Physical Sciences and Mathematics Commons^™

Transport Of Terrigenous Sediment And Horseshoe Crab Eggs In The Swash Zone Of An Estuarine Foreshore In Delaware Bay, New Jersey, Usa, Sherestha Saini

Dissertations

Identification of processes responsible for egg exhumation and transport in the swash zone is paramount to conservation of species that use the intertidal foreshore. One example where the understanding of these processes is critical to egg exhumation, transport and deposition is in Delaware Bay, USA. Beaches in Delaware Bay provide foraging grounds to many shorebird species that migrate thousands of miles from Central and South America to feed on nutrient rich horseshoe crab eggs during their peak spawning season. Eggs laid at depth by horseshoe crabs are exhumed and transported by bioturbation, wave and swash processes and made available to …

Example Based Texture Synthesis And Quantification Of Texture Quality, Chandralekha De

Dissertations

Textures have been used effectively to create realistic environments for virtual worlds by reproducing the surface appearances. One of the widely-used methods for creating textures is the example based texture synthesis method. In this method of generating a texture of arbitrary size, an input image from the real world is provided. This input image is used for the basis of generating large textures. Various methods based on the underlying pattern of the image have been used to create these textures; however, the problem of finding an algorithm which provides a good output is still an open research issue. Moreover, the …

Dispersibility Of And Adsorption On Functionalized Carbon Nanotubes, Susana Addo Ntim

Dissertations

As the applications of carbon nanotubes (CNTs) proliferate, mass production and widespread use of these nanocarbons will continue to rise. While raw, unrefined, and hydrophobic carbon nanotubes tend to settle out of aqueous media/environments, water dispersible, functionalized CNTs (F-CNTs) will contaminate water resources and will also be highly bioavailable on exposure. Therefore, there is a need to develop an understanding of the fate of F-CNTs in aqueous media.

The colloidal behavior of aqueous dispersions of F-CNTs formed via carboxylation and polymer wrapping with polyvinyl pyrrolidone (PVP) is investigated. The presence of polymer on the nanotube surface provides steric stabilization, and …

Mathematical Models Of Combustion At High Pressure, Daniel Fong

Dissertations

In this dissertation, we develop new mathematical theories of flame propagation that are valid at elevated, or extreme, pressures. Of particular interest is the regime of burning in which the pressure exceeds the critical pressure of the species undergoing chemical reaction. Fluids and flames are known to behave differently under these extreme conditions as opposed to atmospheric pressure. The focus of this dissertation is to investigate these differences by deriving reduced models that contain the unique features.

In the first part of this dissertation, we analyze the structure of laminar diffusion flames at high pressure in the limit of large …

Molecular Network Development Of A Thermosetting Epoxy-Amine Polymer, Christopher Michael Sahagun

Dissertations

i ABSTRACT MOLECULAR NETWORK DEVELOPMENT OF A THERMOSETTING EPOXY-AMINE POLYMER by Christopher Michael Sahagun May 2012 Epoxy-amine resins find wide application as the matrix material of high performance polymer composites due to their favorable mechanical properties, thermal properties and solvent stability. These properties are derived from the complicated, highly crosslinked molecular network that is characteristic of these thermoset polymers. The connectivity of the molecular network has a strong influence on the physical performance of the finished part. Non-homogeneity in the network structure can degrade these favorable properties through the introduction of low-energy pathways for solvent penetration or fracture propagation. This …

Function Estimation Of Irregularly Spaced Data With Long Memory Dependence, Rosalie Michelle Wheeler

Dissertations

We examine the problem of estimating an underlying function from collected data. The methods considered include parametric regression, density estimation, kernel estimation, wavelet regression, and specific results from when our underlying function f\left(x\right) is a member of the Besov or the Triebel spaces. Then we consider the problem of long memory error in several settings, including data which is equally spaced, data which is unequally spaced, and data which is a member of the Holder class and several other spaces. Ultimately we focus on three different problems. The first involves using linear interpolation or local averaging to account for the …

Modern Approaches For Multifunctional Hydrolyzying Thiol-Ene Networks, Nicole Marie Mackey

Dissertations

Marine fouling has been an expensive and time-consuming process for navies and fishermen by the accumulation of marine algae and animals on artificial surfaces. Many coatings have been proposed to combat marine fouling in efforts to extend the lifetime of objects immersed in sea water. However, all coatings tested have either failed to resist fouling for a significant length of time or have released toxins into the environment. We have investigated an environmentally friendly approach to address the problem of marine fouling through the synthesis and preparation of a biocidal and a self-polishing coating. Both novel monomers were prepared containing …

Error Estimation Techniques To Refine Overlapping Aerial Image Mosaic Processes Via Detected Parameters, William Glenn Bond

Dissertations

In this paper, I propose to demonstrate a means of error estimation preprocessing in the assembly of overlapping aerial image mosaics. The mosaic program automatically assembles several hundred aerial images from a data set by aligning them, via image registration using a pattern search method, onto a GIS grid.

The method presented first locates the images from a data set that it predicts will not align well via the mosaic process, then it uses a correlation function, optimized by a modified Hooke and Jeeves algorithm, to provide a more optimal transformation function input to the mosaic program. Using this improved …

A Bisphenol-A-Based Resin System That Cures Via Triazole Ring Formation For Marine Composite Applications, Irene Elizabeth Gorman

Dissertations

Large composite panels, such as those utilized in marine applications, cannot be economically cured in an autoclave. For these structures the elevated temperatures necessary to achieve high crosslink density must come from the curing reaction itself. We are developing a resin system that cures via triazole ring formation (cycloaddition reaction of azides with terminal alkynes) instead of the traditional oxirane/amine reaction. The high exothermicity of the azido/alkyne reaction is expected to yield higher extents of reaction under ambient-cure conditions, making the resin system potentially suitable for "out-of-autoclave" curing processes. This work was conducted through a multi-tiered approach involving synthesis, kinetic …

New Dual Initiators For Polyisobutylene-Based Block And Star Polymers, Yaling Zhu

Dissertations

Polyisobutylene (PIB), available solely by living carbocationic polymerization (LCP), is a commercially important polymer with excellent thermal stability, good flexibility and extraordinary impermeability to gases. Due to these attractive properties, coupling PIB to other polymer blocks is expected to result in new and useful products. Two types of new dual initiators possessing initiating sites for both LCP and atom transfer radical polymerization (ATRP), have been designed for the preparation of AB linear and A2B miktoarm star copolymers, where A is PIB-based block copolymer that grows cationically and B is polyacrylate or other radically-derived polymer block, without intermediate modification.

Mono-cationic mono-radical …

Surface, Bulk, And Rheological Properties Of Polyhedral Oligomeric Silsesquioxane/High Density Polyethylene Nanocomposites, Robert Douglas Cook Jr.

Dissertations

In the formulation of high performance nanocomposites, control of miscibility and dispersion of filler material through a polymer matrix is of utmost importance. Due to their inorganic nature most nanofillers are insoluble in polymers, leading to costly/complicated surface modification as a primary means of increasing miscibility and interaction with organic matrices. Polyhedral oligomeric silsesquioxane (POSS) nanostructured chemicals offer an attractive alternative to conventional nanofillers. Due to their hybrid organic-inorganic nature, POSS has the potential to be tailored for miscibility in a wide range of organic matrices not by chemical surface modification but through modification of the molecular structure of the …

Optical And Electrochemical Sensors For The Detection Of Metal Ions And Nerve Gas Mimics Via Fluorescein And Coumarin Derivatives, Fasil Adefris Abebe

Dissertations

Trace element detection of metals, for example, iron, Copper and zinc, are important in biological systems and in the environment. Many of us are aware that our cells contain metal ions that are “tied” up in proteins. However, chelatable or “free” trace elements can also be found in small quantities, and can have a negative impact on our bodies. Despite the increasing surge in developing sensors for metals and nerve gas agents, efficient detection still remains a challenge. Among the various sensors developed so far, fluorescence sensors play an important role due to their simplicity. I design fluorescein-based chemosensors for …

Efficient Reinforcement Learning In Multiple-Agent Systems And Its Application In Cognitive Radio Networks, Jing Zhang

Dissertations

The objective of reinforcement learning in multiple-agent systems is to find an efficient learning method for the agents to behave optimally. Finding Nash equilibrium has become the common learning target for the optimality. However, finding Nash equilibrium is a PPAD (Polynomial Parity Arguments on Directed graphs)-complete problem. The conventional methods can find Nash equilibrium for some special types of Markov games.

This dissertation proposes a new reinforcement learning algorithm to improve the search efficiency and effectiveness for multiple-agent systems. This algorithm is based on the definition of Nash equilibrium and utilizes the greedy and rational features of the agents. When …

Adaptive Radial Basis Function Neural Networks-Based Real Time Harmonics Estimation And Pwm Control For Active Power Filters, Eyad Kh Almaita

Dissertations

With the proliferation of nonlinear loads in the power system, harmonic pollution becomes a serious problem that affects the power quality in both transmission and distribution systems. Active power filters (APF) have been proven to be one of the most successful methods for mitigating harmonics problems. So far, different techniques have been used in harmonics extraction and control of APF to satisfy the fast response and the accuracy required by the APF. Neural networks techniques have been used successfully in different real-time and complex situations. This dissertation demonstrates four main tasks; (i) a novel adaptive radial basis function neural networks …

Optical And Electrochemical Properties Of Monolayer Protected Gold Clusters Modified With Fluorophores, Mary Sajini Devadas

Dissertations

My research focused on the synthesis, characterization and the investigation of the optical and electrochemical properties of monolayer-protected quantum-sized gold clusters. Significant research attention was focused on the solution phase optical and electrochemical properties of these clusters. Highly monodisperse Au clusters with different types of ligands were successfully synthesized with sizes varying from 1 nm to 13 nm. These preformed gold clusters were modified with fluorophores and pseudo-rotaxanes for developing better nonlinear optical materials for sensing and biological imaging purposes. We have tried to focus on the interaction of the outer ligand shell, made up of –S-Au-S-Au-S- bonds, with the …

Using An Ontology To Improve The Web Search Experience, Tian Tian

Dissertations

The search terms that a user passes to a search engine are often ambiguous, referring to homonyms. The results in these cases are a mixture of links to documents that contain different meanings of the search terms. Current search engines provide suggested query completions in a dropdown list. However, such lists are not well organized, mixing completions for different meanings. In addition, the suggested search phrases are not discriminating enough. Moreover, current search engines often return an unexpected number of results. Zero hits are naturally undesirable, while too many hits are likely to be overwhelming and of low precision.

This …

Terahertz Wireless Communication, Ke Su

Dissertations

The goal of this thesis is to explore Terahertz (THz) wireless communication technology. More specifically the objective is to develop and characterize several THz communication systems and study the effect of atmosphere propagation through fog droplets and dust particles on THz communications.

For demonstration, a THz continuous wave (CW) photomixing system is designed. Terahertz signals are phase encoded with both analog ramp signals and pseudorandom binary data, transmitted over a short distance, and detected. The limitation of transmission bandwidth, low single to noise ratio, vibration effects are also analyzed. In order to study and compare propagation features of THz links …

Design And Implementation Of A Cyberinfrastructure For Rna Motif Search, Prediction And Analysis, Dongrong Wen

Dissertations

RNA secondary and tertiary structure motifs play important roles in cells. However, very few web servers are available for RNA motif search and prediction. In this dissertation, a cyberinfrastructure, named RNAcyber, capable of performing RNA motif search and prediction, is proposed, designed and implemented.

The first component of RNAcyber is a web-based search engine, named RmotifDB. This web-based tool integrates an RNA secondary structure comparison algorithm with the secondary structure motifs stored in the Rfam database. With a user-friendly interface, RmotifDB provides the ability to search for ncRNA structure motifs in both structural and sequential ways. The second component of …

Approximate String Matching Methods For Duplicate Detection And Clustering Tasks, Oleksandr Rudniy

Dissertations

Approximate string matching methods are utilized by a vast number of duplicate detection and clustering applications in various knowledge domains. The application area is expected to grow due to the recent significant increase in the amount of digital data and knowledge sources. Despite the large number of existing string similarity metrics, there is a need for more precise approximate string matching methods to improve the efficiency of computer-driven data processing, thus decreasing labor-intensive human involvement.

This work introduces a family of novel string similarity methods, which outperform a number of effective well-known and widely used string similarity functions. The new …

Superarmed Glycosyl Donors In Chemical Glycosylation, Hemali Deepthika Premathilake

Dissertations

Only recently has the tremendous biological significance and therapeutic potential of carbohydrates and conjugates thereof (glycoproteins, glycolipids, proteoglycans, etc.) begun to emerge. As the appreciation for the biological roles of carbohydrates a growing demand for efficient and scalable methods towards the synthesis of these challenging molecules has become even more imperative. This has led to the development of a variety of expeditious strategies for oligosaccharide assembly. Amongst these strategies, the so-called armed-disarmed strategy introduced by Fraser-Reid is of particular attractiveness as it allows for chemoselective oligosaccharide synthesis. Recently, the conformational changes as well as the strategic placement of common protecting …

Environmental Literacy Of Seventh-Day Adventist Teachers In The Parochial Schools Of The Florida Conference Of Seventh-Day Adventists, Michael Murdoch

Dissertations

Problem. In the United States, there is an environmental literacy problem. Americans possess limited knowledge about the environment and environmental issues, and they display limited positive action regarding the environment in which they live. Moreover, there is a debate whether a Christian’s interpretation of Gen 1:28 leads either to a lower or to a higher environmental literacy. Does the Seventh-day Adventist teaching community reflect these problems? These are the problems which this dissertation seeks to help solve.

Purpose. The purpose of this study was to attempt to assess the environmental literacy of a group of teachers in Seventh-day …

Analysis Of Illicit Drugs, Their Metabolites And Other Micropollutants In Water By Liquid Chromatography Tandem Mass Spectrometry, Deepika P. Panawennage

Dissertations

The goal of this project is to develop liquid chromatography tandem mass spectrometry (LC/MS/MS) methods for the analysis of different, novel micropollutants in waste water and natural water. Micropollutants are compounds that can exert adverse environmental and human health effects at low concentrations. Most of these compounds include personal care products and pharmaceuticals, such as antibiotics and controlled substances. In the first part of this study, we focused in the analysis of illicit drugs and drug metabolites because these analyses have the potential to serve as markers of drug abuse. We have detected over sixteen different illicit drugs and their …

Synthesis And Photoluminescence (Pl) Of Gold (I) And Silver (I) Metal Complexes With 1-Methylbenzimidazole Diphenylphosphine (Mbdp): Potential Sensing Applications For Volatile Organic Compounds, Darkus Elizabeth Jenkins

Dissertations

Volatile organic compound(s), VOC(s), detection have become a highly demanding area of research due to potential harmful effects to the ecosystem. The search for methods of VOC sensor devices has led to the examination of photoluminescence and photoluminescent materials such as metal complexes. Their luminescent properties markedly with phosphine and/or nitrogen based ligands, bridging ligands, have the ability to accommodate metal atoms with short metal – metal distances. It is of great interest to accomplish short metal interactions as the photoluminescent properties can be altered. We show the synthesis and structural characterization of the bridging ligand, 1-methylbenzimidazole diphenylphosphine. We examined …

Spectroelectrochemical Studies Of The Reductive Intermediates Of Anthraquinone-2,6-Disulfonate In Aqueous Media, Anna Weiss

Dissertations

Reactive intermediates in the reduction of anthraquinone-2,6-disulfonate (AQDS) by dithionite combine to form a transient dimer which has shown to give rise to a series of charge transfer bands in the visible range (600-750 nm). Additional wavelengths associated with these intermediate species have been observed at wavelengths 402, 444 and 510 nm. These transient intermediates are generated as dithionite decomposition products re-oxidize AQDS. Evidence of the dimer was also found in experiments in which reduction of AQDS was achieved electrochemically by the use of a potentiostat. This implies three things: 1. dithionite is not required for dimerization of reactive intermediates; …

Study Of The Vaporization Enthalpies By Correlation-Gas Chromatography, Dmitry Lipkind

Dissertations

The focus of this thesis is on the measurement and collection of thermodynamic and physical property data, including vaporization, fusion, and sublimation enthalpies and vapor pressures of large n-alkanes, nitrogen heterocycles and related compounds by a technique developed in our laboratory referred to as correlation-gas chromatography (C-GC). These thermodynamic data are of importance to several disciplines that include chemical engineering, as well as the pharmaceutical and the petrochemical industries. Vapor pressures of large hydrocarbons are fundamental data required in the petroleum industry to develop thermodynamic models for dealing with crude oil. Environmental chemists and engineers use vapor pressures and vaporization …

Partial Connectivity In Wireless Sensor Networks, Robert Andre Murphy

Dissertations

Given a bounded region of the 2-dimensional plane, a discrete set of nodes is distributed throughout according to a Poisson point process. Given some fixed, finite, real number, two nodes are said to connect and form an edge if their mutual distance is less than this number. Let G be the graph of all such edges over the set of generated nodes and let C be any set of mutually connected nodes. It is shown that there is a critical mutual distance such that at least half of all generated nodes are mutually connected to form a connected cluster. Now, …

The Investigation Of Asphaltene-Naphithenic Acid And Asphaltene-Surface Interactions, David Tristan Heaps

Dissertations

Asphaltenes represent a ubiquitous problem in the oil industry due to their adverse effects on recovery, production, and processing equipment. These problems have affected oil companies throughout the world, resulting in significant financial losses. In order to expand the existing body of knowledge related to asphaltenes, we have examined how the presence of naphthenic acids contributes to the particle aggregation and sedimentation behavior of asphaltene suspensions as well as how the physics and chemistry of a substrate affect asphaltene adsorption/deposition.

The flocculation of asphaltenes in the presence of naphthenic acids was investigated using dynamic light scattering (DLS), near-infrared spectroscopy (NIR), …

Effects Of Molecular Architecture On Fluid Ingress Behavior Of Glassy Polymer Networks, Matthew Blaine Jackson

Dissertations

This manuscript demonstrates the synthesis of glassy polymer network isomers to control morphological variations and study solvent ingress behavior independent of chemical affinity. Well-controlled network architectures with varying free volume average hole-sizes have been shown to substantially influence solvent ingress within glassy polymer networks. Bisphenol-A diglycidyl ether (DGEBA), bisphenol-F diglycidyl ether (DGEBF), Triglycidyl p-aminophenol (pAP, MY0510), Triglycidyl maminophenol (mAP, MY0610), and tetraglydicyl-4,4’-diamino-diphenyl methane (TGDDM, MY721) were cured with 3,3’- and 4,4’-diaminodiphenyl sulfone (DDS) at a stoichiometric ratio of 1:1 oxirane to amine active hydrogen to generate a series of network architectures with an average free volume hole-size (V_h) …

Exploration In Metallic Nitride Fullerenes And Oxometallic Fullerenes: A New Class Of Metallofullerenes, Mary Alice Mackey

Dissertations

Research groups around the world have taken an interest in the synthesis, purification, characterization, and functionalization of Metallic Nitride Fullerenes (MNFs) since their discovery in 1999. This dissertation details the discovery of another new class of molecules—Oxometallic Fullerenes (OMFs).

There are many groups worldwide doing research on MNFs, and there is a large database of published MNF research, but we have had a unique opportunity to fill a research void on OMFs as at present no one else is doing research on these molecules; herein we take molecules that we discover and perform seminal research relating to them. MNF research …

Free Volume Studies Of Various Polymeric Systems Using Positron Annihilation And Pvt-Eos Analyses, Mukul Kaushik

Dissertations

The glass transition phenomenon and free volume behavior below and above the glass transition temperature of various polymeric systems have been investigated. Several novel polymeric systems were considered for this study. Two generations of hyperbranched polyols, H40 and H20, were selected due to large number of hydroxyl groups on the periphery and within the bulk. The effect of hydrogen bonds and molecular weight was related with the glass transition and free volume behavior for the whole range of experimental temperature. The free volume behavior was experimentally studied using PVT and PALS to determine occupied volume, fractional free volume and number …