• Journal of Urban Science
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• v.12 no.2
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• pp.53-64
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• 2023

With the development of the plant industry, there has been an increasing frequency of major accidents both domestically and internationally, emphasizing the importance of plant safety. Therefore, this study aims to investigate measures to enhance the stability of piping, a key component within the plant. Upon examining the piping, erosion, buckling, and fatigue emerged as significant risk factors among various potential hazards, leading to their selection as the primary risk factors in this study. Identifying variables that can collectively mitigate these factors, the study focuses on the material, thickness, and elbow angle of the piping. The reference piping model is established as the pipeline connecting the Skim Tank and IGF within a 300BPD oil sands modular plant in Yeoncheon, Gyeonggi-do. Utilizing the FEA analysis program ANSYS, the study conducts a variable analysis for the identified risk factors. The results of the analysis, through comparison and evaluation, provide evidence of the effectiveness of enhancing stability. It is observed that reducing the elbow angle significantly improves erosion and buckling, while changing to a material with high yield stress most significantly enhances stability when considering fatigue.

• Journal of the Korean Society for Nondestructive Testing
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• v.15 no.2
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• pp.371-377
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• 1995

By using ultrasonic waves, we obtained conclusion from the experiment for measuring joint axial force of high tension bolt. The conclusion is followed. : From the high tension bolts used at turbine of Thermoelectric Power Plant, we obtained the equation of calculating joint axial force that is ${\sigma}=\frac{{\Delta}BPD}{j{\times}{\Sigma}{\delta}}$. By using IBM PC, which is inputed by the equation for calculating joint axial force of high tension bolts, we got joint axial force of high tension bolts form beam path of ultrasonic waves. Furrther, we can identify that constitution of plant safety inspection system is possible.

• Korean Chemical Engineering Research
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• v.47 no.1
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• pp.127-132
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• 2009

This report examines the economic feasibility of a commercial 50,000 barrel per day direct coal liquefaction(DCL) facility to produce commercial-grade diesel and naphtha liquids from medium-sulfur bituminous coal. The scope of the study includes capital and operating cost estimates, sensitivity analysis and a comparative financial analysis. Based on plant capacity of 50,000BPD, employing Illinois #6 bituminous coal as feed coal the total capital cost appeared $3,994,858,000. Also, the internal rate of return of DCL appeared 6.60% on the base condition. In this case, coal price and sale price of products were the most influence factors. And DCL's payback period demanded a long time(12.3 years), because of high coal price at the present time. According to sensitivity analyses, the important factors on DCL processes were product sale price, feed coal price and the capital cost in order.

• Clinical and Experimental Pediatrics
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• v.52 no.8
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• pp.881-887
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• 2009

Purpose : The survival rate of very low birth weight infant (VLBWI) had increased as a result of advances in neonatal intensive care. We evaluated the changes in outcomes of VLBWI who admitted to the neonatal care unit of Hallym University Kangnam Sacred Heart Hospital. Methods : Retrospective review of 339 VLBWI who were born from 1st January 1997 to 31th December 2008 were performed. Outcomes including survival rate, birth weight (BW), gestational age (GA), morbidities, and mortality between period I (1997- 2003) and period II (2004-2008) were compared. Results : Overall incidence of VLBWI was 2.3% and it was significantly higher in period II(3.3%). Mean BW and GA were significantly decreased in period II (P<0.001, P=0.01). The survival rate increased from period I (59.1%) to period II (74.2%). BW-specific survival rate increased in 1,000-1,249 gm and GA-specific survival rate significantly increased in 27-28 weeks and 29-30 weeks. The incidences of respiratory distress syndrome (RDS), retinopathy of prematurity (ROP), sepsis, bronchopulmonary dysplasia (BPD), intraventricular hemorrhage, periventricular leukomalacia, and necorotizing enterocolitis were same except patent ductus arteriosus. Conclusion : The survival rate of VLBWI was increased in period II, especially in less than 1,000 gm and below 27 weeks. This may be due to recent dramatic improvement of neonatal care. But more efforts are needed to improve outcome during initial phase and to reduce long term complication such as BPD and ROP.

• Neonatal Medicine
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• v.17 no.2
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• pp.201-206
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• 2010

Purpose: Recently, after patent ductus arteriosus (PDA) ligation in preterm infants, unexplained hemodynamic instabilities are reported. To determine the incidence, risk factors and clinical manifestations of hemodynamic instability after PDA ligation in very low birth weight (VLBW) infants. Methods: This retrospective multicenter study enrolled 18 VLBW infants who underwent PDA ligation from January 2002 to February 2008. Hemodynamic instability defined as unexplained cardiopulmonary dysfunction with increased dependency on mechanical ventilation and decreased blood pressure. Results: The mean gestational age and birth weight (BW) of all infants were $27^{+6}{\pm}1^{+6}$ weeks and 951${\pm}$245 g. Hemodynamic instability group (HI) included seven infants (39%) and hemodynamic stability group (HS) included 11 infants (61%). Compared to HS, HI had lower BW (1,033${\pm}$285 g vs. 821${\pm}$126 g, P=0.048) and weight on operation day (1,195${\pm}$404 g vs. 893${\pm}$151 g, P=0.042), longer hospital days (105${\pm}$29 vs. 141${\pm}$39, P=0.038), more severe bronchopulmonary dysplasia (BPD), (no/mild/moderate/severe, 2/5/2/2 vs. 0/1/2/4, P=0.038) and higher preoperative $FiO_2$ (0.29${\pm}$0.06 vs. 0.38${\pm}$0.09, P=0.02). One case of mortality due to sepsis, which was not associated with ligation, was observed among HS. Conclusion: The incidence of hemodynamic instability after PDA ligation in VLBW infants was 39%. Low BW, low weight on operation day and preoperative high $FiO_2$ might be risk factors of hemodynamic instability after PDA ligation in VLBW infants. The hemodynamic instability could increase the severity of BPD and hospital days.

• Neonatal Medicine
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• v.15 no.2
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• pp.151-159
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• 2008

Purpose : This study determined the prenatal and postnatal factors associated with complications and prognosis in premature infants with leukemoid reaction. Methods : We retrospectively reviewed the medical records of premature infants with gestational ages <37 weeks and low birth weights (<2,500 g) who were admitted immediately after birth to the neonatal intensive care unit at the Dongguk University Ilsan Hospital between June 2005 and July 2006. A leukemoid reaction was defined as an absolute neutrophil count (ANC) >30,000/$mm^3$. The infants who had leukemoid reaction comprised the study group, while the remainder of infants made up the control group. The relationships between maternal and neonatal variables and ANC were studied. Results : Leukemoid reaction was detected in 3.1% of the study infants (8 of 252). Factors more frequently associated with infants with leukemoid reaction were as follows: maternal chorioamnionitis, high levels of maternal and infant C-reactive protein, gestational age <37 weeks, birth weight <2,500 g, low Apgar score, prolonged ventilator support, and a high incidence of bronchopulmonary dysplasia (BPD). However, there were no significant differences with respect to the antenatal usage of steroids, the incidences of patent ductus arteriosus, necrotizing enterocolitis, intraventricular hemorrhage, retinopathy of prematurity, and mortality between the two groups. Conclusion : Leukemoid reaction in premature infants was associated with chorioamnionitis and high levels of serum C-reactive protein in mothers and infants, and BPD in infants. These findings suggest that leukemoid reaction is secondary to inflammation caused by infection.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2002.11a
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• pp.171-184
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• 2002

Approx. 200,000 bpd vacuum residue oil is produced from oil refineries in Korea. These are supplying to use asphalt, high sulfur fuel oil, and upgrading at the residue hydro-desulfurization unit. Vacuum residue oil has high energy content, however high sulfur content and high concentration of heavy metals represent improper low grade fuel. To meet growing demand for effective utilization of vacuum residue oil from refineries, recently some of the oil refinery industries in Korea, such as SK oil refinery and LG Caltex refinery, have already proceeded feasibility study to construct 435-500 MWe IGCC power plant and hydrogen production facilities. Recently, KIER(Korea Institute of Energy Research) are studing on the Vacuum Residue gasification process using an oxygen-blown entrained-flow gasifier. The experiment runs were evaluated under the reaction temperature : 1,100~1,25$0^{\circ}C$, reaction pressure : 1~6kg/$\textrm{cm}^2$G, oxygen/V.R ratio : 0.8~0.9 and steam/V.R ratio : 0.4-0.5. Experimental results show the syngas composition(CO+H$_2$) : 85~93%, syngas flow rate : 50~110Mm$^3$/hr, heating value : 2,300~3,000 ㎉/Nm$^3$, carbon conversion : 65~92, cold gas efficiency : 60~70%. Also equilibrium modeling was used to predict the vacuum residue gasification process and the predicted values were compared reasonably well with experimental data.

• Journal of Energy Engineering
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• v.12 no.1
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• pp.49-57
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• 2003

Approx. 200.000 bpd vacuum residue oil is produced from oil refineries in Korea, and is supplied to use asphalt, high sulfur fuel oil and for upgrading at the residue hydro-desulfurization unit. Vacuum residue oil has high energy content, however its high sulfur content and high concentration of heavy metals represent improper low grade fuel. To meet growing demand for effective utilization of vacuum residue oil from refineries, recently some of the oil refinery industries in Korea, such as SK oil refinery and LG Caltex refinery, have already proceeded feasibility study to construct 435~500 MWe IGCC power plant and hydrogen production facilities. Recently, KIER (Korea Institute of Energy Research) are studying on the Vacuum Residue gasification process using an oxygen-blown entrained-flow gasifier. The experiment runs were evaluated under the reaction temperature: 1.100~l,25$0^{\circ}C$, reaction pressure: 1~6 kg/$\textrm{cm}^2$G, oxygen/V.R ratio: 0.8~0.9 and steam/V.R ratio: 0.4~0.5. Experimental results show the syngas composition (CO+H$_2$): 85~93%, syngas flow rate: 50~l10 Nm$^3$/hr, heating value: 2,300~3,000 k㎈/Nm$^3$, carbon conversion: 65~92, cold gas efficiency: 60~70%. Also equilibrium modeling was used to predict the vacuum residue gasification process and the predicted values were compared reasonably well with experimental data.