Engineering Commons^™

Reservoir Characterization Using Seismic Inversion Data, Subhash Kalla

LSU Doctoral Dissertations

Reservoir architecture may be inferred from analogs and geologic concepts, seismic surveys, and well data. Stochastically inverted seismic data are uninformative about meter-scale features, but aid downscaling by constraining coarse-scale interval properties such as total thickness and average porosity. Well data reveal detailed facies and vertical trends (and may indicate lateral trends), but cannot specify intrawell stratal geometry. Consistent geomodels can be generated for flow simulation by systematically considering the precision and density of different data. Because seismic inversion, conceptual stacking, and lateral variability of the facies are uncertain, stochastic ensembles of geomodels are needed to capture variability.

In this …

Optimal Robust Fault Detection, Nike Liu

LSU Doctoral Dissertations

This dissertation gives complete, analytic, and optimal solutions to several robust fault detection problems for both continuous and discrete linear systems that have been considered in the research community in the last twenty years. It is shown that several well-recognized robust fault detection problems, such as H_minus\H_2, H_2\ H_infinity and H_infinity\H_infinity problems, have a very simple optimal solution in an observer form by solving a standard algebraic Riccati equation. The optimal solutions to some other robust fault detection problems, such as H_minus\H_2 and H_2\H_2 problems are also given. In addition, it is shown that some well-studied and seeming sensible optimization …

Adsorption And Photochemical Transformation Of Polycyclic Aromatic Hydrocarbons On Atmospheric Water Films, Jing Chen

LSU Doctoral Dissertations

Atmospheric water films affect the processing of chemicals in the atmosphere and have potential effects on human health and the environment. In this work, adsorption and photochemical transformations of gas-phase PAHs were studied in a flow-tube photo-reactor with a view to understanding the behavior of gas-phase PAHs occurring in thin water films such as those of aerosols and fog. Naphthalene and phenanthrene were chosen as model PAHs for this study. Bulk water-air and air-to-interface partition constants of naphthalene and phenanthrene were estimated from the experiments based on the dependence of the equilibrium uptake on the water film thickness. Theoretical computations …

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 …

Elasto-Plastic And Damage Modeling Of Reinforced Concrete, Ziad N. Taqieddin

LSU Doctoral Dissertations

Modeling the mechanical behavior of Reinforced Concrete (RC) is still one of the most difficult challenges in the field of structural engineering. The Nonlinear Finite Element Analysis (NFEA) and modeling of the behavior of RC members are the primary goals of this study. The macroscopic components of RC, Concrete material and reinforcing steel, are represented herein by separate material models. These material models are combined together using a model that describes the global effect of interaction between reinforcing steel and concrete in order to simulate the behavior of the composite RC material. A thermodynamically consistent constitutive model for concrete that …

Thermomechanical Interaction Analysis Of Bodies Subjected To Oscillatory Heat Source, Jun Wen

LSU Doctoral Dissertations

Surface heating by application of a moving heat source is a common problem in most manufacturing processes as well as in many tribological applications. The existing literature on studies of moving heat source problems primarily concentrates on unidirectional moving heat sources. Yet, a more complete analysis requires understanding of thermal behavior of bodies in relative sliding contacts subjected to oscillatory heat sources and thermomechanical interaction. In this dissertation, two analytical models are developed for rapid evaluation of the transient temperature in solids undergoing oscillatory heat source. In the first model, an analytical technique is presented to treat oscillatory heat source …

Numerical Modeling Of Continuous Flow Microwave Heating - Coupling Of High Frequency Electromagnetism With Fluid Flow And Heat Transfer, Deepti Salvi

LSU Doctoral Dissertations

This study focused on numerical and experimental investigation of continuous flow microwave heating. A numerical model was developed to predict the temperature of a liquid product heated in a continuous-flow focused microwave system by coupling electromagnetism, fluid flow, and heat transfer in two different software packages (ANSYS Multiphysics 9.0 and COMSOL Multiphysics 3.4). The temperature and energy distributions simulated in ANSYS were verified against other numerical studies published in the literature. Comparison of the simulated temperature in ANSYS with experimental data for salt water of two different salinities showed good agreement. To simulate the experimental conditions more accurately, a comprehensive …

A Study Of Regret And Rejoicing And A New Mcdm Method Based On Them, Xiaoting Wang

LSU Doctoral Dissertations

Multi-criteria decision-making (MCDM) is one of the most widely used decision methodologies in the sciences, business, and engineering worlds. MCDM methods aim at improving the quality of decisions by making the process more explicit, rational, and efficient. One controversial problem is that some well-known MCDM methods, like the additive AHP methods and the ELECTRE II and III methods, may cause some types of rank reversal problems. Rank reversal means that the ranking between two alternatives might be reversed after some variation occurs to the decision problem, like adding a new alternative, dropping an old alternative or replacing a non-optimal alternative …

Optimization Of Treatment Of Chlorinated Volatile Organic Compound Mixtures In Constructed Wetlands: Vegetation And Substrate Effects, Stephen Emmanuel Mbuligwe

LSU Doctoral Dissertations

Microcosm and mesocosm scale experiments were carried out to investigate the effects of vegetation and substrates on the performance of engineered wetland systems (EWSs) meant to treat mixtures of volatile organic compounds (cVOCs). The experiments were conducted with a view to optimizing contributions of these wetland components. Phragmites communis and Typha latifolia, the commonest wetland plant species, were compared in mesocosm scale EWSs. Eight common wetland plant species were compared using microcosm experiments based on the potential of their rootmatter to enhance treatment of cVOC mixtures. Twelve common wetland plants were similarly compared but on the basis of their aboveground …

Heterogeneous Catalyzed Macromolecular Hydrogenations In Oscillating Systems, Alan Bussard

LSU Doctoral Dissertations

An examination of novel oscillatory (alternating gas and liquid phase) reactors and heterogeneous catalysts for multi-phase macromolecular reactions was carried out. A monolith-containing square die with Pd/Al2O3 catalysts was used to successfully hydrogenate poly(styrene) (PS). The inherent pulse behavior of the extruder was found to be sufficient to approach intrinsic kinetics at low polymer concentrations. At higher (10 wt% PS) concentrations, forced pulsing was shown to have a greater impact on observed reaction rates. Selectivity with this extruder-fed reactor was better than with a stirred tank in all cases, due to a more plug-flow-like residence time distribution. While accurate control …

Bayesian Model Averaging On Hydraulic Conductivity Estimation And Groundwater Head Prediction, Xiaobao Li

LSU Doctoral Dissertations

Characterization of aquifer heterogeneity is inherently difficult because of the insufficiency of data, the inflexibility of parameterization methods, and non-uniqueness of parameterization methods. Groundwater predictions are greatly affected by multiple interpretations of aquifer properties and the uncertainties of model parameters. This study introduces a Bayesian model averaging (BMA) method along with multiple generalized parameterization (GP) methods to identify hydraulic conductivity and along with multiple simulation models to predict groundwater head and quantify the prediction uncertainty. Two major issues about BMA are discussed. The first problem is with using Occam’s window in usual BMA applications. Occam’s window only accepts models in …

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 …

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 …

Identification Of Polycyclic Aromatic Hydrocarbons In The Supercritical Pyrolysis Products Of Synthetic Jet Fuel S-8 And Methylcyclohexane, Jorge Oswaldo Ona Ruales

LSU Doctoral Dissertations

Inside the pre-combustor fuel lines of future high-speed aircraft, at supercritical conditions, hydrocarbon fuels react to form polycyclic aromatic hydrocarbons (PAH) and eventually solid deposits. These deposits can block fuel lines and lead to undesirable effects for the aircraft operation. To elucidate the pathways that lead to the formation of PAH (and ultimately, solids formation), the identification of the PAH products generated by the reactions is critical. In this context, two fuels have been analyzed: synthetic jet fuel S-8 and methylcyclohexane. Synthetic jet fuel S-8 is important due to its non-petroleum origin. Methylcyclohexane is important due to its endothermic behavior. …

Fate And Transport Of Microorganisms In Coastal Subsurface-Experiment And Modeling, Haibo Cao

LSU Doctoral Dissertations

The objective of this dissertation was to investigate the fate and transport of microorganisms in coastal subsurface. Two topics were studied: (1) evaluation of the performance of the Marshland Upwelling System (MUS) in removing fecal bacteria and the background recovery after it is shut down; (2) Investigation of the effects of salinity and soluble organic matter (SOM) on sorption of MS-2 and development of a model to describe the sorption and transport process. The MUS showed effective performance in removing fecal bacteria during its 32 month operation period at Bayou Segnette Site. The removal efficiency was increased with its operation …

Quiescent Current Testing Of Cmos Data Converters, Siva Yellampalli

LSU Doctoral Dissertations

Power supply quiescent current (IDDQ) testing has been very effective in VLSI circuits designed in CMOS processes detecting physical defects such as open and shorts and bridging defects. However, in sub-micron VLSI circuits, IDDQ is masked by the increased subthreshold (leakage) current of MOSFETs affecting the efficiency of I¬DDQ testing. In this work, an attempt has been made to perform robust IDDQ testing in presence of increased leakage current by suitably modifying some of the test methods normally used in industry. Digital CMOS integrated circuits have been tested successfully using IDDQ and IDDQ methods for physical defects. However, testing of …

Cluster Kinetics Modeling Of Glassforming Materials, Lisa Ann Brenskelle

LSU Doctoral Dissertations

In this work, a new model relating temperature and pressure to dielectric relaxation or viscosity of a glassformer is developed. The model is based upon cluster kinetics, reaction-like mechanisms describing interactions between glassformer monomers and their clusters. Mathematical solutions of population balance equations for monomer and cluster lead to molar concentrations in terms of rate coefficients of the reaction-like mechanisms. These are then related to viscosity or dielectric relaxation time through free volume theory. The resulting equations are tested against data for a variety of pure glassformers, fragile, non-fragile, large, and small molecules over a wide range of temperatures, pressures, …

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 …

Mercury Transport Through A Capped Sediment, Jianrong Liu

LSU Doctoral Dissertations

Laboratory simulation cells were employed to evaluate the effectiveness of a sand cap for containing highly mercury-contaminated lake sediments and the resultant impacts on the mercury fate beneath the cap. Sand cap can delay and reduce the migration of mercury into the overlying water; however, due to the small partition coefficient of mercury between sand and water, a capping material with higher partition coefficient is better for the long-term containment of mercury. In the following study, efforts were made to identify and investigate an active capping material which works effectively at containing and inhibiting the methylation of mercury. Based on …

Redutive Dehalogenation Of Chlorinated Alkanes By Novel Bacteria At The Petroprocessor Of Louisiana Inc. Superfund Site, Jun Yan

LSU Doctoral Dissertations

A reductively dehalogenating enrichment culture was established using chloroalkane-contaminated groundwater from the PetroProcessors of Louisiana, Inc. (PPI) Superfund site. Two novel, strictly anaerobic bacterial strains, designated as BL-DC-8 and BL-DC-9, were isolated from the enrichment culture. These strains represent the first bacteria known to anaerobically dehalogenate 1,2,3-trichloropropane, the degradation pathway of which was determined. Both strains could be cultured in completely defined basal medium and were also able to dehalogenate a variety of other vicinally chlorinated alkanes including 1,1,2,2-tetrachloroethane, 1,1,2-trichloroethane, 1,2-dichloroethane, and 1,2-dichloropropane via dichloroelimination reactions. Chlorinated alkanes containing only a single chlorine substituent (1-chloropropane, 2-chloropropane), chlorinated alkenes (tetrachloroethene, trichloroethene, …

Continuous Reservoir Model Updating By Ensemble Kalman Filter On Grid Computing Architectures, Xin Li

LSU Doctoral Dissertations

A reservoir engineering Grid computing toolkit, ResGrid and its extensions, were developed and applied to designed reservoir simulation studies and continuous reservoir model updating. The toolkit provides reservoir engineers with high performance computing capacity to complete their projects without requiring them to delve into Grid resource heterogeneity, security certification, or network protocols.

Continuous and real-time reservoir model updating is an important component of closed-loop model-based reservoir management. The method must rapidly and continuously update reservoir models by assimilating production data, so that the performance predictions and the associated uncertainty are up-to-date for optimization. The ensemble Kalman filter (EnKF), a Bayesian …

Electrochemical Fabrication Of Auco Nanostructures, Maoshi Guan

LSU Doctoral Dissertations

Electrodeposited Au/CoAu multilayered nanowires are materials with alternating layers of Au and CoAu in a wire where the layer thickness and wire diameter are nanometer size. They can be used for different applications. For example, the wires may exhibit giant magnetoresistance (GMR), a change in the materials resistance with a magnetic field, having applications as a sensor material for microdevices. If Co is etched from CoAu nanowires, rough, porous gold nanostructures will be left behind, which could be used as novel catalysts. In this study, the electrodeposition of Au/CoAu multilayered nanowires and nanotubes in nanoporous templates was explored from a …

Moderately-Rapid Assessment Of Alkaline Desiccation Environmental Systems, David Alan Bates

LSU Doctoral Dissertations

A moderately-rapid assessment tool was developed to analyze the waterless desiccation compost toilet investigated in a rural Mexican setting. Over 100 social factors were identified along with the applicable technical factors that influenced the low acceptability of the toilets. A 4-point rating scale was developed to increase the ability and speed of analyzing both the social and technical data. The treatment process was an alkaline-desiccation process with mean pH values of 8.2 ± sd 1.1 and water content of 18.3% ± sd 9.9, which resulted in mean fecal coliform values of 15.0 MPN/g ± sd 31.8, drastically lower than the …

An Experimental Study On The Formation Of Polycyclic Aromatic Hydrocarbons During The Pyrolysis And Oxidation Of Catechol[Ortho-Dihydroxybenzene]-A Model Compound Representative Of Structural Units In Coal, Wood, And Biomass, Shiju Thomas

LSU Doctoral Dissertations

Polycyclic aromatic hydrocarbons (PAH) formed during the pyrolysis and combustion of solid fuels like coal, wood, and biomass are widespread environmental pollutants. Since some PAH are known to exhibit carcinogenic and mutagenic activity, understanding the chemical reactions responsible for PAH formation is of utmost importance. To better understand the reactions leading to the formation of PAH from complex solid fuels, pyrolysis and oxidation experiments have been performed in an isothermal laminar-flow reactor, using the model fuel catechol (ortho-dihydroxybenzene), a phenol-type compound representative of structural entities in coal, wood, and biomass. Catechol pyrolysis experiments have also been performed in the presence …

Current Transport Modeling Of Carbon Nanotube Field Effect Transistors For Analysis And Design Of Integrated Circuits, Jose Mauricio Marulanda Prado

LSU Doctoral Dissertations

The purpose of this study was to develop a complete current transport model for carbon nanotube field effect transistors (CNT-FETs) applicable in the analysis and design of integrated circuits. The model was derived by investigating the electronic structure of carbon nanotubes and using basic laws of electrostatics describing a field effect transistor. We first derived analytical expressions for the carrier concentration in carbon nanotubes for different chiral vectors (n,m) by studying and characterizing their electronic structure. Results showed a strong relation to the diameter and wrapping angle of carbon nanotubes. The charge distribution in a CNT-FET is characterized from the …

Catalytic Synthesis Of Ethanol From Biomass-Derived Syngas, Adefemi Adelanwa Egbebi

LSU Doctoral Dissertations

Syngas produced by gasification of biomass or coal can be converted directly to ethanol and higher alcohols by processes based on heterogeneous catalysts. Ethanol can be used as a neat fuel or fuel additive or as a hydrogen carrier. Rhodium-based catalysts have been found to be most selective for the formation of C₂ oxygenates from the hydrogenation of CO when suitably promoted. Here, we explore the effects of Mn, Fe, and Li promoters on Rh/TiO₂. Rh-TiO₂, Rh-Li/TiO₂, Rh-Mn/TiO₂, Rh-Mn-Li/TiO₂ and Rh-Mn-Li-Fe/TiO₂ catalysts were tested for the hydrogenation of CO …

Stochastic Demand Forecast And Inventory Management Of A Seasonal Product A Supply Chain System, Mohammad Anwar Ashek Rahman

LSU Doctoral Dissertations

Estimation of seasonal demand prior to an active demand season is essential in supply chain management. The business cycle of the seasonal demand is divided into two stages: stage-1, the slow-demand period, and stage-2, the peak-demand period. The focus here is to determine an appropriate demand forecast for the peak-demand period. In the first set of forecasting model, a standard gamma and an inverse gamma prior distribution are used to forecast demand. The parameters of the prior model are estimated and updated based on current observation using Bayesian technique. The forecasts are derived for both complete and incomplete datasets. The …

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 …

Cryopreservation Of Adipose Derived Adult Stem Cells And Multidimensional Cell Sheets, Sreedhar Thirumala

LSU Doctoral Dissertations

Human adipose tissue provides a uniquely abundant and accessible source of adult stem cells. In response to chemical, hormonal or structural stimuli, these human adipose-derived adult stem (ASCs) cells can differentiate along multiple lineage pathways, including adipocytes, chondrocytes, myocytes, neurons and osteoblasts. Successful cryopreservation of scientifically and commercially important ASCs would revolutionize the tissue engineering and regenerative medicine industry. In this research, we have investigated the water transport phenomenon during freezing of several passages of adipose derived adult stem cells and generated the membrane permeability parameters in the presence and absence of cryoprotective agents. These measured permeability parameters were then …

Replication Of Metal-Based Microscale Structures By Compression Molding: A Combined Experimental And Finite Element Analysis Study, Jing Jiang

LSU Doctoral Dissertations

Fabrication of microscale Ta mold inserts by micro-electrical-discharge-machining (ìEDM) is reported. Morphology, chemistry, and structure of the near-surface region of as-machined Ta blanks have been characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy. A TaC surface layer forms on as-machined Ta surfaces. This altered surface layer was removed by electro-chemical-polishing. Further modification of Ta insert surfaces was accomplished by deposition of a conformal Ti-containing hydrogenated carbon coating. We demonstrate successful replication of high-aspect-ratio microscale structures (HARMS) in Al and Cu by compression molding with such surface-engineered Ta mold inserts. In addition, a hybrid microfabrication technique, combining …