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
But in order to sell it, you may have to discount it, promote it or mark it down for clearance at the end of the season. Gross margin is the profit you actually earn when you sell it after any discounting or markdowns; it is frequently called maintained margin. This spread will be specific to your business, depending upon your level of promotional and clearance activity. Margin erosion will naturally occur unless you actively manage your markup percentages. Several factors can cause overall margins to erode, including: competitive price pressures forcing below-standard markups; vendor price increases pushing retail prices up against natural price points; and unanticipated shifts in sales mix toward lower-priced and lower-margin merchandise.