Tafsir of At-Tur 52:13

(That is, they are pushed with violent and severe force, in that their hands are chained to their necks and their forelocks are gathered to their feet, then they are thrust into the Fire and cast into it. Zayd ibn Ali, al-Sulami, and Abu Raja’ recited "yud‘awna" with a quiescent dal and a fatha on the ‘ayn, derived from al-du‘a (calling), in which case "da‘an" serves as a circumstantial qualifier (hal); meaning they are summoned to it, being called. The word "Yawm" (The Day) is either an appositive to the day of [the heaven's] "undulating" (tamuru), or it acts as an adverbial modifier for a statement implied by His Almighty’s saying...)