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Diffusion flame spray drying has become promising method in nanoparticles synthesis giving several advantages and low operation cost. In order to scale up the process which needs high experimentation time and cost, Computational Fluid Dynamics (CFD) by Ansys Fluent 15.0 software has been used. Combustion characteristic in diffusion flame reactor may affects particle size distribution. This study aims to observe influence of fuel type to combustion characteristic in the reactor. Large Eddy Simulation (LES) and non-premixed combustion model are selected for the turbulence and combustion model respectively. Methane, propane, and LPG in 0.5 L/min were used as type of fuel. While the oxidizer is air with 200% excess of O2. Simulation result shown that the maximum temperature was obtained from propane-air combustion in 2268 K. However, the stable temperature contour was achieved by methane-air combustion.

Antioxidant compounds from mangosteen pericarps have been extracted with low-transition-temperature mixture (LTTM) assisted hydrothermal method. Extracted antioxidant compounds were determined as xanthone and total phenolic compounds. The effects of temperature, concentration of LTTM, and sonication pretreatment on the recovery of xanthone and total phenolic compounds were investigated. Extraction were carried out in a batch extractor at various temperatures (120 – 160°C), concentrations of LTTM (0.1 – 0.3 mg/mL), and sonication pretreatments (0 – 10 min). LTTM used for extraction was consisted of citric acid as hydrogen bond donor and alanine as hydrogen bond acceptor. Xanthone and total phenolic compounds were analyzed by spectrophotometer. In order to determine the effect of extraction condition on the antioxidant efficiency of the extract, the antioxidant efficiency of extract were analyzed by DPPH assay method. Based on the result, the recovery of xanthone increased as increasing temperature and concentration of LTTM. Inversely, the recovery of total phenolic compounds decreased as increasing temperature. The sonication pretreatment had significantly effect on the recovery of both xanthone and total phenolic compounds, however the optimum condition of sonication pretreatment was at 5 min. The antioxidant efficiency of the extract was affected by the extraction condition, and the highest antioxidant efficiency was 1.395 obtained at temperature of 120°C, LTTM concentration of 0.3 mg/mL, and sonication time of 5 min.Antioxidant compounds from mangosteen pericarps have been extracted with low-transition-temperature mixture (LTTM) assisted hydrothermal method. Extracted antioxidant compounds were determined as xanthone and total phenolic compounds. The effects of temperature, concentration of LTTM, and sonication pretreatment on the recovery of xanthone and total phenolic compounds were investigated. Extraction were carried out in a batch extractor at various temperatures (120 – 160°C), concentrations of LTTM (0.1 – 0.3 mg/mL), and sonication pretreatments (0 – 10 min). LTTM used for extraction was consisted of citric acid as hydrogen bond donor and alanine as hydrogen bond acceptor. Xanthone and total phenolic compounds were analyzed by spectrophotometer. In order to determine the effect of extraction condition on the antioxidant efficiency of the extract, the antioxidant efficiency of extract were analyzed by DPPH assay method. Based on the result, the recovery of xanthone increased as increasing temperature and conc...

Coconut husk wastes are abundantly available in Indonesia. It has a potential to be used into alternative renewable energy sources such as hydrogen using enzymatic hydrolysis followed by a fermentation process. Unfortunately, enzymatic hydrolysis is hampered by the complex structure of lignocellulose, so the cellulose component is hard to degrade. In this study, Combined Subcritical Water (SCW) and enzymatic hydrolysis are applied to enhance fermentable, thereby reducing production of sugar from coconut husk. There were two steps in this study, the first step was coconut husk pretreated by SCW in batch reactor at 80 bar and 150-200°C for 60 minutes reaction time. Secondly, solid fraction from the results of SCW was hydrolyzed using the mixture of pure cellulose and xylanase enzymes. Analysis was conducted on untreated and SCW-treated by gravimetric assay, liquid fraction after SCW and solid fraction after enzymatic hydrolysis using DNS assay. The maximum yield of reducing sugar (including xylose, arabinos...

ZnO-SiO2 nanocomposite particles were prepared by sonochemical method under continuous ultrasound irradiation for an hour. Zinc nitrate and sodium silicate were used as zinc oxide and silica sources, respectively. Silica concentration was varied to investigate the effect of silica on the characteristics of the generated composite particles and they were also compared to ZnO particles. Morphology, crystallinity, chemical bonding analysis, photoluminescence spectra, and photocatalytic activity were characterized by scanning electron microscopy (SEM), X-Ray diffraction, Fourier Transform Infrared (FTIR), luminescence spectrophotometer, and UV-Vis spectrophotometer, respectively. Nanorod structures were observed for pure ZnO, ZnO-SiO2 particles with 250 ppm and 750 ppm silica addition during synthesis. Spherical agglomerated particles were found for particle with 0.1 M silica addition. The crystalline size and photocalytic activity decreased with the silica addition. A strongest chemical bonding for ZnO and SiO2 was also observed for particle with 0.1 M silica addition based on FTIR spectra. However, the highest photoluminescence emission by excitation wavelength at 250 nm, was observed for ZnO-SiO2 particles with 750 ppm silica addition with emission peak at 515 nm wavelength.

Agitated tank with side entering mixer is commonly used in industrial processes. This study aims to determine the flow pattern and mixing time as function of impeller diameter, impeller rotation speed, and number of impeller blades. The single phase system with water as working fluid inside the stirred tank was modeled using the combination of multiple reference frame (MRF) and k-e turbulence model and calculated using the computational fluid dynamics (CFD) method. The size of stirred tank is 0.4 m and 0.6 m for diameter and height, respectively. The agitated tank was equipped with 45° inclined blade turbine impeller. Four different impeller in diameter and number of blades have been elucidated under various operating condition of impeller rotation speed from l00 rpm until 400 rpm. The simulation results showed that the flow pattern formed is single-loop circulation and vortex, depended on stirred tank configuration and operating conditions. Besides, there were variations in flow patterns change over time...

The advantages of Pulse Combustion process than the normal combustion was presented in this research. Reviews of phenomena and mechanisms of pulse combustion was compared with normal combustion which air or fuel was streamed continuously. Multi-dimensional simulation of turbulent flow in the combustion chamber was performed by computational fluid dynamics (CFD) with ANSYS FLUENT 15.0 software. 2D illustration axis symmetry with turbulence models k-turbulence combustion reaction using Eddy Dissipation models was used to analyze this process that has a high turbulence. Propane was used as the type of fuel with flow rate of 15 L/min. the flowrate 375 L/min of air was used as oxidizer, to meet the needs of propane and oxygen ratio of 1: 5. Based on the result, pulse combustion has higher combustion efficiency than normal combustion. This result was judged from fewer fuel that was not burned. Another advantage of using pulse combustion was the back flow of tailpipe that decrease the number of unburned reactant...

So far, most of the data published by Statistics Indonesia (BPS) as data providers for national statistics are still limited to the district level. Less sufficient sample size for smaller area levels to make the measurement of poverty indicators with direct estimation produced high standard error. Therefore, the analysis based on it is unreliable. To solve this problem, the estimation method which can provide a better accuracy by combining survey data and other auxiliary data is required. One method often used for the estimation is the Small Area Estimation (SAE). There are many methods used in SAE, one of them is Empirical Best Linear Unbiased Prediction (EBLUP). EBLUP method of maximum likelihood (ML) procedures does not consider the loss of degrees of freedom due to estimating β with β ^. This drawback motivates the use of the restricted maximum likelihood (REML) procedure. This paper proposed EBLUP with REML procedure for estimating poverty indicators by modeling the average of household expenditures ...