Physical Sciences and Mathematics Commons^™

Towards Catalytic Oxidative Depolymerization Of Lignin, Justin K. Mobley

Theses and Dissertations--Chemistry

Lignin is one of the most abundant and underutilized biopolymers on earth. Primarily composed on three monolignol units (sinapyl, coniferyl, and p-coumaryl alcohol), lignin is formed through a radical pathway resulting in an assortment of linkages, of which the β-O-4 linkage is the most prevalent (up to 60% in some hardwood species). In planta, lignin plays an important role in water transport and in protecting plants from chemical and biological attack. Traditional attempts to depolymerize lignin have focused on the cleavage of β-O-4 linkages via thermal or reductive routes. However these pathways lead to low-value, unstable product mixtures. Moreover, …

Towards An Understanding Of Pharmacologically Induced Intracellular Changes In Nicotinic Acetylcholine Receptors: A Fluorescence Microscopy Approach, Ashley M. Loe

Theses and Dissertations--Chemistry

Upregulation of nicotinic acetylcholine receptors (nAChRs) is a well-documented response to chronic nicotine exposure. Nicotinic acetylcholine receptors are pentameric ligand-gated ion channels consisting of alpha (α2-10) and beta (β2-4) subunits. Nicotine, an agonist of nAChRs, alters trafficking and assembly of some subtypes of nAChRs, leading to an increase in expression of high sensitivity receptors on the plasma membrane. These physiological changes in nAChRs are believed to contribute to nicotine addiction, although the mechanism of these processes has not been resolved. Recently, many studies have converged on the idea that nicotine induces upregulation by an intracellular mechanism. In this dissertation, expression …

Organometallic Materials: Ferroceno[C]Thiophenes And 1,2-Bisthienylmetallocenes, Surya R. Banks

Theses and Dissertations--Chemistry

Development of synthetic routes toward two general organometallic frameworks was undertaken. The first project involved synthetic attempts of substituted and unsubstituted ferroceno[c]thiophene while the second one was the synthesis of 1,2-dithienylmetallocenes. The long-term goal of this work is to lay the foundations for study of electronic, electrochromic, redox, and optical properties of thiophene-based materials integrated with organometallic systems such as ferrocene, ruthenocene and cymantrene. The synthetic pathway for the target molecule in the first project involved converting 1,2-bis(hydroxymethyl)ferrocene to 1,2-bis(thiouroniummethyl)ferrocene with thiourea under acidic conditions. Refluxing the salt in base followed by acidification resulted in 1,2-bis(mercaptomethyl)ferrocene, which is …

Using Conventional And In Situ Transmission Electron Microscopy Techniques To Understand Nanoscale Crystallography, Bethany M. Hudak

Theses and Dissertations--Chemistry

Transmission electron microscopy (TEM) is a powerful tool for studying solidstate crystalline systems. With the advances in aberration correction, monochromation, and in situ capabilities, these microscopes are now more useful for addressing fundamental materials chemistry problems than ever before. This dissertation will illustrate the ways in which I have been using high-resolution imaging and in situ heating in the TEM during my Ph.D. research to investigate unique solid state chemistry questions.

This dissertation will focus on four unique crystal systems: thermoelectric skutterudite crystals, vapor-liquid-solid (VLS) grown nanowires, and hafnium dioxide nanorods. Although these systems are very different from one another, …

Patterns Of Abundance And Community Dynamics In Atlantic Coastal Sharks, Cassidy Peterson

Dissertations, Theses, and Masters Projects

No abstract provided.

Optical Characterization Of Interface Magnetization In Multifunctional Oxide Heterostructures, Fan Fang

Dissertations, Theses, and Masters Projects

Multifunctional oxides attract much attention recently. The strong correlated electron system involves the notable properties of colossal magnetoresistance, ferroelectric tunneling and spin transport, with the coupling of electron, spin and orbital degrees of freedom. their rich functional behavior is of potential use for nanoelectronics and data storage. Particularly interesting are the mulitferroic materials, which exhibit simultaneously electric and magnetic ordering properties. Understanding the interface coupling mechanism of these two order parameters are critical to future development of high-performance spintronic devices. The goal of this dissertation is to elucidate the interfacial magnetoelectric (ME) coupling with optical characterization method -- magnetization-induced second-harmonic …

Modeling Phytoplankton Community Response To Nutrient Loading And Climate Change In A Shallow Temperate Estuary, Sara Aimee Blachman

Dissertations, Theses, and Masters Projects

Phytoplankton account for at least half of all primary production in estuarine waters and are at the center of biogeochemical cycles and material budgets. Environmental managers use water column chlorophyll-a (chl-a) concentrations as a basic water quality indictor, as the problems of eutrophication and hypoxia are intrinsically linked to excessive phytoplankton growth. Evidence suggests that the distribution and frequency of harmful algal blooms may be increasing worldwide. For the most part, phytoplankton communities follow a standard seasonal pattern, with specific groups dominating the assemblage during the time of year when environmental conditions correspond to their requisites for growth. However, climate …

Modeling Flocculation And Deflocculation Processes Of Cohesive Sediments, Xiaoteng Shen

Dissertations, Theses, and Masters Projects

The transport and fate of cohesive sediments are responsible for many engineering, environmental, economic and policy issues that relate to, for example, siltation and dredging in navigation channels, water quality, water turbidity, pollutant transports, and biological ecosystem responses. Our current understanding, however, is insufficient to conduct accurate quantitative predictions of these processes. This is because the cohesive particles in natural waters will flocculate, which determines the settling, and thus the deposition behaviors. The simulation of flocculation processes is a primary challenge since the time variation of Floc Size Distribution (FSD) is controlled by a partial differential equation that also contains …

Methyl And T-Butyl Group Rotation In A Molecular Solid: 1h Nmr Spin-Lattice Relaxation And X-Ray Diffraction, Peter A. Beckmann, Curtis E. Moore, Arnold L. Rheingold

Physics Faculty Research and Scholarship

We report solid state 1H nuclear magnetic resonance spin-lattice relaxation experiments and X-ray diffractometry in 2-t-butyldimethylsilyloxy-6-bromonaphthalene. This compound offers an opportunity to simultaneously investigate, and differentiate between, the rotations of a t-butyl group [C(CH3)3] and its three constituent methyl groups (CH3) and, simultaneously, a pair of 'lone' methyl groups (attached to the Si atom). The solid state 1H relaxation experiments determine activation energies for these rotations. We review the models for the dynamics of both 'lone' methyl groups (ones whose rotation axes do not move on the NMR time scale) and models for the dynamics of the t-butyl group and …

Observations Of The High Vibrational Levels Of The B′′B̄ 1Σ+U State Of H2, A. M. Chartrand, W. Duan, R. C. Ekey, Elizabeth Mccormack

Physics Faculty Research and Scholarship

Double-resonance laser spectroscopy via the E F ¹Σ⁺_g, v' = 6, J' = 0–2 state was used to probe the high vibrational levels of the B′′B̄ ¹Σ⁺_u state of molecular hydrogen. Resonantly enhanced multiphotonionization spectra were recorded by detecting ion production as a function of energy using a time of flight mass spectrometer. New measurements of energies for the v = 51–66 levels for the B00B ̄ state of H2 are reported, which, taken with previous results, span the v = 46–69 vibrational levels. Results for energy levels are compared to theoretical close-coupled …

1h And 19f Spin-Lattice Relaxation And Ch3 Or Cf3 Reorientation In Molecular Solids Containing Both H And F Atoms, Peter A. Beckmann, Andrew L. Rheingold

Physics Faculty Research and Scholarship

The dynamics of methyl (CH3) and fluoromethyl (CF3) groups in organic molecular (van der Waals) solids can be exploited to survey their local environments. We report solid state 1H and 19F spin-lattice relaxationexperiments in polycrystalline 3-trifluoromethoxycinnamic acid, along with an X-ray diffraction determination of the molecular and crystal structure, to investigate the intramolecular and intermolecular interactions that determine the properties that characterize the CF3 reorientation. The molecule is of no particular interest; it simply provides a motionless backbone (on the nuclear magnetic resonance (NMR) time scale) to investigate CF3reorientation occurring on the NMR time scale. The effects of 19F–19F and …

Effects Of Epichloë Coenophiala−Tall Fescue Symbiosis On Plant-Microbe-Soil Interactions In A Temperate Pasture, Lindsey C. Slaughter

Theses and Dissertations--Plant and Soil Sciences

Plants interact in myriad ways with microorganisms to influence ecosystem processes such as nutrient cycling, which can regulate ecosystem response to global change. One important plant-microbe symbiosis occurs between cool-season grasses and asexual fungal Epichloë endophytes, such as tall fescue (Schedonorus arundinaceus) and Epichloë coenophiala. Because the common toxic strain of the endophyte (CTE) harms grazing livestock, non-livestock toxic endophyte (NTE) strains have been developed and are increasingly deployed in pastures. Little is known about how these symbioses impact other plant-microbe interactions and microbe-mediated soil processes in grassland ecosystems. I conducted three studies to determine how E. …

Photoassisted Generation Of Complex N, O, S Polyheterocycles, Weston James Umstead

Electronic Theses and Dissertations

This research set out to continue the exploration and diversification of excited state o-azaxylylene cycloadditions, utilizing both pre-photochemical and post-photochemical modifications.

Pre-photochemical modifications came through the addition of heteroatoms, namely nitrogen and oxygen, to the tether that links the unsaturated photopendant to the photogenerated o-azaxylylene. Photochemistry resulted in the formation of new, interesting N, O, S polyheterocycles.

Post-photochemical modifications took place through several different cycloaddition reactions, including a [4+2] hetero-Diels Alder reaction, a [4+2] Povarov cyclization, a [3+2] nitrile oxide addition, and a [3+2] nitrone cyclization. These reactions were applied first to a model system, and then to …

A Comparison Between Propensity Score Matching, Weighting, And Stratification In Multiple Treatment Groups: A Simulation Study, Priyalatha Govindasamy

Electronic Theses and Dissertations

The application of propensity score techniques (matching, stratification, and weighting) with multiple treatment levels are similar to those used in binary groups. However, given that the application of propensity scores in multiple treatment groups is new, factors affecting the performance of matching, stratification, and weighting in multiple treatment groups are less explored. Therefore, this study was conducted to determine the performance of different propensity score techniques with multiple treatment groups under various circumstances. Specifically, the study focused on examining how the three propensity score corrective techniques perform in estimating treatment effects under (1) overt and (2) hidden types of selection …

Modeling Of Structural Relaxation By A Variable-Order Fractional Differential Equation, Su Yang

Theses and Dissertations

In physical point of view, relaxation usually describes the return from a perturbed system into equilibrium and each process has its own characteristic relaxation time. In 1946, Tool first formulated the notion of fictive temperature to characterize the structure of a glass-forming melt. Since then, people used to simulate structural relaxation by first order model. Since fractional-based models have not widely applied in modeling the fictive temperature, I want to explore the the possibility of modeling structural relaxation by fractional differential equation.

In this thesis, I will first introduce the definitions of two different kinds of fractional derivatives: Riemann-Liouville fractional …

Optimisation Of Anodic Oxidation Of Aluminium For Enhanced Adhesion And Corrosion Properties Of Sol-Gel Coatings., Michael Whelan, Tobin Edmond, John Cassidy, J. Colreavy, Brendan Duffy

Articles

The anodising process for clad and bare AA2024-T3 has been optimised as a surface preparation technique prior to sol-gel coating deposition. The combination of anodised aluminium surfaces and organically functionalised sol-gel chemistry have been investigated to impart elevated corrosion resistance and increased mechanical properties to the aluminium metal. A duplex anodising process has been developed to utilise the natural corrosion resistance properties of sulphuric acid anodising with the adhesion and hosting properties of phosphoric acid anodising. The novel anodising process and sol-gel sealed surfaces have been characterised using field emission scanning electron microscopy, energy dispersive x-ray spectroscopy. Performance of the …

Tablet Usage In Secondary Mathematics Education And Recommendations For Improving Its Effectiveness In The Classroom, Meghan T. Dwyer

Honors Theses

As part of my honor's thesis project at Assumption College, I have been researching the ways that teachers are currently using tablets in their secondary mathematics classrooms. My thesis compares the benefits and drawbacks of having tablets in classrooms, tablets for every student, or no tablets at all. In the spring, I collected survey feedback from mathematics teachers in four different local school districts. I analyzed the data in order to determine the ways tablets are being used in classrooms, the reasons preventing teachers from fully integrating tablets into their instruction, the impacts training has had on tablet use, and …

An Improved Tight-Binding Model For Phosphorene, Kursti Delello

Honors Undergraduate Theses

The intent of this thesis is to improve upon previously proposed tight-binding models for one dimensional black phosphorus, or phosphorene. Previous models offer only a qualitative analysis of the band structure of phosphorene, and fail to fully realize critical elements in the electronic band structure necessary for transport calculations. In this work we propose an improved tight-binding model for phosphorene by including up to eight nearest-neighbor interactions. The efficacy of the model is verified by comparison with DFT-HSE06 calculations, and the anisotropy of the effective masses in the armchair and zigzag directions is considered.

Atmospheric, Orbital, And Eclipse-Depth Analysis Of The Hot Jupiter Hat-P-30-Wasp-51ab, Andrew Sd Foster

Honors Undergraduate Theses

HAT-P-30-WASP-51b is a hot-Jupiter exoplanet that orbits an F star every 2.8106 days at a distance of 0.0419 AU. Using the Spitzer Space Telescope in 2012 (Spitzer Program Number 70084) we observed two secondary eclipses at 3.6 and 4.5 μm. We present eclipse-depth measurements of 0.177 ± 0.018 % and 0.247 ± 0.024 % and estimate the infrared brightness temperatures to be 1990 ± 110 K and 2080 ± 130 K for these two channels, respectively, from an analysis using our Photometry for Orbits, Eclipses, and Transits (POET) pipeline. These may be grazing eclipses. We also refine its orbit using …

The Statistics And Mathematics Of High Dimension Low Sample Size Asymptotics, Dan Shen, Haipeng Shen, Hongtu Zhu, J S Marron

Mathematics and Statistics Faculty Publications

The aim of this paper is to establish several deep theoretical properties of principal component analysis for multiple-component spike covariance models. Our new results reveal an asymptotic conical structure in critical sample eigendirections under the spike models with distinguishable (or indistinguishable) eigenvalues, when the sample size and/or the number of variables (or dimension) tend to infinity. The consistency of the sample eigenvectors relative to their population counterparts is determined by the ratio between the dimension and the product of the sample size with the spike size. When this ratio converges to a nonzero constant, the sample eigenvector converges to a …

A Soliton Hierarchy Associated With A Spectral Problem Of 2nd Degree In A Spectral Parameter And Its Bi-Hamiltonian Structure, Yuqin Yao, Shoufeng Shen, Wen-Xiu Ma

Mathematics and Statistics Faculty Publications

Associated with s͠o(3,R) , a new matrix spectral problem of 2nd degree in a spectral parameter is proposed and its corresponding soliton hierarchy is generated within the zero curvature formulation. Bi-Hamiltonian structures of the presented soliton hierarchy are furnished by using the trace identity, and thus, all presented equations possess infinitely commuting many symmetries and conservation laws, which implies their Liouville integrability.

A Usability And Learnability Case Study Of Glass Flight Deck Interfaces And Pilot Interactions Through Scenario-Based Training, Thomas James De Cino

CCE Theses and Dissertations

In the aviation industry, digitally produced and presented flight, navigation, and aircraft information is commonly referred to as glass flight decks. Glass flight decks are driven by computer-based subsystems and have long been a part of military and commercial aviation sectors. Over the past 15 years, the General Aviation (GA) sector of the aviation industry has become a recent beneficiary of the rapid advancement of computer-based glass flight deck (GFD) systems.

While providing the GA pilot considerable enhancements in the quality of information about the status and operations of the aircraft, training pilots on the use of glass flight decks …

A Study Of The Success Of Group Formation In Virtual Teams Using Computer-Mediated Communications, Eliel Melón-Ramos

CCE Theses and Dissertations

In the digital domain, virtual teams within organizations and corporations are becoming common. Restructuring an organization or corporation is vital because competition and globalization are increasing. In this era of globalization, distributed working groups need to develop a competitive advantage in these ever-changing environments. Historically, teams had experienced problems stemming from geographical and temporal limitations. With the increase of technology in telecommunications, organizations are increasingly forming virtual teams, which have become critical to the survival of nearly any corporate entity.

Virtual teams have some of the same problems that regular teams have. One of the key challenges is the method …

An Empirical Assessment Of Employee Cyberslacking In The Public Sector, Wilnelia Hernández

CCE Theses and Dissertations

With the increasing use of the Internet, new challenges are presented to employees in the workplace. Employees spend time during work hours on non-work related activities including visiting e-commerce Websites, managing personal email accounts, and engaging in e-banking. These types of actions in the workplace are known as cyberslacking. Cyberslacking affects the employees’ productivity, presents legal concerns, and undermines the security of the organization’s network. This research study addressed the problem of cyberslacking in the public sector, by assessing the ethical severity of cyberslacking activities, as well as how employees perceived that the frequency of such activities occurred by their …

Enhanced Method Call Tree For Comprehensive Detection Of Symptoms Of Cross Cutting Concerns, Saleem Obaidullah Mir

CCE Theses and Dissertations

Aspect oriented programming languages provide a new enhanced composition mechanism between the functional sub units as compared to earlier non aspect oriented languages. For this reason the refactoring process requires a new approach to the analysis of existing code that focuses on how the functions cross cut one another. Aspect mining is a process of studying an existing program in order to find these cross cutting functions or concerns so they may be implemented using new aspect oriented constructs and thus reduce the complexity of the existing code. One approach to the detection of these cross cutting concerns generates a …

An Investigation Of Socio-Technical Components Of Knowledge Management System (Kms) Usage, Noel Wint Jr.

CCE Theses and Dissertations

Existing literature indicates that although both academics and practitioners recognize knowledge management (KM) as a source of competitive advantage, users are not always willing to use a knowledge management system (KMS). Because of the social nature of knowledge transfer, a KMS can be considered a socio-technical system. Many explanations have been presented for this failure to utilize the KMS. These explanations include a number of the socio-technical factors relating to people, processes, and technologies. While these factors may have significant explanatory power when examined independently, existing studies have not sufficiently addressed the interactions among all three socio-technical factors or their …

Electronic Medical Records (Emr): An Empirical Testing Of Factors Contributing To Healthcare Professionals’ Resistance To Use Emr Systems, Emmanuel Patrick Bazile

CCE Theses and Dissertations

The benefits of using electronic medical records (EMRs) have been well documented; however, despite numerous financial benefits and cost reductions being offered by the federal government, some healthcare professionals have been reluctant to implement EMR systems. In fact, prior research provides evidence of failed EMR implementations due to resistance on the part of physicians, nurses, and clinical administrators. In 2010, only 25% of office-based physicians have basic EMR systems and only 10% have fully functional systems. One of the hindrances believed to be responsible for the slow implementation rates of EMR systems is resistance from healthcare professionals not truly convinced …

Patient Portals: Achieving Technology Acceptance And Meaningful Use In Independent Physician-Managed Practices, Kimberly W. Bartholomew

CCE Theses and Dissertations

As the bulk of medical health records shift from paper-based file systems to electronic formats, the promise of the transformation process called healthcare reform included adding efficiencies to medical practice workflows, lower costs, improved quality of care and most important, and the freeing of patient information from traditional propriety silos. With this incoming largess of protected health information data now viewable through online patient portals, patients can be empowered to become educated and active in their own health care decisions, but only if they have admission to their information. A digital divide currently exists in many medical practices where only …

Use Of Student Created Video Podcasts To Promote Foreign Language Grammar Acquisition In Middle School, Sergio Parra

CCE Theses and Dissertations

The use of video podcasts in education has emerged as a phenomenon that has gained a considerable amount of attention over the last few years. Although video podcasting is becoming a well-established technology in higher education, new multimedia instructional strategies such as student-created video podcasts in grades K-12 are under-researched.

The study investigated the effects of video podcasts created by students to promote foreign language grammar acquisition at the middle school level and find how students described such experience. The current investigation was conducted by using the explanatory sequential design, which is a mixed methods research design that occurs in …

A Study Of Data Sharing Practices Within Scholarly Research Communities, Mary Harward

CCE Theses and Dissertations

Recent literature acknowledges the importance of data and effective data management strategies to facilitate collaboration between disciplines of research. Likewise, understanding the policies and practices that support data sharing is a growing area of research in the fields of information and social studies of science. Shared data allow researchers to build on fellow researchers’ work to enrich and facilitate advancements in science. While much has been written to identify the elements that adversely affect data sharing in scholarly research, a definitive framework remains unclear. Several theories have been presented to explain this shortfall; however, the reasons are highly diverse. Some …