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Articles 2521 - 2550 of 2820

Full-Text Articles in Engineering

An In-Situ Capping Design For The Remediation Of Petroleum Contaminated Sediments, Melanie Krystle Harris Jan 2005

An In-Situ Capping Design For The Remediation Of Petroleum Contaminated Sediments, Melanie Krystle Harris

LSU Master's Theses

Historical disposal practices used by oil companies have caused the accumulation of contaminated sediments in their nearby lakes and ponds. These companies are now faced with the challenge of remediating the bodies of water that contain these contaminated sediments. The contaminants that remain in the sediment continue to pose a threat to human health and the environment. For example, high concentrations of polycyclic aromatic hydrocarbons (PAHs), which are still present in the bottom sediments can have toxic effects on aquatic life. One form of remediation for this problem is In-Situ Capping (ISC), which is defined as a method whereby material …


Modeling And Experimentation Of Drying Of Adipose Derived Adult Stem Cells, Surbhi Mittal Jan 2005

Modeling And Experimentation Of Drying Of Adipose Derived Adult Stem Cells, Surbhi Mittal

LSU Master's Theses

Development of protocols for storing desiccated cells at ambient temperatures offers tremendous economic and practical advantages over traditional storage procedures such as cryopreservation and freeze-drying. An integrated frame work of experimentation and modeling is adopted in the present work to develop procedures for storage of adult stem cells at ambient temperature. As a first step, we have measured the post-rehydration membrane integrity of two passages, Passage-0 (P0) and Passage-1 (P1), of human adipose-derived stem cells (hASCs). hASCs were dried using a convective stage at three different drying rates (slow, moderate and rapid) in D-PBS with trehalose (50 mM) and glycerol …


Development Of An Alternative Approach To Estimate Vehicle Miles Traveled Using A Classification Procedure, Srividya Vadlamani Jan 2005

Development Of An Alternative Approach To Estimate Vehicle Miles Traveled Using A Classification Procedure, Srividya Vadlamani

LSU Master's Theses

In this study a Classification and Regression Tree (CART) classification system method was developed as an alternative to the HPMS conventional method of VMT estimation. Louisiana Highway Performance Monitoring System (HPMS) data from Federal Highway Administration (FHWA) and Louisiana highway network data from Louisiana Department of Transportation (LADOTD) were used to carry out the analysis. The CART classification was derived based on link attributes that effectively distinguished the homogeneous traffic volume sections. VMT estimation on individual links as well for the different systems was calculated using the CART classification system and the values were assigned on each link. The default …


Simulations And Experimental Analysis Of High-Aspect-Ratio Diffusive Micro-Mixers, Amit Maha Jan 2005

Simulations And Experimental Analysis Of High-Aspect-Ratio Diffusive Micro-Mixers, Amit Maha

LSU Master's Theses

Passive (diffusional) mixing has been used in designing high-aspect-ratio micro-mixers for the purpose of performing the Liagase Detection Reaction (LDR). A simple model was used to design such mixers optimized for pressure drop or time required to deliver a prescribed volume of mixture. The types of mixers considered are simple, cheap, and durable and can perform over a broad range of volumetric flow rates at reasonably modest pressure drops. The fluids typically have a very low diffusion coefficient of=1.2x10^10m^2/s, and thus diffusional mixing can only be effective in high-aspect-ratio micro-channels. A realizable aspect ratio of 6 has been considered initially …


Modeling The Hydrologic And Particulate Loadings From Paved Urban Surfaces, Chad Michael Cristina Jan 2004

Modeling The Hydrologic And Particulate Loadings From Paved Urban Surfaces, Chad Michael Cristina

LSU Doctoral Dissertations

This dissertation details the results of recent investigations concerning non-colloidal particulate matter found in urban rainfall-runoff and urban snowmelt. Three forms of the power law model (PLM) were used to model particle number density. It was found that significant model error could be introduced into PLMs when the median diameter particle was used to estimate the number of particles per interval, but the SSE of continuous PLMs could be significantly reduced through the use of correction factors when the sieve interval was large (P<0.05). Additionally, a multiple PLM analysis may be more appropriate than a single PLM analysis when changes in particle population occur within a single gradation. PLMs were also used to model the relationship between cumulative granulometric mass and cumulative particulate-bound metal mass. The use of such calibrated PLMs provided considerable cost reduction when compared to conventional direct measurements of particulate-bound metal mass. A first flush analysis indicated that only events with average volumetric flow rates approaching 1 L/min/m of drainage width exhibit a rapid depletion of particulate matter consistent with the concentration-based definition of the first flush. An analysis of particle separation mechanisms indicated that 90% of these particles, by mass, could be removed from the discharge with detention times of 30 min and 120 min for snowmelt and rainfall-runoff, respectively, in a typical roadside drainage system. It was also found that the kinematic wave model could accurately model significant aspects of rainfall-runoff events in traffic-impacted watersheds provided that abstractions were incorporated into the modeling process. For this watershed the source of abstraction was attributable to vehicular traffic. For high-intensity events with more than 10 vehicles per runoff volume (VPV) the runoff coefficient varied between 0.6 and 0.9 while for low-intensity events with fewer than 10 VPV the coefficient ranged between 0.2 and 0.4.


Processing, Microstructure And Mechanical Behavior Of Nanocomposite Multilayers, Zuqiang Qi Jan 2004

Processing, Microstructure And Mechanical Behavior Of Nanocomposite Multilayers, Zuqiang Qi

LSU Doctoral Dissertations

Nanoscale multilayer coatings have high potential for numerous engineering applications because they can exhibit enhanced properties due to nanoscale effects and combine different properties from individual components. At present, scale effects on the mechanical behavior of multilayers are not well understood. Three multilayer nanocomposite systems, namely Al/Al2O3, Ti/TiN, and Cr/a-C, have been synthesized by using a dual-gun e-beam physical vapor deposition, to investigate the effect of layer thickness, the nature of components and their microstructures on the mechanical behavior. The deposited Al and Ti nanolayers were found to have polycrystalline fcc and hcp structure, respectively, the Cr and TiN layers …


Turbine Blade Tip Cooling And Heat Transfer, Hasan Nasir Jan 2004

Turbine Blade Tip Cooling And Heat Transfer, Hasan Nasir

LSU Doctoral Dissertations

Turbine blade tip leakage flow from blade pressure side to suction side over the tip surface increases the thermal loading to the blade tip, leading to a high local temperature and thus, is considered one of the primary sources of blade failure. Leakage flow can be reduced by using a recessed or squealer tip blade or by cooling the blade tip to incorporate film cooling. The performance of different recessed tip geometries were investigated and compared with plane tip performance. A transient liquid crystal technique was employed to measure detailed heat transfer coefficient distributions. Coolant injection from holes located on …


Multifunctional Nanocomposite Co-Containing Diamondlike Carbon Thin Films, Fengli Wang Jan 2004

Multifunctional Nanocomposite Co-Containing Diamondlike Carbon Thin Films, Fengli Wang

LSU Doctoral Dissertations

Metal-containing, hydrogenated carbon films (Me-a-C:H) is a special class of nanocomposite films of particular interest since they can be multifunctional through the synergistic interaction of their individual components. Thus, nanocomposite thin films possess high potential in a wide field of engineering applications, especially in small scale devices. A series of multifunctional nanocomposite Co-a-C:H thin films have been synthesized by a hybrid chemical vapor deposition (CVD) and physical vapor deposition (PVD) process to uncover the relationship between synthesis, microstructure and properties. The effects of deposition parameters on the microstructural evolution and properties have been systematically studied. The results showed that the …


Replication Of Metal-Based High-Aspect Microscale Structures By High Temperature Micromolding, Dongmei Cao Jan 2004

Replication Of Metal-Based High-Aspect Microscale Structures By High Temperature Micromolding, Dongmei Cao

LSU Doctoral Dissertations

In microsystem technology a large range of materials will be available only after the necessary microfabrication technologies have been developed or adapted. More than a decade ago, the existing microfabrication technologies were restricted to structuring and shaping techniques producing three-dimensional microstructures out of silicon, mostly unfilled plastics or a few pure metals or binary alloys. However, the choice of materials for microcomponents is determined by the function and conditions of use of microsystems. Some microdevices can only work well when made of specific metal components. To meet this need, several microfabrication techniques have been developed, such as second electroforming of …


Small And Large Strain Monitoring Of Unsaturated Soil Behavior By Means Of Multiaxial Testing And Shear Wave Propagation, Oscar F. Porras Ortiz Jan 2004

Small And Large Strain Monitoring Of Unsaturated Soil Behavior By Means Of Multiaxial Testing And Shear Wave Propagation, Oscar F. Porras Ortiz

LSU Doctoral Dissertations

The deformation and strength behavior of dry and saturated soils is controlled by the effective stresses as defined by Terzaghi. However, Terzaghi’s definition of the effective stresses fails for unsaturated soils, as capillarity force influence is also important. The effects of capillarity forces in soil are evaluated by the concept of matrix suction. Several techniques are used to evaluate soil suction however their applications involve difficult calibrations and tedious methodology. Furthermore, suction is a microscopic property and it is influenced by interparticle soil attraction, which can change by sampling disturbance. This research program evaluates the effect of suction on stiffness …


Stabilization Of Flue Gas Desulfurization Sludge For Application In Marine Environments, Tej Kour Jan 2004

Stabilization Of Flue Gas Desulfurization Sludge For Application In Marine Environments, Tej Kour

LSU Master's Theses

Flue Gas Desulfurization sludge (FGD, CaSO4·2H2O, CaSO3·1/2H2O) is a waste by-product produced when sorbent slurry is passed through wet scrubbers. FGD contains higher concentrations of Ca, S, Si, Fe, Al and Br making it of great environmental concern. Presently only 16% of 24 million metric tons (MT) of FGD sludge produced is being recycled; the rest is disposed in landfills. This research was focused towards stabilizing FGD sludge with Portland Type II cement and Class C fly ash to produce lightweight fill material to be used in the construction of coastal devices. The specific objectives included the development of a …


Evaluation Of New Methods For Processing Drilling Data To Determine The Cause Of Changes In Bit Performance, Jaime Solano Jan 2004

Evaluation Of New Methods For Processing Drilling Data To Determine The Cause Of Changes In Bit Performance, Jaime Solano

LSU Master's Theses

Drilling operations represent the major cost in finding and developing new petroleum reserves. Poor drilling performance when drilling deep shale and strong rocks, as evidenced by slow rate of penetration (ROP), has a significant detrimental impact on drilling costs. Also, it has been concluded that bit balling is the main cause of low ROP when drilling deep, clay-rich shale with water-based mud. In addition, it is estimated that a potential saving in drilling cost of hundreds of millions of dollars a year can be obtained if bit balling is mitigated and ROP is improved. Several methods have been developed in …


Development Of A Methodology To Delineate Hurricane Evacuation Zones, Nandagopal Meduri Jan 2004

Development Of A Methodology To Delineate Hurricane Evacuation Zones, Nandagopal Meduri

LSU Master's Theses

The main focus of this study is to exhibit a simple and easily implemented process to identify hurricane evacuation zones. The proposed study presents a new methodology to delineate hurricane evacuation zones. The new methodology helps in easier identification of zones, thereby making the task of evacuation officials easier. Hurricane evacuation zones were identified based on the elevation of the points comprising the study area. An area layer was created based on the storm surge models run, and were overlaid with zip code boundary layer and land use data available. Elevation point file data was superimposed on the study area …


Kinetic Analysis Of Kluyveromyces Marxianus Yeast Strain, Erika Guimaraes Madeira Reeves Jan 2004

Kinetic Analysis Of Kluyveromyces Marxianus Yeast Strain, Erika Guimaraes Madeira Reeves

LSU Master's Theses

This research investigated the growth kinetic parameters (Ks and µmax) of the Kluyveromyces marxianus yeast strain for a batch process under aerobic and anaerobic conditions at 45oC using the Two-Liter Bioflo® 2000 Fermentors and the Orbital Shaker Bed with 250mL flasks (New Brunswick Scientific). This yeast strain was grown in twelve different glucose media concentrations (Anderson et al. 1986), ranging from 200 mg/L to 80,000 mg/L. Several analytical techniques were used, such as COD measurement to determine soluble and total substrate concentrations, TSS and OD measurements to determine biomass formation, HPLC measurements to determine carbohydrate concentrations, and GC measurements to …


An Evaluation Of Multiple Branch Predictor And Trace Cache Advanced Fetch Unit Designs For Dynamically Scheduled Superscalar Processors, Slade S. Maurer Jan 2004

An Evaluation Of Multiple Branch Predictor And Trace Cache Advanced Fetch Unit Designs For Dynamically Scheduled Superscalar Processors, Slade S. Maurer

LSU Master's Theses

Semiconductor feature size continues to decrease permitting superscalar microprocessors to continue to increase the number of functional units available for execution. As the instruction issue width increases beyond the five instruction average basic block size of integer programs, more than one basic block must be issued per cycle to continue to increase instructions per cycle (IPC) performance. Researchers have created methods of fetching instructions beyond the first taken branch to overcome the bottleneck created by the limitations of conventional single branch predictors. We compare the performance of the multiple branch prediction (MBP) and trace cache (TC) fetch unit optimization methods. …


Optimal Test Case Selection For Multi-Component Software System, Praveen Babu Kysetti Jan 2004

Optimal Test Case Selection For Multi-Component Software System, Praveen Babu Kysetti

LSU Master's Theses

The omnipresence of software has forced upon the industry to produce efficient software in a short time. These requirements can be met by code reusability and software testing. Code reusability is achieved by developing software as components/modules rather than a single block. Software coding teams are becoming large to satiate the need of massive requirements. Large teams could work easily if software is developed in a modular fashion. It would be pointless to have software that would crash often. Testing makes the software more reliable. Modularity and reliability is the need of the day. Testing is usually carried out using …


Development Of A Neural Network Approach For The Assessment Of The Performance Of Traffic Sign Retroreflectivity, Nagajyothi Swargam Jan 2004

Development Of A Neural Network Approach For The Assessment Of The Performance Of Traffic Sign Retroreflectivity, Nagajyothi Swargam

LSU Master's Theses

The goal of the research was to develop a new predictive tool for assessing the performance of traffic sign retroreflectivity and to compare the developed tool with the existing linear regression models. Retroreflectivity decreases as sign sheeting ages. Currently Louisiana Department of Transportation and Development (LADOTD) replace signs with low reflectivity based on driver complaints. This practice might have resulted in premature sign replacement (removal of signs with several years of in-service life still remaining) or in non-replacement of signs that are not in compliance with LADOTD minimum reflectivity standards. In this study, both neural network models and regression models …


Zooplankton Visualization System: Design And Real-Time Lossless Image Compression, Dattatreya Reddy Tetala Satya Surya Jan 2004

Zooplankton Visualization System: Design And Real-Time Lossless Image Compression, Dattatreya Reddy Tetala Satya Surya

LSU Master's Theses

In this thesis, I present a design of a small, self-contained, underwater plankton imaging system. I base the imaging system’s design on an embedded PC architecture based on PC/104-Plus standards to meet the compact size and low power requirements. I developed a simple graphical user interface to run on a real-time operating system to control the imaging system. I also address how a real-time image compression scheme implemented on an FPGA chip speeds up image transfer speeds of the imaging system. Since lossless compression of the image is required in order to retain all image details, I began with an …


Effects Of Corrosion Prevention Compounds And Overload Induced Residual Stress Field On Fatigue Life In Aluminum Alloy, Jin Hee Park Jan 2004

Effects Of Corrosion Prevention Compounds And Overload Induced Residual Stress Field On Fatigue Life In Aluminum Alloy, Jin Hee Park

LSU Master's Theses

Corrosion-Prevention Compounds (CPC) are commonly used to prevent corrosion in the aircraft industry. The presence of corrosive environment (salt-fog, water-fog, even dry air) on aircraft structures has detrimental effects on the integrity of aircraft components which reduces the fatigue life and may accelerate the crack growth rate in the structures. This thesis work is aimed at identifying the effect of CPC and corrosion fatigue on the fatigue life of test specimen. This study describes the results of an experimental study on aluminum alloy 2024-T3 with center-crack specimen to investigate the effect of CPC on fatigue life. Generally, these compounds contain …


Application Of Stochastic Downscaling Techniques To Global Climate Model Data For Regional Climate Prediction, Suchita Potta Jan 2004

Application Of Stochastic Downscaling Techniques To Global Climate Model Data For Regional Climate Prediction, Suchita Potta

LSU Master's Theses

Global warming is the most important issue of the present day that affects the climate drastically. This research was carried out to find out the effects of Global warming on Louisiana in future on a very finer spatial and temporal scale. For this purpose spatial downscaling technique is used, where finer resolution climate information is derived from a coarser resolution Global Climate Model (GCM) output. Empirical/statistical downscaling method is used in which sub grid scale changes are calculated as a function of large scale climate. For this purpose a stochastic weather generator and two Global models are considered. The two …


Experimental Validation Of A Smart-Bias Active Magnetic Bearing Controller, Shailesh Pradhananga Jan 2004

Experimental Validation Of A Smart-Bias Active Magnetic Bearing Controller, Shailesh Pradhananga

LSU Master's Theses

Active magnetic bearings (AMBs) are being increasingly employed in the aerospace industry in a variety of devices including compressors, turbines, pumps, and flywheels. One application of great interest to future space missions is the Integrated Power and Attitude Control System (IPACS). The IPACS consists of an arrangement of flywheels that integrates the energy storage and attitude control functions into a single system; thereby, reducing the spacecraft mass, volume, launching cost, and maintenance. Like any energy storage system, flywheels need to be operated with low power losses. AMBs are ideally suited for flywheels because they eliminate mechanical losses (friction). Nevertheless, AMBs …


Effects Of Pressure Suit And Race On Functional Reach, Static And Dynamic Strength, Nageswara Rao Uppu Jan 2004

Effects Of Pressure Suit And Race On Functional Reach, Static And Dynamic Strength, Nageswara Rao Uppu

LSU Master's Theses

In the design of any manual workspace, it is important for the designers to have access to data that can illustrate reach capabilities under real-time work situation. Wearing bulky clothing (pressure suit) and protective restraints (seat or shoulder harness belts) is often mandatory in high acceleration work environments. Clothing and personal equipment worn can influence the functional reach and strength values since they add to the body size. The present study was conducted to investigate the effect of wearing a VKK-6M pressure suit on functional reach limitations and strength values. The technology of incorporating body dimensions into cockpit design primarily …


Bezier Curves For Metamodeling Of Simulation Output, Harish J. Kingre Jan 2004

Bezier Curves For Metamodeling Of Simulation Output, Harish J. Kingre

LSU Master's Theses

Many design optimization problems rely on simulation models to obtain feasible solutions. Even with substantial improvement in the computational capability of computers, the enormous cost of computation needed for simulation makes it impractical to rely on simulation models. The use of metamodels or surrogate approximations in place of actual simulation models makes analysis realistic by reducing computational burden. There are many popular metamodeling techniques such as Polynomial Regression, Multivariate Adaptive Regression Splines, Radial Basis Functions, Kriging and Artificial Neural Networks. This research proposes a new metamodeling technique that uses Bezier curves and patches. The Bezier curve method is based on …


Survivable Multicasting In Wdm Optical Networks, Sateesh Chandra Shekhar Jan 2004

Survivable Multicasting In Wdm Optical Networks, Sateesh Chandra Shekhar

LSU Master's Theses

Opportunities abound in the global content delivery service market and it is here that multicasting is proving to be a powerful feature. In WDM networks, optical splitting is widely used to achieve multicasting. It removes the complications of optical-electronic-optical conversions [1]. Several multicasting algorithms have been proposed in the literature for building light trees. As the amount of fiber deployment increases in networks, the risk of losing large volumes of data traffic due to a fiber span cut or due to node failure also increases. In this thesis we propose heuristic schemes to make the primary multicast trees resilient to …


Testing A Cmos Operational Amplifier Circuit Using A Combination Of Oscillation And Iddq Test Methods, Pavan K. Alli Jan 2004

Testing A Cmos Operational Amplifier Circuit Using A Combination Of Oscillation And Iddq Test Methods, Pavan K. Alli

LSU Master's Theses

This work presents a case study, which attempts to improve the fault diagnosis and testability of the oscillation testing methodology applied to a typical two-stage CMOS operational amplifier. The proposed test method takes the advantage of good fault coverage through the use of a simple oscillation based test technique, which needs no test signal generation and combines it with quiescent supply current (IDDQ) testing to provide a fault confirmation. A built in current sensor (BICS), which introduces insignificant performance degradation of the circuit-under-test (CUT), has been utilized to monitor the power supply quiescent current changes in the CUT. The testability …


Trajectory And Window Width Predictions For A Cased Hole Sidetrack Using A Whipstock, Harshad Prakash Patil Jan 2004

Trajectory And Window Width Predictions For A Cased Hole Sidetrack Using A Whipstock, Harshad Prakash Patil

LSU Master's Theses

The Trackmaster system manufactured by Smith Services consists of a multi-ramped whipstock and a trimill assembly used to perform a sidetrack from a cased well. Smith Services has observed evidence that the trimill assembly may prematurely leave the face of the whipstock and build excess inclination and dogleg severity or may fall into the original well immediately after leaving the end of the whipstock ramp thus creating a need to predict the borehole trajectory for sidetracking operations. The goal of this project was to predict the borehole trajectory and the window profile cut in the casing by the sidetracking equipment …


Development Of A True Triaxial Apparatus For Soil Testing, Heath Stuart Williams Jan 2004

Development Of A True Triaxial Apparatus For Soil Testing, Heath Stuart Williams

LSU Master's Theses

This thesis presents the development of a True Triaxial Testing TTT Apparatus. The TTT apparatus developed has the capabilities of applying the three principal stresses to a rectangular prismoidal specimen independently. The minor principal stress is provided by the cell pressure. The major principal stress is provided by a load actuator traveling at a constant velocity. A LabView software program instantaneously reads instrumentation, makes calculations, and commands a second load actuator to induce an intermediate principal stress that maintains a constant b-value; where b-value is equal to the intermediate principal stress minus the minor principal stress divided by the major …


Modeling Of Cane Sugar Colorant Removal In Packed-Bed Ion Exchange Columns And An Investigation Into Pretreatment Methods, Bruce Malcolm Ellis Jan 2004

Modeling Of Cane Sugar Colorant Removal In Packed-Bed Ion Exchange Columns And An Investigation Into Pretreatment Methods, Bruce Malcolm Ellis

LSU Master's Theses

Cane sugar colorants have been extensively researched but still little is known about their exact compositions. Rather than distinct compounds, they are a mixture of many compounds. Some it is assumed can be classified into the pseudo components that have been defined using gel permeation chromatography, based on molecular weight. The defining of these components has allowed the colorants to be modeled independently, instead of as one lumped color parameter. The measured colored components were modeled using a linear driving force adsorption model, which could be applied in the design process for optimizing the decolorizing capacity of the resins. The …


Assessment Of Shearing Phenomenon And Porosity Of Porous Media Using Microfocus Computed Tomography, Bashar Adeeb Alramahi Jan 2004

Assessment Of Shearing Phenomenon And Porosity Of Porous Media Using Microfocus Computed Tomography, Bashar Adeeb Alramahi

LSU Master's Theses

Microfocus x-ray computed tomography (μCT) is a powerful non-destructive scanning technique to study the internal fabric of granular materials. In this thesis, μCT was applied to two cases. The first case involves studying the behavior of particles in a triaxial specimen during shearing. Three-dimensional translation and rotation of the particles were tracked throughout the shearing process, and they were used to calculate the local strain distributions. Moreover, the local dilatancy angle distribution was calculated throughout experiment. These distributions were compared to study the changes in the behavior of the particles at different stages of the test. It was noticed that …


A Bio-Mems Device For Separation Of Breast Cancer Cells From Peripheral Whole Blood, Juan Feng Jan 2004

A Bio-Mems Device For Separation Of Breast Cancer Cells From Peripheral Whole Blood, Juan Feng

LSU Master's Theses

This work demonstrates the application of Bio-Micro Electro Mechanical System (Bio-MEMS) technology for early breast cancer detection and diagnosis. Early breast cancer detection and diagnosis typically uses conventional mammogram screening followed by biopsy, which can be problematic since mammography can only detect highly calcified tumors greater than 1 cm in size. A micro-device was developed to identify and specifically collect tumor cells of low abundance (1 tumor cell among 107 normal blood cells) from circulating whole blood. By immobilizing anti-EpCAM (Epithelial Cell Adhesion Molecule) antibodies on polymer micro-channel walls by the chemical surface modification of PMMA, breast cancer cells …