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Characterization Of Syntactic Foams And Their Sandwich Composites: Modeling And Experimental Approaches, Nikhil Gupta

LSU Doctoral Dissertations

Hollow particle filled polymers known as syntactic foams are lightweight and highly damage tolerant. Syntactic foams are used as core materials in sandwich composites. The use of such materials in aeronautical and space structures make it necessary to understand their characteristics for various environmental and loading conditions. The first part of the present work takes modeling and finite element analysis approach to understand and predict the deformation behavior of syntactic foams. Contact analysis is performed on single particle models by the finite element analysis approach. In the second part extensive experiments are carried out to characterize syntactic foams for hygrothermal …

Rainfall-Runoff Control: Variably Saturated Transport For An Infiltration System Controlling Water Quality And Quantity, Zheng Teng

LSU Doctoral Dissertations

Rainfall-runoff impacted by anthropogenic activities transports significant quantities of particulate, aqueous and complexed constituents. These diffuse, unsteady and stochastic event-based loadings are unique challenges for water quality and quantity control. The design, water quality and quantity functions of a partial exfiltration reactor (PER) utilizing Fe-coated-sand and porous pavement (CPP) is examined specifically across three representative rainfall-runoff events. Total concentrations and mass for metals (Zn, Pb, Cu and Cd), suspended solids, and Chemical oxygen demand were reduced significantly. Rainfall-runoff volume and peak flow were reduced and time to peak was extended. Influent dm/dp ratios based on particle analyses suggest that the …

Hydrodynamic And Sediment Transport Modeling Of Deltaic Sediment Processes, Hassan Shahid Mashriqui

LSU Doctoral Dissertations

This dissertation tests the hypothesis that the early phases of deltaic bar and distributary channel formation and sediment transport on an adverse slope could be simulated with a 2D finite element sediment transport model. The models used were RMA2 and SED2D modules of the TABS-MD model suite. A finite element mesh of the lower Atchafalaya River and the delta was developed, using the Surface Water Modeling System (SMS) software package. Calibration and validation of the model were performed, using data collected during field surveys and from available Atchafalaya River archived flow, suspended sediment, and dredging records. In a test simulation …

Dynamic Modeling And Parameter Estimation For An Ethlyene-Propylene-Diene Polymerization Process, Rujun Li

LSU Doctoral Dissertations

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A general dynamic model for continuous EPDM polymerization in which crosslinking and gel formation are attributable to reactions between pendant double bonds has been developed. A pseudo-kinetic rate constant method is introduced to construct a moment model for a pseudo-homopolymer that approximates the behavior of the actual terpolymer under long chain and quasi-steady state assumptions. The pseudo-homopolymer model is then used as the basis for application of the numerical fractionation method. The proposed dynamic model is capable of predicting polydispersities and molecular weight distributions near the gel point with as few as eleven generations, and in the …

Progressive Fatigue Effects On Manual Lifting Factors, Anthony D'Wayne Banks

LSU Doctoral Dissertations

Much evidence suggests that the cause of lower back pain (LBP) and injury is frequently related to the posture of lifting, the load, muscle fatigue, and other factors. The purpose of this study was to evaluate the effect of progressive fatigue on factors that have previously been associated with increased risk of LBP in various occupational settings, during a repetitive lifting task where freestyle lifting technique was utilized. A laboratory experiment was conducted to evaluate several fatigue analysis, electromyography amplitude, kinematic, and kinetic parameters of repetitive freestyle lifting during a 2-hour lifting period. Each of ten (10) young adult male …

Bioavailability And Bioaccumulation Of Sediment-Associated, Desorption-Resistant Fraction Of Polycyclic Aromatic Hydrocarbon Contaminants, Xiaoxia Lu

LSU Doctoral Dissertations

This study is directed toward identifying and characterizing the bioavailability of both reversibly sorbed and desorption-resistant fraction of hydrophobic organic contaminants in natural biologically active sediments and the corresponding consequences to prediction, control and regulation of these contaminants. The focus is on polycyclic aromatic hydrocarbons (PAHs) with particular emphasis on phenanthrene and benzo[a]pyrene. A quantity of well-characterized and extensively desorbed sediments was prepared by desorbing the lab-inoculated sediment with an isopropanol and electrolyte solution. This procedure was proved to be a very effective method to prepare sediments containing contaminants largely limited to a desorption-resistant compartment. Accumulation of contaminants in the …

Treatment Of Chlorinated Volatile Organic Compounds Using Wetland Systems, Gabriel Roderick Kassenga

LSU Doctoral Dissertations

Bench-scale continuous vertical flow column and microcosm studies were conducted to investigate the attenuation potential of chlorinated volatile organic compounds (CVOCs) in constructed wetland soil mixtures prepared from peat, compost and sand and in a pristine natural freshwater wetland soil. The study also determined geotechnical properties of potential synthetic peat mixtures for construction of treatment wetlands for CVOCs. Trichloroethene (TCE), cis-1,2-dichloroethene (cis-1,2-DCE) and 1,2-dichloroethane (1,2-DCA) were the main test chemicals used during the studies. Based on geotechnical and sorption characteristics, two mixtures (one comprised of sand and peat and the other comprised of sand, peat and compost product) were selected …

Electrodeposition Of Nickel-Copper Alloys And Nickel-Copper-Alumina Nanocomposites Into Deep Recesses For Mems, Amrit Panda

LSU Doctoral Dissertations

Electrodeposition is an important component in the fabrication of micro electro mechanical systems (MEMS). Nickel is the most commonly used material to produce three dimensional microstructures and few material alternatives have been demonstrated. In this dissertation, electrodeposited Ni-Cu alloys and nanocomposites are investigated as possible replacements for nickel in microsystems. Ni-Cu alloys are attractive for their corrosion resistance, magnetic and thermophysical properties. Alumina nanoparticulates included into metal matrices improve hardness and tribology of deposits. The Ni-Cu alloys and Ni-Cu-g-Al2O3 nanocomposites were electrodeposited from a citrate electrolyte, both at low and high pH. Electrodeposition experiments were performed in recessed microelectrodes 500 …

Finite-Horizon Operations Planning For A Lean Supply Chain System, Ahmad Diponegoro

LSU Doctoral Dissertations

This dissertation studies an operational policy for a lean supply chain system consisting of a manufacturer, multiple suppliers and multiple buyers. The manufacturer procures raw materials from the suppliers and converts them into finished products, which are then shipped in batches to the buyers at certain intervals of times. Three distinct but inseparable problems are addressed: single supplier and single buyer with fixed delivery size (FD), multiple suppliers and multiple buyers with individual delivery schedule (MD), and time dependent delivery quantity with trend demand (TD). The mathematical formulations of these supply systems are categorized as mixed-integer, nonlinear programming problems (MINLAP) …

Clay Landfill Liners Subject To Variable Interfacial Redox And Ph Conditions-Heavy Metal And Clay Interactions, Ping Zhou

LSU Doctoral Dissertations

Municipal landfill leachate contains high levels of metal species, including Cu, Zn, Cd and Pb generating competitive interactions between these metal species and the landfill clay liner materials. Characterization of the clay fraction, physical and chemical characteristics of landfill clay liner materials, the competitive interaction of metal species with clay liner materials, the kinetic modeling of metal species transport in clay liner, and the effect of cyclic interfacial redox potential on the structural changes to the clay liner and leachate metal transport were investigated in this study. The clay liner materials studied included Na-bentonite, kaolinite and Amite soil (sandy silty …

Block-Level Discrete Cosine Transform Coefficients For Autonomic Face Recognition, Willie L. Scott, Ii

LSU Doctoral Dissertations

This dissertation presents a novel method of autonomic face recognition based on the recently proposed biologically plausible network of networks (NoN) model of information processing. The NoN model is based on locally parallel and globally coordinated transformations. In the NoN architecture, the neurons or computational units form distributed networks, which themselves link to form larger networks. In the general case, an n-level hierarchy of nested distributed networks is constructed. This models the structures in the cerebral cortex described by Mountcastle and the architecture based on that proposed for information processing by Sutton. In the implementation proposed in the dissertation, the …

Optimization Of The Light Dynamics In The Hydraulically Integrated Serial Turbidostat Algal Reactor (Histar), Barbara Christine Benson

LSU Doctoral Dissertations

The research objective was the optimization of light dynamics in a Hydraulically Integrated Serial Turbidostat Algal Reactor (HISTAR). A deterministic model of HISTAR productivity that was responsive to manipulations of photosynthetic photon flux fluence rate (PPFFR) was developed, calibrated, and applied. A series of experiments was conducted to define the mathematical equations that best describe three relationships. The first relationship was between the elevation (E) of the light source and the culture surface PPFFR (I_o). The second relationship was between the biomass concentration (X) in the experimental unit and the average PPFFR in the reactor (I_a). …

Rotary Kiln Incineration Of Hazardous Wastes: Pilot-Scale Studies At Louisiana State University, John Sutherland Earle

LSU Doctoral Dissertations

Studies of incineration of surrogates for hazardous wastes are conducted in the pilot-scale rotary kiln incinerator (RKI) at Louisiana State University (LSU) in Baton Rouge, Louisiana. The purpose of the research is to investigate methods of treating and destroying hazardous wastes in a cost-effective and environmentally sound way. The objective is to provide process data that will contribute to increased knowledge for RKI design and operation. The LSU facility is a College of Engineering Combustion Laboratory that is unique in its large size as a university laboratory. It is equipped with individual instruments for analysis of O₂, CO, …

Mechanisms And Control Of Water Inflow To Wells In Gas Reservoirs With Bottom Water Drive, Miguel Armenta

LSU Doctoral Dissertations

Water inflow may cease production of gas wells, leaving a significant amount of gas in the reservoir. Conventional technologies of gas well dewatering remove water from inside the wellbore without controlling water at its source. This study addresses mechanisms of water inflow to gas wells and a new completion method to control it. In a vertical oil well, the water cone top is horizontal, but in a gas well, the gas/water interface tends to bend downwards. It could be economically possible to produce gas-water systems without water breakthrough. Non-Darcy flow effect (NDFE), vertical permeability, aquifer size, density of well perforation, …

Improved Bottomhole Pressure Control For Underbalanced Drilling Operations, Carlos Perez-Tellez

LSU Doctoral Dissertations

Maintaining underbalanced conditions from the beginning to the end of the drilling process is necessary to guarantee the success of jointed-pipe underbalanced drilling (UBD) operations by avoiding formation damage and potential hazardous drilling problems such as lost circulation and differential sticking. However, maintaining these conditions is an unmet challenge that continues motivating not only research but also technological developments. This research proposes an UBD flow control procedure, which represents an economical method for maintaining continuous underbalanced conditions and, therefore, to increase well productivity by preventing formation damage. It is applicable to wells that can flow without artificial lift and within …

Investigation Of Bond Slip Between Concrete And Steel Reinforcement Under Dynamic Loading Conditions, John Henry Weathersby

LSU Doctoral Dissertations

Structural failures during recent earthquakes and terrorist attacks have demonstrated shortcomings in the design procedures for reinforced concrete structures. Earlier research has demonstrated that a major limitation of the Finite Element (FE) modeling of the response of reinforced concrete is the accurate modeling of the interaction of the concrete with the steel reinforcement. Presently, there are insufficient data on the dynamic nonlinear interaction between the concrete material and the steel reinforcement to develop a numerical model of this interaction. The primary objective of this study was to experimentally investigate the dynamic interaction (bond slip) of reinforcement with concrete and gain …

Optimization And Automation Of A Thermal Oyster Shucking Process, Daniel Edgar Martin

LSU Doctoral Dissertations

Louisiana Gulf Coast oysters (Crassostrea virginica) were subjected to thermal shucking treatments to effect adductor muscle release from both left and right valves. The oysters were instrumented with thermocouples to monitor and record process temperatures in the oysters and on the shell. Following treatment, the oysters were evaluated for relaxation and release of the adductor muscle, meat quality and texture, and for the effect of the treatments on the storage life of the oysters as measured by total microbial plate counts. The treatments of many oysters resulted in a complete release of the adductor muscle from the shell while maintaining …

Manufacturing And Analysis Of A Liga Heat Exchanger For The Surface Of A Tube: A Cooling Simulation Of The Leading Edge Region Of A Turbine Blade, Christophe Marques

LSU Doctoral Dissertations

Fabricating nickel micro heat exchangers directly on planar or non-planar metal surfaces has been demonstrated using the LIGA micromachining process. These heat exchangers can effectively control the temperature of surfaces in high heat flux applications. Of particular interest is the temperature control of gas turbine engine components. The locations in the gas turbine engine where improved, efficient cooling is required includes gas turbine blades, stator vanes, the turbine disk, and the combustor liner. In this dissertation, the primary application of interest is the use of such heat exchangers to cool airfoils such as turbine blades. In the first part of …

Granulometry, Chemistry And Physical Interactions Of Non-Colloidal Particulate Matter Transported By Urban Storm Water, Hong Lin

LSU Doctoral Dissertations

Urban rainfall-runoff is a major source of anthropogenic pollutions to the natural water bodies. Particulate matter generated from anthropogenic environments and activities is a constituent of environmental concern as well as a carrier substrate for reactive contaminants such as metals. Partitioning, transport and transformation of particulate-bound contaminants are determined by the granulometry, physical and geochemical properties of the particulate carriers. Previous research emphasized in the transport of colloidal and suspended particles in rainfall-runoff. The settleable and sediment material were ignored though they are a major granulometric fraction which may contain most of the sorbed or transported constituents such as metals, …

Solute Transport In A Porous Medium: A Mass-Conserving Solution For The Convection-Dispersion Equation In A Finite Domain, William Golz

LSU Doctoral Dissertations

This dissertation considers the proper mathematical description for the physical problem of a miscible solute undergoing longitudinal convective-dispersive transport with constant production, first-order decay, and equilibrium sorption in a porous medium. Initial and input concentrations may be any continuously differentiable functions and the mathematical system is articulated for a finite domain. This domain yields a mass balance which requires Robin (i.e., third-type) boundaries, which describe a continuous flux but a discontinuous resident-concentration. The discontinuity in the resident concentration at the outflow boundary yields an underdetermined system when the exit concentration is not experimentally measured. This is resolved by defining the …

Advanced Turbulence Modeling For Industrial Flows, Raymond Michael Jones

LSU Doctoral Dissertations

This dissertation deals with the development of an improved two-equation turbulence model and its application to various flows. Six different conventional turbulence models were initially tested for predicting the flow inside of an unbaffled stirred tank reactor (STR), and the results are compared with experimental LDV data. Each of the models use low Reynolds number corrections. Results indicate that the radial velocity component in the impeller discharge region is overpredicted by each of the models. The tangential velocity component in the impeller discharge region is predicted well by the models, but is underpredicted near the shaft. The low Reynolds number …

The Transcendental Eigenvalue Problem And Its Application In System Identification, Kumar Vikram Singh

LSU Doctoral Dissertations

An accurate mathematical model is needed to solve direct and inverse problems related to engineering analysis and design. Inverse problems of identifying the physical parameters of a non-uniform continuous system based on the spectral data are still unsolved. Traditional methods, for the system identification purpose, describe the continuous structure by a certain discrete model. In dynamic analysis, finite element or finite difference approximation methods are frequently used and they lead to an algebraic eigenvalue problem. The characteristic equation associated with the algebraic eigenvalue problem is a polynomial. Whereas, the spectral characteristic of a continuous system is represented by certain transcendental …

Large Eddy Simulations Of Complex Turbulent Flows, Mayank Tyagi

LSU Doctoral Dissertations

In this dissertation a solution methodology for complex turbulent flows of industrial interests is developed using a combination of Large Eddy Simulation (LES) and Immersed Boundary Method (IBM) concepts. LES is an intermediate approach to turbulence simulation in which the onus of modeling of “universal” small scales is appropriately transferred to the resolution of “problem-dependent” large scales or eddies. IBM combines the efficiency inherent in using a fixed Cartesian grid to compute the fluid motion, along with the ease of tracking the immersed boundary at a set of moving Lagrangian points. Numerical code developed for this dissertation solves unsteady, filtered …

Design Of Optimal Equalizers And Precoders For Mimo Channels, Lijuan Li

LSU Doctoral Dissertations

Channel equalization has been extensively studied as a method of combating ISI and ICI for high speed MIMO data communication systems. This dissertation focuses on optimal channel equalization in the presence of non-white observation noises with unknown PSD but bounded power-norm. A worst-case approach to optimal design of channel equalizers leads to an equivalent optimal H-infinity filtering problem for the MIMO communication systems. An explicit design algorithm is derived which not only achieves the zero-forcing (ZF) condition, but also minimizes the RMS error between the transmitted symbols and the received symbols. The second part of this dissertation investigates the design …

Analytical Study On Flood Induced Seepage Under River Levees, Senda Ozkan

LSU Doctoral Dissertations

A common and potentially dangerous phenomenon associated with flooding is seepage under levees and the formation of sand boils. Seepage flow due to hydrostatic head gradients of floods may cause deformation of pervious layers leading to heave, piping and sand boils. Underseepage may also cause irreversible changes in the characteristics of the porous medium. A series of independent flood events may have cumulative effects on pervious layers causing sand boils to grow. Current underseepage analyses for levees are based on steady-state flow. Transient seepage flow due to rapid changes in river head may contribute to cumulative effects and cause critical …

On Implementing Dynamically Reconfigurable Architectures, Hatem Mahmoud El-Sayed El-Boghdadi

LSU Doctoral Dissertations

Dynamically reconfigurable architectures have the ability to change their structure at each step of a computation. This dissertation studies various aspects of implementing dynamic reconfiguration, ranging from hardware building blocks and low-level architectures to modeling issues and high-level algorithm design. First we derive conditions under which classes of communication sets can be optimally scheduled on the circuit-switched tree (CST). Then we present a method to configure the CST to perform in constant time all communications scheduled for a step. This results in a constant time implementation of a step of a segmentable bus, a fundamental dynamically reconfigurable structure. We introduce …