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An in situ powder mixing system was designed to mix both metal and glass powders at selective ratios and the mixed powders were dispensed with an ultrasonic vibration powder feeding system with multiple nozzles .
 in situ, mixing, designed, metal, glass, powders, ultrasonic vibration powder feeding system, nozzles
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:
 in situ, mixing, designed, metal, glass, powders, ultrasonic vibration powder feeding system, nozzles