CORROSION ATMOSFÉRICA MARINA DE ACEROS AL CARBONO

Ciclo de Conferencias. 50 Aniversario Revista de MetalurgiaLa investigación fundamental en corrosión atmosférica marina de aceros al carbono es un campo científico relativamente joven que presenta grandes lagunas de conocimiento. La formación de akaganeita como producto de corrosión del acero en atmósferas marinas conduce a un incremento notable de la velocidad de corrosión. En la conferencia se abordan las siguientes cuestiones: • La formación y transporte del aerosol marino (salinidad atmosférica). • Condiciones ambientales necesarias para la formación de akaganeita. • Caracterización de la akaganeita en los productos de corrosión mediante XRD, SEM/EDS, TEM/ED, Espectroscopía Mössbauer y SEM/MicroRaman. • Exfoliación de las capas de herrumbre formadas en atmósferas marinas muy agresivas. • Mecanismos de corrosión. • Predicción del comportamiento a largo plazo del acero al carbono. • Comportamiento de aceros patinables en atmósferas marinas. La investigación de campo se lleva a cabo en el Parque Eólico de Cabo Vilano (Camariñas, Galicia) en un amplio rango de salinidades atmosféricas.Revista de MetalurgiaN

The Deployment of Young Readers´ Visual Attention across Orthographic Strings: The Influence of Stems and Suffixes

Published online: 27 Apr 2020The goal of the paper was to investigate whether morphological units – stems and suffixes – influence orthographic processing by modulating visual attention demands to the task. Orthographic processing was measured with a visual one-back task requiring letters to be detected within pseudowords not including stems/suffixes, or containing real stems or real suffixes. Fourth grade children (between 9.5 and 10.5 years old) who read in a transparent orthography of a morphologically rich and agglutinative language (Basque) were tested. The results showed that the presence of morphemes in the strings did not improve letter detection performance though it slightly modulated the distribution of visual attention, showing a bias toward the processing of central letters in the presence of a stem. We suggest that the presence of highly regular and recurrent structures prioritizes stem identification, which when achieved, reduces visual attention deployment across the remaining letters.The authors acknowledge financial support from the Basque Government (PRE_2015_2_0049 to A. A.), the European Research Council (ERC-2011-ADG-295362 to M.C.), the Spanish Ministry of Economy and Competitiveness (PSI20153653383P to M.L., PSI20153673533R to M. C, and SEV-2015-490 awarded to the BCBL through the “Severo Ochoa Program for Centers/Units of Excellence in R&D”). This research is also supported by the Basque Government through the BERC 2018-2021

Ionization probability of the hydrogen atom suddenly released from confinement

The problem of the stability of a confined atom when it is extracted from the confining cavity has been investigated, modeled by a spherical hard wall potential. The ionization probability when the atom is released from confinement has been obtained. The dependence of the ionization probability on the confinement radius and on the quantum numbers of the initial confined state has been studied. The probability density function of the ionization energy of the ejected electron has been obtained for the different cases considered. The oscillatory structure of this distribution function, with a principal maximum located in the neighborhood of the energy of the initial state and minima very close to zero has been elucidated. The sudden approximation has been applied and the analytic continuation method has been used to calculate the different stationary states

Ionization and excitation probabilities of a hydrogen atom suddenly released from penetrable confinement

The problem of the stability of the hydrogen atom when it is released from a confining environment is studied. The stability is analysed in terms of excitation and ionization probabilities of the final state for different initial states. A spherical confining cavity of finite barrier height v0 with inner radius r0 and thickness _ with the nuclear position at its center has been considered. The ionization probability presents different sharply peaked, non-symmetric local maxima as a function of the confinement size. This behaviour is related to the energy of the initial confined state that presents several maxima and minima in a kink-like structure as a function of the confinement size. The physical origin of these effects has been explained in terms of tunnelling and re-tunnelling of the atomic states. The sudden approximation and the analytic continuation method have been employed

Effects of size on the spectrum and stability of a confined on-center Hydrogen atom

In this work we studied the problem of the stability of confined atoms when they are released from confinement. We analyzed the confined Hydrogen atom inside a cage modelled by a square-well potential, in particular the effects of size on the energy and the electronic structure of the confined atom, by considering different internal radii of the confining cage. Starting from the confined wave function, we clarified the effect on the probability transition between different confined states, and characterized the stability of the atom when released from in term of both, the ionization probability and the transition probability to a bound state of the free atom. The values of the different atomic properties calculated present oscillations when they are studied as a function of the size of the confining cage. This behaviour can be explained in terms of the shell structure of the atom

Cross-linguistic transfer in bilingual reading is item specific

First published online: 26 April 2021The grain size of orthographic representations prompted by a consistent orthography (like Spanish or Basque) increases if reading is simultaneously learned in another language with an inconsistent orthography (like French). Here, we aimed to identify item properties that trigger this grain-size accommodation in bilingual reading. Twenty-five French–Basque and 25 Spanish–Basque bilingual children attending Grade 3 read Basque words and pseudowords containing “complex” letter clusters mapping to one sound in French but several sounds in Basque or Spanish, and “simple” letter clusters mapping to the same sound structure in all three languages. Only French speaking children read “complex” Basque words faster than “simple” ones, suggesting that they accessed multi-letter “French” units to boost lexical processing. A negative complexity effect was found for pseudowords across groups. We discuss the existence of flexible cross-linguistic transfer in bilingual reading, proposing that the grain size of orthographic representations adjusts to item-specific characteristics during reading.This research was support by the Basque Government (BERC 2018-2021 program to BCBL, and PIBA_2018_1_0029 to C.D.M.), the H2020 European Research Council program (ERC-2018-COG-819093 to C.D.M.) and Spanish Ministry for Science and Innovation (PSI2017-82941-P and RED2018-102615-T to C.D.M., RTI2018-096242-B-I00 to M.L., RYC-2015-17356 to M.L., and SEV-2015-0490 to the BCBL)

Atmospheric Corrosion Studies in a Decommissioned Nuclear Power Plant

Metallic corrosion progresses at a very low rate at room temperature in a perfectly dry atmosphere and for practical purposes may be ignored, but on humid surfaces is a very relevant phenomenon. The mechanism is electrochemical, with an electrolyte constituted by an extremely thin moisture film of just a few monolayers or an aqueous film of hundreds of microns in thickness due, for instance, to rain or dew (Rozenfeld, 1972; Barton, 1976; Feliu and Morcillo, 1982; Kucera & Mattson, 1986; Costa et al., 2006). A considerable part of the damage that atmospheric corrosion causes to structures and equipment may be attributed to the condensation of humidity as a result of periodic cooling of the air. The formation of dew depends on the relative humidity (RH) of the air and the change in the metal surface temperature. The drier the atmosphere, the more the temperature must fall in order for humidity to condense; while at high RH a slight drop in temperature can lead to the saturation in humidity of the atmosphere. The fraction of time in which an atmosphere presents a high RH level has been shown to be a good indicator of its potential aggressivity.Peer reviewe

Looking back on contributions in the field of atmospheric corrosion offered by the MICAT ibero-american testing network

The Ibero-American Map of Atmospheric Corrosiveness (MICAT) project was set up in 1988 sponsored by the International Ibero-American programme >Science and Technology for Development (CYTED)> and ended in 1994 after six years of activities. Fourteen countries were involved in this project: Argentina, Brazil, Chile, Colombia, Costa Rica, Cuba, Ecuador, Mexico, Panama, Peru, Portugal, Spain, Uruguay, and Venezuela. Research was conducted both at laboratories and in a network of 75 atmospheric exposure test sites throughout the Ibero-American region, thus considering a broad spectrum of climatological and pollution conditions. Although with its own peculiarities, the project basically followed the outline of the ISOCORRAG and ICP/UNECE projects, with the aim of a desirable link between the three projects. This paper summarizes the results obtained in the MICAT project for mild steel, zinc, copper, and aluminum specimens exposed for one year in different rural, urban, and marine atmospheres in the Ibero-American region. Complementary morphological and chemical studies were carried out using scanning electron microscopy (SEM) coupled with energy dispersive spectrometry (EDS), X-ray diffraction (XRD), and fourier transform infrared Spectroscopy (FTIR) techniques, in order to correlate climatic and atmospheric conditions and properties of the corrosion products. © 2012 M. Morcillo et al.Peer Reviewe

On- and off-center helium atom in a spherical multilayer quantum dot with parabolic confinement

The ground state energy of a helium atom inside a spherical multilayer quantum dot as a function of the atomic impurity location inside the quantum dot has been calculated. The multilayer quantum dot is modeled by a core/shell/well/shell structure using a parabolic confinement. The Configuration Interaction method and the Diffusion Monte Carlo have been used to solve the Schrödinger equation. Results obtained showed that the lowest energy configuration depends on the size of the different layers of the quantum dot and agreement between Configuration Interaction and Diffusion Monte Carlo results indicates that the Configuration Interaction approach used here would be suitable to compute excited states of this system