Fiber float

Since must be less than 90°, 6 in this case need only be greater than 0.2°. If 6 is, for example, 5° (about as low a value as can be distinguished from zero by direct observation) becomes 85.2°, and the fiber floats with a 9.6° arc of dry cylindrical surface between C and C. ... 

In principle, the capillary depression caused by a fiber floating on a liquid surface can be used to calculate the contact angle 7], In practice, however, the relatively small depth of immersion can make it difficult to obtain sufficient accuracy. Recently, a technique utilizing image analysis has been developed to analyze the capillary rise profile around fibers or cylinders 79],... 

Rags to be made into paper are first sorted, and any unsuitable ones are discarded. Seams are opened, and nonfabric materials, such as buttons, are removed. The rags are chopped into small pieces and then cleaned by boiling them in strong cleansing solutions. Next, they are rinsed and beaten while damp until all of the threads have disintegrated and the fibers float freely in water. This is the paper pulp. 

Fiber float A warp or filling fiber that lies on top of the opposite series of yarn for a distance of several fibers. 

Note The fiber float test is simple and quick to run. Keep in mind that the problem must be massive in order for the biocide application to be economical and to justify the program costs. 

After about 4 to 12 hours the hides are drained, then floated with lime without additional sulfides. The dmm or hide processor is mn at slow speeds intermittently during the unhairing process. The continued action of the lime solution on the hides brings the pH to 12—13. At this pH the hides swell to about twice the original thickness. This swelling has a beneficial opening of the fibers to permit better tannage (Fig. 3a). 

Kaolin, usually air-floated, is an essential ingredient in continuous filament fiber glass and significant quantities are used in this appHcation (24). 

The premise that discontinuous short fibers such as floating catalyst VGCF can provide structural reinforcements can be supported by theoretical models developed for the structural properties of paper Cox [36]. This work was recently extended by Baxter to include general fiber architecture [37]. This work predicts that modulus of a composite, E can be determined from the fiber and matrix moduli, Ef and E, respectively, and the fiber volume fraction, Vf, by a variation of the rule of mixtures,... 

Composites fabricated with the smaller floating catalyst fiber are most likely to be used for applications where near-isotropic orientation is favored. Such isotropic properties would be acceptable in carbon/carbon composites for pistons, brake pads, and heat sink applications, and the low cost of fiber synthesis could permit these price-sensitive apphcations to be developed economically. A random orientation of fibers will give a balance of thermal properties in all axes, which can be important in brake and electronic heat sink applications. 

Vapor-grown carbon fibers have been prepared by catalyzed carbonization of aromatic carbon species using ultra-fine metal particles, such as iron. The particles, with diameters less than 10 nm may be dispersed on a substrate (substrate method), or allowed to float in the reaction chamber (fluidized method). Both... 

Fig. 3. Vapor-grown carbon fibers obtained by substrate method w ith diameter ca. 10 /xrn (a) and those by floating catalyst method (b) (inserted, low magnification).

FIGURE 19.12 A rather crude nylon fiber. can be made by dissolving the salt of an amine in water and dissolving the acid in tfcg a layer of hexane, which floats on the water. The polymer forms at the interface f of the two lavers, and a long string can be slowly pulled out. 

Almost all fiber and partial titanium dioxide can be recovered from white water by DAF under full flow pressurization mode43 with chemical addition. On June 10, 1982, at Mead Corporation, pulp was prepared with 40% cotton fiber and 60% wood fiber. The loading of titanium dioxide was about 50% (i.e., 273 kg Ti02 per 600 kg total pulp). The white water from No. 2 machine was fed to a DAF cell (diameter = 3 m) at 15.8 L/s (250gal/min) under full flow pressurization mode. Turkey red oil (TRO) was dosed as a flotation aid at 80mL/min. The influent white water (before TRO addition), DAF effluent, and floated scum were sampled for analysis. The DAF influent had 98 mg/L of TSS, and 650 NTU of turbidity at pH 9.27. The DAF effluent had 15 mg/L TSS and 550 NTU of turbidity at pH 9.25. Although TSS (fiber and titanium dioxide) recovery rate was 85%, the ash content (titanium dioxide) of the recovered TSS was very low. Therefore, using a DAF clarifier under full flow pressurization mode and TREO, the majority of fibers in white water but only about half of titanium dioxide can be recovered. 

In practical applications, adequate coagulants should be chosen based on the quality of the floated scum (i.e., recovered titanium dioxide and fiber mixture), which is intended to be reused in the paper manufacturing process. The reused titanium dioxide and fibers should not adversely affect the quality of the paper. 

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