![]() ![]() Its goal is to enable rapid, low-cost and agile manufacturing of small, complex-shaped composite parts and increase composites’ ability to compete against machined aluminum in defense applications. RAPM is the “forming” part of The Tailorable Feedstock and Forming (TFF) program launched by the Defense Advanced Research Projects Agency (DARPA, Arlington, Va., U.S.) in 2015. Solvay Composite Materials (Alpharetta, Ga., U.S.) was a key partner in the RApid high-Performance Manufacturing (RAPM) program led by The Boeing Co. For smaller aerostructures especially, prepreg press molding offers the potential for takt times of <30 minutes while still achieving high-quality, complex geometry parts. al., SAMPE 2019.Ĭombining press molding and prepreg not only delivers an efficient, high-rate process with the performance and easy handling of prepreg, it also avoids some of the complex process dynamics of filling dry reinforcements with liquid resin during processes such as resin infusion and resin transfer molding (RTM). Slide 8 “Rapid High Performance Molding of Structural 圎P-2750 Prepreg for Compression Molding” by Timothy J. After the liquid reactant has cleared the system, flow of the evaporative liquid is terminated and the burner assembly flame turned off.SOURCE | Boeing, DARPA, Solvay. Once the desired quantity of soot has been formed, the liquid reactant is transitioned back to the evaporative liquid while maintaining steady state flow. The liquid reactant is delivered along the same path to the burner assembly, which discharges the liquid reactant into the combustion zone as an atomized liquid to form soot used in the manufacture of glass. Once steady state liquid flow has been achieved in the system, the evaporative liquid is transitioned to the liquid reactant. Due to the tendency of liquid reactants to react to form solids when exposed to water in the air, an evaporative liquid is first delivered through the burner assembly to the combustion zone. The drive-in step is conveniently combined with the sintering or consolidation step to further enhance the efficiency of the doping process.Ībstract: The present invention is directed to a system and method for delivering liquid reactants through a burner assembly to form soot used in the manufacture of glass, and in particular, optical waveguides. In the incremental doping process the doping step is separated into a deposit step, where “excess” fluorine is deposited on the silica particles, and a drive-in step where atomic fluorine is distributed into the silica particles. The process time required may be reduced by using incremental fluorine doping. This inherent property allows the entire core rod to be heated prior to fluorine doping resulting in selective partial consolidation and preventing fluorine doping of the doped center core region. Due to dopants in the core region, the soot in the core region consolidates before the soot in the outer undoped region. When a 50 percent substitution of oxygen -18 for oxygen-16 is made in the core region of the fiber, the Raman gain spectrum is substantially broadened.Ībstract: The doped silica core region of a core rod for an optical fiber preform is protected against unwanted fluorine doping during fluorine doping of the outer silica layer by selectively consolidating the core region prior to fluorine doping. The fiber may be easily manufactured with conventional fiber manufacturing equipment by way of a plasma chemical vapor deposition technique. The resulting isotopically-altered fiber has a minimum loss of 0.044 dB/km less than conventional fiber, and a bandwidth that is 17 percent broader for a loss range between 0.044-0.034 dB/km. ![]() In one embodiment, oxygen-18 is substituted for the much more naturally abundant oxygen-16 at least in the core region of the fiber. ![]() A heavier, less naturally abundant isotope of silicon or oxygen is substituted for a lighter, more naturally abundant isotope to shift the infrared absorption to a slightly longer wavelength. Abstract: An isotopically-altered, silica based optical fiber is provided having lower losses, broader bandwidth, and broader Raman gain spectrum characteristics than conventional silica-based fiber. ![]()
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