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: Evaluasi Penambahan Cassabio ke dalam Ransum terhadap Konsumsi dan Kecernaan Zat Makanan pada Anak Domba Lokal.
Abstrak: Problems that are faced in farming development in Indonesia are providing feed raw materials, these are due to its low quantity and quality, as well as expensive in its price. The availability of feed raw material is also limited by its competition with human needs which are in line with the increase in its population, and by its dependent on imported products. Utilisation of agricultural byproduct, and improving its quality with applied technology, can be used as alternatives to overcome the problems. Cassava waste (onggok) is a byproduct of cassava flour industry with an increase in its amount relating to the increase in cassava flour industry. However, its use is limited by its low crude protein content, but its energy content is high, then it can be used as energy source feed. Improving nutritive value of cassava byproduct can be done by solid substrate fermentation with Aspergillus niger which is mixed with urea and ammonium sulphate as inorganic nitrogen sources. The product is known as cassabio, but the optimal use of cassabio in a ration has not yet been determined. Therefore, the experiment is carried out to evaluate cassabio addition into rations of local lamb at growth phase on nutrient digestibility. The experiment was conducted using randomized block design with four treatments and three replications, local lambs were used as replications. The treatments applied were addition levels of cassabio into concentrate at 0% (P0), 20% (P1), 40% (P2), and 60% (P3). Variables measured were digestibilities of dry matter, organic matter, crude protein, crude fiber, ether extract, nitrogen free extract, total digestible nutrients (TDN) and digestible energy (DE). Data were analysed with analysis of variance (ANOVA) and differences among treatments were determined with Duncan test. The results showed that the use of cassabio up to 60% (P3) in rations for local lamb at growth phase produced the best results on variables measured (digestibility and consumption). The highest nutrient consumption and digestibilities were obtained at 568.65 gram/day and 76.25% for organic matter, 394.45 gram/day and 82.39% for nitrogen free extract, and 86.28 gram/day and 76.25% for crude protein. The conclusion of this research is the use cassabio up to 60% into concentrate given are safe and the best results in local lamb.
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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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