• Journal of the Korean Institute of Gas
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• v.28 no.1
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• pp.19-26
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• 2024

In workplaces handling flammable gas such as hydrogen, hazardous area is determined through KS C IEC 60079-10-1 standard. Because this standard determines the hazardous distance based on the release characteristic regardless of the type of gas, indoor/outdoor conditions, and atmospheric conditions, concerns are being raised about the effectiveness. In this study, simulations (PHAST, HyRAM) were performed to calculate the hazardous distance for hydrogen under various release characteristics and atmospheric conditions, and compared these results to IEC standard log-log graph. Also, we performed regression analysis according to each result. we found that the simulation results were 0.6 to 3.8 times less than the IEC standard, presented convenient linear regression equations. In addition, We confirmed that the results of hazardous distance varied based on wind velocity and atmospheric stability at the same release characteristic. In addition, we derived linear regression equations for release characteristics and hazardous distance that can be conveniently utilized. So, when classifying hazardous area in workplaces where they handle the hydrogen, the integrated graph and linear regression equation are helpful for confirming the hazardous area. Moreover, it is expected that the economic burden will be minimized by being able to classify reasonable hazardous area and to greatly reduce the risk of hydrogen explosion.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.8
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• pp.1160-1168
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• 2018

Objective: This study was conducted to compare morphological defects, viability, motility (MOT), fertility (F), and hatchability (H) in four Korean native chicken breeds (KNCBs), and to evaluate whether defective segments of spermatozoa are associated with MOT, F, and H. Methods: Four KNCBs, including Korean Ogye (KO), Hwangbong (HB), Hyunin Black (HH), and Hoengseong Yakdak (HY) were used. White Leghorn (WL) was used as a control. Nine cocks from each breed were randomly assigned into three groups. Semen was collected by abdominal massage method. Eosin-nigrosin staining method was used to identify live-dead spermatozoa. Different segments and specific morphological defects of spermatozoa were identified using 4', 6-diamidino-2-phenylidole and MitoTracker Red CMXRos. F and H rates were evaluated following artificial insemination (AI). Results: KO had the highest MOT rate compared to HY. Viable normal sperm rates of KO and HH were high and comparable with WL. HY spermatozoa had the highest viable abnormal sperm (VAS) or morphological defect rate followed by HB. Likewise, HB spermatozoa had the highest dead sperm (dead) rate compared to KO, HY, and WL. Bent, coiled, detached, broken, and knotted were common identified specific morphological defects for all breeds. Most morphological defects were at the head and tail in all breeds. VAS showed strong negative correlation with MOT (r = -0.697) and F (r = -0.609). Similarly, defective tail was negatively correlated with MOT (r = -0.587), F (r = -0.797), and H (r = -0.448). The F and H rates of KO and WL were comparable. Conclusion: These data indicate that most identified specific morphological defects are at the head and tail. VAS and defective tail were associated with poor motility, F, and H. KNCBs showed more morphological defects than WL. Finally, these results will facilitate successful AI and semen cryopreservation.

• Journal of Acupuncture Research
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• v.21 no.1
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• pp.59-69
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• 2004

Objective: The purpose of this study is to find the characteristics of MMPI in Bell's palsy patients. Methods: 40(21 male, 19 female) patients with Bell's palsy who visited Dept. of Acupuncture and Moxibustion, Bundang Oriental Medicine Hospital, Dongguk University completed a Minnesota Multiphasic Personality Inventory (MMPI)-383. The mean age was 43 years(range 18-72). MMPI scores were analyzed about validity scales, neurosis clinical scales, other clinical scales and by Two code method. Patients's MMPI scores were compared with Korean standard of MMPI. Results: The validity scales were within normal range. The neurosis clinical scales were within normal range. The other clinical scales were within normal range. The study of Two code method showed that D scale and Hy scale was higher than the other clinical scales. Bell's palsy patients's D scale and Hy scale means were higher than Korean standard of MMPI.

• Transactions of the Korean hydrogen and new energy society
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• v.28 no.2
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• pp.166-173
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• 2017

For commercialization of hydrogen refuelling station (HRS), we need to reduce the clearance distance for jet fire in the real entities in the HRS. Thus, we revisited the current regulations of clearance distance for jet fire in the law. The law in korea has been set up by replica of japan, not by our own scientific basis. Recently, sandia lab developed Hydrogen Risk Assessment Model (HyRAM) tools and we simulated a series of circumstances such as 10 to 850 bar with several leak hole sizes. In 850 bar with 10 mm diameter hole leak cases, it shows $4,981kW/m^2$ at 12 m separation from leak source and $1,774kW/m^2$ at 17 m separation from leak source. In 850 bar with 1 mm diameter leak hole, it shows $0.102kW/m^2$ at 12 m separation and $0.044kW/m^2$ at 17 m separation. Current law may be acceptable with 1 mm hole size with 850 bar.

• Transactions of the Korean hydrogen and new energy society
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• v.34 no.4
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• pp.381-387
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• 2023

The risk assessment (safety assessment) must be performed to verify the risks during operation and installation of the hydrogen system and to ensure safe design and operation. Among them, hazard and operability study (HAZOP), a qualitative risk assessment, is most often used to discover risk factors and secure safety. However, in HAZOP performance, there is a difference in the level of evaluation results depending on the level and experience of the evaluator, and there is a high possibility that subjective results will be derived. This study aims to develop a risk factor library that can list and provide information on potential risk factors in order to solve these problems when performing HAZOP, reduce risk factors that are omitted or overlooked.

• Journal of the Korean Institute of Gas
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• v.27 no.4
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• pp.70-77
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• 2023

In response to climate change, each country is proposing a goal to reduce greenhouse gases in its energy supply and demand plan, and the use of hydrogen gas is a topic that is always prioritized as an energy resource for implementation. A popular way to use this hydrogen gas is the use of hydrogen fuel cell vehicles, and expansion of hydrogen charging stations is essential for using these hydrogen fuel cell vehicles. However, there are several limitations to the expansion of hydrogen refueling stations, the most representative of which is resident acceptance. Most of the hydrogen charging stations currently built in Korea are located in the outskirts with low population density, so the inconvenience to hydrogen fuel cell vehicle users has not been resolved, and as a result, there has been no progress in the spread of hydrogen fuel cell vehicles. In this paper, we analyzed the consequences of accident damage to determine the risks of constructing a hydrogen charging station on a railroad site frequently used by citizens. The target hydrogen charging station site was a railroad depot in Busan, and there are trains, national highways, and commercial facilities around this site. Assuming the worst-case scenario, we would like to consider the safety of the hydrogen refueling station site by analyzing the area affected by the accident and its consequence.