Single fibers

Fine adjusting and optimization of each step of this process is stiU underway, and a PVA fiber having a single fiber strength as high as 2 N/tex (21 gf/dtex), which is close to that of aramid fiber, has been reported (18). 

Resistance to axial compressive deformation is another interesting property of the silk fibers. Based on microscopic evaluations of knotted single fibers, no evidence of kink-band failure on the compressive side of a knot curve has been observed (33,35). Synthetic high performance fibers fail by this mode even at relatively low strain levels. This is a principal limitation of synthetic fibers in some stmctural appHcations. 

Methods for determining fiber-to-fiber friction have been developed (29—31). The friction coefficient can also be measured in terms of the force required to pull entwined fibers apart (32—34) or the force necessary to remove a single fiber from a mass of fibers under pressure (35). Another test involves an apparatus wherein one or a series of parallel fibers are mounted across a small bridge similar to a violin bridge. This is then pressed against a surface that may be another fiber or some other material, and the fibers alternately sHp and stick as they sHde across each other (36,37). 

Methods used for the tensile testing of single fibers and fibers taken from yams and tows are discussed in ASTM D3822 and D2101. Measurement equipment used in fiber tensile testing is described in ASTM D76. An overview of test procedures and their significance is also available (3,10). 

Table 5. Significance of Single-Fiber and Staple Characteristics in Wool Textile Processing ...

K Proportionality constant, for target efficiency of a single fiber in a bed of fibers Dimensionless Dimensionless ... 

It has been reported that the room temperature thermal conductivity of single fiber VGCF is 1950 W/mK [27]. Flowever, the room temperature thermal conductivity of VGCF mat may irot be comparable to that of single fibers. Since the thermal conductivity of VGCF mat has not been measui ed or determined, the following... 

In the single fiber pull out test (SFPO), a small portion of the fiber is embedded in the bulky matrix and the interfacial strength is calculated from the peak load when the fiber is pulled out of the composite. 

In this method [89], a single fiber is taken and partially embedded in a drop of uncured resin placed on a holder. The resin is then cured with the fiber held upright. The holder, with resin and fiber, is held in a grip attached to the crosshead and then pulled out from the resin. The force pulling the fiber out of the resin is balanced by shear stress at the resin-fiber interface holding the fiber in place. The maximum shear stress occurs as the embedded length tends to zero and is given by ... 

SAE 100R7 and 100R8 thermoplastic hoses. Nylon-covered single-fiber braid (left). 

Figure 3. Top panel Whole muscle force (x) and single fiber PCr (a, a) and ATP ( , ) concentrations at rest and after 10 and 20 sec of intermittent electrical stimulation at 50 Hz. Open symbols denote type I fibers closed symbols denote type II fibers. Bottom panel Glycogenolytic rates in type I and II fibers during the 20 sec stimulation period. The open bar denotes type I fibers the closed bar denotes type II fibers.

Allen, D.G., Lee, J.A., Westerblad, H. (1988). Intracellular calcium during fatigue in single fibers from Xenopus toe muscles. J. Physiol. 407, 75 (Abstract). 

Figure 3.31 Single fiber optic probe used for particle velocity measurement. (From Sekoguci et al., 1985. Copyright 1985 by American Society of Mechanical Engineers, New York. Reprinted with permission.)...

There are several works published on pH sensors based on energy transfer. Jordan and Walt developed a single-fiber optic sensor based on... 

Fuh M.R.S., Burgess L.W., Christian G.D., Single fiber-optic fluorescence enzyme-based sensor, Anal. Chem. 1988 60 433-435. 

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