Judul: Evaluation of Topographic Wetness Index and Normalized
Difference Water Index for Identifying Flood-Prone Areas in Ciliwung Watershed
Abstrak: Bencana banjir dapat memberikan dampak besar dan merugikan beberapa wilayah di Indonesia. Salah satu penyebab banjir adalah penutupan lahan dan topografi. Penelitian ini dilakukan untuk mengevaluasi penggunaan Topographic Wetness Index (TWI) dan Normalized Difference Water Index (NDWI) dalam memetakan daerah rawan banjir. Pemetaan kerawanan banjir dilakukan berdasarkan nilai TWI dan NDWI, serta hasil gabungan kedua indeks tersebut yang kemudian dilakukan overlay terhadap jenis tutupan lahan untuk melihat tingkat kebasahan berdasarkan jenis tutupan lahan. Proses random sampling dilakukan untuk melihat tingkat kebasahan masing-masing penutupan lahan secara adil. Hasil penelitian menunjukkan mayoritas tutupan lahan di wilayah kajian memiliki tingkat kebasahan sedang hingga tinggi. Hal tersebut disebabkan oleh topografi yang cenderung landai dan tingkat kerapatan vegetasi yang cenderung sedikit., Flood disasters can have significant and detrimental impacts on several regions in Indonesia. One of the main causes of floods are land use and topography. This study aims to evaluate the use of Topographic Wetness Index (TWI) and Normalized Difference Water Index (NDWI) in mapping flood-prone areas. Flood vulnerability mapping is conducted based on TWI and NDWI values, as well as the combined results of these two indices, which are then overlaid with land cover types to assess moisture levels based on land cover types. Random sampling is performed to assess the moisture levels of each land cover type. The research findings indicate that the majority of land cover types in the study area have moderate to high moisture levels. This is attributed to the relatively flat topography and low vegetation density.
Keyword: banjir, tutupan lahan, topografi, TWI, NDWI

Judul: Evaluation of Potential Flood Hazards Using  Topographic Wetness Index (TWI) Method in Upper Citarum Watershed
Abstrak: Daerah Aliran Sungai (DAS) Citarum Hulu merupakan wilayah yang sering terjadi kejadian banjir. Salah satu upaya untuk mengantisipasi kejadian banjir di masa yang akan datang dapat dilakukan dengan identifikasi dan memetakan wilayah yang berpotensi terkena banjir. Penelitian ini bertujuan untuk mengidentifikasi potensi bahaya banjir berdasarkan pendekatan Topographic WetnessIndex (TWI) di DAS Citarum Hulu. Penelitian ini menggunakan data DEM (Digital Elevation Model) resolusi 8 m sebagai input model TWI. Hasil analisis menunjukkan bahwa nilai TWI pada DAS Citarum Hulu berkisar antara 0 – 30,53 yang didominasi oleh tingkat potensi banjir kelas “rendah” dengan luas 2,35 x 105 hektar (89%), tingkat potensi banjir kelas “menengah” dengan luas sekitar 2,8 x 104 hektar (10,8%), dan tingkat potensi banjir kelas “tinggi” dengan luas sekitar 354 hektar (0,1%). TWI dapat dijadikan sebagai indikator untuk menentukan wilayah potensi banjir sehingga dapat digunakan sebagai referensi pengelolaan wilayah lebih lanjut., The Upper Citarum watershed has experienced a recurrent flood. One of the efforts to anticipate flood events in future, identification and mapping of potential flooding hazard are necessary. This study aims to identify potential flood hazards using the Topographic Wetness Index (TWI) approach in the Upper Citarum watershed. The approach is based on Digital Elevation Model data with a spatial resolution of 8 m. The results showed that TWI value ranges from 0 – 30,53, and most area was in “low” class flood potential (89%). A "medium" class occupied 10,8% and a “high” grade of flood potential with an area of about 354 hectares (0,1%). TWI can be used as an indicator to determine potential flood areas that can be used as regional management assistance in disaster management, especially floods.
Keyword: Flood disaster, area management, hazard identification, early warning system, high resolution DEM

Judul: Synthesis of Apatite - Chitosan Composite Using Duck Eggshell and Chitosan with Temperature and pH Control
Abstrak: Composite of apatite-chitosan was prepared by using chitosan as polymer matrix. Calcium phosphate was prepared from CaO and (NH4)2HPO4, which the ratio Ca : P had to be 1.67. Chitosan is produced by deacetilase from biopolymer chitin. Duck eggshell (95% CaCO3) as starting material was converted to be calcium oxide (CaO) through calcinations with temperature 1000oC for 5 hours. In-situ and ex-situ methods were prepared from apatite and chitosan (dissolved with acetate acid 2%). Calcium phosphate prepared for bone implantation, but it is too fragile and brittle to be implant into the body. So addition of chitosan can decrease crystalinity and increase mechanic characteristic (tougher). Composite apatite-chitosan was resulted by fast precipitation. Fast precipitation was held in a breaker glass with nitrogen atmosphere, under controlled temperature at 37oC and pH 7, in order to increase amount of hydroxyapatite. Precipitation with CaO which was dropped by (NH4)2HPO4. Hydroxyapatite and chitosan were appearing at samples with in-situ and ex-situ methods which indicating by peak matching of XRD (closed lattice parameter, crystal size), overlapping at FTIR spectra and supporting by SEM picture (homogenous and agglomerated particle). However, it still needs further research to examine biocompatibility osteoconductive degree of sample by in-vivo and in-vitro test.
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