Digital Commons Network^™

Heat Transfer Analysis Via Rate Based Sensors, Jake Erik Plewa

Masters Theses

This work presents an integrated rate-based sensor and method for resolving the surface heat flux of a fundamental inverse heat conduction problem without numerical regularization or differentiation in a semi-infinite geometry that additionally accounts for thermocouple delay due to its intrinsic time constant. The sensor uses well-designed analog filters to directly regularize raw voltage data to eliminate the need for numerical regularization methods. The sensor can also be used in a series of well-designed voltage-rate interfaces that directly measure the voltages from in-depth thermocouples, which are used in conjunction with the thermocouple calibration curve to provide higher-time derivatives of the …

Characterizing The Concentration, Duration, And Frequency Of Turbid Events In Tennessee Streams: Potential For Macroinvertebrate Impairment, Robert Ryan Woockman

Masters Theses

The impairment of lotic systems due to siltation is one of the most common factors leading to a stream being placed on the 303d list. Once a stream reach is placed on the 303d list, a state’s environmental regulatory agency must then develop sediment total maximum daily loads (TMDLs). However, a deficiency exists in available methods for assessing biotic response to siltation, creating the inability to set TMDLs functionally related to cause of impairment. Water quality sondes can collect voluminous amounts of turbidity data and stage data at intervals that can be used to characterize concentration, duration, and frequency (CDF) …

Design Of A Neutron Detector Capable Of Replacing He-3 Detectors Utilizing Thin Polymeric Films, Matthew J. Urffer

Masters Theses

There exists a significant need to develop a new neutron detection system which would reduce the dependency on the current He-3 based detectors for Domestic Nuclear Detection Office (DNDO) applications. One of the technologies being developed is the use of Li-6 (thermal cross section of 940 barns) in scintillating polymeric thin films. The purpose of this research is to provide a framework for the characterization of thin polymeric films in terms of meeting the detection requirements set forth by the governing bodies, most notability a detector count rate of 2.5 cps/ng with and only misclassifying a neutron as a gamma …

Processing, Microstructures, And Mechanical Behavior Of High-Entropy Alloys, Zhi Tang

Masters Theses

Recently, high-entropy alloys (HEAs) have attracted increasing attentions because of their unique compositions, microstructures, and adjustable properties. In this work, microstructure and phase composition of the AlCoCrFeNi high-entropy alloy (HEA) were studied in as-cast and heat-treated conditions. Using a combination of Electron Backscatter Diffraction (EBSD), X-ray energy spectroscopy analysis, and synchrotron X-ray diffraction techniques, two nonequilibrium phases were identified in the as-cast condition: BCC_A2 and B2. Long-term heat treatment transformed these nonequilibrium phases into four equilibrium phases: FCC_A1, BCC_A2, B2, and σ [sigma] phase. The electron microscopic results were consistent with thermodynamic simulations of the equilibrium …

Lignin Yield Maximization Of Lignocellulosic Biomass By Taguchi Robust Product Design Using Organosolv Fractionation, Anton Friedrich Astner

Masters Theses

Lignin, a byproduct of the organosolv pretreatment process using lignocellulosic biomass from switchgrass (Panicum virgatum) and tulip poplar (Liriodendron tulipifera) is currently being explored for its potential use in the production of value-added chemicals and biobased polymers. Pretreatment is one of the most expensive processing steps in cellulosic biomass conversion. Optimization of the process is one of the major goals of the biomass-toethanol conversion process. Taguchi Robust Product Design (TRPD) provides an effective engineering experimental design method for optimizing a system and designing products that are robust to process variations. Given the results of several preliminary …

Predicting Enzyme Targets For Optimization Of Metabolic Networks Under Uncertainty, David Christopher Flowers

Masters Theses

Recently, ensemble modeling was applied to metabolic networks for the sake of predicting the effects of genetic manipulations on the observed phenotype of the system. The ensemble of models is generated from experimental wild-type flux data and screened using phenotypic data from gene overexpression and knockout experiments, leaving predictive models. The need for data from multiple genetic perturbation experiments is an inherent limitation to this approach. In this investigation, ensemble modeling is used alongside elementary mode analysis to attempt to predict those enzymatic perturbations that are most likely to result in an increase in a target yield and a target …

Validation Of Weak Form Thermal Analysis Algorithms Supporting Thermal Signature Generation, Elton Lewis Freeman

Masters Theses

Extremization of a weak form for the continuum energy conservation principle differential equation naturally implements fluid convection and radiation as flux Robin boundary conditions associated with unsteady heat transfer. Combining a spatial semi-discretization via finite element trial space basis functions with time-accurate integration generates a totally node-based algebraic statement for computing. Closure for gray body radiation is a newly derived node-based radiosity formulation generating piecewise discontinuous solutions, while that for natural-forced-mixed convection heat transfer is extracted from the literature. Algorithm performance, mathematically predicted by asymptotic convergence theory, is subsequently validated with data obtained in 24 hour diurnal field experiments for …

Evaluation Of Tagging Techniques Gamma-Decay Probabilities Using The Surrogate Method, Timothy Lee Reed

Masters Theses

A detailed analysis of the statistical and discrete [gamma]-decay tagging techniques was conducted using the absolute surrogate and surrogate ratio method (SRM) to obtain the 92Mo(n,[gamma]) cross section in an equivalent neutron energy range of 80 to 880 keV. Excited 93Mo and 95Mo nuclei were populated using (d,p) reactions on 92Mo and 94Mo targets, respectively. The absolute surrogate 92Mo(n,[gamma]) cross sections disagreed with evaluated neutron capture cross section data by as much as a factor of 4 using the statistical tagging approach, whereas the discrete [gamma]-decay tag absolute surrogate cross section disagreed with the evaluated neutron capture cross section by …

Impacts Of Beetle Kill On Modeled Streamflow Response In The North Platte River Basin, Jordan Andrew Rudolph

Masters Theses

A beetle epidemic has been sweeping its way across the western United States and into portions of southern Canada that has caused millions of acres of forests to ultimately die. This beetle outbreak, that many have come to know simply as “beetle kill”, has caused many scientists to feel that such dramatic changes in land cover could potentially alter the hydrology throughout much of the West. One of the most important hydrological processes that beetle kill has the potential to impact is streamflow. This paper attempts to evaluate the hydrological impacts on streamflow from land cover change due to beetle …

Exploring Anaerobic Reductive Dechlorination At Low Ph Environments, Yi Yang

Masters Theses

Chlorinated aliphatic hydrocarbons (CAHs), such as tetrachloroethene (PCE) and trichloroethene (TCE), are ubiquitously pollutants in aquifer sediments and groundwater due to their heavy usage in industry and inappropriate disposal in the last century. Among about 1300 NPL (National Priorities List) sites, PCE and TCE are the two most frequently detected hazardous contaminants.

Engineered bioremediation, including biostimulation and bioaugmentation, is a promising technology to clean those PCE and/or TCE contaminated sites. However, in many contaminated groundwater systems and hazardous waste sites, pH can be lower than 5 to 6. And release of HCl (strong acid) from anaerobic reductive dechlorination may lower …

Melt Blown Poly(Lactic Acid) For Application As A Tissue Engineering Scaffold, William Horst Gazzola

Masters Theses

Poly(lactic acid) (PLA) was melt blown (MB) under varying processing conditions to create webs with micro and nano-architecture. Processing parameters varied were primary air flow rate and collector distance. In total, twenty-one webs were produced and the physical properties of the webs were investigated including, mean fiber diameter and fiber diameter distribution, mean pore diameter and pore size distribution, web thickness, degree of crystallinity, tensile modulus and degradation rate. Four webs, two with micro and two with nano-architecture, thought suitable for use as tissue engineering scaffolds were selected for seeding with A375 human malignant melanoma cells. Cell culture was conducted …

Application Of Highway Capacity Manual 2010 Level-Of-Service Methodologies For Planning Deficiency Analysis, James Oliver Ensley

Masters Theses

Influence on investment in the infrastructure is critical for decision-making by State planning departments. Judgments which are made for funding purposes and are based on limited data analysis by states can results in economic disasters for the state and nation. The Tennessee Department of Transportation (TDOT) uses the Evaluation of Roadway Efficiency (EVE) database to prioritize the importance of roadway projects in the state. In addition, EVE is also used as a method to provide deficiency analysis results for roadways in the state. This study will add support to the methodology of the current decision-making process in regards to Tennessee …

Utilization Of Rainwater As A Supplementary Water Source For Cooling Tower Makeup: A Sustainability Strategy For Potable Water Use Reduction, Elizabeth Stassun Costello

Masters Theses

The use of rainwater as a supplementary water source for cooling water makeup was explored in an effort to reduce the potable water demand of theUniversityofTennessee’sKnoxvillecampus. A water quality analysis involving the measurement of parameters relevant to cooling tower operation was conducted on tap water currently used for makeup supply and rainwater collected from the roof of a campus building. In anticipation of limited rainwater supplies due to issues of catchment surface area, collection efficiency, storage capacity, and climatic conditions, blends of rainwater and tap water were also analyzed. The dissolved solids concentration of the rainwater was significantly lower than …

Exploration Of Neural Structures For Dynamic System Control, Scott Frederick Hansen

Masters Theses

Biological neural systems are powerful mechanisms for controlling biological sys- tems. While the complexity of biological neural networks makes exact simulation intractable, several key aspects lend themselves to implementation on computational systems.

This thesis constructs a discrete event neural network simulation that implements aspects of biological neural networks. A combined genetic programming/simulated annealing approach is utilized to design network structures that function as regulators for continuous time dynamic systems in the presence of process noise when simulated using a discrete event neural simulation.

Methods of constructing such networks are analyzed including examination of the final network structure and the algorithm …

Estimates Of Glacier Mass Loss And Contribution To Streamflow: Wind River Range (Wyoming, Usa), Jeffrey Allen Marks

Masters Theses

The Wind River Range is a continuous mountain range approximately 160 km in length in west-central Wyoming. The Wind River Range is host to roughly 680 snow and ice bodies with 63 of these considered glaciers including seven of the ten largest glaciers in the American Rocky Mountains. The presence of glaciers results in meltwater contributions to streamflow during the late summer (July, August, and September – JAS) when snowmelt is decreasing, temperatures are high, precipitation is low, and irrigation demand continues. Most studies indicate that the glaciers in the Wind River Range have been retreating since the 1850’s, the …

Experimental Determination Of Colburn And Friction Factors In Small Plate Heat Exchangers With High Surface Enlargement Factors, Andrew H. Pike

Masters Theses

Experiments were conducted to measure the performance of several small brazed plate heat exchangers. A test apparatus was designed and constructed that allowed for the easy switching of the plate heat exchangers, as well as having the ability to electronically monitor and record the inlet and outlet temperatures, pressures, and flow rates. The flow rates and applied electrical power were controlled electronically by the same program which recorded the data. De-ionized water was used as the heat transfer medium to reduce the uncertainty related to fluid properties.

An existing mathematical model was used to create Colburn and friction factors based …

Fatigue Behavior Of High-Entropy Alloys, Michael Alexander Hemphill

Masters Theses

Research was performed on the Al₉Co_18.2Cr_18.2Cu_18.2Fe_18.2Ni_18.2 [subscripts atomic percent] and Al_7.5Cr_22.5Fe₃₅Mn₂₀Ni₁₅ high-entropy alloys (HEAs) in an attempt to study their fatigue behavior. The present investigation shows encouraging fatigue-resistance characteristics due to their high fatigue lives of various samples at relatively high stresses. The current results indicate that the fatigue behavior of HEAs compares favorably to many conventional alloys, such as steels, titanium alloys, and advanced bulk metallic glasses with a fatigue-endurance limit of the Al₉Co_18.2Cr_{18.2 …}

The Implementation Of A Versatile Pseudodynamic Hybrid Simulation For Seismic Evaluation Of Structural Systems, Chelsea Griffith

Masters Theses

Pseudodynamic hybrid simulation technique was developed to evaluate structural seismic performance by physically testing the critical portion with the remaining structure simulated using a numerical model in the computer. An incremental approach was adopted in developing the control scheme to suit multiple testing facilities and test specimens. First the small scale, predictable specimen was utilized to investigate techniques of improving stability, slowing down the loading rate and triggering the accurate force measurement in a series of at benchmark scale experiments in the Laboratory of Earthquake and Structural Simulation at Western Michigan University (WMU). A step/hold command scheme was developed and …

High Capacity Lithium-Ion Battery Characterization For Vehicular Applications, Sazzad Hossain Ahmed

Masters Theses

A lithium-ion battery is one of the key research topics in energy storage technologies. Major characterization tests such as static capacity, open circuit voltage (OCV), hybrid pulse power characterization (HPPC) have been conducted on two different chemistries, LiMnNi and LiFePO₄, high capacity lithium-ion batteries over a wide range of temperatures from 50ºC to -30ºC. Detail analysis of temperature effects on battery capacity and simple models of direct current resistance (DCR) increment and power decrement over temperatures have been proposed using the test results. Electrochemical impedance spectroscopy (EIS) tests have been performed to find out the dominant internal resistances …

Power Transmission Line Fault Classification Using Support Vector Machines, Zhuokang Jia

Masters Theses

Electrical transmission lines are prone to faults and failures. When a fault occurs, it is impossible most of the times to fix it manually. Many methods have been adopted in the past in order to serve the purpose as fault diagnosing application. In this thesis, I discuss the method of Support Vector Machine (SVM) for fault diagnosis. SVM has the edge of good generalization over other fault diagnosing applications because it is based on pattern recognize algorithms. The aim is to classify the type of fault in the lines. Furthermore, in this work, the current and voltage of each phase …

Fabrication And Characterization Of Vertically Aligned Carbon Nanofibers (Vacnf) As Amperometric Biosensors On A Silicon-Compatible Platform, Kimberly Caitlin Macarthur

Masters Theses

This thesis presents fabrication, characterization and initial results of vertically aligned carbon nanofibers (VACNF)-based electrodes for use as electrochemical sensors. VACNFs are nanostructures that can be fabricated to the desired specifications using a plasma-enhanced chemical-vapor deposition process and are ideal candidates for electrode material because of their excellent electrical and structural properties. The first step of the fabrication of VACNFs on silicon substrates involved photolithography to pattern the interconnects and the catalysts (nickel dots). VACNFs were then grown on silicon substrates from the nickel catalysts, whose size determines the growth of a single nanofiber or a forest of nanofibers. This …

Fate And Transport Of 17beta-Estradiol Beneath Animal Waste Holding Ponds, Lori A. Gibson

Masters Theses

Steroidal hormones, such as 17beta-estradiol (E2) and its primary metabolite, estrone (E1), are prevalent in animal waste and are a common subject of study due to potential soil, stream, and groundwater contamination. These particular hormones are labeled as Endocrine Disrupting Chemicals (EDCs) because of their developmental effects in reptiles and amphibians. Dairy waste at concentrated animal feeding operations (CAFOs) is typically stored in a waste pond. Even though these waste ponds are regulated to include a soil liner with a minimal hydraulic conductivity to limit leaching, previous studies have traced stream and groundwater contamination from waste ponds. This research included …

Wireless Power Transfer System With Power Factor Correction For Electric Vehicles, Michael Christopher Pickelsimer

Masters Theses

Wireless power transfer is currently a popular topic of research. Because there are no mechanical connections between the transmitter and receiver, power can be transferred whenever a system is within range of a transmitter. Coil-to-coil efficiencies of over 95% at multiple kW have been recorded by researchers, proving that this type of charger has the potential to be a viable charging solution. Electric vehicles are a primary target for this technology because wireless power transfer systems may be able to provide power both while the vehicle is stationary or while in motion.

Despite the promises of high efficiency and high …

Track Prediction For Border Security Using A Discrete Kalman Filter, Jonathan William Hickerson

Masters Theses

Border security systems are a critical component in the prevention of the transnational trafficking of unlawful goods. For economic, environmental, and public safety related reasons, it is obviously desirable to prevent the transfer of materials such as illicit drugs, nuclear material, and unlawfully present individuals across borders; however, the deployment of trafficking countermeasures is a daunting task, wrought with unique challenges, such as unfamiliar terrain, long distances, and a potentially harsh environment.

The purpose of this thesis is to suggest a method to combine three different types of sensor systems to accurately track an individual as he crosses a field …

Two Studies On Controlling The Outflow From Sediment Basins: 1) Developing Discharge Coefficients For Circular Orifices In Round Riser Pipes, And 2) Optimizing The Solid State Skimmer, Alex James Mclemore

Masters Theses

Sediment pollution is a major contributor to stream and river impairment. Often, the source of sediment pollution is from a construction site’s runoff stormwater. A sediment retention basin, especially one with skimming outlet, can help minimize the sediment pollution from constructions sites. A sediment retention basin and outlet are specifically designed for each site to retain as much sediment as possible while satisfying other requirements such as peak flow rates and retention times. Because the modern designs needs have increased requirements, there is an increased need to be as accurate as possible when modeling the hydraulics and the sediment trapping …

Simulating The Effects Of Outer-Mold-Line Modification On The University Of Tennessee Space Institute's Aviation Systems' Piper Navajo Research Aircraft, Jonathan Vincent Kolwyck

Masters Theses

Aircraft used as research platforms often have their Outer-Mold-Lines (OML) modified to accommodate instrumentation packages associated with the research being performed. The external modification will change the aerodynamics of the aircraft, thus altering how the aircraft flies. The resulting performance, stability, and control of the aircraft can be effectively determined, but pilot opinion of aircraft handling qualities are largely unknown. The objective of this project is to be able to simulate aircraft flight control systems in the UTSI simulator, thus enabling the evaluation of pilot opinion of handling qualities. The design and implementation of a control loading system is described, …

Development And Use Of A Simple Test Method To Evaluate Reheat Cracking Sensitivity In The Weld Deposit Region Of A Submerged Arc Weld, Maxwell Calder Trent

Masters Theses

Several fabricators have recently noted the occurrence of reheat cracking in the weld deposits of 2¼[ two and one fourth]Cr‑1Mo‑¼[one fourth]V (22V) during the fabrication of pressure vessels used in the petrochemical industry. Due to increased oversight now required during fabrication of already expensive pressure vessels, studies have commenced worldwide in an effort to identify root causes and formulate mitigating actions to weld reheat cracking issues. The Materials Joining Group (MJG) at the University of Tennessee at Knoxville (UTK) have adapted an existing reheat cracking test originally developed for use with alloys similar to 22V. This original C‑Ring test was …

A Memory Controller For Fpga Applications, Bryan Jacob Hunter

Masters Theses

As designers and researchers strive to achieve higher performance, field-programmable gate arrays (FPGAs) become an increasingly attractive solution. As coprocessors, FPGAs can provide application specific acceleration that cannot be matched by modern processors. Most of these applications will make use of large data sets, so achieving acceleration will require a capable interface to this data. The research in this thesis describes the design of a memory controller that is both efficient and flexible for FPGA applications requiring floating point operations. In particular, the benefits of certain design choices are explored, including: scalability, memory caching, and configurable precision. Results are given …

Analog Testing, Characterization, And Low-Order Model Extraction Using Labview Automation, Jeremy Brantley

Masters Theses

Testing circuits is a hands-on, time intensive process; it is also one of the most important steps in a design cycle. The most well designed circuit is only an academic exercise if it does not work in real life. The time and cost associated with bench level testing pales in comparison to testing for extreme environments. Testing in extreme heat, cold or radiation introduces a large set of challenges that are rarely encountered in standard bench level testing. The two most pronounced problems are the inaccessibility of the devices under test and time constraints, both short and protracted. Due to …

Pretreatment And Pyrolysis Of Rayon-Based Precursor For Carbon Fibers, Kokouvi Akato

Masters Theses

In this work, two rayon fibers were investigated as carbon fiber precursors. A detailed consideration has been applied to a domestically produced cellulose fiber to carbon fiber (CF) transition. This transition of precursor to carbon fiber can be subdivided into two stages: pyrolysis (thermal decomposition) of cellulose in air and high temperature treatment in an inert atmosphere. The specific objectives were to investigate the stabilization stage of the produced rayon with respect to changes taking place during thermal decomposition, and to evaluate the effects on the properties of the carbonized fiber. Changes taking place during the conversion process of the …