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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 9 Documents
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Search results for , issue "Vol 12, No 2 (2022): Vol. 12 No. 2 Edition" : 9 Documents clear
Simulasi Pelelehan Freeze Plug Termodifikasi pada Molten Salt Reactor Menggunakan Metode Moving Particle Semi-implicit Nabiilah, Banafsaj Fatiya; Mustarib, Asril Pramutadi Andi; Yulianto, Yacobus
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 | Full PDF (1103.055 KB) | DOI: 10.26418/positron.v12i2.57434

Abstract

In the Molten Salt Reactor, the freeze plug is one of the components that plays an important role when a reactor accident occurs. In designing the freeze plug, the selection of the constituent material is based on the ability of the material to spread the heat. Therefore, studies on material selection are needed to provide information regarding freeze plug design. The modified freeze plug melting process has been simulated using the Moving Particle Semi-Implicit method. This study aims to observe the behavior of the modified freeze plug melting phenomena and to see the effect of the conductivity value on the melting process. The alloys used around frozen salts with different thermal conductivity are Hastelloy-N, Heynes-242, and ODS Alloy (MA754). The simulation results show that the time required for frozen salt to melt in Hastelloy-N, Heynes-242 variations , and ODS Alloy (MA754) are 12.3 seconds each; 12.7 seconds; and 24.3 seconds. The results obtained explain that freeze plugs with metal alloys that have the highest thermal conductivity require a shorter time to reach the melting point. This shows that the greater the thermal conductivity value, the easier it is to spread heat to the alloy that hits the frozen salt.
Perluasan Kinerja Akustik Limbah Kayu Batang Kelapa Sawit Termodifikasi Bahan Formaldehida Manik, Tetti Novalina; Shaliha, Shaliha; Siregar, Simon Sadok; Santoso, Tanto Budi; Yahya, Iwan; Mashuri, Mashuri; Zainuri, Muhammad; Darminto, Darminto
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 | Full PDF (442.893 KB) | DOI: 10.26418/positron.v12i2.55963

Abstract

Chemical modifications for waste oil palm trunks had carried out as acoustic material. This modification was conducted in two stages. Firstly, formalization with formaldehyde solution and secondly is impregnation with melamine-formaldehyde resin. Formalization was conducted in alkaline condition (pH 10) for 3 days and 5 days. Impregnation was carried out under pressure 3 bar and 5 bar and held for an hour. For completed these modification, the samples was cured at 120oC for 10 minutes and then dried at (103±2)oC to reached moisture content of less than 6%. This modification has changed the chemical structure and the morphology of wood, as shown by the FTIR and SEM results. The samples became denser, stronger and more rigid. Furthermore, the mechanical and physical properties of modified wood are also increasing. The absorption coefficient decreases with increasing formalization time and impregnation pressure. Based on trend of absorption coefficient, BKS wood can be applicated as resonant absorber with work class from A to class B and D.
Deteksi dan Kuantifikasi Internal Wave Menggunakan Instrumen Broadband Echosounder SIMRAD EK80 di Perairan Padang Bay Bali Situmorang, Edriyan; Manik, Henry Munandar; Atmadipoera, Agus Saleh
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 | Full PDF (750.216 KB) | DOI: 10.26418/positron.v12i2.51854

Abstract

Internal wave adalah gelombang laut yang terjadi di lapisan dalam di perairan laut dangkal dan dalam, di mana kemunculannya hanya dapat terjadi jika kolom air terstratifikasi akibat adanya perbedaan densitas massa air. Penelitian ini bertujuan untuk mendeteksi peristiwa internal wave, serta mengukur nilai hambur balik akustik dari internal wave yang terjadi di Selat Lombok. Data yang digunakan adalah hasil pengukuran instrumen broadband echosounder SIMRAD EK80 frekuensi 200 kHz tipe pulsa continuous wave (CW) dengan data pendukung elevasi muka air, suhu, salinitas, dan densitas dari Conductivity Temperature Depth (CTD) “Yoyo” selama 24 jam. Nilai hambur balik didapatkan dengan analisis menggunakan perangkat lunak Sonar5-Pro. Echogram menunjukkan adanya pembentukan nonlinear internal wave disertai dengan adanya turbulensi yang terjadi pada saat gelombang pasang membawa massa air dengan densitas berbeda melewati topografi kasar di Selat Lombok. Nilai backscatter hasil segmentasi berentang dari -75 dB sampai -59 dB.
Performance Analysis of Multiple Input Multiple Output (MIMO) Multi-Carrier Code-Division Multiple Access (MC-CDMA) Combined with Quasi-Orthogonal Space Time Block Coding (QO-STBC) in Rayleigh Fading Channel Kusumawardhani, Eka; Astuti, Rina Pudji; Adriansyah, Nachwan Mufti; Imansyah, Fitri; Putra, Leonardus Sandy Ade
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 | Full PDF (388.996 KB) | DOI: 10.26418/positron.v12i2.46613

Abstract

The need for a communication system with a higher data rate and mobility grows along with information and communication technology development. Combining MC-CDMA with the MIMO system and supporting the system with a good transmit diversity technique is a promising idea to provide the needed communication system, especially in high mobility conditions. MC-CDMA can support ubiquitous communications without affecting the achievable BER and is more capable of high-speed mobility. It integrates the benefit of both OFDM and CDMA. On the other hand, QO-STBC increases the bit rate without using additional bandwidth to transmit diversity in the MIMO system. So, this study proposed a system combining the MIMO MC-CDMA system with QO-STBC. The proposed system is investigated under high mobility conditions to see the system's performance. The simulation results show that our system performs better than the MC-CDMA STBC system and the QOSTBC system but not better than the MC-CDMA multilevel coding scheme. To reach the value of BER 10−3, MC-CDMA multilevel Coding requires less power, around 5 dB, than the proposed system.
Application of Unmanned Aerial Vehicles for Micro-Small and Medium Enterprises Agricultural in West Java Sawita, I Kadek Agus Sara; Evita, Maria; Kane, Hansel; Rausyanfikr, Fadhil; Djamal, Mitra
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 | Full PDF (565.014 KB) | DOI: 10.26418/positron.v12i2.54176

Abstract

Agricultural Micro-Small and Medium Enterprises (MSMEs) play a vital role in maintaining national food security. In terms of sources of economic growth, the agricultural sector is the largest contributor to West Java's economic growth in the first quarter of 2021. The agricultural business sector contributed as much as 0.94%, greater than its contribution in the fourth quarter of 2020 which amounted to 0.39%. MSMEs still have external and internal constraints, especially in terms of financing, product marketing, and lack of access to information. These constraints often hinder MSMEs in developing their business and expanding their market share. From various cases of marketing agricultural MSME products in West Java, it is necessary to implement technology to market agricultural commodities. One of them is a map application, which is useful in providing the location of agricultural MSMEs and how to reach that location from the customer's current location. So that sellers/farmers and buyers can do direct transactions. Therefore, map applications using Unmanned Aerial Vehicles (UAV) can be used as the alternative technology to solve that problem. While, this research only focuses on generating the map. UAV - DJI Phantom 4 Pro has been used in this research to take images at each location of the sample locations. To control the UAV automatically for each mission, it used Pix4D capture flight plans. The data were processed by Agisoft Metashape Professional software. The location of image data collection was carried out in various areas: a building, an open space area and a real small and medium agriculture enterprises location. Two-dimensional maps and 3D maps of these areas have been successfully created. The average RMS error is 0.17 (2.88 pixels) indicating under 1% of the average error.
The Electrical Characteristic Analysis of Reduced Graphene Oxide in Pt-Free DSSC Using Single Diode Model and Electrochemical Impedance Spectroscopy Aprilia, Annisa; Yuliasari, Fitri; Siregar, R.E; Syakir, Norman; Bahtiar, Ayi; Safriani, Lusi; Hidayat, Sahrul; Hanipah, Iip; Fitrilawati, Fitrilawati
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.v12i2.54272

Abstract

We studied the characteristic of reduced graphene oxide (rGO) as a counter electrode (CE) in Pt-free dye-sensitized solar cell (DSSC) using single diode model equation based on current density-voltage (J-V) measurement. The electrical characteristics of DSSC was investigated by electrochemical impedance spectroscopy (EIS) in order to knowing the catalytic properties of rGO as counter electrode. The rGO thin film as CE was deposited on fluorine-doped tin oxide (FTO) substrate and stacked with FTO/TiO2/ruthenium dye/mosalyte/rGO/FTO DSSC structure. The rGO film was obtained from GO (graphene oxide) film that was thermally reduced at 200°C for one hour under argon flow. The performance of DSSC with rGO as CE was characterized by current-voltage measurement and the interface between each layer was observed by Electrochemical Impedance Spectroscopy (EIS).   The device efficiency (η) of DSSC that used GO and rGO film as CE are 0.09% and 3.43%, respectively. DSSC parameters such as series resistance (RS) shunt resistance (RSH), and ideality factor (n) were obtained from J-V curve which analyzed using single diode model equation. All samples have a Rs value of 2 indicates that all devices have a good ohmic contact. The RSH of device using rGO-1mg/ml is increase (from 2850 to 3670 Ω.cm2) compared with GO indicate that thermal reduction is successes. The rGO film shows a comparable performance to Pt-conventional CE thus it is a good candidate as alternative of DSSC counter electrode.
Integration of Topex Satellite Gravity and DEM SRTM Imagery for Subsurface Structure Identification at Tiris Geothermal Area, Lamongan Volcano Complex, Probolinggo, East Java Siombone, Salman Hamja; Susilo, Adi; Maryanto, Sukir
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.v12i2.56880

Abstract

Tiris area is one area that has geothermal prospects. Tiris area is located in the Tiris sub-district, Probolinggo regency, East Java. This study aims to identify the subsurface structure of the Tiris geothermal area using Topex gravity and DEM SRTM imagery data. The Topex gravity data obtained is still in Free Air Anomali (FAA) form, so it is necessary to make Bouguer and terrain corrections to get a complete Bouguer anomaly. A residual Bouguer anomaly is needed to study shallow subsurface structures. This anomaly is obtained by separating the residual and regional anomalies from the complete Bouguer anomaly using the moving average method. The study area has residual Bouguer anomaly values ranging from -0.5 to 2.9 mGal. The low residual Bouguer anomalies are seen in the body of the Lamongan volcano (LV) and the Tiris geothermal area (TGA). The study of subsurface structures is focused on the LV and the TGA through Forward 2D modeling. The A-A' cross-section illustrates the subsurface of LV, while the B-B' cross-section illustrates the subsurface of TGA. Cross-section A-A' modeling results show that the source of the low anomaly is in the second layer D2 = 1.24 g/  at a depth of 4.0 to 0.6 km below sea level and is suspected to be magma because it has a low density. Cross-section B-B' modeling obtained a low anomaly source at the second layer D2 = 2.03 g/  at a depth of 4.0 to 2.8 km below sea level and is suspected to be intrusive rock. The lineament display on the 2D of DEM SRTM map for the 45o and 135o azimuths shows that the TGA region has a high lineament density, and the orientation of the surface geological structure in the study area is dominant in a northwest-southeast direction.
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.

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