3891
Parts were characterized using ex situ scanning electron microscopy ( SEM ) to validate data identified defects and , critically , to estimate detection success .
 scanning electron microscopy, SEM, data, defects
Please list all entity words in the text that fit the category. Output format is "word1, 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:
 scanning electron microscopy, SEM, data, defects