Sistema de aterramento com cabo contrapeso representado por linhas de transmissão implementado em Matlab com circuitos em cascatas de PÍ

Pós-graduação em Engenharia Elétrica - FEIS

O risco ambiental representado por campos eletromagnéticos em Presidente Prudente (SP)

Currently the mobile services represent an essential tool in daily life of the population. However, while offering greater convenience to its users, there is growing concern about the harmful effects to human health, derived from daily exposure of the public to electromagnetic fields from radio base stations (RBS), since even today, there is no study proving that longterm exposure to low-level fields are not harmful to health. In Presidente Prudente has not been a study reporting values of measurements of electromagnetic fields from base stations installed in the city. Based on these data, this study aimed to assess the levels of electromagnetic exposure in the city of Presidente Prudente regarding recommended by international bodies, as well as propose measures that can reduce public exposure to electromagnetic fields. For measuring values of electromagnetic fields, we used appliance Electromagnetic Field Meter Portable Digital - DRE-050, the Instrutherm, following the methodology suggested and adapted from the Adilza Condessa Dode’study. In total, 49 points were mapped corresponding to the areas at risk of exposure to electromagnetic fields generated by the substations of power grid, transmission towers and telecommunication towers located in the city of Presidente Prudente (SP)

Emprego do método eletromagnético (em) na investigação e mapeamento de contaminações geradas por cemitérios: o caso de Monte Alto/SP

The use of geophysical methods in the analysis and mapping of likely contamination plumes has shown a huge value in the development of researches related to environmental issues. Among the main geophysical methods applied to this purpose, the geoelectrical methods stand out, being based on the use of electric and electromagnetic fields. The electromagnetic method (EM) uses physical environment responses created by electromagnetic field propagation, consisting of an alternated electric output and a magnetization force, used to obtain the electric conductivity (σ) of the subsurface materials. It has a broad application in the mineral exploration and prospection, and its use has been also efficient in environmental researches. By the electromagnetic method, this work examined and mapped possible contaminations created by cemetery leachate in the Saudade's Cemetery, located in the city of Monte Alto, Sao Paulo, where sedimentary rocks of the Bauru Group are exposed. Cemetery leachate is a putrefactive liquid, generated from the decomposition of organic matter, which contains substances that can contaminate soil and groundwater. Results achieved in this work show that the use of the electromagnetic method is an important indirect tool in the investigation of environmental contaminations in areas with highly contrasting physical properties

Sobre a desintegração de prótons em movimento circular em campos gravitacionais

Pós-graduação em Física - IFT

Exotic dark spinor fields

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Model to localize gauge and tensor fields on thick branes

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Absorption cross section of electromagnetic waves for Schwarzschild black holes

The absorption cross section of black holes has been investigated for various fields. Nevertheless, the absorption cross section of Schwarzschild black holes for the electromagnetic field has been only calculated in the low- and high-frequency approximations until now. Here we compute it numerically for arbitrary frequencies.

Duffin-Kemmer-Petiau and Klein-Cordon-Fock equations for electromagnetic, Yang-Mills and external gravitational field interactions: proof of equivalence

Starting from the Generating functional for the Green Function (GF), constructed from the Lagrangian action in the Duffin-Kemmer-Petiau (DKP) theory (L-approach) we strictly prove that the physical matrix elements of the S-matrix in DKP and Klein-Gordon-Fock (KGF) theories coincide in cases of interacting spin O particles with external and quantized Maxwell and Yang-Mills fields and in case of external gravitational field (without or with torsion), For the proof we use the reduction formulas of Lehmann, Symanzik and Zimmermann (LSZ). We prove that many photons and Yang-Mills particles GF coincide in both theories too. (C) 2000 Elsevier B.V. B.V. All rights reserved.

Functional Analysis for Gauge Fields on the Front-Form and the Light-Cone Gauge

Constrained systems in quantum field theories call for a careful study of diverse classes of constraints and consistency checks over their temporal evolution. Here we study the functional structure of the free electromagnetic and pure Yang-Mills fields on the front-form coordinates with the null-plane gauge condition. It is seen that in this framework, we can deal with strictu sensu physical fields.

Neutrinos and electromagnetic gauge invariance

We examine a recently proposed connection constraining U(1)(em) electromagnetic gauge invariance and the nature of neutrino mass terms in the framework of G(0) = SU(3)(C) x G(W) x U(1)(N) gauge extensions of the standard model where G(W) denotes the weak isospin special unitary extended groups. We show that in a large class of G(0) models there is a unique fermion representation content and scalar fields which select the neutrino mass terms. Noteworthy. even though there are mathematically equivalent representation contents then can be different aspects concerning the physical consequences which are not a mere truism.

Manifest electromagnetic duality in closed superstring field theory

The free action for massless Ramond-Ramond fields is derived from closed superstring field theory using the techniques of Siegel and Zwiebach. For the uncompactified Type IIB superstring, this gives a manifestly Lorentz-covariant action for a self-dual five-form field strength. Upon compactification to four dimensions, the action depends on a U(1) field strength from 4D N = 2 supergravity. However, unlike the standard Maxwell action, this action is manifestly invariant under the electromagnetic duality transformation which rotates F-mn into epsilon(mnpq)F(pq).

The propagator for a charged oscillator with a time-dependent mass in a time-varying electromagnetic field

We make a change of variables and a time reparametrization in the Schrödinger equation in order to obtain the propagator of a charged oscillator with a time-dependent mass and frequency under the influence of time-varying electric and magnetic fields, in terms of the simple propagators of harmonic oscillators with constant frequencies and masses. We also discuss the Jackiw transformation and others as a particular case of ours. © 1991.

Duality in a fermionlike formulation for the electromagnetic field

We employ the Dirac-like equation for the gauge field proposed by Majorana to obtain an action that is symmetric under duality transformation. We also use the equivalence between duality and chiral symmetry in this fermionlike formulation to show how the Maxwell action can be seen as a mass term. ©2000 The American Physical Society.

Gravitomagnetic moments of the fundamental fields

The quadratic form of the Dirac equation in a Riemann space-time yields a gravitational gyromagnetic ratio κ(S) = 2 for the interaction of a Dirac spinor with curvature. A gravitational gyromagnetic ratio κ(S) = 1 is also found for the interaction of a vector field with curvature. It is shown that the Dirac equation in a curved background can be obtained as the square-root of the corresponding vector field equation only if the gravitational gyromagnetic ratios are properly taken into account.

Podolsky's electromagnetic theory on the null-plane

We have analyzed the null-plane canonical structure of Podolsky's electromagnetic theory. As a theory that contains higher order derivatives in the Lagrangian function, it was necessary to redefine the canonical momenta related to the field variables. We were able to find a set of first and second-class constraints, and also to derive the field equations of the system. Copyright © owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence.