Judul: Degradation of Petroleum Hydrocarbon on Petroleum – Polluted Soil by A10 and D8 Isolates.
Abstrak: Petroleum pollution could come from spilled oil during drilling, production, refining, and transportation activities. One way to overcome petroleum pollution is by bioremediation method. Bioremediation is a natural environment recovery that utilize microorganism activity to degrade hazardous organic compounds to other compounds like carbondioxide, water, biomass, and side products that are simpler than the original compounds. This research used exogenous bacteria isolates of A10 and D8 as subjects of the process. These isolates applied on 5% (w/w) crude oil contaminated soil. Crude oil hydrocarbon residue was measured using gravimetric method. During five weeks, D8 isolate was able to decrease crude oil contaminant up to 92.30% and A10 isolate up to 60.23%. The gas chromatography-mass spectrophotometry analysis showed that A10 and D8 isolates degraded crude oil by changing the oil compounds become shorter chains.
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Judul: Change of hydrocarbon Compounds During Bioremediation Processes of Soils Polluted by Crude Oil Using Gas Chromatography Mass Spectrophotometry.
Abstrak: Pollution handling that caused by crude oil contamination can use crude oil degrading microorganism. In this reseach change of hydrocarbon compounds degraded by bacteria were investigated with gas chromatography mass spectrophotometry (GCMS). The soils mixed with 5 % (b/b) crude oil was added with T2M bacteria isolated. The change of hydrocarbon compounds and total petroleum hydrocarbon (TPH) were measured every two weeks. TPH mesurement worked by gravimetry method with n-hexane solvent. Preparation for GCMS worked by soxhlet extraction. Extraction finished for 4 hours with 300 ml aseton:n-hexane (1:1) solvent. The extract dried by rotaryevaporator and measured with GCMS. The result of this reseach show that the biggest TPH decrease happened in nonsterilized soils and added bacteria with finally TPH 0.28 % and 93.3 % degradation. Soils were not added by bacteria had finally TPH 0.37 % and 90.17 % degradation. The soils were sterilized and added by bacteria had finally TPH 0.37 % and 90.17 % degradation, even the soils were sterilized and were not added by bacteria had finally TPH 1.37 % and 74.54 % degradation. The change hydrocarbon compounds during degradation process happened to long chain hydrocarbon became shorter hydrocarbon chain. This is showed by the decrease of percent area on chromathograme. The soils were not sterilized and added by bacteria showed the biggest changing because long chain hydrocarbon at the finally measurement were not detected.
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Judul: Closed Knight’s Tour pada Papan Catur Berbentuk Persegi Panjang dengan Ukuran Maksimal 8 × 8
Abstrak: Closed Knight’s Tour merupakan langkah kuda yang mengunjungi setiap kotak pada papan catur tepat satu kali dengan langkah kuda berawal dan berakhir pada kotak yang sama. Graf yang terbentuk dari closed knight’s tour dinotasikan sebagai graf G(m,n), dengan m adalah banyaknya baris dan n adalah banyaknya kolom. Graf tersebut memuat Hamiltonian cycle. Sebuah graf terhubung G adalah graf bipartite jika dan hanya jika graf tersebut tidak memiliki cycle dengan panjang ganjil. Papan catur yang memenuhi syarat cukup untuk memiliki closed knight’s tour adalah papan catur berukuran 5 × 6, 5 × 8, 6 × 6, 6 × 7, 6 × 8, 7 × 8, dan 8 × 8.
Keyword: bipartite, closed knight’s tour, hamiltonian cycle, knight’s tour, teori graf