| Analysis of Expedient Field Decontamination Methods for the XMX/2L-MIL High-Volume Aerosol Sampler |
Dec-2009 |
72 pages |
| Authors:
Brandon C LaRoche; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
|
 | The XMX/2L-MIL is a high volume air sampler used by the Air Force Bioenvironmental Engineering community to collect biological aerosols. Without a verified decontamination technique, however, the XMX cannot be used effectively. The objective of this study is to evaluate several proposed methods for expedient field decontamination of the XMX. This study centers on the inactivation of Bacillus atrophaeus spores and vegetative Erwinia herbicola organisms from the XMX inner canister. ... |
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| Simulated E-Bomb Effects on Electronically Equipped Targets |
Sep-2009 |
126 pages |
| Authors:
Enes Yurtoglu; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF INFORMATION SCIENCES
|
| Like High Altitude Electromagnetic Pulse (HEMP), high power microwaves (HPM) produce intense energies, which may overload or damage various electrical system components such as microcircuits. This thesis investigates possible effects of a hypothetically designed HEMP-like weapon, an e-bomb, on electronically equipped target systems. The procedure to determine these possible effects is to estimate the electromagnetic coupling from first principles and simulations using a coupling model program (CEMPAT), pursuing a feasible ... |
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| Laser Speckle and Atmospheric Scintillation Dependence on Laser Spectral Bandwidth: POSTPRINT |
01-Jun-2009 |
8 pages |
| Authors:
David Dayton; John St Gonglewski; Chad Arnauld; APPLIED TECHNOLOGY ASSOCIATES INC ALBUQUERQUE NM
|
| Recent advances in low-cost high power diode lasers have made available a new type of illuminator source for LADAR remote sensing systems. These sources tend to be smaller more rugged, and have better power conversion efficiency than more conventional pumped crystal solid state lasers. They can be run in short pulse, or long pulse modes with pulse repetitions from DC to 10s of kilohertz. Although they don't have large optical ... |
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| Terahertz Quantum Cascade Structures Using Step Wells And Longitudinal Optical-Phonon Scattering |
Jun-2009 |
129 pages |
| Authors:
Will Freeman; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Electron transport properties of terahertz (THz) longitudinal optical (LO)-phonon quantum cascade (QC) structures were modeled, in order to investigate high gain quantum cascade laser (QCL) structures. A new structure, a step well QC structure, was proposed. Under such an arrangement, there are three main energy levels within the step well, where the transition from the upper state to the middle state is at the THz radiative spacing and the transition ... |
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| A Computational Study of the Energy Dissipation Through an Acrylic Target Impacted by Various Size FSP |
Jun-2009 |
14 pages |
| Authors:
C G Fountzoulas; J M Sands; P G Dehmer; J H Yu; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
|
| Recent advances in the numerical techniques, higher computing power and materials model have allowed the accurate simulation of the ballistic impact into monolithic and multi-layer transparent armor configurations. In the current effort, the velocity profile during the ballistic impact of 0.22-cal and 0.15-cal fragment simulating projectiles (FSP) into a polymethyl-methacrylate (PMMA) target, which was a Plexiglas G manufactured by Atofina Chemicals was simulated using the ANSYS/AUTODYN commercial software. Our successful ... |
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| Directed Energy Weapons - Are We There Yet? The Future of DEW Systems and Barriers to Success |
May-2009 |
21 pages |
| Authors:
Elihu Zimet; Christopher Mann; NATIONAL DEFENSE UNIV WASHINGTON DC CENTER FOR TECHNOLOGY AND NATIONAL SECURITY POLICY
|
| The purpose of this paper is to examine the barriers to deployment listed above and suggest a strategy for an initial deployment that addresses these issues. This strategy will focus on current high-priority threats against which DEW would provide the best alternative for the military. |
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| Wall-Plug Efficiencies of High-Power Free Electron Lasers Employing Energy Recovery Linacs |
23-Apr-2009 |
28 pages |
| Authors:
Phillip Sprangle; Joseph Penano; Bahman Hafizi; Ilan Ben-Zvi; NAVAL RESEARCH LAB WASHINGTON DC BEAM PHYSICS BRANCH
|
| In a high average power free electron laser (FEL) the wall-plug efficiency is of critical importance in determining the size, complexity and cost of the overall system. The wall-plug efficiency for the FEL oscillator and amplifier (uniform and tapered wiggler) are strongly dependent on the energy recovery process. A theoretical model for electron beam dynamics in the energy recovery linac is derived and applied to the acceleration and de-acceleration of ... |
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| Electron Multipactor: Theory Review, Comparison and Modeling of Mitigation Techniques in ICEPIC |
Mar-2009 |
117 pages |
| Authors:
Neil Rogers; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
|
| Mitigation approaches for single surface multipactor at dielectric windows are investigated using Particle-In-Cell (PIC) simulations. Initially baseline susceptibility diagrams are constructed analytically and compared with self-consistent, dynamic system trajectories. The power deposited on the surface of a dielectric window in an HPM system is considered using three different methods and the results of PIC simulations. Geometric mitigation is then considered by varying the window orientation with respect to the HPM ... |
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| Production and Characterization of High Repetition Rate Terahertz Radiation in Femtosecond-Laser-Induced Air Plasma |
Mar-2009 |
79 pages |
| Authors:
Michael L Dexter; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
|
| The purpose of this research was to produce and characterize high repetition rate terahertz radiation in ionized air plasma. An 800 nanometer, 50 femtosecond, 0.35 Watt, 40 KHz, pulsed Ti:Sapphire laser system was used as the source infrared beam. This beam was focused onto a second harmonic generation crystal to produce a collinear, perpendicularly polarized secondary beam at 400 nm. After realigning the polarization of the fundamental to the second ... |
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| Evaluation of Saft Ultra High Power Lithium Ion Cells (VL5U) |
Feb-2009 |
24 pages |
| Authors:
Sonya Gargies; Jeff Read; Wishvender Behl; Wesley Tipton; Thomas Salem; Donald Porschet; Jan L Allen; Jeff Wolfenstine; Kang Xu; T R Jow; ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE
|
| We evaluated Saft Ultra High Power (UHP) cells (Saft designation VL5U) to determine their rate capability, low temperature performance, storage, and cycle life. The energy and power density at 5 A (1C) were 45 Wh/kg and 55 W/kg, respectively; at 1000 A (200C) were 25 Wh/kg and 10 kW/kg, respectively; and at a 500 A rate, the energy densities were 35, 29, and 29 Wh/kg at 20, -20, and -40 ... |
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| Coherent Structures and Chaos Control in High-Power Microwave and Charged-Particle Beam Devices |
31-Jan-2009 |
|
| Authors:
Chiping Chen; MASSACHUSETTS INST OF TECH CAMBRIDGE
|
 | This report summarizes research results obtained under the auspices of Air Force Office of Scientific Research, Grant No. FA9550-06-1-0269. In particular, we conducted vigorous theoretical and computational investigations of coherent structures and chaos in a wide range of intense electron beam plasmas relevant to the development of high-power microwave and particle-beam devices for directed energy applications. The research accomplishments includes: a) development of a small-signal theory of magnetrons, b) discovery ... |
|
| A Megawatt Power Module for Ship Service - Supplement. Volume 2: MatLab Simulink Simulation User's Manual |
Jan-2009 |
66 pages |
| Authors:
John D Herbst; Angelo L Gattozzi; Robert E Hebner; TEXAS UNIV AT AUSTIN CENTER FOR ELECTROMECHANICS
|
| This report is Volume 2 of a three-volume Final Report on ONR Contract N00014-07-C-0361. Activities documented in this report were performed as a supplement to ONR Grant N00014-06-01-0886. The two programs address the use of energy storage and high speed power generation to reduce fuel consumption of DDG-51 Arleigh Burke class ship service generation system by improving efficiency and permitting safe operation on one gas turbine generator set. In the ... |
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| Propulsion and Power Rapid Response Research and Development Support: Fundamental Science Investigations for Propulsion and Power Systems |
Jan-2009 |
236 pages |
| Authors:
Donald B Hanson; UNIVERSAL TECHNOLOGY CORP DAYTON OH
|
| Research was conducted for the Propulsion Directorate's research and development efforts in core technology areas for turbine engines, hypersonics, and aerospace power. Experimental and theoretical research was conducted in the technical disciplines of fuels and combustion; mechanical subsystems and life management; aerodynamics; aerospace power systems including applied and high temperature superconductivity, physics of electrical discharges, applied atomic and molecular spectroscopy, thermophysics and high temperature dielectric materials, thermal nanofluids for heat ... |
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| Test of High Power Laser Diode Protection Circuitry Designed and Built by Science Research Laboratories |
Dec-2008 |
24 pages |
| Authors:
Jeffrey O White; Robert Dibiano; ARMY RESEARCH LAB ADELPHI MD
|
| High power laser diodes have important military applications, particularly for material processing, and for pumping solid state lasers. The latter in turn can be used for neutralizing explosives, intercepting rockets, missiles, mortar shells, etc. The Joint High Power Solid State Laser program makes exclusive use of laser diode pumping. Science Research Laboratories, Inc. (SRL) has developed electronic circuitry to extend the lifetime and/or output power of high power laser diodes. ... |
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| Propulsion and Power Rapid Response R&D Support Delivery Order 0041: Power Dense Solid Oxide Fuel Cell Systems: High Performance, High Power Density Solid Oxide Fuel Cells - Materials and Load Control |
Dec-2008 |
52 pages |
| Authors:
Stephen W Sofie; Steven R Shaw; Peter A Lindahl; Lee H Spangler; MONTANA STATE UNIV BOZEMAN
|
| High Performance, High Power Density Solid Oxide Fuel Cells: Materials: The current geometry and materials set of the state-of-the-art anode supported cell (ASC) yields several deficiencies that limit the performance and robustness of the cell/stack under demanding aero based operational requirements. These deficiencies are embodied in poor gas transport through mechanically strong anodes, the limited use of cerium oxide in the anode due to unfavorable thermal expansion, and the poor ... |
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| New Nanocrystalline Core Performance Versus Finemet(Registered) for High-power Inductors |
Dec-2008 |
5 pages |
| Authors:
D P Urciuoli; T E Salem; ARMY RESEARCH LAB ADELPHI MD
|
| Advanced power electronic component development is critical for increasing power density for future military hybrid-electric ground vehicle systems. The design and development of compact, high-power, and high-temperature inductors for a 150 kW, DC-DC bidirectional converter is presented. The converter requires four 25 micronH inductors, each rated for continuous operation at 37.5 kW. With goals of reduced component volume and improved thermal management, inductor performance for commercially available FINEMET(Registered) FT-3M and ... |
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| Direct Methanol Fuel Cell Systems for Future Force Warriors: From Experimental and Simulations for Water and Methanol Crossover and Recycling to High Performance Fuel Cell Systems |
Dec-2008 |
9 pages |
| Authors:
Deryn Chu; Rongzhong Jiang; Scott Feldman; Joseph Kowal; Dave Schimmel; ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE
|
| To produce a high power and high energy density direct methanol fuel cell (DMFC) system, it must use neat methanol as a fuel, and water produced at the cathode must be recycled. Based on Faradic reactions for DMFC, a series of theoretical equations over the entire discharge current ranges were explored and developed to model and simulate water and methanol crossover in a DMFC stack. The performance of the DMFC ... |
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| Plastic Digital Array Beamformer Development With Integrated High Efficiency Gallium-Nitride MMICs |
Dec-2008 |
9 pages |
| Authors:
J Gregory; C Fulton; A Wegener; B Perlman; W Chappell; PURDUE UNIV LAFAYETTE IN
|
| With the advent of highly efficient wide bandgap amplifiers, there is the possibility of generating high power outputs without using expensive packaging. The goal is to create a plastic panel of integrated radiators which have limited cooling while having an output with a minimum of 25 Watts per element with efficiencies above 60% at die level. Towards this end, the development of highly efficient GaN MMICs and plastic packaging is ... |
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| Bio/Nano Electronic Devices and Sensors |
Oct-2008 |
11 pages |
| Authors:
W K Jones; FLORIDA INTERNATIONAL UNIV MIAMI DIV OF SPONSORED RESEARCH AND TRAINING
|
| This effort consists of five research thrusts: (1) Dense Memory Devices-(1)3-D magnetic recording was enhanced using patterned soft underlayers and interlayer, (2) Cold cathode microwave generator and ceramic electron multiplier-ceramic multiplier using a novel secondary electron yield materials of MgO and CNT was demonstrated as well as cooling structures based on capillary cooling.(3) CNT-based Bio-nano Sensor single walled CNT structures with FIB generated nanogaps have been used to probe single ... |
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| E-Bomb: The Key Element of the Contemporary Military-Technical Revolution |
01-Sep-2008 |
213 pages |
| Authors:
Necati Ertekin; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The contemporary military rivalry is driven mostly by the ongoing military technical revolution. In particular the weapons used on the future battlefield will play an important role in military affairs. Which weapons can play a key role in the future? Electromagnetic weapons seem to involve key elements for the future battlefield; they offer advantages over conventional weaponry by providing nonlethality the advantage of attack at the speed of light fast ... |
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| Bio-Nanotechnology Infrastructure and Technology Oriented Research |
17-Jul-2008 |
14 pages |
| Authors:
W K Jones; FLORIDA INTERNATIONAL UNIV MIAMI ADVANCED MATERIALS ENGINEERING RESEARCH INST (AMERI)
|
| FIU research concentrated in the following areas of development: nanoelectronics, bio-nanosensors, and nanomaterials, processes, and characterization. Five projects were supported: next generation information storage devices-both three-dimensional magnetic and protein-based, high power cold cathodes for microwave generators, carbon nanotube-based bio-sensors, silicon/polymer nanophotonics, and doped nanodiamonds and nanoceramic lasers for future devices. In magnetic storage devices, this work has resulted in patterned soft underlayer metallizations to localize the recording and sensitivity fields ... |
|
| Evaluation of SiC VJFET Devices for Scalable Solid-State Circuit Breakers |
MAY 2008 |
20 pages |
| Authors:
Damian P. Urciuoli; ARMY RESEARCH LAB ADELPHI MD
|
| Power electronic converters functioning as components in high power systems, such as those of hybrid military ground vehicles require fast fault isolation, and in most cases benefit additionally from bi-directional fault isolation. To prevent converter damage or failure, fault current interrupt speeds in the hundreds of microseconds to few millisecond range are necessary. Presently used mechanical contractors do not provide adequate actuation speeds, and suffer severe degradation during repeated fault ... |
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| The Role of Modeling and Simulation in the Evaluation of FCS: OneSAF, NETS, and DETES |
09-Apr-2008 |
10 pages |
| Authors:
Robert Gray; Michael Thurston; Jerry Wightman; Donna Smoot; Jonathan Morrow-Jones; Lindsay Samora; PRODUCT MANAGER FUTURE COMBAT SYSTEMS BRIGADE COMBAT TEAM FORT MONMOUTH NJ
|
| MOTIVATION for M&S: FCS is a system-of-systems (SoS); Evaluation required at SoS level; Evaluation relies on modeling and simulation; Response to environment stresses need to be represented in simulation: Initial Nuclear Radiation (INR) effects (Prompt, secondary, and delayed gammas - Prompt and delayed neutrons) EM effects (High altitude electromagnetic pulse (HEMP) - High powered Microwaves (HPM) - Near lightning strikes (LEMP). |
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| Measurements of Secondary Electron Yield from Materials with Application to Depressed Collectors |
04 APR 2008 |
41 pages |
| Authors:
Edl Schamiloglu; Mark Gilmore; NEW MEXICO UNIV ALBUQUERQUE DEPT OF ELECTRICAL ENGINEERING AND COMPUTER SCIENCE
|
| This final technical report reviews the research activities during the period of this grant, emphasizing the final year. The key finding of our study is that the total incident electron dose is a critical parameter affecting secondary electron emission (SEE). A completely automated experimental set-up was implemented that allowed for measurement of secondary electron yield (SEY) as a function of beam energy, angle of incidence of primary electrons, electron dose, ... |
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| Numerical Models of Mode Interaction in Gyrotrons: Capabilities and Limitations |
Apr-2008 |
3 pages |
| Authors:
Baruch Levush; Antonsen; Thomas M Jr; Igor A Chernyavskiy; Alexander N Vlasov; Gregory S Nusinovich; James A McDonald; SCIENCE APPLICATIONS INTERNATIONAL CORP MCLEAN VA
|
| Mode interaction in cylindrical and coaxial gyrotrons are simulated by gyrotron design code MAGY. Effectiveness and limitations of MAGY models for mode interaction in gyrotrons operating at higher order modes are discussed. Similarities and differences in mode competition process in cylindrical and coaxial gyrotrons are studied and discussed. |
|
| Enhanced Field Emission Properties from Carbon Nanotube Emitters Grown on NiCr Alloy Surfaces with Grain Boundary Effect |
Apr-2008 |
|
| Authors:
Setha Yim; Richiro Ohta; Jessie L Killian; Nathaniel B Zuckerman; Emily Allen; Cattien V Nguyen; ELORET CORP MOFFETT FIELD CA NASA AMES RESEARCH CENTER
|
| Carbon nanotubes (CNTs) are known to have exceptional field emission properties such as low turn-on voltage and high current density. Nilsson et al. reported that field emission properties depend highly on the density of the CNT films. The CNTs must have low density in order to minimize electrostatic field screening from neighboring nanotubes. At the same time, the CNT films must have a high number of emitting sites to achieve ... |
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| Pendeo-Epitaxy Process Optimization of GaN for Novel Devices Applications |
APR 2008 |
22 pages |
| Authors:
Michael A. Derenge; Tsvetanka S. Zheleva; Kenneth A. Jones; Pankaj B. Shah; Daniel Ewing; J. Molstad; Unchul Lee; Matthew H. Ervin; David N. Stepp; ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE
|
| A relatively new class of materials known as wide bandgap materials and the corresponding devices fabricated from them have extremely useful characteristics for high temperature, high-frequency, high-power applications in numerous army systems and components. However the technology for these new materials is not mature enough and these materials contain various types of structural defects in high concentrations. It is well known that structural defects degrade the performance of the electronic ... |
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| High Altitude Electromagnetic Pulse (HEMP) and High Power Microwave (HPM) Devices: Threat Assessments |
26 MAR 2008 |
|
| Authors:
Clay Wilson; LIBRARY OF CONGRESS WASHINGTON DC CONGRESSIONAL RESEARCH SERVICE
|
| Electromagnetic Pulse (EMP) is an instantaneous, intense energy field that can overload or disrupt at a distance numerous electrical systems and high technology microcircuits, which are especially sensitive to power surges. A large scale EMP effect can be produced by a single nuclear explosion detonated high in the atmosphere. This method is referred to as High-Altitude EMP (HEMP). A similar, smaller-scale EMP effect can be created using non-nuclear devices with ... |
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| High-Efficiency Helical Coil Electromagnetic Launcher and High Power Hall-Effect Switch |
29 FEB 2008 |
41 pages |
| Authors:
Thomas G. Engel; William C. Nunnally; John M. Gahl; MISSOURI UNIV-COLUMBIA COLL OF ENGINEERING
|
| Efficiency and scaling relationships for DC (i.e., non-induction) constant inductance gradient electromagnetic launchers are presented and discussed. Expressions for electromagnetic force, efficiency, back-voltage, and kinetic power are derived and given in terms of electrical circuit parameters. Launcher efficiency is shown to be a simple function of armature velocity and the launcher's characteristic velocity. The characteristic velocity characterizes the launcher and is the product of two new parameters; the mode constant ... |
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| Reliability of Next Generation Power Electronics Packaging Under Concurrent Vibration, Thermal and High Power Loads |
FEB 2008 |
273 pages |
| Authors:
Cemal Basaran; STATE UNIV OF NEW YORK
|
| This final report presents a study on predicting reliability of next generation power electronics packaging, under high power loads. The study entails computational simulation modeling of power electronics packaging under high current density, high temperature gradient, high temperature and mechanical loads. Computer simulations are used for various scenarios to predict life time to failure and predictions are compared against actual experimental field data to validate the models. |
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| Wireless Cooperative Networks: Self-Configuration and Optimization |
10 JAN 2008 |
5 pages |
| Authors:
Liuqing Yang; Roslyn S. Oleson; FLORIDA UNIV GAINESVILLE OFFICE OF RESEARCH
|
| In wireless sensor networks, relay transmissions can enable cooperative diversity by forming virtual antenna arrays. The optimum resource allocation in such systems is critical to enhance their error rate performance and energy efficiency. Existing work often focus on the optimization of the energy allocation among the source and relay nodes. This is not only undesirable from the relays' point of view especially when they are required to transmit at high ... |
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| Functional Test Results of a High Power Patch Array Antenna |
JAN 2008 |
30 pages |
| Authors:
Canh Ly; ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE
|
| Mechanical and electrical test results of a high power two-patch array antenna [ARL Invention pending ARL-07-18, Ly, et al.] are presented. The mechanical test was run for 55 minutes for each axis of the antenna. The electrical test was conducted using a high power RF source (>1 KW) with single and two-patch array antennas. Although the first mechanical test results indicated that the screws of the antenna cover are loosened ... |
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| Thermal Simulation of Four Die-Attach Materials |
JAN 2008 |
18 pages |
| Authors:
Gregory K. Ovrebo; ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE
|
| We performed a time-dependent simulation of thermal transfer in a circuit board, comparing the effects of using four different die-attach materials with high-power silicon carbide diodes. This simulation attempted to reproduce the results of a laboratory experiment in which thermal measurements were made of circuit boards under a time-varying load. |
|
| Helicopter Magnetometer Platform Based on Compact Induction Sensors |
12-Dec-2007 |
30 pages |
| Authors:
Yongming Zhang; QUASAR FEDERAL SYSTEMS INC SAN DIEGO CA
|
| In this SERDP SEED project, QUASAR Federal Systems (QFS) carried out a proof-of-concept study for airborne UXO detection using AC induction sensor (IS) magnetometers. Current airborne UXO detection is dominated by Cs-vapor, DC total field magnetometers. These DC magnetometers are expensive, consume high power, and do not provide enough information about the shape or orientation of the target. QFS has recently developed a compact IS magnetometer with equivalent sensitivity to ... |
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| Simulation of Air Flow Through a Test Chamber |
DEC 2007 |
14 pages |
| Authors:
Gregory K. Ovrebo; ARMY RESEARCH LAB ADELPHI MD
|
| Computer simulation was used to investigate the flow of forced air through a test chamber used to measure heat dissipated by an inductor. Cosmos FloWorks simulations provide a qualitative picture of the air stream passing through the chamber, as well as calculations of air velocity at the chamber outlet port. These results provide a correction factor for measurements of power dissipation in high-power electric components. |
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| Comparison of Gallium Nitride High Electron Mobility Transistors Modeling in Two and Three Dimensions |
DEC 2007 |
77 pages |
| Authors:
William A. Gibson; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| This thesis looks at modeling Gallium Nitride (GaN) High Electron Mobility Transistor (HEMT) Semiconductors. The GaN device has potential future military use in the high power and high frequency operation replacing costly millimeter wave tubes This would affect military radar systems, electronic surveillance systems, communications systems and high voltage power systems by providing smaller and more reliable devices to drive operation This thesis looks at using diamond substrate to improve ... |
|
| Solid-State Nuclear Magnetic Resonance Investigations of Microwave Tube Cathode Structure |
30 NOV 2007 |
6 pages |
| Authors:
K. A. Smith; NEW MEXICO UNIV ALBUQUERQUE OFFICE OF RESEARCH SERVICES
|
| The objective of this work was to determine if Solid-State Nuclear Magnetic Resonance (NMR) would be able to determine what chemical or structural changes occur during treatment of carbon fibers by CsI, and during operation of treated cathodes. It was known that CsI treated carbon fibers are superior to either solid CsI or untreated fibers when used as cathodes for high power microwave production. For C-13 NMR, probe background was ... |
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| Mode Locking of Quantum Cascade Lasers |
09 NOV 2007 |
42 pages |
| Authors:
Federico Capasso; Franz X. Kaertner; HARVARD UNIV CAMBRIDGE MA SCHOOL OF ENGINEERING AND APPLIED SCIENCES
|
| A theoretical and experimental study of multimode operation regimes in quantum cascade lasers (QCLs) is presented. It is shown that the fast gain recovery of QCLs promotes two multimode regimes in QCLs: One is spatial hole burning (SHB), and the other one is related to the Risken-Nummedal-Graham-Haken (RNGH) instability predicted in the sixties. A model that can account for coherent phenomena, a saturable absorber and SHB is developed and studied ... |
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| Compressed Scattering Matrices and Fast Direct Solvers |
18 OCT 2007 |
9 pages |
| Authors:
Vladimir Rokhlin; YALE UNIV NEW HAVEN CT GRANT AND CONTRACT ADMINISTRATION
|
| New direct and analytically precondidoned frequency and time domain integral equation solvers have been developed. First mechanisms for compressing scattering matrices in static and relatively low-frequency environments will be pursued and used in the construction of direct frequency domain integral equation solvers applicable to objects roughly 40 wavelengths in size. Second hierarchical and Calderon preconditioned time-domain integral equation solvers were developed. These solvers remain repidly convergent and stable even when ... |
|
| Hydrothermal Synthesis and Growth of Ti:Sapphire(Ti3+:Al2O3) Laser Crystals |
01 OCT 2007 |
18 pages |
| Authors:
David Bliss; Michael Callahan; Buguo Wang; AIR FORCE RESEARCH LAB HANSCOM AFB MA
|
| Titanium-doped sapphire (Ti3+:Al2O3) crystals for high-power tunable lasers are presently in commercial production by growth from the melt. However, it is difficult to grow homogeneous crystals from the melt with uniform doping concentration because of the impurity segregation effect and more importantly, trivalent titanium instability. Hydrothermal synthesis has several advantages over traditional melt techniques. Here we report the growth of Ti3+:Al2O3 crystals by the hydrothermal technique for the first time ... |
|
| Novel Designs and Coupling Schemes for Affordable High Energy Laser Modules |
28 SEP 2007 |
74 pages |
| Authors:
Jerome V. Moloney; Axel Schulzgen; Pavel Polynkin; Masud Mansuripur; Mahmoud Fallahi; Yoel Fink; Chiping Chen; ARIZONA UNIV BOARD OF REGENTS TUCSON
|
| This multi-disciplinary research effort developed new classes of compact, highly-doped Er/Yb phosphate-doped glass fibers as high power, low noise single wavelength, single mode oscillators. Three world record powers in low-noise, single frequency laser oscillators at the eyesafe wavelength of 1.55 micrometers were reported. The project vertically integrated fabrication, testing, and optimization of all components necessary for manufacturing of fiber laser units including highly doped specialty glasses, fiber preforms, fiber drawing ... |
|
| Survey of Commercial Small Lithium Polymer Batteries |
19 SEP 2007 |
25 pages |
| Authors:
Arnold M. Stux; Karen Swider-Lyons; NAVAL RESEARCH LAB WASHINGTON DC
|
| The power and energy of small 1 to 5 g lithium polymer batteries is improving significantly, with a push from the toy and hobby markets. This report characterizes the power and energy of several small batteries from Atomic Workshop, Full River, Kokam, and TOBN, presenting discharge curves as a function of C-rates. The 130 mAh Atomic Workshop batteries are rated to a specific power of nearly 2400 W/kg, and energies ... |
|
| Consolidation of Al2O3 Nano-Ceramic Powders for High Power Micro-Wave Window |
19 SEP 2007 |
11 pages |
| Authors:
Whung W. Kim; KOREA ATOMIC ENERGY RESEARCH INST DAEJEON (SOUTH KOREA) NUCLEAR MATERIALS TECHNOLOGY DEVELOPMENT TEAM
|
| In this study nanostructured a-Al2O3 ceramics have been fabricated by the combined application of magnetic pulsed compaction (MPC) and spark plasma sintering (SPS), and their density and hardness properties were investigated. The combined application of the MPC and the SPS produced very fine and dense alumina ceramics. The measured grain size was 330nm being slightly higher than the size of the starting powder (200-300nm), suggesting a very low degree of ... |
|
| Development of THz Fiber Lasers |
12-Sep-2007 |
8 pages |
| Authors:
Xi-Cheng Zhang; Albert Redo-Sanchez; Gernot S Pomrenke; RENSSELAER POLYTECHNIC INST TROY NY
|
| There is no Current commercially available THz fiber Laser on the market, and there is no any report successful demonstration of THz fiber lasers in literatures. Our DURIP project is to develop a THz fiber Laser on a novel photonic crystal fiber technique. The THz fiber laser has several important characteristics; sm portability, room temperature operation, and high output power. ALL provide advantages over current THz La a new high-power, ... |
|
| Directed-Energy Weapons: Invisible and Invincible? |
SEP 2007 |
139 pages |
| Authors:
Bayram M. Deveci; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| A military weapon is any tool used to increase the reach or power of a nation. Simply, it can be said that each era witnesses the deployment of new and powerful mass destruction weaponry. What will this century's most powerful weapon be? Directed-energy weapons, which offer advantages over conventional weapons by providing attack at the speed of light, precise targeting, rapid engagement of multiple targets, adjustable damage capacity, low operational ... |
|
| Advanced Laser and RF Plasma Sources and Diagnostics |
13-Jun-2007 |
19 pages |
| Authors:
John E Scharer; WISCONSIN UNIV-MADISON DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
|
| We have purchased and have running state-of-the-art equipment that enhances our research capabilities for efficient laser initiation and radiofrequency sustainment of plasmas and diagnostics in air, as well as near microwave windows and on cathode surfaces as part of the MURI on Nano-physics of Electron Emission and Breakdown for High Power Microwaves. |
|
| A Design Study of a C-Band Crestatron |
08 JUN 2007 |
25 pages |
| Authors:
David K. Abe; Baruch Levush; David P. Chernin; NAVAL RESEARCH LAB WASHINGTON DC VACUUM ELECTRONICS BRANCH
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| This memorandum presents a design study of a high power C-band Crestatron Amplifier. While conventional helix traveling-wave tubes (TWT's) are operated in an exponentially growing-wave mode, the Crestatron operates a "beating-wave" regime where three constant-amplitude voltage waves traveling at different phase velocities along the helix beat together to produce power gain. Although inherently lower in gain than a TWT, the Crestatron can produce high power rf over a surprisingly broad ... |
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| HVEPS Scramjet-Driven MHD Power Demonstration Test Results (Preprint) |
JUN 2007 |
32 pages |
| Authors:
J. T. Lineberry; L. Begg; J. H. Castro; Ron J. Litchford; J. M. Donohue; LYTECH LLC TULLAHOMA TN
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| The Air Force sponsored Hypersonic Vehicle Electric Power System (HVEPS) program was a research program to develop scramjet driven magnetohydrodynamic (MHD) power for an advanced high power, airborne electric power system. This program has been active for the past five years with various technical tasks being addressed that have encompassed engineering investigations of a myriad of technical issues related to airborne hypersonic MHD power system integration and operation. The integrated ... |
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| Terahertz Fiber Laser for Explosives Detection |
JUN 2007 |
12 pages |
| Authors:
Antonije Radojevic; CHARLES STARK DRAPER LAB INC CAMBRIDGE MA
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| The C.S. Draper Laboratory, with 30 years of experience in instrument and sensor research and development, and the University of Massachusetts Terahertz Laboratory, with 15 years of research in the development terahertz receivers and focal plane arrays, propose to develop and characterize a fundamentally new method for generating terahertz radiation. Our approach will enable the development of a class of high power (>=100 mW), portable, coherent, terahertz radiation source devices ... |
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| Remote Measurement of High Temperatures in the Presence of a Strong Magnetic Field |
07 MAY 2007 |
50 pages |
| Authors:
Scott F. Lord; NAVAL ACADEMY ANNAPOLIS MD
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| The environment inside a railgun makes conventional temperature sensing techniques ineffective. Large time-varying magnetic fields induce noise into sensors with electrical connections. The high rate of change of temperature requires a fast thermal response and a fast sampling rate. Finally, the intense heat generated requires a sensor that is thermally stable over a large range of temperatures. To overcome such environmental challenges, this project utilized an interferometric technique where the ... |
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Reports by Keyword(s)
HIGH POWER
