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Articles 1201 - 1230 of 2820

Full-Text Articles in Engineering

Osteogenic Potential Of Poly (L-Lactic Acid) Scaffolds Prepared By Thermally Controlled Methods On Human Adipose Derived Stem Cells, Harish Chinnasami Shanmugam Jan 2017

Osteogenic Potential Of Poly (L-Lactic Acid) Scaffolds Prepared By Thermally Controlled Methods On Human Adipose Derived Stem Cells, Harish Chinnasami Shanmugam

LSU Doctoral Dissertations

Thermally Induced Phase Separation (TIPS) method was used to make porous three-dimensional PLLA scaffolds. The effect of imposed thermal profile during freezing of the PLLA in dioxane solution on the scaffold was characterized by their micro-structure, porosity (%), pore-sizes distribution and mechanical strength. The porosity (%) decreased considerably with increasing concentrations of PLLA in the solution, while a decreasing trend was observed with increasing cooling rates. The mechanical strength increases with increase in PLLA concentration and also with increase in the cooling rate for both types of solvents. Therefore, mechanical strength was increased by higher cooling rates while the porosity …


Microcavity Enhanced Beaming And Magneto-Optical Switching Of Light, Ali Haddadpour Jan 2017

Microcavity Enhanced Beaming And Magneto-Optical Switching Of Light, Ali Haddadpour

LSU Doctoral Dissertations

In this dissertation, we show numerically that a compact structure, consisting of multiple optical microcavities at both the entrance and exit sides of a subwavelength plasmonic slit, can lead to greatly enhanced directional transmission through the slit. The microcavities increase the resonant enhancement of the emission in the normal direction and/or the coupling between free space waves and the slit mode. An optimized structure with two microcavities on both the entrance and exit sides of the slit leads to ~ 16 times larger transmission cross section per unit angle in the normal direction compared to the optimized reference slit without …


The Formation Of Polycyclic Aromatic Hydrocarbons From The Pyrolysis Of Model 1-Alkene Fuels, Eva Christine Caspary Jan 2017

The Formation Of Polycyclic Aromatic Hydrocarbons From The Pyrolysis Of Model 1-Alkene Fuels, Eva Christine Caspary

LSU Doctoral Dissertations

To understand the role of 1-alkenes and allylic radicals in the reaction pathways leading to the formation and growth of polycyclic aromatic hydrocarbons (PAH), pyrolysis experiments have been performed with three 1-alkene fuels—propylene (CH₂=CH–CH₃), 1-butene (CH₂=CH–CH₂–CH₃), and 1-pentene (CH₂=CH–CH₂–CH₂–CH₃)—at temperatures of 600 – 1000 °C and a fixed residence time of 0.31 s. The experiments are carried out in an isothermal laminar-flow quartz-tube reactor. Analyses of the pyrolysis products by gas-chromatographic and high-pressure liquid-chromatographic techniques reveal that the three fuels differ in: 1) their conversion behavior, 2) the relative amounts of the major C₂ – C₄ species produced, and 3) …


Modeling Of Size Effects In Metallic Samples Of Confined Volumes, Mohammadreza Yaghoobi Jan 2017

Modeling Of Size Effects In Metallic Samples Of Confined Volumes, Mohammadreza Yaghoobi

LSU Doctoral Dissertations

In material science, size effects is described as the variation of material properties as the sample size changes. In this dissertation, the size dependency of the material strength is addressed as size effects. The size effects underlying mechanisms depend on the nature of the considered material. In the case of crystalline metals, size effects in crystalline metals are governed by the dislocations, as the primary deformation mechanism, and their interactions with one another and other defects such as grain boundaries. In this dissertation, the size and strain rate effects of fcc metallic samples of confined volumes are investigated during the …


Computational Studies On Fluid And Particle Dynamics, Chenguang Zhang Jan 2017

Computational Studies On Fluid And Particle Dynamics, Chenguang Zhang

LSU Doctoral Dissertations

This dissertation is divided into two parts. The first part includes chapter 2 to 4, which focus on development and application of numerical algorithm on particle and fluid simulation. Starting with a pure granular system in a driven cavity setup (Chapter 2), we move on to the immersed boundary simulation of fluid solid interaction (Chapter 3). This part ends with a coupled immersed boundary-discrete particle implementation. The second part includes Chapter 5 and Appendix A, each deals with an independent problem and focuses more on the theoretical aspects. Chapter 5 deals with a classic fluid dynamics problem of thermal wave …


Characterization Of Dehalogenimonas Strains From A Louisiana Superfund Site That Reductively Dehalogenate Polychlorinated Alkanes, Trent Anthony Key Jan 2017

Characterization Of Dehalogenimonas Strains From A Louisiana Superfund Site That Reductively Dehalogenate Polychlorinated Alkanes, Trent Anthony Key

LSU Doctoral Dissertations

The research described in this dissertation was aimed at expanding understanding of the diversity and functional roles of microorganisms able to anaerobically transform chlorinated compounds. During the course of the research, a novel strictly anaerobic bacterial isolate originating from chlorinated solvent contaminated groundwater at a Superfund Site in south Louisiana (USA) was characterized. Phylogenetic analysis based on 16S rRNA gene sequencing placed the newly isolated strain, designated as NSZ-14 T, within the genus Dehalogenimonas but within a separate lineage from previously described species. Like previously described species within the genus Dehalogenimonas (i.e., D. lykanthroporepellens and D. alkenigignens), strain NSZ-14T was …


Tribological And Dynamical Study Of An Automotive Transmission System, Meng Li Jan 2017

Tribological And Dynamical Study Of An Automotive Transmission System, Meng Li

LSU Doctoral Dissertations

The transmission system is critical for automotive and heavy duty equipment due to its prominent role in the powertrain system, which is often challenged with degraded torque capacity and harsh dynamic response. Simulation-guided design can provide appropriate guidelines to resolve these problems with virtual analyses. In current study, the tribological and dynamical study of an automatic transmission is performed at two levels: a wet clutch and powertrain. In this dissertation, tribological study is performed for a wet clutch based on the thermohydrodynamic (THD) analysis that takes the following factors into account. • The groove effect (depth, area, and pattern) is …


Healing Mechanism Investigation Of Self-Healing Concrete By Microencapsulated Calcium Nitrate, Gabriel Andres Arce Amador Jan 2017

Healing Mechanism Investigation Of Self-Healing Concrete By Microencapsulated Calcium Nitrate, Gabriel Andres Arce Amador

LSU Doctoral Dissertations

Durability of reinforced concrete structures depends highly on the integrity of the concrete which protects the structure from the environment. However, concrete is a brittle material and as such it is prone to cracking which allows for detrimental agents to penetrate the structure and produce early deterioration. Embedding microcapsules with chemical healing agents in concrete materials for self-healing applications as well as implementing SMAs as reinforcement of concrete structures for self-closing of cracks are both state-of-the-art techniques with enormous potential for enhancement of concrete infrastructure durability. In this work, both techniques are combined as an alternative for superior self-healing of …


Development And Test Of A Sweet Sorghum Feedstock Separation Technology And The Effect Of Trash On Fermentable Sugar Yield In Juice And Syrup, Edgar Jose Tobias Corado Jan 2017

Development And Test Of A Sweet Sorghum Feedstock Separation Technology And The Effect Of Trash On Fermentable Sugar Yield In Juice And Syrup, Edgar Jose Tobias Corado

LSU Master's Theses

In the recent years, processing sweet sorghum feedstock to obtain syrup for biofuels production is an option that has gained attention, especially where sugar cane milling infrastructure is already available; however, the leafy matter and panicles (trash) in the feedstock could negatively impact the process. Therefore, it seems sensible to reduce the trash level in the feedstock prior to milling and expand the current knowledge on the effect of trash in the juice and syrup. In this project, a pneumatic system to separate the leaves from sweet sorghum harvested with a sugar cane billet harvester was tested and a panicles …


Experimental Study Of Frequency Oscillations In Islanded Power System, Kevin Daniel Wellman Jan 2017

Experimental Study Of Frequency Oscillations In Islanded Power System, Kevin Daniel Wellman

LSU Master's Theses

Since the introduction of power electronics to the grid, the power system has quickly changed. Fault detection and removal is performed more accurately and at quicker response time, and non-inertia driven loads have been added. This means stability must continue to be a main topic of concern to maintain a stable synchronized grid. In this thesis a lab was designed, constructed, and tested for the purpose of studying transient stability in power systems. Many different options were considered and researched, but the focus of this paper is to describe the options chosen. The lab must be safe to operate and …


Development Of Laboratory Scale Conical Spouted Bed Reactors, James Blake Gegenheimer Jan 2017

Development Of Laboratory Scale Conical Spouted Bed Reactors, James Blake Gegenheimer

LSU Master's Theses

Conical spouted beds (CSBs) are a form of a fluidized bed that is characteristic of its spouting behaviors. The conical spouted bed has a small inlet that diverges through a conical section towards a larger fixed-diameter column which is filled with static spouting media. By injecting a fluid at a sufficient velocity, a small spout will form in which the spouting media will become entrained by the fluid particles and carried to the top of the system where it will circulate back into the system. It has been shown that CSB reactors have the potential for increasing the heat circulation …


Estimation Of Rfid Tag Population Size By Gaussian Estimator, Md Mahmudul Hasan Jan 2017

Estimation Of Rfid Tag Population Size By Gaussian Estimator, Md Mahmudul Hasan

LSU Master's Theses

Radio Frequency IDenti cation (RFID) systems are prevalent in all sorts of daily life endeavors. In this thesis we propose a new method to estimate RFID tag population size. We have named our algorithm "Gaussian Estimation of RFID Tags,"namely, GERT. We present GERT under both {0,1} and {0,1,e} channel models, and in both cases the estimator we use is a well justi ed Gaussian random variable for large enough frame size based on Central Limit Theorem for triangular arrays. The most prominent feature of GERT is the quality with which it estimates a tag population size. We support all the …


Integration Of Shape-Memory Alloys And Self-Healing Microcapsules To Enhance Concrete Durability, Luis Adolfo Bonilla Jan 2017

Integration Of Shape-Memory Alloys And Self-Healing Microcapsules To Enhance Concrete Durability, Luis Adolfo Bonilla

LSU Doctoral Dissertations

Self-healing is a term that has not been used for building material until a few decades ago. The concept of developing a material that mimics what living organisms do, such as identify and repair damage, rather than interesting, constitutes a necessity in today’s deteriorated infrastructure. Concrete is one of the main building blocks that support our society’s roads, buildings, and dams. Increasing the service life of such structures will have an important socio-economic benefit in our society. Self-healing methods in concrete have been studied in order to minimize human intervention in maintenance procedures. Previous research in this area has provided …


Channel Estimation And Symbol Detection In Massive Mimo Systems Using Expectation Propagation, Kamran Ghavami Jan 2017

Channel Estimation And Symbol Detection In Massive Mimo Systems Using Expectation Propagation, Kamran Ghavami

LSU Doctoral Dissertations

The advantages envisioned from using large antenna arrays have made massive multiple- input multiple-output systems (also known as massive MIMO) a promising technology for future wireless standards. Despite the advantages that massive MIMO systems provide, increasing the number of antennas introduces new technical challenges that need to be resolved. In particular, symbol detection is one of the key challenges in massive MIMO. Obtaining accurate channel state information (CSI) for the extremely large number of chan- nels involved is a difficult task and consumes significant resources. Therefore for Massive MIMO systems coherent detectors must be able to cope with highly imperfect …


Distributed Kalman Filters Over Wireless Sensor Networks: Data Fusion, Consensus, And Time-Varying Topologies, Jianming Zhou Jan 2017

Distributed Kalman Filters Over Wireless Sensor Networks: Data Fusion, Consensus, And Time-Varying Topologies, Jianming Zhou

LSU Doctoral Dissertations

Kalman filtering is a widely used recursive algorithm for optimal state estimation of linear stochastic dynamic systems. The recent advances of wireless sensor networks (WSNs) provide the technology to monitor and control physical processes with a high degree of temporal and spatial granularity. Several important problems concerning Kalman filtering over WSNs are addressed in this dissertation. First we study data fusion Kalman filtering for discrete-time linear time-invariant (LTI) systems over WSNs, assuming the existence of a data fusion center that receives observations from distributed sensor nodes and estimates the state of the target system in the presence of data packet …


A New Computational Framework For Efficient Parallelization And Optimization Of Large Scale Graph Matching, Sahar Marefat Navaz Jan 2017

A New Computational Framework For Efficient Parallelization And Optimization Of Large Scale Graph Matching, Sahar Marefat Navaz

LSU Doctoral Dissertations

There are so many applications in data fusion, comparison, and recognition that require a robust and efficient algorithm to match features of multiple images. To improve accuracy and get a more stable result is important to take into consideration both local appearance and the pairwise relationship of features. Graphs are a powerful and flexible data structure, allowing for the description of complex relationships between data elements, whose nodes correspond to salient features and edges correspond to relational aspects between features. Therefore, the problem of graph matching is to find a mapping between the two sets of nodes that preserves the …


Analytical Solutions And Multiscale Creep Analysis Of Functionally Graded Cylindrical Pressure Vessels, Jasem Amjad Ahmed Jan 2017

Analytical Solutions And Multiscale Creep Analysis Of Functionally Graded Cylindrical Pressure Vessels, Jasem Amjad Ahmed

LSU Doctoral Dissertations

This study deals with the time-dependent creep analysis of functionally graded thick-cylinders under various thermal and mechanical boundary conditions. Firstly, exact thermoelastic stress, and iterative creep solutions for a heat generating and rotating cylindrical vessel made of functionally graded thermal and mechanical properties are proposed. Equations of equilibrium, compatibility, stress-strain, and strain-displacement relations are solved to obtain closed-form initial stress and strain solutions. It is found that material gradient indices have significant influences on thermoelastic stress profiles. For creep analysis, Norton’s model is incorporated into rate forms of the above-mentioned equations to obtain time-dependent stress and strain results using an …


Performance Evaluation Of Virtual Flow Metering Models And Its Application To Metering Backup And Production Allocation, Kahila Mokhtari Jadid Jan 2017

Performance Evaluation Of Virtual Flow Metering Models And Its Application To Metering Backup And Production Allocation, Kahila Mokhtari Jadid

LSU Doctoral Dissertations

In the oil and gas industry, reliable and accurate measurements of the amount of oil, gas and water being produced by individual wells is essential. The production revenue for each well is determined from measured flow rates. Measurement of well production can be achieved by using multiphase flow meters on individual wells. However, the use of such metering technique is not always reliable or economical. As an alternative technique to monitoring individual well performance in real-time, multiphase flow simulators together with pressure and temperature sensors located at different locations in the production systems have been recently deployed to estimate individual …


A Model-Centric Framework For Advanced Operation Of Crystallization Processes, Navid Ghadipasha Jan 2017

A Model-Centric Framework For Advanced Operation Of Crystallization Processes, Navid Ghadipasha

LSU Doctoral Dissertations

Crystallization is the main physical separation process in many chemical industries. It is an old unit operation which can separate solids of high purity from liquids, and is widely applied in the production of food, pharmaceuticals, and fine chemicals. While industries in crystallization operation quite rely on rule-of-thumb techniques to fulfill their requirement, the move towards a scientific- and technological- based approach is becoming more important as it provides a mechanism for driving crystallization processes optimally and in more depth without increasing costs. Optimal operation of industrial crystallizers is a prerequisite these days for achieving the stringent requirements of the …


An Application Programming Interface For Parliamentary Procedure, Grant David Bourque Nov 2016

An Application Programming Interface For Parliamentary Procedure, Grant David Bourque

Honors Capstones

No abstract provided.


Pentaerythritol Triacrylate-Co-Trimethylolpropane Nanocomposite Scaffolds As Osteogenic Components For Bone Tissue Engineering, Mollie Marie Smoak May 2016

Pentaerythritol Triacrylate-Co-Trimethylolpropane Nanocomposite Scaffolds As Osteogenic Components For Bone Tissue Engineering, Mollie Marie Smoak

Honors Capstones

No abstract provided.


Material Evaluation Of A Lightweight, Automated Canned Pet Food Dispenser, Kathryn Marie Carr May 2016

Material Evaluation Of A Lightweight, Automated Canned Pet Food Dispenser, Kathryn Marie Carr

Honors Capstones

No abstract provided.


The Exacerbating Effect Of Coastal Erosion To Orphan Well Risk Analysis In Terrebonne Parish, Taylor Reeves Apr 2016

The Exacerbating Effect Of Coastal Erosion To Orphan Well Risk Analysis In Terrebonne Parish, Taylor Reeves

Honors Capstones

No abstract provided.


Modeling Of Reaction Kinetics And Mass Transfer Of Carbon Dioxide Electrochemical Reduction, Sneha Seetharama Apr 2016

Modeling Of Reaction Kinetics And Mass Transfer Of Carbon Dioxide Electrochemical Reduction, Sneha Seetharama

Honors Capstones

No abstract provided.


Zein Nanoparticle Interaction With Soybean Plants, Kurt Ristroph Apr 2016

Zein Nanoparticle Interaction With Soybean Plants, Kurt Ristroph

Honors Capstones

No abstract provided.


Impact Of Additive Manufacturing Technologies And The Development Ofa Mixed Metal Powderbed Additive Manufacturing System, Gerald L. Knapp Apr 2016

Impact Of Additive Manufacturing Technologies And The Development Ofa Mixed Metal Powderbed Additive Manufacturing System, Gerald L. Knapp

Honors Capstones

No abstract provided.


Single Cell Encapsulation Using A Microfluidic Droplet Generator, Seleipiri Charles Apr 2016

Single Cell Encapsulation Using A Microfluidic Droplet Generator, Seleipiri Charles

Honors Capstones

No abstract provided.


Core-Shell Nanoparticles For The Desulfurization Of Biogas, Joshua Saltz Apr 2016

Core-Shell Nanoparticles For The Desulfurization Of Biogas, Joshua Saltz

Honors Capstones

No abstract provided.


Modeling The Effects Of Mass Transport On The Electrochemical Reduction Of Co2 At Cu2o Surfaces, Edward Alexander Thistlethwaite Iii Apr 2016

Modeling The Effects Of Mass Transport On The Electrochemical Reduction Of Co2 At Cu2o Surfaces, Edward Alexander Thistlethwaite Iii

Honors Capstones

No abstract provided.


Cobalt-Based Catalysts For The Conversion Of Biomass-Derived Syngas To Ethanol And Higher Oxygenates, Zi Wang Jan 2016

Cobalt-Based Catalysts For The Conversion Of Biomass-Derived Syngas To Ethanol And Higher Oxygenates, Zi Wang

LSU Doctoral Dissertations

Higher oxygenates synthesis by catalytic conversion of synthesis gas are the potential approaches to replace fossil fuels and produce chemicals for pharmaceutical manufacture, detergents and polymer industry. Cobalt-based catalysts are the most promising catalysts to replace noble metal catalysts for producing ethanol, acetaldehyde and higher oxygenates via CO hydrogenation. The formation of higher oxygenates requires active sites that can adsorb CO non-dissociatively and insert to the alkyl intermediate. The hydrogenation of the CO-inserted intermediates yields C2 and C2+ oxygenates. The main focus of this study is to investigate the active site for non-dissociative CO adsorption, and the modification of the …