1650
Two types of spatter were identified which were droplet spatter , generated by the tearing behaviour of molten metal and powder spatter , which are produced when non-metallic powder particles around the molten pool are blown away as a result of metallic vapour impact .
 process characterization: spatter; process characterization: droplet spatter; material: molten metal; process characterization: powder spatter; material: powder particles; concept or principle: molten pool; material: as; material: metallic; concept or principle: impact
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:
 process characterization: spatter; process characterization: droplet spatter; material: molten metal; process characterization: powder spatter; material: powder particles; concept or principle: molten pool; material: as; material: metallic; concept or principle: impact