97 resultados para Electric charge and distribution


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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Despite remarkable significance of Pantanal for the conservation of aquatic birds, the status of their populations, the spatiotemporal patterns of distribution and habitat use and structure of communities are little known. Thus, we studied three aquatic environments (Negro river, bays and salines) from 2007 to 2009 in the Nhecolandia Pantanal to verify the distribution and composition of aquatic birds and also if there is significant seasonal influence on these aspects. We adopted the transect method (288 hours of sampling) and recorded 135 species (7.834 individuals). The Negro river showed the highest diversity, while the salines the lowest. The similarity of aquatic bird communities was higher between bays and salines, followed by Negro river and bays and lower between salines and Negro river. The equidistribution is more variable in the salines and more stable in the Negro river. The environments strongly differ from each other in aquatic bird composition in space (habitat use and distribution) and time (seasonal water fluctuations). The diversity of bird community in the dry season varies significantly in the salines, followed by the bays and more stable in the Negro river. The Negro river, regardless of large annual amplitude of flow, is more seasonally stable since its riparian vegetation is continuous (not isolated) and constant. These aspects provide better conditions to stay all year, contributing to decrease the seasonal nomadic tendencies of aquatic birds. Finally, all these data provide strong arguments to the preservation of all phytophysiognomies in the Nhecolandia sub-region of Pantanal, but with special attention to the salines widely used by many flocks of aquatic birds (mainly in the dry season) and migrant and/or rare species restricted to this habitat.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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In this paper the dynamical interactions of a double pendulum arm and an electromechanical shaker is investigated. The double pendulum is a three degree of freedom system coupled to an RLC circuit based nonlinear shaker through a magnetic field, and the capacitor voltage is a nonlinear function of the instantaneous electric charge. Numerical simulations show the existence of chaotic behavior for some regions in the parameter space and this behaviour is characterized by power spectral density and Lyapunov exponents. The bifurcation diagram is constructed to explore the qualitative behaviour of the system. This kind of electromechanical system is frequently found in robotic systems, and in order to suppress the chaotic motion, the State-Dependent Riccati Equation (SDRE) control and the Nonlinear Saturation control (NSC) techniques are analyzed. The robustness of these two controllers is tested by a sensitivity analysis to parametric uncertainties.

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Herbicides application success depends, besides product correct choice, the observation of environmental conditions and application quality. The work aimed to quantify the effects of surfactant addition in spraying solution, in natural and artificial targets, associated to different nozzle boom angles in relation to application offset, by using distinct evaluation methods. Two experiments were conducted at NuPAM-FCA/UNESP, Botucatu County, São Paulo State, constituted by ten treatments, in factorial scheme 2 × 5, corresponding to two spraying solutions conditions (absence or presence of Aterbane BRTM (0.25% v/v) adjuvant) and five angles of spray nozzle in relation to offset application (-30°, -15°, 90°, +15° and +30°). In Ipomea grandifolia leaves, the distribution and drops deposition of a tracer solution were evaluated by using scores visual and spectrophotometer process. In hydro sensible papers, volumetric medium diameter (VMD), density (cm2 ) and drops medium diameter, covered area (%) and application fees (L ha-1) were evaluated through e-SprinkleTM software. Aterbane BRTM (0.25% v/v) presence or absence, associated or no, to spray nozzles offset did not provide significant differences in I. grandifolia spray deposition. The use of artificial targets presented applicative technical limitations in relation to the use of natural ones as study matrix. Deposit and distribution variables esteem distinct behaviours, independent of target nature.