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Aerogels are the least dense and most porous materials known to man, with potential applications from lightweight superinsulators to smart energy materials. To date their use has been seriously hampered by their synthesis methods, which are laborious and expensive. Taking inspiration from the life cycle of the damselfly, a novel ambient pressure-drying approach is demonstrated in which instead of employing low-surface-tension organic solvents to prevent pore collapse during drying, sodium bicarbonate solution is used to generate pore-supporting carbon dioxide in situ, significantly reducing energy, time, and cost in aerogel production. The generic applicability of this readily scalable new approach is demonstrated through the production of granules, monoliths, and layered solids with a number of precursor materials.

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Metallographic examination performed on a number of micropitted gears has revealed microstructural features similar to those reported in the literature in fatigued bearings, namely, dark etching regions and white etching bands. In addition, a new type of fatigueinduced microstructural constituent was observed close to the surface below asperities referred to as the plastic deformation region. Finally, it is shown that the initiation and propagation of cracks leading to the formation of micropits are related to the phase transformations mentioned previously.

No abstract