• Journal of Korean Tunnelling and Underground Space Association
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• v.23 no.5
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• pp.359-370
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• 2021

Duct slabs, which are used to build ventilation facilities in underground spaces with transverse ventilation system, need to secure fire resistance according to longitudinal and heavy vehicle traffic of tunnels. This study measured the temperature change at the construction joint of the precast fireproof duct slab which integrates fire resistance material and duct slab under the RWS fire scenario. As a result, it was confirmed that if there is no reinforcement of the construction joint, damage will occur in concrete inside the construction joint, leading to damage to the fireproofing layer. On the other hand, when one side of the construction joint was reinforced with fireproofing materials, it showed more than three times the fire resistance performance compared to when there was no reinforcement. At this time, cross-sectional losses of concrete and fireproofing layer were shown in blocks without reinforcement, but no damage was seen in the reinforced blocks.

• Clinical and Experimental Pediatrics
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• v.57 no.5
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• pp.222-225
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• 2014

Purpose: A recent study analyzing several cytokines reported that long cardiopulmonary bypass (CPB) time and long aortic cross clamp (ACC) time were accompanied by enhanced postoperative inflammation, which contrasted with the modest influence of the degree of hypothermia. In this present study, we aimed to examine the effect of CPB temperature on the clinical outcome in infants undergoing repair of isolated ventricular septal defect (VSD). Methods: Of the 212 infants with isolated VSD who underwent open heart surgery (OHS) between January 2001 and December 2010, 43 infants were enrolled. They were classified into 2 groups: group 1, infants undergoing hypothermic CPB ($26^{\circ}C-28^{\circ}C$; n=19) and group 2, infants undergoing near-normothermic CPB ($34^{\circ}C-36^{\circ}C$; n=24). Results: The age at the time of the OHS, and number of infants aged<3 months showed no significant differences between the groups. The CPB time and ACC time in group 1 were longer than those in group 2 (88 minutes vs. 59 minutes, P =0.002, and 54 minutes vs. 37 minutes, P =0.006 respectively). The duration of postoperative mechanical ventilation was 1.6 days in group 1 and 1.8 days in group 2. None of the infants showed postoperative neurological and developmental abnormalities. Moreover, no postoperative differences in the white blood cell count and C-reactive protein levels were noted between two groups. Conclusion: This study revealed that hypothermic and near-normothermic CPB were associated with similar clinical outcomes and inflammatory reactions in neonates and infants treated for simple congenital heart disease.

• Journal of Korean society of Dental Hygiene
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• v.18 no.3
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• pp.347-358
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• 2018

Objectives: The purpose of this study is to identify the association between oral health status and pulmonary ventilatory defects. Methods: The 6th (2013-2015) National Health and Nutrition Examination Survey data was used. The study subjects were those aged 40-79 who had pulmonary function examination. Complex samples general linear model analysis, Complex samples cross-tabulation analysis, and Complex samples logistic regression analysis were conducted. Results: In terms of restrictive ventilatory defects, the study subjects (8.3%) who recognized that their oral health status was bad outnumbered those who recognized that their oral health status was good (6.1%) (p<0.05). Many of the study subjects who experienced difficulty in biting, chewing and/or speech, and who had an unhealthy periodontal had restrictive ventilatory defects and obstructive ventilatory defects (p<0.05). The association between oral health status and pulmonary ventilatory defects was analyzed. The findings showed that those who had unhealthy periodontal had a 1.33 times higher probability of pulmonary ventilatory defects than those who had a healthy periodontal (p<0.05). After taking into account general characteristics (age, sex, incomes, education, and smoking) of the subjects, the association between oral health status and pulmonary ventilatory defects was analyzed. The result found that only in cases where one experienced dental caries was an association with pulmonary ventilatory defects found. In other words, those who had dental caries showed a 0.73 times higher probability of pulmonary ventilatory defects than those who had no dental caries (p<0.05). Conclusions: Based on the findings of this research, oral health status was found to be associated with pulmonary ventilatory defects. To improve oral health, it is necessary to provide life-cycle stages based oral health education. Therefore, it is required to develop an oral health education program and develop a national oral health policy.

• Safety and Health at Work
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• v.7 no.4
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• pp.317-321
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• 2016

Background: This study was conducted with aim of providing an overview of the current status of occupational health services and identifying the most common harmful agents at workplaces of Iranian self-employed enterprises (Nano-Scale Enterprises). Methods: A cross-sectional study was performed among a random sample including 1,758 employees engaging in self-employed enterprises with 5 and less employees. Results: Coverage of occupational health surveillance was very poor, annual health examinations were been conducted only for 64 (3.64%) of males and 31 (1.76%) of females, and occupational health trainings were not included of the services at all. Personal Protective Equipment were available in 462 (26.3%) of the enterprises. only in 0.4% of the enterprises working processes were been equipped by a local exhaust ventilation system. Difficult postures were the most common (81.5%) adverse working conditions. Conclusion: This study revealed a poor level of the implementation of occupational health services in Iranian self-employed enterprises. Based on the findings, providing basic training on the occupational health, more enforcing in conduction of health examinations and providing PPE, and taking appropriate strategies aimed at eliminating or minimizing work environment harmful agents are the major factor that should be considered to improve the level of occupational health services among the studied enterprises.

• Culinary science and hospitality research
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• v.20 no.5
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• pp.43-51
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• 2014

The purpose of this study is to assess the sanitation level and purchase behavior of fishery products, and to identify management conditions of bad smell from cooking fish at home as perceived by housewives in a metropolitan area. Frequency analysis, descriptive analysis, and cross-tabulation analysis were employed as statistical techniques for current study. Total 270 were collected from housewives. The statistical variables included the kinds of cooking oil and the age of housewives, the types of hoods for fish roasting, the types of covers for fish grills, the number of family, the ventilation methods, and the maintenance of kitchen utensils based on family incomes, and they showed statistically significant differences(p<.05). Furthermore, the housewives whose sanitary cognition level for fishery products was high, the housewives whose level of purchase attitude was relatively high, and the housewives who utilized specialized kitchen utensils demonstrated statistically significant differences(p<.05). It resulted from the assessment of such actual conditions as difference of culinary environment according to the sanitation level of fishery products, the level of purchase attitude, and whether the housewives utilized special kitchen utensils or not. The more efforts were proved from those who had the intentions for improvement of an amenable culinary environment at homes, according to the higher income obtainers, the smaller nuclear family, the younger generation, whether the housewives utilized special kitchen utensils or not, and those who had the higher sanitary cognition level of fishery products. The above results were derived from an individual lifestyle or a dietary lifestyle, but eventually this seems to be related with the propensity and values hierarchy of individuals.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.9
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• pp.787-797
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• 2011

The noise in a vehicle is an important factor for customers purchasing a car. Particularly, reduction of the noise that is generated from HVAC(heating, ventilation and air conditioning) is very important since it has considerable effects on interior noise. In general, identification of noise source is crucial to reduce noise level. The complex acoustic intensity method is widely used to obtain the accurate measurement and identification of noise source. Therefore, in the previous study, noise source of HVAC was identified through experimental approach using the complex acoustic intensity method. In this study, we are intended to confirm reduced level of noise by comparing the result between before and after modification of cam curve that is based on identified noise source of HVAC. It is found out that noise source of HVAC are motor and cam area using the complex acoustic intensity method in the previous study. We performed experiments to compare noise level between before and after modification of cam curve. Especially, it can be seen that complex acoustic intensity method using both active and reactive intensity is vital in devising a strategy for comparison to noise level. Also, the vector flow of acoustic intensity was investigated to identify sound intensity distributions and energy flow in the near field of HVAC.

• Journal of the Korean Society for Railway
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• v.12 no.1
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• pp.25-30
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• 2009

The present study deals with numerical investigation for smoke behavior in rescue station by using the commercial CFD code (FLUENT Ver 6.3). With the use of the MVHS(Modify Volumetric Heat Source) model modified from the original VHS(Volumetric Heat Source) model, a 10 MW mode was adopted for simulation and the MVHS model can describe the generation of product and the oxygen consumption at the stoichiometric state. In addition, the present simulation includes the species conservation equations for the materialization of heat source and the estimation of smoke movement. From the results, the smoke flows are moving along the ceiling because of thermal buoyancy force and as time goes, the smoke gradually moves downward at the vicinity of the entrance. Moreover, without using ventilation, it is found that the smoke flows no longer spread across the cross-passages because the pressure in the non-accident tunnel is higher than that in the accident tunnel.

• Journal of Chest Surgery
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• v.10 no.1
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• pp.133-139
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• 1977

Two cases of congenital aneurysm of sinus of Valsalva, ruptured into the right ventricle, and associated with ventricular septal defects, were undergone intracardiac repair with the aid of extracorporeal circulation using Bentley bubble oxygenator and moderate hypothermia. Case 1. A 20 year old male, with the chief complaints of palpitation and dyspnea, was admitted to Kyungpook National University Hospital on Dec. 16, 1976. Continuous machinery murmur was heard best at left 3rd. intercostal space along the sternal border. Retrograde aortography disclosed aneurysm of the right coronary cusp, which ruptured into the right ventricle. Utilizing cardiac bypass and moderate hypothermia, the right ventricle was opened and aneurysm was closed by direct sutures. Associated ventricuar septal defect was directly ,closed and suture line was reinforced by Dacron patch. Total bypass time was 112 minutes and total aortic cross clamping time was 37 minutes. Assist ventilation was carried out for 28 hours postoperatively. His postoperative course was smooth except removal o1 substernal hematoma and he was .discharged on 24th postoperative day. Case 2. A 28 year old man was admitted to our Hospital on June 9, 1976. two weeks prior to this admission, suddenly he had collapsed while he was walking on the street. Following `this episode, palpitation, dyspnea on exertion and frequent respiratory infection developed. Grade IV systolic murmur was heard best at 3rd intercostal space along the sternal border. Retrograde aortography confirmed the diagnosis of rupture of aneurysm of the sinus Valsalva ruptured into the right ventricle. Under the cardiopulmonary bypass the right ventricle was opened and ruptured aneurysm and infracristal ventricular septal defect were directly closed and reinforced with Dacron patch. Postoperative course was uneventful and he was discharged on 14th postoperative day. The pathogenesis of aneurysm of the sinus Valsalva and mode of diagnosis were discussed. Principle of surgical repair was presented.

• Fire Science and Engineering
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• v.23 no.4
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• pp.13-18
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• 2009

The main objective of the present study is to investigate smoke propagation in railway tunnels with rescue stations. In particular, based on measurement of HRR (heat release rate) for pool fires formed at different locations, the influence of fire source location on smoke behavior is examined. The fuel is n-heptane and pool fires are generated with a square length 4cm. With the use of MVHS (Modified Volumetric Heat Source) model for fire source, extensive numerical simulations are performed by using the commercial code FLUENT (Ver.6.3) Predicted smoke temperatures and smoke propagation are discussed. From numerical predictions, it is found that ventilation systems may be necessary in the railway tunnels because the smoke moves along the tunnel, and consequently it enters the non-accident tunnel. It is also confirmed that the cross-passage and fire protection wall systems contribute to control the smoke.

• Journal of The Korea Institute of Healthcare Architecture
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• v.24 no.2
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• pp.37-44
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• 2018

Purpose: This study investigates the influences of coughing direction and healthcare worker's location on the transport characteristics of coughed particles in airborne infection isolation room (AIIR), which is commonly called negative pressure isolation room, with a downward ventilation system. Methods: Computational Fluid Dynamics (CFD) was used to simulate the airflow and for tracing the behavior of particles. Results: The results show that the airflow pattern and coughing direction have a significant influence on the characteristics of particle dispersion and deposition. When healthcare workers are in the isolation room with the patient who is lying on the bed, it is recommended to be located far from the anteroom to reduce the exposures from infectious particles. And when the patient is lying, it is more effective in removing particles than when the patient is in Fowler's position. Although it is an isolation room that produces unidirectional flow, coughing particles can spread to the whole room and a large number of particles can be deposited onto patient, bed, side rails, healthcare worker, ceiling, floor, and sidewall. Implications: Following the patients' discharge or transfer, terminal cleaning of the vacated room, furniture, and all clinical equipment is essential. Also, it is necessary to establish detailed standard operating procedure (SOP) in order to reduce the risk of cross-contamination.