Compression behaviors of distorted rutile-type hydrous phases, MOOH (M = Ga, In, Cr) and CrOOD

Sano, Asami; Yagi, Takehiko*; Okada, Taku*; Goto, Hirotada*; Kikegawa, Takumi*

Physics and Chemistry of Minerals, 39(5), p.375 - 383, 2012/05

https://doi.org/10.1007/s00269-012-0487-y

X-ray diffraction measurements of distorted rutile-type oxyhydroxides -GaOOH, InOOH, -CrOOH, and -CrOOD were taken at a maximum pressure of up to 35 GPa under quasi-hydrostatic conditions, at ambient temperature. Anomalies in the evolution of the relative lattice constants and the axial ratios of -GaOOH, InOOH, and -CrOOD suggest anisotropic stiffening along the a- and/or b-axes where the hydrogen bond is formed. The changes were observed at 15 GPa in -GaOOH and InOOH and at 4 GPa in -CrOOD. The pressures were higher in oxyhydroxides that have longer O...O distances of the hydrogen bond at ambient pressure. In contrast, such stiffening behavior was not observed in CrOOH, which has a significant short O...O distance and strong hydrogen bond. The stiffening behaviors observed in the present study can be attributed to the symmetrization of the hydrogen bonds in oxyhydroxides, as was previously found in -AlOOH(D).

Azimuthal correlations of electrons from heavy-flavor decay with hadrons in and Au+Au collisions at = 200 GeV

Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Aramaki, Y.*; et al.

Physical Review C, 83(4), p.044912_1 - 044912_16, 2011/04

https://doi.org/10.1103/PhysRevC.83.044912

Measurements of electrons from the decay of open-heavy-flavor mesons have shown that the yields are suppressed in Au+Au collisions compared to expectations from binary-scaled collisions. Here we extend these studies to two particle correlations where one particle is an electron from the decay of a heavy flavor meson and the other is a charged hadron from either the decay of the heavy meson or from jet fragmentation. These measurements provide more detailed information about the interaction between heavy quarks and the quark-gluon matter. We find the away-side-jet shape and yield to be modified in Au+Au collisions compared to collisions.

Determination of low-pressure crystalline-liquid phase boundary of SnI

Fuchizaki, Kazuhiro*; Fujii, Yasuhiko*; Oishi, Yasuo*; Omura, Ayako*; Hamaya, Nozomu*; Katayama, Yoshinori; Okada, Taku

Journal of Chemical Physics, 120(23), p.11196 - 11199, 2004/06

https://doi.org/10.1063/1.1751397

The location of the liquidus in the low-pressure crystalline phase of SnI was determined utilizing X-ray diffraction measurements under pressures up to approximately GPa. The liquidus is not well fitted to a monotonically increasing curve such as Simon's equation, but breaks near GPa and then becomes almost flat. The results are compared to those from molecular dynamics simulations. Ways to improve the model potential adopted in the simulations are discussed.

X-ray diffraction of graphite-diamond transformation using various catalysts under high pressures and high temperatures

Utsumi, Wataru; Okada, Taku; Taniguchi, Takashi*; Funakoshi, Kenichi*; Kikegawa, Takumi*; Hamaya, Nozomu; Shimomura, Osamu

Journal of Physics; Condensed Matter, 16(14), p.S1017 - S1026, 2004/04

https://doi.org/10.1088/0953-8984/16/14/011

The graphite-diamond transformation was investigated using in-situ time-resolved X-ray diffraction experiments with a MgO dissolved aqueous fluid as the diamond forming catalyst under conditions of 6.6-8.8 GPa and 1400-1835C. Experiments were conducted using a 180-ton DIA-type cubic-anvil apparatus installed on the beamline BL14B1 at SPring-8, a third-generation synchrotron radiation facility in Japan. By analyzing the kinetic data using the JMAK rate equation, it was clarified that altering the pressure-temperature conditions drastically changes the nucleation and growth process of diamond.

Nucleation and growth in bulk metallic glass under high pressure investigated using X-ray diffraction

Wang, W. H.*; Wen, P.*; Zhao, D. Q.*; Pan, M. X.*; Okada, Taku; Utsumi, Wataru

Applied Physics Letters, 83(25), p.5202 - 5204, 2003/12

https://doi.org/10.1063/1.1636517

no abstracts in English

Effect of pressure on nucleation and growth in the ZrTiCuNiBe bulk glass forming alloy investigated using in situ X-ray diffraction

Wang, W. H.*; Okada, Taku; Wen, P.*; Wang, X. L.*; Pan, M. X.*; Zhao, D. Q.*; Utsumi, Wataru

Physical Review B, 68(18), p.184105_1 - 184105_6, 2003/11

https://doi.org/10.1103/PhysRevB.68.184105

no abstracts in English

X-ray observations of the diamond formation process in the C-HO-MgO system

Okada, Taku; Utsumi, Wataru; Shimomura, Osamu

Journal of Physics; Condensed Matter, 14(44), p.11331 - 11335, 2002/11

https://doi.org/10.1088/0953-8984/14/44/477

In order to clarify the mechanism of diamond formation in the Earth's mantle, we studied the diamond formation in the HO-fluid by in situ X-ray observation with the simple C-HO-MgO system. The results suggest that the solubility of MgO component increases greatly as a function of pressure. However, the generation of fluid is not a sufficient condition for diamond formation, because the carbon quantity in fluid is not increased drastically until just before the diamond formation temperature. This is the first report of the kinetics study in fluid using synchrotron radiation.

In situ X-ray observations of the decomposition of brucite and the graphite-diamond conversion in aqueous fluid at high pressure and temperature

Okada, Taku; Utsumi, Wataru; Kaneko, Hiroshi*; Yamakata, Masaaki*; Shimomura, Osamu

Physics and Chemistry of Minerals, 29(7), p.439 - 445, 2002/08

https://doi.org/10.1007/s00269-002-0254-6

An experimental technique to make real-time observations at high pressure and temperature of the diamond forming process in candidate material of mantle fluids as a catalyst has been established for the first time. In situ X-ray diffraction experiments using synchrotron radiation have been performed upon a mixture of brucite (Mg(OH)) and graphite as starting material. Brucite decomposes into periclase (MgO) and HO at 3.6 GPa and 1050C while no periclase is formed after the decomposition of brucite at 6.2 GPa and 1150C, indicating that the solubility of the MgO component in HO greatly increases with increasing pressure. The conversion of graphite to diamond in aqueous fluid has been observed at 7.7 GPa and 1835C. Time-dependent X-ray diffraction profiles for this transformation have been successfully obtained.

The Effect of temperature, pressure, and sulfur content on viscosity of the Fe-FeS melt

Terasaki, Hidenori*; Kato, Takumi*; Urakawa, Satoru*; Funakoshi, Kenichi*; Suzuki, Akio*; Okada, Taku; Maeda, Makoto*; Sato, Jin*; Kubo, Tomoaki*; Kasai, Shizu*

Earth and Planetary Science Letters, 190(1-2), p.93 - 101, 2001/07

https://doi.org/10.1016/S0012-821X(01)00374-0

The Fe-FeS melt is thought to be the major candidate of the outer core material. Its viscosity is one of the most important physical properties to study the dynamics of the convection in the outer core. We performed the in situ viscosity measurement of the Fe-FeS melt under high pressure using X-ray radiography falling sphere method with a novel sample assembly. Viscosity was measures in the temperature, pressure, and compositional conditions of 1233-1923 K, 1.5-6.9 GPa, and Fe-Fe S (wt %), respectively. The viscosity coefficients obtained by 17 measurements change systematically in the range of 0.008-0.036 Pa s. An activation energy of the viscous flow, 30 kJ/mol, and the activation volume, 1.5 cm /mol, are determined as the temperature and pressure dependence, and the viscosity of the Fe S melt is found to be smaller than that of the Fe melt by 15 %. These tendencies can be well correlated with the structural variation of the Fe-FeS melt.

A buckling analysis of circular cylindrical shells under shear forces; An analytical study on buckling test

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PNC TN9410 93-086, 81 Pages, 1992/11

PNC-TN9410-93-086.pdf:3.19MB

Since vessels of fast breeder reactors (FBRs) are relatively thin wallcd, the prevention of buckling against seismic loading is one of the key issues in their structural design. This paper is the first report on buckling analysis by use of FEM to rationalize a design method for FBR components. In this paper, we conducted FEM analyses with the FINAS computer code modelling the test conditions precisely, especially the initial shape imperfections and material nonlinearity of the test specimens. Further, the effect of the initial shape imperfections on buckling strength was evaluated quantitatively, and the applicability of FEM to the present problem was studied. The following results were obtained. (1)It was confirmed that the initial shapes of test specimens could be modeled precisely by use of SAXON and the measured data by CIMD. (2)By modelling precisely the initial shape imperfections and material nonlinearity of the test specimens, FEM results agreed well with the test data in terms of the buckling strength, regardless of the buckling mode. The deferences of buckling strength between FEM and experiment results were within -2.5% 4.5% of experimental results. (3)Concerning the case in which the ratio of length to radius is 2.0, we confirmed that the buckling mode was changed by the existence of initial shape imperfections.