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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 222 Documents
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Implementasi Convolutional Neural Network dalam Menentukan Tingkat Kematangan Jeruk Siam Pontianak Berdasarkan Citra Sutanto, Yuris; H., Cindy Priscilla; Nurhasanah, Nurhasanah; Wahyuni, Dwiria; Arman, Yudha; Hasanuddin, Hasanuddin
POSITRON Vol 12, No 2 (2022): Vol. 12 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.v12i2.64594

Abstract

Pada umumnya, pemilihan jeruk dilakukan secara manual menggunakan pengamatan berdasarkan tingkat kematangannnya. Namun cara tersebut dianggap kurang efektif karena membutuhkan waktu lama dan tingkat keakuratan yang berbeda. Seiring berkembangnya teknologi, cara alternatif yang dapat dilakukan untuk mengidentifikasi suatu objek adalah dengan melakukan pengolahan citra. Penelitian ini bertujuan untuk mengkomparasi tingkat kematangan jeruk siam Pontianak berdasarkan citra menggunakan metode Convolutional Neural Network (CNN). Citra jeruk akan dibagi menjadi 2 kelas (belum matang dan sudah matang) dan 3 kelas (belum matang, tepat matang, dan terlalu matang). Citra yang digunakan sebanyak 120 data yang diambil menggunakan kamera smartphone. Pembagian citra dilakukan dengan menggunakan metode k-means clustering yang parameter pengelompokannya berdasarkan data hasil pengukuran kadar gula jeruk siam Pontianak dan data hasil ekstraksi fitur menggunakan metode Gray Level Co-occurrence Matrix (GLCM). Citra yang telah dikelompokkan akan di komparasi menggunakan metode CNN. Hasil akurasi yang diperoleh adalah 75% untuk citra berdasarkan data gula dengan 3 kelas, untuk citra berdasarkan data GLCM dengan 3 kelas sebesar 41.67% dan untuk 2 kelas sebesar 77.38%. Hasil tersebut mampu untuk menentukan tingkat kematangan buah jeruk. Akan tetapi berdasarkan parameter karakteristik, CNN hanya mampu mendapatkan akurasi yang baik pada 2 kelas saja
Seismic Site Classification Using the Multichannel Analysis of Surface Waves Method Syamsuddin, Erfan; Aswad, Sabrianto; Assegaf, Muhammad Alimuddin Hamzah; Rasimeng, Syamsurijal; Sakka, Sakka; Syamsuddin, Syamsuddin; Nasri, Muhammad; Syihab, Mufly Fadla
POSITRON Vol 12, No 2 (2022): Vol. 12 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.v12i2.53869

Abstract

The soil has a variety of qualities that affect its ability to support the weight of a structure. One of these features is soil stiffness, which can be determined using the surface wave method to prevent soil collapse. Multichannel Analysis of Surface Waves (MASW) is one of the non-invasive methodologies used in this study to investigate subsurface structures in North Sumatra, Indonesia. This method utilizes the dispersion properties of Rayleigh waves, producing a dispersion curve to get the shear wave velocity (Vs) through inversion. The shear wave velocity can be used to examine the soil stiffness qualities. The dispersion curve explains the relationship between shear wave velocity and depth, which can subsequently be used as a site class parameter. This survey uses three lines with one shot for each line which uses thirty geophones. The seismic source used is a gun with the type M16.38 Cal. Each line consists of 30 geophones with a distance of 5 m. The entire track is 160 m long and lasts for 2048 seconds with a sampling rate of 0.00025 seconds. The average shear wave velocity measured at three measurements was 372.5 m/s on line P1, 347.1 m/s on line P2A, and 311.0 m/s on line P2B, respectively. Overall, the soil classification on the P1 line is class C, and the P2A and P2B lines are class D, which is suitable for development planning areas.
Identification and Classification of Thiamine with Amperometric Biosensor Based on Saccharomyces cerevisiae and Principal Component Analysis Umar, Lazuardi; Rosandi, Vira Annisa; Nainggolan, Leonardus Riski; Setiadi, Rahmondia Nanda; Linda, Tetty Marta
POSITRON Vol 13, No 1 (2023): Vol. 13 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.v13i1.59432

Abstract

Vitamin B1 (thiamine) plays an important role in various metabolic processes and is one of the main factors in the body's health. Thiamine excess and deficiency in the body might cause a variety of diseases such as shortness of breath, beriberi, and heart failure, hence thiamine levels must be detected as a reference for intake. The present research detected thiamine using the amperometric biosensor method and the yeast Saccharomyces cerevisiae as a bioreceptor. Dissolved oxygen (DO) level measurement parameters are considered based on yeast cell metabolism. Thiamine was treated with various concentrations of 15 mM, 30 mM, 45 mM, 60 mM, and 75 mM. The measurement results are in the voltage range of 1912–1964 mV, where the addition of thiamine causes an increase in the reproducibility and growth rate of yeast cells. The ideal characteristics of the biosensor based on the parameters of sensitivity, linearity, and stability was also carried out, which resulted in successive biosensor measurements of 0.925 mV/mM, a correlation coefficient of r = 0.9868, and a decrease in the voltage response of the biosensor up to 4.97% from its initial activity. The measured data were grouped and classified using principal component analysis (PCA), which resulted in a total accumulated data variance percentage of 84.5% and an eigenvalue > 1 for both PCs. It is intended that the findings of this research can be utilized as a reference for controlling vitamin consumption levels that have an impact on health.
Protonation Process of Porous Silica Cluster Surface using Molecular Dynamics Method Alfaridzi, Raihan; Nugroho, Bintoro Siswo; Rosandi, Yudi
POSITRON Vol 13, No 1 (2023): Vol. 13 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.v13i1.63670

Abstract

Using molecular dynamic simulation, we developed an algorithm to protonate the surface of an amorphous porous silica grain particle model and study its effect. In this work, the silica grain model can be used to study cosmic dust coagulation. The surface of the silica cluster was protonated by placing H atoms on oxygen atoms having only a single bond, namely, the non-bridging oxygens. The H atoms are placed opposite the Si–O bond with a distance of around 1 Å to form silanol (Si–O–H) group termination on the silica surface. The angular conformation of the silanol was optimized by relaxing the surface at low temperature. We evaluated the number of silanol groups, the angular distribution of the Si-O-H bond, and the average distance between Si-O particles using the radial distribution function (RDF). The result of the study shows that minimizing the energy of the silica surface changes the angular distribution of the silanol from 180° to about 110° and between 140°-160°. However, the average distance between Si-O particles remains at 1 Å, which demonstrates the correctness of the atomic interaction model. The addition of protons on the silica surface is an essential factor in the simulation of cosmic dust collision since the modification of the surface chemistry may alter the contact surface energy, thus changing the probability of particle coagulation.
Synthesis of NaP Zeolite Based on Bauxite Red Mud Using Hydrothermal Method on Mole Ratio of SiO2/Al2O3 Variations Eviva, Nur; Shofiyani, Anis; Sayekti, Endah
POSITRON Vol 13, No 1 (2023): Vol. 13 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.v13i1.60099

Abstract

Red mud is a bauxite industrial waste of reddish-brown mud with high alkalinity. Red mud has relatively high silica and alumina content, so it can be utilized as a raw material in the synthesis of zeolite. This study aims to synthesize high-purity NaP zeolite from red mud at various SiO2/Al2O3 mole ratios. The synthesis begins with neutralizing the red mud, followed by decomposition using the alkaline fusion method at a ratio of red mud:NaOH = 1:1 (w/w). The filtrate produced by the alkaline fusion was adjusted to the mole ratio of SiO2/Al2O3 = 2.0; 2.5; 3.0; and 4.0, respectively, by adding sodium silicate, followed by a hydrothermal process using an autoclave at 120oC for 16 hours. The synthesized zeolites were characterized using XRD and FTIR spectrophotometry. The XRD results showed that the zeolite produced in all variations of the SiO2/Al2O3 mole ratio studied was a type of high-purity NaP with no other zeolite crystalline phases found as impurities. The structure formed is tetragonal with a degree of crystallinity of 74.54%; 76.47%; 78.94%; 75.64%, and crystal size 80.2286; 54.3437; 37.7099 and 40.1226 nm for zeolite with SiO2/Al2O3 mole ratio 2.0; 2.5; 3.0; and 4.0, respectively. Based on the results of the study, pure NaP zeolite can be synthesized from red mud material using the hydrothermal method at the ratio of moles SiO2/Al2O3 = 2.0 – 4.0.
One Step Synthesis of TiO2-Activated Carbon Composite Using Hydrothermal Method with Mass Variation of Activated Carbon Sutisna, Sutisna; Rokhmawati, Ilma Eka Nur; Misto, Misto; Rofi’i, Imam; Mulyono, Tri; Siswanto, Siswanto; Supriyanto, Edy; Wibowo, Edy
POSITRON Vol 13, No 1 (2023): Vol. 13 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.v13i1.59856

Abstract

One effort to increase the photocatalytic activity of TiO2 is to immobilize it on the surface of the sorbent material. This study aims to produce TiO2-Activated Carbon (TiO2-AC) composites which have higher photocatalytic activity than TiO2, using a simple method. The synthesis of TiO2-AC  composites was carried out using the hydrothermal method. The synthesis process was initiated by mixing TTIP, ethanol, H2O, and activated carbon with various masses (5 g, 10 g, 15 g, and 20 g). The mixture was then put into a hydrothermal autoclave and heated at 180°C for 12 hours. The material is then washed until the pH is neutral, and then dried. The TiO2-AC composite powder was then calcined at 500°C for 3 hours. Based on the photocatalytic test of the TiO2-AC composite on the degradation of methylene blue compounds, it was shown that composite with a mass variation of 10 g activated carbon (TiO2-AC/10) had the highest photocatalytic activity. FTIR characterization of the sample TiO2-AC/10 showed a shift in the peak wave number of the hydroxyl and carbon groups. Meanwhile, the results of morphological analysis using SEM showed that TiO2 particles had adhered to the AC surface, which was also confirmed by EDX data in the presence of Ti and O elements in the synthesized material. The results of the crystallinity analysis showed that the 100% synthesized TiO2 was the anatase phase with a crystalline size of 1.80−14.14 nm. This study open up opportunities for the development of TiO2-based composite materials for large-scale environmental remediation applications.
Green Synthesis of Fe3O4 Nanoparticles Based on Natural Sand as Methylene Blue Degradation by Electrocoagulation Method Fatimah, Siti; Juharni, Juharni; Wahyuni, Angraeni Sri Hanifa
POSITRON Vol 13, No 1 (2023): Vol. 13 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.v13i1.63779

Abstract

The green synthesis of Fe3O4 nanoparticles based on natural sand as a liquid waste degrader has been conducted. Fe3O4 powder was obtained by separating natural sand using a permanent magnet through the electrocoagulation method with Mn doping and AC composite. The 5 variations of Mn doping aimed to induce ferromagnetic properties and stabilize MnxFe3-xO4 particles as methylene blue degraders, while the AC composite aimed to enhance pollutant absorption. Characterization using Fourier Transform Infrared and X-Ray Diffraction analyzed the functional groups, nanostructure, and crystal size of MnxFe3-xO4 powder, showing that increasing the molarity of Mn doping strengthened functional group bonds and stabilized particle size up to 8.389 Å. The magnetic nanocomposite powder was applied to a methylene blue solution as a model for textile liquid waste. Ultraviolet Visible Light testing revealed decreased light absorbance in the surface state region and an energy bandgap widening of 5.25 eV. The larger energy bandgap indicated a lower refractive index, indicating the clarity of the resulting liquid. COD and BOD testing supported these findings, as samples with 0.3M and 0.7M doping showed a decrease in COD from 299.82 mg/L to 287.27 mg/L and a decrease in BOD from 127.08 mg/L to 115.16 mg/L. The characterization results demonstrated that the magnetic nanocomposite powder MnxFe3-xO4/AC effectively served as a methylene blue degrader. It transformed the sample colour into a clearer state and reduced pollutant levels, complying with the wastewater quality standard. This research offers an environmentally friendly solution for a cost-effective and efficient methylene blue degrader.
Beneath the Surface: Identifying Subsurface Caves in "Gua Pandan" Using Integrated Electrical Profiling Method Antosia, Risky Martin; Akbar, Hendra Hidayat; Santoso, Nono Agus; Putri, Intan Andriani; Farishi, Bilal Al; Natalia, Happy Christin
POSITRON Vol 13, No 1 (2023): Vol. 13 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.v13i1.63558

Abstract

One of the geopark tourism areas in East Lampung Regency, "Gua Pandan," has run into rock subsidence on the surface. As part of the subsidence prevention, indirect electrical methods between resistivity and chargeability profiling were applied to identify the presence of a subsurface cave in the study area. Two measurement lines were carried out with Wenner Alpha and Wenner Schlumberger arrays. Because the depth target is shallow (approximately 10 m) and to obtain a better resolution, each line has a stretch length of 70 m and 2 m electrode spacing. A line was measured over a known underground cave to produce a desired outcome, and the other was in an area with no cavities. Based on the results from each profile of resistivity and chargeability, an air-filled target has a value of over 5,000  and under 6 ms, respectively. Then, integrated processing of both methods generated a metal factor (MF) profile to view the presence and estimated shape of the cave/ cavities. The result represents that an MF value under 1.5 ms/Ωm is a cavity, and solid rock is over 1.5 ms/Ωm. Also, the MF level from both configurations delineates a similar section. However, a modest difference occurs in estimating the cavity shape geometry,  for Wenner Apha and  for Wenner Schlumberger. Furthermore, this study can be an initial step in safety assessment in the area.
Potential of Cellulose Acetat Separator of Empty Palm Oil Fruit Bunches and Polyvinylidene Fluoride for Energy Storage Applications Ginting, Delovita; Na Duma, Tulus; Rahmadani, Nofia; Suryani, Yola; Haryanti, Rismadani
POSITRON Vol 13, No 1 (2023): Vol. 13 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.v13i1.63784

Abstract

One of the components that play an important role in maintaining battery security is the separator. The separator plays a role in preventing short circuits due to direct exchange between the anode and cathode in the battery cell. To avoid leakage or short circuit during the process, the separator must have good mechanical properties. For this reason, modifications are needed to improve the characteristics of the separator. The modification process was carried out by mixing Poyvinylidene Fluoride (PVDF) and cellulose acetate (CA) polymers. The CA used in this study was obtained by utilizing natural waste extracts in the form of empty oil palm fruit bunches (EFB). This study aims to see the effect of variations in the addition of CA EFB and PVDF on the characteristics of the resulting separator. Synthesized CA EFB was characterized using Fourier Transfor Infrared (FTIR) spectroscopy which showed that cellulose had been successfully synthesized into cellulose acetate.. The separator produced in this study showed good electrolyte absorption, indicated by the occurrence of an oxidation-reduction reaction process on the hysteresis curve with a wider and reversible loop upon the addition of 0.2 g CA. The mechanical characteristics of the separator also increased with the addition of CA concentration, the separator with the addition of 0.3 g CA showed the highest tensile strength value of 62.335 MPa and the highest porosity value of 89.35%. The separator with the addition of 0.3 g of cellulose acetate also decomposes more quickly, indicated by a weight loss percentage of 60%. The results of this test indicate that the addition of CA EFB and PVDF can affect the physical and mechanical characteristics of the separator which has the potential to become a battery separator.
Utilization of Luminescent Carbon Nanodots from Soybean Husk Wastes for Fingerprint Identification using Tracker Software Spectrum Analysis Dwandaru, Wipsar Sunu Brams; Hidayatullah, Abdul Rosyid; Listari, Eka Sentia Ayu; SL, Deby Grace
POSITRON Vol 13, No 1 (2023): Vol. 13 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.v13i1.57863

Abstract

Visible fingerprints (FPs) play a crucial role in forensic identification, and luminescent carbon nanodots (C-Dots) have shown promise in enhancing their visibility. However, the optimal concentration of C-Dots for effective coating remains largely unexplored. This research aimed to determine the ideal C-Dots concentration for FPs identification. The fingerprint (FP) patterns of two subjects, L and P, were analyzed, revealing intensity peaks in 200 mm - 250 mm and 100 mm - 150 mm, respectively. The FP patterns were observed using a light microscope and Tracker software spectral analysis. The C-Dots samples were produced with variation in concentrations of (%W/V) 40%, 43.4%, and 47.6%. The spectrophotometer ultraviolet-visible (UV-Vis) test of the C-Dots showed absorption peaks at 270 nm and 330 nm wavelengths. The photoluminescence test indicated that the C-Dots have cyan luminescence. The X-ray diffraction (XRD) test showed that the C-Dots were amorphous. The spectrometer Fourier transform infrared (FTIR) test showed the presence of C = C functional groups. The scanning electron microscope (SEM) images with 5000x magnification showed the surface morphology of the C-Dots mimicking crumpled papers. Using Tracker software, FPs were successfully differentiated, with the clearest visual FPs observed when using a C-Dots concentration of 43.4%. Thus, the optimal concentration of C-Dots for FP identification was 43.4%. 

Page 17 of 23 | Total Record : 222

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