Parameter characterization of HTPEMFC using numerical simulation and genetic algorithms

This paper develops a novel approach to the parameterisation of high temperature exchange membrane fuel cells (HTPEMFC) with limited and non-invasive measurements. The proposed method allows an effective identification of electrochemical parameters for three-dimensional fuel cell models by combining computational simulation tools and genetic algorithms. To avoid each evaluation undertaken by the optimisation method involving a complete computational simulation of the 3D model, a strategy has been designed that, thanks to an iterative process, makes it possible to decouple the fluid dynamic resolution from the electrochemistry one. Two electrochemical models have been incorporated into these tools to describe the behaviour of the catalyst layer, Butler-Volmer and spherical aggregate. For each one, a case study has been carried out to validate the results by comparing them with empirical data in the first model and with data generated by numerical simulation in the second. Results show that, from a set of measured operating conditions, it is possible to identify a unique set of electrochemical parameters that fits the 3D model to the target polarisation curve. The extension of this framework can be used to systematically estimate any model parameter in order to reduce the uncertainty in 3D simulation predictions. © 2021 The Author(s

Evolución geodinámica de la fosa del Empordà y las Sierras Transversales

The Emporda basin, together with the half graben system of the Sierras Transversales, form a segment of the European Rift, which is defined here by the NW-SE-trending fault system of northeastern Catalonia.The study area, which partially includes the Sierras Transversales and the southem margin of the Emporda basin, is internally structured by normal faults with listric geometry. Those with measured dip slips of about 1,000 meters are here called main faults; those located in the hanging walls of the main ones are called minor faults, and their dip slips are, at least, lesser in one order of magnitude. The hanging walls of the main faults hold half graben basins, with a sedimentary infill mainly neogene in age in the Emporda, and of quaternay age in the Sierras Transversales. Both areas are geologically bounded by the Camós-Celra fault. This rift segment is also characterized by the occurence of numerous volcanic emission centres. The timing of activity and burial of each fault, constrained by the ages of the associated sediments and vulcanism, suggest a piggy-back sequence of propagation from Miocene to recent times. The geological cross-section constructed from surface data, allowed us the elaboration of a geometric model in clepth for the whole fault system, usiug the inclined shear method. The calculated extension from this method gives us a value of B=1.27. On the other han4 the very high calculated magma ascent rates strongiy constrain the structure in the footwall (crust); subsequently, high angle discontinuities favouring a very fast magmatic ascent have to be definied. These discontinuities would form two imbricate systems (extensional duplexes), with a roof detachment coinciding with the floor detachment of the shallow fault system and a floor detachment located in the MOHO discontinuity. A similar crustal structuration is observed in the neighbouring segment of the Gulf of Lions

Macroscopic heat release in a molecular solar thermal energy storage system

The development of solar energy can potentially meet the growing requirements for a global energy system beyond fossil fuels, but necessitates new scalable technologies for solar energy storage. One approach is the development of energy storage systems based on molecular photoswitches, so-called molecular solar thermal energy storage (MOST). Here we present a novel norbornadiene derivative for this purpose, with a good solar spectral match, high robustness and an energy density of 0.4 MJ kg -1 . By the use of heterogeneous catalyst cobalt phthalocyanine on a carbon support, we demonstrate a record high macroscopic heat release in a flow system using a fixed bed catalytic reactor, leading to a temperature increase of up to 63.4 °C (83.2 °C measured temperature). Successful outdoor testing shows proof of concept and illustrates that future implementation is feasible. The mechanism of the catalytic back reaction is modelled using density functional theory (DFT) calculations rationalizing the experimental observations

The projects on geological cartography of the Geological Survey of Catalonia

Since the Gravimetric Map on a scale of 1/500 000 was published in 1987, the Geological Survey of Catalonia (SGC) published in 1989 the Geological and the Aeromagnetic maps on a scale of 1/250 000. The publications of the Hydrogeological map on a scale of 1/250 000 (1992) and a crustal-scale cross-section on a scale of 1/200 000 (1993) followed the first maps. Currently the Survey is developping a project of regional geological mapping on a scale of 1/25 000 wich aim is to cover the entire area of Catalonia (about 31 879 sq.km), which is included into 301 sheets. The Survey is also involved in a project of detailed geological mapping of the highly populated, neighbouring area of Barcelona (about 3 180 sq. km.) on a scale of 1/10 000. Other projects the Survey is going on are the Structural Map on a scale of 1/250 000 and a new edition of the Geological Map at the same scale. Either the hardware and software facilities, the topographic bases, and the edition and publication works are supplied by the Cartographic Institute of Catalonia (ICC). The aim of this paper is to give general information about these project