VictorJuiz/thesis huggingface dataset:
Non-equilibrium effects and multiphase flow in porous media [electronic resource]
Keywords: Energy Resources Engineering.

We encounter flow in porous media, knowingly or otherwise, on a daily basis; percolation of precipitation into top soil, ground-water supplies obtained from aquifers (ground-water hydrogeology), ground-water contamination studies and remediation thereof, recovery of oil and gas be it primary, secondary, or tertiary (enhanced-oil-recovery), and storage of Carbon-Dioxide in saline aquifers are just a few examples. Our fundamental understanding of the physics of multiphase flow in porous media is the cornerstone of all endeavors to develop mathematical descriptions and use models to make predictions and decide on the proper course of action in efforts to utilize such resources. The objectives of this research are to investigate the relevant physical mechanisms responsible for instabilities in flow dynamics via detailed experimentation and to incorporate the findings in mathematical models that improve upon the predictive capabilities of current models. This work starts with an experimental program comprising a series of core-scale drainage displacement experiments using pairs of immiscible fluids covering a wide range of viscosity ratios. The experiments are designed and carried out with a focus on the fluid mechanics of drainage processes. The analysis of the experimental observations clearly shows the time-evolution of constitutive relationships and flux functions in the formulation of multiphase flow in porous media. A self-consistent general formulation for multiphase flow in porous media is developed that is firmly based in physics observed in core-scale and micromodel experiments. We account for nonequilibrium effects by considering redistribution time and treat saturation by evolving locally moving time-averages of the saturation. The proposed abstraction provides a non-zero temporal support for constitutive relationships for porous media. Several families of models arise from approximations to the general formulation with various degrees of accuracy. The classical Buckley-Leverett and Barenblatt expressions are examples of these families. We explore the behaviors of a number of special cases arising from the proposed general formulation using established and novel numerical schemes by providing nonlinear physics-based preconditioning to reduce the stiffness inherent in models derived with higher orders of accuracy of approximation. Finally, results of numerical simulations of these models are presented and comparison is made with experimental observations. The agreement observed between numerical and experimental results demonstrates the consistency of the proposed abstraction.
Nonlinear frequency conversion in III-V semiconductor photonic crystals [electronic resource]
Keywords: Electrical Engineering

Nonlinear optical processes provide a physical mechanism for converting the frequency of light. This allows the generation of tunable light sources at wavelengths inaccessible with lasers, leading to a diverse set of applications in fields such as spectroscopy, sensing, and metrology. To make these processes efficient has conventionally required relatively exotic materials that are incompatible with state of the art nanofabrication, resulting in large-area devices that operate at high optical powers and cannot be integrated with on-chip optical and electronic circuits. This dissertation shows how optical nanocavities, by localizing light into sub-cubic optical wavelength volumes with long photon storage times, can greatly enhance the efficiency of nonlinear frequency conversion processes in III-V semiconductors, while simultaneously shrinking the device footprint, reducing the operating power, and providing a scalable on-chip platform. This approach also enables on-chip quantum frequency conversion interfaces, which are crucial for the construction of quantum networks. First, photonic crystal nanocavities in gallium phosphide are shown to generate second harmonic radiation with only nanowatts of coupled optical powers, and efficiency many orders of magnitude greater than in previous nanoscale devices. This approach is then extended to demonstrate sum-frequency generation in GaP photonic crystal cavities with multiple cavity modes, as well as broadband upconversion employing photonic crystal waveguides. The nanocavity-enhanced second harmonic generation is then integrated with a single quantum dot to create a single photon source triggered at 300 MHz by a telecommunication wavelength laser coupled with an external electro-optic modulator, a simpler and faster configuration than standard approaches. The efficiency of all the aforementioned processes can be further improved through resonant photonic crystal nanocavities allowing large frequency separation, which are described in this thesis. Finally, this dissertation presents spectroscopic measurements of quantum systems that emit photons at visible wavelengths, which are promising candidates for a number of quantum and classical applications and well-suited for integration with on-chip frequency conversion.
Non-proportional hazards in clinical trials with failure-time endpoints [electronic resource]
Keywords: Statistics

In clinical trials, enrolled patients are randomized into treatment and control groups to test if the new treatment has advantages over the control. Data have been collected from both groups to form test statistics. For life-threatening diseases, such as cancer and heart attacks, the primary endpoint of a confirmatory trial for a new treatment is time to failure. This endpoint often involves censored data because some subjects may not fail by the end of the study or may have been lost to follow-up. To handle survival data in the problem of explanatory variables, Cox (1972) introduced a semi-parametric model based on the assumption of proportional hazards. In this model, the log ratio of the hazard function of the treatment group to that of the control group is a constant that does not vary over time. Earlier Mantel (1966) introduced the logrank test that is asymptotically efficient for proportional hazards alternative. Both logrank test and proportional hazards regression model have become standard procedures in clinical trials with survival endpoints. Since clinical trials can run for years, interim analyses by a Data and Safety Monitoring Board (DSMB) are typically included in the trial protocol. This led to the development of ``time-sequential'' methods for early stopping during interim analyses. Lan and DeMets (1988) have noted that there are two time scales in time-sequential trials. One is the calendar time t at which interim analysis is carried out, and the other is the information time V(t), which can be measured by the variance of the test statistic (under the null hypothesis) based on all the data collected up to time t and is unknown before time t. Therefore, to determine the sample size and study duration, assumptions have to be made on the accrual rate, the survival distribution of both treatment and control groups, and the censoring distribution. These assumptions are commonly based on the literature concerning related studies and on educated guesses. In particular, since logrank tests and time-invariant hazard ratios are typically used to summarize the results of the studies, it is convenient to assume proportional hazards as the working model at the design stage. During interim analyses, marked discrepancies for the assumptions at the design stage may be observed. Herein we propose a group sequential design that addresses theses discrepancies and thereby makes the trial more efficient in terms of power, study duration and expected sample size. The design allows one to combine the logrank statistic with the more powerful test statistics in case of non-proportional hazards at the terminal stage. A new approach to futility stopping is developed as well as a piecewise constant hazard ratio model replacing the proportional hazards model.
Nonvolatile monolithic three-dimensional field programmable gate array with stacked resistive configuration memory [electronic resource]
Keywords: Electrical Engineering

The majority of conventional Field Programmable Gate Arrays (FPGAs) store their configuration bits in Static Random Access Memory (SRAM) on chip. Configuration SRAM is the primary contributor to the large area, power consumption and delay of FPGAs relative to Application Specific Integrated Circuits (ASICs). The solution is a Three-Dimensional (3D) FPGA, in which the configuration memory is vertically stacked over programmable logic and routing fabric. Several 3D-FPGA concepts with various integration schemes and alternative memory technologies for the configuration memory have been demonstrated recently. However, those concepts required materials and process that may not be compatible or scalable with standard CMOS process. This dissertation presents the first experimental 3D-FPGA with monolithically stacked configuration memory based on the emerging Resistive Random Access Memory (RRAM) technology, which is compatible and scalable with CMOS process. The RRAM, here, are not used in a typical FLASH memory application. Rather, they are used as programmable resistors to construct configuration memory cells that store and represent active static logic. To demonstrate the concept, a 1Kbit nonvolatile resistive configuration memory array and a 17x17-tile 3D-FPGA with 21Kbit configuration are fabricated and tested. This dissertation delves into the architecture, design, implementation, fabrication and validation of the memory array and 3D-FPGA prototypes. Both prototypes are implemented in 0.18um general purpose CMOS process with 1 poly-silicon and 6 metal layers. The programmable resistors (RRAM) are sandwiched between the 5th and 6th metal layers. The measurement results demonstrated the concept of resistive configuration memory and confirmed the programmability and logic functionality of the RRAM based 3D-FPGA. This dissertation also projects the potential improvements in area, energy consumption and delay of the RRAM based 3D-FPGA over conventional SRAM based design, when the prototype is scaled to advanced 65nm CMOS technology. Simulation result shows 40% reduction in area is expected. This work also examines the potential benefits of monolithic 3-layer 3D-FPGA, designed also in the 65nm node. Simulation results show that 70% area reduction is expected.
Not written in stone [electronic resource] : martial and the epigrammatic reader
Keywords: Classics

This dissertation examines the relationship initiated and developed by the Roman epigrammatist Martial with his general reader. Martial creates a position of prominence for the reader in his poetry books; my dissertation, after first examining how Martial presents himself as engaging with the general reader, also explores why it is important for him to do so. I argue that the techniques Martial uses to arrest the reader's attention are deeply bound up with his overall orientation toward the epigram book rather than the individual epigrams within it. By frequently addressing and involving his readers, Martial both educates them on the best way to approach his books as coherent units and rewards their diligent adherence to such an approach. My dissertation goes on to place Martial's engagement with the reader into a broader context by comparing it with the approach of other epigrammatists, especially Posidippus of Pella and Ausonius; these authors are not often brought into critical discussions about Martial, yet their poems (and poetry book, in the case of the New Posidippus) demonstrate as clearly as Martial's own how integral a component of the epigrammatist's approach to writing poetry is the reader's experience of reading it.
The novel and the transience of cultural worlds [electronic resource]
Keywords: Comparative Literature.

The first decades of the 20th century saw the emergence of a robust, holist and historicist notion of culture. This essay examines the moral and aesthetic implications of the paradigm shift spearheaded by this term, as these manifest in the realm of the 20th-century realist novel. At the center of study are three elegiac novels that belong to three literary traditions: The Age of Innocence (1920), Radetzkymarsch (1932) and Past Continuous (1977). Their authors--American Edith Wharton, Austro-Hungarian Joseph Roth and Israeli Yaakov Shabtai--all lived through what they regarded as the demise of the worlds that had shaped them. By articulating this personal experience using a distinctively social-constructivist and post-metaphysical vocabulary, they provided us not only with poignant stories of cultural collapse, but also with subtle meditations on the changing meanings of morality and selfhood in a post-Nietzschean, post-Darwinian intellectual climate. Although Wharton, Roth and Shabtai have each received considerable critical attention in their respective traditions, they have not yet been read together as part of a single, comparative, literary-historical argument. The present study attempts this kind of synthesis. Culture, it seeks to show, emerges from these novels, simultaneously, as an all-pervasive power, which by constructing identities, terminally shapes lives, and as a fragile, parochial and ultimately transitory human creation.
Novel therapeutic targets in soft-tissue sarcomas [electronic resource]
Keywords: Genetics

Cancer is a disease that is characterized by uncontrolled cell proliferation and is the second leading cause of death in the industrialized world. Cancers can be broadly classified based on their cell type of origin: carcinomas arise from cells of the epithelium, leukemias and lymphomas arise from the cells of the hematopoietic system, and sarcomas arise from cells of the mesenchyme. Recent advances in the understanding of the biological mechanisms of cancer initiation, growth, and metastasis have led to a number of new therapeutic modalities with cancer-specific modes of action; these new biotherapeutic drugs have led to significant improvements in the clinical management of many tumor types. However, these advances have predominantly been directed towards the treatments of carcinomas, leukemias, and lymphomas. For sarcomas, there exist very few available targeted therapies, and the treatment of these tumors remains a significant unmet medical need. This dissertation concerns the identification and inhibition of novel therapeutic targets in sarcomas. In Chapter One, a brief introduction to the epidemiology, biology, and available treatments for cancer is presented. In Chapter Two, a relatively understudied receptor tyrosine kinase (RTK), ROR2, is shown to be a prognostic biomarker of patient outcome and to play a pro-tumorigenic role in two soft-tissue sarcomas, leiomyosarcoma (LMS) and gastrointestinal stromal tumor (GIST). In Chapter Three, a cell surface protein, CD47, is shown to prevent immune-mediated clearance of LMS tumors by macrophages, and anti-CD47 monoclonal antibody (mAb) drugs are demonstrated to have therapeutic efficacy against LMS tumors in vitro and in vivo. In Chapter Four, a mAb directed towards KIT, an RTK over-expressed and mutated in GIST, is shown to slow tumor growth in vitro and in vivo in GIST tumors that are both sensitive and resistant to treatment with the current standard of care drug, imatinib. In Chapter Five, a computational approach is taken to identify novel drugs for LMS by comparing gene expression profiles of these tumors to those of benign lesions arising from the same cell type; drugs identified by this analysis were then tested in vitro on LMS cells. Chapters Six and Seven contain discussions and concluding remarks on the results presented in earlier chapters. In sum, these results help further the identification and experimental validation of novel therapeutic targets in soft-tissue sarcomas. It is hoped that these studies will add to the scientific understanding of soft-tissue sarcoma biology and will help to enable further scientific and clinical advances to improve the lives of patients suffering from these cancers.
Numerical investigation of turbulence and mixing in shock-accelerated compressible multi-component flows [electronic resource]
Keywords: Aeronautics and Astronautics

The problem of Richtmyer-Meshkov instability is numerically studied in canonical configuration. The discontinuities in the flow field (such as shock waves, contact surfaces and material interfaces) are captured by using a shock-capturing method coupled with a high-order high-resolution compact differencing scheme. Verification and validation is conducted by simulating 1-D and 2-D canonical test problems and comparing the numerical results with experimental data and previous numerical results. High resolution numerical simulation of the impulsive acceleration of a dense gas curtain in air by a Mach 1.21 planar shock (modeling the experiments by Balakumar et al. PoF 2008) is carried out by solving the 3-D compressible multi-species Navier-Stokes equation coupled with a localized artificial diffusivity method to capture discontinuities in the flow-field. The simulations account for the presence of three species in the flow-field: air, SF6 and acetone (used as a tracer species in the experiments). The reshock process is studied by re-impacting the evolving curtain with a reflected shock wave. Turbulence statistics computed in the flow-field following reshock are reported and compared with experiment where possible. Inertial range scaling, vorticity anisotropy and Reynolds stress development are studied in the reshocked flow. The high resolution data set is used to test certain modeling assumptions appearing in mixing models (BHR model) that have been traditionally used to study variable density flows. Finally preliminary results are shown from a 3-dimensional calculation of a planar shock interacting with a planar perturbed interface between air and SF6.
Observing protein machines in action [electronic resource] : foundations for a chemical approach
Keywords: Chemistry

The conformational gymnastics and specific interactions of individual proteins drive the majority of intracellular processes. Yet detailed, dynamic information for these interactions and conformational changes is difficult to obtain and in most cases remains unavailable or inaccessible. In this work, we develop and validate methodology to rapidly obtain global coverage of residue specific information about a protein's conformation, under a set of conditions or after initiation of an event. Cysteine mutations are used as probes of solvent accessibility and changes in modification rate serve as a corollary for changing conformation. To allow rapid generation of this cysteine modification platform, we first increased the robustness and scope of our cysteine misincorporation technology to the entire E. coli genetic code. This allowed for controlled, low frequency cysteine insertion at every position. Second, to demonstrate the power of cysteine modification to determine lightly populated, equilibrium conformations, we used thiol exchange to identify the high energy unfolding intermediates of RNase H D10A. Finally, to elucidate conformational changes that occur on the millisecond time scale, we developed technology and validated chemistry to take 2 millisecond snapshots of a protein's solvent accessibility through rapid pulse/quench cysteine modification.
On stars orbiting massive black holes [electronic resource]
Keywords: Physics

This thesis shows that a star orbiting a massive hole can interact with the hole and the hole's attendant disc in many ways, and produce quasi-periodic electro-magnetic (EM) signals. It is possible to use these signals to learn about the space-time around the hole, to probe the parameters of the hole, and even to test General Relativity (GR) in the strong-field regime. One model is about the collisions of a star bound to a massive hole and the accretion disc of the hole. When the star crosses the innermost region of the disc, the stellar orbit precesses, and signals produced by star-disc collisions are quasi-periodic. The temporal behavior of these signals provides information about the mass and spin of the hole. Another model discussed is the Roche mass-transfer of a star. A star approaches a massive hole slowly in a circular, equatorial orbit. When the star fills its Roche lobe, mass will start to transfer through the first Lagrange point, on a time scale between the thermal time and the dynamical time. The stellar orbit expands following the onset of mass-transfer in most cases, in order to keep on filling the Roche lobe. The stream forms a torus around the hole, and a hot spot is formed where the stream hits the torus. This orbiting hot spot will give a quasi-periodic modulation to the hole's quiescent radiation, for an inclined observer. From the period and intensity the modulation flux, we can constrain the hole's parameters. There will be coupled EM and gravitational wave signals produced during this Roche process, giving a good test of GR.
Open wounds [electronic resource] : literature, memory, and space in four rural Iberian communities
Keywords: Iberian and Latin American Cultures

In this dissertation, I analyze the impact of four contemporary novels that deal with memory of the Spanish Civil War and postwar period in the rural Iberian communities that they describe. The novels are: Les veus del Pamano by Jaume Cabré (Catalonia), Soinujolearen semea (2003) (The Accordionist's Son [2007]) by Bernardo Atxaga (The Basque Country), O lapis do carpinteiro (1998) by Manuel Rivas (Galicia), and Cielos de barro (2000) by Dulce Chacón (Extremadura). I am specifically interested in the role that space plays in the creation and reception of literature on the one hand, and how readership of these novels within specific regions of the Spanish state impacts processes of recuperation, conservation, and transmission of historical memory on the other. My analysis is based on field research that I conducted in the areas of Pallars Sobirà, (Catalonia), Asteasu (The Basque Country), Cesantes/Redondela (Galicia), and Zafra (Extremadura) in which I interviewed readers of these novels in order to ask them about their reactions to the novels.