Judul: Pemberian Sinbiotik Ubi Jalar Merah dan Ragi Tape pada Periode Berbeda terhadap Kecernaan Nutrien dan Energi Termetabolis pada Ayam Broiler
Abstrak: This research aimed to observe the addition effects of synbiotic 3% red sweet potato meal and 0.75% tape yeast (fermented cassava) as feed additive on feed metabolizable energy and digestibility of broiler at different periods of rearing. Twenty four male of six weeks old broilers were used. The experimental design used was Completely Randomized Design (CRD) consisting of five treatments. P1 = Commercial diet, P2 = Basal diet, P3 = P2 + synbiotic (starterfinisher periode), P4 = P2 + synbiotic (starter periode), P5 = P2 + synbiotic (finisher periode) with four replicates. Variables measured were digestibility of dry matter, crude fat, crude fiber, metabolizable energy, and nitrogen retention. The results showed that the addition of synbiotic significantly increased (P<0.05) dry matter digestibility, crude fat digestibility, and metabolizable energy, but did not affected crude fiber and nitrogen retention . The synbiotic addition during starter periode showed the best effect on increasing dry matter digestibility and metabolizable energy
Keyword: Bogor Agricultural University (IPB), tape yeast, synbiotic, red sweet potato meal, production period, nutrient digestibilities, energy metabolizable

Judul: Performa Ayam Broiler yang diberi Sinbiotik Campuran Tepung Ubi Jalar Merah dan Ragi Tape pada Periode yang Berbeda
Abstrak: This research aimed to assess the effect of red sweet potato meal and tape yeast as a mixed synbiotic on performance of broiler in different periods. This experiment used 200 day old chicks (DOC) of broiler kept with litter system for 42 days. Data were analyzed using a completely randomized design with five treatments and four replicates, consisted of 10 broilers in each replicates. The treatment diets were P1 = commercial feed, P2 = basal feed, P3 = basal feed + 3% sweet potato meal + 0.75% tape yeast (starter-finisher periode), P4 = basal feed + 3% sweet potato meal + 0.75% tape yeast (starter periode), P5 = basal feed + 3% sweet potato meal + 0.75% tape yeast (finisher periode). Variables observed were daily intake, body weight gain, final body weight, feed convertion, PER, water intake, carcass percentage, mortality, IOFCC, temperature and humidity. The result showed there is no effect on all cumulative performance of broiler. The best used sinbiotic on starter periode. IOFCC in treatment P4 were more profitable than the other treatments. Addtion of sinbiotic reduced mortality rates compared to commercial feed.
Keyword: tape yeast, symbioti, red sweat potato meal, performance

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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