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All Journal BERKALA FISIKA Jurnal Matematika & Sains Journal of Medical Physics and Biophysics Makara Journal of Science Indonesian Journal of Physics (IJP) Wahana Fisika : Jurnal Fisika dan Terapannya

Idam Arif

Institut Teknologi Bandung

Author-ID : 285058

Astronomy Computer Science & IT Earth & Planetary Sciences Electrical & Electronics Engineering Energy Engineering Materials Science & Nanotechnology Mathematics Medicine & Pharmacology Physics

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Articles

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Lattice-Gas Automata for Numerical Experimental Verification of Maxwell-Boltzmann Distribution Siti Nurul Khotimah; Idam Arif; The Houw Liong
Indonesian Journal of Physics Vol 12 No 3 (2001): Vol. 12 No.3, Juli 2001
Publisher : Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (84.87 KB)

Lattice-gas automata model has been applied to simulate the distribution function of gas molecules. This study shows a transition of a single-component velocity distribution from its initial non-equilibrium to its final equilibrium. The distribution is independent of time when the system reaches its equilibrium. For a sufficiently dilute gas in equilibrium, the distribution function of x-velocity component is a Maxwell-Boltzmann distribution with its average velocity component is between zero and 3% of its maximum value. This numerical experiment also obtained that the speed distribution for two-dimensional problem is a Maxwell-Boltzmann distribution. From 12 trials, average and root mean square speeds are (8.6±0.3) and (9.7±0.3) lattice units per time step respectively. We introduce a factor β to converse the unit of speed to be in meter per second. Therefore, the absolute temperature (in Kelvin) of the experiment is expressed in the mass of one molecule and Boltzmann constant as (47,1±3,2)β2 m/k.

Study on Annual Internal Radiation Dose from Consumption of Sweet Potatoes Contaminated by 134 Cs Idam Arif; Siti Nurul Khotimah; Octolia Tobigasa Tambunan; Poppy Intan Tjahaja
Indonesian Journal of Physics Vol 21 No 1 (2010): Vol. 21 No. 1, January 2010
Publisher : Institut Teknologi Bandung

The transfer of 134Cs from soil to sweet potato crops has been investigated. Sweet potato crops were cultivated in soil contaminated by 134Cs with concentration of 167.62 Bq/g as well as in non-contaminated soil as control. The 134Cs activity concentrations of leaves, stems, roots, tubers and the whole plant were determined every week up to 16 weeks. 134Cs activity concentrations of soil in root zone and outside root zone were also determined. The maximum transfer factor for the whole sweet potato plants takes place at the second week with TF value of 1.277. The maximum TF value for each parts are roots (18.448), tubbers (13.153), stems (1.241), and leaves (0.746). Annual equivalent dose was calculated based on the activity of sweet potato plants at harvest time. This research obtained annual internal radiation dose from consumption of sweet potatoes contaminated by 134Cs of 0.0185 mSv/year. This value compared with average annual dose limits recommended by BAPETEN, IAEA and ICRP respectively was 0.14%, 0.37%, and 0.19%.

Calculation Procedure for Dynamic Condition of Ion Composition in Cell Walls Altered by Proton Fluxes Idam Arif
Indonesian Journal of Physics Vol 22 No 3 (2011): Vol. 22 No. 3, July 2011
Publisher : Institut Teknologi Bandung

The calculation procedure has been developed to determine the dynamic condition of the ion composition in cell walls during proton extrusion, known as the Weak Acid Donnan Manning (WADM) model for fluxes. In this model, the walls of plant cells are considered as a system containing weak acid polymers where the interaction of ions obeys the Manning condensation theory and the Donnan theory. When protons are transported across the walls during proton fluxes, the transported proton will interact with the wall ions and alter the ion composition. This depends on the wall parameters such as the concentration of ionisable sites, the pK of the wall weak acid, and the wall linear charge density parameter. When the linear charge density parameter is still higher than the reciprocal of the highest valence of the involve cations, the transported protons during proton fluxes will decrease the wall pH, alter the ion composition in the wall Donnan free space and water free space, and release the condensed cations. Therefore some of the proton fluxes are represented by the flux of the condensed cations outside the walls. However when the linear charge density parameter is less than the reciprocal of the highest valence of the involve cations, there is no condensed cations in the walls so that the transported protons only alter the ion composition in the wall Donnan free space and water free space.

Permeability and Porosity of Two-Dimensional Porous Media Microchannels using Lattice Gas Cellular Automata Siti Nurul Khotimah; Bergas Bimo Branarto; Sparisoma Viridi; Idam Arif
Indonesian Journal of Physics Vol 23 No 1 (2012): Vol. 23 No. 1, July 2012
Publisher : Institut Teknologi Bandung

In this study, lattice-gas cellular automata were used to solve the flow of incompressible Newtonian-fluid in porous media microchannels. We discuss fluid flow between two stationary parallel plates. By applying a constant pressure gradient, volumetric flux was determined as a function of time until a steady condition is achieved. For steady laminar flow, its velocity profile is parabolic. For flow in porous media between two stationary parallel plates, the results show that medium permeability depends on porosity and obstacle configurations. For a single obstacle, the permeability is a parabolic function with respect to positions of an obstacle in the direction perpendicular to the flow. The permeability is smallest when the obstacle is at the central line along the flow. A maximum permeability may be achieved when the obstacles attached to the channel wall. Other obstacle structures give lower permeability, even zero permeability for dead end microchannels.

Multiclass Classification of Covid-19 CT Scan Images With VGG-16 Architecture Using Transfer Learning System Tan, Nurlaila; Arif, Idam
Indonesian Journal of Physics Vol 35 No 1 (2024): vol 35 no 1 2024
Publisher : Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/itb.ijp.2024.35.1.4

COVID-19 is a respiratory disease caused by the coronavirus. The most common test technique used today for COVID-19 diagnosis is real-time reverse transcription-polymerase chain reaction (RT-PCR). However, compared to RT-PCR, radiological imaging such as X-rays and computer tomography (CT) may be a more precise, useful, and faster technology for COVID-19 classification. X-rays are more accessible because they are widely available in all hospitals in the world and are cheaper than CT scans, but the classification of COVID-19 using CT scan images is more sensitive than X-rays. Therefore, CT scan images can be used for the early detection of COVID-19 patients. One of them is using the deep learning method. In this study, a CNN algorithm with a VGG-16 architecture will be selected to classify COVID-19, intermediate, and non-COVID CT scan images using 2481 image datasets. First, pre-processing is done by resizing the image, converting the image channel into RGB, and dividing the dataset into a training dataset and a testing dataset. Then, the convolution process is continued by utilizing the pre-trained VGG-16 model from ImageNet. The results of testing the data with 97% accuracy were obtained. It is concluded that the model used to classify COVID-19, intermediate, and non-COVID CT scan images is effective and produces good results.

Co-Authors Astalini Astalini Bergas Bimo Branarto Choirul Anam AM Diponegoro Delianis Pringgenis Eko Hidayanto Freddy Haryanto Freddy Haryanto Geoff Dougherty Handayani, Nita Nita Handayani Octolia Tobigasa Tambunan Poppy Intan Tjahaja Poppy Intan Tjahaja Pratama, Sra Harke Pringgenis, Delianis Ratnawulan . Rena Widita Siti Nurul Khotimah Siti Nurul Khotimah Siti Nurul Khotimah Siti Nurul Khotimah Siti Nurul Khotimah Sparisoma Viridi Sra Harke Pratama Tan, Nurlaila The Houw Liong

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