4435
In order to study the special constriction effect and physical process features during compulsively constricted WAAM ( CC-WAAM ) , the dynamic behaviours of arc , droplets , and molten pool were visually investigated .
 concept or principle: physical process; manufacturing process: WAAM; concept or principle: dynamic; concept or principle: arc; concept or principle: droplets; concept or principle: molten pool
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: physical process, WAAM, dynamic, arc, droplets, molten pool 
Answer:
 concept or principle: physical process; manufacturing process: WAAM; concept or principle: dynamic; concept or principle: arc; concept or principle: droplets; concept or principle: molten pool