Characterization Of Binary Offset Carrier (Boc) Systems Coexisting With Other Wideband Signals, John M. Hedenberg

Theses and Dissertations

Results for modeling, simulation, and analysis of interference effects that modern interfering signals have on the system performance of the Binary Offset Carrier (BOC) signals, such as the Global Positioning System (GPS) Military System (M-Code signal) are addressed in this work. Three signals are addressed as potential interferers. These include the current GPS clear/acquisition code (C/A-Code) signal, the current GPS precision code (P-Code) signal, and an Orthogonal Frequency Division Multiplexed (OFDM) signal. All of these potential interferers are modeled as coexisting within the same bandwidth as the M-Code signal. Interference effects are characterized by comparing the bit error performance of …

A Comparison Of The Sensor Brick Concept As A Modular System Architecture To The Realtime Control System As The Operational Architecture, James Robert Wilson

Masters Theses

This thesis describes the application of modular design into an intelligent mobile robotic system. The Sensor Brick System, a mobile robotic system infused with artificial intelligence, is derived through the concept and application of modular design. Modular design drives the system’s characterization by defining, identifying and selecting the essential composite of sub-systems that form the system architecture. The principles of modular design designate grouping the technologies into modules that facilitate maintenance of the system components and allow the rapid integration of future technological developments. Developing the operational control of the system requires an examination and comprehension of the theories of …

Kinetics Of Cellulose Dissolution In N-Methyl Morpholine-N-Oxide And Evaporative Processes Of Similar Solutions, John William Tierney

Masters Theses

The lyocell process is an environmentally friendly process for producing regenerated cellulose fibers, but is not entirely understood. The lyocell process uses the hygroscopic solvent N-methyl morpholine N-oxide (NMMO) to dissolve cellulose; the resulting solution is often termed a lyocell solution [1-4]. It is the objective of this study to better understand the process by which cellulose dissolves and the nature of lyocell solutions. By observing the disappearance of cellulose fibers into the solvent, rate data may be obtained from which kinetic parameters may be developed. Additionally an independent method for determining the concentration of cellulose in lyocell solutions was …

“Design And Verification Of A Reusable Self-Reconfigurable Gate Array Architecture, Gabriel Cozmin Chereches

Masters Theses

This thesis presents the design and verification of a Self-Reconfigurable Gate Array architecture (SRGA-UT) created for reuse, and available with a step-by-step tutorial and comprehensive documentation. The original SRGA [1], created at the University of Southern California, is an innovative architecture for a reconfigurable device that allows single cycle context switching and single cycle random access to a unified on-chip configuration/data memory. The key architecture that enables the above two features is the use of a mesh of trees based interconnect with logic cells and memory blocks at the leaf nodes and identical switches at the parent nodes.

The SRGA-UT …

Effect Of Hydrogenon On Mechanical Behavior Of A Zircaloy-4 Alloy, Elena Garlea

Masters Theses

Hydride formation is one of the main degradation mechanisms of zirconium alloys in hydrogen-rich environments. When sufficient hydrogen is present, zirconiumhydride precipitates can be formed. Cracking of the brittle hydrides near a crack tip can initiate the growth of a crack leading to the premature failure of the material. Hydride formation is believed to be enhanced by the presence of residual or applied stresses. Therefore, the increase in the stress field ahead of a crack tip may promote precipitation of additional hydrides. In order to verify these phenomena, the effect of internal stresses on the zirconium-hydride-precipitate formation, and in turn, …

The Development Of Qualification Standards For Cast Super Duplex Stainless Steel (2507 Wrought Equivalent), Vasudevan Hariharan

Masters Theses

The objective of the program is to determine the suitability of ASTM A923 “Standard Test methods for Detecting Detrimental Intermetallic Phase in Wrought Duplex Austenitic-Ferritic Stainless Steels” for 25 Cr Cast Super Duplex Stainless Steels (ASTM A890-5A).

Different tests were carried out on the materials procured from various steel foundries as stated in the ASTM A923. The foundries were designated as Foundry A, B, C and D. All the materials were foundry solution annealed. Materials from Foundry D were solution heat treated at The University of Tennessee also and then they were subjected to heat treatment schedule which was derived …

Biomimetic Membranes Realized With Arrays Of Carbon Nanofibers, Eric Hullander

Masters Theses

A microfluidic device with imbedded nanoporous membranes, constructed using a novel nanostructured material, was designed, built, modeled, and tested. The membranes were shown to be modular, and by adsorbing monodisperse latex spheres to the fibrous membrane, the pore size could be controlled. A mathematical model of the device was developed based on several existing fluidic models for transport through fibrous materials, and an image processing algorithm was designed to extract the hydrodynamic properties of the device from a series of scanning electron micrographs based on the existing hydrodynamic models. A series of experiments were performed using fluorescent microscopy to quantify …

Design Of A Novel Reluctance Motor For Industrial Applications, Weston Clute Johnson

Masters Theses

A novel reluctance motor topology, termed the Johnson-Currie Reluctance Motor (JCRM), has been developed and described in this thesis. The JCRM topology and analysis is based upon the traditional switched reluctance motor (SRM) topology although there are significant modifications.

The flux path of the JCRM topology is such that it passes through the rotor and stator in three-dimensions. This topology with three dimensional flux paths allows for the removal of discrete stator windings giving rise to vastly superior maintance to the traditional SRM and arguably to most electric motors. In addition, the usage of three-dimensions for flux paths gives rise …

Bench Scale Evaluation Of Dense Ceramic Membranes For Production Of High Purity Hydrogen From Gasification, Binay Kumar Singh

Masters Theses

Gasification for production of hydrogen and other useful gases, has achieved increasing importance in recent years. The reactions involved in gasification are favored at high temperatures and they are also limited by thermodynamic equilibrium. The development of membranes which can separate these gases under gasifier exit gas condition will significantly improve process efficiency and economics and simultaneously provide for the recovery of valuable gases. The availability of a membrane with adequate hydrogen selectivity and good thermal and mechanical stability is the key for the successful application of membrane technology in hydrogen production and separation. This work introduces a special method …

Performance Study Of Hybrid Spread Spectrum Techniques, Yachna Sharma

Masters Theses

This thesis focuses on the performance analysis of hybrid direct sequence/slow frequency hopping (DS/SFH) and hybrid direct sequence/fast frequency hopping (DS/FFH) systems under multi-user interference and Rayleigh fading. First, we analyze the performance of direct sequence spread spectrum (DSSS), slow frequency hopping (SFH) and fast frequency hopping (FFH) systems for varying processing gains under interference environment assuming equal bandwidth constraint with Binary Phase Shift Keying (BPSK) modulation and synchronous system. After thorough literature survey, we show that hybrid DS/FFH systems outperform both SFH and hybrid DS/SFH systems under Rayleigh fading and multi-user interference. Also, both hybrid DS/SFH and hybrid DS/FFH …

Managing The Remaining Service Life Of The T-34c Aircraft, John Howard Rousseau

Masters Theses

The T-34C Airplane has been the primary trainer aircraft of the United States Navy for more than twenty-five years and is reaching the end of its service life. The Navy has delayed the procurement of the replacement T-6A Texan II aircraft for five years, yet does not expect the future training requirements to diminish. This delay in T-6A procurement along with recent observed increases in primary trainer aircraft usage have resulted in the need for the Navy to pay considerable attention to the remaining service life of the T-34C aircraft.

This thesis will discuss the methodology used to determine future …

Propeller Development Process: Conflict And Cooperation Between The Department Of Defense And Civil Aviation, Nathan Grant Neblett

Masters Theses

The purpose of this thesis was to compare and contrast the acquisition of the Electronic Propeller Control System through both the Department of Defense and Civil Aviation processes controlled by the Federal Aviation Administration (FAA). The author was a planner and participant in the Department of Defense (DoD) process. Information about the Civil Aviation process was obtained via email and telephone communication with participants, some of whom aided both processes.

Strong similarities existed in system design and prototype manufacture for both processes. A large portion of developmental flight test was similar, if not identical. In particular, both the DoD and …

A Numerical Study Of Curved Labyrinth Seals For Steam Turbines, Sricharan Kishore Ayyalasomayajula

Masters Theses

A numerical experiment has been conducted to study and evaluate the structural behavior of newly designed labyrinth seals. Structural analysis was performed to understand, evaluate and compare new seals with a baseline straight seal that is typical of commonly used seals in steam turbines. New configurations of labyrinth seal knives were developed for use in steam turbines [17]. The main objective of this study is to develop a better understanding of selected various labyrinth seals that may be configured to minimize the steam leakage and reduce seal interactions with the shaft. Computational fluid dynamic modeling of the various configurations, from …

An Experimental Evaluation Of The Constant Β Relating The Contact Stiffness To The Contact Area In Nanoindentation, Jeremy Harper Strader

Masters Theses

Measurements of mechanical properties by nanoindentation with triangular pyramidal indenters like the Berkovich rely heavily upon the relationship between the contact stiffness, S, the contact area, A, and the reduced elastic modulus, E_r . This relationship is often written in the form: S = 2βEr(A/π)1/2, where βis a constant that depends on the geometry of the indenter. Although the most common values for βused in experimental measurements are 1.000 and 1.034, various theoretical analyses have yielded values as small as 1.00 or as large as 1.2, depending on the assumptions made to model the deformation. Here the most appropriate …

Flight Testing Quadeye The First Night Vision Helmet Mounted Cueing System For Fixed Wing Jet Aircraft, Timothy Ghannon Burton

Masters Theses

In 2002 the United States Navy introduced helmet mounted cueing systems (HMCS) into tactical jet operations. As aircrews have become more reliant on their HMCS the requirement for a night vision capable cueing system has risen to the forefront of HMCS technology. One proposed solution to this requirement was Quadeye. Quadeye is a wide-angle (100deg field of view) four cathode-ray tube system with injected Joint Helmet Mounted Cueing video. The Navy flew 8 evaluation sorties from March to August 2005, in the F-18 A-F fighter aircraft. The goal of this limited scope effort was to answer four questions:

1. Does the …

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Bio-Derived Fuels For Hybrid Rocket Motors, Joshua David Scholes

Masters Theses

Two bio-derived fuels have been successfully tested in a laboratory scale hybrid rocket combustion chamber located at the University of Tennessee, Knoxville. Pure lard soaked in an open cell sponge matrix and beeswax were both tested using gaseous oxygen as the oxidizer. Given similar testing conditions, these fuels exhibit higher regression rates than the common hybrid rocket propellant HTPB (hydroxyl-terminated polybutadiene), thus overcoming one of the main shortcomings of hybrid rocket fuels. These fuels also have similar or higher regression rates than paraffin-based fuels recently tested by a Stanford University/NASA Ames team. Measured thrusts ranged from 20-140 Newtons, and calculated …

Solving Low Frequency Electromagnetic Problems With Fast Solvers, W. C. Chew, L. (Lijun) J. Jiang, Y. H. Chu, Y. A. Liu, M. K. Li, Z. G. Qian, J. Xiong, L. Sun

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

Dynamic Growth Rates Of Microbial Populations In Activated Sludge Systems, Peter George Stroot, Pascal E. Saikaly, Daniel B. Oerther

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Results of mathematical modeling and whole cell 16S ribosomal RNA-targeted fluorescence in situ hybridizations challenge the widely held perception that microbial populations in "steady-state" activated sludge systems share a common net growth rate that is proportional to the inverse of the mean cell residence time. Our results are significant because they encourage bioprocess engineers to appreciate the differences in growth physiology among individual microbial populations in complex mixed microbial communities such as suspended growth activated sludge bioreactor systems.

Dynamic Determinants Of Incisal Display, Shawn Paul Pesh

Loma Linda University Electronic Theses, Dissertations & Projects

The principal objective of this study was to use computer aided design (CAD) to better illustrate and quantify the relationship of mandibular arch depth, mandibular arch width, overbite, and overjet in the presence of mandibular dental crowding. To date, there has been no research examining how changes in the mandibular arch limit the orthodontist's ability to control overbite and overjet. Understanding how to effectively manage overbite and overjet are crucial to the clinician's ability to manipulate incisal display. Polyvinyl siloxane impressions of both maxillary and mandibular arches of a Caucasian patient were taken and used to pour dental stone models. …

Disposal Of Bridge Paint Residue, Theodore Hopwood Ii, Sudhir Palle

Kentucky Transportation Center Research Report

Paint residue generated by bridge maintenance painting commonly contains lead requiring the residue to be disposed of as a hazardous waste. Several alternatives are being investigated in this study, chemical stabilization and recycling as options for the Kentucky Transportation Cabinet (KYTC) to consider in addressing the waste stream generated by bridge maintenance painting operations.

In the initial portion of this study, four chemical stabilization materials were identified as candidates for xperimental/demonstration projects entailing maintenance painting. A recycling option was also provided. An experimental bridge painting project was let by KYTC to investigate the use of two chemical stabilizers and the …

Today’S Dot And The Quest For More Accountable Organizational Structures, Lenahan O'Connell, Juita-Elena (Wie) Yusuf, Merl Hackbart, Donald L. Hartman, Candice Wallace, Doug Kreis

Kentucky Transportation Center Research Report

This study investigates the impact of DOT organizational structures on effective transportation planning and performance. A review of the 50 state DOT authorizing statutes and DOT organizational charts found minimal differences in organizational structures among the states. However, 37 states have quasi-independent commissions (sometimes called boards, or councils.) A statistical analysis showed that the commission states have higher Government Performance Project (GPP) scores than the non-commission states. The analysis suggested that effective commissions avoid having members represent geographical regions and political parties and avoid giving the commission the power to select the director of the DOT. In addition the states …

Fiscal Year 2005 Fhwa-536 Report For The Kentucky Transportation Cabinet, Steven Douglas Kreis

Kentucky Transportation Center Research Report

The Federal Highway Administration (FHWA) requires state transportation agencies to submit a biennial report on local highway finances. The purpose of these reports is to provide FHWA with the data it needs to capture the financing of highway activities at the local level. Based on this information, it can identify trends in revenue, expenditures, investments, and program development, and in turn make decisions about future investments. The report, FHWA-536, asks agencies to report on four areas of local highway finance: 1) disposition of highway-user revenues; 2) revenues used for roads and streets identified by source and funding type; 3) road …

Temperature Control Of The Online Rheological Sensor, Larry Scott Spencer

Masters Theses

Rheometers are devices that can be used to measure the rheological properties of polymers. Online rheometers test for rheological properties during a polymer process. Real-time rheological data would eliminate any time delays that accompany off-line rheometers and would provide the feedback information needed for tighter polymer process control. A real-time control system would eliminate the need for an offline rheometer to analyze polymer product properties, thus saving both time and money.

The Online Rheological Sensor was used to estimate the shear and elongational viscosities of a polymer from measured variables during processing. The Online Rheological Sensor was mounted on a …

Modeling Of Capacitor Impedance In Switching Converters, Jonathan W. Kimball, Philip T. Krein, Kevin R. Cahill

Electrical and Computer Engineering Faculty Research & Creative Works

Switched capacitor (SC) converters are gaining acceptance as alternatives to traditional, inductor-based switching power converters. Proper design of SC converters requires an understanding of all loss sources and their impacts on circuit operation. In the present work, an equivalent resistance method is developed for analysis, and equivalent resistance formulae are presented for various modes of operation. Quasiresonant converters are explored and compared to standard SC converters. Comparisons to inductor-based switching power converters are made. A number of capacitor technologies are evaluated and compared for applications to both SC converters and inductor-based converters. The resulting model can be used to accurately …

A Novel Method For Determination Of Dielectric Properties Of Materials Using A Combined Embedded Modulated Scattering And Near-Field Microwave Techniques-Part Ii: Dielectric Property Recalculation, R. Zoughi, Dana Hughes

Electrical and Computer Engineering Faculty Research & Creative Works

The use of combined embedded modulated scattering technique and near-field microwave nondestructive testing techniques is investigated as a novel method for evaluating the dielectric properties of a material. The forward formulation for determining the reflection coefficient at the aperture of a waveguide radiating into a dielectric half-space in which a PIN diode-loaded dipole (i.e., modulated scattering technique probe) is embedded was presented in Part I of this paper. Here, in Part II, the recalculation of the dielectric properties, using the results of the forward model, is presented along with some associated experimental results.

Approaches For Autonomous Vehicles In Civil Airspace: Giving Sight To The Blind, Nicholas Scott Hardman

Masters Theses

The growing prevalence of unmanned aerial vehicles (UAVs) brings great potential for public benefit, but in order to fly in civil airspace UAVs must avoid traffic without the benefit of an onboard human. Developing this capability presents many system integration challenges.

This report examines the integration of automated detect, see, and avoid (DSA) systems on aircraft. For context, the need for UAV operations is reviewed. The report then examines how DSA fits into the entire framework for aviation safety. The research, test results, and conclusions that follow provide the necessary information to decide:

• how to test and evaluate new …

Socio-Economic Analysis Of Fatal Crash Trends (Final Report), Adam Kirk, Jerry G. Pigman, Kenneth R. Agent

Kentucky Transportation Center Research Report

This report describes the analysis of fatal crash patterns and explores the impact of socioeconomic factors and safety regulations on statewide crash rates. This analysis separated statewide crash rates between 2002 and 2004 into two samples, 1) those with crash rates 25 percent greater than the average national rate and 2) those with crash rates lower than this threshold. Safety regulations and socioeconomic factors were identified as having a significant effect on crash rates, with socioeconomic factors showing a higher potential to explain differences in crash rates between the two samples.

An Investigation Of Employee Satisfaction And Employee Empowerment Specific To On-Site Supervisors In The Residential Construction Industry, David Lars Halvorsen

Theses and Dissertations

Employee satisfaction and empowerment are vital elements to businesses in most industries. The construction industry has various types of employees, ranging from managers and executives to on-site supervisors and laborers. This study was conducted to obtain a greater understanding about the elements and levels of satisfaction and empowerment of on-site supervisors in the residential construction industry. An on-site supervisor in the residential construction industry is responsible for coordinating and managing employees, materials, equipment, budgets, schedules, contracts, and the safety of employees and the general public. They are also the employees most frequently perceived as accountable for the success or failure …

Preliminary Design Approach For Prosthetic Ankle Joints Using Compliant Mechanisms, Jason Matthew Wiersdorf

Theses and Dissertations

The objective of this thesis is to develop design approaches and models for prosthetic ankle joints using kinematic models of the human ankle and compliant mechanisms technology. Compliant mechanisms offer several potential design advantages over traditional rigid-body designs including high reliability and low cost. These design advantages are ideal for use in prosthetics. Some prosthetic ankle/foot systems currently on the market have multiple degrees of freedom yet are expensive. Additionally, even though these systems have multiple degrees of freedom, none of them are designed after the actual movements of the biological ankle. In this thesis a two, single degree-of-freedom hinge …

Linking Channel Stability And Bed Sediment Characteristics To Biological Integrity In Tennessee Ridge And Valley Streams, Kelley H. Williams

Masters Theses

Streambed sedimentation has plagued waterways since the beginning of civilization, whether as a natural flow process or human disturbances on the landscape in more recent times. Due to the continual degradation in the quantity and diversity of aquatic organisms within streams, the issue has finally surfaced as a significant concern. The need to develop better Total Maximum Daily Load (TMDL) assessment tools to link sediment impairment to biological integrity was the driving force behind this study.

Within the Ridge and Valley Ecoregion, 76 stream reaches were analyzed to investigate the impacts of stability issues and bed sediment characteristics on stream …