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Articles 1 - 30 of 184
Full-Text Articles in Engineering
Development And Validation Of An Absorption Sensor For Time-Resolved Measurements Of Co And Co2, Kyle Thurmond
Development And Validation Of An Absorption Sensor For Time-Resolved Measurements Of Co And Co2, Kyle Thurmond
HIM 1990-2015
A sensor was developed for simultaneous measurements of carbon monoxide and carbon dioxide fluctuations in internal combustion engine exhaust gases. This sensor utilizes low-cost and compact LEDs that emit in the 3-5[micro]m wavelength range which are more appropriate for practical applications than the more traditionally used lasers. An affordable, fast response sensor that can measure these gases has broad application that can lead to more efficient, fuel flexible engines and regulations of harmful emissions. LEDs have a more spectrally broad and diverging emission than lasers which presented many design challenges. The optical design software ZEMAX was utilized to overcome these …
Fracture Toughness Of A Hyperelastic Material During Surgical Cutting, Kevin Smith
Fracture Toughness Of A Hyperelastic Material During Surgical Cutting, Kevin Smith
HIM 1990-2015
Despite being one of the most important organs of vertebrates, the material properties of skin are also one of the most poorly understood. In the field of designing medical devices and surgical tools there are significant advantages to having a model that describes the interaction of forces between a blade tip and skin during surgical cutting. In general, skin can best be described as a composite layer consisting of a viscoelastic dermis with interwoven collagen and elastin fibers beneath a superficial epidermis. The purpose of this research is to study the fracture toughness of porcine skin during practical cutting applications, …
Characterization Of Polyetherimide Under Static, Dynamic, And Multiple Impact Conditions, Bryan Zuanetti
Characterization Of Polyetherimide Under Static, Dynamic, And Multiple Impact Conditions, Bryan Zuanetti
HIM 1990-2015
The application of polymers in robust engineering designs is on the rise due to their excellent mechanical properties such as high fracture toughness, specific strength, durability, as well as, thermal and chemical resistances. Implementation of some advanced polymeric solids is limited due to the lack of available mechanical properties. In order for these materials to endure strenuous engineering designs it is vital to investigate their response in multiple loading rates and conditions. In this thesis, the mechanical response of polyethermide (PEI) is characterized under quasi-static, high strain rate, and multiple impact conditions. Standard tension, torsion, and compression experiments are performed …
A Simplified Approach To Thermomechanical Fatigue And Application To V-Shaped Notches, Thomas Bouchenot
A Simplified Approach To Thermomechanical Fatigue And Application To V-Shaped Notches, Thomas Bouchenot
HIM 1990-2015
A vast array of high value parts in land- and air-based turbomachinery are subjected to non-isothermal cycling in the presence of mechanical loading. Crack initiation, growth and eventual failure more significantly reduce life in these components compared to isothermal conditions. More accurate simulation of the stress and strain evolution at critical locations of components, as well as test specimens, can lead to a more accurate prediction of remaining life to a structural integrity specialists. The focus of this thesis is to characterize the effects of thermomechanical fatigue (TMF) on generic turbomachinery alloy. An expression that can be used to estimate …
Microscopic Surface Textures Created By Interfacial Flow Instabilities, Jing Gu
Microscopic Surface Textures Created By Interfacial Flow Instabilities, Jing Gu
HIM 1990-2015
In nature, microscopic surface textures impact useful function, such as the drag reduction of shark skin (Dean & Bhushan, 2010) and superhydrophobicity of the lotus leaf(Pan, Kota, Mabry, & Tuteja, 2013). In this study, we explore these phenomena by re-creating microscopic surface textures via the method of interfacial flow instability in drying polyvinylidene fluoride (PVDF) acetone solutions. In general, PVDF films can be made using either spin coating or electrospray deposition with various weight concentrations in acetone. In order to study the morphology of the porous structure of PVDF films, wet deposition samples were fabricated by spin coating or near-field …
A Computed Tomography-Based Model Of The Infant Hip Anatomy For Dynamic Finite Element Analysis Of Hip Dysplasia Biomechanics, Kyle Snethen
A Computed Tomography-Based Model Of The Infant Hip Anatomy For Dynamic Finite Element Analysis Of Hip Dysplasia Biomechanics, Kyle Snethen
HIM 1990-2015
Newborns diagnosed with hip dysplasia face severe consequences when treatments fail. The Pavlik harness presents the most common worldwide treatment for correcting this medical hip abnormality in newborns, but becomes increasingly ineffective as subluxation increases. A dynamic finite element analysis on the hip joint would yield results that could provide insight to physicians as to how the Pavlik harness could be optimized to increase its success rate and develop patient-specific treatment plans. The study completes the first step in such an analysis by generating a three-dimensional model of an infant hip joint directly derived from computed tomography imaging in order …
Implementation And Testing Of A Blackbox And A Whitebox Fuzzer For File Compression Routines, Toby Tobkin
Implementation And Testing Of A Blackbox And A Whitebox Fuzzer For File Compression Routines, Toby Tobkin
HIM 1990-2015
Fuzz testing is a software testing technique that has risen to prominence over the past two decades. The unifying feature of all fuzz testers (fuzzers) is their ability to somehow automatically produce random test cases for software. Fuzzers can generally be placed in one of two classes: black-box or white-box. Blackbox fuzzers do not derive information from a program's source or binary in order to restrict the domain of their generated input while white-box fuzzers do. A tradeoff involved in the choice between blackbox and whitebox fuzzing is the rate at which inputs can be produced; since blackbox fuzzers need …
Production, Control And Actuation Of Micron-Sized Particles In A Microfluidic T-Junction, James Wilson
Production, Control And Actuation Of Micron-Sized Particles In A Microfluidic T-Junction, James Wilson
HIM 1990-2015
This research is directed towards understanding the mechanisms associated with the manufacture of solid microspheres less than 100 [micrometers], from liquid droplets with nanosuspensions in a microfluidic T-junction, which are heated downstream of the channel. Preliminary material characterization tests on colloidal suspensions of alumina and copper oxide demonstrate promising temperature dependent viscosity results indicating solidification in the temperature range of 40°C-50°C. The solidification mechanism is referred to as Temperature Induced Forming and is described by polymeric bridges formed between nanoparticles in suspension at elevated temperatures, resulting in a solid structure. The polymer network results from the ionization of alumina at …
Numerical Simulation Of Fracture Of A Nano-Paper Coated E-Glass/Polyester Composite With Thermal Damage, Zachary Graham
Numerical Simulation Of Fracture Of A Nano-Paper Coated E-Glass/Polyester Composite With Thermal Damage, Zachary Graham
HIM 1990-2015
Aerospace research for next-generation travel increasingly focuses on the use of advanced composites to reduce weight and cost while retaining strength. One subset of materials with great potential is based on the combination of resin matrix and glass-fiber reinforcement. This research explores the application of a candidate nanopaper coating with a given composite. Prior research applied a set of given heat fluxes to the top surface of the composite for a set of given periods of time, and subsequently performed a 3-point flexural test to determine the elastic modulus for both the coated and uncoated composite for all of the …
Strategically Minded Dynamic Analysis Of Strategic Flight Bat Maneuvers, Marie Kaspryzk
Strategically Minded Dynamic Analysis Of Strategic Flight Bat Maneuvers, Marie Kaspryzk
HIM 1990-2015
CATD was not only adequate for analyzing the pursuit of erratically moving prey but also worked well when analyzing the pursuit of prey that remained stationary. It cannot be fully concluded that bats utilize the CATD strategy to successfully capture erratically flying prey. The angle remains relatively constant but does not exhibit a zero change in angle as by definition. The large forces experienced by the bat were seen when the bat began to rotate its body about its pitch axis or when the bat made a large turn. Moments were seen specifically when the bat began to bank into …
Application Of Non-Local Approaches For Predicting The Response Of V-Notch Under Thermomechanical Fatigue Loading, Trung Nguyen
Application Of Non-Local Approaches For Predicting The Response Of V-Notch Under Thermomechanical Fatigue Loading, Trung Nguyen
HIM 1990-2015
The topic of this thesis is the construction of a formula to approximate stress-strain responses at notches under thermomechanical fatigue (TMF) loading. The understanding of material behavior of the V-notched component which experiences TMF is important to the mechanical industries where V-notched structures are often utilized. In such applications, it is crucial that the designers be able to predict the material behavior; therefore, the purpose of this research is to examine and to model the precise effects a stress concentration will have on a specimen made of a generic Ni-base superalloy. The effects of non-isothermal loading will be studied, and …
Commuting In Portland, Oregon: The Advantages Of Living Within A Transit Oriented Development Community Compared To Traditional Suburban Development By Comparing Environmental, Economic And Health Factors, Kyle Simpson
HIM 1990-2015
Transportation is a function that affects nearly all life decisions, but is often not given much thought by the average individual throughout their daily routines. Most of this complacency streams from the mainstream development patterns in the United States that have changed little from the end of World War II. During the immediate post-war years a perfect mix for suburban living came together: the mass production of automobiles, guaranteed mortgages from the federal government through the G.I. Bill, and in 1956 the passage of the National Interstate and Defense Highways Act. These factors, along with the dominate social paradigm that …
High Flux Isolated Attosecond Pulse Generation, Yi Wu
High Flux Isolated Attosecond Pulse Generation, Yi Wu
Electronic Theses and Dissertations
This thesis outlines the high intensity tabletop attosecond extreme ultraviolet laser source at the Institute for the Frontier of Attosecond Science and Technology Laboratory. First, a unique Ti:Sapphire chirped pulse amplifier laser system that delivers 14 fs pulses with 300 mJ energy at a 10 Hz repetition rate was designed and built. The broadband spectrum extending from 700 nm to 900 nm was obtained by seeding a two stage Ti:Sapphire chirped pulse power amplifier with mJ-level white light pulses from a gas filled hollow core fiber. It is the highest energy level ever achieved by a broadband pulse in a …
Understanding The Capabilities And Limitations Of Advanced Interactive M&S: A Cricothyroidotomy Simulation Case Study, Lillian Campbell-Wynn
Understanding The Capabilities And Limitations Of Advanced Interactive M&S: A Cricothyroidotomy Simulation Case Study, Lillian Campbell-Wynn
Electronic Theses and Dissertations
Simulation for surgical education and training is increasingly perceived as a valuable contribution to traditional teaching methods providing a structured learning experience. Surgical simulations allow surgeons to practice tactics, techniques and procedures numerous times without the cost, limitations and ethical problems of using cadaver-based models. The goal of this research is to advance the use of modeling and simulation in support of emergency medical training. This research explores questions identified through a case study of two different modeling and simulation techniques – virtual reality and mannequins - in the support of combat emergency medical education and training. To reduce the …
Design Optimization Of Llc Topology And Phase Skipping Control Of Three Phase Inverter For Pv Applications, Utsav Somani
Design Optimization Of Llc Topology And Phase Skipping Control Of Three Phase Inverter For Pv Applications, Utsav Somani
Electronic Theses and Dissertations
The world is heading towards an energy crisis and desperate efforts are being made to find an alternative, reliable and clean source of energy. Solar Energy is one of the most clean and reliable source of renewable energy on earth. Conventionally, extraction of solar power for electricity generation was limited to PV farms, however lately Distributed Generation form of Solar Power has emerged in the form of residential and commercial Grid Tied Micro-Inverters. Grid Tied Micro-Inverters are costly when compared to their string type counterparts because one inverter module is required for every single or every two PV panels whereas …
First Principle Studies Of Cu-Carbon Nanotube Hybrid Structures With Emphasis On The Electronic Structures And The Transport Properties, Chengyu Yang
Electronic Theses and Dissertations
Carbon nanotubes have been regarded as ideal building blocks for nanoelectronics and multifunctional nanocomposites due to their exceptional strength, stiffness, flexibility, as well as their excellent electrical properties. However, carbon nanotube itself has limitations to fulfill the practical application needs: 1) an individual carbon nanotube has a low density of states at the Fermi level, and thus its conductivity is only comparable to moderate metals but lower than that of copper. 2) Metallic and semiconducting nanotubes are inherently mixed together from the synthesis, and the selection/separation is very difficult with very low efficiency. 3) Carbon nanotubes alone cannot be used …
Routing, Localization And Positioning Protocols For Wireless Sensor And Actor Networks, Mustafa Akbas
Routing, Localization And Positioning Protocols For Wireless Sensor And Actor Networks, Mustafa Akbas
Electronic Theses and Dissertations
Wireless sensor and actor networks (WSANs) are distributed systems of sensor nodes and actors that are interconnected over the wireless medium. Sensor nodes collect information about the physical world and transmit the data to actors by using one-hop or multi-hop communications. Actors collect information from the sensor nodes, process the information, take decisions and react to the events. This dissertation presents contributions to the methods of routing, localization and positioning in WSANs for practical applications. We first propose a routing protocol with service differentiation for WSANs with stationary nodes. In this setting, we also adapt a sports ranking algorithm to …
The Study Of Photo-Reduction Of Cerium Oxide Nanoparticles In Presence Of Dextran: An Attempt In Understanding The Functionality Of The System, Swetha Barkam
Electronic Theses and Dissertations
Malignant melanoma cancer is the sixth common cancer diagnosed in the United States. Surgery, chemotherapy and radiation are some of the successful techniques in killing tumor cells. However, in these techniques, it is not easy to distinguish tumor cells from the healthy once which inadvertently get exposed to chemical agent/radiation. Therefore it is required to develop an anticancer agent which selectively kills the cancer cells, while still protecting the normal tissues. In our preliminary work, we have shown that Dextran (1000Da) coated Cerium oxide nanoparticles (Dex-CNPs) selectively kills the cancer cells (50% killing at a concentration of 150μM) without inducing …
Influence Of Task-Role Mental Models On Human Interpretation Of Robot Motion Behavior, Scott Ososky
Influence Of Task-Role Mental Models On Human Interpretation Of Robot Motion Behavior, Scott Ososky
Electronic Theses and Dissertations
The transition in robotics from tools to teammates has begun. However, the benefit autonomous robots provide will be diminished if human teammates misinterpret robot behaviors. Applying mental model theory as the organizing framework for human understanding of robots, the current empirical study examined the influence of task-role mental models of robots on the interpretation of robot motion behaviors, and the resulting impact on subjective ratings of robots. Observers (N = 120) were exposed to robot behaviors that were either congruent or incongruent with their task-role mental model, by experimental manipulation of preparatory robot task-role information to influence mental models (i.e., …
The Effects Of Assumption On Subspace Identification Using Simulation And Experiment Data, Yoonhwak Kim
The Effects Of Assumption On Subspace Identification Using Simulation And Experiment Data, Yoonhwak Kim
Electronic Theses and Dissertations
In the modern dynamic engineering field, experimental dynamics is an important area of study. This area includes structural dynamics, structural control, and structural health monitoring. In experimental dynamics, methods to obtain measured data have seen a great influx of research efforts to develop an accurate and reliable experimental analysis result. A technical challenge is the procurement of informative data that exhibits the desired system information. In many cases, the number of sensors is limited by cost and difficulty of data archive. Furthermore, some informative data has technical difficulty when measuring input force and, even if obtaining the desired data were …
Optically Induced Forces In Scanning Probe Microscopy, Dana Kohlgraf-Owens
Optically Induced Forces In Scanning Probe Microscopy, Dana Kohlgraf-Owens
Electronic Theses and Dissertations
The focus of this dissertation is the study of measuring light not by energy transfer as is done with a standard photodetector such as a photographic film or charged coupled device, but rather by the forces which the light exerts on matter. In this manner we are able to replace or complement standard photodetector-based light detection techniques. One key attribute of force detection is that it permits the measurement of light over a very large range of frequencies including those which are difficult to access with standard photodetectors, such as the far IR and THz. The dissertation addresses the specific …
Nano-Particles In Multi-Scale Composites And Ballistic Applications, Jason Gibson
Nano-Particles In Multi-Scale Composites And Ballistic Applications, Jason Gibson
Electronic Theses and Dissertations
Carbon nanotubes, graphene and nano sized core shell rubber particles have all been extensively researched for their capability to improve mechanical properties of thermoset resins. However, there has been a lack of research on their evaluation for energy absorption in high velocity impact scenarios, and the fundamental mechanics of their failure mechanisms during highly dynamic stress transfer through the matrix. This fundamental research is essential for laying the foundation for improvement in ballistic performance in composite armor. In hard armor applications, energy absorption is largely accomplished through delamination between plies of the composite laminate. This energy absorption is accomplished through …
Polymer Optical Fibers For Luminescent Solar Concentration, Esmaeil Banaei
Polymer Optical Fibers For Luminescent Solar Concentration, Esmaeil Banaei
Electronic Theses and Dissertations
Luminescent solar concentrators (LSC’s) are promising candidates for reducing the cost of solar power generation. Conventional LSC’s are slab waveguides coated or doped with luminescence materials for absorption and guiding of light to the slab edges in order to convert optical energy into electricity via attached photovoltaic (PV) cells. Exploiting the advantages of optical fiber production, a fiber LSC (FLSC) is presented in this thesis, in which the waveguide is a polymeric optical fiber. A hybrid fiber structure is proposed for an efficient two-stage concentration of incident light, first into a small doped core using a cylindrical micro-lens that extends …
Heat And Fluid Flow Characterization Of A Single-Hole-Per-Row Impingement Channel At Multiple Impingement Heights, Roberto Claretti
Heat And Fluid Flow Characterization Of A Single-Hole-Per-Row Impingement Channel At Multiple Impingement Heights, Roberto Claretti
Electronic Theses and Dissertations
The present work studies the relationship between target and sidewall surfaces of a multirow, narrow impingement channel at various jet heights with one impingement hole per row. Temperature sensitive paint and constant flux heaters are used to gather heat transfer data on the target and side walls. Jet-to-target distance is set to 1, 2, 3, 5, 7 and 9 jet diameters. The channel width is 4 jet diameters and the jet stream wise spacing is 5 jet diameters. All cases were run at Reynolds numbers ranging from 5,000 to 30,000. Pressure data is also gathered and used to calculate the …
Bio-Inspired Cooperative Optimal Trajectory Planning For Autonomous Vehicles, Charles Remeikas
Bio-Inspired Cooperative Optimal Trajectory Planning For Autonomous Vehicles, Charles Remeikas
Electronic Theses and Dissertations
With the recent trend for systems to be more and more autonomous, there is a growing need for cooperative trajectory planning. Applications that can be considered as cooperative systems such as surveying, formation flight, and traffic control need a method that can rapidly produce trajectories while considering all of the constraints on the system. Currently most of the existing methods to handle cooperative control are based around either simple dynamics and/or on the assumption that all vehicles have homogeneous properties. In reality, typical autonomous systems will have heterogeneous, nonlinear dynamics while also being subject to extreme constraints on certain state …
Integrated Data Fusion And Mining (Idfm) Technique For Monitoring Water Quality In Large And Small Lakes, Benjamin Vannah
Integrated Data Fusion And Mining (Idfm) Technique For Monitoring Water Quality In Large And Small Lakes, Benjamin Vannah
Electronic Theses and Dissertations
Monitoring water quality on a near-real-time basis to address water resources management and public health concerns in coupled natural systems and the built environment is by no means an easy task. Furthermore, this emerging societal challenge will continue to grow, due to the ever-increasing anthropogenic impacts upon surface waters. For example, urban growth and agricultural operations have led to an influx of nutrients into surface waters stimulating harmful algal bloom formation, and stormwater runoff from urban areas contributes to the accumulation of total organic carbon (TOC) in surface waters. TOC in surface waters is a known precursor of disinfection byproducts …
Analysis And Design Optimization Of Multiphase Converter, Kejiu Zhang
Analysis And Design Optimization Of Multiphase Converter, Kejiu Zhang
Electronic Theses and Dissertations
Future microprocessors pose many challenges to the power conversion techniques. Multiphase synchronous buck converters have been widely used in high current low voltage microprocessor application. Design optimization needs to be carefully carried out with pushing the envelope specification and ever increasing concentration towards power saving features. In this work, attention has been focused on dynamic aspects of multiphase synchronous buck design. The power related issues and optimizations have been comprehensively investigated in this paper. In the first chapter, multiphase DC-DC conversion is presented with background application. Adaptive voltage positioning and various nonlinear control schemes are evaluated. Design optimization are presented …
Self-Assembled Two-Component Organic Tubes: Structures And Applications, Wenlang Liang
Self-Assembled Two-Component Organic Tubes: Structures And Applications, Wenlang Liang
Electronic Theses and Dissertations
Bile acids are physiologically important metabolites, which are synthesized in liver as the end products of cholesterol metabolism and then secreted into the intestines. They play a critical role in the digestion and absorption of fats and fat-soluble vitamins through emulsifications. The amphipathic and chiral nature of bile acids makes their unique building blocks for assembling supramolecular structures including vesicles, fibers, ribbons and hollow tubes. Lithocholic acid (LCA) is a secondary bile acid. Our studies show LCA can selfassemble into helical tubes in aqueous solution by the linear aggregation and fusion of vesicles. The objective of this dissertation is to …
Vision-Based Sensing And Optimal Control For Low-Cost And Small Satellite Platforms, Bradley Sease
Vision-Based Sensing And Optimal Control For Low-Cost And Small Satellite Platforms, Bradley Sease
Electronic Theses and Dissertations
Current trends in spacecraft are leading to smaller, more inexpensive options whenever possible. This shift has been primarily pursued for the opportunity to open a new frontier for technologies with a small financial obligation. Limited power, processing, pointing, and communication capabilities are all common issues which must be considered when miniaturizing systems and implementing low-cost components. This thesis addresses some of these concerns by applying two methods, in attitude estimation and control. Additionally, these methods are not restricted to only small, inexpensive satellites, but offer a benefit to large-scale spacecraft as well. First, star cameras are examined for the tendency …
Success In Technology Organizations, Joseph Bass
Success In Technology Organizations, Joseph Bass
Electronic Theses and Dissertations
In today’s economic environment, it is advantageous for technology organizations to be cognizant of prevalent influences on success and failure and to incorporate this knowledge into their business and innovation strategies. Technology organizations were defined within this research as those in the business of created competence which is expressed in terms of entities consisting of devices, procedures, and acquired human skills (Clarke, 2005). Although, no organization contains the ideal mix of culture and ideological emphases, some have amassed impressive track records of great success. A literature review was used to identify factors relevant within similar contexts such as influences on …