Open Access. Powered by Scholars. Published by Universities.®

Mechanical Engineering Commons

Open Access. Powered by Scholars. Published by Universities.®

University of Tennessee, Knoxville

2016

Discipline
Keyword
Publication
Publication Type

Articles 1 - 25 of 25

Full-Text Articles in Mechanical Engineering

Impedance-Resolved Performance And Durability In Redox Flow Batteries, Alan Michael Pezeshki Dec 2016

Impedance-Resolved Performance And Durability In Redox Flow Batteries, Alan Michael Pezeshki

Doctoral Dissertations

The realization of redox flow batteries (RFBs) as a grid-scale energy solution depends on improving the performance and lifetime of the technology to decrease the high capital costs. The electrodes are a key component in the RFB; performance enhancement is often achieved through chemical or thermal treatments of commercially available porous carbon materials.

This dissertation uses impedance spectroscopy-based methods to gain insight into performance and durability in RFBs, enabling intelligent cell design. Initial work focused on understanding the impact of improved electrode and membrane properties on system performance. An accelerated stress test was then developed that can be used to ...


Investigation Of Localized Performance And Gas Evolution In All-Vanadium Redox Flow Batteries Via In-Situ Distributed Diagnostic Techniques, Jason Thomas Clement Dec 2016

Investigation Of Localized Performance And Gas Evolution In All-Vanadium Redox Flow Batteries Via In-Situ Distributed Diagnostic Techniques, Jason Thomas Clement

Doctoral Dissertations

All-vanadium redox flow batteries (VRFBs) are an emerging grid-scale energy storage technology; however, enhancements in terms of performance, efficiency, durability, and cost are required before it can become commercially viable. These improvements are achievable through the development of advanced materials, superior architecture, and ultimately a deeper fundamental understanding of the influence of various phenomena and operational parameters on cell performance. There currently are a lack of in-situ experimental diagnostic techniques which can help in achieving this fundamental understanding.

Two separate distributed diagnostic techniques were developed in this work: in-plane current distribution, and neutron radiography. Localized current distribution measurements can identify ...


Parametric Instability And Vibration Suppression Of Planetary Gear Transmissions Supported On Boundary Struts, Peng Guan Dec 2016

Parametric Instability And Vibration Suppression Of Planetary Gear Transmissions Supported On Boundary Struts, Peng Guan

Doctoral Dissertations

This dissertation explores the effects of discrete boundary strut properties on stability and vibration of the planetary gear transmission (PGT) driveline systems. Also, a robust output feedback control law is developed to actively control the PGT system vibrations. To better obtain boundary strut properties, a light-weight boundary strut design was developed for two popular boundary strut configurations by considering yield stress, buckling, and local buckling constraints. To facilitate analysis and development of the active control law, a comprehensive analytical PGT driveline system with elastic ring model, including gyroscopic effect and rotating-frame damping, is developed. The equation of motion of the ...


Deterministic Neutron Transport And Multiphysics Experimental Safety Analyses At The High Flux Isotope Reactor, Christopher James Hurt Dec 2016

Deterministic Neutron Transport And Multiphysics Experimental Safety Analyses At The High Flux Isotope Reactor, Christopher James Hurt

Doctoral Dissertations

The computational ability to accurately predict the conditions in an experiment under irradiation is a valuable tool in the operation of a research reactor whose scientific mission includes isotope production, materials irradiation, and neutron activation analysis. Understanding of different governing physics is required to ascertain satisfactory conditions within the experiment: the neutron transport behavior throughout the reactor and the coupled behavior of heat transfer, structural mechanics and fluid flow. Computational methods and tools were developed for robust numerical analysis of experiment behavior at the Oak Ridge National Laboratory (ORNL) High Flux Isotope Reactor (HFIR), including fully-coupled thermo-mechanics in three plutonium-238 ...


Development, Analysis, And Optimization Of A Swirl-Promoting Mean Flow Solution For Solid Rocket Motors, Andrew Steven Fist Dec 2016

Development, Analysis, And Optimization Of A Swirl-Promoting Mean Flow Solution For Solid Rocket Motors, Andrew Steven Fist

Masters Theses

This work demonstrates and analyses a new flow candidate for describing the internal gaseous motion in simulated rocket motors. The fundamental features of this solution include the conservation of key system properties also incorporated in the classic Taylor-Culick (TC) system (i.e. inviscid, axisymmetric, steady and rotational properties), while allowing for the development of a swirling velocity component. The work compares the new solution to the development and formulation of the classic TC system, ultimately identifying that both the new and classic solutions are special cases of the Bragg-Hawthorne equation. Following this development, the text then explores the development of ...


Fundamental Studies Of Electrochemical Reactions And Microfluidics In Proton Exchange Membrane Electrolyzer Cells, Jingke Mo Dec 2016

Fundamental Studies Of Electrochemical Reactions And Microfluidics In Proton Exchange Membrane Electrolyzer Cells, Jingke Mo

Doctoral Dissertations

In electrochemical energy devices, including fuel cells, electrolyzers and batteries, the electrochemical reactions occur only on triple phase boundaries (TPBs). The boundaries provide the conductors for electros and protons, the catalysts for electrochemical reactions and the effective pathways for transport of reactants and products. The interfaces have a critical impact on the overall performance and cost of the devices in which they are incorporated, and therefore could be a key feature to optimize in order to turn a prototype into a commercially viable product. For electrolysis of water, proton exchange membrane electrolyzer cells (PEMECs) have several advantages compared to other ...


Turbine Engine Rotor Blade Damage Detection Through The Analysis Of Vibration Of Stationary Components, Jon Rylan Cox Dec 2016

Turbine Engine Rotor Blade Damage Detection Through The Analysis Of Vibration Of Stationary Components, Jon Rylan Cox

Doctoral Dissertations

Rotor blade fault detection and health monitoring systems are crucial for gas turbine engine testing and evaluation. The most commonly used techniques involve monitoring blades directly using strain gages, or drilling optical access holes in the engine casing for non-contact probes to monitor blade deflection and vibration. In this work, less intrusive, indirect techniques for rotor blade fault detection are developed, based on the hypotheses that the vibratory response of stationary components excited by the rotor blade dynamic pressure pulse can be used to detect the presence, location, and severity of rotor blade damage and changes in rotor blade natural ...


Effects Of Ultrasonic Transducers On Heat Transfer In Packed Particle Beds, David Patrick Moseley Dec 2016

Effects Of Ultrasonic Transducers On Heat Transfer In Packed Particle Beds, David Patrick Moseley

Masters Theses

The objective of this study was to determine the effects of ultrasonic transducers on heat transfer in a packed particle bed heat exchanger. Although substantial research has been devoted to ultrasound, and the associated improvements in heat transfer, data regarding the effects on packed particle beds is non-existent. This is of particular interest given the potential to improve heat transfer in a wide variety of packed particle bed systems. A 42.9% increase in the heat transfer rate was demonstrated as the result of improved fluid convection throughout the packed particle bed. Secondary effects, including acoustic cavitation, acoustic streaming and ...


Tracking Of Human Joints Using Twist And Exponential Map, Xiaodong Yang Dec 2016

Tracking Of Human Joints Using Twist And Exponential Map, Xiaodong Yang

Masters Theses

Motion tracking system in the home-based environment exhibits attractive advantages for stroke patients. Current methods suffer from incapability of accurately tracking movements with high degree of freedoms. Besides hardly meeting the predefined position during inertial sensor mounting also affects system's performance.

To tackle these challenges, a motion tracking system using twist and exponential map technology is developed in this paper. Firstly, a kinematic model for trunk and upper extremity is designed. Based on this model, twist and exponential map method which updates frames in their initial coordinates instead of transforming coordinates from one frame to another presents high efficiency ...


Dynamic Monitoring And Life Prediction Of Internal Strain-Gage Balances, David Leon Yoder Dec 2016

Dynamic Monitoring And Life Prediction Of Internal Strain-Gage Balances, David Leon Yoder

Masters Theses

Wind tunnel test customers continue to push the limits by producing air vehicle designs that produce high aerodynamic loads at the desired test conditions. These loads are a combination of steady aerodynamic, unsteady aerodynamic, and inertial forces. A methodology to monitor the health of a wind tunnel strain-gage balance has been developed. The objective of this methodology is to define the stress limits of the balance and monitor these limits so the balance can be safely tested without failure of the balance. A balance failure could result in costly damage to the wind tunnel model, support system, and the wind ...


Lattice Boltzmann Methods For Wind Energy Analysis, Stephen Lloyd Wood Aug 2016

Lattice Boltzmann Methods For Wind Energy Analysis, Stephen Lloyd Wood

Doctoral Dissertations

An estimate of the United States wind potential conducted in 2011 found that the energy available at an altitude of 80 meters is approximately triple the wind energy available 50 meters above ground. In 2012, 43% of all new electricity generation installed in the U.S. (13.1 GW) came from wind power. The majority of this power, 79%, comes from large utility scale turbines that are being manufactured at unprecedented sizes. Existing wind plants operate with a capacity factor of only approximately 30%. Measurements have shown that the turbulent wake of a turbine persists for many rotor diameters, inducing ...


Developing Predictive Models For Upper Extremity Post–Stroke Motion Quality Estimation Using Decision Trees And Bagging Forest, Sarvenaz Chaeibakhsh Aug 2016

Developing Predictive Models For Upper Extremity Post–Stroke Motion Quality Estimation Using Decision Trees And Bagging Forest, Sarvenaz Chaeibakhsh

Masters Theses

Stroke is one of the leading causes of long–term disability. Approximately twothirds of stroke survivors require long-term rehabilitation, which suggests the importance of understanding the post-stroke recovery process during his activities of daily living. This problem is formulated as quantifying and estimating the poststroke movement quality in real world settings. To address this need, we have developed an approach that quantifies physical activities and can evaluate the performance quality. Wearable accelerometer and gyroscope are used to measure the upper extremity motions and to develop a mathematical framework to objectively relates sensors’ data to clinical performance indices. In this article ...


Laser Diagnostics Of C2h4 And Ch4 From N-Butane Pyrolysis, Liu Su Aug 2016

Laser Diagnostics Of C2h4 And Ch4 From N-Butane Pyrolysis, Liu Su

Masters Theses

Combustion of fossil fuels remains the dominant source of energy which enables us sustain thrive in this planet. Meanwhile, the negative effects of burning fossil fuels, however, are devastating our climate and environment. Eliminating those negative effects while attaining energy supply from fossil fuels becomes urgent and prominent. It is, nevertheless, impossible without a thorough understanding of the combustion process.

Experimental approach remains one of the dominating approaches to study combustion despite the growing interest in numerical approach. The development of workstations and massive supercomputers is providing the computation ability that one has never imaged. Nevertheless, it still appears difficult ...


Study To Reduce Peak Electrical Demand Charges For The John C. Hodges Library, Jared Thomas Carpenter, Isaac Michael Robinette, Matthew Joeseph Conrad, Daniel Matthew Whaley, William A. Miller May 2016

Study To Reduce Peak Electrical Demand Charges For The John C. Hodges Library, Jared Thomas Carpenter, Isaac Michael Robinette, Matthew Joeseph Conrad, Daniel Matthew Whaley, William A. Miller

Chancellor’s Honors Program Projects

No abstract provided.


Automated Fusegrade Testing Machine, Natalie A. Rayfield, Peter Trzil, Dylan Moore, Colin Roberson, Haley Register May 2016

Automated Fusegrade Testing Machine, Natalie A. Rayfield, Peter Trzil, Dylan Moore, Colin Roberson, Haley Register

Chancellor’s Honors Program Projects

No abstract provided.


Senior Design Project, Lee F. Collier 7737457, Amy Albaugh, Jacob Walker, Justin Church May 2016

Senior Design Project, Lee F. Collier 7737457, Amy Albaugh, Jacob Walker, Justin Church

Chancellor’s Honors Program Projects

No abstract provided.


Adaptive Kernel Estimation For Enhanced Filtering And Pattern Classification Of Magnetic Resonance Imaging: Novel Techniques For Evaluating The Biomechanics And Pathologic Conditions Of The Lumbar Spine, Nicholas Vincent Battaglia May 2016

Adaptive Kernel Estimation For Enhanced Filtering And Pattern Classification Of Magnetic Resonance Imaging: Novel Techniques For Evaluating The Biomechanics And Pathologic Conditions Of The Lumbar Spine, Nicholas Vincent Battaglia

Doctoral Dissertations

This dissertation investigates the contribution the lumbar spine musculature has on etiological and pathogenic characteristics of low back pain and lumbar spondylosis. This endeavor necessarily required a two-step process: 1) design of an accurate post-processing method for extracting relevant information via magnetic resonance images and 2) determine pathological trends by elucidating high-dimensional datasets through multivariate pattern classification. The lumbar musculature was initially evaluated by post-processing and segmentation of magnetic resonance (MR) images of the lumbar spine, which characteristically suffer from nonlinear corruption of the signal intensity. This so called intensity inhomogeneity degrades the efficacy of traditional intensity-based segmentation algorithms. Proposed ...


Investigation Of Langmuir Probes In Non-Maxwellian Plasma Using Particle-In-Cell (Pic) Modeling, Densu Aktas Lister May 2016

Investigation Of Langmuir Probes In Non-Maxwellian Plasma Using Particle-In-Cell (Pic) Modeling, Densu Aktas Lister

Doctoral Dissertations

This dissertation explores the development of a capability for simulating the plasma dynamics of Langmuir probes (LP) in complex plasmas where the velocity distributions are non-equilibrium and the electron energy spectrum is non-Maxwellian with respect to laboratory and space experiments. The results of this investigation are interpreted to give recommendations for design and use of LPs. This work is conducted using computational techniques to create the exact plasma conditions of the experimental testing environments. The investigations address the following topics:

  • development of a technique to model non-Maxwellian physics,
  • modification of a baseline-technique and optimization of it for this application,
  • creation ...


Inter-Droplet Membranes For Mechanical Sensing Applications, Nima Tamaddoni Jahromi May 2016

Inter-Droplet Membranes For Mechanical Sensing Applications, Nima Tamaddoni Jahromi

Doctoral Dissertations

This dissertation combines self-assembly phenomena of amphiphilic molecules with soft materials to create and characterize mechanoelectrical transducers and sensors whose sensing elements are thin-film bioinspired membranes comprised of phospholipids or amphiphilic polymers. We show that the structures of these amphiphilic molecules tune the mechanical and electrical properties of these membranes. We show that these properties affect the mechanoelectrical sensing characteristic and range of operation of these membrane transducers. In the experiments, we construct and characterize a membrane-based hair cell embodiment that enables the membrane to be responsive to mechanical perturbations of the hair. The resulting oscillations of membranes formed between ...


Tribological Testing And Analysis Of Ionic Liquids As Candidate Anti-Wear Additives For Next-Generation Engine Lubricants, William Charles Barnhill May 2016

Tribological Testing And Analysis Of Ionic Liquids As Candidate Anti-Wear Additives For Next-Generation Engine Lubricants, William Charles Barnhill

Masters Theses

In this work, fourteen ionic liquids (ILs) were assayed as potential next-generation engine oil additives. After screening for corrosion, thermal stability and oil solubility, candidate additives were subjected to friction and wear tests in both boundary and mixed regime lubrication. While each IL demonstrated friction and wear reduction compared to base oil without any additives, oil miscible ILs tetraoctylphosphonium bis 2-ethylhexyl phosphate ([P8888][DEHP]) and trioctylammonium bis 2-ethylhexylphosphate ([N888H][DEHP]) were the best performers in bench tests with a XX% and XX% improvement in wear over the base oil respectively. Each of these ILs excellent solubility and superior performance was ...


Measurement Of Water Ice Accumulation On A First Surface Gold Mirror Under Cryogenic, High-Vacuum Conditions, William Hayden Stevens May 2016

Measurement Of Water Ice Accumulation On A First Surface Gold Mirror Under Cryogenic, High-Vacuum Conditions, William Hayden Stevens

Masters Theses

Spacecraft optical components must be tested in vacuum chambers in order to achieve “space-like” conditions on earth. To simulate the low temperatures experienced in space, optical components are often cryogenically cooled in the vacuum chamber. Outgassing of contaminants, such as water molecules, from the metal walls of the vacuum chamber occur under high vacuum conditions. These free water molecules accumulate and freeze on the cryogenic optical surfaces, which affects performance and reflectivity.

A multiple beam interference set-up was used to measure the accumulation of a water ice film on a first surface gold mirror under cryogenic, high vacuum-conditions. Zeolite molecular ...


Improving Ventricular Catheter Design Through Computational Fluid Dynamics, Sofy Hefets Weisenberg May 2016

Improving Ventricular Catheter Design Through Computational Fluid Dynamics, Sofy Hefets Weisenberg

Masters Theses

Cerebrospinal fluid (CSF) shunts are fully implantable medical devices that are used to treat patients suffering from conditions characterized by elevated intracranial pressure, such as hydrocephalus. In cases of shunt failure or malfunction, patients are often required to endure one or more revision surgeries to replace all or part of the shunt. One of the primary causes of CSF shunt failure is obstruction of the ventricular catheter, a component of the shunt system implanted directly into the brain's ventricular system. This work aims to improve the design of ventricular catheters in order to reduce the incidence of catheter obstruction ...


Improved Modeling Of Atmospheric Entry For Meteors With Nose Radii Between 5cm And 10m, Jakob Dale Brisby May 2016

Improved Modeling Of Atmospheric Entry For Meteors With Nose Radii Between 5cm And 10m, Jakob Dale Brisby

Masters Theses

Atmospheric entry studies typically look closely at the peak heating rate that a body encounters during its trajectory. This is an extremely important phenomenon to study because it allows engineers to determine if a trajectory is possible with given materials and craft design specifications. It also allows designers to choose what type of method will be used for mitigating the enormous heat fluxes during entry. In general, it is accepted that during the super-sonic flight regime the body will continue to be heated and an ablative heat shield often is used to deal with these heating processes. The theory outlined ...


Jet Flow Validation Of Positron Emission Particle Tracking Utilizing High Speed Video, Seth Thomas Langford May 2016

Jet Flow Validation Of Positron Emission Particle Tracking Utilizing High Speed Video, Seth Thomas Langford

Masters Theses

Positron Emission Particle Tracking (PEPT) generates 4D Lagrangian particle trajectories and is used to evaluate flow in granular media and complex geometries where optical interrogation methods are not possible. A Multi-Particle PEPT (Multi-PEPT) approach was developed by the University of Tennessee Thermal Fluids Group capable of finding and tracking many particles simultaneously to extend the utility of the PEPT method. This thesis compares 4,014 trajectories generated using the Multi-PEPT method with 3,055 trajectories generated from High Speed Video (HSV) data. All trajectories are acquired in an acrylic test section with water flow using resin beads. The flow geometry ...


Squeaver, Cole Stonebrook, Matthew Frana, Samuel Tabor Apr 2016

Squeaver, Cole Stonebrook, Matthew Frana, Samuel Tabor

EURēCA: Exhibition of Undergraduate Research and Creative Achievement

Overhanging limbs pose a threat to many homeowners with trees in their yard. If these limbs fall, property damage and personal injury are a major possibility. Currently the two methods used to cut and remove these limbs are hiring a tree service to use a boom truck to lift an arborist up to the limb or having a tree climber cut and lower the limb. Both methods are unsafe and expensive. Our design will be a tree-trimming device that can be rented from an equipment rental facility and operated by the homeowner. The machine will have the capability to extend ...