Judul: Biodegradasi Bioplastik Poli-B-Hidroksialkanoat dengan Bahan Pemlastis Tributil Fosfat Pada Media Pendegradasi Padat dan Cair Buatan
Abstrak: Kebutuhan plastik sebagai bahan pengemas dan tahun ke tahun semakin meningkat. Plastik yang banyak beredar saat ini sebagian besar berbahan baku petrokimla dan sangat sulit terdegradasi di alam. Seiring dengan kemajuan ilmu dan teknologi, banyak penelitian telah dilakukan dalam rangka mencari sumber-sumber plastik yang terbarukan (renewable resources). Bioplastik merupakan plastik yang diperoleh dari hasil sintesis oleh mikroorganisme telah banyak menarik perhatian para ilmuwan maupun industri lebih dari satu dasawarsa ini. Beberapa sisi yang menjadi daya tarik tersebut antara lain bahwa bioplastik dapat terdegradasi seluruhnya oleh mikroorganisme air dan tanah, bahan baku yang tidak dibatasi ketersediaannya di alam, dan penggunaan limbah organik sebagai substrat dalam proses pembuatannya sebagai bentuk usaha untuk mengurangi pencemaran lingkungan dan menurunkan biaya produksi bioplastik yang tinggi. Poli-B-Hidroksialkanoat (PHA) merupakan salah satu bioplastik yang dapat diakurnulasi oleh mikroorganisme. PHA yang beredar dipasaran banyak diproduksi menggunakan glukosa sebagai bahan substrat kultivasinya. Kemiripan sifat-sifatnya dengan polipropilen serta banyaknya mikroorganisme yang dapat mengakumulasi, menjadikan PHA sebagai salah satu bioplastik yang memiliki masa depan cerah.
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Judul: Kajian Biodegradasi Bioplastik Poli-B-Hidroksialkanoat dengan Penambahan Pemlastis Dimetil Ftalat dan Dietil Glikol dalam Media Padat Buatan
Abstrak: Pengembangan dan penelitian plastik yang terbuat dari bahan-bahan yang dapat didegradasi oleh mikroorganisme masih terus dilakukan hingga saat ini. Produksi Poly-B-Hydroxyalkanoate melalui penumbuhan mikroorganisme Ralstonia eutropha menggunakan substrat hidrolisat minyak sawit dan bioplastik yang terbuat dari bahan PHA dengan penambaban pemlastis dimetil ftalat dan dietil glikol telah diteliti. Penambahan pemlastis pada bahan polimer mengakibatkan terjadinya modifikasi pada susunan tiga dimensi molekul, meningkatkan mobilitas rantai, menurunkan gaya tarik intermolekul dan Tg (glass transition temperature) bahan amorph (Cuq, 1997). Penelitian ini bertujuan untuk mengetahui pengaruh penambahan pemlastis dimetil ftalat dan dietil glikol terhadap sifat biodegradabilitas PHA melalui pengukuran produksi dan laju produksi C02 yang dihasilkan selama pengujian biodegradasi pada media padat buatan. Selulosa digunakan sebagai pembanding relatif karena dianggap memiliki laju biodegradasi yang tinggi.
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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