Judul: Biohydrogen Production by Fermentation of Photosynthetic Bacteria Rhodobium marinum and Sanur Isolate.
Abstrak: Bioenergy is renewable energy and prospective to be developed. It is not only can reduce our dependence of fueloil, but also can increase safety of national stock energy. Biohydroen is a type of bioenergy which used as fuel cell, industry necessity, and nuclear. This research have focus on production of hydrogen gas by photofermentation of Rhodobium marinum and bacteria consortium of Sanur isolate using glucose 1% as a substrate. This photofermentation was done with R. marinum and Sanur isolate were centrifuged (6000 rpm, 20 minutes). Then each pellet was resuspented in 75 ml production medium which containing glucose 1% on 100 ml serum bottles and be seted on bioreactor (120 rpm, 30ºC , TL light 60 watts). The result shown that R. marinum ability to used glucose 1% to produce 127.311 ml hydrogen gas of 205.25 gas completly that produced (62%) with production rate is 3.81 mmolH2h-1L-1medium. Bacteria consortium of Sanur isolate also can produce 103.61 ml hydrogen gas of 165.25 ml gas completly that produced (63%) with production rate is 2.8 mmolH2h-1L-1medium.
Keyword: 

Judul: Studi Pemanfaatan Limbah Cair Industri Makanan Lokal untuk Produksi Hidrogen dengan Menggunakan Bakteri Fotosintetik Rhodobium marinum
Abstrak: New, clean and renewable energy systems are required to encounter environmental problems caused by the use of fossil energy sources. Hydrogen is energy carrier that fulfills requirement of clean and environmental friendly energy because hydrogen does not produce greenhouse gases in its combustion. Photosynthetic bacteria are one among other bacteria that can produce hydrogen through photo fermentation process. Liquid waste can be utilized as substrate to produce hydrogen by photosynthetic bacteria. In this study, liquid wastes from local food industries are utilized as organic sources for hydrogen production process because of economical and environmental reasons. Photosynthetic bacteria, Rhodobium marinum, were used as the agent for hydrogen production. Milk, soya sauce and tofu liquid wastes were chosen as organic sources. These liquid wastes were treated by centrifugation, neutralization and sterilization. The wastes also have been characterized and it contains sugar, organic acid and protein. Milk liquid waste directly can produce hydrogen about 141±24 ml after been treated, meanwhile soya sauce liquid waste did not produce hydrogen and had to be diluted. Tofu liquid waste also did not produce hydrogen and could not be continued for optimization because of its small content of nutrients. Milk and soya sauce liquid wastes were examined with dilution (1-80 g/l), addition of iron (0-500 μmol/l for milk liquid waste and 0-160 μmol/l for soya sauce), molybdenum (0-12 μmol/l for milk liquid waste and 0-160 μmol/l for soya sauce) and sodium bicarbonate (0-6 g/l) for optimization purposes. The dilution of milk liquid waste that gives 7.58 g/l total sugar concentration had the highest efficiency with 3.22% mol hydrogen/mol hydrogen theoretical and 10.9 g/l for soya sauce with 6.88% mol hydrogen/mol hydrogen theoretical. From these experiments, the addition of iron, molybdenum and sodium bicarbonate does not affect hydrogen production from milk and soya sauce liquid wastes. For kinetics parameters, milk and soya sauce liquid waste which were treated by pretreatment and without addition of iron, molybdenum, sodium bicarbonate, yeast extract and trace element in SL-6 solution were used as hydrogen production medium with 900 ml working volume. From the experiments, the maximum specific growth for R. marinum in milk liquid waste was obtained to be 0.137 hours-1; Yx/s value was 0.45 g biomass/g substrate, Yp/s value was 0.017 g hydrogen/g substrate and Yp/x value was 0.031 g hydrogen/g biomass. The maximum specific growth for R. marinum in soya sauce liquid waste was obtained to be 0.245 hours-1; Yx/s value was 0.475 g biomass/g substrate, Yp/s value was 0.041 g hydrogen/g substrate and Yp/x value was 0.086 g hydrogen/g biomass.
Keyword: 

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
Keyword: