Freight Surcharges. BAF refers to floating part of sea freight charges which represents additions due to oil prices. Usually BAF charges are determined by Carrier Conferences to be applicable for a certain period on a certain trade route. These Carrier Conferences are seen as a cartel for fixing prices.
Heat transfer. Heat transfer is a discipline of thermal engineering that concerns the generation, use, conversion, and exchange of thermal energy (heat) between physical systems. Heat transfer is classified into various mechanisms, such as thermal conduction, thermal convection, thermal radiation, and transfer of energy by phase changes.
The last method heat transfer would be convection. This is the transfer of heat through fluid or air currents. As something heats up, the particles will spread out and thus become less dense. An example of convection would be a pot of water starting to boil on a stove.