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A simulation model for the gas flow and the powder particle flow between the powder nozzle and the melt pool surface has been developed , which reveals the volume percentage of different gas types and so the quality of the shield gas atmosphere .
 enabling technology: simulation; concept or principle: model; concept or principle: gas; material: powder particle; material: powder; machine or equipment: nozzle; material: melt pool; concept or principle: volume; concept or principle: gas; concept or principle: quality; concept or principle: gas
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: simulation, model, gas, powder particle, powder, nozzle, melt pool, volume, gas, quality, gas 
Answer:
 enabling technology: simulation; concept or principle: model; concept or principle: gas; material: powder particle; material: powder; machine or equipment: nozzle; material: melt pool; concept or principle: volume; concept or principle: gas; concept or principle: quality; concept or principle: gas