Judul: Pengaruh Letak Pemberian Pupuk NPK terhadap Pertumbuhan Akar Semai Sengon (Paraserianthes falcataria (L.) Nielsen)
Abstrak: Knowledge about setting of the root characteristic is very necessary to avoid competition between forest plants with cropping on agroforestry system. This research aims to determine the effect of fertilizer to the dimensions, depth of the root and growth of seedling roots of sengon corresponding layout fertilizer as agroforestry system simulation. The results showed that the highest of root depth and dimension was found in the plants that have treatment of direction and perpendicular NPK fertilizer to the line and without fertilizer. The growth of plant roots sengon given fertilizer NPK will evolve following the layout of the fertilizer, it showed that the growth of plants roots sengon planted in agroforestry system better than monocultures.
Keyword: P. falcataria, NPK fertilizer, fertilizer layout, roots, agroforestry

Judul: Aplikasi Pupuk Kandang dan NPK pada Respons Pertumbuhan Sengon (Paraserianthes falcataria (L.) Nielsen) di Media Bekas Tambang Kapur.
Abstrak: Kegiatan pertambangan kapur merupakan eksploitasi sumberdaya alam yang berlebihan, sehingga dapat memberikan dampak negatif terhadap lingkungan. Penanaman jenis sengon (Paraserianthes falcataria) dalam kegiatan revegetasi diharapkan dapat memperbaiki ekosistem yang rusak akibat aktivitas penambangan. Penambahan pupuk kandang dan NPK dapat memperbaiki sifat fisik, kimia dan biologi tanah. Tujuan penelitian ini adalah mengkaji pengaruh pemberian pupuk kandang dan NPK terhadap pertumbuhan sengon (Paraserianthes falcataria) pada media bekas tambang kapur Ciampea serta memperoleh informasi mengenai dosis pemberian pupuk kandang dan NPK yang terbaik dalam pertumbuhan semai sengon. Hasil penelitian ini menunjukkan bahwa pemberian pupuk kandang tunggal dan NPK tunggal tidak berpengaruh nyata pada semua parameter seperti tinggi, diameter, berat basah total, berat kering total, nisbah pucuk akar dan jumlah bintil akar. Pengaruh pada interaksi antara pupuk kandang dan NPK hanya berpengaruh nyata pada parameter jumlah bintil akar, untuk parameter lainnya tidak berpengaruh nyata. Perlakuan P1N10, P1N15 dan P2N0 merupakan perlakuan terbaik pada parameter jumlah bintil akar.
Keyword: NPK, Paraserianthes falcataria, pertambangan kapur, pupuk kandang

Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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