Judul: Slow Release Urea Nitrate with Zeolite Using Coating Method: In Vitro Study
Abstrak: Penelitian ini bertujuan untuk mengevaluasi pengaruh penyalut zeolit yang dilakukan secara in vitro pada urea-nitrat. Penelitian ini menggunakan rancangan acak kelompok (RAK) dengan 5 perlakuan dan 4 kelompok. Perlakuan terdiri dari P0 = ransum kontrol; P1 = P0 + urea tanpa coating; P2 = P0 + urea-nitrat tanpa coating; P3 = P0 + urea-nitrat dengan coating zeolit tanpa aktivasi; P4 = P0 + urea-nitrat dengan coating zeolit teraktivasi. Parameter yang diamati yaitu kecernaan bahan kering (KcBK), kecernaan bahan organik (KcBO), pH, volatile fatty acid (VFA), konsentrasi amonia (NH3), sintesis protein mikroba, dan produksi metana. Hasil penelitian menunjukkan bahwa pemberian ransum perlakuan tidak berpengaruh nyata (P>0,05) terhadap KcBK, KcBO, pH, VFA, sintesis protein mikroba, produksi gas total, dan produksi metana, tetapi berpengaruh nyata terhadap konsentrasi amonia. Pemberian coating zeolit pada urea-nitrat dapat menurunkan konsentrasi amonia dan tidak berdampak terhadap fermentasi rumen, kecernaan, sintesis protein mikroba, produksi gas, dan produksi metana., The research aimed to evaluate the effect of in vitro zeolite coating on urea-nitrate. 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 unactivated zeolite coating; P4 = P0 + urea-nitrate with activated zeolite coating. Parameters observed were dry matter digestibility (DMD), organic matter digestibility (OMD), pH, volatile fatty acid (VFA), ammonia concentration ( NH3), microbial protein synthesis, and methane production. The results showed that the application of urea-nitrate coating with zeolite had no significant effect (P>0,05) on DMD, OMD, pH, VFA, microbial protein synthesis, gas and methane production, but had a significant effect on ammonia concentrations. Applying a zeolite coating to urea-nitrate reduced ammonia concentrations and had no impact on rumen fermentation, digestibility, microbial protein synthesis, gas and methane production.
Keyword: ammonia, coating urea-nitrate, in vitro, methane, zeolite

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: 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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