marriage serves as both subject matter and metaphor, leading me to such texts as Edward Weston's photographs for a 1941 Leaves of Grass (made with Charis Wilson, his new, and soon to be ex-, wife); the poetry of same-sex weddings; Jerome Charyn's daring novel The Secret Life of Emily Dickinson (2010); Joyce Carol Oates's short story "EDickinsonRepliLuxe" (2008); and Paul Di Filippo's peculiar steampunk novella, "Walt and Emily" (1995), where the titular characters fall in love.

Keywords: English.
Advisor: Greene Roland
Fields Kenneth
Jones Gavin Roger
Masks, Origins, and Copies in Chang-Rae Lee’s Native Speaker

Published at a time when the Los Angeles Riots remained fresh in America’s mind, Chang-Rae Lee’s novel, Native Speaker, skyrocketed to critical acclaim. Kim’s paper explores how Native Speaker navigates the implications of belonging and control over a narrative. This research focuses on how the narration of a traumatic moment can become an entry point for understanding the narrator’s agency, and what such readings might illuminate in transnational literatures.

Keywords:  Department of English
Lee
trauma
trauma theory
Asian American
poststructuralism
Thesis
Advisor: Palumbo-Liu David
Moser Joyce
Massive-scale processing of record-oriented and graph data [electronic resource]

Many data-driven applications perform computations on large volumes of data that do not fit on a single computer. These applications typically must use parallel shared-nothing distributed software systems to perform their computations. This thesis addresses challenges in large-scale distributed data processing with a particular focus on two primary areas: (i) theoretical foundations for understanding the costs of distribution; and (ii) processing large-scale graph data. The first part of this thesis presents a theoretical framework for the MapReduce system, to analyze the cost of distribution for different problems domains, and for evaluating the ``goodness'' of different algorithms. We identify a fundamental tradeoff between the parallelism and communication costs of algorithms. We first study the setting when computations are constrained to a single round of MapReduce. In this setting, we capture the cost of distributing a problem by deriving a lower-bound curve on the communication cost of any algorithm that solves the problem for different parallelism levels. We derive lower-bound curves for several problems, and prove that existing or new one-round algorithms solving these problems are optimal, i.e., incur the minimum possible communication cost for different parallelism levels. We then show that by allowing multiple rounds of MapReduce computations, we can solve problems more efficiently than any possible one-round algorithm. The second part of this thesis addresses challenges in systems for processing large-scale graph data, with the goal of making graph computation more efficient and easier to program and debug. We focus on systems that are modeled after Google's Pregel framework for large-scale distributed graph processing. We begin by describing an open-source version of Pregel we developed, called GPS (for Graph Processing System). We then describe new static and dynamic schemes for partitioning graphs across machines, and we present experimental results on the performance effects of different partitioning schemes. Next, we describe a set of algorithmic optimizations that address commonly-appearing inefficiencies in algorithms programmed on Pregel-like systems. Because it can be very difficult to debug programs in Pregel-like systems, we developed a new replay-style debugger called Graft. In addition, we defined and implemented a set of high-level parallelizable graph primitives, called HelP (for High-level Primitives), as an alternative to programming graph algorithms using the low-level vertex-centric functions of existing systems. HelP primitives capture several commonly appearing operations in large-scale graph computations. We motivate and describe Graft and HelP using real-world applications and algorithms.

Advisor: Ré Christopher primary advisor. Thesis advisor
Widom Jennifer primary advisor. Thesis advisor
Ullman Jeffrey D.
A matched pair, cluster randomized, controlled trial of a novel film intervention designed to motivate earthquake-resistant construction in the Kathmandu Valley, Nepal [electronic resource]

A 20-minute documentary film was created to accelerate the rate at which Nepalese communities retrofit or rebuild their local public school buildings to be life-safe in the event of a major earthquake. It features local Nepalese as role models who have already strengthened their schools, and is based on the theory of communicating actionable risk, diffusion of innovation theory, and social cognitive theory. Public schools in Kathmandu Valley with buildings in need of seismic work were assessed for eligibility in the study. Of these, 16 were selected and matched into 8 pairs based on seismic condition of the buildings. One school in each pair was randomly assigned to see the intervention film and the other to see an attention placebo control film on an unrelated topic. Pre and post observations were recorded from 761 adult participants, using a questionnaire created for this purpose. Comparisons between the two groups of schools were made with the school as the unit of analysis. When compared to the control schools, the schools whose community members saw the retrofit intervention film statistically significantly increased their: 1) knowledge of specific actions to take in support of earthquake-resistant construction, 2) belief in the feasibility of making buildings earthquake-resistant, 3) willingness to support seismic strengthening of the local school building, and 4) likelihood to recommend to others that they build earthquake-resistant homes. This outcome suggests that employing a film featuring community members who have already taken the desired action increases factors that may accelerate adoption of risk reduction actions by others who are similar to them.

Keywords: Geological and Environmental Sciences.
Advisor: Hilley George E. primary advisor. Thesis advisor
Robinson Thomas (Thomas N.) advisor. Thesis advisor
Wood Michele advisor. Thesis advisor
Mean field games with common noise [electronic resource]

Mean Field Games (MFG) are a limit of stochastic differential games with a large number of identical players. They were proposed and first studied by Lasry and Lions and independently by Caines, Huang, and Malhame in 2006. They have attracted a lot of interest in the past decades due to their application in many fields. By assuming independence among each agent, taking the limit as N goes to infinity reduces a problem to a fully-coupled system of forward-backward partial differential equations (PDE). The backward one is a Hamilton-Jacobi-Bellman (HJB) equation for the value function of each player while the forward one is the Fokker-Planck (FP) equation for the evolution of the players distribution. This limiting system is more tractable and one can use its solution to approximate the Nash equilibrium strategy of N-player games. In this thesis, we consider the MFG model in the presence of common noise, relaxing the usual independence assumption of individual random noise. The presence of common noise clearly adds an extra layer of complexity to the problem as the distribution of players now evolves stochastically. Our first task is proving existence and uniqueness of a Nash equilibrium strategy for this game, showing wellposedness of MFG with common noise. We use a probabilistic approach, namely the Stochastic Maximum Principle (SMP), instead of a PDE approach. This approach gives us a forward-backward stochastic differential equation (FBSDE) of McKean-Vlasov type instead of coupled HJB-FP equations. This was first done by Carmona and Delarue in the case of no common noise and we extend their results to MFG with common noise. We are able to extend their results under a linear-convexity framework and a weak monotonicity assumption on the cost functions. In addition to wellposedness results, we also prove the Markov property of McKean-Vlasov FBSDE by proving the existence of a decoupling function. In the second part of this thesis, we consider MFG models when the common noise is small. For simplicity, we assume a quadratic running cost function while keeping a general terminal cost function satisfying the same assumptions as in the first part. Our goal is to give an approximation of Nash equilibrium of this game using the solution from the original MFG with no common noise, which could be described through a finite-dimensional system of PDEs. We characterize the first order approximation terms as the solution to a linear FBSDE of mean-field type. We then show that the solution to this FBSDE is a centered Gaussian process with respect to the common noise. By assuming regularity of the decoupling function of the 0-MFG problem, we can find an explicit solution showing that they are in the form of a stochastic integral with respect to the common noise with the integrands adapted to the information from the 0-MFG only. We then are able to compute the covariance function explicitly.

Keywords: Mathematics.
Advisor: Papanicolaou George primary advisor. Thesis advisor
Menz Georg
Ryzhik Leonid advisor. Thesis advisor
Measurement and interpretation of travel-time shifts in the context of time-distance helioseismic detection of meridional flow [electronic resource]

The role of meridional flow in maintaining the solar dynamo and differential rotation in the solar convection zone is not well understood and is currently under scrutiny. Traditional flux-transport dynamo models have posited the well known single-cell meridional flow with poleward flow at the photosphere and equatorward flow near the base of the convection zone. However, recent investigations seem to be revealing a discrepant picture of meridional flow which is at least double celled in the radial direction. In this work standard time-distance helioseismic techniques are modified and used to probe the solar convection zone to accurately determine the structure of meridional circulation. Helioseismology is a powerful tool for measuring the structure and flows on the solar surface and within the solar interior. It uses the photospherically visible aspect of (acoustic, surface-gravity) waves, that propagate and interfere throughout the Sun to form standing oscillation modes, as probes to make inferences about the structure and flows on the solar surface and interior. Time-distance helioseismology is based on measuring the travel-times of wave-packets moving between distinct points on the solar surface. Specifically, travel-time shifts obtained by calculating the difference in the travel-times of counter-propagating waves between pairs of points on the solar surface yield information about flows throughout the Sun. In this work time-distance helioseismic techniques are applied on artificial as well as solar velocity images to detect travel-time shift signals due to meridional flow, and modifications are suggested to enhance the signal-to-noise ratio of travel-time shift measurements. The artificial datacubes are constructed by embedding various meridional flow models in 3D acoustic wave propagation simulators, which are then used to discuss the interpretation of travel-time shifts, so that in the future an inversion procedure may be designed to accurately calculate meridional flow velocities. The solar data is obtained from the Helioseismic and Magnetic Imager (HMI) instrument aboard the Solar Dynamics Observatory (SDO) spacecraft and is used to measure travel-time shifts due to meridional flow in the solar convection zone non-standard helioseismic techniques. The issue of a systematic error dubbed as the "center-to-limb" effect that contaminates the travel-time shift measurements of solar meridional flow is also addressed in this work.

Keywords: Electrical Engineering.
Advisor: Scherrer Philip H.
Duvall Thomas Lee
Zebker Howard A. advisor. Thesis advisor
Measuring and modeling DDT, chlordane, and mercury in activated carbon amended sediments and water [electronic resource]

Activated carbon (AC) as an in-situ amendment for the remediation of contaminated sediments has attracted considerable attention from researchers, regulators, and industry. However, knowledge gaps related to field measurements of AC performance and long-term modeling of AC-amended sediments currently impede the widespread adoption of the technology. The intent of this study is to improve in-situ measurements of AC-amended sediments and to test the prevailing conceptual and mathematical models describing AC performance in the field. Polyethylene (PE) passive samplers can be used to estimate water concentration of hydrophobic organic contaminants. A Fickian approach to modeling hydrophobic organic compound uptake by PE developed in this study significantly improved the accuracy of these water measurements in non-equilibrium conditions, particularly in well-agitated systems in which PE-phase mass transfer resistance is significant. Polyethylene partitioning and diffusion coefficients were measured for the organochlorine pesticides DDT, DDT metabolites, chlordane, and dieldrin. An 18-month field mesocosm study was conducted at an intertidal marsh creek impacted with organochlorine pesticides to evaluate AC amendment under several application conditions. Organochlorine pesticide availability, as measured by PE concentration, was reduced throughout the trial period, with chlordane and DDT PE concentration reductions of 85-91% and 83-85%, respectively, 18 months post-treatment in the mesocosms amended with granular activated carbon (GAC). A substantial particle size effect was observed. For example, chlordane concentration in PE was reduced by 91% 6-months post deployment in the powdered AC mesocosm (PAC), compared with 68% in the GAC mesocosm. An existing mass transfer model was parameterized and applied to the mesocosms for model validation purposes. Overall, the mass transfer model reproduced the field observations well for the major constituents of pore water concentration and the model captured the relative impact of the application conditions. In preliminary field studies, AC amendment reduced mercury and methylmercury sediment pore water concentration by 70 and 81%, respectively. Activated carbon dosed at 5% reduced mercury pore water concentration by > 85% in confirmatory laboratory tests.

Keywords: Civil and Environmental Engineering.
Advisor: Luthy Richard G. primary advisor. Thesis advisor
Mitch William A. advisor. Thesis advisor
Werner David
Measuring and recreating hydrodynamic environments at biologically relevant scales [electronic resource]

Marine communities are fundamentally shaped by water motion, which provides many essential functions for a wide variety of marine organisms, such as gamete fertilization, transportation, and food and nutrient delivery. However, it often remains challenging to directly measure how individual organisms are affected by their immediate flow environments. Water motion in marine habitats is often dynamic and unpredictable, so average velocity measurements are unlikely to adequately capture the environment at biologically relevant scales. Furthermore, many organisms (e.g., plankton) are small (≤1mm), which limits potentially available techniques. Finally, the physical harshness of some environments, such as wave-swept shores, further constrains the number of viable tools. To address these challenges, I have developed several novel techniques to both measure and recreate environmental water motion at very fine temporal and spatial scales. First, I designed and manufactured a field-deployable flow sensor capable of measuring water velocities in the rocky intertidal zone at scales relevant to settling spores and larvae. I found that high water velocities (> 2m/s) can occur often (more than once per minute) even at heights just 0.250mm above the substrate. A larva attached to the substrate may find shelter from these peak velocities by hiding behind local topography or by settling in the right tidal conditions. Second, I built a wave chamber capable of replicating the extreme flows found in the intertidal zone and recorded adult barnacles feeding in these flows. I observed that barnacles are able to feed in high water velocities (> 1m/s), and that their feeding rates may potentially be independent of wave velocity. Finally, I measured flow patterns on the Great Barrier Reef at scales relevant to settling coral larvae, and then exposed coral larvae to a replication of these flow patterns in a lab setting. I found that because coral larvae are weak swimmers compared to their ambient flow environment, they are unable to affect their trajectories in even benign flows. Thus, these coral larvae require turbulence to deposit them onto the substrate. The studies in this thesis explore several ways in which marine organisms directly interact with their hydrodynamic environments, and how their performances during these interactions can potentially shape the distributions we observe in the field.

Keywords: Biology.
Advisor: Denny Mark W.
Goldbogen Jeremy advisor. Thesis advisor
Somero George N. advisor. Thesis advisor
Watanabe James Minoru
Measuring force in the developing zebrafish embryo using an expressible tension sensor [electronic resource]

Early vertebrate development is a mechanically dynamic process. Embryos undergo radical morphologic changes to mold a ball of cells into the recognizable planes of a frog or fish or mouse. In the last 40 years, the zebrafish has emerged as a powerful system for studying these early movements in a vertebrate system. Its large, optically transparent embryos make it a good candidate for advanced microscopy techniques, and in recent years this model organism has been the setting for a host of cutting edge microscopy methodologies. One technique that has been comparatively overlooked in the fish is the use of Fluorescence Lifetime Imaging (FLIM), specifically in conjunction with Forster Resonance Energy Transfer (FRET). FRET is a powerful technique for studying real time, in vivo protein dynamics on the nanometer scale. FLIM allows us to apply this technique in the noisy embryo background without the need for cumbersome spectral bleed-through corrections. In this work, we adapt previously published controls for use in the zebrafish system and then take a systematic approach to developing the best analytical practices for FLIM-FRET in the zebrafish embryo. After developing FLIM-FRET in the early embryo background, we adapt a recently published expressible, FRET-based stress sensor capable of measuring piconewton levels of force in vivo (Grashoff et. al. 2010). We insert this Tension Sensor Module (TSMod) into the zebrafish Epithelial Cell Adhesion Molecule (EpCAM) and use it to make direct measurements of the tensions experienced during early development. In doing so we show that the EpCAM molecule holds between 0.5 and 1.5 piconewtons of force during zebrafish epiboly and that the leading margin is under greater tension than other regions of the developing embryo. This work represents the first use of FLIM-FRET in the zebrafish embryo and the first direct measure of molecular tension in a developing vertebrate.

Keywords: Molecular and Cellular Physiology.
Advisor: Riedel-Kruse Hans
Dunn Alexander Robert advisor. Thesis advisor
Goodman Miriam Beth advisor. Thesis advisor
Talbot William