• Journal of the Korean Society for Nondestructive Testing
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• v.28 no.2
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• pp.191-198
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• 2008

Flow accelerated corrosion (FAC) phenomenon of low alloy carbon steels in nuclear power plant has been known as one of major degradation mechanisms. It has a potential to cause nuclear pipe rupture accident which may directly impact on the plant reliability and safety. Recently, the equipotential switching direct current potential drop (ES-DCPD) method has been developed, by the present authors, as a method to monitor wall loss in a piping. This method can rapidly monitor the thinning of piping, utilizing either the wide range monitoring (WiRM) or the narrow range monitoring (NaRM) technique. WiRM is a method to monitor wide range of straight piping, whereas NaRM focuses significantly on a narrow range such as an elbow. WiRM and NaRM can improve the reliability of the current FAC screening method that is based on computer modeling on fluid flow conditions. In this paper, the measurements by ES-DCPD are performed with signal sensitivity analyses in the laboratory environment for extended period and showed the viability of ES-DCPD for real plant applications.

• Korean Journal of Veterinary Research
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• v.41 no.1
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• pp.99-104
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• 2001

To determine if micronucleus (MN) assay could be used to predict the absorbed dose of victims after accidental radiation exposure, we carried out to assess the absorbed dose depending on the numerical changes of MN in human peripheral blood lymphocytes after $^{60}Co\;{\gamma}-rays$ exposure in the range of 0.25 to 1 Gy, respectively. The MNs were observed at very low doses, and the numerical changes according to doses. Satisfactory dose-effect calibration curve is observed after low dose irradiation of human lymphocytes in vitro. When plotting on a linear scale against radiation dose, the line of best fit was $Y=(0.02{\pm}0.0009)+(0.033{\pm}0.010)D+(0.012{\pm}0.012)D^2$. The dose-response curve for MN induction immediately after irradiation was linear-quadratic and has a significant relationship between the frequencies of MN and dose. These data show a trend towards increase of the numbers of MN with increasing dose. The number of MN in lymphocytes that were observed in the control group is $0.1610{\pm}0.0093/cell$. Accordingly, MN assay in human peripheral lymphocytes could be a useful in viva model for studying radio-protective drug sensitivity or screening test, microdosimertic indicator and radiation-induced target organ injury. Since MN assay is simple, rapid and reproducible, it will also be a biodosimetric indicator for individual dose assessment after accidental exposure.

• Journal of Trauma and Injury
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• v.23 no.2
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• pp.57-62
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• 2010

Purpose: This study analyzed the characteristics of stable pelvic bone fractures with intra-abdominal solid organ injury. Methods: Medical records were retrospectively reviewed from January 2000 to December 2009 of patients with stable pelvic bone fractures. A stable pelvic bone fracture according to Young's classification is defined as a lateral compression type I and antero-posterior compression type I. Subjects were divided into two groups, one with (injured group) and one without (non-injured group) intra-abdominal solid organ injury, to evaluate the dependences of the characteristics on the presence of an intra-abdominal solid organ injury. Data including demographics, mechanism of injury, initial hemodynamic status, laboratory results, Revised Trauma Score (RTS), Abbreviated Injury Scale (AIS), Injury Severity Score (ISS), amount of transfusion, admission to intensive care unit (ICU), and mortality were analyzed. Results: The subjects were 128 patients with a mean age of 42 years old, of whom were 67 male patients (52.3%). The injured group had 21 patients(16.4%), and the most frequent injured solid organ was the liver. Traffic accident was the most common mechanism of injury and lateral compression was the most common type of fracture in all groups. Initial systolic blood pressure was lower in the injured group, and the ISS was greater in the injured group. Arterial pH was lower in the injured group, and shock within 24 hours after arrival at the emergency department was more frequent in the injured group. Transfused packed red blood cells within 24 hours were 8 patients(38.1%) in the injured group and 11 patients(10.3%) in the non-injured group. Conservative treatment was the most common therapeutic modality in all groups. Stay in the ICU was longer in the injured group, and three mortalities occurred. Conclusion: There is a need to decide on a diagnostic and therapeutic plan regarding the possibility of intra-abdominal solid organ injury for hemodynamically unstable patients with stable pelvic bone fractures and for patients with stable pelvic bone fractures along with multiple associated injuries.

• Korean Journal of Environmental Agriculture
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• v.36 no.4
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• pp.288-292
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• 2017

BACKGROUND: Silicon tetrachloride reacts with moisture in the atmosphere to generate hydrogen chloride, which affects the environment. Since silicon tetrachloride and its by-products are dispersed in the atmosphere in a short time after the silicon tetrachloride release into the atmosphere, it is difficult to directly assess the extent of environmental impact. In the present study, the exposure test of silicon tetrachloride or hydrogen chloride was examined in order to establish the criterion of the range affected by the silicon tetrachloride release, and the actual crops in the area exposed to silicon tetrachloride leakage were analyzed. METHODS AND RESULTS: For the experiment of exposure to silicon tetrachloride or hydrogen chloride, the leaves of red-pepper and corn were used in glass sealed containers. In the actual accident area, 59 samples from 10 different kinds of crops were collected. The pretreatment of the sample was performed by freezing and grinding, and then extracted using distilled water. The pH and concentration of chloride ($Cl^-$) ion of the extracted solution were measured using pH meter and ion chromatograph, respectively. CONCLUSION: Exposure to silicon tetrachloride caused visible damage, increasing the concentration of chloride ion, and decreasing the pH as well as hydrochloric acid. In the actual crops of the affected area, the tendency was the same as the result of the laboratory test, and the range of influence could be estimated through the concentration of $Cl^-$ ion over 2,000 mg/kg, and the correlation evaluation between the concentration of $Cl^-$ and pH. Therefore, the concentration of $Cl^-$ ion and the correlation between $Cl^-$ and pH would be considered as the factors to estimate the influence range of silicon tetrachloride release.

• Archives of Reconstructive Microsurgery
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• v.18 no.2
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• pp.62-66
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• 2009

Purpose: Despite the free tissue transfer using microsurgical technique being the current trend of soft tissue reconstruction of the hand, the pedicled groin flap has the advantage to provide coverage for the mangled hand without necessitating the use of a damaged arterial system and also providing the benefit of saving the arterial system for later free tissue transfer. This report presents the author's experience using pedicled groin flap in four cases of mangled hands with massive bone and soft tissue defects requiring later thumb reconstruction with the free wrap around flap. Materials and methods: The patients' age ranged from 30 to 51 years; three patients were male and one was female. The causes of mangled hand included two machinery crush injuries, one laboratory explosion and one motor vehicle accident. While evaluating the post-operative results, factors like flap survival, complications, stability in opposition, pinch power and 2 point discrimination were taken into account. Results: All massive soft tissue defects of the hands were completely covered with pedicled groin flap successfully. The reconstructed thumb using free wrap around flap did not have any limitation in opposition. There was no occurrence of post-operative infection and all the flaps survived completely. The average pinch power was 70% of the contralateral intact thumb and average 2 point discrimination was 10 mm. Conclusion: The pedicled groin flap for the reconstruction of the massive soft tissue defects of the hand with subsequent reconstruction of the thumb with a wrap around flap is a very useful procedure. The combined use of pedicled groin flap and wrap around flap allows adequate coverage of sizable soft tissue defects and functional thumb opposition in cases of reconstruction of the mangled hands.

• Journal of the Korean Institute of Gas
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• v.17 no.4
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• pp.18-25
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• 2013

It may occur health hazards or death by suffocation or acute poisoning in case of oxygen deficiency in ambient or exposure to harmful gas. As a part of accident prevention, we studied the change of activity and lethal dose by changing the concentration of several hazardous gas with inhalation exposure chamber and laboratory animals. We investigated the lethality and motility change during either the 4 hrs whole body exposure to oxygen, nitrogen, toluene, $H_2S$, CO and 48 recovery. As results, it is estimated that 5% oxygen concentration as lethal concentration and 5.5% as $LC_{50}$ (rat, 4 hrs) with statistics for dose-response. The results of lethality in oxygen deficient condition (approximately 6%), the lethalities were 40%, 20% with 20 ppm $H_2S$, 600 ppm CO respectively, and was not increased the lethality with 8% CO. Thus, it was confirmed that the $H_2S$, CO had influence to lethal dose, while toluene had low fluence.

• International Journal of Highway Engineering
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• v.11 no.1
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• pp.13-24
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• 2009

This study developed a high strength and performance concrete pavement material with low shrinkage and reflection of sunlight. Based on the literature review, a new mix-design of applying flash ash to improve the strength and performance of the concrete as well as to reduce the dry shrinkage is suggested. In addition, adding black pigment to reduce the reflection and technique of applying OAG (Optimized Aggregate Gradation) is also included. The result of the laboratory experiment indicates that the brightness and the reflection, which depends on the ratio of black pigment addition, did not deviate from the normal range. When OAG is considered for the mix-design, the strength and performance of the concrete improved greatly. In addition, the mix-design using fly ash reduced the dry shrinkage of concrete and improved the resistance to the permeation of chloride ion. Furthermore, the mix-design, which uses fly ash (25% replacement) and black pigment (3% addition) with the application of OAG, is found to be the most effective mix to reduce the shrinkage and reflection as well as improving the strength and performance of the concrete. The result of an economic analysis indicates that the initial construction cost of this proposed mix is more expensive than that of normal concrete pavement material. However, it can be more economic in the long run because the normal concrete pavement material is likely to cost more due to higher probability of maintenance and repair and higher social cost due to traffic accident, etc.

• Journal of Korean Society of Water and Wastewater
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• v.30 no.6
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• pp.653-662
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• 2016

Recently, advanced metering infrastructure (AMI) has been recognized as a core technology of smart water grid, and the relevant market is growing constantly. In this study, we developed all-in-one smart water meter of the AMI system, which was installed on the test-bed to verify both effectiveness and field applicability in office building water usage. Developed 15 mm-diameter smart water meter is a magneto-resistive digital meter, and measures flow rate and water quality parameters (temperature, conductivity) simultaneously. As a result of the water usage analysis by installing six smart water meters on various purposes in office building water usage, the water usage in shower room showed the highest values as the 1,870 L/day and 26.6 liter per capita day (LPCD). But, the water usage in laboratory was irregular, depending on the many variables. From the analysis of the water usage based on day of the week, the water usage on Monday showed the highest value, and tended to decrease toward the weekend. According to the PCA results and multivariate statistical approaches, the shower room (Group 3) and 2 floor man's restroom sink (Group 1-3) have been classified as a separate group, and the others did not show a significant difference in both water use and water quality aspects. From the analysis of water usage measured in this study, the leak or water quality accident did not occur. Consequently, all-in-one smart water meter developed in this study can measure flow rate and water quality parameters (temperature, conductivity) simultaneously with effective field applicability in office building water usage.

• Korean Chemical Engineering Research
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• v.57 no.6
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• pp.781-789
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• 2019

There are frequent accidents by chemicals during laboratory experiments and pilot plant and reactor operations. It is necessary to find and comprehend relevant information to prevent accidents before starting synthesis experiments. In the process design stage, reaction information is also necessary to prevent runaway reactions. Although there are various sources available for synthesis information, including the Internet, it takes long time to search and is difficult to choose the right path because the substances used in each synthesis method are different. In order to solve these problems, we propose an intelligent synthetic path search system to help researchers shorten the search time for synthetic paths and identify hazardous intermediates that may exist on paths. The system proposed in this study automatically updates the database by collecting information existing on the Internet through Web scraping and crawling using Selenium, a Python package. Based on the depth-first search, the path search performs searches based on the target substance, distinguishes hazardous chemical grades and yields, etc., and suggests all synthetic paths within a defined limit of path steps. For the benefit of each research institution, researchers can register their private data and expand the database according to the format type. The system is being released as open source for free use. The system is expected to find a safer way and help prevent accidents by supporting researchers referring to the suggested paths.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.32 no.1
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• pp.78-88
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• 2022

Objectives: To develop the smart sensor to protect worker's health from chemical exposure by adopting ICT (Information and Communications Technology) technologies. Methods: To develope real-time chemical exposure monitoring system, IoT (Internet of Things) sensor technology and regulations were reviewed. We developed and produced smart sensor. A smart sensor is a system consisting of a sensor unit, a communication unit, and a platform. To verify the performance of smart sensors, each sensor has been certified by the Korea Laboratory Accreditation Scheme (KOLAS). Results: Chemicals (TVOC; Total Volatile Organic Compounds, Cl₂: Chlorine, HF: Hydrogen fluoride and HCN: Hydrogen cyanide) were selected according to a priority logic (KOSHA Alert, acute poisoning statistics, literature review). Notifications were set according to OEL (occupational exposure limit). Sensors were selected based on OEL and the capabilities of the sensors. Communication is designed to use LTE (Long Term Evolution) and Wi-Fi at the same time for convenience. Electronic platform were applied to build this monitoring system. Conclusions: Real-time monitoring system for OEL of hazardous chemicals in workplace was developed. Smart sensor can detect chemicals to complement monitoring of traditional workplace environmental monitoring such as short term and peak exposure. Further research is needed to expand the scope of application, improve reliability, and systematically application.