• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.1
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• pp.27-35
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• 2019

The existing middle-long span railway bridge has been mainly applied to steel box girder bridges. However, the steel box girder bridges have disadvantages in securing the space under the bridge, and the main girder is made of a thin plate box shape, resulting in a ringing noise due to the vibration. Many complaints about noise have been raised. For this reason, there is a need for the development of long railway bridges that can replace steel box girder bridges. In this paper, the characteristics of the steel composite railway bridge currently developed were introduced and a time history analysis was conducted using MIDAS Civil reflecting the speed of KTX load for 40m and 50m bridges. In addition, from the analysis results, the dynamic behavior of target bridges were verified and it was examined whether they meet the dynamic performance criteria proposed in the railway design standards. As a result, all of the bridges under review satisfied the dynamic safety criteria, however, in case of 40m of span, the vertical acceleration value was very large. In order to solve this problem, authors proposed the improvement plan and corrected the cross section to confirm that the vertical acceleration decreased.

• Korean Journal of Heritage: History & Science
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• v.52 no.1
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• pp.82-89
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• 2019

In this study observation records of the National Natural Environment Survey (2008-2012, 2014-2017) and the Korean Natural History Research Information System (KNHRIS) for the common kestrel (2013-2016) were consulted to determine the correlation of the distribution of kestrels in an area and the area's land use type. Distribution characteristics were studied based on data collected over the last 10 years (2008-2017). Findings show that the common kestrel is widely distributed between 4,407 sites registered in KNHRIS in the period of 2008-2012, 3,899 sites in 2014-2017, and 508 sites in 2013-2016. Relationship analysis was conducted for the altitude and urban planning factors of statistics based on a 2017 GIS check to determine the distribution characteristics. The birds' altitude was confirmed to range from 0 to 1,200 metersck but was most commonly observed at less than 100 meters. Above 200 meters, the rate of occurrence decreased rapidly. The rate of occurrence of the common kestrel was highest in Chungcheongnam-do province, followed by Gyeongsangbuk-do, Kyonggi-do, Jeollanam-do and Jeollabuk-do. As urban areas, green areas, commercial areas, and industrial areas the presence of swere positively correlated with the presence of kestrels, the rate of occurrence of the kestrel was higher in those regions. However, there was no significant relationship between the incidence of kestrels and housing construction or residential areas.

• Journal of Food Hygiene and Safety
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• v.34 no.3
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• pp.263-268
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• 2019

Methanol is a toxic alcohol used in various products such as antifreeze, detergent, disinfectant and industrial solvent. In the human body, methanol is oxidized to formaldehyde and formic acid, which can lead to metabolic acidosis, optic nerve impairment, and death. In this study, the methanol levels in detergents (n=191) and rinse aids (n=13) were analyzed by gas chromatography-headspace-mass spectrometry (GC-HS-MS). Limit of detection was 1.09 mg/kg, accuracy and precision were 91.1-97.9% and <10%, and it was suitable for quantitative analysis. This analysis method was simple and fast with a higher recovery rate than the conventional MFDS (Ministry of Food and Drug Safety) method of diluting the sample in water and putting it in a headspace vial.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.7
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• pp.528-534
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• 2019

This study analyzes the factors affecting China's carbon emissions from 1985 to 2016. In recent years, the whole industries of China are in the midst of industrialization and have several problems. Now, the low-carbon economy has become the main task of China's economic development. This study analyzes the factors affecting China 's carbon emissions by selecting relevant data onto the Chinese yearbook and using a time series model. The analysis shows that related industries continue to innovate and increase the use of green energy such as electricity, but coal is still the largest share of the energy consumed. As energy use efficiency increases and industrial R&D investment increases year by year, carbon emissions are increasing every year. In addition, there is a stereotype that industry is the biggest factor affecting carbon emissions. The research found that the impact of the industry on China's carbon emissions is declining gradually. While controlling industrial carbon emissions, keeping continue to improve technology development and focusing on carbon emissions from other industries are critical to reduce overall carbon emissions. Based on the empirical results, if we can change stereotypes starting from the nature of the data, we will quickly reach a low carbon sustainable development economy.

• Korean Chemical Engineering Research
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• v.57 no.3
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• pp.331-337
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• 2019

Titania has become the most applicable material for photocatalytic application. Nevertheless, titania has the weak point in its wide band gap energy that is mainly activated by UV irradiation. There have been vast research challenges in order to make the wide band gap energy of titania narrow that could be activated in the presence of visible light. Various modifications of titania surface were popular because titania needs to change its surface to respond in visible light. Among the methodological approaches, N-doping to titania can be the alternative candidate because it is facile process and eco-friendly. The activated electron from valence band in N-doped $TiO_2$ migrates to conduction band in the presence of visible light irradiation, which shows photocatalytic activity as well. In this study, focused on the evaluation of nitrogen state after N-doping through brief review. Arguments are still existed in nitrogen states and their different effects on photocatalytic activity. In particular, two nitrogen states are generally reported; substitutional and interstitial states. The research articles regarding N-doped $TiO_2$ are continuously appearing because the potential application of water split in visible light is still fascinate. The future of N-doped $TiO_2$ is also presented by referrals based on various literature.

• Journal of the Korea Institute of Building Construction
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• v.19 no.3
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• pp.263-272
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• 2019

Building Information Modeling (BIM) and modular construction are regarded as important technologies that have contributed to advancements in the construction industry. However, the utilization of BIM in current modular construction projects is limited; moreover, there are no specific guidelines pertaining the applications of BIM in modular construction projects. Therefore, this study aims to analyze the utilization of BIM for onsite construction planning in modular construction projects. First, a realistic BIM application was selected through literature review and expert interviews. Then, the construction plan of the modular projects was analyzed to classify the BIM application items into five different categories. The utilization of BIM in each category was then analyzed in terms of necessity and efficiency using a questionnaire. Finally, the BIM Utilization Index (BIM UI) was suggested based on the findings of the survey. As a results, the BIM UI for module point details, lifting plan, other installation details, site layout plan, and schedule plan was 0.811, 0.787, 0.770, 0.729, and 0.699, in the descending order of usability. In addition, through the findings of the study and interviews with experts, a case study for implementation of BIM in modular construction plan was conducted. The results of this study can be used as application guidelines for BIM in future modular construction projects.

• Journal of the Korea Convergence Society
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• v.12 no.4
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• pp.105-112
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• 2021

Unlike conventional online shopping malls that handle simple product sales, customization services have to be provided with a user-centered and smooth customizable work environment because of differences that buyers have to customize themselves. To study the ease of use of T-shirt customization web GUI, three websites that provide T-shirt customization services were selected to analyze the current status of T-shirt customization websites. Through prior research, we establish the evaluation principle as consistency and clarity, operability, feedback, coping with errors, sharing and ease of search. Based on this, the T-shirt customization web GUI design guidelines were drafted and three delphi surveys were conducted on GUI-related experts to prove the validity of the web GUI guidelines evaluation items that are effective in customizing T-shirts. This study is expected to contribute to increasing the production and usability of the T-shirt customization web and to be used as an effective reference for customization web GUI design.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.254-254
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• 2017

수자원장기종합계획은 수자원의 안정적인 확보와 효율적인 이용 개발 및 보전을 위하여 "하천법" 제23조에 근거하여 수립되는 물 분야의 최상위 법정계획이다. 수자원장기종합계획은 20년 단위로 수립되며, 5년마다 그 타당성 여부를 검토하여 필요한 경우에는 계획을 변경하고 있다. 국토교통부는 지난 2016년 12월 수자원장기종합계획 제3차 수정계획(2016~2020년)을 수립 고시하였다. 그런데 수자원장기종합계획과 같이 상위 개념의 법정계획의 수립을 위해서는 관련 법정계획 및 부처 간의 수평적 수직적 연계가 중요한데, 현행 법체계는 이에 미흡한 측면이 있어 보인다. 우선적으로 수평적 연계를 위해서는 수자원장기종합계획 수립과정에 이수 치수 및 방재 분야의 업무를 담당하고 있는 관련 부처의 적극적인 참여를 독려할 필요가 있다. 현재 "하천법" 제23조제4항은 수자원장기종합계획을 수립하거나 변경할 경우, 중앙행정기관의 장과 협의하도록 규정하고 있다. 그러나 현행 규정에 따른 부처별 '협의'는 국토교통부가 수자원장기종합계획을 수립한 후 관련 부처의 의견을 수렴하는 소극적 형태의 협의라고 볼 수 있다. 효율적인 수자원장기종합계획 수립을 위해서는 "하천법" 소관 부처인 국토교통부가 수자원장기종합계획 수립을 위한 기본적인 지침을 수립하여 관련 중앙부처인 환경부(환경), 국민안전처(치수), 산업통상자원부(공업용수) 및 농림축산식품부(농업용수)에 시달하고, 각 부처는 담당 분야별 계획을 수립하여 국토교통부에 송달한 후, 국토교통부는 이를 취합 검토하여 수자원장기종합계획을 수립하는 적극적 형태의 연계를 고려할 필요가 있다. 수직적 연계를 위해서는 기존의 하향식(top-down)에서 벗어나 상향식(bottom-up)의 계획수립이 필요해 보인다. 즉 국토교통부의 수자원장기종합계획 수립에 따라 하위 개념의 유역종합치수계획("하천법" 제24조) 및 댐건설장기계획("댐건설 및 주변지역지원 등에 관한 법률" 제4조) 등을 수립하는 것이 아니라, 지역별 유역별로 수자원계획을 우선적으로 마련하도록 하고 이를 기초로 전 국토를 대상으로 하는 수자원장기종합계획을 수립하는 방안이 적절해 보인다. 이를 위해서는 수자원장기종합계획 수립하기 이전에 지역별 또는 유역별로 수자원계획을 수립할 수 있도록 "하천법"에 관련 규정을 신설할 필요가 있으며, 이수뿐만 아니라 환경, 방재 분야의 하위 법정계획의 수립 시기 및 주요 내용에 대한 종합적인 검토가 요구된다.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.245-245
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• 2016

지난 해 금강수계 강수량은 835.0mm로 평년('81~'10)의 64.3%, 삽교천수계는 765.1mm로 평년의 61.1% 정도로 매우 적었다. 특히 작년 6월부터 9월까지의 금강수계 강수량은 343.1mm로 평년 894.8mm의 38.3%, 삽교천수계 강수량은 301.1mm로 평년 860.6mm의 35.0% 수준으로 일반적으로 연간 강수량의 2/3가 여름철에 집중되는 현상과는 매우 다른 양상을 보이며 충남 서북부지역 8개 시 군은 최악의 가뭄을 겪었다. 따라서 작년 가을에는 전국적으로 가뭄이 만연한 가운데에서도 충남 서북부 8개 시 군에는 8월말부터 시작된 물 절약 캠페인에 이어서 10월8일부터 물 사용량 20%를 줄이기 위한 급수조정이 시작돼 지역주민들의 일상생활이 제약을 받기 시작하였다. 수도꼭지를 틀어보아도 시원한 물줄기를 볼 수 있은 지가 오래되었고 목욕이나 세차 등으로 충분히 물 쓰는 것이 눈치가 보일뿐더러 마실 물 걱정까지 해야 하는 상황이었다. 그리고, 금강수계 대부분의 생활용수 및 공업용수 공급을 담당하는 대청댐의 상황도 2015년 9월말 기준 누적 강수량은 536.7mm로 전년 강수량 791.6mm 대비 67.8%, 예년 강수량 1,077.5mm의 대비 49.8% 수준으로 강수량이 매우 적은 상황이었다. 9월말 기준으로 대청댐의 '15년 누적 강수량은 1981년 댐 운영 이후 가장 최소이며, 2순위로 9월말 누적 강수량이 적었던 해는 1994년이며 이 때 누적 강수량은 543.8mm, 3순위로 적었던 해는 1982년으로 이 해는 585.8mm였다. 대청댐의 저수위 현황을 살펴보면 6월말에 예년 수준과 비슷한 수위로 운영하였지만 7월말부터 예년보다 수위가 낮아지기 시작하여 8월 이후에는 예년과 격차가 나기 시작하였고 작년 10월 중순에는 1981년 댐 운영 이후 3번째로 낮은 저수율을 보이고 있는 상황이었다. 따라서, 이러한 상황에 대처하기 위해 6월부터 실수요량 수준으로 용수를 공급하기 시작하였고 8월말부터 농업용수 공급량 중 일부를 감량하였고 10월부터는 생공용수만 하루 1,987,200톤으로 계획하여 공급하면서 '16년 우기 전까지 최대한 저수량을 확보하면서 용수공급을 지속할 수 있도록 운영하였다. 본 연구에서는 '15년 강수량 부족으로 상당한 어려움을 겪은 충남지역을 중심으로 가뭄 현황을 분석하고, 충남 서북부지역의 주요 공급원인 보령댐과 기타 충남지역의 주수원인 대청댐의 운영현황과 가뭄상황을 타개하기 위해 추진한 방안 등을 살펴보고자 한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.638-643
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• 2021

Oil is used in various industries, including the agricultural sector, food industry, and functional cosmetics. These oils are chemically unstable and prone to oxidation when exposed to oxygen, light, moisture, or high temperatures. Therefore, various attempts have been made to encapsulate them so that they are not exposed to such environments. When oil is injected into a refrigerant with greater density, the oil can be encapsulated as it rises due to buoyancy caused by the density difference. In this study, oil encapsulation was simulated to find the optimal conditions for operating equipment using computational fluid dynamics (CFD) for multiphase flows. Water or serum can be used as a refrigerant. The viscosity of water is relatively small, and if it is used as a refrigerant, oil droplets can be produced well even if oil and water are continuously injected in the equipment. However, the viscosity of serum is very high, and if it is used, the oil is stretched out and does not leave the nozzle. The results show that when using serum as a cooling medium, oil encapsulation is possible if the injection is stopped for some time after instantaneous injection at high speed.