Engineering Commons^™

Effects Of Processing Parameters On The Embrittlement Of Self Reacting Friction Stir Welds, David Eric Taylor

LSU Master's Theses

Friction Stir Welding (FSW) has been adopted as one of the major welding processes for joining Aluminum. Many aerospace and marine structures are welded through this novel FSW processes currently. The Lockheed Martin Space Systems (LMSS), Michoud Operations, in New Orleans is continuously pursuing Friction Stir Welding technologies in its efforts to advance fabrication of the external tanks of the space shuttle. Recently, a reduction in mechanical strength (embrittlement) has been observed especially in self-reacting (SR) friction stir welds. This strength reduction was attributed to Residual Oxide Defects (ROD) but the exact reasons for this type of behavior needed to …

Simulation Study Of Emerging Well Control Methods For Influxes Caused By Bottomhole Pressure Fluctuations During Managed Pressure Drilling, Hakan Guner

LSU Master's Theses

Managed Pressure Drilling (MPD) is an emerging drilling technology that utilizes mud weight, surface backpressure and annular frictional pressure loss (AFP) to precisely control the wellbore pressure. The goal of this project is to identify the most appropriate initial response and kick circulation method for the kicks that result from complications specific to MPD. These complications that can cause a reduction in bottomhole pressure were classified as surface equipment failures and unintended equivalent circulating density (ECD) reductions. Rotating control device (RCD) and pump failures are the examples of surface equipment failures. Pump efficiency loss and BHA position change represent the …

Particle-Chemical Interactions And Environmental Chemodynamics Of Fine And Ultrafine Particles In A Natural Disaster Scenario, Nicholas A. Ashley

LSU Doctoral Dissertations

The interactions of fine and ultrafine particles with chemicals play a dominant role in determining the mobility and availability of pollutants in the environment. Fine particles in sediments can sequester chemicals from the water column, and release volatile and semi-volatile organic compounds to the gas phase upon exposure to air. Ultrafine particles which are photoreactive can degrade these vapor-phase contaminants, and may transform the molecules into species which are more toxic or hazardous than the parent. As the widespread, commercial use of ultrafine particles becomes more common, understanding the chemodynamics of these particles and their interactions with chemicals in the …

The Fate And Transport Of Light Petroleum Hydrocarbons In The Lower Mississippi River Delta, Samantha Nicole Danchuk

LSU Doctoral Dissertations

Important processes governing the fate and transport of light petroleum hydrocarbons in the Lower Mississippi River and other river delta systems are not adequately represented in existing oil spill models. In response, three methods were introduced to include the effects of dynamic annual discharges and variation of shoreline type on shoreline retention and re-floatation and the potential of oil- mineral aggregate formation based contributing environmental factors. Parcel tracking was used, in conjunction with detailed shoreline types correlated to flow rate, to evaluate the benefits of using multiple shoreline re-floatation half lives correlated to shoreline type instead of a single half …

Compilation And Scheduling Techniques For Embedded Systems, Hassan Salamy

LSU Doctoral Dissertations

Embedded applications are constantly increasing in size, which has resulted in increasing demand on designers of digital signal processors (DSPs) to meet the tight memory, size and cost constraints. With this trend, memory requirement reduction through code compaction and variable coalescing techniques are gaining more ground. Also, as the current trend in complex embedded systems of using multiprocessor system-on-chip (MPSoC) grows, problems like mapping, memory management and scheduling are gaining more attention. The first part of the dissertation deals with problems related to digital signal processors. Most modern DSPs provide multiple address registers and a dedicated address generation unit (AGU) …

Impact Of Watershed Delineation Detail On Hydrologic Process Modeling In Low Slope Areas, Jason Alexander Braud

LSU Master's Theses

Ascension Parish, located along the Mississippi River in southern Louisiana, is a low-lying, low slope landscape that primarily drains into the tidally-influenced Lake Maurepas. The predominant method of drainage within the parish is gravity drainage. Ascension Parish is currently one of the fastest growing areas in the United States. New developments have changed the area’s hydrology along with its landscape. Proper watershed delineation within the parish is critical for the management of and future improvements to the parish’s drainage infrastructure. Most of the recent drainage modeling in the parish has been performed using a light detection and ranging (LIDAR) digital …

Freeway Crash And Lane Compliance Under Truck Lane Restriction And Differential Speed Limit, Murat Korkut

LSU Master's Theses

In the last decade, several fatal truck related crashes occurred on the elevated freeway over the Atchafalaya Basin. In an attempt to reduce the crash rates, the Louisiana Department of Transportation and Development implemented two policies to regulate the truck traffic on this rural divided freeway that has two lanes in each direction of flow. These policies restricted truck traffic to the right lane and reduced the maximum truck speed limit to 55-mph. On the other hand, maximum car speed limit was kept at 60-mph. The changes took place in 2003. While the policies were in effect, crash and traffic …

Pore-Scale Analysis Of Dnapl Dissolution And Biomass Distribution, Keegan L. Roberts

LSU Doctoral Dissertations

A comparison of equilibrium and non-equilibrium dissolution of tetrachloroethylene (PCE) was conducted to ascertain how PCE saturation, individual blob properties (volume, surface area, sphericity), and PCE occupied pores are affected by two distinct dissolution regimes. One-dimensional columns were imaged at various dissolution stages using high resolution (~10 um) synchrotron x-ray tomography (XT) and image subvolumes were analyzed using a series of grain, pore network structure, and blob analysis algorithms. An analysis of algorithm-generated data was conducted to determine grain and pore statistics, PCE saturation and individual blob properties, and correlations between PCE blobs and pore network structure. Grain and pore …

Asynchronous Replication Of Metadata Across Multi-Master Servers In Distributed Data Storage Systems, Ismail Akturk

LSU Master's Theses

In recent years, scientific applications have become increasingly data intensive. The increase in the size of data generated by scientific applications necessitates collaboration and sharing data among the nation's education and research institutions. To address this, distributed storage systems spanning multiple institutions over wide area networks have been developed. One of the important features of distributed storage systems is providing global unified name space across all participating institutions, which enables easy data sharing without the knowledge of actual physical location of data. This feature depends on the ``location metadata'' of all data sets in the system being available to all …

Numerical Investigation Of Film Cooling Fluid Flow And Heat Transfer Using Large Eddy Simulations, David Houston Leedom

LSU Master's Theses

Large eddy simulations of film cooling from discrete holes inclined at 35° with a feeding plenum chamber are performed at a density ratio of 2 and blowing ratios from 0.5 to 2.0 in order to gauge the suitability and performance of different hole shapes. Cylindrical holes at length to diameter ratios of 1.75 and 3.5 as well as shaped holes (laterally diffused and console holes) at a length to diameter ratio of 3.5 are simulated issuing into a laminar crossflow at a Reynolds number of approximately 16,000 based on freestream velocity and hole diameter. The domain extends 15 hole diameters …

Functionally Gradient Syntactic Foams, Kanakaji Chittineni

LSU Master's Theses

Syntactic foams are comprised of hollow microballoons in matrix systems. The superior mechanical and physical properties of syntactic foams such as light weight, high compressive strength, and low moisture absorption make them attractive materials for structural applications. As these materials are used in high mechanical performance applications, there is a need to achieve both high compressive strength and high energy absorption with minimal or no increase in density. In this study, the effect of gradient configuration of syntactic foams on the energy absorption and compressive strength is studied. Functionally Gradient Syntactic Foams (FGSFs) in five different layer sequencings are fabricated …

Sophisticated Denial-Of-Service Attack Detections Through Integrated Architectural, Os, And Appplication Level Events Monitoring, Ran Tao

LSU Master's Theses

As the first step to defend against DoS attacks, Network-based Intrusion Detection System is well explored and widely used in both commercial tools and research works. Such IDS framework is built upon features extracted from the network traffic, which are application-level features, and is effective in detecting flooding-based DoS attacks. However, in a sophisticated DoS attack, where an attacker manages to bypass the network-based monitors and launch a DoS attack locally, sniffer-based methods have difficulty in differentiating attacks with normal behaviors, since the malicious connection itself behaves in the same manner of normal connections. In this work, we study a …

Investigation Into The Hydrothermal Treatment Of Sugarcane Bagasse Under Near- And Supercritical Conditions, John E. White

LSU Doctoral Dissertations

Processing biomass in near- and supercritical water has garnered increasing attention because of its ability to accept a variety of wet feedstocks, energy efficiency, and ability to regulate the solubility and separation of components. Very few studies of biomass hydrothermal conversion provide a comprehensive evaluation of multiple process parameters and various additives and their effects on a single product phase. This research examined the influence of temperature, residence time, biomass concentration, and particle size on volatiles production from the hydrothermal conversion of sugarcane bagasse. Temperature had the greatest impact on volatile yields with the largest increase (23 wt %) occurring …

Integrated Model-Centric Decision Support System For Process Industries, Daira Aragon

LSU Doctoral Dissertations

To bring the advances in modeling, simulation and optimization environments (MSOEs), open-software architectures, and information technology closer to process industries, novel mechanisms and advanced software tools must be devised to simplify the definition of complex model-based problems. Synergistic interactions between complementary model-based software tools must be refined to unlock the potential of model-centric technologies in industries. This dissertation presents the conceptual definition of a single and consistent framework for integrated process decision support (IMCPSS) to facilitate the realistic formulation of related model-based engineering problems. Through the integration of data management, simulation, parameter estimation, data reconciliation, and optimization methods, this framework …

Photocatalytic Reaction In Monolithic Optical Fiber Reactor With Inverse Opal Catalyst, Maoming Ren

LSU Doctoral Dissertations

The development of photocatalytic reactor is essential for the successful application of heterogeneous semiconductor in environmental study, which has been shown to be photoactive and effective to oxidate organic pollutant and photoreduce CO2 to useful compounds. In this dissertation, a monolithic optical fiber reactor (MOFR) coated with inverse opal titania, which uses optical fibers as light-transmitting conductor and support of catalyst, was developed for both photodegradation and photoreduction. 1,2-dichlorobenzene, a volatile organic compound (VOC), was selected as the organic pollutant. This configuration of reactor and catalyst provides a high surface area, enhances mass transfer within the catalyst, manipulates photons transmission …

A Multi-Function, Disposable, Microfluidic Module For Mutation Detection, Tae Yoon Lee

LSU Doctoral Dissertations

Recognition of point mutations in a codon 12 of the K-ras gene, most frequently observed, is considered to be useful in the early diagnosis of several types of the human cancers. We have developed a multifunction, disposable, microfluidic module which detects low-abundant point mutations in human genomic DNA in modular architecture. Each functional component including a microfluidic PCR reactor, a passive diffusional micromixer reactor, and a microfluidic LDR reactor was separately designed and fabricated. Fluidic interconnects were also developed to make a fluidic passage between the functional components. Polycarbonate substrates were micro-molded, using hot embossing with micro-milled brass mold inserts …

System Identification Of Bridge And Vehicle Based On Their Coupled Vibration, Lu Deng

LSU Doctoral Dissertations

Most current techniques used for system identification of bridges and vehicles are static-test-based methods. Methodologies that can use bridge dynamic responses or modal information are highly desirable and under development. This dissertation aims to develop new identification methodologies for bridge-vehicle systems using the bridge dynamic responses and modal information. A new bridge model updating method using the response surface method (RSM) was proposed in this dissertation. The RSM was used to design experiments in order to find out the relationships between the bridge responses and parameters to be updated. Results from numerical simulations and a field study show that the …

Physical Layer Security In Wireless Networks: Intelligent Jamming And Eavesdropping, George Traian Amariucai

LSU Doctoral Dissertations

This work aims at addressing two critical security issues residing in the physical layer of wireless networks, namely intelligent jamming and eavesdropping. In the first two chapters we study the problem of jamming in a fixed-rate transmission system with fading, under the general assumption that the jammer has no knowledge about either the codebook used by the legitimate communication terminals, or the source’s output. Both transmitter and jammer are subject to power constraints which can be enforced over each codeword (peak) or over all codewords (average). All our jamming problems are formulated as zero-sum games, having the probability of outage …

Sialic Acid Conjugated Chitosan For The Attenuation Of Amyloid-Beta Toxicity, Dhruva Dilip Dhavale

LSU Master's Theses

Amyloid-beta (Aβ), a 39 to 43 amino acid long peptide, is the primary species identified in senile plaques associated with Alzheimer’s disease (AD) and has been implicated in the neurotoxicity associated with AD. It is believed that Aβ toxicity is mediated through the interaction with neuronal membranes. A variety of evidence indicates that 1) Aβ may bind to the cell surface sialic acids, 2) the affinity of this interaction is higher if the gangliosides or sialic acids on the cell surface are clustered, 3) the removal of the surface sialic acids attenuate Aβ toxicity. Based on this data, we hypothesized …

Intracellular Ice Formation In Adult Stem Cells In The Presence Of Polyvinyl Pyrrolidone, Avishek Guha

LSU Master's Theses

The main objective of this work was to assess the effect of 10% (w/v) polyvinylpyrrolidone (PVP) on the pattern of intracellular ice formation (IIF) in human adipose tissue derived adult stem cells (ASCs) in the absence of serum and other cryoprotective agents (CPAs). Passage 1 (P1) ASCs were cultured, washed and suspended in either 1x PBS (Phosphate Buffered Saline) or 10% w/v solution of PVP in 1x PBS. The freezing experiments were carried out using a fluorescence microscope equipped with a Linkam™ cooling stage using two different temperature/time cooling protocols. Both the cooling protocols had a common cooling ramp: cells …

The Modification, System Software Development, Validation, And Clinical Trial Of A Novel Ankle Stiffness Testing Device, T. Tyler Clement

LSU Master's Theses

The purpose of this project is to modify, validate, and gather preliminary clinical data on a novel ankle stiffness device that measures stiffness (torque / degree) and range of motion (ROM) of the ankle joint complex (AJC). The initial device was designed by a mechanical engineering design group at Louisiana State University in 2006, but had not been tested on human participants. Clinical evaluation of the ankle joint is important in patients afflicted with diabetes mellitus, Hansen’s disease, or peripheral neuropathies. The combination of peripheral neuropathies, decreased ankle range of motion, and increased stiffness pose a threat to these patients, …

A Modular Approach To High Throughput Microsystems, Pin-Chuan Chen

LSU Doctoral Dissertations

A modular high throughput microsystem was developed using microfabrication technology and nucleic acid analysis. The purpose of developing this microsystem is to identify acute infectious disease and prevent contagious outbreak in a matter of time. This microsystem included three major components, a reagent distribution device, a 96 CFPCR array, and a multi-zone thermal system, to efficiently amplify specific DNA fragments to determine the disease status or precisely pinpoint a disease from multiple patients. Polymerase chain reaction (PCR) is the key component in the nucleic acid analysis for disease because it can be used to amplify interested DNA fragments by repeatedly …

Aerodynamic And Heat Transfer Studies In A Combustor-Fired, Fixed-Vane Cascade With Film Cooling, James William Post

LSU Master's Theses

Pressure and heat transfer data has been generated in a high-pressure, high-temperature vane cascade. This cascade differs from many others seen in typical low-pressure facilities using room temperature air. Primarily, a natural gas-fired combustor generates realistic turbulence profiles in the high-temperature exhaust gases that pass through the vane cascade. The fixed-vane cascade test sections have film cooling holes machined into the surfaces in arrangements that closely model configurations seen in real-life first-row nozzle guide vanes (NGV). Theoretical coolant jet-to-crossflow blowing ratios (M) range from 0.5 to 3.0. Coolant jet-to-crossflow theoretical density ratios (DR) used for typical tests vary between 1.0 …

Thermomechanical Characterization Of A Shape Memory Polymer Based Syntactic Foam, Damon Nettles

LSU Master's Theses

Shape memory polymers (SMPs) are a type of smart material capable of “remembering” multiple shapes and transitioning between them in response to an external stimulus. They offer the potential to self-seal macro-length scale damage in a nearly autonomous fashion. Syntactic foams are lightweight structural materials currently used in the marine and aerospace industries. This study seeks to bring syntactic foams and SMPs together, retaining characteristics of both components, to create a low-density smart composite. The SMP based syntactic foam is used as the core of a grid stiffened sandwich structure capable of healing impact damage multiple times. In order to …

Fabrication, Bonding, Assembly, And Testing Of Metal-Based Microchannel Devices, Fanghua Mei

LSU Doctoral Dissertations

Microsystem technologies are believed to be an important part of the contemporary technological foundation and are becoming a commercially significant specialty area in manufacturing. The design and fabrication of microscale engineering structures has the potential of generating revolutionary changes in many products over a wide range of industrial sectors. Metal-based microchannel heat exchangers (MHEs) promise high heat transfer coefficients together with mechanical robustness, and are of interest for a wide range of applications. Fabrication technologies capable of creating high-aspect-ratio microscale structures (HARMSs) in metals such as Cu at low cost and high throughput are of particular interest. Likewise, simple and …

A Non-Invasive Semiconductor Optical System To Measure Skin Tension, Anna Charron Dugas

LSU Master's Theses

The objectives of this project are to design, construct, validate and test a low-cost, non-invasive and painless device to measure skin tension. Skin is a complex, multi-layered, anisotropic material with non-linear viscoelastic behavior during stress application. The intricate balance of different semi-elastic fibers and continuous regeneration has brought difficulty to the accurate measurement of its mechanical properties. Commercial skin tension measurement products have been described, but are too expensive to be readily accessible for skin research and clinical utilization. The device to be developed in this project differs from existing devices in that it measures skin deformation under vacuum using …

The Price Of Stability In Selfish Scheduling Games, Lucas Agussurja, Hoong Chuin Lau

Research Collection School Of Computing and Information Systems

Game theory has gained popularity as an approach to analysing and understanding distributed systems with self-interested agents. Central to game theory is the concept of Nash equilibrium as a stable state (solution) of the system, which comes with a price − the loss in efficiency. The quantification of the efficiency loss is one of the main research concerns. In this paper, we study the quality and computational characteristics of the best Nash equilibrium in two selfish scheduling models: the congestion model and the sequencing model. In particular, we present the following results: (1) In the congestion model: first, the best …

Mathematical Models For Natural Gas Forecasting, Steven Vitullo, Ronald H. Brown, George F. Corliss, Brian M. Marx

Electrical and Computer Engineering Faculty Research and Publications

It is vital for natural gas Local Distribution Companies (LDCs) to forecast their customers' natural gas demand accurately. A significant error on a single very cold day can cost the customers of the LDC millions of dollars. This paper looks at the financial implication of forecasting natural gas, the nature of natural gas forecasting, the factors that impact natural gas consumption, and describes a survey of mathematical techniques and practices used to model natural gas demand. Many of the techniques used in this paper currently are implemented in a software GasDay^TM, which is currently used by 24 LDCs …

A Pilot Study Evaluating Use Of A Computer-Assisted Neurorehabilitation Platform For Upper-Extremity Stroke Assessment, Xin Feng, Jack Winters

Electrical and Computer Engineering Faculty Research and Publications

Background

There is a need to develop cost-effective, sensitive stroke assessment instruments. One approach is examining kinematic measures derived from goal-directed tasks, which can potentially be sensitive to the subtle changes in the stroke rehabilitation process. This paper presents the findings from a pilot study that uses a computer-assisted neurorehabilitation platform, interfaced with a conventional force-reflecting joystick, to examine the assessment capability of the system by various types of goal-directed tasks.

Methods

Both stroke subjects with hemiparesis and able-bodied subjects used the force-reflecting joystick to complete a suite of goal-directed tasks under various task settings. Kinematic metrics, developed for specific …

Engineering Of A Single Alkaline Fuel Cell Part Ii: Long Term Operation In Air, Jonathan Blackledge, Eugene Coyle, David Kennedy, Heinz Schmidt-Walter, Hans Kohnke, Steffen Schudt, Gerhard Sauer, James Hamilton

Articles

Research into renewable energy sources has previously lacked sufficient investment. However, emphasis has now shifted and funding is being made available in a proactive manner by various governments eager to encourage renewable energy technology and reduce carbon taxes. Fuel Cells offer a realistic, sustainable and clean alternative energy option for stationary and mobile applications. Hydrogen and fuel cell technologies are recognised by many as possible long term energy solutions, but to-date, have failed to make an impact on the energy market. This is due to a number of key reasons, some of which include efficiency, scale, accessories and power output. …