Judul: Optimisasi ekstrasi cair-cair senyawa aktif daun laban abang (Aglaia elliptica)
Abstrak: Laban abang (Aglaia elliptica) merupakan salah satu jenis tanaman famili Meliaceae yang banyak diteliti aktivitas kandungan senyawa aktifnya terhadap sel kanker dan sebagai insektisida botani. Dalam penelitian ini dilakukan optimisasi ekstraksi cair-cair menggunakan etil asetat dengan nisbah bahan baku-pelarut 1:1, 1:2, 1:3 selama 10, 20, dan 30 menit dengan ekstraksi satu, dua, dan tiga kali untuk mengetahui kondisi ekstraksi senyawa aktif yang paling baik digunakan.
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Judul: Optimisasi Ekstraksi Cair-Cair Fraksi Etanol Daun Dandang Gendis (Clinacanthus nutans)
Abstrak: Dandang gendis (Clinacanthus nutans) is a herb which contains antimalaria and larvacide bioactive compounds. In this study, the dried leaf powder was macerated with ethanol and then partitioned with n-hexane. The resulting ethanol extract was then partitioned again with ethyl acetate and this liquid-liquid extraction procedure was the subject of the optimization. Sample to solvent ratio (1:2, 1:3, and 1:4 (mL/mL), extraction temperature (30, 40, and 50 °C); and extraction repetition (1, 2, and 3 times) variations effect were studied. The bioactivity of the extracts were tested with brine shrimp lethality test (BSLT) using Artemia salina. The BSLT result of the 11th extract showed the optimum LC50 value (59.15 mg/L). This extract was obtained from the extraction procedure using 1:4 (mL/mL) sample to solvent ratio, 40 °C temperature, and 3 times repetition. From the Minitab 15 computation results were predicted that the optimum condition is achieved at 1:3.88 – 1:4.00 (mL/mL) sample to solvent ratio, 4.61 – 49.99 °C extraction temperature, and 3 times extraction repetition with LC50 170.19 mg/L. The phytochemistry test results showed that the 11th extract contains alkaloids, flavonoids, saponins, and steroids.
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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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