Enhancing is a type of functioning process of meta-function. Both enhancing and improveing represents optional contribution to other function. The “optional” means that the effect of fa is not mandatory to ft, that is, the target function can be performed without improving or enhancing. The discrimination between improving and enhancing is made by whether augmentation of the output can be made without increase of the amount of the input energy or not. For example, the “to make low pressure” of the condenser contributes to the efficiency of the “to generate torque” function without increment of input energy, so its functioning is “Improving”. On the other hand, the “to super-heat” function of the boiler optionally increases the amount of the input energy to make a contribution. Its meta-function is “Enhancing” .

http://purl.obolibrary.org/obo/TXPO_0002542

http://purl.obolibrary.org/obo/TXPO_0002541