open punctuation is used in types of business letters. In a business letter you may address the letter, but instead of putting somthing like San Diego, California, you would put SAN DIEGO CALIFORNIA. there is no puctuation used in the address and it is in all caps.
Mixed punctuation actually means that you add a colon to the end of a salutation in your documents. Open means you do not add a colon; for example:Dear SusieThanks for calling!Whereas for mixed punctuation:Dear Susie:Thanks for calling!
Open
Gutters are normally open Sewer piping is closed
actuator is a mechanism that will responds to hydraulic,pneumatic and electrical signal ,it is used to control the valve that to be in open or close condition.
It all depends. Squirells can be very transient beings. Is the window open, or closed? It makes all the difference in the world.