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This paper proposes a novel piezoelectric energy harvester attached with a trailing-edge flap under various installation angles, for enhancing the aeroelastic vibration and improving the harvesting performance. The mathematical models of the fluid-structure-electric coupled fields are derived, the simulation models of the multi-physical coupled fields of the harvester system with various installation angle flaps are established, and the experimental prototypes of the harvester are fabricated. The influences of the flap installation angles on the flow field and output characteristics are investigated theoretically, numerically, and experimentally. The results demonstrate that the flap stiffness and damping coefficients exert less influence on vibration characteristics and harvesting performance. The flap at a certain installation angle alters the flow field, affects the flow pattern, restricts the vortex shedding, and offsets the aerodynamic force and moment. A decrease in the flap installation angles results in increasing the vibration response and output performance. The obtained numerical results are in good agreement with the experimental and theoretical values, which verifies the effectiveness of the simulation model. The maximum plunge amplitude is 0.029 m and the output voltage is 15.51 V at 17.74 m/s and an installation angle of 0o. The enhancement ratio of the output voltage at 0o is up to 148.6% over 45o, which achieves better harvesting performance. The designed harvester system powers indirectly the pedometer for 104 s at 13.58 m/s. This research offers an essential foundation for achieving better tradeoffs in energy harvesting and vibration suppressing by appropriately selecting the flap installation angle. [Display omitted] • This paper first proposes a novel energy harvester with various installation angle flaps. • Flap alters the flow field, restricts vortex shedding, and increases output characteristics. • The maximum harvested plunge amplitude is 0.029 m and the output voltage is 15.51 V. • The enhancement ratio of the output voltage at 0o is up to 148.6% over 45o. • The harvester drives indirectly the pedometer for 104 s at 13.58 m/s. [ABSTRACT FROM AUTHOR]

Sugarcane is one of the main commodities in the world economy. An important step in the sugarcane supply chain is the harvest stage, requiring the support of mathematical modeling and optimization tools. Integrating the process of choosing the areas for harvesting according to the sugarcane maturation with the formation of the harvesting fronts and associating them with machine relocation costs is challenging. This paper contributes with a novel integer mathematical model that considers these concerns using three conflicting objectives. The first is that the sugarcane should be harvested as close as possible to its maturity, considering the sugarcane should be harvested as close as possible to its maturity by considering a combined measure of temperature and time since planting. The second aims to minimize the number of harvest fronts. The third objective is to minimize the costs involved with the relocation of the harvesters that cut the cane. Different strategies for obtaining Pareto-optimal solutions were proposed using exact methods, including MIP start and a decomposition technique. In the worst case, solutions with tolerable integrality gaps were obtained (inferior to 3%) in less than 1.5 h. Computational tests in real case studies were conducted in the sugarcane industry in two countries, indicating strong trade-offs in the determined solutions. In the Brazilian case, harvesting as close to maturation as possible, for example, causes an increase of 158% in the number of harvest fronts and 47% in the transportation costs, considering the minimum values for these objectives. Other trade-offs were seen and discussed when one of the other objectives was prioritized. These different compromise solutions help the decision-makers choose the most appropriate harvesting schedule according to their preferences. • We propose a new MIP optimization model to determine the harvesting of sugarcane. • The model aims to optimize three conflicting objectives. • A new method of computing cane maturation is used: the concept of degree-days. • A procedure for determining Pareto solutions by exact methods is proposed. [ABSTRACT FROM AUTHOR]