2,061 research outputs found

    Oxide deformation and fiber reinforcement in a tungsten metal oxide composite

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    Oxide deformation and fiber reinforcement in tungsten-urania and tungsten-zirconia elongated into fibers by hot extrusio

    Extrusion of small-diameter, thin-wall tungsten tubing

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    Small-diameter, thin-wall seamless tubing of tungsten has been fabricated in lengths of up to 10 feet by hot extrusion over a floating mandrel. Extrusion of 0.50-inch-diameter tubing over 0.4-inch-diameter mandrels was accomplished at temperatures ranging from 3000 degrees to 4000 degrees F

    Tantalum modified ferritic iron base alloys

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    Strong ferritic alloys of the Fe-CR-Al type containing 0.4% to 2% tantalum were developed. These alloys have improved fabricability without sacrificing high temperature strength and oxidation resistance in the 800 C (1475 F) to 1040 C (1900 F) range

    Advanced materials research for long-haul aircraft turbine engines

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    The status of research efforts to apply low to intermediate temperature composite materials and advanced high temperature materials to engine components is reviewed. Emerging materials technologies and their potential benefits to aircraft gas turbines were emphasized. The problems were identified, and the general state of the technology for near term use was assessed

    Design and evaluation of experimental ceramic automobile thermal reactors

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    The results obtained in an exploratory evaluation of ceramics for automobile thermal reactors are summarized. Candidate ceramic materials were evaluated in several reactor designs by using both engine-dynamometer and vehicle road tests. Silicon carbide contained in a corrugated-metal support structure exhibited the best performance, lasting 1100 hr in engine-dynamometer tests and more than 38,600 km (24000 miles) in vehicle road tests. Although reactors containing glass-ceramic components did not perform as well as those containing silicon carbide, the glass-ceramics still offer good potential for reactor use with improved reactor designs

    Evaluation of alloys and coatings for use in automobile thermal reactors

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    Several candidate alloys and coatings were evaluated for use in automobile thermal reactors. Full-size reactors of the candidate materials were evaluated in cyclic engine dynamometer tests with a peak temperature of 1040 C (1900 F). Two developmental ferritic-iron alloys, GE-1541 and NASA-18T, exhibited the best overall performance by lasting at least 60 percent of the life of test engine. Four of the alloys evaluated warrant consideration for reactor use. They are GE-1541, Armco 18 SR, NASA-18T, and Inconel 601. None of the commercial coating substrate combinations evaluated warrant consideration for reactor use

    Development of dispersion-strengthened Ni-Cr-ThOz alloys for the space shuttle thermal protection system

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    Manufacturing processes were developed for TD-NiCr providing small sheet (45 x 90 cm), and larger sheet (60 x 150 cm) and foil. The alternate alloy, DS-NiCr, was produced by pack-chromizing Ni-ThO2 sheet. Formability criteria are being established for basic sheet forming processes, which are brake forming, corrugation forming, joggling, dimpling, and beading. Resistance spot welding (fusion and solid state), resistance seam welding, solid state diffusion welding, and brazing are included in the joining programs. Major emphasis is centered on an Al-modified Ni-Cr-ThO2 alloy development. These alloys, containing 3 to 5% Al, form the protective Al2O3 scale. This enhances oxidation resistance under reentry conditions. Both TD-NiCrAl and DS-NiCrAl alloys are included. A tentative composition of Ni-16Cr-3.5Al-2ThO2 was selected based on oxidation resistance and fabricability

    Opportunities for ceramics in the ERDA/NASA continuous combustion propulsion systems program

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    An overview on engine development projects for potential use of ceramics is reported. A major ceramics materials technology effort is described to meet anticipated engine system requirements in terms of the automotive application, some of the more pressing technology needs, and some indications of how to conduct this technology program with industry-engine development projects focus on both gas turbine and Stirling engines

    Fostering Independent Learners of Information Systems in the 21st Century Through Integrated Educational Technologies

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    The topic of this panel session is the management and delivery of course content through the integration of new instructional technologies to facilitate independent student learning in technical courses. The two lead panelists will provide examples and explanations of newly restructured information systems courses using a range of instructional technologies, including an online course management system, student response system, online video tutorial approach, classroom information systems synchronization tools, smart classroom technologies, and online student collaboration tools. These courses have been developed to foster a move away from the traditional classroom lecture “teaching centric” paradigm to an independent “learner centric” paradigm. This classroom methodology was developed as one result of the work completed for an NSF-funded project, Expanding Pathways for Educational Development and Information Technology Experiences (ExPEDITE). A focus of this classroom methodology is presenting technology-based course material to students with little to no technical background. These students often perceive technology-related classes as extremely difficult and many times overwhelming. The proposed methodology uses the various instructional technologies to slowly build the learner’s background through a gradual, repetitive learning process where the learner becomes more independent with each classroom activity

    Effect of forward motion on engine noise

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    Methods used to determine a procedure for correcting static engine data for the effects of forward motion are described. Data were analyzed from airplane flyover and static-engine tests with a JT8D-109 low-bypass-ratio turbofan engine installed on a DC-9-30, with a CF6-6D high-bypass-ratio turbofan engine installed on a DC-10-10, and with a JT9D-59A high-bypass-ratio turbofan engine installed on a DC-10-40. The observed differences between the static and the flyover data bases are discussed in terms of noise generation, convective amplification, atmospheric propagation, and engine installation. The results indicate that each noise source must be adjusted separately for forward-motion and installation effects and then projected to flight conditions as a function of source-path angle, directivity angle, and acoustic range relative to the microphones on the ground
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