Engineering Commons^™

Structural And Signaling Elements Important For The Efficient Degradation Of Bhmt Through Macroautophagy, Carol A. Mercer

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Healthy cells maintain a dynamic and responsive intracellular environment that is marked by the synthesis and degradation of proteins, complex macromolecules and organelles. Autophagy, literally "self-eating," is a mechanism that delivers cellular cargo to the lytic compartment for digestion. Defects in the regulation of autophagy have been implicated in pathologies such as cancer and neurodegenerative disease, making the study of its regulation compelling. However, few studies have looked at the regulation of mammalian autophagy as a function of a specific cargo protein. Previous studies had indicated that the metabolic enzyme betaine homocysteine methyltransferase (BHMT) is degraded through an autophagic mechanism. …

Comparative Characterization Of Superconducting Thin Films Fabricated By Different Techniques, Padma Prasuna S. Vemulakonda

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The goal of this thesis is to compare the chemical and compositional profiles, grain structure and critical current densities of superconducting Yttrium Barium Copper Oxide(Y1Ba2Cu3O7-x or YBCO) layers grown by different competing techniques on a variety of substrates and buffer layers. The idea is to check if there can be variation of cationic ratios, impurities, possible diffusion of substrate/buffer layer atoms into the YBCO for different processing methods and microstructures. Pulsed Laser Deposition (PLD), Metal Organic Deposition (MOD) and Metal Organic Chemical Vapor Deposition (MOCVD) films on Ion Beam Assisted Deposited (IBAD)-textured buffer layers and, Rolling Assisted Biaxial textured substrate …

Algan/Gan Hemt Topology Investigation Using Measured Data And Device Modeling, Derrick Langley

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Investigation has been done on procedure, development, and verification of transistor topology for Aluminum-Gallium Nitride/Gallium Nitride (AlGaN/GaN) High-Electron Mobility Transistor (HEMTs). To date various models have been published that address modeling issues dealing with AlGaN/GaN HEMTs. Many models rely on analytic parameter solutions to help define model behavior. In order to find an optimum transistor at X-band frequency, 8-12 Gigahertz (GHz), layout, testing, modeling and simulation was conducted on various transistor topologies. Theoretical and experimental analysis has been completed for device operating point selection in measurement and modeling to account for self-heating and radio frequency (RF) dispersion effects. The model …

Data Mining And Analysis On Multiple Time Series Object Data, Chunyu Jiang

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Huge amount of data is available in our society and the need for turning such data into useful information and knowledge is urgent. Data mining is an important field addressing that need and significant progress has been achieved in the last decade. In several important application areas, data arises in the format of Multiple Time Series Object (MTSO) data, where each data object is an array of time series over a large set of features and each has an associated class or state. Very little research has been conducted towards this kind of data. Examples include computational toxicology, where each …

Xml Integrated Environment For Service-Oriented Data Management, Marwan Younes Maarouf

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The proliferation of XML as a family of related standards including a markup language (XML), formatting semantics (XSL style sheets), a linking syntax (XLINK), and appropriate data schema standards have emerged as a de facto standard for encoding and sharing data between various applications. XML is designed to be simple, easily parsed and self-describing. XML is based on and support the idea of separation of concerns: information content is separated from information rendering, and relationships between data elements are provided via simple nesting and references. As the XML content grows, the ability to handle schemaless XML documents becomes more critical …

Oxidation Resistant Coatings On Microcelluar Carbon Foam Using Simple Scalable Techniques, Dakshinamurthy Sharma Nagalingam

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Carbon foam has many applications in the fields of thermal management, net-shape composites and electronic cooling due to its porous structure, low density, electrical and thermal conductivities. However it is prone to oxidation at high temperatures in air. Whereas some previous studies have reported oxidation protective coatings on other carbon structures such as graphite parts and fibers, there is very limited work on foam. Moreover, earlier methods have used vapor phase techniques such as Plasma Vapor Deposition (PVD) and Chemical Vapor Deposition (CVD). There is no known study involving such coatings using simple scalable liquid phase method. This thesis reports …

High Performance Text Document Clustering, Yanjun Li

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Data mining, also known as knowledge discovery in database (KDD), is the process to discover interesting unknown knowledge from a large amount of data. Text mining is to apply data mining techniques to extract interesting and nontrivial information and knowledge from unstructured text. Text clustering is one of important techniques of text mining, which is the unsupervised classification of similar documents into different groups.

This research focuses on improving the performance of text clustering. We investigated the text clustering algorithms in four aspects: document representation, documents closeness measurement, high dimension reduction and parallelization. We propose a group of high performance …

An Analysis Of Neutral Drift's Effect On The Evolution Of A Ctrnn Locomotion Controller With Noisy Fitness Evaluation, Gregory Robert Kramer

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This dissertation focuses on the evolution of Continuous Time Recurrent Neural Networks (CTRNNs) as controllers for control systems. Existing research suggests that the process of neutral drift can greatly benefit evolution for problems whose fitness landscapes contain large-scale neutral networks. CTRNNs are known to be highly degenerate, providing a possible source of large-scale landscape neutrality, and existing research suggests that neutral drift benefits the evolution of simple CTRNNs. However, there has been no in-depth examination of the effects of neutral drift on complex CTRNN controllers, especially in the presence of noisy fitness evaluation. To address this problem, this dissertation presents …

Composite Data From Centrifugal Experimentation Regarding Human Information Processing, Ronald K. Butcher

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A cognitive model illustrating decrement in human performance as a function of increased G-forces has been highly sought after by the Department of Defense (DoD) for various reasons. The F-16 and other air combat platforms are super-agile aircraft that are easily capable of imposing G-forces on a pilot that are beyond human physiological limitations. Knowledge of these physiological limits and more importantly the resultant restrictions in cognitive function could prove invaluable to those who design and pilot such aircraft. The model may be utilized in the construction of improved flight simulators that incorporate more realistically performing enemy targets and therefore …

Biochemical Characterization Of Htrf1 And Htep1, Two Proteins Involved In Telomere Maintenance, Kambiz Tahmaseb

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Telomeres are the structures that protect the ends of linear chromosomes from fusion and degradation. The telomere consists of tandem repeated DNA sequences that can range from hundreds of bases to kilo-bases depending on the organism. As the cells of an organism replicate their DNA, these repeats are lost due to the end replication problem, where the ends of linear DNA cannot be fully replicated. As the telomeres are shortened through each round of replication, they eventually reach a critical point. Once the telomeres are too short and the cell risks losing coding sequences, a signaling pathway is initiated that …

Investigation Of Cylindrically-Conformed Four-Arm Spiral Antennas, Douglas J. Glass

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A four-arm spiral antenna offers broadband frequency response, wide beamwidths, reduced size compared to other antenna designs, and the ability to determine the relative direction of an incident signal with appropriate mode-forming. The reduced overall area projection of the four-arm spiral antenna compared to other antenna designs and the ability to be manufactured in a planar format allows the antenna to reside within an Unmanned Air Vehicle (UAV) fuselage. This thesis investigates the effects of cylindrically-conforming two different designs of a four-arm spiral antenna to reside within the fuselage of a medium-sized UAV. Theoretical predictions of antenna performance were created …

Improved Thresholding Technique For The Monobit Receiver, Jonathan Gordon Buck

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Wideband digital receivers typically use a very high sampling rate to capture a signal for near real-time processing. Very robust digital techniques, like the Monobit FFT technique, have been developed to provide near real-time processing of captured timedomain signals. Most of these techniques trade accuracy for processing speed by approximating computationally complex mathematical operations. The approximation sometimes makes it difficult to detect multiple signals if the difference between their amplitudes is more than a few dB. This thesis presents a dynamic thresholding technique for multi-tone signal detection. The technique is based on setting an allowable ratio between the magnitude of …

Parameterizable Channelized Wideband Digital Receiver For High Update Rate, Peter E. Buxa

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Wideband digital receivers are important components used prevalently by the United States Air Force for many modern electronic warfare systems. Currently, many digital receiver architectures are designed for a specific mission requirement and are not parameterizable, modular, or reusable for varying mission requirements. Also, many designs are technology, platform, and vendor dependent which make upgrading existing fielded systems costly and difficult. Additionally, current wideband FFT-based digital receivers must wait until a number of samples equal to the size of the FFT are collected before spectral information can be updated. Achieving a high spectral update rate is important for the accurate …

Design And Performance Evaluation Of 1 Giga Hertz Wideband Digital Receiver, Kiranraj George

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The lack of a priori knowledge about the waveform of interest, the multitudes of signals the receiver might receive, and the noise energy that occupies the same portion of the frequency spectrum as the signal makes the design of a modern wideband receiver very challenging. Especially, the receiver must be able to detect a weak signal in the presence of a strong one, which requires a high two-signal instantaneous dynamic range (IDR). To fulfill this requirement, the receiver must detect genuine weak signals and avoid the detection of strong signals' sidelobes and noise and spurs generated from the receiver system. …

Rolling Mill Optimization Using An Accurate And Rapid New Model For Mill Deflection And Strip Thickness Profile, Arif Sultan Malik

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This work presents improved technology for attaining high-quality rolled metal strip. The new technology is based on an innovative method to model both the static and dynamic characteristics of rolling mill deflection, and it applies equally to both cluster-type and non cluster-type rolling mill configurations. By effectively combining numerical Finite Element Analysis (FEA) with analytical solid mechanics, the devised approach delivers a rapid, accurate, flexible, high-fidelity model useful for optimizing many important rolling parameters. The associated static deflection model enables computation of the thickness profile and corresponding flatness of the rolled strip. Accurate methods of predicting the strip thickness profile …

Change Detection Methods For Hyperspectral Imagery, Karmon Marie Vongsy

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This thesis studies the detection of changes using hyperspectral images. Change Detection (CD) is the process of identifying and examining temporal and spectral changes in signals. Detection and analysis of change provide valuable information of possible transformations in a scene. Hyperspectral imaging (HSI) sensors are capable of collecting data at hundreds of narrow spectral bands. Such sensors provide high-resolution spatial and spectrally rich information that can be exploited for CD. This work develops and implements various CD algorithms for detection of changes using Hyperspectral images. The main objectives are to study and develop different HSI change detection algorithms. The explored …

Computational Methods For The Objective Review Of Forensic Dna Testing Results, Jason R. Gilder

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Since the advent of criminal investigations, investigators have sought a "gold standard" for the evaluation of forensic evidence. Currently, deoxyribonucleic acid (DNA) technology is the most reliable method of identification. Short Tandem Repeat (STR) DNA genotyping has the potential for impressive match statistics, but the methodology not infallible. The condition of an evidentiary sample and potential issues with the handling and testing of a sample can lead to significant issues with the interpretation of DNA testing results. Forensic DNA interpretation standards are determined by laboratory validation studies that often involve small sample sizes. This dissertation presents novel methodologies to address …

Minute Doping Of Pulsed Laser Deposition Processed Y123 Thin Films With Tb, Ce, And Pr, Joseph William Kell

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Three rare earth elements (Tb, Ce, and Pr) were chosen for the investigation into whether adding minute quantities (≤1 at%) of dopants could improve the film quality of YBa₂C ₃O_7-δ(Y123) thin films. The compositions studied are (Y_1-x,Re_x)Ba₂Cu₃O_7-δ (RE=Tb, Ce, Pr; x=0.1, 0.01, 0.001). Good quality thin films were produced by PLD and showed significant improvement to properties when exposed to a magnetic field. Ce and Pr (x=0.001) doped films showed modest improvement. However, the Tb doped system showed substantial improvement to J_c(H), with a …

Investigating The Role Of Subunit Iii In The Structure And Function Of Rhodobacter Sphaeroides Cytochrome C Oxidase, R. Ryan Geyer

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The role of subunit III (SIII) in cytochrome c oxidase structure and function was investigated using enzyme isolated from the bacterium Rhodobacter sphaeroides. Energy minimization calculations suggested that in the absence of SIII, subunit I (SI) adopted a more open conformation. This observation was tested through the use of limited proteolysis using, á-chymotrypsin. The results showed that in the absence of SIII the solution structures of wild-type and I/II oxidase were not significantly different, and that proteolysis occurred exclusively at the N and C-termini of SI. Upon inactivation of I/II oxidase by catalytic turnover, and subsequent digestion with the protease …

Summaritive Digest For Large Document Repositories With Application To E-Rulemaking, Lijun Chen

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Large document repositories need to be organized and summarized to make them more accessible and understandable. Such needs exist in many applications, including web search, e-rulemaking (electronic rulemaking) and document archiving. Even though much has been done in the areas of document clustering and summarization, there are still many new challenges and issues that need to be addressed as the repositories become larger, more prevalent and dynamic. In this dissertation, we investigate more informative ways to organize and summarize large document repositories, especially e-rulemaking feedback repositories (ERFRs), so that the large repositories can be managed and digested more efficiently and …

The Effect Of Configural Displays On Pilot Situation Awareness In Helmet-Mounted Displays, Joseph C. Jenkins

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The current research utilized configural displays within the domain of aviation to assess what design features of configural displays contribute to the formation of operator situation awareness (SA). Configural displays map system information relevant to operator goals onto geometric shapes called emergent features. An emergent feature is formed from the combination of individual line segments to produce a global feature more perceptually salient and recognized sooner than the individual parts themselves. Configural displays have been shown in previous research to provide better operator performance for integration tasks where multiple pieces of information must be considered at once, yet the design …

Development Of An Intelligent Autonomous Coffee Maker, Nicholas J. Vanderpool

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Using Intelligent Control Methodology Home coffee machines have improved over time with the addition of features such as self-activating timers and crude temperature controlled heating elements. However, home coffee brewer development has stagnated and has yet to achieve full automation status. Present coffee machines leave the user burdened with the mundane and messy task of preparing the coffee maker every time. Also, should the user decide to prepare less than an entire pot, he/she must estimate the correct amount of water and coffee to add. This can lead to a weak or strong brew, giving undesirable results. In order to …

Fpga Based Hardware Implementation Of Advanced Encryption Standard, Sowrirajan Sampath

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On October, 2, 2000, The National Institute of Standards and Technology (NIST) announced Rijndael as the new Advanced Encryption Standard (AES). The other competing algorithms were Mars, RC6, Serpent and Two-fish. The Predecessor to the AES was Data Encryption Standard (DES) which is considered to be insecure because of its vulnerability to brute force attacks. DES was a standard from 1977 and stayed until the mid 1990's. However, by the mid 1990s, it was clear that the DES's 56-bit key was no longer big enough to prevent attacks mounted on contemporary computers, which were thousands of times more powerful than …

Design And Validation Of A High-Lift Low-Pressure Turbine Blade, Mark W. Mcquilling

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This dissertation is a design and validation study of the high-lift low-pressure turbine (LPT) blade designated L2F. High-lift LPTs offer the promise of reducing the blade count in modern gas turbine engines. Decreasing the blade count can reduce development and maintenance costs and the weight of the engine, but care must be taken in order to maintain turbine section performance with fewer blades. For an equivalent amount of work extracted, lower blade counts increase blade loading in the LPT section. The high-lift LPT presented herein allows 38% fewer blades with a Zweifel loading coefficient of 1.59 and maintains the same …

Sic Schottky Diodes And Polyphase Buck Converters, Veda Prakash N. Galigekere

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The turn-on characteristics of a SiC Schottky diode are analyzed theoretically, by simulation, and by experiment. The static characteristics of SiC Schottky diodes and Si junction diodes are analyzed for normal and high temperatures. The effects of diffusion capacitance and junction capacitance on the turn-off transition of SiC Schottky diode have been analyzed theoretically. The turn-off transition of a SiC Schottky barrier diode is analyzed by modeling the metal-semiconductor junction capacitance considering the linear and the non-linear effects. Behavior of the linear and the non-linear metal-semiconductor junction capacitance models are evaluated exper- imentally. The performance of SiC Schottky diodes is …

Skin And Proximity Effects In Two Parallel Plates, Hamdi Eltayib Abdelbagi

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Time varying currents within winding and core conductors induce magnetic fields. When more than one conductor is present the resultant magnetic field can be found by adding the individual magnetic fields by superposition. The resultant magnetic field in turn induces eddy currents within each electrical component within the vicinity of the resultant magnetic field. Eddy currents flow in the opposite direction of the primary current and increase the resistance by reducing the area in which the primary current has to travel. Eddy currents also reduce the effectiveness of the conductors to conductor high frequency currents. Skin and proximity effects were …

Phase-Locked Piv Investigation Of The Effects Of The Blowing Ratio Of A Pulsed Vortex Generator Jet In A Low-Pressure Turbine, Nathan Michael Woods

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At very high altitudes the Reynolds number flow through the low pressure turbine section of the gas turbine engine can drop below 25,000. At these low Reynolds numbers the flow is laminar and extremely susceptible to separation which can lead to increased losses and reduced lift. Small jets of air injected through the suction surface of the airfoil, called Vortex Generator Jets (VGJs), have been shown successful in suppressing separation and maintaining attached flow. Pulsing of these jets has been shown to be as effective as steady jets while reducing the amount of mass flow needed. An experiment using Particle …

Bezier Surface Generation Of The Patella, Dale A. Patrick

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A method to generate control points for a given collection of data points is developed. The shape characteristics of the patella are used as a case study. The developed computer graphic techniques are demonstrated using the given data of the 3-d patella model. Generation of curved surfaces in drafting has evolved over the years from draftsman who used tools such as French curves to today's drafting being well served by being able to apply numerical analysis on the ever increasing capabilities of computer. As an everyday observed example, nature very rarely produces two shapes that are equal to another. It …

Fpga-Based Implementation Of A Digital Processor For An Instantaneous Frequency Measurement Receiver, James M. Helton

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Digital wideband receivers are essential elements used in electronic warfare (EW) applications. Instantaneous Frequency Measurement (IFM) receivers are suitable for use in EW systems due to the ultrawide instantaneous radio-frequency (RF) bandwidth, fine-frequency resolution, and moderately high sensitivity and dynamic range. Conventional IFM receivers use analog components such as power dividers, crystal video detectors, and hybrids. This research presents the architecture and design implementation of a purely digital IFM receiver based on a patented algorithm courtesy of the United States Air Force. The invention is capable of detecting a short wave pulse with 1 MHz error for every 100 nsec. …

Characterization And Modeling Methodology Of Polytetrafluoroethylene Based Reactive Materials For The Development Of Parametric Models, Stephen D. Rosencrantz

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Certain materials, when impacting a target at high velocity will chemically react due to the shock wave passing through them, thereby increasing the damage done by the material. In particular, the reactive materials of interest are capable of acting as both structure and explosive, allowing them to achieve an effect similar to a High Explosive Incindiary (HEI), without the complexity and added mass of fuses. There are a large number of materials/material combinations that could be used in reactive munitions. The purpose of this effort is to determine an efficient analytical characterization methodology that can be validated with a minimal …