1. 
   NDIR
   acronym: non-dispersive infrared gas analyzer
   Found op http://cdiac.ornl.gov/pns/acronyms.html#N
   
   
2. 
   NDIR
   Non-Dispersive Infrared
   Found op http://www.e2v.com/assets/media/files/documents/imaging-space-and-scientifi
   
   
3. 
   ndir
   1) Non-dispersive infrared gas analyzer
   Found op http://www.mijnwoordenboek.nl/EN/crossword-dictionary/ndir/1
   
   

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