Article Per Year (5 Year)
p-Index From 2021 - 2026
0.817
P-Index
This Author published in this journals
All Journal Rekayasa Mesin Makara Journal of Science Makara Journal of Technology Jurnal Sains Materi Indonesia
Wahyu Bambang Widayatno, Wahyu Bambang
Lembaga Ilmu Pengetahuan Indonesia (LIPI)
Chemical Engineering, Chemistry & Bioengineering Civil Engineering, Building, Construction & Architecture Electrical & Electronics Engineering Engineering Industrial & Manufacturing Engineering Materials Science & Nanotechnology Mechanical Engineering

Published : 6 Documents Claim Missing Document
Claim Missing Document
Check
Articles

Found 2 Documents
Search
Journal : Makara Journal of Science

 1 
Effect of Mechanical Milling on the Total Phenolic Content and Antioxidant Activity of Garcinia mangostana Pericarp Nugroho, Dwi Wahyu; Daratika, Dyah Ayu; Kamila, Muthia; Togatorop, Lusiana; Rifada, Mohammad Aulia; Widayatno, Wahyu Bambang; Maulana, Syahrizal; Setyawati, Damai Ria; Mardliyati, Etik; Rochman, Nurul Taufiqu
Makara Journal of Science Vol. 24, No. 2
Publisher : UI Scholars Hub

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

This study aimed to identify the effect of mechanical milling on the total phenolic content and antioxidant activity of mangosteen pericarp. Mangosteen pericarp was milled under different milling times (30, 90, 150, and 210 min). The particle morphology before and after milling was observed by scanning electron microscopy (SEM), and the average particle size was obtained from SEM images and analyzed statistically. The antioxidant activity was measured through the 2,2-diphenyl-1-picrylhydrazyl method. The total phenolic content for the non-milling sample was 14.52 × 104 µg GAE/g sample, and the highest total phenol content was 17.44 × 104 µg GAE/g sample for the sample milled for 210 min. The IC50 value decreased for samples with milling 150 and 210 min, which showed strong antioxidant activity, whereas the value of gallic acid equivalent increased. SEM observations showed the presence of agglomeration in the morphology of mangosteen pericarp samples. The average particle size of the mangosteen pericarp decreased as the milling time increased (up to 4499 nm for samples milled for 210 min). Therefore, mechanical milling had a significant effect on the phenolic content and antioxidant activity, which indicated an increase in the bioavailability of mangosteen pericarp.
Key Deposition Parameters for Short-type ZnO Nanosheets Electrodeposited Under Galvanostatic Mode Ensang Timuda, Gerald; Harjanto, Dhimas; Widayatno, Wahyu Bambang
Makara Journal of Science Vol. 24, No. 3
Publisher : UI Scholars Hub

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Studies on the deposition of ZnO nanosheets grown vertically and perpendicular to conductive substrates have been conducted to obtain tall-type nanosheets (approximately 15 µm in height). However, some applications require short-type nanosheets with a height of about 1µm or less. In this study, short-type ZnO nanosheets were electrodeposited on indium-doped tin oxide substrates under galvanostatic (constant current) mode for a short deposition time. Then, the key parameters to form nanosheet layers with a height in the micrometer order and with good coverage were evaluated. Deposition was performed at 1 mA/cm2 for 60 s. Ar gas was initially bubbled into the electrolyte solution during electrodeposition to remove oxygen. Then, the solution was compared with solutions that did not undergo bubbling. Various electrolyte compositions (various concentrations of acetate and nitrate) were observed in solutions under the non-Ar bubbling condition. Moreover, the oxygen in the solution remarkably affected the morphology of the nanosheet, which became much denser and taller. Therefore, altering electrolyte composition affects morphology, although the effect is not as significant. Electrolyte composition must be optimized to produce the desired short and dense nanosheets because a low concentration of each anion leads to the production of a non-nanosheet layer, whereas a high concentration causes reduction in the density coverage of the nanosheet. A complete discussion of this phenomenon is presented in this study.
Co-Authors Abdul Basyir, Abdul Agus Sukarto Wismogroho, Agus Sukarto Akhiruddin Maddu Amal, Muhamad Ikhlasul Daratika, Dyah Ayu Didik Aryanto Dwi Wahyu Nugroho Ensang Timuda, Gerald Etik Mardliyati, Etik Firdarini, Cherly Firdharini, Cherly Harjanto, Dhimas Husin Alatas Jayadi Jayadi Jayadi Kamila, Muthia Maulana, Syahrizal Mulya, Marga Asta Jaya Noviyanto, Alfian Nurul Taufiqu Rochman Rifada, Mohammad Aulia Sari, Yessie SETYAWATI, DAMAI RIA Sri Harjanto Togatorop, Lusiana Yessie Widya Sari