Measuring the dihedral angle of water at a grain boundary in ice by an optical diffraction method
Abstract Optical measurements have been made on the water lenses which form under pressure at grain boundaries in polycrystalline ice. Monochromatic light from a point source is focused by the lenses but, because the lenses are microscopic in size, the image is blurred by diffraction. The diffractio...
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Language: | English |
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Cambridge University Press (CUP)
1991
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Online Access: | http://dx.doi.org/10.1017/s0022143000042854 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000042854 |
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crcambridgeupr:10.1017/s0022143000042854 2024-03-03T08:46:05+00:00 Measuring the dihedral angle of water at a grain boundary in ice by an optical diffraction method Walford, M.E.R. Nye, J.F. 1991 http://dx.doi.org/10.1017/s0022143000042854 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000042854 en eng Cambridge University Press (CUP) Journal of Glaciology volume 37, issue 125, page 107-112 ISSN 0022-1430 1727-5652 Earth-Surface Processes journal-article 1991 crcambridgeupr https://doi.org/10.1017/s0022143000042854 2024-02-08T08:36:10Z Abstract Optical measurements have been made on the water lenses which form under pressure at grain boundaries in polycrystalline ice. Monochromatic light from a point source is focused by the lenses but, because the lenses are microscopic in size, the image is blurred by diffraction. The diffraction pattern observed under a microscope has been compared with the computed diffraction pattern to deduce the angle 2 θ at the rim of each lens. This is the dihedral angle for water at a grain boundary in ice, and gives the ratio of the grain-boundary energy to that of an ice-water interface. The most sensitive measurements are those made on the rings of the virtual diffraction pattern formed on the object side of the lens. They give θ = 12.5 ± 0.5° for the grain boundary under observation, which is 26% lower than the previous value for θ found by ignoring diffraction. Article in Journal/Newspaper Journal of Glaciology Cambridge University Press Journal of Glaciology 37 125 107 112 |
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Open Polar |
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Cambridge University Press |
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crcambridgeupr |
language |
English |
topic |
Earth-Surface Processes |
spellingShingle |
Earth-Surface Processes Walford, M.E.R. Nye, J.F. Measuring the dihedral angle of water at a grain boundary in ice by an optical diffraction method |
topic_facet |
Earth-Surface Processes |
description |
Abstract Optical measurements have been made on the water lenses which form under pressure at grain boundaries in polycrystalline ice. Monochromatic light from a point source is focused by the lenses but, because the lenses are microscopic in size, the image is blurred by diffraction. The diffraction pattern observed under a microscope has been compared with the computed diffraction pattern to deduce the angle 2 θ at the rim of each lens. This is the dihedral angle for water at a grain boundary in ice, and gives the ratio of the grain-boundary energy to that of an ice-water interface. The most sensitive measurements are those made on the rings of the virtual diffraction pattern formed on the object side of the lens. They give θ = 12.5 ± 0.5° for the grain boundary under observation, which is 26% lower than the previous value for θ found by ignoring diffraction. |
format |
Article in Journal/Newspaper |
author |
Walford, M.E.R. Nye, J.F. |
author_facet |
Walford, M.E.R. Nye, J.F. |
author_sort |
Walford, M.E.R. |
title |
Measuring the dihedral angle of water at a grain boundary in ice by an optical diffraction method |
title_short |
Measuring the dihedral angle of water at a grain boundary in ice by an optical diffraction method |
title_full |
Measuring the dihedral angle of water at a grain boundary in ice by an optical diffraction method |
title_fullStr |
Measuring the dihedral angle of water at a grain boundary in ice by an optical diffraction method |
title_full_unstemmed |
Measuring the dihedral angle of water at a grain boundary in ice by an optical diffraction method |
title_sort |
measuring the dihedral angle of water at a grain boundary in ice by an optical diffraction method |
publisher |
Cambridge University Press (CUP) |
publishDate |
1991 |
url |
http://dx.doi.org/10.1017/s0022143000042854 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000042854 |
genre |
Journal of Glaciology |
genre_facet |
Journal of Glaciology |
op_source |
Journal of Glaciology volume 37, issue 125, page 107-112 ISSN 0022-1430 1727-5652 |
op_doi |
https://doi.org/10.1017/s0022143000042854 |
container_title |
Journal of Glaciology |
container_volume |
37 |
container_issue |
125 |
container_start_page |
107 |
op_container_end_page |
112 |
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1792501951247679488 |