Judul: Uji kelarutan dan ketersediaan biologis mineral mikro (Fe, Zn, Cu) dalam beberapa bahan pakan pada unggas
Abstrak: Penelitian ini dilakukan di Laboratorium Ilmu Nutrisi Ternak Unggas, Institut Pertanian Bogor dan Laboratorium Balai Penelitian Tanaman Pangan Bogor. Penelitian dimulai bulan Juli sampai dengan bulan September 1990. Tujuan penelitian adalah untuk menguji korelasi antara kelarutan mineral mikro (Fe, Zn, Cu) dalam buffer, air dan HCL (pH=2) dengan ketersediaan biologis mineral tersebut dari beberapa bahan pakan pada unggas. Buffer yang digunakan adalah campuran yang terdiri dari 5 liter air, 58.8 gram NaHCO3, 42 gram Na2HPO4.7H2O, 3.42 gram KC1, 2.82 gram NaCl, 0.72 gram MgSO4, dan 0.24 gram CaCl2. daun Bahan-bahan pakan yang diuji adalah daun ubi kayu, lamtoro, daun gamal, sorgum, bungkil inti sawit, tepung ikan. Chili, bungkil kacang tanah, tepung daging, bungkil kedele, tepung ikan lokal, bungkil kelapa, jagung, ampas kecap, dedak dan ampas tahu. Rataan kelarutan mineral mikro (Fe, Zn, Cu) dalam ketiga pelarut berturut-turut adalah 6.93% dalam air, 8.77% dalam buffer dan 44.26% dalam HCL (pH=2). Ketersediaan biologis Fe yang diperoleh dari hasil penelitian berkisar antara ((53.13%;90.73%)) dengan rataan sebesar 76.00%, ketersediaan biologis Zn berkisar antara ((37.26%;83.40%)) dengan rataan 68.32% dan ketersediaan biologis Cu berkisar antara ((83.58%;98.67%)) dengan rataan 92.04%. Korelasi antara kelarutan mineral Fe, Zn dan Cu dalam air, buffer dan HCL (pH=2) dengan nilai ketersediaan biologisnya tidak nyata. Masih diperlukan uji lain yang erat korelasinya untuk menduga ketersediaan biologis mineral.
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Judul: Hubungan antara kandungan asam fitat dalam bahan makanan nabati dengan ketersediaan biologis mineral Ca, P, Mg, dan Zn pada unggas
Abstrak: Penelitian ini dilakukan di Laboratorium Ilmu Nutrisi Ternak Unggas, Jurusan Ilmu Nutrisi dan Makanan Ternak, Fakultas Peternakan Institut Pertanian Bogor, Laboratorium Agronomi, Balai Fenelitian Tanaman Pangan, Cimanggu serta Laboratorium Kimia, Pusat Pengembangan Teknologi Pertanian, Kampus IPB Darmaga, dari bul an Juli sampai Oktober 1990. Tujuan penelitian ini adalah untuk mengetahui hubungan antara kandungan asam fitat dengan ketersediaan mineral Ca, P, Mg dan Zn secara biologis pada unggas. Sepuluh macam bahan makanan nabati (jagung, sorgum, padi, ampas kecap, bungkil kedelai, bungkil kacang dedak tanah, bungkil kelapa, bungkil inti sawit, tepung daun singkong dan tepung daun lamtoro) dianalisis kandungan asam fitatnya dengan metode Davies dan Reid (1979). Ketersediaan biologis mineral Ca, P, Mg dan Zn dari sepuluh bahan tersebut diuji menggunakan metode Nwokolo et al. (1976) yang dimodifikasi pada ayam jantan tipe petelur strain Babcock delapan minggu sebagai percobaan. Hubungan antara kandungan asam fitat ketersediaan biologis tiap mineral dilihat hewan dengan dengan menghitung koefisien korelasi antara kedua peubah tersebut. Kandungan asam fitat (% bahan kering) dari kesepul uh bahan makanan nabati tersebut adalah 0.74% (jagung), 0.30% (sorgum), 0.53% (dedak padi), 0.38% (ampas kecap), 0.33% (bungkil kedelai), 0.36% (bungkil kacang tanah), 0.27% (bungkil kelapa), 0.52% (bungkil inti sawit), 0.51% (tepung daun singkong) dan 0.44% (tepung daun lamtoro). Ketersediaan biologis mineral Ca, P, Mg dan Zn dari tiap-tiap bahan makanan adalah 57.6%, 56.5%, 50.0% dan 56.9% pada jagung; 62.5%, 55.6%, 31.8% dan 69.2% pada sorgum; 76.5%, 61.2%, 50.7% dan 47.7% pada dedak padi;...
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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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