IOWA CITY — They can feel worlds apart.Town and gown. Community members and college students. Iowa City parents hovering over toddlers screeching and squinting in the Pedestrian Mall splash pad versus twentysomethings scurrying to class, ducking into coffee shops and bar hopping as the days trade shifts overnight. But one University of Iowa professor has and continues to contend — through initiatives, like his recent “Green Room” project that engaged thousands of community members with one of his classes — that more unites the two camps than divides them.