Rakhmawati Farma
Kampus Bina Widya KM. 12,5 Panam Pekanbaru 28293, Riau, Indonesia

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Aplikasi Metoda Geolistrik Konfigurasi Wenner-Alpha Untuk Eksplorasi Batubara Farma, Rakhmawati
Jurnal Pilar Sains Vol 2, No 02 (2003)
Publisher : Jurnal Pilar Sains

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Abstract

Geoelectrical method uses variation of resistivity values to study subsurface geology structure, thereforeit can be applied to explore groundwater, pollution of groundwater, and geothermal exploration. In thisstudy, a physical modeling was built in the laboratory, that is used to resistivity measurement on coalsamples. The measurements employ Wenner-Alpha configuration. The result of the tests show that coallayer can be detected based on resistivity variation. The semi-antharasite sample showed higherresistivity than bituminous sample. This result is in accondance with the fact that semi antharsite drierthan bituminous sample.
PEMBUATAN DAN KARAKTERISASI KARBON AKTIF MONOLIT DARI KAYU KARET DENGAN VARIASI KONSENTRASI KOH UNTUK APLIKASI SUPERKAPASITOR Muchammadsam, Inrizky Domy; Taer, Erman; Farma, Rakhmawati
Jurnal Online Mahasiswa (JOM) Bidang Matematika dan Ilmu Pengetahuan Alam Vol 2, No 1 (2015): Wisuda Februari 2015
Publisher : Jurnal Online Mahasiswa (JOM) Bidang Matematika dan Ilmu Pengetahuan Alam

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Development of monolithic carbon electrodes with a combination of physical and chemical activation  process  can improve  performance of cell supercapacitor.  Monolithic carbon electrodes  were made  from  rubber wood cross-section of the printed form of  pellets, then  were carbonized  at temperature of  600ºC in N2  gas  atmosphere and  followed by physical activation process at 900ºC  for 2 hours in a CO2  gas atmosphere. KOH of  1 and 5 M  and  HNO3  of  25% solutions  were used as  of the chemical activation  in order  to  activate functional groups. Characterization of electrochemical supercapacitor cell utilized  two-electrode  of  cyclic voltammetry with  1 M H2SO4  solution was used as  electrolyte.  Scanning electron microscope and X-ray diffraction were carried out to study  the structure of surface morphology  and  crystalline properties of monolithic carbon electrodes.  Specific  capacitance  for electrodes  1 M KOH and 5 M KOH  was obtained  as high as  71.08 and 115.38 F/g  respectively.  These results indicate that increasing the concentration of KOH can improve the performance of the electrode supercapacitor cells.
PERFORMA SEL SUPERKAPASITOR DENGAN MENGGUNAKAN PENGUMPUL ARUS STAINLESS STEEL-NANOPARTIKEL PLATINUM Farma, Rakhmawati; Deraman, Mohamad; Awitdrus, Awitdrus
SEMIRATA 2015 Prosiding Bidang Fisika
Publisher : SEMIRATA 2015

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Abstract

Performa sel superkapasitor sangat ditentukan oleh tiga faktor utama yaitu elektrolit,  pengumpul arus dan elektroda. Elektroda karbon aktif yang disediakan dari pra- karbonisasi serabut tandan kosong kelapa sawit dengan perlakuan KOH. Karbonisasi elektroda dilakukan pada suhu 800oC menggunakan profil pemanasan multi-langkah dalam lingkungan gas N2 dan pengaktifan CO2 dilakukan pada suhu 800oC selama 3 jam. Larutan 1 M H2SO4 digunakan sebagai larutan elektrolit. Steinless Steel 316L yang telah ditumbuhkan nanopartikel platinum di atasnya digunakan sebagai pengumpul arus. Penumbuhan nanopartikel platinum di atas pengumpul arus bertujuan untuk menghasilkan sifat listrik dan elektrokimia yang lebih baik. Evaluasi terhadap nanopartikel platinum di atas pengumpul arus dilakukan dengan difraksi sinar-X yang ditandai dengan kehadiran puncak platinum (111) dan analisis energi dispersif sinar-X dengan persentase atomik platinum 3.89 %. Nilai kapasitansi sel superkapasitor berdasarkan data spektroskopi impedansi elektrokimia sebelum dan setelah penumbuhan nanopartikel platinum masing-masing sebesar 104.87 F/g dan 114.67 F/g, dan nilai hambatan seri ekuivalen menurun dari 0.438 W menjadi 0.045 W. Katakunci: Superkapasitor, Spektroskopi impedansi elektrokimia, Kapasitansi spesifik, nanopartikel platinum
PENGARUH DAYA IRADIASI GELOMBANG MIKRO TERHADAP SIFAT-SIFAT FISIKA KARBON AKTIF KAYU EUCALYPTUS Farma, Rakhmawati
Komunikasi Fisika Indonesia Vol 13, No 12 (2016)
Publisher : Komunikasi Fisika Indonesia

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The aim of this research is to determine the influence of microwave irradiation on the physical properties of activated Carbon based Eucalyptus wood. Activated Carbon were prepared from the conventional carbonized of wood Eucalyptus for 1.5 hours and microwave assisted Potassium Hydroxide with ratio of carbon and KOH of 2:1. The samples were irradiated by using the microwave for 20 minutes and the power output of 540; 630 and 720 Watt respectively.The microwave assisted Potassium Hydroxide Carbon activation are influenced of the physical properties of the samples. The higher of output power of irradiation shows the smaller of activated Carbon.The activated Carbon were irradiated with power output of 630 Watt producing the highest percentage of Methilene Blue degradation of 96.859%, where this value is supported by the highest of Lc value of 48.4733Å.] 
PEMBUATAN DAN KARAKTERISASI KARBON AKTIF DARI BAMBU BETUNG (DENDROCALAMUS ASPER) DENGAN AKTIVASI KOH BERBANTUAN GELOMBANG MIKRO Hutapea, Erin Mazelly; Iwantono, Iwantono; Farma, Rakhmawati; Saktioto, Saktioto; Awitdrus, Awitdrus
Komunikasi Fisika Indonesia Vol 14, No 2 (2017)
Publisher : Universitas Riau

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Abstract

Activated carbon had successfully been made from betung bamboo (Dendrocalamus Asper) bycarbonization process for 1 hour with chemical activation using pottasium hydroxide (KOH) with themass ratio of the carbon powder with KOH i.e. 1:0, 1:1, 1:2 and 2:1. In order to activate the carbon,the activation was help by microwave irradiation with the power of 630 Watt for 20 minutes. Thepurpose of this research is to characterize activated carbon using X-ray diffraction (XRD), FourirerTransform Infrared Spectroscopy (FTIR) and absorption of methylene blue. The data of X-raydiffraction pattern indicated that all of the activated carbon were in a semi-crystalline form, with theXRD peaks observed at angel of diffraction (2θ) of 21.268o and 41.014o with oriented of (002) and(100) respectively. The highest value of layer (Lc) is resulted from the ratio 1:1 as high as 21.495 nmand this data supported by the highestabsorption of methylene blue at ratio 1:1 as high as 99.327mg/g. Characterization of FTIR showed that the activated carbon had the function of cluster –OH, CHand C=C. Overall the calculated and analyzed results showed that the variation of KOHconcentration influences the qualities of the activated carbon.
Ionisasi Gas Butana pada Metode Pelepasan Listrik Tegangan Searah dengan Ketidakmurnian Udara Tekanan Tinggi, Plasma Termal Husein, Ikhsan Rahman; Farma, Rakhmawati; Saktioto, Saktioto
Komunikasi Fisika Indonesia Vol 14, No 1 (2017)
Publisher : Universitas Riau

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Penelitian ini dilakukan untuk menjelaskan ionisasi gas butana dengan campuran udara padatekanan tinggi. Proses kelistrikan ini menggunakan elektroda grafit pensil yang digunakan untukmelucuti gas pembentukan plasma dengan metode electrical-discharge pada rentang tekananatmosfir. Plasma Karbon diproduksi dengan mengoperasikan tegangan (DC)<3,5kV danmengalirkan gas butana ke dalam tabung plasma. Hasil eksperimen menunjukkan tegangan jatuh danarus listrik. Tegangan dan arus listrik diperoleh sebelum dan sesudah terjadi breakdown. Densitasdan temperatur plasma Karbon dihitung dari arus listrik dan tegangan jatuh. Hasil eksperimenmenunjukkan ionisasi udara pada tekanan rendah memiliki tegangan maksimum 570V, teganganjatuh 530-570V dan arus listrik 0,27-0,45mA, sedangkan pada tekanan tinggi memiliki teganganmaksimum 1160V, tegangan jatuh 900-1100V dan arus 0,46-0,6mA. Ionisasi yang terjadi saatpenambahan gas butana (ketidakmurnian campuran udara) pada tekanan rendah memiliki teganganmaksimum 772V, tegangan jatuh 536-775V dan arus listrik 0,03-0,45mA, sedangkan pada tekanantinggi memiliki tegangan maksimum 1044V, tegangan jatuh 675-1055V dan arus listrik 0,03-0,69mA.Hasil data ini berhubungan dengan variasi distribusi gas yang berada didalam tabung. Hasileksperimen diharapkan dapat digunakan untuk pengembangan pertumbuhan Carbon Nano Tubepada ujung katoda.
PENGARUH DAYA IRADIASI GELOMBANG MIKRO TERHADAP SIFAT-SIFAT FISIKA KARBON AKTIF KAYU EUCALYPTUS Farma, Rakhmawati
Komunikasi Fisika Indonesia Vol 13, No 12 (2016)
Publisher : Universitas Riau

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Abstract

The aim of this research is to determine the influence of microwave irradiation on the physical properties of activated Carbon based Eucalyptus wood. Activated Carbon were prepared from the conventional carbonized of wood Eucalyptus for 1.5 hours and microwave assisted Potassium Hydroxide with ratio of carbon and KOH of 2:1. The samples were irradiated by using the microwave for 20 minutes and the power output of 540; 630 and 720 Watt respectively.The microwave assisted Potassium Hydroxide Carbon activation are influenced of the physical properties of the samples. The higher of output power of irradiation shows the smaller of activated Carbon.The activated Carbon were irradiated with power output of 630 Watt producing the highest percentage of Methilene Blue degradation of 96.859%, where this value is supported by the highest of Lc value of 48.4733Å.
PENGARUH WAKTU PERENDAMAN DALAM PEMBUATAN KARBON AKTIF CANGKANG BUAH KETAPANG DENGAN PENGAKTIFAN KIMIA BERBANTUAN IRADIASI GELOMBANG MIKRO Rukmana, Desy Veyka; Farma, Rakhmawati
Komunikasi Fisika Indonesia Vol 13, No 13 (2016)
Publisher : Universitas Riau

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Activated carbon were prepared from shell of Terminalia cattapa. The shell of Terminalia cattapa werecarbonized by conventional carbonization for 3 hours. The ratio of mass percentase of carbon granular: KOH is 2 : 1. The mixtures of carbon granular and KOH were soaked in 200 mL boilong water for 12hours, 24 hours and 36 hours. Subseguent by irradiated with output power of 630 watt for 20 minutes.The samples were characterized by using scanning electron microscopy and EDX, and BET. Carboncontent and BET surface area of sampel are 66,23 % - 69,26 % and 285,85 m2/g - 293,36 m2/g,
KARAKTERISASI SIFAT FISIS DAN ELEKTROKIMIA SEL SUPERKAPASITOR DENGAN PENUMBUHAN NANOPARTIKEL PLATINUM DI ATAS PENGUMPUL ARUS Farma, Rakhmawati; Hasibuan, Rinti Rahimah
Komunikasi Fisika Indonesia Vol 14, No 2 (2017)
Publisher : Universitas Riau

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Abstract

Supercapacitor is composed of several components namely, electrolyte separator, currentcollector, and carbon electrode. Manufacture of electrodes that make from raw fibres of oil palmempty fruit bunches (STKKS) through a combination of chemical activation using KOH activatorwith concentration variation of 0.3 M, 0.9 M and 0.6 M. The carbonization process was carried out ata temperature of 600°C using the N2 gas and was continued with the physical activation process at atemperature of 700°C with the use of CO2 gas. The growth of platinum nanoparticles above the currentcollector can enhance the performance of supercapacitor cells. Characterization of the physicalproperties of supercapacitor cell electrodes using Field Emission Scanning Electron Microscopy(FESEM) showed that electrode with KOH concentration of 0.3 M has more porous and distributedevenly for 0.6 M, 0.9 M. Moreover, the results of FESEM for current collectors show platinumnanoparticle were found to grow evenly. X-ray diffraction studies for carbon electrodes indicated thatthese electrodes has can semicrystalline state with angle of diffraction of 24° and 44° for planesorientation of 002 and 100 respectively. Characterization of electrochemical properties using CyclicVoltametry (CV) showed that platinum nanoparticles growth above current collectors have the largestspecific capacitance value of 149.627 F/g with a concentration of 0.3 M.
PENGARUH KONSENTRASI KALIUM HIDROKSIDA DAN IRADIASI GELOMBANG MIKRO TERHADAP KUALITAS KARBON AKTIF DARI SERABUT TANDAN KELAPA SAWIT Farma, Rakhmawati; Tania, Nurul
Komunikasi Fisika Indonesia Vol 14, No 1 (2017)
Publisher : Universitas Riau

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Abstract

Activated carbon as research creating absorbent material through process pre-carbonization andchemical activation used potassium hydroxide with help of microwave irradiation. The activationprocess using KOH concentration variation of 1 M, 2 M, and 3 M. The objective of this research wasto investigate effect of KOH activator concentration on the characteristic of the activated carbonthrough the analysis of yield activated carbon, activated carbon adsorption of the methylene blue,cristalinity properties and surface morphology activated carbon. The best results were obtained inKOH concentration 2 M on methylene blue 90,60 mg/g, SEM analysis showed that incressing thepower of KOH concentration will produce more quantity of pore and more regular pore structurewhich content of carbon is 68,47%.