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.
Keyword: 

Judul: Coastal Circulation and Trajectory Analysis of Water Particles Related to Oil Spill in the North Coastal Waters of Karawang
Abstrak: Perairan Pantai Utara Karawang adalah bagian dari Laut Jawa yang dipengaruhi oleh variabilitas muson. Sehingga interaksi antara muson dengan sirkulasi permukaan laut perairan Karawang diduga dapat mempengaruhi pola distribusi pencemar, terutama berkaitan dengan kejadian tumpahan minyak di perairan Karawang. Tujuan penelitian ini membangun model sirkulasi menggunakan CROCO, serta menganalisis pola sirkulasi dan trajektori partikel massa air sebagai tahap awal analisis tumpahan minyak. Penentuan titik keluaran tumpahan minyak menggunakan citra Sentinel-1A. Metode analisis data dengan Diagram Taylor, deret-waktu, klimatologi, sirkulasi permukaan laut, serta analisis trajektori menggunakan Ichthyop. Model yang dibangun dengan resolusi 1/96º (±1.159 km), dengan validasi SST, SSH, dan komponen arus (zonal dan meridional) menunjukkan korelasi yang tinggi (0.86, 0.87, 0.96, 0.91). Hasil penelitian menunjukkan tren kenaikan suhu terjadi di musim peralihan 1 dan 2 dan terendah di muson timur. Tren salinitas meningkat dari Februari-Oktober dan menurun dari November-Februari. Selama muson barat, pola sirkulasi air laut bergerak dari barat menuju timur dan mulai berbalik arah pada bulan April. Memasuki muson timur pola sirkulasi bergerak dari timur menuju barat. Dominansi arah arus ini juga ditemukan di musim peralihan 2. Hasil model CROCO digunakan untuk analisis trajektori partikel massa air dengan Ichthyop menunjukkan pergerakan partikel yang sesuai dengan arus yang terjadi pada bulan Juli, dimana secara keseluruhan pergerakan partikel didominasi pergerakan dari arah timur menuju barat dan mengikuti kontur topografi Pantai Utara Jawa., The waters of the North Coast of Karawang are part of the Java Sea which is influenced by monsoon variability. Thus, the interaction between monsoons and sea surface circulation in Karawang waters is expected to affect the distribution pattern of polluted materials, especially related to the oil spill event in Karawang waters. The objective of this study is to build circulation model using CROCO and analyze the circulation pattern and water mass trajectory as the preliminary stage of oil spill analysis. The released point of the oil spill is determined using Sentinel-1A imagery. Data analysis method using Taylor Diagrams, time series, climatology, sea surface circulation, and trajectory analysis using Ichthyop. This model used 1/96º resolution (±1.159 km), where SST, SSH, and current components validation showed high correlation (0.86, 0.87, 0.96, 0.91). The results showed that the trend of temperature is increased during monsoon breaks 1 and 2 while the lowest occurred in the southeast monsoon. The trend of salinity increased from February-October and decreased from November-February. During the northwest monsoon, the seawater circulation pattern moves from west to east and begins to reverse in April. Entering the southeast monsoon, the circulation pattern moves from east to west. The results of the CROCO model used for the analysis of water mass particle trajectories with Ichthyop showed that the particle movement corresponds to the current that occurred in July, where overall particle movement is dominated by current movement from east to west and through contours of the north coast of Java.
Keyword: the Java Sea, Ocean circulation, CROCO, Ichthyop, Trajectory, Oil spill

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.
Keyword: