Characteristics Of A High Intensity, Pulsed, Potassium Vapor Laser In A Heat Pipe,
2011
Air Force Institute of Technology
Characteristics Of A High Intensity, Pulsed, Potassium Vapor Laser In A Heat Pipe, Edward J. Hurd
Theses and Dissertations
This thesis research paper presents the results of experiments using an optically pumped, pulsed potassium vapor laser in a heat pipe. The absorption on the potassium D2 line, output laser characteristics, and Raman scattering in potassium vapor are discussed. The spectral full width at half maximum (FWHM) of the D2 absorption line was much greater than predicted values for pressure broadening due to the high number density of potassium atoms and the long path length. At 320°C and 0 torr of helium, the FWHM was 765 GHz. At 100 torr it was 968 GHz. At 200 torr it …
A Simple Non-Destructive Method For Characterizing Non-Dispersive, Low-Loss Dielectrics,
2011
Air Force Institute of Technology
A Simple Non-Destructive Method For Characterizing Non-Dispersive, Low-Loss Dielectrics, Thomas S. Olney
Theses and Dissertations
It is shown how permittivity can be extracted via time domain reflection data from a perfect electric conductor (PEC) backed planar sample of a low-loss, non-dispersive dielectric using two rectangular Ku-band waveguide aperture probes with attached PEC flange plates of the same geometry but different dimensions. Of critical importance is being able to identify the reflection from the edge of the flange plate in the parallel plate region created by the plate and the PEC backing of the sample. A signal processing method that takes advantage of physical insight into the geometry and superposition is developed for identifying this edge …
Effects Of Cyclic Prefix Jamming Versus Noise Jamming In Ofdm Signals,
2011
Air Force Institute of Technology
Effects Of Cyclic Prefix Jamming Versus Noise Jamming In Ofdm Signals, Amber L. Scott
Theses and Dissertations
Signal jamming of an orthogonal frequency-division multiplexing (OFDM) signal is simulated in MATLAB. Two different means of jamming are used to see, which is a more efficient way to disrupt a signal using the same signal power. The first way is a basic additive white Gaussian noise (AWGN) jammer that equally jams the entire signal. The second way is an AWGN jammer that targets only the cyclic prefix (CP) of the signal. These two methods of jamming are simulated using different channel models and unknowns to get varying results. The three channel models used in the simulations are the no …
Radiation Induced Fault Detection, Diagnosis, And Characterization Of Field Programmable Gate Arrays,
2011
Air Force Institute of Technology
Radiation Induced Fault Detection, Diagnosis, And Characterization Of Field Programmable Gate Arrays, Thomas B. Getz
Theses and Dissertations
The development of Field Programmable Gate Arrays (FPGAs) has been a great achievement in the world of micro-electronics. One of these devices can be programmed to do just about anything, and replace the need for thousands of individual specialized devices. Despite their great versatility, FPGAs are still extremely vulnerable to radiation from cosmic waves in space and from adversaries on the ground. Extensive research has been conducted to examine how radiation disrupts different types of FPGAs. The results show, unfortunately, that the newer FPGAs with smaller technology are even more susceptible to radiation damage than the older ones. This research …
High Frequency Direction Finding Using Structurally Integrated Antennas On A Large Airborne Platform,
2011
Air Force Institute of Technology
High Frequency Direction Finding Using Structurally Integrated Antennas On A Large Airborne Platform, Clair F. Corbin
Theses and Dissertations
Estimating the angle of arrival (AOA) of a high frequency (HF) signal, 2-32 MHz, is challenging, especially if the antenna array is installed on a platform with dimensions on the order of one wavelength. Accurate AOA estimates are necessary for search and rescue operations and geolocating RF emitters of interest. This research examines the performance of a direction finding (DF) system using structurally integrated (SI) antennas installed on an airborne platform which allows the aircraft structure to become the receiving element. Two simulated DF systems are analyzed at 4 and 11 MHz. The relationship between the number of SI antennas …
Malicious And Malfunctioning Node Detection Via Observed Physical Layer Data,
2011
Air Force Institute of Technology
Malicious And Malfunctioning Node Detection Via Observed Physical Layer Data, Tyler J. Hardy
Theses and Dissertations
There are many mechanisms that can cause inadequate or unreliable information in sensor networks. A user of the network might be interested in detecting and classifying specific sensors nodes causing these problems. Several network layer based trust methods have been developed in previous research to assess these issues; in contrast this work develops a trust protocol based on observations of physical layer data collected by the sensors. Observations of physical layer data are used for decisions and calculations, and are based on just the measurements collected by the sensors. Although this information is packaged and distributed on the network layer, …
Characterization Of Noise Technology Radar Signal Detectability Using A Non-Cooperative Receiver,
2011
Air Force Institute of Technology
Characterization Of Noise Technology Radar Signal Detectability Using A Non-Cooperative Receiver, Daniel V. Atienza
Theses and Dissertations
As Noise Technology Radar (NTR) systems emerge, there is a need for non-cooperative, non-matched filter detection and exploitation. This work is based on that need and AFIT's Noise Network (NoNET) radar system. These signals are associated with Low Probability of Detection/ Intercept (LPD/LPI) signals. Quadrature Mirror Filter Banks (QMFB) has been effectively used for non-cooperatively detecting structured LPD/LPI signals and extracting various waveform characteristics. However, the QMFB process performance with unstructured NTR signals was challenging and motivated a need for a transformed QMFB. This transform was based on AFIT research by Gronholz and Mims (G-M), who used a multi-channel receiver …
Routing Uavs To Co-Optimize Mission Effectiveness And Network Performance With Dynamic Programming,
2011
Air Force Institute of Technology
Routing Uavs To Co-Optimize Mission Effectiveness And Network Performance With Dynamic Programming, Spenser D. Lee
Theses and Dissertations
In support of the Air Force Research Laboratory's (AFRL) vision of the layered sensing operations center, command and control intelligence surveillance and reconnaissance (C2ISR) more focus must be placed on architectures that support information systems, rather than just the information systems themselves. By extending the role of UAVs beyond simply intelligence, surveillance, and reconnaissance (ISR) operations and into a dual-role with networking operations we can better utilize our information assets. To achieve the goal of dual-role UAVs, a concrete approach to planning must be taken. This research defines a mathematical model and a non-trivial deterministic algorithmic approach to determining UAV …
Optical Metamaterial Design, Fabrication And Test,
2011
Air Force Institute of Technology
Optical Metamaterial Design, Fabrication And Test, Jack P. Lombardi
Theses and Dissertations
Metamaterials, materials that make use of naturally occurring materials and designed structures to create materials with special properties not found in nature, are a fascinating new area of research, combining the fields of physics, microfabrication, and material science. This work will focus on the development of metamaterials operating in the visible and infrared which will be constructed and tested for basic optical properties. Possible applications for these materials will not be investigated. The this work will go into the fabrication and test of layered metal-dielectric structures, called layered metamaterials, as these structures hold potential for applications in advanced optical systems. …
Xdl-Based Hard Macro Generator,
2011
Brigham Young University - Provo
Xdl-Based Hard Macro Generator, Subhrashankha Ghosh
Theses and Dissertations
In a conventional hardware design flow, the compilation process to create the physical circuit on the FPGA takes a long time. HMFlow is a design flow that reduces the compilation time by using pre-compiled modules called hard macros. HMFlow uses System Generator to create the designs, which are then converted to hard macros. The hard macro creation process takes a long time and a possible solution is a hard macro generator called XdlCoreGen, which is described in this thesis. XdlCoreGen can quickly create fully mapped and placed hard macros using XDL. XDL is a human readable design format that describes …
Modal Logic And Its Applications, Explained Using Puzzles And Examples,
2011
Portland State University
Modal Logic And Its Applications, Explained Using Puzzles And Examples, Marek Perkowski
Electrical and Computer Engineering Faculty Publications and Presentations
1.We shall be concerned, at first, with alethicmodal logic, or modal logic tout court. 2.The starting point, once again, is Aristotle, who was the first to study the relationship between modal statements and their validity. 3.However, the great discussion it enjoyed in the Middle Ages. 4.The official birth date of modal logic is 1921, when Clarence Irving Lewis wrote a famous essay on implication.
Single-Beam Holographic Tomography Creates Images In Three Dimensions,
2011
The Catholic University of America
Single-Beam Holographic Tomography Creates Images In Three Dimensions, George Nehmetallah, Partha P. Banerjee, Nickolai Kukhtarev
Electrical and Computer Engineering Faculty Publications
In digital holography (DH), the interference between light scattered from an object and a reference wave is recorded using a CCD camera. DH has various advantages over analog holography: no film processing is needed, reconstruction is performed using numerical methods, and no further experimental setup is necessary. However, one of the disadvantages of DH is that current CCDs have a resolution of approximately 1,000 lines/mm, which is less than that of photographic film.
Anisotropic Electrical Properties Of Nanostructured Metallic Thin Films,
2011
University of Dayton
Anisotropic Electrical Properties Of Nanostructured Metallic Thin Films, Mo Ahoujja, Piyush Shah, Andrew Saragan, Said Elhamri, Elena A. Guliants
Electrical and Computer Engineering Faculty Publications
High surface area, porous, metallic (Ti, Cr) nanorod thin ¯lms with columnar microstructure can be deposited using conventional physical vapor deposition technique of E-beam evaporation. The technique relies on the physical vapor deposition onto a static substrate oriented in a position where °ux from the source material (Ti, Cr) arrives at oblique angle. The adatoms provides geometrical shadowing which results in growth of nanorod columns in the direction of vapor source. Deposition conditions such as angle of the incoming vapor °ux, substrate temperature, surface di®usion etc. have strong in°uence on the shape and arrangement of the columnar thin ¯lms. In …
Support Vector Machine-Based Short-Term Wind Power Forecasting,
2011
University of Nebraska-Lincoln
Support Vector Machine-Based Short-Term Wind Power Forecasting, Jianwu Zeng, Wei Qiao
Department of Electrical and Computer Engineering: Faculty Publications
This paper proposes a support vector machine (SVM)-based statistical model for wind power forecasting (WPF). Instead of predicting wind power directly, the proposed model first predicts the wind speed, which is then used to predict the wind power by using the power-wind speed characteristics of the wind turbine generators. Simulation studies are carried out to validate the proposed model for very short-term and short-term WPF by using the data obtained from the National Renewable Energy Laboratory (NREL). Results show that the proposed model is accurate for very short-term and short-term WPF and outperforms the persistence model as well as the …
Led Spotlight,
2011
California Polytechnic State University - San Luis Obispo
Led Spotlight, Eric Toussaint
Electrical Engineering
This report details the development and construction of an LED spotlight useable in a theatrical or architectural setting. In depth background information, initial design concepts, lighting instrument specifications, assembly, testing, and conclusions from results are highlighted in this document. Project goals include efforts to support more energy efficient lighting in the arts and general lighting applications and a decrease in overall costs for energy used in all dramatic and architectural lighting applications.
A Faceted Magnetron Concept Using Field Emission Cathodes,
2011
Boise State University
A Faceted Magnetron Concept Using Field Emission Cathodes, Jim Browning, Jack Watrous
Electrical and Computer Engineering Faculty Publications and Presentations
A magnetron concept using field emission cathodes has been modeled with the Air Force Research Laboratory particle-in-cell code ICEPIC and the 2D particle trajectory simulation Lorentz2E. In this approach, field emitters are used to provide a distributed cathode in place of a traditional thermionic cathode. The emitters are placed below the interaction space in a shielded structure. The cathode is comprised of facet plates with slits to protect the emitters. Simulation of an L-band rising sun magnetron shows that the faceted magnetron will oscillate using both five and ten facet cathodes. The startup times are very similar to that of …
A Study Into The Use Of Microprocessor Relays For Motor Operated Valve (Mov) Electrical Protection In Nuclear Power Plants,
2011
California Polytechnic State University, San Luis Obispo
A Study Into The Use Of Microprocessor Relays For Motor Operated Valve (Mov) Electrical Protection In Nuclear Power Plants, James Andrew Tuccillo
Master's Theses
Motor Operated Valves (MOVs) are electro-mechanical components used to isolate, divert, or introduce fluid flow. The use of microprocessor relays for actuator motor electrical protection within nuclear power plants is the focus of this thesis and is implemented by providing a new and enhanced protection scheme that provides the adequate conservatism necessary to ensure valve operation while still maintaining electrical safety and continued operational availability. The comprehensive protection scheme is designed around an advanced microprocessor relay that has the ability to simulate the thermal overload conditions of a motor operating into a destructive thermal region. Through laboratory testing, the validity …
Correlations Of Capacitance-Voltage Hysteresis With Thin-Film Cdte Solar Cell Performance During Accelerated Lifetime Testing,
2011
National Renewable Energy Laboratory
Correlations Of Capacitance-Voltage Hysteresis With Thin-Film Cdte Solar Cell Performance During Accelerated Lifetime Testing, David S. Albin, Joseph A. Del Cueto
Publications (E)
In this paper we present the correlation of CdTe solar cell performance with capacitance-voltage hysteresis, defined presently as the difference in capacitance measured at zero-volt bias when collecting such data with different pre-measurement bias conditions. These correlations were obtained on CdTe cells stressed under conditions of 1-sun illumination, open-circuit bias, and an acceleration temperature of approximately 100 ºC.
Use Of 2nd And 3rd Level Correlation Analysis For Studying Degradation In Polycrystalline Thin-Film Solar Cells,
2011
National Renewable Energy Laboratory
Use Of 2nd And 3rd Level Correlation Analysis For Studying Degradation In Polycrystalline Thin-Film Solar Cells, David S. Albin, Joseph A. Del Cueto, S. H. Demtsu, S. Bansal
Publications (E)
The correlation of stress-induced changes in the performance of laboratory-made CdTe solar cells with various 2nd and 3rd level metrics is discussed. The overall behavior of aggregated data showing how cell efficiency changes as a function of open-circuit voltage (Voc), shortcircuit current density (Jsc), and fill factor (FF) is explained using a two-diode, PSpice model in which degradation is simulated by systematically changing model parameters. FF shows the highest correlation with performance during stress, and is subsequently shown to be most affected by shunt resistance, recombination and in some cases voltage-dependent collection. Large decreases …
Effect Of Hysteresis On Measurements Of Thin-Film Cell Performance,
2011
National Renewable Energy Laboratory
Effect Of Hysteresis On Measurements Of Thin-Film Cell Performance, David S. Albin, Joseph A. Del Cueto
Publications (E)
Transient or hysteresis effects in polycrystalline thin film CdS/CdTe cells are a function of pre-measurement voltage bias and whether Cu is introduced as an intentional dopant during back contact fabrication. When Cu is added, the current-density (J) vs. voltage (V) measurements performed in a reverse-to-forward voltage direction will yield higher open-circuit voltage (Voc), up to 10 mV, and smaller short-circuit current density (Jsc), by up to 2 mA/cm2, relative to scanning voltage in a forward-to-reverse direction. The variation at the maximum power point, Pmax, is however small. The resulting variation in FF can be …
