The beginning of the amazing events at Krakatoa in 1883 date to May 20 when there were initial rumblings and venting from the volcano, which had been dormant for about 200 years.
A refinery margin is the revenue associated with refining petroleum, expressed as a value per volume (e.g. $/L), net of the cost of the crude oil input. The simplest refining
Gross Margin is a calculation of revenue less cost of goods sold, and is used to determine how well sales cover direct variable costs relating to the production of goods. Net income/sales, or profit margin, is calculated by investors to determine how efficiently a company turns revenues into profits.