Judul: Karakterisasi Limbah Abu Batubara (Fly Ash dan Bottom Ash) untuk Pemanfaatan dalam Bidang Pertanian
Abstrak: The use of coal as a fuel would produce solid waste such as fly ash and bottom ash which haven’t been widely used especially in agricultural sector. This is because government regulation No. 85th (1999), coal ash waste classified as hazardous waste. The objective of this research was to study the characteristic of coal ash waste from two different sources, as the basis for the utilization for agricultural sector development. The characteristic test of coal ash waste done through with several chemical analysis namely total chemical analysis, analysis of heavy metals content by TCLP (Toxicity Characteristic Leaching Prosedure) which refers to the USEPA (1992), pH (H20 1:5), and solubility of macro and micro nutrients. The total chemical showed that fly ash and bottom ash contain several nutrients so that it could be used as an amelioran. In addition fly ash and bottom ash also contain Pb, Cd, Cu, Zn, Cr, and Hg. However, TCLP test showed that the heavy metal content of fly ash from PLTU Nagan Raya and PT. Pupuk Kaltim were lower than the standard of TCLP according to USEPA (1992) and government regulation No. 85th (1999). The result of the pH measurement showed that the coal ash from the PLTU Nagan Raya, Aceh was alkaline in that pH value of fly ash and bottom ash were 8.9 and 8.0 respectively. While the pH value of fly ash from PT. Kaltim was 5.1. The results of the solubility test generally showed that the Ca and Mg elements were higher than that of K, Na, Fe and Mn. Moreover, there were other elements including Cu, Zn, Pb and Cd found in low concentration.
Keyword: TCLP test, fly ash, bottom ash

Judul: Karakterisasi abu terbang (Fly ash) dan eksplorasi vegetasi fitoremediator di area Landfill abu terbang untuk pengelolaan ramah lingkungan:
Abstrak: The increasing need of electricity and the decreasing availability of fosil fuel oil has increased coal based power plant development. At present in Indonesia, electricity generated from such power plant is about 30%. Combustion of coal for the generation of electricity produces solid waste such as fly ash in huge amount (7 million tons in 2008/2009). Dumped fly ash in landfill might have negative impact to environmental because fly ash contains toxic metals. In contrast fly ash contains many essensial elements for plant growth. To overcome this problem, many possible beneficial appliations of fly ash are being evaluated to minimize waste. This research was conducted to find out characteristic of fly ash and vegetation which naturally grown on fly ash landfill, and to evalute development prospective of utilization of fly ash and vegetation in the context of environmental management. Two Samples of fly ash were taken from PLTU Suralaya Cilegon Banten, i.e. electrostatic precipitator (ESP) ash and landfill ash. Roots and crowns of plants grown on landfill fly ash i.e. Passiflora foetida, Eupatorium odoratum, Chlorisbarbata, Erigeron sumatrensis and Pithecellobium dulce were sampled. Ashes were analyzed for pH, EC, organic C and element content, while plants only analyzed for metals content. The result showed not all fly ash contains toxic metals in high concentration. Vegetation which naturally grown on landfill area that potentially can be used for fitoextraction were P. foetida and Chlorisbarbata, and for fitostabilization were E. odoratum and P. dulce. According to the characteristic of the fly ash of from many area in the world it has potential to be utilization of fly ash both for agricultural and non agricultural purposes were proposed.
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Judul: Grup dan Homomorfisma Grup pada Rubik Revenge
Abstrak: Rubik cube is a kind of puzzle game. A player must arrange rubik sides, which have been disordered, back to the position where every side has the same colour. This paper does not focus on the settlement solution, but instead on proving the existence of a group homomorphism between rubik movement group and S96 symmetric permutation group in rubik revenge. Firstly, it has been proved that rubik movement set is a group. Then, it also has been proved that the M set, which contains numeric labels of 1 until 96 in cubinos sides, is S96 symmetric permutation group.
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