Engineering Commons^™

Quantitative Non-Destructive Evaluation Of Rebar Diameter And Corrosion Damage In Concrete Using Ground Penetrating Radar, Md Istiaque Hasan

Civil Engineering Dissertations - Archive

The purpose of this study is to develop new methods for quantitative estimation of rebar diameter and loss of area of rebar due to corrosion using Ground Penetrating Radar (GPR). The existing methods of determining the rebar diameter using GPR are not accurate and the existing methods for evaluating corrosion using GPR are qualitative. The study included in this dissertation uses a 2.6 GHz antenna to estimate the diameter of rebar using two different approaches. The approaches use digital image processing of GPR ragargrams and maximum normalized reflection amplitude form the rebar to estimate the diameter. A novel method to …

Discrete Element Modeling Of Geogrid Reinforced Granular Media, Asheesh Pradhan

Civil Engineering Dissertations - Archive

Geogrids have proven to be economical solution in improving ground conditions for construction in foundations, retaining walls, railway tracks, and pavements. Hence researchers have started studying the geogrid reinforcement in detail to understand the working of geogrid and parameters affecting it. Following the advent of faster computers and efficient algorithms researcher have started using discrete element method (DEM) to study geogrid reinforcement since DEM provides particulate level of interaction and understanding and is the closest resemblance of the physical phenomenon. However, the research works are widely spread lacking comprehensive review of factors that can affect such models. This research studies …

The Space Infrastructure Vulnerability Cadastre: Orbital Debris Critical Loads, Adrian V. Gheorghe, Daniel E. Yuchnovicz

Engineering Management & Systems Engineering Faculty Publications

Orbital debris from over 50 years of human activity in space are threatening the operations of existing and future satellites and the sustainability of high-value satellite orbits. This technical memorandum calls for the development of a cadastre that depicts the vulnerability of critical satellite orbits to accumulating orbital debris. A space infrastructure vulnerability cadastre could serve as a governance tool for use by developers and operators of critical space infrastructures to better communicate the current and future vulnerability of high-value orbits to the accumulation of orbital debris. These high-value orbits are susceptible to "loss" for decades or centuries if generation …

Optimal Uses Of Biomass Resources In Distributed Applications, Joshua J. Jackson

Theses and Dissertations--Biosystems and Agricultural Engineering

Biomass production is spatially distributed resulting in high transportation costs when moving dedicated biomass crops and crop residues. A multifaceted approach was taken to address this issue as the low bulk and energy density of biomass limits transportation efficiency. Two systems were analyzed for the conversion of biomass into a denser feedstock applicable to on-farm use. Pelletization was able to densify the material into a solid fuel. Using a pilot scale flat ring pellet mill, the density of the material was able to be increased to at least 4.4 times that of uncompressed material. Pellet durability was found to be …

Characterization Of Two Biochars Derived From Horse Muck And Their Ability To Reduce Pathogen Transport In Soil, David Griffith

Theses and Dissertations--Biosystems and Agricultural Engineering

Biochars have been created and characterized from a variety livestock manure biomass including poultry, dairy, and swine. However, no research has been conducted on the physical and chemical makeup of biochar pyrolyzed from horse muck. Two horse muck derived biochars containing either straw (HS) or woodchip (HW) bedding were pyrolyzed at 700°C and characterized for their physical and chemical properties. Tests revealed both biochars had high alkalinity, moderate specific conductivity, and low surface area as compared to other biochars in the literature. HS contained more mineral structures than HW. Scanning electron microscopy presented differences in particle shape, size, and presence …

Demonstrating "Data Near Here": Scientific Data Search, Veronika Margaret Megler, David Maier

Computer Science Faculty Publications and Presentations

Prior work proposed "Data Near Here" (DNH), a data search engine for scientific archives that is modeled on Internet search engines. DNH performs a periodic, asynchronous scan of each dataset in an archive, extracting lightweight features that are combined to form a dataset summary. During a search, DNH assesses the similarity of the search terms to the summary features and returns to the user, at interactive timescales, a ranked list of datasets for further exploration and analysis. We will demonstrate the search capabilities and ancillary metadata-browsing features for an archive of observational oceanographic data. While comparing search terms to complete …

Misfit: Mining Software Fault Information And Types, Billy R. Kidwell

Theses and Dissertations--Computer Science

As software becomes more important to society, the number, age, and complexity of systems grow. Software organizations require continuous process improvement to maintain the reliability, security, and quality of these software systems. Software organizations can utilize data from manual fault classification to meet their process improvement needs, but organizations lack the expertise or resources to implement them correctly.

This dissertation addresses the need for the automation of software fault classification. Validation results show that automated fault classification, as implemented in the MiSFIT tool, can group faults of similar nature. The resulting classifications result in good agreement for common software faults …

Multilevel Ant Colony Optimization To Solve Constrained Forest Transportation Planning Problems, Pengpeng Lin

Theses and Dissertations--Computer Science

In this dissertation, we focus on solving forest transportation planning related problems, including constraints that consider negative environmental impacts and multi-objective optimizations that provide forest managers and road planers alternatives for making informed decisions. Along this line of study, several multilevel techniques and mataheuristic algorithms have been developed and investigated. The forest transportation planning problem is a fixed-charge problem and known to be NP-hard. The general idea of utilizing multilevel approach is to solve the original problem of which the computational cost maybe prohibitive by using a set of increasingly smaller problems of which the computational cost is cheaper.

The …

Assessment Of The Wear Effects Of Alumina-Nanofluids On Heat-Exchanger Materials, Fnu Aktaruzzaman

College of Graduate Studies: Theses & Dissertations

Nanofluids are nano-size-powder suspensions in liquids that are mainly studied for their abnormal thermal transport properties, and hence as enhanced alternatives to ordinary cooling fluids. The tribological effects of nanofluids are, however, largely unknown, in particular their likely wear and/or erosion effects, because of their interaction with cooling-system (heat-exchanger) materials. The thesis presents research to establish methodologies for testing and evaluating surface-change by nanofluid impact. The work is presented on development of novel test rigs and testing methodologies, and on the use of typical surface analysis tools for assessment of wear and erosion that may be produced by nanofluids; prediction …

Heating Based Model Analysis For Explosive Emission Intitiation At Metal Cathodes, A. Majzoobi, R. P. Joshi, A. Neuber, J. Dickens

Electrical & Computer Engineering Faculty Publications

This contribution presents a model analysis for the initiation of explosive emission; a phenomena that is observed at cathode surfaces under high current densities. Here, localized heating is quantitatively evaluated on ultrashort time scales as a potential mechanism that initiates explosive emission, based on a two-temperature, relaxation time model. Our calculations demonstrate a strong production of nonequilibrium phonons, ultimately leading to localized melting. Temperatures are predicted to reach the cathode melting point over nanosecond times within the first few monolayers of the protrusion. This result is in keeping with the temporal scales observed experimentally for the initiation of explosive emission.

Particle-In-Cell Based Parameter Study Of 12-Cavity, 12-Cathode Rising-Sun Relativistic Magnetrons For Improved Performance, Alireza Majzoobi, R. P. Joshi, A. A. Neuber, J. C. Dickens

Electrical & Computer Engineering Faculty Publications

Particle-in-cell simulations are performed to analyze the efficiency, output power and leakage currents in a 12-Cavity, 12-Cathode rising-sun magnetron with diffraction output (MDO). The central goal is to conduct a parameter study of a rising-sun magnetron that comprehensively incorporates performance enhancing features such as transparent cathodes, axial extraction, the use of endcaps, and cathode extensions. Our optimum results demonstrate peak output power of about 2.1 GW, with efficiencies of ~70% and low leakage currents at a magnetic field of 0.45 Tesla, a 400 kV bias with a single endcap, for a range of cathode extensions between 3 and 6 centimeters.

Simulation Study Of Hemt Structures With Hfo2 Cap Layer For Mitigating Inverse Piezoelectric Effect Related Device Failures, Deepthi Nagulapally, Ravi P. Joshi, Aswini Pradhan

Electrical & Computer Engineering Faculty Publications

The Inverse Piezoelectric Effect (IPE) is thought to contribute to possible device failure of GaN High Electron Mobility Transistors (HEMTs). Here we focus on a simulation study to probe the possible mitigation of the IPE by reducing the internal electric fields and related elastic energy through the use of high-k materials. Inclusion of a HfO₂ "cap layer" above the AlGaN barrier particularly with a partial mesa structure is shown to have potential advantages. Simulations reveal even greater reductions in the internal electric fields by using "field plates" in concert with high-k oxides

Spark Discharge Coupled Laser Multicharged Ion Source, Md. Haider A. Shaim, Hani E. Elsayed-Ali

Electrical & Computer Engineering Faculty Publications

A spark discharge is coupled to a laser multicharged ion source to enhance ion generation. The laser plasma triggers a spark discharge with electrodes located in front of the ablated target. For an aluminum target, the spark discharge results in significant enhancement in the generation of multicharged ions along with higher charge states than observed with the laser source alone. When a Nd:YAG laser pulse (wavelength 1064 nm, pulse width 7.4 ns, pulse energy 72 mJ, laser spot area on target 0.0024 cm²) is used, the total multicharged ions detected by a Faraday cup is 1.0 nC with …

Modeling The Crude Oil Scheduling Problem With Integration With Lower Level Production Optimization And Uncertainty, Jorge Asis Charbel Chebeir

LSU Master's Theses

This research is focused on the modeling and optimization of the crude oil scheduling problem in order to generate the most appropriate schedule for the unloading, charging, blending, and movement of crude oil in a refinery, which means obtaining the schedule that generates the lowest costs. Uncertainty, which is often present in these types of optimization problems, is also analyzed and taken into account for the resolution of crude oil scheduling problem. A comprehensive novel model is proposed to describe the upper level crude oil scheduling problem, generate an optimal solution for the mentioned problem, and allow integration with the …

Effect Of Heavy Vehicle On Conventional And Joint Work Zone Merges, James Joseph Dillard

LSU Master's Theses

Lane merges in construction work zones are guided by the Manual on Uniform Traffic Control Devices (MUTCD). The MUTCD typical lane closure guides merging vehicles from one lane into another; from the closed lane, where the construction work is taking place into the open lane. The conventional lane merge often creates conflicts for motorists because queues typically form in the open lane and aggressive drivers use this opportunity to drive in the closed lane as far as they can until forced to merge in the open lane. As a result, the conventional lane merge can create differential speeds and queue …

Wireless Localization In The Absence Of Gps, Hyundeok Kang

LSU Master's Theses

In this thesis, wireless localization is investigated based on multiple noisy estimates of the time-difference of arrival (TDOA) at each pair of the n >= 4 sensors with different but known locations using WiFi opportunistic signals. Our work is comprehensive and includes channel estimation, symbol detection, TDOA estimation, and location estimation. To mitigate the multipath issue induced by wideband signals, such as WiFi, frequency-division is employed to decompose the wideband RF signal into multiple non-overlapping narrowband signals. To minimize the adverse effects of the clock drift, time-division is proposed to divide the signal into multiple non-overlapping signals in the time …

Poly (Lactic Co-Glycolic) Acid Nanoparticles: Synthesis Using Millifluidic Chip And Interaction With Red Blood Cells, Sumit Libi

LSU Master's Theses

Nanoparticles (NPs) have recently been developed for application as drug carriers in different fields, including biomedical engineering. This study was focused on the use of a millifluidic chip for synthesis of polymeric poly (lactic co-glycolic acid) (PLGA) NPs and the understanding of PLGA NPs interaction and effect on red blood cells (RBCs). A method for NPs synthesis on a millifluidic chip was developed, exploiting the precise flow control offered by this device. PLGA NPs ranging from 230nm to 350nm in diameter were produced. Smaller NPs of lower polydispersity were synthesized at higher flow rates of the aqueous phase; increase in …

Evaluation Of Louisiana Friction Rating Table By Field Measurements, Yogendra Prasad Subedi

LSU Master's Theses

This study aims to evaluate the current Louisiana Department of Transportation and Development (LADOTD) friction rating table by field measurements and provide recommendations for the frictional mix design guidelines. The current friction rating table is based on the Polished Stone Value (PSV) of coarse aggregate as the only surface friction guideline in a wearing course mixture design, which is only one of many factors that affect the pavement surface friction. To achieve the objective, the pavement surface friction and texture properties were measured using Lock-Wheel Skid Trailer (LWST), Dynamic Friction Tester (DFT) and Circular Track Meter (CTM). Twenty two different …

Application Of Computational Fluid Dynamics To Near-Wellbore Modeling Of A Gas Well, Oscar Mauricio Molina

LSU Master's Theses

Well completion plays a key role in the economically viable production of hydrocarbons from a reservoir. Therefore, it is of high importance for the production engineer to have as many tools available that aid in the successful design of a proper completion scheme, depending on the type of formation rock, reservoir fluid properties and forecasting of production rates. Because well completion jobs are expensive, most of the completed wells are usually expected to produce as much hydrocarbon and as fast as possible, in order to shorten the time of return of the investment. This research study focused on the evaluation …

Near Total Resonant Light Absorption In A Graphene Monolayer At Multiple Tunable Wavelengths With Multilayer Structures, Iman Zand

LSU Master's Theses

Graphene could be potentially important for a broad range of photonic and optoelectronic applications. For such graphene-based applications it is critical to enhance the absorption of light in graphene monolayers in order to achieve near total absorption. Several structures have been proposed to enhance light absorption in graphene at visible and infrared wavelengths such as one-dimensional Fabry-Perot cavity structures, and photonic crystal slabs. Fabry-Perot cavity structures, which employ periodic Bragg mirrors, can lead to near total light absorption on resonance. However, such structures cannot achieve near complete absorption in graphene at multiple closely-spaced tunable wavelengths, which is potentially important for …

Stochastic Modeling Of Semantic Structures Of Online Movie Reviews, Limeng Pu

LSU Master's Theses

Facing the enormous volumes of data available nowadays, we try to extract useful information from the data by properly modeling and characterizing the data. In this thesis, we focus on one particular type of semantic data --- online movie reviews, which can be found on all major movie websites. Our objective is mining movie review data to seek quantifiable patterns between reviews on the same movie, or reviews from the same reviewer. A novel approach is presented in this thesis to achieve this goal. The key idea is converting a movie review text into a list of tuples, where each …

Driver Response And Safety Effect Of Three-Foot Bicycle Passing Laws, Nelida Andreina Herrera

LSU Master's Theses

The long and tragic history of vehicle-bicycle crashes in the United States has increasingly led to calls for legislative action to provide greater protections for bicyclists on the nation’s roadways. Among the most common of these actions are the three-foot passing laws. Recent history suggests that these laws may contribute to reducing the number of vehicular/bicycle-related collisions as well as their accompanying deaths and injuries, but few, if any, studies have shown how they substantively affect driver behavior. This thesis builds upon the results of recent research quantifying the effects of the three-foot passing laws by comparing key behavioral aspects …

An Exploration Of Plasmonics For Nanoparticle-Based Gene Delivery, Corey Raymond Landry

LSU Master's Theses

The spatiotemporal control of biological processes, especially cell growth and differentiation, remains one of the most compelling challenges in basic and clinical biomedical research. Fields as diverse as cancer therapy and regenerative medicine rely on spatial and temporal control of biochemical cues to achieve desired biological objectives. MicroRNA are attractive for highly-localized delivery applications because their instability in the cell restricts their biological effect to a small target area. These short, non-coding strands can be easily synthesized and modified for attachment and release from nanoparticle delivery vehicles. The research interest around microRNA therapies has produced a wide array of pathways …

Biofuel Production From Chinese Tallow Tree Seeds Using Microwave Technology, Mohamad Barekati Goudarzi

LSU Master's Theses

In-situ transesterification (simultaneous extraction and transesterification) of Chinese tallow tree seeds into methyl esters using two microwave systems were investigated in this study. In the first part, utilizing a batch system, parameters tested were catalyst concentration (1-4 wt.%), solvent ratio (2-6 v/w), reaction time (15-60 min) and temperature (50-70°C). A high degree of oil extraction and efficient conversion of oil to biodiesel were found in the proposed range. The process was further optimized in terms of product yields and conversion rates using Dohlert optimization methodology. Based on the experimental results and statistical analysis, the optimal production yield conditions for this …

A Low-Power Analog-Signal-Processing-Unit For Wirelessly-Powered Implantable Recording System, Qingyun Ma

All ETDs from UAB

Bio-electric signals convey information and phenomenon of the physiological activities of organisms, such as gene, protein sequences, neural, and cardiac rhythms. Various types of bio-electrical signals are extensively used for diagnostics as well as therapeutic interventions. Bio-electrical signals are low-amplitude, low-frequency and numerous unique properties (spiking, small oscillation, local field potential interference). The original signal's amplitude is so small that directly lower the output resolution of the analog to digital converter (ADC). Furthermore, the detected signals are corrupted with, local field potential, white noise, system noise, and other interference, so the relevant information could be easily missed during the digitization. …

Kinect Movements For Navigating A Virtual Exercise Environment By People With Mobility Impairments, Sean Pool

All ETDs from UAB

People with physical disabilities exhibit decreased physical activity compared to able-bodied individuals. While physical activity plays an integral role in the health of any individual, people with disabilities have difficulty attaining the quality and quantity of recommended exercise. A recent technique for encouraging physical activity in able-bodied individuals is to combine exercise equipment with a virtual exercise environment; as the user exercises, a video screen portrays the user moving through a virtual recreation of a real-world location. However, little has been done to adapt this technology, specifically the interface between user and environment, for people with mobility impairments. This project …

The Impact Of Roofing Material On Building Energy Performance, Ali Badiee

All ETDs from UAB

The last decade has seen an increase in the efficient use of energy sources such as water, electricity, and natural gas as well as a variety of roofing materials, in the heating and cooling of both residential and commercial infrastructure. Oil costs, coal and natural gas prices remain high and unstable. All of these instabilities and increased costs have resulted in higher heating and cooling costs, and engineers are making an effort to keep them under control by using energy efficient building materials. The building envelope (that which separates the indoor and outdoor environments of a building) plays a significant …

Dynamic Simulation Of Concrete Barriers, Adel Badiee

All ETDs from UAB

The American Association of State Highway and Transportation Officials (AASHTO) Bridge Specifications proposes “Yield Line Theory Analysis” in order to determine the structural capacity of concrete barriers based on their static strength. However, it appears that this method conservatively underestimates the structural capacity of concrete barriers to endure high vehicle impacts. Typically, this deficiency has been compensated for artificial reductions in bridge rail design loads used in the design code. Existing barrier design guidelines - static design methods incorporated into the AASHTO Bridge Specifications - are based upon National Cooperative Highway Research Program (NCHRP) Report 350. The Manual for Assessing …

A Distributed Diffusion-Driven Algorithm For Load Balancing In An Electrical Power Grid, Isaac Abhilash Ayyala

LSU Master's Theses

In this thesis we propose a distributed algorithm, based on diffusion, to balance loads on an electrical power grid, while maintaining stable operation (system’s ability to maintain bus voltages within preset bounds). This algorithm, called the Diffusion-driven Distributed Load Balancing (DDLB) algorithm, is implemented on the OMNET++ Discrete Event Simulator and the response of the physical grid is simulated on a load flow program, which together simulate a deployment of the DDLB algorithm on the grid. The electrical grid is represented as a graph whose nodes are buses and whose edges are power lines connecting buses. Each node (except the …

Multiscale Modeling Of Particle Transport In Petroleum Reservoirs, Layne Bryan French

LSU Master's Theses

Modeling subsurface particle transport and retention is important for many processes, including sand production, fines migration, and nanoparticle injection. In this study, a pore-scale particle plugging simulator is concurrently coupled with a streamline reservoir simulator to predict the behavior of particles in the subsurface. The coupled simulators march forward in time together. The automated communication between the two models enables the prediction of spatially and time dependent parameters that control the particle transport process. At each time step, the reservoir simulator provides the inlet velocity and particle concentration of the fluid suspension to the pore-scale model which outputs the permeability, …