The Foundation is authorized to cooperate in any international scientific or engineering activities consistent with the purposes of this chapter and to expend for such international scientific or engineering activities such sums within the limit of appropriated funds as the Foundation may deem desirable. The Director may defray the expenses of representatives of Government agencies and other organizations and of individual scientists or engineers to accredited international scientific or engineering congresses and meetings whenever he deem 1 it necessary in the promotion of the objectives of this chapter. In this connection, with the approval of the Secretary of State, the Foundation may undertake programs granting fellowships to, or making other similar arrangements with, foreign nationals for study and research in the sciences or in engineering in the United States without regard to section 1869 of this title or the affidavit of allegiance to the United States required by section 1874(d)(2) 2 of this title.