Physical Sciences and Mathematics Commons^™

Dynamic Chemical Shift Imaging For Image-Guided Thermal Therapy, Brian A. Taylor

Dissertations & Theses (Open Access)

Magnetic resonance temperature imaging (MRTI) is recognized as a noninvasive means to provide temperature imaging for guidance in thermal therapies. The most common method of estimating temperature changes in the body using MR is by measuring the water proton resonant frequency (PRF) shift. Calculation of the complex phase difference (CPD) is the method of choice for measuring the PRF indirectly since it facilitates temperature mapping with high spatiotemporal resolution. Chemical shift imaging (CSI) techniques can provide the PRF directly with high sensitivity to temperature changes while minimizing artifacts commonly seen in CPD techniques. However, CSI techniques are currently limited by …

Characterization Of Optically Stimulated Luminescent Detectors In Photon & Proton Beams For Use In Anthropomorphic Phantoms, James R. Kerns

Dissertations & Theses (Open Access)

This study investigated characteristics of optically stimulated luminescent detectors (OSLDs) in protons, allowing comparison to thermoluminescent detectors, and to be implemented into the Radiological Physics Center’s (RPC) remote audit quality assurance program for protons, and for remote anthropomorphic phantom irradiations. The OSLDs used were aluminum oxide (Al2O3:C) nanoDots from Landauer, Inc. (Glenwood, Ill.) measuring 10x10x2 mm3. A square, 20(L)x20(W)x0.5(H) cm3 piece of solid water was fabricated with pockets to allow OSLDs and TLDs to be irradiated simultaneously and perpendicular to the beam. Irradiations were performed at 5cm depth in photons, and in the center of a 10 cm SOBP in …

Evaluating Hydroperiod Response In The Rainwater Basin Wetlands Of South-Central Nebraska, Richard D. Wilson

School of Natural Resources: Dissertations, Theses, and Student Research

A collection of wetlands in south-central Nebraska make up a region called the Rainwater Basin. This basin contains closed-basin wetlands formed in loess. The wetlands receive water from precipitation and irrigation runoff. Since the early 1900s, wetland area in the basin has decreased dramatically due to intensive agriculture which either altered or removed the wetlands. The Rainwater Basin wetlands provide many ecological services and thus, should be preserved, but are most noted for the resting, breeding, and feeding habitat they provide for millions of migratory birds that is not provided elsewhere in this region along the continental flyway.

Given the …

Assessing The Effectiveness Of Studio Physics At Georgia State University, Brianna M. Upton

Physics and Astronomy Theses

Previous studies have shown that many students have misconceptions about basic concepts in physics which persist after instruction. It has been concluded that one of the challenges lies in the teaching methodology. To address this, Georgia State University (GSU) has begun teaching studio algebra-based physics. Although many institutions have implemented studio physics, most have done so in calculus-based sequences. Additionally, the unique environment of GSU’s population as a diverse, urban research institution is considered. The effectiveness of the studio approach for this demographic in an algebra-based introductory physics course was assessed. This five-semester pilot study presents demographic survey results and …

Climate Change And Globalization In The Americas: Case Studies Of Mitigation And Adaptation, Mary Finley-Brook, Melissa Haeffner, Charmaine Heslop-Thomas, Elma Montaña, Leah Sprain

Environmental Science and Management Faculty Publications and Presentations

Robin Leichenko and Karen O‘Brien have proposed ―double exposure‖ as a conceptual framework to demonstrate how processes of globalization and global environmental change (GEC) redefine risk and encourage new, interrelated responses to social and ecological transitions (O‘Brien and Leichenko, 2000; Leichenko and O'Brien, 2008). In particular, the concept encourages researchers and policy makers to consider interplay between global climate change and globalization and how this is expressed unevenly across space. After reviewing the ways double exposure has been used in the literature, we consider four case studies to investigate the utility of the framework for analyzing and understanding climate change …

Along-Strike Growth Of The Ostler Fault, New Zealand: Consequences For Drainage Deflection Above Active Thrust, Colin B. Amos, Douglas W. Burbank, Stuart A. L. Read

Geology Faculty Publications

Rarely are geologic records available to constrain the spatial and temporal evolution of thrust‐fault growth as slip accumulates during repeated earthquake events. Here, we utilize multiple generations of dated and deformed fluvial terraces to explore two key aspects of the along‐strike kinematic development of the Ostler fault zone in southern New Zealand over the past ∼100 k.y.: accumulation of fault slip through space and time and fixed‐length thrust growth that results in patterns of drainage diversion suggestive of laterally propagating faults. Along the Ostler fault, surface deformation patterns revealed by topographic surveying of terrace profiles in nine transverse drainages define …

Modified Variational Iteration Method For Second Order Initial Value Problems, Fazhan Geng

Applications and Applied Mathematics: An International Journal (AAM)

In this paper, we introduce a modified variational iteration method for second order initial value problems by transforming the integral of iteration process. The main advantages of this modification are that it can overcome the restriction of the form of nonlinearity term in differential equations and improve the iterative speed of conventional variational iteration method. The method is applied to some nonlinear second order initial value problems and the numerical results reveal that the modified method is accurate and efficient for second order initial value problems.

An Approach For Ensuring Robust Support For Location Privacy And Identity Inference Protection, Chowdhury Sharif Hasan

Master's Theses (2009 -)

The challenge of preserving a user's location privacy is more important now than ever before with the proliferation of handheld devices and the pervasive use of location based services. To protect location privacy, we must ensure k-anonymity so that the user remains indistinguishable among k-1 other users. There is no better way but to use a location anonymizer (LA) to achieve k-anonymity. However, its knowledge of each user's current location makes it susceptible to be a single-point-of-failure. In this thesis, we propose a formal location privacy framework, termed SafeGrid that can work with or without an LA. In SafeGrid, LA …

Testing Quantum Randomness In Single-Photon Polarization Measurements With The Nist Test Suite, David Branning, Matthew Bermudez

Faculty Scholarship

A binary sequence was constructed from 1.7×10⁷ polarization measurements of single photons from a spontaneous parametric downconversion source, under pumping conditions similar to those used in optical quantum cryptography. To search for correlations in the polarization measurement outcomes, we subjected the sequence to a suite of tests developed at the National Institute of Standards and Technology (NIST) for the assessment of algorithmic random-number generators. The bias of the sequence was low enough to allow all fifteen tests to be applied directly to the polarization outcomes without using any numerical unbiasing procedures. No statistically significant deviations from randomness were observed, …

Roger Temam On The Occasion Of His 70th Birthday, Claude Michel Brauner, Danielle Hilhorst, Alain Miranville, Shouhong Wang, Xiaoming Wang

Mathematics and Statistics Faculty Research & Creative Works

No abstract provided.

X-Ray Structure Of Mer-[Mo(Co)3(Pph3)(Κ2-Dppm)], Shishir Ghosh, Shariff E. Kabir, Faranza K. Camellia, Md. Kamal Hossain, Daniel T. Haworth, Sergey V. Lindeman, Tasneem A. Siddiquee, Dennis W. Bennett

Chemistry Faculty Research and Publications

Treatment of [Mo(CO)₃(NCMe)₃] with bis(diphenylphosphino)methane (dppm) and triphenylphosphine (PPh₃) at 50 °C afforded mer-[Mo(CO)₃(PPh₃)(κ²-dppm)] (1) in 55% yield which has been characterized by single crystal X-ray diffraction studies and spectroscopic measurements. Compound 1 crystallizes in the triclinic space group P−1 with a = 10.3449(6), b = 11.1570(6), c = 17.8961(10) Å, β = 80.8400(10)°, Z = 2 and V = 1959.8(2) ų.

Nam Model Forecasts Of Warm Season Quasi-Stationary Frontal Environments In The Central U.S., Shih-Yu (Simon) Wang, Adam J. Clark

Plants, Soils, and Climate Faculty Publications

Using a composite procedure, North American Mesoscale Model (NAM) forecast and observed environments associated with zonally oriented, quasi-stationary surface fronts for 64 cases during July–August 2006–08 were examined for a large region encompassing the central United States. NAM adequately simulated the general synoptic features associated with the frontal environments (e.g., patterns in the low-level wind fields) as well as the positions of the fronts. However, kinematic fields important to frontogenesis such as horizontal deformation and convergence were overpredicted. Surface-based convective available potential energy (CAPE) and precipitable water were also overpredicted, which was likely related to the overprediction of the kinematic …

Applications Of Linear Programming To Coding Theory, Nathan Axvig

Department of Mathematics: Dissertations, Theses, and Student Research

Maximum-likelihood decoding is often the optimal decoding rule one can use, but it is very costly to implement in a general setting. Much effort has therefore been dedicated to find efficient decoding algorithms that either achieve or approximate the error-correcting performance of the maximum-likelihood decoder. This dissertation examines two approaches to this problem.

In 2003 Feldman and his collaborators defined the linear programming decoder, which operates by solving a linear programming relaxation of the maximum-likelihood decoding problem. As with many modern decoding algorithms, is possible for the linear programming decoder to output vectors that do not correspond to codewords; such …

Topology In Composite Spatial Terms, John D. Kelleher, Robert J. Ross

Conference papers

People often refer to objects by describing the object's spatial location relative to another object, e.g. the book on the right of the table. This type of referring expression is called a spatial locative expression. Spatial locatives have three major components: (1) the target object that is being located (the book), (2) the landmark object relative to which the target is being located (the table), and (3) the description of the spatial relationship that exists between the target and the landmark (on the right of ). In English spatial relationships are often described using spatial prepositions. The set of English …

An Empirical Study On The Procedure To Derive Software Quality Estimation Models, Jie Xu, Danny Ho, Luiz Fernando Capretz

Electrical and Computer Engineering Publications

Software quality assurance has been a heated topic for several decades. If factors that influence software quality can be identified, they may provide more insight for better software development management. More precise quality assurance can be achieved by employing resources according to accurate quality estimation at the early stages of a project. In this paper, a general procedure is proposed to derive software quality estimation models and various techniques are presented to accomplish the tasks in respective steps. Several statistical techniques together with machine learning method are utilized to verify the effectiveness of software metrics. Moreover, a neuro-fuzzy approach is …

An Implantable Mosfet Dosimeter Modified To Act As A Fiducial Marker, Joseph S. Dick

Dissertations & Theses (Open Access)

In external beam radiation therapy, it is imperative that the prescribed dose is administered to the correct location and in the correct amount. Though several ex vivo methods of quality assurance are currently employed to achieve this goal, verifying that the correct dose is received within the patient in situ is impossible without the capability of measuring dose inside the patient. Recently, a method of measuring dose delivered within the patient has been developed, an implantable MOSFET dosimeter. This dosimeter is implanted within the patient and records the dose received. Since the dosimeter is implanted in the patient, it could …

The Impact Of Water Harvesting On A Small Watershed In Rural India, Daniel Matz

All Theses

Reliable sources of fresh water are a finite resource across the world. Many countries, including India, face water scarcity due to temporal and spatial variations in precipitation, surface water pollution, and depletion of groundwater resources. In order to combat against water scarcity, the government, non-governmental organizations, researchers, and individuals have attempted to create solutions to the water scarcity problem. One solution, which has become popular throughout India is the construction of water harvestings structures (WHS), small earthen dams built to capture monsoonal runoff on ephemeral streams. Villagers believe these structures have a positive effect on groundwater levels and water availability …

Locating The Accretion Footprint On A Herbig Ae Star: Mwc 480, C A. Grady, K Hamaguchi, G Schneider, B Stecklum, B E. Woodgate, J E. Mccleary, G M. Williger, M L. Sitko, F Menard, Th. Henning, Sean D. Brittain

Publications

Accretion is a fundamental process which establishes the dynamics of the protoplanetary disk and the final properties of the forming star. In solar-type stars, the star–disk coupling is determined by the magnetic field structure, which is responsible for funneling material from the disk midplane to higher latitudes on the star. Here, we use pan-chromatic data for the Herbig Ae star MWC 480 to address whether similar processes occur in intermediatemass stars. MWC 480 has X-ray emission typical of actively accreting Herbig Ae stars, but with ∼10× more photoelectric absorption than expected from optical and FUV data. We consider three sources …

Community Ecology Approaches To Amphibian Conservation, Joanna Hawley

All Theses

Amphibian declines have been observed globally for several decades and populations continue to decline in many areas today. Through an extensive literature review of amphibian `impact studies,' I evaluated the use of multiple species, multiple spatial and temporal scales in an effort to ascertain a more complete, community-wide perspective on the causes of amphibian declines as well as management and conservation implications aimed at reversing these declines. Additionally, I performed multivariate analysis of an amphibian community dataset from southern Maine, USA using a multi-species and scalar approach to identify potentially important environmental variables associated with high levels of amphibian reproductive …

Doping Dependence Of Spin-Lattice Coupling And Two-Dimensional Ordering In Multiferroic Hexagonal Y₁₋ₓluₓmno₃ (0 ≤ X ≤ 1), Junghwan Park, Seongsu Lee, Misun Kang, Kwanghyun Jang, Changhee Lee, Sergey V. Streltsov, Vladimir V. Mazurenko, Maria V. Valentyuk, Julia E. Medvedeva, Takashi Kamiyama, Jegeun Park

Physics Faculty Research & Creative Works

We have examined a complete phase diagram of Y_1-x Lu _xMnO₃ with 0≤x≤1 by using bulk measurements and neutron-diffraction studies. With increasing Lu concentration, Curie-Weiss temperature and Neel temperature are found to increase continuously while the two-dimensional nature of short-range magnetic correlation persists even in the paramagnetic phase throughout the entire doping range. At the same time, the lattice constants and the unit-cell volume get contracted with Lu doping, i.e., chemical pressure effect. This decrease in the lattice constants and the unit-cell volume then leads naturally to an increased magnetic exchange interaction as found in our local …

Analysis Of Optical Spikes Reveals Dynamics Of Aggregates In The Twilight Zone, Nathan Briggs

Electronic Theses and Dissertations

The "biological pump," whereby phytoplankton grow in the surface ocean, aggregate, and sink, is a critical process contributing to global atmospheric CO2 drawdown and provides the vast majority of food for deep ocean and benthic ecosystems. The strength of this pump hinges on the amount of material that stick together to form larger aggregates, the sinking rates of these aggregates, and the rate at which they are consumed as they sink. However, marine aggregates, also called "marine snow," are often fragile and notoriously difficult to sample, their sinking rates are highly variable and difficult to quantify, and their concentrations can …

Polarization And Ellipticity Of High-Order Harmonics From Aligned Molecules Generated By Linearly Polarized Intense Laser Pulses, Anh-Thu Le, R. R. Lucchese, C. D. Lin

Physics Faculty Research & Creative Works

We present theoretical calculations for polarization and ellipticity of high-order harmonics from aligned N₂, CO₂, and O₂ molecules generated by linearly polarized lasers. Within the rescattering model, the two polarization amplitudes of the harmonics are determined by the photo-recombination amplitudes for photons emitted with polarization parallel or perpendicular to the direction of the same returning electron wave packet. Our results show clear species-dependent polarization states, in excellent agreement with experiments. We further note that the measured polarization ellipse of the harmonic furnishes the needed parameters for a "complete" experiment in molecules.

Reducing The Risk Of Human Exposure To Wildlife Diseases, Tyler A. Campbell

United States Department of Agriculture Wildlife Services: Staff Publications

As a professional biologist working for a government agency, I am required to carry a card alerting medical personnel that I may have been exposed to certain zoonotic diseases (animal diseases that can infect man) not routinely considered in differential diagnosis. Some of these pathogens are obscure and seldom heard of, such as monkeypox and Q fever; others more commonly make headlines, such as influenza, West Nile virus, Lyme disease, and Hantavirus Pulmonary Syndrome. Hunters, ranchers, and biologists who work with wildlife have an increased risk of acquiring these diseases directly from animal hosts or their parasites. Here are some …

Temporal And Spatial Variations Of Ions, Isotopes And Agricultural Contaminants In Surface Waters And Groundwater Of Nebraska's Rainwater Basin Wetland Region, Sarah E. Foster

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

The wetlands of south-central Nebraska’s Rainwater Basin region are considered of international importance as a habitat for millions of migratory birds, but are being endangered by agricultural practices. The Rainwater Basin extends across 17 counties and covers 4,000 square miles. The purpose of this study was to assemble baseline chemical data for several representative wetlands across the Rainwater Basin region, and determine the use of these chemical data for investigating groundwater recharge.

Eight representative wetlands were chosen across the Rainwater Basin to monitor surface and groundwater chemistry. At each site, a shallow well and deep well were installed and sampled …

Local Radial Basis Function Methods For Solving Partial Differential Equations, Guangming Yao

Dissertations

Meshless methods are relatively new numerical methods which have gained popularity in computational and engineering sciences during the last two decades. This dissertation develops two new localized meshless methods for solving a variety partial differential equations.

Recently, some localized meshless methods have been introduced in order to handle large-scale problems, or to avoid ill-conditioned problems involving global radial basis function approximations. This dissertation explains two new localized meshelss methods, each derived from the global Method of Approximate Particular Solutions (MAPS). One method, the Localized Method of Approximate Particular Solutions (LMAPS), is used for elliptic and parabolic partial differential equations (PDEs) …

Design, Synthesis, And Polymerization Of Novel Heterocyclic Monomers As Precursors For Functional Polyester, Poly(Ester Amide)S And Polyamides, Eylem Tarkin-Tas

Dissertations

The research presented in this dissertation involves the synthesis and polymerization of heterocyclic monomers which pave the way to biodegradable polyester nanocomposites, functional polyesters or poly(ester amide)s, functional polyamides and supramolecular polymers. The key monomers are ε-caprolactone, γ-acetamido-ε- caprolactone, γ-ethylene ketal-ε-caprolactam and α-amino-ε-caprolactam.

Poly(ε-caprolactone) organo-modified montmorillonite nanocomposites were prepared by in-situ polymerization using dibutyltin dimethoxide as initiator/catalyst. The montmorillonite was first modified with 1-decyl-2-methyl-3-(11-hydroxyundecyl)- imidazolium cation. The hydroxyl functionality was used for not only initiating polymer chains from the surface of the clay platelets but also for grafting polymer chains to the surface by acting as a reversible chain transfer …

Studies Of Meson Mass Spectra In The Context Of Quark-Antiquark Bound States, Mallika Dhar

Dissertations

This dissertation deals with the computation of meson mass spectra in the context of quarkantiquark (q ¯ q) bound-state. Traditionally the q ¯ q bound-state problem is treated by solving the non-relativistic Schrödinger equation in position representation with a linear confining potential and a Coulomb-like attractive potential. For high energy, relativistic kinematics is necessary. It is well known that relativistic kinematics cannot be treated properly in position representation, but it can easily be handled in momentum representation. On the other hand, the linear potential and Coulomb-like potential have singularities in momentum-space and complicated subtraction procedure is necessary to treat the …

The Mechanical Stress–Strain Properties Of Single Electrospun Collagen Type I Nanofibers, Christine C. Helms, Corentin Coulais, Martin Guthold

Physics Faculty Publications

Knowledge of the mechanical properties of electrospun fibers is important for their successful application in tissue engineering, material composites, filtration and drug delivery. In particular, electrospun collagen has great potential for biomedical applications due to its biocompatibility and promotion of cell growth and adhesion. Using a combined atomic force microscopy (AFM)/optical microscopy technique, the single fiber mechanical properties of dry, electrospun collagen type I were determined. The fibers were electrospun from a 80 mg ml⁻¹ collagen solution in 1,1,1,3,3,3-hexafluro-2-propanol and collected on a striated surface suitable for lateral force manipulation by AFM. The small strain modulus, calculated from three-point …

Parallel √3-Subdivision With Animation In Consideration Of Geometric Complexity, Stephen Cooney

All Theses

We look at the broader field of geometric subdivision and the emerging field of parallel computing for the purpose of creating higher visual fidelity at an efficient pace. Primarily, we present a parallel algorithm for √3-Subdivision. When considering animation, we find that it is possible to do subdivision by providing only one variable input, with the rest being considered static. This reduces the amount of data transfer required to continually update a subdividing mesh. We can support recursive subdivision by applying the technique in passes. As a basis for analysis, we look at performance in an OpenCL implementation that utilizes …

Spectroscopic Abundances And Membership In The Wolf 630 Moving Group, Eric J. Bubar, Jeremy R. King

Publications

The concept of kinematic assemblages evolving from dispersed stellar clusters has remained contentious since Eggen’s initial formulation of moving groups in the 1960s. With high-quality parallaxes from the Hipparcos space astrometry mission, distance measurements for thousands of nearby, seemingly isolated stars are currently available. With these distances, a high-resolution spectroscopic abundance analysis can be brought to bear on the alleged members of these moving groups. If a structure is a relic of an open cluster, the members can be expected to be monolithic in age and abundance in as much as homogeneity is observed in young open clusters. In this …