VictorJuiz/thesis huggingface dataset:
Filtered floer and symplectic homology via Gromov-Witten theory [electronic resource]

We describe a procedure for computing Floer and symplectic homology groups, with action filtration and algebraic operations, in a class of examples. Namely, we consider closed monotone symplectic manifolds with smooth symplectic divisors, Poincaré dual to a positive multiple of the symplectic form. We express the Floer homology of the manifold and the symplectic homology of the complement of the divisor, for a special class of Hamiltonians, in terms of absolute and relative Gromov--Witten invariants, and some additional Morse-theoretic information. As an application, we compute the symplectic homology rings of cotangent bundles of spheres, and compare our results with an earlier computation in string topology.

Keywords: Mathematics
Advisor: Eliashberg Y.
Galatius Søren
Ionel Eleny advisor. Thesis advisor
Filtering and control of flow in a model scramjet engine [electronic resource]

The continuous fueling of a scramjet causes a shock to develop in the isolator which will cause the engine to stall when it reaches the inlet. To prevent the engine from stalling fuel may be injected in bursts which allows the shock to weaken between each burst. The rate at which the shock grows and dissipates depends strongly on the amount of fuel injected, the geometry of the engine and the environment in which the engine is operated. In realistic operating conditions, the environment is never fully known to the operator and the amount of heat released by combustion may be more or less than intended. As a result when a deterministically stable fueling schedule is applied in the presence of stochastic perturbations to the heat release mechanism or random fluctuations in the environment the engine may stall. This thesis presents a control algorithm that prevents a model scramjet from stalling when operated for an extended period of time in an uncertain environment. A quasi one dimensional model of a scramjet engine is used to study the effect of heat release on the development and growth of a shock in the isolator. It is shown that when the engine is fueled with periodic bursts and operated under deterministic conditions there is a clear threshold between fueling parameters ranges where the flow in the engine remains stable and where the engine stalls. A novel parametrization of the uncertainty in the heat-release mechanism and inflow properties is presented; it is demonstrated that the instabilities identified in the deterministic study are amplified by the addition of stochastic perturbations and cause significant variability in the state of the engine. This uncertainty in the state of the engine motivates the use of a filtering algorithm to accurately estimate the full state of flow in the engine based on noisy observations; both the particle filter and the ensemble Kalman filter are shown to accurately track the location of the shock in the engine. Using the filtered estimate of the engine's state, a heuristic control for heat-release is developed that prevents the engine from stalling and delivers three times the thrust as the stable periodic heat-release schedule.

Advisor: Glynn Peter W. primary advisor. Thesis advisor
Papanicolaou George primary advisor. Thesis advisor
Iaccarino Gianluca advisor. Thesis advisor
The final lilt of songs [electronic resource] : late Whitman and the long American century

Critics have long dismissed Walt Whitman's late poetry as a frail echo of his ambitious antebellum poems; subsequent authors often view him as a poet whose utopian political vision no longer offers a tenable model for their respective realities. In both of these cases, Whitman remains a poet in many ways lost to us. Contesting these narratives of decline and desuetude, my dissertation rescues the poet's late work from neglect and demonstrates how Whitman, precisely in the estranging forms his late work takes, offers a charged poetic response to the post-Civil War years and plays a critically overlooked role in conceptions of subsequent poetries.

Advisor: Gelpi Albert primary advisor. Thesis advisor
Greene Roland
Jenkins Nicholas (Nicholas Richard)
Kaufman Robert advisor. Thesis advisor
A finite element approach to the simulation of hydraulic fractures with lag [electronic resource]

In this thesis, a finite-element-based algorithm is presented to simulate plane-strain hydraulic fractures in an impermeable elastic medium where the crack path is not known a priori. The algorithm accounts for the nonlinear coupling between the fluid pressure and the crack opening and separately tracks the evolution of the crack tip and the fluid front. It therefore allows the existence of a fluid lag. The fluid front is advanced explicitly in time, but the crack tip is determined implicitly by enforcing Griffith's criterion and maximum energy release rate. A spatial discretization is created that conforms to the crack path by perturbing the nodes of a background mesh. The coupling between the fluid and the rock is enforced by simultaneously solving for the fluid pressure and the crack opening at each time step. Verification of the algorithm is provided for straight hydraulic fractures by performing sample simulations and comparing them to two known similarity solutions. Also, sample simulations are carried out for the general case of curvilinear fractures for which the crack path is not known a priori.

Keywords: Mechanical Engineering
Advisor: Lew Adrian primary advisor. Thesis advisor
Kuhl Ellen
Pinsky Peter M. (Peter Michael)
Finite representation of an infinite molecular system [electronic resource] : algorithms and applications

The utility of molecular simulation techniques relies on the ability to accurately and efficiently explore the appropriate distribution of configurations. For this reason, many simulation techniques use approximations that reduce the dimensionality of a system. The result is a molecular representation with fewer degrees of freedom than would otherwise be included. This dissertation explores a number of methods aimed at reducing the dimensionality for various molecular systems. The main focus of this work is the development of a new hybrid explicit/implicit solvent model capable of accurately reproducing solvation effects with significantly fewer explicitly represented molecules.

Keywords: Chemistry
Advisor: Pande Vijay primary advisor. Thesis advisor
Andersen Hans
Boxer Steven G. (Steven George)
Flow separation control for robust conical diffuser design [electronic resource]

In many practical applications of conical diffusers, the flow is fed by an annular flow passage formed by a center body. The annular inlet causes two possible regions of flow separation in the diffuser. The first is the separated wake of the center body and the second occurs if the boundary layer on the diffuser outer wall separates due to the adverse pressure gradient. The diffuser flow is further complicated by the strong coupling between the core flow and the outer wall boundary layer. The goal of this work was to optimize diffuser performance by controlling both separation regions. Magnetic resonance velocimetry was used to acquire three-dimensional three-component mean velocity measurements for an extensive array of diffuser configurations. The results show that a large separation bubble existed in the wake of the center body in the absence of flow control. Passive geometric perturbations were found to be ineffective in controlling the central separation bubble. An axisymmetric Coanda jet was shown to eliminate the bubble at a relatively low jet flow rate. The boundary layer separated asymmetrically when the Coanda jet was too strong. This mandates simultaneous control of both separation regions. A wavy-edge step-wall diffuser design was used to stabilize the outer wall boundary layer separation by fixing its location and allowing the separation bubbles to close quickly. The combination of Coanda blowing and the wavy-edge step-wall diffuser produced an outflow that was free of any flow separation. This configuration improved flow uniformity, increased pressure recovery, reduced loss, and reduced flow unsteadiness.

Keywords: Mechanical Engineering
Advisor: Eaton John K. primary advisor. Thesis advisor
Elkins Christopher J. advisor. Thesis advisor
Iaccarino Gianluca advisor. Thesis advisor
Follow the money [electronic resource] : representations of capital in Galdós

Taking into account John Vernon's assertion in Money and Fiction that "money is perhaps the most common theme in nineteenth-century fiction" (7), it is not surprising that money is a recurrent theme in the novelas contemporáneas of nineteenth-century Spanish novelist, Benito Peréz Galdós. While literary economic criticism is blooming in literary studies, nineteenth-century Hispanists have not approached their work using this critical reading. This study attempts to answer the following question: What is Galdós revealing about his contemporary society through his representations of capital? This analysis literally follows the money in order to examine Galdós's scathing criticism of the Spanish middle class as an unproductive and adynamic social force. While there are many studies that link the disavowal of the Spanish bourgeoisie—high and low—in fulfilling the political role that its European counterparts had played in transforming the political and economic structures of the ancien régime, none have looked at the economic criticism Galdós makes in the "Contemporary Novels, " from La desheredada (1881) to Miau (1888), which I call the novels of capital. In order to have an adequate sense of Galdós's depiction of money, his views about money, his financial practices, his profits from his artistic labor, and his positioning within the marketplace becomes increasingly pertinent. Chapter one, "Galdós as an English Businessman in the Fabrication of a Novel Market, " explores our novelist's own relation to capital and the forces of the market. The careful examination of Galdós's artistic milieu and financial practices contextualizes the role of the market in his novelistic discourse. The following two chapters look at the representations of money through metaphors for capital and exchange—work and conspicuous consumption. Chapter two, "Señoritismo: The Anti-Work Ethic in Galdós, " examines both work and the lack of work in Galdós's "Contemporary Novels." Chapter three, "Conspicuous Consumption: The Transformation of Economic Capital into Symbolic Capital, " looks at the recurrent theme of conspicuous consumption of both male and female characters as a means of converting economic capital into symbolic capital in order maintain or attain a reputable position in society. Through the representations of capital Galdós reveals that values are shifting—moral and exchange values—and what once had been stable economic and societal tenets are no longer stable.

Keywords: Iberian and Latin American Cultures
Advisor: Predmore Michael P. primary advisor. Thesis advisor
Ruffinelli Jorge advisor. Thesis advisor
Surwillo Lisa advisor. Thesis advisor
Force field parameterization techniques using genetic algorithm evolutionary strategies [electronic resource]

A novel evolutionary strategy in the form of a steady-state genetic algorithm (GA) is presented for the derivation of an accurate parameterization of the shell model potential as applied to a metal oxide perovskite. Using barium titanate, (BaTiO$_3$ or BTO), as a testbed material, the GA technique is implemented by fitting to a density functional theory (DFT) rendered landscape of the four phases of the material, representing a wide range of unit cell configurations. Using the stochastic processes of recombination and mutation which are fundamental to the GA approach, a parameter set of the shell model potential has been identified that not only matches the energetics of the reference database accurately, but is also able to directly capture the implicit elasto-mechanical characterization of the material that is embedded in the DFT analysis. The evolutionary strategy is described in detail, and it is noted that in its current form it is directly applicable to a diverse number of other metal oxides for which similar analysis is entirely compatible. The method is then compared to the conjugate gradient technique whereby it is seen that while the gradient-based method faces significant challenges in identifying globally optimal parameterizations despite repeated initiations at distinct starting points for the search, the GA method is able to continuously explore the rugged parametric solution space to identify those regions which produce the greatest fidelity to the DFT energies. The validation of the technique includes renditions of equilibrium lattice lengths, unit cell volume and bulk modulus for the four phases of BTO using static energetic calculations. In addition, using molecular dynamics (MD) in both the canonical and isobaric-isothermal ensembles, the elastic stiffness constants, coefficient of thermal expansion, bulk modulus, and average electronic polarization for the cubic phase have been derived. These results are in excellent agreement with empirical analysis presented in the literature.

Keywords: Mechanical Engineering
Advisor: Darve Eric primary advisor. Thesis advisor
Cai Wei
Srivastava Deepak
Forest dynamics across temporal and spatial scales [electronic resource]

The research conducted in this dissertation is focused on understanding different aspects of forest degradation and regeneration in the tropics. Similar to the multiple spatial and temporal scales this topic encompasses, the studies described in this dissertation encompass spatial scales ranging from as large as the Brazilian Amazon to as small as an individual leaf and temporal scales ranging from one-minute micro-climate measurements to multi-decadal remote sensing analyses. The causes and effects of forest degradation are numerous and require methods and concepts crossing traditional disciplinary boundaries. Likewise, this dissertation incorporates varied methods and concepts as required to understand forest dynamics within different study systems. The core of this dissertation is the development and integration of new remote sensing methods. In this theme, I use a variety of remote sensors, including satellite based Landsat and Quickbird sensors and the Carnegie Airborne Observatory (CAO) -- which integrates airborne LiDAR with hyperspectral imagery. I also include a study (chapter 5) focusing specifically on issues related to forest dynamics following swidden agricultural abandonment.

Keywords: Biology
Advisor: Asner Gregory P. primary advisor. Thesis advisor
Field Christopher B.
Dirzo Rodolfo advisor. Thesis advisor
Vitousek Peter Morrison advisor. Thesis advisor
Framed [electronic resource] : bilingual education and the construction of national identities

Abstract This work examines what role, if any, bilingual education has in the construction of a national identity. I explore the issue in the Autonomous Basque Community in Spain. This region provides the discussion with a well known nationalist struggle and a wide variety of academic models and experiences of bilingual education. In this environment I ask, when and how do issues of nationalism and identity enter into language education? How does policy design differ from classroom implementation and results? What is the role of parents, teacher, students or the community at large? These questions are explored using ethnographic data gathering methods, interviews, surveys, and analysis of language use across various levels of engagement with bilingual education. The analysis moves from general public opinion, to school culture and classroom ethnographies. Along the way, this research addresses politicized or toxic schools, silent resistance, and teachers whose lesson plan is co-opted and rendered as something different. The experiences of students in schools show that language education is not just one grade, one teacher and is far from being a perfectly oiled nationalist machinery. Students emerge as expert frame casters, actively analyzing the sociolinguistic environment of every classroom and tailoring their participation accordingly. Early competence in abstracting content and framing interpersonal exchanges are key to understanding how it is that, in certain schools, youth may be radicalized in spite of teachers' efforts while in other schools silenced majorities find their way through cultures in conflict to give birth to new cultural identities and political agendas.

Keywords: Anthropology
Advisor: Fox James primary advisor. Thesis advisor
Barnett Clifford R.
McDermott Ray (Raymond Patrick)
Zulaika Joseba advisor. Thesis advisor
A framework for firm-level ecosystem service valuation and representation [electronic resource]

The private sector -- irrespective of industry -- has begun to increasingly embrace the (environmental) sustainability "megatrend". Corporate leaders agree that sustainable development should be explored at the strategic level; however firms continue to struggle with rationally operationalizing sustainability. Part of the challenge of determining the shape and extent to which concepts of sustainability are incorporated into operational decisions is the form and interpretation of environmental information. This includes two key components: i) information which links operational decisions to environmental impact, including how impact may affect the firm; and, ii) what value is placed on prospects that incorporate such information. In this dissertation, I develop a firm-level ecosystem service valuation framework, designed to address these environmental information and representation gaps. Adopting a "systems" approach from industrial ecology, I link firm operational decisions to their impact on owned ecosystems by representing changes in natural capital within the strict requirements of international accounting norms. I develop the valuation framework through four distinct aspects. In the first, I identify and explain how the developed framework addresses the needs of firms to include ecosystem services within operational decision. This enables the groundwork for more detailed investigations in the other three aspects. In the second aspect, I use ecological models in two cases to demonstrate the ability of the framework to provide fundamental knowledge of a given ecosystem service and its operational limit state(s). The first case -- total suspended solids removal from stormwater runoff via soil -- demonstrates the level of ecosystem service characterization required to enable a market-based valuation. The second case -- phosphorus removal from wastewater effluent via estuary -- provides a much richer example by explicitly demonstrating the inclusion of limit states as part of a comprehensive understanding of the performance of an ecosystem service under various operational loadings. I next turn to the third aspect, which provides a method for the application of a market-based value, using the welfare economics concept of functional substitutability. I conclude with a presentation of my fourth aspect, where I compare the unit value of phosphorus removal yielded by traditional accounting and that of thermoeconomics, in order to explore a more rational determination of engineered service value used within functional substitutability for ecosystem service valuation.

Advisor: Lepech Michael primary advisor. Thesis advisor
Schwegler Benedict R.
Weyant John P. (John Peter) advisor. Thesis advisor
Frequency conversion of single photons [electronic resource] : physics, devices, and applications

The ability to manipulate the carrier frequency of quantum states of light, through a process called quantum frequency conversion (QFC), has numerous applications for both technology and basic science. For example, one can upconvert a single-photon-level signal in the 1.5-micron telecommunications band (where single-photon detection has been challenging) to a visible wavelength to take advantage of well-developed single-photon detectors based on silicon avalanche photodiodes. On the more fundamental side, the manipulation of a single photon's frequency may enable the construction of networks of dissimilar quantum systems, whereby one can imagine generating many-body entangled quantum states over vast distances. Quantum frequency conversion will only be useful if it can be done both efficiently and with little added noise. We demonstrated a conversion efficiency exceeding 99.99% using reverse-proton-exchange waveguides in periodically poled lithium niobate with approximately 150 mW of pump power. Noise has been a more serious issue: the generation of noise photons, due to inelastic scattering of light from the strong pump laser used to drive the frequency conversion, has limited the utility of QFC devices in many applications. We present an analysis of the two primary noise processes in QFC devices (spontaneous Raman scattering and spontaneous parametric fluorescence), and offer solutions on how they may be either mitigated or avoided completely. We then discuss applications of QFC devices for up- and downconversion of single-photon signals. We used a long-wavelength pump to enable high-efficiency and low-noise single-photon detection for 1550-nm telecom band signals, and demonstrated a cascaded frequency conversion approach that enabled low timing jitter as well. We also demonstrated a downconversion quantum interface, in which the emission from a single semiconductor quantum dot at a wavelength of 910 nm was downconverted to 1560 nm while maintaining the single-photon character of the light. The results presented in this dissertation indicate a promising future for QFC devices as the field of quantum communications matures.

Keywords: Applied Physics
Advisor: Fejer Martin M. (Martin Michael) primary advisor. Thesis advisor
Byer R. L. (Robert L.)
Yamamoto Yoshihisa advisor. Thesis advisor