• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.3
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• pp.56-61
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• 2012

The most common deterioration cause of concrete structures over the world is chloride ions attacks. Thus, service life modeling of concrete is a crucial issue in civil engineering society. Many studies on the durability of concrete have been accomplished, however, it is not easy to review literatures about environmental analysis. Since the durability of concrete depends on the properties of the surface concrete. micro-climatic condition which influences on surface concrete realistically should be considered. This study is devoted to analysis the micro-climatic condition of concrete structures, based on the in-situ monitoring of weather in marine environment. The effect of degree of saturation on chloride diffusivity of concrete is also examined. It is expected that the result of this work should be available for the prediction of chloride profile of marine concrete.

• Journal of Climate Change Research
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• v.9 no.4
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• pp.423-433
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• 2018

Particulate matter air pollution is a serious problem affecting human health and visibility. The variations in $PM_{10}$ concentrations are influenced by not only local emission sources, but also atmospheric circulation conditions. In this study, we investigate the temporal features of $PM_{10}$ concentrations in South Korea and the atmospheric circulation patterns associated with high concentration episodes of $PM_{10}$ during winter (December-January-February) 2001-2016. Based on those analyses, a Korea Particulate matter Index (KPI) is developed to represent the large-scale atmospheric pattern associated with high concentration episodes of $PM_{10}$. The atmospheric patterns are characterized by persistent high-pressure anomalies, weakened lower-level north-westerly anomalies, and northward shift of the upper-level meridional wind anomalies near the Korean Peninsula. To evaluate the change in occurrence of high concentration episodes of $PM_{10}$ under a possible future warmer climate, we apply KPI analysis to CMIP5 climate simulations. Here, historical and two representative concentration pathway (RCP) scenarios (RCP 4.5 and RCP 8.5) are used. It is found that the occurrence of atmospheric conditions favorable for high $PM_{10}$ concentration episodes tends to increase over South Korea in response to climate change. This suggests that large-scale atmospheric circulation changes under future warmer climate can contribute to increasing high $PM_{10}$ concentration episodes in South Korea.

• Journal of the Korean Society for Environmental Technology
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• v.19 no.6
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• pp.563-569
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• 2018

The efficiency of wastewater treatment using microalgae was investigated in this study, focusing on nutrients and flocculation. In the experiments for reducing nutrients by incubation of microalgae, the total phosphorus and total nitrogen were removed over 92 % and 99 %, respectively. The higher flocculation rates as the average values 94% of Poly Aluminum Chloride(PAC) and 92 % of $FeCl_3$ were presented for the flocculation experiments under the conditions of Auto-flocculation and various additives. Also, the optimal(minimal) concentrations for over 90 % of flocculation were 30 mg/L and 40 mg/L for PAC and $FeCl_3$, respectively.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.300-300
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• 2023

기후변화의 영향 중 하나인 무강우일수의 증가는 우리의 삶에 다양한 피해를 야기하고 있다. 영산강·섬진강권역은 2001년 이후 가장 심한 가뭄을 겪고 있으며, 이로 인해 하천의 건천화, 수질악화, 농업피해 등이 발생하고 있다. 무강우일수의 증가로 인한 피해는 농업지역에만 국한되지 않는다. 도시지역에 무강우가 지속될 경우 공기 중의 미세먼지가 효과적으로 제거되지 못하는 문제가 발생한다. 미세먼지로 인한 환경문제는 특정 배출지역에 국한되지 않고 기상조건에 따라 오염물질이 이동할 수 있으므로 타지역 및 타국가와의 갈등을 유발할 수 있다. 따라서, 정확한 분석을통해 원인을 규명하고 해결방안을 강구하는 것은 중요한 일이다. 이를 위해 본 연구에서는 먼저 한국환경공단에서 운영 중인 523개의 도시대기 측정소에서 관측된 PM₁₀ 시단위 자료를 이용하여 미세먼지의 추세를 분석하였다. 다음으로 미세먼지의 이동과 소멸과 연관성이 있을 것으로 판단되는 강우량, 습도, 풍속 등의 기상요소 및 무강우일수와 미세먼지 농도의 관련성을 분석하였다. 무강우일수는 전국에 분포된 103개 지상관측소의 시단위 강우자료를 통해 계산하였으며, 무강우일수와 미세먼지 농도의 관계는 각각의 무강우일수에 대응되는 미세먼지의 농도분포를 통해 년단위 및 월단위로 지역별로 분석하였다.

• Korean Journal of Agricultural and Forest Meteorology
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• v.17 no.3
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• pp.207-216
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• 2015

The study was conducted to determine the effects of forest restoration methods and stand structure on solar radiation, air temperature, relative humidity, soil temperature, and soil water content, based on volume, in forest stand after forest fire. The changes of the micro-climate elements in naturally and artificially restored forest after forest fire were measured in Goseong and Samcheok, Gangwon province. Pinus spp. were commonly appeared in ridges, barren lands or planted areas of the study sites while the other areas were dominated by Quercus spp. In the early stage, trees in the naturally regenerated site grow better than the trees in artificially rehabilitated site. However, the growth ratio rapidly decreased by time passed in natural regeneration area. The environmental conditions (solar radiation, air temperature, relative humidity, soil temperature and soil water content) were significantly different by the regions and the methods (p<.05). However, the coefficients of variations of the environmental conditions were not significantly different at 95% confidence level. As the coverage and tree height in crown layer increased, the relative humidity and soil water content were increased while the temperature and solar radiation were decreased. Especially, the relative humidity, solar radiation, and soil water content were clearly affected by the tree height and coverage ratio ($R^2$ means from 0.628 to 0.924). Even though the data should have collected at least more than 5 years in meteorological analysis, the two year results show some clear relationship between forest structure and microclimate elements.

• Journal of the Korea Concrete Institute
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• v.15 no.4
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• pp.574-584
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• 2003

The most common deterioration cause of concrete structures in urban environment is carbonation. Recently, the $CO_2$ concentration and temperature at atmosphere is sharply increased with time due to global warming phenomena. In this study, the climate scenario IS92a, which was suggested by the IPCC, is used to consider temperature and atmospheric $CO_2$ concentration change in the model of service life prediction. The modified mathematical solution, which was based on the Fick's 1st law of diffusion, was used to reflect concrete materials properties such as the degree of hydration of concrete with elapsed time, and important parameters, which associated with deterioration rate. The techniques of service life prediction are developed introducing the method of reliability and stochastic concept to consider microclimatic condition in Seoul, South Korea. From the result of service life prediction, concrete containing high W/C ratio is shown fast carbonation rate due to $CO_2$ concentration increase. It is concluded that the deterioration of concrete structures due to carbonation is insignificant problem on the conditions that below W/C 55%, well curing concrete.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2001.05a
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• pp.194-199
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• 2001

쾌적한 스포츠웨어는 기능성에 있어서 자연환경의 변화조건과 인체의 운동 및 활동에 맞추어 열절달 및 수분전달 등을 적절히 조절할 수 있어야 한다. 이에 본 연구에서는 일반환경조건 및 강우환경조건하에서의 형상기억 투습방수직물 소재의 스포츠웨어 착용에 따른 인체생리반응 및 쾌적감을 규명하기 위하여 스포츠웨어를 제작하여, 인공기후실에서 환경조건변화에 따른 온열생리학적 특성 및 주관적 감각을 측정, 그 특성을 비교, 고찰하였다. 평균피부온은 강우환경조건에서 온도가 낮게, 변동폭이 많게 나타났다. 변화경향을 운동부하를 기점으로 온도의 상승이 나타났고, 운동 2단계에 가장 높은 온도를 나타냈으며, 이후 감소하였다. 직장온은 일반환경조건에 비해 강우환경조건에서 온도의 미세한 상승을 보였다. 의복내 기후는 두 조건 모두에서 가슴부위보다 등부위의 온·습도의 변동폭이 크게 나타났고, 강우환경조건에서의 의복내 온도를 제외하고는 모두 등부위의 온·습도가 높게 나타났다. 최고 혈압은 운동의 강도에 따라 비례하여 상승하고, 최저 혈압에는 큰 영향없이 나타났으며, 변화경향은 의복내 온도의 경향과 역으로 나타났다. 평균혈압은 일반환경조건에서 6.9mmHg 높게 나타났다. 심박수는 일반환경조건에서 4.4beats/min 높게 나타났다. 강우환경조건의 주관적 감각의 평가에서, 신체에 직접 가해지는 빗물 등으로 인해 불쾌감이 증가하였고, 운동 후에는 일반환경조건과 달리 냉감이 증가하였으며, 습윤감은 최고치에 달하였다.

• Korea Petroleum Association Journal
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• s.307
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• pp.20-23
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• 2018

2018년 1월 국내에서는 처음으로 환경부와 수도권 지자체를 중심으로 '미세먼지 비상저감조치(이하 비상조치)'가 시행되었다. 공교롭게도 지방선거를 5개월 앞둔 시점에 비상조치가 시행되면서 언론 등을 통해 논란이 증폭된 점을 부인할 수는 없지만, 비상조치에 대한 뜨거운 논쟁은 최근 수년간 미세먼지 문제에 대한 시민들의 인식과 불편함이 상당히 높아져 왔음을 보여주는 사례이다. 일정 조건을 충족하면 비상조치가 언제라도 다시 시행될 수 있다는 점에서, 빠른 시일 안에 지난 1월의 경험을 돌아보고 우리 사회가 나아가야 할 방향을 재정립할 필요가 있다. 정책을 수립하고 시행하는 과정에서 경험한 바를 점검하고, 이를 통해 얻은 교훈을 바탕으로 앞으로 나아갈 방향을 다시 정립하는 과정(경험을 통한 학습과 환류)은 공공정책을 수립하고 시행하는 데 있어서 필수적인 요소이다. 이 글에서는 미세먼지 농도 기여율 연구 결과, 비상조치 경험, 기후변화 대응 과정의 교훈 등을 돌아보면서 목표관리 측면, 국제협력, 시민과 기업의 참여, 배출관리 부문, 노출저감 전략 등을 중심으로 앞으로의 미세먼지 대응 방향을 제안하고자 한다.

• The Korean Journal of Quaternary Research
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• v.14 no.2
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• pp.101-107
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• 2000

Using the phytogram system, this study monitored hourly environmental factors(climate and soil), and radial growths and cambium activities of conifers in Worak mountain for 28 months from May 1996 to October 1998 to examine the influences of climatic factors on tree growths/carnbium activities of conifers in Worak Mountain, Korea. The phytogram system first puts a fine electrode into cambial zone. This device can automatically record environmental factors and cambium electrochemistry(hydration and proton levels). Dendrometers are attached to the phytogram for monitoring seasonal dynamics of cambial growth. We compared the results of radial growth by species and by diameter class. The growth decreased in order of Larix leptolepis, Pinus densiflora and Pinus rigida. Pre-monsoon growths were fast and May-June moisture regime was the most critical for all species. In the middle of September, radial growths were finished. The proton level and stem diameter reached the minimum at 4 p.m. On the other hand, the hydration level reached the maximum at 4 p.m. This diurnal change resulted from transpiration and the release of water from phloem storage to sapwood through xylem stream.

• Korean Chemical Engineering Research
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• v.59 no.1
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• pp.127-137
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• 2021

Air emission charge for nitrogen oxide as a precursor of fine dust has been introduced and implemented within the country from 2020. Therefore, the development of economical combustion technology for NOx reduction has got more needed urgently. This study investigated the air-staging effect as a way to reduce the NOx during combustion of domestic unused forest biomass, recently possible to secure REC (Renewable Energy Certification) as a substitute for overseas wood pellets in a 0.1 MWth circulating fluidized bed combustion test-rig. Operating conditions were comparison with and without air-staging, the supply position of tertiary air (6.4 m, 8.1 m, 9.4 m in the combustor) and variation of air-staging ratio (Primary air:Secondary air:Tertiary air=91%:9%:0%, 82%:9%:9%, 73%:9%:18%). NO and CO concentrations in flue gas, profiles of temperature and pressure at the height of the combustion, unburned carbon in sampled fly ash and combustion efficiency on operating conditions were evaluated. As notable results, NO concentration with air-staging application under tertiary air supply at 9.4 m in the combustor reduced 100.7 ppm compared to 148.8 ppm without air-staging while, CO concentration increased from 52.2 ppm without air-staging to 99.8 ppm with air-staging. However, among air-staging runs, when tertiary air supply amount at 6.4 m in the combustor increased by air-staging ratio (Primary air:Secondary air:Tertiary air=73%:9%:18%), NO and CO concentrations decreased the lowest 90.8 ppm and 66.1 ppm, respectively. Furthermore, combustion efficiency at this condition was improved to 99.3%, higher than that (98.3%) of run without air-staging.