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: Pembuatan Briket Arang Dari Campuran Kulit Kacang, Cabang Dan Ranting Pohon Sengon Serta Sebetan Bambu
Abstrak: Introduction. One of waste utilization or organic garbage is as raw material of charcoal briquette. Charcoal Briquette can support energy need of human. Charcoal Briquette can be made by material which contain lignin and cellulose like waste or organic garbage where can be got in human life like nutshell waste, logging waste of tree of sengon which has branches and sticks, and also waste of bamboo slice. Making charcoal briquette which comes from waste or organic garbage can be alternative solution for solving garbage and can be new alternative sources of energy. Method. Making charcoal briquette is prepared raw material at first. It is continued by processing combustion with kiln drum (temperature at 500oC-1000oC). Next, it uses crashing and buffering charcoal (filter at 35 meshs) to become dust which has charcoal size of 35 meshs or more. Making starch glue (5% derived from charcoal weight) is mixing and cooking tapioca flour with water (1:12). Charcoal Dust is mixed with starch glue and it will be printed by pressure at ± 9 tons to become charcoal briquette. Then, briquette is tested physical in properties (water content, density and pressure stability) and chemical characteristic ( ash content, volatile matter content, content of bounded carbon, calorie value). Result and Discussion. Result of test in physical and chemical properties of charcoal briquette showed water content average of 1,57%-2,18%, ash content of 10,92%- 15,09%, volatile matter content of 19,28%-41,36%, content of bounded carbon of 44,32%-66,48%, density of 0,40 g/cm3-0,53 g/cm3, pressure stability of 9,99 kg/cm2- 15,89 kg/cm2, and calorie value of 5175 cal/g-6299 cal/g. Conclusion. Mixing nutshell charcoal, branch and tree stick of sengon and bamboo slice could be made for briquette and it had high enough value in calorie (5175kal/g -6299 kal/g). Four briquettes which had been produced were only briquette of Nutshell charcoal of Bamboo Sengon (KKSB) which got quality standard of Japan charcoal briquette at calorie value (6299 cal/g). But, Four briquettes didn’t get standard of charcoal briquette of America, Indonesia and UK. Composition of mixture-charcoal influenced charcoal density and calorie value. Composition of mixture-charcoal didn’t effect charcoal water content, ash content, volatile matter content, content of bounded carbon and pressure stability value.
Keyword: 

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