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Showing 1 to 20 of 22 for “"Crystalline silica"”.
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Characterization of amorphous silica and crystalline silica from rice husk ash on water filtration application
… at low-cost production and using an effectively silica from natural waste rice husk was evaluated. Rice husk was fired at 700ºC and 1000ºC respectively and produced rice husk ash which mutated to amorphous and crystalline silica. Five samples were fabricated after been mixed with the compositions …
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Rapid FTIR analysis for respirable crystalline silica monitoring in coal mines using readily available sampling equipment
… mine dust (RCMD) in conjunction with respirable crystalline silica (RCS). Overexposure can pose serious health risks, including development of coal workers' pneumoconiosis (CWP) (also known as "black lung"). CWP has the potential to progress to a more consequential form known as progressive …
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Molecular Dynamics Simulations of Structural Transitions in Crystalline and Amorphous Inorganic Compounds
… insights into the transformation mechanisms of crystalline silica, (ii) discovered the structure of high-density C-III cristobalite (a phase that has been known to exist but was never indexed), (iii) revealed a ubiquitous tendency for oxygen ordering in various high-density crystalline phases of …
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Characterization of pozzolanic cement for radioactive waste disposal
… material varied from approximately 90% crystalline silica with the welded tuff to over 95% crystalline silica with the unwelded tuff from Yucca Mountain; The results indicated that the particular volcanic tuff from Yucca Mountain, Nevada, is not a good pozzolan because it has poor …
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Organochlorine Pesticide Residue in Fish Fillets From Lake Springfield, Missouri
… Elut cartridge (65% Diatomaceous Earth and 35% crystalline silica). The solution was collected after it has passed through the cartridge and an additional 50 mL of hexane was passed through the cartridge. The collected solution was then transferred to a round bottom flask and reduced to 3 mL by …
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Fabrication, characterisation and properties of polysiloxane rice husk silica composites
The polysiloxane silica composites were fabricated and characterised as to elucidate the feasibility of casting (CA) and compression (CO) method. Besides, the contribution of rice husk silica (RHA SiO2) and crystalline silica (CS) in enhancing the composites properties were also investigated. …
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Molecular Simulation of Zeolites by Machine-Learned Potentials
… learned potential to simulate amorphous and crystalline silica at time scales previously unavailable for simulations with near ab initio accuracy. The second work will focus on models trained using more accurate meta-GGA level DFT calculations for silica, while the final works will focus on …
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A Mineralogical and Geochemical Assessment of the Potential Respiratory Health Hazard of Ash from Sakurajima Volcano, Japan.
… the most recent eruptive phase. The amount of crystalline silica was investigated to determine the potential for the development of chronic respiratory diseases. In general ~7 wt. % cristobalite was found, but no other silica polymorphs were observed. SEM imaging showed no fibrous particles …
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Effects of water on chemomechanical instabilities in amorphous silica : nanoscale experiments and molecular simulation
… the tensile failure mechanism of amorphous silica and the effects of water on the process, combining: (a) atomic force microscope (AFM) bending tests, (b) molecular dynamics (MD) simulation and (c) molecular orbital (MO) simulation. Bending tests of silica nanowires provide validation for …
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Appalachian Coal Miners At Greater Risk For Silica Exposure than Rocky Mountains
… health effects of occupational exposure to silica dust include silicosis and an increased risk of lung cancer. This study estimates the effect of regional location on coal mine employee exposure to crystalline silica, and the odds of a coal workers pneumoconiosis diagnosis. </p> <p>Study …
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Role of scavenger receptor MARCO in particle uptake and lung inflammation
… exposure to environmental particulates such as crystalline silica (CSiO2). The chronic inflammatory process triggered by CSiO2 is known to culminate into a fibrotic response called silicosis in the human lungs. Previous studies have indicated the role of membrane glycoproteins called scavenger …
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Role of scavenger receptor MARCO in particle uptake and lung inflammation
… exposure to environmental particulates such as crystalline silica (CSiO2). The chronic inflammatory process triggered by CSiO2 is known to culminate into a fibrotic response called silicosis in the human lungs. Previous studies have indicated the role of membrane glycoproteins called scavenger …
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Toward Rapid Silica Analysis of CPDM Samples using Portable Fourier Transform Infrared Spectrometry
… they are unable to directly assess respirable crystalline silica (RCS) concentrations, which are linked to the recent rise of respiratory diseases among coal miners. This incompatibility is due to the composition of the CPDM's internal filter stub. The stub consists of a fibrous borosilicate …
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Silica modified Co3O4 nanocubes as a model system for metal-support interaction in Co/SiO2 catalyst for Fischer-Tropsch synthesis
… study was to study the interaction between the silica and cobalt crystallites using a model of Co3O4-nanocubes whose surface was modified with tetraethyl orthosilicate. The model systems were prepared in two steps, viz. synthesis of the cobalt(III,II) oxide nanocubes via the sodium …
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Model systems for the investigation of metal-support interactions in cobalt based Fischer-Tropsch
… dilute solution of an alkoxide, tetraethyl orthosilicate (TEOS) or triphnyl ethoxy silane (TPEOS), Co-O-Si bond (ligand) is expected to form until it reaches equilibrium state. The concentration of the dilute alkoxide solution can be varied to observe its effect on the surface coverage of the Co …
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Analytical methods to investigate occupational exposure to toxic elements and their species
… arsenic, hexavalent chromium and respirable crystalline silica (RCS). Current biological monitoring methods are either no longer deemed fit for purpose (arsenic), not ideal (chromium) or are not available (RCS). The limitations of occupational exposure assessment of hexavalent chromium and …
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Application of a TGA Method to Estimate Coal, Carbonate, and Non-carbonate Mineral Fractions as a Proxy for the Major Sources of Respirable Coal Mine Dust
… of respirable coal mine dust (RCMD) and crystalline silica have been on a downward trend. This contradiction has prompted keen interest in detailed characterization of RCMD to shed light on dust constituents-and their sources. Such information might help miners understand where and under …
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Demonstration of Direct-on-filter FTIR to Estimate Silica, Kaolinite, and Calcite Mineral Fraction in Respirable Coal Mine Dust Samples
… to coal, RCMD can contain minerals such as crystalline silica (i.e., most often present as quartz). There has been a resurgence of lung diseases among US coal miners since the late-1990s which has emphasized the need for better quartz monitoring, and better dust characterization in general. …
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The impacts and conflicts associated with defunct gold tailings storage facilities in South Africa: A case study of Davidsonville, Central Rand
… season, but the dust has been proven to contain crystalline silica and radionuclides. The long-term exposure to this dust can lead to skin problems and respiratory illnesses. There is higher exposure of ambient particulate matter (PM10) in areas around tailings even at distances up to 2 km …
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Investigating the Effects of Particle Loading and Agglomeration on Respirable Coal Mine Dust Particle Classification by SEM-EDX
… the late 1990s. Coal miners are also exposed to crystalline silica, which can lead to a lung disease known as silicosis. While coal mining related disease is on the rise, the historic dust monitoring data does not indicate such a striking resurgence. As a result, there has been an increased …
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