Judul: Unsur-unsur yang dibebaskan dari proses pencucian abu terbang (fly ash) dari PLTU Suralaya
Abstrak: Coal combustion produce solid waste known as fly ash. A number of fly ash cause serious problem almost in every coal power plant. However fly ash consist of potential nutrient that could be used in agriculture. This research studied the chemical characteristics of fly ash and the nutrients released under leaching during 3 months. Three kind of fly ash are used fresh, 6 months deposited fly ash out-door, and 5 years out-door deported fly ash. The analyses conducted were pH, EC (Electrical Conductivity), macro elements (K, Na, Ca, Mg), micro elements (Fe, Mn, Zn, Cu), and metals (Cr, Ni). The result showed that the three fly ash samples in this research were alkali. The pH value of fresh fly ash is 11,1. The six months fly ash was 9,4 in pH value and five years fly ash was 8.4 in pH value. Electrical conductivity of fresh fly ash was 3,12 dSm-1. It was higher than electrical conductivity of landfiil’s fly ash. Electrical conductivity of six months fly ash and five years fly ash were0,76dSm-1 and 0,39 dSm-1. According to this research, fresh fly ash also contained more elements than landfiil’s fly ash. This research also used percolation method. Result of percolation method show that pH value of percolate were between 7,3 to 7,8. Percolate pH value of fresh fly ash was higher than percolate pH value landfiil’s fly ash. Percolate electrical conductivity were between 0,20 dSm-1 to 0,35 dSm-1. Percolation method also showed that percolate contained variety number of macro elements (K, Na, Ca, Mg). This percolate also has small number of micro elements (Fe, Mn, Zn, Cu) and metals (Cr, Ni). Percolate elements in the first month was higher than it were in the third month.
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Judul: Sifat-sifat kimia tanah di sekitar landfill abu terbang (fly ash) pltu suralaya
Abstrak: Increased utilization of energy causes a need to produce alternative energy, for example coal. Coal combustion produces fly ash that contains of major and trace elements such as Ca, Mg, K, Na, P, Fe, Cu, Zn, Mn and also has advantage as soil ameliorant. The purpose of this research was to study the soil chemical characteristics that might impacted by fly ash accumulation at PLTU Suralaya. The 13 samples of soil has been taken close to (± 10 meters) and outside (± 1 kilometers) the landfill. The soil analyzes consisted of pH, Cation Exchangable Capacity (CEC), C-organic, base elements and base saturation, total and avalaible P, total N, Electric Conductivity (EC), texture, trace elements, and heavy metals. Generally, the characteristics of soil were had little differences. The value of pH in close to landfill soil (5,41-5,64) was higher than in outside (5,29-5,77), as same as the EC value in close to landfill (0,033-0,49 dS/m) was higher than the outside (0,016-0,048 dS/m). The concentration of base elements in close to landfill soil (Ca = 6,87-8,48 cmol/kg, Mg = 2,89-3,96 cmol/kg, K = 0,47-0,71 cmol/kg, Na = 0,39-0,47 cmol/kg) were higher than the outside (Ca = 5,85-8,56 cmol/kg, Mg = 2,30-2,81 cmol/kg, K = 0,17-1,43 cmol/kg, Na = 0,29-0,60 cmol/kg), it’s equal with the CEC value in close to landfill soil (15,14-18,04 cmol/kg) that was higher too than the outside (10,95-15,14 cmol/kg). The C-organic value (1,83-2,41%) and the avalaible of P (13,03-28,94 ppm) in close to landfill soil were higher than C-organic (0,88-1,85%) and avalaible of P value (13,65-19,26 ppm) in the outside. Whereas, the base saturation (67,53-82,01%) and total phospore (27,33-38,33 ppm) in close to landfill soil were lower than the outside base saturation (70,43-97,06%) and total phospor (30-43,67 ppm). The total N at two locations were similar. Trace elements within the close to landfill (Fe = 5,37-6,28%, Mn = 0,20-0,24%, Cu = 7,30-8,60 ppm) were lower than the outside (Fe = 6,09-7,72%, Mn = 0,15-0,27%, Cu = 7-9 ppm). But, the Zn element (36-38,5 ppm) was higher in close to than in the outside landfill (18,6-32,3 ppm). The existing of heavy metals in close to landfill (Cr = 1-1,5 ppm, Ni = 0,5-1 ppm) were lower than in the outside (Cr = 1-2,5 ppm, Ni = 1-3 ppm), the texture were same, clay.
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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