IPTEK The Journal of Engineering
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The Influence of Multi-frequency Current Injection in Image Reconstruction for Two-Dimensional High-Speed Electrical Impedance Tomography (EIT)
Get PDFThe image reconstruction for two-dimensional high-speed Electrical Impedance Tomography (EIT) has been successfully studied with multi-frequency current injection. The aim of this study is to get the best image reconstruction under the influence of multi-frequency current injection of this EIT system. In this method, we used current injection at 1 mA with varies of frequency in the range 10 to 50 kHz injected at the practical phantoms with 16 electrodes. Polyvinyl chloride (PVC) cylinder was put in the practical phantom as the anomaly. Then, The boundary voltage of the practical phantom was measured by the voltage measurement circuit. After that, it processed in the computer with Gauss-Newton Algorithm to got image reconstruction. The result showed that the best image reconstruction was achieved at 10 kHz of frequency current injection. The best image reconstruction had more accuracy of shape, position and electrical properties of an anomaly in boundary phantom than another image reconstruction result
Relocation Of Earthquake Hypocenter In The Flores Region Using Hypo71
Get PDFFlores is one of the seismically high activity zones of Indonesia region as a consequence of Indo-Australian plate subduction under the Eurasian plate. Tectonic earthquakes required to be studied because in large magnitude it can bring disaster. Therefore the precise of hypocenter determination needs to be done. In this study, hypocenter relocation is done by Single Event Determination method using hypo71. The data used are earthquake event data in Flores area which has magnitude > 4 SR at period between January 2010 and March 2018 obtained from BMKG catalog. Hypo71 requires data of arrival time of P and S waves at the recorder station. The arrival time of P and S waves data at each station is obtained by picking P and S waves using SeisGram2k70. The results showed that the source of the earthquake experienced a change of position both horizontally and vertically. In the vertical direction of hypocenter earthquake changes in the distance between 0.02 - 89.61 km, while in the horizontal direction the hypocenter of the earthquake changes in the distance of 1.11 - 71.11 km. After relocation, the hypocenter of the earthquake distributed along the Back Arc Trust in the northern island of Flores. Hypocenter relocation using hypo71 yields a small residual between the observation time and calculation time denoted by RMS <1
Landslide Analysis Using Seismic Refraction Tomography And MASW: a Case Study in Ponorogo, East Java, Indonesia
Get PDFPonorogo district morphology form consisting of highlands and hills make this area vulnerable to landslides. Based on the BNPB (National Disaster Management Agency) data from 2013 to 2017, 77 landslides and 35% have occurred in Ngrayun and Slahung sub-districts. One area that has the potential to experience landslides is Tugurejo village in Slahung District. This study aims to determine the physical properties of subsurface rocks using SRT (Seismic Refraction Tomography) and MASW (Multi-channel Analysis of Surface Waves). The seismic velocity distribution defined from the SRT and MASW at the study sites shows a zone with a higher porosity that is interpreted to represent the level and depth of rock mass movement. P-wave velocity and S-wave indicates very low velocity of 500 – 1200 m/s and 100 – 250 m/s at depths up to 5 m
Estimation of the Source Parameters of the Flores Earthquake and Their Correlation to Aftershocks
Get PDFThis study uses data provided by BMKG Indonesia which is downloaded from the website www.webdc.eu. The data processing is done by using some software, one of them is Matlab to run Isola software. The software provides information about the fault direction. In addition, this study also uses Coulomb 3.3 software to provide information on subsequent earthquake forecasts. The results showed that the earthquake that occurred on 27th February 2015 gave impact to Coulomb's increase and decrease of stress to some areas in the northern mainland of Flores. The impact of this major earthquake is expected to trigger an earthquake that occurred in northern Flores. Based on the results of data processing obtained form focal mechanism is oblique reverse with the first nodal value strike 139, dip 73, and rake 50. While on the second nodal has a strike value 30, dip 43, and rake 154. Main earthquake impact Coulomb stress increase of 0.15-0.2 bar. Meanwhile, Coulomb stress result obtained shear value -18.890, normal -0.217, and Coulomb -19.976
Numerical Investigation of Over Fire Air (OFA) Effect on Flow Characteristics, NOx Combustion and Emission in a 600 Mw Tangentially Fired Pulverized Coal Boiler
Get PDFOne of the coal-fired air emissions in boilers is NOx, which has a significant impact on the environment and could cause acid rain, ozone formation, visual impairment and health problems in humans. There are several technologies to reduce and control the formation of NOx emissions, which one of these technologies is the use of over-fire air (OFA). In this research will observe the effect of overfire air (OFA) usage and analyze by numerical 3D modeling method using computational fluid dynamics (CFD) in Paiton 9 power plant boiler and analyzed for 5 (five) OFA damper opening variations, i.e 0%, 25%, 50 %, 75% and 100%. This research will analyze several factors that have significant influence on NOx emission formation, that are: the temperature distribution of the boiler during the combustion process, the distribution of nitrogen oxide (NO) and carbon dioxide (CO2), direction of flue gas flow and trajectory of coal particles and residence time indicating the length of time of burning. The results showed that the lower the flame temperature, the smaller the formation of NOx; the smaller the oxygen content in the combustion process, the smaller the formation of NOx; the shorter the residence time of combustion products in the high temperature zone the smaller the formation of NOx, and the smaller the nitrogen content in coal, the smaller the formation of NOx
The Effect of Fan Blade Radiator Gas Turbin Generator Angle on Auxiliary Cooling Water System Performance
Get PDFAuxiliary Cooling Water System (ACWS) on Gas turbine Blok 1 No 3 Muara Karang has declined its reliability because of 4 fan radiators must be operated due to increasing ambient air temperature and increase inspection interval from 8000 to 32.000 EOH after Upgrade in turbine part. This study aims to optimize Radiator ACWS performance by increasing the cooling fan air mass flow by changing the fan blade angle so it can be operated with 3 fan on and 1 fan standby. This research began with taking data each measurement at 11°, 13°, 15°, 17°, and 19°. Then, it will simulated by software to know the influence of air mass flow addition due to the change of the blade fan angle to the radiator water outlet temperature and to know the input operating parameters when the temperature outlet radiator is 46°C. The results of this study is validation of experimental and numerical data calculations that have errors below 5%. The maximum angle of fan blade can be set until 19°. At 16.7° with operation 3 of 4 fan on, radiator temperature output is 46° and heat disposed is 627.2 kW where this value is the same value as the current condition
Range Finding Test of Scirpus Grossus on Aluminium and Iron Contaminated Soil
Get PDFHigh concentration metal in soil may cause pollution. Particularly for aluminium and iron in soil. Even though these substances are necessary micro-substances for plants, but if the soil has it in high concentration, it will cause more complex environmental problem. These two metals were found in high concentration in soil near the small Industry Environment that recycled aluminium in Jombang Regency, East Java. High concentration also caused soil contamination, thus treatment towards the land was needed. One of the best solutions to overcome land contamination was phytoremediation. Scirpus grossus, to date, is the most widely used wild plant which has the ability in remediating metal pollutant in soil. Before treating metal on soil, toxicity test needed to be done beforehand. Toxicity test was done using Range Finding Test (RFT) method for 7 days using reactors with each filled with 5 kg of soil and 4 plants. RFT was done in different concentration composition between Al:Fe. The load variation (mg/kg) of Al:Fe in the reactors were 10.000:0, 5.000:50, 500:500, 50:5.000, 0:10.000 and control reactor. The result obtained after 7 days were that Scirpus grossus plant could survive in pollution load of Al:Fe 500:500 (mg/kg) with 75% percentage of living plants
Eksperimental Study the Effect of Additional Flat Plate Reflector to Performance the Sinusoidal Solar Water Heater
No full textNew Renewable Energy is currently not fully utilized. Energy sourced from the sun is one of the most exploited energy sources today in several countries in the world, which in large scale has been used as a power plant. The solar collector is a heat exchange device that serves to convert solar radiation energy into a form of heat energy to heat a working fluid, such as water and air. Various methods have been undertaken to improve the performance of solar collectors, including using flat plate reflectors. Reflectors are used to reflect the diffused sunlight to focus on solar cells and ultimately increase the value of solar cell output power. Experimental studies in this study were conducted to see the performance of a solar collector sinusoidal with and without the addition of reflectors under varying discharge conditions. Variations of mass flow rate in this study were 18 and 20 liters/hour. The reflector angle on the solar collector is set at 40° on both sides of the reflector. From this study, the results for the efficiency of a solar collector with the addition of a reflector are the highest at 43,91% at a mass flow rate of 20 liters / hour
Isobaric Vapor-Liquid Equilibria for Binary System of Ethanol (1) + Eugenol (2) at 400 and 760 mmHg
Get PDFEugenol is the main component of clove oil, while the main impuritis of it is β-caryophyllene. Eugenol with a purity higher than 98% has a higher price than low purity eugenol. Thus, further eugenol purification process is needed. Common purification processes are extraction and distillation. In the design and simulation of the distillation process it requires a knowledge of Vapor-Liquid Equilibrium (VLE) data from a mixture of components to be separated (eugenol and ethanol) as the result of extraction process. In this work, the experimental VLE data were measured for binary mixtures of ethanol(1) + eugenol(2) at 400 and 760 mmHg. The apparatus used for this experiment is an othmer still equipped with a vacuum pump and a manometer. The experiments were performed to obtain equilibrium data (T), component concentrations in liquid phase (x), and in vapor phase (y). The binary VLE data were correlated with the Wilson, NRTL and UNIQUAC models to obtain the binary parameters. The reliability of these models were tested by comparing with experimental results using Root Mean Square Deviation (RMSD). For the system and the operation condition studied, the Wilson, NRTL and UNIQUAC models suited well and give satisfactory results based on the RMSD values
Effects of Pilot Injection Timing on The Engine Performance of A Diesel Dual Fuel Engine
Get PDFThe combustion process in dual fuel diesel engines occurs sequentially starting with premix burning. The premix burning starts with the ignition delay process. The presence of CNG causes the ignition delay process to become longer, thereby reducing engine performance and increasing emissions on dual fuel diesel engines. This study uses diesel engine type Diamond DI 800 with dual fuel indirect injection model system. The method used a variation of diesel pilot injection timing 110 CA, 130 CA, 150 CA, 170 and 190 CA BTDC. Testing is done with a constant engine speed of 1500 rpm and loading 500 to 3000 watts with 500-watt intervals. The results show that by advancing the diesel pilot injection timing where brake horsepower and the average effective pressure between single fuel and dual fuel is not too far as the current and voltage changes generated by the generator are not too small. While optimal thermal efficiency increased by 4.11%, while CO and HC emissions decreased respectively by 10.85% and 8.28% at occurred at the pilot injection timing 170 CA BTDC but still under the single fuel engine