Judul: Study Production Process of Biodiesel from Alexandrian Laurel Seed Oil (Calophyllum inophyllum L.).
Abstrak: National fossil fuel consumption is increasing. In 2004, solar consumption rise to 26,9 billion liters, at 2010 is predicted to rise to 34,71 billion liters. The consumption of fossil inbalance with its production, this performance need to overcome by looking for an alternative energy resources. Palm oil, jatropha and calophyllum were some of agriculture abundant available in Indonesia. The jatropha used was constrained by a low oil production, average oil production is 1.892 liters/ha/year. Whereas palm oil is 5.950 liters/ha/year, however it compete with food needs and other oleochemical product. The use of calophyllum give an advantage as its production of 100 kg (220 lb) nuts/tree/year or 4.585 kg oil/ha/year. Although the oil has a high acid value and takes longer time that is 7 or 8 years before fruit production. The research was done by combining the process that is esterification, transesterification and netralization to produce oil to meet the SNI standard (number 04-7182-2006). The purpose of this research was to determine the molar ratio of methanol in esterification, and esterification time to obtain oil with low acid value. The esterification conditions than combine with transesterification and netralization in order to produce biodiesel that meet the standard requirement. The best oil produced from esterification was obtained by applying molar ratio methanol of 20:1 in 60 minute, the acid value of oil was 2,97 mg KOH/g feed. The best process combination to produce biodiesel obtained by esterificationnetralization- transesterification (E1NT) applying molar ratio methanol of 20:1 in 60 minute. Its gave acid value 0,71 mg KOH/g feed, kinematic viskosity 2,59 cSt, density 0,89 g/ml, water content 0,05% and yield 47,76%.
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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: Closed Knight’s Tour pada Papan Catur Berbentuk Persegi Panjang dengan Ukuran Maksimal 8 × 8
Abstrak: Closed Knight’s Tour merupakan langkah kuda yang mengunjungi setiap kotak pada papan catur tepat satu kali dengan langkah kuda berawal dan berakhir pada kotak yang sama. Graf yang terbentuk dari closed knight’s tour dinotasikan sebagai graf G(m,n), dengan m adalah banyaknya baris dan n adalah banyaknya kolom. Graf tersebut memuat Hamiltonian cycle. Sebuah graf terhubung G adalah graf bipartite jika dan hanya jika graf tersebut tidak memiliki cycle dengan panjang ganjil. Papan catur yang memenuhi syarat cukup untuk memiliki closed knight’s tour adalah papan catur berukuran 5 × 6, 5 × 8, 6 × 6, 6 × 7, 6 × 8, 7 × 8, dan 8 × 8.
Keyword: bipartite, closed knight’s tour, hamiltonian cycle, knight’s tour, teori graf