Judul: Kajian Perkembangan Perdagangan GUM Xanthan sebagai Bahan Pengental untuk Industri Pangan di Indonesia
Abstrak: Salah s a t u bahan tambahan m3kanan yang merupakan produk i n d u s t r i dan selarna i n i masih diimpor oleh Indonesia adalah biopolimer. Jenis biopolimer yang memiliki prospek cerah dalam pasaran dalam negeri dan luar negeri adalah gum xanthan dengan n i l a i komersial t i n g g i karena kegunaannya yang luas pada berbagai i n d u s t r i . Produksi gum xanthan dunia diperkirakan sebesar 25000 ton (Galindo, 1994). Menurut Peraturan Menteri Kesehatan RI No.722/ MENKES/PER,/IX/88 ( 1990 ) tentang Bahan Tamballan Makanan, gum xanthan dimasukkan dalam golongan pengemulsi, pemantap 3tau pengental . Impor bahan pengental ke Indonesia berdasarkan kebutuhan nasional h a s i l s u r v e i Biro Fusat S t a t i s t i k d a r i tahun 1989 hingga 1993 menunjukkan data pertumbuhan kuantit a s r a t a - r a t a bahan pengental pertahun sebesar 46.7 persen dan pertumbuhan rata-rata n i l a i impor 37.7 persen (CIF) .
Keyword: 

Judul: Produksi Gum Xanthan Berbasis Limbah Padat Singkong oleh Xanthomonas campestris.
Abstrak: Xanthan adalah polisakarida yang dihasilkan oleh Xanthomonas campestris, bakteri Gram negatif aerob obligat. Sifat yang unik ini membuat gum xanthan banyak diaplikasikan sebagai stabilizer, pengemulsi, pengental, dan zat tambahan dalam pengeboran minyak. Biaya dalam proses produksi gum xanthan perlu ditekan, salah satunya dengan mengganti sumber karbon dengan limbah padat singkong. Penelitian ini bertujuan menentukan konsentrasi optimum limbah padat singkong yang dapat menghasilkan rendemen gum xanthan tertinggi. Konsentrasi limbah padat singkong yang digunakan dalam penelitian ini adalah 10 g/L, 20 g/L, 30 g/L, dan 40 g/L yang diperoleh dari pengenceran limbah padat singkong. Gula pereduksi diukur dengan metode DNS dan diperoleh gula pereduksi pada konsentrasi limbah padat singkong 40 g/L sebanyak 2.124 g/L. Biomassa sel dan bobot gum xanthan tertinggi terdapat pada konsentrasi limbah padat singkong 40 g/L. Konsumsi biomassa sel tertinggi terukur pada jam ke-16 sebesar 26.54 g/L dan gum xanthan tertinggi terdapat pada jam ke-16 yaitu sebesar 25.76 g/L
Keyword: Biomass cells, xanthan gum, cassava solid waste

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: