Judul: Analisa ekonomi pembangkit gas bio pada suatu model perencanaan pemanfaatan energi gas bio dalam suatu usaha tani
Abstrak: Teknologi gas bio merupakan teknologi yang memanfaatkan limbah organik melalui proses fermentasi anaerobik untuk menghasilkan gas bio yang memiliki nilai kalor yang cukup tinggi, sehingga dapat dimanfaatkan sebagai bahan bakar. Teknologi ini cukup potensial untuk dikembangkan di pedesaan karena teknologinya relatif sederhana, kotoran ternak mudah diperoleh, menghasilkan bahan bakar yang bersih serta pupuk organik yang melimpah dan tinggi mutunya. Pengembangan teknologi gas bio diharapkan dapat memberikan manfaat, antara lain seperti usaha pencegahan erosi dan kerusakan hutan, sanitasi lingkungan, pemanfaatan kembali limbah dan pengusahaan energi yang terbaharui. Selain itu juga diharapkan dapat meningkatkan standar hidup dan kesempatan kerja masyarakat. Tujuan dari penelitian ini, yaitu melakukan perhitungan biaya pem- buatan terhadap beberapa ukuran konstruksi pembangkit gas bio tipe BIP Banpres dan melakukan analisa ekonomi terhadap daya saing bahan bakar gas bio dengan bahan bakar lain serta analisa kelayakan model pembangkit gas bio yang direncanakan. Model konstruksi pembangkit gas bio yang dipilih adalah model BIP- Banpres yang merupakan modifikasi dari pembangkit gas bio model Cina. Dari hasil penelitian yang telah dilakukan sebelumnya, dinyatakan bahwa pem- bangkit gas bio model Cina lebih menguntungkan daripada model India (Thongkaimook, 1980 dan Usman S., 1992). Pada penelitian ini, gas bio yang dihasilkan dimanfaatkan untuk memenuhi kebutuhan rumah tangga, kegiatan pra panen dan kegiatan pasca panen. Untuk memenuhi kebutuhan rumah tangga, gas bio yang dihasilkan dipergunakan untuk menggantikan bahan bakar minyak tanah. Dari hasil analisa, biaya energi efektif bahan bakar gas bio masih lebih mahal daripada biaya energi efektif bahan bakar minyak tanah. Pada pembangkit gas bio ukuran 82.54 m³, biaya energi gas bio sebesar Rp 0.1029/kkal sedangkan biaya energi efektif bahan bakar minyak tanah sebesar Rp 0.0679/kkal. ...
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Judul: Analisis finansial terhadap beberapa model pembangkit biogas untuk pedesaan
Abstrak: Biogas adalah campuran dari gas Metana (CH4), sedikit. H2S, N2, H2, CO2 serta senyawa hidrokarbon lain yang dihasilkan melalui proses fermentasi anaerob terhadap bahan-bahan organik seperti kotoran ternak dan manusia, limbah pertanian dan industri dengan kadar bahan organik lebih dari 2 persen. 3'500 - Biogas mempunyai nilai kalor antara 6 500 kkal/m³ (kadar CH4 antara 40 - 60 persen). Biogas dapat digunakan untuk memasak, penerangan serta untuk menggerakkan mesin. Teknologi biogas sangat potensial untuk dikembangkan di pedesaan karena teknologinya relatif sederhana, kotoran ternak mudah diperoleh, menghasilkan bahan bakar yang murah dan bersih serta pupuk organik yang tinggi mutunya. Pengembangan teknologi biogas juga diharapkan dapat mem- berikan manfaat lain seperti usaha pencegahan erosi dan kerusakan hutan, sanitasi lingkungan, pemanfaatan kembali limbah serta pengusahaan energi yang terbarui. ...
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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