The battery terminals are represented as electron-source and electron-sink in the user interface of the models. The function of this variable is to stop the model once a certain number of electrons reach the battery positive, and a monitor displays the time taken to fill the electron-sink.
Australia faced the threat of communism after WWII ended in 1945. The threat was known as the Red Menace which was caused by all the conflicts in Asia and also things that were going on in Australia at the time. The Australian government responded to the Red Menace in many ways.
North Vietnam had also attacked American soldiers and sank an American ship, adding further reason for the United States to join the war. The Cold War brought fear of communism to Americans, especially in the 1950s. The threat of communism spreading prompted the United States to take military action in support of the South Vietnamese.