Articles

Pengaruh Temperatur Terhadap Pembentukan Pori-Pori Arang Karbon Aktif Ampas Tebu Malik, Usman
Komunikasi Fisika Indonesia Vol 9, No 04 (2012)
Publisher : Komunikasi Fisika Indonesia

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Pengaruh temperatur terhadap pembentukan pori-pori arang karbon aktif ampas tebumenggunakan analisa XPD dan SEM. Susunan dari atom karbon ampas tebu adalah berupaamorf, dan tidak menunjukkan ciri-ciri struktur kristal yang tidak memiliki puncak energi.Dengan memberikan variasi suhu pada sampel memberikan pengaruh terhadap letak, lebar,dan tinggi dari puncak puncak difraktogramnya. Terdapat perubahan pada puncak dimanasemakin tinggi suhu yang diberikan akan menyebabkan posisi puncak pada grafik akansemakin dimana posisi terhadap sudut theta akan semakin tinggi. Ini juga menyebabkanperubahan pada puncak difraktogram.
Pengaruh Temperatur Terhadap Puncak Difraktogram Pada Arang Tempurung Kelapa Sawit Malik, Usman
Komunikasi Fisika Indonesia Vol 9, No 5 (2012)
Publisher : Komunikasi Fisika Indonesia

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Telah dilakukan penelitian dengan menggunakan analisa difraksi sinar-x dan analisa Energi Dispersive Atomic X-Ray (EDAX) pada sampel penelitian karbon tempurung kelapa sawit. Spektrum difraksi sinar-x sampel karbon tempurung kelapa sawit memiliki struktur yang amorf dengan dua peak energi pada intensitas 639 A.U dan 232 A.U (Arbitari Unit). Unsur-unsur yang terdapat pada karbon tempurung kelapa sawit selain mengandung unsur karbon C sebesar 98,48% juga terdapat unsur lain yaitu silikon Si sebesar 0,71 %. Pada analisa EDAX didapat persentase atomik unsur penyusun adalah karbon C sekitar 99,69% dan silikon Si 0,31 %. Dengan analisa SEM didapat bentuk penampang melintang yang tidak beraturan, sehingga dapat disimpulkan bahwa karbon tempurung kelapa sawit bersifat amorf.
Avo Fluid Inversion (AFI) Untuk Analisa Kandungan Hidrokarbon Dalam Resevoar Edisar, Muhammad; Malik, Usman
Komunikasi Fisika Indonesia Vol 9, No 5 (2012)
Publisher : Komunikasi Fisika Indonesia

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Selama ini metoda AVO telah banyak digunakan untuk men-determinasi keberadaan hidrokarbon daridata seismik. Namun demikian, pada umumnya hanya memberikan hasil secara kualitatif, tanpa kuantifikasitingkat kepercayaan. Oleh karena itu, diperlukan suatu metoda yang dapat membantu mengatasi masalah ini.AVO Fluid Inversion (AFI) merupakan perluasan dari metoda AVO konvensional. Perluasandilakukan dengan menambahkan simulasi harga Intercept (A) dan Gradient (B) untuk berbagai kemungkinanharga parameter elastik sand dan shale serta kandungan fluidanya. Harga A dan B yang diturunkan dari dataseismik kemudian dapat dikalibrasikan terhadap data sumur dengan menggunakan hasil simulasi tersebut.Sehingga pada akhirnya, dapat diberikan harga probabilitas keberadaan hidrokarbon pada area studi yangkemudian dapat digunakan untuk menggambarkan penyebaran hidrokarbon pada daerah eksplorasi.Pada penelitian ini, metoda AVO Fluid Inversion (AFI) diaplikasikan pada data 3D-seismik di daerahdelta Mahakam. Hasil menunjukkan bahwa determinasi keberadaan gas lebih mudah dilakukan dibandingkandeterminasi keberadaan minyak (oil). Peta probabilitas hidrokarbon menggambarkan keberadaan minyak dangas mengikuti pola-pola channel yang berkembang pada daerah studi.
PEMBUATAN RANGKAIAN INVERTER DARI DC KE AC Dewi, Rahmi; Malik, Usman
Komunikasi Fisika Indonesia Vol 8, No 3 (2011)
Publisher : Komunikasi Fisika Indonesia

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Telah dilakukan penelitian secara eksperimen tentang pembuatan alat yang dapat mengubah tegangansearah menjadi tegangan bolak-balik. Alat tersebut dinamakan dengan inverter. Sumber tegangansearah yang digunakan yaitu sebuah baterai dengan tegangan 12 volt dan arus 60 ampere. Prinsipkerja dari rangkaian inverter ini yaitu tegangan searah dari baterai diubah dengan menggunakantransistor yang berfungsi sebagai sakelar otomatis dan diatur bekerja secara bergantian. Sehingga padabeban akan timbul arus bolak balik pada suatu perioda yang merupakan gelombang sinus setengahgelombang pertama pada posisi positif dan setengah gelombang kedua pada posisi negatif.Selanjutnya akan menghasilkan tegangan bolak-balik yang besarnya 12 volt. Untuk menaikkantegangan bolak-balik tersebut digunakan transformator. Rangkaian inverter pada penelitian ini dapatmenghasilkan tegangan keluaran yaitu sebesar 110 volt, 150 volt dan 220 volt. Untuk tegangankeluaran 110 volt, inverter dapat menahan beban sebesar 70 watt. Untuk tegangan keluaran 150 volt,inverter mampu menahan beban sebesar 100 watt dan untuk tegangan keluaran 220 volt, invertermampu menahan beban 220 watt.Keywords: Rangkaian Inverter, Tegangan Bolak-balik
PENELITIAN BERBAGAI JENIS KAYU LIMBAH PENGOLAHAN UNTUK PEMILIHAN BAHAN BAKU BRIKET ARANG Malik, Usman
2302-0792
Publisher : Edu Research

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The waste of timber industry can be utilized to producesome valuable products. A research had been conducted tostudy such possibility. The research was to study the conversionof wood into charcoal briquetting using adhesive or heatingprocess. Result showed that the heating value of charcoalbriquetting made from kempas wood (koompassia malaccensismaing), meranti (shorea spp.) and pulai (alstonia spp)increases significantly compared to that of raw material. Theproduct made from kempas wood (koompassia malaccensismaing.) was formed to have the highest energy per cc (density)followed by those of made of meranti (shorea spp.), ramin(gonystylus bancanus kurz.). However, raw materialavailability must be consideret in establishing charcoalbriquetting industry.
EFEK SUHU TERHADAP PEMBENTUKAN BESARAN BUTIRAN ARANG KARBON TEMPURUNG KELAPA SAWIT Malik, Usman
2302-0792
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Research has been carried out using x-ray diffraction analysis and analysisof Atomic Energy Dispersive X-Ray (EDAX) on a sample of oil palm shellcarbon. X-ray diffraction spectrum of a sample of oil palm shell carbon has anamorphous structure with two peaks in the energy intensity of 639 AU and 232AU (Arbitari Unit). The elements contained in the oil palm shell carboncontaining elements other than carbon C amounted to 98.48% of other elementsthat are also contained 0.71% Si silicon. EDAX analysis of the percentageobtained on the building blocks of atomic carbon C is approximately 99.69% and0.31% Si silicon. SEM analysis obtained by cross-sectional shape is irregular, soit can be concluded that oil palm shell carbon is amorphous, and visible changesin the peak position, width and height of the temperature difference diffractogramto the formation of massive carbon charcoal granules.
EFEK ADITIF Bi2O3 TERHADAP MIKROSTRUKTUR DAN KOEFISIEN NON LINEAR VARISTOR ZnO. Tambunan, Walfred; Malik, Usman
2302-0792
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The varistor ZnO has been made by using raw materials: ZnO(E-Merck) and additive 0 %, 2.5 %, 5%, 7.5%, and 10% wt.Bi2O3. The important property of varistor ZnO is coefficient ofnon linier () and it can give influence correlation betweencurrent I and voltage V. The mixing process of raw materialswas done by using magnetic stirrer and liquid acetone asmedia, and then was dried at 60oC, and also grinded untilpassing 400 meshes. Pellet was made by using pressing 50MPa, and fired at 1050oC with holding time 2 hours. Afterfiring, all samples are characterized, such as: measurement ofcoefficient of non linier (), and observation of microstructureby using Scanning Electron Microscope (SEM). The resultsshow that sample without additive has  less than 5 and thissample has not properties as varistor, but the highest value of is 64 for sample with additive 7.5% Bi2O3. The result ofphotos SEM shows that the increase of percentage of additiveBi2O3 can influence of formation grain boundary and grainsize. Where, value of coefficient of non linier () is depend onexisting of grain boundary and thickness of grain boundary.
RESERVOIR STEAM FLOOD MODELING BASED ON 4D SEISMIC AND ROCK PHYSICS Edisar, Muhammad; Malik, Usman
Komunikasi Fisika Indonesia Vol 10, No 7 (2013)
Publisher : Komunikasi Fisika Indonesia

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Reservoir steam flood modeling based on Time Lapse (4D) seismic and Rock Physics data was constructed in Pelangi oil field on central Sumatra Basin. Model used to monitoring and tracking steam flood and production related changes in the reservoir. A model of the reservoir steam flood was constructed for a pattern steam flood in Area X of the field. The model was based on a geostatistical geological model and populated with temperature and porosity. Pressure and saturation properties were added to provide the necessary input for seismic modeling. Through a rock physics model based on the core analysis, the elastic properties (Vp, Vs and density) were determined. These elastic properties were used to determine the seismic response of the model with and without steam flood.The results of the model indicated, that from the rock physics modeling using Gassmann equation, steam flood decreases the Vp by an average of 20-25% in the reservoir sands. Rock physics analysis also shown that shear velocities are also sensitive to steam flood, with an average decrease of 12%. However, the Gassmann calculation results shown that Vs is insensitive to steam flood. This discrepancy is probably caused by Gassmanns assumptions that no chemico-physical interactions exist between the rocks and pore fluids. Time shifts in seismic modeling events provided an indication of the presence of steam flood in the overlying reservoir. The relationship between time shift and steam thickness was strong for thick steam, but it was not possible to distinguish thin steam zones from thick hot oil zones solely on the basis of time shift. At the same time, tuning between the steams related and geologically related seismic events influenced seismic amplitudes. It appears that a combination of attributes is necessary to resolve the effects of steam on the 4D seismic data acquired over of the field.Keywoods : Reservoir, Seismic, Rock
Investigation on the MHz-THz Radiation Field Regime Absorption in Cancer-Health Cell Tissue Hamdi, Muhamad; Malik, Usman
Komunikasi Fisika Indonesia Vol 10, No 7 (2013)
Publisher : Komunikasi Fisika Indonesia

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This paper focuses on the thermoregulation rise due to exposure of the MHz-THz radiation field regime in cancer-health cell tissue. In fact it may occur some processes such as absorption, transmission, reflection and scattering when this radiation interacts with tissue. It depends on the exposure power source. During in cell tissue there is basically the existence of this radiation field contribution to the cell tissue bioelectric and bio magnetic field result in heat production rate. It has a source from excitations of cell macromolecule photonic-phonon vibrations. The self cell tissue has the periodic bio potential with a small cellular volume results in the bioelectric field. This main reason we investigate and solve the simultaneous equations using Maxwell, heat conduction and sinusoidally modulated intensity equation with spectral method. We assume a small tissue piece to form the spherical or cylindrical cell membrane layer. Absorption involves the extraction of vibration energy from MHz-THz radiation regime field by a cell macromolecular species; the vibration must cause a change in the cell electric dipole moment. Energy absorption is the primary mechanism that allows radiation field of MHz-THz source to produce physical effects on tissue for treatment purposes. While transitions between two energy levels of a molecule that are well defined at specific THz wavelengths could serve as a spectral fingerprint of the cancer molecule for diagnostic purposesKeywords :MHz-THz radiation, absorption, cell tissue , macromolecule, excitation, photonic-phonon vibration
KARAKTERISASI DIFFRAKSI SINAR-X (XRD) MATERIAL FERROELEKTRIK BARIUM TITANAT (BaTiO3) Dewi, Rahmi; Malik, Usman
Komunikasi Fisika Indonesia Vol 10, No 7 (2013)
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Ferroelectric material Barium Titanat (BaTiO3) has been made with the comparison of 1:1from chemical reactionof Barium Carbonat (BaCO3) and Oxide Titanium (TiO2). The sample at pra-sinter at temperature of 400oC and printed in the form of pellets.The pellet were anneled with the temperature of 700oCand then characterized using XRD. The results of characterization using XRD was described on a graph between the intensity versus 2 theta angle. TheXRDresultsBaTiO3 before annelingdoes not show any peaks, this mean that the structure of BaTiO3before annelingis amorfus structure. The XRDresult BaTiO3 after annelingshowedsome peaks, the positions of the peaks on 2θ are 23.32°, 32.72°, 38.40o, 45.52o, 52.04°, 57.80o. After anneling, the peaks become wider, this mean the samples become crystaline in structure. At standard temperature (0oC to 320oC) the samples of BaTiO3 has tetragonal formbut on the temperature 700oC after being anneledit changed into Cubic.Keywords:CharacterizationXRD; BaTiO3; AnellingTemperature