• Steel and Composite Structures
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• v.44 no.3
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• pp.339-351
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• 2022

A mortar-filled rectangular hollow structural section (RHS) can increase a structural section property as well as a compressive buckling capacity of a RHS member. In this study, the tensile performance of newly developed mortar-filled RHS members was experimentally evaluated with various connection details. The major test parameters were the type of end connections, the thickness of cap plates and shear plates, the use of stud bolts, and penetrating bars. The test results showed that the welded T-end connection experienced a brittle weld fracture at the welded connection, whereas the tensile performance of the T-end connection was improved by additional stud bolts inserted into the mortar within the RHS tube. For the end connection using shear plates and penetrating stud bolts, ductile behavior of the RHS tube was achieved after yielding. The penetrating bars increased load carrying capacity of the RHS. Based on the analysis of the load transfer mechanism, the current design code and test results were compared to evaluate the tensile capacity of the RHS tube according to the connection details. Design considerations for the connections of the mortar-filled RHS tubes were also recommended.

• Steel and Composite Structures
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• v.32 no.3
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• pp.337-346
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• 2019

The present paper tries to contribute fill the gap of application of the component method to tubular connections. For this purpose, one typical joint configuration in which just one component can be considered as active has been studied. These joints were selected as symmetrically loaded welded connections in which the beam width was the same as the column width. This focused the study on the component 'side walls of rectangular hollow sections (RHS) in tension/compression'. It should be one of the main components to be considered in welded unstiffened joints between I beams and RHS columns. Many experimental tests on double-sided I-beam-to-RHS-column joint with a width ratio 1 have been carried out by the authors and a finite element (FE) model was validated with their results. Then, some different analytical approaches for the component stiffness and strength have been assessed. Finally, the stiffness proposals have been compared with some FE simulations on I-beam-to-RHS-column joints. This work finally proposes the most adequate equations that were found for the stiffness and strength characterization of the component 'side walls of RHS in tension/compression' to be applied in a further unified global proposal for the application of the component method to RHS.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2006.03a
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• pp.249-258
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• 2006

In this paper, deformation capacity of steel moment connections with RHS column was investigated. Initially, non-linear finite element analysis of five bate steel beam models was conducted. The models were designed to have different detail at their beam-to-column connection, so that the flexural moment capacity was different respectively. Analysis results showed 4hat the moment transfer efficiency of the analytical model with RHS-column was poor when comparing to model with WF(Wide flnage)-column due to out-of-plane deformation of the RHS-column flange. The presence of scallop and thin plate of RHS column was also a reason of the decrease of moment transfer efficiency, which would result in a potential fracture of tile steel beam-to-column connections. Further test on beam-to-column connections with RHS column revealed that the moment transfer efficiency of a beam web decreased due to the out-of-plane deformation of column flange, which led to premature failure of the connection.

• Structural Engineering and Mechanics
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• v.63 no.3
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• pp.385-400
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• 2017

This paper presents an experimental study on the behavior of axially-loaded steel RHS (rectangular hollow section) compression members that are partially reinforced along their lengths with welded steel plates. 28 slender column tests were carried out to investigate the effects of the slenderness ratio of the unreinforced member and the ratio of the reinforced length of the member to its entire length. In addition to the slender column tests, 14 stub-column tests were conducted to determine the basic mechanical properties of the test specimens under uniform compression. Test results show that both the compressive strength and stiffness of an RHS member can be increased significantly compared to its unreinforced counterpart even when only the central quarter of the member is reinforced. Based on the limited test data, it can be concluded that partial reinforcement is, in general, more effective in members with larger slenderness ratios. A simple design expression is also proposed to predict the compressive strength of RHS columns partially reinforced along their length with welded steel plates by modifying the provisions of AISC 360-10 to account for the partial reinforcement.

• Proceedings of the Korea Information Processing Society Conference
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• 2021.11a
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• pp.364-366
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• 2021

본 논문은 비전 기술을 기반으로 RHS 칼라차트를 이용하여 작물의 색채를 측정하는 특성조사기준에 관한 연구를 수행하였다. 다양한 색상을 가진 작물의 색채를 측정하기 위해 시료 채취 후 표준광원 촬영장치 광원 6500K 환경하에 촬영한 영상을 기반으로 분석 위치를 관심영역 선정 후, k-mean clustering을 활용한 세그먼테이션 방법을 통해 대표 RGB 색상을 획득한다. 획득한 RGB 색상과 RHS 칼라차트의 RGB 색상을 유클리디언 거리를 이용하여 최소화하는 RHS 칼라차트 정보를 추정하였다. 7가지 작물 시료에 대해 작물 형질 분석 전문가들이 측정한 결과와 비교 시 전체 평균 △E 5.013의 오차를 결과로 도출하였다.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.11 no.6
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• pp.112-119
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• 2008

In order to elucidate growth characteristics, physiological responses and leaf color changes of Physocarpus opulifolius 'Diabolo' and Ophiopogon planiscapus 'Nigrescens'. These experiments were investigated under various shading levels. Growth of P.opulifolius 'Diabolo' was better at 30% shading level but physiological activities were double at strong light condition. Dark purple color was observed at 85% shading level and color was dim down when shading level decreased. Color was deep purple(RHS 202A) at 85% shading and green(RHS 139A) at 0%, These results imply that ornamental value was increased when shading level increased for P. opulifolius 'Diabolo'. Growth and highest physiological activity of O. planiscapus 'Nigrescens' were observed at 0% shading level and dark red color(RHS 202A) was also observed at 0% shading level. These results imply that ornamental value was increased when shading level decreased for O. planiscapus 'Nigrescens'.

• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.4 s.50
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• pp.67-76
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• 2006

In this paper the moment transfer efficiency of a web and the strain concentration at the RHS (Rectangular Hollow Section) column-to-steel beam connections was evaluated. Initially, non-linear finite element analysis of five bare steel beam models was conducted. The models were designed to have different detail at their beam-to-column connection, so that the flexural moment capacity was different respectively. Analysis results showed that the moment transfer efficiency of the analytical model with RHS-column was poor when comparing to model with WF(Wide Flnage)-column due to out-of-plane deformation of the RHS-column flange. The presence of scallop and thin plate of RHS column was also a reason of the decrease of moment transfer efficiency, which would result in a potential fracture of the steel beam-to-column connections. Analytical results were compared with the previous experimental results. The analytical and the previous experimental results showed that the strain concentration was inversely proportional to the moment transfer efficiency of a beam web and the deformation capacity of connection was poor as their moment transfer efficiency degrades. Further finite element analyses of composite beam with a floor slab revealed that the neutral axis moved toward the top flange and the moment transfer efficiency of a beam web decreased, which led to premature failure of the connection.

• Investigative Magnetic Resonance Imaging
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• v.25 no.3
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• pp.197-200
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• 2021

Ramsay Hunt syndrome (RHS) is a disease caused by varicella-zoster virus (VZV) infection that can be diagnosed through clinical symptoms with or without imaging evaluations. The typical features of RHS on imaging evaluation include signal changes and enhancement in the internal auditory canal (IAC) nerves, and the labyrinthine segment of cranial nerve VII (CN VII) and cranial nerve VIII (CN VIII). In some patients, inner ear structure (cochlear and vestibular apparatus) is involved in RHS. Neurologic complications, such as encephalitis and meningitis, are rare in RHS, but are known to occur. Therefore, magnetic resonance imaging (MRI) is necessary to detect both abnormal signal intensity in the IAC, CN VII, CN VIII, inner and ear structure, and CNS complications. We report an RHS patient with CN VII, VIII, and leptomeningeal enhancement within the cerebellar folia on 10-min delayed, contrast-enhanced (CE), three-dimensional fluid-attenuated inversion recovery (3D-FLAIR) imaging.

• Steel and Composite Structures
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• v.10 no.6
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• pp.489-500
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• 2010

The rigid connections of I-beams to Rectangular Hollow Sections (RHS) in steel structures usually behave as semi-rigid connection. This behavior is directly related to the column face deformation. The deformation in the wall of RHS column in the connection zone causes a relative rotation between beam end and column axis, which consequently reduces the rigidity of beam-column connection. In the present paper, the percentages of connection rigidity reduction for serviceability conditions are evaluated by using the finite element analysis. Such percentages for RHS columns without internal stiffeners are considerable, and can be calculated from presented graphs.

• Korean Journal of Plant Resources
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• v.31 no.3
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• pp.211-217
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• 2018

Hibiscus syriacus (H. syriacus) as the national flower of Korea has been used as the herbal medicine in Asia. In this study, we evaluated the anti-inflammatory effect of 70% ethanol extracts from the root of Hibiscus syriacus (RHS-E70) and elucidated the potential signaling pathway in LPS-stimulated RAW264.7 cells. RHS-E70 dose-dependently suppressed NO production by inhibiting iNOS and IL-${\beta}$ expression in LPS-stimulated RAW264.7 cells. RHS-E70 inhibited the phosphorylation and degradation of $I{\kappa}B-{\alpha}$, which contributed to the inhibition of p65 nuclear accumulation and NF-${\kappa}B$ activation. Furthermore, RHS-E70 suppressed the phosphorylation of ERK1/2 and p38, which results in the inhibition of ATF2 phosphorylation and subsequent nuclear accumulation. These results indicate that RHS-E70 may exert anti-inflammatory activity by inhibiting NF-${\kappa}B$ and MAPK/ATF2 signaling. From these findings, RHS-E70 has potential to be a candidate for the development of chemopreventive or therapeutic agents for the inflammatory diseases.