NASA Technical Reports Server (NTRS)
(592.609 recursos)
The NTRS is a valuable resource for students, educators, researchers, and the public for access to NASA's current and historical technical literature since it was first released in 1994. NTRS provides access to approximately 500K aerospace related citations, 90K full-text online documents, and 111K images and videos. NTRS numbers continues to grow over time as new scientific and technical information (STI) is created or funded by NASA. The type of information found in NTRS include: conference papers, images, journal articles, photos, meeting papers, movies, patents, research reports, and technical videos.
Mostrando recursos 1 - 20 de 513.494
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Mars' Oceanus Borealis, Ancient Glaciers, and the MEGAOUTFLO Hypothesis - Baker, V. R.; Strom, R. G.; Dohm, J. M.; Gulick, V. C.; Kargel, J. S.; Komatsu, G.; Ori, G. G.; Rice, J. W., Jr.
Recent results from Global Surveyor corroborate the hypothesis that episodes of outburst flooding produced ponded water and climate change on Mars. This hypothesis colligates diverse facts concerning the Martian landscape and its history into a unified genetic system.
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Synthesis and Characterization of Nanocomposite Analogs of Interstellar Amorphous Silicates - Al-Badri, Z.; Keller, L. P.; Grier, D. G.; McCarthy, G. J.; Chauhan, B. P. S.; Boudjouk, P.
Synthetic analog materials consisting of nanophase Fe metal in a silica glass matrix have been prepared. The infrared properties of the analog materials show remarkable similarities to amorphous interstellar silicates. Additional information is contained in the original extended abstract.
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A Henry's Law Test for Experimental Partitioning Studies of Iron Meteorites - Chabot, N. L.; Campbell, A. J.; Humayun, M.; Agee, C. B.
Low-level doped solid metal/liquid metal experiments analyzed by laser ablation ICP-MS allow Henry's Law to be tested. The results indicate Henry's Law is obeyed and the experimental partition coefficients can be applied to iron meteorites. Additional information is contained in the original extended abstract.
8.
Probable Carbonate Fossilization Processes Within Dead Sea Microbial Remains - Morris, P. A.; Wentworth, S. J.; Thomas-Keprta, K. L.; Allen, C. C.; McKay, D. S.
Microbial fossilization processes in the Dead Sea is primarily associated with the calcium cation. The putative fossilized microbes do not represent the reported living microbial population. Additional information is contained in the original extended abstract.
9.
Mariner 9 Photoclinometric Analysis of the South Polar Layered Deposits on Mars - Herkenhoff, K. E.; Bridges, N. T.
Photoclinometric analysis of Mariner 9 narrow-angle (approx. 80 m/pixel) images of the south polar layered deposits indicates that even relatively rough terrains in the images studied rarely include slopes greater than 10 degrees.
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The Possible Determination of Internal Isochrons for Iron Meteorites - Chen, J. H.; Papanastassiou, D. A.; Wasserburg, G. J.
Re-Os on metal and schreibersite in iron meteorites provides the potential for the determination of internal isochrons for irons. This is applied to Wallapai (IID) and other samples. Additional information is contained in the original extended abstract.
11.
Chicxulub High-Altitude Ballistic Ejecta from Central Belize - Pope, K. O.; Ocampo, A. C.
Chicxulub ejecta are found in central Belize, 475 km southeast of the impact crater center. These deposits are ballistic ejecta launched along high-altitude trajectories above the atmosphere and deposited as a discontinuous sheet on the terminal Cretaceous land surface.
12.
Topography and Aeolian Features: Dunes and Streaks Compared with Global and Meso Scale Wind Predictions - Greeley, R.; Rafkin, S. C. R.; Haberle, R. M.; Kuzmin, R. O.
Aeolian features have been compared with global and meso-scale models of the atmospheric circulation which predict near-surface winds as a function of variables such as martian season and location on the planet. Additional information is contained in the original extended abstract.
15.
Post-Impact Hydrothermal Activity at the Haughton Impact Structure, Devon Island, Nunavut, Canada - Osinski, G. R.; Spray, J. G.; Bunch, T. E.; Grieve, R. A. F.; Schutt, J. W.; Lee, P.
Evidence for impact-generated hydrothermal activity is reported from the Haughton crater, Canada. Two distinct settings have been found: (1) pipe structures with marcasite, pyrite and minor chalcopyrite; (2) cavity and fracture fillings with marcasite predominant.
16.
The Mars Surveyor Program: Planned Orbiter and Lander for 2001 - Saunders, R. S.
Replanning could affect the 2001 mission. The orbiter will arrive at Mars on Oct. 20, 2001, carrying the Gamma Ray Spectrometer (GRS) and the Thermal Emission Imaging System (THEMIS). The Lander is scheduled to land on Mars on January 22, 2002.
19.
Orbital Synthetic Aperture Radar (SAR) for Mars Post Sample Return Exploration - Thompson, T. W.; Plaut, J. J.; Arvidson, R. E.; Paillou, P.
A Mars orbital radar mission would use two frequencies to map the planet at 50 m resolution, penetrating 5-10 m. Some areas will be imaged at 5-m resolution. A 50-m resolution topographic map will be acquired, and surface changes detected.
20.
Evaluation of Forces on the Welding Probe of the Automated Retractable Pin-Tool (RPT) - Ding, R. J.
The NASA invention entitled 'The Hydraulic Controlled Auto-Adjustable Pin Tool for Friction Stir Welding' (US Patent 5,893,507), better known as the Retractable Pin-Tool (RPT), has been instrumented with a load-detecting device allowing the forces placed on the welding probe to be measured. As the welding probe is plunged into the material, the forces placed on the probe can now be characterized. Of particular interest are those forces experienced as the welding probe comes within close proximity to the back-up anvil. For a given material, it is believed that unique forces are generated relative to the distance between the welding probe...
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