Judul: Karakteristik Biopelet Torefaksi Limbah Tandan Kosong Kelapa Sawit dengan Fortifikasi Kayu Kaliandra (Caliandra callothyrsus) dan Kayu Gamal (Gliricidia sepium)
Abstrak: Biomassa dapat digunakan sebagai alternatif pengganti bahan bakar fossil. Pengembangan biomassa berfokus pada pengolahannya menjadi sumber energi terbarukan dengan kualitas tinggi. Salah satu teknik peningkatan mutu biomassa adalah dengan torefaksi, densifikasi, dan fortifikasi. Penelitian yang dilakukan bertujuan untuk mengetahui karakteristik biopelet tandan kosong kelapa sawit dengan fortifikasi kayu gamal dan kaliandra dengan 3 taraf persentase penambahan (10, 20, 30 %). Biopelet yang dihasilkan memiliki kadar air (1,403 – 2,236%), kadar zat terbang (58,008 – 65,344%), karbon terikat (22,232 – 23,676%) dan nilai kalor(4229 – 4331 Kcal/kg) yang telah memenuhi standar DIN EN 14961-2. Kadar abu (10,814 – 17,119%), kerapatan (0,816 – 0,950 g/cm3), dan ketahanan biopelet (86,890 – 91,070 %) yang dihasilkan belum memenuhi standar DIN EN 14961-2. Proses torefaksi dan fortifikasi TKKS mampu menghasilkan produk biopelet terbaik berupa biopelet terfortifikasi kayu kaliandra dengan taraf 10%., Biomass can be used as an alternative to fossil fuels. Biomass development focuses on processing it into a renewable energy source with high quality. One of the techniques to improve the quality of biomass is by torrefaction, densification and fortification. The aim of this study was to determine the characteristics of biopelet of empty oil palm fruit bunches with fortified gamal and calliandra wood with 3 percentage levels of addition (10, 20, 30 %). The resulting biopelets have moisture content (1.403 – 2.236%), volatile matter content (58.008 – 65.344%), bonded carbon (22.232 – 23.676%) and calorific value (4229 – 4331 Kcal/kg) which comply with DIN EN 14961- 2. Ash content (10.814 – 17.119%), density (0.816 – 0.950 g/cm3), and durability of the produced biopelets (86.890 – 91.070%) do not meet DIN EN 14961-2 standards. The torrefaction and fortification processes of OPEFB were able to produce the best biopelets in the form of calliandra wood fortified biopelets with a level of 10%.
Keyword: Densification, Fortification, Gamal, Kaliandra, Oil palm empty fruit bunches

Judul: Biopelet Torefaksi Kayu Kaliandra (Calliandra calothysrus).
Abstrak: Torefaksi biopelet dapat meningkatkan mutu biopelet seperti sifat hidrophobik dan kerapatan energi. Penelitian ini bertujuan untuk meningkatkan mutu biopelet kayu kaliandra dengan proses torefaksi. Serbuk kayu kaliandra berukuran 40-60 mesh dicetak menjadi biopelet tanpa menggunakan perekat dengan suhu kempa 180°C selama 10 menit kemudian dilakukan torefaksi. Torefaksi dilakukan pada suhu 200°C, 230°C, 260°C dan 290°C selama 1 jam. Karakteristik biopelet torefaksi diuji berdasarkan SNI 8021-2014. Hasil penelitian menunjukkan torefaksi meningkatkan mutu biopelet. Suhu torefaksi memberikan pengaruh nyata terhadap karakteristik biopelet (p<0.05). Peningkatan suhu torefaksi meningkatkan nilai kadar abu, kadar karbon terikat dan nilai kalor serta menurunkan nilai kadar air, kadar zat terbang, kerapatan, ketahanan dan rendemen biopelet yang ditorefaksi. Secara umum biopelet yang dihasilkan telah memenuhi syarat SNI 8021-2014. Nilai kadar air, kadar zat terbang, kadar karbon terikat, kadar abu, kerapatan, rendemen, ketahanan dan nilai kalor berturut-turut yaitu 1.98-2.78%, 62.58-77.51%, 18.87-34.17%, 0.84-1.27%, 0.83-1.17g/cm3, 71.68-97.62%, 32.18- 46.79%, 4516-5790 kkal/kg.
Keyword: biopelet, biomassa, kaliandra, torefaksi

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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