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Articles 1951 - 1980 of 2820

Full-Text Articles in Engineering

Computational Examination Of Compaction Wave-Boundary Interaction In Granular Explosive, Anirban Mandal Jan 2010

Computational Examination Of Compaction Wave-Boundary Interaction In Granular Explosive, Anirban Mandal

LSU Master's Theses

Interactions between initially planar, piston supported compaction waves in heterogeneous energetic solids and macro-scale rigid boundaries were computationally examined for a wide range of piston impact speeds (20 ≤ Up ≤ 500 m/s) and initial solid volume fractions of the material (0.73 ≤ ϕ0 ≤ 0.90). The response of the material was described by a continuum theory that accounts for both elastic and inelastic compaction in a thermodynamically consistent manner. Initial conditions were imposed by interpolating the spatial structure of one-dimensional steady compaction waves onto two-dimensional domains considered in this study. For a planar wedge boundary, the peak …


Surfactant-Induced Flow Behavior Effects In Gas Condensate Reservoirs, Bikash Deep. Saikia Jan 2010

Surfactant-Induced Flow Behavior Effects In Gas Condensate Reservoirs, Bikash Deep. Saikia

LSU Master's Theses

Natural gas, which accounts for a quarter of world’s energy, has been a major energy source because of its abundance and less impact on environment. With explorations at higher depth, pressure and temperature, the share of gas condensate reservoirs to global gas production is increasing. A unique production challenge associated with these reservoirs is the condensate blockage problem, which is the buildup of condensate liquid saturation around wellbore as a result of drawdown below dew point pressure. Mitigation of this problem requires in depth understanding of the multiphase flow of liquid and gas. Surfactants are well known in the literature …


Development Of A Compact Optical System For A Forward-Looking Endoscope, Anandi Kalyan Dutta Jan 2010

Development Of A Compact Optical System For A Forward-Looking Endoscope, Anandi Kalyan Dutta

LSU Master's Theses

ABSTRACT Optical Coherence Tomography has been effectively used for endoscopy in many previous studies. In this work, a 2 mm diameter forward-looking endoscope is developed with the help of MEMS technology and Optical Coherence Technology (OCT) to obtain in-vivo cross-sectional images of tissues or body cavities. The design consists of a GRIN lens, optical fiber and MEMS chip that are placed in line to fulfill the aim of achieving a 2 mm diameter probe. A standard assembly process has been established for the probe. An anisotropic etching was performed on the sample chip to create the V-groove for carrying the …


Assessing The Suitability Of Coagulation Pretreatment On Poultry Processing Wastewater For Optimized Dissolved Air Flotation, Adam James Dassey Jan 2010

Assessing The Suitability Of Coagulation Pretreatment On Poultry Processing Wastewater For Optimized Dissolved Air Flotation, Adam James Dassey

LSU Master's Theses

Eleven metal coagulants and one polyelectrolyte were assessed on their suitability for assisting a dissolved air flotation (DAF) system in treating poultry processing wastewater. The DAF unit was designed to maximize the microbubble production by varying the pressure, temperature, hydraulic retention time, and air flow parameters. The maximum microbubble flow from the designed system produced 30 mL of air per L of water. This value was considered low compared to other systems, but attempts to increase the microbubble volume in the current system beyond this value resulted in the coalescing of microbubbles due to turbulent conditions. Jar tests were used …


Modeling Pm Rotary-Linear Motors With Twin-Stator Using 3d Femm, Oleksandr Dobzhanskyi Jan 2010

Modeling Pm Rotary-Linear Motors With Twin-Stator Using 3d Femm, Oleksandr Dobzhanskyi

LSU Master's Theses

A rapid growth of automatization nowadays requires electric machines to be adjusted to any technological process. Therefore, a need in machines with two degrees of mechanical freedom (TDMF), which can operate rotationally and linearly, is relatively large. This thesis is directed on the design and study of performance of PM (permanent magnet) rotary-linear synchronous motors with twin-armature as a new type of electric machines which can perform linear, rotational and helical movements. Three stator versions are considered, namely: stator with rotary and linear armatures, two rotary armatures, and two linear armatures. The rotors have PMs skewed with respect to the …


Biomechanical Evaluation Of Modified Track Shoes, Marlon Alberetos Greensword Jan 2010

Biomechanical Evaluation Of Modified Track Shoes, Marlon Alberetos Greensword

LSU Master's Theses

Track and field runners, especially sprinters and mid-distance runners, face many problems due to walking in spike shoes. Due to the fact that track and field spike shoes are designed specifically for running, the runner’s feet remain in an uncomfortable, flexed position when walking between workouts and races. Problems caused by the dangerous foot-positioning include, but are not limited to, the following: back pain, shin splints, bone spurs, blisters, and overall decreased level of running performance. Over time, runners wearing improper footwear for walking may face chronic injuries such as plantar fasciitis, shin splints, Achilles tendinitis, chondromalacia, and iliotibial band …


Adaptive Quantization In Wireless Sensor Networks With Encryption, Niharika Konakalla Jan 2010

Adaptive Quantization In Wireless Sensor Networks With Encryption, Niharika Konakalla

LSU Master's Theses

We consider the estimation of a deterministic unknown parameter in an encrypted wireless sensor networks. Adaptive quantization is used on the sensor's observation and the outputs of the sensors are then encrypted using a probabilistic cipher. In a conventional fixed quantization scheme, estimation error grows exponentially with the difference between the threshold and the unknown parameter to be estimated. Hence, to avoid this, we used and adaptive quantization scheme where each sensor adaptively adjusts its quantization threshold. We find the Cramer-Rao Lower Bound for the Ally Fusion Center (AFC) and then find the optimal estimate of the unknown parameter for …


Integrating Lattice Space-Time Codes Of Highest Rank And Multiplexing Over Rayleigh Fading Channels, Vamshi Krishna Samudrala Jan 2010

Integrating Lattice Space-Time Codes Of Highest Rank And Multiplexing Over Rayleigh Fading Channels, Vamshi Krishna Samudrala

LSU Master's Theses

In this thesis, we consider the problem of finding an optimal combination of multiplexing and space-time coding over a MIMO array when a transmitter has a prior knowledge about correlation. Some existing work in this area used multiplexing and space-time coding methods as a technique to achieve capacity over a MIMO wireless channel. In this work, we consider a 2x2 lattice space-time code of highest rank and multiplex it over a MIMO system to improve the bit error rate performance. The main focus of this thesis is to address the problem of switching between spatial multiplexing and space-time coding to …


Enhancement Of Single-Lap Joint Strength Under Tension Using Piezoelectric Actuation, Ryan Michael Meyer Jan 2010

Enhancement Of Single-Lap Joint Strength Under Tension Using Piezoelectric Actuation, Ryan Michael Meyer

LSU Master's Theses

Composite adhesively bonded joint structures have seen increased use over conventional riveted due to their ease of manufacturing and quality strength-to-weight ratios. However, adhesively bonded joints lack the rigidity and failure strength of riveted assemblies, due to high stress concentrations which develop in the adhesive layer, which makes them prone to undesirable deformation and failure. Piezoelectric materials feature the ability to produce mechanical strain when subjected to an applied voltage and vice-versa. Therefore, it is proposed to use piezoelectric actuators to transmit counterbalancing forces to increase the rigidity and strength of composite joints. Existing studies have been limited in that …


An Operational Policy For A Single Vendor Multi Buyer Integrated Inventory Supply Chain System Considering Shipping Time, Chiranjit Saha Jan 2010

An Operational Policy For A Single Vendor Multi Buyer Integrated Inventory Supply Chain System Considering Shipping Time, Chiranjit Saha

LSU Master's Theses

Since its introduction, the concept of integrated inventory supply chain has received a considerable amount of attention. The majority of studies in the last three decades revealed an increase in holding cost as product moves further down the chain or up the chain. A recent study Hoque (2008) considered vendor’s setup cost and inventory holding cost. Some research also considered fixed transportation cost, which is unrealistic. This study focuses on a single-vendor, multi-buyer scenario and presents three models. First, two models illustrate the transferring of equally-sized batches. Then, a third model considers the transferring of unequally-sized batches in a lot. …


Factors Affecting The Interface Shear Strength Of Pavement Layers, Nachiketa Bharat Patel Jan 2010

Factors Affecting The Interface Shear Strength Of Pavement Layers, Nachiketa Bharat Patel

LSU Master's Theses

Flexible pavement structures are built in layers with a certain degree of bonding at the interface, which is affected by several factors which could be either material related, or construction related. The tack coat material type, residual application rate, tack coat coverage, and pavement surface type are attributed as material related factors. On the other hand, cleanliness, moisture, and vertical confinement pressure could be classified as construction related factors. The objective of this study was to quantify the effects of these factors on the pavement interface bonding in terms of interface shear strength. Five types of tack coats, four of …


An Experimental Study Of Surfactant Enhanced Waterflooding, Paulina Metili Mwangi Jan 2010

An Experimental Study Of Surfactant Enhanced Waterflooding, Paulina Metili Mwangi

LSU Master's Theses

Surfactants have a variety of applications in the petroleum industry due to their remarkable ability to lower the oil-water interfacial tension and alter wettability. However, surfactant adsorption on rock surfaces has severely crippled this means of improving oil recovery due to the high cost associated with the large quantities of surfactant needed. A previous experimental study by Ayirala (2002) reported the development of mixed wettability using a nonionic surfactant. At this mixed-wet state he was able to recover about 94% of the original oil in place. The underlying motivation of this study was to achieve such high recoveries without using …


Dynamic Model Of Ecological Factors Impacting The Gulf Of Mexico Dead Zone, Jimmie Arnold Brumfield Ii Jan 2010

Dynamic Model Of Ecological Factors Impacting The Gulf Of Mexico Dead Zone, Jimmie Arnold Brumfield Ii

LSU Doctoral Dissertations

The industrial agriculture complex of the Mississippi River Drainage Basin has the positive effect of feeding more individuals with less land via the use of chemical nutrients, pesticides and drainage. The negative effects of the agricultural nutrient load are carried by the Mississippi River to the Gulf of Mexico. After the flood of 1927 the Flood Control Act of 1928 began changing the Mississippi River into a navigation and flood control project. While successful, the river was turned into a channel where nutrient input was discharged into the Gulf of Mexico. Nitrogen compounds discharged from the Mississippi are claimed to …


Study Of Microstructure Effect On The Thermal Properties Of Yttria-Stabilized-Zirconia Thermal Barrier Coatings Made By Atmospheric Plasma Spray And Pressing Machine, Monica Bohorquez De Silva Jan 2010

Study Of Microstructure Effect On The Thermal Properties Of Yttria-Stabilized-Zirconia Thermal Barrier Coatings Made By Atmospheric Plasma Spray And Pressing Machine, Monica Bohorquez De Silva

LSU Doctoral Dissertations

Thermal barrier coatings (TBCs) are used in gas turbine engines to achieve a higher working temperature and thus lead to better efficiency. Yttria-Stabilized-Zirconia (YSZ), a material with low thermal conductivity, is commonly used as the top coat layer to provide the thermal barrier effect. In this dissertation the thermo-physical properties of a variety of TBCs samples made out of different fabrication techniques were investigated and compared. The first set of samples was fabricated using a pressing machine device to fabricate 0.5 inch diameter disk shaped YSZ-Al2O3 samples. The YSZ-Al2O3 powder mixture was made of 0, 1, 2, 3, 4 and …


Lattice Boltzmann Modeling For Shallow Water Equations Using High Performance Computing, Kevin Tubbs Jan 2010

Lattice Boltzmann Modeling For Shallow Water Equations Using High Performance Computing, Kevin Tubbs

LSU Doctoral Dissertations

The aim of this dissertation project is to extend the standard Lattice Boltzmann method (LBM) for shallow water flows in order to deal with three dimensional flow fields. The shallow water and mass transport equations have wide applications in ocean, coastal, and hydraulic engineering, which can benefit from the advantages of the LBM. The LBM has recently become an attractive numerical method to solve various fluid dynamics phenomena; however, it has not been extensively applied to modeling shallow water flow and mass transport. Only a few works can be found on improving the LBM for mass transport in shallow water …


Experimental And Numerical Analysis Of Fuel Cells, Abul Bashar Mahmud Hasan Jan 2010

Experimental And Numerical Analysis Of Fuel Cells, Abul Bashar Mahmud Hasan

LSU Doctoral Dissertations

Fuel Cells are attractive power source for use in electronic applications. Physical phenomena (water generation, saturation effect in fuel cell, poisoning, and thermal stress) are studied that governs the operation of a Proton Exchange Membrane Fuel Cell (PEMFC) and Solid Oxide Fuel cell (SOFC). Additionally, experimental studies and numerical simulations on PEMFC gas flow channel, the determination of the impact of the single channel fuel cell are presented. Furthermore, preliminary study is done for the application of APS (Air Plasma Spray) to SOFC and adhesion of anode and cathode with electrolytes for the determination of parameters involved in manufacturing the …


Identifying And Quantifying Factors Affecting Traffic Crash Severity In Louisiana, Hong Zhang Jan 2010

Identifying And Quantifying Factors Affecting Traffic Crash Severity In Louisiana, Hong Zhang

LSU Doctoral Dissertations

This study was conducted to identify and quantify the factors affecting highway crash severity in Louisiana. Three candidate models were fit to the crash data to compare their performance and the Ordered Mixed Logit (OML) model was selected as the crash severity prediction model of choice. The factors contributing to crash severity identified by the OML model are: age and gender of the driver, vehicle speed, whether alcohol played a role in the crash, whether seatbelts were used, whether the driver was ejected from the vehicle, whether the crash was a head-on collision, whether an airbag was deployed, and whether …


Catalytic Oxidative Desulfurization Of A Model Diesel, Dongxing Liu Jan 2010

Catalytic Oxidative Desulfurization Of A Model Diesel, Dongxing Liu

LSU Major Papers

An analysis of heterogeneous oxidation catalysts was performed to determine the activities and optimal operating conditions for the multiphase oxidative desulfurization (ODS) reactions, using a model diesel. Catalysts studied included well-characterized Pd on Al2O3 and activated carbon supports, and carbon-supported Mo2C and W2C, which were prepared by temperature programmed reaction. Several other typical oxidation catalysts were also examined. The model diesel consisted of ~1 wt% sulfur compounds (thiophene and dibenzothiophene) with appropriate amounts of aliphatic, alkylaromatic and N-heterocyclic compounds to simulate a raw number 2 diesel. With oxygen as the oxidant in ODS reactions of this model diesel (70-90ºC, 0.8-1.8 …


A Study Of Hough Transform For Weld Extraction, Rakesh Gunaseelan Jan 2010

A Study Of Hough Transform For Weld Extraction, Rakesh Gunaseelan

LSU Master's Theses

The process of joining metals is called welding. At times, selecting a poor quality material or improper usage of welding technologies may cause defects in welded joints. Some of these welded joints have to be tested nondestructively, because their failure can cause lot of damage, for instance in power plants. Radiography is a very common method for non-destructive testing of welds. It is done by certified weld inspectors who have knowledge about weld flaws, looking at the radiograph of the welded joint with naked eye. The judgment of the weld inspector can be biased; subjective, because it is dependent on …


Caged Morpholino Oligonucleotide For Control Of Gene Expression In Zebrafish, Chad Michael Jarreau Jan 2010

Caged Morpholino Oligonucleotide For Control Of Gene Expression In Zebrafish, Chad Michael Jarreau

LSU Master's Theses

To control gene expression in vivo with spatial and temporal precision remains a significant hurdle in laboratory studies of development as well as clinical genetic therapies. Here we demonstrate such control over gene expression by use of photochemistry to reversibly inactivate the hybridization of a nucleic acid analog used for specific protein knockdown. A morpholino oligonucleotide, commonly used for knockdown of protein expression in developmental studies, was “caged” using carbodiimide conjugate chemistry which yielded photocleavable adducts that can be removed with light exposure. Photochemical inactivation approaches to produce caged molecules have been used to control the spatiotemporal activity of biomolecules …


Value-Added Processing Of Rice And Rice By-Products, Rebecca C. Schramm Jan 2010

Value-Added Processing Of Rice And Rice By-Products, Rebecca C. Schramm

LSU Doctoral Dissertations

World competition has encouraged United States rice farmers and rice mills to be efficient in farming and production practices. Efforts to augment economic competitiveness include development of new varieties, improvements in milling practices, and identification of uses for rice products and by-products. The research detailed in this dissertation adds to the body of knowledge in milling practices and identification of uses for rice bran. To improve the prediction of milled rice quality at industrial scale, correlations for milling quality among laboratory, pilot, and industrial scale mills were identified for Clearfield 161. Final industrial product whiteness was ten points higher than …


Experimental And Analytical Study Of The Surface Texturing Enhanced Lubrication Elements, Yifan Qiu Jan 2010

Experimental And Analytical Study Of The Surface Texturing Enhanced Lubrication Elements, Yifan Qiu

LSU Doctoral Dissertations

Surface texturing is a method that modifies the frictional surface of a nominally flat tribocomponent by shallow patterns. It is found that with added patterns to the surface of a mechanical face seal or thrust bearing, their tribological performance improves, i.e. both friction and wear rate decrease. The current research concentrates on the analysis of hydrodynamic effect responsible for the performance enhancement of the spiral groove patterns and dimples on mechanical seal-like structures and the experimental evaluation of the tribological behavior of these structures. Surface textures considered are: dimple texture and spiral groove pattern. In the research on the dimple …


Modeling And Simulation For Shape Memory Polymer Based Self-Healing Syntactic Foam, Wei Xu Jan 2010

Modeling And Simulation For Shape Memory Polymer Based Self-Healing Syntactic Foam, Wei Xu

LSU Doctoral Dissertations

Syntactic foams, renowned for their low density and high mechanical properties, are enjoying continuing growth in various civilian and military sectors. However, like laminated composites, foam cored structures are vulnerable to impact damages and suffering from inabilities in repairing macro-scale cracks. A self-healing mechanism for structural damage is genuinely desired. A recent development in self-healing structural damage is a two-step close then heal (CTH) scheme proposed by Li and Nettles [1] and elucidated by Li and Uppu [2], by mimicking the self-healing process of human skin. This concept has been further demonstrated in Nji and Li’s work [3] that a …


Transient Study Of The Wetting Films In Porous Media Using 3d X-Ray Computed Micro-Tomography: Effect Of Imbibition Rate And Pore Geometry, Pradeep Bhattad Jan 2010

Transient Study Of The Wetting Films In Porous Media Using 3d X-Ray Computed Micro-Tomography: Effect Of Imbibition Rate And Pore Geometry, Pradeep Bhattad

LSU Doctoral Dissertations

Imbibition in porous media is governed by the complex interplay between viscous and capillary forces, pore structure and fluid properties. Understanding and predicting imbibition is important in many natural and engineered applications; it affects the efficiency of oil production operations, the moisture and contaminant transport in soil science, and the formation of defects in certain types of composite materials. Majority of the studies published on the transient imbibition behavior in a porous medium were conducted in the simplified 2D transparent micromodels or the 2D projection visualization (X-ray or visible light) of the 3D porous medium. However, the pore level transient …


The Weakening Of Branch Predictor Performance As An Inevitable Side Effect Of Exploiting Control Independence, Christopher Joseph Michael Jan 2010

The Weakening Of Branch Predictor Performance As An Inevitable Side Effect Of Exploiting Control Independence, Christopher Joseph Michael

LSU Doctoral Dissertations

Many algorithms are inherently sequential and hard to explicitly parallelize. Cores designed to aggressively handle these problems exhibit deeper pipelines and wider fetch widths to exploit instruction-level parallelism via out-of-order execution. As these parameters increase, so does the amount of instructions fetched along an incorrect path when a branch is mispredicted. Many of the instructions squashed after a branch are control independent, meaning they will be fetched regardless of whether the candidate branch is taken or not. There has been much research in retaining these control independent instructions on misprediction of the candidate branch. This research shows that there is …


Parameterization Of Microwave Assisted Oil Extraction And Its Transesterification To Biodiesel, Akanksha V. Kanitkar Jan 2010

Parameterization Of Microwave Assisted Oil Extraction And Its Transesterification To Biodiesel, Akanksha V. Kanitkar

LSU Master's Theses

Currently, a majority of the world’s energy needs are met through use of fossil fuels, petroleum, coal and natural gas. The depletion of petroleum reserves, rising and extremely volatile crude oil prices, and environmental concerns have led to search for renewable and environmentally friendly fuels. The ultimate goal of this research was to develop, test and optimize a batch microwave system using traditional and alternate non-food feedstocks. Microwave assisted extraction (MAE) of oil from conventional feedstocks (soybeans and rice bran) and an alternative feedstock (Chinese tallow tree (CTT) seeds) was carried out. The study concluded that MAE of oil is …


Empirically Evaluating And Developing Alarm Rate Standards For Liquid Pipeline Control Room Operators, Glen David Uhack Ii Jan 2010

Empirically Evaluating And Developing Alarm Rate Standards For Liquid Pipeline Control Room Operators, Glen David Uhack Ii

LSU Master's Theses

The liquid and gas pipeline community has recently been faced with the challenge of new governmental regulations set forth by congress which are being implemented by PHMSA (an arm of the DOT). These new governmental regulations need to understand the role of the human in the loop as part of alarm management systems. To investigate alarm rate standards a repeated measures design was developed that included a series of ten (10) simulated liquid pipeline operator scenarios utilizing high fidelity liquid pipeline simulation software (Stoner Pipeline Simulator). A total of 39 participants volunteered for this study. Participants completed two subsets of …


Carbon Nanotube Interconnect Modeling For Very Large Scale Integrated Circuits, Yao Xu Jan 2010

Carbon Nanotube Interconnect Modeling For Very Large Scale Integrated Circuits, Yao Xu

LSU Doctoral Dissertations

In this research, we have studied and analyzed the physical and electrical properties of carbon nanotubes. Based on the reported models for current transport behavior in non-ballistic CNT-FETs, we have built a dynamic model for non-ballistic CNT-FETs. We have also extended the surface potential model of a non-ballistic CNT-FET to a ballistic CNT-FET and developed a current transport model for ballistic CNT-FETs. We have studied the current transport in metallic carbon nanotubes. By considering the electron-electron interactions, we have modified two-dimensional fluid model for electron transport to build a semi-classical one-dimensional fluid model to describe the electron transport in carbon …


Probabilistic Models For Short Term Traffic Conditions Prediction, Yan Qi Jan 2010

Probabilistic Models For Short Term Traffic Conditions Prediction, Yan Qi

LSU Doctoral Dissertations

Accurate short-term prediction of traffic condition on freeways and major arterials has become increasingly important because of its vital role in traffic management functions and various trip decisions. Given the dynamic nature of freeway traffic, this study proposed two stochastic model approaches, Hidden Markov Model (HMM) and One-Step Stochastic Model, for short-term traffic prediction during peak periods. The data used in the study are real-time traffic monitoring data gathered over 6 years on a 40-mile segment of Interstate-4 in Orlando, Florida. Both approaches are based on the traffic state transition probabilities. The HMM approach defines traffic states in a two …


Quantification Of Energy Intake Using Food Image Analysis, Sertan Kaya Jan 2010

Quantification Of Energy Intake Using Food Image Analysis, Sertan Kaya

LSU Master's Theses

Obtaining real-time and accurate estimates of energy intake while people reside in their natural environment is technically and methodologically challenging. The goal of this project is to estimate energy intake accurately in real-time and free-living conditions. In this study, we propose a computer vision based system to estimate energy intake based on food pictures taken and emailed by subjects participating in the experiment. The system introduces a reference card inclusion procedure, which is used for geometric and photometric corrections. Image classification and segmentation methods are also incorporated into the system to have fully-automated decision making.