Judul: Mempelajari Cara Pembuatan Biogas Melalui Proses "Rumen Derived Anaerobic Digestion" (Rudad)
Abstrak: Bahan-bahan organik alami seperti kotoran , limbah perkebunan, limbah pertanian, limbah industri dan bahan pertanian lainnya mengandung senyawa yang sukar atau tidak terde- - gradasi. Dalam biogas cara konvensional ha1 ini menjadi kendala yang belum terpecahkan sehingga efisiensi perombakan (degradability) terhadap bahan-bahan tersebut masih rendah. Cara yang dilakukan dalam penelitian ini adalah sistem pembuatan biogas melalui proses "Rumen Derived Anaerobic Digestion" atau disebut dengan proses "RUDAD". Kelebihan dari cara ini adalah penggunaan mikroba rumen ruminansia yang lebih beragam dibandingkan dengan mikroba yang terdapat dalam kotoran hewan. Mikroba yang terlibat dalam proses perombakan meliputi berbagai jenis bakteri, protozoa siliata (tak ditemukan secara alami di tempat lain) dan kapang fikomisetes.
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Judul: Desain proses produksi biogas dari jerami padi dan sampah pasar dengan sistem fermentasi media padat
Abstrak: The purpose of this research were to design of fermentation process for converting rice straw and organic waste from traditional market to produce biogas, to know influence of aeration, to obtain the best feed addition in fermentation, and to obtain characteristic of product (digestate and leachate) from fermentation process. Beef cattle manure as substrate was inoculated to anaerobic digestion. Laboratory experiments using 10 l digester were performed in batch mode. The operating temperature was mesophilic condition (35-40oC). Fermentation rice straw with feed addition 75% new feeds and 25% digestate could produce 42.2 l gas/kg VS higher than fermentation rice straw from all new feeds (28.1 l gas/kg VS) and fermentation from 50% new feeds and 50% digestate (15.8 l gas/kg VS). While fermentation waste market from all new feeds could produce 51.8 l gas/kg VS higher than fermentation with feed addition 75% new feeds and 25% digestate (39.7 l gas/kg VS) and fermentation from 50% new feeds and 50% digestate (31.1 l gas/kg VS). The cumulative volume of biogas produced was used to measure the biodigester performance. The research gave the kinetic parameters of biogas production for rice straw i.e. biogas production rate constants (Rmax), maximum biogas production (A), and minimum time to produce biogas (λ) were 1.37-2.07 (l/kg VS.day), 15.82-42.25 (l/kgVS), and 0.4-2.0 days, respectively. While the organic waste from market gave the kinetic parameters U, A, and λ of 1.58-3.55 (l/kgVS.day), 31.09-51.84 (l/kgVS), and 0.2-1.2 days, respectively.
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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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