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: 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: Persamaan Geodesik Black Hole dengan Metrik Kerr 4+1 Dimensi dalam Koordinat Waktu Kosmik
Abstrak: Persamaan geodesik black hole dengan metrik Kerr 4+1 dimensi dalam koordinat waktu kosmik merupakan interpretasi lain dari persamaan geodesik black hole dengan metrik Kerr 4+1 dimensi, dimana acuan waktu yang digunakan diubah dari koordinat waktu wajar (proper time) ke dalam koordinat waktu kosmik (cosmic time). Waktu kosmik merupakan koordinat waktu yang dimana pengamat bergerak mengikuti ekspansi dari alam semesta. Penelitian ini merekonstruksi persamaan geodesik black hole dengan metrik Kerr 4+1 dimensi yang telah ditemukan pada penelitian sebelumnya menjadi persamaan geodesik yang memiliki fungsi terhadap dimensi waktu (t). Hasil akhir dari transformasi persamaan dapat digunakan sebagai bahan studi pustaka untuk penelitian lebih lanjut mengenai persamaan geodesik black hole dalam koordinat waktu kosmik.
Keyword: Dimensi ekstra, Metrik Kerr, Persamaan geodesik, Waktu kosmik