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: The influence analysis between fruit maturity and oil extraction method to quality of bintaro seed oil
Abstrak: Cerbera manghas L. (Bintaro) is a small evergreen coastal tree that could grow up to 12 m high. The color of leaves is shiny dark-green, ovoid in shape. Bintaro have a fairly high oil content of about 43-64% in seeds so it can be developed into biofuels. There are several factors that influence Bintaro seed oil quality, including the level of maturity and the used of extraction method. The research objective was to study the influence between fruits maturity level and oil extraction method on yield and quality of Bintaro seed oil. The fruits maturity level categorized into three types: immature fruit (dark-green), fruits that were ripe (bright red) and fruits that have been germinated. The extraction method of Bintaro seed oil consist of a mechanical pressing method using a hydraulic presser and hot hydraulic presser, and maceration extraction using n-hexane solvent. The greatest content of Bintaro seed was oil content which was 59,58 % for ripe Bintaro, 55,04 % for immature Bintaro and 45,56 % for germinate Bintaro. In order to achieve the efficiency of Bintaro seed extraction process, drying process was done earlier before the pressing stages. The oil obtained from the extraction process were characterized for each treatment. Based on the analysis, the best treatment for Bintaro seed oil production was the ripe fruit and extracted with maceration using n- hexane solvent method with a yield of 52.59 %, free fatty acid levels of 2.75 %, iodine value number was 60.31 I2/100g, peroxide value numbers was 5.85 mg O2 / g, saponification value number was 199.76 mg KOH / g, the viscosity value was 63 cP, the density value was 0.90 g/cm3, the % transmission was 87.43 % and the ash content was 0.40 %.
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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