Physical Sciences and Mathematics Commons^™

Neutron Study Of Structured Polymers At Interfaces, Thusitha Etampawala

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This work focuses on interfacial structure and dynamics of structured polymers in thin films and in solutions using neutron techniques accompanied by atomic force microscopy. We probed polymers with a common theme that were highly segregated either because of presence of ionic groups or topological constraints. In these polymers the interfacial regions often define their function in different applications such as clean energy, printing adhesions and drug delivery systems. Thin film studies include systems of polystyrene/sulfonated polystyrene, a rigid sulfonated polyphenylene and polystyrene three-arm stars/linear polystyrene. The first two systems include ionic components and the last exhibits topological constraints. Polystyrene …

Surface Shape Perception In Volumetric Stereo Displays, Meng Zhu

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In complex volume visualization applications, understanding the displayed objects and their spatial relationships is challenging for several reasons. One of the most important obstacles is that these objects can be translucent and can overlap spatially, making it difficult to understand their spatial structures. However, in many applications, for example medical visualization, it is crucial to have an accurate understanding of the spatial relationships among objects. The addition of visual cues has the potential to help human perception in these visualization tasks. Descriptive line elements, in particular, have been found to be effective in conveying shape information in surface-based graphics as …

Arachidonic Acid Reverses The Pyriproxyfen And Ibuprofen Induced Toxicity In Daphnia Magna, Gautam Kumar Ginjupalli

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Healthy reproduction and neonatal sex ratios of Daphnia are crucial to the health of the aquatic ecosystems in which Daphnia play principal roles in trophic transfer of nutrients. Combinations of environmental factors such as availability and quality of diet, overcrowding, hypoxia, reduced photoperiods and fall in ambient temperatures perturb normal parthenogeneic reproduction and induce sexual reproduction through male production. Male production provides a mechanism for overcoming specific stressors such as overcrowding and overwinter pond desiccation. However, it also induces a decrease in the Daphnia population that could have adverse implications on the pond ecosystem that depend on Daphnia . Interestingly, …

Ecology And Impacts Of Coyotes (Canis Latrans) In The Southeastern United States, Cady Etheredge

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Recent coyote (Canis latrans ) colonization of the southeastern United States has prompted speculation on the top-down effects of a new top predator on systems which have gone without a strong predator presence since the extirpation of the red wolf (Canis rufus ). This dissertation reports on the results of a series of investigations of the potential impact of coyotes on raccoons (Procyon lotor ) and other management issues related to coyotes in the Southeast. Chapters 1-3 present indirect field tests of the Mesopredator Release Hypothesis. Chapter 4 presents an overview of the current knowledge of the …

Chemical Evolution Of The Neutron-Rich Iron-Group Isotopes And Implications For The Formation Of Fun Cais, Tianhong Yu

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Calcium-aluminum-rich inclusions (CAIs) are millimeter-sized refractory objects found in primitive meteorites. CAIs are considered as some of the first solids to form in the solar system, because they are refractory. FUN CAIs, those with Fractionated and Unknown Nuclear effects, are a small subset of CAIs. These FUN CAIs show correlated excesses and deficits in the neutron-rich iron-group isotopes such as ⁴⁸ Ca and ⁵⁰ Ti which regular CAIs do not. Interestingly, these isotopes are most likely produced infrequently but in huge quantities in a rare class of thermonuclear (Type Ia) supernovae. I propose that the isotopic effects in the neutron-rich …

Exploratory Synthesis Of New Iron(Ii,Iii)-Containing Polyanion Framework Solids Of Electrochemical And Magnetic Interest, Liurukara Sanjeewa

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The studies demonstrated in this dissertation were primarily focused on the synthesis, structure and property characterizations of iron(II,III) containing framework solids. The scope of this research is threefold: 1) explore new iron(II, III)-containing open framework structures in hopes of creating new materials, useful in the areas of both Li- and Na-ion battery applications; 2) synthesis and characterization of low-dimensional magnetic nanostructures exhibiting novel magnetic properties due to confined magnetic lattices; and 3) conduct structure/property correlation studies to identify the origins of any unusual physical phenomena associated with these new compounds.

In the syntheses of new compounds, molten salt fluxes were …

Approximation In Multiobjective Optimization With Applications, Lakmali Weerasena

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Over the last couple of decades, the field of multiobjective optimization has received much attention in solving real-life optimization problems in science, engineering, economics and other fields where optimal decisions need to be made in the presence of trade-offs between two or more conflicting objective functions. The conflicting nature of objective functions implies a solution set for a multiobjective optimization problem. Obtaining this set is difficult for many reasons, and a variety of approaches for approximating it either partially or entirely have been proposed.

In response to the growing interest in approximation, this research investigates developing a theory and methodology …

Room Generation, Removal, And Recovery In Udk 3.5, Scott Johnson

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This paper explores algorithms and techniques for creating an extended game world that represents a radical departure from the widely used static content in current use with most games featuring procedurally generated game worlds. Using the Unreal Development Kit 3.5 game engine and focusing on a small set of rooms and doors the research sets to create a game world that is in constant flux and addresses issues of game development limitations on the size of game worlds.

Aqueous Geochemistry Of Rhenium And Chromium In Saltstone: Implications For Understanding Technetium Mobility In Saltstone, Amanda Hatfield

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Incorporation of low level radioactive waste in cementitious materials is an important waste disposal technology in practice at a U.S. DOE facility, the Savannah River Site (SRS), Aiken, SC. One of the major risk drivers, technetium (99Tc)

Virtualizing Intelligent River®: A Comparative Study Of Alternative Virtualization Technologies, Aravindh Sampathkumar

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Emerging cloud computing infrastructure models facilitate a modern and efficient way of utilizing computing resources, enabling applications to scale with varying demands over time. The core enabler of the cloud computing paradigm is virtualization. The concept is not new; virtualization has garnered significant research attention, fostering a race to achieve the lowest possible virtualization overhead. The evolution has led to three primary virtualization approaches: full-virtualization, para-virtualization, and container-based virtualization, each with a unique set of strengths and weaknesses. Thus it becomes important to study and evaluate their quantitative and qualitative differences. The operational requirements of the Intelligent River® middleware system …

The Fabrication And Study Of Silver Nanoparticle Structures, Aubrie Pfirman

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Nanotechnology and the synthesis of nanoparticle systems are attractive in part because of interesting, tunable optical and electrical properties that are not observed with bulk material. Silver nanoparticles (Ag NPs) interact with visible light more efficiently than any other system due to the excitation of plasmon resonances, which are the collective oscillations of the free electron density. These collective oscillations produce an enhanced local electromagnetic (EM) field: this field is responsible for highly-utilized phenomena such as surface enhanced Raman scattering (SERS), enhanced fluorescence, surface enhanced infrared absorption (SEIRA), and many others. Many experiments have been conducted to optimize and tailor …

Molecular Dynamics Simulations Using Advanced Sampling And Polarizable Force Fields, Tugba Kucukkal

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Molecular dynamics (MD) simulations were carried out for aqueous dipeptides, water over self-assembled monolayer (SAM) surfaces, and the nicotinic acetylcholine receptor (nAChR) ion channel. The main goal is to use advanced methods to increase the accuracy of molecular dynamics simulations while seeking solutions to problems relevant to chemistry, biophysics and materials science. In addition, activation energies of several cyclodimerization reactions were studied quantum mechanically. The simulations of the aqueous dipeptides and SAM surfaces involve modeling and detailed analysis of interfacial water, which is of interest to a range of fields from biology to materials science. For example, water has a …

Factors Affecting The Surface-Mediated Reduction Of Plutonium In The Presence Of Pure Mineral Phases, Amy Hixon

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The overall objective of the research is to investigate the mechanistic and kinetic aspects of the surface-mediated reduction of plutonium. The first chapter is a critical review of plutonium sorption to pure mineral phases. The objective is to study if and how the mechanisms by which plutonium interacts with mineral surfaces are connected to mechanisms for the surface-mediated reduction of plutonium. The main conclusion of the review is that advanced spectroscopy, microscopy, and molecular modeling are needed to fully understand not only the surface structure of pure mineral phases, but also the coordination and bonding environment of plutonium surface complexes. …

Genetic Algorithm Techniques In Climate Changepoint Problems, Shanghong Li

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The first part of this dissertation studies genetic algorithms as a means of estimating the number of changepoints and their locations in a climatic time series. Such methods bypass classical subsegmentation algorithms, which sometimes yield suboptimal conclusions. Minimum description length techniques are introduced. These techniques require optimizing an objective function over all possible changepoint numbers and location times. Our general objective functions allow for correlated data, reference station aspects, and/or non-normal marginal distributions, all common features of climate time series. As an exhaustive evaluation of all changepoint configurations is not possible, the optimization is accomplished via a genetic algorithm that …

An Investigation Into The Interactions Of Gold Nanoparticles With Aquatic Vascular Macrophytes, James Glenn

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Nanomaterials (NMs) have promised lighter, stronger, smaller and more efficient products in areas such as electronics, medicines and even environmental sectors. This investigation started at the base of the food chain and characterized NMs interactions with aquatic plants. Citrate capped gold nanoparticles were used as a model nanoparticle to track fate and gain insight on factors that influence gold nanoparticle (AuNP) bioavailability and absorption. Four species of aquatic macrophytes were investigated. Azolla caroliniana, Myriophyllum simulans, Egeria densa and Myriophyllum aquaticum were selected due to growth habitat, leaf morphology and root structure. Because aquatic plants absorb the majority of their nutrients …

L1 Methods For Shrinkage And Correlation, Jie Shen

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This dissertation explored the idea of L1 norm in solving two statistical problems including multiple linear regression and diagnostic checking in time series. In recent years L1 shrinkage methods have become popular in linear regression as they can achieve simultaneous variable selection and parameter estimation. Their objective functions containing a least squares term and an L1 penalty term which can produce sparse solutions (Fan and Li, 2001). Least absolute shrinkage and selection operator (Lasso) was the first L1 penalized method proposed and has been widely used in practice. But the Lasso estimator has noticeable bias and is inconsistent for variable …

Characterization Of The Hydrogeology And Stress State In The Vicinity Of The Homestake Mine, Lead, Sd, Johnathan Ebenhack

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Underground workings in fractured rock are common worldwide. They have applications in numerous areas and fields of study. These include mining operations, civil engineering projects like tunnels and underground facilities, and research projects that require underground laboratories such as the physics research being conducted by Sanford Laboratory at the former Homestake mine and Fermi Laboratory near Chicago (Bahcall et al. 2001, Elsworth 2009, Sadoulet et al. 2006, bge science@DUSEL, fnal.gov). These excavations can reach several kilometers in depth including the 3.9 km deep TauTona mine in South Africa, the 3 km deep LaRonde mine in Quebec and the 2.4 km …

Lithostratigraphic And Petrophysical Analysis Of The Middle Devonian Marcellus Shale At The Mamont Prospect, Westmoreland County, Pennsylvania, Ty Taylor

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The organic-rich Middle Devonian Marcellus Shale of the Appalachian basin is a rapidly developing natural gas play. Stratigraphic boundaries of the Marcellus Shale in Westmoreland County, Pennsylvania were identified using geophysical logs from 10 vertical gas-producing wells in a 23 sq. km area. Gamma-ray, bulk density, and resistivity well logs were examined to assess hydrocarbon potential. Values of porosity, total organic carbon (TOC), and water saturation (SW) were derived and mapped by incorporating well-log data into Marcellus-specific formulas. Gamma-ray, penetration (minutes per foot drilled), and mud-logging gas (total gas) from 12 horizontal wells from within the study area were also …

Sequential Autotrophic-Heterotrophic Culture Of Scenedesmus Spp. For Lipid Production, Jazmine Taylor

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Algae are fascinating organisms that are receiving growing attention for their versatility on many fronts of research areas. Immense amounts of research is being conducted to find solutions to challenges in energy and climate change. A large portion of research is focused on algae as a potential solution to both of these issues. The focus of this research is to look at algae closer to home as a local, economical resource to aid in solving both of these problems. The algal genus Scenedesmus was tested for growth in a bi-phased scheme: photoautotrophically for carbon sequestration then heterotrophically on glycerol for …

Macroscopic Investigation Of Ionic- And Nano-Silver Toxicity To Soil Nitrification Process, Abdurrahman Masrahi

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The worldwide production of engineered nanoparticles (ENPs) has grown rapidly in our era because of the popular applications in industrial and consumer markets. Especially silver (Ag) NP is one of mostly common ENPs in our consumer products due to its unique antimicrobial property. However, release of AgNPs into environment through wastewater treatment plants poses a question that what impact AgNPs have on microbially mediated processes in environment (e.g., nutrient and trace element cycles). In the last decades, numerous toxicological studies of AgNPs on bacteria have been conducted in pure culture systems, and several different antimicrobial mechanisms of AgNPs have been …

Stimulated Raman Scattering In Micro Sphere Resonators, Ruoyu Zhang

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Micro sphere resonators that hold optical whisper gallery modes (WGMs) provide an innovative option for implementing micro optical resonators. The unique properties of the micro sphere resonator make it capable to introduce resonance for various optical phenomenon, like stimulated Raman scattering (SRS), in micron scale.

This thesis illustrates the characteristics of micro sphere resonators and demonstrates the resonance-enhanced SRS in micro sphere resonators with reduce threshold power. Both theoretical and experimental results are presented. Coupling model for WGM is derived in transfer matrix method. Simulation analyses for mode pattern of WGMs are solved based on mathematic model and finite element …

The Detection Of A Light Echo From Sn 2007af, Dina Drozdov

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Type Ia supernovae are widely studied for their uniform properties, which make them ideal candidates for cosmological surveys. Although these exploding stars are popular targets, key funda-mental questions about their nature remain, and new techniques need to be developed to investigate the progenitor system and explosion mechanisms. Light echoes are created by light scattering off dust that reaches the observer after the direct path light from the explosion arrived and have been studied for the past 100 years. Light echoes from Type Ia supernovae are rare, with only a few cases being discovered in the past decades. Because light echoes …

On The Cuspidality Of Maass-Gritsenko And Mixed Level Lifts, Dania Zantout

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Gesture-Based Robot Path Shaping, Paul Yanik

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For many individuals, aging is frequently associated with diminished mobility and dexterity. Such decreases may be accompanied by a loss of independence, increased burden to caregivers, or institutionalization. It is foreseen that the ability to retain independence and quality of life as one ages will increasingly depend on environmental sensing and robotics which facilitate aging in place. The development of ubiquitous sensing strategies in the home underpins the promise of adaptive services, assistive robotics, and architectural design which would support a person's ability to live independently as they age. Instrumentation (sensors and processing) which is capable of recognizing the actions …

Extreme Value Theory In Periodic Time Series, Zhiyun Gong

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Extreme data points are important in environmental, financial, and insurance settings. In this work, we consider two topics on extremes from environmental data. Many environmental time series have a seasonal structure. The first part presents an approach to identify the rare events of such series based on time series residuals. Here, periodic autoregressive moving-average models are applied to describe the series. The methods justify the application of classical peaks over threshold methods to estimated versions of the one-step-ahead prediction errors of the series. Such methods enable the seasonal means, variances, and autocorrelations of the series to be taken into account. …

Bond-Centric Modifications To Bond-Order Potentials And Ab-Initio Evaluation Of Nanostructured Materials Properties, Jaewoong Hur

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An improvement to the AIREBO potential for hydrocarbons is presented in which contribu-tions to the bond order are determined by the local bonding environment around the bond, rather than the average of the environments around the two constituent atoms. This bond-centric approach decreases the errors by ∼80% in the fullerene-type systems for which the original approach leads to the most severe errors. With the newly developed and parameterized method, energy errors are less than 0.7eV for a collection of hydrocarbon molecules not used in the fitting. This modified AIREBO potential is expected to be more useful not only for the …

Advancements In Finite Element Methods For Newtonian And Non-Newtonian Flows, Keith Galvin

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This dissertation studies two important problems in the mathematics of computational fluid dynamics. The first problem concerns the accurate and efficient simulation of incompressible, viscous Newtonian flows, described by the Navier-Stokes equations. A direct numerical simulation of these types of flows is, in most cases, not computationally feasible. Hence, the first half of this work studies two separate types of models designed to more accurately and efficient simulate these flows. The second half focuses on the defective boundary problem for non-Newtonian flows. Non-Newtonian flows are generally governed by more complex modeling equations, and the lack of standard Dirichlet or Neumann …

Mathematical Optimization For Engineering Design Problems, Brian Dandurand

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Applications in engineering design and the material sciences motivate the development of optimization theory in a manner that additionally draws from other branches of mathematics including the functional, complex, and numerical analyses.
The first contribution, motivated by an automotive design application, extends multiobjective optimization theory under the assumption that the problem information is not available in its entirety to a single decision maker as traditionally assumed in the multiobjective optimization literature. Rather, the problem information and the design control are distributed among different decision makers. This requirement appears in the design of an automotive system whose subsystem components themselves correspond …

Iron Abundances And Atmospheric Parameters Of Red Giants In The Open Cluster Ic 4756, Julie Djordjevic

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Three red giants were investigated within the open cluster IC 4756 using observations taken from the McDonald Observatory's 2.1m Otto Struve Telescope and the Sandiford Cassegrain Echelle Spectrometer (SES). Iron abundances were calculated for each star based on the equivalent widths of Fe I and Fe II lines measured using the line lists of Bubar and King (2010) and Schuler et al. (2005). Also derived were the basic atmospheric parameters: effective temperature, surface gravity, metallicity, and microturbulence. Her 35, Her 85, and Her 249 were found to have corresponding [Fe I/H] of 0.06 ± 0.04, -0.16 ± 0.03, and -0.16 …

Microbial Exo-Enzyme Activities In Soil As Infuenced By Polyphenol Chemistries, Daniella Freese

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Soil organic matter decomposition is directly driven by the soil extracellular enzymes excreted by soil microorganisms. Therefore, factors which impede extracellular enzyme activity would result in retarding the rate of soil organic matter decomposition. Several factors in the soil may influence soil extracellular enzymes including the plant secondary metabolites, polyphenols- tannins and lignins. However, thus far few investigations have considered the direct and indirect impacts of polyphenols on soil enzyme activities. Hence, three investigations were conducted to understand the ecological impacts of tannins and lignins on soil extracellular enzyme activities.
Tannins, further classified as condensed and hydrolysable tannins, can hamper …