Judul: Efek Populasi Cacing Eisenia foetida Savigny, Kapur dan Pupuk NPK terhadap Aspek Kualitas Nutrisi dan Produktivitas Centrosema pubescens Benth pada Latosol Dramaga.
Abstrak: Feed is one of important role on a farm, exspecially for livestock because its help animal to grow and make good performance. This research aimed to determine and to compare the effect of E. foetida population, lime and NPK fertilizer levels for nutrient quality and productivity of C. pubescens on Latosol Dramaga soil. The design of the experiment was Complete Randomized Design (CRD) with factorial pattern (2 x 2 x 3) and three replications. Factor 1 was level of NPK, factor 2 was level of lime and factor 3 was level of E. foetida population. The data were analyzed by using SAS version 9.0. The results showed that it was not significant on productivity (P>0.05) but it was significant on nutrient quality (P<0.05). C. pubescens had highest crude protein affected by lime, NPK factor and interaction between three factors. Calsium was significantly affected by lime, E. foetida population and interaction between three factors.
Keyword: nutrient quality and productivity, NPK fertilizer, lime, E. foetida population, latosol, C. pubescens

Judul: Pengaruh Pemberian Cacing Tanah Eisenia foetida pada Berbagai Umur Pertumbuhan Centrosema pubescens Benth pada Latosol Dramaga
Abstrak: Kesuburan tanah merupakan salah satu faktor yang mempengaruhi produktivitas tanaman pakan Centrosema pubescens. Cacing tanah Eisenia foetida sangat potensial dalam memperbaiki kesuburan tanah karena mampu merombak limbah organik dan dapat menambahkan unsur hara ke dalam tanah. Penelitian ini bertujuan untuk mengamati pengaruh pemberian cacing tanah E. foetida terhadap produktivitas dan kualitas C. pubescens pada masa pertumbuhan vegetatif pada latosol Dramaga. Penelitian ini terdiri dari 12 perlakuan dengan 3 kali ulangan. Rancangan percobaan yang digunakan adalah Rancangan Acak Lengkap (RAL) Faktor yang diberikan adalah level pemberian cacing tanah (0, 30 dan 60 ekor). Data dianalisis menggunakan analisis sidik ragam (ANOVA) dan untuk data yang berbeda nyata diuji lanjut menggunakan Duncan's Multiple Range Test (DMRT). Hasil penelitian menunjukkan adanya perbedaan nyata terhadap jumlah daun pada umur pertumbuhan 4, 6 dan 8 minggu setelah tanam (MST) dan tinggi vertikal pada umur 2 dan 4 MST (P<0.05). Pengaruh hanya terjadi pada umur pertumbuhan 6 dan 8 MST terhadap produksi biomassa bobot segar dan kering tanaman (P<0.05). Level pemberian cacing tanah mempengaruhi kandungan N dan P tanaman.
Keyword: Centrosema pubescens, Eisenia foetida

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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