RSS 1.0Artigos - Física e Química - FEG
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Morphological and structural variations in anodic films grown on polished and electropolished titanium substrates
Da Silva Palma, Dener Pedro
; Nakazato, Roberto Zenhei ; Codaro, Eduardo Norberto ; Acciari, Heloisa Andréa (Materials Research, 2019) [Artigo]
The objective of this work was to investigate the effects of anodization parameters on the anatase phase formation of titanium oxide films, which have been grown on both electropolished and nonelectropolished titanium ... -
Quantum dynamics of scalar particles in the space–time of a cosmic string in the context of gravity's rainbow
; ; ; Castro, L. B.; (Annals of Physics, 2020) [Artigo]
We analyze the dynamics of scalar particles in gravity's rainbow considering the space–time of a cosmic string in this modified gravity. Thus, we solve the Klein–Gordon equation for two types of potential in which two ... -
Theoretical modeling and experimental validation of hydrodynamic cavitation reactor with a Venturi tube for sugarcane bagasse pretreatment
Bimestre, Thiago Averaldo; ; ; Canettieri, ElianaVieira ; Tuna, Celso Eduardo (Bioresource Technology, 2020) [Artigo]
A hydrodynamic cavitation reactor with a Venturi tube was modeled through a computational fluid dynamics approach in order to evaluate the influence of pressure ratio, diameter and length of the throat zone. A cavitation ... -
Gaussian process estimation of transition redshift
Jesus, J. F.; ; Escobal, A. A. ; Pereira, S. H. (Journal of Cosmology and Astroparticle Physics, 2020) [Artigo]
This paper aims to put constraints on the transition redshift zt, which determines the onset of cosmic acceleration, in cosmological-model independent frameworks. In order to do that, we use the non-parametric Gaussian ... -
Comment on “Dirac fermions in Som–Raychaudhuri space-time with scalar and vector potential and the energy momentum distributions [Eur. Phys. J. C (2019) 79:541]”
; ; Castro, Luis B. (European Physical Journal C, 2020) [Nota]
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Unitarity of Singh-Hagen Model in D Dimensions
Mendonca, Elias L.; Schimidt Bittencourt, R. (Advances in High Energy Physics, 2020) [Artigo]
The particle content of the Singh-Hagen model (SH) in D dimensions is revisited. We suggest a complete set of spin-projection operators acting on totally symmetric rank-3 fields. We give a general expression for the ... -
New point-like sources and a conducting surface in Maxwell–Chern–Simons electrodynamics
Borges, L. H.C.; ; ; Oliveira, H. L. ; ; (European Physical Journal C, 2020) [Artigo]
We investigate some aspects of the Maxwell–Chern–Simons electrodynamics focusing on physical effects produced by the presence of stationary sources and a perfectly conducting plate (mirror). Specifically, in addition to ... -
On the generalized spinor classification: beyond the Lounesto’s classification
; ; ; Beghetto, D. (European Physical Journal C, 2020) [Artigo]
In this paper we advance into a generalized spinor classification, based on the so-called Lounesto’s classification. The program developed here is based on an existing freedom on the spinorial dual structures definition, ... -
Mirrors and field sources in a Lorentz-violating scalar field theory
Borges, L. H.C.; ; (Nuclear Physics B, 2020) [Artigo]
In this paper we consider classical effects in a model for a scalar field incorporating Lorentz symmetry breaking due to the presence of a single background vector vμ coupled to its derivative. We investigate of the ... -
Comment on “Comment on Linear confinement of a scalar particle in a Gödel-type space-time”
; ; Castro, Luis B. (European Physical Journal C, 2020) [Nota]
We show that from an appropriate manipulation of the biconfluent Heun differential equation one can obtain the correct expression for the energy eigenvalues for the Klein–Gordon equation without potential in the background ... -
Unitarity of higher derivative spin-3 models
Mendonça, E. L.; Schimidt Bittencourt, R. (Annals of Physics, 2020) [Artigo]
The fourth order in derivatives New Massive Gravity model NMG, describes a massive spin-2 particle in D=2+1. At the linearized level a proof of unitarity necessarily implies that the generalization to higher dimensions ... -
Scalar bosons with Coulomb potentials in a cosmic string background: scattering and bound states
; ; ; Castro, Luis B. (European Physical Journal Plus, 2020) [Artigo]
The relativistic quantum motion of scalar bosons under the influence of a full vector (minimal Aμ and nonminimal Xμ) and scalar (Vs) interactions embedded in the background of a cosmic string is explored in the context of ... -
Acceleration in Friedmann cosmology with torsion
Pereira, S. H.; Lima, R. de C. ; Jesus, J. F. ; (European Physical Journal C, 2019) [Artigo]
A Friedmann like cosmological model in Einstein–Cartan framework is studied when the torsion function is assumed to be proportional to a single ϕ(t) function coming just from the spin vector contribution of ordinary matter. ... -
Soldering spin-3 opposite helicities in D=2+1
Dalmazi, D.; ; Mendonça, E. L. ; Bittencourt, R. Schimidt (Physical Review D, 2019) [Artigo]
Here we present the soldering of opposite helicity states of a spin-3 particle, in D=2+1, into one parity doublet. The starting points may be either the sixth- or fifth-order (in derivatives) spin-3 self-dual models of ... -
More on dual actions for massive spin-2 particles
Dalmazi, D.; (Classical And Quantum Gravity, 2020) [Artigo]
Here we start from a dual version of Vasiliev's first order action for massless spin-2 particles (linearized first order Einstein-Hilbert) and derive, via Kaluza-Klein dimensional reduction fromD+ 1 toDdimensions, a set ... -
Gravitational entropy of wormholes with exotic matter and in galactic halos
Lima, R. de C.; ; Pereira, S. H. (International Journal Of Modern Physics D, 2020) [Artigo]
In this work, we study and compare the features of gravitational entropy near the throat of transversable wormholes formed by exotic matter and wormholes in galactic halos. We have verified that gravitational entropy and ... -
Study of diglyme plasmas by mass spectrometry
; Honda, Roberto Y.; Algatti, Mauricio A. ; Mota, Rogerio P. ; Kayama, Milton E. ; (2017 16th Latin American Workshop On Plasma Physics (lawpp 2017), 2017) [Trabalho apresentado em evento]
This paper deals with the study of the fragmentation process of diethylene glycol dimethyl ether (diglyme) molecule, i.e., (CH3OCH2CH2)(2)O; in low pressure RF excited plasma discharges. The study was carried out using ... -
Characterization of SiC and Al2O3 Ceramics Exposed to Nitrogen Ions from Inverse-Z Pinch Plasma Discharge
Algatti, Mauricio A.; Santos, Carlos N. ; Mota, Rogerio P. ; Campos, Elson de ; ; ; ; (2017 16th Latin American Workshop On Plasma Physics (lawpp 2017), 2017) [Trabalho apresentado em evento]
Silicon carbide ceramics are used for several industry applications, such as structural coating, ballistic armor, thermal coating protection, high performance mirror substrate, catalyst supports, etc. In this work, dense ... -
THE NEAR-EARTH ASTEROID CHARACTERIZATION AND OBSERVATION (NEACO) MISSION
; ; ; ; Motta, Gabriel Borderes; ; Santos, Josue Cardoso dos ; ; ; et al. (Astrodynamics 2017, Pts I-iv, 2018) [Trabalho apresentado em evento]
The Near-Earth Asteroid Characterization and Observation (NEACO) mission proposes to explore the fast-rotating asteroid (469219) 2016 HO3 with a SmallSat spacecraft and perform an early scientific investigation to enable ... -
Casimir effect for gauge scalars: The Kalb-Ramond case (vol 72, art no 105012, 2005)
(Physical Review D, 2006) [Errata]