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All Journal Jurnal Sains dan Seni ITS UNEJ e-Proceeding BAREKENG: Jurnal Ilmu Matematika dan Terapan ASRO JOURNAL - STTAL Limits: Journal of Mathematics and Its Applications International Journal of Computing Science and Applied Mathematics Sewagati
Chairul Imron, Chairul
Departemen Matematika, Institut Teknologi Sepuluh Nopember (ITS)
Arts Humanities Computer Science & IT Control & Systems Engineering Decision Sciences, Operations Research & Management Economics, Econometrics & Finance Education Energy Engineering Industrial & Manufacturing Engineering Languange, Linguistic, Communication & Media Mathematics Mechanical Engineering Physics Public Health Social Sciences Transportation Other

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Numerical Simulation of Fluid Flow Around Circular Cylinder and Three Passive Controls to Reduce Drag Coefficient at Re=500 Chairul Imron; Amirul Hakam; Basuki Widodo; Tri Yogi Yuwono
(IJCSAM) International Journal of Computing Science and Applied Mathematics Vol 6, No 1 (2020)
Publisher : Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (739.569 KB) | DOI: 10.12962/j24775401.v6i1.5331

Abstract

Numerical experiments and simulations of fluid flow through the outer surface of a circular cylinder and three passive controls have been investigated to determine the proper configuration of three passive controls in reducing the drag coefficient. One of passive controls is placed in front of the cylinder with distance ratio (S:D) = 2:4 and the other two passive controls are placed behind the cylinder with distance ratio (T:D) = 1:6;1:8. The angle between two passive controls behind the cylinder are a =30 deg;60 deg;90 deg;120 deg. The Navier-Stokes equations for incompressible, viscous and unsteady fluid flows is solved based on SIMPLE (Semi-Implicit for Pressure-Linked Equations) algorithms and discretized using finite-difference method. The difference in a affects the reduction in the drag coefficient significantly. The best configuration of three passive controls design is one of passive controls put at the distance ratio S=D = 2:4;T=D = 1:6 and a = 60. This configuration can reduce the drag coefficient optimally to 21.2109%.
PREVENTIVE MAINTENANCE ANALYSIS ON THE KELVIN HUGHES MKVII X-BAND NAVIGATION RADAR IN WARSHIP TYPE-Z Basuki Basuki; Chairul Imron; Eko Krisdiono
JOURNAL ASRO Vol 12 No 4 (2021): International Journal of ASRO
Publisher : Indonesian Naval Technology College - Sekolah Tinggi Teknologi Angkatan Laut - STTAL

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Abstract

Navigation Radar has a very vital role for the readiness of KRI operations. However, with the age of the KH MKVII X-Band radar on the KRI Type-Z class which has reached eleven years and is faced with high operational tasks, making the radar has a high risk of damage. While the repair process takes quite a long time, especially if it requires replacement of spare parts. Therefore, preventive maintenance is needed to maintain radar readiness. In this study using FMECA to determine critical components and reliability to determine the replacement time of critical components with a minimum reliability of 0.65. The results of FMECA,analysis Risk Matrix, data distribution and reliability of 17 components obtained 5 components withcategory risk rating a high, namely Modulator RPN value of 365.25 with a proposed replacement of 3482 hours, Tx Microcontroller value of RPN 302.62 with a proposed replacement of 5803 hours, LNFE RPN value of 261.75 with proposed replacement of 5887 hours, Power Supply Trx value of RPN 260,05 with proposed replacement of 5498 hours and Magnetron with RPN value of 256.12 with proposed replacement of 5148 hours. By following the proposed component replacement before the component is damaged, it can save a budget of 12.87% or Rp. 27,612,000.00. Keywords: FMECA, Risk Priority Number, Reliability, Risk Rating
MAGNETOHIDRODINAMIKA FLUIDA MIKROPOLAR PADA LAPISAN BATAS MELEWATI PELAT DATAR YANG DIPENGARUHI KONVEKSI CAMPURAN Jason Otniel Dharmanta; Basuki Widodo; Dieky Adzkiya; Chairul Imron
UNEJ e-Proceeding 2022: E-Prosiding Seminar Nasional Matematika, Geometri, Statistika, dan Komputasi (SeNa-MaGeStiK)
Publisher : UPT Penerbitan Universitas Jember

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Abstract

This study considers about the magnetohydrodynamics of micropolar fluids in the boundary layer passing through a flat plate which is affected by mixed convection. The governing equations are obtained from the continuity, momentum, energy equations, and Maxwell’s equation. The micropolar fluid passes through the flat plate, flowing from the below. The obtained dimensional equations are then transformed into non-dimensional equations using non-dimensional variables, then transformed into similarity equations. The similarity equations can be introduced using stream functions, that produce non-linear partial differential equations. The equations are then solved by Keller-Box method. The numerical results obtained are in the form of temperature and fluid velocity profiles with variations in magnetic parameters, micropolar parameters, porosity parameters and Prandtl numbers. The numerical simulation results show that the greater the magnetic parameter (), the micropolar parameter () and the porosity parameter (), respectively, then the speed decreases but the temperature increases. However, the variation of the Prandtl numbers () does not affect the speed. The greater the Prandtl number, the lower the temperature. Keywords: Flat plate, Keller-Box, magnetohydrodynamics, micropolar fluid
Peningkatan Kompetensi Guru dan Siswa SMAN 1 Kraksaan dan SMAS Taman Madya Kraksaan untuk Menghadapi Olimpiade Sains Kabupaten (OSK) Bidang Matematika dan Informatika di Kabupaten Probolinggo Fahim, Kistosil; Subiono; Imron, Chairul; Herisman, Iis; Soleha; Mufid, Muhammad Syifa’ul
Sewagati Vol 8 No 2 (2024)
Publisher : Pusat Publikasi ITS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j26139960.v8i2.897

Abstract

Pelatihan guru matematika dan siswa-siswanya di SMAN 1 Kraksaan dan SMAS Taman Madya Kraksaan memberikan pendalaman dan pemahamaan konsep mata pelajaran Matematika, dikhususkan bagaimana seorang guru matematika dan siswanya dapat memecahkan permasalahan/penyelesaian soal-soal OSK bidang matematika dan informatika. Kegiatan pelatihan ini telah disepakati dengan jadwal mengikuti program dari SMAN 1 Kraksaan dan SMAS Taman Madya Kraksaan dengan pelaksanaan secara luring. Hasil dari pelatihan ini: 1) guru-guru dapat mentransfer materi pelatihan pada anak-anak didiknya dan 2) siswa-siswa (sebagai peserta pelatihan) dapat mentransfer materi pelatihan pada teman-teman dan adik kelasnya. Target luaran dari kegiatan ini adalah meningkatnya kemampuan peserta dalam menyelesaikan soal-soal OSK bidang Matematika dan Informatika. Hal ini bisa dilihat dari nilai post-test yang nilainya lebih baik daripada nilai pre-test.
Peningkatan Kapabilitas Guru dan Siswa SMA di Yayasan Pendidikan Pesantren Zainul Hasan Genggong untuk Menghadapi Olimpiade Sains Kabupaten (OSK) bidang Matematika dan Informatika di Kabupaten Probolinggo Fahim, Kistosil; Subiono, Subiono; Imron, Chairul; Herisman, Iis; Usadha, I Gst Ngr Rai; Soleha, Soleha; Mufid, Muhammad Syifa'ul
Sewagati Vol 9 No 1 (2025)
Publisher : Pusat Publikasi ITS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j26139960.v9i1.2257

Abstract

Pelatihan yang diadakan untuk guru matematika dan siswa SMA di Yayasan Pendidikan Pesantren Zainul Hasan Genggong (PPZHG) bertujuan memperdalam pemahaman konsep-konsep mata pelajaran Matematika, dengan fokus khusus pada bagaimana guru dan siswa mampu menyelesaikan soal-soal Olimpiade Sains Kabupaten (OSK) di bidang Matematika dan Informatika. Program pelatihan ini dilaksanakan secara luring sesuai dengan jadwal yang telah disusun oleh yayasan. Hasil pelatihan menunjukkan bahwa 1) para guru mampu menyalurkan materi yang mereka terima kepada murid-muridnya, dan 2) siswa yang mengikuti pelatihan dapat berbagi ilmu dengan teman sebayanya serta adik-adik kelas mereka. Sasaran utama dari kegiatan ini adalah meningkatkan kemampuan peserta dalam menyelesaikan soal-soal OSK Matematika dan Informatika, yang ditunjukkan melalui hasil post-test yang lebih baik dibandingkan dengan pre-test.
Rancang Bangun Oil Spinner Sebagai Peniris Minyak Goreng Otomatis Terintegrasi Panel Surya Dalam Meningkatkan Kualitas Produk Kerupuk Pada UMKM Toko Lestari Lokasi : (Kenjeran Bulak, Surabaya, Jawa Timur) Musyafa, Ali; Abadi, Imam; Harsono, Harsono; Asyari, Muhammad Khamim; Imron, Chairul; Raafi’u, Brian; Ashiddiqi, Muhammad Roy; Rahmadiansah, Andi; Oktavia, Yunaini Istivani; Hudaningrum, Laila Puji; Setianingtias, Regina Putri; Norhalimah, Norhalimah
Sewagati Vol 9 No 3 (2025)
Publisher : Pusat Publikasi ITS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j26139960.v9i3.2404

Abstract

Kandungan minyak berlebih pada produk kerupuk dapat menurunkan kualitas, mempercepat ketengikan, dan mengurangi daya simpan. Penelitian ini bertujuan untuk merancang dan membangun oil spinner otomatis yang terintegrasi dengan panel surya sebagai sumber energi guna mengurangi kadar minyak goreng pada kerupuk, sehingga meningkatkan kualitas produk secara keseluruhan. Metode yang digunakan meliputi tahap perancangan, pembuatan, pengujian alat, dan implementasi. Sistem ini terdiri dari komponen utama berupa motor pemutar, wadah berputar, dan panel surya sebagai sumber daya utama. Pengujian dilakukan dengan membandingkan kadar minyak sebelum dan sesudah proses penirisan pada berbagai kecepatan putaran. Hasil penelitian menunjukkan bahwa alat ini mampu mengurangi kadar minyak yang teruji dapat berputar dengan kecepatan maksimum sebesar 829,3 rpm dengan minyak yang tertiris sebesar 9,8 mL dalam satu kali proses penirisan. Alat ini memanfaatkan energi surya sehingga lebih hemat energi dan ramah lingkungan dengan kapasitas 150 Wp, baterai dengan kapasitas 12 Volt 100 Ah, dan inverter dengan daya sebesar 300 Watt. Pengembangan lebih lanjut dapat difokuskan pada peningkatan efisiensi sistem tenaga surya dan otomatisasi proses agar lebih optimal dalam skala industri.
MAGNETOHYDRODYNAMICS NANOFERRO FLUID FLOWS PASSING THROUGH A MAGNETIC POROUS SPHERE UNDER THERMAL RADIATION EFFECT Widodo, Basuki; Pamela, Eirene Juwita Ningtyas; Adzkiya, Dieky; Imron, Chairul; Rahayuningsih, Tri
BAREKENG: Jurnal Ilmu Matematika dan Terapan Vol 16 No 4 (2022): BAREKENG: Journal of Mathematics and Its Applications
Publisher : PATTIMURA UNIVERSITY

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (456.749 KB) | DOI: 10.30598/barekengvol16iss4pp1303-1312

Abstract

In the application of thermonuclear reactor cooling, temperature regulation relies on experiments based on practical experience. Therefore, the accuracy of this temperature setting is operator-dependent. So it is necessary to develop a mathematical model to solve these problems. The dimensional mathematical model therefore is generated using the conservation laws of mass, momentum, and energy. The dimensional mathematical model is further transformed into non-dimensional mathematical model by using non-dimensional variables. The non-dimensional mathematical model is simplified using the similarity equation by utilizing the stream function. The model obtained is a system of nonlinear ordinary differential equations. This system of equations is then solved using an implicit numerical method using Keller-Box scheme. This Keller-Box method has high accuracy and is more efficient. The numerical simulation results show that the velocity profile and temperature profile decrease as the magnetic parameter, porosity parameter, and the Prandtl number increases, respectively. Meanwhile, when the radiation parameter increases, the temperature profile also increases, but the radiation parameter does not affect the velocity profile.
ANALYSIS AND OPTIMAL CONTROL OF HIV GROWTH MODEL IN THE BODY WITH ANTIRETROVIRAL THERAPY Damayanti, Erlyana Trie; Imron, Chairul
BAREKENG: Jurnal Ilmu Matematika dan Terapan Vol 18 No 2 (2024): BAREKENG: Journal of Mathematics and Its Application
Publisher : PATTIMURA UNIVERSITY

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30598/barekengvol18iss2pp1179-1188

Abstract

Human Immunodeficiency Virus (HIV) is a virus that affects the human immune system. HIV infection causes a decrease in the body's immunity because the virus attacks immune-building cells, especially T-CD4 cells. Currently, there is no treatment that can cure or eliminate HIV, but antiretroviral therapy can be done. This study discusses the growth model of HIV in the body that is given control in an effort to maximize healthy T-CD4 cells. In this model, the infection-free and infected equilibrium points are also discussed and their stability is analyzed. Then the optimal control is solved using the Pontryagin Maximum Principle method and solved numerically using the fourth-order Runge Kutta method. Based on the analysis and simulation results, the system is asymptotically stable around the infection-free equilibrium point and unstable around the infected equilibrium point. Simulation results show that with the control of antiretroviral therapy, the T-CD4 cell population grows significantly which can improve the quality of life of patients. And the growth of HIV in the body can be inhibited until it cannot reproduce itself.
ANALYSIS AND OPTIMAL CONTROL OF TUBERCULOSIS DISEASE SPREAD MODEL WITH VACCINATION AND CASE FINDING CONTROL (CASE STUDY: SURABAYA CITY) Maulina, Dinda Anisa'; Imron, Chairul
BAREKENG: Jurnal Ilmu Matematika dan Terapan Vol 18 No 2 (2024): BAREKENG: Journal of Mathematics and Its Application
Publisher : PATTIMURA UNIVERSITY

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30598/barekengvol18iss2pp1189-1200

Abstract

Tuberculosis is a contagious disease that infects humans. It is caused by the bacterium Mycobacterium tuberculosis (M.tb). It is the largest infectious disease in the world and has become a major global health problem. Therefore, efforts are being made to control the spread of tuberculosis disease through vaccination and case finding, with the aim of reducing the population of latently infected and actively infected individuals. This study discusses the mathematical model of tuberculosis disease spread, disease-free and endemic equilibrium points, and stability analysis around the equilibrium points. Then, using Pontryagin's minimum principle, the optimal control problem is solved numerically by the 4th-order Runge-Kutta method. Based on the analysis and simulation results, the system is asymptotically stable around the disease-free and endemic equilibrium points. Furthermore, optimal control in the form of vaccination of susceptible individuals is required to further suppress the rate of change of susceptible individuals into latent individuals, while control in the form of case finding on latently infected individuals is required until the 9th year to minimize the population size, while on actively infected individuals, it is required until the 8th year to minimize the population size. Providing optimal control resulted in a 100% increase in the susceptible population and a 100% reduction in the latent and infected populations.
Co-Authors Ahlan Hamami Ali Musyafa Andi Rahmadiansah Ashiddiqi, Muhammad Roy Asyari, Muhammad Khamim Basuki Basuki Basuki Widodo Basuki Widodo Damayanti, Erlyana Trie Dieky Adzkiya Eko Krisdiono Erna Apriliani Fahim, Kistosil Hakam, Amirul Harsono Harsono Hesti Hastuti Hudaningrum, Laila Puji Iis Herisman Imam Abadi Jason Otniel Dharmanta Maulina, Dinda Anisa' Mufid, Muhammad Syifa'ul Mufid, Muhammad Syifa’ul Norhalimah, Norhalimah Oktavia, Yunaini Istivani Pamela, Eirene Juwita Ningtyas Raafi’u, Brian Rina Sahaya Ruli Yuda Baha'ullah Setianingtias, Regina Putri Soleha Soleha Soleha Subiono Subiono - Suhud Wahyudi Tahiyatul Asfihani Tri Rahayuningsih Triyogi Yuwono Triyogi Yuwono Usadha, I Gst Ngr Rai Yunus, Mahmud