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.
Operational units are organized under a TO&E. TDY stands for Temporary Duty. TDY means that a service member is not at his assigned unit, but is conducting operations or training at another location or with another unit (such as attending a military school).