Nondestructive neutron activation analysis was performed on the nickel purified by floating zone-refining and anion exchange. It is found that floating zone-refining in vacuum is effective to remove Na, Sc, Cr, Zn, As, Ag, Sb and Hg through vaporization in addition to elimination of Se, Sb, Ta, Sm and Tb through segregation. Anion exchange method is also effective to separate Fe, Co, Zn, Mo, Hg...

in this paper the issue of evaluating iranian oil refineries performance has been discussed. the research is based on math modelling by operational research techniques. to do so, of the proposed scenarios and different math programming models, a model is made by combining dea with goal programming techniques that compared with the old classical dea models which measures the efficiency and produ...

Our purpose is to formalize two potential refinements of single-sorted algebraic data types – subalgebras and algebras which satisfy equivalence relations – by considering their categorical interpretation. We review the usual categorical formalization of singleand multi-sorted algebraic data types as initial algebras, and the correspondence between algebraic data types and endofunctors. We intr...