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: Transformation of jatropha seeds (Jatropha curcas L.)  into biodiesel by in situ transesterification
Abstrak: Biodiesel is defined as mono-alkyl esters from transesterification reaction of triglycerides with alkyl alcohol. In situ transesterification is a method to produce biodiesel from oil sources of material by eliminating process steps of oil extraction and refining. The purpose of this research is to study the transformation process of Jatropha seeds into biodiesel by in situ transesterification on the 10 liters scale by studying the influence of reaction time, stirring speed and ratio methanol/hexane/material on the yield and quality of biodiesel. In situ transesterification of Jatropha seeds was carried out under the following process condition: the moisture content of Jatropha seeds were less than 2%, the particles size were ± 20 mesh and KOH concentration was 0.075 mol/L methanol. Operating condition of in situ transesterification was varied at 4 and 6 hours reaction time, 200 and 600 rpm stirring speed and ratio methanol/hexane/material (v/v/w) were 3:3:1, 4:2:1 and 5:1:1. Analysis of variance showed that reaction time, stirring speed and ratio methanol/hexane/material did not significantly affected the yield, acid value, saponification value, ester value, viscosity and ash content of biodiesel. The biodiesel yield was produced between 82.54-87.57%. The best biodiesel yield on all of treatments was 87.57% with condition treatment were reaction time of 6 hours, stirring speed 600 rpm and ratio methanol/hexane/material (v/v/w) of 4:2:1. Acid value, saponification value and ester value of biodiesel were 0.20-0.26 mg KOH/g, 185.49-194.30 mg KOH/g and 185.29-194.10 mg KOH/g respectively. Viscosity of biodiesel was 3.49-6.36 cSt. The ash content of biodiesel was 0%, but the condition treatment, were reaction time of 4 hours, stirring speed of 600 rpm and ratio methanol/hexane/material (v/v/w) of 5:1:1, had ash content of 0.007%. Jatropha cakes had total volatile matter content 1.80-3.64% and extracted material content 3.94-11.42%.
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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