(a) Describe the main stages of a sol-gel method to produce oxide ceramic powders and explain TWO advantages of this method. (b) Discuss how alumina powder can be processed into an alumina tube and a crucible via forming and sintering. (c) Discuss why controlling porosity and grain size during sintering is important for enhancing the mechanical strength of sintered ceramics. (d) Outline the processes required to produce long SiC fibres. Name THREE useful properties associated with these fibres