Judul: Dampak QBO terhadap Curah Hujan yang Dipengaruhi oleh MJO di Indonesia.
Abstrak: QBO memiliki hubungan yang kuat dengan MJO di wilayah tropis selama musim dingin di belahan bumi utara (BBU). Frekuensi dan jumlah hari MJO lebih tinggi ketika fase timuran QBO (QBOE) dibanding fase baratannya (QBOW). Meskipun, QBO dan MJO terhubung erat, tetapi dampak QBO terhadap curah hujan belum diketahui. Penelitian ini dilakukan untuk menganalisis dampak fase – fase QBO terhadap curah hujan saat MJO aktif di Indonesia. Fase QBO ditentukan menggunakan anomali kecepatan angin zonal 50 hPa sedangkan fase MJO ditentukan menggunakan real-time multivariate index (RMMI ). Curah hujan dari TRMMv7 digunakan untuk menganalisis dampak QBO terhadap curah hujan MJO. Total kolom uap air, suhu 100 hPa, dan angin vertikal digunakan untuk menganalisis hubungan QBO-MJO terhadap variabilitas curah hujan. Untuk mengisolasi sinyal MJO, digunakan band-pass filter. Aktivitas konveksi MJO yang dianalisis menggunakan outgoing longwave radiation (OLR) menunjukkan amplitudo lebih besar saat QBOE dibanding QBOW. Sejalan dengan hal tersebut, anomali curah hujan harian meningkat (menurun) hingga 3,3 mm/hari (1,8 mm/hari) dan adanya propagasi ke timur yang lebih (kurang) jelas saat QBOE (QBOW). Selain itu, saat QBOE (QBOW) perubahan peluang curah hujan ekstrem meningkat (menurun) hingga 100% (70%) dan tersebar lebih tinggi (rendah) selama fase basah MJO. Suhu tropopause lebih dingin (hangat), distribusi luas (sempit) dari total kolom uap air, dan vertikal adveksi ke atas (ke bawah) teramati terjadi saat QBOE (QBOW). Pengamatan tersebut mengarah pada adanya konveksi skala besar yang lebih kuat (lemah) dan peningkatan (penurunan) intensitas curah hujan dan peluang curah hujan ekstrem.
Keyword: curah hujan, fase baratan QBO, fase timuran QBO, Indonesia, MJO.

Judul: Unravelling the Extratropical Response to MJO Under Different Phases of QBO Using Linear Baroclinic Model (LBM)
Abstrak: Interaksi antara proses Madden-Julian Oscillation (MJO) yang dipengaruhi Quasi-Biennial Oscillation (QBO) dapat mempengaruhi kondisi atmosfer ekstratropis melalui perbedaan dinamika atmosfer. Hubungan MJO-QBO menunjukkan kekuatan amplitudo MJO akan lebih lemah saat fase baratan QBO (W-QBO) dibanding fase timuran (E-QBO). Penelitian ini bertujuan menganalisis dan memahami mekanisme respon ekstratropis terhadap kejadian MJO saat E-QBO dan W-QBO yang kaitannya dengan telekoneksi ke wilayah ekstratropis menggunakan linear baroclinic model (LBM). Penentuan karakteristik MJO saat kejadian QBO menggunakan parameter outgoing longwave radiation berdasarkan fase MJO-QBO yang telah dibentuk. Analisis perambatan sinyal MJO saat QBO dilihat berdasarkan anomali ketinggian geopotensial data observasi dan hasil LBM. Perambatan MJO terhadap QBO memberikan dampak pada kekuatan aktivitas konvektif yang menghasilkan pemanasan diabatik dan dikonversi menjadi forcing untuk menjalankan model. Berdasarkan kedua fase QBO, aktivitas konveksi lebih kuat terjadi saat E-QBO sehingga pemanasan dan pembentukan awan lebih sering terjadi. E-QBO memiliki hasil telekoneksi MJO lebih kuat yang ditunjukkan dengan adanya anomali ketinggian geopotensial yang membentuk sistem tekanan tinggi dan rendah di wilayah Pasifik. Respon belahan bumi utara menunjukkan adanya gangguan saat 2 minggu setelah fase MJO pada setiap fase QBO. Hasil model dan observasi cukup berbeda sehingga perlu dinamika nonlinier untuk meningkatkan aspek respon telekoneksi terhadap wilayah ekstratropis., The interaction between Madden-Julian Oscillation (MJO) and Quasi-Biennial Oscillation (QBO) processes can have an impact on extratropical atmospheric conditions through differences in atmospheric dynamics. The MJO-QBO relationship indicates that the amplitude of the MJO will be weaker during the westward phase of the QBO (W-QBO) compared to the eastward phase (E-QBO). This study aims to analyze and understand the extratropical response mechanism to MJO events during E-QBO and W-QBO phases, which are related to teleconnections to extratropical regions using a linear baroclinic model (LBM). The MJO characteristics during QBO events were determined using the outgoing longwave radiation parameter based on the established MJO-QBO phase. The propagation analysis of MJO signals during QBO was based on geopotential height anomalies from observation data and LBM results. The propagation of MJO to QBO has an impact on the strength of convective activity, which generates diabatic heating and is converted into forcing to run the model. Based on both QBO phases, convective activity is stronger during E-QBO, so heating and cloud formation occur more frequently. E-QBO has a stronger MJO teleconnection result, indicated by geopotential height anomalies that form high and low-pressure systems in the Pacific region. The Northern Hemisphere's response shows disturbances two weeks after the MJO phase in each QBO phase. The model and observational results are quite different, indicating the need for nonlinear dynamics to improve teleconnection response aspects to extratropical regions.
Keyword: teleconnection, Madden-Julian Oscillation, Quasi-Biennial Oscillation, Linear Baroclinic Model, diabatic heating, geopotential height, extratropical response

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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