Judul: Produksi Biolistrik Limbah Cair Pemindangan dengan Sistem Salt Bridge Microbial Fuel Cell Berbahan Natrium Alginat
Abstrak: Microbial fuel cell (MFC) merupakan suatu teknologi alternatif penghasil energi listrik dari limbah cair. Microbial fuel cell dua bejana terdiri dari bejana anoda dan katoda yang dihubungkan oleh membran penukar proton maupun jembatan garam. Na-alginat merupakan polimer alami yang dapat dijadikan media jembatan garam. Penelitian ini bertujuan menentukan produksi biolistrik dan penurunan beban polusi dari limbah cair pemindangan dengan sistem salt-bridge microbial fuel cell berbahan Na-alginat. Konsentrasi Na-alginat yang digunakan yaitu 10%, 15%, dan 20%. Nilai elektrisitas tertinggi diperoleh pada perlakuan konsentrasi Na-alginat 20% yaitu nilai tegangan listrik sebesar 1,53 V, arus listrik sebesar 3,96 mA, dan daya listrik sebesar 6,03 mW. MFC jembatan garam Na alginat mampu menurunkan parameter biological oxygen demand (BOD) dan total ammonia nitrogen (TAN) sebesar 73% dan 76%. Perbedaan konsentrasi Na-alginat mempengaruhi kinerja MFC. Perlakuan terbaik terdapat pada konsentrasi Na-alginat 20%., Microbial fuel cell is an alternative technology for producing electrical energy from wastewater. Dual chamber MFCs consists of anode and cathode chambers connected with a proton exchange membrane or salt bridge. Sodium alginate is a natural polymer that can be used as salt bridge medium. This study was aimed to determine the bioelectric production and reduce the pollution load from the effluent using salt-bridge microbial fuel cell system made from Na-alginate. The sodium alginate concentrations used were 10%, 15%, and 20%. The highest value of electricity was obtained in the treatment of 20% sodium alginate concentration, the electric voltage was 1,53 V, the electric current was 3,96 mA, and the electric power was 6,03 mW. Sodium alginate salt bridge MFCs were able to reduce BOD and TAN parameters by 73% and 76%, respectively. Differences in Na-alginate concentrations affect MFC performance. The best treatment was at a concentration of 20% Na-alginate.
Keyword: elektrisitas, jembatan garam Na-alginat, limbah cair perikanan, microbial fuel cell

Judul: Kinerja Membran Komposit Kitosan-Sodium Alginat pada Sistem Microbial Fuel Cell dalam Menghasilkan Biolistrik dari Limbah Pemindangan Ikan.
Abstrak: Microbial Fuel Cell (MFC) merupakan sumber energi alternatif sebagai penghasil energi listrik dan dapat berasal dari limbah cair perikanan. Membran yang umum digunakan pada MFC yaitu membran nafion tetapi harganya mahal dan harus impor. Alternatif lain yaitu membuat membran dari kitosan dan sodium alginat. Penelitian ini bertujuan menentukan kinerja MFC dalam menghasilkan elektrisitas menggunakan membran kitosan-sodium alginat. Penelitian ini dilakukan dengan empat tahapan yaitu melakukan karakterisasi limbah cair perikanan yang meliputi BOD, COD, pH dan TAN, membuat dan mengkarakterisasi membran komposit dengan perlakuan komposisi alginat dengan kitosan 1:1, 2:1, dan 3:1 (v/v), membuat desain MFC serta mengukur kinerja listrik MFC. Membran kitosan-sodium alginat 2:1 (v/v) menghasilkan nilai elektrisitas tertinggi yaitu tegangan sebesar 0,960±0,077 V, kuat arus sebesar 3,909±2,354 mA dan daya listrik sebesar 3,717±2,176 mW.
Keyword: energi listrik, membran kitosan-sodium alginat, microbial fuel cell

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