Toray-2 International Fiber Journal August 22, 2019 348 Views Figure 2: Morphology and strength retention ratio of several super fibers after twisting at a twist factor of 80 (twist factor =T [turns/meter]/(10000/D [dtex])^0.5). Morphology and strength retention ratio of several super fibers after twisting at a twist factor of 80 (twist factor =T [turns/meter]/(10000/D [dtex])^0.5).