Newton-Maxwell Journal of Physics

Desain dan Implementasi Alat Pengisi Bahan Bakar Otomatis Pada Kapal Kayu 6 GT

Fri, 24 Oct 2025 00:00:00 +0000

To reduce pollution caused by fuel spills during the refueling process, this research designs and implements an automatic fuel filling device on a wooden boat with a capacity of 6 GT. This system consists of the JSN-SR04T ultrasonic sensor unit, an automatic pump, Neopixel-based LED visual indicators, and a microcontroller as the control center. This tool is designed to automate the fuel transfer process from the dock tank to the ship's tank without the need for manual intervention, thereby increasing operational efficiency and safety. Laboratory tests show that the system has high accuracy, with a Root Mean Square Error (RMSE) value of 0.30 cm, equivalent to an accuracy level of 99.39% in measuring the fuel surface height. In field tests on the Sungai Ungar–Batam route, this device was able to fill 75.76 liters of fuel in 9 minutes and 29.15 liters in 3 minutes automatically. The system is capable of detecting fuel levels, activating the pump when needed, and providing real-time visual notifications. The system's performance is affected by turbulence in the tank when the ship is moving, which reduces the stability of the sensor readings. Therefore, the use of sensors that are more resistant to dynamic conditions and the expansion of testing on larger capacity ships will be the next direction for development.

Identifikasi Kondisi Atmosfer Kejadian Hujan Lebat Jakarta Selatan Berbasis Data Observasi, Satelit, dan Model ERA-5 (Studi Kasus 11 November 2024)

Krisna Dwi Oktabrian, Yahya Darmawan, Nuzula Elfa Rahma, Rizky Franchitika — Fri, 24 Oct 2025 00:00:00 +0000

On November 11, 2024, a heavy rainfall event with a recorded precipitation of 94.6 mm occurred in South Jakarta, leading to flooding in the area. This study aims to analyze the atmospheric factors that contributed to the event and emphasize the importance of integrating satellite data, numerical models, and observational data in understanding extreme weather phenomena. The data used in this study include ERA-5 reanalysis data from ECMWF, satellite imagery from Himawari-9, and observations from automatic rain gauges (ARG). The analysis results indicate that the heavy rainfall was influenced by several key factors, including significant moisture transport from the Indian Ocean, strong low-level convergence, and unstable atmospheric conditions. The convective available potential energy (CAPE) value approached 900 J/kg, and the relative humidity reached 90%, both supporting the development of deep convective clouds. These findings highlight the importance of integrating data from various sources in diagnosing and understanding the mechanisms behind extreme rainfall events in tropical urban regions.

Pengisian Baterai Ion Litium dengan Variasi Arus Menggunakan Modul TP4056 dan TP5100

Septia Refly, Gandhi Rizky Mahendro Putra, Hollanda Arief Kusuma — Fri, 24 Oct 2025 00:00:00 +0000

The charging speed of lithium-ion batteries depends on the applied current, with higher currents resulting in faster charging. However, higher currents can increase the surface temperature, potentially damaging components or causing safety hazards. This study measured the surface temperature of lithium-ion batteries using the DS18B20 sensor. The TP4056 module was used for currents of 880.9 mA, 982.30 mA, and 1134.40 mA, while the TP5100 module was used for a current of 1323.80 mA. Charging at 1328.38 mA required the shortest time, approximately 3-4 hours. Temperature measurements showed no significant increase across the range of 880.0-1328.38 mA. For 982.30 mA, the first and second measurements recorded maximum temperatures of 34.4 °C and 36.2 °C, respectively. In the third measurement at 1328.38 mA, the maximum temperature reached 35.5 °C. Overall, the temperature variations remained below the maximum safe limit for lithium-ion battery charging.

Estimasi Koreksi Relativistik pada Efisiensi Mesin Carnot dalam Kerangka Non-Inersia

Arifin Achmad, Muflihatun, Sulistiyani Hayu Pratiwi — Fri, 24 Oct 2025 00:00:00 +0000

This paper investigates relativistic corrections to the efficiency of Carnot engines in non-inertial frames, focusing on massive objects such as neutron stars and black holes. The results of this study show that, in non-inertial frames, the local temperature and the efficiency of Carnot engines are influenced by rotation and linear acceleration. Using a relativistic approach, it is found that the efficiency correction depends on the acceleration and angular velocity parameters. Simulation results indicate that relativistic corrections become significant under extreme conditions, such as rapidly rotating neutron stars of about 10-4 to 10-3 or in strong gravitational fields around black holes of about O (1). This paper does not examine in detail the mass distribution, magnetic field effects on rotating neutron stars, or quantum effects on black holes. Instead, it focuses on estimating the Tolman temperature correction for non-inertial frames.

Dependence of Crystallinity and Crystallite Size of Hydroxyapatite from Chicken Eggshell on Calcination Time : A Comparative Study on Scherrer Approach

Fri, 24 Oct 2025 00:00:00 +0000

The increasing demand for bone graft materials has driven the development of synthetic alternatives that closely mimic the mineral structure of natural bone and dental tissues. Hydroxyapatite (HAp) is a calcium phosphate material whose crystal structure closely resembles that of bone and dental tissue, making it highly suitable for various biomedical applications. In this study, calcium oxide (CaO) was obtained from calcined chicken eggshells, with calcination durations of 2, 3, and 4 hours, followed by the synthesis of HAp using the hydrothermal method at 160 for 24 hours. X-ray diffraction (XRD) analysis was performed to evaluate the effects of calcination time on crystallinity and crystallite size. The results showed that increasing the calcination time led to higher crystallinity, ranging from 46% to 54%. Crystallite size was estimated using three Scherrer-based methods. The straight-line Scherrer method produced values ranging from 1733.17 to 4621.8 nm, the average Scherrer method from 11.33 to 11.74 nm, and the modified Scherrer method from 8.49 to 9.11 nm. All three methods consistently indicated a decrease in crystallite size with longer calcination durations. These findings demonstrate that prolonged calcination enhances crystallinity and reduce crystallite size, underscoring the critical role of calcination time in shaping structural characteristics of HAp.

Optical Property Enhancement in Cobalt Doped Magnetite Nanoparticles Evaluated with UV Vis Tauc and Urbach

Fri, 24 Oct 2025 00:00:00 +0000

Magnetite (Fe₃O₄) is a spinel-based material that has broad potential in various applications, one of which is for magneto-optics. However, the value of the energy gap obtained from magnetite is too small to be applied. Efforts to improve these characteristics are carried out through transition metal ion doping techniques, one of which is cobalt (Co²⁺) which is known to modify the electronic structure and stabilize the crystal lattice. This study aims to analyze the optical properties of magnetite nanoparticles that have been doped with Co²⁺ through energy gap and Urbach energy calculations. The synthesis of Co_0.125Fe_2.875O₄ was carried out using the coprecipitation method. Furthermore, characterization was carried out using UV–Vis spectroscopy and analyzed the size of the energy gap and Urbach energy. The results showed that cobalt doping (Co_0.125Fe_2.875O₄) produced two indirect energy gap values of 2.07 eV and 3.19 eV and one direct energy gap value of 3.63 eV. Urbach energy analysis revealed a very low E_u value of 0.0073 eV, indicating high crystal regularity and minimal structural defects in the material. This study demonstrated that cobalt doping not only increases the band gap energy of magnetite but also significantly lowers the Urbach energy, resulting in a material with more pronounced optical properties.