takeOwnership() this method results in the authenticated user running the script to take ownership of the node.
Example
If running the script while authenticated as admin, the following code would result in admin being returned as the owner.
var node = companyhome.childByNamePath("TEST_FILE_0.TXT");
node.setOwner("fred.bloggs"); // owner is now 'fred.bloggs'
//...
node.takeOwnership(); // currently authenticated user running script is 'admin'
model.owner = node.getOwner();