Glass fibres of pure and erbium- or neodymium-doped yttria-alumina compositions
Article Abstract:
Containerless liquid-phase processing can be used to achieve deep undercooling of molten oxides to temperatures where the viscosity is sufficient for fibre-pulling operations. It was possible to pull glass fibres up to 0.5 m long at rates of 1 m s-1 to 1.5 m s-1 before crystallization of the melt stopped the process. The fibre-pulling behaviour seen for pure yttrium aluminium garnet and doped compositions may be the result of the greater sensitivity of undercooling behaviour in general for the pure composition.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1998
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Evidence against 'ultrahard' thermal turbulence at very high Rayleigh numbers
Article Abstract:
There are several theories that predict a limiting and universal turbulent regime, ultrahard turbulence, occurs at large Rayleigh numbers in a closed, rigid-walled cell. The ultrahard state is thought to support more efficient thermal transport than hard turbulence. However no evidence of a transition to an ultrahard state was found in experiments on Rayleigh-Benard convection in mercury at thigh effective Rayleigh numbers, suggesting that the limiting state is ordinary hard turbulence.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1999
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Bulk glasses and ultrahard nanoceramics based on alumina and rare-earth oxides
Article Abstract:
A process using alumina-rare-earth oxide systems (Al2O3-RE2O3) for preparing very-high-alumina glasses and nanoscale glass-ceramics is presented. The techniques used can be extended to form glasses and nanoceramics in other oxide systems that do not include a conventional glass-forming component.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 2004
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