Judul: Karakteristik Tanah Bekas Tambang di Wilayah Pertambangan Cikotok, Kab. Lebak Jawa Barat
Abstrak: Tujuan penelitian ini untuk mempelaj ari karakteristik tanah bekas tambang di Wilayah Eksplorasi Pertambangan Emas-Perak Cikotok Lebak Jawa Barat. Melalui upaya pengklasifikasian jenis tanah alami dan jenis tanah bekas tambang atau tanah timbunan di lokasi tersebut, didapat gambaran umum tanah yang ada. Untuk mencapai tujuan terse but telah diobservasi enam pedon (dua pedon alami dan empat pedon timbunan), kemudian dilakukan deskripsi profil dan pengamatan lingkungan, selia analisis contoh tanah. HasiJ penelitian menunjukkan bahwa pedon PI level 100 Cirotan dan pedon P5 level 300 Cikidang yang mewakili tanah alami, berturut-turut diklasifikasikan sebagai Tipik Hapludult, berliat hal us, campuran, isohiperterrnik dan Tipik Distropept, berlempung hal us, campuran, isohipertermik. Sedangkan pedon P2 level 200 Cirotan, pedon P3 level 600 Cirotan, pedon P4 level 800 Cirotan dan pedon P6 level 300 Cikidang yang mewakili tanah timbunan, berturut-turut diklasifikasikan sebagai Tipik Troporthent, berlempung hal us, campuran, isohipertermik; Tipik Troporthent, berlempung kasar, campuran, isohipertermik; Tipik TropOlihent, berlempung kasar, campuran, isohipertermik; Tipik Troporthent, berlempung kasar, campuran, isohipertermik. Tanah alami di kedua daerah umumnya memiliki sifat fisik yang cukup baik, kecuali di Cikidang solum tanahnya dangka\. Selain itu, tanah di Cikidang dan Cirotan memiliki pH yang rendah. Sementara, sifat fisik mauplill kimia lIntlik tanah timbunan di kedlla daerah umumnya buruk. Sifat fisik yang buruk pada tanah bekas tambang tersebut (seperti: perkembangan horison lemah dan tingginya kandllngan fragmen batuan), umurnnya lebih sulit untuk diperbaiki dibandingkan dengan sifat kimia tanah tersebut (seperti: kemasaman dan kandungan hara yang rendah), karena memperbaiki karakter sifat fisik ini membutuhkan manipulasi mekanik yang sangat mahal. Berdasarkan hasil pengamatan di lapang, ciri khas vegetasi yang bisa tumbuh di lokasi studi terdiri dari; vegetasi hutan lokal, semak belukar dan rerumputan. Sedangkan upaya konservasi lahan pada lereng timbunan, selain dengan penataan timbunan dilakukan pula sistem bronjong, sebagai alat teknik sipil konservasi.
Keyword: 

Judul: Kajian Sifat Fisik, Sifat Kimia dan Sifat Biologi Tanah Paska Tambang Galian C pada Tiga Penutupan Lahan (Studi Kasus Pertambangan Pasir (Galian C) di Desa Gumulung Tonggoh, Kecamatan Astanajapura, Kabupaten Cirebon, Provinsi Jawa Barat)
Abstrak: Introduction: Indonesia is a country that has abundance natural resources like dig substance, mineral, petroleum, gas, flora and fauna residing in the land. Sand is one of dig substance which is quite abundant on this country. This dig substance is usually exploited by open mining. Open mining has benefits for building materials, local’s occupations and increasing the local income. However, Open mining has negative impacts for wildlife, land cover loss, and land quality degradation. Because of these negative impacts, it needs to conduct a research about the effect of sand mining toward physical, chemistry, and biology soil characteristics. Methodology: Research was conducted on sands open mining at Gumulung Tonggoh village, Astanajapura district, Cirebon regency, West Java province. Instrument that used for this research are hoe, plastic poke, camera, calculator, SPSS 13.0 software. The data are primary data for land structure and secondary data for soil’s physical, chemistry, and biology characteristic. The method of this research was survey with purposive sampling which has done by ministry of state environment year 2006 and statistical data on site. Then conducted some statistical F test on soil characteristic to know whether there is significant or not from sand mining activity and after continued by Duncan’s test, locations that has significant difference can be showed. Result and Discussion: Sand Mining activities have altered soil’s physical, chemical, biology characteristics on after-mining sites in Gumulung Tonggoh village. It has been proved by significant change of bulk density value, low porosity, and rapid decrease of drainage pore. Soil’s chemical characteristic has significant change as well. There is some soil characteristic that is influenced by mining activities like change cation capability (KTK), calcium and magnesium decreasing and the increasing of phosphor inside the soil. For soil biology characteristic, only amount of soil’s microorganism that influenced by sand mining activities. It has been analyzed by significant value and have significant value < 0,05 actual rate as a result. Permeability, pH, BO, nitrogen, kalium, natrium, amount of soil’s fungi, phosphate-dissolved bacteria and soil respiration have change but not really significant as a results of statistic test. The changes of soil characteristic on this research happens because soil’s condensation as a result of using of heavy instruments. Conclusion: Sand Mining activity ( Dig C) in Gumulung Tonggoh village have altered some characteristic changes of soil’s physical, chemical and biology characteristic because of land condensation by heavy equipment use on mining activity. Based on statistical test, character that significant is bulk density value, land porosity, drainage pore very quickly, KTK, phosphor, calcium, magnesium and amount of soil microorganism. Characteristic changes on soil characteristics affect one and each other.
Keyword: 

Judul: Best Difference Equation Aproximation to Duffing 's Equation
Abstrak: Persamaan Duffing merupakan persamaan yang sering muncul sebagai model masalah sistem ayun mekanis atau pada masalah rangkaian listrik. Umumnya penyelesaian persamaan ini secara numerik memberikan hampiran dengan gala! yang tinggi, seperti dengan metode Runge-Kutta. Tulisan ini mengkonstruksi suatu persamaan beda untuk menghampiri persamaan Duffing tersebut. Penyelesaian dari persamaan beda ini melibatkan fungsi-fungsi eliptik Jacobi. Berdasarkan penyelesaian ini diperoleh basil bahwa penyelesaian hampirannya persis sama dengan penyelesaian analitiknya. Penyelesaian analitik yang diperolehjuga melibalkan fungsi-fungsi eliptik Jacobi.
Keyword: