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Full-Text Articles in Engineering

Damage Mechanics Of Composite Materials Using Fabric Tensors, Ziad N. Taqieddin Jan 2005

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 Jan 2005

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 …


Transform Techniques And Non-Stationarity With An Emphasis On Network Applications, Phat Piron Jan 2005

Transform Techniques And Non-Stationarity With An Emphasis On Network Applications, Phat Piron

LSU Master's Theses

The recent years brought a phenomenal development of Internet. It is, therefore, important to find some ways to improve the performances. The first step in this direction is the characterization and modeling of the network traffic. It has been tested that the network traffic behaves like a self-similar process, while packets interarrivals time possess the long-range dependence property. In particular, we model them by using fractional Brownian motion and fractional Gaussian noise, respectively. Note that, the former is just the cumulative sum of the latter. By using these concepts, the traffic characterization reduces to the estimation of one value: the …


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 …


An Evaluation Of Ansys Contact Elements, Serhan Sezer Jan 2005

An Evaluation Of Ansys Contact Elements, Serhan Sezer

LSU Master's Theses

The ANSYS code offers stress analysts a variety of contact element options: point-to-surface or surface-to-surface and low-order or high-order elements, in concert with any one of five contact algorithms (augmented Lagrangian, penalty method, etc.). This raises questions as to what option performs best under what circumstances. Here we offer some answers to these questions by examining performance in some numerical experiments. The numerical experiments focus on frictionless contact with a rigid indenter; even so, the number of experiments involved is quite large. The experiments use a battery of test problems with known analytical solutions: contact patch tests with nodes matching …


Deposition Of Carbon Layers From Cyclohexane By Thermal Chemical Vapor Deposition, Bharath Thiruvengadachari Jan 2005

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 …


Experimental Investigation Of Stick-Slip Behavior In Granular Materials, Lynne E. Roussel Jan 2005

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 …


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 …


Cognitive Memory Effects On Non-Linear Video-Based Learning, Katherine Renee Comeaux Jan 2005

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 …


An Application Of Parallel Computation To Collaborative Optimization, Shahab Nayyer Jan 2005

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 Jan 2005

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 …


Heuristics For Offset Assignment In Embedded Processors, Satya Swaroop Mahapatra Jan 2005

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 …


Modeling The Fate And Transport Of Chlorinated Benzenes In Baton Rouge Bayou, Sudheer Nimmagadda Jan 2005

Modeling The Fate And Transport Of Chlorinated Benzenes In Baton Rouge Bayou, Sudheer Nimmagadda

LSU Master's Theses

Knowledge of the fate and transport of chlorinated benzenes is necessary at certain sites for effective remediation of contaminated soils using plants. Current research is examining the capability of wetland plants to catalyze degradation or attenuate migration, but again requires knowledge of the uptake of contaminants from an aqueous environment. A two stage model was used to estimate the rate of uptake of contaminants from sediments. The first stage of the model predicts pollutant leaching rates from sediments to the overlying water, which would then be fed into the plant or bioreactor model systems. In this study the flux from …


Traffic Engineering And Path Protection In Mpls Virtual Private Networks, Pooja S. Aniker Jan 2005

Traffic Engineering And Path Protection In Mpls Virtual Private Networks, Pooja S. Aniker

LSU Master's Theses

Traffic Engineering (TE) attempts to establish paths for the flow of data in a network so as to optimize the resource utilization and maximize the network performance. One of the main goals of Traffic Engineering is to bring about efficient and reliable network operations. Constraint based routing is the key to Multiprotocol label switching TE. Constraint based routing helps to manage traffic paths within a MPLS network and allows for traffic to flow along certain desired paths. MPLS also supports explicit routing thus providing TE capabilities. MPLS TE enables resiliency and reliability to be built into networks, thus increasing the …


Evaluation Of The Spatial Removal Of Nitrogen In The Marshland Upwelling System, Andrea Reneé Turriciano Jan 2005

Evaluation Of The Spatial Removal Of Nitrogen In The Marshland Upwelling System, Andrea Reneé Turriciano

LSU Master's Theses

The Marshland Upwelling System (MUS) is an alternative onsite wastewater treatment technology designed to utilize the natural ecology of saltwater marshes to remove human-borne contaminants. Over the past twelve years, MUSs have been installed in Port Fourchon, Louisiana, Moss Point, Mississippi, and Bayou Segnette, Louisiana. The purpose of this study was to investigate the nitrogen reduction capabilities of the Bayou Segnette system. The objectives of this research were to: 1) determine the first-order removal constants necessary for the development of nitrogen transport equations, 2) explore the spatial dependencies of nitrogen concentrations within the Bayou Segnette system, and 3) determine the …


Simulation Of A Micro Jet Cooling Array, Pierre Montanier Jan 2005

Simulation Of A Micro Jet Cooling Array, Pierre Montanier

LSU Master's Theses

The new generation of electronic devices are more powerful, and they produce more heat. Hence, there is a need for micro cooling systems for removing the heat from these micro chips. This research focused on one micro cooling system-the micro jet cooling array. Some test simulations were made on a single jet cooling system. In addition, the inlet Reynolds number was varied in order to obtain the variation of the heat transfer coefficient. These simulations gave a basic idea of how the impingement cooling method works on the micro jet cooling array. Numerical simulations were made on the actual micro …


Behavior Of Heat Straightened Plates Bent Along The Minor Axis, Manish Sharma Jan 2005

Behavior Of Heat Straightened Plates Bent Along The Minor Axis, Manish Sharma

LSU Master's Theses

The heat straightening method of repair for damaged steel structures has been employed for many years. The method was based on the experience of practitioners. Recent research has given an engineering background for the technique and established certain procedures and guidelines to be followed while using heat straightening. Although a scientific basis has now been established, there still exist some major gaps in the data. Misuse of the heat straightening technique has produced fractures in the steel during repair.There are two parameters that may be keys to limiting fracture sensitivity: degree of damage and application of jacking force stress during …


Remote Power Delivery For Hybrid Integrated Bio-Implantable Electrical Stimulation System, Venkat Reddy Gaddam Jan 2005

Remote Power Delivery For Hybrid Integrated Bio-Implantable Electrical Stimulation System, Venkat Reddy Gaddam

LSU Master's Theses

Bio-implantable devices such as heart pacers, gastric pacers and drug-delivery systems require power for carrying out their intended functions. These devices are usually powered through a battery implanted with the system or are wired to an external power source. In this work, a remote power delivery system (RPDS) is considered as a means to charge rechargeable batteries that power a Bio-implanted Electrical Stimulation System (BESS). A loosely coupled inductive power transmitter and receiver system has been designed to recharge batteries for a bio-implanted gastric pacer. The transmitter coil is periodically worn around the waist. The receiver coil, rechargeable batteries, battery-charging …


Mathematical Models For Estimating Volatile Chemical Emissions From Dredging Operations, Kenneth Alexander Fountain Jan 2005

Mathematical Models For Estimating Volatile Chemical Emissions From Dredging Operations, Kenneth Alexander Fountain

LSU Master's Theses

Dredging operations have been a common remediation for contaminated sediment in an effort to reduce the harmful impact on the environment. The objective of this research was to create models used for estimating chemical release to air from remediating the Indiana Harbor and Canal (IHC) as three separate dredging operations; the Dredge Site, Exposed DM CDF, and Ponded CDF. The evaporative flux estimations are based on a two-resistance mass transport path inclusive of both the molecular diffusion in porous media and interfacial airside mass transport resistances. Several chemodynamic algorithms were used in calculating key transport parameters. Laboratory tests were performed …


Blind Multiridge Detection And Reconstruction Using Ultrasonic Signals, Rekha Katragadda Jan 2005

Blind Multiridge Detection And Reconstruction Using Ultrasonic Signals, Rekha Katragadda

LSU Master's Theses

Time-frequency signal analysis has been widely applied in the modern radar, acoustic, sonar and ultrasonic signal processing techniques. Recently, the nondestructive testing (NDT) techniques via the ultrasonic instrumentation have shown the striking capability of the quality control for the material fabrication industry. In this thesis, we first provide a general mathematical model for the ultrasonic signals collected by pulse-echo sensors and then design a totally blind, novel, signal processing NDT technique relying on neither a priori signal information nor any manual effort. The signature signal can be blindly extracted by using the automatic optimal frame size selection for further modeling …


Sediment Tmdl Calculations For Amite River, Pradeep Kumar Mishra Jan 2005

Sediment Tmdl Calculations For Amite River, Pradeep Kumar Mishra

LSU Master's Theses

The Amite River is recognized as one of the 15 water bodies impaired by sediments in Louisiana. A sediment TMDL calculation for the Amite River is required by the EPA. Based on EPA’s Protocol sediment TMDL calculations for the Upper Amite River are conducted in this thesis. The sediment TMDL calculations are composed of four parts: (1) Development of a new sediment transport and dispersion model for the Amite River, (2) Estimation of sediment loads (sources) produced by watershed erosion, (3) Flow computation, and (4) Determination of sediment TMDL for the Amite River. Using the mass conservation principle and Reynolds …


Flame Synthesis Of Carbon-Nanostructures, Saritha Perla Jan 2005

Flame Synthesis Of Carbon-Nanostructures, Saritha Perla

LSU Master's Theses

Ever since their discovery carbon nanostructures (nanotubes and nanofibers) have attracted a lot of interest, due to their striking physical, chemical, mechanical and electrical properties, and paves the path to a wide range of applications. Large quantities of these structures are necessary to make their applications viable. The challenge is to produce them in bulk and in an economical way. Current methods like Arc discharge have the disadvantages of short tube lengths, CVD generated nanomaterials are often riddled with defects and although laser ablation method produces pure and high yield of nanotubes, is a costly technique with expensive lasers and …


Electrodeposition Of Auco Alloys And Multilayers, Maoshi Guan Jan 2005

Electrodeposition Of Auco Alloys And Multilayers, Maoshi Guan

LSU Master's Theses

Electrodeposited AuCo and Au/Co multilayers are of interest as potential materials for MEMS components. AuCo alloys have been fabricated by the electrodeposition technique, but from cyanide-containing electrolyte. In this study, we explored the electrodeposition of AuCo and Au/Co multilayer thin films, and nanowires, from a non-cyanide electrolyte. Two variables were considered: the concentration of citric acid and pH. The changes in composition were described by the differences in the partial current densities. The effect of pH and citric acid concentration on the deposit composition and current efficiency was investigated. Results showed that a lower citric acid concentration was favored for …


Development Of Process Techniques For Bistable Microbeam Fabrication, Varsha Francis Jan 2005

Development Of Process Techniques For Bistable Microbeam Fabrication, Varsha Francis

LSU Master's Theses

A design which uses bistable beams to modulate light is suggested in this thesis and appropriate processing techniques are presented. A beam when placed under compression above the Euler limit has two stable states. The compression in an electroplated beam can be controlled by the plating current density of nickel during electrodeposition. This beam is attached to an electromechanical comb. Voltages applied to the combs cause the beam to snap from one stable state to another. Structures were designed with dimensions that gave feasible voltages, snap distances, compressions required to snap. A two mask process was used for the fabrication …


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 …


Modeling Destination Choice In Hurricane Evacuation With An Intervening Opportunity Model, Bin Chen Jan 2005

Modeling Destination Choice In Hurricane Evacuation With An Intervening Opportunity Model, Bin Chen

LSU Master's Theses

In this study, a trip distribution model for hurricane evacuation using the intervening opportunity method was developed. Post Hurricane Floyd survey data was used for model calibration and comparison. To model the behavior that people tend to evacuate away from the path of the hurricane, a new concept of equal destination attractiveness was introduced and an extended intervening opportunity model was built on this basis and implemented in TransCAD. The gravity model, intervening opportunity model and its extended version were compared using several statistical measures. This study demonstrates that it is possible to use the intervening opportunity theory to model …


Synthesis Of Poly(Dl-Lactide-Co-Glycolide) Nanoparticles With Entrapped Magnetite, Carlos Ernesto Astete R. Jan 2005

Synthesis Of Poly(Dl-Lactide-Co-Glycolide) Nanoparticles With Entrapped Magnetite, Carlos Ernesto Astete R.

LSU Master's Theses

The goal of the research was to synthesize magnetic polymeric nanoparticles (MPNPs) under 100 nm in diameter, for future drug delivery applications. The thesis is divided into two main sections. In the first section, a quantitative, and comprehensive description of the top-down synthesis techniques available for poly(lactide-co-glycolide) (PLGA) and magnetic polymeric nanoparticles (MPNPs) formation is provided, as well as the techniques commonly used for nanoparticle characterization. In the second part, a novel way to form MPNPs is presented. The emulsion evaporation method was selected as the method of choice to form poly(lactide-co-glycolide) (PLGA) nanoparticles with entrapped magnetite (Fe3O …


Advanced Grid Stiffened Composite Structures, Dinesh Maricherla Jan 2005

Advanced Grid Stiffened Composite Structures, Dinesh Maricherla

LSU Master's Theses

In this study Advanced Grid Stiffened (AGS) composite structures are developed and analyzed for their mechanical properties. It is widely known that these structures possess light weight, high strength, and inherent impact resistance. Because of the advantages mentioned above, the AGS composite structures find many applications in aerospace, ship building and construction industries. The purpose of this study is to manufacture AGS composite structures and analyze AGS composite structures as reinforcement members. A FEA model is also developed and validated with the test results. Parametric analysis is also conducted to investigate the effects of different design parameters on these structures. …


Factors Effecting Field Emission From Multiwalled Carbon Nanotubes, Abhilash Krishna Jan 2005

Factors Effecting Field Emission From Multiwalled Carbon Nanotubes, Abhilash Krishna

LSU Master's Theses

Carbon nanotubes (CNT) have emerged to be one of the most versatile of materials ever discovered. The small dimensions, high electrical conductivity and strength along with other physical and electrical properties make them a unique material with a wide range of promising applications. One such use is that of CNTs as electron beam sources. A typical CNT has a diameter of only a few nanometers but can be hundreds of microns long. Applying a voltage across the length of such an object results in field emission of electrons from one end of the tube. This effect is due to intense …


High-Freequency Cmos Vlsi Chip Testability And On-Chip Interconnect Modeling, Evan Ross Shultz Jan 2005

High-Freequency Cmos Vlsi Chip Testability And On-Chip Interconnect Modeling, Evan Ross Shultz

LSU Master's Theses

As high-speed digital and radio-frequency mixed-signal integrated circuits become increasingly common in product designs in industry, it is important for VLSI designers to be familiar with the challenges of chip testing and the behavior of circuit elements, including on-chip interconnect, at high frequencies. Expensive, specialized test equipment and software simulation packages for high-frequency chip testing and design are not always accessible for student research. This thesis documents the setup and characterization of a best-possible environment for high-frequency chip testing and data acquisition using existing laboratory equipment and resources. Experimental methodologies and measurement results of on-chip interconnect signal integrity and delay, …