A lead acid separator should:

A lithium air separator should:

A lithium-sulfur separator should:

A piece of aluminium undergoes a tensile test resulting in the following force vs extension plot:

Assume a width of 13.1 mm and a thickness of 5.2 mm for the piece of aluminium

Answer in MPa to 1 decimal place

You MUST upload your workings for this question.

The following plot shows the effect of temperature on the modulus of two polymers, "X" and "Y". 

Answer the following questions in the space below:

a) What type (or class) of polymers are "X" and "Y". Explain your answer.

b) Give a specific example for each type of polymer.

c) If the service temperature of a component is between 50 °C and 120 °C, which polymer is more suitable? Explain your answer. 

d) Explain the importance of the rubbery regions for both "X" and "Y" and relate this to the type of bonding present in the polymers.

Using your lecture notes, 

i) List the thermal transitions of HDPE.  

ii) What happens to the polymer chains at these thermal transitions?

iii) Are these transitions reversible? Explain why.

iv) Explain how these transitions can be used to estimate the service temperature of HDPE.

A metal alloy has the following stress-strain curve up to the point of fracture as shown by the arrow.

Stress (fracture) = 960 MPa

Strain (fracture) = 0.12

Calculate mathematically, the ductility of the metal alloy. Your answer must be expressed at % strain (no units) to 3 significant figures

Hint: Use the gridlines to help you calculate the stress and strain values.

YOU MUST UPLOAD YOUR CALCULATIONS FOR THIS QUESTION

How many atoms fall outside the unit cell shown below?

The

elastic modulus of a material is most closely correlated with which of the

following physical properties?

The following plot shows the change in the modulus of elasticity (Young's modulus) with temperature for two polymers A and B

Which of the following is consistent when considering this plot.