1899
In this above-mentioned study the experimental elastic modulus values were significantly lower than predicted mostly attributed to surface roughness and irregularity which creates stress concentrations in notches and in locations of very thin wall thickness .
 concept or principle: experimental; machanical property: elastic modulus; concept or principle: predicted; machanical property: surface roughness; process characterization: stress concentrations; engineering feature: notches; engineering feature: wall thickness
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:
 concept or principle: experimental; machanical property: elastic modulus; concept or principle: predicted; machanical property: surface roughness; process characterization: stress concentrations; engineering feature: notches; engineering feature: wall thickness