6127
The arithmetic average roughness , Ra , was measured using a surface roughness tester , and optimum conditions for achieving the lowest roughness for both up-skin surfaces and down-skin surfaces have been obtained .
 concept or principle: average; machanical property: surface roughness; machanical property: roughness; concept or principle: surfaces; 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, surface roughness, roughness, surfaces, surfaces 
Answer:
 concept or principle: average; machanical property: surface roughness; machanical property: roughness; concept or principle: surfaces; concept or principle: surfaces