1099
The optimisation of a heat sink design displayed the software 's capabilities to deal with multi-objective optimisation , as the design variables included friction force , thermal conductivity and out-of-plane heat transfer , besides the density of the elements .
 machine or equipment: heat sink; engineering feature: design; concept or principle: software; material: as; engineering feature: design; concept or principle: friction force; machanical property: thermal conductivity; concept or principle: heat transfer; machanical property: density; material: elements
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:
 machine or equipment: heat sink; engineering feature: design; concept or principle: software; material: as; engineering feature: design; concept or principle: friction force; machanical property: thermal conductivity; concept or principle: heat transfer; machanical property: density; material: elements