About 22% of the energy used in the U.S. comes from natural gas. There are about 300,000 miles of natural gas pipelines in the lower 48 states and 425,000 gas producing wells. The history of natural gas.
thru-hole. A circuit board packaging technique in which the leads (pins) on discrete components and chips are inserted through holes in the printed circuit board and soldered from beneath.
The term is still used today in plumbing, where a funnel or hopper is filled by an outlet pipe above it. This is often provided for intermittent overflows, or where an air gap is required, to avoid possible back-contamination. In metal casting, a tundish is a broad, open container with one or more holes in the bottom.