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INDONESIA
INDONESIAN JOURNAL OF APPLIED PHYSICS
Published by Universitas Sebelas Maret
ISSN : 20890133     EISSN : 24776416     DOI : -
Core Subject : Science,
Astronomy Energy Materials Science & Nanotechnology Physics
Indonesia Journal of Apllied Physics provides rapid publication of short reports and important research in all fields of physics. Indonesia Journal of Apllied Physics publishes articles that are of significance in their respective fields whilst also contributing to the disclipline of physics as a whole. Articles should be submitted to the Editorial Office of Indonesia Journal of Apllied Physics through this site. Further information on submission is also available at this site
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Articles 351 Documents
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Characterization and Cross-Sectional Modeling of the Newly Identified Rawup Fault Based on Relocated Hypocenters and Focal Mechanism in South Sulawesi Kevin Hanyu Clinton Wulur; Joshua Purba; Ramadhan Priadi
INDONESIAN JOURNAL OF APPLIED PHYSICS Vol 15, No 2 (2025): October
Publisher : Department of Physics, Sebelas Maret University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.13057/ijap.v15i2.104787

Abstract

This study presents an integrated seismotectonic analysis combining earthquake hypocenter relocation and P-wave polarity–based focal mechanism modeling to investigate the microseismic cluster in the Maros–Pangkep region, South Sulawesi. Using seismic data recorded by the BMKG network between 2019 and 2024, a total of 191 events were successfully relocated through the double-difference (HypoDD) algorithm, achieving a significant reduction in RMS residuals. The relocated hypocenters delineate a coherent northwest–southeast–trending fault plane with a strike of approximately 260° and a dip of 7–9°, consistent with a dextral strike-slip mechanism exhibiting minor oblique components. Integration with polarity-derived focal mechanisms confirms a consistent stress orientation compatible with regional compression along the Walanae Fault System. This alignment suggests the presence of a previously unmapped active structure, herein referred to as the Rawup Fault, accommodating local stress redistribution between carbonate and volcanic–clastic units. The findings advance the understanding of active deformation in low-seismicity, karst-dominated terrains and demonstrate the value of combining relocation and focal mechanism analyses for detecting hidden faults. These results provide new insights into the tectonic evolution and seismic hazard potential of the Maros-Pangkep.
An Implementation of XGBoost and Random Forest Algorithm to Estimate Effective Porosity and Permeability on Well log data at Fajar Field, South Sumatera Basin, Indonesia Ilham Diaz Rahmat Nugroho; Muhammad Destrayuda Trisna; Sudarmaji Saroji
INDONESIAN JOURNAL OF APPLIED PHYSICS Vol 14, No 2 (2024): October
Publisher : Department of Physics, Sebelas Maret University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.13057/ijap.v14i2.82901

Abstract

New approaches and methodologies have been developed to petrophysical analysis from well logs data using machine learning. Through this method, a machine learning algorithm is applied to predict the accuracy of the model on effective porosity (∅e) and permeability (K) which implemented using Random Forest and Xtreme Gradient Boosting (XGBoost) algorithm. The dataset used is obtained from well logs data that have been calculated petrophysical analysis. This study proposes the algorithm which is known to be effective in providing accurate predictions in a short time in estimating effective porosity and permeability. The results of the prediction model is optimized by GridSearchCV (GS), validated by the k-fold cross-validation, and evaluated using R2 score and Root Mean Square Error (RMSE). Model is applied to 5 research wells in Fajar Field of south Sumatra Basin, Indonesia with 4 variations of well training and well testing data split. The best evaluation results obtained with evaluation metrics were up to 0.90 (R2 score) and 0.01 (RMSE) for effective porosity and permeability by Random Forest, while evaluation metrics are 0.90 (R2 score) and under 0.68 (RMSE) for effective porosity and permeability by XGBoost. There is no decrease in accuracy until the last variation so that it can be concluded that these algorithm models can effectively estimate reservoir porosity and permeability in the field and contributed an alternative for the problem of many incomplete and dissimilar well logs data.
Literature Review−Effect of Additives and Post-Treatments on Corrosion Resistance and Mechanical Properties of Plasma Electrolytic Oxidation Products in Magnesium and Titanium Sri Rahmadani; Anawati Anawati
INDONESIAN JOURNAL OF APPLIED PHYSICS Vol 14, No 2 (2024): October
Publisher : Department of Physics, Sebelas Maret University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.13057/ijap.v14i2.73616

Abstract

Plasma Electrolytic Oxidation (PEO) is a method of converting metal surfaces into an oxide layer with the help of plasma to improve the surface mechanical properties and corrosion resistance of metals. A PEO layer of about 10-50 μm is obtained quickly from 1 second-10 minutes at a voltage range of 150-500 V with AC or DC mode. Characteristics of the outer layer of PEO have pores and cracks, while the inner layer is relatively denser. Cracks and pores reduce the corrosion resistance and mechanical properties of the coating. In this study, a literature search was carried out on the effect of adding additives and post-treatment on the characteristics of PEO coatings grown on magnesium (Mg) and titanium (Ti) metals for biomedical applications. Mg and Ti metals have opposite chemical properties; Mg is a reactive metal, while Ti is an inert metal. Comparing the behavior of the PEO process and the coating produced by the two different metals is absorbing and necessary to understand the fundamentals of the PEO process. The results of a literature search show that the addition of additives increases the growth rate of the coating so that the coating is thicker and more wear resistant. The hardness of the coating also increases due to the additive particles trapped in the oxide layer filling the micro pores so that the surface becomes denser and more homogeneous. Therefore, corrosion resistance also increases, as indicated by a decrease in corrosion current as measured by the polarization test and an increase in the impedance modulus as measured by the electrochemical impedance test (EIS). The post-alkali treatment allows for increased surface bioactivity, as indicated by the rise in the Ca/P ratio after immersion in a physiological solution.
Lung Cancer Detection Using a Modified Convolutional Neural Network (CNN) Cari Cari; Mohtar Yunianto; Aisyah Ajibah Rahmah
INDONESIAN JOURNAL OF APPLIED PHYSICS Vol 14, No 1 (2024): April
Publisher : Department of Physics, Sebelas Maret University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.13057/ijap.v14i1.77032

Abstract

Image processing is used to classify lung images with malignant or normal nodules. The Convolutional Neural Network (CNN) method is often used to classify images. This study uses a modified CNN architecture with various layers, filters, batch size, dropout, and epoch values. Variations were made to determine the best accuracy value and reduce the overfitting value of the proposed CNN architecture. This study implements the method using the Keras library with the Python programming language. The data is in the form of CT-Scan images of lung cancer and normal lungs. The results of several experiments from the proposed model produce an accuracy value of 95% using three layers, 128 filters on the first layer, 256 on the second layer, and 512 filters on the third layer, then with 32 batch sizes, 0.5 dropout.
Boltzmann-Gibbs Entropy to measure Fluctuation of Stock Index Dwi Satya Palupi
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.v15i1.93909

Abstract

The disorder of a physical system can be measured based on the entropy of the system. The greater the entropy value of a system, the more disorder the system increases. In Physics, the disorder of system is measured by Boltzmann-Gibbs Entropy. Boltzmann-Gibbs entropy relates the disorder of a system to the probability distribution of the system's states. The Boltzmann-Gibbs entropy can be extended to more general systems to become the Shanon entropy widely used in information theory. In this research, Boltzmann-Gibbs entropy is used to measure stock market disorder or the fluctuation of stock price. The fluctuation in the stock market are more focused on disorder movements, therefore Boltzman Gibbs entropy is developed into time-dependent entropy using a sliding window technique. The samples in this study were stock indices in Germany (GDAXI), China (HIS), Japan (Nikkei), the United States (Dow-Jones), and Indonesia (IDX). The calculation results show an increase in Boltzman-Gibbs entropy when the economic crisis begins. Entropy decreases when the crisis begins to subside towards a more stable.
Fabrication of Cerium Oxide-Graphene Oxide Nanocomposite using Ultrasound-Assisted Precipitation Method Iis Nurhasanah; Arvia Arvia; Nor Basid Adiwibawa Prasetya; Ahmad Jauhari
INDONESIAN JOURNAL OF APPLIED PHYSICS Vol 14, No 2 (2024): October
Publisher : Department of Physics, Sebelas Maret University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.13057/ijap.v14i2.81259

Abstract

The cerium oxide-graphene oxide nanocomposite was fabricated by ultrasound-assisted precipitation method and characterized using Fourier transform infrared, UV-Vis spectroscopy, X-ray diffractometer, and transmission electron microscope. The Fourier transform infrared spectra displayed the vibrations of O-H, C=C, and C-H indicating the interaction between cerium oxide and graphene oxide. The broad absorption of around 300 nm is ascribed to the superposition of cerium oxide and graphene oxide absorption peaks. X-ray diffraction pattern analysis suggests the creation of graphene oxide nanosheets with an interlayer spacing of 0.821 nm.  The transmission electron microscope image showed that the cerium oxide nanoparticles dispersed on the graphene oxide nanosheet.  These findings exhibit the useful ultrasound-assisted precipitation method for fabricating cerium oxide-graphene oxide nanocomposite.
Sea Wave Height Monitoring Prototype as an Early Warning System for Tidal Flood Disaster Samsul Muhayadi; I Wayan Sudiarta; Eko Pradjoko
INDONESIAN JOURNAL OF APPLIED PHYSICS Vol 15, No 2 (2025): October
Publisher : Department of Physics, Sebelas Maret University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.13057/ijap.v15i2.107543

Abstract

Indonesia is an archipelagic country located between the Indian Ocean to the south and the Pacific Ocean to the north. As a consequence of this, during the rainy and transitional seasons, extreme weather occurs, especially in the southern coastal areas. According to data from the National Disaster Management Agency, in the last six years, more than 200 tidal waves and abrasion have hit the coastal areas of Indonesia. These conditions can lead to various disasters, particularly tidal flooding. Therefore, the development and design a wave height monitoring device as an early warning system for tidal flooding is necessary. This device is expected to play a vital role in disaster mitigation, because it can provide the information about the potential for tidal flooding based on the changes in wave height. The design of this device uses the LPD3806 encoder as a sensor and the nRF24L01 to send information to the monitoring station. Furthermore, running tests has been conducted and based on the results of the maximum distance test, information delivery can reach 800 meters in an open area with a maximum delay of 2 seconds. For sensor accuracy, a value of  99.7% was obtained, indicating the sensor has a small measurement error rate. On top of that, during field tests, the device demonstrated durability under bad weather, with no loss of data sent. This shows that this device can operate reliably under extreme weather environments.
Using Decision Tree With First and Second-Order Statistical Feature Extraction for Classification of Lung Cancer Mohtar Yunianto; Rizka Dewi Meilina; Esti Suryani
INDONESIAN JOURNAL OF APPLIED PHYSICS Vol 14, No 2 (2024): October
Publisher : Department of Physics, Sebelas Maret University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.13057/ijap.v14i2.87676

Abstract

The classification of CT-Scan images on images with lung cancer and normal lung has been done by improving the image quality of the median and Gabor filters, extraction of first and second-order statistical features, and decision tree classification. The data used comes from LIDC-IDRI as much as 100 training data and 40 test data. The median filter removes noise without removing edges in the image. A Gabor filter is used to facilitate texture analysis on the image. At the feature extraction stage, statistical variations of the first order, second order statistics and the merging of first and second-order statistics. The best results obtained at the testing stage are program designs with variations of feature extraction combining first and second-order statistics. The level of accuracy obtained is 97.5%, with a sensitivity of 100% and a specificity of 95%.
Thermo-Fluid Dynamics of PLA Deposition in Fused Filament Fabrication 3D Printing: A Numerical Study Zaki Saptari Saldi; Purba Purnama; Nurmalia Nurmalia; Salman Alfarisi; Muhammad Arifin; Ammar Munadi Suweco
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.v15i1.87634

Abstract

Prototyping plays an important role in product design and has recently gained benefit from the rising popularity of 3D printing. It is to be expected that 3D printing will accommodate more materials, which need to be tailored to specific design requirements. Insights into heat transfer and fluid flows (thermo-fluid dynamics) in the printing process is thus essential to obtain favorable process parameters that can lead to high quality prints. In this work, polylactic acid (PLA) melt in Fused Filament Fabrication (FFF) 3D printing was numerically studied through Computational Fluid Dynamics (CFD) simulations, with a focus on the thermo-fluid dynamics of the strand deposition of the filament melt on the printer platform. The study was carried out by evaluating 6 printing cases, with a variation of 2 key process parameters, i.e., printing speed (30 and 45 mm/s) and platform temperature (310, 320, and 340 K). The simulation results showed that the free surface in the tip region of the strand has the most tendency to adhere to the printing platform heated at 340 K with the printing speed of 45 mm/s, as compared with other cases. This was affected by the lower dynamic viscosity in the region, relative to other cases, resulting from the high platform temperature and shear rate generated by the high printing speed.
Simulation of Boron Dose and Irradiation Time in Lung Cancer Treatment with Boron Neutron Capture Therapy (BNCT) Using MCNP-6 Nita Handayani; Kevin Kautsar Soelistiyono; Fajar Arianto
INDONESIAN JOURNAL OF APPLIED PHYSICS Vol 14, No 1 (2024): April
Publisher : Department of Physics, Sebelas Maret University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.13057/ijap.v14i1.85497

Abstract

Boron Neutron Capture Therapy (BNCT) is a cancer radiation treatment. This approach employs a boron carrier agent in the form of a chemical that is injected into the body and then travels to the cancer cells. In a lung cancer case study, BNCT treatment simulation was carried out using Monte Carlo N Particle (MCNP) software version 6.2. The goal of this study was to determine the most effective boron concentration and irradiation duration in lung cancer therapy utilizing the BNCT method. The geometry based on a phantom model created by Oak Ridge National Laboratory (ORNL). The simulated cancer geometry, which is placed in the right lung's middle lobe. The skin, ribs, and right lung are among the organs at risk. The skin, ribs, and right lung are among the organs at risk. The neutron source for the simulation is the collimator output from the Kartini Nuclear Reactor's thermal column. In this simulation, the variations in boron concentrations were 40 g/g, 45 g/g, 50 g/g, 55 g/g, and 60 g/g of cancer tissue at 5 g/g intervals. The researchers discovered a link between boron injection concentration and irradiation time, with higher boron injection concentrations resulting in shorter irradiation times. The volume of boron injected determines the effective dose absorbed by healthy tissue surrounding cancer cells. The effective boron concentration for lung cancer therapy is 60 g/g, with deterministic cell killing in the rib marrow and right lung. When utilizing a boron concentration of 60 g/g, the irradiation time is 20.4 minutes. Boron concentrations of 60 g/g are projected to create an effective irradiation time for BNCT-based lung cancer therapy based on the ALARA principle due to their shorter duration when compared to other concentration variations.

Page 29 of 36 | Total Record : 351

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