Article Per Year (5 Year)
p-Index From 2020 - 2025
1.235
P-Index
This Author published in this journals
All Journal Indonesian Journal of Chemistry Journal of Community Service and Empowerment Indonesian Journal of Chemical Studies (Indones. J. Chem. Stud.) International Journal of Applied Mathematics, Sciences, and Technology for National Defense
Prasojo, Agus Eko
Unknown Affiliation
Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Computer Science & IT Mathematics Physics Social Sciences Other

Published : 7 Documents Claim Missing Document
Claim Missing Document
Check
Articles

Found 7 Documents
Search

 1 
Iron determination in multivitamin tablets: Enhancing military nutritional preparedness based linear regression method Prasojo, Agus Eko; Anitasari, Reza; Sijabat, Windy Nelasari; Nurrosyid, Naufan
International Journal of Applied Mathematics, Sciences, and Technology for National Defense Vol 1, No 2 (2023): International Journal of Applied Mathematics, Sciences, and Technology for Natio
Publisher : FoundAE

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.58524/app.sci.def.v1i2.165

Abstract

AAS is also an important method that has the most extensive application in metal analysis. most of the determinations were carried out by thin spectrophotometry, therefore an experiment was carried out to determine the Fe content in multivitamin tablets using the atomic absorption spectrophotometry method has high selectivity and sensitivity. Standard solution preparation. Prepare a standard solution of Fe with a concentration of 1, 2, 3, 4, and 5 ppm, then read the absorbance of the standard solution on AAS. Sample solution preparation and absorbance measurement. Several tablets were put into a beaker and 7 ml of concentrated HCl was added working principle of atomic absorption spectrophotometry is based on the evaporation of the sample solution which will initially be nebulized to form a spray, then it will be desolvated to form a dry aerosol until it is evaporated and converted into free atoms.. Iron levels in samples using AAS can be found by measuring the intensity of the radiation that decreases after being transmitted. The reduction in radiation intensity is proportional to the concentration of the sample element in the sample being measured. By testing the t-test, it was found that the AAS instrument was more sensitive to low concentrations
Light Pyrotechnics Using Gunpowder Derived from Fly Ash Bottom Ash (FABA) Waste and Activated Carbon Siregar, Fuad Idris; Prasojo, Agus Eko; Julianingrum, Shavira Triana; Aulia, Desi Rahma Yanti; Wardha, Sophia Nafisa; Gita, Mutiara
Indonesian Journal of Chemical Studies Vol. 3 No. 1 (2024): Indones. J. Chem. Stud., June 2024
Publisher : Indonesian Scholar Society

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55749/ijcs.v3i1.42

Abstract

Pyrotechnic materials are a category of materials that are often used in various applications, including military activities, lighting, signaling, and combat effects. In this study, an experiment was conducted to create a light pyrotechnic material using gunpowder, which is a mixture of potassium nitrate, sulfur, and activated carbon. The manufacturing process involved the activation of carbon from fly ash bottom ash (FABA) waste and the composition of different pyrotechnic materials. The experiment involved testing pyrotechnic compositions with varying ratios of KNO3 : carbon : sulfur. The results showed that the composition with a ratio of 15 : 7.5 : 7.5 produced the highest light intensity, reaching 104 lux, and provided optimal visual effects. In addition, the relative proportions of oxidizer, carbon and sulfur affected the type of pyrotechnic effect produced. Pyrotechnic light generation from gunpowder could be considered successful, and the best composition for spectacular visual effects was a ratio of 15 : 7.5 : 7.5. However, sufficient caution and knowledge were required in the use of pyrotechnic materials to ensure safety and compliance with applicable regulations.
Enriching of society’s understanding of command-oriented leadership through an interactive virtual discussion Fahri, Mirad; Stiawan, Elva; Ariyanti, Dita; Basuki, Rahmat; Apriliyanto, Yusuf Bramastya; Hasibuan, Anggi Khairina Hanum; Kurniadi, Tedi; Putra, M. Sulthon Nurharmansyah; Septaningsih, Dewi; Tiarani, Sekar Ilma; Mayori, Ersha; Wiana, Regita Andriani; Yunita, Amalia; Nurrosyid, Naufan; Prasojo, Agus Eko; Putri, Riyanti
Journal of Community Service and Empowerment Vol. 5 No. 2 (2024): August
Publisher : Universitas Muhammadiyah Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22219/jcse.v5i2.27961

Abstract

In the post-pandemic era, many interactive activities have been flexibly generated through virtual conditions. Accordingly, some problems could appear in terms of leadership, such as difficulties in maintaining the audience’s attention during the event. Thus, the utilization of a command-based leadership style that could straightforwardly maintain audience focus ought to be considered to be adopted. However, both the command-based leadership style and its prospective aspects have not been widely understood by society. This community service aims to deliver a proper understanding of the command-based leadership style through interactive virtual discussion between experts in teaching activities of defense-based science and society consisting of Indonesian teachers, high school students as well as academics. Statistical results of pre-test and post-test scores showed enhancement of the participants’ understanding of command-based leadership. Hopefully, some relevant aspects of their new perspective of command-based leadership can be properly adopted and effectively implemented to answer current challenges, such as in terms of managing people in virtual conditions. 
Comparative Analysis of FABA Waste Composition in Various Coal-Fired Power Plant Industries in Several Countries and Indonesia: A Review Putra, M. Sulthon Nurharmansyah; Prasojo, Agus Eko; Budiman, Anggito; Anty, Mentari Zikri; Hasnowo, Lutfi Aditya
Indonesian Journal of Chemical Studies Vol. 3 No. 2 (2024): Indones. J. Chem. Stud., December 2024
Publisher : Indonesian Scholar Society

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55749/ijcs.v3i2.58

Abstract

Fly Ash and Bottom Ash (FABA) is the waste from burning coal in coal-fired power plants and consists of chemical compounds, such as SiO₂, Al₂O₃, Fe₂O₃, and CaO. This waste poses an environmental challenge and an opportunity for the construction industry. This study conducted a comparative analysis of the composition of FABA from several coal-fired power plants in Indonesia and other countries, such as Thailand, China, Malaysia, France, Italy, and Portugal. In particular, this study assessed the XRF data from several other references. The XRF test data showed significant variations in the FABA content, influenced by coal type, combustion method, and emission management technology. The high SiO₂ content in the Cirebon and Teluk Sirih coal-fired power plants showed potential for pozzolanic applications. Meanwhile, the high Fe₂O₃ in Tanjung Enim and Sudimoro had the potential for metallurgical applications. In addition, the high CaO content of Teluk Sirih allowed its use in lime production and soil stabilization. However, high levels of SO₃, especially in Cirebon, required more attention in processing because of its impact on concrete quality and environmental pollution. With proper processing, FABA could be a valuable resource in various industries, reducing reliance on natural raw materials. This study highlighted the potential for the sustainable use of FABA and proposed management measures to address environmental challenges. The optimal use of FABA reduced negative environmental impacts and opened up significant economic opportunities, supporting the circular economy in the energy and construction sectors.
Immobilization of Cerium(IV) Oxide onto Reduced Graphene Oxide in Epoxy Resin Matrix as Radar Absorbing Composite for X-band Region Bolilanga, Patricya Inggrid Wilhelmina; Basuki, Rahmat; Apriliyanto, Yusuf Bramastya; Prasojo, Agus Eko; Lazuardy, Ardyan; Anitasari, Reza; Putri, Riyanti; Sasongko, Nugroho Adi; Santiko, Arief Budi
Indonesian Journal of Chemistry Vol 24, No 6 (2024)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/ijc.94404

Abstract

The rGO/CeO2/epoxy composite has been successfully prepared as radar absorbing material (RAM) for the X-band (8–12 GHz) region. The reduced graphene oxide (rGO) originated from pencil graphite oxide (GiO) was synthesized through the modified Hummer method. The synthesis of rGO/CeO2/epoxy was conducted by immobilization of cerium(IV) oxide into rGO (rGO/CeO2) via hydrothermal method and followed by composited the rGO/CeO2 with epoxy resin matrix. Morphological analysis by SEM-EDX indicates that the rGO/CeO2 structure appears to be a tangled layer of edges randomly aggregated, and CeO2 is uniformly anchored on the rGO surface. From the diffractogram result of the XRD instrument, rGO exhibits changes in crystallinity, indicating a transformation of the interlayer structure from multilayer GiO to a single layer of rGO. The presence of Ce–O was indicated at wavenumber 553 cm−1 of rGO/CeO2 by FTIR. The microwave absorbing performance of rGO/CeO2/epoxy conducted by vector network analyzer (VNA) showed that the RL value of the composite was −3.22 dB (47% of electromagnetic wave absorption) at a frequency of 9.25 GHz at the thickness of 1 mm composite. The composite has the promising prospect of being developed as a captivating candidate for the new type of microwave absorptive materials.
Reflection Loss Improvement by Cerium Addition in Chitosan-Hydroxyapatite Film as Stealth Drone Candidate Putri, Riyanti; Prasojo, Agus Eko; Lazuardy, Ardyan; Anitasari, Reza; Salsabila, Fidela Aurellia; Sasongko, Nugroho Adi; Apriliyanto, Yusuf Bramastya; Hasibuan, Anggi Khairina Hanum; Ananda, Dea Dwi
Indonesian Journal of Chemical Studies Vol. 4 No. 1 (2025): Indones. J. Chem. Stud., June 2025
Publisher : Indonesian Scholar Society

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55749/ijcs.v4i1.53

Abstract

Radar is a detection and tracking technology commonly applied to monitor environmental conditions. Its ever-growing capabilities pose a serious challenge to military operations because they increase the risk of being detected by the enemy. On the other hand, unmanned aircraft (drones) are increasingly widespread in gathering information. However, the effectiveness of this technology can be reduced due to exposure to radar waves that allow detection. Therefore, developing coating materials that can absorb radar waves is an urgent need to increase the effectiveness of military equipment. The composites developed were derived from chitosan obtained from crustacean waste, hydroxyapatite from eggshell waste, and the rare earth metal cerium obtained from Lapindo Mud. Composites containing cerium metal (Ce) have higher radar signal absorption capabilities than samples without Ce, as evidenced by VNA measurements showing increased absorbance in the 100 MHz - 8.5 GHz frequency range. SEM tests indicate that cerium particles increase the density and homogeneity of the pore structure, with a size range of 17–24 µm. FTIR characterization revealed that Ce was physically bound to the chitosan-HAp composite. Mechanically, the composite with Ce had a maximum tensile stress of 9.512 MPa and a strain of 9.512%, while without the addition of Ce, a stress of 9.529 MPa and a strain of 25.512% was obtained. These findings indicate that integrating rare earth metals in chitosan-HAp composites can improve the material's capability to absorb radar waves, thus having broad prospects for applications in defence technology.
Copolymerization of Tapioca Starch Waste through Grafting of Acrylic Acid Monomer with Cerium(IV) Initiator as Super Absorbent Polymer (SAP) Candidate Kurniadi, Tedi; Prasojo, Agus Eko; Putri, Riyanti; Nurwanto; Hartono, Rudi; Atmadi
Indonesian Journal of Chemical Studies Vol. 4 No. 2 (2025): Indones. J. Chem. Stud. December 2025
Publisher : Indonesian Scholar Society

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55749/ijcs.v4i2.81

Abstract

Indonesia, one of the world's largest tapioca starch producers, generates abundant cassava starch waste (onggok) that remains underutilized. This study aimed to enhance the value of onggok by synthesizing a superabsorbent polymer (SAP) through graft copolymerization using acrylic acid monomer and cerium(IV) initiator. Grafting was optimized by varying monomer concentrations (10–40% w/w) while maintaining the initiator concentration at 1.70% (w/w) and a reaction temperature of 53 °C. The optimal grafting occurred at 20% monomer concentration, yielding a grafting percentage of 14.83% and a monomer conversion of 74.15%. FTIR analysis showed increased absorbance ratios of –OH to C=O functional groups, confirming successful grafting. SEM images revealed a transformation from granular to porous structures, while DSC analysis demonstrated a shift in gelatinization temperature from 45.91 °C (raw onggok) to 46.69 °C (grafted), and retrogradation temperature from 140.67 °C to 141.67 °C. The water absorption capacity of the grafted copolymer reached 4.2450 g/g (5.20 g total), nearly double that of raw onggok (2.2716 g/g or 3.20 g), confirming its effectiveness as a SAP material.
Co-Authors Ananda, Dea Dwi ANGGI KHAIRINA HANUM HASIBUAN Anitasari, Reza Anty, Mentari Zikri Arief Budi Santiko, Arief Budi ARIYANTI, DITA Atmadi Aulia, Desi Rahma Yanti Bolilanga, Patricya Inggrid Wilhelmina Budiman, Anggito Elva Stiawan Fahri, Mirad Gita, Mutiara Hartono, Rudi Hasnowo, Lutfi Aditya Julianingrum, Shavira Triana Kurniadi, Tedi Lazuardy, Ardyan Mayori, Ersha Nugroho Sasongko Jati, Nugroho Sasongko Nurrosyid, Naufan Nurwanto Putra, M. Sulthon Nurharmansyah Putri, Riyanti Rahmat Basuki Salsabila, Fidela Aurellia Septaningsih, Dewi Sijabat, Windy Nelasari Siregar, Fuad Idris Tiarani, Sekar Ilma Wardha, Sophia Nafisa Wiana, Regita Andriani Yunita, Amalia Yusuf Bramastya Apriliyanto