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Recently , such monitoring , feedback , and control have been made possible by implementing in situ infrared ( IR ) thermography in powder bed fusion AM technologies .
 feedback, in situ, IR, powder bed fusion AM technologies
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:
 feedback, in situ, IR, powder bed fusion AM technologies