| Dimensional Analysis and Self-Similarity Theory for Regenerative Liquid Propellant Guns |
JAN 2000 |
81 pages |
| Authors:
I. Kohlberg; T. P. Coffee; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
 | Regenerative liquid propellant guns (RLPGs) have been studied for many years. RLPG firings almost always show large, high-frequency pressure oscillations. To study this phenomenon, a fluid dynamics model of the combustion chamher/gun tube of an RLPG has been developed. High-frequency oscillations are generated naturally by the physics modeled in the code. Dimensional analysis has been applied to the governing equations to furnish insight into the dynamic ... |
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| Crew Systems Analysis of Unmanned Aerial Vehicle (UAV) Future Job and Tasking Environments |
JAN 2000 |
57 pages |
| Authors:
Michael J. Barnes; Beverly G. Knapp; Barry W. Tillman; Brett A. Walters; Darlene Velicki; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| The purpose of the research project was to understand the future crew environments for developing unmanned aerial vehicle (UAV) systems. A variety of human engineering tools job assessment software system JASS, enhanced computer- aided testing ECAT, and MicroSaint(Trademark)) were used to address crew issues related to the utility of having rated aviators as crew members, supplementing current crews with imagery and intelligence specialists, and the use ... |
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| Measurement of Viscosity of Reacting Vinyl-Ester Resins Using Direct- Current Sensing |
JAN 2000 |
45 pages |
| Authors:
Bruce K. Fink; Kenric M. England; John W. Gillespie Jr; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| This study investigated the sensing of viscosity an gelation of reacting vinyl-ester (VE) resins using direct-current (DC) sensing technology. The resin system studied was a tetrabutylammonium acetate (TA)-doped Dow Derakane 411-C-50 VE resin. A model of the resistance of a reacting polymer liquid as a function of the geometrical parameters of the DC-sensing system and the material properties of the resin system was developed. The ... |
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| Co-Injection Resin Transfer Molding of Vinyl-Ester and Phenolic Composites |
JAN 2000 |
37 pages |
| Authors:
Bruce K. Fink; Emanuele F. Gillio; Geoffrey P. McKnight; John W. Gillespie Jr.; Suresh G. Advani; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| Vacuum-assisted resin transfer molding (VARTM)-type processes have been proven cost-effective manufacturing techniques for large composite structures. However, their use has been limited to a single resin system. Many composite structures require multiple resins to serve different purposes while being integrated into a single structure. Co-injection resin transfer molding (CIRTM) is a new manufacturing process developed by the U.S. Army Research Laboratory (ARL) with the ... |
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| Performance Metrics for Parallel Systems |
JAN 2000 |
33 pages |
| Authors:
D. M. Pressel; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| One frequently needs to compare the performance of two or more parallel computers, but how should this be done? The most straightforward way to do this would be to rely upon a suite of benchmarks. Unfortunately, there are many problems and limitations with this approach. Therefore, one is frequently forced to rely upon a combination of approaches. Unfortunately, many of the alternative approaches are all too ... |
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| The Design Constraints for the Memory Systems of Useful SMPs |
JAN 2000 |
27 pages |
| Authors:
D. M. Pressel; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| In recent years, many vendors have produced cache coherent shared memory symmetric multiprocessors. While most of the systems that used, at most, eight processors have been successes, the same statement cannot be made for the larger, more scalable systems. Some of the larger systems have been extremely successful, others have been marginally to reasonably successful, and a few have been outright failures. Based on the author's ... |
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| Design of a Resistive Susceptor for Uniform Heating During Induction Bonding of Composites |
JAN 2000 |
45 pages |
| Authors:
Bruce K. Fink; Shridhar Yarlagadda; John W. Gillespie Jr; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| A novel susceptor concept for metal-mesh susceptors, designed to achieve uniform in-plane temperatures during induction heating, is documented. The process involves redirecting eddy-current flow patterns in the resistive- mesh susceptor by specifically designed cut patterns in the mesh. A theoretical model was developed to predict heat generation in metal-mesh susceptors with any described network pattern. initial results for cut patterns show significant changes in heating ... |
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| The True Limitations of Shared Memory Programming |
JAN 2000 |
31 pages |
| Authors:
D. M. Pressel; M. Behr; S. Thompson; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| Shared memory parallel computers have the reputation for being the easiest type of parallel computers to program. At the same time, they are frequently regarded as being the least scalable type of parallel computer. In particular, shared memory parallel computers are frequently programmed using a form of loop-level parallelism (usually based on some combination of compiler directives and automatic parallelization). However, in discussing this form ... |
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| Diode Laser Measurements of HF Concentrations From Heptane/Air Pan FiresExtinguished by FE-36 and FE-36 Plus APP |
JAN 2000 |
30 pages |
| Authors:
R. R. Skaggs; R. G. Daniel; A. W. Miziolek; K. L. McNesby; C. Herud; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| Tunable diode laser absorption spectroscopy (TDLAS) is used to measure the time evolution of hydrogen fluoride (HF) concentrations produced from a series of enclosed heptane/air pan fires extinguished by FE-36 or FE-36 plus ammonium polyphosphate (APP). Recent advances in room temperature fiber coupled near infrared (NIR) diode lasers provide isolation of the laser and signal processing electronics from the hostile sampling site. For the fires ... |
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| Results of 35-mm Airburst Demonstration |
JAN 2000 |
65 pages |
| Authors:
Timothy G. Farrand; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| The U.S. Government and several industry representatives collaborated to initiate a demonstration of the current 35-mm airburst technology. The U.S. Government gathered an initial baseline database of "off-the-shelf" airburst technology, while industry was given the opportunity to demonstrate the performance of their airbursting munitions to U.S. and foreign government organizations and to numerous users. Two 35-mm airburst projectiles were evaluated, the Oerlikon Contraves AHEAD projectile ... |
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| Data Replication in Low Bandwidth Military Environments - State of the Art Review |
2000 |
10 pages |
| Authors:
Allan Gibb; Sam Chamberlain; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| Modern armies are undergoing a revolution in the way information is managed on the battlefield. Voice-based command, control, and communication systems are being complemented by, and in some cases replaced by (in whole or in part) digital command, control and communication systems. Digital systems offer the promise of increased battlefield awareness through a more systematic and automated distribution of relevant data than is possible with a voice-based communication system. To ... |
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| An Experimental Testbed for Battle Planning |
2000 |
18 pages |
| Authors:
Barry Bodt; Joan Forester; Charles Hansen; Eric Heilman; Richard Kaste; Janet O'May; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| This paper describes a modular evaluation testbed for Army Course Of Action (COA) Analysis (COAA), with emphasis on research into assessing the feasibility of COAs developed using a simplistic wargaming mechanism. Central to the project is the use of a realistic combat simulation to produce detailed COA evaluation. Components of the testbed include the COA generator Fox-GA (developed under the auspices of ARL's Federated Laboratory and based on genetic algorithm ... |
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| Revitalizing Battle Staff Training |
DEC 1999 |
215 pages |
| Authors:
Karol G. Ross; Linda G. Pierce; Marie C. Baehr; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| The Depth and Simultaneous Attack Battle Laboratory (D&SABL) and the U.S. Army Research Laboratory (ARL) are in a position to bring advanced training technology into fire support institutional training. Using D&SABL resources to introduce and refine scientifically based learning research findings as well as supporting technology will help guide decisions about resource investments for new technology and further experimentation. Toward that end, D&SABL and ARL ... |
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| The Effect of a Simple Lateral Impulse on Kinetic Energy Projectiles in Flight |
DEC 1999 |
55 pages |
| Authors:
Bernard J. Guidos; Gene R. Cooper; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| Existing analytical theory for quantifying the free-flight motion of non-rolling, statically stable projectiles is extended to include the effect of a simple lateral impulse applied during flight. The extended theory is based on the incorporation of generalized lateral translational and angular disturbances into the familiar equations of projectile free-flight motion. The applied disturbances are then modeled using specified mathematical forms, and the modified equations ... |
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| Advanced Gun System (AGS) Dynamic Characterization: Modal Test and Analysis, High-Frequency Analysis |
DEC 1999 |
94 pages |
| Authors:
Morris Berman; Ting Li; Abraham Frydman; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| Dynamic characterization tests were performed on the Advanced Gun System (AGS) vehicle. The tests were designed to provide modeling information for high-frequency shock prediction codes, as well as finite element codes. These data obtained were also used to validate the modeling codes. The vehicle was analyzed in a full-up condition with the turret attached. A model analysis was performed to a maximum frequency of 100 ... |
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| Non-Polluting Composites Repair and Remanufacturing for Military Applications: An Environmental and Cost-Savings Analysis |
DEC 1999 |
103 pages |
| Authors:
Bruce K. Fink; Steven H. McKnight; Crystal H. Newton; John W. Gillespie Jr.; Giuseppe R. Palmese; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| Polymer-matrix composite material and structural adhesive repair and manufacturing have significant environmental costs for Department of Defense (DOD) use. 'The principal issues for reducing environmental costs are (1) reducing hazardous waste by eliminating shelf-life limitations; (2) reducing nitrogen oxides (NOx) by replacing global heating of the part with localized heating; (3) reducing volatile organic compound (VOC) emissions by accelerated curing and containment; and (4) ... |
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| The Role of Transverse Flow in Co-Injection Resin Transfer Molding |
DEC 1999 |
39 pages |
| Authors:
Bruce K. Fink; Emanuele F. Gillio; Surresh G. Advani; John W. Gillespie Jr.; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| A co-injection resin transfer molding (CIRTM) process has been developed at the U.S. Army Research Laboratory (ARL) in collaboration with the University of Delaware. It enables two or more resins to be simultaneously injected into a mold filled with a stationary fiber preform. This process allows for the manufacturing of cocured multilayer multiresin structures in a single processing step. A separation layer is used to provide ... |
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| Epoxy Functionalized Hyberbranched Polymer/Epoxy Blends |
DEC 1999 |
29 pages |
| Authors:
Thomas J. Mulkern; Donovan Harris; Alan R. Teets; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| In this preliminary study, two novel hyperbranched polymer (HBP)/ epoxy blends were evaluated to determine their efficiency as blend modifiers and tougheners in a brittle epoxy resin. The HBP is miscible in the epoxy and phase separates as cure progresses to form a two-phase system with a dispersed secondary phase of HBP/epoxy compatibilizers in a rigid epoxy matrix. There is no significant increase in the viscosity ... |
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| Design and Analysis of a Fuze-Configurable Range Correction Device for an Artillery Projectile |
DEC 1999 |
71 pages |
| Authors:
Michael S. Hollis; Fred J. Brandon; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| The primary purpose of the low cost competent munitions (LCCM) program was to improve the effectiveness of indirect fire support from cannon artillery (D'Amico 1996). With the advances in microelectronics, sensor technology, and packaging design, the reality of a range correction device for artillery is conceivable. One of the main objectives of the range correction device concept was to contain all the mechanical and electrical ... |
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| The Effects of the Command and Control Vehicle (C2V) Operational Environment on Soldier Health and Performance |
NOV 1999 |
61 pages |
| Authors:
Patricia S. Cowings; William B. Toscano; Charles DeRoshia; Richard A. Tauson; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| The command and control vehicle (C2V) was developed to support U.S. Army tactical operation centers in heavy forces. The requirements for the C2V stipulate that it must support mobile operations and that it must support command and control (C2) from within the confines of the vehicle. However, in early testing, some human operators exhibited motion sickness during moving operations. As a result, the Human Research ... |
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| Munitions Survivability Technology: A Comparison of the Effectiveness ofTwo Different Blanket Designs for Protecting Against an Indirect Fragment Threat |
NOV 1999 |
31 pages |
| Authors:
Vincent M. Boyle; Alfred L. Bines; William B. Sutherland; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| This report describes the results of tests comparing the ballistic effectiveness of two types of Kevlar blanket when impacted by a steel fragment weighing 0.66 lb and having a velocity of 450 ft/s. This fragment, a right circular cylinder, was used to simulate the weight and velocity of a fragment that could be generated when a stack of barricaded M107 munitions detonates and throws fragments ... |
|
| Proceedings of the Fourth Annual U.S. Army Conference on Applied Statistics, 21-23 October 1998 |
NOV 1999 |
227 pages |
| Authors:
Barry A. Bodt; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| The fourth U.S. Army Conference on Applied Statistics was hosted by the U.S. Army Training and Doctrine Command (TRADOC) Analysis Center - White Sands Missile Range (TRAC-WSMR) during 21-23 October 1998. Two sites were used for the conference. The meeting began at the Corbett Center on the campus of New Mexico State University in Las Cruces and concluded at WSMR. me conference was cosponsored by the ... |
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| Intergranular Cracking in High-Strength, Cold-Rolled, and Precipitation-Hardened Austenitic Stainless Steel UNS S35500 |
NOV 1999 |
31 pages |
| Authors:
Sharad P. Pednekar; Victor K. Champagne; Marc S. Pepi; Scott Grendhal; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| When quench annealed, stainless steel UNS 35500 (C 0.12, Cr 15.5, Ni 4.5, Mo 3, N 0.1%) is austenitic and soft. In cold-rolled and tempered condition, heavy cold rolling followed by precipitation hardening considerably strengthens the material (UTS 220 ksi 1517 MPa, elongation 10%). Its strength, combined with good corrosion resistance, makes the material attractive for use in critical load-bearing applications. In one application, helicopter ... |
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| T-55 Engine Compressor Stator Vane Investigation |
NOV 1999 |
69 pages |
| Authors:
Scott M. Grendahl; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| The U.S. Army Aviation and Missile Command (AMCOM) requested the U.S. Army Research Laboratory Weapons and Materials Research Directorate (ARL-WMRD) investigate a corrosion problem with T-55 engine stators. This investigation was part of a second source vendor qualification in which a specific vendor was failing the engine test due to significant corrosion. The stators were virtually identical before the engine test and seemingly had passed all qualification ... |
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| Laser-Induced Breakdown Spectroscopy (LIBS) for Real-Time Detection of Halon Alternative Agents |
NOV 1999 |
35 pages |
| Authors:
Cynthia K. Williamson; Robert G. Daniel; Kevin L. McNesby; Andrzej W. Miziolek; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| We report results of an evaluation of laser-induced breakdown spectroscopy (LIBS) for the detection of candidate halon replacement compounds (CF4, CF3H, CF2H2, and C2F3H). The fundamental (1.064 micrometers) from a Nd:YAG Q-switched pulsed laser was focused into an air flow containing 0.0005-5% of the analyte halocarbon compounds. The laser-produced plasma emission consists of a large number of intense fluorine atom lines in the 600-850-nm spectral range. ... |
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| Non-Polluting Composites Repair and Remanufacturing for Military Applications: Induction-Based Repair of Integral Armor |
NOV 1999 |
55 pages |
| Authors:
Bruce K. Fink; Steven H. McKnight; Shridhar Yarlagadda; John W. Gillespie Jr.; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| Polymer-matrix composite material and structural adhesive repair and manufacturing have significant environmental costs. These costs have recently been documented based on current and anticipated future Department of Defense (DoD) use of these materials. The principal issues for reducing the environmental impact and its associated cost are: (1) reduction in hazardous waste by eliminating shelf-life limitations, (2) reduction in nitrogen oxides (NO(x)) by replacing ... |
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| Development of a Distributed Direct Current Sensor System for Intelligent Resin Transfer Molding |
NOV 1999 |
51 pages |
| Authors:
Bruce K. Fink; Roderic C. Don; John W. Gillespie Jr.; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| Resin transfer molding (RTM) and other liquid molding techniques hold the promise of affordable manufacturing for a variety of critical Army applications including the Composite Armored Vehicle (CAV) and Comanche helicopter. A critical barrier to the development of a quality control system and to our ability to consistently manufacture quality parts using RTM is the availability of an integration-friendly and cost-friendly flow and cure sensing ... |
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| Induction Heating of Carbon-Fiber Composites: Electrical Potential Distribution Model |
NOV 1999 |
45 pages |
| Authors:
Bruce K. Fink; Roy L. McCullough; John W. Gillespie Jr.; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| Mechanisms of heat generation and distribution in carbon-fiber-based composites subjected to an alternating magnetic field are considered. A model that predicts the strength and distribution of these heat sources in the plane of the cross-ply laminate configurations has been developed and verified. In this analysis, the fibers in a cross-ply pair are treated as a grid of conductive loops in the plane. Each such conductive ... |
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| A Semiclassical Study of Tunneling Effects in Aziridine |
NOV 1999 |
31 pages |
| Authors:
Yin Guo; Angela K. Wilson; Cary F. Chabalowski; Donald L. Thompson; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| The tunneling effects in the molecular inversion of aziridine are investigated. A full-dimensional potential was constructed based on ab initio results and used to study the effect of vibrational excitations on tunneling. Using the semiclassical approach that incorporates tunneling into classical trajectory calculations, it is found that excitations of all the modes except the reaction coordinate have negligible effects on tunneling. This allows accurate ... |
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| Non-Polluting Composites Repair and Remanufacturing for Military Applications: Co-Injection Resin Transfer Molding |
NOV 1999 |
57 pages |
| Authors:
Bruce K. Fink; John W. Gillespie Jr; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| Vacuum-assisted resin transfer molding (VARTM) processes have been proven to be cost-effective manufacturing techniques for large composite structures. However, their use has been limited to single resin systems. A large variety of composite structures requires multiple resins to serve different purposes while being integrated into a single structure. Significant environmental cost savings are possible by replacing currently practiced sequential repair and manufacturing techniques with reduced-step ... |
|
| Army Plasma/Propellant Interaction Workshop - U.S. Army Research Office,17-18 November 1998 |
NOV 1999 |
57 pages |
| Authors:
Robert W. Shaw; David M. Mann; William R. Anderson; Kevin White; Michael J. Nusca; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| This workshop was organized by the U.S. Army Research Office (ARO) as part of an ongoing U.S. Army Research Laboratory (ARL)-ARO effort to develop a coordinated research program to address the needs of advanced gun propulsion, in particular, in the application of plasmas as ignition and energy augmentation sources for solid propellant guns, known as electrothermal-chemical (ETC) propulsion systems. We sought to bring leading scientists and engineers ... |
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| 155-MM Howitzer Malfunction Investigation: A Laboratory Study of the Igniter Train Operation |
NOV 1999 |
63 pages |
| Authors:
Kevin J. White; Roger E. Bowman; Ingo W. May; Richard Hartman; Emerson V. Clarke; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| On 20 December 1974, two hangfires occurred in a developmental 155-mm howitzer at Aberdeen Proving Ground (APG), MD. The second hangfire was accompanied by a rupturing of the howitzer breech. As a result of this, a laboratory study was initiated to uncover possible causes leading to the malfunction. The study involved testing of various components of the igniter train singly and in various combinations under a ... |
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| Mechanical and Ballistic Properties of Composites of Polypyrrole-Coated S-2 Glass Fabrics |
OCT 1999 |
57 pages |
| Authors:
William A. Spurgeon; J. R. Klinger; Margaret E. Roylance; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| This report presents the results of mechanical and ballistic tests on polyester and polyurethane-based composites of polypyrrole-coated 5-2 glass fabrics. The fabrics were obtained from the Milliken Research Corporation, Spartanburg, SC. The data support the proposition that the glass fibers are, at most, slightly damaged by the coating process that requires an acidic solution of pH 1. The mechanical properties of the interface between the glass ... |
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| Effects of Coatings on Moisture Absorption in Composite Materials |
OCT 1999 |
47 pages |
| Authors:
James R. Newill; Steven H. McKnight; Christopher P. Hoppel; Gene R. Cooper; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| Polymeric coatings can he used to slow the ingress of moisture in composite materials. The effectiveness of these coatings is limited by the quality and thickness, as well as the moisture diffusivity and solubility. The present study investigates the long-term effectiveness of coatings for thick composite laminates, as well as traditional thin laminates. The results are compared for static and fluctuating boundary conditions, with comparisons ... |
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| Accelerated Adhesive Curing for Induction-Based Repair of Composites |
OCT 1999 |
37 pages |
| Authors:
Steven H. McKnight; Bruce K. Fink; Sean Wells; Shridhar Yarlagadda; John W. Gillespie Jr; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| A methodology for accelerated curing of commercially available room- temperature curing paste adhesives is outlined. Cure kinetics of the adhesive were studied by thermochemical analysis, and degree of cure was related to processing parameters and cure cycles. Increasing the cure temperature to 100 degrees C reduced the cure time from 16 hr to approximately 15 min. for 98% cure. Induction-heating techniques were used to demonstrate ... |
|
| Dendritic Polymers as Fire Suppressants |
OCT 1999 |
39 pages |
| Authors:
Nora C. Beck Tan; Daniel C. DeSchepper; Lajos Balogh; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| This report describes an evaluation of the applicability of one of the latest advances in polymer technology (dendritic polymers) to suppressing fires, one of the greatest survivability threats to military personnel and vehicles. Certain types of alkali and transition metal complexes are known to have the capability to act as fire suppression super-agents. Unfortunately, the most effective of these agents are also highly toxic. Dendritic ... |
|
| Spatially Resolved Combustion Species and Temperatures of Solid Propellant Flames Using Snapshot Spectroscopy |
OCT 1999 |
32 pages |
| Authors:
Barrie E. Homan; John A. Vanderhoff; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| Experimental improvements have been made in the ultraviolet (UV)- visible absorption spectroscopy technique applied to propellant flame diagnostics. The two-dimensional (2-D) feature of an intensified charge-coupled device (ICCD) detector was used to simultaneously record multiple, spatially distinct absorption spectra over a region of 0.35 cm. Temporal resolution has been increased to 1 ms by pulsing a simmering xenon arc lamp. The resulting increase ... |
|
| Elastomers for Tracked Vehicles - Development of Rubber Compounds for Bushings |
OCT 1999 |
47 pages |
| Authors:
Gumersindo Rodriguez; Paul Touchet; Alan R. Teets; David P. Flanagan; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| After development of HNBR12, a patented formulation that doubled the service life of track pads, it has become necessary to improve the service life of bushings and roadwheels. The purpose of the work during FY 98 was to increase the service life of bushings and close the gap in service life between pads and bushings, while work during FY 99 will address the service life of roadwheels. ... |
|
| How Moderate-Sized RIS C-Based SMPs Can Outperform Much Larger Distributed Memory MPPs |
OCT 1999 |
35 pages |
| Authors:
D. M. Pressel; Walter B. Sturek; J. Sahu; K. R. Heavey; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| Historically, comparisons between computer systems were based primarily on theoretical peak performance. Today, comparisons based on delivered levels of performance are frequently used. This, of course, raises a whole host of questions concerning methodology. From the standpoint of the user, delivered performance frequently refers to how fast a job runs. However, is it reasonable to base this measurement on running the same algorithm on all of the computers? When comparing ... |
|
| An Exploratory Study on a High-Energy Flux (HEF) Calorimeter to Characterize Flammability of Advanced Engineered Polymers: Phase 1 - Ignition and Mass Loss Rate |
OCT 1999 |
103 pages |
| Authors:
Archibald Tewarson; Wai Chin; Richard Shuford; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| This report describes a newly designed high-energy flux (HEF) calorimeter for the flammability evaluation of high fire resistant plastics exposed to high heat flux typical of combat field scenarios and large-scale fires. Small samples are exposed to heat fluxes as high as 150 kW/m2 in co- flowing air with oxygen concentration in the range of 0-100%. A pilot flame ignites the vapors, a load cell measures mass loss, and an ... |
|
| Chemical Analysis of Floor Sweepings from Aberdeen Proving Ground Building 1107 |
OCT 1999 |
24 pages |
| Authors:
Rose A. Pesce-Rodriguez; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| A sampling of floor sweepings taken from Building 1107 of the Aberdeen Proving Ground (APG) was provided for analysis with the request that it be examined for the presence of energetic materials. An analysis was performed using a desorption/pyrolysis-gas chromatography-mass spectroscopy (GC-MS) and differential scanning calorimetry (DSC). No evidence of the presence of energetic materials in the sample was found. |
|
| Calculating the Chemical Compositions of Plasmas Generated by an Ablating-Capillary Arc |
SEP 1999 |
49 pages |
| Authors:
M. J. McQuaid; M. J. Nusca; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| The NASA-Lewis computer program for the calculation of complex chemical equilibrium compositions (CEA) is proposed as a means of characterizing the compositions of plasmas generated via an ablating-capillary arc. Results obtained with CEA are compared to those obtained with a Saha equation-based (SE) model with a limited reaction product set. Case studies conducted at temperatures from 5,000 to 20,000 K and pressures from 10 to 200 bar ... |
|
| A New Virial-Theorem-Based Semi-Ab-Initio Method for Atomistic Simulations |
SEP 1999 |
32 pages |
| Authors:
Genrich L. Krasko; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| A new semi-ab-initio method for atomistic simulations based on the virial theorem has been suggested. The method is completely within the realm of the density-functional theory and uses the so-called "reduced" electron spin- density functional (SDF). The crucial component of the method is the ansatz expressing (for both one-component and two-component systems) the electron density at point r as a superposition of "atomic" densities due ... |
|
| An Investigation of the Erosion Physics/Mechanisms of Current Army Systems (Point Studies) |
SEP 1999 |
57 pages |
| Authors:
Paul J. Conroy; Paul Weinacht; Michael J. Nusca; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| Future systems performance requirements have led to a heightened awareness of the erosion issue and to the development of erosion investigations in the U.S. Army and Navy. These investigations involve experimental and modeling efforts to understand the thermal, chemical, and mechanical contributions to erosion/wear. A description of the mechanistic erosion representation follows in this report. The calculation procedure is illustrated, including details of the mass transport scheme, gas surface interface, ... |
|
| Flat Fire Jump Performance of a 155-mm M198 Howitzer |
SEP 1999 |
51 pages |
| Authors:
James M. Garner; Bernard J. Guidos; Keith P. Soencksen; David W. Webb; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| A jump experiment and analysis were performed for the M198 howitzer firing the M107 shell through short range, flat fire trajectories with a launch Mach number near 1.7. The objective was to characterize the jump performance of the system and provide a basis for identifying and possibly improving the largest contributors to jump over a broader range of firing conditions. For the short range, flat fire scenario of the present ... |
|
| Water-Dispersible Polyurethane Coating Test Protocol |
SEP 1999 |
|
| Authors:
Christopher Miller; John Escarsega; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
 | The Coatings Technology Team of the Polymers Research Branch has developed a water-reducible 180-g/L volatile organic compound (VOC) formulation that is also a chemical agent resistant coating (CARC). This report describes the substrates, pretreatments, and primers to be used in comparative testing of the new formulation vs. current CARC. The tests and evaluation criteria will also be introduced. This report will be used as a reference for the data presentation ... |
|
| Atomistic Simulation of Sigma 3 (111) Grain Boundary Fracture in Tungsten Containing Various Impurities |
SEP 1999 |
44 pages |
| Authors:
M. Grujicic; H. Zhao; G. L. Krasko; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
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| The effect of various impurities and micro-alloying additions (B, N, C, O, Al, Si, S, and P) on the intrinsic resistance of the sigma 3 (111) grain boundary in tungsten has been investigated using the molecular dynamics simulation. The atomic interactions have been accounted for through the use of Finnis-Sinclair interatomic potentials. The fracture resistance of the grain boundary has been characterized by computing, in each case, the ideal work ... |
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| Evaluation of Obturator and Sealing Cuff Properties for the M865 Training Projectile with Comparison to Ballistic Testing |
SEP 1999 |
51 pages |
| Authors:
C. P. Hoppel; J. F. Newill; K. P. Soencksen; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
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| The nylon obturation and RTV sealing cuff for the M865 training round were evaluated to identity potential sources of ballistic variability associated with the material properties and material processing. While the properties of these materials are strongly dependent on processing conditions, temperature, and moisture content, the M865 performance variability is reduced by a well- engineered fracture mechanism that focuses the stresses in the obturation during sabot discard. A ballistic test ... |
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| Hypervelocity Penetration Impacts in Concrete Targets |
SEP 1999 |
47 pages |
| Authors:
Alexander E. Zielinski; Graham F. Silsby; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
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| Electromagnetic launch offers the acceleration of projectiles to velocities larger than those provided by conventional chemical guns. The potential effect of large-impact energies on targets other than armor has great promise for replacing high-explosive (HE) payloads with inert hypervelocity rounds. A double-layer reinforced concrete (DLRC) wall, which has been reduced in scale, was the target. Tests were conducted with aluminum cylindrical projectiles launched at velocities up to 2,223 m/s for ... |
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| Analysis of Russian "Vertex" High-Strength Glass Fiber |
SEP 1999 |
51 pages |
| Authors:
William A. Spurgeon; Elias J. Rigas; Matthew S. Burkins; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
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| This report presents the results of mechanical and ballistic tests required in MIL-PRF-46l9?A (U.S. Department of the Army, "A Laminate, High Strength Glass Fiber Reinforced Polyester Resin," U.S. Army Research Laboratory, Aberdeen Proving Ground, MD, 16 April 1997) on Russian Vertex high-strength glass that is supposed to be equivalent to domestic S-2 glass. The results of tensile tests of 250-yield yarns of both types of fibers were very similar, with ... |
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