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2008

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Determining The Relative Efficacy Of Reciprocal And Non-Reciprocal Peer Tutoring For Students Identified As At-Risk For Academic Failure, Keri F. Menesses Jan 2008

Determining The Relative Efficacy Of Reciprocal And Non-Reciprocal Peer Tutoring For Students Identified As At-Risk For Academic Failure, Keri F. Menesses

LSU Master's Theses

The current study directly compared the academic and social gains of reciprocal peer tutoring, non-reciprocal peer tutoring, and traditional classroom instruction with elementary students. Participants included 59 students who performed below-average on class-wide screenings using curriculum-based measurement math probes. Students involved in peer tutoring were trained to tutor basic math facts using a constant time delay procedure. Both types of peer tutoring produced significantly larger academic gains than traditional classroom instruction; the two types of tutoring produced comparable academic and social results, although reciprocal tutoring resulted in marginally larger academic gains. Reciprocal peer tutoring is recommended based on the fact …

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Dosimetry Intercomparison Using A 35-Kev X-Ray Synchrotron Beam, Scott Oves Jan 2008

Dosimetry Intercomparison Using A 35-Kev X-Ray Synchrotron Beam, Scott Oves

LSU Master's Theses

Significance: Photon activated Auger electron therapy utilizes a keV-ranged, monoenergetic x-ray beam, and radiobiological and animal experiments studying this therapy require accurate dosimetry techniques. However, there exist few dosimetry protocols for low-energy x-ray beams. This research intended to use the CAMD synchrotron as a source of monochromatic, 35-keV x-rays and test dosimetry techniques of film and ion chamber. The hypothesis of my research was that depth-dose measured in a PMMA phantom using an air-equivalent ionization chamber and radiochromic film dosimeters in a PMMA phantom irradiated by a 35-keV, monochromatic x-ray beam will agree to within 5% of each other and …

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Determination Of Ctv-To-Itv Margin For Free-Breathing Respiratory-Gated Treatments Using 4dct And The Novalis Exactrac Gating System With Implanted Fiducials, Jason Edward Matney Jan 2008

Determination Of Ctv-To-Itv Margin For Free-Breathing Respiratory-Gated Treatments Using 4dct And The Novalis Exactrac Gating System With Implanted Fiducials, Jason Edward Matney

LSU Master's Theses

The purpose of this project was to investigate the interplay between gating window characteristics and target margin required to compensate for residual motion during the gating window. This project investigated the accuracy of ExacTrac and 4DCT imaging localizing an implanted coil at various phases of respiration. Radiochromic film measured delivered dose patterns for selected gating intervals over a variety of respiratory patterns. In order to establish accurate dosimetry, this project implemented and tested an EBT radiochromic film dosimetry system. Film testing showed that the performance of a medical grade Vidar Dosimetry Pro radiographic film scanner and an Epson V700 Photo …

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Nonperturbative Dynamics Of Strong Interactions From Gauge/Gravity Duality, Hovhannes Roman Grigoryan Jan 2008

Nonperturbative Dynamics Of Strong Interactions From Gauge/Gravity Duality, Hovhannes Roman Grigoryan

LSU Doctoral Dissertations

This thesis studies important dynamical observables of strong interactions such as form factors. It is known that Quantum Chromodynamics (QCD) is a theory which describes strong interactions. For large energies, one can apply perturbative techniques to solve some of the QCD problems. However, for low energies QCD enters into the nonperturbative regime, where different analytical or numerical tools have to be applied to solve problems of strong interactions. The holographic dual model of QCD is such an analytical tool that allows one to solve some nonperturbative QCD problems by translating them into a dual five-dimensional theory defined on some warped …

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Microassembly Technology For Modular, Polymer Microfluidic Devices, Byoung Hee You Jan 2008

Microassembly Technology For Modular, Polymer Microfluidic Devices, Byoung Hee You

LSU Doctoral Dissertations

Assembly of modular, polymer microfluidic devices with different functions to obtain more capable instruments may significantly expand the options available for detection and diagnosis of disease through DNA analysis and proteomics. For connecting modular devices, precise, passive alignment structures can be used to prevent infinitesimal motions between the devices and minimize misalignment. The motion and constraint of passive alignment structures were analyzed using screw theory. A combination of three v-groove and hemisphere-tipped post joints constrained all degrees of freedom of the two mating modules without overconstraint. Simulations and experiments were performed to assess the predictability of dimensional and location variations …

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Bioanalytical Methods For Studies Of Homocysteine And Novel Cardiovascular Disease Indicators, Arther T. Gates Jan 2008

Bioanalytical Methods For Studies Of Homocysteine And Novel Cardiovascular Disease Indicators, Arther T. Gates

LSU Doctoral Dissertations

This dissertation explores the development of analytical methods for studies of CVD biomarkers and related biomolecular indicators. Initially, spectroscopic studies were conducted to investigate the chemical reactivity of homocysteine (Hcy), an independent CVD risk factor and serological biomarker. Consequently, we proposed an alternate theory for in vivo Hcy clearance based on spontaneous pyridoxal tetrahydrothiazine (PT) formation from Hcy and pyridoxal. The validity of PT-assisted Hcy clearance was further evaluated by use of capillary electrophoretic methods, which allowed rapid monitoring of protein oligomerization in PT-protein reaction mixtures. The results of these studies suggest that PT formation is a plausible mechanism for …

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Opportunities And Challenges Associated With Development Of Wood Biomass Energy Production In Louisiana, Anil Raj Kizhakkepurakkal Jan 2008

Opportunities And Challenges Associated With Development Of Wood Biomass Energy Production In Louisiana, Anil Raj Kizhakkepurakkal

LSU Master's Theses

Wood residue produced by forest products industry has been recognized as a potential fuel that can generate energy to run the industry. A survey was done among forest products industry to get a general idea about energy produced from woody biomass created from forest industry in Louisiana, USA. The industry was classified into primary and secondary forest products industry. The study provided information regarding utilization and wastage of wood residue. Survey response rate was 25 percent. It addressed problems faced by wood residue energy development and came up with solution to solve them. When survey results were compared to previous …

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An Investigation Into Fuel Cells And Flow Cytometers Optimal Design, Etim Sunday Udoetok Jan 2008

An Investigation Into Fuel Cells And Flow Cytometers Optimal Design, Etim Sunday Udoetok

LSU Doctoral Dissertations

The aim of the fuel cells part of this project was to investigate the performance of Proton Exchange Membrane Fuel Cells and closely related fuel cell types like the Alkaline Fuel Cells and Phosphoric Acid Fuel Cells. The investigation involved understanding the performance of fuel cells, addressing the shortcomings of currently used designs, and finding new methods for improving the performance of fuel cells. CFD was used to study flow channels and information learned from the study was used to design a new and improved flow channel. A prototype of the new design was fabricated, tested and found to perform …

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The Construct Validity Of The Clinical Assessment Of Working Memory Ability, Benjamin David Hill Jan 2008

The Construct Validity Of The Clinical Assessment Of Working Memory Ability, Benjamin David Hill

LSU Doctoral Dissertations

Working memory is the cognitive ability to hold a discrete amount of information in mind in an accessible state for utilization in mental tasks. This cognitive ability is impaired in many clinical populations. There have been a number of theoretical shifts in the way that working memory is conceptualized and assessed in the experimental literature. The purpose of this study was to determine whether the Working Memory Indices (and their component subtests) from the WAIS-III and WMS-III accurately assess the working memory construct as it is currently defined in the experimental cognitive literature. Results generally supported the construct validity of …

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Dynamic Workflow Management For Large Scale Scientific Applications, Emir Mahmut Bahsi Jan 2008

Dynamic Workflow Management For Large Scale Scientific Applications, Emir Mahmut Bahsi

LSU Master's Theses

The increasing computational and data requirements of scientific applications have made the usage of large clustered systems as well as distributed resources inevitable. Although executing large applications in these environments brings increased performance, the automation of the process becomes more and more challenging. The use of complex workflow management systems has been a viable solution for this automation process. In this thesis, we study a broad range of workflow management tools and compare their capabilities especially in terms of dynamic and conditional structures they support, which are crucial for the automation of complex applications. We then apply some of these …

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The Role Of Attentional Focus In Event-Based Prospective Memory, Jill Shelton Jan 2008

The Role Of Attentional Focus In Event-Based Prospective Memory, Jill Shelton

LSU Doctoral Dissertations

Shelton, Jill, B.S., University of Tennessee-Chattanooga, 2001 M.S., University of Tennessee-Chattanooga, 2003 Doctor of Philosophy, Summer Commencement, 2008 Major: Psychology The Role of Attentional Focus in Event-based Prospective Memory. Dissertation directed by Professor Emily Elliott Pages in dissertation, 59. Words in abstract 188. ABSTRACT Two experiments were conducted to investigate how attentional resources are utilized in event-based prospective memory (PM). A PM component (make a designated response when you see a bird word) was embedded in a living/non-living judgment task (Experiment 1) and a recall task that required participants to alphabetically re-order sets of items (Experiment 2). One hypothesis predicts …

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Komatiitic Flows Of The Pioneer Ultramafic Complex Of The 3.3ga Weltevreden Formation, Barberton Greenstone Belt, South Africa: Stratigraphy, Petrology, And Geochemistry, Marc Romain Cooper Jan 2008

Komatiitic Flows Of The Pioneer Ultramafic Complex Of The 3.3ga Weltevreden Formation, Barberton Greenstone Belt, South Africa: Stratigraphy, Petrology, And Geochemistry, Marc Romain Cooper

LSU Master's Theses

The 3.29 Ga Pioneer Ultramafic Complex (WPC) is a 1 km thick east-northeast trending tilted (90° dip) section of layered ultramafic rock in the Weltevreden Formation in the west-northwest region of the Barberton Greenstone Belt (BGB). It was originally interpreted as an intrusive complex with slaty zones that have a linear horizontal fabric produced by shear. However, a recent study identifies these slaty zones as komatiitic tuffs and attributes their horizontal fabric to plane and cross bedding. The present study suggests the non-slaty zones are extrusive komatiitic flows with abundant pyroxene spinifex tops, normal volcanic textures and crystal sizes, and …

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Stochastic And Copula Models For Credit Derivatives, Chao Meng Jan 2008

Stochastic And Copula Models For Credit Derivatives, Chao Meng

LSU Doctoral Dissertations

We prove results relating to the exit time of a stochastic process from a region in N-dimensional space. We compute certain stochastic integrals involving the exit time. Taking a Gaussian copula model for the hitting time behavior, we prove several results on the sensitivity of quantities connected with the hitting times to parameters of the model, as well as the large-N behavior. We discuss the relationship of these results to certain credit derivative instruments. Relevant simulations are presented.

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Design Of A Fully Autonomous Mobile Pipeline Exploration Robot (Famper), Jong-Hoon Kim Jan 2008

Design Of A Fully Autonomous Mobile Pipeline Exploration Robot (Famper), Jong-Hoon Kim

LSU Master's Theses

Pipelines have been an integral part of our constructions for many centuries. However, need to be maintained, and the cost of maintenance continues to increase. Robots have been considered as an attractive alternative, and many different types of pipeline robots have been proposed in the past. Unfortunately many of them work under only very restricted environments such as customized pipelines, often have no vertical mobility, or can traverse through only a simple pipeline structure due to wired control. This thesis presents the design and implementation of a robot based on novel idea we call “caterpillar navigational mechanism”. A Fully Autonomous …

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Nanoclay Reinforced Polymer Composite And Its Application To Hybrid Composite Structures, Gefu Ji Jan 2008

Nanoclay Reinforced Polymer Composite And Its Application To Hybrid Composite Structures, Gefu Ji

LSU Master's Theses

The purpose of this study was to find the optimum mixing technique that leads to maximum gain in mechanical, thermal, and fire-retardant properties of vinyl ester based nanocomposites. Specifically, five combinations of incremental mixing intensity were applied to five groups of samples that were made of vinyl ester resin reinforced by 1 wt. % of montmorillonite (MMT). Changes in mechanical properties associated with each mixing combination were examined through a variety of tests, which were low velocity impact test, bending test, compression test, and dynamic mechanical analysis (DMA). Additionally, changes in thermal properties (e.g., thermal diffusivity, glass transition temperature) and …

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Assessment Of Oxygen Sources And Sinks In The Northern Gulf Of Mexico Using Stable Oxygen Isotopes, Zoraida Jazmin Quinones-Rivera Jan 2008

Assessment Of Oxygen Sources And Sinks In The Northern Gulf Of Mexico Using Stable Oxygen Isotopes, Zoraida Jazmin Quinones-Rivera

LSU Doctoral Dissertations

Coastal hypoxia (< 2 mg O2L-1) represents a global problem that continues to worsen as nutrient fluxes to these areas increase. The second largest zone of human-induced hypoxia is located on the Louisiana continental shelf where hypoxic bottom waters commonly occur during summertime. This region is strongly impacted by the large flux of freshwater and nutrients from the Mississippi River, which influences both biological and physical processes that control oxygen dynamics. Yet, based on oxygen concentration measurements alone, it is difficult to separate the effects of biological factors from physical factors. To address this problem, I used a dual budget approach to assess the importance of oxygen sources and sinks on the Louisiana continental shelf. The dual budget was based on using stable oxygen isotopes (ä18O) in combination with conventional oxygen concentration measurements. To analyze temporal trends, surface and bottom water samples were collected monthly between July 2001 and July 2003 along an onshore-offshore transect. For better spatial resolution, shelfwide sampling was conducted extending from the Mississippi River Delta to the Louisiana-Texas border in the month of July of 2001, 2002, and 2003. Oxygen saturations values ranged between 180% at the surface and almost 0% close to the bottom with a corresponding range of ä18O values from 15‰ to 50‰. Biological parameters were important during all seasons for surface oxygen dynamics. The effects of physical factors were less apparent, except during severe physical disturbances. Bottom water oxygen dynamics showed clear seasonal signals of high oxygen depletion and larger contributions of benthic respiration during the summer, which corresponded to the strong stratification of the water column. In bottom waters, summer oxygen depletion was predominantly due to benthic respiration, accounting for about 73%, 80% and 60% of the total oxygen loss for 2001, 2002 and 2003 respectively. Model estimates of production/respiration (P/R) ratio during the July shelfwide cruises indicated that surface waters were productive with an average calculated P/R above 1. Depth stratified sampling (5 m intervals), which started in July 2002, showed that productivity in the mixed layer (5 to 10 m) was not homogeneous. Calculated P/R exceeded 1 only in the surface layer, while at 5 m P/R was approximately 1 and at a depth of 10 m, P/R was less than 1. Additionally, hypoxic conditions were only detected within 5 m of the bottom sediments. The dual budget approach yielded new estimates of productivity dynamics in surface waters and of sediment oxygen demand in bottom waters. For the first time, this study provided routine insight into productivity and respiration dynamics over large temporal and spatial scales. This could not have been accomplished using traditional methods because they commonly rely on time-consuming incubations. The study has shown that respiration dynamics in bottom waters vary seasonally with higher contribution of benthic respiration during stratified summer conditions and prevalent water column respiration during fall and winter. In contrast, seasonality in surface waters was less pronounced as productivity was more dependent on (salinity-inferred) nutrient supply than climatic forcing.

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A Capacity-Approaching Coded Modulation Scheme For Non-Coherent Fading Channels, Youngjeon Cho Jan 2008

A Capacity-Approaching Coded Modulation Scheme For Non-Coherent Fading Channels, Youngjeon Cho

LSU Master's Theses

Approaching the Shannon limit of the communication channels has been studied by many researchers to efficiently and reliably transmit data through the channels. To solve this problem, various methods and schemes have been proposed for approaching the theoretical limit for Shannon’s channel capacity. Among them, both low-density parity check (LDPC) codes and Turbo codes have been proposed to minimize the bit error rate (BER). Therefore, understanding of LDPC codes and Turbo codes is useful for their applications in modern communication systems. The study about non-coherent channels, which do not require explicit knowledge or estimation of the channel state information, has …

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The "Stern Review" And Its Critics: Implications For The Theory And Practice Of Benefit-Cost Analysis, Daniel H. Cole Jan 2008

The "Stern Review" And Its Critics: Implications For The Theory And Practice Of Benefit-Cost Analysis, Daniel H. Cole

Articles by Maurer Faculty

The UK's Treasury's "Stern Review: The Economics of Climate Change" (Oct. 2006) reached dramatically different conclusions and policy recommendations than most earlier economic analyses of climate change. It found that the costs of climate change, as well as the potential net benefits of greenhouse gas reductions, were much higher that previously estimated, and consequently recommended more rapid and extensive cuts in emissions than other economist analysts. The Stern Review estimated that a 1% annual investment of global GDP in mitigation could prevent a 5% (or more) reduction in annual global GDP from climate change harm, forever. A number of prominent …

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Louis Aragon And Pierre Drieu La Rochelle: Servility And Subversion, Oana Carmina Cimpean Jan 2008

Louis Aragon And Pierre Drieu La Rochelle: Servility And Subversion, Oana Carmina Cimpean

LSU Doctoral Dissertations

This dissertation addresses the use of literature in support of political ideologies, starting from the cases of Louis Aragon and Pierre Drieu La Rochelle. Aragon and Drieu wrote extensively about man’s alienation in the modern world and, more importantly, about the possibility of overcoming that alienation. Both argued for the creation of a new man who could erect a new world on the ruins of the old. Though Aragon was a communist and Drieu a fascist, they shared an apocalyptic view of the world and believed themselves to be living in the last stage of history, the prelude to a …

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The Synthesis Of Water Soluble N-Acyl Chitosan Derivatives For Characterization As Antibacterial Agents, Lakia Monique Champagne Jan 2008

The Synthesis Of Water Soluble N-Acyl Chitosan Derivatives For Characterization As Antibacterial Agents, Lakia Monique Champagne

LSU Doctoral Dissertations

Currently, natural polysaccharides are being utilized increasingly in the markets because they exhibit biodegradability, biocompatibility, versatility, and are found abundant in nature. The diversity of natural polysaccharides provides the chemist with a broad spectrum of raw materials that can be used in many biological applications. Chitosan is a natural polysaccharide that possesses excellent biological properties. It has been recognized for its antibacterial activity, in that it is destructive towards the bacterium Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The antibacterial property of chitosan can be enhanced by changing the hydrophobic/hydrophilic nature of the polysaccharide backbone. This research entails …

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Exploration Of New Ternary Gallides And Investigation Of Their Structure-Property Relationships, Jung Young Cho Jan 2008

Exploration Of New Ternary Gallides And Investigation Of Their Structure-Property Relationships, Jung Young Cho

LSU Doctoral Dissertations

This dissertation focuses on the investigation of new ternary intermetallic gallides, which may exhibit exotic physical properties such as heavy-fermion behavior, large magnetoresistance, and even superconductivity. In particular, the Ln-Cu-Ga (Ln = lanthanides) system has been systematically investigated by changing a reaction ratio and/or using a different temperature profile to optimize desired phases. Single crystals of Ln2MGa12 (Ln = La, Ce; M = Ni, Cu) have been synthesized using Ga flux and compared to their Pd analogues. Interestingly, Ce2MGa12 (M = Ni, Cu) show enhanced Sommerfeld coefficient of ¡Ö 191 mJmol-1K-2 and ¡Ö 69 mJmol-1K-2 for Ni and Cu compounds, …

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Towards An Extended Microscopic Theory For Upper-Fp-Shell Nuclei, Kalin Drumev Jan 2008

Towards An Extended Microscopic Theory For Upper-Fp-Shell Nuclei, Kalin Drumev

LSU Doctoral Dissertations

An extended SU(3) shell model that for the first time explicitly includes particles from the unique-parity levels in nuclei is introduced. Its relevance is established through calculations performed with realistic interactions for a group of upper fp-shell isotopes where valence nucleons beyond the N=28=Z core occupy levels of the normal-parity upper $fp$-shell ($f_{5/2},p_{3/2},p_{1/2}$) and the unique-parity $g_{9/2}$ intruder configuration. Specifically, the outcome suggests that the pseudo-SU(3) symmetry is quite good throughout the region and that only part of the configurations are relevant for the structure of the low-lying states. The levels of the upper $fp$-shell are handled within the framework …

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Syntheses Of Trimethylamine- And Phosphonate- Substituted Carboranylporphyrins For Application In Boron Neutron Cancer Therapy, Michael William Easson Jan 2008

Syntheses Of Trimethylamine- And Phosphonate- Substituted Carboranylporphyrins For Application In Boron Neutron Cancer Therapy, Michael William Easson

LSU Doctoral Dissertations

Chapter 1 contains an introduction to porphyrins and carboranylporphyrins, including their physical properties, history, methods of synthesis, medicinal applications, and an overview of recently published compounds. Chapter 2 contains the total synthesis of a series of trimethylamine- and phosphonate-substituted carboranylporphyrins for application in boron neutron capture therapy (BNCT), including characterization by proton nuclear magnetic resonance spectroscopy, matrix-assisted time-of-flight mass spectroscopy, high resolution mass spectroscopy, UV-Vis spectrophotometry, X-ray crystallography, and melting point apparatus. Chapter 3 contains synthetic methods which were investigated as alternate routes to porphyrin synthesis and functionalization. Chapter 4 presents the in vitro biological evaluation of trimethylamine- and phosphonate-substituted …

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Factors That Influence Traditional-Age College Students To Re-Enroll In Their Third Year At A Research Extensive University In The Southern Region Of The United States, Joseph M. Lutta Jan 2008

Factors That Influence Traditional-Age College Students To Re-Enroll In Their Third Year At A Research Extensive University In The Southern Region Of The United States, Joseph M. Lutta

LSU Doctoral Dissertations

Student retention is of policy significance to higher education systems. In the United States, student retention is a major problem in higher education affecting students, universities, and society. Most of the research on student retention has focused on first-year students. Little is known about the retention of college students after their first year. The primary purpose of this study was to determine the influence of selected demographic and academic characteristics on the decision of traditional-age, undergraduate students to re-enroll at a research-extensive university. The population was defined as all traditional-age undergraduate students who entered the selected university during the fall …

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Lattice Boltzmann Modeling For Mass Transport Equations In Porous Media, Borja Servan Camas Jan 2008

Lattice Boltzmann Modeling For Mass Transport Equations In Porous Media, Borja Servan Camas

LSU Doctoral Dissertations

The aim of this dissertation is to extend the lattice Boltzmann method (LBM) to cope with parameter heterogeneity and anisotropy in mass transport equations in porous media, as well as investigating the stability and accuracy. Although the LBM is a well known and effective numerical method to solve fluid flows, LBM has not been extensively applied to mass transport equations in porous medium flow yet, and only a few works can be found on improving LBM to cope with mass transport equations other than the diffusion and advection-diffusion equations. One of the reasons why LBM has not been extensively used …

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Dynamic Shear Bands In Metals Under High Strain Rates, Amin Hisham Almasri Jan 2008

Dynamic Shear Bands In Metals Under High Strain Rates, Amin Hisham Almasri

LSU Doctoral Dissertations

Adiabatic shear bands have been observed for a long time to occur under different conditions in many applications. Analysis of these localizations highly depends on the selection of the constitutive model. Hence, two constitutive models that take temperature and strain rate effect into account are proposed. The first model is a physically based model that depends on basic physical quantities, such as dislocation densities, Burgers vector, and activation energy. The second model is a simple empirical power model with a softening term. The empirical constitutive law is seen to be more successful in capturing the mechanical behavior of steel alloy …

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Synthesis And Surface Characterization Of Silica-Polypeptide Composite Particles, Erick Isael Soto-Cantu Jan 2008

Synthesis And Surface Characterization Of Silica-Polypeptide Composite Particles, Erick Isael Soto-Cantu

LSU Doctoral Dissertations

The synthesis and sequential surface characterization of silica-polypeptide composite particles is described. Nearly monodisperse colloidal silica cores were obtained by the alkaline hydrolysis of tetraethyl orthosilicate (TEOS). The hydrodynamic radius can be easily controlled in the range of ƒî 20-140 nm by the water/TEOS ratio in the starting reaction mixture. The surface of the synthesized silica cores was further passivated/functionalized (P/F) by a mixture of (3-aminopropyl) trimethoxysilane (APS) and methyl-trimethoxysilane (MTMS). The amino groups were quantified using UV-Vis spectrometry after reaction with ninhydrin. The use of zeta potential measurements of the P/F silica particles at low pH is presented as …

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Fast Marching Methods - Parallel Implementation And Analysis, Maria Cristina Tugurlan Jan 2008

Fast Marching Methods - Parallel Implementation And Analysis, Maria Cristina Tugurlan

LSU Doctoral Dissertations

Fast Marching represents a very efficient technique for solving front propagation problems, which can be formulated as partial differential equations with Dirichlet boundary conditions, called Eikonal equation: $F(x)|\nabla T(x)|=1$, for $x \in \Omega$ and $T(x)=0$ for $x \in \Gamma$, where $\Omega$ is a domain in $\mathbb{R}^n$, $\Gamma$ is the initial position of a curve evolving with normal velocity F>0. Fast Marching Methods are a necessary step in Level Set Methods, which are widely used today in scientific computing. The classical Fast Marching Methods, based on finite differences, are typically sequential. Parallelizing Fast Marching Methods is a step forward for …

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Incorporation Of Cα,Α-Disubstituted Amino Acids Into Model Peptide Systems: Conformational Analysis And Possible Applications As Therapeutic Agents, Marcus A. Etienne Jan 2008

Incorporation Of Cα,Α-Disubstituted Amino Acids Into Model Peptide Systems: Conformational Analysis And Possible Applications As Therapeutic Agents, Marcus A. Etienne

LSU Doctoral Dissertations

A diverse set of human diseases is associated with the misfolding of proteins into insoluble fibrillar structures that have predominantly β-sheet secondary structure. Thus it is imperative to elucidate the structural elements that contribute to β-sheet formation and stability. Peptides that autonomously form β-sheets are ideal models to study principles of protein folding and design. Gellman and coworkers first introduced an automonously folded β-hairpin (H-Arg-Tyr-Val-Glu-Val-Yyy-Xxx-Orn-Lys-Ile-Leu-Gln-NH2) that remained monomeric up to ~1 mM. Circular dichroism (CD) and nuclear magnetic resonance (NMR) analyses revealed that incorporation of non-stereogenic Aib-Xxx dipeptidyl sequences into i+1 and i+2 positions of a model peptide nucleates a …

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A Unified Methodology Of Maintenance Management For Repairable Systems Based On Optimal Stopping Theory, Hongye Wang Jan 2008

A Unified Methodology Of Maintenance Management For Repairable Systems Based On Optimal Stopping Theory, Hongye Wang

LSU Doctoral Dissertations

This dissertation focuses on the study of maintenance management for repairable systems based on optimal stopping theory. From reliability engineering’s point of view, all systems are subject to deterioration with age and usage. System deterioration can take various forms, including wear, fatigue, fracture, cracking, breaking, corrosion, erosion and instability, any of which may ultimately cause the system to fail to perform its required function. Consequently, controlling system deterioration through maintenance and thus controlling the risk of system failure becomes beneficial or even necessary. Decision makers constantly face two fundamental problems with respect to system maintenance. One is whether or when …

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