Nyob rau hauv dav dav, txhim kho lub npoo log hub yog thawj kauj ruam los txhim kho kev ua haujlwm ntawm lub tsheb. Txawm li cas los xij, cov kws tshaj lij nyob rau hauv cov npoo tsheb cov tuam txhab nco txhua tus neeg thaum txhim kho, nco ntsoov them sai sai rau ob lub ntsiab lus no:
Ua ntej, qhov kev hloov kho tshwj xeeb: nyob rau hauv qhov kev pom zoo ntawm daim ntawv tso cai, thawj lub tsheb npoo lub log tsheb tshwj xeeb yog nce qib upwards, uas yog, lub npoo qhov tshwj xeeb yog nce. Ntxiv nrog rau kev txhim kho tuav, lub hom phiaj ntawm txoj hauv kev no yog ntawm chav kawm kom ua rau tag nrho cov tsheb tom qab lub nplhaib hlau zoo nkauj dua thiab muaj zog dua. Feem ntau, thaum txhim kho qhov tshwj xeeb, qhov zoo yog hloov kho dua tshiab.
Thib ob, qhov kev txhim kho kom zoo: tswj qhov tshwj xeeb ntawm thawj qhov kev txhawb nqa lub nplhaib steel, tab sis hloov mus rau theem siab dua ntawm cov hlau nplhaib txhawm rau txhim kho kev ua tau zoo ntawm cov hlau ntiv nplhaib, xws li zoo nkauj dua steel nplhaib txawv, zoo dua cov kua, yob ua kom nrov dua, lossis muaj zog tuav, thiab lwm yam.
Hauv ntej, kev txhim kho ntawm cov nplhaib muaj hlau ntau zaus yog qhov tseem ceeb los ua kom nce qib loj dua mus rau kev ua haujlwm tag nrho ntawm lub tsheb. Nws tseem yog qhov kho kom ncaj qha rau tus tswv, tsis hais txog qhov pom pom lossis cuam tshuam nrog kev cuam tshuam.
