▁of ▁Bash k ort ost an , ▁Russia : ▁Ab zak ovo , ▁Bay m ak sky ▁District , ▁Republic ▁of ▁Bash k ort ost an , ▁a ▁village ▁in ▁Bay m ak sky ▁District ▁Ab zak ovo , ▁Bel oret sky ▁District , ▁Republic ▁of ▁Bash k ort ost an , ▁a ▁sel o ▁in ▁Bel oret sky ▁District , ▁and ▁the ▁ski ▁resort ▁of ▁the ▁same ▁name ▁located ▁there ▁Ab zak ovo , ▁U ch alin sky ▁District , ▁Republic ▁of ▁Bash k ort ost an , ▁a ▁village ▁in ▁U ch alin sky ▁District <0x0A> </s> ▁U sed ▁primarily ▁in ▁av iation , ▁self - se aling ▁is ▁a ▁technology — in ▁wide ▁use ▁since ▁World ▁War ▁II — that ▁prevents ▁aircraft ▁fuel ▁t anks ▁or ▁bl add ers ▁from ▁le aking ▁fuel ▁and ▁ign iting ▁after ▁being ▁dam aged ▁by ▁enemy ▁fire . ▁ ▁Typ ical ▁self - se aling ▁t anks ▁have ▁multiple ▁layers ▁of ▁rub ber ▁and ▁rein for cing ▁fabric , ▁one ▁of ▁vul can ized ▁rub ber , ▁and ▁one ▁of ▁un tre ated ▁natural ▁rub ber , ▁which ▁can ▁abs orb ▁fuel , ▁sw ell , ▁and ▁expand ▁when ▁it ▁comes ▁into ▁contact ▁with ▁the ▁fuel . ▁When ▁a ▁fuel ▁tank ▁is ▁pun ct ured , ▁the ▁fuel ▁see ps ▁into ▁the ▁layers , ▁causing ▁the ▁un tre ated ▁layer ▁to ▁sw ell ▁and ▁thus ▁se al ▁the ▁pun ct ure . ▁ ▁A ▁similar ▁concept ▁is ▁also ▁employed ▁for ▁making ▁self - se