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: The Effectiveness of Oil as a Slow Release Urea Nitrate Coating Material on Fermentability, Digestibility and In Vitro Gas Production
Abstrak: Penelitian ini bertujuan untuk mengevaluasi efektivitas minyak sebagai coating slow release urea nitrat secara in vitro. Penelitian ini menggunakan rancangan acak kelompok (RAK) dengan 5 perlakuan dan 4 kelompok. Perlakuan terdiri dari P0 = ransum kontrol; P1 = P0 + urea; P2 = P0 + urea nitrat; P3 = P0 + urea nitrat dengan coating minyak sawit; P4 = P0 + urea nitrat coating minyak ikan. Parameter yang diamati yaitu pH, konsentrasi ammonia (NH3), volatile fatty acid (VFA), sintesis protein mikroba (SPM), koefisien cerna bahan kering (KCBK), koefisien cerna bahan organik (KCBO), produksi gas, dan gas metan. Analisis data menggunakan sidik ragam dengan perlakuan berbeda nyata dilakukan uji lanjut menggunakan uji Duncan menggunakan software SPSS versi 25. Hasil penelitian menunjukkan bahwa penggunaan slow release urea nitrat dengan coating minyak ikan dan minyak sawit tidak berpengaruh nyata (P>0,05) terhadap pH, NH3, SPM, VFA, KCBK, KCBO, total produksi gas, dan gas metan. Penggunaan SRUN dengan bahan coating minyak sawit dan minyak ikan belum efektif memengaruhi fermentabilitas, kecernaan dan produksi gas in vitro., This study aimed to evaluate the effectiveness of oil as a slow release urea nitrate coating in vitro. This study used a randomized block design (RBD) with 5 treatments and 4 groups. The treatment consisted of P0 = control ration; P1 = P0 + urea; P2 = P0 + urea nitrate; P3 = P0 + urea nitrate with palm oil coating; P4 = P0 + urea nitrate coating of fish oil. Parameters observed were pH, concentration of ammonia (NH3), volatile fatty acids (VFA), microbial protein synthesis (SPM), dry matter digestibility coefficient (KCBK), organic matter digestibility coefficient (KCBO), gas production, and methane gas. Data analysis using analysis of variance (ANOVA) and significantly different treatments were tested with the Tukey's test using SPSS software version 25. The results showed that the use of slow release urea nitrate with fish oil and palm oil coatings had no significant effect (P>0.05) on pH, NH3, SPM, VFA, KCBK, KCBO, amount of gas production and methane gas. The use of SRUN with palm oil and fish oil coatings has not effectively influenced in vitro fermentability, digestibility, and gas production.
Keyword: Coating, urea nitrate, in vitro, oil, slow release

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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