Judul: Biopelet Kayu Agathis dengan Penguat Kulit Lepasnya
Abstrak: The agathis bark is expected to increase the energy content and durability of the resulting biopellet. The present research was aimed to analyze chemical components of agathis and to determine the quality of agathis wood biopellet fortified with its loosen bark. The klason lignin, extractives, holocellulose and α- cellulose content of wood and bark of the agathis were determined following the standard procedures of TAPPI T 222 0m-88, TAPPI T 204 0m-88, and Browning (1967), respectively. Biopellets of 15 mm diameter were prepared with pelletizing pressure of 1500 psi. The moisture content, ash content, density, durability, and calorific value of the resulting biopellet were compared to those required by DIN EN 14961-2 and 51731 standards. The α-cellulose and holocellulose content of the agathis bark were found lower than these of its wood. However, its klason lignin, extractive, and ash content were higher than these of its wood. The resulting biopellet retained the density of 0.61-0.71 g/cm3, moisture content of 0.42-4.52%, ash content of 0.79-2.73%, durability of 21.26-44.59%, and calorific value of 4524- 4628 kcal/kg. Except for that of the biopellet density and durability, all parameters satisfied the requirements of DIN EN standards. Thermal analysis of biopellet showed that water loss occurred at 36-100 oC and significant mass decomposition between 100 up to 475 oC with the weight loss of 77.34-80.51%. No further decomposition was found at above 480 oC.
Keyword: Bogor Agricultural University (IPB), thermal, bark, biopellet, agathis

Judul: Pemanfaatan Limbah Kelapa Sawit (Elaeis guineensis Jacq.) dan Serbuk Kayu Mahoni sebagai Bahan Baku Biopelet
Abstrak: Despite widely known for its use as food, palm’s wastes produced by the plantation aren’t optimally used yet. Palm waste has potential to be made into fuel, one of which is biopellet. This research aims to find out the biopellet’s characteristic made from palm waste and examine the effect of augmenting mahoni sawdust toward biopellet’s quality. Materials used are exterior part of palm plant’s trunks, interior part of palm’s trunks, palm’s midrib, leaves, and mixed materials such as mahoni sawdust (0%, 15%, 30%, 50%). Biopellet was made using 40-60 mesh particle and compressed in 200 oC temperature for 15 minutes. Biopellet characteristics were examined using SNI 06-4369-1996 and SNI 01-2891-1992 standard. Research results show that biopellet’s water content is 0.14% - 2.34%, with volatile matter 62.34% - 76.29%, 1.12% - 13.32% ash content, 0.65 g/cm3 – 0.94 g/cm3 density, calor value as much as 4269.27 cal/g – 4729.99 cal/g, sulphur content 0.012% - 0.038%, nitrogen 0.290% - 1.95%, and chlorine content < 0.01%.
Keyword: calor value, biopellet, sawdust, oil palm

Judul: Tinjauan Matematis pada Model Makroskopik dan Mikroskopik Arus Lalu-lintas
Abstrak: Traffic flow phenomenon can be described through mathematical model such as continuous dynamic model with an ordinary differential equation so that it can be solved with integral factors. In this paper three simple models of traffic flow are discussed, i.e, two macroscopic and one microscopic models. Macroscopic model formulates dynamics of the traffic flow that occurs on a large number of vehicles on a road. While the microscopic model explains drivers’ behavior in their interaction with other vehicles ahead, i.e, car-following model. This paper shows the existence of ordinary differential equation found in the traffic flow model and indicates some different representations in the context of the same model. It also reviews a simple model of traffic flow along a single link, which leads to some unexpected results, i.e, it can express the solution model in term of link outflows as well as trip time. In the microscopic model, simulation is done to illustrate the behavior of the drivers with a sensitivity coefficient as a benchmark parameter.
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