<![CDATA[This study investigated predictive modeling of changes in B35 biodiesel fuel characteristics treated with ultrafine bubbles (UFB) during storage. B35 biodiesel, consisting of 35% palm oil biodiesel and 65% diesel fuel, has been widely implemented in Indonesia as part of the national renewable energy program. However, maintaining fuel quality and stability during storage remains a major challenge. In this study, B35 biodiesel samples were treated with oxygen injection using UFB technology at durations of 10, 20, and 30 minutes and stored for seven weeks under controlled conditions. Fuel characteristics, including kinematic viscosity, density, water content, total acid number, and oxidation stability, were evaluated weekly. The results showed that increasing UFB injection duration tended to increase kinematic viscosity, density, and total acid number, while water content and oxidation stability tended to decrease during storage. The developed predictive models generally exhibited polynomial regression patterns. The models demonstrated good predictive performance for density, water content, and oxidation stability, whereas the predictive performance for viscosity was relatively lower. One-way ANOVA indicated that UFB injection duration had no significant effect (P > 0.05) on viscosity, density, or total acid number, but significantly affected water content and oxidation stability (P < 0.05). These findings provide important insights into the storage stability of B35 biodiesel fuel treated with UFB technology.]]>
