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Articles 1 - 30 of 31
Full-Text Articles in Engineering
An Analysis Of X-Band Radiation For Space Based Wireless Power Transmission, Noah W. Friz
An Analysis Of X-Band Radiation For Space Based Wireless Power Transmission, Noah W. Friz
Theses and Dissertations
The USAF is interested in developing a solar powered satellite power beaming system using X-Band radiation. To determine the expected level of transmission efficiency of the system, an atmospheric characterization and radiative transfer modeling system called LEEDR was employed. A study was conducted to validate LEEDRs performance while working with microwave frequencies by replicating brightness temperatures measured by a 10.7 GHz radiometer above the Pacific Ocean in 1999. The results were inconclusive. Brightness temperature vs. rain rate curves developed within other studies for X-Band radiation curves could be replicated within LEEDR, and therefore the associated path transmission and extinction values. …
Golng Off The Grid: Optimizing Solar Renewable Energy Systems At Remote Locations To Minimize Logistics Requirements, Increase Sustainability, And Strengthen Energy Assurance, Nathanael J. Thomsen
Golng Off The Grid: Optimizing Solar Renewable Energy Systems At Remote Locations To Minimize Logistics Requirements, Increase Sustainability, And Strengthen Energy Assurance, Nathanael J. Thomsen
Theses and Dissertations
Grid-based electrical infrastructure is unavailable at many remote locations including developing nation communities, isolated construction sites, and military contingency bases. Powering these locations with diesel generators requires regular fuel resupply, resulting in increased costs, environmental impacts, and burdensome logistics—making generators an obstacle for energy resiliency and sustainability. This research examines using solar renewable energy systems to replace generators at remote locations and presents a multi-objective optimization model that minimizes logistics variables. Replacing a single deployed generator would save over 500,000 gal of fuel annually, eliminating the need for 100 fuel tanker deliveries.
Analyzing Cost Effectiveness Of Photovoltaic Pavements, Ian N. Parks
Analyzing Cost Effectiveness Of Photovoltaic Pavements, Ian N. Parks
Theses and Dissertations
The United States Air Force (USAF) is the largest consumer of energy within the Department of Defense (DoD). As such, the USAF is continually looking for ways to reduce consumption, as well improving network resiliency and assuring supply. One potential method for addressing these items is focusing on applications of renewable energy. A specific application of renewable energy that could greatly benefit the USAF if viable would be photovoltaic (PV) pavements. PV pavements would be able to capitalize upon the large swathes of pavements on Air Force (AF) installations, while not being hampered by other concerns such as clear zones …
Optimized Off-Grid Energy Systems Using Climate-Based Energy Demand For Soft-Walled Facilities, Jay F. Pearson
Optimized Off-Grid Energy Systems Using Climate-Based Energy Demand For Soft-Walled Facilities, Jay F. Pearson
Theses and Dissertations
Remote contingency military operations often require the use of temporary facilities powered by inefficient diesel generators that are expensive to operate and maintain. Site planners can reduce operating costs by augmenting generators with hybrid energy systems, but they must select the optimal design configuration based on the region’s climate to meet the power demand at the lowest cost. To assist planners, this paper proposes two innovative, climate-optimized, hybrid energy system selection models. The first model is capable of selecting the facility insulation type, solar array size, and battery backup system to minimize the annual operating cost. The Hybrid Energy Renewable …
Plasma Treatment Method For Ohmic Contacts On Zinc Oxide Thin Film Transistors, Blaine Z. Underwood
Plasma Treatment Method For Ohmic Contacts On Zinc Oxide Thin Film Transistors, Blaine Z. Underwood
Theses and Dissertations
This research utilizes plasma treatments as a method to decrease the contact resistance on zinc oxide (ZnO) thin film transistors (TFT). In recent years, researchers have achieved gigahertz RF switch cutoff frequency with ZnO TFTs. To further increase the cutoff frequency, the total resistance of this device must be minimized. Modern ZnO TFTs are fabricated with submicron channel lengths, which contains minimal resistance due to the TFT channel, making contact resistance significant to the total resistance of the device. This research developed a method to integrate plasma treatments into the fabrication of ZnO TFT to decrease the contact resistance, thus …
Analysis Of Temperature And Humidity Effects On Horizontal Photovoltaic Panels, Corey J. Booker
Analysis Of Temperature And Humidity Effects On Horizontal Photovoltaic Panels, Corey J. Booker
Theses and Dissertations
The United States Air Force seeks to address power grid vulnerability and bolster energy resilience through the use of renewable energy sources. Air Force Institute of Technology engineers designed and manufactured control systems to monitor power production from the most widely-used silicon-based solar cells at 38 testing locations around the globe spanning the majority of climate types. Researchers conducted multivariate regression analysis to establish a statistical relationship between photovoltaic power output, ambient temperature, and humidity pertaining to monocrystalline and polycrystalline photovoltaic panels. Formulated models first characterized power output globally, then by specific climate type with general inaccuracy. Location-specific models are …
Special Perturbations On The Jetson Tx1 And Tx2 Computers, Tyler M. Moore
Special Perturbations On The Jetson Tx1 And Tx2 Computers, Tyler M. Moore
Theses and Dissertations
Simplified General Perturbations Number 4 (SGP4) has been the traditional algorithm for performing Orbit Determination (OD) onboard orbiting spacecraft. However, the recent rise of high-performance computers with low Size, Weight, and Power (SWAP) factors has provided the opportunity to use Special Perturbations (SP), a more accurate algorithm to perform onboard OD. This research evaluates the most efficient way to implement SP on NVIDIA’s Jetson TX series of integrated Graphical Processing Units (GPUs). An initial serial version was implemented on the Jetson TX1 and TX2's Central Processing Units (CPUs). The runtimes of the initial version are the benchmark that the runtimes …
Evaluation Of Resiliency In A Wide-Area Backup Protection System Via Model Checking, Kolby H. Elliot
Evaluation Of Resiliency In A Wide-Area Backup Protection System Via Model Checking, Kolby H. Elliot
Theses and Dissertations
Modern civilization relies heavily on having access to reliable power sources. Recent history has shown that present day protection systems are not adequate. Numerous backup protection (BP) systems have been proposed to mitigate the impact of primary protection system failures. Many of these novel BP systems rely on autonomous agents communicating via wide-area networks. These systems are highly complex and their control logic is based on distributed computing. Model checking has been shown to be a powerful tool in analyzing the behavior of distributed systems. In this research the model checker SPIN is used to evaluate the resiliency of an …
Bandwidth Analysis Of A Tightly-Packed Crossed-Dipole Array For Satellite Communications, Lawrence J. Lee
Bandwidth Analysis Of A Tightly-Packed Crossed-Dipole Array For Satellite Communications, Lawrence J. Lee
Theses and Dissertations
A bandwidth analysis of a tightly-packed crossed-dipole array antenna is presented in this thesis. A parametric study is described which varies the element spacing in the array and the resulting change in the terminal impedances is reported. The increased mutual coupling seen by the elements as a result of smaller element spacings is shown to minimize the variation in the value of the elements terminal currents across a 0.3 GHz to 3.0 GHz frequency range. This small variation in current translates into a minimal variation in the terminal impedances for a fixed excitation voltage. This is shown to be an …
Techniques For Low-Latency In Software-Defined Radio-Based Networks, Daniel D. Hart
Techniques For Low-Latency In Software-Defined Radio-Based Networks, Daniel D. Hart
Theses and Dissertations
Decreased budgets have pushed the United States Air Force towards using existing systems in new ways. The use of unmanned aerial vehicle swarms is one example of reuse of existing systems. One problem with the increased utilization of these swarms is the congestion of the electromagnetic spectrum. Software-defined or cognitive radios have been proposed as a basis for a potential robust communications solution. The present research aims to develop and test a genetic algorithm-based cognitive engine to begin looking at real-time engines that could be used in future swarms. Here, latency is the optimization objective of primary importance. In testing …
Influencing Effective Electrical Distribution Modernization Through Advanced Metering, Jared R. Erickson
Influencing Effective Electrical Distribution Modernization Through Advanced Metering, Jared R. Erickson
Theses and Dissertations
In 2013, the Department of Defense (DoD) required its services to implement advanced metering for the purpose of reducing energy usage (Department of Defense, 2013). Additionally, the DoD has aimed to improve its ability to assure a continuous energy supply to all of its installations. This study investigated processes for applying advanced meters on Air Force bases to increase energy assurance. This study also identified strategies for using advanced meters to influence infrastructure funding. This was accomplished through the use of extensive advanced meter data. The data was analyzed for outages and a procedure was created to locate outages in …
Predicting Solar Performance In A Contingency Environment To Meet Net-Zero Facility Power, Anthony D. Williams
Predicting Solar Performance In A Contingency Environment To Meet Net-Zero Facility Power, Anthony D. Williams
Theses and Dissertations
The U.S. government is involved in contingency operations all over the world and these operations require operational support and sustainment in these locations; this includes the reliable delivery of power to base infrastructure. The traditional means of delivering this support requirement in austere environments has been the use of diesel-power generation that has an extensive logistical and economic tail. The research sought out contingency solar applications that may be implemented and operated to offset the facility demand loads in the location to achieve net-zero power. This research explores the technical feasibility of a deployable photovoltaic microgrid to deliver power to …
An Application Of Con-Resistant Trust To Improve The Reliability Of Special Protection Systems Within The Smart Grid, Crystal M. Shipman
An Application Of Con-Resistant Trust To Improve The Reliability Of Special Protection Systems Within The Smart Grid, Crystal M. Shipman
Theses and Dissertations
This thesis explores an application of a con-resistant trust mechanism to improve the performance of communications-based special protection systems to further enhance their effectiveness and resiliency. New initiatives in the energy sector are paving the way for the emergent communications-based smart grid technology. Smart grids incorporate modern technologies in an effort to be more reliable and efficient. However, with the benefits of this new technology comes added risk. This research utilizes a con-resistant trust mechanism as a method to quickly identify malicious or malfunctioning protection system nodes in order to mitigate the resulting instabilities in the smart grid. The feasibility …
Application Of Game Theory To Improve The Defense Of The Smart Grid, Keith J. Ross
Application Of Game Theory To Improve The Defense Of The Smart Grid, Keith J. Ross
Theses and Dissertations
This thesis presents the development and evaluation of a distributed agent based system using reputation based trust and game theoretic techniques to improve the defense of the future smart grid from cyber-attack and equipment malfunctions. Future smart grid capabilities promise to leverage network technologies to revolutionize the production, transmission, distribution and consumption of electrical power. However, the internet like communication also increase the power grid's vulnerability to cyber-attack. This thesis uses simulation linking power systems with communication networks to demonstrate the benefits of a Distributed Decision Making Communication Enable Special Protection System (SPS) using reputation based trust and game theory …
Using Reputation Based Trust To Overcome Malfunctions And Malicious Failures In Electric Power Protection Systems, Jose E. Fadul
Using Reputation Based Trust To Overcome Malfunctions And Malicious Failures In Electric Power Protection Systems, Jose E. Fadul
Theses and Dissertations
This dissertation advocates the use of reputation-based trust in conjunction with a trust management framework based on network flow techniques to form a trust management toolkit (TMT) for the defense of future Smart Grid enabled electric power grid from both malicious and non-malicious malfunctions. Increases in energy demand have prompted the implementation of Smart Grid technologies within the power grid. Smart Grid technologies enable Internet based communication capabilities within the power grid, but also increase the grid's vulnerability to cyber attacks. The benefits of TMT augmented electric power protection systems include: improved response times, added resilience to malicious and non-malicious …
Characterizing Cyclostationary Features Of Digital Modulated Signals With Empirical Measurements Using Spectral Correlation Function, Mujun Song
Theses and Dissertations
Signal detection is widely used in many applications. Some examples include Cognitive Radio (CR) and military intelligence. CRs use signal detection to sense spectral occupancy. Without guaranteed signal detection, a CR cannot reliably perform its role. Similarly, signal detection is the first step for garnering an opponent's information. Wireless signal detection can be performed using many different techniques. Some of the most popular include matched filters, energy detectors (which use measurements such as the Power Spectral Density (PSD) of the signal), and Cyclostationary Feature Detectors (CFD). Among these techniques, CFD can be viewed as a compromise technique, in that it …
The Effect Of Synthetic Aperture Radar Image Resolution On Target Discrimination, John E. Mcgowan
The Effect Of Synthetic Aperture Radar Image Resolution On Target Discrimination, John E. Mcgowan
Theses and Dissertations
This research details the effect of spatial resolution on target discrimination in Synthetic Aperture Radar (SAR) images. Multiple SAR image chips containing targets and non-targets are used to test a baseline Automatic Target Recognition (ATR) system with reduced spatial resolution. Spatial resolution is reduced by lowering the pixel count or synthesizing a degraded image by filtering and reducing the pixel count. A two-parameter Constant False Alarm Rate (CFAR) detector is tested, and three feature sets, size, contrast, and texture, are used to train a linear classifier and to estimate probability density functions for the two classes. The results are scored …
Reputation-Based Trust For A Cooperative, Agent-Based Backup Protection Scheme For Power Networks, John F. Borowski
Reputation-Based Trust For A Cooperative, Agent-Based Backup Protection Scheme For Power Networks, John F. Borowski
Theses and Dissertations
This thesis research explores integrating a reputation-based trust mechanism with an agent-based backup protection system to improve the performance of traditional backup relay methods that are currently in use in power transmission systems. Integrating agent technology into relay protection schemes has been previously proposed to clear faults more rapidly and to add precision by enabling the use of adaptive protection methods. A distributed, cooperative trust system such as that used in peer-to-peer file sharing networks has the potential to add an additional layer of defense in a protection system designed to operate with greater autonomy. This trust component enables agents …
Investigating The Use Of Frequency Selective Surfaces In High Power Microwave Applications, Steven M. Pugh
Investigating The Use Of Frequency Selective Surfaces In High Power Microwave Applications, Steven M. Pugh
Theses and Dissertations
This thesis explores new territory with the theoretical investigation of the use of Frequency Selective Surfaces (FSS) in High Power Microwave (HPM) applications. Work was performed in a simulation environment where rectangular and ring-shaped FSS elements were evaluated. Incident electric field levels of 0.5MV/m were propagated toward the FSS in a plane wave that was perpendicular to the surface. Results show that the total electric field in the apertures of the FSS can reach more than 6MV/m. This necessitates the use of high strength dielectric materials surrounding the FSS to reduce the risk of electrical breakdown. It is shown that …
An Efficient And Effective Implementation Of The Trust System For Power Grid Compartmentalization, Juan M. Carlos Gonzalez
An Efficient And Effective Implementation Of The Trust System For Power Grid Compartmentalization, Juan M. Carlos Gonzalez
Theses and Dissertations
As utility companies develop and incorporate new technologies, such as moving to utility Internet technology based architecture and standard; it is crucial that we do so with history in mind. We know that traditional utility protection and control systems were not designed with security in their top priorities. This presents a danger in an environment where near real-time responses are required to ensure safe operations. As a consequence, system security becomes a burden to the system rather than necessary protection. Unfortunately, technology implementation is not the only concern. The number of utility privately-owned companies has multiplied as the market has …
Characterization Of Hardening By Design Techniques On Commercial, Small Feature Sized Field-Programmable Gate Arrays, Thomas E. Simmons
Characterization Of Hardening By Design Techniques On Commercial, Small Feature Sized Field-Programmable Gate Arrays, Thomas E. Simmons
Theses and Dissertations
In this thesis, a methodology is developed to experimentally test and evaluate a programmable logic device unde r gamma irradiation. The purpose of which is to determine the radiation effects and characterize the improvements of various hardening by design techniques. The techniques analyzed in this thesis include Error Correction Coding (ECC) and Triple Modular Redundancy (TMR). The TMR circuit includes three different functional implementations of adders compared to TMR voted circuits of those same adders. The TMR is implemented with the same functional adders and as a Functional TMR (FTMR) with three different function adders that are voted on. The …
Characterizing The Exhaust Plume Of The Three-Electrode Micro Pulsed Plasma Thrusters, Myeongkyo Seo
Characterizing The Exhaust Plume Of The Three-Electrode Micro Pulsed Plasma Thrusters, Myeongkyo Seo
Theses and Dissertations
Three-electrode micro-PPTs are a new version of two electrode micro-PPTs devices. Performance predictions and contamination expectations are essential characteristics needed by satellite designers. In order to focus on thruster specific impulse, thrust and efficiency, measuring the exhaust velocity or impulse bit and propellant consumption rate is essential. While this is not always possible to measure directly, focusing on the ejected mass from the PPT provides significant information allowing determination of these performance statistics. Specifically, focusing on exhaust angle distribution and velocity of the exhaust particles is the emphasis of this work. The results show that the three-electrode micro-PPT is more …
Optimized Robust Adaptive Networks In Supervisory Control And Data Acquisition Systems, Luis A. Oquendo Class
Optimized Robust Adaptive Networks In Supervisory Control And Data Acquisition Systems, Luis A. Oquendo Class
Theses and Dissertations
This thesis investigates the application of a Exponential Weighted Moving Average (EWMA) to be used as a memory buffer in conjunction with Special Protection Schemes (SPS) using the Electric Power and Communication Synchronizing Simulator (EPOCHS). It is proposed that using an SPS incorporating EWMA can compensate for the network layer lack of guarantee of packet delivery and provide for the stability and integrity of the power grid under a catastrophic event. The performance of the proposed SPS is evaluated using a discrete event computer simulation developed using the NS2 network simulator and the Power System Simulator for Engineering (PSS/E) power …
Power Generation By Harvesting Ambient Energy With A Micro-Electromagnetic Generator, James H. Shields
Power Generation By Harvesting Ambient Energy With A Micro-Electromagnetic Generator, James H. Shields
Theses and Dissertations
This thesis investigated the potential power output of a micro-electromagnetic generator fabricated using typical microfabrication materials and techniques. The design was based on a desire to free bio-implanted or remote electronic devices from batteries and their finite power supplies. A micro-electromagnetic generator could harvest energy from the ambient environment and power such devices indefinitely. Designs for the stator coil and rotor magnet components of the generator were optimized to produce maximum current density based upon electromagnetic theory. The relative orientation of the coil to the rotor and material selection for each component were considered. Coils were fabricated using low-resistance gold. …
Impacts Of Weather Variations On Energy Consumption Efforts At U.S. Air Force Installations, James S. Griffin
Impacts Of Weather Variations On Energy Consumption Efforts At U.S. Air Force Installations, James S. Griffin
Theses and Dissertations
Energy consumption is a national concern, as evidenced by federal laws aimed toward facility energy conservation measures for federal organizations. Factors, primarily weather variables, that significantly impact energy consumption must be addressed and understood to align resources and programs to meet federal energy reduction goals. An energy model was created and tested to produce an appropriate forecasting tool for energy consumption. Energy demand at Air Force installations primarily depends on climatic conditions, with a small portion attributed to a base level of non-climatic conditions, such as interior lighting and appliance loads. By gathering all energy consumption and meteorological data covering …
Selecting Electricity Generation Sources In Remote Locations, Kelly E. Kwan
Selecting Electricity Generation Sources In Remote Locations, Kelly E. Kwan
Theses and Dissertations
The purpose of this research was to investigate the impact of using a decision analysis technique for the selection of an electrical generation system for remote locations. Specifically, this thesis sought to answer five research questions addressing the types of energy sources used in remote locations, the decision-making processes used to identify these sources, the types of constraints incorporated in such a process, other valued factors, and their level of importance in relation to each other. The research questions were answered through a comprehensive literature review and the 10-Step Value-Focused Thinking Process on a specific case study in the National …
A Decision Model For Choosing Among Photovoltaic Technologies To Generate Electricity At Grid-Connected Air Force Facilities: A Value-Focused Approach, Mostyn O. Kellner
A Decision Model For Choosing Among Photovoltaic Technologies To Generate Electricity At Grid-Connected Air Force Facilities: A Value-Focused Approach, Mostyn O. Kellner
Theses and Dissertations
The United States is currently consuming fossil fuels faster than natural processes can replace them. Our nation's leaders recognize that a diverse energy portfolio including renewable energy is the key to maintaining our economy, security, and the environment. The federal government is by far the greatest energy consumer; thus, our nation's leaders have directed federal agencies to strive to increase the use of renewable energy at federal facilities. Solar electricity technologies, in the form of photovoltaics, have great potential in the renewable energy mix. Although a major strategy should be integrating photovoltaics into the design of new facilities, an important …
An Evaluation Of Wind Turbine Technology At Peterson Afb, Randy C. Combs
An Evaluation Of Wind Turbine Technology At Peterson Afb, Randy C. Combs
Theses and Dissertations
Wind energy technology is a viable source for attaining the emission reduction and renewable energy use goals set forth by the executive office. In accordance with Executive Orders, the Air Force must reduce greenhouse emissions and energy consumption, and expand the use of renewable energy sources within its facilities nation-wide by year 2010. This mandate requires that the Air Force look at alternative electrical production and rely more on such renewable energy resources as wind power. The specific problem addressed by this research is whether on-site wind energy generation can be more economically feasible than the conventional energy consumption at …
A Value Focused Thinking Model For The Development And Selection Of Electrical Energy Source Alternatives At Military Installations, Gregory T. Schanding
A Value Focused Thinking Model For The Development And Selection Of Electrical Energy Source Alternatives At Military Installations, Gregory T. Schanding
Theses and Dissertations
Electrical power on military installations is vital for mission accomplishment. Most installations obtain electrical power from a local commercial utility. Although commercial power service has a very low interruption rate, the threat of a sustained power outage resulting from a terrorist act or a natural disaster is of concern. The military should posture itself to prevent such power outages and prepare to mitigate the adverse effects associated with the loss of power. This thesis presents a Value Focused Thinking approach to the development of a decision analysis model to assist a decision maker at a military installation in the generation …
A Life Cycle Assessment And Economic Analysis Of Wind Turbines Using Monte Carlo Simulation, Edward J. Liberman
A Life Cycle Assessment And Economic Analysis Of Wind Turbines Using Monte Carlo Simulation, Edward J. Liberman
Theses and Dissertations
The United States depends heavily on nonrenewable fossil fuels to generate electricity. Using renewable energy sources, such as wind, could reduce air emissions and fossil fuel dependency. Previous studies have examined the life cycle costs and environmental impacts of using wind to generate electricity, but results have varied due to inconsistent modeling assumptions. This research uses Monte Carlo simulation to conduct an economic payback analysis and life cycle assessment of 11 modern, utility-scale wind turbines. Hourly meteorological data was used to evaluate 239 U.S. locations. For each location, the wind turbine with the shortest median payback period was assumed to …