Judul: Peningkatan Produksi Listrik Sel Bahan Bakar Mikroba dengan Penghilangan rpoS dari Escherichia coli
Abstrak: Sel bahan bakar mikroba (Microbial Fuel Cell disingkat MFC) merupakan salah satu alternatif produksi listrik yang memanfaatkan mikroba untuk mengubah energi kimia dalam biomassa menjadi listrik. Nikotinamida Adenosin Dinukleotida Hidrogen (NADH), produk metabolisme karbon pusat dan asam nukleat, merupakan komponen utama dalam pembentukan sistem MFC. Peningkatan NADH dilakukan dengan menghilangkan rpoS dan menigkatkan putaran pada kultivasi Escherichia coli untuk merekayasa metabolisme. Penelitian ini bertujuan untuk mendapatkan pengaruh penghilangan rpoS pada E. coli dan putaran kultur bergoyang terhadap peningkatan listrik MFC. E.coli dikutivasi dalam kondisi aerobik pada media Luria Bertani yang diperkaya glukosa. Pengukuran tegangan dilakukan di akhir fase stasioner, yakni kultivasi jam ke-24. Tegangan listrik yang dihasilkan E. coli yakni 7.25 mV. Sementara, produksi listrik oleh E. coli yang kehilangan gen rpoS meningkat signifikan, 1.5 kali lipat dari sel induk, yakni 10.25 mV. Peningkatan produksi listrik lebih jauh, yakni 2.25 kali lipat dicapai dengan peningkatan putaran E. coli ΔrpoS, hingga tegangan mencapai 23 mV.
Keyword: Escherichia coli, gen rpoS, kultivasi aerobik, MFC, NADH, oksigenasi

Judul: Peningkatan Energi Listrik Sel Bahan Bakar Mikroba melalui Perubahan Status Redoks pada Escherichia Coli
Abstrak: Kebutuhan energi di bidang industri sangat tinggi. Salah satu teknologi sumber energi alternatif yang dapat diperbaharui yaitu sel bahan bakar mikroba (microbial fuel cell / disingkat MFC). Format dehidogenase (FDH) yang telah ditransformasikan pada E. coli mampu meregenerasi NAD+ menjadi NADH dengan mendekomposisi format menjadi CO2. Tujuan dari penelitian ini adalah mendapatkan pengaruh penyisipan jalur FDH dan penambahan format pada kultur E. coli terhadap peningkatan produksi energi listrik dalam rangkaian MFC. Perubahan tegangan listrik yang dihasilkan dapat dikonfirmasi melalui analisis bobot sel kering, konsumsi glukosa, format sisa, dan akumulasi asetat serta piruvat. Sel E. coli ditumbuhkan dalam kondisi aerob melalui penambahan format dengan konsentrasi 4 g/l pada kultur bergoyang 200 rpm selama 24 jam. Penyisipan jalur FDH dan penambahan format pada kultur E. coli terbukti dapat meningkatkan tegangan listrik pada rangkaian MFC dari 7.15 menjadi 20.35 mV. Sementara itu, penambahan format pada induk sel E. coli hanya meningkatkan tegangan listrik dari 7.15 menjadi 13.2 mV.
Keyword: Escherichia coli, sel bahan bakar, tegangan listrik, format dehidrogenase, NADH

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