Robotic Laser Welding

What degrees of freedom or how many joints does a laser welding robot have?...

What is the tool that firemen use to test for natural gas leaks in a home?

Recently there was a major natural gas line cut, and leak in my neighborhood. A fireman came to my home to test inside for natural gas. He carried an electronic tool to tell him if there was natural gas present in my home. What is this tool? How does it work? ...

What are good ways to prevent mold growth in an AC unit?

Noticing some mold in my AC unit and want to know how to prevent further growth....