Physical Sciences and Mathematics Commons^™

Micro-Environment And Plant Assemblage Structure On Virginia's Barrier Island "Pimple" Dunes, Brett A. Mcmillan, Frank P. Day

Biological Sciences Faculty Publications

“Pimple” dunes are small, rounded coastal dunes that form along major dune ridges of the barrier islands along the Eastern Shore of Virginia. Although most pimple dunes are small structures ranging between 10 and 20 m in diameter, they have distinct plant assemblages that replicate the upland ecotones of their barrier islands. We examined the relationship between microenvironment, edaphic factors, and plant assemblage structure on pimple dunes. Water availability was an obvious major ecological driver, but we also tested other environmental factors that may correlate with plant assemblage structure. We found distinct assemblage types that segregated themselves by habitat type: …

Precision Measurement Of The Hydrogen-Deuterium 1s-2s Isotope Shift, Christian G. Parthey, Arthur Matveev, Janis Alnis, Randolf Pohl, Thomas Udem, Ulrich D. Jentschura, Nikolai Kolachevsky, Theodor W. Hänsch

Physics Faculty Research & Creative Works

Measuring the hydrogen-deuterium isotope shift via two-photon spectroscopy of the 1S-2S transition, we obtain 670994334606(15) Hz. This is a 10-times improvement over the previous best measurement confirming its frequency value. a calculation of the difference of the mean square charge radii of deuterium and hydrogen results in r2d-r2 p=3.82007(65)fm2, a more than twofold improvement compared to the former value.

Pharmaceutical Compounds In Treatment Wetlands: Potential Removal And Effects On Microbial Processes, Jeremy Landon Conkle

LSU Doctoral Dissertations

active compounds (PhACs) have been detected in the aquatic environment as a result of loading from various sources. In Louisiana, USA, many municipalities treat wastewater using natural systems, such as lagoons and wetlands, rather than using conventional wastewater treatment technologies and may discharge PhACs into the environment. These treatment systems are not designed to remove PhACs from wastewater, nor is it currently a regulatory requirement. Research on the fate of PhACs in the environment is needed to understand impacts on Louisiana’s important coastal system. Wastewater sampling for PhACs at the Mandeville, LA wastewater treatment plant (WWTP) determined that this system …

Analysis And Modeling Of Hurricane Impacts On A Coastal Louisiana Lake Bottom, Angelina Freeman

LSU Doctoral Dissertations

Tropical cyclone impacts on wetland, terrestrial, and shelf systems have been previously studied and reasonably delineated, but little is known about the response of coastal lakes to storm events. For the first time, tropical cyclone impacts on a shallow coastal lake in the Louisiana coastal plain have been studied using direct lines of evidence and numerical modeling. Using side-scan sonar, CHIRP subbottom and echo sounder bathymetric profiles, the lake bottom and shallow subsurface of Sister Lake was imaged pre- and post-Hurricanes Katrina and Rita to provide a geologic framework for assessing the effects of these storms. Box cores were collected …

Four-Body Charge Transfer Processes In Heavy Particle Collisions, Allison L. Harris, Jerry Peacher, Michael Schulz, Don H. Madison

Physics Faculty Research & Creative Works

Fully differential cross sections (FDCS) for proton + helium single capture and transfer-excitation collisions are presented using the Four-Body Transfer-Excitation (4BTE) model. This is a first order perturbative model that allows for any two-particle interaction to be studied. For single capture, the effect of the projectile-nuclear term in the perturbation is examined. It is shown that inclusion of this term results in an unphysical minimum in the FDCS, but is required to correctly predict the magnitude of the experimental results. For transfer-excitation, the role of electron correlation in the target helium atom is studied, and shown to be unimportant in …

The Bronx River Alliance: A Model Community Action Organization And An Internship In Development, John Hinck

Student Theses 2001-2013

-

Ab Initio Calculations And Ellipsometry Measurements Of The Optical Properties Of The Layered Semiconductor In4Se3, L. Makinistian, E. A. Albanesi, N. V. Gonzalez Lemus, A. G. Petukhov, D. Schmidt, Eva Schubert, M. Schubert, Yaroslav B. Losovyj, P. Galiy, Peter A. Dowben

Peter Dowben Publications

In this work, we present a thorough study of the optical properties of the layered orthorhombic compound In₄Se₃. The dielectric function—real and imaginary parts, the complex refraction index, the reflectivity, the absorption coefficient, and the conductivity of In₄Se₃ were calculated with the inclusion of the spin-orbit interaction, using an ab initio FP-LAPW method based on DFT. Also, generalized ellipsometry was employed for more precise measurement of the anisotropic dielectric functions for polarization along crystal a, b, and c axes of orthorhombic absorbing In₄Se₃ single crystals cut approximately parallel to …

The Electron–Phonon Coupling At The Mo(112) Surface, Ning Wu, Keisuke Fukutani, Peter A. Dowben

Peter Dowben Publications

We investigated the electron–phonon coupling (EPC), in the vicinity of the Fermi level, for the surface-weighted states of Mo(112) from high resolution angle-resolved photoemission data taken parallel to the surface corrugation (i.e. (111)). The surface-weighted bandwidth may be discussed in terms of electron–electron interactions, electron impurity scattering and electron–phonon coupling and exhibits a mass enhancement factor λ = 0.42, within the Debye model, determined from the experimentally derived self-energy. Gold overlayers suppress the mass enhancement of the Mo(112) surface-weighted band crossing the Fermi level at 0.54 Å^-1.

The Local Structure Of Transition Metal Doped Semiconducting Boron Carbides, Jing Liu, Guangfu Luo, Wai-Ning Mei, Orhan Kizilkaya, Eric D. Shepherd, Jennifer I. Brand, Peter A. Dowben

Peter Dowben Publications

Transition metal doped boron carbides produced by plasma enhanced chemical vapour deposition of orthocarborane (closo-1,2-C₂B₁₀H₁₂) and 3d metal metallocenes were investigated by performing K-edge extended x-ray absorption fine structure and x-ray absorption near edge structure measurements. The 3d transition metal atom occupies one of the icosahedral boron or carbon atomic sites within the icosahedral cage. Good agreement was obtained between experiment and models for Mn, Fe and Co doping, based on the model structures of two adjoined vertex sharing carborane cages, each containing a transition metal. The local spin configurations of all …

Semiclassical Complex-Time Method For Tunneling Ionization: Molecular Suppression And Orientational Dependence, Gordon A. Gallup, Ilya I. Fabrikant

Gordon Gallup Publications

We apply a previously developed semiclassical complex time method to the calculation of tunneling ionization of several diatomic molecules and CO₂.We investigate the presence or absence of the molecular suppression effect by calculating ionization rates of N₂ versus Ar, O₂ versus Xe, F₂ versus Ar, and CO versus Kr. Comparisons with other theories, including the molecular-orbital-Ammosov-Delone-Krainov (MO-ADK) model and the strong-field approximation, are given. We also analyze the dependence of the ionization rate on the angle θ_F between the molecular axis and the field direction. The theoretical results agree quite well with experiment for …

Coupled Neutron Transport For Hzetrn, T.C. Slaba, S.R. Blattnig, S.K. Aghara, L.W. Townsend, T. Handler, T.A. Gabriel, L.S. Pinsky, B. Reddell

United States National Aeronautics and Space Administration: Publications

Exposure estimates inside space vehicles, surface habitats, and high altitude aircrafts exposed to space radiation are highly influenced by secondary neutron production. The deterministic transport code HZETRN has been identified as a reliable and efficient tool for such studies, but improvements to the underlying transport models and numerical methods are still necessary. In this paper, the forward– backward (FB) and directionally coupled forward–backward (DC) neutron transport models are derived, numerical methods for the FB model are reviewed, and a computationally efficient numerical solution is presented for the DC model. Both models are compared to the Monte Carlo codes HETC-HEDS, FLUKA, …

High-Order Finite Difference Methods With Subcell Resolution For Hyperbolic Conservation Laws With Stiff Reaction Terms: Preliminary Results, W. Wang, C.-W. Shu, Helen Yee, Bjorn Sjögreen

United States National Aeronautics and Space Administration: Publications

The motivation for this research stems from the high-speed chemical reacting flows which have stiff reaction terms, where the chemical time scales are often much smaller than the fluid dynamics time scales. It is usually too expensive to resolve all the spatial/ temporal scales if we are only interested in the main flow. On the other hand, insufficient spatial/temporal resolution will cause the speed of propagation of discontinuities to be incorrectly predicted for many numerical methods. This numerical phenomenon was first observed by Colella et al. (1986). Then LeVeque & Yee (1990) showed that a similar spurious propagation phenomenon can …

High-Order Simulation Of Hypersonic Nonequilibrium Flows On Overset Grids, A. Lani, Bjorn Sjögreen, Helen Yee

United States National Aeronautics and Space Administration: Publications

The time-accurate unsteady 3D compressible flow solver ADPDIS3D is supported by a grant from the Department of Energy (DOE) SciDAC program through the Science Application Partnership (SAP) initiative. The objective of this grant is to develop, implement and validate this variable high-order 3-D multiblock overlapping (overset) grid solver for turbulence with strong shocks and density variations. ADPDIS3D includes capabilities for both direct numerical simulation (DNS), resolving all scales of the flow fields, and large eddy simulation (LES) modeling the small turbulent scales. One of the unique features of the code is the ability to perform DNS and LES computations in …

Basic Social Math: A Linguistic Upgrade For Decision Analysis And Social Dynamics Research., Jared Hanson

MA TESOL Collection

There are foundational errors in the mathematical frameworks currently used in Economic and Decision Theories. Recent systemic failures in the interdependent business and educational sectors also show that many practices based on these theories are unsustainable in the changing dynamics of the global economy. A new approach is needed in social science research and systems engineering. This paper examines how the new understandings of complex systems, the role of emotion in cognition, and the core dynamics of decision making can help us correct these errors and to create a general framework for systemic innovation. It argues for the development of …

The College Of Extended Learning Online Registration System, Ching-Yi Wang

Theses Digitization Project

The purpose of this study was to build an online method to register for classes for the College of Extended Learning Online Registration System (CELORS). This system was initially built so that the College of Extended Learning could offer its students an online method to register for classes, in addition to the traditional methods of registering by phone, by fax, by mail, or in person. Over the last few years, the system has been routinely modified to meet the needs of the College to suit their ever-changing business rules.

Bacteria Monitoring And Assessment Project At Canyon Lake, California, Natasha Marie Krupnak

Theses Digitization Project

This study was conducted in response to a cooperative request by the Lake Elsinore and Canyon Lake Total Maximum Daily Load Task Force and the Santa Ana Regional Water Quality Control Board to characterize and assess the bacterial water quality conditons in Canyon Lake, California which is a fresh water recreational lake.

Estimated Area Of Impervious Parking Surfaces And The Potential Groundwater Recharge Increase Through Permeable Pavement Retrofit In The Chino Basin, Zablon Afera Adane

Theses Digitization Project

California recently declared a state of emergency over drought followiing three years of below average rain and snowfall. There is a consensus among many involved in water supply in California for finding new sources of water, conservation, and increasing recharge to replenish the groundwater with surface water that would have been lost to run off. This study investigates the amount of stormwater that could potentially be reinvested as groundwater recharge by simply transforming selected impermeable parking lots of the commercial, industrial, and institutional sectors into pervious pavement that allow water to infiltrate rather than be lost as urban runoff.

Homomorphic Images Of Progenitors Of Order Three, Mark Gutierrez

Theses Digitization Project

The main purpose of this thesis is to construct finite groups as homomorphic images of infinite semi-direct products, 2*n : N, 3*n : N, and 3*n :m N, where 2*n and 3*n are free products of n copies of the cyclic group C₂ extended by N, a group of permutations on n letters.

Online Administration System For Small And Medium-Sized Running Events, Steinar Johansen

Theses Digitization Project

The purpose of this project is to address inefficiency at small to medium-sized running events with regards to registration, race timing, and result service. As a race coordinator or participant, it is important that the race timing is correct and that the result service can be delivered as soon as possible after the event in finished. Contains source code.

The Riesz Representation Theorem For Linear Functionals, Thomas Daniel Schellhous

Theses Digitization Project

This study will investigate the Riesz representation theorem for linear functionals in relation to locally compact Hausdorff spaces. Two other theorems that are commonly called "Riesz representation theorem" are the theorem for finite-dimensional inner product spaces and the theorem for Hilbert spaces [BN00], and studying these interesting topics helps us to not only gain a better understanding of how linear functionals interact with vector spaces over which they are defined, but also to see faint threads that hint at a deep connection between the various fields of modern mathematics.

Conversion Of Racemic Ibuprofen To (S)-Ibuprofen, David Chavez-Flores

Open Access Theses & Dissertations

Ibuprofen is a common Non-Steroidal Anti-Inflammatory Drug (NSAID) sold as a racemic or equal mixture of (R) and (S) mirror-image enantiomers. Without patent protection, ibuprofen is an orphan drug even though one enantiomer, (S)-ibuprofen, provides relief three times faster than its racemic mixture with fewer side effects. The goal of this research was to develop a facile, environmentally benign (no waste of ibuprofen or catalysts), and inexpensive process to convert a commercially available racemic mixture of ibuprofen to the therapeutically active (S)-ibuprofen.

After many attempts, the most successful conversion of racemic ibuprofen to (S)-ibuprofen was the in situ racemization and …

Characterization Of Mantle/Crust Interactions Using Pb Isotope Analyses Of Lavas In The Southern Rio Grande Rift, New Mexico, Lynnette Crocker

Open Access Theses & Dissertations

The Pb isotope composition of volcanic rocks in the Rio Grande Rift (RGR) can be used to investigate the interaction of mantle melts with continental lithosphere, and has important implications for the composition of the lithosphere. We suggest some compositional signatures may pre-date current tectonic processes. Existing data from several volcanic fields in New Mexico show a converging pattern on a very limited Pb isotope range, corresponding to lower crustal xenolith compositions from Kilbourne Hole. The different volcanic fields show Pb isotope trends diverging from this lower crustal composition, likely depicting mixing with different upper crustal reservoirs. These very common, …

Gaze, Turn-Taking And Proxemics In Multiparty Versus Dyadic Conversation Across Cultures, David Alberto Herrera

Open Access Theses & Dissertations

When people converse with others, they participate in joint interaction behaviors, like proxemics or interpersonal distance, mutual gaze, and turn-taking or pause and overlap, which they may not consciously negotiate. How these behaviors manifest depends on many factors, such as gender, age, personality, culture, and number of participating conversants. Understanding these differences is important for situations where intercultural joint interaction behaviors are necessary for mission success, such as for military personnel in foreign countries. They may also be useful for modeling embodied conversational agents where culture and group vary. Joint interaction behaviors have been extensively studied for American dyads, and …

Reduced Electronic Spaces For Modeling Donor/Acceptor Interactions, Robert J. Cave, Stephen T. Edwards '06, John A, Kouzelos '07, Marshall D. Newton

All HMC Faculty Publications and Research

Diabatic states for donor (D) and acceptor (A) interactions in electron transfer (ET) processes are formulated and evaluated, along with coupling elements (H_DA) and effective D/A separation distances (r_DA), for reduced electronic spaces of variable size, using the generalized Mulliken Hush model (GMH), applicable to an arbitrary state space and nuclear configuration, and encompassing Robin−Day class III and as well as class II situations. Once the electronic state space is selected (a set of n ≥ 2 adiabatic states approximated by an orbital space based on an effective 1-electron (1-e) Hamiltonian), the charge-localized GMH …

Jane: A New Tool For The Cophylogeny Reconstruction Problem, Chris Conow, Daniel Fielder '11, Yaniv J. Ovadia '10, Ran Libeskind-Hadas

All HMC Faculty Publications and Research

Background

This paper describes the theory and implementation of a new software tool, called Jane, for the study of historical associations. This problem arises in parasitology (associations of hosts and parasites), molecular systematics (associations of orderings and genes), and biogeography (associations of regions and orderings). The underlying problem is that of reconciling pairs of trees subject to biologically plausible events and costs associated with these events. Existing software tools for this problem have strengths and limitations, and the new Jane tool described here provides functionality that complements existing tools.

Results

The Jane software tool uses a polynomial time dynamic …

A Novel Binarization Algorithm For Ballistics Imaging Systems, Zhihu Huang, Jinsong Leng

Research outputs pre 2011

The identification of ballistics specimens from imaging systems is of paramount importance in criminal investigation. Binarization plays a key role in preprocess of recognizing cartridges in the ballistic imaging systems. Unfortunately, it is very difficult to get the satisfactory binary image using existing binary algorithms. In this paper, we utilize the global and local thresholds to enhance the image binarization. Importantly, we present a novel criterion for effectively detecting edges in the images. Comprehensive experiments have been conducted over sample ballistic images. The empirical results demonstrate the proposed method can provide a better solution than existing binary algorithms.

Voting In Agreeable Societies, Deborah E. Berg '06, Serguei Norine, Francis E. Su, Robin Thomas, Paul Wollan

All HMC Faculty Publications and Research

No abstract provided in this article.

Two-Player Envy-Free Multi-Cake Division, John Cloutier '03, Kathryn L. Nyman, Francis E. Su

All HMC Faculty Publications and Research

We introduce a generalized cake-cutting problem in which we seek to divide multiple cakes so that two players may get their most-preferred piece selections: a choice of one piece from each cake, allowing for the possibility of linked preferences over the cakes. For two players, we show that disjoint envy-free piece selections may not exist for two cakes cut into two pieces each, and they may not exist for three cakes cut into three pieces each. However, there do exist such divisions for two cakes cut into three pieces each, and for three cakes cut into four pieces each. The …

Anisotropy Of Domain Growth In Epitaxial Ferroelectric Capacitors, D. Wu, I. Vrejoiu, M. Alexe, Alexei Gruverman

Alexei Gruverman Publications

Piezoresponse force microscopy (PFM) has been applied to investigate the switching kinetics in microscale epitaxial Pb(Zr,Ti)O₃ capacitors. It is shown that transition from low to high field range brings about a qualitative change in domain growth kinetics, namely, laterally isotropic growth in the high fields as opposed to highly anisotropic growth in the low fields. It is suggested that anisotropy of domain growth can be attributed to orientational variations in the activation energy due to film microstructure. Fitting the switching kinetics using the Kolmogorov–Avrami–Ishibashi model shows excellent agreement with the PFM experimental data and yields the integer values of …

A Low-Voltage Retarding-Field Mott Polarimeter For Photocathode Characterization, J.L. Mccarter, M.L. Stutzman, K.W. Trantham, Timothy G. Anderson, A.M. Cook, Timothy J. Gay

Timothy J. Gay Publications

Nuclear physics experiments at Thomas Jefferson National Accelerator Facility’s CEBAF rely on high polarization electron beams. We describe a recently commissioned system for prequalifying and studying photocathodes for CEBAF with a load-locked, low-voltage polarized electron source coupled to a compact retarding-field Mott polarimeter. The polarimeter uses simplified electrode structures and operates from 5 to 30 kV. The effective Sherman function for this device has been calibrated by comparison with the CEBAF 5 MeV Mott polarimeter. For elastic scattering from a thick gold target at 20 keV, the effective Sherman function is 0.201(5). Its maximum efficiency at 20 keV, defined as …