4490
Hot cracking occurred at high-angle grain boundaries and especially at low-angle grain boundaries .
 concept or principle: Hot cracking; concept or principle: grain boundaries; concept or principle: grain boundaries
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: Hot cracking, grain boundaries, grain boundaries 
Answer:
 concept or principle: Hot cracking; concept or principle: grain boundaries; concept or principle: grain boundaries