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Theses and Dissertations

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Full-Text Articles in Engineering

Initial Implementation And Testing Of A Tightly-Coupled Imu/Pseudolite System, James E. C. Kawecki Mar 2015

Initial Implementation And Testing Of A Tightly-Coupled Imu/Pseudolite System, James E. C. Kawecki

Theses and Dissertations

Currently, the 746th Test Squadrons (746th TS) Central Inertial and GPS Test Facility (CIGTF) operates one of the most accurate truth reference systems, called the CIGTF Reference System (CRS). CIGTF will be replacing the CRS with a new references system called UHARS (Ultra High Accuracy Reference System). UHARS will differ from CRS by adding the ability to use a non-GPS pseudolite system, as a new measurement source. This research effort describes the design of the extended Kalman filter which is developed in AFIT's SPIDER filter framework which implements a tightly-coupled pseudolite/INS filter.

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Git As An Encrypted Distributed Version Control System, Russell G. Shirey Mar 2015

Git As An Encrypted Distributed Version Control System, Russell G. Shirey

Theses and Dissertations

This thesis develops and presents a secure Git implementation, Git Virtual Vault (GV2), for users of Git to work on sensitive projects with repositories located in unsecure distributed environments, such as in cloud computing. This scenario is common within the Department of Defense, as much work is of a sensitive nature. In order to provide security to Git, additional functionality is added for confidentiality and integrity protection. This thesis examines existing Git encryption implementations and baselines their performance compared to unencrypted Git. Real-world Git repositories are examined to characterize typical Git usage and determine if the existing Git encryption implementations …

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Robust Models For Operator Workload Estimation, Andrew M. Smith Mar 2015

Robust Models For Operator Workload Estimation, Andrew M. Smith

Theses and Dissertations

When human-machine system operators are overwhelmed, judicious employment of automation can be beneficial. Ideally, a system which can accurately estimate current operator workload can make better choices when to employ automation. Supervised machine learning models can be trained to estimate workload in real time from operator physiological data. Unfortunately, estimating operator workload using trained models is limited: using a model trained in one context can yield poor estimation of workload in another. This research examines the utility of three algorithms (linear regression, regression trees, and Artificial Neural Networks) in terms of cross-application workload prediction. The study is conducted for a …

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Characterizing Multiple Wireless Sensor Networks For Large-Scale Radio Tomography, Tan Van Mar 2015

Characterizing Multiple Wireless Sensor Networks For Large-Scale Radio Tomography, Tan Van

Theses and Dissertations

Radio Tomographic Imaging (RTI) is an emerging Device-Free Passive Localization (DFPL) technology that uses a collection of cheap wireless transceivers to form a Wireless Sensor Network (WSN). Unlike device-based active localization, DFPL does not require a target of interest to be wearing any kind of device. The basic concept of RTI utilizes the changes in Received Signal Strength (RSS) between the links of each transceiver to create an attenuation image of the area. This image can then be used for target detection, tracking, and localization. Each transceiver in the WSN must transmit sequentially to prevent collisions. This is not a …

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Expected Position Error For An Onboard Satellite Gps Receiver, Anthony S. Williams Mar 2015

Expected Position Error For An Onboard Satellite Gps Receiver, Anthony S. Williams

Theses and Dissertations

The Global Positioning System (GPS) constellation provides ranging information that delivers inexpensive, high precision positioning for terrestrial users. Satellites in Low Earth Orbit (LEO) can use an onboard GPS receiver resulting in meter-level navigation solution accuracy. There are limitations to using GPS for positioning for satellites above LEO. The number of GPS satellites who's signal can be received decreases as the receivers altitude approaches that of the GPS constellation. Above the GPS constellation, the available GPS signals for ranging will originate from satellites on the opposite side of Earth. This research calculates the available GPS signals to the receiver and …

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The Brazilian Air Force Uniform Distribution Process: Using Lean Thinking, Statistical Process Control And Theory Of Constraints To Address Improvement Opportunities, Luciano A. Dos Santos Mar 2015

The Brazilian Air Force Uniform Distribution Process: Using Lean Thinking, Statistical Process Control And Theory Of Constraints To Address Improvement Opportunities, Luciano A. Dos Santos

Theses and Dissertations

In the Brazilian Air Force, all enlisted Soldiers and Corporals (corresponding to USAF ranks from Airman Basic to Senior Airman) are entitled to receive their uniforms from their assigned, respective organizations, free of charge. An important portion of the uniform s distribution process is accomplished by the Brazilian Air Force Intendancy Central Depot (ICD). This organization carries the uniform inventory and performs the selection and distribution activities, following the guidance of the Sub-directorate of Supply. ICD process performance data for the peak distribution seasons of 2012 and 2013 was collected and analyzed. Several indications of inefficiencies became apparent, exemplified by …

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Non-Rated Air Force Line Officer Attrition Rates Using Survival Analysis, Jill A. Schofield Mar 2015

Non-Rated Air Force Line Officer Attrition Rates Using Survival Analysis, Jill A. Schofield

Theses and Dissertations

The Air Force structures its workforce around rank structure and work specialty codes (Air Force Specialty Codes (AFSCs)). The challenge is to grow and manage personnel to fill a variety of skill sets at a variety of ranks over a 20-30 year planning horizon. To ensure that the missions are accomplished while adhering to congressionally-mandated force allocations, the Air Force is continually attempting to \right size its force by maintaining the correct balance of personnel in each career field. The Air Force conducts its force structure management responsibility by comparing historical attrition rates to current manpower requirements for each AFSC …

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Active Duty C-17 Aircraft Commander Fuel Efficiency Metrics And Goal Evaluation, Michael J. Schumacher Mar 2015

Active Duty C-17 Aircraft Commander Fuel Efficiency Metrics And Goal Evaluation, Michael J. Schumacher

Theses and Dissertations

As the largest consumer of fuel in the Department of Defense, the Air Force continually looks for new ways to advocate aircraft fuel efficiency. Optimal metrics and goals are essential components to encourage efficient flying. This research examined two metrics through quantitative statistical and qualitative criteria analysis, picked the most effective metric, and utilized Goal Setting Theory (GST) to couple the metric with an attainable goal aimed at making Aircraft Commander's (AC's) more fuel efficient. The first metric, M1Cargo Adjusted, uses current sortie planning factors and adjusts these for payload. The second metric, M2Regression, uses regression analysis based on flight …

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Statistical Observations Of Positioning, Navigation, And Timing In A Combat Simulation, Matthew G. Thomas Mar 2015

Statistical Observations Of Positioning, Navigation, And Timing In A Combat Simulation, Matthew G. Thomas

Theses and Dissertations

The Global Positioning System (GPS) has become an important asset in the lives of civilians and defense organizations. GPS uses include positioning, navigation, timing, as well as many other daily applications. With such dependence, protection against attacks on the system is paramount to continue its effectiveness. Attacks on its signal is the easiest way for enemies to degrade and harm not only everyday functioning for civilians, but a nation's defense as well. Jamming interference and spoofing are the two most frequent attacks on GPS signals. Could these two attacks cause significant effect on military operations? We use a System Effectiveness …

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Test And Evaluation Of Ultrasonic Additive Manufacturing (Uam) For A Large Aircraft Maintenance Shelter (Lams) Baseplate, Daniel H. Gartland Mar 2015

Test And Evaluation Of Ultrasonic Additive Manufacturing (Uam) For A Large Aircraft Maintenance Shelter (Lams) Baseplate, Daniel H. Gartland

Theses and Dissertations

Additive manufacturing is an exciting new manufacturing technology that could have application to Air Force Civil Engineer (CE) operations. This research replicates a Large Area Maintenance Shelter (LAMS) baseplate design for ultrasonic additive manufacturing (UAM). Due to production problems the test section was not built as designed. Instead, a smaller block of material was submitted for evaluation. After the UAM build, ultrasonic inspection was conducted to identify anomalies in the test piece. The results of this proof of concept study indicate that UAM is not yet ready for CE expeditionary applications requiring a high degree of mechanical strength. The machine …

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The Impact Of United States Investment For Civil Infrastructure In Developing Countries, Joel N. Hansen Mar 2015

The Impact Of United States Investment For Civil Infrastructure In Developing Countries, Joel N. Hansen

Theses and Dissertations

U.S. foreign assistance is used to support regional interests and to address the economic and social needs of host nation (HN) citizens. Within the Department of Defense (DoD), military exercises implement humanitarian and civic assistance (HCA) activities in developing nations as one method of accomplishing the U.S. foreign assistance objectives. To account for the impact of civil infrastructure projects on HN citizens, this research incorporated survey data collected during a DoD-sponsored exercise in Belize to test the expectancy disconfirmation model of citizen satisfaction and analyze the impact of constructing HCA projects on citizen satisfaction with HN government services. The research …

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Effect Of Malathion On The Microbial Ecology Of Activated Sludge, Seth K. Martin Mar 2015

Effect Of Malathion On The Microbial Ecology Of Activated Sludge, Seth K. Martin

Theses and Dissertations

Decontamination activities may cause the release of contaminated washwater into the wastewater that eventually flows into a wastewater treatment facility. This raises concerns about the effect of chemical warfare agents (CWAs) on the microbial consortia that are responsible for cleaning the wastewater. This study investigated the impact of malathion on the microbial ecology of laboratory scale activated sludge communities. The Simpson Reciprocal Index decreased for three bioreactors operated in the absence of malathion, which showed that the microbial assemblage became less diverse during the course of the study. The species identified in the bioreactors belonged to well-known groups of heterotrophic …

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A Delphi Study Using Value-Focused Thinking For United States Air Force Mission Dependency Index Values, Matthew J. Nichols Mar 2015

A Delphi Study Using Value-Focused Thinking For United States Air Force Mission Dependency Index Values, Matthew J. Nichols

Theses and Dissertations

Recently, the Air Force Civil Engineer Center (AFCEC) identified that the Mission Dependency Index (MDI) had issues with reflecting the criticality of some mission sets. The MDI is a constructed value assigned to assets that reflects the consequence of failure. The primary mission sets having MDI issues were non-flightline assets. The current Air Force MDI metric relies on data collected using the Naval Facilities Engineering Command (NAVFAC) methodology and adapts the data by using facility categorization codes. The result is a method that compares alternatives to each other to develop an individual asset's MDI value. As a corrective measure to …

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Overall Effectiveness Measurement At Engine Temperatures With Reactive Film Cooling And Surface Curvature, Andrew J. Lynch Mar 2015

Overall Effectiveness Measurement At Engine Temperatures With Reactive Film Cooling And Surface Curvature, Andrew J. Lynch

Theses and Dissertations

The thesis presented here details the design, construction and initial testing of rig for use with high temperature film cooling testing. The film cooling rig was supplied with hot mainstream gas from a well-stirred reactor operating on a propane/air mixture capable of multiple equivalence ratios. The Hastelloy test plates contained an internal cooling channel to allow for overall effectiveness measurements. Thermocouples on both the freestream and internal surfaces of the test plate provided temperature differences for heat flux calculations. The test plates had a quarter circle leading edge with a tapered trailing edge to provide surface curvature for the film …

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Characterization And Modeling Of A Control Moment Gyroscope, Dylan R. Penn Mar 2015

Characterization And Modeling Of A Control Moment Gyroscope, Dylan R. Penn

Theses and Dissertations

The Air Force Research Laboratory (AFRL) is developing a spacecraft simulator that uses Control Moment Gyroscopes (CMGs). Prior to the research herein, the Air Force Institute of Technology (AFIT) designed and built six laboratory-rated CMGs for use on the AFRL spacecraft simulator. The main contributions of this research are in the testing and modeling of a single CMG. Designing, building, and operating spacecraft simulators is time consuming and expensive, but less so than tests with on-orbit spacecraft. Reductions in cost and schedule can be realized by investing in modeling the spacecraft simulator and payload before testing. A model of the …

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Optimal Recovery Trajectories For Automatic Ground Collision Avoidance Systems (Auto Gcas), Angela W. Suplisson Mar 2015

Optimal Recovery Trajectories For Automatic Ground Collision Avoidance Systems (Auto Gcas), Angela W. Suplisson

Theses and Dissertations

The USAF's F-16 Automatic Ground Collision Avoidance System (Auto GCAS) uses a single pre-planned roll to wings- level and 5-g pull-up to meet the operational requirements of being both aggressive and timely, meaning that extremely agile avoidance maneuvers will be executed at the last second to avoid the ground. There currently exists no similar Auto GCAS for manned military heavy' aircraft with lower climb performance such as transport, tanker, or bomber aircraft. This research proposes a new optimal control approach to the ground collision avoidance problem for heavy aircraft by mapping the aggressive and timely requirements of the automatic recovery …

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Experimental Magnetohydrodynamic Energy Extraction From A Pulsed Detonation, Kaz I. Teope Mar 2015

Experimental Magnetohydrodynamic Energy Extraction From A Pulsed Detonation, Kaz I. Teope

Theses and Dissertations

The high MWatt power available in a fuel-fed detonation wave, which contains combustion ions in the trailing gas, provides an opportunity for external power extraction via electromagnetically forced charged particle drift. Sets of experiments were accomplished using a pulsed detonation tube, extracting power across a load resistor in an electrical circuit with an applied electric or magnetic field to determine what magnitude of gas conductivity and power extraction could be attained from an unseeded or seeded pulsed detonation driven combustion. Due to the low magnetic field strength, even with flow seeding, the power extracted in this research was not enough …

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Fatigue Behavior Of Im7/Bmi 5250-4 Composite At Room And Elevated Temperatures, James T. Tipton Mar 2015

Fatigue Behavior Of Im7/Bmi 5250-4 Composite At Room And Elevated Temperatures, James T. Tipton

Theses and Dissertations

The tension-tension fatigue and tension-compression fatigue behaviors of the IM7/BMI 5250-4 composite were investigated. The tension-tension fatigue of the composite with 0/90 and ±45 fiber orientations was studied at 23, 170, and 190°C. The tension-compression fatigue of the composite with 0/90 fiber orientation was examined at 23°C. The tensile and compressive properties of the composite were also evaluated at room and elevated temperatures for both 0/90 and ±45 fiber orientations. Elevated temperature had little effect on the tensile properties of the 0/90 fiber orientation, but strongly influenced the ±45 tensile properties as well as the compressive properties of both fiber …

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Mechanical Testing Of Ultra-High Temperature Ceramics At 1500°C In Air -Development Of An Experimental Facility And Test Method, Sheena L. Winder Mar 2015

Mechanical Testing Of Ultra-High Temperature Ceramics At 1500°C In Air -Development Of An Experimental Facility And Test Method, Sheena L. Winder

Theses and Dissertations

With a melting point in excess of 3000°C and a high density, ultra-high temperature ceramics (UHTCs) are a candidate material for hypersonic flight vehicles, atmospheric re-entry vehicles, and rocket propulsion systems. When ceramics are under consideration as a structural material, creep is an important design criterion and a life-limiting condition. However, the characterization of mechanical behavior at temperatures in excess of 1300°C has many challenges to overcome. Of utmost importance is the selection of materials for test fixtures. Materials selected must maintain their structural integrity, not cause chemical degradation of the test material, and not interfere with the acquisition of …

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Load Frequency Control Of Battery Based Energy Storages, Neeru Saini Mar 2015

Load Frequency Control Of Battery Based Energy Storages, Neeru Saini

Theses and Dissertations

This work is the study of potential applications of battery-based energy storages in the power system so that the performance can be improved. The research is focused on the case where batteries are installed at the load side. Such a battery works like an energy buffer between power system and a load. It is possible to control the battery charging time based on the status of the power system operation and the state of charger of the battery so that the power flow in the power system can become more stable. The strategy of load frequency control (LFC) was investigated …

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Raman Spectroscopy As A Tool For Single Circulating Tumor Cell (Ctc) Detection And Imaging, Zeid A. Nima Mar 2015

Raman Spectroscopy As A Tool For Single Circulating Tumor Cell (Ctc) Detection And Imaging, Zeid A. Nima

Theses and Dissertations

Breast cancer is the most common type of cancers in the United States. It is imperative that a quick and reliable method for the early detection of circulating tumor cells (CTCs) be identified and tested. In this research several new detection and imaging techniques based on using Raman spectroscopy have been invented. Raman active nano-complex agents based on single-walled carbon nanotubes (SWCNTs) were prepared and used for the swift and specific detection of breast cancer cells. SWCNTs are functionalized with the anti-epithelial cell adhesion molecule (anti-EpCAM) antibody, were able to detect CTCs within 30 min and discriminate few CTCs among …

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Modeling And Simulation Of Evacuation Plan For Hancock Stadium, Nirmal Neranjan Weerasekara Mar 2015

Modeling And Simulation Of Evacuation Plan For Hancock Stadium, Nirmal Neranjan Weerasekara

Theses and Dissertations

The goal of this study is to use Modeling and Simulation of Evacuation Plan (MSEP) to support management to execute proper evacuation plan in case of emergency at Hancock Stadium in Illinois State University. Analyses of the research literature and evacuation scenarios are used to build a simulation system that will connect a description of emergency and evacuation situation with its context. It shows how an evacuation plan actually functions. The results of the study will help safety managers to understand the current situations of evacuation according to the specific simulation scenarios. The evacuation simulation is categorized according to the …

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Event-Based Hydrologic Model Calibration Using Nexrad In A Data-Poor Region Of Southern New Jersey, Christopher Siegel Mar 2015

Event-Based Hydrologic Model Calibration Using Nexrad In A Data-Poor Region Of Southern New Jersey, Christopher Siegel

Theses and Dissertations

Proper calibration of hydrologic models requires both reliable observed stream flow and precipitation data. Southern New Jersey has a notable lack of observed precipitation data, in particular, at the event scale; therefore model calibration represents a significant challenge. From a design standpoint this has not been a major concern as hydrologic models have been driven using design storms and are not calibrated. However, the need for research and impact analyses in the face of climate change (changes in extreme precipitation and sea-level rise in particular) and expected population growth in the region requires calibrated models, and reliable observed precipitation data …

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Verification Of The Dissipated Energy Based Fatigue Model Using Field Data, Thomas Redles Mar 2015

Verification Of The Dissipated Energy Based Fatigue Model Using Field Data, Thomas Redles

Theses and Dissertations

Damage can be limited to the top layer in perpetual pavements through the use of a very thick surface layer or a binder-rich intermediate layer. To achieve this goal, tensile strains at the bottom of the top hot-mix asphalt (HMA) layer must be limited to below a certain value known as the fatigue endurance limit (FEL). In this thesis, a method for estimating the allowable strain in the asphalt layers of flexible airfield pavements is proposed based on the concept that HMA fatigue failure is associated with a significant reduction in HMA layer modulus, usually taken as 50 percent. Falling …

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Advancing Biomechanical Research Through A Camelid Model Of The Human Lumbar Spine, Dean K. Stolworthy Mar 2015

Advancing Biomechanical Research Through A Camelid Model Of The Human Lumbar Spine, Dean K. Stolworthy

Theses and Dissertations

The increasing incidence of disc degeneration and its correlation with lower back pain is an alarming trend in modern society. The research of intervertebral disc degeneration and low back pain would greatly benefit from additional methods to study its etiology and possible treatment methods. A large animal model that maintains the biological and mechanical environment that is most similar to the human lumbar spine could provide substantial improvements in understanding and resolving the problem of intervertebral disc related low back pain.This dissertation presents my doctoral work of investigating the potential for the camelid cervical spine to serve as a suitable …

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Detecting And Tracking Moving Objects From A Small Unmanned Air Vehicle, Patrick Defranco Mar 2015

Detecting And Tracking Moving Objects From A Small Unmanned Air Vehicle, Patrick Defranco

Theses and Dissertations

As the market for unmanned air vehicles (UAVs) rapidly expands, the need for algorithmsthat improve the capabilities of those vehicles is also growing. One valuable capability for UAVsis that of persistent tracking—the ability to find and track another moving object, usually on theground, from an aerial platform. This thesis presents a method for tracking multiple ground targetsfrom an airborne camera. Moving objects on the ground are detected by using frame-to-frameregistration. The detected objects are then tracked using the newly developed recursive RANSACalgorithm. Much video tracking work has focused on using appearance-based processing for tracking,with some approaches using dynamic trackers such …

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Vision Based Multiple Target Tracking Using Recursive Ransac, Kyle Ingersoll Mar 2015

Vision Based Multiple Target Tracking Using Recursive Ransac, Kyle Ingersoll

Theses and Dissertations

In this thesis, the Recursive-Random Sample Consensus (R-RANSAC) multiple target tracking (MTT) algorithm is further developed and applied to video taken from static platforms. Development of R-RANSAC is primarily focused in three areas: data association, the ability to track maneuvering objects, and track management. The probabilistic data association (PDA) filter performs very well in the R-RANSAC framework and adds minimal computation cost over less sophisticated methods. The interacting multiple models (IMM) filter as well as higher-order linear models are incorporated into R-RANSAC to improve tracking of highly maneuverable targets. An effective track labeling system, a more intuitive track merging criteria, …

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Hydrologic Data Sharing Using Open Source Software And Low-Cost Electronics, Jeffrey Michael Sadler Mar 2015

Hydrologic Data Sharing Using Open Source Software And Low-Cost Electronics, Jeffrey Michael Sadler

Theses and Dissertations

While it is generally accepted that environmental data are critical to understanding environmental phenomena, there are yet improvements to be made in their consistent collection, curation, and sharing. This thesis describes two research efforts to improve two different aspects of hydrologic data collection and management. First described is a recipe for the design, development, and deployment of a low-cost environmental data logging and transmission system for environmental sensors and its connection to an open source data-sharing network. The hardware is built using several low-cost, open-source, mass-produced components. The system automatically ingests data into HydroServer, a standards-based server in the open …

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Investigation Of Laboratory Test Procedures For Assessing The Structural Capacity Of Geogrid-Reinforced Aggregate Base Materials, Jaren Tolman Knighton Mar 2015

Investigation Of Laboratory Test Procedures For Assessing The Structural Capacity Of Geogrid-Reinforced Aggregate Base Materials, Jaren Tolman Knighton

Theses and Dissertations

The modulus of aggregate base layers in pavement structures can potentially be increased through the use of geogrid. However, methods for determining how much structural benefit can be expected from a given geogrid product have not been standardized. A laboratory testing protocol is therefore needed to enable evaluation, in terms of modulus or California bearing ratio (CBR), for example, of the degree of improvement that may be achieved by a given geogrid. Consequently, the objective of this research was to identify a laboratory test method that can be used to quantify improvements in structural capacity of aggregate base materials reinforced …

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Electrical And Physical Property Characterization Of Single Walled Carbon Nanotube Ink For Flexible Printed Electronics, Kristian E. Warner Jr. Mar 2015

Electrical And Physical Property Characterization Of Single Walled Carbon Nanotube Ink For Flexible Printed Electronics, Kristian E. Warner Jr.

Theses and Dissertations

This research presents a method of characterizing single-walled carbon nanotube (SWCNT) ink. This research also examines the results of our characterization efforts. First, the process of ink jet printing SWCNT ink onto organic and inorganic substrates is discussed. Next, the tests for measuring sheet resistance, conductance, inductance, adherence, thickness, roll-off, and S-parameters of the ink are described. Results and findings of the research are presented. The SWCNT ink created by Brewer Science © is shown to be an effective material for additive manufacturing using an aerosol jet printer, but not an inkjet printer. The ink is shown to have a …

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