Judul: Perbedaan Karakteristik Tanah pada Lahan Reklamasi PascaTambang dengan Tanah Asli tanpa Top Soil (Studi Kasus di PT.INCO Sorowako, Sulawesi Selatan)
Abstrak: Generally, nickel mining was conducted by open pit mining method. This method caused the change of soil physical, chemical and biological properties. For instance, those change are lost of nutrient and organic matter, soil compaction, pollution, change of soil layer, erotion, sedimentation, and the population decrease of soil microorganism. The effect of the top soil lost is the plant cannot grow normally, so that soil is not productive. Therefore, the research was aimed to know the soil characteristic differences (soil physical, chemical and biological) between reclaimed post mining land and natural soil without top soil. That are survey method is used to taking soil sampling for chemical and biological randomly and composite. Soil sampling for chemical properties was taken from 0-10 cm, 10-20 cm, 20-30 cm, 30-40 cm, 40-50 cm and 50-60 cm depth, and soil sampling for biological properties was taken in 0-10 cm depth. However, sampling for soil physic properties was done in certain points of each location used ring sample in 0-30 cm and 30-60 cm depth. Soil sampling for physical, chemical and biological properties was conducted in post mining PT. INCO Sorowako area, South Sulawesi. This soil sample was taken in 2 locations, which are Reclaimed Post Mining (Harapan) and location not yet mined but the top soil was disected until ±1 meter depth (Shelly). The results of this study showed that based on physical and biological properties of soil in Shelly was better than Harapan. Based on physical properties in Shelly of 0-30 cm depth. The bulk density in Shelly was lower and porosity was higher than in Harapan. Biological properties of 0-10 cm depth showed the total fungi, total of soil microorganism, respiration of soil microorganism and C- mic of Shelly was higher than Harapan. The chemical properties of 0-10 cm depth (C-organic, N-total and CEC) in Harapan was very low, on the other hand in Shelly low. Harapan and Shelly had low P-available and Na-dd, very low Ca-dd, high Mg-dd and very high micro nutrient content except enough for Zn, K-dd content in Harapan medium and Shelly was low. Harapan had very high BS with pH 6.7, and BS in Shelly had high with pH 5.8.
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Judul: Perubahan Karakteristik Kimia Tanah pada Model Reklamasi Lahan Bekas Tambang PT. Antam UBPE Pongkor
Abstrak: High mining activity in the forested land had damaged the forest, that reclamation is necessary to restore the forest conditions as before. This research aims at finding out changes on soil chemistry, and the concentration of Pb and Fe in the soil, and the 10 years old planted rosewood, pine, and walnut trees at the reclamation ex-gold mining land as a model of PT. Antam UBPE Pongkor. Soil analysis at 0–5 cm, 5–15 cm and 15–30 cm depth showed increase soil quality, especially in C-organic content at 0–5 cm, which is much higher than the deeper depth. C-organic content of rosewood stand was 2.08%, pine was 1.04% and walnut was 0.95%. The 10 years old planted trees had absorbed Pb and Fe, of which the highest Pb content was found in walnut roots at 13 ppm, while the highest Fe content was in pine roots at 4933 ppm
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Judul: Formulasi Algoritme Operasi Grup Jacobian Kurva Hyperelliptic ...
Abstrak: Dalam geometri aljabar, kurva hyperelliptic merupakan bentuk umum dari kurva elliptic. Kurva ini apabila dikenakan pada suatu lapangan berhingga akan membentuk suatu grup siklik. Pada kriptografi, khususnya enkripsi kunci publik, grup siklik yang dibangkitkan oleh kurva elliptic sudah banyak diteliti. Bahkan untuk kurva ini sudah memiliki standar oleh National Institute of Standard and Technology (NIST) Amerika. Sedangkan, untuk grup yang dibangkitkan oleh kurva hyperelliptic masih memiliki kekurangan dalam hal komputasinya. Tujuan dari penelitian ini adalah mengkonstruksi suatu lapangan berhingga pada , memilih kurva hyperelliptic atas lapangan hingga yang memenuhi kriteria keamanan untuk kriptografi, dan membuat formulasi operasi grup kurva hyperelliptic menggunakan algoritme Cantor. Dalam merekonstruksi lapangan hingga, terlebih dahulu tentukan dimensi dari lapangan hingga tersebut dan polinomial tak-teruraikan. Kemudian dipilih kurva hyperelliptic atas lapangan tersebut. Pada penelitian ini, kurva yang dipilih adalah = + + dengan lapangan hingga . Berdasarkan kurva yang dipilih, akan dibentuk suatu operasi grup dengan menggunakan algoritme Cantor, sehingga menjadi lebih aritmatik. Eksplorasi kurva hiperelliptic dilakukan untuk mengetahui keamanan dari kurva yang dipilih. Dengan menyusun algoritme operasi grup dari kurva yang dipilih, diperoleh perhitungan yang lebih aritmatik dan dapat diimplementasikan pada kriptografi kunci publik. Dari segi keamanan kurva telah memenuhi standar sehingga tahan terhadap serangan-serangan seperti Poligh-Hellman, Polard- , ataupun Frey-Ruck secara teorema.
Keyword: algoritme Cantor, kriptografi, kunci publik, kurva hyperelliptic, operasi grup