• 한국전산구조공학회논문집
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• 제29권5호
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• pp.389-395
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• 2016

본 논문에서는 Co-Rotational plane beam transient analysis EDISON program(CR-보)를 이용한 에어포일 단면형상 변화에 따른 진동특성 연구를 수행하였다. Co-Rotational 평면 보 해석은 대 회전과 작은 변형률을 갖는 보 해석에 적합하다. 항공기의 날개를 외팔보로 가정하여, VABS를 통한 단면해석과 Fourier 변환을 통해 각 단면형상 변화에 따른 에어포일의 고유진동수를 비교하였다. VABS를 사용하여 단면의 형상과 재료의 적층 정보를 고려한 단면에서의 유한요소 해석을 수행하였다. 에어포일의 재질, spar 유무, 단일 등방성 재료 복합재료, 에어포일 최대두께의 변화에 따라 에어포일의 끝단 진폭과 고유진동수가 변화함을 확인할 수 있었다. 이를 바탕으로 에어포일 고유진동수 변화는 2차 관성모멘트/단면적, 밀도, 영률의 변화에 상당한 영향을 받음을 알 수 있었다.

• 한국조경학회지
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• 제32권5호
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• pp.43-51
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• 2004

Recently, the importance of choosing correct pavement materials has been increasing in urban spaces and streets. Much research regarding the pavement theory and construction method have been conducted, but analysis in terms of human psychological character has not yet been performed. The purpose of this study is to investigate the psychological characters to 12 pavement materials, that are commonly used in our urban spaces and streets. The results of the psychological character for each pavement material can be summarized as follows: 1. The psychological characters to each pavement material were as follows: ① Clay embodies a natural, traditional, soft and intimate psychological character; ② Pebble stone has a natural, hard, cool and intimate psychological character; ③ Turf grass incorporates an intimate and soft psychological character; ④ Ceramic brick has an artificial and hard psychological character; ⑤ Tile pavement has a modern, artificial, hard and cool psychological character; ⑥ Water permeable concrete has a modern and artificial psychological character; ⑦ Flag stone has a natural psychological character; ⑧ Granite has a modern and artificial psychological character; ⑨ Portland concrete has an artificial and hard psychological character; ⑩ Small compacted brick has an artificial, dynamic and modern psychological character; ⑪ Wood block pavement has a natural and traditional psychological character; ⑫ Asphalt concrete pavement has a modern, hard and artificial character. 2. On the results of the cluster analysis regarding psychological indexes for 12 pavement materials, pavement materials were categorized in 3 clusters. Among them, one cluster was mainly used as the most popular pavement material in our urban spaces and streets. From this point of view, psychological character for pavement material in our urban spaces and streets was not as various as we expected. 3. In conclusion, the proper selection of pavement materials was very important and the factors affecting the human psychological character should be considered in the design of urban spaces and streets.

• 한국구조물진단유지관리공학회 논문집
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• 제16권1호
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• pp.1-8
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• 2012

오늘날 첨단산업의 발전과 지구환경 문제의 심각성에 대한 인식이 증가하여 시멘트 산업에서도 다각화 측면에서 다양한 종류의 기술들이 활성화되고 있는 시점이다. 본 연구에서는 최근에 새로이 검토되고 있는 시멘트 대체 재료로서 천연제올라이트를 주원료로 사용한 제올라이트 시멘트 콘크리트에 관한 기초 물성에 대해 분석하는데 목적이 있으며, 악취 및 유독가스 제거기능이 우수하며 중금속, 암모니아와 같은 양이온성 오염물질을 제거하는 이온교환능, 흡착능, 분자체효과를 가지며 또한 다공성 물질이라 보온능력이 좋은 것으로 알려진 천연제올라이트와 알칼리 활성제(NaOH)의 양에 따라 콘크리트의 압축강도, 슬럼프, 블리딩 및 공기량 등을 실험하였다. 천연제올라이트 콘크리트의 압축강도 측정결과 거의 40MPa정도로 측정되었으며 슬럼프, 블리딩, 공기량 시험에서도 일반 콘크리트과 비슷한 성능을 나타내어 향후 고성능, 고기능성 건설재료로 사용 가능하다고 판단되어진다.

• 대한건축학회논문집:구조계
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• 제35권12호
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• pp.149-156
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• 2019

Recently, skyscraper building and apartment fires, which were rapidly spread out from a low floor to a rooftop, have become a frequent occurrence in mass media. This fire problems have a fatal disadvantage that the exterior wall finish of the building emits toxic gas in case of fire by using dry bit method or organic insulating material. Therefore, in order to remedy these problems, many exterior wall finishing construction methods have been proposed, but the current trend is to use existing construction methods due to problems such as economy, weight, and durability. On the other hand, in countries such as Germany and Japan, ceramic sidings are used as exterior finishing material for buildings, which is environmentally friendly, excellent natural beauty, long life, easy maintenance and high-quality exterior materials. However, those ceramic sidings have still the problems such as manufacturing cost and weight problem because of boosting the sintering temperature up to 1,350℃ or more. Also, conventional CRC, MgO, FRP sidings which are composed of pulp, glass fiber and organic materials, have been reports of deformation due to ultraviolet rays, discoloration, corrosion and scattering, surface rupture, lifting and peeling. Therefore, in this study as an alternative to solve this problem, halosite nano kaolin produced in Sancheong in Korea and frit flux were used to satisfy the required properties as ceramic siding using low temperature sintering (below 1,000℃) and lightweight materials such as pearlite. This study aims to design the optimal formulation and process of materials and to study the characteristics of nano-coated ceramic siding material development and to present relevant basic data. The findings show that ceramic siding for nanocoated building materials is excellent as a natural ceramic siding building material. The fire resistance of natural minerals and nano particle refining technology satisfy the bending strength of 80kgf / cm2, the volume ratio of 2.0 and the absorption rate of less than 10.0%.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 2017년도 춘계공동학술대회
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• pp.109-109
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• 2017

Cirsium setidens nakai belonging to cirsium has been reported to have various physiological activities including anticancer activity because it contains polyphenols, dietary fiber, minerals and vitamins. Despite these positive positive efficacies, however, no studies have studied cirsium setidens nakai products as biomaterials such as cellular metabolism and bone formation. Thus, the aim of this study was evaluate of osteogenesis differentiation a natural material extracted from cirsium setidens nakai. The natural materials in this studys in this studywere created by 40% ethanol extraction process and then dried. FabricatedFabricatedpowders were added to a medium at various concentrations (0.01, 0.05, 0.1, 0.2, and $0.25{\mu}g/mL$), and pure medium was used as a control. The natural material caused positive increases in cell metabolic activity and mineralized bone formation without cytotoxicity. In addition, we observed higher expression of genes such as ALP, BSP, Runx2 and COL1 in cirsium setidens nakai treatment cells. As a result, this study produced and investigated cirsium setidens nakai extracts and the natural materials showed potential biomaterials. In this research indicated that the cirsium setidens nakai extracts might have promising applications in areas of agricultural, biological and food engineering as a biomaterial.

• 한국의상디자인학회지
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• 제20권2호
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• pp.47-62
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• 2018

This study examined recycled fashion design utilizing natural images for application to recent trends. This study is significant in that it presents the possibility of the development of recycled women's wear design by reflecting the characteristics and expressions of natural images and using denim material, which is the most common clothing material for everyday life. The results of this study are summarized as follows. First, five types of women's clothing was produced, pursuing a natural design with a soft and feminine silhouette. Second, the colors used were blue and white, which could represent nature. Third, as for materials, this study used clothing that was to be thrown away: four pairs of denim pants and two denim dresses. This study chose denim cloth, with its great value for reuse, because of the characteristics of the strong and durable fiber, because everyone has more than one article of clothing made from denim and because it can be easily sourced. Fourth, for textile motifs, this study expressed a peaceful natural scenery with tropical animals and plants. In addition, this study further emphasized natural images using transfer media printing. This study has significance in that it presented the possibility of recycled fashion design and expanded the range of utilization using transfer media printing, a dyeing treatment to reduce the environmental burden.

• Computers and Concrete
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• 제31권2호
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• pp.85-95
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• 2023

Natural pozzolans are used as additives in cement to develop more durable and high-performance concrete. Pozzolanic activity index (PAI) is important for assessing the performance of a pozzolan as a binding material and has an important effect on the compressive strength, permeability, and chemical durability of concrete mixtures. However, the determining of the 28 days (short term) and 90 days (long term) PAI of concrete mixtures is a time-consuming process. In this study, to reduce extensive experimental work, it is aimed to predict the short term and long term PAIs as a function of the chemical compositions of various natural pozzolans. For this purpose, the chemical compositions of various natural pozzolans from Central Anatolia were determined with X-ray fluorescence spectroscopy. The mortar samples were prepared with the natural pozzolans and then, the short term and the long term PAIs were calculated based on compressive strength method. The effect of the natural pozzolans' chemical compositions on the short term and the long term PAIs were evaluated and the PAIs were predicted by using multiple linear regression (MLR) and adaptive neuro-fuzzy inference system (ANFIS) model. The prediction model results show that both reactive SiO₂ and SiO₂+Al₂O₃+Fe₂O₃ contents are the most effective parameters on PAI. According to the performance of prediction models determined with metrics such as root mean squared error (RMSE) and coefficient of correlation (R²), ANFIS models are more feasible than the multiple regression model in predicting the 28 days and 90 days pozzolanic activity. Estimation of PAIs based on the chemical component of natural pozzolana with high-performance prediction models is going to make an important contribution to material engineering applications in terms of selection of favorable natural pozzolana and saving time from tedious test processes.

• 한국실내디자인학회논문집
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• 제21권3호
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• pp.22-30
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• 2012

Nowadays the issue of environmental pollution and ecological destruction is not a simple issue but an important issue to be continuously considered. It is deemed that a study for recycled new materials is immediately required and this study is to analyze features and processing methods of new materials which can be used to interior space. We found the recycled new materials used for space through researching various web sits. And then we analyzed what the base materials are and classified that base materials are whether natural or artificial of the recycled materials. We classified processing methods of the recycled new materials after researching general processing methods. The result of this study would be an important material to the research and development of new finishing materials with consideration of environment and to the research for a guideline of applicable new materials. The results of this study are as follows : First, we could classify widely 2 categories into natural material and artificial material and then 10 subcategories into metal, glass, wood, rubber, stone, plastic, leather or fabric, ceramic, concrete and so on, and analyzed that which material is mostly used and whether it is single material or multiple material. In order to analyze the feature of processing method. Second, we could classify into 4 categories such as junction, surface process, molding, and insert, and found out which processing method is applied based on objects of research. Third, as an analysis result of the recycled new material feature, in order to develop various new materials, it is required to study on combination and application of 2 materials or more rather than single material. Four, as a analysis result of the processing method feature, I would like to suggest that development and application of various processing methods are required. Especially, it is necessary to grope for a way to develop new functional materials for interior space through a systemic research and analysis of processing method of other fields. Furthermore, a way to reuse recycled new materials should be considered in a stage of selection and application of processing method.

• 한국환경과학회지
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• 제24권5호
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• pp.633-639
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• 2015

The experience of natural dyeing is expected to be effective in promoting health through good exercise, in giving emotional stability based on the functional aromatic components of the dyeing material, and in improving self-esteem and increasing positive experiences through the behavior of creation. A natural dyeing material easily found around us, artemisia has long been used in food and Oriental medicine and was recently found to contain antioxidative, anticancer, deodorizing, antibacterial, anti-obesity, and anti-diabetes substances through chemical analysis. It has also been reported that group reminiscence therapy using the fragrance of artemisia is effective in relieving pain and depression and in promoting ego integrity in the elderly population. This study aimed to make a comparative analysis of dyeability, washing fastness, and deodorization between Artemisia princeps, Artemisia iwayomogi, and Artemisia annua, all of which are considered to be healthful and functional dyeing materials, among about thirty domestic plants in the genus of Artemisia and to provide basic data concerning natural dyeing in mind-peace education for the silver generation. The fabric dyed and post-mordanted at $80^{\circ}C$ for 40 minutes showed the greatest surface color variation; in this condition, artemisia princes (32.29) gave the greatest color difference, followed by artemisia iwayomogi (31.07) and artemisia annua (26.17). While all the types of artemisia were excellent in washing fastness, dry-cleaning fastness, and rubbing fastness at the fourth- or fifth-grade, light fastness was at the third grade for artemisia princes, at the second to third grade for artemisia annua, and at the second grade for artemisia iwayomogi; therefore, artemisia princes was found to give better fastness than the other two types of artemisia. In determining functionality of the fabric dyed with artemisia, deodorization test also found that the fabric dyed with artemisia princes had 20% higher deodorization.

• Nuclear Engineering and Technology
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• 제55권2호
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• pp.523-529
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• 2023

Cemented uranium tailings backfill created from alkali-activated slag (CUTB) is an effective method of disposing of uranium tailings. Using some environmental functional minerals with ion exchange, adsorption, and solidification abilities as backfill modified materials may improve the leaching resistance of the CUTB. Natural zeolite, which has good ion exchange and adsorption characteristics, is selected as the backfill modified material, and it is added to the backfill materials with cementitious material proportions of 4%, 8%, 12%, and 16% to prepare CUTB mixtures with environmental functional minerals. After the addition of natural zeolite, the uniaxial compressive strength (UCS) of the CUTB decreases, but the leaching resistance of the CUTB increases. When the natural zeolite content is 12%, the UCS reaches the minimum value of 8.95 MPa, and the concentration of uranium in the leaching solution is 0.28-8.07 mg/L, the leaching rate R₄₂ is 9.61×10^-7 cm/d, and cumulative leaching fraction P₄₂ is 8.53×10^-4 cm, which shows that the alkali-activated slag cementitious material has a good curing effect on the CUTB, and the addition of environmental functional minerals helps to further improve the leaching resistance of the CUTB, but it reduces the UCS to an extent.