Well just as a sample: http://www.elsevier.com/connect/trade-sanctions-against-iran-affect-publishers . Of course as far as I know the sanctions has been modified (or clarified) in recent years to exclude academic only affiliations (it was not so for example in 2004). And of course offering post-doc or other kinds of affiliations is not considered as a problem as this would change the affiliation (but not in many fields which were considered sensitive somehow).
Sahand university is a mid-ranking university as far as I know. But about Azad (and also Payam-noor) , one should note that they are huge non-homogenous academic bodies. Azad has more than 1.5 million students and 100 branches! one can imagine that at least some of its institutes or branches have some degree of quality.
And as a general rule, results from any one should be verified, and should be verified more closely when the authors or the research group do not show previous credits.
