Judul: Pertumbuhan Bibit Sengon (Paraserianthes falcataria (L) Nielsen) pada Media Bekas Tambang Pasir dengan Pemberian Subsoil dan Arang Batok Kelapa
Abstrak: Exploitation of natural resources in order to meet the increasingly commonplace as the needs of the population increase. Exploitation are likely to cause environmental damage. One such activity is the mining of sand. River sand mining will lead to a sustained decrease in the amount of sand in the river bed. As a result, the river will be damaged by excavation continues. In addition to damaging the ecosystem of the river, sand mining has also led to a decrease in water quality and air pollution. In order to reduce the impact of damage, utilization and processing of mining waste as a growing medium in a first step into alternative revegetation can be done. However, low nutrient content and CEC and texture of sand dominated an obstacle in the utilization of tailings sand as a growing medium. Application subsoil and the addition of coconut shell charcoal is expected to help improve these constraints. Sengon is a very fast growing plant and has a high potential and has been widely known to the public. These plants are best used in the post-mining land rehabilitation. The results showed that the addition of the interaction of subsoil and coconut shell charcoal gives the best growth of influence. Interaction addition of 75% subsoil and charcoal 40 g (a3b2) is the best treatment to improve seedling height by 64%. While the increase in diameter increment, the interaction of subsoil 75% and the addition of 60 g charcoal (a3b3) is the best treatment with the addition of a diameter of 87.50%. The best treatment for weight parameters in total bases (BKT) and total dry weight (BKT) indicated by the treatment (a3b3) with a 63.49% increase% and 36.10%. Giving a single charcoal best in show at the addition of 60 g charcoal (a0b3). Indicated by a high addition of 47.32%. While granting subsoil singly not give significant effect on seedling growth.
Keyword: sengon, subsoil, Charcoal, mining sand

Judul: Pertumbuhan Semai Jabon (Anthocephalus cadamba) pada Media Bekas Tambang Pasir dengan Penambahan Sub Soil dan Arang Tempurung Kelapa
Abstrak: The effect of sand mining are environmental degredation and reduction of soil quality (physically, chemistry, or biological). The land of ex-sand mining could be marginal land and causes the revegetation barrier. Soil amendment is a necessary phase for this problem i.e. additional of sub soil and charchoal of coconut shell on the soil. The species selection also determine for revegetation result. Jabon (Anthocephalus cadamba) is an pioneer, adaptive and fast growing species. The aim of this reasearch are to analyze the effect of sub soil and charcoal of coconut shell increment to the growth of jabon seedling on ex-sand mining soil and to find out the optimum dose of sub soil and charcoal of coconut shell increment. The result of this research showed that sub soil and charcoal of coconut shell increment on ex-sand mining soil extend positive influence. The combination 500 g sub soil and 20 g charcoal of coconut shell gave the best growth for jabon seddling on ex-sand mining soil.
Keyword: sub soil, sand mining, coconut shell, charcoal, Anthocephalus cadamba

Judul: Invers Drazin dari Matriks Toeplitz Singular
Abstrak: Matriks Toeplitz adalah matriks yang setiap unsur pada diagonal utama bernilai sama dan setiap unsur pada subdiagonal yang bersesuaian dengan diagonal utama juga bernilai sama. Matriks singular adalah matriks yang tidak bisa ditentukan inversnya. Akan tetapi, dapat diupayakan untuk ditentukan inversnya menggunakan invers matriks yang diperumum. Invers Drazin merupakan salah satu jenis invers matriks yang diperumum. Pada karya ilmiah ini ditentukan invers Drazin dari matriks Toeplitz singular dengan menggunakan metode Leverrier Faddeev. Kemudian, ditentukan invers Drazin dari matriks Toeplitz singular yang direpresentasikan sebagai penjumlahan segitiga bawah dan segitiga atas matriks Toeplitz berdasar pada teorema Gohberg dan Semencul., Toeplitz matrix is a matrix in with element on the main diagonal has the same value and on the subdiagonal corresponding to the main diagonal also has the same value. Singular matrix is a matrix that has no inverse. However, it can be attempted to determine the inverse using a generalized inverse matrix. Inverse Drazin is a type of generalized matrix inverse. This paper discussed the inverse Drazin for a singular Toeplitz matrix using the Leverrier Faddeev method. Then, the Drazin inverse of the singular Toeplitz matrix which is represented as a sum of products of lower and upper triangular Toeplitz matrix based on Gohberg and Semencul theorem.
Keyword: inverse Drazine, singular Toeplitz matrix