#diffusion  (physics) the process of diffusing; the intermingling of molecules in gases and liquids as a result of random thermal agitation
  supertype:  natural_process__naturalproces__natural_action__naturalaction__action__activity  a process existing in or produced by nature (rather than by the intent of human beings); "the action of natural forces"; "volcanic activity"
  subtype:  osmosis__osmosi  diffusion of molecules through a semipermeable membrane from a place of higher concentration to a place of lower concentration until the concentration on both sides is equal
  subtype:  permeation__pervasion__impregnation__saturation__suffusion  the process of permeating or infusing
     subtype:  ammonification  impregnation with ammonia or a compound of ammonia
     subtype:  carbonation  saturation with carbon dioxide (as soda water)
  subtype:  transport  an exchange of molecules (and their kinetic energy and momentum) across the boundary between adjacent layers of a fluid or across cell membranes
     subtype:  active_transport  transport of a substance (as a protein or drug) across a cell membrane against the concentration gradient; requires an expenditure of energy
     subtype:  passive_transport__passivetransport  transport of a substance across a cell membrane by diffusion; expenditure of energy is not required

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