نتایج جستجو برای: hydrothermal alterations

تعداد نتایج: 127690  

Journal: :Trends in biochemical sciences 2004
Michael J Russell William Martin

Geologists have suggested that life might have emerged at hydrothermal vents, chemists have shown that metal sulphides such as FeS and NiS can catalyse biochemical reactions in the absence of proteins, and biologists have suggested that the acetyl-coenzyme-A (CoA) pathway of CO2 fixation might be very ancient. New findings from the enzymes at the heart of the acetyl-CoA pathway, carbon monoxide...

2017
Camille Crouzet Fabrice Brunet Nadir Recham Anne-Line Auzende Nathaniel Findling Valérie Magnin Jean-Henry Ferrasse Bruno Goffé

The effect of acidic conditions (in a pH range of 3 to 6) and temperature on the kinetics of the hydrothermal oxidation of ferrous iron contained in BOF steel slag has been tested in the 150–350C range for acid acetic concentrations from 0 to 4M. Reaction progress was monitored with the amount of produced H2. Higher temperature and lower pH are found to enhance the hydrothermal oxidation kineti...

2003
J. A. Hurowitz S. M. McLennan

Introduction: On Mars, the geomorphology of numerous surface features has been attributed to the interaction of magmatic and impact heat sources with an H 2 O-rich Martian crust/megaregolith [1-3]. In addition , geochemical analyses of soil at the Pathfinder and Viking landing sites indicate high concentrations of SO 3 and Cl [4-6], consistent with interaction between a basaltic protolith and f...

Journal: :international journal of nano dimension 0
s. sabbaghi nano chemical engineering dep. of shiraz university, shiraz, iran. h. orojlou nano technology research institute, shiraz university, shiraz, iran. m. r. parvizi research and development of boualisina petrochemical company,mahshahr, iran. r. saboori nano technology research institute, shiraz university, shiraz, iran. m. sahooli nano chemical engineering dep. of shiraz university, shiraz, iran.

in the past decades, many methods have been developed to synthesize zero- dimensional  nanoparticles, quasi–one–dimensional (1d) cuo nanostructures, such as metal organic deposition technique,  microwave irradiation, sol-gel-like dip  technique, reverse micelle-assisted route, chemical method, and simple template free solution route. among those synthesis methods, hydrothermal and chemical reac...

2016
Sébastien Duperron Adrien Quiles Kamil M. Szafranski Nelly Léger Bruce Shillito

Citation: Duperron S, Quiles A, Szafranski KM, Léger N and Shillito B (2016) Estimating Symbiont Abundances and Gill Surface Areas in Specimens of the Hydrothermal Vent Mussel Bathymodiolus puteoserpentis Maintained in Pressure Vessels. Front. Mar. Sci. 3:16. doi: 10.3389/fmars.2016.00016 Estimating Symbiont Abundances and Gill Surface Areas in Specimens of the Hydrothermal Vent Mussel Bathymod...

2011
David J. Hall

INTRODUCTION The term epithermal derives from the genetic classification scheme for hydrothermal ore deposits proposed by Lindgren (1933). On the basis of stratigraphic relationships in volcanic sequences, and by analogy with mineral and metal occurrences and mineral textures in active hydrothermal systems, Lindgren inferred that epithermal deposits formed at <200°C and <100 atmospheres (~100 b...

Journal: :journal of chemical and petroleum engineering 2011
amin bazyari yadollah mortazavi abbas ali khodadadi negahdar hosseinpour mitra bahri

nay zeolites with different framework si/al ratios were synthesized via hydrothermal technique. structural characteristics of the synthesized zeolites were determined by using xrd, xrf, sem, bet analyses. the effects of operating conditions of hydrothermal dealumination, i.e. time, temperature and partial pressure of water vapor on dealumination of the y zeolites framework and their structure w...

Journal: :geopersia 2014
maryam sheibi

exact petrography and mineral chemistry investigations of pristine and altered rocks of the post-eocene panj-kuh pluton show thatsubsequent to emplacement and crystallization, rocks were subjected to two secondary composition equivalents, sodic-calcic andpotassic alterations, respectively. fresh rocks have syenitic composition and contain plagioclase (labradorite), k-feldspar, magmaticdiopside,...

2006
Ken Takai Satoshi Nakagawa Anna-Louise Reysenbach Joost Hoek

Over the past two decades, microbiologists have gained significant insights into the diversity and physiology of microbial communities associated with deep-sea hydrothermal systems. Much of the initial research focused on mid-ocean ridge (MOR) systems; however, because of the greater heterogeneity of vent fluid chemistry and sulfide structures from back-arc basin (BAB) systems, recent studies h...

2012
Nur Syafinaz Ridhuan Khairunisak Abdul Razak Zainovia Lockman Azlan Abdul Aziz

In this study, zinc oxide (ZnO) nanorod arrays were synthesized using a simple hydrothermal reaction on ZnO seeds/n-silicon substrate. Several parameters were studied, including the heat-treatment temperature to produce ZnO seeds, zinc nitrate concentration, pH of hydrothermal reaction solution, and hydrothermal reaction time. The optimum heat-treatment temperature to produce uniform nanosized ...

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