The image shows steel water pipes connected to a flange with visible rust concentrated around the joint region.

a) Using a hand drawn sketch, show the likely oxygen concentration profile in and around the corroded joint and explain how this drives the corrosion. 

b) Suggest ONE preventive design and ONE maintenance strategy that you have learned in class, that could mitigate recurrence of this corrosion under similar service conditions. Justify how your strategy addresses the underlying cause.