Judul: Pemisahan dan Pencirian Amilosa-Amilopektin pada Tepung Tapioka dan Sagu Menggunakan Ragam Suhu Air
Abstrak: Amylose can be easily separated by using water with several temperature condition. Separation amylose and amylopectin process is done by using not only hot water with different temperature 55, 60,and 65 °C, but also with different rasio 1:30, 1:45, and 1:60. The characteristics that observed in this study were water contain, viscosity, molecular weight, and thermal analysis using differential scanning calorymeter. The yield of amylose from tapioca obtained in this study were 15−17% (60 °C), and 21−23% (65 °C) but there is no yield obtained on 55 °C, meanwhile the yield of amylose from sagoo obtained were 13−16% (60 °C), and 22−23% (65 °C). The characteristics of amylose and amylopectin, both obtained from tapioca and sagoo had met standard range so there is no purified anymore.
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Judul: Pemisahan dan Pencirian Amilosa dan Amilopektin dari Pati Jagung dan Pati Kentang pada Berbagai Suhu
Abstrak: Amilose can be separated from amylopectin based on their distinct properties. Amylose is more crystaline, while amylopectin is amorphous. Separation was done by heating a solution of corn and potato with a ratio of 1:30, 1:45, 1:60 at 53, 55, 57oC for potato starch and 60, 70, 72 oC for corn starch for 1.5 hours. The results showed that amylose could be separated from amylopectin simply by using hot water. The results showed that temperature wais more influencing on the separation of amylose-amylopectin. The best separation results were at 60 °C and the ratio of 1:60 for corn starch with molecular weight 5.6919 × 105 g/mol for amylose and 81.2783 × 105 g/mol for amylopectin and at a temperature of 53 °C and the ratio of 1:60 for potato starch with molecular weight 4.2688 × 105 g/mol for amylose and for amylopectin 61.6797 × 105 g/mol. The temperature and the ratio of amylose : amylopectin obtained were closely similiar to those published in literatures. From the results obtained by DSC measurements the glass transition point at 1:60 ratio was at 70.10 oC for potato starches at temperature 57 oC and 40.76 oC for corn starch at 72 oC.
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Judul: Dynamical System of Hepatitis B in Three Groups with Vaccination
Abstrak: The aim of this study is to modify the hepatitis B transmission model in three age groups involving vaccination from the model conducted by Zhoe and Zhang.The method used is to analyze the stability of the fixed point and its basic reproduction number (R_0). Performed stability analysis and numerical simulation to see population dynamics. Next, a sensitivity analysis of the parameters was carried out to see its effect on R_0. From the analysis obtained two fixed points, namely non-endemic and endemic fixed points. Non-endemic fixed points are locally asymptotically stable if R_0 <1 Meanwhile, the endemic fixed point is locally asymptotically stable if R_0 > 1. Hepatitis vaccination affects the number of susceptible population, because the more successful the vaccination, the smaller the number of susceptible populations so that the smaller the population will be infected.
Keyword: Dynamic, Hepatitis B, Vaccine, Mathematical model