Q$1)$

$($a$)$ To harden an austenitic steel material, someone suggests heat treatment. Explain if you agree with this approach. If you disagree, propose an altemative method. Justify your answers.

$[3]$

$($b$)$ A surgeon needs degradable materials to fill a small gap in a patient's broken leg. Propose a material and explain why you select it$.$ Explain how it is degraded in the body.

$($c$)$ A polyethylene specimen is made of the following fractional distribution.

$\backslash$table$[[Ni,0\mathrm{.}1,0\mathrm{.}2,0\mathrm{.}3,0\mathrm{.}3,0\mathrm{.}1],[Mi(k\frac{g}{m}ol),10,20,30,40,50]]$

Where $Ni$ is number of moles of i and $Mi$ is molecular weight of $i.$

$($i$)$ Calculate Mw and Mn$.$

$4$

$($ii$)$ Would the polymer become crystalline, noncrystalline, or semicrystalline when cooled from melt?

$[2]$

$($iii$)$ Suggest a method to enhance the Young's modulus of this polymer for its application as orthodontic braces. Justify your answer.

$[2]$

$($d$)$ Describe the rationale behind the use of composite biomaterials. Give an example of application where a composite biomaterial is used. Explain the role of each component.

$5$