Judul: Investigating the Teleconnection Impacts of MJO Air-Sea Interactions using a Moist Linear Baroclinic Model
Abstrak: Fenomena MJO mempengaruhi kondisi suhu permukaan laut di tropis. Interaksi dari Atmosfer-laut tersebut mempunyai pengaruh terhadap cuaca di Lintang Tengah melalui dinamika Atmosfer. Simulasi dampak telekoneksi MJO dapat dilakukan dengan menggunakan model linear baroklinik kering dan basah. Penelitian ini bertujuan memahami dampak dan mekanisme telekoneksi dari Interaksi Atmosfer-laut MJO di Sirkulasi lintang Tengah. Penelitian ini juga bertujuan mengevaluasi kemampuan model linear baroklinik basah dalam melakukan simulasi pola telekoneksi MJO dan membandingkannya dengan model linear baroklinik kering. Interaksi Atmosfer-laut MJO dipengaruhi oleh awan konveksi MJO dan pertukaran panas permukaan laut akibat dari aktivitas pergerakan konveksi. Pengaruh MJO terhadap SST mempunyai jeda waktu hingga 10 hari setelah fase MJO aktif terjadi. Simulasi dampak MJO menggunakan model linear baroklinik kering dan basah menunjukkan hasil pola anomali ketinggian geopotensial yang sama. Model basah menunjukkan pola hasil dampak telekoneksi yang mendekati dengan hasil data observasi dibandingkan dengan model kering., The MJO phenomenon affected tropical sea surface temperature conditions. This atmosphere-ocean relationship has an influence on weather in middle latitudes through atmospheric dynamics. Simulations of the impact of the MJO teleconnection can be carried out using dry and moist linear baroclinic models. This research aims to understand the influence and teleconnection mechanisms of MJO atmosphere-ocean interactions in the mid-latitude circulation. This research also aims to evaluate the ability of the Moist Linear Baroclinic Model (MLBM) in simulating MJO teleconnection patterns and compare it with dry LBM. The MJO atmosphere-ocean interaction is influenced by MJO convection cloud and sea surface heat exchange resulting from convection movement activity. The influence of the MJO on SST has a time lag of up to 10 days after the active MJO phase occurs. Simulations of the MJO impact using the LBM dry and wet models show quite similar geopotential height anomaly patterns. The moist model results have a pattern that is closer to the observation results compared to the dry linear baroclinic model.
Keyword: Heat Budget, MJO, Sea Surface Temperature, Teleconnection, Moist Linear Baroclinic Model

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: Hydroxyapatite-Chitosan Composite Coating on Stainless Steel 316 to Improve Corrosion Resistance
Abstrak: Metals that were used in bone implantation should have good corrosion resistance that were not easily corroded when implanted into the body. Metal corrosion resistance of stainless steel 316 can be enhanced through the metal coating by hydroxyapatite-chitosan composite with composition ratio of hydroxyapatite (gram) and chitosan 3% (mL) 0.2:0, 0.2:0.1, 0.2:0.5, 0.2:1.0, and 0.2:1.5. Besides improving the corrosion resistance of metal, the presence of chitosan also maintain the position of hydroxyapatite on metal surfaces. Corrosion resistance increases with increasing amount of chitosan added and the best composition of hydroxyapatite-chitosan composite was 0.2:1.0.
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