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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 …
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, …
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 …
Optimization For Software Release And Crash, Tanvir Khan
Optimization For Software Release And Crash, Tanvir Khan
LSU Master's Theses
Software testing is a process to detect faults in the completeness and quality of developed computer software. Testing is a key process in assuring quality by identifying defects in software, and possibly fixing them, before it is delivered to end-users. A major decision to make during this software testing is, to determine whether to continue testing and eventually releasing the software, or when to stop the test and ‘crash’ it. Such a decision needs to be made to optimally balance the tradeoff between the cost of development and the reliability of the software. In this paper, a new optimal strategy …
Evaluation Of Shear Strength Parameters Of Shale And Siltstone Using Single Point Cutter Tests, Mahendra Shewalla
Evaluation Of Shear Strength Parameters Of Shale And Siltstone Using Single Point Cutter Tests, Mahendra Shewalla
LSU Master's Theses
Detournay and Tan (2002) performed experiments with a rock cutting device to measure the load required to fail the rock under confining stress. They proposed models describing the correlation between the specific energy and confining stress for shear dilatant rocks as a function of unconfined specific energy at failure, cutter rake angle (θ), internal friction angle (φ) of the rock and an assumed interface friction angle (ψ) between the rock and the cutter. The aim of this research is to evaluate the model proposed by Detournay and Tan (2002), which states that specific energy varies linearly with bore hole pressure …
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 …
Engineering A Photo-Control Mechanism For Rna Interference, Richard Andrew Blidner
Engineering A Photo-Control Mechanism For Rna Interference, Richard Andrew Blidner
LSU Doctoral Dissertations
RNA interference (RNAi) is a phenomenon in which RNA molecules elicit potent and sequence-specific post-transcriptional gene silencing. Nucleic acid chemical modifications have been incorporated to improve their pharmacological properties. Despite numerous developments in chemical modifications for increased stability, safety, and efficiency of these therapeutic agents, they still face challenges of spatial and temporal targeting. One potential targeting strategy uses photocaging techniques, which involves the covalent attachment of photolabile compounds to the effector NA species that blocks bioactivity until exposed to near UV-light. This work demonstrates that fully-2’-fluorinated nucleic acids (FNAs) can elicit RNAi and that these effectors are resistant to …
Factors That Influence Visual Attention And Their Effects On Safety In Driving: An Eye Movement Tracking Approach, Larry Bargola Nabatilan
Factors That Influence Visual Attention And Their Effects On Safety In Driving: An Eye Movement Tracking Approach, Larry Bargola Nabatilan
LSU Doctoral Dissertations
Statistics show that a high percentage of road related accidents are due to factors that cause impaired driving. Since information extraction in driving is predominantly a visual task, visual distraction and its implications are therefore important safety issues. The main objective of this research is to study some of the implications of demands to human’s attention and perception and how it affects performance of tasks such as driving. Specifically, the study aims to determine the changes that occur in the visual behavior of drivers with different levels of driving experience by tracking the movement of the eye; examine the effects …
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 …
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 …
Differential Space Time Modulation And Demodulation For Time Varying Multiple Input Multiple Output Channels, Chetan Neginhal Chitnis
Differential Space Time Modulation And Demodulation For Time Varying Multiple Input Multiple Output Channels, Chetan Neginhal Chitnis
LSU Master's Theses
Over the last decade there has been considerable interest in wireless communication using multiple transmit and receive antennas. Several literatures exists that show that these multiple link support very high data rates with low error probabilities when the channel state information is available at the receiver. However when multiple antennas are employed or when the mobile environments change rapidly, it is not always possible to have apriori knowledge of the channel state matrices which calls for Differential Space-Time modulation techniques. Differential modulation is used in conjunction with Unitary Space-Time codes to evaluate their performance over time varying channels. Jakes model …
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 - …
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 …
Computer Model Of Hybrid Compensator Of Fast Varying Loads, Veronica Bohorquez
Computer Model Of Hybrid Compensator Of Fast Varying Loads, Veronica Bohorquez
LSU Doctoral Dissertations
A computer model of the hybrid compensator of fast varying loads was developed in this dissertation. The computer model was implemented in MFC Visual C++ compiler version 6.0. The classification of fast varying loads and effects of their operation in distribution systems were described in this dissertation. The power properties of fast varying loads were expressed in terms of the Currents' Physical Components Theory. Therefore, the Currents' Physical Components Theory was applied to systems with non-periodic voltages and currents. The supply current of the fast varying loads was decomposed into the useful and the useless components using an algorithm based …
Particle And Dredge-Scale Kinetic Studies Of Hydrophobic Organic Chemical Desorption From Sediment, Justin Edward Birdwell
Particle And Dredge-Scale Kinetic Studies Of Hydrophobic Organic Chemical Desorption From Sediment, Justin Edward Birdwell
LSU Doctoral Dissertations
The discharge of hydrophobic organic chemicals (HOCs) and other hazardous substances from anthropogenic sources to surface waters and the atmosphere has led to the widespread contamination of bottom sediments throughout the world. HOCs collect in sediments due to their affinity for organic matter and other sorbents present on and within their solid matrices. There is interest in the movement of HOCs from historically contaminated, resuspended sediments to surface waters due to the connection between chemical desorption and bioavailability. Quantitatively accurate predictions of contaminant concentrations in environmental media are needed for reliable risk assessment and to develop strategies for protection of …
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. …
Pile Capacity Utilization For Bridge Bents Designed Using Simplified Procedures, Md Rubiat Ferdous
Pile Capacity Utilization For Bridge Bents Designed Using Simplified Procedures, Md Rubiat Ferdous
LSU Master's Theses
Bent substructure systems are being used increasingly in bridge construction. Among the various bent systems, pile bents are considered a popular choice due to their effectiveness in reducing time and cost. They are constructed by first driving piles to a specified elevation above the ground surface. Then, a cast-in-place reinforced concrete bent cap ties the piles together at their top end. The current Louisiana Department of Transportation and Development Bridge Design Manual provides guidelines for the structural analysis and construction details for general use in the preparation of plans for pile bents. The manual allows the use of a simplified …
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 …
Simulation Study Evaluating Alternative Initial Responses To Formation Fluid Influx During Managed Pressure Drilling, Asis Kumar Das
Simulation Study Evaluating Alternative Initial Responses To Formation Fluid Influx During Managed Pressure Drilling, Asis Kumar Das
LSU Master's Theses
Managed pressure drilling is an innovative technique to precisely manage wellbore pressure. It is particularly applicable for reducing the risk of a kick or lost returns when drilling with a narrow window between pore pressure and fracture pressure. The constant bottomhole pressure method of managed pressure drilling uses annular frictional pressure and choke pressure in addition to mud hydrostatic pressure to achieve precise wellbore pressure control. This project investigated alternative initial responses to kicks to determine which would be most effective and reliable under different well scenarios when applying the constant bottomhole pressure method of managed pressure drilling. Three different …
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 …
Flow And Distribution Of Water In Fractional Wettability Unsaturated Porous Media, Zaydoun Turkey Abusalem
Flow And Distribution Of Water In Fractional Wettability Unsaturated Porous Media, Zaydoun Turkey Abusalem
LSU Doctoral Dissertations
In recent years, interest in fluid flow and transport in the unsaturated zone has gained more attention, due to growing concerns that the quality of the subsurface environment is adversely affected by agricultural, industrial, and municipal activities. The wettability properties (e.g., water repellency) of soil in the unsaturated zone play an important role in determining fluid movement and ultimate distributions. A number of studies have shown that preferential flow and spatially variable moisture content is likely to occur in water repellant soils. Development of appropriate constitutive relations for numerical modeling becomes even more difficult in systems that contain water repellant …
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 …
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 …
An Experimental Study On Characteristics And Behavior Of Reinforced Soil Foundation, Qiming Chen
An Experimental Study On Characteristics And Behavior Of Reinforced Soil Foundation, Qiming Chen
LSU Doctoral Dissertations
This research study aims at investigating the potential benefits of using the reinforcement to improve the bearing capacity and reduce the settlement of shallow foundations. To implement this objective, a total of one hundred seventeen tests were performed to study the behavior of reinforced soil foundation. The test results showed that the inclusion of reinforcement can significantly improve the soil's bearing capacity and reduce the footing settlement. The geogrids with higher tensile modulus performed better than geogrids with lower tensile modulus. The strain developed along the reinforcement is directly related to the settlement. The test results also showed that the …
Aconitic Acid From Sugarcane: Production And Industrial Application, Nicolas Javier Gil Zapata
Aconitic Acid From Sugarcane: Production And Industrial Application, Nicolas Javier Gil Zapata
LSU Doctoral Dissertations
Trans aconitic acid (TAA) is the predominant organic acid in cane leaf matter (CLM) juice. Its concentration is three to six times higher than the level found in sugarcane stalks. The variation of composition in terms of total fermentable sugars (TFS), anions, and cations of the LCP85-384 sugarcane variety during 2003-2006 seasons, as well as the ripener (Polado-L®) effect were analyzed. TAA content ranged between 2.1-3.1 kg / t CLM. The TFS in CLM juice yielded a fermentation efficiency of 92%, four points lower than with sugar molasses. Liquid-liquid extraction (LLE), solid-liquid extraction and ion exchange were evaluated for the …
Wind Loads For Petrochemical Structures, Samuel Amoroso
Wind Loads For Petrochemical Structures, Samuel Amoroso
LSU Doctoral Dissertations
Techniques currently available to practicing engineers for estimating wind loads for petrochemical structures have little theoretical or experimental basis. This dissertation research is an effort to expand the understanding of wind effects on petrochemical and other, similar structures. Petrochemical structures introduce geometric scales into wind tunnel model simulations below what are common for enclosed structures. Wind tunnel experiments were performed to help determine whether this will introduce problems in achieving dynamic similarity between models and prototypes. The experiments did not reveal any clear indication that petrochemical structures cannot be modeled in wind tunnels at scales similar to those used for …
Electrodeposition Of Rare Earth-Transition Metal Alloy Thin Films And Nanostructures, Rohit Mishra
Electrodeposition Of Rare Earth-Transition Metal Alloy Thin Films And Nanostructures, Rohit Mishra
LSU Doctoral Dissertations
Rare earth-transition metal alloys are of interest in MEMS and magnetic storage industries because of their unique magnetic properties. However, the applications of these alloys have been limited to bulk and thin film architectures because of the limitations of the contemporary vapor deposition technique to fabricate high aspect ratio nanostructures. The objective of this study is to develop an electrochemical process to deposit rare earth-transition metal alloys thus making it possible to deposit high aspect ratio nanostructures such as nanowires and nanotubes, which helps to tune their properties for specific applications. Electrodeposition of rare earth-transition metal alloys was achieved from …
Optimal Control Of Production And Distribution In A Supply Chain System Operating Under A Jit Delivery Policy, Pablo Biswas
Optimal Control Of Production And Distribution In A Supply Chain System Operating Under A Jit Delivery Policy, Pablo Biswas
LSU Doctoral Dissertations
This research deals with a supply chain system where the production or manufacturing facility operates under a just-in-time (JIT) environment, and the facility consists of raw material suppliers, manufacturers, and retailers where inventory of raw materials, work-in-process, and finished goods are involved, respectively. This work considers that the production of finished goods in one cycle starts just after the production or uptime in preceding cycle to minimize the idle time of the facility. Considering this scenario, inventory models are developed for different delivery situations: (a) perfect matching condition where no finished good remains after the shipments and (b) imperfect matching …