Investigando o efeito de campos elétrico e magnético em um sistema dissipativo pulsante

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

A fÍsica de partÍculas elementares e o Prêmio Nobel de física 2008

The 2008 Nobel prize of physics pay tribute to three theoretical physicist by their work related to some symmetries of Nature. We briefly comments the importance of these works and the context in which they were done.

Estudo de sistemas não lineares em teoria de campos em baixas dimensões

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Sólitons e caos em teorias de campos: um estudo

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Formalismo de Hamilton-Jacobi generalizado: teorias de campos com derivadas de ordem superior

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Modelo tectono-estrutural dos campos de petróleo Namorado, Cherne e Albacora

The main goal in this research is a tectono-estructural characterization of the Cherne, Albacora and Namorado Fields, located at Campos Basin, in order to investigate the relationship between the geologic evolution and the rock´s physical properties of the reservoir, and how they affect the hydrocarbon accumulation in those fields. Well correlations show that the inferior turbidites have a regional lateral continuity. Basic petrophysics analysis, calculated here, shows that the three fields present porosity values that range from 15 to 20%, shale volume range from 26 to 30% and formation water saturation range from 23 to 45%, based on formation water resistivity dada from Albacora Field. Petrophysics maps feature a trend in Albacora Field that increase the porosity values to SE, and in Cherne and Namorado Field the trend increase towards N. Seismic horizons where interpreted between the first appearance of the Namorado Sandstone and the top of Quissamã Formation. This interval presents normal listric faulting, in Cherne and Namorado Field with NWSE and NE-SW direction, and sedimentation trend to NW-SE, in Albacora Field the faulting presents a NNE-SSW and N-S direction, with a sedimentation trend to NE-SW. Seismic attribute maps present amplitude anomalies close to the producing wells, and on Namorado Field, it indicates a potential hydrocarbon accumulation in the NE region. For each field is indicated laboratory tests for a better characterization of the petrophysical properties, since that they don’t form the same reservoir level, therefore, not influencing the water saturation calculation

Estudo, construção e caracterização de diodos orgânicos tipo Schttky

During the twentieth century the inorganic electronics was largely developed being present in various industrial equipment or household use. However, at the end of that century were verified electronic properties in organic compounds, giving rise to the field of organic electronics. Since then, the physical properties of elementary devices such as diodes and organic transistors have been studied. In this work was studied the properties of diode devices fabricated with a semiconductor polymer, the poly-o-methoxyaniline (POMA). Devices containing electrodes of Au and Al were fabricated with semiconductor polymer of different doping levels. We found that the rectifying behavior for the heterojunctions metal/polimer are reached only for high doping level (with conductivity greater than 1,77. 10-9 S / cm), which gives the devices characteristic of a Schottky diode. The rectifying behavior was observed for electric fields of low magnitude, below the operating field (~ 600 V/cm), while for electric field greater than 600 V/cm the a linear behavior I vs.V was obtained. We determined that this Ohmic behavior arises from the charge transport over the volume of the semiconductor material after the lowering of the metal/semiconductor barrier. In devices with weakly doped semiconductor, the electrical resistance of the volume becomes high and the process of charge transportation is dominated by the volume, for any intensity of the applied electric field

Efeitos de campos elétrico e magnético em um sistema dissipativo pulsante

The main idea of this work is to understand and analyze the dynamical aspects of the motion of a particle moving in the annular billiard, which corresponds to two circles of radius R and r (rdescribe the system by introducing breathing boundaries that transfer momentum to the particle. Likewise, the collisions with the circles are studied in the conservative (elastic) and dissipative (non-elastic) cases. When we introduce magnetic and electric fields, the particle is submitted to the Lorentz force. It also can suffer successive collisions with the breathing circles, winning or losing energy. For the elastic time-dependent case, we have already observed that a particle can gain unlimited energy. The purpose of this work is to study the effects of both external fields in the mean energy of the system, for the time-dependent case with and without dissipation. Our initial results conduct us to believe that electrical field can contribute to the increasing of mean energy, and a magnetic field applied to the vertical axis of coordinate (what guarantees the particle do not travel away the billiard’s plane) uses to arrest the particle to the whispering gallery orbits and do not contribute to the Fermi acceleration indeed. However, in presence of the electric field, to same values, the magnetic one together can improve this referred process, obtaining greater energy values to the same number of iterations. These results are applied to the concentric case, that was reported did not haven any significant energy gain on the free particle motion

Crises de fronteira e estruturas complexas no espaço de parâmetros em um mapeamento dissipativo bidimensional

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Aspectos quânticos e clássicos da instabilidade de campos fundamentais em espaços-tempos astrofísicos

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

Extração automática de contornos de telhados usando dados de varredura a laser e campos randômicos de Markov

This paper proposes a methodology for automatic extraction of building roof contours from a Digital Elevation Model (DEM), which is generated through the regularization of an available laser point cloud. The methodology is based on two steps. First, in order to detect high objects (buildings, trees etc.), the DEM is segmented through a recursive splitting technique and a Bayesian merging technique. The recursive splitting technique uses the quadtree structure for subdividing the DEM into homogeneous regions. In order to minimize the fragmentation, which is commonly observed in the results of the recursive splitting segmentation, a region merging technique based on the Bayesian framework is applied to the previously segmented data. The high object polygons are extracted by using vectorization and polygonization techniques. Second, the building roof contours are identified among all high objects extracted previously. Taking into account some roof properties and some feature measurements (e. g., area, rectangularity, and angles between principal axes of the roofs), an energy function was developed based on the Markov Random Field (MRF) model. The solution of this function is a polygon set corresponding to building roof contours and is found by using a minimization technique, like the Simulated Annealing (SA) algorithm. Experiments carried out with laser scanning DEM's showed that the methodology works properly, as it delivered roof contours with approximately 90% shape accuracy and no false positive was verified.

Kant e o problema da origem das representações elementares: apontamentos

Il s'agit d'examiner l'origine des représentations fondamentales (formes de la réceptivité et formes intelectuelles )face à la critique faite par Kant des idées innées et abstraites.

Short-term changes caused by fire and mowing in Brazilian Campos grasslands with different long-term fire histories

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Os problemas de espalhamento quântico em potenciais elementares

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