A method and system for controlling the engine during a return to idle maneuver when the engine’s oil is highly aerated. A tunable dispersion compensator 201 is constructed of first to fourth ring resonators 2021 to 2024 connected in series along a common linear waveguide 203. In some embodiments, the digital image data may be upsampled into expanded digital image data, which may improve the quality andor effectiveness of downstream image processing andor analysis. Further, each of the modules has a particular degree of functional programmability and the degrees of functional programmability monotonically vary in accordance with the sequence. The present disclosure further describes optimizations as pre-processing emphasis text, caching, dynamic transliteration rule pruning, and bufferingthrottling input. The improvement resides in contacting a titanium tetrachloride feedstock containing trace impurities of zirconium tetrachloride or hafnium tetrachloride with a sufficient amount of titanium hydride to convert any zirconium tetrachloride or hafnium tetrachloride to a lower volatile compound.