Judul: Pengaruh Populasi Cacing Tanah Eisenia foetida, Pupuk NPK dan Kapur terhadap Produktivitas dan Kualitas Sorgum (Sorghum bicolor L. Moench) Varietas Numbu pada Latosol Dramaga
Abstrak: Eisenia foetida is known as potential earthworm to reorganize the organic matter into inorganic matter that are beneficial to plants. This research aimed to determine the influence of population of earthworm E. foetida, NPK fertilizer and lime to productivity and nutritional quality of sorghum (Sorghum bicolor L. Moench) in Latosol Dramaga. The observed variables were the vertical height of plants, number of leaves, fresh weight, dry matter, crude protein, crude fiber and content of calcium. This research used factorial completely randomized design 2x2x3 with 3 replications. The results showed that the combination NPK fertilizer and earthworm significantly (P<0.05) increased the productivity of the plant. The Quality of nutrition, crude protein and calcium (Ca), significantly increased (P<0.05) and respectively influenced by NPK fertilizer and lime. Whereas the crude fiber, very markedly decreased (P<0.01) in influenced by the interaction between NPK fertilizers and earthworm.
Keyword: Sorghum bicolor L. Moench,, NPK fertilizer, lime, latosol, Earthworm Eisenia foetida

Judul: Evaluasi Produktivitas Tanaman Sorghum (Sorghum bicolor) Varietas Numbu Terhadap Pemberian Vermikompos dan Cacing Tanah Eisenia foetida
Abstrak: Vermicompost is organic fertilizer which is created by worm contribution. Vermicompost can increase hara content that needed by plant to grow. This study was conducted to evaluate productivity of Sorghum bicolor (L.) Moench by adding vermicompost and worm Eisenia foetida in different level. The measured parameters in this study were plant height, amount of leaves, as fed weight, dry matter weight and nutrient quality that composed by N (Nitrogen), P (Phospor), and K (Potasium). The study was arranged by factorial completely randomized design 3x3 with 3 replications. The first factor was vermicompost addition level 0%, 12.5% and 25%, the second factor was Eisenia foetida worm addition level 0, 16 and 32 heads. The result showed that by 25% vermicompost adding, it increased productivity and nutrient quality of Sorghum bicolor plant (P<0.05). On the other hand, the addition of Eisenia foetida worm affected the vertical height of plants but it did not influence nutrient quality of Sorghum bicolor plant
Keyword: vermicompost., Sorghum bicolor (L.) Moench, Earthworm Eisenia foetida, Bogor Agricultural University (IPB)

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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