Digital Commons Network^™

M1 Strength Distributions In Deformed Nuclei., Thomas Georg Beuschel

LSU Historical Dissertations and Theses

The Elliott SU(3) Model, extended via pseudo-spin for heavy nuclei, is used to study low-lying magnetic dipole excitations in deformed nuclei which axe known as "scissors" modes. Proton and neutron degrees of freedom are handled explicitly and a system Hamiltonian that preserves SU(3) symmetry and one that includes single particle energies as well as quadrupole-quadrupole and pairing two-body interactions are considered. Starting from a basic nuclear Hamiltonian that preserves SU(3) symmetry, a microscopic interpretation of the "scissors" mode of the Two Rotor Model is realized through a linear mapping between invariants of the rotor group and SU(3). The model allows …

Internal Defect Detection In Hardwood Logs With Fast Magnetic Resonance Imaging., Eyler Robert Coates Jr

LSU Historical Dissertations and Theses

Identification of defects such as knots in logs before the cutting operation would allow lumber mills to maximize the value of lumber from each log. This dissertation presented images obtained from scanning an oak log with magnetic resonance imaging (MRI). The unique characteristics of MRI images of hardwood logs were noted and were used to derive a quick algorithm to isolate defects. Defect regions had some pixels that varied considerably in intensity from their neighborhood, providing a seed for initiating the defect region. There was an overlap between the pixel gray level of the defects and clear wood. Therefore, traditional …

Pressure-Induced Changes In Structural And Mechanical Properties Of Gallium Arsenide And Nanophase Silicon Carbide Using Parallel Molecular Dynamics Simulations., Alok Chatterjee

LSU Historical Dissertations and Theses

Large-scale parallel molecular-dynamics (MD) simulations are performed to investigate properties and processes in nanophase silicon carbide (n-SiC) and gallium arsenide (GaAs) under pressure. These simulations involve 10 6 atoms interacting via realistic interatomic potentials. Structure and sintering of crystalline n-SiC are also investigated with neutron scattering experiments performed at the Intense Pulsed Neutron Source Division (IPNS), Argonne National Laboratory. Both MD simulations and neutron scattering experiments indicate the onset of sintering around 1500K. During sintering, the pores shrink in size while maintaining their morphology: Their fractal dimension remains ∼2.4 and their surface roughness exponent is ∼0.45. The pair distribution functions …

Nanostructure Modeling In Oxide Ceramics Using Large Scale Parallel Molecular Dynamics Simulations., Timothy J. Campbell

LSU Historical Dissertations and Theses

The purpose of this dissertation is to investigate the properties and processes in nanostructured oxide ceramics using molecular-dynamics (MD) simulations. These simulations are based on realistic interatomic potentials and require scalable and portable multiresolution algorithms implemented on parallel computers. The dynamics of oxidation of aluminum nanoclusters is studied with a MD scheme that can simultaneously treat metallic and oxide systems. Dynamic charge transfer between anions and cations which gives rise to a compute-intensive Coulomb interaction, is treated by the O(N) Fast Multipole Method. Structural and dynamical correlations and local stresses reveal significant charge transfer and stress variations which cause rapid …

Spatial Variability Of Coastal Organic Soil Characteristics., L. Cecil Dharmasri

LSU Historical Dissertations and Theses

This dissertation is a part of the Louisiana NASA/EPSCoR (Experimental Program to Stimulate Competitive Research) global change research, which studied the fate of carbon and sediments within the Barataria Bay Basin, Louisiana. It studied water composition to assess seawater influence within the marsh. Ion exchange resin strips were used to study the effect of salinity and Chloride (Cl) on sulfate (SO4) reduction and their potential for water and soil analysis. Chloride dominated the water system and the Cl/SO 4 ratio can be used to assess the seawater influence. Resin extractable sulfur (S) predicted non-pyritic S fraction for the marsh soils. …

Ultrafast Studies Of Reaction Dynamics., Zhenguo Feng

LSU Historical Dissertations and Theses

The long range goal of this research is to understand the role of the solvent in condensed phase reactions. In the gas phase, great strides have been made towards understanding chemical reactivity at the level of individual quantum states. Liquid state reactions are not as well understood due to complicated many-body interactions with the solvent. Our approach has been to study simple reactions in solvents near their critical state. Here a small change in pressure, at constant temperature, allows a continuous change in solvent bulk density and viscosity, from near-liquid to gas-like properties. In this way reactions can be studied …

Determination Of Optimal Composition Of Stabilized Phosphogypsum Composites For Saltwater Application., Tingzong Guo

LSU Historical Dissertations and Theses

Phosphogypsum (CaSO4 ˙ 2H2O, PG), a solid by-product of phosphoric acid production, has been classified as a "Technologically Enhanced Natural Radioactive Material" (TENR), because it contains radionuclides (eg., radium 226) and some trace toxic metals in concentrations, which may pose a potential hazard to human health and the environment. The current regulated disposal method for PG is on-site stockpiling, which has created a serious environmental management problem. An appealing solution to the problem is the use of stabilized PG for aquatic enhancement activities. This solution can eliminate the airborne vector of transmission for radon 222 and therefore may provide a …

Computer-Assisted Instruction: Enhancements For Language-Learning Applications., William Lawrence Harrell Jr

LSU Historical Dissertations and Theses

Presently, computer-assisted instruction is in use in many educational venues. Unfortunately, the application of computer-assisted language learning at a distance has virtually been ignored. This is an opportunity that needs to be explored. In order to do so, a number of considerations must be attended to. First, effective monitor display design is critical for the optimal presentation of distance learning material. Second, gender and equity factors that impact computer use must be understood to minimize the detrimental effects they might have on computer-assisted distance learning. Third, the needs of students involved with the particularly-demanding application of distance learning principles of …

The Conversion Of Light Amines Over Copper-Containing Zeolites., Trent Francis Guidry

LSU Historical Dissertations and Theses

Copper-containing zeolites have been prepared by vapor, aqueous, and solid-state ion-exchange, characterized, and investigated for the conversion of light amines. A copper-containing zeolite was synthesized by vapor ion-exchange in this study by a method that does not appear to have been previously reported. This material was prepared by reaction of the acidic zeolite with CuCl vapor, followed by oxidation of the Cu+ ions to copper oxonium. ions which are converted to copper hydroxyl dimers on exposure to air. The copper hydroxyl dimer exchanged zeolite is stable in air and can be converted back to a highly exchanged Cu+ zeolite by …

The Effects Of Autocorrelation In The Estimation Of Process Capability Indices., Lawrence Lee Magee

LSU Historical Dissertations and Theses

The current popularity of the process capability index, a measure of a supplier's ability to meet the product specifications demanded by a customer, has become a matter of some controversy. While admitting the validity of much existing criticism, this research demonstrates that sample estimation of the triple index (Cpl, Cp, Cpu), a variant of the widely used index pair (Cp, Cpk), is equivalent to estimation of the natural parameters (mu, sigma) whenever the measured process characteristic X has an unconditional (marginal) normal probability density function. This includes processes which obey the strictly stationary, normal ARMA( p, q) model. By this …

Nonlinear Tracking Control Using A Robust Differential-Algebraic Approach., Michael Christopher Mickle

LSU Historical Dissertations and Theses

This dissertation presents the development and application of an inherently robust nonlinear trajectory tracking control design methodology which is based on linearization along a nominal trajectory. The problem of trajectory tracking is reduced to two separate control problems. The first is to compute the nominal control signal that is needed to place a nonlinear system on a desired trajectory. The second problem is one of stabilizing the nominal trajectory. The primary development of this work is the development of practical methods for designing error regulators for Linear Time Varying systems, which allows for the application of trajectory linearization to time …

Thermomechanical Characterization Of Heat-Activated Coupling For Advanced Composite Piping Systems., Patrick Fitzgerald Mensah

LSU Historical Dissertations and Theses

A new technology for joining advanced composite piping systems, based on heat-activated coupling (HAC) of a thermosetting pre-impregnated (prepreg) fiber reinforced material has been advanced. The successful design of a heat-activated coupled joint depends on achieving the following requirements: (1) uniformly cured prepreg bonded to the surfaces of coupled pipe; and (2) minimal residual thermal stress as a result of the curing process. In order to address the above concerns, thermal characterization of the uncured and cured prepreg used was undertaken in order to establish prerequisite chemical kinetics parameters and material property data required for the curing process models and …

Characterization And Analysis Of The Superabrasive Diamond Blade Sawing Process., Harlan Dwayne Jerro

LSU Historical Dissertations and Theses

Diamond-impregnated segmented circular blade sawing is one of the most effective, versatile, and extensively used methods of processing rock and other hard materials, such as granite, marble, concrete and asphalt. For many years, it has been known that chip thickness is one of the most significant parameters in the understanding of the sawing process, and other variables such as force and power have been correlated with it. In this work, the material chipping geometries have been mathematically defined and derived through kinematics analysis. From these chipping geometries, chip area and thickness relations have been obtained. A relation for the mean …

Modeling And Optimal Design Of Spiral-Wound Membrane Systems For Gas Separations., Runhong Qi

LSU Historical Dissertations and Theses

Membrane system economics can be significantly affected by process modeling and design. Available spiral-wound permeator models are difficult to use for process design because of their mathematical complexity and high computational demands. Existing sequential design methods yield suboptimal flowsheets when multiple permeation stages are required. In this dissertation, more effective modeling and design techniques for spiral-wound systems separating binary and multicomponent gas mixtures are developed. An approximate modeling approach based on the assumption that the residue flow rate is constant in the direction of bulk permeate flow is proposed. This assumption allows a significant simplification of basic transport models which …

On The Value Functions Of Some Singular Optimal Control Problems., Jesus Alberto Pascal

LSU Historical Dissertations and Theses

Infinite horizon singular optimal control problems with control taking values in a closed cone U in Rn lead to a dynamic programming equation of the form: maxF2x,v, v',v'' ,F1x,v,v' =0, forall x∈Q, where Q , the state space of the control problem, is some nonempty connected open subset of Rn , and F1, F2 are continuous real-valued functions on QxR2 and QxR3 respectively, with the coercivity assumption for F 2, that is, the function r&rarrr;F2x,u,p,r is nonincreasing on R . A major concern is to determine how smooth the value function v is across the free boundary of the problem. …

Assessing The Reuse Potential Of Objects., Maria Lorna Reyes

LSU Historical Dissertations and Theses

In this research, we investigate whether reusable classes can be characterized by object-oriented (OO) software metrics. Three class-level reuse measures for the OO paradigm are defined: inheritance-based reuse, inter-application reuse by extension, and inter-application reuse as a server. Using data from a software company, we collected metrics on Smalltalk classes. Among the 20 metrics collected are cyclomatic complexity, Lorenz complexity, lines of code, class coupling, reuse ratio, specialization ratio and number of direct subclasses. We used stepwise regression to derive prediction models incorporating the 20 metrics as the independent variables and the reuse measures, applied separately, as the dependent variable. …

Prevention Of Hydrolytic And Oxidative Rancidity And Nutrient Losses In Rice Bran During Storage., Fatemeh Malekian Ramezanzadeh

LSU Historical Dissertations and Theses

Freshly milled raw rice bran was stabilized with microwave heat for 3 min. Half of raw and treated bran were packed in Ziplock(c) bags and the other half vacuum packed. Half of the samples were stored at 4--5°C and the other half at 25°C for 16 weeks. The free fatty acid (FFA) content increased rapidly in raw rice bran samples vacuum packed and samples packed in Ziplock(c) bags store at 25°C from an initial amount of 2.5% to 54.3% and 48.1%, respectively. FFA level increased significantly in raw samples vacuum packed and packed in Ziplock (c) bags stored 4--5°C from …

Bioremediation Of Petroleum Hydrocarbons In Louisiana's Saltwater Marshes: Sediment Oxygen Demand Model., Won Sik Shin

LSU Historical Dissertations and Theses

Laboratory core studies were conducted to determine sediment oxygen demand (SOD) in petroleum hydrocarbon contaminated salt marshes. Natural degradation processes in salt marshes such as aerobic respiration, nitrification and sulfate reduction were investigated to quantify SOD. Oxygen demand in oiled/fertilized cores was greater than control and fertilized cores due to increased oxygen consumption by oil degradation and oxidation of reduced chemicals; sulfide and ammonium. SOD under non-flooded condition was greater than flooded condition due to an increased area of oxic-anoxic interface during air exposure. This may indicate that significant biodegradation of crude oil only occurs when the surface of the …

Facilitating Knowledge Integration And Flexibility: The Effects Of Reflection And Exposure To Alternative Models., Lewis Garnet Roussel Jr

LSU Historical Dissertations and Theses

Three experiments investigated the effect of various kinds of reflection (within-task and post-task reflection) on learning a process control task. Also, two ways of providing learners with alternative ideas about task behavior, exposure to other's ideas and providing hints for task solution, were examined. The task involved a simulated "sugar production factory" in which the learners sought to control sugar production by manipulating workforce size. It was predicted that combining within-task reflection with exposure to alternative task ideas would lead to superior task performance through integration of experiential and reflective knowledge. Contrary to the prediction, within-task reflection consistently interfered with …

Significance Of The Effect Of Nitrogen Application On The Engineered Bioremediation Of Crude Oil In A Salt Marsh., Paul Timothy Tate

LSU Historical Dissertations and Theses

The biodegradation of the crude oil in a salt marsh was monitored by tracking the decline of the ratio of various components in the crude oil to a stable marker, hopane. In studies of mesocosms, addition of nitrogen as ammonium nitrate resulted in more rapid biodegradation of the oil at 0.10 significance. In field plots, addition of nitrogen was found to not significantly increase the rate of oil degradation over the rate in the control plots. The degradation of the oil is best described by a first order decay equation. The kinetic rate parameter k was 0.0054/day in the control …

The Effect Of Participation In The Occupational Safety And Health Administration's Voluntary Protection Programs On Injury/Illness Rates., Linda Diane Weems

LSU Historical Dissertations and Theses

The purpose of this study was to determine the effect participation in the Occupational Safety and Health Administration's (OSHA) Voluntary Protection Programs (VPP) has on injury/illness rates (IIR). Data was obtained from OSHA's Office of Cooperative Programs for the companies participating in the VPP for the years 1983 through 1997. This data was summarized and analyzed to satisfy this study's objectives. Objective 1 was to describe and compare the companies participating in OSHA's VPP and their IIR with the average IIR reported by the Bureau of Labor Statistics (BLS) for the industries for each year of the program's existence from …

Stress And Strength Of Laminated Composite Containing A Circular Hole., Yi Zhao

LSU Historical Dissertations and Theses

This dissertation is to study the stress and strength of a finite laminated plate containing a circular hole subjected to tension. Efforts were made in three aspects: theoretical modeling, computer simulation using finite element method, and experimental evaluation using unidirectional and crossply Scotchply laminates. The stress concentration factor, normal stress distribution and tensile strength of laminates with various hole sizes and gage lengths were investigated. Theoretically, two models were proposed to describe the normal stress distribution of a laminate with finite width and finite length. By defining a width correction function and a size correction function, the normal stress in …

Applications Of Band Ratioing At Fort Irwin, California., Alexander Wright Taylor

LSU Historical Dissertations and Theses

This dissertation describes the results of two projects that demonstrate the power of band ratioing of remote sensing data. The first method, Band Ratio Differencing (BRD), challenges the more traditional techniques for detecting environmental disturbance of the surface in and terrains. These traditional techniques are inadequate because they cannot identify the nature of the change (physical, chemical, biological) or the processes (natural, anthropogenic) involved in causing the change. In contrast, BRD of Landsat TM data has the advantage of providing information about changes in the composition of alluvial surfaces. These compositional changes, when combined with empirical field data provides insight …

First-Principles Determination Of Elastic Properties Of Casio3 Perovskite At Lower Mantle Pressures, Bijaya B. Karki, Jason Crain

Faculty Publications

We investigate the equation of state and elasticity of cubic CaSiO perovskite up to 140 GPa using the plane wave pseudopotential method within the local density approximation. The calculated equation of state parameters of the cubic phase are in excellent agreement with those from recent quasi-hydrostatic compression data and from all-electron linearized augmented plane wave calculations. We determine the elastic constant tensor of the mineral from the calculated stress-strain relations. The bulk modulus of CaSiO perovskite is similar to that of MgSiO perovskite, however, its shear modulus is much higher at pressures corresponding to the lower mantle. This suggests that …

Compilation Techniques For Out-Of-Core Parallel Computations, M. Kandemir, A. Choudhary, J. Ramanujam, R. Bordawekar

Faculty Publications

The difficulty of handling out-of-core data limits the performance of supercomputers as well as the potential of the parallel machines. Since writing an efficient out-of-core version of a program is a difficult task and virtual memory systems do not perform well on scientific computations, we believe that there is a clear need for compiler directed explicit I/O approach for out-of-core computations. In this paper, we first present an out-of-core compilation strategy based on a disk storage abstraction. Then, we offer a compiler algorithm to optimize locality of disk accesses in out-of-core codes by choosing a good combination of file layouts …

A Palynological Study Of Two Upland Bogs In The Gulf Coastal Plain, Alabama And Mississippi, Linda C. Pace

LSU Historical Dissertations and Theses

Fewer Quaternary palynological studies have been conducted in the Gulf Coastal Plain of the southeastern United States than In the northern United States and Canada, resulting in major gaps in the pollen record of this region. The existing studies display discrepancies in the chronology of the pine rise, appearance of the modem climatic regime and vegetation, and timing of the Hypsithermal. In order to fill a gap in the paleoecological data network of the Gulf Coastal Plain, pollen analysis, charcoal analysis, and sediment stratigraphic techniques were used to reconstruct the last 6500 years of Sweetbay Bog, Mississippi, and Minamac Bog, …

Of Rectangles And Centuries. A History Of The Use Of A Garden Pattern From Romanesque Europe To Nineteenth-Century New Orleans, David Dwayne Lewis

LSU Historical Dissertations and Theses

Settlers of New Orleans brought with them ideas of gardens that influenced the way they shaped gardens in the colony. Although the influence of those ideas has been acknowledged in studies of New Orleans gardens, specific connections between the ideas and gardens in New Orleans have not been made. To illuminate some of those connections, this study focuses on one garden pattern — a composition of long, rectangular planting beds -- that is common to at least fifty gardens in New Orleans and to European gardens dating from the ninth century. A developmental history that chronicles the use of the …

Effect Of Application Frequency On The Fate Of Azinphosmethyl In A Sugercane Field (Bulletin #863), H. M. Selim, R. L. Bengtson, L. M. Southwick, R. Ricaud, H. P. Schexnayder

LSU AgCenter Bulletins

Reducing the amounts of dissolved substances in surface and ground water is of major concern nationally and within the agricultural community. The primary focus of this study was to investigate the fate of azinphosmethyl (Guthion®) in sugarcane canopy, soil and runoff water.

F97rs Sgb No. 16 (Mini-Baja), Edel

Student Senate Enrolled Legislation

A BILL

To appropriate One Thousand Dollars ($1000.00) to the LSU Mini-Baja Team.

Prediction Of Timing Signals In Financial Series Using Neural Networks, Asheesh Mehta

LSU Historical Dissertations and Theses

The stock markets represent a complex system of inter-related factors that are difficult to model using conventional statistical techniques. Forecasting stock market trends is a challenging and rewarding task. This has led to extensive research into stock market behavior and the development of analytical and artificial intelligence tools for stock trading. The most promising application of artificial intelligence in finance is the use of neural networks. This thesis is concerned with the application of neural networks for the generation of stock market timing signals.

We have examined different analytical approaches to stock market trading. For the generation of trading signals, …