• The Korean Journal of Community Living Science
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• v.22 no.4
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• pp.615-621
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• 2011

This study was conducted to evaluate of the protection efficiency in each part of developed pesticide-proof clothes by repeated washings. We investigated the effect of repeated laundering on mechanical properties of pesticide-proof clothes (not washed vs 5 times washed). We also examined pesticide infiltration rate into the pesticide-proof clothes by repeated laundering. The patches(TCL paper, surface area 50cm2)were attached to the inside of pesticide-proof clothes(head, chest, right upper-arm, right forearm, left thigh, left calf, back) which subjects had dressed in during pesticide spraying. The patches were detached from working clothes after work. For the extraction of pesticide in pesticide-proof clothes, sonication was applied for 30 min with methanol. The gas chromatography/mass spectrometry (GC/MS) was applied to identify the pesticide component. The results of this study are as follows: The force strength, water-vapour resistance and surface wetting resistance of pesticide-proof clothes decreased 5 times more in washed clothes. The concentration of pesticide was the highest in the head area of pesticide-proof clothes. In seven parts of TLC paper attached to the pesticide proof clothes, the concentration of pesticide was higher in the left thigh. The penetration part and concentration of pesticide increased as washing was repeated. Therefore the conclusion which can be drawn from this study is this: protection efficiency of pesticide-proof clothes decrease by repeated washings.

• Journal of Navigation and Port Research
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• v.44 no.3
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• pp.203-210
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• 2020

It is important to establish a strong system of agencies for protection against disasters. Also, the system of protection against disasters by the residents is necessary to be strengthen the system. We examined the roles of the protection agencies and the administrational institutions against disasters. The results are: 1) The mutual assistance agency relies on the administrational institution on a hardware surface., 2) On the software surface some systems of protection from disasters are under the control of the agencies, and some are under the control of the administrational institution., 3) The shelters are unable to meet the needs of people in any disaster. Thus, we should use of the existing institutions as evacuation areas., 4) The people working in the city in which they live tend to know the protocols of the disaster measures and to recognize the disaster maps well.

• Journal of Korea Ship Safrty Technology Authority
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• s.22
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• pp.34-53
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• 2007

In the case of hull material. large sized merchant ships are made of steel, on the other hand FRP or wood are used for small sized fishing boats. At present in Korea approximately 88,500 fishing boats are in operation of which 70% are made of FRP In the meantime, stainless steel is frequently used as shaft materials of the small-size FRP fishing boat. Namely, the kinds of shaft materials are STS 304(18Cr-8Ni), STS 316(18Cr-12Ni-2.5Mo steel) and STS 630(17Cr-Ni-Nb steel)etc. Among these things, STS 304 which is the cheapest and having ordinary corrosion resistance is most widely used as 2nd class shaft material. But, using STS 304 for shaft system material of the small-size FRP fishing boat on seawater environments entails a severe corrosion which causes shaft system troubles. Particularly, the corrosions tend to be concentrated of the stern and bow side, propeller shaft surface of inside of stern tube and the boat having no stern cooling pipe line system. As a solution for those problems, research on the ways to mitigate corrosion on the part of 2nd class stainless steel shaft have been undertaken. In the result, not only clarification for the reason of corrosion of the part of stainless steel shaft used mainly for the small-size FRP fishing boat was done, but also most optimal corrosion protection system was developed by experimenting shaft's protection simulation based of the electrochemical cathodic protection principle. In addition, verification through the field test on the optimal cathodic corrosion protection method by means of aluminum sacrificial anode was carried out. In this study, effective and economical shaft's protection system is suggested to the small-size FRP fishing boat operator by substantiating the results obtained from the research on the optimal cathodic protection.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.12
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• pp.5910-5916
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• 2011

Surface area of the steel member exposed to fire differs according to type and size of the section and the kind of the member, which shows a big difference in the temperature rise of the steel by fire. The section factor ($H_p$/A) is determined by factors such as type, size, and member of the steel and type of the fire protection material, and it is the criteria in determining thickness of the fire protection material. This study showed that the size of the steel increase regardless of the steel type, the section factor decrease. In the results on fire protection thickness of the steel according to the section factor, the efficiency of 1 hour fire protection was lower from 30 to 50% than the criteria. And there is the member, which have the thickness lower the minimum 27% in 2 hour fire protection, but it generally approached in the criteria. In case of H-shape steel, the efficiency of 3 hour fire protection was suitable for the criteria, but rectangular hollow steel section and circular hollow steel section were higher (5.0-17.5%) than the criteria.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.3
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• pp.25-31
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• 2019

This study was conducted to evaluate the penetration performance of the Silane Surface Protection Material (SSPM) penetrating the micro pore of concrete surface. The results was indicated microstructure, porosity and penetration depth of applied SSPM. Silica sand and conventional sand were used as fine aggregate in mortar. And liquid and cream types SSPM were used. The amounts of SPM were applied the 127, 255, 382, 510 g/m2 on the surface of mortar. The penetration depth specimens were made with $100{\times}30mm$ in according with KS F 4930. Penetration depth was evaluated according to KS F 4930, divide specimen and then spraying with water in cross section of specimens, and measure the depth of the non-wetted area. The microstructure result of mortar applied SSPM, it was obtained liquid and cream SSPM in mortar. The porosity results of SSPM application specimens were improved with than that of plain specimens. Test results indicated that the penetration depth of SPM were improved with increasing in amounts of SSPM. As a result of test, application of SSPM to concrete surface, it will improve durability.

• Journal of Radiation Protection and Research
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• v.34 no.1
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• pp.25-30
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• 2009

Micro-columnar CsI(Tl) is the most popular scintillator material which is used for many indirect digital X-ray imaging detectors. The light scattering at the surface of micro-columnar CsI(Tl) scintillator was studied to find the correlation between the surface roughness and the resultant image resolution of indirect X-ray imaging detectors. Using a commercially available optical simulation program, Light Tools, MTF (Modulation Transfer Function) curves of the CsI(Tl) film thermally evaporated on glass substrate with different thickness were calculated and compared with the experimental estimation of MTF values by the edge X-ray image method and CCD camera. It was found that the standard deviation value of Gaussian scattering model which is determined by the surface roughness of micro-columns could certainly change the MTF value of image sensors. This model and calculation methodology will be beneficial to estimate the overall performance of indirect X-ray imaging system with CsI(Tl) scintillator film for optimum design depending on its application.

• Journal of the Korean Institute of Gas
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• v.3 no.3 s.8
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• pp.23-28
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• 1999

Variation of explosion characteristics by the blocks in closed vessel was investigated to analyse the effect of the block volume(volume blockage) and the surface area of the blocks(ratio of block surface area to vessel volume). Volume and surface area of blocks in explosion vessel were changed by the combination of blocks. The volume of explosion vessels was 270 liter, and the LPG-air or NG-air mixtures were ignited by the electric spark. Explosion pressure was measured with the strain type pressure transducer. From the experimental results, explosion pressure was decreased by the increase of the volume blockage and the block surface area. And the decrease of explosion pressure was more affected by the volume blockage than the surface area.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.3
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• pp.397-404
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• 2021

In this study, it was reviewed that the effect of solid capsules on the quality of surface repair materials and the healing properties of long-term aging, as part of a study to utilize self-healing surface repair materials using solid capsules as repair materials. As a result of evaluation of the rheological properties of self-healing surface repair materials according to the mixing of solid capsules, plastic viscosity, yield stress, and table flow tended to decrease. In the case of compressive strength, 1MPa per 1% of the solid capsule decreased proportionally. As a result of evaluating the long-term healing properties, when 10% of solid capsules were mixed, a healing rate of 90% was shown at 28 days of healing, because the solid capsule was preserved even after 91 days of age had elapsed. after 91 days of healing, even in the case of 5% of solid capsules, a healing rate of 90% was shown.

• Journal of Radiation Protection and Research
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• v.48 no.1
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• pp.28-43
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• 2023

Background: High-fidelity meteorological data is a prerequisite for the realistic simulation of atmospheric dispersion of radioactive materials near nuclear power plants (NPPs). However, many meteorological models frequently overestimate near-surface wind speeds, failing to represent local meteorological conditions near NPPs. This study presents a new high-resolution (approximately 1 km) meteorological downscaling method for modeling short-range (< 100 km) atmospheric dispersion of accidental NPP plumes. Materials and Methods: Six considerations from literature reviews have been suggested for a new dynamic downscaling method. The dynamic downscaling method is developed based on the Weather Research and Forecasting (WRF) model version 3.6.1, applying high-resolution land-use and topography data. In addition, a new subgrid-scale topographic drag parameterization has been implemented for a realistic representation of the atmospheric surface-layer momentum transfer. Finally, a year-long simulation for the Kori and Wolsong NPPs, located in southeastern coastal areas, has been made for 2016 and evaluated against operational surface meteorological measurements and the NPPs' on-site weather stations. Results and Discussion: The new dynamic downscaling method can represent multiscale atmospheric motions from the synoptic to the boundary-layer scales and produce three-dimensional local meteorological fields near the NPPs with a 1.2 km grid resolution. Comparing the year-long simulation against the measurements showed a salient improvement in simulating near-surface wind fields by reducing the root mean square error of approximately 1 m/s. Furthermore, the improved wind field simulation led to a better agreement in the Eulerian estimate of the local atmospheric dispersion. The new subgrid-scale topographic drag parameterization was essential for improved performance, suggesting the importance of the subgrid-scale momentum interactions in the atmospheric surface layer. Conclusion: A new dynamic downscaling method has been developed to produce high-resolution local meteorological fields around the Kori and Wolsong NPPs, which can be used in short-range atmospheric dispersion modeling near the NPPs.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2008.11a
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• pp.195-201
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• 2008

When reinforced concrete is subjected to high temperature as in fire, there is deterioration in its properties of particular importance are loss in compressive strength, cracking and spalling of concrete, destruction of the bond between the cement paste and the aggregates and the gradual deterioration of the hardend cement paste. Assessment of fire-damaged concrete usually starts with visual observation of color change, cracking and spalling of the surface. In this paper, it was reported the trends of research and practical use on the Explosive Spalling Properties of the High-Strength Concrete.