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: Produktivitas dan Kualitas Nutrisi Sorghum bicolor (L.) Moench dan Centrosema pubescens Benth pada Pemberian Vermikompos Eisenia foetida Savigny
Abstrak: Vermicompost is one of organic materials that can increase nutrient contents in the soil. The aim of this study was to evaluate the productivity and nutrient quality of Sorghum bicolor (L.) Moench numbu variety and Centrosema pubescens Benth on some level vermicompost of Eisenia foetida Savigny earthworm. The parameters measured in this study were total of leaves, vertical height, fresh weight, dry weight, crude protein, phosphorus and potassium. This study used a completely randomized design with 3 replications to plants. The level of vermicompost is V0 (0%), V25 (25%), V50 (50%), V75 (75%) and V100 (100%). The type of plants used is Sorghum bicolor (L.) Moench and Centrosema pubescens Benth. Results showed that vermicompost was significant on plant productivity of both plants, whereas nutrition quality is just significant in Shorgum bicolor (L.) Moench.
Keyword: vermicompost, Sorghum bicolor, Centrosema pubescens

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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