Physical Sciences and Mathematics Commons^™

Magnetic And Electronic Properties Of Thin (Ga,Mn)N Films Due To An Embedded Mn-Delta-Doping Layer, H. C. Jeon, S. J. Lee, Tae Won Kang, K. J. Chang, Yung Kee Yeo, T. F. George

Faculty Publications

The magnetization curve as a function of the magnetic field at 5 K showed that the magnetization in the (Ga_0.995Mn_0.005)N thin film was significantly enhanced due to Mn delta-doping. The magnetization curve as a function of the temperature showed that the Curie temperature of the Mn delta-doped (Ga_0.995Mn_0.005)N thin film was estimated to be above room temperature. The theoretical results showed that Ga vacancies near the Mn delta-doping layer were likely to cause p-type conductance in the (Ga_0.995Mn_0.005)N thin film. Abstract © 2011 AIP

U.S. Extended Continental Shelf Cruise To Map Sections Of The Mariana Trench And The Eastern And Southern Insular Margins Of Guam And The Northern Mariana Islands, Andy Armstrong

Center for Coastal and Ocean Mapping

U.S. Extended Continental Shelf Cruise to Map Sections of the Mariana Trench and the Eastern and Southern Insular Margins of Guam and the Northern Mariana Islands

CCOM-JHC CRUISE SU10-02

Leg 2: September 24 to October 21, 2010

Apra Harbor, Guam to Apra Harbor, Guam

Are Three Flavors Special?, Joseph Schechter, Amir H. Fariborz, Renata Jora, M. Naeem Shahid

Physics - All Scholarship

It has become clearer recently that the regular pattern of three flavor nonets describing the low spin meson multiplets seems to require some modification for the case of the spin 0 scalar mesons. One picture which has had some success, treats the scalars in a chiral Lagrangian framework and considers them to populate two nonets. These are, in turn, taken to result from the mixing of two "bare" nonets, one of which is of quark- antiquark type and the other of two quark- two antiquark type. Here we show that such a mixing is, before chiral symmetry breaking terms are …

Investigation Of Select Ruthenium Compounds As Hds Catalyst Models, Leslie Wayne Foster

Student Theses and Dissertations

The hydordesulfurization (HDS) process is an industrial process that removes sulfur impurities from fossil fuel feedstocks prior to refining. This process includes the use of very high temperatures and pressures of H2 in combination with a sulfided transition metal catalyst. While the exact mechanism for the HDS process is unknown, there are continual strides in improving the process. Limitations in the current HDS models include non-sulfur ligands in the coordination sphere of the central metal. Attempted reactions of cis-[Ru(dmso)4Cl2] with tri-thiocarbonate gave the unexpected fac-[Ru(dmso)3Cl2(OH2)] compound. Successful thiol coordination to CpRu(PPh3)2+ has been demonstrated in the literature. Reactions of [ç6-C6H6RuCl2]2 …

Efficacy Of A Novel Chelator For Mercury Chelation And Distribution, David Harold Clarke

Student Theses and Dissertations

Mercury is found throughout the environment with a distribution on a global scale in nearly all terrestrial to marine environments. Biotransformation of divalent mercury and subsequent bioaccumulation of organo-mercury species is catalyzed by sulfate reducing bacteria. Trophic transport of the resultant methyl mercury, a highly toxic species, leads to upward accumulation in the trophic structure of aquatic environments and ultimately to human exposure through consumption of methyl mercury laden fish. The potential for human health risk has made mercury a high priority environmental contaminant. Research aimed at assessing the within-organism fate of mercury using a genetically tractable mammalian model is …

Ensemble Forecast Spread Induced By Soil Moisture Changes Over Mid-South And Neighbouring Midwestern Region Of The Usa, Arturo I. Quintanar, Rezaul Mahmood

School of Natural Resources: Faculty Publications

This study investigated the potential impact of soil moisture perturbations on the statistical spread of an ensemble forecast for three different synoptic events during the summer of 2006. Soil moisture was perturbed from a control simulation to generate a 12 member ensemble with six drier and six moister soils. The impacts on the near-surface atmospheric conditions and on precipitation were analysed. It was found, as previous studies have confirmed, that soil moisture can change the spatial and temporal distribution of precipitation and of the overlying circulation. It was found that regardless of the conditions in synoptic forcing, temperature, relative humidity …

Kinetics Of The Electrical Discharge Pumped Oxygen-Iodine Laser, Matthew A. Lange

Theses and Dissertations

A systematic study of microwave discharges at 2.45 GHz has been performed through the pressure range of sustainable electric discharges in pure oxygen flows of 2 to 10 Torr. A corresponding study of 13.56 MHz has also been performed at pressures of 2, 4, and 7 Torr. Optical emissions from O2(a 1Δ), O2(b 1Σ), and O-atoms have been measured from the center of a μ-wave discharge. Discharge residence times from 0.1 to 5 ms have been reported. The O2(b 1Σ) emissions, with a spectral resolution of 0.01 nm, have been used to measure the temperature of the gas, which typically …

Electroluminescence Studies On Longwavelength Indium Arsenide Quantum Dot Microcavities Grown On Gallium Arsenide, John C. Ramsey

Theses and Dissertations

A comprehensive study of the electroluminescence of four GaAs/AlGaAs microcavity devices with InAs/GaInAs quantum dot active regions emitting near 1.3 µm was conducted. The four molecular beam epitaxial grown samples with AlAs oxide aperture confinement layers were fabricated, characterized, and optically modeled. Optical power transmission of the samples was modeled using Matlab and compared with measured transmission data. Resonant cavity light emitting diodes (RCLEDs) and three vertical cavity surface emitting laser (VCSEL) samples were fabricated and electro-optically characterized over a range of injection currents and temperatures. Devices achieved continuous wave room temperature lasing at 1.28 µm with an output power …

Interstaple Dithiol Cross-Linking In Au 25(Sr) 18 Nanomolecules: A Combined Mass Spectrometric And Computational Study, Vijay Reddy Jupally, Rajesh Kota, Eric Van Dornshuld, Daniell L. Mattern, Gregory S. Tschumper, De En Jiang, Amala Dass

Chemistry Faculty Research & Creative Works

A systematic study of cross-linking chemistry of the Au 25(SR) 18 nanomolecule by dithiols of varying chain length, HS-(CH₂)_n-SH where n = 2, 3, 4, 5, and 6, is presented here. Monothiolated Au₂₅ has six [RSAuSRAuSR] staple motifs on its surface, and MALDI mass spectrometry data of the ligand exchanged clusters show that propane (C3) and butane (C4) dithiols have ideal chain lengths for interstaple cross-linking and that up to six C3 or C4 dithiols can be facilely exchanged onto the cluster surface. Propanedithiol predominately exchanges with two monothiols at a time, making cross-linking bridges, …

Multi- Autonomous Vehicle Insertion-Extraction System (Mavies), Jamie C. Macbeth, Manal Habib, Armen Mkrtchyan, Missy Cummings

Computer Science: Faculty Publications

MAVIES (Multi-Autonomous Vehicle Insertion-Extraction System) is the culmination of a year-long multi-stakeholder e ort between UTRC and the Humans and Automation Lab at MIT to design a human inter- face for insertion and extraction missions with multiple UAVs and option- ally piloted rotorcraft. The design process is a successful application of the Hybrid Cognitive Task Analysis (hCTA) process that tracks dozens of tasks, decision-making processes and their associated situation aware- ness requirements to determine the proper allocation of responsibilities between the human operator and the automated mission planner.

This paper discusses the various accomplishments through several phases of a disciplined …

Formation Of Organized Nanostructures From Unstable Bilayers Of Thin Metallic Liquids, Mikhail Khenner, Sagar Yadavali, Ramki Kalyanaraman

Mathematics Faculty Publications

Dewetting of pulsed-laser irradiated, thin (< 20 nm), optically reflective metallic bilayers on an optically transparent substrate with a reflective support layer is studied within the lubrication equations model. A steady-state bilayer film thickness (h) dependent temperature profile is derived based on the mean substrate temperature estimated from the elaborate thermal model of transient heating and melting/freezing. Large thermocapillary forces are observed along the plane of the liquid-liquid and liquid-gas interfaces due to this h-dependent temperature, which, in turn, is strongly influenced by the h-dependent laser light reflection and absorption. Consequently the dewetting is a result of the competition between thermocapillary and intermolecular forces. A linear analysis of the dewetting length scales established that the non-isothermal calculations better predict the experimental results as compared to the isothermal case within the bounding Hamaker coefficients. Subsequently, a computational non-linear dynamics study of the dewetting pathway was performed for Ag/Co and Co/Ag bilayer systems to predict the morphology evolution. We found that the systems evolve towards formation of different morphologies, including core-shell, embedded, or stacked nanostructure morphologies.

A Search For The Transit Of Hd 168443b: Improved Orbital Parameters And Photometry, G. Pilyavsky, S. Mahadevan, S. R. Kane, A. W. Howard, D. R. Ciardi, C. De Pree, D. Dragomir, D. A. Fischer, G. W. Henry, Eric L.N. Jensen, G. Laughlin, H. Marlowe, M. Rabus, K. Von Braun, J. T. Wright, X. X. Wang

Physics & Astronomy Faculty Works

The discovery of transiting planets around bright stars holds the potential to greatly enhance our understanding of planetary atmospheres. In this work we present the search for transits of HD 168443b, a massive planet orbiting the bright star HD 168443 (V = 6.92) with a period of 58.11 days. The high eccentricity of the planetary orbit (e = 0.53) significantly enhances the a priori transit probability beyond that expected for a circular orbit, making HD168443 a candidate for our ongoing Transit Ephemeris Refinement and Monitoring Survey. Using additional radial velocities from Keck High Resolution Echelle Spectrometer, we refined the orbital …

Hyperspectral Data Processing In A High Performance Computing Environment: A Parallel Best Band Selection Algorithm, Stefan Robila, Gerald Busardo

Department of Computer Science Faculty Scholarship and Creative Works

Hyperspectral data are characterized by a richness of information unique among various visual representations of a scene by representing the information in a collection of grayscale images with each image corresponding to a narrow interval in the electromagnetic spectrum. Such detail allows for precise identification of materials in the scene and promises to support advances in imaging beyond the visible range. However, hyperspectral data are considerably large and cumbersome to process and efficient computing solutions based on high performance computing are needed. In this paper we first provide an overview of hyperspectral data and the current state of the art …

Optical Polarization And Spectral Variability In The M87 Jet, Eric S. Perlman, Mihai Cara, Matthew Bourque, Raymond C. Simons

Aerospace, Physics, and Space Science Faculty Publications

During the last decade, M87's jet has been the site of an extraordinary variability event, with one knot (HST-1) increasing by over a factor 100 in brightness. Variability has also been seen on timescales of months in the nuclear flux. Here we discuss the optical-UV polarization and spectral variability of these components, which show vastly different behavior. HST-1 shows a highly significant correlation between flux and polarization, with P increasing from 20% at minimum to >40% at maximum, while the orientation of its electric vector stayed constant. HST-1's optical-UV spectrum is very hard (αUV-O 0.5, F ν ∞ ν-α), and …

On The Radio And Optical Luminosity Evolution Of Quasars, Jack Singal, V. Petrosian, A. Lawrence, L. Stawarz

Physics Faculty Publications

We calculate simultaneously the radio and optical luminosity evolutions of quasars, and the distribution in radio loudness R defined as the ratio of radio and optical luminosities, using a flux-limited data set containing 636 quasars with radio and optical fluxes from White et al. We first note that when dealing with multi-variate data it is imperative to first determine the true correlations among the variables, not those introduced by the observational selection effects, before obtaining the individual distributions of the variables. We use the methods developed by Efron and Petrosian which are designed to obtain unbiased correlations, distributions, and evolution …

Ordered Phases In Ruthenium Binary Alloys From High-Throughput First-Principles Calculations, Gus L. W. Hart, Lance J. Nelson, Michal Jahnátek, Ohad Levy, Roman V. Chepulskii, J. Xue, Stephano Curtarolo

Faculty Publications

Despite the increasing importance of ruthenium in numerous technological applications, e.g., catalysis and electronic devices, experimental and computational data on its binary alloys are sparse. In particular, data are scant on those binary systems believed to be phase-separating. We performed a comprehensive study of ruthenium binary systems with the 28 transition metals, using high-throughput first-principles calculations. These computations predict novel unsuspected compounds in 7 of the 16 binary systems previously believed to be phase-separating and in two of the three systems reported with only a high-temperature σ phase. They also predict a few unreported compounds in five additional systems and …

Analytic Derivative Couplings Between Configuration-Interaction-Singles States With Built-In Electron-Translation Factors For Translational Invariance, Shervin Fatehi, Ethan Alguire, Yihan Shao, Joseph Subotnik

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

We present a method for analytically calculating the derivative couplings between a pair of configuration-interaction-singles (CIS) excited states obtained in an atom-centered basis. Our theory is exact and has been derived using two completely independent approaches: one inspired by the Hellmann-Feynman theorem and the other following from direct differentiation. (The former is new, while the latter is in the spirit of existing approaches in the literature.) Our expression for the derivative couplings incorporates all Pulay effects associated with the use of an atom-centered basis, and the computational cost is minimal, roughly comparable to that of a single CIS energy gradient. …

Design And Synthesis Of Cationic Steroid Antimicrobial Compounds, Synthesis Of Glycolipids Recognized By Natural Killer T Cells And Development Of Tlr-1, Tlr-6 Heterodimer Binders And Studies Of Their Immunology Activities, Yanshu Feng

Theses and Dissertations

Cationic steroid antimicrobial agents (CSAs) are a family of bile acid derivatives. These compounds are amphiphilic and mimic endogenous antimicrobial peptides. The antimicrobial activities of CSA-13 have been investigated and due to portent bactericidal activities and low toxicity, a large amount of CSA-13 is demanded for clinic trails and other antimicrobial applications. During our studies, we optimized the synthetic route of CSA-13, so that it can be prepared at the kilogram, even in tons scale. We investigated three routes and one of them is suitable for industry, because only recrystallization is needed in the synthesis. Natural killer T cells (NKT …

A Learning Collaboratory: Improving Federal Climate Change Adaptation Planning, Alejandro E. Camacho

BYU Law Review

No abstract provided.

Addressing Global Climate Change In An Age Of Political Climate Change, Brigham Daniels

BYU Law Review

For a number of years, many within the environmental legal community have advocated an all-out attack strategy of forcing the United States to address climate change by bringing novel lawsuits under existing environmental laws. In 2007, with the seminal case of Massachusetts v. EPA, it appeared that those advocating this strategy had a winning game plan. That sense grew and solidified when the Obama Administration came to power. However, over the past several years, we have seen a countervailing movement embodied in a growing resentment towards EPA and climate change policy in general. This movement has mobilized into a powerful …

Collisional Reactivation Of Rift Margin Fracture Zones, Taiwan And The Taconic Allochthon, David C. Mirakian

Master's Theses

Chapter I. Transverse Topographic Development due to the Reactivation of a Partially-Subducted Fracture Zone: The Southwest Hsüehshan Range, Central Taiwan

Abstract — The southwest flank of the Hsüehshan Range is defined by a topographic break which cuts across regionally mapped structures in central Taiwan. The mountain front trends ~345°, slightly oblique to the Sanyi-Puli seismic zone which has been previously interpreted as a reactivated continental margin fracture zone. Structural data collected along the length of the topographic break reveal two populations of cross-cutting faults with distinct fault-zone materials and a series of southwest-plunging folds. Paleostress axes were reconstructed using the …

Testing The Limits Of Hyperspectral Airborne Remote Sensing By Mapping Eelgrass In Elkhorn Slough, Kelley J. Bostrom

Master's Theses

Seagrass ecosystems are a valuable resource, but vulnerable to changing conditions in the coastal ocean. Quantification of seagrass density and distribution from aerial imagery can be applied as a tool in resource management and ecosystem health and stability monitoring. This study investigates analytical methods for mapping eelgrass beds in an optically complex shallow, turbid estuary. Hyperspectral imagery (HSI) of Elkhorn Slough, CA was collected by the Spectroscopic Aerial Mapper with Onboard Navigation (SAMSON) instrument. In-situ data of water column and benthic optical properties and Hydrolight Radiative Transfer model were used to create a spectral library describing the reflectance of Elkhorn …

Adapting To Climate Change While Planning For Disaster: Footholds, Rope Lines, And The Iowa Floods, Robert R.M. Verchick, Abby Hall

BYU Law Review

No abstract provided.

Synthesis Of N-(Substituted Phenyl) Acetamides., Landon Zink

Undergraduate Honors Theses

No abstract.

Proposing A Path For Sustainability Curricula: Identifying Core Thinking And Learning Elements For Sustainability Higher Education, Timothy F. Botkin

Masters Theses, 2010-2019

Research indicates that sustainability higher education (SHE) has been promoted since the 1970s but has not achieved satisfactory progress in meeting original goals. Reflecting the evasive nature of sustainability as a goal, SHE programs appear stunted and there is little overall guidance with regard to curricula development. This dissertation addresses this issue by conducting a comprehensive literature research and sampling of those in sustainability post-graduate programs in an effort to determine an articulable set of core thinking and learning elements to assist in implementing SHE programs. Initial research identified fifteen core element candidates. These were incorporated into a survey sent …

Residential Solar Energy In The Valley: A Feasibility Assessment And Carbon Mitigation, Deanna Leigh Zimmerman

Masters Theses, 2010-2019

This project explores whether the Shenandoah Valley can achieve its 25x’25 goals in the residential sector using the two most feasible solar energy technologies, solar photovoltaic electric power production and solar thermal hot water generation. After a review of the barriers to the adoption of solar energy in households, the potential rates of adoption and energy output are estimated using U.S. Census data and Department of Energy data. Multiple scenarios are explored, including the “maximum theoretical” contribution of solar energy to the residential sector as well as scenarios of household behavior under different constraints. With respect to solar photovoltaic, it …

Integrated Waste Management As A Climate Change Stabilization Wedge For The Maletese Islands, Clyde Falzon

Masters Theses, 2010-2019

Planet Earth is finding difficulty in dealing with the continuous increase in anthropogenic greenhouse gas emissions. This is leading to change in climate which leads to extensive damage to communities, ecosystems and resources. This study is focussed on the waste sector which is the second largest greenhouse gas emitter in the Maltese islands after the energy (including transport) sector. Moreover, if practiced according to standards, waste management can lead to emission reduction. This work is based on the stabilisation wedges strategy and specifically focused on the integrated waste management wedge. Moreover in this work a life cycle assessment methodology is …

Synthesis Of Chemical Models Of Hydrolase Enzymes For Intramolecular Catalysis., Cornelius Ndi Ndi

Electronic Theses and Dissertations

Most nuclease enzymes can hydrolyze phosphoester bonds (in DNA and RNA) by using metal ions cofactors that coordinate and activate water molecules in the enzymes' active sites. However, there are some hydrolase enzymes (including nucleases) that can function without the aid of metal ions. 2,6-Di(1H-imidazol-2-yl)phenol, a model compound for hydrolase enzyme, was synthesized by the reaction between ethylenediamine and dimethyl-3-carboxysalicylate, initially resulting in the formation of diimidazoline. The diimidazoline was subsequently aromatized to the diimidazole by dehydrogenation over palladium. The overall reaction yield was low; therefore, other dehydrogenation transformation reactions were tried but all failed to improve the …

Survey Of Flavonoids And Their Distribution In Different Kinds Of Onions Using High Performance Liquid Chromatography And Gas Chromatography Mass Spectrometry., Archana Racharla

Electronic Theses and Dissertations

This research is done to determine the distribution of flavonoids in diverse varieties of onions (commercial and wild onions). Reflux extraction method was done on dried onions and the abstracts were analyzed subsequently by high performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GCMS). Statistical calculations were done to see if there are significant differences in the varieties of onions studied from the chromatographic profiles obtained. The chromatograms obtained were patterned using visual observations, scatter plot study, correlation co-efficient, and ANOVA to evaluate the significant difference of the distribution of flavonoids in varieties of onions. The organic white onions seem …

Fabrication Of Chemically Modified Nanometer-Sized Gold Electrodes And Their Application In Electrocatalysis At Pt Nanoparticles., Jude Lakbub

Electronic Theses and Dissertations

Hydrogen evolution via proton reduction occurs at a high rate at the surface of Pt than at Au electrodes. Using cyclic voltammetry, chemically modified nanometer-sized Au electrodes, prepared by the Laser-Assisted Puller Method, were employed to examine current amplification by electrocalysis at Pt nanoparticles adsorbed on the modified Au electrode surfaces. The electrodes were modified with Self-Assembled Monolayers (SAMs) of cysteamine and soaked in Pt colloid solutions overnight. Monitoring the decrements of the characteristic steady-state catalytic current for proton reduction indicated that aggregates of Pt nanoparticles are adsorbed on the cysteamine monolayers and desorb from them particle by particle. The …