• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.1
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• pp.3-10
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• 2019

The purpose of this paper is to find the fire-protection method for keeping on the bond capacity of Near-Surface-Mounted (NSM) FRP under high temperature. Experiments have been carried out to evaluate the bond capacity of NSM FRP by using CFRP-plates and to confirm the heat transfer to the concrete block when the refractory insulation is attached to the surface of NSM FRP. Bond test of NSM FRP under room temperature was conducted to obtain the maximum bond strength. And then a heating tests were carried out with keeping the bond stress of 30% of the maximum bond strength. As a result, the bond capacity of NSM FRP was disappeared when the temperature at epoxy reached to its glass transition temperature (GTT). In order to secure the bond capacity of the NSM FRP, it is necessary to protect the front as well as side by using insulation materials.

• 대한방사선방어학회:학술대회논문집
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• 2010.04a
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• pp.166-167
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• 2010

• Journal of the Korea Safety Management & Science
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• v.10 no.4
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• pp.105-109
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• 2008

The purpose of this study is to distinguish the causes of broken glass on doors or windows when it is originally kept among the remains on the floor in fire site - whether it was broken due to heating or outer power-through test and characteristics of the broken plane including the pattern on the plane. Addition to it, the study tries to find characteristics to judge the point and direction of breakdown through the analysis of glass broken by outer power. With two assumed causes - a) breakdown due to heating and b) breakdown due to outer power-3 pieces of glass plates ($30cm{\times}30cm{\times}5mm$) were tested for each case, getting the results as following: First, for the glass broken due to the change of temperature, the broken plane is of slow and smooth curve without any pattern. Second, for the glass broken due to outer power, with the impact point as the center, the glass shows breakdown of radial type and the side shows breakdown of near-perpendicular type. The far the broken piece is from the impact point, the bigger the size is. The broken piece at the impact point is of long triangle type and the two long planes of the triangle shows semi-arc with the center of breakdown point and the other plane shows opposite pattern. Third, when glass that is damaged by outer power is heated, damaged forms and side patterns of the glass that is damaged by outer power are heated and disappeared.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2012.04a
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• pp.333-336
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• 2012

ISO 13784-1 sandwich panel tests were conducted by FILK, KICT in Korea, SP in Sweden and CSIRO in Australia. Sandwich panels composed of steel sheets, EPS and glass wool supplied by FILK were tested. Mainly heat release rate was compared and equlity of distribution also analyzed on the point of statistical view based on ISO.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2011.11a
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• pp.201-204
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• 2011

ISO 13784-1 sandwich panel tests were conducted by FILK, KICT in Korea, SP in Sweden and CSIRO in Australia. Sandwich panels composed of steel sheets, EPS and glass wool supplied by FILK were tested. Mainly heat release rate was compared and equality of distribution also analyzed on the point of statistical view based on ISO.

• Nuclear Engineering and Technology
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• v.53 no.6
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• pp.2025-2037
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• 2021

The influence of lead cations on natural quartz (QZ) from Egypt as a glass shielding material for the composition with nominal formula (10Na₂O - (90 - x) QZ - xPbO (where x = 30, 35, 40, 45 and 50 mol %)) was examined. The studied samples are synthesized via the melt quenching method at 1050 ℃. The X-ray diffraction XRD patterns were confirmed the glass nature for studied samples. Moreover, the optical properties, and the transparency for all compositions were examined by UV-Vis spectroscopy. Also, the major elemental composition of the natural quartz were estimated via the X-ray fluorescence (XRF) technique. Further, the density and molar volume were determined. Furthermore, the nuclear shielding parameters such as, mass attenuation coefficient, effective atomic number, electronic density, the total atomic, and electronic cross sections as well as the mean free path, and the half value layer with different gamma ray energies (81 keV-1407 keV) were calculated. Besides, the results showed that the shielding behavior towards the gamma ray radiation for all glass samples was increased as the increment in PbO concentration in the glass system.

• Corrosion Science and Technology
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• v.9 no.5
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• pp.201-208
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• 2010

Epoxy coatings cured by different amine based curing agents have been prepared. Atomic force microscopy (AFM) has been used to monitor the surface topology changes of epoxy coatings before and after hygrothermal cyclic test. The glass transition temperature ($T_g$) and coefficient of thermal expansion (CTE) of the epoxy coating were measured by Thermo-mechanical Analysis (TMA). The Electrochemical impedance spectroscopy (EIS) with hygrothermal cyclic test has been introduced to evaluate the corrosion protection of the epoxy coatings. In conclusion, thermal properties of epoxy coatings were in good agreement with the results of corrosion protection of epoxy coated carbon steel obtained result by EIS with hygrothermal cyclic test. The relationship between thermal properties, surface roughness changes and corrosion protection of epoxy coatings are discussed in this study.

• Nuclear Engineering and Technology
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• v.54 no.2
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• pp.479-485
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• 2022

At the Korea Institute of Radiological and Medical Sciences, physical human phantoms were developed to evaluate various radiation protection quantities, based on the mesh-type reference computational phantoms of the International Commission on Radiological Protection. The physical human phantoms were fabricated such that a radiophotoluminescent glass dosimeter (RPLGD) with a Tin filter, namely GD-352M, could be inserted into them. A Tin filter is used to eliminate the overestimated signals in low-energy photons below 100 keV. The measurement uncertainty of the RPLGD reader system based on GD-352M should be analyzed for obtaining reliable protection quantities before using it for practical applications. Generally, the measurement uncertainty of RPLGD systems without Tin filters is analyzed for quality assurance of radiotherapy units using a high-energy photon beam. However, in this study, the measurement uncertainty of GD-352M was analyzed for evaluating the protection quantities. The measurement uncertainty factors in the RPLGD include the reference irradiation, regression curve, reproducibility, uniformity, energy dependence, and angular dependence, as described by the International Organization for Standardization (ISO). These factors were calculated using the Guide to the Expression of Uncertainty in Measurement method, applying ISO/ASTM standards 51261(2013), 51707(2015), and SS-ISO 22127(2019). The measurement uncertainties of the RPLGD reader system with a coverage factor of k = 2 were calculated to be 9.26% from 0.005 to 1 Gy and 8.16% from 1 to 10 Gy. A blind test was conducted to validate the RPLGD reader system, which demonstrated that the readout doses included blind doses of 0.1, 1, 2, and 5 Gy. Overall, the E_n values were considered satisfactory.

• Journal of Environmental Health Sciences
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• v.22 no.2
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• pp.43-57
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• 1996

To characterize worker's exposure to glass fibers, to find the correlation between airborne total dust concentrations and fiber concentrations and to recommend an appropriate evaluation method for worker's exposure to fibrous dusts in glass wool industry, we carried out this study. Average respirable fiber levels at five factories were 0.013-0.056 f/cc, and fairly below the OSHA PEL, 1 f/cc. A factory showed the lowest airborne fiber level, 0.013 f/cc, which was different significantly from those of other factories of which average fiber concentration was 0.046 f/cc. The cutting and grinding operations of insulation products resulted in higher airborne fiber cocentrations than any other processes(p<0.05). To characterize airborne fiber dimension, fiber length and diamter were determined using phase contrast microscope. The geometric means of airborne fiber lengths were $42-105 \mu m$. One factory had airborne fibers whose length distribution(GM = $105 \mu m$) was different from those of other factories(GM = $42-50 \mu m$). The percentages of respirable fibers less thinner than 3 gm were 38.9-90.9% at four factories, and two factories of them had the higher percentages than others. The findings explain for variation of airborne fiber diameters between factories. On the other hand, between the processes were the difference of fiber-length distributions observed. The cutting and grinding operations showed shorter fiber-length distributions than the fiber forming one. However, fiber-diameter distributions or respirable fiber contents were similar in all processes. The airborne fiber concentrations and the dust concentrations had relatively weak correlation(r=0.25), thus number of fibers couldn't be expected reliably from dust amount. Fiber count is appropriate for assessing accurate exposures and health effects caused by fibrous dusts including glass fibers. Ministry of Labor have established occupational exposure limit to glass fibers as nuisiance dust, but should establish it on the basis of respirable fiber concentration to provide adequate protection for worker's health

• Journal of the Korean Wood Science and Technology
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• v.49 no.1
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• pp.44-56
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• 2021

The carbonized length and area of plywood by the various spreading concentration of water glass and the type of additives were measured in accordance with the 45° MecKel's burner method of the fire protection performance standard of the Korean National Fire Agency. As a result of treating water glass with a concentration of 20 to 50 % on plywood, the flame retardancy tended to increase in proportion to the concentration of water glass. However, the optimum concentration of water glass was determined to be 30 % due to the efflorescence and sticky on the surface of plywood treated with high-concentration water glass of more than 30 %. As a result of the experiment by adding different proportions of additives to the water glass with concentration of 30 %, the standard of flame performance standard was satisfied under the conditions with the addition of 15% potassium hydroxide and 1-10% aluminum hydroxide, respectively. On the other hand, there were no significant difference in the flame retardancy by adding magnesium sulfate. These results about the flame retardancy of plywood by water glass and additives were expected to be basic data for improving flame-retardant treated wood.