Engineering Commons^™

Global Skin Friction Diagnostics In Complex Separated Flows, Sudesh A. Woodiga

Masters Theses

This work describes the application of a global luminescent oil film skin friction meter to quantitative global skin friction diagnostics in complex separated flows. The development of this technique is based on the relationship between the oil film thickness and luminescent intensity of an oil film mixed with a luminescent dye. The projected thin oil film equation is given to relate the normalized luminescent intensity with skin friction. The basis for this technique is the variational solution for the thin oil film equation on the image plane. The variational formulation with a smoothness constraint on skin friction is proposed to …

Analysis Of Cavity Flow And The Effects Of A Rod In Crossflow, Richard David Loewen

Masters Theses

Subsonic cavity flow tests of an L/D = 3.5 cavity, with three different diameter rods in crossflow, 1/8", 3/16", and 1/4", were conducted using the High Speed Wind Tunnel in the University of Tennessee Space Institute’s Gas Dynamic Laboratory. The average Mach number flow over the duration of the four phase testing sequence was 0.52, with a unit Reynolds number of 13.8 x 106. With the use of a dynamic pressure transducer and a laser PIV system, Spectral and Flow Visualization data was collected with aim of investigating the effect of the rods in crossflow on cavity flow. However, for …

New Consolidation Of Emission And Processing For Air Quality Modeling Assessment In Asia, Yuan Du

Masters Theses

Gridded Asian emission input with fine resolutions for regional photochemical air quality modeling is absent from current studies. A new top-down emission process based on GIS-FORTRAN program has been developed in this study to consolidate the current available regional emissions in Asia and provide model-ready emission input with more flexibility. The INTEX-B anthropogenic emission inventory in 2006 integrated with biogenic from GEIA, as well as biomass burning and ship emissions from TRACE-P has been adopted as the top-level emissions, which are then spatially allocated into grid-cell level by our GIS application. The spatial allocation factors generated for this process are …

Multi-Channel Real-Time Communication In Wireless Sensor Network, Nitish Kumar Jha

Masters Theses

Many radio chips used in today's sensor mote hardware can work at different frequencies. Recently, several multi-channel communication protocols have been proposed to improve network throughput and reduce packet loss for wireless sensor networks. However, existing work does not provide explicit guarantees for application-specified end-to-end communication delays, which are critical to many real-time applications such as surveillance and disaster response. On the other hand, those radio chips also have adaptable transmission power which allows a trade-off between communication delays and energy efficiency.

This work proposes two multi-channel real-time communication protocols. One of the protocols features a node-based channel assignment policy …

A Systems Approach To Selecting And Outfitting A Helicopter For Airborne Law Enforcement, Francesco J. Lombardi

Masters Theses

A modern day airborne law enforcement helicopter is an exercise in compromise. Applying a Systems Engineering approach to selecting and outfitting a helicopter for airborne law enforcement can bring order to the process. The Suffolk County Police Aviation Section of New York was used as an example agency profile in analyzing mission requirements, establishing constraints, and analyzing alternatives. A benchmark survey was established for use in comparison.

Benchmark trends indicated power margin and useful load as the primary performance requirements of an airborne platform with a primary mission of Emergency Medical Service (EMS) and a secondary mission of patrol. EMS …

Fault Current Limiting And Protection Circuit For Power Electronics Used In A Modular Converter, Shibani Mishra

Masters Theses

The thesis objective is to safeguard power electronics used in modular converter applications. A new fault current limiting and protection circuit is proposed. The system level fault mitigation assemblies take a long time to remove a fault and within this time the IGBTs used in the Flexible AC Transmission System (FACTS) application will undergo high thermal and mechanical stress. Exposure to such conditions over a prolonged period of time will reduce the device lifetime, which is one of the major reasons why power electronics are not very popular in utility applications. Modular converter approach will reduce the device ratings required …

Laser Processing Of Refractory Metal - Refractory Carbide Alloys, Deepak Rajput

Masters Theses

The objective of the present study was to laser process a refractory metal – refractory carbide alloy based on W-Ti-C ternary system for severe service applications. The key concept was to cast a eutectic alloy of tungsten and titanium carbide/carbonitride straight from the melt through laser materials processing route. In the present study, a WTi- C ternary alloy has been laser processed into three-dimensional objects and surface protective coatings. Two novel fabrication systems were designed to build threedimensional objects, namely tower nozzle solid freeform fabrication system and axissymmetric laser powder deposition system. W-Ti-C alloy based protective coatings were deposited on …

Synergistic Effect Of Retinoic Acid, Nerve Growth Factor And Laminin For Enhanced Neurite Extension, Shrarath Ashwin Sriman

Masters Theses

Peripheral Nerve Injury is one of the most common and serious traumatic injuries. About 300,000 cases of peripheral nerve injury are reported annually in Europe and another 50,000 procedures performed annually in the United States. Peripheral nerve injury can lead to lifelong disability and also death in severe cases. Repair techniques remain a major challenge because of lack of efficient regeneration. Though techniques like autografts are highly efficient, they face a lot of drawbacks. Alternate methods focus on the use of growth supporting and enhancement components in nerve guidance channels. Current research necessitates the use of a combination of compounds …

Preliminary Design, Flight Simulation, And Task Evaluation Of A Mars Airplane, Dodi Deanne Walker

Masters Theses

A limited aerodynamic, stability and control, and task evaluation of a new rocket-powered Mars airplane design was conducted. The Mars airplane design, designated the Argo VII, was patterned after the NASA ARES-2 design. The aerodynamic and stability and control parameters of the Argo VII were determined using analytical and computational techniques and were comparable to those of the ARES-2. The Argo VII was predicted to be statically stable and damped in all axes on Earth and Mars. A series of flight tests were performed using a MATLAB Simulink-based flight simulation program to assess the performance, longitudinal flying qualities, and mission …

Liquid Viscosity Measurement Technique Using Space Microgravity Environment, Nobuhisa Yasuda

Masters Theses

The purpose of this research is to validate a method of determining viscosity of highly viscous liquids with known surface tension in which is not confined by solid wall.

The major part of the work involves comparing and analyzing the data from the Fluid Merging Viscosity Measurement experiments (FMVM), conducted onboard the ISS, with results from numerical analysis codes. In these experiments, two different size or equal size droplets are deployed and allowed to merge under the action of the known surface tension without any external forcing. The drop merging process is performed in the zero gravity environment of space …

The Effect Of Distributed Generation On Distribution System Reliability, Nura Nubee Sabir

Masters Theses

Electricity produced and delivered to customers constitutes one of the largest consumer markets in the world. As a nation we have become so dependent that most daily functions would be suspended if there were any interruption in power generation, transmission and distribution. Historically there has been a great deal of effort put into modeling and improving the reliability of the generation and transmission systems. However, when compared to the generation and transmission systems, considerable less resources has been placed on the details of making the distribution system more reliable. Majority of all interruptions experienced by the customer in a given …

A Flight Test Study To Assess The Utility Of An Aircraft Referenced 3d Audio Display To Improve Pilot Performance Under High Workload Conditions, Mehendi Hassan Naqvi

Masters Theses

A study to assess the utility of an aircraft referenced 3D audio display was undertaken to determine if there could be any improvements to pilot performance when operating under high workload conditions. Test subjects flew a general aviation light twin-engine aircraft under simulated single-pilot instrument flight rule conditions. Workload was elevated by ensuring each test subject had to execute an unexpected missed approach procedure and simultaneously handle a simulated engine failure. Subjective data was gathered using the NASA Task Load Index and a post-flight questionnaire on perceived performance, workload and situational awareness. Objective data on pilot performance was gathered using …

Resonant Ultrasound Studies Of Quasi-2d NaXCoo2, Timothy Allen Cagle

Masters Theses

Sodium cobaltate possesses all the important traits needed in a material for potential thermoelectric applications yet it shows little regard for the traditional physics of thermoelectrics. As existing theories regarding the phenomenon in Na_xCoO₂ are incomplete, we have set out to elucidate some of the issues by looking into the elastic response of the system. To this effect, we have employed Resonant Ultrasound Spectroscopy to obtain the elastic tensor at various temperatures. As the Na_0.75CoO₂ stoichiometry seemed to potentially offer the most rewards due to a pronounced ground state and anomalous thermopower at higher …

Removing Acetic Acid From The Urex+ Process, Jessica Anne Mitchell

Masters Theses

Acetic acid needs to be removed from a waste stream in the UREX+ process so that nitric acid can be recycled and possible interference with downstream steps can be avoided. Acetic acid arises from acetohydroxamic acid (AHA) used to suppress plutonium in the first step of the UREX+ process. Later, it is hydrolyzed into hydroxyl amine nitrate and acetic acid. Many common separation technologies were examined, and solvent extraction was determined to be the best choice under process conditions. Solvents already used in the UREX+ process were then tested to determine if they would be sufficient for the removal of …

Generation And Analysis Of Fcg Data Using A Single Specimen And Kmax - ∆K Testing Matrix, Sree Phani Chandar Reddy

Masters Theses

A custom method to generate fatigue crack growth (FCG) data requires testing of multiple specimens at different load ratios. In addition, it includes the application of a load shedding procedure from pre-cracking level to threshold.

In this thesis, a novel method of testing has been investigated that utilizes a single specimen and a testing matrix in terms of K_maxand ∆K values corresponding to predetermined R-ratios for which FCG data, da/dN, are recorded. Automatic K-controlled tests on 2324-T39 Al alloy were conducted using the ∆K increasing and ∆K decreasing procedures while K_maxwas kept constant. Results show that …

Moisture Degradation Of Ctd-403: Testing The Application Of Cyanate Ester Insulations To Fusion Devices, Bradley Ian Morgan

Masters Theses

The fusion devices currently being developed present several challenges for magnet designers. One challenge lies within the electrical insulation, which must be able to withstand extreme temperatures (both cryogenic and elevated temperatures), large shear and compressive stresses, high operating voltages, and high levels of incident radiation. To address the need for better performing insulation systems, Composite Technology Development, Inc. (CTD) has developed CTD-403, a cyanate ester resin with increased radiation resistance, ease of processing and fabrication, low moisture absorption characteristics, and high mechanical and electrical strength at cryogenic and elevated temperatures.

In this thesis, CTD-403 resin based insulation systems were …

Accelerated Thermal Aging Of Fe-Zeolite Scr Catalysts On An Engine Bench, Adam Lamar Foster

Masters Theses

Selective catalytic reduction (SCR) of NO_x with urea/NH₃ is a leading candidate to the impending more stringent emissions regulations for diesel engines. Currently, there is no consensus on the durability and the deactivation mechanisms associated with zeolite-based SCR catalysts, nor is there an established protocol for rapidly aging zeolite-based SCR catalysts that replicates the catalyst deactivation associated with field service. A 517 cc single-cylinder, naturally-aspirated direct injection (NA/DI) diesel engine is used to perform accelerated thermal aging on Fe-zeolite SCR catalysts. The engine is fitted with an exhaust aftertreatment system consisting of a DOC, a SCR catalyst and …

The Influence Of Hydrological Patterns On Brook Trout (Salvelinus Fontinalis) And Rainbow Trout (Oncorhynchus Mykiss) Population Dynamics In The Great Smoky Mountains National Park., Joesph Michael Parker

Masters Theses

Hydrologic processes impact the functioning of aquatic ecosystems and influence fish population dynamics. The flow regime of a stream affects the structure, composition, and productivity of fish communities by regulating abiotic habitat conditions and biotic community processes. In the Great Smoky Mountains National Park (GRSM), native brook trout (Salvelinus fontinalis) populations have declined in some watersheds over the past decade, believed to be primarily due to episodic acidification. The potential affects long-term hydrologic patterns, temporal hydrologic trends, and hydrologic extremes have on brook and rainbow trout (Oncorhynchus mykiss) populations were explored in this study. The current …

Numerical Analysis For Determination Of Fiber Orientation In Nonwoven Mats, Lee Reynolds Allen

Masters Theses

The University of Tennessee Space Institute is interested in pitch-based carbon fibers. A need has arisen for characterizing relative alignment of nonwoven fiber mats, produced by the spinning gathering technology implemented. Knowledge of this alignment is relevant in the validation of production methodology as well as aiding in the analysis of carbon fiber composite materials made with the fiber mats. A digital image processing method was developed presented and evaluated in this thesis consisting of three steps: preprocessing using image smoothing, edge detection based upon local intensity gradients, and line detection via the Hough Transform. A summary of typical results …

Simulating Truck Lane Management Approaches To Improve Efficiency And Safety Of Highways In Knoxville, Tennessee, Adebola Adebisi Adelakum

Masters Theses

Increased globalization has caused large increases in truck traffic on the nation’s interstate system, with much additional growth expected in the coming years. This growth has elevated interest in developing new strategies to address rising levels of truck traffic, especially in dense and congested urban areas. This thesis focuses on the evaluation of several alternative lane management configurations as they compare to the current lane configuration in search of the best fit for operational improvement. This task was performed in two ways – survey and simulation. A survey of 500 long-haul truck drivers was administered in Knoxville, Tennessee, at the …

The Application Of A Two-Dimensional Sediment Transport Model In A Cumberland Plateau Mountainous Stream Reach With Complex Morphology And Coarse Substrate, Daniel Hale Johnson

Masters Theses

Among river engineers there is growing recognition that the success of a stream restoration project is dependent on the accurate prediction of sediment transport along a reach. To aid the design process, several numerical one- and multi-dimensional models have been developed to quantify in-stream sediment transport and hydraulic characteristics, and multiple sampling techniques have been proposed to establish the upstream sediment supply. However, the governing physical boundaries and variables (i.e., Manning’s ‘n’ variable, energy slope, and upstream sediment supply) required to initiate a sediment transport simulation are time consuming and difficult to measure in the field, and the estimation of …

Design And Development Of An Apd Algorithm Development Board For Positron Emission Tomography, Rakesh Mallem

Masters Theses

Using the PET scanner, three dimensional images of the human body with sufficient detail can be viewed which help physicians to visualize both normal metabolic functions and discover the chemical processes underlying physical abnormalities. Commercial PET scanners employ Photo Multiplier Tubes to detect the anti-matter annihilation photons and amplify the signals to a suitable level for digital sampling. Photomultiplier tubes provide extremely high sensitivity and exceptionally low noise compared to other photosensitive devices currently used to detect radiant energy in the ultraviolet, visible and near infrared regions. A combined magnetic resonance positron emission tomography (MR-PET) modality would require a solid-state …

A High Voltage Ccd Sensor Control Chip For The Large Synoptic Survey Telescope (Lsst), Zuoliang Ning

Masters Theses

This thesis presents the design of a Sensor Control Chip (SCC) developed to provide the required clock and bias signals for the Large Synoptic Survey Telescope’s CCD imagers. The circuit consists of current-summing DACs followed by trans-impedance operational amplifiers to control the rail voltages of the clock signals and bias voltages. The clocks are input to the SCC through LVDS receivers and converted internally to the required amplitude for driving the CCDs. The ASIC is designed to drive clock signals with 20-V adjustable output voltage swing and a maximum output current of 150 mA. The prototype chip has been fabricated …

Optimizing The Use Of The United States Army Oh-58d Helicopter Simulator And Aircraft For Full-Authority Digital Electronic Control Manual Throttle Training, Conrad Rodgers

Masters Theses

Over the past decade the United States Army has used a Full-Authority Digital Electronic Control (FADEC) system to control fuel flow to the engine of the OH-58D helicopter. Currently, part of the training is primarily conducted for the scenario of a FADEC system failure in the aircraft. Because of the complexity of this task, a number of accidents have occurred resulting in minor to severe damage to the aircraft. The United States Army has recently fielded two OH-58D Operational Flight Training Simulators in an effort to increase training efficiency and effectiveness. It is anticipated that the simulators will provide a …

Design Of A Low-Power Precision Op Amp With Ping-Pong Autozero Architecture, Pengfei Xi

Masters Theses

Precision op amps are widely used in instrumentation, automotive, and industrial applications. This thesis presents the design and characterization of a low-power precision operational amplifier that uses “ping-pong” autozero architecture for automatic offset correction. The op amp is designed for extreme environment applications, operating across a wide temperature range (minus 180 degree Celsius to plus 120 degree Celsius) with low offset, low drift and low power consumption. This design has been fabricated in a SiGe BiCMOS 0.5-micron process and the measured results demonstrate that the op amp is fully functional and achieves less than 40 microvolt input-referred offset voltage with …

Optimal Designs Of Mobile Nuclear Engines To Power Manned Vehicles On Mars, Robert D. Woolley

Masters Theses

This work develops original conceptual designs for compact nuclear fission reactor engines to power robust mobile equipment operating on the surface of the planet Mars. This is a nuclear application area not well explored in previous publications. Some novel analytical approaches are developed herein, including the application of optimal control theory to minimize radiation shielding mass. This work also provides the first study of using another planet's atmosphere to implement open-cycle thermal conversion systems.

To power equipment on Mars for extended durations at sustained power levels ranging from one hundred horsepower to several thousand horsepower, there is no practical alternative …

Long-Term Trends In Water Quality For A High-Elevation Stream In The Great Smoky Mountains National Park: Impacts Of Acid Deposition, Angela Vanessa Smith

Masters Theses

In the Southern Appalachians, high-elevation streams with small watershed areas tend to be sensitive to acid deposition (Deviney et al., 2006; Cook et al., 1994) because high elevations tend to have more cloud contact, leading to greater atmospheric deposition of pollutants containing sulfate and nitrate acids (Lovett and Kinsman 1990). In a recent study by Webb et al. (2004) examined the link between atmospheric acid deposition and stream water quality in brook trout (Salvelinus Fontinalis) streams in western Virginia and Shenandoah National Park (SNP). The study acknowledged that water quality improvement had been seen in response …

An Investigation Into The Effects Of Salt Concentration On Surfactant Adsorption Using A Quartz Crystal Microbalance, Shannon Joanne Ray

Masters Theses

Surfactant adsorption from aqueous electrolyte solutions onto metal surfaces was characterized through the use of a Quartz Crystal Microbalance (QCM). The need for a better understanding of the surfactant adsorption process became apparent in previous studies by Morton et al., who used estimated and extrapolated properties in a thermodynamically-based model of oil removal from metal surfaces. These modeling efforts overlap existing data on surfactant adsorption data and require an estimation of surfactant adsorption phenomena, especially the transition between monolayer adsorption and multi-layer adsorption, which corresponds to the critical micelle concentration (CMC). Thus, the purpose of this study was to gain …

Ground And Flight Vibration Environment At Fuselage Station 505 In The C-2a Airplane, Christopher David Dotson

Masters Theses

The purpose of this test was to collect ground and flight vibration data at Fuselage Station (FS) 505 in the C-2A airplane. Collection of this data was necessary to determine operational and structural compatibility of certain navigation equipment with this vibratory environment. Vibration data were collected using triaxial accelerometers mounted to the FS 505 overhead equipment shelf and to an H-764 Embedded Global Positioning System/Inertial Navigation System (EGI) mounted on the shelf. A total of 0.8 hr of ground testing and 3.6 hr of flight testing was conducted at Naval Air Warfare Center Aircraft Division Patuxent River, Maryland. Testing included …

Dynamic Target Classification In Wireless Sensor Networks, Ying Sun

Masters Theses

Information exploitation schemes with high-accuracy and low computational cost play an important role in Wireless Sensor Networks (WSNs). This thesis studies the problem of target classification in WSNs. Specifically, due to the resource constraints and dynamic nature of WSNs, we focus on the design of the energy-efficient solutionwith high accuracy for target classification in WSNs.

Feature extraction and classification are two intertwined components in pattern recognition. Our hypothesis is that for each type of target, there exists an optimal set of features in conjunction with a specific classifier, which can yield the best performance in terms of classification accuracy using …