• Title/Summary/Keyword: Repair materials

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Conductive Properties of Thermoplastic Carbon Fiber Reinforced Plastics Highly Filled with Carbon Fiber Fabrics and Conductive Carbon Fillers (탄소섬유 직물 및 전도성 탄소 필러가 고충진 된 열가소성 탄소섬유강화플라스틱의 전도 특성)

  • Kim, Seong Yun;Noh, Ye Ji;Jang, Ji-un;Choi, Seong Kyu
    • Composites Research
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    • v.34 no.5
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    • pp.290-295
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    • 2021
  • The application of lightweight structural composites to automobiles as a solution in line with global fuel economy regulations to curb global warming is recognized as a megatrend. This study was conducted to provide a technical approach that can respond to the issue of replacing parts that require conductive properties to maximize the application of thermoplastic carbon fiber reinforced plastics (CFRPs), which are advantageous in terms of repair, disposal and recycling. By utilizing the properties of the low-viscosity polymerizable oligomer matrix, it was possible to prepare a thermoplastic CFRP exhibiting excellent impregnation properties while uniformly mixing the conductive filler. Various carbon-based conductive fillers such as carbon black, carbon nanotubes, graphene nanoplatelets, graphite, and pitch-based carbon fibers were filled up to the maximum content, and electrical and thermal conductive properties of the fabricated composites were compared and studied. It was confirmed that the maximum incorporation of filler was the most important factor to control the conductive properties of the composites rather than the type or shape of the conductive carbon filler. Experimental results were observed in which it might be advantageous to apply a one-dimensional conductive carbon filler to improve electrical conductivity, whereas it might be advantageous to apply a two-dimensional conductive carbon filler to improve thermal conductivity. The results of this study can provide potential insight into the optimization of structural design for controlling the conductive properties of thermoplastic CFRPs.

A Study on the Ecological Characteristics and Changes of the Shigeru Ban Exhibition Space (시게루 반 전시공간의 생태적 특성과 변화 연구)

  • Tian, Hui;Yoon, Ji-Young
    • The Journal of the Korea Contents Association
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    • v.22 no.2
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    • pp.147-161
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    • 2022
  • This study examined changes in the ecological characteristics and design characteristics of Ban's exhibition space in three representative temporary exhibition halls and three permanent exhibition halls designed by Ban Shigeru since 2000. Through the investigation of the concepts and characteristics of ecological architecture, the design characteristics of exhibition space, the analysis framework of the design characteristics of exhibition space and the design elements of ecological architecture is obtained. The analysis results show that there are big changes between the temporary exhibition space and the permanent exhibition space in terms of building scale, space composition, function, materials and technology. On the one hand, the temporary exhibition space used recyclable materials, such as paper tubes, containers to be assembled on site into a single-layer space focused on display. The assembly method was simple and the construction period was short. After the exhibition, the exhibition space were dismantled. The materials were either transported to the next display site or recycled and reused. On the other hand, the permanent exhibition space used reinforced concrete as the main structure, and used a large amount of wood and glass materials to construct a multi-layered composite cultural space that separated the exhibition space and the leisure space. In terms of ecological characteristics, the building materials of the temporary exhibition space were recycled and no industrial wastes were generated after the demolition. The permanent exhibition hall uses eco-friendly wood for the roof and walls, so it is easy to replace and repair. Both types of exhibition halls are changing ecological architecture in a more sustainable direction by saving resources and energy through natural light and ventilation.

Tree-Ring Dating of Wood Elements of Daejojeon, Changdukgung (창덕궁 대조전 목부재의 연륜연대 측정)

  • Park Suh-Young;Park Won-Kyu;Kim Yo-Jung
    • 한국문화재보존과학회:학술대회논문집
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    • 2005.11a
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    • pp.300-305
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    • 2005
  • Tree-ring chronologies can be used to date historical buildings and furniture by matching them with the chronologies of living trees or previously dated samples. Tree-ring dating gives a calender year to each tree ring and produces the felling dates of logs or woods which had been used for buildings. In Korea, several chronologies of Japanese red pine(Pinus densiflora Sieb. et Zucc.,'sonamu' in Korean), a major species for the wooden building materials, have been developed and used for dating historical buildings. Daejojeon of Changduck Palace is known to be reconstructed in A.D. 1920 after burned-out in A.D. 1917. Instead of new woods, Daejojeon was reconstructed by reusing the woods of Kyotaejeon in Kyungbok Palace. We sampled total of 26 wood samples which were replaced during the repair process of Daejojeon in 1995. Felling dates of the samples were determined by the dendrochronological crossdating method. Crossdating method employs graphic comparison of the master patterns (ring-width plots of living trees or known dates) with those of the sample chronologies of unknown dates. The cutting dates of Daejojeon woods were divided in two groups. One was the late 1860s and the other 1880s. The results confirmed that Kyotaejeon was reconstruced first in the A.D 1860s and then in late 1880s after burning out in 1876.

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An Experimental Study on Improvement in Waterproofing Performance of Ground Structures applied to Synthetic Polymeric Sheet of monolithic adhesion Type (일체부착형 합성고분자 시트를 이용한 지하구조물 방수 성능향상에 관한 실험적 연구)

  • Kang, Hyo-Jin;Song, Jei-Young;Kwon, Shi-Won;Oh, Sang-Keun
    • Journal of the Korea Institute of Building Construction
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    • v.5 no.3 s.17
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    • pp.125-129
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    • 2005
  • The waterproofing in slab and wall of underground structure, have a couple of construction methods which are inside waterproofing methods for inner surface, and outside waterproofing methods for out wall and slab surface waterproofing. In resent years, however, it has been adapted the inside waterproofing construction method, as increasing of construction expenses cost and low workability and technology, nevertheless, outside waterproofing has set a most high value construction method. In inside waterproofing construction method, it is difficult to repair and assure durability and safety for concrete which has direct water-press. So, It is necessary for adopt the outside waterproofing method. For that reasons, this study based on the application for outside waterproofing method on the under ground structure, to more increase durability, to introduce mono adhesive sheet waterproofing materials. as considering chemical, physical properties.

Evaluation of Physical Properties and Long-term Stability of Expansion Materials for Emergency Repair by Temperature (긴급복구용 팽창재료의 온도에 따른 물리적 특성 및 장기 안전성 평가)

  • Park, Jeongjun;Kim, Kisung;Kang, Hyounhoi;Kim, Ju-Ho;Hong, Gigwon
    • Journal of the Society of Disaster Information
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    • v.14 no.1
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    • pp.79-88
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    • 2018
  • In this study, the changes of the expansion and strength according to the temperature of the emergency repairing expansion material were examined by cup foaming test and uniaxial compressive strength test, and the accelerated compression creep test was carried out to confirm the long term stability. Ramp & Hold test and accelerated compressive creep test were performed to evaluate the creep performance. The short - term creep test was used to determine the initial creep strain of the expanding material. The isothermal method using time - To evaluate the long - term compressive creep performance.

Study on Curriculum of Denture clinician (의치사의 교육과정에 관한 연구)

  • Park, Myung-Ho;Bae, Bong-Jin;Lee, Hwa-Sik;Lee, Hee-Kyung
    • Journal of Technologic Dentistry
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    • v.32 no.1
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    • pp.47-56
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    • 2010
  • As Korea is entering an aging society, the number of elderly people who need new denture or who have problems with their existing denture or adjacent tissue is increasing and it will double in 2018. Therefore, denture clinician system will lessen patients financial burden and introduce market economy to the dental prosthesis field. Therefore, Korea needs to adopt denture clinician system as soon as possible as USA or Canada to increase people s accessibility in quality and quantity. Denture clinician will determine the size and shape of denture after performing oral examination, make impression using various materials, fabricate denture, deliver and adjust completed denture to the patient, repair denture, and carry out financial management in the denture fabricating company or manage human resources. Considering denture clinicians services, American and European education system seems to be close to our system. Therefore, in this study, basic curriculums of several countries in Europe and America were reviewed and curriculum that meets Korean situation was suggested.

A Study on the Abrasion Resistance of Polymer - Modified Mortar According to Curing Conditions (양생조건에 따른 폴리머 시멘트 모르터의 내마모성에 관한 연구)

  • Jo, Young-Kug;So, Seoung-Young
    • Journal of the Korea Institute of Building Construction
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    • v.5 no.4 s.18
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    • pp.115-120
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    • 2005
  • In recent years, polymer-modified mortars using polymer dispersions have been widely used as finish and repair materials in the construction industry because of their excellent properties compares to those of ordinary cement mortar. Especially, the adhesion improvement of ordinary cement mortar and concrete has attracted a great deal of attention from researchers, and several unique and simply applicable techniques for the adhesion improvement have been developed. The purpose of this study is to evaluate the abrasion resistance of polymer-modified mortar according various curing methods. The polymer-modified mortar are prepared with various polymer-cement ratios, and are subjected to three curing methods such as dry rure, standard cure and freezing and thawing cure after two curing methods, and then tested for abrasion. From the test results, the polymer-modified mortars with various polymer-cement ratios have some superior abrasion resistance compared with plain mortar. The abrasion resistance of polymer-modified mortars increase with an increase in the polymer-cement ratio, and is better under water cure than any other curing methods. It is concluded that the abrasion resistance of cement mortar is markedly improved by modifying of polymer dispersion.

Performance Appraisal of the Ceramic Metal Resin Paints for Waterproof and Anti-Corrosion to Improve the Property of Concrete Structure (콘크리트 구조물의 표층부 내구성 증진을 위한 세라믹 메탈계 방수$\cdot$방식재 도료의 성능 평가 연구)

  • Jun Byung-Hun;Kim Jin-Sung;Kang Hyo-Jin;Oh Sang-Keun
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2005.05a
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    • pp.113-117
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    • 2005
  • The ceramic metal resin paints for waterproof and anti corrosion is not long history in development of materials even many actual result. So far, no standard have been given to construction and maintenance method, Quality and property, it is real state that cannot afford to proper quality control in job site or production. This study has been test for the ceramic metal resin paints for water and anti corrosion, as the result, it have proper performance of job site and mechanical performance of compare to other existing. In particular, tensile strength indicates more high about $14.1N/mm^2$ than epoxy resin paints, and in elongation per unit length is more high It is shows having better adhesive strength than epoxy resin paint for crack on the concrete structure. Moreover, The ceramic metal paint for water and corrosion proofing have to have main performance is watertightness and resistance for external impact, chloride ion permeation, drinkable water elution.

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The Development of Detection System of Conveyer Belt Damage using Magnetic Flux (자기장을 이용한 컨베이어 벨트 파손 감지장치 개발)

  • Yang, Keun-Ho;Min, Byung-Woon
    • The Journal of the Korea institute of electronic communication sciences
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    • v.8 no.6
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    • pp.815-822
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    • 2013
  • In this paper, the research is to develop a system that can detect the breakage of the rubber belt conveyor system in the transport of the raw materials required for the operation of logistics. We are to develop a system that can detect the breakage of the belt due to the electronic system of belt breakage occurs by placing the material on the inside of the belt, electric induction to minimize the damage of the belt. The belt repair costs, or reorder the steps of the logistics transit time can be reduced. Induced in the coil, and belt embedded in the transmitted signal as a way to detect the breakage of the belt was to detect the damage of the belt by detecting the electrical phenomena induced in the coil at the receiving end.

A Study of a Dike Design Considering a Leakage Velocity at an Opening Hole in Case of a Leakage Accident (누출사고 시 저장탱크 위험물 누출속도를 고려한 방유제 설계에 관한 연구)

  • Lee, Jae Yeol;Kim, Dong Hyun;Ban, Soon Hee;Lee, Chang Jun
    • Journal of the Korean Society of Safety
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    • v.32 no.6
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    • pp.40-45
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    • 2017
  • Chemical accidents generated during maintenance, repair, and normal operation, such as dispersion, fire, and explosions, can cause massive losses like a 2012 hydro fluorine leak in Gumi, South Korea. Since this accident, many researches have studied physical mitigation systems. However, due to many difficulties including potential costs and lack time, it is really hard for many companies to install mitigation systems without prior knowledge. Thus, the efficacy of mitigation system should be evaluated. This study assesses a dike design considering the fluid velocity at an open hole when a leakage accident occurs. It is assumed that leakage materials follow a free fall motion. Throughout case studies, a current KOSHA guide for a dike design was evaluated and new guidelines handling various conditions were proposed.