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2004

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Articles 2371 - 2400 of 2785

Full-Text Articles in Engineering

Route Planning Of Automated Guided Vehicles For Container Logistics, Sanjay Shankarrao Gurav Jan 2004

Route Planning Of Automated Guided Vehicles For Container Logistics, Sanjay Shankarrao Gurav

LSU Master's Theses

Automated guided vehicles (AGVs) are widely used in container terminals for the movement of material from shipping to the yard area and vice versa. Research in this area is directed toward the development of a path layout design and routing algorithms for container movement. The problem is to design a path layout and a routing algorithm that will route the AGVs along the bi-directional path so that the distance traveled will be minimized. This thesis presents a bi-directional path flow layout and a routing algorithm that guarantee conflict-free, shortest time routes for AGVs. Based on the path layout, a routing …

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Mesoscopic Simulation Of Abnormal Grain Growth, Rakesh Kumar Behera Jan 2004

Mesoscopic Simulation Of Abnormal Grain Growth, Rakesh Kumar Behera

LSU Master's Theses

Grain growth is the process that takes place during annealing of polycrystalline materials; its major feature is a systematic increase in grain size. Two different types of grain growth can be distinguished: the normal and abnormal grain growth. During normal grain growth, the microstructure exhibits a uniform increase in grain size with time and the grain size distribution follows the log-normal distribution with the grain sizes ranging from 0 - 2.2 times the average grain size (R). On the contrary, when the abnormal grain growth is the dominant mechanism, there are certain grains (abnormal grains) in the microstructure that grow …

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A Simplified Thermohydrodynamic Stability Analysis Of The Plain Cylindrical Hydrodynamic Journal Bearings, Sumit Singhal Jan 2004

A Simplified Thermohydrodynamic Stability Analysis Of The Plain Cylindrical Hydrodynamic Journal Bearings, Sumit Singhal

LSU Master's Theses

A journal bearing is used to support radial loads under high speed operating conditions. In a journal bearing, pressure or hydrodynamic lift is generated in the thin lubricant oil film that separates the shaft and the bushing, thus preventing metal-to-metal contact. Some journal-bearing configurations are susceptible to large-amplitude, lateral vibrations due to a “self-excited instability” known as oil whirl. In order to investigate the effects of lubricant viscosity on oil whirl, a simplified Thermohydrodynamic analysis (THD) analysis of a plain cylindrical journal bearing system has been developed. The “classical” form of the Reynolds equation coupled with simplified, first-order energy equations …

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First Order Sigma-Delta Modulator Of An Oversampling Adc Design In Cmos Using Floating Gate Mosfets, Syam Prasad Sbs Kommana Jan 2004

First Order Sigma-Delta Modulator Of An Oversampling Adc Design In Cmos Using Floating Gate Mosfets, Syam Prasad Sbs Kommana

LSU Master's Theses

We report a new architecture for a sigma-delta oversampling analog-to-digital converter (ADC) in which the first order modulator is realized using the floating gate MOSFETs at the input stage of an integrator and the comparator. The first order modulator is designed using an 8 MHz sampling clock frequency and implemented in a standard 1.5µm n-well CMOS process. The decimator is an off-chip sinc-filter and is programmed using the VERILOG and tested with Altera Flex EPF10K70RC240 FPGA board. The ADC gives an 8-bit resolution with a 65 kHz bandwidth.

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Scalability Of Car-Following And Lane-Changing Models In Microscopic Traffic Simulation Systems, Yan Zhang Jan 2004

Scalability Of Car-Following And Lane-Changing Models In Microscopic Traffic Simulation Systems, Yan Zhang

LSU Master's Theses

Microscopic simulation models are more and more widely used to support real-time control and management functions in the field of transportation engineering. However, even with today¡¯s advancement in computing power, microscopic simulation modeling remains a computationally intensive process that imposes limitations on its potential use for modeling large-scale transportation networks. While microscopic features of a simulated system collectively define the overall system characteristics, it is argued here that the simulation process itself is not necessarily free of redundancy which, if reduced, could substantially improve the computational efficiency of simulation processes without substantially compromising the overall integrity of the simulation process. …

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Impact Of Static Flexion Duration On The Development Of A Neuromuscular Disorder Of The Lumbar Spine, Rebecca Victoria Labry Jan 2004

Impact Of Static Flexion Duration On The Development Of A Neuromuscular Disorder Of The Lumbar Spine, Rebecca Victoria Labry

LSU Master's Theses

Many occupational groups work under adverse conditions in which their spinal columns are fully flexed under load for substantial periods of time. This study was designed to determine the response of the lumbar spine to a static load of a substantial duration under a range of load magnitudes. The impact of static loads of 20, 40 and 60N were applied over 30 min flexion, 10 min rest, and 30 min flexion (for a total of one hour exposure) followed by a 7 h rest. Lumbar viscoelastic creep (laxity) and reflex electromyographic (EMG) activity were monitored over both flexion periods and …

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Ultra Deep Su-8 Manufacturing And Characterization For Mems Applications, Charles Joseph Becnel Jan 2004

Ultra Deep Su-8 Manufacturing And Characterization For Mems Applications, Charles Joseph Becnel

LSU Master's Theses

The Micro Systems Engineering Team (mSET) at Louisiana State University (LSU) utilizes microfabrication for a number of heat and mass transfer devices. These include cross flow heat exchangers, mechanical seals with integrated micro heat exchangers, catalytic converters, and micro reactors. In all of these applications, micro honeycomb arrays provide increased surface area per unit volume which significantly enhances heat and mass transfer. In the past, it was only possible to fabricate SU-8 structures approximately 1.5 mm tall. Furthermore, qualitatively, it is much more difficult to fabricate close packed feature arrays than sparse arrays. For many of the previously mentioned applications, …

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Development And Integration Of New Processes Consuming Carbon Dioxide In Multi-Plant Chemical Production Complexes, Sudheer Indala Jan 2004

Development And Integration Of New Processes Consuming Carbon Dioxide In Multi-Plant Chemical Production Complexes, Sudheer Indala

LSU Master's Theses

New, energy-efficient and environmentally acceptable, catalytic processes have been identified that can use excess high purity CO2 as a raw material from the sources available in a chemical production complex. The chemical complex in the lower Mississippi River Corridor has been used to show how these new plants can be integrated into this existing infrastructure using the Chemical Complex and Cogeneration Analysis System. Eighty six published articles of laboratory and pilot plant experiments were reviewed that describe new methods and catalysts to use CO2 for producing commercially important products. Reactions have been categorized as hydrogenation reactions; hydrocarbon synthesis …

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Effect Of Ohmic Heating On Color, Rehydration And Textural Characteristics Of Fresh Carrot Cubes, Sandeep Dattatraya Bhale Jan 2004

Effect Of Ohmic Heating On Color, Rehydration And Textural Characteristics Of Fresh Carrot Cubes, Sandeep Dattatraya Bhale

LSU Master's Theses

Carrot cubes were ohmically heated with 2 different frequencies 1 Hz and 60 Hz to evaluate change in color, texture and rehydration properties. Carrot samples were stored under 4 different relative humidity (RH) conditions 11.1 %, 32.7%, 55.7 % and 75.3 %. Experiments were conducted to monitor the textural parameters of hardness, fracturability, adhesiveness, cohesiveness and chewiness and color changes in terms of CIE color values. Results showed that the hardness, fracturability and adhesiveness of 1- Hz samples stored at 75.3 % RH were different from those at 55.7 % RH. The adhesiveness, cohesiveness and chewiness of 1-Hz samples were …

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Development Of Resilient Modulus Prediction Models For Base And Subgrade Pavement Layers From In Situ Devices Test Results, Ravindra Gudishala Jan 2004

Development Of Resilient Modulus Prediction Models For Base And Subgrade Pavement Layers From In Situ Devices Test Results, Ravindra Gudishala

LSU Master's Theses

Currently, the design of flexible pavements is generally conducted based on static properties such as California Bearing Ratio and soil support value. These properties do not represent the actual response of the pavement layers under traffic loadings. Recognizing this deficiency, the current and the 2002 mechanistic –empirical guide for design of pavement structures recommended the use of resilient modulus for characterizing the base and subgrade soil and for the design of flexible pavements. The objective of this study was to develop models to estimate the resilient modulus of base and subgrade soils from in situ test devices. Two types of …

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A Re-Evaluation Of Geopressured-Geothermal Aquifers As An Energy Resource, Jeremy Scott Griggs Jan 2004

A Re-Evaluation Of Geopressured-Geothermal Aquifers As An Energy Resource, Jeremy Scott Griggs

LSU Master's Theses

The search for more efficient and economical forms of energy generation is a continual process. Natural gas production and electricity generation from geopressured-geothermal aquifers is an unconventional hydrocarbon source that has long been unproductive due to its marginal economics and lack of technological certainty. This thesis demonstrates that, based on modern technological competencies and economic constraints, geopressured-geothermal energy now maintains a viable future as an alternative domestic energy source.

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Online Heat Transfer Measurement And Analysis For Sugar Mill Evaporators, David Timothy Solberg Jan 2004

Online Heat Transfer Measurement And Analysis For Sugar Mill Evaporators, David Timothy Solberg

LSU Master's Theses

Fouling and scaling in evaporators has been an area of great interest to raw sugar mills for a number of years and many of the mechanisms causing the scale and the rates of scaling are unknown. In an attempt to quantify the scaling rates and measure the scaling, an online model has been developed to model a system of evaporators. Monitoring the heat transfer coefficient as a function of time enabled measurement of the scaling rate by monitoring the heat transfer coefficient as it decreased with time. It is assumed that the scaling on the juice side of the evaporators …

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Probabilistic Risk Assessment Method For Prioritization Of Risk Factors, Jay Tarakkumar Shah Jan 2004

Probabilistic Risk Assessment Method For Prioritization Of Risk Factors, Jay Tarakkumar Shah

LSU Master's Theses

Risk management involves assessing the risk sources and designing strategies and procedures to mitigate those risks to an acceptable level. Measurement of risk factors plays an important role in the assessment of risk. This research proposes to develop risk assessment frameworks and mathematical model (Probabilistic Risk Assessment model) identify the risk factors. Quantification and prioritization of risk factors will help to design controls, resource allocation policies and minimize the total cost using the Cost Minimization model. The proposed models are applied to a complex system that is representative of actual business situations.

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Design And Development Of A Process Control Temperature System For Eastern Oyster Crassostrea Virginica Research, Praveen Kolar Jan 2004

Design And Development Of A Process Control Temperature System For Eastern Oyster Crassostrea Virginica Research, Praveen Kolar

LSU Master's Theses

A process-control temperature system was designed and developed for facilitating somatic cell research on eastern oyster Crassostrea virginica. The system consisted of sixteen independent tanks capable of individual temperature regimes controlled by a central computer. Food grade 250-L tanks were used to hold 60 oysters per tank. Each tank was equipped with heating and cooling mechanisms. Immersion heaters were used for heating and a pump and a stainless steel heat exchangers immersed in chilled water (~ 7°C) were used for cooling. Type-T thermocouples along with a CIOEXP32 multiplexer board (Measurement Computing Inc.) were used to measure water temperatures. Control was …

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Design Of A Microfabricated Device For Ligase Detection Reaction (Ldr), Dwhyte Omar Barrett Jan 2004

Design Of A Microfabricated Device For Ligase Detection Reaction (Ldr), Dwhyte Omar Barrett

LSU Master's Theses

The Ligase Detection Reaction (LDR) is a mutation detection technique used to identify point mutations in deoxyribonucleic acid (DNA). Developed by Francis Barany and associates at Cornell University it is used to find specific low abundant point mutations that may lead to colorectal cancer in the early stages of disease development. The research objective was to design and manufacture a microscale Ligase Detection Reaction (LDR) device in polycarbonate. The LDR module will be incorporated with other microdevices such as: Continuous Flow Polymerase Chain Reaction (CFRCR) and Capillary Electrophoresis (CE) in modular lab-on-a-chip technology. In making the microdevice, the duration of …

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Metal-Doped Rare Earth Oxide Catalysts For Condensations To Ketones, Arvind Karkal Bhat Jan 2004

Metal-Doped Rare Earth Oxide Catalysts For Condensations To Ketones, Arvind Karkal Bhat

LSU Master's Theses

Metal-doped supported rare earth oxide catalysts were examined to determine their suitability for the decarboxylative condensation of two carboxylic acids to produce ketones. The catalysts were characterized based on chemisorption tests, coke analysis using thermo-gravimetric analysis and X-ray absorption spectroscopy. Effect of catalyst particle size on rate of reaction was studied for various supported cerium oxide catalysts. Catalysts were tested for activity, selectivity, and stability using isothermal fixed bed reactors. Optimal operating conditions for the production of diisopropyl ketone and methyl nonyl ketone were determined. It was found that supported cerium oxide catalysts effectively catalyzed the condensation of isobutyric acid …

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Towards Automation Of Forensic Facial Reconstruction, Hemant Narendra Khatod Jan 2004

Towards Automation Of Forensic Facial Reconstruction, Hemant Narendra Khatod

LSU Master's Theses

Forensic facial reconstruction is a blend of art and science thus computerizing the process leads to numerous solutions. However, complete automation remains a challenge. This research concentrates on automating the first phase of forensic facial reconstruction which is automatic landmark detection by model fitting and extraction of feature points. Detection of landmarks is a challenging task since the skull orientation in a 3D scanned data cloud is generally arbitrary and unknown. To address the issue, well defined skull and mandible models with known geometric structure, features and orientation are (1) aligned and (2) fit to the scanned data. After model …

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Bacterial Plume Dynamics In The Marshland Upwelling System Employed In The Near Freshwater Conditions, Benjamin Kojo Addo Jan 2004

Bacterial Plume Dynamics In The Marshland Upwelling System Employed In The Near Freshwater Conditions, Benjamin Kojo Addo

LSU Master's Theses

The marshland upwelling system (MUS) was installed in a floatation marsh along the banks of the Bayou Segnette Waterway, Louisiana. This site was characterized by native groundwater of low salinity regime. Previous studies focused on the removal of fecal pathogens from settled/raw and secondarily treated wastewater under high saline groundwater conditions. The objectives of this research were to: 1) quantify the impact of natural die-off on bacterial removal within the MUS, 2) determine bacterial retardation rates in laboratory-repacked sandy loam soil columns, and 3) evaluate the effectiveness of the MUS in removing fecal pathogens from settled, raw wastewater. Varying salinities …

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Evolution Of Base Substitution Gradients In Primate Mitochondrial Genomes, Sameer Raina Jan 2004

Evolution Of Base Substitution Gradients In Primate Mitochondrial Genomes, Sameer Raina

LSU Master's Theses

The availability of large amounts of genetic data from the mitochondrial DNA of species has created an unprecedented opportunity for the study of evolutionary processes. Being our closest relatives on the evolutionary tree the primates are a prime candidate for the study of evolutionary processes. The availability of large amounts of genetic data from the primates allows us to study and compare results from different phylogenetic reconstruction methods and to study and trace rudimentary evolutionary processes within the primate lineage. The evolutionary process studied here is the response of the nucleotide frequency ratios to single-strandedness of sites during mitochondrial DNA …

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Removal Of Toxic Organics In Wetlands: A Mechanistic Model, Luz Edith Florez Jan 2004

Removal Of Toxic Organics In Wetlands: A Mechanistic Model, Luz Edith Florez

LSU Master's Theses

The ability of removing toxic organic compounds in natural systems is important due to the capacity of these toxicants to increase risk of diseases when they are ingested by humans. This study developed a mechanistic model to estimate the removal efficiency of toxic organics in wetlands using the tanks-in-series model. Sensitivity analyses were performed for different values of the hydraulic loading rate and two kinds of wetlands: bottomland hardwood forest and freshwater marsh. It was observed the effect in the removal efficiency by the number of cell in series was principally perceived for values of N between 1 and 4; …

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Optimal Rate Of Freezing Biological Systems, Sreedhar Thirumala Jan 2004

Optimal Rate Of Freezing Biological Systems, Sreedhar Thirumala

LSU Master's Theses

This thesis addresses optimization techniques for cryopreservation of biological systems. A part of the thesis (Chapter 2) reports a simplified procedure to predict the optimal rate of freezing biological systems once the cell level parameters are known a priori. The key cell level parameters investigated were, reference permeability of the membrane to water (Lpg), apparent activation energy (ELp), inactive cell volume (Vb), diameter (D), and the ratio of the available surface area for water transport to the initial volume of intracellular water (SA/WV). The simplified procedure was developed by performing a thorough analysis of the water transport model over a …

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Joint Optimization Of Process Improvement Investments For Supplier-Buyer Cooperative Commerce, Erick Comeaux Jan 2004

Joint Optimization Of Process Improvement Investments For Supplier-Buyer Cooperative Commerce, Erick Comeaux

LSU Master's Theses

This research focuses on supporting the formation of strategic alliances through the concept of cooperative commerce, where suppliers and buyers work together to jointly optimize their businesses. The general goal of this research is to examine existing cooperative commerce models for obstacles that would hinder their successful implementation into modern industrial applications and to address those shortcomings. Total annual cost equations are formulated to capture the joint total relevant cost of cooperative commerce business relationships. These total joint relevant cost models will include terms that capture the ordering cost, holding cost, and cost of quality, as well as any applicable …

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Iddq Testing Of A Cmos First Order Sigma-Delta Modulator Of An 8-Bit Oversampling Adc, Anand K. Chamakura Jan 2004

Iddq Testing Of A Cmos First Order Sigma-Delta Modulator Of An 8-Bit Oversampling Adc, Anand K. Chamakura

LSU Master's Theses

This work presents IDDQ testing of a CMOS first order sigma-delta modulator of an 8-bit oversampling analog-to-digital converter using a built-in current sensor [BICS]. Gate-drain, source-drain, gate-source and gate-substrate bridging faults are injected using fault injection transistors. All the four faults cause varying fault currents and are successfully detected by the BICS at a good operation speed. The BICS have a negligible impact on the performance of the modulator and an external pin is provided to completely cut-off the BICS from the modulator. The modulator was designed and fabricated in 1.5 μm n-well CMOS process. The decimator was designed on …

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Modeling Of River Hydrodynamics And Active Cap Effectiveness In The Anacostia River, Keegan L. Roberts Jan 2004

Modeling Of River Hydrodynamics And Active Cap Effectiveness In The Anacostia River, Keegan L. Roberts

LSU Master's Theses

The Anacostia Active Capping Project (AACP) is a United States Environmental Protection Agency (EPA) funded initiative to develop and implement, on a field scale, active capping barrier technologies. Overseen by the Hazardous Substance Research Center, South and Southwest (HSRC), the AACP plans to demonstrate the ability of active capping barrier technologies to prevent the migration of contaminants from the sediment bed to the overlying water column of the Anacostia River. The demonstration project will involve the placement and monitoring of four individual types of capping materials (apatite, Aquablok, coke breeze, and sand) and the monitoring of one control (i.e. uncapped) …

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Design, Fabrication And Thermomechanical Testing Of A Vertical Bimorph Sensor In The Wafer Plane, Madhulika Sathe Jan 2004

Design, Fabrication And Thermomechanical Testing Of A Vertical Bimorph Sensor In The Wafer Plane, Madhulika Sathe

LSU Master's Theses

A bimetallic recurve device was designed, fabricated and tested as a temperature sensor. The device is to be used for sensing temperatures up to 300 C inside oil wells for downhole condition monitoring. Continuous downhole measurements at high temperatures and pressures are required to monitor conditions downhole instruments are exposed to during use. Currently mercury thermometers and resistive temperature detectors (RTD) are used for downhole temperature measurements. Microsensors have potential application downhole, due to their small size and inherent robustness. The principle of a bimetallic beam was used to measure temperature. A bimetallic beam deflects with changes in temperature due …

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Study Of Characteristics Of Plasma Nitriding And Oxidation Of Superalloy In738lc, Mary Shanti Pampana Jan 2004

Study Of Characteristics Of Plasma Nitriding And Oxidation Of Superalloy In738lc, Mary Shanti Pampana

LSU Master's Theses

IN738LC is a nickel base superalloy, widely used in various applications in turbine engines at high temperatures. Its oxidation and nitriding characteristics were focused in this study. Oxidation kinetics of IN738LC in dry air was studied at selected temperatures, specially chosen depending on the chemical dynamics of the alloy at such high temperatures during annealing. Isothermal oxidation in dry air was carried out at 1000°C, 1090°C, 1140°C and 1190°C. XRD results indicated an interesting onset of preferred orientation in the ã’ depleted layer in all the samples. The XPS and XRD analyses revealed the main oxide phases present in the …

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Effects Of Automobile Seating Posture On Trunk Muscle Activity, Milton Maada-Gormoh Saidu Jan 2004

Effects Of Automobile Seating Posture On Trunk Muscle Activity, Milton Maada-Gormoh Saidu

LSU Master's Theses

Reports for adult population indicate that almost 80% of the adult population has reported some form of lower back aches. Each year American workers suffer more than 300,000 lost-time injuries involving musculoskeletal disorders of the back, with the costs that run into billions of dollars. Sedentary tasks are known to be major contributing factors of back pain. Prior studies have indicated that the myoelectric activity of the lumbar region decreases when the back rest inclination of a seat increased. An increase in seat pan inclination so that it increases pressure on the leg muscles is also a cause for back …

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Evaluation Of The Human Impact Of Password Authentication Practices On Information Security, Deborah Sater Carstens, Pamela R. Mccauley-Bell, Linda C. Malone, Ronald F. Demara Jan 2004

Evaluation Of The Human Impact Of Password Authentication Practices On Information Security, Deborah Sater Carstens, Pamela R. Mccauley-Bell, Linda C. Malone, Ronald F. Demara

Aeronautics Faculty Publications

The research objective was to develop a model for evaluating the human impact that password authentication issues are having on the security of information systems. Through distributing a survey and conducting an experiment, researchers created a model for predicting the vulnerability that a particular set of conditions will have on the likelihood of error in an information system. The survey consisted of over 250 respondents. The experiment consisted of 30 subjects and the analysis utilized a χ2 goodness of fit test. The findings indicate that human error associated with password authentication can be significantly reduced through the use of passwords …

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Tractor Test 1837c: New Holland Boomer 4055, Nebraska Tractor Test Lab Jan 2004

Tractor Test 1837c: New Holland Boomer 4055, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

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The Investigation Of A Wireless Medical Homecare Data Logger, Aisling Cronin Jan 2004

The Investigation Of A Wireless Medical Homecare Data Logger, Aisling Cronin

Masters

Modern, portable self-measurement devices such as hand-held glucometers and ECG instruments can provide feedback in electronic form to patients. However the information is mostly transmitted by proprietary cable and there is no agreed format for migrating this data to information systems in clinics where it can be used by clinicians. The result is a muddle of transport mechanisms and software. There is a clear need for a simple, open and agreed means of data communication to help patients to manage their condition and to support clinicians who engage in home telemonitoring. To allow patients freedom to move, the first stage …

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