ABSTRACT In this paper, an innovative method of impact tests at high temperature on sub-size Charpy V notched specimens is applied. The innovation lies in the method of heating the specimen, which is performed in situ on a Charpy impact machine type by alternating electrical current through the specimen. The specimens are heated in a few seconds (v=32 ºC/s) and held at the test temperature by an electrical circuit controlled by a thermocouple located on the specimen. Three types of steels are tested; with low, medium and high carbon content (perlitic). The impact energy was measured in the range of ductile fractures, from room temperature to 820 ºC, therefore, for the used steels the range of tested temperature contains the eutectoid phase transformation (AC1) and for the medium carbon steel is includes also has the limiting temperature γ+α / γ (AC3). It is concluded from tests analysis that the impact energy is sensitive to phase transformations. In turn, below AC1 the raise of temperature produced a progressive decrease in the energy absorbed up to a minimum at intermediate temperatures and then up to a maximum prior to phase transformation. Although the initial impetus for the development of this new technology was to estimate the brittle ductile transition that occurs at high temperature for some metal alloys, the wide range of temperatures, high test speed and simplicity of equipment, provides a new research tool for studies at different temperatures, especially on materials having embrittlement activation mechanisms at specific temperature intervals.

RESUMEN En el presente trabajo, se aplica un método innovador de ensayos de impacto en altas temperaturas sobre probetas Charpy de espesor reducido y entalla tipo V. La innovación reside en el método de calentamiento de la probeta, el cual es realizado in-situ sobre una máquina de impacto tipo Charpy por medio de corriente eléctrica alterna a través de la probeta. Las probetas son calentadas en pocos segundos (v=32 ºC/s) y mantenidas a la temperatura de ensayo por un circuito eléctrico controlado por un termopar ubicado sobre la probeta. Se ensayan tres tipos de aceros; de contenidos de carbono bajo, medio y alto (perlítico). La energía al impacto fue medida en el rango de fracturas dúctil, desde la temperatura ambiente hasta 820 ºC, por lo tanto para los aceros utilizados el rango de temperaturas ensayado contiene la transformación de fase eutectoide (AC1) y para el acero de medio carbono contiene además la temperatura del límite γ+α / γ (AC3). Se concluye a partir del análisis de los ensayos que la energía de impacto es sensible a las transformaciones de fase. A su vez, por debajo de AC1, al incrementar la temperatura se produce un descenso progresivo en la energía absorbida hasta alcanzar un mínimo a temperaturas intermedias y posteriormente un máximo previo a la transformación de fase. Si bien el ímpetu inicial para el desarrollo de esta nueva tecnología fue estimar la transición frágil dúctil que se produce a alta temperatura para algunas aleaciones metálicas, la amplia gama de temperaturas, elevada velocidad de ensayo y simplicidad del equipamiento, proveen una nueva herramienta de investigación para estudios a diferentes temperaturas, especialmente en materiales que presentan una activación de mecanismos de fragilización en intervalos de temperatura acotados.

ABSTRACT Fe-Al based alloys have a remarkable potential for high temperature structural applications, provided that the limitation of their low creep resistance is solved. Third element addition (Nb, Ti, Zr or Ta) has proven to per-form the task, at the expense of a low ductility. In previous works we have investigated ferritic alloys in the Fe-Al-V system with coherent precipitation of the L21 phase (Fe2AlV) in the A2 matrix. Among possible alloys, we chose the 76Fe-12Al-12V superalloy for filing a L21 precipitation with spherical morphology and void coalescence at high temperature. The new task is to find a fourth alloy element in order to increase the temperature equilibrium of the two phases A2+L21 field and consequently the maximum application tem-perature. Isothermal sections of the Fe rich corner on ternary Fe-Al-V and Fe-Al-Ti phase diagrams have similar phase fields. Besides, by comparing the formation energies between L21 intermetallics of Ti and V, it is expected a higher equilibrium temperature for the Fe2TiAl than for Fe2VAl. Therefore we select titanium as a possible 4th alloy element in the 76Fe-12Al-12V superalloy We show in this work that vanadium substi-tution by titanium slightly increases the temperature limit for the A2 + L21 phase field while cancelling the lattice misfit between matrix and precipitates for Ti content between 0.5 and 1 at. % and positively increasing it for Ti contents greater than 1 at. %. Besides, we demonstrate that coarsening rate is increased with Ti addi-tion and morphology is modified from spherical to cubic.

RESUMEN Las aleaciones basadas en Fe-Al tienen un potencial considerable como materiales para aplicaciones estructurales en altas temperaturas. Sin embargo, su insuficiente resistencia a la termofluencia ha sido un obstáculo para su aplicación. La adición de un tercer aleante (Nb, Ti, Zr ó Ta) ha conseguido aumentar su resistencia a altas temperaturas, pero a costa de una baja ductilidad. En trabajos previos y con el fin de resolver estas deficiencias, investigamos aleaciones ferríticas de Fe-Al-V con precipitación coherente de la fase L21 (Fe2AlV) sobre una matriz A2. Entre las posibles aleaciones, por presentar precipitados L21 de morfología esférica y sin efecto de coalescencia en alta temperatura, seleccionamos la superaleación 76Fe-12Al-12V. Buscamos ahora un cuarto aleante capaz de incrementar la temperatura de coexistencia del campo de dos fases A2+L21 y en consecuencia la máxima temperatura de aplicación. Encontramos que las secciones isotérmicas del rincón rico en Fe de los diagramas de fases ternarios Fe-Al-V y Fe-Al-Ti poseen campos de fases similares. Además, la relación entre las energías de formación calculadas para los intermetálicos L21 con Ti y V, permite predecir una temperatura de equilibrio mayor para el Fe2TiAl que para el Fe2VAl. Por lo tanto, seleccionamos al Ti como posible 4to aleante en la superaleación 76Fe-12Al-12V. En este trabajo mostramos que la sustitución del vanadio por titanio incrementa levemente la temperatura máxima de existencia del campo A2 + L21, además el desajuste de red matriz/precipitado es anulado para un contenido de Ti entre 0,5 y 1 % atómico e incrementado en forma positiva a mayores porcentajes de Ti. Analizamos por otro lado la cinética de engrosamiento de los precipitados L21 hallando que la velocidad aumenta con el agregado de Ti y la morfología se modifica de esférica a cúbica.

ABSTRACT The use of nuclear reactor as a source of electric energy has been extended and consolidated during the second half of last century and the beginnings of XXI century. The continuity of this resource relies on the reliability and security of nuclear plants, requiring the improvement of all features related to their operation. Among them, the structural elements integrity that depends strongly on the mechanical stability of protective oxides must be taken into account. Zircaloy-4 (zirconium based alloy with Sn, Fe and Cr additions) is used for the coolant channels at CNA I and CNA II plants. However, this alloy suffers corrosion problems which have caused, for example, the replacement of coolant channels at CNA I in 1988. In this work we analyze from functional density theory (DFT) the properties of low index hexagonal Zr surface and of the experimentally observed (001) tetragonal ZrO2 surface. Our results predict Zr (1120) and O terminated ZrO2(001) with Zr subsurface, as the surfaces with the lowest superficial energy. The Zr(1010) surface exhibits the most inhomogeneous charge density. This feature could favor oxygen adsorption and then the oxide growth, in agreement with the experimentally observed Zr(1010)/ZrO2(001) interface.

RESUMEN El uso de los reactores nucleares como fuente de energía se ha extendido y consolidado en la segunda mitad del siglo XX y en los inicios de este siglo XXI. La continuidad de este recurso depende en gran medida de que las plantas nucleares sean cada vez más seguras y confiables, lo cual implica un mejoramiento de todos los aspectos relacionados con su operación. Entre ellos se cuenta la integridad de los elementos estructurales, que depende fuertemente de la estabilidad mecánica de los óxidos protectores. En las centrales CNA I y CNA II el Zircaloy-4 (aleación base Zr con adiciones de Sn, Fe and Cr) se utiliza en los canales refrigerantes. Sin embargo, esta aleación presenta problemas de corrosión que, por ejemplo, motivaron el reemplazo de los canales refrigerantes de CNA I en 1988. En este trabajo analizamos desde la teoría de la funcional densidad (DFT) las propiedades de superficies de bajo índice de Zr hexagonal y de la superficie (001) observada experimentalmente en circonia tetragonal. Nuestros resultados predicen a la superficie libre de Zr (1120) y a la de ZrO2 (001) terminada en O con subsuperficie de Zr como las más estables. Además encontramos que las superficies Zr(1010) tienen la mayor inhomogeneidad de la distribución de carga, lo que favorecería el crecimiento del óxido. Esta observación coincide con la evidencia experimental, que indica que la interfaz observada del óxido protector es Zr(1010)/ZrO2(001).

ABSTRACT Once the stable structure of point defects and concentrations of defects in thermal equilibrium were obtained for each composition of Al of the compound UAl4, we identified, in this work, the more likely mechanisms for Al mobility in UAl4, and we analyzed transition states in the diffusion of Al in UAl4 by the Nudged Elastic Band (NEB) method implemented in VASP code. Using first principles methods, we have calculated the compound total energy variation according to the migration path of aluminum, in order to find the saddle points between two equilibrium positions and to obtain the minimum migration energy path. This allowed us to propose two most likely mechanisms for the diffusion of Al atoms in the Al-rich side of the intermetallic: antistructural bridge mechanism (ASB) and vacancy mechanism between first neighbors aluminum Al1 sites (NN). When calculating the energy of migration for both mechanisms we estimated both activation energies. The activation energy of ASB mechanism was lower than the NN mechanism but the first mechanism was dismissed for two reasons: on one hand, the activation energy is half the experimentally observed and on the other hand, according to literature, the ASB mechanism needs a threshold antisite concentration relatively high so that the diffusion path results a long-range one. Based on all results and discussions we propose that the aluminum diffusion mechanism occurs in UAl4 by means of NN mechanism with an activation energy of 1.90 eV which compares relatively well with the experi-mentally observed value of 2.06 eV, or the value of 2.17 eV previously obtained using a semi-empirical model.

RESUMEN Obtenida la estructura de defectos puntuales estables y las concentraciones de defectos en equilibrio térmico para cada composición de Al del compuesto UAl4 previamente, identificamos en este trabajo los mecanismos más probables de difusión de Al en UAl4, y analizamos los estados de transición en la difusión de Al en UAl4 mediante el método Nudged Elastic Band (NEB) implementado en el código VASP. Calculamos utilizando métodos de primeros principios la variación de la energía total del compuesto en función del camino de difusión del aluminio, con el objetivo de encontrar los puntos de ensilladura para pasar entre dos posiciones de equilibrio y así obtener el camino de mínima energía para la difusión. Esto nos permitió proponer dos mecanismos más probables para la difusión de átomos de Al en el lado rico en Al del intermetálico: mecanismo de puente anties-tructural (ASB) y mecanismo de vacancia entre sitios primeros vecinos de aluminio Al1 (NN). Al calcular la energía de migración para ambos mecanismos conseguimos estimar ambas energías de activación. La energía de activación del mecanismo ASB resultó menor que la del mecanismo NN pero el primer mecanismo fue des-estimado por dos motivos: por un lado la energía de activación es la mitad de la observada experimentalmente y por otro lado, siguiendo la literatura, el mecanismo ASB necesita una concentración umbral de antisitios relati-vamente alta para que el camino de difusión resulte de largo alcance. En base a todos los resultados y discusiones realizados, proponemos que el mecanismo de difusión de aluminio en UAl4 ocurre por el mecanismo NN con una energía de activación de 1.90 eV que compara relativamente bien con el valor 2.06 eV observado experimentalmente, o con el valor 2.17 eV obtenido previamente utilizando un modelo semi-empírico.

Abstract The mechanical stability of oxides formed on metallic alloys is a key concern in the determination of component susceptibility to the medium in contact and the applicability of the alloy to high temperatures and other extreme conditions. In this context, the energy of adhesion is a key parameter. Density functional Theory (DFT) and other atomistic methods are fundamental tools in the determination of this quantity for Metal/Oxide interfaces. In this paper Fe(BCC) / Magnetite interface is assessed within the DFT approach. This system is of general interest, given that magnetite (Fe3O4) is the oxide in direct contact with the metal under generalized corrosion and for a wide range of conditions. Moreover, it has been demonstrated that passive films on iron alloys exhibit similar structural properties. Magnetite is an inverse spinel with Fd3m structure, while Iron has a BCC crystal structure. The interface Fe3O4[001]-Fe[001] is modeled. The orientation relationship experimentally observed for this interface is Fe3O4[100]||Fe[110]. In the (001) direction, atomic layers with compositions FeO2 and Fe are alternated. Here only the Fe termination is treated, as it has been proved that it constitutes the most stable interface [1,2]. DFT is used to calculate the work needed to relatively slide the oxide and metal surfaces in reference to the principal directions of the interface. Hence, it is possible to calculate the interface potential according to the model by WEI and HUTCHINSON [3]. This potential can be used for construction of meso scale models of the interface for a complete study of its properties.

RESUMEN La estabilidad mecánica de los óxidos formados sobre las aleaciones de uso industrial, y su adhesión al sustrato metálico es de vital importancia para determinar la susceptibilidad de las aleaciones a los medios en contacto y la aplicabilidad en condiciones de alta temperatura u otras condiciones extremas. En este contexto, la energía de adhesión es uno de los parámetros principales a determinar. Los métodos atomísticos como la Teoría del Funcional de la Densidad (DFT) se presentan como una herramienta fundamental para calcular este parámetro en interfases Oxido/Metal. En este trabajo se estudia con esta técnica la interfaz Fe(BCC)/Magnetita. El interés en este sistema radica en que se ha visto que la magnetita (Fe3O4) es el óxido en contacto con el metal en condiciones de corrosión generalizada, e incluso las capas de óxido pasivante pueden tener cierta similitud con esta desde el punto de vista estructural. Dado que la magnetita es una espinela inversa de estructura cristalina Fd3m y el hierro posee una estructura BCC, se modela la interfaz Fe3O4[001]-Fe[001] teniendo en cuenta que experimentalmente se observa la relación de orientaciones Fe3O4[100]||Fe[110] para la misma. A lo largo de la dirección [001] en el óxido se alternan los planos de composición FeO2 y Fe, aunque aquí solo se trata la terminación Fe de la magnetita, ya que se ha demostrado que forma la interfaz más estable [1,2]. Se utiliza DFT para calcular el trabajo necesario para deslizar las superficies en relación a las direcciones principales de la interfaz, para luego calcular el potencial interfacial en función de las coordenadas generalizadas de la misma según el modelo de WEI y HUTCHINSON [3]. Este potencial puede ser utilizado en modelos de meso escala de la interfaz, por ejemplo para el cálculo de la tenacidad de la misma.

Methodologies and procedures used in dietary surveys have been widely developed with the aim of evaluating the nutritional status of a population. However, beverages are often either disregarded at national and international assessment of nutrients intake or poorly mentioned. Moreover, there is no standardized questionnaire developed as a research tool for the evaluation of beverages intake in the general population. Moreover, the contribution of different beverages to macronutrients intake is rarely provided. The latter in the context of a continuous expansion and innovation of the beverages market in Spain. Therefore, the main goal of the present study was to evaluate non-alcoholic and alcoholic beverages macronutrients contribution in the ANIBES study in Spain (9-75 years old). As expected, those contributed to dietary macronutrient intake mainly as total carbohydrates and sugar. The contribution to other macronutrients (proteins and lipids) by the beverage groups was of much less importance. For non-alcoholic beverages, contribution to carbohydrates was much higher in younger populations (children: 10.91 ± 9.49%, mean ± SD for boys and 9.46 ± 8.83% for girls; adolescents: 11.97 ± 11.26% for men and 13.77 ± 10.55% in women) than in adults: 9.01 ± 9.84% for men and 7.77 ± 8.73% in women. Finally, a much lower contribution was observed in the elderly: 4.22 ± 6.10% for men and 4.46 ± 6.56% for women. No sex differences, however, across all age groups were found. Results for sugar contribution showed a similar trend: children (23.14 ± 19.00% for boys and 19.77 ± 17.35% for girls); adolescents (28.13 ± 24.17% for men and 29.83 ± 21.82% in women); adults 20.42 ± 20.35% for men and 16.95 ± 17.76% in women, p ≤ 0.01; and elderly: 14.63% ± 9.97 for men and 9.33 ± 12.86% in women. The main contribution corresponded to sugared soft drinks, juices and nectars, more relevant and significant in the younger populations. As for alcoholic beverages, the contribution of macronutrients to the total diet is low for carbohydrates and sugar. The main contribution of this group, as expected, is alcohol, being higher from low alcohol content beverages, and in men vs women (p ≤ 0.001).

Objectives: To describe the evolution of non-alcoholic and alcoholic beverages consumption in the Spanish households from the 60's to nowadays. Methods: This study is based on beverages and food consumption in Spanish households; the data sample consisted of consumption and distribution data, obtained from the Household Budget Survey (HBS) since 1964 to 1991 and from the Food Consumption Survey (FCS) since 2000 to 2014, in collaboration with the Spanish Nutrition Foundation (FEN). Results: In 2014 the average consumption of non-alcoholic beverages was 332 g/person/day, whereas alcoholic beverages consumption represented 72.6 g/person/day. Consumption of non-alcoholic beverages has increased 721% (1964: 46 g/person/day; 1991: 96 g/person/day; 2000: 240 g/person/day and 2014: 332 g/person/day), whereas alcoholic beverages consumption has decreased roughly a 50% (1964: 145 g/person/day; 1991: 113 g/person/day; 2000: 78.4 g/person/day and 2014: 72.6 g/person/day). The most consumed alcoholic beverage in 2014 was beer (41.3 g/day), followed by wine (23.0 g/day). Regarding non-alcoholic beverages, the most consumed was water (144 g/day), followed by cola (ordinary: 30.7 g/day and diet: 20.5 g/day). According to Spanish regions, in 2014 non-alcoholic beverages were the most consumed in the islands (Balearic Islands 521 grams/person/day; Canary Islands 515 grams/person/day), as it was in the nineties (Balearic Islands 148 grams/person/day and Canary Islands 281 grams/person/day). However in 1980-81 the largest consumption of alcoholic beverages was that of Galicia, 408 g/person per day, and the lower in the Canary Islands, 63 g/person per day. In 2014, Murcia and Andalucía represented the regions with the highest consumption of alcoholic beverages. In 2014, alcoholic beverages provided roughly 1.89% of the total energy and 1.47% of sugars, whereas non-alcoholic beverages provided 3.28% of energy and 15.72% of sugars and, in 2000, alcoholic beverages contributed 2.29% of the energy and 1.47% of sugars and non-alcoholic drinks provided 3.76% of the energy and 22.7% of sugars. Conclusion: There have been significant changes in the eating patterns at the Spanish homes, especially regarding beverages consumption, over the last five decades. In general, a higher consumption and variety for non-alcoholic drinks has occurred, especially in the islands. In parallel, a decline in alcoholic beverages consumption has been clearly observed.

Introduction: Nutrition education contributes to children's understanding and practice of healthy lifestyles behaviors. Having a well hydration status is an essential topic, especially since children are a vulnerable population who are much more prone to dehydration than adults are. The approval of the Report on the European Gastronomic Heritage: Cultural and Educational Aspects in 2014 served as starting point to work on innovative audio-visual and multimedia materials for children. The Spanish Nutrition Foundation (FEN) and the Royal Academy of Gastronomy (RAG), in collaboration with the Ministry of Education, Culture and Sport in Spain (MECD), developed educational videos for schoolchildren to learn about food, nutrition and gastronomy, specially, the importance of being hydrated. Objectives: To develop a serial of videos for children between 3 and 9 years old with nutrition and cooking lessons to be used as educational resources in the official curricula. Methods: Fourteen chapters related to food, nutrition, gastronomy, physical activity and hydration to be used to record videos were designed and tested. A nutritionist, a chef and two puppets were the main characters acting in the videos. Results: The chapters were assembled in nine videos that included five sections: introduction, video lesson, recipes -in case of hydration, recipes with different water content foods were recorded-, what have you learnt and check your knowledge. A summary of the new educational material was officially presented at the Spain Pavilion during the Expo Milano 2015. Moreover, they are included as education tool for teachers in the new PANGEI Programme (Food, Nutrition and Gastronomy for Infantile Education) conjointly launched by FEN, RAG and MEDC. Conclusion: Taste workshops are useful as innovative nutrition education tools to reinforce language, listening and motor skills as well as food and nutrition concepts, and specially, the importance of being well hydrated.

Objectives: To determine whether weather conditions explain the North-South gradient in multiple sclerosis (MS) mortality described in Spain. Methods: The age-adjusted MS mortality rate by Spanish provinces from 1975 to 1998 was correlated with several climatic variables. Results: MS mortality was negatively correlated with minimum, average and maximum temperatures, the mean number of hours of sunshine, and the mean number of sunny days. A positive correlation was found with the average amount of rain. Most correlations disappeared after adjusting by latitude. However, MS mortality was associated with latitude after adjusting by climatic factors. Conclusions: The North-South gradient in MS mortality in Spain cannot be fully explained by weather differences. Therefore, other hypotheses are required to explain this association.

Objetivo: Comprobar si las variables meteorológicas justifican el gradiente norte-sur en la mortalidad por esclerosis múltiple (EM) en España. Métodos: La tasa de mortalidad por EM ajustada por edad en cada provincia de 1975 a 1998 se correlacionó con la media anual de diferentes variables meteorológicas. Resultados: Las temperaturas mínima, media y máxima, el número medio de horas de sol y el número de días soleados se correlacionaron negativamente con la mortalidad por EM, mientras que la cantidad de lluvia se correlacionó positivamente con la EM. La mayor parte de las correlaciones desaparecen al ajustar por latitud. En cambio, la mortalidad por EM está asociada con la latitud incluso después de ajustar por los factores meteorológicos. Conclusión: El gradiente norte-sur en la mortalidad por EM en España no puede explicarse completamente por factores meteorológicos. Son necesarias otras hipótesis para justicar esta asociación.

Objectives: To determine whether weather conditions explain the North-South gradient in multiple sclerosis (MS) mortality described in Spain. Methods: The age-adjusted MS mortality rate by Spanish provinces from 1975 to 1998 was correlated with several climatic variables. Results: MS mortality was negatively correlated with minimum, average and maximum temperatures, the mean number of hours of sunshine, and the mean number of sunny days. A positive correlation was found with the average amount of rain. Most correlations disappeared after adjusting by latitude. However, MS mortality was associated with latitude after adjusting by climatic factors. Conclusions: The North-South gradient in MS mortality in Spain cannot be fully explained by weather differences. Therefore, other hypotheses are required to explain this association.

Objetivo: Comprobar si las variables meteorológicas justifican el gradiente norte-sur en la mortalidad por esclerosis múltiple (EM) en España. Métodos: La tasa de mortalidad por EM ajustada por edad en cada provincia de 1975 a 1998 se correlacionó con la media anual de diferentes variables meteorológicas. Resultados: Las temperaturas mínima, media y máxima, el número medio de horas de sol y el número de días soleados se correlacionaron negativamente con la mortalidad por EM, mientras que la cantidad de lluvia se correlacionó positivamente con la EM. La mayor parte de las correlaciones desaparecen al ajustar por latitud. En cambio, la mortalidad por EM está asociada con la latitud incluso después de ajustar por los factores meteorológicos. Conclusión: El gradiente norte-sur en la mortalidad por EM en España no puede explicarse completamente por factores meteorológicos. Son necesarias otras hipótesis para justicar esta asociación.