Are there any macros for mole fraction? i just find C_YI(c,t) for mass fraction...

Not a Macro, but there there is a function..

Material *m=THREAD_MATERIAL(t); Mole_Fraction(m,yi,xi);

where yi is the input array of mass fractions and xi is the output array of mole fractions

thanks for reply, but how can i get the proper material pointer when there's more than one material in a thread. for instance, species transport in a porus zone, this zone include both mixture and solid materials. -kevin