| Operation of SCINDA Receiver at the University of Calcutta |
13-Nov-2009 |
8 pages |
| Authors:
Ashish K DasGupta; CALCUTTA UNIV (INDIA)
|
 | The SCINDA receiver has been operational at the Institute of Radio Physics and Electronics, University of Calcutta, Calcutta, India since November 2006. During the period July 2008 through July 2009, operation of the SCINDA receiver has been almost uninterrupted except during the total solar eclipse of July 22, 2009. A dedicated broadband internet connection is operational from the government-run Bharat Sanchar Nigam Limited (BSNL) since October 2008. An on‐line UPS ... |
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| Objective Estimates of Westward Rossby Wave and Eddy Propagation from Sea Surface Height Analyses |
17-Mar-2009 |
19 pages |
| Authors:
C N Barron; A B Kara; G A Jacobs; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS OCEANOGRAPHY DIV
|
| An objective method to estimate westward propagation of sea surface height (SSH) anomalies is introduced and compared to a subjective technique. Both approaches use time series extracted from global SSH analyses, prepared by optimal interpolation of altimeter data, as described in detail. The cost function used in the objective method calculates the mean along-slope standard deviation, where slope is the reciprocal of propagation speed and defines the angle of linear ... |
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| Boundary Avoidance Tracking: Consequences (and Uses) of Imposed Boundaries on Pilot-Aircraft Performance |
Mar-2009 |
115 pages |
| Authors:
Ryan D Blake; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
|
| This thesis presents the results of research into the Boundary Avoidance Tracking (BAT) theory, which states that often pilots control an aircraft not in an attempt to maintain some condition, but to avoid some real or perceived boundaries. This pilot modeling concept was studied using over 30 pilots in simulator and flight tests. The pilot-aircraft system was evaluated with 3 different lateral-directional control models. Pilots were given a roll angle ... |
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| The Distribution of Breaking and Non-Breaking Wave Impact Forces |
Mar-2009 |
40 pages |
| Authors:
Anne M Fullerton; Ann Marie Powers; Don C Walker; Susan Brewton; NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD HYDROMECHANICS DIRECTORATE
|
| The magnitude of wave impact loads varies greatly, depending upon whether the wave is breaking, as well as on the wave height, length, steepness, and the geometry and immersion of the impacted structure. This report describes an experiment that was performed to characterize the distribution of breaking and non-breaking wave impact loads over a surface, similar to those performed in 2005 with non-breaking wave impact loads and those performed in ... |
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| Characterizing the Exhaust Plume of the Three-Electrode Micro Pulsed Plasma Thrusters |
Mar-2009 |
115 pages |
| Authors:
Seo Myeongkyo; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
|
| Three-electrode micro-PPTs are a new version of two electrode micro-PPTs devices. Performance predictions and contamination expectations are essential characteristics needed by satellite designers. In order to focus on thruster specific impulse, thrust and efficiency, measuring the exhaust velocity or impulse bit and propellant consumption rate is essential. While this is not always possible to measure directly, focusing on the ejected mass from the PPT provides significant information allowing determination of ... |
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| Waypoint Generation Based on Sensor Aimpoint |
Mar-2009 |
173 pages |
| Authors:
Shannon M Farrel; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
|
| This research develops waypoint generation algorithms required to keep a point of interest (POI) in the field of view (FOV) of a fixed sensor on a micro air vehicle (MAV), in the presence of a constant wind. The waypoint generation algorithms establish waypoints such that a fixed sensor on a MAV at that waypoint and assumed attitude would be pointed directly at the POI. Two scenarios are explored: one where ... |
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| Design and Implementation of a Motor Incremental Shaft Encoder |
01-Sep-2008 |
119 pages |
| Authors:
La; Andrew M Valley; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The Department of Electrical and Computer Engineering at the Naval Postgraduate School continuously develops new design applications and searches for new ways to arm the students with the tools necessary to gain a greater understanding of advanced motor applications. One such tool is the Student Design Center (SDC). The SDC utilizes Field Programmable Gate Array (FPGA) technology for digital control of motor applications. One of the key factors in motor ... |
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| Mass Remaining During Evaporation of Sessile Drop |
01-Sep-2008 |
35 pages |
| Authors:
James E Danberg; SCIENCE APPLICATIONS INTERNATIONAL CORP (SAIC) ABINGDON MD
|
| A theory to predict the evaporation rate of HD (mustard agent) for the special case of a glass substrate has been developed. This is an important reference case for the wind tunnel and field test measurements of the HD evaporation rate. The HD drop is treated as a spherical segment with a constant base diameter characterized by the variation of the droplet shape factor (height to base diameter) or contact ... |
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| Morphing Aircraft Structures: Research in AFRL/RB |
01-Sep-2008 |
35 pages |
| Authors:
Brian Sanders; Shiv Joshi; Jayanth Kudva; Geoffrey J Frank; Franklin E Eastep; Bryan Cannon; Matthew P Snyder; Jason C Bowman; Gregory W Reich; Terrence Weisshaar; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH AIR VEHICLES DIRECTORATE
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| This report reviews research in several different areas related to morphing aircraft structures undertaken in AFRL/RBSA. The first is an aeroelastic analysis of a folding-wing vehicle to determine the flutter boundaries of the wing at different fold angles. The second is the development of a simulation tool to study both the flight stability of a morphing vehicle during the morphing process, and the kinematic stability of the morphing mechanism subject ... |
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| Video Metrology |
01-Jun-2008 |
|
| Authors:
Tony Scoleri; DEFENCE SCIENCE AND TECHNOLOGY ORGANISATION EDINBURGH (AUSTRALIA) INTELLIGENCE SURVEILLANCE AND RECONNAISSANCE DIV
|
 | This report describes a range of techniques to carry out real-world measurements from a single image of a scene. The methods have been incorporated in an interactive system where they were tested and compared. The performance of the system has been evaluated on various images for which the aim was to measure a person's height. Experiments revealed that the methods yielded accurate and consistent results, which matched the true person's ... |
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| Design, Implementation, and Characterization of a Dedicated Breast Computed MammoTomography System for Enhanced Lesion Imaging |
01-Mar-2008 |
29 pages |
| Authors:
Randolph L McKinley; DUKE UNIV DURHAM NC
|
| The overall goal of this work was to design, implement, and characterize a novel dedicated mammotomography system for enhanced lesion detection. This novel system allows fully 3-D imaging of a pendant, uncompressed breast using novel 3-D complex orbit capabilities. A prototype system has been designed, developed, and extensively characterized with a number of figures of merit including SNR, dose efficiency, and contrast sensitivity. Results indicate the potential for sub dual-view ... |
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| Blast Pendulum Testing of Milliken Tegris Panels |
JAN 2008 |
|
| Authors:
Donald J. Grosch; Erick J. Sagebiel; Hal Eleazer; SOUTHWEST RESEARCH INST SAN ANTONIO TX
|
| Milliken contracted Southwest Research Institute (SwRI) to conduct blast pendulum tests on various panels. The blast pendulum allows one to investigate a material's capability of mitigating sample deformation and bulk structural loading that result from close-in blast loading. The methodology is based upon placing a sample in a semi-rigid frame. The frame is supported by large supports that are free to rotate about a fixed position. Based upon the angular ... |
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| Numerical Modeling of the Airborne Radar Signature of Dismount Personnel in the UHF-, L-, Ku-, and Ka-Bands |
DEC 2007 |
30 pages |
| Authors:
Calvin Le; Traian Dogaru; ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE
|
| This technical report presents numeric computations of the radar cross section (RCS) of a human body placed on top of a ground plane, as seen by an airborne radar. The simulated data was collected in four frequency bands, at low microwave frequencies (UHF- and L-bands), and high microwave frequencies (Ku- and Ka-bands). For the low frequency bands we used the Finite Difference Time Domain (FDTD) modeling technique, whereas for the ... |
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| Induced Forces and Moments of a Tumblehome Hullform (Model 5613) Undergoing Forced Roll in Waves |
NOV 2007 |
25 pages |
| Authors:
Anna M. Fullerton; Thomas C. Fu; Don C. Walker; James R. Rice; NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD HYDROMECHANICS DIRECTORATE
|
| Predictions of large amplitude roll motions and capsize events have proven to be difficult and include large uncertainty. A factor that contributes to the difficulty in predictions is a lack of knowledge of resultant forces and moments for large roll angles. The equations currently used by numerical models to predict forces and moments due to roll motion are based on experimental data performed within a small range of roll amplitudes. ... |
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| Temporal Subtraction of Digital Breast Tomosynthesis Images for Improved Mass Detection |
OCT 2007 |
22 pages |
| Authors:
Christina M. Li; DUKE UNIV DURHAM NC
|
| Digital breast tomosynthesis (DBT) strives to overcome the obstacles presented in conventional 2D mammography by taking multiple projections over a fixed angle and reconstructing volumetric data isolates overlying anatomy from in-plane structures and amplify the conspicuity of lesions. Temporal subtraction automates the process of comparative analysis by using two images taken sequentially and subtracting them in order to find temporal discrepancies. The purpose of this project is to determine the ... |
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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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| Calculating Sputter Rate Angular Dependence Using Optical Profilometry (Preprint) |
26 JUL 2007 |
34 pages |
| Authors:
Alexander C. Barrie; Bryan S. Taylor; Jared M. Ekholm; Jr Hargus William A.; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| This work attempts to determine angular dependence curves for sputter rates of a material based on a single experimental measurement. An aluminum cylinder was exposed to a BHT-200 plume, and the resulting erosion profile was measured. This profile was fed into an optimizer, which calculated the angular dependence curve to match the given erosion profile. The calculated profile matched well with the experimental profile; however, neither matched well with previously ... |
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| The Impact of Manifold-to-Orifice Turning Angle on Sharp-Edge Orifice Flow Characteristics in both Cavitation and Non-Cavitation Turbulent Flow Regimes (Preprint) |
JUN 2007 |
21 pages |
| Authors:
W. H. Nurick; T. Ohanian; D. G. Talley; P. A. Strakey; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| The approach taken was to analyze the results in a manner consistent with application by design engineers to new and existing applications, while providing some insight into the processes that are occurring. This paper deals with predicting the initiation of cavitation, cavitation impacts on Cc, and non-cavitation impacts on Cd from L/D of 5 sharp-edge orifices with both single angle and compound angle directional flow. The results show that in ... |
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| Self Assembled, Ultra-Hydrophobic Micro/Nano-Textured Surfaces |
APR 2007 |
26 pages |
| Authors:
Adam M. Rawlett; Joshua A. Orlicki; Nicole Zander; Afia Karikari; Tim Long; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
|
| The formation of hierarchically ordered arrays of spherical cavities on polymer films is of interest due to potential applications in the reparation of photonic bandgaps materials, environmental sensors, and patterned light-emitting diodes. While many methods are known for the preparation of these porous materials, the breath figure approach has received significant scrutiny because of the simple and robust mechanism of pattern formation. Breath figures are patterned arrays of micrometer-sized defects ... |
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| Anisotropy in the South Atlantic Anomaly |
JAN 2007 |
97 pages |
| Authors:
Shaun M. Easley; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT/DEPT OF ENGINEERING PHYSICS
|
| From June 2000 through July 2006, the TSX-5 satellite measured proton fluxes in the Earth?s magnetosphere using its CEASE instrument. A review of the satellite data by scientists at AFRL/VSBX revealed an unanticipated, recurring bi-modal structure in histograms of the proton counts. This research identified the bi-modal behavior as anisotropic in nature, and the result of two separate processes. At low altitudes the anisotropy was well described by the classic ... |
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| Advanced ESM Angle Tracker. Volume 1. Theoretical Foundations |
29 DEC 2006 |
42 pages |
| Authors:
Edward N. Khoury; NAVAL RESEARCH LAB WASHINGTON DC
|
| This report summarizes the NRL implementation of a filter used for ESM angle tracking. The filter is an Interactive Multiple Model (IMM) filter that uses three standard Kalman filters as a basis for filtering and predicting emitter bearing angle. Filter selection for the IMM is based on the expected variation of emitter trajectories and the imposed spherical coordinate system. The derivation of the IMM is well documented and is not ... |
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| Evolution of Time Scales |
DEC 2006 |
7 pages |
| Authors:
Dennis D. McCarthy; NAVAL OBSERVATORY WASHINGTON DC
|
| Time scales have continued to evolve to meet the developing needs of users in modern times. Fifty years ago time based on astronomical observations of the Earth's rotation was sufficient to meet the needs for time, both civil and technical. During that 50-year interval, however, not only have these scales been expanded, but the advent of practical atomic clocks has led to the development of time scales based on atomic ... |
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| Progress Report of the IAU Working Group on Precession and the Ecliptic |
DEC 2006 |
6 pages |
| Authors:
J. L. Hilton; N. Capitaine; J. Chapront; J. M. Ferrandiz; A. Fienga; T. Fukushima; J. Getino; P. Mathews; J-L. Simon; M. Soffel; NAVAL OBSERVATORY WASHINGTON DC
|
| The IAU Working group on Precession and the Ecliptic looked at several solutions for replacing the precession part of the IAU 2000A precession-nutation model, which is not dynamically consistent. These comparisons show that the Capitaine et al. (2003) precession theory, P03, is both dynamically consistent and the solution most compatible with the IAU 2000A nutation model. The two greatest sources of uncertainty in the precession theory are the rate of ... |
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| Experimental Investigation of Pitch Control Enhancement to the Flapping Wing Micro Air Vehicle |
DEC 2006 |
135 pages |
| Authors:
Chin C. Kian; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The mechanical pitching characteristic of the NPS flapping-wing Micro Air Vehicle (MAV) developed by Professor Kevin D. Jones are studied experimentally through the use of constant temperature anemometry and force balance techniques. The MAV without the main fixed-wing is placed in a laminar flow field within a low speed wind tunnel with the wake after the flapping wings characterized with a constant temperature anemometer and thrust generation measured by a ... |
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| The Induced Forces and Motions of a Tumblehome Hullform (Model 5613) Undergoing Forced Roll |
DEC 2006 |
30 pages |
| Authors:
Anne M. Fullerton; Thomas C. Fu; Don C. Walker; James R. Rice; Young S. Hong; NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD
|
| Predictions of large amplitude roll motions and capsize events have proven to be difficult and include large uncertainty. One of the reasons for this is a lack of knowledge of resultant forces and moments for large roll angles. Currently, the equations used by numerical models to predict forces and moments due to roll motion are based on experimental data performed within a small range of roll amplitudes. A data set ... |
|
| Ballistic Missile Trajectory Estimation |
DEC 2006 |
77 pages |
| Authors:
Joseph Dituri; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Angles measurements from optical systems are the primary source of data for maintaining the orbits of high altitude satellites. Radar measurements are used primarily for low Earth orbit (LEO) satellites. Recently it has been shown that the accuracy of the orbit updates using only optical system angles-only data is just as good, if not better, than the performance from radar systems for LEO satellites. The purpose of this thesis is ... |
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| Ultraviolet Properties of Halo Coronal Mass Ejections: Doppler Shifts, Angles, Shocks, and Bulk Morphology |
20 NOV 2006 |
20 pages |
| Authors:
A. Ciaravella; J. C. Raymond; S. W. Kahler; AIR FORCE RESEARCH LAB HANSCOM AFB MA SPACE VEHICLES DIRECTORATE
|
| We present UV spectral information for 22 halo or partial halo CMEs observed by UVCs. The CME fronts show broad line profiles, while the line intensities are comparable to the background corona. The Doppler shifts of the front material are generally small, showing that the motion of gas in the fronts is mostly transverse to the line of sight. This indicates that, at least in halo CMEs, the fronts generally ... |
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| Effects of Phase Difference Between Axial and Contact loads on Fretting Fatigue Behavior of Titanium Alloy. |
SEP 2006 |
164 pages |
| Authors:
Mohammad Almajali; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
|
| movement. It results in a reduction of the material life as compared to the plain fatigue. Most of the previous works were accomplished under a constant applied normal load and a little effort was done under a variable contact load, while none of these studies have considered the phase difference between the axial and the contact load. The primary goal of this study is to investigate the effect of phase ... |
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| Another Analytical Approach to Predicting Munition Trajectories |
SEP 2006 |
26 pages |
| Authors:
Gene R. Cooper; Paul Weinacht; James F. Newill; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
|
| Analysis presented here addresses a previous problem concerning free-flight projectiles governed by the two-dimensional, point mass equations representing drag as a power law. Down-range distance is taken to be the independent variable which yields a third-order differential equation governing the projectile's flight. An approximate solution is obtained which is shown to be very accurate for gun elevation angles up to 30 degrees. Previously examined engineering characteristics for flat fire are ... |
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| Seafloor Ripples Created by Waves from Hurricane Ivan on the West Florida Shelf |
SEP 2006 |
|
| Authors:
Colleen M. Bowers; MASSACHUSETTS INST OF TECH CAMBRIDGE
|
| Recent studies have shown that the presence of sand ripples on the seabed improves sonar detection of buried mines at sub-critical angles. Sidescan sonar data of ripples off on the west Florida shelf were collected as part of ONR's Ripples Departmental Research Initiative (DRI) September 26-29th and November 7-9th, 2004. Hurricane Ivan, the strongest storm of the 2004 hurricane season, passed over the experiment site a week before the first ... |
|
| The Loss Cone Imager (LCI) |
24 JUL 2006 |
143 pages |
| Authors:
E. S. Beiser; T. A. Fritz; BOSTON UNIV MA CENTER FOR SPACE PHYSICS
|
| The Loss Cone Imager (LCI) will serve as an integral component for an Air Force Research Laboratory (AFRL) experiment called WPIx. The WPIx experiment will be flown on the Demonstration and Science Experiment (DSX) spacecraft, to be launched in 2009, with a nominal one-year mission. The LCI will measure the local population of energetic particles, concentrating on determining their intensity within the magnetospheric loss cone. The LCI will be able ... |
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| Radar Cross-Section (RCS) Measurements of a Dismount With Rocket-Propelled Grenade (RPG) Launcher at Ka-Band |
JUL 2006 |
56 pages |
| Authors:
Suzanne R. Stratton; Robert L. Bender; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| The U.S. Army Research Laboratory's (ARL's) Radio Frequency and Electronics Division sponsored and conducted a series of measurements to characterize the millimeter wave (MMW) signatures of one Soldier carrying a rocket-propelled grenade (RPG) launcher with grenade at 34 GHz over three depression angles and for three different body postures: prone, kneeling, and standing. The measurements were taken by ARL at its outdoor signature research facility at Aberdeen Proving Ground, MD, ... |
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| Mitigation of Ionospheric Effects on High Frequency Surface Wave Radar |
01 JUN 2006 |
|
| Authors:
Ryan J. Riddolls; DEFENCE RESEARCH AND DEVELOPMENT CANADA OTTAWA (ONTARIO)
|
| High Frequency Surface Wave Radar (HFSWR) takes advantage of the di raction of electromagnetic waves over the conducting ocean surface to detect, locate, and track surface vessels beyond the line-of- sight horizon of the earth. However, long-range surface vessel detection is often confounded by radar clutter comprising echoes from the ionospheric plasma. In this paper, we characterize the angular spectrum of these re ections, and from this information deduce the ... |
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| An Analysis of Nonlinear Elastic Deformations for a Homogeneous Beam at Varying Tip Loads and Pitch Angles |
JUN 2006 |
106 pages |
| Authors:
Robert J. McGraw; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH DEPT OF AERONAUTICS AND ASTRONAUTICS
|
| The Princeton beam experiments of 1975 were performed in hopes of producing viable data for beam nonlinear elastic deformation models in hopes of improving helicopter main beam designs. The recorded data, specifically for homogeneous beams of 7075 aluminum, have been referenced as a baseline for the past thirty years to validate numerous computer models and theories in an effort to build beams capable of withstanding aeroelastic, static, and dynamic loading. ... |
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| Dynamic Nonlinear Bending and Torsion of a Cantilever Beam |
JUN 2006 |
62 pages |
| Authors:
Michael S. Whiting; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH
|
| This effort sought to measure the dynamic nonlinear bending and torsion response of a cantilever beam. The natural frequencies of a cantilever beam in both chord and flap directions were measured at different static root pitch angles with varying levels of weights attached at the free end. The results were compared with previous experimentation to validate the data and testing procedures while lowering the associated error bands. Additionally, methodology for ... |
|
| Validation of a Scaled Plane Strain Hypervelocity Gouging Model |
MAR 2006 |
99 pages |
| Authors:
Ronald J. Pendleton; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
|
| The phenomenon of high speed impact is of great interest to the Air Force of Scientific Research and the Air Force Research Laboratory's Holloman High Speed test track. Roccket sled testss at the ffacility frequently arre limited to velocities lower than actually attainaable due to damage to the rail in hte form of gouges. Direct observation of the gouging pehenomenon is not currently possible. This leaves computational modeling as the ... |
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| Fretting Fatigue Behavior of Nickel Alloy IN-100 |
MAR 2006 |
135 pages |
| Authors:
Elhoucine Madhi; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH DEPT OF AERONAUTICS AND ASTRONAUTICS
|
| In this study, a systematic investigation of the fretting fatigue behavior of nickel alloy, IN-100 was carried out. The study includes both experimental work and the corresponding analysis of the contact conditions, and the latter is accomplished using the finite element method. Fretting fatigue tests were performed over a wide range of axial stresses to examine both low and high cycle fretting fatigue under constant contact load and the influence ... |
|
| Self-Pumped Photorefractive Gratings in Fe:KNbO3 (Preprint) |
JAN 2006 |
16 pages |
| Authors:
Dean R. Evans; G. Gook; J. L. Carns; M. A. Saleh; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH SURVIVABILITY AND SENSOR MATERIALS DIV/HARDENED MATERIALS
|
| *High gain confirmed in off-axis geometries for Fe:KNbO3; *Mismatch between theory and experiment for mid-range crystal angles, especially for the a-c plane; *Large apparent variation in the effective trap density with crystal angle; *Modified theory gives a good fit to experimental data; *Mechanism for trap density anisotropy is unclear. |
|
| Optimal GEO Lasercomm Terminal Field of View for LEO Link Support |
2006 |
11 pages |
| Authors:
Charles W. Hindman; Jeffrey P. Hunt; Brian S. Engberg; Kevin J. Walchko; AIR FORCE RESEARCH LAB KIRTLAND AFB NM SPACE VEHICLES DIRECTORATE
|
| As alternatives to the traditional gimbaled terminal design, future satellite based laser communications terminals are envisioned that utilize a wide field or view or field or regard (WFOV/WFOR) . This approach can be advantageous in situations requiring rapid switching between user terminals, support for multiple terminals simultaneously (via TDMA, SDMA or WDMA) or other non-standard mission requirements. However, a traditional gimbaled terminal has the capability to continuously track a single ... |
|
| Development of Textured Buffer Layer on Metal Tapes for Oxide Superconductors |
14 OCT 2005 |
22 pages |
| Authors:
R. S. Bhattacharya; Y. Xu; UES INC DAYTON OH
|
| Report documents the development effort dedicated to the scale up of inclined substrate deposition (ISD) of textured magnesium oxide (MgO) on continuous tapes of nickel based alloys under an AFOSR Phase II STTR program, in partnership with Argonne National Laboratory (ANL). Long length highly textured MgO template has been successfully deposited on HC substrate in the reel-to-reel system. High deposition rate up to 10 nm/sec of the ISD MgO ebeam ... |
|
| Liquid Crystal on Silicon Non-Mechanical Steering of a Laser Vibrometer System |
SEP 2005 |
84 pages |
| Authors:
Kevin S. Kuciapinski; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
|
| This research examined the possibility of using a non-mechanical beam steering device to steer the beam of a coherent laser radar system. Non-mechanical beam steering devices offer many advantages in size, weight, power requirements, and steering speeds. Additionally, non-mechanical beam steering devices present the capabilities of splitting a single beam into multiple beams as well as beam forming and expanding. The coherent laser radar system used was a Laser Vibrometer ... |
|
| Bone Conduction Head Sensitivity Mapping: Bone Vibrator |
24 AUG 2005 |
45 pages |
| Authors:
Maranda McBride; Tomasz R. Letowski; Phuong K. Tran; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| The military is interested in ways to incorporate radio communication in a multi-tasking environment. Bone conduction (BC) radio communication is an attractive means to communicate because it offers the ability to transmit and receive radio communication without compromising auditory awareness of the environment. Several companies are attempting to accommodate the needs of the military by creating communication devices that incorporate BC technologies. However, the effectiveness of these devices differs in ... |
|
| Self-Assembled, Ultra-Hydrophobic Micro/Nano-Textured Surfaces |
AUG 2005 |
18 pages |
| Authors:
Adam M. Rawlett; Joshua A. Orlicki; Afia Karikari; Tim Long; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| Hierarchical self assembly of nano-scale components (i.e., abalone shells, etc.) has been perfected by nature, yet the ability for scientists to utilize similar techniques is still in its infancy. The assembly of complex nano- and micro-components via self organizing means, rather than serial or parallel processing methods (e.g., electron beam lithography or nano-imprinting, respectively), could exploit the inherent benefit of these entities in a more elegant, economic means. The self ... |
|
| Effects of Sample Impurities on the Analysis of MS2 Bacteriophage by Small-Angle Neutron Scattering |
AUG 2005 |
21 pages |
| Authors:
Ilya Elashvili; Charles H. Wick; Deborah A. Kuzmanovic; Susan Krueger; Catherine O'Connell; EDGEWOOD CHEMICAL BIOLOGICAL CENTER ABERDEEN PROVING GROUND MD RESEARCH AND TECHNOLOGY DIR
|
| Small angle neutron scattering (SANS) has been used to extend the structural characterization of the MS2 phage by examining its physical characteristics in solution. The impact of small molecular weight impurities of the resolution of structural data obtained by SANS of the bacteriophage MS2 distorts the resolution and sharpness of contrast variation peaks. However, the position of the visible peaks is unchanged contaminated samples when compared to pure MS2 samples. ... |
|
| Multidimensional Quasi-Linear Diffusion of Radiation Belt Electrons |
28 JUL 2005 |
5 pages |
| Authors:
J. M. Albert; S. L. Young; AIR FORCE RESEARCH LAB HANSCOM AFB MA SPACE WEATHER CENTER OF EXCELLENCE
|
| We consider diffusion of outer zone radiation belt electrons by chorus waves. Quasi-linear diffusion coefficients valid outside the plasmasphere have only been calculated recently, and indicate that the energy and cross diffusion rates can be comparable to that for pitch angle diffusion. Proper solution of the diffusion equation for phase space density must therefore be based on the full diffusion tensor, but this has been plagued by numerical problems associated ... |
|
| A New Classification Method Based on Cloude-Pottier Eigenvalue/Eigenvector Decomposition |
25 JUL 2005 |
5 pages |
| Authors:
Cao Fang; Hong Wen; CHINESE ACADEMY OF SCIENCES BEIJING (CHINA) NATIONAL KEY LAB OF MICROWAVE IMAGING TECHNOLOGY
|
| In this paper, a new polarimetric scattering parameter, the averaged intensity (I), is introduced to present the backscatter intensity of fully polarimetric Synthetic Aperture Radar (SAR) data. According to the particular analysis on the properties of I, a angle, and entropy H, the mapping rule of I-a-H feature space onto the Intensity-Hue-Saturation (I-H-S) color space is proposed. The authors use the IHS transform instead of a segmentation algorithm to finish ... |
|
| Characterization of a Rotary Flat Tail as a Spoiler and Parametric Analysis of Improving Directional Stability in a Portable UAV |
MAY 2005 |
125 pages |
| Authors:
Troy A. Leveron; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
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| The United States Air Force Research Lab, Munitions Directorate, Flight Vehicles, Integration Branch (AFRL/MNAV), has developed a flexible wing micro air vehicle (MAV) to be used with special tactics groups. In keeping with the requirement that this MAV be compact, previous research developed a rotatable tail mechanism which resulted in tail movement similar to that of a bird's tail. In this study the design of this tail was modified to ... |
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| Investigation of Burst Pressures Prediction of Slit Aluminum Cylinders Subjected to Localized Heating |
MAY 2005 |
36 pages |
| Authors:
C. T. Sun; T. Tanner; A. Deitemeyer; D. Nakaima; N. Bruno; D. Doering; C. Tham; R. Ulibarri; J. K. Chen; BALL AEROSPACE AND TECHNOLOGIES CORP ALBUQUERQUE NM
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| Crack Tip Opening Angle (CTOA) measurements of aluminum allow 2014-T6 (Al-2014-T6) at various temperatures and the construction of the corresponding CTOA curves were performed. The CTOA curve as the crack growth criterion was used to simulate the burst pressures in Al-2014-T6 thin-walled cylinders with a longitudinal crack of different sized under thermal and mechanical load. The crack growth is simulated using nodal release method in the ABAQUS finite element environment ... |
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| Unsteady Simulation of a Transport Aircraft Propeller Using MEGAFLOW |
25 APR 2005 |
15 pages |
| Authors:
Arne Stuermer; Mark Rakowitz; DLR INST OF AERODYNAMICS AND FLOW TECHNOLOGY BRAUNSCHWEIG (GERMANY)
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| A series of unsteady CFD simulations have been conducted for an isolated propeller configuration at lowspeed flight conditions using both a structured and an unstructured CFD method. The propeller geometry investigated is representative of a modern eight-bladed design for high-speed turboprop transport aircraft. Two typical low-speed conditions, one at zero and one at ten degrees angle of attack, were investigated and results of the two CFD methods compared with experimental ... |
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| Exploitation of Elevation Angle Control for a 2-D HF Skywave Radar |
14 APR 2005 |
6 pages |
| Authors:
S. Saillant; G. Auffray; P. Dorey; OFFICE NATIONAL D'ETUDES ET DE RECHERCHES AEROSPATIALES TOULOUSE (FRANCE)
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| ONERA, sponsored by the French Ministry of defense (Aeronautics program department SPAe), has conducted the realization and experimentations of the skywave HF radar, called NOSTRADAMUS. This is a new concept of Over-the-Horizon radar constituted of a monostatic surface array on a three arms star. This choice of structure allows an azimuthal coverage of 360 degrees and elevation beam-forming capability. This paper presents the NOSTRADAMUS system and describes the real time ... |
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