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The Bilinear Formula in Soliton Theory of Optical Fibers Nando Saputra; Ahmad Ripai; Zulfi Abdullah
Jurnal Fisika Unand Vol 11 No 3 (2022)
Publisher : Universitas Andalas

Solitons are wave phenomena or pulses that can maintain their shape stability when propagating in a medium. In optical fibers, they become general solutions of the Non-Linear SchrÃ¶dinger Equation (NLSE). Despite its mathematical complexity, NLSE has been an interesting issue. Soliton analysis and mathematical techniques to solve problems of the equation keep doing. Yan & Chen (2022) introduced them based on bilinear formula for the case of the generalized NLSE extended models into third and fourth-order dispersions and cubic-quintic nonlinearity. In this paper, we review the form of the bilinear formula for the case. We re-observed a one-soliton solution based on the formula and verified the work of the last researcher. Here, the mathematical parameters of position Î±(0) and phase Î· are verified to become features of change in horizontal position and phase of one soliton in the (z, t) plane during propagation. In addition, we notice the soliton has established stability. Finally, for the condition Kerr effect focusing or the group velocity dispersion Î²2 more dominates, we present like the soliton trains in optical fibers under modulation instability of plane wave.

An Exact Solution of Nonlinear Schrödinger Equation in a Lossy Fiber System Using Direct Solution Method Zulfi Abdullah; Trengginas Eka Putra Sutantyo; Mahdhivan Syafwan; Ahmad Ripai; Hanifah Azzaura Musyayyadah; Mohamad Nazri Abdul Halif
Jurnal Ilmu Fisika Vol 15 No 1 (2023): March 2023
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jif.15.1.13-21.2023

We present an exact solution of the nonlinear Schrödinger equation (NLSE) for beam propagation in nonlinear fiber optics. It is a lossy fiber system with the beam as solitons. Fiber losses are understood to reduce the peak power of solitons along the fiber length. That is due to its value depending on the fiber attenuation constant of α. Considering fiber loss features on the equation, we write one set modification of the NLSE and make models the main topic of our work. We solved the model and found a straightforward analytical solution of modified NLSE for the system via the direct solution method. To the best of our knowledge, no literature has presented such as solution yet. By substituting them into equations, we validate solutions. It is valid as an exact solution to the NLSE. Lastly, we found a solution offering soliton propagation suitable for the system under study.

Enhancement of Light Absorption in the Active Layer of Organic Solar Cells using Ag:SiO2 Core-Shell Nanoparticles Fahendri Fahendri; Ilham Perdana; Zulfi Abdullah; Mulda Muldarisnur
Jurnal Penelitian Pendidikan IPA Vol 8 No 6 (2022): December
Publisher : Postgraduate, University of Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29303/jppipa.v8i6.2393

Organic solar cells still suffer from relatively low conversion efficiency despite significant progress. An Ag:SiO2 core-shell nanoparticle embedded inside the active layer of an organic solar cell is expected to enhance light absorption. Light absorption within the active layer consisting of 70 nm thickness PEDOT: PSS and P3HT: PCBM was calculated using the finite element method for a variable diameter of the silver core, the thickness of the SiO2 shell, and the relative position of nanoparticle inside the active layer. The diameter of the Ag nanoparticle varies from 20 to 50 nm, the thickness of SiO2 varies from 1 to 4 nm, and the position was shifted vertically to 70 nm. The maximum light absorption in the active layer is obtained for silver nanoparticles with a diameter of 40 nm and a SiO2 thickness of 1 nm. The optimum position of the core-shell nanoparticle was found to be not at the interface between the PEDOT: PSS and P3HT: PCBM layers but a little bit shifted down into P3HT: PCBM layer. The highest increase of light absorption, compared to without Ag:SiO2, is 210%, much higher than reported in the literature. Increasing absorption is related to the excitation of surface plasmon resonance of Ag:SiO2 nanoparticles leading to the local field and scattering enhancement in the active layer of the organic solar cell

Light absorption enhancement in organic solar cell using non-concentric Ag:SiO2 core-shell nanoparticles Muldarisnur, Mulda; Fahendri, F.; Perdana, Ilham; Abdullah, Zulfi; Yusfi, Meqorry
Communications in Science and Technology Vol 8 No 1 (2023)
Publisher : Komunitas Ilmuwan dan Profesional Muslim Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21924/cst.8.1.2023.1076

Low solar energy conversion efficiency prevents the widespread of organic solar cells; hence, metal nanoparticles have been used to overcome this problem without increasing cell thickness. We investigated light absorption enhancement in view of the embedment of Ag:SiO2 core-shell nanoparticles of different shell thicknesses, core offsets, offset orientation angles, and vertical mismatches between neighboring particles. The simulations were carried out using the finite element method. This is the first investigation in the use of asymmetric nanoparticles. At optimized conditions, absorption enhancement up to 345% compared to the one without the nanoparticles could be achieved. The enhancement was found much higher than that of the published values. The enhancement results were mainly from the increase of near-field localization and scattering in the active layer of solar cells due to the excitation of Fano resonances. The resonance occurred due to the non-symmetric nature of the core-shell nanoparticles.

Efficiency at Maximum Power of Endoreversible Quantum Otto Engine with Partial Thermalization in 3D Harmonic Potential Zettira, Zahara; Sutantyo, Trengginas Eka Putra; Abdullah, Zulfi
Jurnal Ilmu Fisika Vol 16 No 1 (2024): March 2024
Publisher : Jurusan Fisika FMIPA Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jif.16.1.22-33.2024

We study the partial thermalization to the effect of efficiency at maximum power (EMP) of a quantum Otto engine using Bose-Einstein Condensation in 3D harmonic potential. Partial thermalization occurs at a finite-time isochoric process, preventing the medium from achieving equilibrium with reservoirs, leaving it in a state of residual coherence. Under these circumstances, the performance of the engine can be seen from its power and EMP. The 3D harmonic potential is used to generate an excitation of energy during the expansion and compression. The total energy is defined by the total work done in a cycle. Using Fourier’s law in conduction, we found that power explicitly depends on the duration of heating and cooling stroke time and efficiency of the engine; that is the higher stroke time and efficiency, the less power output. In order to find EMP, we maximize power with respect to compression ratio κ, and we found that EMP also depends on the isochoric heating and cooling process. By varying the stroke time of the isochoric process, EMP slightly decreases with increasing isochoric time due to entropy production. However, adjusting cooling stroke time more extended than heating stroke time could significantly improve the EMP of Otto Engine.

Efficiency at Maximum Power of Endoreversible Quantum Otto Engine with Partial Thermalization in 3D Harmonic Potential Zettira, Zahara; Sutantyo, Trengginas Eka Putra; Abdullah, Zulfi
Jurnal Ilmu Fisika Vol 16 No 1 (2024): March 2024
Publisher : Jurusan Fisika FMIPA Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jif.16.1.22-33.2024

We study the partial thermalization to the effect of efficiency at maximum power (EMP) of a quantum Otto engine using Bose-Einstein Condensation in 3D harmonic potential. Partial thermalization occurs at a finite-time isochoric process, preventing the medium from achieving equilibrium with reservoirs, leaving it in a state of residual coherence. Under these circumstances, the performance of the engine can be seen from its power and EMP. The 3D harmonic potential is used to generate an excitation of energy during the expansion and compression. The total energy is defined by the total work done in a cycle. Using Fourier’s law in conduction, we found that power explicitly depends on the duration of heating and cooling stroke time and efficiency of the engine; that is the higher stroke time and efficiency, the less power output. In order to find EMP, we maximize power with respect to compression ratio κ, and we found that EMP also depends on the isochoric heating and cooling process. By varying the stroke time of the isochoric process, EMP slightly decreases with increasing isochoric time due to entropy production. However, adjusting cooling stroke time more extended than heating stroke time could significantly improve the EMP of Otto Engine.

TEKNIK PEMISAHAN OPERATOR DAN PENDEKATAN SPEKTRAL SEBAGAI SOLUSI PERSAMAAN SCHRÃ–DINGER BERGANTUNG WAKTU PADA ATOM HIDROGEN Azis, Salman Abdul; Abdullah, Zulfi
Jurnal Fisika Unand Vol 4 No 3: Juli 2015
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jfu.4.3.%p.2015

ABSTRAKTelah Â dikembangkan sebuah metode numerik dengan teknik pemisahan operator dan pendekatan oleh fungsi basis spektral (Sorevik dkk., 2009) untuk menyelesaikan persamaan SchrÃ¶dinger bergantung waktu pada koordinat bola. Penelitian Sorevik dkk. mendefinisikan fungsi gelombang tereduksi, teknik splitting Strang, metode kolokasi Chebyshev, variabel transformasi di arah radial, rumus umum metode swadekomposisi pada swanilai di arah radial, swanilai fungsi basis harmonik bola, dan teknik memulihkan fungsi basis Chebyshev. Sedangkan, penelitian ini memberikan analisis fisis dan matematis untuk menjabarkan metode ini disertai penerapannya pada sistem atom hidrogen. Hasil penelitian ini melengkapi penelitian Sorevik dkk. dalam memberikan seluruh tafsiran dan penyusunan persamaan numerik meliputi nilai inisialisasi swafungsi, diskritisasi fungsi Chebyshev dan polinomial Legendre terasosiasi yang dinormalisasi, ortogonalitas koefisien fungsi basis Chebyshev dan harmonik bola, transformasi Householder dan Metode QR untuk menghitung swanilai operator di arah radial, dan propagasi waktu imajiner.Kata kunci : persamaan SchrÃ¶dinger bergantung waktu, model atom kuantum, teknik pemisahan operator, pendekatan spektral, atom hidrogenAbstractIt has been developed a numerical method with operator-splitting technique and spectral approximation by spectral basis functions (Sorevik et al., 2009) to solve the time-dependent SchrÃ¶dinger equation on spherical coordinates. Sorevik et al.â€™s research defines the reduced wave function, Strang splitting technique, Chebyshev collocation method, variable transformation in the radial direction, the general formula of eigen decomposition method on eigen values in the radial direction, eigen values of spherical harmonic basis function, and a technique to restore the Chebyshev basis function. While this study provides physical and mathematical analysis to describe this method with its application in hydrogen atom system. This study complements the results of research Sorevik et al in giving the whole interpretation and compilation of numerical equations include initialization value of eigen function, discretization Chebyshev function and normalized associated Legendre polynomial, orthogonality coefficient of Chebyshev and spherical harmonic basis functions, Householder transformation and QR method for calculating eigen values of operator in the radial direction, and the propagation of imaginary time.Keywords : the time dependent SchrÃ¶dinger equation, quantum atomic model, splitting-operator technique, spectral approximation, hydrogen atom

Evolusi Soliton pada Model Frenkel-Kontorova yang Tereduksi ke Persamaan Sine-Gordon Melalui Pendekatan Limit Kontinu Angga, Boy; Abdullah, Zulfi; Shafwan, Mahdhivan
Jurnal Fisika Unand Vol 5 No 2 (2016)
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jfu.5.2.153-158.2016

Model Frenkel-Kontorova telah direduksi ke persamaan Sine-Gordon melalui pendekatan limit kontinu.Â Solusi persamaan Sine-Gordon diselesaikan menggunakan transformasi Baecklund dan didapatkan 3Â soliton yaitu kink, antikink dan breather. Akan tetapi, transformasi BÃ¤cklund tidak dapat memberikanÂ gambaran bagaimana evolusi soliton yaitu dari keadaan soliton-like menuju ke keadaan steady. MetodeÂ yang digunakan untuk menerangkan evolusi soliton adalah aproksimasi dengan memanfaatkan teoremaÂ Noether (konsep energi konservatif). Hasil menunjukkan bahwa keadaan solitonlike selalu tidak stabilselama proses evolusi berlangsung.Kata Kunci: evolusi soliton, limit kontinu, model Frenkel-Kontorova, persamaan Sine-Gordon, soliton,Â soliton-like, teorema Noether.

Implementasi Jaringan Syaraf Tiruan Backpropagation untuk Deteksi Penyakit Tuberculosis (TB) Paru dari Citra Rontgen Depinta, Ledyva; Abdullah, Zulfi
Jurnal Fisika Unand Vol 6 No 1 (2017)
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jfu.6.1.61-66.2017

Telah dilakukan implementasi Jaringan Syaraf Tiruan (JST) Backpropagation untuk deteksi penyakit tuberculosis (TB) paru dari citra rontgen. Input yang digunakan untuk pelatihan JST adalah citra foto rontgen paru-paru yang terdiri dari TB paru dan paru-paru normal. Proses ini diawali dengan pengolahan citra yaitu cropping, resizing, median filtering, BW Labelling dan ekstraksi fitur menggunakan wavelet haar untuk melakukan pengenalan pola penyakit TB paru. Ekstraksi fitur citra foto rontgen menggunakan fitur energi dan koefisien setiap subband yang kemudian dimasukkan ke jaringan syaraf tiruan. Pengenalan pola yang dapat dilakukan oleh JST pada penelitian ini adalah pola sebaran warna hitam dan putih dari citra rontgen yang telah melewati proses wavelet haar. Parameter yang digunakan yaitu dengan 3 hidden layer, 1 output, learning rate 0,7 dan target error 1000. Hasil pengujian JST backpropagation untuk deteksi penyakit TB paru diperoleh akurasi 79,41% dalam mendeteksi keabnormalan dari citra foto rontgen paru.Â Kata kunci : Jaringan syaraf tiruan backpropagation, foto rontgen, TB paru

Analisis Percepatan Tanah Gempa di Sumatera Menggunakan Jaringan Syaraf Tiruan Metode Backpropagation Widianto, Toni; Abdullah, Zulfi; Pujiastuti, Dwi
Jurnal Fisika Unand Vol 8 No 1 (2019)
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jfu.8.1.64-71.2019

Telah dilakukan penelitian tentang percepatan tanah menggunakan Jaringan Syaraf Tiruan (JST) yang bertujuan untuk menganalisis serta memprediksi percepatan tanah di Sumatera. Penelitian inimenggunakan data percepatan tanah yang direkam dengan accelerograph yang terdapat pada 3 stasiun di Sumatera Barat, yaitu Stasiun Geofisika Padang Panjang (PAPA), Stasiun Meteorologi Ketaping (PATA), dan Stasiun Maritim Teluk Bayur (PATU). Pengolahan data ini menggunakan metode backpropagation. Dalam pengolahan data, dilakukan dengan 2 jenis pembagian data, yaitu pembagian data dengan rasio 50:50, dimana data tahun 2016 dan 2017 digunakan sebagai target uji, selanjutnya pembagian dengan rasio 80:20, dimana data tahun 2017 digunakan sebagai target uji. Setelah dilakukan proses pelatihan dan pengujian, didapatkan bahwa pembagian data dengan rasio 80:20 mendapatkan hasil yang lebih baik daripada pembagian data dengan rasio 50:50. Secara keseluruhan pada proses pengolahan data yang telah dilakukan, dapat disimpulkan bahwa JST tidak mampu memprediksi percepatan tanah di Sumatera, hal ini dikarenakan nilai error yang didapatkan cukup besar.Kata kunci: percepatan tanah, jaringan syaraf tiruan, backpropagation

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