• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.748-753
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• 2008

In modern buildings, the air-tightness and insulation for energy saving resulted in degradation of Indoor Air Quality(IAQ). It has brought out new diseases such as New Building Syndrome(NBS) and Sick Building Syndrome(SBS) to the tenants of such buildings. As a result, researches on the Dynamic Breathing Building(DBB) are being undertaken to minimize energy loss as well as to improve IAQ. DBB is a state-of-the-art technology to build channels inside the wall so that air migrates between indoor and outdoor, which improves insulation performance and IAQ. This study attempts to evaluate the improvement of DBB employed in real buildings. As analyzing tools, IAQ improvement and particle degradation while were evaluated while the required indoor ventilation rate was satisfied. DBB were installed in the twin test cells at Korea Institute of Energy Research(KIER). From the test, IAQ was compared with outdoor air base on the concentration of particle matter(PM10). As a results, the concentration of particle dust (PM10) within the breathing walls was reduced by 80% at 0.7 ACH, 67% at 2 ACH, 63% at 3 ACH respectively. As ACH is higher, Dnamic Isulation(DI) and normal wall permit more PM10 particles being infiltrated.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.2101-2108
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• 2008

Most of train fires which occur in usual cases do not grow up significantly on a large scale enough to bring about casualties and harmful damages. However, the consequence of some train fire accidents can be devastating disaster so that it would be even recorded in history in unusual cases. Accordingly, such a probability of fire disaster cannot be ignored in aspect of the railway safety assesment. A scale of injury and damage is very difficult to predict and analyze. Because it is depend on various factors, i.e. fire load, burning period, facilities, environment condition, and so on. Thus, a prediction of fire load could be understood as a one methodology to estimate railway safety assesment. The summation method which is one of them is used to evaluate the overall fire load by assuming that sum of heat release rate per unit area or mass of each composite material equals the total. However, since the train fire is classified into a compartment fire in under-ventilation condition. The summation method do not estimate a fire load completely. In this journal, Various methods to predict fire load are introduced and evaluated. Especially the fire simulation tool FDS(Fire Dynamics Simulator)which is based on the CFD(Computational Fluid Dynamics) is introduced, too. Through the FDS simulation, numerical analyses for the fire load and flame spread are performed. Then, these results of the simulation are validated through the comparison study with the experimental data. Then, limitations and approximations including in simulation process are discussed. The future direction of research is proposed.

• Fire Science and Engineering
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• v.34 no.4
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• pp.59-68
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• 2020

In this study, the authors designed a reduced-scale railway vehicle fire, which was necessary for evaluating the fire safety of railway tunnels using a reduced model. To overcome the shortcomings of the methods used in conventional reduced-scale railway tunnel tests, the authors simulated the fire source of a railway vehicle using a methanol fire source for fire buoyancy, and a smoke cartridge for smoke visualization. Therefore, the heat release mass consumption rates of various methane trays were measured using a cone calorimeter (ISO 5660). The critical ventilation velocity in the railway tunnels was obtained using the designed fire source of the railway vehicle, which was evaluated by the measured temperature at the top of the tunnel as well as laser visualization.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.6
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• pp.833-839
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• 2013

Cardiopulmonary resuscitation (CPR) is performed by thoracic compression and artificial ventilation for the patient under emergent situation to maintain at least the minimum level of respiration and blood circulation for life survival. Good quality CPR requires monitoring respiration, however, traditional respiratory air flow transducers cannot be used because the transducer elements are facing the whole area perpendicular to the flow axis. The present study developed a new air flow transducer conveniently applicable to CPR. Specially designed "sensing rod" samples the air velocity at 3 different locations of the flow cross-section, then transforms into average dynamic pressure by the Bernoulli's law. The symmetric structure of the sensing holes of the sensing rod enables bi-directional measurement simply by taking the difference in pressure by a commercial differential pressure transducer. Both inspiratory and expiratory flows were obtained with symmetric measurement characteristics. Quadratic curve fitting provided excellent calibration formula with a correlation coefficient>0.999 (P<0.0001) and the mean relative error<1%. The present results can be usefully applied to accurately monitor the air flow rate during CPR.

• 한국태양에너지학회:학술대회논문집
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• 2009.11a
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• pp.205-210
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• 2009

Generally, the building's windows and ventilation for the purpose of mining and the vista and windows by emotional engineering design area is a growing trend. According to the flow of energy is lost from the building, will be achieved through the walls and roof and windows. Among these, the window through the loss of about 45% of the entire building is big enough to rate. In addition, the building regulation U-value Limitation of window is $3.3W/m^2$ K in southern regions, while U-value Limitation of wall is $0.35{\sim}0.58W/m^2$ K. It means that the energy loss through windows is six times more than it through wall. Therefore, the purpose of this study is to evaluate the environmental performance of the super window system by verification experiment. The results of this study are as follows; 1)Thermal performance of insulated Super Window measured as $1.44W/m^2$ $^{\circ}C$ 2)Required energy for heating was cut down about 5.3% from 266.99 $MJ/m^2$ yr to 252.85 $MJ/m^2$ yr 3)Super Window's reduction rates increased 4.1% from 31.48% to 35.58% when it is compared to normal windows. 4)Building energy efficiency rating elevated from 2nd rating to 1st rating.

• Animal Bioscience
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• v.34 no.11
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• pp.1766-1775
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• 2021

Objective: The oxidative stress status and changes of chicken ovary tissue after shading were studied, to determine the mechanism of the effect of shading on follicular development. Methods: Twenty healthy laying hens (40 weeks old) with uniform body weight and the same laying rate were randomly divided into two groups (the shading group and normal light group). In the shading group, the cage was covered to reduce the light intensity inside the cage to 0 without affecting ventilation or food intake. The normal lighting group received no additional treatment. After 7 days of shading, oxidative stress related indicators and gene expression were detected. Results: Analysis of paraffin and ultrathin sections showed that apoptosis of ovarian granulosa cells (GCs) increased significantly after light shading. Enzyme linked immunosorbent assay results revealed that the levels of total antioxidant capacity, malondialdehyde, superoxide dismutase (SOD), glutathione, catalase (CAT), and other substances in the sera, livers, ovaries, and follicular GCs of laying hens increased significantly after shading for 7 days; and reactive oxygen species (ROS) levels in the livers of laying hens also increased significantly. ROS in the serum, ovarian and GCs also increased. After shading for 7 days, the levels of 8-hydroxy-2 deoxyguanosine in the sera and ovarian tissues of laying hens increased significantly. Cell counting kit-8 detection showed that the proliferation activity of GCs in layer follicles decreased after shading for 7 days; the expression level of the anti-apoptotic gene B-cell lymphoma-2 in ovarian tissue and follicular GCs was significantly reduced, and the expression levels of pro-apoptotic caspase 3 (casp3), and SOD, glutathione peroxidase 2 (GPX2), and CAT were all significantly increased. Conclusion: Oxidative stress induced by shading light has a serious inhibitory effect on follicular development during reproduction in laying hens.

• Wind and Structures
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• v.29 no.4
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• pp.235-246
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• 2019

Wind loading is one of important loadings that should be considered in the design of large hyperbolic natural-draught cooling towers. Both external and internal surfaces of cooling tower are under the action of wind loading for cooling circulating water. In the previous studies, the wind loads on the external surface attracted concernedly attention, while the study on the internal surface was relatively ware. In the present study, the wind pressure on the internal surface of a 220 m high cooling tower is measured through wind tunnel testing, and the effect of ventilation rate of the packing layer on internal pressure is a major concern. The characteristics of internal wind pressure distribution and its effect on wind-induced responses calculated by finite element method are investigated. The results indicate that the wind loading on internal surface of the cooling tower behaves remarkable three-dimensional effect, and the pressure coefficient varies along both of height and circumferential directions. The non-uniformity is particularly strong during the construction stage. Analysis results of the effect of internal pressure on wind-induced responses show that the size and distribution characteristics of internal pressure will have some influence on wind-induced response, however, the outer pressure plays a dominant role in the wind-induced response of cooling tower, and the contribution of internal pressure to the response is small.

• Korean Journal of Poultry Science
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• v.47 no.4
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• pp.199-210
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• 2020

Footpad dermatitis (plantar surface footpad lesions) is an increasing problem in the global poultry industry, affecting foot quality, overall welfare, and production performance. The growing consumer demand for chicken feet in Asian markets has given poultry companies interest in reducing footpad dermatitis. The lesions are multiply associated with various factors affecting the moisture content of litter such as nutrition, drinker type and management, environmental conditions (e.g., temperature, relative humidity, ammonia levels, ventilation rate), and flock health. This review addresses footpad dermatitis characteristics, causes, and the assessment system to provide a guide for future research.

• Korean Journal of Clinical Pharmacy
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• v.30 no.4
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• pp.270-278
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• 2020

Background: Although the identification of clinical and laboratory features in pediatric COVID-19 patients is essential in establishing an appropriate treatment plan, a systematic review and meta-analysis on the topic has yet to be reported. Methods: We searched MEDLINE, Embase, and Web of Science to access clinical and laboratory characteristics as well as clinical outcomes of children with COVID-19 infection. A meta-analysis using random-effect model was performed to estimate pooled prevalence and 95% confidence intervals. Results: Among the 532 studies initially collected, 12 articles were finally included in the meta-analysis. Among the investigated 320 pediatric patients with COVID-19, fever (48.2%) and cough (39.3%) were the most common symptoms. Almost one third of patients (30.4%) were asymptomatic. In laboratory findings, only 11.4% of pediatric patients experienced lymphocytopenia. Increased inflammatory markers including c-reactive protein (18.6%) and procalcitonin (32.4%) were observed. Only a few patients needed mechanical ventilation and intensive care support, and only one death was reported. Conclusion: Pediatric patients with COVID-19 infection exhibited milder symptoms and more favorable outcomes compared to adults. However, considering the high rate of asymptomatic pediatric patients, close monitoring is required to prevent community infection in asymptomatic conditions and hidden disease progression.

• Fashion & Textile Research Journal
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• v.22 no.6
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• pp.862-872
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• 2020

This study explores the effects of facemasks on respiratory, thermoregulatory, cardiovascular responses during exercise on a treadmill and at rest. Five male subjects (25.8 ± 0.8 y, 171.8 ± 9.2 cm in height, 79.8 ± 28.1 kg in weight) participated in the following five experimental conditions: no mask, KF80, KF94, KF99, and N95. Inhalation resistance was ranked as KF80 < KF94 < N95 < KF99 and dead space inside a mask was ranked as KF80 = KF94 < N95 < KF99. The surface area covered by a mask was on average 1.1% of the total body surface area. The results showed no significant differences in body core temperature, oxygen consumption (VO2), carbon dioxide production (VCO2), heart rate or subjective perception among the five experimental conditions; however, cheek temperature, respiratory ventilation and blood pressure were greater for KF80 or KF94 conditions when compared to KF99 or N95 conditions (p<0.05). The differences among mask conditions are attributed to the dead space or specific designs (cup type vs pleats type) rather than the filtration level. In addition, the results suggest that improving mask design can help mitigate respiratory resistance from increased filtration.