8820
In beam element flexure however , the octet beams had the highest strength , 1.9 GPa , four times stronger than the Kelvin beam elements and 500 times stronger than the octet bulk structure .
 beam, flexure, strength, GPa, beam, structure
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:
 beam, flexure, strength, GPa, beam, structure