Fiber distribution

At the lowest level, the aetwork is the physical medium that connects the various pieces of equipmeat. This can be copper wire, often known as Ethernet, or optical fiber, ie, fiber-distributed data iaterface (EDDI). Networks allow transmission of data at nominal speeds of 10 to 100 megabits per second, depending on the physical medium used. 

Wu [353] who studied extruded fiber-filled composite samples established that the distribution of fibers along the radius of the specimen depended on the extrusion rate at low rates the fiber distribution is uniform, at medium rates the minimum of filler concentration occurs at 0.63 R (R is the extrudate radius) (in case of spherical particles this point corresponds to the maximum filler concentration) at high extrusion rates most of the fibers are concentrated about the flow axis and there are almost none on the extruded sample surfaces. 

Such a model makes it possible to calculate a change of fibers distribution along the length in the boundary layer. At present, practically the sole approach to the analysis of destruction when the fiber filler flows in the basic mass, outside the boundary layer, is an experimental determination of destruction kinetics for a given pair — fiber filler and polymer. Such dependencies can be obtained with the help of, say, rotary viscosimeters [47],... 

With nondestructive ultrasonic test back and forth scanning of a specimen is accomplished with ultrasonics. This NDT can be used to find voids, delaminations, defects in fiber distribution, etc. In ultrasonic testing the sound waves from a high frequency ultrasonic transducer are beamed into a material. Discontinuities in the material interrupt the sound beam and reflect the energy back to the transducer, providing data that can be used to detect and characterize flaws. It can locate internal flaws or structural discontinuities by the use of high frequency reflection or attenuation (ultrasonic beam). 

Of historical interest may be the use of a half dollar coin (the lighter weight 250 not as efficient). During the early 1940s the coin tap test was used very successfully in evaluating the performances of plastics, particularly RP primary aircraft structures. With a good ear (human hearing ear) there was (and is) a definite different sound between a satisfactory and unsatisfactory RP product. The unsatisfactory product would contain voids, delaminations, defects in fiber distribution, etc. In... 

Fiber optic cables are especially suited for high speed data transmission. The new FDDI ( Fiber Distributed Data Interconnect ) standard specifies a transmission rate of 100 Mbits/s. The comparison between the Ethernet and FDDI standards are given in Table 9.3. 

FDDI Fiber distributed data interface an optical fiber based interconnect. FLOPS Floating point operations per second. 

FDDI See fiber distributed data interface (FDDI). 

Sundler, F., Brodin, E., Ekblad, E. etal. (1985). Sensory nerve fibers Distribution of substance P, neurokinin A and calcitonin gene-related peptide. In Tachykinin Ant onists . (eds R, Hakason and F. Sundler). pp. 3-14, Elsevier Science, New York. 

In injection molded composites of polypropylene containing short glass fibers, the fiber orientation depended on the flow pattern (which, in turn, is related to mold thickness, the position of the gate, and flow rate)." Substantial variation was detected along the thickness of the sample. Crystallites followed a pattern of fiber distribution but they grew in a direction perpendicular to the direction of the fiber and specimen surface. The direction of spherulite growth was different in neat resin where crystallites grew parallel to the surface of the mold (specimen). 

Major results. Figure 14.9 shows the fiber distribution angle for samples of glass fiber filled polyamide subjected to different levels of strain. Micrographs (not included here) show that within this range of strains, fibers assumed orientations from the totally random (at e =0) to perfectly oriented (at e =2.75), which is very well reflected by the results of fiber orientation obtained from microradiographic studies. 

Figure 14.9. Fiber distribution at different strains. [Adapted, by permission, from Wagner A H Kalyon D M, Yazici R, Fiske T J, Antec 97. Conference proceedings, Toronto, April 1997, 996-1000 ]...

The complete stress-strain curve gives additional information about core properties. As noted previously, it may show something about fiber distribution, and additional knowledge about core properties may give us a chance to improve them. 

McLean JH, Shipley MT. 1987b. Serotonergic afferents to the rat olfactory bulb II. Changes in fiber distribution during development. J Neurosci 7 3029-3039. 

Fig. 85. A. Drawing displaying the distribution of mossy rosettes (dots) immunoreactive to monoclonal choline-acetyltransferase (ChAT) antibody. The section (40 fim thick) was cut sagittally through the middle vermis of rat cerebellum. A considerable number of immunoreactive mossy terminals are observed in lobules I through IXab, although they are much fewer than in lobules IXc and X. Calibration bar = 1 mm. B. Drawing of part of lobule IXab shows the overall distribution of immunoreactive fibers. Arrows indicate mossy fibers with glomerular rosettes. Small and large arrowheads point to some varicose fibers distributing in or near the Purkinje cell layer (PCL) and in the molecular layer (ML), respectively. The ML fibers are most frequently observed in this lobule and tend to be restricted to the inner half of the layer. Calibration bar = 200 jum. Ojima et al. (1989).

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