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The high cost of powder feedstock has raised interest in recovering unmelted powder in the build chamber and its reuse in subsequent builds .
 machine or equipment: powder feedstock; material: powder; process parameter: build chamber; process characterization: builds
Given options, please tell me the categories of all the listed entity words.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} 
 Entities: powder feedstock, powder, build chamber, builds 
Answer:
 machine or equipment: powder feedstock; material: powder; process parameter: build chamber; process characterization: builds