• Journal of Korean Society of Water and Wastewater
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• v.25 no.1
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• pp.41-49
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• 2011

The diffuser which is conventionally adapted to MBR, has problem that decreasing the cleaning effect of membrane module by inflexible air supply due to the occlusion of sludge from diffuser hole. To solve this problem, diffuser structure of submerged module should be improved to discharge sludge which is flow into the diffuser for prevent occlusion in the diffuser. In this study, the structure of the diffuser was reformed to open lower part for preclusion the blocking. And the outlet diameter of the diffuser was drawn through the condition for the depth of water and air rate, to prevent air-leak condition of improved diffuser. Moreover, application is evaluated by comparing test with occlusion effect of the conventional and improved diffuser. From the results, air-water boundary changes are steady with changes of water depth and it shows linear relation about air rate. By using this linear numerical formula, the height of diffuser's outlet can be decided. Also, it displays that it can prevent the occlusion effect during the comparing test. Hereafter, if this diffuser is applied to practical MBR process, the occlusion problem of diffuser will be disappeared.

• Journal of the Korean Institute of Gas
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• v.25 no.1
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• pp.7-13
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• 2021

The re-liquefaction drum is a product that installed spray nozzles at the top to directly spray overcooled LNG into evaporative gas and installed demistors to facilitate gas separation, which was developed to increase the re-liquidity efficiency of small scale re-liquefaction facilities. In the hydrostatic test of the drum, no leakage occurred even at a pressure of 1.5 times the design pressure, but during the BOR(Boil Off Rate) test, the bolt loosening occurred due to contraction and expansion by temperature change. For the continued use of the product, insulation construction on flange connections was developed to enable detachment and attachment, and the comparison of heat load with existing insulation confirmed that it was very small compared to the inlet flow rate in the drum.

• Journal of Hydrogen and New Energy
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• v.34 no.3
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• pp.297-306
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• 2023

The frequency of fatal accidents that can occur at hydrogen refueling station was compared with the risk criterion for the general public suggested by the health and safety executive. If hydrogen refueling station meets the accident prevention facility standards presented in KGS Code FP216/217, it was confirmed that the risk of hydrogen refueling station was not at an unacceptable (intolerable) risk level. However, the risk of hydrogen refueling station due to small leak was analyzed as low as reasonably practicable. Therefore, methods for improving the safety instrumented function of hydrogen refueling station were reviewed. It was confirmed that the risk of hydrogen refueling station can be affected by the number of installed safety instrumentation system components, redundant architecture, mission time, proof test interval, etc. And methods for maintaining the risk of hydrogen refueling station at an acceptable risk level have been proposed.

• Phonetics and Speech Sciences
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• v.7 no.4
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• pp.93-99
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• 2015

In case of PAS test, the air is sometimes leaked although the mask is tightly attached to the face, which is not reliable on the measured values. Therefore, this study aimed to assist the clinical practice suggesting the test method of PAS without air leakage. In the healthy subjects with 12 males and 12 females over 19 years old, three types of tests were performed on the voicing efficiency among the protocol of PAS Model 6600. They are; first, to attach the mask tightly to the face holding the handle of PAS with the subject's two hands (Method 1); second, to attach the mask tightly to the face holding the handle of PAS with the subject's one hand and pushing the body of PAS strongly with the other hand (Method 2); and third, to attach the mask tightly to the face pushing the upper part of the mask by the tester when the subject attached the mask to his or her face holding the handle of PAS with two hands (Method 3). Upon the study analyses, the mean negative pressure, the mean phonogram, subglottic air pressure, and voicing efficiency were shown to be statistically significantly different during PAS test in males depending on the methods. (p<.05) In case of females, only the target airflow rate showed significant difference depending on the methods during PAS test. (p<.001) In conclusion, Method 2 enhanced the noise level and strength while Method 1 was likely to leak the air more compared to the other two methods in males. In case of females, Method 1 showed significant leakage of the air flow. Not to allow the air flow leakage without affecting the outcome of PAS test, it will be the most useful for the tester to push the mask to the subject's face tightly (Method 3).

• Investigative and Clinical Urology
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• v.59 no.6
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• pp.410-415
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• 2018

Purpose: Despite meticulous techniques, surgical complications continue to be problematic in kidney transplant recipients. Role of routine stenting to reduce complications is controversial. In this study, we compare incidence of early urological complications, lymphoceles, urinary tract infections (UTI) and graft function; with or without double-J stenting. Materials and Methods: All patients who underwent live related donor renal transplantation from February 2014 to February 2016 were included. Transplants prior to February 2015 were without routine stenting; subsequent transplants were with routine stenting. Patients with neurogenic bladder, previously operated bladder and delayed or low urinary output were excluded. Followup was for at least three months. Descriptive statistics was performed for all parameters. Chi square test and Fisher's Exact test were used for qualitative variables. For quantitative variables, Mann-Whitney test was used to test median difference and independent samples t-test for mean difference. The p-value ${\leq}0.05$ was considered significant. Results: We analysed 74 patients (34 stented and 40 non-stented). There was no difference in the incidence of urinary leak, anastomotic obstruction, lymphoceles or UTI (p>0.4 for all comparisons). However, mean estimated glomerular filtration rate at sixth day, 14th day, one month and two months were 76.1 vs. 61.5 (p=0.025), 72.1 vs. 56.6 (p=0.005), 79.4 vs. 63.1 (p=0.002) and 82.0 vs. 63.3 (p=0.001) in the stented versus non-stented groups. Conclusions: Placement of ureteral stent in renal transplant does not significantly affect the incidence of early urinary complications or UTI. However, graft function is significantly better in stented recipients, at least in the short term.

• Journal of the Korean Institute of Gas
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• v.13 no.5
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• pp.1-6
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• 2009

This paper presents the fuel consumption effects of LPG vehicle depending on the atmospheric temperature, LP gas leakage of vaporizer, viscosity of engine oil and engine load conditions. The fuel consumption test results show that when the temperature of engine temperature rises, the fuel consumption efficiency increases in general. The fuel consumption efficiency for an atmosphere temperature of $24.2^{\circ}C$ is 13.6% high compared to that of $1^{\circ}C$. No leak vaporizer on fuel consumption efficiency is 5.3% high compared to that of the LP gas leak vaporizer. The fuel economy of new engine oils is just 1.1% high compared to that of used oils with a LPG vehicle mileage of 9,500km. This is not an influential factor compared with an atmospheric temperature and a LP gas leakage. The more important factors on the fuel consumption efficiency are driving conditions such as a rapid braking, abrupt start and fast acceleration. The test results indicate that the normal start is 32.3% high compared to that of an abrupt start and the fast acceleration is 10.8% high compared with that of an abrupt start. And the fuel consumption efficiency for a rapid braking is 18.3% higher than that of an abrupt start. These indicate that the driving condition is very important to reduce the fuel consumption rate.

• Journal of Korean Academy of Nursing Administration
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• v.3 no.1
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• pp.93-106
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• 1997

By the increase of the rate of existence of the hemodialyzing patients, they were required the long run treatment. Regardless of medical insurance expansion, hemodialyzing cost much expenses so that hospital has been considering the reuse of hemodialyzer and flowing euqipments along with the diverse study and progress of the ways of hemodialyzing and medical instruments. This study was aimed to provide the basic materials regarding the reuse of hemodialyzer which is used for the patients of chronic renal disease. The reusing program in the artificial kidney center of K hospital has been used for this study from 50 patients aften one year result from Sep. 1995 through Aug. 1996. Automatic equipment of DRS-4 made by Seratronic Co., was used as the equipment and it was retreated with the function test simultaneously. Compliaction and confirmation of the infection were by the records of the hemodialysis of the patients. SPSS was used for the analysis of the materials by computerization. The character of the patients and the rate of removal was by mistake and percentage, function test and rate of complication by Ftest(ANOVA) and the rate of complication per items by ${\chi}^2$ and Ftest. As the post test the Duncan's test was used for the statistically significant different variables in the standard of p<.05 after Ftest. The followings are the summary of the result : 1) In the function test of the new hemodialyzer and the reused one, and in all of CA110 and CF15.11, the dialyzer ultrafiltration coeffient(KUf) was appeared to have been higher in the reusing groups than the first use ones. This has been the normal limit showing no troubles with them. 2) In the function test of the new and reused hemodialyzer, in all of CA110 and CF15.11, the total blood volume was appeared to have been the less value in the reuse groups than the new ones. This was the price within 80% of the first price that both showed possible for use. 3) The result of reuse hemodialyzer of CA110 was $29.48{\pm}7.83$ in average in the test of leak test while $17.3{\pm}7.96$ in reuse of CF15.11. The normal limit of <60 was the leak test result. So both of the hemodialyzer was normal for reuse. 4) The rate of removal of Blood Urea Nitrogen(BUN) was 72.25% in CA110 hemodialyzer by reusing 16-20 times as the highest rate showing the better result in the reuse hemodialyzer, while in CF15.11 hemodialyzer showed 71.16% by highest rate in the first use by the highest rate with no difference from the reuse. 5) The rate of removal of serum creatinine of CA110 was 64.08% by highest rate in reuse of 1-5 times by showing better result in reuse hemodialyzer. While in CF15.11 66.47% the highest by reuse of 16-20 times showing no difference from each other. 6) No patients were admitted or precribed by antibiotics in relation with reuse dialyzer and no reports were shown about hepatitis $B{\cdot}C$. AIDS in fection. 7) Of the total 248 episods of complication due to the hemodialyzing, 86 by first use, 73 by 1-5 times, 35 by 6-10 times, 35 by 11-15 times and 19 by 16-20 times have been shown which have had no significant difference between the groups. 8) In the comparison of the expense for the hemodialyzer, there was the effect of saving 11,597.6 Won between the first and reuse hemodialyzer. And by decreasing the extracted materials, they did the great role of disposing the waste matters.

• Tuberculosis and Respiratory Diseases
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• v.43 no.3
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• pp.308-322
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• 1996

Background : Neutrophils are considered to play critical roles in the development of acute respiratory distress syndrome. Histamine, which is distributed abundantly in lung tissue, increases the rolling of neutrophills via increase of P-selectin expression on the surface of endothelial cells and is known to have some interrelationships with IL-1, IL-8 and TNF-$\alpha$. We studied to investigate the effect of the histamine on the acute lung injury of the rats induced by intratracheal insufflation of TNF-$\alpha$ which has less potency to cause lung injury compared to IL-1 in rats. Methods : We intratracheally instilled saline or TNF(R&D, 500ng), IL-1(R&D, 50ng)or histamine of varius dose(1.1, 11 and $55\;{\mu}g/kg$) with and without TNF separately in Sprague-Dawley rats weighing 270-370 grams. We also intratracheally treated IL-1(50ng) along with histamine($55\;{\mu}g/kg$). In cases, there were synergistic effects induced by histamine on the parameters of TNF-induced acute lung injury, antihistamines(Sigma, mepyramine as a $H_1$ receptor blockade and ranitidine as a $H_2$ receptor blockade, 10 mg/kg in each)were co-administered intravenously to the rats treated TNF along with histamine($1.1\;{\mu}g/kg$) intratraeheally. Then after 5 h we measured lung lavage neutrophil numbers, lavage cytokine-induced neutrophil chemoattractants(CINC), lung myeloperoxidase activity(MPO) and lung leak. We also intratracheally insufflated TNF with/without histamine($11\;{\mu}g/kg$), then after 24 h measured lung leak in rats. Statistical analyses were done by Kruskal-Wallis nonparametric ANOVA test with Dunn's multiple comparison test or by Mann-Whitney U test. Results : We found that rats given TNF, histamine alone(11 and $55\;{\mu}g/kg$), and TNF with histamine(l.1, 11, and $55\;{\mu}g/kg$) intratracheally had increased (p<0.05) lung MPO activity compared with saline-treated control rats. TNF with histamine $11\;{\mu}g/kg$ had increased MPO activity (P=0.0251) compared with TNF-treated rats. TNF and TNF with histamine(1.1, 11, and $55\;{\mu}g/kg$) intratracheally had all increased (p<0.05) lung leak, lavage neutophil numbers and lavage CINC activities compared with saline. TNF with histamine $1.1\;{\mu}g/kg$ had increased (p=0.0367) lavage neutrophil numbers compared with TNF treated rats. But there were no additive effect of histamine with TNF compared with TNF alone in acute lung leak on 5 h and 24 h in rats. Treatment of rats with the $H_1$ and $H_2$ antagonists resulted in inhibitions of lavage neutrophil accumulations and lavage CINC activity elevations elicited by co-treated histamine in TNF-induced acute lung injury intratracheally in rats. We also found that rats given IL-1 along with histamine intratracheally did not have increase in lung leak compared with IL-1 treated rats. Conclusion : Histamine administered intratracheally did not have synergistic effects on TNF-induced acute lung leak inspite of additive effects on increase in MPO activity and lavage neutrophil numbers in rats. These observations suggest that instilling histamine intratracheally would not play synergistic roles in neutrophil-mediated acute lung injury in rats.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.10 no.2
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• pp.105-115
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• 2012

Necessity of demonstration test to evaluate the structural integrity of a basket for accident conditions arose during license approval procedure for the WSPP's dry storage facility named MACSTOR/KN-400. A drop test facility for demonstration was constructed in KAERI site and demonstration tests for basket drop were conducted. As the upper welding region of a loaded basket was collided with a dropped basket during the drop test, the welding in this region was fractured and leakage happened after the drop test. The enhancement of basket design was needed since the existing basket design was not able to satisfy the performance requirement. The directions for design modification were determined and six enhanced designs were derived based on these directions. Structural analyses and specimen tests for each enhanced design were conducted. By evaluating structural analysis results and test results, one among six enhanced designs was decided as a final design for revision. The final design was the one to reduce the height of central post of a basket and to decrease the impact velocity with a dropped basket. Test basket models were fabricated with accordance with the final enhanced design. Additional demonstration test was performed for this test model and all the performance requirements were satisfied.

• Journal of the Korean Wood Science and Technology
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• v.40 no.5
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• pp.319-326
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• 2012

Han-green building is one of the modernized Korean traditional buildings developed by Korea Forest Research Institute. This building was developed to increase the competitiveness of Korean traditional building using state-of-art technologies; hence Han-green building has the inherent characteristics of traditional building such as exposed wood frame in wall. Because of discontinuity in wall by the exposed wood frame, there is a concern on heat-air leaking in terms of energy performance. In this study, air-tightness of Han-green building was evaluated to investigate the influence of gaps between frames and in-fill walls. Blower door test was carried out to evaluate the air-tightness, and air-change rate (ACH50) was evaluated by averaging four set of pressurization and depressurization test. The air-change rate of Han-green house was 5.91 $h^{-1}$. To improve energy performance of Han-green house, thermal infrared images of Han-green house were taken in winter with heating to find out where the heat loss occurred. It was found that the building lost more heat through gaps between frames and in-fill walls rather than through other parts of this building. After covering all the gaps by taping, the blower door test was performed again, and the air-change rate was improved to 5.25 $h^{-1}$. From this analysis, it was concluded that the heated air can leak through the gaps between frames and walls. Therefore, when one designs the post and beam building with exposed frame, the detail design between frame and wall needs to be carefully dealt. However, Han-green building showed relatively high air-tightness comparing with other country research results.