• Journal of the Korean Solar Energy Society
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• v.31 no.4
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• pp.66-71
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• 2011

This study focused on the application of the Passive Solar Chamber System (PSCS) as proposed by a previous study. The seasonal performance and sizing method for the system were investigated for a feasibility of the PSCS in Korean climate. For seasonal performance, heat and ventilation performances of the PSCS were analyzed for the months of January and August. This study proposed a simple configuration method in which the designer can decide on the system size at the preliminary design stage by using system efficiency, overall heat transfer coefficient transmission, monthly solar radiation, highest and lowest temperatures. During weeks that require heating, the system showed to acquire a daily average heat amount of $860.28Wh/m^2$ day. For cooling periods, the system was computed to supply a daily average natural ventilation of $1,360.2m^3/day$ to the room. Moreover, proposed sizing method and the overall computation results showed a 6.04~7.24% error of assessment.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.3 no.3
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• pp.183-192
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• 2005

Natural ventilation in radioactive waste repositories is considered to be less efficient than mechanically forced ventilation for the repository working environment and hygiene & safety of the public at large, for example, controlling the exposure of airborne radioactive particulate matter. It is, however, considered to play an important role and may be fairly efficient for maintaining environmental conditions of the repository over the duration of its lifetime, for example, moisture content and radon (Rn) gas elimination in repository. This paper describes the feasibility of using natural ventilation which can be generated in the repository itself, depending on the conditions of the natural environment during the periods of repository construction and operation. Evidences from natural cave analogues, actual measurements of natural ventilation pressures in mountain traffic tunnels with vertical shafts, and calculations of airflow rates with given natural ventilation pressures indicate possible benefits from passive ventilation for the prospective Korean radioactive waste repository. Natural ventilation may provide engineers with a cost-efficient method for heat and moisture transfer, and radon (Rn) gas elimination in a radioactive waste repository. The overall thermal performance of the repository may be improved. The dry-out period may be extended, and the seepage flux likely would be decreased.

• Journal of Chest Surgery
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• v.25 no.12
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• pp.1542-1549
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• 1992

From March 1986 to August 1992, 18 patients underwent diaphragmatic plication for the diaphragmatic paralyses complicating various pediatric cardiac procedures. Age at operation ranged from 16 day to 84 months with mean age of 11.8 months. In order of decreasing incidence, the primary cardiac procedures included modified Blalock-Taussig shunt [ 5 ], Arterial switch operation [ 4 ], modified Fontan operation [ 2 ], and others [ 7 ]. The suspicious causes of phrenic nerve injury included overzealous pericardial resection [ 7 ], direct trauma during the procedure [ 6 ], dissection of fibrous adhesion around the phrenic nerve [ 3 ] and unknown etiology [ 2 ]. The involved sides of diaphragm were right in 10, left in 7 and bilateral in one. The diagnosis was suspected by the elevation of hem-idiaphragm on chest x-ray and confirmed by fluoroscopy. The interval between primary operation and plication ranged from the day of operation to 38 postoperative days [mean : 14 days]. The method of plication were "Central pleating technique" described by Schwartz in 16 and other techniques in 2. Five patients expired after plication and the cause of death were not thought to be correlated directly with the plication itself. In the remaining 13 survivors, extubation or cessation of positive ventilation could be done between the periods of the day of plication and 14th postoperative days [mean; 3.8day]. We have made the following conclusions : 1] Phrenic nerve paralyses are relatively common complication after pediatric cardiac procedures and the causes of phrenic nerve injury are mostly preventable; 2] Phrenic nerve palsy is associated with corisiderable morbidity; 3] diaphragmatic plication is safe, reliable and can be applicable in patients who are younger age and require prolonged positive pressure ventilation.ntilation.

• Journal of The Korean Society of Agricultural Engineers
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• v.62 no.5
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• pp.27-37
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• 2020

As domestic meat consumption increases, the broiler production industry has been larger and denser. The concentration of particulate matter (PM) and harmful gases generated is also increasing inside livestock house. However, the current research status of PM exposed to farm workers and the health effects are in the early stage. To understand PM concentration affecting workers in the broiler house, field monitoring was conducted according to its size distributions. Concentrations of PM₁₀, PM_2.5, and TD (Total Dust) were monitored using personal air samplers with teflon filter during working and moving periods considering the ventilation systems of 6 broiler houses. The purpose of this study is to monitor the PM concentration in the experimental broiler houses operated by forced ventilation system generally used in Korea and to evaluate the regional concentrations through airflow pattern. The PM concentrations were increased from inlet to outlet vents resulting in 1,872 of TD, 1,385 of PM₁₀, and 209 ㎍/㎥ of PM_2.5, respectively. The TD and PM₁₀ concentrations were increased when the workers and broilers were moving. Among them, the particle size that occupied the largest amount of PM was 13.75 ㎛. These results suggest that personal protection equipments are important to reduce the health effect from PM inhalation.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.2
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• pp.130-136
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• 1987

The studies were carried out to investigate the occurrence of excessive dried leaves during burley tobacco curing. Six different periods of ventilation during the entire stage of curing were applied. And also 3 different heights of rolling up polyethlene film for side ventilation of the curing house combined with 4 different spaces between garlands were applied from after yellowing. The high air temperature and low relative humidity from end of yellowing to end of browning stage were the most critical to occur excessive dried \eaves. As side ventilation was continued for the entire stage of curing, air temperature in curing house was lower and occurrence of excessive dried leaves were remarkably decreased. The air temperature was not affected on hanging spaces, but relative humidity that resulted significantly in decreasing of the excessive dried leaves was increased by narrowing of hanging spaces. As excessive dried leaves were increased, its price per kg was lower, its physical properties was worse and its total nitrogen and total suger were higher than those of normal cured leaves.

• Tuberculosis and Respiratory Diseases
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• v.83 no.4
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• pp.303-311
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• 2020

Background: If the duration of mechanical ventilation (MV) is related with the intensive care unit (ICU) readmission must be clarified. The purpose of this study was to elucidate if prolonged MV duration increases ICU readmission rate. Methods: The present observational cohort study analyzed national healthcare claims data from 2006 to 2015. Critically ill patients who received MV in the ICU were classified into five groups according to the MV duration: MV for <7 days, 7-13 days, 14-20 days, 21-27 days, and ≥28 days. The rate and risk of the ICU readmission were estimated according to the MV duration using the unadjusted and adjusted analyses. Results: We found that 12,929 patients had at least one episode of MV in the ICU. There was a significant linear relationship between the MV duration and the ICU readmission (R²=0.85, p=0.025). The total readmission rate was significantly higher as the MV duration is prolonged (MV for <7 days, 13.9%; for 7-13 days, 16.7%; for 14-20 days, 19.4%; for 21-27 days, 20.4%; for ≥28 days, 35.7%; p<0.001). The analyses adjusted by covariables and weighted with the multinomial propensity scores showed similar results. In the adjusted regression analysis with a Cox proportional hazards model, the MV duration was significantly related to the ICU readmission (hazard ratio, 1.058 [95% confidence interval, 1.047-1.069], p<0.001). Conclusion: The rate of readmission to the ICU was significantly higher in patients who received longer durations of the MV in the ICU. In the clinical setting, closer observation of patients discharged from the ICU after prolonged periods of MV is required.

• The Korean Journal of Food And Nutrition
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• v.27 no.1
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• pp.128-135
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• 2014

The purpose of this study is to analyze the gap in perceived importance-satisfaction rates of foreign Chinese students regarding the university foodservice selection attributes. All statistical analyses are conducted by the SPSS package program (ver 20.0). The results of the statistical analyses are as follows: The validity of the 22 food service selection attributes is being evaluated via the exploratory factor analysis and then five factors are extracted. The five factors are: 'Factor 1. Cleanness and service quality', 'Factor 2. Food quality and price', 'Factor 3. Physical environment', 'Factor 4. Convenience', and 'Factor 5. Service environment'. According to the results of one-way ANOVA, physical environment showed that significant differences across the periods of residence in Korea and the eating frequency at on campus foodservices. On the other hand, the food quality and price, convenience, and service environment showed that significant differences across the periods of residence in Korea. In addition, according to the Importance-Satisfaction Analysis results, 'ventilation of dining room' is the key aspect that university food service managers should reinforce. In conclusion, in order to increase the customer satisfaction rates, the food service managers should not only improve the quality of food and service but also the physical environments of the food service facility.

• Journal of Bio-Environment Control
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• v.6 no.3
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• pp.133-142
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• 1997

Most of the greenhouses employ the roll-up type ventilation control system. Torque required to roll-up and down might be theoretically expressed with the weight times radius of the ventilation roll; however, measured torques were two times of the theoretically estimated values. As the window film of roll-up vent is used over the periods of time, the warping and crumpling of the material caused the increase of the torque in addition to a span deformation. Therefore, this study was performed to develop an empirical torque formulae to present basic torque data and to assist the development of roll-up type ventilation control system. The empirically adjusted rolling radius (r＋a) exponentially increased at the maximum span deformation. The coefficient of rolling resistance (Cr) was about 0.7―0.8 depending upon the wrinkle status of film material.

• Journal of Chest Surgery
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• v.18 no.2
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• pp.345-351
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• 1985

Tracheal stenosis is due to tracheostomy or prolonged intubation. Development of tracheal stenosis following tracheostomy is very serious complication. In recent practice, tracheostomy has became more popular because of increased occasions of major and minor traumas. At the Dept. of thoracic surgery, Chonbuk national university hospital, we have experienced one case of tracheal stenosis following tracheostomy for assisted ventilation. Chest X-ray revealed the narrowing of trachea at cervicothoracic junction due to previous tracheostomy. We resected the narrow segment & tracheal reconstruction was performed with an excellent result in postoperative periods. Postoperative air tracheogram did not reveal demonstrable narrowing of air filled trachea.

• Journal of Chest Surgery
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• v.15 no.1
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• pp.73-76
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• 1982

For the treatment of acute respiratory failure and emergency care of an urgent patient, tracheostomy in itself may have been a life saving procedure. But, among the variable complications following tracheostomy, the tracheal stenosis gives serious clinical manifestation which can only be corrected by surgical intervention in many occasions. At the Dept. of thoracic surgery, CAFGH, we have experienced one case of tracheal stenosis following tracheostomy for assisted ventilation. Tracheogram showed a 2.5 cm segmental narrowing 5 cm below the tracheostoma. Before recon-struction, we tried to dilate the stenotic segment for about 2 months, but the result was not satisfactory to relieve dyspnea. So, we resected the narrowed segment and tracheal reconstruction was performed with an excellent result in postoperative periods till now.