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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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George Diller, NASA Public Affairs, introduces Bill Gerstenmaier, Deputy Manager of the ISS Program, Dave King, NASA Director of Shuttle Processing, and Judy Konecky, Staff Meteorologist, in this STS-105 press conference. An overview is given of the success of the Expedition 2 crew, the expectations of the Expedition 3 crew, the launch countdown status, and the weather forecast for the Shuttle launch. They then answer questions from the press.
George Diller, NASA Public Affairs, introduces Jim Halsell, Shuttle Program Launch Integration Manager, Dave King, NASA Director of Shuttle Processing, Michael Hawes, Deputy Associate Administrator for ISS, and John Weems, Launch Weather Officer, in this STS-104 press conference. An overview is given of the launch and mission activities, International Space Station activities during the mission, and the weather forecast for the launch. The men then answer questions from the press.
Joel Wells, NASA Public Affairs, introduces the STS-104 crew, Commander Steven Lindsey, Pilot Charles Hobaugh, and Mission Specialists Mike Gernhardt, Jim Reilly, and Janet Kavandi, in this post-landing press conference. Commander Lindsey makes a brief statement about the mission and each crewmember's role in the activities. The crew then answers questions from the press.
A continuation of 'Apollo 11 Facts: Post Flight Press Conference, Part 1 of 2' (internal ID 2001181405), this video shows Apollo 11 Commander Neil Armstrong, Lunar Module Pilot Edwin Aldrin, Jr., and Command Module Pilot Michael Collins during a post flight press conference, where they describe their experiences on the mission. The astronauts then answer questions from the audience.
Flight Director Gene Krantz gives an overview of the Apollo 13 mission as corrections are made in the power down checklist, passive thermal control, and orbital burns after the spacecraft runs into problems. He then answers questions from the press with the help of Tony England, Bill Peters, and Dick Thorson. Footage then shows newspaper headlines 'We're Not Concerned' and 'Getting Ready to Land' as people watch televisions to see if the astronauts landed safely. The press conference section of this video has sound, the headlines section does not.
On July 17, 2006 Dean Acosta (NASA Press Secretary), Mike Griffin (Administrator), Bill Gerstenmaier (Associate Administrator of Space Operations), and Mike Leinbach (NASA Launch Director) expressed how proud they were to be a part of the STS-121/ Discovery team. They also explained how flawlessly the mission performed and how it was the best mission ever flown. They proceeded to answer numerous questions from the press.
The briefing begins with Dean Acousta (NASA Press Secretary) introducing Michael Griffin (NASA Administrator), Bill Gerstenmaier (Associate Administrator for Space Operations) Wayne Hale (Space Shuttle Program Manager), John Shannon (Chairman, Mission Management Team, JSC), and Mike Leinbach (NASA Launch Director). The teams effort and dedication paid off in the form of a perfect launch and the weather cooperated. The Mission Management Team no problems during inspection. Debris assessment at 2 min. 47 sec. and 4 min. 50 sec. will be discussed when that information becomes available.The floor was then open for questions from the press.
Steve Stitch, STS-121 Entry Flight Director, and Wayne Hale, Space Shuttle Program is shown in this post landing press conference. Steve Stitch begins with discussing the following topics: 1) Weather at Kennedy Space Center; 2) Gap filler protrusion; 3) De-orbit burn; 4) Space Shuttle Landing; 5) Global Position Satellite System (GPSS) performance; and 6) Post-landing rain showers. Wayne Hale discusses external tank observations at launch and the goals that were obtained by this flight, which are to deliver 4000 pounds of scientific equipment, increase the crew members to three on the International Space Station (ISS), and repair the ISS. Questions from the press on lessons learned from the Auxiliary Power Unit (APU) leak, and flight readiness reviews are addressed.
Aiming to develop alloys with better properties for orthopedic applications, the focus of the present research was to evaluate the effect of Mo at.% content on structural, mechanical, and tribological properties of hot isostatically pressed Ti-xMo (x = 4, 8, 12, 15, and 20 at.%) alloys. The structural evolution, mechanical properties, and tribological behavior of the nanostructured Ti-xMo alloys were evaluated using x-ray diffraction, scanning electron microscope, and ball-on-disk tribometer. Wear tests were conducted under different applied loads of 2, 8, and 16 N. Experimental results indicated that the structural evolution and morphological changes of the milled alloys were sensitive to their molybdenum (Mo) content. The morphological characterization showed that the crystallite size and the particle size decreased with increasing Mo content (at.%) reaching the lowest values of 27 and 26 nm in the case of Ti-15Mo and Ti-20Mo, respectively. On the other hand, the coefficient of friction and wear rates were found to be decreasing with increasing Mo content.
This article presents an assessment of the residual stress field on U10Mo alloy based monolithic fuel plates and their elasto-plastic response to the thermo-mechanical fabrication process. Monolithic plate-type fuel for research and test reactors is a new fuel form proposed and developed by Idaho National Laboratory (INL) to accomplish higher uranium densities in the reactor core and allow multi-fold reduction of fuel enrichment. Identification of the 3D residual field is critical for benchmarking the new design and understanding the overall performance of the new plate-type fuels. To define fuel-cladding stress-strain characteristics, a new thermo-mechanical finite element model was developed. Material properties at high temperatures and material plasticity were considered carefully to improve the accuracy as the Hot Pressing temperature reaches the melting temperature of the cladding material. By using elasto-thermo-plastic material models, it was determined that the cladding material (AL6061-TO) is exposed to tensile stress field and exceeds its proportional limits, while the fuel foil (U10Mo) is under compression and remains below its yield limit. It was shown that the residual stresses would govern the overall behavior of the plates, and therefore, should not be neglected. In particular, the simulations have revealed the existence of stress gradients at the fuel/cladding interface, thus emphasizing the necessity of excellent bonding quality at the bond region for mechanical endurance.
A highly efficient press is developed for extruding oil from low- and high-quality crops.
Powder metallurgy hot isostatic pressing (PM-HIP) is a mature advanced manufacturing technology, which can consolidate metallic powder under high temperature and pressure to generate near-net shape components. This process can lower production costs and reduce component lead times for nuclear reactor construction and can be readily deployed in the near term for microreactor components because of their smaller size. The purpose of this work is to continue the evaluation of elevated-temperature cyclic material properties for PM-HIP 316H stainless steel. Prior scoping results have shown that the commercially procured PM-HIP stainless-steel materials have reduced creep-fatigue performance compared to wrought 316 stainless steels. To better understand how PM-HIP processed material properties compare to traditional manufacturing methods, additional billets of PM-HIP 316H stainless steel were procured and tested. This testing is necessary to understand how elevated-temperature properties are influenced by the PM-HIP process and what data are needed for incorporating PM HIP 316H into the American Society of Mechanical Engineers Boiler Pressure Vessel Code, Section III, Division 5 for high temperature reactor construction. Specifically, an additional PM-HIP 316H stainless steel billet with lower oxygen and nitrogen concentrations was fabricated by the Nuclear Advanced Manufacturing Research Centre of the United Kingdom and tested to understand if elevated-temperature cyclic properties can be improved. The creep-fatigue resistance of the material from this new billet did not show appreciable improvement compared to prior testing.
The interaction between Mg, Si, and Al 2 O 3 during hot isostatic pressing diffusion bonding of aluminum alloy 6061 (AA6061) plates was investigated through thermodynamic calculations and experimental microstructural characterization. Thermodynamic calculations as functions of temperature, pressure, and composition revealed that the interaction among Mg, Si, and Al 2 O 3 yields Mg 2 Si and either MgO + Al or MgAl 2 O 4 + Al, facilitating the reduction of Al 2 O 3 and allowing Al/Al metallic bonds to form. Total pressure variation had a negligible influence on the oxygen partial pressure, and consequently, the reaction product formation. Oxygen partial pressure variation as a function of temperature and initial amount of Al 2 O 3 determined the formation of either MgO or MgAl 2 O 4 . Experimental Hot Isostatic Pressure (HIP) bonding at 723 K and 833 K under a constant pressure of 1017 atm documented the cooling rate-dependent formation of β–Mg 2 Si precipitates. High-resolution transmission electron microscopy imaging and selected area electron diffraction patterns verified the formation of β–Mg 2 Si and MgO at the interface but did not detect MgAl 2 O 4 . In conclusion, findings from this study clarify the role of thermochemical interactions in oxide disruption and bonding mechanisms during HIP diffusion bonding of AA6061 and provide guidance for optimizing joining processes for monolithic nuclear fuel assemblies.
Equal channel angular pressing (ECAP) is an important severe plastic deformation process to produce ultrafine grained microstructures in metals and alloys. Magnesium and its alloys generally possess poor workability at temperatures below 250 °C. This investigation examines the influence of different passes and processing routes of ECAP on improving the workability of Mg alloy AZ31B. ECAP was carried out for three passes using a die of angle 120° using processing routes Bc and C. The operating temperature was 523 K for the first pass and 423 K for the subsequent two passes. The resultant microstructure and mechanical properties were determined. Workability of the alloy at 423 K (150 °C) was determined using upsetting experiments on cylindrical specimens machined from the annealed and ECAPed samples. Workability limit diagrams have been constructed for the various processed conditions. The workability data generated were also analyzed using five different workability criteria (also referred to as ductile fracture models) and the material constants for these five models were evaluated. Specimens processed by two passes through route C (pass 2C) exhibits better workability compared to other passes since the workability limit line after this pass shows maximum safe working area and lies above the other workability lines. Among the five different workability criteria investigated, the Freudenthal workability criterion is more suitable for prediction of failure in this alloy.
AA7075 matrix composite was obtained by mechanical alloying using ZrO{sub 2} particles as reinforcement. After that, the powders were cold-compacted into an aluminum tube and consolidated by equal channel angular pressing at 220 °C. The temperature influence was analyzed, and it was found by scanning electron microscopy that this route gave the minimum pore percentage. Besides, it was noticeable that the hardness was wide superior in comparison with the AA 7075 aged bulk alloy. In addition, there was no evidence of any chemical reaction between ZrO{sub 2} and alloying elements at the temperature employed. On the other hand, it was numerically and experimentally demonstrated that the more strained regions exhibited a higher relative density values.
Magnetic properties and microstructure of Nd-Fe-B sintered magnets fabricated by hot isostatic pressing (HIP) were studied. For comparison, magnets were also fabricated by vacuum sintering. The density reached 7.58 g/cm{sup 3} for the magnets HIP-sintered at 1123 K. The density of the magnets vacuum-sintered at 1123 K was much lower, which is of about 6.92 g/cm{sup 3}. While the density of magnets vacuum-sintered at 1318 K was the same as the HIP-sintered magnets, the sintering temperature was significantly decreased to 1123 K. In addition, the average grain size decreased from 9 to 6 μm, which has enhanced coercivity. Therefore, the coercivity increased from 1067.7 to 1238.5 kA/m, which is 16% higher than the vacuum-sintered magnets. HIP is a promising method to obtain high density and high coercivity Nd-Fe-B sintered magnets.
In the present study, a homogeneous ultrafine grain structure composite consisting of metallic glass particles reinforcements was developed by equal-channel angular pressing (ECAP) process. The microstructure of composite was characterized using x-ray diffraction (XRD), transmission electron microscopy (TEM) and electron backscatter diffraction (EBSD) techniques. The uniaxial compression test was used to determine the mechanical properties. The mechanisms of grain refinement during ECAP process were discussed based on the microstructural evolutions. A composite was successfully produced after four passes of ECAP, having an average grain size of 610 nm and compressive yield strength of 242 MPa. Also, the yield strength of composite after each pass was quantitatively estimated by considering all the effective strengthening mechanism. The findings showed that the dislocations strengthening mechanism with contribution of more than 50% plays a major role in strengthening the composite. There was a negligible gap between the experimental and theoretical values of yield strength for all ECAP pass numbers.
Nearly fully dense 50 vol.% SiCp/6061Al composites were fabricated via hot pressing (HPing) at temperatures ranging from 610 to 650 °C, with the axial load and holding time fixed as 25 MPa and 120 min, respectively. The interfacial reactions, microstructures, and properties of the SiCp/Al alloy were studied. The interface reaction between SiCp and the Al alloy was suppressed at annealing temperatures of 620 °C and below; however, the reaction intensified as the annealing temperature increased, producing Al{sub 4}C{sub 3}, Si, and Mg{sub 2}Si. With an increase in HPing temperature from 610 to 630 °C, the 6061Al alloy melted and gradually filled the pores in the SiC particles under the applied load. The density, bending strength, and thermal conductivity (TC) of the composites increased, whereas the coefficient of thermal expansion (CTE) of the composites decreased. With an increase in HPing temperature increased from 630 to 650 °C, the 6061Al alloy melt leaked through the sintered bodies, resulting in the microstructural degradation and property reduction of the composites. The 50 vol.% SiCp/6061Al composites fabricated by HPing at 630 °C exhibited optimal comprehensive properties [bending strength, 332.4 MPa; TC, 186.3 W(m K){sup −1}; and CTE, 7.9 × 10{sup −6}/°C (20-100 °C)], which were attributed to the highest relative density and the best SiCp/Al interfacial structure of the composites.