Judul: Kemampuan Konsorsium Mikrob dari Kotoran Sapi dan Kuda pada Proses Biodegradasi Limbah Minyak Berat
Abstrak: Heavy oil waste (HOW) which is produced by petroleum industry has become environment problem until now. Bioremediation is a method that can recover the polluted environment. This research was carried out to evaluate microbe consortium from cow and horse manure in biodegradation of heavy oil waste with adjustment of total petroleum hydrocarbon (TPH) 5% (w/v) and 10% (w/v). The observed parameters were solid TPH, liquid TPH, total plate count, chemical oxygen demand, and pH. The highest percent degradation was obtained from 5% TPH. Microbes were easier in degrading 5% TPH than that of 10% TPH. This is because the low toxicity of TPH 5%. TPH degradation at the 21st day reached 40.36% with addition of horse manure consortium enriched by 5% TPH, while with cow manure consortium was only reached 22.77%. TPH degradation at the 21st day was reached with addition of horse manure consortium enriched by 10% TPH, while with cow manure consortium was reached 16.80% of TPH degradation. It also showed that microbes in consortium of cow’s manure were better on degrading HOW than microbes in horse manure consortium.
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Judul: Profil Kelarutan Limbah Minyak Berat Akibat Penambahan Bahan Pencampur
Abstrak: Heavy oil waste (HOW) is one petroleum waste in a form of black viscous liquid. Bioremediation is an alternative technology which is friendly, effective, efficient, and economic. However, HOW's solubility in water is in fact very low that we to mixed it with another materials to increase its solubility. The materials used in the mixture were sodium tripolyphosphate (STPP), carboxymethyl celullose (CMC), quartz sand, and pumice stone. The ratio of HOW STPP was 11:1, HOW:CMC was 22:1, HOW:quartz sand was 8:1, and HOW:pumice stone was 5:1. Primary characteristics of HOW were 17.22% solid TPH, 1.96% average moisture content 1.96%, and metal content in HOW were 1.4942 ppm of eu and 3.3300 ppb ofHg. All four of the mixing agent have showed dispersion property that can be shown by several parameters such as turbidity, solid TPH, liquid TPH, pH, and chemical oxygen demand (COD). The highest turbidity was 451.5 NTU for mixed HOW and STPP. While the lowest solid TPH was 13.49% for mixed HOW and pumice stone. The highest liquid TPH value was shown by mixture of HOW and STPP with 0.26%. Range of pH value revealed in the experiment was around between 3.6 until 7.9. The highest COD value of was shown by mixture of HOW and STPP with 7592 mglL. STPP was the best mixing agent.
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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