Judul: Pembuatan, pencirian, dan uji daya adsorpsi arang aktif dari kayu meranti merah (Shorea Sp.)
Abstrak: Wood of red meranti (Shorea sp.) is utilized widely as furniture and construction material and produces plenty of wood waste. In this research, the wood waste was used as activated charcoal raw material to improve its utility. The activated charcoal produced was tested as absorbent in industrial chromium and manganese metal waste processing. Carbon activation was relied on 3 factors, namely activator chemicals, water vapour steam, and activation time. As the quality indicators of activated carbon Indonesian National Standard (SNI 06- 3730-1995) was used. The specific surface area and structure pattern of activated carbon were also determined. Commercial activated carbon was also studied as reference. The results showed that the best activated carbon based on iodine adsorption activity and SNI’s standard quality was carbon activated with water vapour steam for 90 minutes without activator chemicals (HCl 5%). The best activated carbon was capable to reduce chromium and manganese concentration up to 58.11 and 5.85%, respectively. The adsorption mechanism followed Freundlich isotherm, and the dosage obtained from the isotherm equation could reduce 99.99% of chromium concentration from industrial waste.
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Judul: Adsorptivitas arang aktif kayu meranti merah (Shorea sp.) terhadap fenol
Abstrak: Serbuk maupun serpihan kayu sisa hasil pengolahan kayu telah banyak dimanfaatkan sebagai adsorben. Penelitian ini memanfaatkan kayu meranti merah sebagai adsorben dalam menjerap limbah fenol. Proses aktivasi dilakukan dengan kombinasi metode fisis dan kimia. Kondisi terbaik diperoleh dengan NaOH 0.75% dan pengaliran uap air selama 50 menit. Kapasitas adsorpsinya 7.7−23.6 g/g dengan efisiensi adsorpsi 89−92%. Mekanisme adsorpsi mengikuti isoterm Freundlich dengan linearitas 99.24%. Kualitas arang aktif tersebut juga telah memenuhi persyaratan dalam Standar Nasional Indonesia 06-3730-1995 dan lebih baik dibandingkan dengan arang aktif komersial.
Keyword: Bogor Agricultural University, Institut Pertanian Bogor, IPB, Meranti merah, Arang aktif, Fenol, Sdsorpsi, Limbah, Kapasitas adsorpsi

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