Results 251 to 260 of about 155,593 (300)

Grinding and pozzolanic reactivity of quartz powders

Powder Technology, 1999
Abstract Cement-based materials are in wide use — partly in the belief that their reactivity is due to their glassy nature. The question we wish to investigate is: how specific is the link between the pozzolanic reaction and glassy materials? In order to answer it, we take the case of quartz, a material often used in cement-based matrices, reputed to
J.C Benezet, A Benhassaine
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Synthesis of powder-like fine crystalline quartz

High Pressure Research, 2001
Abstract A method of preparation of monodisperse powder-like fine crystalline quartz as separate well-faceted crystals of fixed size was developed. The size and habit of crystals are controlled during the process of their synthesis. The process is performed in two stages.
V. S. Balitsky, T. M. Bublikova, E. A. Marina, L. V. Balitskaya, Zh. S. Chichagova, H. Iwasaki, F. Iwasaki   +6 more
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Thermal infrared directional emissivity of powdered quartz

Journal of Geophysical Research: Solid Earth, 1995
Thermal infrared directional emissivity of quartz was measured for several particle size ranges and packing fractions. The samples measured were (1) a polished quartz slab; (2) a 75–250 μm powdered quartz sample, cleansed of clinging fines; (3) a 0–75 μm powdered quartz sample, sifted into a fairy castle structure; and (4) the same sample compressed to
Andrew E. Wald, John W. Salisbury
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Electrical conduction in quartz powder

Journal of Materials Science, 1980
Observations have been made on the direct current behaviour of crushed natural quartz at temperatures of the order of 1300 K in order to investigate the effect of applied electric fields on the impurities present in the samples. Migration of the alkaline impurities, leaving an alkali free layer adjacent to the anode, has been detected by analysis of ...
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Determination of Amorphous Phase in Quartz Powder by X-Ray Powder Diffractometry

Powder Diffraction, 1989
AbstractA powder diffraction method was applied to the quantitative analysis of amorphous silica in several quartz powders. Two calibration methods, i.e., direct analysis and the standard addition method were examined. Calibration mixtures were made by mixing a standard silica gel powder ground to under 5 μm particle size with a matrix quartz powder ...
Toshihiro Nakamura, Katsumi Sameshima, Kiyoyuki Okunaga, Yoshitaka Sugiura, Jun Sato   +4 more
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Effect of agglomeration purification of quartz powders on the quality of quartz glass

Glass and Ceramics, 2009
The effect of agglomeration purification of quartz powders on the quality of quartz glasses obtained using quartz raw materials from the “Berkutinskaya” and No. 175 veins of the Kyshtym deposit is studied. Analysis of the optical transmission spectra and the structural characteristics of the glasses made shows that agglomeration purification of the ...
R. Sh. Nasyrov, A. S. Lebedev, R. T. Zainullina   +2 more
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The triboelectric separation of quartz—calcite and quartz—apatite powders after chemical conditioning

Powder Technology, 1977
Abstract Quartz—calcite and quartz—apatite mixtures in their natural state cannot readily be separated by triboelectric means, since all three minerals acquire a negative charge after contact with common metals. Adsorption of oleate ions from aqueous solution lowers the surface work function of the minerals to such an extent that while the ...
M.J. Pearse, M.I. Pope
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Vacuum sintering of quartz powder and phase transformation of quartz

Vacuum, 1961
Abstract The process of the phase transformation of quartz to silica glass in the range of heating time 10–120 min at the pressure of 10 −5 Torr is as follows: At the heating temperature below about 1700°C Quartz→silica glass→cristobalite; At the heating temperature above about 1700°C Quartz→silica glass.
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Limiting density behavior of quartz powders

Powder Technology, 1969
Abstract An experimental study into the effects of varying particle characteristics on maximum and minimum bulk densities of dry quartz powders is presented. The characteristics which were varied are particle size, particle size distribution (or gradation), and particle shape.
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Dynamical properties of epoxy composites filled with quartz powder

Journal of Alloys and Compounds, 2000
Abstract The dynamical mechanical properties of epoxy composites filled with different amounts of quartz powder were investigated. The loss tangent and the storage Young’s modulus were measured at frequencies between 5 and 323 Hz with a tension–compression device, from room temperature up to 460 K.
S.N Goyanes, J.D Marconi, P.G König, M.D Martin, I Mondragon   +4 more
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