Effect of zinc oxide surface treatment concentration and nanofiller loading on the flexural properties of unsaturated polyester/kenaf nanocomposites.

Due to environmental concerns and budgetary constraints associated with synthetic fibers, natural fibers (NFr) are becoming increasingly popular as reinforcement in polymer composites (PCs) for structural components and construction materials. The surface treatment (ST) method is a well-established technique for enhancing the strength of interfacial bonding between NFr and the polymer matrix (PM). As a result, this research aims to determine the effect of ST with zinc oxide nanoparticles (ZnONPs) on the flexural properties of unsaturated polyester (UPE)/kenaf fiber (KF) nanocomposites. The hand lay-up technique was employed to produce KF-reinforced unsaturated polyester composites (KF/UPE) for this investigation. UPE/KF-ZnONPs composites were made with varying NFr loadings (weight percent), ranging from 10 to 40%. KF was treated with five distinct amounts of ZnONPs (from 1 to 5% weight percent). According to the findings of the investigation, the composite samples incorporating ZnONPs displayed superior optimum flexural properties compared to the untreated KF composite. It was found that 2% ZnONPs was optimal, and ST with ZnONPs could produce robust KF with improved flexural properties.

A New Nonlinear Dynamic Speed Controller for a Differential Drive Mobile Robot.

A disturbance/uncertainty estimation and disturbance rejection technique are proposed in this work and verified on a ground two-wheel differential drive mobile robot (DDMR) in the presence of a mismatched disturbance. The offered scheme is the an improved active disturbance rejection control (IADRC) approach-based enhanced dynamic speed controller. To efficiently eliminate the effect produced by the system uncertainties and external torque disturbance on both wheels, the IADRC is adopted, whereby all the torque disturbances and DDMR parameter uncertainties are conglomerated altogether and considered a generalized disturbance. This generalized disturbance is observed and cancelled by a novel nonlinear sliding mode extended state observer (NSMESO) in real-time. Through numerical simulations, various performance indices are measured, with a reduction of 86% and 97% in the ITAE index for the right and left wheels, respectively. Finally, these indices validate the efficacy of the proposed dynamic speed controller by almost damping the chattering phenomena and supplying a high insusceptibility in the closed-loop system against torque disturbance.