We have examined the atomic dynamics of the brittle fracture process in amorphous silica using molecular dynamics. Under strain, extensive atomic restructuring occur in the vicinity of voids leading to the formation of 2membered (2-M) silica rings that are much different than the open network structure of the bulk. The sequence of events that lead to the formation of the 2-M rings was character...

Z. Naturforsch. 55 b, 459—461 (2000); received February 21, 2000 Biomineralization, Silica, Silicon-Accumulating Plants A series of silicon-accumulating plants [different Equisetum (horse tail) species, Echium vulgare, and Symphytum officinale] were studied by solid-state 29Si NMR experiments. For this purpose, selected parts of these plants were freeze-dried and then investigated by solid-stat...

Young basalts from Kilauea Volcano, Hawai'i, frequently feature opaque surface coatings, 1–80 μm thick, composed of amorphous silica and Fe-Ti oxides. These coatings are the product of interaction of the basaltic surface with volcanically-derived acidic fluids. Previous workers have identified these coatings in a variety of contexts on Hawai'i, but the timescales of coating development, coating...

Catalytic emulsion polymerization of ethylene with nickel catalysts in the presence of silica nanoparticles affords stable dispersions of silica/polyethylene nanocomposite particles. The modification of the surface of silica particles by grafting upon their surface of octenylor octylsilanes is a prerequisite for obtaining composites. Different morphologies of composites particles were observed ...

A simple, convenient, reusable, and inexpensive airand water-purification unit including a one-end sealed porous amorphous-silica (a-silica) tube coated with TiO2 photocatalyst layers has been developed. The porous a-silica layers were formed through outside vapor deposition (OVD). TiO2 photocatalyst layers were formed through impregnation and calcination onto a-silica layers. The resulting por...

Objective(s): This paper describes coating of magnetite nanoparticles (MNPs) with amorphous silica shells.   Materials and Methods: First, magnetite (Fe3O4) NPs were synthesized by co-precipitation method and then treated with stabilizer molecule of trisodium citrate to enhance their dispersibility. Afterwards, coating with silica was carried out via a sol-gel approach in which the electrostati...

The studies of irradiation damage in silica are of significant interest because of its application in nuclear reactors, nuclear waste containers, optical fibers, and semiconductor devices [1,2]. Although there are a number of publication showing the effect of electrons, ions, protons, alpha-particles irradiation on microstructural changes of silica, understanding deformation behavior under appl...

Despite the widespread use of amorphous aluminosilicates (ASA) in various industrial catalysts, the nature of the interface between silica and alumina and the atomic structure of the catalytically active sites are still subject to debate. Here, by the use of dynamic nuclear polarization surface enhanced NMR spectroscopy (DNP SENS) and density functional theory (DFT) calculations, we show that o...

Water is used globally for cooling purposes in industry. During its re-use, scaling and deposition can develop due to the high content of dissolved species. Among the toughest to combat is silica scale, or amorphous silicon dioxide. In this paper, we present how certain chemical interventions in the water chemistry can be beneficial for inhibiting silica polycondensation. Specifically, we have ...