Alumina-silica glasses

Andrade, A. L., Ferreira, J. M. F. and Domingues, R. Z. (2004). Surface modifications of alumina-silica glass fiber. J. Biomed Mater. Res. Part B Applied Biomaterials 70B 378-383. 

Examples of commercial porous inorganic membranes are ceramic membranes (alumina, silica), glass and porous metals (stainless steel and silver). 

Despite control, few glass systems allow a match of thermal expansion coefficient to other important cell materials (typically alkaline earth-alumina-silica glasses). In any case, the cell materials don t match each other close enough to allow a rigid seal in larger cells... 

D.S. Tucker Dynamic fatigue of a lithia-alumina-silica glass-ceramic , J. Amer. Ceram. Soc. 73, 2528-2530 (1990)... 

T.J. Barry, L.A. Lay, R.P. Miller Nucleation efficiency in lithia-alumina-silica glasses . Discuss. Farad. Soc. 50, 214-221 (1970)... 

See Aluminum COMPOUNDS, aluminum oxide (alumina) Asbestos Glass Refractory fibers Silica. 

Fibrous oi cellular—mineral. Alumina, asbestos, glass, perlite, rock, silica, slag, or vermiculite. 

The resistance of PTFE to creep can be improved by blending in up to 25% of glass or asbestos fibre using PTFE dispersions as mentioned in the previous section. By the same technique alumina, silica and lithia may be incorporated to... 

The phase structure of glasses has a significant effect on their physical properties, which is discussed below with reference to chemical durability. The magnitude of the phase separation can be altered by heat treatment, and enhanced or reduced by the addition of various oxides to the melt. In particular, the addition of alumina to commercial soda-lime-silica glasses reduces the tendency to phase separation, improving chemical resistance (Doremus, 1973). A detailed study of the microstructure of soda-lime-silica glasses has been published by Burnett and Douglas (1970). The control of phase separation in the melt is now commercially important for processes such as the... 

A thin layer of adsorbent is applied to a support that may be a sheet of glass, metal, or plastic (Figure 13.4, D). Adsorbents are typically alumina, silica gel, or cellulose and may be mixed with gypsum to aid in adhering to the support. They may also include a fluorescent indicator that aids in visualization once the plate is developed. These adsorbents may also have hydrocarbons attached to them such that reverse-phase TLC can be carried out. 

PAHs adsorbed on particles of carbon black were also photostabilized (Behymer and Hites, 1988). However, Barofsky and Baum (1976) demonstrated that BaP, anthracene, BaA, and pyrene deposited on carbon microneedle field desorption emitters and exposed to UV radiation were all photooxidized to carbonyl compounds. Similarly, PAHs can photodegrade efficiently in air when adsorbed to substrates of silica gel, alumina, or glass plates (e.g., see Lane and Katz, 1977 Kormacher et al., 1980 Behymer and Hites, 1985 Yokely et al., 1986). 

The reactivity of each hydrocarbon was also studied on a variety of model adsorbents. All hydrocarbons are observed to be less photoreactive on coal ash surfaces than when adsorbed on alumina, silica, or glass surfaces. Different coal ashes stabilize polycyclic aromatic hydrocarbons to phototransformation with differing efficiencies. The role of the chemical composition of coal ashes (especially carbon and iron content) and physical properties of the ashes (especially color) is discussed. 

There are two ashes (KA and EA) on which none of the five PAHs exhibits detectable photoreactivity, and a third ash (IL) on which none of the PAHs examined thus far (excluding BaA) exhibits detect4-able photodecomposition. At the other extreme, all five PAHs undergo appreciable phototransformation when adsorbed on two ashes (TX and AR). In fact, for each, greater photochemical reactivity is observed on the Texas lignite ash than on any other ash (though less reactivity is observed on the TX ash than on alumina, silica, or glass adsorbents). 

Transhalogenation is also performed in the gas phase. The preferred catalysts are quaternary phosphonium salts supported on silica, alumina or glass beads which are applied in tubular reactor. At 140 °C, residence time of a few seconds is sufficient for 72-butyl bromide and -propyl chloride to equilibrate223. 

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