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All Journal POSITRON Electrician : Jurnal Rekayasa dan Teknologi Elektro
Maharsi, Retno
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Control & Systems Engineering Electrical & Electronics Engineering Energy Engineering Physics

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Electrochemically Exfoliated Graphite/Cu/Cu2O Composites and Their Photocatalytic Activity Destiarti, Lia; Abdillah, Oktaviardi Bityasmawan; Maharsi, Retno; Floweri, Octia; Iskandar, Ferry
POSITRON Vol 10, No 1 (2020): Vol. 10 No. 1 Edition
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam, Univetsitas Tanjungpura

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (537.126 KB) | DOI: 10.26418/positron.v10i1.37260

Abstract

In this work, the photocatalytic performance of electrochemically exfoliated graphite (EG) with low copper addition (≤ 5 wt.%) was studied. Composites of EG/Cu/Cu2O were successfully prepared by microwave-assisted in situ reduction method. FTIR spectra of the samples showed that the main functional groups of graphite were detected in the samples. XRD characterization further proved the presence of EG, Cu, and Cu2O in the samples. The higher proportion of Cu2O presented in the samples prepared with a higher amount of Cu2+. SEM analysis showed that Cu2O/Cu particles were homogeneously deposited on the surface of EG. The composites of EG, Cu, and Cu2O with a varied amount of Cu (1 and 5 wt. %) in EG / Cu2+ mixture were examined as photocatalyst in the degradation process of Rhodamine B (RhB). The photocatalytic degradation of RhB was analysed by observing its decolorization within a set time of irradiation. UV-Vis analysis revealed that the degradation of RhB in EG/Cu/Cu2O A and B for 105 minutes was 26 and 35 %, respectively. The result demonstrates that the sample with a larger amount of Cu2O (sample B, Cu 5 wt.%) shows higher photocatalytic activity in the degradation of RhB.
Studi Perencanaan Pembangkit Listrik Hibrid di Kelompok Ternak Sukamaju II Gani, Ferizandi Qauzar; Mustaqim, Amrina; Maharsi, Retno; Iqbal Damara, Muhammad
Electrician : Jurnal Rekayasa dan Teknologi Elektro Vol. 19 No. 2 (2025)
Publisher : Department of Electrical Engineering, Faculty of Engineering, Universitas Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/elc.v19n2.2797

Abstract

This study focuses on the generation of energy from biogas and solar power into electricity in Purwodadi Dalam Village. It focuses on assessing both technical and economic feasibility, alongside the environmental benefits of reducing greenhouse gas emissions. The findings indicate that hybrid power plants have the capability to generate 76.365 kWh/year, 132.812 kWh/year, and 17.062 kWh/year, utilizing readily available raw materials. From an economic perspective, the project is projected to achieve net present values of Rp.327.085.000 and Rp.726.808.000, a benefit-cost ratio of 1.99 and 3.21, and investment payback periods of 6 years 9 months and 3 years 15 days. Additionally, the project offers a significant reduction in emissions, with potential reductions of 618,894 tCO2/year, 618,894 tCO2/year, and 18.30 tCO2/year. These results suggest that the development of this renewable energy project is both technically and economically viable
Simulasi Performa Mekanik Jarum Mikro Berbahan Tembaga Menggunakan Perangkat Lunak ANSYS Maharsi, Retno; Rohmah, Aidah; Widyawasih, Tata; Putra, Damianus Dinata; Milesa, Sabrina; Nugroho, Doni Bowo; Mustaqim, Amrina
Electrician : Jurnal Rekayasa dan Teknologi Elektro Vol. 19 No. 3 (2025)
Publisher : Department of Electrical Engineering, Faculty of Engineering, Universitas Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/elc.v19n3.2858

Abstract

Microneedles are a minimally invasive transdermal technology that has been widely explored in biomedical applications. Copper (Cu) is a promising material for microneedles due to its favorable mechanical properties and inherent antimicrobial effects. However, numerical studies on the structural performance of copper microneedles remain limited. This study aims to evaluate the mechanical response of solid copper microneedles using finite element analysis (FEA) in ANSYS Workbench. A 3D conical microneedle model with a height of 1000 µm was subjected to external pressures ranging from 400 to 1000 MPa. Four key parameters—total deformation, equivalent stress, maximum principal stress, and structural error—were assessed under two mesh densities (coarse and fine). Simulation results indicate that the fine mesh yields more accurate and stable stress and deformation distributions compared to the coarse mesh. Additionally, the fine mesh better captures peak stress concentrations, which are critical for evaluating microstructural failure. These findings underscore the importance of mesh selection in numerical simulations and provide a foundation for the preliminary design of copper-based microneedles for medical applications.
Co-Authors Abdillah, Oktaviardi Bityasmawan Amrina Mustaqim Destiarti, Lia Doni Bowo Nugroho Ferizandi Qauzar Gani Ferry Iskandar Floweri, Octia Iqbal Damara, Muhammad Milesa, Sabrina Putra, Damianus Dinata Rohmah, Aidah Widyawasih, Tata