This journal is an open access journal which provides immediate, worldwide, barrier-free access to the full text of all published articles without charge readers or their institutions for access. Readers have right to read, download, copy, distribute, print, search, or link to the full texts of all articles in CHEMICA: Jurnal Teknik Kimia. This journal provides immediate open access to its content on the principle that making research freely available to the public supports a greater global exchange of knowledge.