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: 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: Approximation of the Median of Poisson Distribution Using the Relation of Poisson-Gamma Distribution
Abstrak: A major drawback of median is that median cannot usually be defined in closed form, even in the cases where their distribution functions are known. This study gives an approximation of the closed form for the median of the Poisson distribution by using the relation of Poisson-Gamma distribution. The approximation uses elementary techniques based on the monotonicity of certain sequences involving tail probabilities of the Poisson distribution and the Central Limit Theorem. Furthermore, a closed form expression for the mean absolute deviation 􀜧|􀜰􀰒 􀵆 􀜯􀝁􀝀􁈺􀜰􀰒􁈻| is also studied. The median is relevant because of the fact that it minimizes the mean absolute deviation of a Poisson random variable (􀜰􀰒􁈻 by considering median as central tendency.
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