▁▁ ▁Category : Pop ulated ▁places ▁in ▁Dou ma ▁District <0x0A> </s> ▁Phot ome chan ical ▁effect ▁is ▁the ▁change ▁in ▁the ▁shape ▁of ▁a ▁material ▁when ▁it ▁is ▁exposed ▁to ▁light . ▁This ▁effect ▁was ▁first ▁documented ▁by ▁Alexander ▁Graham ▁Bell ▁in ▁ 1 8 8 0 . ▁More ▁recently , ▁Ken ji ▁U ch ino ▁demonstrated ▁that ▁a ▁phot ost rict ive ▁material ▁could ▁be ▁used ▁for ▁legs ▁in ▁the ▁construction ▁of ▁a ▁mini ature ▁opt ically - power ed ▁" walk er ". ▁ ▁The ▁most ▁common ▁mechanism ▁of ▁phot ome chan ical ▁effect ▁is ▁light - indu ced ▁he ating . ▁ ▁Phot ome chan ical ▁materials ▁may ▁be ▁considered ▁smart ▁materials ▁due ▁to ▁their ▁natural ▁change ▁implemented ▁by ▁external ▁factors . ▁ ▁References ▁ ▁See ▁also ▁▁ ▁Sm art ▁materials ▁ ▁External ▁links ▁▁ ▁The ▁Non linear ▁Opt ics ▁Web ▁Site ▁ ▁Category : Me chan ics ▁Category : Material s ▁science <0x0A> </s> ▁The ▁following ▁lists ▁events ▁that ▁will ▁happen ▁during ▁ 2 0 1 5 ▁in ▁Slov ak ia . ▁ ▁Inc umb ents ▁ ▁Head ▁of ▁State ▁▁ 2 0 1 5 ▁is ▁the ▁first ▁full ▁year ▁of ▁the ▁ 4 th ▁President ▁Andre j ▁K iska , ▁elected ▁as ▁an ▁independent ▁candidate ▁in ▁the ▁ 2 0 1 4 . ▁▁ ▁President ▁– ▁Andre j ▁K iska ▁( Ind ep endent ) ▁ ▁Government ▁▁ 2 0 1 5 ▁is ▁the ▁last ▁full ▁year ▁of ▁the ▁ 8 th ▁National ▁Council . ▁Next ▁parliament