I need to understand an equation

Job ID: 36733308

Budget: $10 – $30 USD

I am looking for someone who can help me understand an equation and do a simple calculation for me.
The two equations are in the PDF file and used to extract Fig 3. Moreover, there is a calculated excel file with the values but I don't know how are they calculated. I need to understand how these values are calculated and calculate the size for a bubble with initial diameter of 75 nm at 25 degree-Celsius and 120 degree-Celsius at two pressures 3.06 and 6.12 atm meaning 4 calculations.