Bulk
Bulk turns up in 2 fields: paper optics, logistics. Here is what it means to the people in each one.
Bulk in paper optics
Volume per unit mass of paper, the inverse of density, usually given in cubic centimeters per gram.
Calculated as caliper divided by grammage, bulk tells how thick a sheet is for its weight. High-bulk sheets hold more internal air and free fiber surface, so they scatter more light and give better opacity per gram. Refining, wet pressing and calendering all lower bulk, which is why mills fight to keep it while chasing strength and smoothness.
"Bulk is 1.35 on this lot, a good tenth above the last trial, and the opacity followed it up."
Bulk in logistics
Unpackaged, loose cargo transported in large volumes rather than in individual containers or pallets.
Bulk freight consists of raw materials or commodities that are transported loose in the hold of a ship, a rail car, or a tanker truck. This category includes dry materials like grain, coal, and gravel, as well as liquid goods like petroleum and chemicals. Logistics operators handle these materials using specialized equipment like pumps, augers, and conveyor belts rather than forklifts or cranes.
"We need a pneumatic trailer to haul this bulk cement out to the new highway project."