We present a molecular dynamics simulation study of the crystal growth of methane hydrates in the presence of model silica (SiO(2)) surfaces. The crystal growth under apparent steady-state conditions shows a clear preference for bulk solution. We observe rather disordered water arrangements very close to the silica surface within about 5 Å in both liquid and crystalline regions of the system. T...

A two-part experiment using bubble rafts to analyze amorphous structures is presented. In the first part, the distinctions between crystalline and vitreous structures are examined. In the second part, the interface between crystalline and amorphous regions is considered. Bubble rafts are easy to produce and provide excellent analogy to recent research results on the atomic structure of silica g...

Recently, a number of reports have been published on silicosis in workers exposed to artificial quartz conglomerates containing high levels of crystalline silica particles (70-90%) used in the construction of kitchen and bathroom surfaces. Three cases of silicosis in workers exposed to artificial quartz conglomerates are reported. The diagnosis was derived from both the International Labour Off...

Ordered mesoporous Cd(x)Zn(1-x)S ternary compound semiconductors were prepared with a simple nano-casting method using 3-D cubic Ia3d meso-structured silica, KIT-6, as a hard-template with the easily available precursors of 3CdSO4 x 8H2O and ZnSO4 x 7H2O. Thermal reduction of impregnated precursors resulted in the crystalline networks within the mesopore of the silica template, then the ordered...

Copyright 2012 KIEEME. All rights reserved. This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Effect of Silica Content on the Dielectric Prope...

Silicon and oxygen are the two most abundant elements in the Earth's crust but despite the vast scientific literature on crystalline and amorphous silica, new chemistries, structures and applications continue to be discovered for compounds formed from these elements--thus we present here for the first time the formation of new amorphous silica structures that were uniquely synthesized by a bioi...

The interface between a crystalline and a vitreous phase of a thin metal supported silica film was studied by low temperature scanning tunneling microscopy. The locally resolved evolution of Si-Si nearest neighbor distances and characteristic angles was evaluated across the border. Furthermore, we investigated the behavior of the ring size distribution close to the crystalline-vitreous transiti...

Silicosis is an occupational lung disease caused by inhalation of crystalline silica. People working in occupations like sandblasting, surface drilling, tunneling, silica flour milling, ceramic making, and so forth are predisposed to develop silicosis. Crystalline forms of silica are more fibrogenic than the amorphous forms, highlighting the importance of the physical form in pathogenesis. Lung...

Crystalline polymorphism of organic semiconductors is among the critical factors in determining the structure and properties of the resultant organic electronic devices. Herein we report for the first time a solvent-type-dependent polymorphism of a long fused-ring organic semiconductor and its crucial effects on charge transport. A new polymorph of 5,11-bis(triethylsilylethynyl)anthradithiophen...

An epidemiological investigation was undertaken to determine the relationship between silicosis in hardrock miners in Ontario and cumulative exposure to silica (crystalline silica--alpha quartz) dust. This first report describes the cohort, the method of classifying the radiographs, and the identification of a case of silicosis.