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All Journal Jurnal Natur Indonesia TELKOMNIKA (Telecommunication Computing Electronics and Control) JURNAL FISIKA Jurnal Matematika & Sains Journal of Engineering and Technological Sciences Ta'allum: Jurnal Pendidikan Islam Jurnal Otomasi Kontrol dan Instrumentasi Jurnal Ilmu Fisika Indonesian Physical Review Indonesian Journal of Electrical Engineering and Computer Science Physics Communication Prosiding SNAST Ta'allum: Jurnal Pendidikan Islam
Mikrajuddin Abdullah
Institut Teknologi Bandung
Religion Agriculture, Biological Sciences & Forestry Astronomy Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Computer Science & IT Control & Systems Engineering Decision Sciences, Operations Research & Management Earth & Planetary Sciences Education Electrical & Electronics Engineering Engineering Industrial & Manufacturing Engineering Materials Science & Nanotechnology Mathematics Mechanical Engineering Physics Other

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Pengaruh Temperatur Penumbuhan terhadap Struktur Kristal dan Morfologi Film Tipis TiO2:Eu yang Ditumbuhkan dengan Metode MOCVD [The Effect of Growth Temperature on the Crystall Structure and Morphology of the Thin Film TiO2:Eu Grown with MOCVD Method] Edy Supriyanto; Goib Wiranto; Hery Sutanto; Agus Subagio; Mikrajuddin Abdullah; Maman Budiman; Pepen Arifin; Sukirno Sukirno; Mohamad Barmawi
Jurnal Matematika & Sains Vol 12, No 2 (2007)
Publisher : Institut Teknologi Bandung

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Abstract

Thin film of TiO2:Eu had been grown on an n-type Si(100) substrate using Metalorganic Chemical Vapor Deposition (MOCVD) method with titanium (IV) isopropoxide [Ti{OCH(CH3)2}4] 99.99% and europium nitrate [Eu(NO3)3.6H2O] 99.99% as the metal organic precursors. The tetrahydrofuran (THF) was used as a solvent for the precursor. X-ray Diffraction (XRD) analysis showed that the TiO2:Eu thin film grown at temperature of 450 οC had crystal planes of rutile (200), rutile (002) and anatase (211), whereas film grown at 500 οC resulted in a crystal plane of rutile (002) with columnar grain and surface morphology relatively smooth. On the other hand, film grown at temperature of 550 οC has rutile (200) and rutile (002) planes. The surface morphology of thin films TiO2:Eu was affected by Eu atom concentration. The roughness of surface morphology increased with increasing Eu content and therefore the grains became larger. It can be concluded that the crystal structure and surface morphology properties of the films depended significantly on the substrate temperature.
Size Dependent Phase Transition in BaTiO3 and PbTiO3: a General Theory Based on a Simple Ising Model Mikrajuddin Abdullah
Jurnal Matematika & Sains Vol 9, No 1 (2004)
Publisher : Institut Teknologi Bandung

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Abstract

A general theory based on simple Ising model has been developed to explain the effect of size on the phase transition in BaTiO3 and PbTiO3. The model can explain very well the presence of critical temperature for the occurrence of tetragonal ⇔ cubic structure, the presence of critical size where this transition to occur. Size dependent of the transition is induced by the dependence of dipole-dipole interaction in the sample on the size.
Gelation Model for Porosity Dependent Fluid Permeability in Porous Materials Mikrajuddin Abdullah; Khairurrijal Khairurrijal
Jurnal Matematika & Sains Vol 14, No 1 (2009)
Publisher : Institut Teknologi Bandung

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Abstract

A statistical theory of gel formation in a polymer matrix was used to explain the dependence of liquid permeability in porous materials. A porous material was modeled as a dispersion of bubbles in a solid matrix. Bubbles were treated as monomers and formation of infinite connected bubbles was treated as the formation of gels in polymer. The theoretical predictions were in agreement with the observed data for basalt andesits. The model can easily predict the percolation threshold of porosity at which the permeability increases suddenly, which depends on the effective number of nearest bubbles around a selected bubble. Around the percolation threshold, the permeability satisfies a scaling relationship with a critical exponent of t » 1.2. It is also identified that the critical exponent and fractal dimension of pores, D, satisfy t » 0.8 (1 + 1/D).
Dinamika Paket Gelombang Elektron yang Menerobos Penghalang Trapesium dengan Ketebalan Nanometer Maharati Hamida; Khairurrijal Khairurrijal; Mikrajuddin Abdullah
Jurnal Matematika & Sains Vol 11, No 2 (2006)
Publisher : Institut Teknologi Bandung

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Abstract

A simulation of the dynamics of electrone wave packet tunneling through a potential barrier in a MOS (metal-oxide-semiconductor) diode was performed by solving the time-dependent Schrödinger equation using the finite difference method. The wave packet is initially located in the semiconductor layer then moves toward to the oxide layer and probably tunnels through and/or is reflected by the oxide layer. The wave packet is deformed when it reaches the oxide layer. It is found that the higher the wave packet energy, the faster the wave packet moves and the higher the probability of transmitting the wave packet for the same bias voltage. It was also found that at low energy, the increase of bias voltage does not increase significantly the probability of finding the transmitted wave packet. At high energy, however, the probability of finding the transmitted wave packet becomes higher with increasing the bias voltage.
Percolation Model for Proton Immobility in Ice Abdullah, Mikrajuddin
Journal of Engineering and Technological Sciences Vol 37, No 1 (2005)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (241.717 KB) | DOI: 10.5614/itbj.eng.sci.2005.37.1.5

Abstract

A simple Ising model and a statistical theory of gel formation in a polymer matrix were combined to explain the effect of temperature on the mobility of protons in ice. Cowin et al observed that protons in ice bulk were immobile at temperatures below 190 K, and suddenly become mobile at temperatures above 190 K [Nature 398, 405 (1999)]. We proposed here that the transport of protons is controlled by a percolation mechanism. The proton transport is facilitated by the occurrence of easily reoriented water molecules in the ice bulk. The fraction of this molecule depends on temperature and was calculated using a simple Ising model. The formation of network of these molecules which provides pathways for proton transport was calculated using a statistical theory of gel formation in a polymeric system. Our model succeeded to reproduce the variation of potential difference between the ice film surfaces with respect to temperature as observed by Cowin et al based on a soft landing experiment.
Zinc Oxide Nanoparticles Prepared By a Simple Heating: Effect of Polymer Addition and Polymer Absence on the Morphology Abdullah, Mikrajuddin; Okuyama, Kikuo
Journal of Engineering and Technological Sciences Vol 36, No 2 (2004)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1682.156 KB) | DOI: 10.5614/10.5614/itbj.eng.sci.2004.36.2.5

Abstract

Zinc oxide (ZnO) nanoparticles were prepared by a simple heating of precursors in a furnace at temperatures of below 1000°C in an air environment. If zinc nitrate was used as precursor, polymer (e.g., polyethylene glycol (PEG)) must be added into the precursor to produce ZnO in nanometer size. The absence of polymer led to the presence of several micrometer-sized flakes. In addition, the heating temperatures must be higher than 500°C to completely decompose the organic material in final product. However, if zinc acetate was used as precursor, nanometer-sized ZnO having a high crystallinity can be obtained even when the polymer was absent. Interestingly, we also found that heating at low temperatures (e.g. 400°C) resulted in ZnO nanorods with an elongation ratio of around 5. This method is rapid, economically efficient, and readily scalable for industrial applications.
Fabrication of Microporous Water Filter Using Titanium Dioxide Particles, Silica Particles, and Polyethylene Glycol Priatama, Aris; Abdullah, Mikrajuddin; Khairurrijal, Khairurrijal; Mahfudz, Hernawan
Journal of Engineering and Technological Sciences Vol 42, No 1 (2010)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (561.473 KB) | DOI: 10.5614/itbj.eng.sci.2010.42.1.3

Abstract

We report the fabrication of microporous filter for use in filtering both inorganic  and  organic  substances  from  liquid  materials.  Titania  (TiO 2)  anatase was  used  as  the  main  material  for  this  filter.  Polyethylene  glycol  (PEG)  with average  molecular  weight  of  20,000  was  also  used  as  additive  to  control  the formation  of  pores,  especially  pore  sizes.  The  mixture  of  titania  and  PEG  was pressed into cylindrical tablet shape at room temperature  and then simply heated inside a furnace up to temperature where the PEG decomposed into gas to leave only connected titania particles. The use of titania as base material for the filter allows  the  organic  substances  that  trapped  inside  the  filter  pores  to  be  easily removed by heating up the used filter at above decomposition temperature of the trapped  organics.  We  also  made  other  filter  by  adding  small  amount  of  silica (SiO2)  particles  to  reduce  the  size  of  the  pores  as  well  as  to  improve  the mechanical  strength.  We  observed  that  filters  containing  silica  particles,  with smaller  in  size  compared  to  titania,  resulted  in  better  mechanical  strength, smaller in pore sizes and better filtering results in term of turbidity and dissolved oxygen (DO) content. This  method is potential for development of larger scale and cheaper water filters for use in various applications.
Metode Praktis Menentukan Arah Kiblat dan Koreksi Arah Kiblat Abdullah, Mikrajuddin
Taallum: Jurnal Pendidikan Islam Vol 5, No 2 (2017)
Publisher : Institut Agama Islam Negeri (IAIN) Tulungagung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21274/taalum.2017.5.2.209-222

Abstract

This paper explains a simple method used to determine the direction of Qibla or do the correction of Qibla direction in the mosque, mushola, or surau that already exist. The proposed method only utilizes the GoogleMap facility provided by Google. The approach is taken to draw a straight line from Ka’bah to the location where the mosque will be built. This Method is interesting to teach in Islamic high schools or Islamic education programs in colleges.
The Effect of TiO2 Coating on Pile Penetration Depth in Clay Amalia, Nadya; Asri, Asifa; Rokhmat, Mamat; Sutisna, S.; Viridi, Sparisoma; Abdullah, Mikrajuddin
Journal of Engineering and Technological Sciences Vol 49, No 5 (2017)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1874.665 KB) | DOI: 10.5614/j.eng.technol.sci.2017.49.5.6

Abstract

Pile driving tests were conducted using models of concrete piles with titanium dioxide (TiO2) coating and piles without coating. Pile surfaces coated with TiO2 become superhydrophilic, which enables water molecules in clay pores to be attracted to the pile during the pile driving process. The attraction suppresses the compression of the pore water in the clay soil, hence the result of the pile driving tests showed that piles with TiO2 coating could penetrate deeper than piles without coating with the same count of hammer strokes. An examination using FTIR confirmed the formation of bonds between water molecules for piles with coating and the absence of such bonding for piles without coating. Furthermore, it was successfully established that pile surface coating gives different results for pile driving in different clay soils.
Effect of Polystyrene Latex Addition on Size and Pore Volume of Porous Calcium Oxide Particles Prepared by Spray-Pyrolysis Method and Its Ability for SO2 Retention Septianto, Ricky Dwi; Iskandar, Ferry; Abdullah, Mikrajuddin; Khairurrijal, Khairurrijal; Hwa, Lee Myong
Journal of Engineering and Technological Sciences Vol 50, No 2 (2018)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (3896.008 KB) | DOI: 10.5614/j.eng.technol.sci.2018.50.2.6

Abstract

In this study, the effects of polystyrene (PS) latex addition on the particle morphology and the pore content of calcium oxide (CaO) were investigated. The CaO particles were prepared using an ultrasonic nebulizer-assisted spray-pyrolysis method with variation of the PS/Ca(NO3)2·4H2O mass ratio in the precursor. Good crystallinity of CaO was obtained at 825°C of synthesis temperature under 2 l/min of nitrogen gas flow, which was confirmed by Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). According to scanning electron microscope (SEM) characterization, the CaO particles synthesized with 0 and 25 wt% PS addition had an almost spherical shape with an average size of 1.58 and 1.48 µm, respectively. In addition, macropores were formed in the CaO particles prepared with 25 wt% PS addition that had an average pore diameter of 583.26 nm. Meanwhile, the CaO particles prepared with 75 wt% PS addition had a random shape and an average size of 1.41 µm. The mesopore content was investigated by Barret-Joyner-Halenda (BJH) analysis, which showed improvement of the pore size from 3.45 nm to 5.42 nm for 0 and 25 wt% PS addition, respectively, which is proportional to the pore volume, pore surface area, and the capacity of SO2 retention.
Co-Authors A. Suhendi A.A. Ketut Agung Cahyawan W Agus Subagio Amalia, Nadya Andhy Setiawan Anrokhi, Mohamad Samsul Arif Surachman Arini Fitria Gunawan Aris Priatama Asifa Asri Bebeh Wahid Nuryadin Edy Supriyanto Edy Wibowo Elfi Yuliza Endah Rahmawati Euis Sustini Fatimah A. Noor Fatimah Arofiati Noor Ferry Iskandar Fitrianingrum, Aufa Maulida Goib Wiranto Hasniah Aliah Hernawan Mahfudz Hery Sutanto Hwa, Lee Myong Ida Sriyanti Imastuti Imastuti Khairurrijal Khairurrijal Kikuo Okuyama Maharati Hamida Maman Budiman Maman Budiman Maman Budiman Mamat Rokhmat Masturi Masturi Mohamad Barmawi Muhammad Nuraliffudin Saputra Munir, Rahmawati Munir, Rahmawati Nadya Amalia Pepen Arifin Rahman, Dui Yanto Rahmawati Rahmawati Rahmawati, Rahmawati Rahmayanti, Handika Dany Riri Murniati Riska Ekawita S Saehana Septia Mahen, Ea Cahya Septianto, Ricky Dwi Sparisoma Viridi Sukirno Sukirno Sutisna, S. Ulya, Naily