Fibre sources

It is important to model a correlation spectroscopy system, firstly to predict performance, and also to aid the very important choice of optical filter (or choose the best LED or super-luminescent optical fibre source to give the optimal spectral output), in order to achieve the best detection performance or best selectivity possible. The length of the cells and the pressure of gas (or gas concentration) are also important parameters (although all simulated results described below are based on use of lm long cells). 

One of the most debated environmental issues of the past fifteen to twenty years has been the exploitation of the forests for wood for paper making. Approximately 30% of the earth s land surface is forested, and around half of this is harvested commercially for industrial purposes (Chapter 1). Over 80% of this wood for industrial use comes from the forests of North America, Europe and what was formerly the Soviet Union. Wood has been the primary fibre source for pulp and paper production world-wide for many years, and it is necessary to take a global view of its consumption. Wood consumption world-wide has more than doubled since 1950 from 1.5 billion to 3.5 billion m3 (United Nations Food and Agricultural Organisation). Approximately half of this is used for fuelwood and half for industrial use. The principal driving force for this increase in consumption has been the increase in world population which shows a close correlation with wood consumption (Figure 10.1). 

Moore-Colyer, M.J.S., Hyslop, J.J., Longland, A.C. and Cuddeford, D. (1997a) Degradation of four dietary fibre sources by ponies as measured by the mobile bag technique. In Proceedings of the 15 Equine Nutrition and Physiology Symposium. Fort Worth, Texas, pp. 118-119. 

Inulin has no sweetness and possesses a bland taste. Physiologically, inulin behaves as a dietary fibre. At relatively high dose levels (15-40 g/day) it can have a prebiotic effect (i.e. it can selectively promote the growth of beneficial bacteria in the colon) and at high dose levels it may also have a laxative effect (Kolida el al., 2002). This is dependent on the specific composition of the product and the degree of polymerisation, which can vary. The caloric value for inulin is 1 kcal/g. Its use in soft drinks is as a fibre source, prebiotic and partial sugar replacer. 

Figure 5.11 Production (in metric tons) of some plant fibres. Source FAO (2004)...

There are broadly three types of operation carried out to produce paper and board products mechanical pulping, chemical pulping and re-cycled paper pulping. For mechanical pulping, the fibre source, commonly wood chips, is sheared at a temperature and pressure above the glass transition temperature of... 

In other studies, the effects of high-fibre diets on blood glucose levels were generally felt to be rather small (Simpson et al., 1981), and it was noted that postprandial blood glucose levels are influenced only when fibre content is fivefold higher than that of the normal British diet, whereby the effects of the dietary fibre source on carbohydrate metabolism seem to depend on the composition of the source. 

MDF is also produced from chips, but increasingly sawdust and shavings are used as fibre sources. As the name suggests the particles in this case are fibres or fibre bundles characterised by a high slenderness ratio, typically 80-100 1 for whole individual fibres. Most of the fibres in sawdust and shavings are damaged in the... 

The overall picture is of the wood-based panels sector continuing to grow as products are developed that meet new customer requirements. The processes have demonstrated an adaptability to different fibre sources, both in form and in species that has allowed plants to be established in most parts of the world, primarily to meet local demand, but also with a significant export component to those areas where fibre supplies are fully committed. 

Numerous parameters affect the extent of deposition. These parameters include factors like temperature, pH, closeness of the system, fibre source, age of wood. 

The content of organic material is a rather obvious parameter. If there is no depositable organic material there will be no deposit, and if the content of the material is high then deposition can be expected to be significant. The content of colloidal organic material is of course the result of many different factors, the most important ones being the fibre source, the treatment of the fibres and the extent of accumulation as a result of water recycling. By way of example, chemical fibres will contain considerably less colloidal material in comparison to mechanical fibres and waste paper. 

Silicate scales may be formed in pulp mills and in de-inking units, but are less common on paper machines. However, it is somewhat more common in recovery loops of pulp mills. It is a rather common scale in Asia, where content of silicate may be high in the fibre source, particularly bagasse. 

Mechanical separation of cellulose fibrils from natural fibre resources may involve the process of grinding to apply shear stress to the longitudinal axis of the fibres, so that the fibrillated fibres will have diameters ranging 20—90 nm (Taniguchi and Okamura, 1998). Ultrasonic extraction is another approach to disrupt the adhesion among the fibrils so as to extract nanofibrils from both cellulosic and protein fibre sources... 

Marek, J., Anonov, V., Bjelkova, M., Smirous, P., Fischer, H., Janosik, S., 2008. Enzymatic bioprocessing—new tool of extensive fibre source. In International Conference on Flax and Other Bast Plants, 21-23 July, Saskatoon, Canada. 

Fibre source World prodnction (metric tons)... 

FRCs can be classified based on matrix and fibres. Based on fibre source, FRCs may be natural fibre reinforced and synthetic fibre reinforced. Based on fibre length, they can be continuous fibre reinforced and discontinuous fibre reinforced. But FRCs are generally classified based on matrix component. Thus according to the types of matrices stated earlier, composites are of three types (i) ceramic matrix composites (CMCs), (ii) metal matrix composites (MMCs) and (iii) organic matrix composites (OMCs). Organic matrix is subdivided into two classes, namely polymer matrix and carbon matrix. A short description of all these types of composites are discussed below. 

Shinoj, S., R. Visvanathan, and S. Panigrahi, Towards industrial utilization of oil palm fibre Physical and dielectric characterization of Hnear low density polyethylene composites and comparison with other fibre sources. Biosyst. Eng.106, 378-388 (2010). 

T. Nishino, Natural fibre sources, in Green Composites Polymer Composites and the Environment, C. Baillie, (Ed.), pp. 49, Woodhead Publishing, England (2004). 

Effect of LTP plasma and UV-laser on polyester fibre. Source Courtesy of Wong etal., 2000.)... 

High performance fibres are usually mixed or interwoven in the fabrics, or used as layered fabric structures so as to have a combination of multiple protection functions in protective clothing. Most of those high performance fibres, except those converted from natural fibre sources, are stiff and do not have moisture management properties, and some of them have poor durability therefore, the fabrics made from them are frequently used together... 

Comparison of tensile properties of polyester and polypropylene fibres (Source-. From Reference 57.)... 

Coconut coir is the long fibre (15-35 cm) from the husk of the mature coconut and the average husk weighs 400 grams [7]. Coir is a fibre source for many cottage industries... 

A three-layer board having a corncob core and wood veneer face was produced for a short time in Czechoslovakia after World War II [9]. Corn stalks, like many agricultural fibre sources, consist of a pithy core with an outer layer of long fibres. Corn stalks and cobs are either hammer milled into particles or reduced to fibres in a pressurised refiner. 

Other important fibre sources include flax shaves, bamboo, papyrus, and reed stalks. There are two varieties of flax one is for fibre and the other is for linseed oil production. Bamboo is an important source of raw material for fibreboards in tropical countries. Most varieties of bamboo are fast-growing and produce strong fibres particleboards have also been made from bamboo. 

Figure 5.1 Injection port glass liner fitted to F 8c M Model 1609 gas chromatograph. The glass liner measures 60 mm x 40 mm od and 2 mm id and is very loosely packed with glass fibre. Source Author s own files)...

Pancreatic and intestinal enzyme activity in rats fed various fibre sources, jji "Fibre in Human and Animal Nutrition,"... 

Ye, W. and Broughton, R, Jr, Chicken Feather as a Fibre Source for Nonwoven Insulation , International Nonwovens Journal, Vol. 8, 1, 112-120, 1999. 

The context for mid-twentieth century research into alternative protein fibre sources... 

The impetus behind research into alternative fibre sources in the 1930s and 1940s was fuelled by the desire to produce economically viable wool-like fibres which could compete with, or complement, natural wool fibres. It is... 

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