Fiber, scattering

If these concepts of curve analysis shall be applied to the anisotropic scattering of polymer fibers, one should choose to study either the longitudinal or the transversal density fluctuations. According to the decision made, the fiber scattering must be projected either on the fiber axis or on the cross-sectional plane. This results in scattering curves with a one- or a two-dimensional Porod s law. Because modern radiation sources always feature a point-focus, the required plots for the separation of fluctuation and transition zone are readily established (cf. Table 8.3). 

Figure 8.31. Fiber scattering of PEE 1000/43 (a) at an elongation = 0.88 (b) during relaxation from = 0.88. The fiber direction is indicated by a double-arrow. Visualized region —0.15nm 1 < s 2, sj < 0.15nm 1. = (l l,) /Iq, with Iq and / defined by the initial and the actual distance between two fiducial marks on the sample...

Transformation of the Pre-evaluated Image. The image /( i2, 3) is projected on the representative plane (iijft) of the fiber scattering ... 

Lischer and Louge (1992) described an optic fiber probe that measured the particle volume fraction in a dense suspension using light from a 5 mW He-Ne laser. Particles illuminated by the central fiber scattered light to the surrounding fibers connected to a photodiode. The output was calibrated against a capacitance probe. Figure 4-17 is a schematic of the calibration set... 

Rathbone et al. (1989) used a similar probe to determine particle velocity parallel to the surface. The difference is that the central fiber is the sensor of the Fiber Optic Doppler Anemometry (FODA), and it transmits light from a 5 mW He-Ne laser. Particles illuminated by the central fiber scatter light to the surrounding fibers as they passed the probe. When the particles passed over two fibers in succession, the transit time at cross correlation maximum can be obtained. In principle, by correlating the strongest signals from the fibers, it should be possible to determine the direction or different components of particle velocity. However, the measurement was carried out in a two-dimensional fluidized bed, and relatively few data were obtained. 

Carbon fibers scatter both x-rays and electrons, and the corresponding diffraction patterns can be used to assess structural parameters [4] [31]. The diffraction patterns of carbon fibers contain a limited number of reflections, i.e., usually a strong 002 reflection and (when present) weaker 004,10 and 11 reflections, due to the turbostractic character of the carbon. The OOl and hk reflections become less dif se as the heat treatment temperature (HTT) is increased. Finally, the separation of the 10 reflection into its 100 and 101 components and the appearance of the 112 reflection are observed only for true graphite fibers, prepared from mesopitch fibers and formed at 3000 C. 

X-ray Scattering from Oriented Liquid Crystalline Polymers— Fiber Scattering... 

Figure 5.18 X-ray fiber scattering pattern from oriented polymer sample. The chemical structure of the polymer is shown in Figure 5.19 with x = 0.4ra y = 0.6n.

Figure 5.19 Chemical strucmre of polymers in fiber scattering study.

Figure 5.20 X-ray fiber scattering pattern from oriented polymer sample. The chemical structure... 

Analytical work has been published on the optical behavior of composite materials. Edwards et al. (1962) analyzed the spectral reflectance and transmittance of imperfectly diffuse samples in an integrating sphere and provided calculations of the measurement error resulting from the nonideal material. Scattering in composites has been predicted in recent works by Varadan (1991), White et al, and Lee et al. Individually, each fiber scatters the incident radiation in a forward-facing cone centered around the incident direction. 

The information content of most of these projections was already described in this chapter, except for the representative fiber scattering,... 

Figure 8.12 (a) Schematic representation of the spectroscopic analysis of gold nanorods in a mouse. The anesthetized mouse was placed on a port of an integrating sphere monochromatic light from a spectrophotometer was then introduced into the mouse abdomen through optical fibers. Scattered light from the mouse abdomen was... 

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