Judul: Synthesis and Characterization of Fluorapatite Based on Golden Snail Shell with Precipitation and Solid-State Reaction Method
Abstrak: Pemasangan implan sebagai benda asing dalam tubuh sering kali mengalami reaksi penolakan oleh tubuh. Hal tersebut dapat dihindari melalui pelapisan implan dengan fluorapatit (FAp). Salah satu faktor keberhasilan sintesis FAp ditentukan oleh metode sintesis. Penelitian ini bertujuan menyintesis FAp dengan metode presipitasi (FAp-P) dan solid-state reaction (FAp-SS) berbahan dasar cangkang keong emas. Penelitian dilakukan melalui tiga tahap, yaitu preparasi sampel, sintesis FAp, dan karakterisasi FAp dengan X-ray diffraction (XRD), fourier transform infrared (FTIR), dan scanning electron microscope-energy dispersive X-ray (SEM-EDX). Hasil XRD menunjukkan kristalinitas yang baik untuk kedua metode. FAp-SS menghasilkan spektrum FTIR yang lebih mirip dengan spektrum FAp dibandingkan dengan FAp-P. Hasil SEM menunjukkan morfologi sampel FAp-SS lebih seragam dibandingkan FAp-P. Di samping itu, EDX mengonfirmasi rasio Ca/P dari FAp-P sebesar 1,84 dengan P/F 2,00 sedangkan rasio Ca/P dari FAp-SS sebesar 1,86 dengan P/F 2,94. Hasil tersebut mengonfirmasi metode solid-state reaction lebih mendekati standar FAp, yaitu Ca/P 1,67 dan P/F 3,00., Implant placement as a foreign object in the body often experiences a rejection reaction by the body. It can be avoided through implant coating with fluorapatite (FAp). One factor that determines FAp's successful synthesis is the synthesis method. This study aims to synthesize FAp by precipitation method (FAp-P) and solid-state reaction (FAp-SS) made from golden snail shells. The research was conducted through three stages, which are sample preparation, FAp synthesis, and FAp characterization with X-ray diffraction (XRD), Fourier transform infrared (FTIR), and scanning electron microscope-energy dispersive X-ray (SEM-EDX). XRD results showed good crystallinity for both methods. FAp-SS produced an FTIR spectrum that was more similar to the FAp spectrum compared to FAp-P. SEM results showed that the morphology of FAp-SS was more uniform than FAp-P. In addition, EDX confirmed that the Ca/P ratio of FAp-P was 1.84 with a P/F of 2.00, while the Ca/P ratio of FAp-SS was 1.86 with a P/F of 2.94. These results confirm that the solid-state reaction method is closer to the FAp standard, namely Ca/P 1.67 and P/F 3.00.
Keyword: cangkang keong emas, fluorapatit, presipitasi, solid-state reaction

Judul: Synthesis and Characterization of Fluorapatite with Variations in Sintering Temperature Based on Rice Snail Shells Using the Precipitation Method
Abstrak: Kerusakan pada gigi merupakan salah satu contoh kurangnya unsur kalsium pada tubuh kita, karena kalsium berperan dalam perkembangan tulang dan gigi. Cangkang keong sawah dapat digunakan sebagai prekursor untuk pembentukan fluorapatit (FAp). Penelitian ini bertujuan menyintesis dan mengkarakterisasi FAp dari cangkang keong sawah dengan metode presipitasi serta mengetahui pengaruh variasi suhu sintering. Metode penelitian ini dilakukan melalui tahapan preparasi cangkang keong sawah, Sintesis FAp dengan variasi suhu sintering (600 °C, 800 °C, dan 1000 °C) dengan metode presipitasi. Hasil sintesis FAp dikarakterisasi dengan X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR) serta Scanning Electron Microscope Energy Dispersive X-Ray (SEM-EDX). Hasil penelitian menunjukkan bahwa fluorapatit yang disintering dengan suhu 1000 °C memiliki nilai kristalinitas yang paling tinggi berdasarkan hasil XRD. Spektrum FTIR dari FAp suhu 1000 °C diidentifikasi memiliki gugus -OH, OH-F, dan -PO43-. Hasil analisis SEM-EDX menunjukkan fluorapatit dengan suhu 1000 °C memiliki bentuk seperti batang dan jarum serta memiliki rasio molaritas Ca/P sebesar 13,18 dan P/F sebesar 4,29., Synthesis and Characterization of Fluorapatite with Variations in Sintering Temperature Based on Rice Snail Shells Using the Precipitation Method. Supervised by IRMA HERAWATI SUPARTO and CHARLENA Tooth decay is an example of a lack of calcium in our bodies, because calcium plays a role in the development of bones and teeth. Rice snail shells can be used as a precursor for forming fluorapatite (FAp). This study aims to synthesize and characterize FAp from rice field snail shells using the precipitation method and to determine the effect of variations in sintering temperature. This research method was carried out through the stages of preparation of rice snail shells, FAp synthesis with various sintering temperatures (600 °C, 800 °C, and 1000 °C) with the precipitation method. The results of the FAp synthesis were characterized by X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR) and Scanning Electron Microscope Energy Dispersive X-Ray (SEM-EDX). The results showed that fluorapatite sintered at 1000 °C had the highest crystallinity value based on XRD results. The FTIR spectrum of FAp at 1000 °C was identified as having -OH, OH-F, and -PO43- groups. The results of SEM-EDX analysis showed that fluorapatite at a temperature of 1000 °C had a shape like rods and needles and had a Ca/P molarity ratio of 13.18 and P/F of 4.29.
Keyword: Fluorapatite, Crystallinity, Precipitation, Rice Fields Snail Shell

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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