Engineering Commons^™

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 …

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 …

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 …

Bankfull Geomorphic Relationships And Hec-Ras Assessment In Small Catchments Of The Cumberland Plateau Ecoregion, Ryan Lee Hodges

Masters Theses

There is a great need for state governments to have effective watershed restoration and mitigation efforts to return degraded ecosystems to a stable, healthy condition. Given the growing investment in stream restoration efforts, there is an urgent need for tools to assess and improve the effectiveness of restoration efforts at local, state, and nationwide scales. In 2000 there was less than ten stream restoration permits provided by the state of Tennessee and has increased each year with almost forty permits issued in 2013. To better achieve successful stream restoration, appropriate channel designs must be used that reflect the hydraulic conditions …

Removal Of Trace Organic Compounds In Domestic Wastewater Using Recirculating Packed-Bed Media Filters, Brittani Nikole Perez

Masters Theses

Pharmaceuticals and personal care products (PPCPs) are commonly detected in the environment resulting from their survival from conventional wastewater treatment systems. More information is needed about the fate and transfer of these trace organic compounds in domestic wastewater and their associated risks so that efficient strategies for their removal can be developed for both large/small scale treatment systems. This study aimed to determine whether onsite wastewater treatment systems were capable of providing PPCP removal, in addition to quantifying different forms of removal (biodegradation/sorption). A column study was constructed to determine the removal efficiencies of 3 target PPCPs, endocrine disrupting compound …

Kinetic And Thermodynamic Modeling Of Long Term Phase Stability In Alloy 800h Subjected To Lwr Core Conditions, Wayne Ethan Pratt

Masters Theses

An in depth literature review of Incoloy Alloy 800H was conducted and presented to summarize the current understanding of microstructural evolution under irradiation and secondary phase precipitate stability. Due to a lack of radiation induced segregation (RIS) data for Alloy 800H, Isopleth sections varying Cr, Ni, Ti, and Si were generated from a computational thermodynamics approach using ThermoCalc and analyzed to compensate for knowledge related to radiation induced precipitates (RIP’s). These isopleths were analyzed for a composition range based off previous knowledge of RIS tendencies in austenitic stainless steels. Analysis of four major binary phase diagrams and complex phase diagrams …

Characterization Of Convective Heat Transfer Coefficients Of A Self-Aspirated Hot Gas Temperature Probe, Samuel David Stephens

Masters Theses

The objective of this work is to provide a Nusselt Number in a Reynolds Number and Prandtl Number correlation for various surfaces of an aspirated total temperature probe exposed to high temperature flow. The experiment discharged thermally stabilized dry air through large scale models of the probe surfaces in a blow-down wind tunnel and a direct connect facility. The model contained electrically heated sections exposed to the flow which were thermally insulated and instrumented with thermocouples. Experimental data were recorded for several Reynolds numbers and heater positions across three configurations. Uncertainty analysis was performed by the Monte Carlo uncertainty propagation …

Extending The Lean Limit Of Methane-Air Mixtures By Oxygen, Nitrogen And Carbon Dioxide Injection In The Gap Of The Spark Plug’S Electrodes, Artem Alexandrov Temerev

Masters Theses

An experimental investigation is carried out to investigate the feasibility of extending the lean limit for methane–air mixtures by injecting oxygen and other gases such as nitrogen and carbon dioxide in the area between spark plug electrodes. Additionally, the effect of oxygen injection on exhaust gas recirculation (EGR) is investigated. The pressure in the chamber and the equivalence ratio of the mixture are varied from 0.35 MPa to 1.03 MPa and 0.46 to 1.0, respectively. Delco 12620540 spark plug is used as the ignition source and the gas injection into spark plug gap is accomplished through a 0.159-cm OD stainless …

Evaluation Of Fuel Flow Measurement Uncertainty In A Turbine Engine Test Cell, Paul Andrew Wright

Masters Theses

The evaluation of measurement uncertainty is an essential part of measurement and data analysis. Measurement uncertainty is itself a measure of the “goodness” of the measured data and helps the analyst to make decisions based on the data. In the turbine engine testing world, accurate measurement of fuel flow is critical. Specific fuel consumption is a combination of thrust and fuel flow and is used to calculate the allowable payload and range of an aircraft as well as the cruising speed. Naturally, test customers (engine manufacturers, aircraft designers, and operators) are very sensitive to the accuracy of fuel flow measurement. …

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 …

Mixing Metals For Magic Materials: Analysis Of Binary Eutectic Alloys For Metamaterial Applications, Ethan Elder Fox

Masters Theses

Uses of metamaterials, also known as negative index materials (NIMs), are wide ranging and include lenses that have a resolution beyond the diffraction limit, incredibly small antenna, and cloaking devices for optical, infrared, and microwave wavelengths.

The unique properties of metamaterials are not found in any naturally occurring material. By having simultaneously negative values for ε [electrical permittivity] and μ [magnetic permeability], a metamaterial can have a negative index of refraction over a certain frequency band. The unique properties of negative index materials emerge chiefly from their highly ordered structure.

Binary eutectic alloys have the potential to be used as …

Cmos Current-Frequency Signal Processing Unit For Bioimplantable Sensors, Madeline Nicole Threatt

Masters Theses

Over the past few decades, implantable monitoring of glucose, lactate acid, and pH monitoring has become a viable replacement for stationary monitoring. Implantable biosensing requires biosensors in conjunction with corresponding potentiostats and a signal processing unit to translate the data information to a more versatile, transmittable form. This thesis presents a current-mode signal processing unit (SPU) that merges the simplicity of a charging capacitor in feedback topology with the accuracy of a delta-sigma modulator to create a pulse train with a frequency proportional to the input current. The SPU was realized in a 0.18 µ[micro]m bulk CMOS process.

Durability Of Lightweight Concrete For Bridge Decks, Andrew Mccullough Wagner

Masters Theses

As concrete durability becomes a higher priority for departments of transportation’s acceptability of concrete for bridge decks, consideration of resistance to the penetration of chloride ions has become a key consideration in defining durability. For years the “Rapid Chloride Ion Penetration (RCP) test has been the accepted standard to measure penetrability of concrete to chloride ions. With the movement to use chloride ion penetrability as a part of acceptance criteria for a concrete mix, use of the newer and easier Surface Resistivity (SR) test as an alternative to the slower, more complicated “Rapid Chloride Ion” test became a desirable option. …

Economic And Environmental Optimization In The Supply Of Switchgrass In Tennessee, Jia Zhong

Masters Theses

The low efficiency of collection, storage and transportation in the switchgrass supply chain has hindered the commercialization of a switchgrass-based biofuel industry, even given its ecological and environmental advantages in carbon sequestrate, soil quality, water use, and pollution pressure. Thus, designing a switchgrass-based supply chain balancing both environmental and economic performance is important to expedite the development of the cellulosic biofuel industry to meet the national energy plan.

The objectives of this study are to 1) determine economic cost and multiple environmental outcomes in feedstock supply chains and 2) identify the relation between the economic and environmental performances. The first …

Integration Of Maintenance Into Design And Sustainability Of Buildings, Dinesh Reddy Patlolla

Masters Theses

Custodial maintenance is an important aspect of operational maintenance in a facility. Custodial maintenance improves an organization's discipline, performance and keeps surroundings healthy. That being said maintaining clean surroundings involves considerable cost. Custodial maintenance cost forms significant portion of building budgets, however these costs are often neglected. This research deals with the identification of variables that affect maintenance costs in a facility and reduction of maintenance costs. The minimization of cost is done by giving the administrator or facilities manager the option of selecting alternatives in frequency of maintenance, level of maintenance and the number of people required to complete …

A Low-Power, Laser-Based Delta-Sigma Modulator For The Measurement Of Atmospheric Gas Composition, Christopher Edward Crowder

Masters Theses

With the increased attention on monitoring the atmosphere’s gas composition, new ways of accurately measuring these concentrations are needed. Along with the needed increase in measurement accuracy; size, space, and power reduction is also essential in modern systems. As semiconductor technology has advanced, the abilities to meet the previously mentioned criteria are becoming more realizable.

Instrumentation used to measure the atmosphere’s composition is traditionally large, taking up much needed space and using larger amounts of power. While the larger instrumentation provides the necessary accuracy, the other constraints are sacrificed. For this reason, a smaller, yet highly accurate solution is needed. …