Judul: Evaluasi Produksi Nh3 Dan H2s Feses Dengan Penambahan Palatability Enhancer (Pe) Dan Probiotik Dalam Ransum Sapi Pedaging
Abstrak: Penelitian ini bertujuan mengevaluasi produksi emisi gas dari kegiatan peternakan sapi potong, terutama amoniak (NH3) and hidrogen sulfida (H2S) dengan menggunakan probiotik yang ditambakan ke dalam ransum. Penambahan PE (palatability enhancer) di dalam ransum dapat mengingkatkan kualitas pakan dan meningkatkan palatabilatas pakan serta produktivitas ternak. Penelitian ini menggunakan rancangan percobaan rancangan acak kelompok (RAK) dalam 3 kelompok dengan setiap perlakuan terdapat 4 ekor sapi. Perlakuan terdiri atas P0 (kontrol), P1 (kontrol + PE 3% dari bobot konsentrat), P2 (kontrol + PE 3% dari bobot konsentrat + Probiotik (Sacharomyces cerevisae dengan dosis 5 x 1010 cfu kg-1 ransum dan MR4 dengan dosis 5 x 107 cfu kg-1 ransum). Data dianalisis menggunakan analisis ragam. Hasil menunjukan perlakuan P0, P1, dan P2 yang diberikan ke dalam ransum tidak signifikan (P> 0.05) dalam mengurangi produksi gas NH3 dan H2S dalam feses; perolehan IOFC yang terendah hingga tertinggi adalah P0, P1, dan P2.
Keyword: H2S, NH3, palatability enhancer (PE), probiotik

Judul: Efektivitas Penggunaan Probiotik Padat dan Cair untuk Menurunkan Kadar Amonia (NH3) dan Hidrogen Sulfida (H2S) Feses Sapi Potong
Abstrak: Livestock production system could result in various environmental problems which should be reduced. Faeces of beef cattle contain several odor producing compounds (ammonia, NH3, and hydrogen sulfide, H2S) that may have negative effect on animal production. Probiotic supplementation (solid and liquid probiotic) is one alternative for reducing nitrogen excretion and other noxious gas. The aim of this study was to asses the effectivity of solid and liquid probiotic supplementation for reducing fecal NH3 and H2S concentrations in beef cattle. Eighteen local beef cattle (average initial body weight, BW, 448.8±7.16 kg) were allocated into three dietary treatments in a randomized block design (six cattles per treatments). Dietary treatments included: P1 as conrol (forage+concentrate+rice bran); P2 (P1+solid probiotic 0.25% w/w); and P3 (P1+liquid probiotic 0.1% v/w). Results showed that probiotic addition decreased significantly faecal NH3 concentration (P<0.05), but had no effect on H2S concentration. Suplementation with solid probiotic was more effective for decreasing fecal NH3 concentration than liquid probiotic supplementation.
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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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