• Title/Summary/Keyword: material value

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Analysis of Heat Transfer Characteristics on Multi-layer Insulating Curtains Coated with Silica Aerogel (실리카 에어로겔이 흡착된 다겹보온커튼의 전열 특성 분석)

  • Jin, Byung-Ok;Kim, Hyung-Kweon;Ryou, Young-Sun;Lee, Tae-Seok;Kim, Young-Hwa;Oh, Sung-Sik;Kang, Geum-Choon
    • Journal of Bio-Environment Control
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    • v.28 no.3
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    • pp.273-278
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    • 2019
  • The multi-layer insulating curtains used in the experiment was produced in six combinations using non-woven fabric containing aerogel and compared and analyzed by measuring heat flux and heat perfusion rates due to weight, thickness and temperature changes. Using silica aerogel, which have recently been noted as new material insulation, this study tries to produce a new combination of multi-layer insulating curtains that can complement the shortcomings of the multi-layer insulating curtains currently in use and maintain and improve its warmth, and analyze the thermal properties. The heat flux means the amount of heat passing per unit time per unit area, and the higher the value, the more heat passing through the multi-layer insulating curtain, and it can be judged that the heat retention is low. The weight and thickness of multi-layer insulation curtains were found to be highly correlated with thermal insulation. In particular, insulation curtains combined with aerogel meltblown non-woven fabric had relatively higher thermal insulation than insulation curtains with the same number of insulation materials. However, the aerogel meltblown non-woven fabric is weak in light resistance and durability, and there is a problem that the production process and aerogel are scattering. In order to solve this problems, the combination of expanded aerogel non-woven fabric and hollow fiber non-woven fabric, which are relatively simple manufacturing processes and excellent warmth, are suitable for use in real farms.

Numerical Prediction for Fluidized Bed Chlorination Reaction of Ilmenite Ore (일메나이트광의 유동층 염화반응에 대한 수치적 예측)

  • Chung, Dong-Kyu;Jung, Eun-Jin;Lee, Mi Sun;Kim, Jinyoung;Song, Duk-Yong
    • Clean Technology
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    • v.25 no.2
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    • pp.107-113
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    • 2019
  • Numerical model that considered the shrinking core model and elutriation and degradation of particles was developed to predict selective chlorination of ilmenite and carbo-chlorination of $TiO_2$ in a two stage fluidized bed chlorination furnace. It is possible to analyze the fluidized bed chlorination reaction to be able to reflect particle distribution for mass balances and the chlorination reaction. The numerical model showed an accuracy with error less than 6% compared with fluidized bed experiments. The chlorination degree with particle size change was greater with a smaller particle size, and there was a 100 min difference to obtain a chlorination degree of 1 between $75{\mu}m$ and $275{\mu}m$. This was not shown to such a great extent with variation of temperature ($800{\sim}1000^{\circ}C$), and there was only a 10 min difference to obtain a chlorination degree of 0.9. In the first selective chlorination process, the mass reduction rate approached to the theoretical value of 0.4735 after 180 min, and chlorination changed the Fe component into $FeCl_2$ or $FeCl_3$ and showed nearly 1. In the second carbo-chlorination process, the chlorination degree of $TiO_2$ approached 0.98 and the mass fraction reached 0.02 with conversion into $TiCl_4$. In the first selective chlorination process, 98% of $TiO_2$ was produced at 180 min, and this was changed into 99% of $TiCl_4$ after an additional 90 min. Also the mass reduction rate of $TiO_2$ was reduced to 99% in the second continuous carbo-chlorination process.

Seismic response characteristics of the hypothetical subsea tunnel in the fault zone with various material properties (다양한 물성의 단층대를 통과하는 가상해저터널의 지진 시 응답 특성)

  • Jang, Dong In;Kwak, Chang-Won;Park, Inn-Joon;Kim, Chang-Yong
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.20 no.6
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    • pp.1061-1071
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    • 2018
  • A subsea tunnel, being a super-sized underground structure must ensure safety at the time of earthquake, as well as at ordinary times. At the time of earthquake, in particular, of a subsea tunnel, a variety of response behaviors are induced owing to relative rigidity to the surrounding ground, or difference of displacement, so that the behavior characteristics can be hardly anticipated. The investigation aims to understand the behavior characteristics switched by earthquake of an imaginary subsea tunnel which passes through a fault zone having different physical properties from those of the surrounding ground. In order to achieve the aim, dynamic response behaviors of a subsea tunnel which passes through a fault zone were observed by means of indoor experiments. For the sake of improved earthquake resistance, a shape of subsea tunnel to which flexible segments have been applied was considered. Afterward, it is believed that a D/B can be established through 3-dimensional earthquake resistance interpretation of various grounds, on the basis of verified results from the experiments and interpretations under various conditions. The present investigation performed 1 g shaking table test in order to verify the result of 3-dimensional earthquake resistance interpretation. A model considering the similitude (1:100) of a scale-down model test was manufactured, and tests for three (3) Cases were carried out. Incident seismic wave was introduced by artificial seismic wave having both long-period and short-period earthquake properties in the horizontal direction which is rectangular to the processing direction of the tunnel, so that a fault zone was modeled. For numerical analysis, elastic modulus of the fault zone was assumed 1/5 value of the modulus of individual grounds surround the tunnel, in order to simulate a fault zone. Resultantly, reduced acceleration was confirmed with increase of physical properties of the fault zone, and the result from the shaking table test showed the same tendency as the result from 3-dimensional interpretation.

A Study on the Concept of Records-Archives and on the Definition of Archival Terms (기록물의 개념과 용어의 정의에 관한 연구)

  • Kim, Jung-Ha
    • The Korean Journal of Archival Studies
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    • no.21
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    • pp.3-40
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    • 2009
  • It has passed ten years since modern records and archives management in our country launched. During times, it has dramatically developed in the fields of law, institution and education. However a study on the definition of records and archives was non be studied enough compared to development of various research fields. In fact the reason why study on the definition was non fulfilled is that some aspects such as historical, informational, archival perspective have been coexisting without order in Korea. This situation is the biggest barrier that archival science is to a disciplinary field. Historically, 'archivium' in Latin language had developed in starting of its means place, then whole entity of documents and those organic relations. In this point, archives is rigidly separate to material of Historical science which covers all of recorded. Unlike information which is produced in the process of intended themes and following its outputs like books, documents in archival science is made in the natural process of work. In addition, historical archives which finished the current and semi-current stage and transfer to the institute of permanent conservation after the process of selection so that it is historical and cultural value to satisfy its purpose of making. This changed trend is based on the Second World War and necessity of North American society which needs to effciency and transparency of work. In Korea, records and archives management has been dominantly affected by North American society and become a subject of not arrangement but of classification, not of transferring but of collection. It is also recognized as management of on formation on the all recorded or documents not as an whole documents and all organic relations. But the original type of recognition is the only technology, it cannot have dignity as a field of science.

Artificial Intelligence In Wheelchair: From Technology for Autonomy to Technology for Interdependence and Care (휠체어 탄 인공지능: 자율적 기술에서 상호의존과 돌봄의 기술로)

  • HA, Dae-Cheong
    • Journal of Science and Technology Studies
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    • v.19 no.2
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    • pp.169-206
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    • 2019
  • This article seeks to explore new relationships and ethics of human and technology by analyzing a cultural imaginary produced by artificial intelligence. Drawing on theoretical reflections of the Feminist Scientific and Technological Studies which understand science and technology as the matter of care(Puig de la Bellacas, 2011), this paper focuses on the fact that artificial intelligence and robots materialize cultural imaginary such as autonomy. This autonomy, defined as the capacity to adapt to a new environment through self-learning, is accepted as a way to conceptualize an authentic human or an ideal subject. However, this article argues that artificial intelligence is mediated by and dependent on invisible human labor and complex material devices, suggesting that such autonomy is close to fiction. The recent growth of the so-called 'assistant technology' shows that it is differentially visualizing the care work of both machines and humans. Technology and its cultural imaginary hide the care work of human workers and actively visualize the one of the machine. And they make autonomy and agency ideal humanness, leaving disabled bodies and dependency as unworthy. Artificial intelligence and its cultural imaginary negate the value of disabled bodies while idealizing abled-bodies, and result in eliminating the real relationship between man and technology as mutually dependent beings. In conclusion, the author argues that the technology we need is not the one to exclude the non-typical bodies and care work of others, but the one to include them as they are. This technology responsibly empathizes marginalized beings and encourages solidarity between fragile beings. Inspired by an art performance of artist Sue Austin, the author finally comes up with and suggests 'artificial intelligence in wheelchair' as an alternative figuration for the currently dominant 'autonomous artificial intelligence'.

Material Properties and Conservation of 『Collection of Yi Chungmugong』 in Manuscript (『이충무공전서』 정고본의 지질분석과 보존처리)

  • Lim, Se-Yeon;Ahn, Ji-Yoon;Yang, Min-Jeong
    • Korean Journal of Heritage: History & Science
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    • v.51 no.4
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    • pp.108-119
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    • 2018
  • "The Collection of Yi Chungmugong" manuscript is a hand-written manuscript of the volume 1 consisting of the Collection, published in 1795 and it seems to have completed the contents of the book by correcting the first part of the book before print. The book adopted a form of Seonjangbon(線裝本) of Ochimanjeongbeop(五針眼訂法) and was urgently needed some measures to preserve because it has been much damaged by stains, loss and oxidation due to moisture on the bottom of it. In addition, a scientific investigation was applied to find out the features of the quality of paper and fiber used for the book, which would be reflected in the process of the preservation. The characteristics of paper were measurmented for size(cm), thickness(mm), weight(g), basis weight($g/m^2$), density($g/cm^3$), chain line and laid lines($3{\times}3cm$). The measurement showed that the characteristics of paper used in royal books published in the late Joseon Dynasty. For the paper-fiber of the book, C stain was used and the technique revealed that the book is made of bast fibre of paper mulberry and its binding strings are cotton. SEM-EDS analysis was performed to verify the existence of additives in paper. As a result of the analysis, The crystallized calcium was detected in addition to the main components carbon(C) and oxygen(O). This artifact is the unique final version of "The collection of Yi Chungmugong", which has considerable value in terms of academic research, besides it helps to understand how to print books of Joseon Dynasty. And it also has a very accurate information of when and where the book was made, which primarily could be resources to conserve and restore for other book heritage.

Enhancement of Skin Permeation of Pyrus serotina var Leaf Extract Using Polymer Micelle and Liposome Containing Cell Penetrating Peptide (세포투과 펩티드를 함유한 고분자 미셀 및 리포좀을 이용한 배나무 잎 추출물의 피부 흡수 증진)

  • An, Gyu Min;Park, Su In;Kim, Min Gi;Heo, Soo Hyeon;Shin, Moon Sam
    • Journal of the Korean Applied Science and Technology
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    • v.36 no.3
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    • pp.685-699
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    • 2019
  • Antioxidant, antibacterial, and skin penetration tests were conducted to investigate the skin absorption of Pyrus serotina var leaf extracts using polymer micelles and their applicability to cosmetic ingredients. Total polyphenol content was found to be $118.83{\pm}9.39mg/g$ in Pyrus serotina var leaf ethanol extract and $106.89{\pm}4.45mg/g$ in Pyrus serotina var leaf hydrothermal extract. The DPPH radical scavenging activity was found to be the highest radical scavenging activity of $74.39{\pm}7.48%$ of the Pyrus serotina var leaf ethanol extract at the concentration of 500 mg/L. The SOD-like activity was $91.62{\pm}0.43%$, the highest value at the concentration of 1,000 mg/L in the hydrothermal extract. After the experiment, antioxidation, wrinkle improvement and whitening activity were confirmed, and the Pyrus serotina var leaf extract was highly likely to be realized as antioxidant and antibacterial material. In the skin penetration experiment with the Pyrus serotina var leaf ethanol extract, the permeation amount of total accumulated tannic acid was found to be Formulation 2 ($55.45{\mu}g/cm^2$), Formulation 1 ($46.43{\mu}g/cm^2$), Formulation 0 ($34.36{\mu}g/cm^2$). In the liposome's skin penetration experiment containing pear leaf hydrothemal extract, the total amount of accumulated tannic acid permeation was found to be Formulation 5 ($75.01{\mu}g/cm^2$), Formulation 4 ($64.01{\mu}g/cm^2$) and Formulation 3 ($36.60{\mu}g/cm^2$). Through this study, we confirmed the possibility of antioxidant and wrinkle effects of Pyrus serotina var leaf extract. In addition, as a result of skin penetration through the production of polymer micelles and liposome containing Pyrus serotina var leaf extract, It will be more usable in cosmetic industry.

Characteristics of Herbaceous Vegetation Structure of Barren Land of Southern Limit Line in DeMilitarized Zone (비무장지대 남방한계선 불모지 초본식생구조 특성)

  • Yu, Seung-Bong;Kim, Sang-Jun;Kim, Dong-Hak;Shin, Hyun-Tak;Bak, Gippeum
    • Korean Journal of Environment and Ecology
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    • v.35 no.2
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    • pp.135-153
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    • 2021
  • The demilitarized zone (DMZ) is a border barrier with 248 kilometers in length and about 4 kilometers in width crossing east to west to divide the Korean Peninsula about in half. The boundary at 2 kilometers to the south is called the southern limit line. The DMZ has formed a unique ecosystem through a natural ecological succession after the Armistice Agreement and has high conservation value. However, the use of facilities for the military operation and the unchecked weeding often damage the areas in the vicinities of the southern limit line's iron-railing. This study aimed to prepare basic data for the restoration of damaged barren vegetation. As a result of classifying vegetation communities based on indicator species, 10 communities were identified as follows: Duchesnea indica Community, Hosta longipes Community, Sedum kamtschaticum-Sedum sarmentosum Community, Potentilla anemonefolia Community, Potentilla fragarioides var. major Community, Prunella vulgaris var. lilacina Community, Dendranthema zawadskii var. latilobum-Carex lanceolata Community, Dendranthema zawadskii Community, Plantago asiatica-Trifolium repens Community, and Ixeris stolonifera-Kummerowia striata Community. Highly adaptable species can characterize vegetation in barren areas to environment disturbances because artificial disturbances such as soil erosion, soil compaction, topography change, and forest fires caused by military activities frequently occur in the barren areas within the southern limit line. Most of the dominant species in the communities are composed of plants that are commonly found in the roads, roadsides, bare soil, damaged areas, and grasslands throughout South Korea. Currently, the vegetation in barren areas in the vicinities of the DMZ is in the early ecological succession form that develops from bare soil to herbaceous vegetation. Since dominant species distributed in barren land can grow naturally without special maintenance and management, the data can be useful for future restoration material development or species selection.

Antioxidant Effects of Stewartia koreana Nakai Leaves and Branch Extracts (노각나무 잎과 가지 추출물의 항산화 효과)

  • Kim, Hye Soo;Park, Min Jeong;Kim, Soo Jeong;Kim, Bu Kyung;Park, JunHo;Kim, DaeHyun;Cho, Soo Jeong
    • Journal of Life Science
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    • v.31 no.2
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    • pp.229-236
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    • 2021
  • This study was carried out to evaluate the antioxidant properties of the dried leaves and branches of Stewartia koreana Nakai. The dried leaf and branch of S. koreana were extracted with 70% ethanol at 80℃. The antioxidant activities of ethanol extracts of S. koreana leaf (EESL) and S. koreana branch (EESB) were analyzed. The total polyphenol contents in EESL and EESB were 162.57±0.9 mg of GAEs/extract g and 59.1±0.9 mg of GAEs/extract g, respectively. The flavonoid contents in EESL and EESB were 59.1±0.9 mg of QEs/extract g and 4.7±0.1 mg of QEs/extract g, respectively. EESL showed a better scavenging ability with DPPH and ABTS than EESB, at 0.4 mg/ml. Moreover, EESL were more effective according to ORAC values than EESL. The toxicity of EESL was investigated using a WST-1 assay on the human skin fibroblast cell line CCD-986sk. Therefore, EESL can be used as a potential source of functional, naturally-sourced material in cosmetics as well as food.

Design and Management Direction of Smart Park for Smart Green City (스마트 그린시티 구현을 위한 스마트 공원 설계·관리 방향)

  • Kim, Yong-Gook;Song, Yu-Mi;Cho, Sang-kyu
    • Journal of the Korean Institute of Landscape Architecture
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    • v.48 no.6
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    • pp.1-15
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    • 2020
  • The purpose of this study is to propose a direction for designing and managing a smart park for realizing a smart green city and to present measures in the landscape field to foster related industries. The research process is as follows. First, the concept of a smart park was operationally defined through a literature review, and three principles to be considered in the process of creation and management were established. Second, in terms of the three principles, problems and implications for improvement were derived through an analysis of established cases of smart parks in new and pre-existing cities. Third, a pool of designs and management standards for each spatial component of a smart park was prepared through literature and case studies, and then further refined through brainstorming with experts in related fields. Fourth, measures were suggested to the government, local governments, and the landscape field to promote smart park creation and management. The main findings are as follows. First, the concept of a smart park is defined as "a park that contributes to securing the social, economic, and environmental sustainability of cities and local communities by supporting citizens' safe and pleasant use of parks and improving the management and operational efficiency by utilizing the digital, environment, and material technologies." Second, the three principles of smart parks are to improve the intrinsic value of parks, to improve the innovative functions of parks to solve urban problems, and to make the design, construction, and management process smart. Third, improvement implications were derived through the analysis of cases of smart parks creation in new and pre-existing cities. Fourth, the directions for smart park design and management were suggested in five aspects: green area, hydroponic facility area, road and plaza area, landscape facilities area, and park design method. Fifth, as for policy implications for revitalizing the construction and management of smart parks, the development of smart park policy business models by city growth stage, and park type, the promotion of pilot projects, the promotion of smart park projects in connection with the Korean New Deal policy, and smart park policies led by landscape experts were presented.