• Journal of the Korean Society for Nondestructive Testing
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• v.28 no.2
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• pp.151-156
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• 2008

Many kinds of mass spectrometer type leak detectors have been widely used for detecting leak of vacuum processes in semiconductor and display industries etc. The leak detectors should be often calibrated by the permeation type standard leak in order to ensure accurate and reproducible leak measurement. We have developed a comparative calibration system for permeation type standard leak by using mass spectrometer type leak detector and specification of the calibration method. Following this technique the reliable calibration for leak standard ran be performed even in fields.

• Journal of Ocean Engineering and Technology
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• v.22 no.4
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• pp.40-45
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• 2008

This paper describes the effects of fly ash replacement on the water tightness of antiwashout underwater concrete, which replaced the cement with fly ash from 0% to 30%. The experimental work was performed to find out the depth of permeation of concrete specimens cast in air and cured in 23 $^{\circ}C$ tap water using an open center pressure type of water permeation tester. The results showed that the permeation depth values of antiwashout underwater concrete were deeper than normal concrete, but that an admixture using fly ash during antiwashout underwater concrete casting in air made it more watertight than normal concrete according to the water permeation testing. SEM observations of the specimens of fly ash antiwashout underwater concrete showed that it wasmore packed with structures because of the pozzolan reaction of the fly ash and cement.

• Corrosion Science and Technology
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• v.16 no.4
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• pp.209-225
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• 2017

Development of high strength steel requires proper understanding of hydrogen behavior since the higher the steel strength the greater the susceptibility of hydrogen assisted cracking. This paper provides a brief but broad overview on hydrogen entry and transport behavior of high-strength ferritic steels. First of all, hydrogen absorption, diffusion and trapping mechanism of the steels are briefly introduced. Secondly, several experimental methods for analyzing the physical/chemical nature of hydrogen uptake and transport in the steels are reviewed. Among the methods, electrochemical permeation technique utilized widely for evaluating the hydrogen diffusion and trapping behavior in metals and alloys is mainly discussed. Moreover, a modified permeation technique accommodating the externally applied load and its application to a variety of steels are intensively explored. Indeed, successful utilization of the modified permeation technique equipped with a constant load testing device leads to significant academic progress on the hydrogen assisted cracking (HAC) phenomenon of the steels. In order to show how the external and/or residual stress affects mechanical instability of steel due to hydrogen ingress, the relationship among the microstructure, hydrogen permeation, and HAC susceptibility is briefly introduced.

• Proceedings of the Korean Fiber Society Conference
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• 1993.06b
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• pp.115-119
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• 1993

• Journal of Auto-vehicle Safety Association
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• v.16 no.1
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• pp.49-54
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• 2024

This paper provides an analysis of the experimental procedures and results to ensure the reliability of the system manufactured for testing the hydrogen permeability of a 175 L compressed hydrogen container for a hydrogen bus. Based on the hydrogen permeability standard of 6 cc/(h·L), it was injected into the permeability test chamber at 10% intervals, and the permeated hydrogen concentration according to the injected amount was measured and compared with the actual amount of hydrogen permeated. As a result of the experiment, the measured value represented 96.34% of the actual permeation amount, which can be used as basic data for the hydrogen bus vessel permeability test system being built in Korea.

• Journal of the Korean institute of surface engineering
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• v.55 no.6
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• pp.383-389
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• 2022

Natural(outdoor) and accelerated(artificial) weathering tests were performed to investigate their influence on polycarbonate. The polycarbonate materials were prepared of various formulations divided into three batches, with existing, development materials1, development materials2, containing mixture of UV additives. Weathering tests were carried out as outdoor weathering(Seosan, South Korea) and accelerated weathering(xenon-arc), and the results analysis were evaluated based on yellow-index(YI), scanning electron microscope(SEM/EDS), energy dispersive x-ray spectroscopy(XRD), and gel permeation chromatography(GPC). Among the three materials, processing method development materials1 with UV stabilizer was excellent in weathering. This study can provide basic data for standardization of development and performance evaluation on livestock barn roof.

• Environmental Engineering Research
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• v.21 no.1
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• pp.22-28
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• 2016

The aim of this study was to recycle the waste livestock blood as one of the waste biomass by turning proteins, the main constituent of blood, into effective biological resources like amino acid. Ultrasonic technology was applied to solubilize the proteins in the waste livestock blood. And of the multiple ultrasonic frequencies tested, 20 kHz was confirmed to yield the highest solubilization rate. The optimum pretreatment conditions were determined to be 30-min treatment at an ultrasonic irradiation density of 0.5 W/mL, which resulted in a solubilization rate of 96.01%. Also, a gel permeation chromatography (GPC) confirmed that a large amount of proteins were solubilized, and in an experiment where ultrasonic treatment was applied to kill bacteria, death rates of general bacteria and total coliforms were found to be reduced by 99.93% and 100%, respectively. Based on these results, ultrasonic technology was confirmed to be a crucial part of treating and recycling the proteins in waste livestock blood.

• Safety and Health at Work
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• v.15 no.2
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• pp.228-235
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• 2024

Background: Glove reuse poses risks, as chemicals can persist even after cleaning. Decontamination methods like thermal aeration, recommended by US OSHA, vary in effectiveness. Some studies show promising results, while others emphasize the importance of considering both permeation and tensile strength changes. This research advocates for informed glove reuse, emphasizing optimal thermal aeration temperatures and providing evidence to guide users in maintaining protection efficiency. Methods: The investigation evaluated Neoprene and Nitrile gloves (22 mils). Permeation tests with toluene and acetone adhered to American Society for Testing Materials (ASTM) F739 standards. Decontamination optimization involved aeration at various temperatures. The experiment proceeded with a maximum of 22 re-exposure cycles. Tensile strength and elongation were assessed following ASTM D 412 protocols. Breakthrough time differences were statistically analyzed using t-test and ANOVA. Results: At room temperature, glove residuals decreased, and standardized breakthrough time (SBT)₂ was significantly lower than SBT₁, indicating reduced protection. Higher temperature decontamination accelerated residual removal, with ∆SBT (SBT₂/SBT₁) exceeding 100%, signifying restored protection. Tensile tests showed stable neoprene properties postdecontamination. Results underscore thermal aeration's efficacy for gloves reuse, emphasizing temperature's pivotal role. Findings recommend meticulous management strategies, especially post-breakthrough, to uphold glove-protective performance. Conclusions: Thermal aeration at 100℃ for 1 hour proves effective, restoring protection without compromising glove strength. The study, covering twenty cycles, suggests safe glove reuse with proper decontamination, reducing costs significantly. However, limitations in chemical-glove combinations and exclusive focus on specific gloves caution against broad generalization. The absence of regulatory directives on glove reuse highlight the importance of informed selection and rigorous decontamination validation for workplace safety practices.

• Geomechanics and Engineering
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• v.10 no.4
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• pp.527-546
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• 2016

This paper discusses improvements of compressibility, permeability, static and liquefaction strengths of in-situ soils by grouting. Both field testing and laboratory evaluation of the on-site samples were conducted. The improvement of soils was influenced by two main factors, i.e., the grout materials and the injection mechanisms introduced by the field grouting. On-site grout mapping revealed the major mechanism was fracturing accompanied with some permeation at deeper zones of sandy soils, where long-gel time suspension grout and solution grout were applied. The study found the compressibility and swelling potential of CL soils at a 0.5 m distance to grout hole could be reduced by 25% and 50%, respectively, due to the grouting. The effect on hydraulic conductivity of the CL soils appeared insignificant. The grouting slightly improved the cohesion of the CL soils by 10~15 kPa, and the friction angle appeared unaffected. The grouting had also improved the cohesion of the on-site SM soils by 10~90 kPa, while influences on the friction angle of soils were uncertain. Liquefaction resistances could be enhanced for the sandy soils within a 2~3 m extent to the grout hole. Average improvements of 40% and 20% on the liquefaction resistance were achievable for the sandy soils for earthquake magnitudes of 6 and ${\geq}7.5$, respectively, by the grouting.

• Journal of the Korean Applied Science and Technology
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• v.34 no.2
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• pp.225-235
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• 2017

In this study, we investigated the effect on the increase of In vitro skin permeation experiments and In-vivo skin whitening efficacy using a O/W nanoemulsion produced via PIC(Phase Inversion Composition) with 1,3-di(pentyloxyl)benzene. skin permeation experiments of RS-nanoemulsion formulated with selected condition was evaluated compared to mineral oil containing 1,3-di(pentyloxyl)benzene and normal O/W type RS-emulsion. Compared to mineral oil with 1,3-di(pentyloxyl)benzene and RS-emulsion. RS-Nanoemulsion has a statistically significant high percutaneous absorption in terms of index substance, which is 1,3-di(pentyloxyl)benzene. In vivo test were prepared in the system of O/W cream containing RS-nanoemulsion. There was no adverse reactions in both samples. After 8 weeks, the subjects was evaluated by a dermatologist's scoring and Chromameter. In conclusion, the testing product showed statistically improvement (p<0.05) compared to the controlled product and proved its whitening efficacy.