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Three distinct sol-gel synthesis methodologies were employed to fabricate niobium catalysts supported on stainless steel meshes via the dip-coating technique, with the objective of their utilization in layered configurations for water purification applications. The structured catalysts were subjected to calcination at three varying temperatures: no calcination, calcination at 823 K, and calcination at 1173 K. Ibuprofen, selected as the model pollutant due to its emerging contaminant profile, was utilized for evaluation. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) images, in conjunction with adhesion assessments, elucidated that thermally treated catalysts exhibited nearly 80% retention of Nb2O5 nanoparticles adhered uniformly to the support surface. In batch reactor experiments, the catalyst derived from the NbCl5 precursor and polyacrylonitrile (PAN) exhibited the most promising performance, achieving a 90% degradation of the contaminant within a 120 min timeframe. This catalyst, exhibiting superior efficacy, was subsequently employed in tests utilizing photocatalytic bench reactors, where it demonstrated analogous performance to that observed in the batch reactor setup. Upon upscaling to a high-capacity photocatalytic prototype, the degradation efficiency was sustained above that observed in photolytic testing, even after four utilization cycles. [ABSTRACT FROM AUTHOR]

Abstract Modern high-performance aircrafts operate in regular flight regimes, in which the nonlinearities of the system directly influence the dynamical response of the aircraft. This work studies the dynamics of a fighter aircraft operating at high angles of attack of the wing. A mathematical model was developed deriving a system of nonlinear dynamical differential equations representing the longitudinal flight of the aircraft, considering the effect of the variation of the wind speed due to the atmospheric turbulence in the dynamic response of the aircraft. The dynamics of the aircraft is modeled as a two-degrees-of-freedom system, and the variation of the wind gusts is considered as a single-degree-of-freedom system. The analysis of the behavior of the system is carried out through the 0–1 test method to determine if the system is chaotic or periodic, which is applied in relation to the speed and angle of attack of the aircraft. As an object of study, all the considerations and analyses regarding the F-8 aircraft "Crusader" were took into account. A control technique is proposed in a nonlinear way, at which the angle of tail deflection is considered as a control parameter and projected using the method of control of the State Dependent Riccati Equations (SDRE) in order to stabilize the wing angle oscillations, considering critical regions of the behavior of the aircraft. Numerical simulations demonstrated the efficiency of the SDRE control, taking into account the comparison of the dynamics of the system with and without control, by using phase planes and parametric uncertainties, where the controller showed to be able to respond quickly and reliably to recover the aircraft from a stall situation. [ABSTRACT FROM AUTHOR]

This work aims to analyze two metaheuristics optimization techniques, Genetic Algorithm (GA) and Particle Swarm Optimization (PSO), with six variations each, and compare them regarding their convergence, quality, and dispersion of solutions. The optimization target is the Gaussian Adaptive PID control (GAPID) to find the best parameters to achieve enhanced performance and robustness to load variations related to the traditional PID. The adaptive rule of GAPID is based on a Gaussian function that has as adjustment parameters its concavity and the lower and upper bound of the gains. It is a smooth function with smooth derivatives. As a result, it helps avoid problems related to abrupt increases transition, commonly found in other adaptive methods. Because there is no mathematical methodology to set these parameters, this work used bio-inspired optimization algorithms. The test plant is a DC motor with a beam with a variable load. Results obtained by load and gain sweep tests prove the GAPID presents fast responses with very low overshoot and good robustness to load changes, with minimal variations, which is impossible to achieve when using the linear PID. [ABSTRACT FROM AUTHOR]

Renewable energy sources for vehicles have been the motivation of many researches around the world. The reduction of fossil fuels deposits and increase of the pollution in cities bring the need of more efficient and cleaner energy sources. In this way, this work will present the application of a compressed air engine applied to a bicycle. The engine is composed of two pneumatic cylinders connected to the bicycle wheel through a crank-connecting-rod mechanism. In order to control the velocity of the bicycle, a strategy of control composed of two controls was implemented: a feedback and a feedforward control. For feedback control, the State-Dependent Riccati Equation (SDRE) control and also a proportional-derivative (PD) control are considered, considering three cases for velocity bicycle variation: 10 km/h, 20 km/h, and 30 km/h. The equations of motion of the system were obtained through the Lagrangian energy method. Numerical simulations were performed in order to analyze the dynamics of the system and the efficiency of the controllers. [ABSTRACT FROM AUTHOR]