Judul: Persamaan Lokta-Volterra untuk Menduga Pertumbuhan Lactobacillus bulgaricus dan Streptococcus thermophilus dalam Biakan Murni dan Campuran pada Proses Pembuatan Yoghurt
Abstrak: Karya ilmiah ini hartqjuan untuk memhandingkan tiga huah matode yang digunakan untuk membandingkan tiga paramater model pertumhuhan hakteri Lactobacillus bulgaricus dan Streptacocrus thermophilus dalam biakan murni pada proses pambuatan yoghurt. Selanjutnya dengan metode Isocline dan anak panah, nilai-nilai dugaan parameter yang diperoleh digunakan untuk mengetallui hentuk interaksi kedua hakteri dalani hiakan campuran. Adapun metode yang dihandingkan adalah metode Aproksimasi, Pelinzaran, dan Non0 Linear SAS.
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Judul: Perbedaan derajat asam dan aspek fisik youhurt dengan penggunaan starta yang berbeda
Abstrak: Tujuan penelitian ini adalah untuk melihat perbeda- an derajat asam dan aspek fisik dari yoghurt yang diino- kulasikan dengan starter Lactobacillus bulgaricus, Lactobacillus acidophilus, Streptococcus thermophilus baik dengan biakan murni atau campuran diantara ketiganya, selain daripada itu untuk melihat kombinasi starter yang memperlihatkan hasil yang lebih baik. Penelitian dilaksanakan di Laboratorium Kesehatan Masyarakat Veteriner Fakultas Kedokteran Hewan, Institut Pertanian Bogor pada bulan Januari 1988. Ketiga jenis bakteri yaitu Lactobacillus bulgaricus, Lactobacillus acidophilus dan Streptococcus thermophilus diteliti dalam enam macam perlakuan yakni biakan murni masing-masing bakteri dan kombinasi campuran kedua jenis bakteri (Lactobacillus bulgaricus dengan Lactobacillus acidophilus; Lactobacillus bulgaricus dengan Strepto- coccus thermophilus; Lactobacillus acidophilus dengan Streptococcus thermophilus). Perubahan yang diamati antara lain aspek fisik yang timbul sebagai hasil kerja starter dan pengukuran derajat asam yang merupakan indikator pertumbuhan dari bakteri. Hasil analisa menunjukkan adanya perbedaan derajat asam dan aspek fisik pada yoghurt yang menggunakan star- ter berbeda pada waktu dan tempat yang sama. Umumnya di peroleh derajat asam yang lebih tinggi dan aspek fisik yang sifatnya lebih baik pada biakan campuran. Sedangkan dari hasil penelitian didapatkan kombinasi starter yang lebih baik digunakan untuk pembuatan yoghurt berturut- turut Lactobacillus acidophilus dengan Streptococcus thermophilus; Lactobacillus bulgaricus dengan Strepto- coccus thermophilus; Lactobacillus acidophilus; Lactoba- cillus acidophilus dengan Lactobacillus bulgaricus; Streptococcus thermophilus dan yang terakhir Lacto- bacillus bulgaricus….
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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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