4). a) Construct the Attainable Region boundary from the following data of a batch milling process. The data represents sieve data so "mass retained" refers to the mass of material that was retained on a given sieve i.e. material on the 400m sieve is material that is larger than 400m. The desired size class is particles with sizes between 200m to 400m. Plot the attainable region boundaries and determine the maximum amount of the desired size class that can be achieved for each data set. Excel spread sheets with the data below are available on the course website. Data Set One: Mass with time data for a specific energy input of 6J/g/s (Data Set One tab) Data Set Two: Mass with time data for a different specific energy input (Data Set Two tab) b) Based on the Attainable Region boundaries of both data sets, is the experiment for data set 2 performed at a lower or higher energy input? Which energy input would you use to maximize the desired size class