• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.11a
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• pp.506-511
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• 2000

The aim of this study is to suggest a fundamental data to improve the sound insulation performance of floor. To achieve the aim of this study, 8 types of sound-absorbing and sound insulation materials were installed under the slab, and the floor systems were compared to the general floor system which was composed of slab, timber frame, gypsum board and wallpaper.

• Journal of the Korean Wood Science and Technology
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• v.44 no.5
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• pp.639-654
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• 2016

This study building materials by relates to human hazard assessment in accordance with the combustion gas SEM, the flame-retardant foam FTIR and cone calorimeter to configure the Forest products of MDF and preservative treated Lauan two kinds of Retardant styrofoam, Styrofoam, Urethane foam and gypsum board four kinds of plastics material by the combustion gas were each analyzed. MDF was burned to the structure of the wood and the glue evenly mixed combustion area preservative treated Lauan, kept constant even in the form of high heat to penetrate deep into the wood flame retardant agents. Retardant styrofoam is due to feed my Dropped dissolved inorganic flame retardant without the fire-stick and confirmed that the weak form of gypsum board, but keep the column. In MDF ammonia ($NH_3$), lethal concentration (750 ppm) compared to 795 ppm, preservative treated Lauan is carbon dioxide ($CO_2$) that was greater than 2.5 times the lethal concentration (100,000 ppm) to 256,965 ppm, the lethal concentration (500 ppm) of hydrogen chloride (HCl). The Urethane greater than 697 ppm, 434 ppm also greatly exceeding the nitrogen dioxide ($NO_2$) lethal concentration (250 ppm) in Retardant styrofoam and 398 ppm was released. It is confirmed that the human body is extremely harmful gas emitted from most of the materials to be utilized as basic data for evaluating the hazard-specific human future building material.

• Journal of Radiation Protection and Research
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• v.42 no.1
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• pp.33-41
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• 2017

Background: Phosphate rock and its by-product are widely used in various industries to produce phosphoric acid, gypsum, gypsum board, and fertilizer. Owing to its high level of natural radioactive nuclides (e.g., $^{238}U$ and $^{226}Ra$), the radiological safety of workers who work with phosphate rock should be systematically managed. In this study, $^{238}U$, $^{232}Th$, $^{226}Ra$, and $^{40}K$ levels were measured to analyze the transport characteristics of these radionuclides in the production cycle of phosphate rock. Materials and Methods: Energy dispersive X-ray fluorescence and gamma spectrometry were used to determine the activity of $^{238}U$, $^{232}Th$, $^{226}Ra$, and $^{40}K$. To evaluate the extent of secular disequilibrium, the analytical results were compared using statistical methods. Finally, the distribution of radioactivity across different stages of the phosphate rock production cycle was evaluated. Results and Discussion: The concentration ratios of $^{226}Ra$ and $^{238}U$ in phosphate rock were close to 1.0, while those found in gypsum and fertilizer were extremely different, reflecting disequilibrium after the chemical reaction process. The nuclide with the highest activity level in the production cycle of phosphate rock was $^{40}K$, and the median $^{40}K$ activity was $8.972Bq{\cdot}g^{-1}$ and $1.496Bq{\cdot}g^{-1}$, respectively. For the $^{238}U$ series, the activity of $^{238}U$ and $^{226}Ra$ was greatest in phosphate rock, and the distribution of activity values clearly showed the transport characteristics of the radionuclides, both for the byproducts of the decay sequences and for their final products. Conclusion: Although the activity of $^{40}K$ in k-related fertilizer was relatively high, it made a relatively low contribution to the total radiological effect. However, the activity levels of $^{226}Ra$ and $^{238}U$ in phosphate rock were found to be relatively high, near the upper end of the acceptable limits. Therefore, it is necessary to systematically manage the radiological safety of workers engaged in phosphate rock processing.

• Journal of Korean Society of Steel Construction
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• v.17 no.1 s.74
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• pp.33-43
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• 2005

This paper presents the test results and evaluations for the energy dissipation capacity and compressive performance of light-weight hybrid panels. A total of 26 full-scale specimens of light-weight hybrid panels were tested. The parameters include the presence of light-weight foamed mortar, the specific gravity of light-weight foamed mortar (0.6, 0.8, 1.0, 1.2), the finishing materials (light-weight foamed mortar, OSB [Oriented Strand Board], gypsum board), the shape of bracing (x, ~), and the size of panels (1P-900 mm 2,400 mm, 2P-1,800 mm 2,400 mm). The results of the cyclic tests are somewhat different from those of monotonic tests, due to the different specific gravity of light-weight foamed mortar. It was found from the compressive tests that the ultimate strength and initial stiffness are increased by means of light-weight foamed mortar (2~2.5 times in ultimate strength and 2~3 times in initial stiffness).

• Journal of Environmental Health Sciences
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• v.39 no.2
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• pp.138-143
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• 2013

Objective: Building materials can generate radon in indoor environments. This study aims to assess the radon concentrations of studio apartments around a university. Methods: 25 studio apartments around a University in Gyoungsan, Korea were measured for concentrations of radon. We evaluated the radon concentrations by using short-term continuous radon monitors at the studio apartments around the university, and analyzed the correlation between indoor radon concentration and factors affecting it, such as year of construction. Results: The average concentration of radon was 2.03 pCi/L(75.11 $Bq/m^3$)${\pm}1.34$ in the studio apartments. This radon level was lower than the radon standard for public use facilities in Korea and US EPA's standard of 4 pCi/L. However the measured radon levels were much higher than those previously reported in conventional dwellings. There was a statistically correlation between year of construction and radon concentrations in studio apartment buildings. Conclusion: It is suggested that recently built studio apartments might be constructed with phosphogypsum board that features higher radon emissions, and occupants are highly exposed to radon.

• Journal of the Korean Wood Science and Technology
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• v.43 no.4
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• pp.511-517
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• 2015

Sound absorption capability of the flame resistant treated sawdust-mandarin peel composite particleboard was were estimated by two microphone transfer function methods. The weight of flame resistant treated board slightly increased by the treatment. The treatment improved fire retardant performance by decreasing the charred area of flame resistant treated board. Sound absorption capabilities of flame resistant treated sawdust-mandarin peel composite particleboard, in the entire estimated frequency range of 500-6,400 Hz was slightly lower than those of the control specimen. Sound absorption capability of both the control and flame resistant treated sawdust-mandarin peel composite particleboards were higher than that of commercial gypsum boards, being widely used as a sound absorber for ceiling at the estimated frequency.

• Journal of Korean Society of Steel Construction
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• v.19 no.5
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• pp.455-462
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• 2007

The purpose of this paper is to evaluate experimentally the compressive performance of horizontal joints for light-weight hybrid panel in-filled with light-weight foamed mortar. The parameters include the presence of light-weight foamed mortar, the specific gravity of light-weight foamed mortar (0.8, 1.2), the finishing materials (light-weight foamed mortar, Oriented Strand Board [OSB], gypsum board), and the fixed shape of the hybrid panel. As the improved details for fixed end, the peak strength and the stiffness of the light-weight hybrid panel are enhanced as follows: 1.07-2.7 times in peak load, 15-24 times in initial stiffness. The peak strength of the light-weight hybrid panel obtained by the test result is in agreement with the calculations, which is the criterion value according to the domestic code.

• Journal of the Korean Wood Science and Technology
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• v.34 no.2
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• pp.22-29
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• 2006

On purpose to reduce accumulated moisture and to prevent moisture condensation in a light-frame wall, thermal characteristics and moisture behaviors were investigated for four different wall assemblies; a) typical wall, b) addition of vapor retarder between the insulation and the gypsum board, c) addition of air gap for natural ventilation behind the siding, d) composition with b) and c). Each wall was tested under two climate conditions; 1) $20^{\circ}C$, 50% RH (indoor) and $30^{\circ}C$, 85% RH (outdoor), 2) $30^{\circ}C$, 85% RH (indoor) and $20^{\circ}C$, 50% RH (outdoor).The results showed that the typical wall assembly had poor resistance against moisture intrusion from the inside of building. Outdoor and indoor humidity caused the moisture condensations on the inside of the siding and the back surface of the sheathing respectively. The addition of a vapor retarder did not give significant improvement in preventing the moisture intrusion.

• Journal of the Korea Furniture Society
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• v.28 no.4
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• pp.355-361
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• 2017

Indoor noise environment is an important factor when it comes to occupants comfort, especially in cafe. Results of the survey, 33.9% of occupants were feel unpleasant and sensitive about noise environment. Noise in cafe fluctuate depending on the finishing of both wall and ceiling, volume of the room, and the number of occupants in the room. Therefore, the noise meter device was used for measurement of various under conditions. Also, the subjective assessment of occupant noise was conducted through questionnaires. When the interior finish was exposed concrete, the maximum value of the noise measurement was 66.6 dB and the minimum value was 63 dB, respectively. Also, the result of subjective assessment of unpleasant noise were 5.43 and 4.96 point of 10 point of noise and echo, respectively. Otherwise, the interior finish was gypsum board, the maximum value of the noise measurement was 73.8 dB and the minimum value was 60.4 dB, respectively. Also, the result of subjective assessment of unpleasant noise were 3.88 and 3.95 point of 10 point of noise and echo, respectively. The results of the study showed that the noises and echoes in the cafes were lower than when did not.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.10B
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• pp.1876-1884
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• 1999

The next generation of wireless LAN AND PBX systems will make use of the unlicensecd band at 2.5 GHz. Deployment of these systems inside buildings requires and understanding of propagation characteristics within buildings. Because the wavelength is small compared to building dimensions, ray methods can be used to predict propagation, but they require knowledge of the transmission and reflection properties of walls. This paper reports on transmission measurements made at walls made of gypsum board on metal studs, and at concrete block walls using directive antennas. The measurements are found to give good agreement with theoretical results that account for the periodic nature of the wall structure.