Judul: Crystallographic and Nanostructural Studies of Sr/Se Co-substituted Hydroxyapatite for Applications in Bone Graft and Anticancer Therapy
Abstrak: Sintesis berbagai biokeramik untuk aplikasi biomedis telah banyak dilakukan karena tingginya kasus cacat tulang. Salah satu sintesis yang sering dilakukan adalah sintesis hidroksiapatit (HA). Penelitian ini bertujuan menyintesis HA dengan memodifikasinya untuk mendapatkan sifat dan fungsi lain yang tidak terdapat dalam HA, seperti antikanker, dengan menambahkan ion Sr2+ dan SeO32- menggunakan metode presipitasi kimia basah. Hasil XRD menunjukkan bahwa puncak karakteristik konsisten dengan HA tanpa fase pengotor. Penambahan ion Sr2+ dan SeO32- menyebabkan penurunan ukuran kristal, kecuali pada sampel yang dikalsinasi pada suhu 1000 ?. Hasil FTIR menunjukkan keberadaan gugus OH- dan PO43- yang mengindikasikan komponen HA. Analisa EDS juga mengonfirmasi keberadaan unsur Sr dan Se dalam HA. Pengamatan TEM pada sampel yang dikalsinasi pada 1000 ? menunjukkan bentuk spherical dan peningkatan ukuran partikel seiring bertambahnya ion substitusi akibat peningkatan pertumbuhan kristal pada suhu tinggi. Analisa struktur kristal melalui TEM juga dilakukan untuk mengonfirmasi hasil XRD. Kata kunci: hidroksiapatit, kristal, partikel
Keyword: hidroksiapatit

Judul: Kajian Komposisi Hidroksiapatit yang Disintesis dengan Metode Hidrotermal
Abstrak: Accidents are the biggest factors causing injuries all over the world, and generally resulted is the form of stress fracture. The increase in the study on the handling procedures of this issue, the healing processes of bone injury are getting better one of the procedures used by many people’s by using biomaterials. Bone biomaterials commonly used are bioceramics. One of the types of bioceramics is hydroxyapatite. In this research, the synthesis of hydroxyapatite is reported. Synthesis of hydroxyapatite was done by hydrothermal method at a temperature of 150, 200, 250, and 300 oC for 3 hours and sintered at a temperature of 900 oC. At 200 oC synthesized hydroxyapatite was given a further treatment. At a temperature of 200 oC synthesizing procedure was back to the time variation, i.e. 1 hour and 5 hours. The results of the characterization of Fourier Transform Infrared Spectroscopy (FTIR) for all the samples showed hydroxyapatite phase at a temperature of 200 oC. The results of the characterization of Atomic Absorption Spectroscopy (AAS) for all samples showed hydroxyapatite formed is not pure because there are also some other phases.
Keyword: Hydrothermal, Hydroxyapatite, Fourier Transform Infrared Spectroscopy, Atomic Absorption Spectroscopy

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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