Judul: Fermentability, Digestibility and Methane  Production of Some Variety Panicum maximum Different Age Harvest
Abstrak: Analisis kecernaan in vitro adalah metode yang dilakukan secara tidak langsung dengan mengadaptasi dari proses yang ada di dalam saluran pencernaan ruminansia. Penelitian ini bertujuan untuk mengevaluasi beberapa varietas rumput benggala melalui pengukuran fermentabilitas, kecernaan dan produksi gas metan dari umur berbeda. Rancangan acak lengkap pola faktorial 3x3 dengan dua faktor. Faktor pertama adalah varietas tanaman dan faktor kedua adalah umur panen. Pengelompokan berdasarkan cairan rumen yang dilakukan secara duplo. Parameter yang diukur (KCBK, KCBO, VFA total, NH3, CH4) dianalisis dengan analisis sidik ragam kemudian dilanjutkan dengan uji Duncan, Polinomial Ortogonal dan Regresi. Hasil data menunjukan varietas dan umur panen sangat signifikan (P<0,01) terhadap KCBK, KCBO, VFA, dan NH3 kecuali CH4 (P>0,05). Adapun rataan masing-masing varietas (Trichoglume; Gatton; Mombasa) pada KCBK 50,69; 55,51; 56,18%, KCBO 54,59; 59,08; 59,06%, VFA total 97,59; 144,05; 114,61 mM, NH3 8,95; 16,80; 12,79 mM, dan CH4 55930,97; 47543,40; 48944,10 ppm., In vitro analysis is a method that is carried out indirectly by simulation the existing processes in the digestive tract of ruminants to find the potential nutritious feed. This research aim was to evaluate the fermentability, digestibility, and methane production of some variety Panicum maximum from different age harvest. A Random design complete in factorial pattern 3x3 with two factors. The first factor was the variety of forage and the second factor was the age of harvest. Grouping based on rumen fluid, and the experiment was done in duplicate. The variables measured (KCBK, KCBO, total VFA, NH3, CH4) were analyzed using ANOVA continued with Duncan's test, Orthogonal Polynomial and Regression. The finding results showed that DMD, OMD, total VFA and NH3 were very significantly affected by variety and harvest age (P<0,01) except for CH4 (P>0,05). The average of each variety (Trichoglume; Gatton; Mombasa), DMD 50.69; 55.51; 56.18%, OMD 54.59; 59.08; 59.06%, total VFA 97.59; 144.05; 114.61 mM, NH3 8.95; 16.80; 12.79 mM, and CH4 55930.97; 47543.40; 48944.10 ppm.
Keyword: in vitro, Panicum maximum, umur panen, varietas, harvest age, variety

Judul: Utilisasi Silase Jerami Jagung dengan Suplementasi Kulit Matoa terhadap Penurunan Produksi Gas Metan secara In Vitro
Abstrak: Penelitian ini bertujuan untuk menganalisis pengaruh jerami jagung dengan suplementasi kulit matoa terhadap fermentabilitas dan kecernaan rumen secara in vitro. Penelitian menggunakan rancangan acak lengkap (RAL) dengan 4 perlakuan dan 4 ulangan. Perlakuan meliputi P0 = 1 kg jerami jagung; P1 = 1 kg jerami jagung + 20% kulit matoa; P2 = 1 kg jerami jagung + 30% kulit matoa; P3 = 1 kg jerami jagung + 40% kulit matoa. Parameter yang diamati yaitu analisis proksimat, gas total, gas metana, pH rumen, volatile fatty acid (VFA), NH3, sintesis protein mikrobial (SPM), kecernaan bahan kering (KcBK), kecernaan bahan organik (KcBO), total bakteri, dan populasi protozoa. Data dianalisis menggunakan analysis of variance (ANOVA) dan diuji lanjut dengan Uji Duncan menggunakan program SPSS 25. Perlakuan tidak berpengaruh nyata terhadap pH rumen, kadar NH3, SPM, KcBK, dan KcBO. Namun, berpengaruh nyata pada total produksi gas total, penurunan gas metan, dan konsentrasi VFA. Silase jerami jagung dengan suplementasi kulit matoa efektif menurunkan gas metan, tetapi tidak mempengaruhi fermentabilitas dan kecernaan rumen., This study aimed to analyze the effect of corn straw silage with matoa peel supplementation on fermentability and rumen digestibility in vitro. This study used a completely randomized design (CRD) with 4 treatments and 4 replications. The treatments consisted of P0 = 1 kg corn straw; P1 = 1 kg corn straw + 20% matoa peel; P2 = 1 kg corn straw + 30% matoa peel; P3 = 1 kg corn straw + 40% matoa peel. Parameters observed were proximate analysis, gas production, methane gas, rumen pH, volatile fatty acid (VFA), NH3, microbial protein synthesis (MPS), dry matter digestibility (DMD), organic matter digestibility (OMD), total bacteria, and protozoa population. Data were analyzed using analysis of variance (ANOVA) and further tested with Duncan's test using the SPSS 25 program. The treatment had no significant effect on rumen pH, NH3 levels, MPS, DMD, and OMD. However, the treatment had a significant effect on total gas production, methane gas reduction, and VFA concentration. Corn straw silage with matoa peel reduced methane gas but it did not affect on rumen fermentability and digestibility.
Keyword: fermentabilitas, in vitro, jerami jagung, kulit matoa, Metan

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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