Judul: Utilization Tannin Chesnut (Castenia sp.) as a Protective Agent in Slow Release Nitrogen
Abstrak: Penggunaan urea sebagai penyumbang suplemen pakan utama karena memiliki harga yang murah, mudah dalam pengaplikasian, dan bermanfaat sebagai sumber nitrogen untuk sintesis protein mikroba. Urea memiliki kelemahan salah satunya dapat terhidrolisis cepat menjadi amonia. Solusi dari permasalahan tersebut maka dilakukan mekanisme yang dikenal dengan nitrogen lepas lambat menggunakan tanin jenis terhidrolisis. Penelitian ini bertujuan untuk mengevaluasi rumen in vitro terhadap perlindungan urea dengan menggunakan tanin komersil chestnut dalam berbagai taraf antara lain 0% (P0), 1% (P1), 2% (P2), 3% (P3) ke dalam pakan kontrol. Data dianalisis menggunakan analysis of variance dan perbedaan nyata antar perlakuan dilakukan uji tukey’s hsd test. Hasil penelitian menunjukkan tidak ada perbedaan statistik pada pH rumen, kecernaan bahan kering (KcBK), kecernaan bahan organik (KcBO), dan sintesis protein mikroba (SPM). slow release nitrogen (SRN) berbeda nyata (P<0,05) pada volatile fatty acid (VFA) total. Efek perlindungan berpengaruh negatif terhadap VFA total seiring dengan peningkatan taraf SRN. SRN berbeda sangat nyata (P<0,01) pada produksi amonia. Efek perlindungan berpengaruh negatif terhadap produksi amonia seiring dengan peningkatan taraf SRN. Kata kunci: nitrogen lepas lambat, tanin terhidrolisis, in vitro ABSTRACT FEGGIE. Utilization Tannin Chesnut (Castenia sp.) as a Protective Agent in Slow Release Nitrogen. Supervised by ANURAGA JAYANEGARA and KOMANG GEDE WIRYAWAN. Urea has become indispensable for supplying the necessary feed supplement because of cheap, easy to use, and had a benefit as nitrogen sources for microbial protein synthesis. Urea have a weakness to readly hydrolyzable into amonia. For the solution with use the mechanism that we called slow release nitrogen with hydrolyzable tannin. This experiment was conducted to evaluate in vitro rumen on different levels of tannin chestnut such as 0% (T0), 1% (T1), 2%(T2), 3%(T3) into a control diet. Data were analysed using analysis of variance and any significant different further tested using tukey’s honest significant difference Test. Results this experiment showed addition of different concentration of tannin chestnut as urea protector did not affect with any parameters in pH rumen, dry matter digestibility, organic matter digestibility, and microbial protein synthesis. However, the addition of different concentration of tannin chestnut have negative effects on volatile fatty acid (VFA) total production (P<0,05) and amonia production (P<0,01). Keywords: hydrolyzable tannin, in vitro, slow relase nitrogen
Keyword: hydrolyzable tannin, in vitro, slow release nitrogen

Judul: Evaluation of Balanced Urea and Nitrate Ratio with Slow  Release Urea Nitrate (SRUN) as Ruminant Feed Additive: In Vitro
Abstrak: Rendahnya kandungan protein dari bahan pakan menjadi salah satu faktor penghambat peningkatan produktivitas ternak ruminansia. Oleh karena itu, perlu adanya suplementasi protein pada pakan ternak ruminansia agar protein pada ternak dapat terpenuhi sehingga ternak berproduksi secara optimal. Urea dan nitrat merupakan sumber NPN yang biasa diberikan pada pakan tambahan ruminansia. Urea merupakan NPN yang digunakan sebagai pengganti pakan protein murni, karena memiliki harga yang terjangkau dan dapat menekan biaya pakan ternak. Sedangkan Nitrat (NO3 - ) adalah penghambat metana yang efektif dan sumber NPN potensial untuk ternak, bertindak sebagai penyerap H2 dan menambahkan nitrogen berbasis amonia ke rumen. Pemanfaatan urea dan nitrat dalam nutrisi ruminansia terbatas karena hidrolisisnya yang cepat menjadi amonia dalam rumen, sehingga perlu dilakukan teknologi pelapisan atau coating dengan polimer lain seperti zeolit dengan metode SRUN yang dapat mengontrol degradasi urea-nitrat dan pelepasan NH3 ke dalam rumen. Penelitian ini bertujuan mengembangkan inovasi SRUN, serta mengevaluasi imbangan rasio urea-nitrat sebagai pakan aditif ruminansia yang berfungsi untuk stimulator sintesis protein mikroba rumen dengan metode in vitro. Penelitian ini menggunakan rancangan acak kelompok (RAK) dengan 11 perlakuan dan 4 kelompok sebagai ulangan. Data dianalisis menggunakan ANOVA dan diuji lanjut dengan uji Duncan menggunakan software SPSS 25. Hasil penelitian menunjukkan pengaruh berbeda nyata (P<0,05) terhadap parameter yaitu kecernaan bahan kering dan bahan organik, pH, produksi gas total, gas metan, NH3, dan sintesis protein mikroba. Hasil terbaik seluruh parameter seperti kecernaan, pH, produksi gas, gas metan, NH3, sintesis protein, populasi mikroba, mikroba, dan VFA ditunjukkan oleh perlakuan P2 dan P10. Disimpulkan bahwa perlakuan P2 (P0 + Coating nitrat 2%) dan P10 (P0 + Coating urea:nitrat (2:1) 4%) dapat menjadi agen mitigasi metana dan menjadi stimulator sintesis protein mikroba rumen., The low protein content of feed ingredients is one of the inhibitors for increasing the productivity of ruminants. Therefore, there is a need for protein supplementation in ruminant feed so that the protein in livestock can be fulfilled and produced optimally. Urea and nitrate are NPN sources that are usually given to ruminant feed additives. Urea is an NPN that is used as a substitute for pure protein feed, because it has an affordable price and can reduce the cost of animal feed. Nitrate (NO3 - ) is an effective methane inhibitor and a potential NPN source for livestock, acting as an H2 sink and adding ammonia-based nitrogen in the rumen. Utilization of urea and nitrate as ruminant feed is limited due to the rapid hydrolysis into ammonia in the rumen. So, it is necessary to apply coating technology using polymers such as zeolite using the SRUN method, which can control the degradation of urea-nitrate and the release of NH3 into the rumen. This study aims to develop innovative SRUN, as well as evaluate the balance of the urea-nitrate ratio as a feed additive for ruminants which functions as a stimulator of rumen microbial protein synthesis using in vitro methods. This study used a randomized block design (RBD) with 11 treatments and 4 groups as replications. Data were analyzed using ANOVA and further tested with Duncan's test using SPSS 25 software. The results showed a
Keyword: ammonia, coating urea-nitrate, non-protein nitrogen, zeolite

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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