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BULETIN FISIKA
Published by Universitas Udayana
ISSN : 14114690     EISSN : 25809733     DOI : https://doi.org/10.24843/BF
Core Subject : Health, Science,
Astronomy Energy Materials Science & Nanotechnology Medicine & Pharmacology Physics
Aims and Scope Aims The Journal aims to promote the theory and application in the field of physics and to encourage a vigorous dialogue among scholars and researchers worldwide. It presents original research articles, letters, and review articles, and publishes the latest achievements and developments in physics and related fields. All contributions shall be rigorously refereed and selected based on the quality and originality of the work as well as the breadth of interest to readers. Accepted papers will immediately appear online. The Journal welcomes contributions that the manuscript is written in Indonesian or English. Scope The scope of this journal covers pure and applied physics. The topics include advanced material, optoelectronics, laser applications, biophysics, medical physics, instrumentation, geophysics, environmental physics, and related fields.
Arjuna Subject : Fisika dan Astronomi - Fisika dan Astronomi (Lain-Lain)
Articles 62 Documents
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Characteristics of Ultrasonic Wave Propagation in Reinforced Concrete Based on Variations in Age and Acoustic Impedance Contrast Evin Yudhi Setyono Setyono; Fajar Surya Herlambang
BULETIN FISIKA Vol. 27 No. 2 (2026): BULETIN FISIKA
Publisher : Departement of Physics Faculty of Mathematics and Natural Sciences, and Institute of Research and Community Services Udayana University, Kampus Bukit Jimbaran Badung Bali

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24843/BF.2026.v27.i02.p11

Abstract

This study investigates the characteristics of ultrasonic wave propagation in reinforced concrete at different ages and acoustic impedance contrast. Ultrasonic testing was conducted using UPV James Instrument Mark IV on non-reinforced concrete, plain-reinforced concrete, and deformed-reinforced concrete at ages of 7, 14, 28, 42, and 56 days. The analysis focused on four parameters of wave propagation, which are wave velocity, dynamic elastic modulus, acoustic impedance, and amplitude transmission coefficient. The results show that all three specimens show a similar propagation pattern. A sharp increase in velocity occurs at 7-28 days, indicating intensive hydration and microstructural densification, followed by a more gradual increase at 28-42 days. Reinforced concrete specimens steadily have higher ultrasonic velocities and acoustic impedance values than non-reinforced concrete, indicating the wave propagation path was influenced by steel reinforcement, which has a higher wave velocity and acoustic impedance than concrete. A mild reduction in velocity and acoustic impedance at 42-56 days indicates possible microstructural changes, such as moisture reduction, microcrack initiation, and increased internal scattering. The amplitude transmission coefficient was found to be slightly greater than one (T>1); this can still occur at the interface between two media with different impedances due to the transmission mechanism and normalization of wave amplitude. Steel reinforcement has a much higher acoustic impedance than concrete, so when a wave reaches the concrete-steel interface, the transmitted wave amplitude can be slightly greater than the incident wave amplitude.
Determination of Cardiothoracic Ratio (CTR) and Image Contrast in Chest Radiographs Using Variations in Focus-Film Distance (FFD) Fickry Haikal; Sri Dewi Astuty; Sultan Hamjar; Syamsir Dewang; Bannu Bannu; Arfinna Arfinna; Ayu Hardianti Pratiwi; Ajeng Anggreny Ibrahim
BULETIN FISIKA Vol. 27 No. 2 (2026): BULETIN FISIKA
Publisher : Departement of Physics Faculty of Mathematics and Natural Sciences, and Institute of Research and Community Services Udayana University, Kampus Bukit Jimbaran Badung Bali

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24843/BF.2026.v27.i02.p13

Abstract

Posteroanterior (PA) chest radiography is generally recommended at a focus-to-film distance (FFD) of 180 cm to minimize magnification of the cardiac silhouette, which may affect assessment of cardiomegaly. However, shorter FFDs are sometimes unavoidable because of room constraints or patient-related conditions. This study aimed to evaluate cardiothoracic ratio (CTR) values obtained at different FFDs and assess cardiac image quality using the contrast-to-noise ratio (CNR) to determine the visibility of the right and left cardiac borders. A descriptive observational study with a post-test-only design was conducted using 70 digital PA chest radiographs from male patients aged 17–22 years. The images were divided into seven FFD groups ranging from 120 to 180 cm, with 10 independent samples per group. CTR and CNR were quantitatively measured using ImageJ software. All radiographs demonstrated CTR values below 50% across the investigated FFDs, indicating no radiographic evidence of cardiomegaly. The highest mean CNR values were observed at FFDs of 140 cm (64.458), 150 cm (58.639), and 180 cm (50.758). Statistical analysis revealed no significant differences in CTR (p = 0.515) or CNR (p = 0.141) among the FFD groups. The observed fluctuations in CTR and CNR were likely attributable to inter-individual anatomical variation rather than FFD-related magnification. Differences in chest geometry and tissue attenuation, particularly variations in thoracic thickness and density, may have contributed substantially to the observed measurements. These findings suggest that, within the investigated range, FFD variations from 120 to 180 cm did not significantly affect CTR or CNR in young adult male subjects.
Studi Kelayakan Fitting Tool Farmakokinetik Berbasis Python untuk Estimasi Time-Integrated Activity Coefficient (TIAC) Deka Andini; Choirul Anam; Asep Yoyo Wardaya; Nur Rahmah Hidayati; Bisma Barron Patrianesha
BULETIN FISIKA Vol. 27 No. 2 (2026): BULETIN FISIKA
Publisher : Departement of Physics Faculty of Mathematics and Natural Sciences, and Institute of Research and Community Services Udayana University, Kampus Bukit Jimbaran Badung Bali

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24843/BF.2026.v27.i02.p12

Abstract

Studi ini bertujuan  untuk  studi kelayakan implementasi fitting tool berbasis Python pada estimasi nilai TIAC  di organ ginjal. Data biokinetik ginjal kiri dan kanan  dari 8 pasien yang menjalani terapi [177Lu]Lu-DOTATATE yang digunakan pada studi ini diperoleh dari literatur: PMID33443063. Data biokinetik diambil dari pencitraan dual SPECT/CT pada empat titik waktu. Time-activity curve diperoleh dari proses fitting menggunakan mono-exponential fit function dan fungsi objektif untuk optimasi kurva. Evaluasi fitting menggunakan kriteria kontrol goodness of fit (GoF) yaitu inspeksi visual kurva, koefisien determinasi (R2), dan koefisien variasi (KV). Nilai TIAC dihitung menggunakan integrasi numerik area under the curve (AUC) dari kurva hasil fitting. Kemudian, nilai TIAC  yang dihitung menggunakan  fitting tool dibandingkan dengan nilai TIAC dari software SAAM II sebagai referensi menggunakan % relative deviation (RD). Hasil studi  menggunakan fitting tool menunjukkan  inspeksi visual kurva melewati  sebagian besar titik data , nilai R2 mendekati 1 dan koefisien variasi parameter kurva secara umum < 50%. Evaluasi GoF pada pasien ke-5 dan ke-8 tidak memenuhi kriteria akibat underfitting. Hasil perhitungan TIAC dari fitting tool sebesar 1.013 ± 0.459 (jam) dan TIAC dari SAAM II sebesar 0.981 ± 0.390 (jam) serta nilai %RD < 1% . Studi awal kelayakan fitting tool memiliki kesesuaian yang baik terhadap SAAM II memenuhi kriteria kontrol GoF dan  %RD <10%. Fitting tool ini berpotensi sebagai software bantu dosimetri internal yang mudah diintegrasikan dengan workflow klinis, akses lebih mudah dan biaya terjangkau.
Verification of InaCAWO Model Surface Ocean Currents Based on HF Radar Data in the Labuan Bajo Waters Panji Kuswanaji; Aries Kristianto
BULETIN FISIKA Vol. 27 No. 2 (2026): BULETIN FISIKA
Publisher : Departement of Physics Faculty of Mathematics and Natural Sciences, and Institute of Research and Community Services Udayana University, Kampus Bukit Jimbaran Badung Bali

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24843/BF.2026.v27.i02.p14

Abstract

Labuan Bajo waters are a strategic maritime region with intensive tourism and marine transportation activities, making surface current information essential for maritime safety. This study aims to verify surface ocean current outputs from the InaCAWO model using HF Radar observations in Labuan Bajo as reference data. The study used surface current zonal (u) and meridional (v) components from InaCAWO and HF Radar for the period 1 December 2024 to 31 May 2025. Spatial resolution differences between the two datasets were adjusted using Natural Neighbor Interpolation, by interpolating HF Radar data onto the InaCAWO model grid. Model verification was conducted using statistical indicators, including Bias, Mean Absolute Error (MAE), Root Mean Square Error (RMSE), and Willmott Index, and supported by analyses of mean surface current, time series, scatterplots, and monthly spatial distributions of current components. The results show that InaCAWO is able to represent the general pattern of surface currents in Labuan Bajo waters, but tends to produce lower current magnitudes than HF Radar observations. The time series comparison shows a bias of -0.34 knot, an RMSE of 0.41 knot, and a correlation of 0.25, indicating a weak temporal relationship and an underestimation tendency. Verification of u and v components shows spatially and temporally varying errors, with greater uncertainty in the meridional component. Therefore, InaCAWO can serve as an initial representation of surface current conditions, but further evaluation is needed to improve its accuracy in capturing local current dynamics.
Performance Evaluation of ERA5 Reanalysis against Radiosonde Observations in Representing Atmospheric Vertical Variability on a Seasonal Scale in the Maritime Continent of Indonesia Muhizzadin Abdul Adzan; Petiwi Risky Setyowati; Yosafat Donni Haryanto
BULETIN FISIKA Vol. 28 No. 1 (2027): BULETIN FISIKA
Publisher : Departement of Physics Faculty of Mathematics and Natural Sciences, and Institute of Research and Community Services Udayana University, Kampus Bukit Jimbaran Badung Bali

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24843/BF.2027.v28.i01.p03

Abstract

ERA5 reanalysis is widely applied in meteorological studies, but its performance requires evaluation in regions with complex seasonal dynamics such as the Indonesian Maritime Continent (BMI). This study assesses the ability of ERA5 to represent seasonal atmospheric vertical variability using radiosonde observations. The analysis covers December 2021 to November 2024 at three stations, namely Soekarno-Hatta, Juanda, and I Gusti Ngurah Rai, for temperature, relative humidity, zonal wind, and meridional wind at eight standard pressure levels from 925 to 100 hPa. Evaluation methods include Hovmöller analysis, Mean Absolute Error (MAE), Mean Error (ME), correlation coefficient, scatter plots, and box plots for December–January–February (DJF), March–April–May (MAM), June–July–August (JJA), and September–October–November (SON) seasons. Results indicate that ERA5 represents temperature very well, with MAE values of 0.3 to 1.1°C and correlations exceeding 0.9, although errors increase at 100 hPa. Wind components also show high correlations above 0.9 but exhibit underestimated amplitudes, particularly for zonal winds during DJF. In contrast, relative humidity shows good agreement in the lower layers but significant limitations in the upper layers, with MAE values up to 58 percent, correlations below 0.6, and overestimation above 300 hPa. These findings confirm ERA5’s reliability for temperature and wind analyses, while humidity remains a key source of uncertainty in tropical maritime regions.
Characterizing the Meteorological Signature of Frost Events in the Dieng Highlands Didik Kurniawan; Aries Kristianto
BULETIN FISIKA Vol. 28 No. 1 (2027): BULETIN FISIKA
Publisher : Departement of Physics Faculty of Mathematics and Natural Sciences, and Institute of Research and Community Services Udayana University, Kampus Bukit Jimbaran Badung Bali

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24843/BF.2027.v28.i01.p01

Abstract

Frost in the Dieng Highlands is a localized agrometeorological hazard that appears during selected tropical highland nights, yet its recurring near-surface meteorological structure remains insufficiently documented using high-temporal-resolution observations. This study characterizes the meteorological signature of Dieng frost events using quality-controlled 10-minute Automatic Weather Station (AWS) observations from 2021 to 2025. Observations were arranged into nocturnal windows from 19:00 to 06:50 Western Indonesian Time and classified into frost and non-frost nights using 50 documented event dates. Temporal distribution, median nocturnal composite profiles, Mann-Whitney U tests, Cliff's delta, and Spearman correlation were applied to temperature, humidity, dew-point depression, wind speed, rainfall signal, cooling rate, and pressure. Among 1,819 analyzed nights, 50 were classified as frost nights, corresponding to 2.75% of the observation period. The events were concentrated in the dry-season months, especially July, followed by August and June. Frost nights showed a persistent nocturnal thermal pathway, with median night-mean and minimum temperatures of 6.11 °C and 2.65 °C. They were also calmer, had stronger negative cooling rates, and lower rainfall signals, whereas dew-point depression and relative humidity did not differ significantly between classes. These results indicate that Dieng frost is best understood as a combined cold, calm, humid, radiatively efficient, and seasonally dry nocturnal signature rather than as a low-temperature condition alone.
Nowcasting of Tropical Cyclone Intensity and Trajectory over Southern Indonesia Using a Temporal Convolutional Network Pertiwi Risky Setyowati; Yosafat Donni Haryanto; Adi Mulsandi; Latifah Nurul Qomariyatuzzamzami
BULETIN FISIKA Vol. 28 No. 1 (2027): BULETIN FISIKA
Publisher : Departement of Physics Faculty of Mathematics and Natural Sciences, and Institute of Research and Community Services Udayana University, Kampus Bukit Jimbaran Badung Bali

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24843/BF.2027.v28.i01.p02

Abstract

Tropical cyclones are extreme weather phenomena that generate strong winds, heavy rainfall, high waves, and infrastructure damage, necessitating rapid and accurate prediction methods to support early warning systems. This study aims to develop a Temporal Convolutional Network (TCN) model to forecast the short-term track and intensity of tropical cyclones at lead times of 6, 12, 18, and 24 hours within World Meteorological Organization (WMO) Regional Association V (RA V), covering waters south of Indonesia. Best-track data from the Australian Bureau of Meteorology (BOM) for 1973–2026 were used, comprising longitude, latitude, central pressure, and maximum wind speed. Cyclones Seroja, Cempaka, Dahlia, Anggrek, and Savanna served as independent test data, while the remaining data were chronologically split into 90% training (1973–2021) and 10% validation (2022–2026). At a 6-hour lead time, the RMSE for longitude, latitude, maximum wind speed, and central pressure were 1.87°, 0.33°, 2.50 knots, and 3.37 hPa, respectively, with R² values of 0.947–0.994. At 24 hours, RMSE increased to 2.70°, 1.25°, 6.76 knots, and 8.95 hPa; R² for longitude and latitude remained high (0.955 and 0.947), while R² for maximum wind speed and central pressure declined to 0.616 and 0.658. Spatially, the model captured the main trajectory pattern for most cyclones, though performance for Cempaka was relatively low. TCN proved more reliable for track than intensity prediction. Incorporating additional environmental variables is recommended to improve intensity prediction accuracy and strengthen Indonesia's tropical cyclone early warning system.
Comparison of Radiation Dose Received by Stroke Patients in 16-Slice Non-Contrast CT Scan Examination Firda Imroatus&#039; Saumi. A.; Sahara Hamas Intifadhah; Erlinda Ratnasari Putri
BULETIN FISIKA Vol. 28 No. 1 (2027): BULETIN FISIKA
Publisher : Departement of Physics Faculty of Mathematics and Natural Sciences, and Institute of Research and Community Services Udayana University, Kampus Bukit Jimbaran Badung Bali

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24843/BF.2027.v28.i01.p04

Abstract

Stroke is one of the diseases with a high incidence rate and often requires CT scan examination to establish a rapid and accurate diagnosis. The use of CT scan in stroke diagnosis involves exposure to ionizing radiation; therefore, it is important to consider the radiation dose received by patients. This study aims to analyze and compare the radiation doses received by stroke patients undergoing 16-slice non-contrast CT scan examinations based on age groups and gender. This study used a descriptive comparative method with a quantitative approach using secondary data in the form of CTDIvol and DLP values obtained from stroke patient data who underwent 16-slice non-contrast CT scan examinations. The obtained data were then used to calculate the effective dose using a standard conversion factor. Data analysis was conducted to determine the variation and differences in radiation dose values among different age groups and genders. The results showed that CTDIvol, DLP, and effective dose values in stroke patients varied based on age group and gender. Older age groups tended to have higher CTDIvol and DLP values compared to younger age groups. In addition, male patients showed slightly higher radiation dose values than female patients. However, the obtained radiation dose values were still within the reference range for head CT examinations. These findings provide an overview of the distribution of radiation doses in 16-slice non-contrast CT scan examinations and can serve as an evaluation for optimizing radiation dose usage while maintaining good image quality and ensuring patient safety.
Analysis of Integrated Vapor Transport and Atmospheric Dynamics During the Extreme Rainfall Event in Tangerang City (Case Study: January 28-29, 2025) Muhammad Fathurrachman Alghazali; Latifah Nurul Qomariyatuzzamzami; Yosafat Donni Haryanto; Avrionesti
BULETIN FISIKA Vol. 28 No. 1 (2027): BULETIN FISIKA
Publisher : Departement of Physics Faculty of Mathematics and Natural Sciences, and Institute of Research and Community Services Udayana University, Kampus Bukit Jimbaran Badung Bali

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24843/BF.2027.v28.i01.p05

Abstract

The extreme rainfall event in Tangerang City on 28 - 29 January 2025 caused flooding in several areas and disrupted flight activities at Soekarno-Hatta International Airport. This study aimed to analyze integrated vapor transport and atmospheric dynamics associated with the extreme rainfall event. The method used was descriptive quantitative research with a case study approach. The data consisted of three-hourly rainfall data from Soekarno-Hatta Meteorological Station and ERA5 ECMWF reanalysis data, including wind components, relative humidity, divergence, vorticity, vertical velocity, and water vapor transport at the 1000–300 mb layer. This study also analyzes atmospheric stability indices derived from Soekarno-Hatta radiosonde data, including the K-Index (KI), Lifted Index (LI), Showalter Index (SI), Total Totals Index (TT), CAPE, and SWEAT. The results showed that atmospheric conditions during the event were characterized by the strengthening of westerly to northwesterly winds at the 925 mb layer, high relative humidity of 80–100% in the lower to middle troposphere, strong upward motion, low-level convergence, and vorticity patterns that supported the development of convective clouds. The atmospheric stability indices also indicated marginally unstable conditions that supported convective potential, particularly through the K-Index (KI) values, which suggested an increased probability of heavy rainfall. Integrated vapor transport also indicated a large and persistent moisture supply from the western Java waters, the Sunda Strait, and the western Java Sea toward Tangerang City. Therefore, the extreme rainfall event is influenced by the combination of strong moisture supply and atmospheric dynamic conditions that support intense convection.
Analysis of Entrance Skin Exposure Values and Chest Area Dose Using Digital Radiography on a Custom ANSI Phantom Aandri; Sri Dewi Astuty; St. Hartina Anwar; Ikbal Ikbal; Syamsir Dewang; Ajeng Anggreny Ibrahim
BULETIN FISIKA Vol. 28 No. 1 (2027): BULETIN FISIKA
Publisher : Departement of Physics Faculty of Mathematics and Natural Sciences, and Institute of Research and Community Services Udayana University, Kampus Bukit Jimbaran Badung Bali

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24843/BF.2027.v28.i01.p07

Abstract

Chest radiography is one of the most frequently performed medical imaging procedures in radiology practice due to its ability to provide diagnostic information about the lungs and thoracic organs. This study aims to analyze the Entrance Skin Exposure (ESE) and radiation dose distribution in the thoracic cavity using Digital Radiography (DR) with a fabricated ANSI chest phantom. This experimental study was conducted in the Radiology Department of Dr. Tadjuddin Chalid Hospital, Makassar. The phantom was constructed using acrylic and aluminum materials with variations of air gaps of 5, 6, and 7 cm to simulate the thoracic cavity. The collected data included ESE values on the phantom surface and radiation doses within the thoracic cavity, which were further analyzed to determine the Entrance Skin Dose (ESD) and linear attenuation coefficient. The results show that ESE and ESD values increase with higher tube voltage and phantom thickness, but decrease as the FFD increases. Furthermore, the presence of air gaps within the thoracic cavity affects the attenuation process, resulting in lower radiation doses compared to denser materials. These findings indicate that exposure parameters and thoracic cavity structure significantly influence radiation dose distribution in chest radiography examinations.

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