Judul: Study of Hydroxyapatite-ZnO-Chitosan Composite Coating on CoCrMo Metal Alloys with Deposition Electrophoresis Method as Antibacterial Implant.
Abstrak: Kinerja osseointegrasi paduan logam CoCrMo yang relatif rendah sebagai implan dapat menimbulkan adanya infeksi sehingga menunda pemulihan pascaoperasi. Salah satu cara pencegahan infeksi tersebut, yaitu menambahkan komposit HAp-ZnO-kitosan yang memiliki efek antibakteri. Efek antibakteri berasal dari kemampuan kitosan dan ZnO dalam menghambat pertumbuhan bakteri. Selain itu, penambahan HAp-kitosan pada komposit juga dapat meningkatkan ketahanan korosi pada implan karena bersifat biokompatibel. Telaah pustaka ini bertujuan meninjau berbagai kajian pustaka mengenai penyalutan komposit HAp-ZnO-kitosan pada logam CoCrMo dengan metode elektroforesis deposisi (EPD) dalam meningkatkan sifat antibakteri dan ketahanan korosi pada implan. Laju korosi menurun setelah proses penyalutan sebesar 0,0035 mpy karena adanya penambahan jumlah kitosan optimum sehingga hasil deposisi yang terbentuk lebih baik. Bakteri gram positif memiliki zona hambat yang lebih luas dibandingkan gram negatif akibat penambahan kitosan dan ZnO yang dapat merusak dinding sel bakteri dengan berbagai mekanisme penghambatan., The relatively low osseointegration performance of CoCrMo metal alloys as implants can cause infection and delay postoperative recovery. One way to prevent this infection is to add a HAp-ZnO-chitosan composite which has an antibacterial effect. The antibacterial effect comes from the ability of chitosan and ZnO to inhibit bacterial growth. Moreover, the addition of HAp-chitosan to the composite can also increase the corrosion resistance of the implant because of its biocompatibility. This study aims to review various literature studies regarding the coating of HAp-ZnO-chitosan composites on CoCrMo metal by deposition electrophoresis (EPD) method in improving the antibacterial properties and corrosion resistance of implants. The corrosion rate decreased after the coating process up to 0,0035 mpy due to the addition of the optimum amount of chitosan so that the deposition results formed became better. Gram-positive bacteria have a wider inhibition zone than gram-negative bacteria due to the addition of chitosan and ZnO which can damage the bacterial cell wall with various inhibitory mechanisms.
Keyword: antibacterial, chitosan, CoCrMo, hydroxyapatite, ZnO

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: Utilization of terra/MODIS L1B data for analysis of horizontal wind profile in the troposphere
Abstrak: This study was concerned with horizontal wind derived from data collected with the Moderate-resolution Imaging Spectroradiometer (MODIS) on board the NASA’s Earth Observation System (EOS)-Terra satellite. The aim of this study is to develop a method for the estimation of horizontal wind movement in the troposphere based on Navier-Stokes equation. The method was applied to a calibrated and geolocated Terra/MODIS L1B 1 km data set. The data inputs to estimate surface temperature are retrieved from TIR (Thermal Infrared) bands 31 (10.780 μm to 11.280 μm) and 32 (11.770 μm to 12.270 μm). The obtained surface temperatures were later used to approximate geopotential height on a constant-pressure surface by using the modified Poisson equation. The main assumptions used are the hydrostatic equilibrium, ideal gas law, constant lapse rate and constant acceleration of gravity. Based on the distribution of geopotential height, the pressure gradient force is measured by the gradient of geopotential on an isobaric coordinate to present the horizontal wind profile. For certain topographic areas especially in the mountain ranges, there was a disadvantage of using pressure as a vertical coordinate which lead to inaccuracy. In spite of that, Terra/MODIS L1B data with 1 km spatial resolution can be used to estimate the horizontal wind movement in the troposphere.
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