Degradation 1 Degradation index Degradation indexes 1 Degradation model 1 Durability 1 Dynamic condition 1 Dynamic conditions 1 Dynamics 1 Electrochemical degradation 1 Electrochemical degradation model 1 Failure (mechanical) 1 Failure range 1 Forecasting 1 Gas fuel purification 1 Operating condition 1 Prognostic modeling 1 Proton exchange membrane fuel cells 1 Proton exchange membrane fuel cells (PEMFC) 1 Proton-exchange membranes fuel cells 1 Remaining useful life 1 Remaining useful lives 1 Systems engineering 1