Hauv kev ua cov khoom lag luam roj hmab, xws li cov txheej txheem (xws li cov teeb meem dej, feem ntau yog cov khoom siv tawm, thiab cov khoom hnav sai. Tshwj xeeb tshaj yog rau cov roj hmab elastic thiab viscous roj hmab lev
Lub tuam txhab muaj lub zog muaj zog thiab lub koob npe zoo. Cov khoom siv tau muab tus nqi ua tau zoo. Tseem ceeb tshaj plaws, lawv tuaj yeem ua tiav txoj haujlwm hauv lub sijhawm, thiab tom qab kev pabcuam muag khoom yog qhov chaw.