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Articles 86251 - 86280 of 197010

Full-Text Articles in Engineering

The Electrophysiology Of Resting State Fmri Networks, Carl David Hacker May 2017

The Electrophysiology Of Resting State Fmri Networks, Carl David Hacker

McKelvey School of Engineering Graduate Student Theses & Dissertations

Traditional research in neuroscience has studied the topography of specific brain functions largely by presenting stimuli or imposing tasks and measuring evoked brain activity. This paradigm has dominated neuroscience for 50 years. Recently, investigations of brain activity in the resting state, most frequently using functional magnetic resonance imaging (fMRI), have revealed spontaneous correlations within widely distributed brain regions known as resting state networks (RSNs). Variability in RSNs across individuals has found to systematically relate to numerous diseases as well as differences in cognitive performance within specific domains. However, the relationship between spontaneous fMRI activity and the underlying neurophysiology is not …


Characterizing Structure, Properties, And Deformation In Metallic Glasses And Olivine Using Instrumented Nanoindentation, Kelly Kranjc May 2017

Characterizing Structure, Properties, And Deformation In Metallic Glasses And Olivine Using Instrumented Nanoindentation, Kelly Kranjc

McKelvey School of Engineering Graduate Student Theses & Dissertations

Micro- and nanomechanical testing can provide significant insight about the structure, properties, and behavior of materials. These techniques are nondestructive, require only limited amounts of material, and have been known to detect a brittle-to-ductile transition in mechanical behavior due to a size effect. This work utilizes this type of testing to explore fundamental questions about the structure, properties, and behavior of two disparate material systems: metallic glasses and olivine.

Metallic glasses are metallic alloys devoid of any long-range order. Their unique atomic structure imbues them with properties such as a high elastic strain limit, near-theoretical strengths, and the ability to …


Using Pet/Mri To Assess Hepatic Radioembolization Of Yttrium-90 Microspheres, Nichole Millward Maughan May 2017

Using Pet/Mri To Assess Hepatic Radioembolization Of Yttrium-90 Microspheres, Nichole Millward Maughan

McKelvey School of Engineering Graduate Student Theses & Dissertations

Radioembolization of yttrium-90 (Y-90) microspheres is used to treat primary and secondary cancers in the liver. Though this therapy has existed for decades, the treatment is not well optimized from treatment planning to post-procedural assessment. Recently, there has been a surge to utilize the small positron yield from the radioactive decay of Y-90 for post-radioembolization positron emission tomography (PET) imaging of the microsphere activity distribution. These images provide promise for dosimetry assessment, identifying extrahepatic uptake and possible under-dosed lesions that may benefit from subsequent therapy. However, due to the low positron statistics and high flux of Bremsstrahlung radiation, PET imaging …


Uncertainty Quantification Of Wall-Modeled Large Eddy Simulation (Wmles) Model In Openfoam, Zuoxian Hou May 2017

Uncertainty Quantification Of Wall-Modeled Large Eddy Simulation (Wmles) Model In Openfoam, Zuoxian Hou

McKelvey School of Engineering Graduate Student Theses & Dissertations

In this thesis, a non-intrusive uncertainty quantification (UQ) method is used to improve the accuracy of a wall-modeled large eddy simulation (WMLES) model. Detailed UQ studies focusing on the closure coefficients of two LES models are performed. A non-intrusive polynomial chaos model is used to evaluate output sensitivities and uncertainties in the entire flow domain. The proposed UQ method allows for the investigation of specific flow features and phenomena within the domain. The results of the UQ analyses are then used to identify which turbulence model closure coefficients most influence the flow features of interest. Sobol indices of closure coefficients …


Development And Applications Of Novel Fluorescent Molecular Probe Strategies, Dolonchampa Maji May 2017

Development And Applications Of Novel Fluorescent Molecular Probe Strategies, Dolonchampa Maji

McKelvey School of Engineering Graduate Student Theses & Dissertations

Optical imaging and spectroscopy technologies offer the ability to provide structural and functional information in a fast, low-cost, ionizing radiation free, highly sensitive and high throughput fashion. The diverse contrast mechanisms and complementary imaging platforms form the foundation for the application of optical imaging in pre-clinical studies of pathophysiological development as well as direct clinical application as a tool for diagnosis and therapy. Fluorescence imaging techniques have been one of the most rapidly adopted methods in biology and biomedicine. Visualization of biological processes and pathologic conditions at the cellular and tissue levels largely relies on the use of exogenous fluorophores …


Underwater Celestial Navigation Using The Polarization Of Light Fields, Samuel Bear Powell May 2017

Underwater Celestial Navigation Using The Polarization Of Light Fields, Samuel Bear Powell

McKelvey School of Engineering Graduate Student Theses & Dissertations

Global-scale underwater navigation presents challenges that modern technology has not solved. Current technologies drift and accumulate errors over time (inertial measurement), are accurate but short-distance (acoustic), or do not sufficiently penetrate the air-water interface (radio and GPS). To address these issues, I have developed a new mode of underwater navigation based on the passive observation of patterns in the polarization of in-water light. These patterns can be used to infer the sun__s relative position, which enables the use of celestial navigation in the underwater environment. I have developed an underwater polarization video camera based on a bio-inspired polarization image sensor …


An Investigation Of Geography And Climate Induced Distresses Patterns On Airfield Pavements At Us Air Force Installations, L K. Sahagun, M Karakouzian, A Paz-Cruz, H De La Fuente Mella May 2017

An Investigation Of Geography And Climate Induced Distresses Patterns On Airfield Pavements At Us Air Force Installations, L K. Sahagun, M Karakouzian, A Paz-Cruz, H De La Fuente Mella

Civil and Environmental Engineering and Construction Faculty Research

This study investigated climate induced distresses patterns on airfield pavements at US Air Force installations. A literature review and surveys of Pavement Condition Index indicated that the predominant factor contributing to the development of pavement distress was climate. Results suggested that, within each type of pavement distress, a geographic pattern exists which is strongly correlated to conventional US climate zones. The US Air Force Roll-Up Database, housing over 50,000 records of pavement distress data, was distilled using a process designed to combine similar distresses while accounting for age and size of samples. The process reduced the data to a format …


Facilitating High Performance Code Parallelization, Maria Abi Saad May 2017

Facilitating High Performance Code Parallelization, Maria Abi Saad

Dissertations - ALL

With the surge of social media on one hand and the ease of obtaining information due to cheap sensing devices and open source APIs on the other hand, the amount of data that can be processed is as well vastly increasing. In addition, the world of computing has recently been witnessing a growing shift towards massively parallel distributed systems due to the increasing importance of transforming data into knowledge in today’s data-driven world. At the core of data analysis for all sorts of applications lies pattern matching. Therefore, parallelizing pattern matching algorithms should be made efficient in order to cater …


Improving Distribution And Absorption Of Light In Microalgal Photobioreactors Through Plasmon Enhancement, Entrapped Cultivation And Controlled Motion, Bendy Estime May 2017

Improving Distribution And Absorption Of Light In Microalgal Photobioreactors Through Plasmon Enhancement, Entrapped Cultivation And Controlled Motion, Bendy Estime

Dissertations - ALL

Microalgae represent a promising source of renewable biomass for the production of biofuels and valuable chemicals. However, the development of high throughput microalgal cultivation methods and energy efficient biomass harvesting technology is necessary to improve the economic viability of large scale microalgal biomass production.

The issue of poor distribution and absorption of light is one of the hurdle that can be addressed to improve the productivity in microalgal cultivation systems. As it happens, microalgal photosynthetic activities have shown great dependence on the irradiance to which the microalgal cells are exposed. Quantitatively, microalgal growth increases with increasing light intensity until a …


Extraction And Localization Of Noise-Related Flow Structures In High Speed Jets, Pinqing Kan May 2017

Extraction And Localization Of Noise-Related Flow Structures In High Speed Jets, Pinqing Kan

Dissertations - ALL

The jet noise problem, or the noise radiation from high-speed flow interactions, still remains unresolved after over sixty years of research. With the growing aviation industry, more communities are exposed to noise pollution from aircrafts; and better control strategies are needed to meet the more stringent noise regulations.

This thesis analyzes two sets of high-speed jet flow data and aims at better understanding the flow dynamics and noise radiation mechanism. The first set of data consists of subsonic / transonic axisymmetric jets and the second dataset is of a more advanced configuration: a two-stream supersonic rectangular jet with a flat …


Design And Behavior Of Steel Delta Girders, Omar El Masri May 2017

Design And Behavior Of Steel Delta Girders, Omar El Masri

Dissertations - ALL

In steel structures, I-sections are commonly used for beams and columns. These cross-sections usually lack lateral rigidity and torsional stiffness. An effective method to improve their lateral rigidity and overall flexural resistance is to weld two inclined rectangular plates to the compression flange and the compression portion of the web of hot-rolled or welded I-section to form what is known as a Delta girder. This mixed cross-section, i.e., cross-section composed of an open profile attached to a closed profile, can provide enhanced torsional stiffness and hence noticeably higher lateral-torsional buckling (LTB) capacity for the beam. While Delta girders can be …


Combining Smart Material Platforms And New Computational Tools To Investigate Cell Motility Behavior And Control, Megan Brasch May 2017

Combining Smart Material Platforms And New Computational Tools To Investigate Cell Motility Behavior And Control, Megan Brasch

Dissertations - ALL

Cell-extracellular matrix (ECM) interactions play a critical role in regulating important biological phenomena, including morphogenesis, tissue repair, and disease states. In vivo, cells are subjected to various mechanical, chemical, and electrical cues to collectively guide their functionality within a specific microenvironment. To better understand the mechanisms regulating cell adhesive, differentiation, and motility dynamics, researchers have developed in vitro platforms to synthetically mimic native tissue responses. While important information about cell-ECM interactions have been revealed using these systems, a knowledge gap currently exists regarding how cell responses in static environments relate to the dynamic cell-ECM interaction behaviors observed in vivo. Advances …


Experimental And Modeling Study Of Ignition-Resistant Fuels, Apeng Zhou May 2017

Experimental And Modeling Study Of Ignition-Resistant Fuels, Apeng Zhou

Dissertations - ALL

This research investigates relative ignition behavior of some oxygenated fuels and their

blends with gasoline surrogates. It seeks to identify fuels with higher resistance to ignition

and validate tentative kinetic models intended to predict their combustion chemistry. It

also develops a method for simplified ignition delay time correlation that can allow for a

more rapid estimation of the ignition behavior of a given fuel at known thermodynamic

conditions.

The work is motivated by the fact that in spark-ignition (SI) engines, increasing energy

conversion efficiency through increasing the engine compression ratio is limited by the

phenomenon of undesired autoignition known as …


Multidataset Independent Subspace Analysis: A Framework For Analysis Of Multimodal, Multi-Subject Brain Imaging Data, Rogers F. Silva May 2017

Multidataset Independent Subspace Analysis: A Framework For Analysis Of Multimodal, Multi-Subject Brain Imaging Data, Rogers F. Silva

Electrical and Computer Engineering ETDs

Mental illnesses are serious disorders of the brain that have devastating effects on individuals and society. In addition to their disabling and impairing effects, mental illnesses have deep social and economical implications, accounting for an estimated loss of 12 billion working days and a care cost surge to $6 trillion a year by 2030. For diseases such as depression and anxiety, enhancing preventive programs and treatment accessibility, in combination with accurate early diagnosis and personalized treatments, are projected to result in a four-fold return on every dollar invested, a strategy that can drastically help curtail those losses. Notably, within the …


An Experimental And Numerical Study Of Nanomechanical Behavior Of Hard/Soft Multilayered Coatings, Benigno Sandoval May 2017

An Experimental And Numerical Study Of Nanomechanical Behavior Of Hard/Soft Multilayered Coatings, Benigno Sandoval

Mechanical Engineering ETDs

Multilayer thin film composites, sometimes referred to as nanolaminates, have emerged as an important subset of materials with novel, and often tunable, properties such as high strength, high toughness, and resistance to wear or corrosion. Often fabricated using alternating layers of two or more materials, these multilayer thin film coatings are typically expensive and time intensive to fabricate and characterize and exhibit novel responses to nanomechanical testing such as plasticity during unloading. This thesis explores the nanoindentation response of hard/soft multilayer coatings through examination of the optical coating Al/SiC and similar coating Al/SiO2. Instrumented indentation was used to study single …


Simulation And Analysis Of The Band-Agile Coaxial Backward-Wave Oscillator, Phillip H. Fansler May 2017

Simulation And Analysis Of The Band-Agile Coaxial Backward-Wave Oscillator, Phillip H. Fansler

Electrical and Computer Engineering ETDs

Simulation of a Band-Agile Coaxial Backward-Wave Oscillator (BACoRBWO) pro- duced a device that is tunable to operate in two distinct bands: L-band (1.4GHz) at 1.9GW with an efficiency of 26%, and C-band (4.2GHz) at 1.1GW with an efficiency of 15%. The device does not perform as expected based on existing literature; how- ever the end result is not necessarily undesirable. The need for further exploration of the discrepancies between contemporary literature and our findings notwithstanding, this device operates well enough of its own accord to merit additional study.


Thermoreflectance Technique For Thermal Properties Measurement Of Micro/Nanoscale Cantilever Beams, Mirza M. Elahi May 2017

Thermoreflectance Technique For Thermal Properties Measurement Of Micro/Nanoscale Cantilever Beams, Mirza M. Elahi

Electrical and Computer Engineering ETDs

Thermal property analysis of thin film materials on a semi-infinite substrate is a very important area of research in last few decades due to the deviation of their properties from its bulk values and measurement technique plays very important role to be free from the effect of interface conductance, surface impurities, convective and radiative losses and fabrication tolerances. Non-contact optical measurement technique drew attention to be applicable to measure thermal properties using pump-probe thermoreflectance where short pulse Laser beam applied to the film to avoid heat loss with the inclusion of the interfacial conductance and extract thermal diffusivity which is …


Insulin, Glucose, And Β-Cell Diffusion Analysis, Matthew Usevitch, Alonzo Cook May 2017

Insulin, Glucose, And Β-Cell Diffusion Analysis, Matthew Usevitch, Alonzo Cook

Journal of Undergraduate Research

The purpose of this project is to further understand the function of extruded polytetrafluoroethylene (ePTFE) membranes in the pursuit of creating an implantable, removable pancreas device. This device would be filled with pancreas cells and automatically regulate blood sugar for patients with diabetes. Dr. Alonzo Cook’s lab is currently pursuing understanding the process of taking a patient’s own cells, reprogramming them into stem cells, and then differentiating them into pancreas cells. The device that is the end goal of this project is the main foreseen use of these differentiated pancreas cells. This project focuses on studying how essential nutrients diffuse …


The Replacement Of Network Switches, Sean Fenton May 2017

The Replacement Of Network Switches, Sean Fenton

Undergraduate University Honors Capstones

Networking equipment often has to be replaced every few years in order to keep up with network speed demands and bandwidth, as well as the expiration of equipment. Gallaudet’s network switches were approaching their End of Life (EoL) and the Gallaudet networking team decided to replace the networking equipment to improve the network efficiency at Gallaudet. After much research and debate, the decision was made to replace current Cisco networking equipment with Juniper in order to optimize the network speed for Internet traffic. Cisco and Juniper are competing brands for a wide range of networking equipment. The capstone project is …


Impacts Of Professional Development In Integrated Stem Education On Teacher Self-Efficacy, Outcome Expectancy, And Stem Career Awareness, John Geoffrey Knowles May 2017

Impacts Of Professional Development In Integrated Stem Education On Teacher Self-Efficacy, Outcome Expectancy, And Stem Career Awareness, John Geoffrey Knowles

Purdue Polytechnic Doctoral Dissertations

This research analyzed the effects of teacher professional development and lesson implementation in integrated Science, Technology, Engineering, and Math (STEM) on: 1.) Teacher self-efficacy and their confidence to teach specific STEM subjects; 2.) Teaching outcome expectancy beliefs concerning the impact of actions by teachers on student learning; and 3.) Teacher awareness of STEM careers. High school science and technology education teachers participating in the Teachers and Researchers Advancing Integrated Lessons in STEM (TRAILS) project experimental group attended a ten-day summer professional development institute designed to educate teachers in using an integrated STEM education model to implement integrated STEM lessons. The …


Pavement Surface Distress Detection, Assessment, And Modeling Using Geospatial Techniques, Su Zhang May 2017

Pavement Surface Distress Detection, Assessment, And Modeling Using Geospatial Techniques, Su Zhang

Civil Engineering ETDs

Roadway pavement surface distress information is essential for effective pavement asset management, and subsequently, transportation agencies at all levels dedicate a large amount of time and money to routinely collect data on pavement surface distress conditions as the core of their asset management programs. These data are used by these agencies to make maintenance and repair decisions. Current methods for pavement surface distress evaluation are time-consuming and expensive. Geospatial technologies provide new methods for evaluating pavement surface distress condition that can supplement or substitute for currently-adopted evaluation methods. However, few previous studies have explored the utility of geospatial technologies for …


Synthesis And Characterization Of Molybdenum Sulfide And For Hydrogen Evolution Reaction And Supercapacitor Applications, Zhuo Wang May 2017

Synthesis And Characterization Of Molybdenum Sulfide And For Hydrogen Evolution Reaction And Supercapacitor Applications, Zhuo Wang

Electronic Theses & Dissertations

To meet the constantly rising requirement of energy other than traditional fossil fuel and environment protection, it is a perfect time to development low cost, and efficient materials for clean energy production. Hydrogen generation by water splitting is one of the cleanest ways to produce cheaper energy. Hydrogen evolution reaction (HER) is one of the key steps in water splitting process. Ideally, the thermodynamic potential for HER should be at 0 V (vs. SHE). However, without an efficient catalyst, this reaction occurred at higher potential, called overpotential. A good HER catalyst is needed to lower the overpotential and hence to …


Real-Time Atomistic Observation Of Structural Phase Transformations In Individual Hafnia Nanorods, Bethany M. Hudak, Sean W. Depner, Gregory R. Waetzig, Anjana Talapatra, Raymundo Arroyave, Sarbajit Banerjee, Beth S. Guiton May 2017

Real-Time Atomistic Observation Of Structural Phase Transformations In Individual Hafnia Nanorods, Bethany M. Hudak, Sean W. Depner, Gregory R. Waetzig, Anjana Talapatra, Raymundo Arroyave, Sarbajit Banerjee, Beth S. Guiton

Chemistry Faculty Publications

High-temperature phases of hafnium dioxide have exceptionally high dielectric constants and large bandgaps, but quenching them to room temperature remains a challenge. Scaling the bulk form to nanocrystals, while successful in stabilizing the tetragonal phase of isomorphous ZrO2, has produced nanorods with a twinned version of the room temperature monoclinic phase in HfO2. Here we use in situ heating in a scanning transmission electron microscope to observe the transformation of an HfO2 nanorod from monoclinic to tetragonal, with a transformation temperature suppressed by over 1000°C from bulk. When the nanorod is annealed, we observe with …


Autonomous Identification And Classification Of Targets Using An Unmanned Aerial System, Taylor Mcdonnell, Tim Mclain May 2017

Autonomous Identification And Classification Of Targets Using An Unmanned Aerial System, Taylor Mcdonnell, Tim Mclain

Journal of Undergraduate Research

Commercial applications of unmanned aerial systems (UAS) are expected to grow significantly in the coming years [1]. Applications of unmanned aerial vehicles in the commercial market include agricultural and infrastructure monitoring, aerial photography, package delivery, fire monitoring, wildlife tracking, and search and rescue operations. One of the purposes of the AUVSI-SUAS competition is to train undergraduates for the growing UAS industry. In this competition a team’s UAS must autonomously identify and locate several targets, which are geometric shapes with a given shape, shape color, letter, letter color, geolocation, and orientation. The focus of this project is to develop the image …


Differentiation Of Ipscs Into Cardiomyocytes Utilizing Extracellular Matrix, Arthur Castleton, Alonzo Cook May 2017

Differentiation Of Ipscs Into Cardiomyocytes Utilizing Extracellular Matrix, Arthur Castleton, Alonzo Cook

Journal of Undergraduate Research

According to the American Heart Association, Ischemic heart disease is the principal cause of death. Many potential therapies are being simultaneously explored and among the most promising is tissue engineering of cardiac scaffolds. In vitro culturing of mature cardiomyocytes has the potential to lay the foundation for products such as cardiac patches for treatment of early stages of Ischemic heart disease or atrial septal defects, and developing entire replacement hearts. However, cardiomyocyte cell culture and experimentation has encountered various difficulties; the inability to proliferate, incomplete maturation, and having a small window of functional contraction. Conversely, iPSCs can partially differentiate into …


Large Body Influence In Internal Wave Generation, Austin Maxwell, Julie Crockett May 2017

Large Body Influence In Internal Wave Generation, Austin Maxwell, Julie Crockett

Journal of Undergraduate Research

Internal waves are three dimensional waves that propagate within a stratified fluid. They are able to propagate in all directions within our atmosphere and the oceans which are both stratified fluids of continuously changing densities. Internal waves are much larger than surface waves, having wavelengths of hundreds of kilometers and amplitudes more than a kilometer in height. Due to their large size they can be difficult to study in nature, and there is still much to be learned about these waves and their impact on the environment. My research has focused on the generation of internal waves by the motion …


Pluripotent Stem Cell (Ipsc) Differentiation To Kidney Phenotype With Conditioned Media Of Rctes, Angela Nakalembe, Dr. Alonzo Cook May 2017

Pluripotent Stem Cell (Ipsc) Differentiation To Kidney Phenotype With Conditioned Media Of Rctes, Angela Nakalembe, Dr. Alonzo Cook

Journal of Undergraduate Research

According to the latest U.S. Renal Data System Annual Data Report, more than 660,000 Americans are currently being treated for kidney failure, also called end stage renal disease (ESRD). The current treatment options, dialysis and kidney transplants, work well in some instances but have disadvantages, such as the inability to perform hormone regulation and potential organ rejection respectively.

The overall aim of our work is to create bioengineered kidneys that will provide alternative solutions to the current treatment methods without any of the drawbacks. New breakthroughs in the biomedical world support the theory that organs can be grown from cultured …


Biosensor System For The Detection Of Endocrine Disrupting Chemicals, Conner Earl, Bradley Bundy May 2017

Biosensor System For The Detection Of Endocrine Disrupting Chemicals, Conner Earl, Bradley Bundy

Journal of Undergraduate Research

Endocrine Disrupting Chemicals (EDCs) present problems worldwide and have been linked to cancer, developmental disorders, and other epigenetic complications. Many of these complications could be mitigated if not eradicated if these chemicals were better characterized and detectable, however an inexpensive, reliable and field deployable sensor for EDCs has yet to be developed. The purpose of this project was to explore the idea of an engineered Cell Free biosensor system that is an economic, viable method for the rapid detection of EDCs.


Portable Food & Water Sanitation By Means Of Energetic Photons, Jordan Argyle, Matthew Memmott May 2017

Portable Food & Water Sanitation By Means Of Energetic Photons, Jordan Argyle, Matthew Memmott

Journal of Undergraduate Research

At least 1 in 10 people across the globe do not have access to clean water.1 The World Health Organization considers food and drink contamination to be “the most widespread health problem in the contemporary world.”2 An estimated 600 million people fall ill from eating contaminated food or drinking contaminated water every year, of which nearly half a million die. Most of those illnesses are caused by pathogens rather than chemical contamination.3


Analysis Of Magnetic Resonance Imaging Of Peripheral Nerve Regeneration, Jaron Lundwall, Alonzo Cook May 2017

Analysis Of Magnetic Resonance Imaging Of Peripheral Nerve Regeneration, Jaron Lundwall, Alonzo Cook

Journal of Undergraduate Research

Due to accident-related neural damage, many people’s lives are impaired or limited in what they can do. Current medical practices are limited at helping distal and proximal nerve stubs regenerate. Many recent research studies have focused on trying to improve this problem by understanding how cut or crushed nerves heal. This study focused on helping these efforts by improving non-invasive analysis techniques of nerve growth. Magnetic Resonance Imaging (MRI) is one possible solution to creating a reliable analysis technique that in the future could be used on humans. We have shown that Magnetic Resonance Imaging can be used without invasive …