Judul: Slow Release Urea Nitrate with Starch Polymer Coating Technique for Fermentation and Rumen Digestibility In Vitro, Slow Release Urea Nitrate with Starch Polymer Coating Technique for Fermentation and Rumen Digestibility In Vitro
Abstrak: Penelitian ini bertujuan untuk mengevaluasi pengaruh teknik penyalut polimer amilum yang dilakukan secara in vitro pada urea-nitrat sebagai bahan pakan aditif bagi ruminansia. Penelitian ini menggunakan rancangan acak kelompok (RAK) dengan 5 perlakuan dan 4 kelompok. Perlakuan terdiri dari P0 = ransum kontrol; P1 = P0 + urea tanpa penyalut; P2 = P0 + urea-nitrat tanpa penyalut; P3 = P0 + urea-nitrat dengan penyalut pati sagu; P4 = P0 + urea-nitrat dengan penyalut pati singkong. Parameter yang diamati yaitu kecernaan bahan kering (KCBK), kecernaan bahan organik (KCBO), pH, volatile fatty acid (VFA), konsentrasi amonia (NH3), sintesis protein mikroba, total gas produksi dan produksi gas metan. Hasil penelitian menunjukkan bahwa pemberian ransum perlakuan tidak berpengaruh nyata (P>0,05) terhadap KCBK, KCBO, pH, VFA, sintesis protein mikroba, total produksi gas dan produksi gas metan, tetapi berpengaruh nyata terhadap konsentrasi NH3. Penambahan urea-nitrat dengan penyalut pati singkong dapat menurunkan konsentrasi amonia dan tidak berdampak terhadap fermentasi, kecernaan rumen dan produksi gas metan., This research aimed to evaluate the effect of starch polymer coating techniques carried out in vitro on urea-nitrate as a feed additive for ruminants. This study used a randomized block design (RBD) with 5 treatments and 4 groups. The treatment consisted of P0 = control ration; P1 = P0 + uncoated urea; P2 = P0 + uncoated urea-nitrate; P3 = P0 + urea-nitrate with sago starch coating; P4 = P0 + urea-nitrate with cassava starch coating. Observed parameters were dry matter digestibility (DMD), organic matter digestibility (OMD), pH, volatile fatty acids (VFA), ammonia concentration (NH3), microbial protein synthesis, total gas production and methane production. The results showed that the treatment ration had no significant effect (P>0.05) on DMD, OMD, pH, VFA, protein synthesis microbes, total gas production and methane production, but had a significant effect on NH3 concentrations. The addition of urea-nitrate coating with cassava starch can reduce ammonia concentrations and has no impact on fermentation, rumen digestibility and methane gas production.
Keyword: ammonia, coating urea-nitrat, in vitro, methane, starch

Judul: Fermentability and Digestibility of Feed Added Slow Relase Urea-Nitrate In Vitro.
Abstrak: Penelitian ini bertujuan menguji pengaruh penambahan slow release urea-nitrat dalam ransum secara in vitro. Penelitian ini menggunakan rancangan acak kelompok 5 perlakuan dan 4 ulangan. Perlakuan terdiri dari P0 = ransum kontrol; P1 = P0 + urea; P2 = P0 + urea-nitrat; P3 = P0 + urea-nitrat dilapisi dengan molases; P4 = urea-nitrat dilapisi dengan limbah cair sari kurma. Peubah yang diamati adalah kecernaan bahan kering (KcBK), kecernaan bahan organik (KcBO), konsentrasi amonia (NH3), derajat keasaman (pH), volatile fatty acid (VFA) total, sintesis protein mikroba (SPM), total produksi gas, dan gas metan. Data dianalisis menggunakan analysis of variance (ANOVA) dan perlakuan yang berbeda nyata akan dilakukan uji lanjut dengan uji duncan menggunakan statistical product and service solutions (SPSS) 25. Hasil penelitian menunjukkan bahwa perlakuan tidak berpengaruh nyata (P>0,05) terhadap nilai KcBK, KcBO, VFA total, pH, SPM, total produksi gas, dan gas metan. Perlakuan yang berpengaruh nyata (P<0,05) adalah konsentrasi amonia (NH3). Simpulan penelitian ini adalah penambahan slow release urea-nitrat belum mampu menurunkan konsentasi amonia., This study aimed to examine the effect of the addition slow release urea-nitrate in rations in vitro. This study used a randomized block design with 5 treatments and 4 replications. The treatment consisted of P0 = control ration; P1 = P0 + Urea; P2 = P0 + urea-nitrate; P3 = P0 + urea-nitrate coated with molasses; P4 = urea-nitrate coated with palm juice liquid waste. The observed variables were dry matter digestibility (KcBK), organic matter digestibility (KcBO), ammonia concentration (NH3), degree of acidity (pH), total volatile fatty acid (VFA), microbial protein synthesis (SPM), total gas production, and methane gas. Data were analyzed using analysis of variance (ANOVA) and significantly different treatments would be further tested with Duncan's test using statistical product and service solutions (SPSS) 25. The results showed that the treatment had no significant effect (P>0.05) on the KcBK, KcBO, total VFA, pH, SPM, total gas production, and methane gas. The treatment that had a significant effect (P<0.05) was the concentration of ammonia (NH3). The conclusion of this study was the addition of slow release urea-nitrate has not been able to reduce the concentration of ammonia.
Keyword: ammonia concentration, in vitro, methane gas, slow release urea-nitrate

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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