but is also responsible for stratospheric ozone depletion and climate change due to the production of nitrous oxide (N 2 O) during the microbial transformation of N via nitrification and denitrification (Seitzinger & Phillips, 2017;Tian et al., 2020). N removal processes, including denitrification and anaerobic ammonium oxidation (anammox), which convert dissolved inorganic nitrogen (DIN) to di-nitrogen (N 2 ), are considered to be globally significant pathways for reactive N removal in aquatic ecosystems (Birgand et al., 2007;. Processes controlling N removal
The metro door system is one of the high failure rate subsystems of metro trains. The Failure Mode, Effects and Criticality Analysis (FMECA) method is applied to analyze the reliability of metro door system in this paper. Firstly, failure components of the door are statistically analyzed, and the major failure components are determined. Secondly, failures are classified according to their impacts on operation, and methods of calculating failure mode criticality and the related coefficients are illustrated. Finally, the FMECA is detailed in the selected 12 failure modes, and the failure modes are discovered that they have the most significant effect on metro door system. The obtained results can be used for optimal design and maintenance of the metro door system.
In order to meet the requirements of corrosion resistance of the grounding material and thermal stability of the grounding material of the transmission line towers, under the condition of power frequency current and high-frequency lightning current scattering into the ground in the case of short-circuit fault and lightning strikes, a kind of high-current capability flexible graphite grounding material was developed. The corrosion resistance of the flexible graphite grounding material and the steel type grounding material was compared by the soil simulation solution corrosion tests. The contact performance with different soils of the two materials was analyzed by the actual contact resistance measurement test. The thermal stability and the impulse current effective length of this grounding material were studied by means of simulation calculation. The results show that the high-current capability flexible graphite grounding material has a strong anticorrosion characteristic, whose reliable service life can exceed 30 years. Compared to the round steel grounding material, the contact resistance with the soil can be reduced by approximately 30%, and the impulse current effective length can be increased by about 30%. INDEX TERMS Flexible graphite grounding material, corrosion resistant characteristic, contact resistance, thermal stability, impulse current effective length.
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