Engineering Commons^™

Implementing A Linear Quadratic Spacecraft Attitude Control System, Daniel Kolosa

Masters Theses

This thesis implements a linear quadratic attitude control system for a low-thrust spacecraft. The goal is to maintain spacecraft alignment with a time-varying thrust vector needed for trajectory change maneuvers. A linear quadratic attitude control approach is used to maintain spacecraft pointing throughout flight. This attitude control strategy uses the thrust-acceleration input obtained from a linear quadratic optimal trajectory control model that simulates the trajectory of a spacecraft in orbit maneuvers. This attitude model simulates a CubeSat, a small satellite that is equipped with a low-thrust propulsion and attitude control system. An orbit raising and a plane change scenario is …

Modeling And Analysis Of Pca Workflow, Ewing Tiong

Masters Theses

Nursing shortage has been reported as a major problem faced not only by the United States but also by many other countries. One of the many interventions that has been used to curb nursing shortage is the increase in employment of Unlicensed Assistive Personnels (UAPs) as an alternative care delivery model. There are many types of UAP and one of them are Patient Care Assistants (PCAs). This research proposes a methodology to model and analyze the work ow of a PCA in terms of completing assigned tasks in a timely manner. The specific objectives of this research are to model …

Computer Aided Brain Tumor Edge Extraction Using Morphological Operations, Warqaa Shaher Alazawee

Masters Theses

Detecting the precise boundary of the area containing a recognized brain tumor is a complex problem and must be addressed since it applies to many medical modalities and tumor types. The objective of this thesis is to provide an efficient algorithm for detecting edges of brain tumors to help neurosurgeons identify the border of the critical area and distinguish the precise margin of the tumor from the rest of the brain tissue during the surgery. This thesis work exploits MRI brain tumor images as a tool to aid surgeons. MRI image segmentation is an essential step as a preliminary process …

Formulation And Evaluation Of Soy Polymer Based, Gravure Printed Resistive Inks For Applications In Printed Electronics, Bhushan Hiralal Patil

Masters Theses

Today, the majority of the commercially available conductive inks are formulated using expensive metallic particles, such as silver and gold. Most of the inks use volatile solvents in the formulation, which are hazardous to the environment as emission of VOCs is the major concern. In the case of water-based inks, usually petroleum-based acrylic polymers are used. Apart from being nonrenewable raw materials, acrylic polymers are carcinogenic in nature. Also, acrylic polymers are used in a variety of applications, such as the automotive, medical device, paint, and adhesive industries. Often times, the ink industry has to compete with other industries for …

Truckload Carrier Selection, Routing And Cost Optimization, Zhixin Han

Masters Theses

The aim of this thesis was to investigate the routing decision combined with common carrier selection for dedicated contract carriers to reduce full truckload routing cost on pickup and delivery service within time windows in a multiple depots scenario. Mixed Integer Programming and some heuristic algorithms such as the genetic algorithm and annealing algorithm have been successfully used to solve vehicle routing problems for a long time, but researchers seldom simultaneously focus on issues of carrier selection, multiple depots, time window, and the government regulations for a dedicated contract carrier. Therefore, this thesis involved constraints of pickup and delivery with …

The Economic Implications Of Evolving Aviation Funding Policy In Tennessee, Hunter Pressley Mccracken

Masters Theses

The majority of state funding for capital improvements at Tennessee’s general aviation and commercial airports comes through grants awarded from the Tennessee Transportation Equity Trust Fund (TETF). Through a 4.5 percent sales and use tax on the consumption of aviation fuel, users help to fund the continued improvement and maintenance of aviation facilities around the state. Aircraft refueling operations associated with the FedEx “SuperHub” in Memphis were responsible for two-thirds of the TETF’s revenue for Fiscal Year 2014. In response to speculation that FedEx would relocate its refueling operations to reduce its fuel tax liability, the Tennessee General Assembly passed …

Spatial Variation In Fine Sediment And Microbial Transport Along Stream Cross Sections: Implications To Modeling And Monitoring, Thomas Michael Walton

Masters Theses

Spatial variations in suspended concentrations of fine sediment and indicator bacteria in streams is noted as a source of uncertainty in various applications of water quality datasets. Without proper analysis of the persistence and reasoning for this variance in natural systems, a finer resolution of model calibration is necessary to account for spatial variation in stream cross sections. This level of calibration has become of utmost importance due to technological advancements presenting the ability for water quality modeling frameworks to generate a much finer resolution of outputs. While the importance of model calibration has been noted for remediating levels of …

Control Of Cation Ordering In Zinc Tin Nitride And In-Situ Monitoring Of Growth, Brian Christopher Durant

Masters Theses

Semiconducting materials with a band gap around 1.5 eV are very much sought after due to their close match to the solar spectrum. However, some compounds that have shown promise for highly efficient solar cells contain rare, expensive, and sometimes toxic elements, such as indium and gallium. As such, a search for earth abundant materials has become more prominent recently. One such earth abundant semiconducting material that has garnered interest is ZnSnN₂. It has been shown through previous studies that there is the possibility of continuously tuning the band gap between 1.0 and 2.0 eV by controlling the …

Design Of Digital Down Converter Chain For Software Defined Radio Systems On Fpga, Nagarjun Marappa

Masters Theses

Modern communication systems have increasingly attempted to trade off the digital signal processing for analog circuitry. In performing this tradeoff, advanced algorithms have been implemented in both custom programmable hardware and in software; such systems are commonly called Software Defined Radios (SDR). Advanced software defined radios consist of highly configurable hardware and computers used as digital signal processing (DSP) platforms that provide the technology for realizing current and future generations of digital wireless communication infrastructure. Many sophisticated signal processing tasks are performed in SDR, including compression algorithms, channel estimation, equalization, forward error correction and protocol management. This research has focused …

A High Performance Architecture For An Exact Match Short-Read Aligner Using Burrows-Wheeler Aligner On Fpgas, Dana Abdul Qader

Masters Theses

Due to modern DNA sequencing technologies vast amount of short DNA sequences known as short-reads is generated. Biologists need to be able to align the short-reads to a reference genome to be able to make scientific use of the data. Fast and accurate short-read aligner programs are needed to keep up with the pace at which this data is generated. Field Programmable Gate Arrays have been widely used to accelerate many data-intensive bioinformatics applications.

Burrows-Wheeler Transform has been used in the theory of string matching which has led to the development of many short-read alignment programs. This thesis presents a …

An Integrated Framework For Cardiac Sounds Diagnosis, Zichun Tong

Masters Theses

The Phonocardiogram (PCG) signal contains valuable information about the cardiac condition and is a useful tool in recognizing dysfunction and heart failure. By analyzing the PCG, early detection and diagnosis of heart diseases can be accomplished since many pathological conditions of the cardiovascular system cause murmurs or abnormal heart sounds. This thesis presents an algorithm to classify normal and abnormal heart sound signals using PCG. The proposed analysis is based on a framework composed of several statistical signal analysis techniques such as wavelet based de-noising, energy-based segmentation, Hilbert-Huang transform based feature extraction, and Support Vector Machine based classification. The MATLAB …

Morphology Based Framework For Improved Driver's Visibility In Inclement Weather Conditions, Saleem Farhood Hussein

Masters Theses

The U.S. Department of Transportation reports that on average there are 5,870,000 vehicle accidents each year. Twenty-three percent (23%) of these accidents are attributed to weather conditions with an annual average of more than 6,000 people are killed and 480,000 people are injured. Weather-related accidents occur mainly because of the low visibility on the roads under inclement conditions such as snow, rain and fog. While these conditions can be predictable and individuals try to avoid driving in inclement weather, there are circumstances that require driving in such conditions such as emergency responders or when the severity of the storm has …

Signage Recognition Based Wayfinding System For The Visually Impaired, Abdullah Khalid Ahmed

Masters Theses

Persons of visual impairment make up a growing segment of modern society. To cater to the special needs of these individuals, society ought to consider the design of special constructs to enable them to fulfill their daily necessities. This research proposes a new method for text extraction from indoor signage that will help persons of visual impairment maneuver in unfamiliar indoor environments, thus enhancing their independence and quality of life.

In this thesis, images are acquired through a video camera mounted on glasses of the walking person. Frames are then extracted and used in an integrated framework that applies Maximally …

Design Of A New Digital Relay For Transmission Line Fault Detection, Classification And Localization Based On A New Composite Relay And Artificial Neural Network Approach, Ahmed Sabri Altaie

Masters Theses

This thesis focuses on new approach to detect, classify, and localize the fault in transmission line. Firstly, fault detection was carried out using the New Composite Relay (CR) which, has different characteristics and the ability to detect any type of fault including series faults. Secondly, fault classification was conducted using the Feed Forward Artificial Neural Network (FFANN). In addition, the fault classification led to the investigation of the best use of the FFANN. The data used come from MATLAB/SIMULINK three phase series compensated network. The results obtained using FFANN, were compared with the type of the fault that have been …

Simulation Of Lateral Migration And Sedimentation Of A Flexible Fiber In A Vertical Weak Shear Flow, Ali Ibrahim Neamah Neamah

Masters Theses

This research is a thorough numerical investigation and critical analysis of lateral migration of a deformable particle settling in a vertical weak shear flow. Under the vertical weak shear fluid, the deformable particle may move either to the coagulation area, or the dispersion area, depending on Reynolds numbers, shear Reynolds number, fiber flexibility, and aspect ratio. In this study, a lattice Boltzmann equation is used to solve Navier-Stokes equation and a flexible particle method is employed to attack the problem of motion of a flexible fiber. A bounce-back rule is used to deal with moving boundaries interacting with fluids. Several …

Effect Of Particle Morphology On The Deformation Behavior Of Sand Under Monotonic Loading Conditions, Alexia Rose Leib

Masters Theses

When a projectile hits sand, the projectile places high stresses on the sand surface. Granular materials at high stresses are liable to crushing. The pressure at which crushing occurs depends greatly on particle shape and relative density. These parameters also greatly influence the changes in particle shape and size after crushing. Additionally, projectiles fired at extremely high velocities are preceded by a pressure wave. This pressure wave can crush granular material before the projectile ever touches the surface. If the sand has been crushed and its inherent particle properties changed before projectile impact, the projectile may not behave as expected. …

Icloudecg: A Mobile Cardiac Telemedicine System, David S. Clifford

Masters Theses

With rising healthcare costs and a substantially growing number of patients 65 or over, the benefits of telemedicine and patient self-monitoring systems are becoming increasingly evident. Patients, physicians, hospitals, and even insurance providers benefit from vigilant, cost-effective patient monitoring systems. This thesis describes the development of a portable, smart-phone connected system for continuous cardiac monitoring. The system is capable of continuously monitoring the conditions of the heart, automated detection of cardiac arrhythmias, and real-time notifying patients and physicians of the detected abnormalities. The system consists of four main subsystems: 1) a Bluetooth capable chest-strap ECG, 2) an Android-enabled mobile device, …

Incorporation Of High-K Hfo2 Thin Films In A-Igzo Thin Film Transistor Devices, Aaron Hamilton Bales

Masters Theses

In this study, HfO2 [hafnium oxide] thin films are investigated extensively as part of indium gallium zinc oxide (IGZO) thin film transistor (TFT) devices. They are incorporated into the TFTs, both as a gate insulator and a passivation layer. First, the HfO2 [hafnium oxide] films themselves are investigated through an annealing study and through I-V and C-V measurements. Then, HfO2 [hafnium oxide] is suggested as a replacement for commonly used SiO2 [silicon dioxide] gate insulator, as it has a dielectric constant that is 4 – 6 times higher. This higher dielectric constant allows for comparable TFT performance at a lower …

Modeling And Simulation Of A Prototypical Advanced Reactor, Xiaotong Liu

Masters Theses

Current online risk monitors provide a point-in-time estimate of the system risk given the current plant configuration (e.g., equipment availability, operational regime, environmental conditions). However, these risk monitors do not account for plant- specific normal, abnormal, and deteriorating states of active components and systems. The lack of operating experience with proposed advanced reactor designs limits our ability to estimate the probability of failure (POF) of key components. Incorporation of unit-specific estimates of POF into dynamic probabilistic risk assessment (PRA) has the potential to enable real-time decisions about stress relief and to support effective maintenance planning while ensuring investment protection. The …

Heuristic Solution For Separated Manufacturing Process, James Dee Davis

Masters Theses

Downtime is a major issue for manufactures. Downtime may occur from breakdowns, quality issues, lack of manpower, lack of materials, or in this case a lack of storage containers. A manufacturing system was studied that consists of an injection machine that supplies two assembly lines. The injection machine suffered from frequent downtime from lack of containers. The process was analyzed for root cause of downtime. After analysis of the system it was found that the injection process had high variability in production quantity and quality. The scheduling scheme called for production until all available containers were full regardless of actual …

Rapid Dissolution For Destructive Assay Of Nuclear Melt Glass, Jonathan Allen Gill

Masters Theses

This study evaluates four methods for dissolving complex glassy debris resulting from nuclear detonations. The samples of interest simulate the glassy debris generated from a nuclear detonation’s fireball coming in contact with solid masses. Each method attempts to achieve dissolution through different approaches involving either acid digestion, alkaline digestion, or molten salt fusion. Two of the four methods were modified to retain all elements of the debris or surrogate debris. This retention is critical to the proportional relationships used in identifying fuel types and designs of nuclear weapons. Analysis is conducted with an inductively coupled time of flight mass spectrometer …

Modeling Route Choice Of Utilitarian Bikeshare Users From Gps Data, Ranjit Khatri

Masters Theses

This research examines the behavior of bikeshare users from Grid Bikeshare Program in Phoenix, Arizona under two behavioral frameworks: facility usage assessment and route choice assessment. The analysis is performed for the two different categories of subscribers: registered and casual subscribers. This is the first study that uses the real-time GPS data from bikeshare users to model their route preferences. The data used for this study were obtained from 9,101 trips made by 1,866 bikeshare. An important aspect of this bikeshare is that it allows non-station origin and destinations. The GPS points collected from the trips made by bikeshare users …

Effects Of Varus Knee Alignment And Using Toe-Cages On Frontal Plane Knee Biomechanics In Stationary Cycling, Guangping Shen

Masters Theses

Effects of varus knee alignment on the internal knee abduction moment (KAM) in walking has been widely studied. KAM has been shown to be closely associated with the development of medial knee osteoarthritis (OA). Despite the importance of the knee alignment, no studies have explored its effects on knee frontal plane biomechanics during stationary cycling. The purpose of this study was to examine the effects of varus knee alignment and using a toe-cage on the knee frontal plane biomechanics during stationary cycling. Eleven participants in each of the varus and neutral groups participated in the study. The participants performed in …

A Hardware Based Audio Event Detection System, Jacob Daniel Tobin

Masters Theses

Audio event detection and analysis is an important tool in many fields, from entertainment to security. Recognition technologies are used daily for parsing voice commands, tagging songs, and real time detection of crimes or other undesirable events. The system described in this work is a hardware based application of an audio detection system, implemented on an FPGA. It allows for the detection and characterization of gunshots and other events, such as breaking glass, by comparing a recorded audio sample to 20+ stored fingerprints in real time. Additionally, it has the ability to record flagged events and supports integration with mesh …

Non-Residential Pedestrian Access To Transit Systems: A Gis Modeling Application, Luis Miguel Taboada

Masters Theses

The success of a city’s urban transit system relies on the efficacy of its pedestrian infrastructure. A functional and access-oriented pedestrian network translates into safer pedestrian travel, increased demand in transit ridership, increases in commerce patronage, and reduced motorized travel (i.e., less congestion, and less vehicle emissions). Prioritization and allocation of sidewalk construction improvements are not always done in conjunction with transit service provisions. As a result, potential destinations are left inaccessible to pedestrians using the transit system. This study is motivated by concurrent research involving sidewalk improvement prioritization methods, within the scope of home-based work pedestrian transit trips. This …

Optimization Of Titanium Liquid/Gas Diffusion Layers In Proton Exchange Membrane Electrolyzer Cells, Stuart Mccoy Steen

Masters Theses

Polymer electrolyte membrane electrolyzer cells (PEMECs), which are reverse PEM fuel cells (PEMFCs), are effective energy storage medium by producing hydrogen/oxygen from water using electricity from renewable energy sources. This is due in part because of its efficiency, high energy density, compact design, and large capacity. In a PEMEC, a liquid/gas diffusion layer (LGDL) is located between the catalyst layer and the current distributing flow field. The LGDL is expected to transport electrons, heat, and reactants/products to and from the catalyst layer with minimum voltage, current, thermal, interfacial, and fluidic losses. Carbon materials (carbon paper or carbon cloth), typically used …

Impurity Effects In All-Vanadium Redox Flow Batteries, Andrew William Burch

Masters Theses

In this dissertation, the effects of VOSO₄ [vanadyl sulfate] source and impurities on the beginning-of-life (BOL) performance of an all-vanadium redox flow battery (VRFB) are explored. Battery performance was monitored at 50% state of charge (SOC) using electrolyte with VOSO₄ purities of 99%, 99.9% and 99.99% by weight. At cell potentials of 1.23V, the least pure solution yielded the lowest current density of 280 mA/cm² [square centimeter] and the most pure solution yielded the highest, 560 mA/cm². The voltage efficiencies and charge-discharge capacities were shown to follow the same trends. Scanning electron microscopy (SEM) images …

Implementation Of A Neuromorphic Development Platform With Danna, Jason Yen-Shen Chan

Masters Theses

Neuromorphic computing is the use of artificial neural networks to solve complex problems. The specialized computing field has been growing in interest during the past few years. Specialized hardware that function as neural networks can be utilized to solve specific problems unsuited for traditional computing architectures such as pattern classification and image recognition. However, these hardware platforms have neural network structures that are static, being limited to only perform a specific application, and cannot be used for other tasks. In this paper, the feasibility of a development platform utilizing a dynamic artificial neural network for researchers is discussed.

Ion Irradiation Characterization Studies Of Max Phase Ceramics, Daniel William Clark

Masters Theses

The family of layered carbides and nitrides known as MAX phase ceramics combine many attractive properties of both ceramics and metals due to their nanolaminate crystal structure and are promising potential candidates for application in future nuclear reactors. This thesis reports on the background, design, and analysis of an experiment focused on determining the effects of energetic heavy ion irradiations on polycrystalline samples of titanium silicon carbide 312, titanium aluminum carbide 312, and titanium aluminum carbide 211. The irradiation conditions consisted of ion doses between 10 and 30 displacements per atom at temperatures of 400 and 700 degrees Celsius, conditions …

Dividing And Conquering Meshes Within The Nist Fire Dynamics Simulator (Fds) On Multicore Computing Systems, Donald Charles Collins

Masters Theses

The National Institute for Standards and Technology (NIST) Fire Dynamics Simulator (FDS) provides a computational fluid dynamics model of a fire, which can be visualized by using NIST Smokeview (SMV). Users must create a configuration file (*.fds) that describes the environment and other characteristics of the fire scene so that the FDS software can produce the output file (*.smv) needed for visualization.The processing can be computationally intensive, often taking between several minutes and several hours to complete. In many cases, a user will create a file that is not optimized for a multicore computing system. By dividing meshes within the …