• Title, Summary, Keyword: short column

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Capacity and the moment-curvature relationship of high-strength concrete filled steel tube columns under eccentric loads

  • Lee, Seung-Jo
    • Steel and Composite Structures
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    • v.7 no.2
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    • pp.135-160
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    • 2007
  • Recently, CFT column has been well-studied and reported on, because a CFT column has certain superior structural properties as well as good productivity, execution efficiency, and improved rigidity over existing columns. However, CFT column still has problems clearing the capacity evaluation between its steel tube member and high-strength concrete materials. Also, research on concrete has examined numerical values for high-strength concrete filled steel square tube columns (HCFT) to explain transformation performance (M-${\phi}$) when a short-column receives equal flexure-moment from axial stress. Moment-curvature formulas are proposed for HCFT columns based on analytic assumption described in this paper. This study investigated structural properties (capacity, curvature), through a series of experiments for HCFT with key parameters, such as strength of concrete mixed design (58.8 MPa), width-thickness ratio (D/t), buckling length to sectional width ratio (Lk/D) and concrete types (Zeolite, Fly-ash, Silica-fume) under eccentric loads. A comparative analysis executed for the AISC-LRFD, AIJ and Takanori Sato, etc. Design formulas to estimate the axial load (N)-moment (M)-curvature (${\phi}$) are proposed for HCFT columns based on tests results described in this paper.

The Influence of Cation Exchange Capacity of Zeolite and Solution Chemistry on the Transport of Bacteria (제올라이트의 양이온 교환 용량 및 용액의 화학적 특성에 따른 박테리아의 거동 특성 비교)

  • Kim, Mun-Ju;Lee, Chang-Hee;Yoo, Soo-Cheul;Park, Seong-Jik
    • Journal of Korean Society of Water Science and Technology
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    • v.25 no.5
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    • pp.3-11
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    • 2017
  • Bacteria attachment on zeolite with different cation exchange capacity (CEC) was investigated, and zeolite with low CEC (LC-ZL), zeolite with medium CEC (MC-ZL), and zeolite with high CEC (HC-ZL) were used. Column experiments were performed varying column length (10-15 cm), pH (4-8), and ionic strength (0-80 mM). As the increase of the column length, removal percentage was increased but sticking efficiency was not dependent on the column length. The increase of pH decreased both removal percentage and sticking efficiency. Bacteria attachment onto zeolite was increased as the increase of the ionic strength from 0 to 20 mM but it was decreased above 20 mM of the ionic strength. At long (20 cm) or short (10 cm) column length, the differences of removal percentage of LC-ZL, MC-ZL, and HC-ZL were not observed. The bacteria attachment onto MC-ZL and HC-ZL was not significantly different at high ionic strength. Solution chemistry should be considered when the selection of appropriate zeolite for the removal of bacteria.

Axial Compressive Behavior of the R/C Short Columns Strengthened with CFS (탄소섬유쉬트로 횡보강된 R/C단주의 압축거동)

  • Shin, Sung-Woo;Bahn, Byong-Youl;Lee, Kwang-Soo;Ahn, Jong-Moon;Hwang, Jun-Ho
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.2 no.4
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    • pp.201-208
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    • 1998
  • To observe the confinement effects of Carbon Fiber Sheet(CFS) on the high-strength R/C short columns, Fifteen specimens with CFS were manufactured and tested under uni-axial compressive load. Major variables of this study are amount, spacing, type of CFS and amount of transverse steel. Increasing the amount of transverse steel and CFS, compressive strength and axial rigidity is improved. R/C columns with transverse steel and CFS exhibited less axial stress than columns with only CFS. From the test results, it is shown that the area confined with transverse steel and CFS is considerably important to evaluate axial stress of R/C short columns.

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Determination of Taurine in Preparations by Amino Acid Autoanalyzer (아미노산 분석기에 의한 제제중 Taurine의 분리 정량에 관한 연구)

  • 박만기;한달수
    • YAKHAK HOEJI
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    • v.28 no.1
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    • pp.21-23
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    • 1984
  • High performance amino acid analyzing method has been developed for the routine analysis of taurine in preparations. Ion-exchange resin #2619 Hitachi Custom Ion-Exchange Resin, $2.6(I.D.){\times}150$(length)mm was used as column, buffer I, pH 3.3 as mobile phase. The retention time of taurine was 7 minutes. Calibration curve by peak height for standard taurine was linear from 2.5ppm to 25ppm. The reproducibility showed relative standard deviation $\pm$1.9% when analyzed 10 times for standard solution. The samples could be continuously analyzed without regenerating the resin between samples. Five samples were applied to column every 12 min. and then the resin was regenerated for 30 min. during one analyzing cycle time, 90 min. The automatic amino acid analyzer has made it possible to assay multiple samples in a relatively short period of time using the analytical magnetic program card. The high sensitivity and specificity of the analytical column of the automatic amino acid analyzer permits the routine analysis of taurine in preparations.

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Column Generation Approach to the Constraint Based Explicit Routing Problem in MPLS Based IP Networks (MPLS 기반 IP 방에서 열생성 기법을 이용한 경로 설정 해법)

  • Kim Deokseong;Park Sungsoo
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • pp.410-417
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    • 2002
  • We consider the constraint based explicit routing problem in MPLS based IP Network. In this problem, we are given a set of traffic demands and a network with different link capacities. The problem is to assign the demand commodities to the paths in the network while minimizing the maximum link load ratio. We formulate this problem as an integer programming problem and propose an efficient column generation technique. To strengthen the formulation, we consider some valid inequalities. We also incorporate the column generation technique with variable fixing scheme Computational results show that the algorithm gives high quality solutions in a short execution time.

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Effective Partitioning of Static Global Buses for Small Processor Arrays

  • Matsumae, Susumu
    • Journal of Information Processing Systems
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    • v.7 no.1
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    • pp.85-92
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    • 2011
  • This paper shows an effective partitioning of static global row/column buses for tightly coupled 2D mesh-connected small processor arrays ("mesh", for short). With additional O(n/m (n/m + log m)) time slowdown, it enables the mesh of size $m{\times}m$ with static row/column buses to simulate the mesh of the larger size $n{\times}n$ with reconfigurable row/column buses ($m{\leq}n$). This means that if a problem can be solved in O(T) time by the mesh of size $n{\times}n$ with reconfigurable buses, then the same problem can be solved in O(Tn/m (n/m + log m)) time on the mesh of a smaller size $m{\times}m$ without a reconfigurable function. This time-cost is optimal when the relation $n{\geq}m$ log m holds (e.g., m = $n^{1-\varepsilon}$ for $\varepsilon$ > 0).

A Case Study on the Installation and Operation of the Standing Column Well Method (우물관정형(SCW공법) 지열히트펌프 시스템의 설치 및 운영사례)

  • Na, Sang-Min;Park, Si-Sam;Park, Jong-Hun;Rhee, Keon-Joong;Kim, Tae-Won
    • 한국신재생에너지학회:학술대회논문집
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    • pp.592-595
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    • 2009
  • In recent years, geothermal heat pump (GHP) systems have become increasingly popular for heating and cooling in buildings. The Standing Column Well (SCW) method is one of the most efficient GHP system. Because it use groundwater for heat transfer material. In SCW systems, water is re-circulated between the well and the building (heat pump). It is only a short time since this method has been applied in domestic. So we have to refer to the developed countries' guides and manuals of SCW. In this paper, several design and construction points of SCW method are filed. We used real operation data of SCW system at Chong-Ju Univ. site for economical efficiency analysis. As a result, the payback period of Chong-Ju Univ. site is calculated at 7.23 years.

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An Experimental Study for Development of Details and Design Method of CFT Column-to-RC Flat Plate Connections (CFT기둥 철근콘크리트무량판 접합부 상세 및 설계법 개발을 위한 실험연구)

  • Lee, Cheol-Ho;Kim, Jin-Won;Lee, Jin-Hyeok;Park, Cheol-Su;Oh, Jeong-Gun
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • pp.203-210
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    • 2005
  • This paper summarizes full-scale test results on CFT column to flat plate connections subjected to gravity loading. CFT construction has gained wide acceptance in a relatively short time in domestic building practice due to its various structural and construction advantages. Constructing the floor as flat plate is often regarded as being essential for both cost savings and rapid construction. However, efficient details for CFT column to flat plate connections have not been proposed yet, and their development is urgently needed. Based on some strategies that include maximizing economical field construction, several connecting schemes were proposed and tested in this study. Test results showed the proposed connection details can exhibit strength and stiffness comparable to or greater than those of R/C flat plate counterpart.

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Distillation design and optimization of quaternary azeotropic mixtures for waste solvent recovery

  • Chaniago, Yus Donald;Lee, Moonyong
    • Journal of Industrial and Engineering Chemistry
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    • v.67
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    • pp.255-265
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    • 2018
  • The huge amount of solvents used in the semi-conductor and display industry typically result in waste of valuable solvents which often form complex azeotropic mixtures. This study explored a recovery process of a quaternary waste solvent, comprising methyl 2-hydroxybutyrate, propylene glycol monomethyl ether acetate, ethyl lactate, and ethyl-3-ethoxy propionate. In this study, a novel shortcut column method with a graphical approach was exploited for the distillation column design of complex quaternary azeotropic mixtures. As a result, the proposed shortcut method and design procedure solved the complex separation paths successfully with less computational efforts while achieving all requirements for component purity.

Bearing Capacity Characteristics of Stone Column by Numerical Analysis (수치해석에 의한 쇄석기둥의 지지력 특성)

  • Chun, Byung-Sik;Kim, Baek-Young
    • Journal of the Korean Geoenvironmental Society
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    • v.5 no.1
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    • pp.75-84
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    • 2004
  • Stone column is one of the soft ground improvement method, which can enhance ground conditions such as the settlement reduction and the increasement of bearing capacity with applying the crushed stone instead of sand. In recent, general construction material, sand is in short of supply. Therefore, the bearing capacity improvement by the stone column is considered as the alternative method needed in many cases so the bearing capacity estimation is considered as important point. Nevertheless, adequate estimation methods to predict bearing capacity of stone column considering stone column and improvement effect of ground is not yet prepared. For the analysis of above mentioned points, the behavior of stone column were simulated as numerically on various property cases of crushed stone and surrounded ground. Through the numerical analysis of simulation results, the formula for the bearing capacity estimation of stone column was suggested. This formula was verified by comparing the prediction result of in situ test.

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