• 방사성폐기물학회지
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• 제16권1호
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• pp.41-47
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• 2018

원전사고 및 시설보수 과정에서 방출되는 방사성물질 중 $^{137}Cs$은 토양의 주 오염원 중 하나이다. 세슘으로 인한 토양오염은 주민의 거주 및 공업용지로의 재사용을 위해 제염이 불가피하다. 본 연구에서는 다양한 토양복원 기술 중 국내 외에서 실제 방사성물질로 오염된 토양에 적용한 사례가 있는 토양세척 기술을 선정하였다. 토양세척 공정은 세척제를 사용하여 토양과 세슘의 표면장력을 약화시켜 토양과 세슘을 분리하는 원리이다. 이러한 토양세척 공정의 세척수 재사용을 통해 공정효율을 높이고자 세척수에 응집제를 적용하여 미세토양 및 세슘의 제거 성능 실험을 수행하였다. ICP-OES를 통해 세슘 수용액에 토양을 첨가하여 세슘을 흡착시킨 후 응집제를 첨가하여 세슘의 농도를 측정하였으며 응집제 적용시 최대 세슘 제거율은 약 88%, 최소는 67%였다. Visual MINTEQ Code를 통한 세슘과 토양과의 종결합을 예측하였으며 탁도 측정을 통해 응집제 투여 후 탁도를 측정하여 세척수의 재사용 여부 및 미세토양 제거율을 분석하였다.

• 대한기계학회논문집A
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• 제34권11호
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• pp.1779-1784
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• 2010

어업 분야에서 그물세척 작업은 엄청난 노동력과 작업시간을 요구하며 심한 환경 오염을 발생시킨다. 본 연구에서는 그물 양망 기능과 세척 기능, 그물펴짐 기능을 동시에 갖춘 그물세척용 양망기를 개발하였다. 양망회전체의 구조를 개선하여 구조물의 안정성을 높이고 대형 그물의 양망 중에 발생할 수 있는 그물 슬립 문제를 해결하였다. 양망기에 세척 기능을 부가하여 그물자동세척기를 이용한 최종 세척 전 단계에서 1 차 세척을 수행하거나 중소형 그물의 주 세척 작업에 세척용 양망기를 사용할 수 있도록 하였다. 대형 그물 세척을 위한 그물자동세척기의 세척 효율을 높이기 위하여 양망기 하단에 그물펴짐보조대를 설치함으로써 양망기로부터 접힌 채내려오는 그물을 펴는 작업이 용이하도록 양망기를 설계하였다. 시작품을 제작하여 그물 세척 실험을 수행한 결과, 양망 중에 그물슬립을 완벽히 방지할 수 있었고 양망기의 1 차 세척 기능에 의하여 그물 펴는 작업의 수월함을 확보함으로써 작업 효율과 세척 효율을 대폭 향상시킬 수 있었다.

• Tribology and Lubricants
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• 제31권3호
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• pp.102-108
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• 2015

In this research, we experimentally investigated the sealing performance of elastomeric rotary lip seals for washing machines. In general, NBR is used as a material for elastomeric rotary lip seals in washing machines, but the mixing formula of the rubber material can affect the sealing performance. In this study, we manufactured rotary lip seals using three kinds of NBRs with a different mixing formula, and examined the sealing performance using an acceleration test mode. The results of an SEM investigation into the surfaces of three kinds of specimens showed a much smaller wear volume and better sealing performance for the specimens with smaller particle sizes of mixing composition than for the specimen with the larger. Repeated deformation and recovery by the shaft-to-seal eccentricity on rotation were shown to cause a phase difference in the rubber material, and we measured the recovery ratio to find the influence of this phase difference on the sealing performance. As another method for checking the phase difference, we also measured tan ä, and a lower tan ä was revealed as the recovery ratio increased for each specimen. Specimens with a higher recovery ratio (lower tan ä) were shown to have a better sealing performance. Consequently, specimens with a smaller particle size in the mixing composition had a better sealing performance because they show a higher recovery ratio.

• 한국응급구조학회지
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• 제20권2호
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• pp.21-35
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• 2016

Purpose: This study aims to investigate awareness and performance of infection control during ambulance attendant training, and to provide basic data for infection control. Methods: The subjects were 235 paramedic students who completed ambulance attendant training. There were 51 questions. The infection control dimension was divided into hand washing, personal protective equipment use, and environmental management, for each sub-dimension, awareness and performance were measured by a 4-point scale. The collected data were analyzed using SPSS statistics ver. 22.0. Results: A total of 95.3%, of the subjects completed an orientation for ambulance attendant training and 71.7% received education on infection. In all three sub-dimensions, hand- washing (p<.001), personal protective equipment use (p<.001), and environmental management (p<.001), awareness scored higher than performance. The awareness of infection control showed a significantly positive correlation (r=.394) with performance. Conclusion: In order to improve performance of infection control, education to improve awareness should be provided, and paramedics with higher performance levels in hand washing, and use of gloves and masks wearing should be assigned as training advisors.

• 한국소음진동공학회논문집
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• 제24권2호
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• pp.117-122
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• 2014

A novel method to reduce the vibration of drum type washing machine is proposed. Recently, as the capacity of the drum-type washing machine gets expanded and its washing performance is improved, its market share is increasing in the whole world. But, the capacity of washing machine is limited because of door size and built-in washing machine size. The vibration of washing machine is caused by unbalanced cloths in high spining drum, and the displacement of tub is maximized at transient range about 3 Hz(180 rpm). Previous researches were concerned about steady-state vibration in spinning. In this study, concerned about transient vibration and the displacement of tub is decreased by using gyroscope system. Mutibody dynamic model of washing machine include gyroscope is designed and the vibration of tub have been reduced by 44.7 % over original.

• 대한영양사협회학술지
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• 제15권3호
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• pp.220-231
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• 2009

The principal objective of this study was to evaluate elementary students' awareness of the importance of hand washing, as well as their hand-washing behavior. The data was collected by self-reported questionnaire from 697 students in elementary schools with serving food in a classroom in Busan. Their hand-washing frequency was high, at '3~4 times per day (37.0%)'. 51.0% of the respondents did not wash their hands that often because they were 'not accustomed' to washing their hands, and 35.9% of respondents regarded washing their hands as 'annoying'. The most frequently reported hand washing agent was 'soap and water (71.4%)'. Approximately 95~98% of the respondents always washed their hands after using the bathroom, 87.9% of them washed their hands before eating food, and 86.7% of them washed their hands upon returning home. However, 27.3%, 34.1% and 65.9% of the respondents did not wash their hands after handling money, after eating, and after coughing or sneezing, respectively. Significant factors related to increased hand-washing frequency were gender (p<0.001) and the period of attendance at kindergarten (p<0.05). The mean scores of importance and performance of hand washing were significantly higher for girls than for boys. The group with higher rate (over 4.5/5.0) for the importance of sanitary hand-washing behavior showed significantly higher scores in hand-washing behavior before serving food and before eating than those of the lower rated group (below 4.0/5.0). This study shows that sanitation education is required not only for food handlers but also for students in school foodservices.

• Membrane and Water Treatment
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• 제9권3호
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• pp.137-146
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• 2018

Soil washing is one of the most frequently used remediation technologies for heavy metal-contaminated soils. Inorganic and organic acids and chelating agents that can enhance the removal of heavy metals from contaminated soils have been employed as soil washing agents. However, the toxicity, low removal efficiency and high cost of these chemicals limit their use. Given that humic substance (HS) can effectively chelate heavy metals, the development of an eco-friendly, performance-efficient and cost-effective soil washing agent using a nano-scale chelator composed of HS was examined in this study. Copper (Cu) and lead (Pb) were selected as target heavy metals. In soil washing experiments, HS concentration, pH, soil:washing solution ratio and extraction time were evaluated with regard to washing efficiency and the chelation effect. The highest removal rates by soil washing (69% for Cu and 56% for Pb) were achieved at an HS concentration of 1,000 mg/L and soil:washing solution ratio of 1:25. Washing with HS was found to be effective when the pH value was higher than 8, which can be attributed to the increased chelation effect between HS and heavy metals at the high pH range. In contrast, the washing efficiency decreased markedly in the low pH range due to HS precipitation. The chelation capacities for Cu and Pb in the aqueous phase were determined to be 0.547mmol-Cu/g-HS and 0.192mmol-Pb/g-HS, respectively.

• 한국지하수토양환경학회지:지하수토양환경
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• 제19권6호
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• pp.72-79
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• 2014

Cavitation generated by ultrasonic irradiation can enhance the diffusional transport of organic contaminants from soil surfaces or pores. Therefore, ultrasound soil washing can be an alternative of traditional soil washing process. In this study, soil was artificially contaminated with n-tetradecane, n-hexadecane and phenanthrene. A plate type ultrasonic reactor at 25 kHz frequency and 1000W power was used for laboratory soil washing experiments. Ultrasonic soil washing efficiency was compared with those of traditional soil washing using mechanical mixing. Various operational parameter such as soil/liquid ratio, irradiation time, particle size, and soil organic matter content was tested to find out the optimum condition. It was found that ultrasonic soil washing demonstrates better performance than mechanical soil washing. Optimum soil:liquid ratio for ultrasonic soil washing was 1 : 5. Desorption of organic contaminants from soils by ultrasonic irradiation was relatively fast and reached equilibrium within 10 minute. However, decrease in the soil particle sizes by ultrasonic irradiation results in re-adsorption of contaminants to soil phase. It was also observed that soil particle size distribution and soil organic matter content have significant effects on the efficiency of ultrasonic soil washing.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1849-1852
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• 2005

An automatic cap-washing machine is developed for rinse and dry of synthetic resin cap which is used in spring water bottle. This machine should be achieved all processes washing and drying, array, transfer automatically. A cap is washed by an ozonized water and pure water first. Next, a cap is dried by a hot wind drying equipment. In this paper, structural and modal analysis for the cap-washing machine is carried out to check the design criterion of the machine. The analysis is carried out by FEM simulation using the commercial software, CATIA V5. And a fictitious mass properties was used for the analysis of the machine. Finally, the machine performance is shown to be satisfactory.

• Journal of Biosystems Engineering
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• 제36권5호
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• pp.361-368
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• 2011

The amount of export of paprika has been increased rapidly in recent years. Therefore, its cultivation area has greatly increased in Korea according to current consumer's attraction. Moreover, it becomes one of the major exporting products while it recorded 53 million dollars, in 2009 resulting in 40% of the total vegetables export. Most of the products are exported to Japan, but it is necessary to prolong the quality preservation periods to export paprika to nations like U.S.A. or EU. However, to encourage an export to many countries, washing and disinfection became more important to deal with longer transportation and medical inspection. The non-chemical use is very important due to stronger regulation of safety to agricultural production. Accordingly, this study was performed to determine the optimum conditions and develop a prototype washing machine, hot water washing of paprika. The results were as follows : The working performance of the prototype was 938 kg/hr, and which was 1.5 times higher than the conventional air gun type washing machine. The operation cost of prototype was 30 won/kg, and 56% of the cost was reduced when compared with air gun type washing machine.