2680
Two strengths were computed : an effective structural strength defined as the total force that the structure withstood normalized by the full crosB-sectional area , and a ligament structural strength , defined as the effective structural strength normalized by the density of the solid material , thereby ignoring the volume of the surrounding powder and voids that do not contribute to the strength of the lattice .
 strengths, strength, as, force, structure, area, strength, as, strength, density, material, volume, powder, voids, strength, lattice
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:
 strengths, strength, as, force, structure, area, strength, as, strength, density, material, volume, powder, voids, strength, lattice