• 응용통계연구
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• 제24권3호
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• pp.535-546
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• 2011

본 연구는 겨울철 남한지역 황사출현일수에 대한 이 범주 계절예측모형 개발을 목적으로 수행되었다. 최근 31년간 관측된 황사출현일수를 예측량으로 하고, 황사발원지 기상요소(지상기온, 강수량, 강설량, 지상풍속)에 대한 NCEP 재분석자료 예측치와 광역규모 기후지수들을 잠재적 예측인자로 사용하였다. 월별로 구분하여 예측모형을 개발하기 위하여 네 종류 통계모형(중회귀모형, 로지스틱 회귀모형, 의사결정나무모형, 지지벡터기계)을 각각 적용하였다. 예측모형 평가측도인 정분류율, 탐지확률, 잘못된 경고를 사용하여 모형 비교하고 예측모형을 제안하였다.

• 한국환경과학회지
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• 제16권5호
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• pp.533-539
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• 2007

The research was conducted to simulate and interpret the change of $PM_{10}$ profile by Asian dust using the CALPUFF modeling system for the period April 6 through 18, 2001. The results, which are represented a daily variation of $PM_{10}$ concentration before and after Asian dust, was located between a minimum concentration of $50{\mu}g/m^3$ and a maximum concentration of $100{\mu}g/m^3$, Most concentration peaks in the $PM_{10}$ profile were shown within a level below 500 m and had a pattern that rapidly increased up the peak and decreased after the peak to 1000 m. Even though the shapes of the vertical profile during Asian dust days were similar to non-Asian dust days, no rapid change vertically was observed. In particular, the vertical profile on 1200 LST and 1800 LST was noticeably shifted to the higher concentrations, which means $PM_{10}$ in the atmosphere was changed into a vertically and horizontally heterogeneous form under the Asian dust event. Finally, it is con-firmed that the simulation result from CALPUFF might schematically sketched atmospheric $PM_{10}$ profiles and their change by Asian dust throughout the comparison with profiles of aerosol extinction coefficients, which were acquired from Lidar measurement at KGAWO.

• 한국환경보건학회지
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• 제43권2호
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• pp.122-129
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• 2017

Objectives: Most of the $PM_{10}$ in subway stations is spread by the train-induced wind from the tunnels. Therefore, in order to improve air quality in subway stations, it is important to remove the $PM_{10}$ from the tunnels. After the installation of PSD (platform screen doors), the influence of train-induced wind and $PM_{10}$ at the platform has decreased, but is estimated to have increased in subway tunnels. This study was conducted to investigate the control of $PM_{10}$ in subway tunnels by applying a 500-fold diluted solution mixed with a humectant using a natural polymer. Methods: For this purpose, we tested the dust reduction effect in a laboratory and corrosion test and water pollution using fish and aquatic plants for the natural dust collecting agent. In the tunnel of a subway station, we used the natural dust collecting agent over 15 days. The study was carried out on $PM_{10}$ control during operation, which accounts for more than 70% of subway dust. Results: As results, the natural dust collecting agent exhibited an excellent dust control effect, and it was safe for water quality and soil. It showed the effect of controlling $PM_{10}$ in the subway tunnel by 49.5- 64.7% over 15 days. The use of the dust collecting agent for the control of $PM_{10}$ could be confirmed in the subway. Conclusion: It is necessary to clearly explain the major portions of chemical components contained in $PM_{10}$ to figure out the characteristics of $PM_{10}$ and to develop effective reduction measures to decrease the adverse effects of $PM_{10}$ in the subway.

• 한국임상수의학회지
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• 제19권2호
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• pp.215-218
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• 2002

It is known that house dust mites which settle on sofa, carpet, and dust in the house ignite asthma and allergic rhinitis. Dermatophagoides farinae and Dermatophagoides pteronyssinus distribute widely and densely in Korea. In this study we carried out to identify that shed hair of dogs which was applied topically with fipronil ($\Frontline^{circledR}$) kill house dust mites. We co-cultured house dust mites with fipronil-applied hair of dog during 12 hours, and then compared the death rate of mites here with that cultured without hair. The larger amount of hair, the more mites were killed. The death rate of mites was higher than control significantly until 2 weeks after $\Frontline^{circledR}$ application. Hair which had been shed at 3 days after $\Frontline^{circledR}$ application always killed the smaller number of mites than not shed. The present study suggested that the use of $\Frontline^{circledR}$ to our pets control house dust mites effectively.

• 한국산업융합학회 논문집
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• 제20권4호
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• pp.339-343
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• 2017

Masks are a portable functional product for daily use. They can protect user health by filtering harmful fine particles in the air. In the past decade, there have been approximately 10 yellow dust incidences per year, amounting to a total duration of 20 days, and they continue to increase year after year. In addition, the frequency of yellow dust incidences in Korea has increased by more than four times compared to levels from the 1970s. Statistical reports indicate that annual damages caused by yellow dust amount to more than six trillion KRW. This study developed a zero-fog multi-layer mask with a collection efficiency and yellow dust and particulate matter filtration areas that are at least thrice as effective as existing masks. The new mask also reduces pressure drag by half.

• 화약ㆍ발파
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• 제17권2호
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• pp.45-51
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• 1999

본 연구에서는 Dust Fall Sample을 설치하여 한라시멘트 옥계 채광현장의 천공, 발파작업시 발생되는 분진을 측정하고, 실험적인 방법으로 100m길이의 가설 풍동을 만들어 풍속별 비산거리 및 분진입도 분포 등을 파악하여 주변작업 환경영향을 평가하였다. 그 결과 낙진량은 기본적으로 분진원으로부터 거리가 멀어질 수록 현저하게 감소하며, 같은 조건일 때는 풍속이 빠를수록 낙진량도 증가하였다. 또한 석회석 노천채광시 발파작업장으로부터 100m 내외의 주변 지표상의 낙진량은 아주 작은량임을 알 수 있었다.

• Advances in concrete construction
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• 제5권4호
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• pp.391-405
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• 2017

Cement acts as the most important component of concrete as it binds and holds the concrete together. But it is one of the major $CO_2$ emitters all over the world, during manufacturing (900 kg of $CO_2$ per 1000 kg). Some of the modern construction methods aim at reducing the amount of usage of cement and came out with numerous solutions for replacement of the same. One such supplement in current trend is the Steel dust or the Electric Arc Furnace Dust (EAFD), which is a waste product from the electric arc furnace when the scrap metal is melted. When the concrete containing steel dust is exposed to atmosphere, the environmental oxygen and moisture play role to form rust and ultimately the member becomes harder. As Cement is the binder of conventional concrete, only certain percentage of the same could be replaced by the new material, steel dust. Tests were conducted for the 28 days cube strength of M45 grade (suitable for prestressing) concrete which has 0%, 10%, 20%, 30%, 40% and 50% steel dust instead cement. From the test, the optimum percentage replacement of steel dust was obtained, for which the beams and overhead poles were cast, prestressed and tested for the failure load and deflections. A conventional concrete beam and overhead pole were also cast, prestressed and tested to compare the results with those of the beam and pole that contained steel dust. The load vs. deflection plot and other results from the test is also discussed.

• 한국토양비료학회지
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• 제49권6호
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• pp.760-767
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• 2016

Food waste (FW) has been recognized as a critical problem in Korea and many research was conducted to efficiently utilize or treat FW. Main purpose of this research was to evaluate a feasibility for producing fermented organic fertilizer with vegetable waste (VW). Three different organic materials (saw dust, coco peat, and waste mushroom media) were mixed with VW at the rate of 30, 40, 50% respectively. Total days of composting experiment were 35 days and each sub samples were collected at every 5 days from starting of composting. Result showed that inner temperature of composting was increased to $60{\pm}4^{\circ}C$ within 5~10 days depending on varied organic materials and mixing ratio. Among different treatment, the highest increase of inner temperature was observed when 30% of saw dust was mixed with VW. After finishing composting experiment, maturity of each compost was evaluated with solvita and germination test. Maturity index (MI) of each treatment was ranged between 5~7 indicating that manufactured fertilizer was curing or finished stage. Calculated germination index (GI) was at the range of 57.83~101.16 depending on organic materials and mixing ratio. Both MI and GI showed that manufactured fertilizer was met for fertilizer criteria while control (VW only) was not adequate for composting. Overall, VW can be utilized for making organic fertilizer mixing with saw dust, coco peat and more research should be conducted to make high quality of organic fertilizer with vegetable waste.

• 대한공간정보학회지
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• 제24권2호
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• pp.55-62
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• 2016

Economic and social damages are expected due to yellow dust, occurring every year in Korea and risk of citizens is getting higher accordingly. This study acquired tweet data for yellow dust, which had been the greatest since 2009 for 11 days before and after February 23, 2015. After that, it conducted an analysis on the issue words and association rule. Regarding acquired tweet data, the results of analyzing issue words by using open source R, statistics language shows that 'Mask' was ranked to be the highest, followed by health-related issue words. This indicates that people put the priority in the use of mask for keeping their health, as a result of the occurrence of yellow dust, and subsequently, they showed an interest in diseases, caused by yellow dust. In addition, yellow dust-related diseases, 'cold', 'rhinitis', 'flu', 'asthma', 'bronchitis' were found as issue words, revealing that people had a high concern on the disease occurrence of the respiratory system. The analytical results are judged to reflect the citizen's thought effectively in the process of establishing measures for the prevention of yellow dust.

• 한국대기환경학회지
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• 제32권1호
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• pp.67-81
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• 2016

In order to examine the variation characteristics of chemical compositions in accordance with the different meteorological conditions, $PM_{10}$ and $PM_{2.5}$ were collected at Gosan site of Jeju Island in 2014, and then their ionic and elemental species were analyzed. The concentrations of nss-$SO{_4}^{2-}$ and $NH_4{^+}$ were respectively 4.3 and 3.3 times higher in fine particle mode ($PM_{2.5}$) compared to coarse particle mode ($PM_{10-2.5}$), however $NO_3{^-}$ concentration was 1.6 times higher in coarse mode compared to fine particle mode. During Asian dust days, the concentrations of nss-$Ca^{2+}$ and $NO_3{^-}$ increased highly as 7.7 and 4.5 times in coarse particle mode, and 3.0 and 4.9 times higher in fine particles, respectively. Especially, the concentrations of the crustal species (Al, Fe, Ca, K, Mn, Ba, Sr, etc.) indicated a noticeable increase during the Asian dust days. For the haze days, the concentrations of secondary pollutants increased 2.2~2.7 and 2.9~6.0 times in coarse and fine particles, respectively, and they were 0.8~1.1 and 1.8~2.4 times, respectively, during the mist days. The aerosols were acidified largely by sulfuric and nitric acids, and neutralized mainly by ammonia in fine particle mode during the haze days, but neutralized by calcium carbonate in coarse particle mode during the Asian dust days. The clustered back trajectory analysis showed that the concentrations of nss-$SO{_4}^{2-}$, $NO_3{^-}$, and $NH_4{^+}$ were relatively high when the inflow pathway of air mass was from the southern part of China.