9022
Several studies were performed , including shrinkage analysis , porosity measurements , and mechanical compression tests to quantify the effect of layer thickness on part quality and mechanical properties .
 shrinkage, porosity, mechanical, compression tests, layer thickness, quality, mechanical properties
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:
 shrinkage, porosity, mechanical, compression tests, layer thickness, quality, mechanical properties