Judul: Uji Kualitas Fisik Pellet Berbasis Jerami Jagung Sebagai Pakan Sumber Serat untuk Ternak Ruminansia
Abstrak: Pemanfaatan produk samping (by product) tanaman jagung seperti jerami jagung yang tersedia secara melimpah dapat menjadi alternatif bahan baku pakan pengganti hijauan yang ketersediaannya saat ini sudah semakin terbatas. Namun, jerami jagung memiliki keterbatasan yaitu, kandungan zat makanan yang rendah, kecernaan yang rendah serta bersifat bulky (voluminous) sehingga tidak efisien jika diangkut ke daerah lain. Untuk meningkatkan nilai zat makanan jerami jagung tersebut dapat dicampur dengan bahan pakan lain sebagai sumber protein dan energi seperti leguminosa dan jagung. Salah satu leguminosa yang memiliki kandungan protein yang tinggi dan memiliki produksi tinggi adalah legum Indigofera sp. selain lebih efisien, pellet lebih mudah dalam penanganan (handling) dan transportasi. Untuk menghasilkan pakan bentuk pellet, maka kajian tentang sifat-sifat fisik bahan sangat diperlukan seperti kerapatan tumpukan, kerapatan pemadatan tumpukan, berat jenis, sudut tumpukan, dan laju alir. Sementara itu, untuk mengevaluasi kualitas fisik pellet dapat diukur dari pellet durability index (PDI). Penelitian ini bertujuan untuk mengetahui sifat fisik bahan baku pellet dan mengetahui pengaruh komposisi bahan baku pellet dan ukuran die terhadap kualitas fisik pellet. Penelitian ini menggunakan rancangan acak lengkap faktorial dengan model 4 x 2 dengan 3 ulangan. Faktor A merupakan komposisi bahan pellet dengan perlakuan A1 (100% jerami jagung), A2 ( 75% jerami jagung + 20% Indigofera Sp. + 5 % jagung giling), A3 ( 75% jerami jagung + 15% Indigofera Sp. + 10 % jagung giling), A4 ( 75% jerami jagung + 10% Indigofera Sp. + 15 % jagung giling), dan faktor B adalah ukuran die yaitu 5 dan 8 mm. Peubah yang diamati adalah kerapatan tumpukan, kerapatan pemadatan tumpukan, berat jenis, sudut tumpukan, laju alir, dan pellet durability index (PDI). Data analisa menggunakan ANOVA, apabila terdapat perbedaan yang nyata akan dilanjutkan menggunakan uji Duncan (Steel dan Torrie, 1993).
Keyword: corn plant by product, lignoselulose by product, processing technology, Completely Randomized Design with factorial, bulk density, specific density, specific density, specific density, pellet durability index

Judul: Uji Kualitas Sifat Fisik dan Daya Simpan Pellet yang Mengandung Klobot Jagung dan Limbah Tanaman Ubi Jalar sebagai Substitusi Daun Rumput Gajah.
Abstrak: This study aims measured the quality of the physical properties and storage period of pellet. Food resources in the form of pellet with corn husk and sweet potato by-product as a substitute for the Pennisetum purpureum leaves. Model experiments used a Completely Randomized Design with (4x4) factorial and 4 replicates. The first factor was the rate of substitution consist of R0 (18% Pennisetum purpureum leaves + 82% concentrate), R1 (12% Pennisetum purpureum leaves + 3% corn husk + 3% sweet potato by-product + 82% concentrate), R2 (6% Pennisetum purpureum leaves + 6% corn husk + 6% sweet potato by-product + 82% concentrate), R3 (9% corn husk + 9% sweet potato by-product + 82% concentrate). The second factor was the storage period consist of Q1 (0 weeks), Q2 (2 weeks), Q3 (4 weeks) and Q4 (6 weeks) with four replications. The variables observed were water content (%), density (gr/cm3), loose bulk density (gr/cm3), compacted bulk density (gr/cm3), single of repose (), water activity, particle size (mm) and pellet durability index (%). Data were analyzed by analysis of variance and significant results with orthogonal contrast test. The results showed that corn husk and sweet potato by-product as a substitute for the Pennisetum purpureum leaves and storage period of significant effect (P<0.01). Differences of each level of substitution affecting for water content, water activity, particle size, angle of repose and loose bulk density. Interaction of two factors were significant effect (P< 0.01). According to change of pellet water activity, the best results from first factor were R1. While the second factor as good as the rations not stored more than 2 weeks.
Keyword: 

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.
Keyword: