Judul: Pola Curah Hujan Empat Kota Besar di Indonesia dan Kaitannya dengan Kejadian El Nino Southern Oscillation (ENSO)
Abstrak: Variabilitas curah hujan di Indonesia sangat beragam yang menyebabkan intensitas curah hujan dibeberapa kota besar di Indonesia sangat bervariasi. Terjadinya ENSO menyebabkan perubahan kondisi intensitas curah hujan di berbagai wilayah termasuk beberapa kota besar di Indonesia. Tujuan penelitian ini adalah Mengidentifikasi intensitas curah hujan bulanan dan tahunan di empat wilayah kota besar di Indonesia dan kaitannya dengan kejadian ENSO. Pengolahan data dilakukan untuk mengetahui persentase kondisi bulan basah, lembab, dan kering setiap tahunnya serta untuk mengetahui data curah hujan tahunan. Hasil yang diperoleh pada wilayah Bogor dengan persentase bulan basah memiliki rata-rata curah hujan diatas 70 % dan menjadi wilayah dengan persentase bulan basah tertinggi, sedangkan Surabaya menjadi wilayah dengan intensitas curah hujan terendah. Pada kondisi ENSO curah hujan yang turun di wilayah Bogor dan Makassar sama-sama memiliki nilai tertinggi pada masing-masing tahun pengamatan. Secara keseluruhan, wilayah Bogor memiliki nilai curah hujan tahunan tertinggi hampir setiap tahunnya. Hal ini mengindikasikan kondisi curah hujan wilayah Bogor tidak terlalu dipengaruhi oleh kondisi ENSO dan menjadi wilayah dengan curah hujan yang stabil setiap tahunnya.
Keyword: ENSO, rainfall intensity, Bogor area, climatic classification

Judul: Analisis Variabilitas Curah Hujan Indonesia pada Kejadian ENSO
Abstrak: Indonesia is one of the countries which experiences El Niño and Southern Oscillation (ENSO) impact on rainfall variability. The purpose of this study included to investigate the Indonesian climate variations related to ENSO events and to understand the effect of ENSO on rainfall temporal distributions at Indramayu (6.35°LS, 108.32°BT) and Tabing (0.88°LS, 100.35°BT). Composite analysis method was used to reveal the trend of sea surface temperature anomaly, wind at 850 hPa, OLR and TRMM 3B43 rainfall data, whereas temporal and correlation analysis was used to observe rainfall and nino-3.4 index. When El Niño sea surface temperature anomaly (ASPL) maximum in October-December, 850 hPa wind backwards from west to east along with increased speed and deviation of OLR below the average values in central and eastern equatorial Pacific which indicates the accumulation of rain cloud. La Niña occurrence is indicated by the deviations of sea surface temperature below average. Low pressure center in Asia reached 850 hPa winds and strengthened Walker circulation, the movement of the air mass brought moisture to Indonesia. Based on the composite of TRMM rainfall, it appeared that the El Niño events gave more significant impact at the end of the year (October to December) on East Indonesia, Java and parts of Sumatra and Kalimantan, while La Niña (December to February) in south and eastern part of Indonesia. Monsoonal pattern (Indramayu) showed ENSO impacts more strongly than equatorial (Tabing). The shift of dry season and low rainfall were affected by ASPL fluctuations on nino-3.4 region.
Keyword: TRMM, SPL, Rainfall, OLR, ENSO

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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