MAKARA Journal of Technology
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Microgrid Development Using A Grid Tie Inverter
Get PDFThe use of renewable energy sources (RES), especially photovoltaic (PV), to meet the demand of electrical energy has been getting a great deal of attention as an alternative solution to electrical energy deficit problems. RES are being applied in power systems in a variety of configurations including microgrid systems. One of the characteristics of a microgrid is capability to supplying power to grid when there is an excess power to supply local load. This research examines the chances of saving power consumption from grid using power converters grid tie inverter (GTI) in a microgrid configuration. The test is done by using a zero load and power distribution methods. Test results show grid tie GTI capable of supplying electrical power to grid up to 98% of the input power converter. In the microgrid configuration power usage from grid can be reduced up to 91%, which should be supplied from the grid to load.Keywords: architecture of microgrid, grid tie inverter (GTI), microgrid, Photovoltaic (PV
Semiconductor Thermal Neutron Detector
Get PDFThe CdTe and GaN detector with a Gd converter have been developed and investigated as a neutron detector for neutron imaging. The fabricated Gd/CdTe detector with the 25 mm thick Gd was designed on the basis of simulation results of thermal neutron detection efficiency and spatial resolution. The Gd/CdTe detector shows the detection of neutron capture gamma ray emission in the 155Gd(n, g)156Gd, 157Gd(n, g)158Gd and 113Cd(n, g)114Cd reactions and characteristic X-ray emissions due to conversion-electrons generated inside the Gd film. The observed efficient thermal neutron detection with the Gd/CdTe detector shows its promise in neutron radiography application. Moreover, a BGaN detector has also investigated to separate neutron signal from gamma-ray clearly. Keywords: detector, neutron, semiconductor, therma
Recycling Roof Tile Waste Material for Wall Cover Tiles
Get PDFPrior research on roof tile waste treatment has attempted to find the appropriate technology to reuse old roof tile waste by create wall cladding materials from it. Through exploration and experimentation, a treatment method has been discovered to transform the tile fragments into artificial stone that resembles the shape of coral. This baked clay artificial stone material is then processed as a decorative element for vertical surfaces that are not load-bearing, such as on the interior and exterior walls of a building. Before applying the fragments as wall tiles, several steps must be taken: 1) Blunting, which changes the look of tile fragments using a machine created specifically to blunt the roof-tile fragment edges, 2) Closing the pores of the blunted fragments as a finishing step that can be done with a transparent coat or a solid color of paint, 3) Planting the transformed roof-tile fragments on a prepared tile body made of concrete. In this study, the second phase is done using the method of ceramics glazing at a temperature of 700 °C. The finishing step is the strength of this product because it produces a rich color artificial pebble.Keywords: artificial coral, blunting, recycling, roof-tile waste, wall claddin
Surface Treatment of Fly Ash for Improving the Tensile Strength of Fly Ash/Unsaturated Polyester Composites
Get PDFThe paper presents the surface treatment of fly ashes using acid and alkali solution on the tensile strength of the fly ash/unsaturated polyester (UP) composites. Sulfuric acid (H2SO4), hydrofluoric acid (HF) and sodium hydroxide (NaOH) solution with concentration of 0%, 5%, 10%, 15%, and 20% (by weight) were used for surface treatment of fly ashes. Generally, the tensile strength of the treated fly-ash/UP composites shows a significant increase compared to the untreated fly ash. Of all surface treatments studied, the optimum tensile strength was obtained at a concentration of 10%. At this concentration, at a fly ash content of 30% (weight), the surface treatment using NaOH gave the highest tensile strength, approximately 18.69 MPa, or increased about 91% compared to the untreated fly ash. The morphology of fracture surfaces were evaluated using a scanning electron microscope (SEM). The fracture surfaces of the treated fly ash composite were rougher than that of the untreated fly ash indicating the improvement of the fly ashes-UP interaction.Keywords: composites, fly ash, surface treatment, tensile strength, unsaturated polyeste
Synthesis of Tungsten Oxide Nanowires onto ITO Glass Using T-CVD
Get PDFTungsten oxide is an n-type semiconductor with interesting physical and chemical properties that make it suitable for various technological applications. Tungsten oxide nanowires were synthesized not only at low temperature but also without the use of any catalysts. The tungsten oxide nanowires were synthesized at 550 °C with tungsten layers onto the ITO glass using thermal chemical vapor deposition (T-CVD). The SEM image shows that the tungsten oxide nanowires are effectively grown with the 200 nm tungsten film. The Raman spectra shoulder at ~690 cm-1 proves the synthesized of tungsten oxide nanowires.Keywords: ITO glass, thermal chemical vapor deposition, Tungsten oxide nanowire
The Effect Zeolite Addition in Natural Rubber Polypropylene Composite on Mechanical, Structure, and Thermal Characteristics
Get PDFThis study was conducted to determine the effect of zeolite as filler on mechanical properties, and thermal structure blends of natural rubber and polypropylene (NR/PP). In this study, NR/PP/PP-g-MA blends was filled uncalcined zeolite and calcined zeolite at different weight percent of the 2, 4, and 6%. Samples were characterized to determine the tensile strength, fracture elongation and Young's modulus. Structure of the samples was investigated using XRD method and thermal characteristics were analyzed using DTA/TGA technique. The results obtained for tensile strength showed a significant influence with the addition zeolite of the NR/PP blends at 2% by weight of the composition (8 MPa) and decreased with increasing zeolite composition uncalcined zeolite or calcined zeolite. At 2% to 6% by weight of an increase in Young's modulus, for which uncalcined zeolite function more effectively than the calcined zeolite. On the other hand, the addition of uncalcined zeolite and calcined zeolite did not result in decreased fracture elongation. The XRD analysis zeolite indicate the existence of amorphous phase and crystalline mineral type mordenite (CaAl2Si10O24.7 H2O). In general, cristality of samples filled with calcined zeolite slightly higher than the uncalcined zeolite at the same amount and intercalation occurs between the zeolite matrix NR/PP. Thermal analysis showed that the samples are filled with calcined zeolite has a thermal resistance higher than the uncalcined zeolite, the melting point NR/PP 165.0 °C with the addition of 6 wt% zeolite melting point to 186.7 °CKeywords: mechanical, natural rubber, structure, thermal, zeolit
The Effect of Pressing Temperature and Time on the Quality of Particle Board Made from Jatropha Fruit Hulls Treated in Acidic Condition
Get PDFThe high of pH of jatropha fruit hulls causes the negative properties of particleboard made from this material. Adjusting the particle acidity and pressing conditions (temperature and time) is among the technical modifications available to improve this particleboard’s properties. Particle acidity has been adjusted in a previous research project, and immersing the particles in acetic acid was found to be the best treatment in this preliminary research. In order to improve the particleboard’s properties, an experiment was conducted to determine the best pressing temperature and time. The objective of the research was to evaluate the influence of pressing temperature and time on the physical and mechanical properties of the board. Jatropha fruit hulls were immersed in 1% acetic acid solution for 24 hours. UF resin was used as the adhesive in the amount of 10%. The pressing temperatures and times used in this research were 110 °C, 120 °C, and 130 °C for 8 and 10 minutes, respectively. The particleboards were tested to determine their physical and mechanical properties according to JIS A 5908-2003. The result showed that pressing at 130 °C for 10 minutes resulted in the best physical and mechanical properties. Increasing the pressing temperature at a constant time or increasing the pressing time at a constant temperature caused the particleboard to exhibit decreased water absorption. The thickness swelling and modulus of elasticity (MOE) of the particleboard did not fulfil JIS A 5908-2003.Keywords: jatropha fruit hulls, particleboard, pressing temperature and tim
Surface Modification of Graphite-Encapsulated Iron Compound Magnetic Nanoparticles by Radio Frequency Inductively-Coupled Plasma for Biomolecules Immobilization
No full textWe proposed the graphite-encapsulated iron compound magnetic nanoparticles as a candidate of nanomaterial due to their potential properties on physical, chemical and biological fields. This study was performed in three steps, starting from the nanoparticle fabrication, nanoparticle surface modification by plasma treatment, leading to biomolecules immobilization for testing the treated nanoparticles capabilities. After the plasma treatment, the surface of the outmost graphene layer is successfully covered by nitrogen-containing groups definitively assigned by XPS spectra and the STEM-EDS elemental mapping. The nitrogen-containing groups formed during the post-treatment plasma selectively attached on the outmost of graphene layer. The inner structure of inner graphene layer and the iron core are still found in stable condition which means that the applied plasma condition allows the efficient covalent functionalization of nitrogen-containing group to the surface particles without give any destruction. The results shows the highest values of N/C atomic ratio of 5.4% is obtained by applying 10 min of Ar plasma pre-treatment and 2 min of NH3 plasma post-treatment conducted in RF power of 80W and gas pressure of 50 Pa. Finally, in the biomolecules section, it is found that the primary amino groups grafted after Ar plasma pre-treatment followed by NH3 plasma post-treatment appeared to play an important role in dextran immobilization. The primary amines provide a high selective reaction between aldehyde group of oxidized dextran and amino groups of treated nanoparticles, hence the covalent immobilization was successfully achieved. The dextran immobilization was confirmed by XPS and HR-TEM analysis followed by amino group derivatization using TFBA. The deconvoluted peak at ~398.6 eV (C=N) (as an evidence for Schiff-base linkages between dextran and amino groups on the treated nanoparticles) increased with the increasing of the dextran concentration. This result is consistent with the decrease of free amino group percentage remaining on the nanoparticles surfaces which was evidenced when the dextran concentration increased. High magnification images obtained by HR-TEM allowed the visual observations of the differences between surface morphology of nanoparticles before and after dextran immobilization.Keywords: biomolecule immobilization, magnetic nanoparticles, surface modificatio
PHYSICAL CHARACTERIZATION AND DESULFURIZATION OF BIOBRIQUETTE USING CALCIUM-BASED ADSORBENT
Get PDFCombustion of coal and co-combustion of their co-fuel contribute to gas emissions. Among the gas emissions are SOx, NOx, CO and CO2. Introduction of calcium based adsorbent is addressed to absorb SO2 that release to the atmosphere during the combustion process. Objective of the research is at first to observe the physical characteristics of biobriquettesas a function of briquette compositions (coal to palm kernel shell ratios) and Ca/S ratios (Ca in adsorbent and S in briquette) using a natural adsorbent (shellfish waste). The second objective is to investigate desulfurizationcharacteristics as a function of Ca/S ratios and desulfurization temperatures at coal to palm kernel shell ratio of 90:10 (wt %). Ratios of coal to palm kernel shell in this study are 90:10, 80:20, 70:30, 60:40 and 50:50; and Ca/S ratios are 1:1, 1.25:1, 1.5:1, 1.75:1 and 2:1. Binding agent used is the mixture of Jatropha curcas seeds and starch as much as 10% (wt). It was found that introducing the palm kernel shell and adsorbents in the coal briquette affect the water resistant and compressive strength. The highest water resistance and compressive strength were 5,165 second and 34 kg/cm2, respectively. The lowest SO2 level found in this study was 1 ppm for all Ca/S ratios, except for 1:1.Keywords: bio-briquettes, calcium-based adsorbent, Ca/S ratio, coal/palm kernel shell ratio, desulfurizatio
THE EFFECTIVENESS OF ANAEROBIC BAFFLED REACTOR AND ROTATING BIOLOGICAL CONTACTOR IN BATIK WASTEWATER TREATMENT
No full textBatik is one of popular arts of Indonesia. The batik industries in Sragen, Central Java, are prepared to compete in global market. In order to realize that objective, batik products should fulfill some qualifications, one of which is “environmental friendliness”. As batik production is usually generating wastewater which pollutes the environment, the technology of wastewater treatment should be developed to solve the problem. This preliminary study has been done to assess the effectiveness of anaerobic baffled reactor (ABR) and rotating biological contactor (RBC) in batik wastewater treatment. In 40 days of treatment period, the ABR performance in reducing pollutants showed an effectiveness up to 75%, whereas RBC effectiveness was in the range of 15-57%. Concerning the quality standard of wastewater, the wastewater treatment system showed a good performance to decrease pH, whereas the COD was still high. Further optimization, then, is needed to improve the quality of effluent.Keywords: anaerobic baffled reactor, batik, effectiveness, rotating biological contactor, wastewate