Judul: Pengaruh Residu Electric Furnace Slag, Dolomit, dan Unsur Mikro terhadap Sifat Kimia Tanah serta Pertumbuhan dan Produksi Padi Sawah Tanaman Kedua pada Tanah Gambut.
Abstrak: Addition of electric furnace slag (EF slag), dolomite, and micro nutrients improved chemical soil properties, increased growth and yield of rice variety IR 64 as first plant. Content of toxic heavy metals in brown rice was lower than maximum limit of heavy metal in brown rice. The objective of this research was to evaluate residual effect EF slag, dolomite, and micro nutrients on chemical properties of soil and growth and yield of rice on peat soil as second plant. This research consisted of soil analysis in laboratory and green house pot experiment. Experimental design used was completely randomized design. The result indicated that residue of EF slag and dolomite significantly increased soil pH and exchangeable Ca and Mg. Residue of EF slag significantly increased available SiO2 and micro nutrients (Fe dan Mn). Growth and yield of rice with residue of EF slag were better than with residue of dolomite. Content of SiO2 in rice straw with residue of EF slag were higher than with residue of dolomite. The content of toxic heavy metals (Pb, Cd, As, and Hg) in brown rice were not so different their content in market brown and were lower than maximum limit of heavy metal in brown rice. Consequently the brown rice is safe to be consumed.
Keyword: peat., electric furnace slag, dolomite

Judul: Pengaruh Residu Electric Furnace Slag, Blast Furnace Slag dan Unsur Mikro terhadap Sifat Kimia Tanah serta Pertumbuhan dan Produksi Padi Sawah Tanaman Kedua pada Tanah Gambut
Abstrak: Steel slag is a by-product formed in the process of steel manufacturing. Electric Furnace Slag (EF slag) and Blast Furnace Slag (BF slag) are two examples which were used in this research. Steel slag can be used as soil ameliorant. As soil ameliorants, EF slag and BF slag were able to improve chemical properties of peat soil, resulting in enchantment of growth and paddy rice yield of IR 64 on first plant. Toxic heavy metals content was below acceptable limit for rice produced. The objectives of this experiment were to evaluate residual effect of EF slag, BF slag and micro nutrient on chemical soil properties and growth and yield of paddy rice on peat soil as second plant. The results showed that residue of EF slag and BF slag significantly increased soil pH, exchangeable Ca and Mg. Residue of EF Slag and BF slag significantly increased SiO2 and micro nutrients (Fe and Mn). Growth and yield of paddy rice with residue of EF slag were significantly better than those of BF slag. Toxic heavy metals (Pb, Cd, As, dan Hg) in rice were below acceptable limit for rice product. So that rice produced on EF slag and BF slag is save for consumer.
Keyword: Peat, BF slag, EF slag

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