• Title/Summary/Keyword: Breakaway

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Development of an Energy-Absorbing Device for a Crashworthy Sliding Post (감충성능을 갖는 슬라이딩 지주의 에너지흡수장치 개발)

  • Noh, Min-Hyung;Jang, Dae-Young;Lee, Sung-Soo;Han, Ki-Jang
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.40 no.5
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    • pp.445-454
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    • 2020
  • Non-breakaway crashworthy sliding posts move rigidly with a vehicle in the early stage of vehicle impact. During this stage, a vehicle imparts its linear momentum to the post, experiencing first-stage speed loss followed by second-stage loss from the crush of the energy-absorbing pipe (EAP) installed under the guide rail. An EAP is the key element of a crashworthy sliding post and should be confined to the post foundation. This paper covers the development of an EAP for a sliding post of 507 kg, which is a sliding post type frequently used in Korea for cantilever signs. Detailed explanations of the designs for an EAP structure using LS-DYNA impact simulation are given, and the crashworthiness of the systems are confirmed through crash tests. The EAP presented in this paper can accommodate impacts from 0.9 ton-60 km/h to 1.3 ton-80 km/h, and is applicable to foundations up to 2.7 m in length.

A Study on the Potential for Korean Traditional Pavilion from the Perspective of Nomad - Focused on Korean Traditional Pavilion in Andong Hahoe Folk Village - (노마드적 관점에서 본 전통 정자의 평면구성에 관한 연구 - 안동하회마을 내의 정자를 중심으로 -)

  • Jo, Jung-Hwa;Kim, Kai-Chun
    • Korean Institute of Interior Design Journal
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    • v.19 no.6
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    • pp.59-66
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    • 2010
  • The purpose of this study is to examine how the perception of lives and studies in the Joseon Dynasty period, and the concept of its sculptures can be reflected in Korean traditional pavilion place, from the perspective of Nomadism as a western philosophy of this era. Nomadism literally refers to way of life of peoples who do not live continually in the same place but move cyclically searching for temporary centres whose stability depends on the availability of food and water supply or pastures for their livestock. In recent years, the term encompasses three general types: job nomads, digital nomads and ubi-nomads, which represent distinct features of modern society. Its concept implies looking for the new creative possibility through the liberation of desire and the breakaway to another thinking through continuous formation and transformation. Likewise, Korean traditional pavilion is the architecture to take a quick rest while walking in the mountains. This open place thus connects surroundings with people who are allowed to assimilate with nature as well as train their mind by following the law of nature, in order to finally reach the celestial state of mind. Knowing how to see, enjoy and appreciate the arts very close to nature, our ancestors were able to learn aesthetic activities. After recognizing Korean traditional pavilion as the potential place of unification of heaven and men which is Korean scholor's lifestyle and outlook on the world, this study accordingly will identify the value and meaning of Korean traditional architecture according to Nomadism in the occidental point of view.

An analysis on the Deconstructed Visage in Fashion Illustration - Based on the Deconstructed Visage of Francis Bacon's Painting - (패션 일러스트레이션에 나타난 얼굴해체 - 프란시스 베이컨 회화의 얼굴해체를 바탕으로 -)

  • Choi, Jung-Hwa;Choi, Yoo-Jin
    • Fashion & Textile Research Journal
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    • v.15 no.6
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    • pp.874-885
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    • 2013
  • This study analyzes the visage in fashion illustration based on the deconstructed visage of Francis Bacon's paintings as well as analyzes fashion illustration works since 2000. The deconstructed visages in Francis Bacon's paintings are classified as blurring, elimination, distortion and division. The expressive methods and meanings in fashion illustration (according to categorization) are as follow. Blurring shows an ambiguous visage organ by the sweeping of the brush, removal of a boundary among the visage, body and clothes, gradation of organic line like visage shapes, stretching of the a plat combined to visage and fragmentation of visage. It represents an uncertainty of the fashion theme and image interpretation, impossibility of figure by ambiguity, fantastic effect and the induction of the uncanny. Elimination shows the background color's painting of a photo-montage, overlap of a cutting of visage's part and background of a plat, elimination of the visage and the elimination of eyes, nose or lips. It represents a weakened identity, the reinforcement of anonymity, creation of a violent image, and uncanny unfamiliarity. Distortion shows a distorted visage by free drawing, and unconscious drawing line, fluid digital body, combination of an unconscious curve, and an eccentric combination of the accidental. It represents the relief of specialty about realistic existence, hypothetical immateriality and fantasy. Division shows overlapped visages with different angles, the weird combination of a plural visage and different species and a plural breakaway of direction, and the position of several organs. It represents motion by power's trace, non-territory of species, ambiguity and uncertainty and the uncanny.

Plan for Increasing the Analysis and Understanding Skills of Literary Works based on Systems Thinking Technique (시스템 사고 기법 기반의 문학 작품 분석 및 이해력 신장 방안)

  • Kim, Hun-Hee
    • The Journal of the Korea Contents Association
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    • v.15 no.9
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    • pp.662-669
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    • 2015
  • The purpose of this study is to explore plan for increasing the analysis and understanding skills of literary works by using systemic thinking technique. This study used a literatures analysis method. The concrete study contents are as follows; First, it is centered on presenting values of literary education through analysing fairy tales conditions in Korean textbooks in relation to national curriculum for elementary and middle school. Second, it is to explore the features of systemic thinking technique. Third, it is to draw the instruction design model and application. Main expected effects of this study are breakaway from habitual routine, developing comprehensive and logical thinking ability, expanding fancy and imagination, cultivating innovative problem solving skill, inducing interest in literature, and increasing linguistic skills. That is, it is to be effective instruction strategy to enhance creativity and to cultivate character in classroom.

A Study on Weathering Processes of Tafoni in Mt. Cheonsaeng, Gumi, the Republic of Korea: Interpretation of Water Content Data using GIS Interpolation Analysis (구미 천생산 타포니의 풍화과정에 관한 연구: GIS 보간법을 활용한 함수율 측정 자료의 해석)

  • Shin, Jae-Ryul;Lee, Jin-Kook;Choo, Chang-Oh;Park, Kyung-Gun
    • Journal of the Korean earth science society
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    • v.36 no.6
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    • pp.543-552
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    • 2015
  • This study examines the processes of rock weathering and tafoni formation targeting tafoni at Mt. Cheonsaeng, Gumi-si, Gyeongsangbuk-do. In the study area, a frequency of tafoni is high in conglomerate and conglomeratic sandstone among regional sedimentary rocks, which means that an initial stage of the formation begins a breakaway of gravel from bedrock and also exfoliation from rock surface. Geomorphologically tafoni have intensively been developed at the southfacing slope with exposed rocks, which means that its formation was favorably controlled by environmental conditions including strong influences of mechanical weathering in winter and chemical weathering in summer times. The results of measuring water content at a tafoni-bearing rock surface using GIS interpolation analysis indicate that moisture rate in/around tafoni is higher than the periphery. Thus, it is considered that moisture distribution at a rock surface plays a role in its formation. Analysis of percipitation and secondary minerals induced by chemical weathering is in progress.

High-temperature Oxidation Kinetics and Scales Formed on Fe-2.3%Cr-1.6%W Alloy (Fe-2.3%Cr-1.6%W 합금의 고온산화 부식속도와 스케일 분석)

  • Bak, Sang-Hwan;Kim, Min-Jung;Lee, Jae-Ho;Bong, Sung-June;Kim, Seul-Ki;Lee, Dong-Bok
    • Journal of the Korean Ceramic Society
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    • v.48 no.1
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    • pp.57-62
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    • 2011
  • The T23 steel, whose composition was Fe-2.3%Cr-1.6%W, was arc-melted, and oxidized between $600^{\circ}C$ and $900^{\circ}C$ in air for up to 7 months. The amount of precipitates in the arc-melted microstructure was as large as 11.4 vol.%. The precipitates increased the oxidation rate of the arc-melted T23 steel. Owing to the low amount of Cr in the T23 steel, breakaway oxidation occurred after a few hours during oxidation above $700^{\circ}C$ in both arc-melted and as-received T23 steels. The scales that formed on arc-melted and as-received T23 steels were similar to each other. They consisted primarily of the outer $Fe_2O_3$ layer and the inner ($Fe_2O_3$, $FeCr_2O_4$)-mixed layer. The precipitates increased the microhardness and the oxidation rates.

Reliable Study on the Collision Analysis of Traffic Accidents Using PC-Crash Program (PC-Crash 프로그램을 이용한 교통사고 충돌해석에 관한 신뢰성 연구)

  • Kim, Jong-Duck;Yoon, Jun-Kyu
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.12 no.5
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    • pp.115-122
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    • 2012
  • Automobile collision analysis is composed of various shapes, and the speed variation working to the vehicle during collision are utilized as a very important factor in evaluating the degree of vehicle collision or passenger safety. So, the method of analyzing result values on the speed variation utilizing collision analysis program become necessary. This study utilized PC-Crash program in order to compare actual values and analyzed values of braking distance with the friction coefficient of road surface according to vehicle velocity. As a result, the smaller friction coefficient found to be larger error, and the maximum error range of collision velocity in case of each different vehicles (MATIZ, SONATA, or BUS) at the intersection showed 1.2%, 1.8%, 3.1% according to the difference of vehicle weight. Moreover, an accidental fall at IN-CHEON large bridge in order to reappear was verified with practicing simulation which has a slight error.

A Study on Crash Analysis of Vehicle and Guardrail using a LS-DYNA Program (LS-DYNA 프로그램을 이용한 차량과 가드레일의 충돌해석에 관한 연구)

  • Kwon, O-Hyun;Baek, Se-Ryong;Yoon, Jun-Kyu;Lim, Jong-Han
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.16 no.3
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    • pp.179-186
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    • 2016
  • A study is to research crash barriers for vehicles that prevent road breakaway of vehicles and protect car passengers and pedestrians as absorbing impulse. Protection performance tests on vehicle passengers were simulated by using a LS-DYNA program. Through repetitive simulation on various speed and angles, passenger protection performance according to different impact condition was contemplated. Variable setting for the simulation was calculated as the mean weight of domestic car sales. By analyzing NASS (National Automotive Sampling System) of NHTSA (National Highway Traffic Safety Administration) of the U.S., the actual speed and collision angle section of accidents were computed. As a result, we confirmed that THIV (Theoretical Head Impact Velocity) and PHD (Post-impact Head Deceleration) are increased according to the impact speed and angle. Also, when the vehicle hit the guardrail post, we could be confirmed that the passenger protection performance greatly decreased.

High-Temperature Oxidation Behavior of Fe-22%Cr-5.8%Al Alloy (Fe-22%Cr-5.8%Al 합금의 고온 산화 거동)

  • Kim, Song-Yi;Choi, Sung-Hwan;Yun, Jung-Yeul;Kong, Young-Min;Kim, Byoung-Kee;Lee, Kee-Ahn
    • Journal of the Korean institute of surface engineering
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    • v.44 no.1
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    • pp.13-20
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    • 2011
  • This study investigated the high temperature oxidation behavior of Fe-22%Cr-5.8%Al alloy and the oxidation kinetics of the alloy were discussed. Bulk samples were prepared by VAM (vacuum arc melting) and hot forging. High temperature oxidation testes were isothermally conducted up to 100 hours in 79%$N_2$+21%$O_2$ environment at three different temperatures ($900^{\circ}C$, $1000^{\circ}C$, $1100^{\circ}C$). The weight gain was measured after oxidation according to oxidation time (2, 4, 6, 8, 10, 15, 20, 25, 30, 60, 80, 100 hours). The weight gain significantly increased with increasing oxidation temperature. As the temperature increased, the oxidized samples showed sequential formation of $Al_2O_3$, Cr-rich oxide, Fe-rich oxide. The activation energy of high temperature oxidation was obtained as 306.63 KJ/mol. $Al_2O_3$ were developed on the surface in the early stage of oxidation, representing protective role of oxidation. However, Fe-based and Cr-based oxides leaded to breakaway of oxide layer, thus resulted in the significant increase of additional oxidation.

IRRADIATION PERFORMANCE OF U-Mo MONOLITHIC FUEL

  • Meyer, M.K.;Gan, J.;Jue, J.F.;Keiser, D.D.;Perez, E.;Robinson, A.;Wachs, D.M.;Woolstenhulme, N.;Hofman, G.L.;Kim, Y.S.
    • Nuclear Engineering and Technology
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    • v.46 no.2
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    • pp.169-182
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    • 2014
  • High-performance research reactors require fuel that operates at high specific power to high fission density, but at relatively low temperatures. Research reactor fuels are designed for efficient heat rejection, and are composed of assemblies of thin-plates clad in aluminum alloy. The development of low-enriched fuels to replace high-enriched fuels for these reactors requires a substantially increased uranium density in the fuel to offset the decrease in enrichment. Very few fuel phases have been identified that have the required combination of very-high uranium density and stable fuel behavior at high burnup. U-Mo alloys represent the best known tradeoff in these properties. Testing of aluminum matrix U-Mo aluminum matrix dispersion fuel revealed a pattern of breakaway swelling behavior at intermediate burnup, related to the formation of a molybdenum stabilized high aluminum intermetallic phase that forms during irradiation. In the case of monolithic fuel, this issue was addressed by eliminating, as much as possible, the interfacial area between U-Mo and aluminum. Based on scoping irradiation test data, a fuel plate system composed of solid U-10Mo fuel meat, a zirconium diffusion barrier, and Al6061 cladding was selected for development. Developmental testing of this fuel system indicates that it meets core criteria for fuel qualification, including stable and predictable swelling behavior, mechanical integrity to high burnup, and geometric stability. In addition, the fuel exhibits robust behavior during power-cooling mismatch events under irradiation at high power.