Jurnal Ilmu Fisika (JIF)
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Ionospheric Irregularities Related to Scintillation During Geomagnetic Storm in March, April, 2023 Over Indonesia
Full text linkThis study aims to analyze ionospheric irregularities in plasma structures on scales above 400 meters–several kilometers associated with scintillation using GPS satellite signal observation techniques. This study was conducted in the Indonesian region during the main phase of a strong category geomagnetic storm on March 23-24 and April 23-24, 2023 using Total Electron Content (TEC) and Rate of TEC Index (ROTI), from GPS receiver observations in Manado (1.34˚N-124.82˚E; -7.91˚S), Kupang (10.16˚S-123.67˚E; -19.38˚S), Bandung (6.9˚S- 107.6˚E; 17.5˚S) and Biak (1.0˚S-136.0˚E; 12.18˚S). The results showed that during the geomagnetic storm on March 23-24, plasma irregularities, characterized by irregularities on a scale of more than 400 meters and evidenced by an increase in ROTI, were largely suppressed at all observation sites except Bandung. Likewise, most stations did not show a substantial increase in ROTI values in the subsequent storm on April 23-24, 2023, indicating continued suppression except for the Manado station. Furthermore, changes in TEC variations in response to the March 23-24 storm indicate that stations in Biak and Manado experienced positive storms (increase in TEC), while stations Bandung and Kupang experienced negative storms (decrease in TEC). In contrast, during the storm on April 23–24, 2023, all locations reported positive storms
Binder Influence on Barium Hexaferrite: Comparative Analysis of PVA and Silicone Rubber in Sintered Magnets
No full textThis study explores the impact of binder types—polyvinyl alcohol (PVA) and silicone rubber (SR)—on the physical, magnetic, and mechanical properties of barium hexaferrite (BaFe12O19), synthesized via mechanical alloying and sintered at 1100°C. SEM-EDX confirmed the formation of BaFe12O19 with an average particle size of around 0.7 µm. VSM results showed a saturation magnetization (Ms) of 71.17 emu/g, remanent magnetization (Mr) of 47.8 emu/g, and coercivity (Hc) of 0.33 T. The addition of PVA reduced density (3.13–3.07 g/cm³), increased porosity (17.72%–18.47%), and decreased magnetization (0.93–0.80 mT). In contrast, SR enhanced densification, leading to higher density (3.65–3.57 g/cm³), lower porosity (6.95%–7.51%), and significantly higher hardness (232.9–438.92 HV). SR also improved mechanical strength, while PVA proved more effective in reducing shrinkage and improving magnetization. These results underscore the significant role of binder type and concentration in optimizing the properties of sintered barium hexaferrite, with SR excelling in mechanical strength and PVA in magnetization
Eco-Friendly Solar Refrigerator: Peltier Cooling, Remote Monitoring for Sustainable and Efficient Energy Consumption
Full text linkElectricity is essential for everyday needs, including food preservation through refrigeration. However, access to electricity remains uneven in remote regions due to geographical constraints. Solar energy offers a promising alternative, especially in areas with abundant sunlight, highlighting the need for compact, portable, and eco-friendly cooling system. This study aims to design an eco-friendly cooling system using the Seebeck Effect in Peltier TEC 12706 modules powered by solar energy. The system consists of two Peltier TEC 12706 modules, a 50 Wp solar panel, and a 33 Ah accumulator, with a cooling chamber measuring 26 × 17 × 10 cm. Temperature and humidity were remotely monitored via the Blynk application. Experimental results showed the lowest temperature achieved was 15°C between 08:00 AM and 10:00 AM. In comparison, the most significant temperature drop of 11.7°C occurred between 12:00 PM and 02:00 PM, with an average light intensity of 176,846.15 Lux. Although the system demonstrated cooling performance, the minimum temperature of 15°C does not meet the standard refrigeration temperature of around 0°C. Therefore, the current system is not yet suitable for replacing conventional refrigerators, but it shows potential as an environmentally friendly alternative cooling solution with further development
Effect of Freshwater and Seawater Immersion on Mechanical Properties and Pre-Immersion Magnetic Response of Silicone Rubber–Magnetite Composite Magnets
Full text linkMagnetite (Fe₃O₄) and RTV 48 silicone rubber-based magnetic composites have potential for outdoor applications due to their flexible and tunable magnetic properties. This study investigates the effect of immersion for 14 days in fresh water and seawater on its mechanical, magnetic, and thermal properties. Specimens were made by mixing 70 wt% Fe₃O₄ powder into RTV 48 matrix, then tested for hardness using Shore A durometer, magnetic properties using Vibrating Sample Magnetometer (VSM), and thermal stability using Thermogravimetric Analysis (TGA). Results showed a decrease in surface hardness due to matrix degradation by water penetration. The magnetic properties continued to exhibit soft magnetic characteristics with low coercivity and remanence. TGA analysis revealed changes in thermal degradation patterns, signaling chemical interactions between the material and the wet environment. These findings suggest that exposure to water can affect the long-term performance of Fe₃O₄-RTV 48 composites, making moisture resistance an important aspect for their outdoor applications
Monte Carlo Simulation to Understand the Working Mechanism of The Electrolytes Lithium Hexafloorophosphate and Ethylene Carbonate
Full text linkMonte Carlo (MC) simulations provide a powerful approach to investigate electrolyte–electrode interactions and to optimize battery design. This study aims to determine the entropy and average energy of a lithium salt–ethylene carbonate (EC) system, as these parameters are essential for evaluating the Boltzmann factor. The Boltzmann factor was derived from entropy concepts and the principle of maximum entropy, which involves the Boltzmann constant (k) and the number of accessible states (Ω). Simulations were performed using Lennard–Jones parameters within a canonical ensemble framework to compute entropy and energy for systems with varying atom numbers. Results show that the system entropy for two atom types (200 atoms) was 6.67 × 107 kJ·mol–1·K–1. For three atom types (300 atoms), the equilibrium entropy reached 1.1 × 1010 kJ·mol–1·K–1, and for four atom types (400 atoms), 1.3 × 1013 kJ·mol–1·K–1. When reduced to five atom types with only 300 atoms (to minimize computational cost), the entropy was 2.4 × 108 kJ·mol–1·K–1. The simulations, employing the Metropolis criterion, successfully identified globally stable configurations, providing new insights into entropy-driven behavior in lithium battery electrolytes
Threshold Value of Atmospheric Stability Indices During Thunderstorm Events at Minangkabau International Airport
Full text linkThunderstorms are a significant challenge for aviation operations, especially in tropical regions such as West Sumatra. This study aims to determine threshold values for six atmospheric stability indices—Convective Available Potential Energy (CAPE), K-Index (KI), Lifted Index (LI), Showalter Index (SI), Severe Weather Threat Index (SWEAT), and Total-totals Index (TTI)—to predict thunderstorm events at Minangkabau International Airport (MIA). Radiosonde and daily synoptic reports from 2018–2022 were analyzed using Rawinsonde Observation Programs (RAOB) and Statistical Package for the Social Sciences (SPSS) with a dummy regression approach. The model was validated using a confusion matrix, measuring accuracy, precision, and recall. Results show that the use of locally calibrated thresholds leads to higher and more consistent accuracy, precision, and recall values compared to global benchmarks, due to better adaptation to local weather parameters such as vertical humidity, mid-layer temperature, and wind structure. KI, SI, and TTI showed high sensitivity (recall >88%), while LI and CAPE performed moderately. Monthly variation in index performance was observed, with KI, SI, and TTI dominant in the wet and transition seasons, and SWEAT effective in the dry season when shear-driven convection increases. Thus, locally calibrated indices are recommended for thunderstorm early warning systems in aviation
Optimizing Doppler Ultrasound Parameters: The Study of Insonation Angle, PRF, and Dynamic Range in Blood Flow Assessment
Full text linkDoppler ultrasound is critical in medical diagnostics for evaluating blood flow and detecting vascular conditions. Accurate blood flow velocity measurements depend on insonation angle, Pulse Repetition Frequency (PRF), and dynamic range. This study optimizes these parameters to enhance Doppler ultrasound performance and diagnostic accuracy. A Xario-100 ultrasound machine and the Doppler 403TM flow phantom were used to evaluate the effects of insonation angle, PRF, and dynamic range on measurement accuracy. Insonation angles of 0o and 60o were tested to assess their impact on aliasing and precision. At 0o, significant aliasing occurred, while 90o, aliasing was minimized. PRF settings were adjusted from 14,000 Hz to 17,900 Hz, with higher PRF extending the Nyquist Velocity from 9.8 cm/s to 37.4 cm/s, reducing aliasing and improving high-flow measurement clarity in the dynamic range from 30 dB to 60 dB, with optimal contrast observed at 50 dB. Histogram analysis revealed a balanced pixel intensity distribution at 50 dB, enhancing the Signal-to-Noise Ratio (SNR). The findings demonstrate an insonation angle of 60o, at PRF 17,900 Hz, and a dynamic range of 50 dB optimal Doppler ultrasound performance. Standardizing these parameters can improve diagnostic accuracy, supporting better patient outcomes in clinical practice
Model Kinetik Amyloid-Beta (Aβ) pada Penyakit Alzheimer Menggunakan Metode Euler dan Runge-Kutta Order ke-4
No full textAlzheimer's disease (AD) is a neurological disease that causes decreased brain function. It is known that the accumulation of amyloid-beta (Aβ) plaques in the brain is one of the causes of AD. The accumulation of Aβ plaques in the brain is a dynamic process; it begins with the growth of amyloid-beta monomers (M1). Furthermore, amyloid-beta dimers (M2) and so on, so that this collected into oligomers (O), fibrils (P), and plaques in the brain. This disrupts the communication pathways between nerve cells. In this study, each process of amyloid-beta plaque accumulation is presented with a mathematical model in the form of an ordinary differential equation. Therefore, the coupled ordinary differential equations are given for the entire process of Aβ plaque accumulation. In this study, this coupled model is calculated using numerical methods, such as the Euler and fourth-order Runge-Kutta methods. The Euler methods is simple and efficient, but its accuracy is low and can accumulate errors with larger step sizes. The fourth-order Runge-Kutta methods offers higher accuracy, better numerical stability, and greater control over the accuracy of the solution. These two numerical methods have never been compared for estimating numerical solutions of coupled ordinary differential equations.Penyakit Alzheimer (AD) adalah penyakit neurologis yang mengurangi fungsi otak. Salah satu penyebab AD yang diketahui adalah akumulasi plak amiloid-beta (Aꞵ). Akumulasi plak Aβ di otak menunjukkan proses dinamis yang diawali dengan pertumbuhan monomer. Seiring berjalannya waktu, akumulasi monomer amiloid-beta (M1) akan menjadi oligomer (O), kemudian menjadi fibril (P) dan plak di otak. Hal ini menyebabkan terganggunya jalur komunikasi antar sel saraf. Penumpukan plak amiloid-beta dapat diprediksi dengan model matematika. Dalam penelitian ini model matematika terdiri dari persamaan diferensial biasa berpasangan. Persamaan diferensial biasa yang digabungkan menggambarkan proses akumulasi plak amiloid-beta. Model matematika dihitung menggunakan metode numerik sederhana dan kompleks yaitu metode Euler dan Runge-Kutta orde 4. Simulasi dilakukan menggunakan software MATLAB 2021a selama 100 hari dengan step size 0,01. Hasil simulasi menunjukkan bahwa perhitungan metode Runge-Kutta orde 4 memberikan hasil prediksi yang sama dengan perhitungan menggunakan metode Euler
Identifikasi Keberadaan Batu Apung Berdasarkan Data Georadar dan Data Geolistrik Resistivitas di Kecamatan Ampenan dan Kecamatan Sekarbela, Kota Mataram
No full textRetraction Notice
This article has been retracted at the request of the Editor-in-Chief after reviewing the available evidence and verifying the report received.
The article entitled “Identification of the Presence of Pumice Stone Based on Georadar Data and Geoelectric Resistivity Data in Ampenan District and Sekarbela District, Mataram City” published in Jurnal Ilmu Fisika, Vol. 17 No. 1 (March 2025), was found to have a similarity level of approximately 94% with another article previously published in Lambda: Jurnal Pendidikan MIPA dan Aplikasinya, Vol. 5 No. 1 (April 2025), titled “Kombinasi Metode Georadar dan Geolistrik Resistivitas untuk Mendeteksi Keberadaan Batu Apung di Kota Mataram.”
The research data (Georadar and Geoelectric data) belong to Universitas Mataram and were used without permission from the data owner. Therefore, Arsi et al., as the authors of the article published in Jurnal Ilmu Fisika, are considered to have published the article without authorization from the rightful data owner.
As a result, this article has been formally retracted from the Jurnal Ilmu Fisika archive.Penelitian ini dilakukan untuk mengidentifikasi keberadaan dan distribusi batu apung yang dihasilkan dari letusan Gunung Samalas tahun 1257 M di Kecamatan Ampenan dan Sekarbela, Kota Mataram. Penelitian ini penting karena batu apung merupakan indikator material vulkanik yang memiliki dampak signifikan terhadap karakteristik tanah dan lingkungan setempat. Tujuan dari penelitian ini adalah untuk memetakan distribusi batu apung dan memahami bagaimana material tersebut tersebar di bawah permukaan, terutama di daerah pesisir. Metode yang digunakan adalah georadar dan geolistrik resistivitas, dua metode geofisika yang memungkinkan pengukuran respons listrik bawah permukaan, membantu mendeteksi perubahan resistivitas dan konduktivitas yang mengindikasikan keberadaan material vulkanik seperti batu apung. Hasil menunjukkan bahwa batu apung tersebar merata pada kedalaman 0-9 meter dan bercampur dengan material seperti kerikil, lanau, dan pasir. Pada daerah penelitian menunjukkan bahwa lapisan tanah didominasi oleh pasir, hal ini dapat disebabkan oleh letak geografis daerah tersebut yang berada di wilayah pesisir. Penelitian ini menunjukkan pentingnya penggunaan metode geofisika dalam memetakan distribusi material vulkanik di lapisan dangkal, terutama di kawasan yang terdampak oleh letusan gunung berapi
Analisis Karakteristik Curah Hujan di Pulau Kalimantan dan Hubungannya pada Fase El-Niño dan IOD Positif
No full textThis study aims to analyze the characteristics of rainfall in Kalimantan Island during the ENSO and IOD phases using composite method. This study uses ERA5 reanalysis data for the period 1985-2023. The analysis was carried out using Python in Jupyter Notebook Software to visualize rainfall patterns across four seasons (DJF, MAM, JJA, and SON). The results indicate that El Niño events reduce rainfall during the JJA season, with the largest deficit occurring in the southern region of Kalimantan, where rainfall drops to less than 5 mm per season. Conversely, Positive IOD conditions exacerbate drought, resulting in decreased rainfall in the southern and central parts of the island. The combined effects of El Niño and Positive IOD cause an even more significant decline in rainfall, with the dry season experiencing a substantial reduction compared to normal conditions. This study provides important insights for hydrometeorological risk mitigation in Kalimantan, highlighting the need for adaptive management in response to climate variability.Penelitian ini bertujuan untuk menganalisis karakteristik curah hujan di Pulau Kalimantan pada fase El-Niño dan IOD Positif dengan metode komposit. Data yang digunakan berupa data reanalisis ERA5 periode 1985-2023. Analisis dilakukan dengan menggunakan Python di Jupyter Notebook Software untuk menghasilkan visualisasi pola curah hujan dalam empat musim (DJF, MAM, JJA, dan SON). Hasil penelitian menunjukkan bahwa El-Niño cenderung mengurangi intensitas curah hujan di seluruh wilayah Kalimantan, terutama pada musim JJA. Sementara itu, IOD Positif memperkuat pola kekeringan di Kalimantan bagian selatan dan tengah. Dampak gabungan El Nino dan IOD Positif menyebabkan penurunan curah hujan yang signifikan, terutama di musim kemarau. Studi ini memberikan wawasan penting untuk mitigasi risiko hidrometeorologi di Kalimantan