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U.S. Army Research Laboratory

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Works: 1,907 works in 2,402 publications in 1 language and 210,236 library holdings
Genres: Conference papers and proceedings 
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Most widely held works about U.S. Army Research Laboratory
 
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Most widely held works by U.S. Army Research Laboratory
A systems approach to the solid lubrication of foil air bearings for oil-free turbomachinery by Christopher DellaCorte( )

2 editions published in 2002 in English and held by 349 WorldCat member libraries worldwide

DFT study of H₂ combustion on [alpha]Al₂O₃ supported Pt clusters by Jennifer Synowczynski( )

2 editions published in 2008 in English and held by 330 WorldCat member libraries worldwide

Based on Density Functional Theory Generalized Gradient Approximation (DFT-GGA) calculations, we provide a theoretical model for the effect of the catalytic support (alpha alumina oxide (alphaAl2O3)) on the dissociation of molecular hydrogen (H2), molecular oxygen (O2), hydroxyl (OH), water (H2O), and the surface diffusion of oxygen and hydrogen species along the Al2O3 (0001) surface. These processes are key to understanding the inverse spillover effect that occurs during hydrogen combustion on alumina surfaces. Our results indicate the dissociation of O2 is not thermodynamically favored on the Al2O3 surface. However, both H2 and H2O can dissociate, forming hydroxyls with oxygen atoms in the second atomic layer. Once dissociated, oxygen species can diffuse locally but encounter a large barrier to long-range surface diffusion in the absence of defects or other species. In contrast, the barrier to the long-range surface diffusion of hydrogen is modest under ideal conditions
Developing CORBA-based distributed scientific applications from legacy Fortran programs by Janche Sang( )

2 editions published in 2000 in English and held by 330 WorldCat member libraries worldwide

Computerized design and generation of gear drives with a localized bearing contact and a low level of transmission errors by F. L Litvin( )

2 editions published in 1996 in English and held by 311 WorldCat member libraries worldwide

A general approach developed for the computerized simulation of loaded gear drives is presented. In this paper the methodology used to localize the bearing contact, provide a parabolic function of transmission errors, and simulate meshing and contact of unloaded gear drives is developed. The approach developed is applied to spur and helical gears, spiral bevel gears, face-gear drives, and worm-gear drives with cylindrical worms
Effects of planetary gear ratio on mean service life by M Savage( )

3 editions published between 1996 and 1997 in English and held by 311 WorldCat member libraries worldwide

Planetary gear transmissions are compact, high-power speed reductions which use parallel load paths. The range of possible reduction ratios is bounded from below and above by limits on the relative size of the planet gears. For a single plane transmission, the planet gear has no size at a ratio of two. As the ratio increases, so does the size of the planets relative to the sizes of the sun and ring. Which ratio is best for a planetary reduction can be resolved by studying a series of optimal designs. In this series, each design is obtained by maximizing the service life for a planetary with a fixed size, gear ratio, input speed power and materials. The planetary gear reduction service life is modeled as a function of the two-parameter Weibull distributed service lives of the bearings and gears in the reduction. Planet bearing life strongly influences the optimal reduction lives which point to an optimal planetary reduction ratio in the neighborhood of four to five
Dynamic analysis of spur gear transmissions (DANST) : PC version 3.00 user manual by Fred B Oswald( )

2 editions published in 1996 in English and held by 306 WorldCat member libraries worldwide

DANST is a FORTRAN computer program for static and dynamic analysis of spur gear systems. The program can be used for parametric studies to predict the static transmission error, dynamic load, tooth bending stress and other properties of spur gears as they are influenced by operating speed, torque, stiffness, damping, inertia, and tooth profile. DANST performs geometric modeling and dynamic analysis for low- or high-contact-ratio spur gears. DANST can simulate gear systems with contact ratios ranging from one to three. It was designed to be easy to use and it is extensively documented in several previous reports and by comments in the source code. This report describes installing and using a new PC version of DANST, covers input data requirements and presents examples
Computerized design and analysis of face-milled, uniform tooth height, spiral bevel gear drives by F. L Litvin( )

3 editions published in 1996 in English and held by 304 WorldCat member libraries worldwide

Face-milled spiral bevel gears with uniform tooth height are considered. An approach is proposed for the design of low noise and localized bearing contact of such gears. The approach is based on the mismatch of contacting surfaces and permits two types of bearing contact either directed longitudinally or across the surface to be obtained. A Tooth Contact Analysis (TCA) computer program was developed. This analysis was used to determine the influence of misalignment on meshing and contact of the spiral bevel gears. A numerical example that illustrates the developed theory is provided
Effectiveness of micro-blowing technique in adverse pressure gradients by Gerard E Welch( )

2 editions published in 2001 in English and held by 304 WorldCat member libraries worldwide

The impact of the micro-blowing technique (MBT) on the skin friction and total drag of a strut in a turbulent, strong adverse-pressure-gradient flow is assessed experimentally over a range of subsonic Mach numbers (0.3<M<0.7) and reduced blowing fractions (0<2F/C(f,0)<1.75). The MBT-treated strut is situated along the centerline of a symmetric 2-D diffuser with a static pressure rise coefficient of 0.6. In agreement with presented theory and earlier experiments in zero-pressure-gradient flows, the effusion of blowing air reduces skin friction significantly (e.g., by 60% at reduced blowing fractions near 1.75). The total drag of the treated strut with blowing is significantly lower than that of the treated strut in the limit of zero-blowing; further, the total drag is reduced below that of the baseline (solid-plate) strut, provided that the reduced blowing fractions are sufficiently high. The micro-blowing air is, however, deficient in streamwise momentum and the blowing leads to increased boundary-layer and wake thicknesses and shape factors. Diffuser performance metrics and wake surveys are used to discuss the impact of various levels of micro-blowing on the aerodynamic blockage and loss
Improving the performance of the structure-based connectionist network for diagnosis of helicopter gearboxes by Vinay B Jammu( )

3 editions published between 1996 and 1997 in English and held by 300 WorldCat member libraries worldwide

A diagnostic method is introduced for helicopter gearboxes that uses knowledge of the gearbox structure and characteristics of the features' of vibration to define the influences of faults on features. The structural influences' in this method are defined based on the root mean square value of vibration obtained from a simplified lumped-mass model of the gearbox. The structural influences are then converted to fuzzy variables, to account for the approximate nature of the lumped-mass model, and used as the weights of a connectionist network. Diagnosis in this Structure-Based Connectionist Network (SBCN) is performed by propagating the abnormal vibration features through the weights of SBCN to obtain fault possibility values for each component in the gearbox. Upon occurrence of misdiagnoses, the SBCN also has the ability to improve its diagnostic performance. For this, a supervised training method is presented which adapts the weights of SBCN to minimize the number of misdiagnoses. For experimental evaluation of the SBCN, vibration data from a OH-58A helicopter gearbox collected at NASA Lewis Research Center is used. Diagnostic results indicate that the SBCN is able to diagnose about 80% of the faults without training, and is able to improve its performance to nearly 100% after training
Three-dimensional flow field measurements in a transonic turbine by P. W Giel( )

2 editions published in 1996 in English and held by 299 WorldCat member libraries worldwide

Three dimensional flow field measurements are presented for a large scale transonic turbine blade cascade. Flow field total pressures and pitch and yaw flow angles were measured at an inlet Reynolds number of 1.0 x 10(exp 6) and at an isentropic exit Mach number of 1.3 in a low turbulence environment. Flow field data was obtained on five pitchwise/spanwise measurement planes, two upstream and three downstream of the cascade, each covering three blade pitches. Three hole boundary layer probes and five hole pitch/yaw probes were used to obtain data at over 1200 locations in each of the measurement planes. Blade and endwall static pressures were also measured at an inlet Reynolds number of 0.5 x 10(exp 6) and at an isentropic exit Mach number of 1.0. Tests were conducted in a linear cascade at the NASA Lewis Transonic Turbine Blade Cascade Facility. The test article was a turbine rotor with 136 deg of turning and an axial chord of 12.7 cm. The flow field in the cascade is highly three dimensional as a result of thick boundary layers at the test section inlet and because of the high degree of flow turning. The large scale allowed for very detailed measurements of both flow field and surface phenomena. The intent of the work is to provide benchmark quality data for CFD code and model verification
Applying the principles of the Government Performance and Results Act to the research and development function [electronic resource] : a case study submitted to the Office of Management and Budget by U.S. Army Research Laboratory( )

2 editions published in 1996 in Undetermined and English and held by 282 WorldCat member libraries worldwide

Thermal fatigue testing of ZrO₂-Y₂O₃ thermal barrier coating systems using a high power CO₂ laser by Dongming Zhu( )

2 editions published in 1997 in English and held by 257 WorldCat member libraries worldwide

The present state of amperometric nanowire sensors for chemical and biological detection by M. H Ervin( )

3 editions published in 2006 in English and held by 255 WorldCat member libraries worldwide

Focusing of dispersive targets using synthetic aperture radar by John McCorkle( )

2 editions published between 1994 and 2010 in English and held by 233 WorldCat member libraries worldwide

The focusing of synthetic aperture radar (SAR) data presents problems to the designer. This report addresses the SAR focusing problem with special attention to focusing an area in the near field of the synthetic aperture over a decade or more of bandwidth in a manner that preserves target resonance characteristics. A method for solving this image formation problem is described, along with a computationally efficient algorithm that is applicable to real-time processing with motion compensation. Simplified program examples are given, as well as a complete program listing that executes on several single-chip array processors simultaneously. An error analysis shows quantitatively when the depth of focus is adequate to preserve long-duration target resonance ringing effects for a given target Q, geometry, and bandwidth. SAR, UWB, Focusing radar
7th International Conference on Computer Communications and Networks : proceedings, October 12-15, 1998, Lafayette, Louisiana by International Conference on Computer Communications and Networks( )

5 editions published between 1998 and 2001 in English and held by 230 WorldCat member libraries worldwide

Aviator Behavior and Performance as Affected by Aircrew Life Support and Protective Equipment by John D Waugh( )

1 edition published in 1999 in English and held by 228 WorldCat member libraries worldwide

A methodology for quantifying Army rotary wing aviator performance as influenced by aircrew life support, survival, and nuclear-biological-chemical clothing and equipment ensembles was examined in a set of experiential trials conducted in an AH-64 (Apache) combat mission simulator. The methodology was based on an aircrew evaluation procedure originally developed for use in the crew coordination training of all Army aviators. It uses a set of 13 basic qualities, each with behavioral anchors and a 7-point rating scale, and it is administered by specifically trained senior aviator evaluators. Ten crews, two aviators in each, while fully encumbered, performed three combat missions for record, representative of typical operational tasks, with one "variation" trial conducted without the over-water components of the ensemble. Measures of effectiveness and flight data, as well as stress assessment and equipment "complaints" citations, were recorded. The results indicated that the behavior-anchored scores were not sensitive enough to statistically discriminate among the independent variables of repeated measures and the variation trials even though graphically, differences were readily apparent. Attempts to apply transformations to the data, based on the aviator subjects' relative flying experience and their apparent accommodation to the trials were also statistically unsuccessful. The additional measures collected did not yield statistically significant discriminations nor did they correlate well with the evaluation score. A number of options for improving the technique are offered
Experimental heat transfer and bulk air temperature measurements for a multipass internal cooling model with ribs and bleed by Douglas R Thurman( )

3 editions published in 2000 in English and held by 227 WorldCat member libraries worldwide

An experimental study was made to obtain heat transfer and air temperature data for a simple 3-leg serpentine test section that simulates a turbine blade internal cooling passage with trip strips and bleed holes. The objectives were to investigate the interaction of ribs and various bleed conditions on internal cooling and to gain a better understanding of bulk air temperature in an internal passage. Steady state heat transfer measurements were obtained using a transient technique with thermochromic liquid crystals. Trip strips were attached to one wall of the test section and were located either between or near the bleed holes. The bleed holes, used for film cooling, were metered to simulate the effect of external pressure on the turbine blade. Heat transfer enhancement was found to be greater for ribs near bleed holes compared to ribs between holes, and both configurations were affected slightly by bleed rates upstream. Air temperature measurements were taken at discreet locations along one leg of the model. Average bulk air temperatures were found to remain fairly constant along one leg of the model
A Proposed Modeling Protocol for Evaluating Information Attacks by John H Brand( )

1 edition published in 1999 in English and held by 226 WorldCat member libraries worldwide

The essence of an information attack is to alter, either by intrusion into and manipulation of a database or by deception, the scenario under which a target mind or organization evaluates and selects future courses of action. The aim is to influence the actions of the target. The method is alteration of the perceived desirability or expected payoff of specific courses of action. This alteration of the information in possession of the target can be described as alteration of the perceived reality under which the target operates. Probable success by an attacker in altering the target's perceived behavior, given a successful manipulation of the target's information, has, in the past, been subjective. A modeling protocol based on the use of game theory is proposed that may, in certain cases, allow optimization of the scenario, or reality, imposed on the target to force the choice of a desired course of action. It should also allow a quantitative estimate of the likelihood of the target's adopting a given course of action. This tool can be used to estimate friendly susceptibility to information attack
ARL Intranet Analysis and Development Study by Dana L Ulery( )

1 edition published in 1999 in English and held by 226 WorldCat member libraries worldwide

We analyze the concept and practice of Intranets used in midsize and large enterprises, focusing on their use and impact within research and development (R & D) organizations. We examine the shift from the old concept of business computing to the modern concept of enterprise computing, and consider Intranets-a class of enterprise computing-relative to enterprise computing trends. By analyzing in detail some case studies selected from the literature, on-site visits, and workshop discussions, we then offer three tools to frame the critical issues and provide structure for systematically constructing strategic Intranets specific to a given organization's mission and culture. Arguing that creation of an Intranet that projects an image of a world-class organization demands no less than a world-class enterprise that is strategically enabled through information technology, we then analyze the current U.S. Army Research Laboratory (ARL) Intranet and present a three-step action plan to expedite ARL's movement toward creation of such an Intranet
Time-Varying Electrostatic Modeling Techniques by David Hull( )

1 edition published in 1999 in English and held by 225 WorldCat member libraries worldwide

ARL developed computer models and modeling techniques based on the Method of Moments, and has used them for some time to study electrostatic fields associated with targets, terrain clutter, and sensors of interest. Recent extensions to these unique ARL capabilities allow some dynamic conditions to be modeled as a time series of quasi-static models. These new techniques have enabled us to study the extremely low-frequency (ELF) effects of rotating helicopter blades on both airborne and remote sensors. Examples show how a dynamic helicopter model can be used to compute time-varying airborne fieldmeter calibration factors for aircraft charge and atmospheric electric field measurements, and remote ELF electric fields which might be detected by passive surveillance sensors
 
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Audience level: 0.32 (from 0.02 for 2009-2010 ... to 0.61 for Organizati ...)

7th International Conference on Computer Communications and Networks : proceedings, October 12-15, 1998, Lafayette, Louisiana
Alternative Names

controlled identityU.S. Army Ballistic Research Laboratory

controlled identityUnited States. Army Laboratory Command

AMSRL

AMSRL (U.S. Army Research Laboratory)

ARL

ARL (U.S. Army Research Laboratory)

army research laboratory

Army Research Laboratory (U.S.)

Australia Aeronautical Research Laboratory

Australia. Dept. of Defence. Aeronautical Research Laboratory

Estats Units d'Amèrica. Army. Research Laboratory

United States Aeronautical Research Laboratories

United States Aeronautical Research Laboratory

United States. Air Force. Aeronautical Research Laboratories

United States. Army. Research Laboratory

United States Research Laboratory

United States. Wright Air Development Division. Aeronautical Research Laboratory

US Army Research Laboratory

USA Air Force Research Division Aeronautical Research Laboratory

USARL

USARL (U.S. Army Research Laboratory)

アメリカ陸軍研究所

美國陸軍研究實驗室

美國軍方調查實驗室

Languages
English (89)

Covers
2009-2010 Assessment of the Army Research Laboratory