878
Moderate abrasive size and concentration led to a balance between the two mechanisms of surface roughness improvement .
 abrasive, led, surface roughness
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:
 abrasive, led, surface roughness