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Articles 1 - 30 of 146
Full-Text Articles in Engineering
Microfluidics Fabrication And Testing For A Novel Biomems Cell Counting Device, Marly N. Dows
Microfluidics Fabrication And Testing For A Novel Biomems Cell Counting Device, Marly N. Dows
Honors Theses
No abstract provided.
Damage Mechanics Of Composite Materials Using Fabric Tensors, Ziad N. Taqieddin
Damage Mechanics Of Composite Materials Using Fabric Tensors, Ziad N. Taqieddin
LSU Master's Theses
The major objective of this work is to relate continuum damage mechanics introduced through the concept of fabric tensors to composite materials within the framework of classical elasticity theory. A model of directional data-damage mechanics for composite materials is formulated using fabric tensors. In addition, a general hypothesis for damage mechanics is postulated. It is seen that the two available hypotheses of elastic strain equivalence and elastic energy equivalence may be obtained as special cases of the postulated general hypothesis. This general hypothesis is then used to derive the sought relationship between the damage tensor for composite materials and the …
Experimental And Numerical Study Of Feeding Channel In Proton Exchange Membrane Fuel Cell, Abul Bashar Mahmud Hasan
Experimental And Numerical Study Of Feeding Channel In Proton Exchange Membrane Fuel Cell, Abul Bashar Mahmud Hasan
LSU Master's Theses
The performance of a Proton Exchange Membrane Fuel Cell (PEMFC) using different feeding configurations has been studied, with a focus on the water flooding due to electrochemical reaction. Feeding channel or Bipolar plate in Proton Exchange Fuel Cell is a dominating part. As feeding channel keeps direct contact with the gas diffusion layer, it helps efficiently supplying fuel and air into the gas diffusion layer for efficient production of electricity. Experimental data have been taken at hydrogen flow rates of 20,40,60,80,100 sccm for various bipolar plate arrangements. Three bipolar plates, namely serpentine, straight channel and interdigitated designs, were arranged in …
Thermal Management Of The Lsu Micro Gas Chromatograph, Praveen K. Pasupuleti
Thermal Management Of The Lsu Micro Gas Chromatograph, Praveen K. Pasupuleti
LSU Master's Theses
Gas chromatography is a technique widely used for the separation and analysis of gas samples. Gas chromatographs are used for environmental maintenance, monitoring sophisticated biological analyses, and to separate components from a mixture of gases for mass spectrometer analysis. There has been a tremendous interest in miniaturization of gas chromatograph systems because of the potential for portability, faster response time, lower dead volume, lower power consumption, and lower cost of operation. Conventional gas chromatography keeps the column at a constant temperature during separation, which is called isothermal analysis. Temperature programming is a mode of gas chromatography in which the column …
Distributed Airlift Systems Design With Application To Recirculating Soft Shell Crawfish Shedding Systems, Sripavani Gudipati
Distributed Airlift Systems Design With Application To Recirculating Soft Shell Crawfish Shedding Systems, Sripavani Gudipati
LSU Master's Theses
Soft shell crawfish, a seafood delicacy, has a potential market for growth in the aquaculture industry. Since the industry's collapse in the 1990's, the advent of new technologies like eyestalk ablation, automated hydraulic separation and distributed airlift systems has elevated the hope for restoration. In a distributed airlift system, airlifts and distribution pipes supply water to holding trays. Airlifts are simple devices used to pump water by injecting air at the bottom of an open pipe. The combination of airlifts and distribution pipes has potential economic benefits for low head applications in recirculating aquaculture systems. This thesis focuses on guidelines …
Simulations And Experimental Analysis Of High-Aspect-Ratio Diffusive Micro-Mixers, Amit Maha
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 …
Deposition Of Carbon Layers From Cyclohexane By Thermal Chemical Vapor Deposition, Bharath Thiruvengadachari
Deposition Of Carbon Layers From Cyclohexane By Thermal Chemical Vapor Deposition, Bharath Thiruvengadachari
LSU Master's Theses
The overall aim of this thesis is to deposit carbon layers by thermal Chemical Vapor Deposition (CVD) and investigate the effects of process parameters on the morphology and structure of the deposited carbon layers. Cyclohexane (C6H12) hydrocarbon is the precursor material used as the source of carbon. A 20% Cu- 80% Ni alloy, deposited by RF magnetron sputtering and annealed at the growth temperature either in an argon flow or in 10% hydrogen-90% argon flow, is used as a catalyst prior to carbon film deposition by CVD. The CVD temperature is varied between 550 0C and 800 0C. The Cu-Ni …
Functionalization Of Gold And Glass Surfaces With Magnetic Nanoparticles Using Biomolecular Interactions, Bala Sesha Giri Rao Nidumolu
Functionalization Of Gold And Glass Surfaces With Magnetic Nanoparticles Using Biomolecular Interactions, Bala Sesha Giri Rao Nidumolu
LSU Master's Theses
Advances in nanotechnology have enabled the production and characterization of magnetic particles with nanometer-sized features that can be functionalized with biological recognition elements for clinical and biosensing applications. In the present study the synthesis and interactions between self assembled monolayers (SAMs) and functionalized nanoparticles have been characterized. Size and shape of magnetic nanoparticles synthesized wet chemically starting from ferrous and ferric salts were verified by transmission electron microscopy (TEM). These nanoparticles were then conjugated with FITC-labeled streptavidin through carbodiimide (EDC) chemistry. SAMs of thiol-capped biotins were synthesized on gold surfaces for capture of the conjugated nanoparticles. Characterization of nanoparticle functionalization …
Experimental Investigation Of Drilling Fluid Formulations And Processing Methods For A Riser Dilution Approach To Dual Density Drilling, John Shelton
LSU Master's Theses
Oil and natural gas resources in the deepwater Gulf of Mexico are important for the U.S. economy, but development is limited by high costs. Dual density drilling concepts that result in wellbore pressure gradients similar to the natural subsurface gradients can simplify well designs and reduce costs. Riser dilution may be an economical means of achieving such a system. This system would use a low density fluid to dilute the weighted wellbore fluid and give an intermediate density fluid in the riser. Two key concerns addressed in this study are whether a drilling fluid can be formulated that will suspend …
Cognitive Memory Effects On Non-Linear Video-Based Learning, Katherine Renee Comeaux
Cognitive Memory Effects On Non-Linear Video-Based Learning, Katherine Renee Comeaux
LSU Master's Theses
During an informative learning process, information, material, facts and ideas are typically conveyed in a linear arrangement. Individuals are frequently distracted during this process with their attention being diverted to an interruption (Internet, phone call, etc). When presented with any new information, the mind evolves through problem solving and evaluation procedures. The way in which that information is processed and perceived depends on: (a) original presentation (b) examination of material and (c) an individualistic measurement of success. However, when faced with an interruption, the person is forced to deal with non-linear arrangement of information. This research investigates nonlinear presentation or …
Geostatistical Integration Of Geophysical, Well Bore And Outcrop Data For Flow Modeling Of A Deltaic Reservoir Analogue, Hong Tang
LSU Doctoral Dissertations
Significant world oil and gas reserves occur in deltaic reservoirs. Characterization of deltaic reservoirs requires understanding sedimentary and diagenetic heterogeneity at the submeter scale in three dimensions. However, deltaic facies architecture is complex and poorly understood. Moreover, precipitation of extensive calcite cement during diagenesis can modify the depositional permeability of sandstone reservoir and affect fluid flow. Heterogeneity contributes to trapping a significant portion of mobile oil in deltaic reservoirs analogous of Cretaceous Frontier Formation, Powder River Basin, Wyoming. This dissertation focuses on 3D characterization of an ancient deltaic lobe. The Turonian Wall Creek Member in central Wyoming has been selected …
Experimental Quantification And Dem Simulation Of Micro-Macro Behaviors Of Granular Materials Using X-Ray Tomography Imaging, Yanrong Fu
LSU Doctoral Dissertations
A non-invasive experimental method and a clustering DEM model were developed in this study to investigate micro-macro behaviors of real granular materials with irregular particle shape configurations. The investigated behaviors include global deformations, failure strengths and residual strengths, stress and strain distributions, local coordination number, local void ratio, particle kinematics, and fabric orientation distributions. The experimental method includes an approach to automatically identify and recognize multiple particles using x-ray computed tomography imaging (XCT) and an enhanced approach to digitally represent microstructures of granular materials. The digitally represented microstructure can be directly employed for numerical simulation setup. A compression test and …
Development Of High Performance Hybrid Syntactic Foams: Structure And Material Property Characterization, Rahul R. Maharsia
Development Of High Performance Hybrid Syntactic Foams: Structure And Material Property Characterization, Rahul R. Maharsia
LSU Doctoral Dissertations
Syntactic foams are light weight particulate composites that use hollow particles (microballoons) as reinforcement in a polymer resin matrix. High strength microballoons provide closed cell porosity which helps in reducing weight of the material. Due to their wide range of possible applications such as in aerospace and marine structures, it is desirable to modify the physical and mechanical properties of syntactic foams as per the requirements of an application. Various filler materials can be used to modify the foam microstructure to attain these desired properties. Compression tests have revealed that high density syntactic foams demonstrate poor damage tolerance and low …
Fabrication Of High Aspect Ratio Vibrating Cylinder Microgyroscope Structures By Use Of The Liga Process, Yohannes Mamo Desta
Fabrication Of High Aspect Ratio Vibrating Cylinder Microgyroscope Structures By Use Of The Liga Process, Yohannes Mamo Desta
LSU Doctoral Dissertations
Inertial grade microgyroscopes are of great importance to improve and augment inertial navigation systems based on GPS for industrial, automotive, and military applications. The efforts by various research groups worldwide to develop inertial grade microgyroscopes have not been successful to date. In 1994, the Department of Mechanical Engineering at Louisiana State University and SatCon Technology Corporation (Boston, Massachusetts) proposed a series of shock tolerant micromachined vibrating cylinder rate gyroscopes with aspect ratios of up to 250:1 to meet the needs of inertial navigation systems based on existing conventional vibrating cylinder gyroscopes. Each microgyroscope consisted of a tall thin shell metallic …
An Application Of Parallel Computation To Collaborative Optimization, Shahab Nayyer
An Application Of Parallel Computation To Collaborative Optimization, Shahab Nayyer
LSU Master's Theses
Multidisciplinary Design Optimization (MDO) has evolved as a discipline which provides a body of methods and techniques to assist engineers in solving large scale design problems. There are many frameworks for formulating MDO problems. These frameworks can be broadly classified as single-level or bi-level formulations. Collaborative Optimization (CO) is one of the popular bi-level formulations to solve an MDO problem. There are numerous design optimization problems which are highly CPU time intensive and require a long simulation time. With the advent of cheaper and faster available PC’s, distributed parallel computer clusters have become very popular. These clusters provide large computing …
Electrodeposition Of Magnetic Nanowires And Nanotubes, Despina Mehedintu Davis
Electrodeposition Of Magnetic Nanowires And Nanotubes, Despina Mehedintu Davis
LSU Master's Theses
The current perpendicular to the plane giant magneto-resistance (CPP)-(GMR) effect makes multilayered nanowires of huge interest as magnetic sensor materials. GMR showing multilayer nanostructures are composed of alternating ferromagnetic and nonmagnetic nanometric layers. The giant magnetoresistance (GMR) property is described as a change in electrical resistance when an external magnetic field is introduced. Electrodeposition is the most efficient method for fabricating magnetic nanowires. In addition to the cost-effectiveness, electrodeposition is one of the few methods that can overcome the geometrical restrictions of inserting metals into very deep nanometric recesses, making it the favored method for nanowire and nanotube fabrication. In …
Multivariate Hydrological Frequency Analysis And Risk Mapping, Lan Zhang
Multivariate Hydrological Frequency Analysis And Risk Mapping, Lan Zhang
LSU Doctoral Dissertations
In hydrological frequency analysis, it is difficult to apply standard statistical methods to derive multivariate probability distributions of the characteristics of hydrologic or hydraulic variables except under the following restrictive assumptions: (1) variables are assumed independent, (2) variables are assumed to have the same marginal distributions, and (3) variables are assumed to follow or are transformed to normal distribution. Relaxing these assumptions when deriving multivariate distributions of the characteristics of correlated hydrologic and hydraulic variables. The copula methodology is applied to perform multivariate frequency analysis of rainfall, flood, low-flow, water quality, and channel flow, using data from the Amite river …
Interference Suppression And Parameter Estimation In Wireless Communication Systems Over Time-Varing Multipath Fading Channels, Jianqiang He
Interference Suppression And Parameter Estimation In Wireless Communication Systems Over Time-Varing Multipath Fading Channels, Jianqiang He
LSU Doctoral Dissertations
This dissertation focuses on providing solutions to two of the most important problems in wireless communication systems design, namely, 1) the interference suppression, and 2) the channel parameter estimation in wireless communication systems over time-varying multipath fading channels. We first study the interference suppression problem in various communication systems under a unified multirate transmultiplexer model. A state-space approach that achieves the optimal realizable equalization (suppression of inter-symbol interference) is proposed, where the Kalman filter is applied to obtain the minimum mean squared error estimate of the transmitted symbols. The properties of the optimal realizable equalizer are analyzed. Its relations with …
Thermo And Kinetic Studies On The Sorption And Desorption Of Hydrophobic Organic Contaminants In Sediments, Yunzhou Chai
Thermo And Kinetic Studies On The Sorption And Desorption Of Hydrophobic Organic Contaminants In Sediments, Yunzhou Chai
LSU Doctoral Dissertations
This study investigated the correlation of desorption resistance of hydrophobic organic contaminants (HOCs) in sediment and the heterogeneity of sediment organic matter (SOM). The amorphous and condensed phase organic carbon contents were defined by the method of Gustafsson et al. (1997) using thermal oxidation of sediment under 375°C. The desorption-resistant fraction of contaminants in sediments was operationally defined as the fraction that could not be removed by the adsorbent XAD-2. The correlation of the desorption-resistant fraction with sediment organic carbon characteristics was evaluated for both laboratory-inoculated and field-contaminated sediments. No strong correlation between the desorption resistant fraction in laboratory-inoculated sediments …
Cementitious Permeable Pavement As A Passive Unit Operation And Process For Stormwater Quality And Quantity Control, Xuheng Kuang
Cementitious Permeable Pavement As A Passive Unit Operation And Process For Stormwater Quality And Quantity Control, Xuheng Kuang
LSU Doctoral Dissertations
With respect to the problems caused by impervious pavements, cementitous permeable pavement (CPP) functions as a passive unit operation and process for stormwater quality and quantity control through infiltration, evaporation, filtration, absorption and reaction mechanisms. CPP pore characteristics were examined through pore connectivity analysis using X-Ray Tomography (XRT). Image resolution influence on image analysis results was evaluated. Relationships between parameters of pore characteristics were evaluated. Factors that significantly influence fluid flow in CPP media include effective porosity, pore connectivity and pore size distribution. A modified Kozeny-Carman model in which effective porosity, specific surface area based on effective pores (SSA)pe, and …
Shaly Sand Interpretation Using Cec-Dependent Petrophysical Parameters, Fnu Kurniawan
Shaly Sand Interpretation Using Cec-Dependent Petrophysical Parameters, Fnu Kurniawan
LSU Doctoral Dissertations
This research explores the characterization of petrophysical parameters such as cementation exponent, saturation exponent and effective porosity as a function of cations exchange capacity (CEC), and its impact on shaly sand interpretation. Experimental and field data were used in the study. The latest LSU model for shaly sand interpretation uses of two cementation exponents, mf and mc, to represent the tortuosity of electric current path in free water and clay bound water, respectively. Experimental measurements on three types of rock, clean sand, shaly sand and pure shale using different brine salinity, were conducted to validate the use of these two …
Power And Memory Optimization Techniques In Embedded Systems Design, Atef Khalil Allam
Power And Memory Optimization Techniques In Embedded Systems Design, Atef Khalil Allam
LSU Doctoral Dissertations
Embedded systems incur tight constraints on power consumption and memory (which impacts size) in addition to other constraints such as weight and cost. This dissertation addresses two key factors in embedded system design, namely minimization of power consumption and memory requirement. The first part of this dissertation considers the problem of optimizing power consumption (peak power as well as average power) in high-level synthesis (HLS). The second part deals with memory usage optimization mainly targeting a restricted class of computations expressed as loops accessing large data arrays that arises in scientific computing such as the coupled cluster and configuration interaction …
Stability, Transport And Applications Of Polyaphrons In Porous Media, Le Yan
Stability, Transport And Applications Of Polyaphrons In Porous Media, Le Yan
LSU Doctoral Dissertations
Polyaphrons are a kind of macroemulsion. The most distinctive feature of polyaphrons is their high stability. On the other hand, certain polyaphrons can be effectively destabilized by multivalent ions. In this dissertation, we devise a novel procedure that utilizes the fact that polyaphrons can be destabilized by certain ions to deliver light chemicals to lower the density of dense non-aqueous phase liquid (DNAPL) contaminants in situ. We first investigate how the stability of diluted polyaphrons is affected by the properties of the continuous phase. We find that polyaphrons can be destabilized by a low concentration of Al3+ or Ca2+ in …
Physically Based Multiscale-Viscoplastic Model For Metals And Steel Alloys: Theory And Computation, Farid H. Abed
Physically Based Multiscale-Viscoplastic Model For Metals And Steel Alloys: Theory And Computation, Farid H. Abed
LSU Doctoral Dissertations
The main requirement of large deformation problems such as high-speed machining, impact, and various primarily metal forming, is to develop constitutive relations which are widely applicable and capable of accounting for complex paths of deformation. Achieving such desirable goals for material like metals and steel alloys involves a comprehensive study of their microstructures and experimental observations under different loading conditions. In general, metal structures display a strong rate- and temperature-dependence when deformed non-uniformly into the inelastic range. This effect has important implications for an increasing number of applications in structural and engineering mechanics. The mechanical behavior of these applications cannot …
Laterally Movable Gate Field Effect Transistor (Lmgfet) For Microsensor And Microactuator Applications, In-Hyouk Song
Laterally Movable Gate Field Effect Transistor (Lmgfet) For Microsensor And Microactuator Applications, In-Hyouk Song
LSU Doctoral Dissertations
Laterally Movable Gate Field Effect Transistor (LMGFET) invented at LSU as a microactuator is the subject of study in this research. The gate moving in lateral direction in a LMGFET changes channel width but keeps the channel length and the gap between the metal gate and the gate oxide constant. LMGFET offers linear change in drain current with gate motion and a large displacement range. This research is the first demonstration of LMGFET. In this dissertation, a post-IC LIGA-like process for LMGFET microstructure fabrication has been developed that is compatible with monolithic integration with CMOS circuitry. A two-mask post-IC process …
Pah And Pcb Distribution In Sediment Fractions And Sorptive Phases, Trudy J. Estes
Pah And Pcb Distribution In Sediment Fractions And Sorptive Phases, Trudy J. Estes
LSU Doctoral Dissertations
Contaminant distribution is integral to environmental evaluations of contaminated sediment on every level. The technical and economic feasibility of treatment or beneficial use is a function of the accessibility or separability of the contaminants within the sediment. The magnitude of release to the environment during dredging and disposal is dependent upon the partitioning behavior of the contaminants. Yet, little attention has been paid to contaminant distribution in the fine sediment fractions. Further, conventional distribution coefficients provide little information regarding the relative contaminant loading of each of the sorptive phases. Bioavailability of contaminants in oil and grease, soot and organic carbon, …
Experimental Investigation Of Stick-Slip Behavior In Granular Materials, Lynne E. Roussel
Experimental Investigation Of Stick-Slip Behavior In Granular Materials, Lynne E. Roussel
LSU Master's Theses
The mechanical behavior of granular materials is highly dependent on the arrangement of particles, particle groups, and associated pore spaces. Changes in the internal structure due to large deformation may cause changes in the mechanical behavior. The changes include: particle sliding, rolling, and interaction; shear band formation; and fabric anisotropy. During those changes, stick-slip behavior may take place between the granular particles. The objective of the thesis is to study the factors that influence the stick-slip behavior of granular materials. The influence of particle size, uniformity, confining pressure, density, and strain rate are investigated in this thesis. A series of …
Heuristics For Offset Assignment In Embedded Processors, Satya Swaroop Mahapatra
Heuristics For Offset Assignment In Embedded Processors, Satya Swaroop Mahapatra
LSU Master's Theses
This thesis deals with the optimization of program size and performance in current generation embedded digital signal processors (DSPs) by the design of optimal memory layouts for data. Given the tight constraints on the size, power consumption, cost and performance of these processors, the minimization of code size in terms of the number of instructions required and the associated reduction in execution time are important. Several DSPs provide limited addressing modes and the layout of data, known as offset assignment, plays a critical role in determining the code size and performance. Even the simplest variant of the offset assignment problem …
Effect Of Multiuser Interference On Subscriber Location In Cdma Networks, Rohit Sharma
Effect Of Multiuser Interference On Subscriber Location In Cdma Networks, Rohit Sharma
LSU Master's Theses
The last few years have witnessed an ever growing interest in the field of mobile location systems for cellular systems. The motivation is the series of regulations passed by Federal Communications Commission, requiring that wireless service providers support a mobile telephone callback feature and cell site location mechanism. A further application of the location technology is in the rapidly emerging field of intelligent transportation systems, which are intended to enhance highway safety, location based billing etc. Many of the existing location technologies use GPS and its derivatives which require a specialized subscriber equipment. This is not feasible for popular use, …
Scalable Schemes Against Distributed Denial Of Service Attacks, Kishori Nanduri
Scalable Schemes Against Distributed Denial Of Service Attacks, Kishori Nanduri
LSU Master's Theses
Defense against Distributed Denial of Service (DDoS) attacks is one of the primary concerns on the Internet today. DDoS attacks are difficult to prevent because of the open, interconnected nature of the Internet and its underlying protocols, which can be used in several ways to deny service. Attackers hide their identity by using third parties such as private chat channels on IRC (Internet Relay Chat). They also insert false return IP address, spoofing, in a packet which makes it difficult for the victim to determine the packet's origin. We propose three novel and realistic traceback mechanisms which offer many advantages …