ra ▁al umn i ▁Category : L iving ▁people ▁Category : Date ▁of ▁birth ▁missing ▁( l iving ▁people ) ▁Category : Am b ass adors ▁of ▁Australia ▁to ▁I cel and ▁Category : Am b ass adors ▁of ▁Australia ▁to ▁Norway ▁Category : Austral ian ▁women ▁amb ass adors <0x0A> </s> ▁In ▁therm od ynam ics , ▁a ▁therm ally ▁isolated ▁system ▁can ▁exchange ▁no ▁mass ▁or ▁heat ▁energy ▁with ▁its ▁environment . ▁The ▁internal ▁energy ▁of ▁a ▁therm ally ▁isolated ▁system ▁may ▁therefore ▁change ▁due ▁to ▁the ▁exchange ▁of ▁work ▁energy . ▁The ▁entropy ▁of ▁a ▁therm ally ▁isolated ▁system ▁will ▁increase ▁in ▁time ▁if ▁it ▁is ▁not ▁at ▁equilibrium , ▁but ▁as ▁long ▁as ▁it ▁is ▁at ▁equilibrium , ▁its ▁entropy ▁will ▁be ▁at ▁a ▁maximum ▁and ▁constant ▁value ▁and ▁will ▁not ▁change , ▁no ▁matter ▁how ▁much ▁work ▁energy ▁the ▁system ▁ex changes ▁with ▁its ▁environment . ▁To ▁maintain ▁this ▁constant ▁entropy , ▁any ▁exchange ▁of ▁work ▁energy ▁with ▁the ▁environment ▁must ▁therefore ▁be ▁qu as ist atic ▁in ▁nature , ▁in ▁order ▁to ▁ass ure ▁that ▁the ▁system ▁remains ▁essentially ▁at ▁equilibrium ▁during ▁the ▁process . ▁ ▁The ▁opposite ▁of ▁a ▁therm ally ▁isolated ▁system ▁is ▁a ▁therm ally ▁open ▁system , ▁which ▁allows ▁the ▁transfer ▁of ▁heat ▁energy ▁and ▁entropy . ▁Th erm ally ▁open ▁systems ▁may ▁vary , ▁however , ▁in ▁the ▁rate ▁at ▁which ▁they ▁equ il ibr ate , ▁depending ▁on ▁the ▁nature ▁of ▁the ▁boundary ▁of ▁the ▁open ▁system . ▁At ▁equilibrium ,