Judul: Quality Improvement of Biodiesel from Rubber Seed Oil by Blending with Biodiesel from Jatropha curcas Oil
Abstrak: This research aimed to utilize rubber seeds oil and Jatropha curcas oil as raw material for biodiesel, to increase cetane number from rubber seed biodiesel, and to decrease viscosity from Jatropha curcas biodiesel. The proximate analysis of raw materials result showed that rubber seeds and Jatropha curcas seeds contained 37.96% and 41.66% of oil, respectively. Both types of seeds oil were separated using hydraulic hot press machine and the separation of rubber seeds gave 12.35% of yield and 13.12 % of free fatty acid, while the separation of Jatropha curcas seeds gave 18.34% of yield and 2.10% of free fatty acid. Esterification-transesterification process for biodiesel production was applied for rubber seeds oil and transesterification process to produce biodiesel from Jatropha curcas oil. Rubber seeds oil was esterified by using methanol and sulfuric acid 5% as catalyst for 1 hour and 300-500 rpm. Subsequently, rubber seeds methyl ester and Jatropha curcas oil were transesterified by using methanol and 1% sodium hydroxide as catalyst for 1 hour and 300-500 rpm. The result shows that cetane number from rubber seeds biodiesel and Jatropha curcas biodiesel sequentially were 46.35 and 53.7 and the viscosity was respectively 4.86 cSt and 6.16 cSt. Blending 20% rubber seed oil with 80% of Jatropha curcas oil and 20% rubber seed biodiesel with 80% of Jatropha curcas biodiesel increased cetane number of rubber seed biodiesel to 52 and 51.8, respectively, and decreased the viscosity of Jatropha curcas biodiesel to 5.92 cSt and 5.75 cSt, respectively.
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Judul: Sintesis dan Karakterisasi Biodiesel dari Minyak Biji Karet (Hevea brasiliensis) Melalui Proses Estrans (Esterifikasi- Transesterifikasi)
Abstrak: Biodiesel is alkyl ester produced from of vegetable, animal or fat oil derivate which could be used in diesel machine. One of the materials that can be used in making biodiesel is rubber seed oil. In order to influence the effective and efficient of biodiesel production, the process held in two steps esterificationtransesterification with the appropriate catalyst. The process had to be held in two step because of the high concentration of free fatty acid in rubber seed oil. The general purpose of this research was to add the utilization of rubber seed oil. The particular purposes of this research were to obtain the opted esterification-transesterification process from rubber seed oil and to know the characteristic of biodiesel produced from rubber seed oil esterificationtransesterification process and compare it with the obtained biodiesel standard. The result of proximate analysis of rubber seed showed that fat concentration in rubber seed was high enough about 38.65 % (dry basis) and the mean of rubber seed oil yield after extraction was 15.69 %. The characteristics of rubber seed oil after degumming were; cinematic viscosity at 40 oC was 23.31 cSt, the oil density at 25 oC was 0.896 g/ml and fatty acid value was 22.22 mg KOH/g of sample. Moreover, the oil could not be used directly as biodiesel because of three parameter values were higher than the standard. Therefore, the Esterification-Transesterification process must be carried out, so biodiesel that produced could fulfill the standard and could be used as fuel. Based on biodiesel production of rubber seed oil through Esterification- Transesterification could be known that the opted condition of esterification process was at A1B2C3 (HCl 1 %, reaction time 120 minutes, and mole ratio of methanol: oil = 20:1), fatty acid value was 0.32 mg KOH/g sample. The opted condition of transesterification was at A1B2 (reaction time 30 minutes and mole ratio of methanol:oil = 6:1), cinematic viscosity at 40 oC was 4.77 cSt, yield of biodiesel was about 74.51 %, and fatty acid value was 0.22 mg KOH/g of sample. Based on biodiesel characterization, the biodiesel quality produced in this research was appropriate with the standard of biodiesel for cinematic viscosity, density, fatty acid number, and flash point.
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Judul: Karakteristik Anatomi Skelet Kepala Buaya senyulong (Tomistoma schlegelii).
Abstrak: Buaya sepit atau senyulong (Tomistoma schlegelii) merupakan jenis buaya asli Indonesia yang berhabitat di sungai-sungai Sumatera, Kalimantan, dan juga pedalaman Sulawesi. Salah satu ciri khas buaya senyulong adalah bentuk moncong yang runcing dan sempit, namun hingga saat ini informasi mengenai struktur skelet kepala buaya senyulong sangat terbatas. Penelitian ini bertujuan untuk mempelajari karakteristik anatomi skelet kepala buaya senyulong yang dikatikan dengan fungsi dan perilakunya. Penelitian dilakukan secara eksploratif dengan melakukan pengamatan, pencatatan, dan pengambilan gambar dari skelet kepala buaya senyulong. Skelet kepala berukuran panjang 70 cm, lebar 29 cm, dan tingggi 17 cm dengan permukaan kasar pada os nasale, os frontale, os maxilla, os mandibula, os lacrimale, os jugale. Jumlah gigi pada buaya ini sebanyak 78 buah, terdiri dari 4 buah gigi premaxila, 16 buah gigi maxila, dan 19 buah gigi mandibula. Pada regio orbitalis ditemukan dua pasang fenestrae temporales yang berkembang baik. Fenestra supratemporale merupakan lubang oval yang membentang di sepanjang os parietale. Fenestra infratemporale berbentuk segitiga dan dibatasi oleh os squamosum, os postorbitale, os jugulare, dan os quadratum. Os mandibula hewan ini mempunyai symphysis mandibularis yang panjang yaitu garis yang melintang di corpus mandibulae. Secara fungsional ukuran symphysis mandibularis berkaitan dengan adaptasi hewan terhadap diet makan.
Keyword: kepala, moncong, Tomistoma schlegelii