ar ▁and ▁extension . ▁ ▁App lications ▁▁ ▁R he ology ▁has ▁applications ▁in ▁materials ▁science , ▁engineering , ▁ge oph ys ics , ▁phys i ology , ▁human ▁bi ology ▁and ▁ph arma ce ut ics . ▁Material s ▁science ▁is ▁util ized ▁in ▁the ▁production ▁of ▁many ▁industri ally ▁important ▁subst ances , ▁such ▁as ▁c ement , ▁paint , ▁and ▁ch oc olate , ▁which ▁have ▁complex ▁flow ▁characteristics . ▁In ▁addition , ▁pl astic ity ▁theory ▁has ▁been ▁similarly ▁important ▁for ▁the ▁design ▁of ▁metal ▁forming ▁processes . ▁The ▁science ▁of ▁r he ology ▁and ▁the ▁character ization ▁of ▁vis co el astic ▁properties ▁in ▁the ▁production ▁and ▁use ▁of ▁polym er ic ▁materials ▁has ▁been ▁critical ▁for ▁the ▁production ▁of ▁many ▁products ▁for ▁use ▁in ▁both ▁the ▁industrial ▁and ▁military ▁se ctors . ▁Study ▁of ▁flow ▁properties ▁of ▁liqu ids ▁is ▁important ▁for ▁ph arm ac ists ▁working ▁in ▁the ▁manufact ure ▁of ▁several ▁dos age ▁forms , ▁such ▁as ▁simple ▁liqu ids , ▁o int ments , ▁cre ams , ▁past es ▁etc . ▁The ▁flow ▁behavior ▁of ▁liqu ids ▁under ▁applied ▁stress ▁is ▁of ▁great ▁relev ance ▁in ▁the ▁field ▁of ▁ph arm acy . ▁Flow ▁properties ▁are ▁used ▁as ▁important ▁quality ▁control ▁tools ▁to ▁maintain ▁the ▁superior ity ▁of ▁the ▁product ▁and ▁reduce ▁batch ▁to ▁batch ▁variations . ▁ ▁Material s ▁science ▁ ▁Pol ym ers ▁▁ ▁Ex amples ▁may ▁be ▁given ▁to ▁illustrate ▁the ▁potential ▁applications ▁of ▁these ▁principles ▁to ▁practical ▁problems ▁in ▁the