نتایج جستجو برای: carbonate formation
تعداد نتایج: 548632 فیلتر نتایج به سال:
Copper-zinc superoxide dismutase (SOD) is of fundamental importance to our understanding of oxidative damage. Its primary function is catalysing the dismutation of superoxide to O(2) and H(2)O(2). SOD also reacts with H(2)O(2), leading to the formation of a strong copper-bound oxidant species that can either inactivate the enzyme or oxidise other substrates. In the presence of bicarbonate (or C...
Density functional theory (DFT) calculations have been used to investigate the oxidative carbonylation of methanol on Pd(II)/β zeolite. Activation energies for all the elementary steps involved in the commonly accepted mechanism, including the formation of dimethyl carbonate, methyl formate and dimethoxymethane, are presented. Upon conducting the calculations, we identify that the Pd(2+) cation...
Potentiometric measurements of Yttrium and Rare Earth Element (YREE) complexation by carbonate and bicarbonate indicate that the quality of carbonate complexation constants previously obtained via solvent exchange analyses are superior to characterizations obtained using solubility and adsorptive exchange analyses. The results of our analyses at 25°C are combined with the results of previous so...
The bulk etch rate for CR-39 in NaOH/ethanol was faster than those in aqueous solution of NaOH (NaOH/H2O). Furthermore, a layer of precipitate always accumulates on the surface of CR-39 detector during etching in NaOH/ethanol, which is absent during etching in NaOH/H2O. In the present work, mass spectrometry results have shown that the same etched products are present in the etchants of NaOH/H2...
Human-induced ocean acidification and warming alter seawater carbonate chemistry reducing the calcification of reef-building crustose coralline algae (CCA), which has implications for reef stability. However, due to the presence of multiple carbonate minerals with different solubilities in seawater, the algal mineralogical responses to changes in carbonate chemistry are poorly understood. Here ...
Hydrous alteration of olivine is capable of producing molecular hydrogen (H2) under a wide variety of hydrothermal conditions. Although olivine hydrolysis (i.e., serpentinization) has commonly been assessed at elevated temperatures (4100 1C), the nature of these reactions in relation to H2 production at lower temperatures has not been systematically evaluated, especially with regard to carbonat...
Ž . The vesicular, fine-grained A horizon Av is the widespread, ubiquitous surficial horizon of desert soils in diverse landforms and parent materials of varying ages. Now known to form mostly through accumulation of eolian dust, recent studies show that dust accumulation and concomitant soil development are genetically linked to stone pavement formation. Changes in the magnitude of eolian acti...
The Dorood oilfield is located offshore in the northern part of the Persian Gulf. It partly underlies the Kharg Island. The Neocomian Fahliyan Formation represents the high-quality reservoir in the oilfield. It includes five carbonate members: The Manifa, Middle and Upper Yamama, Khami and Lower Ratawi. The Fahliyan Formation in the studied well attains a thickness of 378.1 m and mainly consist...
The Oligo-miocene Asmari formation is one of the most important hydrocarbon reservoirs in the southwest of Iran. In order to evaluate reservoir quality and the factors controlling reservoir properties, detailed geological and petrophysical studies were carried out on 242 m of core samples from Asmari reservoir. This study is a part of a larger project that examines depositional history and rese...
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