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Articles 2791 - 2820 of 3417

Full-Text Articles in Physical Sciences and Mathematics

Coastal Marsh Restoration Using Terraces: Effects On Waterbird Habitat In Louisiana's Chenier Plain, Jessica L. O'Connell Jan 2006

Coastal Marsh Restoration Using Terraces: Effects On Waterbird Habitat In Louisiana's Chenier Plain, Jessica L. O'Connell

LSU Master's Theses

Terracing is a novel technique used to combat coastal marsh loss in Louisiana and Texas. Terraces are assumed to slow marsh erosion, decrease pond depth, and encourage vegetation expansion. Terraced ponds have never been evaluated as habitat for waterbirds, which heavily depend on Louisiana�s coastal marshes. From April 2005 to April 2006, I monitored waterbird species richness and density through time to estimate effects that terracing has on habitat quality. Water quality (turbidity, salinity, conductivity, water temperature, and water depth) also was measured. Submerged aquatic vegetation (SAV) biomass and nekton density were measured from April 2005 to September 2005. I …

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The Feasibility Of Using Gps Technology For Continuous Time Studies Of Rubber-Tired Grapple Skidders, Robert Henry Dupre Jan 2006

The Feasibility Of Using Gps Technology For Continuous Time Studies Of Rubber-Tired Grapple Skidders, Robert Henry Dupre

LSU Master's Theses

Skidders are one of the most common timber harvesting machines used on mechanized logging operations in the southern United States and can represent the greatest single capital investment for a logging contractor. Time studies of skidders have been conducted on nearly every type of mechanized logging operation and are a key part of the productivity studies conducted on logging operation. GPS technologies have enabled researchers to move away from the typical manual time data collection for productivity studies and start conducting unattended time studies on skidding equipment. For this study a Trimble GeoXT with external antenna was installed in a …

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Evaluation Of Tcp Based Congestion Control Algorithms Over High-Speed Networks, Yaaser Ahmed Mohammed Jan 2006

Evaluation Of Tcp Based Congestion Control Algorithms Over High-Speed Networks, Yaaser Ahmed Mohammed

LSU Master's Theses

The Additive Increase Multiplicative Decrease (AIMD) algorithm of the Transport Control Protocol (TCP) had worked remarkably well over low speed networks and had guaranteed fairness to the users all over these years, but at present, the demands for transferring large quantities of data over very high-speed networks are increasing at a tremendous rate. Because of its AIMD algorithm to control its window growth function accompanied by a slow response function which is inadequate over high-speed links, TCP has been proven to underutilize the available network bandwidth and leave a considerable amount of unused bandwidth. To overcome this limitation of TCP, …

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Spatial Distribution Of Heavy Metals In Louisiana Sediments And Study Of Factors Impacting The Concentrations, Suniti Bhattarai Jan 2006

Spatial Distribution Of Heavy Metals In Louisiana Sediments And Study Of Factors Impacting The Concentrations, Suniti Bhattarai

LSU Master's Theses

To identify the sites with elevated metal concentrations and factors impacting the concentrations, we studied 128 observations on heavy metals collected from the four inch deep sediments in Louisiana lakes and rivers. Use of Fe as a normalizing factor to interpret the site of metal enrichment was justified based on its high correlation with other heavy metals. The regression coefficients of metal/Fe came out to be significant for all the metals in both level and log versions. For the metals, where prediction exceeded upper 95% confidence interval, we mapped the site with factors such as number of industries located within …

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Habitat Use By Nekton In A Saltmarsh Estuary Along A Stream-Order Gradient In Northeastern Barataria Bay, Louisiana, Pablo Granados-Dieseldorff Jan 2006

Habitat Use By Nekton In A Saltmarsh Estuary Along A Stream-Order Gradient In Northeastern Barataria Bay, Louisiana, Pablo Granados-Dieseldorff

LSU Master's Theses

Mesohaline estuarine regions in Louisiana play an important role in coastal ecosystems. To begin to understand how nektonic species and communities respond to environmental variables before habitat modification, I examined patterns of habitat use by fishes and decapod crustaceans in a seemingly pristine mesohaline system that drains into Bay Batiste, southeastern Louisiana. The study area was focused on a relatively unaltered core saltmarsh complex drained by intertidal and subtidal streams and it was representative of a larger surrounding system in terms of nekton community structure and associated environmental variables. Stratified monthly sampling (February – November 2004) along a stream-order gradient …

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Delineating Hurricane Vulnerable Populations In Orleans Parish, Louisiana, Stephanie Pedro Jan 2006

Delineating Hurricane Vulnerable Populations In Orleans Parish, Louisiana, Stephanie Pedro

LSU Master's Theses

Since settlement first began, equality issues between different social classes have been evident in the location of where residents settled in New Orleans. This research seeks to answer the question: What socioeconomic indicators are prevalent in the areas most-at-risk to flooding which could inhabit populations least able to evacuate? I will use Census 2000 block group data from the socioeconomic sample data (SF3) collected in 2000, along with other economic and GIS data from the New Orleans region to statistically represent the distribution of risk by selecting indicators predicted to be in flood zones from a classification tree analysis. Then, …

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Muscovite Pseudomorphs After Staurolite As A Record Of Fluid Infiltration During Prograde Metamorphism, Jennifer Kaye Whittington Jan 2006

Muscovite Pseudomorphs After Staurolite As A Record Of Fluid Infiltration During Prograde Metamorphism, Jennifer Kaye Whittington

LSU Master's Theses

Pressure-temperature conditions encountered by metamorphic rocks are often used to constrain tectonic environments of formation. Evidence of the prograde path during metamorphism is often obliterated by peak metamorphic conditions. However, pseudomorphs that form during prograde metamorphism may provide insights into heat and mass transport along this portion of the P-T-X-t path. Seventeen sillimanite zone samples, each containing 2-5 muscovite-rich pseudomorphs after staurolite, were investigated from pelitic schists of the Farmington Quadrangle, west-central Maine, USA. Pseudomorphs are easily recognized by an increase in average grain size (~cm) and change to randomly oriented muscovite-rich (~45-75%) modal mineralogy relative to the rock matrix …

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Effects Of Terraces On Submerged Aquatic Vegetation In Shallow Marsh Ponds In Coastal Southwest Louisiana, Christopher Dean Cannaday Jan 2006

Effects Of Terraces On Submerged Aquatic Vegetation In Shallow Marsh Ponds In Coastal Southwest Louisiana, Christopher Dean Cannaday

LSU Master's Theses

The wetlands of coastal Louisiana are disappearing at a rate of 65 to 80 km2yr-1. Most of the loss is the conversion of emergent marsh to shallow marsh ponds. Terracing is one restoration technique that has been used frequently in recent years. Terraces are small intertidal ridges built in shallow marsh ponds to reduce wave action. It is assumed that this will slow erosion of adjacent emergent marsh and increase Submerged Aquatic Vegetation (SAV) production, a key habitat component for many marsh fauna. Yet both relevant previous studies failed to show that terraces increased SAV abundance. …

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Dendrochronological Analysis Of Productivity And Hydrology In Two Louisiana Swamps, John Blake Amos Jan 2006

Dendrochronological Analysis Of Productivity And Hydrology In Two Louisiana Swamps, John Blake Amos

LSU Master's Theses

Modified river flows and land subsidence have subjected many coastal swamp forests in the delta of the Mississippi River to greatly altered flooding, sediment, and nutrient regimes. These areas have become inundated to greater depth, duration, and frequency and either are connected to the river and receive drastically increased sediment and nutrients (riverine swamps) or have become disconnected from riverine flooding (stagnant swamps) and receive little or no sediment and nutrient input. To better understand how these changes are affecting ecosystems, dendrochronological techniques for baldcypress (Taxodium distichum L. Rich.) were used at three sites in each of two contrasting swamps …

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Infrared Laser Desorption/Ionization Mass Spectrometry: Fundamental And Applications, Mark Little Jan 2006

Infrared Laser Desorption/Ionization Mass Spectrometry: Fundamental And Applications, Mark Little

LSU Doctoral Dissertations

This dissertation on infrared laser desorption/ionization mass spectrometry encompasses fundamental studies of the desorption/ionization process and direct-from-gel laser desorption/ionization applications. Understanding of the fundamentals behind desorption and ionization can lead to improvements in the technique and to new applications. Experiments aimed at advancing this goal are wavelength studies and two-laser infrared/ultraviolet matrix-assisted laser desorption/ionization experiments. The direct-from-gel laser desorption/ionization application in which infrared laser desorption/ionization of analytes directly ionized after gel electrophoretic separation will also be presented. Protein and peptide standards were used as test analytes and the infrared lasers used were a 10.6 micrometers carbon-dioxide laser and a mid-IR …

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Effects Of Diesel-Fuel And Copper Contaminants On Benthic Microalgae, Soraya Silva Jan 2006

Effects Of Diesel-Fuel And Copper Contaminants On Benthic Microalgae, Soraya Silva

LSU Doctoral Dissertations

Salt marshes are dynamic, highly productive habitats and serve as nursery grounds for many commercially and economically important species. Benthic microalgae (BMA) are considered an important food source for benthos and provide the principal source of nutrition that fuels secondary production. Estuarine sediments around the world are a repository for many contaminants from anthropogenic sources. In particular, hydrocarbons and metals are ubiquitous contaminants in coastal systems. The primary goal of this study was to study the effects of diesel fuel and copper, alone and in combination, on the BMA assemblage from a coastal salt marsh. To achieve this objective, salt …

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Factors Influencing The Participation In Environmental Stewardship Programs: A Case Study Of The Agricultural And Forestry Sectors In Louisiana, Carrie Castille Mendoza Jan 2006

Factors Influencing The Participation In Environmental Stewardship Programs: A Case Study Of The Agricultural And Forestry Sectors In Louisiana, Carrie Castille Mendoza

LSU Doctoral Dissertations

Considerable research has been conducted to evaluate the adoption of agricultural best management practices and their overall impact on improving environmental quality. However, limited studies have been conducted to evaluate the behavioral factors that influence the adoption of these practices in the context of educational programs The goal of this study is to determine the factors that influence farmer conservation behavior that might lead to an increased probability of improving agriculture and forestry watersheds. A conceptual model was developed to identify the: 1) identify landowner participation in watershed conservation projects, and 2) determine the factors influencing agriculture and forestry landowners …

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Synthesis, Crystal Growth, Magnetic And Transport Properties Of Ln-M-X (Ln=Lanthanide, M=Transition Metal, X=In, Ga) Compounds, Willa Maria Williams Jan 2006

Synthesis, Crystal Growth, Magnetic And Transport Properties Of Ln-M-X (Ln=Lanthanide, M=Transition Metal, X=In, Ga) Compounds, Willa Maria Williams

LSU Doctoral Dissertations

ABSTRACT This dissertation focuses on the structural stability, magnetic and transport properties of ternary lanthanide compounds grown using indium and gallium flux. Single crystals of TbRhIn5 were synthesized using indium flux. TbRhIn5 is isostructural to the well known LnnMIn3n+2 (n = 1, 2, ∞; Ln = La, Ce; M = Rh, Ir) and adopts the HoCoGa5 structure type and crystallizes in the space group P4/mmm, Z = 1. Lattice parameters are a = 4.6000(6) Å and c = 7.4370(11) Å, V = 157.29(6) Å3. A sharp antiferromagnetic transition is observed at TN = 48 K for TbRhIn5. Single crystals of …

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Self-Assembly And Its Inhibition In Bolaform Amphiphilic Dendrimers, Jirun Sun Jan 2006

Self-Assembly And Its Inhibition In Bolaform Amphiphilic Dendrimers, Jirun Sun

LSU Doctoral Dissertations

Self-assembly is scientifically interesting, technologically important, and sometimes life-threatening. A striking example: Alzheimer’s disease is caused by the self-assembly of the â-amyloid fragment of amyloid precursor protein. Such natural amphiphiles normally are very expensive and complicated to isolate. Synthetic mimics that are much cheaper and easier to prepare can facilitate the development of efficient characterization methods, even as they suggest new materials science applications. Two-directional arborols are synthetic bolaform amphiphilic dendrimers. They dissolve in hot water and form reversible gels at room temperature. Bundles of fibrils, which are made by self-assembly of arborols, are found in the gels. The properties …

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Ab Initio Molecular Dynamics Simulations Of Methylaluminoxane (Mao) Synthesis By Hydrolysis Of Trimethylaluminum, Lacramioara Negureanu Jan 2006

Ab Initio Molecular Dynamics Simulations Of Methylaluminoxane (Mao) Synthesis By Hydrolysis Of Trimethylaluminum, Lacramioara Negureanu

LSU Doctoral Dissertations

MAO is the co-catalyst in the metallocene catalytic systems, which are widely used in single site olefin polymerization due to their high stereoselectivity. To date, the precise structure of MAO, the particular compound or compounds catalytically active in MAO, have eluded researchers. MAO, a white amorphous powder, is not a good sample for a direct spectroscopic characterization, and its NMR spectra are broad and almost featureless. Many structural models have been proposed but none are generally accepted. In the first part of this work the MAO formation mechanism was addressed. Molecular dynamics simulations at MP2 configuration interaction theory level have …

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Structural And Forecasting Softwood Lumber Models With A Time Series Approach, Nianfu Song Jan 2006

Structural And Forecasting Softwood Lumber Models With A Time Series Approach, Nianfu Song

LSU Doctoral Dissertations

The development of cointegration theories and the presence of nonstationarity in time series raised serious concerns about possible spurious estimations in forest products models. Based on the results of Hsiao (1997a, 1997b), all the virtues of two-stage least square (2SLS) hold if there are sufficient cointegration relations. Stationary null and nonstationary null unit root tests and monthly seasonal unit root tests were applied to the time series used in this dissertation. Cointegration tests with exogenous variables were performed to justify the 2SLS. A regional error correction model (ECM) with four regional lumber supply and demand equations and a U.S.-Canada supply …

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Effects Of An External Field And Dissipation On Decoherence, Jian Zuo Jan 2006

Effects Of An External Field And Dissipation On Decoherence, Jian Zuo

LSU Doctoral Dissertations

Decoherence is the suppression of the interference of quantum states. It plays important roles in the study of the quantum-classical transition. It is also the major obstacle in the implementation of various schemes of quantum computers. Decoherence can be affected by many factors. The interactions between quantum systems of interest and dissipative environments cause the extensively studied environment-induced-decoherence. Decoherence can also occur as the result of a temperature effect. A recent experiment investigated the engineering of decoherence, which involves applying an external field to the quantum system. In this thesis, we study the effect of an external field on decoherence …

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Nutrient Constraints On Plant Community Production And Organic Matter Accumulation Of Subtropical Floating Marshes, Guerry O., Jr. Holm Jr. Jan 2006

Nutrient Constraints On Plant Community Production And Organic Matter Accumulation Of Subtropical Floating Marshes, Guerry O., Jr. Holm Jr.

LSU Doctoral Dissertations

In the cycle of delta growth and decay, peat-forming wetlands span a time and space continuum. Later in the delta cycle, freshwater floating marshes become increasingly removed from external sediment subsidy and internal nutrient cycling controls plant productivity and organic matter accumulation. An interesting question is whether increased external nutrient loading can affect the basic processes that lead to peat formation—plant production and organic matter decomposition. I conducted several field studies to understand whether belowground organic matter accumulation and decomposition were affected with increased nutrient exposure; in addition, the plant community was monitored over three years. A laboratory soil respiration …

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Modeling The Effects Of Endocrine Disrupting Chemicals On Atlantic Croaker: Understanding Biomarkers And Predicting Population Responses, Cheryl Anne Murphy Jan 2006

Modeling The Effects Of Endocrine Disrupting Chemicals On Atlantic Croaker: Understanding Biomarkers And Predicting Population Responses, Cheryl Anne Murphy

LSU Doctoral Dissertations

A number of environmental stressors have been shown to interfere with reproductive and behavioral processes of fish by interfering with endocrine function. Most biomarkers of endocrine disturbance tend to be static measurements from dynamic systems making them difficult to evaluate within the context of an individual, or subtle effects that do not relate well to endpoints of ecological significance. I present an approach that uses a series of models, based on Atlantic croaker, to extrapolate laboratory results to indicators of individual and population health. First, I created a physiologically based model that simulates vitellogenesis in a female fish. The model …

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Direct Detection Of Homocysteine And Syntheses Of Lanthanide Complexes As Biosensors, Weihua Wang Jan 2006

Direct Detection Of Homocysteine And Syntheses Of Lanthanide Complexes As Biosensors, Weihua Wang

LSU Doctoral Dissertations

At elevated levels, homocysteine (Hcy) is a risk factor for cardiovascular diseases and Alzheimer’s disease. It’s also implicated in a number of other diseases such as neural tube defects, pregnancy complications, and renal failures. The monitoring of Hcy levels in plasma is of current concern. To date, the biochemical mechanism by which Hcy is involved in disease states is unclear. Herein, we describe highly selective colorimetric methods for the direct determination of Hcy. Inexpensive, commercially available materials are reported. The results show potential application for the detection of Hcy in human blood plasma. Additionally, new HPLC postcolumn detection methods for …

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Applications Of Titanium-Mediated Reductive Coupling And Cyclocarbonylation Reactions Toward Natural Product Synthesis, Maria A. Appeaning Jan 2006

Applications Of Titanium-Mediated Reductive Coupling And Cyclocarbonylation Reactions Toward Natural Product Synthesis, Maria A. Appeaning

LSU Doctoral Dissertations

Previous work in our laboratory has demonstrated not only a synthetic value of tandem reductive cyclization - carbonylation reactions in the preparation of complex molecules but also the interesting stereoselectivity observed therein. The first part of this work employs the titanium-mediated cyclocarbonylation of tethered dienals for the synthesis of prostaglandin analogues, in particular PGF2α and methyl jasmonate. Based on this hetero Pauson-Khand strategy, we have established an efficient racemic route to both the prostaglandin and the methyl jasmonate core skeletons. Moderate to excellent selectivities with regard to the hetero Pauson-Khand reaction were observed in both cases. The second part …

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On Moment Conditions For The Girsanov Theorem, See Keong Lee Jan 2006

On Moment Conditions For The Girsanov Theorem, See Keong Lee

LSU Doctoral Dissertations

In this dissertation, the well-known Girsanov Theorem will be proved under a set of moment conditions on exponential processes. Our conditions are motivated by the desire to avoid using the local martingale theory in the proof of the Girsanov Theorem. Namely, we will only use the martingale theory to prove the Girsanov Theorem. Many sufficient conditions for the validity of the Girsanov Theorem have been found since the publication of the result by Girsanov in 1960. We will compare our conditions with some of these conditions. As an application of the Girsanov Theorem, we will show the nonexistence of an …

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Two-Dimensional And High-Throughput Electrophoretic Separation Of Proteins Using Polymeric Microchips, Hamed Shadpour Jan 2006

Two-Dimensional And High-Throughput Electrophoretic Separation Of Proteins Using Polymeric Microchips, Hamed Shadpour

LSU Doctoral Dissertations

A major task in proteomics is to identify proteins from a biological sample using two-dimensional (2-D) separation prior to mass spectrometry of peptides generated via proteolytic digestion of the proteins. For 2-D separations, microfluidic devices are superior to bench top and capillary-based systems since they potentially provide higher separation efficiencies due to the minimal dead volumes produced during peak transfer between the two separation dimensions. In addition, fast separations can be envisioned because the column lengths are typically shorter in microfluidic platforms without scarifying peak capacity. High-throughput capabilities are extremely desirable for many types of bio-analytical analyses, such as understanding …

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Magnetic, Thermodynamic And Transport Properties Of The Magnetic Semiconductor Fe₁₋Xcoxs₂ And Superconducting Lasb₂, Song Guo Jan 2006

Magnetic, Thermodynamic And Transport Properties Of The Magnetic Semiconductor Fe₁₋Xcoxs₂ And Superconducting Lasb₂, Song Guo

LSU Doctoral Dissertations

In recent years magnetic semiconductors have attracted a great deal of attention because it is thought that they can be used to generate spin polarized current in spintronics, an emerging field where the spin degree of freedom of charge carriers is utilized in microelectronic devices. In this dissertation work, we investigate the magnetic, thermodynamic, and transport properties of the magnetic semiconductor Fe1-XCoxS2 for x less than 0.14, the doping range where Insulator-to-Metal and paramagnetic-to-ferromagnetic transitions occur. We discovered that the Kondo effect is an important ingredient in the paramagnetic region of magnetic semiconductor Fe1-X …

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Crystal Growth And The Search For Highly Correlated Ternary Intermetallic Antimonides And Stannides, Evan Lyle Thomas Jan 2006

Crystal Growth And The Search For Highly Correlated Ternary Intermetallic Antimonides And Stannides, Evan Lyle Thomas

LSU Doctoral Dissertations

This dissertation describes the crystal growth, chemical structures, and efforts made towards the understanding of the physical properties of novel ternary rare-earth intermetallics, which may display signature behavior such as superconductivity, heavy fermion behavior, intermediate valence, and/or large magnetoresistance. To address the problem of correlating these characteristics with structural features, several ternary antimony- and tin-containing phases, Ln-T-X (Ln = lanthanide; T = Co, Ni, Pd; X = Sn, Sb), have been synthesized in single crystalline form by metallic flux-growth methods and characterized by X-ray diffraction. The antimonide compounds LnNi1-xSb2 (Ln = Y, Gd-Tb, Er, Yb), alpha, beta-LnNiSb3 (Ln = La, …

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Structural Characterization Of Poly(Heterocycles) Formed Using Oxidative Methods, Rebecca Marie Brauch Jan 2006

Structural Characterization Of Poly(Heterocycles) Formed Using Oxidative Methods, Rebecca Marie Brauch

LSU Doctoral Dissertations

This research focused on elucidation of structural information for conducting polymer systems using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The structure of conducting polymer systems has been found to directly influence their physical properties. Poly(pyrrole) and poly(thiophene) are two of the most widely studied conducting polymers due to their high electrical conductivity, stability in the doped state, low toxicity, and current/potential applications. The purpose of this research was to apply MALDI-TOF MS to heterocyclic conducting polymers, specifically those of pyrrole and thiophene, to investigate structural properties of these polymers, with the specific aim of determining end group and …

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Numerical Techniques For Fresnel Diffraction In Computational Holography, Richard Patrick Muffoletto Jan 2006

Numerical Techniques For Fresnel Diffraction In Computational Holography, Richard Patrick Muffoletto

LSU Doctoral Dissertations

Optical holography can produce very realistic virtual images due to its capability to properly convey the depth cues that we use to interpret three-dimensional objects. Computational holography is the use of digital representations plus computational methods to carry out the holographic operations of construction and reconstruction. The large computational requirements of holographic simulations prohibit present-day existence of real-time holographic displays comparable in size to traditional two-dimensional displays. Fourier-based approaches to calculate the Fresnel diffraction of light provide one of the most efficient algorithms for holographic computations because this permits the use of the fast Fourier transform (FFT). The limitations on …

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River, Tidal And Wind Interactions In A Deltaic Estuarine System, Gregg Snedden Jan 2006

River, Tidal And Wind Interactions In A Deltaic Estuarine System, Gregg Snedden

LSU Doctoral Dissertations

The balance between river and marine influences is important in governing landscape sustainability in river deltas. River- and atmospherically driven sea level variability, sediment loading, and estuary-ocean exchange in the Mississippi River delta are examined in this study. Subtidal estuarine sea level variability in the Breton Sound estuary was driven by a combination of remote atmospheric forcing outside the estuary over the continental shelf and controlled river inputs through a gated diversion structure at the estuary head. The highly-frictional deltaic landscape acted as a low-pass filter to coastal fluctuations near the estuary mouth. When substantial quantities river water were discharged …

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Synthesis, Characterization And Properties Of Cooper(Ii) Beta-Diketonate Macrocycles, Sylvester Burton Jan 2006

Synthesis, Characterization And Properties Of Cooper(Ii) Beta-Diketonate Macrocycles, Sylvester Burton

LSU Doctoral Dissertations

This dissertation deals with the synthesis and properties of multidentate β-diketone ligands and their transition-metal complexes. (1) We prepared two bis(β-diketones), C1BAH2 and p-XBAH2 (see sketch below), determined their crystal structures, and studied their reactions with copper(II). We envisioned that they would form macrocyclic complexes with 3-6 metal atoms. In both cases, although the initial products are soluble, as expected for the desired molecular products, we were unable to isolate well-behaved molecular solids. In the case of C1BAH2, this may be because the cyclic product requires an unusual combination of conformations of …

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An Inverse Homogenization Design Method For Stress Control In Composites, Michael Stuebner Jan 2006

An Inverse Homogenization Design Method For Stress Control In Composites, Michael Stuebner

LSU Doctoral Dissertations

This thesis addresses the problem of optimal design of microstructure in composite materials. The work involves new developments in homogenization theory and numerical analysis. A computational design method for grading the microstructure in composite materials for the control of local stress in the vicinity of stress concentrations is developed. The method is based upon new rigorous multiscale stress criteria connecting the macroscopic or homogenized stress to local stress fluctuations at the scale of the microstructure. These methods are applied to three different types of design problems. The first treats the problem of optimal distribution of fibers with circular cross section …

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