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All Journal Jurnal MIPA PHARMACON CHEMISTRY PROGRESS Jurnal Penelitian Fisika dan Aplikasinya (JPFA) Jurnal Ilmiah Arena Tekstil JPPPF (Jurnal Penelitian dan Pengembangan Pendidikan Fisika) INDONESIAN JOURNAL OF APPLIED PHYSICS Informatika Jurnal Abdi Insani Jurnal Fisika dan Terapannya Journal of Student Development Information System (JoSDIS) Jurnal Ilmiah Sains Jurnal Lentera: Penelitian dan Pengabdian Masyarakat
Mahendra Kusuma Nugraha
Physics Department, Faculty Of Mathematics And Natural Sciences, Sam Ratulangi University
Agriculture, Biological Sciences & Forestry Astronomy Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Civil Engineering, Building, Construction & Architecture Computer Science & IT Control & Systems Engineering Decision Sciences, Operations Research & Management Earth & Planetary Sciences Economics, Econometrics & Finance Education Energy Engineering Environmental Science Health Professions Industrial & Manufacturing Engineering Languange, Linguistic, Communication & Media Law, Crime, Criminology & Criminal Justice Library & Information Science Materials Science & Nanotechnology Mathematics Medicine & Pharmacology Physics Public Health Other

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Analisis Metode Elektrokoagulasi Dalam Menurunkan Kesadahan Air Sumur Dengan Variasi Jenis Elektroda Jumriadi; Bakti, Andi Ikhtiar; Nugraha, Mahendra Kusuma
CHEMISTRY PROGRESS Vol. 16 No. 1 (2023)
Publisher : Sam Ratulangi University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.35799/cp.16.1.2023.48369

Abstract

Ada berbagai metode untuk menurunkan kesadahan air, masing-masing dengan kelebihan dan kekurangannya. Metode elektrokoagulasi karena kesederhanaannya telah banyak mendapatkan perhatian untuk digunakan dalam menghilangkan berbagai ion dan bahan organik. Tujuan dari penelitian ini adalah untuk mengetahui pengaruh jenis elektroda dalam menurunkan kesadahan air sumur serta dapat menentukan nilai tegangan dan arus yang optimum dalam metode elektrokoagulasi. Penelitian ini dilakukan dengan menggunakan beker glass 1 L diletakkan di atas magnetic stirrer dengan kecepatan pengadukan 450 rpm selama 30 menit. Variasi elektroda menggunakan Al-Al, Fe-Fe, dan Cu-Cu. Air sumur bor yang berada di asrama mahasiswa Bidikmisi Universitas Halu Oleo yang digunakan dalam penelitian ini dengan kosentrasi awal untuk CaCO3 adalah 312,36 mg/L dan kosentrasi Ca 96,88 mg/L. penurunan kosentrasi kesadahan yang terbaik dengan menggunakan elektroda Cu-Cu pada tegangan 12 V yakni  9,38 mg/L untuk Ca dan 109,44 mg/L CaCO3, disusul elektroda Fe-Fe dengan penurunan 18,75 mg/L Ca dan 124,49 CaCO3 kemudian elektroda Al-Al dengan penurunan 53,13 mg/L Ca dan 160,51 mg/L CaCO3.   Kata Kunci: Elektrokoagulasi, kesadahan air sumur, jenis elektroda
Hydrogeophysical Characterization of Volcanic Aquifers Using Integrated Resistivity and Induced Polarization in Mount Tumpa, Manado As'ari As'ari; Seni Herlina J. Tongkukut; Mahendra Kusuma Nugraha
Jurnal Ilmiah Sains Volume 26 Issue 1, April 2026
Publisher : Sam Ratulangi University, Manado, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.35799/jis.v26i1.65145

Abstract

This study investigates the aquifer system in the Mount Tumpa area, North Sulawesi, Indonesia, using integrated electrical resistivity and induced polarization (IP) methods. Data were acquired with a dipole–dipole array, enabling high lateral resolution of subsurface heterogeneity. Resistivity inversion was used to delineate aquifer geometry, while IP data were analyzed to identify zones of enhanced electrochemical polarization related to lithological and mineralogical variations. Aquifer zones are characterized by low resistivity values (< 9.17 Ωm). On Line 1, an aquifer is identified at 100–130 m and depths of 15–25 m; on Line 2, at 215–230 m and depths of 10–20 m. On Line 3, three distinct aquifer units are resolved: (1) 150–175 m at depths ≥ 75 m, (2) 220–235 m at 30–40 m, and (3) 285–305 m at 35–45 m. These findings indicate a multi-layered groundwater system with variable depth distribution. Chargeability responses are high on Lines 1 and 3 and moderate on Line 2, suggesting the presence of polarizable materials such as volcanic clay, iron oxides, and organic-rich layers. These materials may influence groundwater geochemical behavior through adsorption and redox processes; however, IP responses do not directly indicate groundwater quality in the absence of hydrochemical data. The subsurface is interpreted as a layered volcanic aquifer system, where groundwater is primarily hosted in permeable lapilli and volcanic ash deposits overlying compact lava, with additional storage in fractured lava zones. The identified aquifers are interpreted as shallow to intermediate systems based on geophysical evidence, although further hydrogeological validation is required. Keywords: resistivity method; induced polarization; chargeability; Mount Tumpa; aquifer characterization
Prediksi Biaya Pemakaian Listrik Dengan Metode Logika Fuzzy Mamdani Wahyuni Fithratul Zalmi; David Pang; Mahendra Kusuma Nurgraha
Jurnal Informatika Vol 12, No 3 (2024): INFORMATIKA
Publisher : Fakultas Sains & Teknologi, Universitas Labuhanbatu

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.36987/informatika.v12i3.6337

Abstract

Understanding the electricity tariff class is needed to predict how much usage costs or electricity bills that must be incurred by customers. Each power capacity has a different basic electricity tariff based on the class, household, business and industry. Fuzzy logic can solve problems with imprecise and heuristic data by producing accurate conclusions. The conclusion obtained from the Fuzzy Logic results is expected to be a consideration for customers in predicting electricity usage costs based on electricity tariff groups and customer electrical power capacity. The proposed research uses the Mamdani Fuzzy Logic Method, the use of this method aims to facilitate customers in predicting the cost of electricity usage based on the electricity tariff class and the customer's electric power capacity. The output of this research is the result of predicting the cost of electricity usage based on the power group in residential homes. The higher the tariff group, the number of kWh, electronic goods, and usage time, the higher the predicted energy consumption used. The results obtained from adjusting the fuzzy input antecedents and fuzzy values, namely [900;850;30;20], then for Type_Tariff Power 900, Total_KWh 850, Electronics 30, and Time_Use 20 is 986. Then the cost that must be incurred in the example case above is 1,333,072 rupiah.
Visual Analysis on Photoacoustic Emission Images of Synthetic Dye Contrast Agents inside a Simple Closed-Surface Phantom Mahendra Kusuma Nugraha; Ernawatil Gani; Mitrayana Mitrayana
INDONESIAN JOURNAL OF APPLIED PHYSICS Vol 15, No 1 (2025): April
Publisher : Department of Physics, Sebelas Maret University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.13057/ijap.v15i1.77839

Abstract

A straightforward photoacoustic microscopy imaging system utilizing a laser diode emitting photons at wavelength of 450 nanometers was employed for visualizing contrast-enhanced phantom objects. These phantoms consist of polypropylene tubes with a diameter of 0.3 cm, infused with three types of dye solutions: methylene blue, methyl orange, and methyl red, at varying concentrations of 10 ppm, 25 ppm, 50 ppm, and 100 ppm. In total, twelve phantom objects were imaged, each positioned over a 1x1 cm imaging area constructed from composite galvalume plates. A condenser microphone with audiosonic frequency response was employed as the photoacoustic detector, capturing ones generated by the objects. These emissions were subsequently processed and transformed into two-dimensional polychromatic images. Three primary aspects govern the visual characteristics of each acquired image: (i) the visible light absorption capacity at 450 nanometers for each type of dye; (ii) the concentration of soluble dye molecules; and (iii) the geometry and shape of the polypropylene tube functioning as the closed-surface phantom. It was discovered that utilizing polypropylene tubes as the closed-surface phantom can hinder the propagation of photoacoustic emissions generated by the solution, leading to significantly lower measured photoacoustic intensity than expected. When combined with the intrinsic properties of the contrast agents used, this key factor ultimately shapes the image features obtained from this experiment.
Performance Characterization of 450 nm Visible Light Based Photoacoustic Imaging for Phantom Imaging of Synthetic Dye Contrast Agents Mahendra Kusuma Nugraha; Moh. Ali Joko Wasono; Mitrayana Mitrayana
INDONESIAN JOURNAL OF APPLIED PHYSICS Vol 12, No 1 (2022): April
Publisher : Department of Physics, Sebelas Maret University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.13057/ijap.v12i1.49179

Abstract

Performance characterization of 450 nm visible light photoacoustic imaging has been carried out through phantom imaging of methylene blue (MB), methyl orange (MO), and methyl red (MR) dye solutions. The phantom was made of a nylon tube with a diameter of 5.0 mm (outside) and 4.6 mm (inside) having a height of 2.0 mm along with a 6×6 cm black galvanized aluminum plate as the background medium. The nylon tube was filled with each type of solution with varying molecular concentrations of 10, 25, 50 and 100 ppm. Twelve (12) phantom objects were imaged in an area of 10×10 cm. The visible absorption peak known from UV-Visible spectroscopy for each type of solution is at 664 nm (methylene blue), 465 nm (methyl orange), and 522 nm (methyl red). It was also known that the amplitude of PA emissions would increase proportionally to the concentration of dye molecules. Overall, methyl orange solutions had the highest photoacoustic emission amplitude distribution. The analysis showed that the ratio of inner diameter (ID) and wall thickness (WT) between the MB and MO phantom images to the original object were 1:0.83 and 1:0.74 (ID) and 1:3 and 1:1.5 (WT), respectively. On the other hand, the ratio of the outer diameter (OD) of the MR phantom image to the original object is 1:1.28. 
Dual Estimation Approach to Falling-Ball Viscometry Using Terminal and Transient Velocity Data from Video Tracking Mahendra Kusuma Nugraha; Ernawatil Gani; Berton Maruli Siahaan
Jurnal Penelitian & Pengembangan Pendidikan Fisika Vol. 12 No. 1 (2026): JPPPF (Jurnal Penelitian dan Pengembangan Pendidikan Fisika), Volume 12 Issue
Publisher : Program Studi Pendidikan Fisika Universitas Negeri Jakarta, LPPM Universitas Negeri Jakarta, HFI Jakarta, HFI

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/1.12108

Abstract

In this study, a motion-tracking analysis method was applied to a viscometry system to measure free-fall velocity and determine the viscosity of a fluid. Experiments were conducted by dropping a marble into a tube containing the test liquid with known density, then recording its free-fall motion with a digital camera at 30 frames per second and analysing the data with Tracker software. From the calculated terminal velocity analysis across two trials ((7.46 ± 0.01) × 10-4 m/s and (8.64 ± 0.01) × 10-4 m/s), the viscosity values obtained were 3.0 Pa·s and 2.59 Pa·s, respectively, which are well within the acceptable range. An alternative approach using exponential curve fitting to analyse the transient phase did not yield results as accurate or comparable to the previous, because the data showed a linear relationship between position and time. In two consecutive trials, the viscosity values calculated using this method are 2.81 × 10-2 Pa·s and 3.02 × 10-2 Pa·s. This condition was likely caused by the camera's limited frame rate, which was insufficient to capture the continuous, subtle changes in downward velocity during the first phase of free-fall motion, which occurred over a very short period. Therefore, in a basic, simple yet standard experimental setup, viscosity can be reliably calculated only by measuring the terminal velocity in accordance with Stokes' law.
Co-Authors Afrioni Roma Rio Alfamega Pinasang Antasionasti, Irma As'ari As'ari Bakti, Andi Ikhtiar Berton Maruli Siahaan David Pang Ernawatil Gani Ernawatil Gani, Ernawatil Fithratul Zalmi, Wahyuni Freddy Haryanto Gayatri Citraningtyas Hariyanto, Yuanita Amalia Imam Jayanto Jayanto, Imam Jayawarsa, A.A. Ketut Jumriadi Mitrayana - Mitrayana Mitrayana Moh Ali Joko Wasono Pandji Triadyaksa Rendy Syahputra Seni Herlina J. Tongkukut Sri Sudewi, Sri Sutrisna, Agung Zaenul Muhlisin