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Numerical Simulations Of Incompressible Flows In Complex Geometries., Konstantinos Vogiatzis
Numerical Simulations Of Incompressible Flows In Complex Geometries., Konstantinos Vogiatzis
LSU Historical Dissertations and Theses
A mainly spectral code along with domain-decomposition, a combination that is not widely in use in complex problems, has been developed for the solution of the 3-D unsteady incompressible Navier-Stokes equations. The code uses fully spectral or a combination of spectral-collocation and finite difference approximations and a 3-step splitting time-marching scheme. The developed Poisson solver utilizes matrix diagonalization and incorporates a direct sub-structuring method based on the influence matrix technique. As a first step, laminar and turbulent confined flows were simulated, initially with DNS, then with LES, using a modified Smagorinksi model. The domain-decomposition technique and parallel implementation were tested …
Analysis And Mathematical Modeling Of Autonomously Oscillating Yeast Cultures., Abdelqader M. Zamamiri
Analysis And Mathematical Modeling Of Autonomously Oscillating Yeast Cultures., Abdelqader M. Zamamiri
LSU Historical Dissertations and Theses
The conditions that precede the onset of autonomous oscillations in continuous yeast cultures were studied in three different types of experiments. It was found that the final state of the culture depends on the protocol used to start-up the reactor. Reaching the desired operating point by slow dilution rate changes gave rise to different final states, two oscillatory states and one steady state, depending on the rate of change in dilution rate. The multiplicity of stable states at a single operating point is not explained by current distributed models and points towards a segregated mechanism of these oscillations. The ability …
Novel Formulation And Application Of Model Predictive Control., Guang-Yan Zhu
Novel Formulation And Application Of Model Predictive Control., Guang-Yan Zhu
LSU Historical Dissertations and Theses
Model predictive control (MPC) has been extensively studied in academia and widely accepted in industry. This research has focused on the novel formulation of model predictive controllers for systems that can be decomposed according to their nonlinearity properties and several novel MPC applications including bioreactors modeled by population balance equations (PBE), gas pipeline networks, and cryogenic distillation columns. Two applications from air separation industries are studied. A representative gas pipeline network is modeled based on first principles. The full-order model is ill-conditioned, and reduced-order models are constructed using time-scale decomposition arguments. A linear model predictive control (LMPC) strategy is then …
Active Control Of Thermoacoustical Instabilities., Daniel Ulises Campos-Delgado
Active Control Of Thermoacoustical Instabilities., Daniel Ulises Campos-Delgado
LSU Historical Dissertations and Theses
This dissertation presents some advances in active control of thermoacoustic instabilities in combustion chambers. Large-size gaseous and liquid fueled swirl stabilized combustors were used during the studies. Active control was implemented using different types of actuators. Proportional (loudspeakers and fuel valves) and discrete actuators (open-close automotive fuel injectors) were investigated. Acoustic and fuel modulation control were successfully applied. In large-scale combustors, flame stabilization techniques such as swirl add three dimensional characteristics to the flow. Moreover, the induced turbulence creates highly nonlinear interactions in the system. Thus, in order to capture these characteristics nonlinear partial differential equations have to be used. …
Design, Fabrication, And Testing Of Cross Flow Micro Heat Exchangers., Chad Randall Harris
Design, Fabrication, And Testing Of Cross Flow Micro Heat Exchangers., Chad Randall Harris
LSU Historical Dissertations and Theses
Cross flow micro heat exchangers were designed to maximize heat transfer from a liquid (water) to a gas (air) for a given frontal area while holding the pressure drop across the heat exchanger of each fluid to values characteristic of conventional scale heat exchangers (car radiators). The cross flow micro heat exchanger design is unique since it produces a very high rate of heat transfer/volume between dissimilar fluids with low fluid pressure drops. Predicted performance for two types of cross flow micro heat exchangers is compared to each other and to current innovative car radiators. Although the cross flow micro …
Control Of Supply Chain Systems By Kanban Mechanism., Shaojun Wang
Control Of Supply Chain Systems By Kanban Mechanism., Shaojun Wang
LSU Historical Dissertations and Theses
This research studies the control mechanism of a supply chain system to operate it efficiently and economically under the just-in-time (JIT) philosophy. To implement a JIT system, kanbans are employed to link different plants' production processes in a supply pipeline. Supply chain models may be categorized into single-stage, multi-stage, and assembly-line types of production systems. In order to operate efficiently and economically, the number of kanbans, the manufacturing batch size, the number of batches, and the total quantity over one period are determined optimally for these types of supply chains. The kanban operation at each stage is scheduled to minimize …
Plant Uptake Of Desorption Resistant Organic Chemicals From Sediments., Cesar Miguel Gomez Hermosillo
Plant Uptake Of Desorption Resistant Organic Chemicals From Sediments., Cesar Miguel Gomez Hermosillo
LSU Historical Dissertations and Theses
Two types of wetland plants, a woody species, black willow ( Salix nigra), and a non-woody, the macrophyte three-square bulrush (Scirpus olneyi), were used in laboratory studies to evaluate relationships between sorption, plant uptake, translocation and transpiration of phenanthrene, a model polycyclic aromatic hydrocarbon and chlorobenzene, a model chlorinated benzene from the reversible and desorption-resistant compartment of a sediment for Phenanthrene (PHEN) and a wetland soil for chlorobenzene (CB). The wetland soil is from The Petro Processors Inc. site (PPI), a 77-acre CERCLA facility located about 10 miles north of Baton Rouge, Louisiana. Other studies have evaluated the plant uptake …
A Study Of The Applicability Of Intrusion Technology For Evaluating Resilient Modulus Of Subgrade Soil., Ananda H. M. P. J Herath
A Study Of The Applicability Of Intrusion Technology For Evaluating Resilient Modulus Of Subgrade Soil., Ananda H. M. P. J Herath
LSU Historical Dissertations and Theses
The cone penetration test may be applied for estimation of the resilient modulus of subgrade soil. The main objectives of this study were to assess the applicability of the intrusion technology in evaluating the resilient characteristics of subgrade soil, develop models among the cone penetration test parameters, resilient modulus, soil properties, and stresses of subgrade soil, and to validate these models. Field cone penetration and laboratory tests were performed on different soil types. Disturbed and undisturbed soil samples were obtained close to the cone penetration test locations. Laboratory tests were also performed to obtain the resilient modulus, strength parameters, compaction …
Robust Control Of Uncertain Time -Delay Systems., Yun-Ping Huang
Robust Control Of Uncertain Time -Delay Systems., Yun-Ping Huang
LSU Historical Dissertations and Theses
Time-delay systems are common in industries. Direct analysis and synthesis of control systems with time delays are complicated and approximation methods such as Pade approximation are usually applied. However, the issues of control system robustness with respect to model uncertainties and approximation errors have not been sufficiently addressed. This dissertation focus on robustness of time-delay systems, especially robustness with respect to time delays, which has been discussed extensively using Lyapunov second method. We propose two methods in this dissertation to reformulate the problems into standard mu or Hinfinity problems. The first method involves representing the systems in linear functional transformation …
Mass Transfer Of 2,4,6-Trinitrotoluene And Lower Chlorinated Benzenes From Sediment Into Water., Marti Charleen Blad
Mass Transfer Of 2,4,6-Trinitrotoluene And Lower Chlorinated Benzenes From Sediment Into Water., Marti Charleen Blad
LSU Historical Dissertations and Theses
Bioremediation and phytoremediation are in their infancy and this research addresses concerns for application of these technologies. This laboratory and mathematical modeling effort predicts the pollutant flux from soils and sediments to the overlying waters. Little work has been done on transport in surface waters such as the slow moving and stagnant areas of the southern U.S. Mass transfer is a proposed rate limiting factor for biological transformation when using phytoremediation or natural attenuation. The research quantified mass transport of two dfferent contaminants, TNT and chlorinated benzenes, under different advective conditions. The TNT study was part of a "riffle-bed reactor" …
Development And Characterization Of Velocity Workspaces For The Human Knee., John Eric Fuller
Development And Characterization Of Velocity Workspaces For The Human Knee., John Eric Fuller
LSU Historical Dissertations and Theses
The knee joint is the most complex joint in the human body. A complete understanding of the physical behavior of the joint is essential for the prevention of injury and efficient treatment of infirmities of the knee. A kinematic model of the human knee including bone surfaces and four major ligaments was studied using techniques pioneered in robotic workspace analysis. The objective of this work was to develop and test methods for determining displacement and velocity workspaces for the model and investigate these workspaces. Data were collected from several sources using magnetic resonance imaging (MRI) and computed tomography (CT). Geometric …
Material Properties And Characteristics For Development Of An Expert System For Coal -Tar Sealers., James Edwin Shoenberger
Material Properties And Characteristics For Development Of An Expert System For Coal -Tar Sealers., James Edwin Shoenberger
LSU Historical Dissertations and Theses
Coal-tar sealers are used to protect asphalt pavements from damage by fuel spillage. The durability of these coal-tar sealers has been limited by the formation of cracks that occur in both in trafficked and non-trafficked areas and in all climatic regions. This cracking severely limits the useful life of the coal-tar sealer. Various coal-tar mixtures were evaluated through existing standard test methods. The mixtures varied through the source of the coal-tar emulsion, amount of aggregate, and amount of polymer used in the mixtures. The material properties of these mixtures were determined through curing, thermal, bending, tensile and stress-relaxation testing. The …
Biodegradation Of Desorption -Resistant Organic Contaminants In Wetland Soils., Sangjin Lee
Biodegradation Of Desorption -Resistant Organic Contaminants In Wetland Soils., Sangjin Lee
LSU Historical Dissertations and Theses
Contaminant bioavailability depends on physicochemical processes such as adsorption/desorption, diffusion, and dissolution. The rates of sorption and desorption of trichloroethylene (TCE) and 1,3-Dichlororbenzene (1,3-DCB) were studied. Desorption kinetics of 3-month and 5-month old contaminated soils showed that progressively less amount of contaminant was available for facile desorption compared to freshly contaminated soil in an empirical non-linear model. Microcosm batch studies were conducted to study the biodegradation of 1,3-DCB in the aqueous and soil phase containing a freshly contaminated soil and a soil containing only the desorption resistant fraction. The presence of the soil reduced the rates of biodegradation. It is …
Investigation Of Amphoteric Materials For Treatment Of Heavy Metals In Storm Water., Dingfang Liu
Investigation Of Amphoteric Materials For Treatment Of Heavy Metals In Storm Water., Dingfang Liu
LSU Historical Dissertations and Theses
Urban storm water runoff mobilizes and transports significant loads of heavy metals. Promulgation of NPDES Phase II regulations has spurred development of Best Management Practices (BMPs) for in-situ control of heavy metals. In this study, Amphoteric materials such as manganese oxides and iron oxides on the various substrates including silica sands, polymeric beads and cementitious particles were investigated. Surface characterization results indicated that oxide coatings ranged from 20 to 200-mum in depth, and surface areas were significantly increased by greater than a factor of one thousand compared to uncoated media. Point of zero charge (PZC) for manganese oxide coated media …
A Neural Network Approach To Dependent *Reliability Estimation., Roya Javadpour
A Neural Network Approach To Dependent *Reliability Estimation., Roya Javadpour
LSU Historical Dissertations and Theses
This research presents the creation of a new model for automating the generation of component and system reliability estimates from simulated field data for tightly coupled systems. The model utilizes the CMAC neural network architecture, which resembles the human cerebellum and is capable of approximating nonlinear functions. An analysis and testing of the network as a tool for reliability prediction of dependent components within an assembly has been performed. In order to evaluate the performance of the model, the network has been tested on simulated data and provided over 90% performance accuracy in learning non-linear functions that represent the dependency …
Ergonomic Evaluation Of Manually Operated Valves., Eileen Bordelon Hoff
Ergonomic Evaluation Of Manually Operated Valves., Eileen Bordelon Hoff
LSU Historical Dissertations and Theses
Due to the large number of facilities that produce oil and gas with numerous valves used, a review of valve handwheel operation was of interest. Review of literature on two handed handwheel tasks yielded very little and raised questions about what amount of torque a user could exert on a handwheel. The objectives of this research were to determine the effects of height of exertion, orientation of the handwheel and type of handwheel while making two-handed torque exertions, test a custom designed handwheel against commonly distributed handwheels and to determine the effects of gloves commonly used in the oil and …
Non -Intrusive Characterization Of A Dispersed, Bubbly, Axisymmetric Jet., Kevin Nathaniel Stanley
Non -Intrusive Characterization Of A Dispersed, Bubbly, Axisymmetric Jet., Kevin Nathaniel Stanley
LSU Historical Dissertations and Theses
This study investigated the effects of bubble size and phase distribution on the liquid and bubble flow fields in a dispersed, bubbly axisymmetric jet. Of primary interest was the interaction of the bubbles with large-scale structures in the developing region of the jet. Measurements were made non-intrusively via Laser Doppler Velocimetry (LDV), Phase-Doppler Analysis (PDA) and video imaging techniques. Liquid Reynolds' numbers were varied from approximately 6,000 to 18,000 while gas volume fraction ranged from 0 to 3%. Bubble sizes varied from approximately 600 mum to 1500 mum. Axial mean velocities and RMS fluctuations have been reported for the liquid …
Advanced Oxidation Processes For Remediation Of Explosives -Contaminated Soils., Elizabeth Covington Fleming
Advanced Oxidation Processes For Remediation Of Explosives -Contaminated Soils., Elizabeth Covington Fleming
LSU Historical Dissertations and Theses
Explosives contamination in soils is an environmental concern for the public due to their toxic effects. The United States Department of Defense (DoD) is particularly concerned with explosives contamination in soils due to the thousands of sites for which it is responsible for remediating. To date, the most common technology utilized for remediating explosives contamination in soils has been incineration. However, costs for incineration have been estimated to range from approximately $250 to $3250 per ton and are generally inversely related to the volume of soil. The use of advanced oxidation processes (AOPs), including dark and illuminated forms, was evaluated …
Water Quality Model For Evaluation Of Nonpoint Source Impacts Of Rice Field Runoff., Elizabeth Deette Smythe
Water Quality Model For Evaluation Of Nonpoint Source Impacts Of Rice Field Runoff., Elizabeth Deette Smythe
LSU Historical Dissertations and Theses
Water quality impairment in many water bodies in the state of Louisiana is attributed to agricultural nonpoint sources of pollution. Many of these use-impaired streams have also been hydromodified to facilitate agricultural development, deepening and straightening the channels to form "stretch lakes". This dissertation evaluated the unique, and previously uncharacterized and unquantified ricefield loadings and their impacts on these dystrophic waterbodies in order to provide the Louisiana Department of Environmental Quality (LDEQ) with assessments of stream impacts from implementing altered cropping practices known as "best management practices" (BMPs). In order to produce an assessment of rice BMPs, this dissertation developed …
Hydrodynamic Behavior Of Spouted Beds With Application To The Coating Of Heart Valve Components., Hao Jiang
Hydrodynamic Behavior Of Spouted Beds With Application To The Coating Of Heart Valve Components., Hao Jiang
LSU Historical Dissertations and Theses
Gas-solid fluidization is a subject having wide engineering applications overlapping different industries. A relatively unique application of fluidized bed technology resulted from a convergence of medical studies of thromboresistant materials with engineering development of gas impermeable and corrosion resistant coatings for artificial heart valves. The objective of this research was to study, through experimental measurements, gas-particle hydrodynamic behavior in the spouted bed, with an emphasis on biomedical manufacturing of prosthetic heart valves. Laboratory-scale and pilot-scale experiments were conducted to investigate the gas and solid phase behavior, such as minimum spouting velocity, pressure profile, particle velocity profile and particle density distribution. …
Modeling Escherichia Coli Concentration In Surface Runoff: The Ecoli Model., Teck Yee Ling
Modeling Escherichia Coli Concentration In Surface Runoff: The Ecoli Model., Teck Yee Ling
LSU Historical Dissertations and Theses
A biological model, ECOLI, is developed that is capable of continuously simulating E. coli concentration in surface runoff from agricultural land applied with manure. The model was calibrated and validated by using data from field-scale studies at Franklinton, Louisiana. During validation the model was interfaced with GLEAMS-SWT model to obtain the necessary hydrologic and erosion variables as input to the ECOLI model. The ECOLI model was found to perform best when simulating runoff concentration following the first application of waste. For reapplication of waste within 50 days, the trend of decrease over time was well-simulated but simulated E. coli concentrations …
An Intelligent Failure Analysis System., Claude Ray Mount
An Intelligent Failure Analysis System., Claude Ray Mount
LSU Historical Dissertations and Theses
The investigation of commercial/industrial failures is a vital, but complex task. This paper presents an Intelligent Failure Analysis System (aIFAS). It is a system designed by a failure analyst with the goal of making failure investigation easier. The knowledge base for aIFAS comes from commercial laboratory reports. The methodologies employed represents the experience gained from over five years of development. One goal of aIFAS is to provide a case-based expert system tool to help find answers. Functionality ranges from matching a new case to stored example cases to extracting relational data from the aIFAS knowledge base. This study focuses on …
Manipulations Of Natural System Functions Within The Mississippi Delta: A Simulation-Modeling Study., Jay Franklin Martin
Manipulations Of Natural System Functions Within The Mississippi Delta: A Simulation-Modeling Study., Jay Franklin Martin
LSU Historical Dissertations and Theses
This dissertation uses two estuarine spatial models and energy analysis of two river diversions within the Mississippi Delta to test the hypothesis that natural river inputs maximize marsh coverage and have net societal benefits. Substantial advancements including a higher resolution, variable time-step hydrodynamic module, a mass-balance sediment component, and a marsh colonization routine, distinguished the Mississippi Deltas Model (MDM) from the Barataria-Terrebonne Landscape Simulation Model (BTELSS). These advancements made the MDM capable of simulating the progradation of river deltas with varying river regimes. No Action Plans (NAP), simulated by both models, were used as a baseline of comparison for simulations …
Consumers' Reasoned Behavior Toward American Alligator Leather Products., Yingjiao Xu
Consumers' Reasoned Behavior Toward American Alligator Leather Products., Yingjiao Xu
LSU Historical Dissertations and Theses
This study determined consumers' perception of and attitude toward American alligator leather products and evaluated factors affecting consumers' purchase intention of the products. The Fishbein and Ajzen (1975, 1980) theory of reasoned behavior served as the theoretical framework for the study. The influence of six variables on purchase intention was measured: attitude toward purchase based on product attributes, subjective norm with respect to purchase, traditional attitude toward fashion products (fashion involvement), personality traits (self-confidence and self-consciousness), price perception (price-quality schema and prestige sensitivity), and demographics. The correlation between consumers' usage of media for fashion information and purchase intention was also …
Evaporative Mass Transfer Of Hydrophobic Organic Compounds From Exposed Contaminated Sediment And Dredged Materials., Raghunathan Ravikrishna
Evaporative Mass Transfer Of Hydrophobic Organic Compounds From Exposed Contaminated Sediment And Dredged Materials., Raghunathan Ravikrishna
LSU Historical Dissertations and Theses
Dredged sediment materials stored in confined disposal facilities (CDF) contain several hydrophobic organic compounds (HOC) such as polynuclear aromatic hydrocarbons (PAH), some of which are suspected carcinogens. The primary objective of this study was to evaluate the volatilization of HOCs from contaminated, exposed sediment dredged materials and contribute to the risk assessment framework being developed by the U.S. Army Corps of Engineers. Laboratory experiments were performed to measure HOC tracer emissions to air from contaminated sediments (laboratory inoculated and field aged) placed in a specially designed flux chamber. Flux was influenced by a number of factors such as relative humidity …
Component Reliability Estimation From Partially Masked And Censored System Life Data Under Competing Risks., Rudi Hendricus Petrus Martinus Arts
Component Reliability Estimation From Partially Masked And Censored System Life Data Under Competing Risks., Rudi Hendricus Petrus Martinus Arts
LSU Historical Dissertations and Theses
This research presents new approaches to the estimation of component reliability distribution parameters from partially masked and/or censored system life data. Such data are common in continuous production environments. The methods were tested on Monte Carlo simulated data and compared to the only alternative suggested in literature. This alternative did not converge on many masked datasets. The new methods produce accurate parameter estimates, particularly at low masking levels. They show little bias. One method ignores masked data and treats them as censored observations. It works well if at least 2 known-cause failures of each component type have been observed and …
Response Of Granular Layers In Flexible Pavements Subjected To Aircraft Loads., Donald Mark Smith
Response Of Granular Layers In Flexible Pavements Subjected To Aircraft Loads., Donald Mark Smith
LSU Historical Dissertations and Theses
Airfield pavement design is a complex blend of relatively simple linear elastic theory, fatigue concepts, correlations with small and full-scale tests, and pragmatic adjustments to reflect observations of in-service pavements. The granular base and subbase have always posed the most difficult analytical problem in traditional pavement design methodologies. For this reason, the granular layers have never been treated explicitly in design as have the asphalt concrete (AC) layer and subgrade layer, which have used predictive models for cracking in the AC and rutting in the subgrade as a function of linear-elastic strain and material properties. Instead, these granular layers were …
Development And Evaluation Of A Mass Spectrometer -Based Continuous Emission Monitor For Organic Compound Emissions From Combustion Devices., Emmanuel Tijani Wada
Development And Evaluation Of A Mass Spectrometer -Based Continuous Emission Monitor For Organic Compound Emissions From Combustion Devices., Emmanuel Tijani Wada
LSU Historical Dissertations and Theses
The Mass Spectrometer-based Continuous Emission Monitor (MS-CEM) for organic compounds was developed and evaluated at the Louisiana State University (LSU) Pilot-Scale Rotary Kiln Incinerator (RKI). The MS-CEM consists of stack probe, heat traced sampling line, vacuum pump, particulate filter, Nafion dryer and Extrel mass spectrometer. The Nafion dryer is a special type of dryer that has the ability to remove moisture from the gas sample without removing organic compounds of interest. The mass spectrometer is a quadrupole mass filter. The mass spectrometer includes a computer that controls and optimizes the operation of the unit. The MS-CEM was tested by injecting …
Effects Of Microstructure And Crystallographic Texture On Yield Behavior Of Aluminum-Copper-Lithium 2195 Plate., Karen Elizabeth Crosby
Effects Of Microstructure And Crystallographic Texture On Yield Behavior Of Aluminum-Copper-Lithium 2195 Plate., Karen Elizabeth Crosby
LSU Historical Dissertations and Theses
The focus of this research is to study the effects of deformation and aging on the yield behavior of precipitation-hardened Al-Cu-Li alloys, specifically AI-Cu-Li 2195 plate. Al-Cu-Li 2195 is a relatively new and exceptionally strong, yet lightweight aluminum alloy. Experimental methods applicable to mechanical/structural engineering and materials science problems provide the means for understanding the interrelation of deformation, microstructure, and crystal orientation (texture) as they affect the mechanical properties of crystalline materials. Yield strength is a vital mechanical property in that it defines the boundary of stress that may be applied to a part before a permanent, in some cases, …
Theoretical And Experimental Studies Of Flame -Generated Agglomerates Using Light Scattering., Guocai Shu
Theoretical And Experimental Studies Of Flame -Generated Agglomerates Using Light Scattering., Guocai Shu
LSU Historical Dissertations and Theses
Knowledge of optical properties and morphological characteristics of aggregated aerosols is important for pollution control, material synthesis through the aerosol route, oxidation of particulate matters, as well as understanding the mechanism of particulate formation and growth. However, the limitations of current light scattering theories as well as the lack of robust data inversion schemes render the complete characterization of the agglomerated structures difficult and time consuming. The objective of present work is to develop robust experimental and theoretical methods to characterize the aggregated aerosols from in-situ classical light scattering (CLS) as well as dynamic light scattering (DLS) measurements. In the …