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All Journal International Journal of Electrical and Computer Engineering Reaktor BERKALA FISIKA SAINS DAN MATEMATIKA JURNAL SISTEM INFORMASI BISNIS Jurnal Sains Materi Indonesia YOUNGSTER PHYSICS JOURNAL Scientific Journal of Informatics Register: Jurnal Ilmiah Teknologi Sistem Informasi Journal of Physics and Its Applications

Vincensius Gunawan S.K.

Jurusan Fisika, Fakultas Sains Dan Matematika, Universitas Diponegoro, Semarang

Author-ID : 271037

Astronomy Chemical Engineering, Chemistry & Bioengineering Computer Science & IT Control & Systems Engineering Earth & Planetary Sciences Economics, Econometrics & Finance Electrical & Electronics Engineering Energy Materials Science & Nanotechnology Mathematics Physics

Published : 17 Documents Claim Missing Document

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Hysteresis Loops for Magnetoelectric Multiferroics Using Landau-Khalatnikov Theory Vincensius Gunawan; Ngurah Ayu Ketut Umiati
International Journal of Electrical and Computer Engineering (IJECE) Vol 8, No 6: December 2018
Publisher : Institute of Advanced Engineering and Science

We present a theoretical discussion of the hysteresis in magnetoelectric multiferroics with bi-quadratic magnetoelectric coupling. The calculations were performed by employing Landau-Khalatnikov equation of motion for both the ferroelectric and ferromagnetic phase, then solve it simultaneously. In magnetoelectric, we obtain four types of hysteresis: ferroelectric hysteresis, ferromagnetic hysteresis and two types of cross hysteresis (electric field versus magnetization and magnetic field versus electric polarization). The cross hysteresis has butterfly shape which agree with the result from the previous research. It can also be seen from that hysteresis, that magnetization / electric polarization can not be flipped into the opposite direction using external electric / magnetic field when the magnetoelectric coupling is bi-quadratic type. Overall, the result shows that Landau-Khalatnikov equation is able to approximate hysteresis loops in multiferroics system.

KAJIAN TEORETIS RAGAM POLARITON MAGNETIK DALAM BAHAN LOGAM ANTIFEROMAGNET Vincensius Gunawan S. K.; Kamsul Abraha
Jurnal Sains Materi Indonesia Vol 5, No 1: OKTOBER 2003
Publisher : Center for Science & Technology of Advanced Materials - National Nuclear Energy Agency

KAJIAN TEORETIS RAGAM POLARITON MAGNETIK DALAM BAHAN LOGAM ANTIFEROMAGNET. Telah dilakukan penelitian untuk menurunkan relasi dispersi polariton magnetik dalam bahan logam antiferomagnet dengan geometri semi tak-hingga. Bahan dibuat beralur (berlapis) dengan bahan isolator nonmagnet agar efek penyekatan berkurang sehingga ragam polariton dapat dibangkitkan. Diperoleh hasil relasi dispersi ragam polariton permukaan yang bersifat berbalik, ω (kx) = ω(-kx) (tanpa keberadaan medan magnet luar. Bila medan magnet luar diterapkan, ragam polariton pennukaan menunjukkan sifat tak berbalik, ω (kx) ≠ ω(-kx). Daya hantar bahan magnet menyebabkan timbulnya redaman dalam ragam polariton. Redaman cenderung semakin besar seiring dengan diterapkannya medan luar.

Synthesis of Titanium Dioxide (TiO2) Fine particle by Flame Spray Pyrolysis (FSP) Method using Liquid Petroleum Gas (LPG) as Fuel Hendri Widiyandari; Agus Purwanto; Vincensius Gunawan; Susilo Adi Widyanto
Reaktor Volume 17 No. 4 Desember 2017
Publisher : Dept. of Chemical Engineering, Diponegoro University

This study aims to obtain titanium dioxide (TiO2) fine particle with a narrow size distribution by one step production via flame spray pyrolysis (FSP) using LPG (liquid petroleum gas) as a fuel source. The TiO2 particles were synthesized from the aqueous based precursor from dissolving of titanium (IV) isopropoxide to the acidic distilled water solvent. The effect of precursor concentration to the crystalline structure, morphology and size distribution of the TiO2 particles were systematically investigated. There were observed that the TiO2 has a uniform spherical shape with particle size around 200 – 500 nm. Increasing the precursor concentration resulted the size distribution shifted toward the bigger size. The crystalline structure of produced TiO2 showed the mixed phase of anatase and rutile and has a large specific surface area ~ 850,343 m²/g.

KOREKSI KURVA ISODOSIS 2D UNTUK JARINGAN NONHOMOGEN MENGGUNAKAN METODE TAR (TISSUE AIR RATIO) Ryan Kurniawan; Vincensius Gunawan; Choirul Anam
Youngster Physics Journal Vol 3, No 4 (2014): Youngster Physics Journal Oktober 2014
Publisher : Jurusan Fisika, Fakultas Sains dan Matematika, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (229.613 KB)

Treatment Planning System (TPS) are used to determine the dosedistribution to be received before the irradiation in patients. To see how much radiation dose to be received on the target volume and surrounding critical organs that are required isodose curve. 2D isodose curves correction on non-homogeneous tissues done because in fact the human body not only in the form of soft tissue, but there are also other tissues such as bone tissue or lung. Isodose curve correction have been made using Tissue Air Ratio (TAR) method with Matlab software on a wide field of 10 x 10 cm2. Correction factor is obtained by comparing the effective depth of the TAR with TAR at each depth. Correction factor multiplied by the curve isodose for homogeneous phantom have been obtained from Percentage Depth Dose (PDD) and dose profiles. Corrected isodose curves obtained for nonhomogeneous phantom. Higher the density value on nonhomogeneous phantom, the attenuation will increase and produce the lower dose. Keywords: Treatment Planning System (TPS), 2D Isodose curve, Tissue Air Ratio (TAR), Correction factor, nonhomogeneous tissue, attenuation

PEMBUATAN KURVA ISODOSIS 2D UNTUK BERKAS ELEKTRON ENERGI 5 MeV MENGGUNAKAN PROFILE DOSE DAN KURVA PERCENTAGE DEPTH DOSE (PDD) UNTUK TREATMENT PLANNING SYSTEM RADIOTERAPI Mahfudz Fauzan; Vincensius Gunawan; Choirul Anam
Youngster Physics Journal Vol 4, No 1 (2015): Youngster Physics Journal Januari 2015
Publisher : Jurusan Fisika, Fakultas Sains dan Matematika, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (405.037 KB)

Research has been done to make isodose curve of electron beam with the energy of 5 MeV. Isodosis curve performed using PDD curves and dose on broad Profile 10x10 cm2 field; 15x15 cm2; 20x20 cm2; 25x25 cm2, with a depth of 0.5 cm; 1.0 cm; 1.5 cm; 2.0 cm; 2.5 cm. The purpose of this study was to obtain 2D isodose curve shape can be applied to TPS in Radioteraphy.The method which was used to form the isodose curve using PDD curves and dose profiles was done by equalizing the data at each depth using interpolation techniques at intervals of 0.25 cm and normalized to a value of 1, and calculatd the dose at each pixel using the weighting technique that formed isodosis curve with the distribution each depth and broad field. The results show that the PDD curve formed using the interpolation does not affect the magnitude of the dose at different field wide, profile shaped dose showed a dose level at each different depth and normalized to a value of 1 to show the dose at the surface, the isodose curve formation can be applied to compare the isodose curve formed by TPS in Radiotherapy. Keywords: Radiotherapy, Treatment Planning System (TPS), isodose curve, Percentage Depth Dose (PDD), Profile dose

The Electric Susceptibility of Bi-Layers Ferroelectrics Vincensius Gunawan; Ngurah Ayu Ketut Umiati; Agus Subagio
Journal of Physics and Its Applications Vol 1, No 2 (2019): May 2019
Publisher : Diponegoro University Semarang Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/jpa.v1i2.4860

In order to enhance insight of layered structure, we perform numerical calculation to obtain the dynamic electric susceptibility in bi-layers ferroelectrics. Since susceptibility is a parameter which gives response to the external field, then determination of this parameter is important. A lattice model is employed to slice bilayer structure into several lattices. Then, Landau-Khalatnikov equation of motion is used in each lattice to construct a matrix equation of equation of motion. The solution is obtained by applying entire-cell effective medium. We find that the homogeneity of dynamic polarization is different from homogeneity of the single individual layer due to the existence of interlayer interaction. As a result, the electric susceptibility is also altered. It is also noticed that there is a relation between the homogeneity of dynamic polarization and the value of electric susceptibility near resonant frequency. The higher the homogeneity, the bigger the values of susceptibility will be.

Pengukuran Tingkat Risiko dan Keamanan Informasi Menggunakan Metode FMEA Berbasis ISO/IEC 27001 pada Instansi XYZ untuk Keamanan Sistem Informasi Kusnandar, Aris; Rochim, Adian Fatchur; Gunawan, Vincensius
Jurnal Sistem Informasi Bisnis Vol 14, No 4 (2024): Volume 14 Nomor 4 Tahun 2024
Publisher : Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21456/vol14iss4pp375-384

The more information stored in an organization, the higher the risks that may arise, such as damage, loss, or the exposure of personal information to irresponsible parties. XYZ Institution faces information security threats from various sources, including data theft, damage, and computer hacking. It is essential for the organization to understand the level of information security risk to ensure information remains secure. Therefore, this study proposes measuring information security risk using the FMEA method and analyzing information security risks based on ISO/IEC 27001:2013. The aim of this study is to identify and assess the level of information security risk at XYZ Institution to provide recommendations for information security. The study's results revealed 4 high-risk information security threats, 9 medium-risk threats, and 16 low-risk threats. The findings demonstrate that the organization needs to pay more attention to information security to ensure its smooth operation in the future.

Co-Authors Abd. Rasyid Syamsuri Adian Fatchur Rochim Agung Cahyono Agus Purwanto Agus Subagio Aris Kusnandar Asfan Muqtadir Choirul Anam AM Diponegoro Dewi Tri Nugraheni, Dewi Tri Farhatin Nurul Ihya Hendri Widiyandari Indras Marhaendrajaya Ircham Ali Kamsul Abraha Kusworo Adi Mahfudz Fauzan Ngurah Ayu Ketut Umiati Priyono Priyono Rachmad Gernowo Robert L Stamps Ryan Kurniawan Singgih Sugiarto, Singgih Suryono Suryono Susilo Adi Widyanto

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