abstract self compacting concrete (scc) is a new construction material in the world. the aim of this research is to construct self compacting concrete with high compressive strength using combination of nano silica and micro silica. for this purpose, nano silica, micro silica, portland cement type 2, superplasticizer (sp), and gravel and sand have been used. three different groups of samples wi...

The authors’ research group has previously developed a novel method for the fabrication of silica/perfluoropolymer nanocomposites, wherein nano-sized silica particles without surface modification were dispersed uniformly through breakdown of loosely packed agglomerates of silica nanoparticles with low fracture strength in a polymer melt during direct melt-compounding. The method consists of two...

Exposure to respirable crystalline silica is a hazard common to many industries in Alberta but particularly so in abrasive blasting. Alberta occupational health and safety legislation requires the consideration of silica substitutes when conducting abrasive blasting, where reasonably practicable. In this study, exposure to crystalline silica during abrasive blasting was evaluated when both sili...

Silica-based materials with favourable biocompatibility are generally considered as excellent candidates for applications in biomedical fields. However, previous researches mainly focused on the safety of silica-based materials, their effects on osteogenic differentiation of human mesenchymal stem cells (hMSCs) still need further investigations. In this study, core-shell fluorescent silica nano...

In this study, nanosilica particles were prepared from self-made silica gel under the protection of citric acid in situ complexation and ethyl acetate as latent reagent. The effects acetate, acid, reaction temperature, time on particle size studied. optimum process parameters determined follows: Vethyl acetate: Vsilica sol = 9:50, addition amount 3.64%, 8 h, temperature 70 °C. products characte...

Silica fibers have been successfully used to deliver high-power high-energy laser beam in the near-infrared and visible range but suffer from high absorption color-center formation UV spectrum which disqualify them for such wavelength. Recently, advances of inhibited-coupling hollow-core photonic crystal made an unique tool transport radiation thanks ultralow overlap with silica cladding record...

alteration of ophiolitic ultramafic rocks, formation of listwaenite and associated mineralization are interesting phenomena of metallogeny of khoy ophiolite. it seems that the hydrothermal circulations responsible for mercury mineralization were derived from geothermal systems caused by intermediate to acidic magmatism in neogene-pleistocene time. reactivation of brecciated serpentinite with hy...

Freestanding and well-ordered two-dimensional (2D) silica monolayers with tetrahedral (T-silica) and octahedral (O-silica) building blocks are found to be stable by first-principles calculations. T-silica is formed by corner-sharing SiO4 tetrahedrons in a rectangular network, and O-silica consists of edge-sharing SiO6 octahedrons. Moreover, the insulating O-silica is the strongest silica monola...

A sustainable economy can be achieved only by assessing processes finalized to optimize the use of resources. Waste can be a relevant source of energy thanks to energy-from-waste processes. Concerns regarding the toxic fly ashes can be solved by transforming them into resource as recycled materials. The commitment to recycle is driven by the need to conserve natural resources, reduce imports of...