Judul: Metil Ester Gondorukem sebagai Kandidat Bahan Bakar Nabati
Abstrak: The objective of this research is to produce ester of rosin distillate using methanol and H2SO4 (pa) as a catalyst. The result showed an optimum yield of methyl ester was 88.5% at an operating condition of 1.2 mL catalyst in 1.5 hours. The infrared spectra showed that carboxyl groups was replaced by C=O ester group, proofing that the rosin distillate was esterified. Furthermore, the gas chromatography-mass spectrometer spectra showed that the resin acids consists of ester derivates of abietic acid, sandaracopimaric acid, dehidroabietic acid, isopimaric acid, palustric acid. Based on SNI 04 -7182-2006, the kinematic viscosity at 40ºC (4.2 mm2/s), cloud point (-18ºC), total sulfur (67 ppm), acid number (0.1 mg-KOH/g), iodine number (12.8%), and total alkyl ester (99.8%), the methyl ester of pine rosin would be feasible to be used as a biodiesel material. The flash point was considered too low for biodiesel, but would be suitable f or biogasoline.
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Judul: Rasio Molar dan Konsentrasi Katalis Methyl Ester Sulfonic Acid pada Proses Sintesis Gliseril Ester
Abstrak: Glycerol is a by-product of biodiesel industry production which still can be further processed into more value-added products. The example is the utilization of glycerol by means of esterification between glycerol and oleic acid with methyl ester sulfonic acid (MESA) catalyst, producing glyceril ester. The purpose of this study was to obtain the conditions of esterification with variable factors were molar ratio between oleic acid and glycerol and the concentrations of added MESA catalyst. Before esterification, crude glycerol was purified by adding 5% (v/v) phosphoric acid 85%, producing glycerol with ±80% glycerol content. Furthermore, glycerol was then esterified with supply of nitrogen, at temperature of 180 °C, and the stirring speed of 400 rpm for 90 minutes. The best combination of molar ratio and concentration of catalyst MESA is on ratio molar 0,8:1 (glycerol : oleic acid) with 0,5% added of catalyst MESA. Esterification on that condition produced glyceryl ester with the yield of 79,55%, density 0,940 g/cm3, acid value 44 mg KOH/g sample, viscosity 90 cP (30 oC), kinematic viscosity 49,04 cSt (40 oC), flash point 206 oC, pour point -1,5 oC, and boiling point 105 oC.
Keyword: Bogor Agricultural University (IPB), glyceryl ester, esterification, MESA, glycerol

Judul: Analisis Model Pandemik dan Prepandemik Avian Influenza pada Populasi Manusia
Abstrak: Avian influenza is a viral disease caused by a virus within the subtype of H5N1 in which its transmission caused by birds or human. In human population, transmission process of avian influenza is discussed in the model called: bird model, prepandemic model and pandemic model. The bird model has two equlibrium points. These are saddle disease free equilibrium and stable endemic equilibrium. The endemic equlibrium occurred when the reproduction number of avian influenza is greater than one. In the endemic equilibrium, avian influenza may infect both bird and human. The prepandemic model has two equilibrium points. These are avian influenza dominant equilibrium and human influenza dominant equilibrium. The human influenza dominant equilibrium occurred when the reproduction number of human influenza is greater than one. The pandemic model has one pandemic equlibrium. The human influenza pandemic occurred when the ratio of human influenza invasion, pandemic invasion and the reproduction number of human influenza is greater than one, respectively. The avian influenza pandemic occurred when the ratio of human influenza invasion, pandemic invasion is less than one and the reproduction number of avian influenza greater than one, respectively.
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