Judul: Ciri kimiawi asam resin kopal  Agathis loranthifolia
Abstrak: Copal is originated from exudate of Agathis loranthifolia trees, which flows out from the tapping. Indonesian copal includes manila copal, is divided into four groups among others: bua, loba, melengket and Pontianak copal. Research of resin acid from copal has not been widely studied. Therefore, purpose of this study is to identify resin acids of copal from Sukabumi and Ternate area. Extraction was done using acetone:MeOH (9:1) solvent, followed by fractionation using some solvents, i.e. n-hexane, ethylacetate, H2 O, and acetone:MeOH (9:1). Identification was done using gas chromatography-mass spectrometer (GCMS). The quality of copal was evaluated based on SNI 7634-2011. Resin acids copal from Sukabumi identified by GCMS are 44% limonene, ethylene oxide hexamer, cis-limonene oxide, toluene, trans-carveol, 2-siclohexane-1-one, trans-limonene oxide, and alpha pinene. Copal from Ternate are 37% limonene, ethylene oxide hexamer, preludin, toluene, carveol 1, 2-siclohexane-1-one, acetat acid, hexaethylen glycol, champhen, and trans-limonene oxide. However, fractionation of the copal converted resin acids to 100% carvone. These results suggest that limonene are easily oxidized to carvone. Properties of manila copal from Sukabumi and Ternate fall to the first class, and are possible to be improved to the premium class by removing some dirt compount.
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Judul: Identifikasi komponen kimia empat tingkat mutu gaharu
Abstrak: Agarwoods (Aquilaria malaccensis) with 4 different commercial grades has been identified, namely kacangan B, teri B, medang A, and medang B, from the highest to the lowest grade. In this work, resin content tends to increase as the grade increases. However, the resin content does not have correlation with the content of sesquiterpene and chromone which determine the grade of agarwoods. In isolation step, the agarwood samples were fractionated using gradient column chromatography method with hexaneethyl acetate as eluent and were grouped according to its Rf point. Identification of samples using gas chromatography-mass spectrophotometer showed the presence of 10 sesquiterpenes and 3 chromones in various levels.
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Judul: Pengaruh vaksinasi terhadap dinamika populasi pada model SIR (Susceptible-Infected-Recovered)
Abstrak: SIR model can be used to model the spread of diseases in a closed population based on certain assumptions. In this research, the SIR model is formulated by including the factor of vaccination. As the result, the model has been shown to have two equilibrium points, i.e. disease free and endemic equilibrium. A simulation study is carried out to illustrate the model. The results show that some equilibrium points are asymptotically stable. Moreover, a minimum level of vaccination has been defined. For the vaccination level less than the minimum level, increase in the vaccination level results in decrease of the proportion of infected individuals in the corresponding equilibrium point. On the other hand, for the vaccination level greater than the minimum level, increase in the vaccination level results in decrease the proportion of susceptible individuals in the corresponding equilibrium point. Furthermore, when vaccination level is greater than the minimum level, it is found that the time needed for the disease to extinct is shorter.
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