Browsing by Author "Komatsu, K"

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    Hydrates under pressure - new insights from sulfuric acid hydrates
    (Australian Institute of Physics, 2016-02-04) Maynard-Casely, HE; Hattori, T; Sano-Furukawa, A; Machida, S; Komatsu, K
    Hydrates are a rich and diverse class of materials that display a wide range of structures and properties – a feature that is only exaggerated when they are subjected to high-pressures. Consequently, these have implications on our understanding of many outer solar system bodies, where hydrates are amongst the dominant materials found there. For Europa and Ganymede, two moons under intense investigation from past and future space missions, their surfaces seen to be mostly water-ice and hydrates. Despite the apparent ‘simplicity’ of these materials, we still observe very complex geological formations on these moons – including subduction. Hence, we need to understand the transformations of candidate surface materials under a range of pressure/temperature conditions in order to accurately explain the formations on these icy surfaces. One hydrate candidate material for the surfaces of these moons are sulfuric acid hydrates, formed from radiolytic sulfur (from Io) reacting with the surface ice. Sulfuric acid hydrates have already been established to have a complex phase diagram with composition. We have now used the Mito cell at the PLANET instrument to undertake the first investigation of the high-pressure behaviour of the water rich sulfuric acid hydrates. Compressing at 100 K and 180 K we see that the hemitriskaidekahydrate becomes the stable water-rich hydrate and observe some interesting relaxation behaviour in this material at pressure, which could have significant consequences for the interiors of Ganymede.
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    Three impossible things before lunch - the task of a sample environment specialist
    (IOS Press, 2017-11-16) Booth, N; Davidson, G; Imperia, P; Lee, S; Stuart, BH; Thomas, PS; Komatsu, K; Yamane, R; Prescott, SW; Maynard-Casely, HE; Nelson, A; Rule, KC
    In the course of their day, sample environment professionals can be confronted by numerous technical challenges applicable to a range of scientific questions. This paper presents three successful outcomes from user-posed sample environment challenges for in situ neutron scattering experiments undertaken at the Australian Centre for Neutron Scattering (formerly the Bragg Institute). The sample environments presented here have nothing in common other than their novelty. They may not be the best solution but have been constrained by time, resources and ability. The questions the users posed were: Can we mount a cylinder in cylinder (CIC) rheometer, more regularly used on a small angle scattering instrument, on a diffraction instrument and obtain usable data? Can we supply high-voltage (up to 10 kV) across a sample within the Paris–Edinburgh press while mounted on a powder diffraction instrument? And finally can a Lakeshore 340 and an in-house built liquid conductivity cell do the job of a commercial liquid conductivity meter? This paper presents the engineering and equipment solutions that were used to answer these questions, and in each case the scientific users left with useful, intriguing and, hopefully, publishable data. © 2017 IOS Press