deterioration of concrete structures in the gulf region is a serious problem. penetration of chloride ion into concrete is responsible for such early deterioration. determination of chloride diffusion coefficient is an effective way to predict the service life of concrete structures. in order to investigate the performance of concrete mixtures in such environments, ordinary and silica fume conc...

The emergence of complex nano- and microstructures is of fundamental interest, and the ability to program their form has practical ramifications in fields such as optics, catalysis, and electronics. We developed carbonate-silica microstructures in a dynamic reaction-diffusion system that allow us to rationally devise schemes for precisely sculpting a great variety of elementary shapes by diffus...

Nanochannels fabricated in fused silica substrates are ideal tools for single (bio)molecular studies in biology and are promising in the development of innovative applications in chemistry. To obtain a higher throughput and a higher level of integration and functionalization, nanochannels with high aspect ratios and nano-in-nano structures are very much desired, but their fabrication is a chall...

In this paper the influence of two different sizes of silica particles (micro-silica and nano-silica) was studied on mechanical properties of sulfur and sulfur composite. To improve the structural properties, sulfur was plasticized using dicyclopentadiene (DCPD) and methyl styrene (MSt). Plasticized sulfur composite was prepared by melt blending of plasticized sulfur and silica particles. T...

Objective(s): Enzyme immobilization via nanoparticles is perfectly compatible against the other chemical or biological approximate to improve enzyme functions and stability. In this study lactoperoxidase was immobilized onto silica-coated magnetite nanoparticles to improve enzyme properties in the presence of cadmium chloride as an inhibitor. Materials and Methods:  The process consists of the ...

Nano silica-H2SO4 is an efficient and mild catalysis system for the regeneration of aldehyde from aldoximes. Ketoximes are converted to amides by Beckmann rearrangement in the presence of nano silica-H2SO4. The reactions are carried out in solvent-free conditions under microwave irradiation (600 W) within 50-120 sec in good yields.

Meso-porous metal materials have enhanced surface energies offering unique surface properties with potential applications in chemical catalysis, molecular sensing and selective separation. In this paper, commercial 20 nm diameter metal nano-particles, including silver and copper were blended with 7 nm silica nano-particles by shear mixing. The resulted powders were cold-sintered to form dense, ...

In this research work, silica nano-porous thin films were deposited on glass substrates by layer by layer method. The thin films were calcinated at various calcination temperatures (200, 300, 400, and 500 °C). The morphology, surface characteristics, surface roughness and hydrophilic properties of the thin films were investigated by field emission scanning electron microscopy, attenuated total ...

A series of concrete slabs were cast with 0, 7, and 12% by mass silica fume replacement of cement at W/CM = 0.35, 0.40, and 0.45. After either moist or steam curing, a variety of chloride resistance tests were performed. These included AASHTO T259, modified T259, T277, as well as several bulk diffusion tests and sorptivity tests. Results indicate that the use of properly dispersed silica fume r...

Nano silica-H2SO4 is an efficient and mild catalysis system for the regeneration of aldehyde from aldoximes. Ketoximes are converted to amides by Beckmann rearrangement in the presence of nano silica-H2SO4. The reactions are carried out in solvent-free conditions under microwave irradiation (600 W) within 50-120 sec in good yields.