Judul: Biopelet dari Limbah Batang Sorgum (Sorghum bicolor L.)
Abstrak: Sorghum (Sorghum bicolor L.) is a potential cereal crop with a wide area of adaptation. The purpose of this study was to examine the physical quality of biopellet produced from the waste of sorghum stalk fortified with various percentage of the Acacia mangium bark combined with various pelletizing temperatures. The results showed that the moisture content, density, volatile matter, ash content, durabillity, and calorific value of the resulting biopellet were of 0.81-5.37%, 700-840 kg/m3, 70.44-75.85%, 4.62-6.6%, 83.09-92.1% and 3782-4730 Kcal/kg, respectively. The analysis of variance showed that fortification with the bark of acacia did not affect the calorific value of biopellet. The best quality of the sorghum stalk biopellet can be produced with 10% fortification at pelletizing temperature of 150 ºC.
Keyword: Bogor Agricultural University (IPB), pelletizing temperature, biopellet quality, acacia bark, sorghum stalk, biopellet

Judul: Pembuatan biopelet dari campuran biomassa sorgum dan arang tempurung kelapa
Abstrak: Pengembangan energi terbarukan dalam bentuk biopelet dapat diproduksi dari biomassa tanaman dan limbah pertanian. Salah satu tanaman yang cepat tumbuh dalam memproduksi biomassa adalah sorgum, sehingga berpotensi sebagai sumber bahan baku biopelet. Penelitian ini bertujuan untuk menentukan pencampuran arang tempurung kelapa terhadap biomassa sorgum, penambahan perekat tapioka, dan suhu pengempaan. Penentuan kondisi optimum dari ketiga faktor yaitu penambahan arang tempurung kelapa, konsentrasi perekat, dan suhu pengempaan dilakukan dengan menggunakan rancangan Response Surface Methodology (RSM). Variabel respon yang digunakan untuk menentukan kondisi optimum pembuatan biopelet adalah kadar air, zat terbang, kadar abu, karbon terikat, kerapatan, kuat tekan dan nilai kalor. Hasil penelitian menunjukkan bahwa peningkatan jumlah arang akan meningkatkan nilai kalor dan karbon terikat, tetapi menurunkan nilai kuat tekan dan kerapatan biopelet. Kondisi optimum diperoleh pada pencampuran arang tempurung kelapa 25% dari jumlah sorgum, konsentrasi perekat tapioka 0.8%, dan pada suhu pengempaan 180 °C. Karakteristik biopelet yang dihasilkan adalah kadar air 3.06%. Zat terbang 65.25%, kadar abu 11.17%, karbon terikat 23.59%, kerapatan 0.98 g/cm³, Kuat tekan 67.11 kg/cm² dan nilai kalor 4460 kkal/kg…
Keyword: Biopellet, Coconut shell charcoal, Response surface method (RSM), sShorgum biomass, Tapioca, Biomass plant, Agricultural waste, Tapioca adhesive, Temperature compression, RSM, ash, Density, Fixed carbon

Judul: Penentuan Nilai Eigen dan Vektor Eigen dari Matriks Tridiagonal 2-Toeplitz dengan Pendekatan Polinomial Chebyshev
Abstrak: The eigenvalues and eigenvectors of a matrix can be determined by finding its characteristic polynomials. The characteristic polynomials of a tridiagonal 2-Toeplitz matrix is shown to be closely connected to polynomials which satisfy the Chebyshev recurrence relationship. If the order of the matrix is odd, then the eigenvalues are found explicitly in terms of the Chebyshev zeros and the eigenvectors are found in terms of the polynomials satisfying the recurrence relationship. For even ordered matrices, the situation is more complicated. The problem in these cases is that although the Chebyshev recurrence formula is still applied, its initial values are not generating Chebyshev polynomials
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