LOWELL — UMass Lowell officially welcomed the Class of 2029 with a convocation ceremony at the Tsongas Center Tuesday morning as a new slate of freshman students prepares to begin classes this week. More than 3,300 new students have enrolled at UML for the new school year, and many of them were seated in the Tsongas Center Tuesday morning to hear advice and be welcomed to their next chapter in life by former students, current students and UML leadership.