881
Average surface roughness , Ra , was reduced from as high as 6.5 μm on side surfaces ( 90° ) to 3.8 μm .
 concept or principle: Average; machanical property: roughness; material: as; material: as; concept or principle: surfaces
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: Average, roughness, as, as, surfaces 
Answer:
 concept or principle: Average; machanical property: roughness; material: as; material: as; concept or principle: surfaces