Fiber content measurement

Techniques for efficiently and economically measuring the other important characteristics, ie, length, strength, and position of weakness in the fiber, are now in commercial use. Existing color-measuring equipment can be used to measure the color (whiteness or yellowness) of washed wool, but accurate measuring of colored-fiber content remains a problem (5,8). 

The overall objective of research under way as of ca 1997 is to develop a system of sale by description for fine and medium wools whereby the buyer is presented only with measured data on the principal characteristics of the raw wool, as well as an assessment of the less important characteristics by an independent skilled appraiser (8). A scheme for assessing the risk of the presence of colored fiber content in greasy wool has been proposed which depends on production parameters and on the age and sex of the sheep (5). Instmmentation and computer algorithms for the measurement of style and handle... 

Glass fiber diameter can also affect the physical properties. In general, fiber diameters from 6-17. im have been used in PBT, with the narrower fibers giving slightly better properties. However, fiber length distribution and fiber content may play a more important role than diameter [32], Fiber content in a PBT composite is often measured by specific gravity and by ash content. Both of these measurements need to be corrected in cases where the blend is pigmented or combined with other materials. 

Fig. 2.18 illustrates the nature of the intensity profiles in pure polyetheretherke-tone (PEEK) and carbon fiber reinforced PEEK composites in the transmission and reflection modes, respectively. The quenched amorphous and slowly cooled crystalline components from PEEK can be separated. The three prominent diffraction peaks from the crystalline components in Fig. 2.18(a) correspond to the three uniform rings which can be detected in X-ray photographs. In contrast, no clearly measurable signal is identified from the PEEK amorphous phase independent of the carbon fiber content. 

As with tensile properties, both compressive strength and modulus depend on the fiber content and hber orientation (see Table 5.8). The interlaminar shear strength reported in Table 5.8 is a measure of the shear strength in the thickness direction of the SMC sheet. It is determined by three-point flexural testing of beams with short span-to-depth ratios and is considered to be a quality-control test for molded composites. 

For high fiber content, one can approximate the thermal conductivity of the composite by the thermal conductivity of the fiber. The thermal conductivity can be measured using the standard tests ASTM Cl 77 andDIN 52612. A new method currently being balloted (ASTM D20.30) is preferred by most people today. 

Measurement of parameters which cannot be related to SI, such as fat and fiber content of food and pH can be made traceable to other references according to the same principles as discussed above. 

As mentioned earlier, the starting materials are of high purity. Because we work in a closed system and because we have an electrodeless discharge there should be no sources of additional impurities. Neutron activation analysis revealed that all the transition metal impurities that strongly affect the transmission properties of the optical fibers are lower than 1 ppm. From fiber transmission measurements we know that, besides traces of OH, some impurities must be lower than 1 ppb because only the intrinsic attenuation of the material is found. The chlorine content is rather large at 0.1%, even at the deposition temperature of 1000 °C. Fortunately the chlorine does not affect the optical properties in the interesting region of 0.6 pm - 1.5 pm. 

In addition to the effect of the amount of fiber content also a dependence on the type of the used fiber can be observed in a different example (Fig. 8, [26]). In this investigation it was possible to carry out the wave-scan measurements directly on the unpainted surfaces. 

Theoretical values of the effective thermal conductivity of polyester fabrics (6J (estimated by an expression developed for fibers placed in parallel with each other surrounded by a known amount of air and vice versa) agreed well with line heat source measurements of the thermal conductivity of fabrics varying in thickness, construction, and fiber content (7.). These results also indicate that the thermal conductivity of fabrics in directions parallel to the surface is greater than that perpendicular to the surface, especially for filament yarn the thermal conductivity of woven fabrics in directions parallel to the warp yarns, which were arranged more closely, was greater than in directions parallel to the filling yarns (7.) ... 

The standard log length used in the Northeast is 48 in., whereas 63 in. is common in the South. Wood generally is measured by log volume, a standard cord being considered to contain 128 ft3. Large timber on the West Coast generally is measured in board feet of solid volume. Measurement and purchase of wood on a weight basis are practiced, and are desirable because weight is directly related to fiber content.1... 

Experimental investigations were performed with fiber-reinforced RubCon samples measuring 4 x 4 x 16 cm. Various fiber materials were used steel, polypropylene, rough basalt, and glass. The reinforcement ratio for appropriate fiber materials was adopted according to publicized research [4,11]. The optimal volume of fiber content is 1.0%-1.5% for steel fibers and 1.0-5.0% for glass fibers. 

Wang and Johnson (2001) reported on test measurement methods that were major indicators of soybean oil quality. These tests included peroxide value, anisidine value, FFA content, phospholipid content, total tocopherol content, oxidative stability index, color, and moisture content. For soybean meal, they reported on urease activity, protein dispersibility index (PDI), rumen bypass or rumen undegradable protein, trypsin inhibitor activity, moisture content, residual oil content, protein content, fiber content, color, amino acid profiles, and protein solubility under alkaline (KOH) conditions. 

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