Judul: Pengaruh Electric Furnace Slag, Silica gel dan Unsur Mikro terhadap Sifat Kimia Tanah Serta Pertumbuhan dan Produksi Tanaman Padi Sawah (Oryza sativa L.) pada Tanah Gambut dari Kumpeh, Jambi
Abstrak: The staple food of Indonesian is rice, concequently paddy is the most important crop in agriculture. Peat soil is one of marginal land which potential to create the availability of land for paddy in Indonesia. Generally, peat soil in Indonesia has low fertility and availability of silicon (Si). Silicon is beneficial element for paddy rice. Recently, general material used as sources of Si in some countries is steel slag of which consist calcium silicate. One kind of steel slag produced in Indonesia is electric furnace slag. However, according to regulation of government (PP No. 18, 1999 and No. 85, 1999), steel slag is categoried at hazardous waste. The objectives of this research were to determine the effect of EF slag, silica gel, and micro elements on chemical properties of soil, growth and yield of paddy rice on peat soil and to evaluate content of heavy metal in rice for worthiness of rice consumption. This research used peat soil from Kumpeh Regency, Jambi. The research consisted of two experiments, they were incubation experiment in laboratory and pot experiment in greenhouse. The dosage applied for treatment of EF slag and silica gel were 0%, 2%, 4%, 6%, and 8%. Application of EF slag significantly increased pH, exchangeable Ca and Mg, available-Fe, Mn, Zn, SiO2, and P. Growth and yield of paddy rice with EF slag was better than with silica gel and micro nutrients. Furthermore, the content of heavy metal in rice was very low, so that the rice produced is not harmful and can be consumed.
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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: Invers dari Matriks Tridiagonal Jacobi
Abstrak: Suatu matriks berukuran n×n dinamakan matriks tridiagonal jika untuk . Karya ilmiah ini memberikan algoritma yang mudah untuk menemukan invers ( dari matriks tridiagonal Jacobi yang simetrik dan nonsimetrik. Setiap elemen pada matriks tridiagonal ini adalah bilangan real. Terdapat 3 lema dan 2 teorema untuk menentukan . Lema pertama menunjukkan persamaan utama dalam membuktikan lema-lema dan teorema-teorema selanjutnya. Invers dari matriks yang simetrik dibuktikan oleh lema kedua yang menunjukkan elemen-elemen baris ke- dari . Selanjutnya, lema kedua dilengkapi dengan teorema pertama yang menunjukkan elemen-elemen dengan . Invers dari matriks yang nonsimetrik dibuktikan oleh lema ketiga yang menunjukkan elemen-elemen dengan dan elemen-elemen dengan dibuktikankan oleh teorema kedua.
Keyword: symmetric, nonsymmetric, matrix