MATERIAL_MIXTURE
 

I'm working with fluent 6.0 and, by reading UDF manual, I've found these macros only in the example of 4.5.10:

THREAD_MATERIAL(t,0); MATERIAL_TYPE(m); MATERIAL_PROP(sp,PROP_mwi).

Which is the meaning of the index 0 in the first??? In which case is it advisable to use them?(without DPM MACROS!!!)

Thanks in advance!

Ari