Physical Sciences and Mathematics Commons^™

The Urban Heat Island And Its Influence On Precipitation In Denver, Colorado, Diana Thunen

Electronic Theses and Dissertations

Anthropogenic modification of the climate is an unintended yet serious effect of urbanization and it is happening in every city across the globe in the form of the urban heat island. The purpose of this study was to see if Denver, Colorado exhibits evidence of an urban heat island using meteorological data and if there has been a change in precipitation amounts since the urbanization of the city. It was concluded that Denver, Colorado does have an urban heat island that varies seasonally throughout the year with an average magnitude of 3.57°C during the day and 3.82°C at night. The …

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 …

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).

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, …

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 …

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 …

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 …

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, …

Cost Effective Domination In Graphs, Tabitha Lynn Mccoy

Electronic Theses and Dissertations

A set S of vertices in a graph G = (V,E) is a dominating set if every vertex in V \ S is adjacent to at least one vertex in S. A vertex v in a dominating set S is said to be it cost effective if it is adjacent to at least as many vertices in V \ S as it is in S. A dominating set S is cost effective if every vertex in S is cost effective. The minimum cardinality of a cost effective dominating set of G is the cost …

Connotational Subtyping And Runtime Class Mutability In Ruby, Ian S. Dillon

Electronic Theses and Dissertations

Connotational subtyping is an approach to typing that allows an object's type to change dynamically, following changes to the object's internal state. This allows for a more precise representation of a problem domain with logical objects that have variable behavior. Two approaches to supporting connotational subtyping in the Ruby programming language were implemented: a language-level implementation using pure Ruby and a modification to the Ruby 1.8.7 interpreter. While neither implementation was wholly successful the language level implementation created complications with reflective language features like self and super and, while Ruby 1.8.7 has been obsoleted by Ruby 1.9 (YARV), the results …

A Tangle Net Study On Relative Abundance And Habitat Preference Of Elasmobranchs In North Inlet Estuary, South Carolina, Moriah Heather Moore

Electronic Theses and Dissertations

Although habitat selection is relatively well studied in some elasmobranchs, no field or lab studies have focused on sediment preference, which is important to other benthic marine vertebrates. To determine the relative abundance and sediment preference of shallow water benthic elasmobranch inhabitants of North Inlet, SC, we employed 187 30 minute tangle net sets over two sediment types (mud and sand). The majority of our capture consisted of 41 Dasyatis sayi (tagged 37) and 31 Sphyrna tiburo (tagged 14). Although D. sayi had been recorded in North Inlet, previous studies found greater numbers of congeners D. americana and D. sabina. …

Polychaete Burrowing Behavior In Sand And Mud, Kevin Terrence Du Clos

Electronic Theses and Dissertations

Marine sediments are continually reworked by resident organisms that control the ecology, chemistry, and physical structure of these vast systems. For example, the creation of a burrow brings oxygenated water into contact with anoxic sediment, facilitating aerobic respiration and supporting a distinct population of bacteria and meiofauna. Collectively, the effects of infauna on sediments and pore waters are known as bioturbation. Studying the behavior organisms that live beneath the sediment surface (infauna) is crucial to understanding the effects of bioturbation. Infauna can be difficult to study, however, because much their activity cannot be directly observed. The purpose of this thesis …

Assessing Allelopathic Effects Of Alexandrium Fundyense On Thalassiosira Sp., Emily R. Lyczkowski

Electronic Theses and Dissertations

Production of allelopathic chemicals by the toxic dinoflagellate Alexandrium fundyense is one suggested mechanism by which this relatively slow grower outcompetes other phytoplankton, particularly diatoms. Despite well documented allelopathic potential of Alexandrium spp., the potency is variable. To further characterize allelopathic effects of A. fundyense on diatoms in the Gulf of Maine, I studied growth and nutrient acquisition by the chain-forming diatom Thalassiosira sp. in the presence and absence of allelochemicals. Thalassiosira cells, upon exposure to filtrate of A. fundyense cultures exhibited “bleaching” and both growth and nutrient utilization ceased for up to 4 days compared to controls. Results from …

Ecological Interactions Affecting Diatom Climate Reconstructions In Prairie Saline Lakes Of The Northern Great Plains (Usa), Courtney R. Wigdahl

Electronic Theses and Dissertations

Sedimentary diatom profiles from saline lakes are frequently used to reconstruct lakewater salinity as an indicator of drought. However, diatom-inferred salinity reconstructions (DI-salinity) from geographically-close sites in the Great Plains (USA) have yielded disparate results. Here, I explore how within-lake ecological processes, such as physical changes in lake habitat and zooplankton grazing pressure, may affect the accuracy of diatom-based salinity reconstructions. I examined how relationships differed among drought, lake-level change, and diatom community structure over the last century by developing three-dimensional models of planktic:benthic habitat (P:B) relationships with lake level change. I explored the potential for zooplankton grazing influence by …

Lamination Of Inverted Organic Photovoltaics And Associated Physical Properties, Brian A. Bailey

Electronic Theses and Dissertations

This dissertation is the result of a series of studies involving hot press lamination of inverted organic photovoltaics. It first gives background and develops a lamination process for fabrication. Then, the process is used to answer fundamental questions about organic photovoltaics and to fabricate previously impossible or overly complicated devices. Finally, the author examines the scientific theory which describes the process and aligns that theory with related measurements.

The field of organic photovoltaics is introduced and the lamination process is developed and optimized. In the lamination process, part of the solar cell is deposited onto a rigid substrate, and the …

Episodic Recruitment And Climate Analysis Of Ponderosa Pine On The Palmer Divide, Eastern Colorado, William Henry Brenton Jr.

Electronic Theses and Dissertations

Previous recruitment studies on populations of ponderosa pine (Pinus ponderosa P. & C. Lawson) in Colorado have been limited to the western mountains and the Front Range. In this research I used tree-ring data to reconstruct recruitment for ponderosa pine near the eastern limits of its distribution at two sites on the Palmer Divide, Eastern Colorado, to determine the relative climate sensitivity of the two sites, and the extent to which climate or other factors may have influenced recruitment at the sites. The results of the tree-ring analysis suggest that ponderosa pines in more the easterly site lower elevation …

Integer Solutions To Optimization Problems And Modular Sequences Of Nexus Numbers, Jeremy T. Davis

Electronic Theses and Dissertations

In this thesis, we examine the use of integers through two ideas. As mathematics teachers, we prefer students not use calculators on assessments. In order to require this, students compute the problems by hand. We take a look at the classic Calculus I optimization box problem while restricting values to integers. In addition, sticking with the integer theme, we take a new look at the nexus numbers. Nexus numbers are extensions of the hex and rhombic dodecahedral numbers. We put these numbers into a sequence, and through a few computations of modular arithmetic, we analyze the sequences and their patterns …

Finding A Better Confidence Interval For A Single Regression Changepoint Using Different Bootstrap Confidence Interval Procedures, Bodhipaksha Thilakarathne

Electronic Theses and Dissertations

Recently a number of papers have been published in the area of regression changepoints but there is not much literature concerning confidence intervals for regression changepoints. The purpose of this paper is to find a better bootstrap confidence interval for a single regression changepoint. ("Better" confidence interval means having a minimum length and coverage probability which is close to a chosen significance level). Several methods will be used to find bootstrap confidence intervals. Among those methods a better confidence interval will be presented.

Integer Compositions, Gray Code, And The Fibonacci Sequence, Linus Lindroos

Electronic Theses and Dissertations

In this thesis I show the relation of binary and Gray Code to integer compositions and the Fibonacci sequence through the use of analytic combinatorics, Zeckendorf's Theorem, and generating functions.

Compositions, Bijections, And Enumerations, Charles R. Dedrickson Iii

Electronic Theses and Dissertations

In this thesis we give an introduction to colored-compositions of an integer. This is a generalization of traditional integer compositions, and we show a few results for n-color compositions which are analogous to regular compositions with both combinatorial and analytic proofs. We also show several bijections between various types of compositions to certain types of numeric strings, and provide a generalization of a classic bijection between compositions and binary strings.

A Non-Parametric Approach To Change-Point Detection In Cross-Asset Correlations, L. Kaili Diamond

Electronic Theses and Dissertations

In this thesis we explore the problem of detecting change-points in cross-asset correlations using a non-parametric approach. We began by comparing and contrasting several common methods for change-point detection as well as methods for measuring correlation. We finally settle on a statistic introduced in early 2012 by Herold Dehling et.al. and test this statistic against real world financial data. We provide the estimated change-point for this data as well as the asymptotic p-value associated with this statistic. Once this process was complete we went on to use simulated data to measure the accuracy, power, and type 1 error associated with …

Landmark Analysis Of Musteloid Carnassials Applied To Taxonomic Identification And Examination Of Sexual Dimorphism And Regional Morphotypes, Joel Alvin Christine

Electronic Theses and Dissertations

Guy Wilson Cave (GWC) in Sullivan County, Tennessee holds many late Pleistocene mammal fossils. Based on visual morphology, several partial mandibles with lower carnassial from GWC appeared to be musteloids. Geometric morphometrics has been successfully used to identify fragmentary fossils, so a landmark based, 2 dimensional technique was applied to identify the GWC musteloids using the lower carnassial. Digital images of several GWC fossils and of extant reference musteloids were combined using morphometric programs tpsDIG1, tpsUtil, and tpsSuper. Statistical data analysis was performed in PASW Statistics. Results successfully separated Mephitis mephitis (striped skunk) from M. macroura (hooded skunk) and Martes …

Nested (2,R)-Regular Graphs And Their Network Properties., Josh Daniel Brooks

Electronic Theses and Dissertations

A graph G is a (t, r)-regular graph if every collection of t independent vertices is collectively adjacent to exactly r vertices. If a graph G is (2, r)-regular where p, s, and m are positive integers, and m ≥ 2, then when n is sufficiently large, then G is isomorphic to G = K_s+mK_p, where 2(p-1)+s = r. A nested (2,r)-regular graph is constructed by replacing selected cliques with a (2,r)-regular graph and joining the vertices of the peripheral cliques. For …

Cursorial Adaptations In The Forelimb Of The Giant Short-Faced Bear, Arctodus Simus, Revealed By Traditional And 3d Landmark Morphometrics, Eric Randally Lynch

Electronic Theses and Dissertations

The paleobiology of the Pleistocene North American giant short-faced bear, Arctodus simus, has eluded paleontologists for decades. Its more gracile form has led past researchers to myriad intepretations of the locomotion and feeding ecology of this species. While earlier studies have focused on craniodental morphology and simple postcranial indices, it is forelimb morphology that represents a direct compromise between locomotor and foraging behavior. The study here uses traditional and 3D landmark morphometrics to more completely compare the 3-dimensional shape of the major forelimb elements and their muscle attachment sites between A. simus, extant ursids, and other carnivorans. Results …

Immobilized Bis-Indenyl Ligands For Stable And Cost-Effective Metallocene Catalysts Of Hydrogenation And Polymerization Reactions, Thomas Max Simerly

Electronic Theses and Dissertations

Reactions of catalytic hydrogenations and polymerizations are widely used in industry for manufacture of fine chemicals, pharmaceuticals, and plastics. Homogeneous catalysts for the processes that have low stability and their separation is difficult. Therefore, the development of new highly active and stable catalysts for hydrogenations and polymerizations is a necessity. The objective of this research was the development of a strategy for immobilization of heterogeneous metallocene catalysts. First, a methodology of immobilization of bis-indenyl ligands on the surface of mesoporous silica gel was designed. Four bis-indenyl ligands containing functionalized tethers of various lengths with terminal alkene groups were synthesized. All …

Global Domination Stable Graphs, Elizabeth Marie Harris

Electronic Theses and Dissertations

A set of vertices S in a graph G is a global dominating set (GDS) of G if S is a dominating set for both G and its complement G. The minimum cardinality of a global dominating set of G is the global domination number of G. We explore the effects of graph modifications on the global domination number. In particular, we explore edge removal, edge addition, and vertex removal.

An Auv Simulator For Incorporating Physical Feedback, James Brawn Jr.

Electronic Theses and Dissertations

Traditional physics simulators use mathematical models to represent a realistic environment. Natural processes, however, are difficult to mimic accurately. We present a simulator that has the capability to alter its model based on actual physical measurements.

The simulator runs as a server to which remote clients can connect and assume control of entities within the virtual environment. The simulator then sends position updates to clients according to its model. Clients have the option of then correcting the data in these updates, sending feedback to the server. The server adjusts its model to accord with the corrections, allowing for a more …

Circulation And Transport In Casco Bay, Maine, Gregory H. Sinnett

Electronic Theses and Dissertations

General circulation and transport exchange within Casco Bay, Maine occurs primarily through the three deepest channels separating the interior sections of the Bay from the outer Bay and adjacent Western Gulf of Maine shelf. Resource management in Casco Bay relies on an ability to predict and/or track oil spill trajectories, Red Tide events, nutrient plumes, pollution and other factors important to the estuarine environment. However, the exchange through these channels, the mean circulation and associated forcing mechanisms are not well understood. In this study, time series of current velocities, temperature, salinity and wind data collected during 2004 and 2005 are …

Design And Synthesis Of Novel Fluorescent Nucleoside Analogues, Nada Abdulnasir Elsharif

Electronic Theses and Dissertations

This project aimed to obtain a set of fluorescent nucleoside analogues that closely resemble cytosine with extending the aromatic surface (extended conjugation) for enhance the photophysical properties. In addition to synthesize new fluorescent nucleoside analogues and evaluate their photophysical properties, this project aimed to understand the effects of donor substituent on the tC photophysical properties.

The main goal of these studies is to develop highly fluorescent nucleotide analogues. We first were looking to synthesize tC^C fluorescent nucleotide with the pyrimido[4,5-b]quinolone. In this part, 2-chloro-3- formylquinoline was easily prepared, yet the cyclization of 2-chloro-3- formylquinoline with urea or guanidine HCl …

Liar's Domination In Grid Graphs, Christopher Kent Sterling

Electronic Theses and Dissertations

As introduced by Slater in 2008, liar's domination provides a way of modeling protection devices where one may be faulty. Assume each vertex of a graph G is the possible location for an intruder such as a thief. A protection device at a vertex v is assumed to be able to detect the intruder at any vertex in its closed neighborhood N[v] and identify at which vertex in N[v] the intruder is located. A dominating set is required to identify any intruder's location in the graph G, and if any one device can fail to …