The stability of an oil-based fluid crude oil fluid may be determined by measuring a first RI value of the crude oil that does not comprise a solvent where the first RI value is used to determine a first solubility parameter therefrom. The ECU may be a vehicle or non-vehicle ECU having any number of modules configured to provide andor support any number of operations. Also, the cap serves as the expanding cap for the soft tissue of gum to avoid the anesthetization surgery before the artificial tooth is placed.