Judul: Optimization of Oxygen Flow Valve Hole in Small Industrial Scale  Husk Furnaces
Abstrak: Penggunaan bahan bakar berbasis fosil seperti minyak bumi dan gas bumi yang semakin tinggi menyebabkan adanya ketidakseimbangan kebutuhan energi dengan ketersediaan energi tersebut. Oleh karena itu dilakukan pemanfaatan biomassa sekam padi sebagai energi alternatif yang diaplikasikan pada kompor biomassa berupa tungku sekam. Tujuan penelitian adalah untuk mengoptimasi efisiensi tungku sekam skala industri kecil dengan menvariasikan lubang katup aliran oksigen dan massa air yang dipanaskan. Pengujian pada tungku sekam dilakukan dengan metode Water Boiling Test (WBT) dengan parameter uji: waktu pembakaran, FCR, daya masuk, daya keluar, daya yang hilang, energi radiasi, dan konduktivitas termal bagian wajan dan cerobong tungku sekam. Pengujian dilakukan terhadap 4 variasi lubang katup aliran oksigen (horizontal: 18 x 36 cm2 dan 27 x 36 cm2, vertikal: 27 x 24 cm2 dan 27 x 12 cm2) dan 3 variasi massa air yang dipanaskan (6 kg, 12 kg, 18 kg). Diperoleh efisiensi tungku sekam paling tinggi pada pemanasan 18 kg air, dan berdasarkan tiap parameter uji, kinerja tungku sekam paling optimum pada lubang katup horizontal 27 x 36 cm2 dengan rata-rata efisiensi 17,32%., The increasing use of fossil-based fuels such as oil and natural gas causes an imbalance between energy demand and the availability of that energy. Therefore, the use of rice husk biomass as an alternative energy is applied to a biomass stove in the form of a husk stove. The aim of this research is to optimize the efficiency of a small industrial scale husk furnace by varying the oxygen flow valve holes and the mass of the heated water. The test on the husk furnace was carried out using the Water Boiling Test (WBT) method with test parameters: combustion time, FCR, input power, output power, power loss, radiant energy, and thermal conductivity of the pan and chimney of the husk furnace. Tests were carried out on 4 variations of the oxygen flow valve holes (horizontal: 18 x 36 cm2 and 27 x 36 cm2, vertical: 27 x 24 cm2 and 27 x 12 cm2) and 3 variations in the mass of heated water (6 kg, 12 kg, 18 kg). The highest efficiency of the husk furnace was obtained at heating 18 kg of water, and based on each test parameter, the performance of the husk furnace was most optimum at the horizontal valve hole 27 x 36 cm2 with an average efficiency of 17.32%.
Keyword: efficiency, husk furnace, optimization, oxygen flow valve hole, rice husk, WBT

Judul: Perluasan Lubang Katup Aliran Oksigen Pada Tungku Sekam Skala Industri Kecil
Abstrak: Indonesia memiliki total luas panen padi yang cukup luas serta menghasilkan jumlah padi yang melimpah. Selain padi yang dihasilkan, terdapat produk sampingan yang dihasilkan dan sering dianggap sebagai limbah yaitu sekam padi. Oleh karena itu, limbah sekam padi perlu dimanfaatkan lebih optimal agar lebih bermanfaat bagi masyarakat. Penelitian ini bertujuan mengoptimalkan efisiensi tungku sekam dengan memvariasikan ukuran lubang katup aliran oksigen dan massa air yang dipanaskan. Pengujian dilakukan terhadap empat variasi ukuran lubang katup aliran oksigen yaitu, 36x27 cm2, 36x34 cm2, 43x34 cm2, dan 50x34 cm2 serta dua variasi massa air (6 dan 18 kg). Penelitian dilakukan dengan memanaskan air menggunakan metode Water Boiling Test dengan parameter uji: waktu pemanasan, Fuel Consumption Rate, energi masuk, energi keluar, efisiensi kalor, laju perpindahan kalor, konduktivitas termal wajan, konduktivitas termal cerobong tungku sekam, serta rendemen abu dan arang. Efisiensi terbesar bernilai 54,99% yang diraih oleh lubang katup berukuran 43x34 cm2 pada pemanasan air 18 kg., Indonesia has a relatively large total rice harvest area and produces abundant rice. In addition to the rice produced, there are by-products produced and often considered waste, namely rice husks. Therefore, rice husk waste must be utilized optimally to be more beneficial for the community. This research aims to optimize the efficiency of chaff furnaces by varying the size of oxygen flow valve holes and the mass of heated water. Tests were carried out on four variations in the size of oxygen flow valve holes, namely, 36x27 cm2, 36x34 cm2, 43x34 cm2, and 50x34 cm2, as well as two variations in water mass (6 and 18 kg). This study was conducted by heating water using the Water Boiling Test method with test parameters: heating time, Fuel Consumption Rate, inlet energy, outgoing energy, heat efficiency, heat transfer rate, the thermal conductivity of the pan and the husk furnace chimney, also ash and charcoal yield. The most excellent efficiency is 54.99%, achieved by a valve hole measuring 43x34 cm2 at 18 kg water heating.
Keyword: Efisiensi, Lubang Katup Aliran Oksigen, Perluasan, Sekam Padi, Tungku Sekam, Efficiency, Expansion, Husk Furnace, Oxygen Flow Valve Holes, Rice Husk

Judul: Posisi Filogenetik Kura-Kura Carettochelys Insculpta  (Reptillia: Testudinata)
Abstrak: Carettochelys insculpta is an endemic freshwater turtle of southern Papua and northern Australia. Phylogenetic position of this turtle is remain unresolved until now. Most of the research conducted show close relationships of C. insculpta and members of Trionychidae family. However, some of the research show distance between C. insculpta and members of Trionychidae family. This research is conducted to analyze phylogenetic relationship between C. insculpta and other members of Testudinata using 12S rRNA, 16S rRNA, and both gene as markers. DNA samples were obtained from three different organisms of C. insculpta. Two species used as outgroups were Alligator mississippiensis and Iguana iguana. Phylogenetic analysis was carried out using Neighbor-Joining method with Felsenstein 1981 (F81) modeltest. A polytomy tree of Testudinata was produced by using 12S rRNA gene. However, analysis using 16S rRNA and both genes as markers confirmed that C. insculpta was located between the Chelonidae and the Trionychidae family.
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