Texture convergent

The properties of mesophase pitch-based carbon fibers can vary significantly with fiber texture. Inspection of the cross-section of a circular mesophase fiber usually shows that the graphitic structure converges toward the center of the fiber. This radial texture develops when flow is fully developed during extrusion through the spinnerette. Endo [48] has shown that this texture of mesophase pitch-based carbon fibers is a direct reflection of their underlying molecular structure. 

Figure 6.4 TEM images of textured nickel electrodeposits [6.64]. (a) [211] texture (notice the parallel twin planes crossing the grains) (b) [110] texture (notice the five convergent twin planes).

It is very simple and vivid method [1]. One can observe characteristic streaks (Schlieren-textures) showing particular macroscopic defects, e.g., disclinatimis and establish the phase symmetry. In Fig. 4.1a the characteristic defects of the nematic phase (disclinations), are well seen. Fan-shape texture of the smectic C phase is shown in Fig. 4.1b. One can also distinguish between different types of uniform molecular orientation in different liquid crystal preparations using a cono-scopy technique (microscopic observations in the convergent light beam) in this case symmetry of the pattern corresponds to the texture symmetry. 

The design of the gating system for the component to be produced in the textured surface is very important since the merging flow fronts can cause surface defects on the moulded artefact. To avoid this fault, gates should be positioned to prevent converging streams of material. If this is not possible any converging lines should be directed into unseen areas of the moulding. 

The uniform stippled liver texture is interrupted by vessels which help define its segmental anatomy (Fig. 1.1) (CouiNAUD 1957). The hepatic veins, with their thin walls, appear as branching, tubular defects converging to the upper IVC. The portal tracts have strongly reflective walls from the associated... 

Divergent Textures and Convergent Textures (Figure 7). This texture is characterised by a wedge-shaped unit in which most of the lateral thickening or thinning is accomplished by thickening of individual reflections... 

Fig. 7. Divergent and convergent textures (a) divergent and (b) convergent (modified after Mitchum et al. [2]).

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