Mechanical Engineering Commons^™

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 local …

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 …

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 and …

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 energy-optimized …

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 we …

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 …

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

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 includes a …

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

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 and …

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 attributed to …