Digital Commons Network^™

Flow Structures In An Enclosed Simplified Full Scale Under-Hood Engine Compartment During Steady State Operation, Chin Hoong Leong

Masters Theses

An experimental study of flow structures in an enclosed simplified full scale under-hood engine compartment will be conducted during steady state operation using whole field velocity measuring technique. 2D Particle Image Velocimetry (PIV) is planned for multiple cross sections in the test volume. Emphasis is given on understanding the flow structures of the 3D under-hood flow using multiple 2D PIV measurements. A recent study conducted on the engine compartment only consists of three 2D PIV measurement cross sections that sufficiently display 2D flow behavior at specific regions. Therefore, a detailed 3D flow mapping in the enclosure on various cross sections …

Synthesis And Structure Of Li6Y(Bo3)3 As A Neutron Scintillator, Emily Ann Sheats

Masters Theses

Single phase polycrystalline Li₆Y(BO₃)₃:Ce has been produced with substitutions of Ca, Sc, La, Sr, Gd, and Lu substituting for Y. Samples included isotopes of 6-Li and 11-B through isotopically enriched Li₂CO₃ and H₃BO₃. X-ray powder diffraction was used to verify the phase(s) present, while Rietveld refinements provided lattice parameters. Photoluminescence data were collected to verify Ce activation and proper location within the crystal structure. The amount of Ce and Ca were then varied to survey the best composition for scintillation properties within Li₆Y(BO₃) …

Development Of The Telemetrical Intraoperative Soft Tissue Tension Monitoring System In Total Knee Replacement With Mems And Asic Technologies, Gary To

Masters Theses

The alignment of the femoral and tibial components of the Total Knee Arthoplasty (TKA) is one of the most important factors to implant survivorship. Hence, numerous ligament balancing techniques and devices have been developed in order to accurately balance the knee intra-operatively. Spacer block, tensioner and tram adapter are instruments that allow surgeons to qualitatively balance the flexion and extension gaps during TKA. However, even with these instruments, the surgical procedure still relies on the skill and experience of the surgeon. The objective of this thesis is to develop a computerized surgical instrument that can acquire intra-operative data telemetrically for …

Artificial Neural Network For Spectrum Unfolding Bonner Sphere Data, Jia Hou

Masters Theses

The use of Bonner Sphere Spectrometer (BSS) is a well-established method of measuring the energy distribution of neutron emission sources. The purpose of this research is to apply the Generalized Regression Neural Network (GRNN), a kind of Artificial Neural Network (ANN), to predict the neutron spectrum using the count rate data from a BSS. The BSS system was simulated with the MCNP5 Monte-Carlo code to calculate the response to neutrons of different energies for each combination of thermal neutron detector and polyethylene sphere. One hundred and sixty-three different types of neutron spectra were then investigated. GRNN Training and testing was …

Image And Sieve Analysis Of Biomass Particle Sizes And Separation After Size Reduction, Yuechuan Yang

Masters Theses

Improved physical separation of biomass concentrates higher-value components, returns unused plant components to the soil, and provides a more efficient platform for downstream industrial users. Sieving and Image Analysis (IA) were studied to evaluate biomass particle sizes, particle size distribution, and potential separation of biomass materials. Switchgrass, wheat straw, and corn stover were used in the study. Particles prepared by a knife mill equipped with various screen sizes were subject to sieving test and IA. Results showed that all three biomass materials would be analyzed using the fast, easy and accurate IA. Biomass particle physical properties, such as length, width, …

A Practical Guideline For Establishing Non-Return Valve Specification And Performance Criteria, Eric W. Dawkins

Masters Theses

The non-return valve has been a standard piece of equipment in the injection molding industry since the reciprocating screw was developed. Most molders understand the role of the non-return valve in the molding process. But few understand the functional problems of the non-return valve. Because of this, the non-return valve has been considered a nuisance item for injection molders.

Wear of the non-return valve is another problem that molders are faced with. The factors contributing toward wear are not entirely understood. Material, temperatures, hours and machine size, etc., all effect the life of a valve. Consequently, most worn valves are …

Deconvolution And Segmentation Of Ground Penetrating Radar Images, Vincent Krause

Masters Theses

Ground Penetrating Radar is a valuable tool for infrastructure condition evaluation as well as in archaeology and geology. The image produced by a GPR scan can be difficult to interpret due to the weak reflection amplitude, the overlap of reflections, and due to outside interference. This thesis proposes an algorithm to automate GPR scan interpretation. This will enable maintenance engineers to read GPR scans quickly and accurately.

The proposed algorithm framework uses an optimization-based deconvolution technique followed by a segmentation process. Each column of the image is deconvoluted and thus reducing them to a list of ordered pairs of reflection …

Using Multivariate Analysis Of Geochemical Data To Better Define Hydrologic Interfaces In Surface Water - Groundwater Systems, Candice Ann Owen

Masters Theses

Groundwater-surface water interactions have been shown to be important to flow generation and stream chemistry in upland catchment environments. These areas, however, are often difficult to access making the implementation of standard hydrological surface and subsurface monitoring equipment and characterization procedures impractical, arduous and in many cases impossible due to the nature of the terrain and also regulatory guidelines for protected areas. By collecting surface water samples at distinct water contribution sites to a headwater stream, areas of groundwater influence were inferred and a hydrochemical conceptual model of a small basin was created.

The objectives of this research were to …

Correlating Grain Boundary Microstructure And Ductility Loss On Aging In Haynes® 25, Darryl Britt Glanton

Masters Theses

Haynes® 25 is a cobalt-base superalloy known for its excellent high temperature strength and corrosion resistance. However, this alloy undergoes severe embrittlement on aging at elevated temperatures. Historical research associated this ductility loss with the formation of a Co₂W Laves phase, but more recent studies have challenged the existence of this phase after prolonged aging at temperatures above 600°C. In this study, scanning and transmission electron microscopy were used to characterize the chemistry and location of precipitates in the alloy after aging at temperatures of 675 and 850°C for times up to 12,000 hours. These data were compared …

Cavitation Of Mercury In A Centrifugal Pump, David Alan Hooper

Masters Theses

Cavitation is a significant concern for the reliable operation of a centrifugal pump. Liquid metal flow loops are used in nuclear, chemical, metal forming, and liquid metal dynamo applications. Understanding of the cavitation characteristics of liquid metals is increasingly important to the design and operation of these facilities. One recent field of cavitation research has developed for mercury flow in spallation targets used in neutron sources. To further the understanding of mercury cavitation, a review of the existing literature on water cavitation, liquid metal cavitation, and mercury cavitation is performed. The mechanics of cavitation and the analytical methods applied to …

Fabrication And A Study On The Wetting Properties Of Nanostructured Surfaces, Meenaa Kalyanaraman

Masters Theses

Fluid behavior at the microscale exhibits large surface to volume ratios increasing the significance of interfacial phenomena. We have studied two microfluidic phenomena that utilize interplay between microstructure and chemical composition. The first one causes liquid droplets to roll off from surfaces with a very high contact angle. This phenomenon is called superhydrophobic behavior, can be controlled by several tuning parameters. The second one changes the wettability of liquids on a dielectric coated surface with electric potential. The experimental studies were done by first fabricating an ordered array of glass nanocones. Fiber drawing and differential glass etching processes were used …

Characterizing Groundwater-Surface Water Interactions In Great Smoky Mountains National Park Using Hydrologic, Geochemical & Isotopic Data, Amanda Marie Mckenna

Masters Theses

Groundwater-surface water interactions can substantially influence the quality of surficial water bodies and are thus important when investigating ecological health of and climate change impacts on an area. However, data collection can be hindered when the location is remote and/or legally protected. This paper presents a methodology to implement minimallyinvasive field techniques at a remote and protected location that allows preliminary identification of the relationship between groundwater and surface water. Great Smoky Mountains National Park was selected as the study area as it is subjected to some of the highest rates of acid deposition in the country. Ecological damage is …

Analysis Of Electrical Activity Of The Core Muscles Exposed To Whole-Body Vibrations While Driving A Tractor Trailer Using Electromyography Device, Harini Mangavelli

Masters Theses

Lower back disorders are observed to be the most significant problem for most of the industrial workers who operate commercial vehicles. A person sitting can have 40% higher load on the lumbar spine than when standing. Human core muscles related to spinal movement respond to rapid potential motions related to external acceleration inputs of vibration in order to control body posture, the increased muscle tension can result in muscle fatigue. The over use of muscles, vibration exposure combined with dehydration of spine and long term seating can lead to lower back pain and axial discomfort to the drivers. Electromyography (EMG) …

Developing A Technique For Evaluating Weed-Specific Mapping Systems, Philip Brooks Allen

Masters Theses

Federal regulation and public awareness of agricultural chemical use have fueled precision agriculture research for the last decade. An extensive body of research on potential reduction of herbicide inputs by automated patch-spraying or site-specific management has developed. Two dominant methods have developed for site-specific application of herbicide. Map-based systems use predefined application maps to direct herbicide application and sensor-based systems use real-time weed sensors to identify and treat weeds as the sprayer moves through the field. Weed maps, generated for map-based application of herbicide are beneficial for out-of-field decision-making but are labor intensive to create and sensitive to many types …

Modbus Implementation Using A Serial Link, Naresh Karnam

Masters Theses

Serial Communication is a process of sending one bit at a time, sequentially over a communication channel or a computer bus. RS-232 and RS- 484 are two such examples of the architecture of Serial Communication. This work primarily aims at establishing a communication channel between three entities namely the Controller also called the Console, the Relay Unit and a PC. This work aims at designing the communication model, using the Client-Server architecture and using the MODBUS protocol, as the standard for transmitting the bits in a Remote Terminal Unit (RTU) mode and for framing the characters. The MODBUS protocol also …

Analysis And Characterization Of A Sige Bicmos Low Power Operational Amplifier, Archana Yarlagadda

Masters Theses

Integrated circuit design for space applications can require radiation immunity, cryogenic operation and low power consumption. This thesis provides analysis and characterization of a SiGe BiCMOS low power operational amplifier (op amp) designed for lunar surface applications. The op amp has been fabricated on a commercially available 0.35-micron Silicon-Germanium (SiGe) BiCMOS process. The Heterojunction bipolar transistors (HBT) available in the SiGe process have been used in this op amp to take advantage of the total ionizing dose (TID) irradiation immunity and superb cryogenic operation, along with PMOS devices that show better TID immunity than their NMOS counterparts. The key features …

A Generalized Hamiltonian-Based Algorithm For Rigorous Nonequilibrium Molecular Dynamics Simulation In The Nvt Ensemble, Joseph Gerald Leo Rajkumar

Masters Theses

Using a recently developed, methodical, Hamiltonian-based procedure, we derive rigorous algorithms for nonequilibrium molecular dynamic (NEMD) simulation in the NVE and NVT ensembles. We demonstrate that the equivalence of the kinetic temperature and configurational temperatures that exists at equilibrium is maintained in nonequilibrium states, given the proper nonequilibrium expression (in the microcanonical ensemble). Specifically, we apply the procedure to the p-SLLOD algorithm, which allows for rigorous NEMD simulation in the presence of an arbitrary, externally imposed flow field. The resulting algorithms are general in that they apply in the presence or absence of external fields in addition to the imposed …

Evaluation Of Head Linear And Rotational Acceleration Response To Various Linear-Induced Impact Scenarios, Robert Paul Roy

Masters Theses

Incidents resulting in head injury generally involve components of both linear and rotational motion. The protection of the head from injury most often comes from the use of some form of helmet. Helmets currently are designed only to protect the head from linear accelerations. Recent research involving the analysis of concussion in professional football suggested that linear accelerations are more consistent in the prediction of concussion, with the resultant rotational accelerations correlating to the peak linear accelerations of the impact.

This research proposes to determine if the situation of the head impact has an effect on the correlation of the …

A Longest-Queue-First Signal Scheduling Algorithm With Quality Of Service Provisioning For An Isolated Intersection, Richard James Wunderlich

Masters Theses

In today's fast-paced society, the need to travel using automobiles is increasingly important. Aside from the road itself, the intersection is the most basic unit of a traffic system. As such, controlling the flow of traffic through intersections in an efficient manner has become a task of the utmost importance. The signal-scheduling algorithm described in this thesis is designed for just such a task. Concepts are drawn from the field of packet switching in computer networks and are applied to the traffic control problem. The method proposed utilizes a maximal weight matching algorithm to minimize the queue sizes at each …

The Detection Of Stress Corrosion Cracking In Natural Gas Pipelines Using Electromagnetic Acoustic Transducers, Austin P. Albright

Masters Theses

This thesis describes the refinement of a non-destructive, in-line inspection system sensor for the detection of stress corrosion cracks (SCCs) in natural gas pipelines. The sensors are prototype electromagnetic acoustic transducers (EMATs) for noncontact ultrasonic inspection. The focus areas discussed involve the statistically validated performance improvements achieved through the addition of 12 more features, the addition of Principal Component Analysis plus Linear Discriminant Analysis (PCA+LDA) to the classification algorithm, and most significantly the creating of a training set. The training set allowed PCA+LDA to be included in the classification algorithm, as well as allowing one set of no-flaw signature features, …

Uncertainty Analysis Of Advanced Fuel Cycles To Control Plutonium Inventories, Thomas Christopher Anderson

Masters Theses

This paper assesses the uncertainty associated with the utilization and implementation of advanced fuel cycles to control plutonium inventories. The specific fuel cycles investigated are a partially closed cycle utilizing MOX reactors and completely closed one-tier fuel cycles utilizing fast reactors. Multiple methods for assessing these uncertainties were utilized. A scenario approach that varied the time and number of the implementation of the advanced reactors was used. It was found that the implementation of 3 FR/yr with a CR of 0.5 could reduce the amount of Pu by over 36% in reference to building 3 LWR/yr. In addition to reducing …

A 64-Channel Mixed-Signal Data Acquisition System For A Solid-State High Efficiency Neutron Detector Array, Anthony Gene Antonacci

Masters Theses

This thesis presents the design of multiple analog and digital blocks required to implement a desired solid-state data acquisition system for the High Efficiency Neutron Detector Array (HENDA) project under the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL). This system encloses and is an extension of prior work described in [1] and [2]. The first prototype chip, named Patara, contained a charge sensitive front-end amplifier [2], and a semi-Gaussian shaper with baseline restore circuitry [1]. Patara III, described in this thesis, involved the addition of the following system components; two comparators, a selectable synchronous/asynchronous digital …

Effects On Level Flight Performance Of The Optimized Wind Deflector Modification For The Md-500 Helicopter, Adam Joseph Cowan

Masters Theses

This thesis investigates the effects of personnel wind deflector devices on the level flight performance of an MD-500D helicopter configured with external passenger provisions. Numerous helicopter organizations operate with external passenger configurations. These configurations result in personnel exposure to high winds and an increase in parasite drag. Level flight performance is degraded by the increase in parasite drag caused by the external passengers. Wind deflectors were mounted on the forward portion of the fuselage to protect external passengers from the effects of wind exposure (high wind loads and wind chill factor) by deflecting the wind away from the fuselage. The …

Investigation Of The Sidewall Boundary Layers In The Bidirectional Vortex Liquid Rocket Engine, Joshua W. Batterson

Masters Theses

To complement previous studies on the bidirectional vortex, we attempt to characterize viscous effects in both the axial and radial directions along the sidewall with standard asymptotic techniques. The actual boundary layer present in the chamber will be a composite of both axial and tangential shearing layers. Since the tangential velocity is completely dominant, we expect the defining characteristics of the composite boundary layer to be congruent with the tangential layer in both thickness and axial invariance. The analytic analysis is outlined first by, the formulation of the boundary layer equations via Prandtl’s method. Next, asymptotic techniques are applied to …

Impedance Matching And PspiceR Simulation Of One Atmosphere Uniform Glow Discharge Plasma (Oaugdp™) Reactor/Actuator Systems, Zhiyu Chen

Masters Theses

This thesis addresses two important issues relevant to One Atmosphere Uniform Glow Discharge Plasma (OAUGDP™) reactors and actuators ¾ impedance matching and PSpice^R simulation.

An OAUGDP™ reactor/actuator with the plasma energized can be modeled as a capacitor in parallel with a resistor. In addition, the non-ideality of the transformer between the RF power supply and the plasma reactor/actuator introduces an imaginary component in its impedance. Thus, the load of the RF power supply, as seen by its output terminals, is highly reactive. An impedance mismatch resulting from the absence of a matching network will cause a large reflected power …

A Standard Cmos Compatible Bandgap Voltage Reference With Post-Process Digitally Tunable Temperature Coefficient, Sam D. Caylor

Masters Theses

An essential element of most robust analog/mixed-signal systems is a stable and precise bandgap voltage reference (BGR). CMOS compatible BGR circuits are generally limited by variability in output drift over temperature due to process variations. In this work a CMOS BGR is developed that provides simple, digitally-controlled post-process (i.e., post fabrication) trimming. The trimming is achieved through MOSFET switches used to adjust a current gain factor for the thermal voltage referenced current within the BGR circuit. This current is proportional to absolute temperature (PTAT). The PTAT current is injected into a series connected resistor and diode to ultimately provide an …

A Study Of The Beginning Boundary Layer Influence On The Flow Field About A Two-Dimensional Automotive Model, Jonathan Gabriel Ford

Masters Theses

An experimental investigation was performed to analyze the beginning boundary layer produced on the floor of a subsonic wind tunnel and its influence on the flow field about a two-dimensional automotive model. Hot film anemometer measurements were taken in the test section of the wind tunnel operating under various inlet configurations. The use of a splitter plate and modifications to the contour of the inlet to the wind tunnel were then studied to find their affects on the height of the boundary layer in the wind tunnel test section. Finally, a 2-D automotive model was constructed with pressure taps along …

Evaluation Of Losses In Hid Electronic Ballast Using Silicon Carbide Mosfets, Lakshmi Reddy Gopi Reddy

Masters Theses

HID lamps are used in applications where high luminous intensity is desired. They are used in a wide range of applications from gymnasiums to movie theatres, from parking lots to indoor aquaria, from vehicle headlights to indoor gardening. They require ballasts during start-up and also during operation to regulate the voltage and current levels. Electronic ballasts have advantages of less weight, smooth operation, and less noisy over electromagnetic ballasts. A number of topologies are available for the electronic ballast where control of power electronic devices is exploited to achieve the performance of a ballast for lighting. A typical electronic ballast …

Investigations On Hydrocyclones For The Spallation Neutron Source, Lee Henry Hosack

Masters Theses

The hydrocyclone is commonly used to separate oil from water, and particulates from fluid streams in various process industries. Two-fluid hydrodynamic theory is used here to develop a model for hydrocyclone performance in the application of separation of helium bubbles larger than 30 micron in diameter from liquid mercury at system pressure near 1 bar. The application is related to high power liquid metal target development for proton beams used in spallation neutron sources.

Blast Resistant Design Of Steel Structures, Sarah Beth Janney

Masters Theses

The purpose of this study was to examine the load experienced by a steel blast cubicle from a surface blast test. An important objective was to determine the blast load experienced at different standoff distances and the blast resistance capability of the blast cubicle. Three cubicles with standoff distances of 20, 25, and 30ft respectively were simultaneously subjected to a 50lb TNT explosive. The manual Structures to Resist the Effects of Accidental Explosions, Army TM 5-1300 conservatively predicted the blast pressure loadings obtained from the pressure transducers mounted on the cubicles. Data collected from accelerometers was compared to results from …