نتایج جستجو برای: amorphous silica

تعداد نتایج: 61469  

Journal: :International Journal of Technology: IJ Tech 2021

Geothermal silica is a potential source of amorphous for producing geopolymer concrete. The valorization geothermal as concrete provides an opportunity added value to the geothermal-based power industry. In

Journal: :Geochemical Transactions 2008
Susan A Carroll Sarah K Roberts Louise J Criscenti Peggy A O'Day

Strontium sorption to amorphous silica and goethite was measured as a function of pH and dissolved strontium and carbonate concentrations at 25 degrees C. Strontium sorption gradually increases from 0 to 100% from pH 6 to 10 for both phases and requires multiple outer-sphere surface complexes to fit the data. All data are modeled using the triple layer model and the site-occupancy standard stat...

Journal: :Langmuir : the ACS journal of surfaces and colloids 2006
Peter I Ravikovitch Alexander V Neimark

We present a novel quenched solid density functional theory (QSDFT) model of adsorption on heterogeneous surfaces and porous solids, which accounts for the effects of surface roughness and microporosity. Within QSDFT, solid atoms are considered as quenched component(s) of the solid-fluid system with given density distribution(s). Solid-fluid intermolecular interactions are split into hard-spher...

A. R. Mahjoub, A. R. Nilchi, S. Janitabar Darzi, S. Rasouli Garmarodi,

TiO2/SiO2 nanocomposite with molar ratio 1:1 was synthesized by a free calcination sol-gel method using titanium tetra chloride and tetraethylorthosilicate as raw materials. In the composite, TiO2 nanocrystals are highly dispersed in the amorphous SiO2 matrix and the mater showed size quantization effect arising from the presence of extremely small titanium oxide species having a low coordinati...

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 ...

2011
Hanae Saishu Atsushi Okamoto Noriyoshi Tsuchiya

The occurrences of silica deposits (quartz veins, silica sinters, silica scales) suggest that precipitation via nucleation and overgrowth on pre-existing mineral surfaces occurs under crustal conditions. We conducted hydrothermal flow-through experiments on silica precipitation using no mineral substrate at 120–430 °C and 31 MPa for understanding the effects of the aluminum on the mineralogy an...

Journal: :Environmental Health Perspectives 1997
L Mollo V Levresse M F Ottaviani S Ellouk-Achard M C Jaurand B Fubini

Stable radicals detectable by electron paramagnetic resonance (EPR) may be use in the investigation of early events in cell-particle toxicity. Piperidine-N-oxyl derivatives (nitroxides), covalently linked to the surface of a high surface area silica (used as model solid for the technique), served as probes in the investigation of the effects of incubation of silica particles with mesothelial ce...

Journal: :Journal of pharmaceutical sciences 2013
Yun Hu Pól Macfhionnghaile Vincent Caron Lidia Tajber Anne Marie Healy Andrea Erxleben Patrick McArdle

The formation and physical stability of amorphous sulfathiazole obtained from polymorphic forms I and III by cryomilling was investigated by X-ray powder diffraction (XRPD) and near-infrared (NIR) spectroscopy. Principal component analysis was applied to the NIR data to monitor the generation of crystalline disorder with milling time and to study subsequent recrystallization under different sto...

Journal: :Cement and Concrete Composites 2014

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