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LSU Master's Theses

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Articles 1291 - 1307 of 1307

Full-Text Articles in Engineering

Quantification Of The Spatial Gradient Of Local Volume Fraction From Tomography Images, Yongping Wang Jan 2002

Quantification Of The Spatial Gradient Of Local Volume Fraction From Tomography Images, Yongping Wang

LSU Master's Theses

Asphalt concrete has three constituents: aggregate, asphalt binder and air voids. In the mixture, aggregates serve as a skeleton of the mixture; asphalt serves as a binder to hold the aggregates together; and air voids prevent asphalt concrete from bleeding to avoid plastic mixes. The properties of asphalt concrete are controlled by the interaction of these three components. In asphalt concrete, asphalt binder, voids and aggregates are not uniformly distributed. The local volume fractions of these constituents vary with spatial locations. As a result, there exist a spatial gradient of the local volume fractions between two locations. Due to the …

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Computing Moments Of A Binary Horizontally/Vertically Convex Image Using Run-Time Reconfiguration, Cheowway Neoh Jan 2002

Computing Moments Of A Binary Horizontally/Vertically Convex Image Using Run-Time Reconfiguration, Cheowway Neoh

LSU Master's Theses

In this thesis, we present a design for computing moments of a binary horizontally/vertically convex image on an FPGA chip, using run-time reconfiguration. We compute the moments of up to third order for a total of 16 moments. We address how run-time reconfiguration speeds up moment computations without taking up huge hardware resources. Since we are considering a binary horizontally/vertically convex image, we look at an alternative method in moment computations that utilizes constant coefficient multipliers. We divide the image into segments and process one segment at a time. We reconfigure the constant coefficient multipliers before processing the next segment. …

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Bench-Scale Compost Reactors System And The Self-Heating Capabilities, Michael Alden Vining Jan 2002

Bench-Scale Compost Reactors System And The Self-Heating Capabilities, Michael Alden Vining

LSU Master's Theses

Less expensive bench-scale composting reactor systems which can mimic actual composting process via self-heating are needed. One can achieve such systems without using the expensive temperature feed-back control by properly insulating the bench composting reactors. However, the knowledge of heat generation and transfer in bench composting reactors is essential in properly designing such inexpensive insulation systems. All compost trial temperature profiles illustrated initial elevated temperature levels followed by a slow gradual temperature decreasing phase. Of all of the variables, the airflow rate, the volume and the overall heat transfer coefficient, seem to have the greatest impact on producing thermophilic temperatures. …

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Buckling Analysis Of Grid Stiffened Composite Structures, Samuel Kidane Jan 2002

Buckling Analysis Of Grid Stiffened Composite Structures, Samuel Kidane

LSU Master's Theses

Buckling of a stiffened composite cylinder is a very complex phenomenon that involves complex interactions between the skin and the stiffeners. Depending on different configurations of the skin and stiffener, different buckling failure modes and failure loads are observed in stiffened cylinders. In this work failure modes and buckling loads of stiffened composite cylinders under uniaxial loading condition is investigated by using analytical and experimental approaches. In the first Chapter an improved smeared method is developed to model the buckling problem of an isogird stiffened composite cylinder. In this model the stiffness contributions of the stiffeners is computed by analyzing …

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Offline And Online Variants Of The Traveling Salesman Problem, John Ebenezer Augustine Jan 2002

Offline And Online Variants Of The Traveling Salesman Problem, John Ebenezer Augustine

LSU Master's Theses

In this thesis, we study several well-motivated variants of the Traveling Salesman Problem (TSP). First, we consider makespan minimization for vehicle scheduling problems on trees with release and handling times. 2-approximation algorithms were known for several variants of the single vehicle problem on a path. A 3/2-approximation algorithm was known for the single vehicle problem on a path where there is a fixed starting point and the vehicle must return to the starting point upon completion. Karuno, Nagamochi and Ibaraki give a 2-approximation algorithm for the single vehicle problem on trees. We develop a Polynomial Time Approximation Scheme (PTAS) for …

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Enhanced Bioremediation Of 1,1,2,2-Tetrachloroethane In Wetland Soils, Jason S. House Jan 2002

Enhanced Bioremediation Of 1,1,2,2-Tetrachloroethane In Wetland Soils, Jason S. House

LSU Master's Theses

This research investigated the capability of wetland soils to function as a medium for the degradation of 1,1,2,2-TeCA and its daughter products, and the influence of different hydrogen donors and nutrients on this process. The rate constants calculated for this study, show that removal of 1,1,2,2-TeCA is occurring in the microcosms receiving hydrogen donors as well as the biotic controls. The parent compound was undergoing complete degradation to ethene, which was confirmed by ethene analysis, as well as monitoring the intermediate compounds. The analysis for the degradation products of 1,1,2,2-tetrachloroethene is important in determining the overall potential for successful degradation …

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Development Of A Magnetite Tracer Protocol For Seasonal Measurement Of Bed Sediment Biodiffusion Coefficients, Paul D. Libbers Jan 2002

Development Of A Magnetite Tracer Protocol For Seasonal Measurement Of Bed Sediment Biodiffusion Coefficients, Paul D. Libbers

LSU Master's Theses

This thesis describes the development of a particle tracer technique for making short-term, in situ measurements of aquatic bed sediment biodiffusion coefficients. The bioturbation process in the upper sediment layers of streams, lakes, estuaries, and the marine environment moves particles and porewater. When present, organic chemicals, metals, colloids, etc., are transported across these layers and exchanges may occur at the sediment-water interface. Fickian biodiffusion coefficients that characterize such particle movements, Db (cm2/yr), are used for assessing chemical diagenesis rates and contaminant fluxes and are specific to each site. Chemical Fate and Transport (CFaT) models, developed for tracking contaminants in aquatic …

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Tapered Liga Mold Insert, Ryan Anthony Turner Jan 2002

Tapered Liga Mold Insert, Ryan Anthony Turner

LSU Master's Theses

The applications of microstructures produced by the LIGA process are useful in a broad range of fields including: microfluidics, heat transfer, and mechanics. The Microsystems Engineering Team at Louisiana State University has used the LIGA process as a foundation for the team’s productivity in these areas. Many advances in the processes involved in producing these microstructures have been made in the past increasing the efficiency of the entire process. A modified exposure technique in the lithography stage of the LIGA process is being developed to produce microstructures with a draft angle as opposed to the standard straight walled structures. Electroformed …

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Surfactant-Induced Relative Permeability Modifications For Oil Recovery Enhancement, Subhash C. Ayirala Jan 2002

Surfactant-Induced Relative Permeability Modifications For Oil Recovery Enhancement, Subhash C. Ayirala

LSU Master's Theses

Surfactants have been considered for enhanced oil recovery by reduced oil-water interfacial tension. However, these surfactants may enhance oil recovery via wettability alteration as well. This study experimentally determines the influence of surfactant type and concentration on oil recovery, oil-water relative permeabilities and wettability in reservoir rocks. Several coreflood experiments were conducted using Yates reservoir fluids in Berea rocks and two types of surfactants (nonionic and anionic) in varying concentrations. A coreflood simulator was used to calculate oil-water relative permeabilities by history matching recovery and pressure drop measured during the corefloods. These relative permeability variations were interpreted using Craig's rules-of-thumb …

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Development Of A Phosphorus Management Model To Address Filamentous Algae In A Shallow, Subtropical, Urban Hypereutrophic Lake, Jennifer Eileen Ruley Jan 2002

Development Of A Phosphorus Management Model To Address Filamentous Algae In A Shallow, Subtropical, Urban Hypereutrophic Lake, Jennifer Eileen Ruley

LSU Master's Theses

City Park Lake is a shallow, subtropical, urban hypereutrophic lake located in Baton Rouge, Louisiana. By the late 1970’s, this artificial lake had experienced extreme eutrophication and suffered from frequent algal blooms and fish kills. Restoration of City Park Lake occurred in 1983 and consisted of dredging nutrient-laden sediments and the rehabilitation of sewage pipelines. Pre- and post-restoration water quality monitoring programs have provided valuable information by which to gage the long-term success of the restoration work. Following the restoration effort, dramatic improvements were observed in the lake including lower nitrogen, phosphorus and chlorophyll-a concentrations, reduced frequencies in algal blooms …

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Non-Linear Kinematic Hardening Model For Multiaxial Cyclic Plasticity, Marcio Costa Araujo Jan 2002

Non-Linear Kinematic Hardening Model For Multiaxial Cyclic Plasticity, Marcio Costa Araujo

LSU Master's Theses

A model of kinematic work hardening based on Frederick and Armstrong (1966), Phillips and Weng (1975), Chaboche (1979), and Voyiadjis and Basuroychowdhury (1998) is proposed for metal like behavior materials. In this proposed model, ratcheting is taken into account through the observation of the backstress evolution equation, modified by the addition of a new term, . Experimental observations made by Phillips and Lee (1979) showed that the direction of the movement of the center of the yield surface occurs in between the stress rate tensor and the plastic strain rate tensor directions. The new term, added to Chaboche model (1979), …

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Prediction Of Heat Transfer & Flow In Rotating Two-Pass Channels Connected By Holes., Achintya Kumar Pramanick Jan 2002

Prediction Of Heat Transfer & Flow In Rotating Two-Pass Channels Connected By Holes., Achintya Kumar Pramanick

LSU Master's Theses

A computational study of the effect of rotation on the velocity and thermal field for a two-pass channel connected by rows of holes on the divider wall has been conducted. Detailed velocity and Nusselt number distributions are presented inside the rotating two-pass coolant channel. The enhanced cooling in this passage design is achieved by a combination of impingement and crossflow-induced swirl. The cross flow is generated from one coolant passage to the adjoining coolant passage through a series holes placed along the dividing wall. The holes deliver the flow from one passage to another typically achieved in a conventional design …

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Polyurethane Foam Based Packing Media For Biofilters Removing Volatile Organic Compounds From Contaminated Air, Felipe A. Martinez Jan 2001

Polyurethane Foam Based Packing Media For Biofilters Removing Volatile Organic Compounds From Contaminated Air, Felipe A. Martinez

LSU Master's Theses

In recent years, biofiltration technology has gained acceptance worldwide as an economical and reliable air pollution control technology for treating gases contaminated by low concentrations of biodegradable volatile organic compounds (VOCs). Important applications include control of odors generated by wastewater treatment plants and control of VOC emissions from industrial sources. Although there have been many successful applications, several operational problems have been reported in the literature. These include difficulty in control over bed moisture content, high head loss caused by excessive biomass production, and inability to maintain removal efficiency during transient periods of high concentration loading. Use of a superior …

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Electrodeposition Of Niw Alloys Into Deep Recesses, Lakshmikanth Namburi Jan 2001

Electrodeposition Of Niw Alloys Into Deep Recesses, Lakshmikanth Namburi

LSU Master's Theses

Pulse electrodeposition has been investigated as a general technique for the electrodeposition of nickel-tungsten alloys in deep recesses for MEMS. Ni-W exhibits an induced codeposition mechanism, where the Ni reaction rate enhances the codeposition of W. Electrodeposition of this alloy has been achieved into recesses of 500 micron deep. The challenges that have been encountered are those related to gas evolving side reactions, local pH rises, diffusional limitations of the soluble species and long times required for filling the recesses. Electrodeposition on cylinder electrodes at different rotation rates was also carried out in order to obtain data on composition of …

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Multiple-Access Interference Suppression In Cdma Wireless Systems, Jianqiang He Jan 2001

Multiple-Access Interference Suppression In Cdma Wireless Systems, Jianqiang He

LSU Master's Theses

This thesis presents techniques that suppress the multiple access interference (MAI) in CDMA wireless systems. MAI is the main factor that influences the communication quality and the capacity in CDMA wireless systems. Hence the suppression of MAI is essential to the performance of a CDMA wireless system. For conventional CDMA systems where matched filters are used as receivers, the only MAI suppression method available is the power control, which allocates each user in the system an appropriate transmitter power level such that the transmitter power is minimized to decrease the MAI, while at the same time each user maintains a …

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Dynamic Scheduling, Allocation, And Compaction Scheme For Real-Time Tasks On Fpgas, Shobharani Tatineni Jan 2001

Dynamic Scheduling, Allocation, And Compaction Scheme For Real-Time Tasks On Fpgas, Shobharani Tatineni

LSU Master's Theses

Run-time reconfiguration (RTR) is a method of computing on reconfigurable logic, typically FPGAs, changing hardware configurations from phase to phase of a computation at run-time. Recent research has expanded from a focus on a single application at a time to encompass a view of the reconfigurable logic as a resource shared among multiple applications or users. In real-time system design, task deadlines play an important role. Real-time multi-tasking systems not only need to support sharing of the resources in space, but also need to guarantee execution of the tasks. At the operating system level, sharing logic gates, wires, and I/O …

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Simulation Study And Instability Of Adaptive Control, Zhongshan Wu Jan 2001

Simulation Study And Instability Of Adaptive Control, Zhongshan Wu

LSU Master's Theses

The Minimum-degree Pole Placement algorithm for Self-tuning Regulator design and the Recursive Least-square method and the projection algorithm for plant estimation are studied first in this thesis. Simulation studies for the estimator and controller algorithms are mainly undertaken after describing how to use MATLAB S-function in detail. Not only do Simulation experiments illustrates how and how well the MDPP and RLS algorithms work, but also show how to write and debug MATLAB codes for S-function programs. The robustness of the adaptive control system is intensively discussed subsequently. By using an estimator resistant to the noise contamination, the adaptive control system …

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