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Articles 1681 - 1710 of 2820

Full-Text Articles in Engineering

Engineering Design Of A Prototype Ammonia Absorption Tower, Andrew Warren Calogero May 2012

Engineering Design Of A Prototype Ammonia Absorption Tower, Andrew Warren Calogero

Honors Capstones

No abstract provided.


Fatigue Performance Of Existing Bridges Under Dynamic Loads From Winds And Vehicles, Wei Zhang Jan 2012

Fatigue Performance Of Existing Bridges Under Dynamic Loads From Winds And Vehicles, Wei Zhang

LSU Doctoral Dissertations

During the life cycle of bridges, varied amplitude of stress ranges on structural details are induced by the random traffic and wind loads. The progressive deteriorated road surface conditions might accelerate the fatigue damage accumulations. Micro-cracks in structural details might be initiated. An effective structural modeling scheme and a reasonable fatigue damage accumulation rule are essential for stress range acquisitions and fatigue life estimation. The present research targets at the development of a fatigue life and reliability prediction methodology for existing steel bridges under real wind and traffic environment with the capability of including multiple random parameters and variables in …


Dynamic Characterization Of Vocal Fold Virbrations, Zhenyi Wei Jan 2012

Dynamic Characterization Of Vocal Fold Virbrations, Zhenyi Wei

LSU Doctoral Dissertations

An emerging trend among voice specialists is the use of quantitative protocols for the diagnosis and treatment of voice disorders. Vocal fold vibrations are directly related to voice quality. This research is devoted to providing an objective means of characterizing these vibrations. Our goal is to develop a dynamic model of vocal fold vibration, and map the parameter space of the model to a class of voice disorders; thus, furthering the assessment and diagnosis of voice disorder in clinical settings.

To this end, this dissertation introduces a new seven-mass biomechanical model for the vibration of vocal folds. The model is …


Biofiltration For Treatment Of Gases Contaminanted By Beta-Caryophyllene, Weili Hu Jan 2012

Biofiltration For Treatment Of Gases Contaminanted By Beta-Caryophyllene, Weili Hu

LSU Master's Theses

Fixed-film biological treatment processes, commonly referred to as biofilters, have been applied to successfully treat a wide variety of volatile organic compounds (VOCs) present in air emitted by a wide variety of industrial operations. The ability of biofilters to treat some classes of VOCs, however, has not been well established. In particular, the performance of biofilters treating sesquiterpenes has not been widely studied. In the research described herein, a laboratory-scale biofilter was operated to treat a synthetic waste gas stream containing â-caryophyllene, a sesquiterpene emitted by conifer trees and industrial wood processing operations. An enrichment culture developed in an initial …


The Biomechanics Of Salt Marsh Vegetation Applied To Wave And Surge Attenuation, James Chatagnier Jan 2012

The Biomechanics Of Salt Marsh Vegetation Applied To Wave And Surge Attenuation, James Chatagnier

LSU Master's Theses

The Northern coast of the Gulf of Mexico is threatened by storm surge and waves from tropical storms. It has been long known that marsh vegetation attenuates storm surge and waves and is vital for sustaining marsh edges. However, little is known about the relationship between plant properties and the amount of storm surge and wave reduction the plants provide. In order to better understand the stiffness properties and physical dimensions of saltmarsh vegetation, which are directly related to their ability to attenuate waves and storm surge, this study has been conducted. Stiffness of salt marsh vegetation was determined through …


Reductive Dechlorination Of High Concentrations Of 1,2-Dichloroethane, 1,2-Dichloropropane, And 1,1,2-Trichloroethane By Dehalogenimonas Sp., Andrew D. Maness Jan 2012

Reductive Dechlorination Of High Concentrations Of 1,2-Dichloroethane, 1,2-Dichloropropane, And 1,1,2-Trichloroethane By Dehalogenimonas Sp., Andrew D. Maness

LSU Master's Theses

The research goals presented here were to evaluate the solvent concentrations over which Dehalogenimonas lykanthroporepellens strain BL-DC-9T and Dehalogenimonas sp. IP3-3 are able to reductively dechlorinate 1,2-dichloroethane (1,2-DCA), 1,2-dichloropropane (1,2-DCP), and 1,1,2-trichloroethane (1,1,2-TCA). Both of these novel bacteria were isolated from contaminated groundwater at the PetroProcessors of Louisiana, Inc. Superfund site located near Baton Rouge. Both cluster in the phylum Chloroflexi, related to, but distinct from, the widely studied, reductively dechlorinating “Dehalococcoides” strains .

Although previous research demonstrated that strains BL-DC-9T and IP3-3 are able to reductively dechlorinate a variety of polyhalogenated alkanes, the solvent concentration at which the strains …


Programmable Cmos Analog-To-Digital Converter Design And Testability, Rajiv Soundararajan Jan 2012

Programmable Cmos Analog-To-Digital Converter Design And Testability, Rajiv Soundararajan

LSU Doctoral Dissertations

In this work, a programmable second order oversampling CMOS delta-sigma analog-to-digital converter (ADC) design in 0.5µm n-well CMOS processes is presented for integration in sensor nodes for wireless sensor networks. The digital cascaded integrator comb (CIC) decimation filter is designed to operate at three different oversampling ratios of 16, 32 and 64 to give three different resolutions of 9, 12 and 14 bits, respectively which impact the power consumption of the sensor nodes. Since the major part of power consumed in the CIC decimator is by the integrators, an alternate design is introduced by inserting coder circuits and reusing the …


Advanced Ceramics And Composites Based On Rice Hulls, Peigen Zhang Jan 2012

Advanced Ceramics And Composites Based On Rice Hulls, Peigen Zhang

LSU Doctoral Dissertations

As a by-product of the agricultural industry, rice hulls are available at large volume across the world. The disposal of the rice hulls itself is a big problem for the rice millers where the rice paddies are peeled off and rice hulls are produced. There have been many disposal methods developed, but the true value of the rice hulls would be more appreciated when they are employed to produce high value-added advanced ceramics. In this dissertation, advanced ceramics, such as AlN nanowires, SiC whiskers, mullite and SiC/Al2O3 nano-sized composites, were developed and studied based on the rice hulls. The SiC …


Synthesis, Characterization, And Testing Of Atomically-Precise Au Clusters Supported On Tio₂ For Co Oxidation, Sarthak Gaur Jan 2012

Synthesis, Characterization, And Testing Of Atomically-Precise Au Clusters Supported On Tio₂ For Co Oxidation, Sarthak Gaur

LSU Doctoral Dissertations

Supported Au catalysts have been studied extensively for CO oxidation. These catalysts are known to catalyze this reaction even at sub-ambient temperatures. While recent literature demonstrates catalytic activity of gold nanoparticles <2 nm, the next stage in fine tuning this catalysis process is to develop gold clusters prepared with atomic precision. Such atomically precise gold catalysts supported on TiO2 hitherto have not been investigated for CO oxidation. The main objective of this work is to synthesize atomically-precise Au38 clusters in a flask-based method using principles of wet chemistry, to characterize these clusters using various advanced spectroscopic techniques, and to test these clusters as potential catalytic materials for CO oxidation. Furthermore, we have tested TiO2-supported Au38 clusters and a commercially purchased Au/TiO2 catalyst for CO oxidation at 30 °C and 60 °C, and used DRIFTS as a probe spectroscopic technique to correlate kinetics with the mechanism occurring on the surface of both catalysts in order to device the mechanistic pathways for CO oxidation. The work reported in this dissertation is the first spectroscopic observation of the phenomena where sulfur may have beneficial effect on the catalytic activity of Au/TiO2 catalysts. Such an interesting observation where sulfur has beneficial effect on catalytic activity of Au/TiO2 catalysts has never been observed in the past. We have also synthesized and tested Fe3O4@Au core-shell nanoparticles supported on TiO2 for CO oxidation. We show for the first time that, core-shell type nanogold catalysts are better suited compared to pure gold nanoparticles for heterogeneous gas phase catalysis of CO oxidation. By conducting comprehensive experiments towards understanding CO oxidation catalysis using X-ray photoelectron spectroscopy, infrared spectroscopy, and temperature programmed reduction, we show that the enhanced catalytic activity is due to a combination of factors ranging from synergistic interaction between Au and Fe, complete removal of organic capping ligands and the presence of metallic gold (Au0) in the active catalyst.


Novel Surface Modifications And New Nanostructured Titania Synthesis For High-Performance Lithium-Ion Batteries And Solar Cells, Dongsheng Guan Jan 2012

Novel Surface Modifications And New Nanostructured Titania Synthesis For High-Performance Lithium-Ion Batteries And Solar Cells, Dongsheng Guan

LSU Doctoral Dissertations

With the rapid development of electronic devices, electrical vehicles and space aerocrafts, rechargeable lithium-ion batteries (LIBs) have attract numerous interests due to high energy and power density, long lifespan and low self discharge. Spinel LiMn2O4 is a promising cathode material for novel LIBs thanks to high working potential, easy synthesis and low cost, but its severe capacity drop mostly due to inevitable reactions with electrolytes is a drawback. In the dissertation, ultrathin and highly-conformal Al2O3 coatings are grown on the surface of micro-sized and nanosized LiMn2O4 with atomic layer deposition. Thickness of Al2O3 ALD coatings can be precisely controlled by …


Structural And Dynamical Properties Of Liquid And Solid Phases Of Ionic Liquids Confined Inside Nanoporous Materials, Ramesh Singh Jan 2012

Structural And Dynamical Properties Of Liquid And Solid Phases Of Ionic Liquids Confined Inside Nanoporous Materials, Ramesh Singh

LSU Doctoral Dissertations

The purpose of this research is to investigate the physical properties of ionic liquids (ILs) confined inside nanopores of different materials and morphologies. We are interested to study the effect of pore material, morphology and addition of organic solvents on the properties of confined ILs. Understanding the behavior of ILs inside nanopores is relevant to potential applications of these systems in electrochemical double layer capacitors (EDLCs) and dye sensitized solar cells (DSSCs). Such a fundamental understanding is also crucial to optimize the synthesis of hard-templated 1D nanostructures (nanorods, nanotubes, nanowires) based on organic salts, which may be imparted properties (e.g., …


Development Of Cost-Effective And Benign Lipid Extraction System For Microalgae, Javed Iqbal Jan 2012

Development Of Cost-Effective And Benign Lipid Extraction System For Microalgae, Javed Iqbal

LSU Doctoral Dissertations

A laboratory-made continuous flow lipid extraction system (CFLES) was devised to extract lipids from microalgae Nannochloropsis sp., a potential feedstock for biodiesel fuel, with a focus to assess the workable temperatures and pressures for possible scale-up applications. Using conventional solvents, the CFLES recovered 100% of the lipids recovered with conventional Soxhlet extraction (USEPA method 3540) at moderate 50 psi pressure and 100°C temperature; conditions significantly lower than those normally used in pressurized liquid extractions requiring specialized equipment. Approximately 87% of the extracted oil was successfully transesterified into biodiesel fuel. For exploring the solvent potential of biodiesel, CFLES was also tested …


A Safety Elements Model For The Building Construction Industry, Cliff Dunlap Dunlap Jan 2012

A Safety Elements Model For The Building Construction Industry, Cliff Dunlap Dunlap

LSU Doctoral Dissertations

The Abstract was sent to Ms. McKenzie as an attachment to an e-mail


Efficacy Of Multifunctionalized Saccharide Constructs For The Attenuation Of Amyloid-Beta Toxicity, Dhruva Dilip Dhavale Jan 2012

Efficacy Of Multifunctionalized Saccharide Constructs For The Attenuation Of Amyloid-Beta Toxicity, Dhruva Dilip Dhavale

LSU Doctoral Dissertations

There is evidence that amyloid-beta (Aβ) toxicity is mediated through interactions and binding with neuronal surface sialic acids in Alzheimer’s disease (AD). The binding affinity is higher if the sialic acids are clustered and toxicity of Aβ was attenuated by removal of neuronal sialic acids. Thus, interfering with cell membrane-Aβ binding using biomimetics that could reproduce the clustered sialic acid structure could present us with a potential target for therapeutic intervention in AD. Based on this hypothesis, we developed several multifunctionalized sialic acid labeled chitosan compounds of different valency, or number of sialic acid per chitosan molecule, to attenuate Aβ …


Controller Reduction For Linear Systems, Lili Kong Jan 2012

Controller Reduction For Linear Systems, Lili Kong

LSU Doctoral Dissertations

This dissertation proposes some H-infinity and H2 performance preserving controller reduction methods for linear systems. The proposed methods can guarantee robust stability and performance for the closed-loop system with the reduced order controllers. Several H-infinity stability and performance preserving controller reduction methods are proposed in this dissertation. It is shown that the weighting functions used in the proposed controller reduction methods can be directly obtained from the parametrization of the H-infinity controllers. Hence, comparing with the most existing controller reduction approaches, the proposed controller reduction methods require less computation and are easy to apply. At the same time, several algorithms …


Quantification Of Nox Reduction Via Nitrate Accumulation On A Tio2 Photocatalytic Concrete Pavement, David James Osborn Jan 2012

Quantification Of Nox Reduction Via Nitrate Accumulation On A Tio2 Photocatalytic Concrete Pavement, David James Osborn

LSU Master's Theses

Field trials of photocatalytic pavements were recently initiated and are presently being considered by many states (e.g., Virginia, Texas, New York, and Missouri). Results from this study originate from the country’s first air-purifying asphalt and concrete photocatalytic pavements, constructed on Dec. 20, 2010. The test area is a pavement site located on the LSU campus. The objective of the study is to validate field photocatalytic degradation of NOx in a field environment by measuring the day to day accumulation of the oxidized byproduct; nitrate salts. The mass of nitrates, produced by the real life photocatalytic pavement, were measured. The measurement …


The Use Of A Mixed Chlorella Cyanobacteria Culture As A Protein Source For Aquaculture, Marjan Sadat Mohtashamian Jan 2012

The Use Of A Mixed Chlorella Cyanobacteria Culture As A Protein Source For Aquaculture, Marjan Sadat Mohtashamian

LSU Master's Theses

The increase in the global demand for fish feed in the last decades has resulted in the over exploitation of natural resources to produce more fishmeal supplies for aquaculture industry. The supply issues and high prices of fishmeal products have raised the incentives to seek for suitable alternatives to replace fishmeal protein. As a by-product of biofuel production process, residual microalgal biomass may be a low cost feed ingredient to the aquaculture diet. The potential of the use of a post lipid extraction Chlorella vulgaris/Leptolyngbya sp. Co-Culture (Louisiana co-culture) as a protein source in aquaculture feeds could help offset fishmeal. …


Stabilization Of Very Weak Subgrade Soil With Cementitious Stabilizers, Sanjay Kumar Dhakal Jan 2012

Stabilization Of Very Weak Subgrade Soil With Cementitious Stabilizers, Sanjay Kumar Dhakal

LSU Master's Theses

To evaluate the effect of high moisture content on the performance of weak subgrade soil and improve the engineering properties of weak subgrade soil through using cementitious materials, five different soils that represent range of subgrade soil in Louisiana (based on plasticity indices) were collected and considered in this research study. All tests on raw soils and treated/stabilized soils were performed on the soil laboratory at the Louisiana Transportation Research Center (LTRC). Ordinary Portland cement and hydrated lime were selected in this study to treat/stabilize the subgrade soils depending upon the soil type and plasticity index. The repeated load triaxial …


Microencapsulation Of Self-Healing Concrete Properties, James Gilford Iii Jan 2012

Microencapsulation Of Self-Healing Concrete Properties, James Gilford Iii

LSU Master's Theses

ABSTRACT Recent studies in the literature have demonstrated the ability of self-healing processes to be effective in enhancing the overall life of concrete. The main goal of this project is to evaluate and to control specific parameters for the production of an effective self-healing matrix that can be utilized within the application of self-healing concrete. Therefore, the project objective is to synthesize microcapsules using dicyclopentadine and sodium silicate and to evaluate the effects of pH, temperature, and agitation rate on microcapsule morphology. The microcapsule diameter, yield analysis, and shell thickness were characterized using scanning electron microscopy. During the experimental analysis, …


Experimental And Numerical Investigation Of Pilot Scale Microwave Assisted Transesterification Process For Biodiesel Production, Pranjali D. Muley Jan 2012

Experimental And Numerical Investigation Of Pilot Scale Microwave Assisted Transesterification Process For Biodiesel Production, Pranjali D. Muley

LSU Master's Theses

The goal of this study was to design and test a pilot scale process for biodiesel production using advanced microwave technology and develop a numerical model for investigating various parameters affecting this process. Dielectric properties of materials play a major role in microwave design of a process. The dielectric properties (dielectric constant ε’ and dielectric loss ε”) of biodiesel precursors: soybean oil, alcohols and catalyst and their different mixtures were measured at four different temperatures (30°C, 45°C, 60°C and 75°C) and in the frequency range of 154 MHz to 4.5 GHz. Results indicate that the microwave dielectric properties of almost …


Micro Grid Stability Improvements By Employing Storage, Sumiti Lamichhane Jan 2012

Micro Grid Stability Improvements By Employing Storage, Sumiti Lamichhane

LSU Master's Theses

Storage devices can be used in a power gird to store the excess energy when the energy production is high and the demand is low and utilize the stored energy when the produced energy cannot meet the high demands of the consumers. This thesis represents a micro grid consisting of a conventional synchronous generator, as well as renewable energy sources, energy storage, and loads in order to investigate the effective energy flow control and transient stability improvement by employing thermal storage. Thermal storage, unlike electrical one (such as battery) is more environmental friendly, has longer life span, and is more …


An Electronic Architecture For Mediating Digital Information In A Hallway Fac̦Ade, Narendra Nallapeta Aswathanarayana Setty Jan 2012

An Electronic Architecture For Mediating Digital Information In A Hallway Fac̦Ade, Narendra Nallapeta Aswathanarayana Setty

LSU Master's Theses

Ubiquitous computing requires integration of physical space with digital information. This presents the challenges of integrating electronics, physical space, software and the interaction tools which can effectively communicate with the audience. Many research groups have embraced different techniques depending on location, context, space, and availability of necessary skills to make the world around us as an interface to the digital world. Encouraged by early successes and fostered by project undertaken by tangible visualization group. We introduce an architecture of Blades and Tiles for the development and realization of interactive wall surfaces. It provides an inexpensive, open-ended platform for constructing large-scale …


Fundamental Characterization Of Asphalt Mixtures: Warm Mix Asphalt Technologies In Flexible Pavement Systems, Bhanu Vijay Vallabhu Jan 2012

Fundamental Characterization Of Asphalt Mixtures: Warm Mix Asphalt Technologies In Flexible Pavement Systems, Bhanu Vijay Vallabhu

LSU Master's Theses

Increasing concerns on environment and greenhouse effect, coupled with increased construction prices led to the development of new technologies by the Asphalt industry to produce Asphalt Concrete (AC) pavements. Extensive research is being done to evaluate the impact and performance of these new technologies. Warm Mix Asphalt (WMA) is one of these technologies that allow mixing, production, placing and compaction of asphalt mixes at significantly lower temperatures as compared to the traditional Hot Mix Asphalt (HMA) practice. Lower temperatures result in reduced fuel usage, fume exhausts, greenhouse gas emissions, wear and tear at plants; while enhancing worker health and safety …


The Impact Of 5s On The Safety Climate Of Manufacturing Workers, Siddarth Srinivasan Jan 2012

The Impact Of 5s On The Safety Climate Of Manufacturing Workers, Siddarth Srinivasan

LSU Master's Theses

The occupational injury rate in the manufacturing sector is higher than the average of all private industries, necessitating safety studies. Occupational safety can be measured through different approaches. Safety climate, a predictive measure of safety, studies the workers’ perceptions of safety of the workplace. This measure includes several dimensions of safety like management commitment, involvement and work place hazard evaluation and was chosen as a method of evaluation in this study. Even though occupational safety is an important concern, management often prioritizes reducing waste and cost. So, there is a necessity for some technique which reduces waste and simultaneously improves …


Design And Optimization Of 2.5 Dimension Porous Media Micromodel For Nanosensor Flow Experiments, Saade Alexis Bou-Mikael Jan 2012

Design And Optimization Of 2.5 Dimension Porous Media Micromodel For Nanosensor Flow Experiments, Saade Alexis Bou-Mikael

LSU Master's Theses

Micromodels are used to visualize and study pore-scale phenomena such as immiscible displacements in porous media, foam flow behavior, and CO2 flooding. The understanding gained from these experiments can be used to develop models to predict future behavior of the reservoir. Most micromodels are constructed using lithography techniques that are restricted to 2D patterns that require artificial generation or manipulation of images to develop connected micromodels. Characteristics innate to the original rock structure are often lost or skewed in developing micromodels that bear little resemblance to the original media. Alternative microfabrication techniques using a micromilling tool have allowed us to …


Hurricane Damage Assessment Process For Residential Buildings, Carol C. Massarra Jan 2012

Hurricane Damage Assessment Process For Residential Buildings, Carol C. Massarra

LSU Master's Theses

Assessing an affected area immediately after a severe natural hazard event and saving the resulting data are vitally important in any effort to reduce future economic losses from natural hazards. These data are used as a record of buildings performance and as a major component for statistical analysis and damage modeling studies. Since these data are used as input for these studies, the data must be assessed and collected in a scientific and standardized way. Despite this requirement, neither a systematic damage assessment process nor a standardized data collection protocol is currently available in the United States to ensure that …


Base-Caged Adenosine Triphosphate As A Model System For Photoactivatable Small Interfering Rna, Amanda Yoesting Hendrix Jan 2012

Base-Caged Adenosine Triphosphate As A Model System For Photoactivatable Small Interfering Rna, Amanda Yoesting Hendrix

LSU Master's Theses

Photocaged adenosine triphosphate (ATP) is one of the earliest examples of exerting spatial-temporal control over the activity of a substrate. The activity of ATP is blocked until near-ultraviolet light exposure photocleaves the cage moiety. Caged ATP has been used for a myriad of applications including kinetic studies of ATP-dependent enzymes. Traditional caging of ATP occurs at the gamma-phosphate, which has been found to competitively inhibit several enzymatic systems. It was hypothesized that blocking access to the adenosine N6 position via cage molecule would prevent the initial enzyme-substrate binding event from occurring prior to photolysis, effectively minimizing competitive inhibition. Utilizing a …


Non-Rigid Registration Of 2-D/3-D Dynamic Data With Feature Alignment, Huanhuan Xu Jan 2012

Non-Rigid Registration Of 2-D/3-D Dynamic Data With Feature Alignment, Huanhuan Xu

LSU Master's Theses

In this work, we are computing the matching between 2D manifolds and 3D manifolds with temporal constraints, that is we are computing the matching among a time sequence of 2D/3D manifolds. It is solved by mapping all the manifolds to a common domain, then build their matching by composing the forward mapping and the inverse mapping. At first, we solve the matching problem between 2D manifolds with temporal constraints by using mesh-based registration method. We propose a surface parameterization method to compute the mapping between the 2D manifold and the common 2D planar domain. We can compute the matching among …


Characterization Of Nanogumbos For Future Electronic Devices, Naveen Narayan Jagadish Jan 2012

Characterization Of Nanogumbos For Future Electronic Devices, Naveen Narayan Jagadish

LSU Master's Theses

In our work on hybrid (organic-inorganic) electronic materials (HEMs), we have developed a reasonably facile method for characterizing GUMBOS or a Group of Uniform Materials Based on Organic Salts. In addition to the versatility of traditional ionic liquids (i.e.-solubility, melting point, viscosity), NanoGUMBOS are functionalizable to exhibit properties such as fluorescence, magnetic susceptibility, and even antimicrobial activity. However, given our interest in the electrical properties of HEMs, we have made first-time measurements of NanoGUMBOS, using conductive probe Atomic Force Microscopy (CP-AFM), in order to deduce their room temperature current-voltage characteristics. In conjunction with the nanoscale imaging of AFM alone, we …


Rapid Microwave Drying Of Non-Food Agricultural Feedstock For Improved Biofuel Production, Laura A. Picou Jan 2012

Rapid Microwave Drying Of Non-Food Agricultural Feedstock For Improved Biofuel Production, Laura A. Picou

LSU Master's Theses

Due to limited supply of traditional fossil based fuels, and increased interest in air and water quality along with other environmental concerns, there has been a rise in the utilization of biomass based energy sources. Many agricultural materials can be used for the production of biofuels, including materials that are typically underutilized such as sweet sorghum bagasse and otherwise nuisance species such as Chinese tallow tree seeds. The goal of this project was to examine the relationship between the dielectric properties of sweet sorghum bagasse and Chinese tallow tree (CTT) seeds, respectively, and frequency and moisture content; to determine pertinent …