Judul: Delignifikasi limbah tanaman jagung menggunakan kalsium hidroksida
Abstrak: Sejak tahun 90-an, lignoselulosa mulai gencar untuk dijadikan sumber energi oleh para peneliti dunia. Di Indonesia, sebenarnya potensi untuk pengembangan bahan ini cukup baik jika ditinjau dari kebutuhan energi. Di samping itu, ketersediaan bahan tersebut cukup melimpah, salah satunya adalah LTJ (limbah tanaman jagung) yang jumlahnya diperkirakan 18.9x1013 ton/tahun. Meskipun lignoselulosa cukup melimpah, pemanfaatannya memerlukan perlakukan khusus karena strukturnya yang kompleks antara selulosa, hemiselulosa, dan lignin. Berbagai perlakukan telah dikembangkan, baik secara fisik, biologi, maupun kimia. Salah satu perlakuan adalah delignifikasi dengan Ca(OH)2 untuk meminimalkan kerusakan selulosa dan hemiselulosa. Penelitian ini bertujuan untuk mengetahui pengaruh penambahan Ca(OH)2, penambahan air, temperatur pemanasan, dan lama pemanasan pada delignifikasi. serta mencari kondisi terbaik pada proses delignifikasi limbah tanaman jagung dengan Ca(OH)2. Hasil percobaan menunjukkan bahwa hanya perlakuan temperatur yang memiliki pengaruh nyata terhadap proses delignifikasi, sedangkan penambahan Ca(OH)2, penambahan air, dan lama pemanasan tidak berpengaruh nyata terhadap proses delignifikasi. Pada rentang yang diuji telah terdeteksi adanya kurvatur, dan diperoleh persamaan : LR * = − 0.24197 + 0.007951 x3 – 5.3∙10-5 x3 2. Kondisi terbaik proses ini diperkirakan ada pada suhu 74.6 oC, dengan susut lignin sebesar 0.055 g/g LTJ, tingkat delignifikasi 0.25, dan tingkat selektivitas delignifikasi 0.40.
Keyword: Lime delignification, Corn stover, Delignification selectivity, Bogor Agricultural University, Institut Pertanian Bogor, IPB

Judul: Delignifikasi Limbah Tanaman Jagung Menggunakan Kalsium Hidroksida.
Abstrak: Since the 90’s, lignocelluloses began aggressively to become a source of energy by researcher of the world. In Indonesia, the actual potential for the development of this material is quite good if viewed from its energy needs. In addition, the supply for this material is relatively abundant, one of which is corn stover. The production of corn stover is about 18.9x1013 ton/year. Although, lignocellulose is relatively abundant, its utilization requires special treatment because of the complex structure of celluloses, hemicelluloses, and lignins. Various treatments have been developed included physical, biological, or chemical. One of the treatments is delignification with lime to minimize damage to the celluloses and hemicelluloses. This study aims to determine the effect of lime addition, water addition, heating temperature, and heating time on delignification, and to find the best condition in the delignification process of corn stover with lime. The experimental result shows that significant factor in delignification is heating temperature, whereas lime addition, water addition, and heating time did not have significant influence in delignification. In the tested range also has detected the existence of curvature, and obtained the equation: LR * = − 0.24197 + 0.007951 x3 – 5.3∙10-5 x3 2. The best condition of this process is estimated at 74.6 oC, with lignin removal is 0.055 g/g corn stover, delignification level is 0.25, and delignification selectivity is 0.40.
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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