Interfiber distance

The observed F depends on several variables, particularly the fiber numerical aperture, sample depth, interfiber distances, filter losses, and so fourth Similarly, an SNR figure of merit may be determined empirically, which would Incorporate SNR degradation due to fiber background. Equation (12.7) for is identical to Eq. (4.25), and both are based on experimetnally determined variables ... 

As the net current source propagates toward the tendon, an extracellular potential field arises and follows the action potential complex. At a given field point, this phenomenon is observed as a temporal potential waveform (Figure 25.4b) however, a more complete picture of the phenomenon is obtained by considering the spatial distribution of potentials in the cross section of the motor unit. Figure 25.5 shows schematically how the concentric isopotential lines of individual fibers overlap with those of other fibers in the same motor unit. In a typical healthy motor unit (Figure 14.5a), the mean interfiber distance... 

Interception. A particle approaching the fibers surface to a distance equal to or less than its radius (rparticie) or within the contact range of the fiber, without crossing a flow streamline tends to adhere to and deposit on the surface. It is an important mechanism for particles larger than about 100 nm, and its effectiveness depends on tbe ratio of particle diameter to the fiber diameter. If the interfiber distance or the porosity of the mat is smaller than the particle diameter dp, then a special case of interception or particle sieving oeeurs, but this is usually not an important mechanism in air or gas filtration. 

There are many studies on how to determine fiber dimensions, spacing, and reactor length however, commercially available units come in a relatively limited number of sizes, usually with inner liber diameters of 500 /rm or more. Several reports in the literature describe the use of hollow-flber systems in the development of a bioartiflcial pancreas, which place the islets on the shell side, while perfusing the fibers with the animal s plasma or blood. The fibers can be made relatively non-thrombogenic and of porosity sufficiently small as to avoid immune attack of the cells inside the shell. One difficulty with this configuration is that interfiber distances in the hollow-fiber device are not well controlled, so that regions within the shell space receive too little nutrients. 

It may be advantageous to place cells in the lumen of small fibers because the diffusional distance between the shell (where the nutrient supply would be) and the cells is essentially equal to the fiber diameter, which is easier to control than the interfiber distance. In one configuration, cells have been suspended in a collagen solution and injected into the lumen of fibers where the collagen is allowed to gel. Contraction of the collagen lattice by the cells even creates a void in the intraluminal space, which can be perfused with hormonal supplements, etc. to enhance... 

Interfiber distance Decrease =t> Increase reinforcement, and toughness Because of the confinement of crack propagation from fiber retardation... 

Another method developed at TRI for interfiber adhesion is a pull-out technique in which a fiber is displaced for a distance of 5 mm within a hair fiber bundle of well-defined packing density. The pull-out technique utilizes another attachment to the TRI/SCAN surface force analyzer. 

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