RESUMEN
Sugarcane straw fiber (SSF) samples were prepared by chemical pulping (CP) and steam explosion (STE). CP (5, 10, 15% NaOH + 0.2% w/w anthraquinone at 121 °C for 1 h) and STE pressure (1.77, 1.96, and 2.16 MPa at 220 °C for 4 min) SSF trays were molded with a hydraulic hot-press machine at 120 °C, 7 min, and 1.72 MPa. The yield (%) of SSF from STE (54-60% dry basis (db.)) was higher than CP (32-48% db.). STE trays had greater tensile strength than CP. However, STE's elongation and compression strength was lower than CP tray samples. The trays made from SSF using STE had less swelling in thickness, longer water wetting time, and a higher water contact angle than those made from CP. The micrographs displayed a smaller size of SSF obtained in STE than the CP. The appearance and area of peaks in ATR-FTIR spectra and XRD diffractograms, respectively, revealed that the STE trays had a larger residual lignin content from the lignin study and a lower crystallinity index than the CP trays. Moreover, the lightness values of the STE trays were lower than those of the CP trays due to lignin retention. The study results indicate that CP is the preferred method for producing SSF packaging material with high flexibility and fiber purity. However, when considering the specific SF of 4.28, the STE treatment showed superior physical and mechanical properties compared to CP. This suggests that STE could be an excellent alternative green pulping technique for producing durable biobased trays. Overall, the findings highlight the potential of STE as a viable option for obtaining trays with desirable characteristics, providing a sustainable and efficient approach to tray production.
RESUMEN
In engineering applications, flexible beam vibration control is an important issue. Although several researchers have discussed controlling beam vibration, there are few strategies for implementing it in actual applications. The passivity-based boundary control for suppressing flexible beam vibration was investigated in this paper. The controller was implemented using a moving base, and the beam model was an undamped shear beam. The control law was established using the storage function in the design technique. The finite-gain L2 - stability of the feedback control system was then proven. This method dealt directly with the PDE of the beam model with no model reduction. Because of the non-collocated measurement and actuation in many applications, the backstepping observer was required for state estimation. Since the controller was implemented at the end of the beam via a moving base, the beam domain remained intact. Therefore, the method is simple to apply in applications. With the use of the finite-difference approach, the PDEs were numerically solved. The controller's performance of the proposed control scheme was demonstrated using computer simulation.
RESUMEN
A lightweight amphibious aircraft hybrid composite wing was designed and optimized in this study. The Ansys Composite PrepPost and Ansys Mechanical Module use finite element modeling to simulate and assess the static structural test. It is possible to build a lightweight and cost-effective composite wing by balancing the amount and orientation of carbon fiber and glass fiber ply patterns. The BII2 wing design case (spar/rib/skin : ( ± 45 ) C , ( 0 / 90 ) C , . . . . 20 / ( ± 45 ) C , ( 0 / 90 ) G , ( ± 45 ) C , F ) S / ( ± 45 ) C , ( 0 / 90 ) G , F ) is the best option of 72 case studies, with a total weight of 45.46 kg and a manufacturing cost of 1,288 USD. The optimal design composite wing mock-up was built and tested on a universal test rig. The test demonstrated that the optimal wing design could withstand the maximum load (+6G and -3G) without structural collapse. The experimental structural deformation and elastic strain were consistent with the FEM model, within an acceptable error range.