1. (General Engineering) tungsten-electrode inert gas welding: a method of welding in which the arc is maintained by a tungsten electrode and shielded from the access of air by an inert gas. Compare MIG welding.
A prescription for a controlled drug is valid for 28 days from the date given on the prescription. usually six months unless it's a controlled i.e. morphine, pethidine and methadone. These medicines are often misused, so have stricter legal controls on their supply to prevent them being obtained illegally. A prescription for a controlled drug is valid for 28 days from the date given on the prescription.
Usually, for a one month pair, it'll be usually about six months per prescription, or six contacts per case. Usually contact lens prescription is good for one year. After the year from when you had your eyes exam, the office or you yourself can make another exam to see if you can still see in your current prescription. 1 person found this useful.