This work aims to investigate the efficiency of a novel organic mineral fertilizer produced with filter cake residue from sugarcane mills. The novel fertilizer was developed based on the mixing of minerals with an organic compost, conditioning, and pelletizing of mixture. The minerals consist of conventional soluble mineral nutrients and the organic phase consists of insoluble filter cake compost obtained from an assisted composting process. Efficiency of conventional and organic mineral fertilizers was measured in real field soybean crop through a randomized block design with four replications. Variables analyzed were productivity, NPK nutrient in leaves. The experiment was carried out in Tupaciguara/MG, Brazil. Experimental results showed higher soybean productivity and leaf nitrogen content in the organic mineral treatments than mineral ones in all dosages tested, with statistical relevance for 80% and 100% NPK dosages.
This work deals with implementation of an experimental flowrate control unit using free and low-cost hardware and software. The open-source software Processing was used to develop the source codes and user graphical interface and the open-source electronic prototyping platform Arduino was used to acquire data from an experimental unit. Work presents descriptions of the experimental setup, the real-time PID controllers used and theoretical/conceptual issues of Arduino. PID controllers based on internal model control, minimization of the integral of time-weighted absolute error, Ziegler-Nichols, and others were tuned for setpoint and load changes and real-time runs were carried out in order to make real-time use of control theory learned in academy. Results showed the developed platform proved to be suitable for use in experimental setups allowing users compare their ideas and expectations with the experimental evidence in a real and low-cost fashion. In addition, the instrumentation is simple to configure with acceptable level noise and particularly useful for control/automation learning with educational purposes.
Complex space missions involving large angle maneuvers and rapid attitude control, require new non-linear control techniques to design the Satellite Control System (SCS) in order to have reliability and adequate performance. In that context, one investigates a new SCS technique based on the State Dependent Riccati Equation (SDRE) methodology which can be considered as an adaptive form of the Linear Quadratic Regulator (LQR) but which allows to deal with the non linearities of the system. A nonlinear mathematical model of a flexible rotatory beam is built through the Lagrangian formulation where the flexible displacement is modelled using the assumed modes theory and a structural damping is added applying the Rayleigh technique. The SDRE controller objectives are to control the hub angular position and simultaneously to damp the flexible displacements. A computational procedure is developed which allows drawing a performance map of the system showing all SDRE reachable performances. Using this control algorithm one can obtain the Pareto's border representing the set of optimal performances. On the other hand, analyzing the influence of the weight matrixes terms, it is shown that it is possible to get the Pareto's border performances using only a few terms of the SDRE weight matrixes. On the basis of this analysis, a control law enabling to get weight matrixes' values as a function of a required performance is developed. Last of all, state dependent weight matrixes are used to show that they can improve the system performance. Based on the results, it turned out that the SDRE's performance is better than the LQR's one, not only because it can deal with non linearities, but also because its design is more flexible and permits to control the rigid-flexible satellite in the same time interval and spending less energy.
RESUMO-O objetivo deste trabalho foi comprovar cientificamente o efeito de liberação gradual de nutrientes de um fertilizante organomineral em relação ao fertilizante mineral convencional. A metodologia se baseou na medição da solubilização de fósforo e potássio em solução aquosa em função do tempo. O fertilizante organomineral utilizado foi preparado por oclusão com processo de peletização com aditivos. combinado efeito de temperatura, pressão e umidade. Os resultados mostram um efetivo efeito retardador do fertilizante organomineral em relação ao fertilizante mineral.
RESUMO-O objetivo deste trabalho foi investigar o efeito do uso de fertilizante organomineral produzido a partir de resíduo de torta de filtro de usinas sucroenergéticas sobre a produtividade de campo de cana planta e comparar com a produtividade do fertilizante mineral normalmente empregado pelas usinas. Foram utilizadas doses variáveis de ambos fertilizantes na produtividade de cana planta em área de campo. O experimento foi instalado em Uberlândia/MG na Bioenergética Aroeira. O delineamento experimental foi de blocos ao caso com sete tratamentos e cinco repetições. Foram avaliados o teor de NPK foliar e a produtividade da cana. A produtividade do organomineral foi superior à do mineral em 12,4% em média em todas as doses testadas.
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