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: Pemanfaatan Limbah Biomassa Bagasse Sorgum Menjadi Bahan Bakar Biopelet sebagai Sumber Energi Terbarukan.
Abstrak: Limbah biomassa bagasse sorgum yang telah diekstraksi niranya dapat diolah menjadi bioenergi berupa biopelet sebagai sumber energi alternatif. Penelitian ini bertujuan untuk membuat biopelet yang berasal dari biomassa baggase sorgum dengan perlakuan umur tanaman, proses ekstraksi, dan suhu pengempaan. Tahapan penelitian ini meliputi pengambilan bahan sampel dilahan, ekstraksi nira, karaterisasi bahan baku, pembuatan biopelet, dan pengujian karakteristik biopelet. Pengujian karakterisasi biopelet didasarkan pada parameter kadar air, kadar abu, kadar zat terbang, kadar karbon terikat, kerapatan, dan nilai kalor sesuai dengan persyaratan SNI 8021-2014. Pengolahan data penelitian ini dilakukan dengan menggunakan Rancangan Acak Lengkap (RAL) Faktorial dengan 3 faktor, yaitu umur tanaman (70 dan 90 hari), perlakuan ekstraksi/non ekstraksi nira, dan suhu pengempaan (180 dan 220oC). Hasil penelitian memperoleh bahwa: kadar air berkisar antara 2.15-3.82%, kadar abu 5.80-7.35%, kadar zat terbang sebesar 55.45- 67.77%, kadar karbon terikat 25.63-37.52%, kerapatan 0.80-0.99 g/cm3, dan nilai kalor sebesar 4036-4347 kkal/kg. Hasil penelitian menunjukkan bahwa perlakuan umur tanaman 70 dan 90 hari tidak berbeda nyata, namun proses ekstraksi dan suhu pengempaan berpengaruh terhadap kualitas biopelet. Nilai kalor terbaik yang diperoleh pada biopelet berumur 90 hari dengan ekstraksi dan suhu pengempaan 220oC yakni sebesar 4347 kkal/kg.
Keyword: Biomassa, biopelet, nilai kalor, sorgum

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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