“…Previous investigation of the effect of q on ε by Brazier-Smith et al (18) and Kumar et al (21) showed that ε increases as q is different than 1 . On the other hand Adler (23,33), Mousa and van de Ven (24,34,35), Zhang et al (36), and Rother et al (19) found that the coalescence efficiency increases as the radii ratio approaches 1. It should be stated that this point is not yet complete and further investigation is needed.…”