• Title/Summary/Keyword: Support structures

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Fabrication of complete denture using 3D printing: a case report (3D 프린팅을 이용한 양악 총의치 제작 증례)

  • Lee, Eunsu;Park, Chan;Yun, Kwidug;Lim, Hyun-Pil;Park, Sangwon
    • The Journal of Korean Academy of Prosthodontics
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    • v.60 no.2
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    • pp.202-210
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    • 2022
  • Recently with the advance in digital dentistry, the fabrication of dentures using computer-aided design and computer-aided manufacturing (CAD-CAM) is on the rise. The denture designed through a CAD software can be produced in a 3-dimensional manufacturing process. This process includes a subtractive processing method such as milling and an additive processing method such as 3D printing and in which it can be applied efficiently in more complex structures. In this case, complete dentures were fabricated using Stereolithography (SLA)-based 3D printing to shorten the production time and interval of visits in patient with physical disabilities due to cerebral infarction. For definitive impression, the existing interim denture was digitally replicated and used as an individual tray. The definitive impression obtained with polyvinyl siloxane impression material was including information about the inclination and length of the maxillary anterior teeth, vertical dimension, and centric relation. In addition, facial scan data with interim denture was obtained so that it can be used as a reference in determination of the occlusal plane and in arrangement of artificial teeth during laboratory work. Artificial teeth were arranged through a CAD program, and a gingival festooning was performed. The definitive dentures were printed by SLA-based 3D printer using a FDA-approved liquid photocurable resin. The denture showed adequate retention, support, and stability, and results were satisfied functionally and aesthetically.

Effect of Fermented Benincasa hispida cong. Extract on Promotion of Osteoblast Differentiation and Inhibition of Osteoclast Generation (동과 발효물의 조골세포 분화 촉진 및 파골세포 생성 억제 효과)

  • Choi, Ye-Eun;Yang, Jung-Mo;Yoo, Hee-Won;Cho, Ju-Hyun
    • Journal of Food Hygiene and Safety
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    • v.37 no.5
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    • pp.364-371
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    • 2022
  • The bones of the human body support the structures of the body and provide protection for a person's internal organs. Bone metabolic diseases are on the rise due to a significant increase in life expectancy over a short period of time. Therefore, we investigated the osteoblast differentiation promoting and osteoclastogenesis inhibitory activities of fermented Benincasa hispida cong. (HR1901-BS, HR1901-BSaf). We evaluated the alkaline phosphatase (ALP) activity of MC3T3-E1 mouse calvarial-derived osteoblasts. We also evaluated expression of ALP, osteocalcin (OCN), and runt-related transcription factor 2 (Runx2), which regulate osteoblast differentiation. To assess effects on osteoclast formation, tartrate-resistant acid phosphatase (TRAP) activity in RAW264.7 cells was analyzed. ALP activity increased by 121-136% and 140-156%, respectively in the presence of HR1901-BS and HR1901-BSaf. Expression of osteoblast differentiation factor also increased significantly. We also confirmed that HR1901-BS and HR1901-BSaf decreased TRAP activity in osteoclasts by 35-47% and 23-39%, respectively. Our results showed that fermented Benincasa hispida cong. (HR1901-BS, HR1901-BSaf) increase bone mineralization and osteoblast differentiation activity in MC3T3-E1 cells, and inhibit bone resorption activity in RAW264.7 cells. In conclusion, fermented Benincasa hispida cong. (HR1901-BS, HR1901-BSaf) can be used as an effective natural resource for preventing and treating bone-related diseases.

Material Characteristics and Making Techniques of Pottery by Type from the Oryang-dong Kiln Site in Naju, Korea (나주 오량동 요지 출토 토기의 기종별 재료 특성과 제작기법 연구)

  • Jin, Hong Ju;Jang, Sungyoon;Kim, Su Kyoung;Lee, Myeong Seong
    • Journal of Conservation Science
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    • v.36 no.6
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    • pp.440-455
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    • 2020
  • This study aims to examine the material characteristics of bowls and compare the making techniques of flat cup with cover and jar coffin from the Oryang-dong kiln site, Naju. Bowls, the most frequently excavated small pottery have similar material characteristics, including gray surface, fine-grained texture, and small-sized tempers such as quartz and feldspar, regardless of the excavation slopes. However, the firing temperature of the bowls mostly ranges from 950 to 1,100 ℃. It is estimated that the bowls had formalized making techniques, owing to the similar material composition and firing technique regardless of the excavation slope. The flat cups with cover have similar texture and mineral phases, except their poorly sorted inclusions. However, the jar coffins contain not only fine-grained minerals but also medium-grained quartz, feldspar, and biotite, showing a relatively wide range of firing temperatures. According to the geochemical results of pottery by type, it is assumed that chemical compositions are classified into two groups: small pottery(bowl and falt cup with cover) and jar coffins. In conclusion, small potteries such as bowls and flat cups with cover were made by removing the heavy minerals from raw materials, whereas jar coffins were made by adding medium-grained minerals to raw materials to maintain and support their structures, despite the same source materials. In addition, it is presumed that pottery making proceeded by selecting the source materials, preparing according to their use and controlling the firing temperature and environment.

The effects of UIC Cooperation Programs on Youth Employment (정부 산학연협력 지원의 고용효과 분석)

  • Kim, Sunwoo;Yoon, Yoon-Gyu
    • Korean small business review
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    • v.42 no.2
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    • pp.179-193
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    • 2020
  • In the rapid trend of social change, such as the 4th industrial revolution and the realignment of job structures, university-industry cooperation(UIC) is emphasized as a key factor in enhancing national competitiveness. The level of UIC in Korea is insufficient compared to national competitiveness, and despite the world-class R&D investment, there is a lack of linkage between the result of technology development and the industrial field, and the knowledge-transfer between university and industry is also insufficient. This paper analyzed the employment effects of UIC program supported by government, especially youth employment effects. The companies participating in the UIC program showed higher employment effect than the non-participating companies. In addition, the result of examining the employment growth rate of participating companies only for projects aimed at 'education and human resource development', show that employment growth rate after one year (total, youth employment) was significantly higher than that of non-participating companies, while employment growth after two years was not significant. UIC program need to have sustainability and systemicity so that they can be directly linked to the employment effects.

New Roles and Identity of Literary Writers from the Perspective of Cultural Intermediary (문화매개자 개념으로 바라본 문학 작가의 새로운 역할과 정체성)

  • Shim, Bo-Seon
    • Korean Association of Arts Management
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    • no.58
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    • pp.49-88
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    • 2021
  • Contemporary literary writers engage in multiple jobs and activities in the changing industrial and institutional environments to manage careers and produce literary value. The notion of art entrepreneurship envisages writers as the actors pursuing optimal rewards at both literary and economic levels by applying creative knowledge and skills to the management of career. In contrast, the notion of creative labor argues that writers go through career insecurity as they pursue self-fulfillment through work. This paper critically reviews two notions and suggests the notion of cultural intermediaries to better understand their production of literary value within the variety of relational contexts where they are situated. This paper analyzes the structures and characteristics of a wide range of intermediary practices by literary writers. Based on the analysis, I argue that the autonomy of literary value the writers construct and their status of entrepreneur-labourer are contingent upon the relational contexts within which they practice the intermediary work. I also suggest that literary writers by utilizing a variety of tactics cope with the changes that shape the autonomy of literature and invent new roles and identities as cultural intermediaries. Furthermore, literary writers develop not only self-management skills to adapt to the changing environments but also the collective capacity to cope with the constraints derived from the structural change of literary production and circulation. Finally, I argue that the art management discipline can reflect upon and support the creative endeavors of literary writers by embracing the critical understanding of structural changes suggested by the disciplines of humanities and social sciences.

A Study on Seismic Performance Evaluation of Road Tunnel according to Seismic Analysis Conditions (내진해석 조건에 따른 도로터널 내진성능평가에 관한 연구)

  • Choi, Byoung-Il;Kim, Chan-Hee;Noh, Eun-Cheol;Ha, Myung-Ho;Park, Si-Hyun
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.25 no.5
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    • pp.127-134
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    • 2021
  • When constructing a tunnel on a stable ground, stress is changed in the ground during excavation stage and installation of ground support materials. In the standards for safety evaluation of structures in use, it is suggested to perform numerical analysis reflecting the excavation stage. But method of seismic performance evaluation was not presented. Therefore, in this study, numerical analysis was performed with different analysis methods, and the results were compared and analyzed. As a result of the numerical analysis, seismic wave applied in the horizontal direction were no difference depending on the analysis methods. However, there was a big difference in the result according to the evaluation methods of tunnel member forces. When reviewing with the strength design method, the structure performance could be not satisfied depending on the existence or nonexistence of reinforcing bars. Based on these research results, it is suggested that the interpretation method should be clearly presented and reflected in the relevant standards.

Characteristics of Vegetation and Biota in the Gahwacheon Estuarine Wetland, Sacheon, South Korea: Proposals for the Ecosystem Conservation (사천 가화천하구습지의 식생 및 생물상 특성: 생태계 보전 대책의 제안)

  • Yeounsu, Chu;Kwang-Jin, Cho;Jeoncheol, Lim
    • Ecology and Resilient Infrastructure
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    • v.9 no.4
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    • pp.237-246
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    • 2022
  • Owing to their high bioproductivity and unique physical environment, estuarine wetlands are gaining importance in national biodiversity management and habitat conservation. With regard to conservation and management of estuarine wetlands, this study analyzed the ecological characteristics of Gahwacheon Estuarine Wetland, an open estuary with various habitat types. Data from vegetation and biotic surveys have shown that 12 plant communities of five physiognomic vegetation types, including lentic herbaceous vegetation, halophytic herbaceous vegetation, and chasmophytic herbaceous vegetation. Due to the discharge of Namgang Dam and the effect of the tide, vegetation are distributed along the narrow waterside area. In terms of biodiversity, a total of 715 species, including 12 endangered wildlife species, were identified. Species diversity was relatively high in sections I and III where various riverbed structures and microhabitats were distributed. Due to the effect of the brackish water area following the inflow of seawater, endangered wildlife of various functional groups were also found to be distributed, indicating the high conservation value of that area. The collection of ecological information of the Gahwacheon Estuarine Wetland can be used as a framework for establishing the basis for conservation and management of the estuarine ecosystem and support policy establishment.

Reinforcing Effect of Buildings Considering Load Distribution Characteristics of a Pre-compressed Micropile (선압축 보강마이크로파일의 하중분담 특성을 고려한 건물 보강효과에 대한 연구)

  • Lee, Kwang Hoon;Park, Yong Chan;Moon, Sung Jin;You, Kwang Ho
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.42 no.6
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    • pp.825-836
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    • 2022
  • Micropiles can be used to support additional load in extended building structures. However, their use brings about a risk of exceeding the bearing capacity of existing piles. In this study, pre-compression was applied to distribute the load of an existing building to micropiles, and an indoor loading test was performed to confirm the structural applicability of a wedge-type anchorage device designed to improve its capacity. According to the test results, the maximum strain of the anchorage device was 0.63 times that of the yield strain, and the amount of slip generated at the time of anchorage was 0.11 mm, satisfying structural standards. In addition, using MIDAS GTS, a geotechnical finite element analysis software, the effect of the size of the pre-compression, the thickness of the soil layer, and the ground conditions around the tip on the reaction force of the existing piles and micropiles were analyzed. From the numerical analysis, as the size of the pre-compression load increased, the reaction force of the existing pile decreased, resulting in a reduction rate of up to 36 %. In addition, as the soil layer increased by 5 m, the reduction rate decreased by 4 %, and when the ground condition at the tip of the micropile was weathered rock, the reduction rate increased by 14 % compared with that of weathered soil.

Development of Quality Evaluation and Management System for Assembled Temporary Equipment - Focused on Steel Pipe Scaffolding, System Scaffolding and Support - (조립 가설기자재 품질평가 및 관리 시스템 개발 - 강관 비계, 시스템 비계, 시스템 동바리를 중심으로 -)

  • Jang, Ji young;Lee, Ji yeon;Kim, Ha yoon;Lee, Jun ho;Kim, Jun-Sang;Kim, Jung-Yeol;Kim, Young Suk
    • Korean Journal of Construction Engineering and Management
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    • v.23 no.5
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    • pp.43-55
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    • 2022
  • Since assembled temporary equipment is widely used for construction work that should be carried out before this construction begins, it is essential to secure quality during assembly and prevent safety accidents caused by assembled temporary equipment after installation. However, it was investigated that most construction site managers are not aware of its importance, such as recognizing the quality management of assembled temporary equipment as a task of managing temporary structures that are dismantled after installation for this construction. The quality management work of assembled temporary equipment at the construction site is carried out in different ways for each construction site because there is no formalized procedure and the subject of performing. In addition, it is analyzed that the manager of the general construction company inspects and reflects the parts that need to be inspected without evidence, so transparency is not guaranteed and the result leads to a serious disaster. Therefore, the purpose of this study is to establish a document preparation-oriented system that provides systematic quality evaluation and management procedures for securing the quality of assembled temporary equipment, develops a checklist for quality evaluation and management, and supports history management on the web.

A Study on Shrinkage Crack of Steel Composite Concrete Box Structure (Transfer Girder) (강합성 콘크리트 박스구조물(트랜스퍼 거더)의 건조수축 균열에 대한 연구)

  • Choi, Jung-Youl;Kim, Dae-Ill
    • The Journal of the Convergence on Culture Technology
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    • v.8 no.6
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    • pp.685-691
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    • 2022
  • This study was based on the steel composite concrete box structure (Transfer girder) which was installed to support the skyscrapers directly above the subway line. In this study, it was analytically proved that the cause of cracks on the steel composite concrete box structure were the shrinkage cracks by comparing the results of crack investigation and numerical analysis. As the results, it was found that the internal temperature difference between concrete and steel members occurred according to the shape of the steel frame embedded in concrete, the location of vertical stiffener, and the closed section area. The narrower spacing of vertical stiffener was occurred the internal temperature concentration of the structure and the temperature difference increased. And the location of higher thermal strain and temperature were similar to the location of actual cracks by the visual inspection. Therefore, the internal temperature concentration parts were formed according to the presence and spacing of the vertical stiffeners and the inspection passage in the central part of the structure. The shrinkage cracks were occurred by the restrained of temperature expansion and contraction of the concrete. As the results of this study, it was important to separate and manage the non-structural cracks caused by shrinkage and the structural cracks in the maintenance of serviced steel-composite concrete structures.