background
construction
control
energy
engineer
engineering
engineering design
equipment
factory
faucet
fuel
gas
gasoline
gate
grunge
high
industrial
industry
knob
line
machanic
machine operator
machine parts
machine tools
management
metal
nobody
object
oil
old
petroleum
pipe
pipeline
pipes
piping
plumbing
power
pressure
pump
red
resolution
sewer
steel
system
technology
tube
valve
valves
water
wheel