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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 …
Channel Modeling And Resource Allocation In Ofdm Systems, Xiang Gao
Channel Modeling And Resource Allocation In Ofdm Systems, Xiang Gao
LSU Doctoral Dissertations
The increasing demand for high data rate in wireless communication systems gives rise to broadband communication systems. The radio channel is plagued by multipath propagation, which causes frequency-selective fading in broadband signals. Orthogonal Frequency-Division Multiplexing (OFDM) is a modulation scheme specifically designed to facilitate high-speed data transmission over frequency-selective fading channels. The problem of channel modeling in the frequency domain is first investigated for the wideband and ultra wideband wireless channels. The channel is converted into an equivalent discrete channel by uniformly sampling the continuous channel frequency response (CFR), which results in a discrete CFR. A necessary and sufficient condition …
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 …
Comparative Study On Double-Rotor Pm Brushless Motors With Cylindrical And Disc Type Slot-Less Stator, Pavani Gottipati
Comparative Study On Double-Rotor Pm Brushless Motors With Cylindrical And Disc Type Slot-Less Stator, Pavani Gottipati
LSU Master's Theses
Among brushless permanent magnet machines, the torus motors (also called Axial Flux Double-Rotor Permanent Magnet (AFTR PM) motors) are most compact and highly efficient. A cylindrical counterpart of this motor is a newly proposed Radial Flux Double-Rotor Permanent Magnet (RFTR PM) motor. The objectives of this thesis are to optimize the magnetic circuit of both AFTR PM and RFTR PM motors and to compare their electromechanical parameters on the basis of the results obtained from magnetic field simulation using Finite Element Method (FEM). To reach these objectives, FEM models are developed for both the motors, for particular given data. Applying …
A Collaborative High Performance And Grid Computing Portal, Prathyusha Akunuri-Venkata
A Collaborative High Performance And Grid Computing Portal, Prathyusha Akunuri-Venkata
LSU Master's Theses
The world of high performance and grid computing is so vast that it always poses constant challenges and high learning curves to researchers and scientists. A Portal-based solution facilitates a simple web-based graphical user interface that helps the non computer science users take advantage of highly evolving, on-demand, distributed computing to carry out their research activities. A collaborative portal brings together various resources, applications and services under one roof and provides a single point of entry and access to the users. This thesis work endeavors to build a unique High Performance and Grid Computing Portal that combines two existing high …
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 …
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 - …
Micro Injection Fuel/Air Premixer/Combustion, Jian Zhang
Micro Injection Fuel/Air Premixer/Combustion, Jian Zhang
LSU Doctoral Dissertations
Lean premixed (LP) combustion has become the dominant industrial approach to reduce NOx emissions. Homogeneous mixing of lean fuel and air mixtures prevents the presence of undesirable localized regions of near-stoichiometric fuel/air mixtures, thereby allowing a reduction in thermal NOx. A new concept, a multi-point micro injection premixer, is presented in this dissertation. The multi-point micro injection premixer is a porous plate that provides a simple but extremely effective method to mix air and fuel. An array of fuel jets is injected in a direction perpendicular to the plane of the premixer plate into an oncoming counterflow stream of air. …
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 …
Readjustment Of A Regional Geodetic Leveling Network To Account For Temporally And Spatially Variable Vertical Displacement Of Benchmarks, Kurt Shinkle
LSU Doctoral Dissertations
This dissertation describes and analyzes the temporally and spatially non-linear nature of the vertical displacement of 1st order geodetic benchmarks in the lower Mississippi Valley and northern Gulf of Mexico coastal region. The least-squares method of adjusting redundant surveying observations is implemented to compute the most likely value of the most recent rates of displacement at node benchmarks within the network, along with estimates of the uncertainty of those values. Using that result, a modification of the standard method of adjusting geodetic leveling networks is developed and demonstrated to compute new elevations for the node benchmarks which accounts for both …
A Novel Template Stage With Superior Alignment Capability For Nanoimprint And Step And Flash Lithography, Yunmi Jeon
A Novel Template Stage With Superior Alignment Capability For Nanoimprint And Step And Flash Lithography, Yunmi Jeon
LSU Master's Theses
The high-resolution capabilities of imprinting and step and flash lithography make these techniques strong contenders for the next generation lithography. Unfortunately, alignment remains an area of concern for nanoimprint because it must be completed before the template is moved into contact with the wafer. The large forces on the template during the process, even for step and flash, place additional demands on the stiffness as well as the reproducibility of the template stage. In this thesis, a prototype flexure stage has been developed to meet these demands. A compressive load, slightly below the Euler's limit, is used to produce relatively …
Biodegradation And Characterization Of A Bio-Based Polyester, Benjamin Edward Stevens
Biodegradation And Characterization Of A Bio-Based Polyester, Benjamin Edward Stevens
LSU Master's Theses
Anaerobic biodegradation in sewage sludge and aerobic biodegradation in compost of polyhydroxybutyrate (PHB) were investigated to determine degradation kinetics and identify changes in polymer properties. To determine the impact of a natural plasticizer on biodegradation, tributyl citrate (TBC) was blended with some test specimens. For comparison to another bioplastic, polylactic acid (PLA) was biodegraded in the anaerobic study. Evolved gaseous carbon was measured to assess biodegradability according to ASTM standards D5210 and D5338. Mass loss experiments were performed to facilitate determination of degradation kinetics. Melt-pressed plates of the bioplastic with five different initial mass-to-surface-area ratios (plate thicknesses of 0.24, 0.5, …
Production Data Analysis Of Shale Gas Reservoirs, Adam Michael Lewis
Production Data Analysis Of Shale Gas Reservoirs, Adam Michael Lewis
LSU Master's Theses
Hydrocarbon resources from unconventional shale gas reservoirs are becoming very important in the United States in recent years. Understanding the effects of adsorption on production data analysis will increase the effectiveness of reservoir management in these challenging environments. The use of an adjusted system compressibility proposed by Bumb and McKee (1988) is critical in this process. It allows for dimensional and dimensionless type curves to be corrected at a reasonably fundamental level, and it breaks the effects of adsorption into something that is relatively simple to understand. This coupled with a new form of material balance time that was originally …
Reactive Multilayer Foils And Their Applications In Joining, Xiaotun Qiu
Reactive Multilayer Foils And Their Applications In Joining, Xiaotun Qiu
LSU Master's Theses
In this study, Ni/Al multilayer foils were fabricated by a cold rolling method. A two-stage reaction process was observed in the reaction-ignition experiment. The phase formation process in the cold rolled foils was studied. The first reaction stage with a slow reaction velocity was the lateral growth of Al3Ni phase at isolated nucleation sites and the subsequent coalescence into a continuous layer. The second reaction stage with a fast reaction velocity was the growth of the Al3Ni layers in the direction normal to the Ni/Al interface until all Al was consumed. Afterwards, Al3Ni reacted with the remaining Ni to form …
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 …
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 …
Eigenvalue Optimization And Its Applications In Buckling And Vibration, Srinivas Gopal Krishna
Eigenvalue Optimization And Its Applications In Buckling And Vibration, Srinivas Gopal Krishna
LSU Doctoral Dissertations
Eigenvalue problems are of immense interest and play a pivotal role not only in many fields of engineering but also in pure and applied mathematics. An in-depth understanding of this class of problems is a pre-requisite for vibration and buckling analyses of structures. Design optimization of structures to prevent failure due to instability (bucking) and vibration introduces the problem of determining optimal physical parameters such that load carrying capacity or the fundamental natural frequency is maximized. A classical example of such problems is the Lagrange problem of determining the shape of the strongest column against buckling. The primary objective of …
Hydrodynamic Modeling Of A Hypothetical River Diversion Near Empire, Louisiana, Nathan Lamont Dill
Hydrodynamic Modeling Of A Hypothetical River Diversion Near Empire, Louisiana, Nathan Lamont Dill
LSU Master's Theses
Hydrodynamic models of a hypothetical Mississippi river diversion near Empire, LA are constructed using two popular finite element codes RMA2 and ADCIRC. In a series of simulations eddy viscosity parameters and bottom friction parameters are varied. Constant boundary conditions, discharge inflow and elevation outflow, are applied and water surface elevation and velocity solutions at fully developed flow are taken as steady-state results. A particle tracking code is developed and applied to the velocity solutions to aid in flow field comparisons. The results elucidate the model sensitivities to the varied parameters, and also provide for a comparison of the two different …
Photo-Control Of Antisense Activity In Cell Culture Using Caged Oligodeoxynucleotides, Mindi Huguet Faubion
Photo-Control Of Antisense Activity In Cell Culture Using Caged Oligodeoxynucleotides, Mindi Huguet Faubion
LSU Master's Theses
Antisense oligodeoxynucleotides (AS ODNs) are short single-stranded pieces of DNA that are designed to hybridize with messenger RNA and thus offer a powerful technique for controlling gene expression. Phosphorothioate AS ODNs are a well-established modification of the traditional phosphodiester structure that increase the in vitro half-life of AS ODN activity. In this work, we describe a method for controlling the hybridization activity of PS ODNs in cell culture with a photo-reversible mechanism. The influence of a photocaging compound, 1-(4,5-dimethoxy-2-nitrophenyl)diazoethane (DMNPE) on hybridization of ISIS 2302, a 20-mer PS ODN, was modeled using a molecular beacon assay. Based on this model, …
Effects Of Capping On Biodegradation Of Organic Contaminants In Sediments, Eun Ju Lee
Effects Of Capping On Biodegradation Of Organic Contaminants In Sediments, Eun Ju Lee
LSU Doctoral Dissertations
Sediment capping remains an effective remediation technique for contaminated sediments due to its capability to contain contaminants and provide a sound habitat for indigenous biota. This research investigated the effect of capping on biodegradation of organic contaminants in Anacostia River sediments using both experimental and modeling techniques. 14C–Phenanthrene mineralization was monitored under various redox conditions in Anacostia River sediments. Mineralization of 14C–phenanthrene was strongly linked to sulfate reduction, which was the more energetic process than any other anaerobic condition in Anacostia sediments. Sulfate is a more promising terminal electron acceptor for intrinsic degradation in Anacostia River and other PAH contaminated …
Evaluation Of Consolidation Parameters Of Cohesive Soils Using Pcpt Method, Rohit Raj Pant
Evaluation Of Consolidation Parameters Of Cohesive Soils Using Pcpt Method, Rohit Raj Pant
LSU Master's Theses
The piezocone penetration test (PCPT) has emerged as most widely used in situ method for obtaining soil profile as well as physical properties. The PCPT method provides three independent and nearby continuous measurements with the depth; they are: tip stress (qc), sleeve friction (fs) and pore pressure (u1, u2, or u3). These measurements have been successfully used to correlate various soil properties such as undrained shear strength, unit weight and consolidation parameters. This study presents the evaluation of the PCPT interpretation methods for their capability to reasonably estimate the consolidation parameters namely constrained modulus, overconsolidation ratio and vertical coefficient of …
Effect Of Hole Configurations On Film Cooling From Cylindrical Inclined Holes For The Application To Gas Turbine Blades, Yiping Lu
LSU Doctoral Dissertations
Film cooling is one of the cooling systems investigated for the application to gas turbine blades. Gas turbines use film cooling in addition to turbulated internal cooling to protect the blades outer surface from hot gases. The present study concentrates on the experimental and numerical investigation of film cooling performance for a row of cylindrical holes in a modern turbine blade. The adiabatic film effectiveness and the heat transfer coefficient are determined experimentally on a flat plate downstream of a row of inclined different geometries hole exit by using a single test transient IR thermography technique. The focus of this …
Juvenile Crawfish (Procambarus Clarkii) Lc50 Mortality From South Louisiana Crude, Peanut And Mineral Oil, Okey Umejuru
Juvenile Crawfish (Procambarus Clarkii) Lc50 Mortality From South Louisiana Crude, Peanut And Mineral Oil, Okey Umejuru
LSU Master's Theses
Nearly every continent has species of crawfish that inhabit wetlands or are near coastal areas where petroleum and other oils are produced, transported, and accidentally released. Most crawfish cannot tolerate polluted water. Thus, they could serve as biomonitors of fossil fuel, biofuel, and other oil releases and assess potential negative impacts such oils have on wetland and coastal ecosystems. The objectives of this study were to estimate the acute toxicity of three oils to juvenile crawfish and determine if toxicity was due to poisoning or interference with oxygen transfer across the gills. Juvenile crawfish (Procambarus clarkii) were tested for acute …
Locally Derived Nonpoint Loading Estimates For The Boeuf River/Bayou Lafourche Watershed, Emerald Purser Roider
Locally Derived Nonpoint Loading Estimates For The Boeuf River/Bayou Lafourche Watershed, Emerald Purser Roider
LSU Doctoral Dissertations
There is currently a great demand for data and models that can be used to quantify nonpoint source pollutant loads from different land-use types. The Louisiana Department of Environmental Quality (LDEQ) is in the process of implementing management programs for impacted water bodies based on the Total Maximum Daily Load (TMDL) of a pollutant. Pollutants of concern include total suspended solids (TSS), nitrogen, and phosphorus. One of the key parameters in determining the TMDL of a water body is the nonpoint source pollutant load from different land-use types. To date, such load estimates in Louisiana are lacking. The primary objective …
Computer-Aided Weld Inspection By Fuzzy Modeling With Selected Features, Sean Najm Ghazavi
Computer-Aided Weld Inspection By Fuzzy Modeling With Selected Features, Sean Najm Ghazavi
LSU Master's Theses
This thesis develops a computer-aided weld inspection methodology based on fuzzy modeling with selected features. The proposed methodology employs several filter feature selection methods for selecting input variables and then builds fuzzy models with the selected features. Our fuzzy modeling method is based on a fuzzy c-means (FCM) variant for the generation of fuzzy terms sets. The implemented FCM variant differs from the original FCM method in two aspects: (1) the two end terms take the maximum and minimum domain values as their centers, and (2) all fuzzy terms are forced to be convex. The optimal number of terms and …
Level Basin Approaches To Improve Water Management In Surface Irrigation For Northeast Louisiana, Luis R. Ocampo Briceno
Level Basin Approaches To Improve Water Management In Surface Irrigation For Northeast Louisiana, Luis R. Ocampo Briceno
LSU Master's Theses
In the state of Louisiana surface irrigation is widely used due to the low start-up cost, typically high rainfall, and soil conditions. Irrigation scheduling is an important practice to achieve water use efficiency in agriculture. The objectives of this study were to compare three different methods to determine crop evapotranspiration (ETc) for soybeans in addition to, evaluate a computer based irrigation scheduling program using real scale fields. Weather variables, soil moisture and irrigation water use collected during the summer months of 2005 and 2006 at a production agriculture farm in northeast Louisiana were studied. The ETc estimates obtained using atmometers …
Studies On The Heat/Mass Transfer Characteristics And Fluid Structure In A Square Internal Cooling Channel With Dimpled Surfaces, Fuguo Zhou
LSU Master's Theses
Experimental and numerical studies of heat/mass transfer on the dimpled surfaces in square channels are performed. The naphthalene sublimation method is employed in the experimental study. First, in a two-passage rotating channel, circle dimple matrices are cast on the leading and trailing walls in both the inlet and outlet of the serpentine channel. The experiments are carried out with Reynolds number of 7,000 and 21,000, and with Rotation number of 0 and 0.2. The dimpled walls lead to heat/mass transfer enhancements over smooth surfaces both in the stationary case and in the rotating case. In the stationary case, the dimple …