Judul: Kecernaan Nutrien, Retensi Nitrogen, dan Sintesis Protein Mikroba pada Domba yang Mendapat Substitusi Konsentrat dengan Silase Daun Singkong (Manihot esculenta sp.)
Abstrak: This research aimed to analyze the effect of substitution of concentrate with cassava leaves silage on nutrient digestibility, digestible energy (DE), nitrogen retention, daily gain, and microbial protein synthesis in Javanesse thin tailed sheep. The design experiment of this research based on completely randomized block design (4x4) using 16 sheeps of 5 months old with average body weight 11.47 ± 1.32 kg. They were placed in metabolic cage. The treatments were T0 (100% of napier grass), T1 (60% napier grass+40% concentrate), T2 (60% napier grass+20% concentrate+20% silage), and T3 (60% napier grass+40% silage). Substitution of concentrate with cassava leaves silage decreased (P<0.05) nutrients digestibilities, but did not affect digestible energy (DE). Substitution of concentrate with cassava leaves silage at level 20% in the ration have nitrogen retention higher (P<0.05) than treatment with 40% cassava leave silage in ration. Daily gain was similar among treatment. Substitution of concentrate with cassava leaves silage did not affect microbial protein synthesis. It is concluded that cassava leaves silage can substitute the use of concentrate by 50%.
Keyword: Sheep, Nitrogen Retention, Microbial Protein, Digestibility, Cassava Leaves Silage

Judul: Karakteristik Fermentasi Rumen dan Performa Domba Teradaptasi yang Diberi Pakan Silase Daun Singkong (Manihot esculenta sp.) dengan Taraf Berbeda
Abstrak: This experiment aimed to study the effect of provision of cassava leaves silage (CLS) as substitution for concentrate on rumen fermentation characteristics and performance of Javanesse Thin Tail Sheep. The experimental design used was block randomized design (4x4) using 16 male sheep of nine months old with body weight of 15.36 ± 2.59 kg and they were placed in the individual metabolic cage. The treatments were T0 (100% of napier grass), T1 (60% napier grass + 40% concentrate), T2 (60% napier grass + 20% concentrate + 20% CLS), and T3 (60% napier grass + 40% CLS). The results showed that provision of cassava leaves silage in the rations decreased (P<0.05) nutrient digestibility but increased (P<0.05) energy and protein consumption and rumen fermentability. Provision of CLS at level 20% (T2) had average daily gain, EPP, and IOFC similar to those of 40% concentrate treatment (T1). Provision of CLS at level 40% (T3) had average daily gain, EPP, and IOFC significantly lower (P<0.05) than those of 20% CLS and 40% concentrate treatment. It is concluded that CLS can be given at level of 20% of total ration which is equal to 50% concentrate. Feeding sheep only with napier grass do not fulfill their nutrient requirement for proper growth.
Keyword: Sheep, Rumen Fermentation Characteristics, Performance, Cassava Leaves Silage

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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