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All Journal Jurnal Matematika & Sains JOIV : International Journal on Informatics Visualization Jurnal Biodjati Saintifik : Jurnal Matematika, Sains, dan Pembelajarannya
Purqon, Acep
Institut Teknologi Bandung
Biochemistry, Genetics & Molecular Biology Computer Science & IT Earth & Planetary Sciences Mathematics Physics Other

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The Effects of Atomic Substitutions (Bismuth, Gallium, Arsenic) on Electronic and Magnetic Properties of Carbon Nanotubes Aprilia, Ely; Muttaqien, Fahdzi; Purqon, Acep; Suprijadi, Suprijadi
Jurnal Matematika dan Sains Vol 20 No 1 (2015)
Publisher : Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Investigations of carbon nanotubes (CNT) properties by substituting impurity atoms are interesting, since the the defects show different properties and potentially wide applications. In this paper, we investigate the effects of atomic substitutions (Bismuth, Gallium, Arsenic) on electronic and magnetic properties of CNT by using Density Functional Theory method with Generalized Gradient Approximation. Our results show that Bismuth and Arsenic doped on zigzag CNT (10, 0) give the band gap and magnetic moment 0.19 eV and 2 μB, respectively. In contrast, Gallium doped shows no band gap and change the semiconductor properties of zigzag edge CNT (10, 0) into metal. Furthermore, the moment magnetic for Gallium-Arsenide doped CNT (10, 0) is 1 μB. Keywords: Atomic substitution, Band gap, Carbon nanotubes (CNT), DOS, Impurity.   Pengaruh Atom Pengganti (Bismut, Galium, Arsenik) pada Sifat Elektronik dan Magnetik Karbon Nanotube Abstrak Kecacatan pada struktur CNT mengakibatkan adanya perubahan sifat elektronik dan magnetiknya. Perubahan sifat inilah yang menyebabkan CNT  menarik untuk diteliti karena berpotensi memiliki aplikasi yang luas. Pada penelitian ini, dibahas mengenai  efek dari atom pengganti (Bismut, Galium dan Arsen) pada sifat elektronik dan magnetik CNT(10,0) yang dihitung dengan menggunakan teori fungsional kerapatan dan Generalized Gradient Approximation. Hasilnya menunjukan bahwa atom pengotor Bismut dan Arsen pada CNT (10,0) menghasilkan band gap sebesar 0.19 eV dan momen magnetik sebesar 2 μB. Sedangkan atom pengotor Galium tidak menghasilkan band gap pada CNT(10,0) dan mengubah sifat semikonduktor CNT(10,0) menjadi metal. Dari perhitungan didapatkan juga magnetik momen pada CNT (10,0) dengan atom pengotor Galium dan Arsen sebesar 1 μB. Kata kunci: Atom pengganti, Band gap, Karbon nanotube, DOS, Ketidakmurnian.
Simulasi Aliran Plasma dengan Variasi Kecepatan Injeksi Plasma pada Potensial Penghalang dalam Posisi Melayang Faisal, Muliady; Purqon, Acep
Jurnal Saintifik Vol 4, No 2 (2018): volume 4 nomor 2 juli 2018
Publisher : Fakultas MIPA UNSULBAR

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31605/saintifik.v4i2.179

Abstract

Dalam penelitian ini akan diperlihatkan bentuk difusi aliran plasma yang terjadi akibat variasi kecepatan injeksi plasma pada sebuah potensial penghalang dalam posisi melayang pada kasus distribusi kerapatan muatan dan daerah potensial listrik yang diturunkan dari persamaan Poisson. Metode yang digunakan dalam penelitian ini adalah Particle-In-Cell (PIC). Dalam metode PIC, elektron dan proton merupakan sumber dari plasma. Secara numerik step waktu yang digunakan dalam penelitian yaitu setiap 1 detik dengan periode plasma selama 200 detik dan grid yang digunakan yaitu 20 x 20. Adapun potensial penghalangnya berbentuk persegi. Dari variasi kecepatan injeksi berpengaruh terhadap kerapatan muatan sehingga jika kecepatan injeksinya diperbesar maka akan terdapat daerah kosong yang tidak terisi dibelakang potensial penghalang. Sedangkan untuk daerah potensial listrik jika kecepatan injeksi plasmanya diperbesar maka daerah dibelakang potensial penghalang akan terdapat daerah yang berpotensial yang lebih kecil.Kata kunci: Plasma, PIC, Potensial penghalang
Effect of Growth Space on The Productivity of Maize Using Three Sisters Cultivation with Bee Pollination Putri, Nadia Damika; Purqon, Acep; Putra, Ramadhani Eka
Jurnal Biodjati Vol 8 No 2 (2023): November
Publisher : UIN Sunan Gunung Djati Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15575/biodjati.v8i2.19227

Abstract

he increasing number of food needs is one of the driving factors for increasing agricultural production, but there are constraints on the availability of land. A polyculture system with corn, beans, and pumpkins, commonly known as the three sisters, can create positive interactions that can enhance the growth and development of each plant. This system has a vast potency to be applied to urban farming inside a grow bag because it does not require ample space, the placement of plants is flexible, and it produces a variety of yields. However, it is necessary to assess the effect of growing space on the growth of maize (Zea mays) cultivated by the three-sister system. This study used a completely randomized design with three treatments and six replications. The treatment consists of three planting spaces with various growing bags (treatment A:75 L, B:100 L, and C:200 L). The results of this study showed that the highest corn productivity was in the largest growing space (treatment C), which weighed 318.40 g/cob, and without husks 246.42 g/cob, but not significantly different from treatment B (grow bag 100 L), which weights 316.20 g/cob and without pods of 240.63 g/cob. This study found that the 100 L grow bag was the optimal growing space for planting corn in containers using the three sisters technique.
Geometry Representation Effectiveness in Improving Airfoil Aerodynamic Coefficient Prediction with Convolutional Neural Network Zikri, Arizal Akbar; Defianti, Hanni; Hidayat, Wahyu; Purqon, Acep
JOIV : International Journal on Informatics Visualization Vol 7, No 3 (2023)
Publisher : Society of Visual Informatics

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30630/joiv.7.3.1577

Abstract

Many applications use symmetric or asymmetric airfoils, such as aircraft design, wind turbines, and heat transfer. Each airfoil has different aerodynamic coefficients. Obtaining the aerodynamic coefficients is a must to optimize the airfoil design. Engineers use various methods to get the airfoil aerodynamic coefficients. A prediction method is an approximation approach that effectively reduces time and cost. This article uses convolutional neural networks (CNN) to get approximation values of those coefficients. In CNN, we collect 8920 aerodynamic coefficients for 223 NACA 4 as labels in datasets by using XFOIL at  and  with varying angles of attacks starting  to  with increment of . The simulation results are compared to the experiment using E387 airfoil for validation. Then, airfoil geometries as part of input datasets were transformed into Grayscale and RGB images using the signed distance function (SDF) and mesh algorithm. Each airfoil representation was trained using an 80% dataset and tested using a 20% dataset with Adam as an optimizer to generate each prediction model using modified LeNet-5. We use three different layer depths in modified LeNet-5 to obtain the optimal layer number. There is no remarkable improvement when varying the depth layers, so four layers are used instead. Simulation results show that using an SDF with Fast Marching Method on CNN predicts the most effective for the airfoil’s lift, drag, and pitch moment coefficient with varying angles of attack simultaneously. One can extend the method by using SDF to recognize different flow conditions.
Co-Authors Aprilia, Ely Defianti, Hanni Faisal, Muliady Muttaqien, Fahdzi Putri, Nadia Damika Ramadhani Eka Putra Suprijadi Suprijadi Wahyu Hidayat Zikri, Arizal Akbar