Judul: Optimasi Proses Hidrolisis Serat Makanan (Dietary Fiber) Dari Limbah Mengkudu Dengan Metode Respon Permukaan
Abstrak: Produk serat dapat diperoleh dari serat mengkudu (Morinda citrifolia). Ampas yang basah bisa diolah lebih lanjut dengan cara hidrolisis dan pengeringan. Penelitian ini bertujuan untuk meningkatkan nilai tambah ampas mengkudu, mengetahui pengaruh waktu dan konsentrasi asam terhadap respon kadar selulosa, hemiselulosa, SDF dan kadar lignin dengan menggunakan rancangan percobaan RSM orde pertama. Hasil penelitian ini menunjukan bahwa waktu dan konsentrasi asam tidak memberi pengaruh yang nyata terhadap respon hemiselulosa, selulosa dan kadar SDF. Tetapi, kedua faktor ini memberikan pengaruh nyata untuk respon kadar lignin dengan nilai R2 sebesar 0.6489 yang artinya kedua faktor berpengaruh sebesar 64.89% terhadap kadar lignin, sedangkan sisanya 35.11% dipengaruhi oleh faktor lain yang belum diketahui.
Keyword: dietary fiber, RSM, SDF (soluble dietary fiber)

Judul: Optimasi hidrolisis hemiselulosa tandan kosong kelapa sawit dengan menggunakan asam sulfat encer
Abstrak: Tandan kosong kelapa sawit yang termasuk limbah lignoselulosik merupakan sumber selulosa yang belum banyak dimanfaatkan. Sebagai bahan organik polisakarida, pada dasarnya limbah tandan kosong kelapa sawit ini dapat diolah menjadi produk gula dengan cara hidrolisis. Tidak cukupnya luas permukaan untuk reaksi antara enzim dan substrat, struktur berkristal selulosa dan adanya lignin-hemiselulosa yang mengelilingi selulosa membuat hidrolisis ini sulit dilakukan. Selain itu ukuran pori yang cukup kecil sebelum biomassa mengalami perlakuan pendahuluan, juga membuat proses hidrolisis semakin sulit dilakukan. Oleh karena itu sebelum hidrolisis perlu dilakukan suatu perlakuan pendahuluan untuk mengurangi hambatan tersebut. Penelitian ini bertujuan untuk mencari kondisi optimum perlakuan pendahuluan hidrolisis hemiselulosa tandan kosong kelapa sawit dengan menggunakan asam sulfat encer. Rancangan percobaan yang digunakan adalah Response Surface Methodology dengan Rotatable Central Composite Design. Tiga faktor yang dipelajari meliputi kadar asam sulfat (0.3, 1, 2, 3 dan 3.7 persen), suhu hidrolisis (77, 85, 93, 98.5 dan 71.5°C) dan waktu hidrolisis (4.6, 6, 8, 10 dan 11.4 jam). Jumlah semua perlakuan adalah 20. Analisis yang dilakukan meliputi kadar air, kadar hemiselulosa, kadar selulosa dan kadar lignin untuk sisaan (residu), serta kadar xilosa, kadar arabinosa dan kadar glukosa untuk saringan (filtrat).
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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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