Judul: Study of bintaro (Cerbera Manghas L) oil purification process for biofuel
Abstrak: Bintaro plant is one of the vegetable oils producers which potential to be developed. Generally, crude bintaro oil from extraction process still contain impurities, which consists of three groups, which are non-soluble in oil (fat insolube and dispersed in oil), impurities in the form of colloidal suspension in oil (phospholipid, carbohydrate), impurities dissolved in oil (fat solube compound) such as free fatty acids, sterols and hydro carbon.The purification process is to remove oil impurities and improve is quality. It therefor is necessary to study the purification and characterization of oils for meet the required criteria and application standart. Oil refinery experienced three stages, which are the process of degumming, neutralization and bleaching. Degumming is the slime separation process that consist of phospolipid, proteins, carbohydrates, and waters, while the neutralization was used to separate free fatty acids and bleaching process to remove unwanted colors. The factor used in this study are phosphoric acid dose consisting of three levels: 0.2%, 0.3% and 0.5% (v/b) and consentration of NaOH solution which consist of three levels: 0.1 N, 0.3N, and 0.5N. The addition of caustic soda solution concentration had a significant impact on yield, acid number and content of free fatty acids, peroxide number, viscosity, and percent transmission. While dosage phosphoric acid had a significant impact on changes in the value of the yield, ash content, viscosity, and percent transmission. While other parameters such as saponification number, iodine number, and density of oil is not influenced by the concentration of caustic soda and phosphoric acid solution dose.
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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