@rabhishek91
I assume English is not your first language and complement you on your excellent understanding of it. In particular, it is clear that you understood the word, "Sir," has many uses. By far the most common use is to address a man in polite and casual speech. It is also used correctly in more formal situations, such as business correspondence and legal documents. Of course, in the military, Sir is used when referring to a person of higher military rank. It can also be used in referring to a man of lower rank and to non-military men as a show of respect. In aviation, you will almost never hear male controllers and pilots refer to each other by any word other than "Sir."
What is most surprising about the petty and offensive tirade by April (Post #18) criticizing your correct use of the word is that English is probably her first and perhaps only language. Why she picked this particular thread from among all the others on ETO in which "Sir" is used is a mystery.
I hope you have made progress in finding sensors for animal smells.
Regards,
John