6 documents found, page 1 of 1
Thermal aging effects on the microstructure of Nb-bearing nickel based superall...
Albuquerque, Victor Hugo Costa de; Silva, Cleiton Carvalho; Normando, Paulo Garcia; Moura, Elineudo Pinho de; Tavares, João Manuel R.S.Secondary phases such as Laves and carbides are formed during the final stages of solidification of the nickel based superalloy Inconel 625 coatings deposited during the gas tungsten arc welding (GTAW) cold wire process. However, when aged at high temperatures, other phases can precipitate in the microstructure, like the c00 and d phases. The aim of this work was to evaluate the different phases formed during t...
Automatic microstructural characterization and classification using artificial ...
Nunes, Thiago M.; Albuquerque, Victor Hugo Costa de; Papa, João Paulo; Silva, Cleiton C.; Normando, Paulo Garcia; Moura, Elineudo Pinho deSecondary phases such as Laves and carbides are formed during the final solidification stages of nickel based superalloy coatings deposited during the gas tungsten arc welding cold wire process. However, when aged at high temperatures, other phases can precipitate in the microstructure, like the c00 and d phases. This work presents a new application and evaluation of artificial intelligent techniques to classif...
Characterization of cast iron microstructure through fluctuation and fractal an...
Moura, Elineudo Pinho de; Normando, Paulo Garcia; Gonçalves, Lindberg Lima; Kruger, S.E.This work aims at evaluating the performance of pattern recognition methods in the identification of different microstructures presented by cast iron, namely, lamellar, vermicular and nodular microstructures, through the statistical fluctuation and fractal analyses of backscattered ultrasonic signals. The signals were obtained with a broad band ultrasonic probe with a central frequency of 5 MHz. The statistical...
Ultrasound, eddy current and magnetic Barkhausen noise as tools for sigma phase...
Normando, Paulo Garcia; Moura, Elineudo Pinho de; Souza, José A.; Tavares, Sérgio Souto Maior; Padovese, Linilson RodriguesSigma phase is a deleterious one which can be formed in duplex stainless steels during heat treatment or welding. Aiming to accompany this transformation, ferrite and sigma percentage and hardness were measured on samples of a UNS S31803 duplex stainless steel submitted to heat treatment. These results were compared to measurements obtained from ultrasound and eddy current techniques, i.e., velocity and impedan...
Microstructure identification via detrended fluctuation analysis of ultrasound ...
Normando, Paulo Garcia; Nascimento, Romão Sampaio do; Moura, Elineudo Pinho de; Vieira, André de PinhoWe describe an algorithm for simulating ultrasound propagation in random one-dimensionalmedia,mimicking differentmicrostructures by choosing physical properties such as domain sizes andmass densities from probability distributions. By combining a detrended fluctuation analysis (DFA) of the simulated ultrasound signals with tools from the pattern-recognition literature, we build a Gaussian classifier which is ab...
Spatial interference alignment under realistic scenarios
Normando, Paulo GarciaDue to the rapid growth and the aggressive throughput requirements of current wireless networks, such as the 4th Generation (4G) cellular systems, the interference has become an issue that cannot be neglected anymore. In this context, the Interference Alignment (IA) arises as a promising technique that enables transmissions free of interference with high-spectral efficiency. However, while recent works have foc...