نتایج جستجو برای: hydrothermal

تعداد نتایج: 16947  

2000
M. Sharma

We present Os data for axial high-temperature and off-axial low-temperature hydrothermal solutions from the Juan de Fuca Ridge. The high-temperature, H2S-bearing axial fluids have unradiogenic Os isotopes pointing to a nearly complete domination of osmium isotopes from the basalts during hydrothermal circulation. The ridge axis fluids typically do not show large enrichment in osmium concentrati...

2006
Giora Proskurowski Marvin D. Lilley Deborah S. Kelley Eric J. Olson

Although commonly utilized in continental geothermal work, the water–hydrogen and methane–hydrogen isotope geothermometers have been neglected in hydrothermal studies. Here we report δD-CH4 and δD-H2 values from high-temperature, black smoker-type hydrothermal vents and low-temperature carbonate-hosted samples from the recently discovered Lost City Hydrothermal Field. Methane deuterium content ...

2017
Jebin Ryu Hun Wook Lee Junho Yoon Bumjoon Seo Dong Eui Kwon Un-Moo Shin Kwang-joon Choi Youn-Woo Lee

BACKGROUND Panax ginseng Meyer is cultivated because of its medicinal effects on the immune system, blood pressure, and cancer. Major ginsenosides in fresh ginseng are converted to minor ginsenosides by structural changes such as hydrolysis and dehydration. The transformed ginsenosides are generally more bioavailable and bioactive than the primary ginsenosides. Therefore, in this study, hydroth...

Journal: :Dental materials : official publication of the Academy of Dental Materials 2014
M Cattani-Lorente S S Scherrer S Durual C Sanon T Douillard L Gremillard J Chevalier A Wiskott

OBJECTIVES Implant surface modifications are intended to enhance bone integration. The objective of this study was to assess the effect of different surface treatments on the resistance to hydrothermal degradation, hardness and elastic modulus of a 3Y-TZP ceramic used for dental implants. METHODS Samples grouped according to their surface morphologies (AS, as-sintered; C, coated; P, dry-polis...

Journal: :Remote Sensing 2017
Qing-Jun Xu Fawang Ye Shao-Feng Liu Zhi-Xin Zhang Chuan Zhang

The Baiyanghe uranium deposit is a currently important medium-sized deposit in the Xuemisitan area, Xinjiang. The hydrothermal alteration in this deposit is closely related to the uranium mineralization of the deposit. In this study, hyperspectral data are collected from drill cores in the Baiyanghe uranium deposit using a FieldSpec4 visible-shortwave infrared spectrometer to study the hydrothe...

2014
Xiaoning He Brian J. Anderson

This paper is an update of an earlier supply analysis, He, et al., (2013), of low-temperature utilization of geothermal resources using geothermal district heating and cooling systems. Along with the use of identified hydrothermal resources, it updates the supply curve for direct-use utilization using undiscovered hydrothermal resources and near-hydrothermal EGS resources. It also incorporates ...

2017
David Deamer Bruce Damer

Enceladus is a target of future missions designed to search for existing life or its precursors. Recent flybys of Enceladus by the Cassini probe have confirmed the existence of a long-lived global ocean laced with organic compounds and biologically available nitrogen. This immediately suggests the possibility that life could have begun and may still exist on Enceladus. Here we will compare the ...

Journal: :international journal of nano dimension 0
a. khanfekr department of metallurgical and materials engineering, iran university of science and technology (iust), narmak, tehran, iran. m. tamizifar department of metallurgical and materials engineering, iran university of science and technology (iust), narmak, tehran, iran. r. naghizadeh department of metallurgical and materials engineering, iran university of science and technology (iust), narmak, tehran, iran.

nano-sized batio3 powders with particular nb concentrations were prepared by rotary- hydrothermal (rh) method. hydrothermal method was used at 180 °c for 5 hours with new ti pressure and the teflon vessel was rotated at a speed of 160 rpm during the hydrothermal reaction. new hydrothermal method was used instead of previous solid state reaction for the system batio3±nb2o3 in high temperature to...

2004
Thomas Pichler Jan Veizer

The fringing reef in Tutum Bay on the west side of Ambitle Island, Papua New Guinea is the only presently known coral reef exposed to the extensive discharge of a hot, mineralized hydrothermal fluid. There, aragonite and ferrihydrite, a hydrous ferric oxide, are the prominent hydrothermal precipitates. Aragonite forms two distinct crystal habits, (a) euhedral (pseudohexagonal) crystals up to 2 ...

2018
Cherisse Du Preez Charles R. Fisher

Since the discovery of hydrothermal vents 40-years ago, long-term time-series have focused on mid-ocean ridge systems. Based on these studies, hydrothermal vents are widely considered to be dynamic, ephemeral habitats. Under this premise, national, and international regulatory bodies are currently planning for the commercial mining of polymetallic sulfide deposits from hydrothermal vents. Howev...

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