نتایج جستجو برای: clay minerals
تعداد نتایج: 41990 فیلتر نتایج به سال:
The major element composition, including two kinds of clay minerals and moisture content of sound-producing sand are reported for the first time. Sand from 33 beaches in Japan has been found to make sound. Ten sound-producing beaches were selected to compare with silent beach sand. Both sound-producing sand and silent beach sand are mostly composed of quartz and feldspar. The range of SiO2 cont...
Introduction: Over 13 years after landing at Meridiani Planum and in her 10 extended mission, Mars Exploration Rover Opportunity continues to explore the rim of ~22 km diameter Endeavour crater [1]. The rim exposes material that is older than the S-rich, layered sedimentary rock covering the Meridiani plains and filling much of the interior of Endeavour. Clay mineral exposures at the rim have b...
This study was conducted to elucidate the dynamic aspects of the adsorption-desorption of borate ions on edge surfaces of 2:1 clay minerals. A pressure-jump relaxation method was used to evaluate the elementary processes involved in the adsorption-desorption of borate ions by pyrophyllite in aqueous media at pH 9 and ionic strength of 0.01 (NaNOj). This clay was selected because of the small de...
AB S T R A C T : The Fourier transform Raman spectra of the kaolinite minerals have been measured in the 50-3800 cm -1 region using near infrared spectroscopy. Kaolinites are characterized by remarkably intense bands in the 120-145 cm -I region. These bands, attributed to the O-Si--O and O-A1-O symmetric bending modes, are both polymorph and orientation dependent. The 200-1200 cm -I spectral ra...
solution potassium (so-k) and exchangeable k (ex-k) extracted by nh4oac are the major sources of potassium used by plants, but initially non-exchangeable k (nex-k) can also contribute significantly to plant uptake. perennial ryegrass (lolium perenne, cv. roper) was successively planted in ten surface soil samples with different clay mineralogical composition belonging to five soil types to dete...
Zan lateritic horizon is located about 25 km southeast of Damavand, Tehran Province. This horizon developed as stratiform in lower part of shales and sandstones of Shemshak Formation (Jurassic). Mineralogical investigations show that diaspore, hematite, goethite, anatase, and kaolinite are the principal minerals of this horizon accompanied by lesser amounts of accessory minerals like boehmite, ...
Since the antiquity, and on an empirical basis, man has accumulated experience on the benefits and risks of minerals (such as, special clay, mud and sand) and other mineral resources (such as, salt, sea water, spring water, underground water, volcanic emissions and dust) on human health. Man and minerals are chemical systems sharing a common composition, comprising major, minor and trace chemic...
[1] Phyllosilicates have previously been detected in layered outcrops in and around the Martian outflow channel Mawrth Vallis. CRISM spectra of these outcrops exhibit features diagnostic of kaolinite, montmorillonite, and Fe/Mg-rich smectites, along with crystalline ferric oxide minerals such as hematite. These minerals occur in distinct stratigraphic horizons, implying changing environmental c...
The formation of fossil oil within clay minerals i.e. mineral-catalyzed decarboxylation, is a mechanism awaiting a thorough chemical explanation. To contribute to such an explanation, the study presented here investigates this mechanism at the level of first principles, electronic structure computations, employing density functional theory (DFT plus Hubbard U), planewaves, pseudopotentials and ...
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