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The paper aims to present an innovative method for identification of flight modes in the spin maneuver, which is highly nonlinear and coupled dynamic.

To fix the mode mixing problem which is mostly happen in the EMD algorithm, the authors focused on the proposal of an optimized ensemble empirical mode decomposition (OEEMD) algorithm for processing of the flight complex signals that originate from FDR. There are two improvements with the OEEMD respect to the EEMD. First, this algorithm is able to make a precise reconstruction of the original signal. The second improvement is that the OEEMD performs the task of signal decomposition with fewer iterations and so with less complexity order rather than the competitor approaches.

By applying the OEEMD algorithm to the spin flight parameter signals, flight modes extracted, then with using systematic technique, flight modes characteristics are obtained. The results indicate that there are some non-standard modes in the nonlinear region due to couplings between the longitudinal and lateral motions.

Application of the proposed method to the spin flight test data may result accurate identification of nonlinear dynamics with high coupling in this regime.

First, to fix the mode mixing problem in EMD, an optimized ensemble empirical mode decomposition algorithm is introduced, which disturbed the original signal with a sort of white Gaussian noise, and by using white noise statistical characteristics the OEEMD fix the mode mixing problem with high precision and fewer calculations. Second, by applying the OEEMD to the flight output signals and with using the systematic method, flight mode characteristics which is very important in the simulation and controller designing are obtained.

This paper aims to extracted sericin from the cocoons of Bombyx mori silkworms, and sericin powder was applied onto drawn textured polyethylene terephthalate (PET) yarns as a spin finish. The reactivity on the surface of PET yarns was analyzed through Fourier transform infrared spectrophotometry–attenuated total reflectance (FTIR-ATR) and dyeing with methylene blue as a reactive dye. Also, investigations were conducted on the effects of sericin, citrc acid (CA) (as a crosslinking agent), and sodium hypophosphite (as a catalyst) concentrations on some properties of false-twist textured PET yarns.

A false-twist texturing machine (Scragg-Shirley minibulk, England) was used with the draw ratio of 1.05, heating temperature of 120°C, texturing speed of 100 m min⁻¹ and applied twist of 3,000 TPM. The aqueous extraction of sericin was carried out by the boiling of the raw silk in distilled water with L:R: 40:1 for 120 min. The aqueous solution was filtered with a filter paper to remove the impurities and insoluble fibroin. Finally, the sericin solution was freeze-dried to obtain the sericin powder. The sericin solution was applied on the drawn textured PET yarns using the “pad-dry-cure” method.

Sericin fixation onto the PET yarns was confirmed by FTIR-ATR. The results showed that there were no significant changes in the tensile strength, linear density, crimp contraction and crimp modulus, elongation at break and shrinkage. In contrast, a substantial increase was observed in moisture regain, vertical wicking, dye uptake and ultraviolet protection. There was also a reduction just in the electrical resistivity, in the presence of sericin.

Although sericin has been known to have numerous beneficial properties, its application in textile industry as a spin finish has not been reported yet.