Judul: Modifikasi Sistem Pelontar pada Unit Penanam Stek Singkong
Abstrak: Unit penanam stek singkong yang dirancang oleh Kurniawan (2017) masih memiliki masalah pada keandalan bahan silinder dan penyesuaian diameter stek. Tujuan penelitian ini memodifikasi sistem pelontar unit penanam stek singkong hasil penelitian Kurniawan (2017) dan membandingkan hasil pengujian unit setelah modifikasi. Modifikasi yang dilakukan antara lain mengubah mekanisme belt sebagai komponen pengarah menjadi single roller, mengganti bahan silinder, menerapkan mekanisme pegas sebagai komponen pendukung dalam menyesuaikan diameter stek. Bahan silinder yang digunakan polyurethane berdiameter 10 cm, jarak antara dua silinder 2.60 cm. Digunakan perbandingan pulley 1:1.75 untuk mendapatkan kecepatan putar silinder 2450 rpm dari kecepatan putar sumber 1400 rpm. Pegas berukuran 40 mm dengan rata-rata diameter 40 mm dan jumlah lilitan tiga. Mekanisme pegas didukung pillow block tipe take up. Hasil pengujian fungsional dari 10 sampel menunjukkan hasil yang cukup optimal dengan 60% stek tertanam tegak, 20% stek miring, dan 20% stek rebah. Hasil pengujian daya tumbuh didapat 100% stek tumbuh sehingga dapat dikatakan modifikasi desain tidak menimbulkan kerusakan yang mempengaruhi daya tumbuh stek singkong.
Keyword: modifikasi, pegas, pelontar, polyurethane, stek

Judul: Desain Fungsional Unit Penanam Stek Singkong
Abstrak: Singkong merupakan tanaman dan sumber pangan paling penting nomor tiga di dunia. Di Indonesia singkong dijadikan makanan pokok setelah beras dan jagung. Budidaya singkong di Indonesia umumnya masih dilakukan dengan tenaga kerja manusia, terutama pada kegiatan penanaman. Dalam rangka penerapan mekanisasi pertanian pada budidaya singkong, maka pada penelitian ini dilakukan perancangan fungsional unit penanam stek singkong. Mekanisme yang digunakan pada penanam singkong ini adalah dengan menembakkan stek singkong ke tanah. Hasil pengujian menunjukan rata-rata kedalaman tanam stek singkong yang ditembakkan adalah 6.6 cm, dimana 83.33% stek tertanam tegak (≥70°) dan 16.67% tertanam miring (<70°). Daya tumbuh stek singkong yang ditanam dengan desain ini adalah 100%.
Keyword: desain fungsional, penanaman, stek singkong

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