نتایج جستجو برای: convectional hydrothermal

تعداد نتایج: 17082  

Journal: :Applied and environmental microbiology 2003
Mausmi P Mehta David A Butterfield John A Baross

The subseafloor microbial habitat associated with typical unsedimented mid-ocean-ridge hydrothermal vent ecosystems may be limited by the availability of fixed nitrogen, inferred by the low ammonium and nitrate concentrations measured in diffuse hydrothermal fluid. Dissolved N2 gas, the largest reservoir of nitrogen in the ocean, is abundant in deep-sea and hydrothermal vent fluid. In order to ...

2014
Shaoni Sun Xuefei Cao Shaolong Sun Feng Xu Xianliang Song Run-Cang Sun Gwynn Lloyd Jones

BACKGROUND The recalcitrance of lignocellulosic biomass is a major limitation for its conversion into biofuels by enzymatic hydrolysis. The use of a pretreatment technology is an essential step to diminish biomass recalcitrance for bioethanol production. In this study, a two-step pretreatment using hydrothermal pretreatment at various temperatures and alkali fractionation was performed on eucal...

Journal: :پژوهش های تولید گیاهی 0
ابوالفضل درخشان جاوید قرخلو

the hydrothermal time models have been widely applied to describe the germination responses of seeds to temperature and water potential. in this study, three hydrothermal time models developed on the basis of different statistical distributions (normal, weibull and gumbel) were compared to describe the phalaris minor seed germination. results showed that gumbel (aicc=-762.8) and weibull (aicc=-...

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 ...

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