Abstract: A system and method for reducing concentrations of reactants in gases flowing through an exhaust system are disclosed. Briefly described, one embodiment comprises creating a turbulent flow of gases along a periphery region of an exhaust pipe, the turbulent flow created by the gases transported over a wire mesh residing in the periphery region; and mixing the gases in the periphery region with a reactant gas being transported in a flow-through region, the mixing caused by the turbulent flow of gases, such that concentration of the reactant gas is reduced as the reactant gas is transported through the exhaust system.

Abstract: A fuel cell system is disclosed comprising a housing having an interior space fluidly containing a fuel cell stack and a flame arresting recombiner, wherein: (1) the flame arresting recombiner comprises at least one fuel cell having at least one anode supply channel fluidly connecting the fuel cell and the interior space of the housing; and (2) the anode supply channel of the fuel cell of the flame arresting recombiner is configured to prevent flame propagation.

Abstract: An electrochemical fuel cell stack comprises a plurality of fuel cell assemblies, wherein, each fuel cell assembly comprises a cell compressed between a pair of flow field plates, a perimeter seal circumscribing the cell and interposed between the pair of flow field plates, and a first diode, having an aspect ratio greater than 10:1, positioned adjacent to, and outside of, the perimeter seal along a first edge of the cell and interposed between the pair of flow field plates.