118,772 research outputs found

    Stimulating curiosity to enhance learning

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    Curiosity is an aspect of intrinsic motivation that has great potential to enhance student learning. Theory and evidence describing curiosity are discussed, focusing on psychological and pedagogical literature relating to adult education. In particular, the concept of ‘information gaps’ as a source of academic curiosity is explored. In addition, the concept of curiosity in two disparate sample disciplines; second language learning and medical education are considered. The role of inquiry based learning approaches are also discussed as potential modes of stimulating student curiosity, as well as simple classroom techniques, which could be applied to almost any academic discipline and based on the theories should act to enhance student curiosity

    Gas lubricant compositions Patent

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    High temperature gas lubricant consisting of two fluoro-bromo-methane

    Metallic film diffusion for boundary lubrication Patent

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    Metallic film diffusion for boundary lubrication in aerospace engineerin

    Formation of Ti–Zr–Cu–Ni bulk metallic glasses

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    Formation of bulk metallic glass in quaternary Ti–Zr–Cu–Ni alloys by relatively slow cooling from the melt is reported. Thick strips of metallic glass were obtained by the method of metal mold casting. The glass forming ability of the quaternary alloys exceeds that of binary or ternary alloys containing the same elements due to the complexity of the system. The best glass forming alloys such as Ti34Zr11Cu47Ni8 can be cast to at least 4-mm-thick amorphous strips. The critical cooling rate for glass formation is of the order of 250 K/s or less, at least two orders of magnitude lower than that of the best ternary alloys. The glass transition, crystallization, and melting behavior of the alloys were studied by differential scanning calorimetry. The amorphous alloys exhibit a significant undercooled liquid region between the glass transition and first crystallization event. The glass forming ability of these alloys, as determined by the critical cooling rate, exceeds what is expected based on the reduced glass transition temperature. It is also found that the glass forming ability for alloys of similar reduced glass transition temperature can differ by two orders of magnitude as defined by critical cooling rates. The origins of the difference in glass forming ability of the alloys are discussed. It is found that when large composition redistribution accompanies crystallization, glass formation is enhanced. The excellent glass forming ability of alloys such as Ti34Zr11Cu47Ni8 is a result of simultaneously minimizing the nucleation rate of the competing crystalline phases. The ternary/quaternary Laves phase (MgZn2 type) shows the greatest ease of nucleation and plays a key role in determining the optimum compositions for glass formation

    A conceptual approach for noncontact calorimetry in space

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    A concept is developed and described which allows to measure the heat capacity and the effective thermal conductivity of stable and undercooled liquid metals and alloys in an electromagnetic levitation apparatus. We propose to use an ac pulse heating method which is used nowadays as a standard technique for precision measurement of low temperature heat capacities. The ideal process parameters including the drop diameter D, temperature T, and frequency of measurement ω can be optimized when the following relations hold for the external and internal relaxation time constants τ_1 and τ_2, respectively: ωτ_1≳10 and ωτ_2<0.1. Then heat capacity data can be obtained with an accuracy of better than 1% with D about 5 to 10 mm, T between 1200 and 1800 K and ω between 0.1 and 1 Hz for typical metals and alloys

    Evaluation of lubricants for ball bearings at high temperatures

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    Calcium fluoride-barium fluoride coating on ball bearing cages or as fillers in porous bearing cages lubricate bearings successfully for operations in air at temperatures of 1200 to 1500 degrees F

    Alloys for bearings Patent

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    Metal alloy bearing materials for space application

    Bearing alloys with hexagonal crystal structures provide improved friction and wear characteristics

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    Bearings of titanium, cobalt, and other hexagonal crystal alloys are used in vacuum and high temperature environments. These temperature-stabilized alloys have reduced friction and wear characteristics and therefore have potential use in aircraft seals, hydraulic equipment, and artificial human joints

    Lead oxide ceramic makes excellent high-temperature lubricant

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    A dry lubricant coating in ceramic form consisting of 95 percent lead monoxide and 5 percent silicon dioxide withstood a temperature of 1200 deg F, with a bearing operating at various atmospheric pressures. From this testing, there was no galling or metal transfer of the bearing

    TREATMENT OF HEMOPHILIA WITH HUMAN FACTORIX PRODUCED IN MAMIMARY TISSUE OF TRANSGENIC MAMMALS

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    Recombinant Factor IX characterized by a high percentage of active protein can be obtained in the milk of transgenic animals that incorporate chimeric DNA molecules according to the present invention. Transgenic animals of the present invention are produced by introducing into developing embryos DNA that encodes Factor IX, such that the foreign DNA is stably incorporated in the DNA of germ line cells of the mature animal. Particularly efficient expression was accomplished using a chimeric construct comprising a mammary gland specific promoter, Factor IX cDNA that lacked the complete or any portion of the 5\u27-untranslated and 3\u27-un-translated region, which is substituted with a 5- and 3\u27-end of the mouse whey acidic protein gene. In vitro cell cultures of cells explanted from the transgenic mammal of the invention and methods of producing Factor IX from such said culture and methods of treating hemophilia B are also described
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