Judul: Torrified Biopellet of Coconut Husk
Abstrak: Kepadatan energi sabut kelapa dapat ditingkatkan melalui proses torefaksi. Penelitian ini bertujuan untuk mengetahui mutu biopelet sabut kelapa yang ditorefaksi pada suhu dan waktu torefaksi yang beragam. Mutu biopelet ditentukan berdasarkan kadar air, kadar abu, zat terbang, karbon terikat, kerapatan, ketahanan dan nilai kalor yang mengacu pada standar DIN EN 14961-2 dan SNI 8021-2014. Secara umum biopelet yang dihasilkan telah memenuhi standar SNI 8021-2014. Hasil penelitian menunjukkan bahwa biopelet memiliki kadar air sebesar 5,41-5,54%, zat terbang sebesar 31,88-32,25%, kadar abu sebesar 2,95-3,26%, karbon terikat sebesar 59,26-59,45%, kerapatan sebesar 0,91- 1,02 g/cm3, ketahanan sebesar 93,57-93,81%, dan nilai kalor sebesar 4.454-4.923 kkal/kg. Torefaksi biopelet sabut kelapa pada suhu 300oC selama 15 menit mampu meningkatkan nilai kalor sampai dengan 4.923 kkal/kg, The energy density of coconut husk can be increased through torefaction process. This research was intended to determine the quality of coconut husk biopelet torefied at various temperatures and retention times. Biopelet quality parameter was determined based on moisture content, volatile matter, ash content, fix carbon, density, durability, and heating value refered to the standards of DIN EN 14961-2 and SNI 8021-2014. In general, the biopellet produced have met the SNI 8021-2014 requirements. The results showed that the biopellets had a moisture content of 5,41-5,54%, a volatile matter of 31,88-32,25%, an ash content of 2,95-3,26%, a fix carbon of 59,26-59,45%, a density of 0,91-1,02 g/cm3, a durability of 93,57-93,81%, and a heating value of 4.454-4.923 kcal/kg. Torefaction of the biopelet at 300oC for 15 minutes increased the heating value up to 4.923 kcal/kg.
Keyword: Biopelet, coconut husk, torrefaction, bioenergy

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: 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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