Judul: Identification of Cross-Equatorial Northerly Surge and Indian Ocean Dipole Phenomenon in Rain Events in West Part of Java
Abstrak: Aliran massa udara yang berasal dari Laut Cina Selatan (LCS) melewati equator dan merambah ke Laut Jawa dan Pulau Jawa bagian Barat dapat menyebabkan peningkatan curah hujan yang dilewatinya, aliran tersebut dapat disebut Cross Equatorial Northerly Surge (CENS). Fenomena CENS bukan satu-satunya penyebab peningkatan atau penurunan curah hujan di Pulau Jawa. Indian Ocean Dipole (IOD) juga dapat menyebabkan perubahan curah hujan di Pulau Jawa. Penelitian ini bertujuan untuk menganalisis pola curah hujan selama kejadian CENS, IOD, dan secara bersamaan. Data yang digunakan pada penelitian ini yaitu data curah hujan lima stasiun pengamatan serta data angin permukaan, Suhu Permukaan Laut (SPL), anomali SPL dan transport kelembaban. Hasil penelitian menunjukkan bahwa peningkatan pola curah hujan yang tinggi di empat stasiun pengamatan selama CENS pada tahun 2004-05, kecuali di Stasiun Geofisika Cemara Bandung. Sementara selama CENS dengan IOD negatif pada tahun 2004 05, peningkatan pola curah hujan terjadi di Stasiun Klimatologi Dramaga Bogor, Meteorologi Kemayoran, dan Meteorologi Kertajati. CENS dengan IOD positif pada tahun 2019 menyebabkan rendahnya curah hujan di lima stasiun pengamatan dibandingkan selama kejadian CENS dan CENS dengan IOD negatif. Meskipun demikian, peran signifikan CENS dalam membawa massa udara lembab dapat mengakibatkan hujan., The airflow originating from the South China Sea (LCS) crosses the equator and extends to the Java Sea and Western Java Island, potentially causing increased rainfall along its path. This flow is referred to as the Cross-Equatorial Northerly Surge (CENS). However, the CENS phenomenon is not the sole factor influencing rainfall variability on Java Island. The Indian Ocean Dipole (IOD) also contributes to changes in rainfall patterns on Java. This study aims to analyze rainfall patterns during occurrences of CENS, IOD, and their combined effects. The data used in this research includes rainfall data from five observation stations, as well as surface wind data, Sea Surface Temperature (SST), SST anomalies, and moisture transport. The results show significant increases in rainfall patterns at four observation stations during CENS in 2004-05, except at the Geophysics Station Cemara Bandung. Meanwhile, during CENS with negative IOD in 2004-05, increased rainfall patterns were observed at the Climatology Station Dramaga Bogor, Meteorology Kemayoran, and Meteorology Kertajati. CENS with positive IOD in 2019 resulted in lower rainfall across the five observation stations compared to the periods of CENS and CENS with negative IOD. Nevertheless, the significant role of CENS in transporting moist air can lead to rainfall.
Keyword: CENS, IOD, Moisture Transport, Rainfall, SST

Judul: Pengaruh Cold Surge dan MJO terhadap Peningkatan Hujan di Indonesia pada Periode East Asian Winter Monsoon
Abstrak: Intensitas curah hujan di Indonesia salah satunya dipengaruhi oleh daya konveksi dan pergerakan angin. Penelitian ini bertujuan untuk menganalisis hubungan antara cold surge dengan fenomena variabilitas iklim intra-musiman Madden-Julian Oscillation (MJO) dalam mempengaruhi peningkatan curah hujan di Indonesia. Data yang digunakan dalam identifikasi cold surge adalah data kecepatan angin meridional menggunakan ERA-Interim. Selain itu, identifikasi MJO dilakukan menggunakan data indeks RMM1 dan RMM2 dari Bureau of Meteorology (BOM). Hasil penelitian menunjukan bahwa terdapat peran cold surge dan MJO dalam mempengaruhi curah hujan di Indonesia. Pada periode East Asian Winter Monsoon (EAWM) tahun 2000-2015, terdapat 362 kejadian cold surge, 186 kejadian MJO, dan 113 kejadian cold surge-MJO. Pengaruh cold surge dapat melewati daerah ekuator dan berpotensi membawa massa uap air yang menyebabkan curah hujan tinggi di lautan Indonesia mencapai 50-75% dari kondisi klimatologis curah hujan periode EAWM. Aktifitas konveksi (MJO) yang bergerak dari barat ke timur juga berperan dalam meningkatkan intensitas curah hujan, namun sebaran curah hujannya lebih luas dibandingkan kejadian cold surge, terutama di Indonesia bagian timur. MJO dan cold surge yang terjadi secara bersamaan dapat meningkatkan curah hujan hingga 100-150%. Meningkatnya curah hujan dapat dijelaskan oleh mekanisme transpor uap air yang tinggi di daerah seperti Laut Jawa dan wilayah pesisir Indonesia. Dampak kejadian cold surge terhadap peningkatan curah hujan di Indonesia memerlukan jeda waktu sekitar 1-2 hari.
Keyword: angin meridional, cold surge, curah hujan, ERA-Interim, Madden-Julian Oscillation

Judul: Synthesis of Chicken Eggshells-Based β-Tricalcium Phosphate Bioceramics and Their Biocompatibility Test as A Tooth Filler
Abstrak: Preservation of alveolar bone following tooth extraction is an important step in dental practices before dental implant placement. This study reported synthesis of β-Tricalcium Phosphate (β-TCP) bioceramics and its biocompatibility test as a tooth filler to maintain the desired alveolar ridge dimension and stimulate the bone healing processes in the area of tooth loss. β-TCP bioceramics was resulted directly from precipitation of calcinated chicken eggshells as calcium source and phosphoric acid. The corresponding β-TCP was mixed with chitosan 2% to get β-TCP pellet for biocompatibility testing. Biocompatibility testing of β-TCP on lower incisor was performed in rabbits and sheep as animal model. In this study, the x-ray diffraction (XRD) profiles showed that 1000 oC calcinated chicken eggshells correspond to calcium oxide (CaO). There was also transformation phase of CaO into Ca(OH)2 observed after more than three months stored. The XRD profiles proved that obtained β-TCP bioceramics by precipitation has the same pattern with that of reference data base and commercial β-TCP. Fourier transform infrared (FTIR) spectra were completely consistent with the result of crystallization processes observed by XRD measurements. Moreover, the purity of the product shown by the atomic absorption spectroscopy (AAS) resulted in Ca/P ratio of 1.48 which was closed to that of standard β-TCP ceramics. The repeatable XRD peaks patterns and FTIR spectra obviously showed the sample reproducibility. Sheep’s alveolar socket that is filled with the corresponding β-TCP demonstrated the expected results. The x-ray radiograph of sheep’s jaw indicated no change on mesio-distal of the edentulous area. Moreover, the histological results were completely consistent with the x-ray radiograph and macroscopic result which is proved by the formation of new bone. In the contrary with sheep’s result, histological results showed no tooth growth on rabbit proved by the presence of lipid and collagen on the extraction site. This result did not correspond to the x-ray radiograph and macroscopic results that demonstrated the tooth growth and erupted tooth. It is clear that the corresponding β-TCP could minimize the bone loss and maintain the dimension of alveolar ridge.
Keyword: β-tricalcium phosphate, chicken eggshells, rabbit, sheep, tooth filler