The use of the vowel fatHa (or in English a) simply refers to the participant as being the one receiving the action as opposed to the use of kasra (or i in English) which denotes the participant doing the action rather than receiving it.

A hog, basher, hammermill or prebreaker is used to grind the bones, heads, feet, heavy tissues, and whole carcasses into pieces no larger than 2 inches.

Soy protein is used as a meat extender.

He farmed his marginal land with difficulty.