Judul: Design of Rice Husk Biopellet Production Process with a Mixture of Coconut Shell and Sengon Wood Powder
Abstrak: CV Mekar Jaya memiliki limbah dari hasil samping proses penggilingan padi dan belum dimanfaatkan secara maksimal. Oleh sebab itu, dilakukan pemanfaatan limbah sekam padi menjadi biopelet dengan campuran serbuk kayu sengon dan tempurung kelapa. Tujuan dari penelitian ini merancang proses produksi biopelet, mendapatkan formulasi terbaik, menganalisis kualitas, menganalisis kelayakan finansial, dan menganalisis sensitivitas. Metode yang digunakan adalah metode kuantitatif. Penelitian dibagi menjadi beberapa fase, yaitu fase eksplorasi, fase pendefinisian masalah, fase ideasi, fase pengembangan prototipe, dan fase validasi. Formulasi yang digunakan dalam pembuatan biopelet terdiri dari 20% sekam : 80% arang tempurung kelapa, 20% serbuk kayu sengon : 80% arang sekam padi, 20% arang sekam padi : 80% serbuk kayu sengon, dan 20% arang sekam padi : 80% arang tempurung kelapa. Didapatkan formulasi terbaik dari keempat formulasi, yaitu formulasi 20% serbuk kayu sengon : 80% arang sekam. Hasil penelitian berhasil menghasilkan formulasi terbaik, proses produksi dan tata letak produksi yang efisien. Selain itu, hasil perhitungan menghasilkan HPP sebesar Rp 2.127.14/kg dan harga jual sebesar Rp 2.796.75/kg. Hasil analisis kelayakan finansial menunjukkan bahwa rencana pengembangan produk tersebut layak untuk dijalankan dengan nilai NPV sebesar Rp 1.016.463.004, IRR 40,84%, net B/C 1,170 dan PP 3 tahun 5 bulan. Hasil analisis sensitivitas menunjukkan bahwa pada kenaikan harga bahan baku 5% dan 15% menunjukkan hasil yang layak. Namun, dengan kenaikan harga bahan baku sebesar 30% proyek menjadi tidak layak. Hal ini menunjukkan bahwa kenaikan harga bahan baku sebesar 30% akan menyebabkan kerugian dan proyek tidak mencapai tujuan finansial yang diharapkan., CV Mekar Jaya has waste from the by-products of the rice milling process and has not been utilized optimally. Therefore, rice husk waste is used to become biopellets with a mixture of sengon wood powder and coconut shells. The purpose of this study is to design the biopellet production process, obtain the best formulation, analyze quality, analyze financial feasibility, and analyze sensitivity. The method used is a quantitative method. The research is divided into several phases, namely the exploration phase, the problem definition phase, the ideation phase, the prototype development phase, and the validation phase. The formulation used in the manufacture of biopellets consists of 20% husk: 80% coconut shell charcoal, 20% sengon wood powder: 80% rice husk charcoal, 20% rice husk charcoal: 80% sengon wood powder, and 20% rice husk charcoal: 80% coconut shell charcoal. The best formulation of the four formulations was obtained, namely the formulation of 20% sengon wood powder: 80% husk charcoal. The results of the research succeeded in producing the best formulation, efficient production process and production layout. In addition, the results of the calculation resulted in an HPP of Rp 2,127.14/kg and a selling price of Rp 2,796.75/kg. The results of the financial feasibility analysis show that the product development plan is feasible to be implemented with an NPV value of IDR 1,016,463,004, IRR of 40.84%, net B/C of 1,170 and PP of 3 years and 5 months. The results of the sensitivity analysis show that the increase in raw material prices by 5% and 15% shows decent results. However, with a 30% increase in raw material prices, the project
Keyword: biopelet, Formulasi, analisis kelayakan finansial, Analisis sensitivitas

Judul: Study of Biopellet Formulation Based on Albasia Wood Powder with a Mixture of Straw and Rice Husk Charcoal
Abstrak: Serbuk kayu albasia dan limbah padi merupakan salah satu sumber bahan bakar alternatif potensial berasal dari biomassa yang dapat dimanfaatkan menjadi biopelet sebagai solusi pemanfaatan limbah. Tujuan penelitian ini adalah menganalisis dan mengetahui karakteristik biopelet berbahan dasar serbuk kayu albasia dengan campuran jerami dan arang sekam serta mengetahui komposisi formulasi terbaik dari bahan dasar biopelet tersebut sebagai energi bahan bakar alternatif. Pembuatan biopelet menggunakan pelletizer tipe fixed dies dengan perbandingan formulasi bahan baku yaitu A0 (arang sekam 90% : perekat 10%), A1 (jerami padi 90% : perekat 10%), A2 (serbuk kayu albasia 90% : perekat 10%), A3 (serbuk kayu albasia 25% : jerami 25% : arang sekam 40% perekat 10%), A4 (serbuk kayu albasia 25% : jerami 40% : arang sekam 25% : perekat 10%), dan A5 (serbuk kayu albasia 40% : jerami 25% : arang sekam 25% : perekat 10%). Perlakuan terbaik biopelet diperoleh pada komposisi serbuk kayu albasia 90% dan perekat 10% berdasarkan nilai kadar air 10,62%, kadar abu 1,83%, dan kerapatan apparent 0,725 g/cm3 yang memenuhi standar SNI 8675:2018. Nilai kalor dari biopelet tersebut yaitu 17,16 MJ/kg., Albasia sawdust and rice waste are potential alternative fuel sources derived from biomass that can be used as biopellets as a solution for waste utilization. The purpose of this study was to analyze and determine the characteristics of biopellets made from albasia wood powder with a mixture of straw and husk charcoal and to determine the composition of the best formulation of these biopellets as alternative fuel energy. Making biopellets using a fixed dies type pelletizer with a ratio of raw material formulations, namely A0 (90% husk charcoal : 10% adhesive), A1 (90% rice straw : 10% adhesive), A2 (90% albasia wood powder : 10% adhesive), A3 (25% albasia wood powder : 25% straw : 40% husk charcoal : 10% adhesive), A4 (25% albasia wood powder : 40% straw : 25% husk charcoal : 10% adhesive), and A5 (40% albasia wood powder : 25% straw : 25% husk charcoal : 10% adhesive). The best treatment for biopellet was obtained at the composition of 90% albasia wood powder and 10% adhesive based on the value of water content of 10,62%, ash content of 1,83%, and apparent density of 0,725 g/cm3 which meet the standards of SNI 8675:2018. The calorific value of the biopellet is 17,16 MJ/kg.
Keyword: albasia sawdust, biopellet, fixed dies pelletizer, husk charcoal, rice straw

Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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