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Renewed interest in Arctic oil and gas has meant a renewed need for skills tin constructing the pipelines that will carry these resources to market. But pipeline professionals may find [...]

Solid oxide fuel cells (SOFCs) are highly efficient devices for energy conversion. However, their performance is hindered by the poisoning of their oxygen electrode materials by chromium and sulfur species. While previous studies have proposed a nucleation theory of Cr and S poisoning as a mechanism, little is known about the adsorption behaviors and compound formation steps during the poisoning process. This knowledge is critical for understanding the poisoning mechanisms and developing effective mitigation strategies. In this study, the state-of-the-art SOFC oxygen electrode material, La0.6Sr0.4Co0.2Fe0.8O3(LSCF), is used as a modeling system. A realistic surface structure will be constructed by grand canonical Monte Carlo (GCMC) simulation. Then, the adsorption energies as a function of surface chemistry will be calculated using density functional theory (DFT). The results revealed the importance of surface chemistry in determining the energetics and kinetics of precursor adsorption and compound formation.

State-of-the-art solid oxide fuel cell (SOFC) oxygen electrode materials such as La0.6Sr0.4Co0.2Fe0.8O3-δ(LSCF) continue to be plagued by degradation primarily through strontium (Sr) segregation to the electrode surface and subsequent passivating poisoning reactions with chromium- and sulfur-containing species. Surface infiltration of more oxidizable cations is of interest for LSCF electrodes in order to reduce the electrostatic driver of Sr segregation and due its reported success in reducing Sr segregation and electrochemical degradation on LSC electrodes. In this work, we investigate the thermal stability of Hf, Nd, and Pr infiltrated cations at porous LSCF electrode surfaces. These select cations are of interest as surface infiltrates due to their more oxidizable nature. We demonstrate that infiltrated Hf, Nd, and Pr cations are not thermally stable at the LSCF electrode surface at standard SOFC operating temperatures, diffusing substantially away from the surface above 800°C.

The purpose of this research was the validation of an offset deformable barrier (ODB) model using component and sled testing and simulations of both. The material parameters developed in component punch tests and their simulations work well for the ODB model. The finite model developed in this report results in good correlation between sled tests and simulations and this ODB model can now be used in vehicle simulations. This will allow the various ODB tests to be better modelled with better predictions of vehicle response. Thus, crashworthiness engineers may be able to design better for the ODB test. An additional finding of interest was that the honeycomb material in an ODB is somewhat unstable, because its strength is approximately two orders of magnitude greater in the primary loading direction than in the other two directions.

Put files on a reduction plan while you're at it I failed to write in praise of Don Crabb's commentary (MacWEEK, Jan. 8), but I certainly support his ideas on […]