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2012

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Articles 3211 - 3240 of 6306

Full-Text Articles in Engineering

Streamlining The Change-Over Protocol For The Rpa Mission Intelligence Coordinator By Way Of Situation Awareness Oriented Design And Discrete Event Simulation, John P. Machuca Mar 2012

Streamlining The Change-Over Protocol For The Rpa Mission Intelligence Coordinator By Way Of Situation Awareness Oriented Design And Discrete Event Simulation, John P. Machuca

Theses and Dissertations

Incredible loiter times coupled with the ability to make extremely detailed collections at significant stand-off distances with a relatively expendable platform has made demand for, and diversity of, Remotely Piloted Aircraft (RPA) operations grow at voracious rates. Conversely, financial resources are becoming increasingly constrained. As such, innovators are looking to maximize the effectiveness of existing personnel and assets by considering concepts such as simultaneous Multiple Aircraft Control (MAC) by a single aircrew. Research has identified procedural inefficiencies in current operations as well as substantial impediments to MAC implementation, including dynamic task saturation and communication challenges. An identified inefficiency afflicting both …

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Using Hybrid Simulation/Analytical Queueing Networks To Capacitate Usaf Air Mobility Command Passenger Terminals, Meredithe A. Jessup Ii Mar 2012

Using Hybrid Simulation/Analytical Queueing Networks To Capacitate Usaf Air Mobility Command Passenger Terminals, Meredithe A. Jessup Ii

Theses and Dissertations

The objective of this study is to model operations at an airport passenger terminal to determine the optimal service capacities at each station given estimated passenger flow patterns and service rates. The central formulation is an open Jackson queueing network that can be applied to any USAF Air Mobility Command (AMC) terminal regardless of passenger type mix and flow data. A complete methodology for analyzing passenger flows and queue performance of a single flight is produced and then embedded in a framework to analyze the same for multiple departing flights. Queueing network analysis (QNA) is used because no special software …

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Analysis Of Kc-46 Live-Fire Risk Mitigation Program Testing, Chad N. Chamberlain Mar 2012

Analysis Of Kc-46 Live-Fire Risk Mitigation Program Testing, Chad N. Chamberlain

Theses and Dissertations

Increased emphasis from the Director of Operational Test and Evaluation (DOT&E) over the past few years to include statistical rigor in all testing has brought an augmented look at testing across the Department of Defense. This thesis examines the methodology currently used in live fire testing, particularly in the case of risk mitigation of the KC-46 dry-bay fire test program. The thesis addresses gaps within the methodology and analyzes the results of a statistically rigorous test. The research furthers work on modeling the characterization of ballistic impact flash by validating concurrent models and characterizing the errors prone to these models …

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Combat Identification Of Synthetic Aperture Radar Images Using Contextual Features And Bayesian Belief Networks, John X. Situ Mar 2012

Combat Identification Of Synthetic Aperture Radar Images Using Contextual Features And Bayesian Belief Networks, John X. Situ

Theses and Dissertations

Given the nearly infinite combination of modifications and configurations for weapon systems, no two targets are ever exactly the same. Synthetic Aperture Radar (SAR) imagery and associated High Range Resolution (HRR) profiles of the same target will have different signatures when viewed from different angles. To overcome this challenge, data from a wide range of aspect and depression angles must be used to train pattern recognition algorithms. Alternatively, features invariant to aspect and depression angle must be found. This research uses simple segmentation algorithms and multivariate analysis methods to extract contextual features from SAR imagery. These features used in conjunction …

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Mitigating Diminishing Manufacturing Sources/Material Shortages (Dms/Ms) And Obsolescence For The T-6 Canopy Fracturing Initiation System (Cfis), Richard P. Carrano Mar 2012

Mitigating Diminishing Manufacturing Sources/Material Shortages (Dms/Ms) And Obsolescence For The T-6 Canopy Fracturing Initiation System (Cfis), Richard P. Carrano

Theses and Dissertations

The Joint Primary Aircraft Training System (JPATS) lost the supplier for its canopy fracturing initiation system (CFIS) with no prospect for a replacement. This forced a complete CFIS redesign to supply both an active production line and sustain fielded aircraft. Compounding the problem, the existing CFIS became obsolete, which forced an interim design to be produced until a final long term solution was fielded. This thesis developed a method to optimize the redesign by determining the lowest cost path for both fielding the interim design and phasing in the final retrofit. Using the Excel Solver® modeling program, an optimal rate …

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An Analysis Of Turnover Intentions: A Reexamination Of Air Force Civil Engineering Company Grade Officers, Joshua D. Connell Mar 2012

An Analysis Of Turnover Intentions: A Reexamination Of Air Force Civil Engineering Company Grade Officers, Joshua D. Connell

Theses and Dissertations

A potential retention problem is facing company grade officers (CGOs) in the Air Force Civil Engineer (CE) career field. This is due to the stress caused by a demanding workload experienced during a prolonged period of conflict (Iraq and Afghanistan), which is compounded by a reduction in force. The possibility of reduced retention is thus a concern for CE leadership. Based on past research, and the prior study conducted by Riddel (2010), a new model of turnover intentions was developed. The new model expands on Riddel's simplified model of turnover and attempts to focus on key factors that may help …

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Evaluation Of Municipal Wastewater Treatment Plant Activated Sludge For Biodegradation Of Propylene Glycol As An Aircraft Deicer, Justin D. Delorit Mar 2012

Evaluation Of Municipal Wastewater Treatment Plant Activated Sludge For Biodegradation Of Propylene Glycol As An Aircraft Deicer, Justin D. Delorit

Theses and Dissertations

Aircraft deicing fluid used at airport facilities is often collected for treatment or disposal in order to prevent serious ecological threats to nearby surface waters. This study investigated lab scale degradation of propylene glycol (PG), the active ingredient in a common aircraft deicing fluid, by way of a laboratory-scale sequencing batch reactor containing municipal waste water treatment facility activated sludge (AS) performing simultaneous organic carbon oxidation and nitrification. The ability of AS to remove PG was evaluated by studying the biodegradation and sorption characteristics of PG in an AS medium. The results indicate sorption may play a role in the …

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Asset Management: Roof Maintenance And Facility Energy Retrofits, Joseph P. Dirosario Mar 2012

Asset Management: Roof Maintenance And Facility Energy Retrofits, Joseph P. Dirosario

Theses and Dissertations

The United States Air Force (USAF) needs aggressive new techniques to compliment its asset management of its real estate portfolio. Air Force officials are experiencing budget cuts that have led to degraded facility infrastructure. Two areas of operations in which there are opportunities to improve the asset management of Air Force facilities are roof maintenance and energy retrofits. Information obtained via a geospatial information systems analysis revealed that the current state of the rooftop maintenance program was deficient and supported strategic sourcing as a potential solution to the program's deficiencies. In addition, two methodologies were created to gauge the effectiveness …

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Turnover Intentions: A Quantitative Analysis Of Comments From Air Force Civil Engineering Company Grade Officers, Tj E. Gabrielson Mar 2012

Turnover Intentions: A Quantitative Analysis Of Comments From Air Force Civil Engineering Company Grade Officers, Tj E. Gabrielson

Theses and Dissertations

Voluntary turnover is a concern for the military and many other organizations from a financial and performance standpoint. This study applied grounded theory to code and network comments provided by CE officers in 2010. The results of this study found the most influential construct that predicts turnover intentions to be the relationship of OPSTEMPO influencing interrole conflict. This conflict is increased by the workload at home station due to under manning within CE. OPSTEMPO is an important aspect of a military member's decision to stay or leave the service because it was found to interact with a multitude of other …

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Modeling, Simulation, And Flight Test For Automatic Flight Control Of The Condor Hybrid-Electric Remote Piloted Aircraft, Christopher Giacomo Mar 2012

Modeling, Simulation, And Flight Test For Automatic Flight Control Of The Condor Hybrid-Electric Remote Piloted Aircraft, Christopher Giacomo

Theses and Dissertations

This thesis describes the modeling and verification process for the stability and control analysis of the Condor hybrid-electric Remote-Piloted Aircraft (HE-RPA). Due to the high-aspect ratio, sailplane-like geometry of the aircraft, both longitudinal and lateral/directional aerodynamic moments and effects are investigated. The aircraft is modeled using both digital DATCOM as well as the JET5 Excel-based design tool. Static model data is used to create a detailed assessment of predictive flight characteristics and PID autopilot gains that are verified with autonomous flight test. PID gain values were determined using a six degree of freedom linear simulation with the Matlab/SIMULINK software. Flight …

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Infrastructure Asset Management Modeling Through An Analysis Of The Air Force Strategic Vision And Goals, Marie T. Harnly Mar 2012

Infrastructure Asset Management Modeling Through An Analysis Of The Air Force Strategic Vision And Goals, Marie T. Harnly

Theses and Dissertations

Effective asset management requires an overarching model that establishes a framework for decision-makers. This research project develops a strategic level asset management model for varying types of infrastructure that provides guidance for effective asset management. The strategic model also incorporates Next Generation Information Technology initiatives into a single coherent system to streamline the top-down, bottom-up flow of information. The strategic model is applicable to agencies with a large, varying infrastructure inventory and limited resources. This research also develops an improved performance modeling tool, a critical component of the strategic model. This tool objectively prioritizes maintenance and repair projects according to …

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Understanding The Impact Of Bead Type On Paint And Thermoplastic Pavement Markings, Joshua D. Hollingsworth Mar 2012

Understanding The Impact Of Bead Type On Paint And Thermoplastic Pavement Markings, Joshua D. Hollingsworth

Theses and Dissertations

Each year the United States spends approximately two billion dollars maintaining pavement markings. In addition, an impending Federal policy establishing a minimum retro-reflectivity value for pavement markings has driven asset managers to develop performance models to effectively and efficiently manage these high quantity, low cost assets. Research over the past decade has sought to identify and understand the many factors influencing pavement marking degradation. Despite the fact that reflective glass beads are foundational to pavement marking retro-reflectivity, little research has specifically considered the impacts of bead type. The purpose of this study is to quantify the impact that bead type …

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Firm Fixed Price And Cost Plus Fixed Fee Construction Contracts In Iraq And Afghanistan, Lindsay M. Jaszkowiak Mar 2012

Firm Fixed Price And Cost Plus Fixed Fee Construction Contracts In Iraq And Afghanistan, Lindsay M. Jaszkowiak

Theses and Dissertations

Firm Fixed Price (FFP) and Cost Plus Fixed Fee (CPFF) contract types have been utilized the most for construction in the Iraq and Afghanistan theaters. Often construction occurs in contested regions that are known to be particularly challenging, unpredictable, and unstable. The objective of this study was to analyze the performance of these two contract types in the contingency environment, and to determine what internal and external factors influence contact success the most. First, the author evaluated existing construction performance data using bivariate analysis and analysis of variance to identify differences in contract type. Next, a quantitative/qualitative questionnaire was administered …

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Leading Indicator Analysis For High Speed Sled Test Programs, Laurie C. Knorr Mar 2012

Leading Indicator Analysis For High Speed Sled Test Programs, Laurie C. Knorr

Theses and Dissertations

Leading Indicators (LI) were introduced to the Systems Engineering (SE) community in 2005. These measures are used to evaluate the effectiveness of how a specific work activity is applied on a project in a manner that provides information about impacts that are likely to affect the system performance. The LIs are designed to give a project manager/systems engineer insight into where their development project is heading and a chance to implement corrective actions early. This research strives to apply LIs to the testing community, specifically high speed sled testing, to improve the testing process and, in turn, improve the quality …

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Analysis Of The Impact Of Data Normalization On Cyber Event Correlation Query Performance, Smile T. Ludovice Mar 2012

Analysis Of The Impact Of Data Normalization On Cyber Event Correlation Query Performance, Smile T. Ludovice

Theses and Dissertations

A critical capability required in the operation of cyberspace is the ability to maintain situational awareness of the status of the infrastructure elements that constitute cyberspace. Event logs from cyber devices can yield significant information, and when properly utilized they can provide timely situational awareness about the state of the cyber infrastructure. In addition, proper Information Assurance requires the validation and verification of the integrity of results generated by a commercial log analysis tool. Event log analysis can be performed using relational databases. To enhance database query performance, previous literatures affirm denormalization of databases. Yet database normalization can also increase …

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Optimization Of Nanoscale Zero-Valent Iron For The Remediation Of Groundwater Contaminants, Andrew W. E. Mcpherson Mar 2012

Optimization Of Nanoscale Zero-Valent Iron For The Remediation Of Groundwater Contaminants, Andrew W. E. Mcpherson

Theses and Dissertations

Nanoscale zero-valent iron (nZVI) is an emerging tool for the remediation of groundwater contaminants. The nanoparticles are capable of reductively destroying or immobilizing a wide range of contaminants. Their small size results in a high surface area to mass ratio, making them much more reactive compared to their more-coarse predecessors. Small particle size also allows nZVI particles to be injected directly into contaminated areas via a well, limiting the above-ground footprint and allowing access to contaminated areas that are beyond the reach of some conventional methods. nZVI technology has the potential to facilitate remediation in difficult situations, improve remediation outcomes, …

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An Enhanced Fuselage Ultrasound Inspection Approach For Ishm Purposes, Francisco Ospina Mar 2012

An Enhanced Fuselage Ultrasound Inspection Approach For Ishm Purposes, Francisco Ospina

Theses and Dissertations

This effort constitutes a systems engineering approach in which the materials science, ultrasound structural health monitoring, flight and maintenance operations, and relevant aeronautical policies and programs are involved to explore the evolution and characterization of structural cracks in aircraft fuselage structures in which the loads are varying. During flight, an aircraft fuselage skin and structure are subjected to varied cyclic loads, which can cause embedded cracks and other damage features to change their characteristics due to loading effects. The current research is based in the application of finite element modeling techniques using COMSOL and PZFLEX software to characterize the behavior …

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Discrete Event Simulation Of Distributed Team Communication Architecture, Travis J. Pond Mar 2012

Discrete Event Simulation Of Distributed Team Communication Architecture, Travis J. Pond

Theses and Dissertations

As the United States Department of Defense continues to increase the number of Remotely Piloted Aircraft (RPA) operations overseas, improved Human Systems Integration becomes increasingly important. RPA systems rely heavily on distributed team communications determined by systems architecture. Two studies examine the effects of systems architecture on operator workload of US Air Force MQ-1/9 operators. The first study ascertains the effects of communication modality changes on mental workload using the Improved Research Integration Pro (IMPRINT) software tool to estimate pilot workload. Allocation of communication between modalities minimizes workload. The second study uses IMPRINT to model Mission Intelligence Controllers (MICs) and …

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Analysis Of Leadership In Energy And Environmental Design® Construction In The Air Force, James M. Rozzoni Mar 2012

Analysis Of Leadership In Energy And Environmental Design® Construction In The Air Force, James M. Rozzoni

Theses and Dissertations

The Air Force uses the Leadership in Energy and Environmental Design (LEED) rating system as a third party verification system to ensure sustainable and resource-conscious facilities. The Federal Government has implemented several mandates in recent years that require certain milestones be met for energy reduction, water conservation, renewable energy use, and so forth. This research aims to determine how the Air Force has implemented LEED through credit analysis, and to better understand why LEED is being used in this way. Using a database of 172 military construction projects, the research evaluates the frequency of credit usage individually and by category. …

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A Spatial Risk Analysis Of Oil Refineries Within The United States, Zachary L. Schiff Mar 2012

A Spatial Risk Analysis Of Oil Refineries Within The United States, Zachary L. Schiff

Theses and Dissertations

A risk analysis methodology is necessary to manage the potential effects of oil refinery outages to the increasingly connected, interdependent critical infrastructure of the United States. Following the terrorist attacks of 9/11, the lack of a critical infrastructure risk mitigation strategy was identified as an area for improvement. In both the 9/11 attacks and Hurricane Katrina, cascading failures occurred due to the interdependencies among infrastructures and their spatial relationships. Furthermore, the U.S. military is dependent on oil refining capability and a major shortage could potentially have devastating effects on mission accomplishment. As a result, a need has emerged to better …

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Biodegradation Of Organophosphate Chemical Warfare Agents By Activated Sludge, Steven J. Schuldt Mar 2012

Biodegradation Of Organophosphate Chemical Warfare Agents By Activated Sludge, Steven J. Schuldt

Theses and Dissertations

Organophosphates (OPs) have been widely used as Chemical Warfare Agents (CWAs) as well as pesticides since World War II and still remain a threat to national security. While efforts have been taken at military installations and civilian communities to secure these chemicals and prevent their misuse, a determined adversary could still obtain and deploy them to injure, kill, or instill terror. The lethal properties of this group of compounds are primarily owed to their irreversible inhibition of the enzyme acetyl cholinesterase (AChE) and thus may alter the human nervous system or affect the hormonal balance of children in particular. In …

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Structural Health Monitoring Of M1114 High Mobility Multipurpose Wheeled Vehicle Armor System, Frank T. Sha Mar 2012

Structural Health Monitoring Of M1114 High Mobility Multipurpose Wheeled Vehicle Armor System, Frank T. Sha

Theses and Dissertations

The M1114 High Mobility Multipurpose Wheeled Vehicle (HMMWV) has been the workhorse vehicle of the U.S. Armed Forces in Afghanistan and Iraq. Donald Rumsfeld, Secretary of Defense, was faced with massive public criticism in 2004 for not equipping our military personnel in Afghanistan and Iraq with M1114s that had the proper ballistic armor. In May 2004, a $618M Senate Bill was passed to increase the production level of HMMWVs and improve their ballistic protection capabilities while minimizing additional weight. While the military is taking advantage of using composite armor on the HMMWV, it does not have a rigorous method to …

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The Application Of Sensors On Guardrails For The Purpose Of Real Time Impact Detection, Matthew D. Sturtevant Mar 2012

The Application Of Sensors On Guardrails For The Purpose Of Real Time Impact Detection, Matthew D. Sturtevant

Theses and Dissertations

The United States roadway system has deteriorated over time due to its age, increasing delays in completing preventative maintenance, and the lack of timely repairs following damage to the infrastructure. Proper asset management drives the need for generalized methods to integrate new sensing capabilities into existing Intelligent Transportation Systems in a time efficient and cost effective manner. In this thesis, we present a methodology for the deployment of new sensors into an existing ITS system. The proposed methodology employs a three phase approach that incorporates data modeling, spatial analysis in Geographic Information Systems, and cost optimization to provide enhanced decision …

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Implementing A Quantitative Analysis Design Tool For Future Generation Interfaces, Brandon M. Webster Mar 2012

Implementing A Quantitative Analysis Design Tool For Future Generation Interfaces, Brandon M. Webster

Theses and Dissertations

The implementation of Multi-Aircraft Control (MAC) for use with Remotely Piloted Aircraft (RPA) has resulted in the need of a platform to evaluate interface design. The Vigilant Spirit Control Station (VSCS), developed by the Air Force Research Laboratory, addresses this need by permitting the rapid prototyping of different interface concepts for future MAC-enabled systems. A human-computer interaction (HCI) Index, originally applied to multi-function displays was applied to the prototype Vigilant Spirit interface. A modified version of the HCI Index was successfully applied to perform a quantitative analysis of the baseline VSCS interface and two modified interface designs. The modified HCI …

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Rapid Prototype Development Of A Remotely-Piloted Aircraft Powered By A Hybrid-Electric Propulsion System, Michael P. Molesworth, Jacob K. English Mar 2012

Rapid Prototype Development Of A Remotely-Piloted Aircraft Powered By A Hybrid-Electric Propulsion System, Michael P. Molesworth, Jacob K. English

Theses and Dissertations

Remotely-Piloted Aircraft (RPA) provide users with unique mission capabilities, particularly on-demand overhead surveillance. However, a capability gap has been identified between the range and endurance of RPAs powered by internal combustion engines (ICE) and the reduced acoustic signature and smaller logistical footprint associated with electric-powered RPAs. This research, sponsored by the Office of the Secretary of Defense, aims at advancing systems engineering education by evaluating the utility of a tailored systems engineering approach. The tailored systems engineering approach used herein focuses on conducting a concept evaluation study on the rapid prototype development of a parallel hybrid-electric RPA (HE-RPA) and its …

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Material Characterization For Composite Materials In Load Bearing Wave Guides, Gabriel Almodovar Mar 2012

Material Characterization For Composite Materials In Load Bearing Wave Guides, Gabriel Almodovar

Theses and Dissertations

This study will establish a methodology to examine samples of composite material for application in a load bearing waveguide. The composite material will operate in a specific frequency range for applications in small RPAs. A graphite epoxy stiffening component will be primarily considered. Different nickel, graphene, and carbon nanotube (CNT) coatings and films will be applied to the graphite epoxy. Tests will determine the material's radio frequency (RF) performance for application as an antenna/waveguide component. The study will use scattering (S) parameters determined from a network analyzer to collect these data. The S parameters will then be used to resolve …

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Satellite Relative Motion Control For Mit's Spheres Program, Samuel P. Barbaro Mar 2012

Satellite Relative Motion Control For Mit's Spheres Program, Samuel P. Barbaro

Theses and Dissertations

Autonomous formation flight concepts and algorithms have great potential to revolutionize spacecraft operations enabling missions to perform autonomous docking, in-space refueling, in-space robotic assembly, and space debris removal. Such tasks require the implementation of speed and path control algorithms to maneuver satellites along relative paths with specified rates along those paths. This thesis uses MATLAB® and SIMULINK® to design and simulate a control algorithm capable of providing relative speed and path control between satellites with a pointing error of less than two degrees, a position error of less than two millimeters, and a millimeter per second of velocity error. The …

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Integration, Testing And Validation, Of A Small Hybrid-Electric Remotely-Piloted Aircraft, Joseph K. Ausserer Mar 2012

Integration, Testing And Validation, Of A Small Hybrid-Electric Remotely-Piloted Aircraft, Joseph K. Ausserer

Theses and Dissertations

Parallel hybrid-electric technology offers a wide variety of new mission capabilities including low-observable loiter operations and increased fuel efficiency for small remotely-piloted aircraft. This research focused on the integration, validation, and testing of a hybrid-electric propulsion system consisting of commercially available components to fabricate a small remotely-piloted aircraft capable of extended low-observable operation. Three novel aspects contributed to the success of the design: optimization of the propulsive components to the integrated system, torque control of the components for additive power, and a one-way bearing/ pulley mechanism (patent pending) mechanically linking the hybrid system components. To the knowledge of the author …

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Cubesat Attitude Determination And Helmholtz Cage Design, Megan R. Brewer Mar 2012

Cubesat Attitude Determination And Helmholtz Cage Design, Megan R. Brewer

Theses and Dissertations

A method of 3-axis satellite attitude determination utilizing six body-fixed light sensors and a 3-axis magnetometer is analyzed. A Helmholtz cage is designed, built, and tested to provide a dynamic, 3-axis, uniform magnetic field to cancel the Earth's magnetic field and create an environment similar to the geomagnetic field a satellite would experience on-orbit. A CubeSat is provided the inertial magnetic vector and Sun vector, which are combined with data from the light sensors and magnetometer in a CubeSat. Attitude is estimated on-board the CubeSat via the optimal fast quaternion estimation algorithm. The capabilities of the Helmholtz cage, including the …

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Computational Analysis And Characterization Of Rc-135 External Aerodynamics, Michael G. Chenery Mar 2012

Computational Analysis And Characterization Of Rc-135 External Aerodynamics, Michael G. Chenery

Theses and Dissertations

Both the RC-135V/W Rivet Joint (RJ) and the RC-135U Combat Sent (CS) aircraft are United States Air Force (USAF) electronics reconnaissance platforms. The RJ is the USAF's standard airborne signals intelligence (SIGINT) gathering platform, while the CS is designed to collect technical intelligence on adversary radar emitter systems. Both aircraft are extensively modified C-135's characterized by protruding cheek fairings along the sides of the fuselage forward of the wings as well as the addition of numerous antennas along the top and bottom of the fuselage. The major distinguishing feature between the two variants is the nose radome, wherein the RJ …

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