VNUHCM Journal of Engineering and Technology 2024-07-16T19:44:17+07:00 Mai Thanh Phong Open Journal Systems Effect of secondary emulsion parameters on Gac oil encapsulation by gelatin in double emulsion 2024-07-16T04:54:47+07:00 Ngoc Thi-Minh Ta Dang Hai Tran <p>Gac oil was encapsulated in gelatin using the oil in water in oil (o/w/o) double emulsion method. The o/w single emulsion was formed by homogenizing Gac oil with gelatin solution and dispersing into liquid paraffin to form the o/w/o double emulsion. Microcapsules were stabilized by lowering the temperature of the double emulsion to a temperature below the gelatin’s gelation point. Effects of parameters, including temperature and stirring speed, on encapsulation yield, encapsulation efficiency and microcapsule size were investigated. The results show the highest encapsulation yield of 93.47 %, with encapsulation efficiency of 86.49 % and microcapsule size of 156 µm. The difference in temperature between single emulsion and paraffin reduced the encapsulation yield by 6.74-12.88 %. The size of microcapsules decreased as the temperature of single and double emulsions increased. Besides, increasing the stirring speed during the formation of the double emulsion reduced microcapsule size and encapsulation yield. Otherwise, the encapsulation yield was not affected by all investigated conditions. The microcapsules were spherical with size deviation. Microcapsules surface was continuous with irregularities or wrinkles.</p> 2024-06-30T00:00:00+07:00 ##submission.copyrightStatement## Effects of prestressing force on column, frame consider construction and tensioning sequence 2024-07-16T19:44:17+07:00 Cong Thanh Pham <p>Currently, prestressed concrete floors are the familiar concept in construction industry, wide application and understanding about them are comprehensive. However, the effects of prestressing force on column have not concerned. The paper presents the effects of prestressing force on column, frame in prestressed concrete structure associated with construction and tensioning sequence. And by expanding basic equations of presstressed concrete structure to explain the dependence of internal force on construction and tensioning sequence is also presented in this paper. Besides, the paper introduces the way to simulate and analyse the tendons in global model Etabs (nonlinear staged construction) for gaining a reasonable result in accordance with construction and tensioning sequence in practical design. The simulation in global model determines effect of prestressing force on not only slab but also column, frame; And nonlinear staged construction analysis to consider effect of construction and tensioning sequence to distribute internal forces on story, column and frame associated with construction sequence. The behaviors of the column include bending, shear, tension (compression) due to prestressing force easily determine before combination with other actions in design.</p> 2024-06-30T00:00:00+07:00 ##submission.copyrightStatement##