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POSITRON
Published by Universitas Tanjungpura
ISSN : 23014970     EISSN : 2549936X     DOI : http://dx.doi.org/10.26418/positron.v10i2.42006
Core Subject : Science,
Energy Physics
POSITRON: Berkala Ilmiah Fisika (POSITRON) is a peer-reviewed open accessed Indonesian journal that publishes scientific research papers in the field of physics and its application. The journal covers a wide range of topics in physics, including conceptual studies, theoretical and experimental studies, the use of computational methods, instrumentation, and multidisciplinary studies involving physics. This journal aims to be a platform to exchange research results in physics-related topics across all scientific disciplines. POSITRON is published by Jurusan Fisika, Fakultas Matematika dan Ilmu Pengetahuan Alam, Universitas Tanjungpura, Indonesia, twice a year (Mei and November). This journal is accreditated SINTA 2 by RISTEKDIKTI and indexed in Directory of Open Access Journal (DOAJ), Bielefeld Academic Search Engine (BASE), Google Scholar, Science and Technology Index (Sinta), Garda Rujukan Digital (GARUDA), and Indonesia One Search (IOS). All articles in this journal are uniquely identified with DOI.
Arjuna Subject : Fisika dan Astronomi - Fisika Nuklir dan Energi Tinggi
Articles 230 Documents
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Studi Pemanfaatan Abu Boiler Kelapa Sawit (Palm Oil Fuel Ash) dan Limbah Karbit Sebagai Campuran Beton Putri, Rinka Carolina; Silalahi, Imelda Hotmarisi; Zaharah, Titin Anita; Widiyantoro, Ari
POSITRON Vol 15, No 2 (2025): Vol. 15 No. 2 Edition
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam, Univetsitas Tanjungpura

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26418/positron.v15i2.88882

Abstract

Penelitian ini bertujuan untuk mengetahui komposisi optimum beton dari campuran semen, palm oil fuel ash (POFA), dan limbah karbit berdasarkan nilai kuat tekan dan ketahanannya dalam media asam dan media garam. Metode penelitian meliputi preparasi beton dimana 30% semen diganti dengan campuran POFA dan limbah karbit. Komposisi campuran POFA dan limbah karbit divariasikan sesuai dengan persentase (%) POFA:limbah karbit 70:30; 60:40; 50:50 dan 40:60. Komposisi terbaik yang ditetapkan adalah beton dengan nilai kuat tekan tertinggi. Terhadap beton terbaik tersebut (disebut beton campuran) dianalisis komposisi unsur, diuji ketahanannya dalam media asam dan garam kemudian dibandingkan dengan beton tanpa campuran POFA dan limbah karbit. Metode untuk menguji ketahanan dalam media asam dan garam dilakukan dengan cara perendaman beton dalam media selama 28 hari kemudian diuji kuat tekannya. Berdasarkan hasil uji kuat tekan beton, diketahui bahwa komposisi terbaik pengganti 30% semen adalah campuran dari 60% POFA dan 40% limbah karbit, dengan nilai kuat tekan 40,49 MPa. Nilai ini memenuhi standar beton mutu normal (SNI 03-6468:2000, ACI 318) namun lebih rendah daripada beton tanpa penggantian semen (disebut beton kontrol). Hasil pengamatan terhadap ketahanan beton dalam media asam maupun garam menunjukkan bahwa nilai kuat tekan beton campuran relatif bertahan setelah mengalami perlakuan dalam kondisi asam maupun garam. Dibandingkan dengan beton kontrol, beton campuran lebih tahan dalam kondisi tersebut, mengimplikasikan potensi campuran POFA dan limbah karbit sebagai pengganti sebagian semen dalam beton.
Identifikasi Lapisan Tanah Menggunakan Metode Geolistrik sebagai Kajian Awal Land Application di Desa Tinting Boyok Kabupaten Sekadau Zulfian, Zulfian; Hosea, Jeremi; Sutanto, Yuris
POSITRON Vol 15, No 2 (2025): Vol. 15 No. 2 Edition
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam, Univetsitas Tanjungpura

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26418/positron.v15i2.92188

Abstract

Limbah cair kelapa sawit dapat dimanfaatkan sebagai pupuk bagi tanaman kelapa sawit. Penelitian ini bertujuan untuk mengidentifkasi lapisan di bawah permukaan tanah khususnya di land application yang dapat digunakan sebagai rekomendasi lokasi pembuatan flatbed. Metode geolistrik resistivitas diterapkan untuk menduga lapisan di bawah permukaan tanah menggunkan konfigurasi Wenner-Schlumberger. Lintasan berjumlah 3 buah dengan panjang masing-masing 195 m. Data lapangan yang diperoleh kemudian dimodelkan menggunakan metode least squares inversion. Kedalaman lapisan yang diperoleh dari hasil inversi adalah 39,4 m. Hasil model dari ketiga lintasan, nilai resistivitas yang diperoleh adalah 8,54 Ωm hingga 1082 Ωm. Lapisan di bawah pemukaan diduga terdiri dari pasir, pasir lempungan, dan granodiorit lapuk. Lapisan pasir diduga memiliki nilai resistivitas sebesar 8,54 hingga 42,9 Ωm dan lapisan ini diduga mengandung air tanah. Lapisan pasir lempungan diduga memiliki nilai resistivitas sebesar 42,9 hingga 215 Ωm, dan lapukan batuan granodiorit memiliki nilai resistivitas sebesar 215 hingga 1082 Ωm. Lapisan pasir lempungan dan lapisan granodiorit lapuk yang direkomendasikan untuk pembangunan flatbed karena diduga berkategoi kurang permeable. Zona flatbed yang direkomendasikan pada lintasan L1 memiliki panjang total 135 m, lintasan L2 memiliki panjang total 140 m, dan lintasan L3 memiliki panjang 120 m. Pendugaan lapisan tanah dan rekomendasi posisi flatbed dapat digunakan oleh pemangku kepentingan untuk merancang dan membuat flatbed.
Role of Dimensionality on Quantum Atkinson Engine Performance Based on the Potential Well Using Two Lowest Energy Levels under Equal Heat Leakage in Hot and Cold Reservoirs Saputra, Yohanes Dwi; Romido, Verby; Sibarani, Nikita Renovich Burju; Apriwandi, Apriwandi; Friska, Vira; Rafitasari, Yeti; Zulfa, Zulfa
POSITRON Vol 16, No 1 (2026): Vol. 16 No. 1 Edition
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam, Univetsitas Tanjungpura

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26418/positron.v16i1.105349

Abstract

This study theoretically investigates the influence of system dimensionality (1D, 2D, 3D) on the performance of a quantum Atkinson engine, a cycle consisting of two isentropic, one isochoric, and one isobaric stroke. This engine is modeled as a quantum analog of the classical ideal gas in a piston-cylinder, where the working fluid is a spinless particle confined in a one-, two-, or three-dimensional potential well, utilizing its two lowest energy states. In the absence of heat leakage, a fundamental decoupling is observed, as the compression ratio increases, thermal efficiency shows negligible variation across different dimensions, yet power output scales linearly with dimension. Under heat leakage, the lower-dimensional system is more efficient at low leakage, but proven to be more thermodynamically fragile, as its efficiency and reversibility degrade most rapidly as the leakage increases. A lower-dimensional system also consistently yields lower power output for a certain efficiency. This highlights a core nano-engine design consideration, balancing the high-power output of multi-dimensional systems against the thermal instability of lower dimensions.
Modification of Organic Dyes Cnidoscolus Aconitifolius Chlorophyll Hybrid with Dye Synthetic N719 with TiO2 Semiconductor Combination to Improve DSSC-Solar Cell Performance Pote, Fernince Ina; Dilak, Hory Iramaya
POSITRON Vol 16, No 1 (2026): Vol. 16 No. 1 Edition
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam, Univetsitas Tanjungpura

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26418/positron.v16i1.92932

Abstract

This research Solar energy is a renewable and environmentally friendly alternative energy source with enormous potential to be converted into electricity through Dye Sensitized Solar Cell (DSSC) technology. The efficiency of DSSC depends strongly on the sensitizer, semiconductor layer, and counter electrode. In this study, the effect of modifying organic chlorophyll dye extracted from Cnidoscolus aconitifolius, hybridized with synthetic dye N719, and combined with the semiconductor TiO₂ was investigated to enhance DSSC performance. The fabrication process employed low-cost methods, including spin coating, slip casting, drop casting, and soaking techniques, to obtain homogeneous TiO₂ thin films and maximize dye adsorption. Optimization of temperature and soaking duration was carried out to support the formation of crystal size, morphology, and anatase phase of TiO₂, which are crucial for electron transport. The counter electrode was prepared with Pt (Hexachloroplatinic (IV) acid 10%), functioning as an effective catalyst to accelerate redox reactions with the electrolyte. Performance testing using a Keithley instrument revealed that the hybrid dye N719: Cnidoscolus aconitifolius with a concentration of 0.1% wt achieved the highest conversion efficiency of 0.82%. The absorption spectrum confirmed that the hybrid dye effectively absorbed light in the range of 400–800 nm, demonstrating the synergistic role of natural and synthetic dyes in improving photocurrent generation. This research provides insights into the utilization of chlorophyll-based natural dyes from Cnidoscolus aconitifolius combined with synthetic dyes to produce eco-friendly DSSCs and highlights the potential of fabrication techniques to reduce production costs and supports the development of sustainable solar cell technologies.
Intermediate Band Characteristics of Defective Perovskite Cs2SnI6 in Comparison with CsSnI3: Insights into Its Role as Hole Transport Material for Solar Cells Handayani, Yolla Sukma; Sukmawati, Sri; Nurunnizar, Adhita Asma
POSITRON Vol 16, No 1 (2026): Vol. 16 No. 1 Edition
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam, Univetsitas Tanjungpura

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26418/positron.v16i1.99039

Abstract

Tin-based halide perovskites have recently attracted attention as promising alternatives to toxic lead-based perovskites for solar cell applications. This study aims to investigate the electronic and optical properties of cesium tin hexaiodide (Cs2SnI6) and to elucidate its functional role in perovskite solar cells, particularly in determining whether it is more suitable as a light absorber or as a hole transport material (HTM). For comparison, the properties of cesium tin tri-iodide (CsSnI₃) are also systematically analyzed using Density Functional Theory (DFT) calculations within the Perdew-Burke-Ernzerhof (PBE) functional and Heyd-Scuseria-Ernzerhof 2006 (HSE06) hybrid functional frameworks. While previous theoretical studies have predominantly examined these materials separately, a comprehensive understanding of the role of defect-induced intermediate bands in Cs2snI6 remains limited. The results reveal that CsSnI₃ exhibits a direct band gap, while Cs₂SnI₆ shows an intermediate band (IB) located between the valence band maximum (VBM) and conduction band minimum (CBM). The calculated band gap of Cs₂SnI₆ is 0.28 eV using PBE and 0.82 eV using HSE06, confirming the role of Sn(5s) and I(5p) states in the IB formation. Furthermore, optical property calculations further demonstrate that Cs₂SnI₆ exhibits a relatively high dielectric constant and distinct absorption features associated with interband transitions, although with lower absorption intensity compared to CsSnI₃. These findings suggest that CsSnI₃ is suitable as a light absorber, whereas Cs₂SnI₆ is more favorable as an HTM in perovskite solar cell architectures. Overall, this work offers new insights into the functional role of Cs₂SnI₆ and its potential contribution for efficient lead-free perovskite solar cells.
Three-Dimensional Soliton Propagation in Ruby for High-Stability Optical Communication Yantidewi, Meta; Firdaus, Rohim Aminullah; Khoiro, Muhimmatul; Winarno, Nanang; Ramadani, Riski; Nikmah, Afiyah; Alhusni, Hanan Zaki
POSITRON Vol 16, No 1 (2026): Vol. 16 No. 1 Edition
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam, Univetsitas Tanjungpura

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26418/positron.v16i1.93213

Abstract

Optical communication in digitalisation is a significant catalyst in supporting high-speed and large capacity data transmission. However, optical communication applications face substantial challenges, such as energy loss, dispersion effects, and signal stability over long transmission distances. One material that has the potential to overcome these problems is ruby due to its nonlinear characteristics. This research work numerically investigates soliton propagation in ruby material analysis as a Nonlinear Schrödinger Equation numerical modelling and three-dimensional visualisation with Cubic B-Spline, modified Korteweg-de Vries-Zakharov-Kuznetsov, and Boussinesq methods to understand ruby material characteristics more deeply. The simulations show that the soliton waveform remains stable during propagation, with its amplitude confined within approximately -1.05 to 0.35, indicating robust shape preservation under anisotropy and temperature variations. like most previous studies that are limited to one or two dimensional modelling or to dispersive fibre media, this study implement a full 3D NLSE framework tailored to the physical properties of ruby. The results show that both numerical modelling and three-dimensional visualisation indicate that ruby material can maintain the soliton waveform during propagation. This finding suggests that ruby has the potential to be applied in optical communication systems with high stability to support long-distance data transmission.
Role of the Sunda Strait in Water Mass Exchange and Circulation between the Java Sea and the Indian Ocean: a CROCO Model Experiment Rahmawitri, Herwi; Atmadipoera, Agus Saleh; Hamzah, Faisal; Xu, Tengfei
POSITRON Vol 16, No 1 (2026): Vol. 16 No. 1 Edition
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam, Univetsitas Tanjungpura

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26418/positron.v16i1.83286

Abstract

The Sunda Strait is the only shallow passage connecting the Sunda Shelf seas (including the Java Sea) to the eastern Indian Ocean, and it strongly influences near-surface circulation and the South Java–Sumatra upwelling system. Using a high-resolution three-dimensional CROCO configuration, we conduct paired numerical experiments with the strait open (control) and artificially closed to quantify its role in regional water-mass exchange and hydrographic variability. The control simulation indicates a seasonal reversal of exchange, with an intrusion of Indian Ocean water into the Java Sea during the northwest monsoon (DJF), contrasting with southward export during the southeast monsoon (JJA). The meridional volume transport varies between −0.47 Sv (southward) and 0.42 Sv (northward), with a mean of -0.13 ± 0.17 Sv (1 Sv = 10⁶ m³ s⁻¹). The closure (OFF-strait) experiment reveals the Sunda Strait acts as a crucial gateway that allows warmer and fresher Java Sea water to enter the Indian Ocean. When the strait is closed, this export is blocked, leading to higher sea surface height and stronger surface circulation on the Java Sea side, while sea surface temperature decreases on the Indian Ocean side—especially during JJA—consistent with enhanced upwelling. Conversely, the closure prevents salty and colder Indian Ocean water from penetrating into the Java Sea. Overall, the strait modulates both the intensity of South Java–Sumatra upwelling and the strength of surface circulation. These results improve understanding of Sunda Strait dynamics and provide a physical basis for assessing implications for marine productivity, fisheries, and climate-driven variability.
Numerical Analysis of Metric Perturbations, Spacetime Curvature, and Gravitational Wave Polarizations in Linearized General Relativity Using the Finite Difference Method Ariefka, Reza; Siagian, Ruben Cornelius; Sahroni, Taufik Roni; Nurahman, Arip
POSITRON Vol 16, No 1 (2026): Vol. 16 No. 1 Edition
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam, Univetsitas Tanjungpura

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26418/positron.v16i1.92372

Abstract

The general theory of relativity states that small perturbations in the spacetime metric in a weak gravitational field can be treated as perturbations propagating on the Minkowski background. Although the analytical formulation of Einstein's linear equations has been well developed, numerical studies that integrate local metric perturbations, the curvature structure of space-time through the Ricci tensor, the dynamics of gravitational wave polarization, and reduction to Newton's law of gravity in a two-dimensional domain are still limited. This research aims to numerically analyze the behavior of metric perturbations and space-time curvature in the framework of linear general relativity and verify its consistency with gravitational wave theory and Newtonian gravity at weak field and low velocity limits. The study is limited to a linearized approach, two-dimensional flat spacetime, harmonic and transverse–traceless gauge conditions, and ideal sources in the form of Gaussian perturbations and source-free waves. The methods used include the theoretical formulation of linearized general relativity and the Finite Difference Method (FDM) numerical approach to discretize the Laplace operator and wave equation with the FTCS scheme. The results show that Gaussian perturbations produce highly localized curvature with a global Ricci tensor contribution approaching zero. Gravitational wave simulations show the dominance of energy in polarization (h_+)\ over (h_\times), as well as numerical verification of the relationship (h_{00}=-2\phi), which confirms the reduction of general relativity to Newton's laws. This research fills a research gap by integrating metric analysis, curvature, and gravitational waves into a single consistent numerical framework. The novelty of this research lies in Gaussian modeling and integrated FDM-based numerical analysis as a conceptual bridge between general relativity and classical mechanics.
Effect of Mackerel (Scomberomorus Commerson) Bone-Derived Gelatin on Alum Performance in Coagulation–Flocculation Processes Ramadhan, Aditya Nur; Zaharah, Titin Anita; Sayekti, Endah
POSITRON Vol 16, No 1 (2026): Vol. 16 No. 1 Edition
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam, Univetsitas Tanjungpura

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26418/positron.v16i1.88690

Abstract

Mackerel fish bones are commonly discarded as waste and may contribute to environmental pollution. This study aimed to extract gelatin from mackerel fish bones and evaluate its use as a coagulant aid with alum for the removal of organic matter and total suspended solids (TSS) from peat water. Gelatin was extracted and its functional groups were characterized using Fourier transform infrared (FTIR) spectroscopy. Treatment performance was evaluated through jar test experiments by varying Gelatin dosage (2, 4, 6, 8, and 10 g/L) and pH (4–8). Organic matter concentration was determined using the permanganometric titration method, while TSS was measured using the nephelometric method. The gelatin yield was 2.45%, and FTIR analysis confirmed the presence of amide functional groups, indicated by N–H stretching at 3353 cm⁻¹. The addition of gelatin enhanced alum performance, with optimal conditions at a dosage of 8 g/L and pH 7, achieving removal efficiencies of 89.3% for organic matter and 87.8% for TSS with a sedimentation time of 15 minutes. These findings demonstrate the potential of fish bone–derived gelatin as an effective and sustainable coagulant aid for peat water treatment
Effect of Hydrochloric Acid Leaching on the Elemental Composition and Photocatalytic Properties of Puya Sand, Local Gold Mining Residues From Sintang, West Kalimantan Silalahi, Imelda Hotmarisi; Khairiyah, Uun Rabi'atul; Zaharah, Titin Anita; Widiyantoro, Ari
POSITRON Vol 16, No 1 (2026): Vol. 16 No. 1 Edition
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam, Univetsitas Tanjungpura

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26418/positron.v16i1.88656

Abstract

Pasir puya merupakan residu yang dihasilkan dari penambangan emas dengan metode pendulangan (panning) yang mengandung unsur-unsur seperti ZrO2, TiO2  dan Fe2O3, sehingga berpotensi untuk digunakan sebagai fotokatalis. Namun, kandungan Fe2O3yang masih cukup tinggi pada pasir puya dapat mengurangi aktivitas fotokatalitiknya. Oleh karena itu, penelitian ini bertujuan untuk menentukan konsentrasi HCl terbaik dalam pelindian untuk mengurangi kandungan Fe2O3  dan mengetahui aktivitas fotokatalitiknya dalam mengurangi konsentrasi metilen biru (MB) pada kondisi gelap, cahaya tampak dan sinar UV. Metode penelitian meliputi preparasi, reaksi fusi alkali, pelindian dan aktivasi. Selanjutnya, dikarakteriasi menggunakan  X-Ray Flurescence  (XRF) dan  Diffused Reflectance Spectroscopy  (DRS UV-Vis). Uji aktivitas fotokatalitik dilakukan dengan memvariasikan waktu kontak kemudian konsentrasi MB diukur menggunakan spektrofotometer UV-Vis. Hasil XRF menunjukkan bahwa rasio Ti/Fe pada pelindian dengan HCl 3 M meningkat dari 0,62 menjadi 0,79. Berdasarkan analisis DRS UV-Vis material yang dihasilkan memiliki nilai celah-pita yang sesuai dengan komposit TiO2/Fe2O3  yaitu 2,62-2,88 eV. Selain itu, analisis XRD mengidentifikasi puncak difraksi muncul pada sudut 2θ yang menunjukkan keberadaan fase ZrO2  monoklinik, TiO2  anatase, hematit (α-Fe2O3) dan TiO2  rutil. Material yang telah mengalami proses fusi alkali, pelindian dan aktivasi memperlihatkan kemampuan mengurangi konsentrasi MB dalam keadaan gelap sedangkan kemampuan mengurangi konsentrasi MB dibawah iradiasi sinar tampak dan Uv tidak jauh berbeda dari keadaan gelap, hal ini menandakan bahwa material belum fotoaktif. Uji fotokatalitik menunjukkan bahwa pasir yang mengalami pelindain 3 M menunjukkan aktivitas fotokatalitik dalam mengurangi konsentrasi MB pada keadaan dibawah sinar tampak dann UV dibandingkan dengan HCl 4 dan 5 M.

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