• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.2
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• pp.275-281
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• 2018

It is known that he pollutant emitted from the combustion process of marine fuel oil causes air pollution and harmful effects to the human body. Accordingly, IMO regulates pollutants emitted from ships. However, the regulation of Particulate Matter (PM) is still in the process of debate, so preemptive action is needed. Fundamental research on PM is essential. In this study, the Dimensionless Light Extinction Constant ($K_e$) of fuel oil used in marine diesel engines was measured and analyzed to construct the basic data of the PM generated from marine-based fuel oil. The fuel oil used in the land diesel engine was measured in the same way for character comparison. Both fuel oils differ in sulfur content and density. The $K_e$ was measured via the optical method using a 633 nm laser and was determined by using the volume fraction of PM collected by the gravimetric filter method. The $K_e$ of the PM discharged from marine fuel oil is 8.28, and the land fuel oil is 8.44. The $K_e$ of two fuel oils was similar within the measurement uncertainty range. However, it was found by comparison with the value obtained by the Rayleigh-Limit solution that the light scattering portion could be large. Also, it was found that light extinction characteristics could be different due to the relationship between light transmittance and collected mass.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.6
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• pp.655-662
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• 2012

Gas leakage in an oil refinery causes damage to the environment and unsafe conditions. Therefore, it is necessary to develop a technique that is able to detect the location of the leakage and to filter abnormal gas-leakage signals from normal background noise. In this study, the adaptation filter of the finite impulse response (FIR) least mean squares (LMS) algorithm and a cross-correlation function were used to develop a leakage-predicting program based on LABVIEW. Nitrogen gas at a high pressure of 120 kg/$cm^2$ and the assembled equipment were used to perform experiments in a reverberant chamber. Analysis of the data from the experiments performed with various hole sizes, pressures, distances, and frequencies indicated that the background noise occurred primarily at less than 1 kHz and that the leakage signal appeared in a high-frequency region of around 16 kHz. Measurement of the noise sources in an actual oil refinery revealed that the noise frequencies of pumps and compressors, which are two typical background noise sources in a petrochemical plant, were 2 kHz and 4.5 kHz, respectively. The fact that these two signals were separated clearly made it possible to distinguish leakage signals from background noises and, in addition, to detect the location of the leakage.

• Journal of the Korean Institute of Gas
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• v.22 no.2
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• pp.78-83
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• 2018

The purpose of this paper is to study for failure examples of emission gas recirculation and air control and catalyzed particulate filter system in diesel engine vehicle. The first example, the researcher found the fact that the much engine oil came into the intake manifold causing diaphragm damage of EGR valve. The engine oil entered into combustion chamber of engine so that a car emit the polluted exhaust gas when driving. The second example, the researcher certified the sticking phenomenon of carbon and foreign substance with the throttle flap so that the exhaust fumes discharged exhaust port. The third example, the regeneration function don't activated to not detect the temperature of exhaust gas because of damage in the sensor. Thus, the researcher must meticulously manage his car not in order to take place the problem of environmental pollution.

• Journal of the Korean Ceramic Society
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• v.42 no.3 s.274
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• pp.165-170
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• 2005

Sol-gel methods offer many advantages over conventional slip-casting, including the ability to produce ceramic membranes. They are purer, more homogeneous, more reactive and contain a wider variety of compositions. We produced ormosil sol using sol-gel process under various molecular weight of polymer species[polyethylene glycol(PEG)] in total system [Tetraethyl ortho silicate(TEOS)-polyethylene glycol(PEG)]. The properties of as-prepared ormosil sol such as viscosity and gelation time are characterized. Also, the ceramic membrane was prepared by dip-coating with synthetic sol and its microstructure was observed by scanning electron microscopy. The permeability and rejection efficiency of membrane for oil/water emulsion were evaluated as cross­flow apparatus. The ormosil sol coated membrane was easily formed by steric effect of polymer and it improved flux efficiency because infiltration into porous support decreased. Its flux efficiency was elevated about $200\;l/m^2h$ compared with colloidal sol coated membrane at point of five minutes from starting test.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.6
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• pp.529-536
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• 2015

A defect could be generated in bolts for a use of oil filters for the manufacturing process and then may affect to the safety and quality in bolts. Also, fine defects may be imbedded in oil filter system. So it is very important that such defects be investigated and screened during the multiple manufacturing processes. Therefore, in order effectively to evaluate the fine defects, the FEM simulations were performed to make characterization in the crack detection of the bolts and the parameters such as number of turns of the coil, the coil size, applied frequency were calculated based on the simulation results. Simulations were carried out for the defect signal of eddy current probe. Exciter and receiver were utilized. In this paper, the FEM simulations were performed in both bobbin-type and pancake-type probe, both probes were optimized under Eddy current FEM simulations and the results of calculation were discussed.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.5
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• pp.1121-1129
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• 1988

An economic and efficient system for measuring drop sizes was developed. Pattern recognition technique was used with conventional oil-bath sampling and photographic method. The system was designed to measure and count relatively large number of drops in a very short time, and also to filter out abnormal images such as drops in contact or overlap as well as odd-shaped foreign materials. In this measuring system, most important error originates from the process of converting the original image to the binary image. If the photograph contains a large number of spray drops, the relative size of the pixel to the drops is not infinitesimally small; thus the proper choice of threshold level to convert the original image to the binary image becomes very important. In present case, most of the images lay in one of the two separate bands of brightness level and the arithmetic mean of the most popular brightness levels from each band was chosen as the threshold level. Present image processing system reduces the subjective error by the observers in counting and measuring drops and turns out to be substantially effective. The processing time can be further reduced by improving the hardware system concerned with the digital image coding.

• Journal of Convergence Society for SMB
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• v.1 no.1
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• pp.39-44
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• 2011

Recently, due to people's incontinent use all over the world, fossil fuels such as coal, oil, and natural gas were nearly to be exhausted and also causes serious environment pollutions. Therefore, there is a strong need to develop solar, wind, hydro, biomass, geothermal to replace fossil fuels to prevent suffering from above problems. Wish advances in sensor technology, such data is collected as a kind of stream data which arrives in an online manner so that it is characterized as high- speed, real-time and unbounded and it requires fast data processing to get the up-to-date results. Therefore, the traditional data processing techniques are not fit to deal with stream data. In this paper, we propose a kalman filter-based algorithm to process renewable stream data.

• New & Renewable Energy
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• v.8 no.4
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• pp.38-43
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• 2012

Biodiesel is non-petroleum based fuel produced from vegetable oils or animal fats through transesterification. The compositions of saturated and unsaturated fatty acids in the feedstocks are important factors for biodiesel quality in terms of low-temperature fluidity and oxidative stability. The goal of this study is to improve the cold flow property of biodiesel from vegetable and animal origin containing highly saturated methyl esters (approx. 50%). In this purpose poly-saturated methyl esters in palm and tallow biodiesel were removed via urea-based fractionation and then the recovered fractions (enriched unsaturated fatty acid methyl esters) were supplemented with cold flow improvers. The highest concentration of unsaturated fatty acid methyl esters (93.8%) was obtained using a urea/fatty acid ratio of 3:1 at the crystallization temperature of $0^{\circ}C$ for 17 hours in incubation, with recovery of 71% and the addition of cold flow improver (Flozol$^{(R)}$ 515, 3,000 ppm) to the enriched poly-unsaturated fatty acid methyl esters reduced the CFPP(cold filter plugging point) of palm biodiesel from $12^{\circ}C$ to $-42^{\circ}C$. In tallow biodiesel both the enrichment of unsaturated fatty acid methyl esters (93.71%) and the addition of cold flow improver (Infineum R408, 3,000ppm) reduced the CFPP from $10^{\circ}C$ to $-32^{\circ}C$.

• The Korean Journal of Petroleum Geology
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• v.11 no.1 s.12
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• pp.9-17
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• 2005

In the main target area of the block II, Targe-scale faults occur below the unconformity developed around 1 km in depth. The contrast of seismic velocity around the unconformity is generally so large that the strong multiples and the radical velocity variation would deteriorate the quality of migrated section due to serious distortion. More than 15 kinds of data processing techniques have been applied to improve the image resolution for the structures farmed from this active crustal activity. The bad and noisy traces were edited on the common shot gathers in the first step to get rid of acquisition problems which could take place from unfavorable conditions such as climatic change during data acquisition. Correction of amplitude attenuation caused from spherical divergence and inelastic attenuation has been also applied. Mild F/K filter was used to attenuate coherent noise such as guided waves and side scatters. Predictive deconvolution has been applied before stacking to remove peg-leg multiples and water reverberations. The velocity analysis process was conducted at every 2 km interval to analyze migration velocity, and it was iterated to get the high fidelity image. The strum noise caused from streamer was completely removed by applying predictive deconvolution in time space and ${\tau}-P$ domain. Residual multiples caused from thin layer or water bottom were eliminated through parabolic radon transform demultiple process. The migration using curved ray Kirchhoff-style algorithm has been applied to stack data. The velocity obtained after several iteration approach for MVA (migration velocity analysis) was used instead or DMO for the migration velocity. Using various testing methods, optimum seismic processing parameter can be obtained for structural and stratigraphic interpretation in the Block II, Yellow Sea Basin.

• Journal of the Korean Applied Science and Technology
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• v.30 no.1
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• pp.35-48
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• 2013

Biodiesel is an alternative diesel fuel which can be obtained from the transesterification of vegetable oils, animal fats and waste cooking oil. The objective of this study is to evaluate the properties of biodiesel obtained from different feedstocks (soybean, waste cooking, rapeseed, cottonseed and palm oils). The biodiesel derived from different feedstocks was analyzed for FAME (fatty acid methyl esther) content, kinematic viscosity, flash point, CFPP (cold filter plugging point) and glycerin content. The quality of biodiesel was tested according to the Korean and European standard (EN14214, requirements and test method for biodiesel fuel). The biodiesels derived from soybean, waste cooking, rapeseed and cottonseed oils contain high amount of unsaturated fatty acid, while palm biodiesel is dominated by saturated fatty acid. The fuel properties of biodiesel, such as low temperature performance, kinematic viscosity and oxidation stability are correlated with the FAME composition components in biodiesel.