Application of the residue number system to the matrix multiplication problem

Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to [email protected], referencing the URI of the item.Includes bibliographical references.Not availabl

Microstructural Analysis of a metal-supported SOFC after redox-cycling

A metal-supported SOFC (MSC) has been developed with the aim of an application in an auxiliary power unit (APU) for mobile systems. This cell design is expected to be more robust towards thermo-, mechanical- and chemical stresses that arise during operation of the SOFC-system when compared to the state-of-the-art anode supported cells (ASC). One of the most important cell-degradation pathways is the (partial) oxidation of the anode, due to oxygen diffusion into the fuel side of the stack during system shutdown. The oxidation of the nickel catalyst leads to an expansion of the anode and strain is induced within the cell, which results in microstructural degradation if a critical degree of oxidation is exceeded. We exposed MSC-halfcells to cyclic oxidation conditions by introducing air to the fuel side electrode followed by subsequent reduction in Ar/H2(4%). A detailed microstructural analysis of these samples is presented. Due to the novel MSC-concept, a higher critical degree of oxidation of nickel is tolerated before irreversible damage and cell failure are observed

Advances beyond traditional SOFC cell designs

Research and development of Solid Oxide Fuel Cell (SOFC) technology has been carried out at the Jülich research center for more than 20 years. A standard cell design based on a porous nickel cermet has been established and tested with stationary conditions, for which a power density of 1.25 W/cm2 at 800°C in H2 was obtained. In order to broaden the field of possible applications, new cell designs have been developed. Among those are metal-supported SOFCs (MSC), which promise increased robustness against thermal-, mechanical and chemical stresses, as well as cheaper production costs. While the MSC development may find an application in mobile devices another cell design concept aims at much lower operating temperatures. For this cell type a very thin zirconia membrane is deposited on top of a standard anode support via a multi-step sol/gel-route. With this setup a reduction of the operating temperature to 600°C with a power output of 1.25 W/cm2 could be demonstrated