Judul: Biosorpsi Cd(II) dan Pb (II) menggunakan kulit jeruk siam (Citrus reticulata)
Abstrak: Logam- logam yang beracun sering dihasilkan dari beberapa proses industri dan menimbulkan permasalahan pada lingkungan. Logam berat merupakan pencemar yang banyak terdapat di tanah dan perairan. Salah satu metode yang biasa digunakan untuk mengatasi logam berat adalah fisika-kimia. Akan tetapi, metode fisika-kimia sangat mahal dan tidak efektif. Oleh karena itu, biosorpsi menjadi salah satu alternatif untuk mengatasi pencemaran logam berat. Pada penelitian ini, biosorpsi kadmium dan timbal dipelajari dengan menggukan kulit jeruk siam (Citrus reticulata). Parameter yang dipelajari adalah waktu kontak, konsentrasi larutan logam, suhu, pH larutan, bobot biosorben, dan ukuran biosorben.
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Judul: Pemanfaatan Limbah Kulit Batang Karet sebagai Biosorben Ion Kromium(VI) dan Timbel(II)
Abstrak: Rubber stem bark is a fair amount waste in South Sumatera which is potential to be utilized. This study utilized the rubber stem bark as chromium and lead ion heavy metal biosorbent in the water. The method used was batch method which observation parameters included the influence of biosorbent particle size, pH, and contact time. The optimum condition was determined by Duncan test. Results showed that the optimum condition of Cr(VI) biosorption occured at 100 mesh particle size, pH 2, and 1 hour contact time, whereas the optimum condition of Pb(II) biosorption occur at 100 mesh particle size, pH 7, and 1 hour contact time. Biosorption equilibrium of chromium and lead followed the Freundlich isotherm model (linearity = 98.80% and 93.92%). Maximum adsorption capacity based on the Freundlich equation was 0.55 mg Cr(VI) and 0.98 mg Pb(II) for one gram of adsorbent.
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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