Judul: Formulation of Biodiesel B50 Additive Based on Glycerol Ester and Storage Stability Test
Abstrak: Fatty Acid Methyl Ester (FAME) merupakan biodiesel yang saat ini digunakan di Indonesia. Pencampuran FAME dan diesel oil masih terdapat kendala: FAME terpisah dengan diesel oil pada suhu rendah. Penurunan kualitas biodiesel disebabkan perubahan sifat fisiko kimia selama penyimpanan, karena adanya oksigen terlarut yang berpotensi merusak mesin. Permasalahan tersebut dapat diatasi dengan aditif gliserol ester (GE). Penelitian ini terdiri atas dua tahap. Pertama, sintesis GE dengan mereaksikan gliserol 99,9% dan asam oleat (1:1 mol/mol) menggunakan katalis PTSA dialiri gas nitrogen 100 cc/menit. Reaksi esterfikasi dilakukan pada suhu 140, 160, 180, dan 240oC pengadukan 400 rpm selama 180 menit. Analisis fisiko kimia GE meliputi: rendemen, angka asam, densitas, viskositas kinematis, dan FTIR. Tahap kedua adalah GE terbaik digunakan sebagai aditif pada biodiesel B50. Jenis aditif divariasikan yaitu GE dan aditif komersial dietil eter (DEE) konsentrasi 1000, 2000, dan 3000 ppm, suhu penyimpanan 25, 12, dan 42oC. Pengujian stabilitas penyimpanan selama 3 bulan, meliputi: angka asam, viskositas, laju korosifitas, dan kadar air. Sintesis gliserol ester suhu terbaik berdasarkan metode Analytical Hierarchy Process (AHP) adalah suhu 160oC dengan atribut rendemen, pH, angka asam, viskositas kinematis, densitas. Rendemen pada suhu 160oC sebesar 95,66%, pH 7, nilai angka asam 11,28 mg KOH/g sampel, viskositas kinematis 75,76 cst, dan densitas 0,944 g/cm3. Hasil sintesis gliserol ester terbaik digunakan untuk aditif biodiesel B50 dengan uji stabilitas penyimpanan selama 3 bulan pada suhu 25, 12, dan 42oC. Parameter ujinya adalah angka asam, viskositas kinematis, korosifitas, dan kadar air. Nilai angka asam dari variasi jenis dan konsentrasi aditif masih memenuhi standar SNI 7182-2015 (0,5 mg KOH/g sampel) dengan rentang nilai 0,148-0,392 mg KOH/g sampel. Viskositas kinematis memiliki rentang nilai 3,12- 3,58 cst yang juga memenuhi standar SNI 7182-2015 (2,3-6 cst). Laju korosifitas tertinggi ada pada minggu ke-1 sebesar 0,447 mpy (GE) dan 0,261 mpy (DEE). Kadar air tertinggi pada hari ke-18 (0,046%), aditif GE 1000 ppm dan kontrol, yang artinya penambahan aditif dapat mempertahankan kadar air pada biodiesel B50. Secara keseluruhan variasi jenis aditif dan konsentrasi memenuhi standar SNI biodiesel 7182-2015. Berdasarkan hasil uji ANOVA dan Duncan (α = 0,05) menunjukkan bahwa suhu sintesis berpengaruh nyata pada rendemen. Suhu sintesis 140oC menghasilkan rendemen yang berbeda nyata, sedangkan suhu 160oC, 180oC, dan 240oC tidak berbeda nyata. Suhu sintesis berpengaruh nyata terhadap angka asam dan viskositas. Uji stabilitas penyimpanan menunjukkan perlakuan jenis, konsentrasi aditif, dan suhu penyimpanan berpengaruh nyata pada angka asam dan viskositas. Uji laju korosifitas menunjukkan bahwa jenis aditif berpengaruh nyata terhadap laju korosifitas. Faktor jenis dan konsentrasi aditif juga berpengaruh nyata pada kadar air, interaksi kedua faktor tersebut mulai terlihat pada hari ke 24., Fatty Acid Methyl Ester (FAME) is a biodiesel currently used in Indonesia. However, the obstacles of mixing FAME with diesel oil: FAME separates from diesel oil at low temperatures. Physicochemical properties also lead to a decrease in the quality of biodiesel during storage due to dissolved oxygen can possibly damage the engine. The addition of glycerol ester (GE)-based additives can solve this problem. This investigation consists of two phases. The first step is to synthesize GE by reacting 99.9% glycerol with oleic acid (1:1 mol/mol) using
Keyword: FAME, fisiko kimia, higroskopis, pencampuran, diesel oil, diesel oil, FAME, hygroscopic, mixing, physicochemical

Judul: Optimasi Waktu Reaksi, Suhu Reaksi dan Konsentrasi Katalis pada Sintesis Gliserol Tert-Butyl Eter (GTBE).
Abstrak: Biodiesel is one of the fuels that many countries develop because it’s renewable and eco-friendly. Biodiesel is used to substitute petroleum fuel especially diesel fuel. However, biodiesel still have disadvantages, that is the biodiesel’s cloud point and pour point is higher than petroleum based diesel fuel. This disadvantage becomes a problem on biodiesel utilization especially in subtropical countries. This problem can be solved by addition of chemicals to prevent agglomeration of crystals that are formed in biodiesel in low temperature. Increasing production of biodiesel cause increasing biodiesel by products as well, one of the biodiesel by products is glycerol. Glycerol has characteristic as anti -freezing (cryoprotectant) but it can’t be added directly to fuel because of polarity difference, decomposition, and polymerization can rise consequential engine problems at high temparatures. Glycerol must be modified to derivatives that are compatible with diesel and biodiesel prior to be added to the fuel. The most obvious derivative of glycerol has an analogy in gasoline reformulation (oxygenated gasoline). Etherification of glycerol with isobutylene produce branched ether that can be mixed with biodiesel to make a fuel with lower viscosity and cloud point value below 0°C. Beside of using isobutylene, etherification of glycerol also can be done with tert -butyl alcohol (TBA). The commonly used catalyst in etherification of glycerol is commercial strong acid ion-exchange catalyst, such as Amberlist. In this research, the possibility to replace expensive Amberlist with local bentonite was evaluated. Natural bentonite was activated by hydrochloric acid (HCl) prior to use as catalyst. The effect and optimization of reaction time, temperature and concentration of catalyst to the concentration of produced GTBE was studied. Experimental design that used is central composite design, it is one kind of the Response Surface Methodology (RSM). Lower level for reaction time is 6 hours, temperature is 60C, and concentration of catalyst is 2.5%. Higher level for reaction time is 10 hours, temperature is 80C, and concentration of catalyst is 7.5%. The result showed that reaction time doesn’t have signification influence to concentration of GTBE in confidence interval 95 %. Whereas , temperature and concentration of catalyst have signification influence s to concentration of GTBE in confidence interval 95 %. The result from analysis with software Design Expert 7.1.6 (free trial) shows that the relationship between reaction time (X 1), temperature (X2), and concentration of catalyst (X3) generate saddle point model. From optimization t est, the sqrt GTBE’s value is predicted 613.10 with reaction time is 4.9 hours, temperature is 66.2C and concentration of catalyst is 9 .7 %. Verification of that prediction of optimum condition resulted in sqrt GTBE’s value of 980. 86. This result showed that the model couldn’t predict the optimum condition of GTBE reaction, since the optimum point was out of the range. Optimum concentration of GTBE was predicted when reaction time below 6 hours, temperature above 60°C, and concentration of catalyst above 7 .5 %. The GTBE effectiveness test to reduce biodiesel’s cloud point and pour point was done by mixing GTBE in biodiesel with volume ratio 1:10. The result from this test showed that biodiesel
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Judul: Anatomi Otot Wajah Kancil (Tragulus napu)
Abstrak: Kancil merupakan hewan ruminansia terkecil di dunia yang mulai banyak digunakan sebagai model untuk penelitian ternak ruminansia besar. Untuk mengetahui sejauh mana kancil dapat digunakan sebagai hewan model penelitian diperlukan data-data ilmiah yang bersifat biologis dari hewan ini. Untuk itu dilakukan studi anatomi otot wajah terhadap 6 ekor kan- cil (Tragulus napu). Hasil penelitian menunjukkan bahwa kancil mempunyai bentuk dan susunan otot-otot wajah yang lebih mirip dengan kambing dan domba daripada sapi. Disamping itu didapatkan pula satu otot yang keadaannya mirip dengan M. retractor anguli oculi pada anjing…
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