Fiber developments

L. H. Smith, Sjnthetie Fiber Developments in Germany, Textile Research Institute, New York, 1946, pp. 534—541. 

H. Hupff, Sjnthetic Fiber Development in Germany, Part II, H. M. Stationery Office, London, U.K., 1945, p. 101. 

PAN fibers develop a structure with little point-to-point relationship between atoms in neighboring basal planes. This structure is labeled the turbostratic configuration and is characterized by interplanar spacing values greater than 0.344 nm. The crystallite size in the direction normal to the basal planes, or stack height (L, ), in turbostratic graphite is typically less than 5 nm. 

Acrylic fibers are a major synthetic fiber class developed about the same time as polyesters. Modacrylic fibers are copolymers containing between 35-85% acrylonitrile. Acrylic fibers contain at least 85% acrylonitrile. Orion is an acrylic fiber developed by DuPont in 1949 Dynel is a modacrylic fiber developed by Union Carbide in 1951. 

Another process for silicon carbide fibers, developed by Verbeek and Winter of Bayer AG [45], also is based on polymeric precursors which contain [SiCH2] units, although linear polysilmethylenes are not involved. The pyrolysis of tetramethylsilane at 700°C, with provision for recycling of unconverted (CHg Si and lower boiling products, gave a polycarbosilane resin, yellow to red-brown in color, which was soluble in aromatic and in chlorinated hydrocarbons. Such resins could be melt-spun but required a cure-step to render them infusible before they were pyrolyzed to ceramic... 

Fast-twitch muscle fibers develop tension two to three times faster than slow-twitch muscle fibers because of more rapid splitting of ATP by myosin ATPase. This enables the myosin crossbridges to cycle more rapidly Another factor influencing the speed of contraction involves the rate of removal of calcium from the cytoplasm. Muscle fibers remove Ca++ ions by pumping them back into the sarcoplasmic reticulum. Fast-twitch muscle fibers remove Ca++ ions more rapidly than slow-twitch muscle fibers, resulting in quicker twitches that are useful in fast precise movements. The contractions generated in slow-twitch muscle fibers may last up to 10 times longer than those of fast-twitch muscle fibers therefore, these twitches are useful in sustained, more powerful movements. 

Chlorex (2) A process for removing hydrogen chloride from hydrocarbons by aqueous alkaline extraction, using a bundle of hollow fibers. Developed by the Meridiem Company, Houston, TX and used in three installations in Japan in 1991. 

Liquicel A liquid-liquid extraction process in which the two liquids are separated by a permeable membrane in the form of hollow plastic fibers. Developed by Hoechst Celanese Corporation. 

As conclusion, bifunctional fibers having both phosphonic acid and sulfonic acid groups exhibit the characteristic metal ion selectivity and high breakthrough capacities in addition to the extremely fast adsorption rates. Studies on behavior of FPS-f in adsorption of other heavy metals like Fe(III) are now in progress. The bifunctional fiber developed in this work is attractive to application to the protection of the environment because of its extremely rapid adsorption rates and characteristic metal ion selectivity. 

In many applications, modification of PET fiber properties is desirable in order to enhance certain features of the product or to enhance the process of converting fibers into finished goods. In these cases, most of the basic PET fiber properties are acceptable but certain enhancements are desired, even at the expense of other properties or costs that will be affected by the modification. These side effects are always present it is the goal of fiber development personnel to engineer the best compromise. 

NAPFINING A process for removing naphthenic acids from petrolenm fractions by extracting with aqneons alkali, using a bnndle of hollow fibers. Developed by the Merichem Company, Honston, TX, and used in 19 plants in 1991. 

Further cellulosic structural variation is displayed by DP and crystallite size parameters. Aceiobacter and vascular plant primary wall celluloses are low in DP (2,000-6,000), while siphonocladalean and vascular plant secondary wall celluloses are relatively high in DP (> 10,000) (2). During cotton fiber development, the cellulose IV polymorph is produced during primary wall formation, while in secondary walls, cellulose I is observed... 

For nse in a detergent an enzyme mnst suffice the following criteria. In the first place it mnst have an adeqnate activity and stability at alkaline pH. It must also remain active and stable in a broad temperatme interval (e.g. 10-60°C). For domestic use the trend is to low temperatures (see 3.3.7 In-depth intermezzo). Additionally an enzyme should be resistant to hydrolysis and oxidation by other snbstances in the detergent, e.g. proteases. For enzymes with lanndry-softeiung properties two additional criteria apply, i.e. the enzyme must show a high fiber separation and at the same time not impair the fibers. Developments aim to further satisfy these criteria. 

Aluminum Oxide-Silicon Carbide Fiber, developed by the Carborundum Co at Niagara Falls, NY, will withstand temps of 2300°F. 

Yanagisawa, H., Davis, E. C., Starcher, B. C., Ouchi, T., Yanagisawa, M., Richardson, J. A., and Olson, E. N. (2002). Fibulin-5 is an elastin-binding protein essential for elastic fiber development in vivo. Nature 415, 168-171. 

J.R. Vest and K.M. Hamre, Effects of alcohol exposure during different periods of development Changes in hippocampal mossy fibers, Develop. Brain res., 17 (1985) 280-284. 

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