Judul: Briket Arang Serbuk Kayu Sengon Berperekat Limbah Pengolahan Resin Pinus
Abstrak: Sengon wood sawdust is a potential resource of renewable energy. Its calorific value can be increased through charcoal briquetting. Unclassified Pine Rosin from the waste of pine resin processing was used as the briquette binder. The binder was expected to increase briquette durability and calorific value. In this study, the briquettes were prepared by mixing sawdust charcoal sengon and waste processing pine resin with various composition (G20, G25, and G30%). Briquetting performed by hot compression method with variation of temperature (120, 140, and 160oC) and time (15 and 20 min). Moisture content, density, volatile matter, ash content, fixed carbon and calorific value of briquettes determined according to ASTM D 5142-02. The durability of briquettes determined according to ASABE standard procedures and its combustion behaviour was examined by Thermogravimetry and Differential Thermal Analysis (TG-DTA). Data were analyzed using completely randomized design. The results showed that the density, moisture content, durability, volatile matter, ash content, fixed carbon, and calorific value of the resulting briquette was of 0.69- 0.86 g/cm3, 4.63-7.35%, 36.64-83.73%, 32.26-41.59 %, 4.11-6.02%, 46.63- 54.53%, 6014-6312 kcal/kg, respectively. Thermal analysis showed that during briquette combustion, the water loss occurred at 39-100oC, materials decomposition at 100-480oC with the weight loss of 15.8-65.4%, and no further weight loss occurred above the temperature of 428 oC. An acceptable charcoal briquette quality can be resulted with the addition of 30% rosin briquetting at 160oC C for 15 minutes
Keyword: Bogor Agricultural University (IPB), durability, thermal behaviour, resin, sengon, charcoal briquette

Judul: Pemanfaatan Limbah Tebu sebagai Bahan Briket Arang
Abstrak: The potentially biomass waste of sugarcane as an alternative energy is abundance but has not fully processed. This research propose on the processing of sugarcane waste as an alternative energy such as carbon briquettes. Carbonazation is done by using a modified drum furnace. The obtained carbon was then milled into a powder form, filtered using a 80 mesh sieve and the carbon that passes from the filter is mixed with tapioca adhesive levels of 2.5% and 5%. The raw materials manually compressed using a hydraulic system at a pressure of 20 tons, then dried in an oven at 70 C for 48 hours. Carbon briquettes produced in general result in physical properties are better than the raw one. Water content ranges from 0.475, ash content of 9.164 %, levels of substance evaporates 15.440 %, bonded carbon content 75.395 %, density, firmness press 82.04 kg/ and calorific value 6219 cal / gram. The addition of starch adhesives will affects the quality of carbon briquettes in physical and chemical properties. Carbon briquette with good quality found on the additional adhesive with a concentration of 5%.
Keyword: Bogor Agricultural University (IPB), sugarcane waste., heat value, compressive strength, Carbon briquettes

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