A cyclonic eddy train and poleward heat transport in the Australian-Antarctic Basin

The Tenth Symposium on Polar Science/Ordinary sessions: [OM] Polar Meteorology and Glaciology, Thu. 5 Dec. / 2F Auditorium , National Institute of Polar Researc

Structure of Meridional Circulation in Southern Ocean captured by long term Mooring

The Tenth Symposium on Polar Science/Ordinary sessions: [OM] Polar Meteorology and Glaciology, Wed. 4 Dec. / Entrance Hall (1st floor) , National Institute of Polar Researc

Forgeability of AZ Series Magnesium Alloy produced by Twin Roll Casting

Plastic forming of magnesium alloy is hardly reported because of its low forgeability. The productions of magnesium alloy are mainly produced by casting. Typical wrought magnesium alloy is AZ31. Magnesium-aluminum alloy indicates maximum elongation when the composition includes 3% aluminum. When the magnesium alloy includes over 3% aluminum, its elongation slightly decreases. Therefore, AZ31 that include 3% aluminum and 1% zinc is generally used for plastic forming. The more increasing aluminum composition, the larger 0.2% proof stress becomes. However its forgeability is decreasing because of precipitation of β phase such as Mg17Al12. It is supposed that the β phase is refined by rapid cooling casting process such as twin roll casting. In this paper, the magnesium alloy thick sheet of AZ91, AZ121 and AZ131 for hot forging, that include 9%, 12% and 13% aluminum composition respectively, was produced by twin roll strip casting process. And the forgeability of high aluminum containing magnesium alloy was investigated by die forging. As a result, it was possible to forge their magnesium alloys

Properties of Antarctic Bottom Water observed by mooring system off Vincennes Bay

第3回極域科学シンポジウム/第35回極域気水圏シンポジウム 11月29日（木） 国立国語研究所 ２階多目的

Rapid and persistent freshening of Antarctic Bottom Water in the Australian-Antarctic Basin

第6回極域科学シンポジウム分野横断セッション：[IG] 全球環境変動を駆動する南大洋・南極氷床11月17日（火）　国立極地研究所 2階 大会議

南極底層水を起点とする熱塩循環・物質循環のダイナミクス

第6回極域科学シンポジウム分野横断セッション：[IG] 全球環境変動を駆動する南大洋・南極氷床11月17日（火）　国立極地研究所 2階 大会議

Evolution of structures and fabrics in the Barbados Accretionary Prism ; Insights from Leg 110 of the Ocean Drilling Program

The microstructures and crystal fabrics associated with the development of an amphibolite facies quartzo-feldspathic mylonitic shear zone (Torridon, NW Scotland) have been investigated using SEM electron channelling. Our results illustrate a variety of microstructures and fabrics which attest to a complex shear zone deformation history. Microstructural variation is particularly pronounced at low shear strains: significant intragranular deformation occurs via a domino-faulting style process, whilst mechanical incompatibilities between individual grains result in characteristic grain boundary deformation accommodation microstructures. A sudden reduction in grain size defines the transition to medium shear strains, but many of the boundaries inherited from the original and low shear strain regions can still be recognized and define distinctive bands oriented at low angles to the shear zone margin. Grains within these bands have somewhat steeper preferred dimensional orientations. These domains persist into the high shear strain mylonitic region, where they are oriented subparallel to the shear zone margin and consist of sub-20 μm grains. The microstructures suggest that the principal deformation mechanism was intracrystalline plasticity (with contributions from grain size reduction via dynamic recrystallization, grain boundary migration and grain boundary sliding). Crystal fabrics measured from the shear zone vary with position depending on the shear strain involved, and are consistent with the operation of several crystal slip systems (e.g. prism, basal, rhomb and acute rhomb planes) in a consistent direction (probably parallel to a and/or m). They also reveal the presence of Dauphine twinning and suggest that this may be a significant process in quartz deformation. A single crystal fabric evolution path linking the shear zone margin fabric with the mylonitic fabric was not observed. Rather, the mylonitic fabric reflects the instantaneous fabric which developed at a particular location for a particular shear strain and original parental grain orientation. The mature shear zone therefore consists of a series of deformed original grains stacked on top of each other in a manner which preserves original grain boundaries and intragranular features which develop during shear zone evolution. The stability of some microstructures to higher shear strains, the exploitation of others at lower shear strains, and a continuously evolving crystal fabric, mean that the strain gradient observed across many shear zones is unlikely to be equivalent to a time gradient