Judul: Pengaruh konsentrasi koh dan jumlah air terhadap pembentukan gel dari rumput laut jenis Gracilaria sp.
Abstrak: Penelitian ini bertujuan untuk mengetahui proses pembuatan agar-agar kertas dan pengaruh konsentrasi KOH dan jumlah air terhadap pembentukan gel agar-agar. Pene- litian dilakukan dalan dua tahap yaitu penelitian pendahu- luan dan penelitian utama. Penelitian pendahuluan bertu- juan untuk menentukan komposisi kinia bahan baku, memban- dingkan antara perlakuan KOH dan perlakuan KCl dan mencari konsentrasi KOH ninimun supaya agar-agar dapat menjendal. Pada penelitian utama nempelajari pengaruh konsentrasi KOH (0,06; 0,08; 0,10; 0,12 gr/ml) dan jumlah air (21, 23, 25 kali berat rumput laut kering gudang) terhadap rendemen, kadar abu, kadar air, kadar galaktosa, kekuatan gel, titik pembentukan gel, titik leleh gel dan organoleptik (penam- pakan, bau dan konsistensi). Sebagai data tambahan logamberat pb dan protein. Rancangan percobaan yang digunakan pada penelitian utama adalah rancangan acak lengkap faktorial 4 x 3 dengan dua kali ulangan. Dari hasil penelitian pendahuluan, perlakuan dengan KOH lebih baik dibanding dengan perlakuan KCl dan konsen- trasi KOH yang minimun supaya agar-agar dapat menjendal yaitu konsentrasi кон 0,06 gr/ml. Analisa ragam ...
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Judul: Pengaruh penambahan asam cuka (CH3COOH) dan lama perendaman terhadap mutu agar-agar dari rumput laut Gracilaria Gerrucosa
Abstrak: Rumput laut Gracilaria verrucosa merupakan salah satu jenis ganggang merah yang potensial sebagai penghasil agar- agar. Penggunaan agar-agar saat ini sangat luas, antara lain untuk industri makanan, farmasi dan kosmetika. Metode ekstraksi dan perlakuan yang diberikan sebelum dan selama proses sangat menentukan rendemen dan mutu agar-agar yang dihasilkan. Penelitian ini bertujuan untuk mendapatkan konsentrasi asam. cuka (CH3COOH) dan lama perendaman yang optimal serta pengaruhnya terhadap rendemen dan mutu agar-agar yang dihasilkan. Pengamatan yang dilakukan adalah rendemen dan analisis mutu, yaitu: logam berbahaya, kadar air, kadar abu, kekuatan gel, kadar karbohidrat, gelling point (suhu pemben- tukan gel) dan melting point (titik cair). Rancangan percobaan yang digunakan adalah Rancangan Acak Lengkap (RAL) faktorial dengan menggunakan 2 faktor perlakuan dan 3 kali ulangan. Perlakuan tersebut adalah konsentrasi asam cuka (A) dengan 3 taraf (0.5 persen, 1 dengan persen 3 taraf (1 jam, 2 jam, dan 3 jam). ...
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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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