1824
Since some processes can be slightly heterogeneous in nature , accounting for shrinkage may require careful preparation and difficult to precisely control .
 concept or principle: processes; material: be; concept or principle: heterogeneous; concept or principle: shrinkage
Please list all entity words in the text that fit the category.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} 
Answer:
 concept or principle: processes; material: be; concept or principle: heterogeneous; concept or principle: shrinkage