• Journal of Ocean Engineering and Technology
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• v.29 no.4
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• pp.309-316
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• 2015

Lifting lugs are frequently used in shipyards to transport and turn over the blocks of ships and offshore structures. With the development of shipbuilding technology, blocks have increased in size, and block management technology has assumed a more important role in shipbuilding to enhance the productivity. For the sake of economics, as well as the safe design of a lug structure, a more rational design procedure based on a rigorous structural analysis is needed. This study investigated the strength characteristics of T-type lugs, considering the influence of blocks on which lugs are attached, by varying the in-plane and out-of-plane load direction. In this paper, the ultimate strength is also addressed for cases that include or do not include blocks in the strength analysis. In the present results, when there was a load acting in the normal direction to the block surface, the strength characteristics became poor, and the ultimate strength decreased. This paper ends by describing the need for further study to develop a more rational design for a lug structure.

• Journal of the Korea Concrete Institute
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• v.17 no.6 s.90
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• pp.1065-1074
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• 2005

Due to lack of information, current design methods to calculate bearing strength of connections are tacit about cases in which hybrid coupled walls have connection details of stud bolts and horizontal ties. In this study, analytical study was carried out to develop model for calculating the connections strength of embedded steel section. The bearing stress at failure in the concrete below the embedded steel coupling beam section is related to the concrete compressive strength and the ratio of the width of the embedded steel coupling beam section to the thickness of the shear walls. Experiments were carried out to determine the factors influencing the bearing strength of the connection between steel coupling beam and reinforced concrete shear wall. The test variables included the reinforcement details that confer a ductile behavior in connection between steel coupling beam and shear wall, i. e., the auxiliary stud bolts attached to the steel beam flanges and the transverse ties at the top and the bottom steel beam flanges. In addition, additional test were conducted to verify the strength equations of the connection between steel coupling beam and reinforced concrete shear wall. The results of the proposed equations in this study are in good agreement with both our test results and other test data from the literature.

• The Journal of Korean Physical Therapy
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• v.33 no.1
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• pp.28-33
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• 2021

Purpose: This study examined the effects of heel raise exercises combined with neuromuscular electrical stimulation (NMES) on the muscle strength and postural control ability of subjects with functional ankle instability (FAI). Methods: Twenty-two subjects with FAI participated in this study. They were assigned randomly to two groups: 11 each in the NMES and the sham-NMES groups. Heel raise exercise was applied, and NMES electrodes were attached to the peroneus longus muscles. The NMES group applied NMES during the heel raise exercise. NMES was applied for 20 minutes during the heel raise exercise. The heel raise exercise was performed four times a week for five weeks. The muscle strength and balance error scoring system (BESS) were measured before and after the intervention. Results: A comparison of before and after the intervention within the groups revealed improved muscle strength in the NMES and Sham-NMES groups, but the BESS was improved under all conditions only in the NMES group. The Sham-NMES group showed no improvement in the unstable support surface. Furthermore, when comparing the amount of change before and after the intervention between the groups, there were significant differences in the total score and unstable support in the BESS and muscle strength. Conclusion: NMES had a positive effect on the functional activities of the functional ankle instability subjects, such as balancing on an unstable support surface during postural control and increasing muscle strength.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1788-1790
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• 2003

GIS is a typical power equipment with higher reliability. It is compact and safe because all the energized parts are enclosed by a sealed cylindrical tank which is filled with $SF_6$. Generally gas insulated power equipments like GIS are designed to have sufficient electrical strength to prevent partial discharges under normal operating condition. Despite of the careful processes in manufacturing, transporting and assembling, voids or particles can be created, resulting in partial discharges at electrically weak points. The key factors causing partial discharges in GIS are; particles, voids in solid insulation, protrusions, poor contact of metal components, etc. The particle can be attached on; spacers, electrodes, internal wall of the GIS tank. It also moves in GIS freely. Most of partial discharges are likely to occur when particles are attached to spacers. In this paper, the electrical characteristics of a surface discharge were investigated under various conditions by using simulation program of FEMLAB.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.14-15
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• 2021

Recently, the size of tiles used for bathroom walls in apartment houses is gradually increasing in size. The problem is that when these large-sized tiles are attached by the sticking method, due to the nature of the method, there is a concern about the stability of the attachment to the part (pupil) where the tile and the adhesive are not attached. The problem is serious as it leads to lawsuits in the outbreak court. In addition, it is urgent to verify the adhesion stability of the sticking method because secondary damage occurs due to a safety accident caused by the falling of the tile. Ministry of Land, Infrastructure and Transport [Investigation of defects in apartment houses, calculation of repair cost and defect determination criteria] ① The tile adhesion strength is 0.39N/mm² or more and ② It is specified to fill 80% or more of the base area of the tile backside, but this is currently trendy. It is considered that large-sized tiles need to be verified from multiple angles, and as part of that, we intend to verify the adhesion stability according to the area to be attached to large-sized tiles.

• Architectural research
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• v.7 no.1
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• pp.27-38
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• 2005

No specific guidelines are available for computing the bearing strength of connection between steel coupling beam and reinforced concrete shear wall in a hybrid wall system. There were carried out analytical and experimental studies on connection between steel coupling beam and concrete shear wall in a hybrid wall system. The bearing stress at failure in the concrete below the embedded steel coupling beam section is related to the concrete compressive strength and the ratio of the width of the embedded steel coupling beam section to the thickness of the shear walls. Experiments were carried out to determine the factors influencing the bearing strength of the connection between steel coupling beam and reinforced concrete shear wall. The test variables included the reinforcement details that confer a ductile behavior in connection between steel coupling beam and shear wall, i.e., the auxiliary stud bolts attached to the steel beam flanges and the transverse ties at the top and the bottom steel beam flanges. In addition, additional test were conducted to verify the strength equations of the connection between steel coupling beam and reinforced concrete shear wall. The proposed equations in this study were in good agreement with both our test results and other test data from the literature.

• Journal of Environmental Science International
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• v.5 no.1
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• pp.25-33
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• 1996

This study was conducted to Investigate the biological treatment capability of MMCMAS(Movinig Media Complete Mixing Activated Sludge) reactor for high strength organic wastewater (Average BOD=800mg/l). And this experimental results were compared previous study for low strength organic wastewater (Average HOD=150mg/l) by the same reactor. In this study, we abtained following conclusions ; (1) The laboratory MMCMAS reactor demonstrated that SBOD removal efficiencies of more than 90% can be achieved at organic Bonding rates of 30.9 gBOD/$m^2$/d for high strength organic wastewater and 39.4 gBOD/$m^2$/d for low strength organic wastewater, respectively. (2) The nitrification rates of MMCMAS reactor was found same results of similiar organic loading rates. (3) The ratio of attached biomass to total biomass on the moving media varied in the range of 40 to 63% and 32 to 94% for high and low strength organic wastewater, respectively. And it was varied at the various concentration of influents for the similiar organic loading rates. The sludge production rates was found approximately 0.37 gVSS/$gBOD_{rem}$. in MMCMAS reactor.

• Steel and Composite Structures
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• v.29 no.5
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• pp.659-667
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• 2018

This paper deals with the experimental study on strength the strength and deformation characteristics of short circular Concrete Filled Steel Tube (CFST) columns. Effect of vertical stiffeners on the behavior of the column is studied under axial compressive loading. Intermittently welded vertical stiffeners are used to strengthen the tubes. Stiffeners are attached to the inner surface of tube by welding through pre drilled holes on the tube. The variable of the study is the spacing of the weld between stiffeners and circular tube. A total of 5 specimens with different weld spacing (60 mm, 75 mm, 100 mm, 150 mm and 350 mm) were prepared and tested. Short CFST columns of height 350 mm, outer tube diameter of 165 mm and thickness of 4.5 mm were used in the study. Concrete of cube compressive strength $41N/mm^2$ and steel tubes with yield strength $310N/mm^2$ are adopted. The test results indicate that the strength and deformation of the circular CFST column is found to be significantly influenced by the weld spacing. The ultimate axial load carrying capacity was found to increase by 11% when the spacing of weld is reduced from 350 mm to 60 mm. The vertical stiffeners are found to effective in enhancing the initial stiffness and ductility of CFST columns. The prediction models were developed for strength and deformation of CFST columns. The prediction is found to be in good agreement with the corresponding test data.

• Journal of Aerospace System Engineering
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• v.14 no.6
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• pp.91-99
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• 2020

This study proposes a finite element (FE) model for predicting the bending strength of small gears used in electro-mechanical actuators for aircraft. First, a strain gauge was attached to the tooth root of test gear, and the strain was measured. Subsequently, the FE model was applied to calculate the strain of the test gear, and the modeled strain was compared with the experimental strain. The results confirmed that the FE strain was very close to the experimental strain and the FE model was valid. This FE model was extended to the bending strength analysis of several small gear tooth models. The bending strengths of all the tooth models were almost identical to the ISO theoretical bending strength. Finally, the FE model was validated and the reliability of the modeled bending strength was evaluated through the strain measurement experiment.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.190-191
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• 2021

This study is conducted to provide a method to estimate the setting time and early age compressive strength using D type durometer.Test results indicated that the use of D type Durometer attached with modified needle, which was designed to secure improved accuracy in setting and compressive strength, enables to estimate setting time and the compressive strength at early age.