| Optimal Time and Energy Efficiency in Legged Robotics |
17-Aug-2009 |
5 pages |
| Authors:
Paul Muench; Ka C Cheok; Gregory Czerniak; ARMY RESEARCH DEVELOPMENT AND ENGINEERING COMMAND WARREN MI
|
 | Although bio-inspired legged robots have advantageous mobility, they can be very inefficient. Their intrinsic walking mobility is sometimes outweighed by the inefficiency of their drive-train. Some of these inefficiencies are due to collision losses, but they are also due to sub-optimal powering schemes. This paper addresses the powering schemes and seeks to clearly delineate an optimal solution to powering the walking motion of a two-legged or biped walker. We examine ... |
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| Thrust Augmentation in Solid Rocket Motors Using Beamed Microwave Energy |
13-Jul-2009 |
13 pages |
| Authors:
Andrew Ketsdever; Natalia E Gimelshein; Sergey F Gimelshein; ENGINEERING RESEARCH AND CONSULTING INC (ERC INC) EDWARDS AFB CA
|
| Feasibility of using beamed microwave energy to increase thrust of solid rocket motors during launch is analyzed. Coupling of microwave radiation with internal energies of micron-sized alumina particles and the successive transfer of internal energy of particles to thermal and then kinetic energy of gas is expected to be the main mechanism of thrust increase. A two-phase two-way coupled capability has been developed. For the gas phase, the capability applies ... |
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| Preliminary VHF Radar and High-Data-Rate Optical Turbulence Profile Observations Using a Balloon-Ring Platform: Post Print |
01-Jun-2009 |
36 pages |
| Authors:
Frank D Eaton; Gregory D Nastrom; Demos T Kyrazis; Don G Black; Wiley T Black; R A Black; NASTROM CONSULTING LLC SAINT CLOUD MN
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| A recent measurement campaign at Vandenberg Air Force Base involved taking simultaneous observations with a VHF radar and high-data-rate (1-micron diameter) platinum wires to sense optical turbulence (from temperature fluctuations). The radar observations produce profiles of the refractive index structure parameter, the turbulent kinetic energy, the eddy dissipation rate, the inner scale, the outer scale of turbulence, and wind speed and direction to an altitude of 20 km AGL. The ... |
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| Chemical Reactivity as a Probe of Ionic-Liquid Surfaces |
30-Apr-2009 |
18 pages |
| Authors:
Kenneth McKendrick; Carla Waring; Paul A Bagot; Matthew L Costen; HERIOT-WATT UNIV EDINBURGH (UNITED KINGDOM)
|
| This report results from a contract tasking Heriot-Watt University as follows: The work will be similar to that which the group has pioneered in related studies of the reactions of O(3P) atoms with hydrocarbon liquids. It is based on laser-photolysis of a low pressure of a suitable O(3P) precursor (NO2 at 355 nm) above the surface of the liquid. This produces O(3P) atoms with a relatively broad, superthermal kinetic energy ... |
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| Experimental/Computational Approach to Accommodation Coefficients and its Application to Noble Gases on Aluminum Surface (Preprint) |
03-Feb-2009 |
26 pages |
| Authors:
Andrew Ketsdever; Sergey F Gimelshein; Nathaniel Selden; Natalie E Gimelshein; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| A technique is proposed to assess gas-surface accommodation coefficients. The technique utilizes the fact that radiometric forces exerted on heated objects immersed in rarefied gases are governed by the interaction of gas molecules with the surface. In the present implementation, it connects measurements of radiometric forces on a heated vane in the transitional flow regime with the kinetic modeling of the flow, and derives the accommodation coefficients through the successive ... |
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| Joint Observational Research on Nocturnal Atmospheric Dispersion of Aerosols (JORNADA) |
Feb-2009 |
14 pages |
| Authors:
David Miller; Carmen Nappo; April Hiscox; CONNECTICUT UNIV STORRS
|
| Four major analyses were conducted using the stable boundary layer JORNADA data. First was the analysis of the movement of instantaneous plumes released from a spray aircraft and continuously scanned with the lidar. Techniques for quantifying the concentrations of aerosols in the drifting plumes were established. The effects on plume dynamics and spread of short time (seconds) sub-mesoscale events were quantified. The second was an analysis of wave modified flux ... |
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| Analysis of Terminal Metallic Armor Plate Free-Surface Bulging |
Oct-2008 |
18 pages |
| Authors:
Rapacki; E J Jr; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| An analysis of the bulge formed on the free-surface of the terminal metallic plate of an armor array is shown to lead to reasonable estimates of the armor array's remaining penetration/perforation resistance. Terminal ballistic performance evaluations of penetrators and armors are often performed via statistical analyses to obtain a velocity or obliquity at which the expected probability of perforation is 0.5, or an analytical form relating the residual velocity of ... |
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| Sea-Based Ballistic Missile Defense - Background and Issues for Congress |
01-Jul-2008 |
|
| Authors:
Ronald O'Rourke; LIBRARY OF CONGRESS WASHINGTON DC CONGRESSIONAL RESEARCH SERVICE
|
 | As part of its effort to develop a global ballistic missile defense (BMD) system, the Department of Defense (DOD) is modifying 18 Navy cruisers and destroyers for BMD operations, and has deployed a large BMD radar the Sea-Based X-Band Radar (SBX) on a modified floating oil platform. The eventual role of sea-based systems in the worldwide U.S. BMD architecture has not been determined. The overall issue for Congress discussed in ... |
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| Observations of Turbulent Fluxes and Turbulence Dynamics in the Ocean Surface Boundary Layer |
01-Jun-2008 |
117 pages |
| Authors:
Gregory P Gerbi; MASSACHUSETTS INST OF TECH CAMBRIDGE JOINT PROGRAM IN APPLIED OCEAN SCIENCE AND ENGINEERING
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| This study presents observations of turbulence dynamics made during the low winds portion of the Coupled Boundary Layers and Air-Sea Transfer experiment (CBLAST-low) in the ocean surface boundary layer. Observations include turbulent fluxes, turbulent kinetic energy, and the length scales of flux-carrying and energy-containing eddies. The observations of turbulent fluxes allowed the closing of heat and momentum budgets across the air-sea interface. The flux-carrying eddies are similar in size to ... |
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| Foreign Object Damage by Steel Ball Projectiles in a SiC/SiC Ceramic Matrix Composite at Ambient and Elevated Temperatures |
29 APR 2008 |
40 pages |
| Authors:
Sung R. Choi; Donald J. Alexander; NAVAL AIR WARFARE CENTER AIRCRAFT DIV PATUXENT RIVER MD
|
| Foreign object damage (FOD) phenomenon of a gas-turbine grade SiC/SiC ceramic matrix composite was determined at 25 deg C and 1316 deg C using impact velocities ranging from 115 to 440 m/sec by 1.59-mm diameter steel ball projectiles. Two types of target-specimen support were employed at each temperature: fully supported and partially supported. For a given temperature, the degree of post-impact strength degradation increased with increasing impact velocity, and was ... |
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| Turbulent Mixing in Stably Stratified Flows |
01-Mar-2008 |
101 pages |
| Authors:
MASSACHUSETTS UNIV AMHERST
|
| High resolution direct numerical simulations are used to investigate the dynamics of turbulence in flows subject to strong stable stratification, which are common in natural settings. Results are presented for two categories of simulations, uniform and non-uniform density stratification. For all simulated flows, the density stratification was held constant in time, and there was no ambient shear. Flows with uniform density stratification are first analyzed to help provide clear insight ... |
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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
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| 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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| Satellite Vulnerabilities |
18-Feb-2008 |
18 pages |
| Authors:
J W Rooker; MARINE CORPS COMMAND AND STAFF COLL QUANTICO VA
|
| From the Gulf War to Operation Iraqi Freedom, use of satellite communications increased more than 300%, and the data rate to support such operations went up by 500%. More and more, the U.S. Marine Corps is becoming dependent on satellite communications. Perhaps the U.S. military has become too dependent on satellite communications, which are subject to weather, and increasingly vulnerable to attack. Satellites are vulnerable to varieties of attack or ... |
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| Vorticity and Turbulence in the Wake of a Bridge Pier |
JAN 2008 |
29 pages |
| Authors:
R. C. Lien; Thomas B. Sanford; WASHINGTON UNIV SEATTLE APPLIED PHYSICS LAB
|
| Dissipation rates of turbulence kinetic energy and enstrophy are reported in a high Reynolds number turbulent wake. Our results represent a set of rare field observations of vorticity and turbulence in a turbulent wake with a high Reynolds number, The turbulent wake was formed by an unsteady strong tidal current interacting with a bridge pier. Measurements were taken in the intermediate wake. Both energy and enstrophy show a similar downstream ... |
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| Quasistatic and Dynamic Growth of Microscale Spherical Voids (Preprint) |
Jan-2008 |
42 pages |
| Authors:
T C Tszeng; BERKELEY MATERIALS RESEARCH PIEDMONT CA
|
| This study examines the quasistatic and dynamic growth of microscale spherical voids. A general dynamic model of void growth is first developed by considering conservation of local energy, including external work, surface energy, kinetic energy, elastic strain energy, and plastic dissipation associated with growing void driven by hydrostatic tensile stress. It properly accounts for material compressibility and limited size of elastic deformation in dynamic growth of spherical voids. A closed ... |
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| Second Moment Closure Modeling of Complex Turbulent Flows |
31 DEC 2007 |
47 pages |
| Authors:
Sharath S. Girimaji; TEXAS A AND M UNIV COLLEGE STATION DEPT OF AEROSPACE ENGINEERING
|
| Turbulence subject to unsteady forcing can exhibit novel features that cannot be explained using the well-known steady-turbulence paradigm. Modeling and prediction of such statistically unsteady flows are important in many practical AFOSR applications: turbine flows, wake-flows with vortex shedding, etc. Further, many flow control strategies depend upon the knowledge of unsteady turbulence dynamics to achieve the desired objectives. However, our understanding of unsteadily-forced turbulence dynamics or our ability to predict ... |
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| Measurements of Storm and Nonstorm Circulation in the Northern Adriatic: October 2002 Through April 2003 |
16 NOV 2007 |
21 pages |
| Authors:
Jeffrey W. Book; Richard P. Signell; Henry Perkins; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS OCEANOGRAPHY DIV
|
| Fifteen bottom-mounted Acoustic Doppler Current Profilers were deployed from October 2002 through April 2003 in the northern Adriatic Sea. Average transport from the portion of the Western Adriatic Current (WAC) along the Italian slope was 0.1470 +/- 0.0043 Sv, punctuated by bursts of more than twice that amount during storm events. Monthly means were calculated with times f strong wind-driven circulation excluded. These suggest a 2002/2003 seasonal separation consisting of ... |
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| Physical Foundations of Plasma Microwave Sources Based on Anomalous Doppler Effect |
17-Sep-2007 |
19 pages |
| Authors:
Eduard V Rostomyan; NATIONAL ACADEMY OF SCIENCE ASHTARACK (ARMENIA) INST OF RADIOPHYSICS AND ELECTRONICS
|
| This project is concerned microwave relativistic plasma electronics, dealing with problems of converting the energy of intense electron beams into high power coherent electromagnetic radiation. This is one of the main topics of AFOSR's interests on basic research in physics and electronics. Plasma filling of microwave devices allows operating at higher beam currents and gradually changing frequency of output radiation. In addition plasma mitigates voltage depression and improves characteristics of ... |
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| Analytical Extraction of Plasma Properties Using a Hall Thruster Efficiency Architecture (Preprint) |
22 AUG 2007 |
15 pages |
| Authors:
Daniel L. Brown; C. W. Larson; James M. Hass; Alec D. Gallimore; AIR FORCE RESEARCH LAB EDWARDS AFB CA SPACECRAFT PROPULSION BRANCH
|
| An investigation of the conversion from anode electrical energy to jet kinetic energy in a laboratory model Hall thruster test-bed yielded an experimentally determined thrust efficiency based on the product of propellant, voltage, and current utilization. This method accounts for the effects of the ion velocity distribution function (VDF), electron recycle fraction, plume divergence, and the fractional loss of acceleration voltage within the discharge chamber. The architecture of the efficiency ... |
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| Thrust Efficiency, Energy Efficiency, and the Role of VDF in Hall Thruster Performance Analysis (Preprint) |
29 MAY 2007 |
19 pages |
| Authors:
C. W. Larson; William A. Hargus; Daniel L. Brown; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| A rocket power efficiency equation was written to explicitly account for the effect of the velocity distribution function (VDF) of the propellant jet on the conversion of anode electrical energy to jet kinetic energy. This enabled a mathematically rigorous distinction to be made between thrust efficiency and energy efficiency. In this approach anode thrust efficiency, the commonly reported figure of merit for Hall thrusters, is the product of three utilization ... |
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| Experimental and Numerical Analysis of a DECSMAR Structure's Deployment and Deployed Performance |
APR 2007 |
17 pages |
| Authors:
Eric L. Pollard; Thomas W. Murphey; Gregory E. Sanford; CSA ENGINEERING INC ALBUQUERQUE NM
|
| The objective of this research is to analyze the deployment and deployed performance of a recently developed, self-deployable truss architecture composed of carbon fiber reinforced plastic (CFRP) tape-spring elements and embedded shape memory alloy (SMA) flexures; this particular structural system is referred to as deployable elastic composite shape memory alloy reinforced (DECSMAR) and is representative of a concentrated, material deformation based deployable architecture. The scope of this study encompasses numerically ... |
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| Missile Defense: Actions Needed to Improve Information for Supporting Future Key Decisions for Boost and Ascent Phase Elements |
APR 2007 |
40 pages |
| Authors:
Janet A. St. Laurent; Paul L. Francis; Barbara H. Haynes; Gwendolyn R. Jaffe; Brenda M. Waterfield; Todd Dice; Jeffrey R. Hubbard; Nabajyoti Barkakati; Hai V. Tran; Ron La Due Lake; Susan C. Ditto; GOVERNMENT ACCOUNTABILITY OFFICE WASHINGTON DC
|
| The Department of Defense (DoD) has spent about $107 billion since the mid-1980s to develop a capability to destroy incoming ballistic missiles. DoD has set key decision points for deciding whether to further invest in capabilities to destroy missiles during the initial phases after launch. In March 2006, DoD issued a report on these capabilities in response to two mandates. To satisfy a direction from the House Appropriations Committee, GAO ... |
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| Development of a Miniaturized Hadamard Transform Time-of-Flight Mass Spectrometer |
FEB 2007 |
27 pages |
| Authors:
Richard N. Zare; STANFORD UNIV CA DEPT OF CHEMISTRY
|
| This report details advances in theory and technology for the precise deflection of high kinetic energy ion beams using Bradbury-Nielsen gates (BNGs) and their application to high duty cycle miniaturized mass spectrometry. We have developed methods to fabricate BNGs using template assisted manual weaving and silicon-on-insulator microfabrication. These devices have been characterized using ion beam imaging techniques, and the results compared to mathematical models of the deflection process developed for ... |
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| The Serret-Andoyer Formalism in Rigid-Body Dynamics: 1. Symmetries and Perturbations |
2007 |
38 pages |
| Authors:
P. Gurfil; A. Elipe; W. Tangren; M. Efroimsky; NAVAL OBSERVATORY WASHINGTON DC
|
| This paper reviews the Serret Andoyer (SA) canonical formalism in rigid-body dynamics, and presents some new results. As is well known, the problem of unsupported and unperturbed rigid rotator can be reduced. The availability of this reduction is offered by the underlying symmetry, that stems from conservation of the angular momentum and rotational kinetic energy. When a perturbation is turned on, these quantities are no longer preserved. Nonetheless, the language ... |
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| MURI Center for Materials Chemistry in the Space Environment |
30 NOV 2006 |
49 pages |
| Authors:
Steven J. Sibener; CHICAGO UNIV IL DEPT OF CHEMISTRY
|
| MURI research activities, involving strong interactions between experiment and theory, including interactions with AFRL, NASA, and Boeing, have advanced knowledge of condensed-phase and gas-phase reactions relevant to materials reactivity in LEO. We have: elucidated the mechanism by which graphite is eroded by high-kinetic energy atomic oxygen; quantified the pathways by which organic molecules react with atomic oxygen in regimes not found in the terrestrial environment; explored hyperthermal O chemistry with ... |
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| Aromatic Nylons for Transparent Armor Applications |
NOV 2006 |
9 pages |
| Authors:
John W. song; Joel Lofgren; Kyle D. Hart; Nick Tsantinis; Roy Paulson; Jay N. Hatfield; ARMY NATICK RESEARCH DEVELOPMENT AND ENGINEERING COMMAND MA NATICK SOLDIER CENTER
|
| Failure and kinetic energy absorption mechanisms upon ballistic impact of two new types of nylons, TROGAMID T-5000 (T-5000) and TROGAMIDCX7323 (CX-7323) as well as traditional materials such as polycarbonate (PC) and polymethylmethacrylate (PMMA) were examined and compared. Under ballistic impact, T-5000 showed brittle failure similar to PMMA, while CX-7323 exhibited ductile behavior similar to PC. Like PC and PMMA, the failure modes of T-5000 and CX-7323 are different from each ... |
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| High-Efficiency Helical Coil Electromagnetic Launcher |
31 AUG 2006 |
37 pages |
| Authors:
Thomas G. Engel; William C. Nunnally; John M. Gahl; MISSOURI UNIV-COLUMBIA DEPT OF ELECTRICAL ENGINEERING
|
| Technical progress during the reporting period includes the development of new theory for electromagnetic launcher efficiency which is applicable to all constant inductance gradient launcher geometries. This theory also develops methods to predict the performance of different geometry electromagnetic launchers and compare them to each other. A theoretical analysis is also presented to design a helical electromagnetic launcher for a specific volt- amp characteristic. Experimentally measured performance is reported for ... |
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| In Situ Experimental Studies of Fundamental Degradation Processes in the Low Earth Orbit Environment |
01 AUG 2006 |
22 pages |
| Authors:
Judith C. Yang; PITTSBURGH UNIV PA DEPT OF MATERIALS SCIENCE AND ENGINEERING
|
| The primary accomplishment of this MURI team was demonstrating that completed different oxides form due to exposure to hyperthermal atomic oxygen, and, hence, novel oxidation mechanisms are needed to explain such unusual oxide structures. ITO: the reactivity of AO causes recrystallization of the ITO nanograins along the interface between the ITO and substrate, which would negatively affect the film adhesion. Si: Remarkably homogeneous and uniform oxides form that are thicker ... |
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| The Development of a Stratospheric Real-Time Turbulence Modeling SystemScient |
07 JUL 2006 |
84 pages |
| Authors:
Yuh-Lang Lin; Paul S. Suffern; Michael L. Kaplan; Zachary G. Brown; Chad J. Ringley; Michael T. Kiefer; David R. Vollmer; NORTH CAROLINA STATE UNIV AT RALEIGH DEPT OF MARINE EARTH AND ATMOSPHERIC SCIENCES
|
| The research project focused on the development of an automated numerical prediction system for stratospheric turbulence. This involved modifying and testing a stratospheric mesoscale numerical model with observed initial data from several case studies. A sequence of events was simulated that likely organized environments favorable for stratospheric turbulence. This sequence involved the development of large amplitude hydrostatic gravity waves that in turn modified the lower stratospheric environment making it favorable ... |
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| Hit-to-Kill Guidance Algorithm for the Interception of Ballistic Missiles During the Boost Phase |
JUN 2006 |
157 pages |
| Authors:
IV Lukacas John A.; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| A near-optimal guidance law has been developed using the direct method of calculus of variations that maximizes the kinetic energy transfer from a surface-launched missile upon interception to a ballistic missile target during the boost phase of flight. Mathematical models of a North Korean Taep'o-dong II (TD-2) medium-range ballistic missile and a Raytheon Standard Missile 6 (SM-6) interceptor are used to demonstrate the guidance law's performance. This law will utilize ... |
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| Atomization in Gas-Centered Swirl-Coaxial Injectors (PREPRINT) |
08 MAR 2006 |
12 pages |
| Authors:
Malissa D. Lightfoot; S. A. Danczyk; D. G. Talley; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| A preliminary study of atomization mechanisms in gas-centered swirl-coaxial injectors for use in rocket engines has been undertaken. Gas-centered swirl-coaxial injectors differ from other injectors in that atomization occurs from a wall-bounded liquid. Few studies of atomization mechanisms in wall-bounded flows exist; some probable atomization processes have been determined, however. These mechanisms include liquid turbulence, aerodynamic stripping and a process driven by gas-phase structures. The likely character of the gas ... |
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| Atomization in Gas-Centered Swirl-Coaxial Injectors |
08 MAR 2006 |
12 pages |
| Authors:
M. D. Lightfoot; S. A. Danczyk; D. G. Talley; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| A preliminary study of atomization mechanisms in gas-centered swirl-coaxial injectors for use in rocket engines has been undertaken. Gas-centered swirl-coaxial injectors differ from other injectors in that atomization occurs from a wall-bounded liquid. Few studies of atomization mechanisms in wall-bounded flows exist; some probable atomization processes have been determined, however. These mechanisms include liquid turbulence, aerodynamic stripping and a process driven by gas-phase structures. The likely character of the gas ... |
|
| Plasma Radiation Source Development Program |
MAR 2006 |
188 pages |
| Authors:
Henry Sze; Phil Coleman; Bruce Failor; Jerry Levine; John Riordan; Yuanxu Song; Eduardo Waisman; MAXWELL PHYSICS INTERNATIONAL SAN LEANDRO CA
|
| This report summarizes the results of a 3 year effort to develop long implosion time (>150 ns) z-pinch loads for use on the planned Decade Quad (DQ) pulsed power generator. Well diagnosed experiments demonstrated high quality, 200 ns implosions using argon gas puff loads. We show that solid fill and double shell mass distributions perform better than thin shells. The dual plenum, double shell load has unique diagnostic features that ... |
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| Defense Acquisitions. Missile Defense Agency Fields Initial Capability but Falls Short of Original Goals |
MAR 2006 |
91 pages |
| Authors:
GOVERNMENT ACCOUNTABILITY OFFICE WASHINGTON DC
|
| MDA made good progress during fiscal year 2005 in the development and fielding of two of the seven elements reviewed. Most of the others encountered problems that slowed progress. Meanwhile, contractors for the seven elements exceeded their fiscal year budget by about $458 million, or about 14 percent, most of which was attributable to cost overruns in developing the Ground-based Midcourse Defense (GMD) element. Accelerating Block 2004 allowed MDA to ... |
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| Conservation of Lateral Momentum in Heterostructure Integrated Thermionic Coolers |
2006 |
16 pages |
| Authors:
Daryoosh Vashaee; Ali Shakouri; CALIFORNIA UNIV SANTA CRUZ SCHOOL OF ENGINEERING
|
| Thin film thermionic coolers use selective emission of hot electrons over a heterostructure barrier layer from emitter to collector resulting in evaporative cooling. In this paper a detailed theory of electron transport perpendicular to the multilayer superlattice structures is presented. Using Fermi-Dirac statistics, density-of-states for a finite quantum well and the quantum mechanical reflection coefficient, the current-voltage characteristics and the cooling power density are calculated. The resulting equations are valid ... |
|
| Heat Generation During the Firing of a Capacitor Based Railgun System |
2006 |
10 pages |
| Authors:
Andrew N. Smith; Benjamin T. McGlasson; Jack S. Bernardes; NAVAL ACADEMY ANNAPOLIS MD DEPT OF MECHANICAL ENGINEERING
|
| Railguns use a high-current, high-energy electrical pulse to accelerate projectiles to hypersonic velocities. Pulse forming networks that employ capacitors as the energy store are typically used to shape the required electrical pulse. A significant fraction of the stored energy (25 40% in large caliber railguns) is converted to projectile kinetic energy during launch. After the projectile exits the launcher, the balance of the energy has either been dissipated as heat ... |
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| Ordered and Highly Scalable Granular Media for Shock Mitigation |
SEP 2005 |
67 pages |
| Authors:
Robert Doney; Surajit Sen; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
|
| We provide an update to our current efforts in studying shock mitigation using one-dimensional arrays of adjacent metal spheres that may progressively shrink in size. These tapered chains are characterized by the number of spheres, N, the amount of tapering, q, and restitutive losses, . Spheres are assumed to interact via the nonlinear Hertz potential, V 5/2, where is the amount of overlap of adjacent grains and the constant of ... |
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| Continuous Hypergolic Monitor Network for Shipboard Applications |
30 AUG 2005 |
30 pages |
| Authors:
Minsa Todd; SEACOAST SCIENCE INC CARLSBAD CA
|
| Report developed under SBIR contract" for topic "MDA04-146" This report was developed under SBIR contract for topic MDA04-146. Seacoast Science Inc. has provided proof-of-concept technical results and proposed prototype design for the detection of hypergolic fuels and oxidizers for use in the MDA Kinetic Energy Interceptor (KEI) program. The proposed sensor system consists of three different sensor cases all containing a MEMS chemicapacitor sensor array. Seacoast's sensor technology utilizes an ... |
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| Performance Test Results for the Laser-Powered Microthruster (PREPRINT) |
30 AUG 2005 |
13 pages |
| Authors:
Claude R. Phipps; James R. Luke; Wesley Helgeson; Richard Johnson; PHOTONIC ASSOCIATES SANTA FE NM
|
| Microthrusters are useful for orienting and repositioning small craft above the atmosphere. We report technical results obtained during a successful 5-year program to develop a commercially-viable laser-powered microthruster. Its main advantage is the ability to generate a broad thrust range under programmable electronic control with minimal electrical power. The device applies millisecond-duration diode-laser pulses to a fuel tape to produce an ablation jet. By employing laser-initiated energetic polymers in our ... |
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| Ultrafast Laser Studies of Molecular Rydberg Wave Packets |
07 JUL 2005 |
5 pages |
| Authors:
Stephen R. Leone; Stefan Gilb; Vilen Nestorov; Elva Torres; Alan Arrowsmith; Dalziel Wilson; CALIFORNIA UNIV BERKELEY SPONSORED PROJECTS OFFICE
|
| The goal of this work is to investigate the formation and detection of Rydberg wave packets in molecules and to explore their possible use in quantum information processing. Very few coherent superpositions of molecular Rydberg states have been experimentally realized. Therefore, this research focuses on several new ways to produce coherent superpositions of Rydberg states in molecules as well as innovative methods to detect them by kinetic-energy resolved electron detection ... |
|
| Structure of 2-D and 3-D Turbulent Boundary Layers with Sparsely Distributed Roughness Elements |
28 JUN 2005 |
262 pages |
| Authors:
Jacob George; Roger L. Simpson; VIRGINIA POLYTECHNIC INST AND STATE UNIV BLACKSBURG DEPT OF AEROSPACE AND OCEAN ENGINEERING
|
| The present study deals with the effects of sparsely distributed three-dimensional elements on two-dimensional (2-D) and three-dimensional (3-D) turbulent boundary layers (TBL) in three parts: Part 1 with isolated cylinders in the turbulent boundary layers, thus considering the effect of a single perturbation on the TBL; Part 2 when the same individual elements were placed in a sparse and regular distribution, thus showing the response of the flow to a ... |
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| High Speed Linear Induction Motor Efficiency Optimization |
JUN 2005 |
|
| Authors:
Andrew P. Johnson; MASSACHUSETTS INST OF TECH CAMBRIDGE
|
| One of the reasons linear motors, a technology nearly a century old, have not been adopted for a large number of linear motion applications is that they have historically had poor efficiencies. This has restricted the progress of linear motor development. The concept of a linear motor as a rotary motor cut and laid out flat with a conventional rotary motor control scheme as a design basis may not be ... |
|
| Ionic Liquids Research and Development - US Air Force Research Laboratory. Molecular Dynamics Contractors Meeting |
24 MAY 2005 |
14 pages |
| Authors:
Tim Hawkins; Stefan Schneider; Angelo Alfano; Gammy Vaghjiani; Jeff Mills; Leslie Hall; Donald Tzeng; Jerry Boatz; AIR FORCE RESEARCH LAB EDWARDS AFB CA SPACE AND MISSILE PROPULSION DIV
|
| This documents reports on: 1) Recent Ionic Liquid Synthesis and Characterization; 2) Ionic Liquid Fuel for Biopropulsion; 3) Ionic Liquids in Munitions; 4) Energetic Ionic Liquids for TNT Replacements; and 5) Theoretical Performance. |
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| Jefferson Lab Free Electron Laser 10 kW Upgrade - Lessons Learned |
MAY 2005 |
49 pages |
| Authors:
B. W. Williams; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF PHYSICS
|
| The activities of the Free Electron Laser (FEL) Group at Thomas Jefferson National Accelerator Facility (JLab) in Newport News, Virginia, during the Infrared Demonstration Free Electron Laser Upgrade Project are summarized. The project spanned four years, from July 2000 to June 2004, and resulted in the upgrade from a 1 kW-class FEL to a 10 kW-class FEL at JLab. Lessons learned during the Upgrade are presented and discussed. |
|
| Recent Laser Propulsion Results from WSMR/HELSTF/PLVTS |
MAY 2005 |
43 pages |
| Authors:
Bill Larson; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| On our 31st trip to the laser facility at WSMR we carried out experiments on laser ablation of black and white Delrin ALSO CALLED POLYOXYMETHYLENE, POLYFORMALDEHYDE, (HCHO)x. Mass ablation and thrust generation (impulse) were accurately measured as a function of input laser energy in one shot experiments. The efficiency of conversion of laser energy to jet kinetic energy depended on the geometry of the energy absorption/conversion zone. The most ideal ... |
|
| FCS Vehicle Transportability, Survivability, and Reliability Analysis |
APR 2005 |
|
| Authors:
Cynthia Dion-Schwarz; Leon Hirsch; Phillip Koehn; Jenya Macheret; Dave Sparrow; INSTITUTE FOR DEFENSE ANALYSES ALEXANDRIA VA
|
| IDA investigated the Future Combat Systems' (FCS) Key Performance Parameters (KPPs) and their underlying Critical Technologies (CT's) to identify metrics to support Department-level monitoring of the FCS program and to gain an understanding of the implications of the KPPs (and their underlying CT's) upon the FCS program. This work focuses on the KPPs for Transportability and Sustainability/Reliability. The investigation into metrics for transportability revealed that the C130 Transportability requirement for ... |
|
| C++ Model Developer (CMD) User Guide |
APR 2005 |
123 pages |
| Authors:
George W. Snyder; Loretta Painter; Jeffrey W. Hester; George A. Sanders III; Ray Sells; Michael Fennell; ARMY AVIATION AND MISSILE COMMAND REDSTONE ARSENAL AL MISSILE RESEARCH DEVELOPMENT AND ENGINEERING CENTER
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| C++ Model Developer (CMD) is an open-source C++ source code based environment for building simulations of systems described by time-based differential equations. The principal design objective behind CMD is to provide a tool to go from mathematical representation to working, extensible C++ code with a minimum amount of effort. The heart of CMD is a powerful simulation kernel that represents significant technology advances in the application of object-oriented principles to ... |
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| Non-Adiabatic Energy Surfaces of the B+H2 Systems |
MAR 2005 |
78 pages |
| Authors:
Lachlan T. Belcher; AIR FORCE INST OF TECH WRIGHT-PATTERSONAFB OH
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| In order to solve the dynamics of a system, the kinetic energy operator of the Hamiltonian must be diagonalized. Diagonalization requires rotation of the system into a non-adiabatic representation. This rotation is a coupling angle determined by the derivative coupling terms. Derivative coupling terms are calculated using Columbus and Brooklyn, software packages. Separation of internal dynamics characterized by Jacobi coordinates, and external dynamics characterized by a set of Euler angles ... |
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| Barge Train Maximum Impact Forces Using Limit States for the Lashings Between Barges |
MAR 2005 |
124 pages |
| Authors:
Jose R. Arroyo; Robert M. Ebeling; ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS INFORMATION TECHNOLOGY LAB
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| In 1993, Headquarters, U.S. Army Corps of Engineers issued the first formal Corps-wide analysis procedure providing guidance for analyzing the effects of barge impact loading on navigation structures. According to the ETL 1110-2-338 engineering procedure, the magnitude of the impact forces generated by a particular collision event is dependent on: the mass including hydrodynamic added mass of the barge train, the approach velocity, the approach angle, the barge train moment ... |
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| Vertical Structure and Flux Formulations for the Stable Boundary Layer |
15 FEB 2005 |
3 pages |
| Authors:
Larry Mahrt; Dean Vickers; Cheryl Klipp; OREGON STATE UNIV CORVALLIS COLL OF OCEANIC AND ATMOSPHERIC SCIENCES
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| A z-less form of the mixing length that approaches surface layer similarity theory at the surface and approaches boundary layer similarity theory for weakly stratified conditions performed significantly better for CASES99 data than five other existing formulations, particularly after accounting for self- correlation. Radiative flux divergence was important for the initial formation of the surface inversion layer in CASES99, but was otherwise unimportant. Based on several data sets, the success ... |
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Reports by Keyword(s)
KINETIC ENERGY
