Judul: Delignifikasi Biomassa Limbah Sorgum melalui Teknik Mikrogelembung Oksigen dan Ozon
Abstrak: Sorgum manis (Sorghum bicolor (L.) Moench) merupakan salah satu tanaman serealia yang berpotensi untuk dikembangkan di Indonesia. Kandungan selulosa sorgum yang tinggi dapat mencapai 44% tetapi belum banyak dimanfaatkan. Delignifikasi menggunakan ozon merupakan salah satu teknologi prospektif yang ramah lingkungan dan mengurangi biaya operasional. Penelitian ini bertujuan menentukan selektivitas delignifikasi (nisbah selulosa/lignin) dan menetapkan kondisi terbaik pada proses ozonolisis sorgum serta mencirikan karakteristik serat hasil delignifikasi sebagai bahan baku pembuatan pulp. Delignifikasi dilakukan dengan menggunakan ragam pH 3, 7, dan 10. Ozon dialirkan ke dalam reaktor dengan laju alir 3 L menit-1 selama 30, 45, dan 60 menit. Proses ozonolisis memberikan nilai selektivitas delignifikasi tertinggi pada pH 3. Nilai turunan dimensi serat menempatkan biomassa sorgum manis termasuk kelas kualitas serat II sehingga berpotensi sebagai alternatif bahan baku dalam pembuatan pulp., Sweet sorghum (Sorghum bicolor (L.) Moench) is one of the cereal crops that has the potential to be developed in Indonesia. The high cellulose content of sorghum can reach 44% but has yet to be widely utilized. Delignification using ozone is an environmentally friendly technology that reduces operational costs. This study aims to determine the delignification selectivity (cellulose/lignin ratio), determine the best conditions for the sorghum ozonolysis process, and characterize the delignified fiber as a raw material for pulping. Delignification was performed using a pH range of 3, 7, and 10. Ozone flowed into the reactor at a flow rate of 3 L min-1 for 30, 45, and 60 minutes. The ozonolysis process provides the highest delignification selectivity value at pH 3. The derived value of fiber dimensions places the sweet sorghum biomass into fiber quality class II, potentially an alternative raw material in pulp production.
Keyword: delignification, lignocellulosic, ozonolysis, Sorghum bicolor

Judul: Pembuatan bioetanol dari bagas batang sorgum manis melalui proses delignifikasi oleh NaOH
Abstrak: Sweet sorghum bagasse rod including lignocellulosic materials containing lignin, cellulose and hemicellulose that can be used in the manufacture of ethanol. This study aims to stem the production of ethanol from sweet sorghum bagasse. Stages of research consists of preparation of sweet sorghum bagasse rod, pretreatment using NaOCl, delignification with NaOH, saccharification with xylanase and cellulase enzymes and fermentation by Saccharomyces cerevisiae. The parameters in the analysis include the levels of lignin, cellulose and hemicellulose before and after delignification, reduction sugar and ethanol. The results showed that sweet sorghum bagasse rod can be used as raw material in the manufacture of bioethanol, because it is based on data obtained cellulose content before delignification at 23.45% while after delignification, cellulose optimum levels obtained with 8% NaOH concentration is 18.38%. Highest glucose levels obtained from the saccharification at a concentration of 1% cellulase and xylanase 1% at 177%. Highest levels of ethanol during fermentation by S. cerevisiae with a concentration of 2% inoculum were incubated for 6 days is 19.34 %
Keyword: Bogor Agricultural University, Saccharomyces cerevisiae, saccharification, fermentation, ethanol, delignification, cellulose, Bioethanol

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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