• Journal of the Korean Society of Costume
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• v.58 no.1
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• pp.90-103
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• 2008

This study aims to examine the current state of wearing working clothes for the workers who work in Electric Technology Division, Korea Railroad Corporation, to identify inconveniences and problems in relation to the working clothes, and based on the examination, to find a way to improve them, creating a design of summer working clothes that will have more advanced functionalities including activity adaptability and comfort. Survey was conducted through direct observation and interview for Electric Railway Power Team. A total of 352 copies were collected and analyzed. Based on the results of questionnaire, an experimental clothes, the functionality of which has improved in terms of design, material, and patterns, was created. The followings are the results of the study. Easy activity, design, and comfort are required as functions of working clothes. In design related questions, the survey shows high dissatisfaction in the color of existing working clothes, and preferred colors are dark blue and gray. With regard to the method of zipping up the front side, zippers are preferred. Although many pockets on the existing working clothes have high satisfaction, dissatisfaction to pocket format is high. In material related questions, lower dissatisfaction is indicated for the sense of touch, ventilation and sweat absorption. It is shown that the areas frequently polluted include the lower part of pocket, the edges of sleeves and elbow areas on the jacket. The frequently polluted area of the trousers include knee areas, the edges of pants and buttocks. With regard to the areas where the workers felt discomfort when motion, discomfort is highly indicated with armpits and back on the jacket. Also discomfort is highly indicated with crotch, buttocks and knee areas on the trousers. In material related questions, lower dissatisfaction is indicated for the sense of touch, ventilation, sweat absorption.

• Research in Community and Public Health Nursing
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• v.15 no.2
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• pp.289-297
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• 2004

Purpose: This study was conducted to determine factors affecting workers' physiological somatic complain using the Job Stress Model proposed by the National Institute for Occupational Safety and Health (NIOSH). Method: Data were collected from the 1st to the 30th of December 1999. The subjects were 2.123 workers employed at 155 work sites. Collected date were analyzed through SAS/PC program. Result: According to individual characteristics, younger and women groups showed significantly higher physiological somatic complaint than elder men groups. By work condition, groups with higher physiological somatic complaint included workers of irregular shift work. Dark lighting, improper temperature in winter, improper ventilation, inappropriate humidity, unpleasant work environment and crowded work place were significantly related with physiological somatic complaint. By work-related factor, physiological somatic complaint was high in those with higher variance in work load, quantitative work load, role conflict, job burden, role ambiguity and future ambiguity. On the other hand, physiological somatic complaint was low in those with little underutilization of ability. As for the relationships between physiological somatic complaint and non-work related factors, physiological somatic complaint was high in workers who had a side job, were bringing up infants alone, cleaned the house alone, cared for the elderly and disabled persons, were studying, were volunteering at another organization, and were spending 5-10 hours in religious activities per week. Physiological somatic complain was in significantly negative correlations with overall social support, supervisory support and family support, but in significantly positive correlations with co-worker support. Conclusion: The main predictors of physiological somatic complain were gender, shift work pattern, overtime work, ventilation, role ambiguity, role conflict, future ambiguity, job control, variance in work load, overall social support, worker with side job, worker who cleans the house alone, worker who is studying. These predictors explained 19.10% of the total variance of physiological somatic complain.

• Journal of the Korean Society of Safety
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• v.20 no.1 s.69
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• pp.36-41
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• 2005

PCV(Positive Crankcase Ventilation) valve acts as a flow control valve to get a re-combustion of blow-by gas by having it flow from a crankcase to an inlet manifold suction tube. The blow-by gas of the crankcase should be eliminated or taken properly because it cause corrosion to critical parts, and contributes to increase crankcase pressure that can cause a drop in efficiency. The excessive stress and strain on the PCV valve that remove these harmful gas would be bring the difficult on the flow rate control and failure of the valve. Those condition inevitably induce the accident. Therefore, this study purpose is FEM evaluation of the stresses and deformation in the X3 PCV model according to the change of the differential pressure between inlet and outlet. From results, the maximum equivalent stresses increased linearly according to the increase of the differential pressure at the about 50mm from the inlet position and were under the yield strength of the valve. And the deformations were relatively small regardless of the in-outlet differential pressure variation.

• Journal of the Korean Society of Propulsion Engineers
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• v.18 no.4
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• pp.81-89
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• 2014

Tandem-ejector has been devised for engine-bay cooling. In this study, 1-D model has been developed to analyze Tandem-ejector. In the model, the primary, the secondary and the tertiary flow conditions have been analyzed with isentropic process. The mixing process has been analyzed with conservation laws based on the control volume analysis. The total pressure loss of the primary flow has been analyzed under the matching condition between the static pressure of Tandem-ejector discharge flow and atmospheric pressure. Consequently, 1-D model can predict Tandem-ejector performance accurately and provide the performance map.

• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.6
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• pp.135-144
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• 2013

Ventilation efficiency has an important role in agricultural facilities such as greenhouse and livestock house to keep internally optimum environmental condition. Age-of-air concept allows to assess the ventilation efficiency of an agricultural facility according to estimating the ability of fresh air supply and contaminants emission using LMA and LMR. Most of these methods use a tracer gas method which has some limitations in experiment like dealing unstable and invisible gas. Therefore, the aim of this study was to develop a straightforward method to calculate age-of-air values with CFD simulation which has the advantage of saving computational time and resources and these method can solve the limitations in experiment using tracer gas method. The main idea of LMA computation is to solve the passive scalar transport equation with the assumption that the production of the time scalar throughout the room is uniform. In case of LMR calculation, the transport of the time scalar was reversed compulsively using UDF. The methodology to validate the results of this study was established by comparing with preceding research that had performed a computing LMA and LMR value by laboratory experiments and CFD simulations using tracer gas. As a result, the error was presented similarly level of results of preceding research. Some big errors could be caused by stagnated area and incongruity turbulence model. while the computational time was reduced to almost one fourth of that by preceding research.

• Korean Journal of Medicinal Crop Science
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• v.4 no.1
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• pp.58-63
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• 1996

This experiment was carried out to elucidate the effect of the rain shelter and insect net on the growth and yield in Lycium chinense 'Cheongyang Cultivar'. The yield cultivated at the condition of the rain shelter and insect net were increase $92{\sim}106$ percent as that of nature conditions resulted from better growth and decrease of fruit attacked by anthracnose and injured by Eriophyes kuko. It had not significant between the ventilation and non-ventilation.

• Nuclear Engineering and Technology
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• v.54 no.11
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• pp.4195-4208
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• 2022

In this study, operator habitability was numerically evaluated in the event of a fire at the main control bench board (MCB) in a reference main control room (MCR). It was investigated if evacuation variables including hot gas layer temperature (HGLT), heat flux (HF), and optical density (OD) at 1.8 m from the MCR floor exceed the reference evacuation criteria provided in NUREG/CR-6850. For a fire model validation, the simulation results of the reference MCR were compared with existing experimental results on the same reference MCR. In the simulation, various input parameters were applied to the MCB panel fire scenario: MCR height, peak heat release rate (HRR) of a panel, number of panels where fire propagation occurs, fire propagation time, door open/close conditions, and mechanical ventilation operation. A specialized-average HRR (SAHRR) concept was newly devised to comprehensively investigate how the various input parameters affect the operator's habitability. Peak values of the evacuation variables normalized by evacuation criteria of NUREG/CR-6850 were well-correlated as the power function of the SAHRR for the various input parameters. In addition, the evacuation time map was newly utilized to investigate how the evacuation time for different SAHRR was affected by changing the various input parameters. In the previous studies, it was found that the OD is the most dominant variable to determine the MCR evacuation time. In this study, however, the evacuation time map showed that the HF is the most dominant factor at the condition of without-mechanical ventilation for the MCR with a partially-open false ceiling, but the OD is the most dominant factor for all the other conditions. Therefore, the method using the SAHRR and the evacuation time map was very useful to effectively and comprehensively evaluate the operator habitability for the various input parameters in the event of MCB fires for the reference MCR.

• Journal of Chest Surgery
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• v.56 no.2
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• pp.128-135
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• 2023

Background: Pneumonia caused by severe acute respiratory syndrome coronavirus 2 can cause acute respiratory distress syndrome, often requiring prolonged mechanical ventilation and eventually tracheostomy. Both procedures occur in isolation units where personal protective equipment is needed. Additionally, the high bleeding risk in patients with extracorporeal membrane oxygenation (ECMO) places a great strain on surgeons. We investigated the clinical characteristics and outcomes of percutaneous dilatational tracheostomy (PDT) in patients with coronavirus disease 2019 (COVID-19) supported by ECMO, and compared the outcomes of patients with and without ECMO. Methods: This retrospective, single-center, observational study included patients with severe COVID-19 who underwent elective PDT (n=29) from April 1, 2020, to October 31, 2021. The patients were divided into ECMO and non-ECMO groups. Data were collected from electronic medical records at Ajou University Hospital in Suwon, Korea. Results: Twenty-nine COVID-19 patients underwent PDT (24 men [82.8%] and 5 women [17.2%]; median age, 61 years; range, 26-87 years; interquartile range, 54-71 years). The mean procedure time was 17±10.07 minutes. No clinically or statistically significant difference in procedure time was noted between the ECMO and non-ECMO groups (16.35±7.34 vs. 18.25±13.32, p=0.661). Overall, 12 patients (41.4%) had minor complications; 10 had mild subdermal bleeding from the skin incision, which was resolved with local gauze packing, and 2 (6.9%) had dislodgement. No healthcare provider infection was reported. Conclusion: Our PDT approach is safe for patients and healthcare providers. With bronchoscopy assistance, PDT can be performed quickly and easily even in isolation units and with acceptable risk, regardless of the hypo-coagulable condition of patients on ECMO.

• 보존과학연구
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• s.22
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• pp.155-171
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• 2001

The facilities of exhibition and collection for cultural properties is affected by environmental pollution. In order to accumulate a store of basic data, we was investigated eight points(three points at exhibition room and five points at collection room) at four institutes, from December 2000 to March 2001.As a result of investigation, the temperature of A-Exhibition room measured low because of don’t moved HVAC(Heating, Ventilation and Air-Conditioning) System, B Exhibition room is dry for the effect of air-conditioner and the air pollutants concentration of C-Exhibition room is high for the kind of an exhibition room. The air-condition was varied within the open period. The air pollutants concentration of A-Collection room is measured high because the air-pollutants is generated in a new buildings and the air pollutants concentration of C-1 & C-2-Collection room is high for the kind of an collection room. It is necessary to ventilate sufficiently.

• KIEAE Journal
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• v.15 no.1
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• pp.5-12
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• 2015

Recently, natural disasters have unexpectedly occurred at various places in the world and the countermeasure of them become the social issues. Many of victims in disasters need temporary residential facilities above all things and many of researches have been conducted in order to develop simple, safe, and economic designs of them. Moreover, indoor thermal comfort and air quality must be considered in the facilities against a disaster, because clean and healthy space should be provided to the suffered victims. In this research, in order to estimate the indoor environment of the developed modular building for disaster preparation, CFD simulation was conducted in the various condition. In this paper, indoor air quality such as the age of air, the concentration of $CO_2$ was estimated by the case study