Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

2012

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 19051 - 19080 of 19309

Full-Text Articles in Entire DC Network

Synthesis And Characterization Of Red And Near-Infrared Bodipy-Based Fluorophores For Various Biological Applications, Timsy Kaur Uppal Jan 2012

Synthesis And Characterization Of Red And Near-Infrared Bodipy-Based Fluorophores For Various Biological Applications, Timsy Kaur Uppal

LSU Doctoral Dissertations

ABSTRACT 4,4-Difluoro-3a,4a-diaza-s-indacene, better known as BODIPY® dyes, have attracted considerable attention due to their intriguing physicochemical and spectral properties, including high absorption coefficient, fluorescence quantum yield and good photochemical stability. Despite the recent progress achieved in this field, the synthesis of BODIPY derivatives that absorb and emit in the red- and NIR-region of the electromagnetic spectrum and their application to biomolecular targets, represents a long-standing challenge in BODIPY chemistry. This research work is therefore focused on the synthesis and characterization of red and NIR-emissive BODIPY-based fluorophores for various bioanalytical and biomedical applications. Chapter 1 of this dissertation represents a concise …

Go to article

Fabrication, Analysis, Application, And Characterization Of Core-Containing Microparticles And Hydrophilic Microfluidic Devices Produced Via The Primary- And In Situ Tertiary-Amine Catalyzed Michael Addition Of Multifunctional Thiols To Multifunctional Acrylates, Christopher O. Bounds Jan 2012

Fabrication, Analysis, Application, And Characterization Of Core-Containing Microparticles And Hydrophilic Microfluidic Devices Produced Via The Primary- And In Situ Tertiary-Amine Catalyzed Michael Addition Of Multifunctional Thiols To Multifunctional Acrylates, Christopher O. Bounds

LSU Doctoral Dissertations

The objective of this research was to investigate amine-catalyzed thiol-acrylate chemistry for various novel applications that could fully utilize the untapped potential of this useful and robust chemistry. The use of this chemistry in each application solved a problem, improved on a disadvantage of current technologies, and decreased the level of complexity in association with required time, cost, and/or preparation conditions. The first novel application conceived, applied, and analyzed was in the field of microencapsulation. A novel approach for the preparation of microparticles via a dispersion polymerization using the primary amine-catalyzed addition of a trithiol to a triacrylate was realized …

Go to article

Assessing Cost Efficiency And Economies Of Scale In The European Banking System, A Bayesian Stochastic Frontier Approach, Ana Maria Ichim Jan 2012

Assessing Cost Efficiency And Economies Of Scale In The European Banking System, A Bayesian Stochastic Frontier Approach, Ana Maria Ichim

LSU Doctoral Dissertations

Cost e_x000E_fficiency of banks is a key indicator that provides valuable insight to researchers and policymakers about the functioning of the _x000C_financial intermediation process, as well as, the overall performance of the entire financial system. This thesis focuses on the cost effi_x000E_ciency of the European banking market for which we identify fourteen nation-specific frontiers and also perform cross country comparisons under a common frontier assumption. Our interest in the subject is twofold. At the nation level, cost e_x000E_fficiency influences the relative competitiveness of banks, setting the profile of the national banking industry with direct implications on economic growth. At the …

Go to article

Conformance Testing Of Peer-To-Peer Systems Using Message Traffic Analysis, John Wesley Burris Jan 2012

Conformance Testing Of Peer-To-Peer Systems Using Message Traffic Analysis, John Wesley Burris

LSU Doctoral Dissertations

Peer-to-Peer architectures are used by a large number of distributed systems; however, the challenges such as maintaining a reliable and stable peer-to-peer network can make such networks undesirable for distributed systems. Peer-to-peer architectures are designed to be executed on systems with diverse hardware configurations, distant geographic locations, and varied, unpredictable Internet connectivity that make the software testing process difficult. This research defines a method for conformance testing peer-to-peer content distribution systems called “Method for Conformance Testing by Analyzing Message Activity” (MCTAMA). MCTAMA uses a common representation for describing the behavior of nodes during both design and deployment. ATAMA generates, evaluates …

Go to article

Microfabrication Of Conductive Polymer Nanocomposite For Sensor Applications, Chaoxuan Liu Jan 2012

Microfabrication Of Conductive Polymer Nanocomposite For Sensor Applications, Chaoxuan Liu

LSU Doctoral Dissertations

This dissertation developed novel microfabrication techniques of conductive polymer nanocomposite and utilized this material as a functional element for various physical sensor applications. Microstructures of nanocomposite were realized through novel microcontact printing and laser ablation assisted micropatterning processes. Prototype devices including large-strain strain sensor and highly-sensitive pressure sensor were demonstrated showing distinct advantages over existing technologies. The polymer nanocomposite used in this work comprised elastomer poly(dimexylsiloxane) (PDMS) as polymer matrix and multi-walled carbon nananotubes (MWCNTs) as a conductive nanofiller. To achieve uniform distribution of carbon nanotubes within the polymer, an optimized dispersion process was developed, featuring a strong organic solvent—chloroform, …

Go to article

Soil Accretion And Organic Carbon Accumulation In The Tidal Salt Marshes Of The Liaohe Delta, China, Nicholas Lawrence Yuknis Jan 2012

Soil Accretion And Organic Carbon Accumulation In The Tidal Salt Marshes Of The Liaohe Delta, China, Nicholas Lawrence Yuknis

LSU Master's Theses

Wetlands provide a multitude of functions to people and ecosystems and because of this, maintaining or increasing wetland area is important. Wetlands can be significant carbon sinks because of the relatively high primary productivity and slow decomposition of organic matter in these systems and can thus impact the global carbon cycle and potentially climate change. The marshes of the Liaohe Delta are the largest in Liaoning Province; however, very little research has been done in this area to determine the rate of accretion and organic carbon sequestration in the salt marshes there. By using Cs-137 and Pb-210 dating techniques and …

Go to article

Identification And Incorporation Of Quantitative Indicators Of Ecosystem Function Into Single-Species Fishery Stock Assessment Models And The Associated Biological Reference Points, Melissa Hedges Monk Jan 2012

Identification And Incorporation Of Quantitative Indicators Of Ecosystem Function Into Single-Species Fishery Stock Assessment Models And The Associated Biological Reference Points, Melissa Hedges Monk

LSU Doctoral Dissertations

The move towards an ecosystem approach to fisheries management requires baseline information on the biotic communities and an understanding of the interactions among species. The two objectives of this study were to describe the demersal fish community (DFC) associated with the northwestern Gulf shrimp trawl fishery, and to utilize a multispecies Lotka-Volterra model to examine possible community level effects of fishing. Community level effects include predator-prey interactions and the responses of fish in the same community to fishing pressure. The summer and fall Southeast Area Monitoring and Assessment Program (SEAMAP) bottomfish trawl surveys were used to identify spatial and temporal …

Go to article

A Numerical Investigation Of Apéry-Like Recursions And Related Picard-Fuchs Equations, Maiia J. Bakhova Jan 2012

A Numerical Investigation Of Apéry-Like Recursions And Related Picard-Fuchs Equations, Maiia J. Bakhova

LSU Doctoral Dissertations

In this work we investigate a generalization of a recursion which was used by Apery in his proof of irrationality of the zeta function values at 2 and 3. It is a continuation of the work of Zagier , who considered generalization of the first equation and numerically investigated it. The study is made for two generalizations of the second equation, one used the mirror symmetry idea from the theory of Calabi-Yau varieties and another worked with recursion. There were discovered connections between them.

Go to article

Continuum And Crystal Strain Gradient Plasticity With Energetic And Dissipative Length Scales, Danial Faghihi Shahrestani Jan 2012

Continuum And Crystal Strain Gradient Plasticity With Energetic And Dissipative Length Scales, Danial Faghihi Shahrestani

LSU Doctoral Dissertations

This work, standing as an attempt to understand and mathematically model the small scale materials thermal and mechanical responses by the aid of Materials Science fundamentals, Continuum Solid Mechanics, Misro-scale experimental observations, and Numerical methods. Since conventional continuum plasticity and heat transfer theories, based on the local thermodynamic equilibrium, do not account for the microstructural characteristics of materials, they cannot be used to adequately address the observed mechanical and thermal response of the micro-scale metallic structures. Some of these cases, which are considered in this dissertation, include the dependency of thin films strength on the width of the sample and …

Go to article

Energy, Environment, And Sustainability: A Hierarchical Analysis Of South Louisiana, Matthew Korbel Moerschbaecher Jan 2012

Energy, Environment, And Sustainability: A Hierarchical Analysis Of South Louisiana, Matthew Korbel Moerschbaecher

LSU Doctoral Dissertations

This dissertation details research into the sustainability of industrial, human, and natural systems in south Louisiana. Chapter 1 is a general introduction. Chapter 2 calculates the energy return on financial investment (EROFI) of oil and gas production in the ultra-deepwater Gulf of Mexico (GoM) in 2009 and the Macondo Prospect (Mississippi Canyon Block 252). I calculated a preliminary Energy Return on Investment (EROI) using a range of energy intensity ratios. The EROFI for ultra-deepwater oil and gas at the wellhead was roughly 0.85 gallons, per dollar. These estimates of EROI for 2009 ultra-deepwater oil and natural gas at the wellhead …

Go to article

Total Synthesis Of A Virotoxin And Analogs For Conformational Studies, Benson Jumba Edagwa Jan 2012

Total Synthesis Of A Virotoxin And Analogs For Conformational Studies, Benson Jumba Edagwa

LSU Doctoral Dissertations

This dissertation describes the first total synthesis of alloviroidin in trace amounts, along with that of three analogs containing L-proline (Pro), trans-3-hydroxyproline (3-Hyp) or cis-4-hydroxyproline (4-hyp) residue substituting for 2,3-trans-3,4-trans-dihydroxyproline in the natural product. We report herein an efficient strategy that provides a dipeptide containing a (2S,4S)-4,5-dihydroxyleucine (dihyLeu) residue, including a diastereoselective dihydroxylation. Nα-Carbobenzyloxy-(2S)-4,5-dehydroleucine was coupled with valine ethyl ester to give a dipeptide that was subjected to a Sharpless asymmetric dihydroxylation to introduce the diol. The relative configuration at C4 was assigned as S by X-ray crystallography after derivatization as an α-amino-γ-lactone hydrochloride salt. The preparation of the 2-(methylsulfonyl)tryptophan …

Go to article

Spatial Variability In Response Of Deltaic Baldcypress Forests To Hydrology And Climate, Som Bahadur Bohora Jan 2012

Spatial Variability In Response Of Deltaic Baldcypress Forests To Hydrology And Climate, Som Bahadur Bohora

LSU Master's Theses

Changing hydrology and climate have significantly altered ecologically significant cypress-tupelo forests in the deltaic plain of the Mississippi River. Though local responses of these swamps to hydrology are relatively well understood, broad-scale evaluation of ecological response differences of deltaic wetland forests has been limited by the lack of site-specific coupled hydrologic and ecological data. Baldcypress tree-rings from twenty-two sites were used to examine the responses of coastal swamp forests throughout the deltaic plain to environmental variables. The responses of these forests to environmental variables varied spatially; however, broad-scale measures of deltaic hydrology were more correlated with tree radial growth than …

Go to article

Evaluation Of The Depositional Environment Of The Eagle Ford Formation Using Well Log, Seismic, And Core Data In The Hawkville Trough, Lasalle And Mcmullen Counties, South Texas, Zachary Paul Hendershott Jan 2012

Evaluation Of The Depositional Environment Of The Eagle Ford Formation Using Well Log, Seismic, And Core Data In The Hawkville Trough, Lasalle And Mcmullen Counties, South Texas, Zachary Paul Hendershott

LSU Master's Theses

The Upper Cretaceous Eagle Ford Formation of South Texas records a mixed siliciclastic/carbonate depositional environment across the Late Cretaceous Platform of the Gulf of Mexico. During the Late Cretaceous, LaSalle and McMullen Counties was part of the Hawkville Trough, a wedged shaped region between the Edwards and Sligo carbonate reefs. Well logs from 21 wells and seismic data were used to construct structure and isopach maps of the Eagle Ford Formation throughout the Hawkville Trough. Only the unconformable bottom (Buda-Eagle Ford) and top (Eagle Ford-Austin Chalk) boundaries plus the conformable boundary between the upper and lower Eagle Ford can be …

Go to article

Function And Diversity Of The Ship, Trinity, And Tiger Shoal Complex, With Emphasis On Macrofauna And Spawning Blue Crabs (Callinectes Sapidus), Carey George Gelpi Jr. Jan 2012

Function And Diversity Of The Ship, Trinity, And Tiger Shoal Complex, With Emphasis On Macrofauna And Spawning Blue Crabs (Callinectes Sapidus), Carey George Gelpi Jr.

LSU Doctoral Dissertations

The ecological and economic value of sandy shoals off the Louisiana coast is not well understood. During three years of comprehensive benthic sampling and environmental measurements I studied the Ship, Trinity, Tiger Shoal Complex (STTSC), which comprises changing and discrete benthic habitats including high relief sandy shoals, and muddier, mostly deeper off-shoal areas, prone to hypoxia. Benthic macrofaunal assemblages of shoals included endemic species, and shoal communities were significantly different from each other and the muddier offshoal habitat, contributing to northern Gulf of Mexico (GoM) regional biodiversity. Sand percentage was the most influential environmental parameter shaping macrofaunal community composition across …

Go to article

Cluster Based Jamming And Countermeasures For Wireless Sensor Network Mac Protocols, David Trammell Jan 2012

Cluster Based Jamming And Countermeasures For Wireless Sensor Network Mac Protocols, David Trammell

LSU Doctoral Dissertations

A wireless sensor network (WSN) is a collection of wireless nodes, usually with limited computing resources and available energy. The medium access control layer (MAC layer) directly guides the radio hardware and manages access to the radio spectrum in controlled way. A top priority for a WSN MAC protocol is to conserve energy, however tailoring the algorithm for this purpose can create or expose a number of security vulnerabilities. In particular, a regular duty cycle makes a node vulnerable to periodic jamming attacks. This vulnerability limits the use of use of a WSN in applications requiring high levels of security. …

Go to article

A Thermodynamic Framework For The Modeling And Optimization Of Crystallization Processes, David John Widenski Jan 2012

A Thermodynamic Framework For The Modeling And Optimization Of Crystallization Processes, David John Widenski

LSU Doctoral Dissertations

Crystallization is a widely used chemical engineering separation unit operation process. Since this technique can produce high purity products it is used for the industrial production of many chemical compounds, such as pharmaceuticals, agrochemicals, and fine chemicals. The production of these products is a multi-million dollar industry. Any methods to improve the production of these products would be highly valued. Thus, the main objective of this work is to target model-based optimal strategies for crystallization operations specifically targeting crystal size and crystal size distribution (CSD). In particular, take the knowledge gained and translate it into an economically and practically feasible …

Go to article

On The Synthesis, Characterization, And Magnetization Of Ln-M-X (Ln = Lanthanide; M = Ti-Cr, Cu, Mo, Pd; X = Al, Ga) Intermetallics, Michael James Kangas Jan 2012

On The Synthesis, Characterization, And Magnetization Of Ln-M-X (Ln = Lanthanide; M = Ti-Cr, Cu, Mo, Pd; X = Al, Ga) Intermetallics, Michael James Kangas

LSU Doctoral Dissertations

The focus of the research presented herein was to grow single crystals of Ln-M-X (Ln = lanthanide; M = Ti-Cr, Cu, Mo, Pd; X = Al, Ga) intermetallic compounds and to characterize their crystal structures and physical properties. Overall, the flux growth technique facilitated a detailed analysis of previously known structure-types (LnM2Al20 (Ln = La, Ce, Pr, Yb; M = Ti, V, Cr), Ln6M4Al43 (Ln = Gd, Yb; M = Cr, Mo), and Yb2Pd3Ga9), as well as the synthesis and characterization of new compounds (LnCrxGa3 (Ln = Ho, Er; x ~ 0.13), YbCr2Al20-xFex (x ~ 0.2), Ln(Cu,Al,Ga)13-x, and Ln2PdGa12 (Ln …

Go to article

Integrating Tasks, Technology, And The Common Core Standards In The Algebra Ii Classroom, Beth Perkins Mcinnis Jan 2012

Integrating Tasks, Technology, And The Common Core Standards In The Algebra Ii Classroom, Beth Perkins Mcinnis

LSU Master's Theses

The Common Core State Standards for Mathematics were released in June of 2010. The standards were developed by a team of over 75 teachers and specialist in response to improve math education in the United States through more focused, coherent, rigorous standards to help our students be competitive in the 21st century. As of June 2012, 45 states had adopted the new standards which better coordinate what students at individual grade level should know and be able to do to in order to be college and career ready by grade twelve. With new computer based assessments being developed and set …

Go to article

Sediment Flux & Fate For A Large-Scale Diversion: The 2011 Mississippi River Flood, The Bonnet Carré Spillway, And The Implications For Coastal Restoration In South Louisiana, Jeffrey Bryant Fabre Jan 2012

Sediment Flux & Fate For A Large-Scale Diversion: The 2011 Mississippi River Flood, The Bonnet Carré Spillway, And The Implications For Coastal Restoration In South Louisiana, Jeffrey Bryant Fabre

LSU Master's Theses

Dams and hardened levees built by European settlers in the last two centuries have degraded or stopped the cyclic sedimentation patterns that built the Mississippi River Delta Plain over the past 7,000-8,000 years. Man-made diversions of sediment-laden river water along the lower Mississippi, operated during high water periods, are being considered as a primary mechanism for combating the land loss induced by rising sea-level and these modern controls. To date, no study has documented the sediment-delivery potential of a large man-made river diversion during a single high water event. In the spring of 2011, historic flooding on the Mississippi River …

Go to article

Exclusive Electroproduction Of Two Pions At Hera, H. Abramowicz, I. Abt, L. Adamczyk, M. Adamus, R. Aggarwal, S. Antonelli, P. Antonioli, A. Antonov, M. Arneodo, D. Ashery, V. Aushev, Y. Aushev, O. Bachynska, A. Bamberger, A. N. Barakbaev, G. Barbagli, G. Bari, F. Barreiro, N. Bartosik, D. Bartsch, M. Basile, O. Behnke, J. Behr, U. Behrens, L. Bellagamba, A. Bertolin, S. Bhadra, M. Bindi, C. Blohm, V. Bokhonov, T. Bołd, Margarita C. K. Mattingly Jan 2012

Exclusive Electroproduction Of Two Pions At Hera, H. Abramowicz, I. Abt, L. Adamczyk, M. Adamus, R. Aggarwal, S. Antonelli, P. Antonioli, A. Antonov, M. Arneodo, D. Ashery, V. Aushev, Y. Aushev, O. Bachynska, A. Bamberger, A. N. Barakbaev, G. Barbagli, G. Bari, F. Barreiro, N. Bartosik, D. Bartsch, M. Basile, O. Behnke, J. Behr, U. Behrens, L. Bellagamba, A. Bertolin, S. Bhadra, M. Bindi, C. Blohm, V. Bokhonov, T. Bołd, Margarita C. K. Mattingly

Faculty Publications

The exclusive electroproduction of two pions in the mass range 0.4

Go to article

Effects Of Walnut Consumption On Cognitive Performance In Young Adults, Peter Pribis, Rudolph N. Bailey, Andrew A. Russell, Marcia A. Kilsby, Magaly Hernandez, Winston J. Craig, Tevni Grajales, David J. Shavlik, Joan Sabatè Jan 2012

Effects Of Walnut Consumption On Cognitive Performance In Young Adults, Peter Pribis, Rudolph N. Bailey, Andrew A. Russell, Marcia A. Kilsby, Magaly Hernandez, Winston J. Craig, Tevni Grajales, David J. Shavlik, Joan Sabatè

Faculty Publications

Walnuts contain a number of potentially neuroprotective compounds like vitamin E, folate, melatonin, several antioxidative polyphenols and significant amounts of n-3 α-linolenic fatty acid. The present study sought to determine the effect of walnuts on verbal and non-verbal reasoning, memory and mood. A total of sixty-four college students were randomly assigned to two treatment sequences in a crossover fashion: walnuts-placebo or placebo-walnuts. Baseline data were collected for non-verbal reasoning, verbal reasoning, memory and mood states. Data were collected again after 8 weeks of intervention. After 6 weeks of washout, the intervention groups followed the diets in reverse order. Data were …

Go to article

Combined Inclusive Diffractive Cross Sections Measured With Forward Proton Spectrometers In Deep Inelastic Ep Scattering At Hera, F. D. Aaron, H. Abramowicz, I. Abt, L. Adamczyk, M. Adamus, R. Aggarwal, C. Alexa, V. Andreev, S. Antonelli, P. Antonioli, A. Antonov, M. Arneodo, O. Arslan, V. Aushev, Y. Aushev, O. Bachynska, S. Backovic, A. Baghdasaryan, S. Baghdasaryan, A. Bamberger, A. N. Barakbaev, G. Barbagli, G. Bari, F. Barreiro, E. Barrelet, W. Bartel, N. Bartosik, D. Bartsch, M. Basile, K. Begzsuren, O. Behnke, Margarita C. K. Mattingly Jan 2012

Combined Inclusive Diffractive Cross Sections Measured With Forward Proton Spectrometers In Deep Inelastic Ep Scattering At Hera, F. D. Aaron, H. Abramowicz, I. Abt, L. Adamczyk, M. Adamus, R. Aggarwal, C. Alexa, V. Andreev, S. Antonelli, P. Antonioli, A. Antonov, M. Arneodo, O. Arslan, V. Aushev, Y. Aushev, O. Bachynska, S. Backovic, A. Baghdasaryan, S. Baghdasaryan, A. Bamberger, A. N. Barakbaev, G. Barbagli, G. Bari, F. Barreiro, E. Barrelet, W. Bartel, N. Bartosik, D. Bartsch, M. Basile, K. Begzsuren, O. Behnke, Margarita C. K. Mattingly

Faculty Publications

A combination of the inclusive diffractive cross section measurements made by the H1 and ZEUS Collaborations at HERA is presented. The analysis uses samples of diffractive deep inelastic ep scattering data at a centre-of-mass energy √s= 318 Gev where leading protons are detected by dedicated spectrometers. Correlations of systematic uncertainties are taken into account, resulting in an improved precision of the cross section measurement which reaches 6 % for the most precise points. The combined data cover the range 2.5 < Q2 < 200 GeV2 in photon virtuality, 0.00035 < xP < 0.09 in proton fractional momentum loss, 0.09 <{pipe}t{pipe}< 0.55 GeV2 in squared four-momentum transfer at the proton vertex and 0.0018 < β

Go to article

On Fundamental Groups Of Quotient Spaces, Jack S. Calcut, Robert E. Gompf, John D. Mccarthy Jan 2012

On Fundamental Groups Of Quotient Spaces, Jack S. Calcut, Robert E. Gompf, John D. Mccarthy

Faculty & Staff Scholarship

In classical covering space theory, a covering map induces an injection of fundamental groups. This paper reveals a dual property for certain quotient maps having connected fibers, with applications to orbit spaces of vector fields and leaf spaces in general.

Go to article

An Introduction To Ecology Of Infectious Diseases - Oysters And Estuaries, Eileen E. Hofmann, Susan E. Ford Jan 2012

An Introduction To Ecology Of Infectious Diseases - Oysters And Estuaries, Eileen E. Hofmann, Susan E. Ford

OES Faculty Publications

Infectious diseases are recognized as an important factor regulating marine ecosystems (Harvell et al., 1999, 2002, 2004; Porter et al., 2001; McCallum et al., 2004; Ward and Lafferty, 2004; Stewart et al., 2008; Bienfang et al., 2011). Many of the organisms affected by marine diseases have important ecological roles in estuarine and coastal environments and some are also commercially important. Outbreaks of infectious diseases in these environments, referred to as epizootics, can produce significant population declines and extinctions, both of which threaten biodiversity, food web interactions, and ecosystem productivity (Harvell et al., 2002, 2004).

Go to article

On The Skewness Of Order Statistics With Applications, Subhash C. Kochar, Maochao Xu Jan 2012

On The Skewness Of Order Statistics With Applications, Subhash C. Kochar, Maochao Xu

Mathematics and Statistics Faculty Publications and Presentations

Order statistics from heterogenous samples have been extensively studied in the literature. However, most of the work focused on the effect of heterogeneity on the magnitude and dispersion of order statistics. In this paper, we study the skewness of order statistics from heterogeneous samples in the sense of star order. The main results extended the results in Kochar and Xu (2009, 2011). Examples and applications in statistical inference are highlighted.

Go to article

A Locking-Free Hp Dpg Method For Linear Elasticity With Symmetric Stresses, Jamie Bramwell, Leszek Demkowicz, Jay Gopalakrishnan, Weifeng Qiu Jan 2012

A Locking-Free Hp Dpg Method For Linear Elasticity With Symmetric Stresses, Jamie Bramwell, Leszek Demkowicz, Jay Gopalakrishnan, Weifeng Qiu

Mathematics and Statistics Faculty Publications and Presentations

We present two new methods for linear elasticity that simultaneously yield stress and displacement approximations of optimal accuracy in both the mesh size h and polynomial degree p. This is achieved within the recently developed discontinuous Petrov- Galerkin (DPG) framework. In this framework, both the stress and the displacement ap- proximations are discontinuous across element interfaces. We study locking-free convergence properties and the interrelationships between the two DPG methods.

Go to article

Wavenumber Explicit Analysis Of A Dpg Method For The Multidimensional Helmholtz Equation, Leszek Demkowicz, Jay Gopalakrishnan, Ignacio Muga, Jeffrey Zitelli Jan 2012

Wavenumber Explicit Analysis Of A Dpg Method For The Multidimensional Helmholtz Equation, Leszek Demkowicz, Jay Gopalakrishnan, Ignacio Muga, Jeffrey Zitelli

Mathematics and Statistics Faculty Publications and Presentations

We study the properties of a novel discontinuous Petrov Galerkin (DPG) method for acoustic wave propagation. The method yields Hermitian positive definite matrices and has good pre-asymptotic stability properties. Numerically, we find that the method exhibits negligible phase errors (otherwise known as pollution errors) even in the lowest order case. Theoretically, we are able to prove error estimates that explicitly show the dependencies with respect to the wavenumber ω, the mesh size h, and the polynomial degree p. But the current state of the theory does not fully explain the remarkably good numerical phase errors. Theoretically, comparisons are made with …

Go to article

Understanding Multidigit Whole Numbers: The Role Of Knowledge Components, Connections, And Context In Understanding Regrouping 3+-Digit Numbers, Eva Thanheiser Jan 2012

Understanding Multidigit Whole Numbers: The Role Of Knowledge Components, Connections, And Context In Understanding Regrouping 3+-Digit Numbers, Eva Thanheiser

Mathematics and Statistics Faculty Publications and Presentations

This case study of a PST's understanding of regrouping with multidigit whole numbers in base-10 and non-base-10 contexts shows that although she seems to have all the knowledge elements necessary to give a conceptually based explanation of regrouping in the context of 3-digit numbers, she is unable to do so. This inability may be due to a lack of connections among various knowledge components (conceptual knowledge) or a lack of connections between knowledge components and context (strategic knowledge). Although she exhibited both conceptual and strategic knowledge of numbers while regrouping 2-digit numbers, her struggles in explaining regrouping 3-digit numbers in …

Go to article

Benchmark Results For Testing Adaptive Finite Element Eigenvalue Procedures Ii (Cluster Robust Eigenvector And Eigenvalue Estimates), Stefano Giani, Luka Grubisic, Jeffrey S. Ovall Jan 2012

Benchmark Results For Testing Adaptive Finite Element Eigenvalue Procedures Ii (Cluster Robust Eigenvector And Eigenvalue Estimates), Stefano Giani, Luka Grubisic, Jeffrey S. Ovall

Mathematics and Statistics Faculty Publications and Presentations

As a model benchmark problem for this study we consider a highly singular transmission type eigenvalue problem which we study in detail both analytically as well as numerically. In order to justify our claim of cluster robust and highly accurate approximation of a selected groups of eigenvalues and associated eigenfunctions, we give a new analysis of a class of direct residual eigenspace/vector approximation estimates. Unlike in the first part of the paper, we now use conforming higher order finite elements, since the canonical choice of an appropriate norm to measure eigenvector approximation by discontinuous Galerkin methods is an open problem.

Go to article

The Impact Of Socioscientific Issues Based Curriculum Involving Environmental Outdoor Education For Fourth Grade Students, Karey Burek Jan 2012

The Impact Of Socioscientific Issues Based Curriculum Involving Environmental Outdoor Education For Fourth Grade Students, Karey Burek

USF Tampa Graduate Theses and Dissertations

There is a divide between what students are being taught within the science classroom and what they experience out in the real world. This study sought to explore possible relationships between a socioscientific issues embedded curriculum and outcome variables addressing environmental attitude and knowledge, oral and written argumentation and critical thinking skills. Both quantitative and qualitative methods were used to examine both within and between class differences as well as individual differences between the beginning and end of a semester of elementary school. Results indicated that socioscientific issues assist students in developing their critical thinking skills while also providing students …

Go to article

First Prev Next Last