Fibers characteristics related

Textile finishing includes various efforts to improve the properties of textile fabrics, whether for apparel, home, or other end uses. In particular, these processes are directed toward modifying either the fiber characteristics themselves or the gross textile end properties. Such modifications may be chemical or mechanical in nature. One modification that is not covered in this article relates to the dyeing of textiles and the dyestuffs employed for fibers however, areas that involve chemical finishing designed to modify the normal dye receptivity and the growing use of enzyme treatments are included. 

The -3dB passband width, BW, for each wavelength channel tuned, is limited by the output fiber characteristics and the wavelengths coupled inside the core diameter (pwre- Taking this into account, and from (3), the following expression relates the bandwidth BW for every wavelength channel timed in the filter and the focal distance / of the lens according the optical power coupled into the output optical fiber (Parker et al., 1998) ... 

In this chapter we have chosen not to focus on specific examples of smart textiles application in order to avoid narrowing the field of smart implantable fibrous medical devices to a few innovative textile properties. Contrariwise, fiber characteristics are pointed out to show that all of them, in a prospective designing approach, could achieve smart features in the implantable device area. However, we are limited in exploratory areas using new materials because a decline is needed to be certain that a material is accepted by the body. Given the diversity of appreciation of smart appearance, as well as the implantable medical device aspect, we have focused on the biocompatibility and biointegration of substitutes in their environment. This theme therefore needs to be complemented by other approaches such as the concepts of smart attitude and implantable device as related in Fig. 13.1. 

Larzul, C., L. Lefaucheur, P. Ecolan, J. Gogue, A. Talmant, P. Sellier, P. Le Roy and G. Monin, 1997. Phenotypic and genetic parameters for longissimus muscle fiber characteristics in relation to growth, carcass, and meat quality traits in large white pigs. J. Anim. Sci. 75, 3126-3137. 

Wegner, J., E. Albrecht, 1. Fiedler, F. Teuscher, H.J. Papstein and K. Ender, 2000. Growth- and breed-related changes of muscle fiber characteristics in cattle. J. Anim. Sci. 78, 1485-1496. 

The ratio of stress to strain in the initial linear portion of the stress—strain curve indicates the abiUty of a material to resist deformation and return to its original form. This modulus of elasticity, or Young s modulus, is related to many of the mechanical performance characteristics of textile products. The modulus of elasticity can be affected by drawing, ie, elongating the fiber environment, ie, wet or dry, temperature or other procedures. Values for commercial acetate and triacetate fibers are generally in the 2.2—4.0 N/tex (25—45 gf/den) range. 

Stress—Strain Curve. Other than the necessity for adequate tensile strength to allow processibiUty and adequate finished fabric strength, the performance characteristics of many textile items are governed by properties of fibers measured at relatively low strains (up to 5% extension) and by the change ia these properties as a function of varyiag environmental conditions (48). Thus, the whole stress—strain behavior of fibers from 2ero to ultimate extension should be studied, and various parameters should be selected to identify characteristics that can be related to performance. 

Thermal Conductivity and Heat Capacity. Most fibers have similar thermal conductivities and heat capacities. The insulating characteristics of textiles are more related to fabric geometry than they are dependent on fiber thermal characteristics. 

The cellulose esters with the largest commercial consumption are cellulose acetate, including cellulose triacetate, cellulose acetate butyrate, and cellulose acetate propionate. Cellulose acetate is used in textile fibers, plastics, film, sheeting, and lacquers. The cellulose acetate used for photographic film base is almost exclusively triacetate some triacetate is also used for textile fibers because of its crystalline and heat-setting characteristics. The critical properties of cellulose acetate as related to appHcation are given in Table 10. 

Currently, HVI systems are providing rehable information on six characteristics of quaUty from a cotton sample in approximately 30 s that are highly related to the spinning quaUty and market value of the cotton. As of the 1991 crop year, cotton must be tested by HVI to be eligible for price supports in the United States. Information on every bale of cotton should gready improve the marketing of cotton and encourage the production of cotton with fiber properties desired by users. 

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... 

A representative measure of rubbery elasticity of a material may be two quantities dimensionless ratio (ct/t) and characteristic relaxation time 9 = ct/2ty. According to the data of works [37, 38] when fibers are introduced into a melt, ct/t increases (i.e. normal stresses grow faster than stresses) and 0 also increases on a large scale, by 102-103 times. However, discussing in this relation the papers published earlier, we noted in the paper cited that the data were published according to which if fibers were used as a filler (as in work [37]), 9 indeed increased [39], but if a filler represented disperse particles of the type Ti02 or CaC03, the value of 0 decreased [40],... 

Then, in this two-term unfolding model remains to define this exponent 2q, since all other quantities and especially the r-radius are either given, or evaluated from the thermodynamic equilibrium relations. Then, in this model the 2q-exponent is the characteristic parameter defining the quality of adhesion and therefore it may be called the adhesion coefficient. This exponent depends solely on the ratios of the main-phase moduli (Ef/Em), as well as on the ratio of the radii of the fiber and the mesophase. 

It is interesting that the stimulus compounds used in the study differ widely in their molecular structures, and yet they all interact with antibodies to thaumatin. It is, therefore, probable that a single receptor-structure responds to all sweet stimuli,there being a variation in the relative effectiveness of sweet stimuli across individual nerve-fibers, and the characteristics of all receptor sites do not appear to be identical. Earlier elec-trophysiological studies of single primary, afferent taste-neurons uniformly agreed that individual fibers very often have multiple sensitivities, and that individual, gustatory receptors are part of the receptive field of more than one afferent fiber. " We have yet to learn how these interact, and the nature of their excitatory, or possible inhibitory, relations, or both. 

The hair fibers derived from furry mammals are mainly made up (over 80%) of the structural protein keratin. The distinction between wool and hair is not compositional, but related to size wool fibers are generally fine and short, whereas those of hair are usually thicker and longer. The molecule of keratin consists essentially of a combination of amino acids about 18 amino acids make up the keratin molecule (see Textbox 67). The nature of the amino acids, their relative amounts, and their sequence and arrangement within the molecule of keratin vary from one animal species to another but are characteristic of any variety of wool or hair (Asquith 1977) (see Table 89). 

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