نتایج جستجو برای: hydrothermal alterations
تعداد نتایج: 127690 فیلتر نتایج به سال:
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...
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...
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...
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...
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...
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...
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...
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,...
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...
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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