Naphthenic acid by a general formula CH O, where "n" indicates the carbon number and "z" specifies a homologous series. The "z" is equal to 0 for saturated, acyclic acids and increases to 2 in monocyclic naphthenic acids, to 4 in bicyclic naphthenic acids, to 6 in tricyclic acids, and to 8 in tetracyclic acids. Salts of naphthenic acids, called naphthenates, are widely used as hydrophobic sources of metal ions in diverse applications.Aluminium salts of naphthenic acid and palmitic acid were combined during World War II to produce napalm. The word "napalm" is derived from the words naphthenic acid and palmitic acid.
Foam weapon Europe and the UK, the terms "latex weapon" and "LARP-safe weapon" are more common, and combat is usually referred to as "LARP combat". Non-latex foam weapons are primarily used in Jugger and in the Finnish LARP community. The primary concern in designing a foam weapon is safety; a pulled blow with a foam weapon should not hurt the target, and in systems that allow it, even a full-strength blow should not cause injury. Combatants who consistently fail to pull their blows are liable to be ejected from an event, or at least pulled out of the fighting for safety reasons.