Physical Sciences and Mathematics Commons^™

Charge, Bonding, And Magneto-Elastic Coupling In Nanomaterials, Qi Sun

Doctoral Dissertations

Phonons are exquisitely sensitive to finite length scale effects in a wide variety of materials because they are intimately connected to charge, structure, and magnetism, and a quantitative analysis of their behavior can reveal microscopic aspects of chemical bonding and spin-phonon coupling. To investigate these effects, we measured infrared vibrational properties of bulk and nanoscale MoS₂ [molybdenum disulfide], MnO [manganese(II) oxide], and CoFe₂O₄ [cobalt iron oxide]. From an analysis of frequencies, oscillator strengths, and high-frequency dielectric constants, we extracted Born and local effective charges, and polarizability for MoS₂ and MnO. For MoS₂ nanoparticles, in …

Local Residents' Experience Of The Coal Ash Spill In Kingston, Tennessee: A Phenomenological Study, Amy Lynn Mathis

Doctoral Dissertations

On December 22, 2008, near Kingston, Tennessee, a Tennessee Valley Authority (TVA) retention pond holding approximately 1.7 million cubic yards of coal fly ash failed, spilling the ash into the nearby Emory River and inundating farms and homes in the Swan Pond community. As a result more than 100 people were permanently displaced from their homes and the clean-up effort is ongoing.

The purpose of this study was to explore the experience of living near Kingston, Tennessee, in the aftermath of the spill. Using existential phenomenology as the guiding research methodology, I interviewed 9 participants from the area and asked …

Condensed Matter From Gauge/Gravity Duality, Jason Edward Therrien

Doctoral Dissertations

Currently strongly coupled systems present the greatest challenge to theoretical physics. For years conventional methods of approach have failed to describe these systems analytically. In recent years it has been shown that there is a duality between weakly coupled and strongly coupled systems, the Gauge Theory/Gravity Duality. In this dissertation I will discuss how the AdS/CFT is used to describe strongly coupled condensed matter systems as well as present the work done by the author and collaborators.

Measurement Of Theta-13 Neutrino Mixing Angle From The Disappearance Of Electron Antineutrinos At The Double Chooz Experiment, Brandon Reed White

Doctoral Dissertations

The measurement of the remaining neutrino-mixing angle, theta-130, is a critical step toward further understanding of neutrino properties and to guide future neutrino oscillation experiments. Double Chooz has a unique opportunity to perform this measurement building on the original CHOOZ reactor anti-neutrino experiment, the experience that set the previous limits on theta-13. In the first phase of Double Chooz, 101 days of data was analyzed with only the far detector operating of a two-detector plan. In this thesis I will describe the design of the low background neutrino detector and the oscillation analysis performed. From the deficiency between the expected …

Charge-Lattice-Spin Interactions In Molecule-Based Magnets, Tatiana Vladimir Brinzari

Doctoral Dissertations

Many of the most attractive properties of multifunctional materials can be traced to the competition between charge, structure, and magnetism. The discovery that these interactions can be tuned with various physical stimuli has accelerated interest in their behavior under extreme conditions. In this dissertation I present a spectroscopic investigation of several model molecule-based magnets under external stimuli of magnetic field and temperature. The compounds of interest include M^II[N(CN)₂]₂ (M=Mn, Co) and [Ru₂(O₂CMe)₄]₃[Cr(CN)₆]. These materials are attractive for their subtle interplay between electronic, magnetic and structural …

Exploring Computational Chemistry On Emerging Architectures, David Dewayne Jenkins

Doctoral Dissertations

Emerging architectures, such as next generation microprocessors, graphics processing units, and Intel MIC cards, are being used with increased popularity in high performance computing. Each of these architectures has advantages over previous generations of architectures including performance, programmability, and power efficiency. With the ever-increasing performance of these architectures, scientific computing applications are able to attack larger, more complicated problems. However, since applications perform differently on each of the architectures, it is difficult to determine the best tool for the job. This dissertation makes the following contributions to computer engineering and computational science. First, this work implements the computational chemistry variational …

Confinement Effects Of Solvation On A Molecule Physisorbed On A Metal Particle, Jacob Fosso Tande

Doctoral Dissertations

We describe and present results of the implementation of the surface and volume polarization for electrostatics~(SVPE) and the iso-density surface solvation models. Unlike most other implementation of the solvation models where the solute and the solvent are described with multiple numerical representation, our implementation uses a multiresolution, adaptive multiwavelet basis to describe both solute and the solvent. This requires reformulation to use integral equations throughout as well as a conscious management of numerical properties of the basis.

Likewise, we investigate the effects of solvation on the static properties of a molecule physisorbed on a spherical particle, modeled as a polarizable …

Parallel For Loops On Heterogeneous Resources, Frederick Edward Weber

Doctoral Dissertations

In recent years, Graphics Processing Units (GPUs) have piqued the interest of researchers in scientific computing. Their immense floating point throughput and massive parallelism make them ideal for not just graphical applications, but many general algorithms as well. Load balancing applications and taking advantage of all computational resources in a machine is a difficult challenge, especially when the resources are heterogeneous. This dissertation presents the clUtil library, which vastly simplifies developing OpenCL applications for heterogeneous systems. The core focus of this dissertation lies in clUtil's ParallelFor construct and our novel PINA scheduler which can efficiently load balance work onto multiple …

Growth And Characterization Of Hexagonal Lu-Fe-O Multiferroic Thin Films, Wenbin Wang

Doctoral Dissertations

In the quest for new types of information processing and storage, complex oxides stand out as one of the most promising material classes. The multiple functionalities of complex oxides naturally arise from the delicate energy balance between the various forms of order (structural, electronic, magnetic). In particular, multiferroic and magnetoelectric oxides which simultaneously exhibit more than one type of ferroic orders have many advantages over existing materials. Widespread practical applications will require a single-phase multiferroic material with a transition temperature that lies considerably above room temperature, large electric and magnetic polarizations, and strong coupling between ferroic orders.

Recently, multiferroic LuFe …

Dynamic Task Execution On Shared And Distributed Memory Architectures, Asim Yarkhan

Doctoral Dissertations

Multicore architectures with high core counts have come to dominate the world of high performance computing, from shared memory machines to the largest distributed memory clusters. The multicore route to increased performance has a simpler design and better power efficiency than the traditional approach of increasing processor frequencies. But, standard programming techniques are not well adapted to this change in computer architecture design.

In this work, we study the use of dynamic runtime environments executing data driven applications as a solution to programming multicore architectures. The goals of our runtime environments are productivity, scalability and performance. We demonstrate productivity by …

Towards A Unification Of Supercomputing, Molecular Dynamics Simulation And Experimental Neutron And X-Ray Scattering Techniques, Benjamin Lindner

Doctoral Dissertations

Molecular dynamics simulation has become an essential tool for scientific discovery and investigation. The ability to evaluate every atomic coordinate for each time instant sets it apart from other methodologies, which can only access experimental observables as an outcome of the atomic coordinates. Here, the utility of molecular dynamics is illustrated by investigating the structure and dynamics of fundamental models of cellulose fibers. For that, a highly parallel code has been developed to compute static and dynamical scattering functions efficiently on modern supercomputing architectures. Using state of the art supercomputing facilities, molecular dynamics code and parallelization strategies, this work also …

Boron And Metal Catalyzed C-C And C-H Bond Formation, Adam Barret Pippin

Doctoral Dissertations

Research efforts focused on the use of boron and metals to form new carbon-carbon and carbon-hydrogen bonds are summarized in this dissertation. Several novel reactions have been developed. These include: the deoxygenation of benzylic alcohols using chloroboranes; alkenylation of benzylic alcohols using boron trichloride; and dialkynlation of aryl aldehydes using dialkynylboron chloride. Numerous applications of these novel reactions have been developed. These include alternate routes to diphenylmethanes and 1,4-diynes from easily prepared dialkynylboron chlorides. In addition, E and Z alkenyl halides can now be prepared using boron trichloride without the use of butyllithium. The stereochemistry of the alkenyl halide can …

Synthesis, Evaluation And Applications Of Biologically Significant Molecules And Their Analogues, Sneha Ashesh Belapure

Doctoral Dissertations

Synthetic chemists are always looking for challenging problems to solve. Design and synthesis of novel molecules that can act as agents of chemical and biological modification are one of the foremost goals of a synthetic chemist. This dissertation describes advances and efforts made in this area.

Obesity is one of the critical problems of the modern age. Molecules that can remediate this condition are highly sought after. The first chapter of this dissertation describes synthetic strategies explored to prepare these valuable natural products along with their structural and stereochemical analogues to study structure and activity relationships (SAR). This method gives …

Structure And Dynamics Of High Temperature Superconductors, Jennifer Lynn Niedziela

Doctoral Dissertations

High temperature superconductivity in iron based compounds has presented a series of complex problems to condensed matter physics since being discovered in 2008. The stalwart basis of condensed matter physics is the “strength in numbers" aspect of crystalline periodicity. Perfect crystalline periodicity has made possible the reduction of the questions of structural and electronic properties to single dimensions, increasing the tractability of these problems. Nevertheless, modern complex materials stretch these assumptions to their limits, and it is at this point where our work starts. Using neutron and x-ray scattering, we have conducted a series of studies on the structural disorder …

Development Of A Novel Technique For Predicting Tumor Response In Adaptive Radiation Therapy, Rebecca Marie Seibert

Doctoral Dissertations

This dissertation concentrates on the introduction of Predictive Adaptive Radiation Therapy (PART) as a potential method to improve cancer treatment. PART is a novel technique that utilizes volumetric image-guided radiation therapy treatment (IGRT) data to actively predict the tumor response to therapy and estimate clinical outcomes during the course of treatment. To implement PART, a patient database containing IGRT image data for 40 lesions obtained from patients who were imaged and treated with helical tomotherapy was constructed. The data was then modeled using locally weighted regression. This model predicts future tumor volumes and masses and the associated confidence intervals based …

Validation Of Weak Form Thermal Analysis Algorithms Supporting Thermal Signature Generation, Elton Lewis Freeman

Masters Theses

Extremization of a weak form for the continuum energy conservation principle differential equation naturally implements fluid convection and radiation as flux Robin boundary conditions associated with unsteady heat transfer. Combining a spatial semi-discretization via finite element trial space basis functions with time-accurate integration generates a totally node-based algebraic statement for computing. Closure for gray body radiation is a newly derived node-based radiosity formulation generating piecewise discontinuous solutions, while that for natural-forced-mixed convection heat transfer is extracted from the literature. Algorithm performance, mathematically predicted by asymptotic convergence theory, is subsequently validated with data obtained in 24 hour diurnal field experiments for …

Evaluation Of Tagging Techniques Gamma-Decay Probabilities Using The Surrogate Method, Timothy Lee Reed

Masters Theses

A detailed analysis of the statistical and discrete [gamma]-decay tagging techniques was conducted using the absolute surrogate and surrogate ratio method (SRM) to obtain the 92Mo(n,[gamma]) cross section in an equivalent neutron energy range of 80 to 880 keV. Excited 93Mo and 95Mo nuclei were populated using (d,p) reactions on 92Mo and 94Mo targets, respectively. The absolute surrogate 92Mo(n,[gamma]) cross sections disagreed with evaluated neutron capture cross section data by as much as a factor of 4 using the statistical tagging approach, whereas the discrete [gamma]-decay tag absolute surrogate cross section disagreed with the evaluated neutron capture cross section by …

Azimuthal Seismic First-Arrival Tomography As A Proxy For Hydraulically Conductive Subsurface Fracture Networks, Matthew Brooks Edmunds

Masters Theses

The Oak Ridge Field Research Center (ORFRC) was established by the Environmental Sciences Division (ESD) at the Oak Ridge National Laboratory (ORNL) in Oak Ridge, TN, in order to study the various biogeochemical processes involved in the remediation as well as natural attenuation of a large contaminant plume that is extant in the vicinity of the ORIFRC. A part of this work has been to characterize the movement of this groundwater/contaminant plume with the use of azimuthal seismic first-arrival tomography (ASFT).

Within the general area of the ORIFRC, a 0-2 m layer of generally isotropic anthropogenic fill and unconsolidated soil …

Synthesis Of Palladium-Based Electrocatalysis—From Pure Metal To Bimetallic Nanoparticles, Haijun Gao

Masters Theses

This thesis focuses on synthesis and characterization of palladium-based nanoparticles. Background information of the research in this thesis is provided in Chapter 1. Preparation and characterization of pure palladium nanoparticles are presented in Chapter 2. A fast and convenient method to prepare ultra small Pd nanoparticles via Pluronic P123 reduction is discussed in detail. Impregnation method and poly method are also studied in this chapter. Chapter 3 reports the studies of these methods to prepare ultra small bimetallic (bimetallic means a mixture of two metals) palladium-based nanoparticles. Oleylamine-mediated method used Pd nanoparticles prepared via P123 reduction as precursor. Ultra small …

Effects Of Prescribed Fire And Habitat On Golden-Winged Warbler (Vermivora Chrysoptera) Abundance And Nest Survival In The Cumberland Mountains Of Tennessee, Katie Lee Percy

Masters Theses

Golden-winged Warbler (Vermivora chrysoptera) populations in Appalachia have declined precipitously over the past 45 years. The primary objective of my study was to monitor the response of Golden-winged Warblers to prescribed fire treatments on reclaimed coal mines in the North Cumberland Wildlife Management Area, Tennessee. Presence-absence surveys were conducted on eight mountain-top study sites and nest searching/monitoring was conducted on two additional sites, 2009-2011. I expanded on previous research of Golden-winged Warbler territory and nest-site selection by determining differences within main effects between used and unused territory plots, as well as used and unused nest-sites. Of my two …

Public Land In A Changing Climate: Planning For An Uncertain Future, Kathleen Marie Hauser

Masters Theses

This thesis investigates the ways in which institutions and actors consider climate change, and how the inclusion of diverse perspectives and challenges in the planning process shapes climate change governance. In particular, I asked how the participants, place-specific contexts, and decision-making processes affect environmental decision-making in Alaska’s National Parks. I discuss the literature on geographical perspectives on climate change, environmental and climate change governance, how uncertainty and risk affect decision-making in the context of climate change, and the history of land use management in the United States. This project incorporates qualitative methods to research the Climate Change Scenario Planning project …

On The Spherical Symmetry Of Perfect-Fluid Stellar Models In General Relativity, Joshua M Brewer

Masters Theses

It is well known in Newtonian theory that static self-gravitating perfect fluids in a vacuum are necessarily spherically symmetric. The necessity of spherical symmetry of perfect-fluid static spacetimes with constant density in general relativity is shown.

Contextualizing The Tipton-Haynes State Historic Site (40wg59): Understanding Landscape Change At An Upland South Farmstead., Daniel Whitaker Howard Brock

Masters Theses

This thesis focuses on a contextual archaeological approach to investigate the historic landscape of the Tipton-Haynes State Historic Site. Tipton-Haynes is a late eighteenth- through twentieth-century upland south farmstead located in Johnson City, TN. Home to two prominent Tennessee families and occupied until acquired by the state in the 1960s, the site has experienced many alterations to the landscape over time. The analysis presented views the landscape as material culture investigated through a multidisciplinary approach including historic research, architectural survey, geophysical survey, dendrochronology, and archaeology. To make sense of the complex nature of the Tipton-Haynes site, multiple methods were used …

Co2 Injection Into A Deep Saline Aquifer: Porosity Measurements, Numerical Modeling, And Costs Associated With Uncertainty Of Petrophysical Parameters, Michael John Gragg

Masters Theses

Anthropogenic levels of atmospheric greenhouse gases, particularly carbon dioxide (CO₂) have increased rapidly over the last several decades and coincide with rising temperatures globally. One possible solution is to capture CO₂ before it is released into the atmosphere by large point sources, such as fossil fuel power plants. Once captured, the CO₂ can be condensed and transported to a storage facility. Of the available options for storage of condensed CO₂, geologic sequestration in deep saline aquifers is considered the most viable option.

Porosity measurements were obtained for nearly 100 core samples of the Knox …

Testing A Novel Technique To Improve Aluminum-26 Accelerator Mass Spectrometry Measurements For Earth Science Applications, Meghan Sarah Janzen

Masters Theses

The measurement of cosmogenic ²⁶Al [aluminum-26] in geological samples by accelerator mass spectrometry (AMS) is typically conducted on Al₂O₃ [aluminum oxide] targets. However, Al₂O₃ is not an ideal source material because it does not form a prolific beam of Al^- [negative atomic aluminum ions] required for measuring low-levels of ²⁶Al. This thesis presents the performance of AlN [aluminum nitride], AlF₃ [aluminum fluoride] and mixed AlN + Al₂O₃ as novel alternative source materials for the analysis of ²⁶Al. A negative ion cesium sputtering source at the Holifield …

Synthesis, Characterization, And Functionalization Of 2-Vinyl-4,4-Dimethylazlactone Brushes To Create Bio-Inspired Materials, Camille Marie Kite

Masters Theses

Functional materials built from polymer scaffolds inspire many potential uses, including as biomaterial surfaces or sensors. In situ functionalization using well-defined polymer “brushes” made by tethering polymer chains to a surface by one of their ends is explored. Specifically, poly(2-vinyl-4,4-dimethylazlactone) (PVDMA) chains, which contain a reactive azlactone ring at each repeat unit, are tethered to a surface to create brushes and these films are functionalized using a variety of small molecules, primarily amines or peptides. Relationships between polymer brush thickness, size of the functionalizing molecule, solution concentration, reaction time, and extent of functionalization were determined through measurements of brush thickness …

On Decision Making: Bayesian And Stochastic Optimization Approaches, Yang Shen

Masters Theses

Decision analysis provides a framework for searching an optimal solution under uncertainties and potential risks. This thesis focuses on two problems arising in transportation engineering and computer sciences, respectively.

First, it is considered a centralized controller which imposes actions on a number of interacting subsystems. Employing an appropriate Markov Decision Process framework, we establish that the Pareto optimal solution of each subsystem will be optimal for the entire system. Synthetic data have been taken into account for verifying this claim.

Next, we focus on a supercomputing problem utilizing a hierarchical Bayesian model. We estimate an optimal solution in order to …

Power Management For Cloud-Scale Data Centers, Yanwei Zhang

Masters Theses

Recent years have seen the rapid growth of large and geographically distributed data centers deployed by Internet service operators to support various services such as cloud computing. Consequently, high electricity bills, as well as negative environmental implications (e.g., CO2 emission and global warming) come along. In this thesis, we first propose a novel electricity bill capping algorithm that not only minimizes the electricity cost, but also enforces a cost budget on the monthly bill for cloud-scale data centers that impact the power markets. Our solution first explicitly models the impacts of the power demands induced by cloud-scale data centers on …

Optimizing Maize Planting Date, Plant Population, And Fertilizer Application Rates For Lesotho Subsistence Farmers, Matthew Ryan Bruns

Masters Theses

Due to perpetually low yields, smallholder farmers throughout Southern Africa plow increasingly large plots of land in an attempt to increase their household food security. However, extensive agriculture further depresses yields because expensive inputs are spread over a larger area, provides little soil cover, and results in high soil erosion rates. To address these challenges, farmers in the Kingdom of Lesotho are beginning to adopt conservation agriculture (CA) systems. Under CA and conventional tillage systems the optimum plant population, planting date, and fertilizer rates are unknown. The effects of field preparation, planting date, weed control strategies, plant populations, and nitrogen …

Math, Minds, Machines, Christopher V. Carlile

Chancellor’s Honors Program Projects

No abstract provided.