On Lorentz violation in e− ⁣ ⁣+ ⁣e+ ⁣→ ⁣μ− ⁣ ⁣+ ⁣μ+e^{-}\!\!+\!e^{+}\!\rightarrow\!\mu^{-}\!\!+\!\mu^{+} scattering at finite temperature

Small violation of Lorentz and CPT symmetries may emerge in models unifying gravity with other forces of nature. An extension of the standard model with all possible terms that violate Lorentz and CPT symmetries are included. Here a CPT-even non-minimal coupling term is added to the covariant derivative. This leads to a new interaction term that breaks the Lorentz symmetry. Our main objective is to calculate the cross section for the $e^{-}\!\!+\!e^{+}\!\rightarrow\!\mu^{-}\!\!+\!\mu^{+}$ scattering in order to investigate any violation of Lorentz and/or CPT symmetry at finite temperature. Thermo Field Dynamics formalism is used to consider finite temperature effects.Comment: 12 pages, 1 figure, accepted for publication in PL

Mathematical Methods applied in Image Enhancement using Matlab

In order to characterize complex engineering problems involvinging image data acquisition, different techniques in image processing can be used. One of those techniques is called the Laplacian Filter, commonly used to reduce noise and improving images. Based on that, image segmentation is a widely applied tool in engineering and it can greatly contribute in the acceleration of processes instead of adopting conventional methods, thus providing applications of such technique in the medical, spatial and other sectors linked to engineering. Therefore, this work aims to use image segmentation through differential equations (Laplacian Filter) in different images using Matlab mathematical software in order to enhance images details

THE IMPORTANCE OF NEW MATERIALS DEVELOPMENT FOR INCREASING GAS TURBINES EFFICIENCY

This study shows the effects of new materials for gas turbines and techniques for blade coating. The implication on temperature limits of combustion chambers and consequently on high efficiency is also analyzed

Cajuína: como produzir com qualidade.

Anacardium occidentale L.; Os fundamentos; Linhas gerais de produção de cajuína em escala comercial; Descrição das etapas; A matéria-prima; O descastanhamento; Seleção; Pré-lavagem; Sanificação; Enxágue; Prensagem; Clarificação do suco; Filtrado; Enchimento das garrafas; Fechamento das garrafas; Tratamento térmico; Resfriamento; Alguns problemas e defeitos da cajuina; Turvação; Sedimentação após a estocagem prolongada; Falta de coloração característica; Cajuína sem gosto de caju; Cuidados e requisitos necessários com o recinto de processamento; Equipamentos básicos necessários.bitstream/CNPAT-2010/9247/1/Dc-095.pd

Transient Charging and Discharging of Spin-polarized Electrons in a Quantum Dot

We study spin-polarized transient transport in a quantum dot coupled to two ferromagnetic leads subjected to a rectangular bias voltage pulse. Time-dependent spin-resolved currents, occupations, spin accumulation, and tunneling magnetoresistance (TMR) are calculated using both nonequilibrium Green function and master equation techniques. Both parallel and antiparallel leads' magnetization alignments are analyzed. Our main findings are: a dynamical spin accumulation that changes sign in time, a short-lived pulse of spin polarized current in the emitter lead (but not in the collector lead), and a dynamical TMR that develops negative values in the transient regime. We also observe that the intra-dot Coulomb interaction can enhance even further the negative values of the TMR.Comment: 7 pages, 6 figures. Typos corrections corresponding to the published versio