Results 241 to 250 of about 507,192 (288)

Thermodynamic Properties of Methane Hydrate in Quartz Powder

The Journal of Physical Chemistry B, 2007
Using the experimental method of precision adiabatic calorimetry, the thermodynamic (equilibrium) properties of methane hydrate in quartz sand with a grain size of 90-100 microm have been studied in the temperature range of 260-290 K and at pressures up to 10 MPa.
Vitaly P, Voronov, Evgeny E, Gorodetskii, Sergey S, Safonov   +2 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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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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Determination of Amorphous Phase in Quartz Powder by X-Ray Powder Diffractometry

Powder Diffraction, 1989
Abstract A 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 ...
Toshihiro Nakamura, Katsumi Sameshima, Kiyoyuki Okunaga, Yoshitaka Sugiura, Jun Sato   +4 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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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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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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Hydrothermal synthesis of mono-dispersed quartz powders

Journal of Materials Science, 2004
The hydrothermal method was first used for crystallization of quartz in the middle of 19th century, and has been developed to grow large single crystals of quartz industrially [1]. On the other hand, the hydrothermal method has been recognized as an excellent method to prepare ceramic powders [2].
K. Yanagisawa, Y. Zhu, A. Onda, K. Kajiyoshi   +3 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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