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Pre- and post-test non-destructive analyses revealed that the primary source of the reduced properties and increased variability was attributable to heterogeneous surface topography with stresB-concentrating contours and commensurate reduction in effective load-bearing area .
 non-destructive analyses, primary source, properties, variability, heterogeneous, topography, stresB-concentrating, contours, reduction, load-bearing area
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:
 non-destructive analyses, primary source, properties, variability, heterogeneous, topography, stresB-concentrating, contours, reduction, load-bearing area