• Journal of the Korea Furniture Society
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• v.23 no.2
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• pp.152-162
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• 2012

The color changing of the wood surface was tested by accelerated weathering test that can simulate the outdoor condition with short period. In early parts of accelerated weathering test, weight and volume of specimen all were increased due to the moisture evaporation by its high temperature and illumination level, but weight and volume of specimen all were decreased from middle parts to last. However, significancy showed between control group and accelerated weathering test group in terms of weight and volume. According to the results of color-difference meter, in the early parts of the accelerated weathering test lightness, redness and yellowness all showed a clear increasing or decreasing trend. However, after three weeks all values were almost never change. Until the early parts of the test, lightness was decreased and there was not a considerable change after three weeks in the test. Redness showed a some change in early parts of the test, but this also showed not great change after middle parts of the test as like lightness. Yellowness also showed same pattern. These results could be verified through the visual inspection. As like weight and volume, significancy showed between control group and accelerated weathering test group in terms of color-difference test. In all accelerated weathering test group, color-differences of after test was lower than that of before test. To correctly analyze this cause, more additional research will be need on each of temperature, humidity and illumination factors.

• 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.

• Journal of the Korean Wood Science and Technology
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• v.21 no.2
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• pp.9-14
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• 1993

Weathering of wood in a region of acid rain was performed by the test which thin veneers of Sitka spruce were exposed to outdoor weathering for a total of 18 weeks, with a daily soaking for 30 minutes in acidified water in the pH range 2~5.6. The weathering measured by weight loss and loss in maximum failure load in tension was accelerated by the increase in the acidity of acidified water and in the period of outdoor exposure. It was also shown that the weathering was accelerated even with low acidic conditions in the case of long exposure period, although the weathering was rapidly accelerated with high acidic conditions. When compared the degree of weight loss with that of loss in failure load by weathering, the latter was much greater. From the results of this research, it could be concluded that at pH 4.0 or below of precipitation, the acceleration of weathering of exterior wood would become serious problems, which would be caused deterioration in performance of exterior wood.

• Journal of the Korea Furniture Society
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• v.26 no.4
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• pp.392-397
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• 2015

This study was carried out to analyze the effects on mechanical properties of deteriorated wood member by outdoor condition. The surface color, mechanical properties and structural stability of traditional wooden structures, exposed in water and UV, could be changeable. For the purpose, accelerated weathering test based on outdoor condition was carried out. The weathering time levels were composed 0, 500, 1000, 1,500 and 2,000 hours and mechanical properties were evaluated on each specimen according to weathering time level. Bending properties were decreased on weathering but recovered after 1,000 hours. Fatigue and impact strength were decreased to 1,000 hours and did not changed since then. Abrasion resistance was minimized in 1,000 hours. This results could be utilized for effectively stability management of traditional wooden structures and members.

• Tunnel and Underground Space
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• v.19 no.4
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• pp.318-327
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• 2009

Accelerated weathering tests was executed to understand the physical characteristics of rocks in Dokdo. For the tests rock samples including trachytic andestes, andesite dyke and ash tuff were taken in place. Double soxhlet extractor and peristatic pump were used for accelerating the weathering processes. After the tests for 4 months, the variations of superficial structure, microscopic structure and strength of rock samples were observed.

• Elastomers and Composites
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• v.51 no.4
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• pp.350-354
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• 2016

The surface properties of poly(methyl methacrylate) (PMMA) were investigated after accelerated weathering. Glossinesses, contact angles, surface free energies, thermal stability, and mechanical properties were investigated. The glossiness of the weathered PMMA was decreased with increasing exposure time. Contact angles and surface free energies were not overtly changed because the amount of oxygen on the surface was remained. PMMA was compounded with anti-block and antistatic agents using a co-rotating twin screw extruder to improve the durability. The PMMA composites showed better glossinesses after accelerated weathering while maintaining the contact angles, surface energy, thermal stability, and mechanical properties without significant changes.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.243-247
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• 2003

The effect of accelerated weathering(UV) on three type of ethylene propylene diene monomer(EPDM) composite used for higher voltage insulator were investigated by weather-emoter. For weatherability of EPDM composite, surface resistance, dielectric breakdown strength, change of contact angle, surface composition were measured according to UV accelerated weathering time. From the resort of the measurement of surface resistivity, contact angle of EPDM composite decreased and showed chalking and cracking phenomenon when UV weathweing time was for 1500 h and 2000 h. The analysis of surface atomic composition indicated that surface aluminiu(Al) content was detected due to chalking phenomenon after 1500 h of UV weathering, Oxygen content of all composite increased due to the oxidation.

• Journal of the Korea Furniture Society
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• v.26 no.3
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• pp.262-266
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• 2015

This study was carried out to analyze the surface color change according to the weathering time. The surface color of material was one of evaluation indexes in exposure experiment. For the purpose, accelerated weathering test was performed with wood. The weathering time level was composed with 0, 500, 1000, 1500 and 2000 hours and color difference was estimated with the color difference meter. The surface color was changed to 500 hours that lightness and redness were decreased and yellowness was increased. However it did not changed after 500 hours. It means that the surface color could be the evaluation index of deterioration of the wood but it means very little after certain time.

• Journal of the Mineralogical Society of Korea
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• v.17 no.1
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• pp.23-35
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• 2004

The weathering characteristics of periodically submerged sedimentary rocks in the Sayeon dam, Ulsan was examined by field work, electron probe micro-analysis, X-ray diffraction, and X-ray fluorescence spectrometry. Analysis of fracture zone and exfoliation showed the submerged sedimentary rocks have undergone severe mechanical weathering. Mechanical weathering in the water-rock interface accelerated chemical weathering, such as dissolution and alteration of the most of minerals except for quartz in the weathering zone. The dissolution of carbonates specially calcite, is remarkable creating the cavities, whereas formation of minerals including clay minerals is not active. The sedimentary rocks have been periodically submerged for a certain period of time, and have repeated freezing and thawing. This mechanical weathering favored infiltration, which accelerated mineral dissolution. The high content of easily soluble carbonate of the sedimentary rocks is likely the major cause of intense chemical weathering. The dissolved elements within the infiltrated water interrupted the occurrence of clay and weathering minerals, and expend fractures by infiltrated water accelerated weathering process.

• Journal of the Korean Wood Science and Technology
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• v.31 no.4
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• pp.44-49
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• 2003

This study was carried out to evaluate the weathering durability of waterborne preservative (AAC, ACQ, CCA, CuAz) treated Japanese red pine (Pinus densiflora S. et Z.) sapwood samples by accelerated weathering, and to find out the factor of stability. When considered the color changes, weight losses, surface degradation, and microstructure changes due to weathering, ACQ-, CCA-, and CuAz-treated samples were durable against weathering; the weathering durability of AAC-treated samples was poor and similar to untreated controls. The lignin content in aqueous extracts collected from ACQ-, CCA-, and CuAz-treated samples during weathering was lower than that from untreated and AAC-treated ones. From these findings, we might concluded that weathering durability of ACQ-, CCA-, and CuAz-treated samples was enhanced by the fixation of preservative component(s) onto the lignin structure, which is very susceptible to weathering.