• Journal of Energy Engineering
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• v.12 no.4
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• pp.289-301
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• 2003

To develop a chemical-looping combustion technology, conceptual design of 50 kW thermal chemical-looping combustor, which is composed of two interconnected pressurized circulating fluidized beds, was performed by means of mass and energy balance calculations. A riser type fast fluidized bed was selected as an oxidizer and a bubbling fluidized bed was selected as a reducer by mass balance for the chemical-looping combustor. Calculated values of bed mass, solid circulation flux, and reactor dimension by mass and energy balance calculations were suitable for construction and operation of chemical-looping combustor. It is concluded from the comparison of the design results and operating values of commercial circulating fluidized bed that the process outline is realistic. Moreover, the previous results support that oxygen carrier particle, NiO/bentonite, fulfills the conversion rates needed for the proposed design. The effects of system capacity, metal oxide content in a oxygen carrier particle, amount of steam input, gas velocity, and solid depth on design values were investigated and the changes in the system performance can be estimated by proposed design tool.

• Magazine of the Korean Society of Agricultural Engineers
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• v.34 no.2
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• pp.73-84
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• 1992

The TIDE, finite element model for the simulation of tidal flow in shallow sea was tested for its applicability at the Saemangeum area. Several pre and post processors were developed to facilitate handling of the complicated and large amount of input and output data for the model developed. Also an operation scheme to run the model and the processors were established. As a result of calibration test using the observed data collected at 9 points within the region, linearlized friction coefficients were adjusted to be ranged 0.0027~0.0072, and water depths below the mean sea level at every nodes were changed to be increased generally by 1 meter. Comparisons of tidal velocities between the observed and the simulated for the 5 stations were made and obtained the result that the average relative error between simulated and observed tidal velocities was 11% for the maximum velocities and 22% for the minimum, and the absolute errors were less than 0.2m/sec. Also it was found that the average R.M.S. error between the velocities of observed and simulated was 0.119 m/sec and the average correlation coefficient was 0.70 showing close agreement. Another comparison test was done to show the result that R.M.S. error between the simulated and the observed tidal elevations at the 4 stations was 0.476m in average and the correlation coefficients were ranged 0.96~0.99. Though the simulated tidal circulation pattern in the region was well agreed with the observed, the simulated tidal velocities and elevations for specific points showed some errors with the observed. It was thought that the errors mainly due to the characteristics of TIDE Model which was developed to solve only with the linearized scheme. Finally it was concluded that, to improve the simulation results by the model, a new attempt to develop a fully nonlinear model as well as further calibration and the more reasonable generation of finite element grid would be needed.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.19 no.3
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• pp.14-22
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• 2023

Steel-pipe civil structures, including steel-pipe energy piles and cast-in-place piles (CIPs), utilize steel pipes as their primary reinforcements. These steel pipes facilitate the circulation of a working fluid through their annular crosssection, enabling heat exchange with the surrounding ground formation. In this study, the cooling performance of a ground source heat pump (GSHP) system that incorporated steel-pipe civil structures was investigated to assess their applicability. First of all, the thermal performance test was conducted with steel-pipe CIPs to evaluate the average heat exchange amount. Subsequently, a GSHP system was designed and implemented within an office container, considering the various types of steel-pipe civil structures. During the performance evaluation tests, parameters such as the coefficient of performance (COP) and entering water temperature (EWT) were closely monitored. The outcomes indicated an average COP of 3.74 for the GSHP system and the EWT remained relatively stable throughout the tests. Consequently, the GSPH system demonstrated its capability to consistently provide a sufficient heat source, even during periods of high cooling thermal demand, by utilzing the steel-pipe civil structures.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1480-1486
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• 2011

After installation of platform screen door (PSD) in subway stations, particulate matters (PMs), which are originally ventilated through the platform, are accumulated inside the tunnel of the subway system. It deteriorates an air quality inside the tunnel. To ventilate the accumulated PMs inside the tunnel, the natural ventilator which are located inside the tunnel (namely, tunnel ventilation system) are used as only one circulation system. In addition, the installation of PSD can affect to the aerodynamic variations inside the tunnel, since the PSD system was not considered factor when the tunnel ventilation system was designed. However, the researches about the tunnel ventilation system have not been adequate. Therefore, this study is carried out with two objectives: 1) to measure the velocity of air current by the train-induced wind, when the train passes through the tunnel, and 2) to investigate the typical patterns of air current by quantitatively evaluating the characteristics of inflow/outflow of air current which passes through the natural ventilation system. This study can suggest the basic standard to newly design the tunnel of the subway system as well as the ventilation system.

• KSBB Journal
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• v.22 no.3
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• pp.157-161
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• 2007

This study is to investigate the biological degradation and the characteristics of MEA, a pH regulator to be put in the cooling water circulation system for power plants, loading to elevate concentrations of COD and N when eluted into the water environment. MEA, $NH_4^+$ and CODcr were monitored in flask cultures and in a batch aerator. MEA was found to be biologically degradable, producing substantial amount of ammonia (max. 78.1%) in a form of $NH_4^+$ and other carboneous intermediates. The degradation reaction rates were similar one another over all MEA concentrations tested as the activated sludge (microbial consortium) was acclimated to MEA with the gradual and stepwise increase in MEA input into the batch aerator. Also, MLVSS kept increasing with increasing MEA input. The COD-based degradation reaction order was determined to be 1.

• Journal of Digital Convergence
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• v.18 no.6
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• pp.1-7
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• 2020

Amid growing interest in recycling around the world, the amount of waste is increasing despite the separate discharge efforts of each household, and it is difficult to find accurate data on recycling household waste. Also, recycling segregation is already settled in our daily lives, but we face a serious problem in which a significant portion of the recyclables collected are re-waste. In this study has been proposed a cash compensation system for recyclables, which is paid cash when the recyclables are washed clean and discharged. The cash compensation system proposed in this study could re-use 100% of the discharged recyclables, resulting in rewards for good deeds for individuals, greater returns for businesses and reduced disposal costs for local governments. In addition, it is expected that the government will be able to secure data related to the recycling of domestic waste, which will contribute to the management of recyclables at the national level.

• Journal of Chest Surgery
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• v.29 no.3
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• pp.303-310
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• 1996

From December of 1994 to April of 1995, we, SHUH Department of Pediatric Thoracic and Cardiovascular Surgery, studied effects of aprotinin. 95 patients were randomly divided into two groups : group I (n=47) with aprotinin and group ll (n=48) without aprotinin. Aprotinin was given as one shot injection to cardiopulmonary bypass perfusion solution with dose of 50,000 KIUikg. Laboratory data such as hemoglobin, hematocrit, BUH, creatinine, fibrinogen, electrolyte concentration, aPTT, PT, and AT R was checked preoperatively, 5 minutes after anesthesia, 5 minutes and 35 minutes after CPB circulation, and 5 minutes, 3 hours, and 24 hours after reperfusion. Also, chest-tube drainage, transfused amount of RBC, platelet concentrate, and fresh frozen plasma within first 24 hours postoperatively were checked and analyzed after transition nn body weight demension. Only RBC transfused postoperatively had statistical significance with P value of less than 0.001. Others had no difference statistical wise. Postoperative side effects of aprotinin was not detected weeks after the surgery and there was no reoperated patient due to postoperative bleeding.

• Fire Science and Engineering
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• v.31 no.6
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• pp.1-7
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• 2017

Currently, flammable liquids account for more than 87 wt% of the hazardous materials in circulation in Korea, and paint products are the most commonly used mixed hazardous materials. Therefore, one of the most urgent and important issues is that we have to secure the safety for manufacturing, storage and transport of paint products. In this study we investigated and analyzed the domestic hazardous materials safety management method, the international GHS test method and so forth. We tested risks for a variety of oil paints and found a relation between the results. Furthermore, the risk test method and criteria adapted for domestic situation was presented. Paints were classified as hazardous or non-hazardous according to the results of the flash point test, the amount of flammable liquid or the UN-combustion persistence test. It was revealed from the test results of 6 kind of oil-based paints using different resins that they were hazardous materials with very high risks and belonged to the Category 1 or the Category 2.

• Journal of The Korean Society of Clinical Toxicology
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• v.13 no.1
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• pp.36-39
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• 2015

Copper sulfate is a copper compound used widely in the chemical and agriculture industries. Most intoxication occurs in developing countries of Southeast Asia particularly India, but rarely occurs in Western countries. The early symptoms of intoxication are nausea, vomiting, diarrhea, and abdominal cramps, and the most distinguishable clue is bluish vomiting. The clinical signs of copper sulfate intoxication can vary according to the amount ingested. A 75-year old man came to our emergency room because he had taken approximately 250 ml copper sulfate per oral. His Glasgow Coma Scale (GCS) score was 14 and vital signs were blood pressure 173/111 mmHg, pulse rate 24 bpm, respiration rate 24 bpm, and body temperature $36.1^{\circ}$ .... Arterial blood gas analysis (ABGa) showed mild hypoxemia and just improved after 2 L/min oxygen supply via nasal cannula. Other laboratory tests and chest CT scan showed no clinical significance. Three hours later, the patient's mental status showed sudden deterioration (GCS 11), and ABGa showed hypercarbia. He was arrested and his spontaneous circulation returned after 8 minutes CPR. However, 22 minutes later, he was arrested again and returned after 3 minutes CPR. The family did not want additional resuscitation, so that he died 5 hours after ED visit. In my knowledge, early deaths are the consequence of shock, while late mortality is related to renal and hepatic failure. However, as this case shows, consideration of early definite airway preservation is reasonable in a case of supposed copper sulfate intoxication, because the patients can show rapid deterioration even when serious clinical manifestation are not presented initially.

• Resources Recycling
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• v.26 no.4
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• pp.9-18
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• 2017

Recently, the amount of electronic scrap is rapidly increasing due to the rapid growth of the electronics industry. Among the components of electronic scrap, the printed circuit board(PCB) is an important recycling target which includes common metals, precious metals, and rare metals such as gold, silver, copper, tin, nickel and so on. In Korea, however, PCB recycling technologies are mainly commercialized by some major companies, and other process quantities are not accurately counted. According to present situation, several urban mining companies, research institutes, and universities are conducting research on recovery of valuable metals from PCBs and/or reusing them as raw materials that is different from existing commercialization process developed by major companies. In this study, we analyzed not only current status of collection/disposal process and recycling of waste PCBs in Korea but also the trend of recycling technologies in order to help resource circulation from waste PCBs become more active.