▁caused ▁by ▁rub ber ▁O - r ings ▁that ▁were ▁being ▁used ▁well ▁below ▁their ▁glass ▁transition ▁temperature ▁on ▁an ▁unus ually ▁cold ▁Florida ▁morning , ▁and ▁thus ▁could ▁not ▁flex ▁ade qu ately ▁to ▁form ▁proper ▁se als ▁between ▁sections ▁of ▁the ▁two ▁solid - f uel ▁ro cket ▁boost ers . ▁ ▁Bi opol ym ers ▁ ▁Sol - gel ▁▁ ▁With ▁the ▁vis cos ity ▁of ▁a ▁sol ▁adjust ed ▁into ▁a ▁proper ▁range , ▁both ▁optical ▁quality ▁glass ▁fi ber ▁and ▁ref ract ory ▁cer am ic ▁fi ber ▁can ▁be ▁drawn ▁which ▁are ▁used ▁for ▁fi ber ▁opt ic ▁sens ors ▁and ▁thermal ▁ins ulation , ▁respectively . ▁The ▁mechan isms ▁of ▁hydro ly s is ▁and ▁cond ens ation , ▁and ▁the ▁r he ological ▁factors ▁that ▁bias ▁the ▁structure ▁toward ▁linear ▁or ▁branch ed ▁structures ▁are ▁the ▁most ▁critical ▁issues ▁of ▁sol - gel ▁science ▁and ▁technology . ▁ ▁Ge oph ys ics ▁ ▁The ▁scientific ▁discipline ▁of ▁ge oph ys ics ▁includes ▁study ▁of ▁the ▁flow ▁of ▁mol ten ▁la va ▁and ▁study ▁of ▁de br is ▁flows ▁( fl uid ▁mud sl ides ). ▁This ▁discipl inary ▁branch ▁also ▁de als ▁with ▁solid ▁Earth ▁materials ▁which ▁only ▁exhib it ▁flow ▁over ▁extended ▁time - scal es . ▁Those ▁that ▁display ▁vis c ous ▁behaviour ▁are ▁known ▁as ▁r he ids . ▁For ▁example , ▁gran ite ▁can ▁flow ▁pl ast ically ▁with ▁a ▁neg lig ible ▁yield ▁stress ▁at ▁room ▁temper atures ▁( i