Judul: Determination of Grass Waste Biopellet Formulation with West Indian Elm Sawdust Mixture (Guazuma ulmifolia)
Abstrak: Limbah rerumputan dan serbuk kayu jati belanda berpotensi sebagai sumber energi berkelanjutan untuk memenuhi kebutuhan energi yang kian meningkat. Salah satu sumber energi tersebut adalah bahan bakar padat berupa biopelet. Penelitian ini bertujuan untuk menentukan formulasi bioepelet terbaik dari campuran limbah rerumputan dan serbuk kayu jati belanda. Pembuatan biopelet limbah rerumputan dan serbuk kayu jati belanda menggunakan pelletizer tipe rotary dies dengan perbandingan formulasi diantaranya A1 (100% limbah rerumputan), A2 (70% limbah rerumputan : 30% serbuk kayu jati belanda), A3 (65% limbah rerumputan : 35% serbuk kayu jati belanda), A4 (60% limbah rerumputan : 40% serbuk kayu jati belanda), A5 (55% limbah rerumputan : 45% serbuk kayu jati belanda), A6 (50% limbah rerumputan : 50% serbuk kayu jati belanda), dan AN (100% serbuk kayu jati belanda). Formulasi campuran terbaik terdapat pada formulasi A3, yaitu dengan komposisi 65% limbah rerumputan dan 35% sebuk kayu jati belanda. Pemilihan formulasi terbaik didasarkan pada standar SNI 86752018 meliputi nilai kalor yang tinggi sebesar 17,76 MJ/kg, kadar air yang rendah sebesar 4,24%, kerapatan bahan sebesar 0,61 g/cm3, ketahanan sebesar 95,76%, kadar abu sebesar 6,54%, kadar zat terbang sebesar 72,38% dan laju pembakaran sebesar 2,58 kg/jam., Waste grass and west Indian elm sawdust have the potential as a source of sustainable energy to meet the increasing energy needs. One of these energy sources is solid fuel in the form of biopellets. This study aims to determine the best biopellet formulation from a mixture of grass waste and west Indian elm sawdust. Making biopellet from grass waste and west Indian elm sawdust using rotary dies pelletizer with a formulation ratio including A1 (100% grass waste), A2 (70% grass waste : 30% west Indian elm sawdust), A3 (65% grass waste : 35% west Indian elm sawdust), A4 (60% grass waste: 40 % west Indian elm sawdust), A5 (55% grass waste : 45% west Indian elm sawdust), A6 (50% grass waste : 50% west Indian elm sawdust), and AN (100% west Indian elm sawdust). The best mixed formulation is found in the A3 formulation, which is with a composition of 65% grass waste and 35% west Indian elm sawdust. Selection of the best formulation is based on the SNI 8675-2018 standard includes high calorific value of 17.76 MJ/kg, low moisture content of 4.24%, material density of 0.61 g/cm3, resistance of 95.76%, ash content of 6.54%, volatile matter content of 72.38% and combustion rate of 2.58 kg/hour.
Keyword: biopelet, limbah rerumputan, serbuk kayu jati belanda, pelletizer tipe rotary dies

Judul: Study of Biopellet Formulation Based on Albasia Wood Powder with a Mixture of Straw and Rice Husk Charcoal
Abstrak: Serbuk kayu albasia dan limbah padi merupakan salah satu sumber bahan bakar alternatif potensial berasal dari biomassa yang dapat dimanfaatkan menjadi biopelet sebagai solusi pemanfaatan limbah. Tujuan penelitian ini adalah menganalisis dan mengetahui karakteristik biopelet berbahan dasar serbuk kayu albasia dengan campuran jerami dan arang sekam serta mengetahui komposisi formulasi terbaik dari bahan dasar biopelet tersebut sebagai energi bahan bakar alternatif. Pembuatan biopelet menggunakan pelletizer tipe fixed dies dengan perbandingan formulasi bahan baku yaitu A0 (arang sekam 90% : perekat 10%), A1 (jerami padi 90% : perekat 10%), A2 (serbuk kayu albasia 90% : perekat 10%), A3 (serbuk kayu albasia 25% : jerami 25% : arang sekam 40% perekat 10%), A4 (serbuk kayu albasia 25% : jerami 40% : arang sekam 25% : perekat 10%), dan A5 (serbuk kayu albasia 40% : jerami 25% : arang sekam 25% : perekat 10%). Perlakuan terbaik biopelet diperoleh pada komposisi serbuk kayu albasia 90% dan perekat 10% berdasarkan nilai kadar air 10,62%, kadar abu 1,83%, dan kerapatan apparent 0,725 g/cm3 yang memenuhi standar SNI 8675:2018. Nilai kalor dari biopelet tersebut yaitu 17,16 MJ/kg., Albasia sawdust and rice waste are potential alternative fuel sources derived from biomass that can be used as biopellets as a solution for waste utilization. The purpose of this study was to analyze and determine the characteristics of biopellets made from albasia wood powder with a mixture of straw and husk charcoal and to determine the composition of the best formulation of these biopellets as alternative fuel energy. Making biopellets using a fixed dies type pelletizer with a ratio of raw material formulations, namely A0 (90% husk charcoal : 10% adhesive), A1 (90% rice straw : 10% adhesive), A2 (90% albasia wood powder : 10% adhesive), A3 (25% albasia wood powder : 25% straw : 40% husk charcoal : 10% adhesive), A4 (25% albasia wood powder : 40% straw : 25% husk charcoal : 10% adhesive), and A5 (40% albasia wood powder : 25% straw : 25% husk charcoal : 10% adhesive). The best treatment for biopellet was obtained at the composition of 90% albasia wood powder and 10% adhesive based on the value of water content of 10,62%, ash content of 1,83%, and apparent density of 0,725 g/cm3 which meet the standards of SNI 8675:2018. The calorific value of the biopellet is 17,16 MJ/kg.
Keyword: albasia sawdust, biopellet, fixed dies pelletizer, husk charcoal, rice straw

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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