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All Journal Jurnal Penelitian Pendidikan IPA (JPPIPA) Journal on Education Eksakta : Berkala Ilmiah Bidang MIPA Jurnal Pendidikan, Sains, Geologi, dan Geofisika (GeoScienceEd Journal) Journal of Experimental and Applied Physics
Zulhendra Zulhendra
Universitas Negeri Padang
Agriculture, Biological Sciences & Forestry Astronomy Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Civil Engineering, Building, Construction & Architecture Computer Science & IT Control & Systems Engineering Education Electrical & Electronics Engineering Energy Engineering Environmental Science Materials Science & Nanotechnology Mathematics Mechanical Engineering Physics

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Inert Gas Axial Flow Analysis on Thermal System with Natural Convection Condition Rio Anshari; Mairizwan Mairizwan; Fandi Oktasendra; Debi Rianto; Zulhendra Zulhendra
EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 24 No. 01 (2023): Eksakta : Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464)
Publisher : Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/eksakta/vol24-iss01/338

Abstract

The Fukushima nuclear accident in 2011 became the basis for consideration of the use of gas as a coolant in nuclear reactors. This is because the convection rate of gas flow in the cooling channel can occur naturally due to differences in density and does not require the help of a pumps for the circulation of the coolant. This study aims to analyze how the flow pattern of an inert gas on a vertical-axial reference by natural convection in a thermal system. The focus of this research is to study the flow parameters of the coolant with a gas phase. This research is an experimental study. The analysis was carried out using a descriptive approach and computer simulation-assisted numerical analysis methods. The results showed that the distribution and variation of heat was radially dominant in the middle so that the coolant channel wall received less heat load. The magnitude of the pressure drop along the vertical-axial channel shows a homogeneous pattern and decreases radially from center to edge. These results indicate the use of inert gas as a coolant can be considered as an alternative coolant in heat systems that do not depend on pumps in operating conditions.
Analisis Kebutuhan Pengembangan Bahan Ajar Digital Fisika Berbasis Project Based Learning Terintegrasi Pendekatan STEM Selma Riyasni; Intan Purnama Yani; Widia Kemala Sari; Zulhendra Zulhendra
Journal on Education Vol 6 No 1 (2023): Journal On Education: Volume 6 Nomor 1 Tahun 2023
Publisher : Departement of Mathematics Education

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31004/joe.v6i1.3775

Abstract

21st century learning is suggested to be based on information and communication technology, for example using digital teaching materials. The learning model used is an innovative learning model that improves students' 21st century skills such as project based learning which is also suggested in the independent curriculum. The use of project based learning learning models is considered effective if it integrates the STEM approach. The initial step in developing STEM-integrated PjBL-based digital teaching materials is to conduct an analysis of the needs of teachers and students. The purpose of this study is to describe the results of the analysis of the needs for the development of digital teaching materials based on the integrated PjBL learning model with the STEM approach. The subjects of this study were 22 physics teachers and 50 students of SMAN 2 Bukittinggi. Data collection through questionnaires, then analyzed to obtain conclusions. The conclusions from this study show 1) learning still does not use digital teaching materials, 2) it is necessary to develop teaching materials based on the PjBL learning model that is integrated with STEM to assist student project assignments.
Implementation of the Gauss-Kronrod Quadrature Method (G7, K15) on 2D Gravity Anomaly Modeling in Basins with a Polynomial Variation of Density Distribution with Depth Zulhendra; Wahyu Srigutomo; Cahyo Aji Hapsoro
Jurnal Penelitian Pendidikan IPA Vol 10 No 8 (2024): August
Publisher : Postgraduate, University of Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29303/jppipa.v10i8.8493

Abstract

Forward modeling of 2D gravity anomalies, considering density contrasts that vary polynomially with depth, was performed to examine basin structures. This process involved two main stages: deriving analytical formulas and executing numerical integration. The Gauss-Kronrod Quadrature Method, utilizing 7 Gauss points and 15 Kronrod points, was employed to precisely compute these integrals. Initial modeling applied to theoretical basement scenarios with fixed density contrasts showed gravity anomalies that accurately reflected the curvature of the basement. To validate the approach, it was then applied to real-world cases including the Sebastian Vizcaino Basin, San Jacinto Graben, and Sayula Basin. By incorporating suitable density contrasts, modeling lengths, and basement curvature shapes, the results revealed that both fixed-density and depth-variable density models produced gravity anomalies with patterns consistent with the actual basement curvature. These findings validate the modeling technique’s effectiveness in representing real geological features accurately. The study confirms that the Gauss-Kronrod Quadrature Method (G7, K15) is robust for analyzing 2D gravity anomalies, providing a reliable tool for understanding the influence of varying density contrasts on gravity responses.
Analysis Of Seismic Rate Change Based On Spatial Distribution Of Seismotectonics And Deformation Extension In West Nusa Tenggara Aprimanda Mulya Rizki, Rifa; Syafriani; Amir, Harman; Zulhendra, Zulhendra
Jurnal Pendidikan, Sains, Geologi, dan Geofisika (GeoScienceEd Journal) Vol. 6 No. 1 (2025): Februari
Publisher : Mataram University

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Abstract

Wilayah Nusa Tenggara Barat memiliki aktivitas kegempaan yang tinggi. Sebelum terjadinya suatu kejadian gempa bumi, terlebih dahulu didahului oleh keadaan seismik tenang. Tujuan dari penelitian ini untuk mengetahui perubahan laju seismik yang diamati dari fenomena seismik tenang dan luas deformasi. Metode perubahan laju seismik yang digunakan adalah distribusi spasial z-value. Dan metode luas deformasi yang digunakan adalah rumusan Utsu dan Seki untuk gempa bumi M7,0 pada tanggal 5 Agustus 2018 dengan input magnitudo permukaan. Penelitian ini menggunakan data dari website USGS periode 1983-2023. Pada penelitian ini terdapat tiga zona fokus penelitian yaitu gempa bumi tahun 2009 (M6,6), gempa bumi tahun 2018 (M7,0) dan gempa bumi tahun 2018 (M6,9). Dengan menggunakan metode distribusi spasial z-value, wilayah dibagi menjadi beberapa grid. Nilai z dihitung pada setiap grid dan menggambarkan perubahan laju seismik. Fenomena tersebut dapat dilihat berdasarkan perubahan laju seismik yang telah diperoleh. Hasil yang diperoleh, pada zona pertama terjadi peningkatan aktivitas seismik sebelum gempa bumi 2009, zona kedua dan zona ketiga terjadi fenomena seismic quiescence yang mendahului gempa bumi 2018. Berdasarkan sebaran spasial z-value awal tahun 2023, terjadi fenomena penurunan aktivitas seismik di sebagian wilayah Nusa Tenggara Barat. Serta terjadi deformasi sebesar 1.091,44 km2 pada gempa bumi M7,0 tanggal 5 Agustus 2018. Hal ini patut diduga sebagai awal gejala gempa bumi di masa mendatang .
Analysis Of Seismic Quiescence Precursors Before The M7.4 Earthquake Of 28 September 2018 In Central Sulawesi Based On Seismotectonic Spatial Distribution And Earthquake Fracture Lengths zu, Zurahma; Syafriani; Dwiridal, Letmi; Zulhendra, Zulhendra
Jurnal Pendidikan, Sains, Geologi, dan Geofisika (GeoScienceEd Journal) Vol. 6 No. 1 (2025): Februari
Publisher : Mataram University

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Abstract

The Central Sulawesi earthquake with coordinates 2°30‘S -1°50’ N and 119°0'-124°20 E magnitude 7.4 in Palu, Donggala Regency on 28 September 2018. This earthquake was a significant and destructive earthquake in Central Sulawesi. A significant earthquake is preceded by a seismic quiescence. The aim of the study was to determine when the seismic quiescence occurred and seismic activity after the earthquake alongside fracture length. The method of analysis of seismic quiescence and fracture length is z-value and Wells and Coppersmith equation. Data processed with MATLAB and Zmap were 1478 events from 1983-2023. The study area is divided into several grids with sizes of 0.1°* 0.1°. The number of earthquakes included (N = 800, 700, 600, 500, 400, 300, and 200). The z-value was calculated for each grid based on the earthquake data organized in one grid and seismic activity after earthquake. The results of the analysis of the z-value calculation in each grid show of seismic quiescence before a significant earthquake. Based on the results of the spatial distribution of z-value in Central Sulawesi, the seismic quiescence preceded the 28 September 2018 earthquake event (M 7.4) by about 21 years beginning in 1990. When cut at 2019.6, there was a decrease in seismic activity again, which indicated that an earthquake would occur, so it was thought to be a trigger factor for future earthquake precursors. While the fracture length of the 7.4 Mw earthquake of 104,232 meters shows a positive correlation between magnitude and fracture length.
Estimation Of Maximum Ground Acceleration Value Based On Mentawai Earthquake Scenario Using Atkinson Boore and Zhao Khairunnissa, Shafira; Syafriani; Fauzi, Ahmad; Zulhendra, Zulhendra
Jurnal Pendidikan, Sains, Geologi, dan Geofisika (GeoScienceEd Journal) Vol. 5 No. 4 (2024): November
Publisher : Mataram University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29303/goescienceed.v5i4.510

Abstract

We have estimated the value and intensity of maximum ground acceleration in West Sumatra based on the Mentawai earthquake scenario by using the formulation of Atkinson Boore (2003) and Zhao (2006). This study aims to determine the PGA value of an area as the level of activity and intensity of the earthquake in West Sumatra region from the Mentawai earthquake scenario as a measure of damage caused by the earthquake and analyze its distribution. This study uses earthquake information data for the period 1900-2023 with magnitude > 7 SR and depth < 100 km and shear wave velocity model at a depth of 30 meters (Vs 30) sourced from the National Earthquakes Information Center US Geological Survey (NEIC/USGS) catalog. After that, calculations are carried out so that the estimated maximum ground acceleration value is obtained using the Atkinson Boore (2003) and Zhao (2006) formulas. The maximum ground acceleration and earthquake intensity values for each city/regency in West Sumatra were calculated with a 0.1° grid. The estimation results show that the largest values for each scenario are in Mentawai Islands and South Pesisir because those areas are close to the subduction zone. In addition, it is also influenced by the epicenter, magnitude and soil type in the region. So that the maximum ground acceleration value in West Sumatra ranges from 0.007 g - 2.117 g with earthquake intensity ranging from I - X+ MMI. This indicates that the area is vulnerable to damage if an earthquake occurs. Keywords: Earthquakes, Atkinson Boore, Zhao, PGA, Intensity
Magnetic Susceptibility of nanoparticles in the Lubuk Basung Region Anisa Janna; Hamdi Hamdi; Harman Amir; Zulhendra Zulhendra
Journal of Experimental and Applied Physics Vol 2 No 4 (2024): December Edition
Publisher : Department of Physics, Universitas Negeri Padang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/jeap.v2i4.87

Abstract

Nanoparticles is particles that have size very small, generally in range from 1 to 100 nanometers. Nanoparticles have one​ uniqueness with exists characteristic superparamagnetic. Characteristic superparamagnetic is properties the material has magnetization tall if given external magnetic field, however when No There is external magnetic field mark the average magnetization is zero. On size certain, nanoparticles can show transition from superparamagnetic to ferromagnetic or antiferromagnetic. Influence size grain and structure crystal to characteristic magnetic is one​ method in determine susceptibility. Susceptibility magnetic is defining constant​ big small a material to magnetized. Study This aim to the analyze mark susceptibility magnetic from nanoparticles rock floating in the area Lubuk Basung. Method used​ is method magnetism rock with tool Bartington Magnetic Susceptibility Meter Type B. Research results shows in the area Lubuk Basung LBS 23-02 and LBS 23-03 are available concentration content high Fe element and concentration content element Ti more low. Magnetic susceptibility in the area Lubuk Basung have characteristic antiferromagnetic magnetism, and has type grain almost no There is details superparamagnetic and also has mixture superparamagnetic and granular rough or details superparamagnetic <0.05 μm equivalent with <50 nm. So that depicted that size nanoparticles contained in the sample rock floating LBS 23-02 and LBS 23-03 have size nanoparticles below 50 nanometers with characteristic antiferromagnetic magnetism.
Co-Authors AA Sudharmawan, AA Anisa Janna Aprimanda Mulya Rizki, Rifa Debi Rianto Fandi Oktasendra Hamdi Hamdi Hapsoro, Cahyo Aji Harman Amir Intan Purnama Yani Khairunnissa, Shafira Letmi Dwiridal Mairizwan Mairizwan Rio Anshari Riyasni, Selma Syafriani Wahyu Srigutomo Widia Kemala Sari zu, Zurahma