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Viewing 1 to 16 of 16
2006-04-03
Technical Paper
2006-01-0091
Zhenning Cao, Pingsha Dong
In the new design, the electrode employs composite electrode face construction with dissimilar materials. A cylindrical insert located in the electrode face center is made of low thermal and electrical conductivity material, such as stainless steel, and an annular outer sleeve is made of stainless steel and located at periphery of the electrode. Base material of the electrode is still made of copper alloys. With this electrode design, the electrical-thermal-mechanical conditions can be improved by confining the current flow path to reduce current level required for the weld nugget formation, and optimizing electrode pressure distribution, and minimizing electrode face heating and plastic deformation.
2011-06-13
Technical Paper
2011-38-0085
Satya P. Chauhan, Melissa Roshon, W. D. Samuels, H. Nick Conkle, Elizabeth Berman, Mary Wyderski
Currently the U. S. Department of Defense (DoD) exclusively uses potassium acetate (KAc)-based runway deicing fluids (RDFs) to deice and anti-ice military runways and taxiways. Commercial airports predominantly use KAc, but some also use RDFs composed of KAc plus propylene glycol (PG) or urea plus PG. Conventional RDFs have environmental concerns due to toxicity as well as material compatibility problems such as corrosion of aircraft carbon brake-pad components, cadmium-plated landing gear, and airfield lighting fixtures. Under the Strategic Environmental Research and Development Program (SERDP), Battelle tested a series of patented - bio-based RDFs to address these issues. Tests showed that the Battelle RDFs met the mandatory Aerospace Material Specification (AMS) 1435 requirements. These new RDFs have reduced ecotoxicity compared to currently used RDFs and are compliant with all other environmental requirements.
1998-04-08
Technical Paper
981506
Jeong K. Hong, Pingsha Dong, Fredrick Brust, Thomas Forte
This paper presents a numerical analysis of the effect of weld induced residual stress on the fatigue behavior of a T-joint. The thick-section T-joint contained 18 individual weld passes and was subjected to fully-reversed, zero-maximum, and zero-minimum fatigue cycling. The effect of the residual stress was demonstrated by comparing the result with and without residual stress. It was concluded that the local fatigue parameters (mean stress, alternating stress, and stress ratio) at the suspected crack initiation site were changed significantly by the residual stresses when the applied stress were other than fully reversed. In addition, the effect of the stress concentration at the weld was more significant that the effect of the residual stress for the applied fatigue loads levels that were considered. The analysis method presented can be used to assess weldment design and process variables.
2003-05-19
Technical Paper
2003-01-2022
John E. Orban, Hsing-Chuan Tsai, Shawn D. Whitacre
The Advanced Petroleum-Based Fuels - Diesel Emissions Control (APBF-DEC) project is a joint U.S. government/industry research effort to identify optimal combinations of fuels, lubricants, engines, and emission control systems to meet projected emissions regulations during the period 2000 to 2010. APBF-DEC is conducting five separate projects involving light- and heavy-duty engine platforms. Four projects are focusing on the performance of emission control technologies for reducing criteria emissions using different fuels. This project is investigating the effects of lubricant formulation on engine-out emissions (Phase I) and the resulting impact on emission control systems (Phase II). This paper describes the statistical design and analysis methods used during Phase I of the lubricants project.
1971-02-01
Technical Paper
710197
W. H. Safranek, H. R. Miller, A. R. Cook
The cost of electroplating zinc die castings can be reduced by employing microcracked or microporous chromium in place of conventional chromium; the former is more effective in improving corrosion performance while conserving nickel. Exposure data are examined and specifications for nickel and chromium content are presented.
1964-01-01
Technical Paper
640092
D. N. Williams
Increased research devoted to the foundry arts has resulted in a greater understanding of the factors essential in producing high quality castings. One outgrowth of these studies has been the development of premium quality aluminum castings. The procedures used for the production of premium quality castings are reviewed, and the improvements in properties that result from adequate attention to these procedures are described.
1961-01-01
Technical Paper
610321
Mary Jane Oestmann, J. F. Kircher
1963-01-01
Technical Paper
630169
W. H. Safranek, H. R. Miller
After several alternative procedures were investigated for preparing chromium-plated zinc die castings for painting, one procedure proved best for contaminated chromium surfaces. This procedure included six steps: (1) alkaline spray cleaning, (2) electrolytic alkaline cleaning, (3) rinsing with high-purity water with a specific resistance of 500,000-700,000 ohm-cm, (4) immersing in chromic acid solution (0.05 oz/gal) at 150 F for 2 minutes, or treating cathodically in 0.7 oz/gal of sodium dichromate with a current density of 0.05 amp/sq ft for 30-60 sec, (5) rinsing with high-purity water, (6) forced-air drying with filtered air at 15 psi. Good adherence was obtained by following these procedures and painting with a single coat of acrylic or alkyd-resin paint. Other preparation procedures resulted in inferior paint adherence.
1949-01-01
Technical Paper
490090
H. A. PRAY
2000-10-03
Technical Paper
2000-01-2723
X. Sun, M. A. Khaleel, R. W. Davies, S.T. Gulati
An axisymmetric finite element model is generated to simulate the windshield glass damage propagation subjected to impact loading of a flying object. The windshield glass consists of two glass outer layers laminated by a thin poly-vinyl butyral (PVB) layer. The constitutive behavior of the glass layers is simulated using brittle damage mechanics model with linear damage evolution. The PVB layer is modeled with linear viscoelastic solid. The model is used to predict and examine through-thickness damage evolution patterns on different glass surfaces and cracking patterns for different windshield designs such as variations in thickness and curvatures.
2001-05-14
Technical Paper
2001-01-2068
Kevin Walkowicz, Denny Stephens, Kevin Stork
This paper summarizes the Next Generation Natural Gas Vehicle (NG-NGV) Program that is led by the U.S. Department Of Energy's (DOE's) Office of Heavy Vehicle Technologies (OHVT) through the National Renewable Energy Laboratory (NREL). The goal of this program is to develop and implement one Class 3-6 compressed natural gas (CNG) prototype vehicle and one Class 7-8 liquefied natural gas (LNG) prototype vehicle in the 2004 to 2007 timeframe. OHVT intends for these vehicles to have 0.5 g/bhp-hr or lower emissions of oxides of nitrogen (NOx) by 2004 and 0.2 g/bhp-hr or lower NOx by 2007. These vehicles will also have particulate matter (PM) emissions of 0.01 g/bhp-hr or lower by 2004. In addition to ambitious emissions goals, these vehicles will target life-cycle economics that are compatible with their conventionally fueled counterparts.
1990-04-01
Technical Paper
900975
C. H. Cundiff, O. L. Deel, Robert O'Sullivan
Abstract Chemical and physical properties of various plastics used for plastic abrasive applications are presented. All testing is done in compliance with MIL-P-85891 (AS), “Plastic Media for Removal of Organic Coatings”. Density and heavy density particle contamination are particularly important tests relative to aerospace applications.
1990-04-01
Technical Paper
900974
C. H. Cundiff, O. L. Deel, Robert O'Sullivan
Abstract Performance of various plastic abrasive materials is compared in a typical aerospace coatings removal application. Media aggressiveness towards substrates, stripping capabilities, effects of plastic breakdown, and plastic consumption are compared. Lower density plastics are shown to be more substrate protective than higher denisty plastics. Stripping rates are shown to be dependent both on plastic hardness and breakdown resistance of the plastic.
1990-04-01
Technical Paper
900956
C. H. Cundiff, O. L. Deel, Robert O'Sullivan
Abstract Optimization parameters designed to minimize residual stress and maximize coatings removal rates are presented. Stress saturation curves are presented and compared for the optimized blasting parameters using different plastic abrasive materials.
2010-02-05
Article
Government-funded research programs, large-scale computing, and nanotechnology are a few of the areas that experts believe will drive the deployment of new energy technologies.
2010-02-05
Article
Materials science and engineering will continue to play a major role in realizing new energy opportunities such as solar, wind, and biofuels, as well as making advances in energy storage.
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