• Journal of Korean Society of Steel Construction
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• v.15 no.3
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• pp.231-239
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• 2003

Many box girder bridges have been constructed during the past several decades due to their large bending and torsional rigidities as well as aesthetic considerations. However, box girders have shortcoming in that the cross section distorts under an eccentric loading and warps out of the section plane. Therefore, in order to reduce distortional stresses such as distortional warping and transverse bending normal stresses, diaphragms were generally installed in the box girders. Shapes of the diaphragms in steel-box-girder bridges constructed up to date were solid-plate, frame, and truss types. The objectives of this study using parametric study were to evaluate the appropriate stiffness ratio of intermediate diaphragms and then to propose the effective spacing and numbers of intermediate diaphragms based on the evaluated stiffness ratio. Target bridges for this study were straight continuous span bridges with a single-cell steel box section. The parameters for the parametric study were the shape of box section, the span numbers, the equivalent span length, the stiffness of intermediate diaphragms, and the spacing of intermediate diaphragms. From the results of the parametric study, the effective spacing and numbers as well as the stiffness ratio of the intermediate diaphragms will be presented.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.814-820
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• 2000

This papers investigates the combined effects of parameters such as die surface finish, die directionality of stoning, contact pressure and draw speed on the resulting friction factor. Also, this study show the correlation between the NN(Neural Network) and DOE (Design of Experiments) to reduce the number of experiments without the loss of the effects of parameter upon friction factor. The experiments were run in random order with at least three replicates. It was found that the directional stoning orthogonal to the pulling direction is lower friction than directional stoning parallel to the pulling direction using FCD55 die and SPCEN

• Analytical Science and Technology
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• v.14 no.5
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• pp.422-431
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• 2001

One pulp manufacture facility was selected as surveying facility to examine the discharged amount and generation mechanism of dioxins excepts for bleaching stage wastewater. In recovery and finishing process, 2,3,7,8-TCDF, OCDD and OCDF were mainly detected, and the ratio of PCDDs and 1,2,3,4,7,8-HxCDD as the concentration of 2,3,7,8-substitute isomer were discharged which is known as the typical emission pattern of pulp and paper manufacture facility, and the 1,2,3,7,8-PeCDD and 1,2,3,4,7,8-HxCDD were discharged more than 90% in toxic equivalent concentration. Also, the OCDD and 2,3,7,8-TCDF for 2,3,7,8-isomer concentration, and 1,2,3,7,8-PeCDD and 2,3,7,8-TCDF as toxic equivalent concentration were discharged in effluent. The detected PCDDs/PCDFs concentration were surveyed 0.2266 ng-TEQ/L for influent and 0.0377 ng-TEQ/L for effluent.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.43 no.2
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• pp.115-124
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• 2017

The objective of this study was to investigate skin whitening effect of Resorcinol dipentyl ether [1,3-di(pentyloxyl)benzene] by in vitro experiments. Resorcinol dipentyl ether was prepared by alkylation of resorcinol with 1-bromopentane. The reaction products were confirmed by NMR, MS and other analytical equipments. In order to evaluate the skin safety of resorcinol dipentyl ether, the cytotoxicity of the cells constituting the skin (keratinocyte, melanocyte, fibroblast) was analyzed and similar cell viability was observed in all cell lines as compared with the control group. Inhibition of extracellular melanin synthesis effect of resorcinol dipentyl ether was approximately 65.75% at $20{\mu}g/mL$ and inhibition of intracellular melanin synthesis effect of resorcinol dipentyl ether was approximately 53.89% at $20{\mu}g/mL$. The real-time PCR and western blot analysis of mRNA expression and protein expression of tyrosinase, TRP-1, and TRP-2 related to melanogenesis revealed that melanin inhibitory effect of resorcinol dipentyl ether was inhibited from the transcription stage respectively. Finally, this study suggested applicability of Resorcinol dipentyl ether [1,3-di(pentyloxyl)benzene] as a whitening functional cosmetic new material.

• Journal of Korean Society of Steel Construction
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• v.17 no.4 s.77
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• pp.419-429
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• 2005

The objective of this study is to clarify the structural features of members consisting of a connection, as part of the previous study on the CFT column-to-beam tensile connection with a combined cross diaphragm. This connection has the following merits: it evenly distributes the stress on the beam flange and the diaphragm and reduces the stress concentration by improving the stress transfer route and restraining the abrupt deformation of the diaphragm. Finite element analysis was performed to find out the stress transfer through the sleeve, which is an important member of the connection with a combined cross diaphragm. The length and thickness of the sleeve were used as variables for the analysis. The analysis results showed that the length and thickness of the sleeve did not influence the capacity of the connection and played the role of a medium for the transfer of the stress from the diaphragm to the filled concrete. It was proposed that the appropriate length of the sleeve have the same value as the diameter of the sleeve and that the appropriate ratio of the sleeve diameter to the sleeve thickness be 20. Two equations for the evaluation of the load carrying the capacity of the connection were also proposed through the modification of the evaluation equation suggested in the previous study.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2004.11a
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• pp.30-30
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• 2004

• Proceedings of the Optical Society of Korea Conference
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• 2008.07a
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• pp.121-122
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• 2008

• Journal of Korean Society of Steel Construction
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• v.10 no.3 s.36
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• pp.525-536
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• 1998

This paper is concerned with a theoretical study on the local load-carrying capacities of Concrete-Filled Circular Tubular(CFCT) column to H-beam connections by yield line theory. In this paper, the three cases which are assumed the yield line are involved. The first model is a simplified yield line model. The second model is modified by x and kx factors. The last one is a Morita's model. The local load-carrying capacities of CFCT column to H-beam connections has been studied both experimentally and theoretically using the yield line theory. The purpose of this paper is to suggest the basic data for developing the non-diaphragm connection.

• Journal of Korean Society of Steel Construction
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• v.29 no.3
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• pp.237-247
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• 2017

This paper investigates structural characteristics of internal vertical diaphragm and its influence on the connection strength between concrete filled tubular(CFT) column and beam. CFT columns are hybrids that combine two materials in one member. They have the benefits of steel for high tensile strength and ductility and of concrete for high compressive strength and stiffness. Analytical method of the flexural strength of vertical diaphragm to account moment transfer between panel zones is presented using yield line theory. Connection design is verified by a set of monotonic tests and numerical analysis with different diaphragm thicknesses. Plastic zones of CFT flange was found and matched closely to FEM results. Both analytical and experimental results showed good agreement that vertical diaphragm effectively alleviates the stress and transfer the force.

• Journal of Korean Society of Steel Construction
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• v.10 no.2 s.35
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• pp.291-301
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• 1998

This paper is a study on the structural behavior of CFCT(Concrete-Filled Circular Tubular) column to H-beam connections with longitudinal rib. The important parameters are being longitudinal rib or not. variable column thickness(5.8mm. 9.2mm. 12.0mm. 15.0mm) around the joint between CFCT and H-beam and the width of flange to diameter. Test results are summarized for the strength, initial stiffness, failure mode and energy absorption capacities of each specimen. These are compared with the theoretical results(Yield line theory, numerical analysis). Therefore, the purpose of this paper is to investigate the stiffness and the strength of connections to evaluate the structural behavior of the CFCT column to H-beam connections with longitudinal rib.