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Given its detrimental influence on mechanical properties , porosity defect is a major problem for wire + arc additively manufactured ( WAAM ) Al components .
 concept or principle: mechanical properties; machanical property: porosity; concept or principle: defect; manufacturing process: wire + arc additively manufactured; manufacturing process: WAAM; material: Al
Given options, please tell me the categories of all the listed entity words.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} 
 Entities: mechanical properties, porosity, defect, wire + arc additively manufactured, WAAM, Al 
Answer:
 concept or principle: mechanical properties; machanical property: porosity; concept or principle: defect; manufacturing process: wire + arc additively manufactured; manufacturing process: WAAM; material: Al