Judul: Analisis Briket Arang Berbahan Dasar Limbah Organik Padat Sebagai Bahan Bakar Alternatif
Abstrak: Penelitian ini bertujuan untuk mengetahui mutu briket arang berbahan dasar tempurung kelapa, serbuk gergaji kayu jati dan sekam padi berdasarkan standar SNI dengan parameter kadar air, kadar abu, kadar zat menguap dan kadar karbon serta variasi komposisi bahan baku terbaik terhadap mutu briket arang yang dihasilkan. Briket arang dibuat dengan cara konvensional dengan komposisi arang tempurung kelapa, serbuk gergaji kayu jati dan sekam padi yang berbeda serta penambahan perekat kanji. Hasil penelitian menunjukkan mutu briket arang sebagai berikut, kadar air 28,09 - 33,07 %, kadar abu 24,06 - 31,16 %, kadar zat menguap 2 – 18 % dan kadar karbon 53,45 – 70,41 %., This study aims to determine the quality of charcoal briquettes made from coconut shell, teak sawdust and rice husks based on SNI standards with parameters of water content, ash content, volatile matter content and carbon content as well as variations in the composition of the best raw materials on the quality of the produced charcoal briquettes. Charcoal briquettes are made in a conventional way with different compositions of coconut shell charcoal, teak sawdust and rice husks and the addition of starch adhesive. The results showed the quality of charcoal briquettes as follows, water content 28,09 – 33,07 %, ash content 24,06 – 31,16 %, volatile matter content 2 – 18 % and carbon content 53,45 - 70,41 %.
Keyword: coconut shell, teak sawdust, rice husk, charcoal briquettes

Judul: Biobriket Limbah Padat Organik Sebagai Bahan Bakar Alternatif
Abstrak: Biobriket adalah biomassa yang dipadatkan agar diperoleh bentuk yang lebih seragam daripada biomassa. Bahan baku biobriket yang digunakan adalah limbah padat organik rumah tangga dan serbuk kayu sengon. Tujuan dari penelitian ini adalah memanfaatkan limbah padat organik sebagai bahan baku biobriket, mengetahui sifat fisis dan kimia serta karakteristik pembakaran biobriket yang dihasilkan, dan menentukan mutu biobriket. Hasil penelitian menunjukkan sifat fisis dan kimia biobriket yang dihasilkan yaitu kadar air 9.46%, kerapatan 0.55 g/cm³, kadar abu 9.24%, nilai kalor 4899.17 kal/g, unsur karbon 44.47%, unsur hidrogen 6.02%, unsur oksigen 48.29%, unsur nitrogen 0.99%, dan unsur sulfur 0.2%. Kualitas panas biobriket yang dihasilkan termasuk baik, suhu maksimal bara biobriket mencapai 586˚C. Mutu biobriket yang dihasilkan sudah cukup baik berdasarkan standar mutu briket arang kayu di Indonesia.
Keyword: biobriket, limbah padat organik rumah tangga, serbuk kayu sengon

Judul: Dynamical System of Hepatitis B in Three Groups with Vaccination
Abstrak: The aim of this study is to modify the hepatitis B transmission model in three age groups involving vaccination from the model conducted by Zhoe and Zhang.The method used is to analyze the stability of the fixed point and its basic reproduction number (R_0). Performed stability analysis and numerical simulation to see population dynamics. Next, a sensitivity analysis of the parameters was carried out to see its effect on R_0. From the analysis obtained two fixed points, namely non-endemic and endemic fixed points. Non-endemic fixed points are locally asymptotically stable if R_0 <1 Meanwhile, the endemic fixed point is locally asymptotically stable if R_0 > 1. Hepatitis vaccination affects the number of susceptible population, because the more successful the vaccination, the smaller the number of susceptible populations so that the smaller the population will be infected.
Keyword: Dynamic, Hepatitis B, Vaccine, Mathematical model