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Articles 1 - 30 of 89
Full-Text Articles in Engineering
The Electrodeposition Of Cerium/Copper Prox Catalysts On Metal Foam, James Matthew Faubion
The Electrodeposition Of Cerium/Copper Prox Catalysts On Metal Foam, James Matthew Faubion
LSU Master's Theses
A cerium/copper (Ce/Cu) preferred carbon monoxide (CO) oxidation (PROX) catalyst has been synthesized via electrodeposition onto a metal foam monolith. The catalyst was characterized using ICP, TPRS, TPR and SEM/EDS. Preliminary PROX TPRS evidence in a reaction mixture of 1% CO, 0.5% O2, 40% H2 (bal. Ar.) indicated that the highest activity was seen in a sequential deposition, in which Cu was deposited first. The highest CO oxidation activity was obtained when the Ce concentration in the second step was 0.1 M (resulting in a bulk wt% loading of 0.24 Ce:Cu). SEM/EDS analysis indicated that an increase in ceria loading …
Turbulence Modeling For Film Cooling Flows, Asif Hoda
Turbulence Modeling For Film Cooling Flows, Asif Hoda
LSU Doctoral Dissertations
An improved two equation turbulence model has been developed in this dissertation to better predict the complex film cooling flow field that is formed from the interaction of a coolant jet and a crossflow over a modeled turbine blade surface. Film cooling of turbine blades is commonly employed to effectively protect turbine blades from thermal failure and thereby to allow higher inlet temperatures in order to increase the efficiency of gas turbine engines. Film cooling involves the injection of rows of coolant jets from slots on the surface of a turbine blade which is then bent over by the crossflow …
Transcendental Eigenvalue Problems Associated With Vibration, Buckling And Control, Jayaram Subramanian
Transcendental Eigenvalue Problems Associated With Vibration, Buckling And Control, Jayaram Subramanian
LSU Master's Theses
The static and dynamic analysis of structures requires us to obtain solutions of their espective governing differential equations subject to appropriate boundary conditions. The dynamic analysis of non-uniform continuous structures is of primary interest, as most traditional methods take the help of discrete models to analyze them. Well established discrete model methods lead to an algebraic eigenvalue problem, the characteristic equation associated with which is a polynomial. The spectral characteristics of a continuous system nevertheless are represented by transcendental functions and cannot be approximated by polynomials efficiently. Hence finite dimensional discrete models are not capable of predicting the response of …
Semantic Image Retrieval Using Relevance Feedback And Transaction Logs, Amin Shah-Hosseini
Semantic Image Retrieval Using Relevance Feedback And Transaction Logs, Amin Shah-Hosseini
LSU Doctoral Dissertations
Due to the recent improvements in digital photography and storage capacity, storing large amounts of images has been made possible, and efficient means to retrieve images matching a user’s query are needed. Content-based Image Retrieval (CBIR) systems automatically extract image contents based on image features, i.e. color, texture, and shape. Relevance feedback methods are applied to CBIR to integrate users’ perceptions and reduce the gap between high-level image semantics and low-level image features. The precision of a CBIR system in retrieving semantically rich (complex) images is improved in this dissertation work by making advancements in three areas of a CBIR …
Development Of A Biomass Transducer For Automated Microalgal Bioreactors, Amar Shivaram Hegde
Development Of A Biomass Transducer For Automated Microalgal Bioreactors, Amar Shivaram Hegde
LSU Master's Theses
A highly sensitive miniaturized biomass transducer is necessary for continuous and reliable monitoring of the microalgal biomass in a computer controlled, automated microalgal bioreactor. Previous known methods to determine microalgal biomass applicable in these bioreactors are based on single wavelength turbidimetric or fluorescence. The objectives of this research were to (1) determine the light absorption characteristics of some commercially applicable microalgae in the electromagnetic wavelength range of 200-800 nm (2) design and construct a new miniaturized biomass transducer (3) process the transducer output to correlate with the biomass. Wavelength sensitivity analysis was conducted on the commercially important microalgal species - …
Electrodeposition Of Multilayered Nanostructures For Giant Magnetoresistance And Thermoelectric Applications, Despina Davis
Electrodeposition Of Multilayered Nanostructures For Giant Magnetoresistance And Thermoelectric Applications, Despina Davis
LSU Doctoral Dissertations
The electrodeposition of novel materials such as multilayer nanotubes for giant magneto resistance (GMR) applications and bismuth telluride nanotubes for thermoelectric applications are presented in this dissertation. The motivation for the multilayer electrodeposition is the investigation of giant magnetoresistance (GMR), a change in the material resistance in an applied magnetic field as a consequence of antiferromagnetic coupling. The nanowire high aspect ratio geometry allows the measurement of GMR with the current applied perpendicular to the plane (CPP) of the multilayers, which has been theoretically identified as being larger than the GMR in the (CIP) configuration (current in plane of multilayers). …
Three Dimensional Behavior Of Retaining Wall Systems, Kevin Abraham
Three Dimensional Behavior Of Retaining Wall Systems, Kevin Abraham
LSU Doctoral Dissertations
The objective of this study was to perform an engineering assessment of key three-dimensional (3-D) soil-structure interaction (SSI) features of selected earth retaining walls utilizing the nonlinear finite element method (FEM). These 3-D features are not explicitly incorporated in conventional two-dimensional (2-D) procedures that are commonly used to design these retaining walls. The research objective was accomplished utilizing the nonlinear FEM. The retaining walls selected for this research were described in detail. Design methodologies and computed responses for the walls based on conventional 2-D design procedures were summarized. Key engineering features of these structures such as construction sequence and system …
Production Well Operations Optimization In Water Distribution System Using Genetic Algorithm, Vineet Katiyar
Production Well Operations Optimization In Water Distribution System Using Genetic Algorithm, Vineet Katiyar
LSU Master's Theses
The City of Chandler, Arizona lies in semi-arid area and the water resources management has been a major concern by the State citizen. There is always a need of optimizing the available water resources when the rate of demand constantly beats the rate of replenishment. In this study we have developed a management model to link the Chandler water distribution model (EPANET) with the Chandler groundwater flow model (MODFLOW) under an optimization framework (Genetic algorithm). The EPANET model supplied by the Chandler city municipal authority has several improper setting (pumping schedules, valves settings, pressure zones etc.). The original model has …
Pre-Treatment Of Dynamically Varying Waste Gas Concentrations Using Activated Carbon Prior To Biofiltration: Effect Of Cycle Length On Degree Of Load Equalization, Kodi L. Collins
LSU Master's Theses
Dynamically varying waste gas concentrations pose challenges to the operation and design of air pollution control techniques such as biofilters. Although design approaches are becoming well established for biofilters treating gases containing VOC concentrations that are constant as a function of time, many industrial processes emit gas streams contaminated with volatile organic compounds at concentrations that fluctuate with time. Application of an effective load equalization technique could eliminate some challenges associated with fluctuating pollutant concentrations. Recent research has demonstrated that granular activated carbon (GAC) can serve as a passively controlled system to provide load-equalization as a pre-treatment prior to biofiltration. …
Measurements And Computations Of The Flow In Full-Scale Sugar Evaporative-Crystallizers And In Lab-Scale Models, Luis Fernando Echeverri
Measurements And Computations Of The Flow In Full-Scale Sugar Evaporative-Crystallizers And In Lab-Scale Models, Luis Fernando Echeverri
LSU Doctoral Dissertations
The circulation of massecuite is a key factor in achieving efficient heat transfer and crystallization in sugar evaporative crystallizers, and should be as high as practically possible for recovery, quality, and capacity reasons. This research report presents results on the circulation obtained applying modern experimental and numerical techniques. The main goals are contributing to expand the understanding of the process in sugar crystallizers; developing realistic models for the simulation of the circulation; and studying the effect of different design parameters. The circulation of massecuite is driven by buoyancy force due to density difference between the vapor generated and the surrounding …
Oblivious Transfer For Secure Communication, Abhishek Parakh
Oblivious Transfer For Secure Communication, Abhishek Parakh
LSU Master's Theses
Over the past four decades, computational power and algorithmic strategies have advanced tremendously resulting in an enormous increase in the key sizes required for secure cryptosystems such as RSA. At the same time, the electronic devices have grown smaller and portable requiring algorithms running on them to be optimized in size and efficiency while providing security, at least, equivalent to that provided on a typical desktop computer. As a result, the industry is moving towards newer cryptosystems such as ECC and NTRU that are well suited for resource constrained environments. While, ECC claims to provide security equivalent to that of …
Passive Alignment Of Micro-Fluidic Chips Using The Principle Of Elastic Averaging, Sitanshu Gurung
Passive Alignment Of Micro-Fluidic Chips Using The Principle Of Elastic Averaging, Sitanshu Gurung
LSU Master's Theses
This thesis presents a novel design for a passive alignment feature for vertically stacking chips in a micro fluidic device. Each chip is the size of a standard microscopic slide (75mm—25mm) and is a highly specialized functional unit designed and fabricated to process fluidic samples. The fluidic samples in the device flows from one chip to another using inter connecting holes 500μm-100μm in diameter. Hence an alignment of better than 100μm between chips is necessary to allow for the interconnecting holes to overlap so as to provide with a path for the fluid to flow. The feature to be used …
Monolithic Integration Of High-Aspect-Ratio Microstructures With Cmos Circuitry, Tinghui Xin
Monolithic Integration Of High-Aspect-Ratio Microstructures With Cmos Circuitry, Tinghui Xin
LSU Doctoral Dissertations
This work involves developing processing techniques for monolithically integrating a high-aspect-ratio microstructures with CMOS circuitry. A microsystem comprising of a microprobe array and signal processing circuitry is utilized as a test vehicle to demonstrate this fabrication process. One potential application of this microsystem is for recording neural signals from the central nervous system. The main results include thick photoresist processing, DC and pulse electroplating to form high-aspect-ratio microprobes, microprobe sharpening and developing a post-IC monolithic integration process. SU-8 is utilized for thick photoresist application. This work focuses on realization of a deep microrecess array in thick resists rather than traditional …
An Investigation Of The Frictional And Thermal Behavior Of Oscillatory Sliding Line Contacts, Mongi Mansouri
An Investigation Of The Frictional And Thermal Behavior Of Oscillatory Sliding Line Contacts, Mongi Mansouri
LSU Doctoral Dissertations
This research deals with an experimental and numerical investigation of the frictional and thermal behavior of pin-bushing pairs, operating at reciprocating sliding motion or under heavy loads. Large interfacial temperatures developed due to frictional heating can cause failure. Therefore, numerical prediction and analysis of the surface temperature under various operating conditions are important. Laboratory tests using a pin-bushing tester provided measurements of the friction coefficient and temperature. Hard coated and plain (uncoated) bushings, both made of induction hardened stainless steel, were tested. Lower coefficient of friction and surface temperature were observed in the case of the coated bushing. In the …
Study Of Demolding Process In Thermal Imprint Lithography Via Numerical Simulation And Experimental Approaches, Zhichao Song
Study Of Demolding Process In Thermal Imprint Lithography Via Numerical Simulation And Experimental Approaches, Zhichao Song
LSU Master's Theses
The objective of present study was to analyze the mechanical behavior of polymer resist during the demolding process, such as stress distribution and evolution; distortion and tilt of microstructures in thermal imprint lithography, a new emerging technique in mass production of micro/nanoscale patterns. One of the most challenging technical issues for thermal imprint lithography is the structural damages during demolding process. Thermal stress, adhesion force and friction force all play important roles in determination of the success of demolding and it is crucial to understand the underlying physics in order to optimize the structure and process design. In present study, …
Magnetically Induced Release Of Fluorescein Isothiocyanate (Fitc) From Polymer Nanoparticle Composites (Pncs), Michelle Urbina
Magnetically Induced Release Of Fluorescein Isothiocyanate (Fitc) From Polymer Nanoparticle Composites (Pncs), Michelle Urbina
LSU Master's Theses
Magnetically induced drug release can be used as a site-specific, minimally invasive pharmaceutical treatment. Its purpose is to increase the efficacy of drug therapies to diseased or damaged tissue and to decrease the amount of unnecessary damage to healthy, surrounding tissue. To prove the concept of drug release by a magnetic field, this study focused on the release of a fluorescent molecule from magnetic polymeric nanoparticle composites (PNCs) via induction of an alternating current (AC) magnetic field. Fluorescent magnetic PNCs used were 250 ?m or less in size, and were made of poly(methyl methacrylate) (PMMA) containing either the magnetic material …
Mechanistic Modeling Of An Underbalanced Drilling Operation Utilizing Supercritical Carbon Dioxide, Faisal Abdullah Aladwani
Mechanistic Modeling Of An Underbalanced Drilling Operation Utilizing Supercritical Carbon Dioxide, Faisal Abdullah Aladwani
LSU Doctoral Dissertations
Mechanistic modeling of an underbalanced drilling operation using carbon dioxide has been developed in this research. The use of carbon dioxide in an underbalanced drilling operation eliminates some of the operational difficulties that arises with gaseous drilling fluids, such as generating enough torque to run a downhole motor. The unique properties of CO2, both inside the drill pipe and in the annulus are shown in terms of optimizing the drilling operation by achieving a low bottomhole pressure window. Typically CO2 becomes supercritical inside the drill pipe at this high density; it will generate enough torque to run …
Experimental And Modeling Studies Of Contaminant Transport In Capped Sediments During Gas Bubble Ebullition, Qingzhong Yuan
Experimental And Modeling Studies Of Contaminant Transport In Capped Sediments During Gas Bubble Ebullition, Qingzhong Yuan
LSU Doctoral Dissertations
Fluxes of the three organics and eighteen metals from sediments were measured with diffusion chambers, and the effectiveness of a sand cap ascertained. The influence of sediment consolidation on contaminant flux and the mass transfer coefficient at the sediment-water interface was studied. A two-layer diffusion-advection model and consolidation model were coupled to elucidate the effect of sediment consolidation on chemical transport in the sediment-cap system. The model was tested and verified by the experimental data from microcosms, and then was used to predict phenanthrene flux under field conditions. The simulation results showed that consolidation could accelerate phenanthrene breakthrough and enhance …
Flow Field And Heat Transfer Analyses Of Mechanical Seals, Zhaogao Luan
Flow Field And Heat Transfer Analyses Of Mechanical Seals, Zhaogao Luan
LSU Doctoral Dissertations
Mechanical seals are widely used in rotating equipment such as pumps, turbines and agitators to prevent leakage. One crucial factor for keeping seals reliable is the thermal behavior of the seal rings. The existing literature on thermal effects in seals primarily concentrates on the conduction of heat into the rings. Yet, a more complete analysis requires understanding of the flow field around the rings. In this dissertation, both the laminar and turbulent flows within the seal chamber are studied and their effects on the heat transfer in the seal rings are evaluated. Based on extensive sets of numerical simulations, heat …
Characterization Of Polyethylene Glycol Hydrogels For Biomedical Applications, Anushree Datta
Characterization Of Polyethylene Glycol Hydrogels For Biomedical Applications, Anushree Datta
LSU Master's Theses
Polyethylene glycol is one of the most widely used synthetic materials for biomedical applications. Its biocompatibility, flexibility, and 'stealth' properties make it ideal for use in drug delivery applications. The main objective of this paper is to characterize the structural and mass transfer properties of polyethylene glycol hydrogels for applications in drug delivery and biological immobilization. Swelling behavior of the gels was studied to determine the mesh size, and other significant structural parameters of the gel. For accurate design of drug delivery device, along with network design, mathematical modeling of release profiles was performed. The study of PEG hydrogels was …
On The Stress Analysis Of Bimetallic Packing Rings, Eric Richard Lewis
On The Stress Analysis Of Bimetallic Packing Rings, Eric Richard Lewis
LSU Master's Theses
The purpose of this research is to try and understand hypercompressor packing ring failures better with a view of ultimately reducing or even eliminating their occurrences. In order to gain further understanding of packing ring failures, we seek to obtain an appreciation of the stresses they experience during operation. First we consider a conventional simulation of an axisymmetric packing ring and cup subjected to the typical pressure loading conditions experienced by these components when installed in a hypercompressor cylinder. The key locations of interest are along the bimaterial interface, and in particular at the ends of the interface. These ends …
Predictive Data Compression Using Adaptive Arithmetic Coding, Claudio Jose Iombo
Predictive Data Compression Using Adaptive Arithmetic Coding, Claudio Jose Iombo
LSU Master's Theses
The commonly used data compression techniques do not necessarily provide maximal compression and neither do they define the most efficient framework for transmission of data. In this thesis we investigate variants of the standard compression algorithms that use the strategy of partitioning of the data to be compressed. Doing so not only increases the compression ratio in many instances, it also reduces the maximum data block size for transmission. The partitioning of the data is made using a Markov model to predict if doing so would result in increased compression ratio. Experiments have been performed on text files comparing the …
Measurement Of Metal Migration In Sediment Caps With X-Ray Fluorescene, Ming Yin
Measurement Of Metal Migration In Sediment Caps With X-Ray Fluorescene, Ming Yin
LSU Doctoral Dissertations
ABSTRACT Sand is often used as a passive barrier to slow release of metals from the sediment and to separate benthic organisms from the sediment. Materials that effectively adsorb metals have the potential to provide significantly greater effectiveness by further retarding metal release. In this thesis, the effectiveness of apatite and Phosphil®, which contain phosphate in a form that can absorb many metals, is evaluated with a series of sorption and migration column experiments using Cr, Cu, Zn and Pb. Langmuir shape isotherms were observed suggesting that the effectiveness of these materials decreases at high concentration. The sorption isotherm experiments …
Characterization Of Unsaturated Soils Using Elastic And Electromagnetic Waves, Bashar Alramahi
Characterization Of Unsaturated Soils Using Elastic And Electromagnetic Waves, Bashar Alramahi
LSU Doctoral Dissertations
Recent advances in laboratory instruments and techniques enabled researchers to explore new aspects of the behavior of geomaterials and perform measurements that would be otherwise impossible to acquire using traditional geotechnical laboratory techniques. This dissertation is focused on utilizing elastic and electromagnetic wave measurements and SMCT imaging to non-destructively characterize different aspects of the behavior of unsaturated soils. A model that relates P-wave velocity in soils to the volumetric water content was used to develop a new methodology to determine the in situ density and moisture content of soils. It was numerically and experimentally verified to assess it validity and …
Granular Contact Lubrication: Theory And Experiment, Karim El Kholy
Granular Contact Lubrication: Theory And Experiment, Karim El Kholy
LSU Doctoral Dissertations
This dissertation is devoted to a theoretical and experimental study of the granular contact lubrication, both. The theory is based on the kinetic of the granular material where the granules interact with each other and with the boundary surfaces through instantaneous, binary collisions, characterized by a constant coefficient of restitution. Specifically this study focuses on granular lubrication in Couette flows. A series of simulations is reported and the results show good agreement with several published papers. Also, a theory that ties the true temperature to the grain mobility is developed. The true temperature of a granular material depends on the …
The Catalytic Partial Oxidation Of N-Tetradecane On Rh And Sr Substituted Pyrochlores, Daniel Haynes
The Catalytic Partial Oxidation Of N-Tetradecane On Rh And Sr Substituted Pyrochlores, Daniel Haynes
LSU Master's Theses
Catalyst deactivation by high levels of sulfur and aromatics limits the catalytic partial oxidation (CPOX) of diesel fuel into a H2-rich stream for fuel cells. These species poison traditional supported metal catalysts because they adsorb strongly to electron dense metal clusters and promote the formation of carbon on the surface. Therefore, it is logical to spatially distribute an active metal into the lattice of a chemically and thermally stable material to create an active catalyst surface that is less likely to accumulate carbon or be deactivated by sulfur. In this work, Rh metal only and Rh + Sr …
Development Of Micropump For Microfluidic Applications, Dong Eun Lee
Development Of Micropump For Microfluidic Applications, Dong Eun Lee
LSU Doctoral Dissertations
This dissertation covers the research work on two types of micropumps, one is based on magnetohydrodynamic (MHD) principle that utilizes Lorentz force for actuation, and the other is based on electrochemical actuation. The AC-type MHD micropump was designed and analyzed as a solution to the bubble formation problem encountered in DC-type MHD micropump. A UV-LIGA process using thick layer of SU-8 negative photoresist was successfully developed to microfabricate the AC MHD micropump. Preliminary studies and tests of the AC MHD micropumps demonstrate that bubble formation was significantly reduced to permit the proper function of the micropump. A continuous flow was …
A Liquid Lens Based On Electrowetting, Jihwan Park
A Liquid Lens Based On Electrowetting, Jihwan Park
LSU Master's Theses
A primary goal of this work is to develop and characterize a novel liquid lens based on electrowetting. A droplet of silicone oil confined in an aqueous solution works as a lens. Electrowetting then controls the shape of the confined silicone oil, and the focal length may be varied upon an applied electric potential. The planar lens design is employed for easy integration of a lens system into a microfluidic device. The achievements of this work are to develop an electrowetting-based planar liquid lens without an off-the-plane electrode structure and to demonstrate the planar liquid lens with variable focal length …
Study Of Half-Order Bod Reactions, Nicole Plauche Lirette
Study Of Half-Order Bod Reactions, Nicole Plauche Lirette
LSU Master's Theses
Appropriate modeling of Biochemical Oxygen Demand, BOD, is an important part of understanding the character of a wastewater. Much necessary information is gleaned and extracted from the kinetic equation chosen for modeling, especially when a BOD model is included in a dissolved oxygen model. Some information includes the ultimate level of BOD exerted, the rate the BOD demand for dissolved oxygen is exerted, and the critical time at which the minimum level of dissolved oxygen occurs. Although widely used, the first-order kinetic BOD model is not suited for all situations. In some instances, as is the case with constituents found …
Optimum Energy Allocation For Detection In Wireless Sensor Networks, Krishna Kishore Gunturu
Optimum Energy Allocation For Detection In Wireless Sensor Networks, Krishna Kishore Gunturu
LSU Master's Theses
The problem of binary hypothesis testing in a wireless sensor network is studied in the presence of noisy channels and for non-identical sensors. We have designed a mathematically tractable fusion rule for which optimal energy allocation for individual sensors can be achieved. In this thesis we considered two methods for transmitting the sensor observations; binary modulation and M-ary modulation. In binary modulation we are able to allocate the energy among the sensors and protect the individual quantized bits where as the M-ary modulation provides optimum energy allocation only among the sensors. The goal is to design a fusion rule and …