Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_28744929_1 (joined_acc VARCHAR, location VARCHAR)

### Question ###
when did the institution at chapel hill, North carolina join acc?

### Accurate SQL ###

SELECT joined_acc FROM table_28744929_1 WHERE location = "Chapel Hill, North Carolina"