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"Rice husk is one of themost abundant biomass wastes in Indonesia. One way to convert it into analternative source of energy is biomass gasification. This is a thermochemicalprocess which converts biomass feedstock into fuel gas or chemical feedstockgas (producer gas). The gasification type which is developed in this study isfixed bed downdraft type due to its low tar content and compatibility inmicroscale implementation. One major problem with the implemented biomassgasification reactor was ruggedness of the partial oxidation process due to theabsence of air in the reactor?s middle section, which consequently affected thepyrolysis zone. Several experiments were conducted previously using coconutshells and rice husks as solid feedstock, where an equivalence ratio (ER) of0.4 was obtained. Therefore, in order to optimize the pyrolysis zone, themodification conducted involves adding a circular air intake into the gasifier.Experiments were conducted in a pyrolysis temperature range of 300?700oCwith ER variation of 0.19, 0.24, 0.27 and 0.31. The results show that a goodquality producer gas is produced at an ER value of 0.24. This value shows apromising result because the ER value of biomass gasification standard is 0.25."

"Rice husk is one of the most abundant biomass wastes in Indonesia. One way to convert it into an alternative source of energy is biomass gasification. This is a thermochemical process which converts biomass feedstock into fuel gas or chemical feedstock gas (producer gas). The gasification type which is developed in this study is fixed bed downdraft type due to its low tar content and compatibility in microscale implementation. One major problem with the implemented biomass gasification reactor was ruggedness of the partial oxidation process due to the absence of air in the reactor’s middle section, which consequently affected the pyrolysis zone. Several experiments were conducted previously using coconut shells and rice husks as solid feedstock, where an equivalence ratio (ER) of 0.4 was obtained. Therefore, in order to optimize the pyrolysis zone, the modification conducted involves adding a circular air intake into the gasifier. Experiments were conducted in a pyrolysis temperature range of 300–700oC with ER variation of 0.19, 0.24, 0.27 and 0.31. The results show that a good quality producer gas is produced at an ER value of 0.24. This value shows a promising result because the ER value of biomass gasification standard is 0.25."

"Sekam padi menjadi salah satu limbah biomassa yang melimpah di Indonesia. Salah satu cara konversi sekam padi menjadi energi alternatif adalah gasifikasi biomassa. Gasifikasi biomassa merupakan proses termokimia untuk mengonversi bahan baku biomassa menjadi bahan bakar gas atau bahan baku gas kimia (producer gas). Gasifikasi biomassa yang tengah dikembangkan adalah tipe fixed bed downdraft. Tipe ini dipilih karena hasil tar yang sedikit dan cocok untuk skala mikro. Salah satu permasalahan dari desain reaktor gasifikasi biomassa yang digunakan adalah kurang meratanya proses oksidasi parsial, sehingga memengaruhi zona pirolisis. Proses oksidasi parsial yang kurang merata ini disebabkan oleh pada bagian tengah reaktor tidak tersuplai udara dengan merata. Pada penelitian sebelumnya yang menggunakan cangkang kelapa dan sekam padi, equivalence ratio (ER) untuk proses gasifikasi adalah 0,4. Maka untuk melakukan optimasi zona pirolisis, dilakukan modifikasi air intake dengan menambahkan circular air intake. Setelah dilakukan modifikasi dan pengujian pada temperatur operasional zona pirolisis 300-700 oC, dengan melakukan variasi ER yaitu 0,19, 0,24, 0,27, dan 0,31, akhirnya didapatkan ER paling optimal untuk menghasilkan producer gas dengan kualitas baik yaitu pada ER 0,24. ER paling optimal ini sesuai dengan standar gasifikasi biomassa, yaitu sekitar 0,25.

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Rice husks into one of abundant biomass waste in Indonesia. One way of converting rice husks into alternative energy is biomass gasification. Biomass gasification is a thermochemical process to convert biomass feedstock into fuel gas or chemical feedstock gas (producer gas). Gasification of biomass that is being developed is a type of fixed bed downdraft. This type is chosen because the results were a little tar and suitable for the micro scale. One of the problems of biomass gasification reactor design used is less inequality partial oxidation process, thus affecting the pyrolysis zone. Partial oxidation process is uneven due to the middle part of the reactor is not well supplied with evenly distributed air.

Previous studies using coconut shells and rice husks, equivalence ratio (ER) for the gasification process is 0.4. Then to optimize the pyrolysis zone, be modified by adding circular air intake. After the modification and testing the operating temperature pyrolysis zone of 300-700 °C, by doing ER variation is 0.19, 0.24, 0.27, and 0.31, eventually obtained the most optimal ER to produce gas producer with good quality, namely the ER 0.24. This ER is the most optimized according to the standard gasification of biomass, which is about 0.25."

"Agricultural waste hasincreased colossally with development in agricultural production causing environmentalnuisance and degradation. Utilization of coconut husks, one of such type of waste, as a biosorbent for polluted surface water treatment, wasconsidered in this study. Polluted surface water was gently passed through twosimilar columns loaded with 100 and 200 g of coconut husk char respectively.The treated water samples collected after 30, 60, 90, 120 and 150 mins wereexamined for SO42-, NO3- and PO43-ions concentration. Removal efficiency for SO42-, NO3-and PO43- ions on 100 g coconut husk char after 150mins detention time were 70, 78 and 91% respectively. Freundlich isotherm modelgave a better description of the data (R2 > 0.96). Sorption datawas well described by second order pseudo kinetics (R2 >0.85). An amount of 100 g of the biosorbenthas astrong affinity for these types of ion removal in contaminated water. Coconut huskchar as a biosorbentis a panacea to significant concentrations of polyatomic ions in polluted surface water."

"Due to criticalenvironmental issues, increasing future energy supplies and decreasing reservedenergy resources are currently the subject of comprehensive research. The useof biomass as a renewable energy resource may be helpful in solving currentenergy shortfalls, particularly for countries that have abundant biomassresources. In this study, pyrolysis of coal, Acacia Mangium wood, and their respective blend samples wereinvestigated using proximate analysis and Thermogravimetric (TG?DTG). A mixtureof coal and A. Mangium wood with aweight ratio 100:0, 90:10, 50:50, 10:90, and 0:100, were used andnon-isothermal conditions at a constant heating rate of 5, 15, and 30°C/minwere applied. Thermal evolution profile analysis of the pyrolysis processconfirms that the reactivity of the fuel increased with the increasingproportion of the biomass in the fuel. The reactivity and maximum temperaturesincreased with the increasing heating rates. Proximate analysis showed thepotential of biomass of A. Mangiumwood to be used as a mixture with coal in terms of low ash and high volatilematter content."

"Fluorine-doped tin oxide (FTO) is one of the conductive glasses that have strategic functions in various important applications, including dye-sensitized solar cell (DSSC). In the current work, the effects of deposition time (5, 10, 20, 30, and 40 minutes) upon the fabrication process of FTO thin film using spray pyrolysis technique with modified ultrasonic nebulizer has been studied in regard to its microstructural, optical, crystallinity, and resistivity characteristics. The variation was also performed by comparing the pure tin chloride precursor and the solution that was doped with fluor (F) at 2 wt% in order to see the doping effect on the properties of thin film. The thin films were characterized using x-ray diffraction (XRD), scanning electron microscope (SEM), ultraviolet-visible (UV-Vis) spectroscopy, and digital multimeter. On the basis of current investigation, it has been found that the best FTO was obtained through the pyrolysis technique of 20-minute deposition time, providing optical transmittance of 74%, a band gap energy (Eg) of 3.85 eV and sheet resistance (Rs) of 7.99 Ω/sq. The fabricated FTO in the present work is promising for further development as conducting glass for dye-sensitized solar cell (DSSC)."

"Transparent conducting oxide (TCO) glasses play an important role invarious technology, including dye sensitized solar cells. One of the mostcommonly used glass is indium tin oxide (ITO) glass, which is expensive.Therefore, the mainpurpose of this research was to determine if ITO glass can be replaced withfluorine-doped tin oxide (FTO) glass,which is easier and more economic to manufacture. For this purpose, a tinchloride dehydrate (SnCl2.2H2O)precursor was doped with ammoniumfluoride (NH4F) using asol-gel method and spray pyrolysis technique toinvestigate the fabrication process for conductiveglass. NH4F wasdoped at a ratio of 2 wt% in the SnCl2.2H2O precursor atvarying deposition times (10, 20, and 30 minutes) and substrate temperatures(250, 300, and 350°C). Theresults revealed that longer deposition times created thicker glass layers withreduced electrical resistivity. The highest opticaltransmittance was 75.5% and the lowest resistivitywas 3.32´10-5 Ω.cm,obtained from FTO glasssubjected to a 20-minute deposition time at deposition temperature of 300oC."

"The fixed jacket isstill the most common offshore structure used for drilling and oil production.The structure consists of tubular members interconnected to form athree-dimensional space frame, which can be categorized into a columnstructure. The structure usually has four to eight legs that are battered toachieve stability against axial compressive loads and toppling due to waveloads. The configuration of a typical member on the jacket structure hassignificant influence on buckling and fatigue strength. Horizontal and diagonalbraces play an important role in resisting the axial compression and wave loadon the global structure. Thispaper discusses the effect of symmetrical and asymmetrical configuration shapesin buckling and fatigue strength analysis on two types of fixed jacket offshoreplatforms. The axial compressive and lateral (wave) loads were considered andapplied to both structures. The material and dimensions of the two structureswere assumed to be constant and homogenous. Crack extension and corrosion werenot considered. To assess the buckling and fatigue strength of thesestructures, due to the symmetrical and asymmetrical configuration shape, thefinite element method (FEM) was adopted. Buckling analysis was performed onthese structures by taking two-dimensional planes into consideration to obtainthe critical buckling load for the local plane; fatigue life analysis was thencalculated to produce the fatigue life of those structures. The result obtainedby FEM was compared with the analytical solution for the critical bucklingload. The stress-strain curve was also applied to show the difference betweensymmetrical and asymmetrical shapes. For fatigue life analysis, the procedureof the response amplitude operator was applied."

"As an initial analysis,numerical simulation has more advantages in saving time and costs regarding experiments. For example, variations in flowconditions and geometry can be adjusted easily to obtain results. Computationalfluid dynamics (CFD) methods, suchas the k-ε model, renormalizationgroup (RNG) k-ε model and reynolds stress model (RSM), are widely used toconduct research on differentobjects and conditions. Choosing the appropriate model helps produce and developconstant values.Modeling studies as appropriate, i.e., in the turbulent flow simulation in the windtunnel, isdone to get a more accurate result. This study was conducted by comparing the results ofthe simulation k-ε model, RNG k-ε model and RSM, which is validated by the testresults. The air had adensity of 1,205 kg/m3, a viscosity of 4×10-5 m2/sand a normal speed of 6 m/s. By comparing the simulation results of the k-ε model, RNG k-ε model and RSM, which isvalidated by the test results, the third turbulencemodel provided good results to predict the distribution of speedand pressure of the fluid flow in the wind tunnel. As for predicting theturbulent kinetic energy, turbulent dissipation rate and turbulent effectiveviscosity, the k-εmodel was effectivelyused with comparable results to the RSM models."