R_FeOH2_expr k_FeOH2*(cFe*(tcd.cOH)^2-Keq_FeOH2) "FeOH2 formation rate"
R_FeOH2 if(R_FeOH2_expr>0,R_FeOH2_expr,0) "FeOH2 formation rate, irreversible"
epsl if(z>0,1,epsl_pit) "Electrolyte volume fraction"