Other kinds of welding. Some kinds of welding do not use an electric arc. They might use a flame, electricity without an arc, an energy beam, or physical force. The most common type of welding that does not use an arc is called gas welding.
TDW - Total Diamond Weight. A term usually used when there is more than one diamond in a particular piece of jewelry. The combined weight of all of the (diamond) stones.
The typical TDD is a device about the size of a typewriter or laptop computer with a QWERTY keyboard and small screen that uses an LED, LCD, or VFD screen to display typed text electronically.