• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.26 no.6
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• pp.287-293
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• 2014

Internal combustion engines release 30~40% of the energy from fossil fuels into the atmosphere in the form of exhaust gases. By utilizing this waste heat, plenty of energy can be conserved in the auto industry. Thermoelectric generation is one way of transforming the energy from engine's exhaust gases into electricity in a vehicle. The thermoelectric generators located on the exhaust pipe have been developed for vehicle applications. Different experiments with thermoelectric generators have been conducted under various test conditions as following examples: hot gas temperature, hot gas mass flow rate, coolant temperature, and coolant mass flow rate. The experimental results have shown that the generated electrical power increases significantly with the temperature difference between the hot and the cold side of the thermoelectric generator and the gas flow rate of the hot-side heat exchanger. In addition, the gas temperature of the hot-side heat exchanger decreases with the length of the thermoelectric generator, especially at a low gas flow rate.

• Aerospace Engineering and Technology
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• v.12 no.1
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• pp.105-110
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• 2013

The gimbal expansion joint for the pipe line of a liquid rocket engine undergoes high pressure and cyclic rotational displacement loadings. In present study, the moment analyses and tests of the internal-type gimbal expansion joint for the engine were performed. The moment components due to spring stiffness, friction and lateral force were obtained using a analytic method and their sums at low and high pressures were compared with the test results. Also, applying a $MoS_2$ dry film lubricant to the pin of a external hinge expansion joint, it is tested that the galling of the pin was removed and the friction coefficient was decreased for low pressures.

• Plant Journal
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• v.9 no.3
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• pp.48-52
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• 2013

In this study, the internal flow field of SCR Denitrification Plant was simulated by using Computational Fluid Dynamics(CFD). In order to analyze the uniformity of flow field, an interpretation on the pre-existing facilities was performed, and some moot points were identified and compensated through this analysis. The compensatory methods include the installation of the Porous Plate below the bottom of the Baffle to create uniform flow and also, and the Guide Vane was also placed in the bend of pipe to guide the flow uniformly. Lastly, the Baffle was installed to deduct equalized space distribution of the air flow, initially flowed into the SCR Plant.

• Journal of the Speleological Society of Korea
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• no.79
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• pp.77-81
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• 2007

In this paper deals with behavior of the magnetic abrasive using Sr-Ferrite on polishing charateristiccs in a internal finishing of staninless steel pipe a tying magnetic abrasive polishing. The magnetic polishing is the useful method to finish some machinery fabrications by using magnetic power. This method is one of the precision techniques and has in aim for clean technology in the transportation of the pure gas in the clean pipes. The magnetic abrasive polishing method is not so common in the field of machine that it is not known to widely. There are rarely researcher in this field because of non-effectiveness of magnetic abrasive. Therefore, in this paper we deals with the development of the magnetic abrasive with the use of Sr-Ferrite. In this development, abrasive grain SiC has been made by using the resin bond fabricated at low temperature. And magnetic abrasive powder was fabricated from the Sr-Ferrite which was crushed into 200 mesh. The XRD analysis result shows that only SiC abrasive and Sr-Ferrite crystal peaks were detected, explaining that resin bond was not any more to contribute chemical reaction. From MACRO analysis, we found that SiC abrasive and Sr-Ferrite were strongly bonding with each other.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.624-626
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• 1993

The Electrical Charge generated by friction in flowing insulating oil can create hazadous accidents. Neutralization of static charges in the oil during transportation is an obvious method of overcoming the problem of internal electric charge. It is known that SCR(Static Charge Reducer) can neutralize much of this charge by the needle electrode and mixing it with the original charge. In our experiment, a filter to generate static charge was set just befor a measurement pipe, and streaming current from the filter to the earth $I_s$, current from the electrode to the earth $I_e$ and current from the receiving tank to the earth $I_f$ were measured in a steady state. As a result, charge density and needle electrode current increases with increasing of oil temperature. Charge elimination rate decreases with increasing of oil flow rate, and increases with increases of oil temperature. Faraday Cage current decreases with increasing of oil temperature.

• Journal of the Korean Institute of Gas
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• v.14 no.4
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• pp.45-50
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• 2010

The marine pipelines laid in deep waters were evaluated to verify the resistance on the plastic collapse to heavy ambient external pressure due to hydrostatic pressure. In this study, the plastic collapse behavior of the marine pipe subjected to hydrostatic pressure was evaluated with the ovality and ratio of diameter to thickness in FE analyses. A parametric study was shown that the internal pressure increased the plastic collapse depth by increasing of the resistance to the plastic collapse. It was also shown that the collapse depth of the pipeline having a local ovality was deeper than that of the pipeline having a global ovality. Finally, the plastic collapse depth decreased when either the ratio of diameter to thickness or the ovality increased.

• Nuclear Engineering and Technology
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• v.48 no.6
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• pp.1412-1422
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• 2016

Austenitic stainless steels (ASSs) are widely used for nuclear pipes as they exhibit a good combination of mechanical properties and corrosion resistance. However, high tensile residual stresses may occur in ASS welds because postweld heat treatment is not generally conducted in order to avoid sensitization, which causes a stress corrosion crack. In this study, round robin analyses on stress intensity factors (SIFs) were carried out to examine the appropriateness of structural integrity assessment methods for ASS pipe welds with two types of circumferential cracks. Typical stress profiles were generated from finite element analyses by considering residual stresses and normal operating conditions. Then, SIFs of cracked ASS pipes were determined by analytical equations represented in fitness-for-service assessment codes as well as reference finite element analyses. The discrepancies of estimated SIFs among round robin participants were confirmed due to different assessment procedures and relevant considerations, as well as the mistakes of participants. The effects of uncertainty factors on SIFs were deducted from sensitivity analyses and, based on the similarity and conservatism compared with detailed finite element analysis results, the R6 code, taking into account the applied internal pressure and combination of stress components, was recommended as the optimum procedure for SIF estimation.

• Journal of Welding and Joining
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• v.23 no.6
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• pp.61-66
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• 2005

A probabilistic approach for evaluating failure risk is suggested in this paper. Probabilistic fracture analyses were performed for a pressurized pipe of a Cr-Mo steel reflecting variation of material properties at high temperature. A crack was assumed to be located along the weld fusion line. Probability density functions of major variables were determined by statistical analyses of material creep and creep crack growth data measured by the previous experimental studies by authors. Distributions of these variables were implemented in Monte Carlo simulation of this study. As a fracture parameter for characterizing growth of a fusion line crack between two materials with different creep properties, $C_t$ normalized with $C^*$ was employed. And the elapsed time was also normalized with tT, Resultingly, failure probability as a function of operating time was evaluated fur various cases. Conventional deterministic life assessment result was turned out to be conservative compared with that of probabilistic result. Sensitivity analysis for each input variable was conducted to understand the most influencing variable to the analysis results. Internal pressure, creep crack growth coefficient and creep coefficient were more sensitive to failure probability than other variables.

• Journal of Fisheries and Marine Sciences Education
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• v.26 no.6
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• pp.1435-1441
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• 2014

The fire took place in the synthetic heat transfer fluid boiler used in production process of medium density fiberboard. This study investigated pressure distribution of the first, second and third passes and the temperature in the fire burner. The boiler's internal fluid is unsteady due to the out of order inverter. As the operation continues, the flame's flow and speed are unsteady. The synthetic heat transfer fluid leak spouted about 120kg/min in the form of vapor in the early period of the fire. The flame extended to the second and third passes. The highest temperature of the second and third pass is $1059^{\circ}C$ and $1007^{\circ}C$, respectively. The synthetic heat transfer fluid spouted through the cracked part of the fire box in the first pass and accumulated on the turn table. Therefore, it is expected that the temperature of the interior of the fire box is above $1200^{\circ}C$. The temperature of the burner rises to a maximum level several times in a short period. On account of that, several explosions occur in the fire burner. Pressure distribution at steady state in combustion furnace is 2~5mAq and pressure distribution at inverter under fault condition in combustion furnace is 10~-53mAq. The decrement of coil thickness measurement for synthetic heat transfer fluid boiler is 0~5mm.

• Journal of Preventive Medicine and Public Health
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• v.54 no.2
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• pp.137-144
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• 2021

Objectives: The aim of this study was to identify factors associated with quitting smoking in Indonesia Methods: Data on 11 115 individuals from the fifth wave of the Indonesia Family Life Survey were analyzed. Quitting smoking was the main outcome, defined as smoking status based on the answer to the question "do you still habitually (smoke cigarettes/smoke a pipe/use chewing tobacco) or have you totally quit?" Logistic regression was performed to identify factors associated with successful attempts to quit smoking. Results: The prevalence of quitting smoking was 12.3%. The odds of successfully quitting smoking were higher among smokers who were female (adjusted odds ratio [aOR], 2.69; 95% confidence interval [CI], 2.08 to 3.33), were divorced (aOR, 2.45; 95% CI, 1.82 to 3.29), did not chew tobacco (aOR, 3.01; 95% CI, 1.79 to 5.08), found it difficult to sacrifice smoking at other times than in the morning (aOR, 1.29; 95% CI, 1.14 to 1.46), and not smoke when sick (aOR, 1.32; 95% CI, 1.14 to 1.54). About 59% of variance in successful attempts to quit smoking could be explained using a model consisting of those variables. Conclusions: Female sex, being divorced, not chewing tobacco, and nicotine dependence increased the odds of quitting smoking and were associated with quitting smoking successfully. Regular and integrated attempts to quit smoking based on individuals' internal characteristics, tobacco use activity, and smoking behavior are needed to quit smoking.