Judul: Arang Aktif Berbasis Kulit Buah Malapari (Pongamia pinnata) sebagai Adsorben dalam Penangan Limbah Batik
Abstrak: Vegetable oil production of malapari (Pongamia pinnata) fruit leaving unprocessed waste. The purpose of this study was to use malapari fruit peel as raw material for preparing activated charcoal, characterizing, and applying the best quality activated charcoal produced as adsorbent for dyes of batik industry waste water. Some samples treated through carbonization at temperature of 450 ℃ and continued activation with phosphoric acid 2% and physical activation at 750 ℃ with flow steam for 60 minutes resulted the best quality of activated charcoal with methylene blue adsorptivity of 120 mg/g. Leaching with HCl 10% was able to increase methylene blue adsorptivity up to 193 mg/g which meet SNI 06-3730- 1995 requrement with specific surface area and pore surface area of 715 m2/g and 138 μm2,respectively. Indigosol dye adsorption by the best quality charcoal followed the Freundlich isotherm. The activated charcoal was able to reduce intensity of the dye in the waste water and the chemical oxygen demand of 98.51% and 97.43%, respectively.
Keyword: Bogor Agricultural University (IPB), malapari, batik dye waste water, activated charcoal

Judul: Pemanfaatan biji alpukat untuk pembuatan arang aktif sebagai adsorben alternatif zat warna pada limbah cair batik
Abstrak: Avocado seeds are agricultural waste containing starch that is potential to be used as raw materials for activated carbon. The purpose of this experiment is to produce an activated carbon from avocado seeds and to be applied for adsorbing remazol dyes on batik effluent. This study performed 2 types of activation, i.e. chemical and physical activations. Chemical activation was performed by submerging the charcoal in KOH 30% and H3PO4 30%, while physical activation performed by steaming at 700 oC for 60 and 90 minutes. The activated carbon with the highest iodine number (AB60) was used to adsorb dyes in batik effluent. The result showed that activated carbon from avocado seeds have a relatively low ability to adsorb dye, as evaluated from the lowering color concentration of remazol dye by 42% in the batik effluent.
Keyword: Bogor Agricultural University (IPB), remazol, batik effluent, avocado seeds, adsorption, active carbon

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