Development of Texture

Here we examine models that try to explain how textures develop during deposition on oriented (single crystal), textured, polycrystalline, and amorphous substrates. We select electrodeposition of nickel as a model system. 

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To date, there has been relatively little work reported on the mesophase pitch rheology which takes into account its liquid crystalline nature. However, several researchers have performed classical viscometric studies on pitch samples during and after their transformation to mesophase. While these results provide no information pertaining to the development of texture in mesophase pitch-based carbon fibers, this information is of empirical value in comparing pitches and predicting their spinnability, as well as predicting the approximate temperature at which an untested pitch may be melt-spun. 

The parallelization of crystallites, occurring as a result of fiber drawing, which consists in assuming by crystallite axes-positions more or less mutually parallel, leads to the development of texture within the fiber. In the case of PET fibers, this is a specific texture, different from that of other kinds of chemical fibers. It is called axial-tilted texture. The occurrence of such a texture is proved by the displacement of x-ray reflexes of paratropic lattice planes in relation to the equator of the texture dif-fractogram and by the deviation from the rectilinear arrangement of oblique diffraction planes. With the preservation of the principle of rotational symmetry, the inclination of all the crystallites axes in relation to the fiber axis is a characteristic of such a type of texture. The angle formed by the axes of particular crystallites (the translation direction of space lattice [c]) and the... 

In Chapter 7 various growth models were described layer growth (Section 7.9), nucleation-coalescence growth (Section 7.10), development of texture (Section 7.11), columnar microstructure (Section 7.12), and other structural forms (Section 7.13). In this section we discuss the effects of additives on these growth mechanisms. 

Microscopic structure of texturized water-extracted soy flour and texturized soy concentrate were quite similar to that of texturized soy flour. Scanning electron microgrpahs showed that water extraction of soy flours had little effect on morphological characteristics of texturized soy products (Figure 10). Solubility of soluble sugars was not affected by texturization, whereas solubility of proteins decreased sharply when soy flour was texturized (Table VII). It appears that soluble sugars did not interact with proteins during texturization. Based upon results of microscopy and solubility studies, it is reasonable to speculate that natural soluble carbohydrates are not required (do not play an important role) in development of texture or stabilization of structure. 

Milk fat plays a very important role in the development of texture in cheese. Reduced-fat cheeses tend to be firmer and more elastic than cheeses with a higher fat content. Undoubtedly the presence of a more dense protein matrix results in a firmer cheese. The precise role of fat in cheese texture is not well understood, since problems of increased firmness can be partially overcome by increasing the MNFS. Studies by Green et al (1981) on the texture of cheeses made from concentrated milk suggest a possible role of fat in cheese firmness. Reduced fat in the curd would result in a smaller fat-protein interfacial area and an increased separation between fat globules. The capacity of the fat and protein phases of cheese to move in relation to each other would be reduced and would consequently result in a firmer cheese. 

Green, M. L. and Manning, D. J. 1982. Development of texture and flavor in cheese and other fermented products. J. Dairy Res. 49, 737-748. 

As with many things in the field of materials processing, development of texture is often a trade-off. Some properties are enhanced whereas others deteriorate when a strong texture is present. In the descriptions of materials processing techniques in the following sections, mechanisms for texture formation are introduced. Development of both type and degree of texture is one the factors that influence a material scientist s choice of processing route. 

On the macroscopic level reaction and catalyst systems have been defined and process considerations determine the role of further catalyst development. Catalyst research has contributed to the development of texture determination techniques... 

Sabol, S.M. 1994. Development of textured and tabular grain microstructure in alumina fibers via seeded sol-gel processing. Ph.D. diss., Pennsylvania State University. 

Hong SH, Messing GL (1999) Development of textured mullite by templated grain growth. J Am Ceram Soc 82 867-872... 

Tolstoguzov, V.B. (1991) Development of texture in meat products through thermodynamic incompatibility. In Developments in Meat Science, Vol. 5. (ed. Lawrie, R.A.). Elsevier, London, pp. 159-189. 

Bellare A, Cohen R E and Argon A S (1993) Development of texture in poly(ethylene terephthalate) by plane-strain compresaon, Polymer 34 1393-1403. 

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