Judul: Slow-release urea in rice straw based diets to increase efficiency of bali cattle production
Abstrak: Urea merupakan sumber nitrogen bukan protein (NPN) yang paling sering digunakan untuk menggantikan sebagian dari protein ransum pada ruminansia. Namun karena urea bersifat mudah terhidrolisis menjadi amoniak di dalam rumen dan dengan cepat pula diserap memasuki sistem darah, maka dalam praktiknya penggunaan urea dapat berdampak negatif bagi ternak, mulai dari penurunan konsumsi dan performa ternak sampai kematian akibat keracunan urea. Upaya untuk mengoptimalkan nilai guna dari urea sebagai sumber NPN yang ekonomis bagi ruminansia harus mempertimbangkan dampak negatif dari sifat urea tersebut. Pada penelitian ini, upaya tersebut diwujudkan dengan menguji tiga macam produk urea lepas-lamban, yakni: urea-seng sulfat (US), urea-zeolit (UZ), dan urea-seng sulfat-zeolit (USZ) yang diuji dalam tiga tahap (preparasi dan penentuan sifat produk, in vitro, dan in vivo). Penelitian tahap pertama bertujuan mempelajari kelarutan preparat US, UZ, dan USZ sebagai suplemen sumber NPN lepas-lamban pada ruminansia. Pada tahap ini, zeolit dipanaskan pada suhu 100 0C lalu kerapatan ruah dan keporiannya diukur untuk menentukan daya serapnya. Selanjutnya, urea dicampurkan dengan zeolit, seng sulfat, atau zeolit dan seng sulfat dengan metode pelelehan urea pada suhu 80 – 110 0C. Rasio urea:zeolit ditetapkan berdasarkan daya serap zeolit, sedangkan rasio urea:seng sulfat ditetapkan berdasarkan reaksi pembentukan kompleks urea-seng sulfat. Produk yang dihasilkan lalu dipindai dengan scanning electron microscopy untuk mengetahui tingkat ketercampuran antara zeolit dan urea. Produk tersebut dilarutkan dalam larutan McDougall dan kelarutan nitrogennya diukur pada rentang waktu: 0, 0.25, 0.5, 0.75, 1, 2, 4, 6, 8, 10, 12, 24, dan 48 jam. Rancangan percobaan yang digunakan untuk uji kelarutan ini adalah Rancangan Acak Lengkap dan setiap perlakuan terdiri atas 2 ulangan.
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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: Thermal Characteristics and Dynamics of Tropical Cyclone over Western North Pacific Ocean: A Case Study of Typhoon Songda (Chedeng) 2011
Abstrak: The frequent occasion of Tropical Cyclone (TC) over Western North Pacific (WNP) Ocean lies from 10˚N to 26˚N and 121˚E to 170˚E. Sources of TC development come from warm ocean temperature where latent heat is released during condensation processes and subsequently concentrated in the boundary layer. Relative humidity at 850-700 hPa is responsible to produce the most intense storm. Meanwhile, weak vertical wind shear between 850-200 hPa is one of the dynamical factors that lead to the development of TC. Pressure level of 850-200 hPa is chosen to minimize the thermodynamic effect in the lower troposphere. Typhoon Songda (Chedeng in the Philippines) or TSC lasted from May 18th to 30th, 2011 and strengthened into powerful Super Typhoon stage between May 24th and 27th. Long curving track and the exhibition of all sequences of TC life cycle, TSC is then considered as an ideal case of TC. The objective of the study with case of TSC is to investigate the role of thermal characteristics and dynamics on TC intensity. The research is carried out by using Advanced Research of Weather Research and Forecasting model (WRF ARW model) version 3.3. Two domains are employed in the model. The first domain situate from 02˚N to 40˚N and 118˚E to 149˚E and cover spatial resolution () of 33.1 km. The second domain situate from 09˚N to 27˚N and 119˚E to 132˚E with of 11 km. Timestep of the model () is 120 seconds. The model is supported by the following physical parameterization, i.e., Yonsei University Scheme (YSU) in the boundary layer, Kain-Fritsch scheme (KF) in the cumulus, and WRF Single-Moment 3-class scheme in the microphysics. Initial meteorological condition prior to the formation of the cyclone is generated using WRF ARW standard-release model. Sensitivity of the model output is obtained from a selected single-parameter change scenarios, namely, 10 % to 20 % decrease and increase of wind shear initial data at 850-200 hPa, and by 10 % to 20 % decrease of relative humidity initial data at 850-700 hPa. The result showed that the negative correlations between wind shear and intensity are found in wind shear scenarios. Wind shears of 10 ms-1 which lead to strengthening of the wind intensity in the early period of Typhoon development are found in wind shear scenarios. The effect of wind shear changes on wind intensity is statistically significant in the 20 % wind shear scenarios. During mature stage, weak wind intensity occurred when wind shear increase as given in the WRF standard-release and the 20 % decreasing scenario. Different situation is found in the 20 % increasing scenario where wind shear tend to weak and lead to strong wind intensity at this stage. Meanwhile, the reduction of moisture supply at 850-700 hPa resulting from 20 % decreasing relative humidity play a major role in the weakening of wind intensity and reduces mechanical energy of the cycle process as much as 300 J kg-1.
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