• Fire Science and Engineering
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• v.25 no.1
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• pp.34-41
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• 2011

This research examines problem that can happen in partial smoke control method among contiguity area smoke control system through engineering examination and CFD. And the ultimate purpose of this is to secure safety of a person inhabiting at fire department by presenting improvement plan. Now a days, in large space-area such as department store or mega-mall in which mainly applies "Partial Smoke Control Method", air is suppled from adjacent area and smoke is exhausted in fire room. For various reason, however, it is confirmed through simulation that if air is suppled in one direction, this can cause a fatal result to people of fire area because of the difficulty in securing the evacuation time. As an improvement plan, air is supplied at the same time in surroundings to fire department.

• Journal of Korean Tunnelling and Underground Space Association
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• v.8 no.1
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• pp.53-63
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• 2006

The objective of this study is to analyze the smoke movement and the smoke extraction efficiency using by the partial extraction system for case of tunnel fire. Based on Froude modeling and isothermal model, the 1/20 scaled model tunnel (12m long) was constructed. In the case of the upper critical velocity in the main tunnel, the smoke extraction efficiency shows almost same between group damper and distributed damper. Finally, if the fire occurs on a traffic Jam in a tunnel, it is proposed that the open dampers in partial gallery extract smoke from the main tunnel without jet fan operation. Then, after the passengers have escaped the tunnel, the jet fans work on. On the other hand, If the traffic is uncongested in the tunnel, the jet fans (smoke control system) and partial extraction system (smoke exhaust system) are operated at once in tunnel fire.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.11a
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• pp.96-97
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• 2019

According to building law, there are only regulations on the fire prevention compartments that can perform the function of partial smoke compartment, but the building law management of the smoke compartment for effective smoke diffusion prevention and control is not possible. The lack of control on the smoke compartment such as leakage rate on the penetrating part, and the lack of leakage rate in the design of smoke control of fire safety law resulted in the absence of fundamental safety technology. Therefore, this study seeks to find solutions to domestic problems after reviewing relevant domestic laws and regulations.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.6
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• pp.151-158
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• 2007

The static and dynamic behaviour of VGT and EGR systems has a significant impact on overall engine performance, fuel economy and exhaust emissions. This is because they define the state and composition of the air charge entering the engine. This work focused on the effect of the aperture ratio of VGT and EGR on the emission and flow characteristics under partial loads conditions. The investigation carried out using 2 liter PCCI 4 cylinder diesel engine with VGT and EGR. The result of this study shows that smoke increases with increasing EGR rate and NOx decreases with increasing EGR rate. It was also found that the residual gas contents greatly impact on soot emission under partial load condition. Finally, it can be concluded that VGT and EGR aperture ratio can greatly impact not only on soot and NOx but also air charging.

• Journal of the Korean Society of Tobacco Science
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• v.31 no.1
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• pp.29-38
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• 2009

Although prion diseases, a group of fatal neurodegenerative diseases of human and animals, are presumed to be caused by several mechanisms including abnormal change of prion protein, oxidative stress is still believed to play a central role in development of the diseases. Cigarette smoking has a few beneficial effects on neuronal diseases such as Alzheimer's disease and Parkinson's disease despite of many detrimental effects. In this study, we investigated how chronic cigarette smoking could exert such beneficial effect against oxidative damage. For this study, homogenates of 87V scrapie-infected brain was inoculated on intracerebral system of IM mice through stereotaxic microinjection and biochemical properties concerning with oxidative stress were examined. The scrapie infection decreased the activity of mitochondrial Mn-containing superoxide dismutase by 50% of the control, meanwhile the effects on other antioxidant enzymes including Cu or Zn-containing superoxide dismutase were not significant. Additionally, the infection elevated superoxide level as well as monoamine oxide-B (MAO-B) in the infected brain. Interestingly, many of the detrimental effects were improved in partial or significantly by long-term cigarette smoke exposure (CSE). CSE not only completely prevented the generation of mitochondrial superoxide but also significantly (p<0.05) decreased the elevated mitochondrial MAO-B activity in the infected brain. Concomitantly, CSE prevented subsequent protein oxidation and lipid peroxidation caused by scrapie infection; however, it did not affect the activities of antioxidant enzymes. These results suggest that chronic exposure of cigarette smoke contribute to in part preventing the progress of neurodegeneration caused by scrapie infection.

• Yonsei Medical Journal
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• v.59 no.9
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• pp.1079-1087
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• 2018

Purpose: Obstructive sleep apnea and chronic obstructive pulmonary disease are independent risk factors of cardiovascular disease (CVD), and their coexistence is known as overlap syndrome (OS). Endothelial dysfunction is the initial stage of CVD; however, underlying mechanisms linking OS and CVD are not well understood. The aim of this study was to explore whether OS can lead to more severe inflammation and endothelial apoptosis by promoting endothelial dysfunction, and to assess the intervention effects of antioxidant tempol. Materials and Methods: Male Wistar rats (n=66) were exposed to normal oxygen [normal control (NC) group], intermittent hypoxia (IH group), cigarette smoke (CH group), as well as cigarette smoke and IH (OS group). Tempol intervention was assessed in OS group treated with tempol (OST group) or NaCl (OSN group). After an 8-week challenge, lung tissues, serum, and fresh blood were harvested for analysis of endothelial markers and apoptosis. Results: The levels of intracellular adhesion molecule-1, vascular cellular adhesion molecule-1, and apoptosis in circulating epithelial cells were the highest in OS group and the lowest in NC group. These levels were all greater in IH group than in CH group, and were lower in OST group than in OS and OSN groups (all p<0.001). Conclusion: Synergistic effects of IH with cigarette smoke-induced emphysema produce a greater inflammatory status and endothelial apoptosis. OS-related inflammation and endothelial cell apoptosis may play important roles in promoting cardiovascular dysfunction, and antioxidant tempol could achieve a partial protective effect.

• Journal of Ginseng Research
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• v.19 no.3
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• pp.225-230
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• 1995

The effect of long-term ginseng (Panax ginseng C.A. Meyer) administration on the clearance of carboxyhemoglobin (CO-Hb) and the property of blood gases was investigated in rats. Rats were received ginseng water extract (0.025% in drinking water) for 42 weeks starting at the age of 6 weeks. They were exposed to the diluted mainstream smoke generated from 15 filter cigarettes for 20 min in a round polycarbonate chamber (D37 cmXH13 cm). Under this condition, the mean CO-Hb content of control and the ginseng-treated rats immediately after the exposure was nearly the same as 13.8$\pm$2.9 f) and 13.9$\pm$1.6%, respectively. However, CO-Hb was more rapidly removed from blood in the ginseng treated rats than in untreatEd control with the laps of time, namely, its biological half life In the former was 36.9$\pm$1.5 min and in the latter was 56.9$\pm$13.2 min. Although long-term ginseng treatment did not affect the content of hemoglobin and blood pH of rats, it slightly increased blood oxygen content and its partial pressure value, and decreased levels of carbon dioxide and bicarbonate. These results suggest that long-term administration of rats with ginseng extract accelerate the elimination of CO from the blood. This effect seems to be related to the enhancement of oxygen consumption of the rat by a certain action of ginseng components as previously reported.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.6
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• pp.88-96
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• 2008

Currently, due to the serious world-wide air pollution by substances emitted from vehicles, emission control is enforced more firmly and it is expected that the regulation requirements for emission will become more severe. A new concept combustion technology that can reduce the NOx and PM in relation to combustion is urgently required. This study used a split injection method at a 4 cylinder common-rail direct injection diesel engine in order to apply the partially premixed charge compression ignition combustion method without significantly altering engine specifications And it is investigated that the effects of the injection ratio and SCV(swirl control valve) to emission characteristics. From these tests, soot(g) and NOx(g) emission could be reduced to 40% and 92% compared to base engine performance at specified engine driving conditions(6 points with weight factors) according to application of split injection and SCV(swirl control valve).

• Journal of Advanced Marine Engineering and Technology
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• v.41 no.4
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• pp.362-367
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• 2017

This study was conducted to compare the particulate removal efficiency of the developed diesel particulate filter using various measurement methods in a high-speed marine diesel engine. A four-stroke mechanical marine diesel engine is used for the test, which has a maximum output of 403 kW and is coupled to an AC dynamometer to control engine speed and load. The test was conducted based on four steady-state engine operating conditions of E3 engine test cycle for the measurement of PM and soot removal efficiency using partial dilution method considered as gravimetric method and filter smoke number method as light absorption method, respectively. As a result of the removal efficiency measurement according to the application of diesel particulate filter, particulate matter was reduced from 76% to 91% and the soot was reduced by more than 90% while meeting the permissible engine back pressure. From these results, the applicability of diesel particulate filter adopted in high-speed marine diesel engines could be confirmed. In addition, based on the result that the particulate removal efficiency varies with different measurement methods, the necessity of unification of these methods could be identified.