نتایج جستجو برای: polymorph crystalline silica
تعداد نتایج: 77663 فیلتر نتایج به سال:
Tridymite, a low-pressure, high-temperature (>870 °C) SiO2 polymorph, was detected in a drill sample of laminated mudstone (Buckskin) at Marias Pass in Gale crater, Mars, by the Chemistry and Mineralogy X-ray diffraction instrument onboard the Mars Science Laboratory rover Curiosity The tridymitic mudstone has ∼40 wt.% crystalline and ∼60 wt.% X-ray amorphous material and a bulk composition wit...
Two new crystalline polymorphs and an amorphous phase of the active curcuminoid ingredient in turmeric are reported. Curcumin polymorph 2 has higher dissolution rate and better solubility than the known polymorph 1.
Ultrathin crystalline silica layers grown on a Mo~112! substrate have been shown to be a useful silica model oxide support in surface science model catalyst studies. As the oxide support material plays an important role in the catalytic process, a multitechnique surface science study is presented to characterize the morphological and electronic properties of the heteroepitaxial system SiO2 /Mo(...
“Silica,” is a term which refers broadly to the mineral compound silicon dioxide (SiO2). Silica can be crystalline or amorphous. Crystalline silica is significantly more hazardous to employees than amorphous silica. In addition to causing the disabling and irreversible lung disease known as silicosis, crystalline silica has been classified as a human carcinogen by the International Agency for R...
Omar Bagasra, Mohammed Alsayari, Rebecca Bullard-Dillard and Mohamed A Daw (1) Department of Biology, South Carolina Center for Biotechnology and Department Pathology, Microbiology and Immunology, School of Medicine, University of South Carolina. (2) Department of Biology, Claflin University (3) Department of Medical Microbiology and Immunology, Faculty of Medicine, Al-Fateh University, Tripoli...
In various shocked meteorites, low-pressure silica polymorph α-cristobalite is commonly found in close spatial relation with the densest known SiO2 polymorph seifertite, which is stable above ∼80 GPa. We demonstrate that under hydrostatic pressure α-cristobalite remains untransformed up to at least 15 GPa. In quasi-hydrostatic experiments, above 11 GPa cristobalite X-I forms-a monoclinic polymo...
Background: Silicosis as a most important work-related lung disease is generated of inhalation crystalline silica dust. Chemicals health risk assessment is essential to decide on priorities for control action and reduce the risk to an acceptable level. The aim of this study is evaluate workers' exposure to crystalline silica (quartz) and determine the qualitative and quantitative health risk le...
Volcanic ash is a heterogeneous mineral dust that is typically composed of a mixture of amorphous (glass) and crystalline (mineral) fragments. It commonly contains an abundance of the crystalline silica (SiO2) polymorph cristobalite. Inhalation of crystalline silica can induce inflammation by stimulating the NLRP3 inflammasome, a cytosolic receptor complex that plays a critical role in driving ...
Introduction: Occupational exposure to crystalline silica increases the risk of lung cancer and restrictive lung disease with extensive fibrosis. Silica dust is a major health hazard in foundry factories. The aim of this study was to determine core making workers’ exposure to respirable crystalline silica dust in a foundry factory. Material and Method: This cross-sectional study was conducte...
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