Judul: Kajian Proses Pemurnian Minyak Nyamplung Sebagai Bahan Bakar Nabati.
Abstrak: Global energy crisis that occurred in the last decade gave the impact that was significant to increasing the fuel prices. Therefore, was required alternative energy development by using of renewable energy resources. One of the forest plants that have potential as raw materials for biofuels (BBN) is calophyllum. Calophyllum is potential to develop as non-food crops and land for growth does not compete with food crops. The use of the oil as a biofuel to form biodiesel, but the use of biodiesel from calophyllum still can not be applied operationally because the price is still higher than the price of diesel fuel. Therefore, the use of pure oil directly as biofuel becomes a more potent alternative to operationally. Technically crude calophyllum can be used as a biofuel substitute for diesel fuel, but the viscosity and free fatty acid levels still high and the presence of impurities compound remains a problem. This is necessary to study the purification and characterization of oils for this meet the required criteria and standards applicable. Oil refinery experienced two stages, namely the process of degumming and neutralization. Degumming is the sap or slime separation process that consists of phospolipid, proteins, carbohydrates, and water, while the neutralization was used to separate free fatty acids. Treatment of primary research consisted of two factors, namely phosphoric acid dose consisting of two levels: 0.2% and 0.3% (v/w) and concentration of NaOH solution which consists of three levels: 14°Be, 16°Be, and 18°Be.. The addition of caustic soda solution concentration had a significant impact on yield, acid number and content of free fatty acids, saponification numbers, peroxide number, ash content, and viscosity. While dosage phosphoric acid tends to decrease the value of ash content and viscosity, but did not affect any other parameters (yield, acid number and levels of free fatty acids, saponification numbers, and peroxide numbers).
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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: Grup dan Homomorfisma Grup pada Rubik Revenge
Abstrak: Rubik cube is a kind of puzzle game. A player must arrange rubik sides, which have been disordered, back to the position where every side has the same colour. This paper does not focus on the settlement solution, but instead on proving the existence of a group homomorphism between rubik movement group and S96 symmetric permutation group in rubik revenge. Firstly, it has been proved that rubik movement set is a group. Then, it also has been proved that the M set, which contains numeric labels of 1 until 96 in cubinos sides, is S96 symmetric permutation group.
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