• Title/Summary/Keyword: 단면조사 연구

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Development of Hybrid OCB Beam for the Long-span Building Structures (장경간 건축구조를 위한 하이브리드 OCB보의 개발)

  • Lee, Doo-Sung;Kim, Sang-Yeon;Kim, Tae-Kyun
    • Land and Housing Review
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    • v.6 no.3
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    • pp.129-138
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    • 2015
  • The building structure in Korea is planned to maximize the use of space in recent. The hybrid OCB(Optimized Composite Beam) beam is developed to take advantage of using the space. The OCB beam is composed of the steel H-beam section reinforced by open strands in negative moment zone and the pretensioned PSC concrete section in positive zone. Flexural behavior of typical architectural hybrid OCB beam section was investigated by F.E.M. The 15m, 20m, 30m OCB models were tested on nonlinear material and geometry under static loading system. Following results are obtained from the analysis; 1)The OCB beam develop initial flexural cracking over full service loading. 2)Overall deflections of OCB beam under the service loads are less than those of the allowable limits in KCI Code(2012). 3)The ultimate load capacity get over the nominal strength of the OCB main section. The OCB beam is verified of structural reliability from the finite element analysis.

Effect of 2-butoxyethanol Additive in the Casting Solution on the Characteristics of Nonsolvent Vapor Induced Phase Inversion PES Membranes (비용매증기 유발 상 전이 공정을 이용한 PES 멤브레인 제조에 있어 2-butoxyethanol 첨가 효과)

  • Kim, No-Won
    • Membrane Journal
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    • v.20 no.1
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    • pp.76-86
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    • 2010
  • This study investigated the effect of 2-butoxyethanol (BE) as a nonsolvent additive, relative humidity and air contact time on the structure formation of microfiltration membranes, permeation and morphology properties in phase inversion process. The membranes were prepared by using polyethersulfone (PES)/Dimethyl formamide (DMF)/p-toluenesulfonic acid (TSA)/Polyvinylpyrrolidone (PVP)/BE casting solution and water coagulant. Casting solutions containing various concentration of BE were exposed to a water vapor, under 60 and 80% of relative humidity for 40 and 90 sec, which would be absorbed on. The correlations between the membrane permeation properties and surface/inner structures of membrane were investigated. The characterization of membranes was carried out by a capillary flow porometer, a FE-SEM and a water permeation test apparatus. The surface structure of PES membranes was affected by the exposure time as well as the relative humidity strongly. Furthermore, the addition of BE helped control surface and inner structure at certain humidity and exposure time.

Research on Material Components and Production Method for Metal Bound Rim of 'Bowl, White Porcelain with Impressed Floral Design and Sliver Bound Rim' and 'Bowl, White Porcelain with Silver Bound Rim' (청백자인각화훼문은구완(靑白磁印刻花卉文銀鉤盌)과 백자은구대접(白磁銀鉤大楪)의 금속 테두리 재질 성분 및 제작 방법 연구)

  • Byun, Sungmoon;Hwang, Hyunsung
    • Conservation Science in Museum
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    • v.9
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    • pp.1-15
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    • 2008
  • We observed the section and microstructure by Scanning Electron Mirrorscope (SEM) for 4 'Bowls, white porcelain with impressed floral design and sliver bound rim' and 1 'Dish, white porcelain with sliver bound rim', which was manufactured by reverse firing and metal bound rim was wrapped to the part of not being spread glaze at inlet, in Jingdezhen white porcelains, the relics dug from the seabed of Shinan conserved in National Museum of Korea, and found that the ingredient of metal rim was not silver but tin as a result of measuring by BEI of Energy Dispersive Spectroscopy (EDS). And as a result of survey with Fourier transform infrared spectroscopy(FT-IR) for checking the method of joining metal rim of mouth part, it was found that joining was made with materials made of lacquer.

Weight Reduction and Dyeing Properties of Sea-island Type PET Nanofilament Circular Knitted Fabric (해도형 나노필라멘트 편성물의 감량 및 염색성)

  • Kim, Hyun-Sung;Lee, Jung-Jin;Shin, Eun-Suk
    • Proceedings of the Korean Society of Dyers and Finishers Conference
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    • 2011.03a
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    • pp.52-52
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    • 2011
  • 나노필라멘트는 단면직경이 수백 나노미터에서 수십 나노미터 수준인 초극세 장섬유를 말하며, 해도형 복합방사로 얻어진 섬유를 알칼리 감량을 통해 해성분을 용출하여 도성분에 해당하는 나노필라멘트를 얻는다. 이러한 나노필라멘트사는 초극세와 마찬가지로 단위중량당 표면적이 크고, 작은 굴곡반경 및 낮은 굴곡 반발성으로 인하여 일반 합성섬유에 비하여 고가성 및 새로운 기능성을 부여하는 제품에 응용 될 수 있다. 특히 나노필라멘트를 이용한 편물제품으로 경편물은 wiping cloth 등 산업용도에 적용되며, 환편물은 인조피혁 등 의류용으로 사용된다. 나노필라멘트 편물은 원사섬도, 편물의 조직, 밀도 및 중량 등에 따라 분할율과 용출 특성이 상이하므로 후가공 공정에 있어서 감량공정은 매우 중요하다. 또한 나노필라멘트와 같은 세사의 경우 일반사보다 비표면적이 증가하여 동일한 염색조건에서 옅은 색상을 나타낸다. 이로 인해 같은 색상을 위하여 보다 많은 염료를 투입해야 하며, 결과적으로 견뢰도 문제가 발생할 우려가 있다. 이 연구에서는 해도형 나노필라멘트 PET 원사와 일반 PET사를 복합한 2종의 편물을 이용하여 알칼리감량특성 및 3가지 분산염료에 대한 염색성과 견뢰도를 조사하였다. 알칼리 처리조건에 따른 감량률을 측정함으로써 각 편물의 이론 감량률에 도달하는 지점을 확인하고, SEM사진 분석을 통하여 해도사의 감량정도 및 분할특성을 확인하였다. 나노필라멘트 편성물은 염료농도가 증가함에 따라 지속적으로 K/S 값이 증가하였으나, 전체적으로 낮은 K/S값을 얻었다. 또한 염색온도가 110에서 $100^{\circ}C$로 증가함에 따라 K/S값이 감소하였는데, 이는 고온에서 분산염료가 나노필라멘트로부터 일반 PET사로 이염이 더 많이 발생하였기 때문이라고 생각된다. 세탁견뢰도의 경우 양호 또는 우수하였으나, 일광견뢰도의 경우 1등급으로 매우 낮아 이를 개선하기 위한 노력이 향후 진행되어야 할 것이다.

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An Investigation of Tunnel Behaviour Using a Time-based 2-D Modelling Method (시간-파라미터 법에 의한 터널거동 특성 연구)

  • Shin, Jong-Ho
    • Journal of the Korean Geotechnical Society
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    • v.18 no.1
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    • pp.17-28
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    • 2002
  • Tunnel construction is a complex three dimensional operation. Since, however, it is neither possible nor useful to simulate all conditions and parameters in detail, a simplified two dimensional model is commonly employed in practice. The simulation of three dimensional conditions by a two dimensional model should use empirical parameters. The numerical predictions indicate that analysis results are highly dependent on the parameters. An improved modelling method based on time was adopted to account for three dimensional effect at the tunnel heading and time dependent nature, and used to perform an analysis of tunnelling in decomposed granite. The effects of weathering degree, tunnel shape and multi-drift excavation were investigated by using the method. It is identified that a structural benefit can be obtained by adopting a horse-shoe-shaped cross section with multi-drift excavation in mixed-force ground condition.

Optimized Design of Mine Span Considering the Characteristics of Rockmass in Soft Ground (연약암반에서 암반의 특성을 고려한 광산갱도의 최적 설계)

  • Jang, Myoung Hwan;Ha, Taewook;Jeong, Hee Sun
    • Tunnel and Underground Space
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    • v.28 no.2
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    • pp.125-141
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    • 2018
  • For a long-term mine development plan, the determination and design of mine tunnel size are very important because it is the basis of plans for equipment, transportation and operation. The ${\bigcirc}{\bigcirc}$ mine has had a difficulty in changing the mining plan due to the design of the tunnels with an emphasis on productivity improvement, and much effort was needed to maintain the mine tunnel. In this study, we designed the mine tunnel with optimized tunnel span considering the mechanical properties of rockmass and established the support plan. To do this, the estimation of the mechanical parameters(Swelling pressure, deformation coefficient and earth coefficient), field investigations and various analyses were carried out. As a result, it was necessary to consider the downsizing of the tunnel section in order to maintain the tunnel stability and dimension by using the roof bolt and analyzed that various functional constructions of the support material and method would be required to maintain the current tunnel size.

A Study on the Structural Reliability (구조물(構造物)의 신뢰성(信賴性)에 관한 소고(小考) -원형단면의 인장재를 중심으로-)

  • Son, Seung Yo
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.5 no.2
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    • pp.51-57
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    • 1985
  • In the design of civil engineering structures, the designers are invariably faced to the uncertainties and the randomness of the design parameters such as material properties and loads. Even when the structures are built, the actual geometries of the structures are also subject to their random variations from their nominal design values. Thus, the reliability of a structure in terms of these uncertainties and variations becomes a matter of great concern to the structural designers. This study employs the First Order Second Moment Method to evluate numerically the reliability of a simple tension member and discusses the influence on the final failure probability of that structure due to: 1) use of equivalent normal distribution in place of non-normal distribution, 2) linearization of non linear limit state equation. A discussion is also made on the necessity of fundamental studies on the distrubution characteristics of the strength of locally produced construction materials and those of the loads frequently encountered in the structural design.

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The Characteristics and Frost Creep of Granite Regoliths (화강암 풍화층의 특성과 결빙포행)

  • Kwon, Soon-Shik
    • Journal of the Korean association of regional geographers
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    • v.9 no.4
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    • pp.534-545
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    • 2003
  • The main purpose of this paper is to describe the granitic regolith and frost creep phenomena in Daegwanryung area in order to demonstrate the relationship of the weathered materials and the surrounding surface, in order to point out that the characteristics of this particular complex of granitic regolith most closely resemble those of soil frost creep phenomena formed elsewhere under periglacial conditions. For this study, the writer has clarified their structure and its associated milieux, with a group of methods and techniques, field survey, micro-morphological analysis, granulometry of weathered materials etc. Such facies of granitic regolith in situ with silty heterometric materials and micas are prone to be deformed by cryo-suction as well as deep freezing. It was probably formed by cryogenic activity, or frost creep in the periglacial climate of a very cold and humid condition.

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An Experimental Study on the Flashback and Re-ignition Structure with a V-gutter type Flameholder (V-gutter형 보염기에서 발생하는 화염의 역화 및 재점화 구조에 관한 실험적 연구)

  • Jeong, Chan-Yeong;Kim, Tae-Sung;Song, Jin-Kwan;Yoon, Young-Bin
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2011.11a
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    • pp.603-607
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    • 2011
  • Structure of flashback and reignition occurring near flameholder was experimentally investigated in a model combustor with V-gutter flameholder. The combustor has a long duct shape with cross section of $40{\times}40mm$ and City Nature Gas(CNG) were used as fuel. Measurements of chemiluminescence with high speed camera was used for visualization of flame structure. In the lean case, flashback distance depend on equivalent ratio. New flame occurred at the front tip of flameholder when flashback. Flashback flame moved toward downstream direction of combustor because mixture flow velocity had increased, and then re-ignition was caused by entering flow into recirculation zone that is formed behind the flameholder.

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Report on the Annual Reproductive Cycle and Imposex Phenomenon of the Rock-Shell, Thais clavigera in Jeju Port (제주항 내에 서식하는 신복족류 Thais clavigera의 연중 생식주기 및 임포섹스 현상에 관한연구)

  • Yang, Hyun-Sung;Kim, Bong-Kyu;Park, Heung-Sik;Choi, Kwang-Sik
    • The Korean Journal of Malacology
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    • v.26 no.1
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    • pp.97-105
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    • 2010
  • Annual gonad development of the rock shell, Thais clavigera distributed in Jeju Port was investigated over a 12 month period from March 1998 to February 1999. Monthly change in gonad development was examined using histology. Gametogenesis of T. clavigera in the study area initiated as early as in October and fully ripe eggs could be observed from May to July. Percent gonad area (PGA) also increased rapidly from May to July then dropped in August when the water temperature remained $22.6-24.5^{\circ}C$, suggesting that rock shell released their eggs during this period. All female rock shell collected during the course of study exhibited pseudo-penis in the head, indicating that a certain level of imposex had progressed in the study site. Relative penis size index (RPSI), an indicator of level of imposex phenomenon varied 59.5-173.4% and this value was relatively higher than the index reported from elsewhere. It was believed that such imposex phenomenon observed in T. clavigera was caused by endocrine disruption by chemical contaminants such as TBTs released from biocidal paints in the port environment.