Filaments technology

Orofino, T. A. (1970). Development of hollow filament technology for reverse osmosis desalination systems. Report No. 549. U.S. Office Saline Water Res. Develop. Progr. 

Staple and Tow. The same extmsion technology that produces continuous filament yam also produces staple and tow. The principal difference is that spinnerets with more holes are used, and instead of winding the output of each spinneret on an individual package, the filaments from a number of spinnerets are gathered together into a ribbon-like strand, or tow. A mechanical device uniformly plaits the tow into a carton from which it can be continuously withdrawn without tangling. 

Slit-Film Fiber. A substantial volume of olefin fiber is produced by slit-film or film-to-fiber technology (29). For producing filaments with high linear density, above 0.7 tex (6.6 den), the production economics ate more favorable than monofilament spinning (29). The fibers are used primarily for carpet backing and rope or cordage appHcations. The processes used to make slit-film fibers are versatile and economical. 

Asahi Chemical Industries (ACl, Japan) are now the leading producers of cuprammonium rayon. In 1990 they made 28,000 t/yr of filament and spunbond nonwoven from cotton ceUulose (65). Their continuing success with a process which has suffered intense competition from the cheaper viscose and synthetic fibers owes much to their developments of high speed spinning technology and of efficient copper recovery systems. Bemberg SpA in Italy, the only other producer of cuprammonium textile fibers, was making about 2000 t of filament yam in 1990. 

Textile technology is used to mechanically or aerodynamicaHy arrange textile fibers into preferentially oriented webs. Fabrics produced by these systems are referred to as dry-laid nonwovens. Dry-laid nonwovens are manufactured with machinery associated with staple fiber processing, such as cards and gametts, which are designed to manipulate preformed fibers in the dry state. Also included in this category are nonwovens made from filaments in the form of tow, and fabrics composed of staple fibers and stitching filaments or yams, ie, stitchbonded nonwovens. 

Bicomponent technology has been used to introduce functional and novelty effects other than stretch to nylon fibers. For instance, antistatic yams are made by spinning a conductive carbon-black polymer dispersion as a core with a sheath of nylon (188) and as a side-by-side configuration (189). At 0.1—1.0% implants, these conductive filaments give durable static resistance to nylon carpets without interfering with dye coloration. Conductive materials such as carbon black or metals as a sheath around a core of nylon interfere with color, especially light shades. 

Vacuum Tubes. In the manufacture of vacuum tubes for use in polarized ion sources, vaporized cesium is used as a getter for residual gaseous impurities in the tube and as a coating to reduce the work function of the tungsten filaments or cathodes of the tube. The cesium vapor is generated by firing, at about 850°C within the sealed and evacuated tube, a cesium chromate pellet and zirconium (12) (see Vacuum technology). 

There are, however, technical limitations to substitution. Some materials are used in ways not easily filled by others. Platinum as a catalyst, liquid helium as a refrigerant, and silver on electrical contact areas cannot be replaced they perform a unique function - they are, so to speak, the vitamins of engineering materials. Others - a replacement for tungsten for lamp filaments, for example - would require the development of a whole new technology, and this can take many years. Finally,... 

A large number of CVD diamond deposition technologies have emerged these can be broadly classified as thermal methods (e.g., hot filament methods) and plasma methods (direct current, radio frequency, and microwave) [79]. Film deposition rates range from less than 0.1 pm-h to 1 mm-h depending upon the method used. The following are essential features of all methods. 

Hence, the main aim of the technological process in obtaining fibres from flexible-chain polymers is to extend flexible-chain molecules and to fix their oriented state by subsequent crystallization. The filaments obtained by this method exhibit a fibrillar structure and high tenacity, because the structure of the filament is similar to that of fibres prepared from rigid-chain polymers (for a detailed thermodynamic treatment of orientation processes in polymer solutions and the thermokinetic analysis of jet-fibre transition in longitudinal solution flow see monograph3. ... 

Pectin degradation requires fee combined action of various enzymatic activities. However, evaluation of fee contribution of individual pectinases in Suit juice extraction and clarification is rather complicated. Most commercial pectinolytic enzyme preparations are produced by fermentation wife filamentous fungi, mostly strains belonging to fee genus Aspergillus,. plication studies with mixtures of isolat enzymes obtained by fermentation or by means of fractionation of commercial enzyme preparations can be used to assess the importance of fee various individual enzymes. Subsequently, molecular biology and fermentation technology can be used to enhance specific desirable enzymatic activities. 

A fine wire or thread. In textile technology the fine thread formed at the spinnerettes in the manufacture of synthetic and man-made fibres. See Continuous Filament. 

Anderson JG (1975) Immobilized cell and film reactor system for filamentous fungi. In Smith JE, Berry DR, Kristiansen B (eds) Fungal technology. The filamentous fungi. Edward Arnold, London, pp 146—170... 

Activation of the surface by fluorination for adhesion with the reinforcement resin27 This is a cost-effective mass production technology, which does not interfere with the overwrapping production processes, e.g., filament winding (see Figure 16.5). 

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