1825
The third example is a case study from the aerospace industry , in particular the optimization of a mechanical hinge for an Airbus A320 by the European Aeronautic Defence and Space Innovation Works in this case a 75 % mass reduction was realized .
 concept or principle: case study; application: aerospace industry; concept or principle: optimization; application: mechanical; application: Airbus A320; concept or principle: reduction
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: manufacturing standard, machanical property, manufacturing process, material, engineering feature, process parameter, machine or equipment, application, process characterization, enabling technology, biomedical, concept or principle 
Text: {0} 
Answer:
 concept or principle: case study; application: aerospace industry; concept or principle: optimization; application: mechanical; application: Airbus A320; concept or principle: reduction