Optical fibers, manufacture

Alkoxide gels, 23 60 Alkoxide gels, in optical fiber manufacturing, 11 145 Alkoxide initiators, 14 259 Alkoxide ligands, thorium, 24 770 Alkoxides, 12 190 25 72-86 controlled hydrolysis of, 23 56 iron, 14 533 mixed-metal, 25 100 titanium, 25 82 uranium complexation with,... 

Overall heat-transfer coefficient, 13 244 Overall return rate (ORR), 9 545 Overbasing, 15 423 Overcladding, in optical fiber manufacturing, 11 144 Overcoat layers, in photography, 19 199 Overcuring, in tire compounding, 21 810 Overfeed/underfeed drums, 15 439-440 Overflow... 

Pratsinis, SE. and S.V.R. Mastrangelo Material Synthesis In Aerosol Reactors (Optical Fiber Manufacture), Chem. Eng. Progress 65 (May 1989). 

Several fiber coatings have been investigated. The most successful phase has been polydimethylsiloxane (PDMS), which is available commercially from several optical fiber manufacturers or from Supelco in thicknesses ranging from 7 to 100 pm (Arthur et al., 1992 Supelco Catalog, see Appendix). A second coating that is proving useful is a polyacrylate polymer for phenols and chlorinated phenols (Bucholz and Pawliszyn, 1993). 

Effluent remediation from wafer fabrication Recovery of germanium from optical fiber manufacturing effluents... 

Recovery of Germanium from Optical Fiber Manufacturing Effluents A-II.8.2... 

A-II.8.2 Recovery of Germanium from Optical Fiber Manufacturing Effluents (Based on the AIChE Student Contest Problem, January 1991)... 

Trimethylolpropane triacrylate (TMPTA) is a multifunctional acrylic monomer. It reacts with propylenei-mine to form polyfunctional aziridine. Sensitization was observed in a textile fabric printer. Patch tests were positive with the polyfunctional aziridine hardener, but were negative to TMPTA. TMPTA caused contact dermatitis in an optic-fiber manufacturing worker and was reported as a sensitizer in a floor top coat or in photopolymerizable inks. 

Steps 2 and 3. In these steps, the glass blank, the material that eventually will be drawn into fiber, is generated. It is here that the two major approaches to optical fiber manufacture first differ in a very significant way. 

Incorporation of OH is another critical aspect of the oxidation chemistry. Reduction to the ppb level is necessary for the manufacture of low loss optical fiber. Hydrogen is iacorporated iato the glass according to the reaction... 

The market for optical fiber worldwide in 1992 was 2.8 billion corresponding to 10 million fiber kilometers (Mfk) (38). This can be broken down into the U.S. market (3.7 Mfk), the rest of North America (0.4 Mfk), northern Europe (4.1 Mfk), eastern Europe (2.6 Mfk), the Pacific Rim (2.8 Mfk), and elsewhere (0.3 Mfk). Most of the optical fiber is manufactured by only a few companies, the largest of which are AT T and Coming. Other producers include Alcatel, Eujikura, Eurakawa, Northern Telecom, Pirelli, and Sumitomo. The market for optical fibers is projected to reach 3.5 biUion by 1998. In addition, according to ElectroniCast (San Mateo, Ca.), the total market for passive optical components, optical electronics, connectors, and fiber-optic cable is predicted to increase from 1.76 billion (U.S.) in 1992 to over 4 billion in 1997, and 10 billion by 2002. 

Relatively smaller amounts of very high purity A1F. are used ia ultra low loss optical fiber—duotide glass compositions, the most common of which is ZBLAN containing tirconium, barium, lanthanum, aluminum, and sodium (see Fiber optics). High purity A1F. is also used ia the manufacture of aluminum siUcate fiber and ia ceramics for electrical resistors (see Ceramics AS electrical materials Refractory fibers). 

TaF has been characterized by ir, Raman, x-ray diffraction, and mass spectrometry (3,11,12). TaF has been used as a superacid catalyst for the conversion of CH to gasoline-range hydrocarbons (qv) (12) in the manufacture of fluoride glass and fluoride glass optical fiber preforms (13), and incorporated in semiconductor devices (14). TaF is also a catalyst for the Hquid-phase addition of HF to polychlorinated ethenes (15). The chemistry of TaF has been reviewed (1,16—19). Total commercial production for TaF is thought to be no more than a few hundred kilograms aimuaHy. 

Optics. Good optical properties and low thermal resistance make poly(methyl methacrylate) polymers well suited for use as plastic optical fibers. The manufacturing methods and optical properties of the fibers have been reviewed (124) (see Fiber optics). Methods for the preparation of Fresnel lenses and a Fresnel lens film have been reported (125,126). Compositions and methods for the industrial production of cast plastic eyeglass lenses are available (127). 

Most Kaminsky catalysts contain only one type of active center. They produce ethylene—a-olefin copolymers with uniform compositional distributions and quite narrow MWDs which, at their limit, can be characterized by M.Jratios of about 2.0 and MFR of about 15. These features of the catalysts determine their first appHcations in the specialty resin area, to be used in the synthesis of either uniformly branched VLDPE resins or completely amorphous PE plastomers. Kaminsky catalysts have been gradually replacing Ziegler catalysts in the manufacture of certain commodity LLDPE products. They also faciUtate the copolymerization of ethylene with cycHc dienes such as cyclopentene and norhornene (33,34). These copolymers are compositionaHy uniform and can be used as LLDPE resins with special properties. Ethylene—norhornene copolymers are resistant to chemicals and heat, have high glass transitions, and very high transparency which makes them suitable for polymer optical fibers (34). 

Article of Manufacture. An article of manufacture is an iavention such as a two-headed tooth bmsh, an iatravenous fluid bag, or an optical fiber "made" by a machine. One example of an iavention which could be considered an article of manufacture is U.S. Patent No. 5,241,990 tided "Irrigation/Aspiration Valve and Probe for Laparoscopy" (2). 

The medium used for the transmission of information and data over distances has evolved from copper wire to optical fiber. It is quite likely that no wire-based information transmission systems will be installed in the future. The manufacture of optical fibers, like that of microcircuits, is almost entirely a chemical process. 

There are four principal processes that may be used to manufacture the glass body that is drawn into today s optical fiber. "Outside" processes—outside vapor-phase oxidation and vertical axial deposition— produce layered deposits, of doped silica by varying the concentration of SiCl4 and dopants passing through a torch. The resulting "soot" of doped silica is deposited and partially sintered to form a porous silica boule. Next, the boule is sintered to a pore-free glass rod of exquisite purity and transparency. 

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