Cavitation bubbles occur in fluids subjected to rapid changes in pressure. We use billion-atom reactive molecular dynamics simulations on a 163,840-processor BlueGene/P supercomputer to investigate damage caused by shock-induced collapse of nanobubbles in water near an amorphous silica surface. Collapse of an empty bubble generates a high-speed nanojet, which causes pitting on the silica surfac...

In this study, Santa Barbara Amorphous (SBA-15) mesoporous silica has been functionalized with aminopropyl groups that were converted to propargyl-bearing moieties through the reaction with propargyl bromide. The material then underwent an efficient Cu(I)-catalyzed azide alkyne click reaction with sodium azide in order to obtain the corresponding triazole products. The covalent modification of ...

The toxicity and ecotoxicity effects, handling disposal of synthetic amorphous silica nanoparticles aerogels are reviewed discussed.

Introduction: The secondary mineralogy of martian surface materials is consistent with aqueous alteration of mafic and ultramafic rocks [e.g., 1-3]. Alteration of mafic silicates results in the release of SiO2 into aqueous solution, followed by the precipitation of silica [4] and/or silica-rich minerals. The presence of these phases is consistent with data obtained at the Mars Pathfinder [4] an...

An atomic force microscope (AFM) was used to measure the interactions between a flat Teflon AFTM surface and an -alumina or amorphous silica sphere in cyclohexane as a function of distance of separation. Repulsive van der Waals (vdW) forces were predicted for the interactions between Teflon AFTM and -alumina or amorphous silica according to the negative Hamaker constants, which were calculated ...

Glasses are usually shaped through the viscous flow of a liquid before its solidification, as practiced in glass blowing. At or near room temperature (RT), oxide glasses are known to be brittle and fracture upon any mechanical deformation for shape change. Here, we show that with moderate exposure to a low-intensity (<1.8×10(-2) A cm(-2)) electron beam (e-beam), dramatic shape changes can be ac...

A number of studies have suggested that the irradiation behavior and damage processes occurring during sequential and simultaneous particle irradiations can significantly differ. Currently, there is no definite answer as to why and when such differences are seen. Additionally, the conventional multi-particle irradiation facilities cannot correctly reproduce the complex irradiation scenarios exp...

The formation of ordered particle arrays plays an essential role in nanotechnology, biological systems, and inorganic photonic structures in the geosphere. Here, we show how ordered arrays of amorphous silica spheres form in deeply weathered lithologies of the Great Artesian Basin (central Australia). Our multi-method approach, using optical and scanning electron microscopy, X-ray microdiffract...

Respiratory manifestations among 41 workers exposed to amorphous silica dust were compared with a control group comprising 90 workers of equivalent socioeconomic state in the same plant. Flow volumes were determined, blood gas concentrations were measured at rest and during exercise, chest radiographs were obtained, and data about respiratory symptoms were collected by questionnaire. A dust exp...

The distribution of Ge-O-Ge and Si-O-Si bond angles α in amorphous germania and silica is re-determined on the basis of diffraction experiments. The bond angle α joining adjacent tetrahedra is the central parameter of any continuous random network description (CRN) of these glasses. New high energy photon diffraction experiments on amorphous germania (at photon energies of 97 and 149 keV) are p...