• Steel and Composite Structures
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• v.5 no.5
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• pp.375-394
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• 2005

An experimental study was conducted to develop a new base plate anchorage system for concrete filled tubular column under an axial load and a moment. The column was connected to a concrete foundation using ordinary deformed reinforcing bars that are installed at the inside and outside of the column. In order to investigate the moment resisting capacity of the system, horizontal cyclic loads are applied until the ultimate condition is reached with the axial load held constant. To derive a design method for moment resisting capacity, the reinforced concrete section approach was investigated with the assumption of strain compatibility. The results by this approach agreeded well with those of experiments when the bearing pressure of confined concrete and tangent modulus of steel bars are assumed appropriately. Also, it was found that the column interaction curve can be used to predict the yield strength of the base plate system.

• Journal of Korean Society of Steel Construction
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• v.27 no.1
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• pp.119-129
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• 2015

Due to reduced self weight and alleviated wind effect, the multi-column wind towers that consist of a number of circular tubes as vertical members interconnected with horizontal brace members can be a substitute for the large-scale single cylinder wind towers. It is critical to guarantee strengths of tubular joints where vertical and horizontal members are structurally connected in order to make the whole multi-column system behave as a single tower structure. In this study, strength evaluation has been conducted for T-type tubular joints that are applicable in multi-column towers. Four of available design codes, i.e., AISC, Eurocode3, ISO 19902, CIDECT have been investigated and predictor equations in the considered design codes were validated and discussed through parametric numerical study on slenderness ratios of chords and braces at joints.

• Journal of the Korean Society of Clothing and Textiles
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• v.35 no.8
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• pp.968-981
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• 2011

This study examines the effect of the structure of Intarsia and Jacquard knit on mechanical properties of knit fabrics to suggest data for knit design. Intarsia and 7 types of Color Jacquard (Floating Jacquard, Normal Jacquard, Bird's eye Jacquard, Tubular Jacquard, Ladder's back Jacquard, Blister Jacquard, and Transfer Jacquard) were used. The samples with a gauge of 14 were knitted using 100% wool 2/48's yarn by Shima Seiki SIG computer knitting machine. The Objective Hand was measured by KES-FB system and HV and THV were calculated by the formula of KN-402-KT and KN-301-winter respectively. The results showed that Intarsia and Floating Jacquard are thin, flexible and light, Bird's eye Jacquard is slick, flat and slim, Tubular Jacquard is stiff and undrapable, Ladder's back Jacquard is difficult in shearing deformation and relatively bulky, Blister Jacquard is thickest and transfer jacquard is uneven in surface contour. The selection of proper structure is important for the knit apparel production since the thickness and weight of knit determine the amount of yarn needed and consequently the production cost. The hands of Ladder's back Jacquard and Tubular Jacquard are superior to those of other structures. Intarsia and Floating Jacquard which are thin, light and flexible seem to be good structures for designs showing a body silhouette whereas, Bird's eye Jacquard, Tubular Jacquard and Blister Jacquard (which are thick, heavy, and stiff) are suitable for a boxy silhouette.

• Tunnel and Underground Space
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• v.28 no.6
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• pp.620-634
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• 2018

The NTR(New Tubular Roof) method was used to secure the stability of the tunnel and minimize the subsidence of the road. The tunnel was constructed at about 7.5 meters deep below the highway. with a width of about 21 meters. Following the NTR method, 13 steel pipes with a diameter of 2.3 meters were digged and pushed in longitudinally along the tunnel profile and cut out sides of pipes to connect to adjacent pipes, then filled the inside of pipes and the connected space between pipes with concrete to complete the lining of the tunnel to be excavated. As the steel pipes were digged in sequentially, the area of relaxation was connected to each other and behaves like a gradually widening tunnel. When the steel pipes were digged in to the widest points of the tunnel, the settlement rate of the road surface was increasing to the maximum as 2.2 mm and the total settlement until the lining construction was approximately 7.7 mm. After that, by excavating a tunnel inside the pre-installed lining, an additional settlement of about 4.3 mm was occurred, resulting in the total settlement of about 11.8 mm after completing of tunnel construction.

• Clean Technology
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• v.16 no.4
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• pp.297-303
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• 2010

Effect of interconnect structure on the cell performance in anode-supported tubular solid oxide fuel cell (SOFC) has been investigated in this study, employing the Fluent CFD solver. For the robust and reliable theoretical analysis corroborating experimental results, it is of great importance to elucidate the role of interconnect which is electrically connected with electrodes on the cell characteristics. From the fact that the thin interconnect provides the enhanced cell performance, it is revealed that the interconnect thickness is a key parameter that is able to effectively control the ohmic resistance. Under the constant thickness condition, the cell performance does not considerably change with the variation of interconnect width. This is because the current passage along with circumferential direction is not effectively altered by the change of interconnect width in tubular SOFC system.

• Steel and Composite Structures
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• v.22 no.6
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• pp.1217-1238
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• 2016

Mega composite structure systems have been widely used in high rise buildings in China. Compared to other structures, this type of composite structure systems has a larger cross-section with less weight. Concrete filled steel tubular (CFST) laced column to box-beam connections are gaining popularity, in particular for the mega composite structure system in high rise buildings. To enable a better understanding of the destruction characteristics and aseismic performance of these connections, three different connection types of specimens including single-limb bracing, cross bracing and diaphragms for core area of connections were tested under low cyclic and reciprocating loading. Hysteresis curves and skeleton curves were obtained from cyclic loading tests under axial loading. Based on these tested curves, a new trilinear hysteretic restoring force model considering rigidity degradation is proposed for CFST laced column to box-beam connections in a mega composite structure system, including a trilinear skeleton model based on calculation, law of stiffness degradation and hysteresis rules. The trilinear hysteretic restoring force model is compared with the experimental results. The experimental data shows that the new hysteretic restoring force model tallies with the test curves well and can be referenced for elastic-plastic seismic analysis of CFST laced column to composite box-beam connection in a mega composite structure system.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.1
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• pp.139-142
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• 1998

To obtain informations for construction of a mass culture system, factors affecting on the specific growth rate of marine Chlorella sp. purchased from the Chungmu Laboratory of the South Sea Fisheries Institute, the National Fisheries Research and Development Agency were investigated using a vertical tubular photobioreactor (VT-PBR) system. Optimal temperature, illumination intensity, air- and $CO_{2-}$ flow rate for Chlorella sp. were $20^{\circ}C$, 6,000 lux, 0,56 vvm and 0.028 vvm, respectively.

• KSBB Journal
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• v.13 no.1
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• pp.101-107
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• 1998

Carbon dioxide is estimated to be responsible for 60% of the global warming effect, and this percentage is tending upward. Studies on removal and fixation of $CO_2$ in the flue gas are recognized as one of the important roles of the future biotechnology. Photobiological systems have considerably higher photosynthetic efficiency than conventional biomass system. The experiment for the photosynthetic fixation of $CO_2$ and the biomass production was performed with various initial cell concentration in a tubular photobioreactor and a bubble column $CO_2$ contactor with a gas sparger of $CO_2$ -enriched air(0.03~20%). Synechocystis PCC 6803 could grow at 10~20% $CO_2$ content under pH control. The highest specific growth rate, 0.0258 $h^{-1}$ , was obtained at 5% $CO_2$-air mixture. The maximum cell production rate, 0.2784 g/L.day, was obtained when the initial cell concentration was 0.45 g/L at 5% $CO_2$ -air mixture. The maximum cell concentration was 2.03 g/L in the tubular photobioreactor when the light intensity was $45.5{\mu}$ $E/m^2$ . s. This system showed 0.482 g $CO_2$ /L . day of the $CO_2$ fixation.

• Journal of the Korean Solar Energy Society
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• v.32 no.spc3
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• pp.207-212
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• 2012

It is important to produce the high-temperature and high-pressure air for the concentrated solar power system using the combined cycle. In this paper, we designed two types of tubular receivers to heat up the compressed air and provided their preliminary experimental results for performance evaluation and further improvements. The developed receivers are in a square cavity shape surrounded by flow conduits for easy scale-up and radiation loss reduction. The two receivers were tested with 5 bar air in the KIER solar furnace and evaluated in terms of the outlet temperature and the efficiency.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.7
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• pp.1329-1335
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• 2009

This paper presents the flow characteristics in the fluid circulation loop using the tubular type linear induction motor(TLIM) electromagnetic pump. A TLIM pump was designed using the equivalent and genetic algorithm for the flow system of 40[1/min]. The flow characteristics are analyzed by coupling the Maxwell equations with the Navier-Stokes equation. The analysis algorithm also takes account of the effects of the thrust. The flow characteristics are analysed with the proposed method and compared with the commercial program and experiment and discussed.