| Continued Optical Sensor Operations in a Laser Environment |
Oct 2012 |
37 pages |
| Authors:
William J Diehl; AIR WAR COLL MAXWELL AFB AL
|
 | The United States and other nations are developing laser (i.e., light amplification by stimulated emission of radiation) applications, including high-energy lasers (HEL) and low-energy lasers (LEL). HELs will likely have military applications in ballistic missile defense (BMD), counter-air, counter-space, and counter-intelligence, surveillance, and reconnaissance (ISR). However, HEL applications will be slow to proliferate to many potential adversaries due to their high cost and technical complexity. LELs will be developed as ... |
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| Improved Round Trip Efficiency for Regenerative Fuel Cell Systems |
11 May 2012 |
23 pages |
| Authors:
Katherine E Ayers; PROTON ENERGY SYSTEMS INC WALLINGFORD CT
|
| In developing technology for air independent undersea vehicle missions, a ground-test breadboard system was adapted and utilized to prove advanced components that enable closed-loop, zero emission, low signature energy storage. The system utilizes proton exchange membrane (PEM) fuel cell and electrolysis technology with proven commercial reliability, and a balance-of-plant primarily consisting of commercial-off-the-shelf (COTS) components. Initial durability testing measured the magnitude of reactant loss to the ambient atmosphere, before replacing ... |
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| Endwall Loss and Mixing Analysis of a High Lift Low Pressure Turbine Cascade (Preprint) |
May 2012 |
14 pages |
| Authors:
M E Lyall; Paul I King; Rolf Sondergaard; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH PROPULSION DIRECTORATE
|
| A high lift LPT profile designated L2A is used as a test bed for studying the origin of endwall mixing loss and the role of vortical structures in loss development. It is shown analytically and experimentally that the mixing forces within the endwall wake can be decoupled into either mean flow or turbulent forces, and can be further classified as either reversible or irreversible. Among the irreversible forces, mean flow ... |
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| Screening Adhesively Bonded Single-Lap-Joint Testing Results Using Nonlinear Calculation Parameters |
Mar 2012 |
8 pages |
| Authors:
Robert Jensen; Jonathan Kaufman; Wendy K Chaney; Benjamin Henrie; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
|
| Adhesive needs for Army ground vehicles are driven by high strength and high damage tolerance. These basic materials properties requirements do not coincide with traditional aerospace adhesive demands of high strength and high stiffness, which are derived from linear-elastic stress-strain behavior and very little energy absorption. High damage tolerance requires significant energy absorption and the accompanying nonlinear stress-strain response. Therefore, the simplified approach of defining adhesive bond strength as peak ... |
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| Incompletely-Condensed Fluoroalkyl Silsesquioxanes and Derivatives: Precursors for Low Surface Energy Materials (Preprint) |
13 Sep 2011 |
17 pages |
| Authors:
Sean M Ramirez; Raymond Campos; Timothy S Haddard; Yvonne J Diaz; Rebecca L Stone; Joseph M Mabry; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| A novel synthetic method was developed for the controlled functionalization of Fluorinated Polyhedral Oligomeric SilSesquioxanes (F-POSS), which are useful as low surface energy materials for superhydrophobic and oleophobic materials. Utilizing triflic acid, open-cage compounds were created and then reacted with a variety of dichlorosilanes to produce functional F-POSS structures possessing alkyl, aryl, and acrylate based moieties. The crystal structure for an endo,endo disilanol F-POSS compound was determined by single crystal ... |
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| System Size and Energy Dependence on Strangeness Production in 22 GeV Cu+Cu Collisions at RHIC |
10 May 2011 |
70 pages |
| Authors:
Grant A Morgan; NAVAL ACADEMY ANNAPOLIS MD
|
| The Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory collides different ions at a wide variety of energies in order to study the properties of nuclear matter in extreme conditions. Beams of ions are sent around an accelerator ring at relativistic speeds approaching the speed of light before they meet in an extremely high temperature collision. The Solenoidal Tracker at RHIC (STAR) experiment exists to examine and identify the ... |
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| Device Quality Sb-Based Compound Semiconductor Surface: A Comparative Study of Chemical Cleaning |
Jan 2011 |
8 pages |
| Authors:
Aneesh Nainani; Yun Sun; Toshifumi Irisawa; Ze Yuan; Masaharu Kobayashi; Piero Pianetta; Brian R Bennett; J B Boos; Krishna C Saraswat; STANFORD UNIV CA DEPT OF ELECTRICAL ENGINEERING
|
| We have studied the surface cleaning of Sb-based compound semiconductors using HF, NH4OH, and HCl cleans and the metal oxide semiconductor (MOS) capacitors fabricated subsequently. GaSb, InGaSb, and AlGaSb surfaces are investigated using low-energy radiation from the synchrotron. Capacitance voltage (C V) and photoluminescence measurements are carried out on capacitors made with Al2O3 from atomic layer deposition and corroborated with the results from synchrotron spectroscopy. Excellent C V characteristics with ... |
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| Quartz Crystal Microbalance Based System for High-Sensitivity Differential Sputter Yield Measurements (Preprint) |
20-Aug-2009 |
17 pages |
| Authors:
J L Topper; B Rubin; C C Farnell; A P Yalin; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| We present a quartz crystal microbalance (QCM) based system for high sensitivity differential sputter yield measurements of different target materials due to ion bombardment. The differential sputter yields can be integrated to find total yields. Possible ion beam conditions include ion energies in the range of 30-350 eV and incidence angles of 0-70o from normal. A four-grid ion optics system is used to achieve a collimated ion beam at low ... |
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| Investigation of Low Discharge Voltage Hall Thruster Operating Modes and Ionization Processes |
14-Aug-2009 |
45 pages |
| Authors:
Daniel L Brown; Alec D Gallimore; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| A study of low discharge voltage Hall thruster operation revealed the existence of two operating regimes. Small variations in cathode flow fraction and magnetic field resulted in sharp changes in discharge current with constant thrust, corresponding to a visible change in the jet-mode plume structure. The phenomenon is characterized with a systematic map of thruster operation for discharge voltages ranging from 100 - 120 V, anode flow rates from 10 ... |
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| A Laser-Based Sensor for Ambient Detection of RDX and TNT |
Dec-2008 |
6 pages |
| Authors:
Stephen D Roberson; Rosario C Sausa; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| We detect trace residues of RDX and TNT by surface photofragmentation - fragment detection in real time at ambient conditions. An infrared or visible laser generates signature, NO molecular fragments, and a second, low energy, ultraviolet laser facilitates their detection by resonance enhanced multiphoton ionization. We present the effects of pump laser wavelength, laser energy, delay timing between the pump and probe beams, and analyze concentration on signal intensity. Sensitivity ... |
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| SecureCore Software Architecture: Trusted Management Layer (TML) Kernel Extension Module Interface Specification |
JAN 2008 |
20 pages |
| Authors:
David J. Shifflett; Paul C. Clark; Cynthia E. Irvine; Thuy D. Nguyen; Timothy M. Vidas; Timothy E. Levin; NAVAL POSTGRADUATE SCHOOL MONTEREY CA CENTER FOR INFORMATION SYSTEMS SECURITY STUDIES AND RESEARCH
|
| A mobile computing device has more inherent risk than desktops or most other stationary computing devices. Such mobile devices are typically carried outside of a controlled physical environment, and they must communicate over an insecure medium. The risk is even greater if the data being stored, processed, and transmitted by the mobile device is classified. The purpose of the SecureCore research project is to investigate fundamental architectural features required for ... |
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| Energy and Power Aware Computing Through Management of Computational Entropy |
JAN 2008 |
60 pages |
| Authors:
Krishna V. Palem; Mark Richards; GEORGIA INST OF TECH ATLANTA SCHOOL OF ELECTRICAL AND COMPUTER ENGINEERING
|
| With the increasing importance of computing in portable and other embedded settings, the power and energy consumed by computation has become an important consideration driving research in computer engineering and science. Historically, the study of power and energy have roots in the field of thermodynamics. The innovations that we propose in this work aim to develop a mechanism for designing algorithms that are power (energy) aware by directly working with ... |
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| SecureCore Software Architecture: Trusted Management Layer (TML) Kernel Extension Module Integration Guide |
DEC 2007 |
18 pages |
| Authors:
David J. Shifflett; Paul C. Clark; Cynthia E. Irvine; Thuy D. Nguyen; Timothy M. Vidas; Timothy E. Levin; NAVAL POSTGRADUATE SCHOOL MONTEREY CA CENTER FOR INFORMATION SYSTEMS SECURITY STUDIES AND RESEARCH
|
| A mobile computing device has more inherent risk than desktops or most other stationary computing devices. Such mobile devices are typically carried outside of a controlled physical environment, and they must communicate over an insecure medium. The risk is even greater if the data being stored, processed, and transmitted by the mobile device is classified. The purpose of the SecureCore research project is to investigate fundamental architectural features required for ... |
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| ExB Measurements of a 200 W Xenon Hall Thruster (Preprint) |
28 AUG 2007 |
24 pages |
| Authors:
Jared M. Ekholm; Jr Hargus William A.; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| Angularly resolved ion species fractions of Xe+1, Xe+2, and Xe+3 in a low power xenon Hall thruster Busek BHT-200 plume were measured using an ExB probe under a variety of thruster operating conditions and background pressures. The thruster was operated at several operating conditions by varying the anode potential of the thruster from 200 V to 325 V in 25 V increments. Measurements of the ion species fractions were made ... |
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| Geospace Plasma Dynamics: Final Report (2002-2007) |
14 AUG 2007 |
30 pages |
| Authors:
Bamandas Basu; John R. Jasperse; AIR FORCE RESEARCH LAB HANSCOM AFB MA SPACE VEHICLES DIRECTORATE
|
| Radar measurements of backscatter from plumes extending above the bottom side spread-F layer correlated well with observations of equatorial plasma bubbles in quiet conditions with lower correlation between scintillation and observations of plasma bubbles. DMSP satellites and the ROCSAT-1 satellite showed significantly fewer occurrences of plasma bubbles than expected near the west coast of South America and an east-west chain of GPS receivers confirms a steep longitudinal gradient in EPB ... |
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| Two-Photon Absorption Measurements: Establishing Reference Standards. |
08 JUN 2007 |
19 pages |
| Authors:
Marek Samoc; Anna Samoc; Paul A. Fleitz; AUSTRALIAN NATIONAL UNIV CANBERRA
|
| Two-Photon Absorption "TPA" is an important phenomenon taking place at high light intensities and consisting in simultaneous absorption of two low energy photons to generate a higher energy excited state of a material. Materials showing efficient two-photon absorption are required for a number of applications including information storage, photonic signal processing, optical power limiting, nonlinear microscopy of biological systems etc. This report contributes to the knowledge of parameters influencing the ... |
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| Cobalt Doping of Semiconducting Boron Carbide Using Cobaltocene |
MAR 2007 |
100 pages |
| Authors:
Lonnie Carlson; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH
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| The decomposition of cobaltocene and metacarborane (closo-1,7-dicarba-decaborane) under low energy electron irradiation at about 200 K results in a material with the Fermi level closer to the valence band than the material resulting from the decomposition of metacarborane alone. This indicates that cobaltocene provides a relatively p-type dopant as seen in ultraviolet photoemission spectroscopy/inverse photoemission spectroscopy. Upon warming to room temperature, however, the Fermi level shifts towards the conduction band, ... |
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| Congressional-Microwave Vacuum Electronics Power Res. Ini.) TWT Coatings Improvement Investigation |
01 FEB 2007 |
25 pages |
| Authors:
L-3 COMMUNICATIONS TORRANCE CA
|
| Gain stability has long been identified as a key attribute for successful long-term operation of both space and terrestrial helix traveling wave tubes (TWTs), whose mission life may extend to 15 or more years. Gain change associated with attenuator (carbon) thin film resistivity change has been observed for at least 30 years; however no definitive experimental evidence to support the various resistance change theories has been available. Using a modified ... |
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| Ultrahydrophobic Fluorinated Polyhedral Oligomeric Silsesquioxanes (F-POSS) (Preprint) |
25 JAN 2007 |
11 pages |
| Authors:
Joseph M. Mabry; Scott T. Iacono; Brent D. Viers; Ashwani Vij; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| Recently, significant attention has been drawn to preparing low surface energy materials inspired by naturally evolved biological systems possessing a high degree of ultrahydrophobicity. Specifically, the lotus leaf exhibits an inherent self-cleaning mechanism resulting from micron-sized waxy nodes protruding from its surface so that water is naturally repelled removing any foreign debris. This remarkable cleansing mechanism, coined the "lotus effect," has been artificially mimicked to produce materials with pronounced ultrahydrophobicity. ... |
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| A Shock-Tube-Based Facility for Impact Testing |
01-Jan-2007 |
13 pages |
| Authors:
Qi Li; Dahsin Liu; Douglas Templeton; Basavarju Raju; MICHIGAN STATE UNIV EAST LANSING DEPT OF MECHANICAL ENGINEERING
|
| Many dynamic testing techniques use gas guns as a pressure generator. The pressure generated from the gas guns is often of low velocity and low energy and has a relatively random or short duration of a uniform pressure level. This kind of pressure is not well defined and cannot be converted into other application conditions. With aims at improving experimental capability and expanding the research horizon, a shock tube was ... |
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| Progressive Failure Analysis of Thin Walled Composite Tubes Under Low Energy Impact |
2007 |
10 pages |
| Authors:
Chian-Fong Yen; Thomas Cassin; Joel Patterson; Matt Triplett; MATERIALS SCIENCES CORP FORT WASHINGTON PA
|
| Composite failure criteria have been developed for dynamic analysis of composite structures. The proposed progressive failure criteria have been integrated into an explicit dynamic analysis code for failure prediction of thin composite tubes subjected to drop weight impact tests. The results provide good correlation with experimental data for impact force histories and some critical damage modes. |
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| Branch Detonation of a Pulse Detonation Engine With Flash Vaporized JP-8 |
DEC 2006 |
99 pages |
| Authors:
John D. Slack; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING
|
| Pulse Detonation Engines (PDE) operating on liquid hydrocarbon fuels are limited to operating frequencies of 35 Hz due to long ignition times from a low energy ignition sources. This study shows ignition time of JP-8 can be nearly eliminated by igniting a thrust tube using a secondary detonation. A counter flow heat exchanger attached to a thrust tube utilized waste heat from the detonation process to heat JP-8 to supercritical ... |
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| Collision Dynamics of Rydberg Atoms and Molecules at Ultralow Energies |
31 DEC 2005 |
108 pages |
| Authors:
M. R. Flannery; GEORGIA INST OF TECH ATLANTA SCHOOL OF PHYSICS
|
| First Major Highlight: Collisional Stark Mixing at ultralow energies in Rydberg Plasmas. Atoms in high (n,l) states formed in cold Rydberg plasmas decay to the ground state in a succession of radiative transitions populating intermediate excited states. Which states are populated during cascading and with what probability can be obtained from known transition probabilities. Classical models simplify the calculation considerably, revealing the "trajectory" in nt space followed during the cascade, ... |
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| Magneto-Mechanical Response in Ni-Mn-Ga Magnetic Shape Memory Alloys |
24 AUG 2005 |
|
| Authors:
Leon M. Cheng; Rosaura Ham-Su; Shannon P. Farrell; Calvin V. Hyatt; DEFENCE RESEARCH AND DEVELOPMENT ATLANTIC DARTMOUTH (CANADA)
|
 | It is generally accepted that the large reversible, magnetic-field-induced strain observed in ferromagnetic shape memory alloys is due to the rearrangement of twin variants in the martensite by an applied magnetic field leading to an overall change of shape. The main thermodynamic driving force for twin boundary motion in the presence of a magnetic field is the high magnetocrystalline anisotropy of the low-symmetry martensitic phase. Low twin boundary energy, high ... |
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| Assessed Total and Partial Ionization Cross Sections for CF4, C2F6, C3F8, CHF3, CF3I, c-C4F8, Cl2, CCl2F2, BCl3, SF6, and Fragments of CF4 and SF6 |
08 JUN 2005 |
8 pages |
| Authors:
Loucas G. Christophorou; James K. Olthoff; NATIONAL ACADEMY OF ATHENS (GREECE)
|
| The authors recently completed an updated review, synthesis, assessment, and discussion of low-energy electron interactions with the plasma processing gases CF4, C2F6, C3F8, CHF3, CF3I, c-C4F8, Cl2, CCl2F2, BCl3, and SF6. This work, along with fundamental knowledge on electron-molecule collision processes, the definition of the various electron collision cross-sections and rate coefficients, and the experimental and theoretical methods used for their determination have been described in Christophorou and Olthoff. It ... |
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| Scintillator-Based Low-Energy Imaging Particle Spectrometer |
APR 2005 |
8 pages |
| Authors:
G. E. Galica; R. L. Coxe; R. G. Chaves; H. E. Spence; B. K. Dichter; D. L. Cooke; G. Ginet; PHYSICAL SCIENCES INC ANDOVER MA
|
| Physical Sciences Inc. (PSI), in cooperation with the Boston University Center for Space Physics, and under the sponsorship of the Air Force Research Laboratory Space Vehicle Directorate, has developed and tested a lightweight, multi-configuration sensor to monitor the space weather environment. The scintillator-based, Low-Energy Imaging Particle Spectrometer (LIPS) is ideally suited to monitoring the lower energy (20 to 2000 keV) charged particle environment responsible for deep dielectric charging. The LIPS ... |
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| Real-Time Task Scheduling for Energy-Aware Embedded Systems |
2005 |
5 pages |
| Authors:
Vishnu Swaminathan; Krishnendu Chakrabarty; DUKE UNIV DURHAM NC DEPT OF ELECTRICALAND COMPUTER ENGINEERING
|
| We present a new approach for scheduling workloads containing periodic tasks in real-time systems. The proposed approach minimizes the total energy consumed by the task set and guarantees that the deadline for every periodic task is met. As embedded software becomes a larger component of system-on-a-chip design, energy management using the operating system becomes increasingly important. We present a mixed-integer linear programming model for the NP-complete scheduling problem and solve ... |
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| Unmanned Aerial Vehicle Camera Integration |
NOV 2004 |
20 pages |
| Authors:
Ricky E. Sward; Stephen D. Cooper; AIR FORCE ACADEMY COLORADO SPRINGS CO INST FOR INFORMATION TECHNOLOGY APPLICATIONS
|
| In recent years, Unmanned Aerial Vehicles (UAVs) have provided a bird's eye view of the battlefield with onboard video cameras feeding video images back to a ground control station. This paper reports on a project conducted by members of the Air Force Academy's UAV Research Group to purchase equipment and build an integrated video capture system for a small UAV. The project was funded by a grant from the Institute ... |
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| First Observation of Four-Body Breakup in Electron Recombination: C2D5(+) |
08 OCT 2004 |
5 pages |
| Authors:
W. Geppert; A. Ehlerding; F. Hellberg; S. Kalhori; R. D. Thomas; O. Novotny; S. T. Arnold; T. M. Miller; A. A. Viggiano; STOCKHOLM UNIV (SWEDEN) INST OF PHYSICS
|
| We report the first observation of four-body breakup in electron dissociative recombination of a molecular ion: C2D5+. In an ion storage ring experiment, the branching ratio for the process C2D5(+) + e -> C2D2 + D + D + D was determined to be 13%. This means that three covalent chemical bonds are broken as a result of the action of a single electron. This is the first time a ... |
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| Trauma Induced Pain and Wound Management in Emergency Environment by Low Energy Photonic Therapy |
01 SEP 2004 |
37 pages |
| Authors:
Natasha Salansky; Anthony Galea; Norman Salansky; INTERNATIONAL MEDICAL INSTRUMENTS INC TORONTO (ONTARIO)
|
| Low Energy Photonic Therapy (LEPT) is a new non-drug, non-invasive treatment modality for acute trauma and wound healing acceleration that utilizes monochromatic light. Various monochromatic optical sources (lasers, laser diodes and light emitting diodes) are used for LEPT. LEPT can be applied immediately after trauma. LEPT is administered with a short-term goal to achieve fast resolution of symptoms (pain, swelling, and inflammation) and function improvement. In the long run, LEPT ... |
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| Analyzing, Evaluating, and Quantifying the Thermal Energy Contributions of the Passive Solar-Heating Elements Incorporated in the Design and Construction of the Plumblee Residence Located in Alamance County, NC |
AUG 2004 |
142 pages |
| Authors:
Mark A. Terrell; NORTH CAROLINA STATE UNIV AT RALEIGH DEPT OF CIVIL ENGINEERING
|
| Currently, nationwide efforts are being made to help policymakers, construction professionals and consumers become more aware of the benefits of incorporating sustainable energy principles in residential building design and construction (Miller 1996). Any success in applying these principles is the result of effective communication by design professionals to builders and homeowners in understanding cost benefit tradeoffs for using sustainable energies in homes. The Gordon and Janice Plumblee Residence, located on ... |
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| First Principles Calculations of the Adsorption of Nitromethane and 1,1- Diamino-2,2-dinitroethylene (FOX-7) Molecules on Al2O3(0001) Surface |
AUG 2004 |
54 pages |
| Authors:
Dan C. Sorescu; Jerry A. Boatz; Donald L. Thompson; AIR FORCE RESEARCH LAB EDWARDS AFB CA SPACE AND MISSILE PROPULSION DIV
|
| First-principles calculations based on density functional theory (DFT) and the generalized gradient approximation (GGA) have been used to study the adsorption of nitromethane (NM) and 1,1-diamino-2,2-dinitroethylene (FOX-7) molecules on the basal plane of an alpha-Al2O3 crystal. The calculations employ a (2x2) supercell slab model and 3D periodic boundary conditions. Based on these calculations we have determined that both NM and FOX-7 molecules can adsorb nondissociatively on the surface with the ... |
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| Positron Plasmas in the Laboratory |
15 APR 2004 |
9 pages |
| Authors:
Clifford M. Surko; CALIFORNIA UNIV SAN DIEGO LA JOLLA DEPT OF PHYSICS
|
| The focus of this project was the development of efficient methods to accumulate low-energy positrons in the laboratory and to create positron plasmas and beams in new regions of parameter space. A new high-magnetic-field, cryogenic positron storage trap was put into operation. Rapid cooling is achieved by cyclotron emission in a 5 tesla magnetic field. Radial plasma compression is achieved using a rotating, radio-frequency electric field. New plasma operating regimes ... |
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| Fluorpolymer Property Enhancement via Incorporation of Fluorinated Polyhedral Oligomeric Silsesquioxanes (FluoroPOSS) |
12 MAR 2004 |
13 pages |
| Authors:
Joseph M. Mabry; Darrell Marchant; Brent D. Viers; Patrick N. Ruth; Scott Barker; ENGINEERING RESEARCH AND CONSULTING INC(ERC INC) EDWARDS AFB CA
|
| Fluorinated Polyhedral Oligomeric Silsesquioxanes (FluoroPOSS) are the newest class of POSS compounds. These compounds have the highest molecular weights and highest densities of any POSS compounds yet produced. They also have remarkable surface properties, which have been observed in water contact angle measurements. A number of FluoroPOSS compounds have been produced from their respective trifunctional monomers. These FluoroPOSS compounds have been blended into several fluoropolymers, including fluorinated ethylene-propylene (FEP), poly(chlorotrifluoroethylene) ... |
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| Theory of Skin Depth Interaction of Lasers with Plasmas |
20 JUL 2003 |
2 pages |
| Authors:
Heinrich Hora; J. Badziak; Y. Cang; S. Jablonski; K. Jungwirth; NEW SOUTH WALES UNIV SYDNEY (AUSTRALIA)
|
| The measured anomalous low maximum energy of ions emitted by TW-ps laser pulses in contrast to ns pulses led to the skin layer interaction model. Consequences are the nonlinear (ponderomotive) force acceleration of plasma blocks against the laser and into the target for a possible alternative laser-fusion scheme. |
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| Low-Energy VLSI Circuit Architectures |
07 JUL 2003 |
20 pages |
| Authors:
Marios C. Papaefthymiou; MICHIGAN UNIV ANN ARBOR DEPT OF ELECTRICAL ENGINEERING AND COMPUTER SCIENCE
|
| This project has investigated novel circuit architectures for low- energy VLSI systems. Its primary focus has been on charge-recovering (a.k.a. adiabatic) circuits. By steering currents across devices with low voltage drops and by recycling undissipated energy, these circuits can operate more efficiently than their conventional digital counterparts. Early investigations into adiabatic circuits have yielded very complex designs that are impractical for high-speed design. This project has led to the discovery ... |
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| A New Tunable Source for the FIR-THz Spectral Region |
26 JUN 2003 |
10 pages |
| Authors:
James H. Brownell; DARTMOUTH COLL HANOVER NH DEPT OF PHYSICS AND ASTRONOMY
|
| The Grating Coupled Oscillator (GCO) has the potential to be a practical coherent source for far-infrared/terahertz (FIR/THz) research and applications. The GCO, simply an electron beam skimming a diffraction grating, has inherently many desirable features: continuously tunable from microwave to visible, continuous wave at room temperature, excellent spatial and spectral quality, stable, compact, robust, simple, and economical. Alternative sources (e.g. solid-state, short-pulse optical switches, free-electron lasers, and blackbody) do not ... |
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| Characteristics of the T-220 HT Hall Effect Thruster |
19 JUN 2003 |
17 pages |
| Authors:
J. B. McVey; E. J. Britt; S. F. Engelman; F. S. Gulczinski; E. J. Beiting; PRATT AND WHITNEY SPACE PROPULSION SAN JOSE CA
|
| In recent tests the plume current density profile, plume ion energy, and radiated EMI were characterized for Pratt & Whitney's T-220HT Hall Effect thruster. The T-220HT is a high power (6-20 kW) thruster designed for maximum peak thrust. Tests covered a power range from 8-10 kW and discharge voltages of 300 and 600 V. Plume measurements at Air Force Research Laboratory (AFRL) facilities demonstrated plume widths narrower than typical Hall ... |
|
| Optical Calibration of TLD Readers |
30 APR 2003 |
76 pages |
| Authors:
Jeffrey H. Dormo; NAVAL ACADEMY ANNAPOLIS MD
|
| The Navy uses thermoluminescent dosimeters (TLDs) on all of its nuclear warships. TLDs measure the amount of radiation a person receives through the use of a small internal crystal. Electrons in the crystal are excited to a higher energy state when they absorb radiation. If the crystal is later taken out of the TLD and heated to a high temperature, the electrons drop back to the lower energy state, emitting ... |
|
| Characterization and Improvement of Polymer Solution Light-Emitting Devices |
03 MAR 2003 |
19 pages |
| Authors:
Yang Yang; Fred Wudl; CALIFORNIA UNIV LOS ANGELES DEPT OF MATERIALS SCIENCE AND ENGINEERING
|
| Our original objective was the understanding of polymer solution light-emitting devices (SLED), from device mechanism to materials. After a two- year intense research on SLEDs, we have expanded our project to other areas, from SLEDs, to phosphorescent PLEDs, and high performance photovoltaic devices. It is realized that our SLED has a similar mechanism as the ECL process. The electrogenerated chemiluminescence (ECL) process usually involves at least two species (or two ... |
|
| Local Crystal Field Analysis of Eu(3+) and Er(3+) Ions in a Wide Band Gap Semi-Conductor GaN |
MAR 2003 |
37 pages |
| Authors:
Fabienne Pelle; CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE BELLEVUE (FRANCE)
|
| From time resolved and site-selective excitation spectroscopy, three sites have been identified for Er(3+) ions in GaN. The main center was ascribed to Er(3+) ions substituted on the Ga sub-lattice, the two others assigned to Er(3+) complexes in interstitial positions. The complex decay profile of the (4) S(3/2) fluorescence of the main center and its concentration dependence indicate the occurrence of energy transfers between adjacent Er(3+) ions. The fluorescent transients ... |
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| Spatial Intensity Gradients of Impulsive Particle Events and Supradiffusive Magnetic Fields |
2003 |
5 pages |
| Authors:
B. R. Ragot; S. W. Kahler; TEXAS UNIV AT AUSTIN DEPT OF ASTRONOMY
|
| The low-energy ion intensity profiles of impulsive solar energetic particle (SEP) events display both sharp (< 2.5 min) local gradients and larger scale ( 1-6 hour) dropouts, indicative of fast crossfield transport on the larger scales in spite of restricted short-scale transport. Rapid variations and modulations within the few-hour long channels of enhanced intensity are also observed. We show that these features are a signature of strong supradiffusion of magnetic ... |
|
| Diet and Physical Performance |
2003 |
14 pages |
| Authors:
Scott J. Montain; Andrew J. Young; ARMY RESEARCH INST OF ENVIRONMENTAL MEDICINE NATICK MA MILITARY NUTRITION DIV
|
| This paper provides a historical summary of military nutrition research into the role of diet for sustaining soldier physical performance. Studies of underfeeding document that physical performance is preserved during several days of underfeeding provided that sufficient carbohydrate and minerals are consumed to minimize the diuresis associated with semi-starvation diets, and that serial intake of carbohydrate is available to support metabolism during prolonged work. The Military Recommended Dietary Allowances, AR ... |
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| Low Energy Electronics Design for Mobile Platforms |
03 DEC 2002 |
19 pages |
| Authors:
J. East; A. Hero; L. Katehi; S. Lafortune; P. Mazumder; MICHIGAN UNIV ANN ARBOR DEPT OF ELECTRICAL ENGINEERING AND COMPUTER SCIENCE
|
| In order to address the need for low-energy electronics design for mobile platforms in future Army communication systems a multidisciplinary effort is needed to investigate system and component design, simulation and optimization techniques. The emphasis in this research project is on the optimization, from a systems perspective, of energy requirements for a given performance level incorporating realistic models of device and circuit characteristics and energy consumption. The objectives of our ... |
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| Bonded Fly Ash: A Low-Energy Replacement for Portland Cement Concrete to Improve Resistance to Chem-Bio Intrusion |
OCT 2002 |
13 pages |
| Authors:
Mark Anderson; Dov Dover; APPLIED RESEARCH ASSOCIATES INC PANAMA CITY FL
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| The paper discusses the background of cementitious materials, and generally compares natural (Pozzolanic) cement to manufactured (Portland) cement. Fly ash is discussed as a common Pozzolan, and in particular, the low- energy requirement for fly ash as compared to Portland cement. Also, photomicrographs of fly ash particles and of chemically bonded fly ash are compared to a photomicrograph of Portland cement particles and a photograph of Portland cement concrete to ... |
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| Photoluminescence Studies of Two-Dimensional Electron Gas in Modulation Doped A1xGa1-xN/GaN Structures Grown on SI 4H-SiC by MOCVD |
JUL 2002 |
11 pages |
| Authors:
Fred Semendy; Patrick Folkes; Alfred H. Huang; Michael Wraback; ARMY RESEARCH LAB ADELPHI MD
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| Electron devices with ever-increasing operating speed are used for applications such microwave switches or amplifiers. As the physical dimensions of these devices (e.g., field effect transistors) become smaller, thinner channel layers and higher electron concentrations are required to provide high performance operation. This is because current for faster discharge of capacitance in these microwave device structures is proportional to the carrier velocity as well as the carrier density. This requirement ... |
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| Development of an RF Ion Guide for Trapping Energetic Radioactive Nuclear Ions |
24 JUN 2002 |
9 pages |
| Authors:
M. Wada; Y. Ishida; T. Nakamura; N. Oshima; Y. Nakai; SOPHIA UNIV TOKYO (JAPAN) DEPT OF PHYSICS
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| Although the projectile fragment separator (RIPS) at the RIKEN accelerator facility (RARF) provides wide variety of energetic radioactive beams, it is not adequate for low energy beam experiments such as precision spectroscopy of trapped ions. Aiming for an efficient deceleration and cooling of energetic radioactive ions, the development of an rf ion guide system which comprises a large He gas cell and an rf funnel structure in the cell is ... |
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| Initiation of Chemical Reactions in Energetic Materials Using Plasmas and Arc Channels |
29 MAR 2002 |
35 pages |
| Authors:
Mohamed A. Bourham; NORTH CAROLINA STATE UNIV AT RALEIGH DEPT OF NUCLEAR ENGINEERING
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| Experiments were conducted to determine the spatial and temporal distribution of the plasma temperature, pressure, number density, and velocity in the plasma-flow-field of an electrothermal source. The experiments revealed a decreasing plasma pressure, plasma temperature and plasma number density as plasma is leaving the capillary source and expands in air. The plasma jet velocity 2 inches from the source exit was found to be about 1300 m/s. Following plasma flow-field ... |
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| Positron Plasmas in the Laboratory |
20 MAR 2002 |
6 pages |
| Authors:
Clifford M. Surko; CALIFORNIA UNIV SAN DIEGO LA JOLLA
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| This grant supported work to develop efficient methods to accumulate low-energy positrons in the laboratory and to use the resulting positron plasmas for a range of scientific and technological applications. Techniques for trapping and manipulating positrons were refined and expanded. A new generation of positron accumulator was designed and built. It functions up to specifications, confining 3 x 10(exp 8) positrons at densities >- 10(exp 7)/cu cm. A new technique ... |
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| Test and Analysis of Composite Sandwich Panels With Impact Damage |
MAR 2002 |
67 pages |
| Authors:
R. C. Moody; Anthony J. Vizzini; MARYLAND UNIV COLLEGE PARK DEPT OF AEROSPACE ENGINEERING
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| Flat and curved (1.07-m radius) sandwich panels of various widths (83, 152, and 305 mm) were impacted and loaded uniaxially in compression until failure. Test results indicated that the width and curvature of the specimen had little effect on the ultimate strength. However, the point at which the impact damage grew as indicated by a nonlinear strain response was a function of The width and curvature of the specimen. An ... |
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Reports by Keyword(s)
LOW ENERGY
