Judul: Sintesis dan Pencirian Komposit Hidroksiapatit-Zink Oksida (HAp-ZnO) sebagai Biomaterial Antibakteri.
Abstrak: Hidroksiapatit (HAp) merupakan material yang lazim dimanfaatkan sebagai bahan implan tulang dan gigi. Penelitian berkembang untuk mencari dan menyintesis HAp dengan kemampuan antibakteri yang baik. Pada penelitian ini, senyawa HAp hasil sintesis dikompositkan dengan seng oksida (ZnO) untuk menghasilkan material antibakteri. HAp disintesis dengan metode presipitasi basah menggunakan cangkang tutut (Bellamya javanica) sebagai sumber kalsium. Pengompositan dengan senyawa ZnO dilakukan secara in situ. Persen kristalinitas material menurun dengan penambahan ZnO yang mengindikasikan bahwa substitusi ion Zn menghambat pertumbuhan kristal. Sifat antibakteri HAp dan komposit HAp-ZnO diuji terhadap Eschericia coli dan Staphylococcus aureus. Daya hambat terhadap bakteri uji meningkat pada HAp yang dikompositkan dengan ZnO. Komposit HAp-ZnO menunjukkan daya hambat yang lebih baik pada Eschericia coli yang merupakan bakteri Gram negatif.
Keyword: antibakteri, hidroksiapatit, komposit, zink oksida

Judul: Sintesis dan Pencirian Komposit Hidroksiapatit-ZnO-Kitosan Berporogen yang Berpotensi sebagai Implan Antibakteri
Abstrak: Kerusakan tulang dapat diperbaiki dengan menggunakan implan seperti hidroksiapatit (HAp), tetapi infeksi pascaoperasi dapat terjadi karena bakteri. Hal ini dapat diatasi dengan menambahkan bahan antibakteri, yaitu ZnO dan kitosan. Komposit HAp-ZnO-kitosan disintesis menggunakan metode presipitasi, kemudian larutan ZnO dan kitosan ditambahkan ke dalam suspensi HAp yang telah terbentuk. HAp berpori dibentuk dengan menambahkan pati singkong yang digunakan sebagai porogen. Berdasarkan literatur, ukuran pori yang terbentuk setelah penambahan pati singkong adalah 13.246.8 μm. Pola difraksi sinar-X pada sintesis HAp telah menunjukkan fase HAp dominan dan pada sintesis ZnO juga memperlihatkan fase ZnO yang lebih dominan. Spektrum inframerah transformasi Fourier pada HAp tanpa porogen memperlihatkan keberadaan pengotor berupa CO32-, sedangkan pada HAp porogen hanya terbentuk gugus penyusun senyawa HAp. Aktivitas antibakteri pada komposit HAp-ZnO-Kitosan 3% berpotensi menghambat pertumbuhan bakteri Escherichia coli.
Keyword: hidroksiapatit, kitosan, pati, porogen, ZnO

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: