Judul: Synthesis and In Vitro Test of Porous Hydroxyapatite-Chitosan with Sol Gel Method.
Abstrak: Hidroksiapatit (HAp) memiliki sifat biokompatibilitas yang baik dengan tulang karena memiliki kesamaan komposisi kimia dengan tulang. Salah satu metode sintesis HAp adalah metode sol gel. Metode sol gel dapat digunakan untuk menghasilkan kristal HAp yang baik. HAp berpori dibuat dari kalsium yang diperoleh dari cangkang telur dengan penambahan asam fosfat dan kitosan. Penelitian dilakukan dengan ragam volume larutan kitosan yang ditambahkan, yaitu 30, 40, 50, dan 60 mL. Analisis sampel dilakukan dengan menggunakan difraksi sinar-X (XRD), mikroskop elektron payaran (SEM), dan spektrofotometer serapan atom (AAS). Pencirian dengan XRD terhadap HAp-kitosan yang telah dikalsinasi menunjukkan tidak ada puncak kitosan, hanya terdapat puncak milik HAp. Pencirian dengan SEM menunjukkan bahwa penghilangan kitosan melalui kalsinasi menghasilkan HAp dengan pori berukuran mikro. Uji in vitro menunjukkan bahwa terjadi penurunan konsentrasi kalsium setelah 6 hari perendaman sampel dalam larutan simulated body fluid (SBF). Penurunan ini disebabkan oleh pengendapan ion kalsium pada permukaan HAp berpori untuk membentuk kristal apatit.
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Judul: Sintesis dan Karakterisasi Hidroksiapatit Berpori dengan Porogen Kitosan
Abstrak: This research had been done the synthesis of porous hydroxyapatite (HA) by sol gel method. The precusor calcium using eggshells and H3PO4 as phosphate source. The ratio of HA-chitosan to synthesize porous HA are 90:10, 80:20, 70:30, 60:40, and 50:50 and variation of chitosan size are 0.26 μm and 625.45 μm. The phase and crystaline structure of sample characterized by X-Ray Diffractometer. The porous HA with variation of chitosan A and chitosan B showed the percentage of HA would be rised if researcher added more of chitosan compotition, except HA-chitosan A 80:20, HA-chitosan B 80:20 and 70:30 be decreased, but did effect not for chrystaline size. The functional groups of HA identified by Fourier Transform Infrared Spectroscopy. The functional groups of HA which detected by are OH-, PO43-, and CO32-. The morphological structure of sample analyzed by Scanning Electron Microscopy. The result of sampel HA had shown the porouses structure using chitosan as porogen however it was small about 0.29-0.46 μm with the form of porouses are small cyrcle and the ditribution of porouses are smooth.
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Judul: Prediction Model Development Madden Julian Oscillation (MJO) based on the results of data analysis Real Time Multivariate MJO (RMM1 and RMM2).
Abstrak: Background of this research is the importance of study on the Madden Julian Oscillation, the dominant oscillation in the equator area. MJO cycle showed by cloud cluster growing in the Indian Ocean then moved to the east and form a cycle with a range of 40-50 days and the coverage area from 10N-10S. Method that used to predict RMM is Box-Jenkins based on ARIMA (Autoregressive Integrated Moving Average) statistical analysis. The data used RMM daily data period 1 March 1979 –1 March 2009 (30 years). RMM1 and RMM2 is an index for monitoring MJO. This is based on two empirical orthogonal functions (EOFs) from the combined average zonal 850hPa wind, 200hPa zonal wind, and satellite-observed Outgoing Longwave Radiation (OLR) data. The results in form of the Power Spectral Density (PSD) graph Real Time Multivariate MJO (RMM) and long wave radiation (OLR = Outgoing Longwave Radiation) at the position 100°BT, 120°BT, and 140°BT that show the wave pattern (spectrum pattern) and clearly shows the oscillation periods. There is a close relation between RMM1 with OLR at the position 100oBT that characterized the PSD value about 45 day. Through Box-Jenkins method, the prediction model that close to time series data of RMM1 and RMM2 is ARIMA (2,1,2), that mean the forecasts of RMM data for the future depending on one time previously and the error one time before. Prediction model for RMM1 is Zt = 1.681 Z t-1 – 0.722 Z t-2 + 0.041 Zt-3 - 0.02 at-1 - 0.05 at-2.. Prediction model for RMM2 is Zt = 1.714 Zt-1 – 0.764 Zt-2 - 2 + 0.05 Zt-3 - 0.109 at-1 - 0.05 at- 2.. The flood case in Jakarta January-February 1996 and 2002 are one of real evidence that made the MJO prediction important. MJO with active phase dominant cover almost the entire Indonesia west area at that moment. Keywords: MJO, RMM1 and RMM2, OLR, Power Spectral Density, ARIMA, Rainfall
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