Judul: Distribution model of oil spills along the cruise lane of Kepulauan Seribu, DKI Jakarta
Abstrak: Tanker traffic and oil exploration as well as production activities in offshore areas have been made the Indonesian waters prone to oil spills. As we know that Kepulauan Seribu has multi-functional area such as aquaculture, marine transportation, marine tourism, marine protected areas and international cruise lines, especially tankers. Tankers often cause oil spill in the waters of Kepulauan Seribu. It is able to reduce the environmental condition, cause the impact and economic losses. For that reason it is necessary to increase our knowledge in order to predict the distribution and fate of oil spills. The aims of this study to build a 2D hydrodynamics model to see the patterns of water mass movement of Kepulauan Seribu even on the west monsoon and east of monsoon. The models of oil spills distribution based on the hydrodynamic models can be used as a tool to prevent in Kepulauan Seribu. To control oil spills at sea will be more effective when distribution we have a model of oil spills. The results of this model show that the area exposed to and the duration of exposure by the oil spill occurred in Kepulauan Seribu.Data input used in the model consist of water depth data (bathymetry), wind speed and direction, tidal data, data of the Islands cruise lines, data of tankers types and tanker transport capacity through the territorial waters of Kepulauan Seribu, currents data, and the oil fractions data..The impact of the distribution of oil occurred in the west season almost reaching marine protected areas in the north of the island of Tidung Besar within 15 hours with the distance from the source of the spill of about 10 km and thickness of oil layer is less than 45 mm with duration of exposure between 18-23 hours.Crude oil has the highest duration of exposure reached 326 hours for west monsoon season and 159 hours on the east while gasoline has a very short exposure time of about 70 hours.
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Judul: Model Sebaran Tumpahan Minyak di Perairan Indramayu, Jawa Barat.
Abstrak: Kabupaten Indramayu memiliki wilayah pesisir yang terdiri atas hutan mangrove yang sebagiannya dimanfaatkan untuk perikanan tambak dan perikanan budidaya. Penelitian ini bertujuan untuk mensimulasikan sebaran dan nasib dari minyak yang tumpah serta mengestimasi area yang terkena dampak tumpahan minyak. Lokasi penelitian di perairan Laut Jawa khususnya di perairan Indramayu pada posisi geografis wilayah model adalah105.66o BT sampai 110.51o BT dan 7.27o LS sampai 5.07o LS. Karakteristik minyak didapat dari perpustakaan P.T. Pertamina Unit Pengelolahan VI Balongan sedangkan data angin didapat dari data hasil model ECMWF dan data BMKG pada bulan September 2008. Data pasang surut yang digunakan berasal dari hasil model NAOTIDE National Astronomical Observator dengan data verifikasi berasal dari pengukuran lapang. Model hidrodinamika 2 dimensi untuk membangkitkan data arus menggunakan Estuary, Lake, and Coastal Ocean Model (ELCOM) dengan lebar grid 2000 meter dan time step 2 menit. Hasil model hidrodinamika selama 30 hari menunjukan kecepatan dari 0.01 m/det sampai 0.45 m/det yang dipengaruhi juga oleh bentuk batimetri perairan. Verifikasi hasil model dengan data lapang menunjukan perbedaan amplitudo kurang dari 10 cm sedangkan perbedaan fase kurang dari 2 jam. Model sebaran tumpahan minyak dengan menggunakan General NOAA Oil Modelling Environment (GNOME) mampu memprediksi jumlah minyak yang tumpah sebanyak 25565 barrel selama 6 jam dengan lama simulasi adalah 15 hari pada bulan September 2008. Secara umum pola sebaran tumpahan minyak menuju ke Barat Laut dengan luas maksimal 691.54 km2. Intensitas keberadaan minyak berdasarkan model Automated Data Inquiry for Oil Spills (ADIOS 2) menunjukkan bahwa ketersediaan minya di perairan mencapai 71.3% minyak residu selama 5 hari.
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Judul: Sintesis Paduan Ti-6Al-4Nb sebagai Matrial Implan Pengganti Komponen Tibial
Abstrak: Synthesis of Ti-6Al-4Nb alloy was done by melting using Tri Arc Melting Furnace. Each sample was remelted five times to ensure the homogenity. Aluminum and niobium addition were expected to stabilize α phase and β phase until the αβ-titanium alloy was resulted. Yet based on the experiment, it was α-titanium alloy resulted. α-titanium alloy was a Hexagonal Close Packed (HCP) crystalline structure which would be cracked if deformation non-uniaxial happens. The presence of oxygen in pure titanium significantly increased the hardness of titanium. The addition of aluminum was also able to increase the hardness of titanium alloy because aluminum more stabilize the α phase in the α-titanium alloy. The corrosion ressistance of titanium could be increased by adding aluminum and niobium. Titanium coating with HA/chitosan composite was also proved in decreasing the corrosion rate because it barried direct interaction between titanium alloy and corrotion solution.
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