“Evolved Materials and Innovative Design for High Performance, Durable and Reliable SOFC Cell and Stack” Presentation and Status of the European Project EVOLVE

Beyond the state of the art, EVOLVE aims at the development of a new cell architecture for SOFC, combining benefits of existing Anode Supported (high power density, lifetime) and Metal Supported cell (redox stability) architectures, while limiting the issue of sulphur poisoning by using enhanced perovskite anode materials. The core component is based on a composite anode substrate made of porous Alumina forming alloy combined with an electron conducting oxide ceramic, without having Nickel as structural component. A first Anode/Electrolyte assembly based on a NiCrAl foam and La0,1Sr0,9TiO3-α has been produced by means of Vacuum Plasma Spraying, showing the feasibility of this cell concept. With a requirement of a low temperature process, the manufacturing of the electrolyte layer remains the key challenge. Work is under progress for the manufacturing and testing of the first full prototype

Confidence Bounds for the Estimation of the Volume Phase Fraction from a Single Image in a Nickel Base Superalloy

We propose an image-based framework to evaluate the uncertainty in the estimation of the volume fraction of specific microstructures based on the observation of a single section. These microstructures consist of cubes organized on a cubic mesh, such as monocrystalline nickel base superalloys. The framework is twofold: a model-based stereological analysis allows relating two-dimensional image observations to three-dimensional microstructure features, and a spatial statistical analysis allows computing approximate confidence bounds while assessing the representativeness of the image. The reliability of the method is assessed on synthetic models. Volume fraction estimation variances and approximate confidence intervals are computed on real superalloy images in the context of material characterizatio

Investigation of Advanced Cathode Contacting Solutions in SOFC

Contacting solutions for air electrode in Solid Oxide Cells stacks often implement a ceramic paste made of electronic conducting perovskite, comparable or same as the electro-active material. This contacting layer, is applied in a green state by wet-powder-spray or screen-printing, and in situ fired during stack commissioning. The low level of necking between ceramic particles causes increased ohmic losses. Moreover the shrinkage usually observed during long term operation in temperature of this layer, due to sintering effect, lead to cracks and contact losses which hinder the cell performance. Increasing cell’s footprint, performance and lifetime at the stack level requires appropriate contacting solution. In this paper we reports the investigation of a new advanced monolithic contacting solution, easy to handle, soft and flexible, highly porous and highly conductive. Two different compositions have been investigated, with respect of their compatibility with Crofer (SEM, XRD). In addition, solid oxide cells contacted with this solution as well as with a ceramic paste have also been electrochemically tested up to 1000 hours in order to compare and assess the impact of this contacting solution on cell’s performance. Results will be presented and discussed

Enhancing Access to Legal Data through Ontology-based Representation:A Case Study with Brazilian Judicial Appeals

In Brazil, legal requirements for public information access, as mandated by Law no 12.527/2011, have amplified the role of the open data portals in disseminating data of collective and general interest. Despite legal provisions, there are persistent difficulties in presenting data in first-class semantic formats, which ultimately creates obstacles for digital citizens to fully exercise their newfound rights to information access. These obstacles can be addressed by building semantic data warehouses to enhance the use of open data through computational ontologies. In this paper, we demonstrate the use of a well-founded legal ontology for representing data from legal decisions extracted from a Brazilian judicial organ website. We focused our approach on a specific type of appeal in the Brazilian legal system, the Request for Standardization (RS) of interpretation of federal law, which seeks to standardize the understanding of the Appeals Panels of Federal Special Courts. Employing web scraping techniques, we built a complete ETL (Extract, Transform, Load) process to triplify data on RS appeals and their rulings. We used a gUFO-based OWL renderization of a previously developed OntoUML ontology (called OntoRS) to transform the extracted data into a suitable RDF format and populate a Virtuoso triple store. Thus, the OntoRS ontology allowed us to perform SPARQL queries to obtain new insights, metrics and small RDF graphs.</p

Les submersions de tempête de la nuit du 10 au 11 mars 2008 sur la côte d’Albâtre (Haute-Normandie, France) : détermination météo-marine

 Plus que l’analyse de l’impact morpho-sédimentaire sur les plages de galets haut-normandes de la tempête du 10 au 10 mars 2008, l’objet de cet article est de présenter les caractéristiques météo-marines en cause et leurs interactions éventuelles dans le processus des submersions qui ont affecté la côte d’Albâtre. Quelques éléments d’information qualitative concernant l’ajustement morpho-sédimentaire spécifique des plages de galets anthropisées à ce type de forçage seront fournis. En effet, la tempête du 10 au 11 mars n’a pas fait l’objet de mesures morpho-sédimentaires spécifiques, mais visuellement, correspond en tout point à ce qui a pu être mesuré sur les plages haut-normandes lors de campagnes récentes réalisées avant et après tempête. L’étude se concentre sur le secteur de Dieppe, qui bénéficie d’un marégraphe (implanté dans l’avant-port de Dieppe) et d’un poste de mesures météorologiques situé au sémaphore de la Marine nationale, sous maintenance de Météo-France, et permettant notamment l’analyse de « données minute ». Cette étude révèle que les facteurs d’ordre purement météorologique qui ont abouti aux submersions de la nuit du 10 au 11 mars n’étaient pas de nature extrême, et que c’est la complexité des interactions en cause (conditions météorologiques de surface et d’altitude, morpho-sédimentaires et surtout marégraphiques et houlographiques), qui permet de comprendre l’ampleur de certaines inondations. Un « forçage » météorologique plus violent sur ces interactions, tel que celui observé le 17 décembre 2004, qui eut peu de conséquence en raison d’un faible coefficient de marée (71), pourrait aboutir à des submersions beaucoup plus sévères sur des sites urbanisés dont l’altitude et est parfois égale, voire inférieure à celle des pleines mers de vive eau.More than the analysis of the morpho-sedimentary impact on Haute-Normandie gravel beaches during the storm of March 10th-11st 2008, the aim of this paper is to present meteorological and marine characteristics and their possible interactions in the process of storm surges which affected the « côte d’Albâtre ». Some elements of qualitative information concerning the specific morpho-sedimentary adjustment of these anthropized gravel beaches face to this meteorological forcing will be provided. Indeed, the storm of March 10th-11st 2008 was not subjected to specific morpho-sedimentary measurements but visually fits with the measurements taken on Haute-Normandie beaches during recent surveys executed before and after storm. This study focuses on the Dieppe area, which has a tide gauge (located in the outer port of Dieppe) and a meteorological measurement post, located at the national Navy semaphore, under the servicing of Meteo-France, and allowing analysis of « minute-data ». This study reveals that meteorological factors, ending in storm surges during the night of March 10th-11st, were not of extreme nature, and that it is the complexity of interactions (surface and altitude meteorological conditions, morpho-sedimentary and especially tidal and wave conditions) that allows an understanding of the extent of several floodings. A more violent meteorological « forcing » on these interactions, such as during December 17th 2004, that had few consequences because of low tidal coefficient (71), would end in much more important storm surges

Electrochemical Impedance Analysis of Symmetrical Ni/Gadolinium-Doped Ceria (CGO10) Electrodes in Electrolyte-Supported Solid Oxide Cells

One of the most powerful tools in solid oxide cell (SOC) characterization is electrochemical impedance spectroscopy, which can unfold important insights into SOC performance characteristics and degradation behavior. To obtain a better understanding of the electrochemical behavior of Ni/CGO fuel electrodes, this work presents a comprehensive investigation of state-of-the-art Ni/CGO10- based electrolyte-supported cells. Commercial Ni/CGO10|CGO10|3YSZ|CGO10|Ni/CGO10 symmetrical cells were characterized between 550–975°C at pH2 = 0.8 bar and pH2O = 0.2 bar, and for different H2/H2O gas mixtures at 550°C. (i) Small electrode area, (ii) thin electrodes and (iii) large gas flow rates were used to minimize mass transport contributions. Based on distribution of relaxation times (DRT) analysis an equivalent circuit model was derived. Electrode process contributions on Ni/CGO were determined by means of a complex non-linear least square fit of the equivalent circuit model to the experimental data. One low frequency process at 0.1–1 Hz and one middle frequency process at 10–100 Hz were identified and correlated to a surface and a bulk process, respectively. Values for the apparent activation energy barriers and reaction orders with respect to steam and hydrogen content were determine

Performance and Limitations of Nickel-Doped Chromite Anodes in Electrolyte-Supported Solid Oxide Fuel Cells

Ni-doped chromite anodes were integrated into electrolyte-supported cells (ESC) with 5x5 cm2 size and investigated in fuel cell mode with H2/H2O fuel gas. Both a stoichiometric and a nominally A-site deficient chromite anode material showed promising performance at 860 °C approaching the ones of state-of-the-art Ni/Gd-doped ceria (CGO) anodes. While the difference in polarization resistance was small, an increased ohmic resistance of the perovskite anodes was observed, which is related to limited electronic conductivity of the perovskites. Increasing the chromite electrode thickness was shown to enhance performance and stability considerably. Degradation increased with current density, suggesting its dependency on the electrode potential, and could be reversed by redox cycling. Sulfur poisoning with 20 ppm hydrogen sulfide led to rapid voltage drops for the chromite anodes. It is discussed that Ni nanoparticle exsolution facilitates hydrogen dissociation to the extent that it is not rate-limiting at the investigated temperature unless an insufficiently thick electrode thickness is employed or sulfur impurities are present in the feed gas

Hydrogen and syngas production by solid oxide electrolysis with solar heat integration

Solid oxide electrolysis is especially attractive in terms of efficiency if coupled with a high temperature heat source. The external thermal energy can be used to evaporate the supplied process water and to heat up the steam and/or the carbon dioxide to the required electrolysis temperature. The external heat is ideally generated by renewable and environmental-friendly sources, such as solar radiation. The main challenges in this approach is the coupling between an intermittent heat source and the solid oxide electrolyser stack and its operation with environmental varying conditions while enabling high efficiency and low degradation. Here we report the recent results of the project Future Fuels 2 at the German Aerospace Center (DLR). The aim is to investigate the production of green hydrogen and syngas by means of solar heat integrated solid oxide electrolysis. In this project a test platform for syngas production was developed at DLR, consisting of a solar thermal steam generator and 12-cells stack, which was supplied by SOLIDpower S.p.A (Mezzolombardo, Italy). The solar heat was supplied by a high flux solar simulator based on elliptical reflectors with 10 xenon short-arc lamps. The test platform optimizations, e.g. reduction of the heat losses, minimization of steam instabilities and increase of the steam temperature, are outlined. Results on the stack behavior in steam and co-electrolysis are presented and discussed. The stack was operated for 200 h in co-electrolysis mode under intermittent supply of steam, and CO2, powered with solar heat and of electrical power, respectively. These varying operating conditions simulate fluctuations of the renewable energies, e.g. high solar radiation, clouds formation and day-night cycle. Both, in steam- and in co-electrolysis the SOEC stack showed a very good and homogeneous behavior at 750°C and 90 % gas conversion. In order to convert 90 % of the supplied process gases, which corresponds to 7.5 slpm of produced H2 or CO+H2 syngas, an electrolysis power of ca. -1.5 kW was necessary. High electrical efficiencies of 89% (steam electrolysis) and 93 % (co-electrolysis) were achieved. The stack behaviour in both electrolysis modes was almost identical. During the intermittent operation altogether 14 000 liters of syngas (H2+CO) were produced successfully. Moreover, the stack degradation was very low