• Journal of the Korean Society of Marine Environment & Safety
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• v.30 no.2
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• pp.165-175
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• 2024

Hydrogen is being touted as one of the energy sources to combat the climate change crisis. However, hydrogen can leak into enclosed spaces, rise to the ceiling, accumulate, and cause fires and explosions if it encounters an ignition source. In particular, ships that transport hydrogen or use it as a fuel comprise multiple enclosed spaces. Therefore, the dif usion characteristics within these spaces must be understood to ensure the safe use of hydrogen. The purpose of this study is to experimentally determine the diffusion characteristics of helium, which has similar properties to hydrogen, in a closed space on board a ship, and to determine the change in the oxygen concentration along the leakage direction as the air change per hour(ACH) increases to 25, 30, 35, 40, and 45 through CFD simulation. The study, results revealed that the oxygen concentration reduction rate was 2% for leakage in the -z direction and 1% for leakage in the +x and +z directions, and the ventilation time was 15 min 30 s for leakage in the -z direction, 7 min for leakage in the +x direction, and 9 min for leakage in the +z direction, showing that differences existed in the oxygen concentration and ventilation time depending on the leakage direction. In addition, no significant difference was observed in the rate of oxygen concentration reduction and ventilation time in all leakage directions from the ACH of 35 and above in the experimental space. Therefore, because the oxygen concentration and ventilation time were not improved by increasing the ACH, 35 was noted as the optimal ACH in this experimental environment.

• Annals of Hepato-Biliary-Pancreatic Surgery
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• v.26 no.1
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• pp.84-90
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• 2022

Backgrounds/Aims: Postoperative pancreatic fistula (POPF) after pancreaticoduodenectomy (PD) remains a dreadful complication. Duct-to-mucosa pancreaticojejunostomy (DTMPJ) is a commonly performed anastomosis after PD. This study aims to evaluate whether there is a size limit of pancreatic duct below which POPF rate increases significantly after DTMPJ. Methods: A retrospective study was performed from a database with prospectively collected data on consecutive patients undergoing DTMPJ. Results: Between the years 2003 and 2019, a total of 288 patients with DTMPJ were recruited. POPF occurred in 56.3% of the patients, of which 43.8% were biochemical leak, 8.7% were grade B, and 1.4% were grade C. Overall operative morbidity was 51.4%, of which 19.1% were major complications. Five patients (1.7%) died within 90 days of operation. Patients with grade B/C POPF had significantly soft pancreas (p < 0.001), smaller duct size (p = 0.031), and a diagnosis of carcinoma of the pancreas (p = 0.027). When a clinically significant POPF rate was analysed based on the pancreatic duct diameter, pancreatic duct size ≤ 1 mm had the highest POPF rate (35.7%). There was a significant difference in POPF rate between adjacent ductal diameter ≤ 1 mm and > 1 mm to 2 mm (35.7% vs 13.3%; p = 0.040). Multivariable analysis showed that for the soft pancreas, pancreatic duct diameter ≤ 1 mm was the only significant predictive factor for POPF (p = 0.027). Conclusions: DTMPJ can be safely performed for pancreatic duct > 1 mm without significantly increased POPF risk.

• Journal of Navigation and Port Research
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• v.48 no.4
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• pp.274-283
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• 2024

Climate change is currently one of the most pressing environmental issues, primarily caused by carbon emissions from fossil fuel usage. As a result, alternative fuels that effectively reduce carbon emissions are garnering more attention. Among these alternatives, hydrogen has numerous advantages, such as its ability for large-scale storage and transport. However, it is crucial to prioritize safety measures, particularly in facilities that handle hydrogen, due to its highly flammable and fast-spreading nature. This study aims to compare and analyze the placement of supply and exhaust vents to efficiently release hydrogen in the event of a leak in an enclosed space. The experiments involved six different scenarios, each with various combinations of supply and exhaust vents. To ensure the experimental process's safety, helium, which shares similar physical properties with hydrogen, was used to analyze the internal oxygen concentration during ventilation system operations. The results revealed that among the six scenarios, Case 2, which employed a lower side supply vent and an upper side exhaust vent, exhibited the shortest ventilation time of 4 minutes and 30 seconds. Additionally, the decrease rate in oxygen concentration was examined in the upper, middle, and lower areas. Ventilation utilizing an upper surface supply vent and two exhaust vents on the upper surface and upper side (Case 6), showed lower oxygen concentration values in the upper area, while Case 2 yielded lower values in the middle and lower areas. Therefore, it is crucial to select an appropriate supply and exhaust vent configuration considering the space's characteristics and usage environment.

• Korean Journal of Poultry Science
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• v.29 no.4
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• pp.237-241
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• 2002

To observe the effect of Induced molting on the recovery patterns of abdominal fat, visceral organs, and muscle tissues in spent laying hens after induced molting, three hundred sixty 77-wk-old, Babcock White hens were divided into 36 experimental units of 10 hens each and subjected to molt induction for seven wk. The post-molt production phase was spread over 84 to 126 wks of age. Thirty-six birds were randomly slaughtered and dressed at the pre-molt, 5% egg production, Peak, and end Phases of e99 Production. The body weight, abdominal fat, relative weight and length of visceral organs were measured. Proximate compositions of breast and thigh muscles were analyzed at each stage. The body weight was found to be minimal at the 5% egg Production stage, but increased as the egg Production increased for the rest of production. The pattern of abdominal fat change was very similar to that of body weight. The relative weight of the liver decreased to the lowest at the start of Post molting stage, but Peaked at the end Phase of egg Production (P<0.05). However, he heart and gizzard were observed to reach their maximum weight at the 5% egg Production (P<0.05), whereas they were, similar to those of the pre-molt phase for the rest of the production stages. Both intestine and reproductive tracts were found o be significantly smaller at 5% egg Production than at the other stages; however, their sizes increased gradually, reaching leak at the end Phase of e99 Production (P<0.05). Fat contents in breast and thigh muscles decreased significantly to the lowest at the start of the Post-molt stage, but increased to the highest at the end Phase of e99 Production (P<0.05). Thus, he Present study indicated that the molting process reduced body weight by decreasing the weights of abdominal fat and other visceral organs. Molting also influenced the breast and thigh muscle composition by decreasing fat content.

• Journal of the Korean Society for Marine Environment & Energy
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• v.12 no.4
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• pp.307-319
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• 2009

Carbon dioxide capture and storage (CCS) technology has been regarded as one of the most possible and practical option to reduce the emission of carbon dioxide ($CO_2$) and consequently to mitigate the climate change. Korean government also have started a 10-year R&D project on $CO_2$ storage in sea-bed geological structure including gas field and deep saline aquifer since 2005. Various relevant researches are carried out to cover the initial survey of suitable geological structure storage site, monitoring of the stored $CO_2$ behavior, basic design of $CO_2$ transport and storage process and the risk assessment and management related to $CO_2$ leakage from engineered and geological processes. Leakage of $CO_2$ to the marine environment can change the chemistry of seawater including the pH and carbonate composition and also influence adversely on the diverse living organisms in ecosystems. Recently, IMO (International Maritime Organization) have developed the risk assessment and management framework for the $CO_2$ sequestration in sub-seabed geological structures (CS-SSGS) and considered the sequestration as a waste management option to mitigate greenhouse gas emissions. This framework for CS-SSGS aims to provide generic guidance to the Contracting Parties to the London Convention and Protocol, in order to characterize the risks to the marine environment from CS-SSGS on a site-specific basis and also to collect the necessary information to develop a management strategy to address uncertainties and any residual risks. The environmental risk assessment (ERA) plan for $CO_2$ storage work should include site selection and characterization, exposure assessment with probable leak scenario, risk assessment from direct and in-direct impact to the living organisms and risk management strategy. Domestic trial of the $CO_2$ capture and sequestration in to the marine geologic formation also should be accomplished through risk management with specified ERA approaches based on the IMO framework. The risk assessment procedure for $CO_2$ marine storage should contain the following components; 1) prediction of leakage probabilities with the reliable leakage scenarios from both engineered and geological part, 2) understanding on physio-chemical fate of $CO_2$ in marine environment especially for the candidate sites, 3) exposure assessment methods for various receptors in marine environments, 4) database production on the toxic effect of $CO_2$ to the ecologically and economically important species, and finally 5) development of surveillance procedures on the environmental changes with adequate monitoring techniques.

• Journal of Korean Medical classics
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• v.5
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• pp.200-251
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• 1992

As concerned the life and the medical idea of Choo, Tan-Kye(朱丹溪), which it can be summarized as follows by studying. 1. Tan-Kye(丹溪) lived in the end of the won dynasty(元代末期), When the people starved and suffered from a flood-disaster and drought. etc, also the social conditions were in disorder on account of the corrupt ion of politics. And Cheol Kang seong(浙江省), located in the south region of China, has sterile soil and the climate condition humid and heatful. So the south district peoples have very weak constitution. So We can found that his medical idea reflected the phases of the periods and the regional enviornmental situations. 2. For that reason, Tan-Kye(丹溪) rejected the prescription of the "WHa Che Gook Bang(和劑局方)" which was prevalent at that time, in which the the pungent-dried herbs were widly used ; So he persisted in the "Sang Wha Lon(相火論)" and the "Positivity is usually excedeed while the negativity deficient(陽有餘陰不足論)". Then he treated with the drugs to nourish the negativity for the prime object to be applied in the clinic. 3. Tan-Kye(丹溪) refined the follows from the natural law; Heaven is to the positivity(陽) and the Earth is defined the negativity(陰), so the heaven is to the Macro(大) and the earth, micro(小):So the Sun is to the Positivity(陽), the Moon, the Negativity(陰): as to the Sun is always full while the moon always defected too. Therefore the "positivity is always excedeed for that the negativity is deficientalways(陽有餘陰不足)". In Human body, "the negativity energy (陰精) "is hard formed-easily defected(難成易虧)". And the heat(相火) in the body can be moved easily and let the negative energy to leak out. Therefore the more the positivity excedeed, the more the negativity deficient"(陽當有餘陰常不足). 4. He made it expanded the contents of the "Heat(相火)" in the Chapter Woon Chi of the Nae Kyeong(內徑) and discribed, the Life-string of the human body is originated from the movement of the "Heat with unique energy(相火一氣)". And more in human body, it is specifically regulated by the two visceras, Liver and Kidney, and is distributed in the 'Pericardium(心包絡)' 'Tripie Warmer(三焦)' 'Gallbladder(膽)' etc. In the point of his assertion of heat(相火), it is concluded both the physiological and the pathological heat of all. 5. Tan-Kye(丹溪) grew up in the family or the Confucianism. He was instructed the Confucianism(性理學) from Heo-Kyeom(許謙), the fourth diciple of Chu-Ja(朱子), and was received the Yoo Chang Ri(劉 張 李)'s triple doctrine from the La Tae Moo(羅太無), the second disciple of Yoo Wan So(劉完素). So there are much of content of Confucianism(性理學) in his medical thedry, and his theory has succeeded the achievements of the triple study. 6. About the theory of the "positivity is usually excedeed while the negativity deficient"(陽常有餘陰常不足論) of Tan-Kye, it was asserted that the positivity is never sufficient for the vital mainspring, by Chang, Kye-Pin(張介賓) and Lee, Kyoo-Zoon(李奎晙) etc. And for the Heat theory(相火論), eventhough the scholars of postorior generations criicized all of that, there are defect of the content and unification between them. 7. The father of the "Cha Eum Pa(滋陰派), Tan-Kye(丹溪) contributed considerably to the development of the oriental medicine and to the general therapy for the various diseases(一般雜病施治). 8. there are handed down and remained twenty or more of volumes of list of his writings. Among them, except "Kyeok Chi Yeo Ron"(格致餘論), "Kuk Pang Pal Hyeu"(局方發揮), they are reorganized by posteriority. There are Cho, Do-Chin(趙道震). Cho, Ee-Teok(趙以德), Tae, Sa-Gong(戴思恭), Wang Ri(王履) and Yoo, Suk-Yeon(劉淑淵) etc as disciples of his. And Wang Ryoon(王論) and Woo Pak(虞搏) as the admirer of him.

• Journal of the Korean Geosynthetics Society
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• v.12 no.4
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• pp.67-76
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• 2013

Landfill require special care due to the dangers of nearby surface water and underground water pollution caused by leakage of leachate. The leachate does not leak due to the installation of the geomembrane but sharp wastes or landfill equipment can damage the geomembrane and therefore a means of protecting the geomembrane is required. In Korea, in accordance with the waste control act being modified in 1999, protecting the geosynthetics liner on top of the slope of landfill and installing a drainage layer to fluently drain leachate became mandatory, and technologies are being researched to both protect the geomembrane and quickly drain leachate simultaneously. Therefore, this research has its purpose in studying the drainage functions of leachate and protection functions of the geomembrane in order to examine the application possibilities of Geo-Multicell-Composite (GMC) as a Leachate Collection Removal and Protection System (LCRPs) at the slope on top of the geomembrane of landfill by observing methods of inserting filler with high-quality water permeability at the drainage net. GMC's horizontal permeability coefficient is $8.0{\times}10^{-4}m^2/s$ to legal standards satisfeid. Also crash gravel used as filler respected by vertical permeability is 5.0 cm/s, embroidering puncture strength 140.2 kgf. A result of storm drain using artificial rain in GMC model facility, maxinum flow rate of 1,120 L/hr even spray without surface runoff was about 92~97% penetration. Further study, instead of crash gravel used as a filler, such as using recycled aggregate utilization increases and the resulting construction cost is expected to savings.

• Fire Science and Engineering
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• v.34 no.2
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• pp.156-165
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• 2020

In this paper, the application of evacuation delay time (Cognition time + initiation time) and examine the degree of opening of fire doors in households for evaluating evacuation safety and suggest a realistic alternative. In order to proceed with this study, first of all, the preliminary investigation on evacuation safety evacuation of residential-type buildings (Apartment, urban living houses, etc.) among the performance-oriented design targets of Gwangju Metropolitan City, which was implemented until June 2018. Then, for the two representative types that are commonly used among the previously surveyed buildings, evacuation delay time is applied to W1, W2, and respectively simulating the opening of the doors is applied to th full open, 1/4 open, the leakage gap and evacuation safety evaluation was performed. As a result of evaluating evacuation safety was found that it is difficult to secure evacuation safety regardless of evacuation delay time W1 and W2 when the fire door is fully open and 1/4 open, Only when the leakage gap is applied evacuation safety was ensured even if evacuation delay time W2 was applied. Therefore, when a residential building is subject to performance-oriented design, evaluating the application of W2 rather than W1 is considered for evacuation delay time to reflect concern about privacy infringement due to CCTV installation, etc. In order to secure the Smoke blocking performance of the fire door and to improve the performance-oriented design, I would like to propose to consider the method of applying a leak gap to the degree of opening of the fire door. Through this, it is expected that the performance-oriented design will be a step further by performing evacuation safety evaluation with more realistic data.

• Advances in pediatric surgery
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• v.1 no.2
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• pp.149-161
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• 1995

The first national survey on esophageal atresia and tracheoesophageal fistula was conducted to access the current status of its incidence, clinical manifestation, preoperative diagnosis and management, type of its anomaly, associated anomalies, and surgical results and course. The 43 members of the Korea Association of Pediatric Surgeons received questionnaires and registration forms to be filled out on each patient who were born during the three years from January 1, 1992 through December 31, 1994. Questionnaires composed of six broad areas which include 1) preoperative diagnosis and management, 2) surgical technic, 3) long gap, 4) postoperative management, and 5) complications and courses. A total of 148 cases was returned by 28 members working at 23 institutions and 27 members returned questionnaires. We obtained the following results by analysis of the 148 cases of tracheoesophageal anomalies. The incidence of tracheoesophageal anomaly was about 1/10,000-11,000 in 1994, which is one third of that of anorectal malformations in Korea and the distribution of the patients was almost proportionate to the size of each province. Both sexes are about equally affected. Majority of the members make diagnosis of tracheoesophageal anomaly by taking a simple infantogram with a radiopaque tube in upper pouch and a little under half(46%) prefers to perform echocardiography as a part of preoperative management to identify congenital heart disease and lateralize the aorta. Esophageal atresia with distal TEF(87.5%) was by far the most common and there were pure esophageal atresia(5.6%), H-type TEF(2.1%), and so on. About half(49%) of the patients had one or more associated anomalies in addition to tracheoesophageal anomalies. Congenital heart disease was associated in 46 cases(31%), anorectral malfomations in 19 cases(13%), musculoskeletal anomalies in 15 cases(10%), genitourinary anomalies in 10 cases(7%) and gastrointestinal anomalies in 7 cases(5%). Postoperatively, parenteral nutrition and assisted ventilation were given in 66% and 52% of patients respectively. Ninety three(74%) of 126 cases who underwent sugical procedure, experienced one or more complications such as respiratory complication(65%), leak(22%), stricture(21%) and so on. The survival rates related to the Waterston risk categories were 90.2% in group A, 71.4-75% in $B_1$, $B_2$, and $C_1$, groups, and 28% in group $C_2$, and the overall survival rate was 71.4%. Thirty six(28.6%) of 126 cases died of pneumonia/sepsis(12 cases), respiratory failure(12 cases), and congenital heart disease(4 cases). With short term follow-up, 69% of patients have been excellent whereas remainders of the cases have suffered from some sort of morbidity related to gastroesophageal reflux, recurrent respiratory infection, and esophageal stricture.

• Tuberculosis and Respiratory Diseases
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• v.44 no.5
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• pp.975-991
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• 1997

Background : Many patients with isoniazid and rifampin-resistant pulmonary tuberculosis have organisms that are also resistant to other first-line drugs. Despite of aggressive retreatment chemotherapy, the results are often unsuccessful, with a failure rate approaching 40%. Recently, there has been a revival of resectional surgery for the treatment of multidrug-resistant pulmonary tuberculosis. Methods : A retrospective analyses of the case records and radiographic findings were done. Between January 1991 and December 1995, 14 human immunodeficiency virus (HIV)-seronegative patients with multidrug-resistant pulmonary tuberculosis were selected for resection to supplement chemotherapy. All patients had organisms resistant to many of the first-line drugs, including both isoniazid and rifampin. Results : Despite of aggressive therapy for median duration of 9.5 months, 12 of the 14 patients (86%) were still sputum smear and/or culture positive at the time of surgery. The disease was generally extensive. Although main lesions of the disease including thick-walled cavities were localized in one lung, lesser amounts of contralateral disease were demonstrated in 10 of 14 (71%). Types of surgery performed were pneumonectomy including extrapleural pneumonectomy in six patients, lobectomy or lobectomy plus in six patients, and segmentectomy in two patients. The resected lung appeared to have poor function ; preoperative perfusion lung scan showed only 4.8% of the total perfusion to the resected portion of the lung. There were no operative deaths. Two patients had major postoperative complications including empyema with bronchopleural fistula and prolonged air leak, respectively. Of the 14 patients, 13 (93%) remained sputum-culture-negative for M. tuberculosis for a median duration of 23 months and one remained continuously sputum smear and culture positive for M. tuberculosis. Conclusion : On the basis of comparison with historical controls, adjunctive resectional surgery appears to play a significant beneficial role in the management of patients with multidrug-resistant pulmonary tuberculosis if the disease is localized and there are adequate reserve in pulmonary function.