نتایج جستجو برای: silicates
تعداد نتایج: 5604 فیلتر نتایج به سال:
The 8–14 µm emission spectra of 12 T Tauri stars in the Taurus/Auriga dark clouds and in the TW Hydrae association obtained with the Infrared Spectro-graph (IRS 1) on board Spitzer are analyzed. Assuming the 10 µm features originate from silicate grains in the optically thin surface layers of T Tauri disks, the 8–14 µm dust emissivity for each object is derived from its Spitzer spectrum. The em...
This report reviews the safety of Aluminum, Calcium, Lithium Magnesium, Lithium Magnesium Sodium, Magnesium Aluminum, Magnesium, Sodium Magnesium, and Zirconium Silicates, Magnesium Trisilicate, Attapulgite, Bentonite, Fuller’s Earth, Hectorite, Kaolin, Montmorillonite, Pyrophyllite, and Zeolite as used in cosmetic formulations. The common aspect of all these claylike ingredients is that they c...
Portland cement could be produced by heating the raw materials (clay, limestone) about 1500°C which clinker will be formed. Geochemical and mineralogical studies of clinker, Portland cement, cement kiln dust and cement mill dust have been carried out by optical microscopy, X-ray diffraction and X-ray florescence. In phase system diagram (CaO-Al2O3-SiO2), chemical components of clinker cement oc...
Introduction: Magnesian silicates such as for-sterite (Mg 2 SiO 4) and enstatite (MgSiO 3) are major minerals in universe including disks around young stars [e.g., 1], shells around evolved stars, in particular, oxygen rich stars [e.g., 2, 3] and so on. It is thus important to understand evaporation and condensation behaviors of magnesian silicates, which are major phase-transformation reaction...
Mineralogical and geochemical investigations indicate two general stages of skarnification i.e, prograde and retrograde stages in the Mohammad-Abad district, south west of Yazd province. Metasomatic skarn (Prograde stage) occurred with precipitation of anhydrous calc-silicate mineral assemblages (andradite and diopside- hedenbergite) within the temperature ranges of 470 to 550 ºC. During the re...
Abstract We present the magnetic, structural and 57 Fe Mossbauer characterization of soils collected from an ancient mercury contaminated city named Huancavelica in Peru. The results indicate that silicates carbonates are main mineralogical constituents samples. In addition, Mössbauer spectra at room temperature reveal, presence two components: a magnetic component related to Fe-oxides (magneti...
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