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Ivandini Tribidasari A.
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Makara Journal of Science
Published by Universitas Indonesia
ISSN : 23391995     EISSN : 23560851     DOI : https://doi.org/10.7454/mss
Core Subject :
Makara Journal of Science publishes original research or theoretical papers, notes, and minireviews on new knowledge and research or research applications on current issues in basic sciences, namely: Material Sciences (including: physics, biology, and chemistry); Biochemistry, Genetics, and Molecular Biology (including: microbiology, physiology, ecology, taxonomy and evolution); and Biotechnology.
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Articles 23 Documents
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Search results for , issue "Vol. 11, No. 2" : 23 Documents clear
PENGARUH PELAPISAN PERMUKAAN PARTIKEL SiC DENGAN OKSIDA METAL TERHADAP MODULUS ELASTISITAS KOMPOSIT Al/SiC Zainuri, M; Siradj, Eddy S; Priadi, Dedi; Zulfia, Anne; Darminto, Darminto
Makara Journal of Science Vol. 11, No. 2
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The Influence of Coating Oxide Metal on Surface of SiC Particles to Elastic Modulus of Al/SiC Composites. The isotropic composites of Al/SiC is made by powder metallurgy method, the quality of mechanical materials depend on interfacial bonding between matrix (Al) and reinforcement (SiC). The quality of interfacial bonding can influence to elastic modulus of composites which is made by solid process. SiC particles were coated by metal oxide aim to enhance quality interfacial bonding between matrix and reinforcement. These research using three kinds of coating materials, which are Mg oxide, Cu oxide and Al oxide, and these materials were deposited on surface of SiC particles. From three kinds of materials coating Al2O3 is the best to enhance quality interfacial bonding between matrix and reinforce than the others as CuO or MgO. There is Intermetalic phase formatted on CuO coating, and MgO coating have many porous where they can make decrease quality of Al-SiC composites. All of volume fraction of SiC on the Al/SiC composites, which oxide aluminum coating on SiC surface have highest value of elastic modulus than the others metal oxides.
STRUKTUR KECEPATAN GELOMBANG S DI BAWAH INDONESIA MELALUI ANALISIS SEISMOGRAM GEMPA-GEMPA BUMI DI SEKITAR INDONESIA PADA STASIUN OBSERVASI UGM Santosa, Bagus Jaya
Makara Journal of Science Vol. 11, No. 2
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Seismogram Analysis of Earthquakes Around Indonesia In UGM Observational Station: S Velocity Structure. The seismogram comparison between the measured and synthetics seismogram has been carried out in observation station of UGM, where the seismograms are excited by earthquakes that occurred at North Sumatra, Sumbawa, Sunda Strait, around North Celebes and PNG. The ray paths from earthquake's hypocenter to UGM give opportunity to understand the earth structure alongside the front area of subduction zone. The calculation of synthetic seismogram needs input in the form of earth model, the Centroid Moment Tensor (CMT) solution of the earthquake and location of observation station, as well as the relevant date file response of the observation station. Waveform comparison and fitting at surface wave indicate that speed's anomalies in the lithosphere have negative character in front area of subducted zone, but become positive for northern area of subduction zone. By paying attention to waveform of Love surface wave, it is obtained, that this waveform are sensitive to the change of earth crust thickness, while Rayleigh waveform is not sensitive. Heterogeneity is not only occurred in the lithosphere, but also in deeper earth layers, until Core Mantle Boundary (CMB). Different corrections are needed to make the fitting at S secondary wave, but also at depth wave and its repetitions. The result of this research shows that the research area, which is located in the front of subduction zone has anomalies at S speed of at deeper earth layers which than the lithosphere. The earth structure as the result of this research differs from the other seismological results, where they used the methods, which are based on inversion of arrival time data of body wave and dispersion analysis on surface wave.
PENGARUH JANGKAU SUDUT UKUR PADA HASIL ANALISIS DATA DIFRAKSI SINAR-X MENGGUNAKAN METODE RIETVELD: KASUS CAMPURAN MgO-Y2O3 Suminar, Suminar
Makara Journal of Science Vol. 11, No. 2
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Selection of Diffraction Measurement Range and Its Effect on X-ray Diffraction Rietveld Analysis Results: a MgO-Y2O3 Mixture Case. X-ray diffraction data analyses for a MgO-Y2O3 (30% Y2O3 by weight) ceramic composite have been done at various diffraction angle ranges to evaluate the effects to the analyses results. The study was performed as choosing the angle ranges correlates to data collection time and x-ray tube lasting. The analyses utilised Rietveld-based software Rietica. The ranges chosen were (A) 10-100, (B) 10-90, (C) 10-80, (D) 10-70 dan (E) 10-60 °2θ. Results showed that in general the errors of the refined parameters increased with narrower range. Phase composition analyses also showed significant bias when narrower range was used – with range 10-80 °2θ gave tolerable result. Moreover, narrowing diffraction angle in the analysis significantly biases the Lorentzian peak broadening component values particularly for phase with crystallite size estimate more than 100 nm. The study recommends how to choose the range.
MODEL-INDEPENDENT EXTRACTION OF THE KΛp COUPLING CONSTANT Mart, Terry
Makara Journal of Science Vol. 11, No. 2
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We have extracted the kaon-hyperon-nucleon coupling constant by means of a model-independent method and recent experimental data on kaon photoproduction off a nucleon. The extracted coupling constant is consistent with the SU(3) prediction as well as with the values obtained from the kaon-nucleon scattering process.
STUDI IN SILICO MODIFIKASI POS TRANSLASI DISAIN VAKSIN CHIMERIC BERBASIS VIRUS LIKE PARTICLES HUMAN PAPILLOMAVIRUS DENGAN KAPSID VIRION L1 Tambunan, Usman Sumo Friend; Parikesit, Arli Aditya; Tochary, Theo A.; Sugiono, Dedy
Makara Journal of Science Vol. 11, No. 2
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Computational Study of Post Translation Modification in Chimeric Virus Like Particles Vaccine of Human Papilloma Virus with Virion Capsid L1. The Human Papillomavirus (HPV) infection has a tight correlation with the incidence of cervical cancer. Chimeric virus like particles (cVLP) has been developed as vaccine candidate for preventing cervical cancer. cVLPs are improvement of Virus Like Particles (VLP) by substituting the epitope of L1 HPV -18 and -52 protein to L1 HPV -16 protein. They are ANN1, ANN2, HMM1, and HMM2. The impact of post translation modification will be determined. Based on In Silico study, the dominant post translation modification is glycosylation
NOTE ON THE OCCURRENCE OF PHYTOPLANKTON AND ITS RELATION WITH MASS MORTALITY IN THE JAKARTA BAY, MAY AND NOVEMBER 2004 Thoha, H.; Adnan, Q.; Sidabutar, T.; Sugestiningsih, Sugestiningsih
Makara Journal of Science Vol. 11, No. 2
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There were noted two times (May and November 2004), fish mass mortality occurred in the coast of the Jakarta Bay, killing several species of small and big fishes, crustaceans, eels and molluscs. Phytoplankton blooms in the Jakarta Bay is accelerated by the high input of nutrients, which caused eutropication of the Bay water. Analysis of water sample showed in st 1 (Marina coast) showed that phytoplankton abundance was of 2.9 x 106 cells/l-1 , the common diatom species recorded at that time were: Skeletonema costatum, Thalassiosira mala, Bacteriastrum varians, Chaetoceros pseudocurvisetus, Nitzschia sigma, Coscinodiscus radiatus. Of the which: Skeletonema costatum 1.8 x106 cells/l-1 ; in st. 3 Binaria lake was the most a common diatoms species found in the Jakarta Bay. This species frequently bloom, especially after rainfall, causing no harm to marine life, the second diatoms Thalassiosira mala 2.8 x 106 cells/l-1 (st 4 Carnaval coast), during this decade in more often frequencies. The second largest group was represented by four dinoflagellates species: Prorocentrum micans, Protoperidinium sp., Ceratium furca and Gonyaulax sp., and one species dominated of dinoflagellate Prorocentrum micans 2.3 x 106 cells/l-1 (in the Dadap coast). P. micans is also common species of the Jakarta Bay. Hydrological conditions in May and November 2004 are, temperature 32 – 33 oC, pH 7.76 to 7. 92, Salinity 32 ‰, Dissolved oxygen 3.88 to 4.26 mg/l, Phosphate 0.10 – 0.40 µg-at-P l-1 , Nitrate 0.01 to 0.03 µg-at-N l-1 . The result suggests that phytoplankton distributes in wider areas than expected and monitoring of its occurrence in Indonesian waters is necessary to prevent harmful effects of such bloom.
PENGARUH PENAMBAHAN URASIL DALAM MEDIA FERMENTASI TERHADAP HASIL β-GLUKAN DARI DUA GALUR AGROBACTERIUM Kusmiati, Kusmiati; Tamat, Swasono R.; Nuswantara, Sukma; Muhamad, Salmah
Makara Journal of Science Vol. 11, No. 2
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Influence of Uracil in Fermentation Media on β-Glucan Production by Agrobacterium Radiobacter A 1.5 and Agrobacterium sp. Bro 1.2.1. Optimum β-glucan production can be achieved by an optimum condition in the fermentation media. Uracil, as a precursor of UDP-glucose, may act as a glucose donor in the formation of polysaccharides such as β-glucan. It is expected that addition of certain quantity of uracil into the fermentation media in a suitable growth phase of Agrobacterium radiobacter A 1.5 and Agrobacterium sp. Bro 1.2.1, will significantly increase the β-glucan production. In this investigation, 0.025%; 0.05% or 0.1% of uracil were added into the fermentation media during the logarithmic phase (24 hour) or stationary phase (46 hour) of growth. The β-glucan product was evaluated from the β-glucan (crude) dry-weight and from the β-glucan content. Beta-glucan content was determined as glucose by the Hisamatsu-AOAC and HPLC methods. The highest β-glucan (crude) dry-weight produced by the A. 1.5 was in a medium containg 0.025% uracil (24 hour), whilst by the A. Bro 1.2.1 was in a medium containg 0.1% uracil (46 hour), both higher than control. The highest β-glucan content produced by the A. 1.5 (27.03%) was in a medium containg 0.025% uracil (46 hour), while control produced only 23.28%. The highest β-glucan content produced by the Bro 1.2.1 (29.34%) was in a medium containg 0.025% uracil (24 hour), while control produced only 28.75%. Two-way anova analysis showed that there were no significant influence difference (α = 0,05) from various concentration of uracil in either growth phases, to the yield of β-glucan (crude) dry-weight nor to the β-glucan equivalent glucose content.
SUSCEPTIBILITY MAGNETIC AND HIGH MAGNETIC FIELD ESR MEASUREMENT OF SrCu2 (PO4 )2 Aripin, Aripin; Mitsudo, Mitsudo; Idehara, T.; Mekata, M
Makara Journal of Science Vol. 11, No. 2
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The magnetic susceptibility and high magnetic ESR measurement of SrCu2 (PO4 )2 has been performed at temperatures ranging from 4.2 K to 300 K and 4.2 K to 77 K, respectively. The magnetic susceptibility shows a broad maximum around T = 40 K. The magnetic susceptibility has been interpreted in terms of one-dimensional magnetic systems. The temperature dependence of the magnetic susceptibility indicated a good agreement with 4-spin alternating configuration model. In the ESR measurement, clear electron spin resonance (ESR) was observed. The integrated intensity for 120 and 301 GHz has a broad maximum at around 40 K, which is consistent with the susceptibility result. A quantitative description gives resonance is the first and second triplet excited states of the excitation spectrum of 4-spin alternating chain configuration. The g1 , g2 and g3 values are approximately 2.21 at temperature above 40 K. The g2 dan g3 values have the dependence of temperature under 40 K.
PENGARUH JENIS DAN TEMPERATUR KOAGULAN TERHADAP MORFOLOGI DAN KARAKTERISTIK MEMBRAN SELULOSA ASETAT Radiman, C. L.; Eka, I.
Makara Journal of Science Vol. 11, No. 2
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Effects of type and temperature of coagulant on the morphology and characteristics of cellulose acetate membranes. Cellulose acetate membranes have been made in this work by phase inversion method using 10 wt. % of cellulose acetate, 10 wt. % of formamide and 80 wt. % of acetone. The dope was coagulated in water or 2-propanol at varied temperature ranging between 5 and 25 oC. The characteristics of the obtained membranes were measured by their water flux and rejection towards dextrans with varied molecular mass, while membrane morphology was observed by Scanning Electron Microscope (SEM). The results showed that membranes coagulated in 2-propanol was denser than the ones coagulated in water resulting in higher rejection of dextrans and lower water permeability. Coagulation in lower temperatures decreased the diffusion rate between solvent and non-solvent and the membrane structure was less porous.
X-RAY DIFFRACTION PHASE ANALYSES FOR GRANULATED AND SINTERED CERAMIC MATERIALS Pratapa, Suminar
Makara Journal of Science Vol. 11, No. 2
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One basic problematic aspect in x-ray diffraction phase analysis is microabsorption effect which may arise from the size of the crystallite phases. Complication of the problem may intensify in sintered ceramic materials where milling of the samples is not simple. We report the Rietveld x-ray diffraction phase analysis of MgO-a-Al2O3 powder mixtures with phase content ratio of 1:1 by weight and MgO-Y2O3 sintered ceramic composites with Y2O3 contents of 10%, 20% and 30% by weight. The mixtures were pre-sintered at 1000°C for 2 hours and then milled while the composites were sintered at 1550°C for 3 hours. The phase composition analysis was done using Rietica, a non-commercial Rietveld method-based software. Relative and absolute phase compositions were examined and results showed that there was a significant amount of phase composition bias resulted from the examination. For the powder mixture, milling can reduce microabsorption effect and hence the calculation bias. For the ceramic composite where milling is almost impossible, additional of Y2O3 caused smaller crystallite size of MgO, so that composition bias is smaller in composites with higher Y2O3 content. A mathematical model is proposed to provide more acceptable phase composition results.

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