75,429 research outputs found

    Emerging technologies as cognitive tools for authentic learning

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    Employing emerging technologies in learning is becoming increasingly important as a means to support the development of digital media literacy. Using a theoretical framework of authentic learning and technology as cognitive tools, this paper examined student responses to the infusion of emerging technologies in a large first year teacher education unit over two full iterations, using a design-based research approach. This paper describes the pedagogical context of the intervention, the methodology used, and it presents an analysis of themes emerging from the data relating to the use of emerging technologies

    Hollow rolling element bearings

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    A low mass rolling element with a lightweight core and hollow center was developed for use in bearings. The core is plated so as to provide a hard surface and increase the life and reliability of the high speed ball bearings

    Space technology's potential for industry

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    Space technology transfer to civilian applicatio

    Large-bore tapered-roller bearing performance and endurance to 2.4 million DN

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    The operating characteristics and experimental life estimates for 120.65 mm bore tapered roller bearings of two designs under combined radial and thrust loads were determined. A modified standard bearing design was tested at speeds up to 15,000 rpm. A computer optimized, high speed design was tested at speeds up to 20,000 rpm. Both designs were tested at a combined load of 26,700 N (6000 lb) radial load and and 53,400 N (12,000 lb) thrust load. Advanced helicopter transmissions which require the higher-speed capability of tapered-roller bearings also require higher temperature capability (ref. 2). Thus, materials with temperature capabilities higher than the conventional carburizing steels are required

    Strainer fits inside flared-tube fittings

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    Cylindrical wire-mesh strainer which fits inside flare-tube fittings is readily installed and easily replaced. It has a collar that seats on the tapered shoulder of the male fitting

    Mechanical properties of plastics predetermined by empirical method

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    To predetermine the mechanical properties of rigid plastics as a function of plasticizer content and composition, a set of equations has been empirically derived. These relate strain rate, yield stress, temperature, and weight fraction of the plasticizer

    Metallo-Organic Decomposition (MOD) film development

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    The processing techniques and problems encountered in formulating metallo-organic decomposition (MOD) films used in contracting structures for thin solar cells are described. The use of thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) techniques performed at Jet Propulsion Laboratory (JPL) in understanding the decomposition reactions lead to improvements in process procedures. The characteristics of the available MOD films were described in detail

    High performance mixed bisimide resins and composites based thereon

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    Mixtures of bismaleimide/biscitraconirnide resins produces materials which have better handling, processing or mechanical and thermal properties, particularly in graphite composites, than materials made with the individual resins. The mechanical strength of cured graphite composites prepared from a 1:1 copolymer of such bisimide resins is excellent at both ambient and elevated temperatures. The copolymer mixture provides improved composites which are lighter than metals and replace metals in many aerospace applications
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