Physical Sciences and Mathematics Commons^™

Gravitational Waves From Perturbed Kerr Black Holes: Two Investigations, Zhongyang Zhang

Electronic Theses and Dissertations

This thesis includes two main projects. The first project is a study of the effect of black hole spin on the accuracy of the post-Newtonian approximation. We focus on the gravitational energy produced by the quasicircular, equatorial, extreme mass-ratio inspiral of a compact object into a Kerr black hole of mass M and spin J. For a given dimensionless spin a ≡ J/M2 (in geometrical units G = c = 1 ), the energy flux depends only on the orbital velocity v or (equivalently) on the Boyer-Lindquist orbital radius r. We investigate the formal region of validity of the Taylor …

Backscatter And Attenuation Properties Of Mammalian Brain Tissues, Pushpani Vihara Wijekularatne

Electronic Theses and Dissertations

Traumatic Brain Injury (TBI) is a comcategory of brain injuries, which contributes to a substantial number of deaths and permanent disability all over the world. Ultrasound technology plays a major role in tissue characterization due to its low cost and portability that could be used to bridge a wide gap in the TBI diagnostic process. This research addresses the ultrasonic properties of mammalian brain tissues focusing on backscatter and attenuation. Orientation dependence and spatial averaging of data were analyzed using the same method resulting from insertion of tissue sample between a transducer and a reference reflector. Apparent Backscatter Transfer Function …

Method Development Using Laser Ablation And Solution Icpms And Their Application In Environmental Science And Forensic Provenance Studies, Kaixuan Bu

Electronic Theses and Dissertations

Inductively coupled plasma mass spectrometry (ICPMS) is an analytical technique that can be used to determine multiple elements and isotope ratios in a wide variety of samples. In this work, four projects are described that involve the method development using laser ablation (LA) and solution-based ICPMS and their application in environmental science and forensic (provenance) investigations. In the first project, plutonium (Pu) concentrations and 240Pu/ 239Pu atom ratios were measured in kelp, lichen, aquatic moss, and horse mussel collected on or near Amchitka Island, a former nuclear test in Alaska, and at a background site. The Pu in terrestrial and …

Studies Of Mercury In Water, Sediment, And Fish In Mississippi: Concentrations, Speciation, Cycling, And Isotopic Composition, Garry Brown

Electronic Theses and Dissertations

The goal of this project is to better understand the biogeochemical cycle of mercury (Hg) in Mississippi to aid those managing the resources and developing related policy. To that end, Hg levels were determined in a total of 202 fish from Enid, Sardis and Grenada Lakes; Enid and Grenada have fish consumption advisories due to Hg. In addition, total-Hg and methylmercury (MeHg) levels were determined in the inflow and outflows from Enid and Sardis Lakes and in bottom sediment and suspended solids in Enid Lake. Potential sources of Hg to Enid Lake were investigated, including precipitation and runoff from urban, …

Well-Covered Graphs, Unique Colorability, And Covering Range, Wanda Renea Payne

Electronic Theses and Dissertations

A graph is called well-covered if all of its maximal independent sets have the same cardinality. We give a characterization of well-covered k-trees. A graph is said to be uniquely χ-colorable if, modulo permutations of colors, it has exactly one proper χ-coloring. The k-trees with at least k+1 vertices are minimal uniquely (k +1)-colorable, i.e., they have the minimal number of edges necessary for uniquely (k+1)-colorable graphs. We introduce the k-frames, a new class of minimal uniquely (k+1)-colorable graphs that generalizes the k-trees.

The covering range of a graph is the difference between the cardinality of a largest maximal independent …

Trophic State Monitoring Of Lakes And Reservoirs Using Remote Sensing, Michelle Aten

Electronic Theses and Dissertations

Lakes and reservoirs are important resources that provide water for critical needs, such as drinking water, agriculture, recreation, fisheries, wildlife, and other uses. However, there is increasing concern that anthropogenic eutrophication threatens the usability of these natural resources. Therefore, this research investigates these complex hydrologic ecosystems and recommends a methodology for monitoring the trophic state of lakes and reservoirs using remote sensing data. The Mississippi Department of Environmental Quality provided in situ data for seven Mississippi lakes including, Arkabutla, Bay Springs, Enid, Grenada, Okatibbee, Ross Barnett, and Sardis lakes. This research explored the relationships between the Secchi depth (SD), chlorophyll-a …

Synthesis, Characterization And Application Of Pt Complexes With Pincer Ccc-Bis(Nhc) Ligands, Xiaofei Zhang

Electronic Theses and Dissertations

The unique metallation/transmetallation route for the synthesis of CCC-bis(NHC) pincer ligand supported transition metal complexes was extended to Pt. Several platinum complexes were synthesized. The identity of these complexes was confirmed through multiple technologies, including nuclear magnetic resonance spectroscopy, mass spectroscopy, elemental analysis, thermal analysis, and X-ray crystallography. The intriguing photophysical and thermal properties of these complexes are reported. These complexes were believed to be congeners of materials for organic light emitting diodes (OLEDs).

On Binary And Regular Matroids Without Small Minors, Kayla Davis Harville

Electronic Theses and Dissertations

The results of this dissertation consist of excluded-minor results for Binary Matroids and excluded-minor results for Regular Matroids. Structural theorems on the relationship between minors and k-sums of matroids are developed here in order to provide some of these characterizations. Chapter 2 of the dissertation contains excluded-minor results for Binary Matroids. The first main result of this dissertation is a characterization of the internally 4-connected binary matroids with no minor that is isomorphic to the cycle matroid of the prism+e graph. This characterization generalizes results of Mayhew and Royle [18] for binary matroids and results of Dirac [8] and Lovász …

Large Eddy Simulation Of Surface Pressure Fluctuations Generated By Elevated Gusts, Jericho Erin Cain

Electronic Theses and Dissertations

Wind gusts cause substantial damage to wind turbines. If these damaging winds could be detected prior to their interaction with the turbine, the turbine rotor can be decoupled from the generator and gearing system to prevent damage during the gust event. This would significantly reduce wind turbine repair costs. Wind gusts can also create unsafe conditions for aircraft landing. A ground based detection system that monitored elevated wind gusts can provide new information for pilots to use when determining whether or not it is safe to land. In addition, the ability to monitor elevated gust events would provide a new …

Partial Replica Location And Selection For Spatial Datasets, Yun Tian

Electronic Theses and Dissertations

As the size of scientific datasets continues to grow, we will not be able to store enormous datasets on a single grid node, but must distribute them across many grid nodes. The implementation of partial or incomplete replicas, which represent only a subset of a larger dataset, has been an active topic of research. Partial Spatial Replicas extend this functionality to spatial data, allowing us to distribute a spatial dataset in pieces over several locations. We investigate solutions to the partial spatial replica selection problems. First, we describe and develop two designs for an Spatial Replica Location Service (SRLS), which …

Interaction Of The Cyclonic Winds With The Infrasonic Signal Generated By A Large Maritime Storm, Philip Stephen Blom

Electronic Theses and Dissertations

The collision of counter propagating ocean surface waves of like periods is known to produce an infrasonic signal termed a microbarom. It has been suggested that microbaroms associated with large maritime storms are generated far from the storm center at a location in which the storm swell and background swell have equal period and are counter-propagating. It is shown in this work that the interaction of the atmospheric microbarom signal generated by a large maritime storm with the cyclonic winds of the storm results in a characteristic acoustic signal far from the storm which could potentially be used to estimate …

Two Methodologies: How Well Can Universities Predict Retention, Tiffany Lynette Gregory

Electronic Theses and Dissertations

Student retention has been a long standing focus in higher education research with one of the earliest work dating back to 1937. Many researchers have proposed factors that affect a student's decision to depart from the university without successfully completing a degree. It is important to not only research different attributes and characteristics that affect student departure but it is also important to study different statistical methodologies. With the advancement in technology, new methodologies such as the Classification and Regression Tree (CART) have proven to yield significant results in a variety of research fields. As these new statistical methodologies emerge, …

Numerical Modeling Of Lightning Initiation And Stepped Leader Propagation, Sumedhe Karunarathne

Electronic Theses and Dissertations

Initial breakdown pulses (IBPs) observed at the beginning of cloud-to-ground (CG) lightning flashes and stepped leaders that folloIBPs were modeled using multi-sensor electric field change (E-change) measurements. This study uses data collected with a network of ten E-change sensors located at Kennedy Space Center. Locations (x,y,z,t) of IBPs were found using a time-of-arrival technique called PBFA. Location errors were determined from Monte Carlo simulations and were usually less than 100 m for horizontal coordinates and several hundreds of meters for altitude. Comparison of PBFA source locations to locations from a VHF lightning mapping system shows that PBFA locates most of …

Measurement Of Angular Coefficients Of Drell-Yan E(+) E(-) Pairs In Ppbar Collisions At Square Root Of Center Of Mass Energy Of 1.96 Tev., Sudeep Singh Bhatia

Electronic Theses and Dissertations

In this paper we present the status of the measurement of angular distributions of final state electrons in ppbar → γ*/Z → e+ e− + X events produced in the Z boson mass region at square root of center of mass energy of 1.96 TeV at the Tevatron. For this analysis, we have used the Run IIb2 dataset collected with the DΦ detector. The angular distributions as a function of the transverse momentum of the electron-positron pair are studied, and the Lam-Tung relation, valid only for a spin-1 description of the gluon is investigated. The final result will also describe …

Early Transition Metal Ccc-Nhc Pincer Complexes: Synthesis, Characterization, And Catalysis, Theodore Rudy Helgert

Electronic Theses and Dissertations

The previously reported amine elimination methodology for the metalation of CCC-NHC pincer ligand precursors has been extended to other early-transition metals and ligands. Specifically, synthetic results for the preparation of imidazole based CCC-NHC pincer Ti (IV), CCC-NHC pincer Ta (V) will be discussed. In addition, the synthesis of a new triazole based CCC-NHC pincer ligand precursor and its metalation with Ta (V) will be presented. Coordination sphere manipulation of the new pincer complexes using TMSCl for the Ti complex and lithium t-butylamide for the Ta complexes is also discussed. The reaction of the initial Ta CCC-NHC complex with lithium t-butylamide …