Long-term (4 year) degradation behavior of coated stainless steel 441 used for solid oxide fuel cell interconnect applications

The present work aims to investigate the long-term stability of Ce/Co coated AISI 441 used as an interconnect material in solid oxide fuel cells (SOFC). Being a commercially available alloy the use of AISI 441 would greatly reduce the cost of SOFCs in comparison to tailor-made interconnect materials such as Crofer 22 APU. To analyze the long-term stability Ce/Co coated AISI 441 is exposed in air at 800 \ub0C for up to 38 000 h. Mass gain values are recorded continuously. After 7 000, 23 000, and 35 000 h area specific resistance (ASR) measurements are performed, and cross-sections are prepared and analyzed using scanning electron microscopy (SEM) and energy dispersive x-ray (EDX) spectroscopy. Cr-evaporation measurements are conducted on samples exposed for up to 38 000 h

Importancia del espacio público en el desarrollo de actividades sociales en el distrito de Laredo 2022

La Finalidad del presente estudio mantiene como objetivo de estudio que es determinar la importancia del espacio público para el desarrollo de actividades sociales en el distrito de Laredo. El diseño aplicado en esta investigación es no experimental transversal, con un carácter correlacional, ya que incluye un estudio que establece una interacción entre las variables y el alcance de la relación entre ellas, siendo la existencia de las actividades que realizan la población de manera libre, como parte de su cultura, para contribuir a la formación de la identidad social, llevando a cabo estas actividades en los espacios públicos del distrito. Se realizo fichas de observaciones y un cuestionario que permitió la recolección de datos mediante programas de office y AutoCAD 2020, cuyos resultados fueron muy importantes para ambas variables, a su ves toda información fue analizada a través de cuadros, gráficos, tablas y diagramas. Por ello se concluyó que los espacios públicos que abarcan actividades sociales, son importantes para que una población conozca sobre su cultura y mantenga una relación directa con su pasado, que garantice un adecuado desarrollo social y conserve su identidad, para la nueva generación

Novel mixed conducting oxides for sold oxide fuel cells (SOFC's) applications

This thesis describes the search for new mixed conductors as potential anodes and cathodes for applications in Solid Oxide Fuel Cells. Several compounds have been synthesised and characterised by means of different diffraction techniques (X-Rays, neutrons and electrons), high resolution electron microscopy and electrical measurements (AC Impedance Spectroscopy and DC resistivity measurements).EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Novel mixed conducting oxides for sold oxide fuel cells (SOFC's) applications

This thesis describes the search for new mixed conductors as potential anodes and cathodes for applications in Solid Oxide Fuel Cells. Several compounds have been synthesised and characterised by means of different diffraction techniques (X-Rays, neutrons and electrons), high resolution electron microscopy and electrical measurements (AC Impedance Spectroscopy and DC resistivity measurements).EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Microstructural and compositional optimization of La0.5Ba0.5CoO3−δ—BaZr1−zYzO3−δ (z=0, 0.05 and 0.1) nanocomposite cathodes for protonic ceramic fuel cells

Cathodes are one of the key components of protonic ceramic fuel cells (PCFCs) requiring further development to enhance the performance of PCFCs. This encompasses the optimization of material compositions and microstructures, as well as a further understanding of the electrode processes. Here, a compositional optimization of a La0.5Ba0.5CoO3−δ—BaZrO3-based nano-composite cathode prepared by exsolution of a single-phase material was performed by substituting 5 and 10 mol% Y at the B-site in the BaZrO3 phase. Electrodes with different microstructures were prepared by two different deposition methods, spray coating and screen printing, and by varying the firing temperature from 600°Cto 1100 °C. Further, composite electrodes were prepared by directly coating and firing the single-phase materials on the dense electrolyte to prepare symmetric cells. A good adhesion of the cathode to the electrolyte was observed in all cases. In general, a more homogeneous microstructure was observed for the cathodes prepared by screen printing. The single step method encompassing exsolution of the single phase and firing of the symmetric cells yielded significant improvement in the cathode performance compared to the other routes. The best electrochemical performance was observed for La0.5Ba0.5CoO3−δ—BaZr0.9Y0.1O2.95 cathode with an area specific resistance of 4.02 Ω·cm2 at 400 °Cand 0.21 Ω·cm2 at 600 °Cin 3%moist synthetic air. These results are among the best reported for cathodes of PCFCs as will be discussed.publishedVersio