• Title/Summary/Keyword: Column Form

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Cyclic behavior of steel beam-concrete wall connections with embedded steel columns (II): Theoretical study

  • Li, Guo-Qiang;Gu, Fulin;Jiang, Jian;Sun, Feifei
    • Steel and Composite Structures
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    • v.23 no.4
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    • pp.409-420
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    • 2017
  • This paper theoretically studies the cyclic behavior of hybrid connections between steel coupling beams and concrete shear walls with embedded steel columns. Finite element models of connections with long and short embedded steel columns are built in ABAQUS and validated against the test results in the companion paper. Parametric studies are carried out using the validated FE model to determine the key influencing factors on the load-bearing capacity of connections. A close-form solution of the load-bearing capacity of connections is proposed by considering the contributions from the compressive strength of concrete at the interface between the embedded beam and concrete, shear yielding of column web in the tensile region, and shear capacity of column web and concrete in joint zone. The results show that the bond slip between embedded steel members and concrete should be considered which can be simulated by defining contact boundary conditions. It is found that the loadbearing capacity of connections strongly depends on the section height, flange width and web thickness of the embedded column. The accuracy of the proposed calculation method is validated against test results and also verified against FE results (with differences within 10%). It is recommended that embedded steel columns should be placed along the entire height of shear walls to facilitate construction and enhance the ductility. The thickness and section height of embedded columns should be increased to enhance the load-bearing capacity of connections. The stirrups in the joint zone should be strengthened and embedded columns with very small section height should be avoided.

Evaluation of Blast Resistance of Slab-Column Connections According to the Confinement Effects and Drop Panel (슬래브-기둥 접합부의 구속도 및 드롭패널에 따른 방폭 성능 평가)

  • Lim, Kwang Mo;Lee, Joo Ha
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.37 no.2
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    • pp.451-457
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    • 2017
  • The numerical analysis was conducted to evaluate the behavior of slab-column connection subjected to blast loads using LS-DYNA. The typical form of slab-interior column connection for analysis was considered as a reference specimen and the drop panel slab-interior column was designed to verify the effects of drop panel. The slab-column connections, which were composed of interior, edge and corner column, were additionally analyzed to compare their confinement effects of specimens. Analysis results were contained the failure shape of connection, behavior of member and so on. From the results, the blast-resistant capacities of slab-column connection would be enhanced by reinforcing the drop panel. In addition, the performance of connections could be improved, when the confinement effects were enhanced.

Correction of Minor-Form and Microform Cleft Lip Using Modified Muscle Overlapping with a Minimal Skin Incision

  • Kim, Min Chul;Choi, Dong Hun;Bae, Sung Gun;Cho, Byung Chae
    • Archives of Plastic Surgery
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    • v.44 no.3
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    • pp.210-216
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    • 2017
  • Background In treating minor-form or microform cleft lip, obtaining an optimal result is a challenge because of the visible scarring caused by traditional surgery. We present a refined method using muscle overlapping with a minimal skin incision in patients younger than 3 years, a group characterized by thin muscle. Methods The surgical technique involves restoration of the notched vermillion using Z-plasty, formation of the philtral column using overlapping of an orbicularis oris muscle flap through an intraoral incision, and correction of the cleft lip nasal deformity using a reverse-U incision and V-Y plasty. A single radiologist evaluated ultrasonographic images of the upper lip. Results Sixty patients were treated between September 2008 and June 2014. The age at the time of operation ranged from 6 to 36 months (mean, 26 months). The follow-up period ranged from 8 to 38 months (mean, 20 months) in minor-form cases and from 14 to 64 months (mean, 37 months) in microform cases. A notched cupid's bow was corrected in 10 minor-form cases and 50 microform cases. Ultrasonographic images were obtained from 3 patients with minor-form cleft lip and 9 patients with microform cleft lip 12 months after surgery. The average muscle thickness was 4.5 mm on the affected side and 4.1 mm on the unaffected side. Conclusions The advantages of the proposed procedure include the creation of an anatomically natural philtrum with minimal scarring. This method also preserves the continuity and function of the muscle and provides sufficient augmentation of the philtral column and nostril sill.

Isolated and Identification of Biological Activity Compounds from Leaves and Stem of Paeonia lactiflora Pallas (작약 잎과 줄기의 생리활성 물질 분리 및 동정)

  • Kim, Se-Jong;Park, Jun-Hong;Choi, Seong-Yong;Son, Kun-Ho;Kim, Kil-Ung
    • Korean Journal of Medicinal Crop Science
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    • v.15 no.1
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    • pp.6-11
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    • 2007
  • This study was conducted to identify physiologically active substances from leaves and stems of peony plant. MeOH extracts and column chromatography were employed to isolate active compounds and chemical structure were identified by IR, UV, Mass and NMR. The results obtained can be summerized as followings : Chemical structure of compound 1 was identified as oleanolic acid (white color form) of triterpenoid group, which is firstly identified from the above part of peony. Compound 2 was identified as kaempferol (yellow needle form) of flavonoid group, which was firstly identified from the root, leaf and stem of peony. Compound 3 was identified as methyl gallate (white power form) of phenol group, which was firstly identified from the above part of peony. Compound 4 was identified as astragalin (bright yellow needle form) of flavonoid group, that was firstly identified from the leaf and stem of peony. Compound 5 was identified as paeoniflorin (white color form) of monoterpene group, that was firstly identified from the above part of peony.

Development of One-way Void Support Device for Flexible Table Form (가변형 테이블폼용 일방향 중공관 지지장치 개발)

  • Kwon, Woobin;Lee, Dongmin;Lee, Changsu;Cho, Hunhee;Kang, Kyung-In
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2019.11a
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    • pp.12-13
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    • 2019
  • Flexible Table Form is being used more frequently at the level of formwork in construction site. However, one of the most common structural frameworks, the RC column-beam structure, is having problems in these factors. To improve this problems, this study developed support devices and proposed installation specifications to enable application of the one-way void slab method to flexible table form. It is expected that the effects of reducing the self-weight of the slab in the floor slab construction using flexible table form.

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Purification and Characterization of Cellobiohydrolase from Trichoderma viride (Trichoderma viride가 생산하는 Cellobiohydrolase의 분리 및 특성)

  • 오태광;박관화
    • Microbiology and Biotechnology Letters
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    • v.16 no.3
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    • pp.219-225
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    • 1988
  • Two isozymes of cellobiohydrolase and fifteen isozymes of endoglucanase from Trichodema viride QM 9414 were purified by ammonium sulfate fractionation, Sephadex G-100 column chromatography, DEAE-Sephadex A-50 column chromatography and preparative electrophoresis. The purified cellobiohydrolnse had a molecular weight of 71,000 estimated by electrophoresis and amino acid analysis showed its main amino acids to be in the form of aspartic acid and glutamic acid result-ing from its low pI point of 3.81. The optimum pH and temperature were 5.1 and 5$0^{\circ}C$ respectively.

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Buckling analysis of linearly tapered micro-columns based on strain gradient elasticity

  • Akgoz, Bekir;Civalek, Omer
    • Structural Engineering and Mechanics
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    • v.48 no.2
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    • pp.195-205
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    • 2013
  • The buckling problem of linearly tapered micro-columns is investigated on the basis of modified strain gradient elasticity theory. Bernoulli-Euler beam theory is used to model the non-uniform micro column. Rayleigh-Ritz solution method is utilized to obtain the critical buckling loads of the tapered cantilever micro-columns for different taper ratios. Some comparative results for the cases of rectangular and circular cross-sections are presented in graphical and tabular form to show the differences between the results obtained by modified strain gradient elasticity theory and those achieved by modified couple stress and classical theories. From the results, it is observed that the differences between critical buckling loads achieved by classical and those predicted by non-classical theories are considerable for smaller values of the ratio of the micro-column thickness (or diameter) at its bottom end to the additional material length scale parameters and the differences also increase due to increasing of the taper ratio.

The Beam-Column Strength of Concrete Filled Tubes (콘크리트 충전 각형강관 기둥재의 최대내력)

  • Lee, Myung Jae
    • Journal of Korean Society of Steel Construction
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    • v.9 no.3 s.32
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    • pp.391-400
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    • 1997
  • The objective of this paper is to suggest formula of Concrete Filled Tube Beam-Column members maximum strength by using of numerical analysis and tests. The numerical analysis results are compared with test results for evaluating numerical analysis method. The formula of Limit State Design of Architectural Institute of KOREA is used for basic form of suggestion formula. In order to suggest formula, two methods are used. One is to use the coefficient, and the other is to use the amplified factor of material strength. The formula by two methods are compared with numerical analysis results.

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Rapid Purification of Recombinant Human Lipocortin-I Secreted from Saccharomyces cerevisiae

  • Chung, Bong-Hyun;Nam, Soo-Wan
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.5 no.4
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    • pp.242-246
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    • 2000
  • Human lipocortin-I was expressed as a secretory product by Saccharomyces cerevisiae harboring an expression system consisting of GAL10 promoter, inulinase signal sequence and lipocortin-I terminator. Fed-batch fermentation was carried out to overproduce recombinant human lipocortin-I. The culture medium was desalted and concentrated by ultrafiltration, and then subjected to hydroxyapatite column chromatography. The lipocortin-I was purified to >98% purity by single-step hydroxyapatite column chromato-graphy. However, it was found that the purified lipocortin-I was a proteolytically-cleaved form which was cleaved immediately after the basic amino acid Lys26.

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Effective length factors for the framed columns with variable stiffness (골조구성 변단면 기둥의 유효길이 계수)

  • 이수곤;김순철;오금열
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2001.10a
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    • pp.175-182
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    • 2001
  • Effective length factor approach for framed column design has long played an important design-aid role. This approach, however, is effective only when the columns are in the form of prismatic or uniform cross sections. Structural engineers who have to design or analyse framed columns with variable cross sections need some means to do their job. By using the finite element method, the stability analysis of the isolated compression members with variable cross sections and that of the framed columns are performed. The parameters considered in the stability analysis are taper and sectional property parameters of the columns, the second moment of inertia ratio of beam to column, and beam span to column height ratio. On the basis of the stability analysis results, effective length factor formulas for the columns with variable sections are derived.

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