Digital Commons Network^™

Cycle-Up Of Multiple Rifting Event Models: How Long Does It Take To Reach A Steady State Stress?, Lokranjith K. Ravi

University of Kentucky Master's Theses

Many geological numerical models are initiated with a background stress state of zero. Often these numerical results are compared directly to geodetic data. Recent work (Kenner and Simons, 2004) has shown that modeled deformation rates can change as the model is cycled-up following repeated earthquakes or rifting events. In this study, we investigate model cycle-up in the context of time-dependent deformation following rifting during the 1975-1984 Krafla eruption in Iceland. We consider the number of rifting cycles required for complete cycle-up, variations in cycle-up time at different locations in the model, background stress magnitudes in fully cycled-up models, and errors …

Cfd Modeling Of Heat Recovery Steam Generator And Its Components Using Fluent, Veera Venkata Sunil Kumar Vytla

University of Kentucky Master's Theses

Combined Cycle power plants have recently become a serious alternative for standard coal- and oil-fired power plants because of their high thermal efficiency, environmentally friendly operation, and short time to construct. The combined cycle plant is an integration of the gas turbine and the steam turbine, combining many of the advantages of both thermodynamic cycles using a single fuel. By recovering the heat energy in the gas turbine exhaust and using it to generate steam, the combined cycle leverages the conversion of the fuel energy at a very high efficiency. The heat recovery steam generator forms the backbone of combined …

Failure Mode Of The Weftless Bead And Evaluation Of Improved Continuous Single Wire Based Bead, Arun Kumar Doradla

University of Kentucky Master's Theses

Weftless Bead design has long been in existence and still used in many passenger car, bus, truck and agriculture tractors. The ideal bead design is a high strength flexible cable with minimal cross section and covered by rubberized nylon, rayon or steel wire side wall. The basic tire bead designs are weftless bead with rubberized ribbon of parallel wires of multiple wound layers and a continuous wire wound in sufficient number of loops to give the required strength. Weftless bead failures generally occur within about 5cm from the end of the overlapping parallel wire ribbon. The cause for this failure …

Nonlinear Transient Finite Element Simulations Of Beam Parametric Response Including Quadratic Damping, Satish N.R. Remala

University of Kentucky Master's Theses

Nonlinear parametric response of a flexible cantilever beam is simulated. In the simulations, lateral response of the beam due to an imposed axial harmonic base displacement excitation is calculated. The response frequency is approximately half the input frequency. The transient simulations include the assumption of damping proportional to the square of the velocity along the beam. Velocity-squared damping is realistic for situations in which fluid forces resisting the structural motion are significant. The commercial finite element software, ANSYS, is used to perform the simulations. A flexible method is developed and implemented in this work, based on the ANSYS Parametric Design …

Simulation Of Low-Re Flow Over A Modified Naca 4415 Airfoil With Oscillating Camber, Vamsidhar Katam

University of Kentucky Master's Theses

Recent interest in Micro Aerial Vehicles (MAVs) and Unmanned Aerial Vehicles (UAVs) have revived research on the performance of airfoils at relatively low Reynolds numbers. A common problem with low Reynolds number flow is that separation is almost inevitable without the application of some means of flow control, but understanding the nature of the separated flow is critical to designing an optimal flow control system. The current research presents results from a joint effort coupling numerical simulation and wind tunnel testing to investigate this flow regime. The primary airfoil for these studies is a modified 4415 with an adaptive actuator …

Optimization Of Machining Performance In Contour Finish Turning Operations, Masaya Hagiwara

University of Kentucky Master's Theses

Unlike straight turning, the effective cutting conditions and tool geometry in contour turning operations are changing with changing workpiece profile. This causes a wide variation in machining performance such as chip flow and chip breakability during the operation. This thesis presents a new methodology for optimizing the machining performance, namely, chip breakability and surface roughness in contour finish turning operations. First, a computer program to calculate the effective cutting conditions and tool geometry along the contour workpiece profile is developed. Second, a methodology to predict the chip side-flow for complex grooved tool inserts is formulated and integrated in the current …

Implementation And Validation Of Fault Tolerant Control Of A Self-Bearing Motor Considering Open Coil Faults, Anand Ranganathan

University of Kentucky Master's Theses

Self-bearing motor is a magnetic actuator with both bearing and motoring functionality. This work implements and validates a decoupled and fault tolerant control algorithm for the Lorentz self bearing motor containing open phase faults. The goal of the algorithm is to achieve a stable bearing force and motoring torque even with coil faults. This work simulates many non-real-time fault tolerant control models based on the algorithm using simulink. Test cases are designed in simulink and tested on these models to arrive at the best model that could be implemented in dspace for real-time control. The responses of these simulations are …

Effects Of Stochastic (Random) Surface Roughness On Hydrodynamic Lubrication Of Deterministic Asperity, Prerit Vyas

University of Kentucky Master's Theses

In order to achieve enhanced and cost-effective performance of engineering components, Surface Engineering embraces traditional and innovative surface technologies which modify the surface properties of metallic and non-metallic engineering components for specific and sometime unique engineering purposes. The surface roughness of an engineered surface may be classified as: the random surface roughness which is a product of surface finishing and the deterministic surface roughness which is engineered to increase the lubrication characteristics of the hydro dynamically lubricated thrust ring. The effect of stochastic/random roughness can not be ignored when the roughness is of the same amplitude as that of fluid …

Numerical Investigation Of The Influence Of Front Camber On The Stability Of A Compressor Airfoil, Rui Li

University of Kentucky Master's Theses

With the advent of smart materials it is becoming possible to alter the structural characteristics of turbomachine airfoils. This change in structural characteristics can include, but is not limited to, changes in the shape (morphing) of the airfoil. Through changes in the airfoil shape, aerodynamic performance can be improved. Moreover, this technique has the potential to act as a flutter suppressant. In this investigation changes in the airfoil front camber while maintaining the airfoil thickness distribution are made to increase airfoil stability. The airfoil section is representative of current low aspect ratio fan blade tip sections. To assess the influence …

Role Of Weak Zone Geometry And Rheology In The Generation Of Intraplate Seismicity, Abhishek Joshi

University of Kentucky Master's Theses

In intraplate seismic zones (e.g. the New Madrid Seismic Zone, NMSZ, in the southcentral United States), the source of stress that drives earthquake is very complex. Data from the NMSZ indicate 3 earthquake of magnitude M~7, occurring at an approximate interval of 500 years during the last 2000 years. One hypothesis that satisfies these conditions proposes that short-lived bursts of earthquakes may result from perturbations in the local or regional stress field. This causes relaxation of a lower crustal weak zone which drive repeated earthquakes. The number of earthquakes is dependent on the geometry and rheology of the weak zone. …

Statistical Analysis Of Injury Data And The Conceptual Design Of A Rollover Protective Structure For An All-Terrain Vehicle, Bhavana Parvathareddy

University of Kentucky Master's Theses

The rising statistics of fatal and non-fatal injuries involving an all-terrain vehicle has called for an analysis of the accumulated data from the past years. The analysis has led to the conclusion that in the past years, the fatal and non-fatal injuries have been rising rapidly in spite of the consent decrees which were brought into effect from 1988-1998 by the consumer product safety commission. A necessity to provide increased safety while riding an all-terrain vehicle is recognized. Rollover protective structures which were used with successful results in curbing the injuries on agricultural tractors have been identified as having a …

Quantification Of Surface Defects Using Primary Highlight In Diffuse Angle Gray Scale Images, Subburengan Ganapathiraman

University of Kentucky Master's Theses

The thesis presented is an effort to gather all possible information of one particular type of common paint defect the seed defect, from gray scale images of highly specular painted surface. The proposed approach in the thesis utilizes a white light source to illuminate the surface and utilizes a camera to capture its gray scale image at different diffused angles. While attempting to explain the physics of highlight formation in terms of location on the surface of a seed defect, the thesis also extends to utilize this information from gray scale images to accurately predict the parameters of seed defects …

A New Piezoelectric Microactuator With Transverse And Lateral Control Of Head Positioning Systems For High Density Hard Disk Drives, Younghee Han

University of Kentucky Master's Theses

In high density magnetic hard disk drives, both fast track seeking and extremely accurate positioning of the read/write head are required. A new piezoelectric microactuator with transverse and lateral control of the head positioning system for high density hard disk drives is proposed. First, the structure of the new piezoelectric microactuator is illustrated. Design of the new microactuator is based on the axial deformation of piezoelectric elements for lateral motion and the bimorph actuation of piezoelectric elements for transverse motion. Next, a mathematical model of the microactuator system is defined. Static properties associated with the displacement of the system are …

Modeling And Testing Ultra-Lightweight Thermoform-Stiffened Panels, Prathik Navalpakkam

University of Kentucky Master's Theses

Ultra-lightweight thermoformed stiffened structures are emerging as a viable option for spacecraft applications due to their advantage over inflatable structures. Although pressurization may be used for deployment, constant pressure is not required to maintain stiffness. However, thermoformed stiffening features are often locally nonlinear in their behavior under loading. This thesis has three aspects: 1) to understand stiffness properties of a thermoformed stiffened ultra-lightweight panel, 2) to develop finite element models using a phased-verification approach and 3) to verify panel response to dynamic loading. This thesis demonstrates that conventional static and dynamic testing principles can be applied to test ultra-lightweight thermoformed …

Exergy Based Method For Sustainable Energy Utilization Analysis Of A Net Shape Manufacturing System, Jayasankar Sankara

University of Kentucky Master's Theses

The approach advocated in this work implements energy/exergy analysis and indirectly an irreversibility evaluation to a continuous manufacturing process involving discrete net shape production of compact heat exchangers through a complex controlled atmosphere brazing (CAB) process. The system under consideration involves fifteen cells of a continuous ramp-up heating, melting, reactive flow, isothermal dwell, and rapid quench solidification processing sequence during a controlled atmosphere brazing of aluminum compact heat exchangers. Detailed mass, energy, and exergy balances were performed. The irreversibility sources were identified and the quality of energy utilization at different processing steps determined. It is demonstrated that advanced thermodynamics metrics …

Stress Concentration Resulting From Small Particles In A Contact Zone, Ramakanth Mudumba

University of Kentucky Master's Theses

The research on tribology and wear of the metals and composites has always been the topic of interest to understand the behavior and life of them. The wear of the materials with three-body contact has been of particular interest because the wear debris generated due to the wear and tear between the contact surfaces in constant motion will aggravate the wear rate of the contact surfaces. Hence it would be interesting to understand the stress distribution inside the materials with three-body contact. The current research presents the stress distribution within the materials which are in three-body contact modeling them as …

Experimental And Analytical Study Of Friction Stir Processing, Basil M. Darras

University of Kentucky Master's Theses

Friction stir processing (FSP) has recently become an effective microstructural modifications technique. Reported results showed that for different alloys, FSP produces very fine equiaxed and homogeneous grain structure. FSP is considered to be a new processing technique and more experimental and analytical investigations are needed to advance the industrial utilization of FSP. Most of the work that has been done in the friction stir processing field is experimental and limited modeling activities have been conducted. Attempts to develop a predictive model to correlate the resulting microstructure with process parameters are scarce. In this work, commercial 5052 Aluminum alloy sheets are …

To Forgive Is Divine, But Is It Always Helpful? Examining The Effects Of Brief Forgiveness Instructions In Helping Female Victims, Michelle K. Cardi

University of Kentucky Master's Theses

The purpose of the present study was to examine whether women who have been victimized can have a decrease in their negative affect by being exposed to the suggestion of one of two dimensions of forgiveness. The study also examined the moderating effect of several personality variables on participants reactions to the intervention. Seventy-nine women were given several personality and affect questionnaires before and after they listened to instructions for either granting forgiveness (interpersonal), letting go of their negative affect (intrapsychic), or relaxation (control). Results indicated that focusing on granting forgiveness was associated with more negative affect than the other …

The Development And Validation Of A Measure Of Positive Urgency, Melissa A. Cyders

University of Kentucky Master's Theses

The aim of the current series of studies was to begin the process of examining whether a propensity to act rashly in response to positive affective states (positive urgency) increases the likelihood of engaging in risky, maladaptive, and harmful acts. We theorized that this trait may account for some types of risky drinking behavior not explained by other risk factors, particularly for college students. In the current series of studies, an internally consistent (=.94), unidimensional scale was developed. This scale was shown to have convergent validity across methods and discriminant validity from other types of impulsivity. For both alcohol use …

Examining The Validity Of The Life History Calendar, Leslie-Ann C. Robertson Toney

University of Kentucky Master's Theses

This study examined validity of the Life History Calendar by comparing retrospective and prospective reports of adolescent substance use. Agreement was calculated using kappa and phi coefficients for dichotomous variables, and Bivariate correlations for average substance use. Effects of potential personality, psychopathology, and demographic moderators on agreement were assessed through hierarchical regression analyses and curvilinear relations determined. Results reflected moderate agreement between retrospective and prospective reports of substance use, moderated by personality and psychopathology variables, particularly Agreeableness, symptoms of antisocial personality disorder, and symptoms of substance abuse. Agreement between retrospective and prospective reports was adequate for reports of alcohol and …

Parent-Child Storytelling During Joint Picture-Book Reading And Relation To Language Scores Of Children With Adhd, Melinda A. Leonard

University of Kentucky Master's Theses

Three questions were investigated in the current study. First, do children with ADHD have language deficiencies in comparison to non-referred peers? Second, are there diagnostic group differences in parent and child storytelling when interacting in a joint picture-book setting or in parent reported home literacy habits? Third, are these differences related to child language scores? Parents of 25 children with ADHD and 39 comparison children, average age 7 years 6 months, told their children a story based on a wordless picture-book, and children then retold the story to an examiner without using the book. In addition, children made up two …

Phylogenetic Analysis Of Kentucky Strains Of Xylella Fastidiosa, J. Nicole Mundell

University of Kentucky Master's Theses

Phytopathogenic bacterium, Xylella fastidiosa, causes a number of economically important diseases, including Pierces disease (PD) of grape and bacterial leaf scorch (BLS) of a number of landscape trees. In Kentucky (KY), BLS affects a number of shade trees including many oak and maple species. In 2001, PD was diagnosed in grapevines in western KY. Xylella fastidiosa is also detected in many asymptomatic landscape plants and grasses. It was the goal of this research to identify hosts of X. fastidiosa around KY and use phylogenetic analysis to compare sequences of the 16S rDNA and gyrase B (gyrB) genes between samples. This …

Using Sequential Imagery To Evaluate Aspects Of Seed Vigor And Germination, Manjul Dutt

University of Kentucky Master's Theses

A sequential imaging system using a flat bed scanner interfaced to a personal computer was developed to study seed germination and vigor. The utility of the system was demonstrated in studies relating aspects of seed vigor in impatiens seed lots and for dormancy release in two woody perennials. Impatiens seed lots were kept in storage for 6 months to obtain a range in vigor levels. The ability to see differences at the individual seed level was possible because of the development of the sequential imaging system. It was observed that seeds deteriorated both under optimum 4OC as well as 25OC …

The Use Of A Whole Genome Scan To Find A Genetic Marker For Degenerative Suspensory Ligament Desmitis In The Peruvian Paso Horse, Diane I. Strong

University of Kentucky Master's Theses

Degenerative suspensory ligament desmitis (DSLD) is a debilitating disease of connective tissues seen in many breeds but has become prevalent in the Peruvian Pasohorse. DSLD is believed to be a genetic disorder caused by one primary founder and most likely has a recessive mode of inheritance although a dominant or co-dominant mode of inheritance has not been ruled out.

A genome scan using 259 microsatellite markers was used to test for linkage disequilibrium between one or more markers and DSLD. Two groups of Peruvian Pasohorses were selected from one population including the US and Canada. The only difference between the …