Spektra: Jurnal Fisika dan Aplikasinya
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FLOW UNITS DETERMINATION USING FLOW ZONE INDICATOR FOR CARBONATE RESERVOIR
Get PDFIn the last few years, the use of flow unit technique in the oil and gas industry has shown a great deal of success. Porosity and permeability from wire-line log and special core data analysis (SCAL) along with its cementation exponent value were integrated to characterize the reservoir in terms of pore volume caused by facies changing. In this work, we determine flow unit of the carbonate reservoir, which is applied to the Northwest Java Basin Field, Indonesia by performing the flow unit analysis, which allows approximating absolute permeability. Furthermore, the quantity and the flow unit of the reservoir rock is also determined to identify the secondary porosity. To reduce the level of uncertainty, wire-line logs data were validated with core data before it is used to interpret the reservoir. Subsequently, the result can be extrapolated to un-cored wells. Our experiment shows that flow units can be determined reliably from the integration between porosity and permeability, which have defined two different rock types in term of flow unit zone. The correlation of the flow units between wells leads to the definition of reservoir quality
FABRICATION AND CHARACTERIZATION OF THE COMPOSITES OF RESIN - HUSK OF RICE AND RESIN - RUB ASH
Get PDFWe have done the fabrication of two kinds of composite material the fillers that we used rub ash for one type of composite and the husk of rice for another, the matrix for both is resin. The resin - rub ash composite, the volume ratio of filler and matrix is 1:1, while in the resin - husk of rice composite we used three volume ratios, those are 1:1, 1:2, and 2:1. After the process of fabrication was done, we did TGA test and three points flexural test for every composite we fabricated. The results of TGA test show that the most significant weight decrease of resin - rub ash composite occurred at 390,29 ºC, while the resin - rub ash composite's most considerable weight decrease occurred at 399,86 ºC. The results of three points flexural test show that elasticity of resin - rub ash composite is 4,97 x 109 N/m2, while elasticity modulus of all kinds of the resin - husk of rice composite is in order of 108 N.m2 and 106 N/m2. Overall, we can conclude that the resin - husk of rice composite is more heatproof and more elastic than the resin - rub ash composite
THE EFFECT OF SYNTHETIC ZEOLITES ON SENSITIVITY AND STABILITY OF URIC ACID BIOSENSOR USING CYCLE VOLTAMETRY METHOD
Get PDFThe synthesis of synthetic zeolite modified biosensor material has been carried out to detect uric acid. This study aims to look at the effect of synthetic zeolite on uric acid biosensor material on sensor stability and sensitivity. The biosensor was use to measure uric acid using uricase produced Lactobacillus plantarum. Modification of biosensor material using synthetic zeolite content of Sodalit is added in a mixture of graphite and paraffin. Carbon paste electrode (EPK) was made with graphite and paraffin comparison 70 mg : 30 mg, while zeolite modified carbon paste electrode (EPKZ) with graphite, paraffin and zeolite comparison 50 mg: 30 mg: 20 mg. In each electrode, 7.5 μl of L.plantarum pellet (EPKZLP) was dropped. Electrode performance testing was carried out using Cyclic Voltammetry. Modification results affect biosensor performance such as sensitivity and stability. The highest current is produced by EPKZLP with a current range of 0.0143 - 0.0592 mA. The best sensitivity is produced in EPKZLP with a value of 0.031 mAcm-2mM-1. The best stability was found in EPKZLP with a percentage of stability on day 14 was 30.9%. The average standard deviation generated in this study is 0.0024 mA with a relative error value was 7.8%. Addition of zeolite to biosensor material produced in this study has met several criteria to be used as a sensor.
Keywords: uric acid biosensor, zeolite, sodalit, sensitivity, stability.
 
SYNTHESIS OF SODALITE ZEOLITE FROM COAL BOTTOM ASH WITH VARIATION OF NaAlO2 CONCENTRATION USING ALKALI MELTING HYDROTHERMAL METHOD
Get PDFSynthesis of zeolites from bottom ash using alkali melting hydrothermal method with variation concentration of NaAlO2 solution had been done. Concentration of NaAlO2 solution was varied for 2,5 M (Z1), 2 M (Z2), 1,5 M (Z3) and 1 M (Z4). The bottom ash and NaOH are melted for 3 hours at 750C. Then, the sample is heated through a hydrothermal process with NaAlO2 crystallization medium. Then the sample is neutralized with aquades up to pH 9-10. Characterization of sample includes characterization zeolite type using of. The results of characterization using XRD show that the zeolite formed on samples Z1, Z2, and Z3 are zeolites of sodalite type and on Z4 sample of zeolite type are sodalit, nosean, and megakalsilit. The highest sodalite purity was obtained in Z3 sample, which is 73%
IDENTIFIKASI KETEBALAN LAPISAN SEDIMEN DAN STRUKTUR BAWAH PERMUKAAN DI ZONA AMBLESAN KOTA LAMA SEMARANG BERDASARKAN DATA MIKROSEISMIK
Get PDFSebagai kota di pesisisr panatai pulau Jawa Semarang merupakan tempat yang bersejarah dengan bangunan-bangunan kuno peninggalan Belanda yang disebut kota lama. Dalam rangka melestarikan kota lama peninggalan bersejarah tersebut perlu dilakukan kajian struktur bawah permukaan karena Semarang ini terutama daerah yang tersebar endapan alluvial sehingga memungkinkan terjadi Amblesan (subsidence). Amblesan ini dapat mengakibatkan banjir di daerah Semarang utara akibat banjir pasang (rob), serta terjadi kerusakan pada bangunan-bangunan peninggalan bersejarah tersebut. Amblesan ini disebabkan oleh beban berat di atas lapisan, deformasi lapisan tanah permukaan dan pemompaan air tanah kepermukaan. Potensi amblesan ini dapat diketahuai melalui kajian struktur bawah permukaan dengan metode mikroseismik. Mikroseismik merupakan metode geofisika yang sering digunakan untuk survey pendahuluan mendeteksi ketidakstabilan lapisan batuan dengan memanfaatkan getaran kecil dari gelombang seismic. Akuisisi data dilakukan dengan menggunakan salat Seismometer 3 komponen dan kemudian diolah dengan metode HVSR. Dari hasil pengolahan data diperoleh ketebalan lapisan sedimen pada kawasan gereja Blenduk berkisar antara 68-116 meter. Kondisi struktur bawah permukaan di kawasan Gereja Blenduk yaitu terdiri dari batuan aluvial yang terbentuk dari sedimentasi delta, top soil, lumpur, dll dengan kedalaman 30m atau lebih. Ketebalan sedimen permukannnya sangatlah tebal
STUDI SIFAT ELEKTROKIMIA SEL BATERAI SEKUNDER POUCHCELL LITHIUM ION LIFEPO4/GRAPHITE APLIKASI DAYA TINGGI
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Telah dilakukan pembuatan lembaran katoda dari serbuk LiFePO4 komersial dan anoda dari serbuk Graphite. Lembaran difabrikasi membentuk sel penuh baterai dengan tipe sampel uji berbentuk Pouchcell. Konfigurasi sel adalah LiFePO4//LiPF6//graphite, LiPF6 digunakan sebagai elektrolit cair. Karakterisasi sel dilakukan meliputi uji cyclic voltrametry, charge discharge dan EIS (electrochemical Impedance Spectroscopy. Nilai yg dihasilkan adalah kapasitas mencapai sekitar 80 mAh/gr, dengan tegangan Voc stabil pada nilai 3.28 V. Nilai discharge capacity yang bisa diambil hingga 5C lebih dari 40%, dengan life cycle pada 50 siklus kehilangan kapasitas hanya kurang dari 5%.
Kata-kata kunci: pouchcell, cyclic voltametry, electrochemical impedance spectroscopy, baterai high power.
Abstract
In this work, have been fabricated cathode electrode from LiFePO4 powder and anode from commercial Graphite powder. Full cell batteries fabricated in Pouchcell shaped test samples. Lithium ion cell configuration are LiFePO4 // LiPF6 // graphite, 1 M LiPF6 in EC/DEC is used as the liquid electrolyte. Cell batteries Perfomance characterized by some tests conducted on the cyclic voltrametry, charge-discharge and EIS (electrochemical impedance spectroscopy. The result value are the capacity reached approximately 80 mAh / g, with the voltage Voc perfectly stable at 3.28 V. The discharged capacity can be taken up to 5C almost over 40% , with after 50 cycles for life cycle test the capacity loss is retain still 95% at 0.33C.
Keywords: pouchcell, cyclic voltametry, electrochemical impedance spectroscopy, high power battery
KONDISI GEOLOGI LOKAL KOTA BENGKULU BERDASARKAN GROUND SHEAR STRAIN (GSS)
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Kondisi geologi lokal merupakan salah satu parameter yang mempengaruhi tingkat kerusakan akibat gempabumi. Kondisi geologi kota Bengkulu telah digambarkan oleh nilai Ground Shear Strain (GSS) yang diperoleh dari hasil analisis enam puluh tujuh data mikrotremor yang dipasang di setiap jenis formasi geologi. Berdasarkan hasil analisis, nilai GSS kota Bengkulu relatif heterogen meskipun pada jenis formasi geologi yang sama. GSS kota Bengkulu diperoleh dan dibagi dalam tiga kelompok, diantarany 10-6 (25.37%), 10-5 (40.30%) dan 10-4 (32.84%). Variasi ini mengindikasikan adanya perbedaan ketebalan lapisan sedimen dan tingkat kekerasan batuan untuk setiap titik amat. Wilayah yang memiliki nilai GSS tinggi memiliki kesesuaian dengan kondisi lapangan yang sebenarya (berdasarkan hasil ground survey merupakan daerah bekas rawa dengan mofologi landai) dan kesesuaian dengan sejarah kerusakan akibat gempabumi besar di kota Bengkulu. Berdasarkan peta sebaran nilai GSS, potensi deformasi paling tinggi terindentfikasi di bagian barat Kota Bengkulu yaitu wilayah dengan formasi geologi undak alluvium, alluvium dan sebagian formasi andesit, sedangkan formasi geologi lainya relatif lebih aman. Dinamika lapisan tanah permukaan kota Bengkulu umumnya bersifat elastis dan berpotensi mengalami rekahan dansettlement. Struktur geologi yang relatif lunak dan lapisan sedimen yang tipis memungkinkan terjadinya penguatan efek gelombang dan resonansi tinggi ketika gempabumi terjadi.
Kata-kata kunci: Kondisi geologi lokal kota Bengkulu, Ground Shear Strain, deformasi.
Abstract
Local geology condition has become one of the most parameters which affected damage level of earthquake. Geology condition of Bengkulu city has been described by Ground Shear Strain (GSS) value that obtained by sixty seven microtremor data analysis result what instaled on each geology formation types. According analysis result, GSS value of Bengkulu city was heterogeneous relatively in spite of similar geology formation type. GSS in Bengkulu City has obtained and be divided to three category, including 10-6 (25.37%), 10-5 (40.30%) and 10-4 (32.84%). These variations indicate differences in the thickness of sediment layer and rock solidity level of sites. The Areas of high value of GSS have compatibility with actual field conditions (Based on ground survey, it was swamp area and morphology ramps relatively) and have compatibility with damaged earthquake effect history of Bengkulu city. According map of GSS value distributions, high potency of deformation was indicated in western of Bengkulu city area, it was alluvium terraces formation, alluvium formation and partial of andesite formation, while others were relatively safer. The dynamic characteristic of surface soil layer on Bengkulu city was elastic and potential crack and settlement.The soft geology structure relatively and thin of sediments layer would affected amplification of wave and high resonance when earthquake occur.
Keywords: Local geology condition of Bengkulu city, ground shear strain, deformation of soi
PENENTUAN PERCEPATAN GRAVITASI PADA PERCOBAAN GERAK JATUH BEBAS DENGAN MEMANFAATKAN RANGKAIAN RELAI
Get PDFThe determination of the gravity acceleration through free fall experiment using the relay circuit has been done. This study aims to make free-fall experiment design using relay circuit, and determine the value of gravity acceleration by using this experiment design. The measurement method used in this study is to measure the free fall time of the object using a stopwatch that can work automatically. The result of this research is this experiment design can be used to get the free fall time data automatically. The values of gravity acceleration to 10 cm, 20 cm, 30 cm, 40 cm and 50 cm respectively, are 9.80952381 m/s2, 9.814058957 m/s2, 9.845 m/s2, 9.858283385 m/s2, and 9.829645226 m/s2. So that the average acceleration value of the five variations of height is 9.831302275 m/s2.
Keywords: Free fall motion, gravity acceleration, relay circuit
