Fiber capillary action

Fiber capillary action Apart from improved adsorption of biological fluids thanks to fiber high surface ratio, capillary action of fibers also contributes to cells adhesion onto the fibrous implantable medical device. Capillarity is the action by which pores in a solid transport liquid on contact, so that tissue fluids transfer from the wet end to the dry end. The kinetics of the fluid transport are governed by the surface tension... 

Directed Oxidation of a Molten Metal. Directed oxidation of a molten metal or the Lanxide process (45,68,91) involves the reaction of a molten metal with a gaseous oxidant, eg, A1 with O2 in air, to form a porous three-dimensional oxide that grows outward from the metal/ceramic surface. The process proceeds via capillary action as the molten metal wicks into open pore channels in the oxide scale growth. Reinforced ceramic matrix composites can be formed by positioning inert filler materials, eg, fibers, whiskers, and/or particulates, in the path of the oxide scale growth. The resultant composite is comprised of both interconnected metal and ceramic. Typically 5—30 vol % metal remains after processing. The composite product maintains many of the desirable properties of a ceramic however, the presence of the metal serves to increase the fracture toughness of the composite. 

From the physics point of view, cellulose fibers can indeed be considered as tiny roughly cylindrical capillary tubes of radius r and length h. Consequently, a wetting liquid placed into contact with this highly hydrophilic material penetrates it by capillary action. Actually, in capillaries with radii much smaller than the capillary length, gravity may be... 

By retrieving Eq. (12) with the characteristic fiber s parameters defined in Fig. 1.10, the characteristic time required to completely fill the fiber s lumen by capillary action may be expressed as ... 

FIGURE 1.10 From the physics point of view, a fiber may be seen as a tiny capillary tube which gets invaded by a wetting liquid placed into contact with one of the fiber s tip V is the velocity of the liquid edge advancing over the fiber, and u is the velocity at which the meniscus advances inside the fiber s lumen by capillary action (Liger-Belair et al., 2005b). 

Modified Cross Sections. Nylon filaments are spun in a variety of cross-section shapes that include the conventional round to irregular solid and hollow shapes (Fig. 13). The cross-section shape is an important variant in designing the functionality and luster of fibers. The round cross section is used for strength in industrial applications and for subdued luster in apparel and upholstery. The multilobal cross sections are used to enhance bulk and for bright luster in both BCF and spun staple yams for carpets and upholstery. The grooves in the multilobal shapes also enhance moisture transport by wicking water through capillary action. Flat-sided ribbon-like cross sections provide cover in apparel applications. 

Fig. 17. Fiber-optic refractive index sensor. Fluid of interesl is drawn by capillary action into a duct through a glass substrate. The effective path length varies in proportion with the refractive index. (Yazbak, Foxboro, Massachusetts)...

Paper towels mop up water spills by capillary action within the narrow channels between the fibers of the paper. 

If the cylinder is extremely narrow, a thin film of water will be drawn upward. Narrow tubes are called capillary tubes. This movement of a liquid such as water is called capillary action, or capillarity. Capillary action helps explain how paper towels can absorb large amounts of water. The water is drawn into the narrow spaces between the cellulose fibers in paper towels by capillary action. In addition, the water molecules form hydrogen bonds with cellulose molecules. These same factors account for the absorbent properties of disposable diapers. Water is drawn from the surface of the diaper to the interior by capillary action. The diaper can absorb about 200 times its mass in fluid. 

The Mounting Pin. In this laboratory the best results have been obtained with a specially designed mounting pin, illustrated in Figure 1. The pin is a hollow copper rod with a diameter corresponding to the adaptor hole in the goniometer head (normally 3 mm or 0.125 in). The tip of the pin is tapered down to 0.5 mm. The bore diameter near the tip is -0.5 mm the rest of the bore is 1.5 mm. In preparation for use the fine bore hole is filled with standard electronic solder (by capillary action). A glass fiber of... 

Instant thin layer chromatography (ITLC) plates are prepared from ground-up glass fibers impregnated with silica gel. This provides a uniform plate, readily wetted by the more polar solvents so capillary action is rapid. The plates are fragile and should be handled accordingly. 

A bundle of fibers that by CAPILLARY action draw-up a steady supply of liquid (often of melted fuel to be burned). Operation of some TABLETTING PRESSES by which the DIE descends over a fixed lower punch to reduce density variation in the TABLET and facilitate removal of the COMPACT. 

Fibers and filaments with larger microchannels, deep grooves, as well as hollow fibers induce improved capillary action that, in addition to adsorption phenomenon onto fiber surface, encourages cells adhesion but also cell infiltration and migration compared to round section fibers. Fiber topography is thus a tunable parameter to control cell migration, either to promote or restrict it. 

Inter-bundle microvoid is formed if the dual scale permeabilities are formed such that the resin flows faster inside the bundles along the fiber direction due to the capillary forces than in between them. Microvoids are entrapped between fiber bundles when it gets drawn due to the capillary action across a stitchi- as shown in Fig. 9.21. 

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