Decomposition of kyanite and solubility of Al2O3 in stishovite at high pressure and high temperature conditions     

Xi Liu  Norimasa Nishiyama  Takeshi Sanehira  Toru Inoue  Yuji Higo  Shizue Sakamoto 《Physics and Chemistry of Minerals》2006,33(10):711-721

In order to constrain the high-pressure behavior of kyanite, multi-anvil experiments have been carried out from 15 to 25 GPa, and 1,350 to 2,500°C. Both forward and reversal approaches to phase equilibria were adopted in these experiments. We find that kyanite breaks down to stishovite + corundum at pressures above ∼15 GPa, and stishovite + corundum should be the stable phase assemblage at the pressure–temperature conditions of the transition zone and the uppermost part of the lower mantle of the Earth, in agreement with previous multi-anvil experimental studies and ab initio calculation results, but in disagreement with some of the diamond-anvil cell experimental studies in the literature. The Al₂O₃ solubility in nominally dry stishovite has been tightly bracketed by forward and reversal experiments; it is slightly but consistently reduced by pressure increase. Its response to temperature increase, however, is more complicated: increases at low temperatures, maximizes at around 2,000°C, and perhaps decreases at higher temperatures. Consequently, the Al₂O₃ solubility in dry stishovite at conditions of high temperature–high pressure is very limited.  相似文献   

Waveform inversion in the frequency domain for the simultaneous determination of earthquake source mechanism and moment function   总被引：3，自引：0，他引：3  

M. Nakano  H. Kumagai  H. Inoue 《Geophysical Journal International》2008,173(3):1000-1011

  相似文献   

Northward-propagating nighttime medium-scale traveling ionospheric disturbances observed with SuperDARN Hokkaido HF radar and GEONET     

Akimitsu Ichihara  Nozomu Nishitani  Tadahiko Ogawa  Takuya Tsugawa 《极地研究(英文版)》2013,24(1)

  相似文献   

Mass Discharge in a Tracer Plume: Evaluation of the Theissen Polygon Method     

Douglas M. Mackay  Murray D. Einarson  Phil M. Kaiser  Mamie Nozawa‐Inoue  Sham Goyal  Irina Chakraborty  Ehsan Rasa  Kate M. Scow 《Ground water》2012,50(6):895-907

A tracer plume was created within a thin aquifer by injection for 299 d of two adjacent “sub‐plumes” to represent one type of plume heterogeneity encountered in practice. The plume was monitored by snapshot sampling of transects of fully screened wells. The mass injection rate and total mass injected were known. Using all wells in each transect (0.77 m well spacing, 1.4 points/m² sampling density), the Theissen Polygon Method (TPM) yielded apparently accurate mass discharge (M_d) estimates at three transects for 12 snapshots. When applied to hypothetical sparser transects using subsets of the wells with average spacing and sampling density from 1.55 to 5.39 m and 0.70 to 0.20 points/m², respectively, the TPM accuracy depended on well spacing and location of the wells in the hypothesized transect with respect to the sub‐plumes. Potential error was relatively low when the well spacing was less than the widths of the sub‐plumes (>0.35 points/m²). Potential error increased for well spacing similar to or greater than the sub‐plume widths, or when less than 1% of the plume area was sampled. For low density sampling of laterally heterogeneous plumes, small changes in groundwater flow direction can lead to wide fluctuations in M_d estimates by the TPM. However, sampling conducted when flow is known or likely to be in a preferred direction can potentially allow more useful comparisons of M_d over multiyear time frames, such as required for performance evaluation of natural attenuation or engineered remediation systems.  相似文献   

Relating food and human hair to assess mercury exposure levels in Poboya,Central Sulawesi,Indonesia     

M. M. Sari  T. Inoue  Y. Matsumoto  K. Yokota 《International Journal of Environmental Science and Technology》2017,14(3):463-472

Poboya is a major small-scale gold-mining area in Central Sulawesi, Indonesia, that has been operating since 2009. About 200–500 kg of mercury is released each day as a result of gold-mining activities over a total area of 7000 ha. We examined mercury contamination by using two types of sample, namely food and human hair. Samples were obtained in Poboya and in the city of Palu, 11 km away. Samples of 22 foods were obtained from traditional markets in Poboya and Palu. Total mercury concentrations ranged from 0.003 to 0.31 µg/g in foods from Poboya and from 0.001 to 0.13 µg/g in those from Palu. The highest total mercury concentration in Poboya was found in unripe banana, which is frequently consumed by the local people. In Poboya, the weekly mercury intakes from foods were calculated at 180.3 µg/person from vegetables, 1.7 µg/person from processed foods, 51.4 µg/person from seafood, and 17.2 µg/person from meat and eggs. In Palu, the weekly mercury intakes were 2.9 µg/person from vegetables, 3.1 µg/person from processed foods, 60.8 µg/person from seafood, and 19 µg/person from meat and eggs. These findings delineated Poboya as an area polluted by mercury contamination. Intake of mercury-contaminated food influenced the results obtained in human hair. Hair concentrations of total mercury in Poboya ranged from 0.3 to 19.6 µg/g.  相似文献   

Coastal upwelling along the north coast of Papua New Guinea and El Niño events during 1981–2005     

Takuya Hasegawa  Kentaro Ando  Keisuke Mizuno  Roger Lukas  Bunmei Taguchi  Hideharu Sasaki 《Ocean Dynamics》2010,60(5):1255-1269

We investigate the relationship between sea surface temperature (SST) cooling and upwelling along Papua New Guinea’s (PNG) north coast before the onset of El Niño events using a hindcast experiment with a high-resolution ocean general circulation model. Coastal upwelling and related SST cooling appear along PNG north coast during the boreal winter before the onsets of six El Niño events occurring during 1981–2005. Relatively cool SSTs appear along PNG north coast during that time, when anomalous northwesterly surface wind stress, which can cause coastal upwelling by offshore Ekman transport appearing over the region. In addition, anomalous cooling tendencies of SST are observed, accompanying anomalous upward velocities at the base of the mixed layer and shallow anomalies of 27°C isotherm depth. It is also shown that entrainment cooling plays an important role in the cooling of the mixed layer temperature in this region.  相似文献   

Crustal structure of central Japan and its petrological implications     

Oguz Ozel  Takaya Iwasaki  Takeo Moriya  Shin'ichi Sakai  Takuya Maeda  Chengshi Piao  Toshikatsu Yoshii  Shinya Tsukada  Akihito Ito  Masayuki Suzuki  Akira Yamazaki  & Hiroki Miyamachi 《Geophysical Journal International》1999,138(1):257-274

  相似文献   

Organic matters and acid‐sulfate alteration in Itomuka mercury mine,Hokkaido, Japan: Implications for the transportation and deposition mechanisms of Hg     

Takuya Echigo  Mitsuyoshi Kimata  Masahiro Shimizu 《Resource Geology》2020,70(2):204-213

In order to examine the transportation and deposition mechanisms of Hg, we investigated the ore and hydrothermal alteration minerals and solid organic matters from Itomuka mercury mine located in the eastern part of central Hokkaido. In addition to the ore minerals, native mercury and cinnabar, quartz, marcasite, alunite, kaolinite, and minor amounts of pyrite and smectite were identified in the Hg ore by powder X‐ray diffraction (XRD) analysis. This mineral assemblage of acid sulfate alteration was likely developed under the conditions of low temperature (≤100°C) and low pH (≤2) in the steam‐heated environment. The H₂SO₄ was produced above the water table by the oxidation of H₂S separated from deep, near‐neutral fluids by boiling. The dominance of native mercury over cinnabar in Hg ore indicates that the greater part of mineralized Hg was transported as Hg⁰ in aqueous solution and vapor with low sulfur fugacity. The solid organic matters found in the Hg ore were analyzed with SEM‐EDS, micro‐XRD, and micro‐Fourier transform infrared (FTIR) spectroscopy, and these results suggest that the organic matters contributed to keeping the low fO₂ of the Hg‐bearing fluid and transportation of Hg as Hg⁰ in S‐poor condition. Because the solubility of Hg in acidic fluid is low, neutral to alkaline fluid seems to have leached Hg from the basement sedimentary rocks of Hidaka Group which also supplied the organic matters to the fluid. The oxidation and cooling of Hg‐bearing solution and vapor triggered the deposition of liquid Hg as a primary phase.  相似文献   

Optimum strength ratio of hysteretic damper     

Kazuo Inoue  Susumu Kuwahara 《地震工程与结构动力学》1998,27(6):577-588

This paper deals with steel moment frames combined with hysteretic dampers. Specifically, it examines the strength of dampers required to minimize damage to moment frames under earthquake loading. The important structural variables are the ratio of the dampers' shear strength to the maximum resistance, termed β in this study, and the relative stiffness between the damper and the main frame, termed k. The equivalent viscous damping ratio of the entire structural system is affected by the quantities β and k and the ductility ratio of the main frame. The optimum dampers' strength ratio (β_opt), which maximizes the equivalent viscous damping ratio, was formulated as a function of k, and it was found that β_opt is independent of the ductility ratio of the main frame. Earthquake response analysis confirmed that damage to the main frame can be significantly reduced by hysteretic dampers and minimized at the value of β_opt. © 1998 John Wiley & Sons, Ltd.  相似文献   

The international at-sea intercomparison of fCO₂ systems during the R/V Meteor Cruise 36/1 in the North Atlantic Ocean     

Arne Krtzinger  Ludger Mintrop  Douglas W. R. Wallace  Kenneth M. Johnson  Craig Neill  Bronte Tilbrook  Philip Towler  Hisayuki Y. Inoue  Masao Ishii  Gary Shaffer  Rodrigo F. Torres Saavedra  Eiji Ohtaki  Eiji Yamashita  Alain Poisson  Christian Brunet  Bernard Schauer  Catherine Goyet  Greg Eischeid 《Marine Chemistry》2000,72(2-4)

The ‘International Intercomparison Exercise of fCO₂ Systems’ was carried out in 1996 during the R/V Meteor Cruise 36/1 from Bermuda/UK to Gran Canaria/Spain. Nine groups from six countries (Australia, Denmark, France, Germany, Japan, USA) participated in this exercise, bringing together 15 participants with seven underway fugacity of carbon dioxide (fCO₂) systems, one discrete fCO₂ system, and two underway pH systems, as well as systems for discrete measurement of total alkalinity and total dissolved inorganic carbon. Here, we compare surface seawater fCO₂ measured synchronously by all participating instruments. A common infrastructure (seawater and calibration gas supply), different quality checks (performance of calibration procedures for CO₂, temperature measurements) and a common procedure for calculation of final fCO₂ were provided to reduce the largest possible amount of controllable sources of error. The results show that under such conditions underway measurements of the fCO₂ in surface seawater and overlying air can be made to a high degree of agreement (±1 μatm) with a variety of possible equilibrator and system designs. Also, discrete fCO₂ measurements can be made in good agreement (±3 μatm) with underway fCO₂ data sets. However, even well-designed systems, which are operated without any obvious sign of malfunction, can show significant differences of the order of 10 μatm. Based on our results, no “best choice” for the type of the equilibrator nor specifics on its dimensions and flow rates of seawater and air can be made in regard to the achievable accuracy of the fCO₂ system. Measurements of equilibrator temperature do not seem to be made with the required accuracy resulting in significant errors in fCO₂ results. Calculation of fCO₂ from high-quality total dissolved inorganic carbon (C_T) and total alkalinity (A_T) measurements does not yield results comparable in accuracy and precision to fCO₂ measurements.  相似文献