Judul: Biodesulfurisasi batubara Bukit Asam menggunakan Thiobacillus ferrooxidans
Abstrak: Coal is a very important non-renewable energy resource in Indonesia and many industries depend on this resource. In coal burning process, coal produces hazardous waste contains high sulfuric compound that harmful for environment as well as human. In order to reduce sulfur content in the coal, several methods could be applied. One of them is biodesulfurization of coal using T. ferrooxidans. Main objectives of this research are: 1) to know the most effective strain of T. ferrooxidans in order to reduce sulfur content in coal, and 2) to know ability of T. ferrooxidans in order to reduce sulfur content in a bioreactor. The experiments consisted of three main steps, that are: 1) Stock culture rejuvenation, 2) Strain selection, and 3) Coal desulfurization in a bioreactor. Medium that used in this research is according to Leathen et al. (1956). The result of this research show that T. ferrooxidans ICBB 9100 is the most effective strain for coal desulfurization. T. ferrooxidans strain ICBB 9100 can reduce sulfur content 77.53% within 12 days. By treatment of the coal in bioreactor, sulfur content was reduced 62.89% within 2 days by T. ferrooxidans strain ICBB 9100. Key words: coal, biodesulfurization, T. ferrooxidans
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Judul: Kajian Bioreaktor Untuk Pengolahan limbah Air Asam Tambang Dengan Menggunakan Bakteri Pereduksi Sulfat
Abstrak: Coal mining industry is one of the industries which has potency to produce acid mine drainage. Sulfide compound exposed with air will oxidized which produce sulphate compounds. If it react with water, it will generate acid mine drainage containing sulphate. Natural acid can trigger the form of reactive metals on his ion form, thereby will generate contamination of metal at water environment. To reduce contamination of acid mine drainage effect an appropriate technology is required. Biotechnology is an alternative method to threat acid mine drainage, in which a microbe is used as agent for sulphate reduction. The main objectives of this research are: 1) studying bioreactor ability using D. orientis ICBB 1220 to reduce sulphate and dissolved metal of acid mine drainage at various time of biofilm formation; 2) studying bioreactor ability using D. orientis ICBB 1220 to reduce sulphate and dissolved metal of acid mine drainage at vaious time of waste retention time; 3) determine the optimum biofilm formation time and retention time in the bioreactor using D. orientis ICBB 1220 to reduce sulphate and dissolved metal of acid mine drainage. This research has done in a bench scale in the laboratory of environmental biotechnology at Indonesian Center for Biodiversity and Biotechnology (ICBB) Bogor. This research was camed out from October 2006 until October 2007. Research results shown that 5 hours of retention time at 14 days of biofilm formation could be considered as an optimum condition to improve pH from 2.85 to 6.98 and for sulphate reduction from 721.75 to 226.679 (68.59%) and each dissolved Fe and Mn reduction 10.82 to 0.17 (98.43%) and from 13.79 to 3.65 (73.52%).
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Judul: Formulasi Algoritme Operasi Grup Jacobian Kurva Hyperelliptic ...
Abstrak: Dalam geometri aljabar, kurva hyperelliptic merupakan bentuk umum dari kurva elliptic. Kurva ini apabila dikenakan pada suatu lapangan berhingga akan membentuk suatu grup siklik. Pada kriptografi, khususnya enkripsi kunci publik, grup siklik yang dibangkitkan oleh kurva elliptic sudah banyak diteliti. Bahkan untuk kurva ini sudah memiliki standar oleh National Institute of Standard and Technology (NIST) Amerika. Sedangkan, untuk grup yang dibangkitkan oleh kurva hyperelliptic masih memiliki kekurangan dalam hal komputasinya. Tujuan dari penelitian ini adalah mengkonstruksi suatu lapangan berhingga pada , memilih kurva hyperelliptic atas lapangan hingga yang memenuhi kriteria keamanan untuk kriptografi, dan membuat formulasi operasi grup kurva hyperelliptic menggunakan algoritme Cantor. Dalam merekonstruksi lapangan hingga, terlebih dahulu tentukan dimensi dari lapangan hingga tersebut dan polinomial tak-teruraikan. Kemudian dipilih kurva hyperelliptic atas lapangan tersebut. Pada penelitian ini, kurva yang dipilih adalah = + + dengan lapangan hingga . Berdasarkan kurva yang dipilih, akan dibentuk suatu operasi grup dengan menggunakan algoritme Cantor, sehingga menjadi lebih aritmatik. Eksplorasi kurva hiperelliptic dilakukan untuk mengetahui keamanan dari kurva yang dipilih. Dengan menyusun algoritme operasi grup dari kurva yang dipilih, diperoleh perhitungan yang lebih aritmatik dan dapat diimplementasikan pada kriptografi kunci publik. Dari segi keamanan kurva telah memenuhi standar sehingga tahan terhadap serangan-serangan seperti Poligh-Hellman, Polard- , ataupun Frey-Ruck secara teorema.
Keyword: algoritme Cantor, kriptografi, kunci publik, kurva hyperelliptic, operasi grup