Judul: Kajian Pustaka Penyalutan Komposit Hidroksiapatit-TiO2-Kitosan Pada Paduan Logam Stainless Steel Sebagai Material Implan Tulang
Abstrak: Logam stainless steel dalam dunia medis sudah banyak diaplikasikan sebagai material implan tulang, tetapi logam stainless steel tanpa penyalutan oleh biomaterial seperti hidroksiapatit (HAp) akan menimbulkan masalah karena rentan terhadap korosi. HAp juga perlu dikompositkan dengan kitosan dan TiO2 untuk meningkatkan kekuatan mekanik dan sifat antibakterinya agar proses implan tidak menimbulkan masalah seperti infeksi pascaoperasi. Kajian pustaka ini bertujuan mengevaluasi potensi logam stainless steel yang dilapisi komposit HAp-TiO2- kitosan menggunakan metode yang tepat agar memiliki sifat antibakteri dan ketahanan korosi yang baik sehingga dapat biokompatibel di dalam tubuh. Logam stainless steel yang disalutkan dengan komposit berpotensi memiliki sifat antibakteri karena terdapat TiO2 dan kitosan yang mampu menghambat bakteri. Selain itu, penambahan TiO2 dan kitosan dapat meningkatkan ketahanan korosi karena komposit yang tersalut akan membentuk ketebalan lapisan yang merata di permukaan logam. Metode elektroforesis deposisi adalah metode yang tepat dalam penyalutan ini karena menghasilkan lapisan dengan komposisi yang tepat dengan kekuatan adhesi yang baik serta ketebalan yang bervariasi., Stainless steel metal in the medical world has been widely applied as a bone implant material, but stainless steel metal without coating by biomaterials such as hydroxyapatite (HAp) will cause problems because it is susceptible to corrosion. HAp also needs to be composited with chitosan and TiO2 to increase its mechanical strength and antibacterial properties so that the implant process does not cause problems such as postoperative infection. This literature review aims to evaluate the potential of stainless steel coated with HAp-TiO2-chitosan composite using the suitable method to have good antibacterial and corrosion resistance properties to be biocompatible in the body. Stainless steel metal coated with the composite has the potential to have antibacterial properties because there is TiO2 and chitosan which can inhibit bacteria. In addition, the addition of TiO2 and chitosan can improve corrosion resistance because the coated composite will form an even layer thickness on the metal surface. The deposition electrophoresis method is suitable for coating because it produces a layer of the right composition with good adhesion strength and varying thickness.
Keyword: biocompatibility, chitosan, hydroxyapatite, stainless steel, TiO2

Judul: Study of Hydroxyapatite-Chitosan Composites with Various Metal Oxides Coated on Metal Alloys as Implant Materials
Abstrak: Kerusakan tulang yang meningkat membutuhkan sintesis biomaterial sebagai bahan implan. Penelitian ini dilakukan untuk meninjau berbagai referensi mengenai penyalutan komposit HAp-kitosan-logam oksida pada paduan logam. Metode yang baik dan banyak dipilih dalam sintesis HAp-kitosan-logam oksida yakni dengan menggunakan metode presipitasi, ex-situ dan metode elektroforesis deposisi (EPD) sebagai metode penyalutannya. Paduan logam yang tersalut komposit HApkitosan-logam oksida memiliki potensi dalam menghasilkan implan yang mampu menghambat bakteri dan ketahanan korosi secara baik. Komposit HAp-ZnOkitosan memiliki zona hambat paling baik terhadap bakteri E. coli yakni sebesar 8 mm. Zona hambat juga dipengaruhi oleh konsentrasi logam oksida yang ditambahkan. Paduan logam yang telah tersalut komposit menunjukkan ketahanan korosi lebih baik dibandingkan sebelum penyalutan. Logam CoCrMo yang tersalut komposit HAp-kitosan memiliki ketahanan korosi paling baik dibandingkan logam Stainless Steel dan Ti6Al4V dengan nilai laju korosi sebesar 0,0035 mpy., Increased bone destruction requires the synthesis of biomaterials as implant materials. This research was conducted to review various references regarding the coating of HAp-metal oxide-chitosan composites on metal alloys. A good and widely chosen method in the synthesis of HAp-chitosan-metal oxide is by using precipitation, ex-situ and deposition electrophoresis (EPD) methods as coating methods. The metal alloy coated with the HAp-chitosan-metal oxide composite has the potential to produce implants that can inhibit bacteria and have good corrosion resistance. The HAp-ZnO-chitosan composite had the best inhibition zone against E. coli bacteria, which was 8 mm. The zone of inhibition also affects the concentration of added metal oxides. The composite coated alloy showed better corrosion resistance than before coating. CoCrMo metal coated with HAp-chitosan composite has the best corrosion resistance compared to Stainless Steel and Ti6Al4V with a corrosion rate of 0,0035 mpy.
Keyword: alloy, antibacterial, anticorrosion, hydroxyapatite-chitosan, metal oxide

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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