Judul: Evaluation of Technology Process of Calophyllum Oil Application as Biofuel on
Abstrak: Sebagai biofuel, penggunaan minyak nyamplung (Calophyllum inophyllum L.) belum dapat diterapkan secara operasional karena harganya yang tinggi dan karakteristiknya belum sesuai dengan standar BBM. Masalah ini dapat diatasi dan diminimalisir melalui penggunaan teknologi proses yang baik dan sesuai. Penelitian ini bertujuan untuk mengevaluasi teknologi proses aplikasi minyak nyamplung sebagai biofuel dan memilih teknologi proses terbaik. Teknologi proses terbaik ditentukan menggunakan metode perbandingan kelebihan dan kekurangan. Hasil evaluasi menunjukkan produksi minyak nyamplung diawali dengan persiapan bahan baku menggunakan teknologi dan proses ekstraksi yang digunakan, yaitu teknologi ekstraksi menggunakan pelarut biner (campuran n-heksan dan metanol). Tahapan proses terpilih untuk memproduksi pure plant oil (PPO) adalah persiapan bahan baku, ekstraksi minyak dengan pelarut biner serta pemurnian dengan degumming dan netralisasi. Tahapan proses terpilih untuk memproduksi biodiesel adalah persiapan bahan baku, ekstraksi minyak dengan pelarut biner, degumming, esterifikasi, transesterifikasi, dan purifikasi kering. Proses terpilih untuk memproduksi biogasoline adalah hydrocracking. Proses terpilih lebih efisien, efektif, menghasilkan rendemen dan kualitas produk yang tinggi serta kompatibel diterapkan dalam skala industri. Produksi minyak nyamplung sebanyak 1180 kg/hari dan resin sebanyak 360 kg/hari dengan harga pokok produksi senilai Rp 34 714.23/kg. Rasio nilai tambah minyak sebagai bahan baku biofuel sebesar 52.11% dan tingkat keuntungan sebesar 45.62%., As a biofuel, the use of Calophyllum oil hasn’t been able to be applied operationally because of its high price and its unaccordance characteristics with fuel oil standard. This problem can be overcome and minimized by using good and appropriate processing technology. This research aims to evaluate the processing technology of Calophyllum oil application as biofuel on industrial scale, and to select the best processing technology. The best processing technology was determined by using the advantages and disadvantages comparison method. The evaluation results showed that the production of Calophyllum oil was started by preparation of raw materials using technology and the oil extraction using binary solvent of n-hexane and methanol mixture. The selected processing steps to produce pure plant oil (PPO) were the preparation of raw materials, the oil extraction with binary solvent, and the oil purification by degumming and neutralization. The selected processing stages to produce biodiesel were raw material preparation, oil extraction with binary solvent, degumming, esterification, transesterification, and dry purification. The selected process to produce biogasoline was hydrocracking. The selected process was more efficient, effective, produced high yield and product quality, and were compatible to be applied on industrial scale. The production of Calophyllum oil was at 1180 kg/day and resin at 360 kg/day with the price of production cost of IDR 34 714.23/kg. The added value of oil as raw material for biofuel was 52.11% and the profit was at 45.62%.
Keyword: biofuel, technology evaluation, oil, added value, Calophyllum

Judul: Temperature and Time Optimization in Purification of Calophyllum Oil
Abstrak: Kebutuhan bahan bakar minyak terus meningkat mengakibatkan ketersediaannya terbatas. Salah satu upaya terbaik yaitu mengembangkan energi alternatif. Tanaman nyamplung berpotensi tinggi sebagai sumber untuk bahan bakar nabati karena biji dari buah nyamplung menghasilkan minyak non pangan dengan rendemen tinggi. Untuk memenuhi standar mutu bahan bakar nabati, minyak nyamplung kasar perlu dimurnikan terlebih dahulu. Penelitian ini bertujuan mengoptimasi suhu (70–90 oC) dan waktu (10–30 menit) pada proses pemurnian minyak nyamplung kasar hasil proses ekstraksi dengan pelarut biner agar mendapatkan karakteristik minyak yang sesuai standar mutu minyak murni sebagai bahan bakar nabati. Penelitian ini menggunakan rancangan percobaan central composite design dengan variabel bebas suhu dan waktu, sedangkan optimasi dilakukan menggunakan response surface method. Model terbaik hasil optimasi rendemen minyak adalah model kuadratik. Rendemen minyak nyamplung murni optimum sebesar 44,62% yang diperoleh pada suhu 81,44 oC dan waktu 19,93 menit. Maksimasi rendemen minyak dengan batasan bilangan asam menghasilkan rendemen minyak dan bilangan asam optimum berturut-turut sebesar 44,44% dan 2,43 mg-KOH.g-1 diperoleh pada suhu 83,38 oC dan waktu 19,70 menit. Validasi terhadap kondisi proses optimum menghasilkan rendemen minyak 46,40% dengan mutu minyak sebagai berikut: densitas 0,906 g.cm-3, viskositas 19,67 cSt, bilangan asam 2,39 mg-KOH.g-1, kadar air 0,042%, dan kadar abu 0,027%. The increasing demand has caused a limited fuel oil availability. One of the best efforts is to develop alternative energy. The Calophyllum plant has high potential as a source for biofuel because the seeds of the Calophyllum fruit produce non food oil with high yields. To fulfill the quality standards of biofuels, crude Calophyllum oil needs to be purified first. The purpose of this study was to optimize the temperature (70–90 oC) and time (10–30 min) in the refining process of crude Calophyllum oil extracted using binary solvent to obtain the oil with characteristics according to pure oil standards as biofuel. This study used an experimental design of the central composite design with variables of temperature and time, while optimization was carried out using the response surface method. The best model for the optimization of oil yield was the quadratic model. The optimum oil yield was 44.62% which was obtained at a temperature of 81.44 oC and a time of 19.93 min. The optimization of the oil yield with the acid value as constraint resulted respectively in the optimum oil yield and acid value of 44.44% and 2.43 mg- KOH.g1, which were obtained at a temperature of 83.38 oC and a time of 19.70 min. Validation of the optimum process conditions resulted in an oil yield of 46.40% with oil quality such as: density 0.906 g.cm-3, viscosity 19.67 cSt, acid value 2.39 mg-KOH.g-1, water content 0.042%, and 0.027% ash content.
Keyword: Calophyllum, oil, optimization, refining, response surface method

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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