Ⅰ.Amagqabantshintshi Kwizityalo zamandla obushushu, iisistim zepetrochemical, ulwelo oluphezulu-viscosity kushishino lwekhemikhali yamalahle, ulwelo oluxubeneyo nothuli kunye namasuntswana aqinileyo, kunye nolwelo oludlaka kakhulu, iivalvu zebhola kufuneka zisebenzise iivalvu zebhola ezitywinwe ngentsimbi, ngoko khetha intsimbi efanelekileyo eqinileyo. iivalve zebhola ezitywiniweyo.I...
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