Judul: Peugaruh Nisbah Selulosa Dengan Asetat Anhidrida dan Lama Asetilasi Terhadap Produksi Selulosa Asetat dari Selulosa Mikrobial
Abstrak: Selulosa mikrobial merupakan salah satu produk metabolit dari mikroorganisme genus Acetobaeter, Agrobacterium. Rhizobium. Sarcina dan Valonia. Pada saat ini Acelobacler rylinum yang kemudian diklasifikasi ulang sebagai Gluconocetobacter xylinus merupakan mikroorganisme yang umum digunakan untuk memproduksi selulosa mikrobial. Selulosa mikrobial memiliki memiliki komposisi kimia yang sama deugan selulosa tanaman, tetapi memiliki perbedaan pada strnktur tiga dimeusi , derajat polimerisasi (biasanya berkisar antara 2000-6000), dan sifat fisikokirnianya
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Judul: Identifikasi isolat acetobacter sp. lokal dan uji kemampuannya dalam memeproduksi selulosa pada medium HS (hestrin dan schramm) dan modifikasinya
Abstrak: Selulosa yarg dihasilkan dari tumbuhan dikenal dengan lignoselulosa, sedangkan selulosa yang dihasilkan oleh bakteri disebut selulosa bakteri (Bacterial cellulose). Dewasa ini telah mulai dilakukan pengembangan produksi selulosa dari bakteri yang dihasilkan oleh kelompok bakteri tertentu terutama dari genus Acetobacter. Selulosa bakteri terbebas dari kontaminasi polisakarida-polisakarida lainnya dan isolasi serta permurniannya relatif sederhana, tidak memerlukan energi atau proses kimiawi yang rumit. Selulosa bakteri mempunyai sifat-sifat fisik yang unik, diantaranya jaringan serat yang ultra halus, struktur jaringan yang kuat, kemurnian dan kristalinitas yang tinggi, serta bersifat biodegradable. Alternatif penggunaannya antara lain sebagai bahan baku produksi kertas bermutu tinggi, makanan rendah kalori dan membran ultrafiltrasi. Penelitian iri bertujuan untuk memperoleh isolat Acetobacter lokal yang unggul dalam memperoduksi selulosa dengan melakukan isolasi dan identifikasi, serta memperoleh komposisi media yang optimal untuk produksi selulosa menggunakan isolat lokal tersebut. Media yang digunakan pada tahap produksi adalah medium HS (Hestrin dan Schramm) dan medium HS yang dimodifikasi berdasarkan hasil analisis komposisi air kelapa. Penggunaan media sintetik ini dimaksudkan untuk menghindari ketergantungan terhadap persediaan media alami seperti air kelapa. Perolehan selulosa yang dihasilkan pada media HS termodifikasi diharapkan lebih tinggi daripada perolehan selulosa pada medium HS...
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Judul: Characteristic of Overshooting Top (OT) Based on  Himawari  8  Satellite  as  a  Convective  Cloud  Feature  that  Generates  Extreme Weather in the Java Island Region
Abstrak: Overshooting Top (OT) is a feature at the top of a convective cloud that is associated with extreme weather. Research on OT in tropical Indonesia is still very limited. The existence of geostationary satellites with wide area coverage and fast frequency observations is useful for observing the fast dynamics of the OT life cycle. Therefore, this study intends to analyze the relationship between OT and extreme weather, updraft and thermodynamic conditions of OT when extreme weather occurs, the best objective method for detecting OT in the day time and night time, and the spatiotemporal distribution of OT in the tropical region of Java Island during the 2018-2021 period. Based on visual analysis using visible channel and Himawari 8 sandwich products, 87% of extreme weather events in Java were accompanied by the appearance of OT. It indicates that the presence of the OT pattern is a convection cloud pattern or feature that is closely related to extreme weather events for the Java Island region. The existence of a time lag between the appearance of OT and extreme weather events on Java Island indicates that the OT of convection cloud can be used as a precursor or nowcasting for the appearance of extreme weather. Most of the convective cloud OT features during extreme weather events on Java Island have altitude that were only able to exceed the altitude of the equilibrium level and few were able to exceed the tropopause level of 9 km – 16 km. The difference in atmospheric conditions during extreme weather events on Java Island, which is in the tropics and subtropics, is a strong and unstable convective energy condition characterized by a larger CAPE, as well as unstable KI, LI, SI and TTI values. It is offset by kinematic factors in the form of a weak vertical wind shear (bulk wind shear 0-6 km) and a higher freezing point height. The difference between extreme weather events in the Java Island region and other tropical regions compared to subtropical regions is the strong updraft speed of convection clouds. The IRW Texture COMB algorithm based on the IRW-Texture Gradient modification and the COMB algorithm shows a significant increase in quality for detecting OT and non-OT pixels in Java. Rainy days with rainfall > 50 mm/day are very common in areas with an altitude of > 500 m. On the other hand, the level of convection activity which is indicated by the presence of OT and lightning is significantly reduced in this area. OT of convective clouds appear more frequently during the DJF season and less frequently during the JJA season. OT often appears during the day time and rarely at night time. Most OTs appear in the central part, away from the south and north coasts of Java Island during the day, while OTs that appear near the south and north coasts of Java Island can appear in the morning or afternoon.
Keyword: convective clouds, extreme weather, Overshooting Tops, Himawari 8 Satellite