Question $3.$

$($a$)$ Briefly describe the steps of the fluidized bed drying process.

$($b$)$ Describe the scale$-$up considerations for scaling up a fluidized bed spray$-$coating process.

$($c$)$ Explain the challenges of spraying fine and highly concentrated suspensions. How can you resolve those issues?

$($d$)$ What are the advantages of using rotary atomizers for microstructured materials? Justify your answer.