805 resultados para Raspberry pi
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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In this article, it is represented by state variables phase a transmission line which parameters are considered frequency independently and frequency dependent. Based on previous analyses, it is used the reasonable number of p circuits and the number of blocks composed by parallel resistor and inductor for reduction of numerical oscillations. It is analyzed the influence of the increase of the RL parallel blocks in the obtained results. The RL parallel blocks are used for inclusion of the frequency influence in the transmission line longitudinal parameter. It is a simple model that is been used by undergraduate students for simulation of traveling wave phenomena in transmission lines. Considering the model without frequency influence, it is included a representation of the corona effect. Some simulations are carried considering the corona effect and they are compared to the results without this phenomenon.
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In this article, it is represented by state variables phase a transmission line which parameters are considered frequency independently and frequency dependent. It is analyzed what is the reasonable number of pi circuits and the number of blocks composed by parallel resistor and inductor in parallel for reduction of numerical oscillations. It is simulated the numerical routine with and without the effect of frequency in the longitudinal parameters. Initially, it is used state variables and pi circuits representing the transmission line composing a linear system which is solved by numerical routines based on the trapezoidal rule. The effect of frequency on the line is synthesized by resistors and inductors in parallel and this representation is analyzed in details. It is described transmission lines and the frequency influence in these lines through the state variables.
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In this paper we use the Hermite-Biehler theorem to establish results for the design of proportional plus integral (PI) controllers for a class of time delay systems. We extend results of the polynomial case to quasipolynomials using the property of interlacing in high frequencies of the class of time delay systems considered. A signature for the quasipolynomials in this class is derived and used in the proposed approach which yields the complete set of the stabilizing PI controllers.
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Soil degradation can be defined as a process that reduces the ability of soil to produce property or services. Thus, the objective was to study the influence of topography and erodibility in the distribution of the chemical attributes of an Alfissol in degraded areas of Gilbués in the State of Piaui, Brazil. In the chosen area a sampling grid of 1 ha was demarcated, with points spaced at 10 x 10 m, and 121 samples were collected at intersections, in 0-0.20 m depth. Each point was georeferenced as a way to demarcate the area and prepare a topography map. For all samples pH, organic matter, phosphorus, potassium, calcium, magnesium, hydrogen and aluminum were determined. The estimate of erodibility was calculated from the equation proposed by Denardin. Based on the experiment and the results obtained it is concluded that the number of samples used was sufficient to determine the variability of soil in degraded areas of the Gilbués municipality. The discontinuity in the topography of the landscape and erodibility cause a moderate degree of heterogeneity in most chemical properties of the studied soil, establishing specific management zones.
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The aim of this work was to determine crop coefficients (Kc) of drip irrigated watermelon in the climatic and growing conditions of the Gurgueia Vale, State of Piaui, Brazil, located at 8 ° 26' S, 43 ° 47' W and altitude of 251 m. The reference evapotranspiration (ET0) was determined by the sum of hourly values of ET0 obtained by the Penman-Monteith method parameterized by FAO with climatic data obtained from an automatic weather station. The daily crop evapotranspiration (ETc) was measured by three weighing lysimeters of load cells. Aiming high fruit yield in this region, we recommend that the following local values of Kc and Kcb be used for planning and management of irrigation, respectively: initial stage (crop establishment) - 0.34 and 0.24; intermediate stage (growth and fruit maturation) - 1.16 and 1.10; end stage (harvest) - 0.93 and 0.86. These Kc values of initial and intermediate phases are statistically higher than the values of Kc and Kcb already adjusted according to the methodology presented in the FAO Irrigation and Drainage Paper 56. The values of Kc and Kcb at the end phase are not statistically different from the FAO values.
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Pós-graduação em Física - IFT
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Pós-graduação em Física - IFT
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Pós-graduação em Geografia - IGCE
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Pós-graduação em Geografia - IGCE
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Pós-graduação em Geografia - IGCE
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Pós-graduação em Geografia - IGCE
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Pós-graduação em Geografia - IGCE
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)