Sigma fiber

Another CVD type silicon carbide fiber available commercially, is called Sigma fiber. Sigma fiber filament is a continuous silicon carbide monofilament obtained by CVD on a trmgsten substrate. Figure 6.19 gives the flow diagram for the fabrication of this process. 

Figure 6.19 Flow diagram for fabrication of the Sigma fiber.

The fiber fraction was washed several times with water, ratio 1 5, the washings being added to the starch fraction (Figure 2). Final traces of starch were removed from the fiber by incubation with 2% alpha-amylase (Sigma Chemical Co., type V-A from hog pancreas) for 16 hr at 37°C, and washing several times with distilled water before freeze-drying. 

Guo. Z.X. and Derby, B. (1994). Interfaces in TijAI composites reinforced with SIGMA SiC fibers. Scripta Metall. Mater. 30, 89-94,... 

All chemicals were of analytical grade and obtained from Sigma (St. Louis, MO) with the exception of bacto agar, yeast extract and peptone which were obtained from Merck (Darmstadt, Germany), and D-glucose, which was obtained from VWR. Solka-floc, a delignified pine pulp serving as the cellulosic substrate, was obtained from Fiber Sales Development (Urbana, OH). For the preparation of solutions and media, distilled water was used. 

R. E. Shirey and R. F. Mindrup, SPME-Adsorption versus Absorption Which Fiber Is Best for Your Application product literature, T400011, Sigma-Aldrich Co., 1999. 

The most significant aspect of a well-designed fiber-reinforced composite is that its end use performance may be predicted from the properties of each constituent.f In recent years. Quality by Design and Design for Six Sigma have advocated a set of predictive methodologies and protocols that ensure the delivered goods meet the market demands. Elastic constants can be predicted for continuous reinforced... 

Optiblanc. P-V Sigma Prodotti Chimid] Additives for detergents, textiles, paper, plastics optical brightener fw fibers. 

Molecular structures of the above mentioned dyes are presented in Figure 5. The dyes were purchased from Sigma-Aldrich (Germany) and used witliout further purification. These dyes were selected for the studies because they are extensively used in the textile industry. C.I. Acid Orange 7 is applied for fibers such as silk, wool and nylon using neutral to acid dye baths. Direct Blue 71 is used for cotton, paper, leather, wool, silk and nylon dyeing. Reactive dyes, e.g. RB5, are by far the best choice for dyeing of cotton and other cellulose fibers. 

Figure 1.9 (a) A commercial SPME unit with the coated fiber (b) inserted into a sample vial. Reprinted with permission of Supelco, Bellefonte, PA 16823, USA (www.sigma-aldrich.com). 

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