CATHODIC  PROTECTION—  A method for pre- venting the corrosion of metals by electrolysis. CENTRIFUGAL—  Moving  or  tending  to  move  away from the center axis of a rotating or turning object. CENTRIFUGAL  PUMP—  A  rotating  device  that moves liquids and develops liquid pressure by im- parting  centrifugal  force. CENTRIFUGAL PURIFIER— A rotating device that cleans fuel by using centrifugal force. CLEAR AND BRIGHT—  Term  for  uncontaminated fuel; indicating a complete absence of haze, free water, or particulate matter that would be visible to the naked eye. CLEAVAGE—  The point of interface between two dif- ferent liquids, such as oil and water. CLOUD POINT— The temperature at which a fuel develops a cloudy or hazy appearance due to the precipitation of wax or moisture. COALESCER—  A tube (unit or element) that unites water  droplets  when  fuel  passes  through  it. COFFERDAM—  The space surrounding the MOGAS storage  tanks  aboard  ship;  a  watertight  box. COMBUSTIBLE LIQUID— A liquid having a flash- point at or above 100°F. COMMINGLING—  Tie mixture of two or more pe- troleum products resulting from improper handling, particularly  in  pipeline  or  tanker  operations. CONSOLIDATE—  To merge into one. To consolidate a nest of tanks means to pump the remaining fuel from several partially empty tanks into a single tank. CONTAMINATION—  The addition of some material not normally present in a petroleum product, such as dirt, rust, water, or another petroleum product. CONTINUITY— To have a complete, uninterrupted electrical  circuit. CORROSION—  The  process  of  dissolving,  especially of metals, due to exposure to electrolytes. CRUDE OIL—  Petroleum  in  its  natural  state. CV— Aircraft Carrier. CVN— Aircraft  Carrier  (nuclear-powered). DAY TANK— Fuel storage tank used for daily issue of fuel. DEADMAN CONTROL— A control device requiring manual operation, such as a switch or valve, de- signed to stop flow if the operator releases it. DIAPHRAGM—  Separating  device  of  rubber  compo- sition  used  to  regulate  all  hydraulically  operated valves. DIFFUSE— To  spread  widely,  scatter, DIFFUSER—  A mechanical device used to diffuse. DIKE— An embankment or wall, usually of earth or concrete, surrounding a storage tank to impound the tank’s contents in case of a leak or spill. DISSOLVED  WATER—  Water absorbed into the fuel that is not visible. The amount of dissolved water a fuel  will  hold  depends  upon  the  fuel’s  temperature. DISTILLATE— Common term for several fuels ob- tained  directly  from  distillation  of  crude  petroleum; typically includes kerosene, JP-5, light-diesel, and other  light-burner  fuels. DOUBLE-WALLED  PIPING—  Piping with two in- dependent chambers, one surrounding the other (an inner and an outer). Typically used in shipboard gasoline  systems.  The  inside  chamber  carries  the fuel, the outside chamber holds a protective gas (such as CO? or N?). DOWNGRADE—  To designate a fuel for a lesser pur- pose  than  originally  specified,  often  because  of contamination. EARTHING—  See GROUND. EDUCTOR—  A jet-type pump with no moving parts. An  eductor  moves  liquid  by  entraining  the  pumped liquid in a rapidly flowing stream of water (venturi effect).  Normally  used  to  dewater  bilges  and  tanks. EMULSION—  The suspension of fine droplets of one liquid in a second liquid with which the first will not mix. ENTRAINED  WATER—  Free-water  contaminant  in  a fuel in the form of very small droplets, fog, or mist. It may or may not be visible. EVAPORATE— To change into vapor. EVAPORATION LOSS— Loss of liquid petroleum into the atmosphere caused by evaporation. FILTER— A porous object through which a liquid is passed to remove unwanted particles of solid matter. AI-2