High-Pressure Research Applications Seminar

The United States‐Japan seminar on “High‐Pressure Research Applications in Geophysics and Geochemistry” was held in Honolulu, Hawaii, January 13–16, 1986, under the auspices of the National Science Foundation (NSF) and the Japan Society for the Promotion of Science (JSPS). The seminar, the third in a series, was cocovened by Murli H. Manghnani (University of Hawaii, Honolulu) and Syun‐iti Akimoto (University of Tokyo). Coming together for this symposium were 25 researchers from Japan, 22 from the United States, and four others, from Australia, the People's Republic of China, the Netherlands, and the Federal Republic of Germany. Of the 52 papers presented, 38 were presented orally at seven scientific sessions, and the rest were displayed at a poster session

Crystal structure of hydrous wadsleyite with 2.8% H 2 O and compressibility to 60 GPa

ABSTRACT Hydrous wadsleyite (β-Mg 2 SiO 4 ) with 2.8 wt% water content has been synthesized at 15 GPa and 1250 °C in a multi-anvil press. The unit-cell parameters are: a = 5.6686(8), b = 11.569(1), c = 8.2449(9) Å, β = 90.14(1)°, and V = 540.7(1) Å 3 , and the space group is I2/m. The structure was refined in space groups Imma and I2/m. The room-pressure structure differs from that of anhydrous wadsleyite principally in the increased cation distances around O1, the non-silicate oxygen. The compression of a single crystal of this wadsleyite was measured up to 61.3(7) GPa at room temperature in a diamond anvil cell with neon as pressure medium by X-ray diffraction at Sector 13 at the Advanced Photon Source, Argonne National Laboratory. The experimental pressure range was far beyond the wadsleyite-ringwoodite phase-transition pressure at 525 km depth (17

The effect of compressive strain on the Raman modes of the dry and hydrated BaCe0.8Y0.2O3 proton conductor

The BaCe0.8Y0.2O3-{\delta} proton conductor under hydration and under compressive strain has been analyzed with high pressure Raman spectroscopy and high pressure x-ray diffraction. The pressure dependent variation of the Ag and B2g bending modes from the O-Ce-O unit is suppressed when the proton conductor is hydrated, affecting directly the proton transfer by locally changing the electron density of the oxygen ions. Compressive strain causes a hardening of the Ce-O stretching bond. The activation barrier for proton conductivity is raised, in line with recent findings using high pressure and high temperature impedance spectroscopy. The increasing Raman frequency of the B1g and B3g modes thus implies that the phonons become hardened and increase the vibration energy in the a-c crystal plane upon compressive strain, whereas phonons are relaxed in the b-axis, and thus reveal softening of the Ag and B2g modes. Lattice toughening in the a-c crystal plane raises therefore a higher activation barrier for proton transfer and thus anisotropic conductivity. The experimental findings of the interaction of protons with the ceramic host lattice under external strain may provide a general guideline for yet to develop epitaxial strained proton conducting thin film systems with high proton mobility and low activation energy

Ultrasonic Velocities and Related Elastic Properties of Hawaiian Basaltic Rocks

Volume: 19Start Page: 291End Page: 29

Physical characterization of magmatic liquids : final report, August 15, 1985--February 28, 1991

Report Number(s)DOE/ER/13418--T1; OSTI ID: 10155518; Legacy ID: DE92015302This report describes a research project that was conducted from August 15, 1985 to February 28, 1992. The project was based on the ultrasonic studies of natural and synthetic silicate melts, and the study of Brillouin scattering of synthetic silicates and oxides. Measurements of the compressional wave velocity and attenuation can be established using the ultrasonic methods. Temperature dependences of silicates can be established by the Brillouin scattering. (MB)U.S. Department of EnergyDOE Contract Number: FG03-85ER1341

(Table 1) Consolidation test for sediments of ODP Leg 130 sites

Consolidation tests were performed on 19 samples of calcareous ooze from the Ontong Java Plateau, obtained during Ocean Drilling Program Leg 130. Rebound curves from consolidation tests on Ontong Java Plateau samples yield porosity rebounds of 1%-4% for these sediments at equivalent depths up to 1200 mbsf. The exception is a radiolarian-rich sample that has 6% rebound. A rebound correction derived from the porosity rebound vs. depth data has been combined with a correction for pore-water expansion to correct the shipboard laboratory porosity data to in-situ values. Comparison of the laboratory porosity data corrected in this manner with the downhole log data shows good agreement

Physical properties of ODP Hole 122-762C

Compressional velocity (Vp), shear velocity (Vs), compressional quality factor (Qp), electrical resistivity (p'), bulk density (pb), grain density (pg), and porosity (phi) were measured in our shore-based laboratory for 49 consolidated sediment samples from Hole 762C. The results are compared with shipboard data. Shore-based Vp values agree well with shipboard Vp data except in the range 670-820 meters below seafloor, where a shipboard calibration problem occurred. Shipboard sonic log data are an average of 0.3 km/s higher than shore-based Vp values because of in-situ overburden pressure. Shore-based pg and phi values are generally in agreement with shipboard data. However, shipboard pb values are consistently higher than shore-based data. This discrepancy is because the helium-displacement pycnometer used aboard ship gives erroneously low volumes for wet samples, which are then used in bulk density calculations. Correct shipboard wet sample volumes can be calculated by adding the difference between the wet and dry sample weights to the dry sample volume. The corrected shipboard pb values are in agreement with shore-based data. We recommend that the Ocean Drilling Program use this calculation in place of the pycnometer wet volumes. The chalks show a negative velocity gradient between 600 and 720 mbsf, though there is no apparent change in lithology. In absence of overpressuring and mineralogical changes, the negative gradient is probably caused by increasing porosity due to the change in microstructure of the sediment over this depth interval