Engineering Commons^™

The Role Of Amp-Activated Protein Kinase (Ampk) In Hypoxic Chemotransduction By The Carotid Body, Heidi Lynn Jordan

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The carotid bodies are small sensory organs located along the bifurcation of the carotid arteries. They detect changes in blood gases and relay this information to the brain to allow for initiation of appropriate respiratory and cardiovascular responses. A decrease in oxygen (hypoxia) sensed by the carotid body results in an increase in firing of the carotid sinus nerve and ultimately a change in one's breathing pattern. An inability to respond to an acute hypoxic (low oxygen) episode via increased ventilation may result in death or lead to pathological or chronic conditions such as stroke and hypertension (Prabhakar et.al., 2005). …

Modeling And Simulation Of A Dynamic Turbofan Engine Using Matlab/Simulink, Scott Michael Eastbourn

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A dynamic, high-bypass turbofan engine has been developed in the modeling and simulation environment of MATLAB/Simulink. Individual elements, including the fan, high pressure compressor, combustor, high pressure turbine, low pressure turbine, plenum volumes, and exit nozzle, have been combined to investigate the behavior of a typical turbofan engine throughout an aircraft mission. Special attention has been paid to the development of transient capabilities throughout the model, increasing model fidelity, eliminating algebraic constraints, and reducing simulation time through the use of advanced numerical solvers. This lessening of computation times is paramount for conducting future aircraft system-level design trade studies efficiently, as …

Measurement Of Static And Dynamic Performance Characteristics Of Electric Propulsion Systems, Aron Jon Brezina

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Today's unmanned aerial vehicles are being utilized by numerous groups around the world for various missions. Most of the smaller vehicles that have been developed use commercially-off-the-shelf parts, and little information about the performance characteristics of the propulsion systems is available in the archival literature. In light of this, the aim of the present research was to determine the performance of various small-scale propellers in the 4.0 to 6.0 inch diameter range driven by an electric motor. An experimental test stand was designed and constructed in which the propeller/electric motor was mounted in a wind tunnel for both static and …

The Role Of Angiotensin Converting Enzyme (Ace) 2 In A Murine Model Of Insulin Resistance And Albuminuria, Nathan Michael Weir

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Insulin resistance and kidney disease are intimately linked and both independently tied to dysregulation of the renin angiotensin system (RAS). The purpose of this research was to better investigate Angiotensin Converting Enzyme (ACE) 2 as a possible motif in the pathophysiology of these two disease processes. The project was divided into two parts. Part 1 investigated ACE2 KO mice as a model of albuminuria. Part 2 investigated how the lack of ACE2 enzyme affected glucose homeostasis and subsequent albuminuria.

Part 1: The Role of ACE2 in the Progression of Albuminuria. To determine if global loss of ACE2 leads to spontaneous …

Effect Of Cooling Rate And Mold Counter Pressure On The Crystallinity And Foaming Control In Microcellular Injection Molded Polypropylene Parts, Jeffrey Scott Cousineau

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Microcellular polymer injection molding is a growing industry technique due to its ability to produce dimensionally stable stress free parts while reducing cycle time, material usage, and energy costs. The process was invented by Dr. Nam P. Suh at the Massachusetts Institute of Technology in the early 1980's. The basic idea is to dissolve a supercritical fluid into the polymer melt which will nucleate and expand within the part core after injection during the cooling stage. Microcellular polymer injection molding is becoming increasingly popular in automotive, semiconductor, and industrial applications. While the technique has been widely successful using amorphous polymers, …

Structural And Electronic Properties Of Two-Dimensional Silicene, Graphene, And Related Structures, Ruiping Zhou

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Traditional CMOS (complementary metal-oxide-semiconductor) transistors have already been in the nanometer range. As bulk silicon material is approaching its physical limits, it is highly desirable to seek novel, functional materials to continue Moore's law. Two-dimensional(2D) materials, such as graphene and silicene, have attracted great attention since they were envisioned a few years ago, having extraordinary electrical properties. Research in this work was focused on understanding the structural and electronic properties of a few atomic layers of carbon (graphene) and silicon (silicene). Atomic structures of the 2D materials, corresponding band structures, and transport properties were calculated based on density functional theory. …

Isothermal Deformation And Modeling Of Ti-6al-4v, Vamsi Krishna Vempati

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Ti-6Al-4V has attractive properties such as high strength to weight ratio, good fatigue properties and excellent corrosion resistance and these properties have made this alloy an important material for the aerospace industry. In this thesis, the deformation behavior of Ti-6Al-4V with several processing histories, was studied by conducting isothermal constant strain rate compression tests over a temperature range of 829°C to 996°C (1525°F to 1825°F) and at strain rates of 10-2 s-1, 10-1 s-1 and 100 s-1. True stress versus true strain flow curves showed a peak stress followed by flow softening. The data was analyzed to obtain constitutive equations …

Ultra Low Power Read-Out Integrated Circuit Design, Jian Chen

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Carbon nanotubes (CNTs) are widely studied by the researchers in recent years, as they have small size, large strength, highly electrical and thermal conductivity. The single-walled CNT (SWNT) is readily changed in electrical resistance when exposed to gas, and has significant use in environmental monitoring, agriculture and fishing industry, chemical industry and even security. A read-out integrated circuit (ROIC) is required to detect the resistive change. In this thesis, an ultra-low power, wide dynamic detecting range and small size CMOS ROIC design is presented. This ROIC can interface wide dynamic range signal up to more than two orders (100pA-60nA) from …

Linked Open Data Alignment & Querying, Prateek Jain

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The recent emergence of the "Linked Data" approach for publishing data represents a major step forward in realizing the original vision of a web that can "understand and satisfy the requests of people and machines to use the web content" i.e. the Semantic Web. This new approach has resulted in the Linked Open Data (LOD) Cloud, which includes more than 295 large datasets contributed by experts belonging to diverse communities such as geography, entertainment, and life sciences. However, the current interlinks between datasets in the LOD Cloud, as we will illustrate,are too shallow to realize much of the benefits promised. …

Digital Wideband Spectral Sensing Receiver, Lawrence D. Burich

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Detecting, channelizing, and characterizing radio frequency signals is a fundamental requirement for electronic warfare receivers as well as in commercial wireless applications where it is important to determine activity/inactivity in specified bands for spectral sharing and interference avoidance. Spectral sensing receivers are required to cover bandwidths in the GHz range and channelize signals into frequency bins in the kilo-hertz or mega-hertz range depending on the application. The difficulty is to detect, then determine spectral characteristics of multiple signals with varying power levels and signal characteristics in real time. A number of current Digital Wideband Spectral Sensing Receiver (DWSSR) architectures are …

Integrity Monitoring Techniques For Vision Navigation Systems, Nicholas Allen Baine

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In aviation applications, navigation integrity is paramount. Integrity of GPS systems is well established with set standards. Vision based navigation systems have been found to be an adequate substitute for GPS, when it is unavailable but are unlikely to be utilized until there is a measure for system integrity. Work has been done to detect the effect of a single measurement pair being corrupted with a bias; however, the measurement geometry varies greatly with the environment. The environment could be sparse in visual features to track, or the environment could be rich with features. With more features, there is a …

Turbine Base Pressure Active Control Through Trailing Edge Blowing, Bayindir Huseyin Saracoglu

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The desire for high performance and low fuel consumption aero-engines has been pushing the limits of the turbomachinery and leading cutting-edge engine designs to fulfill the demand. The number of stages is reduced to achieve the same pressure ratios over lighter turbines. The extreme expansion requirements result in transonic-supersonic flow fields. Transonic and supersonic turbines are exposed to the shock waves that appear at the trailing edge of the airfoils, generating substantial efficiency deduction due to the interaction with the boundary layer. Furthermore, pressure fluctuations created by the shocks result in unsteady forcing on downstream components and eventually cause high …

Prediction Of Optimal Bayesian Classification Performance For Ladar Atr, Kristjan H. Greenewald

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We consider the problem of LADAR ATR classifier performance prediction in the presence of arbitrary nuisance parameters including but not limited to pose. We use several noise models for both range images and point clouds that are significantly more accurate and complex than the Gaussian models used by previous non-Monte Carlo prediction methods. Two accurate new methods of efficiently predicting the optimum Bayesian classification performance are then derived, and applied to the noise models. Advantages of these methods include significant gains in accuracy for medium to high noise levels and the ability to handle target near symmetry. Extensions are developed …

Traffic Surveillance Using Low Cost Continuous Wave (Cw) Doppler Radars, Wu Yang

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Low cost un-modulated continuous wave (CW) radar (CW Doppler radar) can be used to measure the speed of a vehicle. Traditionally, a radar gun, a lidar gun or a speed camera is used to capture a speeding vehicle. A radar gun can either measure the fastest vehicle or the vehicle with the strongest reflection. If a radar gun is used, a police officer must determine which vehicle has the speed shown on the screen of the radar gun. A lidar gun can precisely detect a speeding vehicle, but it requires precise aiming. When a camera is used, a picture will …

Characterization And Modelling Of Laser Micro-Machined Metallic Terahertz Wire Waveguides, Satya Rama Naga Lakshmi Ganti

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Terahertz radiation, a region in the electromagnetic spectrum which lies between the microwave and infrared, has gained considerable attention recently due to interesting properties exhibited by materials exposed to this radiation. Dielectric materials such as glass, paper, plastic, and ceramics that are usually opaque at optical frequencies are transparent to terahertz radiation. This led to interesting terahertz spectroscopy and imaging applications. Finite element method simulations of plain, tapered and periodically corrugated metal terahertz wire waveguides have been conducted at the end of the waveguides. This modeling was used to guide the choice of design parameters for the fabrication of waveguides …

Modeling The Exfoliation Rate Of Graphene Nanoplatelet Production And Application For Hydrogen Storage, Cory Knick

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Graphene is a unique and revolutionary new nanomaterial. A method for it's production had a U.S. patent application in 2002 (patent issued in 2006), it was produced via mechanical exfolia-tion in 2004, and subsequently the Nobel Prize in Physics was awarded in 2010 for it. These events have sparked a surge of graphene-related research. In order for graphene to be widely studied and incorporated into emerging technologies, a versatile method for large scale produc-tion of high-quality graphene is required. Current methods are either slow or expensive which limits the scale-up of graphene production. Very recently, the liquid phase exfoliation of …

'Omic' Evaluation Of The Region Specific Changes Induced By Non-Cholinergic Diisopropylfluorophosphate (Dfp) Exposure In Fischer 344 Rat Brain, Deirdre A. Mahle

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Organophosphorous compounds (OPs) are a class of serine esterase inhibitors that have widespread application as pesticides, veterinary pharmaceuticals and chemical warfare agents. Environmental contamination is ubiquitous. The threat of exposure is a concern for both military and civilian populations. Acute inhibition of acetylcholinesterase by OPs triggers a cholinergic crisis that results in muscle flaccidity, paralysis, convulsions and death. At low doses OPs can alter neuronal differentiation, cell signaling, behavior and cognition through unknown mechanisms. An imbalance of reactive oxygen species may be implicated in the adverse effects of OPs. An integrated approach using both metabolomic and transcriptomic techniques was used …

Limitations Of Functional Recovery Of Stretch Reflex Circuitry After Peripheral Nerve Regeneration, Gabrielle Marie Horstman

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Peripheral nerve regeneration fails to restore complete normal function after surgical repair of severed nerves, and this failure has primarily been attributed to errors in connecting with peripheral targets. However, recent evidence suggests that central deficits remain even after peripheral target reinnervation is largely successful. It has long been established that regeneration fails to restore the stretch reflex despite observation that many of the neural components are intact. Regenerated Ia afferents are largely successful in reinnervating muscle spindles, are capable of encoding stretch, and elicit EPSPs in homonymous motoneurons, while regenerated motor pools are capable of responding to uninjured sources …

Computational Study On Micro-Pilot Flame Ignition Strategy For A Direct Injection Stratified Charge Rotary Engine, Zachary Steven Votaw

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The Office of Security of Defense's Assured Fuels Initiative has recently been pressing for a single fuel battle space. This endeavor requires modifying many of the vehicle power plants currently in operation throughout the Armed Forces. The RQ-7 Shadow, an unmanned aerial vehicle (UAV) utilized by the Marine Corp and Army for reconnaissance purposes, is powered by UEL's AR741 rotary engine and functions on aviation fuel. One effort underway has been focused on developing this rotary engine system to operate on heavy fuels using direct injection technology and charge stratification. Although the rotary engine has many advantages over standard reciprocating …

System Optimization And Patient Translational Motion Correction For Reduction Of Artifacts In A Fan-Beam Ct Scanner, Zachary Gordon Lee Wise

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In computed tomography (CT) systems, many different artifacts may be present in the reconstructed image. These artifacts can greatly reduce image quality. For our laboratory prototype CT system, a fan-beam/cone-beam focal high-resolution computed tomography (fHRCT) scanner, the major artifacts that affect image quality are distortions due to errors in the reconstruction algorithm's geometric parameters, ring artifacts caused by uncalibrated detectors, cupping and streaking created by beam hardening, and patient-based motion artifacts. Optimization of the system was required to reduce the effects of the first three artifact types, and an algorithm for correction of translational motion was developed for the last. …

Cloudvista: A Framework For Interactive Visual Cluster Exploration Of Big Data In The Cloud, Zhen Li

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With the development and deployment of ubiquitous information sensing, mobile devices,wireless sensor networks, RFID readers, simulation, and computer generated software logs, big data have become precious resources for scientific study, business intelligence, and national security. As one of the most intuitive and effective analysis methods,visual cluster analysis remains as a significant challenge for big datasets. First, existing visualization models need to be updated to process big data in parallel. Second, processing big data inevitably bring large latency, which conflicts the requirement of interactivity. In this thesis, we develop the CloudVista framework to address the common problems with data reduction methods …

Managing Patient Test Data In Primary Care: Developing And Evaluating A System For Test Tracking To Enhance Processes, Safety, And Understanding Of Performance, Jennifer M. Cloud-Buckner

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Patient testing is vital for primary care and serves as a gateway to specialty healthcare. Patient safety is worsened when testing orders (e.g., laboratory, imaging orders) are not tracked, results are lost, or abnormal results lack patient notification and follow-up. Non-standardized testing management reduces resilience; affects clinical outcomes; and increases errors, costs, workload, and delays.

To address the need for testing management improvements, this research followed four phases in six objectives: (1) In Phase I initial survey, assess perceptions, attitudes, and behaviors of practicing healthcare clinicians and administrators about testing, safety, and technology; (2) In Phase II system design, design …

An Evaluation Of Discharge Policies At A Generic Acute Care Hospital, Elizabeth A. Crawford

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One of the main issues faced within the U.S. healthcare continuum is ineffective care transition. Ineffective transitions from one area of care to the next can lead to a reduction in quality of care, an increased risk of readmission, and an increase in healthcare costs. According to the National Transitions of Care Coalition (NTOCC), as many as 42% of the hospitals surveyed reported that care transitions during coordinated care delivery do not go as planned. One of the primary reasons for ineffective care transition is poor discharge planning. The purpose of this research is to analyze the effect of various …

Adaptive Noise Reduction Techniques For Airborne Acoustic Sensors, Ryan Michael Fuller

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Ground and marine based acoustic arrays are currently employed in a variety of military and civilian applications for the purpose of locating and identifying sources of interest. An airborne acoustic array could perform an identical role, while providing the ability to cover a larger area and pursue a target. In order to implement such a system, steps must be taken to attenuate environmental noise that interferes with the signal of interest. In this thesis, we discuss the noise sources present in an airborne environment, present currently available methods for mitigation of these sources, and propose the use of adaptive noise …

Statistical Methods For Image Change Detection With Uncertainty, Andrew James Lingg

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Sensors capable of collecting wide area motion imagery (WAMI), video synthetic aperture radar (SAR), and other high frame rate sensor modalities provide massive amounts of high-resolution data. Such data allows for the use of multiple images in exploitation tasks which may have traditionally used single images or single pairs of images. One such task is change detection. This dissertation presents new statistical methods for change detection that provide for the exploitation of multiple images per pass. Uncertainty in image registration can degrade change detection performance. Registration accuracy is analyzed, and the impact of registration uncertainty is propagated to the registered …

Knowledge Acquisition In A System, Christopher J. Thomas

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I present a method for growing the amount of knowledge available on the Web using a hermeneutic method that involves background knowledge, Information Extraction techniques and validation through discourse and use of the extracted information.

I present the metaphor of the "Circle of Knowledge on the Web". In this context, knowledge acquisition on the web is seen as analogous to the way scientific disciplines gradually increase the knowledge available in their field.

Here, formal models of interest domains are created automatically or manually and then validated by implicit and explicit validation methods before the statements in the created models can …

Abstraction Driven Application And Data Portability In Cloud Computing, Ajith Harshana Ranabahu

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Cloud computing has changed the way organizations create, manage, and evolve their applications. While many organizations are eager to use the cloud, tempted by substantial cost savings and convenience, the implications of using clouds are still not well understood. One of the major concerns in cloud adoption is the vendor lock-in of applications, caused by the heterogeneity of the numerous cloud service offerings. Vendor locked applications are difficult, if not impossible to port from one cloud system to another, forcing cloud service consumers to use undesired or suboptimal solutions. This dissertation investigates a complete and comprehensive solution to address the …

Evaluation Of Interpolation And Registration Techniques In Magnetic Resonance Image For Orthogonal Plane Super Resolution Reconstruction, Amir Pasha Mahmoudzadeh

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Super resolution reconstruction (SRR) combines several perspectives of an image (typically low resolution) in order to reconstruct a more complete and comprehensive (higher resolution) image. The aim is to use this concept on magnetic resonance imaging (MRI) data, for which the standard is to scan in several-plane orientation in a 2D fashion. As a result, clinical MRI, functional MRI (FMRI), diffusion weighted imaging (DWI)/diffusion tensor imaging (DTI), and MR angiography (MRA) tend to have high in- plane resolution but low resolution in the slice-select direction. By combining the 2 scans of the orthogonal plane, new 3D images can be reconstructed. …

Stead-State And Small-Signal Modeling Of Power-Stage Of Pwm Z-Source Converter, Veda Prakash Nagabhushana Galigekere

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Pulse-width modulated (PWM) Z-source converter plays an important role in industrial/power electronic systems. Steady-state and dynamic modeling of the power-stage of PWM converters is essential for envisaging a closed-loop regulated power supply.

Steady-state analysis of pulse-width modulated (PWM) Z-source dc-dc converter operating in continuous conduction mode (CCM) is presented. Voltage and current waveforms, and their corresponding expressions describing the steady-state operation of the PWM Z-source dc-dc converter have been presented. The input-to-output dc voltage transfer functions, both for ideal and non-ideal PWM Z-source dc-dc converter have been derived. The minimum Z-network inductance required to ensure CCM operation is derived. The …

The Role Of Ca2+ In Central Respiratory Control Neurons Of The Locus Coeruleus: Development Of The Chemosensitive Brake, Ann Nicole Imber

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Chemosensitive LC neurons increase their firing rate in response to increased CO₂ (hypercapnia) in part via inhibition of K⁺ channels. This increase gets smaller during the first two postnatal weeks (neonatal rats aged P3-P16). Alterations of this "accelerating" pathway may account for the developmental changes in the magnitude of the chemosensitive response in LC neurons. Alternatively, Ca²⁺ and Ca²⁺ channels may play a role in the response to hypercapnia, but little is known about the role of Ca²⁺ in central chemosensitivity. Whole cell patch clamp and fluorescence imaging microscopy were used to study a different …