• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.1178-1187
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• 2008

Quality assurance for embankment compaction is one of very important procedures to guarantee high quality construction. However, only sand replacement method (KS F2312) and static plate load test (KS F2310) which are conventional and tiresome methods are used to evaluate degree of compaction at construction fields. Recently, new types of devices such as the geogauge and the light falling weight deflectometer (LFWD), the soil impact hammer (CASPFOL) and dynamic cone penetration test etc. which are able to substitute for the conventional methods are begun to use to evaluate soil stiffness. In this study, a laboratory model test was performed to evaluate correlations among test results obtained from the new devices and to assess the potential use of them. All test results have correlations with relative density and water content. Especially, the coefficients of correlation between $E_G$ from the geogauge and $K_{30'}$ from the soil impact hammer and between $E_G$ from the geogauge and $E_{LFWD}$ from LFWD are more than 0.7 but those between the results from DCP and others are less than those between $E_{G{\cdot}}$ and $K_{30'}$ and $E_G$ and $E_{LFWD}$.

• 한국지반환경공학회 논문집
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• 제20권4호
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• pp.5-9
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• 2019

본 논문은 건설재료(암석, 콘크리트, 목재 등) 등의 압축강도를 비파괴적으로 산정하기 위하여 재료타격 시 발생하는 충격력에 대한 응답신호를 모두 측정하고 이를 누적한 전체 충격력 신호에너지의 이용성 및 가능성에 관해 기초연구를 수행하고 그 결과를 제시하는 것이다. 본 연구에서는 이를 위해서 충격 및 측정장치를 고안하였고 이를 이용하여 측정대상물을 회전 자유낙하에 의해 초기 타격토록하고 이후 반발작용에 의한 반복타격이 소멸될 때까지 발생할 수 있도록 하였다. 본 연구에서는 서로 다른 강도를 가지는 목재와 암석시편에 대하여 충격력실험을 실시하고 발생신호를 측정하였다. 시편별 산정된 전체 충격력 신호에너지는 직접압축강도시험을 통한 시편별 압축강도와 상호 비교하였다. 비교결과, 충격력 응답신호를 통해 산정된 전체 충격력 신호에너지는 시편의 직접압축강도와 직접적인 관계가 있다는 것을 확인하였으며, 이를 통해 다양한 건설재료의 압축강도는 재료타격 시 발생하는 충격력 응답신호로부터 산정된 전체 충격력 신호에너지를 이용하여 비파괴적으로 산정할 수 있음을 알 수 있었다.

• 소음진동
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• 제5권1호
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• pp.95-106
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• 1995

Flow-induced vibration in heat exchanger (or fuel rod) in nuclar power plant can cause dynamic interactions between tubes and tube supports resulting in fretting-wear. To increase the reliability and design life of heat exchanger components, design criteria that establish acceptable limits of vibration and minimize fretting wear are necessary. The fretting-wear rate is dependent upon material combination, contact configuration, environmental conditions and tube-to tube support dynamic interaction. It is demostrated that the fretting -wear rate correlates well with tube-to-support contact force or work rate. The tube-to-support dynamic interaction, which consists of dynamic contact forces and tube motion, is used to relate single-span wear data to real heat exchanger configurations consisting of multi-span tube bundles. This paper describes the test facility to measure tube-to-support dynamic impact force and reports its dynamic characteristics through the four impact tests - a force transduces independent and external impact tests, central ring inside impact test and additional cylinder impact test. Through the tests the impact parameter change dependent upon the material difference of impacting ball is studied, and the impact parameters of Force Transducer Assembly components are measured. And also the dynamic behavior of Force Transducer Assembly is analyzed. The force measurement technique herein is shown to provide a reasonable measure of dynamic contact forces.

• 환경영향평가
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• 제19권3호
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• pp.347-356
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• 2010

Forests are being seriously fragmented as a result of land development. Land development with disregard to its subsequent environmental impacts is a primary threat to biodiversity by incurring massive habitat losses and changes in structure and composition of forests. The purpose of this study was to develop the impact assessment model for quantitative distance or degree of disturbance by land developments. This study conducted a survey about structure and composition of forest species to determine degree of impact from land development. The edge effect of forest fragmentation on the number of bird species, population size, and bird diversity was obvious. In particular, the bird diversity sharply declines around the forest edge where intensive land development projects take place. To assess the disturbance of forest species, the factors selected were the bird diversity and the rate of edge species. The impact assessment model about bird diversity was explained by type of forest fragmentation and type of vegetation ($R^2$=0.23, p<0.005). The other model about edge species explained by a distance, type of forest fragmentation, type of vegetation, and width of road ($R^2$=0.34, p<0.001). In order to test the applicability of the model developed in this study, the models was applied to the Samsong housing development in Goyang-si, Gyunggi-do. The impacts of land development on the bird species were reasonably quantified to suggest effective mitigation measure. The impact assessment model developed in this study is useful to assess the magnitude of disturbance of bird species. Particularly, the model could be applied to the current Environmental Impact Assessment practices to predict and quantify the impacts of land developments projects on forest bird species.

• Journal of Welding and Joining
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• 제30권5호
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• pp.22-26
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• 2012

Butt-joints of A6061-T6 and AZ31 plates were successfully manufactured by using a friction stir welding method. Off-set free joints and off-set joints were fabricated to investigate the effect of the tool plunge position on the mechanical properties of the joints. Hardness test, tensile test and charpy impact test was performed to evaluate the mechanical properties of the joints. Off-set condition resulted in increase of mechanical properties of the joints. The variation of the hardness distribution in the SZ was also stabilized in the off-set condition. Tensile strength of the off-set joint was about 85% against to that of the AZ31 base metal. Impact absorption energy by Charpy-Impact-Test of the off-set joint also increased by almost 2 times against to that of the AZ31 base metal.

• 환경영향평가
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• 제33권2호
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• pp.64-73
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• 2024

개발사업으로 인한 서식지 파괴의 심각성이 대두되면서 생물다양성을 보전하기 위해 환경영향평가(EIA)의 중요성은 커지고 있다. 경관스케일에서 개발 요인과 주변 환경요인에 따른 생물다양성 영향을 정량적으로 평가하기 위해 선행연구들이 진행되고 있으나, 개발사업을 기준으로 생물다양성 감소에 영향을 미치는 요인에 대한 연구는 미흡한 실정이다. 본 연구는 선행연구를 통해 유효하다고 밝혀진 독립변수(사업 면적, 사업 유형, 고도, 생태·자연도, 녹지와의 이격거리, 보호구역과의 이격거리)들을 다중클래스 로지스틱 회귀분석, T-test, 사업 유형 검토분석을 통해 종풍부도 변화에 유의미한 영향을 미치는지를 검토하였다. 연구 결과, 토지 피복 단위에서 생물다양성에 영향을 끼치는 것으로 밝혀진 요인 중 사업 규모와 환경영향평가 시 종풍부도 값만이 p-value=0.05 이하의 값을 보였다. 그리고 사업 유형의 경우, 체육시설의 설치, 에너지 개발, 산업입지 및 산업단지의 조성에서 조류의 생물다양성 감소가 크게 변화하는 것을 확인하였다. 본 연구를 통해 분석 규모에 따라 영향을 끼치는 변수에서의 차이가 발생할 수 있음을 확인하였기에, 환경영향평가에서 생물다양성 변화를 분석하기 위해서는 개발사업 단위에서의 지표 활용에 연구가 추가로 필요할 것이며, 타 생물종으로의 일반화를 위해 추가적인 연구가 필요할 것으로 사료된다.

• 환경영향평가
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• 제5권2호
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• pp.21-31
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• 1996

To assess the impact resulted from the slag dumping, we studied that the changes in the concentration of heavy metal were researched through the statistic analysis at 4 stations in Yongil bay, Korea from 1988 to 1995. And in order to clarify resulting from the changes in heavy metal concentration due to be leaked out from dumped slag, it was fulfilled experiments of the slag extraction. In the extracting experiment, Pb and As were only leaked out from slag aged during 10 days but all of heavy metals were not from it aged during 90 or 180 days. It was found that the concentrations of heavy metals in sea water of vincinity of slag dumping area were still remained in similar, comparing with it of control site(site 4) when they were by analysed statistic method, anova test and Mann-Whitney test. The slag recycling ratio of our country is lower than foreign country. While we need to apply a new process for phosphate treatment, foreign country already apply a slag to phosphorous removal. We suggest that slag dumping cannot putatively affected the changes in the concentration of heavy metal. And we thought that impact of heavy metal induced by slag dumping was not severe. So, it is necessary to utilize this process in phosphorous removal, like a foreign country.

• 환경영향평가
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• 제20권1호
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• pp.37-48
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• 2011

Recently, the social and environmental functions of nature river are important due to the increase of expectation for river restoration. So it should be considered the effect of vegetation affecting the conveyance capacity and hydraulic resistance. However, it has not yet proposed a objective standard and modeling method to estimate the effect of conveyance capacity according to vegetaion distribution in the watercourse such as water level or velocity. Therefore, this study simulates the variations of water level and velocity using 3-dimensional hydrodynamic model, EFDC, to consider a conveyance capacity in downstream of the Soyang Reservoir. The simulation results were validated using statistical index such as F-test and T-test. As results, the water level rises about 0.01 to 0.47m and velocity difference are about -0.95m/s to 0.23m/s.

• 대한간호학회지
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• 제41권2호
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• pp.236-244
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• 2011

Purpose: In this study the impact of pro-environmental behavior, well-being oriented behavior, and use of cloth menstrual pads on dysmenorrhea in Korean female adults was examined according to the theory of reasoned action. Methods: A cross-sectional study was conducted with 195 Korean female adults. Data were collected from June to August, 2010 using self-report questionnaires. Data were analyzed using t-test, one-way ANOVA, Pearson correlation coefficients, multiple regression, and logit regression with STATA 10.0. Results: Pro-environmental behavior explained 48% of well-being oriented behavior. Well-being oriented behavior explained 10% of cloth pad use. Use of cloth pad explained 4% of dysmenorrhea and 5% of menstrual pain. The path through well-being oriented behavior had a significant effect from pro-environmental behavior to cloth pad use. Conclusion: Use of cloth pad was significantly related with well-being oriented behavior, pro-environmental behavior, social influence, dysmenorrhea, and menstrual pain. The results of this study suggest that pro-environmental strategies can help health care providers diminish clients' menstrual symptoms. Nursing intervention can support pro-environmental behavioral strategies.

• 환경영향평가
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• 제9권1호
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• pp.75-86
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• 2000

The purpose of this work was to document the conditions regarding organic solvent exposure to the workers in paint industry. Air concentrations of organic solvents were measured by passive personal samplers and analyzed by a gas chromatography. Urine samples for hippuric test were also taken from 330 workers who have worked at seven domestic factories for more than two years. Amongst 25 organic elements detected in the indoor environment of working places, toluene was the most common element, and methanol showed the highest mean concentration(18.2ppm). A few elements including methylethyl ketone and toluene partially exceeded the Korean Permissible Exposure Limit. A lack of environmental facilities such as exhaust ventilation, automatic cleaning system, and personal safety devices at present work plaus brings about various occupational diseases.