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.
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Judul: Produksi biohidrogen oleh bakteri fotosintetik Rhodobium marinum pada pencahayaan berbeda, Biohydrogen Production using Photosynthetic Bacteria Rhodobium marinum by different lighting
Abstrak: Energy demand that increases continuously and various problems are found in using fossil fuels motivates searching reneawable alternative energy. Biohydrogen as a new and renewable energy has a potential in resolving the energy problems. Hydrogen producing microbe is affected by lighting. This study concerns with effective wavelength lighting for hydrogen producing. The aim of this study is to determine effective lighting from UV and visible light (red, yellow, and blue) for maximum biohydrogen production by photosyntetic bacteria Rhodobium marinum. Hydrogen gas from photo fermentation was determined using gas chromatography (GC) with thermal conductivity detector, poropak column, with temperatur of injector, detector, and column were 150, 250, dan 80 ˚C, respectively. Total gas from photo fermentation generated with UV and visible (red, yellow, blue) lighting were 150, 145, 131, dan 95 ml, respectively. GC analysis showed hydrogen content from total gas of UV and visible (red, yellow, blue) lighting are 8.725, 13.565, 5.495, dan 6.905 ml, respectively. Yellow lighting resulted in the highest amount of hydrogen gas among the others. Therefore, the wavelength of yellow lighting is the maximum for R. marinum to produce hydrogen.
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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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