نتایج جستجو برای: convectional hydrothermal
تعداد نتایج: 17082 فیلتر نتایج به سال:
In this paper, we focus on the controlled growth mechanism of α-Fe2O3 nanostructures via the hydrothermal method. The field emission scanning electron microscopy (FESEM) results reveal that at a lower hydrothermal time, the initial nucleation involves the formation of short and thin β-FeOOH nanorods. The subsequent increase in the hydrothermal time leads β-FeOOH to form thicker and longer nanor...
Thirty years after the first discovery of high-temperature submarine venting, the vast majority of the global mid-ocean ridge remains unexplored for hydrothermal activity. Of particular interest are the world's ultraslow spreading ridges that were the last to be demonstrated to host high-temperature venting but may host systems particularly relevant to prebiotic chemistry and the origins of lif...
[1] An extensive deep-tow magnetic survey of the TAG ridge segment on the MidAtlantic Ridge reveals new information about the relationship between the magnetic anomaly field and the TAG hydrothermal deposits. Results show the strongest magnetization is located over the neovolcanic axis and asymmetrically toward the western side of the central Brunhes anomaly. A well-defined linear magnetization...
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...
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